CN100371616C

CN100371616C - Bearing unit and rotation drive device using the same

Info

Publication number: CN100371616C
Application number: CNB2004800000909A
Authority: CN
Inventors: 宍户祐司; 矢泽健一郎; 金子猛; 高田清幸; 佐藤弘史; 柿沼义昭; 中村一郎
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2003-01-10
Filing date: 2004-01-08
Publication date: 2008-02-27
Anticipated expiration: 2024-01-08
Also published as: CN1697936A; JP2004263707A; JP4078983B2

Abstract

A bearing unit ( 90 ) for rotatably supporting a shaft ( 100 ) comprises a seamless holding member ( 120 ) with a gap allowing a shaft to run through and extend to the outside, a bearing ( 130 ) arranged in the inside of the holding member to rotatably support the shaft so as to make it radially revolvable, an anti-shaft-release member ( 115 ) fitted to the shaft so as to abut the bearing in order to prevent the shaft from slipping away in the thrusting direction and a space-forming member ( 113 ) arranged in the inside of the holding member so as to secure a space around the anti-shaft-release member. A bearing unit may further comprise an lubricating oil seal member and the space-forming member may be used to form a passage way for lubricating oil to prevent lubricating oil from leaking.

Description

Bearing unit and the rotating driving device that uses this bearing unit

Technical field

The present invention relates to the bearing unit of rotatably mounted axle and the rotating driving device that uses this bearing unit.

The application's case is to be that the basis requires preference in Japan in the Japanese application for a patent for invention 2003-053231 of the Japanese application for a patent for invention 2003-300529 of application on August 25th, 2003, application on February 28th, 2003 and the Japanese application for a patent for invention 2003-004928 of application on January 10th, 2003, has quoted these application cases in the application's case.

Background technique

The rotatably mounted axle of bearing unit, this bearing unit for example are arranged in the rotating driving device such as fan motor.

The axle of the bearing unit of this structure be shaped as I font (being also referred to as straight line type), use lubricant oil to make it rotatably to support.Specifically, the Japanese patent of invention example that No. 3265906 communique is put down in writing is arranged.The bearing unit 540 that this communique is put down in writing has structure shown in Figure 1.As shown in Figure 1, this bearing unit 540 is with radial bearing 542 and thrust-bearing 543 rotatably mounted axles 541.Radial bearing 542 is by holding member 544 supportings; Thrust-bearing 543 is by base plate 545 supportings.On the axle 541 fall-out preventing component 546 is installed.

This bearing unit 540 since its structural former thereby plug-in mounting axle fall-out preventing component 546 at last therefore, need at last to adopt thrust-bearing 543 and base plate 545 are assembled into the packaging technology that holding member 544 gets on.Owing to adopt this packaging technology, therefore, the axle fall-out preventing component 546 for installation shaft 541 must make the bearing housing of bearing unit 540 be made of a plurality of parts such as holding member 544 and base plates 545.In this case, sealing is difficult to make the two joining portion 548 of holding member 544 and base plate 545 reach fully, therefore, exists and is filled in inner lubricant oil the possibility of leaking takes place.

In addition, the end face 547 of radial bearing 542 is to exposing outside, and is also very big from the possibility that lubricating oil splash, evaporation take place here.

As mentioned above, therefore existing bearing unit 540, plays a part and will all around get up to prevent that oil leak, the bearing housing that splashes from being to be made of a plurality of parts because of being provided with the axle fall-out preventing component 546 of axle 541.Therefore, exist easily the problem that oil leak takes place from the joining portion of each parts of constituting bearing housing, and, exist the problem that complex process causes cost to increase.

As other bearing unit that proposed in the past, a kind of like this scheme is for example arranged, promptly, radial bearing that is to use forms such as sintered metal bearing or Hydrodynamic bearing that adopts in the gear mechanism of the axle of metal manufacturings such as supporting stainless steel and the thrust-bearing of making by macromolecular material, bearing housing parts with metal manufacturings such as brass support each bearing, in order to prevent to be filled in the oil leak of perimembranous in the radial bearing, be provided with Sealing.But this bearing unit is owing to be with radial bearing and thrust-bearing free rotary ground supporting axle, thereby can be with respect to bearing housing parts supporting axle rotatably.

This bearing unit must use lubricant oil so that axle well rotates, and prevents that by Sealing lubricant oil is to external leakage.Lubricant oil might ooze out from any slit and leak into the outside of bearing unit, and this becomes the reason that shorten working life, and therefore, it is necessary that the joining portion of each parts is sealed fully.For this reason, the inventor is in Japanese application for a patent for invention 2001-289568 number, the scheme that bearing housing parts and the joining portion between the Sealing with the metal manufacturing seal with ultraviolet hardening binder etc. has been proposed, in addition, in Japanese application for a patent for invention 2002-34331 number, all resin manufacture bearing housing parts have been proposed and the scheme that Sealing is integrally formed.

Even if such bearing means, it also is difficult keeping sufficient stability and reliability.

For example, be in the structural type of separate part at bearing housing parts and Sealing, make and realize linking fully between the two or engage to be difficult, be difficult to prevent conscientiously the leakage of lubricant oil.In addition, it is very complicated and very difficult operation that polymeric seal materials such as binder are not coated with along the joining portion complete cycle with having omission, and is difficult to confirm whether the slit is sealed fully.Therefore, perhaps can't obtain enough reliabilities, perhaps cost is very high.

The leakage of lubricant oil will cause guaranteeing stable working life, be the major reason that the bearing unit reliability reduces, and, also may cause harmful effect (chemical erosion phenomenon etc.) to the parts that are arranged on the bearing unit outside.In the time of in for example being applied to hard disk drive (HDD), the leakage of the lubricant oil of being made up of organic material is to produce distortion or the reason of atomize (card atomizing) etc.

And in bearing housing parts and the two integrally formed structural type of Sealing, though there is not the slit between the two, but under the state that axle is supported with bearing during forming axis bearing sleeve parts, be formed at must be very little as the sealed department and the space between the axle of the part of bearing housing parts occasion, guarantee that its precision is very difficult.For example, the discreteness of pore volume between Sealing and the axle will influence the position (highly) of pasta, therefore, and more at most might the Yin Wendu rising as if oil mass or pressure change and cause lubricant oil outwards to splash.

As the another kind of bearing unit of rotatably mounted running shaft, the international example that the WO03/027521 publication is put down in writing that discloses is arranged.This bearing unit 660 as shown in Figure 2, even the occasion that the pressure in environmental changes such as pressure change or temperature variation cause the bearing housing that is filled with viscous fluid changes can prevent conscientiously that also viscous fluid is to the bearing housing external leakage.

This bearing unit 660 is provided with radial bearing 644 and thrust-bearing 650, rotatably mounted running shaft 641, be filled with lubricant oil 653, between the inner peripheral surface of the outer circumferential face of bearing housing 661 and urceolus 667 that this bearing housing 661 is fenced up, be provided with exhaust passageway 662.

Exhaust passageway 662 be for the air in the bearing housing 661 that prevents bearing unit 660 along with air pressure expands because of reasons such as variable height reduce, lubricant oil 653 is provided with to the external leaks of bearing unit 660.Exhaust passageway 662 for example can be provided with one or more on bearing housing 661.Such as, in this bearing unit 660, be formed with 3 in the periphery of the bearing housing 661 set angle of being separated by.Exhaust passageway 662 can be simply accommodates under the state of radial bearing 644 with thrust-bearing 650 at bearing housing 661 and is shaped simultaneously during packet shaping integratedly.That is,, also can when going out bearing housing 661 and thrust-bearing 650, ester moulding be shaped even exhaust passageway 662 has complicated shape.

Owing to be provided with this exhaust passageway 662, when installing in running shaft 641 insertion radial bearings 644, air can be discharged along with its insertion.

In this bearing unit 660, exhaust passageway 662 has the 1st path 663 and the 2nd path 664.The 1st path 663 is the paths that radially form near the inner space 665 the thrust-bearing 650 along bearing housing 661.The inner space 665 at thrust-bearing 650 places that the inboard of the 1st path 663 forms with giving prominence to from the bottom closure 647 of bearing housing 661 links to each other.The outside of the 1st path 663 links to each other with the 2nd path 664.The 2nd path 664 be the outer circumferential face from bearing housing 661 expose and with axially the forming of bearing housing 661 with paralleling.Even if having the 1st path 663 and the 2nd path 664 exhaust passageway 662 of complicated shape like that as mentioned above, also can in be shaped plastic bearing housing 661 and thrust-bearing 650, be shaped simply.

As bearing unit 660, owing to be provided with exhaust passageway 662 as mentioned above, thereby the inside of bearing housing 661 is not airtight, therefore, even running shaft 641 and bearing housing 661 relative rotations, static pressure in the bearing housing 661 can not reduce yet, thereby residual air expansion can not take place and phenomenon that lubricant oil is extruded.

This bearing unit 660 is because the part of itself and external communications has a plurality of parts such as exposed division of exhaust passageway 662 and running shaft 641, thereby an one part becomes air suction inlet, and another part becomes the lubricant oil exhaust port, and therefore, lubricant oil might splash when being subjected to impacting.As mentioned above, the impact resistance of bearing unit 660 is poor.

In addition, as the another kind of bearing unit of rotatably mounted running shaft, the example that has the open 2000-352414 communique of Japanese patent of invention to be put down in writing.The bearing unit 680 of this communique record as shown in Figure 3, be the bearing unit of rotatably mounted running shaft 681, the bearing housing 685 that has the radial bearing 682 that on the peripheral direction of running shaft 681, supports, the thrust-bearing 683 that on thrust direction, supports and hold this radial bearing 682 and thrust-bearing 683.

In this bearing unit 680, radial bearing 682 is with constituted Hydrodynamic bearing as the lubricant oil that is filled in the viscous fluid in the bearing housing 685, be formed with the dynamic pressure generation groove 684 that is intended to produce dynamic pressure on the inner peripheral surface that running shaft 681 passes.

The outer circumferential face of radial bearing 682 be provided with for when inserting the axle part to the internal diameter position of bearing body with the axial ventilation path 686 of the flute profile of air discharging and ventilation path 687 radially.

As shown in Figure 3, the bearing housing 685 that holds the radial bearing 682 of supporting rotating shaft 681 forms the cylindric of the end, fences up so that be the lateral parts and the underside portion of the radial bearing 682 of cylindric formation.

Above bearing housing 685, in the opened portion, be provided with into the elastomer 688 of confined state rivet clasp on internal diameter.

For bearing unit 680, running shaft 681 is inserted in the bearing housing 685 of the flexible body 688 of rivet clasp.At this moment, the air in the bearing housing 685 by axial ventilation path 686 and radially ventilation path 687 outside bearing housing 685, discharge, therefore, the insertion operation of running shaft 681 can be carried out swimmingly.

Bearing unit shown in Figure 3 680 since be with bearing housing 685 and 688 two parts of elastomer with the structure that fences up around the bearing body, therefore, exist the possibility that lubricant oil oozes out from the joining portion between this bearing housing 685 and the elastomer 688.

Summary of the invention

The purpose of this invention is to provide a kind of bearing unit of the existing problem of bearing unit that solves existing scheme and the rotating driving device that uses this bearing unit.

What another object of the present invention provided a kind of small-sized and long service life has very the bearing unit of high reliability and a rotating driving device that uses this bearing unit.

Another object of the present invention provides a kind of axle that can accomplish to prevent that bearing from supporting and comes off, can prevent the bearing unit of oil leak and the rotating driving device that uses this bearing unit.

For this reason, another object of the present invention provides a kind of preventing because axle and the two relative rotation of bearing housing, the bearing housing internal pressure reduces and causes that residual air expands, thereby the lubricated wet goods viscous fluid that causes being filled in bearing housing inside is pressed against the leakage phenomenon outside the bearing unit, can obtain good lubricated bearing unit and use the rotation of this bearing unit to drive dress.

Another object of the present invention provides a kind of lubricated wet goods viscous fluid and is difficult for bearing unit that splashes because of reasons such as impacts and the rotating driving device that uses this bearing unit.

Another object of the present invention provides a kind of bearing unit that lubricated wet goods viscous fluid oozes out from the bearing housing that bearing is fenced up and rotating driving device that uses this bearing unit of preventing.

The invention belongs to a kind of bearing unit of rotatably mounted axle, have: reserve the space of the end that is used for making axle stretching out to the outside and be the holding member of seamless shape; Be configured in the inside of holding member, the bearing of rotatably mounted axle on centripetal direction; Be installed on the axle, prevent the axle fall-out preventing component that axle comes off on thrust direction by connecting with bearing; And the inside that is configured in holding member, be used for around the axle fall-out preventing component, guaranteeing that the space in space forms parts.

Bearing unit involved in the present invention is configured in the inside of holding member.This bearing unit is rotatably mounted axle on centripetal direction.The fall-out preventing component of axle is installed on the axle, by coming off along thrust direction with the inconsistent axle that prevents of bearing.The space forms the inside of component configuration at holding member.It is the parts that are used for guaranteeing the space around the axle fall-out preventing component that this space forms parts.So, by being set, the space forms parts, the axle fall-out preventing component can be arranged on the inside of the holding member of bearing unit, thereby volume is less.Its result can realize the miniaturization of the rotating driving devices such as motor of installation shaft bearing unit.As bearing unit, because of being provided with a fall-out preventing component, come off so can prevent the axle that is in assembled state, therefore, in the time of on being installed to rotating driving device, have good operation convenience.

Holding member is to reserve to be used for making the end of axle to be seamless shape formation to outstanding space, outside, therefore, oil leak can not take place, can constitute the very bearing unit of high reliability that has of small-sized and long service life.

Make a fall-out preventing component integrally formed, just can reduce number of components and parts with axle.

In addition, holding member is formed by macromolecular material, to have on the outstanding position, the outside of holding member with axle between the space of formation.

In bearing unit involved in the present invention, the space forms parts and is formed by macromolecular material, the thrust-bearing of double as end of rotatably mounted axle on thrust direction, and the end of axle is spherical, thrust-bearing is a trunnion bearing.

Like this, the space forms parts not only can guarantee the space around the axle fall-out preventing component, and can realize the minimizing and the miniaturization of amount of parts with the end of form rotatably mounted axle on thrust direction of trunnion bearing.

The outer circumferential face of bearing unit axle involved in the present invention or the inner peripheral surface of bearing are provided with dynamic pressure and produce groove, thereby can produce dynamic pressure by the rotation of axle.

The bearing unit involved in the present invention also surface of surperficial or relative with the axle fall-out preventing component space formation parts of axle fall-out preventing component is provided with dynamic pressure generation groove, therefore, can produce dynamic pressure along with the rotation of axle.

In bearing unit involved in the present invention, axle and space form parts and are made of conductive member, space formation parts from holding member to exposing outside.Like this, can make static form parts by the space and externally go into ground from beam warp.

In addition, the invention belongs to a kind of rotating driving device, have: reserve the space of the end that is used for making axle stretching out to the outside and be the holding member of seamless shape with bearing unit of rotatably mounted axle; Be configured in the inside of holding member, the bearing of rotatably mounted axle on centripetal direction; Be installed on the axle, by with bearing inconsistent prevent the axle on thrust direction, come off the axle fall-out preventing component; And the inside that is configured in holding member, be used for around the axle fall-out preventing component, guaranteeing that the space in space forms parts.

Bearing is configured in the inside of holding member.This bearing is rotatably mounted axle on centripetal direction.The axle fall-out preventing component is installed on the axle, by coming off on thrust direction with the inconsistent axle that prevents of bearing.

The space forms the inside of component configuration at holding member.It is in order to guarantee the parts in space around the axle fall-out preventing component that this space forms parts.Form parts by the space is set, the axle fall-out preventing component can be arranged on the inside of the holding member of bearing unit, thereby can realize the miniaturization of bearing unit, the feasible miniaturization that the rotating driving devices such as motor of this bearing unit are installed becomes possibility.

Another kind of bearing unit involved in the present invention except the space forms parts, also have with axle between the seal oil that disposes across the space with parts and the bearing housing parts that keep the resin manufacture of these parts and gear mechanism from periphery.

According to bearing unit involved in the present invention, sealing is kept with parts from periphery by bearing housing with resin manufacture, can realize making the jointless structure of the two combination seamlessly.Therefore, do not need sealing is sealed with binder etc. with the gap between parts and the bearing housing.In addition, with the pore volume between parts and the axle,, therefore, can make the discreteness in space be reduced to enough low about sealing owing to machining accuracy that can be by these parts and forming accuracy etc. are guaranteed.

Another kind of bearing unit involved in the present invention has: axle; Radial bearing at circumferential upper support axle; The thrust-bearing that a end on the thrust direction of axle is supported; The space that is arranged on the outside of radial bearing and thrust-bearing forms parts; The space form component configuration within it portion, have a bearing housing of wearing the structure that is sealed the axis hole except axle is passed; Be filled in the viscous fluid in the bearing housing; And be formed at the path that the space forms between parts and the radial bearing, the end on the thrust direction of axle outstanding from radial bearing is communicated with the other end.

In a kind of like this bearing unit involved in the present invention, as be sealed in an end the open side of non-axle in the bearing housing, from radial bearing on the thrust direction of outstanding axle, with the two is connected by communication paths as being provided with the other end axle open sides of wearing axis hole, from radial bearing on the outstanding thrust direction.Therefore, in that axle is relative with bearing housing when rotating,, therefore, can suppress the reduction of non-open sides pressure because non-axle open sides is communicated with the axle open sides.Owing to can suppress the reduction of non-axle open sides pressure, thereby can suppress the expansion of residual air in the bearing housing, can not take place that lubricated wet goods viscous fluid is squeezed and the situation of leaking.

In another kind of bearing unit involved in the present invention, though non-axle open sides is connected with an axle open sides, having only wherein as the other end on the outstanding thrust direction from radial bearing of the open side of non-axle is only by minimum gap of wearing axis hole and external communications.That is, communication paths is formed in the bearing housing, and bearing housing has the structure that is sealed except wearing axis hole, therefore, can prevent that lubricated wet goods viscous fluid from splashing because of impact, can also prevent that viscous fluid from oozing out.

About other purpose of the present invention, advantage that the present invention had etc., can further understand by in conjunction with the accompanying drawings concrete mode of execution below.

Description of drawings

Fig. 1 is a sectional view of showing existing bearing unit.

Fig. 2 is a sectional view of showing existing another kind of bearing unit.

Fig. 3 is a sectional view of showing existing another bearing unit.

Fig. 4 is a stereogram that example is showed to the electronic equipment that uses bearing unit involved in the present invention.

Fig. 5 is that V-V that employed fan motor in the related electronic equipment of Fig. 4 is showed is to sectional view.

Fig. 6 is a stereogram of showing an example of fan motor.

Fig. 7 shows the rotor of fan motor and the sectional view of stator.

Fig. 8 is the sectional view of the bearing unit of use in the exploded view 7.

Fig. 9 A～Fig. 9 C is the sectional view that the number of assembling steps of bearing unit shown in Figure 8 is showed.

Figure 10 is the sectional view that another example of bearing unit involved in the present invention is showed.

Figure 11 is the sectional view that another example of bearing unit involved in the present invention is showed.

Figure 12 A, Figure 12 B are the sectional views that another example of bearing unit involved in the present invention is showed.

Figure 13 A～Figure 13 D is the sectional view of the manufacture method of bearing unit shown in Figure 12 being showed according to the order of operation.

Figure 14 is the sectional view that another example of bearing unit involved in the present invention is showed.

Figure 15 is the sectional view that another example of bearing unit involved in the present invention is showed.

Figure 16 is the sectional view that the structure example summary of the rotating driving device that uses bearing unit involved in the present invention is showed.

Figure 17 is the sectional view of just being showed as the example of the motor of the rotating driving device that uses bearing unit involved in the present invention.

Figure 18 is that Y-Y ' that bearing unit shown in Figure 19 is showed is to sectional view.

Figure 19 is that the X-X ' of Figure 18 is to sectional view.

Figure 20 is that formed dynamic pressure produces the stereogram that groove is showed on the inner peripheral surface to radial bearing.

Figure 21 is the stereogram that the shape that is formed at the communication paths between space formation parts and the radial bearing is showed.

Figure 22 is the worm's eye view that the 2nd groove as communication paths on the underside portion that is formed at radial bearing is showed.

Figure 23 is the stereogram that the another kind of shape that is formed at the communication paths between space formation parts and the radial bearing is showed.

Figure 24 is the plan view that the 2nd groove as communication paths on the bottom surface that is arranged on space formation parts is showed.

Figure 25 be to by the outer circumferential face of running shaft be arranged on the sectional view that space that the inner peripheral surface of wearing axis hole on the bearing housing forms is showed.

Figure 26 is the accompanying drawing that the wicking of convection cell describes.

Figure 27 is to entering the outer circumferential face that is formed at running shaft and wearing the transverse sectional view that the state of the lubricant oil in the space between the inner peripheral surface of axis hole is showed.

Figure 28 is used for longitudinal sectional view that difference to the suction pressure at the different-diameter place of tapered portion set on the running shaft describes, that the space between the outer circumferential face that is formed at running shaft and the inner peripheral surface of wearing axis hole is showed.

Figure 29 is to entering the outer circumferential face that is formed at running shaft and wearing the longitudinal sectional view that air is sneaked in the lubricant oil in the space between the inner peripheral surface of axis hole state is showed.

Figure 30 is the transverse sectional view that the state that enters the outer circumferential face that is formed at running shaft and wear lubricant oil in the space between the inner peripheral surface of axis hole when interrupting is showed.

Figure 31 is the longitudinal sectional view that running shaft is showed with respect to the state of wearing axis hole existence off-centre set on the bearing housing.

Figure 32 wears the sectional view that axis hole exists the state that enters the lubricant oil in the space when eccentric to show to running shaft with respect to set on the bearing housing.

Figure 33 wears the sectional view that another example that axis hole is provided with bearing unit tapered portion, that the present invention's the 3rd mode of execution is related describes to set on the bearing housing.

Figure 34 is the accompanying drawing that operation among the manufacturing process of bearing unit shown in Figure 19, that temporarily assemble is described.

Figure 35 be among the manufacturing process of bearing unit involved in the present invention, the accompanying drawing that describes of the operation of packet shaping mode forming axis bearing sleeve in addition.

Figure 36 be among the manufacturing process of bearing unit involved in the present invention, running shaft is inserted the accompanying drawing that the operation in the bearing housing describes.

Figure 37 is the accompanying drawing that operation among the manufacturing process of bearing unit involved in the present invention, packing lubrication oil is described.

Figure 38 is the sectional view that another example of bearing unit involved in the present invention is showed.

Embodiment

Below, to preferred implementation of the present invention in conjunction with the accompanying drawings.

Bearing unit involved in the present invention can be used for being installed in the motor in the notebook computer 1 shown in Figure 4.

As shown in Figure 4, computer 1 has display unit 2 and main frame 3, and display unit 2 is connected on the main frame 3 by joint 4 and can rotates.Main frame 3 has keyboard 5 and housing 12.Be provided with sink 10 in the housing 12.

Fig. 5 be the V-V of housing 12 of Fig. 4 to sectional view, Fig. 6 is the stereogram that the sinks 10 that are arranged in the housing 12 shown in Figure 5 are showed.

As shown in Figure 5, accommodate sink 10 in the housing 12.This sink 10 has structure shown in Figure 6.Sink 10 also is known as cooling unit, has base 20, motor 30, the fan 34 as solid of rotation, fan drum 36, radiator 38 that metal is made.

The one side 21 of base 20 has the 1st attachment face the 50, the 2nd attachment face 52 and the 3rd attachment face 54.See that on the whole the 1st attachment face the 50, the 2nd attachment face 52 and the 3rd attachment face 54 have formed the face that approximately is the L type, on the 1st attachment face 50, the centre is serving as a contrast heat-conducting plate 44 heater element 40 is being installed.This heater element 40 for example is CPU (central processing unit (CPU)), produces the element of heat when being energising work.

Be fixed with fan drum 36 and motor 30 on the 2nd attachment face 52.Accommodate fan 34 and motor 30 in the inside of fan drum 36.Fan drum 36 has circular hole 48.As shown in Figure 5, this circular hole 48 is formed on the position relative with the following hole 60 of housing 12.Fan drum 36 has the hole 37 of supplying with cooling air in radiator 38 1 sides as the object that is cooled.

Be fixed with radiator 38 on the 3rd attachment face 54.This radiator 38 for example is the radiator of bellows-shaped or fin shape, by the metal with good thermal diffusivity for example aluminium make.Base 20 and fan drum 36 can have the aluminium or the iron of the metal of good thermal diffusivity by conduct.Be provided with the hole 70 that usefulness is installed at the position of necessity of base 20, base 20 be by these mounting holes 70 by screw on the projection 72 that is arranged on housing 12 inner faces.

As shown in Figure 5 and Figure 6, radiator 38 is configured on the 76 corresponding positions, hole with the side of housing 12.So along with motor 30 work, the R direction of fan 34 in Fig. 6 rotated continuously, thus with the air of housing 12 inside from the hole 60 and hole 48 along the direction of arrow D1, D2, D3 from the hole 76 of side to outside drain.At this moment, the heat that heater element 40 is produced is delivered on the attachment face 54 by the

attachment face

50,52 of base 20, and therefore, the heat of heater element 40 will be delivered on the radiator 38.Because the air-flow that fan 34 rotations are produced flows along the direction of arrow D1, D2, D3, thereby the heat that is delivered on the radiator 38 can be discharged into the outside by the hole 76 of housing side.

Fig. 7 illustrates the example of the cross-sectional configuration of motor 30 shown in Figure 6.This motor 30 has rotor 80 and stator 84.

Accommodate this motor 30 and fan 34 in the fan drum 36, stator 84 is arranged on summit portion 36A one side of fan drum 36 integratedly.Stator 84 has stator yoke iron 88 and bearing unit 90, coil 164 and iron core 160.

Stator yoke iron 88 both can be made of one with the summit portion 36A of fan drum 36, also can be independent parts, was for example made by iron or stainless steel.The bearing housing 120 of bearing unit 90 is by being pressed into or bonding or this dual mode is fixed in the retainer 92 of stator yoke iron 88.Retainer 92 is cylindric parts.

Bearing unit 90 has radial bearing 130 substantially, the space forms parts 113, holding member 120 and lubricant oil 150.

Fig. 8 illustrates the structure amplification of bearing unit shown in Figure 7 90.

Below, in conjunction with Fig. 8 the structure of bearing unit 90 is described in detail.

Axle 100 is so-called I fonts, also is known as linear.This axle 100 is for example made by stainless steel.This axle 100 has the end of exposing 160, inner end 161, tapered portion 100A.Expose end 160 with the axle peripheral part 162 each outside dimension can be identical.Tapered portion 100A is in the tapered part that exposes between end 160 and the axle peripheral part 162.This tapered portion 100A attenuates to exposing end 160 1 sides from axle peripheral part 162.The space S that exposes end 160 and be self-sustaining parts 120 is to the part that exposes outside.This tapered portion 100A be positioned at the corresponding position of S, this space on.

Secondly, the radial bearing 130 among Fig. 8 is the cylindrical bearings that are made of sintering metal or Hydrodynamic bearing.Radial bearing 130 has two dynamic pressures generation grooves 190,190 on the side face within it.Dynamic pressure produces groove the 190, the 190th, and devices spaced apart is provided with.A dynamic pressure produces groove 190 and is positioned near on the position of space S.Another dynamic pressure produces groove 190 and is positioned at inner end 161 1 sides.Dynamic pressure produces groove 190,190, for example can adopt lambdoid groove.This radial bearing 130 makes it rotatably to support to axle 100 on centripetal direction.

Axle fall-out preventing component 115 among Fig. 8 is metal partss such as macromolecular material parts such as nylon or E type ring.Axle fall-out preventing component 115 is fixed in the recess 169 of inner end 161 1 sides that are arranged on axle 100 by the cast setting mode.This fall-out preventing component 115 is to prevent axle 100 parts that come off to the E direction along centre line C L from radial bearing 130.

It is in order to ensure the parts that form the space around axle fall-out preventing component 115 that space among Fig. 8 forms parts 113.The space forms parts 113 and is configured in the holding member 120.It is to have the cage type parts that are about the U glyph shape from section that the space forms parts 113.The space forms parts 113 and is for example made by metal partss such as macromolecular material such as nylon or brass.

Holding member 120 among Fig. 8 is to be used for above-mentioned radial bearing 130, axle 100, axle fall-out preventing component 115 and space are formed parts 113 are enclosed in the inside with seamless state parts.Holding member 120 is called bearing housing again, only is provided with a space S who is provided with accordingly with tapered portion 100A.Holding member 120 is for example made by nylon, LCP (liquid-crystalline polymer), Te Fulong macromolecular materials such as (TM trade mark).

Axle peripheral part 162, axle fall-out preventing component 115, space at radial bearing 130, axle 100 form between the parts 113 and are filled with lubricant oil.

Bearing unit 90 shown in Figure 8 exposes near the end 160, is disposed radially very little space S axle 100.Be held parts 120 and be the structure that seamless state fences up owing to make periphery outside the S of this space, therefore, lubricant oil can not leak into the outside of holding member 120, has very high reliability.

As bearing unit 90, be provided with a fall-out preventing component 115 in order to prevent axle 100 from coming off in inside, therefore, when the motor 30 with bearing unit 90 being carried out the craft processing, can arbitrarily operate.

The axle 100 of facing space S is provided with tapered portion 100A.This tapered portion 100A and space S have constituted the surface tension sealing.Surface tension sealing is the lubricant oil retaining mechanism that has utilized wicking, with regard to bearing unit 90, can with lubricant oil to the direction of gap turn narrow, be that the internal direction of bearing unit 90 sucks, thereby lubricant oil can be to external leakage.That is, the principle of surface tension sealing is to form pressure gradient by tapered portion 100A is set, and lubricant oil is held, as long as with tapered portion 100A or be arranged on the axle 100 or be arranged on the holding member 120.

Here, the necessity that a fall-out preventing component 115 is set is described.

For the motor 30 that bearing unit involved in the present invention 90 is installed shown in Figure 7, do not prevent that the rotor 80 that comprises axle 100 from coming off if do not take measures, then when motor 30 was subjected to impacting, rotor 80 can come off, therefore, Drop-proof is absolutely necessary for shock resistance.

In addition, even if the spindle motor that CD is used also needs to take the Drop-proof measure to guarantee that rotor 80 can not come off when picking and placeing CD.

In the prior art, the fall-out preventing component of requisite rotor part or be arranged on the outside of bearing unit perhaps makes the holding member of bearing unit be formed by a plurality of component-assembled so that attach it to bearing inside; And the former exists and causes the shortcoming that motor boundary dimension is big, assembling is complicated, the latter then to exist holding member having the problem that leak easily at joining portion, lubricant oil.

In the bearing unit 90 involved in the present invention, its fall-out preventing component 115 is configured in the inside of bearing unit 90, and holding member 120 is a jointless structure.Therefore, bearing unit 90 becomes and a kind ofly is assembled in the motor 30 easily, is convenient to handle and lubricant oil can not leak, can guarantee the very bearing unit of high reliability that has in very long working life.

Fig. 9 A～Fig. 9 C illustrates the example of the number of assembling steps of bearing unit 90 shown in Figure 8.

At first, shown in Fig. 9 A, the axle 100 that a fall-out preventing component 115 is installed is inserted in the radial bearing 130.

Secondly, shown in Fig. 9 B, the space is formed parts 113 be installed on the radial bearing 130.Afterwards, shown in Fig. 9 C, by formation holding members 120 such as outer packet shapings.

Afterwards, soak with vacuum and mode packing lubrication oil such as to contain and the amount of lubricant oil is adjusted, just can obtain bearing unit 90.

Form parts 113 by the space is set, even if holding member 120 is to be formed by the outer packet shaping of resin, also can guarantee to form the space around axle fall-out preventing component 115, axle 100 is supported rotating freely ground with axle fall-out preventing component 115.

In example shown in Figure 8, the thrust-bearing that the inner bottom surface double as that the space forms parts 113 makes it rotatably to support to the inner end 161 of axle 100 on thrust direction.These space formation parts 113 support inner end 161 in so-called pivot mode and enable rotation.

Bearing unit involved in the present invention also can constitute as illustrated in fig. 10.Bearing unit 490 shown in Figure 10 has axle 400, axle fall-out preventing component 415, radial bearing 430, space formation parts 413 and holding member 420.

Bearing unit 490 shown in Figure 10 is that its discoideus axle fall-out preventing component 415 is integrally formed with it on the inner end 461 of axle 400.That is, axle 400 constitutes the axle that section configuration is about T shape with axle fall-out preventing component 415.

On face of axle fall-out preventing component 415 and another face, be formed with dynamic pressure respectively and produce groove 428.These dynamic pressures produce grooves 428 and form in the space in the space of parts 413 and to produce dynamic pressure when axle fall-out preventing component 415 made it rotatably to support.

In order to form the space with good precision around axle fall-out preventing component 415, the space forms parts 413 and is for example made by resins such as metal such as brass or stainless steel or LCP, polyamide, polyimide.Holding member 420 is for example made by LCP, nylon, polyamide, polyimide, Te Fulong resins such as (TM trade mark).Holding member 420 is made into and is seamless structure except the S of space.

As mentioned above, axle fall-out preventing component 415 is to prevent axle 400 parts that come off along the E direction from radial bearing 430.And this fall-out preventing component 415 plays a part not only to prevent that axle from coming off, and also plays a part to be provided with the Hydrodynamic bearing type thrust-bearing mechanism that dynamic pressure produces groove 428.

Dynamic pressure produces groove 480 and can be formed on the inner peripheral surface of radial bearing 430.Dynamic pressure generation groove 480 is not limited on the inner peripheral surface of radial bearing 430 and forms, and also can form on the axle outer circumferential face 462 of axle 400.

Dynamic pressure produces groove 428 and not only can form on a face of axle fall-out preventing component 415 and another face, also forms on the interior edge face 414 that can form parts 413 in the inner end 431 and the space of radial bearing 430.

The axle fall-out preventing component is made of stainless steel etc., both can be entirely one with axle 400, also can be used as independent parts and makes in advance.Axle 400 is made by stainless steel etc., but also can by LCP, polyamide, polyimide, PC (polycarbonate (PC)) resin of etc.ing in addition the packet shaping mode make.

Bearing unit 490 shown in Figure 10 can be made the structure that is hydraulic bearing on centripetal direction and the thrust direction easily.Therefore, bearing unit 490 shown in Figure 10 is compared with bearing unit 90 shown in Figure 8, and its longer service life, reliability are higher.

Figure 11 illustrates another example of bearing unit involved in the present invention.

Bearing unit 590 shown in Figure 11 has and the identical substantially structure of bearing unit 490 shown in Figure 10.Therefore, in bearing unit shown in Figure 11 590, the part identical with bearing unit shown in Figure 10 490 given identical numbering, omits its detailed description.

Bearing unit 590 shown in Figure 11 is the shape of holding member 520 and the effect of axle fall-out preventing component 415 and space formation parts 413 with the difference of bearing unit 490 shown in Figure 10.

Holding member 520 has space S and other opening portion 530.The space form parts 413 from this opening portion 530 to exposing outside.

Axle 400 is for example made by conductive materials such as stainless steels.The space forms parts 413 and is made by conductive materials such as brass or stainless steels.And, the space form parts 413 from opening portion 530 to exposing outside.

So, the static that motor shown in Figure 11 produces when work can form parts 413 via axle 400, axle fall-out preventing component 415 and space and externally go into ground shown in the arrow E among the figure.

Therefore, be installed in occasion in the such device of hard disk drive at bearing unit involved in the present invention, even produce for example static of 30V, this static also can be gone into the path, ground and outwards discharges by above-mentioned.Therefore, can prevent that employed magnetic head takes place because of the phenomenon that this static is damaged in the hard disk drive.

In this occasion, lubricant oil is filled in the space and forms between the axle outer circumferential face 462 and radial bearing 430 of parts 413, axle fall-out preventing component 415, axle 400.If the lubricant oil of this filling has electric conductivity, then can improve discharge performance.

Fig. 8, Figure 10 and bearing unit 90,490,590 shown in Figure 11 are not only applicable to motor shown in Figure 5 30, but also can use as the bearing unit that makes the information recording carrier rotation in the information recording/reproducing apparatus such as above-mentioned hard disk drive.

Bearing unit involved in the present invention, form parts owing to be provided with the space, thereby the axle fall-out preventing component can be arranged on bearing unit inside, so volume is little, can make the motor of installation shaft bearing unit realize miniaturization, and axle can not come off when assembling, therefore, become the manual bearing unit very easily that deals with, in addition, because a side that goes out in aixs cylinder only leaves very little space, and seamless holding member is set around, therefore, become that lubricant oil can not leak, long service life, bearing unit that reliability is very high.

And then the rotating driving devices such as motor that bearing unit involved in the present invention is installed can be realized miniaturization, and, because need be, thereby can obtain that operation is simplified, cheap rotating driving device at motor outer installment fall-out preventing component.

Below, another example of bearing unit involved in the present invention is described in conjunction with Figure 12 and Figure 13.

In the example below, as the gear mechanism that axle or running shaft are supported, be provided with radial bearing mechanism and thrust-bearing mechanism, for the thrust-bearing mechanism of shaft end, that enumerates is to use example that pivot (pivot) profile shaft holds and the example that uses Hydrodynamic bearing.

Figure 12 A is the sectional view that the example of the bearing unit that uses radial bearing mechanism and thrust-bearing mechanism is showed.In this example, the end of axle is processed to spherical portion, has constituted thrust-bearing mechanism by this part of parts carry that forms with macromolecular material.

Bearing unit 201 has by materials such as stainless steel and other metal materials or resin materials and is axle 202 that the pole shape forms and to this 202 gear mechanism that supports 203.That is,, be provided with and entad bear the radial bearing mechanism 204 of load and the thrust-bearing mechanism 205 of bearing thrust load as gear mechanism 203.

The radial bearing mechanism 204 that axle 202 is made it to support with rotating freely on centripetal direction uses sintered metal bearing or Hydrodynamic bearing etc.As an example, describe with regard to the example that uses Hydrodynamic bearing.This bearing for example has the structure of the groove that formation generation dynamic pressure is used on copper class or copper iron class sintering metal, utilizes the peculiar cellular structure of sintering metal to store lubricant oil.The groove that the generation dynamic pressure is used is to be made of V-shaped so-called man type chute in this example.What use in this example is, in the interior perimembranous that is radial bearing cylindraceous mechanism 204, two groups of dynamic pressures produce

groove

204a, 204a ..., and 204b, 204b ... carrying in the Hydrodynamic bearing that upwards forms in week of the direction of axle rotation respectively, but also can be on the side face of axle 202, to form dynamic pressure to produce with groove.In addition, in the present invention, be not limited in Hydrodynamic bearing, can also be implemented to use other forms such as metal bearing.

Be formed with the engagement groove 202a of ring-type on the position of the close front end of axle 202, the fall-out preventing component 206 of ring-type is installed on wherein.Fall-out preventing component 206 is for example formed or uses metal partss such as E type ring by nylon macromolecular materials such as (straight chain fatty polyamides), the occasion that changes have external force to act on vertically because of reasons such as vibrations or air pressure etc., the backstop performance function that comes off as preventing axle 202 from moving on the heart line direction therein.

Be provided with parts with metals such as nylon, polyimide, liquid-crystalline polymer macromolecular materials such as (LCP) or brass formation (below be called " space formation parts ") 207 around the fall-out preventing component 206.It is will be fixed on the angle that is rotated together on the axle 202 from fall-out preventing component 206 to consider that this space forms parts 207, is provided with in order to form predetermined space around fall-out preventing component 206.

In this example, the space of resin manufacture forms parts 207 and forms the tubular that the end is arranged with recess 207a, and the end face of axle 202 is spherical shape and carries out contacting with the flat bottom surface of recess 207a.As mentioned above, for the thrust-bearing mechanism 205 of on thrust direction, axle 202 being supported, if adopt and for example on axle head 202b, form convex surface, make it to form the form that parts 207 contact with the space, then do not need to be used for supporting the support unit of axle head.This is because the space forms the cause of parts 207 double as support units.In addition, be not limited in this example, also can make it to contact and wait other form to be implemented with axle head to be integrally formed into teat or support on forming parts in the space with it.

Space shown in this example forms on the parts 207 and is formed with step 207b.Step has constituted can make radial bearing mechanism 204 parts be embedded in wherein embedding recess.Its reason will describe in the manufacture method of back.

Seal oil is with parts (below be called " Sealing ") the 208th, with form very little space G within it between side face 208a and the axle 202, promptly in exposed junction one side of axle 202 interstitial state configuration diametrically, for example macromolecular material such as nylon or teflon or metal are cylindric formation with resin material.On sealing part 208, be formed with step 208b.This step has constituted can make radial bearing mechanism 204 parts be embedded in wherein embedding recess.Its reason will describe in the manufacture method of back.A part 209 that is filled in the lubricant oil of device inside is present among the G of space shown in Figure 12 B.In addition, formed indentation 208c is that formed teat forms accordingly on the end with radial bearing mechanism 204 on the Sealing 208, this teat be on being used for discerning axially towards sign.

Bearing housing parts or holding member 210 are the parts that Sealing 208 and radial bearing mechanism 204 kept from periphery, form with macromolecular materials such as resin material, for example polyimide, polyamide, nylon, LCP.In this example, bearing housing parts 210 have and make radial bearing mechanism 204 and space form the effect that parts 207 and Sealing 208 seamlessly fully seamlessly engage.Therefore, can prevent oil leak.

In addition, in this example, leak the measure of having taked from axle 202 to the part that exposes outside for preventing lubricant oil.

Promptly, shown in the enlarged view of Figure 12 B, near the outside exposed portions serve of axle 202, and the part that forms space G between the Sealing 208 is tapered portion 202c, be with along axle 202 to internal direction, promptly form along with becoming big shape gradually near the diameters of axle to radial bearing mechanism 204.

Space G is formed at towards the inner diameter of axle and becomes big tapered portion 202c gradually and with it between in opposite directions the inner peripheral surface 208a of Sealing 208, therefore, past more device internal voids amount diminishes gradually.Be " p " if establish the suction pressure that wicking produces, " p=2 γ cos θ/c " (wherein, γ: lubricated oil surface tension, θ: the wrapping angle of lubricant oil, c: relation pore volume), p and pore volume c be inversely proportional to (p ∝ 1/c) is then arranged.Therefore, pore volume c is more little, and the suction pressure that is produced is big more, lubricant oil 209 can be sucked to the little internal direction of pore volume c, thereby lubricant oil can not move and spill to the outside.In addition, when the diameter of axle one timing, if exist eccentric then looking up from axle to exist the little part of the pore volume part big with pore volume, lubricant oil will be displaced to the little part place of pore volume; And on axle when being formed with tapered portion 202c, pore volume changes vertically, has gapped equal part in the cutting plane that is ellipsoid that tilts with respect to axle, therefore, can reduce the skew of the lubricant oil that off-centre causes.In addition, the action of centrifugal force in the time of can also obtaining the axle rotation is difficult to make lubricating oil splash to arrive outside sealing effect.

In addition, can list, locate to be coated with the method for interfacial agent on the exposed division of axle 202 and the surface of Sealing 208 etc. in order to prevent oil leak.By the coating interfacial agent, can make with the wrapping angle θ of lubricant oil increases, its result, and suction pressure p weakens.That is, reduce outside suction pressure p, can make inner suction pressure p improve relatively, therefore, can prevent the leakage of lubricant oil and move.

Below, in conjunction with Figure 13 A～Figure 13 D the manufacture method of bearing means involved in the present invention is described.This figure is the process chart of an one example being showed with regard to the assembling procedure of bearing unit 201, can make bearing unit according to following operation.

(1) axle inserts operation

(2) space forms the installation procedure of parts and Sealing

(3) the bearing housing parts form operation

(4) filling of lubricant oil and oil mass are adjusted operation

At first, in the operation shown in Figure 13 A (1), the axle 202 that fall-out preventing component 206 is installed is inserted in the radial bearing mechanism 204.Afterwards, in the operation shown in Figure 13 B (2), the space is formed parts 207 and Sealing 208 is installed in the radial bearing mechanism 204.Promptly, the step 208b that the space is formed the step 207b of parts 207 and Sealing 208 be embedded in outward radial bearing mechanism 204 axially on the outer periphery of each end on, make radial bearing mechanism 204 be in the part and be embedded in the space and form state in each recess of parts 207 and Sealing 208.

When this operation finished, axle 202 had been in the supporting that obtains gear mechanism 203 and the state that can rotate.

Secondly, in the operation shown in Figure 13 C (3), macromolecular materials such as use nylon form bearing housing parts 210 by outer packet shaping.

Afterwards, in the operation shown in Figure 13 D (4), lubricant oil is soaked the mode of containing by vacuum be filled into device inside, and adjust oil mass.For example will under set temperature conditions,, thermal expansion remove because of flowing to outside unnecessary oil mass.

In the bearing unit of as above making 201, by carrying out the outer packet shaping of bearing housing parts 210, can make radial bearing mechanism 204, space formation parts 207, Sealing 208 be seamless state and engage, therefore, there is not the gap between parts and the parts, can prevents the leakage of lubricant oil fully.In addition, unlike prior art, need the filler of implementing on the joining portion be managed, can make the management of operation obtain simplifying.

Though in the operation shown in Figure 13 B (2), also can carry out the shaping of Sealing 208, but the little occasion of pore volume between Sealing and axle, preferably as mentioned above, adopt and to make Sealing 208 in advance and again it is installed in method in the radial bearing mechanism 204.Its reason is in order to guarantee that there are enough precision in the space.For example at pore volume c during greater than permitted value, it is too small that the suction pressure p that wicking produced can become, and therefore, pore volume exists the upper limit.Therefore, in the occasion that is necessary to increase oil mass, need to increase space G length in the axial direction.Its result has to that it is very thin and axially go up long shape that the mould part that is used for forming space G is made wall thickness, causes the technical difficulty that becomes of being manufactured on of mould.And if do not reach enough forming accuracies, then the discreteness of pore volume will increase.For this reason, if make Sealing before in the operation (2) shown in Figure 13 B, reach enough precision just can guarantee it, the precision in space can be guaranteed.Can in addition, impact resistance be and square being inversely proportional to of pore volume C, and therefore, reduces pore volume and reduces its discreteness, be related to prevent that lubricant oil from splashing because of impact.But,, then should be noted that the problem that raises temperature the thermal expansion meeting that causes causes the variable quantity of pasta position to increase if pore volume is too small.

The space formation parts that constitute bearing unit are not to be only limited to the synthetic resin material, can form with metallic material yet.This example is shown in Figure 14.

The bearing unit 201A shown in Figure 14 and the difference of above-mentioned bearing unit 201 are as described below.In the following description, give identical numbering, it is described in detail omit for the part identical with bearing unit 201.

Promptly, bearing unit 201A shown in Figure 14 is that its space formation parts 207A is for example formed by stainless steel, brass, pressure processing material, agglomerated material etc., the 205A of thrust-bearing mechanism has the thrust bearing part 211 of the processed glomerate axle head 202b of supporting, and this thrust bearing part 211 is to be configured in the space to form among the recess 207a of parts 207A and install.In addition, thrust bearing part 211 is with low-friction materials such as resin material such as nylon, polyimide, polyamide, liquid-crystalline polymer or rubidiums, forms with the space that parts 207A split forms.

In this bearing unit 201A, the space forms parts 207A metal manufacturing, therefore, from the consideration that increases the service life, is provided with the thrust bearing part 211 that uses resin material or low-friction material.In addition,, the increase space makes the structure of withstand high temperatures but forming the rigidity of parts 207A, can make forming in outsourcing forming processes forming process, bearing housing parts 210 of carrying out after the parts 207A that the injection temperature of resin and pressure condition etc. become loose as installing space.That is, in this example,,, overall cost is reduced owing to do not select resin material, molding condition to become loose though the anxiety that thrust bearing part 211 has the cost increase is set.

Below, another example of bearing unit involved in the present invention is described in conjunction with Figure 15.The difference of bearing unit 201 is shown in the bearing unit 201B that this is routine and Figure 12 A, and is T-shaped from the side shaft end of seeing over, and is the thrust-bearing mechanism that utilizes the fall-out preventing component of axle to constitute to be made of Hydrodynamic bearing.Therefore, in the following description, give identical numbering, it is described in detail omit for the part identical with bearing unit 201.

In bearing unit 201B shown in Figure 15, the fall-out preventing component 212 that is located at axle 202 front ends is and has the discoideus of set thickness, is formed by metal such as brass or stainless steel or macromolecular materials such as nylon or LCP etc.In addition, on two axial end faces of fall-out preventing component 212, promptly with radial bearing mechanism 204 in opposite directions face 213 and form on parts 207 face 214 in opposite directions with the space, be formed with respectively dynamic pressure produce with

groove

213a, 213a ... or 214a, 214a ...

On the space forms parts 207, be formed with fall-out preventing component 212 and can be embedded in wherein recess 207a, around fall-out preventing component 212, formed the space thus.In addition, be formed at fall-out preventing component 212 and space form the gap between the parts 207 or be formed at fall-out preventing component 212 and radial bearing mechanism 204 between the gap in be filled with lubricant oil.

As mentioned above, in bearing unit 201B, as thrust-bearing mechanism 205, has the Hydrodynamic bearing type structure of using fall-out preventing component 212 and space to form parts 207, axle 202 obtains the supporting of Hydrodynamic bearing and can rotate freely relatively, therefore, vibrate for a short time, the recording device that is adapted at for example CD drive and hard disk drive etc. is with using in the motor.

Manufacture method about bearing unit 201B, though it is basic identical to the operation of (4) with (1) shown in Figure 13 A～Figure 13 D, but need produce with the part of

groove

213a, 214a and radial bearing mechanism 204 and space and form supplying lubricating oil between the parts 207 to being formed with dynamic pressure on the fall-out preventing component 212, so that produce set dynamic pressure during the axle rotation.This point is formed the precision decision of parts 207 by fall-out preventing component 212 and space.

In addition, this example is cited is that dynamic pressure produces with groove 213a, 214b and is formed at structural type on the fall-out preventing component 212, but be not limited in this, also can adopt radial bearing mechanism 204 with fall-out preventing component 212 in opposite directions end face or the space form parts 207 with fall-out preventing component 212 face in opposite directions on form dynamic pressure and produce with other forms such as grooves.

Below, rotating driving device involved in the present invention is described.

Figure 16 illustrates an example of the rotating driving device that uses bearing unit 201 involved in the present invention, is the sectional view that the application in fan motor is showed.Also can be to substitute bearing unit 201 and the device of

use bearing unit

201A, 201B.

The stator department 217 that rotating driving device 215 comprises rotor part 216 and has bearing unit 201.

The rotor part 216 that constitutes solid of rotation (rotor) have rotor yoke iron 218 and magnet 219, blade 220,220 ..., axle 202 the end of bringing into play function as running shaft is fixed on the locational flange 221 of the rotating center that is formed at rotor part 216 by mode such as being pressed into.In addition, the magnet (plastic magnet etc.) 219 of the annular that on the inner peripheral surface of rotor yoke iron 218, has been adhesively fixed with along its circumferential magnetization, in the outer circumferential face upper edge of the cylindrical part 216a that constitutes rotor part 216 circumferentially across set angle be provided with a plurality of blades 220,220 ...

Bearing unit 201 is configured in the stator department 217 as the axle support mechanisms that the axle 202 that is rotated made it to support with rotating freely with rotor part 216.That is, bearing unit 201 is loaded in the recess 223 of formed support 222a cylindraceous on the stator yoke iron 222 that constitutes stator department 217, is fixed by mode such as being pressed into or bonding.In addition, on the peripheral part of support 222a, be provided with the inner peripheral surface position in opposite directions of magnet 219 and comprise unshakable in one's determination 224 and the coil portion 226 of coil 225, constituted the driving mechanism 227 of solid of rotation with magnet 219 and rotor yoke iron 218.

On the shell 228 of rotating driving device 215, form porose 228a, when 226 energisings make rotor part 216 rotations to coil portion, will be shown in the arrow A of Figure 16, after air flowed into from hole 228a, formed exhaust outlet (not shown) was to outside drain from the shell 228.

By installation shaft bearing unit 201 in this fan motor, can access lubricant oil can leakage, long service life and have the structure of very high reliability.In addition,, adopted Hydrodynamic bearing type structure, therefore, had the very high reliability and the motor of high speed rotating but can produce as radial bearing mechanism 204.Therefore, be applicable in the cooling fan of the exigent equipment of cooling performance for example.As the application in cooling system of in computer, using that heaters such as CPU are cooled off, can enumerate heat that the heater of sening as an envoy to produces to heat sink, with fan this radiator is carried out air cooled structure example.

About the installation attitude of rotating driving device 215, with regard to the direction that postpones of axle 202 towards where all can, therefore, using with the state that turns upside down with direction shown in Figure 16 does not have obstruction yet, the restriction that is subjected to during installation is little.

In addition, rotating driving device involved in the present invention is not limited in fan motor, can also be widely used among the motor etc. of various electronic equipments such as the whirligig of disc class recording medium and rotary magnetic head magnetic drum unit.

As mentioned above, what bearing unit involved in the present invention adopted is a kind of like this structure, promptly, after the parts that the space forms necessity such as parts and Sealing are installed on the running shaft support mechanism such as radial bearing, only reserve very little space G in the exposed division office of axle, therefore structure to seamlessly keeping with the bearing housing parts of formation such as macromolecular material around each parts, does not have oil leak from bearing means inside.Therefore, according to the present invention, the bearing unit that can obtain long service life and have very high reliability.

In addition, its manufacturing process of bearing unit involved in the present invention is simple, does not need to carry out the management of fillers such as binder and to the operations such as inspection of sealing condition.

In addition, with the ester moulding bearing housing, therefore, not only cost is low when having used the Hydrodynamic bearing that adopts sintering metal for bearing unit involved in the present invention, and long service life, reliability height.

In addition, even bearing unit involved in the present invention pore volume between Sealing and axle hour also can guarantee necessary accuracy, can reduce the discreteness of space G.

Below, to bearing unit involved in the present invention and in conjunction with the accompanying drawings as another example of the motor of the rotating driving device that uses this bearing unit.

Here, the example that is set forth in employed motor in the sink set in the electronic equipments such as notebook computer of information processor as the calculation process of carrying out various information describes.Inside at this notebook computer etc. is provided with sink.This sink has the base of metal manufacturing, fan drum 304 and the radiator that is installed in the motor 301 on this base, the fan 303 that rotates under the driving of this motor 301, holds fan 303.The motor 301 that the fan 303 that drives this sink is rotated is elaborated below.

The motor 301 that uses bearing unit 330 involved in the present invention has rotor 311 and stator 312 as shown in figure 17.

Stator 312 is arranged under the driving that is used for being contained in this motor 301 top plate 304a one side with the fan drum 304 of the fan 303 of motor 301 rotations integratedly.Stator 312 has stator yoke iron 313, bearing unit 330, coil 314 involved in the present invention and the iron core 315 of this coil 314 of reeling.Stator yoke iron 313 both can be integrally formed with the top plate 304a of fan drum 304, promptly the part by fan drum 304 constitutes, and also can form separately in addition.Stator yoke iron 313 is for example formed by iron.Bearing unit 330 is by being pressed into or bonding and then carry out the bonding center portion that is fixed on stator yoke iron 313 when being pressed into and be in the retainer 316 that tubular forms.

Bearing unit 330 is pressed in retainer 316 wherein and is cylindric formation with stator yoke iron 313 with being integral.

On the peripheral part of the retainer 316 that is integrally formed with stator yoke iron 313, as shown in figure 17, be equipped with unshakable in one's determinationly 315, and should be wound with the coil 314 that needs to supply with operating current on the iron core 315 to it.

The rotor 311 that constitutes motor 301 with stator 312 is installed in the supporting that obtains bearing unit 330 and on the running shaft 331 that can rotate, can rotates with running shaft 331 one.The fan 303 that rotor 311 has rotor yoke iron 317 and has a plurality of blades 319 that rotate with this rotor yoke iron 317 one.The blade 319 of fan 303 can be integrally formed with rotor yoke iron 317 by carrying out outsourcing to be shaped on the outer circumferential face of rotor yoke iron 317.

On the inner peripheral surface of the cylindrical portion 317a of rotor yoke iron 317, be provided with the rotor magnet 320 of ring-type opposite to each other with the coil 314 of stator 312.This changes in magnet 320 is the plastic magnets that alternately are magnetized to the S utmost point and the N utmost point on circumferentially, by adhesive securement on the inner peripheral surface of rotor yoke iron 317.

Rotor yoke iron 317, can install like this, that is, be pressed into by the flange 321 center portion, that be provided with through hole 321a that will be arranged on plat part 317b on the assembly department 332 of the front end that is arranged on the running shaft 331 that obtains bearing unit 330 supportings, and can rotate with running shaft 331 one.

Motor 301 with said structure, when by the drive circuit unit that is located at motor 301 outsides with set powered-on mode when stator 312 lateral coils 314 are supplied with operating currents, by magnetic field and the rotor 311 side rotor magnets 320 formed magnetic field interactions that coil 314 is produced, can make rotor 311 and the rotation of running shaft 331 one.Along with the rotation of rotor 311, the fan with a plurality of blades 319 303 that is installed on this rotor 311 also rotates with rotor 311 one.When fan 303 rotations, to install air outside by the opening on the housing that is located at the formation computer sucks in, and then make it in housing, to flow, flow through the radiator in being located at housing and discharge to outside by openings, thereby the heat that heater element is produced distributes outside the computer body, and the computer body is cooled off.

Below, employed bearing unit 330 in this motor 301 is described in detail.

As Figure 17, Figure 18 and shown in Figure 19, the space in the outside that the bearing unit 330 that the running shaft 331 of said motor 301 is made it to support with rotating freely has radial bearing 333 that running shaft 331 is supported on circumferentially, be formed at this radial bearing 333 forms parts 334, hold this space forms the bearing housing 337 of parts 334 and is formed at the space and form communication paths 350 between parts 334 and the radial bearing 333.

Radial bearing 333 is cylindric by sintering metal and forms.Radial bearing 333 is formed with dynamic pressure and produces groove 343,344 with constituting Hydrodynamic bearing as the lubricant oil 342 that is filled in the viscous fluid in the bearing housing 337 on the inner peripheral surface that running shaft 331 passes.

Dynamic pressure produces groove 343,344 as shown in figure 20, is that a pair of groove 343a, the 344a of V-shaped formation on the inner peripheral surface of radial bearing 333 passes through connecting

groove

343b, 344b upwards continuous formation of week.Dynamic pressure produces groove the 343, the 344th, with the forward end of V-shaped a pair of

groove

343a, 344a towards the formation of the sense of rotation R1 ground of running shaft 331.In this example, dynamic pressure produces groove the 343, the 344th, be radial bearing 333 cylindraceous axially on be arranged above and below and forming, dynamic pressure generation groove 343 is formed at the open axle of axle and exposes side, and the non-axle that dynamic pressure generation groove 344 is formed at a non-opening exposes side, is thrust-bearing one side described later.Set dynamic pressure produces the quantity of groove 343,344 and big I and carries out suitable selection according to the size of radial bearing 333 and length etc. on the radial bearing 333.This radial bearing 333 also can be made by brass, stainless steel or macromolecular material.

The radial bearing 333 that forms as Hydrodynamic bearing, when the running shaft 331 that passes from this radial bearing 333 rotates continuously around the direction of centre line C L arrow R1 in Figure 20, be lubricant oil 342 circulation in dynamic pressure produces groove 343,344 in being filled in bearing housing 337, under the situation of generation dynamic pressure between the inner peripheral surface of the outer circumferential face of running shaft 331 and radial bearing 333, running shaft 331 supported.The dynamic pressure that produce this moment can make the friction factor between running shaft 331 and the radial bearing 333 become very little, and running shaft 331 is rotated sleekly.

But in this bearing unit 330, it is wideer than the width of dynamic pressure generation groove 343 on thrust direction at the width on the thrust direction that dynamic pressure produces groove 344.Therefore, axle exposes that the side dynamic pressure produces dynamic pressure amount P343 that groove 343 produced, the relation exposed between the dynamic pressure amount P344 that side dynamic pressure generation groove 344 produced with non-axle is P343＜P344.

Below, expose this problem of side dynamic pressure amount P343 greater than axle and describe with regard to making non-axle expose side dynamic pressure amount P344.The generation of dynamic pressure can bring the variation of static pressure simultaneously.Here, when formed dynamic pressure produce that groove produces be the concerning of the P343＞P344 opposite with above-mentioned relation the time, promptly, when axle exposes side dynamic pressure amount and exposes side dynamic pressure amount greater than non-axle, the distribution of static pressure will be opposite with the distribution of dynamic pressure, therefore, expose side with axle and compare, the static pressure that exposes sealed axle head one side of side as non-axle rises.Can cause the phenomenon of axial top pushing, the i.e. generation of axle rising phenomenon with the produced simultaneously static pressure pressure of this rotation.

In order to prevent the generation of this axle rising phenomenon, in this bearing unit 330, dynamic pressure produces groove 343 to be wider than the width formation that dynamic pressure produces groove 344, dynamic pressure amount P343 and non-dynamic pressure amount P344 that exposes side that feasible axle exposes side are P343＜P344, the static pressure that axle exposes side exposes the side static pressure greater than non-axle, tends to the axle band is exposed side, is the situation that thrust-bearing side described later sucks to non-axle thereby cause.

The space that is located at the outside of radial bearing 333 forms parts 334 as Figure 19 and shown in Figure 21, is cylindric formation and has shape that radial bearing 333 containings are got up, is for example formed by synthetic resin.

As Figure 18 and shown in Figure 21, the space forms space that parts 334 fence up by lateral parts and underside portion with radial bearing and forms hardware body 335 and the space that the summit portion of radial bearing fences up is formed parts cap 336 and constitute.Form the central position of parts cap 336 in the space, be provided with can make that the running shaft 331 that obtains radial bearing 333 supportings and can rotate freely passes wear axis hole 336a.

The central position of inner face that forms the underside portion of hardware body 335 in the space has formed thrust-bearing 346, and running shaft 331 set bearing support 331a on an end on the thrust direction that 346 pairs of this thrust-bearings obtain radial bearing 333 supportings supports and enable rotation.Thrust-bearing 346 usefulness synthetic resin form the space and form parts 334 and make it this thrust-bearing of double as.Thrust-bearing 346 is to form as a kind of trunnion bearing that the bearing support 331a that is the running shaft 331 that circular arc or front end tapered form is carried out a supporting.

Form the top of hardware body 335 in the space, be provided with along circumference and the space can be formed parts cap 336 with its claw 335a with the securing claw type of state of the summit portion covering of radial bearing.In addition, form in the space on the lateral parts of hardware body 335, be provided with after holding radial bearing, make radial bearing outer circumferential face to the opening portion 335b that exposes outside.

The space forms parts 334 and formed by synthetic resin, forms but also can use by metal, can also use the combined material of synthetic resin and metal, there is no particular restriction for material.Here, when the space forms parts 334 and formed by synthetic resin, have and be convenient to carry out well-designed and problem such as phase place location between solution and the radial bearing and advantage such as cheap its shape.For example, form parts 334 employed resin materials as the space, can use synthetic resin such as fluorine class synthetic resin such as polyimide, polyamide, polyoxymethylene, teflon Te Fulong (TM trade mark), nylon and PC (polycarbonate (PC)), ABS synthetic resin such as (acrylonitrile-butadiene-styrene resins).

Between space formation parts 334 and radial bearing 333, be formed with communication paths 350.This communication paths 350 makes end axle outstanding in the radial bearing 333, on the thrust direction be communicated with another end.That is, communication paths 350 makes an end that forms thrust-bearing 346 1 sides be communicated with the other end of wearing axis hole 336a one side that the space forms parts cap 336.

This communication paths 350 is as Figure 21 and shown in Figure 22, by the 1st groove 351 on the thrust direction on the outer circumferential face that is formed at radial bearing 333, be formed at the 2nd groove 352 on the end face of thrust-bearing 346 those sides of radial bearing 333 and the 3rd groove 353 that is formed on another end face of radial bearing 333 constitutes.

This communication paths also can be arranged on the space and form parts 334 1 sides as Figure 23 and shown in Figure 24.That is, be located at the communication paths 360 that the space forms on parts 334 1 sides also can form the 1st groove 361 on the thrust direction on the inner peripheral surface of hardware body 335, be formed at the space and form the 2nd groove 362 on the inner face of underside portion of hardware body 335 and be formed at the 3rd groove 363 that the space forms on the inner face of parts cap 336 and constitute by being formed at space that the space forms parts 334.Can also by above-mentioned be located at the 1st on the radial bearing～the 3rd groove 351～353 and be located at the 1st～the 3rd groove 361～363 that the space forms on the parts 334 combine.

As mentioned above, in this bearing unit 330, though dynamic pressure produces the width of groove 344 to be wider than the width formation that dynamic pressure produces groove 343, the dynamic pressure amount P344 that non-axle exposes side exposes the dynamic pressure amount P343 of side greater than axle, thereby can suppress the generation of the axle rising phenomenon that causes because of axle rotation, but reduce because non-axle exposes the static pressure of side shaft end, can produce residual air and expand at the axle head of sealing and lubricant oil extruded and the new problem of leakage phenomenon takes place.

Because this communication paths 350 or communication paths 360 make that the open sides of outstanding running shaft 331 is communicated with non-open sides from radial bearing 333, thereby the static pressure that above-mentioned non-axle exposes the side shaft end can not reduce, therefore, can prevent from lubricant oil to be extruded because of air residual in the bearing housing or the air expansion that is dissolved in the lubricant oil.In other words, because communication paths 350,360 can make the dynamic pressure that is located on the radial bearing 333 produce the pressure short circuit at the two ends of groove 343,344, therefore, can not form pressure difference, thereby a rising phenomenon can not take place yet.

Accommodating bearing housing 337 that the space forms parts 334 as shown in figure 19, have and form parts 334 and contain the shape of getting up being space cylindraceous approximately, is by carrying out integrally formed parts that form of synthetic resin.

As shown in figure 19, bearing housing 337 is by tubular bearing housing body 338, be integrally formed with bearing housing body 338 and with the bottom closure 339 end sealing, that constitute the one end portion of bearing housing body 338, and the top seal portion 340 the other end part, that be integrally formed with bearing housing body 338 that constitutes bearing housing body 338 constitutes.Central position in top seal portion 340, what be provided with that the running shaft 331 that can make 333 supportings of the radial bearing that obtains being contained in the bearing housing 337 and can rotate freely passes wears axis hole 341.

As above the bearing housing 337 of Gou Chenging is to adopt the outsourcing mould-forming method that the synthetic resin material is shaped with the shape that will about tubular space forms parts 334 and encase, thereby makes space formation parts 334 be positioned at all sides of bearing housing body 338 and integrally formed.

At this moment, the part of the outer circumferential face of radial bearing 333, therefore the opening portion 335b that forms hardware body 335 from the space, will become one with the bearing housing 337 that outer packet shaping forms to exposing outside.

For the synthetic resin material that constitutes bearing housing 337,, preferably use for being filled in lubricant oil 342 rubber-likes in the bearing housing 337, having the material of big wrapping angle with respect to lubricant oil 342 though be not particularly limited.Form parts 334 owing on bearing housing 337, form the space, therefore, preferably use synthetic resin material with good lubricity.For example, bearing housing 337 preferably uses synthetic resin such as fluorine class synthetic resin, teflon Te Fulong, nylon such as polyimide, polyamide, polyoxymethylene to form.In addition, also can use PC (polycarbonate (PC)), ABS synthetic resin such as (acrylonitrile-butadiene-styrene resins).Even can be by forming with the liquid-crystalline polymer that high precision is shaped.Particularly use the occasion of liquid-crystalline polymer, can maintain lubricant oil, obtain the excellent abrasive energy at bearing housing 337.

But, in this bearing unit 330, be by the so-called axle both ends open type that communication paths 350 makes that the two ends of outstanding axle 331 are communicated with in the radial bearing 333 is set.And in the existing axle both ends open profile shaft bearing unit, exist the problem that lubricant oil splashes easily when being subjected to impacting.And in this bearing unit 330, because forming parts 334 with radial bearing 333 and space, its bearing housing 337 constitutes jointless structure all airtight except wearing axis hole 336a, therefore, although the outstanding axle open sides from radial bearing of axle is connected through communication paths 350 with non-axle open sides, but with respect to the outside, wearing the axis hole 336a of being provided with on bearing housing 337 is airtight.That is, therefore this bearing unit 330, can prevent that lubricant oil from splashing owing to be that communication paths 350 is arranged on and is seamless state and forms, be in the airtight bearing housing with respect to the outside when being subjected to impacting.

Obtain being arranged on the radial bearing 333 in the bearing housing 337 and be integral the supporting of thrust-bearing 346 of setting and the running shaft 331 that can rotate freely with bearing housing 337, bearing support 331a its axial region body 331b, that obtain thrust-bearing 346 supporting is circular arc or the front end tapered forms, and the other end is provided with the assembly department 332 that can install as the rotor 331 of for example motor 312 of solid of rotation.Here, axial region body 331b forms with identical diameter with assembly department 332.

As shown in figure 19, running shaft 331 is the supportings that obtain bearing housing 337 with following state, promptly, the bearing support 331a of one end obtains the supporting of thrust-bearing 346, the outer circumferential face of axial region body 331b obtains the supporting of radial bearing 333, and the assembly department 332 that is located at the other end highlights from the axis hole 341 of wearing in the top seal portion 340 that is arranged on bearing housing body 338.

In addition, on running shaft 331, between bearing support 331a and axial region body 331b, be provided with and prevent the come off slot part 331c of usefulness of axle.Use slot part 331c accordingly with this Drop-proof, form on the parts 334, be provided with pad 349 with mechanism as the axle Drop-proof in the space.The two can fasten the axle Drop-proof with slot part 331c and pad 349, thereby very convenient during hand assembled.This pad 349 is made by macromolecular materials such as nylon, polyamide, polyimide or metals such as stainless steel, phosphor bronze.

But, as wearing axis hole 341, do not rotate with the inner peripheral surface sliding contact ground of wearing axis hole 341 in order to make through this running shaft of wearing in the axis hole 341 331, be to form with the internal diameter bigger than the external diameter of axial region body 331b.At this moment, wearing axis hole 341 forms and forms the lubricant oil 342 that is enough to prevent to be filled in the bearing housing 337 space 345 from the interval c of bearing housing 337 internal leakages between the outer circumferential face with side face and axial region body 331b within it.Be formed with as mentioned above the top seal portion 340 of wearing axis hole 341 that can between itself and running shaft 331, form the space 345 of lubricant oil 342 leakages that can prevent to be filled in bearing housing 337 in and constituted oil seal portion.

The top seal portion 340 that is integrally formed with it on bearing housing 337 is formed by synthetic resin such as polyimide, polyamide or nylon, and therefore, the inner peripheral surface that can guarantee to wear axis hole 341 reaches the degree of 60 degree with respect to the wrapping angle of lubricant oil 342.Bearing unit 330 involved in the present invention is owing to needn't just can make lubricant oil 342 have bigger wrapping angle with respect to top seal portion 340 by the coating interfacial agent in the top seal portion 340 that comprises the inner peripheral surface of wearing axis hole 341 that constitutes oil seal portion, therefore, can prevent that lubricant oil 342 from moving outside bearing housing 337 via wearing axis hole 341 under the action of centrifugal force that running shaft 331 rotations are produced.

In addition, running shaft 331 with the inner peripheral surface of wearing axis hole 341 outer circumferential face in opposite directions on be provided with tapered portion 347.Tapered portion 347 be inclined to make be formed at the outer circumferential face of running shaft 331 with the inner peripheral surface of wearing axis hole 341 between space 345 to foreign side's expansion of bearing housing 337.This tapered portion 347 makes that by the outer circumferential face of running shaft 331 with wear in the space 345 that the inner peripheral surface of axis hole 341 forms and form pressure gradient, generation will be filled in the power that bearing housing 337 interior lubricant oil 342 attract to the inside of bearing housing 337.When running shaft 331 rotations, lubricant oil 342 is in the state that tends to be inhaled into bearing housing 337 inside, therefore, the dynamic pressure of the radial bearing 333 that lubricant oil 342 is reliably entered be made of Hydrodynamic bearing produces groove 358 and produces dynamic pressure, realization is to the stable supporting of running shaft 331, but also the lubricant oil 342 that can prevent to be filled in the bearing housing 337 leaks.

In bearing unit involved in the present invention 330, enter dynamic pressure set on the radial bearing 333 that constitutes Hydrodynamic bearing and produce the lubricant oil 342 that produces dynamic pressure in the groove 358, be as Figure 19 and shown in Figure 25, in bearing housing 337, fill from the situation of exposing by the tapered portion 347 and the formed space 345 of inner peripheral surface of wearing axis hole 341 that are formed on the running shaft 331.That is, lubricant oil 342 can be filled in the gap in the bearing housing 337, and then soaks and be contained in the radial bearing of being made by sintering metal 333.

Here, in the tapered portion 347 that forms on the running shaft 331 and wear that formed space 345 describes between the inner peripheral surface of axis hole 341.The minimum interval in this space 345 is equivalent to the outer circumferential face of running shaft 331 and wears formed interval c between the inner peripheral surface of axis hole 341, and this interval c is advisable with 20 μ m～200 μ m, is preferably in about 100 μ m.If at interval c is less than 20 μ m, then with the bearing housing 337 of synthetic resin by integrally formed manufacturing bearing unit 330 time, be difficult to guarantee forming accuracy.If the interval c in space 345 is greater than 200 μ m, then when bearing unit 330 was subjected to impacting, the lubricant oil 342 that is filled in the bearing housing 337 can be splashed to outside the bearing housing 337, and its impact resistance reduces.

Preventing to be filled in the impact resistance G that the lubricant oil 342 in the bearing housing 337 are splashed to when being subjected to impacting outside the bearing housing 337 can be represented by following formula (1).

G＝(12γcosβ/2ρc ²)/g……(1)

Wherein, γ: lubricated oil surface tension

β: the wrapping angle of lubricant oil

ρ: the density of lubricant oil

C: running shaft and wear interval between the axis hole

G: free-fall acceleration

By formula (1) as can be known, the interval c's in impact resistance G and space 345 square is inversely proportional to.

In addition, the ascending amount h of the pasta that causes of thermal expansion can be represented by following formula (2).

h＝VαΔt/2πRc ……(2)

Wherein, V: lubricant oil loading

α: thermal expansion coefficient

Δ t: temperature variation

R: axle radius

By formula (2) as can be known, pasta ascending amount h is inversely proportional to the size of interval c, and therefore, c can improve impact resistance G though reduce at interval, and temperature will cause that the fuel head h of lubricant oil 342 sharply raises when raising, and need to increase to wear axis hole 341 thickness in the axial direction.

According to calculating, in having the bearing unit 330 of running shaft 331 that the diameter of axle is diameter 2mm～diameter 3mm, if make running shaft 331 and the interval c that wears formed space 345 between the axis hole 341 reach the degree of 100 μ m, wear axis hole 341 height H 1, be that the thickness of the top seal portion 340 of bearing housing 337 is about 1mm, impact resistance is reached more than the 1000G, high-temperature stability reaches 80 ℃, can constitute the bearing unit 330 that can prevent to be filled in the high reliability that the lubricant oil 342 in the bearing housing 337 splash.

In addition, bearing unit 330 involved in the present invention be provided be inclined to make be formed at the outer circumferential face of running shaft 331 with the inner peripheral surface of wearing axis hole 341 between the interval c in space 345 to the tapered portion 347 of foreign side's expansion of bearing housing 337, therefore, can be by the outer circumferential face of running shaft 331 with wear among the interval c in the space 345 that the inner peripheral surface of axis hole 341 forms and form pressure gradient, under the action of centrifugal force that is produced when running shaft 331 rotations, generation will be filled in the power that the lubricant oil 342 in the bearing housing 337 sucks to the inside of bearing housing 337.

That is, in bearing unit involved in the present invention 330, being formed at the outer circumferential face of running shaft 331 and wearing space 345 between the inner peripheral surface of axis hole 341, is that the sealing of abutment surface tension force prevents that lubricant oil 342 from splashing.

Surface tension is sealed into the row explanation here.The surface tension sealing is the encapsulating method that utilizes the wicking of liquid.The height h that capillary tube as shown in figure 26 can make liquid rise can followingly obtain.

2πrγcosθ＝mg ……(3)

M is represented by following formula (4).

m＝πr2hρ……(4)

Wherein, m: the fluid mass in the h scope in the pipe

R: capillary radius

γ: the surface tension of viscous fluid

θ: the wrapping angle of viscous fluid

ρ: the density of viscous fluid

G: gravity accleration

Can derive following formula (5) by formula (3), formula (4).

h＝2γcosθ/rρg ……(5)

In general, formula (6) expression of the two relation of pressure P and fluid level below available.

P＝ρgh ……(6)

Can obtain formula (7) from formula (5), formula (6) here, about pressure P

P＝2γcosθ/r ……(7)

In formula (7), pressure P means the suction pressure that convection cell attracts.By formula (7) as can be known, the thin more pressure P of capillary tube is then big more.

In the superincumbent explanation, the formula of enumerating that is the capillary tube section configuration when circular, and bearing unit 330 involved in the present invention is to enter the outer circumferential face that is formed at running shaft 331 and the lubricant oil 342 worn in the space 345 between the inner peripheral surface of axis hole 341 is circular as shown in figure 27.Lifting height h1 as the lubricant oil 342 of liquid under this occasion can try to achieve from following formula (8).

2π(R+r)γcosθ＝mg ……(8)

M can be represented by following formula (9).

m＝π(R2·r2)hρ……(9)

Can obtain following formula (10) by formula (8), formula (9)

h1＝(2γcosθ)/((R·r)ρg)……(10)

If establish (Rr) for being formed at the outer circumferential face of running shaft 331 and wearing the interval c in the space 345 between the inner peripheral surface of axis hole 341, then formula (10) will become formula (11).

h＝(2γcosθ)/(cρg)……(11)

Therefore, be the occasion of ring in the section configuration of lubricant oil 342, suction pressure can be represented by formula (12).

P＝2γcosθ/c ……(12)

Enumerate the object lesson that calculates here.

When the outer circumferential face that is formed at running shaft 331 and the interval c that wears the space 345 between the inner peripheral surface of axis hole 341 are that the surface tension γ of 0.02cm (0.2mm), viscous fluid is 30dyn/cm ², lubricant oil 342 wrapping angle θ when being 15 °, the suction pressure that obtains from formula (13) is 2.86 * 103 air pressure (a tm).

P＝2×30×cos15°/0.02＝3.00×103dyn/cm ²＝

2.86 * 103 air pressure (atm) ... (13)

By formula (12) as can be known, the narrow more suction pressure P of the interval c in space 345 is big more.Therefore, on running shaft 331, be provided with tapered portion 347 can narrow down direction from the lubricant oil 342 as viscous fluid to the interval in space 345 c, be that bearing housing 337 internal direction suck.

For example, as shown in figure 28, as different position t1 of the diameter of tapered portion set on the running shaft 331 347 and the suction pressure P1 of t2, P2, because the outer circumferential face of the running shaft 331 at t1 place and wear interval c1 between the inner peripheral surface of axis hole 341, and the outer circumferential face of the running shaft 331 at t2 place and the pass of wearing the interval c2 between the inner peripheral surface of axis hole 341 are c1＜c2, therefore, by formula (12) as can be known, P1＞P2 narrows down lubricant oil 342 and increases to the inner suction pressure P that suck of bearing housing 337 along with outer circumferential face that is formed at running shaft 331 and the interval c that wears the space 345 between the inner peripheral surface of axis hole 341.

As mentioned above, by prevent from formation to be filled in the bearing housing 337 lubricant oil 342 to the sealed department of bearing housing 337 external leaks, be formed at the outer circumferential face of running shaft 331 with the inner peripheral surface of wearing axis hole 341 between the interval c in space 345 towards the mode that the internal direction of bearing housing 337 diminishes tapered portion 347 is set, can produce pressure gradient being arranged in by the outer circumferential face of running shaft 331 and wearing on the lubricant oil 342 in the formed space 345 of inner peripheral surface of axis hole 341.That is, being applied to pressure gradient on the lubricant oil 342 is that the internal direction of the bearing housing 337 that 345 interval c diminishes towards the space becomes big gradually.By on lubricant oil 342, producing this pressure gradient, make lubricant oil 342 be subjected to it is sucked the effect of the pressure P in the bearing housing 337 all the time, therefore, even if under the situation of running shaft 331 rotations, air can not sneaked in the lubricant oil 342 that is present in the space 345 yet.

In the occasion that above-mentioned tapered portion 347 is not set, promptly, as shown in figure 27, the outer circumferential face of running shaft 331 and wear interval c changeless occasion on the short transverse of wearing axis hole 341 in the space 345 between the inner peripheral surface of axis hole 341, enter the outer circumferential face of running shaft 331 and wear on the lubricant oil 342 in the space 345 between the inner peripheral surface of axis hole 341 and can not produce pressure gradient, therefore, lubricant oil 342 will be present in the space 345 equably.That is, thus the interval c between the inner peripheral surface that enters the outer circumferential face by making running shaft 331 and wear axis hole 341 narrows down and makes lubricant oil 342 in its space 345 that plays a role as sealed department sometimes because running shaft 331 rotations and move space 345 in air E is infiltrated.If air E sneaks in the lubricant oil 342 as mentioned above, then air can expand along with the variation of variation of temperature, air pressure, causes lubricant oil 342 to be splashed to outside the bearing housing 337 from the space 345 that constitutes sealed department.

With respect to this, as bearing unit involved in the present invention 330, can make the outer circumferential face that is formed at running shaft 331 and to wear the tapered portion 347 that the interval c in the space 345 between the inner peripheral surface of axis hole 341 diminishes towards bearing housing 337 internal direction by being provided with, can on the lubricant oil in entering space 345 342, produce towards bearing housing 337 internal direction pressure increased pressure gradients, therefore, in the time of can preventing running shaft 331 rotations air E is brought in the lubricant oil 342.

In addition, when being provided with aforesaid tapered portion 347, even running shaft 331 exists when eccentric with respect to the set axis hole 341 of wearing on the bearing housing 337, the lubricant oil 342 that also can prevent to enter the outer circumferential face that is formed at running shaft 331 and wear in the space 345 between the inner peripheral surface of axis hole 341 is splashed to outside the bearing housing 337, moreover, lubricant oil 342 is entered on the complete cycle of running shaft 331, prevent that the lubricant oil 342 around the running shaft 331 from interrupting, guarantee running shaft 331 stable rotations.

When running shaft 331 on respect to bearing housing 337 the set axis hole 341 of wearing exist when eccentric, if aforesaid tapered portion 347 is not set, then as shown in figure 30, lubricant oil 342 can be concentrated to the narrower position of the outer circumferential face of running shaft 331 and interval c between the inner peripheral surface of wearing axis hole 341, and, air E is sneaked in the position lubricant oil 342 appearance interruptions of the interval c broad of a side in contrast.If air E sneaks in the lubricant oil 342, then air E can expand along with the variation of variation of temperature, air pressure, causes lubricant oil 342 to be splashed to outside the bearing housing 337 from the space 345 that constitutes sealed department.

With respect to this, as bearing unit involved in the present invention 330, by tapered portion 347 is set on running shaft 331, even if running shaft 331 on respect to bearing housing 337 the set axis hole 341 of wearing exist under the eccentric situation, also can be as shown in figure 31, on the elliptical orbit that the running shaft 331 of off-centre is rotated, must have the identical space 345 of c at interval, the interval c that is formed at the outer circumferential face of the running shaft 331 on this elliptical orbit and wears the space 345 between the inner peripheral surface of axis hole 341 is certain in the complete cycle scope of running shaft 331 shown in figure 32, thereby lubricant oil 342 can not take place to the narrower concentrated phenomenon in position of interval c, therefore, can prevent that lubricant oil 342 is from the space 345, to such an extent as in bearing housing 337, splash out.

Though above-mentioned bearing unit 330 running shafts 331 are provided with tapered portion 347, also can on the inner peripheral surface of wearing axis hole 341 of bearing housing 337, tapered portion 348 be set as shown in figure 33.

Below, the manufacturing process of the bearing unit involved in the present invention 330 that as above constitutes is described.

When making bearing unit 330 involved in the present invention, the space is formed the outside that parts 334 are installed in radial bearing 333 assemble temporarily.Radial bearing 333 and space form parts 334 when assembling temporarily as shown in figure 34, form in the space install on the hardware body 335 can embed the bearing support 331a that is arranged on running shaft 331 and the axle Drop-proof between the axle body 331b with among the slot part 331c, as the pad 349 of an anti-shedding mechanism.Secondly, installing space forms hardware body 335 and the space forms parts cap 336 on as the radial bearing 333 of Hydrodynamic bearing.At this moment, formed thrust-bearing 346 in the inside of space formation hardware body 335.In addition, form formation communication paths 350 between parts 334 and the radial bearing 333 in the space.

Secondly, the radial bearing 333 and the space formation parts 334 of assembling temporarily are installed in the mould, as shown in figure 35, in the periphery that the radial bearing 333 and the space of this interim assembling form parts 334, carry out the outer packet shaping of above-mentioned certain synthetic resin and form bearing housing 337.At this moment, outside during packet shaping bearing housing 337, the space forms parts 334 and becomes one with it in the inside of bearing housing 337, is sandwiched between the top seal portion 340 that is integrally formed up and down and bottom closure 339 of the bearing housing body 338 of tubular, and its mounting point is fixed.And radial bearing 333 is outside during packet shaping bearing housing 337, the opening portion 335b and the bearing housing 337 that form parts 334 by the space become one, be sandwiched between the top seal portion 340 that is integrally formed up and down and bottom closure 339 of the bearing housing body 338 of tubular, its mounting point is fixed.In addition, during packet shaping bearing housing 337, form stopping of parts 334 outside, thereby synthetic resin can inflow space form in the communication paths 350 between parts 334 and the radial bearing 333 owing to be subjected to the space.

Secondly, as shown in figure 36, running shaft 331 is passed setly in the top seal portion 340 wear axis hole 341 and insert in the bearing housing 337.At this moment, use among the slot part 331c by resiliently deformable embedding axle Drop-proof as the pad 349 of axle anti-shedding mechanism, running shaft 331 passes radial bearing 333 and is inserted in the bearing housing 337 with its bearing support 331a and thrust-bearing 346 state of contact.The running shaft 331 that obtains thrust-bearing 346 and radial bearing 333 supportings can rotate in bearing housing 337.

After inserting running shaft 331 in the bearing housing 337, packing lubrication oil 342 in bearing housing 337.The filling of lubricant oil 342 accommodates bearing housing 337 inputs of inserting running shaft 331 in the filling slot 355 of lubricant oil 356 as shown in figure 37.Secondly, with vacuum system the filling slot 355 that bearing housing is invested in is wherein vacuumized.Afterwards, will be placed in the atmosphere through the filling slot taking-up that vacuumizes, lubricant oil 342 just can be filled in the bearing housing 337.

At this moment, lubricant oil 342 will be filled into such degree, promptly, when expanding in temperature variation, prevent from wearing axis hole 341 internal leakages outside bearing housing 337, and when shrinking, can not make to be formed at running shaft 331 and to wear space 345 lack of fills between the axis hole 341 in temperature variation.That is, be designed in the scope of variation in wearing axis hole 341 of fuel head of the lubricant oil 342 that temperature variation causes.

Be lubricated the filling of glossy lubricating oil 342 in bearing housing 337 by using vacuum system to vacuumize, bearing housing 337 pressure inside will be lower than the outside.Its result can prevent that lubricant oil 342 from leaking easily from bearing housing 337.

Bearing unit 330 involved in the present invention is that its radial bearing 333 is formed by sintering metal, therefore, lubricant oil 342 can be filled in this radial bearing 333, in addition, along with the rotation of running shaft 331, lubricant oil 342 also can be filled to the dynamic pressure that produces dynamic pressure and produce in the groove 358.That is, lubricant oil 342 can be filled in all spaces in the bearing housing 337.

Form by the formed body of synthetic resin though above-mentioned bearing unit is its bearing housing, be not limited in synthetic resin, also can be to use synthetic resin that is mixed with the metallic material that can form by mould or the bearing housing that other moulding material forms.When bearing housing is formed by the material outside the synthetic resin, the lubricant oil that is filled in the bearing housing can't be guaranteed sometimes with the wrapping angle of wearing the axis hole inner peripheral surface, and in this occasion that might can't guarantee bigger lubricant oil wrapping angle, as long as at the inner peripheral surface of wearing axis hole in addition comprise the inner peripheral surface of wearing axis hole at the outer circumferential face coating interfacial agent of top seal portion to increase wrapping angle.

Its thrust-bearing of above-mentioned bearing unit forms as the part of bearing housing, but the bottom closure and the bearing housing body that also can be designed to be provided with thrust-bearing form separately, merge or method such as ultrasound fusion becomes one this bottom closure and bearing housing body by heat.

Though as above the bearing unit 330 of Gou Chenging has solved for preventing that oil leak is very useful but has occurred when existing the axle rotation because of the residual air of generation meanwhile easily or be dissolved in the shortcomings such as phenomenon that lubricant oil is extruded in the expansion (cavitation) of the air in the lubricant oil, possesses the existing problem in axle both ends open type Hydrodynamic bearing unit of the seamless bearing housing of resin manufacture.

Past, the bearing housing parts are made of a plurality of parts, the path that is provided with for the pressure short circuit that makes the radial bearing two ends, form with non-axle open sides-path-bearing housing outside-axle open sides forms, with respect to this, this bearing unit 330 is to become non-axle open sides-communication paths-axle open sides with via design, forms parts 334 for the space that forms this communication paths and constitutes fencing up around it with seamless bearing housing 337.

Promptly, this bearing unit 330 is provided with the space and forms parts 334, it is the communication paths 350 of path bearing upper end, bearing lower end that the path is set in the top and bottom of radial bearing 333, can slow down reduction as the static pressure of the non-axle open sides of the lower end that is sealed a side, thereby can prevent to cause oil leak because of squeezing on the residual air, and, lead to path outside the bearing housing and keep between axle and the bearing housing state for very little space, thereby lubricating oil splash can prevent to be subjected to impacting the time, can also prevent that viscous fluid from oozing out.Its result, this bearing unit 330 can the long term maintenance good lubricating property.

In addition, the variform bearing unit of space formation parts also can constitute as shown in Figure 38.In the following description, give identical numbering, it is described in detail omit for the part identical with bearing unit shown in Figure 19 330.

Bearing unit 370 shown in Figure 38 is compared with bearing unit 330 shown in Figure 19, and the space forms the shape difference of parts.In this bearing unit 370, the space forms parts 371 and constitutes by forming parts 372 with the 1st space that the top of the lateral parts of radial bearing 333 and shape that summit portion fences up are formed and forming parts 373 with the 2nd space that the bottom of the lateral parts of radial bearing 333 and shape that underside portion fences up are formed.Form the central position of parts 372 in the 1st space, be provided with the supporting that obtains radial bearing 333 and the running shaft 331 that can rotate freely can be passed wears axis hole 372a.

Form the central position on the inner face of underside portion of parts 373 in the 2nd space, be integrally formed into the thrust-bearing 346 of bearing support 331a set on the end on the thrust direction of running shaft 331 of the rotatably mounted supporting that obtains radial bearing 333 with it.Thrust-bearing 346 is to form the space with synthetic resin to form parts 371, as thrust-bearing and shared.Thrust-bearing 346 is to form as the trunnion bearing that the bearing support 331a that is the running shaft 331 that circular arc or front end tapered form is carried out a supporting.

Form between parts 371 and the radial bearing 333 in this space, can form communication paths equally with bearing unit 330.This communication paths makes an end on the force direction outstanding from radial bearing 333 be communicated with the other end.That is, communication paths 350 makes as the non-axle open sides that is formed with one of thrust-bearing 346 end and is communicated with the axle open sides of the other end of wearing axis hole 372a one side that forms parts 372 as the 1st space.

The bearing unit 370 that as above constitutes is same with bearing unit 330, be provided with the space and form parts, top and bottom at radial bearing, it is the communication paths of path bearing upper end, bearing lower end that the path is set, can slow down reduction as the static pressure of the non-axle open sides of the lower end that is sealed, thereby can prevent to cause oil leak because of squeezing on the residual air, and, lead to path outside the bearing housing and only keep between axle and the bearing housing state for very little space, thereby lubricating oil splash can prevent to be subjected to impacting the time, can also prevent that viscous fluid from oozing out.Its result, this bearing unit 370 can the long term maintenance good lubricating property.

As mentioned above, in using bearing unit of the present invention, form the shape of parts as the space, as long as outside during the above-mentioned bearing housing parts of packet shaping, resin can not flow in the communication paths that is formed between space formation parts and the radial bearing and get final product, and is also unrestricted for other shape.

What above-described bearing unit used as the viscous fluid of filling in bearing housing is lubricant oil, as long as but have certain viscosity, can obtain certain surface tension, also can suitably select other viscous fluid.

The present invention is not limited to above-mentioned example, also is included in the scheme that industry personnel can realize in the scope that can change design in the scope of claims records.

The possibility of utilizing on the industry

As described above, according to the present invention, coming off of axle can not be taken place in the time of can consisting of assembling, The axle that oil leak, small-sized and long service life can not take place, has very high reliability Bearing unit.

In addition, according to bearing unit involved in the present invention, it is existing that oil leak etc. can not take place Resemble the service life that can obtain to grow very much and very high reliability. And, can therefore not lead Causing the formation of device and manufacturing process becomes very complicated etc. and does not wish that situation about occurring takes place.

In addition, according to bearing unit involved in the present invention, by arrange the axle fall-out preventing component, And the parts that are intended to around these parts, form necessary space, can prevent because of impact, The reasons such as variation of air pressure and internal pressure cause axle to come off.

In addition, according to bearing unit involved in the present invention, be shaped by using macromolecular material The bearing holder (housing, cover) parts can seamlessly keep it in periphery for seal etc., thereby energy Enough prevent oil leak.

In addition, according to bearing unit involved in the present invention, be to use Hydrodynamic bearing to do Mechanism consists of for radial bearing, therefore, can support accurately axle, can prevent End because oil leak causes harmful effect, and, because the designs simplification of thrust bearing mechanism, Thereby be conducive to reduce amount of parts and man-hour and reduce cost.

In addition, more more big near inner suction pressure according to bearing unit involved in the present invention, Therefore, the lubricating oil in the space is difficult for to external leakage, and the off-centre of axle causes the journey of lubricating oil skew Degree alleviates, Reliability Enhancement.

In addition, according to bearing unit involved in the present invention, can effectively reduce vibration, and Parts by utilizing fall-out preventing component and be intended to guarantee form the space around it can make The structure of thrust bearing mechanism is simplified.

In addition, bearing unit involved in the present invention not only can be as the motor of heat abstractor Use with the bearing of the Spindle Motor of hard disk drive, can also be as the axle of other various motors Hold use, and, can be in the mechanism with rotating shaft and the section to being rotated with respect to axle Be widely used in the mechanism that part supports.

Claims

1. but one kind has axle and for the bearing unit of the gear mechanism of this axle of free rotary ground supporting, it is characterized in that, is provided with:

And across the seal oil parts of space configuration, keep the bearing housing parts of said seal oil between the said axle with the synthetic resin manufacturing of parts and said gear mechanism from periphery,

As said gear mechanism, be provided with and bear the radial bearing mechanism that is applied to the entad load on the said axle and bear the thrust-bearing mechanism that is applied to the thrust load on the said axle,

Be provided with the fall-out preventing component of said axle and dispose in order around this fall-out preventing component, to guarantee the space and as being the space formation parts that different parts form with said seal oil parts,

Keep said radial bearing mechanism and said seal oil parts and said space to form parts with said bearing housing parts,

As said thrust-bearing, the end face with said axle is curve form formation and this end face and said space and forms the parts contacting structure.

2. as the said bearing unit of claim 1, it is characterized in that,

Said bearing housing parts have used macromolecular material.

3. as the said bearing unit of claim 1, it is characterized in that,

Used Hydrodynamic bearing as said radial bearing mechanism.

4. as the said bearing unit of claim 1, it is characterized in that,

On the said axle and said seal oil with the tapered shape of interstitial part between the parts, along with approaching along this axial inner, it is big that its diameter of axle becomes gradually.

5. as the said bearing unit of claim 1, it is characterized in that,

As said thrust-bearing mechanism, use said fall-out preventing component and said space to form parts and constituted Hydrodynamic bearing.