CN101245812B - Fluid bearing device - Google Patents
Fluid bearing device Download PDFInfo
- Publication number
- CN101245812B CN101245812B CN2008100850778A CN200810085077A CN101245812B CN 101245812 B CN101245812 B CN 101245812B CN 2008100850778 A CN2008100850778 A CN 2008100850778A CN 200810085077 A CN200810085077 A CN 200810085077A CN 101245812 B CN101245812 B CN 101245812B
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- Prior art keywords
- bearing
- case
- bearing sleeve
- spindle unit
- resin
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- Expired - Lifetime
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Abstract
The invention provides a fluid bearing device, wherein a housing made of a resin composition is formed by injection molding with a sintered metal bearing sleeve as an insert piece. The housing includes a cylindrical body part, a sealing portion extending from the top of the body part radially inwards, and a bottom part closing the lower end of the body part. Of these, the body part and bottom part are integrally formed, to which the sealing portion is welded.
Description
The application is that application number is 03122917.4, and the applying date is on April 21st, 2003, and denomination of invention is divided an application for " hydrodynamic bearing device ".
Technical field
The present invention supports the hydrodynamic bearing device of rotary component about a kind of oil film that is formed by the bearing play.This bearing means is applicable to the motor type of information machine; The spindle drive motor of magneto-optical disc apparatus such as optical disk unit such as disk device, CD-ROMDVD-ROM, MDMO such as HDDFDD etc. for example; The multiaspect shape scanning motor of laser beam printer (LBP), or electric machine miniature motor such as axial fan for example.
Background technique
Above-mentioned various motor also requires speed up, cost degradation, low noiseization etc. except requiring high rotation validity.Determine that one of constituting component that these require performance is to support the bearing of the main shaft of this motor; As this bearing, and the use that on the above-mentioned requirements performance, has a FDB (especially hydraulic bearing) of good characteristic is studied or in reality, uses in recent years.
This FDB (fluid bearing) roughly divide into possess have by the lubricant oil in the bearing play produce dynamic pressure dynamic pressure generation means (dynamic-pressure generating means) so-called hydraulic bearing (dynamic bearing) and do not possess the so-called positive circular journal bearing (bearing surface is the bearing of positive toroidal) (cylindrical bearing) that dynamic pressure generation means are arranged.
For example; The hydrodynamic bearing device of in the multiaspect shape scanning motor of the spindle drive motor of disk devices such as HDD and laser beam printer (LBP), packing into; The radial bearing portion and the supporting axis parts of (rotatably) rotate thrust bearing division freely at thrust axis on force direction rotating freely in the radial direction to be provided with the supporting axis parts, on the radial axle parts, use at least on bearing surface, to have the hydraulic bearing of dynamic pressure generation with ditch (dynamic-pressure generating grooves).The dynamic pressure ditch of radial bearing portion is formed at arbitrary side wherein of outer circumferential face of inner peripheral surface or the spindle unit of bearing sleeve.
Usually, the bearing sleeve utilization is pressed into the interior week that is fixed on case with means such as bonding, drains to the outside in order to prevent at the inner lubricant oil that injects of case in addition, and how the opening portions at case set sealed member.
The hydrodynamic bearing device of above-mentioned formation is made up of these parts of case, bearing sleeve, spindle unit and sealed member; In order to ensure the accompanying information machine increasingly high performance and become necessary high bearing performance, make great efforts to improve the machining accuracy and assembling validity of each parts.On the other hand, be accompanied by the tendency of the low price of information machine, the requirement that reduces cost of this kind hydrodynamic bearing device is also become more urgent.
The object of the invention is exactly that the cost of seeking this kind hydrodynamic bearing device reduces.
Other purpose of the present invention is to improve the shaping validity and the function property of the case of this kind hydrodynamic bearing device.
Other purpose of the present invention is in this kind hydrodynamic bearing device, to obtain in the more stable bearing performance, and the machining accuracy of case and assembling validity are improved.
Other purpose of the present invention provides portion's article number of packages few, more low cost and the high hydrodynamic bearing device of reliability.
Summary of the invention
In order to reach above-mentioned purpose; The present invention provides a kind of case in hydrodynamic bearing device for forming at the crystalline resin combination more than 20% through degree of crystallinity; Form between the periphery of the spindle unit that this hydrodynamic bearing device is included in and should supports the radial bearing device bearing sleeve, make bearing sleeve be fixed in the case in week; When the relative rotation of spindle unit and bearing sleeve, the oil film that forms through the radial bearing gap is at non-contact supporting axis parts and bearing sleeve in the radial direction.Resinous case can be shaped by models such as encapsulation moldings and form, thus with the metallic case that utilizes machining such as rotary cut mutually specific energy make with low cost, compare the validity that can guarantee than higher with metallic cases such as utilizing punching press simultaneously.
In above-mentioned formation, case also can be the molten resin that applies a plurality of parts and form.
Resin system case can be with bearing sleeves such as for example sintering metal systems as mosaic component, through resin mould is formed.Make case become the integrally formed article that are made up of sealed department, main part and bottom this moment, and the shaping of having cut down portion's article number of packages and can carry out case simultaneously and bearing sleeve are fixed to case, so on the reduction the number of working processes, be favourable.On the other hand; In this formation; Because case is the complicated shape of being made up of sealed department, main part and bottom; And on the shrinkage of resin, have reasons such as difference, so there is the shrinkage homogeneous that is difficult to make resin, be difficult to guarantee the situation of the shaping validity of case with the contact segment and the non-contact part of bearing sleeve such as sintering metal system.Although the desired function of each of these cases of sealed department, main part and bottom is different, because each one is formed by same resin combination, so be difficult to sometimes make the function that requires of each one be able to satisfy with higher level.
Through making case apply the resin that a plurality of parts form for molten, availablely possess, form, the resin combination of shape etc. by the material that requires function of corresponding each one respectively, each one of case is shaped.And make up through case each several part simple shape, the case of the complicated shape that can be shaped, and corresponding and bearing sleeve contact have or not, also can make each several part is other parts.Therefore, the shrinkage in the time of can making hardening of resin is in each homogenization, the pinpoint accuracyization that can seek case.
At this moment,, then can select to use, can seek the function property raising of case the optimal resin combination of function upon request if utilize the resin combination differ from one another to form a plurality of parts.At this moment, be common if make the material resin of different resin combinations, then can be when guaranteeing enough bond strengths, the operability when improving molten applying.
Case can be to be possessed a terminal bottom that two open-ended cylindrical main body portions, inaccessible main part are arranged, is located at another end of main part button, and forms the formation of the sealed department of seal clearance between the periphery of spindle unit.Through at case sealed department being set like this, with original such will other sealed department be pressed into another that be adhered to case terminal in the occasion in week compare, can reduction portion article number of packages, the while can reduce the number of working processes, and reaches cost degradation.
In addition; Case can be respectively parts through making main part, sealed department and bottom; And apply these parts are molten each other, or through main part is integrally formed in advance as parts with bottom and sealed department arbitrary side wherein, and with its and another molten deposited with shaping.
No matter be which kind of situation, main part can carry out mold forming as mosaic component with bearing sleeve at least.The fixed operation of bearing sleeve and the forming operation of case are carried out simultaneously, be able to seek the reduction of the number of working processes.
Each desired function of main part, sealed department and bottom is different, selects to use suitable its to require function so the resin combination of each one that is shaped is preferably.
For example, main part needs to keep for a long time the high tenacity of validity.Therefore, main part is preferably that resin combination by fusion reinforcing material in as the thermoplastic resin of material resin forms.
Friction when the bottom is asked to alleviate and contact with spindle unit and friction are resisted.Therefore, the bottom be preferably by in as the thermoplastic resin of material resin fusion fixedly the resin combination of oiling agent form.
In addition, sealed department is supposed to prevent really from the leakage of oil in the case with from the intrusion of moisture of outside etc.Therefore, sealed department is preferably by using thermoplastic resin as material resin, the wrapping angle of water formed at the resin combination more than 80 °.
The hydrodynamic bearing device that constitutes by thrust bearing division downside terminal surface of supporting axis parts on thrust direction of the bottom of being located at case; Pressure at the peripheral lubricating fluid of thrust bearing division improves, sometimes the pressure difference of the lubricating fluid of generation and seal perimeter.Because this pressure difference, produce local negative pressure in the lubricating fluid in the inner space of case, in lubricating fluid, generate bubble, become sometimes and result from this reason of the generation that spills and vibrate etc. of lubricating fluid.And the pressure of the lubricating fluid through thrust bearing division periphery improves, and produces the spindle unit come-up sometimes.Connection ditch through setting is communicated with thrust bearing division and sealed department can address this is that.Promptly; When the pressure at the peripheral lubricating fluid of thrust bearing division improves; Produce from the thrust bearing division periphery to the flowing of the lubricating fluid of sealed department periphery through the circulation ditch, make the thrust bearing division periphery and the pressure of the lubricating fluid of sealed department periphery keep equipressure whereby.
This circulation ditch can be made up of the second radial direction ditch between another terminal surface of axle direction ditch, the inner side surface of being located at sealed department and bearing sleeve between the outer circumferential face of the first radial direction ditch, the inner peripheral surface of being located at case and bearing sleeve between the terminal terminal surface of the bottom of for example being located at case and bearing sleeve.
Have the resin combination of the degree of crystallinity more than 20% to form case through utilization, then the lubricant oil as lubricating fluid is difficult to sucked by case.Therefore the amount of keeping the lubricant oil of supplying with case can be stabilized, long-term high bearing performance can be kept.
Become the sintering metal of bearing sleeve raw material, can metallic dust mixing, shaping, the sintering of porous metal be obtained it.This kind sintering metal is when inside has a plurality of pores (as the pore of porosity soma), and these pores possess a plurality of perforates that form through outer surface are arranged.As this metallic dust, can add powder or their alloy powders such as tin, zinc, graphite, molybdenum disulfide as required from for example selecting more than one powder to make raw material copper, iron and the aluminium.The bearing sleeve of this sintering metal system uses under with oil impregnated state.
The water absorption rate of this resin combination is preferably below 0.5%.
The linear expansion coeffcient of this resin combination is preferably 5 * 10
-5/ ℃ below.
If to 100 weight portions of this resin combination, the reinforcing material of fusion 10～80 weight portions then can improve the intensity of case, avoids dynamic pressure ditch validity low of the distortion through case.
In addition, at thrust direction supporting axis parts, the oil film that forms in the thrust-bearing gap also capable of using is in thrust direction non-contact supporting axis parts, or the bottom that utilizes case is at thrust direction contact supporting axis parts.
When the bottom that utilizes case during,, be preferably 100 weight portions, the solid lubricant of fusion 5～30 weight portions to this crystalline resin composition in order to alleviate frictional force at contacting part at thrust direction contact supporting axis parts.
Above-mentioned each case can be through forming bearing sleeve as the mosaic component contour forming.
And; The present invention provides a kind of hydrodynamic bearing device in order to reach purpose; This device be included in an end side have the bottom resinous case, be located at the inside of case metal bearing sleeve, insert between the outer circumferential face of spindle unit, the inner peripheral surface of being located at bearing sleeve and spindle unit of inner peripheral surface of bearing sleeve; The oil film of the lubricant oil that produces by the bearing play in the radial bearing portion of radial direction non-contact supporting axis parts, be located at the bottom of case, at the thrust bearing division of a terminal terminal surface of thrust direction supporting axis parts; Case with bearing sleeve as mosaic component; Degree of crystallinity is formed at the crystalline resin combination mold forming more than 20%; Bearing sleeve at least interior Monday end side chamfered section is partly arranged, and apply the anti-means of peeling off of peeling off that prevent and constitute the resin of case in this chamfered section.
Through making the resin mold moulding form case as mosaic component bearing sleeve, compare with the situation of utilizing metallic material to form case, can reduce the manufacture cost of case.And thrust bearing division can adopt the structure by a terminal terminal surface of the direct supporting axis parts in the bottom of case, so do not need the original the sort of thrust plate of being located at hydrodynamic bearing device, can seek the reduction of portion's article number of packages.In addition, because need be to the assembling operation of the bearing sleeve of case, so assembly cost also reduces.
Usually interior all two ends (bight) at bearing sleeve are provided with chamfered section; But the chamfered section of interior Monday of bearing sleeve terminal (bight of case bottom) particularly; When case and bearing sleeve being inlayed when being shaped; Terminal and be installed on required spatial volume between the interior type of bearing sleeve inner peripheral surface with guaranteeing in interior Monday of bearing sleeve, prevent that filling from partly being the effect of fine burr in the resin of this slit portion.On the other hand; Resin shrinkage when following melting resin in the former of forming die, to solidify; Resin in the bottom that constitutes case partly produces the internal stress to internal side diameter, this internal stress from the interior Monday of bearing sleeve terminal chamfered section to the directive effect of peeling off resin.In view of this; The present invention passes through in the terminal chamfered section interior Monday of bearing sleeve; Apply prevent with the resin that constitutes case peel off peel off the means of preventing; Can avoid resin and peel off and produce the state of affairs of not satisfied influence, improve the reliability of hydrodynamic bearing device in bearing performance from this chamfered section.
This peels off the means of preventing for example is can be through when forming bearing sleeve with sintering metal, and the percent opening that makes terminal chamfered section Monday in it constitutes greater than the percent opening of inner peripheral surface.
As this sintering metal; Availablely from for example copper, iron and aluminium, select metallic dust or copper lining iron powder etc. more than a kind to impose metallic dust that lining handles and alloy powder as main material; Mix powder or their alloy powders such as tin, zinc, graphite, molybdenum disulfide as required, and form, sintering obtains.This sintering metal has in a plurality of pores (as the pore of porosity soma) in inside, also has a plurality of perforates (porous gonosome) that these pores communicate with outer surface and form.
After making case by the resin mold moulding as mosaic component the bearing sleeve of sintering metal system; Melting resin follows a kind of anchor formula fixed effect that resin is bonded on this surface securely from invading in the pore of skin section in the face of the perforate on the surface of the bearing sleeve in the former of forming die and solidifying.Then, the percent opening through making this chamfered section can improve the above-mentioned anchor formula fixed effect of this chamfered section more greater than the percent opening of inner peripheral surface, effectively prevents resin peeling off from this chamfered section.In addition, the setting of this percent opening is not only applicable to this chamfered section, is applicable to other surface of the bearing sleeve of resin-bonding, for example outer surface and terminal surface yet.
This " percent opening " is meant the shared ratio of summation (gross area) of the area of each perforate on per unit area, measures with following condition.
[mensuration utensil]
Metallurgical microscopes: Nikon ECLIPSS ME600
Digital camera: Nikon DXM1200
Shooting photography software: Nikon ACT-1ver.1
Image processing software: ENOTECK system QUICK GRAIN
[condition determination]
Shooting photography: shutter speed 0.5 second
Binary-state threshold: 235
Perhaps; This peels off the means of preventing can be through when forming bearing sleeve with common metallic material (though the metallic material of inorganization property pore or organized pore but the little metallic material of the porosity), and the surface roughness of the chamfered section of end Monday in it is constituted greater than the surface roughness of inner peripheral surface.As this metallic material, can use for example stainless steel, Cuprum alloy, brass etc.
Surface roughness through making this chamfered section is greater than the surface roughness of inner peripheral surface, and when case was shaped, melting resin was invaded the small recess in the surface roughness and solidified, and follows a kind of anchor formula fixed effect to make resin be bonded in the surface of this chamfered section securely.Can effectively prevent resin peeling off whereby from this chamfered section.In addition, the setting of this surface roughness is not only applicable to this chamfered section, is applicable to other surface of the bearing sleeve of resin-bonding, for example outer surface and terminal surface yet.
Peel off and prevent effect in order to improve this more, can recess be set in this chamfered section.This recess can be for example ditch shape, nick shaped, pit shape.Through recess being set in this chamfered section, make bond area increase to the resin of this chamfered section, this is peeled off and prevents that effect from further improving as a result.And, also help above-mentioned peeling off to prevent in the combination force of above-mentioned basic upper recess and resin sometimes according to the form of recess.
And the present invention is in order to reach above-mentioned purpose; A kind of hydrodynamic bearing device is provided; This device be included in an end side have the bottom resinous case, be located at the inside of case metal bearing sleeve, insert between the outer circumferential face of spindle unit, the inner peripheral surface of being located at bearing sleeve and spindle unit of inner peripheral surface of bearing sleeve; The oil film of the lubricant oil that produces by the bearing play in the radial bearing portion of radial direction non-contact supporting axis parts, be located at the bottom of case, at the thrust bearing division of a terminal terminal surface of thrust direction supporting axis parts; Case as mosaic component, makes degree of crystallinity form at the crystalline resin combination mold forming more than 20% bearing sleeve.
When case was shaped, interior Monday of bearing sleeve, clearance portion terminal and that be installed between the interior type of bearing sleeve inner peripheral surface utilized base member to carry out obturation, so not filling of melting resin is in this clearance portion.Therefore, interior Monday of the end of bearing sleeve does not contact with resin, and the problem of peeling off from the resin of this part does not take place.
In above formation, bearing portion can be the lubricant oil that makes in the bearing play and produces the hydraulic bearing of dynamic pressure.And, drain to the outside in order to prevent the lubricant oil that injects in the inner space of case, at another end of case, will and the outer circumferential face of spindle unit between form seal clearance sealed department be integrally formed to preferable.
Description of drawings
Fig. 1 is to use the sectional view of the information machine of hydrodynamic bearing device with spindle drive motor.
Shown in Figure 2 is the 1st embodiment's of the present invention sectional view.
Shown in Figure 3 is the 2nd embodiment's of the present invention sectional view.
Shown in Figure 4 is the 3rd embodiment's of the present invention sectional view.
Shown in Figure 5 is the 4th embodiment's of the present invention sectional view.
Shown in Figure 6 is the 5th embodiment's of the present invention sectional view.
Shown in Figure 7 is the 6th embodiment's of the present invention sectional view.
Shown in Figure 8 is the 7th embodiment's of the present invention sectional view.
Shown in Figure 9ly be sectional view at the injection moulding device of the conceptive case that is used to be shaped.
Shown in Figure 10 is sectional view about the chamfered section periphery of the 8th embodiment's of the present invention bearing sleeve.
Shown in Figure 11 is sectional view about the chamfered section periphery of the 9th embodiment's of the present invention bearing sleeve.
Shown in Figure 12 is sectional view about the chamfered section periphery of the 10th embodiment's of the present invention bearing sleeve.
Shown in Figure 13 is the 11st embodiment's of the present invention sectional view.
Shown in Figure 14 is the 12nd embodiment's of the present invention sectional view.
Shown in Figure 15 is the 13rd embodiment's of the present invention sectional view.
Embodiment
Following one side is explained embodiments of the invention with reference to the diagram one side.
Shown in Figure 1ly constitute routine with one of spindle drive motor for the information machine of packing into about embodiment's hydrodynamic bearing device 1.This spindle drive motor is used for disk drives such as HDD, possesses the hydrodynamic bearing device 1 that rotates non-contact supporting axis parts 2 freely, the disk wheel hub 3 that is installed on spindle unit 2, the motor stator 4 and the motor rotor 5 of subtend through the gap of radial direction are arranged.Stator 4 is installed on the periphery of sleeve pipe 6, and rotor 5 is installed on the interior week of disk wheel hub 3.The case 7 of hydrodynamic bearing device 1 is installed on the interior week of sleeve pipe 6.Maintain disc D such as one or more pieces disks in the disk wheel hub 3.After stator 4 energising, make rotor 5 rotations by the excitatory power of 5 of stator 4 and rotors, make disk wheel hub 3 and spindle unit 2 be integral rotation whereby.Can use arbitrary embodiment's of following explanation bearing means as hydrodynamic bearing device 1.
Shown in Figure 1 is the 1st embodiment.This embodiment's hydrodynamic bearing device 1 is to utilize the dynamic pressure ditch to make to produce the Hydrodynamic bearing device (fluid dynamic bearing) of the dynamic pressure of lubricant oil with the supporting axis parts in the bearing play.
This Hydrodynamic bearing apparatus 1 is with an end openings, and the case that bottom tube-like is arranged 7 of another tip occlusion, bearing sleeve cylindraceous 8, spindle unit 2 constitute for the main composition parts.
Between the outer circumferential face 2a of the inner peripheral surface 8a of bearing sleeve 8 and spindle unit 2, first R1 of radial bearing portion and the 2nd R2 of radial bearing portion axially isolate setting.And, between the inner peripheral surface 7c1 of the bottom 7c of the downside terminal surface 2b of spindle unit 2 and case 7, be provided with thrust bearing division T.In addition, for the facility of explaining, be downside with thrust bearing division T side, otherwise with thrust T mutually side be that upside launches explanation.
On the inner peripheral surface 8a of bearing sleeve, on axle direction, isolate setting as two zones of each radial bearing surface of first R1 of radial bearing portion and second R2 of radial bearing portion, be formed with the for example dynamic pressure ditch of herringbone shape on these two zones respectively.In addition, as the shape of dynamic pressure ditch, also can adopt spirality and axle direction ditch shape etc.On the upside terminal surface 8b of bearing sleeve 8, be formed with the ditch 8e of the directivity that is used to discern bearing sleeve 8 in the form of a ring.
Inner peripheral surface 7b1 straight-line extension on axle direction of the inner peripheral surface 7a1 of sealed department 7a and main part 7b, the inner peripheral surface 7a1 of sealed department 7a is relative with the cone seal gap S that outer circumferential face in the taper of spindle unit 2 formation passes through institute's Fixed width degree.In case 7, the outer circumferential face 8g of the upside terminal surface 8b of the inner side surface 7a2 of sealed department 7a and bearing sleeve 8, the inner peripheral surface 7b1 of main part 7b and bearing sleeve 8, the inner bottom surface 7c1 of bottom 7c and the downside terminal surface 8c of bearing sleeve 8 are bonded together respectively.
In addition, the chamfered section 8d that forms in interior week at the upside terminal surface 8b of bearing sleeve 8 is not covered by resin.Therefore, if for example on this chamfered section 8d, form this ditch 8e in the form of a ring, then, case 7 also can differentiate the directivity of bearing sleeve 8 after being shaped from the outside.In addition, even form the occasion of ditch 8e, the 7a of sealed department at least in the case 7 is formed also by transparent resin can obtain same effect at upside terminal surface 8b.
When spindle unit 2 and bearing sleeve 8 (being spindle unit 2 rotations in the present embodiment) during rotation relatively, as the zone (zone, two places up and down) of the radial bearing surface of the inner peripheral surface 8a of bearing sleeve 8, with the outer circumferential face 2a of each spindle unit 2 through radial bearing gap subtend.Then, follow the rotation of spindle unit 2, form the oil film of lubricant oil in the radial bearing gap, make spindle unit 2 be rotated non-contact support freely in the radial direction by its dynamic pressure.Whereby, first R1 of radial bearing portion and the 2nd R2 of radial bearing portion of non-contact supporting axis parts 2 are configured rotating freely in the radial direction.On the other hand, spindle unit 2 utilizes the thrust bearing division T of pintle type on thrust direction, to be rotated support freely.
As stated, this embodiment is shaped the cup part of main part 7b and bottom 7c formation in advance as parts, then through the molten sealed department 7a that applies as other parts on these parts, formation case 7.Whereby, the shape of each parts is by simpleization, so can make each 7a of the～7c pinpoint accuracy of case 7 be shaped the pinpoint accuracyization that can seek case 7.And sealed department 7a can be formed by the resin combination of the characteristic that meets its function (sealing function), thus can improve sealing, prevent unchangeably for a long time in the case 7 oil spill and from the intrusion of the foreign matter (water etc.) of outside.
As the resin combination that is imbued with sealing, can be resin combination with non-adhesive.This be wrapping angle to water at the resin combination more than 80 °, the resin combination that satisfies this condition not only is imbued with water proofing property and also is imbued with grease proofness, so can positively prevent the immersion of moisture and spilling of oil from the outside for a long time.As this resin combination, can be for example vistanexes such as fusion polyfurolresin, PE such as PFA.In addition, through with any (or more than two kinds) fusion of PTFE, this fusion polyfurolresin, this vistanex thermoplastic resin (particularly engineering plastics), the non-adhesive resin combination that can obtain having same characteristic as material resin.In addition, the material resin as this moment can use polyamide resin, PPS (polyphenylene sulfide resin), LCP (liquid crystal polymer resin) etc.
The 2nd embodiment shown in Figure 3 is different with the 1st embodiment, is that the cup part of sealed department 7a and main part 7b formation is integrally formed in advance as parts.After inlaying shaping,,, form case through melting other parts (bottom 7c) of the molten deposited other making of means such as applying with ultrasonic wave at the downside terminal surface of main part 7b.
At this moment, the good resin combination of available antifriction consumption and self lubricity forms bottom 7c, can reduce the friction of thrust bearing division T whereby, reduces the friction to bottom 7c, can seek the low distanceization of changeing simultaneously.Can be fusion as this resin combination with solid lubricants such as PTFE, graphite, molybdenum disulfide and thermoplastic resin (particularly engineering plastics).Thermoplastic resin as this occasion uses PPS, LCP etc. ideal.
The 3rd embodiment shown in Figure 4 is not shaped the each several part of sealed department 7a, main part 7b and the bottom 7c of case 7 as parts, through with they molten each other applying, case 7 is shaped.After making main part 7b inlay shaping as mosaic component the bearing sleeve 8, wait molten respectively sealed department 7a and the bottom 7c that makes in addition that apply through molten the applying of ultrasonic wave, case 7 is shaped through downside terminal surface above that.
At this moment, capable of using have the resin combination of high accuracy to size to form main part 7b, improves the validity of case 7 (particularly main part 7b) whereby, and inhibition can be kept dynamic pressure ditch validity based on the distortion of the bearing 8 of the error of case 7.As this resin combination, can be the fusion of the for example fibrous reinforcing material of reinforcing material (glass fibre etc.), palpus crystalline reinforcing material (potassium titanate etc.) or flakey reinforcing material (mica etc.) with thermoplastic resin (particularly engineering plastics).Use PPS, LCP etc. ideal as thermoplastic resin.
The 4th embodiment shown in Figure 5 and the 3rd embodiment the upper and lower sides terminal surface of main part 7b molten respectively apply sealed department 7a and bottom 7c relative, be at molten sealed department 7a of applying of the upper and lower sides inner peripheral surface of main part and bottom 7c.Identical point except this with the 3rd embodiment, so omit repeat specification.
The 5th embodiment shown in Figure 6 also can be described as the compound of the 3rd embodiment and the 4th embodiment; Be at the upside end of sealed department 7a, bottom 7c, main part 7b and downside the end section of formation 7a3,7c3,7b3,7b4 respectively; So that the 7a3 of section portion of sealed department 7a is bonded in the terminal 7b3 of section portion of upside of main part 7b; Make the 7c3 of section portion of bottom 7c be bonded in the state of the terminal 7b4 of section portion of the downside of main part 7b simultaneously, it is deposited that these parts are melted each other.In addition, a sealed department 7a and bottom 7c side wherein also can with the 3rd embodiment and the 4th form that embodiment is same under melt and apply.
When so molten each 7a of that applies case, 7b, 7c, through forming molten each parts that apply with the resin combination identical earlier, make firm molten applying become possibility, and can improve the operability that melts when deposited with material resin.For example when using with LCP as the resin combination of material resin at main part 7b, sealed department 7a and bottom 7c also can be in order to the resin combination formation of LCP as material resin.
In addition, LCP has liquid crystal liquid crystal property stiffening effect (adding epistasis certainly) and the reduction friction effect is arranged after sclerosis, so even not fusion reinforcing material and solid lubricant himself also have the good rub resistance and the characteristic of pinpoint accuracy property.Therefore, also can only form each 7a～7c of of case, also become possibility by the resin combination shaping case 7 of single kind by LCP.And LCP has low degasification property, so as forming case 7 by LCP, the spindle drive motor of then using as the HDD device of abstaining from this degasification property generation becomes more suitable with bearing.
The 6th embodiment shown in Figure 7 utilizes connection ditch 10 that the seal clearance S of thrust bearing division T and sealed department 7a is communicated with.In this embodiment, being communicated with the first radial direction ditch 10a that ditch 10 forms by the downside terminal surface 8c at bearing sleeve 8, the axle direction ditch 10b that forms at the outer circumferential face of bearing sleeve 8, the second radial direction ditch 10c that forms at the upside terminal surface 8b of bearing sleeve 8 constitutes.In addition, the first radial direction ditch 10a also can be formed at the inner bottom surface 7c1 of the bottom 7c of case 7, and axle direction ditch 10b also can be formed at the inner peripheral surface 7b1 of the main part 7b of case 7, and the second radial direction ditch 10c also can be formed at the inner side surface 7a2 of sealed department 7a.
When spindle unit 2 rotations; After the pressure of the lubricant oil of the periphery of thrust bearing division T increases; Through being communicated with ditch 10; Generation to the flowing of the lubricant oil of the periphery of seal clearance S, makes the pressure of lubricant oil of periphery of periphery and the seal clearance S of thrust bearing division T keep equipressure from the periphery of thrust bearing division T by this.Therefore, can prevent to follow the generation of lubricant oil local negative pressure and generate bubble, and as the generation that spills and vibrate of the lubricating fluid of cause.And, improve through making pressure at the lubricant oil of the periphery of thrust bearing division T, also can prevent the come-up of spindle unit 2.
Fig. 8 is the hydrodynamic bearing device 11 of expression about the 7th embodiment.This hydrodynamic bearing device 11 constitutes case 7, bearing sleeve 8, spindle unit 2 as component parts.
Between the outer circumferential face 2a of the inner peripheral surface 8a of bearing sleeve 8 and spindle unit 2, first R1 of radial bearing portion and the 2nd R of radial bearing portion 2 axially isolate setting.And, between the inner bottom surface 7c1 of the bottom 7c of the downside terminal surface 2b of spindle unit 2 and case 7, be provided with thrust bearing division T.In addition, for the facility on explaining, be downside with thrust bearing division T side, otherwise with thrust T mutually side be that upside launches explanation.
In this embodiment; The percent opening of the inner peripheral surface 8a of bearing sleeve 8 for example is set at 0.5～10%, is preferably the value in 1～5% scope, and the setting of the chamfered section 8f of interior all lower ends is greater than the percent opening of inner peripheral surface 8a; For example be set at more than 3%, be preferably the value in 5～30% scopes.Upside terminal surface 8b, downside terminal surface 8c and outer circumferential face 8g wherein at least one surperficial percent opening also for the same value of chamfered section 8f be preferable, this embodiment surperficial percent opening that these are all is set at the value same with chamfered section 8f.The percent opening that interior week is gone up terminal chamfered section 8d also can be set at the value same with inner peripheral surface 8a, perhaps is set at the value same with chamfered section 8f.
Shown in Figure 9ly be device for injection forming at notional case 7 that is used to be shaped.This injection moulding device possesses internal mold 10 and external mold 20 is arranged, with two metal molds wherein any (for example internal mold 10) but be dynamic model, another (for example external mold 20) are fixed die.
In addition, when encapsulation molding, in advance bearing sleeve 8 is heated to the above temperature (for example more than 150 ℃) of mould temperature (about 100 ℃), the melting point of better is melting resin is above for preferable.The bearing sleeve 8 of when injection moulding, heating in advance like this becomes melting resin and is easy to invade in the pore of skin section from the surperficial perforate of bearing sleeve 8, can further improve this anchor formula fixed effect.
The Hydrodynamic bearing apparatus 11 of this example can be through to utilizing this case that interfixes 7 of inlaying shaping and bearing sleeve 8 installation shaft parts 2 to assemble.That is,, make the inner bottom surface 7c1 of its lower end contact case 7 with the inner peripheral surface 8a of spindle unit 2 insertion bearing sleeves 8.Then, injecting lubricant oil by the inner space of the case 7 of sealed department 7 ' a sealing.
When spindle unit 2 rotation, as the zone (zone, 2 places up and down) of the radial bearing surface of the inner peripheral surface 8a of bearing sleeve 8, respectively with the outer circumferential face 2a of spindle unit 2 through radial bearing gap subtend.Then, follow the rotation of spindle unit 2, the dynamic pressure that produces lubricant oil in this radial bearing gap, spindle unit 2 utilizes the oil film that is formed at the lubricant oil in the above-mentioned radial bearing gap, is being rotated non-contact support freely in the radial direction.Whereby, first R1 of radial bearing portion and the 2nd R2 of radial bearing portion of non-contact supporting axis parts 2 are configured rotating freely in the radial direction.Simultaneously, the downside terminal surface 2b of spindle unit 2 is contacted support through the inner bottom surface 7c1 of case 7.By this, on thrust direction, rotating freely, the thrust bearing division T of supporting axis parts 2 is configured.
Like Figure 10～embodiment shown in Figure 12, the effect of peeling off for the resin of the chamfered section 8f that further improves at bearing sleeve 8 is provided with concavity portion respectively at chamfered section 8f.The 8th embodiment shown in Figure 10 is circumferential groove 8f1 to be set as concavity portion in the zone of the downside terminal surface 8c through chamfered section 8f.In addition, the 10th embodiment shown in Figure 12 is radial direction ditch 8f3 to be set as concavity portion at downside terminal surface 8c to chamfered section 8f.This radial direction ditch 8f3 can be odd number, also can be located at a plurality of positions of circumferencial direction.
The 11st embodiment shown in Figure 13 is that 7c buries base member 9 such as metallic underground in the bottom of case 7.Base member 9 comprises the through hole 9a that is located at central part, from the axle collar 9b that outer periphery prolong to the upside one, its terminal surface is affixed on the downside terminal surface 8c of bearing sleeve 8, the inner face of axle collar 9b is affixed on the outer circumferential face 8g of bearing sleeve 8.Through hole 9a is filled with the resin that constitutes case 7, and the downside terminal surface 2b of spindle unit 2 contacts with the inner bottom surface 7c1 that utilizes the resin formation that is filled in through hole 9a, does not contact with base member 9.And the inner circumference edge of base member 9 prolongs to internal side diameter than the inner peripheral surface 8a of bearing sleeve 8 slightly, the state that becomes the chamfered section 8f of bearing part 8 to be capped from downside through base member 9 by this.
This embodiment's case 7 device for injection forming for example shown in Figure 9 capable of using are through forming the resin mold moulding as mosaic component bearing part 8 and base member 9.When the shaping of case 7, the clearance portion between the chamfered section 8f of bearing sleeve 8 and the internal mold 10 is inaccessible through base material 9 quilts, so melting resin is not filled in this clearance portion.Therefore, the chamfered section 8f of bearing sleeve 8 does not contact with resin, does not have the problem of peeling off from the resin of chamfered section 8f.
In addition, shown in the 12nd embodiment of Figure 14, base member 9 also can be the shape of not having through hole at central part.
And above embodiment forms bearing sleeve 8 with sintering metal, but metallic material such as also available stainless steel, Cuprum alloy, brass form the bearing sleeve of same form.As the means of preventing of peeling off of resin, the setting of carrying out surface roughness replaces the setting of this porosity when the time comes.That is the surface roughness of chamfered section (corresponding to chamfered section 8f) that, makes interior all lower sides of bearing sleeve is greater than the surface roughness of inner peripheral surface.For example, make the not enough Ra 0.5 of surface roughness of the inner peripheral surface of bearing sleeve, the surface roughness of the chamfered section of interior all lower sides is at Ra more than 0.5.The upside terminal surface of bearing sleeve, downside terminal surface and outer circumferential face be at least one surperficial surface roughness wherein, and it is preferable also getting same value with the chamfered section of interior all lower sides.
Shown in Figure 15 is hydrodynamic bearing device 21 about the 13rd embodiment.In this embodiment, bearing sleeve 8 can't help case 7 by casting mold.Bearing sleeve 8 is fixed in the interior week of the resin system case 7 that bottom tube-like is arranged of other shaping with means such as bonding, as to be pressed into.
And sealed department forms through the sealed member 10 with case 7 differences.Sealed member 10 both can also can be formed by metallic material by forming like above-mentioned resin combination.
After characteristic that the present inventor is asked resinous case 7 among the above embodiment and the most suitable condition that satisfies its characteristic were studied with keen determination, the result found following experience.
[low oil absorption]
As the characteristic of the resin combination that constitutes case 7, what at first be asked to is low oil absorption.Because case 7 has lubricant oil position contacting a plurality of and as lubricating fluid,, be difficult to make the bearing play to produce enough dynamic pressures so the lubricant oil in the case is not enough in case oil absorbency is big.
Should low oil absorption in order to satisfy, case 7 forms preferable with crystalline resin combination with certain above degree of crystallinity (ratio of amount that makes the correct crystal region of arranging of molecular chain rule is more than certain).More than certain, then the resin tissue becomes fine and closely woven, is difficult to be absorbed in the tissue so lubricant oil becomes like degree of crystallinity.As can be clear and definite,, then can satisfy the oil absorption that case 7 is asked as being resin combination with the degree of crystallinity more than 20% through detailed research.The heat of fusion that this degree of crystallinity is measured from utilizing differential scanning calorimetric measurement (DSC:Differential Scanning Calorimetry) is tried to achieve; This condition determination does; To the thaw temperature of resin temperature range, 5～10 ℃/min of warming velocity at-100 ℃ to+30 ℃.H ° of substitution following formula of heat of fusion Δ in the time of will measuring heat of fusion Δ Hm that the result tries to achieve and degree of crystallinity 100% by this can be asked this crystallinity Xc (%).
Xc(％)＝ΔHm/ΔH°×100
(for example " compile on macromolecule handbook basis " macromolecule association compiles can to use document as Δ H °; 1996, training wind shop or " Thermal Analysis " B.Wunderlich, 1990; AcademicPress) said value; For example nylon 66 is 46, and nylon 11 is 41.5, and PET is 26.9 (unit all is [KJ/mol]).In addition, proportion and the X-ray diffraction beyond the degree of crystallinity DSC also capable of using tried to achieve.
[low water absorbable]
Secondly as the characteristic of the resin combination that constitutes case 7, what be asked to is low water absorbable.In case water absorption rate is excessive, will there be the shortage dimensional stability, to the installation of the motor of the case difficulty that becomes, or change apart from becoming inappropriate situation such as big.Therefore, water absorption rate should be preferable as far as possible for a short time, and specifically, water absorption rate is below 0.5%, to be desirably below 0.1% most.This water absorption rate means the test according to JIS K7209 or ASTM D570 in addition, the water absorption rate when in 23 ℃ water, placing 24 hours (weight rate before and after the test).
[low linear expansion property]
Secondly as the characteristic of the resin combination that constitutes case 7, what be asked to is that linear expansion coeffcient is little.Case 7 can heat up through the heat that produces in the bearing movable, but in case swell increment when the time comes is big, the distortion that causes bearing sleeve 8 is arranged then, makes the low anxiety of validity of dynamic pressure ditch.In order to prevent this state of affairs, case 7 is that linear expansion coeffcient is 5 * 10 through the low resin combination of linear expansion coeffcient specifically
-5/ ℃ below resin combination and form ideal.
[high rigidity]
About case 7, needs improve its intensity and guarantee validity.From this point, reinforcing materials such as the resin combination fusion glass fibre of formation case 7, graphite fiber, potassium titanate are preferable.In a single day in order to improve intensity, more unreasonable the amount of reinforcing material is thinks, but too much will make the resin flow property of molten state low, and the operability in the resin cast engineering is low.And through the blended amount of reinforcing material, above-mentioned linear expansion coeffcient also can be affected.From these viewpoints, reinforcing material is to 100 weight portions of resin combination, the weight portion of fusion 10～80, and 15～40 the weight portion of being desirably most is ideal.
[low sliding]
The 7c in the bottom of case 7 as stated, the downside terminal surface 2a of spindle unit 2 directly slides, so as the characteristic of case 7, sliding friction is low for preferable.From this viewpoint, constitute the resin combination of case 7, to its fusion 5～30 weight portions of 100 weight portion, be desirably the solid lubricant of 5～20 weight portions most, for example graphite, PTFE or molybdenum disulfide are ideal.
In addition, as the resin combination that satisfies above characteristic, can be for example nylon 66.100 weight portions of 7 pairs of these nylon 66 of case for example can for example 30 weight portions of glass fibre and the 10 weight portions of PTFE be shaped through fusion.
The present invention is applicable to all Hydrodynamic bearing apparatus through resin combination shaping case, and the structure of shape of hood and bearing is not limited to illustrated example.The hydraulic bearing that the hydrodynamic that for example produces through the thrust-bearing gap carries out the non-contact support constitutes applicable too the present invention of device of thrust bearing division.
And the present invention is too applicable to the hydrodynamic bearing device that constitutes radial bearing portion through so-called positive circular journal bearing (bearing surface is the bearing of positive toroidal).
Claims (9)
1. hydrodynamic bearing device; Comprise: have at an end between the outer circumferential face of resinous case, the metal bearing sleeve of being located at the inside of this case, the spindle unit that inserts the inner peripheral surface of this bearing sleeve, the inner peripheral surface of being located at this bearing sleeve and this spindle unit of bottom; The oil film of the lubricant oil that produces through the bearing play in the radial bearing portion of this spindle unit of non-contact support in the radial direction, be located at the bottom of this case; On thrust direction, support the thrust bearing division of a distal end faces of this spindle unit, it is characterized in that:
This case makes the resin combination contour forming with this bearing sleeve as mosaic component and forms;
This bearing sleeve at least interior Monday end chamfered section is arranged, and this chamfered section apply prevent with the resin that constitutes case peel off peel off the means of preventing.
2. hydrodynamic bearing device as claimed in claim 1 is characterized in that: this is peeled off the percent opening of the means of preventing through when utilizing sintering metal to form this bearing sleeve, making this chamfered section and constitutes greater than the percent opening of this inner peripheral surface.
3. hydrodynamic bearing device as claimed in claim 1 is characterized in that: this is peeled off the surface roughness of the means of preventing through making this chamfered section and constitutes greater than the surface roughness of this inner peripheral surface.
4. hydrodynamic bearing device as claimed in claim 1 is characterized in that: be provided with concavity portion in this chamfered section.
5. hydrodynamic bearing device as claimed in claim 1 is characterized in that: this radial bearing portion is for producing the hydraulic bearing of dynamic pressure through the lubricant oil in this bearing play.
6. hydrodynamic bearing device as claimed in claim 1 is characterized in that: this case other end side have and the outer circumferential face of this spindle unit between form the sealed department of seal clearance.
7. hydrodynamic bearing device; Comprise: have at an end between the outer circumferential face of resinous case, the metal bearing sleeve of being located at the inside of this case, the spindle unit that inserts the inner peripheral surface of this bearing sleeve, the inner peripheral surface of being located at this bearing sleeve and this spindle unit of bottom; The oil film of the lubricant oil that produces through the bearing play in the radial bearing portion of this spindle unit of non-contact support in the radial direction, be located at the bottom of this case; On thrust direction, support a distal end faces of this spindle unit thrust bearing division, be located at the bottom of this case; Cover interior Monday of the terminal base member of this bearing sleeve, it is characterized in that:
This base member comprises: be connected to the base portion of a distal end faces of this bearing sleeve, and the axle collar that is embedded in the outer circumferential face of this bearing sleeve, this axle collar from the outer periphery of this base portion towards axle direction one body extension,
This case makes the resin combination contour forming with this bearing sleeve and this base member as mosaic component and forms.
8. hydrodynamic bearing device as claimed in claim 7 is characterized in that: this radial bearing portion is for producing the hydraulic bearing of dynamic pressure through the lubricant oil in this bearing play.
9. hydrodynamic bearing device as claimed in claim 7 is characterized in that: this case other end side have and the outer circumferential face of this spindle unit between form the sealed department of seal clearance.
Applications Claiming Priority (12)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002-120619 | 2002-04-23 | ||
| JP2002120619 | 2002-04-23 | ||
| JP2002120619A JP3950990B2 (en) | 2002-04-23 | 2002-04-23 | Hydrodynamic bearing device |
| JP2002-157909 | 2002-05-30 | ||
| JP2002157909 | 2002-05-30 | ||
| JP2002157909 | 2002-05-30 | ||
| JP2002-164680 | 2002-06-05 | ||
| JP2002164680A JP3997113B2 (en) | 2002-06-05 | 2002-06-05 | Hydrodynamic bearing device |
| JP2002164680 | 2002-06-05 | ||
| JP2002275484A JP2004052999A (en) | 2002-05-30 | 2002-09-20 | Fluid bearing device |
| JP2002-275484 | 2002-09-20 | ||
| JP2002275484 | 2002-09-20 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031229174A Division CN100419287C (en) | 2002-04-23 | 2003-04-21 | Fluid bearing apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101245812A CN101245812A (en) | 2008-08-20 |
| CN101245812B true CN101245812B (en) | 2012-06-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008100850778A Expired - Lifetime CN101245812B (en) | 2002-04-23 | 2003-04-21 | Fluid bearing device |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP3950990B2 (en) |
| CN (1) | CN101245812B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4443915B2 (en) | 2003-12-24 | 2010-03-31 | Ｎｔｎ株式会社 | Hydrodynamic bearing device |
| JP4408788B2 (en) * | 2004-10-25 | 2010-02-03 | パナソニック株式会社 | Brushless motor and manufacturing method thereof |
| JP4837574B2 (en) * | 2007-01-12 | 2011-12-14 | Ｎｔｎ株式会社 | Hydrodynamic bearing device |
| JP5020652B2 (en) * | 2007-02-05 | 2012-09-05 | Ｎｔｎ株式会社 | Hydrodynamic bearing device |
| CN102192179A (en) * | 2010-03-18 | 2011-09-21 | 元山科技工业股份有限公司 | Method for manufacturing axle tube of radiating fan |
| JP6422755B2 (en) * | 2013-12-11 | 2018-11-14 | Ntn株式会社 | Fluid dynamic bearing device and motor including the same |
| CN103692170A (en) * | 2013-12-30 | 2014-04-02 | 浙江双飞无油轴承股份有限公司 | Method for manufacturing composite shaft sleeve with two tapered ends |
| JP7158815B2 (en) * | 2018-10-31 | 2022-10-24 | 株式会社ミツトヨ | rotary table device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5516212A (en) * | 1995-09-18 | 1996-05-14 | Western Digital Corporation | Hydrodynamic bearing with controlled lubricant pressure distribution |
| CN1209677A (en) * | 1997-08-26 | 1999-03-03 | 三星电机株式会社 | Brushless DC Motor |
-
2002
- 2002-04-23 JP JP2002120619A patent/JP3950990B2/en not_active Expired - Lifetime
-
2003
- 2003-04-21 CN CN2008100850778A patent/CN101245812B/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5516212A (en) * | 1995-09-18 | 1996-05-14 | Western Digital Corporation | Hydrodynamic bearing with controlled lubricant pressure distribution |
| CN1209677A (en) * | 1997-08-26 | 1999-03-03 | 三星电机株式会社 | Brushless DC Motor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101245812A (en) | 2008-08-20 |
| JP2003314555A (en) | 2003-11-06 |
| JP3950990B2 (en) | 2007-08-01 |
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Granted publication date: 20120620 |