JP2000312943A - Method and device for manufacturing workpiece having cylindrical face, and method and device for manufacturing dynamic pressure groove of fluid bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid occurrence of pitch displacement of a dynamic pressure groove formed on an inner hole of a bearing sleeve and deformation of the dynamic pressure groove. SOLUTION: This manufacturing device is constituted by forming a dynamic pressure groove 5 on an inner hole 2a of a bearing sleeve 2. In this case, the device comprises a hard ball holder 12 which rollably holds plural hard balls 13a and 13b for rolling the dynamic pressure groove 5 on the inner hole 2a, and a shaft member 11 which protrudably holds the hard balls 13a and 13b from the hard ball holder 12 towards the inner hole 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a workpiece having a cylindrical surface such as an inner cylindrical surface of a sleeve for a fluid bearing and an outer cylindrical surface of a rotary shaft supported by the sleeve, and an apparatus for manufacturing the same. More particularly, the present invention relates to a method and apparatus for manufacturing a dynamic pressure groove of a fluid bearing.

[0002]

2. Description of the Related Art A fluid bearing is disclosed, for example, in Japanese Patent Publication No. 4-783.
As shown in FIG. 1 of Japanese Patent Publication No. 64, a shaft having a dynamic pressure groove, a sleeve rotatably inserted around its outer periphery, a lubricant filled between the shaft and the sleeve, Consists of This fluid bearing is a non-contact bearing which generates pressure in the dynamic pressure groove by rotating either the shaft or the sleeve and thereby pumping the dynamic pressure groove. As disclosed in FIG. 3 of the above-mentioned publication, this fluid bearing manufacturing apparatus is composed of one kind of rotation mechanism and feed mechanism, and the equipment structure is simplified.

[0003]

However, the apparatus for manufacturing a dynamic pressure groove disclosed in Japanese Patent Publication No. 4-78364 requires only one kind of rotation mechanism and feed mechanism, and the apparatus structure is simplified. However, there is a problem that the processing jig cannot be removed unless the ball protruding from the guide pipe is returned along the groove after the formation of the dynamic pressure groove. Further, when the ball protruding from the guide pipe along the dynamic pressure groove is returned, there is a possibility that the pitch of the dynamic pressure groove is shifted or the dynamic pressure groove is deformed.

As described above, in the related art, since grooves with high precision cannot be formed, the dynamic pressure generated due to the variation in groove depth varies, causing rotation unevenness (jitter) or contact between the shaft and the sleeve, resulting in durability. There was a problem that it was inferior.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a workpiece having a cylindrical surface and an apparatus for manufacturing the same without causing a pitch shift of a groove formed in the cylindrical surface or deformation of the groove. And

Another object of the present invention is to provide a method and an apparatus for manufacturing a dynamic pressure groove of a fluid bearing which does not cause a pitch deviation of the dynamic pressure groove formed in the inner hole of the bearing sleeve and a deformation of the dynamic pressure groove. Its purpose is to provide.

[0007]

According to a first aspect of the present invention, there is provided an apparatus for manufacturing a workpiece having a cylindrical surface formed by engraving a groove in a cylindrical surface. A workpiece having a cylindrical surface including: a hard ball holder that rotatably holds a plurality of hard balls for rolling; and a rotating member that holds the hard balls so that the hard balls can be protruded and retracted from the hard ball holder toward the cylindrical surface. Manufacturing apparatus. In this configuration, since the grooves are formed by rolling, the occurrence of cuts is very small, and the processing time can be greatly reduced compared to cutting. It is also excellent. Further, since the hard sphere can be immersed, the groove can be formed by one-way processing, and a very high precision groove can be formed without causing a pitch shift of the groove formed on the cylindrical surface or a deformation of the groove. be able to.

According to a second aspect of the present invention, there is provided a method for manufacturing a workpiece having a cylindrical surface formed by engraving a groove in a cylindrical surface, wherein a plurality of hard balls are rollably held by a hard ball holder. In a state in which the hard sphere is projected from the hard sphere holder surface toward the cylindrical surface, a groove is rolled in the cylindrical surface, and after the groove is formed, the hard sphere is immersed from the hard sphere holder surface. A method for manufacturing a workpiece having a cylindrical surface, comprising releasing the hard sphere holder and the hard sphere along an axial direction of the cylindrical surface. In this configuration, since the grooves are formed by rolling, the occurrence of cuts is very small, and the processing time can be greatly reduced compared to cutting. It is also excellent. Further, since the hard sphere can be immersed, the groove can be formed by one-way processing, and a very high precision groove can be formed without causing a pitch shift of the groove formed on the cylindrical surface or a deformation of the groove. be able to.

According to a third aspect of the present invention, there is provided a fluid dynamic bearing having a bearing sleeve in which a dynamic pressure groove is formed in an inner hole, and a shaft inserted into the inner hole. And a plurality of hard balls are allowed to roll freely, and the tangent diameter of the hard balls is slightly larger than the inner diameter of the grooved portion of the fluid bearing sleeve. And a machining state in which the tangent diameter of the hard sphere is slightly larger than the inner diameter of the grooved portion of the fluid bearing sleeve, and the tangent diameter of the hard sphere is larger than the inner diameter of the grooved portion of the fluid bearing sleeve. A switching means for switching between a slightly smaller withdrawn state, and in the processing state, the groove processing tool is inserted into the inner hole of the bearing sleeve, and the groove processing tool is rotated and fed in the axial direction. Giving the plurality of hard balls into the inner hole Then, a dynamic pressure groove is rolled on the inner peripheral surface of the bearing sleeve, and in the pulled-out state, the tangent diameter of the hard ball is slightly smaller than the inner diameter of the grooved portion of the fluid bearing sleeve by the switching means, and the bearing can be pulled out. A hydrodynamic groove manufacturing apparatus for a hydrodynamic bearing, characterized in that: In this configuration, since the dynamic pressure groove formed in the inner hole of the bearing sleeve is formed by rolling,
Since the generation of cuts is very small, the processing time can be greatly reduced as compared with the cutting processing, and since the metal fiber is not cut in the processed portion, the strength is excellent. Furthermore, since the hard spheres can be immersed, the dynamic pressure grooves can be formed by one-way processing, and the pitch of the dynamic pressure grooves formed on the cylindrical surface and the deformation of the dynamic pressure grooves do not occur. An accurate dynamic pressure groove can be formed.

According to a fourth aspect of the present invention, in the apparatus for manufacturing a dynamic pressure groove of a fluid bearing according to the third aspect, the groove processing tool is located at a position opposed to a plane orthogonal to an axis of the shaft member. It is characterized in that the groove processing tool is reversely rotated around a substantially central portion of the bearing sleeve to form a dynamic pressure groove having a shape in which the inclination direction is reversed. .

According to a fifth aspect of the present invention, in the manufacturing apparatus for a dynamic pressure groove of a fluid bearing according to the fourth aspect, the groove processing tool comprises a plurality of hard spheres arranged at a position opposite to each other at an equal pitch, and a shaft member. Are coaxially and rotatably mounted on the same plane perpendicular to the axial direction of the shaft.

According to a sixth aspect of the present invention, in the apparatus for manufacturing a dynamic pressure groove of a fluid bearing according to the third aspect, the shaft member of the groove machining tool has a tangential diameter of a plurality of hard spheres for a fluid bearing sleeve. And a shaft member is slid in a hard sphere holder to hold the hard sphere in the groove of the shaft member, and the tangent diameter of the hard sphere is for a fluid bearing. It is characterized in that it can be switched to a configuration in which it is held so as to be slightly smaller than the inner diameter of the grooved portion of the sleeve.

According to a seventh aspect of the present invention, in the apparatus for manufacturing a dynamic pressure groove of a fluid bearing according to the third aspect, the shaft member of the groove machining tool has a tangential diameter of a plurality of hard spheres for a fluid bearing sleeve. And a taper portion is provided in the hard sphere holding portion of the shaft member so that the tangent diameter of the hard sphere can be finely adjusted.

According to an eighth aspect of the present invention, in the apparatus for manufacturing a dynamic pressure groove of a fluid bearing according to the third aspect, at least the hard ball holding portion of the hard ball and the groove processing tool is made of a material harder than the fluid bearing sleeve. It is characterized by consisting of.

According to a ninth aspect of the present invention, in the hydrodynamic groove manufacturing apparatus of the third aspect, the depth of the dynamic pressure groove formed by the hard sphere of the groove processing tool is several micrometers. It is characterized by a depth of from about 10 to several microns.

According to a tenth aspect of the present invention, the dynamic pressure groove of a fluid bearing having a bearing sleeve in which a dynamic pressure groove is formed in an inner hole and a shaft inserted into the inner hole is manufactured. In the manufacturing method, the bearing sleeve is held by a sleeve fixing tool, a plurality of hard balls can be rolled freely by a groove processing tool, and the tangent diameter of the hard balls is slightly smaller than the inner diameter of the groove processing portion of the fluid bearing sleeve. Holding so as to be large, inserting the groove processing tool into the inner hole of the bearing sleeve, giving the groove processing tool a rotational motion and an axial feed, and biting the plurality of hard balls into the inner hole. After forming a dynamic pressure groove on the inner peripheral surface of the bearing sleeve and forming the dynamic pressure groove, the tangent diameter of the hard sphere is made slightly smaller than the inner diameter of the grooved portion of the fluid bearing sleeve by switching means. A hydrodynamic groove for a hydrodynamic bearing, characterized in that . In this configuration, since the dynamic pressure grooves formed in the inner hole of the bearing sleeve are formed by rolling, the occurrence of facets is very small, and the processing time can be significantly reduced compared to cutting, and Since there is no cutting of the metal fiber in the portion, the strength is also excellent. Furthermore, since the hard spheres can be immersed, the dynamic pressure grooves can be formed by one-way processing, and the pitch of the dynamic pressure grooves formed on the cylindrical surface and the deformation of the dynamic pressure grooves do not occur. An accurate dynamic pressure groove can be formed.

According to an eleventh aspect of the present invention, in the method for manufacturing a dynamic pressure groove of a fluid bearing according to the tenth aspect, the hard ball is capable of rolling to an opposing position on a plane orthogonal to the axis of the shaft member. The rotational machining direction of the groove processing tool having the shape described above is substantially the center of the boundary of the bearing sleeve, and the dynamic direction of the inclined direction is reversed.

According to a twelfth aspect of the present invention, in the method for manufacturing a dynamic pressure groove of a fluid bearing according to the tenth aspect, the dynamic pressure groove of the bearing sleeve comprises a plurality of groove groups having a constant inclination angle. In the case of the herringbone type, the groove processing tool coaxially and coaxially on the same plane orthogonal to the axial direction of the shaft member at a constant pitch at a position where a plurality of hard spheres corresponding to each groove of the groove group are opposed to each other. Rotational movement and axial feed are given to the groove processing tool, which is rotatably mounted, and the rotation direction is reversed around a substantially central portion of the bearing sleeve.

According to a thirteenth aspect of the present invention, in the method for manufacturing a hydrodynamic groove for a fluid bearing according to the tenth aspect, the hard sphere of the groove processing tool is formed by rolling the inner peripheral surface of the fluid bearing sleeve. It is characterized in that a dynamic pressure groove having a depth of several micrometers to several tens of micrometers is formed.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a view showing the entire structure of a hydrodynamic bearing manufactured by the method and the apparatus for manufacturing a hydrodynamic bearing hydrodynamic groove according to the first embodiment of the present invention.

As shown in FIG. 2, the fluid bearing 1 is filled in a bearing sleeve 2, a shaft 3 inserted into an inner hole 2 a thereof, and a gap 6 between the inner hole 2 a and the outer periphery of the shaft 3. And the like. A dynamic pressure groove 5 for generating dynamic pressure is formed in the inner hole 2 a of the bearing sleeve 2. The dynamic pressure groove 5 has an inclination angle opposite to that of the substantially central portion of the bearing sleeve 2. A thrust bearing 7 is fixed to the bearing sleeve 2 at the bottom of the shaft 3 by an auxiliary plate 8. Bearing sleeve 2
Or, by rotating the shaft 3, a pumping action is generated in the dynamic pressure groove 5, whereby a pressure is generated in the lubricant 4,
The shaft 3 is pivotally supported by the bearing sleeve 2 by this pressure.

The hydrodynamic groove 5 has a groove depth of several μm, and the hydrodynamic groove 1 of the above-described structure can be used as a high-precision function as a bearing by the method and the apparatus for manufacturing the hydrodynamic groove of the hydrodynamic bearing of the present invention. Can be achieved, the dynamic pressure groove 5 can be processed with high precision, and the dimensional variation can be kept to a minimum.

FIG. 3 is a diagram showing a bearing sleeve structure of a fluid bearing to which the method and the apparatus for producing a fluid bearing dynamic pressure groove according to the first embodiment of the present invention are applied. As shown in FIG. 3, the bearing sleeve 2 is formed of a hollow cylindrical body penetrating the inner hole 2a. A dynamic pressure groove 5 which is a groove having an inclined angle is formed in the inner hole 2a. The dynamic pressure groove 5 has a depth of several μm, and as described above, the dynamic pressure groove 5 has a tilt angle in a direction opposite to the substantially central portion of the bearing sleeve 2.

FIG. 4 is a view showing a groove processing tool for processing the dynamic pressure groove of the bearing sleeve, which is used in the method and the apparatus for manufacturing the dynamic pressure groove of the fluid bearing according to the first embodiment of the present invention. , (A) is a cross-sectional view, (B) is FIG.
FIG. 3 is a sectional view taken along line A. As shown in FIG. 4A, the groove processing tool 10 includes a shaft member 11, a hard ball holder 12, a hard ball 13 such as a superalloy steel ball, a slide knob 14 fixed to the shaft member 11, It comprises a sliding window 15 a provided in the hard ball holder 12, a hard ball reservoir 11 a provided on the tip side of the shaft member 11, and a shank portion 15.

As shown in FIGS. 4A and 4B, the hard ball 1
Reference numeral 3 is in contact with the outer periphery of the shaft member 11 on a plane orthogonal to the axial direction of the shaft member 11, and is positioned and supported by holder holes 12a provided at equal intervals in the hard ball holder 12. A circumferential crimp 16 is formed around the holder hole 12a so that the hard sphere 13 does not jump out of the holder hole 12a. The circumferential caulking 16 can prevent the hard ball 13 from jumping out and backlash. In this example, the hard sphere 13 is composed of two hard spheres 13a and 13b,
And the hard sphere 13b are arranged at opposing positions (equal intervals) on the same plane. In addition, the hard ball 13a and the hard ball 13
The tangent diameters of b (FIGS. 4A and 4B) are arranged at opposing positions (equal intervals) on the same plane. Further, the tangent diameter d of the hard ball 13a and the hard ball 13b (FIG. 4 (A),
(B)) is formed slightly larger than the inner diameter D of the inner hole 2a of the bearing sleeve 2 shown in FIG. That is, (d-D)
The value of / 2 substantially corresponds to the groove depth of the dynamic pressure groove 5. The groove processing tool 10 is made of a material having higher hardness than the bearing sleeve 2, and the hard ball 13 and the shaft member 11 are particularly formed to have high strength and high hardness.

FIG. 1 is an axial cross-sectional view for explaining a method and an apparatus for manufacturing a hydrodynamic bearing hydrodynamic groove according to a first embodiment of the present invention. As shown in FIG. 1, the hydrodynamic bearing groove manufacturing apparatus according to the present embodiment includes a sleeve fixing device 1 on a fixed side of the device, which cantileverly supports a bearing sleeve 2 as a workpiece.
7 and a groove processing tool 1 for processing the dynamic pressure groove 5 in the bearing sleeve 2
0. The grooving tool 10 includes a shaft member 11 having a hard ball reservoir 11a near a tip end thereof;
1 and a hard ball 13 held in a holder hole 12a of the hard ball holder 12 (in the present embodiment,
Hard balls 13a and 13b) and shank 1
5 is provided.

Next, a method of machining a dynamic pressure groove using the above-described groove machining tool will be described with reference to FIG. First, the bearing sleeve 2 is cantilevered by a sleeve fixture 17 on the fixed side of the device. The shaft member 11 of the grooving tool 10 and the tip side of the hard ball holder 12 are carried into the entrance side of the inner hole 2a of the bearing sleeve 2, and the grooving tool 10 is rotated at a rotation speed of W and inserted at a feed speed of V. Move to This allows
The hard spheres 13a and 13b of the groove processing tool 10 are pressed into the inner hole 2a side and bite to form a predetermined dynamic pressure groove 5. Note that the groove processing tool 10 rotates in the opposite direction from the position of the boundary (indicated by the line XX) substantially at the center of the bearing sleeve 2. That is, X-
The grooving tool rotates CW (clockwise) until reaching the X-ray, and CCW (counterclockwise) rotates after passing the X-X line. Thus, a herringbone-shaped dynamic pressure groove as shown in FIG. 1 is formed.

In this way, the groove processing tool 10 is
4A, when the groove processing tool 10 is removed from the bearing sleeve 2, the slide knob 1 shown in FIG.
4 is moved in the sliding window 15a to a position opposite to the position at the time of the groove processing, and the hard sphere 13 is dropped into the hard sphere pool 11a provided on the shaft member 11, and the hard sphere 13 is moved to the hard sphere 13 similarly to the state shown in FIG. After being lowered from the holder 12, the groove processing tool 10 is removed from the bearing sleeve 2.

According to this embodiment, the groove processing tool 10 for positioning and holding the hard ball 13 by the hard ball holder 12 and the shaft member 11 is inserted into the bearing sleeve 2 and the groove processing tool 10
The burr is not generated on the end face of the dynamic pressure groove 5 by a relatively simple rolling process that only applies forward and reverse rotation and feed to the dynamic pressure groove 5.
Of the bearing sleeve 2 can be formed without damaging the inner peripheral surface 2 a of the bearing sleeve 2. In addition, the groove processing tool 10 can be removed from the bearing sleeve 2 after the hard ball 13 has been lowered from the hard ball holder 12, and does not reciprocate in the dynamic pressure groove 5. Further, since the hard ball 13 does not touch the inner hole 2a of the bearing sleeve 2, the inside of the inner hole 2a is not damaged.

Furthermore, since the rolling process is used, the processing time can be significantly reduced as compared with the cutting process, and since there is no cutting of the metal fiber in the processed portion, the strength is excellent. is there.

Further, the hard balls 13a and 13b which can be rolled to the coaxial position on a plane orthogonal to the axial direction of the shaft member 11 of the groove processing tool 10 are pressed against the inner hole 2a of the bearing sleeve 2, and the groove processing tool 10 is pressed. Is given in a rotational motion and in the axial direction to form a dynamic pressure groove 5. In addition, since the dynamic pressure groove 5 is formed of a groove having a direction opposite to the inclination angle with the boundary substantially at the center of the bearing sleeve 2, the groove processing tool 10 is rotated in the reverse direction at the boundary.

As described above, the dynamic pressure groove 5 is processed by a simple method including the forward and reverse rotation of the groove processing tool and the feed operation, so that the processing time is reduced. In addition, hard balls 13a, 13b
Are held by the hard ball holder 12 and the shaft member 11 and are arranged at a coaxial position, so that it is possible to form the dynamic pressure groove 5 with high accuracy without variation.

The hydrodynamic groove 5 has a groove depth of several μm, and the hydrodynamic groove 1 having the above-described structure can be used as a high-precision function as a bearing by the method and apparatus for manufacturing a hydrodynamic groove of the hydrodynamic bearing of the present invention. Can be achieved, the dynamic pressure groove 5 can be processed with high precision, and the dimensional variation can be kept to a minimum.

FIG. 5 is a view showing a bearing sleeve structure of a fluid bearing to which a method and a device for manufacturing a fluid bearing dynamic pressure groove according to a second embodiment of the present invention are applied. It is a figure showing a bearing sleeve which has two sets of grooves. Although not clearly shown in FIG. 5, the inner diameter 22a of the bearing sleeve 22 has eight dynamic pressure grooves 25 per set.
Are formed. For convenience of explanation, those dynamic pressure grooves 25
Are dynamic pressure grooves 25a, 25b, 25c.

FIG. 6 is a partial sectional view showing a main part structure of a groove machining tool used in a method and an apparatus for manufacturing a hydrodynamic bearing groove according to a second embodiment of the present invention. Used to machine dynamic pressure grooves in Note that portions other than those illustrated are the same as those in FIG.

The dynamic pressure groove 25 having the structure shown in FIG. 5 is processed by the hard sphere 33 of the groove processing tool 30 shown in FIG. As shown in FIG. 6, the hard balls 33 correspond to the dynamic pressure grooves 25a, 25b and the like, and are hard balls 33a, 33b, 33c, 33d, 33, respectively.
e. The hard balls 33a and the like are arranged at an equal pitch at intervals of 45 degrees.

FIG. 7 shows a method of manufacturing a hydrodynamic bearing groove according to a second embodiment of the present invention, and when the grooving tool used in the apparatus has finished processing the hydrodynamic groove, removes the grooving tool from the bearing sleeve. It is a figure showing a method.

A slide knob (not shown) similar to the slide knob 14 shown in FIG. 4A is moved to a position opposite to the position at the time of the groove processing. A slide window (not shown) similar to the slide window 15a shown in FIG. As shown in FIG. 7, the hard ball 33 is moved to the hard ball pool 31a provided on the shaft member 31 as shown in FIG.
And the grooved tool 30 is removed from the bearing sleeve after the hard sphere 33 is lowered from the hard sphere holder 32.

According to the present embodiment, the groove processing tool 30 for positioning and holding the hard ball 33 by the hard ball holder 32 and the shaft member 31 is inserted into the bearing sleeve 22 before processing, and the groove processing tool 30 is rotated forward and reverse. By the relatively simple rolling process that only gives, no burr is generated on the end face of the dynamic pressure groove 25,
The cross-sectional shape of the dynamic pressure groove 25 has a smooth curved surface, allows the lubricant to flow easily, has high precision and has no variation,
The dynamic pressure groove 25 can be formed without damaging the inner peripheral surface 22a of the second.

FIG. 8 shows a method for manufacturing a hydrodynamic bearing hydrodynamic groove according to a second embodiment of the present invention and a hard ball 3 provided with a tapered portion 31b in a hard ball holding portion of a shaft member 31 used in the apparatus.
FIG. 3 is a diagram showing a configuration in which the tangent diameter d of No. 3 can be finely adjusted. When the rotational speed of the motor changes due to the fine adjustment of the tangent diameter d, the clearance is adjusted by changing the inner hole 2a of the shaft 3 and the bearing sleeve 2. At this time, the tangent diameter of the hard sphere is adjusted. Although d must be changed, since the tangent diameter can be finely adjusted by the tapered portion 31b, there is no need to newly manufacture a groove processing tool. Further, the cost of the equipment is reduced.

The groove machining tool 30 having the hard balls 33a, 33b and the like having the above-described structure is inserted into the bearing sleeve 2a, and forward and reverse rotation and feed operations are performed in the same manner as in the above-described embodiment. 2 sets of herringbone type dynamic pressure grooves 2
5a, 25b and the like can be formed. The same applies to the method of manufacturing the dynamic pressure groove 5 of the hydrodynamic bearing 1 of the above embodiment and the method of manufacturing the hydrodynamic groove of the present embodiment. In the above description, the number of hard spheres formed on the groove processing tool is two or eight, but is not limited to this.

FIG. 11 is a view showing a method of manufacturing a dynamic pressure groove of a fluid bearing according to a third embodiment of the present invention and the entire structure of a fluid bearing manufactured by the apparatus. As shown in FIG. 11, the fluid bearing 41 includes a bearing sleeve 42 and a shaft 43 inserted into an inner hole 42a thereof. This axis 4
A hard ball escape groove 43a is formed in 3 and a dynamic pressure groove 45 for generating a dynamic pressure is engraved on the outer periphery of the shaft 43. The dynamic pressure groove 4
Reference numeral 5 denotes a shaft whose inclination angle is opposite to the center of the shaft 43 as a boundary. By rotating the bearing sleeve 42 or the shaft 43, a pumping action occurs in the dynamic pressure groove 45,
As a result, pressure is generated in the fluid such as lubricant and air, and the pressure causes the shaft 43 to be pivotally supported by the bearing sleeve 42.

The dynamic pressure groove 45 has a depth of several μm.
According to the method and the apparatus for manufacturing the dynamic pressure groove of the fluid bearing of the present invention, the fluid bearing 41 having the above-described structure can perform a high-precision function as a bearing, the dynamic pressure groove 45 is processed with high precision, and In addition, variations in dimensions can be kept to a minimum.

FIG. 9 is a partial sectional view showing a method and an apparatus for manufacturing a dynamic pressure groove of a fluid bearing according to a third embodiment of the present invention. Use to As shown in FIG. 9, an apparatus for manufacturing a dynamic pressure groove of a fluid bearing according to this embodiment includes a shaft 43 which is a workpiece.
And a shaft processing tool 50 for processing a dynamic pressure groove on the shaft 43. The shaft processing tool 50 includes a cylindrical member 51 having a hard ball reservoir 58 near the tip of the inner circumference, a hard ball holder 52 that is slidably mounted in the cylindrical member 51 in the axial direction, and a holder hole 52a of the hard ball holder 52. And a hard sphere 53 to be held. The hard ball holder 52 includes a hard ball holder fixing screw 54,
It is attached to the cylindrical member 51 via a washer 55, a slide window 56, and a screw hole 57 so that the position can be adjusted in the axial direction.

Next, a method of machining a dynamic pressure groove using the above-described groove machining tool will be described with reference to FIG. First, the shaft 43 is cantilevered by a shaft fixture 67 on the fixed side of the apparatus. The distal end sides of the cylindrical member 51 and the hard ball holder 52 of the shaft processing tool 50 are carried into a position facing the front end of the shaft 43, and the shaft processing tool 50 is
, And is moved in the insertion direction at the feed speed of V. Thereby, the hard sphere 53 of the shaft processing tool 50 is pressed and bites into the outer periphery of the shaft 43, and a predetermined dynamic pressure groove 45 is formed. Note that the shaft processing tool 50 rotates in the opposite direction from a boundary located substantially at the center of the processed portion of the shaft 43, that is, the shaft processing tool 50 rotates clockwise until reaching the boundary. After, it rotates counterclockwise.
As a result, a herringbone type dynamic pressure groove as shown in FIG. 11 is formed.

As described above, the shaft processing tool 50 is
In order to remove the shaft processing tool 50 from the shaft 43 when the processing of Step 5 is completed, loosen the hard ball holder fixing screw 54 shown in FIG. Is moved in the sliding window 15a to the position shown in FIG. 10, and the hard sphere 53 is dropped into the hard sphere pool 48 provided on the cylindrical member 51 as shown in FIG. Withdraw 50 from shaft 43.

According to this embodiment, the shaft 43 is inserted into the shaft processing tool 50 for positioning and holding the hard ball 53 by the hard ball holder 52 and the cylindrical member 51, and only forward and reverse rotation and feed are given to the shaft processing tool 50. Due to the relatively simple rolling process, no burr is generated on the end face of the dynamic pressure groove 45, and the cross-sectional shape of the dynamic pressure groove 45 presents a smooth curved surface. The dynamic pressure groove 45 can be formed without variation and without damaging the outer peripheral surface of the shaft 43. Further, the shaft processing tool 50 can be pulled out from the shaft 43 after the hard ball 53 has been lowered from the hard ball holder 52, and does not reciprocate in the dynamic pressure groove 45. There is no hard sphere 53 around the shaft 43
But does not touch it, so that the outer periphery is not damaged.
The dynamic pressure groove 45 having the structure shown in FIG. 11 is processed by the hard sphere 53 of the shaft processing tool 50 shown in FIG. This hard ball 53
It corresponds to the dynamic pressure groove 45.

In the above rolling process, when deformation such as bulging occurs around the groove, finishing can be performed by burnishing described later. Next, burnishing of the inner peripheral surface of the bearing sleeve will be described with reference to FIGS.

FIG. 12 is a sectional view of the bearing bore machining apparatus, FIG. 13 is a sectional view showing a main part of the bearing bore machining apparatus, and FIG. 14 is a sectional view taken along line AA of FIG. , FIG.
5 is a sectional view of a bearing sleeve processed by the bearing inner diameter processing device.

As shown in FIG. 12, the bearing inner diameter machining apparatus includes a base 109, a chuck 110 which is provided on the base 109, and fixes the sleeve 2 of the bearing which is a workpiece, and which is mounted on the base 109. A first motor 111 that has a feed screw 111a and engages with the slider portion 113 to change the distance between the taper pin 107 and the sleeve 2; and a second motor that rotates either the taper pin 107 or the sleeve 2. 112 and a burnishing jig 106 having a roller guide 101 into which the taper pin 107 is inserted.
And a stopper 114 for regulating the descending position of the slider portion 113.

As shown in FIG. 13, the burnishing jig 1
Reference numeral 06 denotes a roller guide 101 having a plurality of guide grooves 101a, and a tapered roller 102 rotatably supported in the guide grooves 101a via positioning pins 103.
A steel ball holder 104 for supporting the roller guide 101; and a steel ball 105 held by the steel ball holder 104.
And The roller guide 101 of the burnishing jig 106 is rotatably supported on a chuck 110 (see FIG. 12) by a steel ball holder 104 and a steel ball 105.

The tapered pin 107 has a tapered portion 107a at a part thereof, which serves as a rolling center of the tapered roller 102, and moves in and out of the roller guide 101 in the U and D directions in FIG. The circumscribed circle can be adjusted over the entire length of the roller 102, and at the same time, the taper ratio is configured so that the circumscribed circle is the same over the entire length of the tapered roller 102. That is, the taper pin 107
And the taper ratio of the tapered roller 102 is set to 2: 1.

The operation of the bearing inner diameter machining apparatus configured as described above will be described with reference to FIGS. First, as shown in FIG. 12, the sleeve 2 is mounted at a predetermined position on the chuck 110. Next, as shown in FIG. 13, the tapered roller 1 of the burnishing jig 106 is used.
02 is inserted into the inner diameter of the sleeve 2. As shown in FIG. 12, the burnishing jig 106 is a steel ball holder 1.
04 and the steel ball 105 are rotatably installed on the upper surface of the chuck 110. As shown in FIG.
12 rotates the taper pin 107, and the first motor 11
When the taper pin 107 attached to the second motor 112 is pressed down while rotating into the inner diameter of the burnishing jig 106 by lowering the slider portion 113 by 1, as shown in FIG.
The tapered roller 102 receives the rotational force from the taper pin 107 and moves around the inner peripheral surface of the sleeve 2 while rotating in the guide groove 101a. And FIG.
As shown in FIG. 14, the tapered roller 102 rotates while pressing the inner peripheral surface over the entire length of the sleeve 2. Therefore, as shown in FIG.
Is spread over the entire length of the sleeve 2 in the axial direction, and the surface roughness is processed well.

According to the bearing inner diameter machining apparatus, since the taper ratio between the taper pin 107 and the tapered roller 102 of the burnishing jig 106 is 2: 1, the tapered roller 102 extends over the entire length of the sleeve 2. Since the diameter of the circumscribed circle becomes the same, processing over the entire length of the sleeve 2 can be performed. Therefore, the sleeve 2 having a good cylindricity inner diameter as shown in FIG. 15 can be machined.

By restricting the lowering position of the slider portion 113 by the stopper 114, the position where the taper pin 107 enters the burnishing jig 106 is restricted. Therefore, the diameter of the circumscribed circle of the tapered roller 102 is regulated so as to be constant, so that the variation in the inner diameter of the sleeve 2 can be reduced.

According to the bearing inner diameter machining apparatus, in the apparatus for machining the inner diameter of the sleeve 2 of the bearing, a taper pin 107 inserted into the sleeve 2 and a plurality of tapers having a taper capable of rolling around the outer periphery of the taper pin 107 are provided. A roller guide 101 having a roller 102 and a guide groove 101 a rotatably provided on the outer circumference of the tapered pin 107 and accommodating a plurality of tapered rollers 102, and imparting an axial relative movement to the tapered pin 107 with respect to the roller guide 101. And a second motor 112 for rotating the taper pin 107. The taper ratio between the taper pin 107 and the tapered roller 102 is 2: 1. During the plastic working of the inner diameter, the entire length of the tapered roller 102 of the burnishing jig 106 It is possible to change the remains circumscribed circle diameter of the same diameter me.

The tapered roller 102 is inserted over the entire length of the sleeve 2 and rotates the tapered pin 107 and the sleeve 108 relative to each other.
The entire area is simultaneously processed while pressing the inner peripheral surface by receiving the transmission force from the taper pin 107 over the entire length of the sleeve 2, so that the taper pin 10 extends over the entire length of the sleeve 2.
The entire area can be simultaneously machined while pressing the inner peripheral surface by receiving the transmission force from.

A stopper 114 for regulating the relative movement of the taper pin 107 in the axial direction is provided to regulate the processing position of the taper pin 107, and the circumscribed diameter of the tapered roller 102 for determining the finished dimension of the inner diameter of the bearing is kept constant. Therefore, it is possible to reduce variations in the finished inner diameter of the sleeve 2.

Next, burnishing of the outer peripheral surface of the shaft will be described with reference to FIGS. FIG. 16 is a cross-sectional view showing a main part of a shaft outer diameter processing device which is a cylindrical surface processing device, and FIG. 17 is a cross-sectional view taken along line CC in FIG.
As shown in FIGS. 16 and 17, the burnishing jig 316 of the shaft outer diameter processing device includes a cylindrical roller 131 having a tapered surface 137 formed on an inner peripheral surface, and a tapered roller 132.
Roller guide 135 for guiding the roller and roller guide 13
5 is provided with a tapered roller 132 rotatably supported via positioning pins 133a and 133b, and a shank portion.

The cylindrical roller 131 has a tapered surface 137 on the inner peripheral surface thereof, serves as a rolling surface of the tapered roller 132, and moves in and out of the roller guide 135 in the U and D directions in FIG. The circumscribed circle can be adjusted over the entire length of the attached roller 132, and at the same time, the taper ratio is configured so that the circumscribed circle is the same over the entire length of the tapered roller 32. That is, the taper ratio between the tapered surface 137 and the tapered roller 132 is set to 2: 1.

The operation of the shaft outer diameter machining apparatus configured as described above will be described with reference to FIGS. As shown in FIG. 16, the shaft 43 as a workpiece is attached to a predetermined position of the fixture 139. Next, the portion of the tapered roller 132 of the burnishing jig 136 is attached to the outer diameter of the shaft 43. When the cylindrical roller 131 rotates, the tapered roller 132 of the burnishing jig 136 is rotated.
Takes a rotational force from the cylindrical roller 131 and makes a revolution around the outer peripheral surface of the shaft 43 while rotating. Then, the tapered roller 132 rotates while pressing the outer peripheral surface over the entire length of the processing surface of the shaft 43. Therefore, the outer diameter of the shaft 43 is pressed over the entire length of the processed surface of the shaft 43, and the surface roughness is favorably processed.

According to the shaft outer diameter processing apparatus, the taper ratio between the tapered surface 137 of the cylindrical roller 131 and the tapered roller 132 is 2: 1. Since the diameter of the inscribed circle of the tapered roller 132 is the same, it is possible to perform simultaneous processing over the entire length of the shaft 43. Therefore, the shaft 43 having a good cylindricity outer diameter can be machined.

According to the shaft outer diameter processing apparatus, in the apparatus for processing the outer diameter of the shaft 43, there is provided a cylindrical roller 131 mounted on the shaft 43, and a plurality of tapered rollers which can roll on the inner periphery of the cylindrical roller 131. And a roller guide 135 for guiding the tapered roller 132, and the taper ratio between the tapered surface 137 of the cylindrical roller 131 and the tapered roller 132 is 2: 1. During processing, the inscribed circle diameter can be changed while maintaining the same diameter over the entire length of the tapered roller 132 of the burnishing jig 136.

The tapered roller 132 is mounted over the entire length of the shaft 43, and rotates the cylindrical roller 131 and the tapered roller 132 relative to each other.
The transmission force from the cylindrical roller 131 is applied over the entire length of the surface to be processed, and the entire area is simultaneously processed while pressing the outer peripheral surface. Therefore, the transmission from the cylindrical roller 131 over the entire length of the shaft 43 is performed. The entire area can be processed simultaneously while pressing the outer peripheral surface under the force.

The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the gist of the present invention.

[0066]

As is apparent from the above description, according to the present invention, since the grooves are formed by rolling, the generation of cuts is very small and the processing time can be greatly reduced as compared with the cutting processing. In addition, since there is no cutting of the metal fiber in the processed portion, the strength is excellent. Further, since the hard sphere can be immersed, the groove can be formed by one-way processing, and a very high precision groove can be formed without causing a pitch shift of the groove formed on the cylindrical surface or a deformation of the groove. be able to.

Further, according to the method for manufacturing a workpiece having a cylindrical surface or the apparatus for manufacturing the same according to the present invention, the dynamic pressure grooves formed in the inner hole of the bearing sleeve are formed by rolling. Since it is very small, the processing time can be greatly shortened as compared with the cutting processing, and since there is no cutting of the metal fiber in the processed part, the strength is excellent. Furthermore, since the hard spheres can be immersed, the dynamic pressure grooves can be formed by one-way processing, and the pitch of the dynamic pressure grooves formed on the cylindrical surface and the deformation of the dynamic pressure grooves do not occur. An accurate dynamic pressure groove can be formed.

Further, according to the method or the apparatus for manufacturing a dynamic pressure groove of a fluid bearing of the present invention, the dynamic pressure groove formed in the inner hole of the bearing sleeve is formed by rolling, so that the occurrence of cuts is minimal. In addition, the processing time can be significantly reduced as compared with the cutting processing, and the strength is excellent because there is no cutting of the metal fiber in the processed portion. Furthermore, since the hard ball can be immersed, the formation of the dynamic pressure groove can be performed by one-way processing, and the pitch deviation of the dynamic pressure groove formed on the cylindrical surface,
It is possible to form an extremely accurate dynamic pressure groove without causing deformation of the dynamic pressure groove.

[Brief description of the drawings]

FIG. 1 is an axial sectional view for explaining a method and an apparatus for manufacturing a hydrodynamic bearing hydrodynamic groove according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating the entire structure of the hydrodynamic bearing manufactured by the method and the apparatus for manufacturing a hydrodynamic bearing hydrodynamic groove according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a bearing sleeve structure of a fluid bearing to which a method and a device for manufacturing a fluid dynamic pressure groove according to the first embodiment of the present invention are applied.

FIG. 4 is a view showing a groove processing tool for processing the dynamic pressure groove of the bearing sleeve, which is used in the method and the apparatus for manufacturing the hydrodynamic bearing dynamic pressure groove according to the first embodiment of the present invention;
4A is a sectional view, and FIG. 4B is a sectional view taken along line AA in FIG.

FIG. 5 is a view showing a bearing sleeve structure of a herringbone type fluid bearing to which a method and an apparatus for manufacturing a fluid dynamic pressure groove according to a second embodiment of the present invention are applied.

FIG. 6 is a partial cross-sectional view showing a main part structure of a groove processing tool used in a method and an apparatus for manufacturing a hydrodynamic bearing hydrodynamic groove according to a second embodiment of the present invention.

FIG. 7 shows a method of manufacturing a hydrodynamic groove according to a second embodiment of the present invention and a method of removing the groove processing tool from the bearing sleeve when the groove processing tool used in the apparatus finishes processing the dynamic pressure groove. FIG.

FIG. 8 shows a method of manufacturing a hydrodynamic bearing groove according to a modification of the second embodiment of the present invention, and a taper portion is provided in a hard ball holding portion of a shaft member used in the apparatus for fine adjustment of the tangent diameter of the hard ball. FIG.

FIG. 9 is a partial sectional view showing a method and an apparatus for manufacturing a dynamic pressure groove of a fluid bearing according to a third embodiment of the present invention.

FIG. 10 is a partial cross-sectional view illustrating a method of manufacturing a dynamic pressure groove of a fluid bearing according to a third embodiment of the present invention and a jig extraction of the apparatus.

FIG. 11 is a view showing a method of manufacturing a dynamic pressure groove of a fluid bearing according to a third embodiment of the present invention and an entire structure of a fluid bearing manufactured by the apparatus.

FIG. 12 is a cross-sectional view of a bearing inner diameter processing device.

FIG. 13 is a cross-sectional view showing a main part of the bearing inner diameter processing device.

FIG. 14 is a sectional view taken along line BB of FIG.

FIG. 15 is a cross-sectional view of a bearing sleeve processed by the bearing inner diameter processing device.

FIG. 16 is a cross-sectional view showing a main part of the shaft outer diameter processing device.

FIG. 17 is a sectional view taken along line CC in FIG. 16;

[Explanation of symbols]

 1,41 Fluid bearing 2,22,42 Bearing sleeve 2a, 22a Inner hole 3,43 Shaft 4 Lubricant 5,45 Dynamic pressure groove 6 Gap 7 Thrust bearing 8 Auxiliary plate 10,30 Groove processing tool 11,31 Shaft member 11a , 31a Hard sphere pool 12, 32 Hard sphere holder 12a, 32a Holder hole 13, 13a, 13b Hard sphere 15a Sliding window 16 Circumferential caulking 17 Sleeve fixing tool 25, 25a to 25h Dynamic pressure groove 33, 33a to 33h Hard sphere 44 Hard sphere escape groove 50 Shaft processing tool 51 Cylindrical member 52 Hard sphere holder 53 Hard sphere 58 Hard sphere pool

Claims (13)

[Claims] 1. A manufacturing apparatus for a workpiece having a cylindrical surface formed by engraving a groove on a cylindrical surface, comprising: a hard ball holder for rollingly holding a plurality of hard balls for rolling a groove on the cylindrical surface; An apparatus for manufacturing a workpiece having a cylindrical surface, comprising: a rotating member that holds the hard ball so as to be able to protrude and retract from the hard ball holder toward the cylindrical surface. 2. A method for manufacturing a workpiece having a cylindrical surface formed by engraving a groove in a cylindrical surface, wherein a plurality of hard spheres are rollably held by a hard sphere holder, and the hard sphere holder surface is removed from the cylindrical surface. In a state where the hard spheres are protruded toward, a groove is rolled in the cylindrical surface, and after the grooves are formed, the hard spheres are immersed from the surface of the hard sphere holder, and along the axial direction of the cylindrical surface. A method for manufacturing a workpiece having a cylindrical surface, wherein the hard sphere holder and the hard sphere are released from the workpiece. 3. A manufacturing apparatus for manufacturing the dynamic pressure groove of a fluid bearing having a bearing sleeve in which a dynamic pressure groove is formed in an inner hole and a shaft inserted into the inner hole, A sleeve fixing tool for holding a bearing sleeve, and a groove processing tool for holding a plurality of hard balls so that they can roll freely and the tangent diameter of the hard balls is slightly larger than the inner diameter of the groove processing portion of the fluid bearing sleeve. A machining state where the tangent diameter of the hard sphere is slightly larger than the inner diameter of the grooved portion of the fluid bearing sleeve, and a drawing state where the tangent diameter of the hard sphere is slightly smaller than the inner diameter of the grooved portion of the fluid bearing sleeve In the processing state, the groove processing tool is inserted into the inner hole of the bearing sleeve, and the groove processing tool is provided with a rotational motion and an axial feed to the plurality of hard balls. Into the inner hole so that the bearing sleeve The dynamic pressure groove is rolled on the inner peripheral surface of the fluid bearing, and in the withdrawn state, the tangent diameter of the hard sphere is slightly smaller than the inner diameter of the grooved part of the fluid bearing sleeve by the switching means and can be pulled out. Manufacturing equipment for dynamic pressure grooves of fluid bearings. 4. The grooving tool has rolling spheres at opposing positions on a plane orthogonal to the axis of the shaft member, and the grooving tool is attached to a substantially central portion of the bearing sleeve. 4. The hydrodynamic groove manufacturing apparatus for a fluid bearing according to claim 3, wherein the hydrodynamic groove is reversely rotated around the boundary to form a dynamic pressure groove having a shape in which the inclination direction is reversed. 5. The grooving tool is characterized in that a plurality of hard spheres are coaxially and rotatably mounted on opposing positions at equal pitches on the same plane perpendicular to the axial direction of the shaft member. The apparatus for manufacturing a dynamic pressure groove of a fluid bearing according to claim 4. 6. The shaft member of the groove machining tool is configured to hold a plurality of hard spheres such that the tangent diameter of the plurality of hard spheres is slightly larger than the inner diameter of the groove machining portion of the fluid bearing sleeve, and the shaft member is a hard sphere holder. Inside, the hard ball is held in the groove of the shaft member, and it can be switched to a structure in which the tangent diameter of the hard sphere is slightly smaller than the inner diameter of the grooved portion of the fluid bearing sleeve. The manufacturing apparatus of a hydrodynamic groove of a hydrodynamic bearing according to claim 3, wherein: 7. The shaft member of the groove machining tool is configured to hold a plurality of hard spheres such that the tangent diameter of the plurality of hard spheres is slightly larger than the inner diameter of the groove machining portion of the fluid bearing sleeve. 4. A structure in which a tapered portion is provided in the portion so that the tangent diameter of the hard sphere can be finely adjusted.
The manufacturing apparatus of the dynamic pressure groove of the fluid bearing according to the above. 8. The apparatus according to claim 3, wherein at least the hard ball holding portion of the hard ball and groove processing tool is made of a material harder than the fluid bearing sleeve. 9. The hydrodynamic bearing according to claim 3, wherein a depth of the dynamic pressure groove formed by the hard sphere of the groove processing tool is a depth of several micrometers to several tens of micrometers. Manufacturing equipment for dynamic pressure grooves. 10. A manufacturing method for manufacturing said dynamic pressure groove of a fluid bearing having a bearing sleeve in which a dynamic pressure groove is engraved in an inner hole and a shaft inserted into said inner hole. Is fixed by a sleeve fixing tool, and a plurality of hard balls can be rolled freely by a groove processing tool, and held so that the tangent diameter of the hard balls is slightly larger than the inner diameter of the groove processing portion of the fluid bearing sleeve, Inserting the grooving tool into the inner hole of the bearing sleeve, giving the grooving tool rotational movement and axial feed;
The plurality of hard spheres are cut into the inner hole to form a dynamic pressure groove on the inner peripheral surface of the bearing sleeve. After the dynamic pressure groove is formed, the tangent diameter of the hard sphere is changed by the switching means for the fluid bearing. A method of manufacturing a dynamic pressure groove of a fluid bearing, wherein the groove is slightly smaller than an inner diameter of a groove processed portion of the sleeve and then pulled out. 11. A groove processing tool having rollable hard spheres at opposing positions on a plane orthogonal to the axis of the shaft member, the rotational direction of which is reversed around a boundary substantially at the center of the bearing sleeve. The method for manufacturing a dynamic pressure groove of a fluid bearing according to claim 10, wherein the dynamic pressure groove is formed such that the inclined direction is opposite to the direction. 12. In a case where the dynamic pressure groove of the bearing sleeve is of a herringbone type comprising a plurality of groove groups having a constant inclination angle, the plurality of groove processing tools correspond to each groove of the groove group. The hard spheres are rotated at the same pitch at opposing positions at the same pitch and coaxially and rotatably mounted on the same plane orthogonal to the axial direction of the shaft member. 11. The method according to claim 10, wherein the rotational direction is reversed around a substantially central portion of the bearing sleeve. 13. The hard ball of the groove processing tool is characterized in that a dynamic pressure groove having a depth of several micrometers to several tens of micrometers is formed on the inner peripheral surface of the fluid bearing sleeve by rolling. A method for manufacturing a hydrodynamic groove for a hydrodynamic bearing according to claim 10.