JP3727239B2 - Manufacturing method of radial bearing parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a radial bearing part of a fluid dynamic bearing device, and particularly has a feature in a processing method for widening an effective area for a thrust bearing part.
[0002]
[Prior art]
In the conventional hydrodynamic bearing device, as shown in FIG. 4 (a), a sleeve 1 as a radial bearing part is formed in a cylindrical shape, and has a large-diameter portion 3 for attaching a disc-shaped thrust bearing part 2, and a radial part. A small-diameter portion 4 serving as a bearing is provided, and a herringbone-like dynamic pressure generating groove 5 is provided in the small-diameter portion 4.
[0003]
When the sleeve 1 is manufactured, processing methods such as rolling, cutting, and etching are used. In the technique disclosed in Japanese Patent Application Laid-Open No. 7-164086, as shown in FIG. In order to remove bulges generated by rolling or the like forming the grooves 3 and burrs generated by other processes, and to make the inner diameter of the small diameter part 4 uniform, a hard sphere 6 is inserted into the small diameter part 4 through the large diameter part 3. Finishing processing is performed.
[0004]
[Problems to be solved by the invention]
However, in the conventional manufacturing method described above, when the rigid sphere 6 is passed, the inner peripheral edge portion 7a surrounding the communication opening 7 between the large diameter portion 3 and the small diameter portion 4 rises due to plastic deformation, and as shown in FIG. A raised portion 8 of μm remains. Then, there is a problem that the raised portion 8 comes into contact with the thrust bearing component 2 during the rotation of the sleeve 1 (and hence the thrust bearing component 2) or the shaft and causes damage.
[0005]
For this reason, a large chamfering process is applied to the inner peripheral edge portion in advance to form a relief portion, so that the thrust bearing component 2 is not contacted even if a bulge occurs. However, if the relief portion is enlarged, the effective area facing the thrust bearing component 2 is reduced, and the dynamic pressure generated between the thrust bearing component 2 is reduced, so that the relative floating amount of the rotating sleeve 1 or shaft is reduced. However, there was a problem that the start of ascent was delayed.
[0006]
The present invention solves the above problems, and an object of the present invention is to provide a method for manufacturing a radial bearing component that does not damage the thrust bearing component even if deformation occurs during processing, and that provides good flying characteristics. It is.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is to chamfer the inner peripheral edge where the bulge is generated by a hard sphere in advance, and then form a stepped portion or a tapered surface, and then pass the hard sphere. Then, these processed parts are pushed up by plastic deformation (raising) by a hard sphere, and the surface is just flat after plastic deformation. This eliminates the protrusions that have remained on the inner peripheral edge in the past, prevents damage to the thrust bearing component, and allows a wider effective area facing the thrust bearing component. A large dynamic pressure can be generated.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, a small-diameter portion for supporting the shaft in the radial direction and a large-diameter portion to which a disc-shaped thrust bearing component is attached are formed, and a dynamic pressure generating groove is formed on the inner peripheral surface of the small-diameter portion. And a method of manufacturing a cylindrical radial bearing part in which a steel ball that causes plastic deformation to remove the burrs and bulges of the small diameter portion in which the dynamic pressure generating groove is formed and uniformize the inner diameter is passed through the small diameter portion through the large diameter portion And chamfering the inner peripheral edge surrounding these communication openings and forming a stepped portion following the chamfered portion on the inner surface facing the thrust bearing component at the time of cutting to form the small diameter portion and the large diameter portion. The inner surface including the stepped portion facing the thrust bearing portion is flattened by plastic deformation when the steel ball is passed, and is prevented from projecting to the thrust bearing portion side .
[0009]
According to the second aspect of the present invention, a small-diameter portion that supports the shaft in the radial direction and a large-diameter portion to which a disc-shaped thrust bearing component is attached are formed, and a dynamic pressure generating groove is formed on the inner peripheral surface of the small-diameter portion. And a method of manufacturing a cylindrical radial bearing part in which a steel ball that causes plastic deformation to remove the burrs and bulges of the small diameter portion in which the dynamic pressure generating groove is formed and uniformize the inner diameter is passed through the small diameter portion through the large diameter portion And chamfering the inner peripheral edge surrounding these communication openings during the cutting process for forming the small diameter part and the large diameter part, and a gentle upward slope following the chamfered part on the inner surface facing the thrust bearing component the previously formed a tapered surface forming the steel ball is planarized an inner surface including the tapered surface facing the thrust bearing portion by plastic deformation when passing, preventing the protruding thrust bearing portion And wherein the door.
[0010]
According to a third aspect of the present invention, a small-diameter portion for supporting the shaft in the radial direction and a large-diameter portion to which a disc-shaped thrust bearing component is attached are formed, and a dynamic pressure generating groove is formed on the inner peripheral surface of the small-diameter portion. And a method of manufacturing a cylindrical radial bearing part in which a steel ball that causes plastic deformation to remove the burrs and bulges of the small diameter portion in which the dynamic pressure generating groove is formed and uniformize the inner diameter is passed through the small diameter portion through the large diameter portion And chamfering the inner peripheral edge surrounding these communication openings at the time of cutting to form the small diameter portion and the large diameter portion, and a step portion following the chamfered portion on the inner surface facing the thrust bearing component, A taper surface having a gentle upward slope following the step portion is formed, and the inner surface including the step portion and the taper surface facing the thrust bearing portion is flattened by plastic deformation when the steel ball is passed. , Su Characterized in that to prevent the protruding strike the bearing portion side.
[0011]
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
(Embodiment 1)
FIG. 1 is an enlarged view of a main part for explaining a method for manufacturing a radial bearing component in the first embodiment. Since the schematic overall configuration of this radial bearing part is the same as that of the conventional one described with reference to FIG. 4, FIG. 4 is used, and in FIG. 1, parts having the same functions as those of the conventional radial bearing part are shown in FIG. The same symbol is attached. The method for manufacturing the radial bearing part corresponds to claim 1.
[0012]
A cylindrical sleeve 1 serving as a radial bearing device is formed with a large-diameter portion 3 for mounting a disc-shaped thrust bearing component 2 and a small-diameter portion 4 serving as a radial bearing. The small-diameter portion 4 has a herringbone shape. A dynamic pressure generating groove 5 is formed. An inner surface facing the thrust bearing component 2 on the outer peripheral side of the communication opening 7 between the large diameter portion 3 and the small diameter portion 4 is formed as a flat portion 9 parallel to the surface of the thrust bearing component 2.
[0013]
When manufacturing such a sleeve 1, the large diameter portion 3 and the small diameter portion 4 are formed by a processing method such as rolling, cutting, etching, and the like, and the dynamic pressure generating groove 5 is formed by rolling processing.
[0014]
At that time, in the cutting process after the rolling process of the dynamic pressure generating groove 5, chamfering is performed on the inner peripheral edge surrounding the communication opening 7 between the large diameter part 3 and the small diameter part 4, and the thrust bearing component 2 is provided. A stepped portion 11 following the chamfered portion 10 is formed on the opposing inner surface. The step portion 11 is assumed to have a step between the flat surface 11 a in the direction along the surface of the thrust bearing component 2 and the surface of the flat portion 9.
[0015]
After that, in order to remove the raised portions and burrs generated in the small diameter portion 4 during the rolling process of the dynamic pressure generating groove 5 and to make the inner diameter of the small diameter portion 4 uniform, Through the small diameter portion 4.
[0016]
By doing in this way, the plastic deformation part 12 by the hard sphere 6 pushes the step part 11 and the chamfering part 10 and flattens them.
The chamfered portion 10 is set to C0.1, and the step portion 11 is approximately 0.2 to 0.3 mm wide and 10 to 20 μm deep. The raised portion was not recognized, and the inner surface facing the thrust bearing part 2 could be flattened.
[0017]
Therefore, compared with the conventional case where only a large chamfered portion is formed as the relief portion, the processing area may be reduced, and the effective area facing the thrust bearing component 2 can be increased, and the thrust bearing component 2 can generate a large dynamic pressure.
(Embodiment 2)
FIG. 2 is an enlarged view of a main part for explaining a method for manufacturing a radial bearing component in the second embodiment. The method for manufacturing the radial bearing part corresponds to claim 2.
[0018]
The method of the second embodiment is different from the method of the first embodiment in that, in the cutting process, chamfering is performed on the inner peripheral edge portion surrounding the communication opening 7 between the large diameter portion 3 and the small diameter portion 4, and A taper surface 13 that forms a gentle upward gradient from the chamfered portion 10 toward the flat portion 9 is formed on the inner surface facing the thrust bearing component 2.
[0019]
When the chamfered portion 10 is set to C0.1 and the tapered surface 13 is inclined at about 1 to 2 degrees with respect to the surface of the flat portion 9, the inner peripheral edge after passing through the hard sphere 6 has a conventional bulge. The portion was not recognized, and the inner surface facing the thrust bearing component 2 could be flattened.
(Embodiment 3)
FIG. 3 is an enlarged view of a main part for explaining a method for manufacturing a radial bearing component in the third embodiment. The method for manufacturing the radial bearing part corresponds to claim 3.
[0020]
The method of the second embodiment is different from the method of the first embodiment in that, in the cutting process, chamfering is performed on the inner peripheral edge portion surrounding the communication opening 7 between the large diameter portion 3 and the small diameter portion 4, and The step 11 is formed on the inner surface facing the thrust bearing component 2, and a stepped portion 11 following the chamfered portion 10 and a tapered surface 13 that forms a gentle upward slope from the stepped portion 11 toward the flat portion 9.
[0021]
The chamfered portion 10 is C0.1, the step portion 11 is approximately 0.2 to 0.3 mm wide, the depth is 10 to 20 μm, and the tapered surface 13 is inclined about 1 to 2 degrees with respect to the surface of the flat portion 9. As a result, the raised portion as in the prior art was not recognized in the inner peripheral edge after passing through the hard sphere 6, and the inner surface facing the thrust bearing component 2 could be flattened.
[0022]
As described above, the inner surface facing the thrust bearing component 2 is flattened by the plastic deformation portion 12 generated when the hard sphere 6 is passed. The thrust bearing part 2 can be prevented from being damaged by contact with the thrust bearing part 2 and the effective area of the inner surface facing the thrust bearing part 2 can be widened. A large dynamic pressure is generated between the thrust bearing part 2 and the floating characteristics. It becomes possible to improve.
[0023]
In addition, what is necessary is just to set the above-mentioned various dimensions suitably according to the rolling white which is the difference of the internal diameter of the small diameter part 4, and the diameter of the steel ball 6. FIG.
[0024]
【The invention's effect】
As described above, according to the present invention, by adopting a component shape that takes into account the bulge during finishing processing through which a hard sphere is passed, the bulge portion that has conventionally occurred on the inner surface facing the thrust bearing component can be eliminated. The problem of damage to the thrust bearing component due to the contact of the raised portion can be solved, the effective area of the inner surface facing the thrust bearing component can be maximized, and the flying characteristics can be improved.
[Brief description of the drawings]
FIG. 1 is an enlarged view of a main part for explaining a method for manufacturing a radial bearing part in Embodiment 1 of the present invention. FIG. 2 is an enlarged view of a main part for explaining a method for manufacturing a radial bearing part in Embodiment 2 of the invention. FIG. 3 is an enlarged view of a main part for explaining a method for manufacturing a radial bearing component according to Embodiment 3 of the present invention. FIG. 4 is a schematic diagram showing a radial bearing component and a thrust bearing component of a hydrodynamic bearing device conventionally used. Overall configuration diagram [FIG. 5] Partially enlarged view showing a raised portion of a radial bearing part manufactured by a conventional method [Explanation of symbols]
1 Sleeve (radial bearing parts)
2 Thrust bearing parts 3 Large diameter part 4 Small diameter part 5 Dynamic pressure generating groove 6 Hard ball 7 Communication opening 8 Flat part
10 Chamfered part
11 steps
12 Plastic deformation part
13 Tapered surface

Claims (3)

A small-diameter portion that supports the shaft in the radial direction and a large-diameter portion to which a disc-shaped thrust bearing component is attached are formed. A dynamic pressure generating groove is formed on the inner peripheral surface of the small diameter portion, and the dynamic pressure generating groove is formed. In the method of manufacturing a cylindrical radial bearing part in which a steel ball that causes plastic deformation to remove the burrs and bulges of the small diameter portion and make the inner diameter uniform is passed through the large diameter portion into the small diameter portion.
During cutting processing for forming the small diameter portion and the large diameter portion, with the inner peripheral edge portion chamfered surrounding these communication opening, to form the stepped portion following the opposing inner surfaces to the thrust bearing parts on the chamfered portion In addition, the inner surface including the step portion facing the thrust bearing portion is flattened by plastic deformation when the steel ball is passed, and the radial bearing component is prevented from protruding toward the thrust bearing portion side . Production method. A small-diameter portion that supports the shaft in the radial direction and a large-diameter portion to which a disc-shaped thrust bearing component is attached are formed. A dynamic pressure generating groove is formed on the inner peripheral surface of the small diameter portion, and the dynamic pressure generating groove is formed. In the method of manufacturing a cylindrical radial bearing part in which a steel ball that causes plastic deformation to remove the burrs and bulges of the small diameter portion and make the inner diameter uniform is passed through the large diameter portion into the small diameter portion.
At the time of cutting to form the small-diameter portion and the large-diameter portion, the inner peripheral edge surrounding these communication openings is chamfered, and the inner surface facing the thrust bearing part has a gentle upward slope following the chamfered portion. A taper surface is formed in advance, and the inner surface including the taper surface facing the thrust bearing portion is flattened by plastic deformation when the steel ball is passed through, thereby preventing protrusion to the thrust bearing portion side. A manufacturing method of radial bearing parts. A small-diameter portion that supports the shaft in the radial direction and a large-diameter portion to which a disc-shaped thrust bearing component is attached are formed. A dynamic pressure generating groove is formed on the inner peripheral surface of the small diameter portion, and the dynamic pressure generating groove is formed. In the method of manufacturing a cylindrical radial bearing part in which a steel ball that causes plastic deformation to remove the burrs and bulges of the small diameter portion and make the inner diameter uniform is passed through the large diameter portion into the small diameter portion.
At the time of cutting to form the small-diameter portion and the large-diameter portion, the inner peripheral edge portion surrounding these communication openings is chamfered, and a step portion following the chamfered portion on the inner surface facing the thrust bearing component and the step portion And a taper surface that forms a gentle upward slope following the step, and by flattening the inner surface including the stepped portion and the tapered surface facing the thrust bearing portion by plastic deformation when the steel ball is passed, A method for manufacturing a radial bearing component, characterized by preventing protrusion to the bearing portion side .

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