JPH11132236A - Manufacture of bearing device, bearing device and motor using the bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device, high in mechanical accuracy, and advantageous in reliability, in the bearing device for a motor used to information and image.acoustic apparatuses, etc. SOLUTION: In a bearing device wherein an inner diameter part 2 sliding with a motor shaft, and a flange 3 are integrally formed by sintered alloy; the flange 3 can be worked in a plastic deformation region, by providing an uneven part on the flange 3 at the time of molding the pressed power of sintered alloy, pressing the flange 3 by a plane-like die concurrently with the fabrication of the inner diameter part 2 at the time of re-pressing work, and plastically deforming the projection to fabricate it into a nearly plane state. Consequently, accuracy can be stabilized, mechanical accuracy can be increased, and moreover the plastically deformed portion can be into a condition having extremely few vacancies; thereby providing a bearing device being suppressible in the swell and infiltration of lubricating oil, and excellent in reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to information equipment,
The present invention relates to a method for manufacturing a bearing device used for audio equipment and the like.

[0002]

2. Description of the Related Art In recent years, information equipment and video / audio equipment
As represented by VD (Digital Video Disc),
With the progress of high-density recording of devices, higher mechanical accuracy is also required for bearing devices used in these devices.

A conventional bearing device is disclosed in Japanese Utility Model Laid-Open No. 7-11.
A bearing device for a motor described in Japanese Patent Publication No. 883 is known. FIG. 6 shows the structure of a conventional motor. In FIG. 6, the bearing is a screw 7 together with the stator core 6 on the motor substrate 5.
Is fixed.

[0004]

However, the above configuration has a problem that it is particularly difficult to secure the perpendicularity of the shaft to the motor mounting surface (hereinafter simply referred to as the shaft perpendicularity). The causes of the deterioration of the shaft drop are mainly the flatness of the motor substrate 5 and the accuracy of the single bearing 1. Particularly, when a sintered oil-impregnated bearing is used for the bearing 1, the sintered oil-impregnated bearing is made of iron, copper, etc. After compacting the metal powder in a mold, baking in a high-temperature furnace, and then performing re-pressing, the accuracy is inevitably stabilized due to variations in the density of the metal powder, distortion during firing, etc. And it is difficult to ensure accuracy.

[0005] The sintered oil-impregnated bearing is used in combination with a material (for example, plastic) having a swelling property with respect to the lubricating oil impregnated in the bearing or a material (for example, a sintered part) which penetrates the lubricating oil. In such a case, there have been problems such as surrounding parts being violated by the lubricating oil, and the amount of the lubricating oil in the bearing being reduced, thereby deteriorating reliability.

An object of the present invention is to solve such conventional problems and to provide a highly reliable bearing device with high mechanical accuracy.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an inner diameter portion which slides on a shaft and a flat surface portion used as a support surface for a mating surface with other parts or a jig in assembling during assembly. In the method of manufacturing a bearing device in which the inner diameter portion and the flat portion are integrally formed of a sintered alloy, an uneven portion is provided on the flat portion at the time of compacting the sintered alloy, Simultaneously with the forming process of the inner diameter portion, the flat portion is pressed by a flat mold, and the convex portion is plastically deformed, thereby forming a substantially flat shape.

Thus, the flat portion is processed in the plastic deformation region, so that the accuracy is stabilized and the mechanical accuracy can be increased. Further, since the plastically deformed portion has very few holes, swelling and permeation of the lubricating oil impregnated in the bearing into the surrounding parts is suppressed, which is advantageous in terms of bearing reliability and the like. A simple bearing device can be provided.

Alternatively, an inner diameter portion that slides on the shaft,
In a method of manufacturing a bearing device, having a mating surface with another component or a flat portion used as a support surface with a jig during assembly, the inner diameter portion and the flat portion are integrally formed of a sintered alloy. By providing the uneven portion on the flat portion, swelling and penetration of the lubricating oil impregnated in the bearing into the surrounding components can be suppressed, and a highly reliable bearing device can be provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a flat surface used as a support surface in a jig for mating a surface of a motor shaft with another component or assembling a jig during assembly. In the method of manufacturing a bearing device, wherein the inner diameter portion and the flat portion are integrally formed of a sintered alloy, the unevenness portion is provided on the flat portion at the time of compacting the sintered alloy, Simultaneously with the forming of the inner diameter portion, the flat portion is pressed by a flat mold, and the convex portion is plastically deformed, so that the flat portion is plastically deformed. Since it is machined in the region, the accuracy is stable and the mechanical accuracy is high, and furthermore, the plastically deformed portion has very few holes, so the parts around the lubricating oil impregnated in the bearing Swelling and penetration into
It is possible to provide a bearing device that is advantageous in terms of bearing reliability and the like.

According to a second aspect of the present invention, in the method according to the first aspect of the present invention, the uneven portion is formed by knurling the surface of a powder metal mold to form a plurality of uneven portions on the bearing body. An example is shown.

According to a third aspect of the present invention, the concavities and convexities are formed in the bearing body by providing a plurality of grooves formed by concentrically engraving the surface of a dust mold. Another embodiment of the method of claim 1 is shown.

According to a fourth aspect of the present invention, there is provided an inner diameter portion which slides on a shaft of a motor, and a flat surface portion which is used as a support surface with a jig for mating with other parts or assembling with other parts.
In the method for manufacturing a bearing device in which the inner diameter portion and the flat portion are integrally formed of a sintered alloy, the flat portion is provided with an uneven portion by a powder metal mold, and lubricating oil impregnated in the bearing is provided. Swelling and permeation to surrounding components are suppressed, and a method of manufacturing a bearing device with high reliability of a bearing can be provided.

According to a fifth aspect of the present invention, the uneven portion is obtained by forming a plurality of uneven portions on the bearing body by knurling the surface of a dust mold. An example is shown.

According to a sixth aspect of the present invention, the concavities and convexities are formed in the bearing body by providing a plurality of grooves formed by concentrically engraving the surface of a dust mold. Another embodiment of the method of claim 4 is shown.

[0016] The invention according to claim 7 is the invention according to claims 1 to 6.
With the bearing device according to any one of the methods for manufacturing a bearing device, accuracy and reliability of the bearing device can be improved.

According to an eighth aspect of the present invention, there is provided a motor provided with the bearing device according to the seventh aspect, and it is possible to improve the accuracy (particularly, the axial suspension) and reliability of the motor.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) FIG. 1A shows a bearing 1 which has been subjected to a compacting process and then a sintering process.

In FIG. 1 (a), a bearing 1 is integrally formed with an inner diameter portion 2 which slides on a motor shaft and a flange 3 which is a mating surface with a motor substrate when assembling the motor. A plurality of protrusions 4
Are formed, and the whole is formed by compacting metal powders such as iron and copper with a mold. Here, the projections 4 are formed by transferring the shape to the bearing body by subjecting the surface of a mold for compacting the bearing 1 to a so-called knurling process in which sharp edges are cut vertically and horizontally.

FIG. 1B shows a bearing 1 after re-pressing.
Is shown. In FIG. 1B, the inner diameter portion 2 of the bearing 1
Is press-fitted with a shaft slightly larger than the inner diameter of the fired inner diameter portion 2 so that the inner diameter is plastically deformed and processed to a slightly larger inner diameter. At the same time, the flange 3 is pressed by a flat mold to form the projection 4. It is plastically deformed and processed into a substantially planar shape. Thereby, the verticality of the flange 3 with respect to the inner diameter part 2 is ensured.

The bearing 1 after re-pressing is impregnated with lubricating oil by vacuum impregnation or the like, and when assembled into a motor, the lubricating oil is supplied between the rotating shaft and the lubricating oil to provide good lubrication. The state is secured.

Hereinafter, the reason why the mechanical accuracy of the bearing device is increased will be described with reference to the drawings.

FIG. 2A is a view schematically showing a cross section of the flange 3 which has been subjected to a powder compacting and then subjected to a sintering process, and FIG. 2B is a view schematically showing a cross section of the flange 3 which has been repressed.

In FIG. 2 (a), a plurality of irregularities are formed on the surface of the flange 3 by knurling the surface of a compacting die to transfer the shape to the surface of the flange 3. The figure shows a state in which the flange 3 is slightly inclined with respect to the inner diameter portion 2 due to variations in material density, distortion during firing, and the like.

In FIG. 2 (b), the surface of the flange 3 is crushed in the uneven portion, and the crushed surface is processed almost flat. When pressing with a flat mold, the convex portion is pressed in a state close to point contact, so that extremely high stress is generated near the contact surface and plastic deformation occurs. In addition, the portion where the convex portion is plastically deformed has a higher density than other portions, and at the same time, is deformed so as to escape to the concave portion side. At this time, since the stress on the surface of the flange 3 often exceeds the yield stress of the material,
It can be formed into a shape closer to the mold shape with less springback. Therefore, as long as the accuracy of the re-pressing mold is ensured, the inclination of the powder 3 and the flange 3 with respect to the inner diameter portion 2 at the time of firing can be corrected, and high mechanical accuracy can be obtained.

Further, the portion where the convex portion is plastically deformed is
The density of the material is increased, and the state of the holes is very small. Therefore, when the bearing 1 is used in combination with a material (for example, plastic) having a swelling property with respect to the lubricating oil or a material (for example, a sintered component) which penetrates the lubricating oil, the swelling and the permeation of the lubricating oil are prevented. It is suppressed, which is advantageous in terms of reliability and the like.

For the above reasons, according to the present invention, it is possible to provide a bearing device having high mechanical accuracy and advantageous in reliability and the like.

In the above description, a plurality of concaves and convexes are provided on the plane portion by knurling the surface of the mold. However, as shown in FIG. Further, the present invention can be similarly applied to a case where the concentric projections and depressions 41 are formed.

FIG. 3A shows the flange portion which has been subjected to the compacting and sintering process, and FIG. 3B shows the flange portion after the unevenness portion has been repressed.

(Embodiment 2) FIG. 4 shows a bearing 1 of this embodiment.

In FIG. 4, the bearing 1 is integrally formed with an inner diameter portion 2 which slides on the shaft of the motor and a flange 3 which is a mating surface with a motor substrate 5 when assembling the motor. In this portion, a plurality of concentric projections 4 are formed by forming concentric projections and depressions on the surface of a mold for compacting the bearing 1 to transfer this shape to the bearing 1 body.

FIG. 5 shows a state in which the bearing 1 is assembled in a motor. In FIG. 5, the bearing 1 is caulked and fixed to a motor board 5 in which a resin circuit board is integrally fixed to an iron plate. The flange 3 of the bearing is configured to be in direct contact with the motor substrate 5. At this time, since the flange 3 has irregularities, the contact area is smaller than when the flange 3 is flat. Has become. For this reason, the lubricating oil suppresses the motor substrate 5 from swelling and the motor substrate 5 from being deformed, and the amount of lubricating oil in the bearing 1 from being reduced, which is advantageous in terms of bearing reliability and the like.

In the above embodiment, concentric concavities and convexities are formed on the flange surface. However, the same effect can be obtained by using a knurled shape.

[0035]

As is clear from the description of the above embodiment,
According to the first to third aspects of the present invention, the flat portion is processed in the plastic deformation region at the time of repressing, so that it is possible to provide a method of manufacturing a bearing device with stable accuracy and high mechanical accuracy. . Further, since the plastically deformed portion has a high material density and a very small number of pores, swelling and penetration of lubricating oil are suppressed, and a method of manufacturing a bearing device which is advantageous in terms of bearing reliability and the like. Can be provided.

Further, according to the present invention, since the contact area is reduced, the swelling and permeation of the lubricating oil is suppressed, and the production of a bearing device which is advantageous in terms of the reliability of the bearing and the like. A method can be provided.

Further, it goes without saying that in the bearing device according to the manufacturing method of the first to sixth aspects and the motor incorporating the bearing device, accuracy and reliability are improved.

[Brief description of the drawings]

FIG. 1A is a half sectional perspective view showing a bearing device according to a first embodiment of the present invention. FIG. 1B is a half sectional perspective view showing a bearing device after compaction according to the first embodiment of the present invention.

2A is a cross-sectional view of a bearing flange surface according to a first embodiment of the present invention. FIG. 2B is a cross-sectional view of the bearing flange surface after repressing according to the first embodiment of the present invention.

FIG. 3 (a) is a half sectional perspective view showing a bearing device according to a first embodiment of the present invention, and (b) is a half sectional perspective view showing a bearing device after repressing according to the first embodiment of the present invention.

FIG. 4 is a half sectional perspective view showing a bearing device according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a motor according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a conventional motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bearing 2 Inner diameter part 3 Flange 4,41 Projection 5 Motor board 6 Stator core 7 Screw

Claims (8)

[Claims] 1. Manufacture of a bearing device having an inner diameter portion which slides on a shaft, and a flat portion substantially perpendicular to the inner diameter portion, wherein the inner diameter portion and the flat portion are integrally formed of a sintered alloy. In the method, an uneven portion is provided on the flat portion at the time of compacting the sintered alloy, and the flat portion is pressed by a flat mold at the same time as the forming process of the inner diameter portion at the time of repressing, and the convex portion is formed. A method of manufacturing a bearing device which is formed into a substantially planar shape by plastically deforming a portion. 2. The method for manufacturing a bearing device according to claim 1, wherein the concave and convex portions are formed with a plurality of concave and convex portions on the bearing body by knurling the surface of a powder metal mold. 3. The method for manufacturing a bearing device according to claim 1, wherein the concavities and convexities are formed in the bearing body by providing a plurality of grooves concentrically cut on the surface of the powder mold. . 4. Manufacture of a bearing device having an inner diameter portion that slides on a shaft, and a flat portion substantially perpendicular to the inner diameter portion, wherein the inner diameter portion and the flat portion are integrally formed of a sintered alloy. The method of manufacturing a bearing device, wherein the unevenness portion is provided on the flat surface portion by a dust mold. 5. The method for manufacturing a bearing device according to claim 4, wherein the concave and convex portions are formed with a plurality of concave and convex portions on the bearing main body by knurling the surface of a powder metal mold. 6. The method for manufacturing a bearing device according to claim 4, wherein the concavities and convexities are formed in the bearing body by providing a plurality of grooves concentrically cut on the surface of the powder mold. . 7. A bearing device according to the method for manufacturing a bearing device according to claim 1. 8. A motor comprising the bearing device according to claim 7.