TW201335498A - Manufacturing method of bearing assembly - Google Patents

Abstract

A manufacturing method of a bearing assembly includes nest steps: providing a mold; injecting mixture of metal powder and bond into the mold to form an embryo of a bearing body and an embryo of a bearing cover; removing the bond in the embryos of the bearing body and the bearing cover; sintering the embryos of the bearing body and the bearing cover to form a finished bearing body and a finished bearing cover; assembling the finished bearing body and the finished bearing cover to form the bearing assembly.

Description

Bearing device manufacturing method

The present invention relates to a method of manufacturing a bearing device.

At present, bearings are widely used in a variety of equipment, especially dynamic pressure bearings are more commonly used in electronic devices, such as hard disk drives (HDD), compact disc drives (CD-ROM), digital video disc players (DVD), micro-discs In the fields of MiniDisc, magneto-optical disc (MO) and cooling fan, the bearing size of the motor is small, and the requirements for the rotation accuracy and life of the bearing are high.

The dynamic pressure bearing forms a fluid (may be gas or liquid) lubricating oil film in a small gap between the rotating shaft and the bearing, and the lubricating oil generates a dynamic pressure effect by the shearing force flowing through different sectional areas, so that the dynamic pressure bearing The shaft is supported and lubricated with high rigidity, so that the shaft and the bearing are not in direct contact, which can reduce wear and reduce noise. In the dynamic pressure bearing, the formation of the oil film is geometric wedge effect, extrusion effect, surface expansion effect, density wedge effect, viscosity wedge effect and expansion effect.

However, how to keep oil and oil is still a problem faced by dynamic pressure bearings. The lubricating oil between the rotating shaft and the bearing tends to leak along the axial direction toward the end of the bearing and escape into the atmosphere under the various effects caused by the dynamic pressure effect (such as capillary action, pump action), thereby causing the dynamic pressure bearing to be lubricated. The oil is insufficient to work properly, and finally the dynamic bearing fails. At the same time, when the shaft is assembled, when the shaft is squeezed into the inner bore of the dynamic pressure bearing, a large reaction force is generated when the air in the inner hole is compressed. It makes it difficult to fill and assemble the shaft. The industry usually solves the problem of storage and leakage of lubricating oil by opening an oil reservoir on the inner circumferential surface of the dynamic pressure bearing. However, due to the miniaturization of the bearing, the inner diameter of the bearing is relatively reduced, and the hollow portion of the bearing is relatively narrow, so that it is formed. This oil storage tank is extremely difficult, and it is difficult to improve the mass productivity and stability of the product.

In view of the above, it is necessary to provide a method of manufacturing a bearing device which can have a better oil retention effect.

A manufacturing method of a bearing device, comprising the steps of: providing a bearing mold; injecting a mixture of metal powder and a molten binder into the bearing mold by injection molding to form an embryo body of the bearing body and an embryo body of the upper cover, respectively Removing the body of the bearing body and the binder in the body of the upper cover; sintering the body of the bearing body and the body of the upper cover to obtain a bearing body and an upper cover; assembling the upper cover on the bearing body to form the bearing device .

Compared with the prior art, the bearing device is formed by metal powder injection molding, has high shape freedom, can obtain parts close to the final shape to the maximum, and effectively reduces the subsequent processing amount, and is more advantageous than other molding methods. For the manufacture of high melting point, high strength, complex shape parts, easy to achieve automation, mass production.

As shown in FIG. 1 and FIG. 2, the bearing device 100 includes a bearing body 10 and an upper cover 20 disposed on the bearing body 10.

The bearing body 10 has a cylindrical shape, and a shaft hole 17 is formed therein through which the top surface thereof penetrates to the bottom surface. The top surface of the bearing body 10 is recessed inwardly to form a recess 11. The groove 11 includes a plane 110 and a slope 112 formed by extending upward from a circumference of the plane 110. The plane 110 is circular. The slope 112 is annular and extends obliquely upward from the outer edge of the plane 110. The bottom end of the bearing body 10 is provided with a ring groove 12 surrounding the bottom end of the bearing body 10. The bearing body 10 forms a guiding surface 13 at the top end of the ring groove 12. The guiding surface 13 extends from the top to the bottom in a tapered shape. Referring to FIG. 3 , the opposite sides of the bottom surface of the bearing body 10 respectively extend downward to form a blocking wall 14 , and an opening 15 is respectively formed between the edge ends of the two blocking walls 14 . The side surface of the bearing body 10 is recessed inwardly on opposite sides of the position near the bottom end thereof to form an oil guiding groove 16. Each oil guiding groove 16 is correspondingly disposed above the opening 15 and extends downward from a central portion of the bearing body 10 to a bottom end of the bearing body 10 and communicates with the opening 15 respectively. The bearing body 10 defines a through hole 18 communicating with the shaft hole 17 in the oil guiding groove 16 on the right side. The through hole 18 is circular and is disposed at the top end of the oil guiding groove 16 on the right side.

The upper cover 20 includes a top wall 21 and a cylindrical side wall 23 extending downward from the periphery of the top wall 21. The top wall 21 has a circular plate shape, and a through hole 210 is formed in a middle portion thereof. The side wall 23 is formed by vertically extending downward from the periphery of the top wall 21, and an end surface thereof is formed with an assembly surface 230 corresponding to the slope 112 of the bearing body 10. The outer edge of the assembly surface 230 extends outwardly from the side wall 23 in a tapered shape.

Referring to FIG. 4 and FIG. 5 , in particular, the bearing device 100 is disposed in a sleeve 30 , and a rotating shaft 40 is disposed in the shaft hole 17 of the bearing device 100 and extends through the through hole 210 of the upper cover 20 . Up to the outside of the upper cover 20. The sleeve 30 includes a bottom plate 32 and a cylindrical sleeve 34 extending upward from the periphery of the bottom plate 32. The bottom end of the bearing body 10 abuts against the bottom plate 32, and defines a first oil storage space 50 between the inner side of the two retaining walls 14 and the bottom surface of the bearing body 10, and the two oil retaining walls 14 The outer side of the annular groove 12 and the sleeve 34 are enclosed by a second oil storage space 60. The first oil storage space 50, the second oil storage space 60, and the bearing body 10 and the rotating shaft 40 are filled with a lubricating fluid. The upper cover 20 is disposed at a top end of the sleeve 34. In use, the rotating shaft 40 rotates and squeezes the lubricating fluid, thereby establishing a dynamic pressure between the bearing body 10 and the rotating shaft 40 to prevent direct contact therebetween. During the rotation of the rotating shaft 40, the lubricating fluid in the first oil storage space 50 rises into the gap between the rotating shaft 40 and the bearing body 10, and the lubricating flow of the portion between the rotating shaft 40 and the bearing body 10 The flow through the through hole 18 and through the guiding of the oil guiding groove 16 flows into the second oil storage space 60, and then flows back into the first oil storage space 50 through the opening 15, thereby achieving the establishment between the rotating shaft 40 and the bearing body 10. The purpose of the pressure and the effect of the return flow of the lubricating fluid prevent the lubricating fluid from splashing out from the top end of the bearing device 100. The guiding surface 13 of the bottom end of the bearing body 10 is disposed at the top end of the second oil storage space 60, so that the lubricating fluid in the second oil storage space 60 can be prevented from overflowing into the gap between the bearing body 10 and the sleeve 34, and The guiding surface 13 has a tapered design from the top to the bottom, and can guide the lubricating fluid flowing to the top of the second oil storage space 60 to flow downward, thereby accelerating the first oil storage space 50 and the second oil storage space 60. Lubrication of the fluid. The upper cover 20 can prevent the lubricating fluid rising to the tip end of the bearing body 10 from splashing to the outside of the bearing device 100, thereby achieving the effect of retaining oil.

Fig. 6 is a flow chart showing a method of manufacturing the bearing device shown in Fig. 2. First, a bearing mold (not shown) is provided, and a mixture of the metal powder and the molten binder is injected into the bearing mold by injection molding to form the embryo body of the bearing body 10 and the embryo body of the upper cover 20, respectively. Next, the body of the bearing body 10 and the binder in the body of the upper cover 20 are removed by a degreasing or extraction method. After the degreasing process, since the binder is removed, the embryo body of the bearing body 10 and the embryo body of the upper cover 20 tend to be relatively loose, and the embryo body of the bearing body 10 and the embryo body of the upper cover 20 need to be sintered to be deformed. It is more dense to obtain high-density, high-strength products. According to different embryo bodies of the bearing body 10 and the body material of the upper cover 20, high-temperature sintering can be performed under an atmosphere of vacuum, oxygen or nitrogen. After sintering, the body of the bearing body 10 will undergo shrinkage deformation, and the body of the bearing body 10 and the body of the upper cover 20 may be dimensionally finished by mechanical processing. There are various common machining methods, such as broach dressing, bit dressing, grinding, numerical control, etc., and the body of the bearing body 10 and the body of the upper cover 20 can be mechanically finished by chemical etching or electrolytic discharge. The bearing body 10 and the upper cover 20 are obtained. The obtained upper cover 20 is pre-assembled to the inclined surface 112 of the bearing body 10 through the assembly surface 230, and the upper cover 20 and the bearing body 10 are fixed together by sintering, thereby obtaining the bearing device 100 of the present invention. The bearing device 100 is formed by injection molding of metal powder, has high shape freedom, can obtain parts close to the final shape to the utmost, and effectively reduces the amount of subsequent processing, and is more favorable for manufacturing high melting point and high relative to other forming methods. Parts with strength and complex shape are easy to automate and mass production.

Figure 7 is a cross-sectional view showing a second embodiment of the bearing device of the present invention in a specific application. The difference between this embodiment and the previous embodiment is that the upper cover 20 extends downwardly from the inner periphery of the through hole 210 to form a guiding portion 25. The guiding portion 25 can be separately molded by metal powder and then connected to the upper cover 20 by sintering. The guiding portion 25 can guide the lubricating fluid rising to the tip end of the bearing body 10 downward, thereby further preventing the lubricating fluid rising to the tip end of the bearing body 10 from being splashed by the perforation 210 of the upper cover 20 to the outside of the bearing device 100.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims.

100. . . Bearing device

10. . . Bearing body

20. . . Upper cover

11. . . Groove

12. . . Ring groove

13. . . Guide surface

14. . . Barrier

15. . . Opening

16. . . Oil guide

17. . . Shaft hole

18. . . Through hole

twenty one. . . Top wall

twenty three. . . Side wall

25. . . Guide

110. . . flat

112. . . Bevel

210. . . perforation

230. . . Assembly surface

30. . . Bushing

40. . . Rotating shaft

50. . . First oil storage space

60. . . Second oil storage space

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective assembled view of a first embodiment of a bearing device of the present invention.

Fig. 2 is an exploded perspective view of the bearing device shown in Fig. 1.

Fig. 3 is an inverted view of the bearing device shown in Fig. 2.

Figure 4 is a longitudinal cross-sectional view showing the specific application of the bearing device of the present invention.

Figure 5 is a longitudinal cross-sectional view showing another angle of the bearing device of the present invention in a specific application.

Figure 6 is a flow chart of a method of manufacturing a bearing device of the present invention.

Figure 7 is a longitudinal cross-sectional view showing a second embodiment of the bearing device of the present invention in a specific application.

Claims (10)

A method of manufacturing a bearing device, comprising the steps of:
Providing a bearing mold;
Injecting a mixture of the metal powder and the molten binder into the bearing mold to form an embryo body of the bearing body and an embryo body of the upper cover;
Removing the binder of the body of the bearing body and the body of the upper cover;
Sintering the embryo body of the bearing body and the embryo body of the upper cover to obtain a bearing body and an upper cover;
The upper cover is assembled on the bearing body to form the bearing device. The method of manufacturing a bearing device according to the first aspect of the invention, wherein the binder of the body of the bearing body and the body of the upper cover is removed by a thermal degreasing or extraction method. The manufacturing method of the bearing device according to the first or the second aspect of the invention, wherein the body of the bearing body and the body of the upper cover are sintered, and then the body of the bearing body and the body of the upper cover are trimmed to obtain a body. Bearing body and an upper cover. The method of manufacturing a bearing device according to claim 3, wherein the body of the bearing body and the body of the upper cover are trimmed using a machining method. The method of manufacturing a bearing device according to claim 1, wherein the upper cover is assembled on the bearing body and then sintered together to form the bearing device. The method of manufacturing a bearing device according to claim 1, wherein the bearing body is provided with a shaft hole for receiving a rotating shaft, and a lubricating fluid is disposed between the rotating shaft and the bearing body, and the bearing body is laterally oriented. The inner recess forms an oil guiding groove, and the oil guiding groove extends downward from a central portion of the bearing body to a bottom end of the bearing body. The oil guiding groove is provided with a through hole communicating with the shaft hole, and the rotating shaft rotates to drive the lubricating fluid from the shaft. The hole rises to establish a dynamic pressure between the rotating shaft and the bearing body, and a part of the lubricating fluid between the rotating shaft and the bearing body passes through the through hole and flows through the guiding of the oil guiding groove to the bottom end of the bearing body, and then flows back to the shaft hole. The bottom end reciprocates, and the upper cover blocks the lubricating fluid flowing to the top end of the bearing body. The method of manufacturing a bearing device according to claim 6, wherein a circumference of the bearing body extends upward to form a sloped surface, the upper cover includes a top wall and a cylindrical side wall extending downward from a periphery of the top wall The top wall is provided with a through hole for the rotating shaft, and the bottom end of the side wall forms an assembly surface corresponding to the inclined surface of the bearing body, and the upper cover is pre-assembled to the inclined surface of the bearing body through the assembly surface, and then sintered The upper cover is fixed to the bearing body. The method of manufacturing a bearing device according to claim 7, wherein the top wall extends downwardly at an inner edge of the perforation to form a guiding portion, and the guiding portion directs a lubricating fluid flowing to a tip end of the bearing body The lower end of the bearing body flows into the shaft hole, and the bottom end of the bearing body is provided with an opening at a position below the oil guiding groove, and the lubricating fluid flows back from the opening to the bottom end of the shaft hole. The manufacturing method of the bearing device of claim 8, wherein the bearing device is disposed in a bushing, and opposite sides of the bottom surface of the bearing body respectively extend downward to form a retaining wall, The opening is formed between the ends of the two retaining walls, the two retaining walls and the bottom wall of the sleeve enclose a first oil storage space, and the lubrication in the first oil storage space during the rotation of the rotating shaft The fluid flows up the shaft hole. The method of manufacturing a bearing device according to claim 9, wherein a second oil storage space is formed between the two retaining walls and a side wall of the sleeve, and a part of lubricating fluid between the rotating shaft and the bearing body passes through The hole flows through the guide of the oil guiding groove to the second oil storage space, and then flows back to the first oil storage space by the opening to reciprocate.