JPS5894628A - Sintered oil-containing bearing and manufacture of the same - Google Patents

Abstract

PURPOSE:To prevent the bending of bearing holes by forming the inner diameter of the titled sintered oil-containing bearing large at the two or more positions mutually spaced apart in the axial direction. CONSTITUTION:Sintered oil containing bearings 81 and 82 are formed by providing a plurality of ring-shaped grinding undercuts 101 and 102 at mutually spaced apart in the axial direction of bearing holes 91 and 92. Accordingly, the bending of the bearing holes 91 and 92 is prevented by the undercuts 101 and 102 (positions having a large bearing inner diameter) mutually spaced in the axial direction in each of the sintered oil-containing bearings 81 and 82.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sintered oil-impregnated bearing and a method for manufacturing the same, which are further developed from the contents of the previously filed patent application No. 187445/1982.

There are various uses and methods of using this Yuzu oil-impregnated bearing manufactured by powder metallurgy, but two of the same bearings are sometimes used in parallel.

An example is the coreless morph shown in FIG. .2 is a resin support 5 and a trench.The resin support 5 is attached to the iron core 6, respectively.

By the way, conventionally, as the oil-impregnated bearing 1.2, a simple cylindrical bearing with a uniform cross-sectional shape in the axial direction has been used.

However, not only do these positioning variations occur, but also the sizes of the individual bearings 1.2 also vary. This made it difficult to avoid problems such as noise and shaft galling.

Therefore, the applicant of this application proposed a method of reducing the inner diameter of the bearing by making it smaller at both ends of the bearing and larger at the center in the narrow direction, so that one bearing can have the same function as two bearings. He first proposed oil-impregnated bearings (patent application 1982).
-187445 trap.

The oil-impregnated bearing 7 according to the above proposal is used, for example, in place of the bearing 1.2 in the coreless morph described above (Fig. 2), but although the oil-impregnated bearing 7 is integral as a whole, The separated end portions 7a, 7b perform the same function as independent conventional bearings 1.2.

In that case, in order to effectively perform such a function, it is necessary to have a central portion 7c with a large diameter, both end portions 7a with a small diameter,
It is necessary to set the diameter difference between 7b and 7b to 277 m or more.

By the way, in the oil-impregnated bearing 7 according to the above proposal, the bearing length was, for example, about 4 to 7n, and it was assumed that there would be contact at two places (that is, support at two places). There was only one location with a large diameter in the center of the bearing.

However, some of these Yuzu 41+ bearings have bearing lengths exceeding, for example, 30 crimson, and the problem of defects due to bending of the bearing hole was noticeable in such bearings. The inventors of this application have also conducted various studies regarding the bending of the bearing hole in bearings with long bearing lengths.
We have found that a specific method that extends the idea of the previous proposal is effective for solving this bending problem.

This invention solves the problem of bearing hole curvature based on this knowledge, and provides a new sintered oil-impregnated bearing in which the inner diameter of the bearing is enlarged at two points apart from each other in the axial direction, and The present invention provides a manufacturing method suitable for manufacturing the same.

Hereinafter, the content of the present invention will be explained in detail with reference to the attached FIGS. 3 to 6.

In the sintered oil-impregnated bearing 81.82 of the present invention, as shown in FIG. It has characteristics. Therefore, in each of these sintered oil-impregnated bearings 811, 82, there are a plurality of locations with a large bearing inner diameter (i.e., relief 101) at multiple locations apart from each other in the detailed direction.
．． 102), and these are the bearing holes 91
．． 92 from bending. This bearing hole 91.9
The mechanism of the anti-bending effect in No. 2 is unclear, but since these sintered oil-impregnated bearings 81 and 82 are manufactured by powder metallurgy, the above-mentioned relief No.
It can be considered that the shape with 01.102 has a preferable effect. This point will become clearer in future explanations. In addition, escape 101.1
The number of 02 is plural, and it is desirable to increase the number as the bearing length becomes longer.

Furthermore, among the bearings shown in FIGS. 3(,) and 3(b), one bearing 81 has a ring-shaped groove 11 on the outer circumferential portion of the bearing corresponding to the relief 101 on the inner circumferential side, and the other bearing 82 There is no corresponding groove. This depends on how the grooves 11a, 11b, and llc are provided on the outer peripheral surface of the sintered body as described below.

Sintered parts are usually manufactured through a powder compaction process, a sintering process, and a repressing process after sintering, but here, as shown in FIG. Ring-shaped grooves 11a, llb, and llc are formed on the outer circumferential surface of the center S in the axial direction (corresponding to the locations where reliefs 101 and 102 are provided). These grooves 11a, 1it
), 110 can be formed by cutting or by changing the shape of the die used during powder compaction. Note that these grooves 11
The size, shape, etc. of a11b, 110 can be appropriately selected depending on the size of the relief 101.102 of the bearing hole 91.92.

Then, such a sintered body 12 is compressed again in the usual manner, that is, by using a die 13, an upper bunch 14, a lower punch 15, and a core rod 16, as shown in FIG. Then, the outer diameter portion of the sintered body 12 and the grooves 11a, 1lb, and 11a portions move outward so as to follow the shape of the die 13. On the other hand, the bearing hole portion swells outward at the grooves 11a, 111b, and 110, and there are parts that hit the core rod 16 and parts that do not hit the core rod 16, which has a uniform cross-sectional shape in the narrow direction. A shape of 81.82 is obtained.

Next, the effects of the present invention will be clarified based on an actual prototype example.

There are three types of sintered bodies 12 as shown in FIGS. 6(a) to 6(,), namely (a): one in which two $11a are provided concentratedly in the center of the outer peripheral surface, (b): (c): The width of the groove 11a is wider than that of (a), and the valley grooves 11a are distributed over the entire outer peripheral surface; (c): the number of grooves t1b is 4; In the same way, we prepared samples that were distributed over the entire outer circumferential surface, and after repressurizing and correcting them using the method described above, we determined the variation width of each prototype using a specified plug gauge, and the results are shown in the following table. I got it.

Since the 9p variation in the case where 111a is not provided is about 50%, it is clear that the present invention has an effect of preventing bending of the bearing hole. In addition, the bearing inner diameter of the prototype is approximately 34mm, and the bearing length is 1.
The depth of 1a is about 0.5 sins.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of application of the conventional yuzu bearing, FIG. 2 is a diagram showing an example of application of the bearing of the present invention, and FIGS. A sectional view showing an embodiment of the 411 receiver, FIGS. 4(a) to 4(c) are sectional views showing each of the sintered bodies used in the manufacturing method of this invention, and FIG. 5 is a repressing step in this invention. 6(a) to 6(,) are half sectional views showing each of the sintered bodies for trial manufacture. 81.82... Sintered oil-impregnated bearing according to this invention, 9
1.92...Bearing hole, 101.102...
Relief, 11.11a, llb, 1lc---groove on outer circumferential surface, 12...Sintered body. Figure 1

Claims (1)

[Scope of Claims] (1) A sintered oil-impregnated bearing characterized in that the bearing inner diameter of the sintered oil-impregnated bearing is increased at two or more locations separated from each other in the axial direction. (2) In the case where a sintered oil-impregnated bearing with a large bearing inner diameter at two or more locations separated from each other in the axial direction is manufactured through a powder compaction process, a sintering process, and a repressing process after sintering, the sintering process As a later sintered body, the outer circumferential surface 77 of the bearing in the axial direction
41. A method for manufacturing a sintered oil-impregnated bearing, comprising: forming a ring-shaped bearing having two or more tiles in /, and compressing the sintered body under pressure in the repressing step. (8) The method for manufacturing a sintered oil-impregnated bearing according to claim 2, wherein in the repressurizing step, a core rod and die having a uniform cross-sectional shape in the axial direction are used.