JPS59490Y2 - Sintered oil-impregnated bearing - Google Patents

Description

[Detailed Description of the Invention] This invention provides sintered oil-impregnated bearings (hereinafter sometimes simply referred to as bearings) for housings of various devices.

) is fixed by press-fitting and caulking, and the installation is related to a bearing structure that prevents the distortion of the inner diameter of the bearing that sometimes occurs, and is particularly important for relatively small bearings such as those for micro motors. It is useful.

The case of a micromotor will be explained below as an example.

Figure 1 shows the process of attaching the bearing to the motor case.The case 20 is made by pressing a steel plate.
Main body part 21 housing rotor 30 and sintered oil-impregnated bearing 10
A housing portion 22 is formed to which the housing is attached.

The outer diameter of the bearing 10 and the inner diameter of the housing portion 22 are set to have a dimensional difference that provides a tight fit sufficient to secure the bearing, and the force required to press-fit the bearing is, for example, 30 to 90 kg.

After press-fitting, peel off the end of the housing part to complete the bearing installation.

The problem here is that the compression of the outer diameter due to press-fitting and tightening causes deviations in the inner diameter of the bearing.

Although the distortion itself can be corrected by machining, it will increase the amount of man-hours, and furthermore, it is necessary to avoid affecting the condition of the pores on the bearing surface due to correction machining in micromotor bearings where noise is an important quality issue. .

This invention was made for the purpose of solving the above-mentioned problems, and its gist is to provide an annular groove as illustrated in FIGS. 2 and below on at least one end surface of the bearing.

The following table compares how the inner diameter changes with and without an annular groove for bearings with an inner diameter of 3 mm, an outer diameter of 8 mm, and a length of 6 mm. clearly shown.

The shape of the groove may be a ■-shape as shown in FIG. 2, or a U-shape as shown in FIG.

Its dimensions depend on the size of the bearing, but generally the width is 0.3
-1 mm, and the depth should be 0°3 to 1.5 mm.

In the above example, the annular groove is provided on both the upper and lower end surfaces of the bearing as shown in FIG. 4, but it is usually sufficient to provide it on either end surface (in most cases, the caulking side).

However, the annular groove can be formed by simply providing an annular protrusion on the forming punch and does not significantly affect the cost, so it is convenient to provide it on both sides to save the effort of determining the press-fitting direction.

Note that depending on the size of the bearing and the tightness, it may be better to provide double annular grooves.

[Brief explanation of drawings]

FIG. 1 is a drawing explaining the purpose of the present invention, and FIGS. 2 to 4 are drawings showing an embodiment of the present invention. 10... Sintered oil-impregnated bearing, 11.12... Annular groove, 2
0...Motor case, 21...Main body, 22...
・Housing part, 30... rotor

Claims (1)

[Scope of utility model registration request] In a bearing device consisting of a housing that holds a bearing and a bearing fixed to the housing by press fitting and caulking, the bearing is a sintered oil-impregnated bearing, and an annular groove is provided on at least one end surface of the bearing device. Characteristic bearing device.