JPS60200902A - Bearing manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a bearing, and particularly to a method of manufacturing a bearing having a long dimension in the axial direction and used in precision rotating equipment such as a micro motor.

This type of bearing replaces the two normally used bearings.
Since it is integrally formed and has a long dimension in the axial direction, it is difficult to maintain the accuracy of the shaft hole in terms of straightness and hole diameter to the exact same angle, resulting in high costs. Furthermore, since the contact area with the shaft is large, bearing friction loss is large, which impairs the efficiency of rotating equipment.

Therefore, in order to solve the above problem, conventionally, as shown in FIG. Due to the generated strain, the thin portions 3 of the four circumferential portions 1 are moved outward, and a large diameter portion 5 is formed in the longitudinal middle portion of the shaft hole 4.

However, in the conventional bearing manufacturing method described above, there is a risk that mechanical strength is insufficient due to the presence of the thin wall portion 3, and alignment errors of the journal portions 4a and 4b may occur due to changes over time during use.

The present invention has been proposed in view of the above, and an object of the present invention is to provide a bearing manufacturing method that easily and at low cost manufactures a bearing having a large diameter portion, that is, four portions that do not contact the shaft, in the center of a long journal. do.

Embodiments of the present invention will be described below with reference to the drawings. Figure 3 shows the original form of the core vibro for forming the journal, which is made of a straight shape memory alloy. This core vibro has a longitudinal middle part swollen by bulge processing as shown in Fig. 4, and both ends 6a are cut into a hole diameter to support a shaft (not shown). Reference numeral 6b is for molding the four parts in the middle part of the journal.

Figure 5 shows the bearing 7 using the core vibro shown in Figure 4 above.
This figure shows a mold for producing a mold, in which a molding space 111. is formed by an upper mold 8, a middle mold 9, and a lower mold 10. The inside is filled with sintered metal through a passage (not shown).

After forming the bearing 7, by preheating or sintering the bearing 7, the core vibro returns to its original straight shape with the same overall length and diameter as shown by the chain line in FIG. 5, and can be removed from the bearing 7. Next, the journal surface of the bearing 7 is adjusted for accuracy using a sizing arbor (not shown), and as shown in FIG. This completes a bearing that achieves 2 and 1.

As described in detail above, according to the present invention, the molded bearing does not have extremely thin parts, so it has high strength and there is no possibility of misalignment of the shaft hole due to changes over time during use. In addition, in the conventional manufacturing method, the axial position of the thin outer diameter portion is restricted by the flange 2a, and the optimum length of the journals 4a, 4b at both ends of the bearing cannot be arbitrarily set (for example, the length of the journal 4a cannot be set arbitrarily). Even if you try to make it shorter than the illustrated example, it is not possible to cut the four circumferential parts l because of the flange 2a.)
However, the manufacturing method of the present invention does not have such restrictions. Therefore, there is an effect that a high-precision bearing can be manufactured easily and at a low cost.

In the above embodiment, the core vibro was made of a single shape memory alloy, but as shown in FIG. It may be made of a memory alloy, and the rest may consist of a separate mandrel.

FIG. 8 illustrates a rotating electric machine to which a bearing obtained by the manufacturing method of the present invention is applied. In FIG. 8, 13 is a motor case, and the bearing 7 obtained by the above-described manufacturing method of the present invention is attached to the center of the motor case. 14 is a field magnet provided on the inner surface of the motor case 13; 15 is a rotor shaft supported through the bearing 7; 16 is a cylindrical body attached to the rotor shaft 15; the large diameter cylindrical portion at one end is connected to the bearing 7; It is placed on the outside of 7. 17 is a rectifier provided in the small diameter cylindrical portion of the cylindrical body 16;
8 is an armature core laminated and fixed to the cylinder body 16, 19 is an armature coil wound around the armature core 18, 20 is a spark extinguishing element, and 21 is a motor end cover that is attached to and removed from the opening of the motor case 13. , 22 is a thrust receiver provided at the center of the motor end cover 21 to receive the end of the rotor shaft 15, 23 is a brush lonker plate provided on the inner surface of the motor end cover 21, and 24 is a brush.

[Brief explanation of drawings]

Figures 1 and 2 are longitudinal cross-sectional views of a bearing manufactured by a conventional manufacturing method, Figure 3 is a vertical cross-sectional view of a core pipe before deformation applied to the present invention, and Figure 4 is a longitudinal cross-sectional view of the core pipe after deformation. FIG. 5 is a vertical cross-sectional view of a mold showing the manufacturing force U of the bearing of the present invention, FIG. 6 is a vertical cross-sectional view of a bearing manufactured by the manufacturing method of the present invention, and FIG. [11r-IF showing a modified example of the pipe
FIG. 8 is a longitudinal sectional view, partially cut away, of a rotating electric machine to which a bearing manufactured according to the present invention is applied. 6 is the core pipe, 7 is the bearing. Figure 3 Figure 4 Figure 8

Claims (1)

[Claims] (1) After forming a bearing using a core made by swelling the middle part of a straight shape memory alloy, this bearing is preheated or sintered, and this heating causes the middle part to swell before being formed. A method for manufacturing a bearing, comprising removing the shape memory alloy that has returned to its original shape from the bearing.