JPH0556403B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a bearing device for a motor such as a brushless motor for audio equipment.

BACKGROUND TECHNOLOGY Brushless motors for audio equipment are often of a flat type, and an important technique is how to support the thrust load caused by the attraction force of a magnet.

Below is a diagram of a conventional brushless motor.
Explain an example. In FIG. 3, the housing 1 is provided with a thrust bearing 2 and a radial bearing 3 that support thrust loads. 4 is a shaft, 5 is a thrust screw, 7 is a stator unit having a stator coil 8, and 9 is a rotor unit including a magnet 10.

The radial load acting on the shaft 4 is transferred to the radial bearing 3.
The thrust load due to the magnetic attraction force exerted by the magnet 10 on the stator unit 7 is supported by the thrust bearing 2 via the shaft 4. Also,
The thrust screw 5 serves to position the shaft 4 in the longitudinal direction and to transmit the thrust load to the housing 1 in order to maintain a predetermined gap between the rotor unit and the stator unit.

Problems to be Solved by the Invention However, in the above configuration, the thrust bearing 2 that is in contact with the shaft 4 and supports its thrust load has sliding friction, and the thrust bearing 2 is abraded, and the abrasion powder is disposed in the immediate vicinity. Radial bearing 3
and deteriorate bearing performance. Further, in order to reduce the amount of wear on the thrust bearing 2, a thrust bearing whose contact area with the shaft 4 is increased has the disadvantage that the bearing load increases.

Thrust ball bearings can be considered as a solution to the above drawbacks. However, due to its structure, this bearing
A complicated structure is required to position the rotating part including the retainer that supports the ball.

Means for Solving the Problems The present invention solves such problems by providing a bearing structure that is inexpensive and has little wear. The ball bearing is press-fitted into the inner ring, with the distance from the inner ring end face to the inner ring groove being L, and the length of the press-fitting part of the spacer to be described later being l, with the relationship L>l. A thrust bearing with a spacer made of metal, resin, etc. whose outer diameter is set slightly smaller than the outer diameter of the ball bearing, and a thrust bearing configuration in which the ball ring supports the thrust load applied to the shaft through the spacer. It is.

Effect: With this configuration, the shaft can be stably supported by the ball bearing, and at the same time, the wear of the thrust bearing and the increase in frictional resistance described above are also eliminated. Further, even if grease leaks from the ball bearing due to the presence of the spacer, the spacer can prevent the grease from spreading further. Then, as described above, the spacer is press-fitted into the ball bearing and integrated. This facilitates assembly of the thrust bearing and prevents deformation of the inner race surface of the ball bearing.

Embodiment Hereinafter, a bearing device according to an embodiment of the present invention will be described.
This will be explained with reference to the drawings.

FIG. 1 shows a sectional view of a thrust bearing in a first embodiment of the present invention. In FIG. 1, 1 is a housing, 2 is a ball bearing, 3 is a radial bearing, 4 is a shaft, 5 is a thrust screw, and 6 is a spacer. The configuration of the embodiment shown in FIG. 1 other than the above is basically the same as the conventional example shown in FIG. 3. 1st
The feature of this embodiment is that the inner ring side surface of the ball bearing 2 does not directly receive the end surface of the shaft 4,
When the distance from the inner ring side surface of ball bearing 2 to the inner ring groove is L, and the press-fitted part of ball bearing 2 into the inner ring is l, there is a relationship L>l, and the outer diameter is set slightly smaller than the outer diameter of the ball bearing. A spacer 6 made of metal, resin, or the like is press-fitted into the inner ring of the ball bearing 2, and the end surface of the shaft 4 is supported by the spacer 6.

The operation of the thrust bearing constructed as described above will be described below with reference to FIGS. 1 and 2.

When the distance from the inner ring side surface of the ball bearing 2 to the inner ring groove is L, and the press-fitted part of the ball bearing 2 into the inner ring is l, there is a relationship L>l, and the outer diameter is slightly smaller than the outer diameter of the ball bearing 2. Spacer 6 made of set metal, resin material, etc.
By press-fitting the spacer 6 into the inner ring of the ball bearing 2, even if the lubricating grease sealed in the ball bearing 2 leaks, the outer diameter of the spacer 6 is set slightly smaller than the outer diameter of the ball bearing 2. When the shaft 4 rotates and the spacer 6 rotates at the same speed, the leaked grease moves the surface of the spacer 6 on the ball bearing 2 side toward the outer circumference due to centrifugal force, and flies into the housing 1 from the outer circumferential end. Therefore, it does not reach the contact area between the spacer 6 and the shaft 4.

Further, the length l of the press-fitted portion of the spacer 6 has the relationship L>l as described above. Thereby, when the press-fitting portion is press-fitted into the inner ring, deformation of the inner ring due to the press-fitting does not extend to the race surface of the inner ring. However, in the case of the relationship L>l, the press-fitted part is press-fitted to a position where it overlaps the race surface of the inner ring, and the part where the race surface of the inner ring is provided, that is, the part where the inner ring has a thin wall pressure, is Since the weak parts are press-fitted, the race surface of the inner ring is greatly deformed.

The presence of this spacer 6 allows the end face of the shaft 4 to be flat and easily manufactured. Furthermore, the relative dimensional relationship between the diameter of the shaft 4 and the inner ring diameter of the ball bearing 2 can be freely set.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view of a thrust bearing showing a second embodiment of the present invention. In this figure, components similar to those in FIG. 1 are designated by the same reference numerals. The difference from the configuration shown in Fig. 1 is that in order to maintain coaxiality between the shaft 7 and the spacer 6, a circular hole 1 with a diameter slightly larger than the shaft 4 is formed in the center of the lower part of the spacer 6.
1 is provided, and the upper end portion of the shaft 7 is fitted thereto. This maintains the coaxiality of the shaft 4 and the ball bearing 2, allowing the shaft 4 to rotate more stably.

Effects of the Invention As described above, in the present invention, when supporting the end face of a shaft with a ball bearing, the distance from the inner ring side surface of the ball bearing to the inner ring groove is L, and the length of the press-fitted part of the spacer described below into the inner ring is L. 1, a spacer made of metal, resin, etc. having the relationship L>l and having an outer diameter set slightly smaller than the outer diameter of the ball bearing is press-fitted into the inner ring, and the spacer is inserted into the inner ring through the spacer. By supporting the thrust support shaft with thrust rotation, even if the lubricating grease sealed in the ball bearing leaks, it does not reach the contact area between the spacer and the end surface of the thrust supported shaft, and Deformation of the inner ring of the ball bearing can be suppressed.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a thrust bearing according to a first embodiment of the present invention, Fig. 2 is a cross-sectional view of a thrust bearing according to a second embodiment of the present invention, and Fig. 3 is a cross-sectional view of a conventional thrust bearing. It is a diagram. 1...Housing, 2...Ball bearing,
3... Radial bearing, 4... Shaft, 5... Thrust screw, 6... Spacer, 11... Hole.

Claims (1)

[Scope of Claims] 1. It has a structure in which a ball bearing supports the thrust load due to the magnetic attraction force of a magnet transmitted to the shaft, and the distance from the inner ring side surface of the ball bearing to the inner ring groove is L, and the distance between the inner ring and the inner ring is L. When the length of the press-fit part of a spacer having a substantially press-fit part and a flange part is l, there is a relationship L>l,
The outer diameter of the flange portion of the spacer is set to be slightly smaller than the outer diameter of the ball bearing,
A bearing device for a motor, characterized in that the shaft is rotatably supported via the spacer. 2. The motor bearing device according to claim 1, wherein the spacer has a circular hole whose diameter is slightly larger than that of the shaft.