JPH0641768B2 - Processing method of sliding bearing - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding bearing used for bearings of a motor of an audio device such as a record player and a method of processing the same.

Conventional structure and its problems Conventionally, the motor of an audio device such as a record player is the first
As shown in the figure, a bearing 2 is mounted on a stator iron plate 1, a spindle shaft 3 is inserted into the bearing 2, and a turntable 5 with a rotor magnet 4 is placed on the spindle shaft 3. A printed circuit board 7 in which a stator coil 6 facing the rotor magnet 4 and a drive circuit for driving the motor are integrated is provided immediately below the rotor magnet 4.

When the motor configured as described above is started and the turntable 5 starts to rotate, the turntable 5 starts to rotate while performing a whirling motion as shown in FIG. During this whirling motion, the positional relationship between the bearing 2 and the spindle shaft 3 is moving as shown in FIG.

Here, generally, in the processing of the bearing 2, as shown in FIG. 4, the inlet portion 8 and the outlet portion 9 have poor roundness, are not smooth, and have large irregularities. When the shape is very bad as shown in the roundness measurement data of FIG. 5, when the spindle 2 rotates while contacting the bearing 2, the spindle 3 may roll on the saw teeth. At the same time, there is a drawback that it may cause uneven rotation of the spindle shaft 3, or in some cases, the damage between the spindle shaft and the bearing may become large and cause seizure.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide a method for processing a sliding bearing, which can improve rotation unevenness and seizure of a spindle shaft.

Structure of the Invention In order to achieve the above object, the present invention, in order to obtain a good surface roughness and a good roundness during the processing step of the bearing, first, as a pre-processing, the inner diameter of the cylindrical metal material to be the bearing. The predetermined length portions of the inlet portion and the outlet portion of each of them are tapered with a constant gradient, and the fitting portions of the inlet portion and the outlet portion other than the predetermined length with the spindle shaft have a uniform shape. In advance of the original Superoll process as a finishing process for the inner diameter surface, the Superoll tool is usually advanced over the entire length of the bearing at a constant rotation speed and a constant speed in the original Superoll process as a finishing process of the inner diameter surface. Although the Superoll tool is allowed to rotate at the boundary between the tapered section of the inlet section and the outlet section and the straight section, the Superoll tool advances in the axial direction. By temporarily stopping for a certain period of time, the surface roughness or the roundness of the inner surface at the boundary portion can be adjusted, and the roundness having the same high precision as that of the straight-shaped portion can be processed and finished.

Description of Embodiments FIGS. 6 and 7 show an embodiment of the present invention, in which 2 is a bearing, 10 is a Superoll, and 11 is a roller attached to the Superoll 10. In the tapered surface 12 of the bearing 2, the cutting burr at the boundary portion 14 between the tapered surface 12 and the straight surface 13 is reduced as much as possible during cutting, and the boundary portion 1 between the tapered surface 12 and the straight surface 13 is reduced.
Superoll 10 hits only 4 and has an inclination of about 30 ° set to eliminate the influence on other surfaces.
When the central portion of the roller 11 hits the boundary portion 14 between the straight surface 13 and the straight surface 13, stopping the feeding of the Superoll 10 in the downward direction causes pressure on the outside of the roller 11 and causes an upward pressure around the boundary portion 14. The roller 11 is in contact with only the boundary portion 14 at the lower side, and there is no force relationship with the other surface, that is, the surface 12 having 30 ° or the straight surface 13, and the roller can freely move to the boundary portion 14. It will be subjected to processing. As a result, the processing finish of the boundary portion 14 has no unevenness as shown in FIG. 8 and the roundness is improved.

When the processing of the inlet is completed as described above, the Superoll 10
Is again moved downward at a constant feed pitch, and when the Superoll 11 comes to the outlet of the bearing 2, it is processed again in the same way as the inlet. In this processing, the vertical axis represents time and the horizontal axis represents bearings. FIG. 9 is a graph showing a part of the Superoll tool temporarily stopped for a predetermined time with a machining length of 2.

Originally, Superoll processing is a method of crushing the eyes of a cutting tool generated on the cutting surface to finish the surface, so Superoll processing accuracy is determined by the dimensional accuracy before Superoll processing. Therefore, in this embodiment, in order to improve the dimensional accuracy of the inlet / outlet portion of the bearing 2, the straight surfaces 13 and 30 are used.
The roller 12 can be processed so as not to be forced by the surface 12 having an inclination of °.

In the case of the present embodiment, the material for the bearing 2 is a cylindrical brass (BsSM) having an inner diameter of 7 mm, an outer diameter of 12 mm, and a length of 22 mm. Implemented at the lower entrance, Superoll tool rotation speed is 850
I chose 1 second for rpm and pause time.

However, when the present invention is carried out, the material is not necessarily restricted by the above conditions, and the material is gun metal (BC ₆ ) as well.
Alternatively, not only other brass type but also iron type may be applied.

The inner and outer diameters and lengths of the bearings also differ depending on the applied motor, and the number of revolutions, taper gradient, etc. of the Superoll tool that makes the surface roughness or roundness of the inner diameter surface a preferable value as the inner and outer diameters change Can be appropriately determined by design.

As described above, according to the present invention, even when the spindle shaft comes into contact with the boundary between the inlet / outlet portion of the bearing and the straight surface due to the whirling motion of the spindle shaft generated in the bearing when the motor is started. , Has no effect on the spindle axis,
As a result, there is an advantage that it is possible to eliminate the cause of uneven rotation of the spindle shaft (and eventually uneven rotation of the record player) and burning.

[Brief description of drawings]

Fig. 1 is a front view of a motor used in a record player, Fig. 2 is a front view of the motor swinging when the motor is started, and Fig. 3 is whirling in a bearing formed by the motor. FIG. 4 is a plan view showing the trajectory of the moving spindle shaft, FIG. 4 is a cross-sectional view of the bearing, and FIG. 5 is a diagram showing the roundness measurement data in the shape of the inlet portion of the bearing by the conventional processing method. FIG. 7 is a front view of a Superoll stopped state by a processing method according to an embodiment of the present invention, FIG. 8 is a diagram showing circularity measurement data in the shape of an inlet portion obtained by the processing of the same embodiment, and FIG. The figure shows the relationship between the processing time of the roller and the processing length of the bearing in Superoll processing. 2 ... Bearing, 10 ... Superoll, 11 ... Roller, 12 ... Tapered surface, 13 ... Straight surface, 14 ...
… Boundary.

Claims (1)

[Claims] 1. A predetermined length portion of an inlet and an outlet of an inner diameter of a cylindrical metal material which serves as a bearing has a tapered shape with a constant gradient, and has a spindle shaft other than the predetermined length of the inlet and the outlet. The mating part of is preliminarily processed by cutting so that it has a uniform straight shape, and Superoll processing is used as the finish processing of the inner diameter surface. In the portion, rotation of the Superoll tool is performed, but the progress of the Superoll tool in the axial direction is temporarily stopped for a predetermined time so that the tapered portion of the inlet portion and the outlet portion and the straight portion are It is necessary to machine and finish the inner diameter roundness of the boundary portion with high accuracy almost equal to the inner diameter surface finishing accuracy of the above straight shape portion. Processing method of sliding bearings and butterflies.