JPS6081514A - Bearing device - Google Patents

Abstract

PURPOSE:To extend life of a bearing, by a method wherein a thrust load to be applied to a shaft is negated by applying force in a negative direction of a thrust load to a thrust bearing through a pressing device. CONSTITUTION:A thrust load to be applied to a rotary shaft 9 is supported by a thrust bearing 11, force offsetting the thrust load is applied to the thrust bearing 11 through a pressing device constituted with a bearing plate 20, a wave washer 21 and a supporting plate 22. Prepressing is applied to two radial bearings 10a, 10b through prepressing plate 17, the wave washer 18 and a prepressing ring 19 under such state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a bearing device that can be used to rotate a shaft that receives a thrust load with high precision and high rigidity without reducing the life of the bearing. .

Conventional structure and its problems In recent years, compact devices that can rotate the shaft with very high precision while suppressing shaft vibration, such as those seen in parts of the cylinder of video tape recorders (hereinafter abbreviated as VTR), have been developed. bearing devices are needed and are being put into practical use.

Hereinafter, a conventional bearing device will be described with reference to the drawings, taking as an example a bearing for a portion of a cylinder of a VTR. FIG. 1 is a partial schematic sectional view of a part of a VTR cylinder, in which there is a rotating shaft, radial bearings 2a and 2b, and a three-piece housing. An upper cylinder 8 is press-fitted into the rotating shaft 1 and rotates therewith. The rotating shaft 1 is rotatably supported by radial bearings 2a and 2b installed in the housing 3, but in order to suppress the vibration of the shaft, upper 7 renoders 8,
Sleeve 4, preload holder 6, wave washer 6,
The preload boss 7 applies preload to the radial bearings 2a, 2b.

In the bearing device configured as described above, by applying preload using a radial bearing, it is possible to rotate the shaft with high precision while being small.

However, in a VC with the above configuration, when a thrust load is applied to the shaft, the load is applied to one of the bearings, which not only increases the rotational friction torque but also shortens the bearing life. However, there is a problem in that it is difficult to apply an appropriate preload to each bearing.

OBJECTS OF THE INVENTION An object of the present invention is to provide a bearing device that can rotate and heat a 1ζh receiving thrust load with high precision without reducing the life of the bearing.

Structure of the Invention The bearing device of the present invention comprises a shaft that rotates around the shaft center line, a radial bearing means that supports the shaft in the radial direction via rolling elements, and a thrust bearing that supports the above-mentioned Iql+ in the axial direction. and a pressurizing means that applies a force to the thrust bearing in the axial direction, and a housing that supports the shaft via the radial bearing and the thrust bearing, and applies the thrust load applied to the shaft to the thrust bearing in item 111. The thrust load is canceled out by applying a force in the opposite direction to the thrust load using the pressure means, and a preload (=J) is applied to the radial bearing means. It can be rotated with high precision using a small bearing configuration without any movement.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows a part of a rotary actuator (drive source) in an embodiment of the present invention. In FIG. 2, 9 is the rotation side 1, IQ2L.

10b is a radial bearing that supports the shaft in the radial direction, 11 is a thrust bearing that supports the shaft in the axial direction, and 12 is a housing. In this embodiment, a circular permanent magnet 14 is bonded to a rotary plate 13 that is press-fitted into a rotating plate 1qII 9, and a magnetic flux is generated between it and a back yoke 16 on the housing 12 side. By sequentially passing current through the coil 16, the rotating plate 13, that is, the rotating shaft 9, rotates around the axis center line, but the rotating shaft 9 rotates with high precision and high rigidity in order to prevent shaft vibration. I have to.

In the rotary actuator configured in this way, a magnetic attraction force acts between the permanent magnet 14 and the back yoke 16,
As a result, it rotates via the rotating plate 13! A thrust load is applied to 1!1II9. If this thrust load is not supported by the inner ring of the radial bearing 10a, an excessive thrust load that exceeds the appropriate preload load will be applied to the radial bearing, making it impossible to rotate the rotating shaft 9 with high precision and high rigidity. This results in a reduction in bearing life and an increase in rotational friction torque.

Therefore, in this embodiment, this thrust load is supported by the thrust bearing 11, and the bearing plate 20. Wave Wono/Ya21. The thrust bearing 11 is
A force is added to offset the thrust load. In this state, the preload plate 17. Wave washer 18. A preload ring 19 applies preload to the two noradial bearings 10a, 1c)b.

As described above, according to this embodiment, the thrust load acting on the rotating shaft is canceled by the thrust bearing, and by adding an appropriate preload to the radial bearing, the rotating shaft can be made with high precision and high rigidity by suppressing shaft runout. It allows you to rotate,
It is possible to achieve t:1 formation without reducing l+ service life.

Effects of the Invention As is clear from the above explanation, in the present invention, the shaft receiving the thrust load is supported by the radial bearing means and the thrust bearing.
By applying preload to the radial bearing, the shaft can be rotated with high accuracy and high rigidity, and the effect of preventing the bearing life of the radial east 11 bearing from being shortened due to excessive thrust loads can be obtained.

Further, in the configuration of the present invention, since the radial 1111 bearing does not receive thrust load, a small 1lqI+ bearing can be selected, and the effect that a compact bearing device can be realized as a whole can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a portion of a cylinder of a VTR using a conventional bearing device, and FIG. 2 is a cross-sectional view of a main portion of an example of a rotary actuator using the bearing device of the present invention. 9... Rotating shaft, 10a, 10b... Radial bearing, 11... Thrust bearing, 12...
... Housing, 20 ... Bearing plate, 21 ...
- Wave washer, 22...Support plate.

Claims (2)

[Claims] (1) A shaft that rotates around the shaft center line, a radial bearing means that supports the shaft in the radial direction via rolling elements, a thrust bearing that supports the shaft in the axial direction, and a radial bearing means that supports the shaft in the axial direction, and and a housing that supports the shaft via the radial bearing and the thrust bearing, the thrust load applied to the shaft is applied to the thrust bearing in a direction opposite to the thrust load by the pressing means. What is claimed is: 1. A bearing device characterized in that the bearing device is configured to cancel the force by applying the force. (2) The bearing device according to claim (1), wherein a preload is applied to the radial bearing means.