JPH05199729A - Bearing structure of stepping motor - Google Patents

Abstract

PURPOSE:To provide the inexpensive bearing structure of a stepping motor little in noise and vibration by making it of a bearing member, which engages with the rotary shaft, and resin member. CONSTITUTION:The bearing structure 1 of a stepping motor has a stepping motor 2 and a frame 4, which is made of resin member and is provided with a bearing 3, and the top 5a of the rotary shaft 5 is made spherical. Moreover, the bearing part 3 is provided with a hole 3a with a diameter a little larger than that of the top 5a of the rotary shaft 5, and the bottom of the hole supports the load of the rotary shaft, and the inside periphery supports the load in the diametrical direction of the rotary shaft. And, a small diametrical gap 8 lies between the top 5a of the rotary shaft 5 and the inside periphery of the hole 3a of the rotary shaft 3, and the rotary shaft 5 is engaged rotatably by the hole 3a of the bearing and a metallic bearing 9. Moreover, a spiral groove 7 is made at the periphery of the section projecting from the stepping motor 2 of the rotary shaft 5, and an engaging member, which engages with the groove 7 by the rotation of the rotary shaft 5, is rocked in axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing structure of a stepping motor for electronic equipment such as a VTR camera.

[0002]

2. Description of the Related Art A stepping motor for a VTR camera will be described as an example of electronic devices such as a VTR camera and a floppy disk drive device.

Focusing and zooming of an image of a VTR camera are generally performed by moving a lens, and a stepping motor is used as a driving source of the lens. Hereinafter, a brief description will be given with reference to FIG.

In FIG. 7, a lens unit 20 of a VTR camera has a lens frame 21, a moving lens 22 and a fixed lens 23. By swinging the moving lens 22 in the axial direction of the lens unit 20, image focusing and focusing are performed. I am zooming.

The bearing structure 1 of the stepping motor attached to the lens unit 20 includes a stepping motor 2
And a frame 4 provided with a pivot bearing 11.

The rotary shaft 5 of the stepping motor 2 is pushed by a pivot bearing 11 by a spring 6 provided on the stepping motor 2 so as to be restricted from moving in the axial direction, and at the same time, a metal bearing provided on the pivot bearing 11 and the stepping motor 2. It is rotatably engaged by 9 and.

A spiral groove 7 is formed on the outer peripheral surface of the portion of the rotary shaft 5 projecting from the stepping motor 2, and an engaging member 12 that engages with the groove 7 by the rotation of the rotary shaft 5 is provided on the rotary shaft 5. Swing in the axial direction.

The other end of the engaging member 12 is connected to the moving lens 22, and the moving lens 22 swings in the axial direction of the lens unit 20 in accordance with the swing of the engaging member 12 to form a VTR.
Focus and zoom the camera image.

The characteristics required for a VTR camera are low noise and low vibration. This is because the noise generated from the VTR camera itself is recorded, or the vibration makes the operating person uncomfortable. Naturally, the VTR camera stepping motor is also required to have low noise and low vibration.

Originally, the main cause of noise and vibration of the stepping motor was damping vibration of the rotor. this is,
In recent years, the motor has become so small that it does not pose a problem in recent years due to improvements in the drive circuit and VTR camera body.

As a result, the main causes of noise and vibration of the stepping motor are noise and vibration caused by sliding of the rotary shaft and the pivot bearing and rolling of balls in the pivot bearing, and vibration of the rotary shaft from the pivot bearing to the frame. It became the noise and vibration transmitted to the VTR camera through.

[0012]

However, in the conventional bearing structure of the stepping motor, noise and vibration due to sliding of the rotary shaft and the pivot bearing and rolling of balls in the pivot bearing, and vibration of the rotary shaft are generated from the pivot bearing. There was a problem that noise and vibration transmitted to the VTR camera via the frame were large. Moreover, there is a problem that the pivot bearing is expensive due to its complicated structure and the stepping motor is also expensive.

Therefore, the present invention solves such a problem, and an object thereof is to provide an inexpensive bearing structure for a stepping motor with less noise and vibration.

[0014]

The bearing structure for a stepping motor according to the present invention is as follows: 1. A stepping motor comprising at least a frame provided with a bearing portion and a stepping motor having a rotary shaft engaging with the bearing portion. In the bearing structure of No. 2, the bearing portion is made of a resin member, the frame is made of a resin member, and the bearing portion is integrally formed on a part of the frame. In the third aspect, the sphere is arranged, and the radial and axial loads by the rotating shaft or the sphere are supported by the same portion of the bearing portion.

[0015]

Embodiments of the bearing structure of a stepping motor according to the present invention will be described below with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, a bearing structure 1 for a stepping motor has a frame 4 provided with a stepping motor 2 and a bearing portion 3 formed of a resin member.

The rotating shaft 5 of the stepping motor 2 is pushed by the bearing portion 3 by a spring 6 provided on the stepping motor 2 and is restricted from moving in the axial direction.

The tip 5a of the rotary shaft 5 is formed in a spherical shape.

The bearing portion 3 is provided with a hole 3a having a diameter slightly larger than the diameter of the tip portion 5a of the rotary shaft 5. The bottom of the hole has a load in the axial direction of the rotary shaft and an inner peripheral surface of the hole. Supports the radial load of the rotating shaft. There is a slight radial gap 8 between the tip 5a of the rotary shaft 5 and the inner peripheral surface of the hole 3a of the bearing portion 3.

The rotary shaft 5 is rotatably engaged by a hole 3a in the bearing portion and a metal bearing 9 provided in the stepping motor 2.

A spiral groove 7 is formed on the outer peripheral surface of the portion of the rotary shaft 5 protruding from the stepping motor 2, and an engaging member (not shown) engaged with the groove 7 by the rotation of the rotary shaft 5 is provided on the rotary shaft 5. Swing in the axial direction of.

Table 1 shows the magnitudes of noise and vibration of the entire electronic device when the bearing structure of the stepping motor according to the first embodiment of the present invention and the conventional bearing structure of the stepping motor are incorporated. 5 is a table comparing noise and vibration magnitudes other than those of stepping motors.

In Table 1, large, medium, and small represent noise, vibration, which are large, medium, and small, respectively, when the levels of noise and vibration are divided into three levels.

There are three levels of noise / vibration other than the stepping motor of electronic equipment: large / medium / small. Noise and vibration of the stepping motor are large in the conventional structure / small in the structure of the present invention. There are two levels.

[0026]

[Table 1]

It is clear from Table 1 that the noise and vibration of the entire electronic device incorporating the stepping motor must be small unless both the noise and vibration of the stepping motor and the noise and vibration of parts other than the stepping motor are small.

Regarding the noise and vibration of the stepping motor, the noise and vibration of the stepping motor having the structure of the present invention are smaller than those of the conventional stepping motor.

Regarding the noise and vibration of the entire electronic equipment, the electronic equipment incorporating the stepping motor having the structure of the present invention is smaller in noise and vibration than the electronic equipment incorporating the stepping motor having the conventional structure.

In particular, when the noise and vibration other than the stepping motor of the electronic device are small, the electronic device incorporating the stepping motor of the present invention has a noise and vibration as compared with the electronic device incorporating the stepping motor of the conventional structure. Is small.

The bearing structure of the stepping motor of the present invention is capable of reducing noise and vibration of electronic equipment as compared with the conventional structure.

Moreover, since the bearing portion 3 made of a resin member has a simple structure, it can be manufactured at a low cost, so that the cost of the stepping motor becomes low.

A second embodiment of the present invention will be described with reference to FIG.

In FIG. 2, the bearing portion 4a and the frame 4
Except for this point, the configuration is the same as that of the first embodiment, so description thereof will be omitted.

The frame 4 is made of resin material.
The bearing portion 4a is integrally formed with a part of the.

A third embodiment of the present invention will be described with reference to FIG.

In FIG. 3, the structure is the same as that of the first embodiment except that the ball 10 is arranged between the bearing 3 and the tip 5b of the rotary shaft. Descriptions other than those are omitted.

A recess is formed at the tip 5b of the rotating shaft, and a sphere 10 having a smooth surface is arranged between the recess and the hole 3a of the bearing portion.

In the first embodiment, the smoother the surface of the spherical portion of the tip end portion 5a of the rotary shaft that applies a load in the axial direction to the bearing portion 3 and slides, the smaller the noise and vibration. However, it is difficult to form a spiral groove on the outer peripheral surface of the rotary shaft and to smooth the surface of the spherical portion of the tip. Therefore, by disposing the sphere 10 having a smooth surface between the bearing portion 3 and the tip 5b of the rotary shaft, the surface of the portion that slides by applying an axial load to the bearing portion can be easily made, Noise and vibration can be reduced. Sphere
It is a general-purpose small bearing ball that can be obtained inexpensively and quickly.

A fourth embodiment of the present invention will be described with reference to FIG.

In FIG. 4, except for the bearing portion, the structure is the same as that of the first embodiment, and therefore the description other than the bearing portion will be omitted.

At the bottom of the hole 3a of the bearing 3, a hole 3b smaller than the diameter of the tip 5a of the rotary shaft is provided. The rotating shaft 5 and the sphere 10 pushed by the spring 6 into the hole 3a of the bearing portion hit the corner 3c of the hole 3b and are supported in the axial direction and the radial direction of the rotating shaft.

In the first embodiment, the tip portion 5 of the rotary shaft is
Since there is a slight radial gap 8 between a and the inner peripheral surface of the hole 3a of the bearing portion, the rotary shaft rattles by the amount of the gap 8 in the radial direction. This rattling generated noise and vibration that were extremely small.

In this embodiment, the rotating shaft is the corner 3 of the hole of the bearing.
Since it is supported by c in the axial direction and the radial direction, the rotary shaft does not rattle in the axial direction and the radial direction. Therefore, it is possible to eliminate noise and vibration caused by the rotational shaft rattling in the radial direction.

The hole 3b of the bearing portion may be a through hole or a bottomed hole.

A fifth embodiment of the present invention will be described with reference to FIG.

In FIG. 5, except for the bearing portion, the structure is the same as that of the fourth embodiment, and therefore the description other than the bearing portion will be omitted.

The bearing portion 3 has an inclined surface 3d that engages with the tip portion 5a of the rotating shaft 5 and the ball 10.

The tip portion 5a of the rotary shaft and the ball 10 which are pushed by the bearing portion 3 by the spring 6 hit the slope 3d and are supported in the axial direction and the radial direction of the rotary shaft. No rattling in the radial direction. Therefore, it is possible to eliminate noise and vibration caused by the rotational shaft rattling in the radial direction.

The inclined surface 3d may be provided in all or a part of the tip end of the rotary shaft and the sphere.

A sixth embodiment of the present invention will be described with reference to FIG.

In FIG. 6, the structure is the same as that of the fourth embodiment except for the tip portion 5c of the rotary shaft, and therefore the description is omitted except for the tip portion of the rotary shaft.

An inclined surface is formed at the tip 5c of the rotary shaft 5, and the tip 5c of the rotary shaft pressed by the spring 6 onto the bearing 3 is formed at the corner of the hole 3b at the bottom of the hole 3a of the bearing 3. 3c
It is supported in the axial direction and the radial direction of the rotating shaft.

Since the rotary shaft is supported in the axial direction and the radial direction by the angle of the hole of the bearing portion, the rotary shaft does not rattle in the axial direction and the radial direction. Therefore, it is possible to eliminate noise and vibration caused by the rotational shaft rattling in the radial direction.

Regarding the implementation of the present invention, even when the first to sixth embodiments of the above-described embodiment are combined and implemented, the same effect as described above can be obtained.

[0056]

The bearing structure of the stepping motor of the present invention has the following remarkable effects.

Since the bearing portion is made of the resin member, compared with the bearing structure of the stepping motor of the prior art in which the bearing portion is made of the metal member, noise and vibration are increased. Since noise and vibration due to sliding of the bearing and rolling of balls in the bearing can be avoided, noise and vibration of the entire electronic device can be significantly reduced.

Since the bearing portion is formed integrally with a part of the frame, the number of components of the stepping motor is small, and the number of assembling steps for connecting the bearing portion and the frame is unnecessary. Therefore, the stepping motor is inexpensive. Can be manufactured.

Since the sphere is arranged between the bearing and the rotary shaft, for example, when a sphere having a smooth surface is used, the sliding noise between the bearing and the sphere can be reduced, Noise and vibration of the entire electronic device can be reduced.

Since the radial and axial loads by the rotary shaft or the sphere are supported by the same portion of the bearing, the rotary shaft does not rattle in either the axial direction or the radial direction. Noise caused by rattling of the shaft in the radial direction
Since the vibration is eliminated, the noise and vibration of the entire electronic device can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a bearing structure of a stepping motor according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a bearing structure of a stepping motor according to a second embodiment of the present invention.

FIG. 3 is a vertical sectional view of a bearing structure of a stepping motor according to a third embodiment of the present invention.

FIG. 4 is a vertical sectional view of a bearing structure for a stepping motor according to a fourth embodiment of the present invention.

FIG. 5 is a vertical sectional view of a bearing structure of a stepping motor according to a fifth embodiment of the present invention.

FIG. 6 is a vertical sectional view of a bearing structure of a stepping motor according to a sixth embodiment of the present invention.

FIG. 7: Bearing structure of conventional stepping motor and VT
FIG.

[Explanation of symbols]

 1 Bearing structure of stepping motor 2 Stepping motor 3 Bearing part 4 Frame 5 Rotating shaft 10 Ball

Claims (4)

[Claims] 1. A bearing structure for a stepping motor, comprising at least a frame provided with a bearing and a stepping motor having a rotary shaft engaging with the bearing, wherein the bearing is made of a resin member. Bearing structure for stepping motors. 2. The bearing structure for a stepping motor according to claim 1, wherein the frame is made of a resin member, and a bearing portion is integrally formed on a part of the frame. 3. The bearing structure for a stepping motor according to claim 1, wherein a sphere is arranged between the bearing portion and the rotary shaft. 4. The radial or axial load of the rotary shaft or the sphere is supported by the same portion of the bearing portion, or claim 2, or claim 3. Bearing structure for stepping motors.