JPH09107671A - Stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepping motor in which a noise and a vibration due to the sliding operation of a shaft with a bearing part are small, in which a noise and a vibration are small when the vibration of the shaft is transmitted to an electronic apparatus via a frame and which is low-cost. SOLUTION: A bearing part 3 which is coupled to a shaft 5 is formed of a resin member. The load in the radial direction and the axial direction of the shaft is supported in the same part of the bearing part 3. A noise and a vibration are prevented when the shaft is slid with a bearing or when balls inside the bearing are rolled.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A stepping motor for a VTR camera will be described as an example of electronic equipment 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 is a stepping motor 2
And a frame 4 provided with a pivot bearing 11.

The rotating 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 And 9 are rotatably engaged with each other.

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.

Characteristics required for a VTR camera include 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. Needless to say, low noise and low vibration are also required for stepping motors for VTR cameras.

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 is hardly a problem 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 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 from the pivot bearing to the frame. It became noise and vibration transmitted to the VTR camera.

[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 stepping motor bearing structure with less noise and vibration.

[0014]

The stepping motor of the present invention is 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, the stepping motor comprising: The bearing portion is made of a resin member, and the radial and axial loads of the rotary shaft are supported by the same portion of the bearing portion.

Further, the frame is made of a resin member, and a bearing portion is integrally formed on a part of the frame.

A sphere is arranged between the bearing portion and the rotary shaft.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bearing structure for 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 stepping motor bearing structure 1 has a frame 4 provided with a stepping motor 2 and a bearing portion 3 formed of a resin member.

The rotary 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, and the bottom of the hole holds the axial load of the rotary shaft on the 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) 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 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. 6 is a table comparing noise and vibration magnitudes other than those of stepping motors.

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

There are three levels of noise / vibration other than the stepping motor of electronic equipment: large / medium / small. The noise / vibration of the stepping motor has a large conventional structure / the structure of the present invention is small. There are two levels.

[0028]

[Table 1]

It is clear from Table 1 that the noise / vibration of the entire electronic device incorporating the stepping motor cannot be reduced unless both the noise / vibration of the stepping motor and the noise / vibration of the 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 stepping motor having the conventional structure.

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

Especially when the noise and vibration other than those of 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 according to the present invention is capable of reducing noise and vibration of electronic equipment as compared with the conventional structure.

Moreover, the bearing portion 3 made of a resin member has a simple structure and can be manufactured at low cost. Therefore, 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 sphere 10 is arranged between the bearing portion 3 and the tip portion 5b of the rotary shaft. Descriptions other than those are omitted.

A recess is formed at the tip 5b of the rotary 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 make the surface of the spherical portion of the tip end smooth. 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 part that slides by applying an axial load to the bearing part can be easily made smooth and noise and vibration can be reduced. The sphere is a general-purpose small bearing sphere, which 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 is 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 in the radial direction by the amount of the gap 8. 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 due to radial rattling of the rotary shaft.

The bearing hole 3b 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, the structure other than the bearing portion is the same as that of the fourth embodiment, and therefore the description of the portion other than the bearing portion is omitted.

The bearing portion 3 has an inclined surface 3d which engages with the tip portion 5a of the rotary shaft 5 and the ball 10. The tip 5a and the ball 10 of the rotary shaft, which are pushed by the bearing 6 by the spring 6, hit the slope 3d and are supported in the axial direction and the radial direction of the rotary shaft. There is no rattling. Therefore, noise caused by radial rattling of the rotating shaft
Vibration can be eliminated.

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

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

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

A beveled surface is formed at the tip 5c of the rotary shaft 5, and the tip 5c of the rotary shaft pushed by the spring 6 onto the bearing portion 3 has a corner of the hole 3b at the bottom of the hole 3a of the bearing portion 3. 3c
It is supported in the axial and radial directions of the rotary shaft.

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

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.

[0057]

The bearing structure of the stepping motor according to the present invention has the following remarkable effects. Since the bearing part is made of a resin member, compared with the bearing structure of the conventional stepping motor in which the bearing part is made of a metal member, noise and vibration are large, compared to the rotating shaft and the bearing structure. Since noise and vibration due to sliding and rolling of balls in the bearing can be avoided, noise and vibration of the entire electronic device can be significantly reduced. Further, since the radial direction and the axial load of the rotary shaft are supported by the same portion of the bearing, the rotary shaft does not rattle in the axial direction or the radial direction. Noise and vibration due to rattling are eliminated, and the noise and vibration of the entire electronic device can be 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. Can be manufactured.

Since the sphere is arranged between the bearing portion 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.

[Brief description of the 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 of 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 3a hole 3b hole 4 Frame 5 Rotating shaft 5a Rotating shaft tip 6 Spring 7 Groove 8 Gap 9 Metal bearing 10 Ball

Claims (3)

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