JPH099604A - Bearing device for stepping motor - Google Patents

Abstract

PURPOSE: To provide a bearing device, for a stepping motor, by which a load resistance acting on an output shaft in the rotation of the output shaft is made small as far as possible, which can obtain a stable characteristic, which can be centered precisely and surely, which can reduce a vibration noise as far as possible and which can suppress component costs and production costs from being increased as far as possible. CONSTITUTION: A bearing device is provided with a pivot bearing 16 by which the tip part 12A of an output shaft 12 for a stepping motor 1 is supported so as to be freely rotatable via a ball 14. A recessed part 16a which receives the ball 14 at the pivot bearing 16 is formed to be a conical shape, and the vertical angle θ of the recessed part 16a is set at 141 deg. to 150 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device attached to a stepping motor used for precisely driving a movable part in electronic equipment such as a video camera, and more particularly to a bearing device having a spiral groove formed therein. And a pivot bearing that rotatably supports the tip of an output shaft (screw shaft or the like) via a ball.

[0002]

2. Description of the Related Art As a bearing device for a stepping motor of this type, as shown in FIG. 3, a tip portion 12A of an output shaft (screw shaft or the like) 12 having a spiral groove or the like in a stepping motor is attached to a steel ball or the like. Ball consisting of 1
There is known one provided with a pivot bearing 16 which is rotatably supported via the bearing 4.

The tip portion 12A of the output shaft 12 is formed with a conical or spherical recess 12a for receiving the ball 14, and the pivot bearing 16 is provided with a conical recess 16a for receiving the ball 14. Are formed.

The output shaft 12 is formed by a spring in the body of a stepping motor (not shown).
The pivot bearing 16 receives both thrust load and radial load from the output shaft 12 via the ball 14 because it is biased in a direction to push the 2A outward.

[0005]

In the bearing device for the stepping motor as described above, (1) to obtain stable characteristics by reducing load resistance acting on the output shaft as much as possible during rotation of the output shaft, ( 2) Accurate and reliable centering to reduce vibration noise as much as possible,
(3) Although it is desired to suppress the increase in the component cost and the manufacturing cost for achieving the above (1) and (2) as much as possible, it is said that such a request is still sufficiently achieved. Hard to say.

The present invention has been made to achieve the above-mentioned demands, and an object of the present invention is to reduce the load resistance acting on the output shaft as much as possible during rotation of the output shaft to obtain stable characteristics. In addition to being able to obtain it, it is possible to perform centering accurately and surely to reduce vibration noise as much as possible, and further, it is possible to suppress increase in parts cost and manufacturing cost as much as possible. An object of the present invention is to provide a bearing device for a stepping motor.

[0007]

In order to achieve the above-mentioned object, a bearing device for a stepping motor according to the present invention comprises a pivot bearing for rotatably supporting a tip end portion of an output shaft of the stepping motor via a ball. The recess for receiving the ball in the pivot bearing has a conical shape, and the apex angle of the recess is 141 degrees or more.

[0008]

In the bearing device of the stepping motor according to the present invention having the above-described structure, as shown in FIG. 2B, the conical recess 16a in the pivot bearing is used.
Since the apex angle θ ′ of is 14 degrees or more, preferably 141 degrees to 150 degrees, the diameter d of the portion of the ball 14 that is in pressure contact with the recess 16a is relatively small.

On the other hand, the apex angle θ of the conical recess 16A in the conventional pivot bearing 16 shown in FIG.
Since it is 140 degrees or less, and normally 80 to 120 degrees is desirable, the diameter D of the portion of the ball 14 that is in pressure contact with the recess 16a is the same as that of the present invention, as shown in FIG. 2 (A). It will be bigger than the one.

Here, when a trial experiment was actually conducted with the apex angle of the conical recess in the pivot bearing being 141 degrees or more, stable and good characteristics were obtained as compared with the conventional one, and moreover, the conventional one was obtained. The centering can be performed almost exactly and surely as much as that of the ones, and the vibration noise can be reduced as much as possible, and further, the increase of the component cost and the manufacturing cost can be suppressed.

This is in accordance with the invention a ball 1
It is considered that this is because the diameter d of the portion of 4 which is pressed against the recess 16a is smaller than the diameter D of the conventional one, so that the load resistance acting on the output shaft 12 when it is rotated is reduced.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a bearing device for a stepping motor according to the present invention. In the stepping motor 1 shown in the figure, a radial slide bearing 6 is provided at the center of a main body 10 in which a 4-phase stator coil 2 is arranged along the inner circumference thereof, and a proximal end side of an output shaft 12 having a magnet 4 fitted therein. It is rotatably inserted while being supported by.

A support member 8 having a U-shaped cross section is fixed to the front end surface of the main body 10 with its opening facing upward.

A tip end side of the output shaft 12 located outside the main body portion 10 is a screw shaft having a spiral groove or the like, and the vertical side portion 8A on the side opposite to the main body portion 10 of the supporting member 8 is provided with the above-mentioned screw shaft. A pivot bearing 16 is provided that rotatably supports the tip portion 12A of the output shaft 12 via balls 14 made of steel balls or the like.

A spherical recess 12a for receiving the ball 14 in point contact is formed at the tip 12A of the output shaft 12, and a conical recess 16a for receiving the ball 14 is formed in the pivot bearing 16. Are formed.

The apex angle θ'of the conical recess 16a in the pivot bearing 16 is 141 degrees or more, preferably 141.
It is said to be between 150 and 150 degrees.

Since the output shaft 12 is biased in the main body 10 of the stepping motor 1 by the spring 9 in a direction to push the tip 12A outward, the pivot bearing 16 extends from the output shaft 12 to the ball 14 in the direction of the ball 14. Both the thrust load and the radial load will be received via.

In the stepping motor bearing device of the present embodiment having the above-described structure, as shown in FIG. 2B, the conical recess 16 in the pivot bearing is used.
Since the apex angle θ'of a is 141 degrees or more, preferably 141 degrees to 150 degrees, the concave portion 16a of the ball 14 is
The diameter d of the portion pressed into contact with is relatively small.

On the other hand, the apex angle θ of the conical recess 16A in the conventional pivot bearing 16 shown in FIG.
Since it is 140 degrees or less, and normally 80 to 120 degrees is desirable, the diameter D of the portion of the ball 14 that is in pressure contact with the recess 16a is the same as that of the present invention, as shown in FIG. 2 (A). It will be bigger than the one.

As described above, in the present embodiment, since the diameter d of the portion of the ball 14 that is in pressure contact with the recess 16a is smaller than the diameter D of the conventional one, the load acting on the output shaft 12 when it is rotated. The resistance decreases.

Therefore, stable and good characteristics can be obtained as compared with the conventional one, and moreover, the centering can be performed almost exactly and surely as much as the conventional one and the vibration noise can be reduced as much as possible. In addition, it is possible to suppress the increase of parts cost and manufacturing cost.

[0022]

As can be understood from the above description, according to the bearing device for a stepping motor of the present invention, the load resistance acting on the output shaft when it rotates can be made as small as possible and stable characteristics can be obtained. In addition to being able to obtain, it is possible to accurately and surely perform centering, reduce vibration noise as much as possible, and further, it is possible to suppress increase in component cost and manufacturing cost as much as possible. .

[Brief description of drawings]

1A and 1B show an embodiment of a bearing device for a stepping motor according to the present invention, in which FIG. 1A is an overall sectional view and FIG.
FIG.

FIG. 2 is a diagram which is used for describing an operation effect of an embodiment of a bearing device for a stepping motor according to the present invention.

FIG. 3 is a partially enlarged view showing a main part of an example of a conventional bearing device for a stepping motor.

[Explanation of symbols]

 1 Stepping Motor 10 Main Body 12 Output Shaft 12A Tip 14 Ball 16 Pivot Bearing 16a Recess

Claims (1)

[Claims] 1. A stepping motor is provided with a pivot bearing that rotatably supports the tip end of the output shaft via a ball, and a concave portion for receiving the ball in the pivot bearing has a conical shape, and an apex angle of the concave portion is A bearing device for a stepping motor, which is set to 141 degrees or more.