JPH02248726A - Shaft braking device - Google Patents

Abstract

PURPOSE:To obtain optional braking torque and improve durability at a low production cost by rotatably fitting a guide centering a support shaft, and invariably pressing and exciting both sides of this support shaft to the rotary shaft side with elastic members. CONSTITUTION:A guide 11 having a guide groove 11a on the inner face is arranged on the upper side of a rotary shaft 10. Balls 12 are stored between the guide 11 and the rotary shaft 10. The guide 11 is rotatably fitted centering a support shaft 13. The upper section of the guide 11 is invariably pressed and excited to the rotary shaft 10 side by springs 14 and 15. The braking force applied to the rotary shaft 10 is mitigated by the springs 14 and 15. Optional braking torque can be obtained by changing the elastic coefficient of the springs in this way, and durability can be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a shaft braking device that can be used for a rotating shaft of equipment that requires shaft braking, and is particularly applicable to a shaft side movement mechanism of a display section of an electronic device. The present invention relates to a suitable device.

[Conventional technology]

Conventionally, most shaft braking devices of this type have a structure using a spring clutch. The spring clutch mechanism will be briefly described below.

FIGS. 2(a) and 2(b) are diagrams showing the structure of a spring clutch. A torsion spring 2 is wound around the rotating shaft l, and one end 2a of the torsion spring 2 is attached to a rotation prevention lip 3. It is locked to.

Here, when the rotating shaft l rotates in the direction of arrow A, it rotates in the opposite direction to the winding direction of the torsion spring 2 (the direction in which the torsion spring 2 opens), so the spring diameter increases and the rotating shaft 2 reduces frictional resistance. It will rotate without receiving it.

On the other hand, the rotation axis! When rotated in the direction of arrow B, the direction is the same as the winding direction of the torsion spring 2 (the direction in which the torsion spring 2 closes), the spring diameter becomes smaller, and the rotation axis l is locked.

However, in this case, if the torque exceeds a certain level, the rotating shaft l will slip and rotate.

(Problems to be Solved by the Invention) However, in the conventional example described above, since the structure utilizes the slip of the torsion spring 2, there are the following drawbacks.

(i) Since braking torque is applied directly to the N rotating shaft 1, the rotating shaft 1 needs to have a certain degree of strength (material, thickness).

(ii) The clearance between the inner diameter of the torsion spring 2 and the outer diameter of the rotary ring l is important, and as a result, the inner diameter tolerance of the torsion spring 2 becomes very tight (the lock starting torque changes greatly depending on the inner diameter tolerance of the torsion spring 2), and the torsion The manufacturing cost of the spring 2 increases significantly. (iii) Since the braking force is not very large, it is necessary to have a large number of such devices. (
iv.) It is necessary to apply grease to the joints.

On the other hand, FIGS. 3(a) and 3(b) are diagrams showing a conventional shaft braking device. 4 is a rotating shaft that requires braking, 5 is a ball (or cylinder), and 6 is a guide fixed to the main body of the device via screws 7.

In FIG. 3(a), when the rotating shaft 4 rotates in the X direction, the ball 5 follows the rotation of the rotating shaft 4 and rotates clockwise along the guide groove 68. However, at this time, the rotating shaft 4
Since the gap H between the ball 5 and the guide 6 is tapered, the ball 5
When the rotation shaft 4 rotates in the Y direction as shown in FIG. 3(b), the ball 5 moves counterclockwise along the guide groove 6a. rotate in the direction. At this time, since there is a sufficient gap H between the rotating shaft 4 and the guide 6, the ball 5 is not locked between the rotating shaft 4 and the guide 6, and therefore the rotating shaft 4 can rotate only in the Y direction.

However, in the shaft braking device described above, the guide 6 is fixed and braking torque is applied directly to the rotating shaft 4, so the rotating shaft 4 not only needs to have a certain degree of strength but also has durability. There was a problem with sexuality.

SUMMARY OF THE INVENTION An object of the present invention was made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide a shaft braking device that can obtain any desired braking torque, can be manufactured at low cost, and has excellent durability.

(Means for Solving the Problems) In order to achieve the above object, the present invention incorporates a rotating member in the gap between the guide having a groove on the inner surface and the rotating shaft, and applies a load to the rotation of the shaft. In a shaft braking device configured to apply torque, the guide is rotatably mounted around a support shaft, and both sides of the support shaft are always pressed toward the rotating shaft by elastic members.

[Effect]

As described above, according to the present invention, since the guide is configured to be biased by the elastic member, the braking force applied to the rotating shaft can be alleviated by the elastic member, thereby increasing the strength of the rotating shaft. This is no longer necessary, and the durability has also been improved. In addition, any braking torque can be obtained by changing the elastic constant of the elastic member, and since there are no parts that require high precision and the number of parts is small, manufacturing costs can be reduced.

〔Example〕

Hereinafter, details of the present invention will be described using examples shown in the figures.

FIGS. 1(a) to 1(c) are schematic configuration diagrams showing one embodiment of the shaft braking device according to the present invention.A guide 11 having a guide groove 11a on the inner surface is disposed on the upper side of the 0-rotation shaft lO. A rotating member, in this embodiment a ball 12, is housed in the gap H between the guide 11 and the rotating wheel lO. The gap H has the largest distance near the support shaft 13, and tapers as it moves away from there. The guide 11 is rotatably supported at its center by a support shaft 13, and the upper surface of the guide 11 is always urged toward the rotation axis 1O by a spring 14.15. There is. That is, the spring 14.15 is interposed between the bearing part 16 disposed around the guide 11 and the upper surface part of the guide 11. In this embodiment, the spring 14.15 is attached to the support shaft 13. The structure is such that they are placed at equal intervals to the left and right with the center at the center. Therefore, the guide 11 has a structure in which the upper surface portion of the guide 11 is urged toward the rotation axis 10 by the springs 14 and 15 at positions equally distant from the support shaft 13.

Now, in the above structure, the axis of rotation lO is as shown in Fig. 1 (
When rotating in the Y direction as shown in a), the ball 12 also rotates,
When the rotational tangential force causes the guide 11 to move to the left, the distance H between the rotating shaft 10 and the guide 11 is tapered, so that the left side of the guide 11 moves as shown in FIG. 1(c).
The ball 12 is pushed up in the downward direction shown in the figure, and eventually comes into contact with the wall 11b of the guide groove lla, and cannot move any further. Here, the guide 11 is provided with an F by a spring 14.
Spring pressure is applied in the opposite direction to prevent the ball 12 from rotating. This is the 0 rotation axis l which becomes the rotational braking force of the rotation axis IO.
The operation is similar to that described above when O rotates in the Y direction shown in FIG. 1(b).

In addition, by changing the spring constant of springs 14 and 15,
Shaft rotation load torque can be set freely.

In addition, if a large braking torque is required,
A cylindrical member may be used instead.

〔Effect of the invention〕

As explained above, the shaft braking device according to the present invention has a structure in which the guide is rotatably mounted around the support shaft, and both sides of the support shaft are constantly urged toward the rotating shaft by elastic members. Therefore, the braking force applied to the rotating shaft is alleviated by the elastic member, so there is no need to increase the strength of the rotating shaft as much as before, and the durability can also be improved. play.

In addition, any braking torque can be obtained by changing the elastic constant of the elastic member, and the device of the present invention does not require any parts that require high precision, and the number of parts can be reduced, so manufacturing costs can be reduced. It also has the effect of being inexpensive. Furthermore, when a large braking torque is required, the necessary braking torque can be easily obtained by using a cylindrical member as the rotating member built into the gap between the guide and the rotating shaft.

[Brief explanation of drawings]

FIGS. 1(a) to (c) are schematic configuration diagrams showing one embodiment of a shaft braking device according to the present invention, and FIGS. 2(a) and (b) are front and side views showing the structure of a spring clutch. , Figure 3(a),
(b) is a schematic configuration diagram showing an example of a conventional shaft braking device. lO rotating shaft, 11 guide, llal guide groove 2 ball, 13 support shaft, l 4, 15 spring.

Claims (1)

[Claims] A shaft braking device in which a rotating member is built into a gap between a guide having a guide groove on the inner surface and a rotating shaft, and is configured to apply load torque to rotation of the shaft, in which the guide is freely rotatable about the supporting shaft. What is claimed is: 1. A shaft braking device, characterized in that the shaft braking device is attached to the shaft and always presses both sides of the support shaft toward the rotating shaft by an elastic member.