JPH1068995A - Worm gear backlash removing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the backlash of a worm gear mechanism, without any adjustment by extending the parallel spring of a parallel spring mechanism, in parallel with the shaft of a worm and attaining fixation for generating force for pressing the worm on a worm wheel, so as to obtain deflections. SOLUTION: Ball bearings 10 and 11 are incorporated in a motor frame 12 and positioned in a thrust direction by a pressure spring 13. A motor bracket 14 is fitted to the motor frame 12 and leaf springs 15 and 16 having the same dimension are attached to the motor bracket 14, in parallel with a motor shaft 9. The leaf springs 15 and 16 are attached to a leaf spring holder 17 whose attaching part has the same dimension and the leaf spring holder 17 is fixed on a base. This holder 17 is fitted to generate the force for pressing the worm 7 on the worm wheel 1, so that the deflections are generated in the leaf springs 15 and 16. Thus, the backlash of the worm gear mechanism can be effectively removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlash removing mechanism of a worm gear mechanism used for a remote control camera platform equipped with a television camera.

[0002]

2. Description of the Related Art Conventionally, a remote control camera pan head equipped with a television camera has a pan rotation mechanism that rotates in a horizontal plane and a tilt rotation mechanism that rotates in a vertical plane. Worm gear mechanisms have been used for the following reasons. The first reason is that the rotational torque of the drive motor is increased by the television camera unit instead of decreasing the speed, and is reliably rotated as instructed. The second reason is that rotation from the drive motor is transmitted to the camera, but due to the weight imbalance of the camera,
This is for self-braking the force of the camera to rotate.

In the worm gear mechanism, there is a backlash between the teeth. Conventionally, assembly adjustment has been generally performed to reduce the backlash.

[0004]

The above-mentioned prior art includes the following:
There is a drawback that the smaller the backlash is, the more difficult it is to adjust, and even if it is adjusted once, the backlash increases with the use time. When the backlash increases, there arises a problem that the screen is displaced when the camera is positioned and a positioning angle error increases.

It is an object of the present invention to eliminate these disadvantages and to provide a method for eliminating backlash of a worm gear mechanism without adjustment.

[0006]

According to the present invention, in order to attain the above object, the distance between the axes of the worm and the worm wheel is kept short and constant by pressing the worm against the worm wheel at a constant pressure. Even if the worm wheel or worm is worn, backlash is prevented from occurring.

As a method of pressing the worm against the worm wheel, a bearing holder for holding the worm bearing is held by a parallel spring extending parallel to the worm shaft, and a force for pressing the worm against the worm wheel is generated by the parallel spring. In this case, the bending is generated and fixed to the base.

As a result, the worm is supported by the worm bearing so as to be free in the rotational direction but not to move in the axial direction of the worm. The worm bearing is supported by a parallel spring via a worm bearing holder. In the direction, the worm is held with high rigidity and the worm is pressed against the worm wheel with a constant force, so the worm is positioned against the worm wheel without backlash, so there is no backlash of the worm gear mechanism without adjustment You can do it.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The worm wheel 1 is supported by a worm wheel bearing 2, and the worm wheel bearing 2 is mounted on a worm wheel bearing holder 3, and the worm wheel bearing holder 3 is fixed to a base 4. The worm wheel 1 is connected to a television camera 6 via a camera rotation axis 5.

On the other hand, a worm 7 meshes with the worm wheel 1 to form a worm gear mechanism. The worm 7 is fixed to a motor shaft 9 of a motor 8.
The motor shaft 9 is rotatably guided by ball bearings 10 and 11. The ball bearings 10 and 11 are incorporated in a motor frame 12 and are positioned by a preload spring 13 in a thrust direction. A motor bracket 14 is attached to the motor frame 12, and the motor bracket 1
4, two leaf springs 15, 16 of the same size are attached in parallel to the motor shaft 9. The leaf springs 15 and 16 are attached to a leaf spring holder 17 having the same dimensions of the leaf spring attachment portion, and the leaf spring holder 17 is fixed to the base 4. The leaf spring holder 17 is attached to the leaf springs 15 and 16 so as to generate an exaggerated bending as shown in FIG. 1 so that a force for pressing the worm against the worm wheel 1 is generated.

In this operation, when the motor rotates according to a command from a control unit (not shown), the rotation is transmitted to the worm 7 via the motor shaft 9 and the worm 7 rotates. Then, the worm wheel 1 meshing with the worm 7 rotates. At this time, the worm 7 is pressed against the worm wheel 1 by the parallel spring composed of the leaf springs 15 and 16, and the parallel spring composed of the leaf springs 15 and 16 Has high rigidity in the axial direction of the worm, and presses the worm 7 exactly in the normal direction of the worm wheel 1.

Therefore, the backlash of the worm gear mechanism can be completely removed, and even if the worm wheel and the worm are worn, the worm is pressed against the worm wheel in accordance with the wear, so that the backlash can be removed even in this case.

Therefore, the rotation of the motor is accurately transmitted to the worm wheel, and the television camera 6 can be quietly and accurately positioned without backlash or backlash.

Further, at the time of manufacture, an appropriate worm pressing force can be obtained just by visually checking the deflection of the leaf spring, and particularly, delicate assembly is not required and troublesome backlash adjustment is not required.

In this embodiment, an example in which the present invention is applied to a remote control camera head of a television camera has been described.

[0016]

As described above, according to the present invention, the backlash of the worm gear mechanism can be effectively eliminated, the angular positioning accuracy can be improved, and high-precision positioning without backlash even when the worm gear mechanism is worn can be achieved. It is possible to achieve quiet operation since noise due to backlash due to backlash is also eliminated.

Further, since assembly and adjustment are easy, there is also an effect that the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention.

FIG. 2 is a side view of one embodiment of the present invention.

[Explanation of symbols]

1: worm wheel, 7: worm, 10, 11: ball bearing, 13: preload spring, 15, 16: leaf spring.

Claims (2)

[Claims] 1. A worm wheel, a worm wheel bearing that supports the worm wheel, a base to which the worm wheel bearing is coupled, a worm that meshes with the worm wheel, and a worm that rotatably supports the worm wheel. And a worm bearing for positioning so as not to move in the axial direction of the worm, a worm bearing holder for holding the worm bearing, and a parallel end having one end fixed to the worm bearing holder and the other end coupled to the base. A spring mechanism, and the parallel spring of the parallel spring mechanism is fixed so as to extend parallel to the axis of the worm, and to bend so as to generate a force for pressing the worm against the worm wheel. Features a worm gear backlash removal mechanism. 2. The worm gear backlash removing mechanism according to claim 1, wherein the worm bearing is a bearing of a worm drive motor.