JPH0526330A - Backlash eliminating device - Google Patents

Abstract

PURPOSE:To eliminate backlash by adjusting a distance between axles automatically, even when variations of eccentricity or thickness of gear teeth or the like are generated in a worm gear and a worm wheel. CONSTITUTION:A worm gear 2 is rotated around a rotating attaching portion 3 of a fulcrum of a worm chassis 4, and always pressed onto a worm wheel 1 with an elastic force of a spring 5, thereby even when variations of eccentricity or thickness of gear teeth or the like are generated in the worm wheel 1 and the worm gear 2, a distance between axles can be adjusted automatically by the elastic force of the spring 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlash removing device used in a power transmission device using a worm gear.

[0002]

2. Description of the Related Art Conventionally, in a worm gear transmission device, a chassis supporting a worm gear is fixed to a base.
In this case, the axial distance between the worm gear and the worm wheel is fixed.

[0003]

Therefore, backlash may increase during use due to eccentricity of the worm gear or worm wheel, variations in tooth thickness, etc., and the output shaft may rattle, and the backlash may decrease. As a result, the gears bite into each other and the power motor is overloaded, so that there is a drawback in that more than necessary power performance is required.

The present invention is intended to solve the above-mentioned problems. Even if the eccentricity or tooth thickness of the worm gear or worm wheel changes, the axial distance can be automatically adjusted to eliminate the backlash. An object is to provide an excellent backlash removing device.

[0005]

In order to achieve the above object, a backlash removing device of the present invention includes a worm wheel attached to a rotating shaft, a worm gear meshing with the worm wheel, and a worm gear supporting the worm wheel. A movable chassis that has a rotation mounting part that serves as a rotation fulcrum on the tangent line of the meshing pitch circle, an elastic member whose one end is attached to the movable chassis so that the worm gear is pressed against the worm wheel, and the movable chassis rotates to rotate. And a mounting base for mounting the mounting portion and fixing the other end of the elastic member.

[0006]

Therefore, according to the backlash removing device of the present invention, the worm gear rotates about the rotary mounting portion of the fulcrum of the movable chassis and is constantly pressed against the worm wheel side by the elastic force of the elastic member. For,
Even if the worm gear, the worm wheel, or the like changes in eccentricity or tooth thickness, the axial force is automatically adjusted by the elastic force of the elastic member, and the backlash can be removed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the backlash removing device of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the configuration of the embodiment. In FIG. 1, the worm gear 2 has bearings 9a, 9b, 9
It is incorporated in the worm chassis 4 via c and 9d. The worm wheel 1 (here, a helical gear because it is a resin-molded gear) is rotatably mounted on a rotary shaft 10, and the rotary shaft 10 serves as an output end. A worm gear 2 is supported on the worm chassis 4, and the tangent line of the meshing pitch circle of the worm wheel 1 that is parallel to the center line of the worm gear 2 intersects with the center line of the tooth width of the middle gear 7 rotated by the drive motor 8. A rotary mounting portion 3 serving as a rotation fulcrum is provided on the surface of the mounting base 6 so that the mounting base 6 can rotate like a pendulum.

On the opposite side, a coil spring 5 for pressing the worm gear 2 against the worm wheel 1 is arranged. The spring 5 has an elastic force that repels the reaction force that the worm gear 2 receives from the worm wheel 1 during power transmission and presses it against the worm wheel 1.

The worm chassis 4 is provided with four elongated holes 11. When the elongated hole 11 is fastened to the mounting base 6 with a stepped screw (not shown), the worm chassis 4 is opened so that the worm chassis 4 can rotate in the arrow directions V and W around the rotary mounting portion 3. The length of the long hole is such that the worm gear 2 and the worm wheel 1 are not disengaged even if the worm chassis 4 is rotated counterclockwise due to an overload applied to the rotary shaft 10.

Next, the operation of the above configuration will be described. Since the worm gear 2 and the worm wheel 1 have variations due to eccentricity and tooth thickness, the optimum axial distance changes due to rotation. In this case, the elastic force of the spring 5 causes the worm chassis 4 to rotate about the rotary mounting portion 3 and the worm gear 2 to follow so that the optimum axial distance is achieved. The force acting on the worm gear 2 generated by the rotation changes at the time of rotation as shown by the arrow in FIG. 2, but the component is divided into a force perpendicular to the worm axis and a force parallel to the worm axis. It is pressed against the worm wheel 1 side by the elastic force of the worm wheel 1. In the latter, the rotary mounting portion 3 is on the tangent line of the mesh pitch circle of the worm wheel 1,
It can be held without generating a rotational force centering on.

As described above, according to the above-described embodiment, the worm gear 2 is moved to the worm wheel 1 side by the elastic force of the spring 5 even if the eccentricity of each gear, the tooth thickness, and the temperature change the optimum inter-axis distance. Since it is pressed against, backlash can always be removed. Further, since the worm wheel 1 and the worm gear 2 do not bite into each other, the power motor 8 having the minimum necessary drive performance can be used.

[0013]

As is apparent from the above description, in the backlash removing device of the present invention, the worm gear rotates about the rotary mounting portion of the fulcrum of the movable chassis and is constantly pushed toward the worm wheel by the elastic force of the elastic member. Even if eccentricity or tooth thickness changes occur in the worm gear, worm wheel, etc., the elastic force of the elastic member automatically adjusts the axial distance to eliminate backlash. It has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of an embodiment of a backlash removing device of the present invention.

FIG. 2 is a plan view for explaining a force acting on a worm gear generated during rotation in the operation of the embodiment.

[Explanation of symbols]

 1 Worm Wheel 2 Worm Gear 3 Rotating Mounting Part 4 Worm Chassis 5 Spring 6 Mounting Base 7 Middle Gear 11 Slotted Hole

Claims (1)

Claims: 1. A worm wheel mounted on a rotary shaft, a worm gear meshing with the worm wheel, a worm gear supported, and a rotation fulcrum on a tangent line of a meshing pitch circle of the worm wheel. A movable chassis having a rotary mounting portion, an elastic member having one end attached to the movable chassis so as to press the worm gear against the worm wheel, and a rotary mounting portion for rotating the movable chassis. A backlash removing device having a mounting base for fixing the other end of the member.