JPS6132530B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gear that prevents meshing noise generated when the gears mesh.

Conventionally, plastic gears have been used for precision equipment such as watches and audio equipment, but since these gears are manufactured by injection molding, they may suffer from eccentricity or other distortions due to shrinkage during molding. It is unavoidable that this occurs, and therefore, it is unavoidable that meshing noise is generated due to dimensional inaccuracy.

In view of these points, it is an object of the present invention to provide a gear that does not generate meshing noise even if some dimensional inaccuracy occurs due to shrinkage during molding or the like.

The present invention provides a gear made of a highly elastic material, including a gear body, an L-shaped rod-shaped base protruding radially from the periphery of the body and in the direction of the rotation axis of the body, and a gear formed at the tip of the base. The teeth are configured such that the teeth move in the circumferential and radial directions as the base elastically deforms in the circumferential and radial directions during meshing.

In gear meshing, if we consider the gear to be a rigid body,
In order for the two opposing gear surfaces to continue to contact each other while rotating at a predetermined angular velocity ratio and neither sink into nor separate from each other, the minute velocity in the direction of the common normal of both tooth surfaces at the point of contact must always be Must be equal. In other words, the tooth profile is designed such that at that moment there is no relative movement of the gears in the direction of the common normal, and the only relative movement is mutual sliding along the tangential plane at the point of contact. Therefore, if there is eccentricity or tooth pitch error in the gears, the tooth surfaces will not contact each other at the predetermined positions, resulting in interference between the teeth or misalignment of the tooth meshing timing. Become. When a misalignment occurs in the meshing timing, the number of meshing pairs of teeth changes, resulting in load fluctuations on the meshing part.Also, when tooth interference occurs, load fluctuations on the meshing part are also caused. This rapid fluctuation causes vibration and noise.

However, as in the present invention, when the tooth portions are elastically deformed during meshing, when tooth interference occurs, the tooth surfaces retreat in response to the increased load on this portion, canceling out the interference. Since the variation in the number of meshing pairs is canceled out according to the increase or decrease in the load on the meshing portion, there is no sudden variation in the load, and therefore no noise is generated.

Hereinafter, the present invention will be explained with reference to drawings of embodiments. In FIG. 1, reference numeral 1 denotes the main body of the spur gear, and the teeth 2 around it are continuous with the main body 1 through a base 3. The base 3 is formed thin and consists of a vertical arm 31 and a horizontal arm 32 formed in an L shape so as to protrude perpendicularly to the surface of the main body 1. When force is applied to the tooth surface 4, the base 3 is elastically deformed and the gear 2 is moved backward.

In this gear meshing state, as shown in FIGS. 2 and 3, the gear of the present invention meshing with the corresponding gear 50 contacts at point 5 of the tooth surface 4, and due to changes in the pitch of the tooth portion, etc. When the force applied to the contact point 5 fluctuates, the base 3 deforms elastically in accordance with the amount of the fluctuation, and as a result, the tooth 2 retreats as shown by the two-dot chain line, thereby acting to cancel out the fluctuation. do. This eliminates sudden changes in the load on each tooth, resulting in very quiet meshing. This elastic deformation of the base 3 is achieved by moving the toothed part 2 in the circumferential direction (in the direction of arrow C) by bending the horizontal arm 32 and the vertical arm 31, and also by twisting the horizontal arm 32 to some extent. cormorant. Further, the tooth portion 2 moves vertically (in the direction of arrow A) due to the deflection of the horizontal arm 32 and the vertical arm 31
Since it is possible to move in the radial direction (in the direction of arrow B) due to the deflection of This is absorbed through deformation to maintain quiet engagement. In this way, the tooth portion 2 moves three-dimensionally to absorb variations in load due to deformation of the gear, so tolerance for errors during gear manufacturing can be increased, and manufacturing is therefore facilitated. It is possible to reduce manufacturing costs. In addition, since the tolerance for dimensional errors is large, there is no problem of the gear rotation stopping when used at low torque due to the loss of buckle due to the out-of-roundness of the gear, which is the case with conventional products. Even in this case, the rotation is smoothly transmitted by the movement of the tooth portion 2.

Note that the strength of the elasticity of the base 3 needs to be set to an appropriate size depending on the magnitude of the rotational force to be transmitted.
13 curvature size, horizontal arm 32, vertical arm 3
It may be set as appropriate depending on the thickness, shape, etc. of 1.
Further, the base 3 may be provided with a vertical arm 31 relative to the main body 1, as shown by the two-dot chain line in FIG. 4, and the horizontal arm 32 and the tooth portion 2 may be formed at the tip of the vertical arm 31. Further, the gear of the present invention may be used on either the driving side or the driven side, or the gear of the present invention may be used for a corresponding gear.

5 and 6 show another embodiment of the present invention, in which a vertical arm 3 is provided around the crown gear body 10.
1. A vertical tooth portion 20 is provided via an L-shaped base portion 3 consisting of a horizontal arm 32. In this case as well, the tooth portion 20 can be moved three-dimensionally in the directions of arrows A, B, and C by the bending and twisting of the horizontal arm 32 and the vertical arm 31, and therefore the effect is completely the same as in the above case. It's the same.

When the gears mentioned above are made of urethane-based resin, excellent effects in terms of elasticity etc. can be achieved, but other resins may be used as long as they have excellent wear resistance and mechanical strength, or phosphor bronze or other resins may be used. Steel plates can also be used.

As explained above, the present invention makes the base of the tooth of the gear L-shaped so that it can be elastically deformed, and the teeth move back according to the fluctuation of the load during meshing, thereby absorbing sudden fluctuations in the load. In addition, the tooth portion is moved three-dimensionally to increase the tolerance for dimensional errors of the gear. Therefore, meshing noise can be significantly reduced even in gears with somewhat inaccurate dimensions, and is extremely useful especially when used in precision instruments such as watches where meshing noise is a problem.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention, FIG. 2 is a partial plan view of the engaged state, FIG. 3 is a front view thereof, FIG. 4 is a central sectional view, and FIG. 5 is a diagram of the present invention. FIG. 6 is a partially cutaway perspective view showing another embodiment of the present invention, and FIG. 6 is a central sectional view thereof. 1, 10... Gear body, 2, 20... Teeth, 3
... Base, 4 ... Tooth surface, 31 ... Vertical arm, 32 ...
...horizontal arm.

Claims (1)

[Claims] 1. A gear made of a highly elastic material, including a gear body, an L-shaped rod-shaped base protruding radially from the periphery of the body and in the direction of the rotation axis of the body;
The tooth is formed at the tip of the base, and the base is elastically deformed in the circumferential and radial directions during meshing, so that the teeth move in the circumferential and radial directions. Characteristic gears.