JPS5845619B2 - Dust prevention device for floating internal gear set - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dust prevention device for a power transmission mechanism having an automatic tension adjustment function for a transmission band such as a belt or chain including a set of internal gears. is an internal gear in a transmission mechanism in which an internal gear is meshed with an external small gear in a floating state without a shaft, and the internal gear is eccentric by an arbitrary amount to apply tension to the transmission band of a belt or chain. This invention relates to a dust prevention device for the meshing part of a gear set.

There is a gap between the internal gear and the external pinion of the internal gear set that mesh in a floating state as described above, but dust and other foreign matter may enter from the outside into this gap, or rainwater may enter the gap. If they penetrate, there are problems such as damage to the teeth and increased wear on the teeth.

The present invention was made to solve these problems, and by providing a bellows between the side surface of the internal gear and the external pinion to isolate the gap in the floating internal gear set from the outside. , prevents foreign objects and rainwater from entering the meshing area, protects lubricants such as grease applied to the meshing area for a long period of time, minimizes wear on tooth surfaces, and prevents tooth damage caused by biting foreign objects. The purpose of this is to stabilize the meshing of the internal gear set.

The present invention will be described in detail below based on the drawings.

In the figure, 1 is a driving wheel, 2 is a driven wheel, 2a is an internal tooth formed on its inner circumference, 3 is an external small gear that internally meshes with the internal gear 2, and 4 is a driving wheel 1 and a driven wheel. A toothed belt is a transmission band extending around the outer circumference of an internal gear 2, which is a driving wheel.
is designed to maintain appropriate tension at all times.

In the present invention, a hollow disc-shaped guide plate 5 is fastened and fixed to both sides of an internal gear 20, which is a driven vehicle, with bolts 6 and nuts 7, and a bellows 8 is fitted to the shaft portion 3a of the external pinion gear 3. The boss portion 8a is fixed to the shaft portion 3a as shown in FIG.

FIG. 4 shows another embodiment of the present invention, in which an ear edge 5a is formed on the inner circumference of the guide plate 5, and an annular protrusion 8c protruding inside the outer circumference 8b of the bellows 8 is formed on the inner circumference of the guide plate 5. The bellows 8 is fitted into the annular groove of the edge 5a and locked, and the boss portion 8a of the bellows 8 is slidably fitted onto the shaft portion 3a of the external small gear 3.

Next, the effects of the apparatus of the present invention constructed as described above will be explained.

The internal gear 2, which is a driven wheel driven by the drive wheel 1 and the toothed belt 4, has no shaft (the internal gear 2 is internally meshed with the external small gear 3 in a floating state). Therefore, the rotation center of the internal gear 2 is eccentric to the rotation center of the external pinion gear 3, and the rotation center of the internal gear 2 rotates around the rotation center of the external pinion gear 3.

For this reason, there is a gap between the internal gear 2 and the external small gear 3, but according to the present invention, the gap is blocked from the outside by the flexible bellows 8 that allows eccentric movement. It is possible to prevent foreign matter and rainwater from entering the meshing portion of the internal gear set, reduce tooth damage and wear, and significantly improve the durability of the internal gear set.

The present invention relates to an internal gear set, and since the internal gear 2 and the external pinion 3 rotate in the same direction, the outer circumference 8b of the bellows 8 and the guide plate 5 in the embodiment shown in FIG. Although the sliding speed is not very large, the maximum sliding speed occurs on the opposite side of the meshing pitch point.

Therefore, as in the embodiment shown in FIG. This is advantageous because the sliding rotation radius becomes smaller and the sliding speed also becomes smaller.

In the above embodiment of the present invention, the external pinion gear 3 is used as the final drive side, but the effect is the same even when the external pinion gear 3 is used as the driving side.

[Brief explanation of the drawing]

FIG. 1 is a front view of a transmission mechanism having an automatic tension adjustment function, FIG. A view along arrow A in the figure and FIG. 4 are cross-sectional views of essential parts showing an embodiment of the present invention. 1... Drive wheel, 2... Driven wheel (internal gear), 2a... Internal gear, 3... External pinion gear, 3a. ...Shaft, 4...Toothed belt, 5...Guide plate, 5a...Ear edge, 6
...Bolt, 7...Natsuto, 8...
--Bellows, 8a...Boss part, 8b...
. . . Outer periphery, 8c --- Annular protrusion.

Claims (1)

[Claims] 1. A transmission band is passed between the driving wheel and the driven wheel, internal teeth are formed on the inner circumference of either the driving wheel or the driven wheel, and this internal gear meshes with the external pinion gear in a floating state. In the transmission mechanism that automatically adjusts the tension of the transmission band, a bellows is provided between the side surface of the internal gear and the external small gear to isolate the air gap of the floating internal gear set from the outside. A dust-proof device with a floating internal gear set.