JPS6347319Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a V-belt automatic transmission mechanism used in a motorcycle, and particularly relates to an improvement of a driven pulley in this automatic transmission mechanism.

The V-belt automatic transmission mechanism consists of a pair of drive and driven pulleys each having a V-shaped groove in cross section, and a V-belt wound between the pair of drive and driven pulleys.
The gear ratio is obtained by varying the groove width of each of the pulleys using centrifugal force or the like, thereby relatively varying the winding diameter of each pulley around which the V-belt is wound.

FIG. 1 is a partially cutaway sectional view of a main part showing a driven pulley 1 of the above-mentioned V-belt transmission mechanism (hereinafter simply referred to as transmission mechanism).

This driven pulley 1 includes a first pulley plate 3 that is rotatably supported on a shaft 2, and a cam (to be described later) that is also rotatably supported on the shaft 2 and that is mounted along the axial direction of the shaft 2. a second pulley plate 5 that can be moved by a predetermined width by a mechanism 4, and the first and second pulleys 3, 5
A V-belt 6 is wound between them. The first and second pulley plates 3, 5 are shown in FIG.
As shown in FIG. 2 in section AA, the boss portion 9a of the plate 9 is rotatably supported on the shaft 2 and has the clutch shoe 8 of the centrifugal clutch 7 disposed at one end.
, the first pulley plate 3 has a spline 9'
Since the second pulley plate 5 is respectively locked by the cam mechanism 4, the first and second pulley plates 3, 5 and the plate 9 rotate together.

By the way, the second pulley plate 5 mentioned above
is pressed in the thrust direction by a coil spring 10 disposed between the second pulley plate 5 and plate 9, and always works to narrow the groove width S of the driven pulley 1. Further, the cam mechanism 4 that locks the second pulley plate 5 to the boss portion 9a of the plate 9 and moves it by a predetermined width along the axial direction of the shaft 2 is connected to the circumferential surface of the boss portion 5a of the second pulley plate 5. The cam mechanism 4 (generally known as a torque sensor cam) consists of a crescent-shaped cam slot 5b formed in the cam slot 5b, and a pin 11 that is implanted on the circumferential surface of the boss portion 9a of the plate 9 and is inserted into the cam slot 5b. V acting on the second pulley plate 5 depending on the load on the shaft 2
The torque of the belt 6 is converted into a thrust force, and the second pulley plate 5 is moved in the thrust direction of the shaft 2 to change the winding diameter l of the driven pulley 1. 1 and 2, reference numeral 12 is a clutch housing of the centrifugal clutch 7, and this clutch housing 12 is fitted onto the shaft 2 through a spline 13 and fixed to the shaft 2 through a screw 14. . Further, reference numeral 15 denotes a bearing portion of the shaft 2 formed in a part of the housing housing the transmission mechanism.

By the way, the conventional driven pulley 1 mentioned above
Accordingly, since the second pulley plate 5 is directly connected to the plate 9 of the centrifugal clutch 7 via the cam mechanism, the torque fluctuation according to the load on the shaft 2 is directly connected to the second pulley plate 5 via the cam mechanism 4. It is transmitted to the plate 5 and moves the pulley plate 5 along the thrust direction of the shaft 2 (arrow B).

That is, according to the conventional driven pulley 1, since the second pulley plate 5 is directly moved in the thrust direction by the cam mechanism 4, the thrust force generated when moving in the thrust direction is directly applied to the V-belt 6. Therefore, when there is a sudden change in the load on the shaft 2 (for example, when approaching an uphill slope), a large thrust force due to the sudden change in rotational torque is transmitted through the second pulley plate 5. This acts directly on the V-belt 6, causing a significant decrease in the durability of the V-belt 6. Furthermore, since the second pulley plate 5 is directly moved in the thrust direction by changes in the load on the shaft 2, the winding diameter l of the driven pulley 1 responds sensitively to changes in the load, resulting in changes in the gear ratio. There was also the drawback that the ride was intense and the ride felt unsettling.

In view of the above-mentioned problems with the conventional V-belt automatic transmission mechanism, the present invention has been developed to
When the pulley plate of the V-belt is moved in the thrust direction in response to sudden changes in load on the shaft, it is moved gently, thereby providing the durability of the V-belt and a calm riding feeling. , its feature is that a coil spring is interposed between the second pulley plate of the driven pulley and a cam mechanism that moves this pulley plate in the thrust direction, and the thrust force from the cam mechanism is transferred through the coil spring. The signal is transmitted to the second pulley plate and moved in the thrust direction.

Hereinafter, one embodiment of the V-belt automatic transmission mechanism according to the present invention will be described in detail.

FIG. 3 and FIG. 4 each show a V according to the present invention.
A partially cutaway cross-sectional view of the main part showing the driven pulley 20 of the belt automatic transmission mechanism, and a CC cross-sectional view thereof,
The same parts as in FIGS. 1 and 2 are designated by the same reference numerals.

In FIG. 4, a sleeve 22, which is a sliding member, is fitted onto the circumferential surface of the boss portion 21a of the plate 21 on which the clutch shoe 8 is disposed. A crescent-shaped cam groove 22a is formed at one end of the circumferential surface of the sleeve 22, as shown in FIG. On the other hand, a pin 11 protruding from the inner circumferential surface of the cylindrical wall portion 21 b protrudingly formed on one surface of the plate 21 so as to cover the sleeve 22 is inserted into the front hole cam. It is inserted into the groove 22a. Therefore, the cam groove 22a and the pin 11 constitute a cam mechanism 4 similar to the conventional example shown in FIG. Further, at the other end of the sleeve 22, a guide groove 22b as shown in FIG. 3 is formed along the axial direction of the sleeve 22. Boss part 2 of pulley plate 23 of No. 2
A pin 24 implanted in 3a is inserted. Further, a coil spring 10 is disposed between the flange portion 22c erected on the circumferential surface of the sleeve 22 and the second pulley plate 23, and the elastic force of the coil spring 10 causes the second The pulley plate 23 is constantly pressed so as to sandwich the groove width S of the driven pulley 20.

Therefore, the second pulley plate 23 is
Since the sleeve 22 is locked by the pin 24 and the sleeve 22 is locked to the plate 21 by the cam mechanism 4, these first and second pulley plates 3, 23 and the sleeve 22 and plate 21 are connected to each other. will rotate as one.

Further, the sleeve 22 can be moved by a predetermined length in the thrust direction of the shaft 2 by the cam mechanism 4, and the second pulley plate 23 is connected to the guide groove 22 of the sleeve 22.
b in the thrust direction of the shaft 2. Therefore, according to the driven pulley 20 having the above-described structure, when the load on the shaft 2 changes due to factors such as climbing a slope, the sleeve 22 is moved from the shaft 2 by the torque of the V-belt 6 wound around it and the cam mechanism 4. The coil spring 10 is moved in the thrust direction (direction of arrow B in FIG. 4) to change the set load of the coil spring 10. Thereafter, the coil spring 10 moves to the second pulley plate 2 according to the rate of change in the set load.
3 to move this second pulley plate 23 in the thrust direction of the shaft 2.

In the above embodiment, the cam mechanism 4 for moving the sleeve 22 in the thrust direction of the shaft 2 is connected to the cam groove 2.
2a and the pin 11, the present invention is of course not limited to the above embodiment, and as shown in FIG. 5, in which the same parts in FIG.
A cam surface 21c is formed on the wall portion 21b of the plate 22, and a follower 22d that moves along the cam surface 21c is formed on the flange portion 22c of the sleeve 22, and a cam mechanism is formed from the cam surface 21c and the follower 22d. 4 may be configured.

In addition, in the case of the V-belt automatic transmission mechanism shown in FIG. 5, as shown in FIG. 6 showing the DD cross section of FIG.
is arranged by a spline 30 so as to be slidable but not rotatable with respect to the boss portion 21a,
Further, the plate 21 is formed separately from the boss portion 21a, is loosely fitted into the boss portion 21a, and is attached to the cam surface 21a.
It is arranged so that it can rotate by a predetermined rotational angle along 1c.

As described above, when the second pulley plate of the driven pulley is moved in the thrust direction by the cam mechanism in response to load fluctuations on the shaft, the thrust force for moving the second pulley plate in the thrust direction is applied to the second pulley plate via the spring. Because the transmission is transmitted to the second pulley plate, the second
Since the pulley plate presses the V-belt, the durability of the V-belt is improved, and the spring absorbs sudden changes in the load on the shaft, resulting in stable transmission ratio fluctuations. The riding feeling becomes stable.

[Brief explanation of the drawing]

FIGS. 1 and 2 are partially cutaway sectional views of the main parts of the driven pulley of a conventional V-belt automatic transmission mechanism, and AA sectional views thereof, and FIGS. 3 and 4 are V-belts according to the present invention, respectively. FIG. 5 is a partially cutaway sectional view of the main part showing a driven pulley of an automatic transmission mechanism, and its CC sectional view; FIG. 5 is a partially broken sectional view of the main part showing another embodiment; FIG. 6 is its DD sectional view. . 2...Shaft, 3...First pulley plate, 4
...Cam mechanism, 6...V belt, 10...Coil spring, 20...Driven pulley, 22...
... Sleeve, 22a ... Cam groove, 22b ... Guide groove, 22c ... Flange portion, 23 ... Second pulley plate.

Claims (1)

[Claims for Utility Model Registration] (1) A cam mechanism is interposed between the first pulley plate and the second pulley plate of a driven pulley consisting of a first pulley plate and a second pulley plate. , a V-belt automatic system in which the cam mechanism moves the second pulley plate in the thrust direction of the shaft supporting the driven pulley to change the winding diameter of the V-belt wound around the driven pulley. In the transmission mechanism, a slide member that moves in the thrust direction of the shaft by a cam mechanism is disposed between the first and second pulley plates, and the slide member and the second
A coil spring is interposed between the second pulley plate and the second pulley plate, so that the thrust force applied to the slide member by the cam mechanism is applied to the second pulley plate via the coil spring. Belt automatic transmission mechanism. (2) The slide member consists of a cylindrical sleeve, and a cam groove of the cam mechanism and a guide groove for guiding the second pulley plate in the thrust direction of the shaft are formed at one end and the other end, respectively. , a flange portion supporting one end of the coil spring is formed on the circumferential surface of the V as claimed in claim 1 of the registered utility model claim.
Belt automatic transmission mechanism.