JPH022753B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rear wheel of a chain-driven motorcycle, and more particularly to a buffer structure between a chain sprocket and a rear wheel hub.

Generally, in chain drive motorcycles,
Since engine power is transmitted to the rear wheels through the chain, a large amount of tension is applied to the chain when starting or braking. In order to alleviate such buffering, a buffering mechanism is formed between the rear wheel hub rotatably supported on the rear wheel shaft and the driven side chain sprocket.

This buffer mechanism has conventionally been used, for example, in the
146554, a chain sprocket is rotatably attached to one end of the rear wheel hub, a recess is formed on the side of the rear wheel hub that faces the chain sprocket, and a rubber is inserted into the recess. It houses the damper. Then, a protrusion such as a pin protruding from the chain sprocket is engaged with this rubber damper, and the relative rotational deviation that occurs between the chain sprocket and the rear wheel hub due to the buffering action of the rubber damper is It is designed to absorb buffering.

However, when the rubber damper is compressed due to rotational misalignment between the chain sprocket and the rear wheel hub, the rubber damper deforms in the axial direction of the rear wheel axle. It will receive a load in the thrust direction along the
If this load is large, there is a possibility that the rubber damper may slip out of the recess.

Furthermore, when the rubber damper slips out of the recess and comes into contact with the chain sprocket, a load in the thrust direction is transmitted to the chain sprocket, so there is a risk that unreasonable force will be applied to the shaft support portion of the chain sprocket.

In other words, the chain sprocket is only attached to the outer periphery of one end of the rear wheel hub with a narrow span of wall thickness, so when the thrust force is transmitted as described above, the shaft support part of the chain sprocket There is a problem where the chain sprocket becomes tilted.

The present invention was developed based on the above circumstances, and it is possible to prevent the rubber damper from coming out of the recessed part, and furthermore, it does not apply load in the thrust direction to the chain sprocket. The purpose of the present invention is to provide a rear wheel for a chain-driven motorcycle that can reliably prevent this.

That is, in order to achieve the above object, the present invention
A chain sprocket is rotatably supported at one end of the rear wheel hub which is rotatably supported on the rear wheel shaft, and a recess is formed on the side surface of the rear wheel hub facing the chain sprocket. A plurality of rubber dampers are disposed along the circumferential direction, and these rubber dampers are engaged with protrusions protruding from the chain sprocket to create a buffer acting between the chain sprocket and the rear wheel hub. In a chain-driven motorcycle designed to provide relief, a cover covering a rubber damper is fixed to the side surface of the rear wheel hub, and a through hole is provided in the cover to allow movement of the protrusion in the circumferential direction. It is a feature.

An embodiment of the present invention will be described below based on the drawings.

In the figure, reference numeral 1 indicates a rear wheel axle, and both ends of this rear wheel axle 1 are supported by vehicle bodies 2, 2. A rear wheel hub 4 is rotatably supported on the rear wheel shaft 1 via ball bearings 3a and 3b. This rear wheel hub 4 also serves as a brake drum, and is made of aluminum casting, for example. A small-diameter boss portion 5 is integrally provided at one end of the rear wheel hub 4, and this boss portion 5
is provided coaxially with respect to the rear wheel shaft 1. A driven side chain sprocket 6 is rotatably supported on the outer peripheral surface of the boss portion 5 via a bearing metal 7, and this chain sprocket 6 is provided facing away from one side of the rear wheel hub 4. It is being
A chain 8 is wound around the chain sprocket 6, and this chain 8 is also wound around a drive chain sprocket on the engine side (not shown).

As shown in FIG. 2, an annular recess 9 is formed on one side of the rear wheel hub 4 facing the chain sprocket 6. As shown in FIG. Support walls 10 are formed radially in this concave portion 9 at equal pitches along the circumferential direction. Screw holes 11 for fixing a cover, which will be described later, are formed in these supporting walls 10. Further, in the bottom wall of the concave portion 9, a locking hole 1 for a fan-shaped rubber damper 12 is provided.
3... has been opened. A plurality of fan-shaped rubber dampers 12 are accommodated in the recessed portion 9 along the circumferential direction.

The fan-shaped damper 12 has the structure shown in FIGS. 3A to 3C. That is, the single fan-shaped rubber damper 12 consists of a pair of rubber blocks 13a, 1
3b are integrally connected by a connecting piece 14, and a fitting groove 15 is formed between these rubber blocks 13a and 13b. The aforementioned support wall 10 of the rear wheel hub 4 is fitted into this fitting groove 15 . Further, one rubber block 13a is provided with an engaging protrusion 16 that engages with the engaging hole 13 in the rear wheel hub 4. Also, rubber protrusions 1 are provided on both sides of each rubber block 13a, 13b.
7... is formed.

Such a fan-shaped rubber damper 12 is disposed along the circumferential direction within the concave portion 9 of the rear wheel hub 4, and the supporting wall 10 is fitted between each rubber block 13a, 13b, and the engaging protrusion 16 is locked. It is inserted into the hole 13 and locked. As shown in FIG.
A fitting gap 18 is formed between 2 and 12. These gaps 18 are provided with protrusions protruding from the chain sprocket 6, such as protruding plates 19.
is inserted.

That is, as shown in FIG. 4, the chain sprocket 6 is formed with elongated holes 20 spaced apart from each other at equal pitches in the circumferential direction and extending in the radial direction. One end of the protruding plates 19 is inserted into these elongated holes 20, and these protruding plates 19 are fixed to the chain sprocket 6 by welding 21. The other end of the protruding plate 19 protrudes from the chain sprocket 6 toward the rear wheel hub 4, and is thus fitted into the gap 18 between the sector-shaped rubber dampers 12, 12.

Further, a cover 22 shown in FIGS. 5A and 5B is fixed to the rear wheel hub 4, and covers the fan-shaped rubber dampers 12. The cover 22 is made of a metal plate, and is formed with a through hole 23 through which the protruding plates 19 pass through and allows the protruding plates 19 to move relative to each other in the circumferential direction. Fixing holes 24 are formed to face the formed screw holes 11. The fixing hole 24...
As shown in FIG.
...is screwed on. Therefore, the cover 22 covers one end surface of the rear wheel hub 4 and prevents the fan-shaped rubber damper 12 from being pulled out. Note that the bolts 25 are prevented from loosening by being caulked and engaged with anti-rotation protrusions 26 cut into the cover 22.

Further, in FIG. 1, 30 is a brake shoe plate, 31 is a camshaft, 32 is a brake shoe, 33 is a wheel, and 34 is a spoke.

The operation of the embodiment having such a configuration will be explained.

When starting, suddenly accelerating, or braking, a large tension is applied to the chain 8, but the tension in the chain 8 is due to the chain sprocket 6.
is transmitted to. Since the chain sprocket 6 is rotatably supported on the boss portion 5 of the rear wheel hub 4 via the bearing metal 7, the chain sprocket 6
is rotationally displaced relative to the rear wheel hub 4.
Relative rotation between the chain sprocket 6 and the rear wheel hub 4 results in relative displacement between the protruding plates 19 and the fan-shaped rubber dampers 12, so these rubber dampers 12 are caused to move relative to each other due to their elastic deformation. This absorbs the displacement and thus alleviates the impact generated between the chain sprocket 6 and the rear wheel hub 4. This relieves the tension in the chain 8 and prevents the chain 8 from breaking.

By the way, when the fan-shaped rubber damper 12 is pushed by the protruding plate 19, one of the rubber blocks 13a or 13b is pushed by the protruding plate 19.
Since it is compressed between the support wall 10 and the support wall 10, it is elastically deformed, and during this elastic deformation, a deflection occurs in which it slips out in the thrust direction. Such slippage is also prevented by the engaging protrusion 16, but is also prevented by the cover 22 fixed to the side surface of the rear wheel hub 4. Therefore, the fan-shaped rubber damper 12
... will not come off in the direction of the chain sprocket 6, and there is no risk of the thrust load of the fan-shaped rubber damper 12 being transmitted to the chain sprocket 6.

Therefore, it is possible to prevent the inclination of the chain sprocket 6 and any adverse effects on the shaft support portion of the boss portion.

The cover 22 also prevents mud, dirt, water, etc. thrown up by the rear wheels from entering the recessed portion 9, so that the elastic deformation of the rubber dampers 12 is maintained smoothly.

In this embodiment, the protruding plate 19 protruding from the chain sprocket 6 is fitted into the gap between the rubber dampers, but the invention is not limited to this. A similar effect can be obtained by engaging the plates.

Furthermore, the present invention is not limited to fan-shaped rubber dampers, but can be implemented with rubber dampers of other shapes.

According to the present invention described in detail above, since the rubber damper is prevented from moving in the thrust direction of the rear wheel shaft by the cover fixed to one side of the rear wheel hub, the rubber damper can be securely attached to the rear wheel hub. There is no risk of it slipping out of the recess.

Furthermore, since no force in the thrust direction is transmitted to the chain sprocket, it is possible to prevent inclination of the chain sprocket and adverse effects on the shaft support portion of the boss portion.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a sectional view, FIG. 2 is a view showing one side of the rear wheel hub, FIGS. 3 A to C show a fan-shaped rubber damper, and A is a side view; B and C are cross-sectional views taken along line B-B and line C-C in Fig. 3A, respectively, Fig. 4 is a side view of the chain sprocket, Fig. 5 A and B show the cover, and A is a side view. , B is a sectional view taken along line BB in FIG. 5A. DESCRIPTION OF SYMBOLS 1... Rear wheel axle, 4... Rear wheel hub, 5... Boss part, 6... Chain sprocket, 7... Bearing metal, 9... Concave part, 12... Rubber damper, 1
9... Protruding plate (protrusion), 22... Cover,
23...through hole, 25...bolt.

Claims (1)

[Scope of Claims] 1. A chain sprocket is rotatably supported at one end of a rear wheel hub rotatably supported on a rear wheel shaft,
A concave portion is formed on the side surface of the rear wheel hub facing the chain sprocket, and a plurality of rubber dampers are arranged along the circumferential direction within this concave portion,
In a chain-driven motorcycle, the rubber damper engages a protrusion protruding from the chain sprocket to reduce the impact acting between the chain sprocket and the rear wheel hub. A rear wheel of a chain-driven motorcycle, characterized in that a cover covering a rubber damper is fixed to a side surface of a wheel hub, and a through hole is provided in the cover to allow movement of the projection in the circumferential direction.