JP3021885B2 - Front fork device of front and rear wheel drive motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front fork device for a front and rear wheel drive motorcycle.

[0002]

2. Description of the Related Art There is a front fork of a motorcycle called a bottom link type. The bottom link type front fork is
The rear ends of the bottom links are pivotally mounted on the lower ends of the left and right forks, and the front ends of the left and right bottom links are fastened to the front ends of the front axles on which the front wheels are rotatably supported. The cushion unit is connected between the upper part of the fork and the front part of the bottom link, and the cushion unit is expanded and contracted to swing the bottom link about the pivot axis so that the front wheels can be cushioned.

[0003] In some motorcycles, the rear wheels are driven by an engine and the front wheels are also driven so that the vehicle can travel smoothly on slippery road surfaces. In this case, a chain for driving the front wheels is arranged on one side of the front wheels. When the chain is arranged on one side of the front wheel, the chain side of the bottom link must be greatly expanded outward to secure a portion through which the chain passes.

[0004]

An impact is applied to the bottom link when the front wheel passes over an obstacle on the road surface.
Also, a reaction force of the driving torque of the chain driving the front wheels is applied to the chain side of the bottom link. For this reason, the bottom link requires a configuration that can withstand these, and in particular, the bottom link on the chain side is bent outward and expanded, so it is easy to deform,
Because it is thick and durable, there is a disadvantage that the weight increases.

In view of the above, according to the present invention, an arm for pivotally attaching the tip of a pivot shaft is protruded from the bottom link on the side through which the chain passes, and the outer plate of the fork on the side through which the chain passes is extended downward and outward. An object of the present invention is to provide a front fork device of a front-rear wheel drive motorcycle which can tighten a tip end of a pivot shaft to reduce the weight of a bottom link having a large bend.

[0006]

In order to achieve the above object, a front fork device for a front and rear wheel drive motorcycle according to the present invention drives a front wheel and a rear wheel by an engine. An idle sprocket is inserted through one side of the shaft, and a secondary chain and a tertiary chain that drive the front wheels are wound around the shaft. An arm is projected outside the tertiary chain of the bottom link on one side, and the tip of the pivot shaft is mounted on the shaft. At the same time, the outer plate of one of the forks is extended downward and the tip of the pivot shaft is fastened.

[0007]

[Function] The side through which the chain of the bottom link passes is bent outward and greatly expanded. The bottom link on the chain side can receive the impact of the front wheel and the reaction force of the driving torque jointly by the bottom link and the arm, and the bottom link can be reduced in weight. Further, the end of the pivot shaft on which the idle sprocket is mounted is fastened to the outer plate of the fork, so that the rigidity can be increased.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The engine 1 drives a rear wheel 4 via a rear continuously variable belt transmission, a starting clutch and a gear reducer built into an engine case 2, and further via a rear chain 3. Further, the engine 1 is connected via a front continuously variable belt transmission, a starting clutch and a gear reducer to a constant velocity joint 7 attached to a front fork 6 with a primary chain 5, and from the constant velocity joint 7 to a secondary chain. The front wheel 10 is driven via the tier 8 and the tertiary chain 9.

The front fork 6 is a bottom link type fork,
The rear ends of the bottom links 13 are pivotally mounted on the lower ends of the left and right forks 11 with pivot shafts 12, and the front ends of the left and right bottom links 13 are fastened to both ends of a front axle 14 that rotatably supports the front wheel 10. . The cushion unit 1 is located between the upper portions of the left and right forks 11 and the front portions of the left and right bottom links 13.
5, the cushion unit 15 is expanded and contracted, and the bottom link 13 swings about the pivot shaft 12, so that the front wheel 10 can be cushioned.

On one side of the pivot shaft 12, an idle sprocket 16 is inserted and mounted, and the fork 1 is formed into a housing on one side.
1, a constant velocity joint 7 is connected to the front wheel 10 by a secondary chain 8 and a tertiary chain 9 is connected to the front wheel 10. One of the bottom links 13 connects the tertiary chain 9 to the front wheel 1.
In order to connect on one side of 0, it is greatly bent and expanded.
An arm 17 protrudes outward from one of the bottom links 13 in parallel with the tertiary chain 9.
The tip of the pivot shaft 12 is axially mounted on the bearing and the oil seal. Further, one of the forks 11 is a housing-shaped outer plate 1.
The lower end of 9 is extended downward and outward, and is fastened through the tip of the pivot shaft 12.

The arm 17 can share and receive the impact of the front wheel 10 applied to the bottom link 13 on one side through the tertiary chain 9 and the reaction force of the driving torque of the front wheel 10 by the tertiary chain 9. The bottom link 13 can be made lightweight to prevent deformation. Further, the outer plate 19 at the lower end of the one fork 11 can fasten the tip of the pivot shaft 12 to increase the rigidity of the fork 11.

[0012]

As described above, since the present invention is constructed as described above, while increasing the rigidity of the front fork 6,
The bottom link 13 on the side where the tertiary chain 9 passes can be made light and rigid, the difference in weight between the left and right of the front fork 6 can be reduced, and a good handling operation can be performed.

[Brief description of the drawings]

FIG. 1 is a developed front view of a front fork showing an embodiment of the present invention.

FIG. 2 is an overall side view showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 4 Rear wheel 6 Front fork 8 Secondary chain 9 Tertiary chain 10 Front wheel 11 Hawk 12 Pivot shaft 13 Bottom link 16 Idle sprocket 17 Arm 19 Outer plate

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B62K 21/02 B62J 23/00 B62K 25/16 B62M 9/00 B62M 17/00

Claims (1)

(57) [Claims] 1. A front wheel and a rear wheel driven by an engine. An idle sprocket is inserted into one side of a pivot shaft of a bottom link type front fork, and a secondary chain and a tertiary chain for driving a front wheel are wound around the idle sprocket. An arm is projected outside the tertiary chain of the bottom link on one side, the tip of the pivot shaft is attached to the arm, and the outer plate of the one fork is extended downward and the tip of the pivot shaft is fastened. Front fork device for front and rear wheel drive motorcycles.