JPS6223348Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a front wheel drive device for a motorcycle.

Conventionally, most motorcycles have a structure in which engine power is transmitted to the rear wheels, and the rear wheels are driven, but there are some exceptions in which the front wheels are driven. These motorcycles travel due to the frictional force between the driven rear or front tires and the road surface. However, there is a limit to this frictional force, and on a well-paved road, the frictional force F =
It is said that the limit is 0.8 x W (W = weight added to the drive wheels). Furthermore, on unpaved roads with soft soil or sand on the surface, or on muddy roads, the frictional force becomes extremely small.

If the driving force from the engine is greater than this frictional force, the tires will slip on the road surface.
It does not correspond to running power. This phenomenon is noticeable when starting with wheels that have a large driving force, such as racing motorcycles. In this case, greater driving force can be obtained by driving both the front and rear wheels instead of only driving the rear wheels or the front wheels.

The present invention was developed in light of this point, and is a motorcycle that guides the power of the engine that drives the rear wheels to the front wheels to prevent the tires from spinning when starting or driving in mud. It provides:

The present invention has a structure for this purpose in which the upper end of the front fork, with the front wheel pivotally attached to the lower end, is rotatably supported by the steering head, and the upper and lower ends of the steering head are connected to the vehicle body frame through parallel links so as to be freely swingable. The upper end of a cushion unit that supports the front wheel and receives the vertical swing of the front wheel is pivotally connected to the vehicle body frame, and the lower end of the cushion unit is connected to a link connecting the lower end of the steering head and the vehicle body frame. A drive chain is rotatably attached to a midway portion of the link and is mounted parallel to the link to provide rotational force to the front wheel.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a front fork, and a front wheel 3 is pivotally attached to the lower end of the fork by a shaft 2. The upper part of the front fork 1 is rotatably supported by a steering head 4 and connected to a steering handle (not shown). An arm 5 projects downward from the steering head 4. An upper link 7 is provided between the upper part of the steering head 4 and the vehicle body frame (not shown).
is rotatably connected by shafts 8 and 9,
A lower ring 10 is rotatably mounted between the lower end of the arm 5 and the lower end of the vehicle body frame (not shown) by shafts 11 and 12 so as to maintain a position parallel to the upper link 7. The cushion unit 6 has an upper end 6' pivotally attached to the front end of a vehicle body frame (not shown), and a lower end 6'' pivotally attached to the lower link 10.

The vehicle body frame (not shown) extends rearward from the part to which the cushion unit 6 is pivotally attached.
A swing arm 1 which has an engine 13, a fuel tank, a seat, and a rear wheel 14 pivoted on a shaft 15
It supports a shaft 17 etc. to which the front end of 6 is pivotally connected. The engine 13 has a transmission integrated therein, and has a sprocket 19 attached to its output shaft 18. This sprocket 19 and rear wheel 1
A rear wheel drive chain 21 is spanned between the sprocket 4 and the integral sprocket 20.

An idle sprocket 22 is pivotally connected to the front part of the cushion unit 6 by a shaft 23, and a sprocket (not shown) is provided between the idle sprocket 22 and a sprocket (not shown) that is integrally arranged in parallel with the sprocket 19. , chain 24 is spanned. A sprocket 25 is pivotally attached to the lower part of the steering head 4 by a shaft 26, and a chain 27 is spanned between the sprocket 25 and the idle sprocket 22. Since the shaft 26 of the sprocket 25 swings together with the steering head 4, the line connecting the shaft 23 of the idle sprocket 22 and the shaft 26 of the sprocket 25 always remains parallel to the upper link 7 and the lower link 10. . As shown in FIG. 2, shaft 26 is connected to shaft 29 via a universal joint 28. As shown in FIG.
A sprocket 30 is attached to the shaft 29, and a chain 32 is stretched between the sprocket 30 and a sprocket 31 that is integral with the front wheel 3.

In this motorcycle configured in this way, when the engine 13 operates and the output shaft 18 rotates, the sprocket 1 attached to the output shaft 18 rotates.
9, a rear wheel 14 is driven via a chain 21 and a sprocket 20. At the same time, the sprocket and chain 2 installed in parallel to sprocket 19
4. Idle sprocket 22, sprockets arranged in parallel to this idle sprocket 22, chain 27, sprocket 25, shaft 26, universal joint 28, shaft 29, sprocket 30,
The front wheels 3 are also driven via the chain 32 and sprocket 31.

In this case, when the front wheel 3 swings in the vertical direction while driving, this swing is caused by the swing of the upper link 7 and the lower link 10 (rotation around axes 9 and 12 relative to the vehicle body frame (not shown)). It is then absorbed. That is, when the lower link 10 swings, the lower end 6'' of the cushion unit 6 moves up and down, and the cushion unit 6 thereby moves the front wheel 3.
This will absorb the shock caused by the vertical movement of the And like this, upper link 7 and lower link 1
0 swings, the relationship between the idle sprocket 22, which is pivotally connected to shafts 23 and 26 provided parallel to these, and the sprocket and sprocket 25 that are arranged in parallel with this, is also displaced.
This does not cause strain on the chain 27. Therefore, the distance between the axes 23 and 26 is
9 and between the axes 11 and 12.

In the embodiment described above, a chain was used for all parts of power transmission, but the rear wheel drive part, the front fork drive part of the front wheel, the idle sprocket drive part, etc. were changed to a shaft drive system. You can also do that.

Since the present invention is constructed as described above, the power generated by the engine is effectively transmitted to the front and rear wheels, eliminating tire slippage when starting, and allowing a quick start. This eliminates tire slippage when driving on muddy or sandy roads, making safe driving possible. In addition, the upper link and lower link are installed parallel to each other, and the chain is placed across the sprocket located parallel to these links to transmit power, so even if the front wheel swings up and down, there is no effect on the power transmission. It also has the advantage of not causing any problems.

[Brief explanation of drawings]

FIG. 1 is a side view schematically showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken from FIG. 1. 1...Front fork, 3...Front wheel, 4...
Steering head, 6...Cushion unit, 7...Upper link, 10...Lower link, 13...Engine, 22...Idle sprocket, 25...Sprocket, 27...Chain, 28...Universal joint Into.

Claims (1)

[Scope of utility model registration request] The upper end of the front fork, to which the front wheel is pivoted at the lower end, is rotatably supported on the steering head, and the upper and lower ends of the steering head are swingably supported on the vehicle body frame via parallel links, and The upper end of the cushion unit, which is subject to rocking, is rotatably pivoted to the vehicle body frame, and the lower end of the cushion unit is rotatably pivoted to an intermediate portion of a link connecting the lower end of the steering head and the vehicle body frame. and further, one of the parallel links is made swingable at the same distance as the distance between the respective pivot axes of the parallel links, so that a line connecting the centers thereof is always parallel to the parallel links. The invention is characterized in that two sprocket pivot shafts are provided, a sprocket is pivoted to each of the two shafts, a chain is spanned therebetween, and the front wheel is connected to the output shaft of the engine via the chain. A front wheel drive device for motorcycles.