JPH06166394A - Front and rear wheel drive device for motorcycle - Google Patents

Abstract

PURPOSE:To provide a motorcycle front and rear wheel drive device which can absorb rotation difference between the front and rear wheels of a motor cycle and by which smooth travel on the sands and weak road surface can be realized and which is small and light in weight and can be produced inexpensively. CONSTITUTION:Motive power from an engine 1 is transmitted to a pair of continuously variable belt transmissions 3, 4, and output from one of the pair of continuously variable belt transmission 3, 4 is connected to motive power transmission devices 18, 19 to drive the front wheel, and output from the other side is connected to motive power transmission devices 13, 14 to drive rear wheel, and at the same time respective continuously variable belt, transmission 3, 4 are provided at a vehicle body frame in approximation to the engine 1.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, a motorcycle connects a multi-stage gear transmission to an engine via a manual clutch, further connects to a rear wheel with a chain, and drives the rear wheel to drive the vehicle.
It is designed to steer with front wheels. Then, according to the traveling speed, the transmission gears of the multi-stage gear transmission are appropriately selected and switched to travel. Further, there is one in which the output of the transmission shaft is branched through a differential clutch or the like so that the front wheels are also driven. See, for example, JP-A-58-206477.

[0003]

A motorcycle in which only the rear wheels are driven by the engine cannot run when the rear wheels slip, and cannot run smoothly on sand or soft roads.
Further, in the case of driving the front and rear wheels, it is necessary to provide a differential clutch or a differential device in order to absorb the difference in rotation between the front wheels and the rear wheels. When it does, it is necessary to provide a non-slip device that can travel by transmitting the driving force to the wheels on the other side,
The equipment becomes large-scale, and the manufacturing cost is high. In addition, since the road surface has a large resistance on sandy roads and soft road surfaces, in a multi-stage gear transmission, the vehicle speed greatly decreases while switching gears, which makes it inconvenient to run smoothly.

In view of the above point, the present invention can drive the front wheel and the rear wheel respectively by two continuously variable belt transmissions connected to the crankshaft of the engine to absorb the difference in rotation between the front and rear wheels, and to remove sand and soft road surface. The object of the present invention is to obtain a front-rear wheel drive device for a motorcycle which is small in size, light in weight, and inexpensive to manufacture, as well as being able to travel smoothly and sharing a fixed drive pulley of two continuously variable belt transmissions.

[0005]

In order to achieve the above object, the present invention rotatably supports a front wheel on a vehicle body frame and swings a rear wheel vertically with respect to the vehicle body frame via a swing arm. In a motorcycle in which an engine is mounted on the body frame between the front and rear wheels and the front and rear wheels are driven by the engine so as to be possible, a pair of non-powered vehicles capable of independently transmitting power from the engine at a stepless speed ratio. And a power transmission device for driving the front wheels and an output of one of the pair of continuously variable transmissions connected to a power transmission device for driving the front wheels. The pair of continuously variable belt transmissions are disposed on the vehicle body frame in the vicinity of the engine.

[0006]

[Function] The front and rear wheels are each driven by two continuously variable belt transmissions, which can absorb the rotational difference between the front and rear wheels by the continuously variable transmission and does not require a gear change operation, so that it can be used on sandy or soft roads. You can run smoothly. Further, since one fixed drive pulley shares two two continuously variable belt transmissions, the length of the crankshaft can be shortened and the weight can be reduced.

[0007]

Embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, two continuously variable belt transmissions 3 and 4 are connected to one end of a crankshaft 2 of an engine 1. The two continuously variable belt transmissions 3 and 4 are fixed to one end of the crankshaft 2 and have a common fixed drive pulley 5 having conical surfaces on both sides.
And two movable drive pulleys 6 and 7 slidably provided on the crankshaft 2 on both sides of the fixed drive pulley 5.

As shown in FIG. 3, the movable drive pulleys 6 and 7 have centrifugal weights 8 and 9 respectively built therein, and the centrifugal weights 8 and 9 that spread and move along the slope of the inner wall as the rotation increases are The crankshaft 2 is slid to approach the fixed drive pulley 5, and the diameter of the belt wound around the crankshaft 2 is increased to increase the speed.

As shown in FIGS. 1, 2, 4 and 5, the driven pulley 13 of one continuously variable belt transmission 3 is disposed on the rear side of the crankshaft 2 and has a centrifugal clutch 14 for starting. It is connected to the gear reducer 15 via the chain and further connected to the rear wheel 17 via the chain 16. The driven pulley 18 of the other continuously variable belt transmission 4 is disposed on the front upper side of the crankshaft 2, connected to the gear reducer 20 via a centrifugal clutch 19 for starting, and further connected to the front wheel 22 via a chain 21. Link. As shown in FIGS. 4 and 5, the front hawk 23 to which the front wheels 22 are attached is rotated by the handle 24 to the left and right to steer, and a constant velocity ball joint 26 is provided on the intermediate shaft 25 of the chain 21. There is.

When the engine 1 is rotated (idled), the two continuously variable belt transmissions 3 and 4 rotate. Then, when the rotation of the engine 1 is slightly increased, the centrifugal clutches 14 and 19 for starting are engaged, and the front wheels 22 and the rear wheels 17 are connected.
Is driven to start traveling. When the rotation of the engine 1 is further increased, the continuously variable transmissions 3 and 4 are accelerated, and the traveling speed is increased. The number of fixed drive pulleys 5 of the two continuously variable belt transmissions may be one, and the crankshaft 2 can be made short and compact. Further, as shown in FIG. 4, the engine 1 is mounted on the vehicle body frame 31, and the rear wheel 1
Reference numeral 7 is provided so as to be vertically swingable with respect to the body frame 31 via a swing arm 32.

As shown in FIG. 6, the two driven pulleys 18 of the continuously variable belt transmission 4 on the front side are biased by a spring 27 so as to come into pressure contact with each other, and the two driven pulleys 18 are superposed on each other. A torque cam 28 and a torque pin 29, which are obliquely formed in the tubular portion, are provided and fitted and connected. As the movable drive pulley 7 increases in rotation of the engine 1 and the belt diameter increases, the two driven pulleys 18 spread out against the spring 27, and the belt diameter decreases and the speed increases. or,
When the driving torque of the wheels of the torque cam 28 becomes smaller, the gap between the two driven pulleys 18 becomes wider, the belt diameter becomes smaller, and the speed is increased. The two driven pulleys 13 of the continuously variable transmission 3 on the rear side have the same structure. When the steering wheel is turned off, the front wheel 22 becomes longer than the track of the rear wheel 17 due to the difference in the inner wheel, and the front wheel 22 rotates more than the rear wheel 17. And the front wheel 22
Is pushed by the rear wheels 17, the resistance of the front wheels 22 is reduced, and the continuously variable belt transmission 4 on the front side is accelerated by the action of the torque cam 28 and the torque pin 29 as compared with the continuously variable belt transmission 3 on the rear side. The front and rear continuously variable belt transmissions 3 and 4 can absorb the difference in rotation between the front wheels 22 and the rear wheels 17 and run smoothly.

[0012]

According to the present invention, two continuously variable belt transmissions connected to the crankshaft of an engine can drive front wheels and rear wheels respectively, absorb the difference in rotation between the front wheels and the rear wheels, and achieve continuous variable transmission. It can run smoothly on sand and soft roads. Further, the differential device is not required, the fixed drive pulleys of the two continuously variable transmissions may be one, the crankshaft can be shortened, and the size and weight can be reduced and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical development plan view of an embodiment of the present invention.

FIG. 2 is a side view with a side case removed.

FIG. 3 is an enlarged vertical sectional view of an end portion of a crankshaft.

FIG. 4 is a side view of the entire motorcycle.

FIG. 5 is a plan view of the same.

FIG. 6 is an enlarged vertical sectional view of a driven pulley portion on the front side.

[Explanation of symbols]

 1 engine 2 crankshaft 3,4 continuously variable belt transmission 5 fixed drive pulley 6,7 movable drive pulley 17 rear wheel 22 front wheel

Claims (1)

[Claims] 1. A front wheel is rotatably supported on a vehicle body frame, and a rear wheel is provided so as to be vertically swingable with respect to a vehicle body frame via a swing arm, and an engine is mounted on a vehicle body frame between front and rear wheels. In a motorcycle in which front and rear wheels are driven by an engine, power from the engine is independently transmitted to a pair of continuously variable belt transmissions that can be transmitted at a stepless speed ratio. One of the outputs is connected to a power transmission device that drives the front wheels, and the other output is connected to a power transmission device that drives the rear wheels, and the pair of continuously variable belt transmissions are brought close to the engine. A front and rear wheel drive device for a motorcycle, characterized in that it is arranged on a frame.