JPH0657552B2 - Front and rear wheel drive for motorcycles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a continuously variable transmission cooling device for a front-rear wheel-drive motorcycle suitable for traveling on sand or a soft road surface.

(Prior Art) Generally, in a motorcycle, a multi-stage gear transmission is connected to an engine through a manual clutch, and further, a chain is connected to a rear wheel, the engine drives the rear wheel to drive, and the front wheel steers. It is supposed to do. 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.

(Problems to be Solved by the Invention) A motorcycle in which only the rear wheels are driven by an engine cannot run when the rear wheels slip, and cannot run smoothly on sand or soft roads. In the case of driving the front and rear wheels,
In order to absorb the difference in rotation between the front wheels and the rear wheels, it is necessary to provide a differential clutch or a differential device, and when the wheels on one side slip, the differential device is applied to the wheels on the other side. Since it is necessary to provide a non-slip device that can travel by transmitting the driving force, the size of the device becomes large and the manufacturing cost becomes 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 this point, the present invention can drive the front wheel and the rear wheel with 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 smooth sandy roads and soft roads. An object of the present invention is to obtain a front-rear wheel drive device for a motorcycle that can be driven and can be shared by a fixed drive pulley of two continuously variable belt transmissions, can be cooled, and can be produced at a small size, light weight and at low cost.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention connects two continuously variable belt transmissions for driving front wheels and rear wheels to one end of a crankshaft of an engine, A fixed drive pulley common to the two continuously variable belt transmissions is attached to the one end of the fixed drive pulley, two movable drive pulleys are slidably attached to the crankshaft on both sides of the fixed drive pulley, and the inside of the fixed drive pulley is attached. The plurality of fans are radially provided in the hollow portion formed in the fixed portion with the crankshaft, and the fixed portion is provided with a plurality of slits communicating with the core hole of the crankshaft and opening in the hollow portion. Especially.

(Operation) The front and rear wheels are each driven by two continuously variable belt transmissions, which can absorb the rotation difference between the front and rear wheels by continuously variable transmission and does not require a gear change operation. Can be run smoothly. Further, since one fixed drive pulley is shared by two continuously variable belt transmissions, the length of the crankshaft can be shortened and the weight can be reduced.
In the fixed drive pulley, the belts of the two continuously variable belt transmissions come into contact with each other on both sides to generate frictional heat. The temperature of the belt can be prevented from being raised by the cooling air flowing through the cavity to the hollow portion and flowing out to the outside of the fixed drive pulley, so that the belt can be made durable.

(Example) Hereinafter, the Example of this invention is described with reference to 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 both sides of the fixed drive pulley 5 slide on the crankshaft 2. Two movable drive pulleys 6 and 7 movably provided
Consists of.

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 slopes of the inner wall as the rotation rises allow the crankshaft to move. 2 slides closer to the fixed drive pulley 5, and the diameter of the belt wound around is increased to increase the speed.

As shown in FIGS. 3 and 4, the fixed drive pulley 5 fixed to the crankshaft 2 has a hollow portion 10 formed inside,
A plurality of fans 11 are provided radially from a fixed portion 5a for fixing to the crankshaft 2, and a plurality of slits 5b communicating with the core hole 12 of the crankshaft 2 and opened to the hollow portion 10 are provided in the fixed portion 5a. There is.

As shown in FIG. 1, FIG. 2, FIG. 5, and FIG. 6, the driven pulley 13 of one continuously variable belt transmission 3 is arranged on the rear side of the crankshaft 2, and the starting centrifugal clutch 14 is arranged. 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, is connected to the gear reducer 20 via the centrifugal clutch 19 for starting, and is further connected to the front wheel 22 via the chain 21. Link. As shown in FIGS. 5 and 6, the front fork 23 with the front wheel 22 attached thereto.
The steering wheel 24 is rotated right and left for steering, and a constant velocity ball joint 26 is provided on the intermediate shaft 25 of the chain 21.

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 starting centrifugal clutch 1
4, 19 are connected, the front wheels 22 and the rear wheels 17 are driven, and traveling is started. 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, and the fixed drive pulley 5 can rotate the fan synchronized with the rotation of the crankshaft 2. Since it is cooled by the cooling air flowing from the core hole 12 to the cavity 10 through the slit 5b of the fixing portion 5a, the temperature rise due to friction is prevented and the durability of the belt is improved.

As shown in FIG. 7, 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 arranged in a superposed cylinder. A torque cam 28 and a torque pin 29, which are obliquely formed in the 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, and the belt diameter decreases and the speed increases. Further, when the driving torque of the wheels of the torque cam 28 becomes small, the gap between the two driven pulleys 18 is widened, the belt diameter becomes small, 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. Then, the front wheels 22 are pushed by the rear wheels 17, so that the resistance of the front wheels 22 becomes small and the front continuously variable belt transmission 4
Is increased by the action of the torque cam 28 and the torque pin 29 from the continuously variable belt transmission 3 on the rear side, and the front and rear continuously variable belt transmissions 3 and 4 absorb the difference in rotation between the front wheels 22 and the rear wheels 17 for smoothing. You can drive to.

(Effects of the Invention) As described above, the present invention is configured as described above, and the two continuously variable belt transmissions connected to the crankshaft of the engine drive the front wheels and the rear wheels, respectively. It can absorb the difference in rotation between the rear wheels and can travel smoothly on sandy or soft roads by continuously variable transmission. Further, a differential device is not required, and only one fixed drive pulley for two continuously variable transmissions is required, the crankshaft can be shortened, and the size, weight and cost can be reduced. The fixed drive pulley has a large amount of frictional heat caused by the belt hitting both sides, but cooling air can flow through the cavity to cool it, and the durability of the belt is also good.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a vertical exploded plan view, FIG. 2 is a side view with a side case removed, FIG. 3 is an enlarged vertical sectional view of a crankshaft end, and FIG. A central sectional view of the fixed drive pulley, FIG. 5 is an overall side view, FIG. 6 is a plan view of the same, and FIG. 7 is an enlarged vertical sectional view of a driven pulley portion on the front side. 1 ... Engine, 2 ... Crankshaft, 3 ... Stepless belt transmission, 4 ... Stepless belt transmission, 5 ... Fixed drive pulley, 6 ... Movable drive pulley, 7 ... Movable drive pulley, 10 ... cavity, 11 ... Juan, 12 ... core hole,
17 ... rear wheel, 22 ... front wheel.

Claims (1)

[Claims] 1. A crankshaft of an engine is connected to two endless belt transmissions for driving front wheels and rear wheels, respectively, and one end of the crankshaft is common to both endless belt transmissions. A fixed drive pulley is attached, two movable drive pulleys are slidably attached to the crankshaft on both sides of the fixed drive pulley, and a hollow portion formed inside the fixed drive pulley is provided with a fixed portion with the crankshaft. A front and rear wheel drive device for a motorcycle, wherein a plurality of fans are provided radially and a plurality of slits are provided in the fixing portion so as to communicate with a core hole of a crankshaft and open into the cavity.