Abstract: Improved cooling capacity for a V-belt continuously variable transmission that is compatible with miniaturization of a vehicle body cover is provided in a saddle-ride type vehicle. A concave-shaped space recessed downward is compartmented forward of a seat by a vehicle body cover. An engine unit is supported by the vehicle body frame below the concave-shaped space. The engine unit includes a transmission case formed with a belt chamber in which a V-belt continuously variable transmission is accommodated. An intake duct defines an air passage communicated to the belt chamber. The intake duct is arranged between the transmission case and a leg shield.

Abstract: A friction plate (131) rotates in association with rotation of a pressure plate (77). A first pressing plate (132) presses the friction plate (131) to the right to move the pressure plate (77) to the right. A second pressing plate (133) receives a torque of the pressure plate (77) via the friction plate (131). A slide shaft (231) rotates together with the second pressing plate (133). The operation assist mechanism (220) gives a rightward force to the pressure plate (77), by the slide shaft (231) moving to the right upon receiving the torque from the second pressing plate (133). Balls (135) transmit a portion of the rightward force of the short push rod (43a) to the slide shaft (231) without use of the friction plate (131).

Abstract: A clutch drive device includes an actuator for generating a drive force for driving a clutch, a first solid of revolution, a mechanism for transmitting the drive force of the actuator to the clutch, and an assist spring unit having one end pivotally supported and another end abutting on the solid of revolution. An abutment structure in which the first solid of revolution abuts on the assist spring unit is configured so that an urging force of the assist spring does not act in a direction of rotating the first solid of revolution at least at one position in a play area in which the clutch is not disengaged even if the first solid of revolution rotates.

Abstract: A friction clutch includes a clutch housing having a friction plate, a clutch boss having a clutch plate, a pressure plate, a sub clutch, and a power-assist mechanism. An elastic member urges the pressure plate in a predetermined direction to press the friction plate and the clutch plate into frictional contact with each other when the clutch is engaged. The sub clutch includes a friction plate operatively disposed between first and second pressing plates. The power-assist mechanism receives torque from the pressure plate via the sub clutch when the clutch is disengaged and converts the torque into a force for moving the pressure plate in a direction which separates the pressure plate from a plate group.

Abstract: A compact power unit for a vehicle having a clutch actuator is provided. The power unit includes a clutch actuator and a drive force transmission mechanism for transmitting the drive force of the clutch actuator to the clutch. The clutch actuator and the drive force transmission mechanism are arranged within a casing of the power unit. A drive shaft of the clutch actuator extends in the vertical direction. The drive force transmission mechanism includes a worm shaft coupled to the drive shaft of the clutch actuator, a first solid of revolution including a worm wheel portion which engages the worm shaft, a second solid of revolution which engages a gear portion of the first solid of revolution, and a ball cam. The ball cam converts torque from the second solid of revolution into a force which acts in the axial direction of a slide shaft of the clutch.

Abstract: A friction clutch includes clutch housing having a friction plate, a clutch boss having a clutch plate, a pressure plate, a sub clutch, and a power-assist mechanism. The power-assist mechanism receives torque from the pressure plate when the clutch is disengaged and converts the torque into a force for moving the pressure plate in a direction which separates the pressure plate from a plate group. A cam surface, which supports and guides one or more roller weights, is formed on the pressure plate. The one or more roller weights move outward in a radial direction by a movement amount according to the magnitude of centrifugal force and press the pressure plate toward the plate group with force according to the movement amount.

Abstract: In an engine unit of a straddle type vehicle, a V-belt-type continuously variable transmission (CVT) has a secondary sheave shaft 62 that rotates with a clutch housing of a centrifugal clutch. The secondary sheave shaft is supported in a cantilever fashion via two bearings. The engine unit has a gear that rotates with a clutch boss. Cage-and-roller needle bearings, which are a type of needle bearing, are inserted between the secondary sheave shaft and the gear. In this manner, without enlarging the engine unit, abrasions and deterioration of a bearing inserted between a rotational shaft supported in a cantilever fashion and a body of rotation are prevented.

Abstract: A centrifugal clutch for an engine includes a pressure plate that presses a friction plate into a clutch plate is provided. The clutch may include a plurality of roller weights that move on respective cam surfaces in a radially outward direction relative to the pressure plate in accordance with the magnitude of a centrifugal force generated by rotation of a drive side rotating body. The pressure plate presses the friction plate into the clutch plate with a force corresponding to the amount of movement. An elastic member is operatively coupled to the pressure plate to cause the friction and clutch plates to stay in pressed contact even when the engine is in a stopped state.

Abstract: A motorcycle including a belt type continuously variable transmission (CVT) and having a reduced width. An engine unit includes an engine having a crank shaft, the belt type CVT, a clutch, an output shaft and a generator. The CVT has a primary sheave, a secondary sheave shaft and a secondary sheave. The primary sheave is on one side of the crank shaft and the clutch is on another side with respect to the secondary sheave on the secondary sheave shaft. The output shaft is on a side opposite to the clutch on the secondary sheave shaft. The generator is on the other side of the crank shaft. A center axis of rotation of the secondary sheave shaft is higher than a center axis of rotation of the crank shaft. Right and left footsteps are located behind a rear end of the rotation motor and under a lower end of the secondary sheave.

Abstract: A centrifugal clutch for a vehicle includes a clutch housing having friction plates, a clutch boss having clutch plates, a pressure plate, and roller weights that press the pressure plate in a direction such that the friction plates and the clutch plates are brought into frictional contact with each other when the roller weights receive a centrifugal force. The vehicle power unit includes a main shaft which has an oil supply passage formed therein. The clutch includes a first oil supply path that supplies oil via the oil supply passage to the friction and clutch plates. The clutch includes a second oil supply path that supplies oil via the oil supply passage to the roller weights. The first and second oil supply paths are formed individually to allow independent adjustment of oil supply to each path.

Abstract: In a motorcycle having a V-belt type continuously variable transmission, a resin washer made of a nylon resin is interposed between a boss fixed to a moving sheave half of a secondary sheave and a spring bearing member. The boss contacts the spring bearing member through the resin washer, whereby the moving sheave half is restricted to a Top position, in which a spacing between it and a stationary sheave half becomes maximum. In this manner, the maximum speed is not changed by exchange of the V-belt, the V-belt does not slip or become considerably abraded or deteriorated, and noise generation is suppressed.

Abstract: A motorcycle is provided with a vehicle body, front and rear wheels, an engine and a power transmission mechanism for connecting the engine to the rear wheel. A centrifugal clutch and a transmission having a plurality of gears are arranged in the power transmission mechanism. A handle is provided on the vehicle body. An accelerator grip is provided on the right side of the handle and a clutch lever is provided on the left side. A shift pedal for changing the transmission gear ratio of the transmission and a side stand are provided on the left side of the vehicle body. A rear brake pedal for braking the rear wheel is provided on the right side of the vehicle body. The motorcycle is also provided with a rotation suppression mechanism for suppressing the rotation of the rear wheel at least when the engine is stopped.

Abstract: Abrasion of a V-belt in a belt type continuously variable transmission accommodated in an engine unit of a motorcycle is suppressed. A V-belt wound around and contacting a primary sheave and a secondary sheave 72 is at least partially formed from a resin. A plurality of grooves aligned at a predetermined pitch in a radial direction are formed on sheave surfaces of the primary and secondary sheaves. The average pitch P(mm) of the grooves is P??0.08K×10?3+0.18, where K(Hv) indicates surface hardness of the sheave surfaces.

Abstract: A clutching system comprises a lever mechanism portion and a clutch mechanism portion. The lever mechanism portion comprises a push lever. The push lever comprises a cam surface. The clutch mechanism portion comprises a push rod. The push rod comprises a cam follower. A Belleville spring functions as a clutch spring. The cam surface and the cam follower are formed such that a lever ratio of the push lever at a pivot start position is larger than a lever ratio of the push lever at a pivot finish position. The Belleville spring is formed such that a force required to move the push lever at the pivot finish position is smaller than a force required to move to the push lever at the pivot start position.

Abstract: To enhance the durability of the V-shaped belt by allowing the strength and the heat-radiating property of the resin blocks to stand together at high levels in the V-shaped belt, which has a plurality of resin blocks and endless connecting members connecting the resin blocks. The V-shaped belt includes a plurality of resin blocks arranged in a direction and an endless connecting member that is impacted into the resin blocks and that extends in the arrangement direction of the resin blocks. Depressions are longitudinally and vertically formed in the upside and downside of the front surface and the rear surface of each resin block. The depressions are separated from the connecting member and are also separated from the lateral surfaces of the resin block.

Abstract: A belt type continuous variable transmission comprises a primary sheave, a secondary sheave, and a belt. The primary sheave comprises a first sheave body, a second sheave body that forms between it and the first sheave body a belt groove, about which a belt is entrained, a plurality of push bodies that slide the second sheave body according to centrifugal forces to change a width of the belt groove, and a plurality of stoppers that restrict movements of the push bodies by contacting with outer surfaces of the push bodies when the second sheave body reaches a position of minimum transmission gear ratio, in which the belt groove is made smallest in width. The stoppers are shaped to accelerate partial wear of the outer surfaces of the push bodies.

Abstract: A noise preventing means for a motorcycle including a belt type continuously variable transmission using a resin block belt. An end of an intake duct for inducting cooling air into a belt chamber inside a transmission casing is connected to a front half part of the transmission casing. The intake duct extends upward from the transmission casing, then curves rearward, and extends rearward passing over a seat pillar. An air chamber is connected to a rear end of the intake duct. The intake duct has a curving part curving around the seat pillar.

Abstract: Wear of a V-belt and wear of sheaves in a belt type continuously variable transmission is compatibly prevented. A V-belt wound around a primary sheave \ and a secondary sheave is formed with a resin block belt. A sheave surface of the primary sheave is plated with chrome. The secondary sheave is made of stainless steel and is not plated with chrome. The sheave surface hardness of the secondary sheave is lower than the sheave surface hardness of the primary sheave.

Abstract: To enhance the durability of the V-shaped belt by allowing the strength and the heat-radiating property of the resin blocks to stand together at high levels in the V-shaped belt, which has a plurality of resin blocks and endless connecting members connecting the resin blocks. The V-shaped belt includes a plurality of resin blocks arranged in a direction and an endless connecting member that is impacted into the resin blocks and that extends in the arrangement direction of the resin blocks. Depressions are longitudinally and vertically formed in the upside and downside of the front surface and the rear surface of each resin block. The depressions are separated from the connecting member and are also separated from the lateral surfaces of the resin block.

Abstract: An engine comprises: a V-belt type continuously variable transmission on one side of an engine case, said CVT being provided with and housing in a transmission case a drive pulley attached to one end of a crankshaft, a driven pulley attached to one end of a transmission shaft parallel to said crankshaft, a V-belt routed around the pulleys, said engine case supporting said crankshaft and transmission shaft in a rotatable manner, and a generator attached to the opposite end of said crankshaft in said engine case; in which a filter chamber is disposed in the opposite side surface of said transmission case of said engine case in a depressed manner so as to overlap with at least a part of said generator in the crankshaft direction, and an oil filter for filtering lubricating oil is disposed in said filter chamber.