Abstract: A multi-plate clutch system includes: a pressure plate which is biased by a clutch spring in a direction in which driving friction plates and driven friction plates are brought into pressure contact with each other; and at least one of assist device configured to increase a pressure contact force when torque is changed for acceleration and the slipper device configured to decrease the pressure contact force when the torque is changed for deceleration. A ring member whose inner peripheral surface is put in sliding contact with an outer peripheral surface of one cam plate out of paired cam plates, which are included in at least one of the assist device and the slipper device, is fixed to a clutch inner, and oil discharging passages for guiding oil to a sliding contact portion between the one cam plate and the ring member are provided in outer peripheral edge portions of concave cams formed in the one cam plate.

Abstract: A multi-plate clutch includes clutch discs which are disposed between a clutch outer and a clutch inner and are movable in an axial direction of the transmission shaft to permit and cut off the transmission of the rotational driving force from a crankshaft to a transmission shaft. A first biasing mechanism is configured to apply a clamping force to the clutch discs. A cam mechanism is configured to adjust the clamping force in accordance with the rotational driving force. A second biasing mechanism is configured to generate a biasing force to separate the clutch discs away from one another and to weaken the clamping force. The cam mechanism is configured to apply to the second biasing mechanism a force against the biasing force generated by the second biasing mechanism in accordance with the rotational driving force.

Abstract: A multiplate clutch includes at least one driving friction plate configured to be rotated by a driving portion, at least one driven friction plate provided to face the at least one driving friction plate and configured to rotate the driven portion, a pressure applying unit configured to apply a pressing force to the at least one driving friction plate and the at least one driven friction plate to transmit the driving force from the driving portion to the driven portion via the at least one driving friction plate and the at least one driven friction plate, a first cam unit including first concave-convex cams and configured to increase the pressing force in accordance with an increase of the driving force, and a second cam unit configured to function as a back torque limiter mechanism and including second concave-convex cams which are different from the first concave-convex cams.

Abstract: A motorcycle includes a swing arm, a rear wheel mounted on a leading end of the swing arm, a drive shaft disposed in the swing arm, and a final gear transmission mechanism interposed between the drive shaft and the rear wheel. The final gear transmission mechanism includes a gear case mounted on the leading end of the swing arm for supporting a rear axle; a first end bearing and a second end bearing for supporting a first end and a second end of the rear axle, respectively, a ring gear mounted on the rear axle for transmitting the rotary drive force of an engine to the rear axle; a holding portion for holding the first end of the rear axle in the axial direction of the rear axle; and a fastening member for fastening the second end bearing to the second end of the rear axle.

Abstract: A multi-plate clutch system includes: a pressure plate which is biased by a clutch spring in a direction in which driving friction plates and driven friction plates are brought into pressure contact with each other; and at least one of assist device configured to increase a pressure contact force when torque is changed for acceleration and the slipper device configured to decrease the pressure contact force when the torque is changed for deceleration. A ring member whose inner peripheral surface is put in sliding contact with an outer peripheral surface of one cam plate out of paired cam plates, which are included in at least one of the assist device and the slipper device, is fixed to a clutch inner, and oil discharging passages for guiding oil to a sliding contact portion between the one cam plate and the ring member are provided in outer peripheral edge portions of concave cams formed in the one cam plate.

Abstract: A pressure plate is movable in an axial direction to cause multiple driving friction plates and driven friction plates to come in pressure contact with each other. The pressure plate is biased by a clutch spring in a direction to bring the driving friction plates and the driven friction plates in pressure contact with each other. When acceleration torque is changed, an assist mechanism increases the pressure-contact force of the pressure plate. A pressure plate and a clutch inner are connected together and are capable of being separated from each other in an axial direction. When an assist mechanism increases a pressure-contact force of the pressure plate, the pressure plate is moved in a direction to bring driving and driven friction plates into pressure contact with each other, while the clutch inner is moved relative to the pressure plate in the same direction so as to be detached from the pressure plate.

Abstract: A multiplate clutch has an assistive cam mechanism comprising a first cam member having a first recess and a second cam member having a first tooth inserted in the first recess, wherein at least one of abutment surfaces of the first recess and the first tooth in a power transmitting state for transmitting power from an input member to an output member comprises a slanted surface for increasing an urging force of a clutch spring upon acceleration in the power transmitting state. The multiplate clutch is prevented from being connected abruptly while sufficiently reducing a load with which to operate the clutch. The angle of intersection between the slanted surfaces and a plane perpendicular to a clutch central axis is set to a range from 80 degrees to 85 degrees.

Abstract: A multi-plate clutch includes clutch discs which are disposed between a clutch outer and a clutch inner and are movable in an axial direction of the transmission shaft to permit and cut off the transmission of the rotational driving force from a crankshaft to a transmission shaft. A first biasing mechanism is configured to apply a clamping force to the clutch discs. A cam mechanism is configured to adjust the clamping force in accordance with the rotational driving force. A second biasing mechanism is configured to generate a biasing force to separate the clutch discs away from one another and to weaken the clamping force. The cam mechanism is configured to apply to the second biasing mechanism a force against the biasing force generated by the second biasing mechanism in accordance with the rotational driving force.

Abstract: A motorcycle includes a swing arm, a rear wheel mounted on a leading end of the swing arm, a drive shaft disposed in the swing arm, and a final gear transmission mechanism interposed between the drive shaft and the rear wheel. The final gear transmission mechanism includes a gear case mounted on the leading end of the swing arm for supporting a rear axle; a first end bearing and a second end bearing for supporting a first end and a second end of the rear axle, respectively, a ring gear mounted on the rear axle for transmitting the rotary drive force of an engine to the rear axle; a holding portion for holding the first end of the rear axle in the axial direction of the rear axle; and a fastening member for fastening the second end bearing to the second end of the rear axle.

Abstract: A multiplate clutch includes at least one driving friction plate configured to be rotated by a driving portion, at least one driven friction plate provided to face the at least one driving friction plate and configured to rotate the driven portion, a pressure applying unit configured to apply a pressing force to the at least one driving friction plate and the at least one driven friction plate to transmit the driving force from the driving portion to the driven portion via the at least one driving friction plate and the at least one driven friction plate, a first cam unit including first concave-convex cams and configured to increase the pressing force in accordance with an increase of the driving force, and a second cam unit configured to function as a back torque limiter mechanism and including second concave-convex cams which are different from the first concave-convex cams.

Abstract: A dry multi-disc clutch includes a plurality of friction discs interposed between a drive-side clutch outer and a driven-side clutch center and power is transmitted from the clutch outer to the clutch center by pushing these friction discs using a pressure plate. Fins which enhance a flow of air are formed on the clutch outer and the pressure plate and, at the same time, passages which allow the communication of air are formed in the clutch outer and the pressure plate. With such a clutch structure it is possible to efficiently radiate the friction heat, which is generated when the clutch is connected, and the heat transmitted from the engine and, at the same time, it is possible to discharge the wear powder that is generated when the clutch is connected. As a result, it is possible to stabilize the clutch performance.

Abstract: A dry multi-disc clutch includes a plurality of friction discs interposed between a drive-side clutch outer and a driven-side clutch center and power is transmitted from the clutch outer to the clutch center by pushing these friction discs using a pressure plate. Fins which enhance a flow of air are formed on the clutch outer and the pressure plate and, at the same time, passages which allow the communication of air are formed in the clutch outer and the pressure plate. With such a clutch structure it is possible to efficiently radiate the friction heat, which is generated when the clutch is connected, and the heat transmitted from the engine and, at the same time, it is possible to discharge the wear powder that is generated when the clutch is connected. As a result, it is possible to stabilize the clutch performance.