Clutch device and motorcycle

A clutch device that allows or interrupts transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:

• a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft;
• and
• a pressure plate movable toward or away from the clutch center, rotatable relative to the clutch center, holding a plurality of output-side rotating plates, and operable to press the input-side rotating plates and the output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged, wherein
• the pressure plate includes:
• a plurality of pressure-side cam portions each including a pressure-side cam surface operable to generate a force in a direction of causing the pressure plate to move toward or away from the clutch center in order to increase or reduce a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the clutch center;
• a first through hole located between adjacent ones of the pressure-side cam portions;
• an outer peripheral wall located radially outward of the pressure-side cam portions;
• a plurality of pressure-side fitting teeth holding the output-side rotating plates, projecting radially outward from an outer peripheral surface of the outer peripheral wall, and arranged in circumferential directions;
• a plurality of spline grooves each located between adjacent ones of the pressure-side fitting teeth;
• and
• an oil flow hole located in the spline grooves to penetrate the outer peripheral wall to allow clutch oil flowing at an inner peripheral side of the outer peripheral wall to be discharged to outside of the pressure plate, and
• assuming a direction in which the pressure plate approaches the clutch center is a first direction, a direction in which the pressure plate moves away from the clutch center is a second direction, a circumferential direction from one pressure-side cam portion to another pressure-side cam portion is a first circumferential direction, and a circumferential direction from the another pressure-side cam portion to the one pressure-side cam portion is a second circumferential direction,
• the pressure plate is rotatable in the first circumferential direction with respect to the pressure-side cam surface at an end of one of the pressure-side cam portions in the second circumferential direction, and
• in the circumferential directions, the oil flow hole is located between an end of the pressure-side cam surface in the first circumferential direction and the first through hole located ahead, in the second circumferential direction, of the end in the first circumferential direction.

A clutch device that allows or interrupts transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:

• a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft;
• and
• a pressure plate movable toward or away from the clutch center, rotatable relative to the clutch center, holding a plurality of output-side rotating plates, and operable to press the input-side rotating plates and the output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged, wherein the clutch center includes:
• an output shaft holding portion to which the output shaft is coupled;
• and
• a boss located radially outward of the output shaft holding portion and extending toward the pressure plate, and the pressure plate includes:
• a plurality of pressure-side cam portions each including a pressure-side cam surface operable to generate a force in a direction of causing the pressure plate to move toward or away from the clutch center in order to increase or reduce a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the clutch center;
• an insertion hole in which the boss is inserted;
• an outer peripheral wall located radially outward of the pressure-side cam portions;
• a plurality of pressure-side fitting teeth holding the output-side rotating plates, projecting radially outward from an outer peripheral surface of the outer peripheral wall, and arranged in circumferential directions;
• a plurality of spline grooves each located between adjacent ones of the pressure-side fitting teeth;
• and
• an oil flow hole located in the spline grooves to penetrate the outer peripheral wall to allow clutch oil flowing at an inner peripheral side of the outer peripheral p wall to be discharged to outside of the pressure plate, and
• assuming a direction in which the pressure plate approaches the clutch center is a first direction, a direction in which the pressure plate moves away from the clutch center is a second direction, a circumferential direction from one pressure-side cam portion to another pressure-side cam portion is a first circumferential direction, and a circumferential direction from the another pressure-side cam portion to the one pressure-side cam portion is a second circumferential direction,
• the pressure plate is rotatable in the first circumferential direction with respect to the pressure-side cam surface at an end of one of the pressure-side cam portions in the second circumferential direction, and
• in the circumferential directions, the oil flow hole is located between an end of the pressure-side cam surface in the second circumferential direction and the insertion hole located ahead, in the first circumferential direction, of the end in the second circumferential direction.

A clutch device that allows or interrupts transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:

• a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft;
• and
• a pressure plate movable toward or away from the clutch center, rotatable relative to the clutch center, holding a plurality of output-side rotating plates, and operable to press the input-side rotating plates and the output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged, wherein
• the pressure plate includes:
• a plurality of pressure-side cam portions each including a pressure-side assist cam surface and a pressure-side slipper cam surface, the pressure-side assist cam surface being operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the clutch center, the pressure-side slipper cam surface being operable to cause the pressure plate to move away from the clutch center in order to reduce a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the clutch center;
• a first through hole located between adjacent ones of the pressure-side cam portions;
• an outer peripheral wall located radially outward of the pressure-side cam portions;
• a plurality of pressure-side fitting teeth holding the output-side rotating plates, projecting radially outward from an outer peripheral surface of the outer peripheral wall, and arranged in circumferential directions;
• a plurality of spline grooves each located between adjacent ones of the pressure-side fitting teeth;
• and
• an oil flow hole located in the spline grooves to penetrate the outer peripheral wall to allow clutch oil flowing at an inner peripheral side of the outer peripheral wall to be discharged to outside of the pressure plate, and
• assuming a direction in which the pressure plate approaches the clutch center is a first direction, a direction in which the pressure plate moves away from the clutch center is a second direction, a circumferential direction from one pressure-side cam portion to another pressure-side cam portion is a first circumferential direction, and a circumferential direction from the another pressure-side cam portion to the one pressure-side cam portion is a second circumferential direction,
• the pressure plate is rotatable in the first circumferential direction that is a direction from the pressure-side slipper cam surface to the pressure-side assist cam surface of one of the pressure-side cam portions, and
• in the circumferential directions, the oil flow hole is located ahead, in the second circumferential direction, of an intermediate point in the circumferential directions between an end of the pressure-side assist cam surface in the first circumferential direction and an end of the pressure-side slipper cam surfaces in the first circumferential direction located ahead, in the first circumferential direction, of the end in the first circumferential direction.