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 by rotational driving of the input shaft, the clutch center being operable to hold a plurality of output-side rotating plates and to be rotationally driven together with the output shaft, the input-side rotating plates and the output-side rotating plates being alternately arranged;
- and
- a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and the output-side rotating plates;
- wherein
- the clutch center includes:
- an output shaft holding portion to which the output shaft is coupled;
- a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface and a center-side slipper cam surface, the center-side assist cam surface being operable to generate a force in a direction from the pressure plate toward 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 pressure plate, the center-side slipper cam surface being operable to cause the pressure plate to move away from the clutch center to reduce the pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate;
- a first through hole located between adjacent ones of the center-side cam portions;
- an outer peripheral wall located radially outward of the center-side cam portions;
- a plurality of center-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 center-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 clutch center;
- 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 center-side cam portion to another center-side cam portion in the center-side cam portions is a first circumferential direction, and a circumferential direction from the another center-side cam portion to the one center-side cam portion is a second circumferential direction, the clutch center is rotatable in the first circumferential direction that is a direction from the center-side assist cam surface to the center-side slipper cam surface of one of the center-side cam portions, and includes a second through hole located ahead, in the first circumferential direction, of an end of the center-side slipper cam surface in the first circumferential direction;
- in the circumferential directions, the oil flow hole is located between an end of the center-side slipper cam surface in the second circumferential direction and the first through hole located ahead, in the first circumferential direction, of the end in the second circumferential direction;
- and
- the second through hole is operable to guide clutch oil flowing outside the clutch center to inside of the clutch center.