Clutch apparatus

A clutch apparatus to transmit a rotational driving force of an input shaft to an output shaft or cut off the rotational driving force, the clutch apparatus comprising:

• a clutch center housed in a clutch housing holding input-side rotary plates to be rotationally driven in response to rotational driving of the input shaft, the clutch center being rotationally drivable together with the output shaft;
• a pressure plate movable toward or away from the clutch center, the pressure plate holding at least one of output-side rotary plates positioned alternately with the input-side rotary plates, the pressure plate being able to push the input-side rotary plates and the output-side rotary plates;
• and
• a stopper plate secured to the pressure plate, where a direction in which the pressure plate is movable toward and away from the clutch center is a movement direction, a direction in which the pressure plate is movable toward the clutch center is a first direction, and a direction in which the pressure plate is movable away from the clutch center is the second direction;
• wherein
• the clutch center includes:
• center-side cam portions including center-side assist cam surfaces to, upon rotation of the clutch center relative to the pressure plate, produce a force in a direction from the pressure plate toward the clutch center so as to increase a pushing force for the input-side rotary plates and the output-side rotary plates;
• the pressure plate includes:
• pressure-side cam portions including pressure-side assist cam surfaces to, upon rotation of the pressure plate relative to the clutch center, produce a force in the direction from the pressure plate toward the clutch center so as to increase the pushing force for the input-side rotary plates and the output-side rotary plates;
• and
• pressure-side cam holes each extending through a portion of the pressure plate located between adjacent ones of the pressure-side cam portions;
• where a direction from a first side toward a second side in a circumferential direction of the pressure plate is a first circumferential direction and a direction from the second side toward the first side in the circumferential direction of the pressure plate is a second circumferential direction, the pressure plate and the clutch center are rotatable in the first circumferential direction;
• and
• with the center-side assist cam surfaces and the pressure-side assist cam surfaces in contact with each other, a first clearance communicating with the pressure-side cam hole is provided in the second circumferential direction relative to an end of the center-side assist cam surface facing in the second circumferential direction when viewed in an axial direction of the output shaft.

A clutch apparatus to transmit a rotational driving force of an input shaft to an output shaft or cut off the rotational driving force, the clutch apparatus comprising:

• a clutch center housed in a clutch housing holding input-side rotary plates to be rotationally driven in response to rotational driving of the input shaft, the clutch center being rotationally drivable together with the output shaft;
• a pressure plate movable toward or away from the clutch center, the pressure plate holding at least one of output-side rotary plates positioned alternately with the input-side rotary plates, the pressure plate being able to push the input-side rotary plates and the output-side rotary plates;
• and
• a stopper plate secured to the pressure plate, where a direction in which the pressure plate is movable toward and away from the clutch center is a movement direction, a direction in which the pressure plate is movable toward the clutch center is a first direction, and a direction in which the pressure plate is movable away from the clutch center is the second direction;
• wherein
• the clutch center includes:
• center-side cam portions including center-side assist cam surfaces to, upon rotation of the clutch center relative to the pressure plate, produce a force in a direction from the pressure plate toward the clutch center so as to increase a pushing force for the input-side rotary plates and the output-side rotary plates;
• the pressure plate includes:
• pressure-side cam portions including pressure-side assist cam surfaces to, upon rotation of the pressure plate relative to the clutch center, produce a force in the direction from the pressure plate toward the clutch center so as to increase the pushing force for the input-side rotary plates and the output-side rotary plates;
• and
• pressure-side cam holes each extending through a portion of the pressure plate located between adjacent ones of the pressure-side cam portions;
• where a direction from a first side toward a second side in a circumferential direction of the pressure plate is a first circumferential direction and a direction from the second side toward the first side in the circumferential direction of the pressure plate is a second circumferential direction, the pressure plate and the clutch center are rotatable in the first circumferential direction;
• and
• with the center-side assist cam surfaces and the pressure-side assist cam surfaces in contact with each other, a clearance communicating with the pressure-side cam hole is provided in the first circumferential direction relative to an end of the pressure-side assist cam surface facing in the first circumferential direction when viewed in an axial direction of the output shaft.

A clutch apparatus to transmit a rotational driving force of an input shaft to an output shaft or cut off the rotational driving force, the clutch apparatus comprising:

• a clutch center housed in a clutch housing holding input-side rotary plates to be rotationally driven in response to rotational driving of the input shaft, the clutch center being rotationally drivable together with the output shaft;
• a pressure plate movable toward or away from the clutch center, the pressure plate holding at least one of output-side rotary plates positioned alternately with the input-side rotary plates, the pressure plate being able to push the input-side rotary plates and the output-side rotary plates;
• and
• a stopper plate secured to the clutch center and contactable with the pressure plate to prevent the pressure plate from moving away from the clutch center in a second direction by a predetermined distance or more, where a direction in which the pressure plate is movable toward and away from the clutch center is a movement direction, a direction in which the pressure plate is movable toward the clutch center is a first direction, and a direction in which the pressure plate is movable away from the clutch center is the second direction;
• wherein
• the clutch center includes:
• center-side cam portions including center-side assist cam surfaces to, upon rotation of the clutch center relative to the pressure plate, produce a force in a direction from the pressure plate toward the clutch center so as to increase a pushing force for the input-side rotary plates and the output-side rotary plates;
• and
• center-side cam holes each extending through a portion of the clutch center located between adjacent ones of the center-side cam portions;
• the pressure plate includes:
• pressure-side cam portions including pressure-side assist cam surfaces to, upon rotation of the pressure plate relative to the clutch center, produce a force in the direction from the pressure plate toward the clutch center so as to increase the pushing force for the input-side rotary plates and the output-side rotary plates;
• where a direction from a first side toward a second side in a circumferential direction of the pressure plate is a first circumferential direction and a direction from the second side toward the first side in the circumferential direction of the pressure plate is a second circumferential direction, the pressure plate and the clutch center are rotatable in the first circumferential direction;
• and
• with the center-side assist cam surfaces and the pressure-side assist cam surfaces in contact with each other, a clearance communicating with the center-side cam hole is provided in the first circumferential direction relative to an end of the pressure-side assist cam surface facing in the first circumferential direction when viewed in an axial direction of the output shaft.