Clutch device

A clutch device to allow or block 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 rotationally drivable by 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, and to be rotatable with respect to, the clutch center, the pressure plate being configured to hold one or more of a plurality of output-side rotating plates alternately arranged with the plurality of input-side rotating plates, the pressure plate being configured to press the plurality of input-side rotating plates and the plurality of output-side rotating plates;
• a clutch spring to urge the pressure plate in a first direction where the first direction is a direction in which the pressure plate moves toward the clutch center and a second direction is a direction in which the pressure plate moves away from the clutch center;
• and
• a lifter plate secured to the pressure plate to restrict movement of the pressure plate away from the clutch center in the second direction by a predetermined distance or longer;
• wherein
• an end, on the side of the first direction, of the clutch spring is in contact with the lifter plate, and an end, on the side of the second direction, of the clutch spring is in contact with the clutch center;
• the clutch center includes:
• a center-side assist cam surface to generate a force in a direction from the pressure plate toward the clutch center, in order to increase a pressing force between the plurality of input-side rotating plates and the plurality of output-side rotating plates, when the clutch center rotates with respect to the pressure plate;
• and
• a housing portion located to the side of the center-side assist cam surface in a rotation direction of the clutch center, the housing portion housing the clutch spring;
• the pressure plate includes:
• a pressure-side assist cam surface configured to be contactable with the center-side assist cam surface, and to generate a force in a direction from the pressure plate toward the clutch center in order to increase the pressing force between the plurality of input-side rotating plates and the plurality of output-side rotating plates, when the pressure plate rotates with respect to the clutch center;
• and
• the clutch device includes a reducer to reduce a restoring force of the clutch spring in a direction from the clutch spring toward the center-side assist cam surface during a time period until the center-side assist cam surface and the pressure-side assist cam surface approach and contact each other from a state of being spaced apart from each other in the rotation direction.