| CPC F16D 23/12 (2013.01) [F16D 13/56 (2013.01); F16D 13/70 (2013.01); F16D 13/52 (2013.01); F16D 2013/565 (2013.01); F16D 2023/123 (2013.01)] | 19 Claims |

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1. A clutch device to allow or interrupt 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 and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein
the pressure plate includes:
a body; and
a plurality of pressure-side cam portions, assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction, each of the pressure-side cam portions projecting from a surface of the body at a side of the first direction in the first direction, being located radially outward of the output shaft, and 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 the pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the clutch center;
at least one of the pressure-side cam portions includes a first pressure-side recess located between the pressure-side assist cam surface and the pressure-side slipper cam surface with respect to circumferential directions and recessed in the second direction from a surface of the pressure-side cam portion at a side of the first direction; and
an entire periphery of the first pressure-side recess is surrounded by the surface of the pressure-side cam portion at the side of the first direction, when seen in an axial direction of the output shaft.
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