Clutch device

A clutch device comprising:

• a housing;
• a prime mover including a stator fixed to the housing, and a rotor rotatable relative to the stator, the prime mover being capable of outputting torque from the rotor by supply of electric power to the prime mover;
• a speed reducer configured to reduce torque of the prime mover and output the reduced torque;
• a rotational translation unit including a rotation portion that rotates relative to the housing upon receiving an input of the torque output from the speed reducer, and a translation portion that moves relative to the housing in an axial direction in accordance with rotation of the rotation portion relative to the housing;
• a clutch provided between a first transmission portion and a second transmission portion that are rotatable relative to the housing, the clutch being configured to allow transmission of torque between the first transmission portion and the second transmission portion in an engaged state of the clutch, and interrupt the transmission of torque between the first transmission portion and the second transmission portion in a disengaged state of the clutch;
• and
• a state changing unit configured to receive a force along the axial direction from the translation portion and change a state of the clutch to the engaged state or the disengaged state according to a position of the translation portion in the axial direction relative to the housing, wherein
• cogging torque generated between the rotor and the stator is set to such a magnitude that the rotor is stoppable at any rotation position relative to the stator.