A torque limiting device (51, 151, 251) includes a shaft member (33) that is rotatable by torque, a first cam portion (53, 153, 253), a second cam portion (59, 159, 259) and an urging member (67, 167). The first cam portion (53, 153, 253) is rotatably mounted to the shaft member (33). The second cam portion (59, 159, 259) is mounted to the shaft member (33) so as to be unitarily rotatable therewith and be movable along an axial direction of the shaft member (33). The second cam portion (59, 159, 259) is configured to enable torque transmission between the first cam portion (53, 153, 253) and the second cam portion (59, 159, 259) when engaged with the first cam portion (53, 153, 253) so as to be unitarily rotatable therewith. Additionally, the second cam portion (59, 159, 259) is configured to disable torque transmission between the first cam portion (53, 153, 253) and the second cam portion (59, 159, 259) when disengaged and separated away from the first cam portion (53, 153, 253) along the axial direction. The urging member (67, 167) urges the second cam portion (59, 159, 259) toward the first cam portion (53, 153,253).
