Electromagnetic clutch

An electromagnetic clutch comprising:

• a rotatable shaft;
• a field coil having an energizing coil mounted on the shaft;
• an output-side rotary member which is non-rotatably mounted on the shaft on a side opposing to the field coil;
• an input-side rotary member which is rotatably mounted on the shaft;
• a drive transmitting member rotatable together with the input-side rotary member for transmitting a drive power from the input-side rotary member to the output-side rotary member;
• and
• an elastic member for allowing the drive transmitting member to shift from the input-side rotary member side to the output-side rotary member side when the energizing coil is energized, wherein
• the input-side rotary member includes a tubular part into which the shaft is inserted and a plurality of slip stopper projections formed at a lead end on an outer periphery of the tubular part circumferentially at a certain interval,
• the drive transmitting member is formed with a through hole and a plurality of radially inwardly protruding projections at respective positions corresponding to spaces between the adjacent slip stopper projections, the drive transmitting member being held on the input-side rotary member in a state that the tubular part is fitted in the through hole of the drive transmitting member, and
• the elastic member in a ring shape resilient material having a radial thickness greater than a radial distance between an outer surface of the tubular part of the input-side rotary member and an innermost end of the projection of the drive transmitting member mounted on the tubular part, the elastic member being mounted on the tubular part between the slip stopper projections and the drive transmitting member.