Device for transmitting rotational power

A device for transmitting a rotational power from an automobile engine to a compressor for use in an automobile air conditioning system, the compressor including a housing and a drive shaft extending along the axis of the housing, the drive shaft being supported by a bearing on the housing for rotation about the axis of the housing, the device for transmitting a rotational power comprising:

• a pulley supported by the bearing on the housing for rotation about the axis of the housing, for receiving a rotational power from the automobile engine through a V-belt extending between the pulley and the automobile engine;
• a hub connected to the drive shaft;
• connecting means for rotationally connecting the pulley and hub, the connecting means comprising:
• at least one elastic member with defined outer and inner peripheral surfaces;
• a first holder member, defined along the outer periphery of the hub, for holding the at least one elastic member at the radially outer periphery of the at least one elastic member;
• and
• a second holder member, connected to the pulley by holding the bearing for rotationally supporting the pulley on the housing and for holding the at least one elastic member at the radially inner periphery of the at least one elastic member,
• wherein the at least one elastic member is made of an elastic material that is deformable and releasable from at least one of the first and second holder members when a relative rotation between the pulley and drive shaft occurs,
• wherein the first holder member defines a peripheral surface, the peripheral surface of the first holder being substantially complementary to the outer peripheral surface of the elastic member;
• the second holder member defines a peripheral surface, the peripheral surface of the second holder being substantially complementary to the inner peripheral surface of the elastic member,
• the first and second holder members radially cooperating with each other to circumferentially hold the at least one elastic member during normal operation to transmit the rotation, and being disconnected by the deformation of the at least one elastic member when a relative rotation between the pulley and drive shaft occurs,
• wherein the peripheral surface defined by at least one of the first and second holder members has a plurality of outwardly convex and concave portions alternately arranged therealong,
• wherein the at least one elastic member includes a base portion substantially in the form of a ring, and at least one of the outer and the inner peripheral surface of the elastic member has a plurality of outwardly convex and concave portions alternately arranged therealong that are substantially complementary to outwardly convex and concave portions of the peripheral surface of said at least one of the first and second holder members, the outwardly convex portions of the elastic member having an axial length shorter than that of the base portion.