POWER TRANSMISSION MECHANISM

摘要

PROBLEM TO BE SOLVED: To simplify the release constitution of an excessive load torque. SOLUTION: The winding direction of a spiral spring 47 is set so as to shorten the diameter at the twist deformation time by the action of a load torque generated in a compressor side. When the load torque of the compressor side becomes excessive and exceeds a prescribed value, the twist deformation amount of the spiral spring 47 is increased and the diameter shrink amount is increased. When the diameter shrink change amount of the spiral spring 47 is increased, the displace force to the radius direction inside given to the outer end 47a is increased and the outer end 47a is come off from a regulation surface 43b and the accumulated energizing force of the spiral spring 47 is released. The spiral spring 47 whose energizing force is released is returned back to a natural state and the spiral spring 47 and a engaged recessed place 43 are perfectly separated and the power transmission between the rotor 41 side and rotary shaft 16 side of a pulley 18 is intercepted.