Patent ID: 7721863

Claim:
An electromagnetic clutch comprising: an electromagnet coil through which a current is caused to flow; a rotor to which power is transmitted from the outside; an armature plate facing to the rotor with a clearance provided therebetween; and a plate spring comprising one end connected to a main shaft side of a driving source by a first connecting portion and another end connected to the armature plate by a second connecting portion, wherein an elastic force of the plate spring separates the armature plate from the rotor when the electromagnetic coil is in a deenergized state, and the armature plate is attracted to the rotor by magnetomotive force when the electromagnetic coil is energized, an angle formed between the plate spring and the armature plate is between 10° and 63°, and an extension direction of the plate spring extending from the one end of the plate spring toward the another end thereof intersects a tangent line at the armature plate and forms an obtuse angle with the tangent line on a side including the main shaft, and the extension direction of the plate spring intersects, at an acute angle, a connecting line direction extending from a center of the main shaft to a center of the second connecting portion, wherein the plate spring has an arcuate shape bending in a rotation direction of the armature plate from the another end of the plate spring to the one end of the plate spring.