Patent ID: 7798302

Claim:
An electromagnetic clutch for transmitting a turning force of a first rotor rotated by a power from outside to a rotational axle of a driven device, the electromagnetic clutch comprising: an armature plate arranged oppositely to the first rotor in the axial direction; an electromagnetic coil for attracting the armature plate to the first rotor side; a second rotor for transmitting the turning force transmitted from the armature plate side to the rotational axle of the driven device; a plate spring in which one end side is connected to the second rotor and the other end side is connected to the armature plate, and the plate spring having a strip-shaped part extending between a first connected part at said one end side and a second connected part at said other end side, the length of the strip-shaped part in the extending direction is greater than the width of the strip-shaped part in a direction perpendicular to the extending direction, the strip-shaped part comprises a wide portion located at a middle of the strip-shaped part in the extending direction; and an inclined portion configured by bending said wide portion of the strip-shaped part toward the electromagnetic coil to form a first bent portion and by bending a narrow portion of the strip-shaped part away from the electromagnetic coil to form a second bent portion, wherein said narrow portion is located at a radially outer position relative to said wide portion and a first axial distance between the first bent portion and the electromagnetic coil is greater than a second axial distance between the second bent portion and the electromagnetic coil, wherein the narrow portion is less than the wide portion in the perpendicular direction, and wherein the first bent portion has a concave shape with respect to the electromagnetic coil and the second bent portion has a convex shape with respect to the electromagnetic coil.