Patent ID: 7070034

Claim:
An electromagnetic clutch comprising: a first magnetic member with a large-diameter cylindrical portion made of a magnetic metal; a second magnetic member with a small-diameter cylindrical portion made of a magnetic metal and contained in said large-diameter cylindrical portion; an annular member of a non-magnetic material interposed between and joined to said large and small diameter cylindrical portions to constitute a magnetic path forming member having a clutch contact surface at a front end thereof; a friction clutch arranged between the clutch contact surface formed at the front end surface of said magnetic path forming member and an armature; an electromagnet arranged behind the magnetic path forming member for generating magnetic flux between said large and small-diameter cylindrical portions, wherein the inner diameter of said clutch contact surface at the front end portion of said large-diameter cylindrical portion and the outer diameter of said clutch contact surface at the front end portion of said small-diameter cylindrical portion are substantially the same respectively as the outer and inner diameters of said annular member; the outer and inner surfaces of said annular member are joined respectively to the internal surface of said large-diameter cylindrical portion and the outer surface of said small-diameter cylindrical portion with the front end surface of said annular member receding a predetermined distance from said clutch contact surface.