Patent ID: 6823974
Filing Date: 2004-11-30
Classification: F16D

Abstract:
An electromagnetic clutch comprising:an electromagnetic coil for generating an electromagnetic force when being energized; a drive-side rotation member rotated by a driving source; an armature attracted to said drive-side rotation member in response to the electromagnetic force generated by said electromagnetic coil to receive rotation of said drive-side rotation member; a driven-side rotation member connected to a driven-side device; and a spring means which couples said armature to said driven-side rotation member and supports said armature such that said armature is capable of being displaced toward said drive-side rotation member, wherein said spring means is a plate of polygonal leaf spring, said leaf spring comprising: an outer ring portion connected to said armature; an attachment portion positioned inside said outer ring portion and connected to said driven-side rotation member; a plurality of connecting portions between said outer ring portion and said attachment portion; a plurality of securing portions of said armature disposed in a circumferential direction of said outer ring portion; a plurality of first elastic members disposed at intermediate points of said plurality of securing portions in the circumferential direction of said outer ring portion to give an initial deflection to said leaf spring; and a second elastic member disposed between said leaf spring and said drive-side rotation member in an axial direction, wherein said second elastic member is elastically deformed between said leaf spring and said driven-side rotation member when the electromagnetic force generated by said electromagnetic coil displaces said armature toward said drive-side rotation member in an axial direction; and wherein said armature collides with said plurality of first elastic members to determine its axial position when said electromagnetic coil is unenergized and said armature is separated from said drive-side rotation member to return to an original position.