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US 2002/0170795 A1Published application
Electromagnetic clutch and rotation transmission device
AssigneeNtn Corporation
InventorsMakoto Yasui, Koji Sato, Yoshitaka Nagano
Life of this patent
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AssigneeNtn Corporation
InventorsMakoto Yasui, Koji Sato, Yoshitaka Nagano
Estimating the term…
The magnetic attraction force of an electromagnetic coil in an electromagnetic clutch is increased in a limited installation space, thereby improving reliability of operation. The dimensions of a field core housing the electromagnetic coil is coil and a rotor are optimized to increase the magnetic attraction force. The thicknesses of cylindrical portions on the inner-diameter side of the field core and the rotor have larger thicknesses than that of cylindrical portions on its outer-diameter side so that the sectional areas of both cylindrical portions will be equal to each other. Also, a rotation transmission device provided with an electromagnetic clutch is proposed which can prevent deterioration of sealing property and damage to the bearing and avoid cost increase.
An electromagnetic clutch comprising an inner member, an outer member rotatably and concentrically mounted around said inner member, a retainer mounted between said inner member and said outer member, engaging elements retained by said retainer, an armature arranged at one end of said retainer so as to rotate together with said retainer, a field core fixedly mounted, an electromagnetic coil mounted in said field core, and a rotor fixed to one of said outer member and said inner member for attracting and releasing said armature by energizing and deenergizing said electromagnetic coil, wherein said field core and said rotor each have cylindrical portions on inner and outer peripheral sides thereof and the cylindrical portion on the inner peripheral side has a larger thickness than that of the cylindrical portion on the outer peripheral side, whereby making uniform the magnetic flux density distributions of said field core and said rotor.
A rotation transmission device comprising an inner member, an outer member mounted so as to be concentric with said inner member, a housing for supporting said inner member or said outer member through a bearing, a retainer mounted in an annular space formed between said outer member and said inner member and formed with a plurality of pockets in a circumferential direction, engaging elements mounted in said pockets formed in said retainer, and an electromagnetic clutch for engaging and disengaging said engaging elements with said inner member and said outer member by changing the phase of said retainer relative to said inner member or said outer member, wherein a sealing device for preventing entry of foreign matter is provided between said housing and at least one of said inner member and said outer member, said sealing device being recessed from an end face of said housing.
Dependencies are inferred from the claim text.