Patent ID: 8052560
Filing Date: 2011-11-08
Classification: F16D,F16H

Abstract:
1. A power transmission device comprising: a pulley rotatably fitted to a housing; and a hub adapted to a distal end portion of a rotary shaft protruding outside from said housing, and rotating integrally with said rotary shaft, wherein: said hub includes an inner hub fixed to said rotary shaft and arranged inside a torque transmitting elastic member, an outer hub arranged outside said torque transmitting elastic member and interconnected to an end face of said pulley on the front side and said torque transmitting elastic member interposed between said inner hub and said outer hub and held by said inner and outer hubs, a hub side engagement portion formed of an elastic material such as rubber or a resin and disposed on either one, or both, of an inner peripheral surface side and an outer peripheral surface side of said outer hub and a pulley side engagement portion disposed at a position corresponding to said outer hub on the end face of said pulley on the front side engage with each other to thereby form a torque transmission structure between said hub and said pulley, said hub side engagement portion formed at a part of said torque transmitting elastic member and said pulley side engagement portion formed on said pulley fit to each other in concavo-convex engagement and form a concave-convex fitting portion, and a ring-shaped dust invasion prevention portion is so arranged as to cover a front surface of said concavo-convex fitting portion, said concave-convex fitting portion having concave portions formed on the pulley side engagement portion and depressed in the radial direction, and convex portions being formed on the hub side engagement portion and projecting in a radial direction, and said dust invasion prevention portion being formed to project in the radial direction outside from said hub side engagement portion of the torque transmitting elastic member.