Abstract: A power transmission system including an integrally molded hub and elastic member, where stress is inhibited from concentrating at the gate marks remaining after integral molding. In a pulley driven by a belt, a plastic pulley side relief section 1a provided at a pocket section of the pulley and a plastic hub side relief section provided on an iron outer ring of the hub engaged at the pocket section whereby power is transmitted from the pulley to the shaft. The hub side relief section and outer ring forming parts of the hub, the iron inner hub to be fastened to the shaft, and the plastic cylindrical part are integrally molded so that the gate mark for plastic injection is formed near to or further to the outer circumference of the outer ring.

Abstract: A bearing according to the present invention includes a cylindrical member formed on and around an outer member of a usual bearing. To firmly connect the cylindrical member to the outer member, grooves having an inclination relative to the axial direction of the bearing are formed so that the grooves do not cross one another on the outer surface of the outer member. The cylindrical member is made of a resin material by molding, and the resin, which is melted by heat in the molding process, enters into and adheres to the grooves. In this manner, the cylindrical member is firmly connected to the outer member so that movement in both of the rotational and axial directions of the bearing is prevented. The grooves formed on the outer surface of the outer member may be grouped, and their inclination relative to the axial direction may be alternately reversed group by group.

Abstract: A bearing according to the present invention includes a cylindrical member formed on and around an outer member of a usual bearing. To firmly connect the cylindrical member to the outer member, grooves having an inclination relative to the axial direction of the bearing are formed not to cross one another on the outer surface of the outer member. The cylindrical member is made of a resin material by molding, and the resin molten by heat in the molding process enters into and adheres to the grooves. In this manner, the cylindrical member is firmly connected to the outer member not to move in both of the rotational and axial directions of the bearing. The grooves formed on the outer surface of the outer member may be grouped, and their inclination relative to the axial direction may be alternately reversed group by group.

Abstract: A power transmission system including an integrally molded hub and elastic member, where stress is inhibited from concentrating at the gate marks remaining after integral molding. In a pulley driven by a belt, a plastic pulley side relief section 1a provided at a pocket section of the pulley and a plastic hub side relief section provided on an iron outer ring of the hub engaged at the pocket section whereby power is transmitted from the pulley to the shaft. The hub side relief section and outer ring forming parts of the hub, the iron inner hub to be fastened to the shaft, and the plastic cylindrical part are integrally molded so that the gate mark for plastic injection is formed near to or further to the outer circumference of the outer ring.