METHOD FOR MANUFACTURING PRECISE RESIN PRODUCT, AND SEAL FOR BEARING

摘要

PROBLEM TO BE SOLVED: To provide a seal for a bearing capable of preventing the fall off of the gate mark remaining after injection molding due to a pinpoint gate system. SOLUTION: The seal 20 for the bearing is constituted so that the seal piece 21 provided to the outer periphery of the seal 20 is locked with the inner peripheral surface of the outer race 3 of the bearing to be mounted on the annular open part 4 between the inner race 2 and outer race 3 of the bearing 1. This seal 20 is constituted of an annular molded article obtained by injection molding due to the pinpoint gate system, for injecting a thermoplastic resin molding compound 30 in the cavity 53 of a mold 50 through a pinpoint gate 60. The gate mark 25 is crushed and molded by the horn 71 of an ultrasonic welder 70 to be reduced in its height.