Ultrasonic blow processing method of ultrasonic blow processing apparatus and coil spring coil spring

摘要

PROBLEM TO BE SOLVED: To provide a method of ultrasonic impact processing for a coil spring, reducing processing time while uniformly applying compressive residual stress on an inner circumferential surface of a coil spring and capable of achieving improvement in fatigue characteristics of the coil spring.;SOLUTION: In the method of ultrasonic impact processing for a coil spring, a rod-like impact tool 2, which is constituted such that an outer circumferential surface 2a thereof is brought into contact with an inner circumferential surface 4b of a coil spring 4 or the outer circumferential surface 2a is separated from the coil inner circumferential surface 4b with a gap therebetween, is inserted into an coil inside 4a of the coil spring 4, and ultrasonic vibration is applied to the impact tool 2 so that the entire surface of the coil inner circumferential surface 4b is impacted by the outer circumferential surface 2a.;COPYRIGHT: (C)2012,JPO&INPIT