Patent ID: 9278387
Filing Date: 2016-03-08
CPC Classification: B21D,B24C,F16F

Claim Text:
1. A production method for a leaf spring having a leaf portion and an eye portion formed at the leaf portion, comprising steps of: forming a gap portion between a leading end portion of the eye portion and a facing portion facing the leading end portion; shot peening an inner surface of the eye portion by disposing a reflection member, which has a reflection surface, inside the eye portion, injecting shots from a nozzle to the reflection member, and projecting the shots, which are reflected by the reflection surface of the reflection member, to the inner surface of the eye portion, wherein in the shot peening, the reflection surface is located at a cross section perpendicular to an axial direction of the eye portion such that a straight line does not cross the leading end portion of the eye portion, the straight line connecting an intersection point and a center point of the reflection surface of the reflection member, the intersection point being between a perpendicular line and a surface of the facing portion, the perpendicular line extending from a leaf portion side end point of the leading end portion of the eye portion to the facing portion, whereby shots are projected to the entire surface of the facing portion.