| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method in which the material flow of a nut blank is suppressed and bending stress acting on a punch is reduced when forming a ball circulating groove in the inner peripheral surface of the nut blank by forging machining method using the punch. <P>SOLUTION: First, a through hole (material lost part) 13 extending in a radial direction is formed at a position where the ball circulation groove 15 is formed in an axial direction to the cylindrical nut blank 1. The through hole 13 is formed along a S-shape ball moving direction of the ball circulation groove 15. Next, the ball circulation groove 15 is formed while making a material flee to the through hole 13 by the forging machining method using the punch at a position where the through hole 13 is formed of the inner peripheral surface of the nut blank 1. <P>COPYRIGHT: (C)2012,JPO&INPIT |
