| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw nut which suppresses a grain boundary oxidation zone produced during heat treatment and offers excellent durability, and a manufacturing method therefor. SOLUTION: In a manufacturing method of a ball screw nut, a ball rolling groove on which a ball rolls is helically formed in the inner peripheral surface. The method is provided with a process (P1) for drilling a specific inner diameter surface at the center of a material while forming the ball screw nut of a medium carbon carburizing steel containing 0.30-0.35 wt.% carbon, a process (P2) for finishing an outer peripheral surface and inner peripheral surface of the material by a bite, a process (P3) for inserting a tapping tool into the inner peripheral surface and cutting a ball rolling groove, and a heat treatment process (P4) for carburizing and quenching the ball rolling groove. By so doing, reduction in the heat treatment time for carburizing and quenching and suppression of a grain boundary oxidation zone produced on the surface are achieved. As a result, the ball screw nut which suppresses abrasion and peeling to offer excellent durability can be provided. COPYRIGHT: (C)2007,JPO&INPIT
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