Development of High Durability Pinion-Shaft for Downsized Auto-Transmission

Abstract

The development of the material for pinion shaft in planetary gear set was performed to solve the durability problem of downsized auto-transmission. Resistance to softening of pinion shaft in hot environment was increased by adding Si and resistance to crack initiation due to dent was increased by adding Mn. As a result of this study, thrust rolling contact fatigue specimen with developed material showed increasing fatigue life and there was no flaking on the surface of pinion shaft after transmission durability test.