Pinion shaft

Abstract

A pinion shaft (7) formed using a non-refined steel as a material comprises a shaft section (71, 72) and a pinion teeth forming section (70) connecting with the shaft section (71, 72). The pinion teeth forming section (70) comprises pinion teeth (7a) and a tooth bottom (7b). The pinion teeth forming section (70) and the shaft section (71, 72) are provided with a hardened layer (80) that has been subjected to induction hardening and tempering. The steel contains 0.45 to 0.55% by mass of C, 0.10 to 0.50% by mass of Si, 0.15 to 0.25% by mass of Mo, and 0.0005 to 0.005% by mass of B. The surface hardnesses of the pinion teeth forming section (70) and the shaft section (71, 72) are 650 to 760 HV in terms of Vickers hardness.

Dependencies are inferred from the claim text.