GEAR WITH LONG DEDENDUM LIFE AND CONTACT FATIGUE LIFE, AND MANUFACTURING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To prolong the pitting fatigue life of automotive parts and the like, which are shot peened in order to prolong the dedendum fatigue life, because load surface pressure against a gear is increased along with recent miniaturization, weight reduction, and output power increase. SOLUTION: The gear with the long dedendum life and the contact fatigue life is characterized by including certain contents of components such as Cr and Mo, and having a compressive residual stress of 400 MPa or more on the surface, an incompletely quenched layer of 3 m or thicker but 15 m or thinner, coefficient of friction of 0.02 or more but 0.05 or less on the surface, and residual austenite of 10% or less.