Is superior in convolution fatigue strength through the rolling element null lube

摘要

PROBLEM TO BE SOLVED: To provide excellent pitching resistance and a rolling fatigue strength, almost prevent the occurrence of the crack and peel due to an inside factor, and provide an increased life by using a specified steel for machine structure use containing Cr, as a material for a rolling body. ;SOLUTION: A steel for machine structure containing Cr is used for the material of an input disc 5, an output disc 9, and a power roller 10, being a rolling body made of a metal, and, through carbonitriding treatment, it is preferable to get N amount of a rolling surface being 0.2-0.6wt.%, C+N amount in a position of a depth of d≤0.2Zst being 0.9-1.3wt.%, a residual austenite amount 20-45vol.%, and hardness being HV500 or more where Zst is the generating depth of a maximum shearing stress occurring at the interior of a rolling body due to surface contact and in a depth position being of 0.5Zst≤d≤1.4Zst, a C and N amount being 0.6≤C+N≤d≤1.2wt.%, and hardness being HV700 or more.;COPYRIGHT: (C)1997,JPO