| 摘要 |
PROBLEM TO BE SOLVED: To provide a toroidal type continuously variable transmission high in durability and long in longevity. SOLUTION: A least one of an inner ring 10, an outer ring 13, an input disc 2 and an output disc 3 of a power roller bearing 11 on a toroidal type continuously variable transmission 20 is constituted of a steel material selectively containing at least one kind of C=0.15-0.5%, Si=0.1-1.5%, Mn=0.1-1.5%, Cr=0.5-3.0%, and Mo=0.1-3.0%, V=0.1-3.0% in alloy component in weight percentage, of oxygen <= 9 ppm, a surface C, N% after carbonitriding, hardening and tempering processes satisfying specific values of surface C=0.8-1.2%, surface N=0.05-0.20% in weight percentage, surface hardness of which satisfies not less than Hv 720 and which disperses and deposits Mo and V carbide, carbonitride of an average grain diameter 50-500 nm at a lace surface or at a position of the maximum chearing stress generating depth from the lace surface.
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