Toroidal-type continuously variable transmission

A continuously variable transmission, comprising:

• an input disk interlocking with an input shaft;
• an output disk interlocking with an output shaft;
• and
• a power roller bearing including an inner race, an outer race and a plurality of rolling elements, said inner race engaging with said input disk and said output disk to thereby transmit power of said input shaft to said output shaft;
• wherein at least one of components of said continuously variable transmission including said inner and said outer races of said power roller bearing, said input disk and said output disk is comprised of an alloy steel material comprising C:
• 0.15 to 0.5 wt %, Si:
• 0.1 to 1.5 wt %, Mn:
• 0.1 to 1.5 wt %, Cr:
• 0.5 to 3.0 wt %, and at least one kind selected from Mo:
• 0.1 to 3.0 wt % and V:
• 0.1 to 3.0 wt %, a content of O in said alloy steel material being set to be not more than 9 ppm,
• wherein the surface of said at least one of components after carbonitriding, hardening and tempering treatments is set to contain C:
• 0.8 to 1.2 wt % and N:
• 0.05 to 0.20 wt %,
• wherein said at least one of components has surface hardness of Hv 720 or more, and
• wherein Mo or V carbide/carbonitride, the average particle size of which is in a range of from 50 nm to 500 nm, is dispersed and precipitated on a race surface or in a range of from the race surface to a deep position where a maximum shearing stress is generated.