Patent ID: 7435008

Claim:
A vehicle pinion shaft support system comprising: a pinion shaft; and a tapered roller bearing which supports the pinion shaft and has an inner race, an outer race, and tapered rollers, wherein the inner race has a large rib face having a recessed surface shape on which large-diameter end faces of the tapered rollers slide, such that, when a surface roughness of the large-diameter end faces is σ 1 μmRa and a surface roughness of the large rib face is σ 2 μmRa, σ 1 ≧0.025 μmRa and (σ 1 2 +σ 2 2 ) 1/2 ≦0.17 μmRa, wherein sliding portions of the large-diameter end faces of the tapered rollers which slide on the large rib face and a sliding portion of the large rib face of the inner race on which the large-diameter end faces of the tapered rollers slide comprise carburized steel, and wherein the sliding portions are set such that a carbon content in a matrix phase in a surface layer portion of each of the sliding portions from a depth of 50 μm to a surface thereof is 0.8 wt % or more, and a surface retained austenite amount is in a range of 20% to 25%.