Vehicle pinion shaft support system

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, and when assuming that the surface roughness of the large-diameter end faces is σ1 [μmRa] and the surface roughness of the large rib face is σ2 [μmRa], σ1 is 0.025 or more and (σ12+σ22)1/2 is 0.17 [μmRa] or less, wherein
• a sliding portion of the large-diameter end face of the tapered roller which slides on the large rib face and a sliding portion of the large rib face of the inner race on which the large diameter end face of the tapered roller slides are made by applying a heat treatment including a carburizing treatment to a steel material including 0.15 to 0.3 wt % carbon, wherein
• in a portion of each of the sliding portions to a depth of 50 μm from a topmost surface thereof as a base, the carbon content is in the range of 1.0 to 1.5 wt %, the Rockwell hardness in scale C is in the range of 64 to 66, the compression retained stress is in the range of 150 to 2000 MPa, the maximum carbide diameter is 3 μm or less and the carbide area ratio is in the range of 10 to 25%, and wherein
• in a portion of each of the sliding portions to a depth of 50 to a/5 μm when assuming that an effective hardened layer dept is a [μm], the carbon content is in the range of 0.75 to 1.3 wt %, the compression retained stress is in the range of 150 to 1000 MPa, the retained austenite amount is in the range of 25 to 45%, the maximum carbide diameter is 1 μm or less and the carbide area ratio is 15% or less.

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, and when assuming that the surface roughness of the large-diameter end faces is σ1 [μmRa] and the surface roughness of the large rib face is σ2 [μmRa], σ1 is 0.025 or more and (σ12+σ22)1/2 is 0.17 [μmRa] or less, wherein
• a sliding portion of the large-diameter end face of the tapered roller which slides on the large rib face and a sliding portion of the large rib face of the inner race on which the large diameter end face of the tapered roller slides are formed by forming a carbonitride or nitride in a surface portion by carbonitriding or nitriding a high carbon steel material, quenching a substrate of the surface portion from an inside thereof as high carbon or high nitrogen, and thereafter annealing the same at a temperature in the range of 200 to 250° C.

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, and when assuming that the surface roughness of the large-diameter end faces is σ1 [μmRa] and the surface roughness of the large rib face is σ2 [μmRa], σ1 is 0.025 or more and (σ12+σ22)1/2 is 0.17 [μmRa] or less, wherein
• a sliding portion of the large-diameter end face of the tapered roller which slides on the large rib face and a sliding portion of the large rib face of the inner race on which the large diameter end face of the tapered roller slides are formed by forming a carbonitride or nitride in a surface portion by carbonitriding or nitriding a high carbon steel material, quenching a substrate of the surface portion from an inside thereof as high carbon or high nitrogen, applying a sub-zero treatment to the substrate so quenched, and thereafter annealing the same at a temperature in the range of 150 to 200° C.