Patent ID: 7874737

Claim:
A tapered roller bearing comprising: an outer ring including a crowned raceway surface; an inner ring including a crowned raceway surface; a plurality of tapered rollers that include crowned rolling contact surfaces and are interposed between the outer ring and the inner ring; and a cage for the tapered rollers, wherein when an arithmetical mean roughness as a surface roughness of a large end face of the tapered roller is σ1 and an arithmetical mean roughness as a surface roughness of a large rib surface of the inner ring is σ2, σ1 is 0.04 μm or larger, a composite roughness that is expressed by a square root of a sum of a squared value of σ1 and a squared value of σ2 is 0.17 μm or smaller, a total crowning amount, which is a sum of outer ring crowning amount, inner ring crowning amount and two times of roller crowning amount, is 50 μm or larger, wherein the outer ring crowning amount is defined as CRO=RCO−(RCO 2 −(LRO/2) 2 ) 1/2 , wherein RCO is a radius of a crowning arc of the outer ring and LRO is a raceway length, wherein the roller crowning amount is defined as CR=RC−(RC 2 −(LWR/2) 2 ) 1/2 , wherein RC is a radius of a crowning arc of the roller and LWR is a roller effective length, and wherein the inner ring crowning amount is defined as CRI=RCI−(RCI 2 −(LRI/2) 2 ) 1/2 , where RCI is a radius of a crowning arc of the inner ring and LRI is a raceway length, an outer ring crowning rate, which is a rate of the outer ring crowning amount on the total crowning amount, is 40% or larger, and a roller crowning rate, which is a rate of two times of the roller crowning amount on the total crowning amount is 20% or smaller.