Patent ID: 8152383

Claim:
A tapered roller bearing comprising: an inner ring; an outer ring; a plurality of tapered rollers rollably disposed between the inner ring and the outer ring; and a cage for holding the tapered rollers at predetermined circumferential intervals, wherein: a roller coefficient γ of the tapered roller bearing is greater than 0.94; at least one of the inner ring, the outer ring, and the tapered rollers has a nitrogen-rich layer, the nitrogen-rich layer having austenite crystal grains with a grain size number greater than 10; the inner ring has a cone back face rib having a surface including a conical surface in contact with large end faces of the tapered rollers and a flank that smoothly extends outwardly from the conical surface and is curved in a direction away from the large end faces of the tapered rollers; the cage includes a small annular portion continuous on a small end face side of the tapered rollers, a large annular portion continuous on a large end face side of the tapered rollers, and a plurality of bars connecting the small annular portion and the large annular portion; the cage has a plurality of trapezoidal pockets formed between adjacent ones of the bars, each of the trapezoidal pockets having a narrow side that receives a small diameter side of one of the tapered rollers and a wide side that receives a large diameter side of the one of the tapered rollers, and each of the bars having a cut-away portion on the narrow side of the trapezoidal pockets; and a width of the small annular portion of the cage adjacent to corner portions of the trapezoidal pockets is not narrower than a width of the small annular portion of the cage adjacent to a central portion of the narrow side of each of the trapezoidal pockets.