| 摘要 |
PROBLEM TO BE SOLVED: To reduce torque. SOLUTION: The angle (contact angleα) at which the raceway surface 1a of an outer ring 1 forms to a bearing central axis X is 21 to 25 degrees, and the ratio (thickness ratio PR=DA/W×100) of the average diameter (DA) of a conical roller 3 to the interval (W) between the inside diameter surface of an inner ring 2 and the outside diameter surface of the outer ring 1, on a cross section P perpendicular to the axis of the conical roller 3 and passing a center where the diameter of the conical roller 3 attains the average diameter (DA), is 40 to 51%. A roller factor (θ) represented asθ=(Z.DA)/(π.PCD) (Z: number of conical rollers 3, DA: average diameter of conical roller 3, PCD: pitch circle diameter of conical roller 3) is 0.86 to 0.94, and the ratio (=L/DA) of the length (L) to the average diameter (DA) of the conical roller 3 is set at 1.20 to 2.25.
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