| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a wheel bearing device for actualizing lower torque without lowering the rigidity of a bearing. <P>SOLUTION: The wheel bearing device comprises: an outward member having double row outer races 44 on the inner periphery; an inward member having double row inner races 34 on the outer periphery; tapered rollers 46 rollingly laid between the outer race 44 and the inner race 34; and a cage 48 for holding the tapered rollers 46 in rows at predetermined circumferential spaces. A roller coefficientγis over 0.94. A number of finely recessed cavities are randomly provided in the surfaces of at least the tapered rollers 46, and a surface roughness parameter Ryni of each of the surfaces in which the cavities are provided is in a range of 0.4μm≤Ryni≤1.0μm, and the upper limit of a Sk value is -1.6. The cage 48 consists of: a small annular portion ranging over the tapered rollers 46 at their small end face sides; a large annular portion ranging over the tapered rollers 46 at their end face sides; and a plurality of columnar portions connecting these annular portions to each other. Between the adjacent columnar portions, trapezoidal pockets are formed so that their porions storing the tapered rollers 46 on their small diameter sides are located on the narrow sides, and their portions storing them on their large diameter sides are located on the wide sides. Cutouts are provided in the columnar portions on the narrow sides. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
