Pinion bearing

A pinion bearing, comprising:

• two inner rings each having an orbital plane formed on an outer surface of corresponding inner ring;
• an outer ring positioned outside the two inner rings in a radial direction and having two rows of orbital planes formed on an inner surface of the outer ring;
• a plurality of rolling elements configured to rotatably support the inner ring relative to the outer ring;
• and
• sealing members configured to be provided on both axial end portions of a bearing space in which two rows of rolling elements are located and seal the bearing space,
• wherein a bearing space in which the two rows of rolling elements are located is filled with a grease to provide a lubrication,
• wherein the outer ring comprises a flange portion formed to extend outward in the radial direction, a first extension portion formed to extend from the flange portion in one axial direction, and a second extension portion formed to extend from the flange portion in another axial direction,
• wherein a plurality of heat dissipation fins is formed on the second extension portion to protrude outward in the radial direction and are provided to be spaced apart from each other along a circumferential direction of the pinion bearing, and
• wherein the outer ring is formed of a single member.