| 摘要 |
PROBLEM TO BE SOLVED: To provide a wheel bearing device realizing an enhancement in strength and durability while solving such contradictory problems of materializing a weight reduction, compactification and high rigidity of the device. SOLUTION: In the wheel bearing device with a third generation structure including double-row rolling element rows and fixing an inner ring 6 thereto by rockingly caulking an end of small-diameter step part 13b of a hub wheel 13, a pitch circle diameter PCDo of the rolling element row on the outer side of the double-row rolling element rows is set smaller than a pitch circle diameter PCDi of the rolling element row on the inner side. The rolling element row on the outer side is made up of balls 9. The rolling element row on the inner side is made up of conical rollers 10. The number of balls 9 are set more than that of conical rollers 10. By so doing, the enhanced bearing rigidity and reduced torque can be both realized. As a result, the service life can be the same as or longer than even when a load applied to the bearing row on the inner side becomes larger than that on the outer side. COPYRIGHT: (C)2008,JPO&INPIT
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