| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a wheel bearing device ensuring hardness and strength comparable to conventional refining product levels by enhancing strength and durability of a hub ring under rotationally bent conditions, while reducing its weight without changing the shape and size of a wheel mounting flange and without impairing its face deflection, and to provide its manufacturing method. <P>SOLUTION: After forging, controlled cooling of a hub ring 1 is performed such that it has a troostite texture or a sorbite texture, or the mixed texture of a troostite texture and a sorbite texture, and hardness of the hub ring 1 is set in a range of 23-35 HRC. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
