| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To restrain settling of an O-ring 18 while restraining increase of costs, realize a structure capable of securing a sealing performance of the O-ring 18 for a long time, and realize a structure capable of preventing swelling of the O-ring 18 when needed, and easily recognizing a fact that the O-ring 18 is protruded from a predetermined portion due to swelling. <P>SOLUTION: The O-ring 18 is made of hydrogenation nitrile rubber, and has cross-sectional diameter of 1.4 mm or less and crushing ratio of 15-45%. Oil of a same kind as base oil of grease filled in a bearing space 11 is applied to a portion of a cap 6, to which the O-ring 18 is mounted. Furthermore, color on a surface of the O-ring 18 is other than black, which is a color of the surface of the cap 6. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
