| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve a practical structure capable of being constituted at low cost and not requiring strict dimension control so as to easily control dimension for allowing sure separation. <P>SOLUTION: A part which is radially recessed like a reduced diameter part 15 is provided over the entire periphery of either an outer periphery surface closer to axially inner ends of both first and second inner shafts 8a, 9a or an end part inner periphery surface of a first outer tube 10a at a side of a second outer tube 11a. At the radially recessed part, a cyclic gap 16 in which the radially recessed part does not get in contact with an opponent periphery is interposed over the entire periphery. Further, the axially inner end surfaces of the first and second outer tubes 10a, 11a are mutually confronted, and the first inner shaft 8a is tucked in the second outer tube 11a among them. In the state above, the confronted part of the axially inner ends surfaces of the outer tubes 10a, 11a is positioned to be radially outside of the cyclic gap 16. <P>COPYRIGHT: (C)2009,JPO&INPIT |
