| 摘要 |
<p>A sleeve is fitted on a male yoke, and an opening on the opposite side of that portion of the sleeve where the male yoke is connected is sealed by a first lid member. A through-hole is formed in the male yoke, and the through-hole has a circular hollow first path and a circular hollow second path that is on the first lid member side of the first path and having an inner diameter less than that of the first path. Also, a second lid member is placed so as to close that opening in the through-hole that is on the opposite side of the first lid member. An air vent hole is formed in the second lid member so as to partially axially overlap with the inner peripheral surface of the first path and extend in the axial direction.</p> |
