| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent a seal lip from being affected by minute amplitude vibration caused by pressure fluctuation, mounting eccentricity of a cancel plate, or an offset load of a return spring, so as to extend the service life of an inner peripheral seal, in which the seal lip of the inner peripheral seal part is disposed to an inner peripheral end part of the cancel plate of a BPS (piston for automatic transmission). <P>SOLUTION: The BPS 1 has: a piston member 20 displacing inside of a cylinder 10 in an axial direction and defining a pressure chamber M together with the cylinder 10; and the cancel plate 30 opposed to a bottom part 11 of the cylinder 10 across the piston member 20. The inner peripheral seal part 50 has: the seal lip 52 in slidably close-contact with an inner peripheral cylinder part 13 of the cylinder 10; and a fitted part 53 fitted in the inner peripheral cylinder part 13, and the inner peripheral seal part 50 is disposed to an inner peripheral end part 35 of the cancel plate 30. <P>COPYRIGHT: (C)2009,JPO&INPIT |
