| 摘要 |
<p>PURPOSE:To smooth return motion of a piston, by a method wherein a check valve, which allows a flow in a direction extending from a second chamber to a feed oil passage, is disposed in a drain passage through which a second chamber formed in a cylinder and the feed oil passage are intercommunicated. CONSTITUTION:When a frictional engaging device 32 is released from a frictionally-engaged condition, a working oil pressure in a feed oil passage 42 is brought into a pressure drainage state. In which case, drainage of the working oil pressure in a first chamber 16 is effected through feed oil passages 44 and 42, and a working oil pressure in a second chamber 18 is also discharged through a drain passage 22 directly to the feed oil passage 42. Namely, the working oil pressures in the first chamber 16 and the second chamber 18 are simultaneously drained. This enables the working pressure in the second chamber 18 to be rapidly drained as compared with a conventional process in which drainage is effected only through a communicating passage 20.</p> |
