| 摘要 |
PURPOSE:To make the high-speed characteristic smooth, by reducing the servo pressure of a hydraulic servo to a prescribed pressure by means of a release control valve, when the release of the hydraulic servo is carried out by a shift lever. CONSTITUTION:Between a shift valve 53 and a hydraulic servo Bo controlling a friction engaging element, a release control valve 66 which is controlled by the signal from a duty-controlled solenoid valve SD is provided, and in the oil passage y7 connecting the hydraulic servo Bo and an accumulator BoA, a check valve 73 which allows the flow from the hydraulic servo Bo to the accumulator BoA is provided. Thus, when the hydraulic servo Bo is released, the servo pressure of the hydraulic servo Bo is reduced to a prescribed pressure by means of a release control valve 66, and accordingly the release pressure of the hydraulic servo Bo can be properly controlled, enabling the change of speed to be smoothly carried out. |
