| 摘要 |
PROBLEM TO BE SOLVED: To prevent shift shock by preventing rapid pressure fluctuation from generated in an oil pressure chamber such as a clutch, when a solenoid valve or an electric system breaks down. SOLUTION: When a clutch is in a released state, an on/off solenoid valve 11 is in the closed state and a spool 19 is in a position toward the left side from a position illustrated in a figure so that a drain (D) and a communicating path 21 are in a communicated state. When the on/off solenoid valve 11 is switched to an open state, the spool 5 moves from the position illustrated in the figure to the right direction due to lowering of the pressure of a pressure chamber 7 and a pressure supply path 8 and input ports 12, 13 are communicated with each other so that a clutch pressure of an oil pressure chamber of a clutch 1 increases by enhancing its pressure gradient. Secondarily, the pressure of the communicating path 21 gradually increases, the spool 19 moves to the position illustrated in the figure and a flow path passing through notches 17, 18 is throttled so that the clutch pressure increases slowly. When the clutch pressure increases, the spool 19 moves further in the right direction, the input port 13 and the communication path 21 are communicated with each other, and a pressure increases gradient is enlarged again. |
