| 摘要 |
PURPOSE:To make it possible to release oil pressure from friction coupling element with a suitable speed according to kinds of speed change by branching off an oil passage of friction coupling element into two systems, and communicating one of two branched oil passages with a drain by a changeover means. CONSTITUTION:A line 121 of a 3-4 clutch 43 is branched off into two systems, one side line 121, 122 is only through an one-way orifice 76 and the other side line 123 is through a 2-3 accumulator, respectively connected to a 3-4 shift valve 65. Hereupon, the 3-4 shift valve 65 is operated with a third solenoid valve 68. Hereby, as the solenoid valve 68 is in the OFF condition on the way of speed change at 3 2 shift-down speed change, the line 121, 122 is communicated to a line 124, and the clutch pressure is quickly released to a drain. On the other hand, as the solenoid valve 68 is in the ON condition at 4 2 shift- down speed change, the line 123 is communicated to the line 124 and the clutch pressure is gradually released to the drain. |
