| 摘要 |
PURPOSE:To prevent speed change shock without lengthening speed change time by providing a control means to gradually lock an one-way clutch, at speed change from a first stage to a second stage. CONSTITUTION:At 4 2 shift-down, a by-pass line 155 is opened at the beginning when clutch pressure of a 3-4 clutch 43 starts to release due to OFF condition of a 5th solenoid valve 104, and the clutch pressure is relatively quickly released through a 2-3 shift valve 64 without suffering restrictive action of a fixed orifice 78. Consequently, speed change time at 4 2 shift-down can be shortened. When a turbine rotating speed becomes over the target rotating speed, the solenoid valve 104 becomes ON-condition and the clutch pressure is gradually released, due to the oil pressure maintaining action of an accumulator 80 and the restric tive action of a fixed orifice 78. Therefore, as an one-way clutch gradually changes from a free condition to a lock condition, speed change shock can be prevented. |
