| 摘要 |
PURPOSE:To prohibit a downshift change to a lower gear for the use of a one-way clutch as a reaction brake in a high engine speed range where the engagement shock of the one-way clutch becomes a problem. CONSTITUTION:When the second gear selection pressure P2 is caused to occur with a controller 17 via a solenoid 17, a valve 11 raises the operation pressure PB of a band brake B/B, and a shock for transition from the first gear to the second gear is alleviated. Upon disappearance of the pressure P2, the pressure PB is quickly released through a non-return valve 16, thereby ensuring high response to a downshift change to the first gear. In this case, when engine speed Ne is high, a low one-way clutch acting as a reaction brake at the first gear generates an engagement shock. The controller 17, therefore, prohibits the disappearance of the pressure P2 and consequently a downshift change to the first gear. |
