| 摘要 |
PURPOSE: A hydraulic controlling system of a CVT(continuously variable transmission) is provided to drive a vehicle in specific transmission/torque ratios by controlling the transmission ratio to an intermediate value between the maximum points and minimum points value in a fail of a TCU(transmission control unit). CONSTITUTION: In a fail of a TCU, a solenoid valve(S) is turned off and a valve spool(45) of a fail-safe valve(7) moves to left. A transmission ratio controlling valve(5) feeds hydraulic pressure to a driving pulley(11) through a first port(29) of the fail-safe valve(7) to fix a transmission ratio. A manual valve(3) supplies line pressure to a reverse brake(25) normally through fourth to sixth ports(35,37,39). Thus, a vehicle is backed up.
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