HYDRAULIC PRESSURE CONTROL DEVICE FOR AUTOMATIC TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic pressure control device for an automatic transmission in which a lockup clutch is released at the time of failure. SOLUTION: An output port e of a solenoid valve SOL1 is connected to a port 81f of a lockup control valve 81 and a port 79f of a garage shift valve 79. An output port f of a solenoid valve SOL2 is connected to a port 81g of the lockup control valve 81 and a port 79c of the garage shift valve 79. For the solenoid valves SOL1 and SOL2, at least one of them is provided to be duty-controllable. Out of combinations of signal pressures regulated by the solenoid valves SOL1 and SOL2, a pattern is used in which normal control can be performed to the automatic transmission normally, and in which the lockup clutch will not be changed from the released state into an engaged state at the time of failure.