Hydraulic control device

A hydraulic control device which controls hydraulic pressure supplied to an automatic tan automatic transmission provided with a fluid coupling that has a lockup clutch, the hydraulic control device comprising:

• a pressure regulation valve configured to regulate a hydraulic pressure of oil supplied from an oil pump and supply the oil to the fluid coupling;
• a discharge oil passage through which the oil discharged from the fluid coupling flows when the lockup clutch is disengaged;
• a lubrication oil passage that supplies the oil from the discharge oil passage to a location to be lubricated in the automatic transmission;
• a return oil passage that returns the oil drained from the pressure regulation valve during pressure regulation to a suction port of the oil pump;
• a connection oil passage that connects the lubrication oil passage and the return oil passage;
• and
• a flow direction regulation valve that is provided in the connection oil passage, and that allows communication between the lubrication oil passage and the return oil passage when hydraulic pressure on the return oil passage side is higher than hydraulic pressure on the lubrication oil passage side by a pressure that is equal to or higher than a set differential pressure, and blocks communication between the lubrication oil passage and the return oil passage when differential pressure between hydraulic pressure on the return oil passage side and hydraulic pressure on the lubrication oil passage side is lower than the set differential pressure.