Hydraulic control device

A hydraulic control device for a speed change device capable of transferring power applied to an input member to an output member at a speed change ratio that is changeable in a plurality of stages by engaging and disengaging a plurality of hydraulic friction engagement elements, the hydraulic control device comprising:

• a first pressure regulation valve that regulates a hydraulic pressure to be supplied to a first hydraulic friction engagement element;
• a second pressure regulation valve that regulates a hydraulic pressure to be supplied to a second hydraulic friction engagement element;
• a line pressure generation valve that regulates a hydraulic pressure from a hydraulic pressure generation source to generate a line pressure;
• and
• a switching valve that can establish a first supply state, in which the hydraulic pressure from the first pressure regulation valve can be supplied to the first hydraulic friction engagement element when the first pressure regulation valve is normal, and that can establish a second supply state, in which the line pressure from the line pressure generation valve can be supplied to the first hydraulic friction engagement element during an abnormality in which a hydraulic pressure is not supplied from the first pressure regulation valve as normal, wherein
• the switching valve is selectively supplied with a first hydraulic pressure and a second hydraulic pressure that is lower than the first hydraulic pressure as a holding pressure, and supplied with the second hydraulic pressure as the holding pressure and supplied with the hydraulic pressure from the second pressure regulation valve during the abnormality, and
• the switching valve establishes the first supply state, irrespective of presence or absence of the hydraulic pressure from the second pressure regulation valve, when the first hydraulic pressure is supplied as the holding pressure, establishes the first supply state when the second hydraulic pressure is supplied as the holding pressure and the hydraulic pressure from the second pressure regulation valve is not supplied, and establishes the second supply state when the second hydraulic pressure is supplied as the holding pressure and the hydraulic pressure from the second pressure regulation valve is supplied.