Patent ID: 7993231

Claim:
A hydraulic control device for an automatic transmission, comprising: a first solenoid valve that supplies a first operating hydraulic pressure to a hydraulic servo of a first friction engagement element; a second solenoid valve that supplies a second operating hydraulic pressure to a hydraulic servo of a second friction engagement element; a third solenoid valve that supplies a third operating hydraulic pressure to a hydraulic servo of a third friction engagement element and is a normally open solenoid valve that outputs the third operating hydraulic pressure during non-energizing; a preliminary shift speed switching valve that switches to a low speed side position in order to output a first preliminary hydraulic pressure for the hydraulic servo of the first friction engagement element and a high speed side position in order to output a second preliminary hydraulic pressure for the hydraulic servo of the second friction engagement element based on an engaged state of the second friction engagement element; and a hydraulic pressure supply switching valve that switches to a normal position that supplies the first and second operating hydraulic pressures to the hydraulic servos of the first and second friction engagement elements, respectively, and a failure position that supplies the first and second preliminary hydraulic pressures to the hydraulic servos of the first and second friction engagement elements, respectively, at a failure resulting in non-energizing, wherein the second friction engagement element is engaged at high speed side shift speeds, a low speed that is one of low speed side shift speeds is achieved by engagement of the first friction engagement element and the third friction engagement element, and a high speed that is one of the high speed side shift speeds is achieved by engagement of the second friction engagement element and the third friction engagement element.