Patent ID: 7175556

Claim:
A hydraulic control apparatus for an automatic transmission, which is mounted in a vehicle, which includes multiple friction engaging elements each of which is engaged by being supplied with hydraulic pressure, and in which less than a half of the multiple friction engaging elements are engaged by being supplied with hydraulic pressure and the friction engaging elements other than the friction engaging elements that are supplied with the hydraulic pressure are disengaged, whereby at least one of multiple shift speeds is achieved, comprising: normal closed type electromagnetic valves which are provided so as to correspond to the friction engaging elements such that hydraulic pressure is supplied to the friction engaging elements; an oil pump which generates hydraulic pressure to be supplied to the electromagnetic valves and the friction engaging elements; a first oil passage which is connected to the electromagnetic valve that is energized when a predetermined shift speed is achieved from among the multiple electromagnetic valves; a second oil passage which is connected to the oil pump and which is different from the first oil passage; and a switching device which connects the first oil passage to the friction engaging element and disconnects the second oil passage from the friction engaging element when the electromagnetic valves can be energized, and which disconnects the first oil passage from the friction engaging element and connects the second oil passage to the friction engaging element when the electromagnetic valves cannot be energized.