HYDRAULIC CONTROL DEVICE FOR AUTOMATIC TRANSMISSION

PROBLEM TO BE SOLVED: To provide a hydraulic control device for an automatic transmission, which makes it possible to individually supply hydraulic pressure to, and release hydraulic pressure from, two hydraulic oil chambers and to reduce the number of solenoid valves, thereby permitting cost reduction and enabling the device to be made compact. SOLUTION: This hydraulic control device includes a first B-2 relay valve 24 changing over supply and discharge of hydraulic pressure to and from an inner oil chamber 45A, and a second B-2 relay valve 25 changing over supply and discharge of hydraulic pressure to and from an outer oil chamber 45B, is constructed to supply signal pressure PS2of a solenoid valve S2 to an oil chamber 24a, an oil chamber 25a, and an oil chamber 25e, and changes over an input state of the signal pressure PS2to the oil chamber 25e by a C-2 supply relay valve 23 to be changed over by signal pressure PS1of a solenoid valve S1 for fail safe. It becomes possible to individually make a changeover of the first B-2 relay valve 24 by the solenoid valve S2 and a changeover of the second B-2 relay valve 25 by the solenoid valve S1. COPYRIGHT: (C)2011,JPO&INPIT