Automatic transmission for hybrid vehicle

An automatic transmission for a hybrid vehicle disposed on a transfer path between an internal combustion engine and wheels and controlled so as to be able to run idle in the case where a vehicle is driven by a rotary electric machine with the internal combustion engine stopped, comprising:

• a first hydraulic pressure supply source driven in conjunction with the internal combustion engine to produce a hydraulic pressure;
• a second hydraulic pressure supply source driven by electric power independently of the first hydraulic pressure supply source to produce a hydraulic pressure;
• a regulator valve that regulates the hydraulic pressure produced by the first hydraulic pressure supply source and the second hydraulic pressure supply source to a line pressure;
• a first oil passage through which the line pressure regulated by the regulator valve is supplied to a hydraulic servo for engagement and disengagement of a friction engagement element;
• a second oil passage through which a hydraulic pressure discharged from the regulator valve is supplied to a portion to be lubricated via an oil cooler;
• a third oil passage through which the hydraulic pressure produced by the second hydraulic pressure supply source is supplied to the portion to be lubricated, the third oil passage being merged with the second oil passage at a location downstream of the oil cooler;
• and
• a first reverse flow prevention mechanism disposed between the oil cooler and a merging point that the second oil passage and the third oil passage are merged to prevent reverse flow of a hydraulic pressure from the merging point to the oil cooler.