Patent attributes
A hydraulic pressure supply system of an automatic transmission for a vehicle may include a low-pressure hydraulic pump, a low-pressure regulator valve, a high-pressure hydraulic pump, a high-pressure regulator valve regulating the high hydraulic pressure supplied from the high-pressure hydraulic pump to be stable hydraulic pressure and supplying the regulated hydraulic pressure to the high pressure portion, a first switch valve disposed between the low-pressure hydraulic pump and the low-pressure regulator valve, and selectively communicating the low-pressure hydraulic pump to the low-pressure regulator valve, a second switch valve selectively opening or closing a first circulating line connecting a downstream of the low-pressure hydraulic pump to an upstream of the high-pressure regulator valve, and a third switch valve selectively opening or closing a second circulating line connecting a downstream of the high-pressure regulator valve to an upstream of the low-pressure regulator valve.
