Method for controlling hydraulic pressure of an automatic transmission for vehicles

摘要

A hydraulic control system of an automatic transmission for a vehicle includes a line pressure control part for converting line pressure from a hydraulic pump (2) into constant hydraulic pressure. A torque pressure generating part (20) converts the constant hydraulic pressure fed from the line pressure control part (8) via a manual valve (22) into torque pressure in accordance with the operation of a transmission control unit. A torque pressure switching part (26) switches the supply direction of the torque pressure fed from the torque pressure generating parts in accordance with the operation of the transmission control unit. A shift part (34) primarily feeds the torque pressure fed from the torque pressure switching part to friction members and secondly feeds drive pressure to the friction members after converting the line pressure fed from the line pressure control means into drive pressure.