Transmission fluid pressure control device with two stepped line pressures

摘要

A hydraulic fluid pressure control system for a transmission which is shifted between two speed stages via a hydraulic actuator. A line pressure regulation valve receives supply of fluid pressure from a pump and produces a regulated line pressure. A switching valve receives supply of this regulated line pressure and selectively supplies it as an operating pressure to the fluid actuator, according to the opening and closing of a pilot port. This operating pressure is also supplied to the line pressure regulation valve for increasing the regulated value of the line pressure when the fluid actuator is being operated.