A LINE PRESSURE ADJUSTMENT DEVICE OF AN AUTOMATIC TRANSMISSION VEHICLE

摘要

A line pressure regulating device of an automatic transmission vehicle is provided to improve durable performance and safety by preventing line pressure from being increased excessively if a hydraulic control system is operated wrongly for a forward level. A line pressure regulating device of an automatic transmission vehicle has a double-line relief valve(200) of which the opening pressure is regulated differently for a forward level(PFWD) and a reverse level(PREV) to prevent the increase of line pressure, although a hydraulic control system is operated abnormally in moving forward the vehicle. A hydraulic circuit for supplying line pressure for the forward or reverse level is disposed at one port of the double-line relief valve and a hydraulic circuit for feeding line pressure for the reverse level is installed at the other port of the relief valve.