HYDRAULIC CONTROL SYSTEM OF 7-SHIFT AUTOMATIC TRANSMISSION FOR VEHICLES

摘要

A hydraulic control system for an automatic transmission of vehicles is provided to actively control the hydraulic pressure which is released form a frictional element, when R range is shifted to N range. A hydraulic control system supplies reverse pressure to a frictional element from a manual shift control unit(10) and supplies line pressure to a frictional element which operates with the frictional element under control of a shaft control unit(12), at reverse shift. A reverse pressure controlling member is manually controlled, when a working pressure is supplied into a pipe(20) connecting the manual shift control unit with the frictional element, while is electronically and manually controlled when the working pressure is released.