Hydraulic control device of transmission

摘要

A hydraulic control device of a power transmission train having a torque converter which is selectively driven either mechanically or hydraulically. The device includes a transmission composed of clutch brakes and gear sets, and has a valve for hydraulically controlling the clutch brakes when the torque converter is driven mechanically. The torque converter is driven hydraulically when the power transmission train is started so that it requires a large driving force and the torque converter is driven mechanically when the power transmission train is driven at high speed to reduce the power loss.