Hydraulic circuit for controlling automatic transmission

摘要

A hydraulic circuit for controlling an automatic transmission. The hydraulic circuit has a control valve connected between a shift valve and a hydraulic servomotor for actuating a frictional engagement element such as a brake in a main transmission unit. The control valve is controlled by a signal from a control means in such a manner that, when the hydraulic servomotor is drained by the operation of the shift valve to disengage the brake, the engagement of a frictional engaging element in another transmission unit is synchronized therewith.