HYDRAULIC PRESSURE CONTROL SYSTEM OF AUTOMATIC TRANSMISSION FOR CAR

摘要

PURPOSE: A hydraulic pressure control system of an automatic transmission for a car is provided to perfectly realize asynchronous control by a one-way clutch, to rapidly respond during shift, and to improve a continued ratio by realizing hydraulic control of a first friction element by a solenoid valve. CONSTITUTION: A hydraulic pressure control system of an automatic transmission for a car includes first to third clutches(C1,C2,C3), and first and second brakes(B1,B2). Pressure controlled by a solenoid valve(S1) is hold in common for control of the fourth clutch and changed by a first switch valve(104). Pressure controlled by another solenoid valve(S2) is hold in common for control of the first brake, and changed by a second switch valve(108). Pressure controlled by another solenoid valve(S3) is hold in common for control of the second brake.