SPEED CHANGING APPARATUS FOR MOTOR VEHICLES

摘要

An automotive vehicle has an automatic transmission to which fluid is supplied from a source through a control valve having a body which is displaceable to control the flow of the fluid to the load constituted by this tranmission. A plurality of binarily stepped pilot faces are provided on one side of the valve body and the other side is connectable to the source of fluid pressure. A plurality of pressurizable chambers at each of the surfaces are each connected via a respective line to a respective solenoid valve itself connected to the high-pressure side of this system. Binary actuation of these pilot surfaces via the solenoid valves in accordance with motor speed allows the transmission very smoothly to be upshifted and downshifted.