1/2-way control valve for an automatic transmission

摘要

The control valve functions in response to a control pressure, which counteracts a throttle valve pressure, and in response to a holding pressure, which is used in a kick-down process. The valve can be switched up from a first speed range into a second speed range and switched down from the second speed into the first speed, controlled by the control valve. The 1/2-way control valve comprises a spindle with a pressure absorption surface which can absorb either the throttle valve pressure or the holding pressure. In the first speed position the spindle shuts off the holding line pressure and receives the throttle valve pressure on the pressure absorption surface. On the other hand, in the second speed position the spindle shuts off the throttle valve pressure line and receives the holding pressure on the pressure absorption surface. In the changed-down position, the control pressure, which corresponds to the vehicle speed, and the throttle valve pressure, which corresponds to a spring force and a throttle valve aperture, are fed to the spindle in opposition to one another so that the spindle is moved according to a ratio between the control pressure, the spring force and the throttle valve pressure.