Hydraulic servo control for automotive automatic gear box

摘要

The hydraulic servo for an automatic gear has a cylinder, a piston and a rod. The piston subdivides the cylinder into a closed hydraulic chamber and a back-chamber which has an opening to the inner chamber within an automatic gear box. The rod slides back and forth within the piston over a predetermined distance. A friction grip element is held by the rod which extends from one end of the cylinder following hydraulic pressure on the hydraulic chamber. A passage runs between the rod and piston which is opened or closed by relative rotation between the two, either making or interrupting the link between the hydraulic chamber and the back chamber. At the end of the piston return stroke, the passage to the hydraulic chamber is closed by a blower unit.