Valve device for use in construction machinery with hydraulic control of working cylinder and drive motors, has valve housing with power connector for connection to hydraulic consumer, return port, pump channel, and back pressure channel

摘要

The valve device (10) has a valve housing (16) with a power connector (A,B) for the connection to a hydraulic consumer (18), a return port (T), a pump channel (P) guiding a pump pressure, and a back pressure channel guiding a back pressure. The pending part of the back pressure is controllable at a control side (28) of a control piston (26) of a pressure balance (24) over a pressure control groove (32) formed on the control piston. The part of the back pressure is present additionally at the control side of a changeover valve (36).