HYDRAULIC VALVE

摘要

The invention relates to a hydraulic valve for exposing the supply pressure line of a hydraulic load supplied by a normal pressure source to a substitute pressure source. The invention should further develop the hydraulic valve so that the hydraulic valve automatically switches depending on whether the pressure is offered by the normal pressure source or by the substitute pressure source. In order to achieve said aim, the invention proposes a closing piece (2) arranged in a valve housing (1). The closing piece interacts with a closing seat (3) arranged in the housing (1) between the normal pressure connection (A) of the housing and the load connection (B) of the housing and can be acted on by a spring (4) and/or an opening piston (6) that can be pressurized with normal pressure through the normal pressure connection (A) in order to open the hydraulic valve and can be acted on by a closing piston (5) that can be pressurized with the substitute pressure through a substitute pressure connection (P) in order to close the hydraulic valve, wherein in the closing piston (5) a spring-loaded check valve (9) is arranged, which opens under the influence of the substitute pressure and releases a flow to the load connection (B) as soon as the substitute pressure has pushed the closing piston (5) and thus the closing piece (2) into the closed piston.