Pressure-limiting hydraulic valve

摘要

A pressure-limiting valve for hydraulic fluids comprises a stepped switching piston which is loaded by a closing spring to oppose high fluid pressure obtaining in an inflow duct of the valve. Radial transverse bores branch from an axially-extending bore in the switching piston. When the setting pressure established by the closing spring is exceeded, the transverse bores in the piston move past an O-ring seal as the piston compresses the spring, and pressure fluid thus flows from the axially-extending bore into a discharge duct of the valve. The stepped switching piston is guided in a pressure chamber by a portion of its cross-section which is greater than that in the zone of the O-ring seal. Adjacent the inflow duct, the axially-extending bore in the piston has a reduced flow cross-section. Further radial bores lead from the axially-extending bore in the piston in the region of the stepped portion of the latter.