Direct-acting water pressure overflow valve with damping piston

The invention relates to a direct-acting water pressure overflow valve with a damping piston. The overflow valve comprises an end cover, as well as a valve seat, a valve core, a left spring seat, a guide sleeve, a spring, a right spring seat and a pressure regulating screw which are arranged in a valve body sequentially; an annular groove and a cross through hole are arranged in the valve seat, the valve core is arranged in an axial through hole of the valve seat, the end part of the valve core is provided with a countersunk groove, a cylindrical surface at the tail part of the valve core and the axial through hole of the valve seat form a guide surface, and cylindrical surface at the tail part of the valve core and a valve port formed by the valve seat form a cone valve structure; the valve core is in contact fit with the left spring seat; the left spring seat is guided by the inner bore of the guide sleeve, the guide sleeve is provided with a small through-flow hole, and the right side of the guide sleeve is provided with the annular groove; the spring is positioned between the left spring seat and the right spring seat; and the pressure regulating screw is connected with the valve body by screw threads. The overflow valve is suitable for a pressure control element in a medium and high-pressure water hydraulic system using seawater, fresh water, a high water base or the like as a working medium. Compared with similar valves, the overflow valve has the advantages of simple structure, convenience for processing, low leakage, small vibration, low noise, good cavitation corrosion resistance and high working stability.