Patent ID: 6263913
Filing Date: 2001-07-24
Classification: F15B,Y10T

Abstract:
A hydraulic multiway valve, comprising:a housing defining a consumer chamber, a return flow chamber, and a pressure chamber positioned between the consumer chamber and the return flow chamber, and the housing further defining a pump channel open to the pressure chamber, a consumer channel open to the consumer chamber, and a reservoir channel for being open to the return flow chamber;a main piston movably positioned in the housing, the main piston extending through the pressure chamber and having opposite ends respectively positioned in the consumer chamber and the return flow chamber, and the main piston defining a central channel that extends through the main piston and is open at the opposite ends of the main piston so that the consumer chamber and the return flow chamber are capable of being open to one another via the central channel while the central channel is open;a spring biasing the main piston toward a closed position in which the pressure chamber is closed to the consumer chamber due to seating between a flange of the main piston and a seat of the housing that separates the pressure chamber from the consumer chamber;a plunger piston positioned in the valve housing for coaxial movement relative to the main piston, the plunger piston comprises a seat end and is movable toward the main piston so that the seat end engages a predetermined one of the ends of the main piston to close the central channel, and the plunger piston is movable away from the main piston to an open position in which the central channel is open; anda magnet assembly for moving the plunger piston so that the seat end of the plunger piston moves into contact with the predetermined end of the main piston to close the central channel, and the magnet assembly is also for moving the plunger piston so that the force of the spring is overcome and the main piston is moved to an open position in which the pressure chamber is open to the consumer chamber due to unseating between the flange of the main piston and the seat of the housing;wherein the end of the main piston that extends into the return flow chamber slidingly engages an interior surface of the housing that defines the return flow chamber so that a seal is provided between the return flow chamber and the pressure chamber, and the cross section of the end of the main piston that extends into the return flow chamber corresponds substantially to the size of a seat surface of the flange of the main piston so that the main piston is substantially balanced, when the pressure chamber is closed.