Fluid controller

A controller for controlling fluid flow from a source to a motor, said controller having an inlet port for connection to the source, a return port for connection to a reservoir, and a pair of working ports for connection to opposite sides of the motor, said controller further including a metering section and a control valve comprising a pair of relatively rotatable plate valve members having facing end surfaces in sliding abutting relation with each other, said plate valve members having a neutral condition blocking flow from the inlet port to the metering section and being rotatable away from said neutral condition to an operating condition to form flow passages directing metered flow to the motor through one working port and return flow from the motor to the reservoir through the other working port, a pressure dam groove disposed in the facing end surface of one of said relatively rotatable plate valve members, said pressure dam groove communicating with said return port when said plate valve members are in said neutral condition and disposed so as to be positioned between flow passages at metered fluid pressure and flow passages at return pressure when the plate valve members are rotated to an operating condition, the abutting facing end surfaces of said relatively rotatable plate valve members cooperating to block flow from the inlet port through the pressure dam groove to the return port when the plate valve members are in the neutral condition and to form a static body of fluid in said pressure dam groove in response to movement of said plate valve members to an operating condition, and fluid passage means in the facing end surface of the other plate valve member defining part of a fluid passage communicating said static body of fluid in said pressure dam groove with said inlet port in response to movement of said plate valve members to said operating condition to bring the pressure in said pressure dam groove to inlet pressure in order to minimize leakage of metered fluid to the return port.

A controller for controlling fluid flow from a source to a primary motor and to an auxiliary motor, said controller comprising a metering section for metering fluid flow in response to an input signal and a control valve section for directing fluid flow to the auxiliary motor and to the primary motor in response to said input signal, said control valve section comprising a series of adjacent plate valve members, said series of plate valve members being biased to a neutral condition and being relatively movable away from said neutral condition to place said controller in an operating condition, means for effecting relative movement of said plate valve members in response to said input signal to position said plate valve members in said operating condition, said plate valve members defining fluid passages for directing all flow from the source to the auxiliary motor when said plate valve members are in said neutral condition, said plate valve members defining other fluid passages for directing a flow of fluid from the source to said metering section and from said metering section to the primary motor when said plate valve members are in an operating condition, and said plate valve members having relatively movable surfaces which cooperate to restrict flow to the auxiliary motor as a function of the extent of the relative movement of the plate valve members away from said neutral condition.