Micromachined structure usable in pressure regulating microvalve and proportional microvalve

Abstract

A microvalve device includes a first plate, a second plate and a third plate. The second plate is connected between the first plate and the third plate. The second plate contains a stationary element and a moveable plate valve slider element. The slider element variably restricts the flow of a fluid through the microvalve device. The second plate defines a first supply port, an output conduit, and a return port. In a pressure increase position, the slider element allows the fluid to flow from the first supply port to the output conduit. In a pressure hold position, the slider element isolates the output conduit from both the first supply port and the return port. The pressure decrease position allows fluid to flow from the output conduit to the return port. Pressure from the output conduit acts against a first axial end face of the slider element. In a pressure regulating valve embodiment of the microvalve device, the second axial end face of the slider element (opposite the first axial end face) is acted upon by a spring, with the position of the slider element being determined by a balancing of the force exerted by the spring and the force exerted by the fluid acting against the first axial end face. In a proportional microvalve embodiment of the microvalve device, the second axial end face of the slider element (opposite the first axial end face) is acted upon by pressurized fluid in a control chamber, with the position of the slider element being determined by a balancing of the force exerted by the fluid acting against the first axial end face and the force exerted by the fluid acting against the second axial end face. Preferably, a buffer piston extends axially from the first axial end face.