Magnetorheological fluid pumping system

Abstract

An improved magnetorheological fluid pumping system and method are provided which effectively dispense a predetermined amount of magnetorheological fluid for delivery to a MR device such as a damper assembly, for example, during manufacture. The fluid pumping system includes a pump having inlet and outlet valves, a reciprocally mounted piston, a stroke operator device for controlling the movement of the piston and an electronic controller for operating the stroke operator device and the inlet and outlet valves. Importantly, the inlet and outlet valves include an annular flow gap and a magnetic field generating assembly operable in an energized state to generate a magnetic field across the flow gap to cause magnetorheological fluid flowing through the gap to experience a magnetorheological effect sufficient to prevent flow through the gap and in a de-energized state to permit flow through the gap. In one embodiment, the system includes inlet and outlet valves mounted at one end of a pump housing on opposite sides of a common feed chamber to control fluid flow into and out of a pump chamber. In a second embodiment, the system includes an inlet valve integrated into the piston for controlling flow between a receiving chamber on one side of the piston and the pump chamber on the opposite side of the piston. The valves are alternately energized and de-energized before retraction and dispensing strokes of the piston resulting in simple effective control of fluid dispensing.