Patent ID: 7351179
Filing Date: 2008-04-01
Classification: H02K,Y10T

Abstract:
1. A stepper motor driven actuator comprising: a stepper motor; a cam operatively connected to the stepper motor, the cam rotating position in response to stepping of the stepper motor, the cam positioned within a valve body having an inlet port, a rod port, a head port and at least one drain port; a control piston positioned within the valve body and having a plurality of nozzles positioned on opposite sides of the cam in close proximity to a surface of the cam and movable between a null position and flow positions, each of the plurality of nozzles having a flow path, the control piston moving as a result of a pressure imbalance at the ends of the control piston occurring in response to a change in position of the cam such that a difference between a first gap between the surface of the cam and one of the plurality of nozzles and a second gap between the surface of the cam and an other of the plurality of nozzles is minimized; and an actuator having a piston integral to a rack that is operably coupled to the cam, the piston having a first side and a second side, the first side being in fluid communication with the head port and the second side being in fluid communication with the rod port, the cam moving in response to the rack moving.