Linear actuator with feedback position sensor device

Abstract

The present invention provides an electrically powered linear actuator. An elongated cylinder formed of a magnetic material and having an internally threaded bore is rotatably supported relative to the housing assembly. Magnets are mounted about an outer circumference of the cylinder to form an armature within the motor assembly. The thread engaging portion of the actuator assembly is moved along the threaded extent of the cylinder on rotation of the cylinder. Thus, the cylinder functions as an armature drive cylinder. The actuator assembly further includes a feedback position sensor. This sensor provides output shaft position location information to a controller which, in combination with a servo-amplifier, operates the linear actuator in a closed-loop feedback control environment. Further, such an actuator can be utilized in precision volumetric pump applications. In a volumetric pump application, the output shaft of the actuator includes a cylinder head which travels within a cylinder. Two pump strokes may be defined as a first intake stroke (e.g., when the output shaft is retracted) and a second exhaust stroke (e.g., when the output shaft is extended). Valves are utilized to control the entry and exit of fluid and other materials to and from the pump.