Electrical linear force motor for servo controls, fluid valves, and the like

摘要

The invention relates to an electro-mechanical force motor device for converting a controlled electrical input signal into a mechanical movement, particularly for actuation of a hydraulic pilot or servo device. The basic component of the invention is a linear electric force motor with its principal components coaxially disposed and arranged to achieve linear mechanical displacement in accordance with an applied signal of voltage. The armature or coil element of the linear force motor is coupled to a double-acting bellows, which not only serves as a double- acting return spring, but also totally isolates the magnetic and electro magnetic elements of the force motor from the controlled system. This is of particular significance in connection with the electro-hydraulic pilot and servo devices, for example, in which the circulating hydraulic fluid inevitably contains suspended magnetic particles which otherwise can eventually accumulate on the magnetic components of the force motor and impede its normal functioning.