Design of A Limited-Angle Torque Motor with Magnetic Zero-Returner for Aviation Fuel Valve

This paper presents the design procedure of a 4-pole-4-slot inner rotor limited-angle torque motor (LATM) with magnetic zero-returner (ZR) equipped in fuel valves especially for aviation application. Firstly, the LATM topology is selected based on the electromagnetic performance comparison among three topology candidates. By optimizing the shape of tooth-tips and PM array, the proposed LATM is able to produce constant output torque and almost eliminate cogging torque within the whole working range up to 40°. Besides, the influence of tooth-tip and PM's shape on torque characteristics are investigated by finite element analysis (FEA). Moreover, to guarantee the operating reliability for aviation application, a magnetic ZR is designed for the proposed LATM, which breaks out the limited service life and mechanical fatigue of the traditional spring ZR. Finally the general assembly of the proposed LATM is designed and the prototype is manufactured. The testing results match well with the FEA data and confirm the feasibility and superiority of the proposed LATM for fuel valve applications.