High-Thrust Linear Actuator Based on Double Corner-Pole Airgaps for Proportional Relief Valve

This letter presents a high-thrust linear actuator for use in a proportional relief valve, based on double corner-pole airgaps formed by the structure of welding sleeve and step armature. The magnetic flux through the double corner-pole airgaps are divided into three parts of two radial fluxes (Φ1, Φ3) and one axial flux (Φ2), resulting in a linear characteristic with high-thrust force on the armature of the actuator. Parameter improvement in the limited space is analyzed based on modeling, and optimized results for a prototype actuator were obtained. The experimental and simulation results agree well. The prototype actuator can produce a thrust force of 110 N with a rated power of 12 W, and is linear within 4%, with 2% hysteresis over the displacement range of 0.8 to 2.3 mm. The force step response time of the actuator reaches 51 ms, and the force frequency response (−3 dB) reaches 36 Hz for a displacement of 1.5 mm.