关键词: 有限转角力矩电机, 伺服阀, 输出力矩不对称

Abstract: The output torque of finite angle torque motor for a certain type of rotary servo valve was analyzed under different rotation directions, and a solution was proposed. The original prototype adopted a 6 poles, six-slot electromagnetic structure, which had cogging torque. In order to maintain the zero position of the rotor, the coil spring needed to overcome the cogging torque and generate a reverse torque. The orientation torque was opposite to the steering direction, while the torque of the coiling spring was not affected by the steering. The torque of the coiling spring led to the failure of asymmetric output torque of the motor under different rotaion directions. After fault location and simulation analysis, an improved scheme with 6 poles and 9 slots was proposed. The new electromagnetic scheme had negligible cogging torque, so the coil spring only needed to overcome the effect of slot torque to maintain the rotor zero position, and the torque generated by the coiling spring was negligible compared with the electromagnetic torque. Through the test of the new prototype, the output torque of the two rotating directions was basically the same ,which effectively solved the output torque asymmetry fault of the finite torque motor.

Key words: finite angle torque motor, servo valve, output torque asymmetry