是在伺服系统中控制机械元件运转的发动机，是一种补助马达间接变速装置。伺服电机是可以连续旋转的电－机械转换器。作为液压阀控制器的伺服电机，属于功率很小的微特电机，以永磁式直流伺服电机和并激式直流伺服电机最为常用-Servo control system in the operation of the engine mechanical components, is a servomotors device. Continuous rotation servo motors can be electric- mechanical converter. As a hydraulic valve controller of the servo motor, is a small power micro motor, permanent magnet DC servo motor and DC servo motor and excited the most commonly used