A keyway is machined on the outer race for the connection to the drive or drive member centered on its outside. 外环有键槽用来与驱动件或被驱动件结合，并以外环为固定中心线。
You can control the motor moving left and right on the curtain staff to drive the window curtain close or open eadily by pressing the button of the controller only. 使用时，只需轻轻一按遥控器或线控器按钮，控制器即指挥电机在滑杆上左右运动，电机通过窗帘环驱动窗帘开闭。
