短语词组短语rotary elbow joint 活动肘关节rotary y joint 旋转连接rotary steam joint 旋转式汽管接头annular rotary joint 环状旋转接头rotary joint trouble 旋转接头故障air rotary joint 旋转接头optical rotary joint 光旋转连接器Waveguide rotary joint 波导旋转关节 返回 rotary joint