The ring is driven by a motor, revolving at motor speed.
该（旋转）环由电动机带动，其转速等于电动机的转速。
2
A friction-reducing bearing consisting essentially of a ring-shaped track containing freely revolving hard metal balls against which a rotating shaft or other part turns.
The two unified switches are formed by the inlet door page revolving connecting rod, the sliding chute and the telescopic connecting rod through a ring movement.