在LEGO Mindstorms 系列與BioTrans RoSys系列機器人組件中軸套特指銀灰色的樂高標準軸固定器，分全軸套和1/2軸套兩種。
A bushing is a sleeve on a propeller shaft or a yoke shaft. The bearing is a component that fixes and reduces the friction coefficient of the load during the mechanical transmission process.
The same thing about bushings and bearings is that both bear the load on the shaft.
The difference between the two is that the sleeve is of integral structure, and the relative movement between the shaft and the sleeve is when rotating; and the bearing is split, and the inner and outer rings of the bearing are relatively moved when rotating. But in essence, the bushing is actually a kind of sliding bearing.
The bearing pad is equivalent to the outer ring of the sliding bearing, the bushing is integral and the opposite axis is moving, while the bearing bush is segmented and the opposite axis is rotating.
In the LEGO Mindstorms series and BioTrans RoSys series of robot components, the sleeves are specifically referred to as the silver-gray LEGO standard shaft holders, which are divided into full sleeves and 1/2 sleeves.