The positioning sleeve plays a positioning role. Positioning means that the workpiece has an accurate position in the fixture. There is a gap between the short sleeve and the shaft. The shaft is a long shaft. After positioning, the far end swing of the long shaft is far greater than the gap, so it cannot be accurately positioned. Positioning is not a limit. In life, short sleeve positioning, the long axis cannot rotate around the xy axis, but it is a limit. During long sleeve positioning, only the amount of clearance affects the positioning accuracy, so it can limit the rotation of xy axis.

Scope of application

The structure is simple and the manufacture is simple, but the ease accuracy is not high, so it is only suitable for precise positioning of the base plane. The inner hole axis is the limit datum, and the inner hole surface is the limit datum. In order to limit the axial degree of freedom of the workpiece, it is often combined with the end face for positioning.