Positioning preloading and constant pressure preloading of bearings are two different preloading methods, each with different characteristics and applicable scenarios.
Positioning preloading is a preloading method that ensures that opposed bearings do not change their axial relative position during use. It mainly includes the following methods:
1. Adjust the width difference or axial clearance: Before implementing preloading, adjust the width difference or axial clearance of the combined bearing first, and then tighten it. This ensures that the bearing maintains a stable axial position during use.
2. Use an adjusted spacer ring or caulking piece: Preload the bearing by adjusting the size of the spacer ring or caulking piece. This method can accurately control the preload force of the bearing and ensure its stability during operation.
3. Tighten the screws or nuts with adjustable axial clearance: During the preloading process, by adjusting the tightening degree of the screws or nuts, the axial clearance of the bearing can be adjusted, thereby achieving preloading of the bearing. This method requires adjustment while measuring the starting friction torque to obtain the appropriate preload force.
Constant pressure preloading is a method of applying appropriate preloading to bearings through cylindrical springs, butterfly springs or other coil springs and disc springs. Even if the relative position of the bearing changes during use, the preload amount can remain basically constant. Constant pressure preload is usually used in high-speed rotating angular contact bearing pairs to ensure that the bearings can maintain a stable preload state during operation.