Principles of Preloading Ball Bearings
Preloading Angular Contact Bearings Reason and Method
- Preloading an angular contact ball bearing (ACBB) is performed to lock in a precision axial displacement of the bearing outer ring relative to the inner ring.
- This is achieved by stick out grinding the bearing components at a fixed axial applied load, such that the inner and outer ring faces are flush with each other within a set axial force tolerance.
- Angular contact ball bearing (ACBB) deflection is not linear and has a steep knee, i.e. very light loads can deflect an angular contact ball bearing (ACBB) to a greater extent than changes in load can at higher loads.
- Locking in this precision axial displacement (or force depending on how you look at it) takes this steep knee out of the preloaded bearing deflection curve.
- Preloading of angular contact ball bearings (ACBB) is typically performed at three different preload levels.
- Light Preload (125,000 PSI Max Hertzian Contact Stress)
- Normal Preload (175,000 PSI Max Hertzian Contact Stress)
- Heavy Preload (225,000 PSI Max Hertzian Contact Stress)
Learn how preloading impacts bearing stiffness.
Graphs of Axial Preload Force and Max Hertzian Contact Stress (PSI) vs. Preload Gap
