Frequently Asked Questions about FAG Bearings

1. Peel off

Damaged state: When the FAG bearing rotates under load again, the raceway surface or rolling element surface of the inner ring and outer ring presents a fish-scale peeling phenomenon due to rolling fatigue.

Reason: The load is too high. Improper installation (non-linear) moment load foreign matter intrusion, water ingress. Poor lubrication, inappropriate lubricant FAG bearing clearance is not appropriate. The accuracy of the FAG bearing box is not good, and the rigidity of the bearing box of the bearing box is not uniform, the deflection of the shaft is large, and the development caused by rust, erosion points, scratches and indentations (surface deformation phenomenon).

Measures: Check the size of the load and re-research the FAG bearing used to improve the installation method, improve the sealing device, and prevent rust during shutdown. Use lubricants of appropriate viscosity and improve lubrication methods. Check the accuracy of the shaft and FAG bearing housing. Check clearance.

2. Peel

Damaged state: showing a dark side with slight wear, there are many tiny cracks as deep as 5-10m from the surface on the dark side, and tiny peeling (micro peeling) occurs in a large area

Reason: Inappropriate lubricant. Foreign matter has entered the lubricant. Poor lubricant causes rough surface. The surface finish of the paired rolling parts is not good.

Measures: Select lubricants to improve the sealing device to improve the surface finish of the paired rolling parts.

3. Card injury

Damage state: The so-called sticking damage is the surface damage caused by the aggregation of micro burns in the part of the sliding surface damage. Linear flaws in the circumferential direction of the sliding surface and the rolling surface. The trochoidal flaw on the roller end face is close to the jamming on the collar face of the roller end face.

Reason: Excessive load, excessive preload. Poor lubrication. Foreign body bites. The inclination of the inner ring and the outer ring, and the deflection of the shaft. The accuracy of the shaft and FAG bearing housing is poor.

Action: Check the size of the load. Preload should be appropriate. Improve lubricants and lubrication methods. Check the accuracy of the shaft, FAG bearing housing.

4. Fracture

Damage state: The so-called fracture refers to a small part of the fracture due to the impact or excessive load applied to the local part of the rib or roller corner of the raceway wheel.

Cause: It was hit during installation. The load is too high. Poor use such as falling.

Action: Improve the installation method (use shrink-fit, use appropriate tool clips). Correct load conditions. The FAG bearing is installed in place so that the rib is supported.

5. Cracks, cracks

Damage state: The so-called crack refers to the crack damage of the raceway wheel or rolling element. If continued use will also include crack growth cracks.

Reason: Excessive interference. Excessive load, shock load. Stripping has developed. Heat generation and fretting wear due to the contact of the raceway wheel with the mounting member. Heating caused by creep. The taper angle of the taper shaft is poor. The cylindricity of the shaft is poor. The fillet radius of the shaft step is larger than that of the FAG bearing chamfer, causing interference with the FAG bearing chamfer.

Measures: The amount of interference is appropriate. Check load conditions. Improve installation method. The shape of the shaft should be appropriate.

6. Indentation

Damaged state: When small metal powder, foreign matter, etc. are bitten, dents are formed on the raceway surface or the rotating surface. Concave surfaces (Brinell hardness indentations) are formed in the pitch intervals of the rolling elements due to shocks received during installation or the like.

Cause: Foreign matter such as metal powder bites. Excessive shock loads during assembly or transportation.

Measures: Impact the bushing. Improve sealing device. Filter oil. Improve assembly and usage.

7. Pear skin pitting

Damage state: Weak glossy dark pear-like pitting on the raceway surface.

Cause: Foreign objects bite during lubrication. Condensation due to moisture in the air. Poor lubrication.

Action: Improve the sealing device. Fully filter the lubricating oil. Use a suitable lubricant.

8. Wear

Damaged state: The so-called wear is the wear of the raceway surface or rolling surface, the roller end surface, the collar surface and the concave surface of the cage due to friction.

Reason: foreign body intrusion, development caused by rust and electric corrosion. Poor lubrication. Slip due to irregular motion of rolling elements.

Action: Improve the sealing device. Clean the FAG bearing housing. Fully filter the lubricating oil. Check lubricant and lubrication method. Prevent non-linearity.

9. Fretting wear

Damaged state: The wear caused by the relative repeated micro-slip between the two contact surfaces occurs on the contact portion of the raceway surface and the rolling elements. Due to the occurrence of reddish-brown and black wear powder, it is also called fretting corrosion.

Cause: Poor lubrication. Small amplitude rocking motion. Insufficient interference.

Action: Use an appropriate lubricant. Add preload. Check the interference. Apply lubricant to mating surfaces