What is the reason for aircraft engine bearing slippage?

1. Insufficient axial load: When the axial load is insufficient, the radial force acts on the bearing and is transmitted to the steel ball so that it cannot form an effective contact angle. The steel ball contacts the two half inner rings at the same time, forming multiple point contact, resulting in slipping failure.

2. Insufficient radial clearance: The inner ring of the bearing has a peach-shaped groove structure. When the radial clearance is insufficient, slipping and scratching will occur on the surface of the steel ball and the surface of the groove.

3. Steel ball spin: In a ball bearing that rotates at high speed and bears a certain axial load, a centrifugal force will be generated that deviates from the center of the ring and is distributed in the radial direction, causing the stress of the bearing to change. Under the action of centrifugal force, the force of the steel ball acting on the outer ring channel is greatly increased, while the force between the steel ball and the inner ring channel is reduced. The change of the force on the inner and outer ring channels will affect the change of the contact angle between the steel ball and the inner and outer rings, causing the outer ring contact angle to become smaller and the inner ring contact angle to become larger. If the contact angle of the inner and outer rings is very different, it will affect the friction state in the bearing, causing the steel ball to spin on the inner ring channel. The direction of rotation is around the connection point between the steel ball and the inner ring contact point and the center point of the steel ball. The spool rotates. The direction of self-rotation causes sliding friction in the contact pair, which will cause sliding wear on the surface of the steel ball in contact with the inner ring channel.

4. Excessive axial load: When the three-point contact ball bearing is working, the steel ball is in contact with the load-bearing inner ring, and there is a residual gap with the non-load-bearing inner ring. When the residual gap is zero or negative, multi-point contact will occur, causing slipping failure.

5. High speed and small load: The rotors of aeroengines are made lighter, so that the radial load on the acting bearings is small. In addition, when the aircraft is maneuvering, the load acting on the bearings will be smaller under certain circumstances, and even zero load will occur. The unbalanced force of the rotor will also offset some of the radial loads acting on the bearings under certain circumstances, resulting in light or zero load on the bearings. Under high speed, the rollers tend to break away from the inner ring raceway under the action of large centrifugal force, thus causing slipping failure.

The above are possible reasons for aircraft engine bearing slippage. In order to ensure the normal operation of aeroengines, bearings need to be inspected and maintained regularly to detect and solve problems in a timely manner.