Seven Measures To Improve Engine Mainshaft Bearing Reliability

Seven major measures can improve the reliability of engine main shaft bearings:

1. Improve processing accuracy. Improve the machining accuracy of each bearing component, which should not be lower than level 4 accuracy, and correctly select reasonable clearances and matching values during assembly. During assembly, the bearings must be inspected according to the contents specified by the special technical conditions, such as visual inspection, checking whether there are surface defects and rust exceeding the regulations, and rechecking the dimensions and original clearance of the mating joints, etc.
2. The deflection between the bearing ring and the axis cannot be large. For long-life bearings that require high reliability, the deflection of the bearing ring and axis must not exceed the allowable standard under working conditions (for bearings with a life span greater than 1000h, the deflection must not exceed 0.5′).
3. Use three-point contact ball bearings. Replacing 4-point contact ball bearings with 3-point contact radial thrust ball bearings can improve bearing reliability.
4. Steel cage. Replace the bronze cage with a steel cage (mostly used in Russian-made engines), and the surface of the cage is preferably silver-plated.
5. The temperature difference between the inner and outer rings is less than 5℃. If the heat of the bearing can be effectively taken away and kept within the width of the bearing and there is a relatively uniform temperature field between the outer rings, and the temperature difference between the inner and outer rings is not greater than 5°C, the reliability of the bearing can be improved.
6. Reasonably select the gap between the end face of the roller rod and the rib. In roller rod bearings, the axial clearance between the end face of the roller rod and the rib should be between 0.04~0.06mm. If the gap is larger or smaller than this value, the reliability of the roller rod bearing will be reduced.
7. Use fine oil filter. Use a lubricating oil filter with a higher filtration degree (the best filtration degree is 5~15μm) to filter the lubricating oil.

Warm reminder: Among engine main shaft bearings, roller rod bearings only bear the radial load of the rotor, while ball bearings bear not only radial loads but also axial loads. The working conditions are much worse than roller rod bearings. In order to reduce the load on the ball bearing and improve the reliability of the engine, a roller bearing can be placed side by side on the ball bearing. The roller bearing is used to bear the radial load, and the ball bearing only bears the axial load. This greatly reduces the load on the ball bearing and improves its working conditions.