Performance Requirements For Bearing Lubrication
Bearing lubricating oil is crucial to the performance of wheel hub bearings. It directly affects the wear resistance and service life of the bearings as well as the safety and reliability of the entire vehicle.
Regarding the requirements of wheel hub bearing lubricant, the following is a detailed performance analysis:
Excellent high temperature resistance:
When a car is driving under conditions such as heavy loads and downhill slopes in mountainous areas, the braking system will generate a lot of heat, and the wheel hub bearings will also be affected by high temperatures.
The grease needs to have a high dropping point (generally above 290°C) to ensure that it will not evaporate or be lost quickly under extreme high temperatures and to ensure that the bearings are continuously lubricated and protected.
Good mechanical stability and adhesion properties:
When the bearing operates at high speed, the grease will be subjected to strong shear force. If the mechanical stability is poor, the grease will soften and lose, and the stability of the oil film cannot be maintained.
Good adhesion properties can ensure that the grease adheres tightly to the bearing surface, preventing oil film rupture and dry friction of the bearing.
The change in cone penetration for 100,000 operations should not be greater than 15%, which is one of the important indicators for evaluating the mechanical stability performance of grease.
Adequate wear resistance and load-bearing capacity:
Bearings will be subject to various impact loads during operation, and the grease needs to have sufficient wear resistance and load-bearing capacity to protect the bearings from damage.
The PB value (maximum non-seizure load measyred by the four-ball method) is above 980N, which ensures the performance of the grease under heavy load conditions.
Good water and rust resistance:
Cars may encounter humid or water-polluted environments while driving. Grease needs to have good water resistance to prevent moisture from invading the interior of the bearings and causing corrosion.
At the same time, the grease also needs to have anti-rust properties to protect the bearing surface from corrosion.
Long service life and excellent lubrication properties:
The long life of the grease means less frequent replacement and lower maintenance costs.
Excellent lubrication performance can ensure that the bearings are fully lubricated during operation, reduce wear and friction, and extend the service life of the bearings.
The required maintenance mileage reaches 50,000 to 100,000 kilometers, which reflects the expectation of long life performance of the grease.
In addition to the above five main properties, the grease is also required to have good low-temperature starting performance, antioxidant stability and compatibility with rubber. These properties are to ensure that the grease can provide reliable lubrication protection for the wheel hub bearings under various working conditions, extend the service life of the bearings, and improve the safety and reliability of the entire vehicle.