Car wheels have experienced the first generation of ordinary double-row bearings, the second generation of single-flanged double-row bearings, the third generation of double-flanged double-row bearings, to the present double-flanged double-row bearings and universal joint integration, characterized by high temperature, high speed and fretted wear; Commercial vehicle drums range from two independent tapered roller bearings to integrated sets of two tapered roller bearings, characterized by extreme pressure and long life.
Hub bearing is one of the most important components of automobile, and its lubrication technology is closely related to the continuous improvement of bearing itself. Hub bearing grease itself should be able to form a firm oil film to provide wear-resistant and reliable lubrication for the friction parts, requiring the use of grease with high temperature resistance, structural stability, anti-wear load, water resistance, long life and other five main properties:
First, excellent high temperature resistance, to ensure that the vehicle in heavy loads, downhill continuous braking conditions such as mountain braking, the maximum use temperature to meet the requirements of 130~150 °C, grease drop point more than 290°C above and below.
The second is good mechanical stability and adhesion. Ensure that the grease is not prone to excessive softening and loss under the long-term mechanical shear caused by the bearing operation, which is conducive to preserving the lubricating oil film on the bearing surface and avoiding early bearing lubrication failure or causing safety problems; The change of 100000 working cone penetration of grease should not be greater than 15%.
Third, sufficient wear resistance and bearing capacity. Ensure that the hub bearing will not cause abnormal bearing wear even under the condition of impact load; For example, PB is above 980N.
Fourth, it has good water and rust resistance. Can be applied to harsh driving environment, even in the condition of water pollution can prevent chassis components such as corrosion, protect metal parts.
Five is a long service life, excellent lubrication performance. Avoid hub bearings bearing axial and radial load at the same time, which is easy to cause metal fatigue caused by spalling, extend the maintenance cycle, and require maintenance mileage of five to one hundred thousand kilometers.
In addition, it also requires good low-temperature starting performance, anti-oxidation stability and rubber compatibility. In general, extending the service life of commercial vehicle hub bearing grease depends on the joint improvement of bearing and grease quality.
Selection and application of commercial vehicle hub bearing grease
According to the specific working conditions of commercial vehicle hub bearings, affected by the model, speed, driving road conditions and climate environment, the lubrication conditions of automotive hub bearings are more demanding, requiring hub bearing grease to have excellent mechanical stability, water and rust resistance, oxidation stability, adhesion and extreme pressure wear resistance, hub grease base oil mineral oil mainly, semi-synthetic as a auxiliary. Add EP and solid anti-wear agent.
General commercial vehicles generally use general automotive lithium grease, MP multi-effect lithium grease and other general automotive lithium grease series products. With the improvement of the overall technology of automobiles and the improvement of road conditions, modern automobiles are developing towards high efficiency, heavy duty, energy saving and environmental protection, and more stringent requirements are put forward for the long life and temperature resistance of automobile grease, especially in the case of high-speed and heavy duty wheel bearing grease, ordinary lithium based grease is more and more exposed to its defects. Problems such as poor temperature resistance, poor impact load resistance, high temperature loss and poor adhesion have become its fatal weaknesses.
The load capacity of more than 5 tons and large buses should use extreme pressure compound lithium based products such as Kunlun HP-R high temperature grease and Kunlun heavy duty vehicle wheel grease, which can meet the performance requirements of high-speed heavy duty vehicles for grease. For example, 35 tons of commercial vehicle hub bearings, after applying Kunlun HP-R high temperature grease driving 68635km, the hub bearing hub still has grease attached to maintain the lubrication effect.