Commercial vehicle wheel hub bearing lubrication characteristics

The car wheel hub has gone through the first generation of ordinary double-row bearings, the second generation of single-flange double-row bearings, and the third generation of double-flange double-row bearings. At present, the double-flange double-row bearings are integrated with the universal joint, which are characterized by high temperature, high speed and micro-wear; the commercial vehicle drum wheel has gone from two independent tapered roller bearings to two integrated tapered roller bearing sets, which are characterized by extreme pressure and long life.

As one of the most important components of automobiles, the lubrication technology of wheel hub bearings is closely related to the continuous improvement of the bearings themselves. The wheel hub bearing grease itself should be able to form a firm oil film to provide wear-resistant and reliable lubrication for the friction parts. The grease used is required to have five main properties: high temperature resistance, structural stability, wear resistance, water resistance, and long life:

First, excellent high temperature resistance, ensuring that the vehicle meets the requirements of 130~150℃ under harsh conditions such as heavy load and continuous braking in mountainous downhill, and the grease dropping point is mostly around 290°C.

Second, good mechanical stability and adhesion. Ensure that the grease is not easily softened and lost under the long-term mechanical shearing effect generated by the operation of the bearing, which is conducive to preserving the lubricating oil film on the bearing surface, avoiding early failure of bearing lubrication or causing safety problems; the change in the cone penetration of the grease after 100,000 working times should not be greater than 15%.

Third, sufficient wear resistance and load-bearing capacity. Ensure that the wheel hub bearing will not cause abnormal wear even under the condition of impact load; such as PB above 980N.

Fourth, good water resistance and rust prevention. It can be used in harsh driving environments, and even in conditions of water pollution, it can prevent corrosion of chassis components and protect metal parts.

Fifth, a long service life and excellent lubrication performance. Avoid the wheel hub bearing from bearing axial and radial loads at the same time, which is easy to cause metal fatigue and peeling, extend the maintenance cycle, and require a maintenance mileage of 50,000 to 100,000 kilometers.

In addition, good low-temperature starting performance, antioxidant stability and rubber compatibility are also required. In general, extending the service life of commercial vehicle wheel hub bearing grease depends on the joint improvement of bearing and grease quality.

Selection and application of commercial vehicle wheel hub bearing grease

According to the specific working conditions of commercial vehicle wheel hub bearings, affected by vehicle type, vehicle speed, road conditions and climate environment, the lubrication conditions of automobile wheel hub bearings are relatively harsh, requiring wheel hub bearing grease to have excellent mechanical stability, water resistance and rust prevention, oxidation stability, adhesion and extreme pressure wear resistance. The wheel hub grease base oil is mainly mineral oil, supplemented by semi-synthetic, and EP and solid anti-wear agents are added.

Ordinary commercial vehicles generally use general automotive lithium-based grease, MP multi-effect lithium-based grease and other general automotive lithium-based grease series products. With the improvement of overall automotive technology and road conditions, modern automobiles are developing towards high efficiency, heavy load, energy saving and environmental protection, and more stringent requirements are put forward for the long life and temperature resistance of automotive grease, especially for wheel bearing grease under high speed and heavy load conditions. Ordinary lithium-based grease is increasingly exposing its defects. Poor temperature resistance, poor impact load resistance, high temperature loss and poor adhesion have become its fatal weaknesses.