The main function of the hub bearing is to bear the load and provide precise guidance for the rotation of the hub. It bears both axial load and radial load, and is a very important component. Traditional automobile wheel bearings are composed of two sets of tapered roller bearings or ball bearings. The installation, oiling, sealing and clearance adjustment of the bearings are all carried out on the automobile production line. This structure makes it difficult to assemble in automobile production plants, high cost, and poor reliability, and the bearings need to be cleaned, oiled and adjusted when the automobile is maintained at the repair point. The hub bearing unit is developed on the basis of standard angular contact ball bearings and tapered roller bearings. It integrates two sets of bearings into one body. It has good assembly performance, can omit clearance adjustment, light weight, compact structure, and load capacity. Large, sealed bearings can be pre-loaded with grease, omit the external hub seal and avoid maintenance, etc., have been widely used in cars, and there is a tendency to gradually expand their applications in trucks.

Installation and use
In the past, single-row tapered roller or ball bearings were used in pairs for the most common wheel hub bearings for cars. With the development of technology, car hub units have been widely used in cars. The use range and usage of wheel hub bearing units are increasing day by day, and now it has developed to the third generation: the first generation is composed of double row angular contact bearings. The second generation has a flange for fixing the bearing on the outer raceway, and the bearing can be simply sleeved on the axle and fixed with a nut. Makes the maintenance of the car easier. The third-generation wheel hub bearing unit uses the bearing unit to cooperate with the anti-lock brake system ABS. The hub unit is designed with an inner flange and an outer flange. The inner flange is bolted to the drive shaft, and the outer flange installs the entire bearing together. Worn or damaged hub bearings or hub units will cause unsuitable and costly failures of your vehicle on the road, and even cause damage to your safety.

Please pay attention to the following matters in the use and installation of wheel bearings:
1. In order to ensure maximum safety and reliability, it is recommended that you always check the wheel hub bearings regardless of the age of the vehicle-pay attention to whether the bearings have early warning signs of wear: including any frictional noise during rotation or the suspension combination wheel is turning Decelerate abnormally from time to time. For rear-wheel drive vehicles, it is recommended that the front wheel hub bearings should be lubricated when the vehicle has traveled to 38,000 kilometers. When replacing the brake system, check the bearing and replace the oil seal.
2. If you hear the noise from the hub bearing part, first of all, it is important to find the location of the noise. There are many moving parts that may produce noise, and it may also be that some rotating parts are in contact with non-rotating parts. If it is confirmed that the noise is in the bearing, the bearing may be damaged and needs to be replaced.
3. Because the working conditions of the front wheel hub causing the bearing failure on both sides are similar, even if only one bearing is broken, it is recommended to replace it in pairs.
4. Hub bearings are more sensitive. In any case, you need to use the right method and the right tools. In the process of storage, transportation and installation, the components of the bearing cannot be damaged. Some bearings require greater pressure to press in, so special tools are required. Be sure to refer to the automobile manufacturing manual.