Installation and use of hub bearings

Hub bearings are the core components of the automotive hub system. Their main functions are to bear the load and provide precise guidance for the rotation of the hub. They need to bear both axial and radial loads. This component is widely used in passenger cars and trucks. Its structure has evolved from the traditional double-bearing combination to an integrated hub unit, which significantly improves assembly efficiency and reliability.

Traditional hub bearings use two sets of independent tapered roller or ball bearings, which have defects such as complex assembly and cumbersome maintenance. Modern hub bearings integrate double-row angular contact ball bearings or tapered roller bearings to form an integrated design, which has the advantages of free clearance adjustment, pre-grease and lightweight. It is divided into three generations according to technical iteration: the first generation is a double-row angular contact bearing, the second generation adds a fixed flange to simplify installation, and the third generation integrates an anti-lock braking system (ABS) to achieve mechatronics. Wear should be checked regularly during use, and replacement should be performed in pairs to maintain balance. The non-sealed type needs to control the grease filling amount to within 50% of the gap. ABS-related models need to pay attention to the installation direction of the magnetic thrust ring.

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 factories, high cost and poor reliability. In addition, the bearings need to be cleaned, oiled and adjusted when the car is maintained at the repair point. The wheel hub bearing unit is developed on the basis of standard angular contact ball bearings and tapered roller bearings. It integrates two sets of bearings and has the advantages of good assembly performance, no clearance adjustment, light weight, compact structure, large load capacity, grease can be pre-loaded for sealed bearings, no external hub seal and no maintenance. It has been widely used in cars and there is a trend of gradually expanding its application in trucks.

In the past, most of the wheel hub bearings for cars were used in pairs of single-row tapered roller or ball bearings. With the development of technology, car hub units have been widely used in cars. The scope and amount of use of wheel hub bearing units are increasing day by day, and they have developed to the third generation: the first generation is composed of double-row angular contact bearings. The second generation has a flange on the outer raceway for fixing the bearing, which can simply be put on the axle and fixed with nuts. This makes the maintenance of the car easier. The third generation of wheel hub bearing units uses the bearing unit and the anti-lock brake system ABS. The wheel 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 wheel hub bearings or wheel hub units will cause your vehicle to fail inappropriately and costly while driving, and even cause harm to your safety.

Please pay attention to the following matters when using and installing wheel hub bearings:
1. In order to ensure safety and reliability to the greatest extent possible, it is recommended that you check the wheel hub bearings frequently regardless of the age of the vehicle - pay attention to early warning signs of bearing wear: including any friction noise when turning or abnormal deceleration of the suspension combination wheel when turning. For rear-wheel drive vehicles, it is recommended to lubricate the front wheel hub bearings after the vehicle has traveled 38,000 kilometers. When replacing the brake system, check the bearings and replace the oil seals.

2. If you hear noise coming from the wheel hub bearing part, first of all, it is important to find the location where the noise occurs. There are many moving parts that may produce noise, or some rotating parts may come into 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 that cause the failure of the bearings on both sides of the front wheel hub are similar, it is recommended to replace them in pairs even if only one bearing is broken.

4. Wheel hub bearings are relatively sensitive and require the correct method and appropriate tools in all cases. During storage and installation, the bearing components cannot be damaged. Some bearings require greater pressure to be pressed in, so special tools are required. Be sure to refer to the car manufacturer's manual.

5. When installing bearings, they should be installed in a clean and tidy environment. Small particles entering the bearings will also shorten the service life of the bearings. It is very important to maintain a clean environment when replacing bearings. It is not allowed to hit the bearings with a hammer, and be careful not to drop the bearings on the ground (or similar improper handling). The condition of the shaft and the bearing seat should also be checked before installation. Even slight wear can lead to poor fit, which will cause early failure of the bearing.

6. For the hub bearing unit, do not attempt to disassemble the hub bearing or adjust the seal of the hub unit, otherwise the seal will be damaged and water or dust will enter. Even the seal and the raceway of the inner ring are damaged, causing permanent failure of the bearing.

7. The seal of the bearing equipped with ABS device has a magnetic thrust ring inside. This thrust ring cannot be hit, impacted or collided with other magnetic fields. Take them out of the box before installation and keep them away from magnetic fields, such as motors or power tools used. When installing these bearings, observe the ABS alarm needle on the dashboard through road condition tests to change the operation of the bearing.

8. For wheel hub bearings equipped with ABS magnetic thrust rings, in order to determine which side the thrust ring is installed on, you can use a small light object close to the edge of the bearing, and the magnetic force generated by the bearing will attract it. When installing, point the side with the magnetic thrust ring inward, facing the sensitive element of the ABS. Note: Improper installation may cause the brake system to fail.

9. Many bearings are sealed, and such bearings do not need to be greased during their entire life. Other unsealed bearings such as double-row tapered roller bearings must be greased during installation. Due to the different sizes of the inner cavity of the bearing, it is difficult to determine how much grease to add. The most important thing is to ensure that there is grease in the bearing. If there is too much grease, when the bearing rotates, the excess grease will seep out. General experience: During installation, the total amount of grease should account for 50% of the bearing clearance.

10. When installing the locking nut, the torque varies greatly due to the different bearing types and bearing seats.

If you need any brand bearings or any models of bearings, please contact me! Contact: Grace Email: ntn@llhbearing.com Skype:+8618668903871 MP/Whatsapp: +8618668903871 Wechat:GraceXu1234