Wheel hub bearing
Wheel hub bearing is one of the key parts of car, its main function is carrying weight and provide accurate guide to the rotation of the wheel hub, which requires not only can it carry axial load to bear radial load.
The Chinese name hub bearing type bearing type bearing USES the axial load and the radial load.
1 related background
2. Development history
3. Technology and development trend.
High performance sealing ring.
The amount of light miniaturization.
Low friction torque.
Forced the ABS technology
Traditional car wheel with bearing is combined by two sets of tapered roller bearings or ball bearings, and the installation of the bearing, oil seal and clearance adjustment is carried out on the auto production line. This structure makes it difficult to assemble, high cost and poor reliability in the automobile production plant, and it needs to be cleaned, greased and adjusted when the car is maintained at maintenance point.
Hub bearing unit.
Is in the standard angular contact ball bearings and tapered roller bearings, developed on the basis of it will be two sets of bearing as a whole, has the assembly clearance adjustment performance is good, can be omitted, light weight, compact structure, large load capacity, for the sealed bearing prior to loading, ellipsis external wheel grease seal and from maintenance etc, and has been widely used in cars, in a truck also has a tendency to gradually expand the application.
The development course
The wheel hub bearing of the car used to be used in pairs with single row taper roller or ball bearing. With the development of technology, cars have been widely used in car hub units. The use range and usage of hub bearing unit has been increasing, and now it has reached the third generation:
The first generation is composed of two - row angular contact bearings.
In the second generation, there is a flange for the bearing to be fixed, which can be easily fixed with the nut on the axle. Make car maintenance easy.
The third generation hub bearing unit is equipped with the bearing unit and the anti-lock brake system ABS. The hub unit is designed to have inner flange and outer flange. The inner flange is bolted to the drive shaft, and the outer flange will install the whole bearing together.
Fourth generation hub bearing.
Fourth generation wheel hub bearing unit is the patterned constant speed universal joint with the bearing into a whole, because hub in solves the existing technologies and patterned constant speed universal joint so that the size of the wheel weight increase caused by faults. The development of the fourth generation hub bearing unit has been successful, and it is believed that it will be widely used in all kinds of automobiles in the near future. The unit product features are: do not need to adjust the bearing assembly clearance, bearing assembly process more reasonable, weight reduced volume, one-time almost permanent use after fat, reduce the cost of the whole production, more conducive to large-scale popularization.
Technology and development trends.
High performance sealing ring.
Because hub bearing is very close to the ground and high temperature brake disc and other parts, it needs to adapt to various complicated road conditions and poor driving environment. Therefore, the bearing sealing ring must have good anti-leakage performance, and must have good heat resistance, mud and sewage.
Roll rolling technology
The third generation wheel hub bearing generally used shake self-locking half inner ring rolling technology, axial load when the wave rolling technology make the wheel spindle end produces plastic deformation, so as to make the wheel spindle and half inner ring connected into one. Compared with the traditional nut fastening, the third generation wheel bearing of rolling technology is used to reduce the volume and weight, while reducing the cost and improving the reliability of the hub bearing. At the same time, the steps to adjust the position of the internal parts are removed when assembling the car.
Second and third generation wheel hub bearing all must carry on the finite element analysis and structure design in guarantee flange rigid enough at the same time as far as possible, reduce the volume and weight of the third generation wheel hub bearing rigidity of the relative outer ring flange hub flange Angle. Through integration and miniatinization design to reduce the weight of the axle, the second generation hub bearing reduced 180g from the first generation, while the third generation hub bearing further reduced the weight of 120g.
Low friction moment
Important measure to reduce automobile fuel consumption is to design low friction torque of the wheel hub bearings, and the main factors influencing the bearing friction torque is the type of bearing and pre-tightening load, bearing seal and of friction torque caused by the large proportion in the composition. Therefore, improving the sealing design to reduce the friction torque can significantly improve the performance of the hub bearing. The wheel hub bearing is developed from the first generation to the newest fourth generation, and the friction torque is gradually reduced.
ABS is a kind of has the advantages of antiskid, antilock car safety control device, in the car when the emergency brake through detection of wheel speed, automatically adjust the braking force to prevent wheel lock, shorten braking distance. The speed detection is carried out by means of a magnetic sensor mounted on a part that is rotated along the wheel and fixed on the vehicle. The hub unit with ABS sensor is divided into two situations: one is placed inside the hub and the sensor is mounted on other parts; The other is to be placed inside the hub with the sensor (known as the sensor hub unit).
Matters needing attention
Hub bearing or wheel hub bearing wear or damage to wheel hub will cause undesirable and costly failure of your vehicle on the road, and may even cause damage to your safety. Please note the following items in the use and installation of hub bearing:
1, in order to ensure maximum security and reliability, it is recommended that you no matter how long vehicles will check regularly whether the wheel hub bearing, pay attention to the bearing wear of the early warning signs: including any rotating friction noise or hanging abnormal combination wheel in turn.
It is recommended that the rear wheel drive vehicle should be lubricated with the front wheel bearing for driving to 38,000 km. When changing the braking 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, or some of the rotating parts that are in contact with the non-rotating parts. If the noise in the bearing is confirmed, the bearing may be damaged and needs to be replaced.
3. Because the working conditions of the bearing failure on both sides of the front wheel are similar, it is suggested to replace them in pairs even if only one bearing is broken.
4. The hub bearing is sensitive, and in any case, the correct method and appropriate tools are needed. In the process of storage and installation, the bearing parts shall not be damaged. Some bearings require greater pressure, so special tools are needed. Be sure to refer to the car manufacturer's manual.
5. When installing the bearing, it should be in a clean and tidy environment. Small particles entering the bearing will also shorten the service life of the bearing. It is very important to keep a clean environment when changing bearings. Do not use a hammer to hit the bearing, and be careful not to fall on the ground (or a similar mishandling). Before installation, check the condition of the shaft and bearing pedestal. Even minor wear can lead to poor coordination, which can lead to the early failure of the bearing.
6. For the hub bearing unit, do not attempt to disassemble the hub bearing or adjust the sealing ring of the hub unit, otherwise the sealing ring will be damaged and lead to the entry of water or dust. Even the sealing ring and inner ring raceway are damaged, causing permanent failure of the bearing.
7. There is a magnetic thrust ring in the sealing ring of the bearing of the ABS device, which can not be bumped, impacted or collided with other magnetic fields. Remove from the box before installation and keep them away from the magnetic field, such as motor or power tools used. When these bearings are installed, use the road condition test to observe the ABS alarm needle on the dashboard to change the operation of the bearing.
8, equipped with ABS wheel hub bearing of magnetic thrust ring, in order to determine the thrust ring pack what side, use a light small things * close bearing the edge of the bearing of magnetic force will be attracted to it. When installing, one side of the magnetic thrust ring is pointed inside, and the sensor is sensitive to ABS. Note: incorrect installation may result in failure of the braking system.
9. Many bearings are sealed, and this type of bearing is not required to be greased for the whole life. Other unsealed bearings, such as double-row tapered roller bearings, must be greased when installed. Because of bearing inner cavity size is different, so it is difficult to determine how much oil is the most important is the guarantee of bearing grease, if excess oil, when bearing rotation, excess oil will seep. General experience: at the time of installation, the total amount of grease is 50% of the clearance of the bearing.
10. When the locking nut is installed, the torque varies greatly due to the different bearing type and bearing seat. Pay attention to the relevant instructions.
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