Wheel hub bearings are divided into ball bearings and tapered roller bearings.
The difference mainly lies in whether the shape of the medium (roller) rolling inside is spherical or conical.
Unless it is a vehicle with a particularly large load (engineering vehicles and large SUVs, pickups, etc.), the wheel hub bearings of passenger cars are generally ball bearings.
What is the difference between these three bearings?
The structure of the first-generation bearing is the simplest, mainly consisting of an inner ring, an outer ring and steel balls. And the cost is also the lowest.
Although the first-generation bearing has the advantages of simple structure and cost, it also has many disadvantages.
The first is the inconvenience of assembly during final assembly in the depot.
Since the first-generation bearing is independent of the steering knuckle and the hub, during online assembly, the inner ring of the bearing needs to be press-fitted to the hub (Hub), and the outer ring of the bearing needs to be press-fitted into the steering knuckle (Knuckle).
Due to the complex assembly process, the requirements for equipment and process control are high.
The second is poor performance.
Since the installation process cannot be precisely controlled, the performance deviation of the bearing after press-fitting is also large, and the overall performance is low.
Due to the above shortcomings of the first-generation bearing, its production has declined year by year, except that some car manufacturers still use the first-generation bearing for the front wheel hub bearing based on cost considerations.
The structure of the second-generation bearing is a little more complicated, and the hub is integrated on the basis of the first-generation bearing.
Compared with the first-generation bearing, the process of pressing the wheel hub is omitted during assembly, but an interference fit assembly with the steering knuckle is also required, and the assembly accuracy is only slightly higher than that of the first-generation bearing.
However, it also has the disadvantage of poor performance.
At present, in addition to some car manufacturers insisting on using it on the rear wheel hub, it is also used less and less like the first generation of bearings, and eventually died out.
The first generation and the second generation are getting less and less, so it must be the third generation bearing is the mainstream.
In terms of integration, the inner ring of the third-generation bearing is integrated with a hub (Hub), and the outer ring is integrated with a flange connecting the steering knuckle, which can be connected with the steering knuckle by bolts. Assembly accuracy is greatly improved.
And since all dimensions are precisely controlled at the supplier, the performance is the best.
Due to these two advantages, although the cost is slightly higher, the third-generation bearings are still favored by almost all mainstream car manufacturers.
Four generations of bearings? Five generations of bearings?
At present, many people in the industry are also studying further integration schemes. Some people put forward the concept of four generations of bearings, which is to integrate the three generations of bearings with the constant velocity universal joint of the driving wheel. Others have proposed the concept of a fifth-generation bearing, which integrates the bearing with the brake disc.
There should be no technical problems. As for whether it can be promoted or not, it depends on whether the market can accept it.
