Everything you want to know about wheel bearings is here

Bearing, known as the cornerstone of the industry, its importance is beyond doubt.

There are tens of thousands of parts in a car, and there are bearings where there are rotating pairs. There are dozens of bearings inside the engine gearbox.

It looks like this.

Don't go away in a hurry. This bearing usually hides deeply. People don't often see it on the surface.

If you are particularly curious and just want to know where it is, what should you do?

Don't worry, there is a way.

A picture is better than the preface. Look at the picture.

The wheel bearing is the part that connects the tire and the steering knuckle. Its main function is to reduce friction for the rotating pair. And at the same time it also plays a role in transmitting force. It bears a very large radial load and axial load.

Wheel bearings include ball bearings and tapered roller bearings.

The main difference lies in whether the shape of the rolling medium is spherical or conical.

Unless it is a particularly heavy-duty vehicle, generally the wheel bearings of passenger cars are ball bearings.

Are there any classifications of ball bearings?

You may have noticed. There are three types of bearings in the previous bearing picture, namely first-generation bearings, second-generation bearings and third-generation bearings.

What is the difference between these three types of bearings?

First-generation bearing

The structure of the first generation of bearings is the simplest, mainly consisting of an inner ring, an outer ring, and steel balls. And the cost is the lowest.

Although the first-generation bearings have the advantages of simple structure and cost, they also have many disadvantages.

The first is the inconvenience of the assembly during the final assembly in the depot.

Since the first-generation bearings are independent of the steering knuckle and the hub, it is necessary to press-fit the inner ring of the bearing onto the hub and press-fit the outer ring of the bearing into the knuckle during online assembly.

Due to the complex assembly process, the requirements for equipment and process control are relatively high.

The second is poor performance.

Because the process cannot be precisely controlled during installation, 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 bearings, its output has been declining year by year, except that some car manufacturers are still using the first-generation bearings based on cost considerations. It will eventually disappear gradually (although I doubt it, because in this magical land of China, for the cost, the car factory can do everything, and it will be helpless).

Second-generation bearings

The structure of the second-generation bearing is slightly more complicated, and the wheel hub is integrated on the basis of the first-generation bearing.

Compared with the first-generation bearings, the process of pressing into the hub is omitted during assembly, but it also needs to be assembled with the steering knuckle for an interference fit, and the assembly accuracy is only slightly higher than that of the first-generation bearings.

However, it also has the disadvantage of poor performance.

At present, in addition to some car manufacturers still insisting on using them on the rear wheel hub, they are also used less and less like a generation of bearings, and eventually die out.

Three-generation bearings

As smart as you, you must have guessed it. Since the first and second generations are getting less and less, then the third generation of bearings must be the mainstream.

Bingo! You guessed it~

In terms of integration, the inner ring of the third-generation bearing is integrated with the hub, and the outer ring is integrated with the flange connecting the steering knuckle, which can be connected with the steering knuckle by bolts. The assembly accuracy is greatly improved.

And because all dimensions are precisely controlled by 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.

Fourth-generation bearings? Five-generation bearings?

At present, many people in the industry are also studying solutions for further integration. Someone proposed the concept of the fourth-generation bearing, which is to integrate the third-generation bearing with the constant velocity joint of the driving wheel. Someone also proposed the concept of the fifth-generation bearing, which is to integrate the bearing with the brake disc.
There should be no technical problems. As for whether it can be promoted, it depends on whether the market can accept it.