Research on the working principle and abnormal noise of automobile wheel hub bearing

With the improvement of customers' requirements for automobile comfort, more and more people complain about the abnormal noise of automobiles. How to quickly lock the source of abnormal noise from many noise sources and eliminate abnormal noise has become an important issue in automobile maintenance. Among them, the wheel hub bearing, as a key component for automobile load-bearing and driving, has a certain service life. Once it fails, it will produce annoying abnormal noise. The abnormal noise of the wheel hub bearing is also a common fault in after-sales maintenance. Based on the working principle of hub bearing and its abnormal sound characteristics, this paper provides a method for the rapid diagnosis of abnormal sound fault of hub bearing, which can be used as a reference for the diagnosis of abnormal sound fault of hub bearing.

Working principle of 1. hub bearing

Wheel hub bearings are divided into first-generation, second-generation and third-generation wheel bearings according to their structural forms. The first-generation wheel hub bearing is mainly composed of inner ring, outer ring, steel ball and cage. Its working principle is shown in Figure 1. The working principle of the first, second and third generation wheel bearings is similar to that of ordinary bearings. They all use steel balls to roll in the inner ring, outer ring or flange raceway to carry and rotate relative to each other, so that the car can run.

Abnormal sound of 2. hub bearing

1. Abnormal noise characteristics of hub bearing

According to the working principle and force characteristics of the wheel hub bearing, its abnormal noise has three important characteristics: ①The wheel hub bearing rotates with the wheel, and the abnormal noise frequency is proportional to the wheel speed. As the vehicle speed increases, the abnormal noise of the wheel hub bearing continuously becomes stronger, and generally there will be no abnormal noise only in a narrow vehicle speed range. ② The abnormal noise intensity of the hub bearing is proportional to the load it bears. When the car is turning, the wheel hub bearing bears a larger load, and the abnormal noise is more obvious. ③The abnormal noise of the wheel hub bearing is easily confused with the abnormal noise of the tire, engine, transmission, transmission shaft, universal joint and other transmission systems.

2. Forms of abnormal noise of wheel hub bearing

The main abnormal noise of wheel hub bearings is as follows:

(1) Hum

The internal raceway of the wheel hub bearing has defects such as wear, peeling, indentation, or when the bearing is loose, it will continue to produce "grunt" and "buzzing" abnormal noises. As the vehicle speed increases, the periodic grunt gradually turns into a buzzing sound, and when driving at high speed, it gradually turns into a high-frequency whistling sound.

(2) Squeaking

When the hub bearing seal fails and the amount of internal lubricating grease is insufficient, the grease cannot form an oil film on the surface of the channel and the steel ball, resulting in contact and friction between the channel and the steel ball surface, resulting in a sharp squeak.

(3) Goggle

When there are bumps on the surface of the steel ball inside the bearing, the steel ball is broken, and there are hard foreign objects inside the bearing, the steel ball rolls the abnormal part of the raceway during driving, resulting in "flickering" abnormal noise.