Research on the working principle and abnormal noise of automobile hub bearing
With the increase in customer requirements for automobile comfort, the problem of automobile abnormal noise is more and more complained by people. How to quickly lock the source of abnormal noise from many noise sources and eliminate the abnormal noise has become an important problem in automobile maintenance. Among them, the hub bearing has a certain service life as a key component of automobile load and travel. Once a failure occurs, it will produce a disturbing abnormal noise. The abnormal noise of the hub bearing is also a common failure in after-sales maintenance. Based on the working principle of the hub bearing and the characteristics of its abnormal noise, this article provides a method for the rapid diagnosis of the abnormal noise of the hub bearing, which can be used as a reference for the diagnosis of the abnormal noise of the hub bearing.
1. Working principle of hub bearing
Hub bearings can be divided into first, second and third generation hub bearings according to the structure. The first generation of hub bearings is mainly composed of inner ring, outer ring, steel ball, and cage. Its working principle is shown in Figure 1. The working principles of the first-, second-, and third-generation wheel bearings are similar to ordinary bearings. They use steel balls to roll in the inner ring, outer ring, or flange raceway, load and rotate relatively, so that the car runs.
2. Abnormal sound of hub bearing
1. Characteristics of hub bearing abnormal noise
According to the working principle and stress characteristics of the hub bearing, its abnormal noise has three important characteristics: ① The hub bearing rotates with the wheel, and the frequency of the abnormal noise is proportional to the wheel speed. As the vehicle speed increases, the abnormal noise of the hub bearing continuously becomes stronger. Generally, the abnormal noise only occurs in a narrower speed section. ②The abnormal noise strength of the hub bearing is proportional to the load it bears. When the car turns, the hub bearing bears a large load, and the abnormal noise is more obvious. ③ The abnormal noise of the hub bearing is easily confused with the abnormal noise of the transmission systems such as tires, engines, transmissions, transmission shafts, and universal joints.
2. The manifestation of abnormal noise of hub bearing
There are three main forms of abnormal noise in hub bearings:
The inner raceway of the hub bearing has defects such as wear, flaking, and indentation, or when the bearing is loose, it will continue to produce "gurgling" and "humming" abnormal noises. As the vehicle speed increases, the periodic grunt gradually turns into a buzzing sound, and when driving at a high speed, it gradually turns into a high-frequency whistling sound.
When the seal of the hub bearing fails, when the amount of internal grease is insufficient, the grease cannot form an oil film on the surface of the channel and the steel ball, causing contact friction between the channel and the surface of the steel ball, resulting in a sharp squeak.
When there are knock bumps on the surface of the steel ball inside the bearing, cracking of the steel ball, and the presence of hard foreign objects inside the bearing, the steel ball crushes the abnormal part of the raceway during driving, resulting in a "scream" abnormal noise.
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