Damage and maintenance of automobile front wheel rolling bearings

Automobile front wheel bearings work under high temperature, high speed and high load conditions for a long time. After being used for a long time, they are prone to wear, ablation, spots, cracks and fatigue peeling, and early damage occurs.

The damage form of the front wheel rolling bearing of the automobile is: the contact pressure of the working surface of the bearing is too large, the surface wear and fatigue peeling of the bearing are affected, the damage increases the axial and radial clearance of the bearing, generates noise during work, and destroys other Fit the correct position of the bearing. The wear under normal use conditions is not large, but when the sediment or hard particles invade the bearing and the lubrication is insufficient or the lubricant is deteriorated, it is easy to cause sharp wear, increase the rolling surface clearance, deform, and damage the bearing and related parts. The normal work caused the roller of the rolling bearing to rupture, scratch, and loosen the spacer.

The assembly and adjustment of the bearing are not good. In particular, when the seat ring is mounted on the shaft, the method is too tight. The method of disassembly and assembly is not proper, and the friction and wear are caused during work, so that the rolling element looses and falls off, and the bearing is crushed. The bearing burns discolored or rusted. When the bearing is running, the heat is annealed by high temperature, and the surface is discolored. The bearing surface is oxidized and rusted due to insufficient addition of lubricating oil or deterioration of the lubricating oil. The rolling surface is often subjected to alternating pressure, which often causes the metal to fatigue and cause peeling.

Its service life is affected by many factors such as the selection of various parts and materials, heat treatment specifications, cold working precision, and assembly adjustment. Due to poor management of a small number of bearing manufacturers, the products failed to meet the technical standards of the bearings themselves. If the material is not properly selected, the heat treatment specifications are not strict, the machining is too poor, the size of the roller body is different, and the inner and outer raceways are not matched, etc., it will cause early damage of the bearing. Once the bearing roller and the raceway are sintered, firstly, the individual roller rotation is blocked and skewed, causing all the rollers to be skewed to wedge the inner and outer rings, and the hub bearing and the steering knuckle are integrated, causing the knuckle neck to break.

Common causes of early damage to automotive front-wheel rolling bearings are: First, improper assembly adjustment. There are clearance regulations in the technical conditions of bearing products, which is the axial clearance necessary to ensure lubrication during normal bearing operation, which is easy to attract people's attention. However, the gap is too tight, too small or no gap is often ignored, which is the cause of the initial failure: on the one hand, due to the oil film between the roller and the raceway is destroyed, forming dry friction, heat, local high temperature, causing plastic deformation Causes the bearing to sinter. On the other hand, due to poor lubrication, dry friction also occurs between the roller and the raceway, causing the bearing to sinter. The second is the quality of the bearing itself. Bearings are a complex combination of many parts.

When inspecting and certifying the front wheel rolling bearing of a car, first remove it and clean it. Appearance inspection of the ball, raceway and spacers for defects, and then use the hand to idling, to hear the sound of uneven sound, whether it is free to rotate, smooth without jam and light and flexible without abnormalities, then use the meter to measure the bearing spacing, and finally Comprehensively identify whether the quality is reliable and can be used normally. The degree of wear of the rolling bearing is mainly determined by the radial clearance. Press the inner race of the bearing and push the outer race by hand. The swing indicated by the dial gauge is the radial clearance of the bearing.

The measurements should be taken in several different directions and then averaged. If the gap exceeds the specification limit, it will be scrapped. Bearing wear and looseness can also be checked during machine operation, based on the sound of the bearing. The larger the gap, the higher the speed and the stronger the noise emitted by the bearing. When the rolling element and the raceway face are rusted, corroded, peeled off, scratched or broken, in addition to noise, there is also an irregular impact sound. If the bearing is disassembled many times, the seat ring and related parts will be worn. In this case, it is best to take technical measures or replace the new one.