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What are the measures to improve the quality of bearing inspection

Update:27-01-2021
Summary:

Bearings are important components in vehicles and play […]

Bearings are important components in vehicles and play a vital role in the operation of vehicles. In many cases, vehicle bearings will have certain failures. Let's analyze the typical failure of vehicle bearings-peeling phenomenon.

1. Typical fault of vehicle bearing-peeling phenomenon.

After disassembling the faulty bearing, it was observed that the working surface of the bearing roller was peeled off, but the edge of the roller fell off. The working surfaces of the inner and outer rings of the bearing also produced metal flakes, and the working surfaces of the inner and outer rings in contact with the edge of the roller also appeared pits, which were distributed in a circle. The bearing cage has also been severely damaged and fractured, and plane scars have appeared on the plane of the cage.

2. Cause analysis of bearing failure

Analyzing the damage characteristics of the bearing, the basic reasons for the bearing failure mainly include the following aspects:

1) Contact fatigue damage.

2) The bearing is subjected to abnormal loads such as excessively high contact load or impact load, for example, the hot metal truck receives a large impact load during desulfurization or tank lifting; or the hot metal truck receives excessively high contact when the heavy tank passes through a curve. The role of load.

3) Improper assembly of the bearing or too small clearance causes excessive contact stress between components.

4) Poor lubrication. Due to the harsh maintenance environment of metallurgical enterprises, foreign matter such as iron slag, cotton yarn, dust, etc. was mixed into the lubricant during bearing maintenance.

3. Measures to improve the quality of bearing inspection

1) Appropriate selection of bearing clearance

Clearance is an important factor for the normal operation of rolling bearings, which is divided into axial clearance and radial clearance. Choosing a proper clearance can make the load reasonably distributed between the bearing rolling elements, limit the axial and radial displacement of the shaft (or housing), and ensure the rotation accuracy of the shaft; it can make the bearing work normally at the specified temperature; Reducing vibration and noise will help increase the life of the bearing. Therefore, when selecting a bearing, an appropriate bearing clearance must be selected. When selecting bearing clearance, the working conditions of the bearing, such as load, temperature, speed, etc., should be considered.

2) Improve bearing assembly quality

①Selection and measurement link: When assembling the bearing, making the correct selection is an important factor to ensure reasonable bearing clearance. However, the current measurement methods and tools are very simple and it is impossible to accurately select the bearing, so it is recommended Purchase the current more advanced measuring tools; after the bearing is assembled, the clearance measurement process is required. However, it has not been implemented due to the limitations of tools and measurement technology. It is recommended to add this process.

② Operation inspection link: After the bearing is installed, it should be checked to ensure that the bearing is installed in place, rotates flexibly, and has no blocking phenomenon. If the bearing is installed improperly, the temperature of the bearing will rise rapidly and be damaged, and even major accidents such as bearing blockage and fracture may occur. It is recommended to increase bearing running and inspection procedures.

 

 

3) Improve bearing maintenance and storage environment

① Maintenance environment: Due to the special nature of the maintenance environment of metallurgical enterprises, there are a large amount of iron powder and dust in the maintenance environment. Therefore, when the bearing is overhauled, the surrounding environment should be kept clean, and hand sweat and dirt should not be stuck.

②Storage environment: Bearings must not be stored directly on the ground (above 30cm from the ground), avoid direct light and cold walls. To prevent rust, store in an environment with a temperature of about 20°C and a humidity of 65% or less. Bearings placed in acidic air are prone to rust and discoloration. Therefore, it is necessary to strengthen bearing storage management to ensure that new bearings are not damaged by external factors.

4) Standardized disassembly and assembly of axle boxes

At present, bearing maintenance work is relatively extensive, especially in the process of axle box disassembly and assembly, sometimes using a sledge hammer to strike, which may cause internal damage to the bearing and shorten the working life of the bearing. Therefore, while strengthening the management of bearing maintenance, it is necessary to Actively understand the situation in the front line, make effective improvements to the problems found, develop corresponding maintenance tools, and improve the quality of bearing maintenance.

5) Eliminate the loading of inferior bearings at the source

①External packaging inspection: Under normal circumstances, the factory brand has its own dedicated designers to design external packaging, and arrange for production in factories that pass the production conditions. Therefore, the packaging is very clear from lines to color blocks.

②Steel printing inspection: usually the brand words, labels, etc. are printed on the bearing body with very small fonts. However, most of the products produced by the factory use steel stamping technology, and the characters are pressed before heat treatment. Therefore, although the font is small, it is deeply concave and very clear. The fonts of counterfeit products are not only blurred, but also the printing technology is rough, the fonts float on the surface, and can even be easily erased by hand.

③Rotation inspection: Hold the inner sleeve of the bearing with your left hand, and turn the sleeve with your right hand to listen for noise. Due to the backward production conditions of most counterfeit products, or even completely manual workshop operation, it is inevitable that sundries such as sand will be mixed in the bearing body during the production process, so noise will be made when rotating. This is the biggest difference from a genuine brand that strictly enforces production standards and operates with machines.

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