Causes of corrosion of bearing products

The main causes of corrosion are as follows:

    1. In the process of producing bearings, some enterprises did not strictly carry out anti-rust treatment on the bearing parts in the processing process and the finished bearing products in accordance with the requirements of cleaning anti-rust regulations and oil seal anti-rust packaging. If the ferrule has a long turnaround time during the turnaround, the outer ring of the outer ring is exposed to corrosive liquid or gas.

    2. The quality of anti-rust lubricating oil and cleaning kerosene used by some enterprises in production cannot meet the requirements of process technology.

    3. As the price of bearing steel drops and then falls, the bearing steel material gradually declines. For example, the content of non-metallic impurities in the steel is too high (the increase in sulfur content in the steel causes the corrosion resistance of the material itself to decrease), the metallographic structure deviation, and the like. The source of bearing steel used in production companies is more complicated, and the quality of steel is even more.

    4. Some enterprises have poor environmental conditions, high levels of harmful substances in the air, and too little turnover space, making it difficult to carry out effective anti-rust treatment. Coupled with the hot weather, production workers violated anti-rust procedures and other phenomena.

    5, some enterprises' anti-rust paper, nylon paper (bag) and plastic cylinder and other bearing packaging materials do not meet the requirements of rolling bearing oil seal anti-rust packaging is also one of the factors causing corrosion.

    6. The turning allowance and grinding allowance of the bearing ring of some enterprises are small, and the oxide scale and decarburization layer on the outer circle are not completely removed.

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What are the methods for removing common rolling bearings?

Commonly used disassembly methods for rolling bearings are: tapping method, pull-out method, pushing method, and hot-breaking method.

First, the tapping method

The tapping force is generally applied to the inner ring of the bearing. The striking force should not be added to the rolling element and the cage of the bearing. This method is simple and easy, but it is easy to damage the bearing. When the bearing is at the end of the shaft, it is smaller than the inner diameter of the bearing. A copper rod or other soft metal material is placed against the shaft end, and a pad is placed at the lower part of the bearing, and the hammer is gently tapped with a hammer to remove it. Applying this method should pay attention to the position of the pad to be placed properly, and the focus should be correct.

Second, the pull out method

A special puller is used. When disassembling, the bearing will be pulled out slowly as long as the handle is rotated. When the outer ring of the bearing is disassembled, the angle of the two legs of the puller should be opened outwards; when the inner ring of the bearing is removed, the two legs of the puller should be inward and snapped onto the end face of the inner ring of the bearing.

  Precautions:

1. The pull hook of the puller should be hooked on the inner ring of the bearing, and should not be hooked on the outer ring to avoid excessive looseness or damage of the bearing;

2. When using the puller, align the screw to the center hole of the shaft and do not skew. Should also pay attention to the force of the hook and the bearing, do not damage the hook and bearing;

3. Pay attention to prevent the hook from slipping off;

4. The angle of the two legs of the puller is less than 90°.

Third, push method

The bearing is pressed by the press, and the work is stable and reliable without damaging the machine and the bearing. The press has manual pushing, and the mechanical or hydraulic press pushes.

Note: The pressing point of the press should be on the center of the shaft and should not be biased.

Fourth, hot demolition

Used to remove the tight fit bearing. First, the oil heated to about 100 °C is poured into the bearing to be dismantled. After the bearing ring is thermally expanded, the bearing can be pulled out with a puller.

  Precautions:

1. First, the puller should be installed on the bearing to be removed and a certain pulling force should be applied;

2. Before heating, the shaft should be wrapped with asbestos rope or thin iron plate to prevent the shaft from being swollen by heat. Otherwise, it will be difficult to disassemble. When the bearing is removed from the bearing housing hole, only the bearing housing hole can be heated and cannot be heated. Bearing

3. When pouring oil, the oil pot should be smoothly poured on the bearing ring or the rolling element, and an oil basin should be placed under it to collect the hot oil flowing down to avoid waste and burns;

4. Operators should wear asbestos gloves to prevent burns.

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Causes, phenomena and treatment methods of bearing temperature rise

1. Reasons for the increase in bearing temperature:

    (1). Bearing cooling water is interrupted.

    (2). The oil quality is degraded, the oil itself is not clean or the oil is degraded during operation. If the water in the oil increases, the acidity of the oil will increase, the lubricating effect of the oil will be reduced, the bearing bush will be corroded, and the bearing temperature will rise.

    2. Phenomenon:

    (1). There is an alarm bell ringing.

    (2). The machine side water wheel mechanical fault light plate is on, the temperature of the instrument indicating the bearing temperature rises, and the signal relay operates.

    (3). Thermometer disk (inflated thermometer) The black needle and the yellow needle overlap or exceed the yellow needle.

    (4). A fault signal that raises the bearing temperature.

    3. Processing

    When the bearing temperature rises, first judge whether it is malfunctioning. If it does rise, it should be treated as follows:

    (1). Check the cooling water pressure, water flow and piping system is normal. If the water pressure is low, the filter may be clogged and cannot be disposed of in time. It can be shut down and put into use when it is confirmed that it can work.

    (2). Check the oil pressure of the governor. If the oil pressure is low, the cooling water hydraulic valve may be closed.

    (3). Check if the bearing has abnormal sound and check if the bearing swing is abnormal.

    (4). Observe the oil sample to see if there is any change in the oil color, and test it to see if it has deteriorated. If deterioration is confirmed, stop replacing the new oil.

    (5). Check if the oil level is normal. If it is not normal, check if the oil drain valve is closed. If it is closed, it should be replenished. If the gasket is oily, it should be stopped.

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Locomotive rolling bearing fault generation and diagnosis method

 Locomotive rolling bearing fault generation and diagnosis method

    Abstract: This paper introduces the simple diagnosis and precision diagnosis of locomotive rolling imported bearings, and enumerates the detection cases.

    Key words: locomotive rolling imported bearing fault detection
   
    1 Introduction

    As the main components of the locomotive, especially the traction motor and axle box bearing, the imported function plays a decisive role in the safe transportation. When the locomotive runs on the line, once the bearing fails, the whole train will not run, and the transportation line will be blocked. In particular, the passenger trains fail, and the negative impact is even greater. At the same time, once the locomotive bearings fail, it is very difficult to repair the locomotives. Therefore, preventing and reducing the occurrence of locomotive bearing faults is very dangerous for the safe transportation of locomotives. It is important to be able to detect the bearing with hidden troubles before the bearing is loaded, and to ensure that the qualified bearing accessories are on the car is the focus of this paper.

    2 bearing failure

    Severe damage of the bearing is often not caused by a single cause. However, under a combination of several aspects, a vicious cycle occurs under severe operating conditions, resulting in serious burning of the bearing. Therefore, after an accident, it is often difficult to judge What causes it, it also gives us some difficulties in formulating relevant measures. For the convenience of discussion, we first analyze the causes of bearing failures from several aspects.

    2.1 Abnormal wear of the bearing

    2.1.1 When the bearing is used for a period of time, the bearing inner ring, rolling element, cage, outer ring, raceway, etc. will produce certain defects and scars, resulting in poor lubrication of the bearing, causing heat generation of the bearing, long-term heating, resulting in:

    (1) Dilution of bearing lubricants.

    (2) Accelerate the fatigue of the material and reduce the hardness. Due to the above reasons, a vicious cycle is further formed, and the overheating is accelerated to burn the bearing. Severe bearing inner ring displacement, rolling element out of round, collision heat, and finally welded together. Therefore, when running on the line, if the bearing is found to be severely heated and smokes, do not stop, but keep running to the front station, because the overheated bearing is in a molten state at this moment, once it stops cooling, it can no longer walk and block the positive line.
 
    2.1.2 It is very important for the oil supply maintenance of locomotive bearings, especially for the proper amount of oil to ensure that the bearing has good lubrication. It is easy to cause bearing failure due to lack of oil and excessive oiling. Poor lubrication and heat, more often it is easy to cause stirring and overheating, so it is necessary to properly supply oil during maintenance, and the lubricating grease of the bearing is also very important. Once the oil and other impurities and moisture are dropped, it will affect the normal swimming. Gap and build the necessary oil film.

    2.1.3 The bearing is used for too long, which exceeds the service life of the bearing and is prone to fatigue of the material. The strong impact of the material causes the material to deform, causing the roller and the raceway surface to peel off and crush, resulting in poor lubrication. And the vibration is increased.

    2.2 Installation impact on bearings

    2.2.1 The inner clearance of the inner ring of the bearing does not match the interference of the shaft. It is also easy to cause bearing failure. The interference is large. It is easy to cause the inner ring of the bearing to crack due to excessive tensile stress. The interference is too small. It is easy to cause the inner ring of the bearing to "relax".

    2.2.2 Bearing assembly with improper clearance, it is easy to cause bearing failure, small clearance is easy to cause friction between the roller and the raceway. As the temperature rises, the bearing inner ring, rolling element, cage, outer ring The temperature of the end caps is not the same, there is a temperature difference between them, so the amount of expansion is also slightly different, which causes a further reduction of the matching clearance, and the heat generation of the bearing is added. If the clearance is too large, the vibration of the roller is increased, which aggravates the impact of the roller and the raceway. At the same time, the internal load distribution is uneven, the load bearing roller is reduced, and the central roller load is excessive.

    2.2.3 When assembling the bearing, the bearing is not impacted by the copper hammer, which causes the cage to be deformed. The inner and outer rings of the traction motor bearing are not installed correctly or other reasons cause the axial traverse amount to disappear, causing the bearing shaft to squash.

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