Misunderstanding of the use of lubricating grease during the repair process

Core tips: 1. Butting when installing the cylinder head gasket Some repairmen prefer to apply a layer of butter on the cylinder head gasket when installing the cylinder head gasket, which is considered to increase the engine's tightness. As everyone knows, doing this
 1. Butter when installing the cylinder head gasket

    Some repairers prefer to apply a layer of butter on the cylinder head when installing the cylinder head gasket, which is considered to increase the engine's tightness. As everyone knows, this is not only useless, but harmful. It is well known that the cylinder head gasket is an important sealing material between the engine block and the cylinder head of the automobile. It not only requires strict sealing of the high temperature and high pressure gas generated in the cylinder, but also must seal the pressure and flow rate through the cylinder head and the cylinder body. Cooling water and oil, it is required to pay special attention to the quality of the seal when disassembling the cylinder head gasket.

    If butter is applied to the cylinder head gasket, when the cylinder head bolts are tightened, a part of the butter will be squeezed into the cylinder water channel and the oil passage. When the butter remaining between the cylinder heads is working in the cylinder, some of the oil will flow into the cylinder due to the high temperature. The other part will burn the coke deposits on the joint surface of the cylinder block and the cylinder head. Under the action of high pressure and high temperature, it is easy to break down or burn through the cylinder head gasket, causing the engine to leak. Therefore, do not apply butter when installing the cylinder head gasket.

    2. Diesel car uses gasoline engine oil

    The oil is divided into gasoline engine oil and diesel engine oil. Although gasoline engines and diesel engines also work under high temperature, high pressure, high speed and high load conditions, there is still a big difference between the two. The compression ratio of the diesel engine is more than twice that of the gasoline engine. The main parts are much more affected by high temperature and high pressure than the gasoline engine, so some parts are made of different materials. For example, the gasoline engine main shaft and the connecting rod bearing bush can be made of babbitt alloy with soft material and good corrosion resistance, while the bearing bush of the diesel engine must be made of high-performance materials such as lead bronze or lead alloy, but the corrosion resistance of these materials Poor performance. For this reason, in the refining process of diesel engine oil, more anti-corrosion agent should be added, so that a protective film can be formed on the surface of the bearing pad to reduce the corrosion of the bearing bush and improve the wear resistance. Since the gasoline engine oil does not have such a preservative, if it is added to the diesel engine, the bearing bush is prone to spots, pits and even the unfavorable consequences of peeling off during use, and the oil will quickly become dirty and cause the shaft to burn. The accident occurred. In addition, the sulfur content of diesel oil is larger than that of gasoline. This harmful substance will form sulfuric acid or sulfurous acid during the combustion process, and together with the high-temperature and high-pressure exhaust gas, it will enter the oil sump to accelerate the oxidation and deterioration of the oil, so the diesel engine oil is refined. Some anti-oxidation additives need to be added during the process to make the oil alkaline. If there is acid gas intrusion, it can play a certain neutralization effect, so as not to cause the oil to oxidize and deteriorate too quickly. The gasoline engine oil does not add this additive because it is neutral. If it is used in a diesel engine, it will quickly deteriorate due to the corrosion of the above acid gas. Therefore, do not use gasoline engine oil to fill the diesel engine.

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Locomotive rolling bearing fault generation and diagnosis method

Core Tips: The locomotive rolling bearing fault generation and diagnosis method summary: Introduce the simple diagnosis and precision diagnosis of the rolling bearing of the locomotive, and enumerate the detection cases. Key words: locomotive rolling import
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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