Due to the influence of materials, processes, parts aging and human factors, construction machinery will inevitably have a variety of failures in use. However, if you can correctly analyze the causes of various failures, take effective and targeted preventive measures, and try to slow down the damage speed of mechanical parts, it can effectively prevent mechanical failures and extend the service life of machinery. (for reference only)
1, minimize the impact of harmful factors
(1) Reduce the impact of mechanical impurities
Mechanical impurities generally refer to non-metallic substances such as dust and soil and some metal chips and wear products generated by construction machinery itself in the process of use. Once these impurities enter the inside of the machine and reach the mating surface of the machine, the harm is very great, not only blocks the relative movement, accelerates the wear of the parts, but also scratches the mating surface, destroys the lubricating oil film, increases the temperature of the parts and deteriorates the lubricating oil. According to the measurement, when the mechanical impurities in the lubrication increase to 0.15%, the wear speed of the first piston ring of the engine will be 2.5 times larger than the normal value; When the rolling shaft enters the impurity particles, its life will be reduced by 80%-90%. Therefore, for construction machinery that works in harsh environments and complex conditions, it is necessary to use high-quality, supporting parts and lubricating oil and grease to block the source of harmful impurities; Second, we should do a good job of mechanical protection work at the work site to ensure that the corresponding mechanism can work normally and prevent various impurities from entering the mechanical interior. For the failure of the machinery, as far as possible to the regular repair site for repair. When on-site repair, it is also necessary to take protective measures to prevent the parts replaced during on-site repair from being contaminated by impurities such as dust before entering the machinery.
(2) Reduce the influence of temperature
In the work, the temperature of each component has its own normal range. For example, the temperature of the general cooling water is 80-90 ° C, and the temperature of the hydraulic oil of the hydraulic transmission system is 30-60 ° C, below or above this range will accelerate the wear of the parts, cause the deterioration of the lubricating oil, cause the material performance changes, and so on. The test shows that the main transmission gear and bearing of various construction machinery run in -5℃ lubricating oil than run in 3℃ lubricating oil, wear to increase 10-12 times. However, when the temperature is too high, it will accelerate the deterioration of the lubricating oil, such as when the oil temperature exceeds 55-60 ° C, the oil oxidation rate will be doubled for every 5 ° C increase in the oil temperature. To this end, during the use of construction machinery, first, to prevent overload operation at low temperatures, to ensure the normal operation of the low-speed pre-temperature stage, so that the machinery reaches the specified temperature before driving or working, do not ignore its important role because there is no problem at that time; Second, to prevent the machinery from operating at high temperatures, the mechanical operation process should often check the values on various thermometers, find the problem immediately shut down for inspection, find the fault in time to eliminate. For a time can not find the cause, must not be treated and still make the machine work with disease. In the usual work, pay attention to check the working condition of the cooling system. For water-cooled machinery, it is necessary to check and add cooling water before working every day; For air-cooled machinery, it is also necessary to regularly clean the dust on the air-cooled system to ensure that the cooling air duct is smooth.
(3) Reduce various corrosion effects
The phenomenon of metal surface and surrounding medium chemical or electrochemical interaction and damage is called corrosion. This corrosion will not only affect the normal work of the mechanical surface equipment, but also corrode the internal parts of the machinery. For example, rainwater and chemicals in the air enter the mechanical interior through the external channels and gaps of mechanical parts, corroding the internal parts of mechanical parts, accelerating mechanical wear and increasing mechanical failures. Because this corrosive effect is sometimes invisible and can not be touched, it is easy to ignore the vent, so it is more harmful. In use, management and operation personnel should take effective measures according to the local weather conditions and air pollution conditions at the time to reduce the impact of chemical corrosion on machinery, focusing on preventing the intrusion of chemical components in the rain and air on machinery.
2. Ensure normal working load
The size and nature of the working load of construction machinery have an important influence on the loss process of machinery. In general, the wear of parts increases proportionally with the increase in load. When the load on the part is higher than the average design load, its wear will be increased. In addition, when other conditions are the same, the stable load has less wear, less failure and lower life than the dynamic load. The test shows that the wear of the cylinder will increase by 2 times when the engine works under unstable load compared with stable load. An engine operating under normal load has a lower incidence of failure and a longer life. On the contrary, the overload operation of the engine, the incidence of failure is significantly increased, and the life will be reduced than the design index. The wear of machinery that is often subjected to a wide range of load changes is greater than that of continuously stable machinery. Under normal circumstances, the engine used by the generator has a longer life than that used by the bulldozer, excavator, etc.
To ensure the normal working load mainly depends on the operator's use of construction machinery. First, pay attention to not working under the maximum load that the machine can bear, and use the machine as far as possible. As a construction machinery manager, when appointing the operator, it is necessary to hand over the random information and operation manual of the construction machinery to the operator, so that it can normally master the mechanical properties and operating procedures, and should not be free to buckle down the relevant information. Second, we should try to ensure the uniform increase and decrease of mechanical load, so that the machinery is in a relatively smooth load change, specifically, it is to increase and decrease the throttle more evenly to prevent the fluctuation of the engine and the working device.
3, to ensure the reasonable lubrication of machinery
The grinding of parts working surface, the corrosion of parts surface and the aging of materials are the three main change forms of mechanical parts under normal use conditions, and the failure caused by the wear of parts working surface accounts for the largest proportion. In other words, the wear of the machinery is one of the main reasons for its various parts to the limit technical state. Then, solve the wear problem of mechanical parts. In addition to the use of excellent materials, the selection of advanced manufacturing processes, the design of reasonable mechanical structure, in the use of the process to do an important job is to ensure the reasonable lubrication of the machinery. According to statistics, more than half of the failures of construction machinery are caused by poor lubrication. Due to the precision of the construction machinery parts, good lubrication can make it maintain a normal working gap and a suitable working temperature, so as to reduce the degree of wear of parts and reduce mechanical failure. Normal and reasonable lubrication is one of the effective measures to reduce mechanical failure. To this end, the first is to choose a reasonable lubricant, according to the type of machinery and the different application structure of the normal lubricant category, according to the requirements of the machinery to choose the appropriate quality and other groups, according to the requirements of the machinery to choose the appropriate quality grade, according to the working environment of the machinery and different seasons to choose the appropriate lubricant brand. In use, neither low-grade lubricants can be used, nor other types of lubricants can be replaced, and inferior products can not be used. The second is to check the quantity and quality of lubricants frequently. Insufficient quantity should be supplemented in time, and poor quality should be replaced in time. Under emergency conditions, if different types and brands of lubricant are used as substitutes, the lubrication system must be cleaned and the normal lubricant replaced in time.
4, timely maintenance
Machinery in the use of the process will inevitably appear a variety of failures. In these failures, some of the impact on the mechanical equipment may be very small, some are more serious, and even cause a major accident. Experience has shown that serious mechanical failures are often triggered by minor failures. The reason lies in the neglect of the timely disposal of minor faults. Therefore, for mechanical failures, no matter the size, should be eliminated in a timely manner, so as to maintain the normal performance of the machine and reduce the possibility of causing greater failures. In a sense, timely handling of failures is an effective measure to reduce and prevent failures. The so-called timely treatment is to carry out regular maintenance and repair of the machinery in accordance with the maintenance procedures, and the maintenance and repair of various groups must be carried out as required. The existing maintenance and repair specifications are a summary of years of practical experience, is its scientific and rational, in the absence of major technological progress and innovation, these regulations for the repair and maintenance of construction machinery guidance is absolute, must be followed. The second is to strengthen the regular and irregular inspection of construction machinery in the process of use, timely understanding of the operation of the machinery, temporary failures, to deal with in time, do not delay maintenance due to small failures, do not affect the use of time, resulting in greater failure.
5, take the correct technical measures and organizational management measures
With the development of material science and design and manufacturing technology, many new technologies, new materials and new structures have been adopted in construction machinery, which requires the technical support and management of machinery to be more scientific and perfect.
For this reason, as the organization and management personnel and operators of construction machinery, we should pay attention to ensure that the machinery is prevented from damage, deformation, corrosion and so on during transportation and storage. The second is to strictly maintain the daily maintenance of the machinery so that the machinery is in a good technical state. The third is to educate the operator to use and operate all kinds of construction machinery correctly to reduce and prevent mechanical failures caused by human error. Fourthly, we should carefully maintain the machinery, carry out regular and irregular maintenance correctly and reasonably, keep the machinery clean and clean, regularly check the technical status of the machinery, timely treatment of anomalies, timely tightening and adjustment of loose and dysfunctional parts, preventive replacement of some wearing parts, etc.