Fourteen kinds of error analysis of engineering machinery maintenance

For the construction machinery, how to better repair the fault in the engineering machinery is an important point. Maintenance is an effective means to restore the technical performance of the engineering machinery, to eliminate the faults and to eliminate the hidden trouble, and to prolong the service life of the machinery. At present, the domestic automobile maintenance industry has a considerable scale, while the construction machinery maintenance industry started relatively late, and there are still many technical problems in the maintenance. The existence of these problems leads to the poor quality of mechanical maintenance, poor reliability of equipment, the loss of consumers, and even the occurrence of major engineering machinery accidents. In view of the common technical problems encountered in the maintenance work of the construction machinery, the road mechanical network of China is briefly analyzed in order to arouse the attention of the relevant personnel.

1 the fault can not be judged correctly, and the phenomenon of blind dismantling and unloading is common.

Some maintenance personnel due to the unclear on the structure and principle of engineering machinery, without a careful analysis of the fault reason, can not accurately determine the fault position, with "probably, almost" blind thought of mechanical dismounting, not only the results of the original fault has not ruled out, but due to poor maintenance skills and technology, and the emergence of new problems. 1 Nissan Komatsu bulldozers appeared diesel engine power shortage and mechanical failure. The maintenance personnel disassembled and decomposed the PT fuel injection pump and injector, nor did they find the cause of the failure. Replace the 1 fuel injection pump test, and the trouble remained. The final inspection is caused by the internal impurities and moisture content of the diesel oil. The demolition results in a significant decline in the performance of the PT fuel injection pump, and the lack of power in the diesel engine. Therefore, when the mechanical failure, should be tested by testing equipment, such as testing equipment, through the fault diagnosis methods and means, check, test, ask to see "the tradition, combined with the structure and working principle of engineering machinery, to determine the most likely failure of the site. In determining the fault of construction machinery, the commonly used "exclusion" and "comparison method", follow from simple to complex, first appearance after the first assembly and parts, internal order, avoid "without forethought, blind dismounting".

2 the blind replacement of parts and parts, the phenomenon of "replacement repair" exists in varying degrees.

Troubleshooting and mechanical engineering judgment is relatively difficult, some maintenance personnel with a consistent method of test, no matter large small pieces, as long as that may be the cause of the fault components, a replacement test, the result not only failure is not ruled out, and the replacement of parts replaced, an increase in consumer spending. 1 sets of 74 type II excavator, due to difficulties to a factory maintenance, replacement of the vane pump manufacturers (steering pump), relief valve, steering cylinder and other parts are of no avail, found the cause of the malfunction to the internal steering vane pump of a hydraulic oil aging glue off, resulting in fluid pressure caused by oil flow and insufficient pressure. Some parts can be repaired to restore fault through its technical properties, such as generator, starter, oil cooler, oil pump gear failure, do not need complex repair technology can repair, but the maintenance staff but requires the user to replace the new thing, just take the method of "replacement and repair", causing serious waste. The blind replacement test and the replacement of the repairable parts are in varying degrees in some repair units. During maintenance, we should carefully analyze and determine the cause and location of the failure according to the failure phenomenon. We should take repair methods to restore the technical performance of the repaired parts, and put an end to the blind replacement of parts.

3 the quality of the new parts is not checked. The problem of failure after assembly is more common.

Before replacing the accessories, some maintenance personnel do not do technical inspection to the new parts, and then install it directly on the engineering machinery. This method is not scientific. Spare parts currently on the market are not bad quality, some fake fish and some accessories; accessories inventory for too long, the performance changes, without detection, often caused by failure after assembly. 1 Shanghai 120A bulldozers, diesel engine oil cooler oil cracking, causing water to replace a new oil cooler, starting test machine, still water in the oil, and examined the other components, fault reason not found.

After the new oil cooler side cover is opened, it is found that the sealing ring at the side cover is not compacted, resulting in the mixing of oil and water. The reason is that the quality of the oil cooler is not good enough. 1 ZL50 loaders, the diesel engine oil pressure is too low, the analysis is the oil filter blockage, the replacement of a new oil filter, the test machine oil pressure is still low. After the check or replace all may lead to low oil pressure parts, but the oil pressure is still not high, finally did not check the reluctance to use fault reason, oil pressure is low, resulting in diesel engine burning tile axle, connecting rod, crankshaft bending loss, million yuan. After checking, the replacement of the filter element (coarse filter) of the oil filter has been blocked by too much rust. The reason is that the filter is kept rusty within a long time. Therefore, we must carry out necessary inspection before changing the new parts, including the appearance and performance test, ensure the new parts are free from failure, and eliminate the unnecessary trouble.

4 do not pay attention to alternative accessories accessories models, or misuse of the more common phenomenon.