Core Tip: Maintenance is an effective means to restore the technical performance of engineering machinery, eliminate faults and eliminate hidden troubles, and prolong the service life of the machine. At present, the domestic automobile maintenance industry has a considerable scale, and the construction machinery maintenance industry started relatively late, and there are still many technical problems in the maintenance.
The existence of these problems has led to poor quality of mechanical maintenance and poor equipment reliability, causing losses to consumers and even major engineering and mechanical accidents. The following is a brief analysis of the common technical problems encountered in the maintenance work of construction machinery, aiming to attract the attention of relevant personnel.
It is impossible to correctly judge the analysis failure, and it is common to blindly dismantle and unload
Some maintenance personnel are unclear about the structure and principle of the construction machinery, do not carefully analyze the cause of the failure, can not accurately determine the fault location, blindly dismantle the machinery with the "probably, almost" idea, the result is not only the original fault is not ruled out, and Due to poor maintenance skills and craftsmanship, new problems have arisen. One Nissan Komatsu bulldozer had a problem of insufficient diesel engine power and mechanical failure. The maintenance personnel disassembled and disassembled the PT fuel injection pump and the injector and found no fault. Replaced one fuel pump test and the fault remained. The final inspection failure was caused by excessive internal impurities and moisture in the diesel used, and this disassembly caused the performance of the PT fuel injection pump to drop significantly, and the diesel engine power was insufficient. Therefore, when the machine fails, it must be tested by the testing equipment. If there is no testing equipment, it can be determined by the traditional fault judgment methods and means such as “question, see, check, testâ€, combined with the structure and working principle of the construction machinery. The most likely area of ​​failure. When judging the failure of the construction machinery, the "exclusion method" and the "comparative method" are generally used. The order is from simple to complex, first and then the internal and first assembly and then the parts are removed. Do not ask for the indiscriminate use. ".
Blindly replacing parts, the phenomenon of "replacement repair" exists to varying degrees
It is relatively difficult to judge and eliminate the failure of construction machinery. Some maintenance personnel have always adopted the method of replacement test. Regardless of the large and small parts, as long as it is considered that it may be the component that caused the failure, the test is replaced one by one, and the result is not eliminated, and the fault is not eliminated. Replace the parts that should not be replaced at will, increasing the cost of consumers. A 74 type II excavator, due to steering difficulties to a factory maintenance, the manufacturer replaced the vane pump (steering pump), relief valve, steering cylinder and other components also did not help, and found that the cause of the failure is the steering tank to the vane pump The internal aging rubber of a hydraulic oil pipe is removed, resulting in insufficient flow and pressure of the hydraulic fluid. There are also some faulty parts that can be repaired to restore their technical performance, such as generators, starters, oil coolers, gear oil pumps, etc., which can be repaired without complicated repair process, but the maintenance personnel require users to replace new parts. The method of “replacement repair†is adopted blindly, causing serious waste. The above-mentioned blind replacement test and the practice of replacing the repairable parts are still present to varying degrees in some repair units. During maintenance, the cause and location of the fault should be carefully analyzed and judged according to the fault phenomenon. The repaired parts should be repaired to restore technical performance and eliminate the blind replacement of parts.
Do not check the quality of new parts, the problem of failure after assembly is more common
Before replacing the parts, some maintenance personnel do not perform technical inspections on the new parts, and directly install them on the construction machinery. This is unscientific. At present, the quality of spare parts sold on the market is uneven, and some counterfeit and shoddy parts are mixed with pearls; some accessories have changed performance due to excessive inventory time. If they are not tested, they often cause failure after assembly. 1 Shanghai 120A bulldozer, diesel engine oil cooler freeze crack, resulting in water in the oil, replace a new oil cooler, start the test machine, the oil still in the oil, and check other parts, did not find the cause of the failure.
After disassembling the side cover of the new oil cooler, it was found that the oil seal ring at the side cover was not compacted, which caused the oil and water to mix, because the quality of the oil cooler was not good. One ZL50 loader, the engine oil pressure is too low, the analysis is that the oil filter is clogged, replaced with a new oil filter, the test machine oil pressure is still low. After inspection or replacement of all parts that may cause low oil pressure, but the oil pressure can not be raised, and finally barely used in the case of failure to find the cause of the failure, low oil pressure, resulting in diesel engine burning shaft, crankshaft The fracture and the connecting rod are bent, and the loss is more than 10,000 yuan. After the inspection, the replacement oil filter element (strainer) has been blocked by excessive rust, because the filter is stored in the stock for a long time and causes internal rust. Therefore, it is necessary to carry out necessary inspection tests before replacing new parts. The inspection includes appearance and performance tests to ensure that the new parts are free from malfunctions and prevent unnecessary troubles caused by them.
Concerned about surprises
Label: Common technical problems in engineering machinery maintenance (on)
Previous: Common technical problems in engineering machinery maintenance (below) Next: Types and identification methods of polyamide
Direction Signs,Photoluminescent Aluminum Sheet,Glow In The Dark Sign,Photoluminescent Film
JINAN REALGLOW CO.,LTD , https://www.realglowsign.com