Troubleshooting of hydraulic pump damage leading to pipeline blockage

Hydraulic pressure mixing machine hydraulic pump distribution plate repair Hebei Highway Engineering Construction Group Co., Ltd. Duan Yuhu I have a BMW (BOMAG) stabilized soil mixer, due to the pressure of the main hydraulic pump is reduced, resulting in failure to work properly, entering the factory for maintenance.

Upon inspection, it was found that the main hydraulic pump oil was mixed with copper powder, and it was judged that the distribution plate was worn, causing the pressure of the main hydraulic pump to decrease, and the main machine could not work normally.

The main hydraulic pump was dismantled and found that the main and passive distribution plates were all worn out and there were obvious scratches. The two discs were ground simultaneously using a surface grinder and ground until there were no scratches. The thickness is reduced by about 1mm. After grinding, it is refined by grinding the alumina diamond powder and the clean mechanical lubricating oil. After grinding, it is cleaned with kerosene and measured with a knife-edge ruler. The center is concave, not convex.

After passing the test, all parts are cleaned and assembled.

At the same time, the hydraulic system is cleaned from the fuel tank and the pipeline to the main hydraulic pump. After the old oil is discharged, it is washed with gasoline. Then, put a small amount of new hydraulic oil for cleaning, clean it, then refill it with new hydraulic oil, and test it, one success! In this way, we have repaired three similar hydraulic pumps, which basically recovered to normal working pressure and met the needs of the work.

This method is an emergency measure in the maintenance of hydraulic pumps, but only two to three times for the same distribution plate, and finally a new disk should be replaced.

Trouble caused by hydraulic pump damage to pipeline blockage Deng Shaoping of Jiangxi Copper Company Dexing Copper Mine Mining Plant A Caterpillar D10 bulldozer has been running nearly 10,000 hours, and its engine coolant has been working for 2 minutes after the engine is running. Suddenly, the coolant temperature rise alarm and the coolant in the water tank are turned on. Based on this, we conducted a comprehensive inspection of the cooling system and found that the cooling fan speed was extremely low. Because the cooling fan is driven by the hydraulic motor, the pressure of the hydraulic system is checked. It is found that the system pressure is only 1.0 MPa, which is far lower than the normal working pressure of 8.6 MPa. This shows that the problem lies in the hydraulic system, and the hydraulic system principle is as follows. Shown.

The principle of this system is very simple. It consists of only one axial piston pump 11, hydraulic oil cooler 1, hydraulic gear motor 6, and hydraulic lines, and its fan speed is completely controlled by the hydraulic piston pump 11. Therefore, when we disassembled the axial piston pump 11 for decomposition, it was found that the axial piston pump broke two plungers, the shoes were severely worn and the copper sleeve was broken. So far, we have replaced an axial piston pump assembly. As a result, the operator opened a working class on the spot. The above problems were gone, but a new problem appeared. The hydraulic oil in the hydraulic tank was significantly reduced. It was necessary to add several hydraulic oils to work in one shift, and no place was found. Oil leakage, after the operator repaired, the repair personnel made a comprehensive inspection of the hydraulic circuit of the whole machine, no problems were found, and the hydraulic oil tank was filled with hydraulic oil again. 1. Oil cooler 2. Crush tube 3. Water tank 4. Fan 5. Oil pipe 6. Hydraulic motor 7. Oil pipe 8. Fuel tank 9. Servo valve 10 return pipe 1 丨. Axial piston pump 12. Tubing 13. Tubing 14. The bypass valve then starts the engine. After a few minutes, it is found that the oil level of the hydraulic tank drops significantly. This is the result of several round trips. The total fueling is about 300L, while the fuel tank There is not much oil left, the transmission system oil engineering machinery, 2000 (2) tank oil will not increase, where does the hydraulic oil flow? After careful analysis, there is only one place that can accommodate so much hydraulic oil. That is the steering clutch case, and the only way for the oil to flow to the steering clutch case is to enter the hydraulic pump drive box through the two hydraulic stern front end oil seals, and then pump the oil to the steering clutch case through the gearbox clear oil pump; Because the hydraulic system and the variable speed hydraulic control system are two separate systems, and the main hydraulic pump is intact before this failure, there is no such phenomenon; the problem may be caused by the newly replaced axial piston pump. Show.

Then, the axial piston pump was removed again, and it was found that the oil seal 6 at the front end of the hydraulic pump was really damaged. How could the new hydraulic pump assembly that was just replaced be washed out? The reason may be that the hydraulic pump returned to the oil chamber. When the pressure is too high, the back pressure is generated, and the oil seal is washed out to generate internal leakage; and the cause of the excessive pressure in the oil return chamber is that the return oil passage is not smooth. Therefore, the cleaning oil return pipe 10 has a diameter of 15 mm. It was found that the high pressure air flow could not be blown, indicating that the oil pipe was blocked. Later, the oil pipe 10 was cut and found to have a copper block stuck in the oil pipe, which blocked the oil pipe. This copper block is the last time the plunger pump slipped and the person returned to the oil chamber. Since the oil circuit is not cleaned when the hydraulic pump is replaced, the above-mentioned malfunction phenomenon is caused, and after replacing one oil pipe, the problem is solved.

It can be inferred from the above fault phenomenon that the damage of the hydraulic pump to the entire hydraulic system is very serious, and the copper and iron scrap generated by it have serious influence on the control valve, the hydraulic pump and the oil circuit, and will produce cattle. . Chain failure. Therefore, in dealing with such problems, not only must the hydraulic oil and hydraulic filter be replaced, but also the pipeline should be thoroughly cleaned to avoid continuous failure.

Shaft 6. Oil seal 7. Plunger 8. Pump body 9. Oil inlet hydraulic torque converter Turbine precision casting technology research Shenyang Institute of Technology Zhao Zhongxing's quality, improve the hydraulic transmission quality of hydraulic torque converter has important significance . The i:1 eyepiece turbine is an important part of the torque converter. The quality of the casting, the surface roughness and the dimensional accuracy have an important influence on the transmission quality of the torque converter. At present, most of the domestic use of resin sand core, metal type casting method, the turbine blade is extracted in the resin sand core. The aluminum alloy turbine runner surface cast by this method has a surface roughness Ra of 6.3/mi, which is difficult to ensure in dimensional accuracy, and is difficult to cast for a turbine that requires rounded corners of the blade. The metal casting type, the gypsum core precision casting method overcomes the deficiencies of the above process.

2 Test conditions and methods 2.1 The gypsum type material and the proportion of the gypsum slurry used in the proportioning test are shown in Table 1.

Table 1 ratio of stone-based slurry (%) a gypsum aluminum-vanadium additive water (accounting for powder weight) gypsum mixture 2.2 alloy smelting alloy material selected ZL104 alloy, 坩埚 resistance furnace melting engineering machinery, 2000