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2024
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03
Fault Analysis of Hydraulic System of Rock Drilling Jumbo
Rock drilling jumbo, also known as "drilling jumbo", is a kind of rock drilling equipment, mainly used for tunnel construction. Our company introduced the first NH178 rock drilling jumbo in 1993. The jumbo has the characteristics of hydraulic control, gas path control, circuit control, waterway control and complex system, and plays a key role in tunnel operation. In this paper, combined with the work practice, the cause of the failure of the hydraulic system of the NH178 drilling rig is analyzed. The hydraulic system failure of the NH178 trolley can be divided into: early stage failure, usability failure and failure caused by improper selection of oil materials; according to the failure phenomenon, it can be divided into: system out of control, system
rock drilling jumboAlso known as "drilling trolley", is a kind of rock drilling equipment, mainly used for tunnel construction. Our company introduced the first NH178 rock drilling jumbo in 1993. The jumbo has the characteristics of hydraulic control, gas path control, circuit control, waterway control and complex system, and plays a key role in tunnel operation. In this paper, combined with the work practice, the cause of the failure of the hydraulic system of the NH178 drilling rig is analyzed. The hydraulic system failure of NH178 trolley can be divided into: early stage failure, usability failure and failure caused by improper selection of oil materials; according to the failure phenomenon, it can be divided into: system out of control, system oil leakage and hydraulic oil temperature high failure. Find the cause of the failure, all kinds of problems will be solved.
Early stage fault
1.1 new car cannot be positioned
When the new car is just in place, the jack legs at the end of the drill arm are controlled by horizontal and longitudinal linkage at the left end, horizontal and longitudinal linkage at the right end, and the linked leg oil cylinder extends and retracts at the same time. In this way, when positioning, when the longitudinal leg touches the ground, the system pressure oil through the relief valve pressure return oil, positioning operation is forced to stop. Change the linkage mode to: horizontal linkage at the left and right ends and longitudinal linkage at the left and right ends, or change the linkage control to separate control, and the rock drilling trolley can realize positioning.
1.2 safety valve sensitivity is not high, causing failure
Positioning system The support leg of the jack at the end of the drill arm can be retracted longitudinally or horizontally. The correct positioning method is: extend horizontally before drilling, and then extend longitudinally. After drilling is completed, first retract longitudinally and then retract laterally. If the operation sequence is wrong, because the safety valve sensitivity of the positioning system is not high, it will make the positioning pressure surge, the use of the initial "positioning pipe burst, oil leakage" and other failures, both waste, and delay the tunnel operation time.
Fault caused by 1.3 misoperation
Although the positioning pump has stopped working, the positioning system is still under pressure. If the control handle is accidentally touched or operated by mistake, it may malfunction or even cause an accident. As long as the hydraulic system is properly improved, the misoperation overload protection can be realized, the oil is drained before the pipe burst, the positioning system is protected, and the reliability of the positioning system during drilling of the trolley can be improved, and the hidden dangers of accidents can be eliminated.
Failure Caused by Imperfect Filter System of 1.4 Pressure Oil Circuit
Because the principle of the pressure oil filter system of the NH178 rock drilling rig is that when the filter is blocked, the pressure oil does not return to the fuel tank, but continues to enter the system. This is easy to cause the system out of control, the use of the early often appear to advance the cylinder out of control is the reason. Improving the pressure oil filter system can reduce the system out of control failure.
serviceability failure
Faults caused by 2.1 waterways
If the water source such as the reservoir is not clean, the water filter screen in the machine will be blocked and damaged. If it is not checked and replaced in time, the blades of the booster water pump will be broken or accelerated wear after the sand and gravel enter. In this way, the working water pressure drops and the water control valve cannot be opened. Unable to open, the gas path control part of the whole vehicle cannot work. If you want to continue working, you must change the gas path and unplug the N8 trachea so that the gas path is not affected.Water pressure controlLow water pressure of the trolley. Since the water control valve does not operate, the drilling cannot be stopped when the water is cut off, and the drill rod will inevitably be stuck, the rotating motor will be blocked, and the oil pressure will rise sharply. At this time, if the anti-jam valve does not operate, the pressure will not be released and the oil will not return. The phenomenon of drill pipe sticking, hydraulic oil pipe rupture, system oil leakage or oil temperature rise will definitely occur. In the waterway, poor circulation of the hydraulic oil radiator can also cause high oil temperature.
Failure caused by damage of 2.2 pressure gauge
The nine-way pressure gauges respectively monitor the anti-jamming pressure, positioning pressure and pushing return pressure of the three arms. The three impact pressure gauges can monitor the impact pressure of the three arms. If these pressure gauges are damaged and are not replaced in time, the following problems will occur:(1) due to the wear of hydraulic components and the leakage of pressure oil, the hydraulic system will lose control and cannot work normally;(2) or blindly increase the pressure for work, there will often be oil pipe burst, oil leakage. It was found on site that the pushing pressure of the three arms was 1.2-1.5 times of the normal pressure. The pushing and returning pressure of the three arms is 2-2.5 times of the normal pressure. The impact pressure of the three arms is also high. The anti-jamming drill failed to coordinate its work, did not return when the drill was initially jammed, and often burst pipes and leaked oil. These are all failures caused by increasing the pressure and barely working after the pressure gauge was damaged. At the same time, this is also one of the reasons for the overconsumption of drill bits and drill pipes.
2.3 return system fault
Return oil filterFiltering impurities and cooling function in the oil return system. The working condition of the oil return filter is transmitted to the alarm circuit of the power distribution cabinet through the sensor. When the oil return warning light is on, it will prompt to replace the oil return filter. If the sensor is damaged and not replaced in time, the working condition of the oil return filter will deteriorate. First of all, the blockage causes the oil return pressure to increase and the heat dissipation is poor. If the oil return filter is not replaced, it will cause the hydraulic components to wear and leak and the hydraulic pipeline to burst.
Fault caused by 2.4 circuit
The rock drilling jumbo adopts high voltage power supply and low voltage control. After the circuit fails, the balance will be lost. The heating of electrical components will indirectly affect the hydraulic oil temperature. If the charger is damaged and not repaired, it will causeControl transformerHeat, and pulse generator damage will cause the lubricating oil does not work, wearrock drill, causing oil leakage and heating up.
Hydraulic System Failure Caused by Improper Selection of Oil
At the same time, the inherent impurities brought into the hydraulic system during assembly, the oxides generated during use, and the dust, water, air and other pollutants invaded by the outside during maintenance and assembly will directly or indirectly cause various failures, as long as the system is strengthened Pollution control and keeping the system clean will reduce and avoid failures.
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