Views: 0 Author: Site Editor Publish Time: 2025-10-31 Origin: Site
 | The 'Difficult and Complex Problems' of Rotary Drilling Rigs |
| In modern infrastructure construction, rotary drilling rigs, as indispensable heavy machinery, play a crucial role and are widely used in pile foundation construction for various engineering projects such as high-rise buildings, bridges, and subways. However, long-term high-intensity operation and complex and changeable construction environments inevitably lead to various faults in rotary drilling rigs, among which abnormal noises, oil leakage, and insufficient power are the most common 'difficult problems'. These faults not only significantly reduce construction efficiency and increase maintenance costs, but in severe cases, may even cause safety accidents, endangering the lives of construction personnel and bringing huge losses to the entire engineering project. Therefore, timely and accurate diagnosis and resolution of these faults are of great significance for ensuring the normal operation of rotary drilling rigs and guaranteeing the smooth progress of construction projects. |
During operation, if a rotary drilling rig emits abnormal sounds, it is like a person emitting a pained groan, signaling that the equipment is conveying a 'discomfort' message. Different types of unusual noises from different parts often indicate different kinds of faults. Accurately locating the source of the abnormal noise is the key first step to solving the problem.
（1） Abnormal noise in the power head area
When the rotary drilling rig is drilling, if the torque of the power head is insufficient, the forward and reverse rotation speeds are not enough, and there is abnormal noise when the power head motor and reducer are running, then it is necessary to be vigilant. From the perspective of the hydraulic system, insufficient pilot pressure or low relief valve setting pressure can lead to insufficient hydraulic oil pressure, which cannot provide sufficient power to the power head, just like the fuel supply of a car engine is insufficient, and running naturally lacks energy. Damage to the power head motor or large hydraulic oil leakage can also cause problems with power transmission, affecting torque output. From the perspective of mechanical structure, damage to the components of the power head reducer, such as gear wear or breakage, or damage to the mechanical device of the power head gearbox, can cause poor power transmission and subsequently lead to abnormal noise.
When troubleshooting, first check whether the main system pressure of the hydraulic system is normal. If the pressure is normal, it can be preliminarily judged that there is no fault in the hydraulic system, and the mechanical part should be inspected with emphasis. If it is found during inspection that there is a small-scale periodic abnormal noise in the gearbox and motor when the power head is running, it is necessary to further disassemble the power head motor and check whether the motor and output shaft are normal; Remove the gearbox again and carefully inspect its internal components to see if there are any gear damage or other issues. For example, in a construction site, a rotary drilling rig experienced a malfunction where the power head torque was insufficient and accompanied by abnormal noise. After testing the hydraulic system pressure to be normal, technicians disassembled the power head reducer and found that one of the gears had severe wear on its tooth surface. After replacing the gear, the drilling rig resumed normal operation.
（2） Engine abnormal noise
The abnormal noise of rotary drilling rig engines is relatively complex and can be classified into three types: sudden abnormal noise, natural gradual abnormal noise, and artificial abnormal noise.
Sudden abnormal noise refers to the sudden occurrence of engine noise that was not originally present. When the noise is located on the cylinder head and both hot and cold engines are present, the cylinder cut-off method should be used to check when the engine is idling. Cut off the high-pressure oil pipe joints of each cylinder one by one. If the abnormal noise disappears after releasing a certain cylinder, it is likely that the fuel injector of that cylinder is stuck. The fuel injector is like the "injector" of the engine. Once stuck, the fuel injection will be abnormal, causing abnormal noise. If the engine produces a heavy impact sound and the power significantly decreases, making it difficult to idle and emitting black smoke from the exhaust pipe, this may be caused by cylinder pulling, piston ring breakage, poor combustion, and other reasons. For example, poor piston cooling and abnormal operation of the oil nozzle can lead to high engine temperature, which can easily cause such faults. In addition, if there is a dry grinding sound on the engine shaft, it is often due to blockage or oil leakage in the engine inlet pipeline, resulting in poor lubrication of the engine. At this time, the engine temperature will be particularly high, and it must be stopped for inspection and treatment in a timely manner. When the turbocharger rotates and produces a collision sound, it is mainly due to excessive axial or radial movement of the turbocharger, which causes the blades to collide with the housing. This collision sound is easy to hear during variable speed, but may not be very obvious during steady speed due to small vibration.
Natural incremental abnormal noise refers to the sound gradually increasing from non-existent to small, and then gradually expanding. The valve sealing strip is not tightly sealed due to erosion and carbon deposition, which can produce a blow by sound located at the cylinder head. This may be because the valve clearance is too small, causing the valve to expand after heating, resulting in poor sealing; It may also be due to engine oil entering the cylinder, poor atomization of the fuel injector, incomplete combustion, resulting in an increase in engine temperature and causing valve carbon buildup or burns. When the main bearing or connecting rod bearing is worn, the crankshaft will make a loud impact sound, which is located at the oil pan and can be heard clearly from a distance of 10 meters away from the engine. If the connecting rod bearing is severely worn, there will also be the sound of the piston hitting the valve at the same time. At this time, the valve vibration is very large, and the wear of the bearing will reduce the oil pressure. When draining the oil, fragments of the bearing alloy can be seen on the oil plug. It is a very dangerous situation for the bearing to be burned. Once the abnormal noise of burning the bearing is found, it must be stopped immediately for inspection and treatment. Excessive wear on the piston pin and pin hole can cause a heavy impact sound when the piston and cylinder liner pull the cylinder. Due to the difficulty in determining the location of the impact, it is usually necessary to disassemble and inspect to determine. The wear of the gear shaft and excessive clearance between the timing gears can cause a sand scattering impact sound in the gear chamber, which becomes more pronounced when the speed changes. The noise at the clutch occurs when the release bearing is damaged, the driven plate steel plate or rivet is loose or damaged, and the higher the speed, the louder the noise. When the clutch is pressed, the noise becomes smaller or even disappears, and the noise is located at the flywheel housing.
Artificial noise is usually caused by improper installation or adjustment. The abnormal noise caused by excessive valve clearance is located on the cylinder head and is generally noticeable during low-speed cooling, but not during high-speed heating; If the valve clearance is too small, there will be air noise, which is more obvious during warm-up. It can be judged by checking the valve clearance. At a specific speed, the engine produces a vibration sound, sometimes even accompanied by the vibration of the entire vehicle. This may be due to a defect in the chassis structure and engine installation, resulting in resonance sound. Detailed inspection is needed to determine the specific cause. The chaotic airflow impact sound in the exhaust pipe is mainly caused by changes in the engine valve timing, which may be due to bent or broken push rods, broken valve springs, or displacement of crankshaft timing gears or pulleys that are not connected and positioned with locating pins or keys, resulting in abnormal valve timing. This can be solved by checking and adjusting the valve timing.
（3） Main pump abnormal noise
Taking the XCMG XR280D rotary drilling rig as an example, when it performs actions such as hoisting, moving forward and backward, and rotating the power head, the main pump produces intermittent explosive noise, which becomes more pronounced with increasing load. This is a typical main pump noise fault. This situation may be due to poor oil absorption, such as when the hydraulic oil temperature is too low, resulting in excessive viscosity of the hydraulic oil, just like how cooking oil becomes thick and has poor fluidity in winter; Failure to inject oil or exhaust after installation of the main pump, air leakage in the suction pipe, and incomplete opening of the shut-off valve can all affect the suction efficiency of the main pump. Wear and tear of internal components of the main pump, such as the distribution plate, cylinder body, plunger, etc., can cause damage to the main pump and prevent it from working properly. Improper connection and coordination, such as loose connecting bolts of the main pump, wear of the main shaft top shaft and transmission spline, damage to the connecting plate, and large engine transmission jumping, can also cause abnormal noise from the main pump. In addition, the hydraulic oil foam content is too large, causing cavitation of the main pump and damaging the internal components; The quality problem of hydraulic oil prevents the formation of an effective oil film on the internal moving surface of the main pump, resulting in dry friction and abnormal noise.
When troubleshooting, first check if the hydraulic oil in the oil tank is sufficient. The oil level should be visible in the middle of the level gauge and higher than the suction port. Next, check if the main pump body is filled with hydraulic oil. Remove the main pump vent and drain the oil from the main pump housing until the oil continuously flows out without any bubbles; For an oil pump without a vent, the drain pipe can be removed and hydraulic oil can be added to the pump housing. Then check the oil suction pipe of the main pump to ensure that the connection is reliable. The low-pressure rubber pipe is free of deformation, damage and leakage. A small amount of foam water can be applied to the connection of the oil suction pipe to check whether bubbles are sucked in. Also, check the shut-off valve between the main pump and the hydraulic oil tank to see if it can be fully opened, securely fixed, and free of oil leakage. Check the return oil filter element and hydraulic oil again, remove the main return oil filter element, and observe whether there are a large number of visible impurities in the valve core. The hydraulic oil should be transparent and clean. Put the hydraulic oil into a transparent bottle and let it sit for 2-3 hours. If there is no obvious layering in the oil, it indicates that the quality of the hydraulic oil is normal. Finally, carry out a coordinated inspection of the installation of the main pump, remove the main pump, and check whether the connecting plate bolts and spline sleeve fastening bolts of the main pump are loose, and whether there is obvious wear on the elastic coupling splines and main pump splines.
Oil leakage is one of the common faults of rotary drilling rigs, which not only causes waste of hydraulic oil and pollutes the construction site, but also may lead to unstable hydraulic system pressure, affecting the normal operation of equipment. Once oil leakage is discovered on the rotary drilling rig, it must be promptly investigated and effective measures taken to resolve it.
（1） Mast oil cylinder leakage
When the rotary drilling rig experiences oil leakage from the mast cylinder and the vertical mast is not vertical, it may be caused by multiple reasons. From a mechanical perspective, the breakage of the piston rod head of the mast oil cylinder or damage to the oil seal of the mast oil cylinder can lead to oil leakage of the mast oil cylinder. From the perspective of hydraulic systems, internal leakage in oil cylinders or balance valves may be the main culprits for non vertical masts. For example, in actual construction, a rotary drilling rig experienced oil leakage from the mast oil cylinder and a situation where the mast was not vertical. After inspection, it was found that the joint head of the mast piston was broken, which may be due to the main winch wire rope touching the outer surface of the piston rod of the mast oil cylinder during operation, causing damage to the surface of the piston rod and the appearance of grooves, thereby causing damage to the oil cylinder seal. At the same time, the damage to the oil cylinder seal and O-ring, as well as the cracking of the gasket, have also exacerbated the oil leakage phenomenon.
When troubleshooting, the first step is to carefully check whether there are cracks in the joint head of the oil cylinder piston. If there are, further disassemble the mast oil cylinder and check whether there are spots and shallow grooves on the surface of the oil cylinder. Next, open the entire cylinder and oil seal, and check the condition of the oil seal, O-ring, and gasket. If it is determined that these components are damaged, the oil seal, sealing ring, and gasket should be replaced in a timely manner, and then the oil cylinder should be reinstalled and tested to ensure that there is no leakage. After that, the drilling rig can resume normal operation.
（2） Potential oil leakage hazards in other parts
In addition to the mast oil cylinder, hydraulic pipelines, joints, and other oil cylinders of the rotary drilling rig may also experience oil leakage. During long-term use, hydraulic pipelines may be damaged due to wear and aging, leading to hydraulic oil leakage. If the joint is not tightened or the seal is damaged, it can also become a hidden danger point for oil leakage. For example, at a construction site, technicians found oil stains around a hydraulic pipeline joint of a rotary drilling rig during daily inspections. After further inspection, it was found that the seal at the joint was aging, causing hydraulic oil leakage.
In order to detect these oil leakage hazards in a timely manner, it is necessary to conduct daily inspections and observe whether there are oil stains on the surface of the equipment, especially in areas that are prone to oil leakage, and pay special attention to them. Regular maintenance is also essential. According to the maintenance manual of the equipment, the hydraulic system should be checked regularly, including checking the oil level and quality of the hydraulic oil, as well as the sealing condition of each component. Once oil leakage is discovered, for oil leakage caused by loose joints, the joints should be tightened in a timely manner; If the seal is damaged, it needs to be replaced.
（1） Insufficient engine power leads to weak power
The engine, as the power core of the rotary drilling rig, once there is insufficient power, it will make the entire equipment appear "powerless". When the engine is difficult to start, or when there is fatigue, decreased digging torque, fluctuating speed accompanied by abnormal noise or black smoke during operation, it is necessary to be alert to the problem of insufficient engine power.
The reasons for insufficient engine power are multifaceted. From the perspective of power supply, insufficient battery power or loose or oxidized pile heads can cause unstable power supply during startup, resulting in weak engine rotation and inability to start smoothly, just like when the battery power of a mobile phone is low, running various programs will become sluggish. Malfunction of the starter motor or damage to the electromagnetic switch can also affect the start of the engine. The starter motor is like the "starter" of the engine, and if it malfunctions, the engine will be difficult to "wake up".
Abnormal fuel supply system is also a common cause. Insufficient fuel is like a person lacking food, and the engine naturally cannot work properly; Blockage in the fuel circuit prevents smooth delivery of fuel to the engine, leading to insufficient combustion; If the fuel filter is too dirty and cannot effectively filter impurities, or if the diesel fuel used does not match the grade, it may affect the quality of the fuel and thus affect the performance of the engine. For example, at a construction site, the engine of a rotary drilling rig experienced insufficient power. After inspection, it was found that the fuel filter was too dirty. After replacing the filter, the engine resumed normal operation.
The intake system is equally important. Severe dirt on the air filter can lead to poor intake and prevent the engine from obtaining sufficient oxygen, just like how people feel uncomfortable with poor breathing. The combustion efficiency of the engine will also decrease, resulting in insufficient power. In addition, abnormalities in the engine timing system or insufficient cylinder pressure, fuel injection system failures such as clogged fuel injectors, insufficient fuel injection pressure, abnormal fuel injection pump operation, poor intake system, damaged turbocharger or air leakage in the intake manifold, clogged exhaust system, severe carbon buildup in the muffler or exhaust pipe, poor engine lubrication or cooling system failure leading to overheating, and abnormal governor operation can all affect the normal operation of the engine, resulting in insufficient power.
When troubleshooting, the first step is to check the battery status, measure the voltage, clean and tighten the pile head. If the battery is low, it needs to be charged or replaced in a timely manner. Next, check the starter motor and listen for its running sound to determine if there is any abnormal noise or weakness. If necessary, disassemble, repair or replace it. Then confirm that the fuel level is sufficient, check for bends or blockages in the fuel lines, replace the diesel filter, and ensure the use of diesel that meets the requirements. Also, check the air filter and clean or replace the filter element as needed. If the above inspection is unsuccessful, it may involve internal mechanical problems of the engine. Professional maintenance personnel should be contacted for cylinder pressure testing and timing system inspection. Inspect the fuel injection system, clean or replace the fuel injectors, and calibrate the fuel injection pump pressure; Check the connecting pipes of the air filter and turbocharger to ensure smooth air intake. If necessary, repair or replace the turbocharger; Check the exhaust system, remove carbon deposits or replace clogged components; Check the oil level, oil quality, coolant level, and coolant circulation to ensure that the engine is operating at normal temperature; For speed controller issues, professional personnel are required to debug or repair them.
（2） Abnormal hydraulic system causing power issues
The hydraulic system is the core of the action execution of the rotary drilling rig. When the hydraulic system malfunctions and causes insufficient pressure, the various actuators of the equipment, such as the boom, arm, rotary, winch, etc., will move slowly and weakly, as if they are restrained by their hands and feet.
The main pump is severely worn and has excessive internal leakage, just like the internal parts of a water pump are damaged and unable to pump water properly, which can lead to insufficient output pressure and flow of hydraulic oil. The set pressure of the main relief valve is too low or the valve core is stuck or damaged, which makes it impossible to adjust the pressure of the hydraulic system normally and also causes the system pressure to fail to meet the working requirements. Wear, internal leakage, or jamming of the multi way directional valve core can affect the flow and distribution of hydraulic oil, resulting in the actuator being unable to obtain sufficient power. Severe hydraulic oil pollution, low oil level, or uncomfortable viscosity can cause a decrease in lubrication and transmission performance of the hydraulic system, just like problems with human blood, which can also affect bodily functions. Hydraulic pipeline rupture and loose joints leading to leakage can cause hydraulic oil loss and pressure reduction.
When troubleshooting, the first step is to check the hydraulic oil level and quality. If necessary, supplement or replace the hydraulic oil that meets the specifications, and clean the oil tank and filter. By observing the color, transparency, and odor of hydraulic oil, one can preliminarily determine whether the oil quality is normal. Normal hydraulic oil should be clear, transparent, and odorless. Then check all pipelines and joints for obvious leakage points, fasten or replace damaged parts, apply foam water on the joints, and observe whether there are bubbles emerging to detect whether there is leakage. Under the guidance of professional personnel, check the pressure setting of the main relief valve, and adjust or replace it if it is abnormal. If the pressure still does not improve after adjusting the overflow valve, it is necessary to further check the output pressure of the main pump to determine if there is a problem with the pump. Professional pressure detection equipment can be used to measure the output pressure of the main pump. Disassemble and inspect the multi way directional valve, clean the valve core, repair or replace worn parts. During disassembly and installation, pay attention to keeping the environment clean and avoiding impurities from entering the hydraulic system.
In actual construction, it is not uncommon for rotary drilling rigs to experience malfunctions such as abnormal noise, oil leakage, and insufficient power. Below, we will use several specific cases to gain a detailed understanding of the resolution process of these faults and demonstrate the practical application of troubleshooting methods.
Case 1: Solution to power head abnormal noise fault
At a certain bridge construction site, a rotary drilling rig made abnormal noise in the power head area during drilling operations, and the torque was significantly insufficient, seriously affecting the construction progress. After the technicians arrived at the site, they first followed the troubleshooting process to inspect the hydraulic system and found that the pilot pressure and relief valve setting pressure were both normal, preliminarily ruling out the hydraulic system malfunction. Next, carefully listening to the sound of the power head running, it was found that there were small-scale periodic abnormal noises in the gearbox and motor. So, the technicians disassembled the power head motor, checked the motor and output shaft, and found no abnormalities; Subsequently, the gearbox was disassembled and its interior was thoroughly inspected, and it was ultimately discovered that one of the gears in the gearbox had severe wear. After replacing the damaged gear, reinstall the reducer and motor, start the rotary drilling rig, the abnormal noise of the power head disappears, the torque returns to normal, and the drilling rig resumes construction smoothly.
Case 2: Oil leakage treatment of mast oil cylinder
In a high-rise construction project, the mast oil cylinder of the rotary drilling rig experienced oil leakage, and the vertical mast was not vertical, which not only affected the stability of the drilling rig but also posed a threat to construction safety. Technicians quickly investigated the fault and found cracks in the joint head of the oil cylinder piston. Further disassembly of the mast oil cylinder revealed obvious spots and shallow grooves on the surface of the cylinder. After opening the entire cylinder and oil seal, confirm that the cylinder oil seal is damaged, the O-ring is damaged, and the gasket is cracked. In response to these issues, technicians promptly replaced the oil seal, sealing ring, and gasket, reinstalled the oil cylinder, and conducted testing. After testing, there was no leakage in the oil cylinder, the vertical mast was restored, and the rotary drilling rig returned to normal working condition, ensuring the safety and progress of construction.
Case 3: Repair of Insufficient Engine Power
At a construction site of a municipal engineering project, the engine of the rotary drilling rig has a problem of insufficient power, making it difficult to start, weak during operation, decreased excavation torque, and accompanied by black smoke. The technicians first checked the battery and found that the power was sufficient, and the pile head was not loose or oxidized; Next, check the starting motor and ensure it is running normally. Subsequently, the fuel supply system was inspected and it was found that the fuel filter was too dirty. After replacing the filter, the problem persisted. Continuing to check the intake system, it was found that the air filter was severely dirty. After replacing the filter element, the engine power increased slightly, but it has not fully returned to normal. After further testing, it was determined that the blockage of the fuel injector caused the poor fuel injection. After cleaning the fuel injector, the engine started smoothly, power returned to normal, and the rotary drilling rig was put back into efficient construction.
Prevention is better than cure. For rotary drilling rigs, daily maintenance is the key to reducing failures, improving equipment reliability, and extending service life. Doing a good job in daily maintenance is like building a sturdy "protective wall" for a rotary drilling rig, which can effectively prevent various failures and ensure that the equipment is always in good operating condition.
Before construction, a comprehensive inspection of the rotary drilling rig should be conducted. Check whether the oil level in each fuel tank is sufficient and whether the oil quality is normal, such as engine oil, gear oil, hydraulic oil, etc. If the oil quality becomes turbid, emulsified, or has impurities, it should be replaced in a timely manner. When the oil level is insufficient, it is necessary to add oil that meets the specifications. Check the oil quantity and quality of each gearbox gear to ensure normal lubrication of the gearbox. Check whether the main and auxiliary steel wire ropes have broken wires, wear or corrosion, whether the connection is safe and reliable, and whether the force of the rope press is sufficient. If there are broken wires in the steel wire rope, it should be determined whether replacement is needed based on the number and location of the broken wires; When the connection part is loose, it should be tightened in a timely manner. Check whether the lifting device rotates flexibly and whether the internal butter is contaminated. If there are any problems, clean or replace the butter in a timely manner. Inspect the steel structure for cracks, rust, delamination, and other damages, and promptly repair any problems found, such as rust removal and anti-corrosion treatment of slightly corroded areas, and welding repair of cracks. It is also necessary to tighten loose rubber hoses and bolts to prevent leakage or loosening during the construction process, which may cause malfunctions.
During construction, before each shift, grease should be added to the bearings of the drill rod hoist and the drill rod follower guide frame to ensure good lubrication of these parts and reduce wear. Regularly check the integrity of the steel wire rope. If severe wear or broken wires are found, they should be replaced in a timely manner. At the same time, check the damage of the oil pipe and sealing ring. If there is any damage, prepare spare parts for timely replacement to avoid hydraulic oil leakage caused by oil pipe rupture or sealing ring failure. Always pay attention to whether the circuit relay is aging, prepare spare parts early, and prevent equipment operation from being affected by circuit faults.
Regular maintenance is also crucial. The normal oil change interval for an engine is usually 250 working hours. If the operating conditions match the recommended oil type, the oil change interval can be extended to 500 hours. The first maintenance time for diesel engines is 100 hours, and maintenance should be carried out every 250 hours thereafter, including changing the oil filter and oil. The gear oil should be replaced every 500 hours, and the gear oil in the large box should be replaced every 1000 hours. Hydraulic oil should be filtered every 500 hours, replaced completely after the first 1500 hours, and replaced every 2500 hours thereafter (including filter replacement). The lubricating oil of the power head should be checked and replaced regularly. The lubricating oil should be replaced after the first 100 hours of operation, and then every 1000 hours of operation or 12 months (whichever comes first). At the same time, the oil level of the power head reducer should be checked regularly and ensured to be between the upper and lower red markings. In addition, it is necessary to regularly clean the sludge and dust on the equipment, keep the equipment clean, add lubricating grease to each moving part according to the lubrication label, do a good job in anti-corrosion of the equipment, and extend the service life of the equipment. When the equipment is parked or sealed for a long time, necessary maintenance work should be carried out, including checking for faults, lubricating equipment, anti-corrosion, etc; During seasonal changes such as summer and winter, maintenance work should be carried out, including changing lubricating oil and antifreeze.
