Recommendations for Skewing Issues on an Overhead Crane
In factory workshops, warehousing and logistics, heavy industry production and other scenarios, bridge cranes are the core heavy-duty operating equipment, and their operating stability directly determines production efficiency, operation safety and equipment service life.Bridge crane deviation is a hidden failure that occurs frequently after the long-term operation of most bridge cranes. It is only manifested as a slight operating deviation in the initial stage, which can easily be ignored by the operator, but long-term letting it go can cause rail gnawing, component damage, shutdown failure and even safety accidents.If you want to completely avoid the hidden dangers of such equipment, it is essential to accurately identify, trace the source and scientifically deal with the deviation of bridge cranes.
What Is Overhead Crane Skewing and Why Does It Matter?
The deviation of the bridge crane is that when the equipment cart is running on the track, the bridge frame cannot maintain a standard straight line and runs in parallel, and there is an abnormal working condition of one-sided advance and overall oblique offset.Normally, the walking mechanisms on both sides of the equipment operate synchronously, and the wheels smoothly fit the track tread, but deviation will cause the bridge frame to produce lateral displacement, causing the wheel rims to continue to rub against the side of the track, which is the core cause of rail failure of lifting equipment.This problem is widespread in all kinds of single- and double-girder bridge cranes, and can occur in old and new equipment of different tonnages. It is a high-frequency hidden danger that equipment operation and maintenance focus on investigating.
Most companies ignore minor bridge crane deviation failures, as everyone knows that they will cause multiple irreversible equipment losses and production losses.Deviation will greatly increase the operating resistance of the equipment, causing continuous high-intensity friction and wear between the wheels and the track, and causing the risk of deformation, damage and even derailment of the components.At the same time, the load of the motors on both sides is unbalanced, frequent overload and tripping, and heat generation is damaged.Long-term deviation will also cause the main beam and end beam to bear twisting stress, causing structural deformation and cracking of welds, and sudden downtime caused by failures will directly disrupt the rhythm of production and increase the operation and maintenance of enterprises and production costs.
Common Signs of an Overhead Crane Skewing Problem
The deviation failure of the bridge crane is obviously gradual, and it will go through a complete process from slight offset to severe rail gnawing and structural damage.Mastering the typical signs of faults can achieve early detection and early correction, so as to avoid small faults from evolving into major hidden dangers. The following are the six core symptoms that are most easily identified on the scene.
Abnormal noise during crane travel
Henan Mine Crane manufactured bridge crane runs smoothly, evenly, and without noise.After the deviation problem occurs, the equipment will continue to emit harsh friction, scratching, and impact sounds when running back and forth, especially in the start-stop and uniform speed operation stages.This is a typical signal of forced friction and squeezing between the rim of the wheel and the side of the track. The louder the noise, the greater the deviation and the more serious the rail gnawing problem.
Uneven wheel or rail wear
Regular inspection of the wheels and tracks can intuitively determine the deviation failure.Under normal working conditions, the wheel tread and track contact surface wear evenly.Deviation equipment will have severe wear on the rim of one-sided wheels, partial wear on the tread, wear, depression, and blockage on one side of the track, and the degree of wear on both sides of the track is greatly different.If the wear of the wheels and tracks is found to be uneven, it can basically be determined that there is a deviation problem of the bridge crane.
One side of the crane moving faster than the other
This is the most intuitive running performance of deviation.The operator can clearly observe that the walking mechanisms on the left and right sides of the bridge crane are out of sync when it is running, and the walking speed on one side is fast and the other side lags behind, causing the bridge frame to gradually tilt and cannot travel in a straight line.This phenomenon is particularly prominent in the start-up and braking stages. Long-term operation will form a fixed offset trajectory, and the failure will continue to increase.
Increased motor load or frequent overload trips
The operating resistance caused by deviation will be directly converted into motor load, and the motor current will increase significantly when the equipment is running, and the heat generation of the fuselage will increase.The electronic control system will frequently trigger overload protection tripping, equipment start-stop failure, and midway shutdown.If the circuit and voltage faults are still tripped frequently after troubleshooting, the core cause is probably the load imbalance caused by the deviation of the bridge crane.
Excessive wheel flange contact with the rail
During normal operation, only the tread of the wheel is in contact with the track, and a standard gap is reserved between the rim and the side of the track.After the deviation failure occurs, the rim will continue to cling to the side of the track, with high-intensity contact and friction throughout the process, without normal clearance margin.Long-term operation will cause excessive wear and deformation of the rims, and even the rims will tighten the track, causing the equipment to fail to move normally.
What Causes Overhead Crane Skewing?
The deviation of the bridge crane is not caused by a single fault, but by the superposition of the four dimensions of track, wheel, drive system, and equipment structure.Combined with many years of equipment maintenance experience, more than 95% of deviation failures come from the following four core causes. Precise positioning of the causes is the key to efficient troubleshooting.
Runway rail misalignment
Track installation deviation and late deformation are the primary external causes of bridge crane deviation, and they are also the most common source of failure on site.The settlement of the foundation of the plant, long-term equipment vibration, and irregular installation and construction will all lead to problems such as deviation of the track gauge, inconsistent elevation of the track on both sides, excessive parallelism of the track, misalignment of the track joints, and loosening and tilting of the pressure plate.When the track flatness, parallelism, and gauge do not meet industry standards, and the walking mechanism of the bridge crane cannot maintain synchronous linear operation, there will inevitably be offset deviation and rail gnawing problems, and the greater the track deviation, the more serious the deviation failure.
Crane wheel wear or incorrect alignment
The wheel is the core component of carrying and walking, and its state directly determines the operating accuracy.On the one hand, the long-term heavy-duty operation of the equipment will lead to uneven wear of the wheel tread, excessive deviation of the wheel diameter on both sides, and wear and deformation of the rim, resulting in inconsistent walking line speeds on both sides, causing deviation.On the other hand, if the equipment installation and maintenance are not in place, the wheels will be horizontally skewed, vertically skewed, the wheel span and diagonal size deviation, and the tapered wheel installation direction is wrong, which completely destroys the walking balance and induces continuous deviation failure.
Drive system and motor synchronization issues
The unsynchronization of the drive systems on both sides is the core cause of the electrical and mechanical transmission levels.After long-term operation, the parameters of the walking motors on both sides do not match, the frequency conversion control parameters are unbalanced, and the braking torque of the brakes is inconsistent, which will cause the motor's operating speed and power output to be out of sync.At the same time, transmission failures such as gear wear, uneven clearance, loose transmission chain, and offset coupling of the reducer will further amplify the difference in operating speed on both sides, and the deviation phenomenon of fast on one side and slow on the other will occur. The fault performance is most obvious in the start-stop phase.
Structural deformation or uneven crane geometry
The structural deformation of the main beam and end beam of the bridge crane is the core internal cause of stubborn deviation.Long-term equipment overload operations, frequent start-stop, hoisting shocks, and perennial stress accumulation will cause the main beam to bend and the end beam to be distorted, and the overall geometry of the equipment will be unbalanced and the diagonal deviation will exceed the standard.In addition, loose equipment flange bolts, cracking of welding parts, and uneven structural force will also cause the installation reference of the walking mechanism to be offset. Even if the wheels are replaced and the track is corrected, the deviation problem will still occur repeatedly.
How to Diagnose and Correct Crane Skewing
In view of the deviation failure of the bridge crane, it is necessary to follow the principles of first diagnosis, then correction, and precise implementation to prevent blind maintenance.Combined with the original technical standards, a set of full-process diagnosis and correction plans that can be landed have been compiled, which are suitable for the repair of deviation faults of various bridge cranes.
Inspect wheel condition and alignment
First, conduct a comprehensive inspection of the walking wheels, measure the diameter of the wheels on both sides, the degree of tread wear, and the thickness of the rim, and check whether the wheels have deformation, cracks, bearing damage and other problems.Focus on detecting the horizontal and vertical skew of the wheels, and check whether the wheel span and diagonal dimensions meet the factory standards.For wheels with excessive wear, excessive dimensional deviation, deformation and damage, they need to be replaced in pairs.In view of the wheel offset problem, the standard wheel alignment accuracy is restored by adjusting the bearing box gasket and correcting the installation position.
Check runway rail alignment and gauge
Use professional measuring tools to detect track gauge, parallelism, elevation difference, and joint flatness, and investigate problems such as loose track pressure plate, rail tilt, track deformation, and foundation settlement.Leveling and correcting tracks with elevation deviations and excessive parallelism, tightening loose track bolts and pressure plates, repairing misplaced and deformed track joints, polishing track wear and raised parts, ensuring that the track parameters on both sides are uniform, flat and parallel, and eliminating the deviation caused by track offset from the root cause.
Test both sides of the crane travel system
Under no-load and heavy-load conditions, the operating status of the walking system on both sides of the bridge crane was tested separately, and the operating speed, start-stop synchronization, and operating resistance difference between the two sides were recorded.For different types of deviation such as out-of-sync starting and braking, continuous offset throughout the process, and intermittent rail gnawing, the fault point is accurately determined.By debugging the frequency conversion control system and calibrating the operating parameters, balancing the walking speed on both sides, correcting the transmission error, and solving the problem of out-of-sync walking.
Inspect motors, gearboxes, brakes, and drive controls
Comprehensively disassemble and inspect the walking motors, reducers, brakes, and electronic control systems on both sides.Investigate motor aging, power imbalance, and coil heating faults, detect reducer gear wear, insufficient lubrication, and abnormal clearance, and calibrate the braking torque of the brakes on both sides to ensure that the brakes are synchronized and the tightness is consistent.At the same time, overhaul the control components such as frequency converters, contactors, and limit switches, update aging electrical components, unify the drive control parameters on both sides, and completely solve the problem of out-of-sync power and transmission.
Correct structural or installation-related issues
For equipment with side bending of the main beam, distortion of the end beam, structural deformation, and excessive diagonal deviation of the main beam, professional correction equipment is used for structural repair, the deformation parts of the main beam and the end beam are corrected, and the standard geometric dimensions of the equipment are restored.Fully tighten the connecting bolts of the whole machine, repair cracked welds, and repair the offset installation reference.For old equipment with serious deformation and structural fatigue, structural reinforcement, component replacement, and machine transformation solutions are provided to completely solve the stubborn structural deviation.
How to Prevent Overhead Crane Skewing
Bridge crane deviation failure can be prevented and controlled. Compared with the high maintenance costs after the failure, normalized preventive maintenance can greatly reduce the equipment failure rate, extend the service life of the equipment, and ensure the long-term stable operation of the equipment.Combined with the original maintenance experience, summarize the four core preventive measures.
Perform regular wheel and rail inspections
Establish a periodic inspection system, check the operating status of wheels and tracks every week, and carry out accurate inspections every month.Focus on checking wheel wear, offset, bearing damage, track flatness, firmness, and wear status, and promptly clean up track debris and polish raised wear parts.Regularly maintain the wheels and tracks, and find minor wear and offset problems and fine-tune them in time to avoid the accumulation of small deviations into serious deviation failures.
Monitor drive system performance
Pay close attention to equipment operating noise, motor temperature, start-stop status, and current load in daily operations, and regularly carry out comprehensive maintenance of motors, reducers, brakes, and electronic control systems.Replace aging lubricants and worn transmission components in time, calibrate braking parameters and electronic control system parameters, ensure that the power output and operating speed of the drive systems on both sides are completely synchronized, and eliminate hidden dangers of deviation from the transmission level.
Maintain runway alignment
Conduct a comprehensive accuracy inspection and calibration of the bridge crane track every quarter, focusing on monitoring the gauge, parallelism, and elevation difference, and promptly correct and repair, tighten and reinforce the track offset and loosening caused by the settlement of the plant foundation and the vibration of the equipment.Long-term maintenance of track installation accuracy in line with industry standards provides a basic guarantee for the linear and stable operation of Henan Mine Crane manufactured bridge cranes.
Address abnormal wear before it develops into a major failure
Adhere to the maintenance principle of early detection and early handling. Once problems such as abnormal noise, slight offset, local wear, and abnormal motor load are found in the operation of the equipment, they will be stopped immediately for investigation and precise repair of hidden dangers.Eliminate faulty operation and delay in maintenance, avoid minor wear and tear, small offsets and gradually evolve into major failures such as gnawing rails, structural deformation, and motor damage, and significantly reduce equipment operation and maintenance and downtime costs.
Henan Mine Crane Factory Custom Custom
The vast majority of repeated bridge crane deviation failures are not caused by simple failure to debug, but by the attenuation of the accuracy of old equipment, the rough manufacturing process of the equipment, the non-standard structural parameters, and the poor adaptability of the drive system.Relying solely on maintenance and correction can only temporarily relieve symptoms, and cannot completely solve hidden dangers. Long-term sick operations will not only continue to increase equipment wear and tear, increase operation and maintenance costs, but also bring stable safety risks, affecting the normal and efficient production of the workshop.
Henan Mine Crane Factory focuses on the research and development and manufacturing of high-quality brand-new bridge cranes, relying on precision production technology and mature working condition adaptation system, optimizing and upgrading from the core dimensions of equipment structure, walking accuracy, drive synchronization, etc., to eliminate common faults such as deviation, rail gnawing, and load imbalance from the source.We can customize and adapt brand-new lifting equipment according to the actual working conditions of the enterprise workshop site, load requirements, operating intensity, etc., and replace old and inefficient equipment with original standardized equipment to help enterprises completely get rid of the problem of deviation and achieve long-term safe, stable and efficient heavy-duty operations.
