Crane wheel rail gauging is a common problem that can significantly affect the normal operation and service life of cranes. When wheels deviate from their proper running tracks and start to “gnaw” on the rails, it not only causes abnormal wear on the wheels and rails but also poses potential safety hazards. Therefore, it is crucial to understand and implement effective repair methods to address this issue promptly and accurately. The following will elaborate on various repair methods for different causes of crane wheel rail gauging.
II. Adjustment of the Main Trolley Drive Mechanism
Precise Adjustment of the Assembly Tightness of the Drive Mechanisms: For cranes with separately driven systems, when assembling the two sets of drive mechanisms, the tightness should be carefully adjusted. This requires meticulous attention to detail to ensure that both drive mechanisms are assembled evenly and properly. Any imbalance in the tightness can lead to inconsistent forces during operation, which may contribute to wheel rail gauging.
Thorough Inspection and Repair of the Speed Difference between the Two Main Trolley Motors: The rotational speed difference between the two main trolley motors must be carefully examined and repaired if necessary. Even a slight difference in motor speeds can cause the crane to move unevenly, resulting in the wheels not following the tracks precisely and eventually leading to rail gauging.
Appropriate Adjustment of the Tightness of the Two Sets of Brakes: The tightness of the two sets of brakes also needs to be adjusted to an appropriate level. If the brakes are too loose, they may not be able to effectively stop the crane when needed, causing excessive movement and potential misalignment of the wheels. On the other hand, if the brakes are too tight, they can create unnecessary resistance during operation, also affecting the smooth running of the wheels and increasing the likelihood of rail gauging.
Inspection and Simultaneous Renewal of Gear Wear in the Reducer and Coupling: Regular inspection of the gear wear in the reducer and coupling is essential. If significant wear is detected, both sides should be renewed simultaneously when replacing the components. Uneven gear wear can cause vibrations and irregularities in the power transmission, which can translate into abnormal wheel movements and rail gauging.
Proper Installation of Conical Tread Wheels: When installing conical tread wheels, special attention should be paid to ensuring that the larger end of the cone faces inward. This correct installation orientation helps to maintain proper wheel alignment and load distribution, reducing the risk of wheels deviating from the tracks during operation.
Effect of Main Girder Deflection on the Trolley Track Distance: After the main girder of the crane deflects downward, the distance between the two tracks for the trolley will become smaller. This reduction in track distance can have different consequences depending on the type of trolley wheels.
Potential Problems for Trolleys with Different Wheel Rim Configurations: For trolleys with a single outer wheel rim, when the track distance becomes too small, there is a risk of derailment during operation. In contrast, for trolleys with double wheel rims, a rail clamping phenomenon may occur. These situations not only disrupt the normal operation of the trolley but also pose a threat to the safety of the entire crane system.
Repair and Reinforcement Measures: To address these issues, flame straightening should be employed to restore the upward camber of the bridge main girder and reinforce it. This process helps to bring the trolley track distance back within the tolerance range, ensuring the smooth running of the trolley. When using flame straightening to correct the downward deflection of the main girder or replacing the tracks, it is important to lift the middle part of the main girder to prevent any damage to the structure during the repair process.
IV. Repair of Rail Gauging for the Main Trolley Caused by Deformation of the Bridge Mechanism
Complex Causes of Main Trolley Rail Gauging: There are multiple reasons for the main trolley to experience rail gauging due to the deformation of the bridge mechanism. Therefore, when repairing this type of rail gauging, it is necessary to be targeted and identify the specific cause accurately.
Use of Flame Straightening for Structural Deformation: For example, when the vertical diagonal deviation of the bridge exceeds the allowable tolerance, flame straightening should be used to correct the structural deformation. This method can effectively restore the proper shape and alignment of the bridge structure, thereby reducing the likelihood of the main trolley wheels deviating from the tracks.
V. Repair of Rail Gauging for the Main Trolley Caused by Wheel Skewness
Analysis and Selection of the Optimal Wheel to Adjust: In cases where the main trolley experiences rail gauging due to wheel skewness, it is necessary to analyze and determine which wheel adjustment will require the least amount of work while achieving the best results. At the same time, when possible, consideration should be given to adjusting the passive wheels first. This is because adjusting the passive wheels may have a relatively smaller impact on the overall operation of the crane while still effectively addressing the rail gauging issue.
Adjustment of Horizontal Wheel Skewness: When adjusting the horizontal skewness of the wheels, the effect of mutual neutralization and cancellation should be taken into account. Before making any adjustments, first use a jack to lift the end beam (or balance beam) so that the wheels are suspended in the air. Then, loosen the fastening bolts for adjustment. For minor adjustments, simply loosen the fastening bolts and insert shims in the keyway of the angular bearing box. For larger adjustments, it may be necessary to chisel off the locating key plate and insert shims between the key plate and the end beam bent plate to achieve the desired adjustment.
Adjustment of Vertical Wheel Skewness: When adjusting the vertical skewness of the wheels, it is advisable to adjust both wheels to be skewed outward. This adjustment orientation is beneficial as it helps to increase the contact area between the wheels and the rails after the bridge structure bears the load. A larger contact area can improve the stability and smooth running of the wheels on the rails, reducing the occurrence of rail gauging.
VI. Adjustment of the Main Trolley Tracks
Strict Adherence to Technical Requirements: The tracks of the main trolley should be adjusted strictly in accordance with the technical requirements. This includes adjusting the elevation, span, and straightness of the tracks accurately. Any deviation from these technical specifications can cause the wheels to run unevenly and lead to rail gauging.
Regular Inspection and Adjustment: Regular inspection of the fastening condition of the bolts is also necessary. For cranes with heavy-duty working conditions and large lifting capacities, the tracks should be inspected and adjusted once every six months. For other cranes, the inspection and adjustment can be carried out once every six months to one year. By maintaining a regular inspection and adjustment schedule, the occurrence of main trolley rail gauging can be effectively prevented.
In conclusion, crane wheel rail gauging is a complex problem that requires a comprehensive understanding of the various causes and corresponding repair methods. By carefully implementing these repair methods and maintaining regular inspections and adjustments, the normal operation and safety of cranes can be ensured, prolonging their service life and reducing maintenance costs.
