A method for correcting and preventing mispositioning of bolt holes of a transmission chain flange of a wind turbine generator system

Abstract

The application discloses a kind of wind generating set transmission chain flange bolt hole misplacement correction and prevention method, comprising the following steps: locking wind wheel, flaw detection, check failure condition and misplacement evaluation;Wait for suitable construction environment condition;Remove the largest part bolt of misplacement amount on transmission chain flange, install suitable correction tooling;Another part bolt is removed, the bolt hole is used as fixed position, install new bolt on fixed position, and is tightened to limited torque using torque tool;Loosen remaining bolt;Use correction tooling to correct until check correction is completed;100% pre-tightening force is applied to loosened bolt;Mark the position of installed expansion bolt, remove the bolt and correction tooling around the position, and ream the hole of expansion bolt position;Install expansion bolt, and re-install or replace new bolt for remaining bolt;Remove all remaining old bolts and replace them, and apply 100% pre-tightening force;Ensure good sealing;Finally, all studs and bolt holes do not interfere, and studs can be normally screwed in and out.

Description

Technical Field

[0001] This invention relates to the field of wind turbine generator maintenance technology, and in particular to a method for correcting and preventing misalignment of flange bolt holes in the transmission chain of a wind turbine generator. Background Technology

[0002] Insufficient interfacial friction can occur at the flange connection surface of the transmission chain due to factors such as design, manufacturing, installation, and interface damage. Under long-term operation of the wind turbine generator set, the bolt holes will become circumferentially misaligned, which will continuously cause the connecting studs to break and the bolts to become stuck and unable to be replaced, posing a great risk to the operation of the unit.

[0003] Currently, technicians mainly have two solutions:

[0004] 1. First, inspect all transmission chain flange connection bolts for defects; then, determine whether to enlarge the holes based on the bolt misalignment dimensions; finally, replace any failed or broken bolts.

[0005] 2. Use lifting equipment to suspend the wind turbine, remove and loosen all pre-set bolts, re-align the bolt holes, and replace broken or failed bolts.

[0006] However, Method 1, circumferential misalignment, usually causes all bolts to be subjected to shear forces in the circumferential direction. Replacing broken or failed bolts does not improve the stress situation of other bolts, and is only a temporary solution. Method 2 is not only costly in terms of manpower and resources, but also carries certain safety risks. Therefore, a new correction method is needed. Summary of the Invention

[0007] The purpose of this invention is to provide a method for correcting and preventing misalignment of bolt holes in the transmission chain flange of a wind turbine generator set, which can improve the circumferential misalignment of the bolt holes.

[0008] The technical solution adopted in this invention is as follows:

[0009] A method for correcting and preventing misalignment of flange bolt holes in a wind turbine generator drive chain includes the following steps:

[0010] Step 1: Adjust the impeller to a Y-shape, insert the impeller locking pin, and lock the impeller. Perform flaw detection on the transmission chain flange bolts to check for bolt failure and assess misalignment. Ensure the impeller remains stable during the correction process and does not rotate due to wind force, thus guaranteeing operator safety. Use non-destructive testing techniques to check the bolts for cracks or other damage and assess their failure status. Measure the degree of misalignment of the bolt holes to provide data support for subsequent correction work.

[0011] Step 2: Wait for suitable construction environment conditions. Choose appropriate weather and wind speed conditions for construction to ensure the safety and efficiency of the operation.

[0012] Step 3: Remove the bolts with the largest misalignment on the transmission chain flange, using these bolt holes as the correction points. Install suitable correction fixtures according to the bolt hole misalignment dimensions. Select the bolts with the largest misalignment for removal; their positions will serve as correction reference points. Install suitable correction fixtures based on the bolt hole misalignment dimensions to provide force and direction for correction. For high-risk aerial operations, verify the strength of the minimum preload bolt quantity and calculate the maximum friction torque T1. Calculate the minimum correction torque T2 for the fixtures based on the number of fixtures and expansion pressure. When T2 ≥ T2 / η (η is the transmission efficiency of the mechanism considered in conjunction with actual working conditions), use a hydraulic expansion correction fixture to correct the misaligned flange bolt holes.

[0013] Step 4: Remove some bolts and use the remaining bolt holes as fixing points. Install new bolts at these fixing points and tighten them to the specified torque using a torque wrench. This prevents the unit from falling off and ensures its safety.

[0014] Step 5: Evenly and symmetrically loosen the remaining bolts in the non-correction and fixed positions one by one. After loosening, do not remove the nuts immediately, but manually tighten them using a puller. Loosen the bolts in the non-correction and fixed positions symmetrically one by one to reduce resistance during the correction process. After loosening, do not remove the nuts immediately, but manually tighten them using a puller to maintain a certain preload.

[0015] Step 6: Use a straightening fixture to straighten the bolts until the straightening is complete. Use the straightening fixture to gradually adjust the position of the bolt holes until the straightening is achieved.

[0016] Step 7: Apply 100% preload to the bolts loosened in Step 5. Ensure the bolts are secure in their new positions.

[0017] Step 8: Mark the location for installing the expansion bolts, remove the bolts and straightening fixtures around the marked location, set up and install a boring machine, and enlarge the hole for the expansion bolt location according to actual needs. To perform the enlargement operation, it is necessary to remove the bolts and straightening fixtures around the marked location to make room for the boring machine. Use the boring machine to enlarge the hole for the expansion bolt location to facilitate the installation of the expansion bolts.

[0018] Step 9: Install expansion bolts. Reinstall or replace the bolts removed in Step 8 and those in the correction position with new bolts. Installing expansion bolts in the enlarged hole position provides a stronger fixing effect. During unit operation, the expansion bolts withstand the shear force of bolt hole misalignment, resist the potential slippage risk of the flange face, and improve the safety of unit operation.

[0019] Step 10: Symmetrically remove all remaining old bolts one by one, replacing them one by one, and apply 100% preload. This ensures a reliable connection.

[0020] Step 11: Inspect the sealant at the outer stop of the connection between the drive chain and the impeller to ensure a good seal. Prevent oil or other media leakage.

[0021] Step 12: Finally, all studs and bolt holes will not interfere with each other, and the studs can be screwed in and out normally.

[0022] This method first adjusts and locks the impeller shape to ensure it doesn't rotate during the correction process, providing a stable operating platform. Next, flaw detection and misalignment assessment of the bolts determine the locations of bolt holes requiring correction. The bolt with the largest misalignment is removed, and a correction fixture is installed, using this misaligned bolt hole as a reference point for correction. Then, a new bolt is installed and tightened at the fixed position, providing support for the correction. During correction, bolts in non-correction and fixed positions are loosened symmetrically and the nuts are manually tightened to ensure even force distribution and prevent new misalignments due to uneven force. The bolt hole positions are gradually adjusted until the correction is achieved. After correction, expansion bolts are installed, or new bolts are replaced, and preload is applied to ensure reliable connection. Finally, the sealant is checked and its sealing is ensured to prevent leakage. Under the premise of ensuring the safety of the unit and personnel, the misalignment of the wind turbine generator transmission chain flange can be corrected without the need for conventional large cranes. The transmission chain flange bolt holes can be corrected without disassembling large components such as the wind turbine, generator, and gearbox, saving manpower and resources and reducing correction costs.

[0023] Alternatively, in step 3, the number of correction positions is calculated and determined based on the torque required to correct misaligned bolt holes. The basic principle of correcting misaligned bolt holes is to overcome the misalignment by applying sufficient torque, allowing the bolt to return to its correct position. The torque must be large enough to generate the necessary force to move the bolt hole, but not so large as to damage the bolt or flange. By calculating and determining the number of correction positions, the force applied to the flange can be more precisely controlled, avoiding excessive force that could damage the flange or bolt. It also reduces unnecessary correction steps, improves correction efficiency, and shortens maintenance time. Furthermore, it ensures that the correction force is evenly distributed on the flange, helping to avoid new misalignments or uneven stress distribution caused by localized stress concentration.

[0024] Alternatively, in step 3, some bolts are evenly removed along the circumference and the bolt holes are cleaned. The locations with the largest misalignments are selected, and appropriate straightening fixtures are chosen based on the bolt hole misalignment dimensions. Bolts are then reinstalled in the remaining holes that do not affect the installation of the straightening fixtures, and the nuts are tightened with a puller. Evenly removing the bolts avoids uneven stress distribution during the straightening process, reducing flange deformation or other structural damage caused by stress concentration. Focusing on straightening the bolt holes with the largest misalignments more effectively addresses the main problem and improves straightening efficiency. Reinstalling the remaining bolts and tightening the nuts with a puller maintains the overall structural integrity of the flange and prevents new misalignments from forming during the straightening process.

[0025] Alternatively, a hydraulic expansion tool can be used as the straightening fixture. This provides very precise force control, ensuring even force application and preventing further damage. It can also generate significant force to move the drive chain flange.

[0026] Alternatively, in step 3, when installing the straightening fixture, after pressurizing to the initial tension force, stop the operation to lock the pressure, measure and record the stroke before and after pressurization, and determine whether the tapered sleeve needs to be replaced based on the remaining stroke of the straightening fixture, keeping the straightening fixture in a taut state within the hole. Begin applying pressure to the straightening fixture to reach a preset initial tension force to ensure a tight fit between the straightening fixture and the bolt hole, preparing for subsequent straightening work. After reaching the initial tension force, stop pressurizing and lock the pressure to ensure the straightening fixture does not lose pressure due to hydraulic system leaks or other reasons. Continuous tension prevents the straightened bolt hole from misaligning again during the straightening process.

[0027] Alternatively, in step 4, a safety calculation is performed to determine the number of new bolts to be replaced. This ensures that the structural integrity and functionality of the drive chain flange are maintained during and after the straightening process, preventing structural failure or performance degradation due to insufficient bolt quantity.

[0028] Alternatively, in step 6, a dial indicator is placed on each side of the flange's center to track the relative displacement before and after correction. Simultaneously, pressure is applied to the correction fixture, and the changes are observed using the dial indicators. If neither dial indicator shows a change, but the correction fixture still has travel, the correction is considered complete and no further correction is needed; the pressure of the correction fixture is then locked. The relative displacement of the flange before and after correction is observed using the dial indicators. If the dial indicators show displacement, it indicates that the correction fixture is working and the flange position is changing. If neither dial indicator shows a change, but the correction fixture still has travel, it indicates that the flange displacement has reached its limit, and further correction will not be effective; thus, the correction is complete. Timely determination of whether correction is complete avoids unnecessary waste of time and resources, and prevents damage to the flange or other structural components due to overcorrection.

[0029] Alternatively, in step 6, all straightening fixtures are slowly pressurized simultaneously until the maximum pressure is reached. This ensures uniform stress distribution on the flange and avoids localized deformation or damage caused by single-point pressurization. It also helps to balance the overall structure of the flange and improve straightening efficiency.

[0030] Alternatively, in step 6, for the straightening fixture that has reached its limit of travel, remove it first, observe it, and measure the maximum dimension through which the hole can pass using a gauge. This allows for the evaluation of the straightening fixture's effectiveness and degree of straightening, ensuring the accuracy and effectiveness of the straightening process. If the measurement results show that the straightening effect is unsatisfactory, the straightening fixture can be replaced.

[0031] Alternatively, in step 8, the number of bolts removed around the hole is determined by the working space of the boring machine. This is to prevent interference between the bolt heads or other structural parts and the boring machine, and to avoid accidental damage during processing.

[0032] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0033] The present invention provides a method for correcting and preventing misalignment of flange bolt holes in a wind turbine generator transmission chain. It employs a correction fixture and replaces the transmission chain bolts according to specified steps. The bolt holes are corrected without the use of large lifting equipment, saving manpower and resources and reducing correction costs. Expansion bolts are used to replace some conventional bolts to prevent bolt hole misalignment from recurring during subsequent unit operation, which could lead to bolt breakage or jamming, thus improving the safety of unit operation. Attached Figure Description

[0034] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0035] Figure 1 This is the flowchart of this solution. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings.

[0037] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0038] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0039] A method for correcting and preventing misalignment of flange bolt holes in the transmission chain of a wind turbine generator set, such as... Figure 1As shown, it includes the following steps:

[0040] Construction safety precautions:

[0041] Step 1: First, adjust the wind turbine to a Y shape, insert the wind turbine locking pin, and lock the wind turbine.

[0042] Step 2: Then check the on-site wind speed, select a safe and suitable construction time, and assign a safety officer to be responsible for issuing early warnings of weather changes.

[0043] Bolt hole misalignment correction:

[0044] Step 3: Mark all bolt holes, using 1-56 for the inner ring and 57-112 for the outer ring. Remove at least 20 bolts evenly, with more bolts removed from the outer ring than the inner ring (15 bolts on the outer ring and 5 on the inner ring). Assess the bolt hole misalignment and select a suitable straightening fixture. Specifically, use a gauge to check the maximum diameter that each hole can pass through. Select the 10 locations with the largest misalignment (preferably the outer ring) for installing the straightening fixture, mark them, and record the data of the maximum gauge diameter that can pass through these 10 holes. Specifically, the number of bolts to be removed and installed with the straightening fixture needs to be calculated based on the torque required to straighten the misaligned bolt holes. The straightening fixture consists of an ultra-high pressure hydraulic pump, high-pressure hydraulic pipelines, and an expansion straightening fixture. The hydraulic pump is a special bidirectional and unidirectional oil pressure delivery system with a pressure ≥1000MPa. Reinstall bolts in the other 10 holes that do not affect the installation of the straightening fixture, and tighten the nuts with a pull rod. Install the straightening fixture, apply an initial tension of approximately 100 bar, then stop the operation to lock the pressure. Measure and record the stroke before and after pressurization. Based on the remaining stroke of the straightening fixture (h≥15mm), determine if the cone sleeve needs replacement, ensuring the straightening fixture remains taut within the hole. The straightening fixture can be selected from existing products. The straightening fixture consists of straightening expansion pins, intermediate hydraulic lines, a pressure output pump, and a displacement monitoring dial gauge. Connect the straightening fixture. When installing the straightening expansion pins, insert 6-8 expansion pins into the corresponding bolt holes, initially pressurize to the set pressure value to tighten the expansion pins, install the displacement monitoring pressure gauge to monitor the amount of misalignment correction, and begin pressurizing through the pressure pump to correct the misaligned bolt holes. After correction, tighten the bolts. Restore the unit's torque value as required.

[0045] Step 4: Replace 20 bolts with new ones and pre-tighten them to 220kN.

[0046] Step 5: Loosen the remaining 82 old bolts one by one, as evenly and symmetrically as possible. Do not remove the nuts after loosening them. Use a puller to tighten the nuts manually.

[0047] Step 6: Place a dial indicator on each side of the flange center, and simultaneously pressurize 10 sets of straightening fixtures. Slowly increase the pressure by 300 bar - 400 bar - 500 bar ... 670 bar, and observe the changes in straightening. Observe the changes in the dial indicators on both sides and whether the stroke of the straightening fixture has reached the bottom to determine whether the wind turbine has been straightened. If the two dial indicators do not change but the straightening fixture still has stroke, it can be determined that the straightening is over and no further action is needed. Lock the pressure of the straightening fixture.

[0048] Step 7: After the correction is completed, stretch all bolts (including new bolts) that can be tightened with a tensioner to 100% preload force of 845KN.

[0049] Bolt hole misalignment prevention measures:

[0050] Step 8: Select 6 expansion bolt holes (3 on the inner ring and 3 on the outer ring) as evenly as possible. Remove 10 bolts around the holes according to the boring machine's operating range. Set up the boring machine and fix the fixture to enlarge the holes, changing the bolt holes from their original size to the enlarged size. Salford GripCon expansion bolts are a good option.

[0051] Step 9: Install the expansion bolts and tighten them to 1134 bar. Reinstall the 10 bolts removed in Step 8 or replace them with new bolts. The preload force is 845 kN.

[0052] Step 10: Remove the old bolts one by one symmetrically, replacing them one by one as required. Install the new bolts and stretch them to 845KN.

[0053] Step 11: Check the sealant on the outer stop of the connection between the drive chain and the wind turbine. If necessary, reapply sealant to ensure a good seal.

[0054] Step 12: Finally, all studs and bolt holes will not interfere with each other, and the studs can be screwed in and out normally.

[0055] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A method for correcting and preventing misalignment of flange bolt holes in a wind turbine generator drive chain, characterized in that: Includes the following steps: Step 1: Adjust the wind turbine to a Y-shape, insert the wind turbine locking pin, lock the wind turbine, and perform flaw detection on the transmission chain flange bolts to check for bolt failure and assess misalignment. Step 2: Wait for suitable construction environment conditions; Step 3: Remove the bolts with the largest misalignment on the transmission chain flange, use the bolt hole as the correction point, and install a suitable correction fixture according to the misalignment size of the bolt hole. Step 4: Remove some bolts, use the bolt holes as fixing points, install new bolts at the fixing points, and tighten them to the specified torque using a torque wrench; Step 5: Loosen the remaining bolts in the non-correction and fixed positions one by one in a symmetrical and even manner. Do not remove the nuts after loosening. Use a puller to tighten the nuts manually. Step 6: Use straightening tools to straighten until the calibration is completed; Step 7: Apply 100% preload to the bolts loosened in Step 5; Step 8: Mark the location of the expansion bolts, remove the bolts and straightening fixtures around the location, set up and install the boring machine, and enlarge the hole at the location of the expansion bolts according to actual needs; Step 9: Install expansion bolts, and reinstall or replace the bolts removed in Step 8 and the bolts in the correction position with new bolts. Step 10: Remove all remaining old bolts symmetrically one by one, replacing them one by one, and apply 100% preload. Step 11: Check the sealant on the outer stop of the connection between the drive chain and the wind turbine to ensure a good seal; Step 12: Finally, all studs and bolt holes will not interfere with each other, and the studs can be screwed in and out normally.

2. The method for correcting and preventing misalignment of flange bolt holes in the wind turbine generator transmission chain as described in claim 1, characterized in that: In step 3, the number of correction positions is calculated and determined based on the torque required to correct the misaligned bolt holes.

3. The method for correcting and preventing misalignment of flange bolt holes in the wind turbine generator transmission chain as described in claim 1, characterized in that: In step 3, remove some bolts evenly along the circumference and clean the bolt holes. Select the positions with the largest misalignment and choose a suitable straightening fixture based on the bolt hole misalignment size. Reinstall bolts in other holes that do not affect the installation of the straightening fixture, and tighten the nuts with a puller.

4. The method for correcting and preventing misalignment of flange bolt holes in the wind turbine generator transmission chain as described in claim 1, characterized in that: In step 3, the straightening fixture is a hydraulic expansion tool.

5. The method for correcting and preventing misalignment of flange bolt holes in the wind turbine generator transmission chain as described in claim 4, characterized in that: In step 3, when installing the straightening fixture, after pressurizing to the initial tension force, stop the operation to lock the pressure, measure and record the stroke before and after pressurization, and determine whether the tapered sleeve needs to be replaced based on the remaining stroke of the straightening fixture, keeping the straightening fixture in a taut state inside the hole.

6. The method for correcting and preventing misalignment of flange bolt holes in the wind turbine generator transmission chain as described in claim 1, characterized in that: In step 4, the number of new bolts to be replaced is determined through safety calculations.

7. The method for correcting and preventing misalignment of flange bolt holes in the wind turbine generator transmission chain as described in claim 1, characterized in that: In step 6, a dial indicator is placed on each of the left and right sides of the flange center to track the relative displacement before and after correction. At the same time, the correction fixture is pressurized, and the correction changes are observed through the dial indicators. If the two dial indicators do not change but the correction fixture still has stroke, it can be determined that the correction is over and no further correction is needed. The pressure of the correction fixture is then locked.

8. The method for correcting and preventing misalignment of flange bolt holes in the wind turbine generator transmission chain as described in claim 7, characterized in that: In step 6, all straightening fixtures are slowly pressurized simultaneously until the maximum pressure is reached.

9. The method for correcting and preventing misalignment of flange bolt holes in the wind turbine generator transmission chain as described in claim 8, characterized in that: In step 6, for the straightening fixture that has reached the bottom of its stroke, first remove it, observe it, and use a gauge to measure the maximum size through which the hole can pass.

10. The method for correcting and preventing misalignment of flange bolt holes in the transmission chain of a wind turbine generator set as described in claim 1, characterized in that: In step 8, the number of bolts around the hole to be removed is determined by the working space of the boring machine.

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