A method for repairing a main shaft of a hydraulic turbine

Abstract

The invention discloses a method for repairing a turbine main shaft, which relates to the technical field of turbines and comprises the following steps: S1, hoisting the main shaft on a main shaft support device after comprehensively cleaning the main shaft; S2, installing a boring die, installing the boring die on the flange surface of the main shaft runner end, and checking the mating surface gap between the boring die and the generator end flange along the outer circle direction of the boring die; S3, using a laser tracker to assist in calibration and alignment of the boring die and the main shaft, and setting a positioning taper pin hole, inserting the taper pin, and fixing the boring die; S4, using a laser tracker to assist in calibration and alignment of a machine tool and a workpiece; S5, rechecking the alignment of the workpiece and the machine tool; S6, machining a coupling hole, so that the machined coupling hole corresponds one-to-one to the boring die hole on the boring die; S7, assembling the repaired main shaft on the runner, which solves the problem in the prior art that the old main shaft is returned to a processing plant with large-scale horizontal carriages and boring machine resources for main shaft repair, which results in high cost and long cycle and cannot meet the current unit transformation needs.

Description

Technical Field

[0001] The present invention relates to the technical field of water turbines or water pump turbines, and in particular to a method for repairing a water turbine main shaft. More specifically, it is a process method for expanding and repairing the coupling hole of the original old water turbine or water pump turbine main shaft when a runner or pump impeller is replaced during capacity expansion and transformation of a water turbine generator set. Background Art

[0002] After long-term operation, hydroelectric generator sets require capacity expansion and retrofitting, which typically involves replacing core components. While the turbine typically requires a new runner or water guide mechanism, the main shaft, a core component with a long service life, generally doesn't require a new one. Instead, the old main shaft coupling hole is re-enlarged and repaired based on the coupling hole dimensions and geometric tolerances (pin or bushing dimensions) of the newly fabricated runner.

[0003] During the equipment repair process, the outer diameter of the spindle wheel end flange and the mating seam are usually severely corroded and can no longer be used as a reference for boring and milling the coupling pin hole or pin sleeve hole. Therefore, the traditional operation method is to perform the repair on a large horizontal lathe to provide a qualified reference for boring and milling the coupling hole. The specific operation method is as follows:

[0004] 1) The old spindle is returned to the processing plant and inspected on a large horizontal lathe. The generator end flange and the sliding rotor are used as the reference for alignment. The main inspection is the spindle runner end flange and the matching seam.

[0005] 2) Install a boring die at the spindle runner end (the same boring die used for machining the new runner flange coupling hole), align it with the outer circle as the reference, requiring the point deviation to be ≤0.02mm and the maximum and minimum deviation in the circumferential direction to be ≤0.05. Use the locking bolts to lock it together. After locking, the clearance between the boring die and the flange surface must be 0. Drill and ream the positioning taper pin holes on the boring die and spindle at the same time, and install the positioning pins.

[0006] 3) After the boring die is installed and positioned, the relevant positioning tolerances should be re-tested and the coupling hole can be processed after passing the inspection.

[0007] This treatment method is currently a very mature technical solution, but the old spindle must be returned to a processing plant with both large horizontal lathes and boring machine resources to complete the spindle repair task. The cost of spindle repair is high and the cycle is long, which cannot meet the current unit transformation needs. Summary of the Invention

[0008] The present invention aims to provide a method for repairing a turbine main shaft. This method uses a laser tracker to assist in calibrating and aligning the boring die and main shaft, and the machine tool and workpiece. The workpiece is the combination of the main shaft and boring die, and the machine tool is a movable and adjustable three-axis boring machine. This method allows the coupling hole of an old main shaft to be repaired in situ at the hydropower station site without the use of a large horizontal carriage or large CNC boring machine. This significantly reduces the cost of repairing turbine main shafts in retrofit units and shortens the renovation cycle.

[0009] The present invention is achieved through the following technical solutions:

[0010] A method for repairing a turbine main shaft comprises the following steps:

[0011] S1. After thoroughly cleaning the spindle, hoist it onto the spindle support device;

[0012] S2. Install the boring die on the flange surface of the spindle runner end. Check the clearance between the boring die and the generator end flange along the outer circle of the boring die to ensure that the local deviation is ≤0.02mm.

[0013] S3. Use a laser tracker to assist in calibration and alignment of the boring die and the main shaft. Use the outer diameter of the main shaft generator end flange and the outer diameter of the sliding rotor as the reference for alignment. After the boring die is positioned, tighten the fixing bolts of the boring die, drill and ream at least two positioning taper pin holes together with the main shaft, install the taper pins, and secure the boring die.

[0014] S4. Using a laser tracker to assist in calibration and alignment of a machine tool and a workpiece, wherein the machine tool is a three-coordinate floor-standing boring machine, and the workpiece refers to the spindle and the boring die after alignment;

[0015] S5. Recheck the alignment of the workpiece and the machine tool;

[0016] S6. Processing the coupling hole so that the processed coupling hole corresponds to the boring die hole on the boring die one by one;

[0017] S7. Assemble the repaired main shaft on the runner.

[0018] Furthermore, the alignment method in step S3 includes the following steps:

[0019] S31. Set up two laser tracker measurement stations on both sides of the spindle. The two stations are located in the middle of the spindle axis and are marked as Station A and Station B respectively.

[0020] S32. Arrange at least five laser tracker transfer station reference points below the main shaft at the generator flange position. The reference points should be distributed at different heights, and the axial length of the reference points should be no less than 80% of the total main shaft length.

[0021] S33. Use a laser tracker to collect data from stations A and B. At station A, measure the outer diameter of the main shaft's generator end flange, the sliding rotor, and the outer diameter of the boring die. The measurement data density requirement is: the spacing between circumferential and radial measurement points is controlled within 50 ± 5 mm.

[0022] S34. After the data collection at station A is completed, the collected measurement data is evaluated for reliability. If the evaluation is qualified, the spatial position coordinates of the transfer station reference point are collected and the next step is entered; if the evaluation is unqualified, data collection is required again;

[0023] S35. Move the laser tracker to Station B, collect the spatial position coordinates of the transfer station reference point, transform the origin of the measurement coordinate system of the laser tracker at Station B to the origin of the coordinate system of the laser tracker at Station A through the transfer station reference point, and control the alignment deviation of the transfer station reference point conversion within 0.01 mm / m. Then, collect data of the outer circle of the generator end flange, the sliding rotor, and the outer circle of the boring die at Station B, and perform a reliability assessment on the collected measurement data.

[0024] S36, merging the data collected by station A and station B;

[0025] S37. Using the combined measurement data, fit the outer circle of the generator end flange, the sliding rotor, and the outer circle of the boring die respectively. The roundness and cylindricity shown by the measurement data are controlled within 0.04 mm.

[0026] S38. Calculate the boring die center deviation (X, Y) based on the axis connecting the sliding rotor center and the generator end flange center, where X is the horizontal deviation and Y is the earth's plumb bob deviation.

[0027] S39. Adjust the boring die according to the measurement results to ensure that X≤0.03mm, Y≤0.03mm, the perpendicularity between the axis connecting the sliding rotor center and the generator end flange center and the boring die plane is ≤0.05mm, and the flatness of the boring die itself is ≤0.03mm, so that the clearance between the boring die and the main shaft meets the S2 requirement.

[0028] Furthermore, in steps S34 and S35, the reliability assessment requirements for the measurement data are as follows: the roundness fitting deviation of the generator end flange outer circle and the boring die outer circle measurement data is controlled within 0.03 mm, and the data points exceeding the deviation are removed as noise points; the sliding rotor measurement data is cylindrically fitted, and the fitting deviation is controlled within 0.03 mm, and the data points exceeding the deviation are removed as noise points.

[0029] Furthermore, in step S4, the three-axis floor-standing boring machine is a movable and adjustable three-axis floor-standing boring machine, and the spindle of the three-axis floor-standing boring machine can be adjusted by a distance of 0 to 5 mm so that the machine spindle and the workpiece are concentric and parallel.

[0030] Furthermore, in step S5, the machine tool alignment method includes the following steps:

[0031] S51. Set a laser tracker measurement station between the main workpiece and the machine tool, which is marked as station C. Station C ensures that the laser measurement position can cover 1 / 2 of the outer circle of the boring die, the plane, 1 / 2 of the outer circle of the machine tool spindle, and the reference plane of the machine tool column;

[0032] S52. Use a laser tracker to measure the outer circle and plane of the boring die flange, the outer circle of the machine tool spindle, and the reference plane of the machine tool column at station C. The measurement data density requirement is: the spacing between circumferential and radial measurement points is controlled within 50±5mm;

[0033] S53. After the data collection at station C is completed, the reliability of the collected measurement data is evaluated. If the evaluation result meets the requirements, the next step is entered; if the evaluation result does not meet the requirements, data collection is repeated and steps S51 to S53 are repeated.

[0034] S54. Calculate the parallelism between the boring die plane and the machine column reference plane based on the aforementioned measurement results, requiring the parallelism to be ≤0.02; calculate the perpendicularity between the axis connecting the boring die center and the machine tool spindle center and the boring die plane, requiring the perpendicularity to be ≤0.02mm; then adjust the machine tool based on the measurement and calculation results to ultimately ensure the parallelism and perpendicularity requirements.

[0035] Furthermore, in step S53, the evaluation requirements are: the roundness fitting deviation of the measurement data of the outer circle of the boring die and the outer circle of the machine tool spindle is controlled within 0.02mm; the flatness fitting deviation of the measurement data of the boring die plane and the machine tool column base plane is controlled within 0.02mm, and the data points exceeding the deviation are eliminated as noise points. The data efficiency is not less than 95%. If the measurement data fitting accuracy cannot meet the requirement within 0.02mm, data collection is performed again.

[0036] Furthermore, in step S5, a dial indicator is used to recheck the alignment of the machine tool and the workpiece, and the horizontal and vertical displacement deviations of the boring die plane are checked with a dial indicator, and the alignment deviation is ≤0.02mm; the axial displacement deviation of the outer circle or inner circle of the boring die is checked with a dial indicator, and at least 8 points are measured evenly and symmetrically on the circumference, and the point alignment deviation is ≤0.02mm.

[0037] Furthermore, in step S6, the method for processing the coupling hole includes the following steps:

[0038] S61. Use a dial indicator to find the center of the boring die hole, and semi-finish the coupling hole on the first flange based on the center of the boring die hole. The single-side allowance should be no less than 0.5mm.

[0039] S62. Use the dial indicator to find the center of the boring die hole again, with the deviation ≤φ0.01mm, and finish the first coupling hole;

[0040] S63. Use an inside micrometer to check the machining dimensions of the coupling hole in two symmetrical directions at the middle of the hole depth.

[0041] S64. Use a dial indicator to check the perpendicularity of the coupling hole and the mating surface along the hole axis. The deviation should be ≤0.02mm. Use a dial indicator to check the concentricity of the flange coupling hole and the corresponding hole of the boring die. The deviation should be ≤φ0.02mm.

[0042] S65: Under no pressure, insert the inspection pin to check and confirm that the coupling hole meets the requirements. If the coupling hole size does not meet the requirements, repeat steps S61 to S62, and then fine-process the first coupling hole for a second time, and assemble a pin or pin sleeve of the corresponding size.

[0043] S66, process and inspect the remaining holes according to steps S61 to S65;

[0044] S67. Finally, mark the coupling holes on the flange according to the boring die hole numbers.

[0045] Furthermore, when using a laser tracker for measurement, the instrument preheating time is no less than 20 minutes. After the preheating is completed, the front and rear sight accuracy is checked and calibrated and compensated. The front and rear sight angle deviation is controlled within 0.5 ten-thousandths of a degree. The laser tracker IFM interferometric ranging function is turned on, and an optical spherical prism with a sphericity of ±0.003mm is used for data collection. During data collection, the measurement accuracy is prevented from being affected by vibration and airflow disturbances at the measurement site.

[0046] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0047] 1. In the present invention, without using a large horizontal carriage and a large CNC boring machine, the old main shaft coupling hole can be repaired in situ at the hydropower station site. The "movable and adjustable three-axis boring machine + laser tracker" can be used to accurately complete the processing of the coupling pin hole or the pin sleeve hole. This method has been applied in engineering projects with excellent results, greatly reducing the cycle and cost of repairing the main shaft of the turbine of the modified unit.

[0048] Second, in this invention, a laser tracker is used to assist in the calibration and alignment of a machine tool and workpiece. The machine tool is a three-axis floor-standing boring machine, and the workpiece refers to the combined spindle and boring die after alignment. The three-axis floor-standing boring machine is movable and adjustable. The spindle can be adjusted by 0 to 5 mm, ensuring concentricity and parallelism between the machine tool spindle and the workpiece. The machine tool itself has the advantages of being lightweight and easy to adjust. Large workpieces are difficult to fine-tune due to their heavy weight and large size. Therefore, in this solution, the workpiece is left stationary while the machine tool is adjusted to ultimately repair the spindle. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1It is a diagram of the device involved in the present invention.

[0050] Figure 2 This is a diagram showing the alignment of the boring die and the spindle assisted by a laser tracker.

[0051] Figure 3 This is a schematic diagram of the laser tracker-assisted machine tool and workpiece alignment solution.

[0052] Figure 4 yes Figure 3 Right view of the workpiece.

[0053] Figure 5 It is a cross-sectional diagram of the runner end flange and the boring die.

[0054] Figure 6 yes Figure 3 Schematic diagram of a boring machine.

[0055] Figure 7 It is a flowchart of coupling hole processing.

[0056] Figure 8 It is a schematic diagram of actual measurement and calculation.

[0057] In the figure: 1. Generator end flange; 2. Main shaft support device; 3. Main shaft; 4. Laser tracker; 5. Sliding rotor; 6. Runner end flange; 7. Boring die; 8. Boring machine spindle; 9. Boring machine column; 10. Coupling hole; 11. Boring die hole; 12. Positioning taper pin hole or engagement screw hole. DETAILED DESCRIPTION

[0058] The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

[0059] Example 1

[0060] This embodiment takes the process of expanding and repairing the coupling hole of the original old turbine main shaft by replacing the runner during capacity expansion and transformation of a hydro-turbine generator set as an example to further illustrate the turbine main shaft repair method of this scheme, which is also applicable to the expansion and repair of the coupling hole of the main shaft of a pump turbine, and belongs to the field of turbine or pump turbine technology.

[0061] A method for repairing the main shaft of a turbine, reference Figure 1-8 , comprising the following steps:

[0062] Step 1: After thoroughly cleaning the spindle, hoist the spindle onto the spindle support device 2.

[0063] Step 2: Install the boring die 7 on the surface of the spindle runner end flange 6. Check the clearance between the boring die 7 and the spindle runner end flange 6 along the outer circle direction of the boring die 7. The clearance should be basically 0, and the local deviation should be ≤0.02mm.

[0064] Step 3: Use the laser tracker 4 to assist in calibration and alignment of the boring die 7 and the main shaft 3. The outer circle and stop of the main shaft wheel end flange 6 are severely corroded and cannot be used as an alignment reference. Therefore, the outer circle of the main shaft generator end flange 1 and the outer circle fitting axis of the sliding rotor 5 are used as references for alignment. After the boring die 7 is positioned, tighten the fixing bolts of the boring die 7, and drill and ream at least two positioning taper pin holes 12 together with the main shaft 3. In this embodiment, four positioning taper pin holes 12 are set, and the taper pins are installed to fix the boring die.

[0065] In this step, the alignment method involves the following steps:

[0066] S31. Set up two laser tracker measurement stations on both sides of the spindle. The two stations are located in the middle of the spindle axis and are marked as Station A and Station B respectively. Figure 1 .

[0067] S32. Below the main shaft, at the generator end flange 1, arrange at least five (generally 5 to 6 reference points) laser tracker transfer station reference points. The reference points are spatially distributed at different heights, and the axial length of the reference points shall not be less than 80% of the total length of the main shaft.

[0068] S33. Use the laser tracker 4 to collect the corresponding data of stations A and B. At station A, measure the outer circle of the generator end flange 1 of the main shaft, the sliding rotor 5, and the outer circle of the boring die 7. The measurement data density requirement is: the spacing between the circumferential and radial measurement points is controlled at 50±5mm.

[0069] When using a laser tracker 4 to collect data, warm it up for at least 20 minutes before measurement. After warming up, perform a foresight and rearview accuracy check and calibration, ensuring that the foresight and rearview angle deviation is within 0.5 ten-thousandths of a degree. The laser tracker's IFM interferometry function is also enabled, and data is collected using an optical spherical prism with a sphericity of ±0.003mm. During data collection, the measurement site should be free from strong vibrations, airflow disturbances, and other environmental factors that affect measurement accuracy. During actual operation, professional laser tracker measurement personnel rely on experience to determine vibration and airflow conditions to collect the required data.

[0070] S34. After the data collection at station A is completed, the reliability of the collected measurement data is evaluated. If the evaluation is qualified, the spatial position coordinates of the transfer station reference point are collected and the next step is entered; if the evaluation is unqualified (i.e., the measurement data fitting accuracy cannot meet the requirement of 0.03mm), data collection needs to be repeated.

[0071] In this step, the reliability assessment requirements for the measurement data are as follows: the roundness fitting deviation of the measurement data of the outer circle of the generator end flange 1 and the outer circle of the boring die 7 is controlled within 0.03mm, and the data points exceeding the deviation are removed as noise points; the measurement data of the sliding rotor 5 is subjected to cylindrical fitting, and the fitting deviation is controlled within 0.03mm. The data points exceeding the deviation are removed as noise points. The removed noise points do not exceed 5%. If the noise points exceed 5%, the data points should be reselected for investigation.

[0072] S35. After the fitting accuracy of the measurement data at station A is confirmed to meet the requirements, the laser tracker 4 is moved to station B, and the spatial position coordinates of the transfer station reference point are collected. The origin of the measurement coordinate system of the laser tracker 4 at station B is transformed to the origin of the coordinate system of the laser tracker at station A through the transfer station reference point. The alignment deviation of the transfer station reference point conversion is controlled within 0.01mm / m. Then, the data of the outer circle of the generator end flange 1, the sliding rotor 5, and the outer circle of the boring die 7 are collected at station B, and the reliability of the collected measurement data is evaluated. The data collection and data reliability evaluation of the outer circle of the generator end flange 1, the sliding rotor 5, and the outer circle of the boring die 7 at station B are the same as those at station A.

[0073] In this step, the reliability assessment requirements for the measurement data are as follows: the roundness fitting deviation of the measurement data of the outer circle of the generator end flange 1 and the outer circle of the boring die 7 is controlled within 0.03mm, and the data points exceeding the deviation are removed as noise points; the measurement data of the sliding rotor 5 is subjected to cylindrical fitting, and the fitting deviation is controlled within 0.03mm. The data points exceeding the deviation are removed as noise points. The removed noise points should not exceed 5%. If the noise points exceed 5%, the data points should be reselected for investigation.

[0074] S36. Merge the data collected by Station A and Station B.

[0075] S37. Using the combined measurement data, fit the outer circle of the generator end flange 1, the sliding rotor 5, and the outer circle of the boring die 7 respectively. The roundness and cylindricity shown by the measurement data are controlled within 0.04 mm.

[0076] S38. Calculate the center deviation (X, Y) of the boring die 7 based on the axis connecting the center of the sliding rotor 5 and the center of the generator end flange 1, where X is the horizontal deviation and Y is the earth's plumb bob deviation.

[0077] S39. Adjust the boring die 7 according to the measurement results, and finally ensure that X≤0.03mm, Y≤0.03mm, the perpendicularity between the axis connecting the center of the sliding rotor 5 and the center of the generator end flange 1 and the plane of the boring die 7 is ≤0.05mm, and the flatness of the boring die 7 itself is ≤0.03mm, so that the gap between the boring die 7 and the main shaft 3 meets the S2 requirement.

[0078] Step 4: Use the laser tracker 4 to assist in calibration and alignment of the machine tool and the workpiece. The machine tool is a three-coordinate floor-standing boring machine, and the workpiece refers to the assembled whole after the spindle and the boring die are aligned. The three-coordinate floor-standing boring machine is a movable and adjustable three-coordinate floor-standing boring machine. The spindle position of the three-coordinate floor-standing boring machine can be adjusted by 0~5mm to make the machine tool spindle and the workpiece concentric and parallel.

[0079] Step 5: Recheck the alignment of the workpiece and the machine tool;

[0080] In this step, the machine tool alignment method includes the following steps:

[0081] S51, set up the laser tracker measurement station between the main workpiece and the machine tool, record it as station C, reference Figure 3 Station C ensures that the laser measurement position can cover the outer 1 / 2 of the boring die 7, the plane, the outer 1 / 2 area of ​​the boring machine spindle 8, and the reference plane of the boring machine column 9.

[0082] S52. Use the laser tracker 4 to measure the outer circle and plane of the boring die 7, the outer circle of the boring machine spindle 8, and the reference plane of the boring machine column 9 at station C. The measurement data density requirement is: the spacing between circumferential and radial measurement points is controlled at 50±5mm.

[0083] When using a laser tracker 4 to collect data, warm it up for at least 20 minutes before measurement. After warming up, perform a forward and backward accuracy check and calibration, ensuring that the deviation between the forward and backward angles is within 0.5 degrees. The laser tracker 4's IFM interferometric ranging function is also enabled, and data is collected using an optical spherical prism with a sphericity of ±0.003mm. During data collection, the measurement site should be free of strong vibrations, airflow disturbances, and other environmental factors that could affect measurement accuracy. During actual operation, professional laser tracker measurement personnel rely on experience to determine vibration and airflow conditions to collect the required data.

[0084] S53. After the data collection at station C is completed, the reliability of the collected measurement data is evaluated. If the evaluation result meets the requirements, the process proceeds to the next step. If the evaluation result does not meet the requirements (i.e., the measurement data fitting accuracy cannot meet 0.02 mm), data collection needs to be repeated, and steps S51 to S52 are repeated.

[0085] In step S53, the evaluation requirements are: the roundness fitting deviation of the measurement data of the outer circle of the boring die 7 and the outer circle of the boring machine spindle 8 is controlled within 0.02mm; the flatness fitting deviation of the measurement data of the boring die 7 plane and the boring machine column 9 reference plane is controlled within 0.02mm, and the data points exceeding the deviation are eliminated as noise points. The data efficiency is not less than 95%. If the measurement data fitting accuracy cannot meet the requirement within 0.02mm, data collection is performed again.

[0086] S54. Calculate the parallelism of the boring die 7 plane and the reference plane of the boring machine column 7 based on the aforementioned measurement results, requiring the parallelism to be ≤0.02; calculate the perpendicularity between the axis connecting the center of the boring die 7 and the center of the boring machine spindle 8 and the boring die 7 plane, requiring the perpendicularity to be ≤0.02mm; then adjust the machine tool based on the measurement and calculation results to ultimately ensure the parallelism and perpendicularity requirements.

[0087] In this step, a dial indicator is used to recheck the alignment of the workpiece and the machine tool. The horizontal and vertical displacement deviations of the boring die plane are checked with a dial indicator, and the alignment deviation is ≤0.02mm. The axial displacement deviation of the outer or inner circle of the boring die 4 is checked with a dial indicator, and at least 8 points are measured evenly and symmetrically on the circumference. The point alignment deviation is ≤0.02mm.

[0088] Step 6: Process the coupling hole 10 so that the processed coupling hole 10 corresponds to the boring die hole 11 on the boring die 7 one by one;

[0089] In this step, the processing method of the coupling hole 10 includes the following steps:

[0090] S61, use the dial indicator to find the center of the boring die hole 11, refer to Figure 6 , semi-finish the coupling hole 10 on the first flange according to the center of the boring die hole 11, and the single-side allowance is not less than 0.5mm;

[0091] S62, use the dial indicator to re-find the center of the boring die hole 11, with a deviation of ≤φ0.01mm, and finish machining the first coupling hole 10;

[0092] S63, using an inside micrometer to check the machining dimensions of the coupling hole 10 in two symmetrical directions at the middle of the hole depth;

[0093] S64. Use a dial indicator to check the verticality of the coupling hole 10 and the mating surface along the hole axis. Figure 6 , deviation ≤ 0.02mm, use a dial indicator to check the concentricity of the flange coupling hole 10 and the corresponding hole of the boring die 7, the deviation ≤ φ0.02mm;

[0094] S65, without applying pressure, insert the test pin for inspection, refer to Figure 6 , determine that the coupling hole 10 meets the requirements. When the size of the coupling hole 10 does not meet the requirements, repeat steps S61 to S62, and then fine-process the first coupling hole 10 for a second time, and assemble a pin or pin sleeve of corresponding size;

[0095] S66, process and inspect the remaining holes according to steps S61 to S65;

[0096] S67. Finally, mark the coupling holes 10 on the flange according to the numbers of the boring die holes 11.

[0097] Step 7: Assemble the repaired main shaft 3 on the rotating wheel.

[0098] This method allows the repair of old main shaft coupling holes on-site at the hydropower station without the use of large horizontal carriages and large CNC boring machines. By using a "movable and adjustable three-axis boring machine + laser tracker", the coupling pin hole or pin sleeve hole can be accurately processed. This method has been applied in engineering projects with excellent results, significantly reducing the cycle and cost of repairing the turbine main shaft of the modified unit.

[0099] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for repairing a turbine main shaft, characterized in that: The steps include: S1. After thoroughly cleaning the spindle, hoist it onto the spindle support device; S2. Install the boring die on the flange surface of the spindle runner end. Check the clearance between the boring die and the generator end flange along the outer circle of the boring die to ensure that the local deviation is ≤0.02mm. S3. Use a laser tracker to assist in calibration and alignment of the boring die and the main shaft. Use the outer diameter of the main shaft generator end flange and the outer diameter of the sliding rotor as the reference for alignment. After the boring die is positioned, tighten the fixing bolts of the boring die, drill and ream at least two positioning taper pin holes together with the main shaft, install the taper pins, and secure the boring die. The alignment method in this step includes the following steps: S31. Set up two laser tracker measuring stations on both sides of the spindle. The two measuring stations are located in the middle of the spindle axis and are marked as Station A and Station B respectively. S32. Arrange at least five laser tracker transfer station reference points below the main shaft at the generator flange position. The reference points should be distributed at different heights, and the axial length of the reference points should be no less than 80% of the total main shaft length. S33. Use a laser tracker to collect data from stations A and B. At station A, measure the outer diameter of the main shaft's generator end flange, the sliding rotor, and the outer diameter of the boring die. The measurement data density requirement is: the spacing between circumferential and radial measurement points is controlled within 50 ± 5 mm. S34. After the data collection at station A is completed, the collected measurement data is evaluated for reliability. If the evaluation is qualified, the spatial position coordinates of the transfer station reference point are collected and the next step is entered; if the evaluation is unqualified, data collection is required again; S35. Move the laser tracker to Station B, collect the spatial position coordinates of the transfer station reference point, transform the origin of the measurement coordinate system of the laser tracker at Station B to the origin of the coordinate system of the laser tracker at Station A through the transfer station reference point, and control the alignment deviation of the transfer station reference point conversion within 0.01 mm / m. Then, collect data of the outer circle of the generator end flange, the sliding rotor, and the outer circle of the boring die at Station B, and perform a reliability assessment on the collected measurement data. S36, merging the data collected by station A and station B; S37. Using the combined measurement data, fit the outer circle of the generator end flange, the sliding rotor, and the outer circle of the boring die respectively. The roundness and cylindricity shown by the measurement data are controlled within 0.04 mm. S38. Calculate the boring die center deviation (X, Y) based on the axis connecting the sliding rotor center and the generator end flange center, where X is the horizontal deviation and Y is the earth's plumb bob deviation. S39. Adjust the boring die according to the calculation result of step S38, and finally ensure that X≤0.03mm, Y≤0.03mm, the perpendicularity between the axis connecting the sliding rotor center and the generator end flange center and the boring die plane is ≤0.05mm, and the flatness of the boring die itself is ≤0.03mm, so that the clearance between the boring die and the main shaft meets the requirements of S2; S4. Using a laser tracker to assist in calibration and alignment of a machine tool and a workpiece, wherein the machine tool is a three-coordinate floor-standing boring machine, and the workpiece refers to the spindle and the boring die after alignment; S5. Recheck the alignment of the workpiece and the machine tool; S6. Processing the coupling hole so that the processed coupling hole corresponds to the boring die hole on the boring die one by one; S7. Assemble the repaired main shaft on the runner.

2. A method for repairing a turbine main shaft according to claim 1, characterized in that: In steps S34 and S35, the reliability assessment requirements for the measurement data are as follows: the roundness fitting deviation of the generator end flange outer circle and the boring die outer circle measurement data is controlled within 0.03mm, and the data points exceeding the deviation are removed as noise points; the sliding rotor measurement data is cylindrically fitted, and the fitting deviation is controlled within 0.03mm, and the data points exceeding the deviation are removed as noise points.

3. A method for repairing a turbine main shaft according to claim 1, characterized in that: In step S4, the three-axis floor-type boring machine is a movable and adjustable three-axis floor-type boring machine, and the spindle of the three-axis floor-type boring machine can be adjusted by 0-5 mm so that the spindle of the machine tool is concentric and parallel to the workpiece.

4. A method for repairing a turbine main shaft according to claim 1, characterized in that: In step S5, the machine tool alignment method includes the following steps: S51. Set a laser tracker measurement station between the main workpiece and the machine tool, which is marked as station C. Station C ensures that the laser measurement position can cover 1 / 2 of the outer circle of the boring die, the plane, 1 / 2 of the outer circle of the machine tool spindle, and the reference plane of the machine tool column; S52. Use a laser tracker to measure the outer circle and plane of the boring die flange, the outer circle of the machine tool spindle, and the reference plane of the machine tool column at station C. The measurement data density requirement is: the spacing between circumferential and radial measurement points is controlled within 50±5mm; S53. After the data collection at station C is completed, the reliability of the collected measurement data is evaluated. If the evaluation result meets the requirements, the process proceeds to the next step. If the evaluation result does not meet the requirements, the data is collected again and steps S51 to S53 are repeated. S54. Calculate the parallelism between the boring die plane and the machine column reference plane based on the aforementioned measurement results, requiring the parallelism to be ≤0.02; calculate the perpendicularity between the axis connecting the boring die center and the machine tool spindle center and the boring die plane, requiring the perpendicularity to be ≤0.02mm; then adjust the machine tool based on the measurement and calculation results to ultimately ensure the parallelism and perpendicularity requirements.

5. A method for repairing a turbine main shaft according to claim 4, characterized in that: In step S53, the evaluation requirements are: the roundness fitting deviation of the measurement data of the outer circle of the boring die and the outer circle of the machine tool spindle is controlled within 0.02mm; the flatness fitting deviation of the measurement data of the boring die plane and the machine tool column base plane is controlled within 0.02mm, and the data points exceeding the deviation are eliminated as noise points. The data efficiency is not less than 95%. If the measurement data fitting accuracy cannot meet the requirement within 0.02mm, data collection is performed again.

6. A method for repairing a turbine main shaft according to claim 4, characterized in that: In step S5, a dial indicator is used to recheck the alignment of the machine tool and the workpiece. The horizontal and vertical displacement deviations of the boring die plane are checked with a dial indicator, and the alignment deviation is ≤0.02mm. The axial displacement deviation of the outer or inner circle of the boring die is checked with a dial indicator, and at least 8 points are measured on the circumference to ensure uniformity and symmetry, and the point alignment deviation is ≤0.02mm.

7. A method for repairing a turbine main shaft according to claim 1, characterized in that: In step S6, the method for processing the coupling hole includes the following steps: S61. Use a dial indicator to find the center of the boring die hole, and semi-finish the coupling hole on the first flange based on the center of the boring die hole. The single-side allowance should be no less than 0.5mm. S62. Use the dial indicator to find the center of the boring die hole again, with a deviation of ≤φ0.01mm, and finish machining the first coupling hole; S63. Use an inside micrometer to check the machining dimensions of the coupling hole in two symmetrical directions at the middle of the hole depth. S64. Use a dial indicator to check the perpendicularity of the coupling hole and the mating surface along the hole axis. The deviation should be ≤0.02mm. Use a dial indicator to check the concentricity of the flange coupling hole and the corresponding hole of the boring die. The deviation should be ≤φ0.02mm. S65: Under no pressure, insert the inspection pin to check and confirm that the coupling hole meets the requirements. If the coupling hole size does not meet the requirements, repeat steps S61 to S62, and then fine-process the first coupling hole for a second time, and assemble a pin or pin sleeve of the corresponding size. S66, process and inspect the remaining holes according to steps S61 to S65; S67. Finally, mark the coupling holes on the flange according to the boring die hole numbers.

8. A method for repairing a turbine main shaft according to claim 1, characterized in that: When using a laser tracker for measurement, the instrument should be warmed up for no less than 20 minutes. After warming up, the front and rear sight accuracy should be checked and calibrated and compensated. The front and rear sight angle deviation should be controlled within 0.5 degrees. The IFM interferometric ranging function of the laser tracker should be turned on, and an optical ball prism with a sphericity of ±0.003mm should be used for data collection. During data collection, avoid vibration and airflow disturbances at the measurement site that may affect the measurement accuracy.

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