Wind turbine generator shaft neck online bush repair method

Abstract

The present application relates to the technical field of metal repair, and discloses an online sleeve repair method for a generator shaft neck of a wind turbine generator, comprising the following steps: rust removal on the surface of a worn shaft neck to obtain a turned shaft neck of the worn shaft neck, and measuring an actual diameter value of the turned shaft neck; calculating a target sleeve interference amount according to the actual diameter value of the shaft neck, a transmission torque requirement and material attribute parameters; determining a shaft sleeve machining size of the worn shaft neck based on the actual diameter value of the shaft neck and the target sleeve interference amount; preparing a customized shaft sleeve with the shaft sleeve machining size based on the shaft sleeve machining size; expanding the customized shaft sleeve by heating; and performing interference fit between the expanded customized shaft sleeve and the turned shaft neck to generate a repaired assembly of the worn shaft neck; performing shape and position tolerance detection on the repaired assembly to determine whether the repaired assembly meets an operation standard. The present application solves the technical problem that a pre-machining sleeve cannot be reliably assembled due to uncontrollable on-site machining precision of the generator shaft neck.

Description

Technical Field

[0001] This invention relates to the field of metal repair technology, and in particular to a method for online bushing repair of wind turbine generator journals. Background Technology

[0002] Wind turbine generator journals are prone to wear during long-term operation, severely impacting unit safety and power generation efficiency. Currently, traditional online repair methods primarily rely on polymer coating or cold welding. While polymer materials are easy to apply, their bonding strength with the metal substrate is limited, making them susceptible to peeling under continuous vibration and torque loads from the wind turbine, resulting in short repair lifespan and poor reliability. Cold welding, although achieving metallurgical bonding, introduces residual stress due to concentrated heat input during the welding process, easily leading to microcracks or deformation in the journal, and even brittle fracture, seriously threatening the safety of the main shaft structure. Neither of these methods can reliably restore the original high-precision dimensions and load-bearing capacity of the journal while repairing wear, failing to meet the fundamental requirements of long-term, highly reliable operation of wind turbines.

[0003] For more demanding repair scenarios, interference fit bushings are a more ideal approach, but implementing them within the confined and swaying nacelle of a wind turbine presents significant challenges. The on-site environment makes it difficult to control the machining accuracy of worn journals, inevitably resulting in deviations between actual and theoretical dimensions. Existing technologies typically involve pre-machining a single bushing according to drawings or preparing multiple bushings of different sizes for trial fitting. Therefore, there is an urgent need to develop an online repair method that can adapt to the high-altitude swaying environment, dynamically determine the optimal interference fit parameters based on real-time machining results, and complete precise bushing customization and assembly. This would fundamentally solve the problems of low reliability and unstable assembly success rate of existing repair technologies, thereby improving the economy and safety of wind turbine operation and maintenance. Summary of the Invention

[0004] This invention provides a method for online bushing repair of wind turbine generator journals, the main purpose of which is to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides a method for online bushing repair of wind turbine generator journals, comprising: S1. Remove rust from the worn journal of the wind turbine generator to obtain the machined journal of the worn journal, and measure the actual diameter value of the machined journal. S2. Calculate the target bushing interference fit of the worn journal based on the measured diameter value of the journal, the predetermined transmission torque requirement, and the material property parameters of the worn journal. S3. Based on the measured diameter of the journal and the interference fit of the target bushing, determine the bushing machining dimensions of the worn journal, and based on the bushing machining dimensions, prepare a customized bushing with the bushing machining dimensions. S4. The customized bushing is heated and expanded, and the heated and expanded customized bushing is press-fitted with the machined journal to generate the repair assembly of the worn journal; S5. Perform geometric tolerance testing on the repair assembly to confirm whether the repair assembly meets the operating standards.

[0006] Optionally, the step of surface rust removal of the worn journal of the wind turbine generator to obtain a machined journal of the worn journal, and measuring the actual diameter value of the machined journal, includes: The worn journal is polished and cleaned to obtain a clean journal. The clean journal is machined to a fixed dimension to obtain the machined journal of the worn journal. In the axial direction of the machined journal, the journal diameter values ​​at three different positions of the machined journal are measured, and the average value of the journal diameter values ​​is calculated to obtain the actual measured journal diameter value of the machined journal.

[0007] Optionally, calculating the target bushing interference of the worn journal based on the measured diameter of the journal, the predetermined transmission torque requirement, and the material property parameters of the worn journal includes: Calculate the minimum engagement pressure required between the worn journal and the custom bushing based on the predetermined transmission torque requirements; Based on the minimum engagement pressure, the measured diameter of the journal, and the material elastic parameters of the worn journal, calculate the minimum effective interference fit required for the worn journal to mate with the custom bushing. Based on the yield strength of the journal material of the worn journal and the yield strength of the bushing material of the custom bushing, calculate the maximum permissible contact pressure between the worn journal and the custom bushing. Based on the smaller of the maximum permissible engagement pressure, the measured diameter of the journal, and the material elasticity parameters, calculate the maximum permissible effective interference fit between the worn journal and the custom bushing. Within the feasible range formed by the minimum effective interference and the maximum effective interference, the target bushing interference of the worn journal is calculated in combination with a preset assembly safety factor.

[0008] Optionally, the target insert interference includes: The rated output power and rated speed of the wind turbine generator determine the torque transmission requirement. The journal Lamé coefficient of the worn journal is determined based on the journal Poisson's ratio. The bushing Lamé coefficient of the custom bushing is determined based on the bushing Poisson's ratio and the journal ratio of the custom bushing. The target bushing interference is calculated based on the transmission torque requirement, the journal Lamé coefficient, and the bushing Lamé coefficient.

[0009] Optionally, determining the bushing machining dimensions of the worn journal based on the measured diameter value of the journal and the target bushing interference fit, and preparing a customized bushing with the bushing machining dimensions based on the bushing machining dimensions, includes: Based on the measured diameter of the journal, the interference fit of the target bushing, and the deformation coordination relationship between the worn journal and the custom bushing under the fitting pressure, the inner diameter machining dimension of the custom bushing is obtained by inverse solution. Based on the inner diameter machining dimensions and the preset bushing strength safety requirements, calculate the outer diameter machining dimensions of the customized bushing; Based on the inner diameter machining dimensions and the outer diameter machining dimensions, a customized bushing with the specified bushing machining dimensions is prepared.

[0010] Optionally, the deformation coordination relationship includes: Under the specified fitting pressure, the sum of the radial shrinkage of the worn journal and the radial expansion of the custom bushing is equal to the interference fit of the target bushing.

[0011] Optionally, the formula for calculating the machining dimensions of the bushing is: ; in, The outer diameter machining dimension of the bushing is the machining dimension. The inner diameter of the custom bushing is machined to the specified dimensions. For the wall thickness safety factor, The maximum permissible engagement pressure between the worn journal and the custom bushing. The yield strength of the custom bushing.

[0012] Optionally, the step of heating and expanding the custom bushing, and then press-fitting the heated and expanded custom bushing with the machined journal to generate a repair assembly for the worn journal, includes: During the heating process of the custom bushing, the custom bushing is uniformly expanded to a preset assembly gap according to the heating process parameters of the custom bushing, so as to obtain the heated and expanded custom bushing. The customized bushing, after being heated and expanded, is fitted along the axial direction of the machined journal to generate a repair assembly for the worn journal.

[0013] Optionally, the step of performing form and position tolerance testing on the repair assembly to confirm whether the repair assembly meets the operating standards includes: Measure the outer diameter of the repair assembly to verify whether the outer diameter has been restored to the tolerance zone of the original design size; The radial runout of the repair assembly under simulated operating conditions is detected to confirm whether the radial runout is lower than the predetermined standard allowable value.

[0014] Optionally, before performing surface rust removal on the worn journal of the wind turbine generator to obtain a machined journal of the worn journal, and measuring the actual diameter value of the machined journal, the method further includes: The wear journal repair device is anchored to the nacelle base of the wind turbine generator to construct an integrated in-nacelle repair workstation for the wind turbine generator.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention, based on on-site measured journal diameter and dynamic calculation of the target bushing interference using a rigorous mechanical model, ensures that the interference fit meets the full torque transmission requirements while avoiding plastic deformation or damage to the journal or bushing due to excessive interference. This allows the repaired journal assembly to restore a safety margin equal to or even better than the original design. It achieves high efficiency and precision in the repair process. The bushing, customized according to the calculation results, can achieve a perfect one-time fit with the machined journal, greatly shortening downtime for maintenance and reducing power generation loss. It eliminates the need to hoist the generator down the tower, saving the expensive costs and lengthy time associated with spare parts procurement, transportation, and large-scale hoisting in traditional replacement methods, significantly reducing overall operation and maintenance costs.

[0016] This invention transforms uncontrollable field variables into precisely compensable design inputs. Specifically, it obtains reliable measured journal diameter values ​​through precise measurement and averaging; by integrating torque requirements, material strength, and geometric parameters into a complete mechanical model, it determines the feasible range of the target bushing interference fit, abandoning empirical estimation and achieving design optimization of the interference fit; and through reverse engineering based on the deformation compatibility principle, it generates unique bushing machining dimensions that precisely correspond to the measured journal diameter, driving customized production. This not only overcomes the inherent problem of low machining accuracy under high-altitude swaying conditions but also forms a standardized, reusable, high-quality online remanufacturing process, which is of great value for improving the operation and maintenance capabilities and economic benefits of wind farms, especially remote and offshore wind farms. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating an online bushing repair method for wind turbine generator journals according to an embodiment of the present invention.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] This application provides a method for online bushing repair of wind turbine generator journals. The execution entity of this method includes, but is not limited to, at least one of the following electronic devices that can be configured to execute the method provided in this application: a server, a terminal, etc. In other words, the method can be executed by software or hardware installed on a terminal device or a server device, and the software can be a blockchain platform. The server includes, but is not limited to, a single server, a server cluster, a cloud server, or a cloud server cluster. The server can be an independent server or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery networks (CDN), and big data and artificial intelligence platforms.

[0021] Reference Figure 1 The diagram shown is a flowchart illustrating an online bushing repair method for wind turbine generator journals according to an embodiment of the present invention. In this embodiment, the online bushing repair method for wind turbine generator journals includes: S1. Remove rust from the worn journal of the wind turbine generator to obtain the machined journal of the worn journal, and measure the actual diameter value of the machined journal. In this embodiment, the process of surface rust removal from the worn journal of the wind turbine generator to obtain a machined journal, and measuring the actual diameter of the machined journal, includes: The worn journal is polished and cleaned to obtain a clean journal. The clean journal is machined to a fixed dimension to obtain the machined journal of the worn journal. In the axial direction of the machined journal, the journal diameter values ​​at three different positions of the machined journal are measured, and the average value of the journal diameter values ​​is calculated to obtain the actual measured journal diameter value of the machined journal.

[0022] Specifically, worn journals refer to the shaft sections on a wind turbine generator that have reduced diameter, scratches, pits, or uneven wear due to abnormal friction with the bearings during long-term operation.

[0023] Specifically, surface rust removal is a general process description that refers to removing all non-ideal layers from the surface of the worn journal that affect subsequent processing and measurement, mainly including oxide scale, hardened layer, oil, dust and other attached impurities.

[0024] Specifically, a machined journal refers to the new surface obtained after mechanically turning a cleaned journal.

[0025] Specifically, the measured diameter value of the journal refers to the diameter value obtained by quantifying the actual physical dimensions of the journal after turning using a measuring instrument.

[0026] Specifically, cleaning the journal is a direct result of the surface rust removal process. It refers to the journal condition after grinding and cleaning, where the metal substrate is exposed, there are no visible contaminants, and it is ready for turning.

[0027] Specifically, fixed-size turning refers to turning the clean journal according to a preset, uniform cutting depth.

[0028] Specifically, the axial direction refers to the direction along the central axis of the journal after turning. The diameter at different locations in this direction may vary slightly due to machine runout, slight bending of the shaft itself, or release of residual stress.

[0029] Specifically, the three different locations refer to at least three axially spaced measurement points selected within the length of the mating section of the journal after turning. These three points typically cover the beginning, middle, and end of the shaft section.

[0030] Specifically, the journal diameter value refers to the diameter reading at each selected different location, which is directly read by a measuring tool at that cross-section.

[0031] Specifically, the average value calculation refers to adding up the obtained journal diameter values ​​(at least three) and then dividing by the number of measurements to obtain an arithmetic mean.

[0032] Furthermore, firstly, using an angle grinder equipped with a wire wheel or sandpaper disc, the entire surface of the worn journal to be repaired is thoroughly machined. This action requires applying uniform pressure and moving circumferentially and axially to completely remove firmly adhering oxide scale, hardened layers, and existing surface damage until a uniform metallic luster is exposed. After machine grinding, grinding debris and oil stains may remain on the surface.

[0033] Then, use a specialized metal cleaner or a non-woven cloth soaked in acetone to repeatedly and thoroughly wipe and clean the polished area. The purpose of this action is to dissolve and remove all grease, fingerprints, and fine dust, ensuring that the metal surface meets the pre-processing cleanliness standards.

[0034] After completing the above two steps, the worn journal is transformed into a clean journal, and its surface is free of any foreign matter that may affect the life of the turning tool or the measurement accuracy.

[0035] Furthermore, the portable lathe is securely mounted on a rigid base within the generator end cover or nacelle, and the concentricity of its spindle and the generator journal is corrected. A specific single-sided turning depth is set according to the repair process requirements. The lathe is started, allowing the cleaned journal to rotate at a uniform speed. The operator manually or via the feed mechanism controls the cutting tool, performing a smooth and continuous cut along the journal's axial direction. The key to this dimensional adjustment is maintaining a constant depth of cut throughout the entire turning length, ensuring that a uniform layer of material is removed, thereby transforming a worn surface that may have taper or ellipticity into a turned journal with a consistent diameter and good cylindricity.

[0036] Further, after turning, allow the journal to cool to room temperature. The operator then uses a calibrated outside micrometer. First, select a measuring position near the shoulder, gently encircle the journal with the measuring face of the micrometer, and slightly wiggle it around the circumference of the journal to find the maximum reading. Record the journal diameter value at that position as denoted as . Then, move axially to the middle position of the shaft segment, and measure and record the second journal diameter value using the exact same operating method, denoted as . Finally, move to the other end of the shaft segment, measure and record the third journal diameter value, denoted as . During measurement, ensure the micrometer is perpendicular to the journal axis. After obtaining three data points, the operator calculates the average value and takes the result. , and The average value. The final calculated value is the measured diameter of the journal, which is officially recorded as the actual diameter value used for all subsequent engineering calculations. .

[0037] In summary, grinding and cleaning eliminate surface impurities that cause abnormal wear and interference to turning tools, ensuring the quality and safety of turning operations. Dimensional turning transforms an unpredictable wear pattern into a known, regular new cylinder, establishing a precise dimensional reference for repair. This determines the upper limit of subsequent repair accuracy and serves as a bridge connecting the old part and the new sleeve.

[0038] In summary, multi-point measurement and averaging calculation, by selecting three different locations along the axial direction and averaging the results, effectively offset the effects of local shape errors, accidental deviations of measuring tools, and minor environmental variations. The final measured diameter of the journal, as a highly reliable input parameter, directly affects the accuracy of subsequent target bushing interference calculations, thus determining the fit strength and ultimate success or failure of the entire bushing repair. This series of actions collectively ensures the accuracy and reliability of the starting point of the online repair process.

[0039] S2. Calculate the target bushing interference fit of the worn journal based on the measured diameter value of the journal, the predetermined transmission torque requirement, and the material property parameters of the worn journal. In this embodiment, calculating the target bushing interference of the worn journal based on the measured diameter of the journal, the predetermined transmission torque requirement, and the material property parameters of the worn journal includes: Calculate the minimum engagement pressure required between the worn journal and the custom bushing based on the predetermined transmission torque requirements; Based on the minimum engagement pressure, the measured diameter of the journal, and the material elastic parameters of the worn journal, calculate the minimum effective interference fit required for the worn journal to mate with the custom bushing. Based on the yield strength of the journal material of the worn journal and the yield strength of the bushing material of the custom bushing, calculate the maximum permissible contact pressure between the worn journal and the custom bushing. Based on the smaller of the maximum permissible engagement pressure, the measured diameter of the journal, and the material elasticity parameters, calculate the maximum permissible effective interference fit between the worn journal and the custom bushing. Within the feasible range formed by the minimum effective interference and the maximum effective interference, the target bushing interference of the worn journal is calculated in combination with a preset assembly safety factor.

[0040] The target insert interference includes: The rated output power and rated speed of the wind turbine generator determine the torque transmission requirement. The journal Lamé coefficient of the worn journal is determined based on the journal Poisson's ratio. The bushing Lamé coefficient of the custom bushing is determined based on the bushing Poisson's ratio and the journal ratio of the custom bushing. The target bushing interference is calculated based on the transmission torque requirement, the journal Lamé coefficient, and the bushing Lamé coefficient.

[0041] Specifically, the predetermined transmission torque requirement refers to the design torque value that the journal must be able to stably and reliably transmit under its rated operating conditions. It is a core functional indicator that the journal assembly must restore after repair, and it is directly related to the wind turbine's power generation capacity.

[0042] Specifically, the minimum engagement pressure refers to the lowest pressure value per unit area that must be achieved at the mating interface between the worn journal and the custom bushing in order to meet the predetermined torque transmission requirements.

[0043] Specifically, the material elastic parameters refer to the physical constants that describe the mechanical behavior of the worn journal and the customized bushing material during the elastic deformation stage, mainly including the elastic modulus and Poisson's ratio.

[0044] Specifically, the minimum effective interference refers to the minimum dimensional difference that must be achieved between the inner diameter of the bushing and the outer diameter of the journal after machining in order to achieve the minimum engagement pressure mentioned above and thus ensure the torque transmission function.

[0045] Specifically, the yield strength of the journal material and the yield strength of the bushing material refer to the critical stress values ​​at which the matrix material of the worn journal and the material of the custom bushing begin to undergo irreversible plastic deformation during the stress process, respectively. They are the ultimate strength properties of the materials themselves.

[0046] Specifically, the maximum permissible joint pressure refers to the maximum unit area pressure calculated based on the yield strength of the journal material and the yield strength of the bushing material, respectively, which ensures that the component will not undergo plastic deformation or strength failure during an interference fit. The smaller of the two values ​​is taken as the ultimate constraint for the entire mating pair.

[0047] Specifically, the maximum effective interference fit refers to the maximum permissible dimensional difference calculated based on the smaller of the aforementioned maximum permissible bonding pressures, which ensures that neither the journal nor the bushing undergoes plastic deformation or damage. It is the upper limit for ensuring structural safety.

[0048] Specifically, the feasible interval refers to a numerical range defined by the minimum effective overshoot and the maximum effective overshoot.

[0049] Specifically, the assembly safety factor refers to an empirical factor or design margin factor that is greater than 0 and less than 1, used to further select a more reliable and convenient interference value for on-site assembly within the feasible range.

[0050] Specifically, the target bushing interference refers to the final determined interference value that will guide the bushing machining. It is the optimal value selected within a feasible range based on theoretical calculations and engineering experience, combined with an assembly safety factor, and is a key output parameter connecting design and manufacturing.

[0051] Further, the predetermined torque transmission requirement of the generator set is first invoked or input. Based on this torque value, the measured diameter of the journal, and the theoretical coefficient of friction between the journal and the bushing, a conversion is performed using engineering mechanics principles. The conversion yields the average normal pressure required per unit area on the entire cylindrical mating surface of the journal and bushing when resisting torque without relative slippage. After this conversion, the specific value of the minimum engagement pressure is obtained.

[0052] Furthermore, after obtaining the minimum engagement pressure, it is incorporated into the calculation along with the measured journal diameter obtained in the previous steps, and the material elastic parameters shared by the journal and bushing, which are found in the material handbook. This step simulates that when this minimum pressure is applied, the solid journal will undergo a slight radial elastic contraction, while the hollow bushing will undergo a slight radial elastic expansion. In order for this pressure to be generated naturally after assembly, the size of the journal before assembly must be larger than the inner hole of the bushing by a specific amount, which is the sum of the elastic deformations of the two. Through this calculation, the minimum effective interference that must be guaranteed to generate the minimum engagement pressure is finally determined.

[0053] Furthermore, the standard yield strength values ​​of the base material of the worn journal and the material planned for manufacturing the bushing are retrieved separately. Then, based on the mechanical model of a thick-walled cylinder, calculations are performed separately for the journal and bushing. In an interference fit, at what pressure acting on the outer surface of the journal or the inner surface of the bushing will the maximum internal stress approach the material's yield strength, thus posing a risk of plastic deformation? After performing this calculation separately for the journal and bushing, two pressure values ​​are obtained. The smaller one is taken as the maximum permissible bonding pressure for the entire repair assembly to ensure the safety of both components.

[0054] Furthermore, using the maximum permissible fitting pressure determined in the previous step as input, and combining it with the measured diameter of the journal and the material's elastic parameters, calculations are performed again. The sum of the journal's shrinkage and the bushing's expansion when the fitting pressure reaches this maximum safety limit is calculated; this sum is the theoretically maximum permissible effective interference. Exceeding this interference will cause the fitting pressure to exceed the safety limit, potentially leading to permanent deformation or damage to the component.

[0055] Furthermore, within the feasible range defined by the minimum effective interference and the maximum effective interference, and in conjunction with a preset assembly safety factor, the specific process for calculating the target bushing interference of the worn journal is as follows: First, determine a clearly defined feasible range: the lower limit is the minimum effective interference, and the upper limit is the maximum effective interference. Next, based on engineering experience or the specific characteristics of high-altitude operations, select an assembly safety factor. This factor means that instead of excessively pursuing near-theoretical strength limits, a more conservative and reliable value within the range is chosen. The final target bushing interference is typically selected within the range through linear interpolation or directly based on the factor. This final value will serve as the direct input for the next stage of bushing size design.

[0056] Furthermore, the predetermined torque transmission requirement, i.e., the design value of the torque that the generator journal needs to transmit. The rated output power of the wind turbine generator and rated speed The formula is directly determined as follows: ; Where, constant Derived from unit conversion, This refers to the rated output power of the wind turbine generator. For the rated rotational speed, the inherent properties of the material and the key geometric features of the component are converted into coefficients that affect the magnitude of deformation.

[0057] Furthermore, the journal Lamé coefficient The calculation formula is: ; Furthermore, The Poisson's ratio of the material is used; journals and bushings typically take the same value. For solid or considered solid wear journals, the coefficient depends only on the Poisson's ratio of the material. .

[0058] Furthermore, the journal Lamé coefficient The calculation formula is: ; in, The journal Lamé coefficient, The journal ratio reflects the influence of the relative thickness of the bushing wall on its stiffness.

[0059] Specifically, rated output power refers to the electrical power value that the wind turbine generator nameplate indicates can continuously and stably output under standard wind resources and grid conditions.

[0060] Specifically, rated speed: refers to the design rotational speed maintained by the main shaft when the generator reaches the above-mentioned rated output power.

[0061] Furthermore, during the preparation phase of the repair plan, engineers or intelligent operation and maintenance systems first accurately extract the precise values ​​of the rated output power and rated speed of the generator from the wind turbine's technical specifications, equipment nameplate, or monitoring database. This translates the macroscopic energy conversion capability and motion state into the torque transmission requirements acting on the specific mechanical component, the journal. This ensures that the repair design's objectives perfectly match the original power output capability of the wind turbine's design. Specifically, the journal Poisson's ratio is one of the inherent elastic mechanical property parameters of the worn journal material. It quantitatively describes the ratio of contraction or expansion in the direction perpendicular to the material when it is stretched or compressed in one direction.

[0062] Specifically, the journal Lamé coefficient is an intermediate calculation coefficient introduced to facilitate the calculation of the elastic deformation of the journal under radial pressure.

[0063] Furthermore, after obtaining the accurate Poisson's ratio value of the journal material, it is substituted into a defined mathematical relationship. The intrinsic physical properties of the material are quantified into a deformation influence factor for subsequent deformation calculations. This factor characterizes the sensitivity of the radial contraction of a solid journal under pressure to the lateral expansion effect of the material.

[0064] Specifically, the Poisson's ratio of a bushing refers to the Poisson's ratio of the material planned to be used to manufacture a custom bushing, and its physical meaning is the same as that of a journal.

[0065] Specifically, the journal ratio is a key geometric parameter. In this method, it specifically refers to the ratio of the measured diameter of the journal to the designed outer diameter of the bushing. It directly reflects the thickness of the future bushing. The closer the ratio is to 1, the closer the inner diameter and outer diameter of the bushing are, and the thinner the wall thickness.

[0066] Specifically, the bushing Lamé coefficient is an intermediate calculation coefficient used to calculate the elastic deformation of a hollow bushing under radial pressure.

[0067] In summary, a robust deterministic computational chain was constructed. In the complex on-site environment of wind turbines, characterized by high-altitude swaying and temperature variations, it eliminates the uncertainties of human experience, anchoring the repair design to the inherent design parameters of the wind turbine, universally accepted scientific constants of the materials, and precise data from on-site measurements. This ensures that the subsequently custom-machined bushings and the on-site machined journals can achieve a theoretically optimal interference fit, thus laying an indisputable theoretical foundation for achieving high-quality, high-reliability online bushing repair.

[0068] In summary, the minimum engagement pressure and minimum effective interference fit establish the functional baseline for the repair. This ensures that the repaired journal assembly has the absolute capability to transmit the rated torque of the fan, preventing functional failure due to insufficient interference fit. This is the fundamental guarantee of the effectiveness of the repair solution.

[0069] In summary, calculating the maximum permissible bonding pressure and the maximum effective interference fit defines the structural safety limit for the repair. This proactively avoids excessive assembly stress in the journal or bushing due to excessive interference fit, preventing the risks of plastic deformation, microcracks, or even fracture, and ensuring the long-term operational safety and lifespan of the repair.

[0070] In summary, by selecting the target bushing interference within the feasible range and combining it with the assembly safety factor, a decision was made that bridged the theoretical and engineering practical gaps. An optimal balance between reliability and feasibility was found. This value not only meets functional and strength requirements but also considers the operational difficulties and uncertainties of heating and assembly in harsh high-altitude environments, ultimately achieving a crucial leap from possible to reliable online repair.

[0071] S3. Based on the measured diameter of the journal and the interference fit of the target bushing, determine the bushing machining dimensions of the worn journal, and based on the bushing machining dimensions, prepare a customized bushing with the bushing machining dimensions. In this embodiment, determining the bushing machining dimensions of the worn journal based on the measured diameter value of the journal and the target bushing interference fit, and preparing a customized bushing with the bushing machining dimensions based on the bushing machining dimensions, includes: Based on the measured diameter of the journal, the interference fit of the target bushing, and the deformation coordination relationship between the worn journal and the custom bushing under the fitting pressure, the inner diameter machining dimension of the custom bushing is obtained by inverse solution. Based on the inner diameter machining dimensions and the preset bushing strength safety requirements, calculate the outer diameter machining dimensions of the customized bushing; Based on the inner diameter machining dimensions and the outer diameter machining dimensions, a customized bushing with the specified bushing machining dimensions is prepared.

[0072] The deformation coordination relationship includes: Under the specified fitting pressure, the sum of the radial shrinkage of the worn journal and the radial expansion of the custom bushing is equal to the interference fit of the target bushing.

[0073] The formula for calculating the machining dimensions of the bushing is: ; in, The outer diameter machining dimension of the bushing is the machining dimension. The inner diameter of the custom bushing is machined to the specified dimensions. For the wall thickness safety factor, The maximum permissible engagement pressure between the worn journal and the custom bushing. The yield strength of the custom bushing.

[0074] Specifically, bushing machining dimensions refer to the final set of dimensional instructions used to directly guide the machine tool in cutting the bushing blank. It includes at least two key dimensions: internal diameter machining dimensions and external diameter machining dimensions.

[0075] Specifically, the inner diameter machining dimension refers to the actual diameter of the inner hole of the customized bushing after machining but before it is assembled onto the journal.

[0076] Specifically, inverse engineering calculation refers to a method of solving problems in reverse. In this scenario, given the desired final interference fit after assembly and the deformation compatibility relationship required to achieve this state, the initial inner diameter of the bushing required to achieve this state is derived in reverse.

[0077] Specifically, the deformation compatibility relationship describes that in an interference fit, the elastic deformation of the journal and bushing is not independent but coupled and must satisfy a geometric equation. Specifically, under the action of fitting pressure, the sum of the radial shrinkage of the journal and the radial expansion of the bushing must equal the difference in radius between the two before assembly. This is the fundamental equation ensuring the accuracy of the calculation.

[0078] Specifically, the preset bushing strength safety requirement refers to the safety margin standard pre-set in the wall thickness design to ensure that the customized bushing does not fail when subjected to maximum working stress. This is usually reflected in a safety factor greater than 1, or a minimum allowable stress criterion that must be met.

[0079] Specifically, the outer diameter machining dimension refers to the outer diameter of the customized bushing after machining. This dimension is determined not only to meet the overall outline requirements after assembly, but also to ensure that the bushing itself has sufficient wall thickness to meet the preset bushing strength safety requirements, thereby maintaining structural integrity when transmitting torque and bearing assembly stress.

[0080] Furthermore, the minimum effective interference amount and maximum effective overshoot It can be calculated using the following standardized formula: ; Furthermore, among them, Represents the desired amount of interference, the minimum effective amount of interference. Or maximum effective overshoot , This is the measured diameter of the journal. To substitute the computational pressure, calculate hour, for ,calculate hour, for , The elastic modulus of the material is one of the material elastic parameters shared by the worn journal and the custom bushing. The journal Lamé coefficient, This is the Lamé coefficient for the bushing.

[0081] In summary, the reverse engineering of the inner diameter machining dimensions achieves a precise mapping from design objectives to manufacturing parameters. This eliminates the possibility of interference fit failure due to unreasonable machining dimensions of the bushing inner hole.

[0082] In summary, the calculation of the outer diameter machining dimensions, while ensuring the connection function, gives the bushing sufficient structural strength to independently bear the working load, avoids the bushing from cracking or plastic deformation due to insufficient wall thickness during service, and ensures the long-term safety of the repair.

[0083] In summary, the fabrication of custom-made bushings completely solves the most challenging adaptation problem in high-altitude on-site repair of wind turbine units through a strategy of precise calculation and targeted manufacturing. This significantly improves repair efficiency, quality, and economy.

[0084] In summary, the above formula transforms the determination of interference from an experience-dependent, fuzzy process into a deterministic calculation process based on classical mechanics, with clearly defined inputs and outputs, programmability, and reproducibility. This not only represents a significant innovation of the method but also greatly improves the consistency and reliability of the repair scheme, ensuring that each repair achieves the expected strength and safety standards under the harsh conditions of wind farms.

[0085] Specifically, deformation compatibility is a fundamental principle describing the geometric compatibility of deformation between two elastic bodies during interference fit assembly.

[0086] Specifically, the "fitting pressure" refers to the uniform radial pressure generated on the contact surface of the custom bushing when it cools and shrinks, forming a tight fit with the machined journal.

[0087] Specifically, the radial shrinkage of the worn journal refers to the slight, elastic reduction in the outer radius of a solid journal that was originally slightly larger than the original size under this pressure.

[0088] Specifically, the radial expansion of the customized bushing refers to the slight, elastic increase in the inner radius of a hollow bushing with a slightly smaller inner diameter under the same pressure.

[0089] Specifically, the target bushing interference refers to the sum of the radius that the journal shrinks and the radius that the bushing expands after assembly and reaching a balanced state, which is exactly equal to the value that the journal radius is greater than the bushing inner hole radius before assembly.

[0090] In summary, this relationship serves to construct an accurate physical model. Its effect is to link a macroscopic, static dimensional requirement with the microscopic, dynamic elastic deformation behavior of the two components. It is the fundamental basis for all subsequent dimensional inverse kinematics and calculations, ensuring that any calculated dimension can physically achieve the preset interference state.

[0091] ; Specifically, The outer diameter machining dimension for the bushing. Representing the outer cylindrical surface diameter of the finished custom bushing, it is one of the final machining instructions to be sent to the machine tool.

[0092] Specifically, The machining dimensions for the inner diameter of the custom bushing. This value is obtained through the inverse solution of the aforementioned deformation compatibility relationship.

[0093] Specifically, The wall thickness safety factor is a preset constant greater than 1. It is used to provide additional design margins based on theoretical calculations to cover unforeseen factors such as the dispersion of material properties, the simplification assumptions of the calculation model, and fatigue during long-term service. It is a quantitative manifestation of engineering safety thinking.

[0094] Specifically, This is the maximum permissible engagement pressure between the worn journal and the custom bushing. This pressure is not arbitrarily set, but rather derived based on the target bushing interference and considering the most demanding operating conditions; it represents the maximum expected pressure that may occur at the mating interface. It serves as a bridge between interference fit design and structural strength verification.

[0095] Specifically, The yield strength of a custom bushing is an inherent mechanical property limit index of the bushing material, representing the stress threshold at which the material begins to undergo irreversible plastic deformation. Its value can be obtained by consulting national standards or material handbooks using the material grade.

[0096] Furthermore, firstly, all known parameters are gathered. This includes the inner diameter machining dimensions, wall thickness safety factor, maximum permissible bonding pressure obtained from the earlier step S3, and the bushing material yield strength obtained from the material database.

[0097] Furthermore, substitute the above parameter values ​​into the formula. First, calculate the square root term in the denominator. This term is essentially a quantity derived from the fourth strength theory, related to the allowable shape change energy of a material. Then, the fractional term is calculated. This result has the dimension of length and physically represents the additional equivalent wall thickness required to satisfy the strength conditions. Finally, adding twice this equivalent wall thickness to the inner diameter yields the minimum machined outer diameter that satisfies all constraints.

[0098] Finally, for the calculated Conduct a reasonableness check, such as ensuring Furthermore, the obtained wall thickness satisfies the feasibility of machining and the overall space constraints.

[0099] In summary, by seamlessly coupling the safety requirement of preventing plastic failure and the service condition of withstanding interference stress into a single equation, functional design and strength verification are completed simultaneously and achieve compliance in one go. The method of deeply embedding specific strength theories into the dimensional chain calculation of the repair process transforms the determination of the bushing's outer diameter from empirical estimation or simple safety factor amplification to precise calculation based on failure physics. This ensures the reliability of the repaired component under extreme operating conditions and is one of the important theoretical pillars of this invention for achieving high-quality online repair.

[0100] S4. The customized bushing is heated and expanded, and the heated and expanded customized bushing is press-fitted with the machined journal to generate the repair assembly of the worn journal; In this embodiment, the step of heating and expanding the custom bushing, and then pressing the heated and expanded custom bushing against the machined journal to generate a repair assembly for the worn journal, includes: During the heating process of the custom bushing, the custom bushing is uniformly expanded to a preset assembly gap according to the heating process parameters of the custom bushing, so as to obtain the heated and expanded custom bushing. The customized bushing, after being heated and expanded, is fitted along the axial direction of the machined journal to generate a repair assembly for the worn journal.

[0101] Specifically, thermal expansion refers to the physical phenomenon in which the customized bushing is uniformly heated by an external heat source, which intensifies the thermal motion of the material atoms, thereby causing an increase in all dimensions of the bushing, such as its inner diameter, outer diameter, and length.

[0102] Specifically, heating process parameters refer to a series of operational variables set to ensure that the heating process is controllable, effective, and does not damage the material.

[0103] Specifically, the preset assembly gap refers to a positive gap that is artificially set between the inner diameter of the customized bushing and the outer diameter of the machined journal after heating.

[0104] Specifically, a customized bushing after heating and expansion refers to a bushing whose dimensions have temporarily expanded to meet the preset assembly clearance requirements after heating according to the heating process parameters.

[0105] Specifically, axial fitting refers to the linear motion process of aligning the center line of the inner hole of the customized bushing after heating and expansion with the center line of the machined journal, and then translating the bushing along a direction parallel to the center line and fitting it into the designated mating position of the journal.

[0106] Specifically, the repair assembly refers to a rigid, integrated component formed by an interference fit between a custom bushing that has been heated and expanded, fitted onto a machined journal, and cooled to ambient temperature.

[0107] Furthermore, the heating process parameters are first determined based on the material and wall thickness of the customized bushing and the calculated target bushing interference.

[0108] Furthermore, for example, if a mobile induction heater is selected, its heating temperature setpoint needs to be calculated: ; in, This is the heating temperature setpoint. To determine the target interference fit, This represents the desired assembly clearance allowance. is the coefficient of linear expansion of the material. To customize the inner diameter of the bushing, The ambient temperature is set. Simultaneously, a reasonable heating rate and holding time are set to ensure even heat penetration.

[0109] The customized bushing is horizontally suspended or supported, and the induction heating coil is evenly wrapped around the center of the outer circumference of the bushing. The heating equipment is started, and operation is strictly performed according to the set heating process parameters. Throughout the heating process, an infrared thermometer is used to continuously monitor the temperature of the bushing, especially the area around the inner bore, ensuring that it reaches and stabilizes within the target temperature range uniformly, avoiding localized overheating or underheating. The goal of this stage is to ensure that the expansion of the bushing's inner diameter precisely meets the requirements of the preset assembly clearance.

[0110] Once the monitored temperature stabilizes and the holding time is reached, use an inside diameter gauge to quickly verify the expanded inner hole size, confirming that it is larger than the outer diameter of the machined journal, and that the difference meets the preset assembly clearance. At this point, the bushing is in the customized bushing state after thermal expansion, and subsequent assembly work must be carried out immediately.

[0111] Further, while heating, perform a final cleaning of the mating surfaces of the journal after turning, and apply a small amount of food-grade rust-preventive grease. Quickly move the custom-made bushing, now heated and expanded, to the front end of the journal. Using a simple guide tool or visual inspection, finely adjust the position of the bushing to ensure that its inner bore centerline is precisely aligned with the journal centerline.

[0112] After confirming alignment, the operator, or with the aid of a simple mechanical device, smoothly and evenly pushes the high-temperature bushing along the axial direction of the machined journal towards and fully fits it into the predetermined mating position on the journal. The entire fitting action must be completed quickly and in one go, avoiding any tilting, bumping, or stopping midway to prevent jamming due to localized cooling.

[0113] Once the bushing is in place, it is secured to the journal. At this point, all external heating is stopped, allowing the bushing to cool naturally in the air, or to achieve uniform and slow cooling through controlled ventilation. During cooling, the bushing material shrinks, its inner bore tightly gripping the outer diameter of the journal. The designed target interference fit gradually transforms into significant radial pressure, forming a robust interference fit. When cooled to ambient temperature, the two components have bonded together into an inseparable, newly repaired assembly.

[0114] In summary, the process of heating and expanding to the preset assembly gap, through precise temperature control, transforms interference fittings that are impossible to achieve at room temperature into gap fittings that can be easily completed. The precision of this step directly affects whether the assembly process can proceed smoothly and without damage, serving as a technical hub connecting design and assembly.

[0115] In general, the components are assembled by axially mounting and cooling at high temperature in an axially centered position, and through a natural cooling process, the shrinkage force of the material is completely converted into the designed bonding pressure.

[0116] In summary, the above steps were completed in the harsh environment of wind turbines at high altitudes, in confined spaces, and subject to swaying. Therefore, extremely high standards of operational standardization, proficiency, and timeliness were required. The decisive impact lies in the fact that all the precise results of measurement, calculation, and customization are ultimately solidified into a high-performance mechanical connection through a standardized and controllable thermal mounting process. The successful implementation of this step marks the transformation of online repair from a technical solution into a tangible result.

[0117] S5. Perform geometric tolerance testing on the repair assembly to confirm whether the repair assembly meets the operating standards.

[0118] In this embodiment, the step of performing geometric tolerance testing on the repair assembly to confirm whether the repair assembly meets the operating standards includes: Measure the outer diameter of the repair assembly to verify whether the outer diameter has been restored to the tolerance zone of the original design size; The radial runout of the repair assembly under simulated operating conditions is detected to confirm whether the radial runout is lower than the predetermined standard allowable value.

[0119] Before performing surface rust removal on the worn journal of the wind turbine generator to obtain the machined journal, and measuring the actual diameter value of the machined journal, the process further includes: Anchoring the repair device for the worn journal to the nacelle base of the generator of the wind turbine to construct an integrated in-cabin repair workstation for the generator of the wind turbine.

[0120] Specifically, geometric tolerance detection refers to the measurement and evaluation of the accuracy of the macroscopic geometric shape and positional relationship of mechanical parts in addition to their dimensions.

[0121] Specifically, the operating standard refers to the technical specifications that must be met by the generator journal components in terms of dimensions, shape, positional accuracy, and dynamic balance, which are formulated by the original equipment manufacturer of the wind turbine or specified by relevant national / industry standards.

[0122] Specifically, the outer diameter dimension refers to the actual diameter of the outer cylindrical surface of the journal after fitting the repair assembly, i.e., after inserting the sleeve.

[0123] Specifically, the tolerance zone of the original design dimension refers to the allowable dimension variation range marked for the journal outer diameter on the original design drawing of the wind turbine, usually expressed as the basic dimension ± deviation or tolerance zone code.

[0124] Specifically, the simulated operating conditions refer to the working conditions where the generator rotor rotates at a specific speed without the wind turbine actually being connected to the grid for power generation.

[0125] Specifically, the radial runout refers to the maximum variation of the outer cylindrical surface of the repair assembly in the radial direction relative to a fixed reference point when the repair assembly rotates around its theoretical center line.

[0126] Specifically, the predetermined standard allowable value refers to the maximum allowable radial runout determined based on the requirements for the smooth operation of the wind turbine and the calculation of bearing life.

[0127] Furthermore, select an outer diameter micrometer or an electronic digital display caliper with a suitable range and meeting the accuracy requirements, and perform zero calibration according to the standard gauge before measurement to ensure the accuracy of the instrument itself.

[0128] On the entire length of the mating section of the repair assembly, at least three equally spaced axial cross-section positions are selected. At each cross-section, three points are evenly selected along the circumferential direction for measurement to overcome the possible influence of roundness error.

[0129] Record all the measured values, calculate the average diameter of each cross-section, and use the average value of the three cross-section averages as the final representation value of the outer diameter dimension of the repair assembly. Compare this final value strictly with the tolerance zone of the original design dimension recorded in the maintenance plan and obtained from the original drawing.

[0130] If the measured outer diameter dimension completely falls within the tolerance zone, it is determined that this inspection is qualified; if it exceeds the range, the reasons need to be analyzed to determine whether rework is required.

[0131] Furthermore, using the wind turbine's own drive system or a portable drive device, the generator rotor drives the repair assembly to rotate slowly and smoothly, achieving simulated operating conditions. A magnetic gauge mount is installed on a nearby rigid structure, and the dial indicator probe is vertically and slightly pressed against the center or key position of the outer circumference of the repair assembly.

[0132] Start the rotation and observe and record the maximum and minimum values ​​of the dial indicator pointer during at least three consecutive full rotations. The radial runout is the difference between the maximum and minimum values.

[0133] Compare the measured runout with the predetermined allowable value for that part at the corresponding speed as specified in the maintenance technical specifications or standards. Typically, for large wind turbine generator journals, this allowable value may be in the range of 0.05mm to 0.15mm. If the measured value is lower than the allowable value, the dynamic accuracy is considered qualified; otherwise, the machine must be stopped to find the cause.

[0134] Before the turning measurement begins, a stable and reliable working platform is established in the nacelle of the wind turbine generator.

[0135] Specifically, the repair equipment includes portable lathes, mobile CNC lathes, milling and boring equipment, induction heating devices, measuring instruments, auxiliary tooling fixtures, etc.

[0136] Specifically, the nacelle base refers to the large, heavy steel structure foundation platform inside the wind turbine nacelle used to install the main equipment such as the generator and gearbox.

[0137] Specifically, anchoring refers to using high-strength bolts, pressure plates, special clamps, and other connection methods to firmly and rigidly connect the base of the repair device to the nacelle base to resist nacelle swaying caused by wind turbine operation and external wind loads.

[0138] Specifically, the in-cabin integrated repair workstation refers to a repair work area that is temporarily constructed in the small wind turbine nacelle through the above-mentioned anchoring and system integration. It has multiple functions such as turning, measurement, calculation, processing, heating and testing, and is located in a fixed and relatively stable position.

[0139] Furthermore, the layout of each piece of equipment is pre-planned based on the nacelle space and journal position. The modular repair unit components are then transported into the nacelle using cranes or hoists.

[0140] Align the headstock and tailstock of the portable lathe roughly with the centerline of the generator journal and place them in a suitable position on the nacelle base. Position the mobile CNC lathe, heater, and other equipment in a convenient and safe location.

[0141] Using pre-prepared, appropriately sized and strong anchor bolts, clamping blocks, and shims, securely anchor the base of each piece of equipment to the steel structure of the nacelle base. During tightening, use a level to ensure the equipment's reference surface is level and that there is no wobbling after tightening. Connecting rods may also be needed to interconnect the equipment to enhance overall rigidity.

[0142] Connect the equipment's power supply, control system, and air circuit. Perform final alignment and fine-tuning of the portable lathe's spindle and journals. Verify the zero point of the measuring instruments. At this point, a fully functional and robust integrated in-cabin repair workstation is complete, providing a quiet zone free from environmental vibrations for all subsequent precision operations.

[0143] In summary, quality inspection provides quantitative and undisputed proof of repair quality. This ensures that only fully compliant components can be returned to service, fundamentally eliminating the risk of secondary failures due to poor repair quality and greatly enhancing owners' confidence in online repair technology.

[0144] In summary, within the swaying high-altitude nacelle, any micron-level machining and measurement requires an extremely stable work platform. Anchoring the integrated repair workstation rigidly connects the maintenance equipment to the nacelle's largest inertial mass, effectively filtering out dynamic interference from wind turbine tower sway and unit operation. This transforms a precision mechanical repair task impossible to perform on a swaying platform into a standard operation that can be executed in a locally stable machine tool environment. This is the physical basis for the high precision and high reliability of this online repair method, serving as a bridge between the harsh high-altitude environment and ground-based workshop-level processes.

[0145] The embodiments of this application can acquire and process relevant data based on artificial intelligence technology. Artificial intelligence (AI) refers to the theories, methods, technologies, and application systems that use digital computers or machines controlled by digital computers to simulate, extend, and expand human intelligence, perceive the environment, acquire knowledge, and use that knowledge to obtain optimal results.

[0146] Furthermore, the inclusion of a single word does not exclude other units or steps, and the singular does not exclude the plural. Terms such as "first," "second," etc., are used to indicate names and do not indicate any particular order.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for online bushing repair of wind turbine generator journals, characterized in that, The method includes: S1. Remove rust from the worn journal of the wind turbine generator to obtain the machined journal of the worn journal, and measure the actual diameter value of the machined journal. S2. Calculate the target bushing interference fit of the worn journal based on the measured diameter value of the journal, the predetermined transmission torque requirement, and the material property parameters of the worn journal. S3. Based on the measured diameter of the journal and the interference fit of the target bushing, determine the bushing machining dimensions of the worn journal, and based on the bushing machining dimensions, prepare a customized bushing with the bushing machining dimensions. S4. The customized bushing is heated and expanded, and the heated and expanded customized bushing is press-fitted with the machined journal to generate the repair assembly of the worn journal; S5. Perform geometric tolerance testing on the repair assembly to confirm whether the repair assembly meets the operating standards.

2. The method for online bushing repair of wind turbine generator journals as described in claim 1, characterized in that, The process of surface rust removal from the worn journal of the wind turbine generator to obtain a machined journal, and measuring the actual diameter of the machined journal, includes: The worn journal is polished and cleaned to obtain a clean journal. The clean journal is machined to a fixed dimension to obtain the machined journal of the worn journal. In the axial direction of the machined journal, the journal diameter values ​​at three different positions of the machined journal are measured, and the average value of the journal diameter values ​​is calculated to obtain the actual measured journal diameter value of the machined journal.

3. The method for online bushing repair of wind turbine generator journals as described in claim 1, characterized in that, The step of calculating the target bushing interference fit of the worn journal based on the measured diameter value of the journal, the predetermined transmission torque requirement, and the material property parameters of the worn journal includes: Calculate the minimum engagement pressure required between the worn journal and the custom bushing based on the predetermined transmission torque requirements; Based on the minimum engagement pressure, the measured diameter of the journal, and the material elastic parameters of the worn journal, calculate the minimum effective interference fit required for the worn journal to mate with the custom bushing. Based on the yield strength of the journal material of the worn journal and the yield strength of the bushing material of the custom bushing, calculate the maximum permissible contact pressure between the worn journal and the custom bushing. Based on the smaller of the maximum permissible engagement pressure, the measured diameter of the journal, and the material elasticity parameters, calculate the maximum permissible effective interference fit between the worn journal and the custom bushing. Within the feasible range formed by the minimum effective interference and the maximum effective interference, the target bushing interference of the worn journal is calculated in combination with a preset assembly safety factor.

4. The method for online bushing repair of wind turbine generator journals as described in claim 3, characterized in that, The target insert interference includes: The rated output power and rated speed of the wind turbine generator determine the required transmission torque. The journal Lamé coefficient of the worn journal is determined based on the journal Poisson's ratio. The bushing Lamé coefficient of the custom bushing is determined based on the bushing Poisson's ratio and the journal ratio of the custom bushing. The target bushing interference is calculated based on the transmission torque requirement, the journal Lamé coefficient, and the bushing Lamé coefficient.

5. The method for online bushing repair of wind turbine generator journals as described in claim 1, characterized in that, The process of determining the bushing machining dimensions of the worn journal based on the measured diameter of the journal and the target bushing interference fit, and then preparing a customized bushing with the specified machining dimensions based on those dimensions, includes: Based on the measured diameter of the journal, the interference fit of the target bushing, and the deformation coordination relationship between the worn journal and the custom bushing under the fitting pressure, the inner diameter machining dimension of the custom bushing is obtained by inverse solution. Based on the inner diameter machining dimensions and the preset bushing strength safety requirements, calculate the outer diameter machining dimensions of the customized bushing; Based on the inner diameter machining dimensions and the outer diameter machining dimensions, a customized bushing with the specified bushing machining dimensions is prepared.

6. The method for online bushing repair of wind turbine generator journals as described in claim 5, characterized in that, The deformation coordination relationship includes: Under the specified fitting pressure, the sum of the radial shrinkage of the worn journal and the radial expansion of the custom bushing is equal to the interference fit of the target bushing.

7. The method for online bushing repair of wind turbine generator journals as described in claim 1, characterized in that, The formula for calculating the machining dimensions of the bushing is: ； in, The outer diameter machining dimension of the bushing is the machining dimension. The inner diameter of the custom bushing is machined to the specified dimensions. For the wall thickness safety factor, The maximum permissible engagement pressure between the worn journal and the custom bushing. The yield strength of the custom bushing.

8. The method for online bushing repair of wind turbine generator journals as described in claim 1, characterized in that, The process of heating and expanding the custom bushing, and then press-fitting the expanded custom bushing with the machined journal to generate a repair assembly for the worn journal, includes: During the heating process of the custom bushing, the custom bushing is uniformly expanded to a preset assembly gap according to the heating process parameters of the custom bushing, so as to obtain the heated and expanded custom bushing. The customized bushing, after being heated and expanded, is fitted along the axial direction of the machined journal to generate a repair assembly for the worn journal.

9. The method for online bushing repair of wind turbine generator journals as described in claim 1, characterized in that, The step of performing form and position tolerance testing on the repair assembly to confirm whether the repair assembly meets the operating standards includes: Measure the outer diameter of the repair assembly to verify whether the outer diameter has been restored to the tolerance zone of the original design size; The radial runout of the repair assembly under simulated operating conditions is detected to confirm whether the radial runout is lower than the predetermined standard allowable value.

10. The method for online bushing repair of wind turbine generator journals as described in claim 1, characterized in that, Before performing surface rust removal on the worn journal of the wind turbine generator to obtain the machined journal, and measuring the actual diameter value of the machined journal, the process further includes: The wear journal repair device is anchored to the nacelle base of the wind turbine generator to construct an integrated in-nacelle repair workstation for the wind turbine generator.

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