Optimization method of wind power bearing

Abstract

The invention relates to an optimization method of a wind power bearing, and belongs to the technical field of bearing optimization. According to the method, firstly, bearing parameters with the fatigue life conforming to the specification are obtained, then the deformation condition of an inner ring raceway is considered, the bearing parameters which are closer to the reality are obtained, contact stresses of corresponding rollers and the inner ring raceway under # imgabs0 #, # imgabs1 # and # imgabs2 # are obtained, and the three accurate contact stresses conforming to the corresponding specification are taken as the target. According to the method, the roller surface repair amount in the roller parameters is adjusted to optimize the wind power bearing, the obtained bearing parameters, the contact stress of the roller corresponding to the bearing parameters and the inner ring raceway and the error of the fatigue life are smaller, and then the accuracy of the bearing optimization result is improved.

Description

Technical Field

[0001] The invention relates to an optimization method for a wind power bearing, and belongs to the technical field of bearing optimization. Background Art

[0002] Wind power technology is rapidly developing worldwide. To meet the demands of offshore wind power applications, wind turbines are becoming increasingly larger, currently exceeding 20MW. Compared to onshore wind energy resources, offshore wind energy resources are more abundant, resulting in relatively large and prolonged wind loads on offshore wind turbines. Consequently, offshore wind turbines are larger in size, placing higher demands on the long-term safety performance of their components.

[0003] The wind turbine main shaft is a large rotating shaft connecting the fan hub to the speed-increasing gearbox generator. The front end of the wind turbine main shaft bearing must bear the complex multi-degree-of-freedom loads caused by the rotation of the front blades, while the rear end of the bearing must withstand the weight of the speed-increasing gearbox generator and the unstable impact loads of the entire system. Due to factors such as the large size of the wind turbine and the limited installation location, the cost of repairing and replacing the bearings is very high. Therefore, the reliable, stable operation and long life of the bearings are crucial to the overall operation of the wind turbine. To ensure reliable, stable operation and long life of the bearings, in addition to detailed calculation of the bearing internal parameters during the design phase, more factors must be considered when verifying bearing performance.

[0004] A Chinese invention patent application with application publication number CN107729597A and publication date February 23, 2018, discloses a spindle bearing raceway calibration tool that directly performs equivalent processing on sequential loads and LDD load spectra. Specifically, the tool equates multiple load groups into a single load and applies it to the wheel hub, calculating the bearing load. The bearing life and contact stress are then calculated based on the standard. However, the bearing load calculated by applying only one load group exhibits a significant error compared to the actual load. Due to the large error in the bearing load, the accuracy of the bearing life and contact stress calculated in this solution, all based on ISO standard methods, is relatively low. The accuracy of the bearing performance evaluation results based on empirical evaluation is also relatively low. In other words, the bearing load, bearing life, and contact stress obtained using this solution all deviate significantly from the actual load. Furthermore, the calculation process of this solution is based on a rigid body, so the calculated results are likely to be larger than the actual engineering value. If the calculation is based on a flexible body, the accuracy of the results will be even worse. For general projects, this solution has a certain reference value, but for more complex marine working conditions and for wind turbines that require higher safety and stability, more accurate and rigorous algorithms are needed.

[0005] A Chinese invention patent application with application publication number CN107590356A and a publication date of January 16, 2018, discloses a method and storage device for automatically selecting main shaft bearings for wind turbine generator systems. This solution establishes a bearing database and evaluates bearings based on calculated bearing loads. While this method allows for rapid bearing selection and evaluation, it is only applicable to bearing application organizations. Because it lacks bearing optimization capabilities, it is not suitable for optimizing existing bearings or designing new bearings.

[0006] A Chinese invention patent application with application publication number CN107688716A and application publication date of February 13, 2018, discloses a parameter optimization method for hollow cylindrical roller bearings based on load distribution and fatigue life. This optimization method mainly optimizes the parameters of hollow cylindrical roller bearings whose fatigue life is less than the expected fatigue life. It only provides the conditions that meet the bearing optimization but does not provide optimization-related solutions.

[0007] In summary, faced with complex offshore working conditions and the trend towards larger wind turbines, an optimization method for bearings that ensures reliable and stable operation and long life has become an industry need.

[0008] Currently, bearing optimization can be achieved through finite element simulation software. Although the bearing optimization scheme using finite element simulation software can take into account the deformation effect of bearing installation interference on the ring and the expansion deformation effect caused by temperature rise during bearing operation, it cannot complete the input calculation of multiple groups of multi-degree-of-freedom loads. Even if only one group is calculated, due to the complexity of the wind turbine model and bearings, the calculation takes a very long time and the final optimization result cannot be obtained efficiently. Therefore, it is not suitable for the rapid iteration of engineering design schemes. In addition, when only one group of loads or a small number of groups of loads are used to optimize the bearing, since one or a small number of groups of loads retain fewer characteristics of the actual working conditions, it is impossible to fully restore the actual working conditions of the bearing, resulting in a large deviation between the bearing parameters optimized by this method and the actual ones.

[0009] Transmission simulation software such as Romaxwind can calculate the input of more sets of multi-degree-of-freedom loads and quickly calculate bearing life and contact stress. However, its bearing model calculation does not consider the influence of internal deformation, resulting in a large deviation between the bearing parameters optimized by this method and the actual ones. Summary of the Invention

[0010] The object of the present invention is to provide a method for optimizing a wind power bearing, so as to solve the problem that the accuracy of optimization results of existing wind power bearings is relatively low.

[0011] To achieve the above object, the solution of the present invention includes: A method for optimizing a wind power bearing according to the present invention comprises the following steps: The bearing model constructed according to the initial parameters of the bearing is loaded with the limit load spectrum and fatigue load spectrum respectively to obtain the following: the maximum load of the bearing roller under the limit load spectrum And fatigue life and fatigue stress of bearings under fatigue load spectrum; Adjust the initial parameters with the goal of fatigue life meeting the requirements to obtain the optimized parameters; Determine the inner ring raceway parameters after deformation based on the inner ring raceway parameters in the optimization parameters; sort the time corresponding to the load step in the fatigue load spectrum according to the size of the fatigue stress corresponding to it, and determine the maximum roller load corresponding to the first and last fatigue load spectra corresponding to the first specified proportion in the total time sorted from large to small or the last specified proportion in the total time sorted from small to large. ; The roller parameters in the optimization parameters and the inner ring raceway parameters after deformation are calculated. The corresponding contact stress between the bearing roller and the inner ring raceway ; by With the goal of meeting the corresponding regulations, the roller surface maintenance amount in the roller parameters is adjusted to obtain the final parameters of the bearing.

[0012] Furthermore, the deformed inner ring raceway parameters include the diameter and surface shape of the inner ring raceway, which are obtained by theoretical calculation based on the slicing method.

[0013] Furthermore, All calculations are based on the finite length line contact theory.

[0014] Furthermore, the bearing model adopts a flexible simulation model.

[0015] Furthermore, the steps of the optimization method are implemented using transmission simulation software.

[0016] Furthermore, factors causing deformation of the inner ring raceway include interference fit of the bearing and temperature rise during bearing operation.

[0017] Furthermore, the proportion is stipulated to be 20%.

[0018] Furthermore, the number of equivalent groups of the ultimate load spectrum ranges from 10 to 25.

[0019] Furthermore, the number of equivalent groups of the fatigue load spectrum ranges from 100 to 500.

[0020] Beneficial effects of the present invention: This invention is a pioneering invention that provides an optimization method for wind power bearings. The method first constructs a bearing model based on the initial parameters of the bearing, and loads the model with the limit load spectrum and fatigue load spectrum to obtain the maximum load of the roller of the bearing under actual limit working conditions. and the fatigue life and fatigue stress of the bearing under actual fatigue working conditions, and by adjusting the initial parameters of the bearing, obtain the optimized parameters of the bearing that meet the bearing life requirements under the above actual working conditions; Secondly, to make the optimized parameters of the bearing more realistic, the deformation of the inner ring raceway under actual working conditions is considered and the parameters of the inner ring raceway after deformation are determined; The time corresponding to the load step in the fatigue load spectrum is also sorted according to the size of the fatigue stress corresponding to the fatigue load spectrum. Based on the fact that the time when the fatigue stress exceeds the limit value specified by the industry does not exceed the specified proportion (specified proportion), the maximum roller load corresponding to the first fatigue load spectrum in the first specified proportion is selected from the total time when the fatigue stress is sorted from large to small, or the maximum roller load corresponding to the first fatigue load spectrum in the second specified proportion is selected from the total time when the fatigue stress is sorted from small to large. Maximum roller load corresponding to the last fatigue load spectrum ; Finally, based on the roller parameters and the inner ring raceway parameters after deformation in the bearing parameters that meet the bearing life requirements, the following is calculated: Contact stress between lower bearing roller and inner ring raceway 、 Contact stress between lower bearing roller and inner ring raceway and Contact stress between lower bearing roller and inner ring raceway ,by 、 and With the goal of meeting the corresponding regulations, the roller surface repair amount in the roller parameters is adjusted to obtain the final parameters of the bearing as the optimization result.

[0021] The present invention first obtains bearing parameters that meet the requirements for fatigue life, and then considers the deformation of the inner ring raceway to obtain more practical bearing parameters. 、 and The contact stress between the corresponding roller and the inner ring raceway is calculated. With the goal of ensuring that the three accurate contact stresses here meet the corresponding regulations, the roller surface repair amount in the roller parameters is adjusted to achieve bearing optimization. The errors in the obtained bearing parameters, the contact stress between the roller and the inner ring raceway corresponding to the bearing parameters, and the fatigue life are smaller, thereby improving the accuracy of the bearing optimization results. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the optimization flow chart for wind power bearings; Figure 2 It is a schematic diagram of the flexible simulation model; Figure 3 It is a schematic diagram of the bearing inner ring raceway coordinate system and its model; Figure 4 This is a graph showing the contact stress of the bearing roller surface before and after optimization.

[0023] Description of reference numerals: 1. Wind load; 2. Bearing A; 3. Bearing B; 4. Gearbox gravity. DETAILED DESCRIPTION

[0024] In order to solve the problems in the background technology, the present invention not only restores the actual working conditions of the bearing, but also takes into account the influence of deformation during bearing operation on contact stress and fatigue life, and optimizes the bearing parameters based on the load spectrum and bearing parameters that are more in line with the actual working conditions, so as to improve the accuracy of the bearing optimization results.

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0026] An embodiment of a method for optimizing a wind power bearing: A method for optimizing a wind power bearing comprises the following steps: The bearing model is constructed based on the initial parameters of the bearing, and the ultimate load spectrum and fatigue load spectrum are loaded on the bearing model respectively to obtain the maximum load of the bearing roller under the ultimate load spectrum. And fatigue life and fatigue stress of bearings under fatigue load spectrum.

[0027] With the goal of ensuring that the fatigue life of the bearing meets the requirements, the initial parameters of the bearing are adjusted to obtain the optimized parameters of the bearing that meet the requirements of the bearing fatigue life.

[0028] The inner ring raceway parameters after deformation are determined based on the inner ring raceway parameters in the optimization parameters.

[0029] Sort the time corresponding to the load step in the fatigue load spectrum by the size of the corresponding fatigue stress to obtain the total time, and determine the maximum roller load corresponding to the first fatigue load spectrum corresponding to the first prescribed proportion of fatigue stress in the total time sorted from large to small. Maximum roller load corresponding to the last fatigue load spectrum , or determine the maximum roller load corresponding to the first fatigue load spectrum corresponding to the total time in which the fatigue stress is sorted from small to large in the total time Maximum roller load corresponding to the last fatigue load spectrum .

[0030] about 、 , which can also be expressed as: Sort the time corresponding to the load step in the fatigue load spectrum corresponding to the fatigue stress in order of size to obtain the time scale reflecting the fatigue stress-fatigue load spectrum, and determine the maximum roller load corresponding to the first fatigue load spectrum in the previous prescribed proportion corresponding to the fatigue stress sorted from large to small in the time scale. Maximum roller load corresponding to the last fatigue load spectrum Alternatively, determine the maximum roller load corresponding to the first fatigue load spectrum in the specified proportion corresponding to the fatigue stress sorted from small to large in the time scale Maximum roller load corresponding to the last fatigue load spectrum .

[0031] The roller parameters in the optimization parameters and the inner ring raceway parameters after deformation are calculated. Contact stress between lower bearing roller and inner ring raceway 、 Contact stress between lower bearing roller and inner ring raceway and Contact stress between lower bearing roller and inner ring raceway ; by 、 and The goal is to meet the corresponding regulations, adjust the roller surface repair amount in the roller parameters, and obtain the roller surface that meets the corresponding regulations. 、 and The corresponding bearing parameters are used as the final parameters of the optimized bearing.

[0032] Among them, the limit load spectrum and fatigue load spectrum can restore the actual working conditions of the bearing during operation.

[0033] The initial, optimized, and final bearing parameters all include the roller parameters, inner ring raceway parameters, outer ring raceway parameters, and cage parameters within the bearing. Roller parameters include roller size, number of rollers, and roller surface wear; inner ring raceway parameters include the inner ring raceway taper angle; and outer ring raceway parameters include the outer ring raceway taper angle.

[0034] When the initial parameters of the bearing are the bearing parameters to be optimized, the final parameters of the bearing are the optimization results of the wind power bearing to be optimized. When the initial parameters of the bearing are the bearing parameters to be designed, the final parameters of the bearing are the design results of the bearing to be designed.

[0035] Specifically, the inner ring raceway parameters before and after deformation also include the diameter and surface shape of the inner ring raceway. The inner ring raceway parameters after deformation are obtained by theoretical calculation based on the slicing method.

[0036] Specifically, 、 and All calculations are based on the finite length line contact theory.

[0037] Specifically, the bearing model adopts a flexible simulation model to provide fast and reliable calculation software to meet the rapid iteration requirements of engineering design.

[0038] Specifically, the steps of the optimization method are implemented using transmission simulation software.

[0039] Specifically, the deformation factors of the inner ring raceway include bearing interference mounting and temperature rise during bearing operation.

[0040] Considering that the time when fatigue stress exceeds the limit value specified by the industry does not exceed the specified proportion (specified proportion), since the specified proportion specified by the industry is 20%, the specified proportion is taken as 20%. There is also an existing industry specified proportion of 15%, so the specified proportion can also be taken as 15%.

[0041] In order to restore the extreme working conditions of the bearing as much as possible, the equivalent number of groups of the extreme load spectrum used ranges from 10 to 25.

[0042] In order to restore the fatigue conditions that occur during bearing operation as much as possible, the equivalent number of groups of the fatigue load spectrum used ranges from 100 to 500.

[0043] This wind turbine bearing optimization method, applied to wind turbine main shafts, employs two key judgments to iteratively optimize bearing parameters. The first judgment determines the bearing life (fatigue life) for iterative optimization of the bearing parameters, primarily through simulation calculations. The second judgment determines the bearing's internal stress value (internal stress refers to the contact stress between the bearing rollers and the inner ring raceway) for iterative optimization of the roller surface finish within the bearing parameters. This process considers the effects of bearing interference and operating temperature on the internal structure and is implemented through theoretical calculations combined with computer programming and numerical analysis. This iterative optimization method, based on these two judgments, optimizes bearing parameters, ultimately resulting in a safe, stable, and long-life bearing suitable for the complex load conditions of wind turbine main shafts.

[0044] The following is a detailed description of the optimization of wind power bearings with reference to the accompanying drawings: like Figure 1 The specific implementation steps are as follows: Step 1: Preliminary design of bearing parameters.

[0045] The preliminary design of the bearing is based on past experience. The designed bearing parameters mainly include the roller size inside the bearing, the number of rollers, the inner and outer ring taper angles, the cage, etc.

[0046] This step relies on the technician's experience and affects the number of iterations and calculation time in subsequent steps. Therefore, bearing technicians should have design capabilities and previous experience.

[0047] At the same time, when setting the internal parameters of the bearing, the roller surface modification should be preliminarily set in this step. Usually, it is set according to a certain proportion of the rated load calculated for the bearing. The subsequent iteration of the roller parameters should be based on this step. The specific modification equation of the roller surface depends on the experience of the bearing design unit. It may be an arc, an arc plus a straight line, a logarithm, a quasi-logarithm, or other modification curve types, and is not limited to symmetrical modification or asymmetrical modification. However, roller surface modification is necessary, which has a significant impact on the internal stress and service life of the bearing in the bearing application. Therefore, the setting of this step cannot be omitted.

[0048] Specifically, during the initial bearing design, based on past experience in wind turbine main shaft bearing design, the roller dimensions, number of rollers, inner and outer ring taper angles, and cage were initially determined. Roller surface modification is based on the classic Lundberg logarithmic equation, where the modification load factor is 0.2 times the bearing's rated dynamic load. The specific modification equation can be found in relevant literature. This modification method is widely considered the most effective and widely used. The iteration of the modification parameters described later in this paper achieves superior computational speed.

[0049] Step 2: Prepare the ultimate load spectrum and fatigue load spectrum.

[0050] Load equivalence is an important part of wind turbine calibration. In order to restore the actual working conditions as much as possible, the load should retain the characteristics of the actual working conditions as much as possible. Obviously, the more equivalent groups there are, the closer it will be to reality, but computing resources are limited, and more loads mean longer computing time and greater computer power. Therefore, this solution will equate the extreme load spectrum to 16 groups, and the fatigue load spectrum needs to be equivalent to 100 to 500 groups. The specific equivalence method can use the existing patented technology with the authorization announcement number CN117592221B, which will not be repeated here. Compared with the equivalence to 1 group, the optimization results of the present invention will be more referenceable.

[0051] Specifically, the limit loads of this solution are provided by the wind turbine manufacturer, and the fatigue load spectrum is equivalent based on the data provided by the manufacturer, and finally equivalent to 421 groups.

[0052] Step 3: Establish a flexible simulation model of the spindle bearing and load the fatigue load spectrum and the limit load spectrum respectively.

[0053] This step is completed using computer software. This solution uses 3D software to draw assembly components such as the hub and spindle. A flexible mesh is created using meshing tools. Transmission simulation software Romaxwind is imported to create a bearing model and create a flexible mesh for the bearing rings. The ultimate load and fatigue load from step 2 are then input for flexible calculation. This step is not limited to this modeling method. Because the model is flexible, the results are more realistic than with a rigid model.

[0054] The model has two bearings, and both bearings should be calculated. Since the routes are the same, this manual only describes them as "bearings" and no longer distinguishes between bearing A and bearing B. The methods below are applicable to both bearings.

[0055] The flexible simulation model of this step is as follows: Figure 2 As shown, it includes wind load 1, bearing A2, bearing B3 and gearbox gravity 4. Bearing A2 mainly bears the multi-degree-of-freedom complex load brought by the rotation of the front blade due to wind load 1, and bearing B3 mainly bears the weight load brought by the rear gearbox gravity 4.

[0056] This step is not limited to this modeling and simulation method. Among the wide range of commercial simulation software, any commercial software that has flexible functions, can calculate more than 100 sets of loads, and can output bearing life and stress results can be applied to this solution.

[0057] Step 4: Obtain the bearing life results (bearing fatigue life) and fatigue stress under the fatigue load spectrum; obtain the maximum load of the bearing roller under the limit load spectrum .

[0058] In this step, the bearing life must be output as a life value that complies with ISO standards. If the output is stress times due to simulation software issues, life conversion should be performed.

[0059] The number of fatigue stress groups and the number of fatigue life groups both depend on the equivalent number of fatigue load spectrum groups, that is, the equivalent number of fatigue load spectrum groups is equal to the number of fatigue stress groups and the number of fatigue life groups. Since there are 100 to 500 groups of fatigue loads, there will also be 100 to 500 corresponding groups of fatigue stresses.

[0060] Fatigue life and fatigue stress are derived based on the bearing parameters (including the surface modification of the bearing rollers) set in Step 1. Although surface modification does affect bearing life and will be iteratively optimized later, its effect on bearing life is not calculated.

[0061] In this step, the maximum load of the bearing roller under the limit load is obtained In fact, it includes the normal load and torque load on the roller surface, which are generated by the contact between the roller and the inner ring raceway and the outer ring raceway respectively. Therefore, the maximum load of the bearing roller under the limit load is It actually contains four values: the contact force between the roller and the inner ring, the contact force between the roller and the outer ring, the torque between the roller and the inner ring, and the torque between the roller and the outer ring. The above results are all obtained from the simulation calculation in step 3.

[0062] Step 5: Determine the bearing life.

[0063] If the bearing life result meets the required value (specification or user), proceed to the next step; otherwise, return to step 1 and adjust the bearing parameters until the bearing life result meets the requirements, and then output the roller parameters.

[0064] Because lifespan is the primary guarantee of bearing performance, we first conducted an initial iteration targeting bearing lifespan, optimizing key bearing parameters. Once lifespan was met, we iterated on the bearing's internal stress values and optimized the surface modification parameters for the internal rollers and raceways.

[0065] While the simulation results can also reveal internal bearing stress values, to ensure more realistic and reference-based results, subsequent stress calculations must account for the deformation of the bearing rings caused by interference fit during installation, as well as the expansion and deformation caused by temperature rise during bearing operation. These factors cannot be accounted for in the current simulation. This means that the simulated stress values used in this solution are initial values, requiring further calculations to correct them.

[0066] While current finite element simulation software can account for interference and temperature-rise deformation, it cannot complete the input calculations for 100 to 500 sets of multi-degree-of-freedom loads. Even calculating a single set requires a very long time due to the complexity of the wind turbine model and bearings, making it unsuitable for rapid iteration of engineering design solutions. Transmission simulation software such as Romaxwind can calculate 100 to 500 load spectra and quickly calculate bearing life and stress, but its bearing model calculations do not consider the effects of internal deformation. Therefore, this solution proposes a route that first uses simulation for life calculations, followed by iterative optimization of bearing internal stresses through theoretical calculations.

[0067] Specifically, after performing 421 equivalent calculations for the fatigue load spectrum, the bearing life results shown in Table 1 were obtained. The "e" in Table 1 represents scientific notation; e5 refers to 10 to the fifth power, and e6 refers to 10 to the sixth power. Hours is the unit of life.

[0068] Table 1 According to regulations, when L10m>130,000h (hours) and L10mr>175,000h, the bearing parameters are considered to meet the life requirements.

[0069] Based on the fact that the surface stress of the roller bearing the maximum load under extreme fatigue does not exceed the limit value, according to industry experience, the limit value here is stipulated as 2800MPa.

[0070] Under fatigue load, the stress time exceeding the limit value shall not exceed the required proportion X%. According to industry experience, the limit value here is stipulated as 1500MPa, and the required proportion X% is stipulated as 20%.

[0071] The surface stress of the roller bearing the maximum load under fatigue load does not exceed the limit value. According to industry experience, the limit value here is stipulated as 1650MPa.

[0072] Step 6: Select the loads that take up the top X% of the time.

[0073] Based on the results of step 4, the time corresponding to the load step in the fatigue load spectrum is sorted in descending order of fatigue stress to obtain a time scale reflecting fatigue stress-fatigue load spectrum. In this time scale, the load spectrum number corresponding to the first specified proportion X% (time proportion of the first X%) corresponding to the fatigue stress sorted from large to small is 1...k.

[0074] It should be noted that this refers to the time percentage, not the group percentage. The fatigue load spectrum described above is equivalent to 421 groups, and the time corresponding to each load step in the fatigue load spectrum should be calculated. The top X% of the time percentage is preferably 20%. Therefore, the number of load groups with the top 20% of the time percentage for bearing A is 117.

[0075] Step 7: Obtain the maximum load of the bearing roller corresponding to load spectrum number 1 and k and .

[0076] Same as step 4, and They represent four values respectively, namely the contact force between the roller and the inner ring, the contact force between the roller and the outer ring, the torque between the roller and the inner ring, and the torque between the roller and the outer ring.

[0077] Step 8: Based on the slicing method, the diameter and surface shape of the deformed raceway are calculated considering the influence of bearing interference and temperature rise.

[0078] Based on thick-walled ring theory, this section first slices the bearing ring to establish an equation for the raceway diameter. Taking into account the effects of bearing interference and temperature rise, each slice is calculated to determine the raceway diameter and surface shape after total deformation.

[0079] like Figure 3 As shown, the coordinate system of the inner ring of the tapered roller bearing is established, and the equation for the raceway radius is: The equation for the inner ring raceway deformation considering the influence of interference is: The equation for the inner ring raceway deformation considering the effect of temperature rise is: If the thermal expansion coefficient of the shaft is the same as that of the inner ring, the raceway radius equation is updated to: If the thermal expansion coefficient of the shaft is different from that of the inner ring, the interference Perform the following calculations: Then use Instead of the equation of the inner ring raceway deformation considering the influence of interference The value is calculated again, and the equation is used to calculate the inner ring raceway deformation considering the influence of interference, the inner ring raceway deformation considering the influence of temperature rise, and the raceway radius when the thermal expansion coefficient of the shaft is the same as that of the inner ring.

[0080] In the above formula, is the raceway radius, is the horizontal coordinate value of the raceway section, is the large end diameter of the inner ring raceway, is the horizontal length of the raceway, is the raceway semi-cone angle, is the change in raceway radius due to interference, is the inner diameter of the inner ring, is the interference, 、 are the elastic moduli of the bearing inner ring and the shaft, 、 are the elastic moduli of the bearing inner ring and the shaft, is the inner diameter of the shaft, is the deformation caused by the temperature rise of the inner ring raceway, is the thermal expansion coefficient of the inner ring material, is the operating temperature, Normal temperature (usually 20°C), is the thermal expansion coefficient of the shaft material, is the radius of the raceway after thermal expansion.

[0081] Since the thermal expansion coefficients of the shaft and outer ring are the same, the interference increase is 0, so there is no need to calculate the interference effect after the temperature rise. If the thermal expansion coefficients of the shaft and inner ring are different, it is necessary to recalculate the interference after the temperature rise and calculate the impact after the interference.

[0082] Specifically, for bearing A, with an interference fit of 1.15mm and an operating temperature of 65°C, the inner ring raceway deformation from the small end to the large end is calculated to be 0.435-0.465mm, and the raceway semi-cone angle changes by 0°32″. Therefore, the deformation value must be added to the y value of the deformed raceway to obtain the radius of the raceway slice.

[0083] Step 9: According to the load 、 and , calculate the contact stress between the bearing roller and the inner ring raceway of a single roller surface.

[0084] This section considers the original surface modification, the deformation from step 8, and the tilting clearance caused by the contact torque to comprehensively calculate the contact clearance. The contact stress between the bearing rollers and the inner ring raceway is calculated based on the finite length line contact theory. This calculation requires computer programming. There are various methods for calculating the contact stress between the bearing rollers and the inner ring raceway in the industry, and the finite length line contact theory is one of them.

[0085] This technical solution calculates the contact stress as follows according to the flexibility coefficient method equation: The contact area of the two contact bodies is divided into The half length of the rectangular unit is , the half-width is .

[0086] The equilibrium equation is: In the above formula, is the flexibility coefficient, which represents the unit In the unit the impact on is the relative displacement of the two contact bodies; is the elastic modulus of the two contact bodies; For unit Contact stress on is the surface morphology equation of the contact body; is the total load force; For unit in The geometric center of the direction; For unit in The geometric center of the direction; For unit In the unit The geometric center of the direction; For unit In the unit The geometric center of the direction; is the profile function of the contact surface with respect to The derivative of is the profile function of the contact surface with respect to The derivative of . Solving the equilibrium equation requires numerical programming. For details on the flexibility coefficient method, see Ma Jiaju's 1992 paper "Roller Crown Design."

[0087] Specifically, this step utilizes mathematical software MATLAB to compile a numerical calculation program.

[0088] Step 10: Determine contact stress.

[0089] According to the judgment conditions set, the load The contact stress value Not exceeding the required value, which is preferably 2800MPa; load The contact stress value Not exceeding the required value, which is preferably 1650MPa; load The contact stress value The required value should not exceed 1500 MPa. If any of these conditions are not met, adjust the roller surface modification amount, specifically increasing or decreasing it. After adjustment, return to step 9 and rebuild the gap equation for calculation. If all conditions are met, the iteration ends.

[0090] Contact stress curves before and after ultimate load optimization, such as Figure 4 As shown in Figure 3, after optimization, the contact stress is lower than the set 2800 MPa.

[0091] Step 11. After completing the above steps, the iterative design of the bearing is completed and the bearing engineering drawings can be output.

[0092] The final optimized bearing solution has been tested and verified to be suitable for the proposed engineering conditions. The developed bearings have achieved good economic benefits. This solution is suitable for optimizing main shaft bearings of large wind turbines and lays the foundation for the development of future deep-sea wind turbines.

[0093] Through the above steps, bearing parameters were iteratively designed based on fatigue life results. Furthermore, bearing contact stresses were theoretically calculated under extreme load and fatigue load conditions, and roller surface modification parameters (roller surface profile modification parameters) were iteratively designed. This ultimately led to the optimization of the bearing. This approach provides evaluation criteria for each iteration, taking into account more comprehensive factors and resulting in more reliable bearing designs. This approach overcomes shortcomings in existing technologies for optimizing main shaft bearings for medium and large wind turbines, resulting in more rational bearing optimization and results that are more consistent with engineering practice. This approach is suitable for the reliability design and evaluation of main shaft bearings for future large and ultra-large wind turbines, and can provide technical support for the safe operation of future large-megawatt wind turbines.

[0094] This method uses a relatively large number of load spectra to restore the actual working conditions of the bearing as much as possible, and considers the deformation effect of the bearing installation interference on the ring and the expansion deformation effect caused by the temperature rise during the operation of the bearing for bearings that meet the bearing life requirements, so as to obtain the contact stress between the roller and the inner ring raceway under the bearing parameters that are more in line with the actual conditions. The bearing is optimized based on the accurate contact stress, and the errors of the obtained bearing parameters, the contact stress between the roller and the inner ring raceway corresponding to the bearing parameters, and the fatigue life are smaller, thereby improving the accuracy of the bearing optimization results.

[0095] Because the technical solution of this invention involves numerous computational processes, detailed implementation methods are not provided. For example, reference can be made to relevant professional reference books on modeling and simulation techniques; deformation and stress calculations involve numerical iterative calculations using computer programming. Regarding the entire technical approach, adjustments to the sequence, calculation coefficients, and constraints based on understanding, as well as integration of this approach into design software, are all considered within the technical scope of this invention. This technical solution is not limited to the specified tapered bearing.

Claims

1. A method for optimizing a wind power bearing, characterized in that: The steps include: The bearing model constructed according to the initial parameters of the bearing is loaded with the limit load spectrum and fatigue load spectrum respectively to obtain the following: the maximum load of the bearing roller under the limit load spectrum And fatigue life and fatigue stress of bearings under fatigue load spectrum; Adjusting the initial parameters with the goal of the fatigue life meeting the requirements to obtain optimized parameters; Determine the inner ring raceway parameters after deformation based on the inner ring raceway parameters in the optimization parameters; sort the time corresponding to the load step in the fatigue load spectrum according to the size of the fatigue stress corresponding to it, and determine the maximum roller load corresponding to the first and last fatigue load spectra corresponding to the first specified proportion in the total time sorted from large to small or the last specified proportion in the total time sorted from small to large ; The roller parameters in the optimization parameters and the inner ring raceway parameters after deformation are calculated. The corresponding contact stress between the bearing roller and the inner ring raceway ; by With the goal of meeting the corresponding regulations, the roller surface repair amount in the roller parameters is adjusted to obtain the final parameters of the bearing.

2. The optimization method for wind power bearings according to claim 1, characterized in that: The inner ring raceway parameters after deformation include the diameter and surface shape of the inner ring raceway, which are obtained by theoretical calculation based on the slicing method.

3. The optimization method for wind power bearings according to claim 1, characterized in that: All calculations are based on the finite length line contact theory.

4. The optimization method for wind power bearings according to claim 1, characterized in that: The bearing model adopts a flexible simulation model.

5. The method for optimizing a wind power bearing according to claim 1, characterized in that: The steps of the optimization method are implemented using transmission simulation software.

6. The method for optimizing a wind power bearing according to claim 1, characterized in that: The deformation factors of the inner ring raceway include interference fit of the bearing and temperature rise during bearing operation.

7. The method for optimizing a wind power bearing according to claim 1, wherein: The said provisions account for 20%.

8. The method for optimizing a wind power bearing according to claim 1, characterized in that: The equivalent group number of the ultimate load spectrum ranges from 10 to 25.

9. The method for optimizing a wind power bearing according to claim 1, characterized in that: The equivalent group number of the fatigue load spectrum ranges from 100 to 500.

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