Method for inverting dynamic meshing force of inner gear ring of gear box

Abstract

The invention provides a gear box inner gear ring dynamic meshing force inversion method. The method comprises the following steps that an inner gear ring-box body coupling system initial finite element model is established; calculating an initial unit load-surface strain influence matrix based on the initial finite element model; correcting the initial unit load-surface strain influence matrix based on the surface strain test data of the inner gear ring under various working conditions to obtain a corrected unit load-surface strain influence matrix; and calculating the meshing force of the planetary gear in the gearbox by using the corrected unit load-surface strain influence matrix. By adopting the technical scheme of the invention, accurate meshing force data can be obtained through inversion; whether the gearbox is overloaded or abnormally impacted or not can be monitored in real time, the load distribution uniformity of the planetary gear train is analyzed, and accurate load spectrum data support is provided for predictive maintenance and residual life evaluation of the gearbox.

Description

Technical Field

[0001] This invention relates to the field of gearbox condition monitoring and fault diagnosis technology, specifically to a method for inverting the dynamic meshing force of the gear ring inside a gearbox. Background Technology

[0002] The gearbox is the core transmission component of a wind turbine generator set, and its operating condition directly affects the reliability and lifespan of the entire unit. Planetary gear trains are widely used in wind turbine gearboxes due to their compact structure and high power density; however, the harsh operating environment and complex, variable loads of planetary gear trains, especially the uneven distribution of meshing forces (eccentric loading), can lead to pitting, tooth breakage, and other failures. Therefore, accurately obtaining the meshing force of the planetary gears is crucial for gearbox design verification, condition monitoring, lifespan prediction, and fault early warning.

[0003] In the current field of gearbox design and condition monitoring, the main methods for obtaining the meshing force of planetary gear trains include modeling and simulation based on dynamic software, load spectrum estimation based on wind speed statistics, and traditional experimental measurements on test benches. However, these methods all have significant limitations: the accuracy of dynamic simulation (such as multibody dynamics analysis) is highly dependent on the model accuracy, and its modeling process is complex and difficult to fully simulate actual assembly and boundary conditions such as bolt preload and contact stiffness, leading to deviations between the results and actual working conditions; the probabilistic statistical method based on wind speed is a macroscopic indirect estimation that cannot reflect the transient and dynamic load details inside the gearbox, especially the unbalanced load (eccentric load) phenomenon of the planetary gear train; traditional test bench measurements (such as using strain gauges or torque meters) can obtain direct data, but are costly. Furthermore, for complex working conditions such as offshore floating wind turbines under non-inertial frames, ground-based fixed tests cannot simulate the additional inertial load generated by the platform motion on gear meshing, resulting in "significant differences between ground test results and wind field measured results". Furthermore, indirect analysis methods based on vibration signals suffer from low accuracy and reliability in load inversion due to their complex signal transmission paths, insensitivity to specific meshing forces, and susceptibility to interference from other vibration sources and variable load conditions. Therefore, there is an urgent need for a method that can directly, accurately, and in real-time monitor the meshing forces of planetary gears inside a gearbox. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a method for inverting the dynamic meshing force of the gear ring inside a gearbox, in order to solve the technical problem of low accuracy and reliability in obtaining the meshing force of planetary gear trains using existing technologies.

[0005] The technical solution adopted in this invention is as follows: Firstly, a method for inverting the dynamic meshing force of the gear ring inside a gearbox is provided, including the following steps: Establish the initial finite element model of the internal gear ring-box coupling system; Calculate the initial unit load-surface strain influence matrix based on the initial finite element model; Based on the test data of surface strain of internal gear ring under various working conditions, the initial unit load-surface strain influence matrix is ​​corrected to obtain the corrected unit load-surface strain influence matrix. The modified unit load-surface strain influence matrix was used to calculate the meshing force of the planetary gears inside the gearbox.

[0006] Furthermore, an initial finite element model of the internal gear ring-gear housing coupling system is established, including: setting condensation points on the teeth of the internal gear ring according to its structural characteristics, and using software to establish a finite element condensation model of the gearbox.

[0007] Furthermore, beam elements are used to simplify the bolt modeling.

[0008] Furthermore, when setting a convergence point on the teeth of the internal gear ring, a convergence point is defined in the central region of each tooth of the internal gear ring through coupling constraints; at the convergence point, a local coordinate system of meshing force is established, and the three coordinate axes of the local coordinate system are set in the following manner: one axis is perpendicular to the tooth surface, one axis is along the tangent direction of the gear circumference, and the other axis is along the axial direction of the gear.

[0009] Furthermore, the initial unit load-surface strain influence matrix is ​​calculated based on the initial finite element model, including: A unit load is applied sequentially to the three directions of the local coordinate system defined at each tooth convergence point; after each application of the unit load, the measured strain response values ​​at the measuring points on the outer surface of the internal gear ring are extracted and recorded. By iterating through all directions of all gear teeth, the strain response data generated by each unit load are arranged in order and assembled to obtain the initial unit load-surface strain influence matrix.

[0010] Furthermore, the measured strain response values ​​at measuring points on the outer surface of the internal gear ring are extracted and recorded using a grating fiber optic strain monitoring system; the grating fiber optic strain monitoring system includes: A grating fiber optic sensor is used to acquire strain signals. Along the middle of the outer surface of the internal gear ring, grating fiber optic sensors with an integer multiple of planetary gears are evenly arranged circumferentially as measuring points. The data acquisition subsystem is used to acquire the center wavelength offset of each fiber optic sensor in real time using a high-frequency fiber optic demodulator.

[0011] Furthermore, the initial unit load-surface strain influence matrix is ​​corrected based on surface strain test data of the internal gear ring under various working conditions, including: The key parameters to be corrected are obtained by selecting the parameters to be corrected through sensitivity analysis; The key parameters to be corrected are solved through iterative optimization.

[0012] Furthermore, the parameters to be corrected include the contact stiffness of the connecting bolts, the elastic modulus of the material, and the number of meshes; the key parameter to be corrected is the contact stiffness of the connecting bolts. The iterative optimization solution method used is the sequential quadratic programming method.

[0013] Secondly, an electronic device is provided, comprising: One or more processors; Storage device for storing one or more programs; When one or more programs are executed by one or more processors, the one or more processors implement the dynamic meshing force inversion method for the gearbox internal gear ring described in the first aspect.

[0014] Fourthly, a computer program product is provided, including a computer program / instruction, which, when executed by a processor, implements the steps of the dynamic meshing force inversion method for the gearbox internal gear ring described in the first aspect.

[0015] As can be seen from the above technical solution, the beneficial technical effects of the present invention are as follows: The inversion can obtain accurate meshing force data; it can monitor in real time whether the gearbox is overloaded or subjected to abnormal impact, analyze the load distribution uniformity of the planetary gear train, and provide accurate load spectrum data support for predictive maintenance and remaining life assessment of the gearbox. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 This is a schematic diagram of the dynamic meshing force inversion method for the gear ring inside the gearbox in an embodiment of the present invention; Figure 2 This is a schematic diagram of the condensation point of the internal gear ring in the finite element model of the internal gear ring-box coupling system in an embodiment of the present invention. Figure 3 This is a schematic diagram of the grating fiber strain monitoring system in an embodiment of the present invention; Figure 4 This is a schematic diagram showing the location of strain measurement points for extracting and calculating the response in an embodiment of the present invention; Figure 5 This is a comparison chart of the actual value and the inverted value in an embodiment of the present invention. Detailed Implementation

[0018] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0019] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by those skilled in the art to which this invention pertains.

[0020] Example This embodiment provides a method for inverting the dynamic meshing force of the gear ring inside a gearbox, including the following steps: Step 1: Establish the initial finite element model of the internal gear ring-box coupling system Based on the structural characteristics of the internal gear ring, condensation points are set on the teeth of the internal gear ring. A finite element condensation model of the gearbox is established using software (such as ANSYS or ABAQUS). This finite element model will be corrected in subsequent steps. Therefore, the finite element model of the initial internal gear ring-gearbox coupling system is obtained in this step.

[0021] During the modeling process, it is necessary to consider the impact of the difference in preload and stiffness of the box bolts on the calculation results. Since there are a large number of bolts and the global structural stiffness analysis is performed in this embodiment, the bolt modeling can be simplified by using beam elements. This approach can not only realistically reflect the boundary conditions and overall stiffness of the structure, but also has a greater advantage in computational efficiency than modeling the bolts as solids.

[0022] When setting contraction points on the teeth of an internal gear ring, a contraction point is defined in the central region of each tooth of the internal gear ring through coupling constraints, such as... Figure 2 As shown, the coupling constraint is specifically as follows: the center point of each tooth is selected as the master control point, and the corresponding two tooth surfaces are the controlled surfaces, and coupling constraints are applied. Simultaneously, at the convergence point, a local coordinate system for the meshing force is established. The three coordinate axes of this system are set as follows: one axis is perpendicular to the tooth surface, corresponding to the normal component of the meshing force; one axis is along the tangential direction of the gear circumference, corresponding to the tangential component of the meshing force; and the other axis is along the axial direction of the gear, corresponding to the axial component of the meshing force. This step lays the foundation for the subsequent accurate separation and identification of the three-dimensional meshing force.

[0023] Step 2: Calculate the initial unit load-surface strain influence matrix based on the initial finite element model. The inventors of this application discovered through research that there is a significant and concentrated strain change on the outer surface of the internal gear ring near the meshing point of the planetary gears. This strain signal has a good linear relationship with the applied load and has a high signal-to-noise ratio. In order to record the effect of strain, a grating fiber optic sensor is selected in this embodiment. Attaching it to the outer surface of the internal gear ring can effectively capture the strain signal.

[0024] Based on the above research results, this embodiment constructs a grating fiber optic strain monitoring system for acquiring strain data of the internal gear ring surface, such as... Figure 3 As shown, the monitoring system includes: a grating fiber optic sensor, a data acquisition subsystem, and a data processing and inversion subsystem, wherein: Grating fiber optic sensors offer advantages such as resistance to electromagnetic interference and good long-term stability, making them suitable for various complex working conditions. The specific arrangement of the grating fiber optic sensors is as follows: Grating fiber optic sensors are evenly arranged at circumferential intervals equal to the number of planetary gears along the center of the outer surface of the internal gear ring. Preferably, the number of fiber optic strain sensor measuring points is twice the number of planetary gears, and the positions are arranged as follows... Figure 4 As shown.

[0025] Data acquisition subsystem: A high-frequency fiber optic demodulator is used to acquire the center wavelength offset (i.e. strain value) of each fiber optic sensor in real time.

[0026] Data processing and inversion subsystem: Embedded industrial computer with built-in load inversion calculation software.

[0027] In this step, based on the initial finite element model obtained in step one, a static analysis under unit load is performed: a 1kN unit load is applied sequentially in three directions of the local coordinate system defined at each tooth convergence point. After each application of the unit load, the strain response value at the measuring point of the grating fiber strain sensor on the outer surface of the internal gear ring is extracted and recorded using a grating fiber strain monitoring system. By traversing all directions of all teeth, the strain response data generated by each unit load are arranged sequentially, and finally assembled into a complete unit load strain influence matrix, i.e., the initial unit load strain influence matrix. : in, This represents the number of sensor measurement points. The number of external loads; the row vector represents a single measuring point. The strain components along the same direction under independent unit loads; the column vector is... The strain components at each measuring point under a unit load in one direction are represented by this matrix. This matrix establishes a linear mapping relationship between the unit meshing force and the strain on the outer surface of the internal gear ring.

[0028] Step 3: Based on the surface strain test data of the internal gear ring under various working conditions, the initial unit load-surface strain influence matrix is ​​corrected to obtain the corrected unit load-surface strain influence matrix. The core objective of this step is to utilize the real strain data acquired by the grating fiber optic strain monitoring system under rated operating conditions. The initial unit load-surface strain influence matrix established in the preceding steps is then calibrated. This process systematically corrects model errors caused by model simplification, material parameter uncertainties, boundary condition assumptions, and inaccurate bolt stiffness simulation, thereby significantly improving the prediction accuracy of the finite element model and laying a reliable foundation for subsequent high-precision load inversion. The correction process includes: Parameter Selection and Sensitivity Analysis: Parameters with significant impact on structural response and high uncertainty were selected as parameters to be corrected. These parameters included the contact stiffness of the connecting bolts, the elastic modulus of the material, and the number of meshes (in this embodiment, the number of meshes in the ABAQUS finite element model). Through sensitivity analysis, this study employed the Design of Experiments (DOE) method to systematically change the preset parameters to be corrected and observe their impact on the calculated strain. This allowed for the selection of key parameters to be corrected, identifying those with the greatest impact on the strain at each measuring point, and prioritizing their correction. Experiments revealed that the contact stiffness of the connecting bolts was one of the most sensitive parameters; therefore, it was prioritized for correction to improve optimization efficiency.

[0029] Optimization Solution: Within a reasonable range of parameter variation, adjust the values ​​of the parameters to be corrected until the calculated response strain approximates the measured response strain; this indicates that the optimal parameter combination has been obtained. In specific implementations, the iterative optimization solution process can be implemented using mathematical calculation software (such as MATLAB's optimization toolbox). This process uses a weighted least squares objective function as the optimization objective: in, For the first The measured strain values ​​at each measuring point No. Finite element analysis of strain values ​​at each measuring point For the first The weighting factor for each measurement point data point; for this application, considering that the data quality monitored by each grating fiber optic sensor is comparable, and that the strain data quality is good with a low signal-to-noise ratio, therefore, the following weighting factor is used: The value is 1.

[0030] With the parameter vector to be corrected (Connecting bolt contact stiffness) is a design variable. Within the set physical constraints of the parameters, an optimization algorithm (such as sequential quadratic programming) is used for iterative processing until a preset convergence threshold is met. Threshold Based on engineering accuracy requirements and numerical experiments, the threshold value in this embodiment is determined comprehensively. Set to 1.0×10 −6The optimization process is considered to have converged when the relative change in the objective function value is less than this threshold for three consecutive iterations. This threshold ensures that the average relative error between the calculated strain and the experimental strain of the modified finite element model under verification conditions is less than 0.5%, while avoiding unnecessary consumption of computational resources.

[0031] Model Validation and Update: The optimized parameters are updated into the initial finite element model to form a modified finite element model. Based on the modified finite element model, the strain of each tooth under each unit load (i.e., covering all load component directions during the entire model operation) under its circumferential force, radial force, and axial force is recalculated, and then compared with the initial unit load strain influence matrix. The assembly process is as follows: the column vector represents the strain of each measuring point extracted by ABAQUS under a unit load in the same direction; the row vector represents the strain of a single measuring point extracted by ABAQUS under a unit load in each direction. The corrected unit load-surface strain influence matrix [A] is obtained as follows: The corrected matrix here has the same dimensions and meaning as the uncorrected matrix above. Both are derived from the strain of the measured points through ABAQUS finite element calculation. However, the corrected matrix is ​​derived from the finite element calculation of the previous corrected model. The strain of the matrix is ​​closer to the measured strain data, which improves the inversion accuracy.

[0032] In some embodiments, the strain under rated conditions can be calculated using the modified finite element model, and then compared with the experimental data monitored by the grating fiber strain monitoring system under rated conditions to verify the correction effect. Simultaneously, strain under other conditions can also be calculated and compared with the experimental data monitored by the grating fiber strain monitoring system under those conditions to verify whether the modified unit load-surface strain influence matrix has universality; the verification results are as follows: Figure 5 As shown in the figure, the comparison results of the circumferential force among the three component forces can be seen. It can be seen that the inversion method of this study has high accuracy, which indicates that the study adopted the correct inversion theory and reasonable model correction and optimization, effectively controlling the deviation between simulation and measurement, and has the conditions for application in engineering practice.

[0033] The corrected unit load-surface strain influence matrix obtained in this embodiment can be used to invert the dynamic meshing force and load of the gear ring inside the gearbox. Specifically, the modified unit load-surface strain influence matrix is ​​used to calculate the meshing force of the planetary gears inside the gearbox, as follows: Once the corrected unit load-surface strain influence matrix [A] is determined, the measured strain data at the measurement points can be used as input to achieve structural load inversion. In this embodiment, the inverted gear meshing force load is expressed as: In practical engineering applications, the accurate meshing force data obtained through inversion using the above method can be used to: 1) monitor in real time whether the gearbox is overloaded or subjected to abnormal impact; 2) analyze the load distribution uniformity of the planetary gear train (eccentric load analysis), such as calculating the load sharing coefficient and assessing the health status of the system; 3) provide accurate load spectrum data support for predictive maintenance and remaining life assessment of the gearbox.

[0034] In some embodiments, an electronic device is provided, including: one or more processors; a storage device for storing one or more programs; and when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned method for inverting the dynamic meshing force of the gearbox internal gear ring.

[0035] In other embodiments, a computer program product is provided, including a computer program / instructions that, when executed by a processor, implement the steps of the aforementioned method for inverting the dynamic meshing force of the gear ring gear in a gearbox.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for inverting the dynamic meshing force of an internal gear ring in a gearbox, characterized in that, Includes the following steps: Establish the initial finite element model of the internal gear ring-box coupling system; Calculate the initial unit load-surface strain influence matrix based on the initial finite element model; Based on the test data of surface strain of internal gear ring under various working conditions, the initial unit load-surface strain influence matrix is ​​corrected to obtain the corrected unit load-surface strain influence matrix. The modified unit load-surface strain influence matrix was used to calculate the meshing force of the planetary gears inside the gearbox.

2. The method for inverting the dynamic meshing force of the gear ring gear in a gearbox according to claim 1, characterized in that, Establishing an initial finite element model of the internal gear ring-gear housing coupled system includes: setting condensation points on the teeth of the internal gear ring based on its structural characteristics, and using software to establish a finite element condensation model of the gearbox.

3. The method for inverting the dynamic meshing force of the gear ring gear in a gearbox according to claim 2, characterized in that, The bolts are modeled using beam elements to simplify the process.

4. The method for inverting the dynamic meshing force of the gear ring gear in a gearbox according to claim 2, characterized in that, When setting a convergence point on the teeth of the internal gear ring, a convergence point is defined in the central region of each tooth of the internal gear ring through coupling constraints; at the convergence point, a local coordinate system of meshing force is established, and the three coordinate axes of the local coordinate system are set in the following manner: one axis is perpendicular to the tooth surface, one axis is along the tangent direction of the gear circumference, and the other axis is along the axial direction of the gear.

5. The method for inverting the dynamic meshing force of the gear ring gear in a gearbox according to claim 4, characterized in that, The initial unit load-surface strain influence matrix is ​​calculated based on the initial finite element model, including: A unit load is applied sequentially to the three directions of the local coordinate system defined at each tooth convergence point; after each application of the unit load, the measured strain response values ​​at the measuring points on the outer surface of the internal gear ring are extracted and recorded. By iterating through all directions of all gear teeth, the strain response data generated by each unit load are arranged in order and assembled to obtain the initial unit load-surface strain influence matrix.

6. The method for inverting the dynamic meshing force of the gear ring gear in a gearbox according to claim 5, characterized in that, The strain response values ​​at the measuring points on the outer surface of the internal gear ring were extracted and recorded using a grating fiber strain monitoring system. The grating fiber strain monitoring system includes: A grating fiber optic sensor is used to acquire strain signals. Along the middle of the outer surface of the internal gear ring, grating fiber optic sensors with an integer multiple of planetary gears are evenly arranged circumferentially as measuring points. The data acquisition subsystem is used to acquire the center wavelength offset of each fiber optic sensor in real time using a high-frequency fiber optic demodulator.

7. The method for inverting the dynamic meshing force of the gear ring gear in a gearbox according to claim 1, characterized in that, The initial unit load-surface strain influence matrix was corrected based on surface strain test data of the internal gear ring under various working conditions, including: The key parameters to be corrected are obtained by selecting the parameters to be corrected through sensitivity analysis. The key parameters to be corrected are solved through iterative optimization.

8. The method for inverting the dynamic meshing force of the gear ring gear in a gearbox according to claim 7, characterized in that, The parameters to be corrected include the contact stiffness of the connecting bolts, the elastic modulus of the material, and the number of meshes; the key parameter to be corrected is the contact stiffness of the connecting bolts. The iterative optimization solution method used is the sequential quadratic programming method.

9. An electronic device, characterized in that, include: One or more processors; Storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the gearbox internal gear ring dynamic meshing force inversion method according to any one of claims 1-8.

10. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the gearbox internal gear ring dynamic meshing force inversion method according to any one of claims 1-8.

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