Planetary gear carrier cutting machining device capable of reducing machining errors and machining method

Abstract

The invention relates to the technical field of cutting machining, in particular to a planetary gear carrier cutting machining device and method capable of reducing machining errors, and the method comprises the steps that after rough turning machining is conducted on a planetary gear carrier in an RV speed reducer, the influence of the self-balance phenomenon of residual stress on stress relief is analyzed, and the machining error is reduced; establishing an influence relational expression of residual stress elimination; determining a dynamic switching strategy in the butterfly optimization algorithm based on the distribution of the feature points in the correlation curve of the three parameters; and determining optimal variables in different stages by using a butterfly optimization algorithm in combination with an influence relational expression of the internal stress self-balancing phenomenon of the planetary gear carrier structural member under the parameters on stress distribution, and performing subsequent processing on the obtained planetary gear carrier structural member to obtain the planetary gear carrier. The method aims to eliminate the residual stress of the planetary gear carrier subjected to rough turning, and the cutting machining error is reduced.

Description

Technical Field

[0001] This application relates to the technical field of cutting processing, and particularly relates to a planetary gear carrier cutting processing device and processing method for reducing processing errors. Background Art

[0002] The planetary gear carrier is one of the core parts of an RV (Rotary Vector) reducer, and together with the pin gear housing, cycloid gear, eccentric shaft, and planetary gears, etc., it constitutes an RV reducer. The planetary gear carrier includes a planetary carrier cover and a planetary carrier seat, and is one of the main components of the RV reducer in the gear mechanism. A reasonable structure of the planetary gear carrier should be light in weight, good in rigidity, wear-resistant, and easy to process and assemble. Usually, it needs to be processed in combination with processes such as rough turning, finish turning, and surface grinding.

[0003] During the cutting processing of the planetary gear carrier, residual stresses exist in the structural parts at different stages such as rough turning and finish turning, which easily lead to processing errors of the planetary gear carrier and form deformation problems. At present, methods for eliminating or reducing residual stresses include vibratory stress relief (VSR), thermal stress relief, cryogenic treatment, pulsed magnetic treatment, etc. Among them, vibratory stress relief has become an extremely commonly used method for eliminating residual stresses due to its low energy consumption, low cost, short cycle, high efficiency, and simple operation.

[0004] At present, when eliminating the residual stresses of the structural parts after rough turning using the VSR vibratory stress relief method, the three parameters of VSR are often found through an optimization method. However, the influence of the self-balancing phenomenon existing inside the structural parts after rough turning on the stress distribution during the process of vibration eliminating residual stresses is ignored, resulting in a poor effect of eliminating residual stresses and a large processing error. Summary of the Invention

[0005] In view of the above, it is necessary to provide a planetary gear carrier cutting processing device and processing method for reducing processing errors to solve the above problems.

[0006] The first aspect of this application provides a planetary gear carrier cutting processing method for reducing processing errors, and the method includes: Performing rough turning on the planetary carrier blank to obtain a planetary gear carrier structural part; Presetting monitoring points on the planetary gear carrier structural part; performing stress elimination simulation tests on the planetary gear carrier structural part based on each parameter of the vibratory stress relief method; determining the corresponding elimination effect based on the change in the stress values of each monitoring point before and after each simulation test, and performing curve fitting on the elimination effect and the corresponding parameter of each monitoring point during all simulation tests to obtain the correlation curve of each monitoring point for each parameter; Extract feature points based on the slope distribution characteristics of the corresponding points in each simulation test on the correlation curve of each parameter at each monitoring point; analyze the dispersion degree of the elimination effects corresponding to all simulation tests between two adjacent feature points on each correlation curve to determine the dynamic switching strategy of the butterfly optimization algorithm; extract the local range with two adjacent feature points on each correlation curve as endpoints, and obtain the first eigenvalue of each parameter in each local range according to the difference characteristics between the partial correlation curves of each local range at all monitoring points; determine the weight parameter according to the first eigenvalue corresponding to the position of each butterfly in each iteration of the butterfly optimization algorithm, replace the adjustment factor in the butterfly optimization algorithm, and combine the dynamic switching strategy to obtain the optimal VSR parameter, and obtain the planetary gear structural part with residual stress elimination. After benchmark surface trimming, semi-finishing turning, dynamic machining, precision grinding, planetary gear shaft hole end face grinding, and quality inspection of the planetary gear structural part with residual stress elimination, the machined planetary gear carrier is obtained.

[0007] Among them, the linear velocity of rough turning the planetary carrier blank is 80 - 120 m / min, and the axial feed is 0.2 - 0.3 mm / r.

[0008] Among them, determining the corresponding elimination effect based on the change of the stress value at each monitoring point before and after each simulation test is specifically as follows: Calculate the stress difference of each monitoring point before and after each simulation test, and take the ratio of the stress difference to the stress value after the test as the corresponding elimination effect.

[0009] Among them, the abscissa of the correlation curve is the parameter value adjusted in each simulation test; the ordinate is the elimination effect of each simulation test.

[0010] Among them, the process of extracting feature points is specifically as follows: Extract the slope of the corresponding points of all simulation tests on each correlation curve, and calculate the average slope; take the points with the slope greater than the average slope and the points corresponding to the initial simulation as feature points.

[0011] Among them, determining the dynamic switching strategy of the butterfly optimization algorithm is specifically as follows: Calculate the discrete eigenvalue of the elimination effects between two adjacent feature points on each correlation curve corresponding to each parameter; take the lower quartile of all the discrete eigenvalues on each correlation curve as the judgment threshold; take the local range with the discrete eigenvalue greater than the judgment threshold as the first type of interval for each parameter, and take the local range with the discrete eigenvalue less than or equal to the judgment threshold as the second type of interval for each parameter; Perform spatial partitioning using the first type of intervals of all parameters, determine the local space determined by the first type of intervals of all parameters as the area where local search needs to be performed, and use the remaining areas as the areas where global search needs to be performed.

[0012] Among them, the specific process of obtaining the first eigenvalue of each parameter in each local range is as follows: The specific influence relationship expressions corresponding to each parameter are as follows: ; in the formula, is the influence relationship expression corresponding to the a-th parameter; n is the number of monitoring points on the planetary gear carrier structural member; 、 are the expression of the correlation curve between the a-th parameter and the elimination effect at the i-th monitoring point and the j-th monitoring point respectively; Substitute the expressions corresponding to the partial correlation curves of each local range at all monitoring points into the influence relationship expression to obtain the first eigenvalue of each parameter in each local range.

[0013] Among them, the process of determining the weight parameter according to the first eigenvalue corresponding to the position where each butterfly is located during each iteration in the butterfly optimization algorithm is as follows: When there is 1 local range corresponding to each parameter at the position where each butterfly is located during each iteration, calculate the numerical proportion of the first eigenvalue of each parameter's local range in the maximum value of the first eigenvalues of all local ranges of each parameter; multiply the numerical proportions obtained for all parameters to obtain the weight parameter for each butterfly during each iteration; When there are more than 1 local ranges corresponding to each parameter at the position where each butterfly is located during each iteration, respectively take the average value of the first eigenvalues of all local ranges in each dimension corresponding to all three-dimensional local spaces; calculate the numerical proportion of the average value of the first eigenvalues of each parameter's local range in the maximum value of the first eigenvalues of all local ranges of each parameter; multiply the numerical proportions obtained for all parameters to obtain the weight parameter for each butterfly during each iteration.

[0014] Among them, the specific operation of semi-finishing turning is as follows: the linear velocity is increased to 150 - 180 m / min, the axial feed is 0.1 - 0.15 mm / r, and the cutting depth is 0.3 - 0.5 mm.

[0015] In a second aspect, an embodiment of the present application further provides a planetary gear carrier cutting processing device for reducing machining errors, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of the method described in any one of the above.

[0016] The present application has at least the following beneficial effects: The present application quantifies the influence relationship of the internal stress self - balance phenomenon on the stress distribution of the planetary gear structural parts under each parameter of the vibration aging treatment method, eliminates the influence of the self - structure of the planetary gear bracket on the residual stress distribution by means of multi - point cumulative averaging, and improves the stress elimination effect of the subsequent parameter optimization result on the planetary gear structural parts.

[0017] Furthermore, based on the change characteristics of the stress elimination effect within the local range where each parameter is located, a dynamic switching strategy in the optimization process is determined, which can adjust the search direction and strategy of the algorithm in real - time, avoid over - searching within a certain fixed range, reduce the risk of falling into local optimal solutions, and enhance the global search ability; an adaptive inertia weight is set by combining the first eigenvalues of each parameter in the local ranges of two adjacent characteristic points, making flexible adjustments according to the actual situation of parameter changes, and introducing more randomness to adjust the optimization strategy, so that the optimization process can better adapt to complex and dynamic environments, thereby effectively improving the optimization ability of the algorithm and further reducing the errors in the cutting process of the planetary gear bracket. Brief Description of the Drawings

[0018] Figure 1 It is a flowchart of the steps of a method for cutting a planetary gear bracket to reduce machining errors provided by an embodiment of the present application; Figure 2 It is a flowchart of the rough turning process provided by an embodiment of the present application; Figure 3 It is a schematic diagram of the distribution of monitoring points provided by an embodiment of the present application; Figure 4 It is a basic principle diagram of the VSR method provided by an embodiment of the present application. Detailed Embodiments

[0019] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary", "or", "for example" aims to present relevant concepts in a specific manner.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art belonging to the technical field of the present application. The terms used in the description of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0021] It should be noted that the terms "first" and "second" in this application and the accompanying drawings are used to distinguish similar objects, rather than to describe a specific order or sequence. The methods disclosed in the embodiments of this application or shown in the flowcharts include one or more steps for implementing the methods. Without departing from the scope of protection of this application, the execution order of multiple steps can be interchanged with each other, and some steps can also be deleted.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

[0023] The following specifically describes the specific solutions of a planetary gear carrier cutting processing device and a processing method for reducing processing errors provided by this application with reference to the accompanying drawings.

[0024] Please refer to Figure 1 , which shows the step flowchart of a planetary gear carrier cutting processing method for reducing processing errors provided by the embodiments of this application. The material used in this application is ductile iron QT450-10, including the following steps S10-S40: S10, rough turning: Rough turning is a key step in the preliminary shaping of the material, and the surplus is quickly removed through efficient cutting.

[0025] S101, clamping and positioning: Use a lathe, such as a double gantry vertical lathe or a heavy-duty CNC lathe, with the reference surface (such as the large end face or inner hole) of the planetary carrier blank as the clamping and positioning reference to ensure that the clamping force is evenly distributed and avoid subsequent processing errors caused by clamping deformation.

[0026] S102, set cutting parameters, including cutting speed and cutting depth. Since the hardness of QT450-10 in this application is about HB170-230, the linear speed is controlled at 80-120 m / min during rough turning to avoid the surface graphite from falling off or microcracks from occurring due to frictional high temperature; the cutting depth is set to a unilateral allowance of 3-5 mm, and the axial feed rate is 0.2-0.3 mm / r. The cutting depth should not be too large, otherwise the workpiece is prone to vibration during machine tool processing. In this embodiment, the linear speed for rough turning the planetary carrier blank is 80 m / min, and the axial feed rate is 0.2 mm / r; in other embodiments, the linear speed for rough turning the planetary carrier blank is 120 m / min, and the axial feed rate is 0.3 mm / r; in some other embodiments, the linear speed for rough turning the planetary carrier blank is 100 m / min, and the axial feed rate is 0.3 mm / r.

[0027] S103, Rough turning of the outer circle and end face: Turn the outer contour of the planet carrier to the design size, leaving a semi-finishing allowance of 0.5 - 1 mm, and machine the end face to a flatness of ≤ 0.1 mm; Rough boring of the inner hole: Rough bore the central hole of the planet carrier, leaving a bore diameter allowance of 1 - 1.5 mm, and control the cylindricity error of the inner hole within 0.05 mm.

[0028] S104, Stress relief treatment after rough turning. In this application, the vibration aging treatment method is used to eliminate the residual stress of the planet gear carrier structural member obtained after rough turning, and the optimal parameters during the vibration aging treatment are obtained in an optimized manner. The process flow chart of the rough turning process is as Figure 2 shown.

[0029] There is a self-balancing phenomenon of the residual stress in the planet gear carrier structural member obtained by rough turning, that is, the local stress release will cause the stress redistribution within the structural member. Specifically, when the residual stress in the local area of the structural member, such as tensile stress, is released by means such as machining, heat treatment or vibration aging, the elastic recovery and plastic deformation within the material will cause stress redistribution. For example, after the local tensile stress is released, the compressive stress or shear stress in the surrounding area will be transferred to the release area through elastic deformation to form a new equilibrium state.

[0030] S1041: Preset monitoring points on the planet gear carrier structural member.

[0031] After rough turning, select n uniformly distributed monitoring points around the center point on the planet gear carrier structural member. In this embodiment, the value of n is 8; among them, the schematic diagram of the distribution of the monitoring points is as Figure 3 shown, Figure 3 The large gray circle in the figure is the planet gear carrier structural member obtained by rough turning, and the black circles represent the monitoring points.

[0032] S1042: Conduct stress relief simulation tests on the planet gear carrier structural member based on each parameter of the vibration aging treatment method to eliminate residual stress.

[0033] Use the finite element analysis method to conduct stress relief simulation tests on the planet gear carrier structural member. For the three parameters of exciting force, exciting frequency and exciting time, keep one parameter changing within the allowable range each time, and the other two parameters remain unchanged. For each simulation test, use a stress detection instrument to obtain the stress Y0 and Y1 of each monitoring point before and after each residual stress elimination. The stress detection instrument includes but is not limited to the BN-SM100 static resistance strain gauge, JH-30 residual stress tester, and Zetec MIZ-22 eddy current instrument. In this embodiment, the Zetec MIZ-22 eddy current instrument is used; among them, the finite element analysis is a commonly used technology in the field of simulation tests, and the specific process will not be elaborated here.

[0034] S1043: Determine the corresponding elimination effect based on the change in stress values at each monitoring point before and after each simulation test. Curve fit the elimination effect and the corresponding parameters for each monitoring point during all simulation tests to obtain the correlation curve for each monitoring point with respect to each parameter.

[0035] Based on the simulation data of stress values and parameters from K simulation tests, determine the fitting results between each parameter and the elimination effect at each monitoring point through curve fitting to obtain the correlation curve represented in the form of a curve. In this embodiment, K is taken as 20; the method for obtaining the elimination effect is: calculate the stress difference at each monitoring point before and after each residual stress elimination, and take the ratio of the stress difference to the stress after elimination as the elimination effect of each monitoring point, that is, the ratio of the difference between Y1 and Y0 to Y1. The greater the difference, the more significant the elimination effect; in this embodiment, the least squares method is used for curve fitting, with the parameter value adjusted in each simulation test as the abscissa and the elimination effect of each simulation test as the ordinate. This application does not impose special restrictions on the curve fitting method, and the implementer can also choose polynomial fitting.

[0036] S1044: Obtain the influence relationship expression corresponding to each parameter through the difference characteristics between the correlation curves of all monitoring points under each parameter.

[0037] For any one parameter, represent the influence of the internal stress self - balance phenomenon of the structural member on the stress distribution through the differences between the correlation curves at all monitoring points, and obtain the influence relationship expression of the internal stress self - balance phenomenon of the structural member on the stress distribution under the a - th parameter , specifically: ; where n is the number of monitoring points on the planetary gear carrier structural member; 、 are the correlation curve expressions between the a - th parameter and the elimination effect at the i - th monitoring point and the j - th monitoring point respectively.

[0038] It should be noted that the influence of the structure of the planetary gear carrier itself on the residual stress distribution is eliminated by the method of multi - point cumulative averaging, improving the elimination effect of the subsequent parameter optimization result on the structural member. For example, after the stress at the inner wall corner of the planetary gear carrier is released, the stress in the adjacent area may transfer to the area far from the corner.

[0039] Obtain the influence relationship expressions of the internal stress self - balance phenomenon of the structural member on the stress distribution under three parameters respectively.

[0040] S1045: Extract feature points based on the slope distribution characteristics of the corresponding points in each simulation test in the correlation curve of each monitoring point with respect to each parameter.

[0041] The basic principle diagram of the VSR method is as Figure 4As shown in the figure, first, the host computer controls the signal generator to generate an excitation signal. After passing through the DC motor speed controller, this signal drives the DC speed-regulating motor fixed on the vibration platform. The operation of the motor causes the vibration platform to vibrate, and the vibration is transmitted through the elastic pad and acts on the structural member in the form of cyclic load. The structural member is fixed by the structural member fixture. After the excited vibration stress is superimposed on the internal residual stress, the combined stress in a certain direction will exceed the yield limit of the material and cause yield deformation, resulting in the relaxation and release of the residual stress, thereby eliminating or reducing the residual stress.

[0042] Specifically, there are mainly three parameters for the VSR method to eliminate residual stress: exciting force, exciting frequency, and exciting time. Among them, the exciting force refers to the external load applied by the vibration equipment to the structural member of the planetary gear carrier. When the exciting frequency is fixed, the greater the amplitude of the exciting force, the more exciting energy the grains obtain. However, too small an exciting force cannot cause plastic deformation of the workpiece, while too large an exciting force will damage the material and cause cracks. On the other hand, according to vibration theory, the excited vibration stress obtained by the component is the largest in the resonance state, and at the same time, the energy consumed by the vibration system is the least, and the effect of eliminating residual stress is the best. Therefore, the eliminating effect is the best when the exciting frequency is selected near the natural frequency. The exciting time refers to the duration of the reciprocating loading of the exciting load. If the time is too short, the residual internal stress cannot be reduced to the greatest extent, and if the time is too long, it will cause fatigue damage to the material.

[0043] First, taking the a-th parameter of each monitoring point as an example, obtain the slope of the corresponding point in the correlation curve for each simulation. The points on the correlation curve with a slope greater than the average slope and the starting point are all regarded as characteristic points. The greater the change in the eliminating effect between two adjacent characteristic points, it means that when the parameter value changes within a certain local range, the eliminating effect also shows an obvious change, indicating that adjusting the parameter value within this local range has a significant effect on eliminating residual stress. Then, within this local range, more attention should be paid to local optimization during the optimization process.

[0044] S1046: Analyze the dispersion degree of the corresponding eliminating effects of all simulation tests between two adjacent characteristic points on each correlation curve, and determine the dynamic switching strategy of the butterfly optimization algorithm.

[0045] Calculate the discrete eigenvalue of the elimination effect between adjacent two characteristic points on the correlation curve of the a-th parameter. The smaller the discrete eigenvalue, the less significant the change in the stress elimination effect corresponding to the adjusted parameter values within the adjacent two characteristic points. During the optimization process, the global optimization ability should be enhanced to quickly find the VSR parameters that have a good effect on eliminating the residual stress of the structural member. On the contrary, the larger the discrete eigenvalue, the greater the change in the stress elimination effect corresponding to the adjusted parameter values within the adjacent two characteristic points. During the optimization process, the local optimization ability should be enhanced to quickly find the VSR parameters that have a good effect on eliminating the residual stress of the structural member within a small range. In this embodiment, the discrete eigenvalue is calculated using the standard deviation; in different embodiments, the discrete eigenvalue can be calculated in forms such as distribution variance and coefficient of variation, and this application does not make special restrictions on this.

[0046] Obtain the lower quartiles of all the discrete eigenvalues on each correlation curve as the judgment thresholds respectively. Take the local range where the discrete eigenvalue is greater than the judgment threshold as the first type of interval of the a-th parameter, and take the local range where the discrete eigenvalue is less than or equal to the judgment threshold as the second type of interval of the a-th parameter.

[0047] In other embodiments, it is also possible to divide all the discrete eigenvalues on each correlation curve into two categories by binary classification, and take the local range corresponding to the category with the largest mean as the first type of interval of the a-th parameter; take the local range corresponding to the other category as the second type of interval of the a-th parameter. Among them, the calculation of quartiles and binary classification are all well-known techniques in the field of data processing, and the specific process will not be elaborated here.

[0048] When using the butterfly algorithm to find the optimal VSR parameters of the structural member, the optimization space is a three-dimensional space determined by the allowable ranges of the three parameters, and the three dimensions are exciting force, exciting frequency, and exciting time. Use the first type of intervals of the three parameters to perform space division in the three-dimensional space. Take the local space determined by the first type of intervals of the three parameters as the area that needs to be locally searched, and take the remaining area as the area that needs to be globally searched, thereby determining the dynamic switching strategy during the optimization process.

[0049] S1047: Extract the local range with adjacent two characteristic points on each correlation curve as endpoints, and substitute the partial correlation curves of each local range at all monitoring points into the influence relationship formula to obtain the first eigenvalue of each parameter in each local range.

[0050] The self-balancing phenomenon also has an obvious impact on the optimization of VSR parameters. That is, the smaller the influence of the self-balancing phenomenon within the parameter range on the stress distribution, the more uniform the internal stress distribution at different positions, and the three parameters of VSR are basically near the global optimal solution. At this time, attention should be paid to the ability of local optimization; conversely, the greater the influence of the self-balancing phenomenon within the parameter range on the stress distribution, the greater the difference in the internal stress distribution at different positions, and the release of the residual stress in the structural member is poor at this time, and the ability of global optimization should be enhanced.

[0051] Further, the abscissas of any two adjacent feature points corresponding to the a-th parameter of each monitoring point are used as the two endpoints of the local range. It should be understood that the local range corresponds to a part of the correlation curve on the correlation curves at different monitoring points; the expression of the correlation curve corresponding to the local range is substituted into the influence relationship of the self-balancing phenomenon of the internal stress of the structural member on the stress distribution under the a-th parameter , and the first eigenvalue corresponding to the local range of the two adjacent feature points is obtained. The larger the first eigenvalue, the more uneven the internal stress distribution of the structural member will be when setting the a-th parameter within this local range using the VSR technology to eliminate stress, and the ability of global optimization should be enhanced.

[0052] S1048. According to the first eigenvalue corresponding to the position of each butterfly at each iteration in the butterfly optimization algorithm, determine the weight parameter, replace the adjustment factor in the butterfly optimization algorithm, and combine the dynamic switching strategy to obtain the optimal VSR parameters, and obtain the planetary gear structural member with residual stress eliminated.

[0053] Specifically, an adaptive inertia weight is set based on the first eigenvalue of each parameter in the local range of two adjacent feature points, which increases the randomness of the adjustment strategy and effectively adjusts the optimization ability of the algorithm. The specific formula is: In the formula, is the weight parameter of the u-th butterfly at the t-th iteration, , , are respectively the first eigenvalues of the local ranges corresponding to the three parameter values at the position of the u-th butterfly at the t-th iteration, , , are respectively the maximum values of the first eigenvalues of all local ranges of the three parameters.

[0054] It should be noted that if the position of the u-th butterfly at the t-th iteration is located in the three-dimensional local space determined by multiple local ranges at the same time, the mean values of the first eigenvalues of all local ranges corresponding to each dimension of all three-dimensional local spaces are taken respectively.

[0055] As an example, the three-dimensional coordinates of the position of the \(u\)-th butterfly at the \(t\)-th iteration are , if is simultaneously located within the overlapping regions of three local three-dimensional spaces, and the ranges corresponding to the first local three-dimensional space in the corresponding dimensions of the \(a\)-th parameter, \(b\)-th parameter, and \(c\)-th parameter are respectively , , ; the ranges corresponding to the second local three-dimensional space in the corresponding dimensions of the \(a\)-th parameter, \(b\)-th parameter, and \(c\)-th parameter are respectively , , ; the ranges corresponding to the third local three-dimensional space in the corresponding dimensions of the \(a\)-th parameter, \(b\)-th parameter, and \(c\)-th parameter are respectively , , ; at this time, the average value of the first eigenvalues corresponding to the three local ranges of the \(a\)-th parameter in , and is taken as , the average value of the first eigenvalues corresponding to the three local ranges of the \(b\)-th parameter in , and is taken as , and the average value of the first eigenvalues corresponding to the three local ranges of the \(c\)-th parameter in , and is taken as .

[0056] Furthermore, the weight parameters obtained by each butterfly at each iteration are used to replace the adjustment factor in the original butterfly optimization algorithm, and the formula is as follows: In the formula, represents the adaptive inertia weight of the \(u\)-th butterfly at the \(t\)-th iteration; represents the current iteration number; represents the preset maximum iteration number; represents the weight parameter of the \(u\)-th butterfly at the \(t\)-th iteration; represents the logarithmic function with the natural constant as the base; represents as the base of the logarithmic function.

[0057] It should be understood that in the first half of the search, when, the butterfly individuals need to have a strong global search ability to ensure that the algorithm can perform extensive optimization in the search space. Therefore, the butterfly individuals need a large and stable weight for global optimization in the next iteration; in the second half of the search, When it comes to this, the butterfly individuals should possess strong local search capabilities to ensure better optimization of the population. Therefore, the butterfly individuals need a stable and relatively small weight to assist the population in deep exploration. An exponential weight is adopted to adaptively reduce the weight as the iteration progresses, thereby achieving the deep exploration of the population.

[0058] Furthermore, set the initial parameters of the butterfly optimization, including: the population size is taken as 50, the maximum number of iterations is taken as 500, the search space is a three-dimensional space determined by the allowable ranges of three parameters, the perception form is taken as 0.01, and the power exponent is taken as 0.1. Then, based on the dynamic switching strategy and the adaptive inertia weight in the determined optimization process, obtain the optimal solution, and output the three VSR parameters corresponding to the optimal solution. Among them, the butterfly optimization is a well-known technology, and the specific process will not be elaborated here.

[0059] Subsequently, based on the VSR parameters, generate digital signals by computer, and use a signal generator to eliminate the residual stress based on the digital signals, obtaining high-quality planetary gear carrier structural parts.

[0060] S20, Semi-finishing turning: Semi-finishing turning is a transitional process between rough turning and finishing, with the key being to improve dimensional consistency and further eliminate stress.

[0061] S201, Bench surface trimming: Re-trim the clamping bench surface to ensure that the flatness of the bench surface is ≤0.05 mm, providing a stable reference for subsequent processing.

[0062] S202, Cutting parameter adjustment: Linear speed increase: Increase to 150 - 180 m / min, use coated carbide inserts (such as CBN or ceramic coatings) to reduce the influence of cutting heat on the material. Feed adjustment: Axial feed is 0.1 - 0.15 mm / r, cutting depth is 0.3 - 0.5 mm to balance efficiency and surface quality. In this embodiment, the linear speed is increased to 150 m / min, the axial feed is 0.1 mm / r, and the cutting depth is 0.3 mm; in other embodiments, the linear speed is increased to 180 m / min, the axial feed is 0.15 mm / r, and the cutting depth is 0.5 mm; in some other embodiments, the linear speed is increased to 160 m / min, the axial feed is 0.12 mm / r, and the cutting depth is 0.5 mm.

[0063] S203, Semi-finishing turning processing: Outer circle and end face semi-finishing turning: The outer diameter size tolerance is controlled within ±0.1 mm, and the flatness of the end face is ≤0.05 mm. Inner hole semi-boring: The aperture allowance is left at 0.3 - 0.5 mm, the cylindricity error of the inner hole is ≤0.03 mm, and the surface roughness Ra is ≤3.2 μm.

[0064] S30, Machining center: The machining center undertakes the multi-process integrated machining of the complex structure of the planetary carrier, including the precision forming of the hole system, the mounting surface and the planetary gear shaft holes.

[0065] S301, Dynamic machining: Use a five-axis machining center, and clamp the workpiece once through a composite fixture to complete multiple processes such as milling, drilling, tapping, and heat treatment.

[0066] S40, Surface grinding: Surface grinding is the final process to ensure the high precision and surface quality of the end face of the planetary carrier and the key mating surfaces.

[0067] S401, Precision grinding: Use a high-precision surface grinder, fix the workpiece with an electromagnetic chuck, the grinding amount is 0.02 - 0.05 mm, the final flatness ≤ 0.005 mm, and the surface roughness Ra ≤ 0.4 μm.

[0068] S402, Grinding of the end face of the planetary gear shaft hole: Locally grind the end face of the planetary gear shaft hole to ensure that the axial assembly clearance ≤ 0.01 mm and reduce the axial runout during the operation of the RV reducer.

[0069] S403, Quality inspection: Coordinate measuring: Comprehensively inspect the hole positions, hole diameters, end face flatness, etc. to ensure compliance with the drawing requirements, such as the hole diameter tolerance H7 and the hole pitch ± 0.01 mm. Coordinate measuring can be realized by using a Zeiss coordinate measuring machine, such as the Zeiss Contura bridge-type coordinate measuring machine, to monitor the workpiece dimensions, shapes, positions, and various parallelisms and perpendicularities.

[0070] Thus, the planetary gear carrier is obtained.

[0071] Based on the same inventive concept as the above method, the embodiment of the present application also provides a planetary gear carrier cutting machining device for reducing machining errors, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned methods for reducing machining errors of the planetary gear carrier cutting machining method.

[0072] To sum up, the present application quantifies the influence of the internal stress self-balancing phenomenon of the planetary gear structural parts on the stress distribution under each parameter of the vibration aging treatment method, and eliminates the influence of the planetary gear carrier's own structure on the residual stress distribution by means of multi-point cumulative averaging, improving the stress elimination effect of the subsequent parameter optimization results on the planetary gear structural parts.

[0073] Furthermore, determining the dynamic switching strategy in the optimization process based on the variation characteristics of the stress relief effect within the local range where each parameter is located can adjust the search direction and strategy of the algorithm in real time, avoid over-searching within a certain fixed range, reduce the risk of falling into local optimal solutions, and enhance the global search ability. Setting an adaptive inertia weight by combining the first eigenvalue of the local ranges of each parameter at two adjacent characteristic points and making flexible adjustments according to the actual situation of parameter changes. By introducing more randomness to adjust the optimization strategy, the optimization process can better adapt to complex and dynamic environments, thereby effectively improving the optimization ability of the algorithm and further reducing the errors in the cutting process of the planetary gear carrier.

[0074] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than that disclosed in the description. Sometimes, there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. Each block in the block diagram and / or flowchart, as well as combinations of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0075] For those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the basic characteristics of the present application. Therefore, from any point of view, the above embodiments of the present application should be regarded as exemplary and non-restrictive. Modifying the technical solutions recorded in the foregoing embodiments, or equivalently replacing some of the technical features, does not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A cutting method for a planetary gear carrier to reduce machining errors, characterized in that, The method includes the following steps: Rough turning the blank of the planet carrier to obtain a planetary gear carrier structural part; Presetting monitoring points on the planetary gear carrier structural part; Based on each parameter of the vibration stress relief treatment method to eliminate residual stress, performing stress relief simulation tests on the planetary gear carrier structural part; Based on the change of the stress value at each monitoring point before and after each simulation test, determining the corresponding elimination effect, and performing curve fitting on the elimination effect and the corresponding parameter of each monitoring point during all simulation tests to obtain the correlation curve of each monitoring point for each parameter; Extracting characteristic points based on the slope distribution characteristics of the corresponding points of each simulation test in the correlation curve of each monitoring point for each parameter; Analyzing the dispersion degree of the elimination effects corresponding to all simulation tests between two adjacent characteristic points on each correlation curve to determine the dynamic switching strategy of the butterfly optimization algorithm; Extracting the local range with two adjacent characteristic points on each correlation curve as endpoints, and obtaining the first eigenvalue of each parameter in each local range according to the difference characteristics between the partial correlation curves of each local range among all monitoring points; Determining the weight parameter according to the first eigenvalue corresponding to the position where each butterfly is located during each iteration in the butterfly optimization algorithm, replacing the adjustment factor in the butterfly optimization algorithm, and combining the dynamic switching strategy to obtain the optimal VSR parameters, and obtaining a planetary gear structural part with residual stress eliminated; Performing reference plane trimming, semi-finishing turning, dynamic machining, precision grinding, end face grinding of the planetary gear shaft hole, and quality inspection on the planetary gear structural part with residual stress eliminated to obtain a machined planetary gear carrier.

2. The cutting method for a planetary gear carrier to reduce machining errors according to claim 1, characterized in that The linear velocity of rough turning the blank of the planet carrier is 80 - 120 m / min, and the axial feed rate is 0.2 - 0.3 mm / r.

3. A cutting method for a planetary gear carrier to reduce machining errors as described in claim 1, characterized in that, Based on the change of the stress value at each monitoring point before and after each simulation test, determining the corresponding elimination effect, specifically: Calculating the stress difference at each monitoring point before and after each simulation test, and taking the ratio of the stress difference to the stress value after the test as the corresponding elimination effect.

4. A cutting method for a planetary gear carrier to reduce machining errors according to claim 1, characterized in that, The abscissa of the correlation curve is the parameter value adjusted in each simulation test; the ordinate is the elimination effect of each simulation test.

5. A cutting method for a planetary gear carrier to reduce machining errors according to claim 1, characterized in that, The process of extracting characteristic points is specifically: Extracting the slopes of the corresponding points of all simulation tests on each correlation curve, and calculating the average slope; Taking the points with the slope greater than the average slope and the points corresponding to the initial simulation as characteristic points.

6. A cutting method for a planetary gear carrier to reduce machining errors according to claim 1, characterized in that, Determining the dynamic switching strategy of the butterfly optimization algorithm, specifically: Calculating the discrete eigenvalue of the elimination effects between two adjacent characteristic points on each correlation curve corresponding to each parameter; Taking the lower quartile of all the discrete eigenvalues on each correlation curve as the judgment threshold; Taking the local range with the discrete eigenvalue greater than the judgment threshold as the first type of interval for each parameter, and taking the local range with the discrete eigenvalue less than or equal to the judgment threshold as the second type of interval for each parameter; Using the first type of intervals of all parameters for space division, taking the local space determined by the first type of intervals of all parameters as the area where local search needs to be performed, and taking the remaining area as the area where global search needs to be performed.

7. A cutting method for a planetary gear carrier to reduce machining errors according to claim 1, characterized in that The specific process of obtaining the first eigenvalue of each parameter in each local range is as follows: The specific influence relationship corresponding to each parameter is as follows: ; In the formula, is the influence relationship corresponding to the a-th parameter; n is the number of monitoring points on the planetary gear carrier structure; and are the expression of the correlation curve between the a-th parameter and the elimination effect at the i-th monitoring point and the j-th monitoring point respectively; Substitute the expressions corresponding to the partial correlation curves of each local range at all monitoring points into the influence relation formula to obtain the first eigenvalue of each parameter in each local range.

8. A cutting method for a planetary gear carrier to reduce machining errors according to claim 1, characterized in that The process of determining the weight parameter according to the first eigenvalue corresponding to the position of each butterfly in each iteration of the butterfly optimization algorithm is specifically as follows: When there is 1 local range corresponding to each parameter at the position where each butterfly is located in each iteration, calculate the numerical proportion of the first eigenvalue of each parameter's local range in the maximum value of the first eigenvalues of all local ranges of each parameter; multiply the numerical proportions obtained for all parameters to obtain the weight parameter of each butterfly in each iteration. When there are more than 1 local ranges corresponding to each parameter at the position where each butterfly is located in each iteration, respectively take the mean value of the first eigenvalues of all local ranges in each dimension corresponding to all three-dimensional local spaces; calculate the numerical proportion of the mean value of the first eigenvalues of each parameter's local range in the maximum value of the first eigenvalues of all local ranges of each parameter; multiply the numerical proportions obtained for all parameters to obtain the weight parameter of each butterfly in each iteration.

9. A cutting method for a planetary gear carrier to reduce machining errors as described in claim 1, characterized in that, The specific operation of the semi-finishing turning is as follows: the linear velocity is increased to 150 - 180 m / min, the axial feed rate is 0.1 - 0.15 mm / r, and the cutting depth is 0.3 - 0.5 mm.

10. A planetary gear carrier cutting device for reducing machining errors, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 - 9.

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