A method for adjusting the helix angle of spline key teeth

Abstract

The present invention discloses a method for adjusting the helical angle of a spline key tooth, and relates to the technical field of spline key tooth detection. The method for adjusting the helical angle of a spline key tooth comprises the following steps: obtaining stress data, initial path planning, dynamic path optimization, and adjustment effect evaluation. The present invention introduces stress data obtained by stress detection, and then performs initial path planning based on the tooth surface error evaluation coefficient obtained based on the tooth surface data, and then obtains the processing error evaluation coefficient based on the processing data and stress data to determine whether to perform dynamic path optimization, and finally obtains the adjustment effect evaluation coefficient through the test data to determine whether to re-plan the path, thereby achieving the effect of improving the accuracy of processing path optimization during the helical angle modification process, and solves the problem of low accuracy of processing path optimization during the helical angle modification process in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of spline key tooth detection, and in particular to a helical angle modification and adjustment method for a spline key tooth. Background Art

[0002] As a key component in the aviation transmission system, the performance of the involute spline directly affects the operation of the entire system. During the flight, it will experience various complex environmental conditions, such as high speed, high torque and high vibration. These environmental factors will cause the material properties of the spline to change, aggravating the wear and fatigue damage of the tooth surface. In addition, due to factors such as manufacturing accuracy, assembly errors and deformation during the working process, higher requirements are placed on the performance, life and stability of aviation involute splines. Involute splines have the important task of transmitting power in aviation transmission systems. By modifying the helix angle of the key teeth of the involute spline, not only can the contact stress and wear of the spline pair be reduced, but also the centering stability of the spline pair can be improved, thereby reducing the probability of failure and ensuring flight safety.

[0003] The existing spline key tooth helix angle modification is mainly compensated for manufacturing errors by adjusting processing parameters or manual modification. Common methods include modifying tool trajectory, adjusting fixture angle or using special grinding tools for local modification. The application of CNC machining equipment has improved the accuracy of helix angle modification, but there are still some problems: for example, the modification process is complicated and requires repeated measurement and adjustment; for mass production, the efficiency is low and the cost is high; manual modification is easily affected by the operator's experience, resulting in poor consistency. In addition, traditional methods are not adaptable enough to complex helix angle error distributions, making it difficult to fully optimize the meshing performance of the tooth surface. Therefore, further improving the modification efficiency and accuracy has become the direction of technical improvement.

[0004] For example, the invention patent with announcement number: CN110514737B announces a maintenance system for gear flaw detection, which includes: a base, a chassis and a flaw detector. The chassis is fixedly installed on the upper end of the base, a PLC (Programmable Logic Controller) controller is fixedly installed on one side of the outer wall of the base, a box door is hingedly installed on one side of the outer wall of the chassis, a No. 1 motor and a bearing seat are fixedly installed on one side of the bottom end of the chassis, and the bearing seats are provided with two groups, threaded rods are rotatably installed between the bearing seats, a threaded slide is installed on the outer thread of the threaded rod, and a support rod is fixedly installed on the upper end of the threaded slide through a carrier plate.

[0005] For example, the invention patent with announcement number: CN108181318B announces a method for processing a gear with asymmetric tooth profile modification, including: 1) designing the number of teeth, tooth width, tooth top circle diameter, tooth root circle diameter of the measured gear and the requirements of the installation center distance of the measured gear; 2) measuring b and △X according to the tooth profile modification requirements of the measured gear, and calculating the helix angle modification angle △β according to the formula tan△β=△X / b, wherein b is the tooth width size, unit is mm; △X is the modification amount size, unit is mm; △β is the helix angle modification angle, unit is °; 3) reverse grinding the measured gear according to the helix angle modification angle △β in step 2).

[0006] However, in the process of implementing the technical solution of the invention in the embodiments of the present application, it was found that the above technology has at least the following technical problems: in the prior art, the existing detection equipment has limitations in the measurement accuracy, speed and degree of full automation of the helix angle and tooth profile error, and the real-time detection and feedback control are still imperfect, which affects the shaping effect, and there is a problem of low accuracy in the optimization of the processing path during the helix angle shaping process. Summary of the invention

[0007] The embodiment of the present application solves the problem of low accuracy of machining path optimization during the helix angle modification process in the prior art by providing a method for adjusting the helix angle modification of spline key teeth, thereby improving the accuracy of machining path optimization during the helix angle modification process.

[0008] The embodiment of the present application provides a method for adjusting the helical angle of a spline key tooth, comprising the following steps: introducing stress detection before the helical angle modification to monitor the stress condition of the spline key tooth during the whole process of the helical angle modification to obtain corresponding stress data, wherein the stress detection includes inputting basic expressions for spline parametric modeling and helical angle parametric correction, generating a helical spline pair model using UG software, meshing the complex structure model imported into Hypermesh software after segmentation, and performing finite element simulation calculation on the divided mesh units using Abaqus software, and comparing and analyzing the contact stress magnitudes of the spline tooth surfaces with different helical angles; acquiring tooth surface data in real time through a measuring device, and based on The tooth surface error evaluation coefficient obtained from the tooth surface data is used for initial path planning, and the tooth surface error evaluation coefficient is used to quantify the degree of deviation between the spline key tooth and the designed theoretical profile; during the helix angle modification adjustment process, the processing data is obtained by detecting the sensor, and the processing error evaluation coefficient is obtained based on the processing data and stress data to determine whether to perform dynamic path optimization, and the processing error evaluation coefficient is used to quantify the accumulated errors generated during the processing process; after the helix angle modification adjustment process, the test data is obtained through the testing instrument, and the adjustment effect evaluation coefficient is obtained based on the test data to determine whether to re-plan the path, and the adjustment effect evaluation coefficient is used to quantify the effect of the helix angle modification adjustment of the spline key tooth.

[0009] Furthermore, the stress data includes contact stress and contact stress reduction rate; the tooth surface data includes tooth profile deviation value, tooth height error, tooth direction error and surface roughness; the processing data includes cutting force, spindle speed, tool wear and tool temperature; the test data includes backlash, transmission error and dynamic contact area.

[0010] Furthermore, the specific process of performing initial path planning based on the tooth surface error evaluation coefficient obtained based on the tooth surface data is as follows:

[0011] According to the helix angle structure of the spline key teeth, the modification area is divided and each modification area is recorded as a to-be-modified area, and the to-be-modified areas are numbered; the minimum limit value of roughness is obtained from a preset database, and the tooth surface data and the minimum limit value of roughness are processed to obtain a tooth surface error evaluation coefficient; the specific restriction expression of the tooth surface error evaluation coefficient is as follows:

[0012] ;

[0013] In the formula, n represents the number of the area to be modified. , Indicates the total number of areas to be reshaped. Indicates the tooth profile deviation value of the nth area to be modified, represents the tooth height error of the nth area to be modified, represents the tooth direction error of the nth area to be modified, represents the surface roughness of the nth area to be modified, Indicates the minimum roughness limit, Represents the tooth surface error evaluation coefficient of the nth area to be modified.

[0014] Furthermore, the specific steps of the initial path planning are as follows:

[0015] S1, compare the tooth surface error evaluation coefficient with the tooth surface evaluation interval to determine the processing technology, and the processing technology includes rough processing, semi-finishing and finishing; S2, determine the path curve according to the gear geometry parameters of the spline key teeth, and the path curve includes an axial path, a radial path and a compound path; S3, determine the cutting parameters according to the processing technology, and the cutting parameters include cutting depth, feed speed and cutting speed; S4, generate an initial processing path in the CAM software, and the initial processing path covers the area to be modified.

[0016] Furthermore, the specific process of comparing the tooth surface error evaluation coefficient with the tooth surface evaluation interval to determine the processing technology is as follows:

[0017] A tooth surface evaluation interval is obtained from a preset database, and the tooth surface evaluation interval includes a first tooth surface evaluation interval, a second tooth surface evaluation interval and a third tooth surface evaluation interval; if the tooth surface error evaluation coefficient belongs to the first tooth surface evaluation interval, the processing technology of the area to be modified is rough machining; if the tooth surface error evaluation coefficient belongs to the second tooth surface evaluation interval, the processing technology of the area to be modified is semi-finishing; if the tooth surface error evaluation coefficient belongs to the third tooth surface evaluation interval, the processing technology of the area to be modified is finishing.

[0018] Furthermore, the specific process of obtaining the machining error evaluation coefficient is as follows:

[0019] Reference machining data and reference stress data are obtained from a preset database, wherein the reference machining data include a minimum cutting force, a maximum cutting force, a minimum spindle speed, a maximum spindle speed, a critical value of tool wear, and a tool temperature limit, and the reference stress data include a minimum contact stress, a maximum contact stress, a minimum contact stress reduction rate, and a maximum contact stress reduction rate; a machining evaluation weight factor is obtained from a preset database, wherein the machining evaluation weight factor includes a machining weight factor and a stress weight factor; a machining evaluation index is obtained according to the reference machining data corresponding to the machining data, wherein the machining evaluation index includes a cutting force index, a spindle speed index, a tool wear index, and a tool temperature index; a stress evaluation index is obtained according to the stress data and the corresponding reference stress data, wherein the stress evaluation index includes a contact stress index and a contact stress reduction rate index; a machining error evaluation coefficient is obtained based on the machining evaluation index, the stress evaluation index, and the machining evaluation weight factor.

[0020] Furthermore, the specific process of determining whether to perform dynamic path optimization is as follows:

[0021] Obtain an optimization threshold from a preset database, where the optimization threshold is used to determine whether to perform dynamic path optimization; determine the relationship between the machining error evaluation coefficient and the optimization threshold:

[0022] If the machining error evaluation coefficient is not less than the optimization threshold, path dynamic optimization is not performed; if the machining error evaluation coefficient is less than the optimization threshold, path dynamic optimization is performed; the path dynamic optimization includes shortening the non-cutting path and dynamically adjusting the cutting parameters.

[0023] Furthermore, the specific process of obtaining the adjustment effect evaluation coefficient is as follows:

[0024] The minimum value of the dynamic contact area is obtained from the preset database, and the dynamic contact area is compared with the minimum value of the dynamic contact area: if the dynamic contact area is not less than the minimum value of the dynamic contact area, the adjustment effect evaluation coefficient is recorded as 0; if the dynamic contact area is less than the minimum value of the dynamic contact area, the results of processing the hysteresis, transmission error and dynamic contact area respectively are summed to obtain the adjustment effect evaluation coefficient.

[0025] Furthermore, the specific process of determining whether to re-plan the path is as follows:

[0026] A planning threshold is obtained from a preset database, and the planning threshold is used to determine whether to perform path replanning; the relationship between the adjustment effect evaluation coefficient and the planning threshold is determined: if the adjustment effect evaluation coefficient is not less than the planning threshold, path replanning is not performed; if the adjustment effect evaluation coefficient is less than the planning threshold, path replanning is performed, and when the monitored adjustment effect evaluation coefficient is not less than the planning threshold, path replanning is terminated, otherwise path replanning continues.

[0027] Furthermore, the stress data is obtained as follows:

[0028] A helical spline model is drawn by using three-dimensional modeling software, and the helical spline model is used to simulate the helix angle of the spline key teeth; the helical spline model is imported into the meshing software to generate a hexahedral mesh, and then the finite element software is called to simulate and calculate the tooth surface contact stress and contact stress reduction rate under torque loading.

[0029] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0030] 1. The initial path planning is performed through the obtained tooth surface error evaluation coefficient, and then the processing error evaluation coefficient is obtained based on the processing data and stress data to determine whether to perform dynamic path optimization. Finally, the adjustment effect evaluation coefficient is obtained through the test data to determine whether to re-plan the path, thereby providing a more reasonable processing path for helix angle modification, thereby improving the accuracy of processing path optimization during helix angle modification, and effectively solving the problem of low accuracy of processing path optimization during helix angle modification in the prior art.

[0031] 2. The shaping area is divided according to the helix angle structure of the spline key teeth and each shaping area is recorded as the area to be modified. At the same time, the areas to be modified are numbered, and then the minimum limit of roughness is obtained from the preset database. The tooth surface data and the minimum limit of roughness are processed to obtain the tooth surface error evaluation coefficient, thereby more accurately quantifying the degree of deviation between the spline key teeth and the design theoretical contour, thereby achieving more accurate path initial planning.

[0032] 3. By obtaining the minimum value of the dynamic contact area from the preset database and comparing the dynamic contact area with the minimum value of the dynamic contact area, if the dynamic contact area is not less than the minimum value of the dynamic contact area, the adjustment effect evaluation coefficient is recorded as 0, otherwise the adjustment effect evaluation coefficient is obtained by summing up the results of processing the hysteresis, transmission error and dynamic contact area respectively, so as to more intuitively understand the shaping effect of the helix angle and plan a more accurate shaping path. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A flow chart of a method for adjusting the helix angle of a spline key tooth provided in an embodiment of the present application;

[0034] Figure 2 The internal spline structure diagram provided in the embodiment of the present application;

[0035] Figure 3 The external spline structure diagram provided in the embodiment of the present application;

[0036] Figure 4 A nephogram of contact stress on the tooth surface of an external spline with a 0° helix angle provided in an embodiment of the present application;

[0037] Figure 5 A 5° helix angle external spline tooth surface contact stress cloud diagram provided in an embodiment of the present application;

[0038] Figure 6 A contact stress cloud diagram of an external spline tooth surface with an 8° helix angle provided in an embodiment of the present application;

[0039] Figure 7 A 10° helix angle external spline tooth surface contact stress cloud diagram provided in an embodiment of the present application;

[0040] Figure 8 A contact stress cloud diagram of a 12° helix angle external spline tooth surface provided in an embodiment of the present application;

[0041] Fig. 9 A contact stress cloud diagram of a 15° helix angle external spline tooth surface provided in an embodiment of the present application;

[0042] Fig.10 A graph showing the maximum contact stress reduction rate of a spline tooth surface provided in an embodiment of the present application;

[0043] Fig.11 A schematic diagram of the adjustment effect evaluation coefficient according to the hysteresis provided in the embodiment of the present application;

[0044] Fig.12 A schematic diagram of the adjustment effect evaluation coefficient according to the transmission error provided in the embodiment of the present application;

[0045] Fig.13 A schematic diagram of the change in the adjustment effect evaluation coefficient with the dynamic contact area provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The embodiment of the present application solves the problem of low accuracy of machining path optimization in the process of helix angle modification in the prior art by providing a method for adjusting the helix angle modification of spline teeth. The stress data obtained by stress detection is introduced, and then the modification area is divided according to the helix angle structure of the spline teeth and each modification area is recorded as a to-be-modified area. At the same time, the to-be-modified areas are numbered, and the minimum roughness limit is obtained from a preset database, and the tooth surface data and the minimum roughness limit are processed to obtain a tooth surface error evaluation coefficient for initial path planning. Then, the machining error evaluation coefficient is obtained based on the machining data and the stress data to determine whether to perform dynamic path optimization. Finally, the minimum dynamic contact area value is obtained from the preset database, and the dynamic contact area is compared with the minimum dynamic contact area value. If the dynamic contact area is not less than the minimum dynamic contact area value, the adjustment effect evaluation coefficient is recorded as 0, otherwise the results of processing the backlash, transmission error and dynamic contact area are respectively summed to obtain the adjustment effect evaluation coefficient to determine whether to re-plan the path, thereby improving the accuracy of machining path optimization in the process of helix angle modification.

[0047] The technical solution in the embodiment of the present application is to solve the problem of low accuracy of machining path optimization in the above-mentioned helix angle modification process, and the overall idea is as follows:

[0048] The tooth surface error evaluation coefficient is used to perform initial path planning, and then the machining error evaluation coefficient is obtained based on the machining data and stress data to determine whether to perform dynamic path optimization. Finally, the adjustment effect evaluation coefficient is obtained through test data to determine whether to replan the path, thereby achieving the effect of improving the accuracy of machining path optimization during the helix angle modification process.

[0049] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0050] like Figure 1 FIG. 1 is a flow chart of a method for adjusting the helix angle of a spline key tooth provided in an embodiment of the present application, the method comprising the following steps:

[0051] Before the helix angle modification, stress detection is introduced to monitor the stress of the spline key teeth during the whole process of helix angle modification to obtain the corresponding stress data. Stress detection includes the input of basic expressions for spline parametric modeling and helix angle parametric correction, the generation of helical spline pair model by UG software, meshing after segmentation of the complex structure model imported into Hypermesh software, and finite element simulation calculation of the divided mesh units by Abaqus software, and comparative analysis of the contact stress of spline tooth surfaces with different helix angles; the tooth surface data is obtained in real time through the measuring equipment, and the tooth surface error evaluation coefficient is obtained based on the tooth surface data. Perform initial path planning, and the tooth surface error evaluation coefficient is used to quantify the degree of deviation between the spline key tooth and the designed theoretical profile; during the helix angle modification and adjustment process, the processing data is obtained by detecting the sensor, and the processing error evaluation coefficient is obtained based on the processing data and stress data to determine whether to perform dynamic path optimization. The processing error evaluation coefficient is used to quantify the accumulated errors generated during the processing process; after the helix angle modification and adjustment process, the test data is obtained by the test instrument, and the adjustment effect evaluation coefficient is obtained based on the test data to determine whether to re-plan the path. The adjustment effect evaluation coefficient is used to quantify the effect of the helix angle modification adjustment of the spline key tooth.

[0052] In this embodiment, stress detection combines 3D modeling software UG, meshing software Hypermesh and finite element software Abaqus to simulate and analyze the stress on the helix angle of the spline key tooth in real time, providing more data basis for the planning of the helix angle modification path; before modification, quantifying the deviation between the tooth surface error and the design theoretical contour helps to determine the rationality of the initial path planning and ensure that the processing path conforms to the theoretical design, and the comprehensive analysis of the processing data and stress data is conducive to the dynamic adjustment of the modification path to deal with the modification path problems caused during the processing; through monitoring, evaluation and optimization of the whole process, not only the accuracy of the processing path optimization during the helix angle modification process is improved, but also the efficiency of the helix angle modification adjustment is improved and the performance and reliability of the spline key tooth are improved.

[0053] It should be explained that the parametric modeling of the spline first requires the input of basic parameters, which include but are not limited to the number of teeth, module, pressure angle and tooth width. The basic parameters are input into the basic parameter expression of the spline, which specifically includes the involute equation and the helix equation. The involute equation and the helix equation are called from the python matplotlib library, and different helical spline pair models are obtained by changing the numerical values ​​of the basic parameters; then the helical spline pair model is generated through the UG software, and the helical spline pair model means drawing the spline tooth profile according to the involute equation and drawing a model with a helix angle through drawing commands, and the drawing commands include but are not limited to stretching and sweeping; then the helical spline pair model is imported into the Hypermesh software; and the contact of the helical spline pair teeth is a nonlinear problem, and the contact between the spline key teeth is set to a surface-to-surface hard contact mode, wherein the spline pair teeth include internal splines and external splines, as shown in the following example. Figure 2 As shown, it is a diagram of the internal spline structure provided in the embodiment of the present application, such as Figure 3 As shown, it is a structural diagram of an external spline provided in an embodiment of the present application; since the internal spline is stiffer than the external spline, the tooth surface of the internal spline is set as the main surface and the end surface is fixed; the tooth surface of the external spline is set as the slave surface, and torque is applied through reference point coupling, and then the penalty function contact algorithm is used to perform finite element calculations. The penalty function contact algorithm represents a mathematical method for simulating the interaction between the surfaces of two or more objects when they contact each other.

[0054] Specifically, Figure 4 The contact stress cloud diagram of the tooth surface of the external spline with a 0° helix angle provided in the embodiment of the present application is as follows: Figure 5 A 5° helix angle external spline tooth surface contact stress cloud diagram provided in an embodiment of the present application; Figure 6 A contact stress cloud diagram of an external spline tooth surface with an 8° helix angle provided in an embodiment of the present application; Figure 7 A 10° helix angle external spline tooth surface contact stress cloud diagram provided in an embodiment of the present application; Figure 8 A contact stress cloud diagram of a 12° helix angle external spline tooth surface provided in an embodiment of the present application; Fig. 9 The contact stress cloud diagram of the external spline tooth surface with a helix angle of 15° provided in the embodiment of the present application compares the contact stress of the spline pair with helix angles of 0°, 5°, 8°, 10°, 12° and 15°. The results show that the spline pair tooth surface stress is reduced after the helix angle is modified. Compared with the tooth surface contact stress of the 0° helix angle, the spline tooth surface contact stress of the 5° helix angle is reduced by 9.33%; the spline tooth surface contact stress of the 8° helix angle is reduced by 21.26%; the spline tooth surface contact stress of the 10° helix angle is reduced by 26.55%; the spline tooth surface contact stress of the 12° helix angle is reduced by 30.62%, and the spline tooth surface contact stress of the 15° helix angle is reduced by 32.93%; as shown in detail Fig.10 As shown, Fig.10The maximum contact stress reduction rate curve of the spline tooth surface provided in the embodiment of the present application is as follows: Fig.10 It can be seen that as the helix angle increases, the maximum contact stress reduction rate of the spline tooth surface also increases. Fig.10 The change of the maximum contact stress on the spline tooth surface is more intuitively displayed; through comparative analysis of the above data, the helix angle modification of the involute spline pair teeth can optimize the tooth surface contact state, make the working engagement of the spline pair more stable, and effectively improve the transmission accuracy; at the same time, the stress data of the spline tooth surface with different helix angles (i.e., contact stress and contact stress reduction rate) are obtained, which is conducive to improving the accuracy of machining path optimization during the helix angle modification process.

[0055] It should be added that the stress data includes contact stress and contact stress reduction rate; the tooth surface data includes tooth profile deviation value, tooth height error, tooth direction error and surface roughness; the processing data includes cutting force, spindle speed, tool wear and tool temperature; the test data includes backlash, transmission error and dynamic contact area.

[0056] In this embodiment, the tooth profile deviation value and the tooth height error are measured by a three-dimensional measuring machine, the tooth direction error is measured by a gear measuring instrument, and the surface roughness is measured by a roughness meter; the cutting force is collected by a dynamic force sensor, the spindle speed is obtained by a spindle monitoring system, the tool wear is collected by a tool wear monitoring sensor, and the tool temperature is measured by an infrared thermometer; the backlash and transmission error are collected by a gear transmission performance tester, and the dynamic contact area is obtained by a dynamic contact analysis system; the collection of the above data helps to provide strong data support for the subsequent helix angle modification adjustment analysis.

[0057] It should be understood that the stress data acquisition process, through the close collaboration of 3D modeling, meshing and finite element simulation, can accurately calculate the tooth contact stress and stress reduction rate of the helical spline under torque loading, providing reliable data support for structural optimization design; its high precision and high efficiency are particularly suitable for performance optimization and reliability improvement of complex mechanical transmission systems, providing important technical support for modern machinery manufacturing.

[0058] Furthermore, the specific process of performing initial path planning based on the tooth surface error evaluation coefficient obtained from the tooth surface data is as follows:

[0059] According to the helix angle structure of the spline teeth, the modification area is divided and each modification area is recorded as an area to be modified, and the areas to be modified are numbered; the minimum limit value of roughness is obtained from the preset database, and the tooth surface data and the minimum limit value of roughness are processed to obtain the tooth surface error evaluation coefficient.

[0060] The specific limiting expression of the tooth surface error evaluation coefficient is as follows:

[0061] ;

[0062] In the formula, n represents the number of the area to be modified. , Indicates the total number of areas to be reshaped. Indicates the tooth profile deviation value of the nth area to be modified, represents the tooth height error of the nth area to be modified, represents the tooth direction error of the nth area to be modified, represents the surface roughness of the nth area to be modified, Indicates the minimum roughness limit, Represents the tooth surface error evaluation coefficient of the nth area to be modified.

[0063] In this embodiment, the algorithm combines the tooth profile deviation value, tooth height error, tooth direction error and surface roughness and the corresponding minimum roughness limit value for comprehensive analysis to obtain the tooth surface error evaluation coefficient, wherein the formula is divided into two cases by judging the surface roughness. When the surface roughness is not greater than the minimum roughness limit value, as the tooth profile deviation value, tooth height error, and tooth direction error increase, and as the surface roughness approaches the minimum roughness limit value, the tooth surface error evaluation coefficient becomes larger, indicating that the current spline key tooth deviates more from the design theoretical profile, and the corresponding processing technology needs to be modified and adjusted; wherein, the tooth profile deviation value, tooth height error, and tooth direction error increase, and the surface roughness becomes closer to the minimum roughness limit value, the tooth surface error evaluation coefficient becomes larger, indicating that the current spline key tooth deviates more from the design theoretical profile, and the corresponding processing technology needs to be modified and adjusted; When the difference is larger, the accumulation of tooth height errors may cause an increase in tooth height errors. The increase in tooth height errors will increase the local contact pressure between the tooth top and the tooth root, thereby aggravating friction and causing an increase in surface roughness. The tooth direction error will affect the local contact pressure distribution on the tooth surface, and the uneven contact pressure will aggravate the wear in the tooth height direction, thereby further increasing the tooth height error. By analyzing the tooth profile deviation value, tooth height error, tooth direction error and surface roughness, the degree of deviation between the spline key tooth and the designed theoretical profile is more accurately quantified, which helps to improve the accuracy of machining path optimization during helix angle modification.

[0064] Specifically, the minimum roughness limit is obtained from a preset database. In a specific embodiment, the minimum roughness limit is set by relevant professionals according to specific modification conditions. For example, if the spline key teeth are aviation precision gears, the minimum roughness limit can generally be assumed to be 0.8 μm.

[0065] Furthermore, the specific steps of initial path planning are as follows:

[0066] S1, compare the tooth surface error evaluation coefficient with the tooth surface evaluation interval to determine the processing technology, which includes rough processing, semi-finishing and finishing; S2, determine the path curve according to the gear geometry parameters of the spline key teeth, the path curve includes axial path, radial path and compound path, and the gear geometry parameters are used to describe the physical properties of the spline key tooth gear; S3, determine the cutting parameters according to the processing technology, and the cutting parameters include cutting depth, feed speed and cutting speed; S4, generate the initial processing path in the CAM software, and the initial processing path covers the area to be modified.

[0067] In this embodiment, the gear geometric parameters include but are not limited to the number of teeth, pitch circle diameter, pressure angle, tooth width, helix angle, tooth pitch and tooth thickness; when there is an error between the tooth width and the tooth width of the theoretical profile, the corresponding axial path is determined, that is, the tooth direction error is corrected along the tooth width direction; when there is an error between the tooth height and the tooth height of the theoretical profile, the corresponding radial path is determined, that is, the tooth profile error is corrected along the tooth height direction; when there are errors between the tooth direction and the tooth profile and the tooth direction and the tooth profile of the theoretical profile, the corresponding composite path is determined, that is, the shaping path is adjusted in combination with the tooth direction and the tooth profile; the path curve clarifies the processing range, centrally corrects the tooth surface error, and ensures that the processing trajectory is consistent with the tooth profile. The curves are consistent, which improves the quality of shaping. Among them, the cutting depth is set in stages according to the shaping amount. The depth gradually increases during rough machining and gradually decreases during fine machining. The feed speed is adjusted according to the tool and machine tool capabilities, and the speed gradually decreases during fine machining. The cutting speed is set according to the material properties and tool characteristics to avoid heat accumulation and tool wear. By combining tooth surface error evaluation, path curve selection and automatic path generation, the accuracy, efficiency and reliability of helix angle shaping are effectively improved. At the same time, the optimized processing technology and cutting parameters ensure high-quality surface roughness and tooth surface contact performance, providing important technical support for complex gear processing.

[0068] Specifically, the specific process of comparing the tooth surface error evaluation coefficient with the tooth surface evaluation interval to determine the machining process is as follows:

[0069] The tooth surface evaluation interval is obtained from the preset database, and the tooth surface evaluation interval includes the first tooth surface evaluation interval, the second tooth surface evaluation interval and the third tooth surface evaluation interval; if the tooth surface error evaluation coefficient belongs to the first tooth surface evaluation interval, the processing technology of the area to be modified is rough machining; if the tooth surface error evaluation coefficient belongs to the second tooth surface evaluation interval, the processing technology of the area to be modified is semi-finishing; if the tooth surface error evaluation coefficient belongs to the third tooth surface evaluation interval, the processing technology of the area to be modified is finishing.

[0070] Specifically, the tooth surface evaluation interval is obtained from a preset database. In a specific embodiment, the tooth surface data corresponding to rough machining in the historical data is substituted into the specific restriction expression of the tooth surface error evaluation coefficient to obtain the mean of the corresponding data set, which is recorded as the first mean value, and the tooth surface data corresponding to fine machining is substituted into the specific restriction expression of the tooth surface error evaluation coefficient to obtain the mean of the corresponding data set, which is recorded as the second mean value. The range corresponding to 0 to the first mean value is recorded as the first tooth surface evaluation interval, and the range corresponding to the first mean value and the second mean value is recorded as the second tooth surface evaluation interval, otherwise it is recorded as the third tooth surface evaluation interval.

[0071] Furthermore, the specific process of obtaining the machining error evaluation coefficient is as follows:

[0072] Reference machining data and reference stress data are obtained from a preset database, wherein the reference machining data include minimum cutting force, maximum cutting force, minimum spindle speed, maximum spindle speed, critical tool wear value and tool temperature limit value, and the reference stress data include minimum contact stress, maximum contact stress, minimum contact stress reduction rate and maximum contact stress reduction rate; machining evaluation weight factors are obtained from a preset database, wherein the machining evaluation weight factors include machining weight factors and stress weight factors; machining evaluation indicators are obtained according to the reference machining data corresponding to the machining data, wherein the machining evaluation indicators include cutting force indicators, spindle speed indicators, tool wear indicators and tool temperature indicators; stress evaluation indicators are obtained according to the stress data and the corresponding reference stress data, wherein the stress evaluation indicators include contact stress indicators and contact stress reduction rate indicators; machining error evaluation coefficients are obtained based on the machining evaluation indicators, stress evaluation indicators and machining evaluation weight factors.

[0073] The specific limiting expression of the machining error evaluation coefficient is as follows:

[0074] ;

[0075] ; ;

[0076] ;

[0077] ;

[0078] ; ;

[0079] ;

[0080] ;

[0081] In the formula, n represents the number of the area to be modified. , Indicates the total number of areas to be reshaped. represents the processing index of the nth area to be modified, represents the stress index of the nth area to be modified, represents the cutting force index of the nth area to be modified, Indicates the spindle speed index of the nth area to be repaired, Represents the tool wear index of the nth area to be repaired, Represents the tool temperature index of the nth area to be modified, represents the contact stress index of the nth area to be modified, It represents the contact stress reduction rate index of the nth area to be modified, represents the cutting force of the nth area to be modified, Indicates the spindle speed of the nth area to be modified, represents the tool wear amount of the nth area to be modified, represents the tool temperature of the nth area to be modified, represents the contact stress of the nth area to be modified, represents the contact stress reduction rate of the nth area to be modified, Indicates the minimum cutting force, represents the maximum cutting force, Indicates the minimum spindle speed. Indicates the maximum spindle speed. Indicates the critical value of tool wear, Indicates the tool temperature limit, represents the minimum contact stress, represents the maximum contact stress, Indicates the minimum contact stress reduction rate, Indicates the maximum value of contact stress reduction rate, represents the processing weight factor, represents the stress weight factor, Represents the machining error evaluation coefficient of the nth area to be modified.

[0082] In this embodiment, the algorithm combines the processing evaluation index, the stress evaluation index and the processing evaluation weight factor for comprehensive analysis to obtain the processing error evaluation coefficient, wherein as the processing index and the stress index increase, the value of the processing error evaluation coefficient becomes smaller, indicating that the error in the processing process has a greater impact on the shaping path; wherein the processing index is the sum of the cutting force index, the spindle speed index, the tool wear index and the tool temperature index, and when the cutting force deviates more from the maximum cutting force value or the minimum cutting force value, the cutting force index becomes larger, indicating that the cutting force has a greater impact on the shaping path, and similarly, when the spindle speed deviates more from the maximum spindle speed value or the minimum spindle speed value, the spindle speed index becomes larger, indicating that the spindle speed has a greater impact on the shaping path; when the tool wear is greater than the tool wear critical value, the tool wear index becomes larger, indicating that the tool wear has a greater impact on the shaping path, and when the tool temperature is greater than the tool temperature limit, the tool stability index becomes larger, indicating that the tool temperature has a greater impact on the shaping path.

[0083] In addition, the stress index represents the sum of the contact stress index and the contact stress reduction rate index. When the contact stress deviates from the maximum contact stress value or the minimum contact stress value, the contact stress index becomes larger, indicating that the contact stress has a greater impact on the shaping path. Similarly, when the contact stress reduction rate deviates from the maximum contact stress reduction rate or the minimum contact stress reduction rate, the contact stress reduction rate index becomes larger, indicating that the contact stress reduction rate has a greater impact on the shaping path. Therefore, through the analysis of processing indicators and stress indicators, it is helpful to understand the situation of the shaping path more accurately during the processing process, so as to take corresponding measures in time for optimization, and thus obtain a more accurate planning path.

[0084] Specifically, assuming that the processing weight factor is 0.5 and the stress weight factor is 0.5, the data change table of the processing error evaluation coefficient can be obtained, as shown in Table 1:

[0085] Table 1 Data change table of machining error evaluation coefficient

[0086] ;

[0087] It can be seen from Table 1 that as the machining index and stress index increase, the machining error evaluation coefficient decreases, indicating that the machining index, stress index and machining error evaluation coefficient are negatively correlated. For example, when the machining index increases from 0.4 in the first row to 3.2 in the sixth row, the stress index increases from 0.2 in the first row to 2.0 in the sixth row, and the machining error evaluation coefficient decreases from 0.89 in the first row to 0.04 in the sixth row, it is intuitively proved that the machining index, stress index and machining error evaluation coefficient are negatively correlated, indicating that the larger the machining error evaluation coefficient, the smaller the possibility of errors in the machining process, and the smaller the impact on the modification path; in addition, if the cutting force is increased, the cutting heat will increase, resulting in an increase in tool temperature and tool wear. At the same time, the spindle speed may be limited, resulting in a decrease in spindle speed. If the spindle speed is increased, the cutting force can be reduced, but it will cause the tool temperature to increase, aggravate tool wear and increase tool wear, affecting machining stability. Through the analysis of machining data, it is helpful to understand the machining conditions of more accurate modification adjustments, thereby improving the accuracy of machining path optimization during helix angle modification.

[0088] Specifically, the reference processing data is obtained from a preset database. In a specific embodiment, the reference processing data can be obtained by consulting the data. For example, if the material of the spline key teeth to be processed is steel, the minimum cutting force is 200N, the maximum cutting force is 1500N, the minimum spindle speed is 100RPM, the maximum spindle speed is 600RPM, the tool wear critical value is 150μm, and the tool temperature limit is 700℃.

[0089] Specifically, the reference stress data is obtained from a preset database. In a specific embodiment, the reference stress data can be obtained by consulting the data. For example, if it is a steel spline key tooth, the minimum contact stress is 150MPa, the maximum contact stress is 300MPa, the minimum contact stress reduction rate is 15%, and the maximum contact stress reduction rate is 30%.

[0090] Specifically, the processing weight factor refers to the weight value corresponding to the processing indicator in the preset database. This weight value reflects the degree of influence of the processing indicator on the processing error evaluation coefficient. In practical applications, the weight matching the processing indicator can be directly searched and obtained from the preset database. This correspondence is a pre-set mapping relationship. For example, during the processing process, the weights corresponding to the processing indicators and the processing error evaluation coefficients preset in the preset database constitute a mapping set. When the real-time processing indicators are input into this mapping set, the corresponding weight value can be obtained. It should be noted here that the mapping relationship is one-to-one. In this example, the value range of the processing weight factor is limited to between 0 and 1.

[0091] Specifically, the sum of the processing weight factor and the stress weight factor is 1.

[0092] Furthermore, the specific process of determining whether to perform dynamic path optimization is as follows: obtaining an optimization threshold from a preset database, the optimization threshold being used to determine whether to perform dynamic path optimization; determining the relationship between a machining error evaluation coefficient and the optimization threshold: if the machining error evaluation coefficient is not less than the optimization threshold, dynamic path optimization is not performed; if the machining error evaluation coefficient is less than the optimization threshold, dynamic path optimization is performed; dynamic path optimization includes shortening non-cutting paths and dynamically adjusting cutting parameters; shortening non-cutting paths means adjusting the cutting start and end positions so that the tool moves along the shortest path to the next cutting position, and the shortest path is provided by the CAM software; dynamic cutting parameter adjustment adjusts the cutting parameters in real time through a PID controller.

[0093] In this embodiment, an efficient, precise and intelligent machining process is comprehensively realized through threshold-driven optimization selection, minimization of non-cutting paths and dynamic adjustment of cutting parameters. This not only reduces machining time and cost, but also improves machining reliability and stability. CAM (Computer Aided Manufacturing) software and PID (Proportional-Integral-Derivative) controller are used to achieve path and parameter optimization, improve the automation level of the production line, and fully reflect the intelligent advantages of modern manufacturing.

[0094] Specifically, the optimization threshold is obtained from a preset database. In a specific embodiment, the processing data and stress data corresponding to the situation where the processing process path problem occurs in the historical data are substituted into the specific restriction expression of the processing error evaluation coefficient to obtain the corresponding data set, and the result of the mean operation of the data set is recorded as the optimization threshold.

[0095] Furthermore, the specific process of obtaining the adjustment effect evaluation coefficient is as follows: obtain the minimum value of the dynamic contact area from the preset database, and compare the dynamic contact area with the minimum value of the dynamic contact area: if the dynamic contact area is not less than the minimum value of the dynamic contact area, then the adjustment effect evaluation coefficient is recorded as 0; if the dynamic contact area is less than the minimum value of the dynamic contact area, then the results of processing the hysteresis, transmission error and dynamic contact area respectively are summed to obtain the adjustment effect evaluation coefficient.

[0096] The specific limiting expression of the adjustment effect evaluation coefficient is as follows:

[0097] ;

[0098] In the formula, n represents the number of the area to be modified. , Indicates the total number of areas to be reshaped. Indicates the hysteresis of the nth area to be modified, represents the transmission error of the nth area to be modified, represents the dynamic contact area of ​​the nth area to be modified, represents the minimum dynamic contact area, Represents the adjustment effect evaluation coefficient of the nth area to be modified.

[0099] In this embodiment, the algorithm combines the hysteresis, transmission error and dynamic contact area for comprehensive analysis to obtain the adjustment effect evaluation coefficient, where the hysteresis, transmission error and adjustment effect evaluation coefficient are negatively correlated, while the dynamic contact area and adjustment effect evaluation coefficient are positively correlated, as shown in the following formula: Figure 11-13 shown.

[0100] Specifically, assuming that the minimum dynamic contact area is 10 square millimeters, Fig.11 As shown, Fig.11 The schematic diagram of the adjustment effect evaluation coefficient changing with the hysteresis provided in the embodiment of the present application shows that when the transmission error is 2 microns and the dynamic contact area is 15 square millimeters, as the hysteresis increases, the image shows a downward trend, and the adjustment effect evaluation coefficient gradually decreases; Fig.12 As shown, Fig.12 The schematic diagram of the adjustment effect evaluation coefficient changing with the transmission error provided in the embodiment of the present application, when the hysteresis is 2 microns and the dynamic contact area is 15 square millimeters, as the transmission error increases, the image shows a downward trend, and the adjustment effect evaluation coefficient gradually decreases; Fig.13 As shown, Fig.13 A schematic diagram of the change of the adjustment effect evaluation coefficient with the dynamic contact area provided in the embodiment of the present application, when the hysteresis is 2 microns and the transmission error is 2 microns, as the dynamic contact area increases, the image shows an upward trend, and the adjustment effect evaluation coefficient gradually increases, indicating that the smaller the hysteresis and transmission error, the better the effect of the shaping adjustment, and the larger the dynamic contact area, the more conducive to the planning of the shaping path, and the hysteresis is mainly manifested as gear clearance, which will cause uneven dynamic contact area, directly leading to an increase in transmission error. The transmission error is the core of the precision problem in the gear system, and is affected by the coupling of the hysteresis and the dynamic contact area, and further reacts on the stability of the gear system. The dynamic contact area is the key to the bearing capacity of the gear and is directly affected by the hysteresis. At the same time, dynamic changes will aggravate the transmission error. The analysis of the hysteresis, transmission error and dynamic contact area helps to more intuitively monitor the effect of the shaping path adjustment, so as to take corresponding measures to intervene in time, thereby achieving the improvement of the accuracy of the processing path optimization during the helix angle shaping process.

[0101] Specifically, the minimum value of the dynamic contact area is obtained from a preset database. In a specific embodiment, the minimum value of the dynamic contact area is set by relevant professionals according to specific modification conditions. For example, it is generally assumed that the minimum value of the dynamic contact area is 60% of the tooth width.

[0102] Furthermore, the specific process of determining whether to perform path replanning is as follows: obtaining a planning threshold from a preset database, and the planning threshold is used to determine whether to perform path replanning; determining the relationship between the adjustment effect evaluation coefficient and the planning threshold: if the adjustment effect evaluation coefficient is not less than the planning threshold, path replanning is not performed; if the adjustment effect evaluation coefficient is less than the planning threshold, path replanning is performed, and when the monitored adjustment effect evaluation coefficient is not less than the planning threshold, path replanning is terminated, otherwise path replanning is continued; path replanning means reacquiring the tooth surface data of the area to be modified to obtain the tooth surface error evaluation coefficient and replanning the path based on the tooth surface error evaluation coefficient until the adjustment effect evaluation coefficient is not less than the planning threshold.

[0103] In this embodiment, by adjusting the dynamic comparison of the effect evaluation coefficient and the planning threshold, the triggering and termination conditions of the path planning are intelligently determined, and the path optimization is achieved in combination with the latest error data, thereby improving the processing efficiency, accuracy and resource utilization. Its automation and intelligent characteristics are particularly suitable for processing requirements of high precision, complex shapes or variable working conditions.

[0104] Specifically, the planning threshold is obtained from a preset database. In a specific embodiment, the test data corresponding to the situation where the path needs to be re-planned after processing in the historical data is substituted into the specific restriction expression of the adjustment effect evaluation coefficient to obtain the corresponding data set, and the result of the mean operation of the data set is recorded as the planning threshold.

[0105] In summary, the embodiment of the present application performs initial path planning through the obtained tooth surface error evaluation coefficient, then obtains the processing error evaluation coefficient based on the processing data and stress data to determine whether to perform dynamic path optimization, and finally obtains the adjustment effect evaluation coefficient through the test data to determine whether to re-plan the path, thereby providing a more reasonable processing path for the helix angle modification, thereby improving the accuracy of the processing path optimization during the helix angle modification process, and effectively solving the problem of low accuracy of processing path optimization during the helix angle modification process in the prior art.

[0106] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0107] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0108] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0109] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0110] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0111] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for adjusting the helix angle of a spline key tooth, characterized in that: The following steps are involved: Before the helix angle modification, stress detection is introduced to monitor the stress of the spline key teeth during the whole process of helix angle modification to obtain corresponding stress data. The stress detection includes the input of basic expressions for spline parametric modeling and helix angle parametric correction, the generation of a helical spline pair model by UG software, meshing after segmentation of the complex structure model imported into Hypermesh software, and finite element simulation calculation of the divided mesh units by Abaqus software, and comparative analysis of the contact stress magnitudes of the spline tooth surfaces with different helix angles; The tooth surface data is acquired in real time by measuring equipment, and the initial path planning is performed based on the tooth surface error evaluation coefficient obtained from the tooth surface data, wherein the tooth surface error evaluation coefficient is used to quantify the degree of deviation between the spline key teeth and the designed theoretical profile; During the helix angle modification and adjustment process, the processing data is obtained through the detection sensor, and the processing error evaluation coefficient is obtained based on the processing data and stress data to determine whether to perform path dynamic optimization. The processing error evaluation coefficient is used to quantify the accumulated errors generated during the processing; After the helix angle modification process, test data is obtained through a testing instrument, and an adjustment effect evaluation coefficient is obtained based on the test data to determine whether to perform path replanning. The adjustment effect evaluation coefficient is used to quantify the effect of the helix angle modification adjustment of the spline key teeth.

2. A method for adjusting the helix angle of a spline key tooth according to claim 1, characterized in that: The stress data include contact stress and contact stress reduction rate; The tooth surface data includes tooth profile deviation value, tooth height error, tooth direction error and surface roughness; The processing data includes cutting force, spindle speed, tool wear and tool temperature; The test data include backlash, transmission error and dynamic contact area.

3. A method for adjusting the helix angle of a spline key tooth according to claim 2, characterized in that: The specific process of performing initial path planning based on the tooth surface error evaluation coefficient obtained based on the tooth surface data is as follows: Divide the modification area according to the helix angle structure of the spline key teeth and record each modification area as a to-be-modified area, and number the to-be-modified areas; The minimum limit value of roughness is obtained from a preset database, and the tooth surface data and the minimum limit value of roughness are processed to obtain a tooth surface error evaluation coefficient; The specific limiting expression of the tooth surface error evaluation coefficient is as follows: ； In the formula, n represents the number of the area to be modified. , Indicates the total number of areas to be reshaped. Indicates the tooth profile deviation value of the nth area to be modified, represents the tooth height error of the nth area to be modified, represents the tooth direction error of the nth area to be modified, represents the surface roughness of the nth area to be modified, Indicates the minimum roughness limit, Represents the tooth surface error evaluation coefficient of the nth area to be modified.

4. A method for adjusting the helix angle of a spline key tooth according to claim 3, characterized in that: The specific steps of the initial path planning are as follows: S1, comparing the tooth surface error evaluation coefficient with the tooth surface evaluation interval to determine the machining process, wherein the machining process includes rough machining, semi-finishing machining and finishing machining; S2, determining a path curve according to gear geometric parameters of the spline teeth, wherein the path curve includes an axial path, a radial path, and a composite path; S3, determining cutting parameters according to the machining process, wherein the cutting parameters include cutting depth, feed rate and cutting speed; S4, generating an initial machining path in CAM software, wherein the initial machining path covers the area to be modified.

5. A method for adjusting the helix angle of a spline key tooth according to claim 4, characterized in that: The specific process of comparing the tooth surface error evaluation coefficient with the tooth surface evaluation interval to determine the machining process is as follows: Acquire a tooth surface evaluation interval from a preset database, wherein the tooth surface evaluation interval includes a first tooth surface evaluation interval, a second tooth surface evaluation interval, and a third tooth surface evaluation interval; If the tooth surface error evaluation coefficient belongs to the first tooth surface evaluation interval, the machining process of the area to be modified is rough machining; If the tooth surface error evaluation coefficient belongs to the second tooth surface evaluation interval, the machining process of the area to be modified is semi-finishing; If the tooth surface error evaluation coefficient belongs to the third tooth surface evaluation interval, the machining process of the area to be modified is fine machining.

6. A method for adjusting the helix angle of a spline key tooth according to claim 2, characterized in that: The specific process of obtaining the machining error evaluation coefficient is as follows: Acquire reference processing data and reference stress data from a preset database, wherein the reference processing data includes a minimum cutting force value, a maximum cutting force value, a minimum spindle speed value, a maximum spindle speed value, a tool wear critical value, and a tool temperature limit value, and the reference stress data includes a minimum contact stress value, a maximum contact stress value, a minimum contact stress reduction rate value, and a maximum contact stress reduction rate value; Acquire a processing evaluation weight factor from a preset database, wherein the processing evaluation weight factor includes a processing weight factor and a stress weight factor; Obtaining a machining evaluation index according to reference machining data corresponding to the machining data, wherein the machining evaluation index includes a cutting force index, a spindle speed index, a tool wear index, and a tool temperature index; Obtaining a stress evaluation index according to the stress data and the corresponding reference stress data, wherein the stress evaluation index includes a contact stress index and a contact stress reduction rate index; The machining error assessment coefficient is obtained based on the machining assessment index, the stress assessment index and the machining assessment weight factor.

7. A method for adjusting the helix angle of a spline key tooth according to claim 6, characterized in that: The specific process of determining whether to perform dynamic path optimization is as follows: Obtaining an optimization threshold from a preset database, where the optimization threshold is used to determine whether to perform dynamic path optimization; Determine the relationship between the processing error evaluation coefficient and the optimization threshold: If the machining error evaluation coefficient is not less than the optimization threshold, the path dynamic optimization will not be performed; If the machining error evaluation coefficient is less than the optimization threshold, the path is dynamically optimized; The dynamic path optimization includes shortening the non-cutting path and dynamically adjusting the cutting parameters.

8. A method for adjusting the helix angle of a spline key tooth as claimed in claim 2, characterized in that: The specific process of obtaining the adjustment effect evaluation coefficient is as follows: Get the minimum dynamic contact area value from the preset database and compare the dynamic contact area with the minimum dynamic contact area value: If the dynamic contact area is not less than the minimum dynamic contact area, the adjustment effect evaluation coefficient is recorded as 0; If the dynamic contact area is less than the minimum dynamic contact area, the adjustment effect evaluation coefficient is obtained by summing the results of processing the hysteresis, transmission error and dynamic contact area respectively.

9. A method for adjusting the helix angle of a spline key tooth according to claim 8, characterized in that: The specific process of determining whether to replan the path is as follows: Acquire a planning threshold from a preset database, where the planning threshold is used to determine whether to perform path replanning; Determine the relationship between the adjustment effect evaluation coefficient and the planning threshold: If the adjustment effect evaluation coefficient is not less than the planning threshold, the path will not be replanned; If the adjustment effect evaluation coefficient is less than the planning threshold, the path is replanned. When the monitored adjustment effect evaluation coefficient is not less than the planning threshold, the path replanning is terminated, otherwise the path replanning continues.

10. A method for adjusting the helix angle of a spline key tooth according to claim 1, characterized in that: The stress data is obtained as follows: Drawing a helical spline model by using a three-dimensional modeling software, wherein the helical spline model is used to simulate the helix angle of the spline key teeth; The helical spline model is imported into the meshing software to generate a hexahedral mesh, and then the finite element software is called to simulate and calculate the tooth surface contact stress and contact stress reduction rate under torque loading.

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