Decoupling method and system for axial deformation generated by residual stress of herringbone gear cutting and heat treatment

Abstract

The invention provides a decoupling method for axial deformation generated by residual stress of herringbone gear cutting and heat treatment, and belongs to the field of mechanical manufacturing processes, computer-aided simulation and digital twinning. The method is characterized by comprising the following steps: establishing a cutting process and heat treatment collaborative deformation simulation model; analyzing residual stress distribution and a deformation mechanism in the whole process of blank heat treatment, machining, carburizing heat treatment and the like; obtaining surface residual stress and depth distribution functions under different cutting parameters through orthogonal cutting simulation; designing an experiment, extracting a simulation correction coefficient, a deformation constant and a heat treatment correction coefficient of cutting regeneration stress, and eliminating interference of residual stress of preheat treatment; and deformation prediction and process optimization of a full variable space are realized through a digital twinning technology. The method solves the problem that the cutting regeneration residual stress is difficult to directly observe, obviously improves the machining precision prediction capability, reduces the experiment cost, and is suitable for the field of manufacturing of parts sensitive to residual stress, such as precision gears and thin-wall parts.

Description

[0001] A method and system for decoupling axial deformation caused by residual stress in herringbone gear cutting and heat treatment. Technical Field

[0002] This invention provides a decoupling method and system for axial deformation caused by residual stress during the cutting and heat treatment of herringbone gears, belonging to the fields of mechanical manufacturing processes, computer-aided simulation, and digital twins. Background Technology

[0003] In the machining of herringbone gears, residual stress deformation from cutting and deformation from heat treatment are often the main sources of error in gear accuracy. The residual stresses from cutting and heat treatment interact during machining, leading to complex final deformation of the gear parts and making deformation control difficult. This is especially problematic in applications such as aerospace, automotive transmissions, and high-precision machine tools, where the dimensional stability of gears is extremely critical. This paper proposes a decoupling method for residual stress deformation introduced by cutting and heat treatment. This method can improve part production quality and efficiency, increase machining accuracy, reduce trial-and-error costs, enhance process controllability, and promote the transformation of manufacturing processes towards intelligence and data-driven approaches.

[0004] Predicting deformation during the cutting process solely from the perspective of machining is explored in several areas. For example, Ma Yuan and Feng Pingfa et al. from Tsinghua University Shenzhen Graduate School provided a method combining finite element simulation analysis and cutting force-thermal coupling theory modeling (CN201711484933.2). This method simulates the evolution of the internal stress field in a blank structural part containing initial residual stress during roughing and finishing, enabling the prediction of final machining residual stress and deformation. Another example is Wang Mingwei and Zhou Jingtao et al. from Northwestern Polytechnical University, who presented a data-driven method for predicting cutting residual stress under time-varying conditions (CN202410572762.2), belonging to the field of machining technology. This method collects time-varying signals, non-time-varying signals, and cutting residual stress values ​​during the experimental process. It uniformly represents and processes the non-time-varying signals, performs adaptive feature extraction on the time-varying signal data, designs a feature extraction method for low-dimensional representation of high-dimensional data, and then fuses the processed non-time-varying signals with the time-varying signals as input to a CNN cutting residual stress prediction model. The cutting residual stress value is used as the model output, establishing a complex mapping relationship between the collected data under time-varying working conditions and the final residual stress, thereby realizing online prediction of cutting residual stress.

[0005] There are also many studies on deformation caused by heat treatment. For example, Zhang Zhihua, Wu Ping and others from China Aero Engine Corporation Zhongchuan Machinery Co., Ltd. proposed a method for controlling the deformation of spiral bevel gears during heat treatment (CN201911421635.8). By designing the quenching mold and rationally distributing the cooling oil circuit, and with the expansion ring mold located above the central hole of the rod and applying pressure to the top of the central hole of the rod, the quenching deformation control of the outer circle of the rod and the teeth was realized. For example, Wang Huanmin, Ju Dianwei, and others from Harbin Dong'an Engine Co., Ltd. of China Aero Engine Corporation proposed a method for controlling the deformation of large bevel gears during heat treatment (CN202010362666.7). This method involves: first, copper plating all areas of the part except the bevel tooth area for initial protection; loading the cleaned part with the bevel tooth end facing upwards into the furnace, and using tooling to support the web of the part; performing a first carburizing on the supported part; high-temperature tempering of the carburized part in a protective atmosphere furnace, followed by nitrogen cooling to room temperature; second, copper plating all areas of the cooled part except for the bevel tooth, spline, and journal for initial protection; loading the cleaned part with the bevel tooth end facing upwards into the furnace, and using tooling to support the web of the cleaned part again; performing a first carburizing on the re-supported part; high-temperature tempering of the second carburized part in a protective atmosphere furnace; placing the tempered part in a controlled atmosphere furnace for heating according to preset temperature requirements; and finally, pressure quenching, cooling, tempering, and cooling to room temperature. This method controls the deformation of the gear during heat treatment by changing external conditions.

[0006] Additionally, Rolls-Royce Motor Cars in the United States proposed a method for forming components using solid freeform manufacturing technology (US20080219069), which includes the step of constructing an integrated support structure around the component during the component manufacturing process. By selecting the stiffness provided by the support structure to the component, deformation of the component during manufacturing or subsequent heat treatment is minimized. All of these methods address deformation control by specifically altering a portion of the cutting or heat treatment process; they do not decouple the effects of cutting residual stress and heat treatment residual stress on workpiece deformation, thus failing to comprehensively and accurately predict the final machining deformation of a workpiece.

[0007] Currently, research on the coupling of residual stress on the cutting surface and residual stress from heat treatment is still lacking, and research mainly focuses on residual stress from one aspect. Summary of the Invention

[0008] The technical problem to be solved by this invention is: The purpose of this invention is to provide a decoupling method for axial deformation caused by residual stress in the cutting and heat treatment of herringbone gears, which solves the problem that the residual stress generated during turning is difficult to observe directly, and improves the predictive ability of machining accuracy and reduces experimental costs by utilizing the coupling effect of cutting and heat treatment.

[0009] The technical solution adopted by this invention to solve the above-mentioned technical problems is as follows (invention implementation method): A decoupling method for axial deformation caused by residual stress during the cutting and heat treatment of herringbone gears is disclosed. This method is used to obtain the relationship between the total axial deformation of the herringbone gear and the residual stress from cutting and heat treatment of the workpiece. The method introduces a simulation correction coefficient for residual stress on the regenerated turning surface. C Residual stress-deformation constant on regenerated surfaces K Heat treatment residual stress deformation correction factor C h Based on experimental and simulation results, the relative incremental decoupling method is used to extract the experimental correction constant. Finally, the formula for calculating the total axial deformation of the herringbone gear is:

[0010]

[0011] In the formula: K is the ratio of the difference in deformation between the two workpieces to the difference in surface residual stress; It is the inherent deformation during the carburizing heat treatment process. The results show the residual stress and deformation after heat treatment simulation.

[0012] in This refers to the deformation amount in the heat treatment simulation. The simulated value of residual stress on the machined surface. The values ​​represent the simulated residual stress on the surface during the initial pre-heat treatment.

[0013] The specific implementation of the method includes the following process: 1. First, determine the process flow of the workpiece, and determine its blank heat treatment temperature-time curve, machining parameters and other process parameters.

[0014] 2. Simulate the heat treatment and machining of the workpiece based on the process parameters to obtain the surface residual stress data and length deformation data of the workpiece during heat treatment and machining.

[0015] 3. Select appropriate heat treatment and machining process parameters based on simulation data, and then design experiments to obtain as much test data as possible on length and surface residual stress.

[0016] 4. Measure the surface residual stress and axial dimension data of the specimen. 5. The relative incremental decoupling method is used to separate the coupling effect between cutting regeneration stress and pre-heat treatment stress, and the simulation correction coefficient C, deformation constant K, and heat treatment correction coefficient are extracted.

[0017] Finally, the total deformation can be obtained.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: The key technical points of the decoupling method for axial deformation caused by residual stress in the cutting and heat treatment of herringbone gears provided by this invention are as follows: Establishing a collaborative deformation simulation model of the cutting process and heat treatment; analyzing the residual stress distribution and deformation mechanism throughout the entire process of blank heat treatment, machining, and carburizing heat treatment; obtaining surface residual stress and depth distribution functions under different cutting parameters through orthogonal cutting simulation; designing experiments to extract simulation correction coefficients, deformation constants, and heat treatment correction coefficients for cutting regeneration stress, eliminating interference from residual stress in the pre-heat treatment stage; and achieving deformation prediction and process optimization across the entire variable space through digital twin technology. This method solves the problem of directly observing cutting regeneration residual stress, significantly improves the ability to predict machining accuracy, reduces experimental costs, and is applicable to the manufacturing of precision gears, thin-walled parts, and other components sensitive to residual stress.

[0019] This invention proposes a decoupling method for axial deformation caused by residual stress from machining and heat treatment of herringbone gears. This method addresses the issue that residual stress already exists inside the herringbone gear workpiece before machining, and the surface residual stress generated during machining cannot be directly obtained, lacking observability. This invention introduces a simulation correction coefficient C for surface residual stress generated during turning, a residual stress-deformation constant K (K is the ratio of the difference in deformation between the two workpieces to the difference in surface residual stress), and a deformation correction coefficient for residual stress from heat treatment. Based on experimental and simulation results, three experimental correction constants C, K, and Cm were extracted using the relative incremental decoupling method. h , The final total axial deformation of the herringbone gear was obtained. , Therefore, the axial deformation of the herringbone gear is simulated using the total deformation formula, providing a reference for herringbone gear design.

[0020] This invention decouples and makes observable the regenerative residual stress generated by heat treatment and machining. Through co-simulation of heat treatment and machining, the influence of different cutting parameters on the final deformation is obtained, leading to the acquisition of optimal cutting parameters and improved production efficiency and workpiece quality. Furthermore, through co-simulation and post-processing data analysis, the evolution and distribution of residual stress during the machining of herringbone gears are clarified, allowing for reasonable process optimization and control of workpiece deformation. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1This is a technical roadmap for a decoupling method to address the axial deformation caused by residual stress in the cutting and heat treatment of herringbone gears. Figure 2 It is a process flow chart for the workpiece; Figure 3 It is a graph of the time and temperature of the heat treatment of the raw billet; Figure 4 This is a schematic diagram of a small herringbone gear structure; Figure 5 It is the time-temperature curve of the carburizing heat treatment; Figure 6 This is a schematic diagram of the three elements of cutting; Figure 7 This is a simulation diagram of residual cutting stress; Figure 8 This is a diagram showing the deformation caused by carburizing heat treatment; Figure 9 This is a schematic diagram of an experimental method based on relative incremental decoupling; Figure 10 This is a schematic diagram of the surface residual stress detection points; Figure 11 This is a schematic diagram of the experimental axial dimension measurement. Detailed Implementation

[0022] To clearly illustrate the decoupling method for axial deformation caused by residual stress in the cutting and heat treatment of herringbone gears according to the present invention, the following embodiments and appendices are provided. Figure 1-11 The present invention will be further described, but this should not be construed as limiting the scope of protection of the present invention.

[0023] Step S1: Design the workpiece's technological process, including the following steps: Step (S101): After the blank is heat-treated (101), it is in the blank supply state. After rough turning (102), copper plating (103) is performed for carburizing protection. After the copper layer is turned on the tooth top (104), the tooth surface forming process - milling (105) is carried out. After surface carburizing and quenching (106), the contour is precision turned (107). Finally, the tooth is ground (108) to complete the tooth profile finishing. Step S2: Perform workpiece heat treatment and machining simulation based on process parameters to obtain surface residual stress data and length deformation data for the workpiece after heat treatment and machining; including the following steps: Step (S201): The blank is first subjected to quenching and tempering heat treatment (101). This step is divided into two heat treatment processes: quenching (201) and high-temperature tempering (202). The quenching temperature is (203), the high-temperature tempering temperature is (204), T (205) represents the temperature, and t (206) represents the time. The residual stress and deformation data of the quenching and tempering heat treatment simulation are obtained by computer-aided simulation. Figure 2 As shown; Step (S202): After heat treatment (101) of the blank, rough turning (102) is performed, where the blank is (301) and the rough turning result is (302). The residual stress and deformation data of the cutting simulation are obtained by computer-aided simulation; such as Figure 3 As shown; Step (S203): The workpiece undergoes surface carburizing (106). This step involves multiple heat treatment processes, including: carburizing (401), quenching (402), cryogenic treatment (403), primary tempering (404), and secondary tempering (405), with carburizing temperature (406), quenching temperature (407), cryogenic treatment temperature (408), and tempering temperature (409). Simulation data for the carburizing heat treatment is obtained through computer-aided simulation; for example... Figure 4 As shown; Step S3: Based on the simulation data in Step S2, select the cutting parameter combinations corresponding to the three groups of surface stresses (high, medium, and low); including the following steps: Step (S301): Based on the cutting simulation data obtained in step (S202), design cutting parameters at three levels (high, medium, and low), and design experimental combinations, such as... Figure 8 The diagram shows three test pieces selected to form three combinations. By extracting the difference between the data of every two experimental samples, three sets of usable data can be extracted, thus extracting as much experimental data as possible with minimal experimental cost. Step (S302): Select three groups of surface stresses (high, medium, and low) corresponding to the cutting parameter combinations, and design an orthogonal experimental group. The cutting parameters include: cutting linear velocity V. c (501), cutting depth a p (502) and single-revolution feed rate f (503); Step S4: Measure the surface residual stress and axial dimensions of the specimen; including the following steps: Step (S401): Perform the first surface residual stress test after rough machining in step (S101) (102); Step (S402): Perform the first length detection after milling the teeth in step (S101) (105); Step (S403): Perform a second length inspection after the carburizing heat treatment in step (S101) (106); Step (S404): Perform a second surface residual stress test, following the second length test in step (S305); Step S5: Use the relative incremental decoupling method to separate the coupling effect between cutting regeneration stress and pre-heat treatment stress, and extract the simulation correction coefficient C, deformation constant K, and heat treatment correction coefficient.

[0024] Finally, the total deformation can be obtained. Step S5 includes the following steps: Step (S501): Residual surface stress after rough machining Inherited from residual stress during pre-heat treatment and residual stress on the regenerated surface of the turning process It consists of two parts, where h=0 represents the surface;

[0025] Step (S502): Introduce the simulation correction factor C for residual stress on the turned regenerated surface. The simulated value of residual stress on the machined surface. The simulated values ​​are the residual stress values ​​on the surface after the initial pre-heat treatment.

[0026] Step (S503): Calculate the simulation correction coefficient C, and obtain the formula after transformation;

[0027] in The simulated values ​​of residual stress on the surfaces of workpieces 1 and 2 after turning are represented.

[0028] Step (S504): Introduce the residual stress-deformation constant K on the regenerated surface.

[0029] Where ∆LHeat is the inherent deformation during the carburizing heat treatment process. This represents the deformation released by the residual stress annealing after turning. Subscripts 1 and 2 represent workpiece 1 and workpiece 2, respectively. Step (S505): Obtain the formula for the influence of turning process parameters on the deformation during carburizing heat treatment; Step (S506): Based on the influence of residual stress on the regenerated surface after turning, the deformation amount of residual stress after heat treatment can be further obtained:

[0030] Step (S507): Heat treatment residual stress deformation correction factor for:

[0031] ∆LHeat is the inherent deformation during the carburizing heat treatment process, and ∆LTest is the residual stress deformation result of the heat treatment simulation. Step (S508): Obtain the formula for calculating the total deformation:

[0032] Where ∆L represents the deformation in the heat treatment simulation. The simulated value of residual stress on the machined surface. The values ​​represent the simulated residual stress on the surface during the initial pre-heat treatment.

[0033] The method described in this invention has been verified and achieves the technical effects of this invention.

[0034] A system based on the decoupling method for axial deformation caused by residual stress in the cutting and heat treatment of herringbone gears proposed in this invention has been developed using a computer program. This system has program modules corresponding to the steps of the method described in claim 1. During operation, it executes the steps in the decoupling process for axial deformation caused by residual stress in the cutting and heat treatment of the herringbone gears, thereby calculating the total axial deformation of the herringbone gear. The developed system (software) computer program is stored on a computer-readable storage medium, and the computer program is configured to implement the steps of the method when called by a processor. In other words, this invention is materialized on a carrier, becoming a computer program product.

[0035] Various implementations of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, application-specific integrated circuits (ASICs), computer hardware, firmware, software, and / or combinations thereof. These various implementations may include: implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0036] The computational programs (also referred to as programs, software, software applications, or code) of this invention include machine instructions of a programmable processor and can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, device, and / or apparatus (e.g., disk, optical disk, memory, programmable logic device PLD) for providing machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0037] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method of decoupling axial deformation from residual stress generation by cutting and heat treating of a double helical gear, the method comprising: The method is used for obtaining the relationship between the axial total deformation of the human herringbone gear and the residual stress of the workpiece cutting and heat treatment, and the method introduces a turning regenerated surface residual stress simulation correction coefficient C , regenerated surface residual stress-deformation constant K , heat treatment residual stress deformation correction coefficient C h Through the experimental and simulation results, the experimental correction constant is extracted by using the relative increment decoupling method C , K, C h Finally, the axial total deformation calculation formula of the human herringbone gear is obtained ​ ； ； wherein: K is the ratio of the difference between the deformation of the two workpieces to the difference between the surface residual stresses; is the deformation inherent to the carburizing heat treatment process, is the residual stress deformation result of the heat treatment simulation; wherein is the deformation in the heat treatment simulation, is the simulated residual stress of the turned surface, is the simulated residual stress of the initial prepared heat treated surface.

2. A method of decoupling axial deformation from residual stresses generated by cutting and heat treating of a double helical gear as set forth in claim 1, wherein, The specific implementation process of the method is: Step S1: determining the process flow of the workpiece, determining the blank heat treatment temperature-time curve, and mechanical processing parameters; Step S2: performing workpiece heat treatment and mechanical processing simulation according to the process parameters to obtain surface residual stress data and length deformation data of the workpiece heat treatment and mechanical processing; Step S3: selecting appropriate heat treatment and mechanical processing process parameters according to the simulation data in step S2 to obtain length and surface residual stress test data, and selecting multiple sets of surface stress corresponding to cutting parameter combinations; Step S4: measuring the surface residual stress and axial size data of the test piece; Step S5: The relative incremental decoupling method is used to separate the coupling effects of the cutting regenerative stress and the preliminary heat treatment stress, and the simulation correction coefficient C, the deformation constant K and the heat treatment correction coefficient The total deformation is finally obtained.

3. A method of decoupling axial deformation from residual stresses generated by cutting and heat treating of a double helical gear as set forth in claim 2, wherein, The specific implementation process of step S5 in the method is: Step S501 : rough turning of the rear surface residual stress from the preliminary heat treatment residual stress inheritance item and turning of the regenerative surface residual stress consists of two parts, where h = 0 indicates the surface; Step S502: introduce turning regenerative surface residual stress simulation correction coefficient C, is the turning surface residual stress simulation value, is the initial preparation heat treatment surface residual stress simulation value; ； Step (S503): find the simulation correction coefficient C, and the formula is obtained after transformation; ； wherein representative of the simulated residual stress values of the turned rear surface of the workpiece 1 and the workpiece 2; Step (S504): introduce the regenerative surface residual stress-deformation constant K, ； wherein is the amount of deformation inherent to the carburizing heat treatment process, is the amount of deformation released by the turning regenerative residual stress annealing, the indices 1, 2 stand for the workpiece 1 and the workpiece 2; Step (S505): obtain the influence formula of turning process machining parameters on carburizing heat treatment deformation; ； Step (S506): on the basis of the influence amount of turning regenerative surface residual stress, obtain the heat treatment residual stress deformation amount: ； Step (S507): heat treatment residual stress deformation correction coefficient is: ； is the amount of deformation inherent to the carburizing heat treatment process, is the heat treatment simulation residual stress deformation result; Step (S508): obtain the total deformation amount calculation formula: ； wherein is the deformation in the heat treatment simulation, is the turning surface residual stress simulation value, is the initial preparatory heat treatment surface residual stress simulation value.

4. A method of decoupling axial deformation from residual stresses generated by cutting and heat treating of a double helical gear as set forth in claim 3, characterized in that, The specific implementation process of step S1 in the method is: After the blank is quenched and tempered (101), the blank supply state is formed, and after rough turning (102), copper plating (103) is performed for carburizing protection, and after turning the copper layer on the tooth top (104), the tooth surface forming process-milling (105) is performed, and after surface carburizing and quenching (106), profile finishing (107) is performed, and finally gear grinding (108) is performed to complete the tooth profile finishing.

5. A method of decoupling axial deformation from residual stress generation by cutting and heat treating of a double helical gear as set forth in claim 4, characterized in that, The specific implementation process of step S2 in the method is: Step S2: performing workpiece heat treatment and mechanical processing simulation according to the process parameters to obtain surface residual stress data and length deformation data of the workpiece heat treatment and mechanical processing; Including the following steps: Step S201: the blank is first quenched and tempered (101), which is divided into two heat treatment processes of quenching (201) and high-temperature tempering (202), wherein the quenching temperature is (203), the high-temperature tempering temperature is (204), T (205) represents the temperature, and t (206) represents the time; the quenched and tempered simulation residual stress and deformation data are obtained by computer-aided simulation; Step S202: after the blank is quenched and tempered (101), rough turning (102) is performed, wherein the blank is (301) and the rough turning is (302); the residual stress and deformation data of the cutting simulation are obtained by computer-aided simulation; Step S203: the workpiece is surface carburized (106), which includes multiple heat treatment processes, including: carburizing process (401), quenching process (402), ice cooling process (403), first tempering process (404), and second tempering process (405); wherein the carburizing temperature is (406), the quenching temperature is (407), the ice cooling temperature is (408), and the tempering temperature is (409); the carburizing heat treatment simulation data are obtained by computer-aided simulation.

6. A method of decoupling axial deformation from residual stress generation by cutting and heat treating of double helical gears as claimed in claim 5 wherein, The specific implementation process of step S3 in the method is: Step S3: selecting high, medium and low three sets of surface stress corresponding to cutting parameter combinations according to the simulation data in step S2; Including the following steps: Step S301: According to the cutting simulation data obtained in step S202, high, medium and low three cutting parameters are designed, experimental combinations are designed, three test pieces are selected as shown in Figure 8 to form three combinations, the difference between the data of each two experimental samples is extracted, three groups of available data can be extracted, and as much experimental data as possible is extracted with the least experimental cost; Step S302: select three groups of surface stress corresponding cutting parameter combinations, design orthogonal experiment group, wherein the cutting parameters are: cutting line speed V c (501), cutting depth a p (502) and single feed f (503).

7. A method of decoupling axial deformation from residual stresses generated by cutting and heat treating of a double helical gear as set forth in claim 6, characterized in that, The specific implementation process of step S4 in the method is as follows: Step S4: Measure the surface residual stress and axial size data of the test piece; including the following steps: Step S401: Perform first surface residual stress detection after rough turning in step S101 (102); Step S402: Perform first length detection after tooth milling in step S101 (105); Step S403: Perform second length detection after carburizing heat treatment in step S101 (106); Step S404: Perform second surface residual stress detection after the second length detection in step S305.

8. A double helical gear cutting and heat treatment residual stress induced axial deformation decoupling system characterized by: The system has program modules corresponding to the steps of the method of claim 1, and when running, executes the steps in the decoupling method of the residual stress generation axial deformation of the double helical gear cutting and heat treatment, and realizes the automatic calculation of the total axial deformation of the double helical gear.

Images