High conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process

Abstract

This invention belongs to the field of new energy vehicle motor processing technology. It discloses a micro-strain controlled bending forming process for the topology adaptation of high-conductivity motor stator winding functional copper busbars. The aim is to solve the problems of difficult springback control and insufficient precision in the traditional automotive high-conductivity motor copper busbar forming process. The process includes pretreatment, bending strategy formulation, one-time rough bending pre-forming, high-frequency feedback fine bending approximation, and post-processing and traceability stages. The core adopts a rough bending followed by fine bending, combined with real-time visual inspection and closed-loop feedback control. The bending parameters are dynamically adjusted through a piecewise nonlinear compensation algorithm. A small-amplitude, high-frequency bending process is used to adapt to the topology requirements of copper busbars with multiple inflection points, variable curvature, and unequal thickness. This process does not require preset material parameters, has precise angle deviation control, and has lower residual stress than traditional processes. It significantly improves the process versatility, production changeover efficiency, and the performance and reliability of the formed copper busbars.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle motor processing technology, and in particular to a micro-strain controlled forming process for topology adaptation of high-conductivity stator winding functional copper busbars. Background Technology

[0002] High-conductivity motor stator winding functional copper busbars are core components of modern high-power-density motors, especially in main drive motors, auxiliary motors, and on-board chargers for new energy vehicles. Their forming precision and performance directly determine the overall efficiency, reliability, and service life of the motor. New energy vehicle drive motors are developing towards 800V high voltage, flat wire, high power density, and wide temperature range. Their stator windings generally adopt a hairpin-type flat wire copper busbar structure, featuring complex topological characteristics such as multiple inflection points, variable curvature, and unequal thickness overlaps. This places far more stringent requirements on forming precision, residual stress control, conductivity, and surface insulation quality than those for industrial motors.

[0003] Traditional copper busbar forming processes suffer from difficulty in controlling springback. Copper, especially high-conductivity copper, exhibits high elasticity and plasticity. During forming, springback occurs due to the release of internal stress. Traditional processes often rely on experience or pre-set material springback models for compensation. However, due to variations in copper busbar material, thickness, heat treatment state, and actual forming conditions, the uncertainty of springback is significant, making precise control of the final angle difficult, often resulting in deviations of 0.1° or even greater. In the field of new energy vehicles, this deviation can lead to uneven stator winding assembly gaps, decreased slot fill factor, and increased risk of partial discharge, subsequently causing insulation failure, motor overheating, and reduced driving range. Furthermore, the high residual stress generated by traditional processes accelerates copper busbar fatigue cracking under motor thermal cycling conditions, severely impacting the overall safety and service life of new energy vehicles. Summary of the Invention

[0004] The technical problem to be solved by this invention is that the springback amount is difficult to control precisely in the traditional copper busbar forming process. To address this, we propose a micro-strain controlled bending forming process for high conductivity motor stator winding functional copper busbar topology adaptation.

[0005] To achieve the above objectives, this application adopts the following technical solution: a micro-strain controlled bending forming process for high-conductivity motor stator winding functional copper busbar topology adaptation, including the following steps: S1. Pre-treatment stage: cleaning, stress pre-treatment, and basic data acquisition of the high-conductivity copper busbar, and completing positioning and clamping; S2. Bending strategy formulation and angle planning: based on the original size data of the copper busbar and the target bending angle, an automatic two-step bending strategy of one-time rough bending and high-frequency feedback fine bending is formulated, and the progressive gradient of the rough bending angle threshold and the amplitude and frequency of the fine bending stage is planned; S3. One-time rough bending pre-forming: driving the bending equipment to perform a single bending according to the planned rough bending angle, and confirming the angle deviation through visual inspection after completing the pre-forming; S4. High-frequency feedback fine bending approximation: through repeated small-amplitude high-frequency bending combined with real-time visual inspection feedback, the target angle is approximated step by step, forming a closed-loop control of bending, springback detection, and compensation bending, and finally completing the copper busbar bending forming.

[0006] Furthermore, the specific implementation method of the bending strategy formulation and angle planning described in S2 is as follows: S201 Data Input and Analysis: The main control system reads the original size data of the copper busbar collected by the three-dimensional laser scanning equipment and the preset target bending angle and topology parameters, and identifies the bending points, bending sequence and target angle of each point through the topology path analysis algorithm; S202. Coarse bending angle planning: Based on the formula Calculate the angle of the coarse bend endpoint, where The coarse refraction coefficient is adjusted to 80°-83° when the target angle is 90°, and to 26°-28° when the target angle is 30°. When the target angle is >30° and <90°, the coarse refraction coefficient is adjusted linearly proportionally to ensure that the deviation from the target angle after coarse refraction is 8%-12%, leaving sufficient space for fine refraction adjustment; S203. Fine refraction parameter pre-planning: Based on the exponential progressive model, the amplitude and frequency gradient of the fine refraction stage are preset, and the amplitude progression satisfies the formula ,in =0.1° is the initial amplitude. =2-3 is the amplitude attenuation coefficient. The initial deviation is for fine refraction; the frequency progression satisfies the formula. ,in The initial frequency, The frequency increment factor; the natural springback time of the copper busbar was determined using dynamic stress testing equipment. The time interval T for the lowest frequency of fine bending is set to ≥0.03s to ensure that the elastic strain of the copper busbar is fully released before each bend; S204. Visual point matching: The main control system automatically adjusts the shooting angle, focal length, and light source intensity of the CCD high-definition visual measurement system according to the coordinates of the bending point to ensure that the shooting range accurately covers the bending area, with a visual blind zone ≤0.01cm. 2 This provides a blind-spot-free measurement condition for subsequent angle detection.

[0007] Furthermore, the specific implementation method of the one-time rough bending preforming described in S3 is as follows: S301. Equipment mode switching: The main control system sends a rough bending mode command to the high-frequency reciprocating hydraulic bending machine. The bending machine completes the switching from standby mode to rough bending mode within ≤0.1s, and the hydraulic system pressure is stabilized at 15-20MPa; S302. Rough bending execution: According to the rough bending angle planned in step S202, the bending machine drives the servo feed system to perform a single bending action at a speed of 0.3-0.5mm / s, bending to the planned rough bending endpoint angle in one step. During the bending process, the hydraulic system pressure... Force fluctuation ≤ ±5% to ensure uniform bending force; after bending, the hydraulic mechanism performs a small-amplitude recovery at 10% of the rough bending angle, with a recovery speed of 0.1-0.2 mm / s, allowing the copper busbar initial elastic strain release time; S303. Rough bending detection and supplementary bending: The CCD high-definition vision measurement system starts shooting within 0.01s after the rough bending recovery is completed, identifies the copper busbar bending contour through edge extraction algorithm, and measures the deviation between the actual rough bending angle and the planned rough bending angle; when the deviation is ≤ 0.5°, the rough bending is judged to be qualified and enters the fine bending stage; when the deviation is > 0.5°, the system automatically calculates the supplementary bending amount. ,in To correct the rough bending angle deviation, drive the bending machine to perform one additional bending action, and check again after the additional bending until the deviation is ≤0.5°, ensuring that the rough bending angle falls precisely within the preset range.

[0008] Furthermore, the specific implementation method of the high-frequency feedback fine bending approximation described in S4 is as follows: S401. Fine bending mode activation: After the rough bending test is qualified, the main control system sends a fine bending mode command to the bending machine. The bending machine switches to fine bending mode within ≤0.1s, and the hydraulic recovery amount is automatically adjusted to 15%-20% of the single bending angle; S402. Gradient parameter control: Based on the angle deviation detected in real time by the CCD vision measurement system, the bending amplitude and frequency are adjusted in three gradients: when the deviation is 1°-0.5°, the single bending amplitude is 0.1°-0.05°, the bending frequency is 80-120Hz, and the time interval is 0.04-0.05s; when the deviation is 0.5°-0.1°, the single bending amplitude is 0.05°. -0.02°, bending frequency 120-150Hz, time interval 0.03-0.04s; when the deviation is ≤0.1°, the single bending amplitude is ≤0.02°, the bending frequency is maintained at 150Hz, and the time interval is 0.03s; the time interval under all gradients is greater than the natural springback time of the copper busbar of 0.015s-0.025s, ensuring that the elastic strain is fully released before each bend; S403. Closed-loop feedback control: after each bend and hydraulic recovery, the CCD high-definition vision measurement system keeps the same frequency and synchronous shooting as the bending action, that is, the shooting frequency is the same as the bending frequency, and accurately measures the angle after springback through anti-interference image processing algorithm, with a measurement accuracy of ±0.005°, and transmits the angle deviation data. The data is transmitted in real time to the main control system; the system calculates the compensation amount for the next bend based on a piecewise nonlinear compensation algorithm. Specifically: when hour, ( (Reserve rebound redundancy); when hour, ( , (to accurately correct deviations); when hour, ( (To avoid overcompensation); the system drives the bending machine to perform the next bend according to the compensation amount, iterating until the angle deviation is correct. ,in For accuracy thresholds, standard configuration High-precision configuration S404. Multi-point cyclic forming: After completing the fine bending of a single point, the main control system drives the servo motor to move the positioning fixture according to the preset path, with a positioning accuracy of ±0.01mm and a positioning time of ≤0.5s. After the positioning is completed, the process of rough bending angle planning, rough bending execution, rough bending detection, and fine bending approximation is repeated until all bending points are formed. During the forming process, the system automatically records the rough bending and fine bending parameters of each point, including frequency, single angle and recovery amount, as well as the angle deviation data and forming time of each iteration step, forming a production traceability file.

[0009] Furthermore, the algorithm's iterative convergence mechanism is as follows: A maximum number of iterations N = 50 is set. If the convergence condition is not met after reaching N iterations, then... When the system automatically alarms and starts the parameter optimization program, it adjusts the compensation coefficients k1, k2, and k3. In practical applications, the number of iterations for convergence is ≤20, and the convergence efficiency is improved by more than 30% compared with the traditional linear compensation algorithm.

[0010] Furthermore, the system has a resolution of ≥20 megapixels, a lens focal length of 16-50mm, and uses a ring-shaped LED fill light device with an adjustable brightness range of 500-3000 lux. Its anti-interference image processing algorithm can handle bending dust concentrations ≤10mg / m³. 3 It works stably in environments with light intensity variations of ±30%, and the angle measurement error fluctuation is ≤±0.001° after 1000 continuous measurements, with no measurement failures.

[0011] Furthermore, the system is equipped with an industrial-grade PLC with a CPU frequency of ≥1GHz and memory of ≥2GB, and a machine vision processing module with a response latency of ≤10ms. It supports automatic topology path planning, real-time deviation calculation, and compensation instruction output. The built-in database supports the storage and retrieval of historical bending data, including material, thickness, angle, springback, and compensation parameters. The storage capacity is ≥1TB, and the data retention period is ≥3 years, providing data support for subsequent process optimization.

[0012] Furthermore, the topology adaptation implementation method for multi-inflection point bends and variable curvature bends is as follows: Multi-inflection point bends: The bend sequence is optimized through a path planning algorithm based on the minimum strain accumulation principle. Let the inflection point coordinates be (x, y) (i=1,2,...,m), and then... use the formula... Calculate the strain influence of the bend at the j-th inflection point on the i-th inflection point, where y is the distance from the measuring point to the neutral axis. Where ρ is the micro-bending angle and ρ is the radius of curvature; the bending sequence with the smallest total strain influence is prioritized to avoid secondary strain at the formed inflection points due to subsequent bending, ensuring that the bending accuracy deviation at each inflection point is ≤ ±0.03°; variable curvature bending: through the die curvature adaptive adjustment mechanism, the curvature change data of the copper busbar bending area is collected in real time, driving the die curvature according to the formula Dynamic adjustment, among which The effective length of the bending section. The target angle at position x is used to ensure uniform strain distribution on the copper busbar surface, with a strain deviation of ≤±5%, avoiding localized stress concentration. For copper busbars with unequal thickness: For copper busbars with a thickness difference ≤2mm, the main control system automatically identifies the thickness values ​​of different areas and sets the bending force and single bending angle according to the strain control standard ε≤0.0015 for the thicker area. Simultaneously, it optimizes the amplitude gradient during the fine bending stage and the amplitude attenuation coefficient for the thicker area. Increase by 0.5 to ensure that the bending accuracy deviation in areas of different thicknesses is ≤ ±0.03°.

[0013] Furthermore, the precision control and quality indicators of the process are achieved as follows: Angle precision: Through micro-strain shaping technology and closed-loop feedback control, the deviation between the actual angle and the target angle after the copper busbar is bent is controlled within a certain range. Within the specified range, the deviation under high-precision configuration is ≤ ±0.02°; Residual stress: By adopting a micro-angle step bending and natural springback release mode, combined with low-temperature aging post-treatment, the residual stress of the copper busbar is ≤120MPa, which is more than 40% lower than that of traditional processes. This is verified by X-ray stress meter with a measurement accuracy of ±5MPa; Conductivity: During the bending process, damage to the internal structure of the copper busbar is avoided. After bending, the conductivity of the copper busbar decreases by ≤1%IACS. This is verified by eddy current conductivity meter with a detection accuracy of ≤0.1%IACS to ensure that the conductivity meets the requirements of high conductivity motors; Surface quality: Through flexible fixtures, low-friction molds, and precise positioning control, the surface of the copper busbar is free of scratches and extrusion deformation. This is verified by three-dimensional surface profilometer.

[0014] Furthermore, the process includes post-processing and quality traceability stages, specifically implemented as follows: Low-temperature aging treatment: The formed copper busbar is subjected to low-temperature aging treatment at 150-180℃ for 0.5-1 hour to further release residual stress, ensuring that the residual stress is ≤100MPa; Surface protection: Passivation treatment or coating with an insulating coating is adopted, with a coating thickness of 5-10μm. The coating adhesion is verified through a cross-cut adhesion test ≥5B, and the salt spray test verifies that the salt spray corrosion resistance time is ≥48 hours; Final inspection and verification: The dimensions and topology of the formed copper busbar are verified through a 3D laser scanning device, with dimensional deviation ≤±0.02mm and curvature deviation ≤±0.5mm; Traceability archive: The system automatically generates a complete quality report containing the copper busbar number, material type, original size data, pre-processing parameters, rough bending parameters and fine bending parameters, angle deviation records at each point, residual stress value, conductivity test results, equipment number, operator, and production time, supporting full-process traceability query.

[0015] The technical effects and advantages of this invention are as follows: 1. The bending scheme of this invention does not require preset material parameters. It adopts a closed-loop control of high-frequency feedback fine bending approximation. By real-time visual detection of the actual angle of the copper busbar after springback and dynamic calculation of the compensation amount, it eliminates the dependence on preset springback characteristic parameters such as copper busbar material and thickness. Regardless of the change of copper busbar material, it can adaptively compensate, greatly improving the versatility of the process and production changeover efficiency. 2. This invention controls the plastic deformation and stress concentration of the copper busbar within a small range during the bending process through small-amplitude high-frequency fine bending approximation. Combined with hydraulic recovery and sufficient springback time after each bend, it significantly reduces the residual stress inside the copper busbar. This allows the deviation between the actual angle and the target angle after bending to be accurately controlled within ±0.02°, which is far superior to traditional processes. At the same time, the residual stress can be greatly reduced, improving the conductivity and service life of the copper busbar. Attached Figure Description

[0016] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 This is a schematic diagram of the process flow of the present invention. Detailed Implementation

[0017] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0018] Example 1: Overall Process Flow and Core Steps As attached Figure 1 As shown, the high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process of the present invention includes the following main steps: S1. Pre-treatment stage: This stage aims to provide a clean, stress-uniform and dimensionally complete copper busbar for subsequent precision bending.

[0019] Specifically, S1 includes the following sub-steps: S101. Ultrasonic cleaning: The copper busbar is thoroughly cleaned using an ultrasonic cleaning device with a power greater than or equal to 500W. The cleaning temperature is strictly controlled between 50-60℃, and the cleaning time is 5-8 minutes to efficiently remove oil, oxide layer and impurities with a particle size greater than or equal to 0.05mm from the surface of the copper busbar. After cleaning, the surface roughness Ra of the copper busbar is checked by a laser roughness meter to ensure that it is less than or equal to 0.2μm, thus ensuring surface cleanliness and laying the foundation for subsequent visual inspection accuracy and bending fit.

[0020] S102. Stress Pretreatment: For copper busbars with residual stress greater than or equal to 250 MPa after rolling or cutting, low-temperature annealing is performed in a box-type annealing furnace. The annealing temperature is controlled at 200-250℃, held for 1-2 hours, and the cooling rate is less than or equal to 50℃ / hour. This step can reduce the residual stress of the copper busbar to less than or equal to 180 MPa, effectively reducing additional springback fluctuations and potential damage caused by residual stress during bending.

[0021] S103. Basic Data Acquisition: A three-dimensional laser scanning device with a scanning accuracy of ±0.01mm and a scanning speed of greater than or equal to 5000 points / second is used to acquire the geometric dimensions of the copper busbar with high precision, including length, width, thickness, and cross-sectional shape data. The acquisition point density is greater than or equal to 1000 points / cm. 2 This ensures the acquisition of complete copper busbar topology information. The collected data is stored in STL format, providing comprehensive data support for the accurate planning of subsequent bending angles.

[0022] S104. Positioning and Clamping: The pre-treated copper busbar is placed on a high-precision flexible positioning fixture. The positioning method employs a combination of vacuum adsorption and flexible clamping. The vacuum adsorption pressure is controlled at 0.06-0.08 MPa to ensure that the contact deviation between the adsorption surface and the copper busbar is less than or equal to 0.01 mm. The flexible clamp is made of Shore A80 polyurethane material, with a contact area greater than or equal to 80% of the copper busbar clamping area to avoid scratching the copper busbar surface and achieve a positioning accuracy of ±0.02 mm. The fixture is equipped with a displacement monitoring sensor with a resolution of less than or equal to 0.001 mm to provide real-time feedback on the clamping position deviation of the copper busbar. When the deviation is greater than or equal to ±0.03 mm, the system automatically alarms and activates the pneumatic adjustment mechanism to correct the deviation, ensuring accurate positioning before bending.

[0023] S2. Bending Strategy Formulation and Angle Planning: This stage is based on the accurate original dimensions of the copper busbar and the target bending angle, and automatically formulates a two-step bending strategy through the main control system.

[0024] Specifically, S2 is implemented as follows: S201. Data Input and Analysis: The main control system reads the original size data of the copper busbar acquired by the 3D laser scanning equipment, as well as the preset target bending angle and topology parameters. Through the topology path analysis algorithm, the system can identify all bending points, determine the optimal bending sequence, and quantify the target angle of each bending point.

[0025] S202. Coarse angle planning: Based on The coarse refraction endpoint angle is calculated. Here, η is the coarse refraction coefficient, with a value ranging from 0.88 to 0.92. When the target angle is 90°, the coarse refraction is reduced to 80°-83°; when the target angle is 30°, the coarse refraction is reduced to 26°-28°. For target angles between 30° and 90°, the coarse refraction coefficient is adjusted linearly proportionally to ensure that the deviation from the target angle after coarse refraction remains between 8% and 12%, reserving sufficient adjustment space for the subsequent fine refraction stage.

[0026] S203. Pre-planning of fine bending parameters: Based on an exponential progressive model, the amplitude and frequency gradients of the fine bending stage are pre-planned. The single bending amplitude during the fine bending stage... With frequency With deviation Dynamic adjustment to satisfy the exponential progression relationship: Where: initial amplitude Amplitude attenuation coefficient Initial frequency Frequency increase coefficient Initial deviation of precision refraction At the same time, the time interval of the fine refraction frequency. Must meet: ;in Allow sufficient time for the copper busbar to naturally spring back, ensuring adequate springback before each bend and avoiding strain buildup.

[0027] Amplitude progression satisfies the formula ,in =0.1° is the initial amplitude. =2-3 is the amplitude attenuation coefficient. This represents the initial deviation for fine refraction. The frequency progression satisfies the formula... ,in The initial frequency, This is a frequency increment factor to ensure that the closer to the target angle, the smaller the bending amplitude and the higher the frequency. The natural springback time of the copper busbar is measured using dynamic stress testing equipment. The time interval T of the lowest frequency of fine bending is set to be greater than or equal to 0.03s to ensure that the elastic strain of the copper busbar can be fully released before each bend.

[0028] S204. Visual Point Matching: The main control system automatically adjusts the shooting angle, focal length, and light source intensity of the CCD high-definition visual measurement system based on the coordinates of the bending point. This ensures that the shooting range of the CCD visual measurement system can accurately cover the bending area, with a visual blind zone of less than or equal to 0.01cm. 2 This provides comprehensive measurement conditions for subsequent angle detection.

[0029] S3. One-time rough folding preforming: In this stage, a high-frequency reciprocating hydraulic bending machine is used to quickly preform the copper busbar, and preliminary angle detection is carried out.

[0030] Specifically, the specific implementation method of S3 is as follows: S301. Equipment mode switching: The main control system sends a rough folding mode command to the high-frequency reciprocating hydraulic bending machine. The bending machine completes the switching from the standby mode to the rough folding mode within less than or equal to 0.1 s, ensuring that the pressure of the hydraulic system is stable at 15 - 20 MPa.

[0031] S302. Rough folding execution: The bending machine drives the servo feed system to perform a single bending action at a speed of 0.3 - 0.5 mm / s according to the rough folding angle planned in step S202, and folds to the planned rough folding end angle in one step. During the bending process, the pressure fluctuation of the hydraulic system is strictly controlled to be less than or equal to ±5% to ensure the uniformity of the bending force. After bending, the hydraulic mechanism makes a small recovery of 10% of the rough folding angle at a speed of 0.1 - 0.2 mm / s, providing time for the preliminary elastic strain release of the copper busbar.

[0032] S303. Rough folding detection and supplementary folding: The CCD high-definition vision measurement system starts shooting within 0.01 s after the rough folding recovery is completed. The bending profile of the copper busbar is identified through an edge extraction algorithm, and the deviation between the actual rough folding angle and the planned rough folding angle is measured. When the measured deviation is less than or equal to 0.5°, it is determined that the rough folding is qualified, and the fine folding stage can be entered. When the deviation is greater than 0.5°, the system automatically calculates the supplementary folding amount , where is the rough folding angle deviation. The system drives the bending machine to perform 1 supplementary folding action. After supplementary folding, detection is carried out again until the deviation is less than or equal to 0.5°, ensuring that the rough folding angle accurately falls within the preset range.

[0033] S4. High-frequency feedback fine folding approximation: This stage is the core of achieving ultra-high precision in this process. Through small-amplitude, high-frequency repeated bending and combined with real-time visual detection feedback, a closed-loop control is formed to gradually approximate the target angle.

[0034] Specifically, the specific implementation method of S4 is as follows: S401. Fine folding mode startup: When the rough folding detection is qualified, the main control system sends a fine folding mode command to the bending machine. The bending machine switches to the fine folding mode within less than or equal to 0.1 s. At this time, the bending frequency is 30 - 150 Hz, and the hydraulic recovery amount is automatically adjusted to 15% - 20% of the single bending angle.

[0035] S402. Gradient Parameter Adjustment: Based on the deviation between the angle detected in real time by the CCD vision measurement system and the target angle, the system dynamically adjusts the bending amplitude and frequency in three gradients: When the angle deviation is between 1° and 0.5°, the single bending amplitude is adjusted to 0.1°-0.05°, the bending frequency is set to 80-120Hz, and the time interval is 0.04-0.05s. When the angle deviation is between 0.5° and 0.1°, the single bending amplitude is adjusted to 0.05°-0.02°, the bending frequency is set to 120-150Hz, and the time interval is 0.03-0.04s.

[0036] When the angular deviation is less than or equal to 0.1°, the single bending amplitude is further reduced to less than or equal to 0.02°, the bending frequency is maintained at 150Hz, and the time interval is 0.03s. Under all gradients, the time interval is greater than the natural springback time of the copper busbar, which is typically 0.015–0.025s. This ensures that the elastic strain of the copper busbar can be fully released before each bend, avoiding the impact of strain accumulation on accuracy.

[0037] S403. Closed-loop feedback control: After each bend and hydraulic recovery, the CCD high-definition vision measurement system maintains synchronous shooting frequency with the bending action, with the shooting frequency equal to the bending frequency. An anti-interference image processing algorithm accurately measures the actual angle after springback, with a measurement accuracy of ±0.005°. The angle deviation data is transmitted to the main control system in real time, and the system calculates the compensation amount for the next bend based on a piecewise nonlinear compensation algorithm. Its core control algorithm is based on an iterative compensation model, the specific derivation of which is as follows: Let the target bending angle be... The actual springback angle after the nth bend is The angle is measured by a CCD vision system, so the angle deviation for the nth time is: Control system based on deviation Calculate the first Secondary bending compensation A piecewise nonlinear compensation strategy is adopted to adapt to the rebound characteristics of different deviation ranges: Where: compensation coefficient Large deviation range, with reserved rebound redundancy; , Precise correction within the medium deviation range; Small deviation range, avoid overcompensation.

[0038] No. The theoretical angle after the second bend is: in For the first The springback after the second bend, of which This is the rebound coefficient, which is adaptively adjusted based on real-time feedback.

[0039] The iterative convergence condition is ,in For accuracy thresholds, standard configuration High-precision configuration At this point, bending stops, forming a closed-loop control chain of bending, springback detection, and bending compensation.

[0040] This closed-loop mechanism completely eliminates the dependence on the springback characteristics of the copper busbar material. Regardless of changes in the copper busbar material, thickness, or heat treatment state, there is no need to manually adjust the process parameters. The system can adaptively compensate for springback deviations through real-time feedback, achieving one-click precise bending.

[0041] S404. Multi-point Cyclic Forming: After completing the fine bending of a single bending point, the main control system drives the servo motor to move the positioning fixture along a preset path for repositioning. The repositioning accuracy is ±0.01mm, and the repositioning time is less than or equal to 0.5s. After repositioning, the entire process of rough bending angle planning, rough bending execution, rough bending detection, and fine bending approximation is repeated until all bending points are formed. Throughout the forming process, the system automatically records the rough and fine bending parameters of each point, including frequency, single bending angle, hydraulic recovery amount, angle deviation data of each iteration step, and forming time, forming a complete production traceability file to facilitate subsequent process optimization and quality traceability.

[0042] Example 2: Key Components and Auxiliary Technical Details. This example further describes in detail the key components and their technical parameters on which the process of the present invention depends, so as to ensure the high precision and stability of the process.

[0043] CCD High-Definition Visual Measurement System: This system is the core sensor for achieving real-time feedback closed-loop control in this invention. The system resolution is greater than or equal to 20 million pixels, ensuring the ability to capture image details. The lens focal length range is 16-50mm, adaptable to the shooting needs of copper busbars of different sizes and bending areas. The light source uses a ring-shaped LED supplementary lighting device with an adjustable brightness range of 500-3000 lux, ensuring clear and uniform images under different lighting conditions. The system is equipped with an anti-interference image processing algorithm, enabling it to operate even when the dust concentration at bending points is less than or equal to 10mg / m³. 3 The system operates stably in environments with light intensity variations of ±30%, ensuring the reliability of measurement data. Verification showed that the angle measurement error fluctuation was less than or equal to ±0.001° in 1000 consecutive measurements, with no measurement failures, greatly guaranteeing the stability of the fine refraction stage.

[0044] Main Control System: This system is responsible for data processing, strategy formulation, command output, and closed-loop control. It is equipped with an industrial-grade PLC with a CPU clock speed greater than or equal to 1GHz and memory greater than or equal to 2GB, ensuring powerful data processing capabilities and fast response speed. Simultaneously, the system integrates a machine vision processing module, achieving a response latency of less than or equal to 10ms, enabling timely processing of visual data and generation of control commands. The main control system supports automatic topology path planning, with a planning time of less than or equal to 0.5s per piece, significantly improving production efficiency. Real-time deviation calculation takes less than or equal to 1ms per instance, ensuring the real-time performance of closed-loop control. Furthermore, the system's built-in database supports the storage and retrieval of historical bending data, with a storage capacity greater than or equal to 1TB and a data retention period greater than or equal to 3 years. This provides strong data support for subsequent process optimization, fault diagnosis, and quality traceability.

[0045] High-frequency reciprocating hydraulic bending machine: This bending machine is the actuator of this invention, and its configuration characteristics directly determine the bending accuracy and efficiency.

[0046] Drive system: Equipped with a high-precision servo feed system with a positioning accuracy of ±0.001mm, ensuring the accuracy of each micro-feed. The feed speed is adjustable from 0.1 to 0.5mm / s, with speed fluctuation less than or equal to ±2%, meeting the speed requirements of different stages of roughing and fine bending.

[0047] Mode switching: Supports seamless switching between coarse and fine folding modes, with a switching response time of less than or equal to 0.1s, ensuring a smooth process flow.

[0048] Angle adjustment: It has an adjustment accuracy of 0.001° for a single bending angle, which makes it possible to make small adjustments during the fine bending stage. The single angle range for coarse bending is 1°-5°, and the single angle range for fine bending is 0.1°-1°.

[0049] Hydraulic system: The hydraulic return speed is 0.1-0.5mm / s, and the return amount is automatically matched according to the bending mode. In the rough bending mode, it is 10% of the bending angle, and in the fine bending mode, it is 15%-20%, which effectively promotes the release of elastic strain. The system pressure stability accuracy is ±1%, ensuring the uniformity of bending force.

[0050] Bending dies: Made of Cr12MoV material, hardened to HRC60-62, ensuring wear resistance; titanium plating with a thickness of 2-3μm reduces the friction coefficient between the die and the copper busbar to less than or equal to 0.1, effectively preventing scratches on the copper busbar surface. The die curvature can be adaptively adjusted according to the copper busbar topology curvature, with an adjustment range of ρ=5-50mm to accommodate bending with varying curvature. The die clearance is set at 1.05-1.1 times the copper busbar thickness to further prevent scratches and extrusion deformation on the copper busbar surface.

[0051] Example 3: Topology Adaptation and Precision Control Strategy. This example focuses on illustrating the specific implementation of the present invention in dealing with complex bending topologies and achieving final precision control.

[0052] Topology adaptation implementation for multi-inflection point bends and variable curvature bends: Multi-inflection point bends: For multi-inflection point bends (number of inflection points) The process optimizes the bending sequence through a path planning algorithm, with the inflection point coordinates set as follows: ( If the bending sequence follows the principle of minimum strain accumulation: in For the first The inflection point bend is related to the first Strain influence at each inflection point Where y is the distance from the measuring point to the neutral axis, Let ρ be the micro-bending angle and ρ be the radius of curvature.

[0053] Variable curvature bending: Through a die curvature adaptive adjustment mechanism, the curvature change data of the copper busbar bending area is collected in real time, and the curvature of the bending die is driven according to the formula. Dynamic adjustment, among which The effective length of the bending section. Let x be the target angle at position x. This ensures uniform strain distribution on the copper busbar surface, with strain deviation less than or equal to ±5%, thereby avoiding localized stress concentration and potential material damage, and minimizing the decrease in conductivity. ,in This represents the original conductivity.

[0054] Unequal Thickness Copper Busbar Bending: For copper busbars with a thickness difference of less than or equal to 2mm, the main control system automatically identifies the thickness values ​​of different regions. Subsequent bending will set the bending force and single bending angle according to the strain control standard of the thicker region, with the standard being ε less than or equal to 0.0015. Simultaneously, the system will optimize the amplitude gradient during the fine bending stage, specifically the amplitude attenuation coefficient of the thicker region. Increase by 0.5 to ensure that the bending accuracy deviation in different thickness areas is less than or equal to ±0.03°.

[0055] Process precision control and quality indicator achievement methods: Angle precision: Through micro-strain shaping technology and high-frequency feedback closed-loop control, the deviation between the actual angle and the target angle after copper busbar bending is controlled within a certain range. Within the specified range. With high-precision configuration, this deviation can be less than or equal to ±0.02°.

[0056] Residual stress: By employing a micro-angle step bending and natural springback release method, combined with low-temperature aging post-treatment, the residual stress of the copper busbar is reduced to less than or equal to 120 MPa, which is more than 40% lower than that of traditional processes. X-ray stress testing verifies that the residual stress meets the requirements for high-conductivity motors.

[0057] Conductivity: During the bending process, damage to the internal structure of the copper busbar must be strictly avoided. After bending, the decrease in conductivity of the copper busbar should be less than or equal to 1% IACS. Eddy current conductivity meter is used for testing to ensure that the conductivity meets the requirements of high conductivity motors.

[0058] Surface quality: By using flexible fixtures, low-friction molds, and precise positioning control, we ensure that the copper busbar surface is free of scratches or that the scratch depth is less than or equal to 0.01 mm and the deformation is less than or equal to 0.02 mm. Excellent surface quality of the copper busbar is verified through a 3D surface profilometer.

[0059] Iterative convergence mechanism of the piecewise nonlinear compensation algorithm: This algorithm is the core of calculating the compensation quantity in closed-loop control. The algorithm sets the maximum number of iterations N=50. If the convergence condition is not met after the number of iterations reaches N, the algorithm will terminate the algorithm. When the time is right, the system automatically alarms and initiates the parameter optimization program, adjusting the compensation coefficients k1, k2, and k3. In practical applications, the number of iterations for convergence is usually less than or equal to 20, and the convergence efficiency is improved by more than 30% compared to the traditional linear compensation algorithm, ensuring the high efficiency and stability of the compensation algorithm.

[0060] Dynamic allocation of production efficiency: production efficiency (pieces / hour) and bending frequency Single bending angle Number of bending points The relationship is: Among them, total rebound , This represents the number of iterations.

[0061] When using the standard configuration ( , , , ), we can get Items / hour; employing efficient configuration ( , ), Up to 120 pieces / hour; under high-precision configuration ( , ), The output per piece per hour can be flexibly switched according to production needs.

[0062] The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A high-conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process, characterized in that, Includes the following steps: S1. Pre-processing stage: Cleaning, stress pre-treatment, and basic data acquisition are performed on the high-conductivity copper busbar, and positioning and clamping are completed; S2. Bending Strategy Formulation and Angle Planning: Based on the original dimensions of the copper busbar and the target bending angle, a two-step bending strategy of one-time rough bending and high-frequency feedback fine bending is automatically formulated, and the progressive gradient of the rough bending angle threshold and the amplitude and frequency of the fine bending stage is planned; S3. One-time Rough Bending Pre-forming: The bending equipment is driven to perform a single bend according to the planned rough bending angle. After the pre-forming is completed, the angle deviation is confirmed by visual inspection; S4. High-Frequency Feedback Fine Bending Approximation: Through repeated small-amplitude, high-frequency bending combined with real-time visual inspection feedback, the target angle is approached step by step, forming a closed-loop control of bending, springback detection, and compensation bending, and finally completing the bending and forming of the copper busbar.

2. The high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process according to claim 1, characterized in that, The specific implementation of the bending strategy formulation and angle planning described in S2 is as follows: S201 Data Input and Analysis: The main control system reads the original size data of the copper busbar collected by the three-dimensional laser scanning equipment, as well as the preset target bending angle and topology parameters, and identifies the bending points, bending sequence, and target angles at each point through the topology path parsing algorithm; S202. Coarse Bending Angle Planning: Based on the formula Calculate the angle of the coarse bend endpoint, where The coarse refraction coefficient ensures that the deviation from the target angle after coarse refraction is 8%–12%, reserving sufficient adjustment space for fine refraction; S203. Fine refraction parameter pre-planning: Based on the exponential progressive model, the amplitude and frequency gradient of the fine refraction stage are preset, and the amplitude progression satisfies the formula ,in =0.1° is the initial amplitude. =2-3 is the amplitude attenuation coefficient. This represents the initial deviation of the precision refraction. Frequency progression satisfies the formula ,in The initial frequency, The frequency increment factor; the natural springback time of the copper busbar was determined using dynamic stress testing equipment. The time interval T for the lowest frequency of fine bending is set to ≥0.03s to ensure that the elastic strain of the copper busbar is fully released before each bend; S204. Visual point matching: The main control system automatically adjusts the shooting angle, focal length, and light source intensity of the CCD high-definition visual measurement system according to the coordinates of the bending point to ensure that the shooting range accurately covers the bending area, with a visual blind zone ≤0.01cm. 2 This provides a blind-spot-free measurement condition for subsequent angle detection.

3. The high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process according to claim 1, characterized in that, The specific implementation method of the one-time rough bending preforming described in S3 is as follows: S301. Equipment mode switching: The main control system sends a rough bending mode command to the high-frequency reciprocating hydraulic bending machine. The bending machine completes the switching from standby mode to rough bending mode within ≤0.1s, and the hydraulic system pressure is stabilized at 15-20MPa; S302. Rough bending execution: According to the rough bending angle planned in step S202, the bending machine drives the servo feed system to perform a single bending action at a speed of 0.3-0.5mm / s, bending to the planned rough bending endpoint angle in one step. During the bending process, the hydraulic system pressure fluctuates. ≤±5% to ensure uniform bending force; after bending, the hydraulic mechanism performs a small-amplitude recovery at 10% of the rough bending angle, with a recovery speed of 0.1-0.2mm / s, allowing time for the copper busbar to release its initial elastic strain; S303. Rough bending detection and supplementary bending: The CCD high-definition vision measurement system starts shooting within 0.01s after the rough bending recovery is completed, identifies the copper busbar bending profile through an edge extraction algorithm, and measures the deviation between the actual rough bending angle and the planned rough bending angle; when the deviation is ≤0.5°, the rough bending is deemed qualified, and the process enters the fine bending stage; when the deviation is >0.5°, the system automatically calculates the supplementary bending amount. ,in To correct the rough bending angle deviation, drive the bending machine to perform one additional bending action, and check again after the additional bending until the deviation is ≤0.5°, ensuring that the rough bending angle falls precisely within the preset range.

4. The high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process according to claim 1, characterized in that, The specific implementation method of the high-frequency feedback fine bending approximation described in S4 is as follows: S401. Fine bending mode activation: After the rough bending test is qualified, the main control system sends a fine bending mode command to the bending machine. The bending machine switches to fine bending mode within ≤0.1s, and the hydraulic recovery amount is automatically adjusted to 15%-20% of the single bending angle; S402. Gradient parameter control: Based on the angle deviation detected in real time by the CCD vision measurement system, the bending amplitude and frequency are adjusted in three gradients: when the deviation is 1°-0.5°, the single bending amplitude is 0.1°-0.05°, the bending frequency is 80-120Hz, and the time interval is 0.04-0.05s; when the deviation is 0.5°-0.1°, The single bending amplitude is 0.05°-0.02°, the bending frequency is 120-150Hz, and the time interval is 0.03-0.04s; when the deviation is ≤0.1°, the single bending amplitude is ≤0.02°, the bending frequency remains at 150Hz, and the time interval is 0.03s; the time interval under all gradients is greater than the natural springback time of the copper busbar, ensuring that the elastic strain is fully released before each bend; S403. Closed-loop feedback control: After each bend and hydraulic recovery is completed, the CCD high-definition vision measurement system keeps the same frequency and synchronously captures images with the bending action, and accurately measures the angle after springback through anti-interference image processing algorithms, with a measurement accuracy of ±0.005°, and records the angle deviation data. The data is transmitted in real time to the main control system; the system calculates the compensation amount for the next bend based on a piecewise nonlinear compensation algorithm. Specifically: when hour, ( (Reserve rebound redundancy); when hour, ( , (to accurately correct deviations); when hour, ( (To avoid overcompensation); the system drives the bending machine to perform the next bend according to the compensation amount, iterating until the angle deviation is correct. ,in For accuracy thresholds, standard configuration High-precision configuration ; S404. Multi-point cyclic forming: After completing the fine bending of a single point, the main control system drives the servo motor to move the positioning fixture according to the preset path, with a positioning accuracy of ±0.01mm and a positioning time of ≤0.5s. After the positioning is completed, the process of rough bending angle planning, rough bending execution, rough bending detection, and fine bending approximation is repeated until all bending points are formed. During the forming process, the system automatically records the rough bending and fine bending parameters of each point, including frequency, single angle and recovery amount, as well as the angle deviation data and forming time of each iteration step, forming a production traceability file.

5. The high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process according to claim 4, characterized in that, The iterative convergence mechanism of the piecewise nonlinear compensation algorithm is as follows: Set the maximum number of iterations N = 50. If the convergence condition is not met after reaching N iterations, i.e. When the system automatically alarms and starts the parameter optimization program, it adjusts the compensation coefficients k1, k2, and k3. In practical applications, the number of iterations for convergence is ≤20, and the convergence efficiency is improved by more than 30% compared with the traditional linear compensation algorithm.

6. The high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process according to claim 4, characterized in that, This CCD high-definition visual measurement system has a resolution of ≥20 million pixels, a lens focal length of 16-50mm, and uses a ring LED supplementary lighting device. Its anti-interference image processing algorithm can handle bending dust concentrations ≤10mg / m³. 3 It works stably in environments with light intensity variations of ±30%, and the angle measurement error fluctuation is ≤±0.001° after 1000 continuous measurements, with no measurement failures.

7. The high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process according to claim 2, characterized in that, The main control system is equipped with an industrial-grade PLC and machine vision processing module, with a response latency of ≤10ms. It supports automatic topology path planning, real-time deviation calculation and compensation command output. The built-in database supports the storage and retrieval of historical bending data, with a storage capacity of ≥1TB and a data retention period of ≥3 years, providing data support for subsequent process optimization.

8. The high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process according to claim 1, characterized in that, The topology adaptation implementation for multi-inflection point bends and variable curvature bends is as follows: Multi-inflection point bends: The bend sequence is optimized using a path planning algorithm based on the minimum strain accumulation principle. Let the inflection point coordinates be (x, y) (i = 1, 2, ..., m), and then... use the formula... Calculate the strain influence of the bend at the j-th inflection point on the i-th inflection point, where y is the distance from the measuring point to the neutral axis. Where ρ is the micro-bending angle and ρ is the radius of curvature; the bending sequence with the smallest total strain influence is prioritized to avoid secondary strain at the formed inflection points due to subsequent bending, ensuring that the bending accuracy deviation at each inflection point is ≤ ±0.03°; variable curvature bending: through the die curvature adaptive adjustment mechanism, the curvature change data of the copper busbar bending area is collected in real time, driving the die curvature according to the formula Dynamic adjustment, among which The effective length of the bending section. The target angle at position x is used to ensure uniform strain distribution on the copper busbar surface, with strain deviation ≤ ±5%, thus avoiding local stress concentration. Unequal Thickness Copper Busbar Bending: For copper busbars with a thickness difference ≤2mm, the main control system automatically identifies the thickness values ​​of different areas and sets the bending force and single bending angle according to the strain control standard ε≤0.0015 for the thicker area. At the same time, it optimizes the amplitude gradient during the fine bending stage and the amplitude attenuation coefficient for the thicker area. Increase by 0.5 to ensure that the bending accuracy deviation in areas of different thicknesses is ≤ ±0.03°.

9. The high conductivity motor stator winding functional copper busbar topology adaptation micro-strain controlled bending forming process according to claim 1, characterized in that, The precision control and quality indicators of the process are achieved as follows: Angle precision: Through micro-strain shaping technology and closed-loop feedback control, the deviation between the actual angle and the target angle after the copper busbar is bent is controlled within a certain range. Within the range, the deviation under high-precision configuration is ≤ ±0.02°; residual stress: adopting the micro-angle step bending and natural springback release mode, combined with low temperature aging post-treatment, the residual stress of copper busbar is ≤120MPa, which is more than 40% lower than the traditional process, and verified by X-ray stress meter detection; Conductivity: During bending, damage to the internal structure of the copper busbar is avoided. The conductivity of the copper busbar decreases by ≤1% IACS after bending. Eddy current conductivity meter is used for testing to ensure that the conductivity meets the requirements of high conductivity motors. Surface quality: Through flexible fixtures, low-friction molds and precise positioning control, the surface of the copper busbar is free of scratches and extrusion deformation. This is verified by a three-dimensional surface profilometer.

10. The process according to claim 1, characterized in that, It also includes post-processing and quality traceability stages, specifically implemented as follows: Low-temperature aging treatment: The formed copper busbar is subjected to low-temperature aging treatment at 150-180℃ for 0.5-1 hour to further release residual stress, making the residual stress ≤100MPa; Surface protection: Passivation treatment or coating with an insulating coating is adopted, with a coating thickness of 5-10μm. The coating adhesion is verified by cross-cut adhesion test ≥5B, and the salt spray test verifies the salt spray corrosion resistance time ≥48 hours; Final inspection and verification: The dimensions and topology of the formed copper busbar are verified by three-dimensional laser scanning equipment, with dimensional deviation ≤±0.02mm and curvature deviation ≤±0.5mm; Traceability archive: The system automatically generates a complete quality report containing the copper busbar number, material model, original size data, pre-processing parameters, rough bending parameters and fine bending parameters, angle deviation records at each point, residual stress value, conductivity test results, equipment number, operator and production time, supporting full-process traceability query.

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