A copper bush lock riveting device and method

Abstract

The application belongs to the technical field of copper sleeve anti-loosening, and particularly discloses a copper sleeve anti-loosening riveting device and method. The device comprises a bottom support, a middle shaft, a mounting disc and a plurality of riveting punches. The bottom support is used for abutting against a connecting plate and a copper sleeve bottom. A positioning shaft of the middle shaft or the bottom support extends into an inner hole of the copper sleeve to form a clearance fit, so as to provide internal rigid support for the copper sleeve to prevent it from collapsing inwardly and deforming. The mounting disc abuts against the middle shaft. A plurality of riveting punches with alignment gaps are fixed on the periphery of the mounting disc in equal parts, so as to realize multi-point synchronous pressing forming. The application also discloses a matched closed-loop control method. The servo press fitting and the sensing module are used to adaptively control the pressing stroke based on a force-displacement curve slope mutation. After processing, a multi-scale deep neural network is used to integrally extract high-dimensional topographic features of riveting points for comprehensive error evaluation. The historical inertia compensation is combined to dynamically update subsequent processing parameters. The application solves the problems of uneven force and out-of-round jamming of the copper sleeve caused by traditional manual single-point knocking.

Description

Technical Field

[0001] This invention belongs to the field of copper sleeve anti-loosening technology, specifically relating to a copper sleeve anti-loosening riveting device and method. Background Technology

[0002] In the field of mechanical manufacturing and assembly, linkage mechanisms are widely used in various transmission equipment to transmit motion and power. To reduce wear on the walls of the connecting plate holes and improve the smoothness of the mechanism's operation, a copper bushing is usually press-fitted into the hinge hole of the connecting plate as a sliding bearing. The assembly quality of the connecting plate and the copper bushing directly affects the transmission accuracy and service life of the entire mechanical equipment, and is a critical link in the assembly and manufacturing process.

[0003] In traditional connecting plate assembly processes, a press is typically used to press a copper bushing into the connecting plate hole, relying on the friction generated by the interference fit between the outer wall of the copper bushing and the inner wall of the connecting plate hole to fix the bushing. To further prevent the copper bushing from shifting during subsequent use, some assembly processes involve operators using ordinary center punches and hammers to tap several indentations at a single point in the gap between the outer surface of the copper bushing and the connecting plate hole after pressing in the bushing. This causes localized deformation of the metal, generating a mechanical locking force.

[0004] However, the existing assembly process has certain limitations. First, when operators use a center punch to strike one point at a time, the impact force is concentrated on one side of the local area. This asymmetrical force state can cause the copper bushing to deform inward after being compressed, affecting the cylindricity of the inner hole of the copper bushing and causing subsequent mating shaft parts to jam. Second, the force applied by manual positioning and striking is highly random, resulting in inconsistent depths of the rivets formed on the mating surface. Under the condition that the equipment is subjected to alternating impact loads for a long time, shallower rivets cannot provide sufficient physical locking force, leaving the copper bushing with the potential risk of loosening later. Summary of the Invention

[0005] This invention addresses the problems in the prior art by providing a copper sleeve anti-loosening riveting device and method. It solves the problem in the background art where, during successive single-point hammering, the impact force is concentrated on a localized, unilateral area. This asymmetrical force state leads to the copper sleeve undergoing inward collapse deformation under pressure, affecting the cylindricity of the copper sleeve's inner hole and causing subsequent jamming of mating shafts. Simultaneously, it solves the problem that the force applied by manual positioning and hammering is highly random, resulting in inconsistent riveting depths on the mating surface. Under long-term alternating impact loads, shallower riveting points cannot provide sufficient physical locking force, leaving the copper sleeve with the potential for loosening later.

[0006] The technical solution adopted in this invention is as follows: In a first aspect, this application provides a copper sleeve anti-loosening riveting device, comprising: Bottom support component, used to abut against the bottom of the connecting plate and copper sleeve to be riveted; The bottom support is a guide seat or a pad. The guide seat includes a base and a positioning shaft extending upward from the top of the base; The pad is used to be placed in the groove of the connecting plate at the bottom of the connecting plate; The central shaft has an axial hole at the bottom. When the guide seat is used, the positioning shaft of the guide seat is inserted into the axial hole from bottom to top, and a clearance fit is formed between the positioning shaft and the axial hole. The bottom end of the central shaft can extend into the inner hole of the copper sleeve. When the bottom end of the central shaft extends into the inner hole of the copper sleeve, a clearance fit is formed between the outer wall of the central shaft and the inner wall of the copper sleeve. The central shaft includes a top for bearing downward pressure; The mounting plate has a central through hole, and the bottom end of the central shaft abuts against the upper surface of the mounting plate. The mounting plate has several mounting holes around the central through hole along the circumferential direction. Several rivet punches are fixedly installed in the several mounting holes in a corresponding manner. The rivet punches are arranged around the periphery of the central shaft along with the mounting plate. The bottom end of the rivet punch is formed with a punch tip for aligning the gap between the copper sleeve and the connecting plate.

[0007] Furthermore, the number of mounting holes and the number of riveting punches are both three; The three mounting holes are arranged in a 120° interval around the axis of the central through hole.

[0008] Furthermore, a limiting step is provided on the outer wall of the central shaft to limit the pressing depth.

[0009] Furthermore, the copper sleeve anti-loosening riveting device also includes: A servo press-fit module, connected to the top of the central shaft, is used to apply a dynamically adjustable downward press-fit force to the central shaft; The sensing module includes a force sensor for monitoring the magnitude of the downward pressure and a displacement sensor for monitoring the depth of the downward pressure.

[0010] Furthermore, the copper sleeve anti-loosening riveting device also includes: The visual inspection module is used to acquire the morphological image of the formed riveting point after the mounting plate is removed; The closed-loop control system is communicatively connected to the servo pressing module, the sensing module, and the vision inspection module, respectively. The closed-loop control system is configured to control the pressing stroke of the servo pressing module based on the slope change of the force-displacement curve fed back by the sensing module during the pressing process. After pressing is completed, the pressing force parameters in subsequent processing are updated based on the error between the morphology image obtained by the vision inspection module and the standard features.

[0011] Secondly, this application provides a method for anti-loosening riveting of copper sleeves, using the anti-loosening riveting device for copper sleeves as described in the first aspect, the method comprising the following steps: Step S1: Place the bottom support member against the bottom of the connecting plate to be riveted and the copper sleeve; Step S2: Place the mounting plate equipped with a plurality of the riveting punches at the designated riveting station, with each punch tip corresponding to the gap between the copper sleeve and the connecting plate. Step S3: Install the central shaft, with the bottom end of the central shaft abutting against the upper surface of the mounting plate; Step S4: Apply downward pressing force to the top of the central shaft to drive the punch into the gap, causing local plastic flow and mutual compression of the material at the joint between the copper sleeve and the connecting plate, forming an anti-loosening rivet point, and completing the riveting.

[0012] Furthermore, step S4 specifically includes: The servo pressing module is controlled to descend at a first speed. When the downward pressure detected by the force sensor reaches a preset contact threshold, the pressing is paused. The punch forms a tiny indentation at the gap to release the assembly gap and complete the verticality self-alignment of the tooling. The servo press module is controlled to apply the main press force, and the pressing force and pressing depth are collected to generate a force-displacement curve. When the slope of the force-displacement curve undergoes a characteristic abrupt change in plastic flow and the pressing depth reaches the target set value, the force application is stopped and the pressure is maintained.

[0013] Furthermore, step S4 also includes a step of extracting overall morphological features based on a deep neural network: Remove the central shaft and the mounting plate, and obtain the initial two-dimensional shape image of the forming riveting point through the vision inspection module; After preprocessing the initial two-dimensional topography image, the closed-loop control system inputs the preprocessed two-dimensional topography image into a pre-trained multi-scale deep neural network model. The multi-scale deep neural network model performs nonlinear mapping on the spatial morphology of the forming riveting point after local plastic flow, and extracts a high-dimensional morphology feature vector in the latent space, which includes the riveting point depth distribution law, opening area contour and radial overflow boundary features of copper material. The closed-loop control system compares the extracted high-dimensional morphological feature vector with preset standard features to determine the current riveting forming quality and generate an error evaluation result. Based on the error assessment results, the closed-loop control system adaptively updates the plastic flow slope determination parameters of the subsequent workpieces to be processed during the dynamic adaptive riveting stage.

[0014] Furthermore, the extracted high-dimensional morphological feature vector is compared with preset standard features to determine the current riveting quality and generate an error assessment result, including: The closed-loop control system has a pre-built standard feature space with qualified rivet point shapes. The closed-loop control system uses a dynamic adaptive topography evaluation function to calculate the comprehensive error of the high-dimensional topography feature vector, and the comprehensive topography deviation index of the dynamic adaptive topography evaluation function is... The formula is:

[0015] Where X is the actual extracted high-dimensional morphological feature vector. These are ideal feature vectors in the standard feature space; is the dynamic covariance matrix of the historical qualified sample distribution; N is the total number of rivet points generated in a single riveting operation; and These are the local dimension-reduced sub-features of the actual feature vector and the ideal feature vector in the i-th riveting point region, respectively; The spatial penalty weight is preset for the i-th rivet point based on the main force direction of the connecting plate; This is the local extremum amplification factor; A balance factor for dynamically adjusting the ratio of global distribution to local deviation; When the calculated comprehensive morphology deviation index If the deviation exceeds the set tolerance threshold, it is determined that there is a process deviation in the current riveting process, and the comprehensive morphology deviation index is used as the error assessment result.

[0016] Furthermore, the adaptive update of the plastic flow slope determination parameters for subsequent workpieces during the dynamic adaptive riveting stage includes: The closed-loop control system extracts the instantaneous gradient of the comprehensive morphology deviation index and introduces a historical inertial compensation term for machining vibration and material batch drift for correction. The adaptive momentum compensation update formula for the plastic flow slope determination parameter is as follows:

[0017] in, The updated plastic flow slope determination parameter for the next processing cycle; The slope parameter for determining the current processing cycle; The learning rate that the system dynamically matches based on the current deviation magnitude; This is a visual confidence matrix extracted based on ambient lighting and image sharpness from the visual detection module; Represents the Hadamard product operation; H represents the gradient of the partial derivative of the comprehensive morphology deviation index with respect to the current parameters; H is the set historical tracing time window step size. The time decay memory coefficient; For the front Historical update count of parameters for the period; and These are the coupling weight coefficients for instantaneous gradient and historical momentum compensation, respectively.

[0018] As can be seen from the above technical solutions, the advantages of the present invention are: By setting up a bottom support, central shaft, mounting plate, and several rivet punches, it is possible to achieve multi-point constraint and positioning of the gap between the copper sleeve and the connecting plate while bearing axial impact force, which can guide the material to produce plastic flow and improve the interlocking and fixing effect.

[0019] By limiting the number of mounting holes and riveting punches to three and arranging them in a 120° interval around the axis, a balanced distribution of the riveting punch working load in the circumferential direction is achieved. This enables multi-point riveting forming to be completed simultaneously in a single operation, reducing the risk of tilting caused by asymmetrical forces.

[0020] By protruding a limiting step on the outer wall of the central shaft to restrict the pressing depth, rigid mechanical limiting control in the machining depth direction is achieved, which can prevent the punch tip from being excessively pressed into the interface between the connecting plate and the copper sleeve, and reduce the risk of deformation and out-of-roundness of the inner hole of the copper sleeve.

[0021] By introducing a servo press-fit module and a sensor module for monitoring pressure and displacement, real-time digital acquisition of the physical state parameters of the entire riveting process is achieved, providing continuous force-displacement curve data stream support for forming determination.

[0022] By adding a vision inspection module to the basic structure and communicating with a closed-loop control system with dual control strategies, multi-level control based on curve slope adjustment during processing and image quality correction parameters after processing is achieved, which can eliminate quality fluctuations in multiple batches of continuous processing.

[0023] By controlling the servo press-fit module to pause based on the contact threshold after low-speed pre-tightening, then applying the main pressure and monitoring the sudden change in the curve slope characteristics, the physical elimination of assembly cumulative tolerances and the acquisition of the inflection point of material plastic yield are achieved, ensuring the tooling is vertically aligned and controlling the pressing depth.

[0024] By inputting the two-dimensional topography image into a multi-scale deep neural network model for nonlinear feature mapping after the tooling is unloaded, high-dimensional topography feature vectors can be extracted from geometric edges and deep texture semantics in the latent space.

[0025] By introducing an adaptive morphology evaluation function that integrates global Mahalanobis distance deviation, local morphology extremum sensitivity, and spatial penalty weights in the principal force direction into the evaluation loop, quantitative calculation of the comprehensive deviation index of the extracted feature vector is realized, which can obtain process execution defects and output deviation results.

[0026] By extracting the instantaneous gradient of the deviation index and dynamically updating it in conjunction with the historical momentum compensation term, which includes the environmental confidence matrix and the time decay memory coefficient, iterative correction of the plastic flow slope determination parameter is achieved, which can reduce signal oscillations caused by mechanical vibration and operating condition drift. Attached Figure Description

[0027] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the riveting of the inner surface of the connecting plate hole in the copper sleeve anti-loosening riveting device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the riveting of the outer surface of the connecting plate hole in the copper sleeve anti-loosening riveting device according to an embodiment of the present invention; Figure 3 This is a flowchart of the copper sleeve anti-loosening riveting method according to an embodiment of the present invention.

[0029] In the diagram: 1. Central shaft; 2. Copper sleeve; 3. Guide seat; 4. Mounting plate; 5. Riveting punch; 6. Connecting plate; 7. Pad block. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figure 1 and Figure 2 As shown, this application provides a copper sleeve anti-loosening riveting device, comprising: Bottom support, used to abut against the bottom of the connecting plate to be riveted and the copper sleeve 2; The bottom support component is either a guide seat 3 or a pad block 6 connected to a plate; 7. The guide seat 3 includes a base and a positioning shaft extending upward from the top of the base; The pad block 6 is connected to the plate; 7 is used to be placed in the groove of the connecting plate at the bottom of the connecting plate; The central shaft 1 has an axial hole at the bottom. When the guide seat 3 is used, the positioning shaft of the guide seat 3 is inserted into the axial hole from bottom to top, and a clearance fit is formed between the positioning shaft and the axial hole. The bottom end of the central shaft 1 can extend into the inner hole of the copper sleeve 2. When the bottom end of the central shaft 1 extends into the inner hole of the copper sleeve 2, a clearance fit is formed between the outer wall of the central shaft 1 and the inner wall of the copper sleeve 2. The central shaft 1 includes a top for bearing downward pressure; Mounting plate 4 has a central through hole, and the bottom end of the central shaft 1 abuts against the upper surface of mounting plate 4; The mounting plate 4 has several mounting holes around the central through hole along the circumferential direction. A number of rivet punches 5 are fixedly installed in the number of mounting holes in a corresponding manner. The rivet punches 5 are arranged around the periphery of the central shaft 1 along with the mounting plate 4. The bottom end of the rivet punches 5 is formed with a punch tip for aligning the gap between the copper sleeve 2 and the connecting plate.

[0032] In practice, the device can switch between two configurations, inner surface riveting 5 and outer surface riveting 5, depending on the different processing surfaces of the connecting plate.

[0033] When used for riveting the inner surface of a connecting plate, two copper sleeves 2 are typically pressed into the hole of the connecting plate to be processed. These are an upper copper sleeve 2 and a lower copper sleeve 2 arranged axially opposite each other. A certain gap is left between the axial end faces of the two copper sleeves 2 inside the connecting plate hole. At this time, the mounting plate 4 is placed in the cavity between the upper and lower copper sleeves 2 inside the connecting plate assembly. The guide seat 3, as a bottom support, is placed at the bottom. Its positioning shaft passes through the inner hole of the lower copper sleeve 2 and the central through hole of the mounting plate 4 from bottom to top, and finally inserts into the axial hole at the bottom of the central shaft 1. 1. Passing from top to bottom through the inner hole of the upper copper sleeve 2, so that its bottom end abuts against the upper surface of the mounting plate 4. Since the positioning shaft and the inner hole of the lower copper sleeve 2, and the outer wall of the central shaft 1 and the inner hole of the upper copper sleeve 2 maintain a tight clearance fit, the internal cavities of the upper and lower copper sleeves 2 are filled with rigid metal shafts during riveting. When the pressing load is transmitted downward through the central shaft 1 to the mounting plate 4 and the riveting punch 5, the metal at the mating surface deforms. The inner side of the copper sleeve 2 cannot collapse inward due to the strong support of the positioning shaft and the central shaft 1, thus effectively ensuring the cylindricity of the inner hole of the copper sleeve 2.

[0034] When used for riveting on the outer surface 5, the mounting plate 4 is placed directly on the top of the connecting plate assembly. At this time, the pad block 6 is selected to connect the plate; 7 is inserted into the connecting plate groove as a bottom support to bear and absorb axial impact force, and to prevent the connecting rod structure wall from bending and deforming under unidirectional heavy load.

[0035] In some embodiments, the number of mounting holes and the number of riveting punches 5 are both three; The three mounting holes are arranged in a 120° interval around the axis of the central through hole.

[0036] In practice, the three mounting holes and the corresponding three riveting punches 5 are distributed on a circumference concentric with the central shaft 1. When the downward pressing force is applied to the central shaft 1 and transmitted to the mounting plate 4, the load is evenly distributed into three vertical components, which act synchronously on the three riveting punches 5. This eliminates the tilting moment that is easily caused by unilateral force and maintains the stability of the vertical downward movement of each component of the tooling. The tips of the three riveting punches 5 simultaneously penetrate into the gap between the copper sleeve 2 and the connecting plate, forcing the material around the joint to flow and squeeze synchronously, forming three anti-loosening rivets in one go, improving processing efficiency and avoiding the eccentricity or uneven deformation of the copper sleeve 2 axis caused by striking point by point.

[0037] In some embodiments, a limiting step for limiting the pressing depth is provided on the outer wall of the central shaft 1.

[0038] In practice, the limiting step is an annular boss structure integrally formed on the outer wall of the middle section of the central shaft 1. Under the riveting condition of the inner surface 5, as the central shaft 1 drives the mounting plate 4 and the riveting punch 5 to move axially downwards, the punch tip gradually presses into the gap and damages the local structure. When the punch tip reaches the set reasonable damage depth, the lower end face of the limiting step rigidly abuts against the upper surface of the connecting plate, restricting the central shaft 1 from further downward displacement, limiting the pressing depth of the riveting punch 5, and preventing excessive damage to the components due to excessive operating force.

[0039] In some embodiments, the copper sleeve anti-loosening riveting device further includes: A servo press-fit module, connected to the top of the central shaft 1, is used to apply a dynamically adjustable downward press-fit force to the central shaft 1; The sensing module includes a force sensor for monitoring the magnitude of the downward pressure and a displacement sensor for monitoring the depth of the downward pressure.

[0040] In practical implementation, the servo press-fit module mainly adopts a variable-control servo motor-driven transmission screw assembly, whose output end is rigidly connected to the top of the central shaft 1, and can output continuously adjustable axial pressure according to control commands. The force sensor in the sensing module is connected in series between the servo output end and the central shaft 1 to capture the current changes in axial press-fit resistance in real time; the displacement sensor is installed on the side of the equipment guide rail or the moving slider to monitor the vertical displacement of the central shaft 1 relative to the connecting plate reference surface in real time. The closed-loop control system synchronously reads the data from the force sensor and displacement sensor at a high sampling rate during processing, and plots a complete force-displacement characteristic curve in real time within the digital control domain.

[0041] In some embodiments, the copper sleeve anti-loosening riveting device further includes: The visual inspection module is used to acquire the morphological image of the formed riveting point after the mounting plate 4 is removed; The closed-loop control system is communicatively connected to the servo pressing module, the sensing module, and the vision inspection module, respectively. The closed-loop control system is configured to control the pressing stroke of the servo pressing module based on the slope change of the force-displacement curve fed back by the sensing module during the pressing process. After pressing is completed, the pressing force parameters in subsequent processing are updated based on the error between the morphology image obtained by the vision inspection module and the standard features.

[0042] In practical implementation, the closed-loop control system achieves fully automatic closed-loop control based on a two-stage adaptive press-fitting strategy and a post-visual self-learning algorithm. During the pre-tightening positioning stage at the start of press-fitting, the system drives the servo press-fitting module to control the central shaft 1 to descend slowly at a low initial speed. When the downward pressure fed back by the force sensor reaches the set contact threshold, the system controls the equipment to pause pressing. At this time, the tips of the three riveting punches 5 have pressed a certain indentation at the joint between the copper sleeve 2 and the connecting plate. Through multi-point synchronous force application, the fitting gap between the tooling components can be automatically released, allowing the positioning shaft of the central shaft 1 and the bottom guide seat 3 to adaptively adjust to an accurate positioning state, completing the tooling alignment. Subsequently, the system enters the dynamic adaptive riveting stage, controlling the servo press-fitting module to apply the main press-fitting force and continuously calculating the derivative slope of the real-time force-displacement curve. When the system detects a sudden change in the curve slope, it indicates that the softer copper material has reached the plastic yield inflection point and begins to be squeezed and flowed into the local depressions on the inner wall of the connecting plate, forming a mechanical interlock. At this point, the system combines the target displacement increment to control the stroke, and holds pressure after reaching the endpoint to eliminate the elastic rebound of the metal material. After the pressing stroke ends and the tooling is removed, the industrial camera in the vision inspection module captures the initial two-dimensional shape image of the formed rivet and inputs it into the multi-scale deep neural network model in the controller. This network extracts a high-dimensional feature vector containing the rivet depth, opening area, and radial material overflow boundary through latent space feature mapping. The control system calls the adaptive shape evaluation function, and calculates the comprehensive shape deviation index between the actual feature and the standard ideal space by combining the global Mahalanobis distribution deviation of the feature, the sensitivity of local shape extrema, and the spatial penalty weight of the main force direction. If the deviation index exceeds the tolerance, it indicates that there is a process drift caused by the hardness fluctuation of the workpiece batch or the vibration of machining. The system will start the gradient descent optimization strategy and superimpose historical time momentum compensation to automatically correct and update the pre-tightening contact threshold and yield slope judgment parameters in the next processing cycle.

[0043] Please see Figure 3 As shown, this application provides a method for anti-loosening riveting of copper sleeves, using the aforementioned anti-loosening riveting device. The method includes the following steps: Step S1: Place the bottom support member against the bottom of the connecting plate to be riveted and the bottom of the copper sleeve 2; Step S2: Place the mounting plate 4, which is equipped with a plurality of the riveting punches 5, in the set riveting station, with each punch tip corresponding to the gap between the copper sleeve 2 and the connecting plate. Step S3: Install the central shaft 1, with the bottom end of the central shaft 1 abutting against the upper surface of the mounting plate 4; Step S4: Apply downward pressing force to the top of the central shaft 1 to drive the punch into the gap, causing local plastic flow and mutual compression of the material at the joint between the copper sleeve 2 and the connecting plate, forming anti-loosening rivet points, and completing the riveting.

[0044] In some embodiments, step S4 specifically includes: The servo pressing module is controlled to descend at a first speed. When the downward pressure detected by the force sensor reaches a preset contact threshold, the pressing is paused. The punch forms a tiny indentation at the gap to release the assembly gap and complete the verticality self-alignment of the tooling. The servo press module is controlled to apply the main press force, and the pressing force and pressing depth are collected to generate a force-displacement curve. When the slope of the force-displacement curve undergoes a characteristic abrupt change in plastic flow and the pressing depth reaches the target set value, the force application is stopped and the pressure is maintained.

[0045] In some embodiments, step S4 further includes a holistic morphological feature extraction step based on a deep neural network: Remove the central shaft 1 and the mounting plate 4, and obtain the initial two-dimensional shape image of the forming riveting point through the vision detection module; After preprocessing the initial two-dimensional topography image, the closed-loop control system inputs the preprocessed two-dimensional topography image into a pre-trained multi-scale deep neural network model. The multi-scale deep neural network model performs nonlinear mapping on the spatial morphology of the forming riveting point after local plastic flow, and extracts a high-dimensional morphology feature vector in the latent space, which includes the riveting point depth distribution law, opening area contour and radial overflow boundary features of copper material. The closed-loop control system compares the extracted high-dimensional morphological feature vector with preset standard features to determine the current riveting forming quality and generate an error evaluation result. Based on the error assessment results, the closed-loop control system adaptively updates the plastic flow slope determination parameters of the subsequent workpieces to be processed during the dynamic adaptive riveting stage.

[0046] In practical implementation, after the pressing mechanism is reset, the vision inspection module uses an industrial camera to capture the area containing the joint between the copper sleeve 2 and the connecting plate. The closed-loop control system first preprocesses the initial two-dimensional topography image, including grayscale conversion, median filtering for noise reduction, and edge detection-based cropping of the rivet point area. The preprocessed image is then processed by a multi-scale deep neural network model. The shallow layer of the multi-scale deep neural network model obtains the geometric edge contours of the rivet points, while the deep layer extracts the semantic information of texture and copper material overflow. Through nonlinear mapping of the latent space, discrete pixel information is fused into a high-dimensional topography feature vector. Subsequently, the extracted results are used as a data benchmark, and the control loop completes the forming quality evaluation and iterative iteration of process parameters for the next cycle.

[0047] In some embodiments, comparing the extracted high-dimensional morphological feature vector with preset standard features to determine the current riveting quality and generate an error evaluation result includes: The closed-loop control system has a pre-built standard feature space with qualified rivet point shapes. The closed-loop control system uses a dynamic adaptive topography evaluation function to calculate the comprehensive error of the high-dimensional topography feature vector, and the comprehensive topography deviation index of the dynamic adaptive topography evaluation function is... The formula is:

[0048] Where X is the actual extracted high-dimensional morphological feature vector. These are ideal feature vectors in the standard feature space; is the dynamic covariance matrix of the historical qualified sample distribution; N is the total number of rivet points generated in a single riveting operation; and These are the local dimension-reduced sub-features of the actual feature vector and the ideal feature vector in the i-th riveting point region, respectively; The spatial penalty weight is preset for the i-th rivet point based on the main force direction of the connecting plate 6; This is the local extremum amplification factor; A balance factor for dynamically adjusting the ratio of global distribution to local deviation; When the calculated comprehensive morphology deviation index If the deviation exceeds the set tolerance threshold, it is determined that there is a process deviation in the current riveting process, and the comprehensive morphology deviation index is used as the error assessment result.

[0049] In practice, the comprehensive morphology deviation index is used to quantify the physical deviation between the actual processing result and the ideal state. All coefficients and parameters in the formula are obtained through engineering statistics and calibration.

[0050] Among them, the dynamic covariance matrix of the historical qualified sample distribution The acquisition method is as follows: during the initial equipment adjustment phase, a set of calibration component images that have passed physical destructive testing is collected, high-dimensional features are extracted and mathematical statistical calculations are performed to generate the data, and the data is updated with moving weights as new qualified batches are added during subsequent operation; based on the preset first main force direction of the connecting plate 6... Spatial penalty weight for each rivet point The weighting factor is set based on the finite element stress analysis results of the connecting plate 6 structure to be processed. If the location of the rivet point coincides with the axis of the main drive load of the connecting plate 6, a higher weighting value (e.g., 1.2-1.5) is assigned, while rivets in non-main load directions are assigned a lower weighting value (e.g., 0.5-0.8), thus reflecting the different effects of rivet points at different locations on the overall anti-loosening performance; local extremum amplification factor. The default value is a constant greater than 1, and a dynamic adjustment balance factor is also included. The default value is a constant between 0 and 1. and The tolerances were determined by process technicians based on the assembly tolerances of the copper sleeve 2 of a specific specification, using orthogonal experimental data.

[0051] In some embodiments, adaptively updating the plastic flow slope determination parameter of the subsequent workpiece to be processed during the dynamic adaptive riveting stage includes: The closed-loop control system extracts the instantaneous gradient of the comprehensive morphology deviation index and introduces a historical inertial compensation term for machining vibration and material batch drift for correction. The adaptive momentum compensation update formula for the plastic flow slope determination parameter is as follows:

[0052] in, The updated plastic flow slope determination parameter for the next processing cycle; The slope parameter for determining the current processing cycle; The learning rate that the system dynamically matches based on the current deviation magnitude; This is a visual confidence matrix extracted based on ambient lighting and image sharpness from the visual detection module; Represents the Hadamard product operation; H represents the gradient of the partial derivative of the comprehensive morphology deviation index with respect to the current parameters; H is the set historical tracing time window step size. The time decay memory coefficient; For the front Historical update count of parameters for the period; and These are the coupling weight coefficients for instantaneous gradient and historical momentum compensation, respectively.

[0053] In practice, the parameter update mechanism not only corrects the process deviation of a single processing operation, but also filters out parameter oscillations caused by accidental working conditions such as metal debris interference through time series inertia compensation.

[0054] The system dynamically adjusts the learning rate based on the current deviation magnitude. The confidence matrix is ​​obtained by querying a built-in step-type control function. A larger shape deviation results in a higher learning rate to accelerate convergence, but a safety upper limit threshold is set. The matrix is ​​generated by the vision system by calculating the global information entropy and local contrast of the current image. When overexposure of ambient light or partial occlusion of the lens by oil stains is detected, the value of the corresponding region of this matrix will approach 0, thereby actively suppressing the update amplitude of the current parameters through Hadamard product operation. The historical traceability time window step size H is determined by the steady-state processing cycle of the equipment, and is usually configured to be 5 to 10 cycles. Time decay memory coefficient. A calibration constant between 0.7 and 0.9 is used to ensure that the influence of processed samples further back in time on the current compensation decays exponentially. The coupling weight coefficients for instantaneous gradient and historical momentum compensation are also used. and satisfy The relationship is set by the commissioning personnel based on the deviation convergence curve during the equipment trial operation phase.

[0055] The above description is merely a preferred embodiment of one or more embodiments of this specification and is not intended to limit the scope of one or more embodiments of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the protection scope of one or more embodiments of this specification.

Claims

1. A copper sleeve anti-loosening riveting device, characterized in that, include: Bottom support component, used to abut against the bottom of the connecting plate and copper sleeve to be riveted; The bottom support is a guide seat or a pad. The guide seat includes a base and a positioning shaft extending upward from the top of the base; The pad is used to be placed in the groove of the connecting plate at the bottom of the connecting plate; The central shaft has an axial hole at the bottom. When the guide seat is used, the positioning shaft of the guide seat is inserted into the axial hole from bottom to top, and a clearance fit is formed between the positioning shaft and the axial hole. The bottom end of the central shaft can extend into the inner hole of the copper sleeve. When the bottom end of the central shaft extends into the inner hole of the copper sleeve, a clearance fit is formed between the outer wall of the central shaft and the inner wall of the copper sleeve. The central shaft includes a top for bearing downward pressure; The mounting plate has a central through hole, and the bottom end of the central shaft abuts against the upper surface of the mounting plate. The mounting plate has several mounting holes around the central through hole along the circumferential direction. Several rivet punches are fixedly installed in the several mounting holes in a corresponding manner. The rivet punches are arranged around the periphery of the central shaft along with the mounting plate. The bottom end of the rivet punch is formed with a punch tip for aligning the gap between the copper sleeve and the connecting plate.

2. The copper sleeve anti-loosening riveting device according to claim 1, characterized in that, The number of mounting holes and the number of riveting punches are both three; The three mounting holes are arranged in a 120° interval around the axis of the central through hole.

3. The copper sleeve anti-loosening riveting device according to claim 1, characterized in that, The outer wall of the central shaft is provided with a limiting step to restrict the depth of downward pressure.

4. The copper sleeve anti-loosening riveting device according to claim 1, characterized in that, The copper sleeve anti-loosening riveting device also includes: A servo press-fit module, connected to the top of the central shaft, is used to apply a dynamically adjustable downward press-fit force to the central shaft; The sensing module includes a force sensor for monitoring the magnitude of the downward pressure and a displacement sensor for monitoring the depth of the downward pressure.

5. The copper sleeve anti-loosening riveting device according to claim 4, characterized in that, The copper sleeve anti-loosening riveting device also includes: The visual inspection module is used to acquire the morphological image of the formed riveting point after the mounting plate is removed; The closed-loop control system is communicatively connected to the servo pressing module, the sensing module, and the vision inspection module, respectively. The closed-loop control system is configured to control the pressing stroke of the servo pressing module based on the slope change of the force-displacement curve fed back by the sensing module during the pressing process. After pressing is completed, the pressing force parameters in subsequent processing are updated based on the error between the morphology image obtained by the vision inspection module and the standard features.

6. A method for preventing loosening of copper sleeves through riveting, using the anti-loosening riveting device for copper sleeves as described in claim 5, characterized in that, Includes the following steps: Step S1: Place the bottom support member against the bottom of the connecting plate to be riveted and the copper sleeve; Step S2: Place the mounting plate equipped with a plurality of the riveting punches at the designated riveting station, with each punch tip corresponding to the gap between the copper sleeve and the connecting plate. Step S3: Install the central shaft, with the bottom end of the central shaft abutting against the upper surface of the mounting plate; Step S4: Apply downward pressing force to the top of the central shaft to drive the punch into the gap, causing local plastic flow and mutual compression of the material at the joint between the copper sleeve and the connecting plate, forming an anti-loosening rivet point, and completing the riveting.

7. The method for preventing loosening of copper sleeves by riveting according to claim 6, characterized in that, Step S4 specifically includes: The servo pressing module is controlled to descend at a first speed. When the downward pressure detected by the force sensor reaches a preset contact threshold, the pressing is paused. The punch forms a tiny indentation at the gap to release the assembly gap and complete the verticality self-alignment of the tooling. The servo press module is controlled to apply the main press force, and the pressing force and pressing depth are collected to generate a force-displacement curve. When the slope of the force-displacement curve undergoes a characteristic abrupt change in plastic flow and the pressing depth reaches the target set value, the force application is stopped and the pressure is maintained.

8. The method for preventing loosening of copper sleeves by riveting according to claim 7, characterized in that, Step S4 also includes a step of overall morphological feature extraction based on deep neural networks: Remove the central shaft and the mounting plate, and obtain the initial two-dimensional shape image of the forming riveting point through the vision inspection module; After preprocessing the initial two-dimensional topography image, the closed-loop control system inputs the preprocessed two-dimensional topography image into a pre-trained multi-scale deep neural network model. The multi-scale deep neural network model performs nonlinear mapping on the spatial morphology of the forming riveting point after local plastic flow, and extracts a high-dimensional morphology feature vector in the latent space, which includes the riveting point depth distribution law, opening area contour and radial overflow boundary features of copper material. The closed-loop control system compares the extracted high-dimensional morphological feature vector with preset standard features to determine the current riveting forming quality and generate an error evaluation result. Based on the error assessment results, the closed-loop control system adaptively updates the plastic flow slope determination parameters of the subsequent workpieces to be processed during the dynamic adaptive riveting stage.

9. The method for preventing loosening of copper sleeves by riveting according to claim 8, characterized in that, The extracted high-dimensional morphological feature vector is compared with preset standard features to determine the current riveting quality and generate an error evaluation result, including: The closed-loop control system has a pre-built standard feature space with qualified rivet point shapes. The closed-loop control system employs a dynamic adaptive topography evaluation function to calculate the comprehensive error of the high-dimensional topography feature vector. The comprehensive topography deviation index of the dynamic adaptive topography evaluation function... The formula is: Where X is the actual extracted high-dimensional morphological feature vector. These are ideal feature vectors in the standard feature space; is the dynamic covariance matrix of the historical qualified sample distribution; N is the total number of rivet points generated in a single riveting operation; and These are the local dimension-reduced sub-features of the actual feature vector and the ideal feature vector in the i-th riveting point region, respectively; The spatial penalty weight is preset for the i-th rivet point based on the main force direction of the connecting plate; This is the local extremum amplification factor; A balance factor for dynamically adjusting the ratio of global distribution to local deviation; When the calculated comprehensive morphology deviation index If the deviation exceeds the set tolerance threshold, it is determined that there is a process deviation in the current riveting process, and the comprehensive morphology deviation index is used as the error assessment result.

10. The method for preventing loosening of copper sleeves by riveting according to claim 9, characterized in that, The adaptive updating of the plastic flow slope determination parameters for subsequent workpieces during the dynamic adaptive riveting stage includes: The closed-loop control system extracts the instantaneous gradient of the comprehensive morphology deviation index and introduces a historical inertial compensation term for machining vibration and material batch drift for correction. The adaptive momentum compensation update formula for the plastic flow slope determination parameter is as follows: in, This is used as a parameter to determine the plastic flow slope for the next processing cycle after the update. The slope parameter for determining the current processing cycle; The learning rate that the system dynamically matches based on the current deviation magnitude; This is a visual confidence matrix extracted based on ambient lighting and image sharpness from the visual detection module; Represents the Hadamard product operation; H represents the gradient of the partial derivative of the comprehensive morphology deviation index with respect to the current parameters; H is the set historical tracing time window step size. The time decay memory coefficient; For the front Historical update count of parameters for the period; and These are the coupling weight coefficients for instantaneous gradient and historical momentum compensation, respectively.

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