Automobile rear end adjusting method

Abstract

The invention discloses a method for adjusting the rear end of an automobile, and relates to the technical field of automobile manufacturing, and the method comprises the following steps: firstly, carrying out reference position coarse adjustment on a back door of an automobile body in white by utilizing a penetrating type assembling and adjusting assistive device and an adjustable hinge; secondly, a vehicle body side wall outline is scanned to establish a follow-up coordinate system, and a high-precision reference positioning hole of a side wall tail lamp is generated through online punching; then, the final closing position of the back door is determined based on the standardized lock catch position; then, the installed side wall tail lamp is used as a fixing reference, and the exposed adjusting structure is used for conducting fine adjustment and alignment on the back door lamp; and finally, carrying out compensatory adjustment on the rear bumper to enable the rear bumper to be matched with the adjusted peripheral parts. According to the method, the problem of tolerance accumulation is effectively solved by decomposing the dimension chain, creating the self-adaptive reference and adopting an efficient adjustment means, the matching precision and appearance quality consistency of the rear-end component are improved, and meanwhile, the adjustment difficulty and the production cost are reduced.

Description

Technical Field

[0001] This application relates to the field of automotive manufacturing technology, and in particular to a method for adjusting the rear end of an automobile. Background Technology

[0002] Currently, the overall appearance quality of a vehicle is a key indicator for measuring manufacturing standards. The rear end of the vehicle involves the coordinated assembly of several large body panels, such as the tailgate, combination taillights, and rear bumper. The gaps and surface differences between these components directly affect the consumer's sensory experience and are crucial to achieving the desired vehicle dimensional engineering (DTS).

[0003] Regarding the aforementioned issues, traditional rear-end adjustment processes primarily rely on strict dimensional chain management. This mainly involves imposing high manufacturing tolerances on each individual sheet metal or plastic part, such as the tailgate, side panels, and rear bumper. On the assembly line, operators use adjustment tools or jigs specific to each part to adjust the tailgate position or perform localized matching during rear bumper installation. These adjustments are typically performed in isolation.

[0004] The above methods have limitations. They do not address the problem at the system level, and tolerances accumulate at each stage during assembly. Adjustments to subsequent components often disrupt the matching state already achieved in the preceding stages, leading to repetitive work. Over-reliance on individual component tolerances also directly increases the manufacturing cost of parts. Dimensional deviations are frequent on the assembly floor, resulting in high rework hours. Ultimately, the consistency of the vehicle's rear-end appearance quality is difficult to guarantee consistently, and the overall matching effect is extremely sensitive to even minor fluctuations in upstream components.

[0005] Therefore, the present invention provides a method for adjusting the rear end of an automobile to address the shortcomings of the prior art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for adjusting the rear end of an automobile, which aims to solve the problems of low dimensional matching accuracy and poor adjustment efficiency caused by the accumulation of tolerances in the rear end components during the existing automobile manufacturing process.

[0007] This invention provides the following solution: a method for adjusting the rear end of a vehicle, comprising the following sequential steps:

[0008] Step S1: The assembly of the tailgate of the body-in-white is carried out in the welding workshop, including: using a through-type assembly and adjustment tool to physically limit the gap between the tailgate and the roof and side panels of the body, and adjusting the Z-axis adjustable hinge structure to make a rough adjustment of the tailgate relative to the body reference position, laying the initial geometric foundation for subsequent final assembly adjustments.

[0009] Step S2: Implement an online punching process for the taillight positioning holes, including: using a laser scanner to scan the outer contour of the taillight matching area on the side of the vehicle body, establishing a local spatial coordinate system based on the outer contour, calculating the punching position according to the set size technical specifications, and having a robotic arm perform the punching, thereby providing a reference positioning hole for the side taillight.

[0010] Step S3: Install the rear door lock in the final assembly workshop, including: using special assembly tools or aligning the buckle position according to the body markings to provide a consistent locking reference for subsequent adjustments;

[0011] Step S4: Based on the consistent locking reference, close the tailgate, and use the internal clearance adjustment tool to check and adjust the tailgate, constrain the internal fit dimensions between the tailgate and the vehicle body flange edge, and finally determine the closed position of the tailgate;

[0012] Step S5: After the closing position of the tailgate is finally determined, the tailgate light and the side taillight are assembled, including: installing the side taillight in the reference positioning hole as a fixed geometric reference, and using the exposed adjustable mounting screws to make a secondary fine adjustment of the position of the tailgate light so that the tailgate light and the side taillight are aligned.

[0013] Step S6: After aligning the taillights with the side taillights, install and adjust the rear bumper, including: using an adjustable positioning mechanism on the mounting structure of the matching area between the rear bumper and the taillight to make the rear bumper match the adjusted taillight and the side of the vehicle body.

[0014] By adopting the above technical solution, this method decomposes the complex dimensional chain of the vehicle's rear end into multiple independent adjustment loops by setting continuous and logically related adjustment steps at different stages such as welding and final assembly. For example, the absolute reference for the side taillights is first established through online punching, then the locking reference for the tailgate is established through latch positioning, and finally the rear bumper is adjusted based on the tailgate and side panels. This achieves systematic control from coarse to fine adjustment, and from the main body to accessories. Therefore, this method can effectively break the cumulative transmission of tolerances, ensuring that the gaps and surface differences between various components can stably meet the dimensional technical specifications, thereby improving the consistency of the overall vehicle appearance quality. At the same time, it reduces the reliance on high-precision manufacturing of individual parts and reduces rework time and manufacturing costs on the production line.

[0015] Preferably, the Z-axis adjustable hinge structure includes a hinge base plate fixed to the side of the vehicle body. The hinge base plate is provided with an elongated hole extending in the vertical direction of the vehicle body, and the Z-axis sliding adjustment of the hinge base plate relative to the vehicle body is realized through the elongated hole.

[0016] By adopting the above technical solution, utilizing the Z-axis sliding margin provided by the elongated hole, and in conjunction with the forced positioning of the through-type assembly and adjustment fixture, the vertical position adjustment of the tailgate no longer depends on the manufacturing precision of the parts themselves, but instead depends on the positioning precision of the tooling, effectively cutting off the Z-axis dimensional chain.

[0017] Preferably, the through-type assembly and adjustment tool includes: a rear door and top cover gap limiting module, a rear door and side panel gap limiting module, and a rear door simulated lock ring pad, which are used to constrain the Y-axis and Z-axis, X-axis and Z-axis references of the rear door, respectively.

[0018] By adopting the above technical solution, each module of the auxiliary tool is connected to the body reference, providing rigid and all-round geometric constraints for the initial position of the tailgate in the body-in-white stage, ensuring that subsequent final assembly adjustments have a high-precision starting reference.

[0019] Preferably, the step of establishing a local spatial coordinate system includes: identifying the geometric feature edges and main mating surfaces on the outer side panel of the vehicle body as appearance matching references, and fitting and establishing a local spatial coordinate system that changes with the actual posture of the vehicle body based on the actual measurement data of the appearance matching references.

[0020] By adopting the above technical solution, the coordinate system is established directly based on the actual appearance contour of the vehicle body side panel, rather than a fixed theoretical model. This coordinate system can adapt to the actual deformation state of each vehicle body, thus providing a real and adaptive positioning reference for subsequent punching calculations and solving the problem of mismatch between hole positions and appearance caused by vehicle body welding deformation.

[0021] Preferably, the step of calculating the punching position includes: mapping the standard theoretical coordinates of the taillight positioning hole to a real-time established local spatial coordinate system through a coordinate transformation matrix to generate the compensated target punching point.

[0022] By employing the aforementioned technical solution, this calculation process combines ideal design data with actual measurement data. Specifically, the system maps the standard theoretical coordinates of the positioning hole in the design model to a local spatial coordinate system established based on the actual vehicle body contour through a coordinate system transformation operation. This calculation process essentially uses the actual pose information of the vehicle body to correct the theoretical point position, thereby generating a target punching point position that automatically compensates for vehicle body manufacturing deviations. This ensures that the taillight installed at this hole position can be precisely aligned with the vehicle body's exterior contour, achieving zeroing of the positioning hole's size relative to the exterior contour.

[0023] Preferably, the inner clearance adjustment accessory includes a positioning base that matches the profile of the sheet metal flange at the tailgate opening, and a measuring module whose thickness is set according to the theoretical thickness of the sealing strip under compression. The verification step is completed by judging the physical contact state between the inner panel of the tailgate and the surface of the measuring module.

[0024] By adopting the above technical solution, the invisible sealing function requirements are transformed into visible and measurable geometric clearance verification. This method is intuitive and reliable, ensuring the consistency of the vehicle's overall sealing performance and door closing quality.

[0025] Preferably, the adjustable mounting structure of the tailgate light includes an exposed adjustment and fastening assembly. The heads of the adjusting screws or fastening bolts of this assembly are located on the side edge or bottom of the light fixture, or are directly accessible through process holes on the light fixture cover, allowing adjustment from outside the vehicle without removing the interior trim panel. Specifically, with the tailgate closed and locked, the position of the tailgate light is adjusted using the exterior surface or characteristic ridge line of the installed side taillights as an alignment reference until it is flush with the ridge line of the side taillights.

[0026] By adopting the above technical solution, the adjustment logic of using the side taillights as a fixed reference and the taillights as a following adjustment component was clarified. The exposed adjustment structure allows for fine-tuning in the final assembly state, achieving a final and precise match between the gaps and surface differences of the split combination lights. Moreover, the adjustment process does not require disassembling any interior parts, improving adjustment efficiency and accuracy.

[0027] Preferably, the adjustable positioning mechanism is an eccentric bolt, or a bolt set in an elongated hole, or a floating nut plate, used to achieve a slight displacement of the rear bumper relative to the vehicle frame before tightening.

[0028] By adopting the above technical solution, this structure endows the rear bumper, the final component in the dimensional chain, with the ability to make minor adjustments relative to the vehicle body. This flexible compensation mechanism effectively cuts off the tolerances accumulated and transmitted from upstream components such as the body-in-white and the tailgate, allowing the rear bumper to achieve optimal matching with surrounding components independently, thus ensuring the final appearance quality of the entire vehicle's rear end.

[0029] Preferably, the step of positioning and assembling the latch is achieved by a special assembly tool, which has positioning features that cooperate with the reference hole or positioning surface of the body-in-white, and is used to constrain the latch in a uniform position before fastening.

[0030] By adopting the above technical solution and utilizing specialized assembly fixtures, a high degree of consistency in the installation position of the tailgate latches on all vehicles was ensured. This provides a stable and deviation-free locking benchmark for subsequent fine adjustments such as tailgate internal gaps and surface differences, avoiding repeated adjustments caused by latch position fluctuations and improving overall assembly efficiency.

[0031] The above solution achieves the following beneficial technical effects:

[0032] This application utilizes laser scanning and in-line punching processes to provide high-precision reference positioning holes for the side taillights based on the actual contours of the vehicle body. This step does not rely on upstream theoretical dimensions but directly creates a precise physical reference on the final welded body. Subsequent adjustments to the tailgate, tailgate lights, and rear bumper are all based on or referenced to this, decomposing the complex full-sequence dimensional chain into multiple independent and controllable adjustment stages. This effectively cuts off the accumulation and transmission of tolerances, thereby improving the final matching accuracy of gaps and surface differences between rear-end components.

[0033] This application utilizes exposed adjustment and fastening components to adjust the rear door lights, allowing operators to make minor adjustments from the outside without disassembling the interior trim panels, thus shortening processing time. Simultaneously, specialized assembly tools and internal clearance adjustment tools standardize and simplify the positioning and verification process of key benchmarks, reducing repetitive adjustments caused by human error. The application of this series of efficient adjustment methods and tools increases the production cycle time of the final assembly line and reduces rework costs due to dimensional mismatches.

[0034] The continuous adjustment process constructed in this application establishes a set of interconnected benchmark transfer and tolerance compensation logic. Adaptive punching for each vehicle body and a compensatory adjustment mechanism for the rear bumper ensure that the final appearance matching effect no longer relies entirely on the high-precision manufacturing of upstream components. Instead, it uses a systematic adjustment method to digest and absorb inherent manufacturing deviations. Therefore, this method ensures that the rear appearance of different batches and different vehicles meets a uniform high standard, resulting in more stable and reliable product quality. Attached Figure Description

[0035] Figure 1 This is the overall flowchart of the automotive rear-end welding adjustment method of the present invention.

[0036] Figure 2 This is a flowchart of the welding and rough adjustment process for the rear door of the present invention.

[0037] Figure 3 This is a flowchart of the online punching process for the taillight positioning hole of the present invention.

[0038] Figure 4 This is a flowchart of the assembly process for the rear door lock of the present invention.

[0039] Figure 5 This is a flowchart of the rear door inner gap adjustment process of the present invention.

[0040] Figure 6 This is a flowchart of the assembly and adjustment process of the combined lighting fixtures of the present invention.

[0041] Figure 7 This is a flowchart of the rear bumper installation and adjustment process of the present invention.

[0042] Figure 8 This is a flowchart of the adjustment method for the Z-axis adjustable hinge of the present invention.

[0043] Figure 9 This is a schematic diagram of the Z-axis adjustable hinge of the present invention.

[0044] Figure 10 This is a schematic diagram of the structure of the rear door inner gap adjustment accessory of the present invention.

[0045] Figure 11 This is a schematic diagram of the adjustable mounting structure for the rear door light of the present invention.

[0046] Among them, 1. tailgate connecting mechanism; 2. high-strength connecting mechanism; 3. body fastening bolts; 4. taillight adjustment mechanism; 5. special adjustment hole for nuts. Detailed Implementation

[0047] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0048] See attached document Figure 1 This invention provides a method for adjusting the rear end of an automobile. This method achieves vehicle dimensional technical specifications (DTS) by introducing adjustable structures and precise processes during the welding, post-processing, and final assembly stages of vehicle body manufacturing. The method flow may include the following sequential steps:

[0049] Step S1: Assemble the tailgate of the body-in-white in the welding workshop. This step includes using a through-type assembly tool to physically limit the gap between the tailgate and the roof and side panels of the body. At the same time, by adjusting the Z-axis adjustable hinge structure, the reference position of the tailgate relative to the body is coarsely adjusted to eliminate assembly tolerances during the welding process and ensure the basic positional accuracy of the tailgate in the body-in-white stage.

[0050] Step S2: Before or after painting (post-processing stage), an online punching process is performed on the taillight positioning holes. This step does not rely on pre-punched holes, but uses a high-precision laser scanner to scan the outline of the taillight matching area on the side of the vehicle body, establishing a local spatial coordinate system based on the outline. According to the set DTS data, the optimal punching position is calculated, and a robotic arm precisely executes the punching, achieving zeroing of the relative dimensions between the taillight positioning holes and the vehicle body outline.

[0051] Step S3: Install the tailgate lock in the final assembly workshop. This step uses specialized assembly tools or body markings to position and assemble the latch. The assembly tools ensure high consistency in the latch position across all vehicles, providing a stable locking reference for subsequent tailgate fine-tuning.

[0052] Step S4: Use an internal clearance adjustment tool to control the internal clearance between the tailgate and the body fitting area. This tool is used to verify and constrain the internal fit dimensions between the tailgate and the body flange edge before installing interior trim panels and seals, ensuring the performance of vehicle functions (such as sealing and door closing sound).

[0053] Step S5: After the tailgate body is adjusted, assemble the tailgate light and side taillights. The tailgate light uses an adjustable plastic snap-fit ​​structure to connect to the tailgate. Furthermore, the tailgate light mounting screws are designed to be exposed and adjustable, allowing for secondary fine-tuning of the light fixture's position after the tailgate body clearance adjustment is completed, to achieve DTS (Distributed Lighting System) in the rear combination light area.

[0054] Step S6: Install and adjust the rear bumper. Adjustable positioning bolts or adjustable mounting threaded holes are provided on the mounting structure in the area where the rear bumper matches the tailgate. This adjustable structure allows for minor compensatory adjustments to the rear bumper relative to the vehicle body and tailgate, effectively breaking the dimensional chain between the rear bumper and tailgate, ultimately ensuring DTS (Distributed Traverse System) at the rear of the vehicle.

[0055] This method reduces the over-reliance on the tolerance of a single part by introducing adjustable or flexible structures and processes in multiple key stages, and realizes systematic control of the matching relationship of multiple parts and multiple directions at the rear end of the vehicle, thereby effectively reducing manufacturing costs and rework time.

[0056] The through-type assembly fixture used in this invention is a tooling system for positioning and limiting the tailgate during the welding of the body-in-white stage. The system is designed to be through-type, meaning that after the tailgate is installed in place, the key positioning components of the fixture can still pass through or contact the edge and internal features of the tailgate, providing rigid support and precise limiting to ensure that the tailgate is in the designed position the moment the hinges are fixed. This fixture system mainly consists of four functional modules used to constrain the tailgate in the X, Y, and Z directions, as well as its rotation around an axis:

[0057] The system includes a tailgate and roof gap limiting module, which is located at the connection area between the upper edge of the tailgate and the roof. Its function is to provide rigid limits in the Y-direction (lateral direction of the vehicle body) and Z-direction (vertical direction of the vehicle body), constraining the installation position of the top edge of the tailgate. This limiting module ensures that the gap and surface difference between the tailgate and roof meet DTS requirements, preventing tolerance accumulation during the welding stage from causing top surface quality issues.

[0058] The system also includes left and right tailgate and side panel gap limiting modules, typically consisting of two independent tooling sets. These two limiting modules are located in the mating area between the tailgate's side edges and the vehicle's side panel outer plate. They are primarily used for X-axis (longitudinal) limiting to prevent the tailgate from shifting forward or backward during assembly, and simultaneously constrain the mating gap between the tailgate and the side panels, ensuring uniform appearance gaps between the tailgate and the side panels. These two modules serve as side panel gap limiting module one and side panel gap limiting module two during welding adjustments.

[0059] In addition, the auxiliary system includes a tailgate simulation lock ring pad to simulate the tailgate's locked and closed state during welding. This pad is positioned in the tailgate's locking area, contacting the locking structure on the tailgate and providing a Z-axis support reference. Since the final latch is not yet installed during the body-in-white stage, the pad's function is to counteract the tailgate's gravity, eliminate sag deviation in the free state, and ensure a uniform Z-axis reference in the tailgate's locking area.

[0060] All of the aforementioned limiting modules and pads are structurally fixed to external tooling and connected to the body-in-white reference point via high-precision positioning pins or detection surfaces. After the tailgate is welded or fixed, the penetrating auxiliary fixture is removed, and the geometric precision achieved through its rigid limiting is solidified in the body-in-white structure, laying the foundation for subsequent final assembly adjustments.

[0061] See attached document Figure 9In this embodiment, the Z-axis adjustable hinge structure is configured as a key moving component connecting the rear crossbeam area of ​​the body-in-white roof to the upper end of the tailgate. Its structural design aims to eliminate the cumulative manufacturing tolerances of the tailgate in the vertical direction, ensuring the surface difference accuracy between the tailgate and the roof. The hinge structure, as a whole, is a high-strength connection mechanism 2, mainly including a hinge base plate fixed to the side of the vehicle body and a tailgate connection mechanism 1 for connecting the tailgate.

[0062] The hinge base plate has at least two mounting holes for fasteners. These holes are specially designed as elongated oval holes extending vertically along the vehicle body, rather than traditional circular holes. The major axis of the elongated oval holes is parallel to the Z-axis of the vehicle body, providing a preset Z-axis sliding allowance for the hinge base plate relative to the vehicle body mounting point. The vehicle body fastening bolt 3 passes through the elongated oval holes and is screwed into the nut plate of the vehicle body sheet metal. When the fastening bolt is in a pre-tightened state but has not reached the final tightening torque, the hinge base plate can float up and down vertically within the stroke range defined by the elongated oval holes.

[0063] See attached document Figure 2 and attached Figure 8 The adjustment method based on the above structure includes the following steps: During the body-in-white assembly stage, the tailgate is first mounted to the body via hinges, and the hinge fastening bolts are tightened to a pre-tightened state. At this time, the hinge base plate still retains the freedom to make minor adjustments in the Z direction. Subsequently, the penetrating assembly and adjustment tool described in the previous embodiment is used to force the tailgate to be pushed up or pressed down to the theoretical Z-direction position specified in the design through the tailgate and roof gap limiting module. During this process, since the hinge mounting hole is an elongated hole structure, the hinge base plate will follow the forced positioning action of the penetrating assembly and adjustment tool, generating a corresponding Z-direction displacement on the body mounting surface, thereby automatically compensating for the Z-direction dimensional deviation caused by body welding or part stamping. After the penetrating assembly and adjustment tool locks the tailgate in the absolutely correct Z-direction position, the operator or automated equipment applies the final tightening torque to the hinge fastening bolts, using the friction of the bolt heads to permanently lock the hinge base plate in the current position. This process changes the vertical position accuracy of the tailgate from depending on the manufacturing accuracy of the parts to depending on the tooling positioning accuracy, effectively cutting off the transmission of the Z-direction dimensional chain.

[0064] This embodiment of the online punching system is integrated into a specific workstation or independent rework and adjustment area on the body-in-white production line. It aims to implement a vision-guided adaptive processing technology to address hole position deviations caused by welding deformation of the body side panels. The system's hardware architecture primarily consists of three core components: a non-contact vision acquisition unit, a data processing and control unit, and an automated punching execution unit. These three components achieve high-speed data interaction and collaborative control via an industrial fieldbus or real-time Ethernet.

[0065] Non-contact vision acquisition units are typically configured as one or more high-precision 3D laser contour scanners or blue light area scan cameras, rigidly fixed to a workstation bracket or mounted on the end effector of a separate measuring robot. Their field of view is configured to precisely align with the taillight mounting recess area and surrounding key surface areas of the vehicle's side panel. This acquisition unit possesses high-frequency sampling capabilities, configured to project laser lines or structured gratings onto the target sheet metal surface and receive light signals diffusely reflected from the surface, thereby generating high-density point cloud data containing microscopic geometric information of the object's surface. The measurement resolution of this vision acquisition unit typically reaches the micrometer level, sufficient to capture minute springback deformations, twists, or surface fluctuations generated in the side panel after stamping and welding processes, providing accurate physical data support for subsequent baseline reconstruction.

[0066] The data processing and control unit, as the core of the system's computation, communicates with both the output of the vision acquisition unit and the input of the punching execution unit. This unit integrates complex machine vision processing algorithms and kinematic solution logic, configured to receive raw scan data from the vision acquisition unit in real time and perform denoising, stitching, and surface feature extraction operations. Specifically, this unit can automatically identify specific geometric feature edges, R-angle transition areas, or feature surface patches on the side panel as appearance matching benchmarks, and fit a mathematical model based on these actually measured feature data, thereby establishing a local spatial coordinate system that changes with the actual posture of the vehicle body. This unit is also responsible for mapping the standard theoretical coordinates of the taillight positioning holes stored in the database to this real-time established local coordinate system through a coordinate transformation matrix, calculating the compensated target punching point position and normal vector, and generating corrected robot motion trajectory instructions.

[0067] The automated punching unit mainly consists of a multi-degree-of-freedom industrial robot and a dedicated stamping actuator mounted on its end effector. The multi-degree-of-freedom industrial robot typically employs a six-axis articulated robotic arm, capable of flexibly adjusting its end effector posture (position and angle) in three-dimensional space. It can dynamically track the vehicle body position based on correction coordinate commands sent by the data processing and control unit. The dedicated stamping actuator is designed as a lightweight yet highly rigid mechatronic tool, typically employing a C-jaw structure to facilitate entry into the punching area across the edges of the body sheet metal or reinforcing ribs. This mechanism integrates a servo electric cylinder or hydraulic drive unit to drive the punch and die to close, completing the metal shearing action. Furthermore, the stamping actuator can also integrate a floating compensation module and a blank holder, providing normal clamping force at the moment the punch contacts the sheet metal to prevent localized deformation and ensure that the punched taillight positioning hole edges are smooth, burr-free, and have extremely high positional accuracy relative to the side panel outline.

[0068] In this embodiment, the spatial coordinate system establishment method is configured as the primary core step in the online punching process. Its purpose is to reconstruct the actual physical shape of the taillight area on the side of the vehicle body using digital means, thereby providing a dynamic reference for subsequent punching operations. Specifically, this method begins with a non-contact vision acquisition unit scanning the taillight mounting area on the side of the vehicle body. During the scanning process, a high-precision laser contour scanner projects a laser beam onto the vehicle surface, covering the key appearance contour area where the side panel mates with the taillight. This area typically includes the flange surface used to limit the taillight mounting depth, the side edge lines used to form appearance gaps, and surrounding feature surfaces. The vision sensor receives reflected light signals and acquires massive amounts of three-dimensional point cloud data. This data accurately records the true geometric state of the body sheet metal after welding and cooling, including any existing distortion, springback, or positional deviations.

[0069] After acquiring the raw point cloud data, the data processing unit executes a series of preprocessing algorithms, including outlier removal, noise filtering, and surface smoothing, to eliminate measurement noise caused by sheet metal reflections, oil stains, or welding spatter. Subsequently, the system enters the feature extraction and fitting stage. Based on a preset feature model, the algorithm automatically identifies the geometric reference elements required to define the coordinate system in the purified point cloud. Specifically, the system first identifies the main mating surface data of the side panel outer plate that mates with the taillight housing. Using the least squares method or other surface fitting algorithms, these points are fitted into a mathematically meaningful reference plane or freeform surface. The normal vector of this fitted surface is defined as a principal axis direction of the local coordinate system (usually the Y-axis of the vehicle body or the Z-axis determined based on the flange surface normal), thereby constraining the three spatial degrees of freedom.

[0070] Next, the system extracts the appearance seam edges or feature ridges of the side panel outer shell from the point cloud, i.e., the boundary lines that form the appearance gap between the taillights and the body after installation. By fitting a straight line or spline curve to this edge feature, the system determines the second axis of the local coordinate system (e.g., the X or Z direction of the body), thereby constraining the other two spatial degrees of freedom. Finally, the system determines the position of the origin of the local coordinate system by calculating the intersection of the feature ridges with specific cross-sections, or by using the centers of existing process holes and feature corner points on the side panel as origin references, thereby locking the last translational degree of freedom.

[0071] Through the above steps, the system constructs a local three-dimensional Cartesian coordinate system attached to the actual body sheet metal surface within the algorithm. This local coordinate system is not fixed but dynamically floats according to the specific welding deformation of each body-in-white. The system ultimately generates a pose transformation matrix describing this local coordinate system relative to the robot base's global coordinate system. This matrix accurately quantifies the actual position and orientation of the current taillight area on the side of the body in space, ensuring that the subsequently calculated punching commands are strictly based on the current actual shape of the body, rather than the ideal theoretical position of the CAD model, thus achieving a geometric correlation between the positioning reference and the exterior contour.

[0072] The core operation of punching position calculation and execution in this embodiment is based on a following local spatial coordinate system. Within the data processing and control unit, this step begins by transforming the theoretical nominal coordinates of the taillight positioning holes stored in the database. The theoretical nominal coordinates represent the geometric relationship between the positioning hole and the taillight matching area's outline under an ideal CAD model. The data processing unit accurately maps these theoretical coordinate points to the actual three-dimensional space of the current body-in-white side panel using the local coordinate system pose transformation matrix generated in the previous step (this matrix includes the actual translation and rotation deviations of the vehicle body). The resulting coordinates are the corrected target punching point.

[0073] The corrected target punching point automatically compensates for deformation and positional deviations in the body-in-white side panel caused by manufacturing processes such as stamping and welding. The core feature of this point is that if a punch is made at this point, the installed taillight will be aligned with the appearance reference of the outer side panel in terms of its outline, thus achieving the technical effect of zeroing the relative size between the outline and the positioning hole.

[0074] Subsequently, the data processing and control unit sends the calculated and corrected target punching point (including position information and the normal vector information required for the punching direction) as a motion trajectory command to the multi-degree-of-freedom industrial robot of the automated punching execution unit. After receiving the command, the industrial robot's motion controller drives the robotic arm and the dedicated punching actuator mounted at the end effector to move precisely to the target punching point.

[0075] Before performing the punching operation, the stamping actuator first activates its built-in clamping device. This device provides a clamping force perpendicular to the sheet metal surface, fixing a localized area of ​​the side panel to the stamping die, preventing elastic deformation or movement of the thin sheet during stamping and shearing, thus ensuring the quality of the punched edges. Once the position and orientation are correct, the data processing and control unit triggers a servo electric cylinder or hydraulic drive within the stamping mechanism. Under the driving force, the punch penetrates the sheet metal to form a positioning hole. Because the punching execution point is calculated based on the actual exterior contour, the hole position achieves a precise geometric correlation with the vehicle body's exterior contour, eliminating the tolerance dependence of the hole position on the exterior contour in traditional pre-punching processes, and ensuring a perfect match between the taillights and the vehicle body during the final assembly stage.

[0076] See attached document Figure 4 This embodiment describes a tailgate latch consistency assembly strategy applied in the final assembly workshop. Its purpose is to reduce random positional deviations in the tailgate latch assembly caused by manual operation or tolerances on the vehicle body mounting surface, thereby ensuring that all body-in-whites have a uniform closing force and return reference when locked. This strategy achieves precise latch positioning by introducing standardized auxiliary assembly methods.

[0077] Standardized auxiliary assembly methods include one of two implementation paths:

[0078] The first implementation approach involves using a specialized assembly fixture. This fixture is designed as a high-rigidity positioning tool with precision-machined locating pins and / or locating surfaces that precisely mate with specific reference holes or locating surfaces on the vehicle body. Before the latch is installed, the operator positions the specialized fixture in the body latch ring area. This fixture has mounting cavities or limiting blocks for clamping or constraining the latch body. After the latch body is placed in the mounting cavity, the latch's position and orientation relative to the body reference are completely locked by the fixture. Subsequently, the fastening bolts are tightened to secure the latch to the body. After the bolts are tightened, the fixture is removed, and the latch's position is fixed in a highly consistent position precisely correlated with the body reference, achieving standardization of the latch position.

[0079] The second implementation approach utilizes pre-set high-precision markings on the vehicle body for positioning and installation. On the body-in-white or painted vehicle body, clear and precise crosshairs or straight lines are pre-made in the latch installation area using high-precision measurement or laser marking. These lines represent the theoretical center position and installation direction of the latch installation surface. When installing the latch, operators or automated equipment visually or through a vision system aligns reference features on the latch body (such as the center or edge of the bolt hole) with the markings on the body sheet metal. By ensuring precise alignment, the latch is fixed in the predetermined theoretical position.

[0080] Regardless of the approach taken, this assembly strategy ensures extremely low dispersion and high consistency in the geometric position of the tailgate latch. This consistency provides a stable locking benchmark for fine-tuning the tailgate during subsequent final assembly, effectively avoiding repeated adjustment processes caused by latch position fluctuations, and ensuring the stable achievement of performance indicators such as door gap, surface difference, and closing force when the tailgate is closed.

[0081] See attached document Figure 10 In this embodiment, the tailgate inner gap adjustment tool is configured as a special measuring tool for quantitatively detecting and controlling the normal distance between the tailgate inner panel and the body flange edge during the final assembly process.

[0082] This internal clearance is a key geometric parameter that determines the compression of the rear door seal, its rainwater leakage prevention performance, and the sound quality of the door closing. This accessory is designed to provide a rigid physical reference standard during the manufacturing window before the seal and interior panels are installed, to verify whether the tailgate's closing position meets the design compression requirements of the sealing system.

[0083] This adjustment tool is mainly composed of a positioning base, a measuring module, and a handheld unit, which are integrally molded or assembled. The bottom surface of the positioning base is machined into a negative shape that precisely matches the cross-sectional profile of the sheet metal flange edge at the tailgate opening of the vehicle body. This negative shape structure typically includes a groove or latch that can securely straddle or engage with specific detection points on the vehicle body flange edge, ensuring that the tool's position relative to the vehicle body reference surface is unique and stable during the detection process. The tool is made of engineering plastics (such as polyoxymethylene POM or nylon) with a certain degree of hardness and a smooth surface to prevent scratching the electrophoretic paint surface of the vehicle body during contact.

[0084] The measuring module is located on the top or side of the positioning base, and its thickness or height is precisely set based on the theoretical thickness of the tailgate sealing strip under design compression. Specifically, the upper surface of the measuring module represents the spatial plane that the tailgate inner panel should be in under ideal closed conditions. The measuring module may be equipped with go / no-go gauges or pressure sensors to determine whether the gap is within acceptable limits.

[0085] See attached document Figure 5 The adjustment process using the auxiliary tool is as follows: Before installing the tailgate sealing strip, the operator clips one or more inner clearance adjustment tools onto the key inspection areas of the tailgate frame (usually the left and right sides and the lower part, areas prone to sealing failure). Then, the operator closes the tailgate to the fully locked position. At this point, the corresponding area of ​​the tailgate inner panel will make physical contact with the measuring module surface of the tool.

[0086] The operator judges the contact state between the auxiliary tool and the inner panel of the tailgate based on the following: if the inner panel of the tailgate fits tightly against the surface of the measuring module without excessive interference, it indicates that the inner clearance at that point meets the design tolerance (DTS), and the sealing strip will achieve the ideal compression ratio after installation; if there are visible gaps or the door cannot be closed and locked, it indicates that the inner clearance is too large or too small. Based on this physical feedback, the operator fine-tunes the fore-and-aft position (X direction) of the tailgate striker or adjusts the limit buffer block until the contact state between the inner panel of the tailgate and the auxiliary tool reaches the preset standard. After confirming that it is qualified, the tailgate is opened, the adjustment auxiliary tool is removed, and the subsequent sealing strip and interior panel installation procedures are carried out. This step transforms the invisible sealing function into a visible geometric entity for control, ensuring the consistency of sealing performance for each vehicle.

[0087] This embodiment's combined lighting assembly and adjustment strategy primarily targets the split rear combination lighting system spanning the vehicle's side panels and tailgate, aiming to address the uneven flushness and gap issues caused by the matching tolerances between the vehicle body and the tailgate. The system defines the side panel taillights as position reference components and the tailgate lights as position following adjustment components, achieving precise visual alignment between the two through a specific structural design.

[0088] The side taillights are directly mounted to the outer side panel of the vehicle body. Thanks to the aforementioned vision-guided in-line punching process, the mounting holes for the side taillights have extremely high positional accuracy relative to the outer contour of the side panel. Therefore, once the side taillights are installed, their surface precisely matches the curved contour of the side panel without the need for additional mechanical adjustments, thus forming a geometric master reference for the entire rear combination light area not only relative to the vehicle body but also relative to the subsequently installed taillights.

[0089] See attached document Figure 11 The tailgate light is configured to be mounted on the tailgate sheet metal using an adjustable mounting structure with floating degrees of freedom. This structure mainly consists of positioning guide posts on the light fixture housing, elastic snap-fit ​​units, and exposed adjustment and fastening components. The positioning guide posts mate with mounting holes on the tailgate sheet metal, but the fit tolerance is designed to allow for a preset radial clearance, permitting slight X-axis (front-to-back) and Z-axis (up-down) sliding of the light fixture within the mounting plane. The elastic snap-fit ​​units provide temporary pre-tightening force before fastening, preventing the light fixture from falling off while maintaining its movable state.

[0090] The core feature of achieving DTS (Dual System Transmission) is the exposed adjustment and fastening assembly of the taillight adjustment mechanism 4. Unlike traditional installation methods that require removing the tailgate trim panel to access the internal nuts, this embodiment designs the head of the adjusting screw or fastening bolt to be located at the side edge, bottom, or a position directly accessible through concealed process holes such as the nut-specific adjustment hole 5 shown in the figure on the lamp cover. This exposed design allows adjustment tools (such as screwdrivers or sockets) to be directly accessed from outside the vehicle. The adjustment and fastening assembly, in conjunction with the elongated hole or groove structure on the lamp housing, can drive the tailgate light to move relative to the tailgate sheet metal when the adjusting screw is rotated, or allow the operator to manually push the lamp to the target position and then lock it in place while the fastening screw is loosened.

[0091] See attached document Figure 6 The specific adjustment process is as follows: After adjusting the main latches and internal gaps of the tailgate, the operator closes and locks the tailgate. At this time, the side taillights and the tailgate light are on the same visual plane. Using the luminous surface or characteristic ridge line of the side taillights as an alignment reference, the operator uses exposed adjustment fastening components to perform secondary fine adjustments to the tailgate light in the Z-direction height and X-direction surface difference without disassembling any interior panels or seals. By observing the dividing line and transition surface between the two lights in real time, the operator adjusts the tailgate light to be flush with the ridge line of the side taillights and evens out the gap between them. Finally, after tightening the exposed adjustment screws, the misalignment of the lights caused by the assembly tolerances of the tailgate itself is eliminated, ensuring the precise achievement of the overall vehicle rear lighting system's DTS (Design for Transformation) appearance.

[0092] This embodiment of the rear bumper adjustment scheme aims to solve the problem of difficulty in controlling the fit clearance and overlap difference between the rear bumper (rear bumper), which is the end component of the rear-end dimensional chain of the vehicle, and the body side panel and tailgate. This scheme effectively cuts off the transmission of the dimensional chain by introducing an adjustable positioning mechanism into the connection and installation structure between the rear bumper and the body, achieving flexible compensatory adjustment of the rear bumper position.

[0093] An adjustable positioning mechanism is configured in the mating area between the upper edge of the rear bumper and the lower part of the outer side panel of the vehicle body, as well as the lower edge of the tailgate. The core feature of this mechanism is that its mounting interface is designed to have an operable floating range. Specifically, the mechanism can adopt one of the following two structural designs:

[0094] The first type of structure uses adjustable positioning fastening bolts. In this design, the fastening bolts at the mounting points connecting the rear bumper to the vehicle frame are designed as eccentric bolts, or the bolts are positioned within an elongated hole extending laterally (Y-axis) or longitudinally (X-axis) along the vehicle body. When the bolts are loose or pre-tightened, the operator can achieve minor displacement compensation adjustments to the rear bumper's local position by rotating the eccentric bolt head or pushing the bolt within the elongated hole.

[0095] The second structure employs adjustable mounting threaded holes. In this design, the rear bumper body or its connecting bracket has pre-drilled circular bolt holes, and the threaded connection unit on the vehicle frame that mates with these holes (e.g., a threaded snap-fit ​​or floating nut plate) is designed to float. The floating nut plate is mounted on a base with a limiting frame, which has a preset floating range relative to the fixed position of the vehicle frame. During installation, the operator pushes the rear bumper to the target position using external force, and the floating threaded hole moves accordingly with the rear bumper. Subsequently, the fastening bolt is screwed into the floating nut plate and tightened, thereby locking the rear bumper in the currently fine-tuned compensated position.

[0096] See attached document Figure 7 Using the aforementioned adjustable positioning mechanism, the specific adjustment process is as follows: After adjusting the tailgate and side taillights, the operator installs the rear bumper and pre-tightens its mounting bolts. Then, using the lower edge of the tailgate and the rear wheel arch edge of the side panel as geometric references, the operator visually or with measuring tools inspects the mating surface difference and overlap gap between the rear bumper and these two components. If the inspection results show that the tolerances are out of tolerance, the operator adjusts the aforementioned adjustable positioning bolts or adjustable mounting threaded holes to compensate for a slight displacement of the rear bumper relative to the vehicle body. The purpose of this adjustment is to eliminate the impact of accumulated tolerances of the body-in-white, tailgate, and rear bumper components on the final appearance matching. By precisely locking the compensated rear bumper position, the DTS technical specifications of all exterior parts in the rear area of ​​the vehicle are ultimately achieved, ensuring the final uniformity of the vehicle's exterior dimensions and a high-quality feel.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for adjusting the rear end of a vehicle, characterized in that, It includes the following consecutive steps: S1. Assembly of the rear tailgate of the body-in-white in the welding workshop: Using a penetrating assembly and adjustment tool, the gap between the rear tailgate and the roof and side panels of the body is physically limited, and the reference position of the rear tailgate relative to the body is coarsely adjusted by adjusting the Z-axis adjustable hinge structure, laying the initial geometric foundation for subsequent final assembly adjustments. S2. Implement online punching process for taillight positioning holes: Use a laser scanner to scan the outer contour of the taillight matching area on the side of the vehicle body, establish a local spatial coordinate system based on the outer contour, calculate the punching position according to the set size technical specifications, and have a robot perform punching to provide a reference positioning hole for the side taillight. S3. Install the rear door lock in the final assembly workshop: Use special assembly tools or the body markings to position and assemble the latch, providing a consistent locking reference for subsequent adjustments. S4. Based on the consistent locking reference, close the tailgate, and use the internal clearance adjustment tool to check and adjust the tailgate, constrain the internal fit dimensions between the tailgate and the vehicle body flange edge, and finally determine the closed position of the tailgate. S5. After the closing position of the tailgate is finally determined, the tailgate light and the side taillight are assembled: the side taillight is installed in the reference positioning hole as a fixed geometric reference, and the position of the tailgate light is finely adjusted a second time using the exposed adjustable mounting screws so that the tailgate light and the side taillight are aligned. S6. After aligning the taillights on the rear door with the side taillights, install and adjust the rear bumper: use an adjustable positioning mechanism on the mounting structure of the matching area between the rear bumper and the taillight to make the rear bumper match the adjusted taillight and the side of the vehicle.

2. The method for adjusting the rear end of a vehicle according to claim 1, characterized in that, In step S1, the Z-axis adjustable hinge structure includes a hinge base plate fixed to the side of the vehicle body. The hinge base plate is provided with an elongated hole extending in the vertical direction of the vehicle body, and the Z-axis sliding adjustment of the hinge base plate relative to the vehicle body is realized through the elongated hole.

3. The method for adjusting the rear end of a vehicle according to claim 1, characterized in that, In step S1, the penetrating installation and adjustment tool includes: a rear door and top cover gap limiting module, a rear door and side panel gap limiting module, and a rear door simulated lock ring pad, which are used to constrain the Y-axis and Z-axis, X-axis and Z-axis references of the rear door, respectively.

4. The method for adjusting the rear end of a vehicle according to claim 1, characterized in that, In step S2, the step of establishing a local spatial coordinate system includes: identifying the geometric feature edges and main mating surfaces on the outer side panel of the vehicle body as appearance matching references, and fitting and establishing a local spatial coordinate system that changes with the actual posture of the vehicle body based on the actual measurement data of the appearance matching references.

5. The method for adjusting the rear end of a vehicle according to claim 4, characterized in that, In step S2, the step of calculating the punching position includes: mapping the standard theoretical coordinates of the taillight positioning hole to the real-time established local spatial coordinate system through a coordinate transformation matrix to generate the compensated target punching point.

6. The method for adjusting the rear end of a vehicle according to claim 1, characterized in that, In step S4, the inner clearance adjustment accessory includes a positioning base that matches the profile of the sheet metal flange edge at the tailgate opening of the vehicle body, and a measuring module whose thickness is set according to the theoretical thickness of the sealing strip under compression. The verification step is accomplished by determining the physical contact state between the inner panel of the rear door and the surface of the measuring module.

7. The method for adjusting the rear end of a vehicle according to claim 1, characterized in that, In step S5, the adjustable mounting structure of the tailgate light includes an exposed adjustment fastening assembly. The head of the adjusting screw or fastening bolt of the exposed adjustment fastening assembly is located on the side edge or bottom of the light fixture, or can be directly accessed through the process hole on the light fixture cover, so as to enable adjustment from the outside of the vehicle without removing the interior panel.

8. A method for adjusting the rear end of a vehicle according to claim 7, characterized in that, In step S5, the secondary fine-tuning step includes: with the tailgate in the closed and locked state, using the appearance surface or feature edge of the installed side taillight as the alignment reference, adjusting the position of the tailgate light until the tailgate light is flush with the edge of the side taillight.

9. The method for adjusting the rear end of a vehicle according to claim 1, characterized in that, In step S6, the adjustable positioning mechanism is an eccentric bolt, or a bolt set in an elongated hole, or a floating nut plate, used to achieve a slight displacement of the rear bumper relative to the vehicle frame before tightening.

10. A method for adjusting the rear end of a vehicle according to claim 1, characterized in that, In step S3, the step of positioning and assembling the latch is achieved by a special assembly tool. The special assembly tool has positioning features that cooperate with the reference hole or positioning surface of the body-in-white, and is used to constrain the latch in a uniform position before fastening.

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