Digital group matching process applied to deflection control of stainless steel car body

Abstract

The application discloses a digital assembling process applied to stainless steel vehicle body deflection control, draws a target arc and a chord connecting two end points on the target arc in CATIA software; after the tool deflection support positions of key components in vehicle synthesis are determined, target positions corresponding to the tool deflection support positions of the key components are determined on the chord, the distance between the target positions and target points corresponding to the target positions on the target arc is taken as a theoretical deflection value corresponding to the tool deflection support positions of the corresponding key components; based on the theoretical deflection value corresponding to the tool deflection support positions of the key components, CATIA software is used to simulate and analogize the assembling process of the side wall, and the theoretical deflection value corresponding to the tool deflection support positions of the key components is adjusted based on the simulation and analogization results to obtain preset deflection standard values corresponding to the tool deflection support positions of the key components, so that the precise matching of the side wall and the chassis deflection can be realized in the vehicle synthesis stage.

Description

Technical Field

[0001] This invention relates to the field of stainless steel subway vehicle manufacturing technology, and in particular to a digital assembly process for controlling the deflection of stainless steel car bodies. Background Technology

[0002] The stainless steel bus body is mainly composed of core components such as the roof, side walls, end walls, and underframe, which are connected by spot welding or arc welding. Deflection, as a key technical indicator for measuring the structural stiffness of the bus body, directly determines its load-bearing capacity. Deflection is defined as the chord height corresponding to the chord length within the bus headrest. To meet the load-bearing requirements of internal equipment and passengers during the bus's service life, the stainless steel bus body, after manufacturing, must meet the design standard of an upward deflection of 8-14mm in the headrest area and a downward deflection of 0-5mm in the outer headrest area. Based on this, during the bus body manufacturing stage, the deflection of the underframe and side walls needs to be pre-fabricated to ensure that the final deflection of the entire vehicle meets the design requirements.

[0003] The vehicle body assembly process is carried out sequentially according to the assembly order of underframe → end wall → side wall → roof. The underframe deflection is prefabricated by adjusting the height of the support device, such as... Figure 1 As shown, ensure that the upper surface of the support device is in close contact with the base frame structure surface. The prefabrication of the side wall deflection uses a deflection block positioning process; the deflection blocks are typically placed at the lower part of the doorposts.

[0004] During the prefabrication of sidewall deflection, deviations in critical dimensions such as the center distance between adjacent doors and windows are prone to occur. During vehicle assembly, the actual deflection of the assembled sidewall must precisely match the prefabricated deflection of the underframe to ensure overall vehicle assembly quality. If the deflection matching between the sidewall and underframe is poor during the vehicle assembly stage, operators must perform secondary adjustments to the sidewall, underframe, and other components, requiring the application of external force using tools such as traction straps for correction. This operation not only generates significant residual stress within the vehicle body, leading to increased deformation after subsequent welding processes, but also easily causes bulge defects at the connection between the sidewall and underframe, resulting in excessive sidewall flatness and ultimately affecting the overall assembly dimensions and structural stability of the vehicle body, thus impacting production efficiency. Furthermore, the deflection parameter settings in the existing sidewall assembly process largely rely on the experience and judgment of process engineers, lacking quantitative digital guidance. This makes it easy for sidewall deflection to exceed tolerances during the initial vehicle trial production stage. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the existing technology and provide a digital assembly process for controlling the deflection of stainless steel vehicle bodies. This process is used to solve the problem that the assembled side walls and door panels do not meet the design standards and that the deflection of the side walls and the deflection of the chassis do not match during the overall vehicle assembly stage.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The digital assembly process disclosed in this invention for controlling the deflection of stainless steel vehicle bodies includes:

[0008] Obtain the known chord length BC and the preset deflection value ED;

[0009] Based on the chord length BC and the preset deflection value ED, draw the target arc and the chord connecting the two ends of the target arc in CATIA software.

[0010] Locate the tooling drawings to determine the deflection support positions of the tooling for each key component during vehicle assembly;

[0011] Determine the target position on the chord corresponding to the tooling deflection support position of each key component. The distance between the target position and the target point on the target arc corresponding to the target position is taken as the theoretical deflection value corresponding to the tooling deflection support position of the corresponding key component.

[0012] Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of each key component, the assembly process of the sidewall synthesis was simulated using CATIA software. Based on the simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of the key components were adjusted to obtain the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component.

[0013] Furthermore, the key components include segmented side walls and side wall doorways. Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of each key component, the assembly process of the side wall synthesis is simulated using CATIA software, including the following steps:

[0014] Complete the 3D modeling of the stainless steel vehicle body, consisting of segmented side walls and side doorways, in the CATIA software environment;

[0015] Determine the target positions corresponding to the tooling deflection support positions of the side wall doorway and the segmented side walls on the chord. Using the theoretical deflection value corresponding to the tooling deflection support position of the segmented side wall as the distance, and using the target position corresponding to the tooling deflection support position of the segmented side wall as the starting point, determine the arrangement position of the segmented side wall and arrange the segmented side wall at the arrangement position of the segmented side wall. Using the theoretical deflection value corresponding to the tooling deflection support position of the side wall doorway as the distance, and using the target position corresponding to the tooling deflection support position of the side wall doorway as the starting point, determine the arrangement position of the side wall doorway assembly and arrange the side wall doorway assembly at the arrangement position of the side wall doorway assembly. The segmented side walls and the side wall doorway assembly are arranged on the same side of the chord.

[0016] Based on the arrangement of side wall entrances and segmented side walls, the entire process of assembling the side walls is simulated using CATIA software.

[0017] Furthermore, based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components are adjusted to obtain preset standard deflection values ​​corresponding to the tooling deflection support positions of each key component, including...

[0018] The entire process of simulation fully considers the dimensional tolerances of the side wall doorway components and the segmented side walls. It detects each key dimension in the segmented side walls, and for the target positions corresponding to the key dimensions that exceed the tolerance, it fine-tunes the theoretical deflection values ​​of the tooling deflection support positions corresponding to the target positions. Based on the fine-tuned theoretical deflection values, it performs a full-process simulation of the assembly process of the side wall synthesis until each key dimension is within the tolerance. The fine-tuned theoretical deflection values ​​are then used as the preset deflection standard values ​​for the corresponding tooling deflection support positions.

[0019] Furthermore, the theoretical deflection value of the tooling deflection support position corresponding to the target position is fine-tuned, including reducing the theoretical deflection value of the tooling deflection support position corresponding to the target position of the key dimension by 1-2mm when the key dimension exceeds the upper limit of the tolerance.

[0020] Furthermore, based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components are adjusted to obtain the preset standard deflection values ​​corresponding to the tooling deflection support positions of each key component, including:

[0021] It is necessary to fully consider the dimensional tolerance fluctuations that may exist in the composition of the side wall doorway and the segmented side wall during the actual production process, and to reasonably integrate the tolerance range into the simulation model to simulate the dimensional deviation scenarios in the actual assembly.

[0022] Furthermore, key dimensions include the upper assembly gap of the segmented side wall, the center distance between adjacent doors, the center distance between windows, and the total length of the upper and lower parts of the side wall.

[0023] Furthermore, based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components are adjusted to obtain the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component, which also includes:

[0024] For interference locations where interference occurs on the upper part of the segmented sidewalls during the full-process simulation, a fine-tuning method is adopted to gradually adjust the theoretical deflection value of the tooling deflection support position corresponding to the interference location. After each fine-tuning, the simulation is re-verified, and the optimization is iterated repeatedly until all key dimensions are within the tolerance requirements and there is no interference from any components. Then, the fine-tuned theoretical deflection value is set as the preset standard deflection value of the corresponding tooling deflection support position.

[0025] Furthermore, based on the preset deflection standard values ​​of the tooling deflection support positions of each key component, a schematic diagram of the composite arrangement of the side walls is drawn.

[0026] Furthermore, based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components, and combined with the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component, the deflection values ​​at various positions of the chassis are finely adjusted during the vehicle assembly stage to ensure precise matching between the sidewalls and the chassis deflection.

[0027] Further, based on the chord length BC, deflection technical parameters, and preset deflection value ED, the target arc and the chord connecting the two endpoints of the target arc are drawn in CATIA software, including:

[0028] Based on the chord length BC and the preset deflection value ED, the radius R of the arc corresponding to the deflection is calculated using the following formula:

[0029] R 2 = (BC / 2) 2 +(R-ED) 2 ;

[0030] After obtaining the R value, draw a circle with radius R in CATIA software, and draw a chord with length BC on the circle. The arc on the circle corresponding to the chord is the target arc.

[0031] In the above technical solution, the digital assembly process for stainless steel vehicle body deflection control provided by the present invention is compared with the prior art.

[0032] This process, based on the acquired arc chords, determines the tooling deflection support position during vehicle assembly. The distance between the target point on the target arc and the target position is used as the theoretical deflection value corresponding to the tooling deflection support position of the corresponding key component. After determining the theoretical deflection value, the theoretical deflection value is adjusted through CATIA digital simulation and pre-playing to obtain the preset deflection standard value corresponding to the tooling deflection support position of each key component. This changes the traditional method of process personnel relying solely on experience to estimate the deflection value of each position, and can accurately control the assembly of each key component in the side wall structure to meet the design standards, avoiding the problems caused by the mismatch between the side wall deflection and the chassis deflection during the vehicle assembly stage. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0034] Figure 1 This is a schematic diagram of tooling layout during the assembly of a complete vehicle in the prior art;

[0035] Figure 2This is a schematic diagram of the digital assembly process preset deflection calculation for stainless steel vehicle body deflection control disclosed in this invention.

[0036] Figure 3 This is a partial schematic diagram of the tooling arrangement during the assembly of the sidewall of the digital assembly process for controlling the deflection of stainless steel vehicle bodies, as disclosed in this invention.

[0037] Figure 4 This is a schematic diagram of the digital assembly process deflection value simulation for stainless steel vehicle body deflection control disclosed in this invention.

[0038] Figure 5 This is a schematic diagram of the digital assembly process sidewall synthesis layout for stainless steel vehicle body deflection control disclosed in this invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0040] See Figure 2 As shown;

[0041] The invention relates to a digital assembly process for controlling the deflection of stainless steel vehicle bodies, specifically for the composite assembly of stainless steel vehicle body sidewalls, comprising the following steps:

[0042] Obtain the known chord length BC and the preset deflection value ED;

[0043] Based on the chord length BC and the preset deflection value ED, draw the target arc and the chord connecting the two ends of the target arc in CATIA software.

[0044] Specifically, based on the deflection requirements of the entire train sleeper (internal length of the sleeper beams on both sides) in the technical specifications for steel structure trains, the chord length BC and deflection parameters are obtained;

[0045] Taking into account factors such as welding deformation and deflection springback after the sidewall and vehicle body are combined, a preset deflection value ED is set for the front underframe of the sidewall and the whole vehicle.

[0046] The formula for calculating the radius R of the arc corresponding to the deflection is:

[0047] R 2 = (BC / 2) 2 +(R-ED) 2

[0048] Using BC and ED as the main parameters and R as the radius, the arc corresponding to the deflection is obtained, such as... Figure 2As shown, ED is the preset deflection value, BC is the length inside the pillow, and AB is the radius R. After obtaining the value of R, you can first draw a circle with radius R in CATIA software and then cut the chord length BC on the circle. Alternatively, you can first draw the chord length BC in the software and then obtain the circle with the two endpoints of the chord length and the radius, and finally obtain the arc corresponding to the deflection.

[0049] The entire process is based on formula calculation to determine the theoretical deflection value, which can effectively avoid problems such as unreasonable deflection settings caused by insufficient personnel experience in traditional processes, ensuring process stability and consistency, and forming a scientific combination scheme that can be promoted.

[0050] Locate the tooling drawings to determine the deflection support positions of the tooling for each key component during vehicle assembly;

[0051] Specifically, the composite deflection support blocks for the side walls are typically placed at the position of the doorposts, such as... Figure 3 As shown, to facilitate the calculation of deflection, since the position of the side wall door is fixed, the support position is also determined. The arrangement involves support blocks that conform to the shape of the lower part of the door pillar, fitting snugly against the pillar. More specifically, the support can be placed in the area next to the door pillar, within a range of approximately 100-200mm. During the assembly of the entire vehicle, the tooling arrangement involves the underframe deflection support blocks resting on the main crossbeam. The deflection blocks are placed according to the position of the main crossbeam (e.g., ...). Figure 1 (As shown).

[0052] Step 1: Determine the target position on the chord corresponding to the tooling deflection support position of each key component. The distance between the target position and the target point on the target arc corresponding to the target position is taken as the theoretical deflection value corresponding to the tooling deflection support position of the corresponding key component.

[0053] Specifically, the key components include the segmented side walls and the side wall doorway. The theoretical deflection value corresponding to the tooling deflection support position of each key component is determined by locating the tooling deflection support position of the side wall assembly and the whole vehicle assembly on the CATIA software, and measuring the distance between the chord length and the arc. This distance is the preset theoretical deflection value of the tooling deflection support position.

[0054] Step 2: Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of each key component, the assembly process of the sidewall synthesis is simulated in full using CATIA software. Based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of the key components are adjusted to obtain the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component.

[0055] Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of each key component, the assembly process of the sidewall synthesis was simulated using CATIA software, including the following steps:

[0056] Step 2.1: Complete the 3D model of the stainless steel vehicle body consisting of segmented side walls and side doorways in the CATIA software environment, ensuring that the model size and curvature are completely consistent with the design drawings;

[0057] Step 2.2: Determine the target positions on the chord corresponding to the tooling deflection support positions of the side wall doorway assembly and the segmented side walls, respectively. Using the theoretical deflection value corresponding to the tooling deflection support position of the segmented side wall as the distance, and using the target position corresponding to the tooling deflection support position of the segmented side wall as the starting point, determine the arrangement position of the segmented side wall and place it at the arrangement position of the segmented side wall. Using the theoretical deflection value corresponding to the tooling deflection support position of the side wall doorway assembly as the distance, and using the target position corresponding to the tooling deflection support position of the side wall doorway assembly as the starting point, determine the arrangement position of the side wall doorway assembly and place it at the arrangement position of the side wall doorway assembly. The segmented side walls and the side wall doorway assembly are arranged on the same side of the chord.

[0058] In other words, based on the theoretical deflection value obtained in step 1, the side wall door assembly and the segmented side wall are arranged on the arc line, so that the side wall door assembly and the segmented side wall are placed on the deflection positioning fixture, and the deflection support block is arranged at the door post position.

[0059] Step 2.3: Based on the arrangement of the side wall doorway and the segmented side walls, use CATIA software to perform a full-process simulation of the side wall synthesis assembly process;

[0060] Specifically, the simulation process fully considers the dimensional tolerances of the doorway components and the segmented side walls. It focuses on detecting key dimensions such as the assembly gap at the top of the segmented side walls, the center distance between adjacent doors and windows, and the top and bottom of the side walls. For positions that exceed the tolerances, the theoretical deflection value is fine-tuned. After the theoretical deflection value is calibrated, it prepares for the final determination of the preset deflection standard value of the side wall assembly.

[0061] Step 2.3.1: Based on the full-process simulation results, adjust the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components to obtain the preset standard deflection values ​​corresponding to the tooling deflection support positions of each key component, including:

[0062] The entire process of simulation fully considers the dimensional tolerances of the side wall doorway components and the segmented side walls. It detects each key dimension in the segmented side walls, and for the target positions corresponding to the key dimensions that exceed the tolerance, it fine-tunes the theoretical deflection values ​​of the tooling deflection support positions corresponding to the target positions. Based on the fine-tuned theoretical deflection values, it performs a full-process simulation of the assembly process of the side wall synthesis until each key dimension is within the tolerance. The fine-tuned theoretical deflection values ​​are then used as the preset deflection standard values ​​for the corresponding tooling deflection support positions.

[0063] Specifically, to address out-of-tolerance positions, fine-tuning measures are taken to adjust the theoretical deflection value of the tooling deflection support position corresponding to the target position. This includes reducing the theoretical deflection value of the tooling deflection support position corresponding to the target position of the critical dimension by 1-2 mm when the critical dimension exceeds the upper limit of the tolerance.

[0064] More specifically, if the center distance between adjacent doors exceeds the upper limit of the tolerance, the theoretical deflection value inside the door center may be reduced by 1-2mm, so that the value of the door center distance will decrease until it is adjusted to within the tolerance range; for positions where the gap between the doorway and the upper part of the side wall is large, the deflection value here will be reduced by 1-2mm, so that the gap between the two will be reduced until it is adjusted to within 2mm.

[0065] Based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components are adjusted to obtain the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component, which also includes:

[0066] For interference locations where interference occurs on the upper part of the segmented sidewalls during the full-process simulation, a fine-tuning method is adopted to gradually adjust the theoretical deflection value of the tooling deflection support position corresponding to the interference location. After each fine-tuning, the simulation is re-verified, and the optimization is iterated repeatedly until all key dimensions are within tolerance and there is no interference from any components. Then, the fine-tuned theoretical deflection value is set as the preset standard deflection value of the corresponding tooling deflection support position.

[0067] In the specific simulation process, the focus was on the dimensional inspection of key components, including the assembly gap at the top of the segmented sidewalls (which needed to be controlled within tolerance to avoid excessively large or small gaps affecting subsequent sidewall assembly welding), the center distance between adjacent doors, the center distance between windows, and the total length of the top and bottom of the sidewalls. This minimized deflection deviations caused by welding deformation. Through CATIA software simulation optimization, the segmented sidewalls and doorway components could be positioned strictly according to preset standard deflection values, thereby reducing operator intervention in forced assembly and significantly reducing residual stress generated during the assembly process. After subsequent spot welding, welding deformation was effectively controlled, thus ensuring the accuracy and stability of the vehicle body's key dimensions.

[0068] Based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components are adjusted to obtain the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component, and also include

[0069] To enhance the realism and guidance of simulation results, it is necessary to fully consider the dimensional tolerance fluctuations that may occur in the doorway components and segmented side walls during actual production. The tolerance range should be reasonably integrated into the simulation model to simulate dimensional deviation scenarios during actual assembly. For locations exceeding tolerances or where interference occurs at the top of the segmented side walls, the deflection parameters should be gradually corrected using a fine-tuning approach. After each fine-tuning, simulation verification should be performed again, iterating and optimizing repeatedly until all key dimensions strictly meet design tolerance requirements and there is no interference between components.

[0070] Step 2.4: Draw a schematic diagram of the composite arrangement of the side walls based on the preset deflection standard values ​​of the tooling deflection support positions of each key component.

[0071] Specifically, after all dimensions have been calibrated and the simulation results meet the design standards, the preset deflection standard value during the sidewall synthesis process is finally determined (i.e., the theoretical deflection value of each deflection support position in the actual synthesis is simulated, and the tooling is adjusted according to this deflection value), and the following is drawn: Figure 5 The diagram shows a simulated layout of the sidewalls.

[0072] 2.5 Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components, and combined with the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component, the deflection values ​​at various positions of the chassis are finely adjusted during the vehicle assembly stage to ensure precise matching between the sidewalls and the chassis deflection.

[0073] In other words, based on the theoretical deflection value of the whole vehicle assembly obtained in step 1, and combined with the preset standard deflection value after the sidewall assembly simulation in step 2, fine-tuning the deflection values ​​at various positions of the underframe during the whole vehicle assembly stage can achieve precise matching of the deflection between the sidewall and the underframe. This changes the traditional method of process engineers relying solely on experience to estimate the deflection values ​​at each position. It provides scientific and precise technical guidance for the sidewall and whole vehicle assembly operations in actual production, ensuring the assembly quality and production efficiency of sidewall and whole vehicle assembly.

[0074] This process uses preset theoretical deflection to precisely verify the tooling. The digitalization team verified the process through actual production, achieving precise matching of the sidewall and underframe deflection during the vehicle assembly stage, without any assembly defects such as sidewall bulges. This fully validates the effectiveness and feasibility of the process. Secondly, based on digital technology, a full-process simulation model of stainless steel body sidewall assembly and body assembly was constructed to accurately reproduce the process execution, enabling advance assessment of key dimensions and ensuring the deflection dimensions and process stability of the stainless steel body sidewall and body assembly. Furthermore, through digital... The assembly process utilizes the 3D modeling software CATIA for simulation calculations, enabling the construction of ultra-large radius circular arc models for simulation. Simultaneously, it avoids the reliance on manual assembly in traditional sidewall and body assembly processes, which require external force assistance using tools such as struts and straps for positioning. This process is cumbersome and lacks precision. The digital assembly process requires no additional external force throughout, significantly reducing operator workload. Furthermore, because precise deflection matching is achieved through simulation in the early stages of the process, secondary adjustments due to deflection mismatches are avoided, further significantly improving production efficiency.

[0075] A specific example is a subway project:

[0076] Based on the technical conditions of the steel structure train in the above project, the length of the entire car's sleeper is obtained. According to the deflection requirement of the chord length BC being 15850mm, the deflection parameter of the sleeper after the car body is assembled is required to be 8-14mm.

[0077] The preset deflection value ED, taking into account factors such as welding deformation and deflection springback after the side wall and vehicle body are combined, is set to 16mm for the pre-deflection value ED of the front underframe deflection of the side wall and the whole vehicle.

[0078] Using ED and BC as the main parameters, calculate the radius R of the arc corresponding to the deflection;

[0079] Use the formula:

[0080] R 2 = (BC / 2) 2 +(R-ED) 2

[0081] The radius R is 1962683.78 mm. Using CATIA software, a circle with R of 1962683.78 mm is drawn. The length of the chord BC intercepted on the circle is 15850 mm. The arc corresponding to the chord BC is the arc corresponding to the deflection.

[0082] Find the tooling drawings and clarify the deflection support positions of the segmented side walls and side wall doorways when assembling the whole vehicle. The deflection support blocks of the side wall assembly are placed 200mm away from the door pillar. The deflection support blocks of the underframe are supported on the main crossbeam. Place the deflection blocks according to the position of the main crossbeam.

[0083] Step 1: Determine the target position on the chord corresponding to the deflection support position of the tooling formed by the segmented side walls and the doorway of the side walls, such as... Figure 4 As shown, the deflection support position of the side wall assembly and the whole vehicle assembly tooling is located on the CATIA software, and the distance ED between the chord length BC and the arc is measured. This distance is the preset theoretical deflection value of the tooling deflection support position.

[0084] Step 2: Based on the theoretical deflection values ​​corresponding to the deflection support positions of the tooling composed of the segmented side walls and side wall doorways, the assembly process of the side wall synthesis is simulated in full using CATIA software. Based on the full-process simulation results, the theoretical deflection values ​​corresponding to the deflection support positions of the tooling composed of the segmented side walls and side wall doorways are adjusted to obtain the preset deflection standard values ​​corresponding to the deflection support positions of the tooling composed of the segmented side walls and side wall doorways.

[0085] Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of each key component, the assembly process of the sidewall synthesis was simulated using CATIA software, including the following steps:

[0086] Step 2.1: First, complete the 3D modeling of the segmented side walls in the CATIA software environment, ensuring that the model size and curvature are completely consistent with the design drawings;

[0087] Step 2.2: Based on the theoretical deflection value obtained in Step 1, arrange the side wall door assembly and the segmented side wall on the arc line, so that the side wall door assembly and the segmented side wall are arranged on the deflection positioning fixture. The deflection support block is usually arranged at the door post position.

[0088] Step 2.3: Based on the arrangement of the side wall door components and the segmented side walls, the CATIA software is used to simulate the entire process of side wall assembly. During the simulation, the dimensional tolerance factors of the door components and segmented side walls are fully considered. The key dimensions such as the assembly gap of the upper part of the segmented side walls, the center distance between adjacent doors and windows, and the total length of the upper and lower parts of the side walls are checked. For the positions that exceed the tolerance, the theoretical deflection value is finely adjusted. After the parameter calibration is completed, it is prepared for the final determination of the preset deflection standard value of the side wall assembly.

[0089] Step 2.3.1: Fine-tuning measures for out-of-tolerance positions. If the deflection value exceeds the upper limit of the tolerance, the deflection value should be reduced by 1-2 mm. For example, the upper length of the side wall (tolerance is +10, +20) should be assembled according to +20 during the assembly process. If the dimension exceeds +20, the maximum deflection position needs to be reduced by 1-2 mm to meet the assembly requirements of the side wall length.

[0090] For critical dimension inspection, the assembly gap at the top of the segmented sidewalls must be controlled within the tolerance range. Key dimensions such as the center distance between adjacent doors and windows must be checked to minimize deflection deviations caused by welding deformation. Simultaneously, the dimensional tolerance fluctuations that may occur in the doorway components and segmented sidewalls during actual production must be fully considered. The tolerance range must be reasonably integrated into the simulation model to simulate dimensional deviation scenarios during actual assembly. For locations exceeding tolerances or where interference occurs at the top of the segmented sidewalls, the deflection parameters are gradually corrected using a fine-tuning method. After each fine-tuning, simulation verification is performed again, iterating and optimizing repeatedly until all critical dimensions strictly meet the design tolerance requirements and there is no interference from any components. The theoretical deflection value after fine-tuning is then used as the preset standard deflection value for the corresponding tooling deflection support position.

[0091] Step 2.4: After all dimensions have been calibrated and the simulation results meet the design standards, the final standard value of the pre-set deflection at the top of the arc during the sidewall synthesis process is determined to be 15mm. The theoretical deflection value at each deflection support position in the actual synthesis is simulated. The fixture is adjusted according to this deflection value, and the following diagram is drawn: Figure 5 The diagram shows a simulated layout of the sidewalls.

[0092] Step 2.5: Based on the theoretical deflection values ​​obtained in Step 1 and the preset deflection standard values ​​from the sidewall assembly simulation in Step 2, fine-tune the deflection values ​​at various locations of the underframe by 1-2mm during the vehicle assembly stage. This achieves precise matching of the sidewall and underframe deflections, changing the traditional method of process engineers relying solely on experience to estimate deflection values ​​at each location. This provides scientific and precise technical guidance for sidewall assembly operations in actual production, ensuring the assembly quality and production efficiency of sidewall and vehicle body assembly.

[0093] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A digital assembly process applied to the deflection control of stainless steel vehicle bodies, characterized in that, include: Obtain the known chord length BC and the preset deflection value ED; Based on the chord length BC and the preset deflection value ED, draw the target arc and the chord connecting the two ends of the target arc in CATIA software. Locate the tooling drawings to determine the deflection support positions of the tooling for each key component during vehicle assembly; Determine the target position on the chord corresponding to the tooling deflection support position of each key component. The distance between the target position and the target point on the target arc corresponding to the target position is taken as the theoretical deflection value corresponding to the tooling deflection support position of the corresponding key component. Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of each key component, the assembly process of the sidewall synthesis was simulated using CATIA software. Based on the simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of the key components were adjusted to obtain the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component.

2. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 1, characterized in that, Key components include segmented side walls and side wall doorways. Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of each key component, the assembly process of the side wall synthesis is simulated using CATIA software, including the following steps: Complete the 3D modeling of the stainless steel vehicle body, consisting of segmented side walls and side doorways, in the CATIA software environment; Determine the target positions corresponding to the tooling deflection support positions of the side wall doorway and the segmented side walls on the chord. Using the theoretical deflection value corresponding to the tooling deflection support position of the segmented side wall as the distance, and using the target position corresponding to the tooling deflection support position of the segmented side wall as the starting point, determine the arrangement position of the segmented side wall and arrange the segmented side wall at the arrangement position of the segmented side wall. Using the theoretical deflection value corresponding to the tooling deflection support position of the side wall doorway as the distance, and using the target position corresponding to the tooling deflection support position of the side wall doorway as the starting point, determine the arrangement position of the side wall doorway assembly and arrange the side wall doorway assembly at the arrangement position of the side wall doorway assembly. The segmented side walls and the side wall doorway assembly are arranged on the same side of the chord. Based on the arrangement of side wall entrances and segmented side walls, the entire process of assembling the side walls is simulated using CATIA software.

3. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 2, characterized in that, Based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components are adjusted to obtain the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component, including... The entire process of simulation fully considers the dimensional tolerances of the side wall doorway components and the segmented side walls. It detects each key dimension in the segmented side walls, and for the target positions corresponding to the key dimensions that exceed the tolerance, it fine-tunes the theoretical deflection values ​​of the tooling deflection support positions corresponding to the target positions. Based on the fine-tuned theoretical deflection values, it performs a full-process simulation of the assembly process of the side wall synthesis until each key dimension is within the tolerance. The fine-tuned theoretical deflection values ​​are then used as the preset deflection standard values ​​for the corresponding tooling deflection support positions.

4. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 3, characterized in that: Fine-tune the theoretical deflection value of the tooling deflection support position corresponding to the target position, including reducing the theoretical deflection value of the tooling deflection support position corresponding to the target position of the critical dimension by 1-2mm when the critical dimension exceeds the upper limit of the tolerance.

5. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 3 or 4, characterized in that: Based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components are adjusted to obtain the preset standard deflection values ​​corresponding to the tooling deflection support positions of each key component, including: It is necessary to fully consider the dimensional tolerance fluctuations that may exist in the composition of the side wall doorway and the segmented side wall itself during the actual production process, and to reasonably integrate the tolerance range into the simulation model to simulate the dimensional deviation scenarios in actual assembly.

6. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 3 or 4, characterized in that: Key dimensions include the assembly gap at the top of the segmented side wall, the center distance between adjacent doors, the center distance between windows, and the total length of the top and bottom of the side wall.

7. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 6, characterized in that: Based on the full-process simulation results, the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components are adjusted to obtain the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component, which also includes: For interference locations where interference occurs on the upper part of the segmented sidewalls during the full-process simulation, a fine-tuning method is adopted to gradually adjust the theoretical deflection value of the tooling deflection support position corresponding to the interference location. After each fine-tuning, the simulation is re-verified, and the optimization is iterated repeatedly until all key dimensions are within tolerance and there is no interference from any components. Then, the fine-tuned theoretical deflection value is set as the preset standard deflection value of the corresponding tooling deflection support position.

8. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 3, characterized in that, Also includes: Based on the preset deflection standard values ​​of the tooling deflection support positions of each key component, a schematic diagram of the composite arrangement of the side walls is drawn.

9. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 1, characterized in that, Also includes: Based on the theoretical deflection values ​​corresponding to the tooling deflection support positions of key components, and combined with the preset deflection standard values ​​corresponding to the tooling deflection support positions of each key component, the deflection values ​​at various positions of the chassis are finely adjusted during the vehicle assembly stage to ensure precise matching between the sidewalls and the chassis deflection.

10. The digital assembly process for controlling the deflection of stainless steel vehicle bodies according to claim 1, characterized in that, Based on the chord length BC, deflection technical parameters, and preset deflection value ED, draw the target arc and the chord connecting the two endpoints of the target arc in CATIA software, including: Based on the chord length BC and the preset deflection value ED, the radius R of the arc corresponding to the deflection is calculated using the following formula: R 2 =(BC / 2) 2 +(R-ED) 2 ; After obtaining the R value, draw a circle with radius R in CATIA software, and draw a chord with length BC on the circle. The arc on the circle corresponding to the chord is the target arc.

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