A zero-switch compatible automobile rear wall assembly, automobile body and vehicle

Abstract

The application discloses a zero-switching compatible automobile rear wall assembly, a vehicle body and a vehicle, and relates to the technical field of automobile body structures. The zero-switching compatible automobile rear wall assembly comprises a rear wall outer plate and a rear wall inner plate, the rear wall outer plate and the rear wall inner plate form a double-plate closed cavity main bearing structure, welding points are uniformly distributed in a chessboard pattern along corresponding lap joint surfaces of the rear wall outer plate flange inner side and the rear wall inner plate, the edges of the rear wall outer plate and the rear wall inner plate are completely covered and closed, the rear wall inner plate is provided with a horizontal reinforcing rib and a vertical partition plate, and the rear wall outer plate and the rear wall inner plate jointly enclose a multi-cavity closed structure, the multi-cavity closed structure comprises an upper acoustic cavity, a middle load transmission cavity and a lower buffer energy absorption cavity. The rear wall outer plate and the rear wall inner plate are respectively provided with reserved welding point areas. The functional subassemblies of the rear wall assembly are integrated on the double-plate closed cavity structure, the whole can be preassembled as an independent assembly, and a modular general part is formed. The technical problem that the existing rear wall assembly cannot be compatible with two rear floor assembly configurations with a spare tire pool and without a spare tire pool is solved.

Description

Technical Field

[0001] This invention relates to the field of automotive body structure technology, and in particular to a zero-switching compatible automotive rear assembly, body, and vehicle. Background Technology

[0002] The rear panel assembly is the main load-bearing structure at the rear of the vehicle, undertaking multiple functions such as collision energy transfer, rear bumper installation, and fixation of rear functional components. Existing rear panel assemblies are typically welded together from an outer rear panel and an inner rear panel. The weld points between the two panels lack systematic planning, resulting in uneven distribution in the overlapping areas and significant localized stress concentrations. This makes it difficult to guarantee overall load-bearing reliability and fails to meet the connection strength requirements of rear floor assemblies with and without spare tire wells.

[0003] In addition, the existing rear panel assembly has a scattered arrangement of functional sub-components, lacking modular integrated design. It cannot be pre-assembled as an independent assembly and must be installed piece by piece on the vehicle welding line, resulting in complex assembly processes and low production efficiency. At the same time, the existing rear panel assembly does not form modular components with complete structure and standard interfaces, and cannot be adapted to both rear floor assemblies with and without spare tire pools. Different configuration models require different rear panel assemblies, resulting in a low level of product platformization. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a zero-switching compatible automotive rear panel assembly, body, and vehicle, which solves the problem that existing automotive rear panel assemblies cannot simultaneously adapt to both rear floor assemblies with and without spare tire pools.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention also provides a zero-switching compatible automotive rear panel assembly, including an outer rear panel and an inner rear panel. The outer rear panel and the inner rear panel are connected by multi-point resistance spot welding to form a double-plate closed cavity main load-bearing structure. The weld points are evenly distributed in a checkerboard pattern along the inner side of the flange of the outer rear panel and the corresponding overlapping surface of the inner rear panel. The edges of the outer rear panel and the inner rear panel completely cover and close each other. The inner rear panel is provided with transverse reinforcing ribs and longitudinal partitions, which together with the outer rear panel form a multi-chamber closed structure. The multi-chamber closed structure consists of an upper acoustic cavity, a middle load transfer cavity, and a lower buffer energy absorption cavity.

[0006] As a further implementation, it also includes an upper rear bumper bracket and a lower rear bumper bracket. The upper rear bumper bracket is fixed to the upper outer side of the outer rear panel by spot welding, and the lower rear bumper bracket is fixed to the lower outer side of the inner rear panel by spot welding. The upper and lower rear bumper brackets are also provided with bracket mounting holes. The weld points on the upper and lower rear bumper brackets are all arranged in the outer area of ​​the bracket mounting holes, so that the heat-affected zone of the weld points is separated from the bolt through holes. The bottom surface of the upper rear bumper bracket is in contact with the outer surface of the rear edge boss of the outer rear panel, and the bottom surface of the lower rear bumper bracket is attached to and fixed to the lower outer side of the inner rear panel.

[0007] As a further implementation, the rear lower bumper bracket is embedded in a pre-set U-shaped groove in the rear inner panel with an interference fit, and the U-shaped groove distributes the load borne by the rear lower bumper bracket to the rear longitudinal beam.

[0008] As a further implementation, it also includes a locking reinforcement plate, a nut box, and a nut plate. The locking reinforcement plate is fixed to the inner side of the rear inner panel by spot welding. The nut box is fixed to the locking reinforcement plate by spot welding. The nut plate is embedded in the nut box. A welded square nut is projected onto the nut plate and is located inside the nut box. A short-cycle arc-welded stud is also welded onto the rear inner panel.

[0009] As a further implementation, it also includes a left anchor ring fixing bracket, a right anchor ring fixing bracket, and a buffer block bracket, wherein the left anchor ring fixing bracket, the right anchor ring fixing bracket, and the buffer block bracket are all directly fixed to the rear inner plate by spot welding.

[0010] Secondly, the present invention also provides a vehicle body, characterized in that it includes a zero-switching compatible rear panel assembly and a rear floor assembly, wherein the rear floor assembly is either a rear floor assembly with a spare tire well or a rear floor assembly without a spare tire well; when the rear floor assembly is a rear floor assembly with a spare tire well, the inner side of the lower flange of the outer rear panel and the outer surface of the lower vertical section of the inner rear panel are provided with welding point areas, the inner side of the lower flange of the outer rear panel is spot-welded to the rear floor assembly with a spare tire well, and is connected to the front edge of the rear floor assembly with a spare tire well, and the rear floor assembly with a spare tire well is spot-welded to the outer surface of the lower vertical section of the inner rear panel, forming a double-interface spot-welded connection structure.

[0011] As a further implementation, when the rear floor assembly is a rear floor assembly without a spare tire pool, the outer surface of the lower vertical section of the rear inner panel is provided with a welding point area, and the outer surface of the lower vertical section of the rear inner panel is connected to the rear floor assembly without a spare tire pool by spot welding, forming a single-interface welding connection structure.

[0012] As a further implementation, a stepped sealing interface is provided in the overlapping area of ​​the rear outer panel and the rear floor assembly with spare tire pool. The stepped sealing interface is continuously arranged along the circumference of the spare tire pool to form a complete annular sealing channel. An R-angle transition area is provided at the corner of the stepped sealing interface. PVC sealant is continuously coated on the stepped sealing interface, and the PVC sealant is continuously arranged along the stepped sealing interface to form a sealing strip.

[0013] As a further implementation, a connecting plate is provided between the rear outer panel and the rear floor assembly without a spare tire well. Both the rear outer panel and the connecting plate are made of high-strength galvanized steel sheet. The rear outer panel has a boss structure corresponding to the overlapping area of ​​the connecting plate's flange. The boss structure and the connecting plate flange form a clearance fit. The overlapping area of ​​the upper and lower welding mating surfaces of the connecting plate is coated with double-layer PVC sealant. The through holes on the boss structure are filled with PVC sealant.

[0014] Thirdly, the present invention also provides a vehicle including the aforementioned vehicle body.

[0015] The beneficial effects of the present invention are as follows: The automotive rear panel assembly provided by this invention features a double-plate closed-cavity main load-bearing structure formed by multi-point resistance spot welding connecting the outer and inner rear panels. The weld points are evenly distributed in a checkerboard pattern along the inner edge of the outer rear panel and the corresponding overlapping surface of the inner rear panel, providing stable connection positions for floor assemblies with or without a spare tire well. This ensures uniform connection strength across the entire overlapping area, effectively avoiding localized stress concentration and improving overall load-bearing reliability. The edges of the outer and inner rear panels are completely enclosed to prevent the infiltration of external moisture and dust. The inner rear panel is equipped with transverse reinforcing ribs and longitudinal partitions, which, together with the outer rear panel, form a three-chamber closed structure, enabling lateral transfer of collision energy and buffering energy absorption. All functional components of the rear panel assembly are integrated onto the double-plate closed-cavity structure formed by the outer and inner rear panels. The entire assembly can be pre-assembled as an independent unit, forming a modular component with a complete structure and standard interfaces. This allows for adaptation to different rear floor assembly configurations with or without a spare tire well, achieving universal assembly across different vehicle platforms.

[0016] The vehicle body provided by this invention adopts the same rear bulkhead assembly compatible with both rear floor assembly configurations with and without a spare tire pool: For the configuration with a spare tire pool, dual-area welding points are simultaneously set on the inner side of the lower flange of the outer rear bulkhead and the outer surface of the lower vertical section of the inner rear bulkhead. The front edge of the rear floor assembly with the spare tire pool is connected to the inner side of the lower flange of the outer rear bulkhead and simultaneously connected to the outer surface of the lower vertical section of the inner rear bulkhead, forming a dual-interface spot-welded connection structure. The outer interface bears the lateral transmission of the spare tire's inertial load and collision energy, while the inner interface provides Z-axis rigid anchoring. The dual interfaces work together to significantly improve the overall connection stiffness and collision safety performance. For the configuration without a spare tire pool, all welding point areas on the side of the outer rear bulkhead are eliminated. The rear floor assembly without a spare tire pool is only connected to the outer surface of the lower vertical section of the inner rear bulkhead by spot welding, forming a single-interface welded connection structure. The aforementioned configuration-oriented structured reserved design eliminates the need to develop independent rear assembly assemblies for different configurations, fully demonstrating the platform-based versatility of the rear assembly and effectively reducing vehicle development costs and mold investment. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram of the overall structure of the rear enclosure assembly of the present invention; Figure 2 This is a schematic diagram of the rear outer panel structure of the present invention; Figure 3 This is a cross-sectional schematic diagram of the rear enclosure assembly of the present invention at the rear enclosure latch reinforcement plate; Figure 4 This is an exploded view of the rear assembly of the present invention; Figure 5 This is a schematic diagram of the welding and matching of the rear bulkhead assembly and the rear floor assembly with spare tire well of the present invention; Figure 6 This is a schematic diagram of the welding and matching of the rear bulkhead assembly and the rear floor assembly without a spare tire well in this invention; Figure 7 This is a schematic cross-sectional view of the rear floor matching the rear enclosure assembly of the present invention with and without a spare tire well.

[0019] The components include: 1. Rear outer panel; 2. Rear inner panel; 3. Rear bumper upper fixing bracket; 4. Anchor ring fixing bracket; 5. Rear buffer block bracket; 6. Rear bumper lower bracket; 7. Rear anti-collision beam mounting hole; 8. First weight reduction hole; 9. First positioning hole; 10. Second weight reduction hole; 11. Sill plate mounting hole; 12. Luggage box wheel cover fixing point; 13. Main positioning reference hole; 14. Tail sill mounting positioning hole; 15. Rear buckle reinforcement plate; 16. Short-cycle arc welding stud; 17. Second positioning hole; 18. Welded square nut; 19. Stepped sealing interface; 20. Rear floor assembly with spare tire pool; 21. Single interface; 22. Rear floor assembly without spare tire pool; 23. Rear outer panel boss. Detailed Implementation

[0020] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] Example 1 This embodiment provides a zero-switching compatible automotive rear panel assembly, consisting of two stamped plates: an outer rear panel 1 and an inner rear panel 2. The outer rear panel 1 and the inner rear panel 2 are connected by multi-point resistance spot welding to form a double-plate enclosed cavity main load-bearing structure. The weld points are evenly distributed in a checkerboard pattern along the inner edge of the outer rear panel 1 and the corresponding overlapping surface of the inner rear panel 2; that is, the weld points are arranged at equal intervals in both the horizontal and vertical directions, forming a regular matrix distribution pattern, with consistent spacing between adjacent weld points.

[0022] The checkerboard-like, evenly distributed weld point layout ensures uniform connection strength across the entire overlap area, avoiding stress concentration issues caused by localized weld point concentrations. This guarantees consistent overall load-bearing stiffness and maintains reliable panel connections under complex conditions such as collision loads and road vibration loads, effectively improving the overall load-bearing reliability of the rear assembly. The edges of the outer rear panel 1 and the inner rear panel 2 are completely enclosed after being flanged, forming a continuous, closed joint line. This effectively prevents external liquids and dust from seeping into the cavity through edge gaps, and prevents external moisture, dust, and noise from entering the vehicle body through these gaps, providing waterproof and dustproof protection for the sub-component installation areas within the cavity.

[0023] The rear outer panel 1 is made of cold-rolled hot-dip galvanized high-strength deep-drawing steel sheet, which can meet the process requirements of complex curved surface stamping of the rear outer panel 1. The cold rolling process gives it a uniform grain structure and stable mechanical properties. The hot-dip galvanizing treatment forms a continuous zinc-iron alloy protective layer on the surface of the sheet, providing reliable anti-corrosion protection throughout the entire life cycle of the vehicle.

[0024] The rear inner panel 2 is provided with transverse reinforcing ribs and longitudinal partitions. The transverse reinforcing ribs extend transversely along the rear inner panel 2, and the longitudinal partitions extend longitudinally along the rear inner panel 2. The transverse reinforcing ribs and longitudinal partitions intersect and cooperate with each other, together with the rear outer panel 1 to form a multi-chamber closed structure.

[0025] The multi-chamber enclosed structure is divided by transverse stiffeners and longitudinal partitions, forming an upper acoustic cavity, a middle load transfer cavity, and a lower buffer energy absorption cavity. The three chambers extend transversely and are segmented longitudinally by longitudinal partitions, creating a transversely continuous and longitudinally segmented spatial layout. The upper acoustic cavity is located in the upper region of the rear inner panel 2. Its cross-sectional shape and dimensions are designed according to the low-frequency noise insulation requirements of the vehicle interior. By utilizing the enclosed cavity to block the sound wave propagation path, it effectively attenuates low-frequency noise transmitted from the rear of the vehicle into the passenger compartment. The middle load transfer cavity is located in the middle region of the rear inner panel 2 and has a high moment of inertia. When subjected to rear-end collision loads, it can efficiently transfer collision energy laterally to the left and right side longitudinal beams and sill beams, achieving lateral dispersion of collision energy and reducing the risk of passenger compartment deformation. The lower buffer energy absorption cavity is located in the lower part of the rear inner panel 2. Its cross-sectional shape is designed to absorb collision energy in an orderly crushing manner after the collision load exceeds the design threshold, thereby reducing the peak collision load and reducing the impact force transmitted to the passenger compartment.

[0026] The upper rear bumper bracket 3 is fixed to the upper outer side of the rear outer panel 1 by resistance spot welding, and the lower rear bumper bracket 6 is fixed to the lower outer side of the rear inner panel 2 by resistance spot welding. Both the upper rear bumper bracket 3 and the lower rear bumper bracket 6 are provided with bracket mounting holes. These mounting holes are used to install the fixing bolts of the rear bumper assembly. The hole diameter and positional accuracy directly affect the installation accuracy and uniformity of the appearance gaps of the rear bumper.

[0027] The weld points on the upper rear bumper bracket 3 and the lower rear bumper bracket 6 are all located on the outer side of the corresponding bracket mounting holes, meaning the center of the weld point is located outward from the outer edge of the mounting hole, maintaining a sufficient safety distance between the weld point center and the outer edge of the mounting hole. This arrangement ensures sufficient isolation between the heat-affected zone of the weld and the bolt through-hole, guaranteeing that the heat-affected zone of the weld point completely avoids the bolt through-hole area. During resistance spot welding, the heat-affected zone formed around the weld point causes changes in the material's microstructure and mechanical properties. If the heat-affected zone extends to the edge of the bolt through-hole, it will cause thermal deformation of the material in the through-hole area, leading to deviations in the hole diameter. The accuracy of the bolt through-hole diameter directly affects the smoothness of bolt installation and the accuracy of the bolt tightening torque. Hole diameter deformation will make bolt installation difficult or even impossible, or cause deviations between the actual tightening torque and the design value, affecting the reliability of the bumper installation.

[0028] The bottom surface of the upper rear bumper bracket 3 forms a surface contact fit with the outer surface of the rear edge boss of the outer rear panel 1. The rear edge boss of the outer rear panel 1 is partially formed by shaping the outer rear panel 1, and the outer surface of the boss is a flat support reference surface. The bottom surface of the upper rear bumper bracket 3 is completely attached to the outer surface of the boss, eliminating the gap between the bottom surface of the bracket and the mounting base surface, preventing the bracket from warping and deforming when bearing the load of the bumper, providing a rigid support reference for the upper rear bumper bracket 3, and effectively improving the rigidity and positioning accuracy of the mounting point on the rear bumper. The bottom surface of the lower rear bumper bracket 6 is attached and fixed to the lower outer side of the inner rear panel 2, forming a surface contact connection relationship, ensuring that the surface contact connection between the bracket and the inner panel is stable and reliable, and providing a reliable load-bearing foundation for the lower rear bumper mounting point.

[0029] The rear bumper lower bracket 6 is inserted into a pre-set U-shaped groove in the rear inner panel 2 with a negative tolerance interference fit. The U-shaped groove extends laterally along the lower part of the rear inner panel 2, with a U-shaped cross-section, and the groove opening faces the insertion direction of the rear bumper lower bracket 6. The corresponding insertion part of the rear bumper lower bracket 6 has a slightly larger outer dimension than the opening size of the U-shaped groove. During insertion, it is forcibly pressed into the groove under pressure. After insertion, the outer wall of the rear bumper lower bracket 6 forms a tight mechanical contact with the two side walls and the bottom surface of the U-shaped groove, forming an integrated load-bearing structure. The contact pressure generated by the interference fit gives the rear bumper lower bracket 6 and the U-shaped groove a high frictional force. Combined with spot welding, this results in a connection rigidity higher than that of ordinary planar lap joints.

[0030] When the rear bumper is subjected to an impact load, the impact load is first transferred to the lower rear bumper bracket 6, and then laterally dispersed through the contact surface between the lower rear bumper bracket 6 and the side wall of the U-shaped groove. Simultaneously, it is transferred in the Z-direction through the contact surface between the lower rear bumper bracket 6 and the bottom surface of the U-shaped groove. The U-shaped groove distributes the load to a large area of ​​the rear inner panel 2, which then transfers the load to the rear longitudinal beam, ultimately bearing the load of the entire vehicle structure. This solves the problem in existing solutions where the overlap between the lower rear bumper bracket and the inner panel results in insufficient rigidity at the mounting point and difficulty in effectively distributing the bumper load to the rear longitudinal beam.

[0031] The rear door latch reinforcement plate 15 is spot-welded to the inner side of the rear door inner panel 2, and its installation position precisely corresponds to the stress area of ​​the tailgate latch. The impact load generated by the latch when the tailgate is closed, as well as the continuous dynamic load borne by the latch under driving vibration conditions, all act on this area. The rear door latch reinforcement plate 15 and the rear door inner panel 2, when stacked, form a composite plate structure that can jointly bear the impact force of the tailgate latch. The presence of the rear door latch reinforcement plate 15 increases the local section moment of inertia of the latch installation area, effectively preventing local bending deformation or fatigue failure of the rear door inner panel 2 in the latch stress area, ensuring the reliability of the latch function during long-term use. The edge of the rear door latch reinforcement plate 15 extends to the outer side of the latch installation area of ​​the rear door inner panel 2, ensuring that the reinforcement range covers the entire stress area.

[0032] The nut box is a three-dimensional stamped part, fixed to the rear latch reinforcement plate 15 by spot welding, forming a closed internal space between the nut box and the rear latch reinforcement plate 15. The nut plate is a flat part, embedded in the inner cavity of the nut box. The inner wall of the nut box constrains the nut plate, preventing displacement during use. After being embedded, the nut plate is constrained and fixed by the nut box. The welded square nut 18 is welded to the nut plate by projection welding. The welded square nut 18 is located inside the nut box, providing a reference for internal thread installation, used for bolt fastening of functional components such as the rear door latch assembly and hinges. The closed structure of the nut box isolates the welded square nut 18 from the external environment, effectively protecting it from corrosive media and extending its service life. At the same time, the rigid constraint of the nut box on the nut plate prevents the welded square nut 18 from loosening or displacement during repeated tightening, ensuring long-term reliable threaded connection.

[0033] The edge of the rear locking reinforcement plate 15 overlaps with the edge of the nut plate, so that the same weld point can connect the rear locking reinforcement plate 15 and the nut plate, thereby reducing the number of parts.

[0034] The short-cycle arc welding stud 16 is directly welded to the surface of the rear inner panel 2 using a short-cycle arc welding process. After welding, the short-cycle arc welding stud 16 forms a fixed post with external threads on the surface of the rear inner panel 2, providing a screw fixing point for external components, and is used for the installation and fixing of external components such as interior trim, wiring harness clips, pipe supports, and sound insulation cotton fixing parts.

[0035] One anchor ring fixing bracket 4 is installed on each side, and is directly fixed to the corresponding positions on the left and right sides of the rear inner panel 2 by spot welding. The number and arrangement of the welding points on the anchor ring fixing bracket 4 are optimized according to the force direction of the anchor ring. The welding points are evenly distributed along the normal direction of the force direction of the anchor ring to ensure that the force on each welding point is uniform and to avoid the failure of the welding point due to excessive load on a single welding point. The load borne by the anchor ring is transferred to the rear inner panel 2 through the anchor ring fixing bracket 4, then to the rear longitudinal beam, and finally borne by the entire vehicle structure.

[0036] The rear bumper block bracket 5 is directly fixed to the corresponding area of ​​the rear inner panel 2 by spot welding, and is used to install the tailgate bumper block. When the tailgate is closed, the bumper block first contacts the rear bumper block bracket 5. During the compression deformation process, the rubber of the bumper block absorbs the impact energy generated by the tailgate closing, reducing the impact force of closing the door and avoiding rigid collision between the tailgate and the rear of the vehicle body. In the closed state, the bumper block provides elastic support for the tailgate in an elastic compression state, preventing the tailgate from shaking and making abnormal noises under driving vibration conditions.

[0037] The center line of the weld point on the rear buffer block bracket 5 is perpendicular to the mounting surface of the buffer block bracket, that is, strictly perpendicular to the compression direction of the buffer block rubber. This ensures that the axial compressive load borne by the buffer block is directly transmitted to the inner rear panel 2 along the center line of the weld point. The load transmission is unbiased, avoiding uneven stress caused by the shear force component on the weld point, and effectively improving the installation reliability and service durability of the rear buffer block bracket 5.

[0038] The installation areas of the anchor ring fixing bracket 4 and the rear buffer block bracket 5 on the inner rear panel 2 do not overlap, and the installation areas of each bracket do not interfere with the installation areas of other brackets, ensuring the independence of each installation point and the clarity of the load transfer path. Both the anchor ring fixing bracket 4 and the rear buffer block bracket 5 are directly fixed to the inner rear panel 2 by spot welding, without transferring load through intermediate transition parts, resulting in a short load transfer path and high connection rigidity.

[0039] The rear bumper beam mounting holes 7 are located at both ends of the rear outer panel 1, allowing the rear bumper beam mounting bolts to pass through and be fixed in place. The diameter and position of the rear bumper beam mounting holes 7 match the rear bumper beam mounting interface, ensuring precise bolt installation and reliable fixing. The first weight reduction hole 8 is located at a non-primary load-bearing position on the rear outer panel 1 to achieve weight reduction. The shape, size, and position of the hole have been optimized through finite element structural analysis, effectively reducing the overall weight of the rear assembly while meeting structural strength requirements.

[0040] The rear door latch reinforcement plate 15 is disposed on the horizontal surface of the rear outer panel 1, and its installation position precisely corresponds to the stress area of ​​the tailgate latch. It is fixed to the inner side of the rear outer panel 1 by spot welding, and together with the rear outer panel 1, it bears the impact load generated by the tailgate latch under closing impact and driving vibration conditions, preventing local deformation failure of the rear outer panel 1 and improving the composite load-bearing capacity of the latch. The second positioning hole 17 is disposed on the horizontal surface of the rear outer panel 1 to improve the installation position accuracy of the rear assembly.

[0041] The inner rear panel 2 also has multiple functional holes and mounting structures. The first positioning hole 9 is located on the vertical surface of the inner rear panel 2, serving as an auxiliary positioning reference. Together with the second positioning hole 17 on the horizontal surface of the outer rear panel 1, it provides auxiliary positioning constraints for the rear assembly. The second weight reduction hole 10 is located in the non-load-bearing area of ​​the vertical surface of the inner rear panel 2. The hole shape was determined through structural analysis to achieve the weight reduction target while ensuring the load-bearing capacity of the inner rear panel 2 and avoiding stress concentration.

[0042] The door sill mounting holes 11 are located at both ends of the horizontal plane of the rear inner panel 2 for installing the door sill fixing bolts, reliably fixing the door sill to the end of the rear assembly, and closing the door sill cavity port. The diameter and position of the door sill mounting holes 11 match the installation interface of the door sill. The luggage compartment wheel cover fixing points 12 are located on the horizontal plane of the rear inner panel 2 for installing and fixing the luggage compartment side wheel covers. The position and structural strength of the fixing points are designed according to the load requirements of the wheel covers under vehicle vibration conditions to ensure reliable wheel cover installation without abnormal noise.

[0043] The rear sill mounting positioning hole 14 is set at the end of the horizontal plane of the rear inner panel 2. It is used for the precise positioning of the rear sill parts during installation, ensuring the assembly position accuracy between the rear sill and the rear assembly, and ensuring that the flatness of the rear sill surface after assembly meets the quality requirements of the whole vehicle.

[0044] The rear bumper lower bracket 6 is provided with a main positioning reference hole 13, which serves as the main positioning reference for the rear assembly. A positioning pin engages with the main positioning reference hole 13 to provide precise spatial positioning for the rear bumper lower bracket 6 and the connected rear inner panel 2. The main positioning reference hole 13, together with the first positioning hole 9 on the vertical surface of the rear inner panel 2 and the second positioning hole 17 on the horizontal surface of the rear outer panel 1, constitute the positioning reference. The main positioning reference hole 13 constrains the main translational and rotational degrees of freedom of the rear assembly, while the two secondary positioning holes constrain the remaining rotational degrees of freedom. The three-hole joint positioning ensures that all six degrees of freedom of the rear assembly are fully constrained during welding, effectively eliminating positional deviations of the rear assembly during welding, ensuring the welding position accuracy between the rear assembly and adjacent body parts, guaranteeing that the assembly clearance and surface difference between the rear assembly and the surrounding body structure meet design requirements, and ensuring the consistency of product dimensions in mass production.

[0045] Example 2 This embodiment provides a vehicle body, including the aforementioned rear bulkhead assembly and rear floor assembly.

[0046] The rear floor assembly 20 with a spare tire pool has a downwardly protruding spare tire pool in the center of the rear floor plane. The spare tire pool is used to accommodate a spare tire, and a complex three-dimensional curved transition area is formed around the spare tire pool. The connection between the rear bulkhead assembly and the rear floor assembly 20 with the spare tire pool must simultaneously meet multiple performance requirements such as structural rigidity and collision safety.

[0047] This embodiment employs a dual-interface welding connection scheme. Welding points are provided on the inner side of the lower flange of the rear outer panel 1 and on the outer surface of the lower vertical section of the rear inner panel 2. The leading edge of the rear floor assembly 20 with the spare tire well is spot-welded to the inner side of the lower flange of the rear outer panel 1, forming an outer welding interface. This interface bears the inertial load generated by the spare tire during vehicle operation and the lateral transmission of collision energy to the outside during a rear-end collision, dispersing the load from the spare tire well area to both sides of the vehicle structure through the rear outer panel 1. Simultaneously, the rear floor assembly 20 with the spare tire well is spot-welded to the outer surface of the lower vertical section of the rear inner panel 2, forming an inner welding interface. The dual interfaces work together to bear the load, and the outer and inner interfaces together constitute a high-rigidity connection structure.

[0048] A stepped sealing interface 19 is provided in the overlap area between the rear outer panel 1 and the rear floor assembly 20 with the spare tire tank. The complex three-dimensional curved surface around the spare tire tank causes the overlap gap between the two panels to vary circumferentially, making it difficult to ensure the continuity and uniformity of the sealant layer by direct adhesive application. The stepped sealing interface 19 transforms the complex three-dimensional curved surface of the overlap area into a controllable stepped cross-section. The step height is 8 to 9 mm, and the step width matches the overlap of the panels, providing a stable and regular geometric basis for sealant application. The stepped sealing interface 19 is continuously arranged circumferentially along the spare tire tank, forming a complete annular sealing channel, eliminating discontinuities in the sealing path, and ensuring the continuity and integrity of the seal.

[0049] The stepped sealing interface 19 features an R-angle transition zone at its corners to prevent sealant buildup and stress concentration at right-angle corners. Right-angle corners are prone to stress concentration under temperature cycling and vibration loads, leading to sealant layer cracking and failure. The R-angle transition zone ensures uniform stress distribution, guaranteeing even sealant distribution at the corners, improving the durability of the sealant layer at corners, preventing sealant cracking and failure due to stress concentration, and ensuring the long-term reliability of the sealing structure under vehicle-wide vibration conditions.

[0050] PVC sealant is evenly applied to the stepped sealing interface 19 using an automated robotic applicator. The resulting cross-section is semi-circular, and the sealant is applied continuously along the stepped sealing interface 19 to form a sealed strip. The stepped sealing interface 19 and the PVC sealant together constitute a multi-layered sealing barrier, effectively preventing liquid from seeping into the vehicle body and blocking dust and impurities from entering. Even if minor damage occurs to a local sealing layer, the remaining sealing layers can still maintain effective protection, significantly improving the overall sealing quality and durability of the vehicle.

[0051] The vehicle body of this embodiment includes a rear bulkhead assembly and a rear floor assembly 22 without a spare tire well. The rear floor assembly 22 without a spare tire well is a flat structure or a rear floor structure with ordinary storage compartments, without a downwardly protruding spare tire well, and the rear end edge is a flat or slightly curved overlapping surface, and the overlapping geometry with the rear bulkhead assembly is relatively simple.

[0052] The rear bulkhead assembly and the rear floor assembly 22 without a spare tire well adopt a single-interface 21 welding connection scheme. The rear floor assembly 22 without a spare tire well is connected to the outer surface of the lower vertical section of the rear bulkhead inner panel 2 only by resistance spot welding, forming a single-interface inner-side dominant welding connection structure. The weld points are linearly and evenly distributed along the rear edge of the rear floor assembly 22 without a spare tire well, and the overlap position is located on the outer surface of the lower vertical section of the rear bulkhead inner panel 2, that is, the side facing the interior of the carriage. In this embodiment, all weld point areas and corresponding adhesive surfaces on the side of the rear bulkhead outer panel 1 are eliminated, and only the single-interface 21 weld points and shortened adhesive surfaces on the side of the rear bulkhead inner panel 2 are retained, simplifying the connection process. The same rear panel assembly, through a configuration-oriented structured reserved design, simultaneously reserves all the welding areas and sealing surfaces required for both the configuration with and without a spare tire pool on the outer rear panel 1 and the inner rear panel 2. This achieves platform compatibility for the two rear floor assembly configurations, eliminating the need to develop independent rear panel assembly structures for different configurations and effectively reducing development costs and mold investment.

[0053] To address the gap control issue between the rear floor assembly 22 (without a spare tire tank) and the rear bulkhead assembly, a connecting plate is installed between the rear bulkhead outer panel 1 and the rear floor assembly 22 (without a spare tire tank). This connecting plate transition structure achieves a sealed connection. The connecting plate is made of high-strength galvanized steel sheet with a thickness of 1 mm. The planar shape of the connecting plate matches the overlapping area of ​​the rear bulkhead outer panel 1 and the rear floor assembly 22 (without a spare tire tank). The rear bulkhead outer panel 1 is also made of high-strength galvanized steel sheet. Since the connecting plate is made of the same material as the rear bulkhead outer panel 1, there is no electrochemical potential difference at their contact interface, fundamentally eliminating the risk of contact corrosion and ensuring long-term corrosion resistance in the overlapping area. The connecting plate has flanges on both the upper and lower sides. The upper flange overlaps with the corresponding area of ​​the rear bulkhead outer panel 1, and the lower flange overlaps with the corresponding area of ​​the rear floor assembly 22 (without a spare tire tank). The connecting plate acts as a transition component between the two, coordinating their geometric relationship.

[0054] The initial gap at the overlap area between the side flange of the connecting plate and the outer rear panel 1 is approximately 5.5 mm. This gap exceeds the effective sealing range of PVC sealant. If sealant is applied directly to this gap, it is prone to runoff due to gravity or vibration before curing, failing to form an effective adhesive bridge on both sides of the overlap interface, leading to seal failure. To solve the gap control problem, a rear panel boss 23 is provided at the position corresponding to the overlap area of ​​the connecting plate flange on the outer rear panel 1. The rear panel boss 23 is formed by locally stamping outward from the outer rear panel 1. The boss height is 1 mm, and the width of the boss matches the overlap width of the connecting plate flange. The edge of the boss has a rounded transition to avoid stress concentration at the edge of the boss. The rear outer panel protrusion 23 extends into the overlapping area of ​​the connecting plate flange, reducing the effective gap between the connecting plate flange and the rear outer panel 1 from the original 5.5 mm to 4.5 mm. This is controlled within the reasonable range for effective sealing of PVC sealant, preventing sealant loss due to excessive gaps and ensuring that the sealant can be fully wetted in the overlapping gap to form a continuous sealing layer. This fundamentally solves the problem of sealing failure caused by excessive gaps.

[0055] A double-coat PVC sealant process is used in the overlapping areas of the upper and lower welding surfaces of the connecting plate. Two coats of PVC sealant are applied to both the upper and lower overlapping surfaces of the connecting plate. These two sealants form a double sealing barrier on each overlapping surface of the connecting plate. Even if one sealant has a localized defect, the other sealant can still provide effective protection, significantly improving the reliability and durability of the sealing structure and ensuring stable and reliable sealing performance throughout the entire vehicle lifecycle. PVC sealant is also used to fill the through-holes on the rear bulkhead outer panel boss 23, ensuring a tight and smooth seal in the through-hole area and preventing liquids and dust from entering the vehicle body through the through-holes.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A zero-switching compatible automotive rear panel assembly, characterized in that, It includes an outer rear panel and an inner rear panel. The outer rear panel and the inner rear panel are connected by multi-point resistance spot welding to form a double-plate closed cavity main load-bearing structure. The weld points are evenly distributed in a checkerboard pattern along the inner side of the flange of the outer rear panel and the corresponding overlapping surface of the inner rear panel. The edges of the outer rear panel and the inner rear panel completely cover and close each other. The inner rear panel is provided with transverse reinforcing ribs and longitudinal partitions, which together with the outer rear panel form a multi-chamber closed structure. The multi-chamber closed structure consists of an upper acoustic cavity, a middle load transfer cavity, and a lower buffer energy absorption cavity.

2. The zero-switching compatible automotive rear assembly according to claim 1, characterized in that, It also includes an upper rear bumper bracket and a lower rear bumper bracket. The upper rear bumper bracket is fixed to the upper outer side of the outer rear panel by spot welding, and the lower rear bumper bracket is fixed to the lower outer side of the inner rear panel by spot welding. The upper and lower rear bumper brackets are also provided with bracket mounting holes. The weld points on the upper and lower rear bumper brackets are all arranged in the outer area of ​​the bracket mounting holes, so that the heat-affected zone of the weld points is separated from the bolt through holes. The bottom surface of the upper rear bumper bracket is in contact with the outer surface of the rear edge boss of the outer rear panel, and the bottom surface of the lower rear bumper bracket is attached to and fixed to the lower outer side of the inner rear panel.

3. The zero-switching compatible automotive rear assembly according to claim 2, characterized in that, The rear lower guard bracket is inserted into the U-shaped groove of the rear inner panel with an interference fit. The U-shaped groove distributes the load borne by the rear lower guard bracket to the rear longitudinal beam.

4. The zero-switching compatible automotive rear assembly according to claim 1, characterized in that, It also includes a locking reinforcement plate, a nut box, and a nut plate. The locking reinforcement plate is fixed to the inner side of the rear inner panel by spot welding. The nut box is fixed to the locking reinforcement plate by spot welding. The nut plate is embedded in the nut box. A welded square nut is projected onto the nut plate and is located inside the nut box. A short-cycle arc welded stud is also welded onto the rear inner panel.

5. A zero-switching compatible automotive rear assembly according to claim 1, characterized in that, It also includes a left anchor ring fixing bracket, a right anchor ring fixing bracket, and a buffer block bracket, all of which are directly fixed to the rear inner panel by spot welding.

6. A vehicle body, characterized in that, The invention includes a zero-switching compatible automotive rear panel assembly and a rear floor assembly as described in any one of claims 1-5, wherein the rear floor assembly is either a rear floor assembly with a spare tire well or a rear floor assembly without a spare tire well; when the rear floor assembly is a rear floor assembly with a spare tire well, the inner side of the lower flange of the outer rear panel and the outer surface of the lower vertical section of the inner rear panel are provided with welding point areas, the inner side of the lower flange of the outer rear panel is spot-welded to the rear floor assembly with a spare tire well, and is connected to the front edge of the rear floor assembly with a spare tire well, and the rear floor assembly with a spare tire well is spot-welded to the outer surface of the lower vertical section of the inner rear panel, forming a double-interface spot-welded connection structure.

7. A vehicle body according to claim 6, characterized in that, When the rear floor assembly is a rear floor assembly without a spare tire pool, the outer surface of the lower vertical section of the rear inner panel is provided with a welding point area, and the outer surface of the lower vertical section of the rear inner panel is connected to the rear floor assembly without a spare tire pool by spot welding, forming a single-interface welding connection structure.

8. A vehicle body according to claim 6, characterized in that, A stepped sealing interface is provided in the overlapping area of ​​the rear outer panel and the rear floor assembly with spare tire pool. The stepped sealing interface is continuously arranged around the spare tire pool to form a complete annular sealing channel. An R-corner transition area is provided at the corner of the stepped sealing interface. A sealant is continuously coated on the stepped sealing interface and the sealant is continuously arranged along the stepped sealing interface to form a sealing strip.

9. A vehicle body according to claim 7, characterized in that, A connecting plate is provided between the rear outer panel and the rear floor assembly without a spare tire well. Both the rear outer panel and the connecting plate are made of high-strength galvanized steel sheet. A boss structure is provided on the rear outer panel corresponding to the overlapping area of ​​the connecting plate flange. The boss structure and the connecting plate flange form a clearance fit. The overlapping area of ​​the upper and lower welding mating surfaces of the connecting plate is coated with double sealant. The through holes on the boss structure are filled with PVC sealant.

10. A vehicle, characterized in that, Including the vehicle body as described in claims 6-9.

Images