Vehicle body structure with improved roof crush resistance and vehicle

Abstract

The application discloses a vehicle body structure with improved compression resistance and a vehicle, and relates to the technical field of automobile body structures. The vehicle body structure comprises a front roof cross beam assembly and an inner door ring assembly. The front roof cross beam assembly and the inner door ring assembly are connected to form a frame transmission path in the shape of a Chinese character 'jia'. The inner door ring assembly comprises an inner door ring body. The inner door ring body is provided with a first reinforcing plate and a second reinforcing plate which are installed side by side in the bending area of a B column. The inner door ring body is provided with a third reinforcing plate which is installed in the bending area of an A column. The frame transmission path in the shape of a Chinese character 'jia' and the multiple reinforcing plates are matched to solve the problem that the force transmission path of the vehicle body structure in the prior art is damaged when the vehicle body structure bears the roof pressure, and the vehicle body load capacity is insufficient and cannot meet the requirements of the roof crush test of the American standard.

Description

Technical Field

[0001] This invention relates to the field of automotive body structure technology, and more particularly to a body structure and vehicle that improves the roof's resistance to pressure. Background Technology

[0002] The requirements of the US standard's roof crush test differ from the Chinese standard, which only tests one side of the vehicle. The US standard requires that after testing one side, the other side must be tested using the same method. In existing technology, the front roof crossbeam and its connecting plate are typically made of HC340 / 590DP material with a thickness of approximately 1.2mm. When subjected to roof crush, the front roof crossbeam and connecting plate experience significant stress and are prone to bending. This leads to displacement of the upper A-pillar beam inward, causing bending of the lower A-pillar and the middle of the B-pillar, resulting in glass breakage. Because the force transmission path resisting roof crush is disrupted after testing one side, the vehicle's ability to resist external forces is significantly reduced when the same load is applied to the other side under these conditions. The load-bearing capacity of the other side cannot meet the load requirement of three times the curb weight, leading to test failure. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to provide a vehicle body structure and vehicle that enhances top pressure resistance. By using a U-shaped frame force transmission path in conjunction with multiple reinforcing plates, the invention can solve the problem in existing technologies where the force transmission path of the vehicle body structure is damaged when subjected to top pressure, resulting in insufficient vehicle body load-bearing capacity and inability to meet the requirements of the US standard top pressure test.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, embodiments of the present invention provide a vehicle body structure for improving the roof's compressive strength, including a front roof crossbeam assembly and an inner door ring assembly, wherein the front roof crossbeam assembly and the inner door ring assembly are connected to form a U-shaped frame force transmission path; the inner door ring assembly includes an inner door ring body, wherein a first reinforcing plate and a second reinforcing plate are installed side by side in the bending area of ​​the B-pillar, and a third reinforcing plate is installed in the bending area of ​​the A-pillar.

[0005] As a further implementation, the second reinforcing plate is disposed on the front side of the first reinforcing plate; The first reinforcing plate consists of two plates arranged sequentially along the direction of the B-pillar, with a gap between the two plates.

[0006] As a further implementation, the distance between the third reinforcing plate and the vertex of the A-pillar is greater than the distance between the first and second reinforcing plates and the vertex of the B-pillar.

[0007] As a further implementation, the lengths of the first and second reinforcing plates are both greater than the length of the third reinforcing plate.

[0008] As a further implementation, the front top beam assembly is connected to the inner door ring body via a front top beam connecting plate.

[0009] As a further implementation, the first reinforcing plate, the second reinforcing plate, and the third reinforcing plate are of equal thickness and less than the thickness of the front top beam connecting plate.

[0010] As a further implementation, the first reinforcing plate, the second reinforcing plate, the third reinforcing plate, and the front top beam connecting plate are all made of hot-formed steel.

[0011] As a further implementation, the first reinforcing plate, the second reinforcing plate, and the third reinforcing plate are provided with an electrophoresis tank.

[0012] As a further implementation, the force transmission path of the U-shaped frame has a square cross-section.

[0013] Secondly, embodiments of the present invention also provide a vehicle including the aforementioned body structure.

[0014] The beneficial effects of this invention are as follows: This invention connects the front roof crossbeam assembly and the inner door ring assembly to form a U-shaped frame force transmission path, which transmits and distributes the top pressure to the A-pillar and B-pillar of the vehicle body. At the same time, a first and a second reinforcing plate are installed side by side in the bending area of ​​the B-pillar, and a third reinforcing plate is installed in the bending area of ​​the A-pillar. This provides targeted reinforcement to the bending risk areas of the inner door ring body, effectively preventing the force transmission path from bending failure under the top pressure load, reducing the deformation of the passenger compartment, and enabling the vehicle body to meet the test requirements of the roof bearing a load of three times the curb weight, thereby passing the US standard roof pressure test requirements. Attached Figure Description

[0015] 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.

[0016] Figure 1 This is a schematic diagram of the assembly state of the front top crossbeam assembly and the inner door ring assembly according to one or more embodiments of the present invention; Figure 2 This is a schematic diagram of the front top crossbeam assembly and inner door ring assembly in separate states according to one or more embodiments of the present invention; Figure 3 This is a schematic diagram of the installation of the reinforcing plate and the inner door ring body according to one or more embodiments of the present invention; Figure 4 This is a schematic diagram of the first reinforcing plate structure according to one or more embodiments of the present invention; Figure 5This is a schematic diagram of the second reinforcing plate structure according to one or more embodiments of the present invention; Figure 6 This is a schematic diagram of the third reinforcing plate structure according to one or more embodiments of the present invention.

[0017] Among them, 1-front roof crossbeam assembly, 2-inner door ring assembly, 3-A pillar, 4-B pillar; 21-Inner door ring body, 22-First reinforcing plate, 23-Second reinforcing plate, 24-Third reinforcing plate, 25-Front top beam connecting plate. Detailed Implementation

[0018] 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.

[0019] For ease of description, the terms "front," "rear," "left," and "right" appearing in this invention only indicate that they correspond to the front, rear, left, and right directions of the accompanying drawings themselves. They do not limit the structure and are merely used to facilitate the description of the invention and to simplify the description. They do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] Example 1: The core difference between the US standard roof crush test regulation (FMVSS 216) and the Chinese standard lies in the fact that the Chinese standard only requires a roof crush test on one side of the vehicle, while the US standard requires that after completing the test on one side, the other side must be tested again using the same method and load. This difference means that the vehicle body structure not only needs to have sufficient initial load-bearing capacity, but also must be able to resist the load applied to the other side after experiencing roof crush damage on one side, placing higher demands on the overall strength of the vehicle body structure and the integrity of the force transmission path.

[0021] In the prior art, the front roof cross member of the vehicle body and its connection plate are usually made of HC340 / 590DP dual-phase steel with a material thickness of about 1.2mm. The yield strength of HC340 / 590DP dual-phase steel is about 340MPa, and the tensile strength is about 590MPa. When bearing concentrated top pressure, the front roof cross member and the connection plate are subjected to relatively large forces, the material strength margin is insufficient, and plastic deformation or even fracture easily occurs in the bending zone, which further causes the upper side beam of the A-pillar to displace towards the inside of the vehicle, the lower part of the A-pillar and the middle part of the B-pillar are subsequently bent, and the glass breaks due to the deformation of the frame. Since the force transmission path for resisting top pressure has been damaged after a test on one side, when the same load is applied to the other side in this state, the ability of the vehicle body to resist external forces decreases significantly, and the load-bearing capacity of the other side cannot meet the load requirement of three times the curb weight, leading to test failure.

[0022] In view of the above problems, this embodiment provides a vehicle body structure that improves top pressure resistance. By constructing a jie-shaped frame force transmission path in the force-bearing area at the top of the vehicle body, the materials of the front roof cross member assembly 1 and the front roof cross member connection plate 25 are upgraded to high-strength hot-formed steel, and a plurality of hot-formed steel reinforcing patches are added in the bending risk area of the inner door ring body 21, so as to improve the top pressure resistance of the vehicle body.

[0023] With reference to Figure 1 and Figure 2 , the vehicle body structure of this embodiment includes a front roof cross member assembly 1 and inner door ring assemblies 2. The front roof cross member assembly 1 is arranged at the front part of the roof along the transverse direction of the vehicle body, the inner door ring assemblies 2 are arranged on both sides along the lateral direction of the vehicle body, and both ends of the front roof cross member assembly 1 are respectively connected with the inner door ring assemblies 2 on the left and right sides, thereby forming a jie-shaped frame force transmission path in the force-bearing area at the top of the vehicle body. The "jie-shaped" means that the front roof cross member assembly 1 is transversely arranged on the roof and connected with the longitudinally arranged inner door ring assemblies 2 on the left and right sides, and the whole forms a spatial frame shape similar to the Chinese character "jie" in the top view direction.

[0024] When the top pressure loading device applies a downward concentrated pressure to the roof, the pressure first acts on the front roof cross member assembly 1; as the first force-bearing member, the front roof cross member assembly 1 transmits the pressure to both ends along the axial direction of the cross member. Since both ends of the front roof cross member assembly 1 are reliably connected to the inner door ring assemblies 2 on the left and right sides respectively, the pressure is transmitted from both ends of the cross member into the inner door ring assemblies 2, and then transmitted downward through the inner door ring assemblies 2 along the A-pillar 3 and the B-pillar 4 to the bottom structure of the vehicle body. Through the above force transmission path, the concentrated top load is converted into a distributed load along the vehicle body frame, which effectively avoids local bending failure caused by the load being concentrated on a single member, and fundamentally protects the structural integrity of the passenger compartment.

[0025] In this embodiment, the front top beam assembly 1 and the inner door ring assembly 2 form a continuous and uninterrupted force transmission frame, so that stress concentration will not occur due to path interruption during load transmission; the top pressure is not only directly transmitted to the inner door ring assembly 2 through the front top beam assembly 1, but also the spatial rigidity constraint of the U-shaped frame allows the pressure to be evenly distributed within the frame, reducing the peak force of any single section; the inner door ring assemblies 2 on the left and right sides are symmetrically arranged, so that when one side is under pressure, the other side of the frame also participates in bearing the load, forming an overall synergistic effect to resist external forces.

[0026] Furthermore, the force transmission path of the U-shaped frame has a U-shaped cross-section, meaning that the cross-sections of each component along the force transmission path form a closed U-shape. A U-shaped cross-section refers to a component whose cross-section is a closed rectangle or approximately rectangular ring, with a closed cavity inside and continuous plates surrounding the cross-section without any openings. The moment of inertia of a closed cross-section is much greater than that of an open cross-section with the same amount of material. Under the same bending moment, the maximum bending stress and deformation of the closed cross-section are smaller. Moreover, the mutual constraints between the plates in the closed cross-section reduce the free length of individual plates, increase the local buckling critical stress of the plates, and effectively prevent bending failure caused by local instability of the cross-section.

[0027] The realization of the U-shaped cross-section requires the following conditions to be met: the components on each force transmission path must maintain complete force transmission ribs, and the ribs must be smoothly oriented without abrupt bends or sharp turns. Smooth rib orientation means that the neutral axis of the cross-section extends smoothly along the length of the component, without sharp turns or abrupt changes in the cross-section, ensuring that the load can be smoothly transmitted along the axial direction of the cross-section and avoiding stress concentration caused by abrupt changes in the cross-section.

[0028] Reference Figure 2 The front top crossbeam assembly 1 includes a front top crossbeam and a projection weld nut. The projection weld nut is connected to the front top crossbeam through a projection welding process, which is used to realize the bolt connection and fixation of the front top crossbeam assembly 1 to other components of the vehicle body, and to ensure the installation reliability and positional accuracy of the front top crossbeam assembly 1 in the vehicle body frame.

[0029] In this embodiment, the front top crossbeam is made of hot-formed steel CR950 / 1300HS with a thickness of 1.4mm. Hot-formed steel CR950 / 1300HS is an ultra-high-strength steel produced through a hot stamping process. Its tensile strength ranges from a minimum of 950MPa to a maximum of 1300MPa, and its yield strength is typically above 650MPa, exhibiting significant strength advantages compared to traditional cold-rolled high-strength steel. The hot-forming process involves heating the steel sheet to its austenitizing temperature (typically 880℃ to 950℃), rapidly transferring it to a mold at this high temperature for stamping, and simultaneously using a cooling system within the mold to rapidly quench and cool the formed part, transforming the steel sheet's microstructure into martensite, thereby achieving ultra-high strength and hardness. After hot forming, the part exhibits a uniform microstructure and stable strength, enabling high structural load-bearing capacity even with relatively thin material thicknesses.

[0030] Since the tensile strength of HC340 / 590DP duplex steel is approximately 590 MPa, while the minimum tensile strength of hot-formed steel CR950 / 1300HS is 950 MPa, this embodiment improves the strength of the front top beam. Furthermore, the material thickness is increased from 1.2 mm to 1.4 mm, resulting in a corresponding increase in the moment of inertia of the section, further enhancing the bending load-bearing capacity of the front top beam. This dual improvement in material strength and thickness significantly reduces the deformation of the front top beam under top pressure, effectively resisting the applied load and preventing bending failure during top pressure, thus protecting the integrity of the force transmission path.

[0031] Reference Figure 2 and Figure 3 The inner door ring assembly 2 includes an inner door ring body 21, a first reinforcing plate 22, a second reinforcing plate 23, a third reinforcing plate 24, and a front top beam connecting plate 25. The front top beam assembly 1 is connected to the inner door ring body 21 through the front top beam connecting plate 25, thereby realizing a reliable force transmission connection between the front top beam assembly 1 and the inner door ring assembly 2.

[0032] One end of the front top crossbeam connecting plate 25 overlaps with the end of the front top crossbeam assembly 1 and is connected by welding, while the other end overlaps with the top area of ​​the inner door ring body 21 and is fixed by welding, forming a force transmission bridge between the front top crossbeam assembly 1 and the inner door ring assembly 2. The cross-sectional shape and size of the front top crossbeam connecting plate 25 must match the end cross-section of the front top crossbeam and the top cross-section of the inner door ring body 21 to ensure a smooth transition at the connection node and to avoid stress concentration points.

[0033] In this embodiment, the front top beam connecting plate 25 is made of hot-formed steel CR950 / 1300HS with a thickness of 1.4mm, maintaining the same material strength and thickness as the front top beam. This is because the load-bearing capacity of the force transmission path depends on the weakest link in the path. If the material strength or thickness of the front top beam connecting plate 25 is lower than that of the front top beam, the connection node area will become a weak point in the force transmission path, preferentially experiencing bending failure under top pressure load, leading to interruption of the force transmission path. This embodiment ensures that the load-bearing capacity of the connection node area is not lower than that of the beam body by maintaining the same material and thickness as the front top beam, thereby ensuring uniform load-bearing throughout the entire force transmission path and preventing the node area from becoming a weak link.

[0034] Reference Figure 1 and Figure 3 The inner door ring body 21 has a first reinforcing plate 22 and a second reinforcing plate 23 installed side by side in the bending area of ​​the B-pillar 4. According to the view direction, the first reinforcing plate 22 is located behind the second reinforcing plate 23. The bending area of ​​the B-pillar 4 is the area where the inner door ring assembly 2 is most prone to bending failure under top pressure load. Its location corresponds to the area near the intersection of the middle part of the B-pillar 4 and the upper side beam. This area bears a large bending moment and shear force during the top pressure load transmission process and is a key weak node on the force transmission path.

[0035] Reference Figure 3 and Figure 5 The second reinforcing plate 23 is arranged close to the B-pillar 4 bending area of ​​the inner door ring body 21, with its large surface fitting against the large surface of the inner door ring body 21 and fixed by welding. The main function of the second reinforcing plate 23 is to increase the cross-sectional thickness of the B-pillar 4 bending area, increase the cross-sectional moment of inertia of this area, thereby improving the local bending strength and preventing the inner door ring body 21 from forming a plastic hinge in the bending area. The length of the second reinforcing plate 23 covers the main stress range of the B-pillar 4 bending area, ensuring effective reinforcement of the bending risk area.

[0036] The first reinforcing plate 22 is located behind the second reinforcing plate 23, and is arranged side by side with the second reinforcing plate 23 in the bending area of ​​the B-pillar 4. (Refer to...) Figure 3 and Figure 4 The first reinforcing plate 22 consists of two plates arranged sequentially along the direction of B-pillar 4. The two plates are arranged vertically along the extension direction of B-pillar 4, and together cover the stress range of the bending area of ​​B-pillar 4.

[0037] The first reinforcing plate 22 adopts a split design of two plates rather than a single integral plate. This is because the geometry of the B-pillar 4 bending area is relatively complex, with curvature changes along the B-pillar 4 direction. A single integral plate would be difficult to completely fit the large surface of the inner door ring body 21. The split design of two plates can adapt to the curvature of different sections, ensuring good fit between the large surface of each plate and the inner door ring body 21, thus improving the reliability of the welded connection. Furthermore, the split plate design facilitates the formation of an appropriate gap between the two plates, allowing the electrophoretic coating liquid to enter the gap between the mating surfaces, improving the anti-corrosion effect. The dividing position of the two plates can be optimized according to the stress distribution of the B-pillar 4 bending area, so that each plate accurately covers the section with the highest stress concentration, achieving more targeted local reinforcement.

[0038] In this embodiment, the first reinforcing plate 22 and the second reinforcing plate 23 are arranged side by side, jointly providing double reinforcement to the bending risk area of ​​the B-pillar 4. After the inner door ring body 21 is superimposed with the first reinforcing plate 22 and the second reinforcing plate 23, the effective cross-sectional thickness and moment of inertia of the bending area of ​​the B-pillar 4 are significantly increased, and the local bending strength is significantly enhanced. The first reinforcing plate 22 and the second reinforcing plate 23 effectively reinforce the force transmission path in the bending area of ​​the B-pillar 4. Even if the inner door ring body 21 undergoes slight local deformation under top pressure load, the plates can still maintain the overall integrity of the cross-section and prevent the force transmission path from being interrupted in the bending area.

[0039] Reference Figure 3 The lengths of the first reinforcing plate 22 and the second reinforcing plate 23 are both greater than the length of the third reinforcing plate 24. This is because the top pressure load transmission path of the B-pillar 4 bending area is relatively long, requiring a larger coverage area of ​​the plate to disperse stress concentration and ensure that the bending risk area is adequately reinforced.

[0040] Furthermore, the edges of the first reinforcing plate 22 and the second reinforcing plate 23 are provided with a flange structure. The flange overlaps with the corresponding edge of the inner door ring body 21 and is fixed by welding, which further enhances the reliability of the connection. At the same time, the flange structure helps to improve the local stiffness of the edge of the plate and prevents the edge from curling and deforming under stress.

[0041] Reference Figure 3 The inner door ring body 21 is fitted with a third reinforcing plate 24 in the bending area of ​​the A-pillar 3. The distance between the third reinforcing plate 24 and the apex of the A-pillar 3 is greater than the distance between the first reinforcing plate 22 and the second reinforcing plate 23 and the apex of the B-pillar 4. Specifically, the bending moment distribution of the A-pillar 3 under top pressure load varies along the column height, and the peak bending moment usually occurs in the lower middle part of the A-pillar 3, rather than at the top. Therefore, the installation position of the third reinforcing plate 24 is lower than the apex of the A-pillar 3, accurately covering the area of ​​the A-pillar 3 with the highest bending risk, ensuring that the installation position of the plate is adapted to the actual stress distribution, and achieving the optimal reinforcement effect.

[0042] If the installation position of the third reinforcing plate 24 is set too close to the vertex of column A 3, the plate will not be able to cover the peak bending moment area and will not achieve effective reinforcement. If the installation position is set too low, the stress level in the area covered by the plate will be relatively low, the reinforcement effect of the plate will not be fully utilized, and unnecessary weight will be added.

[0043] Reference Figure 6 The third reinforcing plate 24 is a slightly curved strip with a relatively wider end. Its overall outline conforms to the geometry of the A-pillar 3 bending area, ensuring that the plate fully fits the A-pillar area of ​​the inner door ring body 21. The surface of the third reinforcing plate 24 has three perforated structures spaced along its length, including two circular recesses with internal holes and one elliptical recess. These perforated structures serve as both electrophoresis tanks and weight-reduction holes: as electrophoresis tanks, they form a channel for electrophoretic coating liquid flow between the plate and the inner door ring body 21, ensuring corrosion resistance; as weight-reduction holes, they reduce the plate's weight while ensuring the structural strength meets local reinforcement requirements, thus complying with vehicle lightweighting requirements.

[0044] The edge of the third reinforcing plate 24 is also provided with a flange structure. The flange overlaps with the A-pillar 3 area of ​​the inner door ring body 21 and is fixed by welding to ensure the reliability of the connection between the third reinforcing plate 24 and the inner door ring body 21.

[0045] Furthermore, in this embodiment, the first reinforcing plate 22, the second reinforcing plate 23, and the third reinforcing plate 24 have equal thicknesses, and all are less than the thickness of the front top crossbeam connecting plate 25. Specifically, the thickness of the three reinforcing plates is 1.2 mm, and the thickness of the front top crossbeam connecting plate 25 is 1.4 mm.

[0046] Since the purpose of the reinforcing plate is to locally strengthen the bending risk area of ​​the inner door ring body 21 by increasing the thickness of the local section to improve the bending strength of the area, rather than replacing the inner door ring body 21 to bear the entire load, the thickness of the reinforcing plate does not need to be consistent with that of the connecting plate. Moreover, the 1.2mm thickness, combined with the high strength characteristics of hot-formed steel CR950 / 1300HS, can effectively control the weight of the reinforcing plate while meeting the local reinforcement strength requirements, taking into account the vehicle body's lightweight requirements, and avoiding the impact on the overall vehicle performance due to excessive weight increase.

[0047] The front top crossbeam connecting plate 25 is a node connector on the force transmission path, directly bearing the axial pressure and bending moment transmitted from the front top crossbeam assembly 1. Its stress strength is higher than that of the bending zone reinforcement plate, requiring a larger material thickness to ensure the load-bearing capacity of the node area and prevent the node from becoming a weak link in the force transmission path. The reinforcement plate is arranged in a local area of ​​the bending zone of the inner door ring body 21, mainly to increase the local section moment of inertia and prevent local bending. The load it bears is relatively small, and a material thickness of 1.2mm is sufficient to meet the reinforcement requirements.

[0048] In this embodiment, the first reinforcing plate 22, the second reinforcing plate 23, the third reinforcing plate 24, and the front top crossbeam connecting plate 25 are all made of hot-formed steel CR950 / 1300HS. Hot-formed steel has the significant characteristics of high strength and high hardness, and its martensitic structure endows the material with excellent tensile strength and yield strength. After hot stamping, the parts have a uniform structure, stable strength, and good consistency in performance of each part, without the local strength difference problem caused by uneven work hardening of cold-formed parts. Hot-formed steel can achieve high structural load-bearing capacity with relatively thin material thickness, meeting the strength requirements of local reinforcement in the bending area, while effectively controlling the weight of the parts.

[0049] In this embodiment, electrophoresis tanks are provided on the first reinforcing plate 22, the second reinforcing plate 23, and the third reinforcing plate 24. Each reinforcing plate is designed to fit as closely as possible to the main surface of the inner door ring body 21 to improve the reliability of the welded connection and the force transmission effect. However, the larger the contact area, the smaller the gap between the two plates, making it more difficult for the electrophoretic coating liquid to penetrate the gap between the contact areas. This results in poor corrosion protection in the contact area, and long-term use may affect the structural strength and service life due to corrosion of the contact area.

[0050] The electrophoresis tank is a shallow groove structure stamped onto the surface of the reinforcing plate. Its function is to create a flow channel for the electrophoretic coating liquid between the reinforcing plate and the inner door ring body 21, allowing the coating to smoothly enter the gap between the bonding surfaces and form a complete electrophoretic coating in the bonding area, ensuring the anti-corrosion effect. The position and number of electrophoresis tanks are rationally arranged according to the size and shape of the bonding surfaces to ensure that the electrophoretic coating liquid can evenly cover the entire bonding area.

[0051] It is particularly important to note that the electrophoresis tank should not be a through-type groove connecting the bottom and sides. A through-type groove refers to a groove that runs from the bottom surface of the reinforcing plate (the surface that contacts the inner door ring body 21) to the side surface of the plate, forming a continuous channel connecting the two surfaces. If a through-type groove is created, an opening will be formed in the cross-section of the reinforcing plate, turning a closed section into an open one, resulting in a significant decrease in the bending and torsional stiffness of that section. Therefore, the electrophoresis tank must be designed as a shallow, non-through groove, forming a channel for the coating liquid to flow only within the contact surface, without compromising the sealing and integrity of the reinforcing plate's cross-section, thus maintaining the structural strength of the reinforcing plate while ensuring the anti-corrosion effect.

[0052] The aforementioned reinforcing plates and front top crossbeam connecting plate 25 are connected to the inner door ring body 21 by welding to form a complete inner door ring assembly 2. The weld points should be evenly distributed around the perimeter of the reinforcing plates, and the spacing between weld points should be reasonably determined according to the plate size and stress requirements to ensure a uniform and reliable connection between the plates and the inner door ring body 21. Since hot-formed steel CR950 / 1300HS is an ultra-high-strength steel, its weldability is lower than that of ordinary high-strength steel. Therefore, it is necessary to strictly control the welding heat input during welding to avoid softening of the heat-affected zone and reducing the strength of the connection. The welding sequence should follow the principle of from the center outwards to reduce welding deformation and ensure the fitting accuracy between the reinforcing plates and the inner door ring body 21.

[0053] In this embodiment, the front top crossbeam assembly 1 and the inner door ring assembly 2 together form a U-shaped frame force transmission path, through which the top pressure is transmitted to the A-pillar 3 and B-pillar 4 of the vehicle body, thereby dispersing the top pressure. The components on each force transmission path maintain complete force transmission ribs, and the ribs have smooth directions without abrupt bends or bending points. Each force transmission path is made into a closed U-shaped cross section to ensure that the force transmission path does not bend or fail under top pressure load.

[0054] The U-shaped frame force transmission path transforms the concentrated load at the top into a distributed load along column A3 and column B4, effectively reducing the peak stress of any single component and preventing local bending failure. The U-shaped closed section provides high bending and torsional stiffness, ensuring the structural stability of the force transmission path under top pressure load. The front top beam and front top beam connecting plate 25 are made of high-strength hot-formed steel CR950 / 1300HS with a thickness of 1.4mm, which greatly improves the material strength and cross-sectional bearing capacity, and significantly reduces the deformation when subjected to top pressure. The targeted reinforcement of the first reinforcing plate 22 and the second reinforcing plate 23 in the bending area of ​​column B4 and the third reinforcing plate 24 in the bending area of ​​column A3 effectively prevents the inner door ring body 21 from forming a plastic hinge in the bending risk area, maintaining the integrity of the force transmission path.

[0055] Based on the above structure, after the body structure completes the top-pressure test on one side, the force transmission path can still remain basically intact, the deformation of the A-pillar 3 and B-pillar 4 areas is controlled within a small range, the glass damage range is small, and under the premise that the glass sealant does not fail, after applying pressure to the other side, the body can fully resist external forces, reduce the deformation of the passenger compartment, improve safety, and meet the test requirements of the roof bearing a load of three times the curb weight, thus meeting the US standard top-pressure test requirements.

[0056] Example 2: This embodiment provides a vehicle, including the body structure as described in Embodiment 1.

[0057] The core requirement of the FMVSS 216 standard is that the vehicle roof must be able to withstand a static load of at least three times the vehicle's curb weight, and tests must be conducted on both sides of the vehicle. The test method involves applying a rigid loading device at a specific angle to the front of the roof, applying the load at a specified rate until a target load of three times the curb weight is reached, and measuring the deformation of the roof under this load. The deformation must not exceed a specified limit. After completing the test on one side, the other side is tested again using the same method and the same target load. Therefore, the vehicle body structure must not only possess sufficient load-bearing capacity in its initial state but also effectively resist the same load applied to the other side after experiencing damage from one side's roof pressure. This places extremely high demands on the overall strength of the vehicle body structure and the continued integrity of the force transmission path.

[0058] During the actual roof crush test, when the loading device applies pressure to one side of the roof, the pressure is first transmitted through the roof skin to the front roof crossbeam assembly 1, then through the U-shaped frame force transmission path to the inner door ring assembly 2, and finally distributed to the A-pillar 3 and B-pillar 4. In this process, the front roof crossbeam assembly 1 bears the greatest bending moment and axial pressure, while the bending areas of A-pillar 3 and B-pillar 4 bear a large bending moment, making them the areas with the most concentrated stress along the entire force transmission path. If any component in the force transmission path fails due to bending, the cross-sectional load-bearing capacity of that component decreases sharply, the force transmission path is interrupted, the load cannot continue to be transmitted downwards, and the top of the passenger compartment will undergo significant intrusion deformation, resulting in test failure.

[0059] The vehicle in this embodiment adopts the body structure described in Embodiment 1. The top pressure is distributed to the A-pillar 3 and B-pillar 4 via a U-shaped frame force transmission path, effectively reducing the risk of top load intrusion into the passenger compartment. During the one-sided top pressure test, the front roof crossbeam assembly 1, made of high-strength hot-formed steel CR950 / 1300HS with a thickness of 1.4mm, exhibits significantly improved material strength. This results in a significant reduction in deformation under top pressure, preventing bending failure of the front roof crossbeam and maintaining the integrity of the transverse components of the force transmission path. The inner door ring assembly 2 has a first reinforcing plate 22 and a second reinforcing plate 23 arranged side-by-side in the bending area of ​​B-pillar 4, and a third reinforcing plate 24 in the bending area of ​​A-pillar 3. Each reinforcing plate is made of hot-formed steel CR950 / 1300HS with a thickness of 1.2mm, effectively reinforcing the bending risk area of ​​the inner door ring body 21 and preventing localized failure of the bending area under top pressure load. This ensures that the body structure maintains a high load-bearing capacity after the one-sided test is completed.

[0060] After completing the one-sided top-compression test, the deformation of the A-pillar 3 and B-pillar 4 areas was kept within a small range due to the intact force transmission path, resulting in minimal glass damage. Provided the glass sealant did not fail, the overall stiffness loss of the vehicle body structure was limited. When the same load was applied to the other side, the vehicle body could still adequately withstand external forces, meeting the test requirement of a load three times the curb weight, and successfully passing the US standard top-compression test on both sides.

[0061] The vehicle in this embodiment significantly improves the load-bearing capacity of the roof through the force transmission path of the U-shaped frame and the combination of multiple reinforcing plates, effectively reducing the intrusion of the passenger compartment roof in rollover accidents, providing passengers with a larger survival space, and significantly improving the passive safety performance of the vehicle.

[0062] Furthermore, this embodiment of the vehicle body structure, while enhancing the roof's load-bearing capacity, effectively controls the increase in vehicle weight through reasonable material selection and structural optimization. The reinforcing plates utilize hot-formed steel CR950 / 1300HS, achieving a high-strength reinforcement effect with a relatively thin material thickness of 1.2mm. Compared to solutions that require a greater material thickness to achieve the same reinforcement effect using ordinary high-strength steel, this embodiment exhibits a more limited increase in weight, aligning with the trend of automotive lightweighting. The structural reinforcement will not significantly impact the vehicle's fuel economy or the electric vehicle's driving range.

[0063] The vehicles in this embodiment include, but are not limited to, various types of motor vehicles such as passenger cars, SUVs, and MPVs.

[0064] In summary, the vehicle in this embodiment, based on the body structure described in Embodiment 1, effectively improves the passive safety performance of the entire vehicle while meeting the requirements of the US standard top crush regulation (FMVSS 216), providing more reliable safety protection for occupants.

[0065] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A vehicle body structure for improving the roof's resistance to pressure, characterized in that, It includes a front roof crossbeam assembly and an inner door ring assembly. The front roof crossbeam assembly and the inner door ring assembly are connected to form a U-shaped frame force transmission path. The inner door ring assembly includes an inner door ring body. The inner door ring body has a first reinforcing plate and a second reinforcing plate installed side by side in the bending area of ​​the B-pillar. The inner door ring body has a third reinforcing plate installed in the bending area of ​​the A-pillar.

2. The vehicle body structure for improving top pressure resistance according to claim 1, characterized in that, The second reinforcing plate is located in front of the first reinforcing plate; The first reinforcing plate consists of two plates arranged sequentially along the direction of the B-pillar, with a gap between the two plates.

3. A vehicle body structure for improving top pressure resistance according to claim 1 or 2, characterized in that, The distance between the third reinforcing plate and the top of the A-pillar is greater than the distance between the first and second reinforcing plates and the top of the B-pillar.

4. A vehicle body structure for improving top pressure resistance according to claim 3, characterized in that, The lengths of the first and second reinforcing plates are both greater than the length of the third reinforcing plate.

5. A vehicle body structure for improving top pressure resistance according to claim 1, characterized in that, The front top crossbeam assembly is connected to the inner door ring body via the front top crossbeam connecting plate.

6. A vehicle body structure for improving top pressure resistance according to claim 5, characterized in that, The first, second, and third reinforcing plates have the same thickness, and are less than the thickness of the front top beam connecting plate.

7. A vehicle body structure for improving top pressure resistance according to claim 5 or 6, characterized in that, The first reinforcing plate, the second reinforcing plate, the third reinforcing plate, and the front top beam connecting plate are all made of hot-formed steel.

8. A vehicle body structure for improving top pressure resistance according to claim 1 or 2, characterized in that, The first reinforcing plate, the second reinforcing plate, and the third reinforcing plate are fitted with an electrophoresis tank.

9. A vehicle body structure for improving top pressure resistance according to claim 1, characterized in that, The force transmission path of the U-shaped frame has a square cross-section.

10. A vehicle, characterized in that, Includes the vehicle body structure as described in any one of claims 1-9.

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