Flexible collision-resistant vehicle body structure, auxiliary frame front end energy absorption assembly and vehicle configuration method

Abstract

The invention discloses a flexible collision-resistant vehicle body structure, an auxiliary frame front end energy absorption assembly and a vehicle configuration method. The structure comprises a basic body frame and a reinforcing assembly. Wherein the upper longitudinal beam connection reinforcing piece adopts a four-plate tailor-welded structure and is arranged between the front section of the front longitudinal beam and the front cabin upper longitudinal beam, and a front connecting plate, a rear connecting plate and a lower connecting plate of the upper longitudinal beam connection reinforcing piece are welded with the front longitudinal beam to form stable front vertical coupling; the floor longitudinal beam reinforcing piece and the A column lower reinforcing piece are located in an inner cavity of the floor longitudinal beam and an inner cavity of the A column respectively. For a higher safety level, an auxiliary frame front end energy absorption assembly is further added, and the position of the auxiliary anti-collision beam is not ahead of the position of the main anti-collision beam. According to the invention, different collision performance requirements are met by utilizing flexible adjustment of an extremely small part of structure.

Description

Technical Field

[0001] This invention relates to the field of automotive passive safety technology, and in particular to a flexible crashworthy body structure, a subframe front-end energy-absorbing component, and a vehicle configuration method that can be flexibly configured according to different collision safety performance requirements. Background Technology

[0002] In the development of modern automobiles, models under the same platform architecture often need to target different market segments, thus facing different crash safety performance requirements (such as national mandatory standard GB, CNCAP four-star, CNCAP five-star, etc.).

[0003] Existing vehicle body development models typically design drastically different body structure schemes for different safety objectives. For example, to achieve a five-star crash rating, it is usually necessary to comprehensively strengthen core components such as the front longitudinal beams, shotguns (upper longitudinal beams in the front compartment), and floor beams. This traditional "one vehicle, one design" approach results in low commonality of body parts, huge development costs, long design cycles, and extremely high mold investment costs. Furthermore, directly using the body structure of a high-end model (five-star standard) on a low-end model (which only needs to meet national standards) may provide redundant safety performance, but it will cause unnecessary weight increases and material waste, failing to achieve economic efficiency.

[0004] In existing technologies, reinforcement of the front compartment structure often overlooks the coupling effect between the upper and lower longitudinal beams. This can lead to the front and upper longitudinal beams separating independently during offset collisions, failing to generate a combined force. Furthermore, traditional reinforcement methods often involve adding external panels, which may affect the compatibility of surrounding components, resulting in complex design changes.

[0005] Therefore, existing technologies lack a flexible vehicle body structure and solution that can flexibly switch between different collision performances based on the same platform through minimal structural adjustments (especially for front vertical connections and cavity internal reinforcement). Summary of the Invention

[0006] To address the issues of high development costs, long development cycles, and inability to balance economy in existing platform vehicle models when meeting different collision requirements, this invention provides a flexible, crashworthy body structure, a subframe front-end energy-absorbing component, and a vehicle configuration method. This invention achieves a step-by-step improvement in vehicle performance by constructing a vertical force transmission path at the front, implementing concealed internal reinforcement in the floor and A-pillars, and constructing independently assembleable secondary force transmission paths in the chassis.

[0007] To address the aforementioned technical problems, in a first aspect, the present invention provides a flexible, crash-resistant vehicle body structure, comprising:

[0008] A basic vehicle body frame, comprising symmetrically arranged front longitudinal beams, a front compartment upper longitudinal beam located above the front longitudinal beams, an A-pillar connected to the rear of the front compartment upper longitudinal beam, and a floor longitudinal beam extending rearward from the front longitudinal beams; and

[0009] Optionally installable reinforcement components, the reinforcement components being configured to be fitted into a preset area of ​​the base vehicle frame according to a preset collision safety level;

[0010] The enhancement components include at least:

[0011] An upper longitudinal beam connecting reinforcement is disposed between the front section of the front longitudinal beam and the front section of the upper longitudinal beam of the front compartment; one end of the upper longitudinal beam connecting reinforcement is fixedly connected to the upper longitudinal beam of the front compartment, and the other end extends downward and is fixedly connected to the front longitudinal beam, thereby constructing a vertical force transmission path connecting the upper and lower longitudinal beams at the front of the vehicle body; and

[0012] A floor longitudinal beam reinforcement is disposed in the internal cavity of the floor longitudinal beam and extends along the length of the floor longitudinal beam to enhance the deformation resistance of the bottom of the cockpit.

[0013] By connecting the upper and lower longitudinal beams with the upper longitudinal beam reinforcement, the overall torsional stiffness of the front compartment structure is significantly improved, preventing structural separation in offset collisions; by internally reinforcing the floor longitudinal beams, the anti-collapse capability of the passenger compartment floor is improved without changing the external interface of the vehicle floor.

[0014] In a preferred embodiment of the present invention, the upper longitudinal beam connecting reinforcement is constructed as a box-shaped structure, comprising an upper connecting plate, a lower connecting plate, a front connecting plate, and a rear connecting plate welded and fixed to each other. The upper connecting plate is connected to the upper longitudinal beam of the front compartment, and the front and rear connecting plates are connected between the upper and lower connecting plates to form a semi-enclosed reinforcing cavity. The lower connecting plate, front connecting plate, and rear connecting plate are all connected to the front longitudinal beam, forming a semi-enclosed reinforcing cavity. This design, through the welding of four plates to form a three-dimensional box-shaped structure, can better adapt to the spatial curvature between the front and upper longitudinal beams and create a strong clamping effect on the outside of the front longitudinal beam.

[0015] In a preferred embodiment of the present invention, the front end of the floor longitudinal beam reinforcement extends to the rear section of the front longitudinal beam, and the rear end extends to the seat mounting crossbeam area on the floor longitudinal beam; the outer contour of the floor longitudinal beam reinforcement matches the cross-sectional shape of the inner cavity of the floor longitudinal beam. This solution utilizes the redundant space inside the beam to achieve "invisible reinforcement" without requiring changes to the design of the chassis guard plate, piping, and interior carpet.

[0016] As a preferred embodiment of the present invention, the vehicle body structure further includes a lower A-pillar reinforcement member disposed in the internal cavity at the lower end of the A-pillar; the lower A-pillar reinforcement member has an L-shaped plate structure, with its vertical portion attached to the inner wall of the A-pillar and its horizontal portion extending rearward to the door sill beam.

[0017] As a preferred embodiment of the present invention, the basic vehicle body frame further includes a subframe, the front end of which is provided with an installation interface for installing an auxiliary energy-absorbing structure; when the first high-level collision safety rating is met, the front end of the subframe remains uninstalled; when the second high-level collision safety rating, which is higher than the first high-level rating, is met, the front end of the subframe is equipped with a subframe front-end energy-absorbing component.

[0018] To address the aforementioned technical problems, in a second aspect, the present invention provides an energy-absorbing assembly for the front end of a subframe of a vehicle chassis, comprising:

[0019] A pair of bracket extension beams are symmetrically arranged on the left and right sides, and the rear end of the bracket extension beams is configured to be fixedly connected to the front end interface of the subframe;

[0020] A pair of auxiliary energy-absorbing boxes, symmetrically arranged on the left and right, are respectively connected to the front end of the corresponding bracket extension beam; and

[0021] The secondary anti-collision beam is laterally connected between the two secondary energy-absorbing boxes on the left and right sides;

[0022] The bracket extension beam, the secondary energy-absorbing box, and the secondary anti-collision beam together form an auxiliary energy-absorbing and force-transmitting path located below the front longitudinal beam of the vehicle.

[0023] In a preferred embodiment of the present invention, when the subframe front-end energy-absorbing assembly is installed on the vehicle, the front end face of the sub-bumper beam is located in the same vertical plane as the front end face of the main bumper beam, or behind the front end face of the main bumper beam. This positioning design ensures that in a low-speed collision, the main bumper beam contacts the obstacle before the sub-bumper beam, avoiding damage to the expensive subframe system in minor collisions, thus balancing high performance and economical repair.

[0024] As a preferred embodiment of the present invention, it further includes a longitudinal beam connecting beam, the lower end of which is connected to the sub-anti-collision beam, and the upper end extends upward and is configured to connect to the front section of the front longitudinal beam of the vehicle.

[0025] To solve the above-mentioned technical problems, in a third aspect, the present invention provides a vehicle configuration method, comprising:

[0026] S1: Provides a basic vehicle body frame that meets basic safety standards;

[0027] S2: Determine the preset collision safety level of the target vehicle;

[0028] S3: If the preset collision safety level is the highest level, then during the welding process, the upper longitudinal beam connecting reinforcement is welded between the front longitudinal beam and the upper longitudinal beam of the front compartment, and the floor longitudinal beam reinforcement is welded into the inner cavity of the floor longitudinal beam.

[0029] S4: If the preset collision safety level is the second highest level, which is higher than the first highest level, then on the basis of completing S3, the energy-absorbing component at the front end of the subframe is further assembled to the front end of the subframe in the final assembly process.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. High energy absorption efficiency of the front compartment coupling: The upper longitudinal beam connecting reinforcement is used to build a vertical connection at the front, so that the front longitudinal beam and the upper longitudinal beam of the front compartment form a resultant force in the collision, which effectively prevents the upward failure of the Shotgun structure and improves the protection capability of offset collision.

[0032] 2. Concealed upgrade and high versatility: The floor longitudinal beam reinforcement and the A-pillar reinforcement are both installed inside the cavity, so that the external interface and the internal interface of the vehicle body remain unchanged, which greatly simplifies the complexity of multi-model co-production.

[0033] 3. Balancing performance and maintenance costs: The design of the secondary anti-collision beam ensures the energy absorption requirements of three paths in a five-star collision while avoiding damage to the subframe in low-speed collisions, thus reducing maintenance costs for users. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments disclosed in this invention, the accompanying drawings of the embodiments will be briefly described below. These drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0035] Figure 1 This is an exploded view of the upper longitudinal beam connecting reinforcement in an embodiment of the present invention (showing the welding relationship of the four plates).

[0036] Figure 2 This is a schematic diagram of the structure of the upper longitudinal beam connecting reinforcement installed between the front longitudinal beam and the upper longitudinal beam of the front compartment in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the structure of the floor longitudinal beam reinforcement in an embodiment of the present invention (showing the part located inside the cavity).

[0038] Figure 4 This is a bottom view of the floor substructure in an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the structure (L-shaped structure) of the lower reinforcement member of the A-pillar in an embodiment of the present invention.

[0040] Figure 6 This is a structural schematic diagram of the A-pillar inner plate area in an embodiment of the present invention (showing the A-pillar cavity).

[0041] Figure 7 This is a schematic diagram of the structure of the energy-absorbing component at the front end of the subframe in an embodiment of the present invention.

[0042] Figure 8 This is a schematic diagram of the subframe structure in an embodiment of the present invention.

[0043] Figure 9 This is a schematic diagram of the installation structure of the energy-absorbing component at the front end of the subframe in an embodiment of the present invention.

[0044] In the diagram: 10. Front longitudinal beam; 20. Upper longitudinal beam of the front compartment; 21. Upper longitudinal beam connecting reinforcement; 211. Upper connecting plate; 212. Lower connecting plate; 213. Front connecting plate; 214. Rear connecting plate; 30. A-pillar; 31. Lower A-pillar reinforcement; 40. Floor longitudinal beam; 41. Floor longitudinal beam reinforcement; 50. Subframe; 60. Subframe front energy-absorbing assembly; 61. Bracket extension beam; 62. Secondary energy-absorbing box; 63. Secondary anti-collision beam; 64. Longitudinal beam connecting beam. Detailed Implementation

[0045] The technical solutions (including preferred technical solutions) of the present invention will be further described in detail below with reference to the accompanying drawings and by way of listing some optional embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0046] It should be noted that the material parameters involved in this embodiment (such as 340DP, 590DP, etc.) are only examples, and those skilled in the art can make reasonable adjustments according to the weight and strength requirements of the actual vehicle model.

[0047] Example 1

[0048] This embodiment provides a flexible body structure that is enhanced based on a basic body frame, mainly used to meet the CNCAP four-star crash standard.

[0049] like Figure 2 , Figure 9 As shown, the basic vehicle body frame includes a front longitudinal beam 10 arranged symmetrically on the left and right, a front compartment upper longitudinal beam 20 (Shotgun) located above the front longitudinal beam 10, an A-pillar 30 connected to the rear of the front compartment upper longitudinal beam 20, and a floor longitudinal beam 40 that supports the rearward extension of the front longitudinal beam 10.

[0050] To improve the rigidity of the front and bottom of the vehicle body, the following reinforcing components are welded onto the basic frame in this embodiment:

[0051] 1. Upper longitudinal beam connecting reinforcement 21

[0052] like Figure 2 As shown, the upper longitudinal beam connecting reinforcement 21 is located between the front section of the front longitudinal beam 10 and the front section of the upper longitudinal beam 20 in the front compartment. It acts as a "vertical tie rod," "binding" the upper and lower longitudinal beams together at the front of the vehicle.

[0053] Specific structure: such as Figure 1 As shown, the reinforcing member 21 has a three-dimensional semi-enclosed box-shaped structure, which is assembled and welded from four independent stamped plates, specifically including:

[0054] Sidewall configuration: The front connecting plate 213 and the rear connecting plate 214 respectively constitute the front and rear sidewalls (i.e., vertical reinforcing ribs) of the box-shaped structure. In some embodiments of the present invention, the front connecting plate 213 and the rear connecting plate 214 can form a hollow column with open ends, or form three sidewalls of a hollow column with open ends.

[0055] Top sealing plate: The upper connecting plate 211 is welded and fixed to the top of the front connecting plate 213 and the rear connecting plate 214.

[0056] Bottom sealing plate: The lower connecting plate 212 is welded and fixed to the bottom of the front connecting plate 213 and the rear connecting plate 214.

[0057] Connection relationships: Upper connection: The upper connecting plate 211 is welded to the upper longitudinal beam 20 (Shotgun) of the front compartment. Lower connection: This component is fixed to the front longitudinal beam 10 by multi-face welding. Specifically, the front connecting plate 213, the rear connecting plate 214, and the lower connecting plate 212 are all directly connected to the outer side wall of the front longitudinal beam 10 (usually by welding).

[0058] This construction method utilizes the front and rear connecting plates as strong vertical supports, combined with the sealing effect of the lower connecting plate, to create a large welding area and shear strength at the connection with the front longitudinal beam. This "three-plate locking" connection structure ensures that even if the front longitudinal beam undergoes severe deformation during a collision, the reinforcement 21 will not easily fall off, thus continuously playing the role of a "vertical tie rod" to pull the upper longitudinal beam 20 of the upper front compartment to absorb energy.

[0059] Principle of mechanical transmission: In a frontal offset collision (such as a 25% small offset collision), the impact force is often concentrated on the outer side of the front longitudinal beam 10. At this time, the upper longitudinal beam connecting reinforcement 21, with its box-shaped rigid structure, quickly diverts the impact force received by the front longitudinal beam 10 upwards to the upper longitudinal beam 20 in the front compartment. This linkage mechanism effectively prevents the upper longitudinal beam 20 in the front compartment from buckling upwards due to lack of lower support, and also provides lateral support for the front longitudinal beam 10, preventing it from bending prematurely.

[0060] 2. Floor longitudinal beam reinforcement component 41 (internal cavity reinforcement)

[0061] Please see Figure 3 and Figure 4 The floor longitudinal beam reinforcement 41 is located in the internal cavity of the floor longitudinal beam 40.

[0062] Installation location: It is located in the internal cavity of the floor longitudinal beam 40. Its front end extends into the rear section of the front longitudinal beam 10 (i.e., the corner below the front bulkhead), and its rear end extends rearward to the seat mounting beam area.

[0063] Structural features: The outer contour of the floor longitudinal beam reinforcement 41 is designed to match the cross-sectional shape of the inner cavity of the floor longitudinal beam 40 (e.g., a slightly smaller U-shaped groove).

[0064] This "in-cavity beam" design, compared to traditional external panels, does not alter the external dimensions of the floor longitudinal beam 40, thus eliminating the need to redesign the chassis skid plate, exhaust pipe hanger positions, and interior carpet shape. This allows vehicles with different safety levels to fully share chassis and interior parts.

[0065] 3. A-pillar under-pillar reinforcement 31 (internal cavity reinforcement)

[0066] Please see Figure 5 and Figure 6 The lower reinforcement 31 of the A-pillar is located in the internal cavity of the A-pillar 30.

[0067] Structural form: It is an L-shaped plate structure that is installed in the internal cavity at the lower end of the A-pillar 30.

[0068] Connection relationship: Its vertical part is welded to the inner wall of A-pillar 30, and the horizontal part extends backward into the connection node between the sill beam and A-pillar.

[0069] This enhances the deformation resistance of the cockpit door frame opening and prevents wheels from intruding into the cockpit.

[0070] Example 2

[0071] Based on Example 1, this embodiment further provides a chassis enhancement scheme for achieving the CNCAP five-star crash test standard.

[0072] like Figure 7 , Figure 8 and Figure 9 As shown, in order to meet the more stringent collision energy management requirements of the five-star standard, simply reinforcing the upper part of the vehicle body is no longer sufficient; it is necessary to develop a chassis sub-force transmission path. In this embodiment, a subframe 50 is used as a base to construct a subframe front-end energy-absorbing component 60.

[0073] like Figure 8 As shown, the front end of the basic subframe 50 has reserved bolt connection holes or welding surfaces.

[0074] like Figure 7 and Figure 9 As shown, the subframe front-end energy-absorbing assembly 60 includes:

[0075] Bracket extension beam 61: Its rear end is fixedly connected to the front end of the subframe 50 and extends forward. It serves to extend the force transmission path of the subframe forward.

[0076] Secondary energy-absorbing box 62: Connected to the foremost end of the bracket extension beam 61. It is designed with a crumple guide groove, which can undergo controlled deformation in the early stages of low-speed or high-speed collisions to absorb energy.

[0077] Sub-bumper beam 63: Spanning across and connecting the two sub-energy-absorbing boxes 62 on the left and right sides. It not only increases the lateral stiffness of the front end, but also helps to capture obstacles in small offset collisions, preventing them from directly impacting the suspension by avoiding the longitudinal beams.

[0078] Longitudinal beam connecting beam 64: such as Figure 7 As shown, the component also includes an upwardly extending connecting arm for connecting the secondary anti-collision beam system to the front longitudinal beam 10 of the main body (or the energy-absorbing box area of ​​the front anti-collision beam). This forms a closed "U"-shaped front end frame, greatly improving the overall structural stability of the front of the vehicle.

[0079] like Figure 9 As shown, the front end face of the secondary anti-collision beam 63 is designed not to be ahead of (i.e. located on the same vertical plane or behind) the front end face of the vehicle's main anti-collision beam.

[0080] By adding this component (total weight increase of approximately 14KG including the content of Example 1), the vehicle has three main force transmission paths: the upper Shotgun path, the middle front longitudinal beam path, and the lower subframe path, thereby meeting the five-star collision energy absorption requirements.

[0081] In low-speed collisions (such as at 15 km / h), the main anti-collision beam contacts the obstacle first, protecting the energy-absorbing components of the subframe; in high-speed collisions, as the main beam collapses, the secondary anti-collision beam intervenes in time to provide a lower energy-absorbing path.

[0082] In some embodiments of the present invention, the upper longitudinal beam connecting reinforcement 21 adopts a four-plate welded structure and is disposed between the front section of the front longitudinal beam and the upper longitudinal beam of the front compartment. Its front, rear, and lower connecting plates are all welded to the front longitudinal beam to form a stable front vertical coupling. The floor longitudinal beam reinforcement and the lower A-pillar reinforcement are located in the internal cavities of the floor longitudinal beam and the A-pillar, respectively. For higher safety levels, a subframe front-end energy-absorbing component is further added, and its secondary anti-collision beam position does not exceed that of the main anti-collision beam. The present invention achieves flexible adjustment of a very small part of the structure to meet different collision performance requirements.

[0083] Example 3

[0084] The present invention also relates to a vehicle configuration method based on the above structure.

[0085] Step S1: During the platform planning phase, design a unified basic body-in-white and reserve installation points (such as weld points and bolt holes) for the aforementioned reinforcement components.

[0086] In other words, in the welding workshop of the automobile factory, all models based on this platform are produced on the same main production line, resulting in a standardized basic body structure that meets the first collision safety level (GB national standard). At this stage, all mounting interfaces (positioning holes, welding surfaces, etc.) used for subsequent upgrades are integrated into the body stamping and welding processes as standard procedures.

[0087] Step S2: Each vehicle body entering the welding line has a unique identification code (such as the prefix code of the VIN), which is associated with the production order in the MES system. Based on the order information (such as "five-star safety package configuration"), the MES system automatically identifies the target collision safety level that the current vehicle body needs to achieve.

[0088] If the target is the highest level of crash safety (e.g., according to the GB national standard), the basic body can be used directly without installing additional reinforcement packages, achieving low cost and low fuel consumption.

[0089] If the target is the highest level of collision safety (e.g., CNCAP four stars), the MES system will issue instructions to the material delivery system (such as AGVs) to deliver the reinforcement component package, which includes the upper longitudinal beam connection reinforcement 21, the A-pillar lower reinforcement 31, and the floor longitudinal beam reinforcement 41, to the designated robot workstation on time.

[0090] If the target is the second highest level of crash safety rating (e.g., CNCAP five stars), MES will instruct the delivery of a complete package including reinforcement components and energy-absorbing components for the front end of the subframe.

[0091] Step S3: When the vehicle moves to the designated workstation, the sensor reads the vehicle identification code, and the workstation's control system (PLC) receives the work instruction from the MES.

[0092] Step S4: When the production target is a CNCAP four-star model, an additional process is added in the welding workshop to weld the upper longitudinal beam connecting reinforcement 21, the floor longitudinal beam reinforcement 41 and the A-pillar lower reinforcement 31 to the body-in-white.

[0093] Step S5: When the production target is a CNCAP five-star model, in addition to performing step S4, the energy-absorbing component 60 at the front end of the subframe is also assembled onto the chassis subframe in the final assembly workshop.

[0094] After installation, online visual inspection systems or ultrasonic flaw detectors may be used to quickly and non-destructively inspect the quality of critical weld points, ensuring the reliability of the installation. The entire process requires no manual intervention, achieving highly efficient and high-quality flexible production.

[0095] This strategy enables a single platform to cover all performance boundaries, achieving a precise match between cost and performance.

[0096] It will be readily understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, substitutions, improvements, etc., made under the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A flexible, crash-resistant vehicle body structure, characterized in that, include: The basic body frame includes a front longitudinal beam symmetrically arranged on the left and right, a front compartment upper longitudinal beam located above the front longitudinal beam, an A-pillar connected to the rear of the front compartment upper longitudinal beam, and a floor longitudinal beam that supports the rearward extension of the front longitudinal beam. as well as Optionally installable reinforcement components, the reinforcement components being configured to be fitted into a preset area of ​​the base vehicle frame according to a preset collision safety level; The enhancement components include at least: An upper longitudinal beam connecting reinforcement is disposed between the front section of the front longitudinal beam and the front section of the upper longitudinal beam of the front compartment; one end of the upper longitudinal beam connecting reinforcement is fixedly connected to the upper longitudinal beam of the front compartment, and the other end extends downward and is fixedly connected to the front longitudinal beam, thereby constructing a vertical force transmission path connecting the upper and lower longitudinal beams at the front of the vehicle body; and A floor longitudinal beam reinforcement is disposed in the internal cavity of the floor longitudinal beam and extends along the length of the floor longitudinal beam to enhance the deformation resistance of the bottom of the cockpit.

2. The flexible crash-resistant vehicle body structure according to claim 1, characterized in that, The upper longitudinal beam connecting reinforcement is a semi-enclosed box structure, which includes an upper connecting plate, a lower connecting plate, a front connecting plate and a rear connecting plate that are welded and fixed to each other. The front connecting plate and the rear connecting plate are connected to form the sidewall of the semi-enclosed box structure; the upper connecting plate is connected to the top of the front connecting plate and the rear connecting plate, and the lower connecting plate is welded to the bottom of the front connecting plate and the rear connecting plate. The upper connecting plate is connected to the upper longitudinal beam of the front compartment, and the front connecting plate, the rear connecting plate and the lower connecting plate are all connected to the front longitudinal beam.

3. The flexible crash-resistant vehicle body structure according to claim 1, characterized in that, The front end of the floor longitudinal beam reinforcement extends to the rear section of the front longitudinal beam, and the rear end extends to the seat mounting beam area on the floor longitudinal beam; the outer contour of the floor longitudinal beam reinforcement matches the cross-sectional shape of the inner cavity of the floor longitudinal beam.

4. The flexible crash-resistant vehicle body structure according to claim 1, characterized in that, The vehicle body structure also includes a lower A-pillar reinforcement member, which is disposed in the internal cavity at the lower end of the A-pillar; The A-pillar reinforcement has an L-shaped plate structure, with its vertical part attached to the inner wall of the A-pillar and its horizontal part extending backward to the door sill beam.

5. The flexible crashworthy vehicle body structure according to any one of claims 1 to 4, characterized in that, The basic vehicle body frame also includes a subframe, the front end of which is reserved with an installation interface for installing an auxiliary energy-absorbing structure; When the highest level of collision safety is met, the front end of the subframe remains uninstalled. When the collision safety level meets the second highest level, which is higher than the first highest level, a subframe front energy-absorbing assembly is installed at the front end of the subframe.

6. A subframe front-end energy-absorbing assembly for a vehicle chassis, suitable for the body structure as described in any one of claims 1-5, characterized in that, include: A pair of bracket extension beams are symmetrically arranged on the left and right sides, and the rear end of the bracket extension beams is configured to be fixedly connected to the front end interface of the subframe; A pair of auxiliary energy-absorbing boxes, symmetrically arranged on the left and right, are respectively connected to the front end of the corresponding bracket extension beam; as well as The secondary anti-collision beam is laterally connected between the two secondary energy-absorbing boxes on the left and right sides; The bracket extension beam, the secondary energy-absorbing box, and the secondary anti-collision beam together form an auxiliary energy-absorbing and force-transmitting path located below the front longitudinal beam of the vehicle.

7. The subframe front-end energy-absorbing assembly according to claim 6, characterized in that, When the subframe front energy-absorbing assembly is installed on the vehicle, the front end face of the sub-bumper beam is located in the same vertical plane as the front end face of the main bumper beam, or behind the front end face of the main bumper beam, to ensure that the main bumper beam contacts the obstacle before or simultaneously with the sub-bumper beam when a collision occurs.

8. The subframe front-end energy-absorbing assembly according to claim 6, characterized in that, It also includes a longitudinal beam connecting beam, the lower end of which is connected to the sub-bumper beam, and the upper end extends upward and is configured to connect to the front section of the vehicle's front longitudinal beam, thereby forming a vertical support between the subframe plane and the front longitudinal beam plane.

9. A vehicle configuration method based on the vehicle body structure of claim 1, characterized in that, Includes the following steps: S1: Provide a basic vehicle body frame that meets basic safety standards; S2: Determine the preset collision safety level of the target vehicle; S3: If the preset collision safety level is the highest level, then during the welding process, the upper longitudinal beam connecting reinforcement is welded between the front longitudinal beam and the upper longitudinal beam of the front compartment, and the floor longitudinal beam reinforcement is welded into the inner cavity of the floor longitudinal beam. S4: If the preset collision safety level is a second higher level than the first higher level, then on the basis of completing S3, the energy-absorbing component at the front end of the subframe as described in any one of claims 5 to 8 is further assembled to the front end of the subframe in the final assembly process.

10. The method according to claim 9, characterized in that, In step S3, the upper longitudinal beam connecting reinforcement is assembled and welded from four independent connecting plates; the lower A-pillar reinforcement is pre-welded and fixed to the inner side of the inner A-pillar before the inner and outer A-pillar plates are fastened and welded together.

11. The method according to claim 9, characterized in that, The first high level corresponds to the CNCAP four-star standard, and the second high level corresponds to the CNCAP five-star standard; in step S4, the energy-absorbing component at the front end of the subframe is fixed to the subframe as a pre-assembled modular assembly by bolt connection.

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