Connecting piece, connecting method, vehicle lower body structure and vehicle wheelbase adjustment method

Abstract

This invention discloses a connector, a connection method, a vehicle underbody structure, and a vehicle wheelbase adjustment method. The connector includes a base plate and a connecting structure disposed on the surface of the base plate. The base plate is a centrally symmetrical structure used for fixed connection with a first component. The connecting structure is used for fixed connection with a second component. If the connecting structure is rotated 180° around a first axis, the position of the connecting structure after rotation can be translated along a first direction to coincide with its position before rotation. The first axis passes through the center of symmetry of the base plate and is perpendicular to the surface of the base plate, while the first direction is parallel to the surface of the base plate. By rotating the connector around the first axis, the position of the base plate remains unchanged before and after rotation, while the connecting structure only undergoes a translational change in position before and after rotation, with everything else remaining unchanged. This allows for two different overall structures after the final connection, provided that the structures of the first component, the second component, and the adapter remain unchanged.

Description

Technical Field

[0001] This invention relates to the field of installation and connection technology, specifically to a connector, a connection method, a vehicle underbody structure, and a vehicle wheelbase adjustment method. Background Technology

[0002] The main function of a connector is to achieve the connection and transition between two components. When the structures of the two connected components remain unchanged, there is usually only one connection method. That is, the final overall structure formed after the connection is unique. It cannot be used in application scenarios where two components are connected by the same connector and the relative positions of the two components can be adjusted in a certain direction. Summary of the Invention

[0003] The problem to be solved by the present invention is to provide a connector, a connection method, a vehicle underbody structure and a vehicle wheelbase adjustment method. When the connector connects two components, it can form two final integrated structures by rotating itself.

[0004] To address the aforementioned technical problems, the present invention provides a connector, comprising a base plate and a connecting structure disposed on the surface of the base plate; the base plate is a centrally symmetrical structure for fixed connection with a first component; the connecting structure is for fixed connection with a second component.

[0005] If the connecting structure is rotated 180° around the first axis, the position of the connecting structure after rotation can be translated along the first direction to coincide with the position before rotation; the first axis passes through the center of symmetry of the base plate and is perpendicular to the surface of the base plate, and the first direction is parallel to the surface of the base plate;

[0006] When the first component and the second component are connected using the connector, two connection states can be formed. The relative positions of the first component and the second component in the first direction are different in these two connection states. Moreover, the first component and the second component in these two connection states are only different in relative position in the first direction, and are otherwise the same.

[0007] In the aforementioned connector, rotating the connector around the first axis ensures that the base plate, being a centrally symmetrical structure, remains in the same position before and after rotation, meaning the connection with the first component remains unchanged. The connecting structure, however, can overlap with the base plate by translating along the first direction before and after rotation. Therefore, the connection with the second component only undergoes a translational change in position, while other aspects remain constant. This allows for two connection states between the first and second components when the connector is used to connect them. Rotating the connector 108° around the first axis maintains the fixed position and state of the base plate on the first component while allowing the second component to translate a certain distance relative to the first component in the first direction. This enables two different connection states where the relative positions of the two components in the first direction differ.

[0008] With the structures of the first component, the second component, and the adapter remaining unchanged, the final connection has two integrated structures, suitable for connection situations where the relative positions of the first component and the second component need to be adjustable in the first direction.

[0009] It should be noted that the connection between the connector and the first and second components will not be affected by the rotation of the connector. That is, compared with before the rotation, the second component needs to be translated before connecting with the connector, and there will be no interference or other issues affecting the connection.

[0010] As an improvement to the connector of the present invention, the connection structure includes a plurality of connection units, which are evenly spaced and arranged on one side of the center of symmetry of the base plate.

[0011] The connection structure is formed by connecting units arranged at uniform intervals. Each connecting unit has the same structure, which makes it easy to achieve the positional state before and after rotation around the first axis by translation and overlap.

[0012] Furthermore, the arrangement direction of the plurality of connecting units is perpendicular to the first direction. Preferably, the center of symmetry of the base plate is located on the plane of symmetry of the arrangement of the connecting units.

[0013] Furthermore, the connecting unit includes a boss on one side of the base plate, and the top surface of the boss has a mounting hole for fixed connection with the second component.

[0014] Preferably, the mounting hole is a threaded hole with its axis perpendicular to the surface of the base plate; the boss has a cylindrical structure and is coaxial with the mounting hole.

[0015] Preferably, a rib is provided between the side of each boss and the surface of the base plate to increase structural strength.

[0016] As another improvement to the connector of the present invention, the base plate is connected to the first component by welding or riveting. Preferably, the welding point or riveting point is symmetrical about the center of symmetry of the base plate.

[0017] To address the aforementioned technical problems, another aspect of the present invention provides a connection method based on the aforementioned connector, comprising:

[0018] The target connection posture of the connector is determined based on the target relative position relationship between the first component and the second component in the first direction;

[0019] According to the target connection posture of the connector, the connector is fixedly connected to the first component through the base plate;

[0020] According to the target connection posture of the connector, the connector is fixedly connected to the second component through the connection structure;

[0021] There are two connection postures for the connectors, and the connection structures of these two postures are located on both sides of the center of symmetry of the base plate in the first direction.

[0022] In the above connection method, based on the relative position requirements of the first component and the second component in the first direction when connecting, one of two connection postures is selected as the target connection posture for connection.

[0023] To address the aforementioned technical problems, the present invention also provides a vehicle underbody structure, including a left longitudinal beam, a right longitudinal beam, a CTC battery pack assembly, and a rear floor assembly; the CTC battery pack assembly includes battery cells and a front floor, with its two sides fixedly connected to the left and right longitudinal beams respectively; the front ends of the rear floor assembly are fixedly connected to the left and right longitudinal beams respectively, and the fixed connection positions are adjustable along the longitudinal direction of the vehicle body; the front center of the rear floor assembly is fixedly connected to the rear end of the CTC battery pack assembly via the aforementioned connector; the first direction is along the longitudinal direction of the vehicle body.

[0024] Preferably, the CTC battery pack assembly uses CTC technology to integrate the front floor and seat crossbeams onto the upper cover of the battery pack; the battery pack uses square battery modules.

[0025] CTC (Cell to Chassis) battery integration technology, which eliminates the need for a battery pack and directly integrates the cells into the lower body of the vehicle, represents a structural innovation that integrates the battery and body architecture at a physical level. This eliminates redundancy and creates more space for cell placement, effectively increasing vehicle range. However, currently, there are no vehicle structures on the market that utilize integrated CTC battery packs to extend the wheelbase without altering the integrated body components. Therefore, different wheelbase models require customized body structures and CTC battery packs, necessitating the development of new molds and incurring significant costs.

[0026] In the aforementioned vehicle underbody structure, the rear floor assembly and the CTC battery pack assembly are connected via a connector. During installation, rotating and adjusting the connector allows for two connection states. Since the first direction is along the vehicle's longitudinal direction, the total longitudinal length of the two connection states differs. Therefore, during installation, when adjusting the rear floor assembly's longitudinal position relative to the left and right longitudinal beams, rotating and adjusting the connector can compensate for the installation gap between the rear floor assembly and the CTC battery pack assembly caused by the rear floor assembly's position adjustment. This maintains the structural integrity of the CTC battery pack assembly, rear floor assembly, and connector, eliminating the need to develop new products or molds, and enabling wheelbase adjustment, thus saving costs.

[0027] As an improvement to the vehicle underbody structure of the present invention, the position of the connector fixed on the rear floor assembly can be adjusted longitudinally along the vehicle body. That is, the position of the connector on the rear floor assembly can be adjusted within a certain range in both the forward and reverse states.

[0028] During installation, when adjusting the installation position of the rear floor assembly relative to the left and right longitudinal beams along the vehicle's longitudinal direction, the connecting parts are rotated and adjusted. This, along with the position of the base plate fixed on the rear floor assembly, is adjusted along the vehicle's longitudinal direction. Within a certain size range, this can compensate for the installation gap between the rear floor assembly and the CTC battery pack assembly caused by the adjustment of the rear floor assembly's position. This results in a wider range of adjustable wheelbase for the vehicle, making the actual wheelbase adjustable design more flexible.

[0029] Preferably, the rear floor assembly includes a rear floor body, and a connecting plate is provided at the front end of the rear floor body; one side surface of the connecting plate is horizontal, and this horizontal surface is used to be fixedly connected to the surface of the base plate, and the position of the base plate fixed on the horizontal surface can be adjusted along the longitudinal direction of the vehicle body. Preferably, the bottom surface of the connecting plate is fixedly connected to the base plate.

[0030] The base plate is attached and fixed to the horizontal surface of the connecting plate, making the connection easy and the position convenient to adjust along the longitudinal direction of the vehicle body. It should be noted that adjusting the position of the base plate on the connecting plate along the longitudinal direction of the vehicle body does not affect the connection between the connector and the CTC battery pack assembly.

[0031] As another improvement to the vehicle underbody structure of the present invention, a first bolt hole group is provided at the end of the left longitudinal beam. The first bolt hole group includes a plurality of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The first bolt hole group is used to fix and connect to the front end side of the rear floor assembly, and the number of bolt holes in the first bolt hole group is greater than the number of bolt holes corresponding to the rear floor assembly.

[0032] During installation, by changing the specific fastening bolt holes used when connecting the rear floor assembly to the first bolt hole group, the fixed connection position between the rear floor assembly and the left longitudinal beam can be adjusted along the longitudinal direction of the vehicle body.

[0033] Furthermore, a second bolt hole group is provided at the end of the right longitudinal beam. The second bolt hole group includes a plurality of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The second bolt hole group is used for fixed connection with the front end of the rear floor assembly, and the number of bolt holes in the second bolt hole group is greater than the number of bolt holes corresponding to the rear floor assembly. The structure of the right longitudinal beam is symmetrical to the structure of the left longitudinal beam.

[0034] Furthermore, a left connecting beam and a right connecting beam are respectively provided on both sides of the front end of the rear floor body. The left connecting beam is used to fix the end of the left longitudinal beam; the right connecting beam is used to fix the end of the right longitudinal beam.

[0035] Preferably, the left connecting beam, the right connecting beam, and the connecting plate are arranged in a U-shape. The main body of the left connecting beam is fixedly connected to the inner side of the left longitudinal beam; the main body of the right connecting beam is fixedly connected to the inner side of the right longitudinal beam.

[0036] As another improvement to the vehicle underbody structure of the present invention, the fixed connection position of the CTC battery pack assembly on the left longitudinal beam and the right longitudinal beam can be adjusted along the longitudinal direction of the vehicle body.

[0037] By rotating and adjusting the connecting parts, the position of the base plate fixed on the horizontal surface of the connecting plate is adjusted longitudinally along the vehicle body. In addition, the fixed position of the CTC battery pack assembly on the left and right longitudinal beams is adjusted longitudinally along the vehicle body, so that the rear floor assembly has a larger adjustment range relative to the left and right longitudinal beams, thereby further widening the vehicle wheelbase adjustment range.

[0038] Furthermore, the vehicle's lower body structure also includes an engine compartment assembly, the rear ends of which are fixedly connected to the left longitudinal beam and the right longitudinal beam, respectively; the rear center of the engine compartment assembly is fixedly connected to the front end of the CTC battery pack assembly via the connectors described above.

[0039] Preferably, the position of the connector fixed to the cabin assembly is adjustable along the longitudinal direction of the vehicle body.

[0040] The CTC battery pack assembly is connected to the engine compartment assembly at the front end via a connector. This compensates for the gap caused by the adjustment of the CTC battery pack assembly relative to the longitudinal beam. Together with the connector at the rear end, this further enables the vehicle to have a wider range of adjustable wheelbase.

[0041] Preferably, the fixed connection positions of the rear ends of the engine compartment assembly to the left and right longitudinal beams, respectively, are not adjustable. Since the engine compartment assembly involves the installation of numerous components such as the cockpit, it is preferable to design it so that its position relative to the longitudinal beams is non-adjustable.

[0042] Furthermore, a third bolt hole group is provided in the middle of the left longitudinal beam. The third bolt hole group includes a number of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The third bolt hole group is used to fix and connect to one side of the CTC battery pack assembly, and the number of bolt holes in the third bolt hole group is greater than the number of bolt holes corresponding to the CTC battery pack assembly.

[0043] During installation, by changing the specific fastening bolt holes used when connecting the CTC battery pack assembly to the left longitudinal beam, the fixed connection position between the CTC battery pack assembly and the left longitudinal beam can be adjusted along the longitudinal direction of the vehicle body.

[0044] Preferably, a fourth bolt hole group is provided in the middle of the right longitudinal beam. The fourth bolt hole group includes a number of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The fourth bolt hole group is used to fix and connect to one side of the CTC battery pack assembly, and the number of bolt holes in the fourth bolt hole group is greater than the number of bolt holes corresponding to the CTC battery pack assembly.

[0045] As a further improvement to the vehicle underbody structure of the present invention, both sides of the floor plate are along the longitudinal direction of the vehicle body, and a first reinforcing plate is provided on each side; the surface of the first reinforcing plate is perpendicular to the floor plate and is used to fix it to the rear floor assembly; a second reinforcing plate is also provided on the floor plate, the surface of the second reinforcing plate is perpendicular to the floor plate, and both ends are fixed to a first reinforcing plate; a rib is provided between the second reinforcing plate and the floor plate.

[0046] The first and second reinforcing plates increase the structural strength of the entire connector and the reliability of its connection with the rear floor assembly.

[0047] Preferably, the rear floor assembly is provided with a mounting surface that is fitted and fixedly connected to the first reinforcing plate.

[0048] As another improvement to the vehicle underbody structure of the present invention, the engine compartment assembly, left longitudinal beam, right longitudinal beam, rear floor assembly, and connecting parts are all integrally die-cast.

[0049] Traditional car body manufacturing involves stamping individual parts first, then welding them into a complete body assembly. A single vehicle is typically constructed from over 500 parts of varying shapes and materials. Before mass production, the entire vehicle undergoes three rounds of matching and debugging over six months, rigorously checking and solidifying the manufacturing status, materials, tooling, processes, product qualification rates, packaging, and transportation of these 500+ parts to ensure the final body quality meets assembly requirements. Recently, unibody die casting technology has emerged as a new trend in car body manufacturing. Unibody die casting involves a single molding process, eliminating the complex stamping and welding steps. This simplifies the manufacturing process, requiring only one part and eliminating the need for extensive tooling and the accumulation of errors from connecting numerous parts. Manufacturing precision is controllable. The elimination of the need to inspect the manufacturing status of each individual part not only shortens the complex car body manufacturing process but also significantly reduces manufacturing costs.

[0050] Preferably, the connector and the rear floor assembly are made of aluminum and are fixedly connected by riveting.

[0051] To address the aforementioned technical problems, the present invention further provides a method for adjusting the wheelbase of a vehicle based on the aforementioned vehicle underbody structure, comprising: adjusting the position of the front end of the rear floor assembly, which is fixedly connected to the left longitudinal beam and the right longitudinal beam, along the longitudinal direction of the vehicle body, and eliminating the gap between the front end of the rear floor assembly and the rear end of the CTC battery pack assembly caused by the position adjustment using a first method; wherein, the first method includes rotating a connector fixed to the rear floor assembly by 180° around a first axis. This refers to the connector rotating by 180° around its own first axis.

[0052] Furthermore, the first method also includes: adjusting the connection fixed to the rear floor assembly along the longitudinal direction of the vehicle body; adjusting the fixed connection position of the CTC battery pack assembly on the left longitudinal beam and the right longitudinal beam along the longitudinal direction of the vehicle body; rotating the connection fixed to the engine compartment assembly by 180° around a first axis; and adjusting the connection fixed to the engine compartment assembly along the longitudinal direction of the vehicle body.

[0053] The beneficial effects of this invention are that, when the first component and the second component are connected using the aforementioned connector, rotating the connector 108° around the first axis allows the second component to be translated a certain distance relative to the first component in the first direction while maintaining the fixed position and state of the base plate on the first component. This enables two connection states between the first and second components, allowing adjustment of their relative positions in the first direction. The aforementioned vehicle underbody structure and wheelbase adjustment method possess the advantages of the aforementioned connection structure and can adjust the vehicle wheelbase without altering the components of the vehicle underbody structure. Attached Figure Description

[0054] In the attached diagram:

[0055] Figure 1 This is a structural diagram of the connector of the present invention.

[0056] Figure 2 For the connector of the present invention from Figure 1 A structural diagram showing the state rotated 180° around the first axis.

[0057] Figure 3 This is a bottom structural diagram of the connector of the present invention.

[0058] Figure 4 This is a structural diagram of the vehicle's lower body structure according to the present invention.

[0059] Figure 5 This is a split structural diagram of the vehicle's lower body structure according to the present invention.

[0060] Figure 6 This is a structural diagram of the rear floor assembly of the vehicle's lower body structure according to the present invention.

[0061] Figure 7 This is a structural diagram showing the connection of the vehicle's lower body structure of the present invention installed at the bottom of the rear floor assembly.

[0062] Figure 8 for Figure 7 A breakdown diagram.

[0063] Figure 9 for Figure 7 The structural diagram of the connector after rotating 180° around the first axis.

[0064] Figure 10 This is a structural diagram of the left longitudinal beam of the vehicle's lower body structure according to the present invention.

[0065] Figure 11 This is a structural diagram of the bottom of the left longitudinal beam of the vehicle's lower body structure according to the present invention.

[0066] Figure 12 This is a structural diagram of the CTC battery pack assembly in the vehicle's underbody structure according to the present invention.

[0067] Figure 13 This is a schematic diagram showing the connections of the various components in the vehicle wheelbase adjustment method of the present invention.

[0068] Figure 14 This is a schematic diagram of the first connection state of the two components of the connection method of the present invention.

[0069] Figure 15 This is a schematic diagram of the second connection state of the two components of the connection method of the present invention.

[0070] In the diagram, 1. Left longitudinal beam; 11. First bolt hole group; 12. Third bolt hole group; 13. Fifth bolt hole group; 101. Outer rectangular beam; 102. Inner rectangular beam; 2. Right longitudinal beam; 3. CTC battery pack assembly; 31. Fixed connecting lug; 4. Rear floor assembly; 41. Rear floor body; 42. Left connecting beam; 43. Right connecting beam; 44. Connecting plate; 5. Cabin assembly; 6. Connector; 61. Base plate; 62. Boss; 621. Mounting hole; 63. First reinforcing plate; 64. Second reinforcing plate; 651. Connecting rib; 652. Combined rib; 66. Connecting structure; 71. First shaft; 72. First direction; 73. First component; 73. Second component. Detailed Implementation

[0071] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions of the embodiments are for the purpose of helping to understand the present invention, but do not constitute a limitation thereof.

[0072] Example 1

[0073] Figure 1-3A connector 6 according to the present invention is shown. For example... Figure 1-3 As shown, the connector 6 includes a base plate 61 and a connecting structure disposed on the surface of the base plate 61; the base plate 61 is a centrally symmetrical structure used for fixed connection with the first component; the connecting structure is used for fixed connection with the second component. If the connecting structure is rotated 180° around the first axis 71, the position state of the connecting structure after rotation can be translated along the first direction 72 to coincide with the position state before rotation; the first axis 71 passes through the center of symmetry of the base plate 61 and is perpendicular to the surface of the base plate 61, and the first direction 72 is parallel to the surface of the base plate 61.

[0074] In use, the first and second components have two connection states, corresponding to the connectors 6 as follows: Figure 1 and Figure 2 The two states shown have the same structure at the connection between the first component and the base plate 61, and the same structure at the connection between the second component and the connecting structure. The only difference is the relative position of the first component and the second component in the first direction. Figure 7 and Figure 9 As shown in .

[0075] In some embodiments, the connection structure includes a plurality of connection units, which are evenly spaced and arranged on one side of the center of symmetry of the base plate 61. The arrangement direction of the connection units is perpendicular to the first direction 72. The center of symmetry of the base plate 61 is located on the plane of symmetry of the connection units. The connection structure is formed by the evenly spaced connection units, and each connection unit has the same structure, which makes it easy to achieve the coincidence of the position state before and after rotation around the first axis 71 through translation.

[0076] In some embodiments, the connecting unit includes a boss 62 on one side of the base plate 61, and the top surface of the boss 62 has a mounting hole 621 for fixed connection with the second component.

[0077] Optionally, the mounting hole 621 is a threaded hole with its axis perpendicular to the surface of the base plate 61; the boss 62 has a cylindrical structure and is coaxial with the mounting hole 621.

[0078] Optionally, ribs are provided between the side of each boss 62 and the surface of the base plate 61 to increase structural strength.

[0079] In some embodiments, the base plate 61 is connected to the first component by welding or riveting, which is a simple connection structure and has little impact on the fixed connection between the second component and the connection structure after the second component is moved.

[0080] Optionally, the welding point or riveting point between the base plate 61 and the first component is symmetrical about the center of symmetry of the base plate 61. In this way, the position of the welding point or riveting point is fixed before and after rotation, that is, the connection operation between the base plate 61 and the first component remains unchanged before and after the connection member 6 rotates.

[0081] Example 2

[0082] The present invention provides a connection method based on the aforementioned connector 6, comprising the following steps S10-S30. For example... Figure 1 and Figure 2 The connector 6 has two connection postures. The connection structures 66 of these two connection postures are located on both sides of the center of symmetry of the base plate 61 in the first direction, respectively forming... Figure 14 and Figure 15 The two connection states shown represent two relative positional relationships between the first component 73 and the second component 74 in the first direction. Figure 14 and Figure 15 The first component 73, the second component 74, and the connector 6 are abstracted, mainly expressing their relative positions and connection relationships in the first direction. The dashed line indicates a fixed connection.

[0083] Step S10: Determine the target connection posture of connector 6 based on the target relative position relationship between the first component 73 and the second component 74 in the first direction. There are two possible target relative position relationships between the first component 73 and the second component 74 in the first direction: one is a distance d1, such as... Figure 14 As shown, the connecting structure 66 of the corresponding connector 6 is located on the right side of the center of the support of the base plate 61; another type is separated by d2, as shown... Figure 15 As shown, the connecting structure 66 of the corresponding connector 6 is located on the left side of the center of the support of the base plate 61.

[0084] Step S20: According to the target connection posture of the connector 6, the connector 6 is fixedly connected to the first component 73 through the base plate 61.

[0085] Step S30: According to the target connection posture of the connector 6, the connector 6 is fixedly connected to the second component 74 through the connection structure 66.

[0086] During connection, based on the relative positional relationship requirements of the first component 73 and the second component 74 in the first direction, i.e. the target relative positional relationship, the connection posture of the connector is determined as one of the two connection postures. Then the connection is performed. Note that in both connection states, the connection position and method between the base plate 61 of the adapter 6 and the first component 73 remain unchanged. Similarly, the connection position and method between the connection structure 66 of the adapter 6 and the second component 74 also remain unchanged.

[0087] Example 3

[0088] Figure 1-12 This invention illustrates a vehicle underbody structure. For example... Figure 1-12As shown, the vehicle's lower body structure includes a left longitudinal beam 1, a right longitudinal beam 2, a CTC battery pack assembly 3, and a rear floor assembly 4. The CTC battery pack assembly 3 includes battery cells and a front floor, with its two sides fixedly connected to the left longitudinal beam 1 and the right longitudinal beam 2, respectively. The front ends of the rear floor assembly 4 are fixedly connected to the left longitudinal beam 1 and the right longitudinal beam 2, respectively, and the fixed connection positions can be adjusted along the longitudinal direction of the vehicle body. The front center of the rear floor assembly 4 is fixedly connected to the rear end of the CTC battery pack assembly 3 via the connector 6 described above. The first direction is along the longitudinal direction of the vehicle body.

[0089] When adjusting the fixed connection position between the rear floor assembly 4 and the left longitudinal beam 1 and the right longitudinal beam 2, the rear wheel axle and corresponding suspension structure can be installed at the bottom of the rear floor assembly 4, thus enabling the adjustment of the vehicle wheelbase. While keeping the fixed connection position between the CTC battery pack assembly 3 and the left longitudinal beam 1 and the right longitudinal beam 2 unchanged, the gap between the rear floor assembly 4 and the CTC battery pack assembly 3 is compensated by rotating the connector 6, ensuring the sealing of the vehicle floor after the wheelbase is adjusted.

[0090] Based on the above structure, if the fixed connection position of the CTC battery pack assembly 3 with the left longitudinal beam 1 and the right longitudinal beam 2 is adjustable, and the position of the connector 6 fixed on the rear floor assembly 4 is adjustable, the vehicle wheelbase will have a large adjustable range.

[0091] like Figure 10 and Figure 11 As shown, a feasible structure for the left longitudinal beam 1 is illustrated. The structure of the right longitudinal beam 2 is symmetrical to that of the left longitudinal beam 1. The structures of the left longitudinal beam 1 and the right longitudinal beam 2 are described in detail below.

[0092] First, the connection structure between the longitudinal beam and the rear floor assembly 4 is described. A first bolt hole group 11 is provided at the end of the left longitudinal beam 1. The first bolt hole group 11 includes a plurality of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The first bolt hole group 11 is used for fixed connection to one front end of the rear floor assembly 4, and the number of bolt holes in the first bolt hole group 11 is greater than the corresponding number of bolt holes in the rear floor assembly 4. Similarly, a second bolt hole group is provided at the end of the right longitudinal beam 2. The second bolt hole group includes a plurality of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The second bolt hole group is used for fixed connection to one front end of the rear floor assembly 4, and the number of bolt holes in the second bolt hole group is greater than the corresponding number of bolt holes in the rear floor assembly 4.

[0093] During installation, by changing the specific fastening bolt holes used by the rear floor assembly 4 with the first bolt hole group 11 and the second bolt hole group, the fixed connection position between the rear floor assembly 4 and the left longitudinal beam 1 can be adjusted along the longitudinal direction of the vehicle body. For example, in Figure 10The first bolt hole group 11 shown in the diagram has five fastening bolt holes. Assuming that the rear floor assembly 4 has three bolt mounting holes corresponding to the left longitudinal beam 1 and the right longitudinal beam 2, when the rear floor assembly 4 is installed and fastened, the first three bolt holes, the middle three bolt holes, and the last three bolt holes of the left longitudinal beam 1 and the right longitudinal beam 2 are used in sequence, which will cause the rear floor assembly 4 to gradually move towards the rear of the vehicle relative to the left longitudinal beam 1, thereby achieving adjustment.

[0094] Next, the connection structure between the longitudinal beam and the CTC battery pack assembly 3 is described. A third bolt hole group 12 is provided in the middle of the left longitudinal beam 1. The third bolt hole group 12 includes a number of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The third bolt hole group 12 is used for fixed connection with one side of the CTC battery pack assembly 3, and the number of bolt holes in the third bolt hole group 12 is greater than the number of bolt holes corresponding to the CTC battery pack assembly 3.

[0095] Similarly, a fourth bolt hole group is provided in the middle of the right longitudinal beam 2. The fourth bolt hole group includes several bolt holes evenly spaced along the longitudinal direction of the vehicle body. The fourth bolt hole group is used to fix and connect to one side of the CTC battery pack assembly 3, and the number of bolt holes in the fourth bolt hole group is greater than the number of bolt holes corresponding to the CTC battery pack assembly 3.

[0096] Similar to the first bolt hole group 11 and the second bolt hole group, during installation, the CTC battery pack assembly 3 can be adjusted longitudinally along the vehicle body by adjusting the bolt holes that are fixed on the left longitudinal beam 1 and the right longitudinal beam 2.

[0097] The fixed connection positions of the CTC battery pack assembly 3 on the left longitudinal beam 1 and the right longitudinal beam 2 can be adjusted longitudinally along the vehicle body. By rotating and adjusting the connecting piece 6, the position of the base plate 61 fixed on the horizontal surface of the connecting plate 44 is adjusted longitudinally along the vehicle body. This, combined with the adjustment of the fixed position of the CTC battery pack assembly 3 on the left longitudinal beam 1 and the right longitudinal beam 2, allows the rear floor assembly 4 to have a larger adjustment range relative to the left longitudinal beam 1 and the right longitudinal beam 2, thereby further widening the vehicle wheelbase adjustment range.

[0098] Next, the connection structure between the longitudinal beams and the engine room assembly 5 is described. Since the engine room assembly 5 involves the installation of many components such as the cockpit, it is better designed so that its position relative to the longitudinal beams is not adjustable, and it is generally fixed by bolts. Specifically, a fifth bolt hole group 13 is provided at the front end of the left longitudinal beam 1, and a sixth bolt hole group is provided at the front end of the right longitudinal beam 2, for fixed connection with the rear sides of the engine room assembly 5.

[0099] Finally, the structure of the longitudinal beams themselves is described. This invention does not limit the structural style of the left longitudinal beam 1 and the right longitudinal beam 2, because theoretically, any longitudinal beam structure that can achieve the connection relationship with other components of this invention and meet the design requirements such as vehicle strength is acceptable. Figure 10and Figure 11 The left longitudinal beam 1 shown is only a schematic diagram of a feasible solution. The left longitudinal beam 1 includes an outer rectangular beam 101 and a smaller inner rectangular beam 102. The inner rectangular beam 102 has a first bolt hole group 11, a third bolt hole group 12, and a fifth bolt hole group 13 at both ends and in the middle. Additionally, Figure 10 The left longitudinal beam 1 structure is compared to Figure 5 The discrepancies are due to the removal of some connecting structures to the frame. Similar differences exist in the front and rear views of other components, but they do not affect the understanding of the invention.

[0100] like Figure 12 The diagram illustrates a feasible structure of the CTC battery pack assembly 3. The CTC battery pack assembly 3 utilizes CTC technology to integrate the front floor and seat crossbeam onto the upper cover of the battery pack; the battery pack employs square battery modules. CTC technology is currently developing rapidly and is widely used by OEMs such as BYD, Leapmotor, and Tesla, and will not be discussed in detail here. The following mainly describes the connection structure between the CTC battery pack assembly 3 and other components of this invention.

[0101] The entire CTC battery pack assembly 3 is rectangular, with several fixing lugs 31 on each outer side. Each fixing lug 31 has a mounting through hole for fixing to the connectors 6 on the left longitudinal beam 1, right longitudinal beam 2, rear floor assembly 4, and cabin assembly 5. Installation is typically achieved by driving in bolts. The mounting through holes on the fixing lugs 31 are threaded through holes. The bolt holes in the corresponding third bolt hole group 12 on the left longitudinal beam 1, the corresponding fourth bolt hole group on the right longitudinal beam 2, the corresponding mounting holes 621 on the rear floor assembly 4, and the corresponding mounting holes 621 on the cabin assembly 5 are all threaded blind holes. After the CTC battery pack assembly 3 is placed in position, a screw is screwed into the mounting through hole on each fixing lug 31 and finally tightened into the corresponding bolt hole in the corresponding third bolt hole group 12 on the left longitudinal beam 1, the corresponding fourth bolt hole group on the right longitudinal beam 2, the corresponding mounting hole 621 on the rear floor assembly 4, or the corresponding mounting hole 621 on the cabin assembly 5, thus achieving a fixed installation.

[0102] like Figure 6-9 The diagram illustrates a feasible structure for the rear floor assembly 4. First, the connection structure between the rear floor assembly 4 and the base plate 61 is described. The rear floor assembly 4 includes a rear floor body 41, with a connecting plate 44 at its front end. One side of the connecting plate 44 is horizontal, and this horizontal surface is used to adhere and fix the base plate 61 to the surface of the base plate. The position of the base plate 61 fixed to this horizontal surface can be adjusted longitudinally along the vehicle body. The adhesion and fixing of the two plates is easy to achieve, and the adjustment of the fixing position longitudinally along the vehicle body is convenient; it can be directly moved horizontally.

[0103] The position of the connector 6 fixed on the rear floor assembly 4 can be adjusted longitudinally along the vehicle body. This means the fixed position of the base plate 61 of the connector 6 on the rear floor assembly 4 is adjustable, allowing the connector 6 to be adjusted within a certain range in both its forward and reverse states. Therefore, during installation, when adjusting the longitudinal installation position of the rear floor assembly 4 relative to the left longitudinal beam 1 and the right longitudinal beam 2, rotating the connector 6, in conjunction with adjusting the position of the base plate 61 on the rear floor assembly 4 longitudinally, can compensate for the installation gap between the rear floor assembly 4 and the CTC battery pack assembly 3 caused by the adjustment of the rear floor assembly 4's position within a certain dimensional range. This results in a wider adjustable range for the vehicle's wheelbase, allowing for greater flexibility in actual wheelbase adjustment designs.

[0104] Furthermore, to ensure connection strength, the base plate 61 must completely overlap with the connecting plate 44 during adjustment. The connecting plate 44 can be designed with a width greater than the base plate 61 along the vehicle's longitudinal direction; this excess width defines the adjustable range. It should also be noted that adjusting the position of the base plate 61 on the connecting plate 44 along the vehicle's longitudinal direction does not affect the connection between the connector 6 and the CTC battery pack assembly 3; this can be easily achieved through structural design. The rear floor assembly 4 has a mounting surface that is fixedly connected to the first reinforcing plate 63. Figure 8 As shown, vertical plates are provided on both sides of the connecting plate 44 for fixed connection with the first reinforcing plate 63.

[0105] Next, the connection structure between the rear floor assembly 4 and the longitudinal beams is described. A left connecting beam 42 and a right connecting beam 43 are respectively provided on both sides of the front end of the rear floor body 41. The left connecting beam 42 is used to fix the end of the left longitudinal beam 1; the right connecting beam 43 is used to fix the end of the right longitudinal beam 2.

[0106] Finally, the structure of the rear floor body 41 is described. This invention does not limit the specific structure of the rear floor assembly 4, but only specifies its connection relationship with the floor 61, the left longitudinal beam 1, and the right longitudinal beam 2, in order to achieve the final adjustable vehicle wheelbase. Therefore, the specific structures given in 6-9 are only one feasible structure.

[0107] The bottom surface of the connecting plate 44 is fixedly connected to the base plate 61. The left connecting beam 42, the right connecting beam 43, and the connecting plate 44 are arranged in a U-shape; the two ends of the connecting plate 44 are located at the root bottom surfaces of the left connecting beam 42 and the right connecting beam 43. The outer surface of the main body of the left connecting beam 42 is inverted L-shape and is fixedly connected to the inner surface and top surface of the rear end of the left longitudinal beam 1; the outer surface of the main body of the right connecting beam 43 is inverted L-shape and is fixedly connected to the inner surface and top surface of the rear end of the right longitudinal beam 2. The L-shaped overlapping connection structure is more robust. The first bolt hole group 11 includes bolt holes located on the inner surface and top surface of the rear end of the left longitudinal beam 1.

[0108] like Figure 4 and Figure 5 As shown, the vehicle's lower body structure also includes an engine compartment assembly 5. The rear sides of the engine compartment assembly 5 are fixedly connected to the left longitudinal beam 1 and the right longitudinal beam 2, respectively, and the middle of the rear end is connected to the CTC battery pack assembly 3, forming a complete bottom frame structure.

[0109] To compensate for the gap caused by the movement of the CTC battery pack assembly 3, the rear center of the engine compartment assembly 5 is fixedly connected to the front end of the CTC battery pack assembly 3 via the connector 6 described above. The position of the connector 6 fixed to the engine compartment assembly 5 can be adjusted longitudinally along the vehicle body. In this way, the front and rear ends of the CTC battery pack assembly 3 are connected and transitioned via the connector 6, which can compensate for the larger gap caused by the movement of the CTC battery pack assembly 3, further enabling the vehicle to have a wider adjustable wheelbase range. The specific connection structure between the connector 6 and the engine compartment assembly 5 is similar to the connection structure with the rear floor assembly 4, and will not be described in detail here.

[0110] like Figure 1-3 As shown, in addition to the structure in Embodiment 1, the connecting member 6 needs to be reinforced according to the actual needs of the vehicle underbody structure of the present invention. Both sides of the bottom plate 61 are along the longitudinal direction of the vehicle body, and a first reinforcing plate 63 is provided on each side. The surface of the first reinforcing plate 63 is perpendicular to the bottom plate 61 and is used to fix it to the rear floor assembly 4. A second reinforcing plate 64 is also provided on the bottom plate 61. The surface of the second reinforcing plate 64 is perpendicular to the bottom plate 61, and both ends are fixed to a first reinforcing plate 63. A rib is provided between the second reinforcing plate 64 and the bottom plate 61.

[0111] The first reinforcing plate 63 and the second reinforcing plate 64 increase the structural strength of the entire connector 6 and the reliability of its connection with the rear floor assembly 4. The first reinforcing plate 63 can be triangular.

[0112] In addition, to further enhance the structure of the adapter, the ribs on it were planned and organized. For example... Figure 1 As shown, the surface of the second reinforcing plate 64 is arranged along the direction of the connecting units and is spaced at a certain distance; a connecting rib 651 is provided between the second reinforcing plate 64 and the boss 62 of each connecting unit. One side of the connecting rib 651 is fixed to the side of the boss 62, the other side is fixed to the second reinforcing plate 64, and the bottom edge is fixed to the base plate 61.

[0113] Each boss 62 is surrounded by four ribs arranged in a cross shape. These four ribs include connecting ribs 651, and two of the ribs have their surfaces aligned with the arrangement direction of the bosses 62. The ribs with their surfaces aligned with the arrangement direction of the bosses 62 connect to each other to form a combined rib 652 between two adjacent bosses 62. The two ribs with their surfaces aligned with the arrangement direction of the bosses 62 at both ends are respectively connected to the first reinforcing plate 63 on the corresponding side. The ribs between the second reinforcing plate 64 and the base plate 61 cross each other with a combined rib 652. This rib structure on the connector 6 is very easy to manufacture through casting, die casting, etc., and has high structural strength.

[0114] In addition, the cabin assembly 5, left longitudinal beam 1, right longitudinal beam 2, rear floor assembly 4, and connector 6 are all integrally die-cast. Connector 6 and rear floor assembly 4 are made of aluminum and are fixedly connected by riveting.

[0115] Traditional car body manufacturing involves stamping individual parts first, then welding them into a complete body assembly. A single vehicle is typically constructed from over 500 parts of varying shapes and materials. Before mass production, the entire vehicle undergoes three rounds of matching and debugging over six months, rigorously checking and solidifying the manufacturing status, materials, tooling, processes, product qualification rates, packaging, and transportation of these 500+ parts to ensure the final body quality meets assembly requirements. Recently, unibody die casting technology has emerged as a new trend in car body manufacturing. Unibody die casting involves a single molding process, eliminating the complex stamping and welding steps. This simplifies the manufacturing process, requiring only one part and eliminating the need for extensive tooling and the accumulation of errors from connecting numerous parts. Manufacturing precision is controllable. The elimination of the need to inspect the manufacturing status of each individual part not only shortens the complex car body manufacturing process but also significantly reduces manufacturing costs.

[0116] For convenience, the left longitudinal beam 1 and the right longitudinal beam 2 are collectively referred to as longitudinal beams. In summary, when adjusting the vehicle wheelbase using the above-described vehicle underbody structure, since the fixed position of the engine compartment assembly 5 on the longitudinal beam cannot be adjusted, that is, the position of the vehicle's front wheel axle relative to the longitudinal beam remains unchanged, the installation position of the rear floor assembly 4 on the longitudinal beam is first adjusted through the first bolt hole group 11 and the second bolt hole group to bring the vehicle wheelbase to the set value; then, by adjusting the position and rotation of one connector 6 on the rear floor assembly 4, adjusting the position of the CTC battery pack assembly 3 on the longitudinal beam, and adjusting the position and rotation of another connector 6 on the engine compartment assembly 5, the longitudinal gaps between the various mounting components caused by the adjustment of the rear floor assembly 4 can be compensated, ensuring reliable floor sealing.

[0117] Example 4

[0118] Figure 13This invention illustrates a method for adjusting the wheelbase of a vehicle based on the aforementioned vehicle underbody structure, comprising: adjusting the position of the front end of the rear floor assembly 4, which is fixedly connected to the left longitudinal beam 1 and the right longitudinal beam 2, along the longitudinal direction of the vehicle body, and eliminating the gap between the front end of the rear floor assembly 4 and the rear end of the CTC battery pack assembly 3 caused by the position adjustment using a first method; wherein, the first method includes ① rotating the connector 6 fixed to the rear floor assembly 4 by 180° around a first axis. Here, it refers to the connector 6 rotating 180° around its own first axis.

[0119] Optionally, the first method further includes: ② adjusting the connection 6 fixed on the rear floor assembly 4 along the longitudinal direction of the vehicle body; ③ adjusting the fixed connection position of the CTC battery pack assembly 3 on the left longitudinal beam 1 and the right longitudinal beam 2 along the longitudinal direction of the vehicle body; ④ rotating the connection 6 fixed on the engine compartment assembly 5 around the first axis by 180°; and ⑤ adjusting the connection 6 fixed on the engine compartment assembly 5 along the longitudinal direction of the vehicle body.

[0120] It should be noted that the specific operation methods ①-⑤ in the first method above are independent of each other. During a vehicle wheelbase adjustment process, any one or any combination of the first methods can be used to eliminate the gap between the front end of the rear floor assembly 4 and the rear end of the CTC battery pack assembly 3 caused by the position adjustment.

[0121] To more vividly illustrate the process of adjusting the vehicle's wheelbase, such as Figure 13 As shown, the various components of the vehicle's lower body structure are abstracted, retaining only their dimensions and relative positional relationships along the vehicle's axial direction. Figure 13 In the diagram, a dashed line indicates a fixed connection between two components. A range with dimensions marked at one end of the dashed line indicates that the fixed connection between the two components is adjustable. A range without dimensions marked at both ends of the dashed line indicates that the fixed connection between the two components is not adjustable.

[0122] For example, in Figure 13 In this context, 'a' represents the adjustable range of the rear floor assembly 4's fixed position on the left longitudinal beam 1 and right longitudinal beam 2 along the longitudinal direction of the vehicle body. Since the left longitudinal beam 1 and right longitudinal beam 2 are connected to and have their positions adjusted by bolt holes, 'a' is a set of point values, such as 30mm, 50mm, 100mm, and 150mm. Note that the adjustment value here is the difference from the minimum wheelbase. If the minimum wheelbase is 2800mm, then the corresponding adjustable wheelbases are: 2800mm, 2830mm, 2850mm, 2900mm, and 2950mm.

[0123] b represents the adjustable range of the fixed position of the base plate 61 on the rear connecting plate 44 along the longitudinal direction of the vehicle body. It is a continuous range with the base plate 61 fixed at the foremost position of the connecting plate 44 as the zero reference. For example, b can be 0 or 100 mm.

[0124] c represents the adjustable range of the fixed position of the CTC battery pack assembly 3 on the left longitudinal beam 1 along the longitudinal direction of the vehicle body. The zero reference is the position of the CTC battery pack assembly 3 fixed at the front end of the left longitudinal beam 1, which is a continuous range. For example, c can be 0 or 100 mm.

[0125] Furthermore, the connecting pieces 6 on the rear floor assembly 4 and the engine compartment assembly 5 can be adjusted by a fixed value d along the longitudinal direction of the vehicle body by rotating about their respective first axes. For example, assuming the connecting piece 6 on the rear floor assembly 4 is positioned as follows... Figure 13 In the arrangement shown, with the connecting structure at the front, the positions of other components remain unchanged. By rotating the connecting piece 6 180° around the first axis, the fixed connection between the base plate 61 and the rear floor assembly 4 remains unchanged, but there will be a gap between the rear end of the CTC battery pack assembly 3 and the connecting structure. To compensate for this gap, the position of the rear floor assembly 4 fixed on the longitudinal beam can be moved forward to reduce the wheelbase. Alternatively, the methods of moving the CTC battery pack assembly 3 and the rear cabin assembly 5 can be combined to keep the wheelbase variable.

[0126] In summary, after adjusting the position of the rear floor assembly 4 mounted on the longitudinal beams to achieve wheelbase adjustment, the following methods can be used: ① rotating the connector 6 fixed on the rear floor assembly 4 180° around the first axis; ② moving the connector 6 fixed on the rear floor assembly 4 along the longitudinal direction of the vehicle body; ③ adjusting the fixed connection position of the CTC battery pack assembly 3 on the left longitudinal beam 1 and the right longitudinal beam 2 along the longitudinal direction of the vehicle body; ④ rotating the connector 6 fixed on the engine compartment assembly 5 180° around the first axis; ⑤ moving the connector 6 fixed on the engine compartment assembly 5 along the longitudinal direction of the vehicle body. Any one or any combination of these five methods can be used to achieve matching adjustment and ensure the integrity of the floor.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A vehicle underbody structure, characterized in that, Includes left longitudinal beam (1), right longitudinal beam (2), CTC battery pack assembly (3) and rear floor assembly (4); The two sides of the CTC battery pack assembly (3) are fixedly connected to the left longitudinal beam (1) and the right longitudinal beam (2), respectively. The front ends of the rear floor assembly (4) are fixedly connected to the left longitudinal beam (1) and the right longitudinal beam (2) respectively, and the fixed connection position can be adjusted along the longitudinal direction of the vehicle body; the front middle of the rear floor assembly (4) is fixedly connected to the rear end of the CTC battery pack assembly (3) through the connector (6); the first direction is along the longitudinal direction of the vehicle body; The connector (6) includes a base plate (61) and a connecting structure disposed on the surface of the base plate (61); the base plate (61) is a centrally symmetrical structure and is used for fixed connection with the first component; the connecting structure is used for fixed connection with the second component. If the connecting structure is rotated 180° around the first axis, the position state of the connecting structure after rotation can be translated along the first direction to coincide with the position state before rotation; the first axis passes through the center of symmetry of the base plate (61) and is perpendicular to the surface of the base plate (61), and the first direction is parallel to the surface of the base plate (61); When the first component and the second component are connected using the connector (6), two connection states can be formed, in which the first component and the second component are in different relative positions in the first direction.

2. The vehicle underbody structure according to claim 1, characterized in that, The connection structure includes several connection units, which are evenly spaced and arranged on one side of the center of symmetry of the base plate (61).

3. The vehicle underbody structure according to claim 2, characterized in that, The arrangement direction of the plurality of connecting units is perpendicular to the first direction.

4. The vehicle underbody structure according to claim 2, characterized in that, The connecting unit includes a boss (62) on one side of the base plate (61), and the top surface of the boss (62) has a mounting hole (621) for fixed connection with the second component.

5. A vehicle underbody structure according to claim 1, characterized in that, The position of the connector (6) fixed on the rear floor assembly (4) can be adjusted along the longitudinal direction of the vehicle body.

6. The vehicle underbody structure according to claim 1, characterized in that, The end of the left longitudinal beam (1) is provided with a first bolt hole group (11). The first bolt hole group (11) includes a plurality of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The first bolt hole group (11) is used to fix and connect to the front end side of the rear floor assembly (4). The number of bolt holes in the first bolt hole group (11) is greater than the number of bolt holes corresponding to the rear floor assembly (4).

7. A vehicle underbody structure according to claim 1, characterized in that, The fixed connection position of the CTC battery pack assembly (3) on the left longitudinal beam (1) and the right longitudinal beam (2) can be adjusted along the longitudinal direction of the vehicle body.

8. A vehicle underbody structure according to claim 7, characterized in that, It also includes a cabin assembly (5), the rear ends of which are fixedly connected to the left longitudinal beam (1) and the right longitudinal beam (2) respectively; the rear middle of the cabin assembly (5) is fixedly connected to the front end of the CTC battery pack assembly (3) through the connector (6).

9. A vehicle underbody structure according to claim 8, characterized in that, The position of the connector (6) fixed on the cabin assembly (5) can be adjusted along the longitudinal direction of the vehicle body.

10. A vehicle underbody structure according to claim 7, characterized in that, A third bolt hole group (12) is provided in the middle of the left longitudinal beam (1). The third bolt hole group (12) includes a number of bolt holes evenly spaced along the longitudinal direction of the vehicle body. The third bolt hole group (12) is used to fix and connect to one side of the CTC battery pack assembly (3). The number of bolt holes in the third bolt hole group (12) is greater than the number of bolt holes corresponding to the CTC battery pack assembly (3).

11. A vehicle underbody structure according to claim 1, characterized in that, Both sides of the base plate (61) are along the longitudinal direction of the vehicle body, and a first reinforcing plate (63) is provided on each side; the surface of the first reinforcing plate (63) is perpendicular to the base plate (61) and is used to be fixedly connected to the rear floor assembly (4); The base plate (61) is also provided with a second reinforcing plate (64), the surface of the second reinforcing plate (64) is perpendicular to the base plate (61), and both ends are fixed to a first reinforcing plate (63); a rib is provided between the second reinforcing plate (64) and the base plate (61).

12. A method for adjusting the wheelbase of a vehicle based on the vehicle underbody structure according to any one of claims 1-11, characterized in that, include: The position of the front end of the rear floor assembly (4) fixedly connected to the left longitudinal beam (1) and the right longitudinal beam (2) is adjusted along the longitudinal direction of the vehicle body, and the gap between the front end of the rear floor assembly (4) and the rear end of the CTC battery pack assembly (3) due to the position adjustment is eliminated by the first method. The first method includes rotating a connector (6) fixed to the rear floor assembly (4) 180° about a first axis.

13. A method for adjusting vehicle wheelbase according to claim 12, characterized in that, The first method further includes: adjusting the connection (6) fixed on the rear floor assembly (4) along the longitudinal direction of the vehicle body; adjusting the fixed connection position of the CTC battery pack assembly (3) on the left longitudinal beam (1) and the right longitudinal beam (2) along the longitudinal direction of the vehicle body; rotating the connection (6) fixed on the engine compartment assembly (5) 180° around the first axis; and adjusting the connection (6) fixed on the engine compartment assembly (5) along the longitudinal direction of the vehicle body.

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