A rear floor assembly, a rear body assembly, and a vehicle thereof

Abstract

This application relates to a rear floor assembly, a rear body assembly, and a vehicle thereof, comprising: a front section and a rear section, the front section including a rear casting body; the rear section is detachably connected to the front section, and the rear section includes a separately disposed left rear longitudinal beam assembly and a right rear longitudinal beam assembly; wherein the left and right rear longitudinal beam assemblies are fixed to the rear casting body by a detachable connection structure. This invention divides the rear floor assembly into a front section and a rear section, employing a detachable connection structure between the two and between the longitudinal beams and the rear casting body, thus achieving a modular distribution of the rear floor structure. In the event of a rear-end collision, the damage is typically concentrated in the rear area of ​​the vehicle body. Because the rear section and the front section are detachable, during repairs, only the damaged rear section needs to be removed from the front section, without needing to cut or replace the entire rear casting body, allowing the rear casting body to be preserved undamaged.

Description

Technical Field

[0001] This application relates to the automotive field, and in particular to a rear floor assembly, a rear body assembly, and a vehicle thereof. Background Technology

[0002] With the rapid development of the new energy vehicle industry, vehicle lightweighting has become a key technological means to improve vehicle range and performance. Integrated die-casting technology, due to its ability to significantly reduce the number of parts, simplify the manufacturing process, and reduce vehicle weight, is increasingly being applied to the manufacture of large structural components such as the rear floor. Currently, more and more vehicle models tend to use large integrated aluminum die-cast parts as the rear floor assembly to achieve overall vehicle weight reduction and structural simplification.

[0003] However, existing integrated die-cast rear floor structures suffer from high maintenance costs and complex molding processes in practical applications. Because the rear floor is a single large casting, even low- or medium-speed rear-end collisions often require replacing the entire large casting, leading to extremely high repair costs. Furthermore, the ultra-large integrated die-cast parts place extremely high demands on the tonnage of the die-casting equipment and the design and manufacturing precision of the molds, which not only increases the manufacturing cost of the parts but also raises the difficulty and barriers to entry in the production process.

[0004] Meanwhile, in existing technical solutions, the connection between the aluminum rear floor assembly and other steel parts assemblies in the body-in-white (such as side panels and front floor) usually involves dissimilar material joining processes. This requires large-scale modifications to existing production lines or the investment in new joining equipment, increasing the investment cost of vehicle development. In addition, the steel-aluminum connection points are prone to corrosion risks due to electrochemical corrosion and water accumulation in the gaps. Summary of the Invention

[0005] This application provides a rear floor assembly, a rear body assembly, and a vehicle thereof, which can solve the problem of poor maintainability of large die-cast rear floor structures in related technologies.

[0006] In a first aspect, embodiments of this application provide a rear floor assembly, which includes: a front section and a rear section, the front section including a rear casting body; the rear section is detachably connected to the front section, the rear section including a left rear longitudinal beam assembly and a right rear longitudinal beam assembly separately disposed therefrom; wherein the left rear longitudinal beam assembly and the right rear longitudinal beam assembly are fixed to the rear casting body by a detachable connection structure.

[0007] In conjunction with the first aspect, in one embodiment, the rear section of the assembly further includes a rear load-bearing floor assembly; The rear casting body, the left rear longitudinal beam assembly, and the right rear longitudinal beam assembly are arranged to form a semi-enclosed structure, and the rear load-bearing floor assembly is disposed between the rear casting body, the left rear longitudinal beam assembly, and the right rear longitudinal beam assembly.

[0008] In conjunction with the first aspect, in one embodiment, there is a height difference between the top surface of the rear bearing floor assembly and the top surface of the rear casting body, a height difference between the top surface of the rear bearing floor assembly and the top surface of the left rear longitudinal beam assembly, and a height difference between the top surface of the rear bearing floor assembly and the top surface of the right rear longitudinal beam assembly, so that a spare tire pit for the rear floor is formed on the rear section of the assembly.

[0009] In conjunction with the first aspect, in one embodiment, the rear floor spare tire recess is used to accommodate a flip-up seat; The depth of the spare tire pit in the rear floor is greater than or equal to a first set threshold, and the closed thickness of the flip-up seat is less than the first set threshold. The opening width of the spare tire pit in the rear floor is greater than or equal to the second set threshold, and the width of the flip-up seat is less than the second set threshold. The length of the spare tire well in the rear floor is greater than or equal to a third set threshold, and the backrest length of the flip-up seat is less than the third set threshold.

[0010] In conjunction with the first aspect, in one embodiment, the top surface of the rear support floor assembly is provided with a top support member, the top of which is used to support the flip-up seat.

[0011] In conjunction with the first aspect, in one embodiment, the rear load-bearing floor assembly is made of steel sheet metal; The rear casting body, the left rear longitudinal beam assembly, and the right rear longitudinal beam assembly are all made of aluminum.

[0012] In conjunction with the first aspect, in one embodiment, a drainage structure is provided between the rear casting body and the rear load-bearing floor assembly, and between the rear casting body and the vehicle side panel structure.

[0013] In conjunction with the first aspect, in one embodiment, the rear casting body and the rear load-bearing floor assembly, and the rear casting body and the vehicle side panel structure are connected by a connecting structure.

[0014] In conjunction with the first aspect, in one embodiment, the connection structure includes structural adhesive and connectors; The rear casting body and the rear load-bearing floor assembly, and the rear casting body and the vehicle side panel structure are fixed together by structural adhesive; The rear casting body and the rear load-bearing floor assembly are also fixed together by connectors.

[0015] In conjunction with the first aspect, in one embodiment, the rear casting body is provided with a rear floor reinforcement beam, the rear floor reinforcement beam being made of aluminum.

[0016] In conjunction with the first aspect, in one embodiment, the front section of the assembly further includes: a rear section assembly structure of the sill inner panel, a rear floor connecting plate, a front connecting plate assembly of the rear longitudinal beam, a middle panel assembly of the rear floor, and a front connecting plate assembly of the rear floor. The rear section assembly structure of the sill inner panel is connected to the rear casting body; the rear floor connecting plate is connected to the rear casting body; the front connecting plate assembly of the rear longitudinal beam is connected to the rear casting body; the middle panel assembly of the rear floor is connected to the rear casting body; and the front connecting plate assembly of the rear floor is connected to the rear casting body.

[0017] In conjunction with the first aspect, in one embodiment, the rear section assembly structure of the inner sill plate, the rear floor connecting plate, and the front connecting plate assembly of the rear longitudinal beam are disposed on both sides of the rear casting body along the left-right direction of the vehicle body. The rear floor center panel assembly and the rear floor front connecting plate assembly are respectively located on both sides of the rear casting body along the front-rear direction of the vehicle body.

[0018] In conjunction with the first aspect, in one embodiment, the rear section assembly structure of the sill inner panel includes a left sill inner panel rear section assembly and a right sill inner panel rear section assembly, which are respectively disposed on both sides of the rear casting body along the left-right direction of the vehicle body.

[0019] In conjunction with the first aspect, in one embodiment, the rear floor connecting plate includes: a rear floor left front connecting plate, a rear floor left middle connecting plate, a rear floor left rear connecting plate, a rear floor right rear connecting plate, a rear floor right middle connecting plate, and a rear floor right front connecting plate. The rear floor left front connecting plate, rear floor left middle connecting plate, and rear floor left rear connecting plate are located on one side of the rear casting body along the left-right direction of the vehicle body, and the rear floor right rear connecting plate, rear floor right middle connecting plate, and rear floor right front connecting plate are located on the other side of the rear casting body along the left-right direction of the vehicle body.

[0020] In conjunction with the first aspect, in one embodiment, the rear longitudinal beam front connecting plate assembly includes a left rear longitudinal beam front connecting plate and a right rear longitudinal beam front connecting plate, the left rear longitudinal beam front connecting plate and the right rear longitudinal beam front connecting plate being respectively disposed on both sides of the rear casting body along the left-right direction of the vehicle body.

[0021] In conjunction with the first aspect, in one embodiment, the left rear longitudinal beam assembly includes a left rear longitudinal beam body, and the left rear longitudinal beam body is provided with a left rear longitudinal beam end plate and a left rear longitudinal beam connecting plate. The right rear longitudinal beam assembly includes a right rear longitudinal beam body, on which a right rear longitudinal beam end plate and a right rear longitudinal beam connecting plate are provided.

[0022] In conjunction with the first aspect, in one embodiment, the rear section assembly of the inner sill plate, the rear floor connecting plate, the rear longitudinal beam front connecting plate assembly, the left rear longitudinal beam connecting plate, the right rear longitudinal beam connecting plate, and the rear floor front connecting plate assembly are made of steel sheet metal parts.

[0023] Secondly, embodiments of this application provide a rear vehicle body assembly, which includes: As described above, the rear floor assembly, rear bulkhead assembly, and rear bumper beam assembly are all connected together. The rear bulkhead assembly is fixed to the rear floor assembly via a detachable connection structure, and the rear bumper beam assembly is fixed to the rear bulkhead assembly via a detachable connection structure.

[0024] In conjunction with the second aspect, in one embodiment, the rear floor assembly includes a front section and a rear section. The front section of the assembly includes a rear casting body, and the rear section of the assembly includes a rear load-bearing floor assembly, a separately arranged left rear longitudinal beam assembly, and a right rear longitudinal beam assembly; The rear casting body, left rear longitudinal beam assembly, right rear longitudinal beam assembly and rear bulkhead assembly form an enclosing structure, and the rear load-bearing floor assembly is disposed between the rear casting body, left rear longitudinal beam assembly, right rear longitudinal beam assembly and rear bulkhead assembly.

[0025] Thirdly, embodiments of this application provide a vehicle comprising: the rear body assembly as described above.

[0026] The beneficial effects of the technical solutions provided in this application include: This application provides a rear floor assembly, a rear body assembly, and a vehicle thereof. By dividing the rear floor assembly into a front section and a rear section, and employing a detachable connection structure between the two and between the longitudinal beams and the rear casting body, a modular distribution of the rear floor structure is achieved. In the event of a rear-end collision, the collision damage is typically concentrated in the rear area of ​​the vehicle body. Because the rear section and the front section of the assembly are detachable, during maintenance, only the damaged rear section can be removed from the front section without cutting or replacing the entire rear casting body. This allows the rear casting body to be preserved undamaged.

[0027] Meanwhile, the rear section of the assembly features separate left and right rear longitudinal beam assemblies, further subdividing the rear structure into independent repair units on the left and right. In the event of an offset collision resulting in damage to one side of the longitudinal beam, the damaged side of the longitudinal beam assembly can be disassembled and replaced individually, while the intact longitudinal beam assembly on the other side can continue to be used. This structural layout reduces the range of parts that need to be replaced during collision repairs and lowers the likelihood of replacing the entire structural component due to localized damage, thus providing structural advantages for reducing repair complexity. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the rear vehicle body assembly provided in an embodiment of this application; Figure 2 An exploded view of the rear vehicle body assembly provided in an embodiment of this application; Figure 3 A schematic diagram of the rear floor assembly provided in an embodiment of this application; Figure 4 A schematic diagram of the rear floor assembly provided in an embodiment of this application; Figure 5 A schematic diagram of the rear floor assembly provided in an embodiment of this application; Figure 6 This is a schematic diagram of the conventional state of the flip-up seat provided in the embodiments of this application; Figure 7 This is a schematic diagram of the flip-up seat in its flipped state, provided in an embodiment of this application. Figure 8 A schematic diagram of the rear floor assembly provided in an embodiment of this application; Figure 9 for Figure 8 Sectional view at point AA; Figure 10 A schematic diagram of the rear floor assembly provided in an embodiment of this application; Figure 11 This is an exploded view of the rear floor assembly provided in an embodiment of this application; Figure 12 This is a schematic diagram of the location of the drainage structure provided in an embodiment of this application; Figure 13 for Figure 12 Enlarged view of point B in the middle; Figure 14 for Figure 12 Enlarged diagram at point F; Figure 15 for Figure 12 Enlarged diagram of point G in the middle; Figure 16 This is a sectional view of point B (A1-A1), point F (A2-A2), and point G (A3-A3). Figure 17 for Figure 12 Enlarged view of point C in the middle; Figure 18 for Figure 12 Sectional view at point BB; Figure 19 for Figure 12 Enlarged view of point D; Figure 20 for Figure 12 Enlarged view of point E in the middle; Figure 21 for Figure 20 Sectional view at CC; Figure 22 This is a schematic diagram of the left rear longitudinal beam assembly provided in an embodiment of this application.

[0030] In the diagram: 1. Rear floor assembly; 10. Front section of assembly; 100. Rear casting body; 101. Rear floor center reinforcing beam; 102. Rear sill inner panel assembly structure; 1021. Rear section of left sill inner panel assembly; 1022. Rear section of right sill inner panel assembly; 103. Rear floor connecting plate; 1031. Rear floor left front connecting plate; 1032. Rear floor left center connecting plate; 1033. Rear floor left rear connecting plate; 1034. Rear floor right rear connecting plate; 1035. Rear floor right center connecting plate; 1036. Rear floor right front connecting plate; 104. Rear longitudinal beam front connecting plate assembly; 1041. Left rear longitudinal beam. 1042. Front connecting plate; 105. Right rear longitudinal beam front connecting plate; 106. Rear floor center panel assembly; 11. Rear floor front connecting plate assembly; 11. Rear section of assembly; 110. Left rear longitudinal beam assembly; 1101. Left rear longitudinal beam body; 1102. Left rear longitudinal beam end plate; 1103. Left rear longitudinal beam connecting plate; 111. Rear load-bearing floor assembly; 112. Right rear longitudinal beam assembly; 2. Rear bulkhead assembly; 3. Rear bumper beam assembly; 4. Flip-up seat; 5. Carpet; 6. Connecting structure; 60. Structural adhesive; 61. Connector; 7. Drainage structure; 8. Left wheel arch D-pillar inner panel; 9. Left wheel arch C-pillar inner panel. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] This application provides a rear floor assembly, a rear body assembly, and a vehicle thereof, which can solve the problem of poor maintainability of large die-cast rear floor structures in related technologies.

[0033] See Figures 1-22In a first aspect, embodiments of this application provide a rear floor assembly, comprising: a front section 10 and a rear section 11. The front section 10 includes a rear casting body 100. The rear section 11 is detachably connected to the front section 10, and includes a separately disposed left rear longitudinal beam assembly 110 and a right rear longitudinal beam assembly 112. The left and right rear longitudinal beam assemblies 110 and 112 are fixed to the rear casting body 100 via a detachable connection structure. The rear casting body 100, as the main load-bearing frame in the rear of the vehicle body, is formed using an integrated aluminum alloy die-casting process, ensuring the strength and rigidity of the main structure while reducing the number of parts. Both the left and right rear longitudinal beam assemblies 110 and 112 are made of extruded aluminum profiles to reduce molding difficulty and achieve lightweighting. The profile structure facilitates dimensional adjustments in the length direction to adapt to different vehicle models. The detachable connection structure can specifically employ bolted connection components, secured through pre-set mounting holes, allowing for non-destructive disassembly when needed. The connection location is typically situated at the lap flange edge between the longitudinal beam assembly and the front casting, ensuring reliable connection. It is also surrounded by steel sheet metal components to achieve compatibility with traditional steel body production lines, but the core load-bearing structure retains the aforementioned aluminum segmented layout.

[0034] This application achieves a modular distribution of the rear floor structure by dividing the rear floor assembly 1 into a front section 10 and a rear section 11, and employing a detachable connection structure between the two and between the longitudinal beam and the rear casting body 100. In the event of a rear-end collision, the damage is typically concentrated in the rear of the vehicle. Since the rear section 11 is detachable from the front section 10, during repairs, only the damaged rear section 11 can be removed from the front section 10 without cutting or replacing the entire rear casting body 100. The rear casting body 100 is typically located in front of the crumple zone; if no plastic deformation occurs, it can be preserved undamaged. This design avoids the scrapping of large die-cast parts due to localized collisions, reduces waste of precious metal materials, and eliminates the need for large cutting equipment to replace the rear section, simplifying the repair process and reducing the risk of reduced body strength due to the heat-affected zone of welding.

[0035] Meanwhile, the rear section 11 of the assembly adopts separate left and right rear longitudinal beam assemblies 110 and 112, further subdividing the rear structure into independent maintenance units on the left and right sides. In the event of an offset collision resulting in damage to one side of the longitudinal beam, the damaged longitudinal beam assembly can be removed and replaced individually, while the intact longitudinal beam assembly on the other side can continue to be used. This structural layout reduces the range of parts that need to be replaced during collision repairs and lowers the possibility of replacing the entire structural component due to localized damage, thus providing conditions for reducing maintenance complexity at the structural level. Furthermore, the separate longitudinal beam structure also provides space for the depth design of the spare tire well area, facilitating the arrangement of the subsequent seat storage structure, allowing the third-row seats to be folded into the well, achieving a synergistic optimization of maintainability and space utilization, and enhancing the vehicle's functional versatility. The depth and width design of the spare tire well must meet the accommodation requirements after the seats are closed, ensuring that the seats are flush with the floor surface when folded, without occupying additional luggage space.

[0036] This application divides the rear floor assembly 1 into two sections, as follows: Figure 3 As shown, Figure 3 As shown, the front section 10 of the assembly includes a rear casting body 100, which is formed by an integrated die-casting process and constitutes the main load-bearing frame of the rear of the vehicle body, possessing high structural integrity and rigidity. The rear section 11 of the assembly consists of a left rear longitudinal beam assembly 110 and a right rear longitudinal beam assembly 112, with the main structural material being aluminum extrusion profiles. Aluminum extrusion profiles have the characteristics of constant cross-section, high production efficiency, and relatively low mold cost, making them suitable for longitudinal beam structures requiring standardized production. A detachable connection structure (e.g., bolted connection) is used between the front section 10 and the rear section 11 of the assembly. The connection interface is located at the lap flange edge of the longitudinal beam assembly and the front casting, and is secured by a connector 61 passing through a pre-set mounting hole, with structural adhesive 60 filling the gaps to ensure sealing. This reduces the cost of repairing large castings, and the use of aluminum extrusion profile longitudinal beams also reduces parts cost and the difficulty of forming large castings. In the event of a rear-end collision, the collision energy is transmitted rearward along the longitudinal beams, and the damage is usually concentrated in the rear area. Thanks to its detachable connection structure, during repairs, only the damaged rear section 11 of the assembly can be removed from the front section 10, without cutting or replacing the entire rear casting body 100. For low-speed collisions, only the rear bumper beam may need to be replaced; for medium-speed collisions, the left rear longitudinal beam assembly 110 or the right rear longitudinal beam assembly 112 can be replaced separately; for high-speed collisions, the entire rear section 11 can be replaced while the intact rear casting body 100 remains intact. This segmented modular design avoids the complete scrapping of large die-cast parts due to localized damage, reduces cutting and welding processes during repairs, lowers the risk of reduced body strength due to heat-affected zones, and also reduces the waste of precious metal materials, significantly reducing repair costs. Furthermore, the replacement of the rear section parts can be completed without the need for large cutting equipment, simplifying the repair process.

[0037] Furthermore, a rear floor reinforcement beam 101 is provided on the rear casting body 100, and the rear floor reinforcement beam 101 is made of aluminum. The rear casting body 100, the left rear longitudinal beam assembly 110, and the right rear longitudinal beam assembly 112 are all made of aluminum. The left rear longitudinal beam assembly 110 includes a left rear longitudinal beam body 1101, on which a left rear longitudinal beam end plate 1102 and a left rear longitudinal beam connecting plate 1103 are provided. The right rear longitudinal beam assembly 112 includes a right rear longitudinal beam body, on which a right rear longitudinal beam end plate and a right rear longitudinal beam connecting plate are provided. The left rear longitudinal beam connecting plate 1103 and the right rear longitudinal beam connecting plate are made of steel sheet metal. The rear floor reinforcement beam 101 and the rear casting body 100 are integrally die-cast, spanning between the left and right longitudinal beams. This enhances the lateral connection stiffness of the front section 10 of the assembly, ensures the continuity of force transmission between the left and right longitudinal beams, and improves the torsional stiffness of the vehicle body. The left and right rear longitudinal beam bodies 1101 and 1103, as the main collision energy absorption and force transmission components, are made of extruded aluminum profiles to ensure lightweight and cross-sectional performance. Their internal multi-cavity structures can be designed to optimize energy absorption efficiency. The left and right rear longitudinal beam connecting plates 1103 and 1103 are located at the ends of the longitudinal beam assembly. As interface components connecting to other structures of the vehicle body, they are made of steel sheet metal to facilitate welding connections with the steel structures of the front or side sections of the vehicle body. This achieves a smooth transition between dissimilar material assemblies and avoids the process difficulties caused by directly connecting aluminum with non-matching steel parts.

[0038] Specifically, such as Figure 5 As shown, this application utilizes a segmented design, employing different material combinations in different segments to enhance the performance of the rear floor assembly 1. A cross-sectional aluminum structure is used in key load-bearing locations, while steel sheet metal is used in other non-key load-bearing locations, maximizing weight reduction of the rear floor assembly 1 while improving performance. This segmented design divides areas based on the mechanical characteristics of the vehicle body structure, identifying critical areas along the collision force transmission path as aluminum application zones. Cross-sectional aluminum structures typically refer to extruded profiles or die-cast integrated structures with specific geometric shapes, which can improve bending and torsional resistance through cross-sectional shape optimization. In contrast, steel sheet metal is used in other non-key load-bearing locations, utilizing the high ductility and mature stamping technology to create cover parts or connecting transition parts. This hybrid material arrangement avoids the high cost and difficult connection issues of all-aluminum structures, and overcomes the heavy weight of all-steel structures, maximizing weight reduction of the rear floor assembly 1 while improving performance, thus achieving optimal vehicle body structural efficiency.

[0039] like Figure 5As shown in this application, the left rear longitudinal beam body 1101 in the left rear longitudinal beam assembly 110, the right rear longitudinal beam body in the right rear longitudinal beam assembly 112, the rear casting body 100, and the rear floor reinforcement beam 101 are designed as aluminum components. Replacing steel with aluminum reduces the weight of the rear floor assembly 1, improving lightweighting. Other parts are designed as steel sheet metal parts. These aluminum components constitute the core load-bearing skeleton of the rear floor assembly 1. The rear casting body 100 provides basic support, the rear floor reinforcement beam 101 enhances lateral stiffness, and the left and right rear longitudinal beam bodies 1101 and 1101 are responsible for transmitting and absorbing longitudinal forces. Aluminum has a lower density than steel. While meeting the same strength requirements, replacing steel with aluminum reduces the weight of the rear floor assembly 1, improving lightweighting and thus reducing overall vehicle energy consumption. Other parts are designed as steel sheet metal parts. These steel parts are typically arranged around the aluminum parts or at connection interfaces to achieve steel-to-steel connections with other body structures, ensuring production line compatibility. The steel sheet metal parts also serve to protect the internal aluminum structure, and the sealing process at the steel-aluminum joint area prevents corrosion caused by potential difference, thus ensuring the service life of the hybrid material body.

[0040] Based on the above embodiments, in this embodiment, the rear section 11 of the assembly further includes a rear load-bearing floor assembly 111; the rear casting body 100, the left rear longitudinal beam assembly 110, and the right rear longitudinal beam assembly 112 form a semi-enclosed structure, and the rear load-bearing floor assembly 111 is disposed between the rear casting body 100, the left rear longitudinal beam assembly 110, and the right rear longitudinal beam assembly 112. The rear load-bearing floor assembly 111 serves as the main covering component forming the bottom of the spare tire pit, and its edges are fixed to the rear casting body 100 through a connecting structure 6. The connecting structure 6 includes structural adhesive 60 and connectors 61. The structural adhesive 60 fills the gaps in the overlapping flange edges to ensure sealing and connection rigidity, and the connectors 61 pass through the reserved mounting holes for fastening. The semi-enclosed structure refers to the enclosure formed on the left and right sides and rear of the vehicle body. This layout not only ensures structural strength, but also leaves space for the middle area to sink, so that the rear load-bearing floor assembly 111 can be suspended under the longitudinal beams, thereby providing vertical space for seat storage. At the same time, the left rear longitudinal beam assembly 110 and the right rear longitudinal beam assembly 112 are both made of aluminum extrusion profiles to reduce molding difficulty and achieve lightweight. Furthermore, the rear casting body 100 is provided with a rear floor central reinforcing beam 101 to enhance lateral rigidity and ensure the continuity of force transmission between the left and right longitudinal beams.

[0041] The rear load-bearing floor assembly 111 has a height difference between its top surface and the top surface of the rear casting body 100, a height difference between its top surface and the top surface of the left rear longitudinal beam assembly 110, and a height difference between its top surface and the top surface of the right rear longitudinal beam assembly 112, forming a spare tire recess on the rear section 11 of the assembly. This height difference is achieved through the design of the cross-sectional height of the longitudinal beam body and the rear casting body 100, with the top surface of the longitudinal beam body higher than the top surface of the rear load-bearing floor assembly 111, thus creating a recessed area visually and structurally. The rear load-bearing floor assembly 111 is typically made of stamped steel sheet metal, with a flanged structure around its perimeter. It is fixed to the surrounding aluminum longitudinal beams and the mounting lugs of the rear casting body 100 via a connecting structure 6, ensuring the stability of the recess structure and preventing vibration and abnormal noise during vehicle operation. The rear floor spare tire pit can fully accommodate three rows of seats, ensuring that after the three rows of seats are folded down, the exposed surface of the three rows of seats and the carpet surface where carpet 5 is placed are on the same plane, forming a large flat space at the rear of the passenger compartment, avoiding the risk of protrusions scratching luggage or people tripping.

[0042] Furthermore, the rear floor spare tire pit is used to accommodate the flip-up seat 4; the depth H of the rear floor spare tire pit is greater than or equal to a first set threshold, and the closed thickness of the flip-up seat 4 is less than the first set threshold; the opening width L of the rear floor spare tire pit is greater than or equal to a second set threshold, and the width of the flip-up seat 4 is less than the second set threshold; the length of the rear floor spare tire pit is greater than or equal to a third set threshold, and the backrest length of the flip-up seat 4 is less than the third set threshold. Specifically, the spare tire pit must have a depth (H) of at least 200mm, a width (X) of at least 645mm, and a length (Y) of at least 1275mm to ensure that the width of the three-seater seats is at least 1200mm. The spare tire pit on the rear floor must be able to fully accommodate all three rows of seats. The first, second, and third threshold values ​​are minimum accommodating space values ​​determined based on the specific vehicle model's seat dimensions. This ensures that the seats can be fully submerged in the pit without protruding when folded or flipped. The depth must accommodate the overall thickness of the seat when closed, the width must accommodate the maximum lateral dimension of the seat when unfolded or folded, and the length must accommodate the folded volume of the seat back and seat cushion. This dimensional matching ensures the feasibility of seat storage and prevents the seats from protruding above the floor after being folded, thus affecting the luggage compartment layout. Furthermore, the opening width of the left and right longitudinal beams of the spare tire pit on the rear floor must be greater than the seat width to ensure that the seats can be smoothly placed into the pit.

[0043] If an integrated die-casting process is used to manufacture the rear floor with a deep pit structure, the depth of the spare tire pit requires a complex core-pulling mechanism in the mold design. Furthermore, the aluminum molten metal is prone to flow problems when filling the deep cavity, making integrated molding difficult and demanding in terms of manufacturing technology. The rear floor assembly in this invention significantly reduces the manufacturing difficulty of components such as the rear casting body 100, creating conditions for accommodating three rows of seats in the pit. By separating the deep pit area from the rear casting body 100 and forming it with the rear load-bearing floor assembly 111 of the rear section 11 of the assembly and the longitudinal beams, shrinkage defects caused by uneven wall thickness in large die-cast parts are avoided. This simplifies the die-casting mold structure, improves production yield, and removes the limitations of the die-casting process on the deep pit size design, thus accommodating larger seat structures and meeting the space requirements for fully folded three rows of seats.

[0044] Furthermore, a top support is provided on the top surface of the rear load-bearing floor assembly 111, the top of which is used to support the flip-up seat 4. Specifically, the top support can be a stamped boss structure or a support bracket welded to the rear load-bearing floor assembly 111. Its height is calculated to ensure that after the flip-up seat 4 is flipped into the recess, the bottom of the seat frame contacts the top of the top support, rather than pressing directly onto the rear load-bearing floor assembly 111. This disperses the weight load of the seat, preventing the rear load-bearing floor assembly 111 from undergoing plastic deformation due to long-term stress, and reducing abnormal noises caused by vibration between the seat and the floor during vehicle operation. The top of the top support can also be covered with a rubber pad to increase friction and cushion impact, ensuring the stability of the flip-up seat 4 in its stowed state. When combined with the carpet 5, the exposed surface of the seat remains flush with the surrounding floor surface, not affecting the flatness of the trunk space. Furthermore, the top support is positioned to avoid the drainage structure 7, preventing corrosion of the connection points due to water accumulation.

[0045] The front section 10 of the assembly also includes: a rear section assembly structure 102 of the sill inner panel, a rear floor connecting plate 103, a front connecting plate assembly 104 of the rear longitudinal beam, a middle panel assembly 105 of the rear floor, and a front connecting plate assembly 106 of the rear floor. These components mainly serve as transitional connectors 61 between the aluminum rear casting body 100 and other steel structures of the vehicle body, and are typically made of steel sheet metal. The rear section assembly structure 102 of the sill inner panel is connected to the rear casting body 100; the rear floor connecting plate 103 is connected to the rear casting body 100; the front connecting plate assembly 104 of the rear longitudinal beam is connected to the rear casting body 100; the middle panel assembly 105 of the rear floor is connected to the rear casting body 105; and the front connecting plate assembly 106 of the rear floor is connected to the rear casting body 106. Through this multi-point connection method, the rear casting body 100 is stably integrated into the body frame. These transition parts ensure that the connection interfaces between the rear casting body 100 and the front and side panels of the body are all steel-to-steel connections, which are compatible with traditional steel body production lines. No additional aluminum connection equipment is required, reducing the need for modification of existing production lines or investment in new production lines. At the same time, structural adhesive 60 and drainage structure 7 are used at the steel-aluminum overlap to effectively block the electrochemical corrosion path and ensure the service life of the hybrid material body.

[0046] The rear section assembly 102 of the inner sill plate, the rear floor connecting plate 103, and the front connecting plate assembly 104 of the rear longitudinal beam are located on both sides of the rear casting body 100 along the left-right direction of the vehicle body; the middle panel assembly 105 of the rear floor and the front connecting plate assembly 106 of the rear floor are respectively located on both sides of the rear casting body 100 along the front-rear direction of the vehicle body. This layout achieves all-round enclosure and support for the rear casting body 100. The left and right side components are mainly responsible for connecting with the side sills and the front section of the longitudinal beam, while the front-rear components are responsible for the transition with the front and middle areas of the floor, ensuring the continuity of the force transmission path. The steel sheet metal parts surround the aluminum parts, which not only serve as structural connections but also protect the internal aluminum structure. A sealing process is used in the steel-aluminum overlap area to prevent corrosion caused by potential differences, while maintaining the flatness of the vehicle body bottom. This provides a foundation for the installation of the interior carpet 5, allowing the carpet 5 to continuously cover the spare tire well and surrounding structural surfaces, avoiding the risk of protrusions scratching luggage or causing people to trip.

[0047] The rear section assembly structure 102 of the sill inner panel includes a left sill inner panel rear section assembly 1021 and a right sill inner panel rear section assembly 1022, which are respectively disposed on both sides of the rear casting body 100 along the left-right direction of the vehicle body. Both parts are steel sheet metal parts, serving as the transition connection structure 6 between the rear casting body 100 and the lower side beam of the vehicle body side panel. They are fixed to the flange edge extending laterally from the rear casting body 100 by welding, forming a steel-aluminum hybrid connection interface. The symmetrical distribution pattern helps to balance the rigidity of both sides of the vehicle body, ensuring that the side collision load can be smoothly transferred from the side panel to the rear floor assembly 1. Structural adhesive 60 is filled at the steel-aluminum overlap interface to isolate air and prevent electrochemical corrosion. At the same time, the outer side connects with the wheel arch inner panel, together forming a closed cavity structure to protect the internal aluminum parts from external stone impact damage.

[0048] The rear floor connecting plate 103 includes: a rear floor left front connecting plate 1031, a rear floor left center connecting plate 1032, a rear floor left rear connecting plate 1033, a rear floor right rear connecting plate 1034, a rear floor right center connecting plate 1035, and a rear floor right front connecting plate 1036. The rear floor left front connecting plate 1031, rear floor left center connecting plate 1032, and rear floor left rear connecting plate 1033 are located on one side of the rear casting body 100 along the left-right direction of the vehicle body, while the rear floor right rear connecting plate 1034, rear floor right center connecting plate 1035, and rear floor right front connecting plate 1036 are located on the other side of the rear casting body 100 along the left-right direction of the vehicle body. This component design, arranged sequentially along the front-rear direction of the vehicle body, can adapt to the complex contour of the front edge of the rear casting body 100, achieving multi-point distributed connection and improving connection reliability. The front ends of each connecting plate are respectively connected to the steel extension of the front floor assembly of the vehicle body to form a steel-to-steel welded interface. This allows the rear floor assembly 1 to be connected to the traditional steel body production line without changing the welding equipment, reducing manufacturing costs. At the same time, the surface of the connecting plate is treated with electrophoresis and forms a closed cavity with the rear casting body 100. Furthermore, these steel connecting parts 61 surround the aluminum load-bearing components, playing a role in protecting the internal core structure and maintaining the flatness of the bottom of the vehicle body.

[0049] The rear longitudinal beam front connecting plate assembly 104 includes a left rear longitudinal beam front connecting plate 1041 and a right rear longitudinal beam front connecting plate 1042, which are respectively disposed on both sides of the rear casting body 100 along the left-right direction of the vehicle body. They are mainly used to connect the rear casting body 100 with the front longitudinal beam structure to ensure that the continuous transmission path of longitudinal collision force is not interrupted. The connecting plates are fastened to the rear casting body 100 by pre-embedded nuts or self-piercing rivets, and are surrounded by a sealing layer, which not only ensures the connection strength but also isolates the steel and aluminum from direct contact. It is used in conjunction with the drainage structure 7 to avoid crevice corrosion caused by water accumulation, ensuring the durability of the vehicle body bottom structure under complex working conditions. In addition, all steel connecting parts 61 are surrounded by aluminum load-bearing parts to protect the internal core structure.

[0050] In this application, the rear load-bearing floor assembly 111 is made of steel sheet metal. The rear section assembly structure 102 of the inner sill plate, the rear floor connecting plate 103, the rear longitudinal beam front connecting plate assembly 104, and the rear floor front connecting plate assembly 106 are also made of steel sheet metal. These components, serving as transitional connectors 61 between the rear floor assembly 1 and other body structures, utilize steel materials, leveraging their mature stamping and welding processes to achieve a matching relationship with the steel structure of the main body. The steel sheet metal components surround the aluminum rear casting body 100 and the aluminum extruded profile longitudinal beams, not only providing structural connection but also forming physical protection for the internal aluminum components, preventing damage to the aluminum surface from external stone impacts. Simultaneously, structural adhesive 60 is used to seal the steel-aluminum interface, effectively isolating direct contact between different metals. This structural design reduces the risk of electrochemical corrosion and ensures the durability of the vehicle's underbody structure in humid environments.

[0051] Specifically, the rear floor assembly 1 connects to the left rear longitudinal beam connecting plate 1103, the left rear longitudinal beam front connecting plate 1041, the rear floor left rear connecting plate 1033, the left sill inner panel rear section assembly 1021, the rear floor left front connecting plate 1031, and the left sill inner panel rear section assembly 1021; it also connects to the right rear longitudinal beam connecting plate, the right rear longitudinal beam front connecting plate 1042, the rear floor left rear connecting plate 1033, the rear floor left center connecting plate 1032, the rear floor left front connecting plate 1031, the left sill inner panel rear section assembly 1021, the rear load-bearing floor assembly 111, and the rear floor front connecting plate assembly 106. All these connecting parts 61 are steel sheet metal components. Through the symmetrically distributed steel connecting plates, the rear floor assembly 1 achieves a stable connection with the front and side structures of the vehicle body. Each connecting plate is positioned with the corresponding structural components of the vehicle body through pre-drilled mounting holes or overlapping edges, ensuring the continuity of the force transmission path. Therefore, the lower lines connecting the rear floor assembly 1 to the front floor assembly and the rear bulkhead assembly 2 are all steel sheet metal to steel sheet metal connections; the connections between the rear floor assembly 1 and the left and right side bulkhead assemblies on the main assembly line are also all steel sheet metal to steel sheet metal connections, no different from traditional steel body connections, and can completely utilize traditional steel body production lines and equipment. This means that during the body-in-white welding process, the existing spot welding robot program, fixture positioning reference, and conveyor rollers do not need to be extensively modified due to the introduction of the aluminum rear floor. The steel connecting plate is directly fixed to the overlapping edge of the front floor and side bulkhead by resistance spot welding, and the welding current and pressure parameters are consistent with those of traditional all-steel bodies, significantly reducing the equipment investment cost and production line modification cycle for the introduction of new models. At the same time, the sealing process of the steel-to-steel connection interface also adopts the mature glue application process, ensuring the overall sealing performance and structural strength of the body, achieving seamless compatibility of the aluminum rear floor assembly 1 on the traditional steel body production line, and improving production efficiency and manufacturing economy.

[0052] To ensure corrosion resistance and sealing at the steel-aluminum joint, continuous structural adhesive 60 is applied at the steel-aluminum overlap. Since drainage is impossible in these areas, this invention utilizes the component-specific characteristics of the steel sheet metal parts to design a drainage structure 7. This drainage structure 7 is located at the lowest point of the overlap flange edge of the steel sheet metal parts surrounding the aluminum component. Because the structural adhesive 60 needs to be continuously applied to ensure connection strength and sealing, this can lead to a closed cavity in the overlap area, causing electrophoresis solution and pretreatment solution to accumulate. Therefore, by utilizing the component-specific characteristics of the steel sheet metal parts, a gap is reserved at the lowest point of the overlap flange edge as a drainage channel, allowing the liquid to flow out naturally by gravity, preventing liquid accumulation that could lead to subsequent corrosion or affect coating quality. Simultaneously, the location of this drainage structure 7 avoids the main stress area of ​​the structural adhesive 60, ensuring that the connection rigidity is not affected.

[0053] Based on the above embodiments, in this embodiment, drainage structures 7 are provided between the rear casting body 100 and the rear load-bearing floor assembly 111, and between the rear casting body 100 and the vehicle side panel structure. The vehicle side panel structure includes the left wheel arch D-pillar inner panel 8 and the left wheel arch C-pillar inner panel 9. That is, drainage structures 7 are provided between the rear casting body 100 and the left wheel arch D-pillar inner panel 8, and between the rear casting body 100 and the left wheel arch C-pillar inner panel 9. These locations are areas prone to water accumulation at the bottom of the vehicle body. By providing drainage structures 7 at the overlap edges of the rear casting body 100 and the rear load-bearing floor assembly 111, and at the connections between the rear casting body 100 and the left wheel arch D-pillar inner panel 8 and the left wheel arch C-pillar inner panel 9, the main steel-aluminum connection interfaces can be covered. As key support components of the vehicle body side panel, the inner D-pillar panel 8 and the inner C-pillar panel 9 of the left wheel arch typically have complex curved transitions at their connection with the rear casting body 100. The design of the drainage structure 7 needs to adapt to these geometries to ensure effective drainage in any posture.

[0054] Drainage structure 7 location as follows Figure 12 As shown, details C, D, and E are symmetrical, with only the left side labeled. Drainage and joint adhesive are illustrated in details B, C, D, E, F, G, and sections A1-A1, A2-A2, A3-A3, BB, and CC. Sections A1-A1, A2-A2, A3-A3, BB, and CC utilize the matching gap at the steel-aluminum connection point for drainage; detail D utilizes the boundary gap between the steel and aluminum sheet metal parts for drainage. This drainage structure 7 solves the problem of draining electrophoretic fluid during welding and electrophoresis of the body-in-white and the draining liquid during pretreatment cleaning, while also providing favorable conditions for absorbing the cumulative tolerances of the steel-aluminum parts in the factory. The matching gap refers to the gap naturally formed by tolerances when steel and aluminum parts overlap, and the boundary gap refers to the pre-reserved gap at the edge break of the sheet metal part. Neither of these methods requires additional openings, avoiding damage to the die-cast part's structure or the connecting adhesive layer. Simultaneously, the existence of gaps allows for certain dimensional deviations in parts during manufacturing and assembly, reducing assembly stress through tolerance absorption and improving the dimensional accuracy of the body.

[0055] In the painting workshop, these drainage structures are designed with seven points of sealant coating to ensure that the edges of the steel and aluminum parts at the drainage channels do not directly contact the air, thus blocking the electrochemical corrosion path. This solves the problem of water accumulation and corrosion in the steel-aluminum gaps and avoids damage to the integrity of the die-cast parts or the bonding adhesive layer due to subsequent drilling. At the same time, the insulation design solves the corrosion risk of the drainage structure itself and does not affect the compatibility of the traditional steel body production line (because the steel sheet metal parts can be pre-treated on the assembly line). The sealant coating forms a protective layer on the outside of the drainage channels, so that the inside of the drainage gaps no longer comes into contact with air and moisture after electrophoresis, thereby preventing electrochemical corrosion caused by the contact of dissimilar metals such as steel and aluminum. This design eliminates the need for secondary drilling for drainage after die casting, protecting the structural integrity and sealing of the rear casting body 100. Moreover, the steel sheet metal parts can be pre-treated for corrosion protection, allowing the entire rear floor assembly 1 to be directly welded and painted on the traditional steel body production line without the need for additional special equipment, achieving a balance between corrosion protection performance and production compatibility.

[0056] It should also be noted that the inner D-pillar panel 8 and the inner C-pillar panel 9 of the left wheel arch are steel structures. These two components, as important parts of the vehicle's side panels, are made of steel to allow for welding connections with other steel parts of the front and side panels, forming a continuous steel body frame. When the steel inner D-pillar panel 8 and the inner C-pillar panel 9 of the left wheel arch overlap with the aluminum rear casting body 100, they form a steel-aluminum hybrid connection interface, requiring specific anti-corrosion processes to ensure durability. Furthermore, their positions are adjacent to the lateral connection area of ​​the rear floor assembly 1, together forming the wheel arch cavity to protect the internal structure from external stone impact damage.

[0057] Furthermore, the rear casting body 100 is connected to the rear load-bearing floor assembly 111, and the rear casting body 100 is connected to the vehicle body side panel structure via a connecting structure 6. The connection interface is typically located on the overlapping flange extending from the edge of the component. The rear casting body 100, as the core load-bearing component, is securely connected to the surrounding steel components via the connecting structure 6. The connecting structure 6 is responsible for transmitting the load during vehicle operation and adapting to dimensional changes caused by the difference in thermal expansion coefficients between steel and aluminum, ensuring the stability of the connection interface under dynamic operating conditions, preventing structural cracking due to stress concentration, and providing a basic interface for subsequent anti-corrosion and sealing treatment.

[0058] The connection structure 6 includes structural adhesive 60 and connector 61. The rear casting body 100 and the rear load-bearing floor assembly 111, as well as the rear casting body 100 and the vehicle side panel structure, are bonded and fixed together by structural adhesive 60. The structural adhesive 60 is continuously applied along the overlapping area, filling the microscopic gaps between the steel and aluminum parts to form a uniform stress transfer layer, while also acting as an insulating medium to block electrochemical corrosion paths. The rear casting body 100 and the rear load-bearing floor assembly 111 are also fixed together by connector 61. Connector 61 passes through pre-drilled mounting holes, pressing the rear load-bearing floor assembly 111 against the flange surface of the rear casting body 100, providing mechanical locking force to assist the structural adhesive 60 in curing and positioning, and providing additional safety redundancy throughout the vehicle's lifespan. Connector 61 typically has an insulating gasket at its head to further isolate the steel and aluminum contact, meeting the requirements for vehicle body rigidity and sealing.

[0059] Secondly, this application provides a rear vehicle body assembly, comprising: a rear floor assembly 1, a rear bulkhead assembly 2, and a rear anti-collision beam assembly 3, as provided in any of the above embodiments of this application. The rear bulkhead assembly 2 is fixed to the rear floor assembly 1 via a detachable connection structure; the rear anti-collision beam assembly 3 is fixed to the rear bulkhead assembly 2 via a detachable connection structure. The rear vehicle body assembly constitutes the main frame of the vehicle's rear end. The rear floor assembly 1 is located at the bottom and bears the load. The rear bulkhead assembly 2 is vertically arranged at the rear end of the rear floor assembly 1, forming the rear wall of the luggage compartment. The rear anti-collision beam assembly 3 is installed at the very end to absorb collision energy. The detachable connection structure specifically includes bolt connection components, which are fastened through preset mounting holes, forming modular interfaces between the assemblies. This facilitates independent disassembly in maintenance scenarios, avoiding the drawbacks of traditional welded vehicle bodies requiring overall cutting and replacement. Simultaneously, structural adhesive 60 is used to seal the connection interface, ensuring the airtightness and watertightness of the vehicle body.

[0060] This application divides the rear floor assembly 1 into two sections, plus the rear bumper beam assembly 3, for a total of three sections, all connected by bolts. Through structural optimization, the damaged areas differ depending on the speed of the rear impact. Different structural sections can be replaced based on the location of the damage, reducing maintenance costs. The rear floor assembly 1 is divided into a front section 10 and a rear section 11. The front section 10 includes the rear casting body 100, and the rear section 11 includes the left rear longitudinal beam assembly 110 and the right rear longitudinal beam assembly 112. These two sections are connected by bolts. Similarly, the rear bumper beam assembly 3 and the rear bulkhead assembly 2 are also connected by bolts, thus forming a three-tiered energy-absorbing unit in the longitudinal direction. This segmented design allows collision energy to be transmitted along a predetermined path. Collisions of different intensities trigger crumpling or deformation in different sections, preventing energy from being directly transferred to the front of the vehicle and causing further damage, providing a physical basis for graded repair.

[0061] For low-speed rear-end collisions, simply replace the rear bumper; for medium-speed rear-end collisions, replace the rear longitudinal beam and subsequent sections of the rear casting; for high-speed rear-end collisions, replace the rear casting and subsequent sections. The rear body assembly mainly consists of an aluminum rear casting body 100, specifically composed of a die-cast rear floor assembly 1, a rear bulkhead assembly 2, and a rear bumper beam assembly 3. Based on the severity of collision damage, this invention divides the rear floor assembly 1 into two sections, which, combined with the rear bumper beam assembly 3, form a three-section collision energy-absorbing structure. Figure 1 , Figure 2 As shown. The three-section energy-absorbing structure is mainly connected by bolts. In a low-speed rear collision, the rear bumper beam assembly 3 is usually damaged. Repair can be done by simply disassembling and replacing the rear bumper beam; the main body of the white body is not affected. In a medium-speed rear collision, the damaged part is the area covered by the rear longitudinal beam assemblies (left rear longitudinal beam assembly 110, right rear longitudinal beam assembly 112) on the rear floor assembly 1, such as... Figure 2 As shown, during maintenance, only the left rear longitudinal beam assembly 110, the right rear longitudinal beam assembly 112, and the rear load-bearing floor assembly 111 need to be replaced. The left and right rear longitudinal beam assemblies 110 and 112 are bolted to the rear casting body 100 and can be directly disassembled and replaced. The rear load-bearing floor assembly 111 is made of sheet metal and can be cut and welded for repair. This design reduces vehicle maintenance costs and will not damage the rear casting body 100 in low-to-medium speed rear-end collisions. In high-speed collisions, the collision energy exceeds the energy absorption limit of the longitudinal beams and affects the rear casting body 100. At this time, it is necessary to replace the front section 10 and all subsequent components of the assembly. However, since the rear casting body 100 is still connected to the front of the vehicle body by a steel connecting plate, the repair interface is clear, avoiding the situation where the entire body-in-white is scrapped due to local damage, significantly improving the economy and maintainability of the vehicle throughout its entire life cycle.

[0062] Based on the above embodiments, in this embodiment, the rear floor assembly 1 includes a front section 10 and a rear section 11; the front section 10 includes a rear casting body 100, and the rear section 11 includes a rear load-bearing floor assembly 111, a separately arranged left rear longitudinal beam assembly 110, and a right rear longitudinal beam assembly 112; the rear casting body 100, the left rear longitudinal beam assembly 110, the right rear longitudinal beam assembly 112, and the rear bulkhead assembly 2 form an enclosure structure, and the rear load-bearing floor assembly 111 is disposed between the rear casting body 100, the left rear longitudinal beam assembly 110, the right rear longitudinal beam assembly 112, and the rear bulkhead assembly 2. This enclosure structure is defined by the rear casting body 100 and the rear bulkhead assembly 2 in the longitudinal direction of the vehicle body, and by the left rear longitudinal beam assembly 110 and the right rear longitudinal beam assembly 112 in the lateral direction of the vehicle body, thereby forming a sunken space in the middle area. The rear load-bearing floor assembly 111 serves as the bottom cover of the sunken space. Its edges overlap with the surrounding structural components to form a complete rear floor spare tire pit structure, providing basic space for subsequent seat storage. The structural components are fixed together by the connecting structure 6 to ensure the overall rigidity and sealing of the vehicle bottom.

[0063] In this application, the aluminum components of the rear floor assembly 11 are divided into two sections: the main body structure is made of cast aluminum, and the longitudinal beams are made of extruded aluminum profiles. The front and rear sections are connected by bolts. This reduces the cost of repairing the main body casting, and the use of extruded aluminum profile longitudinal beams also reduces parts cost and the molding difficulty of the main casting. It also creates conditions for the three rows of seats to fold into the recess. Cast aluminum is suitable for the complex shape and high rigidity required of the rear casting body 100, while extruded aluminum profiles are suitable for the longitudinal beam structure with a constant cross-section that requires frequent replacement. The bolt connection, as a specific implementation of the detachable connection structure, allows the rear section 11 of the assembly to be removed independently of the front section 10 when damaged, avoiding the scrapping of the entire die-cast part due to localized collisions. Furthermore, the segmented design ensures that the recess depth of the rear load-bearing floor assembly 111 is not limited by the molding limit of a single die-cast part, meeting the depth dimensions required for seat storage and solving the problems of high cost and low yield of large deep-cavity die-casting molds.

[0064] The layout of the steel and aluminum parts in the rear floor assembly 1 of this application is as follows: Figure 5 As shown, the main load-bearing areas of the rear floor assembly 1 are designed with aluminum components with strong energy absorption capacity (left rear longitudinal beam assembly 110, right rear longitudinal beam assembly 112, rear casting body 100, and rear floor central reinforcing beam 101). Other non-critical load-bearing areas use steel sheet metal components. This improves performance while reducing component weight, achieving vehicle lightweighting. The steel sheet metal components are mainly distributed around the aluminum components and at the connection interfaces, including the rear floor connecting plate 103 and the rear section assembly structure of the sill inner panel 102. This layout ensures high strength and energy absorption efficiency along the collision force transmission path, and also achieves compatibility with steel-to-steel connections in traditional steel body production lines through the outer steel components. This reduces the corrosion challenges and production line modification costs associated with connecting dissimilar materials. Furthermore, the structure of steel components surrounding aluminum components effectively protects the internal aluminum material from external stone impact damage.

[0065] This application provides a vehicle model with three rows of seats that can be placed in the spare tire well. After the third row of seats are folded down and placed in the well, a large flat space is created in the rear of the car for children to play in, while also increasing the trunk space and storage capacity. Combined with the second row of seats folding down, a bed can be created with a single touch, empowering the multi-functional passenger cabin for various scenarios. The prerequisite for placing the seats in the spare tire well is that the depth of the spare tire well is greater than the thickness of the seat when closed, and the opening width is greater than the width of the seat. This application uses a segmented design for the rear floor assembly 111, which allows the rear load-bearing floor assembly 111 to be set in a lower position without increasing the molding difficulty of the rear casting body 100. After the seats are folded down, their exposed surfaces are flush with the top surface of the rear load-bearing floor assembly 111, thus forming a continuous flat surface, maximizing the use of the vertical space in the vehicle, improving the flexibility and comfort of the user, and the carpet 5 can be continuously laid on this flat surface, further optimizing the interior aesthetics.

[0066] In this application, the aluminum parts of the rear floor assembly 1 are all surrounded by steel sheet metal parts. The connection between the rear floor assembly 1 and other parts assemblies of the body-in-white (left and right side panel assemblies, rear panel assembly, front floor assembly, sill assembly, etc.) is also made of steel sheet metal parts. Specifically, the rear casting body 100, the left rear longitudinal beam assembly 110, and the right rear longitudinal beam assembly 112 are the main aluminum load-bearing components. They are surrounded by steel sheet metal parts such as the rear section assembly structure of the sill inner panel 102, the rear floor connecting plate 103, and the front connecting plate assembly of the rear longitudinal beam 104. These steel sheet metal parts surround the aluminum parts, which not only serve as structural connections but also protect the internal aluminum structure and prevent external gravel from impacting and damaging the aluminum surface. During the manufacturing process, steel-aluminum connections are limited to the rear floor assembly 1. Steel-aluminum connection equipment (FDS / SPR / bolted connections, etc.) only needs to be deployed on the rear floor assembly 1 production line. The connection methods on the lower and final assembly lines are consistent with traditional steel sheet metal bodies. This part of the production line can be shared with traditional steel bodies, reducing the need for modifications to existing production lines or the investment in new production lines, and increasing the compatibility of the body-in-white production line. This is because the steel connecting plate is directly fixed to the overlap edges of the front floor and side panels of the body through resistance spot welding. The welding current and pressure parameters are consistent with those of traditional all-steel bodies, eliminating the need for large-scale modifications due to the introduction of an aluminum rear floor. This achieves seamless compatibility of the aluminum rear floor assembly 1 with the traditional steel body production line, improving production efficiency and manufacturing economy.

[0067] To ensure corrosion resistance and sealing at the steel-aluminum joints, continuous structural adhesive 60 is applied at the overlap points. Since drainage is impossible in these areas, this application utilizes the component characteristics of the sheet metal parts at these steel-aluminum joint locations to design a drainage structure 7. This drainage structure 7 is designed at the lowest point of the overlap flange edge of the steel sheet metal adapter surrounding the aluminum part. The drainage structure 7 utilizes the matching gap at the steel-aluminum joint or the boundary gap between the steel and aluminum sheet metal parts to guide the flow, preventing the accumulation of electrophoretic liquid and rainwater. This avoids liquid buildup that could lead to subsequent corrosion or affect coating quality. Simultaneously, the location of the drainage structure 7 avoids the main stress area of ​​the structural adhesive 60, ensuring that the connection rigidity is not affected. These joint structures also provide favorable conditions for absorbing the cumulative tolerances of the steel-aluminum parts in the factory. In the painting workshop, sealant is applied to these drainage structures 7 to ensure that the edges of the steel and aluminum parts at the drainage channels do not directly contact the air, blocking the electrochemical corrosion path. This design not only solves the problem of water accumulation and corrosion in the gaps between steel and aluminum, but also avoids damage to the integrity of the die-cast parts or the connecting adhesive layer due to subsequent drilling. At the same time, the insulation design solves the corrosion risk of the drainage structure 7 itself. The insulation design is usually achieved by setting an insulating gasket at the connector 61 or applying an insulating adhesive layer to the overlapping surface, which prevents the potential difference generated by direct contact between dissimilar metals and ensures the durability of the vehicle body bottom structure in humid environments.

[0068] This application features a high degree of integration in the rear casting, reducing the number of parts in the rear floor assembly 1, increasing the application ratio of lightweight aluminum components, and lowering the overall weight of the rear floor assembly 1, which is beneficial for vehicle weight reduction. The rear casting body 100 integrates multiple stamped and welded parts into a single part through an integrated die-casting process, reducing welding processes and the number of connecting parts 61. Furthermore, the structure where the aluminum components of the rear floor assembly 1 are surrounded by steel sheet metal effectively protects the internal aluminum materials from external stone impact damage. Simultaneously, the main stress-bearing areas utilize aluminum structures with cross-sections, while other non-main stress-bearing areas use steel sheet metal. This maximizes weight reduction of the rear floor assembly 1 while improving performance, achieving optimal vehicle structure efficiency. Moreover, aluminum components have a lower density than steel; by replacing steel with aluminum to reduce the weight of the rear floor assembly 1 while meeting the same strength requirements, the weight reduction effect is enhanced, thereby reducing overall vehicle energy consumption and allowing users to obtain maximum storage capacity when the third-row seats are not in use.

[0069] Thirdly, embodiments of this application provide a vehicle, which includes: the rear vehicle body assembly provided in any of the above embodiments of this application.

[0070] This application achieves a modular distribution of the rear floor structure by dividing the rear floor assembly 1 into a front section 10 and a rear section 11, and employing a detachable connection structure between the two and between the longitudinal beam and the rear casting body 100. In the event of a rear-end collision, the damage is typically concentrated in the rear area of ​​the vehicle. Because the rear section 11 is detachable from the front section 10, during repairs, only the damaged rear section 11 can be removed from the front section 10 without cutting or replacing the entire rear casting body 100. This allows the rear casting body 100 to be preserved undamaged.

[0071] Meanwhile, the rear section 11 of the assembly employs separate left and right rear longitudinal beam assemblies 110 and 112, further subdividing the rear structure into independent left and right repair units. In the event of an offset collision resulting in damage to one side of the longitudinal beam, the damaged side of the longitudinal beam assembly can be disassembled and replaced individually, while the intact longitudinal beam assembly on the other side can continue to be used. This structural layout reduces the range of parts that need to be replaced during collision repairs and lowers the likelihood of replacing entire structural components due to localized damage, thus providing structural advantages for reducing maintenance complexity.

[0072] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0073] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0074] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A rear floor assembly, characterized in that, It includes: The front section of the assembly (10) includes a rear casting body (100). The rear section (11) of the assembly is detachably connected to the front section (10) of the assembly. The rear section (11) of the assembly includes a left rear longitudinal beam assembly (110) and a right rear longitudinal beam assembly (112) that are separately arranged. The left rear longitudinal beam assembly (110) and the right rear longitudinal beam assembly (112) are fixed to the rear casting body (100) by a detachable connection structure.

2. The rear floor assembly as described in claim 1, characterized in that: The rear section of the assembly (11) also includes a rear load-bearing floor assembly (111). The rear casting body (100), the left rear longitudinal beam assembly (110), and the right rear longitudinal beam assembly (112) are arranged to form a semi-enclosed structure, and the rear load-bearing floor assembly (111) is disposed between the rear casting body (100), the left rear longitudinal beam assembly (110), and the right rear longitudinal beam assembly (112).

3. The rear floor assembly as described in claim 2, characterized in that: There is a height difference between the top surface of the rear bearing floor assembly (111) and the top surface of the rear casting body (100), a height difference between the top surface of the rear bearing floor assembly (111) and the top surface of the left rear longitudinal beam assembly (110), and a height difference between the top surface of the rear bearing floor assembly (111) and the top surface of the right rear longitudinal beam assembly (112), so that a spare tire pit for the rear floor is formed on the rear section (11) of the assembly.

4. The rear floor assembly as described in claim 3, characterized in that: The rear floor spare tire pit is used to accommodate a flip-up seat (4). The depth of the spare tire pit on the rear floor is greater than or equal to the first set threshold, and the closed thickness of the flip-up seat (4) is less than the first set threshold. The opening width of the spare tire pit on the rear floor is greater than or equal to the second set threshold, and the width of the flip-up seat (4) is less than the second set threshold. The length of the spare tire pit in the rear floor is greater than or equal to the third set threshold, and the backrest length of the flip-up seat (4) is less than the third set threshold.

5. The rear floor assembly as described in claim 4, characterized in that: The rear support floor assembly (111) has a top support member on its top surface, and the top of the top support member is used to support the flip-up seat (4).

6. The rear floor assembly as described in claim 2, characterized in that: The rear load-bearing floor assembly (111) is made of steel sheet metal. The rear casting body (100), the left rear longitudinal beam assembly (110), and the right rear longitudinal beam assembly (112) are all made of aluminum.

7. The rear floor assembly as described in claim 2, characterized in that: A drainage structure (7) is provided between the rear casting body (100) and the rear load-bearing floor assembly (111), and between the rear casting body (100) and the vehicle side structure.

8. The rear floor assembly as described in claim 2, characterized in that: The rear casting body (100) and the rear load-bearing floor assembly (111) are connected by a connecting structure (6), and the rear casting body (100) and the vehicle side panel structure are connected by a connecting structure (6).

9. The rear floor assembly as claimed in claim 8, characterized in that: The connection structure (6) includes structural adhesive (60) and connector (61). The rear casting body (100) and the rear load-bearing floor assembly (111) are bonded and fixed together by structural adhesive (60), and the rear casting body (100) and the vehicle side panel structure are bonded and fixed together by structural adhesive (60). The rear casting body (100) and the rear bearing floor assembly (111) are also fixed together by a connector (61).

10. The rear floor assembly as claimed in claim 1, characterized in that: The rear casting body (100) is provided with a rear floor reinforcement beam (101), which is made of aluminum.

11. The rear floor assembly as claimed in claim 1, characterized in that, The front section (10) of the assembly also includes: The rear section assembly structure (102) of the inner sill plate is connected to the rear casting body (100); A rear floor connecting plate (103) is connected to the rear casting body (100); The rear longitudinal beam front connecting plate assembly (104) is connected to the rear casting body (100); The rear floor center panel assembly (105) is connected to the rear casting body (100); The rear floor front connection plate assembly (106) is connected to the rear casting body (100).

12. The rear floor assembly as claimed in claim 11, characterized in that: The rear section assembly structure (102) of the inner sill plate, the rear floor connecting plate (103), and the front connecting plate assembly (104) of the rear longitudinal beam are located on both sides of the rear casting body (100) along the left and right directions of the vehicle body. The rear floor center panel assembly (105) and the rear floor front connecting plate assembly (106) are respectively disposed on both sides of the rear casting body (100) along the front-rear direction of the vehicle body.

13. The rear floor assembly as claimed in claim 11, characterized in that: The rear section assembly structure (102) of the inner door sill includes a left inner door sill rear section assembly (1021) and a right inner door sill rear section assembly (1022), which are respectively disposed on both sides of the rear casting body (100) along the left and right directions of the vehicle body.

14. The rear floor assembly as claimed in claim 11, characterized in that: The rear floor connecting plate (103) includes: rear floor left front connecting plate (1031), rear floor left middle connecting plate (1032), rear floor left rear connecting plate (1033), rear floor right rear connecting plate (1034), rear floor right middle connecting plate (1035) and rear floor right front connecting plate (1036). The rear floor left front connecting plate (1031), rear floor left middle connecting plate (1032), and rear floor left rear connecting plate (1033) are disposed on one side of the rear casting body (100) along the left-right direction of the vehicle body, and the rear floor right rear connecting plate (1034), rear floor right middle connecting plate (1035), and rear floor right front connecting plate (1036) are disposed on the other side of the rear casting body (100) along the left-right direction of the vehicle body.

15. The rear floor assembly as claimed in claim 11, characterized in that: The rear longitudinal beam front connecting plate assembly (104) includes a left rear longitudinal beam front connecting plate (1041) and a right rear longitudinal beam front connecting plate (1042), which are respectively disposed on both sides of the rear casting body (100) along the left and right directions of the vehicle body.

16. The rear floor assembly as claimed in claim 11, characterized in that: The left rear longitudinal beam assembly (110) includes a left rear longitudinal beam body (1101), and a left rear longitudinal beam end plate (1102) and a left rear longitudinal beam connecting plate (1103) are provided on the left rear longitudinal beam body (1101). The right rear longitudinal beam assembly (112) includes a right rear longitudinal beam body, on which a right rear longitudinal beam end plate and a right rear longitudinal beam connecting plate are provided.

17. The rear floor assembly as claimed in claim 16, characterized in that: The rear section assembly of the inner sill plate (102), the rear floor connecting plate (103), the rear longitudinal beam front connecting plate assembly (104), the left rear longitudinal beam connecting plate (1103), the right rear longitudinal beam connecting plate and the rear floor front connecting plate assembly (106) are made of steel sheet metal parts.

18. A rear vehicle body assembly, characterized in that, It includes: The rear floor assembly (1) as described in any one of claims 1-17; The rear panel assembly (2) is fixed to the rear floor assembly (1) by a detachable connection structure. The rear anti-collision beam assembly (3) is fixed to the rear bulkhead assembly (2) by a detachable connection structure.

19. The rear vehicle body assembly as described in claim 18, characterized in that: The rear floor assembly (1) includes a front section (10) and a rear section (11). The front section (10) of the assembly includes a rear casting body (100), and the rear section (11) of the assembly includes a rear load-bearing floor assembly (111), a left rear longitudinal beam assembly (110) and a right rear longitudinal beam assembly (112) that are separately arranged. The rear casting body (100), the left rear longitudinal beam assembly (110), the right rear longitudinal beam assembly (112) and the rear panel assembly (2) are arranged to form an enclosing structure, and the rear load-bearing floor assembly (111) is disposed between the rear casting body (100), the left rear longitudinal beam assembly (110), the right rear longitudinal beam assembly (112) and the rear panel assembly (2).

20. A vehicle, characterized in that, It includes: The rear body assembly as described in any one of claims 18-19.

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