A bottom structure for an electric vehicle body frame

Abstract

This invention discloses a bottom structure for an electric vehicle body frame, comprising: a cabin assembly (1), a front floor assembly (2), and a rear floor assembly (3) arranged sequentially. The front floor assembly (2) includes: a front floor (45), a longitudinal floor central channel cavity (43) forming the center of the floor, two central channel longitudinal beams (25) housed within the floor central channel cavity (43) and symmetrically arranged on both sides of the central axis of the floor central channel cavity (43), a power battery (44) disposed below the floor central channel cavity (43), and two front floor longitudinal beams (24) and two door sill beams (23) symmetrically arranged on both sides of the power battery (44) and arranged sequentially from the inside to the outside. This invention satisfies the space requirements for power battery placement for long range, while also taking into account the collision safety performance and structural continuity of the bottom structure of the vehicle body frame.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, and in particular to a bottom structure for an electric vehicle body frame. Background Technology

[0002] Currently, major automobile manufacturers are following the trend of international technological development and vigorously developing electric vehicles.

[0003] Electric vehicles have gained significant acceptance as a new mode of transportation. Currently, driving range and collision safety are the most pressing concerns for consumers. Driving range is closely related to factors such as vehicle weight, battery capacity, and battery energy management; collision safety, in turn, is related to the rationality of the vehicle's structure and its overall rigidity. Simply increasing battery capacity within existing, mature traditional vehicle body structures inevitably encroaches on the space of the vehicle frame, affecting collision safety reliability. Conversely, compensating for collision problems caused by structural deficiencies requires additional structural reinforcements, which inevitably increases the vehicle's weight and impacts driving range. Therefore, optimizing the vehicle frame structure, reducing overall vehicle weight, and significantly increasing battery capacity within existing technologies, without increasing manufacturing costs, is a core issue for highlighting product competitiveness.

[0004] Existing electric vehicles still use the same bottom structure as traditional, mature gasoline-powered vehicles.

[0005] like Figure 1 As shown, the bottom structure of a traditional, mature gasoline-powered vehicle body frame typically consists of an engine compartment assembly 1', a front floor assembly 2', and a rear floor assembly 3'. Because the bottom structure of the body frame is symmetrical, the following explanation uses a single-side structure as an example. The transverse frame structure of the front floor assembly 2' typically consists of a sill beam 23', a floor longitudinal beam 24', and a center tunnel longitudinal beam 25', forming a six-beam structure on both sides. For example... Figure 1 As indicated by the middle arrow, the force of a frontal collision is transmitted and distributed through the front bumper beam 11', front longitudinal beam 12', sill beam connector 21', and center tunnel longitudinal beam connector 22' of the cabin assembly 1' to the front bulkhead crossbeam 13', the sill beam 23', front floor longitudinal beam 24', and center tunnel longitudinal beam 25' of the front floor assembly 2'; the force of a rear collision is transmitted and distributed through the rear bumper beam 33' and rear longitudinal beam 31' of the rear floor assembly 3' to the rear floor crossbeam 32', the front floor rear crossbeam 26', front floor longitudinal beam 24', and sill beam 23' of the front floor assembly 2'. The entire force transmission structure at the bottom of the vehicle frame is continuous from front to rear, and the passenger compartment area is decomposed into a six-longitudinal beam structure on the left and right sides through structural connectors, which is very beneficial for the integrity protection of the passenger compartment and the distribution of collision force.

[0006] However, reference Figure 2For pure electric vehicles, the power battery 44' needs to be placed below the front floor assembly 2', for example, below the floor center tunnel cavity 43'. Especially for power batteries with long range, while ensuring the ground clearance 41' between the power battery 44' and the ground 42', the space occupied by the power battery inevitably encroaches on the cross-sectional size of the front floor longitudinal beam 24' and the center tunnel longitudinal beam 25' under the front floor assembly 2', both laterally and vertically, significantly impacting the stability and safety of the current vehicle structure. If the cross-section of the structural components is not changed, the space occupied by the power battery will be further reduced, leading to a decrease in battery capacity and affecting the range. Summary of the Invention

[0007] Therefore, it is necessary to address the impact of adding a power battery to the bottom structure of the existing electric vehicle body frame on the stability and safety of the vehicle structure.

[0008] This invention provides a bottom structure for an electric vehicle body frame, comprising: a cabin assembly, a front floor assembly, and a rear floor assembly arranged sequentially. The front floor assembly includes: a front floor, a longitudinal floor channel cavity forming a central channel cavity in the center of the floor, two central channel longitudinal beams housed within the floor channel cavity and symmetrically arranged on both sides of the central axis of the floor channel cavity, a power battery disposed below the floor channel cavity, and two front floor longitudinal beams and two door sill beams symmetrically arranged on both sides of the power battery and arranged sequentially from the inside to the outside.

[0009] This invention meets the space requirements for power battery placement in long-range vehicles, while also taking into account the collision safety performance and structural integrity of the bottom structure of the vehicle frame. Taking advantage of the fact that electric vehicles do not need to occupy the space of the exhaust channel, the traditional six longitudinal beam structure of the front floor of the vehicle body is optimized and, together with the engine compartment assembly and the rear floor assembly, forms a multi-path collision transmission frame structure. The frame structure with performance comparable to that of traditional models is retained, and the manufacturing process and cost are not changed accordingly.

[0010] Furthermore, one side of the front floor longitudinal beam overlaps with the sill beam located on the same side as the channel cavity in the floor, and the other side of the front floor longitudinal beam away from the sill beam overlaps with the front floor.

[0011] In this embodiment, the front floor longitudinal beam and the sill beam are overlapped to form a double longitudinal beam structure, which enhances stability.

[0012] Furthermore, the bottom of one side of the front floor longitudinal beam is provided with a first extension extending toward the sill beam located on the same side as the channel cavity in the floor, and the top of the other side of the front floor longitudinal beam away from the sill beam is provided with a second extension extending toward the front floor. The first extension is connected to the bottom of the sill beam located on the same side as the channel cavity in the floor, and the second extension is connected to the top of the front floor.

[0013] In this embodiment, the front floor longitudinal beam is changed from the original U-shaped structure to an L-shaped structure, which facilitates its connection with the sill beam to form a double longitudinal beam structure.

[0014] Furthermore, the cabin assembly includes: a front bumper beam and two front longitudinal beams symmetrically arranged on both sides of the central passage cavity in the floor. One end of the front longitudinal beam is connected to the end of the front bumper beam, and the other end is connected to the front floor longitudinal beam and the sill beam located on the same side of the central passage cavity in the floor via the rear section of the front longitudinal beam.

[0015] In this embodiment, the rear section of the front longitudinal beam is connected to the front floor longitudinal beam and the sill beam, which serves to strengthen the stability of the transmission structure.

[0016] Furthermore, the rear section of the front longitudinal beam bends and extends outward toward the power battery.

[0017] In this embodiment, the rear section of the front longitudinal beam is bent and extended to facilitate connection with the front floor longitudinal beam that has been moved to the outside of the power battery.

[0018] Furthermore, it also includes sill beam connectors symmetrically arranged on both sides of the channel cavity in the floor, the sill beam connectors overlapping with the rear section of the front longitudinal beam and the sill beam located on the same side of the channel cavity in the floor.

[0019] In this embodiment, the sill beam connector is overlapped with the rear section of the front longitudinal beam and the sill beam structure, which serves to strengthen the stability of the transmission structure.

[0020] Furthermore, it also includes two central channel longitudinal beam connectors symmetrically arranged on both sides of the central axis of the central channel cavity in the floor. The central channel longitudinal beam connectors are respectively connected to the rear section of the front longitudinal beam and the central channel longitudinal beam located on the same side of the central axis of the central channel cavity in the floor.

[0021] In this embodiment, the central channel longitudinal beam is connected to the rear section of the front longitudinal beam and the central channel longitudinal beam through the central channel longitudinal beam connector. Through the above measures, the frame structure of the engine compartment assembly and the front floor assembly overlaps in a manner similar to that of a traditional vehicle body frame structure. The energy of a frontal collision can be dispersed and transferred to the six longitudinal beams on the left and right sides of the floor through the overlapping frame structure, ensuring the stability and safety of the frame structure in the collision without encroaching on the space for the power battery.

[0022] Furthermore, the rear floor assembly includes a rear floor crossbeam and two rear longitudinal beams symmetrically arranged on both sides of the channel cavity in the floor. One end of the rear longitudinal beam is connected to the end of the rear floor crossbeam, and the other end is connected to the front floor longitudinal beam located on the same side of the channel cavity in the floor.

[0023] In this embodiment, the rear longitudinal beam is connected to both the sill beam of the front floor assembly and the front floor longitudinal beam, so that the frame structure of the rear floor assembly and the frame structure of the front floor assembly form a continuous frame structure.

[0024] Furthermore, it also includes rear floor diagonal bracing beams symmetrically arranged on both sides of the channel cavity in the floor, with one end of the rear floor diagonal bracing beam connected to the rear longitudinal beam and the other end connected to the middle of the rear floor transverse beam.

[0025] This embodiment adds a rear floor diagonal brace beam to resist side impacts and strengthen the protection of the power battery by the vehicle frame structure.

[0026] Furthermore, the two central channel longitudinal beams are respectively arranged on both sides of the inner wall of the central channel cavity in the floor.

[0027] In this embodiment, the two central channel longitudinal beams are respectively set on both sides of the inner wall of the central channel cavity in the floor, which facilitates the fixing of the central channel longitudinal beams and the dispersion and transmission of collision energy.

[0028] This invention meets the space requirements for power battery placement in long-range vehicles, while also taking into account the collision safety performance and structural integrity of the bottom structure of the vehicle frame. Taking advantage of the fact that electric vehicles do not need to occupy the space of the exhaust channel, the traditional six longitudinal beam structure of the front floor of the vehicle body is optimized and, together with the engine compartment assembly and the rear floor assembly, forms a multi-path collision transmission frame structure. The frame structure with performance comparable to that of traditional models is retained, and the manufacturing process and cost are not changed accordingly. Attached Figure Description

[0029] Figure 1 This is a structural diagram of the bottom structure of an existing electric vehicle body frame;

[0030] Figure 2 for Figure 1 AA section diagram;

[0031] Figure 3 This is a schematic diagram of the bottom structure of an electric vehicle body frame according to the present invention;

[0032] Figure 4 for Figure 3 BB cross-sectional view. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 3The diagram shows a structural schematic of the bottom structure of an electric vehicle body frame according to the present invention, including: a cabin assembly 1, a front floor assembly 2, and a rear floor assembly 3 arranged sequentially. The front floor assembly 2 includes: a front floor 45, a longitudinal floor channel cavity 43 forming a longitudinal channel cavity 43 in the center of the floor, two central channel longitudinal beams 25 housed in the floor channel cavity 43 and symmetrically arranged on both sides of the central axis of the floor channel cavity 43, a power battery 44 arranged below the floor channel cavity 43, and two front floor longitudinal beams 24 and two door sill beams 23 symmetrically arranged on both sides of the power battery 44 and arranged sequentially from the inside to the outside.

[0035] Specifically, such as Figure 3 and Figure 4 As shown, this invention uses the central axis of the floor central channel cavity 43 as the center line, and symmetrically arranges two central channel longitudinal beams 25, two front floor longitudinal beams 24, and two door sill beams 23 to form a six-longitudinal-beam structure. Taking advantage of the fact that pure electric vehicles do not require an exhaust system, and fully utilizing the structure of the central channel cavity 43, the central channel longitudinal beams 25 are moved to the inside of the central channel cavity 43, placing them above the power battery 44. Simultaneously, the front floor longitudinal beams 24 are moved outward to the outside of the power battery 44. Therefore, while retaining the traditional six-longitudinal-beam structure of the front floor of the vehicle, the ground clearance 41 of the power battery is significantly increased, meeting the space requirements of the power battery.

[0036] This invention meets the space requirements for power battery placement in long-range vehicles, while also taking into account the collision safety performance and structural integrity of the bottom structure of the vehicle frame. Taking advantage of the fact that electric vehicles do not need to occupy the space of the exhaust channel, the traditional six longitudinal beam structure of the front floor of the vehicle body is optimized and, together with the engine compartment assembly and the rear floor assembly, forms a multi-path collision transmission frame structure. The frame structure with performance comparable to that of traditional models is retained, and the manufacturing process and cost are not changed accordingly.

[0037] like Figure 4 As shown, in one embodiment, one side of the front floor longitudinal beam 24 overlaps with the sill beam 23 located on the same side as the channel cavity 43 in the floor, and the other side of the front floor longitudinal beam 24 away from the sill beam 23 overlaps with the front floor 45.

[0038] In this embodiment, the front floor longitudinal beam and the sill beam are overlapped to form a double longitudinal beam structure, which enhances stability.

[0039] In one embodiment, the bottom of one side of the front floor longitudinal beam 24 is provided with a first extension 241 extending toward the sill beam 23 on the same side as the floor channel cavity 43, and the top of the other side of the front floor longitudinal beam 24 away from the sill beam 23 is provided with a second extension 242 extending toward the front floor 45. The first extension 241 is connected to the bottom of the sill beam 23 on the same side as the floor channel cavity 43, and the second extension 242 is connected to the top of the front floor 45.

[0040] In this embodiment, the front floor longitudinal beam is changed from the original U-shaped structure to an L-shaped structure, which facilitates its connection with the sill beam to form a double longitudinal beam structure.

[0041] In one embodiment, the cabin assembly 1 includes: a front bumper beam 11 and two front longitudinal beams 12 symmetrically arranged on both sides of the central passage cavity 43 in the floor. One end of the front longitudinal beam 12 is connected to the end of the front bumper beam 11, and the other end is connected to the front floor longitudinal beam 24 and the sill beam 23 on the same side of the central passage cavity 43 in the floor via the rear section 121 of the front longitudinal beam.

[0042] In this embodiment, the rear section of the front longitudinal beam is connected to the front floor longitudinal beam and the sill beam, which serves to strengthen the stability of the transmission structure.

[0043] In one embodiment, the rear section 121 of the front longitudinal beam bends and extends outward toward the power battery 44.

[0044] In this embodiment, the rear section of the front longitudinal beam is bent and extended to facilitate connection with the front floor longitudinal beam that has been moved to the outside of the power battery.

[0045] In one embodiment, a threshold beam connector 21 is also included, which is symmetrically arranged on both sides of the channel cavity 43 in the floor. The threshold beam connector 21 overlaps with the rear section 121 of the front longitudinal beam and the threshold beam 23 located on the same side of the channel cavity 43 in the floor.

[0046] In this embodiment, the sill beam connector is overlapped with the rear section of the front longitudinal beam and the sill beam structure, which serves to strengthen the stability of the transmission structure.

[0047] In one embodiment, the system further includes two central channel longitudinal beam connectors 22 symmetrically arranged on both sides of the central axis of the central channel cavity 43 in the floor. The central channel longitudinal beam connectors 22 are respectively connected to the rear section 121 of the front longitudinal beam and the central channel longitudinal beam 25, which are located on the same side of the central axis of the central channel cavity 43 in the floor.

[0048] In this embodiment, the central channel longitudinal beam is connected to the rear section of the front longitudinal beam and the central channel longitudinal beam through the central channel longitudinal beam connector. Through the above measures, the frame structure of the engine compartment assembly and the front floor assembly overlaps in a manner similar to that of a traditional vehicle body frame structure. The energy of a frontal collision can be dispersed and transferred to the six longitudinal beams on the left and right sides of the floor through the overlapping frame structure, ensuring the stability and safety of the frame structure in the collision without encroaching on the space for the power battery.

[0049] In one embodiment, the rear floor assembly 3 includes a rear floor crossbeam 32 and two rear longitudinal beams 31 symmetrically arranged on both sides of the channel cavity 43 in the floor. One end of the rear longitudinal beam 31 is connected to the end of the rear floor crossbeam 32, and the other end is connected to the front floor longitudinal beam 24 and the sill beam 23 located on the same side of the channel cavity 43 in the floor.

[0050] In this embodiment, the rear longitudinal beam is connected to both the sill beam of the front floor assembly and the front floor longitudinal beam, so that the frame structure of the rear floor assembly and the frame structure of the front floor assembly form a continuous frame structure.

[0051] In one embodiment, a rear floor bracing beam 34 is also included, which is symmetrically arranged on both sides of the channel cavity 43 in the floor. One end of the rear floor bracing beam 34 is connected to the rear longitudinal beam 31, and the other end is connected to the middle of the rear floor cross beam 32.

[0052] This embodiment adds a rear floor diagonal brace beam to resist side impacts and strengthen the protection of the power battery by the vehicle frame structure.

[0053] In one embodiment, the two central channel longitudinal beams 25 are respectively disposed on both sides of the inner wall of the central channel cavity 43 in the floor.

[0054] In this embodiment, the two central channel longitudinal beams are respectively set on both sides of the inner wall of the central channel cavity in the floor, which facilitates the fixing of the central channel longitudinal beams and the dispersion and transmission of collision energy.

[0055] As a preferred embodiment of the present invention, such as Figure 3 and Figure 4As shown, an electric vehicle body frame bottom structure retains the six longitudinal beams on the left and right sides of the traditional front floor assembly 2 of the vehicle frame, while meeting the space requirements for arranging the power battery 44. Taking advantage of the fact that pure electric vehicles do not need to arrange an exhaust system, the structure of the central channel cavity 43 is fully utilized, and the central channel longitudinal beam 25 is moved to the inside of the central channel cavity 43, so that the central channel longitudinal beam 25 will be located above the power battery 44. In addition, the original U-shaped structure of the front floor longitudinal beam 24 is changed to an L-shaped structure and moved to the outside of the power battery 44, forming a double longitudinal beam structure with the sill beam 23 of the traditional body structure. Specifically, the bottom of one side of the front floor longitudinal beam 24 is provided with a first extension 241 extending toward the sill beam 23 on the same side as the floor channel cavity 43, and the top of the other side of the front floor longitudinal beam 24 away from the sill beam 23 is provided with a second extension 242 extending toward the front floor 45. The first extension 241 is connected to the bottom of the sill beam 23 on the same side as the floor channel cavity 43, and the second extension 242 is connected to the top of the front floor 45.

[0056] To ensure that the front longitudinal beam 12 in the front engine compartment assembly 1 is connected to the front floor longitudinal beam 24 and the middle channel longitudinal beam 25 in the above structure, the rear section 121 of the front longitudinal beam is smoothly bent outward of the power battery 44 and connected to the sill beam 23 and the front floor longitudinal beam 24; at the same time, the sill beam connector 21 is adapted to a reduced structure and overlapped with the rear section 121 of the front longitudinal beam and the sill beam 23 structure to strengthen the stability transmission structure.

[0057] The central channel longitudinal beam connector 22 is connected to the aforementioned front longitudinal beam 12 and central channel longitudinal beam 25. Through the above measures, the frame structure of the engine compartment assembly 1 and the front floor assembly 2 overlaps in a manner similar to that of a traditional vehicle body frame structure. The energy of a frontal collision can be dispersed and transferred to the six longitudinal beams on the left and right sides of the floor through the overlapping frame structure, ensuring the stability and safety of the frame structure in the collision without encroaching on the space for the power battery 44.

[0058] The rear longitudinal beam 31 of the rear floor assembly 3 is connected to the sill beam 23 and the front floor longitudinal beam 24 of the front floor assembly 2, so that the frame structure of the rear floor assembly 3 and the frame structure of the front floor assembly 2 form a continuous frame structure.

[0059] To resist side impacts and enhance the protection of the power battery 44 by the vehicle frame structure, an oblique rear floor brace beam 34 is added between the rear longitudinal beam 31 and the rear floor crossbeam 32 of the traditional vehicle frame bottom structure, forming a triangular frame structure. Together with the sill beam connector 21, the central channel longitudinal beam connector 22, and the front floor rear crossbeam 26, it forms a side impact transmission path frame.

[0060] Among all the above measures, the engine compartment assembly 1, the front floor assembly 2, and the rear floor assembly 3 are connected to form a complete bottom force transmission structure of the body frame. The transmission path is not significantly changed compared with the mature traditional vehicle structure, which ensures the reliability of the structure. Through CAE simulation analysis and real vehicle verification, the crash performance and body rigidity meet the design requirements of traditional vehicles.

[0061] like Figure 3 As indicated by the middle arrow, the force of a frontal collision is transmitted and distributed through the front bumper beam 11, front longitudinal beam 12, rear section of the front longitudinal beam 121, sill beam connector 21, and center channel longitudinal beam connector 22 of the cabin assembly 1 to the front bulkhead crossbeam 13, the sill beam 23, the front floor longitudinal beam 24, and the center channel longitudinal beam 25 of the front floor assembly 2; the force of a rear collision is transmitted and distributed through the rear bumper beam 33 and rear longitudinal beam 31 of the rear floor assembly 3 to the rear floor crossbeam 32, the front floor rear crossbeam 26, the front floor longitudinal beam 24, and the sill beam 23 of the front floor assembly 2.

[0062] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A bottom structure for an electric vehicle body frame, characterized in that, The application relates to a vehicle body structure, which comprises a cabin assembly (1), a front floor assembly (2) and a rear floor assembly (3) arranged in sequence, wherein the front floor assembly (2) comprises a front floor (45), a longitudinal floor passage cavity (43) formed in the center of the floor, two middle passage longitudinal beams (25) symmetrically arranged in the floor passage cavity (43) and on both sides of the middle axis of the floor passage cavity (43), a power battery (44) arranged below the floor passage cavity (43), and two front floor longitudinal beams (24) and two rocker beams (23) symmetrically arranged on both sides of the power battery (44) and arranged in sequence from inside to outside. The cabin assembly (1) comprises a front anti-collision beam (11) and two front longitudinal beams (12) symmetrically arranged on both sides of the floor passage cavity (43), one end of the front longitudinal beam (12) is connected with the end of the front anti-collision beam (11), and the other end is connected with the front floor longitudinal beam (24) and the rocker beam (23) on the same side of the floor passage cavity (43) through a front longitudinal beam rear section (121). One side of the front floor longitudinal beam (24) is overlapped with the rocker beam (23) on the same side of the floor passage cavity (43), and the other side of the front floor longitudinal beam (24) away from the rocker beam (23) is overlapped with the front floor (45). The bottom of one side of the front floor longitudinal beam (24) is provided with a first extension (241) extending to the rocker beam (23) on the same side of the floor passage cavity (43), and the top of the other side of the front floor longitudinal beam (24) away from the rocker beam (23) is provided with a second extension (242) extending to the front floor (45), the first extension (241) is connected with the bottom of the rocker beam (23) on the same side of the floor passage cavity (43), and the second extension (242) is connected with the top of the front floor (45).

2. The electric automobile body frame bottom structure according to claim 1, characterized by, The front longitudinal beam rear section (121) is bent and extended to the outside of the power battery (44).

3. The electric vehicle body frame floor structure according to claim 1, characterized by, The application further comprises rocker beam connectors (21) symmetrically arranged on both sides of the floor passage cavity (43), the rocker beam connector (21) is overlapped with the front longitudinal beam rear section (121) and the rocker beam (23) on the same side of the floor passage cavity (43).

4. The electric vehicle body frame floor structure according to claim 1, characterized by, The application further comprises two middle passage longitudinal beam connectors (22) symmetrically arranged on both sides of the middle axis of the floor passage cavity (43), the middle passage longitudinal beam connector (22) is connected with the front longitudinal beam rear section (121) and the middle passage longitudinal beam (25) on the same side of the middle axis of the floor passage cavity (43) respectively.

5. The electric vehicle body frame floor structure according to claim 1, characterized by, The rear floor assembly (3) comprises a rear floor cross beam (32) and two rear longitudinal beams (31) symmetrically arranged on both sides of the floor passage cavity (43), one end of the rear longitudinal beam (31) is connected with the end of the rear floor cross beam (32), and the other end is connected with the front floor longitudinal beam (24) and the rocker beam (23) on the same side of the floor passage cavity (43).

6. The electric vehicle body frame floor structure according to claim 1, characterized by, ​ 7. The electric vehicle body frame floor structure according to claim 6, characterized by, The rear floor diagonal bracing beam (34) is symmetrically arranged on both sides of the floor mid-passage cavity (43), and one end of the rear floor diagonal bracing beam (34) is connected with the rear longitudinal beam (31), and the other end is connected with the middle part of the rear floor cross beam (32).

8. The electric vehicle body frame floor structure according to any one of claims 1 to 7, characterized by Two mid-passage longitudinal beams (25) are arranged on both sides of the inner wall of the floor mid-passage cavity (43).

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