CN111434562A - Lower vehicle body frame structure - Google Patents

Abstract

The invention provides a lower body frame structure, comprising a left front longitudinal beam, a right front longitudinal beam, a left door sill, a right door sill and a middle channel, and the lower vehicle body frame structure further includes a front wall lower beam, a left front longitudinal beam joint and a right front longitudinal beam a beam joint, the cowl lower cross member is located between the left sill and the right sill, the middle part of the cowl lower cross member is connected with the front end of the middle channel; the left front longitudinal beam joint and the right front longitudinal The opening of the beam joint is upward, the left front longitudinal beam joint is respectively connected with the rear end of the left front longitudinal beam, the front end of the left rocker and the left end of the cowl lower cross member, and the right front longitudinal beam joint is respectively connected with the right front side member. The rear end of the longitudinal beam, the front end of the right rocker, and the right end of the cowl lower cross member are connected. The lower vehicle body frame structure of the present invention can improve crash performance and achieve light weight.

Description

Lower body frame structure

technical field

The invention relates to the field of automobiles, in particular to a lower body frame structure.

Background technique

At present, gasoline-driven transmission vehicles and pure electric vehicles generally have a lower body frame as the skeleton of the whole vehicle. Steering system, cab, cargo box and related operating mechanisms. The lower body frame plays the role of supporting and connecting various parts of the car, and bears various loads from inside and outside the car. Therefore, the lower body frame must have sufficient strength and rigidity to withstand the load of the car and the impact from the wheels.

With the improvement of people's safety awareness and driven by subjective and objective factors such as driving experience and environmental protection requirements, collision safety and lightweight design have become important topics in current body design, and are also an inevitable development trend in the future, especially for pure electric vehicles. Lightweight requirements are higher. Reasonable arrangement of the body frame under the car body is the most effective measure to achieve light weight on the basis of satisfying the crash resistance and stiffness characteristics of the car body.

The front and rear longitudinal beam joints of the existing pure electric vehicle lower body frame generally use torsion joints to improve the transmission path from the cabin longitudinal beam to the door sill, and the front wall root beam adopts a large extruded profile structure to stabilize the support frame. A common technical problem with structures is that lightweighting is not ideal.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a lower body frame structure for the collision performance improvement and weight control requirements of the lower body frame structure of the existing pure electric vehicle.

A lower vehicle body frame structure is provided, comprising a left front side member, a right front side member, a left door sill, a right side sill and a middle channel, the lower vehicle body frame structure further comprising a cowl lower cross member, a left front side member joint and a right front side member joint , the cowl lower cross member is located between the left rocker and the right rocker, the middle part of the cowl lower cross member is connected with the front end of the middle channel; the left front side member joint and the right front side member joint The opening is upward, the left front longitudinal beam joint is respectively connected with the rear end of the left front longitudinal beam, the front end of the left door sill and the left end of the dash lower beam, and the right front longitudinal beam joint is respectively connected with the right front longitudinal beam The rear end of the sill, the front end of the right sill and the right end of the front wall lower cross member are connected.

Further, the left front longitudinal beam joint and the right front longitudinal beam joint are internally provided with a quadrilateral rib-like structure.

Further, a rice-shaped rib-like structure is arranged inside the front wall lower beam.

Further, the left front longitudinal beam joint includes a left front longitudinal beam upper joint and a left front longitudinal beam lower joint, and the left front longitudinal beam upper joint and the left front longitudinal beam lower joint close to the connection end of the left front longitudinal beam rear end are formed by buckling. The beam body is closed; the right front longitudinal beam joint includes a right front longitudinal beam upper joint and a right front longitudinal beam lower joint, and the right front longitudinal beam upper joint and the right front longitudinal beam lower joint are fastened to the connection end of the right front longitudinal beam rear end. form a closed beam.

Further, the upper joint of the left front longitudinal beam and the upper joint of the right front longitudinal beam are provided with a m-shaped rib-like structure, and the lower joint of the left front longitudinal beam and the lower joint of the right front longitudinal beam are provided with a quadrilateral rib-like structure. .

Further, the height of the side wall of the lower joint of the left front longitudinal member at the connection with the left sill is greater than the height of the left sill, and the height of the side wall of the lower joint of the right front longitudinal member at the connection with the right sill is greater than that of the left sill. The height of the right sill.

Further, the lower body frame structure also includes a front wall upper beam, a front seat front beam, a front seat rear beam and a rear seat front beam, and the front wall upper beam is connected to the left front longitudinal beam. Between the upper joint of the beam and the upper joint of the right front longitudinal beam, the front cross beam of the front seat, the rear cross beam of the front seat and the front cross beam of the rear seat are sequentially connected to the left sill and the Between the right door sill, the middle channel is sequentially connected with the front beam of the front seat, the rear beam of the front seat and the middle of the front beam of the rear seat.

Further, the lower body frame structure further includes a left rear longitudinal beam, a right rear longitudinal beam, a rear floor beam, a left rear longitudinal beam joint and a right rear longitudinal beam joint, and the rear floor beam is connected to the left rear longitudinal beam. between the front end of the beam and the front end of the right rear longitudinal beam; the left rear longitudinal beam joint and the right rear longitudinal beam joint have upward openings, and the front ends of the left rear longitudinal beam joint are respectively connected with the rear of the left rocker. and the left end of the front cross member of the rear seat, the rear end of the left rear longitudinal beam joint is respectively connected with the front end of the left rear longitudinal beam and the left end of the rear floor beam; the right rear longitudinal beam The front end of the joint is respectively connected with the rear end of the right rocker and the right end of the front cross member of the rear seat, and the rear end of the right rear side member joint is respectively connected with the front end of the right rear side member and the rear floor The right end of the beam is connected.

Further, the left rear longitudinal beam joint and the right rear longitudinal beam joint are internally provided with cross-shaped tendon structures.

Further, the lower body frame structure further includes a rear wall cross member, and the rear wall cross member is connected between the rear end of the left rear side member and the rear end of the right rear side member.

The beneficial effect brought by the invention is that the left front longitudinal beam joint and the right front longitudinal beam joint resist the bending deformation force and support the front longitudinal beam to absorb energy, stabilize the front wall by the front wall lower beam, and pass the middle channel of the floor, the left door sill and the front wall. The three force transmission paths of the right door sill realize collision safety performance and light weight.

Description of drawings

1 is a schematic structural diagram of a lower body frame structure provided by an embodiment of the present invention;

2 is a schematic structural diagram of a joint on a left front longitudinal beam provided by an embodiment of the present invention;

3 is a schematic structural diagram of a lower joint of a left front longitudinal beam provided by an embodiment of the present invention;

4 is a schematic structural diagram of a left front longitudinal beam joint provided by an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a cowl frame provided by an embodiment of the present invention.

The reference numerals in the accompanying drawings are as follows:

1. Left front longitudinal beam; 2. Right front longitudinal beam; 3. Left door sill; 4. Right door sill; 5. Middle tunnel; 7. Left front longitudinal beam joint; 701. Left front longitudinal beam upper joint; 7011. First bottom plate; 7012. First side plate; 7013. First inner rib; 702. Left front longitudinal beam lower joint; 7021. No. 7022, the second connection end; 7023, the third connection end; 7024, the second bottom plate; 7025, the second side plate; 7026, the second inner rib; 8, the right front longitudinal beam joint; 801, the right front longitudinal beam Upper joint; 8011, the third bottom plate; 8012, the third side plate; 8013, the third inner rib; 802, the lower joint of the right front longitudinal beam; 8021, the fourth connection end; 8022, the fifth connection end; 8023, the sixth connection end; 8024, the fourth bottom plate; 8025, the fourth side plate; 8026, the fourth inner rib; 9, the upper beam of the front wall; 10, the front beam of the front seat; 11, the rear beam of the front seat; 12, the rear Row seat front cross member; 13. Left rear side member; 14. Right rear side member; 15. Rear floor cross member; 16. Left rear side member joint; 1601, Sixth floor panel; 1602, Sixth side panel; 1603, No. Six internal ribs; 17, right rear longitudinal beam joint; 1701, seventh bottom plate; 1702, seventh side plate; 1703, seventh internal ribs; 18, rear surround beam.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

As shown in FIGS. 1-5 , an embodiment of the present invention provides a frame structure of a lower vehicle body, including a left front longitudinal beam 1 , a right front longitudinal beam 2 , a left door sill 3 , a right door sill 4 and a middle channel 5 . The body frame structure also includes a front wall lower cross member 6, a left front side member joint 7 and a right front side member joint 8. The front wall lower cross member 6 is located between the left door sill 3 and the right door sill 4. The middle part of the cross member 6 is connected with the front end of the middle channel 5; , The front end of the left rocker 3 is connected with the left end of the front wall lower cross member 6, and the right front side member joint 8 is respectively connected with the rear end of the right front side member 2, the front end of the right rocker 4 and the front The right end of the lower cross beam 6 is connected.

In the embodiment of the present invention, the left front side member joint 7 and the right front side member joint 8 designed by the bending resistance structure opening upward can reduce the intrusion of the dash and support the energy absorption of the front side member, and can realize the left front side member joint 7 . and the weight reduction of the right front side member joint 8; at the same time, the longitudinal structure of the left front side member 1, the right front side member 2, the left sill 3, the right side sill 4 and the middle channel 5, as well as the front wall lower cross member 6, the left front side member joint 7 and The lower body frame structure formed by the lateral structure of the right front side member joint 8 stabilizes the front wall through the front wall lower cross member 6, and transmits the collision force from the front side member to the floor through the three transmission paths of the middle tunnel 5, the left side sill 3 and the right side sill 4. transfer to achieve a stable and reliable frontal collision structure.

As shown in FIGS. 2-4 , in order to further optimize the transmission path of the collision force, the left front side member joint 7 includes a left front side member upper joint 701 and a left front side member lower joint 702 , and the left front side member upper joint 701 is connected to the The left front longitudinal beam lower joint 702 closes to the connecting end of the rear end of the left front longitudinal beam 1 to form a closed beam body; the right front longitudinal beam joint 8 includes a right front longitudinal beam upper joint 801 and a right front longitudinal beam lower joint 802. The right front longitudinal beam The upper beam joint 801 and the connecting end of the right front longitudinal beam lower joint 802 close to the rear end of the right front longitudinal beam 2 are buckled to form a closed beam body.

Specifically, as shown in FIGS. 2-4 , the left front side member lower joint 702 includes a first connection end 7021 , a second connection end 7022 and a third connection end 7023 , and the first connection end 7021 is connected to the left front The rear end of the side member 1, the second connection end 7022 is connected to the front end of the left side sill 3, the third connection end 7023 is connected to the left end of the front wall lower cross member 6; the lower joint of the right front side member 802 includes a fourth connection end 8021, a fifth connection end 8022 and a sixth connection end 8023, the fifth connection end 8022 is connected to the rear end of the right front side member 2, and the fifth connection end 8022 is connected to the At the front end of the right rocker 4 , the sixth connecting end 8023 is connected to the right end of the front wall lower cross member 6 . Through the first connection end 7021, the second connection end 7022 and the third connection end 7023 of the left front side member lower joint 702, a tee joint structure connecting the left front side member 1, the left side sill 3 and the cowl lower cross member 6 is formed on the left side, On the one hand, the collision force transmitted from the left front side member 1 is transmitted to the left side sill 3 through the first connecting end 7021 via the second connecting end 7022. On the other hand, the third connecting end 7023 is connected with the dash lower cross member 6 to support the left front side member. The stability of the joint 7 ensures the reliability of the entire lower body frame structure. The fourth connection end 8021 , the fifth connection end 8022 and the sixth connection end 8023 of the right front side member lower joint 802 form a tee joint structure on the right side that connects the right front side member 2 , the right side sill 4 and the cowl lower cross member 6 . It is symmetrical with the left side and has the same function as the left side, so it will not be repeated.

As shown in Figures 2-4, in order to further improve the bending deformation resistance of the left front longitudinal beam joint 7 and the right front longitudinal beam joint 8 and support the energy absorption of the front longitudinal beam, the left front longitudinal beam joint 7 and the right front longitudinal beam joint 8 A quadrilateral rib-like structure is arranged inside, and a rice-shaped rib-like structure is arranged inside the front wall lower beam 6 . The quadrilateral rib-like structure is conducive to the transmission of force, and the rice-shaped rib-like structure is more conducive to support.

As shown in Figures 2-4, in order to further improve the bending deformation resistance of the left front longitudinal beam joint 7 and the right front longitudinal beam joint 8 and support the energy absorption of the front longitudinal beam, the left front longitudinal beam upper joint 701 includes a first bottom plate 7011, which is composed of a The first side plates 7012 extending downward from both sides of the first bottom plate 7011 and the first inner rib 7013 extending downward from the middle of the first bottom plate 7011. The lower joint 702 of the left front longitudinal beam includes a second bottom plate 7024, A second side plate 7025 extending upward from both sides of the second bottom plate 7024 and a second inner rib 7026 extending upward from the middle of the second bottom plate 7024, the upper joint 701 of the left front longitudinal beam and the first connecting end 7021 is buckled to form a closed beam body; the upper joint 801 of the right front longitudinal beam includes a third bottom plate 8011, a third side plate 8012 extending downward from both sides of the third bottom plate 8011, and a third bottom plate 8011 extending from the middle of the third bottom plate The third inner rib 8013 extending downward, the right front longitudinal beam lower joint 802 includes a fourth bottom plate 8024 , a fourth side plate 8025 extending upward from both sides of the fourth bottom plate 8024 and upward from the middle of the fourth bottom plate 8024 The extended fourth inner rib 8026, the right front longitudinal beam upper joint 801 and the fourth connecting end 8021 are buckled to form a closed beam body; A fifth side plate 602 extending upward from both sides of the fifth bottom plate 601 and a fifth inner rib 603 extending upward from the middle of the fifth bottom plate 601 . The support of the front-end collision force is mainly realized by the bending resistance of the Z-direction ejection structure in the X-direction. The lower joint 702 and the right front longitudinal beam lower joint 802 form a beam-like structure with an upward opening, and are subjected to the X-direction transmission force through the X-direction layout of the second inner rib 7026 and the fourth inner rib 8026 . The upper joint 701 of the left front longitudinal beam and the upper joint 801 of the right front longitudinal beam adopt the Z-direction downward mold design, and are supported and strengthened by the first internal ribs 7013 and the second internal ribs 7026 . The upper joint 701 of the left front side member is buckled with the first connecting end 7021 to form a closed beam body for docking with the left front side member 1 , and the upper joint 801 of the right front side member is buckled with the fourth connection end 8021 to form a closed beam body to be connected with the right front side member 2 . docking. At the same time, the front wall lower cross member 6 adopts the Z-direction upward ejection design, the middle part supports both ends, and protects the collision root. Reliability of the entire flexural structure.

As shown in Figures 1-4, in order to further strengthen the support and reinforcement of the upper joint 701 of the left front longitudinal beam and the upper joint 801 of the right front longitudinal beam, and prevent the joints from turning up, the upper joint 701 of the left front longitudinal beam and the upper The inside of the joint 801 is provided with a m-shaped rib-like structure, wherein the first internal rib 7013 located inside the joint 701 of the left front longitudinal beam is a m-shaped rib-shaped structure, and is located in the third inner part of the upper joint 801 of the right front longitudinal beam The rib 8013 is a rice-shaped rib-like structure, and the rice-shaped rib-like structure is more conducive to support. In order to further realize that the left front longitudinal beam lower joint 702 and the right front longitudinal beam lower joint 802 bear the force transmission in the X direction of the collision and match the bending stability of the lower part, the left front longitudinal beam lower joint 702 and the right front longitudinal beam lower joint 802 A quadrilateral rib-like structure is provided inside, wherein the second inner rib 7026 located inside the left front longitudinal beam lower joint 702 is a quadrilateral rib-like structure, and the fourth inner rib 8026 located inside the right front longitudinal beam lower joint 802 is a quadrilateral rib-like structure, The quadrilateral rib-like structure is conducive to the transmission of force. In order to further realize the protection of front-end collision and intrusion, the front wall lower cross member 6 is provided with a rice-shaped rib-like structure, and the rice-shaped rib-shaped structure located inside the front wall lower cross member 6 is the fifth internal rib 603. The tendon structure is more conducive to support.

As shown in FIG. 1 , in order to further strengthen the stability of the connection between the left front side member joint 7 and the left rocker 3 , and the right front side member joint 8 and the right rocker 4 , the left front side member lower joint 702 is connected to the left rocker 3 at the connection point. The height of the side wall is greater than the height of the left door sill 3 , and the height of the side wall of the right front side member lower joint 802 at the connection with the right door sill 4 is greater than the height of the right door sill 4 . Specifically, the height of the second side plate 7025 located at the second connection end 7022 is greater than the height of the left door sill 3 , and the height of the fourth side plate 8025 located at the fifth connection end 8022 The height of the left door sill 3 is greater than the height of the left door sill 3, and the wall height of the left door sill 3 is enveloped by the left front longitudinal beam joint 7 and the wall height of the right door sill 4 is enveloped by the right front longitudinal beam joint 8, which can improve the stability of the connection.

As shown in FIG. 1 and FIG. 5 , in order to further optimize the lower body frame structure and the transmission path of the collision force, the lower body frame structure further includes a front cowl upper cross member 9 , a front seat front cross member 10 , a front seat The seat rear cross member 11 and the rear seat front cross member 12, the front wall upper cross member 9 is connected between the left front side member upper joint 701 and the right front side member upper joint 801, the front seat front cross member 9 10. The front seat rear beam 11 and the rear seat front beam 12 are sequentially connected between the left door sill 3 and the right door 4, and the middle channel 5 is connected to the front seat in sequence. The seat front beam 10 , the front seat rear beam 11 and the middle part of the rear seat front beam 12 are connected. The cowl upper cross member 9, the cowl lower cross member 6, the left front side member joint 7 and the right front side member joint 8 together form the front wall frame. The crisscross structure formed by the above structure is beneficial to improve the collision safety of the lower body frame; at the same time, the upper front cross member 9 can reduce the amount of front wall intrusion in the X direction, and support the upper joint 701 of the left front longitudinal beam in the Y direction and the right front longitudinal beam upper joint 801, thereby improving the stability of the upper structure.

As shown in FIG. 1 , in order to further optimize the transmission path of the collision force, the lower body frame structure further includes a left rear side member 13 , a right rear side member 14 , a rear floor cross member 15 , a left rear side member joint 16 and a right rear side member 16 . Side member joint 17, the rear floor cross member 15 is connected between the front end of the left rear side member 13 and the front end of the right rear side member 14; the left rear side member joint 16 and the right rear side member The joint 17 opens upward, the front end of the left rear side member joint 16 is respectively connected with the rear end of the left rocker 3 and the left end of the rear seat front cross member 12 , and the rear end of the left rear side member joint 16 is respectively connected The front end of the left rear longitudinal beam 13 and the left end of the rear floor cross beam 15 are respectively connected; the front end of the right rear longitudinal beam joint 17 is respectively connected with the rear end of the right rocker 4 and the front of the rear seat. The right end of the cross member 12 is connected, and the rear end of the right rear side member joint 17 is respectively connected with the front end of the right rear side member 14 and the right end of the rear floor cross member 15 . The lower body frame structure further includes a rear wall cross member 18 connected between the rear end of the left rear side member 13 and the rear end of the right rear side member 14 . The left rear side member joint 16 forms a three-way joint structure on the left side connecting the rear end of the left rocker 3 , the left end of the rear seat front cross member 12 , and the front end of the left rear side member 13 , which is beneficial to the transmission from the left rocker 3 . The force is transmitted rearward through the left rear side member joint 16 . The structure of the right rear longitudinal beam joint 17 is symmetrical with the left side, and the function is the same as that of the left side, so it is not repeated here.

As shown in FIG. 1 , in order to further improve the bending resistance of the left rear side member joint 16 and the right rear side member joint 17 , the left rear side member joint 16 includes a sixth bottom plate 1601 , which is formed by two sides of the sixth bottom plate 1601 . The sixth side plate 1602 extending upward and the sixth inner rib 1603 extending upward from the middle of the sixth bottom plate 1601 , the right rear longitudinal beam joint 17 includes a seventh bottom plate 1701 , and the seventh bottom plate 1701 has two sides extending upward from the seventh bottom plate 1701 . The extending seventh side plate 1702 and the seventh inner rib 1703 extending upward from the middle of the seventh bottom plate 1701 . The left rear longitudinal beam joint 16 and the right rear longitudinal beam joint 17 adopt the Z-direction upwardly ejected high-pressure vacuum casting structure, so that the left rear longitudinal beam joint 16 and the right rear longitudinal beam joint 17 form a beam-like structure with an upward opening, and pass through the high-pressure vacuum casting structure. Supported by two tendon structures.

In order to further support the left rear side member joint 16 and the right rear side member joint 17 , the left rear side member joint 16 and the right rear side member joint 17 are internally provided with a cross-shaped rib-like structure. The sixth internal rib 1603 located inside the left rear side member joint 16 is a cross-shaped rib-like structure, and the seventh internal rib 1703 located inside the right rear side member joint 17 is a cross-type rib-shaped structure, passing through the sixth internal rib 1603 and the seventh inner rib 1703 can achieve cross bracing at this joint.

It can be seen from the above description that the beneficial effect of the present invention is that, aiming at the collision requirements of pure electric vehicles, the present invention designs the collision key joint parts based on the requirements of improving the light weight. Supports front-end collision energy absorption and matching occupant safety protection through bending resistance. The problem of shortening the collision path due to the non-floor longitudinal beam structure of the pure electric vehicle is improved through the structure of the upper cowl beam 9 and the structure of the lower cowl beam 6, and the stability and safety of the entire lower body are fully guaranteed. At the same time, by using the anti-bending joint, the weight reduction effect of the present invention is remarkable. Compared with the existing technology, the anti-bending structure design of the front longitudinal beam joint can achieve a weight reduction of about 4kg on one side and 8 kg on both sides. The anti-bending structure of the rear longitudinal beam joint can achieve Compared with the existing technology, the design can achieve a weight reduction of about 3.5kg on one side and a total of 7kg on both sides.

The above disclosures are only preferred embodiments of the present invention, and of course, the scope of the rights of the present invention cannot be limited by this. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims (10)

1. A lower body frame structure, comprising a left front longitudinal beam, a right front longitudinal beam, a left door sill, a right door sill and a middle channel, wherein the lower body frame structure also comprises a front wall lower beam, a left front longitudinal beam joint and the right front longitudinal beam joint, the cowl lower cross member is located between the left sill and the right sill, and the middle part of the cowl lower cross member is connected with the front end of the middle channel; the left front longitudinal beam joint is connected to the The right front longitudinal beam joint opens upward, the left front longitudinal beam joint is respectively connected with the rear end of the left front longitudinal beam, the front end of the left rocker and the left end of the front wall lower cross member, and the right front longitudinal beam joint is respectively connected with the The rear end of the right front longitudinal member, the front end of the right rocker and the right end of the cowl lower cross member are connected. 2 . The frame structure of the lower vehicle body according to claim 1 , wherein the left front longitudinal beam joint and the right front longitudinal beam joint are internally provided with a quadrilateral rib-like structure. 3 . 3 . The lower body frame structure according to claim 1 , wherein a rice-shaped rib structure is arranged inside the front wall lower cross member. 4 . 4 . The lower body frame structure according to claim 1 , wherein the left front longitudinal beam joint comprises a left front longitudinal beam upper joint and a left front longitudinal beam lower joint, and the left front longitudinal beam upper joint is connected to the left front longitudinal beam joint. 5 . The lower beam joint closes to the connecting end of the rear end of the left front longitudinal beam to form a closed beam body; the right front longitudinal beam joint includes a right front longitudinal beam upper joint and a right front longitudinal beam lower joint, and the right front longitudinal beam upper joint is connected with the right front longitudinal beam. The connecting end of the lower joint of the longitudinal beam close to the rear end of the right front longitudinal beam is buckled to form a closed beam body. 5 . The lower body frame structure according to claim 4 , wherein the upper joint of the left front longitudinal beam and the upper joint of the right front longitudinal beam are provided with a m-shaped rib-like structure, and the lower left front longitudinal beam The joint and the lower joint of the right front longitudinal beam are internally provided with a quadrilateral tendon structure. 6 . The lower vehicle body frame structure according to claim 4 , wherein the height of the side wall of the lower joint of the left front side member at the connection with the left rocker is greater than the height of the left rocker, and the right front longitudinal The height of the side wall of the lower beam joint at the connection with the right sill is greater than the height of the right sill. 7. The lower body frame structure according to any one of claims 2-6, wherein the lower body frame structure further comprises a front wall upper beam, a front seat front beam, a front seat rear The cross member and the front cross member of the rear seat, the upper front cross member is connected between the upper joint of the left front longitudinal member and the upper joint of the right front longitudinal member, the front cross member of the front seat, the front seat The rear crossbeam and the front crossbeam of the rear seats are sequentially connected between the left sill and the right sill, and the middle aisle is connected to the front crossbeam of the front seat, the rear crossbeam of the front seat and the The middle part of the front beam of the rear seat is connected. 8 . The lower body frame structure according to claim 1 , wherein the lower body frame structure further comprises a left rear side member, a right rear side member, a rear floor cross member, a left rear side member joint and a right rear side member. 9 . A longitudinal beam joint, the rear floor beam is connected between the front end of the left rear longitudinal beam and the front end of the right rear longitudinal beam; the left rear longitudinal beam joint and the right rear longitudinal beam joint are opened upward, so The front end of the left rear side member joint is respectively connected with the rear end of the left rocker and the left end of the front cross member of the rear seat, and the rear end of the left rear side member joint is respectively connected with the front end of the left rear side member. and the left end of the rear floor cross member; the front end of the right rear longitudinal member joint is respectively connected with the rear end of the right rocker and the right end of the front cross member of the rear seat; The ends are respectively connected with the front end of the right rear longitudinal beam and the right end of the rear floor cross beam. 9 . The lower vehicle body frame structure according to claim 8 , wherein the left rear longitudinal beam joint and the right rear longitudinal beam joint are internally provided with cross-shaped rib-like structures. 10 . 10 . The lower vehicle body frame structure according to claim 8 , wherein the lower vehicle body frame structure further comprises a rear wall cross member, and the rear wall cross member is connected to the left rear longitudinal member. 11 . between the rear end of the right rear side member and the rear end of the right rear side member.

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