EMU car body underframe structure

Abstract

The present invention provides a motor vehicle body chassis structure, which belongs to the field of rail vehicle technology, and includes a framework assembly and a corrugated bottom plate laid on the framework assembly, wherein the framework assembly includes two end beams, two side beams, two groups of traction beams, two groups of bolsters, a plurality of longitudinally spaced cross beams, and two groups of in-track longitudinal beams, wherein the two groups of in-track longitudinal beams are respectively connected to the two groups of bolsters and extend toward the middle of the framework assembly; each group of in-track longitudinal beams includes two groups of trough beams, which are symmetrical and spaced around the longitudinal center axis of the framework assembly, one end of the trough beam is fixedly connected to the corresponding bolster beam, and the other end extends longitudinally along the framework assembly and spans at least three cross beams; wherein the trough beam has a wing surface that is attached to and fixedly connected to the corrugated bottom plate, and the lateral width of the wing surface gradually increases from the traction beam toward the extended end of the trough beam. The motor vehicle body chassis structure provided by the present invention can reduce the weight of the chassis and save costs.

Description

Technical Field

[0001] The invention belongs to the technical field of rail vehicles, and in particular relates to a motor vehicle body underframe structure. Background Art

[0002] The car body strength level of rail vehicles must meet the requirements of industry standards. At present, for EMUs with higher speeds, the longitudinal compression force loaded on the car body frame during operation can reach 2000kN, and the tensile force can reach 1500 kN. Among them, the longitudinal compression load will act directly on the traction beam, and then be transmitted step by step to the middle of the chassis through the longitudinal beam in the track. As the load gradually extends and transmits, it will eventually be evenly dispersed on the chassis floor.

[0003] At present, the longitudinal beams of the underframe structure of rail vehicles are usually made of trough-shaped carbon steel with the same width as the upper and lower wing surfaces. For this type of underframe structure, the load transfer area between the wing surface of the longitudinal beam and the underframe floor is concentrated, so the longitudinal force borne on the underframe floor in the connection area corresponding to the longitudinal beam is relatively large. Under the condition of meeting the load of conventional trains, if the same underframe structure is used on high-speed trains, it is necessary not only to increase the extension length of the longitudinal beam toward the middle of the underframe, but also to increase the thickness of the underframe floor or improve the plate strength grade of the underframe floor, which will cause a significant increase in the weight of the underframe structure and material costs. Summary of the invention

[0004] The embodiment of the present invention provides a motor vehicle body underframe structure, aiming to solve the problem of heavy weight and high cost of the current motor vehicle underframe structure.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a train body underframe structure is provided, comprising a frame assembly and a corrugated bottom plate laid on the frame assembly, wherein the frame assembly comprises two end beams, two side beams, two groups of traction beams, two groups of bolsters, a plurality of longitudinally spaced cross beams, and two groups of in-track longitudinal beams, wherein the two groups of in-track longitudinal beams are respectively connected to the two groups of bolsters and extend toward the middle of the frame assembly; each group of in-track longitudinal beams comprises two groups of trough beams, wherein the two groups of trough beams are symmetrically spaced about the longitudinal center axis of the frame assembly and are spaced apart, wherein one end of the trough beam is fixedly connected to the corresponding bolster, and the other end extends in the longitudinal direction of the frame assembly and spans at least three cross beams; wherein the trough beam has a wing surface which is attached to and fixedly connected to the corrugated bottom plate, and the lateral width of the wing surface gradually increases from the bolster toward the extending end of the trough beam.

[0006] In a possible implementation, each group of trough beams includes a plurality of beam sections aligned in the longitudinal direction of the framework assembly, and two ends of each beam section are respectively abutted against two adjacent cross beams and fixed by welding.

[0007] In some embodiments, the extended end of the trough beam is provided with two cross beams fixed back to back or face to face, and the two cross beams are defined as a composite beam, and the side wall of the composite beam facing away from the middle of the frame assembly is welded and fixed to the extended end of the trough beam; wherein, a reinforcing corrugated plate is provided on the side of the composite beam facing the middle of the frame assembly, one end of the reinforcing corrugated plate is welded and fixed to the side wall of the composite beam, and the other end is welded and fixed to one of the cross beams, and the reinforcing corrugated plate spans at least one cross beam; the reinforcing corrugated plate is fixedly connected to the corrugated bottom plate, and the corrugated grooves of the two are aligned.

[0008] Exemplarily, the reinforcing corrugated plate includes multiple sections, wherein one section of the reinforcing corrugated plate is located between the composite beam and the cross beam close to the composite beam, and the remaining reinforcing corrugated plates are arranged in sequence toward the middle of the frame assembly and are respectively distributed between two adjacent cross beams, and the two ends of the remaining reinforcing corrugated plates are respectively welded and fixed to the side walls of the corresponding two cross beams.

[0009] For example, the transverse width of each section of the reinforcing corrugated plate gradually increases from the composite beam to the middle of the frame assembly, and the transverse width of the reinforcing corrugated plate connected to the composite beam is greater than the maximum transverse width of the two groups of trough beams.

[0010] In a possible implementation, the crossbeam fixedly connected to one end of the reinforcing corrugated plate toward the middle of the frame assembly is a transition beam, and a reinforcing flat plate is provided on one side of the transition beam toward the middle of the frame assembly, one end of the reinforcing flat plate is welded and fixed to the side wall of the transition beam, and the other end is welded and fixed to the side wall of the crossbeam adjacent to the transition beam.

[0011] In some embodiments, the transverse width of the reinforced flat plate is greater than the maximum transverse width of the reinforced corrugated plate.

[0012] Exemplarily, one of the side beams has a break corresponding to the position of the vehicle door, and the break portion of the side beam is connected and fixed by a sill beam assembly; wherein the sill beam assembly includes an inner beam and a footrest beam; wherein the inner beam is fitted and fixed to the side wall of the side beam toward the middle of the frame assembly, and the two ends are respectively staggered with the portions of the side beam located on both sides of the break; the footrest beam is fitted and fixed to the bottom wall of the side beam, and the two ends are respectively staggered with the portions of the side beam located on both sides of the break; the footrest beam and the portion of the inner beam located within the break form a step structure.

[0013] For example, a groove aligned with the fracture is provided on the side of the inner beam facing outside the framework assembly, the side wall of the footrest beam facing the middle of the framework assembly is flush with the bottom of the groove, and the side wall of the footrest beam facing outside the framework assembly is flush with the side wall of the side beam away from the inner beam; wherein, the parts of the footrest beam located on both sides of the fracture are welded and fixed together with the bottom walls of the side beam and the bottom walls of the inner beam.

[0014] In some embodiments, a plurality of reinforcing ribs are spaced apart in the inner beam, and a plurality of reinforcing ribs are spaced apart in the portion where the side beam and the inner beam are staggered and fitted.

[0015] The beneficial effect of the EMU car body underframe structure provided by the present invention is that: compared with the prior art, the EMU car body underframe structure of the present invention adopts two groups of symmetrically distributed trough beams as the inner longitudinal beams of the track. Since the width of the wing surface where the trough beams are fixedly fitted with the corrugated bottom plate gradually widens from the bolster to the middle of the frame assembly, the contact width between the wing surface and the corrugated bottom plate gradually increases, so that the longitudinal load transmitted from the bolster to the trough beam can be gradually dispersed and transmitted to the corrugated bottom plate through the wing edge. On this basis, the trough beam only needs to cross three cross beams at least to completely disperse and transmit the longitudinal load to the corrugated bottom plate. Since there is no longitudinal load in the area after the longitudinal load is completely dispersed, the longitudinal load is gradually dispersed. The longitudinal force is borne by the inner-rail longitudinal beam, so the extension length of the inner-rail longitudinal beam can be reduced, which can not only reduce the weight of the chassis, but also reduce the material used for the trough beam, thereby saving costs. At the same time, the gradually widening contact area between the corrugated bottom plate and the wing edge in the area above the inner-rail longitudinal beam is conducive to the longitudinal load on the trough beam being transmitted to the corrugated bottom plate through the wing edge in a divergent state, thereby avoiding load concentration on the corrugated bottom plate in this area, so that the corrugated bottom plate can meet the longitudinal force bearing requirements of the EMU chassis without increasing the thickness or material strength, thereby further reducing the weight and avoiding the increase in cost due to the use of high-strength materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the three-dimensional structure of the EMU car body underframe structure (part near one end) provided in an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of a partial bottom view of the structure of the EMU car body underframe structure provided by an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the connection structure of the longitudinal beam in the rail used in the embodiment of the present invention;

[0019] Figure 4 A schematic diagram of the cross-sectional structure of the EMU car body underframe structure in the reinforced flat plate area provided by an embodiment of the present invention;

[0020] Figure 5 A schematic diagram of the cross-sectional structure of the EMU car body underframe structure in the reinforced corrugated plate area provided by an embodiment of the present invention;

[0021] Figure 6 A schematic diagram of the structure of a reinforced corrugated plate (a section thereof) used in an embodiment of the present invention;

[0022] Figure 7 This is a schematic structural diagram of a threshold beam assembly used in an embodiment of the present invention;

[0023] Figure 8 A schematic diagram of the cross-sectional structure of a door sill beam assembly used in an embodiment of the present invention;

[0024] Fig. 9 This is a schematic diagram of the structure of the inner beam used in an embodiment of the present invention.

[0025] In the figure: 10, corrugated bottom plate; 20, end beam; 30, side beam; 300, fracture; 40, traction beam; 50, cross beam; 501, composite beam; 502, transition beam; 60, inner longitudinal beam; 600, trough beam; 601, wing surface; 602, avoidance notch; 70, reinforced corrugated plate; 80, reinforced flat plate; 90, threshold beam assembly; 91, inner beam; 911, groove; 912, reinforcing rib plate; 92, pedal beam. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or indirectly on the other element. It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meanings of "multiple" and "several" are two or more, unless otherwise clearly and specifically defined. Specifically, in the description of the present invention, "longitudinal" and "lateral" represent the length direction and width direction of the vehicle body, respectively.

[0028] Please also read Figures 1 to 3Now, the EMU car body underframe structure provided by the present invention is described. The EMU car body underframe structure comprises a framework assembly and a corrugated bottom plate 10 laid on the framework assembly, wherein the framework assembly comprises two end beams 20, two side beams 30, two groups of traction beams 40, a plurality of longitudinally spaced cross beams 50, and two groups of in-track longitudinal beams 60, wherein the two groups of in-track longitudinal beams 60 are respectively connected to the two groups of traction beams 40 and extend toward the middle of the framework assembly; each group of in-track longitudinal beams 60 comprises two groups of trough beams 600, wherein the two groups of trough beams 600 are symmetrically spaced about the longitudinal center axis of the framework assembly and are spaced apart, wherein one end of the trough beam 600 is fixedly connected to the corresponding traction beam 40, and the other end extends in the longitudinal direction of the framework assembly and spans at least three cross beams 50; wherein the trough beam 600 has a wing surface 601 which is attached to and fixedly connected to the corrugated bottom plate 10, and the transverse width of the wing surface 601 gradually increases from the traction beam 40 toward the extended end of the trough beam 600.

[0029] It should be noted that the end beams 20, side beams 30, traction beams 40, pillow blocks and cross beams 50 used in the framework assembly are the same as those in the prior art unless further defined. The key in this embodiment is to utilize the inner-rail longitudinal beams 60 to disperse and transfer the longitudinal load of the traction beams 40 to the corrugated bottom plate 10, and to utilize the method of gradually increasing the fixed width between the wing edge and the corrugated bottom plate 10 to disperse the longitudinal load to the width of the entire corrugated bottom plate 10, so as to achieve the purpose that the middle area of ​​the framework assembly no longer relies on the inner-rail longitudinal beams 60. That is to say, after the inner-rail longitudinal beams 60 cross the three cross beams 50, specifically, the extended end of the inner-rail longitudinal beams 60 is fixedly connected to the fourth cross beam 50. At this time, the longitudinal load is basically dispersed to the entire width of the corrugated bottom plate 10. Therefore, the inner-rail longitudinal beams 60 are no longer required to be arranged in the area between the fourth cross beams 50 at the first end and the fourth cross beams 50 at the second end.

[0030] It should be emphasized here that in the prior art, due to the small connection contact area between the inner rail longitudinal beam 60 and the corrugated bottom plate 10, the longitudinal load on the inner rail longitudinal beam 60 can only be transmitted to the local area close to the inner rail longitudinal beam 60, so the load concentration phenomenon in this area is obvious, so it is necessary to strengthen the corrugated bottom plate 10 in this area. One way is to increase the plate thickness, and the other way is to enhance the strength grade of the material itself. In this embodiment, by using the trough beam 600 with gradually widened wing edges as the inner rail longitudinal beam 60, the connection width between the inner rail longitudinal beam 60 and the corrugated bottom plate 10 can be gradually increased, so that the longitudinal load is gradually dispersed to the entire surface width of the corrugated bottom plate 10, eliminating load concentration, and there is no need to replace the corrugated bottom plate 10 with a thicker thickness or a higher material strength grade. It not only avoids the increase in weight and cost, but also shortens the extension length of the inner rail longitudinal beam 60 to a certain extent, thereby promoting the lightweight of the chassis and saving material costs.

[0031] Compared with the prior art, the EMU car body underframe structure provided in this embodiment adopts two groups of symmetrically distributed trough beams 600 as the inner rail longitudinal beams 60. Since the width of the wing surface 601 to which the trough beam 600 and the corrugated bottom plate 10 are fixedly attached gradually widens from the bolster to the middle of the frame assembly, the contact width between the wing surface 601 and the corrugated bottom plate 10 gradually increases, so that the longitudinal load transmitted from the bolster to the trough beam 600 can be gradually dispersed and transmitted to the corrugated bottom plate 10 through the wing edge. On this basis, the trough beam 600 only needs to cross at least three cross beams 50 to completely disperse and transmit the longitudinal load to the corrugated bottom plate 10. Since the area after the longitudinal load is completely dispersed no longer relies on the rail The inner longitudinal beam 60 bears the longitudinal force, so the extension length of the inner longitudinal beam 60 can be reduced, which can not only reduce the weight of the chassis, but also reduce the material used for the trough beam 600, thereby saving costs. At the same time, the gradually widening contact area between the corrugated bottom plate 10 and the wing edge in the area above the inner longitudinal beam 60 is beneficial for the longitudinal load on the trough beam 600 to be transmitted to the corrugated bottom plate 10 through the wing edge in a divergent state, thereby avoiding load concentration on the corrugated bottom plate 10 in this area, so that the corrugated bottom plate 10 can meet the longitudinal force bearing requirements of the EMU chassis without increasing the thickness or material strength, thereby further reducing the weight and avoiding the increase in cost due to the use of high-strength materials.

[0032] Specifically, in this embodiment, each group of trough beams 600 includes multiple sections of beam bodies aligned in the longitudinal direction of the frame assembly, and the two ends of each section of the beam body are respectively abutted against and welded to two adjacent cross beams 50. Each section of the trough beam 600 and the corresponding two cross beams 50 are actually fixedly connected by plug welding. A section of the trough beam 600 is inserted between two adjacent cross beams 50 so that its two ends are respectively abutted against and welded to the opposite side walls of the two cross beams 50. It should be understood that the cross beams 50 are usually trough-shaped, and the notches of each cross beam 50 are in the same direction. Therefore, one of the opposite side walls of the two adjacent cross beams 50 is a vertical plane, and the other is a notch side. At this time, one end of the trough beam 600 is directly cut to form a vertical flat mouth and a vertical flat mouth. The straight plane can be welded and fixed, and the other end needs to be cut on the wing edge to form an avoidance notch 602, and then the end of the trough beam 600 is extended into the notch of the beam 50 and welded and fixed to the bottom wall of the groove of the beam 50, and at the same time, the stop wall of the avoidance notch 602 is abutted against the notch wall of the beam 50 and welded and fixed, that is, the cutting length of the avoidance notch 602 is the notch depth of the beam 50; in addition, it should be noted that after each section of the trough beam 600 is welded and fixed, it should be aligned along the longitudinal direction of the frame assembly to ensure the balance of the transfer of the longitudinal load.

[0033] To further improve the longitudinal load dispersion effect, please refer to Figures 1 to 5The extended end of the trough beam 600 is provided with two cross beams 50 fixed back to back or face to face, and the two cross beams 50 are defined as a combined beam 501, and the side wall of the combined beam 501 away from the middle of the frame assembly is welded and fixed to the extended end of the trough beam 600; wherein, a reinforcing corrugated plate 70 is provided on the side of the combined beam 501 facing the middle of the frame assembly, one end of the reinforcing corrugated plate 70 is welded and fixed to the side wall of the combined beam 501, and the other end is welded and fixed to one of the cross beams 50, and the reinforcing corrugated plate 70 at least spans across one cross beam 50; the reinforcing corrugated plate 70 is fixedly connected to the corrugated bottom plate 10, and the corrugated grooves of the two are aligned.

[0034] The extended end of the trough beam 600 uses two cross beams 50 to form a composite beam 501, so that the structural strength of the end area of ​​the longitudinal beam 60 in the track can be improved. Since the composite beam 501 and the corrugated bottom plate 10 are integrally connected in width, the width of the composite beam 501 (the sum of the widths of the two cross beams 50) can be used to improve the reinforcement effect of the corrugated bottom plate 10 in this area. On this basis, a reinforcing corrugated plate 70 is added outside the extended end of the longitudinal beam 60 in the track, and the reinforcing corrugated plate 70 is relatively fitted and fixed to the notch of the corrugated bottom plate 10. The function of the reinforcing corrugated plate 70 is to strengthen the corrugated bottom plate 10 outside the extended end of the longitudinal beam 60 in the track ( On the one hand, the reinforced corrugated plate 70 is used to reinforce the areas where load concentration is likely to occur, and on the other hand, the reinforced corrugated plate 70 is in integral contact with the inner bottom plate of the rail, so the force transmission is more balanced, thereby further dispersing the longitudinal load transmitted from the inner longitudinal beam 60 of the rail. It can be understood that the inner longitudinal beam 60 of the rail uses its gradually widening wing edge to convert the longitudinal load from a point to a line (i.e. a section of the width direction), and the reinforced corrugated plate 70 converts the line on the inner longitudinal beam 60 of the rail into a surface (i.e. the entire surface area that can be covered by the reinforced corrugated plate 70), thereby realizing a secondary divergence of the longitudinal load, which can further improve the balance of the longitudinal load in the width range after it is transferred to the corrugated bottom plate 10.

[0035] Specifically, in order to ensure the structural integrity of the crossbeam 50, please refer to Figure 2 and Figure 6 The reinforcing corrugated plate 70 includes multiple sections, one of which is located between the combined beam 501 and the cross beam 50 close to the combined beam 501, and the remaining reinforcing corrugated plates 70 are arranged in sequence toward the middle of the frame assembly and are respectively distributed between two adjacent cross beams 50, and the two ends of the remaining reinforcing corrugated plates 70 are respectively welded and fixed to the side walls of the corresponding two cross beams 50.

[0036] It should be noted that, similar to the connection method of the segmented trough beam 600, after a section of reinforced corrugated plate 70 is inserted between two adjacent beams 50, the end facing the notch side can be cut and corrected so that the corrugated surface at its end extends into the notch of the beam 50 and is welded and fixed to the bottom wall of the groove, and the stop wall formed after cutting is abutted against the notch wall of the beam 50 and welded and fixed.

[0037] In this embodiment, the transverse width of each section of the reinforcing corrugated plate 70 gradually increases from the combined beam 501 to the middle of the frame assembly, and the transverse width of the reinforcing corrugated plate 70 connected to the combined beam 501 is greater than the maximum transverse width of the two groups of trough beams 600.

[0038] According to the actual size of the longitudinal load, two sections of reinforced corrugated plates 70 can be used, wherein the width of one section of the reinforced corrugated plate 70 close to the composite beam 501 is greater than the maximum width of the longitudinal beam 60 in the rail, and the width of the other section of the reinforced corrugated plate 70 is greater than the width of the previous section, thereby realizing the step-by-step divergence of the longitudinal load, improving the balance of force transmission, and reducing or avoiding the load concentration phenomenon.

[0039] For some possible implementations, see Figure 2 and Figure 4 The cross beam 50 fixedly connected to one end of the reinforcing corrugated plate 70 toward the middle of the frame assembly is a transition beam 502, and a reinforcing plate 80 is provided on one side of the transition beam 502 toward the middle of the frame assembly, and one end of the reinforcing plate 80 is welded and fixed to the side wall of the transition beam 502, and the other end is welded and fixed to the side wall of the cross beam 50 adjacent to the transition beam 502. Specifically, in this embodiment, the transverse width of the reinforcing plate 80 is greater than the maximum transverse width of the reinforcing corrugated plate 70.

[0040] By providing a reinforcing flat plate 80 at the end of the reinforcing corrugated plate 70, the width of the reinforcing flat plate 80 is further increased relative to the reinforcing corrugated plate 70, so that the longitudinal load dispersed by the reinforcing corrugated plate 70 is further dispersed and finally transmitted to the corrugated bottom plate 10, so that the loads borne by various regions of the corrugated bottom plate 10 in the width direction are basically the same, so that the corrugated bottom plate 10 can have the ability to withstand the longitudinal load only by relying on its own structural strength, without relying on thickening or reinforcing the material grade, thereby achieving weight reduction and cost savings; in addition, it should be noted that since the longitudinal load reaching the reinforcing flat plate 80 has been dispersed by the reinforcing corrugated plate 70, the longitudinal load per unit area has been greatly reduced at this time, so the reinforcing flat plate 80 is fixed to the corrugated bottom plate 10 to meet the load-bearing requirements, and there is no need to use corrugated plates with relatively high weight and cost, thereby helping to reduce the overall weight of the chassis and save costs.

[0041] It is important to understand that, combined with Figure 1 , Figures 7 to 9In the present embodiment, one of the side beams 30 has a break 300 corresponding to the position of the vehicle door, and the break 300 of the side beam 30 is connected and fixed by the door sill beam assembly 90; wherein the door sill beam assembly 90 includes an inner beam 91 and a footrest beam 92; wherein the inner beam 91 is fitted and fixed to the side wall of the side beam 30 toward the middle of the framework assembly, and the two ends are respectively staggered with the parts of the side beam 30 located on both sides of the break 300; the footrest beam 92 is fitted and fixed to the bottom wall of the side beam 30, and the two ends are respectively staggered with the parts of the side beam 30 located on both sides of the break 300; the footrest beam 92 and the inner beam 91 located within the break 300 form a step structure.

[0042] Usually, a door is provided on one side of a vehicle, so a break 300 is provided on the side beam 30 located on the one side, and the break 300 is connected by a door sill beam assembly 90. That is to say, the side beam 30 on the one side is actually a three-section combination structure of two sections of side beams 30 and a section of door sill beam assembly 90. In order to ensure the structural strength at the break 300, an inner beam 91 and a footrest beam 92 are used to stagger and weld the inner wall and the bottom wall of the side beam 30 on both sides of the break 300, respectively, to form a step structure for passengers to step on when getting on and off the vehicle. That is to say, the door sill beam assembly 90 not only serves as a connector connecting the break 300 of the side beam 30, but also forms a step that meets the needs of getting on and off the vehicle, thereby meeting the structural strength requirements while also achieving functional requirements.

[0043] Specifically, the inner beam 91 is provided with a groove 911 aligned with the cutout 300 on the side facing outside the frame assembly, the side wall of the pedal beam 92 facing the middle of the frame assembly is flush with the bottom of the groove 911, and the side wall of the pedal beam 92 facing outside the frame assembly is flush with the side wall of the side beam 30 away from the inner beam 91; wherein, the parts of the pedal beam 92 located on both sides of the cutout 300 are welded and fixed together with the bottom wall of the side beam 30 and the bottom wall of the inner beam 91. Multiple reinforcing ribs 912 are distributed at intervals in the inner beam 91, and multiple reinforcing ribs 912 are also distributed at intervals in the part where the side beam 30 and the inner beam 91 are staggered and fitted.

[0044] By setting the groove 911, the step surface width of the step structure can be made larger than the top surface width of the footrest beam 92, thereby increasing the stepping space. At the same time, surface contact can be formed between the footrest beam 92 and the bottom wall of the inner beam 91 and the bottom wall of the side beam 30. After welding and fixing, the three can be connected as one, thereby improving the structural strength. In addition, in order to further improve the structural strength of this area, the side beam 30 is implanted with reinforcing ribs 912 in the area on both sides of the fracture 300. At the same time, due to the existence of the groove 911, the inner beam 91 is also implanted with reinforcing ribs 912 to avoid deformation caused by frequent stepping on it.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A train body underframe structure, comprising a frame assembly and a corrugated floor plate laid on the frame assembly, wherein the frame assembly comprises two end beams, two side beams, two groups of traction beams, two groups of bolsters, a plurality of cross beams spaced longitudinally, and two groups of in-track longitudinal beams, wherein the two groups of in-track longitudinal beams are respectively connected to the two groups of bolsters and extend toward the middle of the frame assembly; characterized in that: Each group of the inner longitudinal beams of the rail includes two groups of trough beams, the two groups of trough beams are symmetrical and spaced apart with the longitudinal center axis of the frame assembly as the center, one end of the trough beam is fixedly connected to the corresponding bolster beam, and the other end extends in the longitudinal direction of the frame assembly and spans at least three of the cross beams; wherein the trough beam has an airfoil adhered to and fixedly connected to the corrugated bottom plate, and the transverse width of the airfoil gradually increases from the bolster toward the extending end of the trough beam; The extended end of the trough beam is provided with two cross beams fixed back to back or face to face, and the two cross beams are defined as a combined beam, and the side wall of the combined beam away from the middle of the frame assembly is welded and fixed to the extended end of the trough beam; wherein, a reinforcing corrugated plate is provided on the side of the combined beam facing the middle of the frame assembly, one end of the reinforcing corrugated plate is welded and fixed to the side wall of the combined beam, and the other end is welded and fixed to one of the cross beams, and the reinforcing corrugated plate spans at least one of the cross beams; the reinforcing corrugated plate is fixedly connected to the corrugated bottom plate, and the corrugated grooves of the two are aligned.

2. The EMU vehicle body underframe structure according to claim 1, characterized in that: Each group of the trough beams comprises a plurality of beam sections aligned in the longitudinal direction of the framework assembly, and two ends of each beam section are respectively abutted against and welded to two adjacent cross beams.

3. The EMU vehicle body underframe structure according to claim 1, characterized in that: The reinforcing corrugated plate includes multiple sections, one section of the reinforcing corrugated plate is located between the combined beam and the cross beam close to the combined beam, and the remaining reinforcing corrugated plates are arranged in sequence toward the middle of the framework assembly and are respectively distributed between two adjacent cross beams, and both ends of the remaining reinforcing corrugated plates are respectively welded and fixed to the side walls of the corresponding two cross beams.

4. The EMU vehicle body underframe structure according to claim 3, characterized in that: The transverse width of each section of the reinforcing corrugated plate gradually increases from the combined beam to the middle of the framework assembly, and the transverse width of the reinforcing corrugated plate connected to the combined beam is greater than the maximum transverse width of the two groups of trough beams.

5. The EMU vehicle body underframe structure according to claim 1, characterized in that: The cross beam fixedly connected to one end of the reinforcing corrugated plate toward the middle of the framework assembly is a transition beam, and a reinforcing flat plate is provided on one side of the transition beam toward the middle of the framework assembly, one end of the reinforcing flat plate is welded and fixed to the side wall of the transition beam, and the other end is welded and fixed to the side wall of the cross beam adjacent to the transition beam.

6. The EMU vehicle body underframe structure according to claim 5, characterized in that: The transverse width of the reinforcing flat plate is greater than the maximum transverse width of the reinforcing corrugated plate.

7. The EMU vehicle body underframe structure according to any one of claims 1 to 6, characterized in that: One of the side beams has a break corresponding to the position of the vehicle door, and the break of the side beam is connected and fixed by a door sill beam assembly; wherein the door sill beam assembly comprises: An inner beam is fixedly attached to the side wall of the side beam toward the middle of the frame assembly, and two ends thereof are respectively staggered with the portions of the side beam located on both sides of the fracture; A pedal beam is fixedly fitted with the bottom wall of the side beam, and two ends thereof are respectively staggered with the portions of the side beam located on both sides of the fracture; Wherein, the pedal beam and the inner beam form a step structure at the position within the fracture.

8. The EMU vehicle body underframe structure according to claim 7, characterized in that: A groove aligned with the fracture is provided on the side of the inner beam facing outside the framework assembly, the side wall of the pedal beam facing the middle of the framework assembly is flush with the bottom of the groove, and the side wall of the pedal beam facing outside the framework assembly is flush with the side wall of the side beam facing away from the inner beam; wherein the parts of the pedal beam located on both sides of the fracture are welded and fixed together with the bottom wall of the side beam and the bottom wall of the inner beam.

9. The EMU vehicle body underframe structure according to claim 7, characterized in that: A plurality of reinforcing ribs are distributed at intervals in the inner beam, and a plurality of reinforcing ribs are also distributed at intervals in the portion where the side beam and the inner beam are staggered and bonded.

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