Auxiliary frame structure and vehicle

Abstract

The auxiliary frame structure comprises a front cross beam, a rear cross beam, a left longitudinal beam and a right longitudinal beam, the front cross beam, the rear cross beam, the left longitudinal beam and the right longitudinal beam are connected in a welded mode, at least parts of the front cross beam, the rear cross beam, the left longitudinal beam and the right longitudinal beam are welded pipes, pipe cavities are formed in the welded pipes, and the pipe cavities are formed by butt joint of the two ends of plate-shaped sectional materials. According to the auxiliary frame structure, at least parts of the front cross beam, the rear cross beam, the left longitudinal beam and the right longitudinal beam are the welded pipes, the pipe cavities are formed in the welded pipes, and the pipe cavities are formed by butt joint of the two ends of the plate-shaped sectional materials, so that the number of welding seams on the auxiliary frame and the area covered by the welding seams can be well reduced, and the welding efficiency is improved. The risk of fatigue failure at the welding seam on the auxiliary frame structure can be reduced, and the overall weight of the auxiliary frame assembly is reduced, so that the durability and the light weight level of the auxiliary frame structure are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle parts, in particular to a subframe structure and a vehicle. Background Art

[0002] The function of the front subframe is to block vibration and noise, reduce their direct entry into the carriage, improve the NVH performance of the whole vehicle, and also support the suspension and powertrain structures, protect the components inside the subframe framework, etc. However, the subframe structure in the related art is usually formed by welding stamping sheet metal parts. For example, the front crossbeam is usually formed by buckling and overlapping welding of an upper beam body and a lower beam body, resulting in a large number of welding positions and a wide coverage area on the subframe structure. And fatigue failure is more likely to occur at the welds, directly affecting the stability and durability of the subframe. Therefore, improvement is needed. Summary of the Utility Model

[0003] A subframe structure is proposed in the first aspect of the utility model, and the subframe structure has the advantages of strong durability and high lightweight level.

[0004] The subframe structure according to the embodiment of the first aspect of the utility model includes a front crossbeam, a rear crossbeam, a left longitudinal beam and a right longitudinal beam which are connected by welding, wherein at least part of the front crossbeam, the rear crossbeam, the left longitudinal beam and the right longitudinal beam is a welded pipe, a pipe cavity is arranged in the welded pipe, and the pipe cavity is formed by butt-jointing the two ends of a plate-shaped profile.

[0005] For the subframe structure according to the embodiment of the first aspect of the utility model, at least part of the front crossbeam, the rear crossbeam, the left longitudinal beam and the right longitudinal beam is a welded pipe, which can preferably reduce the number of welds and the area covered by the welds on the subframe, reduce the risk of fatigue failure at the welds on the subframe structure and reduce the overall weight of the subframe assembly, so as to improve the durability and lightweight level of the subframe structure.

[0006] According to some embodiments of the utility model, the cross-section of the pipe cavity is arc-shaped; and / or, a weld is arranged at the butt-joint of the two ends of the plate-shaped profile.

[0007] According to some embodiments of the utility model, the wall thickness of the welded pipe is different in the extending direction.

[0008] According to some embodiments of the utility model, the pipe wall of the welded pipe is a flexible rolled piece.

[0009] According to some embodiments of the utility model, in the direction from the two ends of the welded pipe to the center, the wall thickness of the welded pipe shrinks.

[0010] According to some embodiments of the present utility model, the welded pipe includes a first pipe section, a second pipe section, and a third pipe section. There are two second pipe sections and two third pipe sections. The two second pipe sections are respectively connected to both ends of the first pipe section. One third pipe section is connected to one end of the second pipe section far from the first pipe section, and the other third pipe section is connected to the other end of the second pipe section far from the first pipe section. The wall thickness of the first pipe section is less than that of the third pipe section, and the wall thickness of the second pipe section gradually decreases in the direction towards the first pipe section.

[0011] According to some embodiments of the present utility model, the wall thickness range of the first pipe section is 2.0 mm to 3.5 mm; and / or, the length range of the first pipe section is 200 mm to 600 mm.

[0012] According to some embodiments of the present utility model, the difference between the maximum wall thickness and the minimum wall thickness of the second pipe section is not greater than 2 mm, and the wall thickness change gradient range of the second pipe section is 1:50 to 1:200; and / or, the length range of the second pipe section is 50 mm to 200 mm.

[0013] According to some embodiments of the present utility model, the wall thickness range of the third pipe section is 1.8 mm to 4.0 mm; and / or, the length range of the third pipe section is 150 mm to 500 mm.

[0014] According to some embodiments of the present utility model, the weld of the welded pipe is located on one side of the welded pipe in the first direction, and the first direction is perpendicular to the up-down direction and perpendicular to the extension direction of the welded pipe.

[0015] According to some embodiments of the present utility model, the weld of the welded pipe is arranged adjacent to the lower end of the welded pipe.

[0016] According to some embodiments of the present utility model, adjacent two welded pipes are connected by butt welding.

[0017] According to some embodiments of the present utility model, the welded pipe is an internally high-pressure formed part; and / or, the front crossbeam, the left longitudinal beam, and the right longitudinal beam are welded pipes, and the rear crossbeam is a stamping and splicing welded part.

[0018] The second aspect of the present utility model proposes a vehicle.

[0019] The vehicle according to the embodiments of the second aspect of the present utility model includes the above-mentioned subframe structure.

[0020] According to the vehicle of the second aspect embodiment of the present utility model, at least part of the front cross member, rear cross member, left longitudinal beam, and right longitudinal beam is a welded pipe, which can preferably reduce the number of welds on the subframe and the area covered by the welds, can reduce the risk of fatigue failure at the welds on the subframe structure, and reduce the overall weight of the subframe assembly, so as to improve the durability performance and lightweight level of the subframe structure.

[0021] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present utility model. Description of the Drawings

[0022] Figure 1 is a top view of the subframe structure according to the embodiment of the present utility model;

[0023] Figure 2 is a schematic diagram of the welded pipe of the subframe structure according to the embodiment of the present utility model;

[0024] Figure 3 is a partial cross-sectional view of the welded pipe of the subframe structure according to the embodiment of the present utility model;

[0025] Figure 4 is a schematic diagram of the front cross member of the subframe structure according to the embodiment of the present utility model;

[0026] Figure 5 is a schematic diagram of the left longitudinal beam of the subframe structure according to the embodiment of the present utility model;

[0027] Figure 6 is a schematic diagram of the connecting part of the welded pipe of the subframe structure according to the embodiment of the present utility model;

[0028] Figure 7 is a schematic diagram of the welding position of two welded pipes of the subframe structure according to the embodiment of the present utility model.

[0029] Reference Signs:

[0030] 100, subframe structure; 10, front cross member; 20, rear cross member; 30, left longitudinal beam; 40, right longitudinal beam; 1, welded pipe; 11, first pipe section; 12, second pipe section; 13, third pipe section; 14, first weld; 15, connecting part; 16, avoidance notch; 2, second weld. Detailed Embodiments

[0031] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present utility model and should not be construed as limiting the present utility model.

[0032] The following disclosure provides many different embodiments or examples for implementing different structures of the present utility model. To simplify the disclosure of the present utility model, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present utility model. In addition, the present utility model may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present utility model provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the applicability of other processes and / or the use of other materials.

[0033] The subframe structure 100 according to an embodiment of the first aspect of the present utility model will be described below with reference to the accompanying drawings.

[0034] As Figures 1 to 7 shown, the subframe structure 100 according to an embodiment of the first aspect of the present utility model includes a front cross member 10, a rear cross member 20, a left longitudinal beam 30, and a right longitudinal beam 40 that are welded together. Among them, at least part of the front cross member 10, the rear cross member 20, the left longitudinal beam 30, and the right longitudinal beam 40 is a welded pipe 1. A pipe cavity is provided inside the welded pipe 1, and the pipe cavity is formed by butt-jointing the two ends of a plate-shaped profile. That is to say, at least part of the front cross member 10, the rear cross member 20, the left longitudinal beam 30, and the right longitudinal beam 40 is made of the welded pipe 1. It can be understood that the welded pipe 1 is formed by curling a plate-shaped profile, opposing the curled ends, and butt-welding them. The formation of the welded pipe 1 only requires a weld seam at the butt-welding position, such as Figure 2 the first weld seam 14 in the figure, and since there is an overlap amount between the two parts that do not need to be welded during butt-welding, the weld area on the welded pipe 1 can be reduced.

[0035] Therefore, by making at least part of the front cross member 10, the rear cross member 20, the left longitudinal beam 30, and the right longitudinal beam 40 of the welded pipe 1, the number of weld seams on the subframe and the area covered by the weld seams can be better reduced. The risk of fatigue failure at the weld seams on the subframe structure 100 can be reduced, and the overall weight of the subframe assembly can be reduced to improve the durability performance and lightweight level of the subframe structure 100. In addition, compared with sheet metal welding, the front cross member 10, the rear cross member 20, the left longitudinal beam 30, or the right longitudinal beam 40 made of the welded pipe 1 requires fewer molds, so the number of molds required for the production of the subframe assembly can be reduced to lower the production and processing cost of the subframe structure 100.

[0036] It should be noted that one of the front cross member 10, rear cross member 20, left longitudinal beam 30 and right longitudinal beam 40 can be the welded pipe 1 structure, such as the front cross member 10 being the welded pipe 1 and so on. It can also be that multiple of the front cross member 10, rear cross member 20, left longitudinal beam 30 and right longitudinal beam 40 are the welded pipe 1 structure, such as the left longitudinal beam 30 and the right longitudinal beam 40 being the welded pipe 1 and so on. It can also be that the front cross member 10, rear cross member 20, left longitudinal beam 30 and right longitudinal beam 40 are all the welded pipe 1. There is no specific limitation here.

[0037] According to the subframe structure 100 of the first aspect embodiment of the present invention, at least part of the front cross member 10, rear cross member 20, left longitudinal beam 30 and right longitudinal beam 40 is the welded pipe 1, which can preferably reduce the number of welds on the subframe and the area covered by the welds, can reduce the risk of fatigue failure at the welds on the subframe structure 100 and reduce the overall weight of the subframe assembly, so as to improve the durability performance and lightweight level of the subframe structure 100.

[0038] According to some embodiments of the present invention, the cross section of the pipe cavity is arc-shaped, which can reduce the cracking risk. There is a weld at the butt joint of both ends of the plate-shaped profile, which can reduce the weld area on the welded pipe 1, thereby reducing the cracking risk at the weld.

[0039] According to some embodiments of the present invention, the wall thickness of the welded pipe 1 is different in the extending direction. That is to say, there are at least multiple parts with different wall thicknesses in the extending direction of the welded pipe 1. Among them, it can be understood that in the pipe beam structures such as the front cross member 10, rear cross member 20, left longitudinal beam 30 and right longitudinal beam 40, the stress distributions at multiple positions in the extending direction are different. For example, there can be high stress areas and low stress areas on the same pipe beam structure. Therefore, the wall thickness of the corresponding area on the welded pipe 1 can be adjusted according to the stress distribution on the pipe beam structure. For example, the wall thickness of the low stress area can be thinned, so as to save the production materials of the subframe structure 100 while ensuring the overall strength of the subframe structure 100, so as to reduce the weight and production cost of the subframe structure 100.

[0040] Among them, it should be noted that the thickness distribution, welded pipe 1 size and strength of the pipe beam structures in each area on the subframe structure 100 can be obtained based on CAE analysis. By thickening the wall thickness of the high stress areas on the pipe beam structures in each area of the subframe structure and thinning the wall thickness of the high stress areas on the pipe beam structures in each area of the subframe structure, the cost and weight of the subframe structure 100 can be reduced while ensuring the strength of the subframe structure 100.

[0041] According to some embodiments of the present utility model, the pipe wall of the welded pipe 1 is a flexible rolled piece. Among them, the flexible rolling forming process has the advantages of high material utilization rate, high production shape flexibility, and fast production efficiency, and can realize tubular parts with different wall thickness regions designed with the same material, so as to reduce the production cost of the welded pipe 1, and can be processed according to the wall thickness requirements of different regions of the welded pipe 1 to improve the design flexibility of the welded pipe 1.

[0042] According to some embodiments of the present utility model, in the direction from both ends of the welded pipe 1 to the center, the wall thickness of the welded pipe 1 decreases. It can be understood that after the welded pipe 1 is welded to form the subframe structure 100, such as the front cross member 10 being the welded pipe 1, in the subframe structure 100, the left and right ends of the front cross member 10 are respectively welded to the left longitudinal beam 30 and the right longitudinal beam 40, and the connection positions of the front cross member 10, the left longitudinal beam 30, and the right longitudinal beam 40 are high stress regions. Therefore, by setting the thickness of both ends of the welded pipe 1 to a relatively thick size, the strength of the connection positions of both ends of the welded pipe 1 for connecting with the pipe beam structure can be ensured, and by thinning the wall thickness of the low stress region in the middle of the welded pipe 1, the weight and cost of the welded pipe 1 can be reduced, so as to improve the lightweight level of the subframe structure 100 while ensuring the strength of the subframe structure 100.

[0043] According to some embodiments of the present utility model, the welded pipe 1 includes a first pipe section 11, a second pipe section 12, and a third pipe section 13. There are two second pipe sections 12 and two third pipe sections 13. The two second pipe sections 12 are respectively connected to both ends of the first pipe section 11. One third pipe section 13 is connected to one end of a second pipe section 12 away from the first pipe section 11, and the other third pipe section 13 is connected to the other end of the other second pipe section 12 away from the first pipe section 11. The wall thickness of the first pipe section 11 is less than the wall thickness of the third pipe section 13, and the wall thickness of the second pipe section 12 gradually decreases in the direction towards the first pipe section 11. That is to say, in the direction towards the first pipe section 11, the third pipe section 13, the second pipe section 12, and the first pipe section 11 are connected in sequence. Through the second pipe section 12, the wall thickness transformation between the first pipe section 11 and the third pipe section 13 can be better realized to ensure the smooth production of different wall thickness regions in the welded pipe 1.

[0044] According to some embodiments of the present utility model, the wall thickness range of the first pipe section 11 is 2.0 mm to 3.5 mm. That is, the wall thickness of the first pipe section 11 is controlled within the range of 2.0 mm to 3.5 mm. For example, the wall thickness of the first pipe section 11 can be 2.0 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3.1 mm, 3.3 mm, 3.5 mm, etc., and no specific limitation is made here. Thus, it is possible to avoid the excessive wall thickness of the first pipe section 11 from increasing the weight and production cost of the welded pipe 1, and at the same time, it is possible to avoid the too thin wall thickness of the first pipe section 11 from affecting the strength at the first pipe section 11, so that the weight and production cost of the welded pipe 1 can be reduced while ensuring the strength at the first pipe section 11.

[0045] According to some embodiments of the present utility model, the length range of the first pipe section 11 is 200 mm to 600 mm. That is, the dimension of the first pipe section 11 in the extending direction of the welded pipe 1 is controlled within the range of 200 mm to 600 mm. For example, the dimension of the first pipe section 11 in the extending direction of the welded pipe 1 can be 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, 550 mm, 600 mm, etc., and no specific limitation is made here. Thus, it is possible to avoid the too long length of the first pipe section 11 from being easily bent and affecting the strength at the first pipe section 11, and at the same time, it is possible to avoid the too short length of the first pipe section 11 from having too small a reduction in the weight and cost of the welded pipe 1, so that the weight and cost of the welded pipe 1 can be effectively reduced while ensuring the structural strength at the first pipe section 11.

[0046] According to some embodiments of the present utility model, the difference between the maximum wall thickness and the minimum wall thickness of the second pipe section 12 is not greater than 2 mm, and the wall thickness change gradient range of the second pipe section 12 is 1:50 to 1:200. Herein, the wall thickness change gradient is the ratio of the wall thickness change value of the second pipe section 12 to the length of the second pipe section 12. By controlling the difference between the maximum wall thickness and the minimum wall thickness of the second pipe section 12 within the range not greater than 2 mm and the wall thickness change gradient range of the second pipe section 12 within the range of 1:50 to 1:200, the requirements for the flexible rolling forming process can be reduced, so as to reduce the production and processing difficulty of the welded pipe 1. Among them, the difference between the maximum wall thickness and the minimum wall thickness of the second pipe section 12 can be 2 mm, 1.9 mm, 1.8 mm, 1.7 mm, 1.6 mm, 1.5 mm, 1.4 mm, etc., and the wall thickness change gradient of the second pipe section 12 can be 1:50, 1:70, 1:90, 1:100, 1:130, 1:150, 1:200, etc., and no specific limitation is made here.

[0047] According to some embodiments of the present utility model, the length range of the second pipe section 12 is 50 mm to 200 mm. That is, the dimension of the second pipe section 12 in the extending direction of the welded pipe 1 is controlled within the range of 50 mm to 200 mm. For example, the dimension of the second pipe section 12 in the extending direction of the welded pipe 1 can be 50 mm, 60 mm, 80 mm, 110 mm, 130 mm, 150 mm, 170 mm, 200 mm, etc., and no specific limitation is made here. Thus, it is possible to avoid the difficulty of flexible rolling processing caused by the too long or too short length of the second pipe section 12, so as to reduce the production and processing difficulty of the welded pipe 1.

[0048] According to some embodiments of the present utility model, the wall thickness range of the third pipe section 13 is 1.8 mm to 4.0 mm. That is, the wall thickness of the third pipe section 13 is controlled within the range of 1.8 mm to 4.0 mm. For example, the wall thickness of the third pipe section 13 can be 1.8 mm, 2.0 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3.1 mm, 3.3 mm, 3.5 mm, 4.0 mm, etc., and no specific limitation is made here. Thus, it is possible to avoid the increase in the weight and production cost of the welded pipe 1 due to the too thick wall thickness of the third pipe section 13, and at the same time, it is possible to avoid the influence on the strength at the third pipe section 13 due to the too thin wall thickness of the third pipe section 13. Therefore, it is possible to reduce the weight and production cost of the welded pipe 1 while ensuring the strength at the third pipe section 13.

[0049] According to some embodiments of the present utility model, the length range of the third pipe section 13 is 150 mm to 500 mm. That is, the dimension of the third pipe section 13 in the extending direction of the welded pipe 1 is controlled within the range of 150 mm to 500 mm. For example, the dimension of the third pipe section 13 in the extending direction of the welded pipe 1 can be 150 mm, 180 mm, 220 mm, 260 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, etc., and no specific limitation is made here. Thus, it is possible to avoid the increase in the weight and cost of the welded pipe 1 due to the too long length of the third pipe section 13, and at the same time, it is possible to avoid the influence on the strength strengthening effect of the third pipe section 13 on the corresponding area of the welded pipe 1 due to the too short length of the third pipe section 13. Therefore, it is possible to effectively reduce the weight and cost of the welded pipe 1 while ensuring the strength strengthening effect of the third pipe section 13 on the corresponding area of the welded pipe 1.

[0050] According to some embodiments of the present utility model, the weld seam of the welded pipe 1 is located on one side of the welded pipe 1 in the first direction, and the first direction is perpendicular to the up-down direction and perpendicular to the extending direction of the welded pipe 1. For example, the front cross member 10 is a welded pipe 1, and the weld seam of the front cross member 10, i.e., the first weld seam 14, is located on the front side or the rear side of the front cross member 10. Among them, since the main stress direction of the front cross member 10, the rear cross member 20, the left longitudinal beam 30, and the right longitudinal beam 40 of the subframe structure 100 is the up-down direction. Therefore, by arranging the weld seam of the welded pipe 1 on the side of the welded pipe 1 in the first direction, the influence on the weld seam area when the welded pipe 1 is stressed can be reduced, so as to improve the durability of the subframe structure 100.

[0051] According to some embodiments of the present utility model, the weld seam of the welded pipe 1 is arranged adjacent to the lower end of the welded pipe 1. Among them, the top surface of the subframe structure 100 acts as the main stress position, and the high stress area is relatively concentrated. Therefore, by arranging the weld seam of the welded pipe 1, i.e., the first weld seam 14, adjacent to the lower end of the welded pipe 1, the distance between the first weld seam 14 and the high stress area on the welded pipe 1 can be increased, so as to reduce the influence on the first weld seam 14 when the welded pipe 1 is stressed, so as to improve the durability of the subframe structure 100.

[0052] According to some embodiments of the present utility model, adjacent two welded pipes 1 are connected by butt welding. Among them, by butt welding, the weld seams generated by the welding between adjacent two welded pipes 1 can be reduced, so that the risk of fatigue failure at the weld seams caused by too many weld seams can be reduced, and the weight generated by too many weld seams can be reduced.

[0053] In a specific example, connection portions 15 are formed at the front ends of the left longitudinal beam 30 and the right longitudinal beam 40. The connection portions 15 are formed in a gradually expanding trumpet shape in the direction from the rear to the front. The front ends of the connection portions 15 are butt welded to the front cross member 10 and are formed with avoidance notches 16 that fit the outer peripheral surface of the front cross member 10. A second weld seam 2 in an annular structure is formed between the avoidance notches 16 of the connection portions 15 and the outer peripheral surface of the front cross member 10.

[0054] According to some embodiments of the present utility model, the welded pipe 1 is an internally high-pressure formed part. Thus, by internally high-pressure forming the welded pipe 1, while meeting the shape of the welded pipe 1, the wall thickness change of the welded pipe 1 can be ensured to be uniform, so as to improve the strength of the welded pipe 1. Among them, the internally high-pressure forming can be hydraulic forming, or it can be hot gas bulging forming, etc., which is not specifically limited here.

[0055] In a specific example, the welded pipe 1 is a steel plate with or without a coating and having a yield strength in the range of 300 MPa to 550 MPa, so as to reduce the difficulty of internally high-pressure forming while ensuring strength.

[0056] According to some embodiments of the present utility model, the front cross member 10, the left longitudinal member 30 and the right longitudinal member 40 are welded pipes 1, and the rear cross member 20 is a stamping and splicing welded part. Among them, since the structure of the rear cross member 20 is relatively complex and the force is greater, therefore, the rear cross member 20 can be produced and processed by stamping and splicing welding to reduce the processing difficulty of the rear cross member 20.

[0057] Specifically, during the production and processing of the subframe structure 100;

[0058] First step, according to the design requirements and the CAE analysis results, determine the shapes, material grades, thickness distributions, and pipe sizes of each tubular beam, namely the front cross member 10, the rear cross member 20, the left longitudinal member 30, and the right longitudinal member 40.

[0059] Second step, roll the equal-thickness steel plate into a variable-thickness plate and then perform annealing treatment.

[0060] Third step, make the variable-thickness pipe by roll pressing - welding the variable-thickness steel plate, and the weld of the pipe can be annealed or not.

[0061] Fourth step, make the welded pipe 1 by stamping or internal high-pressure forming of the variable-thickness pipe, and the rear cross member 20 is formed by stamping and the parts are punched.

[0062] Fifth step, use gas shielded welding to weld and connect the front cross member 10, the rear cross member 20, the left longitudinal member 30, and the right longitudinal member 40;

[0063] Sixth step, grind, correct the welding surface, and clean.

[0064] Seventh step, electrophoresis.

[0065] Next, a vehicle according to an embodiment of the second aspect of the present utility model will be described with reference to the accompanying drawings.

[0066] The vehicle according to an embodiment of the second aspect of the present utility model includes: a subframe structure 100.

[0067] In the vehicle according to an embodiment of the second aspect of the present utility model, at least part of the front cross member 10, the rear cross member 20, the left longitudinal member 30, and the right longitudinal member 40 is a welded pipe 1, which can preferably reduce the number of welds on the subframe and the area covered by the welds, can reduce the risk of fatigue failure at the welds on the subframe structure 100, and reduce the overall weight of the subframe assembly, so as to improve the durability performance and lightweight level of the subframe structure 100.

[0068] In a specific example, the subframe structure 100 is the front subframe of the vehicle.

[0069] In the present utility model, unless otherwise clearly defined and limited, terms such as "installation", "connection", "attachment", "fixation", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the internal communication between two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0070] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0071] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present utility model, and the scope of the present utility model is defined by the claims and their equivalents.

Claims

1. A subframe structure, characterized in that, Comprising: A front cross member, a rear cross member, a left longitudinal beam, and a right longitudinal beam connected by welding, wherein at least part of the front cross member, the rear cross member, the left longitudinal beam, and the right longitudinal beam are welded pipes, a pipe cavity is provided inside the welded pipes, and the pipe cavity is formed by butt-jointing both ends of a plate-shaped profile.

2. The subframe structure according to claim 1, characterized in that, The cross-section of the pipe cavity is arc-shaped; and / or, a weld seam is provided at the butt-joint of both ends of the plate-shaped profile.

3. The subframe structure according to claim 1, characterized in that, The wall thickness of the welded pipe is different in the extending direction.

4. The subframe structure according to claim 3, characterized in that, The pipe wall of the welded pipe is a flexible rolled piece.

5. The subframe structure according to claim 3, characterized in that, In the direction from both ends of the welded pipe to the center, the wall thickness of the welded pipe decreases.

6. The subframe structure according to claim 5, characterized in that, The welded pipe includes a first pipe section, a second pipe section, and a third pipe section. There are two second pipe sections and two third pipe sections. The two second pipe sections are respectively connected to both ends of the first pipe section. One third pipe section is connected to one end of the second pipe section far from the first pipe section, and the other third pipe section is connected to the other end of the second pipe section far from the first pipe section. The wall thickness of the first pipe section is smaller than that of the third pipe section, and the wall thickness of the second pipe section gradually decreases in the direction towards the first pipe section.

7. The subframe structure according to claim 6, characterized in that, The wall thickness range of the first pipe section is 2.0 mm to 3.5 mm; and / or, the length range of the first pipe section is 200 mm to 600 mm.

8. The subframe structure according to claim 6, characterized in that, The difference between the maximum wall thickness and the minimum wall thickness of the second pipe section is not greater than 2 mm, and the wall thickness change gradient range of the second pipe section is 1:50 to 1:200; and / or, the length range of the second pipe section is 50 mm to 200 mm.

9. The subframe structure according to claim 6, characterized in that, The wall thickness range of the third pipe section is 1.8 mm to 4.0 mm; and / or, the length range of the third pipe section is 150 mm to 500 mm.

10. The subframe structure according to claim 1, characterized in that, The weld seam of the welded pipe is located on one side of the welded pipe in the first direction, and the first direction is perpendicular to the up-down direction and perpendicular to the extending direction of the welded pipe.

11. The subframe structure according to claim 10, characterized in that, The weld seam of the welded pipe is arranged adjacent to the lower end of the welded pipe.

12. The subframe structure according to claim 1, wherein Adjacent two welded pipes are connected by butt welding.

13. The subframe structure according to claim 1, characterized in that, The welded pipe is an internally high-pressure formed part; and / or, the front cross member, the left longitudinal beam, and the right longitudinal beam are welded pipes, and the rear cross member is a stamping and splicing welded part.

14. A vehicle, characterized in that, Comprising: The subframe structure according to any one of claims 1 - 13.

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