Extensible auxiliary frame structure, vehicle and working method

Abstract

The invention discloses an extensible auxiliary frame structure, a vehicle and an installation method, relates to the technical field of automobiles, solves the problem that an auxiliary frame is poor in motor size compatibility in the prior art, and has the beneficial effects that the space is reasonably utilized, and more motors can be compatible. Comprising an auxiliary frame body, the auxiliary frame body forms a frame structure through cross beams and longitudinal beams, the longitudinal beams of the auxiliary frame body are higher than the cross beams, the parts, higher than the cross beams, of the longitudinal beams are provided with positioning parts, at least one detachable cross beam can be installed on the auxiliary frame body through the positioning parts at the positions of the longitudinal beams, and the detachable cross beam is provided with a suspension support. The auxiliary frame body is provided with a suspension installation part, suspension installation of the motor is achieved through the suspension installation part and the suspension support, the detachable cross beam is located above one cross beam, the detachable cross beam and the cross beam below the detachable cross beam are arranged in a staggered mode, and the detachable cross beam has multiple choices.

Description

Technical Field

[0001] The present invention relates to the technical field of automobiles, especially electric vehicles, and particularly to an expandable subframe structure, a vehicle, and a working method. Background Art

[0002] The statements in this part merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] The subframe can be regarded as the skeleton of the front and rear axles and is an integral part of the front and rear axles. The subframe is not a complete vehicle frame but only a bracket that supports the front and rear axles and the suspension, enabling the axles and suspension to be connected to the "main frame" through it.

[0004] With the development of the times, the progress of technology, and the increasingly stringent environmental protection requirements, range-extended electric vehicles (REEV), plug-in hybrid electric vehicles (PHEV), and battery electric vehicles (BEV) are becoming the mainstream in the automotive industry. To reduce the overall vehicle cost or meet the needs of various configuration gradients, major vehicle manufacturers often install multiple motors on the same platform or the same vehicle model. The differences in the motors will inevitably lead to differences in the boundary dimensions, and the differences in the boundary dimensions affect the boundary of the subframe through the suspension system, which affects the platform development of the subframe. That is to say, the existing subframe has poor compatibility with the motor size and torque, and the subframe is a fixed structure. In some solutions, holes are directly drilled in the subframe to install the motor, which makes the subframe unable to simultaneously meet the NVH (noise, vibration, and harshness) performance requirements such as the dynamic stiffness of the suspension mounting points and the constrained mode, further affecting the vehicle platformization, generalization, and R & D cost investment.

[0005] In the prior art, there are also solutions for improving the subframe for motor installation. For example, Chinese Patent Application CN202420873442.6, published on April 25, 2024, discloses a platformized front subframe for a suspension power system. The subframe is provided with a front subframe crossbeam, and the front subframe crossbeam is provided with a suspension mounting position for installing the motor. However, the front subframe crossbeam is fixedly connected to the subframe body and serves as one of the crossbeams of the subframe body, which will affect the setting of the structural members originally installed at the subframe body and there is a problem of insufficient space utilization. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an expandable subframe structure to provide a solution for the platform development of the subframe.

[0007] To achieve the above purpose, the present invention is implemented through the following technical solutions:

[0008] An expandable subframe structure includes a subframe body. The subframe body is formed into a frame structure by cross beams and longitudinal beams. The longitudinal beams of the subframe body are arranged higher than the cross beams. Positioning parts are arranged on the parts of the longitudinal beams higher than the cross beams. At least one split cross beam is installed on the subframe body through the positioning parts at both sides of the longitudinal beams. The split cross beam is provided with a suspension bracket, and the subframe body is provided with a suspension mounting part. The suspension mounting of the motor is realized through the suspension mounting part and the suspension bracket. The split cross beam is located above one of the cross beams, and the split cross beam is arranged offset from the cross beam below it.

[0009] For an expandable subframe structure as described above, to ensure versatility, there are various choices for the split cross beam. The positions of the suspension brackets, the number of suspension brackets, or the structures of the suspension brackets at different split cross beams are different. Select a suitable split cross beam according to the motor to be installed.

[0010] For an expandable subframe structure as described above, considering that the sizes of motors are different, to further meet the requirements and maximize the platformization of the subframe structure, the split cross beam is concave towards the center of the subframe body to install a motor with a relatively small size;

[0011] Or, the split cross beam is convex away from the center of the subframe body to install a motor with a relatively large size. The outwardly convex split cross beam ensures the space between the subframe body and the split cross beam, which can be used to install a motor with a relatively large size.

[0012] For an expandable subframe structure as described above, one end of the longitudinal beam is set as an L shape. The horizontal section of the L-shaped end of the longitudinal beam is connected to the cross beam, and the vertical section of the L-shaped end of the longitudinal beam is provided with the positioning part. In this way, the space is fully utilized, and the split cross beam is located above one of the cross beams on one side of the subframe body, without interfering with the installation of structural components at the cross beam.

[0013] For an expandable subframe structure as described above, the positioning part is a positioning boss. A first opening is arranged at the positioning part. Second openings are respectively arranged at both ends of the split cross beam. Fasteners pass through the second openings and the first opening to fasten the split cross beam to the subframe body.

[0014] For an expandable subframe structure as described above, to avoid interference between the original components at the subframe and the split cross beam, the distance between the split cross beam and the center of the subframe body is less than the distance between the cross beam below it and the center of the subframe body;

[0015] The suspension mounting part is arranged at one of the cross beams on the subframe body away from the split cross beam, so as to ensure the stable support of the motor.

[0016] An extensible subframe structure as described above. To ensure the structural strength of the split beam, the height of the middle part of the split beam is greater than that of its two sides. The split beam is provided with at least one mounting hole for the suspension bushing, and the suspension bushing is installed in the mounting hole for the suspension bushing. The suspension bracket is fixedly connected to the suspension bushing;

[0017] To control the weight of the split beam, the inside of the split beam is hollow. The split beam is provided with reinforcing ribs on the side of the mounting hole for the suspension bushing, and the outside of the split beam is coated with a protective layer.

[0018] An extensible subframe structure as described above. The side of the suspension bracket away from the split beam is arc-shaped, and at least three third openings are provided on the arc side of the suspension bracket, and the distance between adjacent two third openings is set at intervals.

[0019] An extensible subframe structure as described above. The subframe body includes a first cross beam, and both ends of the first cross beam are respectively connected to a first longitudinal beam and a second longitudinal beam. The ends of the first longitudinal beam and the second longitudinal beam away from the first cross beam are connected to a second cross beam. The first longitudinal beam and the second longitudinal beam are provided with positioning parts, the second cross beam is arranged lower than the positioning parts, the height of the middle part of the first longitudinal beam and the second longitudinal beam is greater than that of their two sides, and a third cross beam is further connected between the bottom sides of the first longitudinal beam and the second longitudinal beam.

[0020] An extensible subframe structure as described above. The first cross beam is provided with the suspension mounting part, and the suspension mounting part includes a first mounting bracket and a second mounting bracket arranged oppositely. The first mounting bracket is provided with a mounting through hole, and the second mounting bracket is provided with a mounting threaded hole.

[0021] In a second aspect, the present invention also provides a vehicle, which adopts the extensible subframe structure as described above.

[0022] In a third aspect, the present invention also provides an installation method for an extensible subframe structure, which includes the following contents:

[0023] Positioning parts are arranged at the longitudinal beams during the manufacturing process of the subframe body;

[0024] The split beam is installed through the positioning parts at the longitudinal beams, and after the split beam is installed, it is located above the cross beams on the same side;

[0025] The suspension installation of the motor is realized through the suspension mounting part and the suspension bracket at the split beam.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1) In the subframe structure of the present invention, the subframe body is provided with positioning parts, and the detachable crossbeam can be installed at the subframe body through the positioning parts. The detachable crossbeam provides a mounting bracket for the suspension, and the subframe body is provided with a suspension mounting part. In this way, the subframe body can be placed around the original motor, and then the upper space of the subframe body is used to stably install the suspended motor, meeting the requirements of mounting multiple motors with different sizes or wheel-end torques on the same platform or the same vehicle model, improving the platformization and generalization degree of the subframe, reducing the R & D cost investment. The detachable crossbeam is placed above one side crossbeam to avoid interference with the installation of components on the crossbeam.

[0028] 2) In the present invention, the detachable crossbeam can be installed on the subframe body and provides a suspension bracket for connecting with the motor. There is no need to drill holes in the subframe body. The additional motor is stably installed through the cooperation of the suspension bracket and the suspension mounting part, maximizing the dynamic stiffness and mode at the active end of the vehicle, improving the vibration isolation performance at the motor, and thus enhancing the overall vehicle NVH performance.

[0029] 3) In the present invention, the detachable crossbeam can be concave towards the center of the subframe body or convex towards the outside of the subframe body. There are various options for the detachable crossbeam, and it is possible to select a suitable detachable crossbeam according to the motor to be installed, achieving compatibility with different-sized motors with a relatively small cost investment, making the subframe highly generalized and platformized, and significantly reducing the R & D investment in the subframe, such as mold and labor costs. The selection of the concave or convex detachable crossbeam, combined with the change in the number of suspension brackets, meets the requirements of motors with large and small wheel-end torques while taking cost into account.

[0030] 4) In the present invention, by utilizing the structural characteristics of the longitudinal beam in the subframe body, the positioning parts are reasonably set, effectively using the upper space of the subframe body to install the suspension of the additional motor, without affecting the structural stiffness of the original subframe body, and also avoiding interference with the structural components at the crossbeam of the subframe body. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0032] Figure 1 is a schematic diagram of an expandable subframe structure according to one or more embodiments of the present invention Figure 1 .

[0033] Figure 2 is a schematic diagram of an expandable subframe structure according to one or more embodiments of the present invention Figure 2 .

[0034] Figure 3is the front view of an extensible subframe structure according to one or more embodiments of the present invention.

[0035] Figure 4 is the front view of a detachable crossbeam in an extensible subframe structure according to one or more embodiments of the present invention.

[0036] Figure 5 is a schematic diagram of a mounting bracket in an extensible subframe structure according to one or more embodiments of the present invention.

[0037] Figure 6 is a schematic view of the mounting bracket mounted on the detachable crossbeam in an extensible subframe structure according to one or more embodiments of the present invention Figure 1 .

[0038] Figure 7 is a schematic view of the mounting bracket mounted on the detachable crossbeam in an extensible subframe structure according to one or more embodiments of the present invention Figure 2 .

[0039] In the figure: The distances or dimensions between each part are exaggerated for showing the positions of each part, and the schematic diagram is only for illustration.

[0040] Wherein: 1. Detachable crossbeam, 2. Mounting bracket, 3. Mounting bushing, 4. Subframe body, 5. Mounting part, 6. First bolt, 7. Second bolt;

[0041] 1-1. Reinforcing rib, 1-2. Mounting hole for mounting bushing, 1-3. Second opening;

[0042] 2-1. Fourth opening, 2-2. Third opening;

[0043] 4-1. Positioning part, 4-2. First crossbeam, 4-3. First longitudinal beam, 4-4. Second longitudinal beam, 4-5. Second crossbeam, 4-6. Third crossbeam;

[0044] 5-1. First mounting bracket, 5-2. Second mounting bracket. Detailed implementation manners

[0045] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the present invention clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof;

[0047] As introduced in the background art, there is a problem of poor compatibility of subframes in the prior art. To solve the above technical problems, the present invention proposes an expandable subframe structure.

[0048] Embodiment 1

[0049] In a typical embodiment of the present invention, referring to Figure 1 、 Figure 2 and Figure 3 shown, an expandable subframe structure includes a subframe body 4. The subframe body 4 is formed by cross beams and longitudinal beams to form a frame structure. The longitudinal beams of the subframe body 4 are higher than the cross beams. Positioning parts are provided on the parts where the longitudinal beams are higher than the cross beams. At least one split cross beam 1 is installed at the subframe body through the positioning parts 4-1 at both sides of the longitudinal beams. The split cross beam 1 is provided with a suspension bracket 2, and the subframe body 4 is provided with a suspension mounting part 5. The suspension mounting of the motor is realized through the suspension mounting part 5 and the suspension bracket 2. The split cross beam is located above one of the cross beams, and the split cross beam is arranged in a staggered manner with the cross beam below it.

[0050] Specifically, the subframe body 4 is provided with two suspension mounting parts 5, and both of the two suspension mounting parts 5 are installed at a cross beam of the subframe body 4 away from the split cross beam 1, so as to ensure the stable support of the motor.

[0051] Referring to Figure 2 shown, the subframe body 4 includes a first cross beam 4-2. The two ends of the first cross beam 4-2 are respectively connected to a first longitudinal beam 4-3 and a second longitudinal beam 4-4. The ends of the first longitudinal beam 4-3 and the second longitudinal beam 4-4 away from the first cross beam are connected to a second cross beam. Positioning parts are provided at the ends of the first longitudinal beam 4-3 and the second longitudinal beam 4-4 away from the first cross beam. The second cross beam 4-5 is lower than the positioning parts. The second cross beam 4-5 is lower than the first cross beam. The height in the middle of the first longitudinal beam 4-3 and the second longitudinal beam 4-4 is greater than the height on both sides of them. A third cross beam 4-6 is also connected between the bottom sides of the first longitudinal beam and the second longitudinal beam;

[0052] In this embodiment, two suspension mounting parts 5 are provided on the first cross beam 4-2, and the distance between the two suspension mounting parts 5 is set at intervals. The suspension mounting part 5 includes a first mounting bracket 5-1 and a second mounting bracket 5-2 which are oppositely arranged. The first mounting bracket 5-1 is provided with a mounting through hole, and the second mounting bracket 5-2 is provided with a mounting threaded hole. The first mounting bracket is a vertical bracket, and the vertical bracket is perpendicular to the first cross beam. The second mounting bracket 5-2 protrudes from the first cross beam. The first mounting bracket 5-1 and the second mounting bracket 5-2 have a set height, and the thickness of the second mounting bracket is greater than that of the first mounting bracket. The second mounting bracket is integrally connected to the first longitudinal beam or the second longitudinal beam to enhance the overall structural stiffness.

[0053] It is easily understood that in order to avoid interference between the original components at the subframe and the split cross beam 1, the distance between the split cross beam 1 and the center of the subframe body 4 is less than the distance between the second cross beam 4-5 below it and the center of the subframe body 4, and the length of the second cross beam 4-5 below the split cross beam is greater than the length of the split cross beam.

[0054] It should be noted that one end of the first longitudinal beam 4-3 and the second longitudinal beam 4-4 is set in an L shape. The horizontal section of the L-shaped end of the longitudinal beam is connected to the cross beam. The vertical section of the L-shaped end of the first longitudinal beam and the second longitudinal beam is provided with a positioning part, and the positioning part protrudes in the direction away from the center of the subframe body 4. The distance between the positioning part and the second cross beam is set at intervals. In this way, the space is fully utilized, so that the split cross beam 1 is located above the second cross beam 4-5 of the subframe body and will not interfere with the installation of the structural parts at the second cross beam.

[0055] Specifically, the positioning part 4-1 is a positioning boss. A first opening is provided at the positioning part 4-1, and the first opening is a threaded hole. Second openings 1-3 are respectively provided at both ends of the split cross beam. The second openings are through holes. The length of the split cross beam 1 is adapted to the distance between the two positioning parts. Fasteners such as the first bolt 6 pass through the second opening and the first opening to fasten the split cross beam 1 to the subframe body 4.

[0056] Considering that the sizes of the motors are different, in order to further meet the requirements and maximize the platformization of the subframe structure, the split cross beam 1 is concave towards the center of the subframe body 4 to install a motor with a relatively small size through the split cross beam and the suspension mounting part;

[0057] Or, as shown in Figure 6 shown, the split cross beam 1 protrudes outward away from the center of the subframe body 4 to install a motor with a relatively large size. The outward protruding split cross beam 1 ensures the space between the subframe body and the split cross beam 1. At this time, the middle section of the split cross beam 1 is a connecting plate, and the connecting plate is connected to the connecting ear through an arc section. Second openings 1-3 are provided at the connecting ear. In this way, the split cross beam and the suspension mounting part can be used to install a motor with a relatively large size.

[0058] To ensure the structural strength of the split crossbeam, the height in the middle of the split crossbeam 1 is greater than the height on both sides thereof, that is, the height at the connecting ear is less than the height at the connecting plate. Refer to Figure 4 As shown, the split crossbeam is provided with at least one mounting hole 1-2 for the suspension bushing. The suspension bushing is mounted in the mounting hole 1-2 for the suspension bushing. One end of the suspension bracket 2 is provided with a fourth opening 2-1, and the fourth opening is a threaded hole. Refer to Figure 7 As shown, the second bolt 7 passes through the suspension bushing 2 and is tightly connected to the fourth opening 2-1; the mounting hole 1-2 for the suspension bushing is provided at the connecting plate of the split crossbeam, and the suspension bushing 3 is placed into the mounting hole 1-2 for the suspension bushing by press-fitting. In this way, the split crossbeam with the press-fitted suspension bushing 3 is connected to the subframe body by bolts, which is convenient for expansion. At the same time, the split crossbeam with the suspension bushing reduces the difficulty and cost of replacement after the suspension bushing is damaged.

[0059] To control the weight of the split crossbeam 1, the split crossbeam 1 is hollow inside. The split crossbeam is provided with reinforcing ribs 1-1 at the side of the mounting hole for the suspension bushing. The reinforcing ribs 1-1 can be cross-shaped reinforcing ribs to ensure sufficient strength and dynamic stiffness under the structure of the large-size suspension bushing. The reinforcing ribs 1-1 are provided on both sides of the mounting hole 1-2 for the suspension bushing. The outside of the split crossbeam 1 is coated with a protective layer, and the protective layer can be welded to the split crossbeam.

[0060] To ensure versatility, it is easy to understand that the split crossbeam 1 has various options. The positions of the suspension brackets at different split crossbeams are different, that is, the suspension bracket 2 can be arranged in the middle position or on both sides of the split crossbeam, or the number of suspension brackets at different split crossbeams is different, that is, the number of suspension brackets 2 can be one or two. The number of suspension brackets can be adjusted in combination with the torque magnitude or performance requirements of the electric drive wheel end to meet the requirements of the durability of the suspension support and the anti-torsion of the large-torque motor; or the structures of the suspension brackets 2 of different split crossbeams are different, that is, the suspension bracket and the motor mounting hole, that is, the third opening, can be designed as three or four in combination with the existing bolt slip check results. Generally, a bolt with a larger diameter such as an M14 bolt is selected for a single suspension bracket, and 2×M12 bolts are selected for a double suspension bracket;

[0061] Refer to Figure 5 As shown, the suspension bracket 2 is integrally in the shape of a trapezoidal block. A cylindrical part is provided on the shorter side of the suspension bracket. The fourth opening 2-2 is provided at the cylindrical part. The side of the suspension bracket away from the split crossbeam is arc-shaped. At least three third openings 2-2 are provided on the arc side of the suspension bracket 2. The central axis of the third opening 2-2 is perpendicular to the central axis of the fourth opening 2-1. The central axis of the third opening is parallel to the length direction of the split crossbeam. The distance between adjacent two third openings 2-2 is set at intervals. The size of the suspension bracket can be flexibly designed in combination with the motor boundary, further broadening the compatibility of the subframe structure with the motor size;

[0062] The subframe structure provided in this embodiment has a positioning portion 4-1 provided on the subframe body 4. The detachable crossbeam can be installed on the subframe body through the positioning portion. The detachable crossbeam 1 provides a mounting bracket 2, and the subframe body is provided with a mounting portion for the mount. In this way, the subframe body can be placed around the original motor, and then the upper space of the subframe body is used to achieve stable installation of the suspended motor, which can maximize the dynamic stiffness and mode of the vehicle's driving end, improve the vibration isolation performance at the motor, and further improve the overall vehicle NVH performance. It provides a subframe structure with high generalization and high platformization, and a design solution for a subframe structure that can accommodate motors with a large size span. There are no strict requirements for the material of the detachable crossbeam, the number of detachable crossbeams, the specific position of the detachable crossbeams, the number of specific mounting points of the suspension bushings, and the number and position of the mounting points between the suspension brackets and the mounting portion for the mount.

[0063] Embodiment II

[0064] This embodiment provides a vehicle that adopts the expandable subframe structure described in Embodiment I.

[0065] Embodiment III

[0066] This embodiment provides an installation method for an expandable subframe structure, including the following content:

[0067] During the manufacturing process of the subframe body 4, a positioning portion 4-1 is provided at the longitudinal beam.

[0068] The detachable crossbeam 1 is installed through the positioning portions at the two longitudinal beams. After the detachable crossbeam 1 is installed, it is located above the second crossbeam 4-5.

[0069] Select a suitable detachable crossbeam according to the motor to be installed. Some motors are located at the center of the subframe body. The suspension installation of the additional motor is realized through the suspension installation portion and the suspension bracket at the detachable crossbeam. In this way, stable installation of the additional motor by the subframe structure is achieved.

[0070] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An expandable subframe structure, characterized in that: The vehicle comprises a sub-frame body, which is formed into a frame structure by a cross beam and a longitudinal beam. The longitudinal beam of the sub-frame body is arranged higher than the cross beam, and a positioning part is arranged on the part of the longitudinal beam higher than the cross beam. At least one detachable cross beam is installed on the sub-frame body through the positioning parts on the longitudinal beams on both sides. The detachable cross beam is provided with a suspension bracket, and the sub-frame body is provided with a suspension mounting part. The suspension mounting part and the suspension bracket are used to realize the suspension installation of the motor. The detachable cross beam is located above one of the cross beams, and the detachable cross beam is staggered with the cross beam below it.

2. The expandable subframe structure according to claim 1, characterized in that: The detachable crossbeam has multiple options. The positions of the suspension brackets at different detachable crossbeams are different, or the numbers of the suspension brackets are different, or the structures of the suspension brackets are different. A suitable detachable crossbeam is selected according to the motor to be installed.

3. The expandable subframe structure according to claim 1, characterized in that: The detachable cross beam is recessed toward the center of the sub-frame body to mount a relatively small motor; Alternatively, the detachable cross beam protrudes outward away from the center of the sub-frame body to install a relatively large motor.

4. The expandable subframe structure according to claim 1, characterized in that: One end of the longitudinal beam is arranged in an L shape, the horizontal section of the L-shaped end of the longitudinal beam is connected to the cross beam, and the vertical section of the L-shaped end of the longitudinal beam is arranged with the positioning portion.

5. The expandable subframe structure according to claim 1, characterized in that: The positioning portion is a positioning boss, a first opening is arranged at the positioning portion, second openings are arranged at both ends of the detachable cross beam respectively, and a fastener passes through the second opening and the first opening to fasten the detachable cross beam to the auxiliary frame body.

6. The expandable subframe structure according to claim 1, characterized in that: The distance between the detachable cross beam and the center of the sub-frame body is smaller than the distance between the cross beam below it and the center of the sub-frame body; The suspension mounting portion is arranged on a cross beam of the auxiliary frame body away from the detachable cross beam.

7. The expandable subframe structure according to claim 1, characterized in that: The height of the middle part of the detachable cross beam is greater than the height of the two sides thereof, the detachable cross beam is provided with at least one suspension bushing installation hole, the suspension bushing is installed in the suspension bushing installation hole, and the suspension bracket is fastened to the suspension bushing; The interior of the detachable cross beam is hollow, reinforcing ribs are arranged on the side of the suspension bushing installation hole of the detachable cross beam, and the outer side of the detachable cross beam is covered with a protective layer.

8. The expandable subframe structure according to claim 1, characterized in that: The side of the suspension bracket away from the detachable cross beam is arc-shaped, and at least three third openings are arranged on the arc-shaped side of the suspension bracket, and a distance is set between two adjacent third openings.

9. The expandable subframe structure according to claim 1, characterized in that: The subframe body includes a first cross beam, the two ends of the first cross beam are respectively connected to the first longitudinal beam and the second longitudinal beam, the ends of the first longitudinal beam and the second longitudinal beam away from the first cross beam are connected to the second cross beam, the first longitudinal beam and the second longitudinal beam are provided with positioning parts, the second cross beam is arranged lower than the positioning parts, the height of the middle part of the first longitudinal beam and the second longitudinal beam is greater than the height of the two sides thereof, and a third cross beam is also connected between the bottom sides of the first longitudinal beam and the second longitudinal beam.

10. The expandable subframe structure according to claim 9, characterized in that: The first cross beam is provided with the suspension mounting portion, and the suspension mounting portion includes a first mounting frame and a second mounting frame which are arranged opposite to each other, the first mounting frame is provided with a through hole, and the second mounting frame is provided with a threaded hole.

11. A vehicle, characterized in that: An expandable subframe structure according to any one of claims 1 to 10 is adopted.

12. A method for installing an expandable subframe structure according to any one of claims 1 to 10, characterized in that: It includes the following: During the manufacturing process of the subframe body, a positioning portion is provided at the longitudinal beam; The detachable cross beam is installed through the positioning part at the longitudinal beam, and the detachable cross beam is located above the cross beam on the same side after installation; The suspension installation of the motor is achieved through the suspension installation part and the suspension bracket at the detachable crossbeam.

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