A front subframe for automobiles

Abstract

This invention provides a front subframe for automobiles, relating to the field of new energy vehicle manufacturing technology. It includes a front crossbeam, a left longitudinal beam, a right longitudinal beam, and a rear crossbeam. The rear ends of the left and right longitudinal beams are connected via the rear crossbeam, and their front ends are connected via the front crossbeam. A left energy-absorbing box mounting bracket is installed at the front end of the left longitudinal beam, and a right energy-absorbing box mounting bracket is installed at the front end of the right longitudinal beam. Energy-absorbing box bodies are mounted on the left and right energy-absorbing box mounting brackets. An energy-absorbing mechanism is provided within the energy-absorbing box body, including a fixed box and a first rack. One end of the first rack is connected to the fixed box via a return spring, and the other end is connected to the anti-collision beam. In this invention, after the anti-collision beam is impacted, the energy-absorbing box body has a better energy-absorbing effect than traditional energy-absorbing boxes, improving collision safety. It also reduces the probability of damage to the front subframe after a collision. When the subframe is not damaged, only the energy-absorbing box body needs to be replaced, thus reducing maintenance costs to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle manufacturing technology, and in particular to a front subframe for automobiles. Background Technology

[0002] The front subframe of a new energy vehicle is an important component of the vehicle's chassis. As the carrier of chassis components, the front subframe bears the weight of the vehicle body and provides a mounting base for components such as the suspension system and steering system, ensuring that these components can work stably and accurately. Its performance directly affects the vehicle's handling, stability, and ride comfort.

[0003] Chinese Patent CN217146150U discloses a front subframe assembly and a vehicle thereof. The front subframe assembly includes a subframe body and an energy-absorbing component. The energy-absorbing component includes a first beam, a second beam, and a third beam, with the first and second beams spaced apart and the third beam positioned between them. The first and second beams are welded to the subframe body. The energy-absorbing component also includes a first housing and a second housing, with the first housing connected to the first beam and the second housing connected to the second beam. The first and second housings are used for collision energy absorption. This patented front subframe assembly can improve the connection stability between the front subframe and the energy-absorbing structure.

[0004] The aforementioned energy-absorbing components can absorb the energy generated during a collision by deforming the first and second housings. However, the energy-absorbing components in the front subframe assembly deform after absorbing energy, resulting in poor energy absorption. The collision energy is then transferred to the subframe body through the first and second beams, causing the subframe body to deform. In this case, the entire front subframe assembly needs to be replaced, resulting in high repair costs. Summary of the Invention

[0005] This invention provides a front subframe for automobiles to solve the technical problem that in existing front subframe assemblies, the energy-absorbing components deform after absorbing energy, resulting in poor energy absorption. Consequently, collision energy is transferred to the subframe body through the first and second beams, causing deformation of the subframe body. This necessitates replacing the entire front subframe assembly, leading to high repair costs.

[0006] To solve the above-mentioned technical problems, the present invention discloses a front subframe for automobiles, comprising: a front crossbeam, a left longitudinal beam, a right longitudinal beam, and a rear crossbeam. The rear ends of the left and right longitudinal beams are connected by the rear crossbeam, and the front ends of the left and right longitudinal beams are connected by the front crossbeam. A left energy-absorbing box mounting bracket is provided at the front end of the left longitudinal beam, and a right energy-absorbing box mounting bracket is provided at the front end of the right longitudinal beam. Energy-absorbing box bodies are mounted on the left and right energy-absorbing box mounting brackets. The rear sides of the left and right energy-absorbing box bodies are respectively connected to the left and right energy-absorbing box mounting brackets by bolts. A crash beam is provided in front of the energy-absorbing box body. An energy-absorbing mechanism is provided inside the energy-absorbing box body. The energy-absorbing mechanism includes a fixed box, the outer wall of which is fixedly connected to the inner wall of the energy-absorbing box body. A first rack is provided inside the energy-absorbing box body. One end of the first rack near the fixed box is connected to the fixed box by a return spring, and the other end of the first rack extends to the outside of the energy-absorbing box body and is connected to the crash beam.

[0007] Preferably, a left control arm mounting bracket is provided on the side of the left longitudinal beam away from the right longitudinal beam, and the left control arm mounting bracket is located near the middle of the left longitudinal beam. A left steering gear mounting bracket is provided on the left longitudinal beam. A right control arm mounting bracket is provided on the side of the right longitudinal beam away from the left longitudinal beam, and the right control arm mounting bracket is located near the middle of the right longitudinal beam. A right steering gear mounting bracket is provided on the right longitudinal beam. A left suspension mounting bracket and a right suspension mounting bracket are respectively provided on the front side of the rear crossbeam. A rear steering gear mounting bracket is provided on the rear crossbeam, and one side of the rear steering gear mounting bracket is connected to the left suspension mounting bracket.

[0008] Preferably, the left longitudinal beam includes a left longitudinal beam upper plate and a left longitudinal beam lower plate. A first mounting hole is provided on the upper surface of the front end of the left longitudinal beam upper plate. The first mounting hole penetrates the left longitudinal beam lower plate, and a first mounting sleeve is provided in the first mounting hole.

[0009] Preferably, a first groove is provided on the upper surface of the left longitudinal beam, the first groove is located behind the first mounting hole, a fifth mounting hole and a sixth mounting hole are provided in the first groove, nuts are welded to the back of the fifth mounting hole and the sixth mounting hole, a fourth mounting hole is provided in front of the fifth mounting hole, the fourth mounting hole penetrates the lower plate of the left longitudinal beam, and a sixth mounting sleeve is provided in the fourth mounting hole.

[0010] Preferably, a second groove is provided on the upper surface of the left longitudinal beam, the second groove is located behind the first groove, the left swing arm mounting bracket is provided outside the second groove, and one side of the left swing arm mounting bracket overlaps the plane of the second groove.

[0011] Preferably, a steering gear left-side mounting bracket is provided on the upper surface of the left longitudinal beam, the steering gear left-side mounting bracket is located behind the left swing arm mounting bracket, an eleventh mounting hole is provided on the steering gear left-side mounting bracket, the eleventh mounting hole penetrates the upper plate of the left longitudinal beam, a seventh mounting sleeve is provided in the eleventh mounting hole, a first inclined platform is provided on the outer wall of the seventh mounting sleeve, and a first flange threaded pipe is provided on the top wall of the upper plate of the left longitudinal beam, the first flange threaded pipe is located directly below the seventh mounting sleeve.

[0012] Preferably, the upper surface of the left longitudinal beam is provided with a seventh mounting hole, an eighth mounting hole, a ninth mounting hole, and a tenth mounting hole arranged sequentially from front to back. The seventh mounting hole is located behind the left mounting bracket of the steering gear. The seventh mounting hole is back-welded with a first stabilizer bar mounting nut, and the eighth mounting hole is back-welded with a second stabilizer bar mounting nut. The ninth and tenth mounting holes penetrate the lower plate of the left longitudinal beam. A fourth mounting sleeve is installed in the ninth mounting hole, and a fifth mounting sleeve is installed in the tenth mounting hole. A first reinforcing bracket is installed at the rear end of the fifth mounting sleeve. The upper and lower sides of the first reinforcing bracket are connected to the upper plate and the lower plate of the left longitudinal beam, respectively.

[0013] Preferably, a second mounting hole and a third mounting hole are provided sequentially from front to back on the upper surface of the left longitudinal beam. The second mounting hole is located behind the tenth mounting hole. Both the second and third mounting holes penetrate the lower plate of the left longitudinal beam. A second mounting sleeve is provided in the second mounting hole, and a third mounting sleeve is provided in the third mounting hole.

[0014] Preferably, the rear crossbeam includes an upper rear crossbeam plate and a lower rear crossbeam plate. A third groove is provided on the upper surface of the upper rear crossbeam plate, a fourth groove is provided on the side of the upper rear crossbeam plate near the front crossbeam, a fifth groove is provided on the side of the lower rear crossbeam plate near the front crossbeam, and a sixth groove is provided on the lower surface of the lower rear crossbeam plate.

[0015] Preferably, a twelfth mounting hole is provided on the rear mounting bracket of the steering gear, the twelfth mounting hole penetrates the upper plate of the rear crossbeam, an eighth mounting sleeve is provided in the twelfth mounting hole, a second inclined platform is provided on the outer wall of the eighth mounting sleeve, and a second flange threaded pipe is provided on the top wall of the upper plate of the rear crossbeam, the second flange threaded pipe is located directly below the eighth mounting sleeve.

[0016] The technical solution of the present invention has the following advantages: The present invention provides a front subframe for automobiles, relating to the field of new energy vehicle manufacturing technology, including a front crossbeam, a left longitudinal beam, a right longitudinal beam, and a rear crossbeam. The rear ends of the left and right longitudinal beams are connected by the rear crossbeam, and the front ends of the left and right longitudinal beams are connected by the front crossbeam. A left energy-absorbing box mounting bracket is provided at the front end of the left longitudinal beam, and a right energy-absorbing box mounting bracket is provided at the front end of the right longitudinal beam. Energy-absorbing box bodies are mounted on the left and right energy-absorbing box mounting brackets. The rear sides of the left and right energy-absorbing box bodies are respectively connected to the left and right energy-absorbing box mounting brackets by bolts. A crash beam is provided in front of the energy-absorbing box body. An energy-absorbing mechanism is provided inside the energy-absorbing box body. The energy-absorbing mechanism includes a fixed box, the outer wall of which is fixedly connected to the inner wall of the energy-absorbing box body. A first rack is provided inside the energy-absorbing box body. One end of the first rack near the fixed box is connected to the fixed box by a return spring, and the other end of the first rack extends to the outside of the energy-absorbing box body and is connected to the crash beam. In this invention, after the anti-collision beam is impacted, the energy-absorbing box body has a better energy absorption effect than the traditional energy-absorbing box, thus improving collision safety. At the same time, it reduces the probability of damage to the front subframe after a collision. When the subframe is not damaged, only the energy-absorbing box body needs to be replaced, which reduces maintenance costs to a certain extent.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the means particularly pointed out in the written description and the accompanying drawings.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of the front subframe structure in this invention;

[0021] Figure 2 This is a schematic diagram of the left longitudinal beam structure of the front subframe in this invention;

[0022] Figure 3 This is a schematic diagram of the internal structure of the left longitudinal beam of the front subframe in this invention;

[0023] Figure 4 This is a schematic diagram of the rear crossbeam structure of the front subframe in this invention;

[0024] Figure 5 This is a schematic diagram of the left-side mounting bracket structure for the steering gear on the front subframe in this invention;

[0025] Figure 6 This is a schematic diagram of the rear mounting bracket structure of the front subframe steering gear in this invention;

[0026] Figure 7 This is a schematic diagram of the energy-absorbing box body in this invention;

[0027] Figure 8 This is a schematic diagram of the internal structure of the energy-absorbing box body in this invention;

[0028] Figure 9 For the present invention Figure 8 Enlarged view of the structure at point A in the middle.

[0029] In the diagram: 1. Front crossbeam; 2. Left longitudinal beam; 21. Upper plate of left longitudinal beam; 22. Lower plate of left longitudinal beam; 211. First groove; 212. Second groove; 2101. First mounting hole; 2102. Second mounting hole; 2103. Third mounting hole; 2104. Fourth mounting hole; 2105. Fifth mounting hole; 2106. Sixth mounting hole; 2107. Seventh mounting hole; 2108. Eighth mounting hole; 2109. Ninth mounting hole; 2110. Tenth mounting hole; 2111. First mounting sleeve; 2112. Second... 2113, Third mounting sleeve; 2114, Fourth mounting sleeve; 2115, Fifth mounting sleeve; 2116, Sixth mounting sleeve; 2117, First reinforcing bracket; 2118, First stabilizer bar mounting nut; 2119, Second stabilizer bar mounting nut; 3, Right longitudinal beam; 4, Rear crossbeam; 41, Rear crossbeam upper plate; 42, Rear crossbeam lower plate; 411, Third groove; 412, Fourth groove; 413, Fifth groove; 414, Sixth groove; 5, Left swing arm mounting bracket; 6, Right swing arm mounting bracket; 7. Left suspension mounting bracket; 8. Right suspension mounting bracket; 9. Right side steering gear mounting bracket; 10. Left side steering gear mounting bracket; 101. Seventh mounting sleeve; 102. First flange threaded pipe; 1001. Eleventh mounting hole; 11. Rear side steering gear mounting bracket; 111. Eighth mounting sleeve; 112. Second flange threaded pipe; 1101. Twelfth mounting hole; 12. Left energy-absorbing box mounting bracket; 13. Right energy-absorbing box mounting bracket; 1201. Energy-absorbing box body; 1202. Bolt; 1203. Anti-collision device. 1204. Beam; 1205. Fixed box; 1206. Sliding hole; 1207. Drive column; 1208. Mounting bracket; 1209. Buffer spring; 1200. Sliding rod; 1210. First gear; 1211. First rack; 1212. Second rack; 1213. Return spring; 1214. First piston plate; 1215. Pressure pipe; 1216. Connecting pipe; 1217. Second piston plate; 1218. Push rod; 1219. Third rack; 1220. Second gear; 1221. Push plate; 1222. Sleeve head. Detailed Implementation

[0030] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0031] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0032] Example 1

[0033] This invention provides a front subframe for automobiles, such as... Figure 1 , Figure 7 As shown, it includes: a front crossbeam 1, a left longitudinal beam 2, a right longitudinal beam 3, and a rear crossbeam 4. The rear ends of the left longitudinal beam 2 and the right longitudinal beam 3 are connected by the rear crossbeam 4. A first connecting end with a first opening is provided on the front end of the left longitudinal beam 2 near the right longitudinal beam 3. A second connecting end with a second opening is provided on the front end of the right longitudinal beam 3 near the left longitudinal beam 2. One end of the front crossbeam 1 is connected to the left longitudinal beam 2 through the first opening, and the other end of the front crossbeam 1 is connected to the right longitudinal beam 3 through the second opening. A left energy-absorbing box mounting bracket 12 is provided on the front end of the left longitudinal beam 2, and a right energy-absorbing box mounting bracket 13 is provided on the front end of the right longitudinal beam 3. Energy-absorbing box bodies 1201 are mounted on the left energy-absorbing box mounting bracket 12 and the right energy-absorbing box mounting bracket 13. The rear sides of the left and right energy-absorbing box bodies 1201 are respectively connected to the left energy-absorbing box mounting bracket 12 and the right energy-absorbing box mounting bracket 13 by bolts 1202. A crash beam 1203 is provided in front of the energy-absorbing box body 1201. An energy-absorbing mechanism is provided inside the energy-absorbing box body 1201. The energy-absorbing mechanism includes a fixed box 1204. The outer wall of the fixed box 1204 is fixedly connected to the inner wall of the energy-absorbing box body 1201. A first rack 1211 is provided inside the energy-absorbing box body 1201. One end of the first rack 1211 near the fixed box 1204 is connected to the fixed box 1204 by a return spring 1213. The other end of the first rack 1211 extends to the outside of the energy-absorbing box body 1201 and is connected to the crash beam 1203.

[0034] The working principle and beneficial effects of the above technical solution are as follows: The front subframe is composed of a frame formed by four main beams: front crossbeam 1, left longitudinal beam 2, right longitudinal beam 3, and rear crossbeam 4. One end of the front crossbeam 1 is connected to the left longitudinal beam 2 through the first opening, and the other end of the front crossbeam 1 is connected to the right longitudinal beam 3 through the second opening. This allows the front crossbeam 1 to be made into a simple square tube, reducing the investment in molds and lowering development costs. In this invention, by setting a front crossbeam 1 and a rear crossbeam 4, the number of crossbeams is reduced, achieving a lightweight design for the front subframe. This helps reduce the production cost of the front subframe. A left energy-absorbing box mounting bracket 12 is set at the front end of the left longitudinal beam 2, and a right energy-absorbing box mounting bracket 13 is set at the front end of the right longitudinal beam 3. The left and right energy-absorbing box mounting brackets 12 and 13 can optionally be back-welded with nuts and connected to the energy-absorbing box body 1201 by bolts 1202. This facilitates the repair and replacement of the subframe and energy-absorbing box body 1201 after a car collision. Furthermore, it allows the front subframe to serve as a platform extension, enabling the energy-absorbing box body 1201 to absorb collision energy, reduce the damage to the front subframe from the impact force, reduce deformation of the front subframe, extend the service life of the front subframe, and save costs. To mitigate the impact on passengers and improve overall vehicle safety, an energy-absorbing mechanism is installed within the energy-absorbing box body 1201. This mechanism further absorbs collision energy, reducing the impact force on the front subframe and effectively mitigating the impact on passengers, thus protecting their safety. Specifically, when a collision occurs at the front of the vehicle, the anti-collision beam 1203 first contacts the object, then pushes the first rack 1211 to slide towards the fixed box 1204. The return spring 1213 gradually compresses, absorbing a portion of the impact force. The energy-absorbing mechanism can handle impacts of a smaller magnitude. After the impact, under the action of the return spring 1213, the first rack 1211 slides away from the fixed box 1204, allowing the anti-collision beam 1203 to return to its original position. In this application, when the anti-collision beam 1203 is impacted, the energy absorption mechanism further absorbs the collision energy, making the energy absorption effect of the energy absorption box body significantly better than that of the traditional energy absorption box, thus improving collision safety and reducing the probability of damage to the front subframe after a collision. When the subframe is not damaged, only the energy absorption box body needs to be replaced, which reduces maintenance costs to a certain extent.

[0035] Example 2

[0036] Based on the above embodiment 1, as follows Figure 1As shown, a left control arm mounting bracket 5 is installed on the side of the left longitudinal beam 2 away from the right longitudinal beam 3. The left control arm mounting bracket 5 is located near the middle of the left longitudinal beam 2. A left steering gear mounting bracket 10 is installed on the left longitudinal beam 2. A right control arm mounting bracket 6 is installed on the side of the right longitudinal beam 3 away from the left longitudinal beam 2. The right control arm mounting bracket is located near the middle of the right longitudinal beam 3. A right steering gear mounting bracket 9 is installed on the right longitudinal beam 3. A left suspension mounting bracket 7 and a right suspension mounting bracket 8 are respectively installed on the front side of the rear crossbeam 4. A rear steering gear mounting bracket 11 is installed on the rear crossbeam 4. One side of the rear steering gear mounting bracket 11 is connected to the left suspension mounting bracket 7.

[0037] The working principle and beneficial effects of the above technical solution are as follows: A left control arm mounting bracket 5 is set on the side of the left longitudinal beam 2 away from the right longitudinal beam 3. The left control arm mounting bracket 5 is used to install the left control arm. A right control arm mounting bracket 6 is set on the side of the right longitudinal beam 3 away from the left longitudinal beam 2. The right control arm mounting bracket 6 is used to install the right control arm. A steering gear left mounting bracket 10 is set on the left longitudinal beam 2, and a steering gear right mounting bracket 9 is set on the right longitudinal beam 3, which are used to install the steering gear respectively. A suspension mounting bracket left piece 7 and a suspension mounting bracket right piece 8 are set on the front side of the rear crossbeam 4, which can be used to install suspension components.

[0038] Example 3

[0039] Based on Example 1 or 2, such as Figure 2 , Figure 3 , Figure 5 As shown, the left longitudinal beam 2 includes a left longitudinal beam upper plate 21 and a left longitudinal beam lower plate 22. A first mounting hole 2101 is provided on the upper surface of the front end of the left longitudinal beam upper plate 21. The first mounting hole 2101 penetrates the left longitudinal beam lower plate 22. A first mounting sleeve 2111 is provided in the first mounting hole 2101.

[0040] A first groove 211 is provided on the upper surface of the upper plate 21 of the left longitudinal beam. The first groove 211 is located behind the first mounting hole 2101. A fifth mounting hole 2105 and a sixth mounting hole 2106 are provided in the first groove 211. Nuts are welded to the back of the fifth mounting hole 2105 and the sixth mounting hole 2106. A fourth mounting hole 2104 is provided in front of the fifth mounting hole 2105. The fourth mounting hole 2104 penetrates the lower plate 22 of the left longitudinal beam. A sixth mounting sleeve 2116 is provided in the fourth mounting hole 2104.

[0041] A second groove 212 is provided on the upper surface of the upper plate 21 of the left longitudinal beam. The second groove 212 is located behind the first groove 211. The left swing arm mounting bracket 5 is provided on the outside of the second groove 212. One side of the left swing arm mounting bracket 5 overlaps on the plane of the second groove 212.

[0042] A steering gear left mounting bracket 10 is provided on the upper surface of the left longitudinal beam upper plate 21. The steering gear left mounting bracket 10 is located behind the left swing arm mounting bracket 5. An eleventh mounting hole 1001 is provided on the steering gear left mounting bracket 10. The eleventh mounting hole 1001 penetrates the left longitudinal beam upper plate 21. A seventh mounting sleeve 101 is provided inside the eleventh mounting hole 1001. A first inclined platform is provided on the outer wall of the seventh mounting sleeve 101. A first flange threaded pipe 102 is provided on the top wall of the left longitudinal beam upper plate 21. The first flange threaded pipe 102 is located directly below the seventh mounting sleeve 101.

[0043] The upper surface of the upper plate 21 of the left longitudinal beam is provided with a seventh mounting hole 2107, an eighth mounting hole 2108, a ninth mounting hole 2109 and a tenth mounting hole 2110 in sequence from front to back. The seventh mounting hole 2107 is located behind the left mounting bracket 10 of the steering gear. The seventh mounting hole 2107 is back-welded with a first stabilizer bar mounting nut 2118. The eighth mounting hole 2108 is back-welded with a second stabilizer bar mounting nut 2119. The ninth mounting hole 2109 and the tenth mounting hole 2110 penetrate the lower plate 22 of the left longitudinal beam. A fourth mounting sleeve 2114 is provided in the ninth mounting hole 2109. A fifth mounting sleeve 2115 is provided in the tenth mounting hole 2110. A first reinforcing bracket 2117 is provided at the rear end of the fifth mounting sleeve 2115. The upper and lower sides of the first reinforcing bracket 2117 are connected to the upper plate 21 of the left longitudinal beam and the lower plate 22 of the left longitudinal beam, respectively.

[0044] The upper surface of the upper plate 21 of the left longitudinal beam is provided with a second mounting hole 2102 and a third mounting hole 2103 from front to back. The second mounting hole 2102 is located behind the tenth mounting hole 2110. Both the second mounting hole 2102 and the third mounting hole 2103 penetrate the lower plate 22 of the left longitudinal beam. A second mounting sleeve 2112 is provided in the second mounting hole 2102, and a third mounting sleeve 2113 is provided in the third mounting hole 2103.

[0045] The working principle and beneficial effects of the above technical solution are as follows: the first mounting sleeve 2111 is used to connect the vehicle body and improve rigidity; the fourth mounting hole 2104, the fifth mounting hole 2105 and the sixth mounting hole 2106 are used to connect the left side mount of the powertrain; the fifth mounting hole 2105 and the sixth mounting hole 2106 are back-welded with nuts; the fourth mounting hole 2104 is set in front of the fifth mounting hole 2105; the fourth mounting hole 2104 passes through the lower plate 22 of the left longitudinal beam; the sixth mounting sleeve 2116 is set inside the fourth mounting hole 2104. This achieves lightweight design while ensuring NVH performance.

[0046] A second groove 212 is provided behind the first groove 211. The second groove 212 is located directly below the drive shaft envelope. On the one hand, it avoids the drive shaft envelope, and on the other hand, it can guide the left longitudinal beam 2 to collapse during a collision, thereby satisfying the overall vehicle layout and collision performance. Furthermore, a left swing arm mounting bracket 5 is provided near the second groove 212. The left swing arm mounting bracket 5 overlaps on the plane of the second groove 212, which reduces the weight of the left swing arm mounting bracket 5 to a certain extent.

[0047] The left mounting bracket 10 of the steering gear has an eleventh mounting hole 1001, which penetrates the upper plate 21 of the left longitudinal beam. The seventh mounting sleeve 101 is provided in the middle of the hole, and the seventh mounting sleeve 101 has a first inclined platform, which helps to improve rigidity and ensure NVH performance. In addition, a first flange threaded pipe 102 is provided inside the upper plate 21 of the left longitudinal beam, which shortens the steering gear connecting bolt 1202 and further reduces the overall vehicle cost.

[0048] The seventh mounting hole 2107 and the eighth mounting hole 2108 are respectively back-welded with the first stabilizer bar mounting nut 2118 and the second stabilizer bar mounting nut 2119 for connecting the stabilizer bar; a ninth mounting hole 2109 and a tenth mounting hole 2110 are provided behind the eighth mounting hole 2108, which penetrate the lower plate 22 of the left longitudinal beam, and a fourth mounting sleeve 2114 and a fifth mounting sleeve 2115 are provided in the middle for connecting the rear bushing of the lower control arm; and a first reinforcing bracket 2117 is provided at the rear end of the fifth mounting sleeve 2115. The first reinforcing bracket 2117 is welded together with the upper plate 21 of the left longitudinal beam and the lower plate 22 of the left longitudinal beam, which improves the strength of the rear corner of the left longitudinal beam 2. Optionally, if the load of the whole vehicle is appropriate when the platform is extended, the first reinforcing bracket 2117 can be omitted to reduce the weight;

[0049] The upper plate 21 of the left longitudinal beam is provided with a second mounting hole 2102 and a third mounting hole 2103 at the rear end of the first reinforcing bracket 2117, which penetrate the lower plate 22 of the left longitudinal beam, and is provided with a second mounting sleeve 2112 and a third mounting sleeve 2113 in the middle, both of which are used to connect the vehicle body;

[0050] The specific structural design of the left longitudinal beam 2 is as described above. The specific structure and function of the right longitudinal beam 3 are exactly the same as those of the left longitudinal beam 2, so they will not be described separately. The left longitudinal beam 2 and the right longitudinal beam 3 have a total of six mounting points for the vehicle body connection. This improves the rigidity of the front subframe, solves the problem of slippage between the subframe and the vehicle body, and also solves the problem of severe collapse of the rear end of the longitudinal beam due to the height difference during a collision. At the same time, since this subframe adopts the arrangement of long longitudinal beams, generally speaking, the thermal deformation of this type of stamped parts is more serious during assembly and welding. However, this embodiment solves the deformation problem by disconnecting the weld and reducing the number of reinforcing brackets, which has good process feasibility.

[0051] Example 4

[0052] Based on Example 2 or 3, such as Figure 4 As shown, the rear crossbeam 4 includes a rear crossbeam upper plate 41 and a rear crossbeam lower plate 42. A third groove 411 is provided on the upper surface of the rear crossbeam upper plate 41, a fourth groove 412 is provided on the side of the rear crossbeam upper plate 41 near the front crossbeam 1, a fifth groove 413 is provided on the side of the rear crossbeam lower plate 42 near the front crossbeam 1, and a sixth groove 414 is provided on the lower surface of the rear crossbeam lower plate 42.

[0053] The working principle and beneficial effects of the above technical solution are as follows: The third groove 411 is used to avoid the stabilizer bar envelope, and at the same time, it works together with the sixth groove 414 to strengthen the local mode, which is beneficial to improving NVH performance; The fourth groove 412 and the fifth groove 413 provide more welding space for the left piece 7 and the right piece 8 of the suspension mounting bracket, which is beneficial to the design of the welding fixture, and also extends the weld, ensuring the strength and durability of the suspension, and ensuring the gap between the subframe and the suspension mounting bracket.

[0054] Example 5

[0055] Based on any one of Examples 2-4, such as Figure 4 , Figure 6 As shown, a twelfth mounting hole 1101 is provided on the rear mounting bracket 11 of the steering gear. The twelfth mounting hole 1101 penetrates the upper plate 41 of the rear crossbeam. An eighth mounting sleeve 111 is provided inside the twelfth mounting hole 1101. A second inclined platform is provided on the outer wall of the eighth mounting sleeve 111. A second flange threaded pipe 112 is provided on the top wall of the upper plate 41 of the rear crossbeam. The second flange threaded pipe 112 is located directly below the eighth mounting sleeve 111.

[0056] The working principle and beneficial effects of the above technical solution are as follows: The rear mounting bracket 11 of the steering gear is set above the rear crossbeam 4. The rear mounting bracket 11 of the steering gear has a twelfth mounting hole 1101 that penetrates the upper plate 41 of the rear crossbeam. An eighth mounting sleeve 111 is provided in the middle of the hole, and the eighth mounting sleeve 111 has a second inclined platform, which helps to improve rigidity and ensure NVH performance. In addition, a second flange threaded pipe 112 is provided inside the upper plate 41 of the rear crossbeam, which achieves the purpose of shortening the steering gear connecting bolts 1202 and reducing the overall vehicle cost. Furthermore, since the three mounting points of the steering gear are all set above the longitudinal beam and crossbeam of the subframe, there is a sufficiently large space between the subframe and the steering gear and steering tie rod envelope, which is conducive to the spatial arrangement. At the same time, it avoids the problem of stress concentration caused by the subframe longitudinal beams having to avoid each other, thus improving strength and durability.

[0057] Example 6

[0058] Based on any one of Examples 2-5, such as Figures 7-9As shown, the energy absorption mechanism also includes a sliding hole 1205, which is located on the side of the fixed box 1204 near the anti-collision beam 1203. A drive column 1206 is slidably installed in the sliding hole 1205. One end of the drive column 1206, away from the fixed box 1204, extends to the outside of the fixed box 1204 and is provided with a mounting bracket 1207. A buffer spring 1208 is sleeved on the outside of the drive column 1206. One end of the buffer spring 1208 is connected to the fixed box 1204, and the other end of the buffer spring 1208 is connected to the mounting bracket 1207. The mounting bracket 1207 is U-shaped, and sliding rods 1209 are provided on the upper and lower sides of the mounting bracket 1207. Sliding grooves corresponding to the sliding rods 1209 are provided on the inner walls of the upper and lower sides of the energy absorption box body 1201. The sliding grooves are provided along the length of the energy absorption box body 1201. 9. One end of the bracket 1207 extends into the groove and is slidably connected to the inner wall of the groove. A rotating shaft is rotatably installed inside the bracket 1207. A first gear 1210 is installed on the rotating shaft. A first rack 1211 and a second rack 1212 are respectively installed on both sides of the first gear 1210. One side of the first rack 1211 and the second rack 1212 are respectively engaged with the first gear 1210. The other side of the first rack 1211 and the second rack 1212 are respectively slidably connected to the inner wall of the energy absorption box body 1201. The first rack 1211 and the second rack 1212 are centrally symmetrical about the center of the first gear 1210. The end of the second rack 1212 away from the fixed box 1204 is located inside the energy absorption box body 1201. A through hole corresponding to the second rack 1212 is provided on the front side of the energy absorption box body 1201.

[0059] The working principle and beneficial effects of the above technical solution are as follows: When a collision occurs at the front of the vehicle, the anti-collision beam 1203 first contacts the colliding object, and then pushes the first rack 1211 to slide towards the fixed box 1204. The return spring 1213 is gradually compressed. The compression of the return spring 1213 absorbs part of the impact force, allowing the front subframe to withstand impacts of a smaller degree. After the impact, under the action of the return spring 1213, the first rack 1211 slides away from the fixed box 1204 until the second rack 1212 contacts the fixed box 1204. At this time, the anti-collision beam 1203 returns to its original position, facilitating secondary use. Compared with disposable energy absorption devices, the energy absorption mechanism in this embodiment can be reused, further reducing costs. As the collision distance increases, the first rack 1211 meshes with the first gear 1210 during the sliding process, driving the first gear 1210 to rotate. The rotation of the first gear 1210 drives the second rack. 1212 slides towards the anti-collision beam 1203. When the second rack 1212 contacts the anti-collision beam 1203, the first gear 1210 cannot rotate. At this time, the anti-collision beam 1203 drives the first gear 1210 to move towards the fixed box 1204 through the first rack 1211 and the second rack 1212. The first gear 1210 drives the mounting bracket 1207 to move through the rotating shaft. The mounting bracket 1207 slides towards the fixed box 1204 under the cooperation of the sliding rod 1209 and the sliding groove, and drives the drive column 1206 to slide in the sliding hole 1205. The buffer spring 1208 is compressed to further absorb the impact force, thereby effectively reducing the impact on the passengers in the vehicle and protecting the safety of the passengers. After the collision, under the action of the buffer spring 1208 and the return spring 1213, the energy absorption mechanism returns to its original position, which is convenient for repeated use, improves the service life of the energy absorption mechanism, reduces the use cost, and improves the passive safety of new energy vehicles.

[0060] Example 7

[0061] Based on Example 6, such as Figure 8 , Figure 9As shown, a first piston plate 1214 is installed inside the fixed box 1204. The first piston plate 1214 is slidably connected to the inner wall of the fixed box 1204. The first piston plate 1214 is connected to the drive column 1206 via a connecting rope. An oil injection pipe and an oil outlet pipe are respectively installed on the side wall of the fixed box 1204. The oil injection pipe and the oil outlet pipe are located behind the first piston plate 1214. One end of the oil injection pipe is connected to the inside of the fixed box 1204, and the other end of the oil injection pipe extends to the outside of the energy absorption box body 1201 and is equipped with a first valve. One end of the oil outlet pipe is connected to the inside of the fixed box 1204, and the other end of the oil outlet pipe extends to the outside of the energy absorption box body 1201 and is equipped with a second valve. A pressure pipe 1215 is installed behind the fixed box 1204. The pressure pipe 1215 is connected to the inner wall of the energy absorption box body 1201. The end of the pressure pipe 1215 away from the bolt 1202 is connected to the fixed box 1206 via a connecting pipe 1216. 04 The rear side is connected, and a second piston plate 1217 is slidably installed inside the pressure pipe 1215. A push rod 1218 is installed on the side of the second piston plate 1217 near the bolt 1202. The end of the push rod 1218 away from the second piston plate 1217 extends to the outside of the pressure pipe 1215 and is provided with a third rack 1219. The head of the bolt 1202 is located inside the fixed box 1204. The bolt 1202 is threadedly connected to the rear wall of the energy absorption box body 1201. A sleeve 1222 is fitted on the outside of the head of the bolt 1202. The sleeve 1222 is rotatably connected to the rear inner wall of the energy absorption box body 1201. A second gear 1220 is installed on the sleeve 1222. The third rack 1219 is located on the upper side of the second gear 1220 and meshes with the second gear 1220. The end of the third rack 1219 away from the push rod 1218 extends to the outside of the energy absorption box body 1201 and is provided with a push plate 1221.

[0062] The working principle and beneficial effects of the above technical solution are as follows: As the collision intensity increases, the drive column 1206 can push the first piston plate 1214 to slide within the fixed box 1204. The fixed box 1204 stores hydraulic oil. The sliding of the first piston plate 1214 pushes the hydraulic oil into the connecting pipe 1216, and then into the pressure pipe 1215 through the connecting pipe 1216. The diameter of the connecting pipe 1216 is much smaller than the cross-section of the fixed box 1204. Therefore, when the hydraulic oil flows from the fixed box 1204 into the connecting pipe 1216, the flow velocity increases due to the reduced cross-sectional area of ​​the connecting pipe 1216, thereby generating higher pressure inside the connecting pipe 1216. The increase in pressure helps to improve the energy absorption capacity. When a collision or impact occurs, energy can be absorbed and dispersed more effectively, further improving the energy absorption effect of the energy absorption mechanism. The hydraulic oil entering the pressure pipe 1215 can push the second piston plate 1217 to slide inside the pressure pipe 1215. The sliding of the second piston plate 1217 drives the push rod 1218 to slide outside the pressure pipe 1215. The push rod 1218 drives the third rack 1219 to move away from the pressure pipe 1215, and drives the push plate 1221 to move away from the energy absorption box body 1201. The third rack 1219 meshes with the second gear 1220. During the sliding process of the third rack 1219 along the top wall of the energy absorption box body 1201, it can drive the second gear 1220 to rotate. The sleeve 1222 rotates on the inner wall of the energy-absorbing box body 1201. The bolt 1202 is a hexagonal head bolt. The inner wall of the sleeve 1222 is adapted to the head of the bolt 1202, and the head of the bolt 1202 can slide along the inner wall of the sleeve 1222. The rotation of the sleeve 1222 can drive the bolt 1202 to rotate on the nut of the energy-absorbing box mounting bracket and the rear side wall of the energy-absorbing box body 1201. During the rotation of the bolt 1202, the collision energy is further absorbed, and the impact is further reduced. When the collision intensity exceeds the preset maximum collision intensity, the bolt 1202 can separate from the nut, causing the energy-absorbing box body 1201 to separate from the corresponding energy-absorbing box mounting bracket. The energy-absorbing box body 1201 deforms under severe impact. When the energy-absorbing box body 1201 is damaged, the energy is absorbed by the deformation of the energy-absorbing box body 1201, further absorbing the impact force, reducing the risk of injury, and improving safety. Since the bolt 1202 separates from the nut, the energy-absorbing box body 1201 can fall off after the front subframe separates from the collision object without manual removal, making it easy to replace the new energy-absorbing box body 1201. In addition, the damage to some energy-absorbing box bodies 1201 will not damage the nut and energy-absorbing box mounting bracket, so there is no need to replace the new energy-absorbing box mounting bracket. This helps to reduce the later maintenance cost of the front subframe and reduces the probability of damage to the front subframe after a collision. When the subframe is not damaged, only the energy-absorbing box body needs to be replaced, which reduces maintenance costs to a certain extent.Both ends of the sleeve 1222 are open. When installing the energy-absorbing box body 1201, a placement opening is provided on the side wall of the energy-absorbing box body 1201. The bolt 1202 is moved into the energy-absorbing box body 1201 through this placement opening. Then, the bolt 1202 is inserted into the sleeve 1222 through the opening, with its head held in place. Pushing the push plate 1221 then screws the bolt 1202 into the threaded hole on the rear side wall of the energy-absorbing box body 1201. Continuing to push the push plate 1221 causes the bolt 1202 to rotate further, allowing it to be screwed into the nut of the energy-absorbing box mounting bracket. This achieves rapid installation of the energy-absorbing box body 1201.

[0063] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0064] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0065] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A front subframe for automobiles, characterized in that, include: The structure consists of a front crossbeam (1), a left longitudinal beam (2), a right longitudinal beam (3), and a rear crossbeam (4). The rear ends of the left longitudinal beam (2) and the right longitudinal beam (3) are connected by the rear crossbeam (4). The front ends of the left longitudinal beam (2) and the right longitudinal beam (3) are connected by the front crossbeam (1). A left energy-absorbing box mounting bracket (12) is installed at the front end of the left longitudinal beam (2), and a right energy-absorbing box mounting bracket (13) is installed at the front end of the right longitudinal beam (3). Energy-absorbing box bodies (1201) are installed on the left energy-absorbing box mounting bracket (12) and the right energy-absorbing box mounting bracket (13). The rear sides of the two energy-absorbing box bodies (1201) are connected to the left energy-absorbing box mounting bracket (12) and the right energy-absorbing box mounting bracket (13) respectively by bolts (1202). The bracket (13) is connected, and a crash beam (1203) is provided in front of the energy-absorbing box body (1201). An energy-absorbing mechanism is provided inside the energy-absorbing box body (1201). The energy-absorbing mechanism includes a fixed box (1204). The outer wall of the fixed box (1204) is fixedly connected to the inner wall of the energy-absorbing box body (1201). A first rack (1211) is provided inside the energy-absorbing box body (1201). One end of the first rack (1211) near the fixed box (1204) is connected to the fixed box (1204) through a return spring (1213). The other end of the first rack (1211) extends to the outside of the energy-absorbing box body (1201) and is connected to the crash beam (1203). The energy absorption mechanism also includes a sliding hole (1205), which is located on the side of the fixed box (1204) near the anti-collision beam (1203). A drive column (1206) is slidably installed in the sliding hole (1205). The end of the drive column (1206) away from the fixed box (1204) extends to the outside of the fixed box (1204) and is provided with a mounting bracket (1207). A buffer spring (1208) is sleeved on the outside of the drive column (1206). One end of the buffer spring (1208) is connected to the fixed box (1204), and the other end of the buffer spring (1208) is connected to the mounting bracket (1207). The mounting bracket (1207) is U-shaped. Sliding rods (1209) are provided on the upper and lower sides of the mounting bracket (1207). The inner walls of the upper and lower sides of the energy absorption box body (1201) are provided with grooves corresponding to the sliding rods (1209). The grooves are provided along the length of the energy absorption box body (1201). 9) The end furthest from the mounting bracket (1207) extends into the slide groove and slides in connection with the inner wall of the slide groove. A rotating shaft is rotatably installed inside the mounting bracket (1207). A first gear (1210) is installed on the rotating shaft. A first rack (1211) and a second rack (1212) are respectively installed on both sides of the first gear (1210). One side of the first rack (1211) and the second rack (1212) mesh with the first gear (1210). The first rack (1211) The other side of the first rack (1211) and the second rack (1212) are slidably connected to the inner wall of the energy-absorbing box body (1201). The first rack (1211) and the second rack (1212) are centrally symmetrical about the center of the first gear (1210). The end of the second rack (1212) away from the fixed box (1204) is located inside the energy-absorbing box body (1201). The front side of the energy-absorbing box body (1201) is provided with a through hole corresponding to the second rack (1212).

2. The front subframe for an automobile according to claim 1, characterized in that, A left swing arm mounting bracket (5) is set on the side of the left longitudinal beam (2) away from the right longitudinal beam (3). The left swing arm mounting bracket (5) is located near the middle of the left longitudinal beam (2). A left steering gear mounting bracket (10) is set on the left longitudinal beam (2). A right swing arm mounting bracket (6) is set on the side of the right longitudinal beam (3) away from the left longitudinal beam (2). The right swing arm mounting bracket is located near the middle of the right longitudinal beam (3). A right steering gear mounting bracket (9) is set on the right longitudinal beam (3). A left suspension mounting bracket (7) and a right suspension mounting bracket (8) are set on the front side of the rear cross beam (4). A rear steering gear mounting bracket (11) is set on the rear cross beam (4). One side of the rear steering gear mounting bracket (11) is connected to the left suspension mounting bracket (7).

3. The front subframe for an automobile according to claim 2, characterized in that, The left longitudinal beam (2) includes a left longitudinal beam upper plate (21) and a left longitudinal beam lower plate (22). A first mounting hole (2101) is provided on the upper surface of the front end of the left longitudinal beam upper plate (21). The first mounting hole (2101) passes through the left longitudinal beam lower plate (22). A first mounting sleeve (2111) is provided inside the first mounting hole (2101).

4. The front subframe for an automobile according to claim 3, characterized in that, A first groove (211) is provided on the upper surface of the upper plate (21) of the left longitudinal beam. The first groove (211) is located behind the first mounting hole (2101). A fifth mounting hole (2105) and a sixth mounting hole (2106) are provided in the first groove (211). Nuts are welded to the back of the fifth mounting hole (2105) and the sixth mounting hole (2106). A fourth mounting hole (2104) is provided in front of the fifth mounting hole (2105). The fourth mounting hole (2104) penetrates the lower plate (22) of the left longitudinal beam. A sixth mounting sleeve (2116) is provided in the fourth mounting hole (2104).

5. A front subframe for automobiles according to claim 4, characterized in that, A second groove (212) is provided on the upper surface of the upper plate (21) of the left longitudinal beam. The second groove (212) is located behind the first groove (211). The left swing arm mounting bracket (5) is located outside the second groove (212). One side of the left swing arm mounting bracket (5) overlaps on the plane of the second groove (212).

6. A front subframe for automobiles according to claim 5, characterized in that, A steering gear left mounting bracket (10) is provided on the upper surface of the upper plate (21) of the left longitudinal beam. The steering gear left mounting bracket (10) is located behind the left swing arm mounting bracket (5). An eleventh mounting hole (1001) is provided on the steering gear left mounting bracket (10). The eleventh mounting hole (1001) penetrates the upper plate (21) of the left longitudinal beam. A seventh mounting sleeve (101) is provided inside the eleventh mounting hole (1001). A first inclined platform is provided on the outer wall of the seventh mounting sleeve (101). A first flange threaded pipe (102) is provided on the top wall of the upper plate (21) of the left longitudinal beam. The first flange threaded pipe (102) is located directly below the seventh mounting sleeve (101).

7. A front subframe for automobiles according to claim 6, characterized in that, The upper surface of the upper plate (21) of the left longitudinal beam is provided with the seventh mounting hole (2107), the eighth mounting hole (2108), the ninth mounting hole (2109) and the tenth mounting hole (2110) in sequence from front to back. The seventh mounting hole (2107) is located behind the left mounting bracket (10) of the steering gear. The first stabilizer bar mounting nut (2118) is welded to the back of the seventh mounting hole (2107). The second stabilizer bar mounting nut (2119) is welded to the back of the eighth mounting hole (2108). The ninth mounting hole (2109) and the tenth mounting hole (2110) penetrate the lower plate (22) of the left longitudinal beam. The fourth mounting sleeve (2114) is provided in the ninth mounting hole (2109). The fifth mounting sleeve (2115) is provided in the tenth mounting hole (2110). The first reinforcing bracket (2117) is provided at the rear end of the fifth mounting sleeve (2115). The upper and lower sides of the first reinforcing bracket (2117) are connected to the upper plate (21) of the left longitudinal beam and the lower plate (22) of the left longitudinal beam, respectively.

8. A front subframe for an automobile according to claim 7, characterized in that, The upper surface of the upper plate (21) of the left longitudinal beam is provided with a second mounting hole (2102) and a third mounting hole (2103) from front to back. The second mounting hole (2102) is located behind the tenth mounting hole (2110). The second mounting hole (2102) and the third mounting hole (2103) both penetrate the lower plate (22) of the left longitudinal beam. The second mounting hole (2102) is provided with a second mounting sleeve (2112), and the third mounting hole (2103) is provided with a third mounting sleeve (2113).

9. A front subframe for an automobile according to claim 2, characterized in that, The rear crossbeam (4) includes a rear crossbeam upper plate (41) and a rear crossbeam lower plate (42). A third groove (411) is provided on the upper surface of the rear crossbeam upper plate (41), a fourth groove (412) is provided on the side of the rear crossbeam upper plate (41) near the front crossbeam (1), a fifth groove (413) is provided on the side of the rear crossbeam lower plate (42) near the front crossbeam (1), and a sixth groove (414) is provided on the lower surface of the rear crossbeam lower plate (42).

10. A front subframe for an automobile according to claim 2, characterized in that, A twelfth mounting hole (1101) is provided on the rear mounting bracket (11) of the steering gear. The twelfth mounting hole (1101) passes through the upper plate (41) of the rear crossbeam. An eighth mounting sleeve (111) is provided inside the twelfth mounting hole (1101). A second inclined platform is provided on the outer wall of the eighth mounting sleeve (111). A second flange threaded pipe (112) is provided on the top wall of the upper plate (41) of the rear crossbeam. The second flange threaded pipe (112) is located directly below the eighth mounting sleeve (111).

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