A helicopter vortex tube arrangement

Abstract

The application discloses a kind of helicopter vortex pipe arrangement structure, it is related to sand prevention device technical field.The air inlet panel inner side plate and air inlet panel outer side plate are all in bending state, the orthographic projection position of vortex pipe outer wall on inner panel can be infinitely close to the boundary line of two pipe arrangement faces.The present application can be arranged more vortex pipe, thus it is favorable to increase the air intake of helicopter engine, reduce air intake pressure loss, very favorable to helicopter engine work;The front end of sand prevention device is smaller, which is favorable to reduce the flight resistance of helicopter;Simplify panel processing technology, there is no panel rounding process, which means quality improvement and cost reduction;Rivets are arranged in the sandwich of air inlet panel inner side plate and air inlet panel outer side plate, and do not appear on one side of air inlet passage, so that individual shedding, broken rivets will not enter the helicopter engine with air, damage the engine.

Description

TECHNICAL FIELD

[0001] The present application relates to sand prevention device technical field, specifically to a kind of helicopter vortex tube arrangement structure. BACKGROUND

[0002] Herein the sand prevention device used by helicopter is taken as an example to clarify the state of the art.

[0003] In order to ensure the take-off and flight life of helicopter engine in sand dust environment, air inlet protection device is installed in front of engine air inlet. A large number of vortex tubes are arranged on the air inlet panel of such device for air purification.

[0004] 1. The number of vortex tubes is the key factor to determine the air inlet pressure loss and purification efficiency of air inlet protection device. In order to arrange more vortex tubes, the sand prevention device needs to have larger volume or surface area.

[0005] 2. After installing sand prevention device, the frontal area of helicopter increases, which means the increase of resistance. Therefore, the frontal area of sand prevention device needs to be as small as possible. It can be seen that the number of vortex tubes and the size of the outer contour of sand prevention device are a pair of mutually restrictive problems.

[0006] 3. In addition, the sand prevention device with conical surface has poor workability, and various installation problems often occur during production.

[0007] 4. The connecting rivet head of inner panel and reinforcing beam between inner and outer panels is directed to the air inlet passage. Once the rivet falls off, it will enter the helicopter engine, causing engine stoppage and other hazards. SUMMARY

[0008] The present application aims to provide a helicopter vortex tube arrangement structure to solve the problems raised in the background.

[0009] To achieve the above-mentioned purpose, the present application provides the following technical solution: a helicopter vortex tube arrangement structure, comprising:

[0010] The inner side plate of air inlet panel and the outer side plate of air inlet panel are both in a bent state, and the orthographic projection position of vortex tube outer wall on inner panel can be infinitely close to the boundary line of two pipe arrangement surfaces;

[0011] The space where vortex tube cannot be arranged is used as sand discharge channel, and the inner side plate of air inlet panel and the outer side plate of air inlet panel and the vortex tube contour boundary on both sides of the bending part form V-shaped sand discharge channel.

[0012] Further to the scheme, the inner side plate of the air inlet panel comprises inner panel one and inner panel two, the outer side plate of the air inlet panel comprises outer panel one and outer panel two, and an included angle is arranged at the joint of the inner panel one and the inner panel two, and an included angle is arranged at the joint of the outer panel one and the outer panel two.

[0013] Further to the scheme, a longitudinal beam is arranged between the outer side plate and the inner side plate of the air inlet panel, one end of the longitudinal beam is overlapped with the inner panel one and the inner panel two and is fixed with the inner panel one and the inner panel two by rivets, and the other end of the longitudinal beam is overlapped with the outer panel one and the outer panel two and is fixed with the outer panel one and the outer panel two by rivets.

[0014] Further to the scheme, the joint of the longitudinal beam and the inner panel one and the inner panel two is located between the included layers of the inner side plate and the outer side plate of the air inlet panel.

[0015] Further to the scheme, the joint of the inner panel one and the inner panel two is respectively provided with a turn-up one and a turn-up two, the round corner range of the longitudinal beam covers two layers of material thickness of the turn-up one and the turn-up two, the space of the inner panel is saved, one end of the outer panel one is provided with a turn-up three, and the upper end outer surface of the longitudinal beam is attached to the turn-up three of the inner outer panel one, so that the length of the longitudinal beam in the up-down direction is the shortest.

[0016] Further to the scheme, the longitudinal beam is designed to be inclined, and the rivet gun avoids the downstream pipe of the scroll pipe.

[0017] Further to the scheme, the distance between the rivets is basically consistent with the distance between the scroll pipes.

[0018] Further to the scheme, the inner panel one is integrally formed with the longitudinal beam, and / or the inner panel two is integrally formed with the longitudinal beam, and / or the outer panel one is integrally formed with the longitudinal beam.

[0019] Further to the scheme, the rivets are located between the included layers of the inner side plate and the outer side plate of the air inlet panel, and the rivets do not fall into the air inlet channel, so that the rivets do not enter the engine.

[0020] Compared with the prior art, the beneficial effects of the present application are:

[0021] 1. The problem that the mounting round holes of the scroll pipes on the outer panel and the inner panel are deformed after the panel is rolled is solved. After rolling, the diameters of the round holes in the longitudinal and transverse directions will change, and the plane where the round holes are originally located will become an undulating arc surface, which will cause problems such as difficult assembly of the scroll pipes, edge extrusion, and scrap, etc. The quality problem after the scroll pipes are installed is extremely difficult to troubleshoot due to the small size and large quantity of the scroll pipes, and if there is omission in the production and inspection process, the problem will be brought to the helicopter, causing hidden dangers.

[0022] 2. This design allows for the placement of more vortex tubes, which helps increase the air intake of the helicopter engine and reduce intake pressure loss, thus greatly benefiting the operation of the helicopter engine.

[0023] 3. The rivets are located in the interlayer between the inner and outer panels of the air intake panel, and do not appear on the side of the air intake passage. Therefore, any detached or broken rivets will not enter the helicopter engine with the air and damage the engine.

[0024] 4. This solution simplifies the panel processing technology, eliminating the need for panel rounding; this means improved quality and reduced costs.

[0025] 5. The longitudinal (i.e., the forward and backward direction of the helicopter) structure of the sand protection device has been reinforced to a certain extent, which improves its support capacity during bird strikes.

[0026] 6. In this design, the frontal windward area of ​​the sand-proof device is smaller, which helps reduce the flight drag of the helicopter.

[0027] 7. This solution has a smaller sand-proof device, saving material and reducing weight.

[0028] 8. In this design, the mounting holes of the scroll tubes on the outer and inner panels are very easy to align and will not be affected by the cumulative error during the panel rolling process.

[0029] 9. After the vortex tube is assembled, the outer panel with the upstream tube and the inner panel with the downstream tube are easy to assemble, and there will be no lateral obstruction problem caused by the vortex tube when assembling the conical outer and inner panels.

[0030] 10. This design avoids sharp edges of sheet metal near the plastic scroll tube, making the scroll tube less susceptible to damage.

[0031] 11. All rivet mounting surfaces are flat, ensuring good panel fit and preventing curved surfaces from touching flat surfaces.

[0032] 12. The panel segmented overlapping structure is simple, especially the outer panel. The outer panels can be connected to adjacent outer panels by bending them at appropriate positions. This solves the problem of segmented overlapping of conical panels, where one of the two overlapping panels of a conical panel might need to have a small step structure or require additional connecting plates.

[0033] 13. Generally, the inner panel is riveted after the scroll tube is installed. Therefore, the scroll tube installed on the inner panel should not obstruct the rivet gun from driving the rivets or interfere with the rivet head. The inclined design of the inner panel's flange fully solves this problem, making it easier to drive the rivets from the obtuse angle side and avoiding the downstream tube of the scroll tube. Attached Figure Description

[0034] Figure 1This is a schematic diagram comparing the outer surface area of ​​the conical air intake panel and the multi-faceted air intake panel of the present invention.

[0035] Figure 2 This is a schematic diagram of the rivet position state structure of the conical air intake panel of the present invention;

[0036] Figure 3 This is a schematic diagram of the polyhedral air intake panel structure with vortex tube arrangement of the present invention.

[0037] Figure 4 This is a schematic diagram of the confluence channel in the polyhedral scheme of the present invention;

[0038] Figure 5 This is a schematic diagram of the structure of an embodiment of the polyhedral air intake panel of the present invention;

[0039] Figure 6 This is a schematic diagram of the extended state structure of the polyhedral scheme of the present invention;

[0040] Figure 7 This is a schematic diagram of the overall structure of the present invention;

[0041] Figure 8 For the present invention Figure 7 A schematic diagram of the cross-sectional structure at the centerline L;

[0042] Figure 9 This is a schematic diagram of the area of ​​the front windward end face of the present invention;

[0043] Figure 10 This is a schematic diagram of one embodiment of the present invention;

[0044] Figure 11 This is a schematic diagram of one embodiment of the present invention;

[0045] Figure 12 This is a schematic diagram of one embodiment of the present invention.

[0046] In the diagram: 1. Inner panel one; 101. Flanged edge one; 2. Inner panel two; 201. Flanged edge two; 3. Outer panel one; 301. Flanged edge three; 4. Outer panel two; 5. Longitudinal beam; 6. Rivet. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Given a fixed outer contour boundary, the outer surface area of ​​a cylinder is always larger than that of a polygonal prism. It is generally believed that a cylinder has more space to accommodate vortex tubes. Similarly, it is assumed that the outer surface of a cone can accommodate more vortex tubes (hereinafter referred to as tube arrangement) than the outer surface of a polyhedron. Figure 1 It can be seen that, under the same outer contour constraints, the outer surface of a cone is indeed larger than that of a polyhedron.

[0049] like Figure 2 As shown, a conical surface design is generally used to accommodate more scroll tubes. The processing technology of the intake panel usually involves first cutting out the holes and boundaries, and then performing processes such as rolling and bending. However, the scroll tube mounting holes on the inner and outer sides of the intake panel will inevitably deform after the panel is rolled. After rolling, the diameter of the holes will change in both the longitudinal and transverse directions, and the plane containing the holes will become an undulating arc surface. These two problems directly lead to batch problems such as difficulty in assembling scroll tubes, edge extrusion, and scrap. In addition, the scroll tubes on the inner and outer sides of the outer intake panel... The accumulation of positional errors in the mounting holes after rolling makes it very difficult to align the upstream and downstream vortex tubes. Quality problems after vortex tube installation are extremely difficult to troubleshoot due to the small size, large number, and small gaps (usually thousands of them arranged closely together). Oversights are inevitable during production and inspection, which can lead to problems being carried to the helicopter and causing hidden dangers. Furthermore, the reinforcing beam between the inner and outer panels has rivet ends facing the air intake channel. If the rivet falls off, the broken rivet parts can enter the helicopter engine and cause damage to the helicopter.

[0050] Example 1

[0051] like Figure 3 As shown, the present invention provides a technical solution, a helicopter vortex tube arrangement structure, comprising:

[0052] Both the inner and outer sides of the air intake panel are bent, and the projected position of the outer wall of the vortex tube on the inner panel can be infinitely close to the dividing line between the two pipe surfaces.

[0053] It is important to understand that the minimum distance from the orthographic projection of the outer wall of the vortex tube onto the inner panel to the boundary line between the two tube layout surfaces is equal to the size of the rounded corner influence area plus the safety distance. The safety distance can be reduced, even to 0. This distance is determined by two factors. Generally, the first thing to consider is the cross-sectional area requirement of the sand discharge channel (convergence channel area), and the second thing to consider is the physical space for the vortex tube layout.

[0054] The specific reasons are as follows:

[0055] ac: The distance from the center line (boundary line) of the panel to the outer wall of the vortex tube in the V-shaped or rectangular space, calculated by means of calculation.

[0056] AC: The distance from the centerline of the panel to the outer wall of the vortex tube required to achieve the inner panel flange, strengthen the beam arrangement, and arrange the vortex tube in physical space.

[0057] 1. Physical structural limitations of components: Refer to Figure 2 and Figure 5 In the conical surface scheme, the distance between points AC is 12mm. In the polyhedral scheme, the distance between points AC is 6mm (the AC value for the conical surface is the distance from the edge of the vortex tube to the rivet point; the AC value for the polyhedral surface is the distance from the edge of the vortex tube to the midpoint between the two panels). In the conical surface scheme, the AC value of 12mm is its limit under actual working conditions (half the 20mm length of the reinforcing beam flange in the conical surface plus the 2mm safety distance left between the edge of the vortex tube and the boundary of the longitudinal beam). In the polyhedral scheme, the inner panel fillet radius R is 4mm, and the safety distance between the edge of the vortex tube and the fillet boundary is 2mm. Therefore, the AC value of 6mm is the limit under actual working conditions for the polyhedral scheme. The polyhedral scheme utilizes the inner panel space occupied by the original reinforcing beam's lower surface, reducing the distance between the vortex tubes on two adjacent inner panels.

[0058] 2. Size requirements for the gas confluence channel: A V-shaped space formed by vortex tubes arranged on a polyhedron serves as the sand discharge channel, requiring virtually no additional space for vortex tubes. Calculation results show that the AC value of the polyhedron scheme is mostly negative, thus easily meeting the area requirements of the confluence channel. Compared to the conical surface scheme, the spacing between vortex tubes on adjacent inner panels is further reduced, providing more space on the inner panels for vortex tube arrangement.

[0059] Table 1 / Arrangement of Polyhedral Vortex Tubes

[0060]

[0061] Table 2 / Number of Conical Vortex Tube Arrangements

[0062]

[0063] The essence of the AC value is that the smaller the gap between the vortex tube and the panel boundary line, the higher the panel space utilization rate and the more vortex tubes are arranged. In this embodiment, through... Figure 3 and Figure 4 It can be seen that the area of ​​the merging channel can be converted into the area of ​​a rectangle, that is, s = 53 × the width of the merging channel. Figure 8 As can be seen, in this embodiment, the polyhedral scheme is half of an equilateral octahedron, and each interior angle of the polyhedron is 135°. Therefore... Figure 4 In this embodiment, x = 53 × tan22.5°, the area of ​​the confluence channel can be considered as the sum of the areas of two trapezoids. Therefore, the area of ​​the confluence channel is... ,Right now After conversion, After substituting the flow channel area from the above polyhedral vortex tube arrangement table into the table, it is clear that when the flow channel area is smaller, the AC value is smaller, and may even be negative.

[0064] This also proves that when the AC value is less than the physical structural limit of the component (4mm for the inner panel fillet plus 2mm for the safety distance between the edge of the vortex tube and the fillet boundary), or even negative, it means that the vortex tube can be closer to the panel boundary line to save space. The table above shows that the first 9 sets of AC values ​​of the polyhedral scheme range from -9.7mm to -0.7mm, all of which are less than the structural safety value of 6mm and are negative. This means that the vortex tube not only does not occupy the necessary space of the confluence channel, but also, due to the design of the V-shaped channel, even if the vortex tube crosses the center line, the confluence channel can still maintain a sufficient cross-section. Therefore, more vortex tubes can be arranged. Although it is not practical to implement when the AC value is negative, it demonstrates that the polyhedral scheme can arrange more vortex tubes while maintaining the cross-sectional area requirement of the confluence channel.

[0065] It can be seen that the distance from the center line of the panel to the outer wall of the vortex tube in the V-shaped space is constantly decreasing and even becomes negative, so there is no need to occupy additional space. It is not until row 15 that the space of the air confluence channel needs to be considered, because only in row 14 does the value of 6.6mm, which is greater than the structural limit of 6mm, appear, which is greater than the above structural value AC=6. In addition, it can be seen that the total number of vortex tubes that can be arranged in the polyhedral scheme is greater than that in the conical scheme (294>282). That is, by using this embodiment, the polyhedral scheme can arrange more vortex tubes than the conical scheme.

[0066] Meanwhile, since the arrangement of vortex tubes must meet both the physical structural requirements and the needs of the confluence space, the maximum value of AC and ac must be taken as the placement position of the vortex tubes, regardless of the scheme. This is why a smaller polyhedral panel can accommodate more vortex tubes.

[0067] Example 2

[0068] like Figure 5 As shown, the inner side panel of the air intake panel includes inner panel 1 and inner panel 2, and the outer side panel of the air intake panel includes outer panel 3 and outer panel 4. An angle is provided at the junction of inner panel 1 and inner panel 2, and an angle is provided at the junction of outer panel 3 and outer panel 4. A longitudinal beam 5 is provided between the inner side panels of the air intake panel. One end of the longitudinal beam 5 overlaps with inner panel 1 and inner panel 2 and is fixed to inner panel 1 and inner panel 2 with rivets 6. The other end of the longitudinal beam 5 overlaps with outer panel 3 and outer panel 2 and is fixed to outer panel 3 and outer panel 2 with rivets 6.

[0069] Regarding the above technical solutions, such as Figure 5 As shown, the connection between the longitudinal beam 5 and the inner panel 1 and the inner panel 2 is located at the point where the inner side panel and the outer side panel of the intake panel are in contact. In this way, if the rivet 6 falls off, it will fall into the gap between the inner and outer panels and will not enter the engine, thus eliminating the problem of the rivet head damaging the engine.

[0070] Regarding the above technical solutions, such as Figure 5 As shown, it can be understood that flange 101 and flange 201 are respectively provided at the junction of inner panel 1 and inner panel 2. One end of the longitudinal beam 5 is sandwiched between flange 101 and flange 201. One end of outer panel 3 is provided with flange 301. The upper outer surface of the longitudinal beam 5 is attached to flange 301 of the inner side of outer panel 3, so that the vertical length of the longitudinal beam 5 is minimized. From the cross-section Figure 2 As can be seen above, in the conical surface scheme, the sharp corners of the straight edges of the longitudinal beam 5 are prone to interference with the vortex tube, which can easily damage the vortex tube and is difficult to handle. In this embodiment, there are no sharp corners near the vortex tube on the outer panel, but rather a circular arc facing away from it. On the inner panel, the edge of the vortex tube is also far away from the sharp corners, and even if there is a slight misalignment, it will fall on a circular arc with a gentler slope, so as not to damage the vortex tube.

[0071] Regarding the above technical solutions, such as Figure 5 As shown, the scroll tubes are installed on the planes of the inner and outer sides of the intake panel. Traditional intake panels with conical surfaces typically involve cutting out holes and boundaries before rolling and bending. However, the mounting holes for the scroll tubes on the inner and outer panels inevitably deform after rolling. The diameter of the holes changes in both the longitudinal and transverse directions, and the plane containing the holes becomes an undulating arc. These two issues directly lead to difficulties in scroll tube assembly, edge extrusion, and batch defects. Furthermore, the accumulated positional error of the scroll tube mounting holes on the inner panel after rolling is very detrimental to the alignment of the upstream and downstream scroll tubes. In the above embodiment, however, the alignment of the scroll tube mounting holes on the inner and outer sides of the intake panel is very easy and is not affected by the accumulated errors during the panel rolling process.

[0072] Example 3

[0073] like Figure 7 and Figure 8 As shown, the longitudinal beam 5 is designed with an incline, and rivets 6 are driven from the side with more space, allowing the rivet gun to avoid the downstream pipe of the vortex tube. Figure 8 As shown, in actual operation, the inner panel is usually riveted after the scroll tube is installed. Therefore, the scroll tube installed on the inner panel cannot prevent the rivet gun from driving the rivet 6 or interfere with the rivet head. The inclined design of the inner panel flange fully solves this problem, which is conducive to driving the rivet 6 from the obtuse angle side and avoiding the downstream tube of the scroll tube.

[0074] Meanwhile, the spacing between rivets 6 is basically the same as the spacing between the volute tubes, ensuring that the ends of rivets 6 fully avoid the volute tubes. The distances from the volute tubes to the boundary vary, conforming to the spacing rule; therefore, rivets 6 are placed at the maximum distance, ensuring that the ends of rivets 6 fully avoid the volute tubes. Figure 6 As shown.

[0075] like Figure 9 As shown, under the same boundary contour constraints, the frontal windward area of ​​the sand-proof device in this embodiment is smaller, which is beneficial to reducing the flight drag of helicopters.

[0076] Optional, such as Figure 10 As shown, the longitudinal beam 5 can be made into the same part as the inner panel 1, inner panel 2, outer panel 3, or outer panel 4. Taking the inner panel 1 as an example, the longitudinal beam 5 is integrally formed with the inner panel 1, which reduces the assembly difficulty and structural strength.

[0077] Optional, such as Figure 12 As shown, inner panel 1 and inner panel 2 are made in the form of bisecting angles, and the reinforcing beam is deformable or the bending angle is less than 90 degrees;

[0078] Optionally, inner panel 1, inner panel 2, or even longitudinal beam 5 can be welded together with the panels by means of laser welding or other methods to reduce the risk of rivets 6 falling off and increase the structural integrity and strength.

[0079] Optional, such as Figure 11 As shown, inner panel 1 and inner panel 2 are bent in the same way, and the outer panel is bent into a flat area of ​​about 40mm on top, which is connected to the longitudinal beam 5.

[0080] Optionally, the longitudinal beam 5 can be removed and a transverse support beam can be used, which is directly connected to the fuselage, while still ensuring that the vortex tube is arranged to the edge of the inner panel.

[0081] Regarding the above embodiments, it can also be understood that, due to the adoption of the polyhedral design, the frontal windward area of ​​the sand-proof device is smaller, which is beneficial to reducing the flight drag of the helicopter. Furthermore, the longitudinal (i.e., the forward and backward direction of the helicopter) structure of the sand-proof device is enhanced to a certain extent, improving the support capacity during bird strikes.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended embodiments and their equivalents.

Claims

1. A helicopter vortex tube arrangement structure, characterized in that, include: The air intake panel inner side panel and the air intake panel outer side panel, the air intake panel inner side panel includes several inner panel one (1) and inner panel two (2), the air intake panel outer side panel includes several outer panel one (3) and outer panel two (4), the inner panel one (1) and inner panel two (2) are provided with an angle, and the outer panel one (3) and outer panel two (4) are provided with an angle; The orthographic projection of the outer wall of the vortex tube on the inner panel can be infinitely close to the boundary line between two adjacent panels. The space where the vortex tube cannot be arranged is used as a sand discharge channel. The inner side plate of the air intake panel and the outer side plate of the air intake panel, together with the outline boundary of the vortex tube on both sides of the bend, form a V-shaped sand discharge channel. While meeting the requirements of the sand discharge channel, the spacing between the vortex tubes on adjacent inner panels is reduced, allowing more space on the inner panel to arrange the vortex tube. A longitudinal beam (5) is provided between the outer side panel and the inner side panel of the air intake panel. The connection between the longitudinal beam (5) and the inner panel one (1) and the inner panel two (2) is located between the inner side panel and the outer side panel of the air intake panel. The rivet (6) is located between the inner side panel and the outer side panel of the air intake panel. The rivet (6) will not fall out and enter the air intake passage, thus preventing the rivet (6) from entering the engine.

2. The helicopter vortex tube arrangement structure according to claim 1, characterized in that: One end of the longitudinal beam (5) overlaps with the inner panel 1 (1) and the inner panel 2 (2) and is fixed to the inner panel 1 (1) and the inner panel 2 (2) with rivets (6). The other end of the longitudinal beam (5) overlaps with the outer panel 1 (3) and the outer panel 2 (4) and is fixed to the outer panel 1 (3) and the outer panel 2 (4) with rivets (6).

3. The helicopter vortex tube arrangement structure according to claim 2, characterized in that: At the junction of the inner panel 1 (1) and the inner panel 2 (2), flange 1 (101) and flange 2 (201) are respectively provided. The rounded corner of the longitudinal beam (5) covers the two layers of material thickness of flange 1 (101) and flange 2 (201), saving the planar space on the inner panel that can be used to arrange the vortex tube. One end of the outer panel 1 (3) is provided with flange 3 (301). The outer surface of the upper end of the longitudinal beam (5) is attached to the flange 3 (301) of the inner side of the outer panel 1 (3), so that the length of the longitudinal beam (5) in the vertical direction is the shortest.

4. The helicopter vortex tube arrangement structure according to claim 2, characterized in that: The longitudinal beam (5) is designed to be inclined, and rivets (6) are driven from the side with the larger space, with the rivet gun avoiding the downstream pipe of the vortex tube.

5. The helicopter vortex tube arrangement structure according to claim 1, characterized in that: The spacing of the rivets (6) is consistent with the spacing of the vortex tube.

6. The helicopter vortex tube arrangement structure according to claim 2, characterized in that: The inner panel 1 (1) is integrally formed with the longitudinal beam (5), and / or the inner panel 2 (2) is integrally formed with the longitudinal beam (5), and / or the outer panel 1 (3) is integrally formed with the longitudinal beam (5).

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