A storage tank with a rod type rear bottom force transmission structure and a carrier rocket

Abstract

This invention provides a propellant tank and launch vehicle with a rod-type rear bottom force transmission structure, comprising a front bottom, a cylindrical section, and a rear bottom connected in sequence. The rear bottom houses the rod-type force transmission structure, which includes a force transmission rod, a connector body fixedly connected to both ends of the force transmission rod, and a base plate. A thrust ring is provided at the end of the rear bottom, and the base plate is detachably connected to the thrust ring. The cylindrical section includes axially arranged stringers, the bottom ends of which are detachably connected to the connector body. This technical solution employs a rod-type rear bottom force transmission structure, eliminating the need for welded fins as in existing technologies. This results in better load-bearing capacity, higher structural reliability, and the detachable design allows for reusability of the propellant tank, making it highly suitable for high-thrust rocket engines.

Description

Technical Field

[0001] This invention relates to the field of launch vehicle technology, and in particular to a propellant tank and launch vehicle with a rod-type rear bottom force transmission structure. Background Technology

[0002] The propellant tank is a crucial component of a rocket, primarily used to store propellant and withstand axial, bending, and shear loads. It mainly comprises the front tank bottom (front bottom), front short shell, cylindrical section, rear short shell, and rear tank bottom (rear bottom). Traditionally, the rocket engine is connected to the rear short shell, transmitting thrust through it. This structure results in a long engine frame, significant space occupation, and low structural efficiency. To save space and improve structural efficiency, existing technologies have developed methods that connect the engine to the rear bottom of the propellant tank, transmitting engine thrust through the rear bottom. For example, patent CN116291964A provides such a rear bottom force transmission structure, which uses fin-like reinforcing ribs to transfer engine thrust to the cylindrical section, solving the problem of large space occupation.

[0003] However, the inventors discovered that this improved technology still has at least the following problems: In the existing aft bottom force transmission structure, the reinforcing ribs are connected to the tank bottom by welding, resulting in numerous welds. These welds themselves weaken the overall strength of the aft bottom, and since they are all fillet welds, they are at risk of cracking under the coupled conditions of tank pressurization and engine thrust. Furthermore, the fillet welds in used tanks are likely to suffer varying degrees of damage, increasing the risk of cracking upon reuse. Therefore, if reuse is desired, the reinforcing ribs should be replaced. However, the welding method makes it impossible to replace the reinforcing ribs, thus hindering the reuse of existing tanks and failing to meet the current trend of reusable launch vehicles. Therefore, how to improve the aft bottom force transmission structure to meet the requirements of tank reuse is a problem that needs to be solved. Summary of the Invention

[0004] This invention provides a propellant tank and a launch vehicle, and more specifically, a propellant tank and a launch vehicle with a rod-type rear bottom force transmission structure, to solve the problems of poor reliability and inability to replace reinforcing ribs in existing rear bottom force transmission structures, thereby realizing the reuse of the propellant tank.

[0005] To achieve the above objectives, in one aspect, embodiments of the present invention provide a storage tank with a rod-type rear bottom force transmission structure, comprising a front bottom, a front short shell, a cylindrical section, a rear short shell, and a rear bottom connected in sequence, wherein a rod-type force transmission structure is provided inside the rear bottom; the rod-type force transmission structure includes a force transmission rod, a joint body and a bottom plate respectively fixedly connected to both ends of the force transmission rod; a thrust ring is provided at the end of the rear bottom, and the bottom plate and the thrust ring are detachably connected; the cylindrical section includes axially arranged stringers, and the bottom end of the stringers is detachably connected to the joint body.

[0006] Furthermore, there are multiple sets of rod-type force transmission structures, which are evenly distributed circumferentially.

[0007] Furthermore, each set of rod-type force transmission structures includes multiple circumferentially arranged force transmission rods, with the rear ends of the multiple force transmission rods fixedly connected together, and the front ends of the multiple force transmission rods respectively connected to different stringers.

[0008] Furthermore, each set of rod-type force transmission structures includes three force transmission rods, and the three force transmission rods are respectively connected to three sequentially adjacent stringers.

[0009] Furthermore, the two joint bodies, which are set adjacently and belong to two adjacent sets of rod-type force transmission structures, are connected together by a tie rod.

[0010] Furthermore, in each set of rod-type force transmission structures, a reinforcing crossbar is also provided between two adjacent force transmission rods.

[0011] Furthermore, the cylindrical section is composed of multiple circumferentially distributed cylindrical segments spliced ​​together; the cylindrical segments include an arc-shaped plate-like skin and multiple stringers, which are fixedly connected to the inner surface of the skin.

[0012] Furthermore, the cylindrical segment is a one-piece structure manufactured using an extrusion molding process.

[0013] Furthermore, multiple annular intermediate frames are coaxially arranged inside the cylindrical section. The outer side of the intermediate frame fits into the inner side of the stringer, and the intermediate frame is detachably connected to the stringer.

[0014] Meanwhile, embodiments of the present invention also provide a launch vehicle, including a rocket engine and a propellant tank with a rod-type rear bottom force transmission structure as described above; the rocket engine is connected to the thrust ring via a connecting frame. The rocket engine is also connected to the propellant outlet of the propellant tank via a delivery pipe.

[0015] The above technical solution has the following beneficial effects:

[0016] This technical solution adopts a rod-type rear bottom force transmission structure, which replaces the welded reinforcing ribs in the existing technology. The rod-type force transmission structure has a better load-bearing effect and eliminates the need for welding, thereby avoiding the strength reduction caused by welds and making the rear bottom structure more reliable. In addition, the rear bottom force transmission structure is connected in a detachable manner, which facilitates maintenance or replacement, ensures the reusability of the storage tank, and is more in line with current development trends.

[0017] In addition, this technical solution also has the following characteristics:

[0018] In existing technologies, tank wall panels are generally constructed by welding the skin and stringers. While this solves the problem of low production efficiency of traditional tanks to some extent, the large number of stringers required results in a very long total weld length. This leads to a long evaluation and inspection cycle for weld quality and increases the likelihood of welding quality issues affecting tank strength. In this technical solution, the tank wall panels are constructed by integrating the skin and stringers, significantly reducing the number and total length of welds, improving inspection efficiency, and greatly reducing the likelihood of welding quality problems. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a storage tank with a rod-type rear bottom force transmission structure according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the rod-type rear bottom force transmission structure in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the overall structure of the storage tank in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the cylindrical section in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of the cylindrical segment in an embodiment of the present invention;

[0025] Figure 6 This is a cross-sectional schematic diagram of a cylindrical segment in an embodiment of the present invention;

[0026] Figure 7 This is a cross-sectional schematic diagram of the middle frame in an embodiment of the present invention;

[0027] Icon labels:

[0028] 1. Front bottom; 2. Tube section; 21. Tube segment; 211. Skin; 212. Truss; 22. Intermediate frame; 3. Rear bottom; 31. Rear bottom shell; 32. Thrust ring; 4. Front short shell; 5. Rear short shell; 6. Longitudinal weld; 7. Circumferential weld; 8. Rod-type force transmission structure; 81. Force transmission rod; 82. Joint body; 83. Base plate; 84. Horizontal tie rod; 85. Reinforcing crossbar. Detailed Implementation

[0029] 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.

[0030] like Figure 1 , Figure 3 As shown, this embodiment of the invention provides a storage tank with a rod-type rear bottom force transmission structure, including a front bottom 1, a front short shell 4, a cylindrical section 2, a rear short shell 5, and a rear bottom 3 connected in sequence. A rod-type force transmission structure 8 is provided inside the rear bottom 3. The rod-type force transmission structure 8 includes a force transmission rod 81, a connector body 82 and a bottom plate 83 respectively fixedly connected to both ends of the force transmission rod 81. A thrust ring 32 is provided at the end of the rear bottom 3, and the bottom plate 83 is detachably connected to the thrust ring 32. The cylindrical section 2 includes an axially arranged stringer 212, and the bottom end of the stringer 212 is detachably connected to the connector body 82 (preferably by bolt connection).

[0031] As mentioned earlier, the rear bottom force transmission structure of the storage tank can improve structural efficiency. However, current rear bottom force transmission structures are all made by welding reinforcing ribs (fins), resulting in poor reliability and difficulty in inspecting weld quality. Reliability assessment of the force transmission structure is particularly challenging under repeated use. To address this issue, in this technical solution, the storage tank as a whole still consists of five parts: front bottom 1, front short shell 4, cylindrical section 2, rear short shell 5, and rear bottom 3. However, a rod-type force transmission structure 8 is used internally to replace the existing reinforcing ribs, which is significantly different from existing technologies.

[0032] 1) The main body of the force transmission structure was changed from fin-shaped welds to force transmission rods 81. The straight rods (force transmission rods 81 are arranged at an angle, but they are straight rods themselves) have higher strength, so the force they can withstand is correspondingly improved, thus improving the overall load-bearing capacity.

[0033] 2) In the prior art, the reinforcing ribs are welded to the disc-shaped rear bottom shell. In application, the thrust of the rocket engine still needs to be transmitted to the rear short shell and then to the tube section through the rear bottom shell. Therefore, the rear bottom shell itself is also prone to damage after bearing a large thrust. However, with the adoption of this technical solution, the rear end of the force transmission rod 81 is connected to the thrust ring 32, and the front end is directly connected to the stringer 212 in the tube section 2. The force transmission rod 81 does not contact the rear bottom shell 31. Therefore, the rear bottom shell 31 does not directly participate in the transmission of thrust. Compared with the relatively weak rear bottom shell 31, the strength of the stringer 212 is obviously much higher, thus avoiding the damage of the rear bottom shell 31.

[0034] 3) Since the fins are no longer installed, there is no longer a weld between the original fins and the back bottom, thus avoiding the weakening effect of local stress changes at the weld on the back bottom.

[0035] 4) The two ends of the rod-type force transmission structure 8 are connected to the stringer 212 and the thrust ring 32 by bolts. This does not involve the assessment of the quality of important load-bearing welds under multiple use conditions (the welds are prone to hidden dangers during use, and if reused, the weld quality must be accurately assessed), which helps to realize the reuse of the storage tank.

[0036] 5) Bolted connections are easier to disassemble and maintain, so even if the rod-type force transmission structure 8 needs to be replaced, it is simple and easy to do, further ensuring the feasibility of reusing the storage tank.

[0037] In practical applications, the form of the rod-type force transmission structure 8 and the cross-sectional form of the force transmission rod 81 can be adjusted according to the thrust of the rocket engine.

[0038] Furthermore, in order to maintain stress balance and improve overall load-bearing capacity, such as Figure 2 As shown, multiple sets of rod-type force transmission structures 8 need to be set (e.g., 6 sets, 8 sets, or 10 sets), and the multiple sets of rod-type force transmission structures 8 are evenly distributed around the circumference.

[0039] Furthermore, for ease of arrangement, each set of rod-type force transmission structures 8 includes multiple circumferentially arranged force transmission rods 81. The rear ends of the multiple force transmission rods 81 are fixedly connected together, that is, the rear ends of the multiple force transmission rods 81 share a base plate 83 for easy arrangement. At the same time, the front ends of the multiple force transmission rods 81 are separated and connected to different stringers 212 respectively. In this way, the force transmission rods 81 can be connected to as many stringers 212 as possible, thereby distributing the thrust evenly in the circumferential direction of the cylindrical section 2. At this time, from an overall perspective, each set of rod-type force transmission structures 8 forms a V-shaped structure, which is more compatible with the shape of the rear bottom 3 itself (the rear bottom 3 is formed by the fixed connection of the rear bottom shell 31 and the thrust ring 32, and the rear bottom shell 31 itself is also a structure whose outer diameter decreases as it gets closer to the thrust ring 32).

[0040] Furthermore, the most preferred and easiest-to-implement method is that each set of rod-type force transmission structure 8 includes three force transmission rods 81, and the three force transmission rods 81 are respectively connected to three sequentially adjacent stringers 212.

[0041] Furthermore, such as Figure 1 , Figure 2As shown, two connector bodies 82, arranged adjacently and belonging to two adjacent sets of rod-type force transmission structures 8, are connected together by a tie rod 84. That is, in each set of rod-type force transmission structures 8, the force transmission rods 81 located on both sides can be connected to the force transmission rods 81 in other adjacent sets on the same side via the tie rod 84, while the force transmission rod 81 located in the middle is set separately and not connected to the top of other force transmission rods 81. The introduction of this tie rod 84 allows adjacent sets of rod-type force transmission structures 8 to be connected and mutually supported, thereby improving stability. In addition, considering that the rod-type force transmission structure 8 can be disassembled inside the tank and removed from the narrow manhole in the reusable state, the tie rod 84 and the connector body 82 are bolted together.

[0042] Furthermore, as shown above, the middle force transmission rod 81 cannot be horizontally fixed by the tie rod 84. Therefore, a reinforcing crossbar 85 can be installed inside the group so that the middle force transmission rod 81 can be connected to the other two force transmission rods 81 in the group.

[0043] Furthermore, in existing skin-framed storage tanks, each stringer is welded to the skin. Extensive use of welding leads to poor structural reliability, very long weld lengths, long weld inspection cycles, and difficulties in assessing weld quality. This problem is also a significant factor limiting the reusability of the storage tanks. Therefore, such as... Figure 4 , Figure 5 As shown, in this technical solution, the existing method of welding the stringers and skin is no longer used. Instead, the skin 211 and stringers 212 are integrally formed to form an arc-shaped cylindrical segment 21. Then, multiple circumferentially distributed cylindrical segments 21 (the number of cylindrical segments 21 can be 6 to 18 depending on the size of the tank) are spliced ​​together and connected with longitudinal welds 6 to form a cylindrical section 2. At the same time, the two ends of the cylindrical section 2 are connected to the front short shell 4 and the rear short shell 5 respectively through circumferential welds 7, thus forming the entire tank. Although welds still exist in this method, the number of longitudinal welds 6 is far less than that in the existing technology, thus greatly reducing the workload of weld inspection and improving the accuracy of weld quality assessment.

[0044] Furthermore, to facilitate processing and improve strength, the cylindrical segment 21 can be made of aluminum alloy using hot extrusion molding. Its cross-sectional dimensions can be adjusted according to the load conditions. The stringers 212 can be T-shaped or Z-shaped, etc. Figure 6 As shown.

[0045] In one embodiment, the forming process of the cylindrical segment 21 is as follows: 1) Heating the casting rod, selecting the heating temperature according to the grade, generally between 450℃ and 530℃; 2) Hot extrusion and quenching, after the extruded blank is demolded, it is quenched with water to room temperature within 25 seconds; 3) The quenched wall plate (i.e., the cylindrical segment 21) is stretched, with a stretching elongation between 1.5 and 2.5; 4) The stretched product is artificially aged.

[0046] Furthermore, to improve circumferential stiffness, an intermediate frame 22 is installed at intervals along the axial direction inside the cylinder section 2 to provide reinforcement. The intermediate frame 22 is formed by traditional tension bending process, and its cross-sectional shape can be referenced. Figure 7 To avoid the adverse effects of welding, the intermediate frame 22 and the stringer 212 are connected by riveting or bolting.

[0047] This invention also provides a launch vehicle, including a rocket engine and a propellant tank with a rod-type rear bottom force transmission structure as described above; the rocket engine is connected to the thrust ring 32 via a connecting frame.

[0048] In the above detailed description, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features of the single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0049] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0050] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A storage tank with a rod-type rear bottom force transmission structure, characterized in that, It includes a front bottom (1), a front short shell (4), a cylindrical section (2), a rear short shell (5) and a rear bottom (3) connected in sequence, and a rod-type force transmission structure (8) is provided inside the rear bottom (3); The rod-type force transmission structure (8) includes a force transmission rod (81), a connector body (82) and a base plate (83) respectively fixedly connected to both ends of the force transmission rod (81); a thrust ring (32) is provided at the end of the rear bottom (3), and the base plate (83) is detachably connected to the thrust ring (32); the cylindrical section (2) includes an axially arranged stringer (212), and the bottom end of the stringer (212) is detachably connected to the connector body (82).

2. The storage tank with a rod-type rear bottom force transmission structure as described in claim 1, characterized in that, The rod-type force transmission structure (8) has multiple sets, and the multiple sets of the rod-type force transmission structure (8) are evenly distributed circumferentially.

3. The storage tank with a rod-type rear bottom force transmission structure as described in claim 2, characterized in that, Each set of the rod-type force transmission structure (8) includes multiple circumferentially arranged force transmission rods (81), the rear ends of the multiple force transmission rods (81) are fixedly connected together, and the front ends of the multiple force transmission rods (81) are respectively connected to different stringers (212).

4. The storage tank with a rod-type rear bottom force transmission structure as described in claim 3, characterized in that, Each set of the rod-type force transmission structure (8) includes three force transmission rods (81), and the three force transmission rods (81) are respectively connected to three adjacent stringers (212).

5. The storage tank with a rod-type rear bottom force transmission structure as described in claim 4, characterized in that, The two joint bodies (82) of the two adjacent rod-type force transmission structures (8) are connected together by a tie rod (84).

6. The storage tank with a rod-type rear bottom force transmission structure as described in claim 4, characterized in that, In each of the rod-type force transmission structures (8), a reinforcing crossbar (85) is also provided between two adjacent force transmission rods (81).

7. The storage tank with a rod-type rear bottom force transmission structure as described in claim 1, characterized in that, The cylindrical segment (2) is spliced ​​together from multiple circumferentially distributed cylindrical segments (21); the cylindrical segment (21) includes an arc-shaped plate-like skin (211) and multiple stringers (212), the stringers (212) being fixedly connected to the inner side of the skin (211).

8. The storage tank with a rod-type rear bottom force transmission structure as described in claim 7, characterized in that, The cylindrical segment (21) is an integral structure made by extrusion molding.

9. The storage tank with a rod-type rear bottom force transmission structure as described in claim 7, characterized in that, The inner side of the cylindrical section (2) is also coaxially provided with multiple annular intermediate frames (22). The outer side of the intermediate frame (22) is in contact with the inner side of the stringer (212), and the intermediate frame (22) is detachably connected to the stringer (212).

10. A launch vehicle, characterized in that, It includes a rocket engine and a storage tank with a rod-type rear bottom force transmission structure as described in any one of claims 1-9; the rocket engine is connected to the thrust ring (32) via a connecting frame.

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