Double-layer common bottom structure

Abstract

The present invention provides a double-layer common bottom structure, comprising a first common bottom, a second common bottom, a Y-shaped ring, and a gasket; the first common bottom and the second common bottom are both hemispherical structures and are arranged concentrically from the inside out; a first gap is provided between the first common bottom and the second common bottom; the size of the first gap is 0.1 to 0.5 mm; a stress relief groove is provided in the Y-shaped ring, the stress relief groove being connected to the first gap; a gasket is provided in the stress relief groove; the thickness of the gasket is 0.05 to 0.20 mm smaller than the width of the stress relief groove of the Y-shaped ring. The present invention achieves a double-layer redundant design of the common bottom of a common bottom tank through the design of the first and second common bottoms. If the first or second common bottom leaks, the propellant leaks into the gap between the first and second common bottoms. The unleaked common bottom still serves to physically isolate the two propellants, thereby solving the safety problem of using a common bottom tank.

Description

Technical Field

[0001] The present invention relates to the field of aerospace liquid propulsion technology, and in particular to a double-layer common bottom structure. Background Art

[0002] To fully utilize the space within the intertank sections and save weight, common-bottom tanks are currently widely used in the launch vehicle industry. With the development of manned spaceflight, there are increasing demands for lighter tanks and higher emission efficiency. This also places a higher demand on the tank's center of mass, with the goal of lowering the vehicle's center of mass by reducing the tank's center of mass. Consequently, there is a demand for common-bottom tanks in the manned spaceflight industry. There are significant differences in operating pressures and duty cycles between tanks in the manned spaceflight industry and those in the launch vehicle industry. Manned spaceflight tanks generally operate at pressures of 2.0 MPa or higher, with a service life of more than one year. Launch vehicle tanks operate at lower pressures, typically 0.5 MPa to 0.8 MPa, during the launch vehicle's ascent phase, and for shorter service lives. Currently, common-bottom tanks in the launch vehicle industry generally utilize a single-layer bottom structure. If this single-layer bottom structure is damaged, the two different substances, originally stored separately within the common bottom tank, will mix, posing a significant safety hazard.

[0003] Patent document CN109911247A discloses a rocket and its propellant tank, comprising a first tank, a second tank, and a shared tank bottom. The first tank and the second tank are connected via the shared tank bottom, and the shared tank bottom forms a closed structure with the connection between the first tank and the second tank. The rocket and its propellant tank provided by this invention eliminate the series structure of the inter-tank sections, which can effectively shorten the rocket body height and reduce the slenderness ratio of the launch vehicle, which is beneficial for increasing the stability of the rocket. The rocket has the lightest weight, the highest space utilization, and the largest carrying capacity. However, this solution still uses the traditional standard tank bottom component, namely a single-layer bottom structure, which still poses a significant safety hazard if the single-layer bottom structure is damaged. Summary of the Invention

[0004] In view of the defects in the prior art, the present invention aims to provide a double-layer common bottom structure.

[0005] According to the present invention, a double-layer common bottom structure is provided, comprising a first common bottom, a second common bottom, a Y-shaped ring and a gasket ring;

[0006] The first common bottom and the second common bottom are both hemispherical structures and are concentrically arranged from the inside to the outside;

[0007] A first gap is provided between the first common bottom and the second common bottom; the size of the first gap is 0.1 to 0.5 mm;

[0008] The end of the first common bottom and the end of the second common bottom are connected through a Y-shaped ring, and the end of the first common bottom and the end of the second common bottom are respectively welded to both sides of the Y-shaped ring;

[0009] A stress relief groove is provided in the Y-shaped ring, and the stress relief groove is communicated with the first gap;

[0010] A gasket is provided in the stress relief groove, one end of the gasket is located in the stress relief groove, and the other end passes through the stress relief groove and extends to the first gap;

[0011] The thickness of the gasket is 0.05 to 0.20 mm smaller than the width of the stress release groove of the Y-shaped ring.

[0012] Preferably, the diameter of the outer surface of the first common bottom is 2400 mm, and the diameter of the inner surface of the second common bottom is 2400.1 to 2400.5 mm;

[0013] The ratio of the thickness to the diameter of the first common bottom and the ratio of the thickness to the diameter of the second common bottom are both less than 0.0005.

[0014] Preferably, the material of the first common bottom is aluminum or aluminum alloy;

[0015] The material of the second common bottom is aluminum or aluminum alloy;

[0016] Preferably, the stress relief groove is a U-shaped structure, and the width t of the stress relief groove is 2.5 to 3.5 mm.

[0017] Preferably, the weld between the Y-shaped ring and the first common bottom is defined as the first weld, and the distance h2 between the first weld and the root of the stress relief groove is 25 to 35 mm;

[0018] The weld between the Y-shaped ring and the second common bottom is defined as the second weld, and the distance h1 between the second weld and the root of the stress relief groove is 20 to 30 mm;

[0019] The distance between the first weld and the second weld is not less than 9 mm.

[0020] Preferably, the Y-shaped ring is further provided with a detection interface, and the detection interface is communicated with the stress release groove.

[0021] Preferably, the detection interface is in a stepped shape, including a first step, a second step, a third step, a fourth step, and a fifth step, the diameters of which increase in sequence and are connected in sequence;

[0022] The first step is a through-hole structure and is connected to the stress release groove;

[0023] The second and third stages are threaded hole structures;

[0024] The fourth and fifth steps are hole structures.

[0025] Preferably, the diameter D1 of the first step is 2.0-2.5 mm;

[0026] The second and third steps are threaded holes of M3 and M4 sizes respectively

[0027] The diameter D2 of the fourth stage is 4.0-4.5 mm;

[0028] The diameter D3 of the fifth step is 6.0 to 9.0 mm.

[0029] Preferably, the material of the backing ring is aluminum or aluminum alloy.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention realizes a double-layer redundant design of the common bottom of the common bottom tank through the design of the first common bottom and the second common bottom. After the first common bottom or the second common bottom leaks, the propellant leaks into the gap between the first common bottom and the second common bottom. The common bottom that has not leaked still plays the role of physical isolation of the two propellants, solving the safety problem of the use of the common bottom tank.

[0032] 2. The present invention provides a test interface, so that the sealing performance of the first common bottom and the second common bottom can be tested during the tank production test phase, thereby further improving the safety performance of the tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0034] Figure 1 It is a structural schematic diagram of the present invention;

[0035] Figure 2 It is a structural schematic diagram of A of the present invention;

[0036] Figure 3 for Figure 2 Dimensional diagram.

[0037] The figure shows:

[0038] DETAILED DESCRIPTION

[0039] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0040] The present invention provides a double-layer common bottom structure, comprising a first common bottom 1, a second common bottom 2, a Y-shaped ring 3, and a gasket 4. In a preferred embodiment, the gasket 4 is made of aluminum or aluminum alloy with grades 1035, 1050 or 1060.

[0041] The first common bottom 1 and the second common bottom 2 are both thin-walled hemispherical structures and are arranged concentrically from the inside to the outside; a first gap 7 is provided between the first common bottom 1 and the second common bottom 2; the size of the first gap 7 is 0.1 to 0.5 mm; the first gap 7 is the gap between the outer surface of the first common bottom 1 and the inner surface of the second common bottom 2.

[0042] The end of the first common bottom 1 and the end of the second common bottom 2 are connected through a Y-shaped ring 3, and the end of the first common bottom 1 and the end of the second common bottom 2 are respectively welded on both sides of the Y-shaped ring 3; preferably, the end of the first common bottom 1 and the end of the second common bottom 2 are respectively stir-friction welded on both sides of the Y-shaped ring 3.

[0043] A stress relief groove 5 is provided in the Y-shaped ring 3. Preferably, the stress relief groove 5 is a U-shaped groove. The stress relief groove 5 is connected to the first gap 7. A gasket 4 is provided in the stress relief groove 5. One end of the gasket 4 is located in the stress relief groove 5, and the other end extends through the stress relief groove 5 to the first gap 7. In a preferred embodiment, the other end of the gasket 4 only slightly exceeds the connection between the first common bottom 1 and the Y-shaped ring 3, or the other end of the gasket 4 is flush with the connection between the first common bottom 1 and the Y-shaped ring 3. Specifically, the other end of the gasket 4 only slightly exceeds the first weld 8, or the other end of the gasket 4 is flush with the first weld 8. The thickness of the gasket 4 located in the stress relief groove 5 is 0.05 to 0.20 mm smaller than the width of the stress relief groove of the Y-shaped ring 3. The gaps between the gasket 4 extending to the first gap 7 and the first common bottom 1 and the second common bottom 2 are both 0.05 to 0.20 mm. Under external pressure, the first and second common bottoms near the first weld 8 come into contact with the gaskets, which are used to transfer balance. In a preferred embodiment, the gasket 4 is a split structure, and the gasket 4 is designed to conform to the stress relief groove 5 of the Y-ring 3. After the first common bottom 1 and the Y-ring 3 are welded, the gasket 4 is assembled into the stress relief groove 5 of the Y-ring 3. For example, the split gasket 4 can be assembled into the stress relief groove via the detection interface 6.

[0044] The outer diameter of the first common bottom 1 is 2400 mm, the inner diameter of the second common bottom 2 is 2400.1 to 2400.5 mm, and the ratio of the thickness to the diameter of the first common bottom 1 and the ratio of the thickness to the diameter of the second common bottom 2 are both less than 0.0005.

[0045] The material of the first common bottom 1 is aluminum or aluminum alloy material; preferably, the first common bottom 1 is aluminum or aluminum alloy with a grade of 5A06, 5B70, 2219 or 2195, and the material of the second common bottom 2 is aluminum or aluminum alloy material; preferably, the second common bottom 2 is aluminum or aluminum alloy with a grade of: 1035, 1050 or 1060.

[0046] The stress relief groove 5 is a U-shaped structure with a width t of 2.5 to 3.5 mm. The weld between the Y-shaped ring 3 and the first common bottom 1 is a first weld 8, and the distance h2 between the first weld 8 and the root of the stress relief groove is 25 to 35 mm.

[0047] The weld between the Y-shaped ring 3 and the second common bottom 2 is the second weld 9, and the distance h1 between the second weld 9 and the root of the stress relief groove is 20 to 30 mm;

[0048] The distance between the first weld 8 and the second weld 9 is not less than 9 mm.

[0049] The Y-shaped ring 3 is also provided with a detection interface 6, which is connected to the stress relief groove 5. The detection interface 6 can be used to detect the sealing performance of the welds of the first common bottom 1 and the second common bottom 2. The detection interface is stepped, including a first step 61, a second step 62, a third step 63, a fourth step 64, and a fifth step 65, which have successively increasing diameters and are connected in sequence.

[0050] The first step 61 is a through-hole structure and communicates with the stress relief groove 5; the second and third steps 62 and 63 are threaded holes; the fourth and fifth steps 64 and 65 are holes. The diameter D1 of the first step 61 is 2.0 to 2.5 mm; the second and third steps 62 and 63 are M3 and M4 threaded holes, respectively; the diameter D2 of the fourth step 64 is 4.0 to 4.5 mm; and the diameter D3 of the fifth step 65 is 6.0 to 9.0 mm.

[0051] In a preferred example, the number of the detection interfaces 6 is 4 to 8, and they are evenly arranged in the circumferential direction of the Y-shaped ring 3 .

[0052] The first and second common bottoms of the present invention are spherical structures with a diameter of 2400mm. The first and second common bottoms are designed to match each other, achieving a double-layer redundancy design for the common bottom tank. If a leak occurs in either the first or second common bottom, the propellant leaks into the gap between the first and second common bottoms. The remaining common bottom still physically isolates the two propellants, thus addressing the safety issues associated with common bottom tanks. Furthermore, the Y-shaped ring test interface of the present invention allows for the sealing of the first and second common bottoms to be tested during tank production and testing. This double-layer common bottom structure addresses the safety and testability issues associated with bicomponent common bottom tanks, significantly enhancing their application.

[0053] The present invention solves the problems of safety and test coverage in the use of dual-component common-bottom tanks, and realizes the design requirement of "one-fault operation and secondary-fault safety" for manned aircraft. The double-layer common-bottom structure described in the present invention can be widely used in common-bottom tanks in the fields of launch vehicles, deep space exploration, manned lunar landing, etc., and can effectively improve the reliability and safety of tanks and aircraft.

[0054] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0055] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A double-layer common bottom structure, characterized in that: It comprises a first common bottom (1), a second common bottom (2), a Y-shaped ring (3) and a gasket ring (4); The first common bottom (1) and the second common bottom (2) are both hemispherical structures and are arranged concentrically from the inside to the outside; A first gap (7) is provided between the first common bottom (1) and the second common bottom (2); the size of the first gap (7) is 0.1-0.5 mm; The end of the first common bottom (1) and the end of the second common bottom (2) are connected via a Y-shaped ring (3), and the end of the first common bottom (1) and the end of the second common bottom (2) are respectively welded to both sides of the Y-shaped ring (3); A stress release groove (5) is provided in the Y-shaped ring (3), and the stress release groove (5) is connected to the first gap (7); A gasket (4) is provided in the stress release groove (5), one end of the gasket (4) is located in the stress release groove (5), and the other end passes through the stress release groove (5) and extends to the first gap (7); The thickness of the gasket (4) is 0.05-0.20 mm smaller than the width of the stress release groove (5) of the Y-shaped ring (3); The Y-shaped ring (3) is further provided with a detection interface (6), and the detection interface (6) is connected to the stress release groove (5); The detection interface is in a stepped shape, including a first step (61), a second step (62), a third step (63), a fourth step (64), and a fifth step (65) whose diameters increase in sequence and are connected in sequence; The first step (61) is a through-hole structure and is connected to the stress release groove (5); The second stage (62) and the third stage (63) are threaded hole structures; The fourth step (64) and the fifth step (65) are hole structures.

2. The double-layer common bottom structure according to claim 1, characterized in that: The outer surface diameter of the first common bottom (1) is 2400 mm, and the inner surface diameter of the second common bottom (2) is 2400.1 to 2400.5 mm; The ratio of the thickness to the diameter of the first common bottom (1) and the ratio of the thickness to the diameter of the second common bottom (2) are both less than 0.0005.

3. The double-layer common bottom structure according to claim 1, characterized in that: The material of the first common bottom (1) is aluminum or aluminum alloy; The material of the second common bottom (2) is aluminum or an aluminum alloy material.

4. The double-layer common bottom structure according to claim 1, characterized in that: The stress release groove (5) is a U-shaped structure, and the width t of the stress release groove (5) is 2.5-3.5 mm.

5. The double-layer common bottom structure according to claim 1, characterized in that: The weld between the Y-shaped ring (3) and the first common bottom (1) is defined as a first weld (8), and the distance h2 between the first weld (8) and the root of the stress relief groove is 25 to 35 mm; The weld between the Y-shaped ring (3) and the second common bottom (2) is defined as a second weld (9), and the distance h1 between the second weld (9) and the root of the stress relief groove is 20 to 30 mm; The distance between the first weld (8) and the second weld (9) is not less than 9 mm.

6. The double-layer common bottom structure according to claim 1, characterized in that: The first step (61), the diameter D1 of the first step (61) is 2.0~2.5mm; The second stage (62) and the third stage (63) are threaded holes of M3 and M4 sizes respectively. The diameter D2 of the fourth stage (64) is 4.0-4.5 mm; The diameter D3 of the fifth stage (65) is 6.0~9.0mm.

7. The double-layer common bottom structure according to claim 1, characterized in that: The material of the backing ring (4) is aluminum or aluminum alloy.

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