Long-focus coaxial space camera bearing cylinder structure

Abstract

The invention relates to the technical field of space optical remote sensing, in particular to a long-focus coaxial space camera bearing cylinder structure which comprises a cylinder body, a T-shaped ring rib and a front frame, and the cylinder body is divided into a main body area, a bottom thickening area and a top thickening area; the T-shaped ring ribs are uniformly distributed along the axial direction of the main body area; the front frame is embedded in the top thickening area. The bearing cylinder has the advantages that the bearing cylinder is made of the carbon fiber composite material, the cylinder body is of a thin-wall structure, under the condition of the same size, the overall isostatic rigidity (deformation under the action of 500kg force) is equivalent to that of titanium alloy, and the weight is reduced by 63%. Through the laying structure of the cylinder body, the T-shaped ring rib and the front frame, the linear expansion coefficients of the connecting parts are matched, and stress concentration is avoided.

Description

Technical Field

[0001] The present invention relates to the field of space optical remote sensing technology, and particularly to a load-bearing cylinder structure of a long-focus coaxial space camera. Background Art

[0002] The long-focus coaxial space camera is a core equipment for deep space exploration and high-resolution earth observation. Its optical system usually consists of a primary mirror, a secondary mirror, a tertiary mirror, and a detector, etc. Among them, the primary mirror, the tertiary mirror, and the detector are usually installed on the base at the bottom of the camera, while the secondary mirror is installed on the radial support beam at the top of the camera. Connection and load transfer need to be achieved through the fuselage between the two. The fuselage of the base and the radial support beam is one of the key components of the camera, which is used to ensure the stable and reliable spatial position relationship between the primary mirror and the secondary mirror, thereby ensuring the imaging quality of the camera.

[0003] There are mainly two common fuselage configurations: truss structure and thin-walled load-bearing cylinder structure. Due to the advantages of high stiffness, high strength, high thermal stability, etc., the load-bearing cylinder structure has been widely used in space cameras. However, traditional load-bearing cylinders mostly use metal materials (such as aluminum alloy, titanium alloy) and are strengthened by equally spaced ring ribs or longitudinal ribs. This design has the following problems: Excessive weight: The density of metal materials is high, and the design of thick walls or dense ribs is difficult to meet the lightweight requirements.

[0004] Sensitive to thermal deformation: The linear expansion coefficient (CTE) of metal materials is relatively high, and the change of space temperature is likely to cause the optical axis to shift. Summary of the Invention

[0005] In view of this, the present invention aims to provide a load-bearing cylinder structure of a long-focus coaxial space camera. The load-bearing cylinder is made of carbon fiber composite material through a winding molding process, effectively reducing the weight of the load-bearing cylinder. By designing the layup of the cylinder body, T-shaped ring ribs, and front frame, the thermal stress caused by temperature change can be avoided.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows: A load-bearing cylinder structure of a long-focus coaxial space camera, comprising: a cylinder body, which includes a top thickening area, a main body area, and a bottom thickening area distributed axially; T-shaped ring ribs, which are evenly distributed axially along the inner wall of the main body area; and a front frame, which is embedded in the top thickening area.

[0007] Further, the main body area is in the shape of a conical cylinder; the top thickening area extends upward axially and gradually expands from the top of the main body area, and the wall thickness of the top thickening area increases along the extension direction; the bottom thickening area extends downward axially and gradually expands from the bottom of the main body area, and the wall thickness of the bottom thickening area increases along the extension direction.

[0008] Further, the cylinder body, the T-shaped ring ribs, and the front frame are all formed by winding carbon fiber composite materials.

[0009] Furthermore, the ply structure of the main body area is [90 / +54 / 0 / -54 / 90]2s; the ply structure of the bottom thickened area is [90 / +54 / 0 / -54 / 90 / 0 / 90 / 0 / +54 / 0 / -54 / 0 / 90]s; the ply structure of the top thickened area is [903 / +54 / 0 / -54 / 903 / +54 / 0 / -54 / 90] s 。

[0010] Furthermore, the ply structure of the T-shaped ring rib is [90 / +54 / 0 / -54 / 90]3.

[0011] Furthermore, the ply structure of the front frame is [90 / +45 / 90 / -45 / 90]8.

[0012] Furthermore, the T-shaped ring rib includes a cylindrical base body and reinforcing ribs extending radially inwards along the inner wall of the cylindrical base body, and the radial width of the reinforcing ribs is 2 to 3 times the height of the cylindrical base body.

[0013] Furthermore, the distance between two adjacent T-shaped ring ribs is 1 / 10 to 1 / 5 of the diameter of the cylindrical base body.

[0014] Furthermore, the front frame includes a C-shaped frame and radial ribs, and the radial ribs are evenly distributed radially within the C-shaped frame.

[0015] Furthermore, the number of radial ribs is 6 to 12.

[0016] The present invention can achieve the following beneficial effects: 1) Lightweight design: The load-bearing cylinder of the present invention is made of carbon fiber composite material. The cylinder body is a thin-walled structure, and the reinforcing ribs adopt the structure of T-shaped ring ribs, so that the overall static stiffness (deformation under the action of 500 kg force) of the load-bearing cylinder is equivalent to that of titanium alloy under the same volume condition, and the weight is reduced by 63%; 2) Low overload stress: Under the overload working condition, the evaluation value (Tsai-Wu value) of the Tsai-Wu failure criterion of the load-bearing cylinder is less than 0.1, meeting the high reliability requirements.

[0017] 3) Low thermal stress: Within the working temperature range, the Tsai-Wu value of the connection area between the cylinder body and the front frame is less than 0.02, effectively avoiding the failure risk caused by thermal stress.

[0018] 4) Good processability: The structure forming process is simple, easy to assemble, and suitable for mass production.

[0019] 5) Through the ply structures of the cylinder body, T-shaped ring ribs and front frame, the linear expansion coefficients of the connection parts are adapted to each other, avoiding stress concentration.

[0020] 6) The T-shaped ring rib combines the functions of structural reinforcement and diaphragm, meeting the light-shielding requirement of the optical system while enhancing the stiffness. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not unduly limit the present invention. In the drawings: Figure 1 is an axial sectional view of the load-bearing cylinder structure of the long focal length coaxial space camera provided according to an embodiment of the present invention; Figure 2 is provided according to an embodiment of the present invention Figure 1 a partial enlarged view of the part at A (the connection part between the cylinder and the front frame) in Figure 3 is provided according to an embodiment of the present invention Figure 1 a partial enlarged view of the part at B (the connection part between the cylinder and the T-shaped ring rib) in Figure 4 is an axial sectional view of the cylinder provided according to an embodiment of the present invention; Figure 5 is provided according to an embodiment of the present invention Figure 4 a partial enlarged view of the part at C (the top thickened area) in Figure 6 is provided according to an embodiment of the present invention Figure 4 a partial enlarged view of the part at D (the bottom thickened area) in Figure 7 is an axial sectional view of the T-shaped ring rib provided according to an embodiment of the present invention; Figure 8 is an axial sectional view of the front frame provided according to an embodiment of the present invention; Figure 9 is provided according to an embodiment of the present invention Figure 8 a sectional view along E-E.

[0022] The reference numerals include: 1, cylinder; 11, main body area; 12, top thickened area; 13, bottom thickened area; 2, T-shaped ring rib; 21, cylindrical base; 22, reinforcing rib; 3, front frame; 31, C-shaped frame; 32, radial rib. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the present invention.

[0024] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the technical features indicated. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0026] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0027] The present invention will be described in detail below with reference to the embodiments.

[0028] As Figures 1 to 9 shown, a force-bearing cylinder structure of a long-focus coaxial space camera provided by an embodiment of the present invention includes: a cylinder body 1, a T-shaped ring rib 2, and a front frame 3. The T-shaped ring rib 2 is uniformly distributed along the axial direction of the cylinder body 1 on the inner wall of the cylinder body 1, and the front frame 3 is embedded at the top of the cylinder body 1. The cylinder body 1, the T-shaped ring rib 2, and the front frame 3 are all formed by winding carbon fiber composite materials.

[0029] The cylinder body 1 is divided into a main body area 11, a top thickening area 12, and a bottom thickening area 13. The main body area 11 is in the shape of a conical cylinder with a wall thickness of 2 mm. Among them, the top thickening area 12 extends upward axially from the top of the main body area 11 in a gradually expanding manner, and the wall thickness of the top thickening area 12 increases along the extending direction. The bottom thickening area 13 extends downward axially from the bottom of the main body area 11 in a gradually expanding manner, and the wall thickness of the bottom thickening area 13 increases along the extending direction.

[0030] Specifically, the main body area 11 is a low-axial linear expansion area, and the ply structure of the main body area 11 is [90 / +54 / 0 / -54 / 90]2s. This ply design can effectively suppress axial thermal deformation, thereby ensuring a stable relative position relationship between the primary mirror and the secondary mirror of the space camera when the temperature changes.

[0031] The top thickened area 12 is connected to the front frame 3. The ply structure of the top thickened area 12 is [903 / +54 / 0 / -54 / 903 / +54 / 0 / -54 / 90]s to match the radial linear expansion coefficient of the front frame 3 and avoid stress concentration. This ply can regulate the distribution of thermal stress when the temperature changes and improve the structural reliability.

[0032] The bottom thickened area 13 is connected to the metal base of the space camera. The ply structure of the bottom thickened area 13 is [90 / +54 / 0 / -54 / 90 / 0 / 90 / 0 / +54 / 0 / -54 / 0 / 90]s to match the radial linear expansion coefficient of the metal base and avoid stress concentration. This ply can regulate the distribution of thermal stress when the temperature changes and improve the structural reliability.

[0033] The T-shaped ring rib 2 includes a cylindrical matrix 21 and a reinforcing rib 22 extending radially inward along the inner wall of the cylindrical matrix 21. The radial width of the reinforcing rib 22 is 2 to 3 times the height of the cylindrical matrix 21. The distance between two adjacent T-shaped ring ribs 2 is 1 / 10 to 1 / 5 of the diameter of the cylindrical matrix 21. The T-shaped ring rib 2 not only meets the requirement of enhancing stiffness but also has the function of a diaphragm. The T-shaped ring rib 2 and the main body area 11 are connected by a combined adhesive and screw connection. The combined adhesive and screw connection is a hybrid connection method that combines adhesive bonding and mechanical fastening with bolts / screws, and has the advantages of both, and is commonly used in structures with high requirements for connection strength, sealing performance, and fatigue resistance.

[0034] The number of T-shaped ring ribs 2 is 3 - 6. In this embodiment, the number of T-shaped ring ribs 2 is 4.

[0035] The ply structure of the T-shaped ring rib 2 is [90 / +54 / 0 / -54 / 90]3 to make the radial linear expansion coefficient of the T-shaped ring rib 2 match that of the main body area 11.

[0036] The front frame 3 includes a C-shaped frame 31 and radiation ribs 32. The radiation ribs 32 are evenly distributed radially within the C-shaped frame 31. The number of radiation ribs 32 is 6 to 12. In this embodiment, the number of radiation ribs 32 is 12. The C-shaped frame 31 is connected to the top thickened area 12 by a combined adhesive and screw connection.

[0037] The ply structure of the front frame 3 is [90 / +45 / 90 / -45 / 90]8 to match the radial linear expansion coefficient of the front frame 3 with that of the top thickened area 12.

[0038] Specifically, the C-shaped frame 31 includes a cylinder and two circular rings. The two circular rings are respectively connected to the two ends of the cylinder. The radial ribs 32 are rectangular plates. The radial ribs 32 are evenly distributed radially between the two circular rings along the circumferential direction of the circular rings. One long side of each radial rib 32 is connected to the inner wall of the cylinder, and the other two short sides are respectively connected to the two circular rings.

[0039] Mechanical load analysis: Using finite element simulation analysis software, an overload load of 10 times the gravitational acceleration is applied to the load-bearing cylinder in three mutually perpendicular directions. The simulation results show that the evaluation values of the Tsai-Wu (Tsai-Wu Failure Criterion) failure criterion of the load-bearing cylinder under each working condition are all less than 0.1.

[0040] Thermal load analysis: Under the condition of a uniform temperature rise load of +5°C, the finite element analysis shows that the Tsai-Wu value in the connection area between the load-bearing cylinder and the metal base is less than 0.02.

[0041] The above specific implementation manners do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A load-bearing cylinder structure for a long focal length coaxial space camera, characterized in that, Comprising: A cylinder body, which includes a top thickening area, a main body area, and a bottom thickening area distributed axially; T-shaped ring ribs, which are evenly distributed axially along the inner wall of the main body area; A front frame, which is embedded in the top thickening area.

2. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 1, characterized in that, The main body area is in the shape of a conical cylinder; the top thickening area extends axially upward and gradually expands from the top of the main body area, and the wall thickness of the top thickening area increases along the extension direction; the bottom thickening area extends axially downward and gradually expands from the bottom of the main body area, and the wall thickness of the bottom thickening area increases along the extension direction.

3. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 1, characterized in that, The cylinder body, the T-shaped ring ribs, and the front frame are all formed by winding carbon fiber composite materials.

4. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 3, characterized in that, The ply structure of the main body area is [90 / +54 / 0 / -54 / 90]2s; the ply structure of the bottom thickening area is [90 / +54 / 0 / -54 / 90 / 0 / 90 / 0 / +54 / 0 / -54 / 0 / 90]s; the ply structure of the top thickening area is [903 / +54 / 0 / -54 / 903 / +54 / 0 / -54 / 90]s.

5. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 3, characterized in that The ply structure of the T-shaped ring ribs is [90 / +54 / 0 / -54 / 90]3.

6. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 3, characterized in that, The ply structure of the front frame is [90 / +45 / 90 / -45 / 90]8.

7. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 1, wherein The T-shaped ring ribs include a cylindrical matrix and reinforcing ribs extending radially inward along the inner wall of the cylindrical matrix, and the radial width of the reinforcing ribs is 2 to 3 times the height of the cylindrical matrix.

8. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 7, characterized in that The distance between two adjacent T-shaped ring ribs is 1 / 10 to 1 / 5 of the diameter of the cylindrical matrix.

9. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 1, characterized in that, The front frame includes a C-shaped frame and radial ribs, and the radial ribs are evenly distributed radially within the C-shaped frame.

10. The load-bearing cylinder structure of the long focal length coaxial space camera according to claim 9, characterized in that, The number of the radial ribs is 6 to 12.

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