Carbon fiber composite material secondary mirror light shield and forming die thereof

Abstract

The invention provides a carbon fiber composite material secondary mirror light shield and a forming mold thereof, and belongs to the technical field of fiber reinforced resin matrix composite materials. The problems that a traditional alloy light shield is complex in manufacturing process, long in forming period and incapable of giving consideration to low self weight and high stability are solved. The carbon fiber composite material secondary mirror light shield and the forming die thereof are included, the light shield is made of a carbon fiber composite material, the whole light shield is of a structure with multiple layers of cylindrical thin walls, and the multiple layers of cylindrical thin walls are connected through vertical ribs. The mold comprises a mold shell and a core mold, the core mold is arranged in the mold shell, and the carbon fiber composite material secondary mirror light shield is processed through a metal mold pressing technology and a hot melting prepreg laying technology. The non-imaging stray light blocking device is mainly used for blocking non-imaging stray light in a space environment in a satellite space camera.

Description

Technical Field

[0001] The invention belongs to the field of fiber-reinforced resin-based composite materials, and in particular relates to a carbon fiber composite secondary mirror sunshade and a molding die thereof. Background Art

[0002] In a camera, the lens is divided into a primary mirror and a secondary mirror. The secondary mirror is usually located behind the primary mirror. The primary mirror is responsible for collecting light and forming an image. The function of the secondary mirror is to further reflect or adjust the light to ensure that the light can be accurately focused on the imaging sensor. Failure to use a lens hood will produce a halo, which will make the picture dim or cause flare. Therefore, a lens hood is needed to suppress the halo of the picture and prevent stray light from entering the lens. The lens hood includes a primary mirror lens hood and a secondary mirror lens hood. The secondary mirror lens hood will cause a certain amount of obstruction to the imaging light beam. In order to reduce the impact of the obstruction of the secondary mirror lens hood on the imaging quality, the obstruction ratio of the secondary mirror lens hood needs to be as small as possible. At the same time, since the secondary mirror lens hood is installed on the secondary mirror assembly, the weight of the secondary mirror lens hood is required to be as small as possible to avoid deformation of the secondary mirror assembly caused by excessive load, affecting the camera imaging quality.

[0003] The secondary mirror sunshade is crucial to the stable operation of satellite space cameras. In addition to blocking non-imaging stray light in the space environment, it must also withstand mechanical effects such as impact and vibration during satellite transportation and launch. Currently, there are two types of sunshade materials for satellite space cameras: metal materials and composite materials. Traditional metal sunshade structures often cannot take into account both low dead weight and high stability, and the manufacturing process is complex and the molding cycle is long.

[0004] Carbon fiber composite materials are widely used in the aerospace field because of their high stiffness characteristics. They can effectively reduce the weight of structural parts. The mechanical properties of carbon fiber composite materials are very strong and can be customized according to the actual use requirements and environmental conditions of the product. The composite structure of resin and carbon fiber can create composite materials with different shapes and properties. By adjusting the layering procedure, carbon fiber composite products with zero expansion coefficient can be manufactured, and their dimensional stability is even better than that of traditional metal materials. Summary of the invention

[0005] In view of this, the present invention aims to provide a carbon fiber composite secondary mirror sunshade and a molding die thereof to solve the problems of heavy weight, low strength, complex manufacturing process and long manufacturing cycle of the sunshade.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a carbon fiber composite secondary mirror hood, the secondary mirror hood is made of carbon fiber composite material, weighs 100g-300g, the secondary mirror hood is a three-layer cylindrical thin-wall structure, the thickness of each thin wall is 0.5mm-0.7mm, the minimum radial spacing of the three thin walls is 0.8mm, the three thin walls are respectively an outer aperture, a middle aperture and an inner aperture from the outside to the inside, the bottom surfaces of the outer aperture, the middle aperture and the inner aperture are connected by vertical ribs, a top surface mounting hole is set at the center of the inner aperture, and the top surface mounting hole is connected to the camera component.

[0007] Furthermore, the inner aperture diameter is 50 mm, the middle aperture height is 150 mm, and the outer aperture height is 200 mm.

[0008] Furthermore, the outer layer aperture and the middle layer aperture are provided with a plurality of connection grooves at equal intervals along the circumferential direction, and the connection grooves are connected to the camera components.

[0009] Furthermore, the diameter of the top surface mounting hole is 20 mm, threaded holes are arranged at equal intervals around the outside of the top surface mounting hole, carbon fiber gaskets are arranged on the upper and lower sides of the top surface mounting hole, the carbon fiber gasket is bonded to the top surface mounting hole by adhesive and fixed by threaded holes and screws, and the thickness of the carbon fiber gasket is 0.5 mm.

[0010] A forming mold for a secondary mirror sunshade made of carbon fiber composite material, comprising a mold shell and a core mold, wherein the core mold is arranged in the mold shell, the core mold comprises an outer core mold, an intermediate core mold and an inner core mold, the inner core mold is arranged inside the intermediate core mold, the outer core mold is arranged outside the intermediate core mold, the outer core mold comprises a plurality of identical arc-shaped valves, the intermediate core mold comprises a plurality of identical arc-shaped valves, the inner core mold is a truncated cone, a circle of grooves is arranged at the circular step of the inner core mold, a plurality of vertical protrusions are arranged at equal intervals on the side wall of the inner core mold, and the protrusions are connected to the sides of the valves of the outer core mold and the intermediate core mold.

[0011] Furthermore, the mold shell includes a base mold, an upper cover mold and an outer mold, the top surface of the outer mold (3) and the top surface of the core mold are connected to the upper cover mold, and the bottom surface of the outer mold and the bottom surface of the core mold are connected to the base mold.

[0012] Furthermore, the outer mold includes several identical arc-shaped valves and one end is set to be stepped, the upper cover mold is truncated cone-shaped, the stepped part of the outer mold is connected to the truncated cone-shaped step of the upper cover mold, and the bottom surface of the upper cover mold is connected to the top surface of the core mold.

[0013] Furthermore, the valves of the outer mold, the middle layer core mold and the outer layer core mold are provided with through holes at equal intervals along the vertical direction, and the upper surface of the base plate mold is provided with pin holes corresponding to the through holes of the outer mold, the middle layer core mold and the outer layer core mold.

[0014] Furthermore, the mold shell and the core mold are both made of 45 steel.

[0015] A method for forming a carbon fiber composite material secondary mirror sunshade is provided, which is processed by the forming mold of the carbon fiber composite material secondary mirror sunshade described above, and specifically comprises the following steps:

[0016] S1: evenly apply a release agent on the mold surface, and then lay prepreg on the surface of the core mold in the order of the inner core mold, the middle core mold and the outer core mold, so that the prepreg is completely attached to the molding mold;

[0017] S2: Connect and fix the mold shell to the core mold on which the prepreg is laid;

[0018] S3: Curing the mold with the prepreg, cooling it in a curing furnace after the curing is completed, and demoulding the mold in the order of the mold shell, the outer core mold, the middle core mold and the inner core mold after the molding mold is cooled;

[0019] S4: Grind the demoulding blank to make it smooth.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention selects a carbon fiber composite material sunshade with low deadweight and high stability, and uses an integrated molding technology to achieve high molding efficiency and strong structural reliability. The carbon fiber composite material sunshade has a good surface condition and uniform thickness, and the overall dimensions and mounting hole positions are reasonable.

[0022] 2. The sunshade of the present invention is provided with a three-layer cylindrical thin-wall structure, and the apertures are connected by vertical ribs. The structural layout is reasonable, and the multi-layer thin-wall structure makes full use of the satellite space, while providing an installation interface for the precision instruments of the space camera, and has a large bearing capacity, thereby improving the stability of the sunshade structure;

[0023] 3. The sunshade of the present invention adopts a molding process design, the mold combination form is simple, the operation difficulty is low, and the single-piece production cycle is short, which ensures effective control of the wall thickness of the structure and improves the demoulding efficiency;

[0024] 4. The present invention is applicable to the main support structure of a micro-space camera, and has the advantages of high lightness, high degree of integration, and convenient assembly and adjustment of camera parts. The present invention improves the molding quality and detection performance of the satellite space camera optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the axial structure of a carbon fiber composite material secondary mirror sunshade according to the present invention;

[0027] Figure 2 This is a schematic diagram of the front structure of a carbon fiber composite material secondary mirror sunshade according to the present invention;

[0028] Figure 3 It is a schematic cross-sectional structure diagram of a carbon fiber composite material secondary mirror sunshade according to the present invention;

[0029] Figure 4 This is an exploded view of a molding die for a carbon fiber composite material secondary mirror sunshade according to the present invention;

[0030] Figure 5 A schematic cross-sectional structure diagram of a molding die for a carbon fiber composite secondary mirror sunshade according to the present invention

[0031] Figure 6 The figure is a top view of a molding die for a secondary mirror sunshade made of carbon fiber composite material according to the present invention.

[0032] In the figure:

[0033] 1. Bottom plate mold; 2. Upper cover mold; 3. Outer mold; 4. Outer core mold; 5. Middle core mold; 6. Inner core mold; 7. Outer aperture; 8. Middle aperture; 9. Inner aperture; 10. Top surface mounting hole; 11-Connecting groove; 12. Protrusion. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0035] See also Figure 1The present embodiment describes a carbon fiber composite secondary mirror hood, wherein the secondary mirror hood is made of carbon fiber composite material and weighs 100g-300g. The hood is a three-layer cylindrical thin-walled structure, and the thickness of each thin wall layer is 0.5mm-0.7mm. The minimum radial spacing of the three thin walls is 0.8mm. The secondary mirror hood reduces the weight of the product while ensuring structural stability by using carbon fiber composite materials, and at the same time ensures the rationality of the structure of the secondary mirror hood. The three layers of thin walls are, from outside to inside, an outer aperture 7, a middle aperture 8, and an inner aperture 9, respectively. The bottom surfaces of the outer aperture 7, the middle aperture 8, and the inner aperture 9 are connected by vertical ribs. A top surface mounting hole 10 is arranged at the center of the inner aperture 9, and the top surface mounting hole 10 is connected to the camera component.

[0036] The secondary mirror hood made of composite material processed by the metal mold pressing technology and the hot-melt prepreg laying technology has a multi-layer thin-wall structure. The stability of the hood structure is improved by the multi-layer thin-wall structure, and the thickness of the multi-layer thin wall is uniform. In addition, by adopting carbon fiber composite materials, the hood meets the needs of low dead weight and high stability. The size of the hood is small, which is convenient for the installation and adjustment of camera parts.

[0037] The inner aperture 7 has a diameter of 50 mm, the middle aperture 8 has a height of 150 mm, and the outer aperture 7 has a height of 200 mm.

[0038] The outer aperture 7 and the middle aperture 9 are provided with a plurality of connection grooves 11 at equal intervals along the circumferential direction. The connection grooves 11 are connected to camera components. The connection grooves 11 are provided to ensure that the light shield is firmly connected to the camera components.

[0039] The diameter of the top surface mounting hole 10 is 20 mm, and a number of threaded holes are arranged at equal intervals around the outer side of the top surface mounting hole 10. Carbon fiber gaskets are arranged on the upper and lower sides of the top surface mounting hole 10. The carbon fiber gasket is bonded to the top surface mounting hole 10 by adhesive and fixed by threaded holes and screws. The thickness of the carbon fiber gasket is 0.5 mm. The carbon fiber gasket is an annular gasket. The circular hole of the carbon fiber gasket corresponds to the top surface mounting hole 10, so that the carbon fiber gasket can be reinforced with screws on the basis of bonding with adhesive. The strength of the sunshade and the added connection is increased by arranging the fiber gasket.

[0040] A forming mold for a secondary mirror sunshade made of carbon fiber composite material, comprising a mold shell and a core mold, wherein the core mold is arranged in the mold shell, the core mold comprising an outer core mold 4, an intermediate core mold 5 and an inner core mold 6, the inner core mold 6 is arranged inside the intermediate core mold 5, the outer core mold 4 is arranged outside the intermediate core mold 5, the outer core mold 4 comprises a plurality of identical arc-shaped valves, the intermediate core mold 5 comprises a plurality of identical arc-shaped valves, the inner core mold 6 is a truncated cone, a circle of grooves is arranged at the circular step of the inner core mold 6, a plurality of vertical protrusions 12 are arranged at equal intervals on the side wall of the inner core mold 6, and the protrusions 12 are connected to the sides of the valves of the outer core mold 4 and the intermediate core mold 5.

[0041] The molding mold is used for processing the secondary mirror sunshade of the carbon fiber composite material. The prepreg is laid between each layer of the mold and then the secondary mirror sunshade of the carbon fiber composite material is processed through heating, curing and demoulding.

[0042] The mold shell includes a base mold 1, an upper cover mold 2 and an outer mold 3, the top surface of the outer mold 3 and the top surface of the core mold are connected to the upper cover mold 2, and the bottom surface of the outer mold 3 and the bottom surface of the core mold are connected to the base mold 1.

[0043] The outer mold 3 includes several identical arc-shaped valves and one end is set to be stepped. The upper cover mold 2 is truncated cone-shaped. The stepped part of the outer mold 3 is connected to the truncated cone-shaped step of the upper cover mold 2. The bottom surface of the upper cover mold 2 is connected to the top surface of the core mold. The design of the stepped structure ensures the stability of the mold connection during the processing.

[0044] The valves of the outer mold 3, the middle layer core mold 5 and the outer layer core mold 4 are provided with through holes at equal intervals in the vertical direction, and the upper surface of the base plate mold 1 is provided with pin holes corresponding to the through holes of the outer mold 3, the middle layer core mold 5 and the outer layer core mold 4. The outer mold 3, the middle layer core mold 5 and the outer layer core mold 4 are fixedly connected with the pin holes preset on the upper surface of the base plate mold 1 by inserting long bolts into the through holes.

[0045] The mold shell and the core mold are both made of 45# steel.

[0046] A method for forming a carbon fiber composite material secondary mirror sunshade is provided, which is processed by the forming mold of the carbon fiber composite material secondary mirror sunshade described above, and specifically comprises the following steps:

[0047] S1: subjecting the above-set composite secondary mirror sunshade forming mold to high-temperature degreasing treatment, then grinding the surface with 100-mesh sandpaper, and then cleaning the iron filings on the mold surface with cotton gauze soaked in acetone, and finally evenly coating the mold surface with a release agent, and then laying prepreg on the core mold surface in the order of the inner core mold 6, the middle core mold 5 and the outer core mold 4, using a specific laying angle of 0°, 90°, 45°, -45° and laying in a certain order, so that the prepreg is completely fitted with the forming mold, and at the same time, the bubbles between the prepreg layers are driven out;

[0048] S2: After the prepreg on the core mold is laid, the mold shell is connected and fixed to the core mold with the prepreg laid, and the core mold and the outer mold 3 are fixed to the bottom plate mold 1 through long bolts and pin holes on the upper surface of the bottom plate mold 1, and finally the upper cover mold 2 is placed on the core mold and connected to the outer mold 3;

[0049] S3: Curing the mold with the prepreg according to the curing system of epoxy resin, that is, keeping it at 100°C for two hours, then heating it to 150°C and keeping it for another two hours. After the curing is completed, the mold should be placed in a curing furnace to cool. After the molding mold is cooled, the mold temperature is usually reduced to no more than 30°C from room temperature, and then demoulding is performed in the order of mold shell, outer core mold 4, middle core mold 5 and inner core mold 6. The demoulding order should be opposite to the order of mold assembly.

[0050] S4: The demoulded blank is polished and flattened with a file, and then through holes corresponding to the circular holes of the carbon fiber gasket are opened around the outer side of the top surface mounting hole 10. The carbon fiber gasket with a thickness of 0.5 mm is polished with 50-grit sandpaper and bonded to the upper and lower sides of the top surface mounting hole 10. Then, the connection between the top surface mounting hole 10 and the carbon fiber gasket is reinforced with screws. The adhesive used for bonding is room temperature curing adhesive. Finally, the carbon fiber composite material secondary mirror hood is subjected to sinusoidal vibration test and random vibration test.

[0051] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A carbon fiber composite secondary mirror sunshade, characterized in that: The secondary mirror hood is made of carbon fiber composite material and weighs 100g-300g. The secondary mirror hood is a three-layer cylindrical thin-wall structure, each layer of thin wall has a thickness of 0.5mm-0.7mm, and the minimum radial spacing of the three layers of thin walls is 0.8mm. The three layers of thin walls are respectively an outer layer aperture (7), an intermediate layer aperture (8) and an inner layer aperture (9) from the outside to the inside. The bottom surfaces of the outer layer aperture (7), the intermediate layer aperture (8) and the inner layer aperture (9) are connected by vertical ribs. A top surface mounting hole (10) is arranged at the center of the inner layer aperture (9), and the top surface mounting hole (10) is connected to a camera component.

2. The carbon fiber composite secondary mirror sunshade according to claim 1, characterized in that: The inner layer aperture (7) has a diameter of 50 mm, the middle layer aperture (8) has a height of 150 mm, and the outer layer aperture (7) has a height of 200 mm.

3. The carbon fiber composite secondary mirror sunshade according to claim 1, characterized in that: The outer layer aperture (7) and the middle layer aperture (9) are provided with a plurality of connection grooves (11) at equal intervals along the circumferential direction, and the connection grooves (11) are connected to camera components.

4. The carbon fiber composite material secondary mirror sunshade according to claim 1, characterized in that: The top surface mounting hole (10) has a diameter of 20 mm, threaded holes are arranged at equal intervals around the outside of the top surface mounting hole (10), carbon fiber gaskets are arranged on the upper and lower sides of the top surface mounting hole (10), the carbon fiber gasket is bonded to the top surface mounting hole (10) by adhesive and fixed by threaded holes and screws, and the thickness of the carbon fiber gasket is 0.5 mm.

5. A molding die for the carbon fiber composite material secondary mirror sunshade according to claim 1, characterized in that: The invention comprises a mold shell and a core mold, wherein the core mold is arranged in the mold shell, and the core mold comprises an outer core mold (4), an intermediate core mold (5) and an inner core mold (6), the inner core mold (6) is arranged inside the intermediate core mold (5), the outer core mold (4) is arranged outside the intermediate core mold (5), the outer core mold (4) comprises a plurality of identical arc-shaped valves, the intermediate core mold (5) comprises a plurality of identical arc-shaped valves, the inner core mold (6) is a truncated cone, a circle of grooves is arranged at the circular step of the inner core mold (6), and a plurality of vertical protrusions (12) are arranged at equal intervals on the side wall of the inner core mold (6), and the protrusions (12) are connected to the side edges of the valves of the outer core mold (4) and the intermediate core mold (5).

6. The molding die of the carbon fiber composite material secondary mirror sunshade according to claim 5, characterized in that: The mold shell comprises a base plate mold (1), an upper cover mold (2) and an outer mold (3); the top surface of the outer mold (3) and the top surface of the core mold are connected to the upper cover mold (2); the bottom surface of the outer mold (3) and the bottom surface of the core mold are connected to the base plate mold (1).

7. The molding die of the carbon fiber composite material secondary mirror sunshade according to claim 6, characterized in that: The outer mold (3) comprises a plurality of identical arc-shaped valves and one end is arranged in a stepped shape. The upper cover mold (2) is in a truncated cone shape. The stepped portion of the outer mold (3) is connected to the truncated cone-shaped stepped portion of the upper cover mold (2). The bottom surface of the upper cover mold (2) is connected to the top surface of the core mold.

8. The molding die of the carbon fiber composite material secondary mirror sunshade according to claim 7, characterized in that: The valves of the outer mold (3), the middle layer core mold (5) and the outer layer core mold (4) are provided with through holes at equal intervals in the vertical direction, and the upper surface of the base plate mold (1) is provided with pin holes corresponding to the through holes of the outer mold (3), the middle layer core mold (5) and the outer layer core mold (4).

9. The molding die of the carbon fiber composite material secondary mirror sunshade according to claim 5, characterized in that: The mold shell and the core mold are both made of 45# steel.

10. A method for forming a secondary mirror sunshade made of carbon fiber composite material, characterized in that: The molding die of the carbon fiber composite material secondary mirror sunshade according to any one of claims 5 to 9 specifically comprises the following steps: S1: evenly apply a release agent on the mold surface, and then lay prepreg on the surface of the core mold in the order of the inner core mold (6), the middle core mold (5) and the outer core mold (4), so that the prepreg is completely attached to the molding mold; S2: Connect and fix the mold shell to the core mold on which the prepreg is laid; S3: Curing the mold with the prepreg, cooling it in a curing furnace after the curing is completed, and demoulding the mold in the order of the mold shell, the outer core mold (4), the middle core mold (5) and the inner core mold (6) after the molding mold is cooled; S4: Grind the demoulding blank to make it smooth.

Images