A stacked cryogenic light engine assembly support structure

Abstract

The application discloses a laminated low-temperature optical machine assembly support structure, which comprises three groups of identical laminated structures, and the low-temperature optical machine assembly is supported through the three groups of identical laminated structures. Each group of laminated structures comprises a mandrel, a plurality of metal laminations, a plurality of non-metal laminations, a nested pressing sheet and a pressing screw. The plurality of metal laminations and the plurality of non-metal laminations are staggered on the center column of the mandrel to form a laminated structure. The nested pressing sheet is installed on the laminated structure, and the mandrel, the laminated structure and the nested pressing sheet are connected into an integral whole through the pressing screw. The laminated low-temperature optical machine assembly support structure can consider the performance of rigidity, thermal resistance and damping, and can make the low-temperature optical machine assembly meet the imaging requirement, the thermal control requirement and the mechanical environment adaptation requirement.

Description

Technical Field

[0001] This invention belongs to the field of optomechanical structure design technology, and particularly relates to a stacked low-temperature optomechanical component support structure. Background Technology

[0002] According to the Stefan-Boltzmann law, the radiant flux density of an object is proportional to the fourth power of its absolute temperature. Therefore, in mid- and long-wave infrared optical systems, the background noise of the optomechanical system is often reduced by lowering the temperature of the optomechanical components, thereby improving the detection sensitivity of the optical system.

[0003] As part of a cryogenic optical system, the supporting structure of cryogenic optomechanical components typically needs to meet three requirements: first, the stiffness performance must meet the imaging requirements of the optical system; second, the thermal resistance performance must meet the thermal control requirements of the cryogenic optomechanical components; and third, the damping performance must adapt to the mechanical environmental conditions.

[0004] Currently, there are three main types of support methods for cryogenic optomechanical components: one is to use a flexible structure for quasi-statically determinate support; the second is to achieve positioning and unloading through kinematics; and the third is to use a single insulating material for ultra-statically determinate support. Qiu Shanchang et al., in their paper "Research on Support Structure of Cryogenic Infrared Optical Lens," used a cantilever flexible structure to achieve quasi-statically determinate support for the lens. This support structure can meet the thermal unloading and thermal isolation requirements of cryogenic optomechanical components, but its load-bearing capacity is weak and its damping characteristics are poor, making it unsuitable for applications with large masses and harsh mechanical environments. Zhou Chao, in his paper "Design of Optomechanical Structure for Cryogenic Infrared Systems," used a 45° inclined plane in conjunction with the lens mount to achieve kinematic support for the lens. This support method can meet the thermal unloading requirements and has high stiffness, but its ability to unload assembly stress is poor and its thermal isolation performance is weak, making it unsuitable for stress-sensitive applications and applications with high thermal control requirements. In their paper "Design and Simulation Analysis of Vacuum Cryogenic Insulation Support", Han Ruixiong et al. used glass fiber material to make a thin-walled structure and four layers of precision-machined disks with interference fit to achieve static determinate support for cryogenic components. This support method can meet the strength requirements and thermal isolation requirements of cryogenic components, but its load capacity is weak and its stress unloading capacity is poor, making it unsuitable for applications with large mass and stress sensitivity.

[0005] It is evident that existing cryogenic support structures cannot simultaneously achieve performance in terms of stiffness, thermal resistance, and damping, and thus cannot enable cryogenic optomechanical components to meet imaging requirements, thermal control requirements, and mechanical environment adaptation requirements at the same time. Summary of the Invention

[0006] The technical problem solved by the present invention is to overcome the shortcomings of the prior art and provide a stacked low-temperature optomechanical component support structure. This structure can take into account the performance of stiffness, thermal resistance and damping, so that the low-temperature optomechanical component can simultaneously meet the imaging requirements, thermal control requirements and mechanical environment adaptation requirements.

[0007] To address the aforementioned technical problems, this invention discloses a stacked low-temperature optical engine component support structure, comprising: three identical stacked structures; the three identical stacked structures are used to support the low-temperature optical engine component.

[0008] A single-unit stacked structure includes: a mandrel, several metal stacks, several non-metal stacks, nested pressure plates, and clamping screws;

[0009] Several metal laminations and several non-metal laminations are interlaced on the central column of the mandrel to form a layered structure;

[0010] Nested pressure plates are installed on the laminated structure, and the mandrel, laminated structure and nested pressure plates are connected into a whole by clamping screws.

[0011] In the above-mentioned stacked low-temperature optical engine component support structure, each metal lamination and each non-metal lamination has 6 waist-shaped slots of the same size; among them, the centers of the 12 semicircles of the 6 waist-shaped slots are distributed at equal intervals at a 30° angle.

[0012] In the aforementioned stacked low-temperature optical engine component support structure, the waist-shaped grooves of the metal laminations and the waist-shaped grooves of the non-metal laminations are offset by 30° relative to each other in the axial direction.

[0013] In the above-mentioned stacked low-temperature optomechanical component support structure, the staggered arrangement of several metal laminations and several non-metal laminations on the central column of the mandrel means: ...metal lamination / non-metal lamination / metal lamination / non-metal lamination...and so on, cyclically arranged on the central column of the mandrel.

[0014] In the above-mentioned stacked low-temperature optomechanical component support structure, the bottom and top layers of the stacked structure are both non-metallic laminates.

[0015] In the aforementioned layered low-temperature optomechanical component support structure

[0016] The metal lamination material is a titanium alloy;

[0017] The non-metallic laminates, nested clamping plates, and clamping screws are made of polyimide.

[0018] In the aforementioned stacked low-temperature optomechanical component support structure, the stiffness, thermal resistance, and damping of the support structure are optimized by adjusting the dimensions of the metal and non-metal laminations, the roughness of the contact surfaces, the total number of layers, and the installation clamping force.

[0019] In the aforementioned stacked low-temperature optical engine component support structure, the dimensions of the metal laminations and non-metal laminations are adjusted, including: adjusting the outer diameter, thickness, and waist-shaped groove dimensions of the metal laminations and non-metal laminations.

[0020] In the aforementioned stacked low-temperature optomechanical component support structure, adjusting the roughness of the contact surface refers to changing the roughness of the non-metallic contact surface according to requirements.

[0021] In the aforementioned stacked low-temperature optomechanical component support structure, adjusting the installation clamping force refers to adjusting the installation clamping force borne by the stacked structure by adjusting the tightening torque of the connecting screws when connecting the stacked structure to the optomechanical component.

[0022] The present invention has the following advantages:

[0023] This invention discloses a stacked low-temperature optomechanical component support structure that can balance stiffness, thermal resistance, and damping performance. It features high stiffness, strong unloading capacity, high thermal resistance, and excellent damping performance, enabling the optomechanical component to simultaneously meet imaging requirements, thermal control requirements, and mechanical environment adaptability requirements. It is suitable for supporting low-temperature optomechanical components with large mass, large cooling capacity, and harsh mechanical environment conditions. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a single-unit stacked structure in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of a mandrel in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of a metal stack in an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of a non-metallic laminate structure in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of a nested tablet structure in an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of a clamping screw in an embodiment of the present invention;

[0030] Figure 7 This is an assembly diagram of a single-unit stacked structure in an embodiment of the present invention;

[0031] Figure 8 This is an assembly cross-sectional view of a single-unit stacked structure in an embodiment of the present invention;

[0032] Figure 9 This is an assembly cross-sectional view of another single-unit stacked structure in an embodiment of the present invention;

[0033] Figure 10 This is a schematic diagram of a three-layered structure supporting a low-temperature lens group in an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0035] like Figures 1-6 In this embodiment, the stacked low-temperature optical engine component support structure includes three identical stacked structures; the low-temperature optical engine component is supported by these three identical stacked structures. Each stacked structure may specifically include: a mandrel 1, several metal laminations 2, several non-metal laminations 3, a nested pressure plate 4, and a clamping screw 5. Further, the several metal laminations 2 and several non-metal laminations 3 are alternately threaded onto the central column of the mandrel 1 to form a stacked structure; the nested pressure plate 4 is installed on the stacked structure, and the mandrel 1, the stacked structure, and the nested pressure plate 4 are connected as a whole by the clamping screw 5.

[0036] In this embodiment, as Figure 2 As shown, the mandrel 1 includes a center column and a flange. The center column is a hollow structure; the flange has three threaded holes and three process through holes with countersunk holes for assembly of the stacked structure.

[0037] In this embodiment, as Figure 3 and Figure 4 Each metal lamination 2 and each non-metal lamination 3 has six identical waist-shaped grooves and three process through holes. Both the waist-shaped grooves and process through holes are evenly distributed circumferentially. The waist-shaped grooves are mainly used to reduce the nominal contact area of ​​the laminations, while the process through holes are mainly used to achieve the assembly of the stacked structure. The centers of the twelve semicircles of the six waist-shaped grooves are evenly spaced at 30° angles. Furthermore, when several metal laminations 2 and several non-metal laminations 3 are alternately threaded onto the central post of the mandrel 1, the waist-shaped grooves of the metal laminations 2 and the non-metal laminations 3 are offset relative to each other by 30° in the axial direction.

[0038] In this embodiment, as Figure 5 The nested tablet 4 has three through holes with countersunk holes and three process through holes, both of which are evenly distributed circumferentially and are 45° apart in the direction of the axis.

[0039] In this embodiment, as Figure 6 The end of the clamping screw 5 is machined with an external thread, the thread length of which is 1mm longer than the thickness of the mandrel 1 flange. A threaded hole is drilled on the flange of mandrel 1, and the clamping screw 5 is connected to the flange of mandrel 1 by the thread. Adhesive is applied to the threaded section to prevent loosening.

[0040] In this embodiment, the aforementioned "a plurality of metal laminations 2 and a plurality of non-metal laminations 3 are alternately threaded on the central post of the mandrel 1" means: ...metal lamination 1 / non-metal lamination 2 / metal lamination 1 / non-metal lamination 2... are cyclically threaded on the central post of the mandrel 1. Furthermore, when the laminations are alternately threaded on the central post of the mandrel 1, it generally begins with a non-metal lamination and ends with a non-metal lamination; that is, the bottom and top layers of the laminated structure are both non-metal laminations 3.

[0041] In this embodiment, the metal lamination 2 is made of titanium alloy and can be machined from titanium alloy rods. The non-metallic lamination 3, the nested pressure plate 4, and the clamping screw 5 are made of polyimide and can be machined from polyimide rods.

[0042] In this embodiment, the stiffness, thermal resistance, and damping of the supporting structure can be optimized by adjusting the dimensions, contact surface roughness, total number of layers, and installation clamping force of the metal lamination 2 and the non-metal lamination 3. Specifically, adjusting the dimensions of the metal lamination 2 and the non-metal lamination 3 can include adjusting the outer diameter, thickness, and size of the oblong groove of the metal lamination 2 and the non-metal lamination 3. Adjusting the contact surface roughness means changing the roughness of the non-metallic contact surface as needed; generally, the roughness Ra of the metal lamination 2 is better than 1.6, and the roughness of the non-metal lamination 3 is controlled as needed through machining processes, resulting in a larger surface roughness than the metal lamination 2. Adjusting the installation clamping force means adjusting the installation clamping force borne by the stacked structure by adjusting the tightening torque of the connecting screws when connecting the stacked structure to the optomechanical component.

[0043] In this embodiment, when several metal laminations 2 and several non-metal laminations 3 are alternately threaded onto the central post of the mandrel 1, the gaps between the parts need to be controlled to reduce heat leakage from contact. Preferably, the gaps between the metal laminations 2 and non-metal laminations 3 and the central post of the mandrel 1 are generally controlled to be 0.3mm to 0.5mm; the gaps between the nested pressure plates 4 and the central post of the mandrel 1 are generally controlled to be 0.1mm to 0.2mm; the gaps between the central post of the mandrel 1 and the mounting surface of the support structure are generally controlled to be 0.3mm to 0.5mm; and the gaps between the head of the clamping screw 5 and the mounting surface of the support structure are generally controlled to be 0.3mm to 0.5mm.

[0044] In this embodiment, the following key dimensions can also be controlled: the inner diameter of the metal lamination 1 and the non-metal lamination 2 is 0.3mm to 0.5mm larger than the outer diameter of the central column of the mandrel 1; the inner diameter of the nested pressure plate 4 is 0.1mm to 0.2mm larger than the outer diameter of the central column of the mandrel 1; the sum of the thickness of the laminated structure formed by the metal lamination 2 and the non-metal lamination 3 and the thickness of the nested pressure plate 4 is 0.3mm to 0.5mm larger than the height of the central column of the mandrel 1; the countersunk groove of the clamping screw on the nested pressure plate 4 is 0.3mm to 0.5mm larger than the screw head thickness of the clamping screw 5; the sum of the remaining thicknesses of the flange of the mandrel 1, the metal lamination 2, the non-metal lamination 3, and the nested pressure plate 4 after the countersunk groove is cut is 0.1mm to 0.2mm larger than the length of the stud section of the clamping screw 5.

[0045] In this embodiment, as Figures 7-9 When assembling the stacked structure, guide rod 6 is selected as the assembly tool. During assembly, guide rod 6 is first installed on the flange of mandrel 1. Then, metal lamination 2, non-metal lamination 3, and nested pressure plate 4 are threaded onto the central column of mandrel 1 through guide rod 6. J-133 glue is then applied to the threaded section of clamping screw 5. The mandrel 1, metal lamination 2, non-metal lamination 3, and nested pressure plate 4 are connected into a whole by clamping screw 5. The tightening torque is controlled at 0.1 N·m to 0.2 N·m. Finally, guide rod 6 is pulled out of the structure, thus completing the assembly of a single stacked structure.

[0046] Based on the above embodiments, the following description will illustrate a specific application scenario of the stacked low-temperature optomechanical component support structure.

[0047] like Figure 10 Three identical stacked structures were used as the support structure for the stacked cryogenic optomechanical assembly to support the cryogenic lens group. Before support, the screw specifications required for connecting the stacked cryogenic optomechanical assembly support structure and the cryogenic lens group were determined through strength verification. Screws one size larger than the verification result were selected for connection. The installation clamping force of each stacked structure was adjusted by changing the screw tightening torque to ensure that the ratio of the actual applied screw tightening torque to the standard tightening torque corresponding to the screw specification determined by verification was greater than the ratio of their diameters.

[0048] In this application scenario, the cryogenic lens assembly weighs 12kg, is assembled at room temperature and operates at low temperature, and is fixed to the lens holder via a stacked cryogenic optomechanical component support structure. During operation, the cryogenic lens assembly's own temperature range is 200±2K, and the lens holder's temperature range is 291±2K. The cryogenic lens assembly is required to have a fundamental frequency greater than 120Hz, an acceleration magnification of less than 15 times at the 0.5g sweep frequency resonance point at the lens position, and image quality and temperature control requirements during cryogenic operation.

[0049] During the implementation of the case, thermal analysis of the entire machine determined that the thermal resistance of a single-unit laminated structure must be greater than 450 K / W. Using this thermal resistance value as a constraint, and combining it with the thermal resistance calculation formula, some parameters of the single-unit laminated structure were determined: the total number of layers is 21, and the outer diameters of the metal laminate 2 and the non-metal laminate 3 are... The thicknesses are 1.4 mm and 0.9 mm respectively, and the area of ​​the waist-shaped groove is 13.6 mm². 2 Strength analysis determined that M6 screws were needed to connect the single-unit stacked structure to the cryogenic lens group. However, M8 screws were used in practice, with a tightening torque 1.8 times the nominal tightening torque of the M6 ​​screw. The surface roughness Ra of the metal stack 2 was controlled at 1.6 μm, and the surface roughness Ra of the non-metal stack 3 was controlled at 3.2 μm. Other key dimensional controls for the parts are as follows: the inner diameter of the metal lamination 2 and the non-metal lamination 3 is 0.3 mm larger than the outer diameter of the central column of the mandrel 1; the inner diameter of the nested pressure plate 4 is 0.1 mm larger than the outer diameter of the central column of the mandrel 1; the sum of the thicknesses of the metal lamination 2, the non-metal lamination 3, and the nested pressure plate 4 is 0.3 mm larger than the height of the central column of the mandrel 1; the countersunk groove of the clamping screw on the nested pressure plate 4 is 0.3 mm larger than the screw head thickness of the clamping screw 5; the sum of the remaining thicknesses of the mandrel 1 flange, the metal lamination 2, the non-metal lamination 3, and the nested pressure plate 4 after the countersunk grooves are cut is 0.1 mm larger than the length of the stud section of the clamping screw 5. Thermal and vibration tests were conducted on the low-temperature lens assembly with its support structure. The test results show that the image quality and temperature of the low-temperature lens assembly meet the requirements, the fundamental frequency is 115 Hz, and the magnification of the 0.5g sweep frequency resonance acceleration at the lens position is 16.2 times. The fundamental frequency and acceleration amplification factor do not meet the requirements. It is necessary to increase the bending stiffness and damping of the supporting structure while ensuring that the thermal resistance and thermal unloading capacity do not change significantly.

[0050] During the implementation of the case, adjustments were made to the single-unit stacked structure based on the experimental results: the total number of stacks was adjusted to 31, and the outer diameters of the metal laminate 2 and the non-metal laminate 3 were adjusted to... The thicknesses were adjusted to 1.1mm and 0.6mm respectively, and the area of ​​the waist-shaped groove was adjusted to 23.5mm². 2 The tightening torque was adjusted to 1.6 times the nominal tightening torque of the M6 ​​screw, and the roughness of the non-metallic lamination 3 was adjusted to 6.3μm. After the adjustment, the low-temperature lens group with support structure was subjected to thermal and vibration tests again. The image quality and temperature did not change significantly, the fundamental frequency was increased to 126Hz, and the acceleration amplification factor at the 0.5g sweep frequency resonance point of the lens position was reduced to 13.3 times. All performance requirements were met.

[0051] In summary, the stacked low-temperature optomechanical component support structure disclosed in this invention has at least the following characteristics:

[0052] High stiffness: The stacked structure is a structure made of thin sheets. A single stacked structure has a large moment of inertia in the plane perpendicular to the axis, thus having a large bending stiffness. The optomechanical component supported by three stacked structures has strong anti-overturning ability and high stiffness.

[0053] Strong assembly stress unloading capacity: The single-unit stacked structure is composed of two thin sheets with significantly different elastic moduli, stacked alternately. The contact stiffness of a large number of micro-contact points on a single pair of contact interfaces is connected in parallel, while the contact stiffness of multiple pairs of contact interfaces is connected in series. The series and parallel connection of multi-level stiffness enables the support structure proposed in this invention to fully adapt to the shape and position of the load mating surface, and has a strong ability to unload assembly stress.

[0054] Strong thermal stress unloading capacity: The modulus and hardness of polyimide are much lower than those of titanium alloy. The tangential contact stiffness of the interface between the metal and non-metal laminates decreases significantly with decreasing compressive stress. At room temperature and pressure, the laminated support structure is compressed by screws; as the temperature decreases, the shrinkage of polyimide is greater than that of the titanium alloy screws, the screw clamping force decreases, and the stiffness of the support structure perpendicular to the axial direction is much smaller than its axial stiffness. Therefore, the support structure proposed in this invention has a strong unloading capacity for low-temperature thermal stress perpendicular to its axial direction.

[0055] High thermal resistance: The support structure uses titanium alloy and polyimide materials with low thermal conductivity, reducing heat leakage from the material selection stage; both the metal and non-metal laminations have waist-shaped grooves and are stacked at a 30° offset around the axis, reducing the contact area while increasing the heat transfer path; the central column of the mandrel is designed with a thin-walled structure, reducing the heat transfer area; gaps are designed between the metal laminations, non-metal laminations, nested pressing plates, and the central column of the mandrel to avoid contact heat leakage; the metal and non-metal laminations are staggered to form a layered structure, which greatly increases the contact thermal resistance. The combined effect of these measures gives the support structure proposed in this invention the characteristic of high thermal resistance.

[0056] Excellent damping performance: The polyimide material itself has a large damping loss factor. At the same time, the contact interface of the laminated structure brings large contact damping. These measures enable the support structure proposed in this invention to have excellent damping performance.

[0057] Taking into account the performance of stiffness, thermal resistance and damping: The stiffness, thermal resistance and damping performance of the support structure are related to the size of the metal laminations and non-metal laminations, the roughness of the contact surface, the total number of layers and the installation clamping force. By adjusting these parameters in combination with simulation analysis or test results, the optimal matching of the stiffness, thermal resistance and damping performance of the support structure proposed in this invention can be achieved.

[0058] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0059] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A stacked low-temperature optomechanical component support structure, characterized in that, include: Three identical stacked structures; The low-temperature optical engine components are supported by three identical stacked structures; A single-unit stacked structure includes: a mandrel (1), several metal laminations (2), several non-metal laminations (3), nested pressure plates (4), and clamping screws (5); wherein, several metal laminations (2) and several non-metal laminations (3) are alternately threaded on the central column of the mandrel (1) to form a stacked structure; nested pressure plates (4) are installed on the stacked structure, and the mandrel (1), the stacked structure, and the nested pressure plates (4) are connected into a whole by clamping screws (5); the bottom layer and the top layer of the stacked structure are both non-metal laminations (3). Each metal lamination (2) and each non-metal lamination (3) has 6 waist-shaped grooves of the same size; the centers of the 12 semicircles of the 6 waist-shaped grooves are distributed at equal intervals at an angle of 30°; the waist-shaped grooves of the metal lamination (2) and the waist-shaped grooves of the non-metal lamination (3) are offset relative to each other by 30° in the direction around the axis. The metal laminations (2) are made of titanium alloy; the non-metal laminations (3), nested pressure plates (4) and clamping screws (5) are made of polyimide. The central column of the mandrel (1) is designed as a thin-walled structure.

2. The layered low-temperature optomechanical component support structure according to claim 1, characterized in that, The alternating threading of several metal laminations (2) and several non-metal laminations (3) on the central post of the mandrel (1) means that the metal laminations (2) / non-metal laminations (3) / metal laminations (2) / non-metal laminations (3) are threaded in a cyclic manner on the central post of the mandrel (1).

3. The layered low-temperature optomechanical component support structure according to claim 1, characterized in that, By adjusting the dimensions, surface roughness, total number of layers, and installation clamping force of the metal laminations (2) and non-metal laminations (3), the stiffness, thermal resistance, and damping of the support structure can be optimized and matched.

4. The stacked low-temperature optomechanical component support structure according to claim 3, characterized in that, Adjusting the dimensions of the metal lamination (2) and the non-metal lamination (3) includes adjusting the outer diameter, thickness, and waist-shaped groove of the metal lamination (2) and the non-metal lamination (3).

5. The stacked low-temperature optomechanical component support structure according to claim 3, characterized in that, Adjusting the surface roughness of the contact surface means changing the roughness of the non-metallic contact surface according to requirements.

6. The stacked low-temperature optomechanical component support structure according to claim 3, characterized in that, Adjusting the installation clamping force refers to adjusting the installation clamping force borne by the stacked structure by adjusting the tightening torque of the connecting screws when connecting the stacked structure to the optomechanical components.

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