CN212933116U

CN212933116U - Support assembly for space large-aperture reflector

Info

Publication number: CN212933116U
Application number: CN202021257429.6U
Authority: CN
Inventors: 刘晓华; 姚劲刚; 郑庚
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2019-11-18
Filing date: 2020-07-01
Publication date: 2021-04-09
Anticipated expiration: 2030-07-01
Also published as: CN110780416A; CN111694128A

Abstract

The patent discloses a supporting component for a space heavy-calibre speculum. The supporting component consists of a reflector supporting back plate, a reflector supporting cylinder, a locking nut and a flexible gasket. The axial positioning of the reflector is fixed on the reflector supporting back plate through a locking nut and a front end screw column of the reflector supporting cylinder, and the locking nut and the reflector are isolated by a flexible gasket and used for uniformly applying locking pressure. The advantage of this patent lies in: the reflector support assembly solves the problems of complex design and higher assembly process requirement of a reflector support structure in the original large-caliber off-axis three-mirror optical system and the like; meanwhile, the problem of additional stress on the reflector body caused by cantilever support, temperature field change and installation and detection modes of the traditional large-caliber support structure is solved. The influence of the support on the optical surface type can be effectively reduced. This patent is owing to simple structure, easily realization, has actual engineering meaning to the lightweight of space heavy-calibre optical load.

Description

Support assembly for space large-aperture reflector

Technical Field

This patent belongs to the space flight field, relates to one kind and is used for space heavy-calibre speculum supporting component, specifically is the unstressed support problem of heavy-calibre speculum in order to solve among the space flight field. The design can effectively simplify the design difficulty of the large-caliber reflector support and the difficulty of engineering realization; the assembly and calibration efficiency of the large-aperture reflector can be effectively improved; the influence of the assembly stress of the large-caliber reflector on the surface type can be effectively reduced. Has great practical engineering application value and economic benefit.

Background

With the continuous development of aerospace industry in China, the ground resolution requirement of a space optical remote sensing instrument is higher and higher; meanwhile, the requirements on detection field (width) and detection sensitivity are higher and higher; the three-mirror optical system becomes a trend for solving the current problems, and the development of a decimeter-level visible light and a meter-level infrared remote sensing instrument is started at present. With the improvement of ground resolution, the demand on optical caliber is more and more increased, the caliber is developed from the original 200mm caliber to the caliber of 1m, and a reflector with the caliber of more than 2m is developed at present; meanwhile, the improvement of the optical image quality has higher and higher requirements on the surface type of the optical component.

The reflector is a key component of a reflective optical system, and the reflector supporting technology is one of the most key technologies in the engineering application of the large-aperture reflector. As the aperture of the mirror increases, it is necessary to design the mirror to be light in weight so as to reduce the influence of the self-weight distortion. After the main mirror is reduced in weight, the sensitivity of the mirror to supporting stress is rapidly increased because the specific stiffness is improved as the weight reduction ratio is increased, but the absolute stiffness of the structure is decreased. Meanwhile, the change of the space environment temperature easily causes the surface shape change of the reflector through the supporting structure. After entering the space orbit, the mirror surface shape of the main mirror which meets the engineering use requirement on the ground is easy to change due to the disappearance of the dead weight and the complicated change of the external temperature, deviates from the requirements of design and processing, and directly influences the imaging effect of the space camera.

The design requirements of the support system are different according to different working conditions, materials, processing conditions, use conditions and the like of the primary mirror. In a space optical system, the support design of the primary mirror mainly considers the influence of gravity, temperature and impact vibration. Thus, the loads on the support system are gravitational, thermodynamic and kinetic loads.

The support of the primary mirror is to effectively position the primary mirror and unload the dead weight of the primary mirror, so as to reduce the deformation of the dead weight and bear the influence of temperature and impact. The existing supporting schemes are that position limitation and force action are applied to the main mirror at certain positions of the main mirror through a mechanical structure, supporting force and mirror body gravity are balanced, and the influence of gravity on mirror surface deformation can be partially eliminated. For the large-aperture primary mirror, the following support systems are used.

1) Center support

For the reflector with the middle and small caliber, the central shaft can be used for realizing positioning and constraint independently; for the reflector with a larger aperture, the mirror surface deformation is larger when the reflector is used alone, and the predetermined supporting effect can be met only by matching with other supporting modes. At this time, the central shaft only plays a role of positioning and restraining, and has small load.

2) Multi-point support system

Typical multi-point support systems include Grubb systems, Hinddle systems, Lassell systems, and pneumatic (hydraulic) support systems.

(1) Grubb braced system

This system uses a hinge bracket structure that uses the mutual balancing of the own weights of the mirror parts. The structure is equivalent to a lever mechanism, and the extending part of the lever and the corresponding mirror body supporting part are balanced by virtue of space, and the rigidity of the supporting member does not influence the supporting effect.

(2) Hinddle support system

The system applies a lever mechanism to the Grubb system, which is equivalent to connecting two Grubb systems with a balance lever, and one degree of freedom is increased. The number of the supporting points is expanded, and the problem of over-constraint cannot occur.

(3) Lassell supporting system

The Lassell supporting system is essentially a lever structure, and the gravity of the balancing weight is changed into supporting force for the mirror body through the lever. The supporting points and the distribution of the system are not affected mutually, and the deformation of the local area can be changed by adjusting a single supporting point according to the requirement. Are commonly used as side supports.

(4) Air or hydraulic support system

The system adopts air pressure or hydraulic pressure to replace mechanical acting force, generates surface acting force on the surface of the air (liquid) bag, realizes the restraint and the positioning of the mirror body, and can correct the local deformation of the mirror surface to a certain degree.

(5) Edge support

The edge support of the large-aperture reflector has heavy weight, and the temperature influence is difficult to eliminate.

The back multi-point support is a main way for solving the problem of supporting a large-aperture reflector of an off-axis reflective optical system at present, and designers in the field develop a large amount of work in the aspects of cementing transition sleeves, decoupling design with fixed degree of freedom and the like and obtain remarkable achievement. But the difficulty in the aspects of the processing technology of the reflector support hole, the assembly technology of the support structure and the like is greatly increased. Meanwhile, the machining precision, the assembling process and the steps of the parts directly influence the final assembling quality of the reflector.

The method is used for eliminating the influence of external heat flow change generated by satellite orbit change on the temperature level of a reflector of a remote sensing instrument, so that temperature stress causes the shape of the reflector to change. In addition to the high-precision temperature control measures adopted by the instrument, materials with matched linear expansion coefficients are often adopted in the design to manufacture the reflector supporting barrel and the reflector supporting back plate. Common mirror support cylinder materials include: 4J32 or 4J36 alloy. The reflector supporting back plate is usually made of aluminum-based silicon carbide which is the same as or higher than the reflector supporting cylinder.

Disclosure of Invention

In order to solve the problem of stress-free support of the large-caliber reflector. The patent provides a design for space heavy-calibre speculum supporting component, tries hard to solve the actual problem in the big-calibre speculum dress school in-process among the present space engineering.

A support assembly for a large aperture spatial reflector comprising: the reflecting mirror support back plate 1, the reflecting mirror support barrel 2, the locking nut 3 and the flexible gasket 4. The axial positioning of the reflector is fixed on the reflector supporting back plate 1 through a locking nut 3 and a stud at the front end of the reflector supporting cylinder 2, and the locking nut 3 is isolated from the reflector through a flexible gasket 4 and used for uniformly locking pressure. The concrete structure is shown in figure 1.

The reflector supporting cylinder 2 is made of 4J32 or 4J36 alloy with the same expansion coefficient.

The reflector supporting back plate 1 is made of the same material of a reflector supporting cylinder or high-component aluminum-based silicon carbide.

The patent is an extension of a central support structure, and a balance is sought between the requirements of optical light blocking rate and optical reflector surface type precision. Although a certain light blocking area is increased, the supporting difficulty of the reflector can be effectively reduced; the accuracy of the assembled rear surface of the reflector is effectively improved. And meanwhile, the reliability of the whole assembly is improved to a certain extent.

The working principle is as follows: the traditional cementing structure is replaced by a mechanical limiting mode. The problem of additional force generated by the adhesive layer to the mirror body due to different expansion coefficients when the adhesive additional stress and the temperature of the adhesive layer are changed is solved. Meanwhile, the reliability of the whole assembly in a resistance mechanical environment test is improved to a certain extent by the traditional mechanical limit. The design is connected to the taper sleeve for the speculum supports and speculum inner bore area of contact increases, and the weight of speculum can the equipartition on the bigger area that supports. The generation of concentrated stress is favorably reduced. The taper sleeve and the reflector body are not glued, so that the whole structure can be conveniently disassembled and assembled in the assembling and correcting process.

The reflector support assembly of this patent has following advantage:

1. the device has the advantages of simple structure and high reliability, and meets the requirement of environment application with harsh space;

2. the design of the supporting piece is effectively simplified, the space is fully utilized, and the utilization rate is improved;

3. the method is simple in implementation steps and easy to guarantee machining precision.

The reflector support assembly of this patent has the disadvantage that the effective clear area is reduced due to the presence of the axial locking nut. But the area is controllable, and the caliber can be increased properly to solve the problem. The selection of the supporting scheme and the requirement of the optical remote sensing instrument on the image quality are determined. This patent is mainly to heavy-calibre speculum, has the design of higher requirement's speculum supporting component to the formation of image quality simultaneously.

Drawings

FIG. 1 is a three-dimensional view of a particular design for a spatial large aperture mirror support assembly;

figure 2 is a cross-sectional view of a specific design for a space heavy caliber mirror support assembly.

Detailed Description

The following detailed description is given with reference to fig. 1 to better illustrate the structural and functional features of the present patent, without limiting the scope of protection of the patent.

The large-caliber reflector supporting assembly of the patent adopts a matching taper sleeve (reflector supporting cylinder 2), and a locking nut 3 is axially locked. The large-aperture reflector adopts a silicon carbide material, and the back part adopts a three-point supporting mode. 3 mounting holes of the reflector are in butt-grinding with the reflector supporting cylinder 2, the reflector mounting holes are preassembled with the reflector supporting cylinder 2, and the reflector supporting cylinder 2 is repaired and ground, so that 3 supporting surfaces are coplanar, and the coplanarity is required to be within 2 mu m. The flatness of the mirror support backplate 1 and the mirror support mounting surface is required to be within 2 μm. When the reflector is installed, the supporting cylinder 2 is installed in the reflector installation hole, and the locking nut 3 is locked. And then installing the back plate, tightening the installation screw, loosening the locking nut 3, and fixing the back plate installation screw by adopting a fixed-torque wrench. And finally, the locking nut 3 is screwed.

Claims

1. The utility model provides a supporting component for space heavy-calibre speculum, includes that the speculum supports backplate (1), a speculum support section of thick bamboo (2), lock nut (3), flexible gasket (4), its characterized in that:

the axial positioning of the reflector is fixed on the reflector supporting back plate (1) through a locking nut (3) and a front end screw column of the reflector supporting cylinder (2), and the locking nut and the reflector are isolated by a flexible gasket (4) and used for uniformly applying locking pressure.

2. A support assembly for a spatial heavy-calibre mirror as claimed in claim 1, wherein: the reflector supporting cylinder (2) is made of 4J32 or 4J36 alloy with the same expansion coefficient.

3. A support assembly for a spatial heavy-calibre mirror as claimed in claim 1, wherein: the reflector supporting back plate (1) is made of the same material of a reflector supporting cylinder or high-component aluminum-based silicon carbide.