CN112164883B - A layered feed structure for maintaining sub-layer pressure in a temperature-changing environment - Google Patents

Abstract

A layered feed structure for keeping the pressure between sub-layers in a temperature-varying environment belongs to the technical field of satellite-borne antennas. The horn array and the polarizer array are arranged in a laminating way and are fixedly connected through a plurality of fasteners, and the polarizer array is arranged at the bottom of the horn array; a combination body formed by the horn array and the polarizer array is arranged at the top of the beam forming network; the beam forming network comprises a plurality of layer network layered cavities; the plurality of layer network layered cavities are stacked and installed and are connected and fixed through a plurality of fasteners; each fastener comprises an active section and a column section; the column section penetrates through a through hole arranged on the network layered cavity, and a thermal compensation gasket is arranged between the active section and the nearest network layered cavity and is used for compensating the deformation of the network layered cavity when the environment is subjected to temperature change, so that the problems that the electrical performance of a feed part is reduced and the like caused by the variation of the pretightening force of a fastener between layer connection structures under an extreme temperature condition are solved in principle.

Description

A layered feed structure for maintaining sub-layer pressure in a temperature-changing environment

technical field

The invention relates to a layered feeding structure for maintaining the pressure between sublayers in a temperature-variable environment, and belongs to the technical field of space-borne antennas.

Background technique

The structure of the antenna feeding component is complex, and it usually adopts a split-type split processing form, and then uses fasteners (screws, washers, etc.), positioning pins, etc. to assemble the split structure into a whole for use. The antenna feeding components are usually made of aluminum alloy, while the fasteners are made of alloy steel. When working in orbit, there will be extreme temperature states of high temperature and low temperature in the shadow area caused by sunlight and the occlusion of the satellite cabin (such as synchronous orbit). The high and low temperature of the feed components of communication satellites can reach -130℃～+140℃), because the thermal expansion coefficients of aluminum alloy materials and steel materials are inconsistent, so in extreme temperature environments, especially cold shrinkage at low temperatures, the feed components body The size is smaller than that of the fastener connection, and the pre-tightening force of the fastener decreases, which is likely to bring about technical problems such as electromagnetic wave leakage, micro-discharge and PIM.

In order to solve the above problems, the traditional design method is to use a high-voltage flange with a choke groove in the connection of the feeder components, reduce the pressing area, increase the pressure between the connection surfaces, or partially open the flange around the end face. When the fasteners are pressed, additional stress deformation occurs near the grooved part of the outer ring of the flange, which improves the pressing margin under the temperature change environment. The problem with the traditional design method is: in principle, it does not have the ability to maintain a constant pressure on the connection surface in a high and low temperature environment, and the retention ability of the screw pre-tightening force applied in a normal temperature environment during operation cannot be tested and evaluated in a high and low temperature environment. Screening for electrical performance tests in high and low temperature environments; in addition, with the wide application of feed components for higher frequency complex cavities, there is no space for choke slots in small-scale multi-level laminated thin-walled structures, and traditional choke The trough type of high pressure flange is not possible by design.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is: overcoming the deficiencies of the prior art, providing a layered feeding structure that maintains the pressure between sublayers in a temperature-changing environment, introducing thermal compensation washers made of invar, through different materials The interlayer thermal expansion coefficient matching and connection length compensation method balances the layered structure of the aluminum alloy and the thermal expansion coefficient of the connecting screw, which can ensure that the interlayer preload force is approximately constant in any temperature-changing environment, so that the power feeding under different temperature conditions The interlayer pressure of components has become a quantitative index, which in principle solves the problems of electromagnetic leakage, micro-discharge and passive intermodulation of feeder components caused by changes in the pre-tightening force of fasteners between laminated structures caused by temperature changes.

The technical solution of the present invention is: a layered feeding structure that maintains the pressure between sublayers in a temperature-changing environment, including a synthetic multi-beam feed array; the synthetic multi-beam feed array includes a horn array, a polarizer Arrays, beamforming networks, fasteners and thermal compensation washers;

The horn array and the polarizer array are stacked and installed, and are connected and fixed by several fasteners, and the polarizer array is installed at the bottom of the horn array; the combination formed by the horn array and the polarizer array is installed on the top of the beamforming network ;

The beamforming network includes several layers of network layered cavities; the several layers of network layered cavities are installed in layers and connected and fixed by several fasteners;

Each of the fasteners includes an active section and a column section; the column section passes through a through hole installed on the network layered cavity, and thermal compensation is provided between the active section and the network layered cavity closest to it Gaskets are used to compensate for the deformation of the network layered cavity when the temperature changes in the environment.

Further, the material of the thermal compensation gasket is a material with thermal expansion coefficient≤5.0e- ⁶ /℃.

Further, the material of the thermal compensation washer is Invar.

其中，L₁为波束形成网络若干层网络分层腔体层联结构的长度，α₁为波束形成网络材料的热膨胀系数，α₂为热补偿垫圈材料的热膨胀系数，α₃为紧固件材料的热膨胀系数。Further, the height of the thermal compensation washer is

Among them, L ₁ is the length of the multi-layer network layered cavity layered structure of the beam-forming network, α ₁ is the thermal expansion coefficient of the beam-forming network material, α ₂ is the thermal expansion coefficient of the thermal compensation gasket material, and α ₃ is the fastener material the thermal expansion coefficient.

Further, the column segments of the fasteners pass through 1-4 layers of network layered cavities as required.

Further, the column section of the fastener passes through the horn array and is screwed to the polarizer array.

Further, the column segments of the fasteners pass through the polarizer array and are screwed to the beamforming network.

Further, in the hot and cold environment of the spaceborne antenna, the network layered cavity uses fasteners combined with thermal compensation washers to apply a pre-tightening force to keep the pressure between the network layered cavity layered structures unchanged, preventing electromagnetic leakage of feed components , as well as improved PIM and microdischarge margins.

The advantages of the present invention compared with the prior art are:

1. The thermal compensation gasket made of metal material with low thermal expansion coefficient (invar) is innovatively introduced. Through the matching of material thermal expansion coefficient (α) and connection length (L), the layer caused by temperature change is solved in principle. Electromagnetic leakage, micro-discharge and passive intermodulation problems of feeder components caused by changes in the pressing force of fasteners between connecting structures;

2. The invention keeps the preset fastener pre-tightening force under normal temperature conditions unchanged under high and low temperature conditions, avoiding the previous evaluation method that relies on testing and screening under high and low temperature conditions of the test piece, and also avoids the test conditions. It is difficult to evaluate the application environment of products below -160 ℃ that is difficult to achieve;

3. The invention is simple and reliable in calculation, and has a wider range of applications. It can be implemented as long as there are fastener installation controls, avoiding constraints such as the need for large space in the design of high-pressure flanges of choke grooves.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is the structural disassembly schematic diagram of the present invention;

FIG. 3 is a schematic structural diagram of the thermal compensation washer of the present invention.

Detailed ways

In order to better understand the above technical solutions, the technical solutions of the present application will be described in detail below through the accompanying drawings and specific embodiments. It is not a limitation on the technical solutions of the present application, and the embodiments of the present application and the technical features in the embodiments may be combined with each other under the condition of no conflict.

The following is a further detailed description of a layered feed structure for maintaining sub-layer pressure in a temperature-variable environment provided by the embodiments of the present application with reference to the accompanying drawings. :

In the solution provided by the embodiment of the present application, the present invention includes: a composite multi-beam feed array 1; the composite multi-beam feed array 1 includes a horn array 2, a polarizer array 3, a beam forming network 4, a fastener 5 and thermal compensation washer 6.

Further, in the solution provided in the embodiment of the present application, the speaker array 2 and the polarizer array 3 are stacked and installed, and are connected and fixed by several fasteners 5, and the polarizer array 3 is installed at the bottom of the speaker array 2; The combination body formed by the horn array 2 and the polarizer array 3 is installed on the top of the beamforming network 4; the beamforming network 4 includes several layers of network layered cavities; the several layers of network layered cavities are stacked and installed, and It is connected and fixed by a number of fasteners 5; each of the fasteners 5 includes an active segment and a column segment; the column segment passes through the through holes installed on the network layered cavity, and the active segment is connected to the network closest to it. A thermal compensation gasket 6 is arranged between the layered cavities to compensate for the deformation of the network layered cavities when the temperature changes in the environment.

In a possible implementation, the traditional flat washers and spring washers are replaced by thermal compensation washers in the fastener connection link, so that the pre-tightening force of the fasteners remains unchanged under high and low temperature environments, and the inter-layered structures Always keep the preset pressing force, the thermal compensation gasket adopts 4J32 (YB/T5241-2005) invar material (the thermal expansion coefficient of the material below 200℃ is less than 2.0e-6/℃), and the thermal expansion coefficient of the invar material is lower It can calculate the height dimension (variable) of the thermal compensation washer, and by increasing the length of the steel connection screw, the aluminum alloy layered connection structure and the length change dimension of the steel screw under different temperature conditions are approximately consistent, and then the The purpose of synthesizing the different components of the multi-beam feed array 1 and each layer of the beam forming network 4 maintains a certain pressure and pressing force.

In a possible implementation, as shown in Figure 3, under normal temperature conditions, a torque wrench is used to apply a pre-tightening force between the layers of the network through fasteners, at this time:

L ₂ =L ₁ +L ₃

In the rail temperature environment T (°C), the temperature gradient is defined as ΔT=T-20 (normal temperature) (°C), and the change of the connection length between the layers of the network under this temperature gradient is ΔL ₁ , and the change of the length of the connecting screw is ΔL ₂ , the change in thermally compensated washer length is ΔL ₃ :

ΔL ₁ =L ₁ ×α ₁ ×ΔT; ΔL ₂ =L ₂ ×α ₂ ×ΔT; ΔL ₃ =L ₃ ×α ₃ ×ΔT

Among them: α _i (i=1, 2, 3) are the thermal expansion coefficients (10-6/°C) of the network, connecting screws, and thermal compensation gasket materials, respectively.

Under the same temperature gradient, in order to keep the pressure and compression force of each connection layer of the network approximately constant, the sum of the change of the length of each connection layer of the network and the change of the length of the thermal compensation washer should be equal to the length change of the connecting screw. , then there are:

ΔL ₂ =ΔL ₁ +ΔL ₃

That is: L ₂ ×α ₂ ×ΔT=L ₁ ×α ₁ ×ΔT+L ₃ ×α ₃ ×ΔT

Since the connection layers of the network are closely connected, and the temperature gradients of each component are equal, the pressure and compression force between the network layers are only related to the thickness of the network connection layer, the height of the thermal compensation washer, the connection length of the screw and the thermal expansion coefficient of the above-mentioned materials. , which has nothing to do with the value of the temperature gradient, thus ensuring the design goal of approximately constant compression force between layers of the network under any temperature conditions within the orbital operating temperature range.

In one possible implementation, since the network layered structure length (L ₁ ), the fastener length (L ₂ ), and the material thermal expansion coefficient are all known quantities, two calculation variables are involved, namely the thermally compensated gasket The calculation formulas of the height (L ₃ ) and thermal expansion coefficient (α ₃ ) are as follows:

Where: α ₁ : thermal expansion coefficient of composite multi-beam feed material aluminum alloy 6061;

α ₂ : thermal expansion coefficient of thermal compensation gasket low-expansion alloy 4J32;

α ₃ : Coefficient of thermal expansion of steel connecting screws.

It can be seen from the above formula that the smaller the thermal expansion coefficient (α ₃ ) of the thermal compensation gasket, the smaller the height (L ₃ ) of the thermal expansion gasket, and the more compact the size of the connection structure. Therefore, Invar material 4J32 is the preferred material for making thermal compensation gaskets. Other materials with lower thermal expansion coefficients, such as composite materials, can also achieve the same or similar function as thermal compensation gaskets.

Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims (6)

1. A layered feed structure for keeping pressure between sub-layers in temperature-varying environment is characterized in that: comprises a synthesis multi-beam feed array (1); the synthetic multi-beam feed array (1) comprises a horn array (2), a polarizer array (3), a beam forming network (4), a fastener (5) and a thermal compensation washer (6);

the loudspeaker array (2) and the polarizer array (3) are mounted in a stacked mode and are fixedly connected through a plurality of fasteners (5), and the polarizer array (3) is mounted at the bottom of the loudspeaker array (2); the loudspeaker array (2) and the polarizer array (3) are combined and arranged at the top of the beam forming network (4);

the beam forming network (4) comprises a plurality of layers of network layered cavities; the plurality of layer network layered cavities are stacked and installed and are connected and fixed through a plurality of fasteners (5);

each fastener (5) comprises an active section and a column section; the column section penetrates through a through hole arranged on the network layered cavity, and a thermal compensation gasket (6) is arranged between the active section and the network layered cavity closest to the active section and is used for compensating the deformation of the network layered cavity when the environment is subjected to temperature change;

the thermal compensation washer (6) is made of a material with a thermal expansion coefficient less than or equal to 5.0e ^-6 Materials at/° c;

the thermal compensation washer (6) is made of invar steel.

2. The layered feed structure for maintaining pressure between sub-layers in a temperature-varying environment according to claim 1, wherein: the height of the thermal compensation gasket (6) is

Wherein L is ₁ Length of layered cavity hierarchy for several layers of network of the beam forming network (4), alpha ₁ Is the thermal expansion coefficient, alpha, of the material of the beam forming network (4) ₂ Is the thermal expansion coefficient, alpha, of the material of the thermal compensation washer (6) ₃ Is the coefficient of thermal expansion of the material of the fastener (5).

3. The layered feed structure for maintaining pressure between sub-layers in a temperature-varying environment according to claim 1, wherein: the column section of the fastener (5) penetrates through the 1-4-layer network layered cavity as required.

4. The layered feed structure for maintaining pressure between sub-layers in a temperature-varying environment according to claim 1, wherein: the column section of the fastener (5) penetrates through the horn array (2) and is in threaded connection with the polarizer array (3).

5. The layered feed structure for maintaining pressure between sub-layers in a temperature-varying environment according to claim 4, wherein: the column section of the fastener (5) passes through the polarizer array (3) and is screwed to the beam forming network (4).

6. The layered feed structure for maintaining sub-layer pressure under temperature-varying environment according to any one of claims 1 to 5, wherein: under the cold and hot environment of the satellite-borne antenna, the network layered cavity applies pretightening force by using a fastener (5) in combination with a thermal compensation gasket (6) to keep the pressure between layered structures of the network layered cavity unchanged, prevent the electromagnetic leakage of a feed part and improve PIM and micro discharge margin.

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