JP2015171132A - Membrane reflector and manufacturing method of membrane reflector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a large-sized artificial satellite mounting reflector having high mirror surface accuracy adaptable to high frequency bands.SOLUTION: A membrane reflector includes: a film-like dish forming a mirror surface; a plurality of back ribs supporting the dish from the back side; and a plurality of coupling parts coupling the back ribs and the dish. In the membrane reflector, the dish is formed from a reinforced material of triaxial woven fabric using reinforced fibers as a compound material and a joint portion of the triaxial woven fabric is disposed in parallel with at least one of the back ribs. Thus, a shape of the dish can be restricted and distortion after molding that occurs with the junction portion of the triaxial woven fabric as an origin can be reduced.

Description

  The present invention relates to a membrane reflector with improved mirror surface accuracy of a reflecting mirror.

  In order to reduce the weight, a reflector mounted on an artificial satellite is usually composed of a composite material using reinforcing fibers as a reinforcing material. It is well known that there are various types of reflector structures, such as a sandwich panel method, a dual reflector method, and a mesh method.

  Among these various types of reflectors mounted on satellites, a membrane reflector system has been developed that includes a dish that is a film-like mirror surface and a back structure that supports the dish for further weight reduction.

In the conventional membrane reflector method, the dish serving as the reflector mirror surface portion is thinner than the sandwich panel method corresponding to the high frequency band, and mirror processing after molding cannot be performed. Therefore, conventionally, the membrane reflector system has been used as a reflector for a low frequency band such as the L band that does not require high specular accuracy.
However, with the recent increase in communication data speed and capacity, there is a need for a large artificial satellite-mounted membrane reflector having high specular accuracy corresponding to the high frequency band required for speeding up and capacity increase. .

  Currently, in order to improve the mirror surface accuracy of membrane reflectors mounted on artificial satellites, we manufacture technology that suppresses the use of adhesives with a high coefficient of thermal expansion, which causes a decrease in mirror surface accuracy, and joint components that are difficult to thermally deform Technologies and the like have been established (see, for example, Patent Documents 1 and 2).

However, since these techniques suppress a decrease in specular accuracy due to thermal deformation after exposure to a thermal environment, they are insufficient to support the high frequency band, and to support the high frequency band. The required mirror accuracy cannot be improved.
In order to cope with the high frequency band, it was necessary to improve the mirror surface accuracy of the membrane reflector for satellite installation before being exposed to the thermal environment.

JP 2010-16747 A JP 2008-306567 A

  In the manufacture of a conventional membrane reflector, a dish molded in advance using this mold is placed on a mold having a desired mirror surface shape, and a fixed distance from the back of the placed dish to the mold. Bonding was performed while pressing the bottom surface of the controlled coupling member. Thereby, the shape error from the desired mirror surface shape of the dish is corrected, and the mirror surface accuracy of the membrane reflector is improved.

However, in the case of this manufacturing method, dish distortion occurs irregularly. On the other hand, since the distortion of the area without the back structure cannot be restrained only by the connecting members arranged along the back structure, the mirror surface accuracy of the reflector is low. There was a problem that it would decrease.
In addition, since the shape error of the dish from the desired mirror surface shape increases as the area of the dish increases, there is a problem that the mirror surface accuracy of the reflector decreases as the reflector size increases.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a membrane reflector having high specular accuracy.

  The membrane reflector according to the present invention includes a film-shaped dish that forms a mirror surface, a plurality of back ribs that support the dish on the back side opposite to the reflecting surface of the mirror surface, and the back ribs. The membrane reflector is provided between the dish and is composed of a plurality of connecting portions for connecting the back rib and the dish, and the dish is made of a composite material including a plurality of reinforcing fibers as a reinforcing material. , And a spliced portion where the composite material is spliced is arranged in parallel with the back rib.

  According to the present invention, it is possible to provide a large-sized artificial satellite-mounted membrane reflector having high specular accuracy that can cope with a high frequency band.

1 is an overall view of a membrane reflector according to Embodiment 1. FIG. It is sectional drawing of the coupling | bond part which couple | bonded the dish and back rib which comprise the membrane reflector which concerns on Embodiment 1 using the coupling member. FIG. 3 is a cross-sectional view of the membrane reflector according to Embodiment 1 at the time of dish lamination. FIG. 3 is a top view of the membrane reflector according to Embodiment 1 at the time of dish lamination.

Embodiment 1 FIG.
In the present embodiment, details of the improvement of the mirror surface accuracy of the membrane reflector for satellite installation will be described.
Hereinafter, a membrane reflector 100 according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view showing an example of the structure of the membrane reflector 100. In FIG. 1, a membrane reflector 100 of the present invention includes a film-shaped dish 1 that forms a reflecting mirror surface, a back rib 2 that supports the dish 1 from the non-reflecting mirror surface side (back surface side) that is the convex side of the reflecting mirror surface, It consists of a plurality of coupling members 3 that couple the dish 1 and the back rib 2.

  The dish 1 is a film-like member made of a composite material in which, for example, a biaxial woven fabric using reinforcing fibers or a triaxial woven fabric is used as a reinforcing material, and the back rib 2 is the dish 1 so that the dish 1 acts as a predetermined reflecting mirror. Keep the shape.

  The back rib 2 is a combination of long plate members having a substantially rectangular shape having a width dimension in the axial direction of the membrane reflector 100 (a predetermined direction in the surface of the film-like dish 1) in a triangular truss shape.

FIG. 2 is a cross-sectional view of a joined portion in which the dish 1 and the back rib 2 are joined using the joining member 3.
As shown in FIG. 2, the coupling member 3 is two L-shaped members facing each other. In addition, it is good also as a component which consists of a connection member which connects two L-shaped members and L-shaped members which oppose. In this case, the vertical surfaces corresponding to the vertical surfaces of the L-shaped member are opposed to each other, and the ends of the horizontal surfaces corresponding to the horizontal surfaces of the L-shaped member are connected by a concave connecting member. Become. The back rib 2 and the coupling component 3 are also described in Patent Document 2, for example.

Here, in the dish 1 according to the present embodiment, the joint portions of the fabrics constituting the dish 1 described later are arranged so as to be parallel to at least one of the plurality of back ribs 2. .
In general, the mirror surface error of the reflector increases in the vicinity of the joint portion of the woven fabric. By arranging the joint portion of the woven fabric and the back rib 2 in this manner in parallel, The distortion that occurs can be adjusted, and the specular error can be kept small.

Here, the shaping | molding method of the dish 1 which acts as a reflecting mirror is demonstrated using FIG. FIG. 3 is a view showing a cross section of the dish 1 when the dish 1 is stacked.
In forming the dish 1, first, a mold 4 close to a desired ideal mirror surface is prepared.
A composite material using reinforcing fibers as a reinforcing material, and a material resin (prepreg) in a semi-dry state before the resin is cured is placed on the mold 4.
When the reinforcing fiber of the dish 1 is a woven material, it is a standard product with a width of about 1000 mm due to restrictions on the woven fabric production equipment. When placed on the molding die 4, In general, the width is reduced by cutting. Therefore, the discontinuous surfaces generated by cutting are joined together.
In the dish according to the first embodiment, the joining portion is arranged so as to be parallel to at least one or more back ribs 2 of the back rib 2 bonded to the dish 1 via the coupling component 3 in a subsequent process. To do. And the coupling | bond part 3 is arrange | positioned on the joint part of a reinforced fiber, and the dish 1 and the back rib 2 are fixed via the joint part 3 on a joint part.

FIG. 4 shows a state where two cut prepregs are arranged in the dish 1.
Since the back rib 2 and the connecting member 3 cannot be arranged when the dish 1 is formed, it is desirable to appropriately transfer the position information of the back rib 2 using a positioning jig or the like.
Although it is desirable that all of the joining portions are parallel to any one of the many rear ribs 2, joining portions that cannot be parallel to the rear ribs may occur due to restrictions on the laminating work.
Next, a bagging film is used to form a bag so as to cover the mold on which the semi-dry material resin is placed, and the internal air is extracted using a vacuum pump. In this state, for example, an autoclave is used to pressurize and heat at a predetermined temperature and pressure for a predetermined time. Thereby, the dish 1 having the shape of the mold 4 can be formed.

  Next, a method for joining the dish 1 and the back rib 2 will be described.

  FIG. 2 is a view of the coupling component 3 as seen from the cross-sectional direction. As shown in FIG. 1, the coupling component 3 is arranged with two L-shaped structural portions facing each other. The angles of the two sides of the coupling part 3 vary depending on the position where the coupling part 3 is coupled to the dish, and are prepared in advance so as to have a shape following the desired mirror surface shape at the position where the coupling part 3 is coupled.

Next, a joining procedure using this joining component 3 will be described.
First, an adhesive is applied between the coupling component 3 and the back rib 2 and between the coupling component 3 and the dish 1.
In the state before the applied adhesive is cured, the fixing position of the back rib 2 inserted between the two L-shaped coupling parts 3 is adjusted at each coupling point in the surface of the membrane reflector 100. Next, the adhesive is cured in a state where the reflecting mirror surface formed by the dish 1 has a desired mirror surface shape by the adjustment.
In this way, the entire dish 1, the coupling component 3, and the back rib 2 are fixed.

As described above, in the membrane reflector according to the present embodiment, the dish 1 is arranged so that the joining portion for joining the fabrics that are the material of the dish 1 and the back rib 2 are parallel to each other. And after adjusting so that the shape of the reflector which consists of the dish 1 may become a desired mirror surface shape by adjusting the relative position of the back rib 2 and the coupling | bonding component 3, via the coupling | bonding component 3 in the joint part of a textile fabric. The dish 1 and the back rib 2 were bonded and fixed.
Since the joining parts are arranged on the seam portion of the dish 1, the shape of the dish 1 can be constrained, and distortion after molding that occurs from the seam portion of the dish 1 can be reduced. it can.

  As described above, according to the present embodiment, it is possible to improve the mirror surface accuracy of the membrane reflector, and to provide a large-sized artificial satellite-mounted membrane reflector having high mirror surface accuracy that can cope with a high frequency band.

Note that the dish 1 according to the present embodiment is made of a composite material using a biaxial or triaxial fabric made of reinforcing fibers as a reinforcing material, and at least one of the back ribs 2 is joined to the biaxial or triaxial fabric. However, the discontinuity line of the fiber formed by the cut surface of the reinforcing fiber is parallel to at least one or more of the planar ribs 2 using the dish 1 as a raw material of the composite material of the reinforcing fiber. You may arrange in. In this case, the connecting portion 3 is disposed on the discontinuous line of the fiber formed by the cut surface of the reinforcing fiber, and fixes the dish 1 and the back rib 2 via the connecting portion 3.
Alternatively, the dish 1 is made of a composite material of reinforcing fibers, the reinforcing fibers are arranged next to each other without being overlapped, and the gap between the reinforcing fibers formed when the reinforcing fibers are arranged is parallel to at least one or more of the planar ribs 2. You may arrange | position so that it may become. In this case, the coupling portion 3 is disposed on a gap between adjacent fibers of the reinforcing fiber, and fixes the dish 1 and the back rib 2 via the coupling portion 3.

1 dish, 2 back ribs, 3 connecting members, 4 molds, 100 membrane reflector.

Claims (8)

A film-like dish that forms a mirror surface;
A plurality of back ribs on the back side opposite to the reflecting surface of the mirror surface and supporting the dish;
A plurality of coupling portions that are provided between the back rib and the dish, and couple the back rib and the dish;
A membrane reflector comprising:
The dish is made of a composite material including a plurality of reinforcing fibers as a reinforcing material, and a joining portion obtained by joining the composite materials is arranged in parallel with the back rib.   The membrane reflector according to claim 1, wherein the coupling portion is disposed on the splicing portion.   The membrane reflector according to claim 1, wherein the reinforcing material is a biaxial fabric or a triaxial fabric made of reinforcing fibers. A film-like dish that forms a mirror surface;
A plurality of back ribs on the back side opposite to the reflecting surface of the mirror surface and supporting the dish;
A plurality of coupling portions that are provided between the back rib and the dish, and couple the back rib and the dish;
A membrane reflector comprising:
The dish is made of a composite material of reinforcing fibers, and a discontinuous line of fibers formed by a cut surface of the reinforcing fibers is arranged in parallel with at least one of the back ribs. .   The membrane reflector according to claim 4, wherein the coupling portion is disposed on the discontinuous line. A film-like dish that forms a mirror surface;
A plurality of back ribs on the back side opposite to the reflecting surface of the mirror surface and supporting the dish;
A plurality of coupling portions that are provided between the back rib and the dish, and couple the back rib and the dish;
A membrane reflector comprising:
The membrane reflector is characterized in that a composite material composed of reinforcing fibers is used as a raw material, and a gap between adjacent fibers of the reinforcing fibers is arranged in parallel with at least one of the back ribs.   The membrane reflector according to claim 6, wherein the coupling portion is disposed on the gap. A process of placing a plurality of prepregs before the resin is cured with a composite material including reinforcing fibers as a reinforcing material, and placing them on a mold,
Forming a dish having the shape of the mold by heating the prepreg; and
Placing a coupling member on the seamed portion;
Arranging a back rib along the place where the coupling member is arranged;
Fixing the dish, the arranged coupling member, and the arranged rear rib with an adhesive;
A method for manufacturing a membrane reflector comprising:

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