JPH05183330A - Expansion structure - Google Patents

Abstract

PURPOSE:To obtain the expansion structure with a light weight and high stiffness which is expanded smoothly and forms an optional expansion face. CONSTITUTION:A polygonal closed structure is formed by using hinges 11a, 11b, 11c in the middle, fitting both ends of plural folded members 10a, 10b, 10c formed to be straight lines at the expansion to tips of plural levers 12a, 12b, 12c whose one end is fitted to an apex member 13 and using the folded members 10a-10c. The hinges of the folded members 10a-10c and the apex member 13 are linked by expansion/contraction members 14a, 14b, 14c and an actuator expanding/contracting the expansion member in the axial direction is provided to at least one of the expansion members.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deployable structure for constructing a back structure or the like in an antenna mounted on an artificial satellite.

[0002]

2. Description of the Related Art With the full-scale utilization of space, antennas mounted on artificial satellites are required to have higher gains, and also high gains are used for communication, broadcasting, energy transmission, earth observation and astronomical observation. The demand for antennas is widespread.

The increase in the gain of the antenna structurally means an increase in the diameter, and there are two technical problems to be solved in increasing the diameter of the antenna. That is, one is the weight, and the other is the problem of the fairing size of the launch vehicle.In order to secure the strength and rigidity to withstand the vibration during launch, the structural weight suddenly increases as the caliber increases. The size of structures that can be increased and loaded into the rocket is limited by the fairing size of the rocket.

By the way, these two problems can be solved at the same time by adopting a deployment structure in which the antenna is folded into a small size at the time of launch and automatically expanded to the final shape on the orbit by a mechanism incorporated in the antenna.

Various methods have been proposed as the expansion structure, but the mesh surface expansion type is generally suitable for the expansion diameter exceeding 10 m, although it depends on the target frequency. This is for forming the antenna reflector surface with a mesh material, and one of the structures that holds the mesh material is a deployable truss structure, which has triangular pyramids, cubes, etc. as basic constituent elements.

FIG. 9 is a diagram showing the basic constituent elements of a conventional deployable truss structure, and as shown in (c1) and (c2) thereof, three upper surface members 1 having a hinge 1a in the center thereof.
Are sequentially connected by a spider joint 2 to form a triangle. One end of each of the spider joints 2 is connected to the other end of a slant member 4 attached to another spider joint 3.

However, during storage (a1) and (a
The upper surface member 1 and the slant member 4 which are bent as shown in 2)
Is converged, the converged state is released at the time of expansion, and the elastic force of a spring (not shown) attached to the hinge 1a or the spider joints 2 and 3 causes the upper surface member 1 to move.
Is unfolded to form a straight line, and the state shown in FIGS. 9C1 and 9C2 is obtained. 9 (b1) and (b2) show a state in the middle of development.

Therefore, such a basic element is shown in FIG.
An antenna back structure truss can be formed by combining a large number as shown in FIG.

[0009]

However, in the apparatus constructed as described above, since the expansion is caused by the elastic energy of the spring attached to the hinge or the spider joint of the upper surface member, the nonlinearity of the spring and Due to the influence of variations in each spring, a certain portion may be deployed early or a certain portion may be delayed in deployment, and the deployment may be performed while taking an irregular shape. Unexpected forces may be exerted on such members that are not aligned with their surroundings, possibly locking them and preventing further deployment.

Further, when the back structure of the antenna reflecting mirror surface is formed by the conventional deployed truss structure, many basic truss structures are combined, and grating lobes are generated due to the periodicity of the basic truss. However, there is also a problem that this becomes a large interference wave to the surroundings.

In view of the above points, an object of the present invention is to obtain a deployable structure which is lightweight, has high rigidity, can smoothly deploy, and can form an arbitrary deploying surface.

[0012]

SUMMARY OF THE INVENTION According to the present invention, a plurality of bending members each having a hinge at a central portion thereof and having a linear shape when deployed have a plurality of bending members whose base ends are pivotally attached to one top member. Is pivotally attached to the tip of the lever, a polygonal closed structure is formed by this bending member, and the hinge part of each bending member and the top member are connected by an expansion member, and at least one of the expansion members. Further, a driving device for axially expanding and contracting the elastic member is provided.

Further, in the second invention, the line connecting the center lines of the pivotal portions of the levers and the elastic members to the top member is similar to the polygon formed by the bending members. It is characterized by being.

[0014]

When the elastic member is contracted, each bending member is bent in two at the central hinge portion, whereby each lever swings about the pivot point of the top member and each lever and The folding members are converged into one rod. Therefore, when the elastic member is extended by the driving device, the bending member is expanded and the polygonal closed structure is formed by the bending members that are linear, and the expanded state is achieved.

Further, since the line connecting the center lines of the pivots of the levers and the elastic members to the top member is similar to the polygon formed by the bending members, the same size is obtained in the entire length when they converge. It becomes the cross-sectional shape.

[0016]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of a regular tetrahedron unfolding structure which is one of the basic constituent elements for forming the unfolding truss structure. Reference numerals 10a, 10b and 10c in the drawing respectively indicate hinges at the central portions. Bending members of the same length having 11a, 11b, 11c that are linear when deployed, one end of each of the bending members 10a and 10b being pivotally attached to the tip of the lever 12a. The other end and one end of the bending member 10c are pivotally attached to the tip of the lever 12b. Further, the other end of the bending member 10a and the bending member 1
The other end of 0c is pivotally attached to the tip of the lever 12c, and the folding members 10a, 10b, 10c are sequentially connected via the tip portions of the corresponding levers 12a, 12b, 12c to form a triangular closed structure. I am doing it.

The base ends of the levers 12a, 12b, 12c are both pivotally attached to one top member 13, and when the bending members 10a, 10b, 10c are straight, that is, at the time of unfolding, Book levers 12a, 12b,
A triangular pyramid is formed by 12c and three bending members 10a, 10b, 10c.

On the other hand, the bending members 10a, 10b, 10c
Each of the hinges 11a, 11b, 11c is connected to the tips of the elastic members 14a, 14b, 14c that can expand and contract in the axial direction, respectively.
The base end of 4c is pivotally attached to the top member 13.

Each of the elastic members 14a, 14b, 14c is composed of a tubular member and a rod member that slides inside the tubular member. The elastic members 14a, 14b, 1
At least one of 4c is provided with a drive device that extends or expands or contracts the elastic member in the axial direction.

FIG. 3 is a partial cross-sectional view showing a telescopic member portion having the driving device, and FIG. 4 is a plan view of the top member. The base members of the levers 12a, 12b, 12c have a triangular top member 13. Are rotatably pivoted in the respective corners of the base in the radial direction, and the base ends of the elastic members 14a, 14b, 14c are respectively pivoted in the radial direction at the centers of the sides of the triangular top member 13. Possibly pivoted. That is, each lever 12
a, 12b, 12c and elastic members 14a, 14b, 1
The line connecting the centers of the pivotal portions of 4c to the top member 13 has a shape similar to the triangular expansion surface formed by the bending members 10a, 10b, 10c.

The elastic member 14a has a tubular member 15 whose base end is pivotally attached to the top member 13, and receives an external signal (not shown) from the tubular member 15 to axially move the elastic member. An actuator 16 that drives extension or extension is incorporated. A ball screw shaft 19 is connected to a rotary shaft 17 of the actuator 16 via a coupling 18, and the ball screw shaft 19 has one end bent at the bending member 1
It is inserted into the second tubular member 20 pivotally attached to the hinge 11a of 0a, and is screwed into the female screw 21 fixedly mounted on the second tubular member 20.

On the other hand, an inwardly projecting projection 22 is provided at the tip of each lever 12a, 12b, 12c, and the end of each bending member 10a, 10b, 10c is pivotally attached to this projection 22. It is worn.

Next, the unfolding operation of this unfolding structure will be described. First, the tetrahedron unfolding structure is folded as shown in FIG. 2 (A) or FIG. 3, and in this folded state, the elastic members 14a, 14b, 14c are contracted, and the folding members 10a, Hinge 10b and 10c
1a, 11b, 11c are bent, and each lever 12
It is stored in a bundle with a, 12b, and 12c.

Therefore, when a driving signal is externally sent to the actuator 16 incorporated in at least one of the elastic members 14a, 14b, 14c to drive the actuator 16, the rotary shaft 17 and the coupling are driven by the actuator 16. The ball screw shaft 19 is rotated via 18. Therefore, this ball screw shaft 1
Second tubular member 2 via female screw 21 screwed to 9
0 moves in the axial direction, the elastic member 14a starts to expand, the hinge 11a is pushed down accordingly, the bending member 10a is expanded, and the levers 12a, 12c are moved along with the movement of the bending member 10a. Is expanded outward, and at the same time, the bending members 10b and 10c are expanded, and the lever 10b is expanded.
Is also pushed outward (see FIG. 2 (B)).

In this way, the elastic members 14a, 14b,
14c extends and each bending member 10a, 10b, 10c
When the bending member 1 becomes straight, the state shown in FIG.
0a, 10b, 10c and levers 12a, 12b, 12
A regular tetrahedron is formed with c and is in a developed state. In this unfolded state, the straight bending members 10a, 10b, 10c forming the triangular surface are supported by three members, respectively, and the unfolded structure has high rigidity.

Although the regular tetrahedral expanded structure, which is the most basic structure, has been described above, expanded structures such as a pentahedron and a hexahedron can be constructed in the same manner.

That is, FIG. 5 is a diagram showing a pentahedral unfolding structure in the unfolded state, in which four bending members 10a, 10 are shown.
b, 10c, 10d and four levers 12a, 12b, 1
2c, 12d and four elastic members 14a, 14b, 14
By using c and 14d, the expanded structure can be constructed in the same manner as in the first embodiment. 6 and 7 are views showing the unfolding operation state.

Further, the above-mentioned both embodiments show basic constituent elements constituting the deployable truss structure, and a plurality of these can be combined, and in this case, an arbitrary deployed shape is formed depending on the number to be combined and the arrangement configuration. be able to.

That is, FIG. 8 is a view showing an example in which a deployable truss structure is formed by a plurality of deployable structures having different shapes. One having a hexagonal deployable surface 30 and 6
This is a combination of a quadrilateral and a triangular development surface 40, 50. By randomly arranging arbitrary polygons in this way, it is possible to prevent the generation of grating lobes that occur due to the periodicity of the basic configuration.

Further, in the above embodiment, a motor can be used as the actuator of the expansion / contraction member, and in this case, it is possible to automatically fold the motor from the unfolded state by rotating the motor in the reverse direction, and it is not completely unfolded. It is also possible to stop the driving in the middle of the development and keep the state. Further, a spring or the like may be used as the actuator.

The deployable structure of the present invention can be used not only in the above-mentioned antenna back structure but also in various fields such as a frame structure of an outdoor tent.

[0033]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it can be folded in a lightweight and compact form, and can be smoothly deployed from this folded state, and a deployable product with high rigidity can be constructed. Folding-unfolding can be done easily. Further, since the basic developed shape can be arbitrarily configured as a triangle, a quadrangle, a pentagon, a hexagon, etc., a desired shape can be configured by combining a plurality of basic configurations. In particular, for example, when constructing an antenna mirror-back structure of a large-diameter antenna for space, it is possible to randomly arrange any polygon instead of combining one basic configuration as in the conventional case, It is possible to prevent the generation of grating lobes that occur due to the periodicity of the basic configuration, and obtain a high-performance large-diameter deployable antenna that does not generate interfering radio waves. In addition, depending on the combination method, a large-scale deployable structure having partially different rigidity can be configured, and the deployable structure having the most efficient member configuration can be obtained. Furthermore, if the line connecting the center lines of the pivotal parts to each lever and the elastic member is made to have a similar shape to the development surface formed by the bending member, the respective cross-sectional shapes in the axial direction at the time of convergence are set. They can be the same, and their outer shape can be made compact. Further, in the case where a motor is used as the actuator, the actuators can be operated in synchronization when a plurality of deploying structures are combined, and there is no delay in deploying some of them.

[Brief description of drawings]

FIG. 1 is a conceptual structural diagram showing an embodiment of a developed structure of the present invention.

2A and 2B are explanatory diagrams of a deployment operation state of the deployment structure shown in FIG. 1, where FIG. 2A is a converged state and FIG. 2B is a diagram showing a state in the middle of the deployment operation.

FIG. 3 is a partially enlarged cross-sectional view showing the expanded structure in a converged state.

FIG. 4 is a plan view of the top member.

FIG. 5 is a conceptual structural diagram of another embodiment of the present invention.

FIG. 6 is an explanatory view of the expanded state of the expanded structure shown in FIG.

FIG. 7 is an explanatory view of a deployed state of the deployed structure shown in FIG.

FIG. 8 is a diagram showing an example of a developed structure formed by combining a plurality of developed structures.

FIG. 9 is a conceptual structural diagram of a conventional deployment structure,
1), (b1) and (c1) are plan views for explaining the deployment operation, and (a2), (b2) and (c2) are side views thereof.

FIG. 10 is a diagram in which a plurality of the developed structures of FIG. 9 are combined.

[Explanation of symbols]

 10a, 10b, 10c Bending member 11a, 11b, 11c Hinge 12a, 12b, 12c Lever 13 Top member 14a, 14b, 14c Elastic member 15 Cylindrical member 16 Actuator 19 Ball screw shaft 20 Second tubular member 21 Female screw

Claims (2)

[Claims] 1. A plurality of levers each having a base end pivotally attached to one top member, and a plurality of levers pivotally attached to a tip end portion of each lever to connect the tip end portions of each lever to form a polygonal closed structure. A plurality of bending members that have a hinge in the central portion and become linear when deployed, one end of which is connected to the hinge portion of each of the bending members, and the other end is an elastic member that is pivotally attached to the top member, A deployable structure, comprising: a drive device that is provided in at least one of the elastic members and that expands and contracts the elastic member in the axial direction. 2. A line connecting the center lines of the respective pivots of the lever and the elastic member to the top member is similar to the polygon formed by the bending member. The expanded structure according to claim 1.