JPH07187094A - Separation mechanism for space structure - Google Patents

Abstract

PURPOSE:To couple and separate structure bodies to and from each other safely and accurately, regardless of a lightweight and small structure. CONSTITUTION:This separation mechanism is constituted of a bolt 3 for coupling a pair of structure bodies 1 and 2 to each other, a housing 5 formed on one of the bodies 1 and 2, a radially divided separation nut 4 laid in the housing 5 and screwed to the bolt 3, a shape memory alloy coil 6 wound around the external surface of the nut 4 and having each end connected to a heater 7 via the housing 5, and a bolt pushing spring 9 laid between the end of the bolt 3 and the inner wall of the housing 5 for pressing the bolt 3 to the structure bodies 1 and 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a space structure separating mechanism such as a multistage rocket, and more particularly to a space structure separating mechanism using a shape memory alloy.

[0002]

2. Description of the Related Art Conventionally, for disconnecting multi-stage rockets, etc. between stages and for separating artificial satellites, etc., a pyrotechnic product is provided at the connecting portion of each structure, and the pyrotechnic product is detonated by the impact force. The method of separating each structure was adopted.

A conventional separating mechanism for space structures using pyrotechnics will be described with reference to FIG. 3A and 3B are cross-sectional views of a main part showing a separation mechanism of a conventional space structure. FIG. 3A shows a state at the time of coupling and FIG. 3B shows a state at the time of separation. In these figures, 1 and 2 are a pair of space structures to be coupled and separated, for example, a first stage rocket and a second stage rocket of a multistage rocket. Reference numeral 3 is a bolt that connects the structures 1 and 2 by penetrating holes provided in the pair of structures 1 and 2, respectively. Reference numeral 14 is a separation nut with which the bolt 3 is screwed, and as shown in the figure, has a structure in which it is divided into two in the radial direction at the axial center plane. Also, this separation nut 14
It has irregularities on the outer circumference.

Reference numeral 15 denotes a housing which surrounds the separation nut 14, and is fixed to one of the pair of structures 1 and 2 (structure 1 in FIG. 2) by a screw 10. A piston 16 is provided on the inner wall of the housing. It is arranged. This piston 1
6 has irregularities in the inner circumferential direction, and when the convex portion abuts the convex portion of the separation nut 14, the separation nut 14 is tightened by the piston 16 and the bolt 3 is tightened integrally to tighten the piston 3. When the protrusion 16 of the piston 16 and the recess of the separation nut 14 are fitted with each other by shifting the shaft 16 in the axial direction, the separation nut 14 is separated. 17
Is a pyrotechnic product provided on the side surface of the housing 15 in the axial extension direction of the bolt 3.

In the conventional space structure separating mechanism having such a structure, the separating nut 14 integrated by the bolt 3 and the piston 16 is screwed in the normal state shown in FIG. 3A. , Structures 1 and 2 are firmly connected. When the structures 1 and 2 are separated, first, the pyrotechnic 17 is exploded and the impact force pushes the piston 16 in the housing 15 forward (to the right in the drawing). When the piston 16 is pushed forward, the protrusion of the piston 16 and the protrusion of the separation nut 14 are disengaged from each other and the piston 16
Of the separating nut 14 into the concave portion of the separating nut 14,
Since the tightening is released, the separation nut 14 separates in the vertical direction in the drawing. On the other hand, the bolt 3 is also pushed backward (to the right in the drawing) by the impact force of the explosion of the pyrotechnic 17,
As a result, the bolt 3 and the separation nut 14 are unscrewed,
The structures 1 and 2 will be separated immediately.

In this conventional space structure separating mechanism, since the structures are separated by the impact force caused by the explosion of pyrotechnics, the impact force gives a strong vibration to the structure, and in the worst case, each structure is separated. There was a risk of destroying or damaging the object. Therefore, in the conventional space structure separation mechanism, it is necessary to provide a damping structure or other reinforcing means around each structure, especially around the joint portion, and increase the weight of the space structure or This has led to higher costs.

In view of this, according to Japanese Unexamined Patent Publication No. 60-61400, a connecting plate made of a shape memory alloy material is deformed at a specific temperature to bond the respective structures without using pyrotechnics, and the bonded portions are joined together. A structure coupling device has been proposed which is configured to return the shape memory alloy material to the shape before deformation by heating or cooling from a specific temperature to above the martensite transformation temperature, thereby releasing the bond of the structure. There is.

[0008]

However, the structure joining apparatus described in JP-A-60-61400 is adapted to the transformed shape of the connecting plate made of the shape memory alloy material at the joining portion of each structure. Since it is necessary to separately provide a special structure, there is a problem that the space structure becomes rather heavy, complicated, and expensive. Further, in this structure joining device, the structures are joined only by providing the connecting plates of the small pieces at two places, so there is concern about the joining force. Further, in this structure joining device, the joining is released by the transformation of the shape memory alloy material.
It took some time to release, and it was difficult to deal with the separation of space structures that required instantaneous separation.

The present invention has been proposed in order to solve the problems of the prior art as described above, and has a lightweight and small structure without the need for pyrotechnics and other complicated structures. It is an object of the present invention to provide a space structure separation mechanism that enables safe, reliable, and quick connection and separation of structures.

[0010]

In order to achieve the above object, a space structure separating mechanism according to the present invention comprises a bolt for connecting a pair of structures and a housing provided on one of the pair of structures. And is provided inside this housing,
A radially separated split nut that is screwed into the bolt, a shape memory alloy coil that is wound around the outer circumference of the split nut in a coil shape, and has each end connected to a heater through the housing, and the bolt. It is provided between the tip and the inner wall of the housing and is composed of a bolt pushing spring that presses the bolt toward the structure side, and preferably the separation nut is divided into two in the radial direction at the axial center plane. It is as a configuration. In addition, a spring for pulling the separation nut in the radial direction is provided between the side surface of the separation nut and the inner wall of the housing, if necessary.

[0011]

According to the space structure separating mechanism of the present invention having the above-described structure, the structure is firmly connected by the screwing of the separation nut and the bolt fastened to the shape memory alloy coil at the time of connection, and the shape memory at the time of separation. When the inner diameter of the alloy coil is increased, the separation nut is pulled by the spring to be divided, and the bolt is also pushed out by the spring to release the screw engagement, so that the structure is instantaneously separated.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the space structure separating mechanism of the present invention will be described below with reference to the drawings. FIG. 1A is a cross-sectional view of an essential part showing a state when a space structure separating mechanism according to an embodiment is coupled, and FIG. 1B is a perspective view showing a state where a separating nut is integrated. FIG. 2A is a cross-sectional view of an essential part showing a state at the time of separation of an embodiment of a space structure separation mechanism,
FIG. 2B is a perspective view showing a state where the separation nut is separated. In the figure, 1 and 2 are a pair of space structures to be coupled and separated, such as a first stage rocket and a second stage rocket in a multistage rocket. 3 passes through the holes provided in the pair of structures 1 and 2, respectively.
Is a bolt that joins. Reference numeral 4 denotes a separation nut that is screwed with the bolt 3 and has a structure that is divided in the radial direction. In this embodiment, the separating nut 4 is divided into two parts at the axial center plane.

Reference numeral 5 denotes a housing which surrounds the circumference of the separation nut 4, and is fixed to one of the pair of structures 1 and 2 (structure 1 in this embodiment) by a screw 10.
Reference numeral 6 denotes a shape memory alloy coil wound around the outer circumference of the separation nut 4 in a coil shape, and each end portion is connected to the heater 7 via the housing 5. The shape memory alloy coil 6 has a shape memorized with a diameter larger than the outer diameter of the separation nut 4, and is deformed at a low temperature so that the inner diameter is the same as or slightly smaller than the outer shape of the separation nut 4. .

Reference numeral 8 denotes a tension spring stretched over the side surface of the separation nut 4 and the inner wall of the housing 5, and the separation nut 4
The separation nut 4 is always pulled on the inner wall side of the housing 9 in the direction perpendicular to the axial surface of. In this embodiment, since the separation nut 4 has a two-part structure, the nut spring 8
Is configured to pull the separation nut 4 in the radial direction (vertical direction in the drawing).

In this embodiment, the tension spring 8
Are provided at two locations in the radial direction, respectively, but the invention is not limited to this. Reference numeral 9 denotes a bolt pushing spring provided between the bolt 3 and the inner wall of the housing 5, and always pushes the bolt 3 toward the structure 1.

The space structure separating mechanism of this embodiment having such a structure operates as follows. Normally, when the structures 1 and 2 are connected, the shape memory alloy coil 6 is deformed at a low temperature to tighten the separation nut 4, so that the bolt 3 and the separation nut 4 are screwed together to form the structure. Thing 1
And 2 are tightly bound.

When the structures 1 and 2 are separated, the shape memory alloy coil 6 is energized via the heater 7 to heat the shape memory alloy coil 6. The heated shape memory alloy coil 6 is restored to a memorized shape, that is, a shape having a diameter larger than the outer diameter of the separation nut 4 when the restoration temperature is reached.
As a result, the separation nut 4 released from the tightening force is pulled toward the inner wall side of the housing 9 by the pulling force of the tension spring 8 to be divided. At the same time, the bolt 3 that is unscrewed from the separation nut 4 is also pushed out toward the structure 1 by the elastic force of the bolt pushing spring 9. As a result, the structures 1 and 2 are instantly separated.

The present invention is not limited to the above-described embodiments, but various modifications can be made within the scope of the invention, and include, for example, the following modifications. Although the separating nut has a two-divided structure in the above-described embodiment, it may be divided into three or more parts. Also, although the shape memory alloy coil is of the OneWay type, it may be of the TwoWay type. In this case, it is not necessary to plastically deform the shape memory alloy coil at the time of joining, and workability can be improved. The separation nut can also be formed by an elastic body. In this case, elastic force of the elastic body itself works, so that it is not necessary to provide a tension spring.

[0019]

As described above, according to the space structure separating mechanism of the present invention, it is possible to combine the structures in a lightweight and compact structure without the need for pyrotechnics and other complicated structures. ， The separation can be performed safely, surely and quickly.

[Brief description of drawings]

FIG. 1A is a cross-sectional view of an essential part showing a state when a space structure separating mechanism according to an embodiment is coupled, and FIG. 1B is a perspective view showing a state where a separating nut is integrated.

FIG. 2A is a sectional view of an essential part showing a state of separation of an embodiment of a space structure separation mechanism, and FIG. 2B is a perspective view showing a state where a separation nut is separated.

3A and 3B are cross-sectional views of a main part showing a separation mechanism of a conventional space structure, in which FIG. 3A shows a state of connection and FIG. 3B shows a state of separation.

[Explanation of symbols]

 1 Structure 2 Structure 3 Bolt 4 Separation Nut 5 Housing 6 Shape Memory Alloy Coil 7 Heater 8 Tension Spring 9 Bolt Extrusion Spring 10 Screw 14 Conventional Separation Nut 15 Conventional Housing 16 Piston 17 Pyrotechnics

Claims (3)

[Claims] 1. A bolt for coupling a pair of structures, a housing provided on one of the pair of structures, a housing provided inside the housing, and divided in a radial direction to be screwed with the bolt. A separation nut, a shape memory alloy coil wound around the outer periphery of the separation nut in a coil shape, each end of which is connected to a heater through the housing, and a bolt provided between the tip of the bolt and the inner wall of the housing. A space structure separation mechanism comprising: a bolt pushing spring that presses against the structure side. 2. The separating mechanism for a space structure according to claim 1, wherein the separating nut has a structure in which the separating nut is divided into two in a radial direction at a center plane in the axial direction. 3. The space structure separating mechanism according to claim 1, wherein a spring for pulling the separating nut in a radial direction is provided between the side surface of the separating nut and the inner wall of the housing.