JP6590218B2 - Bistable boom - Google Patents

Description

  The present invention relates to a boom used for structural materials of various structures such as space structures and ground structures such as satellites and spacecraft antennas and solar battery panels, and in particular, a wound state and an extended state. It is related with the bistable boom which can hold | maintain stably.

As this type of conventional bistable boom, for example, a stretchable member as described in Patent Document 1 is known.
In other words, the boom body is formed of a long plate material having elasticity, and is bent into an open cross-sectional shape in a direction perpendicular to the longitudinal direction (hereinafter referred to as a short direction), while being wound in a cylindrical shape in the longitudinal direction. It is configured to be bent in the taken-up winding form and stably held in either the extended form or the rolled-up form in the initial form.
In the winding form, the boom body has an open cross-sectional shape in the short direction that extends linearly, and is held by a cylindrical rigidity that is wound with an elastic restoring force to return to the open cross-sectional direction. .
When the boom body that is stable in the winding form is a partially extended form, the winding form section is a straight line from the boundary part of the extending form, and the cross-sectional shape in the short direction of the boom body is linearly changed in sequence by the elastic restoring force. It returns to the open cross-sectional shape from the state, shifts from the winding form to the extended form, and self-extends.

Special Table 2000-507890

However, when winding from the extended configuration to the winding configuration, or during self-extending from the winding configuration, a tear may occur at the side edge of the boom body.
In the winding form, the boom main body is linearly extended along the cylindrical generatrix in the short direction, so that bending stress in the direction to return to the open cross-sectional shape acts, and the winding form When transitioning from a stretched form to a stretched form, the boundary where the rigid cylindrical winding form transitions to the stretched form, in particular, the stress concentrates at both ends in the short-side direction and is bent, resulting in a tear from the bent part. It is done. In particular, when molding is made of fiber reinforced plastic (FRP) using a fiber base material as a material for the boom body, a tear is likely to occur along the orientation direction of the base fiber.
Therefore, it is conceivable to increase the strength of the boom body, but the bending stress generated in the boom body in the winding form also increases. In addition, the force required for winding is increased, which hinders the winding operation. Furthermore, the self-extending force increases, and the impacting force is applied to the member that supports the boom main body.
The present invention has been made in view of such a situation, and an object of the present invention is to prevent a tear generated at the side edge of the boom body and to smoothly advance the transition between the wound state and the extended state. It is to provide a bistable boom that can.

In order to achieve the above object, the present invention is constituted by a long resin plate material having elasticity, and is bent in an open cross-sectional shape in a direction perpendicular to the longitudinal direction, while in the longitudinal direction. a song with form the take-Rikatachi state wound up in a cylindrical shape, in the initial state, a stable bistability is held either in the form of extended form and winding form extending in the longitudinal direction In the bistable boom with the boom body of
The side edge portion extending along the longitudinal direction of the boom body is coated with a reinforcing material having a soft resin material having rubber-like elasticity, and the reinforcing material is laminated on the surface of the soft resin material with low friction characteristics. It is characterized by having a laminated structure provided with the resin material .
In the vicinity of the boundary of the transition region from the winding state of the boom body to the extended state, the bending stress in the short direction in the winding state is released all at once, but the impact is mitigated by the reinforcing material, and the generation of a tear is prevented. .
Further, since only the side edge portion is covered, the transition of the boom body to the winding state and the extended state proceeds smoothly.

As a resin material having low friction characteristics, a material having both low friction characteristics, flexibility, and difficulty in peeling, for example, a thin film PTFE adhesive tape can be used.
By providing a resin material having low friction characteristics, the transition between the wound state and the extended state proceeds more smoothly.
A urethane resin can be used as the soft resin material, and a fluorine resin can be used as the resin material having low friction characteristics.
The boom body is preferably made of a fiber reinforced resin obtained by impregnating a fiber base material with a resin.
As the fiber substrate, a braided structure or a biaxial woven structure can be used.
As the biaxial fabric structure, the first axis yarn and the second axis yarn can be inclined at a predetermined angle in opposite directions with respect to the long axis along one longitudinal direction.
The yarn constituting the biaxial woven fabric can be a spread yarn.
Further, the boom body can have a laminated structure in which a plurality of fiber reinforced resin sheets obtained by impregnating a fiber base material of a biaxial woven fabric with resin are laminated.
Moreover, about the thread | yarn which comprises a fiber base material, it can be set as carbon fiber.
In the bistable boom of the present invention, by pulling out the tip of the boom body in the wound state to the extended state, the pulled-out portion shifts from the wound state to the extended state, and in the transition portion from the wound state to the pulled-out portion A self-extending boom that self-extends from a wound state to an extended state can be obtained by an elastic restoring force that elastically returns the cross-sectional shape to an open cross-sectional shape.
Moreover, it can also be set as the bistable boom which stops stably in the middle of the transition of a winding state and an extension state.

  According to the bistable boom of this invention, the crack which arises in the side edge part of a boom main body can be prevented, and the transition with a winding state and an extended state can be advanced smoothly.

FIG. 1 shows an example of a bistable boom according to an embodiment of the present invention, in which (A) is a perspective view of a partially extended state, (B) is a perspective view of a winding form, and (C) is an extended state. It is a perspective view of a form. (A) is sectional drawing of the short direction of a boom main body, (B) is an expanded sectional view of the part of a reinforcing material, (C) is a conceptual diagram of the motor drive of a balance type bistable boom. FIG. 1 shows an FRP sheet constituting the boom body of FIG. 1, (A) is an explanatory view of the orientation direction of the yarn of the fiber base material, (B) is a perspective view showing a plurality of FRP sheets to be stacked, (C) FIG. 3 is a schematic sectional view of a laminated structure. It is a figure which shows the example of another structure | tissue structure of the fiber base material of the FRP sheet | seat of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Embodiment 1]
FIG. 1 is a diagram showing a bistable boom according to Embodiment 1 of the present invention.
That is, the bistable boom 1 has a boom body 10 made of a long elastic resin plate material, and the boom body 10 is bent into an open cross-sectional shape in a direction perpendicular to the longitudinal direction. On the other hand, in the longitudinal direction, it is bent into a winding form wound in a cylindrical shape in the longitudinal direction. It has bistability that is stably held in any form of the take-up form.
In the following description, the winding form part of the boom main body 10 will be described with reference numeral 10A, and the extension form part will be described with reference numeral 10B.
Assuming that the bistable boom 1 is partially extended, the winding form portion 10A has a cross-sectional shape in the short direction of the boom body 10 from the boundary portion of the extended form, and the elastic restoring force sequentially changes the linear shape from the linear state. Returning to the open cross-sectional shape, the winding shape is changed to the extended shape, and the extended shape is extended.

That is, as shown in FIG. 1 (A), there is a transition area 10C that transitions from the winding form part 10A to the extended form part 10B, and from the boundary position 10D that transitions to the extended form part 10B and the transition area 10C, the boom body The cross-sectional shape in the short-side direction of 10 gradually returns from the linear state to the open cross-sectional shape by the elastic restoring force, shifts from the winding form portion 10A to the extending form portion 10B, and self-extends.
In this invention, it becomes the structure which covered the reinforcing material 30 provided with the soft resin material which has rubber-like elasticity in the both-sides edge part extended along the longitudinal direction of the boom main body 10 of an open cross-section shape, covering the full length. Yes.

Configuration of the Boom Body The boom body 10 has an open cross-sectional shape in the short direction that is a circular arc shape that forms a part of a circle, and an opening angle α formed by a line connecting both ends of the arc and the center of curvature is 160 °. Set to degree. When this opening angle is large, the elastic restoring force when the open cross-sectional shape is deformed linearly is small, and when it is large, the elastic restoring force is large. If it is too large, the elastic restoring force becomes excessive and cannot be wound, so it is set to about 40 ° to 180 °.
In this example, the cross-sectional shape in the short direction of the boom body 10 is an arc shape forming a part of a perfect circle, but it is not necessary to be a part of a perfect circle, and may be a part of an ellipse. It may have a curved shape with a non-circular cross section that is partially open.

As shown in FIG. 3, the boom body 10 has a laminated structure in which a plurality of fiber reinforced resin sheets (FRP sheets) 13 are laminated. Each fiber reinforced resin sheet 13 has the same configuration, and the fiber base material 11 is impregnated with the matrix resin 12.
The fiber base material 11 has a biaxial woven fabric structure, and the first axial thread 11a and the second axial thread 11b have a predetermined angle θ (orientation angle) in directions opposite to each other with respect to the long axis N1 along one longitudinal direction. It has a configuration that only tilts. The orientation angle is 45 °.
In this embodiment, the first axial yarn 11a and the second axial yarn 11b are made of carbon fibers, and are particularly constituted by spread yarns in which the fiber bundles are flatly bundled, and the thickness of the single fiber-reinforced resin sheet 13 Is set thin, and a plurality of fiber reinforced resin sheets 13 are bonded together to form the boom body 10. In this example, it is preferable that the fiber reinforced resin sheet 13 has a two-layer to four-layer structure. However, by increasing the number of layers, the stretching force is increased stepwise.
Although it depends on the sheet thickness, the cross-sectional shape of the boom body 10 and the elastic modulus, for example, in the case of two layers (2 ply), even if the leading end is pulled out from the wound state, the self-extension force is weak and it returns to the fully extended state. Absent.
In the three layers (3ply), the self-stretching force is strong and stress relaxation occurs over time, but self-stretching that returns from the wound state to the completely stretched state appears in the short term.
In the 4 layers (4ply), the self-stretching force is too strong, and a considerable force is required for winding.

In order to make it self-extend, it is preferable to have a three-layer structure. However, a structure in which the self-extension force is weak and the extension does not partition is also useful. That is, for the form that balances and stabilizes in the state in which the winding form and the extending form are held, the force in the extending direction and the winding direction is maintained in a balanced state. For example, as shown in FIG. If the motor 100 is wound up and extended, the required torque can be reduced and can be expanded and contracted as necessary.
In the case of the structure of self-extension, no power is required for extension, but if winding is performed by a motor, a large torque is required.
In addition, although it described about the number of lamination | stacking of the above-mentioned fiber reinforced resin sheet 13 as a structure where 3 layers self-extend, 2 layers are the structure where a winding form and an extending form balance, 4 layers are the structures where winding is difficult. Depending on the conditions, such as the opening angle of the boom body, the plate thickness, and the elastic modulus of the material, the number of layers of the self-extending type and the balance type sheet that balances the winding form and the extending form is one layer. It can be selected as appropriate.

Structure of Reinforcing Material Reinforcing material 30 is, as shown in enlarged view in FIGS. 2A and 2B, a main body portion 31 made of a soft resin having rubber-like elasticity and a low friction characteristic covering the surface of main body portion 31. And a surface layer 32 made of a resin material having a laminated structure.
The main body 31 has a U-shaped cross section in which a groove 31a into which the side edge of the boom body 10 is inserted, and is bonded to the inner piece 31b bonded to the inner surface of the side edge of the boom body 10 and the outer surface. An outer piece 31c, and a connecting portion 31d that connects the inner piece and the outer piece and is bonded to the end face of the side edge portion.
As the soft resin constituting the main body 31, an elastomer such as a thermoplastic polyurethane resin (TPU) is suitable. TPU is excellent in flexibility and adhesiveness, and has an effect of increasing the tear strength of the bistable boom terminal portion and preventing the fiber reinforced resin CFRP from cracking in the fiber orientation direction. The physical property value of TPU is preferably a polyester or polyether TPU (thermoplastic polyurethane resin) having a hardness (JIS A) of 90 or more and a tensile elongation of 500% or more according to a test method based on JIS K7311. For example, polyurethane elastomer film (product number: DUS 202, DUS213, DUS501, DUS601, DUS605, DUS220, DUS451, etc., manufactured by Seadam Co., Ltd. can be used. ) Is 90, the tensile depth is 520%, the tensile strength is 80 (MPa), and the tensile strength is 9 (N).
Since TPU is excellent in flexibility, it can suppress adverse effects on storage and extension characteristics of the bistable boom. However, since there is tackiness, slippage may be worsened when TPUs come into contact with each other. Therefore, in order to improve sliding, the surface layer 32 made of a resin material having a low friction characteristic is covered.
The surface layer 32 is made of a resin material having low friction and wear resistance, for example, tetrafluoroethylene resin (PTFE). In particular, a material having flexibility and difficulty in peeling in addition to low friction properties is preferable. For example, a thin film PTFE adhesive tape (product number: ASF-116T) manufactured by Chuko Kasei Kogyo Co., Ltd. can be used. This tape has a total thickness of 43 μm (PTFE base material thickness 21 μm, adhesive material thickness 22 μm). By covering the main body 31 with the low-friction surface layer 32 in this way, there is an effect that the friction resistance of the bistable boom terminal portion is reduced and the storage and extension are smooth. Moreover, since it is a thin film, it has the property of suppressing mass increase and being difficult to peel off.
Of course, the material of the surface layer 32 is not limited to tetrafluoroethylene resin, and any material having both low friction characteristics, flexibility, and difficulty in peeling off may be used.

Next, the effect | action of the reinforcement material of the bidirectional | two-way stable boom of this embodiment is demonstrated.
In the vicinity of the boundary of the transition region from the winding state of the boom body 10 to the extended state, the bending stress in the short direction in the winding state is released, and a large shearing force acts near the boundary. The rubber-like elasticity of 31 disperses and relaxes the shearing force and prevents the generation of tears. In particular, when the boom body 10 has a laminated structure of fiber reinforced resin sheets 13, if the phases of the yarns of the fiber base material 11 of each sheet are overlapped, a tear is likely to occur along the overlapped yarns. By covering with, it is possible to prevent tears.
Furthermore, since the surface of the reinforcing material 30 is covered with the low-friction surface layer 32, even if the reinforcing materials 30 come into contact with each other during winding, the contact surface slips and smoothly takes up the winding form and the extending form. The transition proceeds.
In addition, since the reinforcing material 30 only covers the side edge portion, resistance to deformation due to winding and extension is small, and the transition from the winding form to the extended state is coupled with the smoothness of the surface of the reinforcing material 30. Proceed smoothly.

Other Embodiments In the above-described embodiment, a plain woven fabric structure is used as the fiber reinforced resin constituting the boom body 10, but a braided structure as shown in FIG. 4 can also be used.
The illustrated example is a fiber base 51 having a round structure, and has a bias configuration in which a large number of braids 51a and 51a intersecting each other in the opposite directions with respect to the vertical axis are alternately entangled. There may be warps. If the braid structure is used, the orientation angle of the braid can be arbitrarily set.
About this orientation angle, it is known that the winding storage property is good as the orientation angle increases, and the storage state becomes unstable as the orientation angle decreases, and the fiber orientation angle ranges from about 30 ° to 60 °, It is particularly preferable to set the angle around 60 °. In the case of a braided structure, it is not a spread fiber and is not a multi-layer structure, but it may be a multi-layer structure as in the above embodiment.
The tear tends to occur when the fiber orientation angle is large, but the optimum orientation angle can be selected by providing the reinforcing material 30 as in the present invention.

In addition, as a structure | tissue of a fiber base material, it is not limited to the above-mentioned textile fabric and braid structure | tissue, It is possible to utilize various base materials, such as a knitted structure, a net | network structure, and a nonwoven fabric.
In addition, the bistable extension structure of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Bistability boom 10 Boom main body 10A Winding form part 10B Extension form part 10C Transition area | region 10D Boundary position 11 Fiber base material 11a: 1st axial thread, 11b 2nd axial thread 12 Matrix resin 13 Fiber reinforced resin sheet 30 Reinforcement material 31 body part 31a groove part, 31b inner piece, 31c outer piece, 31d connecting part 32: surface layer

Claims (11)

Is constituted by a resin plate elongated having elasticity, in the form in the direction that is the song with the open cross-sectional shape perpendicular to the longitudinal direction, on the other hand, in the longitudinal direction the winding is wound in a cylindrical shape Rikatachi In a bistable boom having a bistable boom body that is stably held in an extended form and a take-up form extending in the longitudinal direction in an initial state in a bent form,
The side edge portion extending along the longitudinal direction of the boom body is coated with a reinforcing material having a soft resin material having rubber-like elasticity, and the reinforcing material is laminated on the surface of the soft resin material with low friction characteristics. A bistable boom characterized by having a laminated structure including a resin material . The bistable boom according to claim 1 , wherein the soft resin material is a urethane resin. The bistable boom according to claim 1 , wherein the resin material having low friction characteristics is a fluororesin. The bistable boom according to any one of claims 1 to 3 , wherein the boom body is made of a fiber reinforced resin in which a fiber base material is impregnated with a resin. The bistable boom of claim 4 , wherein the fiber substrate is a braided tissue. The fiber base material has a biaxial woven structure, and the first axis yarn and the second axis yarn are inclined at a predetermined angle in directions opposite to each other with respect to a long axis along one longitudinal direction. The bistable boom of claim 4 . The bistable boom according to claim 6 , wherein the yarn constituting the fiber base material is a spread yarn. The bistable boom according to claim 6 or 7 , wherein the boom body has a laminated structure in which a plurality of fiber reinforced resin sheets obtained by impregnating a fiber base material with a resin are laminated. The bistable boom according to any one of claims 4 to 8 , wherein the yarn constituting the fiber base material is carbon fiber. When the boom body that is stable in the winding form is a partially extended form, the winding form section is a straight line from the boundary part of the extending form, and the cross-sectional shape in the short direction of the boom body is linearly changed in sequence by the elastic restoring force. The bistable boom according to any one of claims 1 to 9 , wherein the bistable boom is a self-expanding boom that returns from the state to an open cross-sectional shape and shifts from a winding form to an extending form and self-extends. The bistable boom according to any one of claims 1 to 9 , wherein a form in which both the winding form part and the extending form part coexist is stably maintained.

Images