JP2011103713A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator having high strength, wherein it is possible to suppress driving voltage and obtain a displacement in the same direction as that of the natural movement of a muscle. <P>SOLUTION: The actuator includes: a first electrode 11 to which positive voltage is applied; a second electrode 12 to which negative voltage is applied; and a dielectric elastomer 13 sandwiched between the first electrode 11 and the second electrode 12. The actuator has a laminated structure in which the multiple first electrodes 11 and second electrodes 12 are alternately arranged with the dielectric elastomer 13 in between. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an actuator.

  In recent years, electric field-driven polymer soft actuators (artificial muscles) have been actively developed with the aim of imitating muscle tissue of a living body in engineering. This actuator has a structure in which a dielectric elastomer is sandwiched between two flexible electrodes (see, for example, Patent Document 1).

  The operating principle of this actuator will be described. When a voltage is applied to the dielectric elastomer, the electrodes attract each other due to the Coulomb force generated between the electrodes. Then, the dielectric elastomer is compressed in the vertical direction (film thickness direction) with respect to the electrode by elastic deformation, and is expanded in the horizontal direction (plane direction) with respect to the electrode. Of the two displacements in the film thickness direction and the plane direction, the compressive displacement in the film thickness direction is negligible, and therefore, when used as an actuator, the extension displacement in the plane direction is used.

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However, since the extension displacement in the planar direction is not a direction to contract in response to the electrical stimulation, the extension displacement is in a direction opposite to the natural muscle movement direction. In addition, there is a method of increasing the thickness of the dielectric elastomer in order to obtain a displacement amount in the same direction as the natural muscle movement direction, but if the drive voltage is V and the thickness of the dielectric elastomer is d, the absolute value of the displacement amount. Is proportional to V ³ / d ² , which requires a very high drive voltage and is not practical. In addition, the drive voltage can be lowered by making the dielectric elastomer thin, but the strength of the actuator may be reduced.

  The present invention has been made in view of such circumstances, and provides a high-strength actuator capable of obtaining a displacement amount in the same direction as the natural muscle movement direction while suppressing a drive voltage. Objective.

In order to solve the above problems, the actuator of the present invention includes a first electrode to which a positive voltage is applied, a second electrode to which a negative voltage is applied, the first electrode, and the second electrode. A dielectric elastomer sandwiched between the electrodes, and having a laminated structure in which a plurality of the first electrodes and the second electrodes are alternately arranged via the dielectric elastomer. .

According to the actuator of the present invention, when a voltage is applied between the electrodes (between the first electrode and the second electrode), each dielectric elastomer is elastically deformed to be perpendicular to the electrodes (thickness direction). ) In the horizontal direction (plane direction) with respect to the electrode. That is, the amount of compressive displacement of the entire actuator is the sum of the amount of compressive displacement of each electrode and the amount of compressive displacement of each dielectric elastomer. For this reason, if the drive voltage (applied voltage) is V and the film thickness of the dielectric elastomer is d, the absolute value of the displacement is proportional to V ³ / d ² , so that compared with a case where the film thickness of the dielectric elastomer is simply increased. By using a laminated structure, the amount of displacement in the film thickness direction can be increased for the same drive voltage. Therefore, it is possible to provide a high-strength actuator capable of obtaining a displacement amount in the same direction as the natural muscle movement direction while suppressing the drive voltage.

In the actuator, the first electrode and the second electrode may have elasticity.
According to this configuration, each electrode can flexibly deform (compress, elongate) following the elastic deformation of each dielectric elastomer. Therefore, it is possible to easily obtain a displacement amount in the same direction as the natural muscle movement direction while suppressing the drive voltage.

In this actuator, the first electrode and the second electrode may be connected to a first wiring and a second wiring having elasticity, respectively.
According to this configuration, each electrode can be deformed flexibly without being inhibited from being deformed by each wiring. Therefore, it is possible to easily obtain a displacement amount in the same direction as the natural muscle movement direction while suppressing the drive voltage.

In the actuator, the first wiring and the second wiring may be formed of the same material as the first electrode and the second electrode, respectively.
According to this configuration, since the connectivity between each electrode and each wiring is improved, this connecting portion can flexibly deform following the elastic deformation of each dielectric elastomer. Therefore, it is possible to easily obtain a displacement amount in the same direction as the natural muscle movement direction while suppressing the drive voltage.

It is a schematic diagram which shows schematic structure of the actuator of this invention. It is a figure which shows the state after the voltage application of an actuator. It is a figure which shows an example of the preparation methods of an actuator.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

  FIG. 1 is a schematic diagram showing a schematic configuration of an actuator 1 of the present invention. In the present embodiment, an electric field driven polymer soft actuator (artificial muscle) will be described as an example of the actuator 1. As shown in FIG. 1, the actuator 1 includes a first electrode 11, a second electrode 12, a dielectric elastomer 13, a first wiring 21, and a second wiring 22. ing.

  The first electrode 11 is an electrode to which a positive voltage is applied. The first electrode 11 has elasticity so as to follow the elastic deformation of the dielectric elastomer 13 and extend in the same manner as the dielectric elastomer 13. That is, the first electrode 11 extends in the plane direction in the same manner as the dielectric elastomer 13 before and after voltage application. The film thickness of the first electrode 11 is preferably set in the range of 0.01 to 0.5 μm, for example.

  As a material for forming the first electrode 11, for example, conductive grease, colloidal suspension, carbon black, metal such as gold or silver, or ionically or electronically conductive polymer can be used. Examples of the conductive grease include contact grease manufactured by Sanhayato Corporation. Examples of the carbon black include carbon black powder manufactured by Mitsubishi Chemical Corporation and ketjen black EC manufactured by Lion Corporation. In addition, when using carbon black or a metal, it is desirable to form in a thin film form or to mix with a gel or a polymer. Thereby, even when carbon black or a metal is used, the first electrode 11 has a certain degree of elasticity.

  The second electrode 12 is an electrode to which a negative voltage is applied. Similar to the first electrode 11, the second electrode 12 has elasticity. As the material for forming the second electrode 12, for example, conductive grease, colloidal suspension, carbon black, metal, and a conductive polymer can be used as in the first electrode 11 described above. The film thickness of the first electrode 11 is preferably set in the range of 0.01 to 0.5 μm, for example.

The dielectric elastomer 13 is sandwiched between the first electrode 11 and the second electrode 12. When a voltage is applied between the first electrode 11 and the second electrode 12, the dielectric elastomer 13 is compressed in a direction perpendicular to the electrode (film thickness direction) by elastic deformation, and Extends horizontally (plane direction). At this time, the stress σ generated between the electrodes sandwiching the dielectric elastomer is expressed by the formula σ = ε ₀ εE ² and is proportional to the square of the electric field strength. Here, ε ₀ is the dielectric constant of vacuum, ε is the relative dielectric constant, and E is the electric field strength. The film thickness of the dielectric elastomer 13 is preferably set in the range of 0.01 to 0.5 mm, for example.

  As a material for forming the dielectric elastomer 13, an insulating polymer or rubber can be used. As the polymer, for example, a silicone elastomer, an acrylic elastomer, a thermoplastic elastomer, a copolymer containing polyvinylidene fluoride (PVDF), a fluoroelastomer, a polymer containing a silicone component and an acrylic component can be used. For example, silicone rubber, acrylic rubber, or urethane rubber can be used as the rubber. Examples of the silicone rubber include SE9188 manufactured by Toray Dow Corning Co., Ltd. Examples of the acrylic rubber include N915 manufactured by Amon Industry Co., Ltd. Examples of the urethane rubber include a hypergel sheet manufactured by Exeal Corporation.

  The first wiring 21 has one main wiring portion 21a connected to a power source and a sub wiring portion 21b branched from the main wiring portion 21a. Each sub wiring part 21 b is connected to each first electrode 11. As a material for forming the first wiring 21, for example, conductive grease, colloidal suspension, carbon black, metal, and a conductive polymer can be used as in the first electrode 11 described above. In addition, the first wiring 21 has elasticity as in the first electrode 11 described above.

  The second wiring 22 has one main wiring portion 22a connected to the power source and a sub wiring portion 22b branched from the main wiring portion 22a. Each sub wiring part 22b is connected to each second electrode 12 respectively. As the material for forming the second wiring 22, for example, conductive grease, colloidal suspension, carbon black, metal, or a conductive polymer can be used, as in the case of the second electrode 12 described above. In addition, the second wiring 22 has elasticity as in the second electrode 12 described above.

  The actuator 1 has a laminated structure in which a plurality of first electrodes 11 and second electrodes 12 are alternately arranged via a dielectric elastomer 13. Specifically, the first electrode 11, the dielectric elastomer 13, the second electrode 12, the dielectric elastomer 13, the first electrode 11, the dielectric elastomer 13, and the second electrode 12 are stacked in series in this order. ing. Thereby, the thickness of the actuator 1 in the stacking direction is, for example, in the range of 0.1 to 5 mm. The number of the first electrode 11, the dielectric elastomer 13, and the second electrode 12 to be stacked is not particularly limited, and can be appropriately set as necessary.

  FIG. 2 is a diagram illustrating a state before and after voltage application of the actuator 1. FIG. 2A shows a state before voltage application, and FIG. 2B shows a state after voltage application. In FIG. 2, illustration of wiring and a power source is omitted for convenience.

As shown in FIG. 2, the actuator 1 has a cylindrical shape in which a plurality of first electrodes 11 and second electrodes 12 are alternately arranged via a dielectric elastomer 13. When a voltage is applied between each electrode (between the first electrode 11 and the second electrode 12), each dielectric elastomer 13 is compressed in a direction perpendicular to the electrode (film thickness direction) by elastic deformation, It extends in the horizontal direction (plane direction) with respect to the electrode. That is, the total amount of compressive displacement of the actuator 1 is the sum of the amount of compressive displacement of each electrode and the amount of compressive displacement of each dielectric elastomer. For this reason, if the drive voltage (applied voltage) is V and the film thickness of the dielectric elastomer is d, the absolute value of the displacement is proportional to V ³ / d ² , so that compared with a case where the film thickness of the dielectric elastomer is simply increased. By using a laminated structure, the amount of displacement in the film thickness direction can be increased for the same drive voltage. Further, even when the thickness of each dielectric elastomer is reduced in order to reduce the drive voltage, the strength of the actuator can be increased by using a laminated structure.

  The shape of the actuator 1 is not limited to a cylindrical shape. For example, any shape may be used as long as a plurality of first electrodes and second electrodes are alternately arranged via a dielectric elastomer, such as a cubic shape.

(Actuator production method)
Next, an example is given and demonstrated about the manufacturing method of the actuator 1 of this invention.
FIG. 3 is a diagram illustrating an example of a method for manufacturing the actuator 1. First, a film-like dielectric elastomer 13 is prepared. Next, the first electrode 11 is formed on the upper surface of the dielectric elastomer 13 by using, for example, a spin coating method. Similarly, the second electrode 12 is formed on the upper surface of the dielectric elastomer 13 by using, for example, a spin coat method. Next, an insulating mask (first mask 14) is formed on one end face of the first electrode 11 on the dielectric elastomer 13. Similarly, an insulating mask (second mask 15) is formed on one end surface of the second electrode 12 on the dielectric elastomer 13 (on the side opposite to the side on which the first mask 14 is formed). The insulating masks 14 and 15 may be formed on the upper surfaces of the electrodes as long as they are formed on at least the end surfaces of the electrodes.

  Next, the dielectric elastomer 13 on which the first electrode 11 is formed and the dielectric elastomer 13 on which the second electrode 12 is formed are laminated and laminated. At this time, it arrange | positions so that the 1st mask 14 formed in the end surface of the 1st electrode 11 and the 2nd mask 15 formed in the end surface of the 2nd electrode 12 may not adjoin. Next, the other end surface of the first electrode 11 (the side where the first mask 14 is not formed) and the one end surface of the second electrode 12 (the side where the second mask 15 is formed). A first wiring 21 is formed. At this time, since the second mask 15 is formed on one end surface of the second electrode 12, the second electrode 12 and the first wiring 21 can be electrically connected via the first wiring 21. Absent. That is, the first wiring 21 is selectively conducted with the first electrode 11. Similarly, the other end surface of the second electrode 12 (the side where the first mask 15 is not formed) and the one end surface of the first electrode 11 (the side where the first mask 14 is formed). ) To form the second wiring 22. Through the above steps, the actuator 1 of the present invention is manufactured.

According to the actuator 1 of the present invention, when a voltage is applied between the electrodes (between the first electrode 11 and the second electrode 12), each dielectric elastomer 13 is perpendicular to the electrodes by elastic deformation. Compress in the film thickness direction and extend in the horizontal direction (plane direction) with respect to the electrode. That is, the total amount of compressive displacement of the actuator 1 is the sum of the amount of compressive displacement of each electrode and the amount of compressive displacement of each dielectric elastomer. For this reason, if the drive voltage (applied voltage) is V and the film thickness of the dielectric elastomer is d, the absolute value of the displacement is proportional to V ³ / d ² , so that compared with a case where the film thickness of the dielectric elastomer is simply increased. By using a laminated structure, the amount of displacement in the film thickness direction can be increased for the same drive voltage. Therefore, it is possible to provide a high-strength actuator 1 that can obtain a displacement amount in the same direction as the natural muscle movement direction while suppressing the drive voltage.

  Further, according to this configuration, since the first electrode 11 and the second electrode 12 have elasticity, each electrode 11, 12 flexibly deforms following the elastic deformation of each dielectric elastomer 13 ( Compression, decompression).

  In addition, according to this configuration, the first electrode 11 and the second electrode 12 are connected to the first wiring 21 and the second wiring 22 having elasticity, respectively. However, the wirings 21 and 22 can be deformed flexibly without being inhibited from being deformed.

  In addition, according to this configuration, the first wiring 21 and the second wiring 22 are formed of the same material as the first electrode 11 and the second electrode 12, respectively. Since the connectivity between 21 and 22 is improved, this connecting portion can flexibly deform following the elastic deformation of each dielectric elastomer 13. Therefore, it is possible to easily obtain a displacement amount in the same direction as the natural muscle movement direction while suppressing the drive voltage.

  The actuator of the present invention can also be applied to a soft actuator used for a powered suit, for example. According to the actuator of the present invention, a displacement amount in two directions, that is, a displacement amount in the film thickness direction (compression displacement amount) and a displacement amount in the plane direction (elongation displacement amount) can be obtained. For this reason, it is possible to provide a soft actuator that is more compact than a structure in which a structure capable of obtaining a compression displacement amount and a structure capable of obtaining an extension displacement amount are combined.

DESCRIPTION OF SYMBOLS 1 ... Actuator, 11 ... 1st electrode, 12 ... 2nd electrode, 13 ... Dielectric elastomer, 21 ... 1st wiring, 22 ... 2nd wiring

Claims (4)

A first electrode to which a positive voltage is applied;
A second electrode to which a negative voltage is applied;
A dielectric elastomer sandwiched between the first electrode and the second electrode,
An actuator having a laminated structure in which a plurality of the first electrodes and the second electrodes are alternately arranged via the dielectric elastomer.   The actuator according to claim 1, wherein the first electrode and the second electrode have elasticity.   3. The actuator according to claim 1, wherein a first wiring and a second wiring having elasticity are connected to the first electrode and the second electrode, respectively.   4. The actuator according to claim 3, wherein the first wiring and the second wiring are made of the same material as the first electrode and the second electrode, respectively.

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