JP2010239784A - Actuator element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator element which expands and contracts upon voltage application, and improves the amount of expansion and contraction. <P>SOLUTION: The actuator element includes a spring-shaped structure having a coil-shaped spring which is formed by winding a linear member into a spiral shape and is capable of expansion and contraction, and a thin-film part with properties to expand and contract in response to application of a voltage. The thin-film part is fixed at the outer periphery of the linear member, and is spirally extended along an axis line of the linear member. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an actuator element, and more particularly to an actuator element that expands and contracts when a voltage is applied.

  In the fields of medical robots, welfare robots, industrial robots, micromachines, etc., there is an increasing need for actuator elements that are small, light, and flexible.

  In particular, polyacetylene is used as an actuator element that is driven at a low voltage, has quick response, is flexible, is easy to reduce in size and weight, has a large generated force per unit weight or unit volume, and operates with low power. Attention has been focused on actuator elements using conductive polymers such as polypyrrole, polyaniline and polythiophene (hereinafter referred to as “conductive polymer actuator elements”).

  These conductive polymers are known to develop a phenomenon that expands or deforms by electrochemical oxidation-reduction, so-called electrolytic expansion and contraction. Is configured to function as an actuator.

  Such a conductive polymer actuator element is disclosed in Patent Document 1, for example. This actuator element has a structure composed of a conductive polymer and a conductive base having elasticity and conductivity realized by a coil-type metallic spring-like member or a metal mesh. The structure is formed by combining a conductive polymer and a conductive substrate so that a space between each wire constituting the conductive substrate is filled with the conductive polymer. With this configuration, a sufficient voltage can be applied to the entire structure, and the wire rod functions as a reinforcing material to improve the mechanical strength of the actuator element.

JP 2004-216868 A

  A film body formed of a conductive polymer that expands and contracts electrolytically has a large amount of displacement (hereinafter referred to as “stretching amount”) that expands and contracts depending on the magnitude of an applied voltage. It is as small as 1-2% of its own length. Therefore, a conventional actuator element using such a film body cannot perform a sufficient expansion / contraction operation, that is, a sufficient generated force cannot be obtained. For example, artificial muscles and joints of robot arms are practically used. There is a problem that it cannot be used as a drive source in typical applications.

  In Patent Document 1, in order to obtain a larger expansion / contraction amount, it is assumed that the size of the element itself is increased, and a problem that occurs when the size is increased is solved. That is, according to Patent Document 1, in order to obtain a larger expansion / contraction amount, the size of the element itself must be increased.

  An object of the present invention is to provide an actuator element that expands and contracts by application of a voltage and that can improve the amount of expansion and contraction.

The present invention is formed by winding a linear member in a spiral shape, and a coiled spring portion that can be expanded and contracted,
An actuator element comprising a spring-like structure having a thin film portion having a property of expanding and contracting when a voltage is applied,
The actuator element is characterized in that the thin film portion is provided fixed to the outer peripheral portion of the spring portion, and extends spirally along the axis of the spring portion.

  In the invention, it is preferable that the thin film portion is formed of a conductive polymer.

  In the present invention, the spring portion is provided with an electrode layer in a spiral shape along the axis of the spring portion, and the thin film portion is provided on the electrode layer in a spiral shape.

  According to the present invention, the expansion / contraction amount in the spiral direction of the thin film portion extending in a spiral shape can be converted into the expansion / contraction amount of the spring-like structure in the axial direction of the spring portion. And by such conversion of the amount of expansion and contraction, the spring-like structure can be expanded and contracted with a larger amount of expansion and contraction than the amount of expansion and contraction that the thin film portion expands and contracts.

It is sectional drawing which shows schematically the structure of the actuator apparatus 100 provided with the actuator element 1 which concerns on the 1st Embodiment of this invention. It is a top view of the actuator apparatus 100 shown to FIG. 1A. It is sectional drawing seen from the cut surface line II in FIG. 1A. 2 is a perspective view schematically showing a part of the configuration of a spring-like structure 11 provided in the actuator element 1. FIG. It is a figure for demonstrating the spring-like structure 11a which comprises the actuator element 1a which concerns on 2nd Embodiment, Fig.3 (a) is a perspective view which expands and shows a part of spring-like structure 11a. FIG. 3 (b) is a cross-sectional view taken along section line III-III in FIG. 3 (a). It is a figure for demonstrating the actuator element 1b which concerns on 3rd Embodiment, Fig.4 (a) is a perspective view which expands and shows a part of spring-like structure 11a, FIG.4 (b) is FIG. FIG. 5 is a cross-sectional view taken along section line IV-IV in FIG. It is a perspective view showing roughly the composition of actuator device 100c concerning a 4th embodiment.

  FIG. 1A is a cross-sectional view schematically showing a configuration of an actuator device 100 including the actuator element 1 according to the first embodiment of the present invention. FIG. 1B is a plan view of the actuator device 100 shown in FIG. 1A. FIG. 1C is a cross-sectional view taken along section line II in FIG. 1A.

  The actuator device 100 includes an actuator element 1 having a spring-like structure 11 that expands and contracts by applying a voltage, a movable portion 2, a housing 3, a bottom plate 4, sealing materials 5a, 5b, and 5c, and a guide. And a member 6. The actuator device 100 is configured such that the movable portion 2 linearly reciprocates along the axial direction P of the housing 3 by expanding and contracting the spring-like structure 11. That is, the actuator device 100 is configured so that the force generated in the actuator element 1 can be transmitted to the outside of the actuator device 100 by reciprocating the movable portion 2 linearly.

  The actuator element 1 includes a spring-like structure 11 formed in the shape of a cylindrical coil spring, an electrolyte solution 12, a working electrode 13, a counter electrode 14, and a power source 15 that applies a voltage to the working electrode 13 and the counter electrode 14. With. Details of the actuator element 1 will be described later.

  The movable part 2 is a component that is integrally formed, and includes a circular plate-like disk part 2a and a right cylindrical column part 2b. The disc portion 2a is provided at one end of the shaft portion 2b so that the center axis of the disc portion 2a matches the center axis of the shaft portion 2b. Moreover, the disc part 2a has an outer diameter larger than the outer diameter of the axial part 2b, and has an outer diameter smaller than the outer diameter of the right cylindrical internal space S mentioned later.

  The housing | casing 3 is a component integrally formed in the right cylinder shape, and has the spring accommodating part 3a and the axial part guide part 3b. The housing | casing 3 is comprised by the member which has electrical insulation. The spring accommodating portion 3 a and the shaft guide portion 3 b have different inner diameters, and accordingly, a step is formed in the axial direction P on the inner wall surface portion of the housing 3.

  The spring accommodating portion 3a has an inner diameter larger than the inner diameter of the shaft portion guide portion 3b, and is sufficiently longer than the length of the spring-like structure 11 in the expanded state in the expansion / contraction direction (that is, the axis J2 direction described later). Now, it extends along the axial direction P of the housing 3. The spring accommodating portion 3a accommodates the spring-like structure 11 and the disc portion 2a of the movable portion 2. A cylindrical counter electrode 14 to be described later is provided along the inner wall surface on the inner wall surface portion of the spring accommodating portion 3a.

  The shaft portion guide portion 3b has an inner diameter slightly larger than the outer diameter of the shaft portion 2b of the movable portion 2, and extends along the axial direction P with a length shorter than the length in the longitudinal direction of the shaft portion 2b. Yes. A sealing material 5a and a guide member 6 to be described later are attached to the inner wall surface of the shaft guide portion 3b.

  The bottom plate 4 is formed of a circular plate-like member and has an outer diameter that is the same as or substantially the same as the outer diameter of the housing 3. The bottom plate 4 is configured by a member having electrical insulation. The bottom plate 4 is attached to the housing 3 so as to close the open end of the spring accommodating portion 3 a in the housing 3. When attaching to the housing 3, a sealing material 5 b described later is provided between the spring accommodating portion 3 a and the bottom plate 4.

  Further, the bottom plate 4 is formed with a through hole penetrating along the central axis of the bottom plate 4 from one surface to the other surface. A sealing material 5c, which will be described later, is attached to the wall surface part that defines the through hole, and a working electrode 13, which will be described later, is inserted into the through hole.

  By attaching the bottom plate 4 to the housing 3, an internal space S is formed inside the housing 3. That is, the internal space S is a space surrounded by the counter electrode 14 provided on the inner wall surface portion of the spring accommodating portion 3 a, the step surface portion formed in the housing 3, and one surface portion of the bottom plate 4. The internal space S is a sealed space, and the internal space S is filled with an electrolyte solution 12 described later.

  The sealing materials 5a to 5c are ring-shaped members provided to prevent the electrolyte solution 12 filled in the internal space S from leaking from the internal space S to the outside. Sealing material 5a-5c is comprised by the member which has electrical insulation.

  The sealing material 5a is attached to the inner wall surface portion of the shaft portion guide portion 3b of the housing 3, and specifically, is fixed and attached to the vicinity of the end portion on the side adjacent to the spring accommodating portion 3a by a known adhesive means. . The shaft portion 2b of the movable portion 2 is inserted through the sealing material 5a. That is, in the sealing material 5a, the electrolyte solution 12 leaks from a gap formed between the shaft portion guide portion 3b of the housing 3 and the shaft portion 2b of the movable portion 2 inserted through the shaft portion guide portion 3b. Is preventing. The shaft portion 2b of the movable portion 2 inserted through the sealing material 5a slides relative to the sealing material 5a when linearly reciprocating along the axial direction P.

  The sealing material 5b is fixed and attached by a known bonding means so that no gap is formed between the opening end of the spring accommodating portion 3a in the housing 3 and the bottom plate 4. That is, the sealing material 5 b prevents the electrolyte solution 12 from leaking from between the housing 3 and the bottom plate 4 attached to the housing 3.

  The sealing material 5c is fixed and attached to a wall surface part that defines a through hole formed in the bottom plate 4 by a known bonding means. A working electrode 13 described later is inserted through the sealing material 5c. That is, the sealing material 5c prevents the electrolyte solution 12 from leaking from the gap formed between the wall surface part defining the through hole of the bottom plate 4 and the working electrode 13 inserted through the through hole. .

  The guide member 6 is realized by, for example, a bearing, is provided on an inner wall surface portion of the shaft portion guide portion 3b of the housing 3, and the shaft portion 2b of the movable portion 2 is inserted therethrough. That is, the guide member 6 is a member that guides the shaft portion 2 b of the movable portion 2 that linearly reciprocates by the expansion and contraction of the spring-like structure 11.

Hereinafter, the actuator element 1 will be described in detail.
FIG. 2 is a perspective view schematically showing a part of the configuration of the spring-like structure 11 provided in the actuator element 1. The spring-like structure 11 includes a spring part 21 formed by the linear member 23 and a thin film part 22 having a property of expanding and contracting when a voltage is applied.

  The linear member 23 is a long member extending along the axis J1, and a cross section cut along a plane perpendicular to the axis J1 (hereinafter referred to as a “cross section”) has a circular shape, and is the same along the axis J1. Or it has the substantially same outer diameter.

  The spring portion 21 is formed by spirally winding such a linear member 23 around the axis J2. More specifically, the spring portion 21 has the same pitch angle (with respect to the axis J2 of the spiral trajectory of the linear member 23 spirally wound) except for the end winding portions at both ends. Angle).

  By forming the spring portion 21 in this way, the spring portion 21 can expand and contract in the direction of the axis J2. Specifically, the spring portion 21 contracts in the axis J2 direction when a compressive load is applied along the axis J2 direction. At this time, a torsional moment is generated along with the contraction in an arbitrary cross section of the linear member 23. When the compressive load is removed from the contracted state, the original state is restored by the elastic force. In addition, when a tensile load is applied along the direction of the axis J2, it extends in the direction of the axis J2. At this time, a torsional moment is generated along with expansion in an arbitrary cross section of the linear member 23. When the tensile load is removed from the stretched state, the original state is restored by the elastic force.

  The thin film portion 22 is provided fixed to the outer peripheral portion of the linear member 23 and extends spirally along the axis J <b> 1 of the linear member 23. Specifically, the thin film portion 22 is at least a portion of the spring portion 21 excluding the end winding portion, and has the same helical pitch, that is, the same pitch angle (that is, the axis of the spiral trajectory of the thin film portion 22 extending in a spiral shape). (An angle with respect to J1). Hereinafter, the pitch angle may be referred to as a lead angle. Moreover, let the direction where the thin film part 22 extends in the spring-shaped structure 11 be the spiral direction J3.

  In the spring-like structure 11 having such a configuration, one end winding portion is fixed to one surface portion of the bottom plate 4, and the other end winding portion is the disc portion 2 a of the movable portion 2. One surface part, that is, the disk part 2a is fixedly provided to the surface part opposite to the side where the shaft part 2b is provided. The spring-like structure 11 is arranged in the internal space S so that the axial direction J2 of the spring portion 21 and the axial direction P of the housing 3 coincide with each other.

  The working electrode 13 is formed by an electrically conductive metal so as to extend along the axis, and includes a connecting end that is an end on one side in the axial direction, a power-side end that is an end on the other side in the axial direction, And an insertion portion provided between the connection end and the power supply side end.

  The connecting end portion of the working electrode 13 is inserted into a through hole formed in one end portion of the linear member 23, that is, one end portion of the spring portion 21, and is connected to the spring portion 21. ing. A lead wire is connected to the end of the working electrode 13 on the power source side, and the working electrode 13 and the power source 15 are electrically connected via the lead wire.

  As described above, the working electrode 13 is fixed to the bottom plate 4 while being inserted into the sealing material 5c attached to the wall surface portion that defines the through-hole formed in the bottom plate 4. That is, the working electrode 13 has a connecting end located in the internal space S in the actuator device 100, and is inserted through the sealing material 5c at the insertion portion, and the power supply side end is exposed to the outside.

  As described above, the counter electrode 14 is formed in a cylindrical shape with a conductive metal, and is provided on the inner wall surface portion of the spring accommodating portion 3a by a known means such as vapor deposition. The spring accommodating portion 3a of the housing 3 has a minute through hole penetrating from the outer wall surface toward the inner wall surface, and the counter electrode 14 is exposed to the outside through the minute through hole. It has an exposed part. A lead wire is connected to the exposed portion, and the counter electrode 14 and the power source 15 are electrically connected via the lead wire.

  As described above, the power supply 15 is electrically connected to the working electrode 13 and the counter electrode 14 via the lead wires, and can apply a voltage to the working electrode 13 and the counter electrode 14.

  In the present embodiment, the linear member 23 is formed of a conductive conductor, and is preferably formed of a metal resistant to corrosion, such as titanium and stainless steel. The thin film portion 22 is formed of a known conductive polymer having a property of stretching or deforming by electrochemical oxidation and reduction, that is, electrolytic stretching, such as polyacetylene, polypyrrole, polyaniline, and polythiophene. Among these, polypyrrole is stable as a conductive polymer and can be suitably used.

  The thin film portion 22 may be fixed by adhering a conductive polymer film formed into a long film shape to the linear member 23 by a known bonding means (for example, using an adhesive). good. Moreover, you may form the thin film part 22 so that it may extend spirally along the spiral direction J3 on the outer peripheral surface of the linear member 23 by the electrolytic polymerization method.

  In the present embodiment, as described above, since the linear member 23 is formed of a conductive metal, the outer peripheral surface portion where the thin film portion 22 is not provided in the linear member 23 is covered with an insulating layer. It is preferable. This is because in the actuator device 100, the coil spring member 11 is provided in the internal space S filled with the electrolyte solution 12. That is, when the outer peripheral surface portion of the linear member 23 is exposed to the electrolyte solution 12, when a voltage is applied to the working electrode 13 and the counter electrode 14, ions move from the electrolyte solution 12 to the thin film portion 22. This is because the ion migration from the electrolyte solution 12 to the exposed outer peripheral surface portion is increased, and the doping of ions into the thin film portion 22 having higher conductivity than that of the metal is hindered. As a result, the electric field expansion and contraction of the thin film portion 22 is hindered, and in order to prevent this, the insulating layer is formed so that the portion where the thin film portion 22 is not provided is not exposed to the electrolyte solution 12 with respect to the outer peripheral surface portion. Is provided.

  In the present embodiment, as described above, the conductive polymer film formed in a long film shape is fixed to the outer peripheral surface of the linear member 23 along the spiral direction J3. Then, the conductive polymer is deposited by electrodeposition or adhesion on the entire surface so as to cover the outer peripheral surface portion of the linear member 23, and from above the conductive polymer layer covering the outer peripheral surface portion of the linear member 23, An insulating layer may be provided so that the conductive polymer layer is exposed to the electrolyte solution 12 in a spiral shape along the spiral direction J3. This can be realized by extending an insulating layer in parallel to the spiral direction J3 with respect to the conductive polymer layer covering the entire outer peripheral surface portion of the linear member 23. In this case, the portion of the conductive polymer layer covering the entire outer peripheral surface portion of the linear member 23 that extends in the spiral direction J3 so as to be exposed to the electrolyte solution 12 corresponds to the thin film portion 22. To do.

  The principle that the conductive polymer layer expands and contracts is mainly due to the bulky ion doping inside the conductive polymer layer. Further, ions to be doped are attracted from the electrolyte solution 12 through the conductive polymer layer to the working electrode 13. Therefore, if an insulating layer is interposed between the conductive polymer layer and the electrolyte solution 12, diffusion of ions to the conductive polymer layer in the portion where the insulating layer is provided is inhibited, and the electrolyte solution 12 The conductive polymer layer in the exposed portion is doped with ions, and electric field expansion and contraction occurs, and a force for twisting the linear member 23 can be generated.

  The electrolyte solution 12 includes an electrolyte for expanding and contracting the thin film portion 22 when a voltage is applied to the thin film portion 22 and a solvent for dissolving the electrolyte. As the electrolyte, sodium (Na), lithium (Li), potassium (K), or the like can be used. Moreover, water, an organic solvent, etc. can be used as said solvent.

Hereinafter, the operation of the actuator device 100 will be described.
As shown in FIG. 1, in the actuator device 100, the spring-like structure 11 and the movable part 2 are accommodated in the internal space S, and further, the electrolyte solution 12 is filled. At this time, the movable portion 2 is so arranged that one end portion of the shaft portion 2b on the side where the disc portion 2a is provided is immersed in the electrolyte solution 12 and the other end portion opposite to the one end portion is exposed to the outside. Is provided. When the movable portion 2 reciprocates linearly, an intermediate portion between the one end portion and the other end portion of the shaft portion 2 b slides with respect to the sealing material 5 a and the guide member 6. The disk part 2a of the movable part 2 is formed such that its outer diameter is smaller than the inner diameter of the internal space S. That is, when the movable part 2 moves, the electrolyte solution 12 filled is It can flow between the disk portion 2a and the counter electrode 14.

  A voltage is applied to the working electrode 13 and the counter electrode 14 by the power supply 15 from an initial state where no voltage is applied. In the spring-like structure 11, since the spring portion 21 is formed of a conductive conductor, a voltage can be uniformly applied to the thin film portion 22. When a voltage is applied to the thin film portion 22, the dopant ions in the electrolyte solution 12 are doped and stretched. At this time, a torsional moment is generated in the spring portion 21 in an arbitrary cross section by the extension of the thin film portion 22 in the spiral direction. Due to the generation of the torsional moment, the spring-like structure 11 is extended along the extension direction, that is, the direction of the axis J2. Then, the movable portion 2 is pressed by the spring-like structure 11 by the extension of the spring-like structure 11, and the disk portion 2a is moved in a direction close to the step surface.

  In addition, when the spring-like structure 11 is extended, that is, in a state where the thin film portion 22 is doped with dopant ions, the polarity of the power source 15 is reversed and voltage is applied to the working electrode 13 and the counter electrode 14. The thin film portion 22 is dedoped with the dopant ions doped in the thin film portion 22, and contracts from the stretched state to recover to the original state. Thereby, the torsional moment disappears, and the spring portion 21 returns to the original state by its own elastic recovery force. Accordingly, the movable part 2 fixed to the other end winding part of the spring-like structure 11 moves to the original position.

  Thus, according to the spring-like structure 11, the extension in the axis J3 direction of the thin-film portion 22 extending spirally is converted into the extension in the axis J1 direction of the spring portion 21, and further the axis J1 direction of the spring portion 21 Can be converted into the extension of the spring-like structure 11 in the direction of the axis J2. And by such conversion of elongation, the spring-like structure 11 can be expanded in the direction of the axis J2 with an expansion amount larger than the expansion amount that the thin film portion 22 extends. That is, a large generated force can be generated.

  Hereinafter, the reason why the spring-like structure 11 can be extended by an extension amount larger than the extension amount by which the thin film portion 22 extends will be described.

  Consider the unit length of the spring portion 21 wound spirally, that is, the length corresponding to one turn (one pitch) of the thin film portion 22. Here, the unit length of the spring portion 21 is L, the helical length of one turn of the thin film portion 22 is K, the outer diameter of the spring portion 21 is d, and the coil diameter of the spring portion 21 is D. .

It is assumed that the expansion ratio of the thin film portion 22 is Q [%]. At this time, the spring portion 21 is twisted by the extension of the thin film portion 22. Here, assuming that one end of the spring portion 21 having a unit length is fixed, the end portion of the thin film portion 22 on the other end side of the spring portion 21 is only ΔY along the circumferential direction of the spring portion 21. Displace. At this time, assuming that the twist angle of the spring portion 21 having a unit length is Δθ, Δθ = ΔY / (π × d) (where ΔY = −π × d + √ {(0.01 × Q × K) ² −K ² }). Therefore, if the extension amount per unit length L of the spring portion 21 in the expansion / contraction direction of the spring-like structure 11 is Δδ, it can be expressed as Δδ = D × tan (Δθ).

  Calculate by applying specific numerical values. It is assumed that D = 10 [mm], d = 2 [mm], L = 1 [mm], and Q = 2 [%]. At this time, the extension amount of the thin film portion 22 in the spring portion 21 having a unit length is calculated to be 0.127 mm. Further, the extension amount Δδ per unit length of the spring portion 21 in the expansion / contraction direction of the spring-like structure 11 is calculated as 1.28 mm. In other words, the spring-like structure 11 is stretched by a stretch amount larger than the stretch amount by which the thin film portion 22 stretches. The extension amount of the spring-like structure 11 can be increased as a function of the coil diameter D and the effective number of turns n of the spring portion 21.

  Table 1 shows the relationship between the lead angle and the twist angle when d = 2 [mm] and Q = 2 [%]. In addition, the lead angle in Table 1 corresponds to unit length L = 1 [mm], 2 [mm], 3 [mm], 4 [mm], and 5 [mm] in order from the top.

  As shown in Table 1, since the increment of the twist angle is not the same as the increment of the lead angle, the smaller the lead angle, the larger the expansion / contraction amount δ of the spring portion 21 as a whole.

  FIG. 3 is a view for explaining a spring-like structure 11a constituting the actuator element 1a according to the second embodiment. FIG. 3A is an enlarged view of a part of the spring-like structure 11a. FIG. 3B is a cross-sectional view taken along section line III-III in FIG.

  In the actuator element 1 according to the first embodiment, the case where the linear member 23 is a conductor has been described as the configuration of the spring-like structure 11, but in the actuator element 1a according to the second embodiment, the spring-like structure 11 is spring-like. The linear member 23a in the structure 11a is formed of an insulator having electrical insulation. The actuator element 1a according to the second embodiment is configured in the same manner as the actuator element 1 according to the first embodiment with respect to the remaining configuration except for the spring-like structure 11a. In the second embodiment, the same reference numerals are given to the same configurations as those in the above-described embodiments, and the same descriptions are omitted.

  In the actuator element 1a, the spring portion 21a is constituted by a linear member 23a formed of an insulator and an electrode layer 24a extending spirally along the axis J1 of the linear member 23a. The linear member 23a is preferably formed of, for example, polyacetal or Teflon (registered trademark). The electrode layer 24a has conductivity and is provided as an electrode layer that is laminated and fixed to the linear member 23a. The electrode layer 24a is preferably formed by plating and bonding metal.

  The thin film portion 22a is laminated and fixed to the electrode layer 24a. As in the first embodiment, the thin film portion 22a is formed by bonding a conductive polymer film formed in a long film shape to the electrode layer 24a by a known bonding means (for example, using an adhesive). It may be fixed by, for example. The thin film portion 22a may be formed so as to be laminated on the electrode layer 24a by electrolytic polymerization. The electrode layer 24a is electrically connected to a connecting end portion of the working electrode 13 connected to an end portion of one end winding portion of the spring portion 21a. Thereby, a voltage can be uniformly applied with respect to the thin film part 22a. In the present embodiment, the thin film portion 22a is laminated and fixed to the electrode layer 24a, but in other embodiments, the thin film portion 22a is directly bonded to the linear member 23a without providing the electrode layer 24a. Or you may make it extend along the spiral direction J3 by printing.

  Even when the spring-like structure 11a has such a configuration, the extension of the spirally extending thin film portion 22a can be converted into the extension of the spring-like structure 11a in the direction of the axis J2 of the spring portion 21a. it can. Then, by such extension conversion, the spring-like structure 11a can be extended with an extension amount larger than the extension amount of the thin film portion 22a. That is, a large generated force can be generated.

  FIG. 4 is a diagram for explaining the actuator element 1b according to the third embodiment, and FIG. 4A is a perspective view showing a part of the spring-like structure 11a in an enlarged manner. (B) is sectional drawing seen from the cut surface line IV-IV in Fig.4 (a).

In the actuator element 1a according to the second embodiment, as in the first embodiment, the electrolyte solution 12 is filled in the internal space S. However, in the actuator element 1b according to the third embodiment, the electrolyte is Instead of the solution 12, an electrolyte elastomer 12b is provided. As the electrolyte elastomer 12b, a gel in which the above-described electrolyte is contained in a water-absorbing polymer gel or an elastomer (rubber) in which an ionic liquid is blended can be used. As the ionic liquid, as a general one, for example, BMITFSI (1-butyl-3-methylimidazolium)
bis (trifluoromethanesulfonyl) imide) and the like.

  The actuator element 1b according to the third embodiment has a spring-like structure 11a in the actuator element 1a according to the second embodiment, and the electrolyte elastomer 12b is formed along the axis J1 of the spring portion 21a. It is provided so as to cover the outer periphery of 11a. By providing the electrolyte elastomer 12b instead of the electrolyte solution 12, the counter electrode 14b in the actuator element 1b is provided on the outer periphery of the electrolyte elastomer 12b. Note that the actuator element 1b according to the third embodiment is configured in the same manner as the actuator element 1a according to the second embodiment, except for the electrolyte elastomer 12b and the counter electrode 14b. In the third embodiment, the same reference numerals are given to the same configurations as those in the above-described embodiments, and the same descriptions are omitted.

  From an initial state in which no voltage is applied, a voltage is applied by the power source 15 to the working electrode 13 and the counter electrode 14b provided on the outer periphery of the electrolyte elastomer 12b. In the spring-like structure 11a, since the electrode layer 24a is formed of a conductive conductor, a voltage can be uniformly applied to the thin film portion 22a. When a voltage is applied to the thin film portion 22a, the dopant ions in the electrolyte elastomer 12b are doped and stretched. At this time, a torsional moment is generated in an arbitrary cross section in the spring portion 21a due to the extension of the thin film portion 22a in the spiral direction. Due to the generation of the torsional moment, the spring-like structure 11a is extended along the extension direction, that is, the direction of the axis J2. The movable portion 2 is pressed by the spring-like structure 11a by the extension of the spring-like structure 11a, and the disk portion 2a is moved in a direction close to the step surface.

  When the spring-like structure 11a is extended, that is, in a state where the thin film portion 22a is doped with dopant ions, the polarity of the power source 15 is reversed and voltage is applied to the working electrode 13 and the counter electrode 14b. The thin film portion 22a is dedoped with dopant ions doped in the thin film portion 22a, and contracts from the stretched state to recover to the original state. Thereby, the torsional moment disappears, and the spring portion 21a is restored to the original state by the elastic recovery force of the spring portion 21a. Accordingly, the movable part 2 fixed to the other end winding part of the spring-like structure 11a moves to the original position.

  Even when the actuator element 1b has such a configuration, the extension of the thin film portion 22a extending in a spiral shape can be converted into the extension of the spring-like structure 11a in the direction of the axis J2. Then, by such extension conversion, the spring-like structure 11a can be extended with an extension amount larger than the extension amount of the thin film portion 22a. That is, a large generated force can be generated.

  FIG. 5 is a perspective view schematically showing a configuration of an actuator device 100c according to the fourth embodiment. The actuator device 100c according to the fourth embodiment is configured by further providing a compression coil spring 6c to the actuator device 100 according to the first embodiment. In the actuator device 100c, the spring-like structure 11 is not fixed to the one surface portion of the bottom plate 4 and the disc portion 2a of the movable portion 2 in accordance with the provision of the compression coil spring 6c.

  The actuator device 100c according to the fourth embodiment is configured in the same manner as the actuator device 100 according to the first embodiment with respect to the remaining configuration except for the compression coil spring 6c. In the fourth embodiment, the same reference numerals are given to the same configurations as those in the previous embodiments, and the same descriptions are omitted.

  The actuator device 100c is attached to the housing 3 in a state where the movable portion 2 has the compression coil spring 6c inserted through the shaft portion 2b. That is, the compression coil spring 6 c is interposed between the stepped surface portion formed in the housing 3 and the surface portion on the side where the shaft portion 2 b is provided in the disc portion 2 a of the movable portion 2. Since the actuator device 100c is provided with such a compression coil spring 6c, when the coil spring member 11 is expanded by application of voltage, the compression coil spring 6c is compressed with respect to the coil spring member 11. The elastic recovery force generated by the above can be applied. That is, the thrust can be adjusted by the compression coil spring 6c.

  The fourth embodiment is not limited to such a configuration, and the actuator element 1 may be appropriately changed to the actuator element 1a according to the second embodiment and the actuator element 1b according to the third embodiment. .

  In the above embodiment, only the case where a conductive polymer is used as the thin film portion 22 that expands and contracts when a voltage is applied is described. However, the member used for the thin film portion 22 is formed of a conductive polymer. Not only the member but also other members having a property of expanding and contracting by applying a voltage, for example, a piezoelectric body such as zirconate titanate, and a carbon nanotube can be realized.

  In the embodiment described above, the case where the actuator device 100 is caused to function as an actuator using the actuator element 1 is described. However, for example, a voltmeter is opposed to the working electrode 13 instead of the power source 15 in the actuator element 1. It can also be used as a sensor element by being interposed between the electrodes 14.

  For example, in FIG. 1A, when a voltmeter is provided in place of the power source 15, the spring-like structure 11 moves along the axial direction P, that is, the axial direction J2, as the movable part 2 is displaced along the axial direction P. The thin film portion 22 expands and contracts as the spring-like structure 11 expands and contracts. Expansion and contraction of the thin film portion 22 is caused by doping / dedoping of ions from the electrolyte solution 12, and a potential difference is generated between the working electrode 13 and the counter electrode 14 by doping / dedoping of the ions. Thus, by utilizing the reverse principle, the potential difference between the working electrode 13 and the counter electrode 14 can be measured with a voltmeter to function as a sensor.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Actuator element 2 Movable part 3 Housing | casing 4 Bottom plate 5a, 5b, 5c Sealing material 6c Compression coil spring 11, 11a Spring-like structure 12 Electrolyte solution 12b Electrolyte elastomer 13 Working electrode 14, 14b Counter electrode 15 Power supply 21, 21a Spring portion 22, 22a Thin film portion 23, 23a Linear member 24a Electrode layer S Internal space 100, 100c Actuator device

Claims (3)

A coil-shaped spring portion formed by winding a linear member in a spiral shape, and extending and contracting;
An actuator element comprising a spring-like structure having a thin film portion having a property of expanding and contracting when a voltage is applied,
The actuator element, wherein the thin film portion is provided fixed to an outer peripheral portion of the spring portion, and extends spirally along an axis of the spring portion.   The actuator element according to claim 1, wherein the thin film portion is formed of a conductive polymer.   3. The spring part according to claim 1 or 2, wherein an electrode layer is spirally provided along the axis of the spring part, and the thin film part is provided on the electrode layer in a spiral form. The actuator element described.

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