JP2008251833A - Actuator, and actuator convergence object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator which can easily be miniaturized, is flexible and which has a large displacement amount. <P>SOLUTION: The actuator 1 is provided with a rod-like core material 2 which can elastically be deformed in an axial direction, which hardly has a volume change by elastic deformation and which has a side peripheral face continuing in the axial direction, and a cylindrical actuator element 3 which has a dielectric film 300 which is circularly arranged at a periphery of the core material 2 and is formed of dielectric elastomer, and a plurality of electrodes 301 disposed through the dielectric film 300 and in which the dielectric film 300 expands as applied voltage between the electrodes 301 becomes larger. The actuator element 3 is circularly arranged in the core material 2 in a state where it is previously and elastically deformed in the axial direction. The core material 2 is stopped in the state where elastic restoring force of the core material 2 and force of constraint of the actuator element 3 with respect to the core material 2 are balanced. The dielectric film 300 is expanded by impressing voltage between the electrodes 301, and force of constraint is reduced. Thus, elastic restoring force of the core material 2 is used and driving force is outputted in the axial direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an actuator that outputs a driving force by expansion and contraction of a dielectric film according to an applied voltage, and an actuator focusing body.

  In the fields of industrial and nursing robots, medical equipment, micromachines, and the like, there is an increasing need for highly flexible, small, and lightweight actuators. As such an actuator material, for example, various polymers such as a conductive polymer, an ion conductive polymer (ICPF), and a dielectric elastomer have been proposed.

  For example, as an electrostrictive actuator using a dielectric elastomer, Patent Document 1 introduces a roll-type actuator. That is, the actuator described in Patent Document 1 includes an actuator element having a dielectric elastomer film and an electrode, which is mounted on the outer periphery of a compressed coil spring. When a voltage is applied to the electrode of the actuator element, the thickness of the dielectric elastomer film decreases, and the dielectric elastomer film extends in the axial direction. Thereby, the restraining force with respect to the coil spring is reduced, and the coil spring, that is, the actuator extends in the axial direction.

Patent Document 2 introduces an actuator including a cylindrical actuator element composed of a dielectric elastomer film and an electrode. When a voltage is applied to the electrode of the actuator element, like the actuator described in Patent Document 1, the thickness of the dielectric elastomer film decreases, and the dielectric elastomer film extends in the axial direction. As a result, the actuator extends in the axial direction.
Special table 2006-520180 gazette Japanese Patent Laying-Open No. 2003-230288

  In the case of the actuator of Patent Document 1, when a voltage is applied and the actuator element extends, the coil spring disposed on the inner diameter side of the actuator element extends without changing the diameter. For this reason, the actuator element and the coil spring interfere with each other at the time of extension, and the axial displacement of the actuator may be hindered. On the contrary, when the voltage application is stopped, the actuator element contracts in the axial direction. The coil spring is compressed in the axial direction by the restraining force from the contracting actuator element. Here, when shrinking, the thickness of the dielectric elastomer film, which has been reduced by the application of voltage, increases to restore the original thickness. On the other hand, the coil spring contracts without changing its diameter. For this reason, the actuator element and the coil spring interfere with each other at the time of contraction, and the actuator element may be bitten by the pitch of the coil spring, for example. Moreover, the actuator of patent document 1 uses a coil spring as a core material. For this reason, it is difficult to make the actuator thin and small. Furthermore, since the coil spring is a rigid body, it is difficult to realize a flexible movement.

  Further, in the case of the actuator of Patent Document 2, the actuator element is displaced by the amount that is extended from the natural state. However, the actuator of Patent Document 2 is not provided with a member that orients the extending direction of the actuator element. For this reason, according to the actuator of Patent Document 2, it is difficult to align the extension direction in one direction. Therefore, the amount of displacement in the axial direction is small.

  The present invention has been completed in view of such circumstances, and an object of the present invention is to provide an actuator that can be easily downsized, is flexible, and has a large amount of displacement.

  (1) In order to solve the above problems, the first actuator of the present invention is elastically deformable in the axial direction, has almost no volume change due to elastic deformation, and has a rod-like shape having a side peripheral surface continuous in the axial direction. A core material, a dielectric film made of a dielectric elastomer that is wrapped around the core material, and a plurality of electrodes disposed via the dielectric film, and an applied voltage between the electrodes is A cylindrical actuator element in which the dielectric film expands as the size increases, and the actuator element is preliminarily mounted on the core material that is elastically deformed in the axial direction in advance. In a state where the restoring force and the restraining force of the actuator element with respect to the core material are balanced, the core material is stopped, and by applying a voltage between the electrodes, the dielectric film is stretched, and the restraining force is increased. By making small, the elastic restoring force of the core material And use, characterized in that capable of outputting driving force in the axial direction (corresponding to claim 1).

  Hereinafter, the operation of the first actuator of the present invention (hereinafter referred to simply as “the actuator of the present invention” in the present configuration. The same applies to configurations (2) to (4)) will be described using the principle diagram. However, FIGS. 1 and 2 shown below are only for explaining the operation of the actuator of the present invention, and do not limit the configuration, shape, and the like of the actuator of the present invention. For example, the number of laminated dielectric films, the thickness of electrodes or dielectric films, the number of electrodes arranged, the shape of the core material, and whether the core material is solid or hollow are not limited at all.

  First, FIG. 1 shows a principle diagram of an actuator element in the actuator of the present invention. (A) shows a state before voltage application, and (b) shows a state during voltage application. As shown in FIG. 1, the actuator element b includes a dielectric film b1 and an electrode b2. The electrode b2 is disposed on both surfaces of the dielectric film b1. The electrode b2 forms an electric circuit together with the switch d2 and the power source d1. As shown in FIG. 1B, when the switch d2 is closed, a voltage is applied between the electrodes b2. Thereby, the electrostatic attractive force between the electrodes b2 is increased. For this reason, the dielectric film b1 is deformed so as to contract in the film thickness direction as indicated by the white arrow in FIG. In addition, the dielectric film b1 is deformed so as to extend in the surface development direction. Therefore, the actuator element b extends by the distance L1 in the surface development direction.

  Next, the principle diagram of the actuator of the present invention using the actuator element b of FIG. 1 is shown in FIG. (A) shows a state before voltage application, and (b) shows a state during voltage application. As shown in FIG. 2, the actuator a includes a core material c and an actuator element b. The actuator element b is wrapped around the core material c. In FIG. 2, the core material c is elastically compressed in advance in the axial direction with respect to the natural state (of course, it may be expanded in advance). That is, the actuator element b is wrapped around the core material c in a state of being elastically compressed and deformed in the axial direction in advance. For this reason, in FIG. 2A, the elastic restoring force (extension force) F1 of the core material c and the restraining force F2 of the actuator element b with respect to the core material c are balanced.

  In this state, when a voltage is applied between the electrodes b2, the actuator element b extends by a distance L1, as shown in FIG. For this reason, the restraining force F2 becomes small by that much. Therefore, as shown in FIG. 2B, the actuator a is extended by the distance L2 by the elastic restoring force F1 of the core material c as much as the restraining force F2 is reduced. The extension of the actuator a stops again at a position where the elastic restoring force F1 and the restraining force F2 are balanced.

  As described above, the actuator a according to the present invention changes the balance position between the elastic restoring force F1 and the restraining force F2 by changing the restraining force F2, thereby extending or contracting the actuator a, thereby increasing the driving force. Output.

  The core material of the actuator of the present invention has a rod shape, and its volume hardly changes even when elastically deformed. That is, the diameter is reduced when extending in the axial direction, and the diameter is increased when contracting. For this reason, according to the actuator of this invention, a core material and an actuator element do not interfere easily at the time of expansion | extension. The core member has a side peripheral surface that is continuous in the axial direction. For this reason, even if it compresses, there is no possibility that an actuator element may be bitten like a coil spring, for example.

  According to the actuator of the present invention, the expansion / contraction direction of the actuator element is oriented in the axial direction by the core material. For this reason, the amount of axial displacement is large. The actuator of the present invention expands and contracts due to a change in the balance position between the elastic restoring force of the core member and the restraining force of the actuator element, and outputs a driving force. For this reason, stable operation is possible regardless of the attitude of the actuator. The actuator element is wrapped around the core material. For this reason, it is easy to miniaturize. In addition, by changing the type, the number of stacked layers, the film thickness, the number of electrode pairs, the arrangement, and the like of the dielectric film, it is possible to easily adjust the driving force and the displacement amount in the actuator of the present invention.

  (2) Preferably, in the configuration of the above (1), the core material is made of an elastomer (corresponding to claim 2).

  The Poisson's ratio of the elastomer is close to 0.5. For this reason, volume change due to elastic deformation hardly occurs. Moreover, according to the elastomer, core materials of various sizes and shapes can be easily produced. For example, it is easy to produce a thinner and smaller core using extrusion processing, spinning technology, or the like. Thereby, the actuator of the present invention can be made thinner and smaller. Further, by making the core material made of an elastomer, more flexible movement can be realized. Thus, according to the present configuration, for example, application to artificial muscles is facilitated.

  (3) Preferably, in the configuration of (1) or (2), the actuator element includes the dielectric film, the pair of electrodes disposed on both surfaces of the dielectric film, and one of the pair of electrodes. A stretchable film having an insulating film disposed on the surface of the core member may be wound around the core material in a spiral shape (corresponding to claim 3).

  According to this structure, the actuator of this invention can be easily produced by winding a predetermined elastic film around a core material. In addition, it is easy to adjust the number of turns of the stretch film. Thereby, a desired driving force and displacement amount can be easily obtained. In the stretchable film, an insulating film is disposed on one electrode surface. For this reason, in the wound stretchable film, adjacent electrodes do not contact each other. Therefore, conduction between adjacent electrodes can be prevented.

  (4) Preferably, in the configuration of the above (1) or (2), the actuator element may be configured such that the dielectric films and the electrodes are alternately and concentrically stacked around the core material. (Corresponding to claim 4).

  According to this configuration, the actuator of the present invention can be easily manufactured. Further, by adjusting the number of dielectric films to be laminated, etc., a desired driving force and displacement amount can be easily obtained. In addition, in each of the laminated dielectric film layers, the applied voltage can be efficiently used for extending the dielectric film.

  (5) Moreover, in order to solve the said subject, the 2nd actuator of this invention has a dielectric film made from a dielectric elastomer, and the some electrode arrange | positioned through this dielectric film, A cylindrical actuator element in which the dielectric film expands as the applied voltage between the electrodes increases, and a hollow part disposed at the shaft part of the actuator element. The hollow part includes a compressed gas And is deformed according to the expansion force of the compressed gas by increasing the voltage applied between the electrodes and extending the dielectric film (corresponding to claim 5).

  The second actuator of the present invention (hereinafter referred to simply as “the actuator of the present invention” in the present configuration. The same applies to configurations (6) to (10)) is used as the core material in the first actuator of the present invention. Instead, it includes a hollow portion filled with compressed gas. A cylindrical actuator element is disposed around the hollow portion. The actuator element is arranged in a state of being expanded by the expansion force of the compressed gas. Here, the expansion force of the compressed gas and the restraining force of the actuator element are balanced.

  As described above with reference to FIG. 1, when a voltage is applied between the electrodes of the actuator element, the actuator element expands in the surface development direction. For this reason, the restraining force with respect to the hollow part of an actuator element becomes small by that much. Therefore, the actuator element expands by the expansion force of the compressed gas by the amount that the restraining force is reduced. That is, the actuator of the present invention expands. On the other hand, when the application of voltage is stopped, the actuator element contracts in the surface expansion direction. Here, the actuator element contracts while compressing the gas filled in the hollow portion. The actuator of the present invention contracts to a position where the restraining force of the actuator element and the expansion force of the compressed gas are balanced.

  As described above, the actuator of the present invention changes the balance position between the expansion force and the constraint force of the compressed gas by changing the constraint force with respect to the hollow portion, and expands or contracts the actuator, and outputs the drive force. Is. Therefore, stable operation is possible regardless of the attitude of the actuator. Moreover, since a core material is unnecessary, it is easy to reduce the size. In addition, by changing the physical properties of the compressed gas, filling pressure, type of dielectric film, number of stacked layers, film thickness, number of electrode pairs, arrangement, etc., the driving force and displacement amount of the actuator of the present invention can be easily adjusted. can do.

  (6) Preferably, in the configuration of (5), the actuator element is disposed on the dielectric film, the pair of electrodes disposed on both surfaces of the dielectric film, and one surface of the pair of electrodes. It is preferable that the stretchable film including the insulating film is wound around the hollow portion in a spiral shape (corresponding to claim 6).

  According to this configuration, the actuator of the present invention can be easily manufactured by winding a predetermined stretch film. In addition, it is easy to adjust the number of turns of the stretch film. Thereby, a desired driving force and displacement amount can be easily obtained. In the stretchable film, an insulating film is disposed on one electrode surface. For this reason, in the wound stretchable film, adjacent electrodes do not contact each other. Therefore, conduction between adjacent electrodes can be prevented.

  (7) Preferably, in the configuration of the above (5), the actuator element may be configured such that the dielectric film and the electrode are alternately and concentrically stacked around the hollow portion. Corresponding).

  According to this configuration, the actuator of the present invention can be easily manufactured. Further, by adjusting the number of dielectric films to be laminated, etc., a desired driving force and displacement amount can be easily obtained. In addition, in each of the laminated dielectric film layers, the applied voltage can be efficiently used for extending the dielectric film.

  (8) Preferably, in any one of the configurations (5) to (7), the hollow portion may be formed in a bag shape by the actuator element (corresponding to claim 8). According to this structure, it is not necessary to use a new part in order to form a hollow part. That is, the number of parts may be small.

  (9) Preferably, in any one of the above configurations (5) to (8), the configuration may further include a shape retaining member for retaining the shape of the hollow portion (corresponding to claim 9). According to this structure, a hollow part can be formed in a desired shape with a shape-retaining member. In addition, when the shape retaining member is used, the actuator element can be easily arranged. For this reason, the production of the actuator of the present invention is facilitated. In addition, the deformation direction of the actuator element can be easily set to a desired direction.

  (10) Preferably, in the configuration of any one of (5) to (9), a valve capable of filling the hollow portion with the compressed gas is further provided (corresponding to claim 10). According to this configuration, it is easy to fill the hollow portion with the compressed gas. Moreover, when discharge is necessary (of course, it is not necessary to discharge), discharge becomes easy. Therefore, for example, when the pressure (expansion force) of the compressed gas is lowered during use, the compressed gas can be replenished and maintenance is easy.

  (11) Preferably, in any one of the configurations (1) to (10), the maximum diameter in the axial direction is less than 5 mm (corresponding to claim 11). As described above, the first actuator of the present invention includes a rod-shaped core member and an actuator element that is provided around the rod-shaped core member. Moreover, the 2nd actuator of this invention is equipped with a cylindrical actuator element and the hollow part arrange | positioned at the axial part. The sizes of the first and second actuators of the present invention (hereinafter referred to as “actuators of the present invention” collectively unless otherwise specified) are particularly limited. Is not to be done. For example, according to this configuration, it is possible to configure a thin string-like actuator having a maximum diameter in the axial direction of less than 5 mm. In this case, it is possible to drive at a lower voltage. Furthermore, a finer fibrous actuator may be configured with the maximum diameter in the axial direction being less than 0.5 mm. These string-like and fiber-like actuators are suitable for artificial muscles.

  (12) Preferably, in any one of the configurations (1) to (11), the electrode may be composed of a mixture of an elastomer and a conductive material (corresponding to claim 12). If the electrode is difficult to expand and contract together with the dielectric film, the electrode prevents the expansion and contraction of the dielectric film. In this regard, according to the present configuration, the electrode is made of a mixed material containing a flexible elastomer in addition to the conductive material. Therefore, the electrode can be extended and contracted integrally with the dielectric film. For this reason, it is difficult to prevent expansion and contraction of the dielectric film, and a desired amount of displacement is easily obtained.

  (13) The actuator focusing body of the present invention is characterized in that a plurality of the actuators having any one of the constitutions (1) to (12) are bundled (corresponding to claim 13). A larger driving force can be output by bundling a plurality of the actuators of the present invention. In particular, when the actuator of the present invention has a string shape or a fiber shape, it is suitable as the actuator focusing body of the present invention.

  Hereinafter, embodiments of the actuator and the actuator focusing body of the present invention will be described.

<First embodiment>
[Configuration of actuator]
First, the configuration of the actuator of this embodiment will be described. FIG. 3 shows a perspective view of the actuator of this embodiment. FIG. 4 is an exploded perspective view of the actuator. FIG. 5 shows a cross-sectional view in the direction perpendicular to the axis of the actuator. FIG. 6 shows an axial sectional view of the actuator. As shown in FIGS. 3 to 6, the actuator 1 of this embodiment includes a core material 2 and an actuator element 3.

  The core material 2 is made of an elastomer and has a round bar shape. The actuator element 3 has a cylindrical shape. The actuator element 3 is composed of a belt-shaped stretch film 30. The actuator element 3 is wrapped around the outer peripheral surface of the core material 2. Specifically, the actuator element 3 is wrapped around the core material 2 by winding the stretchable film 30 around the outer peripheral surface of the core material 2 in a spiral shape. The stretchable film 30 is wound around a core material 2 that is elastically stretched in the axial direction in advance. This point will be described in detail later.

  The stretchable film 30 includes a dielectric film 300, an electrode 301, and an insulating film 302. The dielectric film 300 is made of acrylic rubber. The electrode 301 is made of an elastomer film (mixed material) obtained by mixing conductive carbon and an elastomer. A pair of electrodes 301 are disposed on both surfaces of the dielectric film 300. The electrode 301 is electrically connected to a power source and a switch as shown in FIG. The insulating film 302 is made of acrylic rubber, and is fixed to the outer peripheral surface of the radially outer electrode 301 of the pair of electrodes 301.

  As shown in FIG. 5, the stretchable film 30 is wound around the outer peripheral surface of the core material 2 so as to be approximately five layers. As shown by a dotted frame in FIG. 6, the core material 2, the innermost stretch film 30, and the stretch films 30 adjacent to each other in the radial direction are bonded to each other at both axial ends of the core material 2. The diameter of the actuator 1 in the direction perpendicular to the axis is about 5 mm.

[Actuator manufacturing method]
Next, a method for manufacturing the actuator 1 of the present embodiment will be described. In FIG. 7, the schematic diagram of the manufacturing method of the actuator 1 of this embodiment is shown. The manufacturing method of the actuator 1 of this embodiment has a core material extending | stretching process and an elastic membrane winding process. Fig.7 (a) is a side view which shows a core material expansion | extension process. FIG. 7B is a perspective view showing the stretch film winding process. In the core material extension step, as shown in FIG. 7A, the core material 2 in a natural state (indicated by a dotted line in FIG. 7A) is elastically extended in the axial direction. In the stretch film winding step, as shown in FIG. 7B, the stretch film 30 that has been prepared in advance is wound around the outer peripheral surface of the core material 2 in the stretched state. In this way, the actuator 1 of the present embodiment is manufactured.

  The core material 2 of the completed actuator 1 is restrained from the outside in the radial direction by the stretchable film 30. For this reason, the actuator 1 is stopped in a state where the elastic restoring force in the contracting direction of the core material 2 and the restraining force of the stretchable film 30 on the core material 2 are balanced.

[Actuator movement]
Next, the movement of the actuator 1 of this embodiment will be described. First, the movement during voltage application will be described. FIG. 8 is a sectional view in the axial direction during voltage application of the actuator 1 of the present embodiment. In FIG. 8, a dotted line indicates the shape of the core material 2 before voltage application (see FIG. 6). In the state shown in FIG. 6, when a voltage is applied between the pair of electrodes 301, the dielectric film 300 is compressed in the front and back direction (film thickness direction). For this reason, the film thickness of the dielectric film 300 becomes small. As the film thickness decreases, the area of the dielectric film 300 increases accordingly. Therefore, the dielectric film 300 extends together with the electrode 301 and the insulating film 302. That is, the stretch film 30 expands. When the stretchable film 30 is elongated, the restraint of the stretchable film 30 on the core material 2 is loosened accordingly. For this reason, the restraining force with respect to the core material 2 of the elastic membrane 30 becomes small. When the restraining force is reduced, the balance between the elastic restoring force in the contraction direction of the core material 2 and the restraining force of the stretchable film 30 on the core material 2 is lost. That is, the elastic restoring force is larger than the restraining force. Therefore, as shown in FIG. 8, the core material 2, that is, the actuator 1 is contracted and deformed by the elastic restoring force.

  Next, the movement at the time of voltage removal will be described. In the state shown in FIG. 8, when the voltage between the pair of electrodes 301 is removed, the compressive force acting on the front and back sides of the dielectric film 300 is removed. For this reason, the film thickness of the dielectric film 300 increases. As the film thickness increases, the area of the dielectric film 300 decreases accordingly. Therefore, the dielectric film 300 contracts together with the electrode 301 and the insulating film 302. That is, the stretch film 30 contracts. When the stretch film 30 contracts, the core material 2 is compressed from the radially outer side by the stretch film 30. Then, the core material 2 elastically expands in the axial direction by the amount compressed. Eventually, the actuator 1 stops at a position where the elastic restoring force in the contraction direction of the core material 2 that increases due to the expansion and the restraining force of the stretchable film 30 on the core material 2 are balanced. That is, the state returns to the state shown in FIG.

  As described above, the actuator 1 of the present embodiment is switched from the state of FIG. 6 to the state of FIG. 8 by voltage application. That is, it contracts. In addition, the state of FIG. 8 is switched to the state of FIG. 6 by voltage removal. That is, it expands. Thus, by contracting and extending, for example, a mating member (not shown) connected to the core member 2 can be driven.

[Function and effect]
Next, the effect of the actuator of this embodiment is demonstrated. According to the actuator 1, the core material 2 is made of an elastomer. For this reason, a flexible movement is possible. Even a small diameter can be easily produced from an elastomer. Further, the core material 2 hardly changes in volume even when elastically deformed. That is, the diameter is reduced when extending in the axial direction, and the diameter is increased when contracting. For this reason, in the actuator 1, the core material 2 and the stretchable film 30 (actuator element 3) are unlikely to interfere with each other during expansion and contraction. In addition, the core material 2 has a round bar shape. That is, the side peripheral surface of the core material 2 is continuous in the axial direction. Therefore, there is no possibility that the stretch film 30 is bitten by the core material 2 during compression.

  The actuator 1 expands and contracts due to a change in the balance position between the elastic restoring force of the core member 2 and the restraining force of the stretchable film 30 and outputs a driving force. For this reason, stable operation is possible regardless of the attitude of the actuator 1. Further, according to the actuator 1, the expansion / contraction direction of the expansion / contraction film 30 is restricted in the axial direction by the core material 2. For this reason, the amount of axial displacement is large. Further, the electrode 301 and the insulating film 302 are deformed integrally with the dielectric film 300. For this reason, the deformation of the dielectric film 300 is not easily disturbed by the electrode 301 and the insulating film 302. Therefore, it is easy to obtain a desired amount of displacement and there is little decrease in driving force.

  The stretchable film 30 is wound around the core material 2 in approximately five layers. As shown in FIG. 7, the actuator 1 can be easily manufactured by simply winding the stretchable film 30 around the stretched core material 2. Furthermore, the actuator 1 can be configured compactly. Further, in the wound stretchable film 30, an insulating film 302 is disposed on the outer peripheral surface of the radially outer electrode 301. For this reason, adjacent electrodes 301 do not contact each other. Therefore, conduction between adjacent electrodes 301 can be prevented. In addition, since the stretchable film 30 can be expanded and contracted simply by applying and removing a voltage to the pair of electrodes 301, electrical wiring is easy. Moreover, since the diameter of the actuator 1 is as small as about 5 mm, the actuator 1 is suitable as an artificial muscle, for example.

<Second embodiment>
The difference between the actuator of the present embodiment and the actuator of the first embodiment is that the stretchable film is wound in a compressed state, not in a state in which the core material is expanded with respect to the natural state. Therefore, only the differences will be described here.

  FIG. 9 shows a schematic diagram of the manufacturing method of the actuator of this embodiment. In addition, about the site | part corresponding to FIG. 7, it shows with the same code | symbol. The manufacturing method of the actuator of this embodiment has a core material compression process and a stretch film winding process. Fig.9 (a) is a side view which shows a core material compression process. FIG. 9B is a perspective view showing the stretch film winding process. In the core material compression step, as shown in FIG. 9A, the core material 2 in a natural state (indicated by a dotted line in FIG. 9A) is elastically compressed in the axial direction. In the stretch film winding step, as shown in FIG. 9B, the stretch film 30 that has been prepared in advance is wound around the outer peripheral surface of the core material 2 in a compressed state. In this way, the actuator of this embodiment is manufactured.

  FIG. 10 is a cross-sectional view in the axial direction during voltage application of the actuator of this embodiment. In addition, about the site | part corresponding to FIG. 8, it shows with the same code | symbol. In FIG. 10, the dotted line indicates the shape of the actuator before voltage application.

  The actuator 1 of the present embodiment moves in the opposite direction to the first embodiment. In addition, the same movement as the principle diagram of FIG. 2 is performed. That is, when a voltage is applied, the restraining force of the stretchable film 30 on the core material 2 is reduced. For this reason, the core material 2, that is, the actuator 1 is extended by the elastic restoring force in the extending direction. On the other hand, when the voltage is removed, the stretch film 30 contracts in the axial direction. As shown by the dotted frame in FIG. 6 of the first embodiment, at both ends in the axial direction of the core material 2, the core material 2, the innermost stretch film 30, and the stretch films 30 adjacent in the radial direction are mutually It is glued. For this reason, when the stretch film 30 contracts in the axial direction, the core material 2 also contracts in the axial direction while accumulating elastic restoring force in the extension direction. Therefore, the actuator 1 also contracts in the axial direction. Thus, by extending and contracting, for example, the mating member (not shown) connected to the core member 2 can be driven.

  The actuator 1 of the present embodiment has the same operational effects as the actuator of the first embodiment.

<Third embodiment>
The difference between the actuator of this embodiment and the actuator of the first embodiment is that the configuration of the actuator element is different. Therefore, only the differences will be described here.

  FIG. 11 shows a cross-sectional view in the direction perpendicular to the axis of the actuator of this embodiment. In addition, about the site | part corresponding to FIG. 5, it shows with the same code | symbol. As shown in FIG. 11, an actuator element 3 having a cross section of an annual ring is provided around the outer peripheral surface of the core material 2 of the actuator 1 of the present embodiment. More specifically, electrodes 301 and dielectric films 300 are alternately stacked in the radial direction around the core material 2. The electrode 301 and the dielectric film 300 each have a cylindrical shape. That is, the electrodes 301 and the dielectric films 300 are alternately stacked concentrically. The arbitrary dielectric film 300 is sandwiched between a pair of electrodes 301 from both sides in the radial direction. The dielectric film 300 has a total of five layers, and the electrode 301 has a total of six layers.

  The actuator 1 of this embodiment can be manufactured by alternately dipping the core material 2 into an electrode material solution for forming the electrode 301 and a dielectric material solution for forming the dielectric film 300. Alternatively, the core material 2 may be manufactured by alternately spraying an electrode material solution and a dielectric material solution.

  The actuator 1 of the present embodiment has the same operational effects as those of the actuator of the first embodiment with respect to the parts having the same configuration. Further, when a voltage is applied between the electrodes 301, all the dielectric films 300 sandwiched between the electrodes 301 can be extended. For this reason, a driving force and a displacement can be generated more efficiently.

<Fourth embodiment>
The difference between the actuator of this embodiment and the actuator of the first embodiment is that the core material is not mainly disposed. Therefore, only the differences will be described here.

  FIG. 12 is a sectional view in the axial direction of the actuator of this embodiment. As shown in FIG. 12, the actuator 1 of this embodiment includes an actuator element 5, a hollow portion 6, and a valve 7. The diameter of the actuator 1 in the direction perpendicular to the axis is about 10 mm.

  The actuator element 5 has a bag shape. The actuator element 5 is formed by alternately stacking the electrodes 501 and the dielectric film 500 in the inner and outer directions. The arbitrary dielectric film 500 is sandwiched between a pair of electrodes 501 from both the inside and outside directions. The dielectric film 500 has a total of three layers, and the electrode 501 has a total of four layers.

  A hollow portion 6 is defined inside the innermost electrode 501. The valve 7 seals the opening of the actuator element 5. A compressed gas (for example, nitrogen) is sealed in the hollow portion 6 via a valve 7.

  FIG. 13 is a sectional view in the axial direction during voltage application of the actuator 1 of the present embodiment. When a voltage is applied to each electrode 501 so that the voltage applied to each dielectric film 500 becomes equal, the dielectric film 500 is compressed in the film thickness direction and expanded in the surface development direction. In addition, the electrode 501 also extends together with the dielectric film 500. Here, the hollow portion 6 is filled with compressed gas. Therefore, the actuator element 5 expands due to the expansion force of the compressed gas.

  When the voltage is removed, the compressive force acting in the film thickness direction of the dielectric film 500 is removed. For this reason, the dielectric film 500 contracts in the surface development direction. Therefore, the actuator element 5 also contracts while compressing the gas filled in the hollow portion 6. The actuator 1 stops at a position where the contraction force of the actuator element 5 and the gas expansion force of the hollow portion 6 are balanced. That is, the actuator 1 stops in the state shown in FIG.

  As described above, the actuator 1 of the present embodiment is switched from the state of FIG. 12 to the state of FIG. 13 by voltage application. That is, it expands. In addition, the state of FIG. 13 is switched to the state of FIG. 12 by voltage removal. That is, it contracts. Thus, by expanding and contracting, for example, a mating member (not shown) connected to the actuator element 5 can be driven.

  The actuator 1 of the present embodiment has the same operational effects as those of the actuator of the first embodiment with respect to the parts having the same configuration. Further, the actuator 1 of the present embodiment expands and contracts due to a change in the balance position between the expansion force of the compressed gas in the hollow portion 6 and the restraining force of the actuator element 5, and outputs a driving force. For this reason, stable operation is possible regardless of the attitude of the actuator 1. Moreover, according to the actuator 1 of this embodiment, a wide driving force can be generated by adjusting the filling pressure of the compressed gas.

  Further, according to the actuator 1 of the present embodiment, the hollow portion 6 is formed in a bag shape by the actuator element 5. For this reason, it is not necessary to use a new part to form the hollow portion 6. Further, since the valve 7 is disposed in the hollow portion 6, the compressed gas can be easily filled and discharged via the valve 7.

<Others>
The embodiment of the actuator of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  For example, in the first to third embodiments, a round bar-shaped core material is used. However, the shape and size of the core material are not particularly limited. The core material may be solid or hollow. Further, the core material may be any material that can be elastically deformed in the axial direction, has almost no volume change due to elastic deformation, and has a side peripheral surface continuous in the axial direction. Examples of the core material include silicone rubber, acrylic rubber, ethylene-propylene-diene terpolymer (EPDM), natural rubber (NR), butyl rubber (IIR), isoprene rubber (IR), acrylonitrile- Elastomers such as butadiene copolymer rubber (NBR), hydrogenated nitrile rubber (H-NBR), hydrin rubber, chloroprene rubber (CR), fluorine rubber, and urethane rubber are suitable.

  In the above embodiment, a dielectric film made of acrylic rubber is used. However, the material of the dielectric film is not particularly limited as long as it is deformable according to the electrostatic attractive force between the pair of front and back electrodes. For example, examples of the dielectric elastomer having high dielectric property and high dielectric breakdown strength include silicone rubber, fluorine rubber, and urethane rubber in addition to the acrylic rubber. Further, the shape and thickness of the dielectric film are not particularly limited, and may be appropriately determined according to the use of the actuator. For example, it is desirable that the thickness of the dielectric film is small from the viewpoints of downsizing the actuator, driving at a low potential, and increasing the amount of displacement. In this case, the dielectric film thickness is preferably 1 μm or more and 1000 μm (1 mm) or less in consideration of dielectric breakdown strength and the like. More preferably, the thickness is 5 μm or more and 200 μm or less.

  The material of the electrode is not limited to the above embodiment, but it is desirable that the electrode can be expanded and contracted according to the expansion and contraction of the dielectric film. When the electrode expands and contracts together with the dielectric film, the deformation of the dielectric film is not easily disturbed by the electrode, and a desired displacement amount can be obtained more easily. For example, an electrode may be formed by applying a paste or paint in which oil or elastomer is mixed as a binder to a conductive material made of a carbon material such as carbon black or carbon nanotube. Examples of the elastomer used as the binder include silicone rubber, acrylic rubber, ethylene-propylene-diene terpolymer (EPDM), natural rubber (NR), butyl rubber (IIR), isoprene rubber (IR), and acrylonitrile-butadiene copolymer. Flexible materials such as polymer rubber (NBR), hydrogenated nitrile rubber (H-NBR), hydrin rubber, chloroprene rubber (CR), urethane rubber and the like are suitable. Moreover, in order to further improve the stretchability of the dielectric film, conductive electrodes such as carbon black and carbon nanotubes may be directly attached to the surface of the dielectric film to form an electrode.

  In the first and second embodiments, the actuator element is configured by winding a stretchable film having an insulating film. Here, the material of the insulating film is not particularly limited as long as conduction between adjacent electrodes can be prevented. For example, like the electrode, it is desirable that it can be expanded and contracted according to the expansion and contraction of the dielectric film. For example, silicone rubber, acrylic rubber, ethylene-propylene-diene terpolymer (EPDM), natural rubber (NR), butyl rubber (IIR), isoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), hydrogen Flexible materials such as nitrile rubber (H-NBR), hydrin rubber, chloroprene rubber (CR), and urethane rubber are suitable. When the insulating film is made of the same material as that of the dielectric film, a larger driving force can be obtained.

  In the first and second embodiments, the insulating film is disposed so as to cover the entire surface of the electrode. However, as long as conduction between adjacent electrodes can be prevented, the insulating film may be disposed only on a part of the surface of the electrode. Further, when the outermost layer of the actuator element is an insulating film made of a dielectric elastomer as in the first and second embodiments, an electrode may be further arranged on the surface. In this case, since the outermost insulating film can be deformed in the same manner as the dielectric film, a larger driving force can be obtained.

  In the first to third embodiments, the diameter of the actuator in the axial direction is about 5 mm, and in the fourth embodiment, the diameter is about 10 mm. However, the size of the actuator of the present invention in the axial direction and the axial direction is not particularly limited. Moreover, the actuator of the said embodiment may be used independently, and may be bundled and it may be set as the actuator focusing body of this invention. In this way, a larger driving force can be output. In particular, the string-like actuator as in the above embodiment and the finer fiber-like actuator are suitable for the actuator focusing body of the present invention. The string-like actuator of the above-described embodiment and the actuator focusing body in which the string-like actuator is bundled are useful as, for example, an artificial muscle. A plurality of actuators of the above embodiment may be used by knitting by knitting. Furthermore, the actuator focusing body of the present invention may be similarly knitted and used.

  In the first and second embodiments, the actuator is configured by winding the stretchable film in approximately five layers, that is, by laminating the dielectric film in approximately five layers. In the third and fourth embodiments, the dielectric films are laminated in five layers and three layers, respectively. However, the number of laminated dielectric films (the number of turns of the stretch film) is not particularly limited. When the number of stacked dielectric films is increased, the driving force can be further increased.

  Further, there are no particular limitations on the fixing location and fixing method of the core material and the stretch film, between the stretch films, the electrode and the dielectric film. Both ends of the core material in the axial direction may be caulked and fixed, or the core material and the stretchable film may be bonded over the entire axial direction.

  Moreover, in the said 4th embodiment, the kind of gas with which a hollow part is filled is not specifically limited. For example, a gas having a large volume change with respect to a pressure change is desirable. Moreover, you may arrange | position the shape-retaining member for hold | maintaining the shape of a hollow part.

  In the above embodiment, the actuator is operated by switching from the off state (0 V) to the on state. However, the voltage value before operation is not necessarily 0V. For example, the applied voltage may be increased from a predetermined voltage value.

  The actuator and actuator focusing body of the present invention are useful for, for example, power assist suits, artificial muscles for industrial, medical, and welfare robots, small pumps for cooling and medical electronic parts, medical instruments, and the like. It can be used as an alternative to all actuators such as mechanical actuators such as motors and piezoelectric element actuators.

It is a principle figure of the actuator element in the actuator of this invention. It is a principle diagram of the actuator of the present invention. It is a perspective view of the actuator of a first embodiment of the present invention. It is a perspective exploded view of the actuator. FIG. 3 is a cross-sectional view perpendicular to the axis of the actuator. It is an axial sectional view of the actuator. (A) is a side view which shows the core material expansion | extension process in the manufacturing method of the actuator. (B) is a perspective view which shows the stretch film winding process in the manufacturing method. It is an axial sectional view during voltage application of the actuator. (A) is a side view which shows the core material compression process in the manufacturing method of the actuator of 2nd embodiment of this invention. (B) is a perspective view which shows the stretch film winding process in the manufacturing method. It is an axial sectional view during voltage application of the actuator. It is an axial perpendicular direction sectional view of the actuator of a third embodiment of the present invention. It is an axial sectional view of an actuator of a fourth embodiment of the present invention. It is an axial sectional view during voltage application of the actuator.

Explanation of symbols

1: Actuator 2: Core material 3: Actuator element 30: Stretchable film 300: Dielectric film 301: Electrode 302: Insulating film 5: Actuator element 500: Dielectric film 501: Electrode 6: Hollow part 7: Valve a: Actuator b: Actuator Element b1: Dielectric film b2: Electrode c: Core material d1: Power source d2: Switch

Claims (13)

A rod-shaped core material that is elastically deformable in the axial direction, has almost no volume change due to elastic deformation, and has a side peripheral surface continuous in the axial direction;
A dielectric film made of a dielectric elastomer, and a plurality of electrodes arranged through the dielectric film, and is wound around the core material, and the voltage applied between the electrodes increases as the voltage increases A cylindrical actuator element in which a dielectric film extends, and
The actuator element is preliminarily attached to the core material that is elastically deformed in the axial direction.
In a state where the elastic restoring force of the core material and the restraining force of the actuator element on the core material are balanced, the core material is stopped,
By applying a voltage between the electrodes, the dielectric film is stretched, and the restraining force is reduced, whereby an elastic restoring force of the core material can be used to output a driving force in the axial direction. Actuator.   The actuator according to claim 1, wherein the core material is made of an elastomer.   The actuator element includes a stretchable film having the dielectric film, a pair of electrodes disposed on both surfaces of the dielectric film, and an insulating film disposed on one surface of the pair of electrodes. The actuator according to claim 1 or 2, wherein the actuator is wound around the core material in a spiral shape.   The actuator according to claim 1, wherein the actuator element is formed by alternately laminating the dielectric films and the electrodes around the core material. A cylindrical actuator element having a dielectric film made of a dielectric elastomer and a plurality of electrodes arranged through the dielectric film, and the dielectric film expands as the applied voltage between the electrodes increases When,
A hollow portion disposed in the shaft portion of the actuator element,
The hollow portion is filled with compressed gas,
An actuator that is deformed according to an expansion force of the compressed gas by increasing a voltage applied between the electrodes and extending the dielectric film.   The actuator element includes a stretch film having the dielectric film, a pair of electrodes disposed on both surfaces of the dielectric film, and an insulating film disposed on one surface of the pair of electrodes. The actuator according to claim 5, wherein the actuator is wound around the hollow portion in a spiral shape.   6. The actuator according to claim 5, wherein the actuator element is formed by alternately laminating the dielectric films and the electrodes around the hollow portion.   The actuator according to any one of claims 5 to 7, wherein the hollow portion is formed in a bag shape by the actuator element.   The actuator according to any one of claims 5 to 8, further comprising a shape retaining member for retaining the shape of the hollow portion.   The actuator according to claim 5, further comprising a valve capable of filling the hollow portion with the compressed gas.   The actuator according to any one of claims 1 to 10, wherein a maximum diameter in a direction perpendicular to the axis is less than 5 mm.   The actuator according to any one of claims 1 to 11, wherein the electrode is made of a mixture of an elastomer and a conductive material.   An actuator focusing body in which a plurality of the actuators according to any one of claims 1 to 12 are bundled.

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