JPWO2009028313A1 - Electrostatic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic electrostatic actuator capable of obtaining a sufficient stroke (displacement amount) with a simple and inexpensive configuration without increasing the overall thickness. When a predetermined voltage is applied between a pair of counter electrodes 11, a distance d between the counter electrodes is narrowed by an electrostatic attractive force generated between the electrodes. At this time, since one counter electrode 11 pressurizes one end portion 21 of the actuator 20, the actuator 20 can be rotated to a rising posture in the upper part of the figure. A simple and inexpensive configuration using the lever principle makes it possible to obtain a sufficient amount of displacement without increasing the thickness of the entire actuator. [Selection] Figure 1

Description

  The present invention relates to an electrostatic actuator using an elastic elastomer as a dielectric, which is positioned as one of electroactive polymers (EAP: Electro Active Polymer), and particularly capable of obtaining a large displacement in the vertical direction. About.

  A parallel plate type electrostatic actuator element can be displaced in a direction perpendicular to the electrodes when energized.

  Patent Document 1 listed below describes an electrostatic actuator belonging to a parallel plate type in which a ribbon-like electrode film is alternately stacked in a plurality of stages in the thickness direction to form a sandwich structure.

In this electrostatic actuator, when a potential difference is applied between the first electrode and the second electrode facing each other in the plate thickness direction, electrostatic attraction acts between these electrodes in a direction in which the distance between the opposing electrodes is reduced. Displace. The integrated value of the contraction displacement amount of the distance between the counter electrodes is the displacement amount (stroke) of the entire electrostatic actuator.
JP 2001-268948 A

  However, the stroke (displacement) in the thickness direction of such an actuator does not exceed the thickness dimension of the actuator due to the driving principle, and in order to obtain the stroke in the thickness direction, the entire actuator becomes thicker, resulting in a thinner or smaller size. There was a problem that it was difficult to convert.

  Further, in order to obtain a stroke in the thickness direction, if the distance between the counter electrodes constituting the actuator is increased, a high driving voltage is required. However, the increase in the drive voltage leads to a high circuit cost due to a circuit load including wiring such as withstand voltage, charging, and safety measures. Furthermore, there arises a problem that the design is restricted by securing the insulation property of the elastic elastomer itself disposed between the electrodes or by the withstand voltage limit.

  The present invention is for solving the above-described conventional problems, and an electrostatic actuator that can obtain a sufficient stroke (displacement amount) with a simple and inexpensive configuration without increasing the thickness of the entire actuator. It is intended to provide.

  Another object of the present invention is to provide an electrostatic actuator that can ensure a stroke in the thickness direction without increasing the driving voltage.

  An electrostatic actuator according to the present invention includes an elastic elastomer and a pair of electrodes disposed on both sides of the elastic elastomer, and is driven by an electrostatic force acting between the pair of electrodes, and is connected to the driving unit. And an actuator for amplifying the stroke of the drive unit.

  In the present invention, a thin electrostatic actuator that does not increase the overall thickness dimension can be obtained by a simple and inexpensive configuration using the principle of an insulator.

  In the above, the operating element constitutes an insulator, and one end of the operating element that is on the power point side of the insulator is provided between the pair of electrodes of the driving unit, and the operating side that is on the operating point side of the insulator The other end of the child is provided outside the drive unit.

With the above means, a large amount of displacement can be obtained even if it is thin.
In the above, it is preferable that the operating element is formed in an arc shape and the driving force of the driving unit is transmitted to one end of the arc.

  In the above means, the arm length of the actuator does not become longer than necessary. For this reason, an electrostatic actuator can be reduced in size.

  In addition, it is preferable that the one electrode and one end of the actuator are connected via a hinge or a connecting tape.

  In the above means, the connection state between the electrode and the actuator during operation can be stabilized, and the actuator can be reliably operated.

  The actuator is preferably formed of an insulating material, and more preferably, a part of the actuator is located inside the driving unit, and the electrodes are in contact with each other when the driving unit is driven. Insulation maintaining part for preventing

  In the above means, since an actuator can always be interposed between one electrode and the other electrode, even if the distance between the electrodes is reduced by electrostatic attraction, insulation between them can be ensured. It is possible to reliably prevent the occurrence of a short circuit.

Furthermore, the thing provided with two or more said operation elements is preferable.
Even with the above-described configuration, the insulation can be enhanced and the occurrence of a short circuit can be prevented. In addition, a driving object can be placed on each actuator, and for example, it can be moved up and down while maintaining the horizontal posture of the driving object.

In addition, the driving units may be stacked in multiple stages, and the actuator may be provided between an electrode forming the lower layer side driving unit and an electrode forming the upper layer side driving unit.
In the above means, the actuator can be stably driven with a larger driving force.

  In the present invention, a sufficient amount of displacement can be obtained with a simple and inexpensive configuration without increasing the thickness of the entire electrostatic actuator.

  In addition, according to the present invention, it is possible to reduce the cost by eliminating various problems of insulation by preventing the drive voltage from being increased.

  FIG. 1 is a cross-sectional view of an electrostatic actuator showing a first embodiment of the present invention, where (A) shows an initial state before operation (lie down), and (B) shows an operation state (rise posture). Yes.

  As shown in FIG. 1A, an electrostatic actuator 1 according to an embodiment of the present invention has parallel plate type counter electrodes 11 and 12, and an elastic elastomer 14 is provided between the pair of counter electrodes. In addition, the laminate has a three-layer structure. A laminate including the one counter electrode 11, the other counter electrode 12, and an elastic elastomer 14 provided therebetween constitutes a drive unit 10 of the electrostatic actuator 1.

  The elastic elastomer 14 can be constituted by a semi-fluid member having elasticity such as silicone gel, or can be constituted by sealing the fluid member with a bag. In any case, in order to maintain the withstand voltage between the pair of counter electrodes 11, 12, the semi-fluid member or the fluid member is preferably made of a material having a high insulation rate.

  An actuator 20 is provided between the one counter electrode 11 and the other counter electrode 12. The operating element 20 is made of an insulating material such as acrylic or plastic. The shape of the actuator 20 is close to a rod shape or a plate shape, but its cross-sectional shape is not an L shape or a linear shape, but a curled shape that is slightly arcuate. For this reason, the length of the arm portion of the actuator 20 does not become longer than necessary, and in this respect, it is possible to make it suitable for downsizing.

  The actuator 20 is driven using a lever principle. In other words, the actuator 20 has a power point at one end 21 facing the counter electrodes 11 and 12 and has an action point at the other end 22 protruding outward from the counter electrodes 11 and 12. A portion in contact with the other counter electrode 12 is a fulcrum 23. In the initial state shown in FIG. 1 (A), the operating element 20 is provided in such a posture as to lie down along the horizontal direction.

  The actuator 20 is preferably configured such that the fulcrum side is rotatably supported with respect to the other counter electrode 12. The actuator 20 may be bent into a substantially “<” shape. In this case, the bent portion serves as the fulcrum 23.

  One counter electrode 11 and the other counter electrode 12 forming the drive unit 10 are connected to a power source, and a predetermined drive voltage is applied between the two electrodes when energized. .

  When a predetermined drive voltage is applied in an energized state, an electrostatic attractive force is generated between the counter electrodes 11 and 12, and the distance d between the counter electrodes is displaced in a direction in which the counter electrode is compressed against the elastic force of the elastic elastomer. Be made. At this time, the elastic elastomer is displaced in a direction in which the area increases (horizontal direction intersecting the compression direction) (flat state).

  In the process of reducing the distance d between the counter electrodes, the one counter electrode 11 pressurizes the one end 21 on the power point side of the actuator 20 in the Z2 direction in the drawing. As a result, the actuator 20 rotates counterclockwise in the figure around the fulcrum 23, so that the other end 22 on the action point side can be lifted in the Z1 direction in the figure. In other words, the entire actuator 20 can be set in the rising posture, and the rising posture can be maintained as long as the drive voltage is continuously applied.

  At this time, in the drive unit 10, the actuator 20 can be operated largely only by moving the counter electrode 11 toward the counter electrode 12 by a slight stroke amount. In this respect, the actuator 20 has an amplifying function for increasing the stroke amount when the drive unit 10 is driven.

  Thus, in the electrostatic actuator 1 of the present invention, by using the lever principle, a large stroke amount (displacement amount) can be obtained even if the driving unit 10 made of a laminated body is not stacked in the plate thickness direction, that is, it remains thin. Obtainable. However, as will be described later, this does not deny a configuration in which the driving unit 10 is stacked in the thickness direction in order to obtain a larger driving force.

  In the operating state shown in FIG. 1B, one end 21 of the actuator 20 is always interposed between the counter electrode 11 and the counter electrode 12. For this reason, it is possible to avoid electrical contact (short circuit) between the counter electrode 11 and the counter electrode 12. That is, the insulation between the counter electrode 11 and the counter electrode 12 can be maintained.

Next, a second embodiment and a third embodiment of the present invention will be described.
2A and 2B are cross-sectional views of the electrostatic actuator showing the second embodiment, in which FIG. 2A shows an initial state before operation (lie down), and FIG. 2B shows an operation state (rise posture). 3A and 3B are cross-sectional views of the electrostatic actuator showing the third embodiment, in which FIG. 3A shows an initial state (sitting posture) before operation, and FIG. 3B shows an operating state (rise posture).

  The electrostatic actuator 2 shown as the second embodiment in FIG. 2A also has a drive unit 10 composed of an elastic elastomer 14 and the pair of counter electrodes 11 and 12 disposed opposite to each other.

  Further, the electrostatic actuator 2 is provided with a hinge 35 at the end of the one counter electrode 11. One end 31 of the operating element 30 is pivotally attached to the hinge 35. The cross section of the actuator 30 in this embodiment has an arc shape, and the outer surface side of the arc shape is placed on the other counter electrode 12. In this embodiment, the hinge 35 on one end portion 31 side functions stably as a power point of the insulator, and the other end portion 32 functions as an action point. The outer surface of the arc of the actuator 30 acts as a fulcrum for the lever.

  As shown in FIG. 2B, when a predetermined voltage is applied between the counter electrodes 11 and 12, the distance between the electrodes is reduced as described above. At this time, the hinge 35 is brought close to the other counter electrode 12 together with the one counter electrode 11. For this reason, the operating element 30 rolls on the surface of the other counter electrode 12 with an arcuate outer surface as a fulcrum, and is rotated counterclockwise in the figure. Therefore, also in this electrostatic actuator 2, it can be set to the standup | rising attitude | position which can lift the other edge part 32 to Z1 direction similarly to the above.

  Further, the electrostatic actuator 3 shown as the third embodiment in FIG. 3A is different in that an actuator 40 having a substantially “<” shape is provided in place of the arc-shaped actuator 30. ing.

  In the operating element 40, one end 41 of the operating element 40 on the power point side is connected to one counter electrode 11 via a hinge 35. The operating element 40 is attached with the other end 42 and the bent part 43 facing the other counter electrode 12. In the initial state, the bent portion 43 may be in contact with the other counter electrode 12 or may be separated, but at least until the lowering operation of the one counter electrode 11 is completed, The bent portion 43 is in contact with the other counter electrode 12.

  Also in the third embodiment, when a predetermined drive voltage is applied between the counter electrodes 11 and 12 to reduce the distance between the counter electrodes, the hinge 35 approaches the other counter electrode 12 together with the one counter electrode 11. As a result, the actuator 40 is rotated counterclockwise with the bent portion 43 as a fulcrum. Therefore, in this electrostatic actuator 3 as well, the other end 42 of the actuator 40 can be lifted in the Z1 direction in the drawing.

  Also in the second and third embodiments, the actuator 20 can be operated largely only by moving the counter electrode 11 constituting the drive unit 10 to the counter electrode 12 side by a slight stroke amount. 30 has an amplifying function for increasing the stroke amount when the drive unit 10 is driven.

  4A and 4B are cross-sectional views of an electrostatic actuator showing a fourth embodiment of the present invention. FIG. 4A shows an initial state before operation (lie down), and FIG. 4B shows an operation state (rise posture). Yes.

  The electrostatic actuator 4 shown as the fourth embodiment is different from the above embodiments in that a plurality of actuators 50 having a substantially S-shaped cross section are provided.

  In the actuator 50, one end 51 on the power point side is formed with a small radius of curvature (large curvature), and the other end 52 on the side of the operating point is formed with a large radius of curvature (small curvature). .

  In the initial state shown in FIG. 4A, the actuator 50 is in a lying posture, and the one end 51 side is in contact with the lower surface of one counter electrode 11.

  In addition, the elastic elastomer 14 provided between one counter electrode 11 and the other counter electrode 12 is in an uncompressed natural state.

  When the electrostatic actuator 4 in the initial state is set in an energized state and a predetermined drive voltage is applied between the pair of counter electrodes 11 and 12, the distance between the electrodes is reduced according to the electrostatic attractive force generated between the electrodes, The one end 51, 51 side is pressed downward (Z2 direction). As a result, the actuators 50 and 50 are rotated so that the other end portions 52 and 52 are lifted upward in the drawing. Therefore, in this electrostatic actuator 4 as well, it is possible to set the operating element 50 in the rising posture as described above, and a large displacement can be obtained at this time. In this respect, the actuator 50 has an amplifying function for increasing the stroke amount when the drive unit 10 is driven.

  Further, as shown in FIG. 4B, at one end of the actuator 50, 50 formed of an insulating material between one counter electrode 11 and the other counter electrode 12 at both ends of the drive unit 10 at all times. It becomes possible to interpose the parts 51 and 51, respectively. Therefore, it is possible to always form a constant gap between one counter electrode 11 and the other counter electrode 12, and it is possible to reliably prevent dielectric breakdown and short circuit between them. That is, one end 51 on the power point side constitutes an insulation maintaining portion that prevents a short circuit between one counter electrode 11 and the other counter electrode 12.

FIG. 5 is a sectional view of an electrostatic actuator showing a fifth embodiment of the present invention.
The electrostatic actuator 5 shown in FIG. 5 is different in that the drive unit 10 is formed as a multi-stage stacked body stacked in two stages. That is, in the electrostatic actuator 5, the driving unit 10 includes the first elastic elastomer 14 </ b> A between the counter electrode 11 and the counter electrode 12, and the first elastic elastomer between the counter electrode 12 and the counter electrode 13. 14B. One end 21 of the actuator 20 is disposed so as to face the end of the counter electrode 11 provided at the uppermost stage, and the fulcrum is set to the counter electrode 13 located at the lowermost stage. The one end 21 of the actuator 20 and the uppermost counter electrode 11 are connected by using an adhesive tape T or the like.

  The switch SW is controlled so that a voltage e can be applied between the counter electrode 11 and the counter electrode 12 and between the counter electrode 12 and the counter electrode 13. When the switch SW is set in an energized state, a drive voltage e is applied between the electrodes constituting the drive unit 10. At this time, the interelectrode distance between the counter electrode 11 and the counter electrode 12 and the interelectrode distance between the counter electrode 12 and the counter electrode 13 are each compressed and deformed in a narrowing direction.

  Thus, when the drive part 10 is comprised in multiple stages, a drive force can be generated in each of a pair of opposing counter electrode. For this reason, it is possible to drive the actuator 20 in the Z1 direction in the drawing with a greater force, and it is possible to increase the stroke, and therefore the stroke after amplification by the actuator can be further increased.

Although this embodiment has been described using the same actuator 20 as in the first embodiment, a configuration using the actuator shown in other embodiments may be used.
In addition, the driving unit 10 may have a multi-stage configuration of three or more stages.

FIG. 6 is a perspective view of an electrostatic actuator showing a sixth embodiment of the present invention.
The electrostatic actuator 6 shown in FIG. 6 is provided with a plurality of actuators 20 (shown with 20A, 20B, 20C, and 20D individually) around one drive unit 10 in each of the above embodiments. It is different from the form.

  In this embodiment, when a predetermined voltage is applied between one counter electrode 11 and the other counter electrode 12 forming the drive unit 10 and the distance between these electrodes is reduced, a plurality of actuators 20A, 20B, 20C and 20D can be driven simultaneously. For this reason, by placing a driving object on each actuator, the driving object can be moved up and down in a vertical direction while maintaining a horizontal posture.

  In addition, one end portion (end portion on the power point side) 21 of each of the actuators 20A, 20B, 20C, and 20D is sandwiched between each of the four edge portions where one counter electrode 11 and the other counter electrode 12 face each other. It is possible. For this reason, the withstand voltage between one counter electrode 11 and the other counter electrode 12 can be increased, and the occurrence of a short circuit can be reliably prevented.

  7A and 7B are cross-sectional views of an electrostatic actuator showing a seventh embodiment of the present invention, in which FIG. 7A shows an initial state before operation (lie down), and FIG. 7B shows an operation state (rise posture). ing.

  As shown in FIG. 7A, the electrostatic actuator 7 shown in the seventh embodiment is different from the above embodiments in that the actuator 60 is provided on the other counter electrode 12. Yes. The configuration of the drive unit 10 is the same as that in the first to fifth embodiments. Alternatively, the same configuration as that of the sixth embodiment may be used.

  The operating element 60 has a bent portion 63 formed by bending a part thereof into a substantially U shape at one end portion 61 on the power point side, and the other end portion 62 is opposed to the one end. It is arranged on the surface side of the electrode 11. In the operating element 60, one end 61 bent in the substantially U shape is fixed to the other counter electrode 12 by using an adhesive tape T or the like so as to be rotatable.

  As shown in FIG. 7B, when a predetermined voltage is applied between the pair of counter electrodes 11 and 12, the distance d between the counter electrodes is narrowed. At this time, the end of the counter electrode 11 pressurizes the one end 61 downward (Z2 direction). As a result, the actuator 60 is rotated in the clockwise direction with the bent portion 63 as a fulcrum, and the other end 62 is lifted. Thereby, also in this electrostatic actuator 7, it is possible to displace the actuator 60 with a big displacement amount with respect to Z1 direction of illustration. In this respect, the actuator 60 has an amplifying function for increasing the stroke amount when the driving unit 10 is driven.

  In each of the above-described embodiments, the case where the actuator is displaced in the illustrated Z1 direction has been described. However, the present invention is not limited to this, and the displacement direction may be the illustrated Z2 direction. In the first to sixth embodiments, in order to displace the actuator in the Z2 direction, one end portion of each actuator serving as a power point may be connected to the other counter electrode 12 side. In the seventh embodiment, one end 61 of the actuator 60 may be connected to one counter electrode 11 side. That is, each actuator can be oriented in the direction of displacement by the counter electrode to be connected.

It is sectional drawing of the electrostatic actuator which shows the 1st Embodiment of this invention, (A) is the initial state before operation (lie-down posture), (B) is an operation state (rise posture), It is sectional drawing of the electrostatic actuator which shows 2nd Embodiment, (A) is the initial state before operation (lie-down posture), (B) is an operation state (rise posture), It is sectional drawing of the electrostatic actuator which shows 3rd Embodiment, (A) is the initial state before operation (lie-down posture), (B) is an operation state (rise posture), It is sectional drawing of the electrostatic actuator which shows 4th Embodiment, (A) is the initial state (sleeping posture) before operation | movement, (B) is an operation state (rise posture), Sectional drawing of the electrostatic actuator which shows 5th Embodiment, The perspective view of the electrostatic actuator which shows 6th Embodiment, It is sectional drawing of the electrostatic actuator which shows 7th Embodiment, (A) is the initial state (lie-down position) before operation | movement, (B) is an operation state (rise posture),

Explanation of symbols

1, 2, 3, 4, 5, 6, 7 Electrostatic actuator 10 Driving unit 11 One counter electrode 12 The other counter electrode 13 The counter electrode 14 Elastic elastomer 20, 30, 40, 50, 60 Actuators 21, 31, 41, 51, 61 One end portion 22, 32, 42, 52, 62 on the force point side The other end portion 43 on the action point side, bent portion

Claims (9)

An elastic elastomer and a pair of electrodes disposed on both sides of the elastic elastomer and a drive unit driven according to an electrostatic force acting between the pair of electrodes, and connected to the drive unit, the stroke of the drive unit An electrostatic actuator comprising: an amplifying actuator. The operating element constitutes an insulator, and one end of the operating element on the lever side of the lever is provided between the pair of electrodes of the drive unit, and the other end of the operating element on the operating point side of the lever The electrostatic actuator according to claim 1, wherein is provided outside the drive unit. The electrostatic actuator according to claim 1, wherein the actuator is formed in an arc shape, and a driving force of the driving unit is transmitted to one end of the arc. The electrostatic actuator according to claim 1, wherein the one electrode and one end of the actuator are coupled via a hinge or a connecting tape. The electrostatic actuator according to claim 1, wherein the actuator is made of an insulating material. The electrostatic actuator according to claim 1, wherein a part of the operating element is located inside the driving unit, and is an insulation maintaining unit that prevents the electrodes from contacting each other when the driving unit is driven. The electrostatic actuator according to claim 1, wherein a plurality of the actuators are provided. 2. The electrostatic actuator according to claim 1, wherein the driving unit is stacked in multiple stages, and the actuator is provided between an electrode forming a lower layer side driving unit and an electrode forming an upper layer side driving unit. . The electrostatic actuator according to claim 1, wherein the elastic elastomer is of a gel type enclosed in a bag.

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