JP2007252043A - Electrostatic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic actuator which can get stable driving force by enabling two pole plates to be installed at an equal interval. <P>SOLUTION: The pole plates 11 and 12 are made in the same spiral form, and are stuck together in double spiral form, using an insulating seal material 13, thus the pole plates 11 and 12 are insulated from each other, and at the same time the entire strength of the insulated electrostatic actuator 1 is improved, whereby it generates equal electrostatic force over the entire length by preventing the deformation due to deadweight of the electrostatic actuator 1 and minimizing the deformation of a lead L. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrostatic actuator driven by an electrostatic force.

Conventionally, there has been an electrostatic actuator that uses, as a driving force, an electrostatic force generated in both electrode plates when two insulated electrode plates are folded and stacked so as to overlap each other and a voltage is applied (for example, Non-Patent Document 1).
However, this actuator has a problem in that since the electrode plate is deformed by its own weight, the gap between the electrode plates gradually increases as it reaches the upper layer, so that the electrostatic force decreases and a stable driving force cannot be obtained. There is.
On the other hand, in order to stabilize the gap between the electrode plates, it is conceivable to improve the hardness of the electrode plates and maintain the shape of the electrode plates, but in this case, the expansion / contraction rate decreases due to the elastic force of the electrode plates themselves. However, there is a problem that the drive stroke is reduced.
“Electrostatic Actuator”, Tokyo Institute of Technology, Miyoshi Laboratory, [online], [Search February 7, 2006], Internet <URL http://www.ric.titech.ac.jp/saneken/actuater.html >

  The subject of this invention is providing the electrostatic actuator which can be installed so that the distance of the two electrode plates which opposes may become uniform, and can obtain the stable drive force.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to the Example of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention according to claim 1 is an electrostatic actuator that uses an electrostatic force generated when a voltage is applied to different conductive members as a driving force, and is formed in a spiral shape and expandable and contractable in a predetermined direction. 1 conductive member (11) and a second conductive member formed in a spiral shape, expandable and contractable in the predetermined direction, and alternately arranged in a double spiral shape with the first conductive member (11) (12) and an insulating member (13) disposed between the first (11) and the second conductive member (12) and insulating between the first (11) and the second conductive member (12) And an electrostatic actuator.

According to a second aspect of the present invention, in the electrostatic actuator according to the first aspect, the insulating member (13) is provided in close contact with the first (11) and the second conductive member (12). It is an electrostatic actuator characterized by this.
The invention according to claim 3 is the electrostatic actuator according to claim 1 or 2, wherein the insulating member (13) bonds the first (11) and the second conductive member (12), Is an electrostatic actuator.
According to a fourth aspect of the present invention, in the electrostatic actuator according to any one of the first to third aspects, the first (11) and the second conductive member (12) are formed in a spiral shape. It is an electrostatic actuator characterized by being a plate-shaped member.
According to a fifth aspect of the present invention, in the electrostatic actuator according to the fourth aspect, the first (11) and the second conductive member (12) have the same shape, and the insulating member (13) is layered. It is an electrostatic actuator characterized by being provided.
According to a sixth aspect of the present invention, in the electrostatic actuator according to any one of the first to fifth aspects, the outer edge portions of the first (11) and the second conductive member (12) are covered, It is an electrostatic actuator characterized by including the impact-absorbing member (30,130) which absorbs the impact from.
The invention according to claim 7 is the electrostatic actuator according to any one of claims 1 to 6, wherein the electrostatic actuator covers outer edge portions of the first (11) and the second conductive member (12), and Insulation protection members (30, 130) for insulating the first (11) and second conductive members (12) from the outside of the first (11) and second conductive members (12). It is an electrostatic actuator.
According to an eighth aspect of the present invention, in the electrostatic actuator according to any one of the first to seventh aspects, the direct current power source (41) to the first (11) and second conductive members (12). A voltage is applied, and the amount of expansion / contraction of the first (11) and second conductive member (12) is determined according to the amount of charge stored in the first (11) and second conductive member (12). It is an electrostatic actuator characterized by including a control part to control.

According to the present invention, the following effects can be obtained.
(1) In the present invention, the first and second conductive members are insulated and are arranged in a double spiral shape, and the electrostatic force between the first and second conductive members works continuously over the entire length. A large driving force can be obtained.

(2) In the present invention, since the insulating member is in close contact with the first and second conductive members, the first and second conductive members can be kept uniform. And a stable driving force can be obtained.

(3) In the present invention, since the insulating member bonds the first and second conductive members, the overall strength is improved, the deformation is caused by its own weight, and the distance between the first and second conductive members is increased. It is possible to prevent the change.

(4) In the present invention, since the first and second conductive members are plate-like members, they can be arranged so that the surfaces with large areas face each other, and an electrostatic force can be generated between the surfaces. Therefore, a large driving force can be obtained.

(5) In the present invention, since the insulating members are provided in layers, the first and second conductive members can be more securely bonded to further improve the overall strength, and at the same time, the first and second It is possible to completely insulate between the conductive members.

(6) Since this invention is provided with the impact-absorbing member which covers the outer edge part of the 1st and 2nd electroconductive member, this electrostatic actuator can be protected from an external impact.

(7) Since the present invention includes an insulating protective member that covers the outer edge portions of the first and second conductive members and insulates the first and second conductive members from the outside thereof, the conductive member is in contact with the outside. In this case, it is possible to prevent a short circuit between the first and second conductive members.

(8) In the present invention, the control unit applies a voltage from the DC power source to the first and second conductive members, and determines the amount of expansion and contraction of the first and second conductive members according to the amount of the stored charge. Since the control is performed, the amount of expansion / contraction does not change even when the application of voltage is stopped, and the driving can be performed with power saving.

  It is an object of the present invention to provide an electrostatic actuator that can be installed so that the distance between two electrode plates is uniform and can obtain a stable driving force. Are bonded in a double spiral shape using an insulating sealing material to insulate the two electrode plates and at the same time improve the strength of the entire insulated electrostatic actuator, thereby preventing deformation due to its own weight. This is achieved by minimizing lead changes and generating uniform electrostatic force over the entire length.

Hereinafter, the electrostatic actuator according to the first embodiment of the present invention will be described in more detail with reference to the drawings.
1A and 1B are front views of the electrode plates 11 and 12 (conductive members) of the electrostatic actuator 1 of this embodiment, and FIG. 1C is a front view of the electrostatic actuator 1. It is. FIG. 2 is a perspective view of a state in which the electrode plates 11 and 12 are combined. FIG. 3 is a longitudinal sectional view (sectional view taken along the line III-III in FIG. 2) taken along a plane passing through the spiral axis Z (predetermined axis) of the electrode plates 11 and 12.
As shown in FIG. 1 (c), the electrostatic actuator 1 includes an electrode plate 11 (first conductive member), an electrode plate 12 (second conductive member), terminals 21 and 22, and a sleeve 30. I have.
As shown in FIGS. 1A, 1B, and 2, the electrode plates 11 and 12 are spiral plate-like members formed of a conductive material (for example, phosphor bronze). is there. The strength of the electrode plates 11 and 12 is such a rigidity that the shape cannot be maintained by these single bodies (for example, the degree of deformation due to its own weight). The electrode plates 11 and 12 are formed so that the lead L (the distance traveled when the circuit moves once around the helical axis Z) has a certain length.

  As shown in FIGS. 1 (a) and 1 (c), the electrode plates 11 and 12 are combined by applying, for example, a silicon resin insulating seal material 13 (insulating member) to the upper surface of the electrode plate 11, It is performed by laminating the electrode plate 12 in a double spiral shape. Thereby, since the sealing material 13 is layered, the electrode plates 11 and 12 can be strongly bonded to each other by being in close contact with the surfaces of the electrode plates 11 and 12, and at the same time, the electrode plates 11 and 12 can be completely insulated. it can. In this way, since the electrodes 11 and 12 are bonded to each other over the entire length by the sealing material 13, the entire strength of the electrode plates 11 and 12 can be improved even if the strength is low. Even if the axis Z is arranged in the vertical direction, deformation due to its own weight can be prevented. Thereby, since the electrostatic actuator 1 can make the lead L uniform over the entire length, the distance between the opposing electrode plates 11 and 12 (refer to the opposing electrode plates 11A and 12A and electrode plates 11B and 12B shown in FIG. 3) can be reduced. The change can be reduced, and a uniform electrostatic force can be generated over the entire length.

Further, the electrode plates 11 and 12 are plate-like members, and the longitudinal cross-sectional shape thereof is such that the length d1 in the radial direction (arrow R direction) is the helical axis Z direction (helical axis Z) as shown in FIG. In the direction along the length d2). For this reason, when the electrode plates 11 and 12 are arranged, the surfaces 11a and 12a having large areas face each other. Thus, the electrode plates 11 and 12 can generate a large electrostatic force continuously over the entire length because the surfaces of the electrode plates 11 and 12 are opposed to each other at equal intervals over the entire length. Thus, the electrostatic actuator 1 can obtain a large driving force and a sufficient expansion / contraction amount.
The size of the electrode plates 11 and 12 varies depending on the application of the electrostatic actuator 1. As will be described later, the distance between the electrode plates only needs to be changed by the electrostatic force. For example, the diameter or the length in the direction of the helical axis is 1 mm or less to a large size of about 50 mm. .
The terminals 21 and 22 are members for connecting a cable connected to a DC power source 41 (described later) to the electrode plates 11 and 12, and are provided at terminal portions of the electrode plates 11 and 12.

  As shown in FIG. 1C, the sleeve 30 absorbs the impact when the electrostatic actuator 1 is impacted from the outside, and further, when the conductor comes into contact with the exterior, 12 is a member for preventing a short circuit (in the figure, the sleeve 30 is shown in cross section). The sleeve 30 is a cylindrical member whose central axis is coaxial with the helical axis Z, and the inner diameter thereof is substantially equal to the diameter of the electrode plates 11 and 12, and the outer edge portions of the electrode plates 11 and 12 are formed on the inner peripheral surface thereof. It is fixed using an adhesive 31. The sleeve 30 has an insulating property and is formed of a flexible elastic body (for example, a polymer material such as silicon rubber). Thereby, the sleeve 30 functions as an insulation protection member for preventing the electrode plates 11 and 12 from being short-circuited when a conductor contacts from the outside, and when the electrostatic actuator 1 is impacted from the outside. Moreover, it functions as an impact absorbing member that absorbs this impact. The flexibility of the sleeve 30 is sufficient so as not to hinder the expansion and contraction of the electrode plates 11 and 12.

Next, the operation of the electrostatic actuator 1 will be described.
4A and 4B are diagrams illustrating the operation of the electrostatic actuator 1 according to the present embodiment. FIG. 4A is a standard state, FIG. 4B is a contracted state, and FIG. FIG.
As shown in FIG. 4A, in the electrostatic actuator 1, in the state where the terminals 21 and 22 are short-circuited by the cable 41 and connected to the Gnd, the electrode plates 11 and 12 have the same potential, and the electrode plates 11 and 12 are in the same potential. Since the electrostatic force does not work in the meantime, the lead L is kept in a standard state.

  As shown in FIG. 4B, when the terminal 21 is electrically connected to the negative terminal of the DC power supply 41, negative charges are stored in the electrode plate 11, while the terminal 22 is connected to the DC power supply 41. When electrically connected to the positive terminal, positive charge is stored in the electrode plate 12. And as shown in FIG. 3, the attractive force F by an electrostatic force generate | occur | produces between the electrode plates 11 and 12 which oppose, the distance between the electrode plates 11 and 12 becomes small, and the electrode plates 11 and 12 have the full length. Get smaller. Since the lead L is equal over the entire length, the attractive force F is equal over the entire length of the electrostatic actuator 1. Thereby, the electrostatic actuator 1 can obtain a stable driving force.

As shown in FIG. 4B, when the electrode plates 11 and 12 are contracted, the electrostatic actuator 1 is contracted and the length in the spiral axis Z direction is shortened. Since the sleeve 30 has sufficient flexibility, the sleeve 30 is deformed into a wave shape and contracts following the outer edge portions of the electrode plates 11 and 12. Thereby, the electrostatic actuator 1 can ensure a sufficient amount of shrinkage.
Even when the polarity of the electrode is reversed and a positive charge is stored in the electrode plate 11 and a negative charge is stored in the electrode plate 12, an attractive force acts between the electrode plates 11 and 12 in the same manner. The actuator 1 can be contracted.

As shown in FIG. 4 (c), when the terminals 21 and 22 are electrically connected to the negative terminal of the DC power supply 41, the electrostatic actuator 1 stores negative charges on the electrode plates 11 and 12, A repulsive force is generated between the electrode plates 11 and 12 by the electrostatic force, and the electrode plates 11 and 12 extend. Along with this, the electrostatic actuator 1 expands and the length in the spiral axis Z direction becomes longer. Since the sleeve 30 has flexibility, it extends following the outer edges of the electrode plates 11 and 12. Thereby, the electrostatic actuator 1 can ensure sufficient elongation.
At this time, the electrostatic actuator 1 can obtain a stable driving force because the repulsive force generated in the electrode plates 11 and 12 is equal over the entire length, as in the case of contraction.

  Further, since the electrostatic actuator 1 is voltage driven and consumes little current, it can be driven with power saving. Furthermore, a control unit (not shown) for controlling the voltage applied to the electrode plates 11 and 12 from the DC power supply 41 is provided, and the electrode plates 11 and 12 are selected according to the amount of charge stored in the electrode plates 11 and 12. The amount of expansion / contraction may be controlled. Since the electrostatic force has the property that it works as long as electric charges are stored in the electrode plates, even if this control unit stops applying voltage according to the amount of electric charges stored in the electrode plates 11 and 12. The expansion and contraction amounts of the electrode plates 11 and 12 do not change and can be driven with further power saving.

  The driving stroke of the electrostatic actuator 1 is, for example, about 0.01 N when the spirals of the electrode plates 11 and 12 have an inner diameter of 10 mm, an outer diameter of 50 mm, a total length of 3 mm, and three turns, and an applied voltage of 500V.

As described above, the electrostatic actuator 1 according to the present embodiment includes the electrode plate 11 (first conductive member) and the electrode plate 12 (second conductive member) formed in the same spiral shape. The insulating sealing material 13 (insulating member) is arranged in a spiral shape, and is in close contact with the electrode plates 11 and 12 to strongly bond the electrode plates 11 and 12. As a result, the electrostatic actuator 1 can improve the overall strength and prevent the distance between the opposing electrode plates 11 and 12 from changing due to its own weight, etc., thereby generating a stable electrostatic force and a stable driving force. Can be obtained.
Further, the electrostatic actuator 1 is arranged so that the surfaces of the electrode plates 11 and 12 having large areas face each other, and can generate an electrostatic force continuously across the entire length between the surfaces. A sufficient amount of expansion and contraction can be obtained.

Next, a second embodiment of the electrostatic actuator to which the present invention is applied will be described.
The electrostatic actuator 101 according to the second embodiment is for driving a robot arm.
In the following description, parts having the same functions as those of the above-described first embodiment are denoted by the same reference numerals, and redundant description is omitted as appropriate.
FIG. 5 is a diagram showing the electrostatic actuator 101 of this embodiment and the robot 100 to which the electrostatic actuator 101 is attached.
As shown in FIG. 5, in the robot 100, a first arm 103 is fixed to a base 102, and a second arm 104 is provided at the tip of the first arm 103 so as to be rotatable about an axis X. . One end of the second arm 104 is provided with a hand 105 for gripping an object. The total length of the first arm 103 and the second arm 104 is about 300 mm.

  The electrostatic actuator 101 contains a pole plate similar to that of the first embodiment in a sleeve 130, and is arranged such that the helical axis Z2 is in the longitudinal direction of the first arm 103. In addition, the electrostatic actuator 101 is provided with rods 131 and 132 at both ends of the sleeve 130. The axial directions of the rods 131 and 132 are coaxial with the helical axis Z2. The distal end of the rod 131 is rotatably connected to the base portion 102, and the distal end of the rod 132 is rotatably connected to an attachment hole 104 a provided on the side opposite to the hand 105 of the second arm 104. The total length of the electrostatic actuator 101 is about 200 mm.

Operations of the robot 100 and the electrostatic actuator 101 will be described.
When a voltage is supplied to the electrode plate in the sleeve 130 from a power source (not shown) as in the first embodiment, the electrostatic actuator 101 expands and contracts in the direction of the helical axis (see arrow Z3), and the rods 131 and 132 Move in the direction of the helical axis. At the same time, the second arm 104 of the robot 100 can rotate about the axis X in the direction of the arrow θ2.

  As described above, the electrostatic actuator 101 according to this embodiment can rotationally drive the second arm 104 of the robot 100 about the axis X. That is, the electrostatic actuator 101 can be used as a drive source for driving the machine.

It is a front view of Example 1 of an electrostatic actuator and an electrode plate according to the present invention. It is a perspective view of the state which combined the electrode plate of Example 1. FIG. 1 is a longitudinal sectional view of an electrode plate of Example 1. FIG. It is a figure which shows operation | movement of the electrostatic actuator of Example 1. FIG. It is a figure which shows the robot which attached Example 2 of the electrostatic actuator by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Electrostatic actuator 11, 12 Electrode plate 13 Insulating seal material 21, 22 Terminal 30, 130 Sleeve 100 Robot 103 First arm 104 Second arm 131, 132 Rod L Lead Z, Z2 Spiral shaft

Claims (8)

An electrostatic actuator that uses an electrostatic force generated when a voltage is applied to different conductive members as a driving force,
A first conductive member formed in a spiral shape and capable of expanding and contracting in a predetermined direction;
A second conductive member that is formed in a spiral shape, is extendable in the predetermined direction, and is arranged in a double spiral shape alternately with the first conductive member;
An insulating member disposed between the first and second conductive members and insulating between the first and second conductive members;
Electrostatic actuator with The electrostatic actuator according to claim 1,
The insulating member is provided in close contact with the first and second conductive members;
An electrostatic actuator characterized by The electrostatic actuator according to claim 1 or 2,
The insulating member is to bond the first and second conductive members;
An electrostatic actuator characterized by In the electrostatic actuator according to any one of claims 1 to 3,
The first and second conductive members are plate-like members formed in a spiral shape,
An electrostatic actuator characterized by The electrostatic actuator according to claim 4, wherein
The first and second conductive members have the same shape,
The insulating member is provided in layers;
An electrostatic actuator characterized by In the electrostatic actuator according to any one of claims 1 to 5,
Comprising an impact absorbing member that covers outer edges of the first and second conductive members and absorbs external impacts;
An electrostatic actuator characterized by In the electrostatic actuator according to any one of claims 1 to 6,
An insulating protective member that covers outer edges of the first and second conductive members and insulates the first and second conductive members from the outside of the first and second conductive members;
An electrostatic actuator characterized by The electrostatic actuator according to any one of claims 1 to 7,
A voltage is applied to the first and second conductive members from a DC power source, and the amount of expansion and contraction of the first and second conductive members depends on the amount of charge stored in the first and second conductive members. A control unit for controlling
An electrostatic actuator characterized by

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