JP3006178B2 - Electrostatic actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic actuator which obtains a driving force by utilizing an unbalance of electric field strength.

[0002]

2. Description of the Related Art FIG. 13 shows a conventional example of this kind. This is because a comb-shaped fixed electrode F and a movable electrode M are meshed with each other with an appropriate gap provided, and a voltage is applied to both, thereby displacing in the longitudinal direction of the comb teeth, and is proportional to the number of comb teeth. This is to obtain an electrostatic driving force. When a voltage is applied as shown in the figure, the displacement is made in the direction of arrow R1, and when a voltage is applied as shown in the figure, the displacement is made in the direction of arrow R2. Note that H
Indicates a support portion (fixed portion). If the electrostatic driving force F acting in this case is ε as the relative permittivity, d as the gap distance, n as the number of comb teeth, t as the tooth thickness, and V as the applied voltage, F = ε · n · t · Expressed as V ² / 2d. FIG. 14 shows another conventional example. In this method, a fixed electrode F and a movable electrode M are arranged to face each other, and a voltage is applied to both of them to obtain an electrostatic driving force in the direction of reducing the gap as indicated by arrow F. The electrostatic driving force F in this case is expressed as F = ε · S · V ² / 2d ^{2 where} ε is the relative dielectric constant, d is the gap distance, S is the facing area, and V is the applied voltage.

[0003]

The latter method is in inverse proportion to the square of the distance d between the gaps. Therefore, if the gap is set large so as to increase the displacement, there is a problem that a driving force cannot be obtained. On the other hand, the former can increase the amount of displacement as compared with the latter, but there is a limit in the number of comb teeth that can be manufactured, the distance between the gaps, the tooth thickness, and the like. As a result, there is a problem that a large driving force cannot be obtained. . Therefore, an object of the present invention is to enable a large driving force and a large displacement to be generated.

[0004]

Means for Solving the Problems In order to solve such problems, in the first invention, a plurality of comb-shaped fixed electrodes are provided.
Fixing members arranged in a row and on the front and back of the insulator
Each is formed, the first comb-like meshing with comb teeth of the fixed electrode, the second movable electrode, and a movable member having in accordance with the number of the fixed electrode, the guide for guiding the movable member primarily in one direction A voltage of a first polarity to one of the movable electrodes via the guide member, and the other movable electrode
And the fixed electrode applies a second polarity voltage, respectively,
It is characterized in that the movable member is driven in one direction. According to a second aspect, in the first aspect, the first,
Either one of the second movable electrodes and the insulator are used as a dielectric.
The voltage of the first polarity is applied to the remaining movable electrodes,
A voltage of the second polarity is applied to the dielectric and the fixed electrode, respectively.
It is characterized by adding . In the third invention,
In the first or second aspect, wherein at least the movable member with respect to the fixed member are laminated toward the direction of movement two or more, it is characterized by achieving increase in the driving force. According to a fourth aspect of the present invention, in any one of the first to third aspects, the guide member is an elastic support spring. Further, in the fifth invention, the first to third embodiments
The invention is characterized in that the guide member is constituted by comb teeth of a fixed electrode and a guide rail.

In a sixth invention, a cylindrical fixed electrode,
It is provided so as to be movable inside this fixed electrode, and its cross section is almost
First and second movable electrodes, the first, the circular second movable electrodes which are respectively formed surface sandwiching the insulator circular, the rear surface
A guide member for guiding along the central axis direction of the cylindrical fixed electrode, a voltage of the first polarity is applied to one of the movable electrodes via the guide member, and the remaining movable electrode and the fixed
A voltage of a second polarity is applied to each of the electrodes,
It is characterized in that the material is driven in one direction. In a seventh aspect based on the sixth aspect, the first and second movable electrodes are provided.
Is replaced with a dielectric, and the remaining
A voltage of a first polarity is applied to the movable electrode,
It is characterized in that a voltage of the second polarity is applied to each of the fixed electrodes . Further, in the eighth invention, a plurality of comb-shaped
Two fixed electrodes are arranged in a row, facing each other at a predetermined interval.
A stator, and to mate with the comb teeth of the fixed electrode, the first to fourth movable electrode, each insulated from one another via an insulator, low <br/> with in accordance with the number of the fixed electrode And a first rotating electrode formed at each end of the shaft of the rotor and connected to the first and third movable electrodes, and a second rotating electrode connected to the second and fourth movable electrodes. An electrode, and first and second brushes for pressing and fixing the rotor to a stator via the first and second rotating electrodes ,
A voltage of the first polarity is applied between the first brush and the stator.
And a second polarity between the second brush and the stator.
By applying a voltage, and wherein the <br/> letting rotate the rotor.

According to a ninth invention, in the eighth invention,
The insulator and the first, third movable electrode or the insulator and the second, replaces the fourth movable electrode to the dielectric, the rest of the variable
A voltage of the first polarity is applied to the moving electrode by the dielectric and the fixed electrode.
It is characterized in that a voltage of the second polarity is applied to each pole . In the tenth invention, the first and second disks are formed by cutting out a disc and insulated from each other via an insulator.
A rotor having a movable electrode; and a pair of stators for rotatably sandwiching and supporting the rotor. A voltage of a first polarity is applied from a shaft support of the stator to a second movable electrode.
Is supplied to the first movable electrode and the pair of stators.
It is characterized in that the rotor is rotated by supplying a bipolar voltage. Further, in the eleventh invention, one of the insulator and the movable electrode is placed on a dielectric.
The voltage of the first polarity is applied to the remaining movable electrodes.
A voltage of the second polarity is applied to the electric body and the fixed electrode, respectively.
It is characterized in that.

[0007]

A pair of comb-shaped movable electrodes insulated from each other are arranged so as to mesh with each other with respect to the comb-shaped fixed electrode, and a voltage is applied between one of the movable electrodes and the fixed electrode and the remaining movable electrode. Is applied, a large driving force can be generated, and the displacement amount is increased. Further, instead of a pair of movable electrodes, the movable electrode may be composed of an electrode and a dielectric.

[0008]

FIG. 1 is a perspective view showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a fixed member on which a comb-shaped fixed electrode 11 is formed, and 2 denotes a movable member on which first and second movable electrodes 21A and 21B (see FIG. 2) are formed via an insulating layer. The members 3A and 3B are guide members. That is, a pair of comb-shaped movable electrodes 2 insulated from each other is arranged so as to mesh with the comb-shaped fixed electrode 1.
Here, a spring is assumed as the guide member, but any member having a function equivalent to this may be used. FIG. 2 is an explanatory diagram for explaining the principle according to the present invention. This shows a part of the section A in FIG.
One fixed electrode 11A, 11B and a pair of movable electrodes 21A,
21B are arranged as shown in FIG.
A and the fixed electrodes 11A and 11B are connected to the negative electrode of the power supply V, and the movable electrode 21B is connected to the positive electrode of the power supply V, so that the electric field strengths acting on the movable electrodes 21A and 21B are different from each other, and the electrostatic driving force F Is what you get. The electrostatic driving force F at this time is as follows: F = ε · n · L · V ² / 2d Here, L indicates the length of the comb electrode. At this time, a force is generated in the movable electrode as long as the movable electrode is in the fixed electrode. Therefore, the displacement can be increased by increasing the thickness of the fixed electrode. Further, since the generated force is proportional to the length L of the comb electrode, the electrostatic driving force F can be larger than that of the conventional one. FIG.
In the apparatus shown in FIG. 3, a force always acts on half of the total number of comb teeth during driving. However, in this embodiment, a force is always generated on all the number of comb teeth, so that a larger force can be obtained.

Therefore, in the configuration shown in FIG. 1, the guide member 3B and the fixed member 1 are connected as shown in FIG.
When a voltage V indicated by a solid line is applied between A and the fixed member 1, the movable member 2 moves in the direction (upward) indicated by the solid arrow according to the above principle. Further, the guide member 3A and the fixed member 1 are connected as follows, and a voltage V indicated by a dotted line is applied between the guide member 3B and the fixed member 1.
Is applied, the movable member 2 moves in the direction (downward) indicated by the dotted arrow according to the same principle. At this time,
Since a voltage is applied to the movable electrodes 21A and 21B via the guide members 3A and 3B, the guide member 3A and the movable electrode 21A, and the guide member 3B and the movable electrode 21B are connected to each other. FIG. 3 shows an outline of the manufacturing method. First,
In (a), an insulating film and Si are stacked on a silicon (Si) substrate. Next, after forming the outer shape of the movable portion by etching in (b), the movable portion is formed by etching from the back surface in (c).

In FIG. 1, one movable member is used, but two or more movable members can be laminated. FIG. 4 is a perspective view showing an embodiment in such a case, in which three sheets are stacked. By laminating three movable members at an appropriate interval in this manner, the above-described electrostatic force acts on each movable member, so that a driving force three times as large as that of FIG. 1 is obtained. When N sheets are stacked, N times the driving force can be obtained. FIG. 5 shows an outline of the manufacturing method. (I),
(B) is the same as FIG. In (c), an insulating layer and a sacrificial layer are formed, and a second substrate (Si, insulating film, Si) is laminated thereon as in (d), and then the outer shape of the second movable portion is formed in (e). . Further, in (f), the sacrificial layer, the insulating layer and the third substrate are laminated, and in (g), the outer shape of the third movable portion is formed. Finally, etching is performed from the back surface in (h) to form the first movable portion, and the sacrificial layer is removed to complete the process.

In FIG. 2, a pair of movable electrodes is provided via an insulating layer. However, one of the insulating layer and the movable electrode may be replaced with a dielectric. FIG. 6 is an explanatory diagram for explaining such a principle. This is because the movable electrode is 21
A only, and a dielectric (dielectric constant ε _A ) 21D is bonded to the fixed electrodes 11A and 11B so as to be opposed to the fixed electrodes 11A and 11B, and is disposed in a liquid such as Freon or alcohol having a higher relative dielectric constant ε _B than the dielectric 21D. Then, a voltage is applied as shown in the figure, whereby a driving force F similar to that of FIG. 2 can be obtained. Here, a ε _A <ε _B, when the electric field intensity of the upper surface E1, the lower surface of it and E2, the driving force F is expressed F = epsilon _B and (E1 ² -E2 ^2).

FIG. 7 shows a modification of FIG. This is a fixed member 1 having a comb-shaped fixed electrode 11C, and a movable electrode 2 which meshes with the fixed member 1 and slides with a slight gap between each comb tooth.
The movable member 22 composed of 2A and 22B is arranged. The movable electrodes 22A and 22B are insulated through an insulator 22C as in FIG. 1, and the fixed member 1 is provided with slight protrusions 4A and 4B so that the movable member 22 can slide with low friction. The movable member 22 is configured to contact only at the portion. That is, the portion including the protrusions 4A and 4B is
A, 1st, 2nd contact points 5 for applying a voltage to 22B
A and 5B are formed, the first contact 5A and the first movable electrode 22A and the second contact 5B and the second movable electrode 22B are respectively connected, and the two contacts are both fixed electrodes 11C via another insulator 22D. And insulated. Reference numerals 6A and 6B denote switches. When in the position shown in the figure, a positive voltage is applied to the second contact 5B and the second movable electrode 22B, and a negative voltage is applied to the fixed electrode 11C and the first contact 5A and the first movable electrode 22A. These relationships are reversed when voltages are applied and when the voltage is at the position indicated by the dotted line. From the above, it can be said that this embodiment corresponds to the one shown in FIG. 1 rotated by 90 degrees.

In such a configuration, when a voltage as shown by a solid line is applied to each electrode, an electric field generated between the first and second movable electrodes 22A and 22B and the fixed electrode 11C as shown in FIG. Displaced in the direction of the solid arrow. On the other hand, if a voltage as shown by a dotted line is applied to each electrode, the voltages of the first and second movable electrodes 22A and 22B become opposite to the above, and are displaced in the direction of the dashed arrow. By doing so, it is possible to realize an actuator capable of extracting a large displacement amount according to the length of the fixed electrode. Here, it is possible to improve the driving force by increasing the number of comb teeth or by arranging the movable members in parallel while maintaining an appropriate distance. Although not specifically shown, in this case, either one of the two movable electrodes and the insulator can be replaced with a dielectric.

FIG. 8 shows an example of a piston type actuator. This is because the first and second movable electrodes 23A and 23
B is laminated with the insulator 23C interposed therebetween to form the movable member 23, and is disposed in the cylindrical fixed electrode 11D having an inner diameter slightly larger than the outer diameter of the movable member. 1st, 2nd
Conductive guide members 3C and 3D are attached perpendicularly to the respective surfaces of the movable electrodes 23A and 23B, and are supported by bearings 7A and 7B. Then, for example, as shown in FIG.
When the voltage is applied between the second movable electrode 23B and the fixed electrode 11D, the movable member 23 is displaced in the direction of the arrow, and generates a force outside via the guide members 3C and 3D. . Since a displacement is possible according to the length of the cylindrical fixed electrode 11D, a large stroke can be obtained. FIG. 9 shows an example in which one of the two movable electrodes and the insulator are replaced by a dielectric, but the principle is as described in FIG. 23D is a dielectric.

FIG. 10 shows an example of an electrostatic motor, and FIG.
FIG. This is because a comb-shaped fixed electrode is used as a stator 11E, and four movable electrodes 24A, 24B, 24C, 24 insulated from each other so as to mesh with the stator 11E.
A rotor 24 having D is arranged, and two rotating electrodes 8A and 8B are provided on the shaft portion thereof to facilitate the rotational movement.
Further, the first rotating electrode 8A is provided with first and third movable electrodes (24A, 24C), and the second rotating electrode 8B is provided with a second movable electrode (24A, 24C).
And the fourth movable electrodes (24B, 24D) are connected to each other, and these are pressed and fixed by two brushes 9A (one is omitted) and 9B so as to be rotatable around the rotating electrodes 8A, 8B of the stator 11E. Then, the second brush 9B is short-circuited to the stator 11E, and the first brush 9A and the stator 1E are short-circuited.
1E, the movable electrodes 24A, 2A
4B, 24C, and 24D have voltage arrangements as shown in FIG. 11, an attractive force acts between the first and third electrodes and the stator, and rotation in the direction of the arrow occurs.

In the example of FIG. 10 as well, when the second and fourth movable electrodes are replaced with a dielectric such as a resin film and are driven not in the air but in a liquid such as chlorofluorocarbon or alcohol, a large torque is generated. It is possible to obtain. At this time, there is no need to short-circuit the second brush 9B with the stator 11E. The electrostatic attraction acting between the front and back surfaces of the first and third movable electrodes and the stator is reduced on only one side due to the dielectric, so that imbalance occurs in the force, resulting in rotational motion. As described above, since the electrostatic force acting on all the comb-shaped movable electrodes is always used during rotation, there is an advantage that a large torque can be obtained.

FIG. 12 shows another example of the electrostatic motor. This is because the disk-shaped rotor 25 is cut out at several places,
The movable electrodes 25A and 25B are formed so that a voltage can be applied to each electrode from above and below the shaft 10. At this time, the first and second movable electrodes 25A and 25B are insulated from each other via an insulator. Then, the conductive stators 11F and 11G sandwich the rotor 25 so as to maintain an appropriate gap with respect to the rotor 25.
Is fixed so that a voltage can be supplied to the second movable electrode 25B from above, and when a voltage is applied in the relationship shown in the drawing, the electrode rotates in the direction of the arrow.

[0018]

According to the present invention, a pair of comb-teeth movable electrodes insulated from each other with respect to the comb-teeth fixed electrode (may be constituted by an electrode and a dielectric instead of a pair of movable electrodes) ) Are arranged so as to mesh with each other, and by applying a voltage between one of the movable electrodes and the fixed electrode and the remaining movable electrode, a large driving force can be generated, and as a result, the displacement is also increased. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the principle of the present invention.

FIG. 3 is a schematic diagram for explaining the manufacturing method of FIG. 1;

FIG. 4 is a perspective view showing an embodiment in which movable members are stacked.

FIG. 5 is a schematic diagram for explaining the manufacturing method of FIG.

FIG. 6 is an explanatory diagram for explaining another principle of the present invention.

FIG. 7 is a perspective view showing a modification of FIG.

FIG. 8 is a schematic view showing an embodiment of a piston type actuator.

FIG. 9 is a schematic view showing another embodiment of the piston type actuator.

FIG. 10 is a perspective view showing an example of an electrostatic motor.

11 is a sectional view taken along the line AA'B of FIG.

FIG. 12 is a perspective view showing another example of the electrostatic motor.

FIG. 13 is a schematic diagram showing a conventional example.

FIG. 14 is a schematic diagram showing another example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed member 2 Movable member 10 Axis 11 Fixed electrode 12 Axis support part 21 Movable electrode 22 Movable member 23 Movable member 24 Rotor 25 Rotor 3A Guide member 3B Guide member 4A Projection 4B Projection 5A First contact 5B Second contact 6A Switch 6B switch 7A bearing 7B bearing 8A first rotating electrode 8B second rotating electrode 9A brush 9B brush 11A fixed electrode 11B fixed electrode 11C fixed electrode 11D fixed electrode 11E stator 11F stator 11G stator 21A movable electrode 22A first movable electrode 22B second movable electrode Electrode 22C Insulator 23A First movable electrode 23B Second movable electrode 23C Insulator 23D Dielectric 24A First movable electrode 24B Second movable electrode 24C Third movable electrode 24D Fourth movable electrode 25A First movable electrode 25B Second movable electrode

Continuation of the front page (56) References JP-A-4-368479 (JP, A) JP-A-4-248376 (JP, A) JP-A-3-230779 (JP, A) JP-A-4-222471 (JP) , A) JP-A-63-186570 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02N 1/00

Claims (11)

(57) [Claims] 1. A plurality of comb-shaped fixed electrodes are arranged in a row.
Each fixing member, the surface of the insulator, on the back of formation was
And the first and second comb-like teeth meshing with the comb teeth of the fixed electrode.
A movable member having a movable electrode in accordance with the number of the fixed electrodes; and a guide member for guiding the movable member mainly in one direction. One of the movable electrodes is provided with a first member via the guide member . Polar voltage is applied to the remaining movable electrode and
The constant electrode by applying a second polarity voltage, respectively, an electrostatic actuator, characterized in that for driving the movable member in one direction. 2. One of the first and second movable electrodes
And the insulator are replaced with a dielectric, and the remaining movable electrode is
Applies a voltage of the first polarity and the dielectric and the fixed electrode
The electrostatic actuator according to claim 1, wherein voltages of two polarities are applied . 3. The driving force is increased by laminating at least two or more movable members on the fixed member in the moving direction.
Electrostatic actuator according to claim 1 or 2, characterized in that to achieve reduction. 4. The electrostatic actuator according to claim 1, wherein the guide member is an elastic support spring. 5. The electrostatic actuator according to any one of claims 1 to 3 wherein the guide member is characterized by comprising a comb of the fixed electrode and the guide rail. 6. A cylindrical fixed electrode, of the fixed electrode
Section is provided so that it can move, the cross section is almost circular,
First and second movable electrodes formed on the front surface and the back surface, respectively , and the first and second movable electrodes are located inside the cylindrical fixed electrode.
A guide member that guides the movable electrode along the axial direction, and one of the movable electrodes has a first polarity through the guide member.
Is applied to the remaining movable and fixed electrodes in the second polarity.
Drive the movable member in one direction
An electrostatic actuator. 7. One of the first and second movable electrodes
And the insulator are replaced with a dielectric, and the remaining movable electrode is
Applies a voltage of the first polarity and the dielectric and the fixed electrode
7. The electrostatic actuator according to claim 6, wherein voltages of two polarities are applied . 8. A plurality of comb-shaped fixed electrodes are arranged in rows to form
Column, a stator disposed facing at predetermined intervals, the solid
To mate with the comb teeth of the fixed electrode, the first to fourth movable electrode, each insulated from one another via an insulator, the solid
A rotor having a number corresponding to the number of constant electrodes; a first rotating electrode and the second and fourth movable electrodes formed at both ends of a shaft of the rotor and connected to the first and third movable electrodes, respectively ; a second rotating electrode connected to said first, second round
First and second brushes for pressing and fixing the rotor to the stator via the transfer electrodes; applying a voltage of a first polarity between the first brush and the stator ;
By applying a voltage of the second polarity to the stator
Ri, electrostatic actuator, characterized in that cause rotation of said rotor. Wherein said insulator and the first, third movable electrode or the insulator and the second, placing the fourth movable electrode to the dielectric
Instead, a voltage of the first polarity is applied to the remaining movable electrodes,
A voltage of the second polarity is applied to the body and the fixed electrode, respectively.
Electrostatic actuator according to claim 8, characterized in that that. 10. A pair of rotors having first and second movable electrodes formed by cutting a disk and insulated from each other via an insulator, and a pair of rotatably sandwiching and supporting the rotor. A voltage having a first polarity is supplied from a shaft support portion of the stator to a second movable electrode;
An electrostatic actuator characterized in that the rotor is rotated by supplying a voltage of a second polarity to the movable electrode and the pair of stators . 11. A method in which one of the insulator and the movable electrode is replaced with a dielectric, and the remaining movable electrode has a first polarity electrode.
And a voltage of the second polarity is applied to the dielectric and the fixed electrode.
The electrostatic actuator according to claim 10, wherein each of the voltages is applied .