JPH0322886A - Electrostatic actuator - Google Patents

Abstract

PURPOSE:To reduce frictional force acting on a movable section and to improve effective thrust by providing an auxiliary power source which applies AC voltage or pulsating DC voltage across electrodes arranged to form a capacitor. CONSTITUTION:With each electrode 13a to 13e and 14a to 14e each capacitor is formed. Each fixed contact A is connected to corresponding electrodes 13a to 13e respectively, while each common contact C is connected to a line 17 in common. Between each fixed contact B of changeover switches 19a to 19e and electrodes 14a to 14e AC power sources 20a to 20e, which are auxiliary power sources, are respectively connected. In the condition where AC voltage or pulsating DC voltage is applied across electrodes 13a to 13e and 14a to 14e from the auxiliary power sources 20a to 20e, periodically fluctuating attractive forces are generated between electrodes 13a to 13e and 14a to 14e, so that the electrodes 13a to 13e and 14a to 14e will be oscillated.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an electrostatic actuator that uses electrostatic force to drive a load, particularly an industrial robot. Precision machinery, automobile equipment parts, home appliances. This relates to electrostatic actuators used to drive mechanical parts of office automation equipment, medical equipment, etc.

(Conventional technology) Traditionally, servo motors,
Magnetic actuators such as linear motors and stepping motors are used, and electrostatic actuators for driving the above-mentioned mechanical parts have only just begun to be put into practical use.

(Problem to be solved by the invention) In recent years, there has been an increase in the demand for technologies that require higher output density of actuators for driving the above-mentioned mechanical parts, more complex drive patterns, and control of minute displacements. be. However, with conventional magnetic actuators,
It is difficult to satisfy all such technical demands.

On the other hand, an electrostatic actuator that has the advantage of having a larger output/weight ratio than a magnetic actuator is considered to have the potential to satisfy the above requirements, but it is not practical. Electrostatic actuators have not appeared.

For example, in order to efficiently obtain thrust in an electrostatic actuator with a general configuration in which a mover made of a dielectric material is arranged between a pair of electrodes, the gap between the electrodes and the dielectric material must be on the order of several μm or less. It is important to set it to . However, in order to increase the output/weight ratio, it is necessary to make the members supporting the electrodes and the mover as thin as possible, but at the current technological level, even if highly rigid materials are used, It is very difficult to manage the above-mentioned voids on the order of several μm or less.

Therefore, when trying to obtain an electrostatic actuator with a high output/weight ratio, it is unavoidable that the electrode and the movable element are substantially in a state of being in partial contact. Therefore, it is inevitable that a relatively large frictional force is generated between the electrode and the movable element, which causes a reduction in the thrust of the movable element. Of course, if the reduction in thrust is severe, no effective thrust will be generated.

Generally, in order to increase the thrust force, it is sufficient to increase the horizontal force (force in the direction parallel to the electrodes) acting on the mover, but as mentioned above, when the electrodes and the mover are in contact with each other, In this case, the normal force acting on the contact surface increases proportionally and the frictional force also increases, so we cannot expect an increase in the effective thrust.

On the other hand, if the normal force acting on the contact surface is reduced to reduce the frictional force, the thrust force will also decrease accordingly, making it impossible to achieve the original purpose. In other words, in order to reduce only the frictional force acting between the electrode and the movable element, there is no other way than to reduce the coefficient of friction between the electrode and the movable element. However, the coefficient of friction generally depends largely on the material of the member that makes up the contact surface (friction surface) and its surface roughness, so in electrostatic actuators, the frictional force acting on the moving part is In order to reduce the amount, there is naturally a limit increase, and this point has remained an unresolved issue.

The present invention has been made in view of the above circumstances, and its object is to reduce the frictional force acting on the movable part regardless of the material of the member constituting the friction surface of the movable part, and thereby to reduce the frictional force acting on the movable part. An object of the present invention is to provide an electrostatic actuator that has effects such as improving thrust.

[Configuration of the Invention (Means for Solving the Problems) The present invention provides a dielectric material that is arranged between electrodes arranged to form a capacitor, and a power supply voltage applied between the rfj electrodes. In an electrostatic actuator that generates thrust between a body and an electrode or between electrodes, an auxiliary power source is provided for applying an AC voltage or a pulsating DC voltage between the electrodes.

In this case, a plurality of pairs of electrodes are arranged in a row on a pair of elastic electrode supports to provide a pair of Oka stators, and a dielectric is movable between the pair of fixed electrodes and r. A configuration in which an auxiliary power source applies an AC voltage or a pulsating DC voltage between the pair of electrodes such that a surface wave traveling in a direction opposite to the moving direction of the movable element is generated on the stator. It's good as well.

Further, in the electrostatic actuator, an electrode forming a capacitor and a dielectric body disposed between the electrodes are used, and the dielectric body or the electrode is displaced by applying a power supply voltage between the electrodes. It is also possible to arrange a lubricating electrically insulating material in the space formed between the dielectrics.

(Operation) When a power supply voltage is applied between the electrodes, thrust is generated between the dielectric and the electrodes or between the electrodes. Therefore, when the dielectric is fixed, the electrode is displaced, when both electrodes are fixed, the dielectric is displaced, or when one electrode and dielectric are fixed, the other electrode is displaced. That will happen.

When an AC voltage or a pulsating DC voltage is applied between the electrodes from an auxiliary power source, a periodically varying attractive force is generated between the electrodes, which causes the electrodes to vibrate. In general, it is empirically known that when a relative vibration phenomenon between two objects is observed at the contact surface between the two objects, a phenomenon occurs in which the coefficient of friction between the two objects decreases. . Therefore, in response to the vibration of the electrode as described above, the friction coefficient of the surface (friction surface) that comes into contact with the electrode decreases.
Effective thrust will improve.

On the other hand, when a plurality of pairs of electrodes are arranged in a row on a pair of elastic electrode supports, when a power supply voltage is applied between the electrodes, one pair of stator A thrust is generated between the movable element made of a dielectric material and the electrodes disposed therebetween, and the movable element is displaced. A state in which an AC voltage or a pulsating DC voltage is applied from an auxiliary power source to between the pair of electrodes such that a surface wave traveling in a direction opposite to the moving direction of the movable element is generated on the stator. Then, the contact surface between the stator and the mover will vibrate,
Similarly to the above, the friction coefficient of the contact surface decreases. In addition, at this time, due to the frictional force remaining between the movable element and the stator and the surface waves on the stator, a moving force is applied to the movable element in the direction opposite to the surface waves, that is, in the direction in which the vertebral force acts. become.

Furthermore, if a lubricating electrical insulating material is placed in the space formed between the electrode and the dielectric material, the dielectric constant of the electrical insulating material is higher than that of air or vacuum. , it is possible to increase the capacitance of the capacitor formed by the electrodes, thereby increasing the thrust force acting on the movable element. At this time, the electrically insulating material has lubricating properties, and the gap between the electrode and the dielectric can be maintained constant by the electrically insulating material, so that the coefficient of friction between the electrode and the dielectric decreases. Effective thrust is improved.

(Embodiments) Hereinafter, a plurality of embodiments of the present invention will be explained with reference to the drawings. First, the basic principles of the first to third embodiments will be explained based on FIGS. 5 to 7. .

In FIG. 5, stators 2 and 3 of an electrostatic actuator 1 are arranged in parallel with each other at a predetermined distance.
A pair of electrode supports 2a and 3a and these electrode supports 2a
and 3a, a pair of electrodes 2 supported and fixed respectively on opposite sides of the electrodes 3a.
b and 3b. As a result of this sideways,
Each electrode 2b and 3b of the stators 2 and 3 forms a capacitor. Further, the movable element 4 of the electrostatic actuator 1 is made of a dielectric material, and is provided between the stators 2 and 3 so as to be movable in a direction parallel to the electrodes 2b and 3b (left-right direction in the figure). At this time, the mover 4 and the stator 2,
3 is set to be as small as possible, and accordingly, the movable element 4 is in a state in which it is partially in contact with the stator 2.3.

Then, with the movable element 4 at a position offset from the center position of the electrodes 2b, 3b, as shown in FIG. 5, a DC voltage is applied between the electrodes 2b, 3b. When a capacitor 4 is charged, a certain movable element 4 receives an attractive force (thrust) from the dielectric in the direction of reducing the electrostatic energy of the capacitor and moves to the position where the electrostatic energy is minimum (the movable element 4 It is stopped and held at a position where the centers of the child 4 and the electrodes 2b and 3b coincide.

By the way, when the moving speed (sliding speed) of the mover 4 is relatively small, each frictional force Ff between the mover 4 and the stators 2 and 3 is expressed as Fl' - μFv However, μ: Sliding friction coefficient of the contact surface Fv: Obtained from the normal force acting on the contact surface.

The effective thrust Fa of the electrostatic actuator 1 is
The attraction force Fh that acts on the mover 4 in response to the application of a DC voltage between
It is determined as the difference between the frictional force 2Fr generated at each contact surface with the In other words, Fa - Fh - 2Fr - Fh - 2μFv Therefore, if the 11I friction coefficient μ of the contact surface is reduced, the effective thrust Fa can be improved.

Here, as a general phenomenon, when two objects that are in contact with each other are moved relative to each other, it is empirically known that when the moving speed is high, the coefficient of friction between the two objects decreases significantly. It is assumed that this phenomenon is caused by the mutual vibration of the objects in contact. In fact, although no clear physical explanation has been given, it has been confirmed that the friction between objects vibrating at high frequencies is significantly reduced.

Therefore, in the example of FIG. 5, the mover 4 and stators 2 and 3
In order to cause the above-mentioned reduction in the coefficient of friction between the electrodes 2b and 3b, a relatively high frequency (for example, on the order of KHz) is applied to the output of the DC 1t [5] for applying the DC voltage between the electrodes 2b and 3b. ) is provided with an AC power source 6 as an auxiliary power source for superimposing the AC voltage. As a result of this configuration, electrode 2b. Since a voltage that pulsates at a relatively high frequency is applied between 3b and 3b, the vertical force Fv acting on each contact surface between the movable element 4 and the stators 2 and 3 changes over time, causing the stator 2.3 begins to vibrate, and as a result, the coefficient of friction between the movable element 4 and the stators 2 and 3 is significantly reduced.

In addition, although FIG. 5 shows an example in which the dielectric body is on the mover side,
As shown in FIG. 6, it is also possible to arrange a pair of movers 8.9 in parallel on both sides of a stator 7 made of a dielectric material. That is, in this FIG. 6, movers 8 and 9 are
A pair of electrode supports 8a and 9a, and these electrode supports 8
It is composed of a pair of electrodes 8b and 9b supported and fixed on the opposing surfaces of electrodes a and 9a, respectively, and a sliding contact 8 is connected to each electrode 8b and 9b from a DC power source 5 and an AC power source 6.
It is designed to be energized via C and 9C. Therefore, in this configuration, the mover 8.9 is displaced when the 'Iji source is applied between the electrodes 8b and 9b.

Further, as shown in FIG. 7, a configuration in which a thrust force acts between the electrodes can also be adopted. That is, in FIG. 7, the stator 10 is constructed by arranging an electrode 10b on an electrode support 10a, and arranging a thin insulator 10c, which is a dielectric, to cover the electrode 10b. The electrode 1
0b is directly energized from a DC power source 5 and an AC power source 6. The movable element 11 is placed on the stator 10 in contact with the stator 10, and has an electrode 1lb arranged on the lower surface of the electrode support 11a. Electricity is supplied from the auxiliary power source 6 through the sliding contact 11c. Therefore, in this configuration, when power is applied between the electrodes 10b and llb, a thrust force acts between the electrodes 10b and llb, and the mover 11 is thereby displaced.

Now, FIG. 1 and FIG. 2 show a first embodiment of the present invention, which will be described below.

Incidentally, this first embodiment is an extension of the basic principle structure shown in FIG. 5 above.

In FIGS. 1 and 2, the stators 13 and 14 of the electrostatic actuator 12 include a pair of electrode supports 13X and 14x arranged in parallel with each other at a predetermined distance;
For example, five pairs of electrodes 13a to 13e and 1 are supported and fixed in a row on each opposing surface of these electrode supports 13x and 14x.
4a to 14e. As a result of this structure, each of the electrodes 13a to 13e and 14a to 14e forms a capacitor. Further, the movable element 15 of the electrostatic actuator 12 is made of a dielectric material, and is provided between the stators 13 and 14 so as to be movable in a direction parallel to each electrode row (horizontal direction in the figure). At this time, the gaps between the movable element 15 and the stators 13 and 14 are set to be as small as possible, as in the case of FIG. 5.

First changeover switches 16a to 16e are connected to the electrodes 13a to 13e, respectively, so as to correspond to each other. These changeover switches 16a to 16e are of a two-circuit type, and each fixed contact A is connected to a corresponding electrode 13a to 13e, respectively, and each common contact C is commonly connected to a line 17. In addition, the first changeover switch 16a
DC currents iX 18a to 18e are connected between each of the fixed contacts B to 16e and the electrodes 13a to 13e, respectively.

Second changeover switches 19a to 19e are connected to the electrodes 14a to 14e, respectively, so as to correspond to the electrodes 14a to 14e. These changeover switches 19a to 19e are also of a two-circuit type, and each fixed contact A is connected to a corresponding electrode 13a to 13e, respectively, and each common contact C is connected to the line 17.
are commonly connected. In addition, the changeover switch 19a~
AC power sources 20a to 20e, which are auxiliary power sources, are connected between each fixed contact B of 19e and each of the electrodes 14a to 14e, respectively. Note that the output frequency of the AC power supplies 20a to 20e is set, for example, on the order of KHz. Further, the first and second changeover switches 16a to 16e, 19a
19e are illustrated using contact symbols, but they can also be configured by a combination of static switching elements.

In the above structure, by selecting the switching states of the first changeover switches 16a to 16e according to the position of the movable element 15, an attractive force is applied to the movable element 15 between each of the electrodes 13a to 13e and 14a to 14e. (Thrust) It is possible to control the DC power sources 18a to 18e to apply a DC voltage that causes Fh to work. In other words, when the mover 15 is in the position shown in FIG.
By switching only the switch 6b to the ON state between the contacts (C-B) and switching the other first changeover switches 16a, 16C to 16e to the ON state between the contacts (C-A), the movable member 15 is turned on as shown by the arrow in the figure. A thrust Fh in the direction can be given.

When moving the mover 15 in this way, the first
Assuming that all of the second changeover switches 198 to 19e are in the ON state between their contacts (CB) as shown in the figure, a corresponding AC voltage IFj. Since a relatively high frequency AC voltage is applied from 20a to 20e, the electrodes 13a to 13
A periodically fluctuating suction force is generated between e and each of 14a to 14e. In other words, the mover 15 and the stators 13 and 14
The vertical force acting on each contact surface with the movable element 15 and the stator 13 changes over time, and the stators 13 and 14 vibrate at a relatively high frequency accordingly.
and 14 are significantly reduced, and the effective thrust of the electrostatic actuator 12 is improved.

In order to obtain the effect of reducing the coefficient of friction as described above, it is sufficient to vibrate only the portion corresponding to the movable element 15, rather than the entirety of the stator 13 and [4]. Therefore, as shown in FIG. 2, the movable element 15 corresponds to the corresponding electrode 13b.
13c and 14b, 14C and electrodes 13d located near the mover 15. The switching states of the second changeover switches 19a to 19e may be selected so that the AC voltage is applied only to the switch 14d, and when such control is performed, power consumption can be reduced. can be achieved.

A second embodiment of the invention is shown in FIG. 3 and will be described below. Incidentally, this second embodiment is also an extension of the basic principle structure shown in FIG. 5 above.

That is, in FIG. 3, the stators 22 and 23 of the electrostatic actuator 21 include a pair of electrode supports 22a and 23a arranged in parallel with each other at a predetermined distance, and each of these electrode supports 22a and 23a. For example, three pairs of electrodes 22b to 22d and 23b supported and fixed in a row on opposing surfaces.
~23d. As a result of this configuration, each of the electrodes 22b to 22d and 23b to 23d forms a capacitor.

On the upper surface side of the electrode support 22a of the stator 22, strip-shaped auxiliary electrodes 24a and 24b are provided at both end edges along the rows of the electrodes 22b to 22d. Also, stator 2
On the lower surface side of the electrode support 23a of No. 3, the electrode 2
The auxiliary electrode 24a is provided at both end edges along rows 3b to 23d.
, 24b, a strip-shaped auxiliary electrode 25a,
25b is provided. As a result, the auxiliary t'J5 m
2 4 a , 24 b and 25 a , 25 b each form a capacitor. On the other hand, the movable element 26 of the electrostatic actuator 21 is made of a dielectric material, and is provided between the stators 22 and 23 so as to be movable in a direction parallel to each electrode row. At this time, iJ Moko 26
The gaps between the stator 22 and the stator 22, 23 are set to be as small as possible, as in the case of FIG.

The auxiliary electrodes 24a, 24b and the auxiliary electrode 25a
, 25b, the output of an AC power supply 27 serving as an auxiliary power supply whose output frequency is set, for example, on the order of KHz is applied via a switch 28. Although not shown, each electrode 22b to 22d of the stator 22 23
and 23b to 23d, the DC power output is selectively applied as in the first embodiment.

According to such a configuration, when the switch 28 is turned on, the auxiliary electrodes 24a and 24b and between the auxiliary electrodes 25a. 25b
During this period, an AC voltage with a relatively high frequency is applied from the AC power source 27, and an attractive force that periodically fluctuates between each period is generated. Therefore, in this case as well, the stators 22 and 23 vibrate at a relatively high frequency, causing the movable element 26 and the stators 22 and 23 to vibrate at a relatively high frequency.
Since the coefficient of friction between the
The effective thrust of the electrostatic actuator 21 can be improved.

FIG. 4 shows a third embodiment of the invention, which will be described below. It should be noted that this third embodiment is also an extension of the storybook structure shown in FIG. 5 above.

That is, in FIG. 4, the fixed rods 30 and 31 of the electrostatic actuator 29 have a horizontal structure that is easily elastically deformed.

In other words, the stators 30 and 31 are a pair of elastic electrode supports 3 arranged in parallel with a predetermined distance from each other.
0a and 31a, and these electrode supports 30a and 31a
For example, two pairs of elastically deformable thin film electrodes 30b, 30c and 31b 31 are supported and fixed in a row on opposite sides of the electrodes 30b, 30c and 31b.
It is composed of c. As a result of this configuration, each of the electrodes 30b. A capacitor is formed by 30c, 31b, and 31c, respectively. Further, the movable element 32 of the electrostatic actuator 29 is made of a dielectric material, and this
．． 31 so as to be movable in a direction parallel to each electrode row. At this time, the gaps between the movable element 32 and the stators 30, 31 are set to be as small as possible, as in the case of FIG. 5.

The electrode 30b is a common contact C of a two-circuit type changeover switch 33.
The fixed contact A of this changeover switch 33
and the electrode 3lb, the output frequency is, for example, several KHz.
An AC power source 34, which is an auxiliary power source for orders, is connected. In addition, the fixed contact B of the changeover switch 33 and the AC Trir
i. A DC power supply 35 is connected between the power supply 34 and the power supply 34 . Then, the changeover switch 3 is also connected to the electrodes 30c and 31c.
6. An AC power source 37 and a DC power source 38, which are auxiliary power sources, are similarly connected.

At this time, the AC power supplies 34 and 37 are set so that the phases of their output voltage waveforms are different from each other. Specifically, the output voltage of these AC power supplies 34 and 37 is
, 3lb and between the electrodes 30c and 31c, a surface wave (indicated by arrow S) is generated in the stator 30, 31 that travels in the opposite direction to the moving direction of the mover 32 (arrow j direction). It is set so that

According to the above configuration, the output voltages of the AC power supplies 34 and 37 are applied between the electrodes 3ob and 31b and between the electrodes 30c and 31c, no matter which switching state the changeover switches 33 and 36 are in. Stator 30
．． 31 is vibrating in a state where a surface wave indicated by an arrow S is generated. At this time, with the movable element 32 in the position shown in FIG. , 31c, and the movable element 32 begins to move in the direction of arrow j. However, since the stators 30 and 31 are in a vibrating state, the The coefficient of friction is significantly reduced, and the effective thrust of the electrostatic actuator 29 is improved. In this case, the movable element 32 includes the stator 30.
31 and the surface waves on the stator 30.31, the thrust force is applied in the opposite direction to the surface waves, that is, in the moving direction j, thereby further improving the effective thrust force. be able to.

Moreover, since the stators 30 and 31 are elastically deformable and the electrostatic actuator 29 can be made flexible, the electrostatic actuator 29 can be mounted on a curved part,
This makes it possible to move the mover 32 in a curved manner.

In the third embodiment, both stators 30 and 31 are configured to be elastically deformable, but only one stator may be configured to be elastically deformable. Furthermore, although the first to third embodiments are all directed to the structure shown in FIG. 5, the basic principle structure shown in FIGS. 6 and 7 also applies. It is something that can be targeted.

Further, in the first to third embodiments, an AC power source is used as an auxiliary power source, but a power source that generates a pulsating DC voltage may be used instead.

Now, the fourth to sixth embodiments of the present invention will be described below. Prior to this, the basic principle of each embodiment will be explained based on FIG. 13.

In the electrostatic actuator 41 shown in FIG. 13, a mover 44 made of a dielectric material is disposed between a pair of electrodes 42 and 43 forming a capacitor, and a liquid electric insulating material 45 (currently has a dielectric constant higher than that of vacuum).

In such an electrostatic actuator 41, electrodes 42.
When a DC voltage is applied between the electrodes 42.
Attraction force FV acting perpendicularly between 43 and electrode 42.43
An attractive force (thrust force) Fh is generated between the movable member 44 and the
This suction force Fh is obtained by the following equation.

Fh-C(X)V2/2X -εo εg (εr -εg) WdV2/2
(2g+d) (2gεr +εg d)...0) However, C (X) is the capacitance between the electrodes 42.43, and X is the displacement amount of the portion of the movable element 44 located between the electrodes 42.43. (Length in moving direction>, V is the voltage supplied between the electrodes 42, 43, g is the gap size between the electrodes 42.4.3 and the mover 44, W is the frontage size of the electrodes 42, 43, εo lj is the dielectric constant of the vacuum, d is the thickness dimension of the movable element 44, εr is the relative dielectric constant of the movable element 44, and ξg is the relative dielectric constant of the electrically insulating material 45.

From the above equation, in a region where εg is relatively small compared to εr, (ε'-εg) can be regarded as approximately "1", so the relative dielectric constant εg of the electrical insulating material 45 is increased. It can be seen that the suction force Fh increases and reaches its maximum when εg reaches a certain large value.

On the other hand, the effective thrust of the electrostatic actuator 41 is obtained by subtracting the friction force between the movable element 44 and the electrodes 42 and 43 from the attraction force Fh. At this time, if the moving speed (sliding speed) of the mover 44 is relatively small, the frictional force between the mover 44 and the electrodes 42 and 43 can be reduced by lowering the friction coefficient μ of their contact surfaces. . In order to reduce such a coefficient of friction μ, it is effective to use a lubricant, so as the electrical insulating material 45,
If a material with high lubricity is used and the dielectric constant εg of the electrical insulating material is appropriately selected, the effective thrust can be increased.

FIG. 8 shows a fourth embodiment of the present invention that utilizes the above principle, and will be described below.

That is, in FIG. 8, the stators 47 and 48 of the electrostatic actuator 46 include a pair of electrode supports 47a and 48g arranged in parallel with each other at a predetermined distance, and each of these electrode supports 47a and 48a. It is composed of, for example, a pair of electrodes 47b and 48b supported and fixed on opposing surfaces. As a result of this configuration, each of the electrodes 47b and 48b
A capacitor is formed by And stator 47
, 48 are disposed between the stators 47, 48 and the movable elements 49. Four movers made of dielectric material are disposed between the stators 47, 48 and the mover 49, and a lubricating liquid electric insulating material 50 is provided in the space formed between the stators 47, 48 and the mover 49. Filled.

In this configuration, the electrodes 47b, 48 from the state shown in FIG.
When a voltage is applied from the DC power supply 51 between the movable elements b, an attractive force acts on the four movers in the direction of the arrow, causing them to be displaced.

Here, in FIG. 9, the frontage dimension W of the electrodes 47b and 48b is shown.
is 20+m, the thickness d of the mover 49 is 11, the mover 4
Under the condition that the dielectric constant ε' of the electric insulating material 50 is rl200J, the dielectric constant εg of the electrical insulating material 50 is changed from "1" to rl200J.
The state of change in the capacitance mc(X) between the kino electrodes 47b and 48b when the capacitance was changed to 0 J is shown as the ratio of change (C(X)/X) to the displacement amount X of the movable element 49. However, in FIG. 9, the gap size g (-1 μm, 5 μm, 110 μm) between the electrodes 47b, 48b and the mover 49 is used as a parameter. From this FIG. 9, the electrical insulating material 50
It can be seen that when the relative permittivity εg of the material is in the range of about 1 to IOOOJ, C(X)/X increases rapidly as the relative permittivity εg increases.

Therefore, as shown in equation (1) above, the DC power supply 51
If the output voltage ■ is constant, the attractive force Fh acting on the movable element 49 will be directly proportional to C(X)/X shown in FIG. Therefore, FIG. 10 shows the relationship between the dielectric constant εg of the electrically insulating material 50 and the rate of increase in the attractive force Fh using the gap size g (-1 μm 5 μm 1 10 μm) as a parameter. However, the rate of increase of the attractive force Fh is set to "1" when the dielectric constant is εg or rlJ (that is, when the electric insulating material 50 is not filled).

FIG. 10 shows that the attractive force Fh acting on the four movers (that is, the thrust of the electrostatic actuator 41) is
This shows that the condition varies greatly depending on whether or not it is filled.

In other words, the above-mentioned attractive force Fh can be determined by selecting the relative dielectric constant εg of the electrical insulating material 50 to an appropriate value.
However, in the case of 1 μm, it is about 20 times, and in the case of 5 μm, it is about 1
00 times, and in the case of 10 μm, the soil is added up to about 180 times.

In summary, according to this embodiment, the attraction force acting on the four movers increases, and the presence of the lubricating electrical insulating material 50 causes the four movers and the stator 47.
As a result, the effective thrust of the electrostatic actuator 46 can be improved.

FIG. 11 shows a fifth embodiment of the present invention that utilizes the same principle as the fourth embodiment, and will be described below.

That is, in FIG. 11, the stators 53 and 54 of the electrostatic actuator 52 include a pair of electrode supports 53a and 54a arranged in parallel with each other at a predetermined distance, and each of these electrode supports 53a and 54a. It is composed of, for example, a pair of electrodes 53b and 54b supported and fixed on opposing surfaces. As a result of this configuration, each of the electrodes 53b and 54
b forms a capacitor. And stator 5
A movable element 55 made of dielectric material is arranged between 3 and 54. Furthermore, on each opposing surface of the electrode supports 53a and 54a, a lubricating gel-like or solid electrically insulating material 56a and 56b such as N-methylformamide is applied.
is adhered or coated to cover the electrodes 53b and 54b, thereby making the stator 53.5
4 and the movable element 55, an electrically insulating material 56a. 56b is arranged.

This embodiment having such a configuration also achieves the same effects as the fourth embodiment, and in particular, according to this embodiment, the gap formed between the stator 53, 54 and the movable element 55 can be reduced. The dimensions can be effectively kept small, which can be expected to further improve the thrust.

FIG. 12 shows a sixth embodiment of the present invention which has the same effects as the fifth embodiment, and will be described below.

That is, in FIG. 12, the stators 58 and 59 of the electrostatic actuator 57 include a pair of electrode supports 58a and 59a arranged in parallel with each other at a predetermined distance, and each of these electrode supports 58a and 59a. For example, two pairs of electrodes 58b, 58c and 59b supported and fixed in a row on opposing surfaces.
, 59c. As a result of this configuration, a capacitor is formed by each of the electrodes 58b, 58c and 59b, 59c. A movable element 60 integrally having dielectric bodies 60a and 60b arranged at a predetermined interval is arranged between the stators 58 and 59. Further, on the opposite sides of the electrode supports 58a and 59a, gel-like or solid electrically insulating materials 61a and 61b having lubricity are adhered or coated so as to cover the electrodes 58b, 58C and 59b, 59c. At the same time, another space formed between the stators 53, 54 and the movable element 55 is filled with a liquid electrically insulating material 62.

[Effects of the Invention] In the electrostatic actuator recited in claim 1, by applying a power supply voltage between the electrodes, a thrust is generated between the dielectric material disposed between the electrodes and the electrodes or between the electrodes. In this device, the electrodes are vibrated by applying an alternating current voltage or a pulsating direct current voltage between the electrodes, so that the movable portion is made to vibrate regardless of the material of the member constituting the friction surface of the movable part. It is possible to reduce the frictional force acting on the parts, thereby making it possible to improve the effective thrust. Further, since the above-mentioned air gap can be made as close to zero as possible, it is possible to further improve the expired thrust and increase the output/volume ratio.

Furthermore, since there is no need to strictly control the air gap between the movable part and the stationary part, there is no problem even if the structural rigidity is significantly reduced, and the output/mass ratio can be increased.

In the electrostatic actuator according to claim 2, the stator provided with a plurality of pairs of main poles is configured to be elastically deformable, and a movable element made of a dielectric material is provided, and a movable element is provided on the stator with respect to the electrode. Since the configuration is such that an AC voltage or pulsating DC voltage is applied to generate a surface wave traveling in the opposite direction to the moving direction of the movable element, the vibration caused by the surface wave reduces the frictional force acting on the two moving parts. It is possible,
Effective thrust can be improved. At this time, forward moving force is superimposed on the movable element due to the frictional force remaining between the movable element and the stator and the above-mentioned surface waves, and this substantially eliminates the negative effect of the frictional force on the thrust force. can be ignored.

In the electrostatic actuator according to claim 3, a thrust force is generated between the electrode and a dielectric material disposed between the electrodes by applying a power supply voltage between the electrodes. Since the structure is such that a lubricating electrical insulating material is placed in the space formed between the dielectric materials, the attraction force between the electrodes and the thrust force can be improved, and the frictional force between the electrodes and the dielectric material can be reduced. As a result, the effective thrust will improve.

[Brief explanation of the drawing]

1 and 2 are side views schematically showing a first embodiment of the present invention together with an electrical configuration, and FIG. 3 is a perspective view schematically showing a second embodiment of the present invention together with an electrical configuration. 4 is a diagram equivalent to FIG. 1 showing the third embodiment of the present invention, and FIGS. 5 to 7 are diagrams equivalent to FIG. 1 showing the basic principle structure of the first to third embodiments. It is. 8 to 10 show a fourth embodiment of the present invention, and FIGS. 8(a) and (6) are a view corresponding to FIG. 1 and a schematic front view, and FIG. 9 and FIG. 10
The figure is a characteristic curve diagram for explaining the action. 11 is a diagram corresponding to FIG. 1 showing a fifth embodiment of the present invention, FIG. 12 is a diagram corresponding to FIG. 1 showing a sixth embodiment of the present invention, and FIG.
1A and 1B are a view corresponding to FIG. 1 and a front view, respectively, showing the basic principle structure of the fourth to sixth embodiments. In the figure, 1, 12.21, 29, 41, 46.52.57
is an electrostatic actuator, 2, 3, 7, ] 0, 13,
14, 22, 23, 30, 31,
4748, 5B, 5J. 58.59 is a stator, 2a,
3a, 8b, 9b, 10b, llb,
13a~]3e, 14a~1
4 e, 2 2 b ~ 2 2 d,
2 3 b~23d, 30b, 30c,
3lb, 31c, 42, 43, 4
7b, 48b, 53b, 54b, 58
b, 58c. 59b, 59c are electrodes, 4, 8, 9,
11, 15, 26, 32. 44,
49. 55 is a mover (dielectric), 5.18a to 18
e, 3538.51 is a DC power supply, 6. 2 0 a
~20e, 27.34.37 is AC power lf
i. (auxiliary power supply), 10c is an insulator (dielectric), 24
a, 24b, 25a, 25b are auxiliary electrodes, 30a. 31
．． a is an electrode support, 45, 50.56a, 56b, 61
a, 61. b, 62 is an electrically insulating material, 60 is a mover, 6
0a and 60b indicate dielectric materials. l Fig. 3 Fig. 29 Fig. 4 Fig. 1:・ Fig. 2 Fig. 5 Blade 6 Steering (8) Ditch 7 Nu No. 8 X (b) Fig. 9

Claims (1)

[Scope of Claims] 1. Comprising electrodes arranged to form a capacitor and a dielectric arranged between the electrodes, the dielectric and the electrodes can be connected by applying a power supply voltage between the electrodes. 1. An electrostatic actuator that generates thrust between electrodes or between electrodes, characterized in that an auxiliary power source is provided for applying an alternating current voltage or a pulsating direct current voltage between the electrodes. 2. It has a pair of stators in which a plurality of pairs of electrodes are arranged in rows on a pair of elastic electrode supports, and the dielectric is a mover disposed between the pair of stators. configured as,
The auxiliary power source is configured to apply an AC voltage or a pulsating DC voltage between the pair of electrodes such that a surface wave traveling in a direction opposite to the moving direction of the movable element is generated on the stator. The electrostatic actuator according to claim 1, characterized in that: 3. An electrostatic actuator comprising electrodes forming a capacitor and a dielectric disposed between the electrodes, the dielectric or the electrode being displaced by applying a power supply voltage between the electrodes, wherein the electrode and an electrostatic actuator, characterized in that a lubricating electrical insulating material is disposed in a space formed between dielectrics.