JP3480035B2 - 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 applied to drive machines such as industrial robots, precision machines, automobile equipment parts, home appliances, Affis automation equipment, medical welfare equipment and the like.

[0002]

2. Description of the Related Art Industrial robots, precision machines, automobile equipment parts, home appliances, Affis automation equipment,
BACKGROUND ART A rotary motor, a linear motor, a stepping motor, etc., which uses magnetic force are used to drive machines such as medical and welfare equipment.

Also, electrostatic actuators have been developed as those that generate driving force. This electrostatic actuator generates a driving force by utilizing an electrostatic force generated between electrodes composed of a stator and a mover.

However, this electrostatic actuator has the following problems. (a) The electrostatic force is more effective than a rotary motor or the like that uses electromagnetic force when displacing on a minute scale with a distance of μm to nm. This allows the electrostatic actuator to
It has to be an extremely small shape.

In order to obtain the torque or force of the electrostatic actuator, the gap between the electrodes should be as narrow as possible,
Further, it is necessary to make the gap between the stator and the mover as small as possible.

However, it is desired that a member and a mover that support each electrode be as thin as possible. In the present technology, a member having insufficient rigidity is used to manage a gap of several μm or less. Is difficult. (b) When the gap between the stator and the mover becomes several μm, the surface roughness and waviness of the stator and the mover affect the frictional force generated between the solid surfaces of the two. As a result, the thrust generated between the stator and the mover is significantly consumed, and the execution output is reduced.

For this reason, only an electrostatic actuator having such a small size that the gap between the stator and the mover can be reliably maintained could be manufactured. (c) In the electrostatic actuator of the type that deforms by using the attraction force between the electrodes, if the gap between the electrodes is increased to increase the stroke, the output of the actuator will be significantly reduced.

For this reason, a displacement of only a few micrometers can be obtained with one driving unit. (d) The above problems can be solved by filling some alcohol-based liquid between each electrode.However, this alcohol-based liquid has a high flammability and may cause a fire or explosion if a high voltage is applied. There is.

It is also conceivable to fill water between the electrodes, but the resistance is relatively small and there is a problem with the insulating property, and in addition, AC drive is necessary to avoid electrolysis,
Energy loss tends to increase.

[0010]

As described above, it is difficult to narrow the gap between the electrodes, and even if the gap is narrowed, the effective output is affected by the surface roughness of each electrode. Get smaller. In addition, even if the gap is lengthened to increase the stroke, the output is significantly reduced.

In order to solve such a problem, even if it is filled with an alcohol-based liquid, it is highly flammable and may cause a fire, and even if it is filled with water, it has a problem of insulation and an alternating current. Drive is required and energy loss is large. Therefore, it is an object of the present invention to provide an electrostatic actuator capable of significantly increasing the effective output.

[0012]

According to a first aspect of the present invention, in an electrostatic actuator for generating an electrostatic force between at least two electrodes, a liquid crystal having a high relative permittivity is filled between at least each electrode to achieve the above object. It is an electrostatic actuator that attempts to achieve

According to the first aspect, in the electrostatic actuator in which the mover is arranged between at least two electrodes and the thrust is exerted on the mover by the electrostatic force generated between these electrodes, at least between the electrodes is high. It is an electrostatic actuator which is filled with a liquid crystal having a relative dielectric constant to achieve the above object.

According to the second aspect, the liquid crystal has a relative permittivity corresponding to the gap between each electrode and the mover so that the thrust acting on the mover becomes a predetermined value. According to claim 1,
A protective film made of polymerized liquid crystal is formed on each of the opposing electrode surfaces.

According to the first aspect, the liquid crystal forming the protective film has a relative dielectric constant higher than that of the liquid crystal filling between the electrodes. According to claim 3, at least 2
An electrostatic actuator in which a gap between the electrodes is displaced by a suction force between two electrodes, and the liquid crystal having a high relative dielectric constant is filled between at least the electrodes to achieve the above object.

According to a fourth aspect of the present invention, in an electrostatic actuator having at least one electrode of two electrodes arranged facing each other as an electrode group, a liquid crystal having a high relative dielectric constant is provided at least between the electrodes. It is an electrostatic actuator that is filled to achieve the above object.

According to claim 5, the other electrode is a film-like electrode having elasticity. According to claim 6, a plurality of unit actuators for filling the liquid crystal having a high relative dielectric constant between the electrodes arranged to face each other to generate an attractive force between these electrodes are formed, and these unit actuators are stacked in the displacement direction. The electrostatic actuator is intended to achieve the above object.

According to claim 7, the fixed first electrode group, the elastic electrode support, and the second electrode arranged at a position corresponding to the first electrode group with respect to the electrode support. Electrode group, a liquid crystal having a high relative permittivity filled at least between the first and second electrode groups, a mover mounted on the electrode support, and the first and second electrode groups. And an energizing means for selectively energizing the electrostatic actuator to achieve the above object.

According to claim 8, a pair of coil-shaped electrodes adhered to each other via an insulating film, a liquid crystal having a high relative dielectric constant that fills a space between coil pitches of the coil-shaped electrodes, and the coil-shaped electrodes are energized. An electrostatic actuator that includes an energizing means for performing the above-mentioned purpose and is intended to achieve the above-mentioned object.

According to claim 9, an electrode group in which a plurality of electrodes are arranged, a film electrode having elasticity arranged on the electrode group via an insulating film, at least the electrode group and the film electrode An electrostatic actuator which is provided with a liquid crystal having a high relative permittivity filled between the electrode and an energizing means for selectively energizing between the film-like electrode and each electrode of the electrode group. Is.

According to a tenth aspect, a first electrode group in which a plurality of electrodes are arranged, a second electrode group including a plurality of electrodes arranged to face the first electrode group, and these first electrode group A movable element made of a polymer material, which is disposed between the first and second electrode groups and is deformed when an electric field is applied, and a relative permittivity of the relative permittivity filled between the first and second electrode groups. An electrostatic actuator that has a high liquid crystal and is intended to achieve the above object. According to claim 11, the liquid crystal is a liquid or gel liquid crystal. According to claim 12, the liquid crystal has a nematic phase or a cholesteric phase.

[0022]

According to the first aspect of the present invention, when an electrostatic force is generated with at least two electrodes filled with a liquid crystal having a high relative dielectric constant, for example, an attractive force generated between these electrodes,
And the thrust acting on the mover arranged between the electrodes increases.

According to the first aspect, when the electrostatic force is generated in the state where the liquid crystal having a high relative dielectric constant is filled between at least two electrodes, the thrust acting on the mover arranged between the electrodes increases. To do.

In this case, according to the second aspect, liquid crystal having a relative dielectric constant corresponding to the gap between each electrode and the mover is filled to obtain a predetermined thrust. According to claim 1,
By forming a protective film on each electrode surface, each electrode surface can be protected when the mover moves.

Moreover, according to the first aspect, if the protective film having a relative dielectric constant higher than that of the liquid crystal filled between the electrodes is used, the thrust of the mover can be further increased. According to the third aspect, when the electrostatic force is generated in the state where the liquid crystal having a high relative dielectric constant is filled between at least two electrodes, the attractive force between the electrodes increases.

According to the fourth aspect, if an electrostatic force is generated with at least the electrodes and the electrode group filled with the liquid crystal having a high relative dielectric constant, for example, between the electrodes and the electrode group. The thrust acting on the mover arranged is increased.

In this case, according to the fifth aspect, by forming the other electrode into a film electrode having elasticity, the film electrode moves in a wavy shape. According to the sixth aspect, when a plurality of unit actuators are formed and stacked, the unit actuators are displaced by the increased attraction force between the electrodes.

According to claim 7, the first oppositely arranged
When the second electrode group is selectively energized, the second electrode group is displaced by the suction force increased by the liquid crystal between the first electrode group and the second electrode group, and responds to this displacement. As a result, the electrode support moves in a wave shape, for example, and the mover moves in response to this movement.

According to the eighth aspect, when liquid crystal having a high relative permittivity is filled between the coil pitches of the pair of coil-shaped electrodes for energization, the attraction force increased by the liquid crystals causes a gap between the coil pitches of the coil-shaped electrodes. Displace.

According to the ninth aspect, when electricity is applied between the electrode group and the film-like electrode, the film-like electrode moves in a wavy shape by the suction force increased by the liquid crystal between the electrode group and the film-like electrode. According to the tenth aspect, when the first and second electrode groups are selectively energized, the mover made of the polymer material arranged between the electrode groups is deformed by the suction force increased by the liquid crystal. And move.

According to the eleventh aspect, the liquid or gel liquid crystal is filled. According to claim 12, the liquid crystal is
It exhibits a nematic phase or a cholesteric phase.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. (1) First, the basic operating principle of the electrostatic actuator will be described in describing the embodiments.

FIGS. 1, 2 and 3 are diagrams showing the basic operation principle of the electrostatic actuator. 1 is a front view, FIG. 2 is a side view, and FIG. 3 is a front view. Terminals 3 and 4 are connected to a pair of electrodes 1 and 2 arranged to face each other to form capacitors. Of these, a switch 5 is connected to the terminal 3, and the electrodes 1, 2 are connected via the switch 5.
A DC power supply V is connected between them.

A mover 6 is arranged between the electrodes 1 and 2, and a space between the electrodes 1 and 2 and the mover 6 is filled with a liquid crystal 7. With such a configuration, the attraction force Fv acts on each of the electrodes 1 and 2, and when the mover 6 is not completely between the electrodes as shown in FIG. The suction force Fh acts between the child 6.

Of these, the suction force Fh is represented by Fh = {ε0 εrc (εrs-εrc) Wd} V ² ÷ {2 (2g + d) (2gεrs + εrcd)} (1).

Here, ε0: dielectric constant of vacuum εrc: relative permittivity of liquid crystal εrs: relative permittivity of mover or gel W: frontage length between electrodes d: thickness of mover V: supplied to electrodes Voltage g: Gap between electrode and mover From this equation, in the region where the relative permittivity εrc of the liquid crystal 7 is relatively smaller than the relative permittivity εrs of the mover 6, the relative permittivity εrc of the liquid crystal 7 serving as a medium is It can be seen that the suction force Fh increases as it is increased, and shows a peak at a certain value.

Further, as shown in the side views of FIGS. 3 and 4,
When the liquid crystal 7 is a solid or a gel having a high dielectric constant, the attractive force Fv acting between the electrodes 1 and 2 is y (= 2g + d), which is the distance between the electrodes 1 and 2. It is obtained by partially differentiating the electrostatic energy accumulated in the capacitor formed by the electrodes 1 and 2 by the distance y.
That is, the suction force Fv ^{is, Fv = -ε0 εrcWL · V 2} /2 (2g + d) 2 -ε0 εrc (εrs-εrc) {4gεrs + (εrs-εrc) d} ÷ 2 (2g + d) 2 (2gεrs + dεrc) 2 × WdV ^It is represented by ² x (2).

Where L is the length of the electrode
x: Displacement between the pair of electrodes of the mover, or as shown in FIGS. 5 and 6, there is no solid or the like having a different dielectric constant, and the space between the electrodes 1 and 2 is charged with a single liquid crystal 7. If there are, the suction force Fv acting between these electrodes 1 and 2 to each other is represented by ^{Fv = -ε0 εrcWL · V 2 /} 2D 2 ... (3). D: distance between electrodes (= 2g + d)
Is.

By the way, when the mover 6 moves as shown in FIG. 1, the frictional force Ff when the change in the sliding speed of the mover 6 is not large is represented by Ff = μN (4)

Here, μ: sliding friction coefficient N: vertical drag force received from the contact surface From this equation (4), the frictional force Ff is reduced by reducing the value of the sliding friction coefficient μ by using a medium having high lubricity. It turns out that can be made smaller.

The effective thrust Fa of the electrostatic actuator is the attraction force Fh and the friction force Ff generated when the mover 6 moves.
It is calculated as the difference between That is, Fa = Fh-Ff (5). Therefore, the effective thrust Fa can be increased by filling the space between the electrodes 1 and 2 with liquid crystal having a high relative dielectric constant and a high lubricity. (2) Next, a first embodiment of the present invention will be described.

7 and 8 are configuration diagrams of the electrostatic actuator. FIG. 7 is a front view and FIG. 8 is a side view. Terminals 12 and 13 are connected to a pair of electrodes 10 and 11 arranged to face each other to form capacitors. Of these, a switch 14 is connected to the terminal 12, and a DC power supply V (for example, 100 V) is connected between the electrodes 10 and 11 via the switch 14.

The electrodes 10 and 11 are fixedly supported by the electrode supports 15 and 16, respectively. A mover 17 is arranged between the electrodes 10 and 11.

Here, the width W of each electrode 10, 11 is set to 1
0 mm, the thickness d of the mover 17 is 1 mm, and the relative permittivity εrs is 10,000. The space between the electrodes 10 and 11 and the mover 17 is filled with a liquid or gel liquid crystal 18 having a relative permittivity εrc higher than the vacuum permittivity ε0.

Here, the liquid crystal 18 will be described.
When this liquid crystal is defined, a subtle difference in the chemical structure of the liquid crystal affects the appearance of the liquid crystal phase. For example, the difference in alkyl chain length, the presence or absence of a substituent, and the like. The liquid crystal 18 used here is
It includes a compound exhibiting a liquid crystal phase, a compound having a chemical structure similar to that of the substance, and even a substance.

The liquid crystal phase is classified into a nematic phase, a cholesteric phase recognized as its optically active state, and a smectic phase. Any liquid crystal phase can be used in the electrostatic actuator of the present invention.

The liquid crystal state is a state of a substance existing between the liquid and the liquid crystal. Liquids have zero-dimensional order, and crystals have three-dimensional order. The liquid crystal has an intermediate one- or two-dimensional order, and the nematic phase (cholesteric phase) corresponds to one dimension and the smectic phase corresponds to two dimensions.

The same liquid crystal substance may exhibit a plurality of liquid crystal phases. In that case, the nematic phase (cholesteric phase) appears at a higher temperature than the smectic phase. this is,
It depends on the order of both phases. The viscosities of both phases reflect the degree of order, and the nematic phase (cholesteric phase) exhibits a lower viscosity than the smectic phase.

Therefore, since the lubricant of the electrostatic actuator of the present invention preferably has low viscosity, it is more preferable than the nematic phase (cholesteric phase). The liquid crystal 18 to be filled in the electrostatic actuator of the present invention is a single substance of a compound exhibiting a liquid crystal phase, a substance composed of a plurality of the compounds, and additionally has a chemical structure similar to that of a liquid crystal but does not exhibit a liquid crystal phase, that is, is defined as the above liquid crystal You may make it comprised by adding the single compound or multiple compounds.

On the other hand, the lubricant used in the electrostatic actuator of the present invention needs to have at least fluidity.
It is necessary that crystallization does not occur over the actual operating temperature range.

The melting point of an ordinary compound alone is higher than room temperature. In order to prevent crystallization in the operating temperature range of the electrostatic actuator of the present invention, the melting point is lowered by mixing a plurality of compounds. That is, a plurality of compounds can be preferably used.

The liquid crystal has anisotropy in dielectric constant. Liquid crystal molecules are elongated rod-shaped molecules. In general, the direction in which the molecular length is long is called the molecular long axis direction, and the direction orthogonal to this is called the molecular short axis direction.

From the viewpoint of the dielectric constant Δε, liquid crystals can be classified into two types, Δε> 0 and Δε <0. Both have different response behavior to the electric field. When an electric field exists, the direction in which both have a large dielectric constant is arranged along the direction of the electric field. The liquid crystal with Δε> 0 is aligned with the major axis of the molecule in the electric field direction, and the liquid crystal with Δε <0 is aligned with the minor axis of the molecule in the electric field direction.

In the electrostatic actuator of the present invention, Δε> 0
And Δε <0 can be preferably used. Most liquid crystals with Δε> 0 have a polar group, for example, a group having a large dielectric constant such as fluorine, chlorine or cyano group at one end of the long axis of the molecule. Examples of typical liquid crystal compounds are given below.

[0055]

[Chemical 1] The number of liquid crystals with Δε <0 is not so large, but it has a polar group in the minor axis direction of the molecule. Typical examples are given below.

[0056]

[Chemical 2]

Next, the operation of the electrostatic actuator constructed as described above will be described. When the switch 14 is closed and the DC power supply V is connected between the terminals 12 and 13, the attraction force Fh expressed by the above formula (1) acts between the electrodes 10 and 11 and the mover 17.

As a result, the mover 17 outside the electrodes 10 and 11 (forming a capacitor) has a DC power source V
Each of the electrodes 10, which receives the attraction force Fh proportional to the square of
11 is sucked into.

Here, the change in the suction force acting on the mover 17, that is, the thrust force will be described. FIG. 9 shows each electrode 10, 11.
The frontage width W is 10 mm, the thickness d of the mover 17 is 1 mm,
The relative permittivity εrs is 10,000, and these electrodes 10, 11 are
With the gap g between the armature and the mover 17 as a parameter
The thrust is shown when m, 5 μm and 10 μm are fixed and the relative permittivity εrc of the liquid crystal 18 is changed between 1 and 10000.

As shown in this figure, it can be seen that as the relative permittivity εrc of the liquid crystal 18 is increased, the thrust increases rapidly in the range of relative permittivity 1 to 10,000. Further, it is found that the smaller the gap g is, the larger the thrust is obtained, and the peak of the thrust shows the relative permittivity εrc which is different for each gap g.

FIG. 10 shows the rate of increase in thrust at this time, which is compared with the value obtained when the dielectric constant is 1. For example, the rate of increase in thrust is such that the gap g is 1 μm.
It is possible to obtain thrust of about 20 times when m is m, about 80 times when the gap g is 5 μm, and about 150 times when the gap g is 10 μm.

Further, when the gap g becomes large, the effect is particularly large, for example, the gap 10 μm.
Even with m, the same thrust as in the case of a gap of 1 μm can be generated.

Therefore, by filling the liquid crystal 18 having the optimum relative dielectric constant according to the gap g between the electrodes 10 and 11 and the mover 17, it is possible to obtain an electrostatic actuator that obtains a desired thrust.

As described above, in the first embodiment,
Since the liquid crystal 18 having a high relative permittivity εrc is filled between the two electrodes 10 and 11, the thrust acting on the mover 17 arranged between the electrodes 10 and 11 can be increased.

In this case, the electrodes 10, 11 and the mover 17
The maximum thrust can be obtained by filling the liquid crystal 18 having the relative permittivity εrc corresponding to the gap g between and. (3) Next, a second embodiment of the present invention will be described. The same parts as those in FIGS. 7 and 8 are designated by the same reference numerals, and detailed description thereof will be omitted.

11 and 12 are configuration diagrams of the electrostatic actuator. FIG. 11 is a front view and FIG. 12 is a side view. On the surfaces of the respective electrode surfaces of the electrodes 10 and 11 facing each other, insulating gel-like liquid crystals 19a and 1a having a high lubricity and a relative dielectric constant εrc higher than the vacuum dielectric constant ε0, respectively.
9b is adhered or coated.

Together with this, these gel-like liquid crystals 19a, 1
A space between 9b and the mover 17 is filled with a gel or liquid crystal 18 similar to that of the first embodiment. In addition,
The gel-like liquid crystals 19a and 19b are polymerized liquid crystals and have a higher relative dielectric constant than the liquid crystal 18.

Next, the operation of the electrostatic actuator constructed as described above will be described. DC power supply V for each terminal 1
When connected between 2 and 13, each electrode 10 and 11 and mover 1
A suction force Fh is exerted between 7 and 7 similarly to the above.

As a result, the mover 17 outside the electrodes 10 and 11 receives the attraction force Fh proportional to the square of the DC power supply V and is attracted into the electrodes 10 and 11.
At this time, by filling the liquid crystal 18 with each electrode 10,
11 and the movable element 17 can be maintained at a practically small value, the suction force Fh can be increased, and in addition, when the movable element 17 is moved by adhering the liquid crystals 19a and 19b. It is possible to reduce the frictional force Ff.

Therefore, the effective thrust Fa acting on the mover 17 can be increased. Thus, in the second embodiment,
The liquid crystal 18 is filled between the electrodes 10 and 11 and the mover 17, and the liquid crystal 19 is formed on each surface of the electrodes 10 and 11.
Since a and 19b are adhered or coated, the mover 1
Even if the electrodes 10 and 11 come into contact with each other when the electrode 7 moves, these electrodes 10 and 11 can be protected.

Further, the frictional force Ff when the mover 17 moves can be reduced and the effective thrust of the mover 17 can be increased. (4) Next, a third embodiment of the present invention will be described.

FIG. 13 is a block diagram of the electrostatic actuator. In the pair of electrodes 20 and 21 arranged to face each other,
The terminals 22 and 23 are connected to each other to form a capacitor. A switch 24 is connected to the terminals 22 and 23, and a DC power supply V is connected between the electrode 21 and the terminal 23.

The electrodes 20 and 21 are fixedly supported by the electrode supports 25 and 26, respectively. The spacers 2 having elasticity are provided on the edges of the electrode supports 25 and 26.
7 and 28 are provided so that the electrodes 20 and 21 are maintained with a predetermined gap therebetween.

Also, these electrodes 20, 21 and spacer 2
The space formed by 7 and 28 is filled with the liquid crystal 18 having a high relative permittivity εrc similar to the above-mentioned embodiments. The liquid crystal 18 is in the form of gel or liquid.

Next, the operation of the electrostatic actuator constructed as described above will be described. When the switch 24 is closed and a voltage is applied between the electrodes 20 and 21 to generate an electric field, the electrodes 20 and 21 in the upper state of FIG. 13 are attracted to each other by the attractive force Fv shown in the above formula (3). Try to meet.

Spacers 27 and 2 for supporting the electrode supports 25 and 26 by the attraction force Fv as shown in the lower part of the figure.
8 is deformed to a position where the sum of the elastic reaction force and the load force balances the suction force Fv.

The electrodes 20, 21 move in response to the deformation of the spacers 27, 28. Therefore, these electrodes 2
It functions as an actuator by taking out the movement of 0 and 21, that is, the displacement.

Here, when the displacement stroke of the electrodes 20 and 21 is constant, the attraction force Fv increases by the same multiple as the relative permittivity εrc as compared with the case where the space between the electrodes 20 and 21 is filled with air. For example, if the relative permittivity εrc of the liquid crystal 18 is 10, the suction force Fv will be 10 times.

When the attraction force Fv is the same, the stroke can be set to a length that is 1/2 times the relative permittivity εrc of the liquid crystal 18. For example, if the relative permittivity εrc of the liquid crystal 18 is 10, the stroke becomes 3.16 times.

As described above, in the third embodiment,
Since the liquid crystal 18 having a high dielectric constant is filled between the electrodes 20 and 21, and the electrodes 20 and 21 are displaced by the suction force between the electrodes 20 and 21, the suction between the electrodes 20 and 21 is reduced. The power can be increased.

On the other hand, as described above, the electrostatic actuator in which the liquid crystal 18 having a high dielectric constant is filled between the electrodes 20 and 21 is used as a unit actuator, and a plurality of the unit actuators are laminated in the displacement direction to have a long stroke. An actuator may be configured.

With such a laminated electrostatic actuator, a stroke corresponding to the number of laminated layers can be obtained. For example, the number of laminated layers can be reduced to obtain the same stroke as compared with the case where air is filled. For example, if the relative permittivity εrc of the liquid crystal 18 is 10, the number of stacked layers can be reduced to about 1/3.

To increase the force, the unit actuators may be arranged in parallel, but in this case as well, the number of unit actuators can be reduced. For example, the liquid crystal 18
If the relative permittivity εrc of is 10, the number of integration is about 1/10.
You can (5) Next, a fourth embodiment of the present invention will be described.

FIG. 14 is a block diagram of an electrostatic actuator. The electrode support 30 having elasticity has a plurality of electrodes 31.
36 (first electrode group) are arranged at predetermined intervals.
Further, on the other elastic electrode support 37, a plurality of electrodes 38 to 43 (second electrode group) are arranged at predetermined positions at positions facing the respective electrodes 31 to 36. As a result, capacitors are formed by the electrode pairs 31 and 38, 32 and 39, ... 36 and 43, respectively.

Here, the other electrode support body 37 is formed to be remarkably thinner than the one electrode support body 30. Between the electrode supports 30 and 37, that is, between the electrodes 31 to 36 and the electrodes 38 to 43, the same gel-like or liquid crystal 18 as in the above embodiments is filled.

On the other electrode support 37, a mover 44 is provided.
Is placed. The mover 44 includes an electrode support 3
The force S is applied in advance in a direction perpendicular to the contact surface by some mechanism so that a strong frictional force is generated between the contact surface 7 and the contact surface 7.

The energizing device 45 includes electrode pairs 31 and 38, 3 and 3.
2 and 39, ... 36 and 43 are selectively energized,
Here, each electrode pair 31 and 38, 32 and 39, ... 36 and 4
It has a function of sequentially energizing in the order of 3 and repeating this.

Next, the operation of the electrostatic actuator constructed as described above will be described. The energizing device 45 sequentially energizes the electrode pairs 31 and 38, 32 and 39, ... 36 and 43 in this order.

By this energization, each electrode pair 31 and 38, 32
, 39, ... 36 and 43 in this order, the suction force acts, and each electrode 3
8 to 43 are attracted to the corresponding electrodes 31 to 36, respectively. As a result, each electrode pair 31 and 38, 32 and 3
The distance between the electrodes becomes shorter in the order of 9, ... 36 and 43.

As a result, the electrode support 37 is connected to each electrode 3
It deforms in response to the displacement of 8 to 43, and the deformed portion moves in a wavy shape. Therefore, the mover 44 moves in the direction opposite to the wavy movement direction of the electrode support 37 as shown in the first to third states. By taking out the movement of the mover 44, it functions as an actuator.

As described above, in the fourth embodiment, the liquid crystal 18 having a high relative dielectric constant is filled between the electrode pairs 31 and 38, 32 and 39, ...
36, 43 are sequentially energized, and in response to the displacement of each electrode pair at this time, a wavy movement is generated in the electrode support body 37 to move the mover 44. The wavy movement force can be increased by increasing the attraction force at each electrode pair 31, 38, 32, 39, ... 36, 43.

Here, when the moving distance between the electrodes is constant, that is, when the amplitude of the electrode support 37 is constant, each electrode pair 3
Compared with the case where the space between 1 and 38, 32 and 39, ... 36 and 43 is filled with air, the suction force increases by the same multiple as the relative permittivity εrc. For example, if the relative permittivity εrc of the liquid crystal 18 is 10, the suction force will be 10 times. Therefore,
The driving force can be increased accordingly. (6) Next, a fifth embodiment of the present invention will be described.

FIG. 15 is a block diagram of an electrostatic actuator. The pair of coil electrodes 50 and 51 are coated with insulating films 52 and 53, respectively, and are adhered to each other. As a result, the pair of coil electrodes 50, 51 form a capacitor.

The pair of coil-shaped electrodes 50, 51 are formed of an elastic member and usually have a coil shape having a predetermined coil pitch. A DC power supply V is connected to the coil electrodes 50 and 51 via a switch 54.

A space between the coil pitches of the pair of coil-shaped electrodes 50, 51 is filled with a gel-like or liquid-state liquid crystal 18 as in the above-mentioned embodiments. Next, the operation of the electrostatic actuator configured as described above will be described.

When the switch 54 is closed, the DC power supply V is connected between the pair of coil-shaped electrodes 50 and 51, and an electric field is generated between these coil-shaped electrodes 50 and 51. Then,
The coiled electrodes 50 and 51 in the state of FIG. 15 try to approach each other due to the attraction force Fv expressed by the above formula (3).

By this attraction force Fv, each coil-shaped electrode 5
0, 51 itself is deformed, and these coiled electrodes 50, 51
Moves to a position where the sum of the elastic reaction force and the load force balances the suction force Fv, as shown in FIG. Note that FIG.
At 6, the coiled electrodes 50 and 51 move until they come into close contact with each other.

Therefore, by taking out the displacement of the coiled electrodes 50, 51, it functions as an actuator. As described above, in the fifth embodiment, the liquid crystal 18 having a high relative permittivity is filled between the coil pitches of the pair of coil-shaped electrodes 50 and 51 to energize the liquid crystal 18, so that the liquid crystal 18 increases suction. The displacement of each coil-shaped electrode 50, 51 due to the force can be taken out.

When the stroke (coil pitch) is constant, the attraction force Fv increases by the same multiple of the relative permittivity εrc as compared with the case where the space between the pair of coil electrodes 50, 51 is filled with air. For example, if the relative permittivity εrc of the liquid crystal 18 is 10, the suction force Fv will be 10 times.

When the attraction force Fv is the same, the stroke (coil pitch) is 1 of the relative permittivity εrc of the liquid crystal 18.
The length can be doubled. For example, the liquid crystal 18
If the relative permittivity εrc of is 10, the stroke is 3.16.
Doubled. (7) Next, a sixth embodiment of the present invention will be described.

FIG. 17 is a block diagram of an electrostatic actuator. On the electrode support 60, a plurality of electrodes are arranged at a predetermined interval to form an electrode group 61. This electrode group 61
Each of the switches forming the switch group 62 is connected to each of the electrodes. And these switches
Commonly connected to the DC power supply V.

In the switch group 62, each switch is selectively controlled to be switched by the energizing device 63, for example, the switch is controlled by scanning in either the left or right direction in the drawing.

A film electrode 65 is placed on the electrode group 61 with an insulating film 64 interposed therebetween in a shape in which the deformed portions 65a and 65b are formed in advance. Therefore, the electrode group 61 and the film electrode 65 form a capacitor.

Further, the space between the electrode group 61 and the film electrode 65 and the periphery of the film electrode 65 are filled with the same gel or liquid crystal 18 as in each of the above embodiments. Next, the operation of the electrostatic actuator configured as described above will be described.

When a desired switch is selected from the switches of the switch group 62 by the energizing device 63 and connected to the DC power source V side, the electrode corresponding to the switch and the film electrode 65 are connected.
A voltage is applied between the two and an electric field is generated, and the film electrodes 65 in that part try to attract each other by the attractive force Fv shown in the above formula (3).

The film-like electrode 65 is deformed by the attraction force Fv and moves to a position where the sum of the elastic reaction force and the load force balances with the attraction force Fv, or the film electrode 65 is attracted to the electrode 61. As a result, when each electrode of the electrode group 61 that connects the DC power source V is sequentially scanned, the portion of the film electrode 65 that is adsorbed by the electrode 61 also sequentially moves, and the deformed portions 65 a and 65 of the film electrode 65 are sequentially moved.
b also moves sequentially.

Therefore, it is possible to function as an electrostatic actuator by taking out the movement of the deforming portions 65a and 65b. As described above, in the sixth embodiment, when electricity is applied between the electrode group 61 and the film electrode 65, the film electrode 65 is deformed by the suction force increased by the liquid crystal 18 between the electrode group 61 and the electrode group 61. Since the portions 65a and 65b are moved, the movement of the deformed portions 65a and 65b of the film electrode 65 can be taken out by the suction force increased by the liquid crystal 18.

In this case, the relative permittivity εrc is higher than that in the case where the space between the electrode group 61 and the film electrode 65 is filled with air.
And the suction force Fv increases by the same multiple. For example, liquid crystal 1
If the relative permittivity εrc of 8 is 10, the attractive force Fv will be 10 times. Therefore, the film electrode 65 having a stronger elastic reaction force can be used, and a stronger output can be obtained. (8) Next, a seventh embodiment of the present invention will be described.

FIG. 18 is a block diagram of an electrostatic actuator. A first electrode group 7 in which a plurality of electrodes are arranged at predetermined intervals on each of the electrode supports 70 and 71 arranged to face each other.
2. The second electrode group 73 is fixedly supported. The electrodes in the first electrode group 72 and the second electrode group 73 are arranged to face each other.

The first electrode group 72 and the second electrode group 7
3 are commonly connected to each other and connected to the DC power supply V. The switches are connected between the switches of the second electrode group 73 and the DC power source V to form a switch group 74.

The energization device 75 has a function of selectively opening / closing each switch of the switch group 74, for example, controlling the opening / closing by scanning in either the left or right direction in the drawing. The space between the first electrode group 72 and the second electrode group 73 is filled with the same gel-like or liquid crystal 18 as in the above-described embodiments.

In addition, the first electrode group 72 and the second electrode group 73
A movable element 76 filled with the liquid crystal 18 is disposed between and. The mover 76 is made of a polymer material that deforms in an electric field.

Next, the operation of the electrostatic actuator configured as described above will be described. When the switch closed by the energization device 75 is a switch corresponding to each electrode in the vicinity of the mover 76 among the electrodes of the first and second electrode groups 72, 73, a voltage is applied between the electrodes and an electric field is generated. As a result, the direction of deformation of the mover 76 changes depending on the direction of the electric flux.

Therefore, the switch group 74 is controlled to open and close according to the position of the mover 76, and the first and second electrode groups 72,
When the polarity of each electrode of 73 is changed, the mover 76 repeatedly bends and deforms in both directions according to the polarity, and the liquid crystal 1
It receives reaction force from 8 and moves forward while curving.

By taking out the movement of the mover 76, it can function as an electrostatic actuator. Thus, in the seventh embodiment, the first and second electrode groups 72, 73 are
The movable element 76 made of a polymer material is selectively energized with respect to
Is moved, the movable element 76 can be deformed and moved by the suction force increased by the liquid crystal 18.

By the way, the electric flux density cannot be increased to such an extent that the mover 76 moves in a normal dielectric liquid or a liquid having a low dielectric constant. Therefore,
Usually, it is performed in water having a high relative dielectric constant, but there are problems such as electrolysis and large current consumption. However, when water is replaced by the liquid crystal 18 as described above, a high insulating property can be obtained, the current consumption can be drastically reduced, and a high voltage can be applied, and a more stable operation can be performed. (9) The effects produced by the electrostatic actuator of the present invention can be summarized from the above-described embodiments as follows.

Since the space in which an electric field is formed by two or more electrodes is filled with a liquid or gel liquid crystal having a high relative dielectric constant, the capacity of the capacitor formed by the stator electrode and the mover is increased. It is possible to dramatically increase the suction force to the mover.

By forming a thin film of gel-like or liquid crystal between each electrode pair and the mover, the gap between the electrode and the mover can be made to have an appropriate size. This makes it possible to manufacture an actuator on a relatively large scale and obtain an actuator that can move a long stroke.

Further, by inserting a lubricating solid, liquid or gel between the electrode and the mover, the frictional force generated between them can be reduced. Further, in the actuator of the type that uses the attractive force between the electrodes, a large stroke can be taken in one drive unit, and the stroke per unit length can be increased. This makes it possible to generate a large force when the stroke is the same as the conventional one.

Although some alcohol-based liquids have a high relative dielectric constant, they are highly flammable, and there is a risk of fire or explosion when a high voltage is applied. In addition, water, which is known as a liquid with an extremely high relative permittivity, has a relatively small resistance and has a problem with insulation, and also needs to be driven by alternating current in order to avoid electrolysis, and energy loss tends to be large. .

However, since the liquid crystal has a high insulating property and there is no fear of electrolysis, such a problem can be solved at once. When the above effects are combined, the effective output of the electrostatic actuator can be significantly increased by using the liquid crystal, and the output / volume ratio and the output / weight ratio can be increased.

[0122]

As described above in detail, according to the present invention, it is possible to provide the electrostatic actuator capable of significantly increasing the effective output.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of an electrostatic actuator according to the present invention.

FIG. 2 is a view for explaining the principle of the electrostatic actuator.

FIG. 3 is a diagram for explaining a suction force between electrodes.

FIG. 4 is a diagram for explaining an attraction force between the electrodes.

FIG. 5 is a diagram for explaining an attraction force between electrodes without a mover.

FIG. 6 is a diagram for explaining an attraction force between electrodes without the mover.

FIG. 7 is a configuration diagram showing a first embodiment of an electrostatic actuator according to the present invention.

FIG. 8 is a configuration diagram showing a first embodiment of the electrostatic actuator.

FIG. 9 is a diagram showing a change in thrust with respect to relative dielectric constant of liquid crystal.

FIG. 10 is a diagram showing a rate of increase in thrust with respect to relative dielectric constant of liquid crystal.

FIG. 11 is a configuration diagram showing a second embodiment of the electrostatic actuator according to the present invention.

FIG. 12 is a configuration diagram showing a second embodiment of the electrostatic actuator.

FIG. 13 is a configuration diagram showing a third embodiment of an electrostatic actuator according to the present invention.

FIG. 14 is a configuration diagram showing a fourth embodiment of an electrostatic actuator according to the present invention.

FIG. 15 is a configuration diagram showing a fifth embodiment of an electrostatic actuator according to the present invention.

FIG. 16 is a diagram showing a displacement state of the electrostatic actuator.

FIG. 17 is a configuration diagram showing a sixth embodiment of an electrostatic actuator according to the present invention.

FIG. 18 is a configuration diagram showing a seventh embodiment of an electrostatic actuator according to the present invention.

[Explanation of symbols]

10, 11, 20, 21 ... Electrode, 17, 44, 76 ... Mover, 18 ... Liquid crystal, 19a, 19b ... Protective liquid crystal, 25, 26, 30, 37, 60, 70, 71 ... Electrode support , 27, 28 ... Spacers, 31-36, 72 ... First electrode group, 38-43, 73 ... Second electrode group, 45, 63, 75 ... Energizing device, 50, 51 ... Coil-shaped electrode, 52, 53 ... Insulating film, 61 ... Electrode group, 62,74 ... Switch group, 65 ... Membrane electrode.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-285478 (JP, A) JP-A-4-207981 (JP, A) JP-A-3-5720 (JP, A) JP-A-1- 186178 (JP, A) JP 5-344753 (JP, A) JP 5-276766 (JP, A) JP 3-164073 (JP, A) JP 6-46584 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02N 1/00 H02N 11/00

Claims (12)

(57) [Claims] 1. An electrostatic actuator comprising at least two electrodes facing each other and a mover, wherein a high relative dielectric constant liquid crystal is filled between the electrodes, and the high relative dielectric constant liquid crystal is further provided on a surface of the electrode. A protective film made of a polymerized liquid crystal having a higher relative dielectric constant is formed, and a thrust force is exerted on the mover by applying an electrostatic field between the electrodes. Actuator. 2. The electrostatic actuator according to claim 1, wherein the liquid crystal has a relative permittivity corresponding to a gap between each electrode and the mover so that a thrust acting on the mover has a predetermined value. 3. The electrostatic actuator according to claim 1, wherein the thrust force displaces a gap between the two electrodes by an attractive force between at least two electrodes facing each other. 4. The electrostatic actuator according to claim 1, comprising two electrodes, at least one of which is a group of electrodes. 5. The electrostatic actuator according to claim 4, wherein the other electrode is a film-shaped electrode having elasticity. 6. A plurality of unit actuators for filling a liquid crystal having a high relative dielectric constant between the electrodes arranged to face each other to generate an attractive force between these electrodes, and stacking the unit actuators in a displacement direction. The electrostatic actuator according to any one of claims 1 to 3, characterized in that: 7. A fixed first electrode group, an electrode support having elasticity, and a second electrode group arranged at a position corresponding to the first electrode group with respect to the electrode support. , At least the liquid crystal having a high relative permittivity filled between the first and second electrode groups, the mover mounted on the electrode support, and the first and second electrode groups. The electrostatic actuator according to claim 1, further comprising an energizing unit that selectively energizes. 8. A pair of coil-shaped electrodes adhered to each other via an insulating film, a liquid crystal having a high relative permittivity satisfying a coil pitch between the coil-shaped electrodes, and an energizing means for energizing the coil-shaped electrodes. The electrostatic actuator according to claim 1, further comprising: 9. An electrode group in which a plurality of electrodes are arranged, a film-shaped electrode having elasticity arranged on the electrode group via an insulating film, and at least between the electrode group and the film-shaped electrode. The static liquid crystal display device according to claim 1, further comprising: a filled liquid crystal having a high relative dielectric constant and an energizing unit that selectively energizes between the film electrode and each electrode of the electrode group. Electric actuator. 10. A first electrode group in which a plurality of electrodes are arranged, a second electrode group including a plurality of electrodes arranged to face the first electrode group, and the first and second electrode groups. A movable element made of a polymer material which is arranged between the electrode group and deforms when an electric field is applied, and a liquid crystal having a high relative dielectric constant filled between the first and second electrode groups. The electrostatic actuator according to claim 1, wherein: 11. The electrostatic actuator according to claim 1, wherein the liquid crystal is liquid or gel. 12. The electrostatic actuator according to claim 1, wherein the liquid crystal has a nematic phase or a cholesteric phase.