JPH0232768A - Electrostatic motor - Google Patents

Abstract

PURPOSE:To reduce the frictional force of an apparatus and to improve the efficiency thereof by arranging a Langmuir-Blodgett film between the surface of a dielectric film to be given between electrodes on a stator based and an electrode surface on the rotor side. CONSTITUTION:An electrostatic motor is composed of a stator 20 and a rotor 30. Said stator 20 is equipped with a stator base 21, an array electrode film 22, a dielectric film 23 and a Langmuir-Blodgett film (LB film) 24, and a lead wire is pulled out from each array electrode film 22 and connected with a terminal 25 according to the number of phases of said motor. In said rotor 30, the same kind of a base 31 as the stator base 21 is used and the other stripe electrode 32 is arranged on said base 31 to form the rotor 30. The end of said electrode 32 is provided with a sliding electrode 33, to which a lead wire is attached and connected with a terminal 35. Thus, said LB film 24 has low friction properties and can maintain said stator 20 and rotor 30 in a state where they are separated from each other.

Description

[Detailed Description of the Invention] [Prior Art] In recent years, there has been a demand for motors with various types such as low-speed/high-torque types, hollow types, and ultra-compact types, and the needs for motors have diversified. ing. In order to meet these needs, conventional electrode type motors are unable to meet the needs of the lateral base, and ultrasonic motors using piezoelectric elements have recently been proposed and are being developed. Ultrasonic motors have the following features compared to conventional electrode type motors.

1. Low speed and high torque are possible.

2. Great holding power.

3. Hollow type is possible.

4. Does not receive magnetic effects.

5. Can be made ultra-small.

Thus, it has been put to practical use, for example, as an actuator for opening the camera and positioning it.

FIG. 15 is a diagram showing the principle of an ultrasonic motor. A stator 1 has a piezoelectric element (not shown) bonded to an elastic body such as a metal plate,
A bending traveling wave is excited by applying a two-phase alternating current voltage to the piezoelectric element. As a result, each mass point P1, P2 on the surface of the stator 1 causes a backward elliptical movement as shown in the figure with respect to the traveling direction M1 of the traveling wave.As is clear from FIG. The sliding part 3 of
Contact with the apex of backward elliptical motion. The displacement directions of these contact points are all the same, and the rotor 2 that is in contact with the rotor 2 moves in the direction M2 opposite to the traveling direction of the traveling wave.

The rotor 2 moves in this way because the force generated by the piezoelectric element is applied to the frictional force at the interface between the stator 1 and the sliding portion 3 of the rotor 2.

Therefore, if the friction coefficient of the sliding member 3 is μ and the pressing force of the rotor 2 against the stator 1 is F, then a starting force of μ×F will be generated.

The above is the operating principle of the ultrasonic motor, and it has already been experimentally confirmed that the ultrasonic motor can exhibit the features 1 to 5 described above.

However, at the same time, some drawbacks are becoming increasingly apparent.

The first is that ultrasonic motors use resonant vibrations, so
If the Mf1J frequency and the motor's resonance frequency deviate, the motor characteristics will deteriorate rapidly.

Therefore, a means is needed to automatically make the drive frequency follow changes in the resonance frequency. This makes the drive circuit complicated.

The second reason is that the resonant vibration leaks to the side of the R supporting the resonator, making it impossible to increase the efficiency sufficiently and making it unusable in liquid.

Thirdly, in principle, it should be possible to increase μ×F in order to obtain high torque, but in reality there are restrictions and there is a limit to how high torque can be achieved. In other words, it has been found that μ is preferably 0.1 to 0.5 for existing materials due to durability constraints. Therefore, in order to obtain high torque, it is necessary to increase the pressing force F, but In order to increase the pressure F, it is also necessary to increase the bending displacement generating force by the piezoelectric element. For this reason, high voltage will be input,
Lead zirconate titanate (PZT), which is commonly used and has a large piezoelectric constant, is a ferroelectric material, and its spontaneous polarization depolarizes, deteriorating the performance of the motor. In addition, the bending displacement generating force is a conversion of the stretching vibration of the piezoelectric element bonded to the elastic body, so the same force acts on the bonding surface, which is similar to the bonding force between the piezoelectric element and the metal elastic body. When force is generated, delamination may begin to occur. Therefore, in the end, a very large pressing force cannot be applied, and there is a limit to how high torque can be achieved.

Fourth, since ultrasonic waves are dispersed in all directions and leak in liquid, there is a drawback that the ultrasonic motor does not operate efficiently.

The present inventors have been searching for a motor with another structure that eliminates the drawbacks of the ultrasonic motor and has the advantages of the ultrasonic motor. It has been found that electrostatic motors, which have recently begun to be announced little by little, and in particular, electrostatic motors that are becoming increasingly miniaturized, have the potential to meet the requirements. Therefore, the present inventors have focused on electrostatic motors and have conducted extensive research. Electrostatic motors use electrostatic charge attraction force, and the content was presented at the 14th Tokyo Institute of Technology Symposium.
It is explained in detail in ``Recent Actuators and Their Trends''.

FIG. 16 is a diagram showing the principle of a conventional electrostatic motor. As shown in FIG.
Electrostatic force is generated along the plane direction of and 5. An electrostatic motor is designed to utilize this electrostatic force.9 The generated electrostatic force is proportional to the dielectric constant of the dielectric sandwiched between the electrode plates 4.5 and the square of the applied voltage V. Such an electrode plate 4
．． An electrostatic linear motor or an electrostatic circuit type motor can be obtained by arranging a large number of motors 5 along the moving direction and driving them in multiple phases.

Electrostatic micro actuators using electrostatic motors as their driving source have only recently attracted attention as microfabrication technology has progressed. The principle is shown in Figure 16 and 1.
This will be explained using FIG. Parallel electrode plate 4 shown in FIG.
The capacitance C in the structure with 5 is as follows.

C=εQεrxQ/Z ε0: Dielectric constant of vacuum εr: Relative dielectric constant The electrostatic energy We that can be stored is as follows.

We CV2/2 ■: Using the applied voltage virtual displacement method, the force FX in the X direction acting on the electrode is FX = (lWa 1X) Constant = V2J/2c)x・ (εo xQ, /Z) ==■
2 ε0 sr λ/2Z・・・・・・・・・・・・
(1) Therefore, FX does not depend on the overlap width X, and
The smaller the inter-electrode distance 2, the greater the inter-electrode attractive force in the X direction. Similarly, the force FZ in the Z direction acting on the electrode is obtained from the virtual displacement method as follows.

FZ (=lWe/Fz)v constant=V2)/2')Z (εOsr x9./z)=-V
2 εOsr xg/2z”−・−(2) In this case, x
; It means that the larger LL is, the larger the inter-electrode attractive force is.

By reducing 2 from the above two equations to make the device compact, the stored energy per unit volume can be increased. However, what is shown in Fig. 16 is one basic element of a dynamic drive source, and when actually moving each other over a long distance, the
As shown in the figure, it is necessary to arrange a large number of the basic elements described above.

In Fig. 17, 4S indicates a stator, and 5R indicates a rotor. In Fig. 0, the shaded part 8 is an electrode part;
A portion 9 that is not shaded is a portion to which no electrode is attached. The rotor side electrode portions 8 have a width W and are arranged at equal intervals. Further, the width of the interval 9 is also W. The electrode part 8 on the stator side has a width of W as above, but the width is 1!
The width of the distance 9 from the pole is 4W/3.

Now, in the same figure, when a voltage is applied to AA', CC', and KE, the stator 4S moves in the X direction relative to the rotor 5R, and when a voltage is applied to BB', DD'EE', the stator 4S moves in the X direction relative to the rotor 5R. Move in the opposite direction.

Next, the voltage applied to the instantaneous question AA' where AA- matches is off.
f, and a new voltage is applied between DE'.

Furthermore, at the moment when CC' matches, the voltage application to CC' is stopped and a new voltage is applied to BD'. If this operation is repeated over 0, the rotor 5R will continuously move in one direction. Become.

FIG. 18 is a diagram showing a rotary actuator. This is a striped electrode 11 buried in an insulating thin MIO.
And insulation 11! It consists of a cylindrical electrode 12 placed on top of the io. The striped electrode 11 is connected to the power supply pad 13, and the circular frJ electrode 12 is electrically conductive to the ground electrode 14. Now, when the position of the cylindrical electrode 12 is detected by the position detection electrode 15 and a voltage is applied from the power supply pad 13 to the striped electrode 11 according to the detected position, a static voltage is generated between the cylindrical pole 12 and the striped 44 poles 11. 0 cylindrical type where electric attraction works [
As the electrode 112 rotates due to electrostatic force, the rotation of the cylindrical electrode 12 is maintained by sequentially switching the electrodes to which voltage is applied. The actuator of this structure requires that the cylindrical electrode 12, which is a moving body, perform rolling motion, and that it is necessary to sequentially switch the power supply to the power supply pads 13 according to the movement of the cylindrical electrode 12. Since an air layer enters the portion immediately before the electrode 12 makes contact, there are problems such as a limit to the suction force.

[Problem to be solved by the invention]

The electrostatic attraction to be utilized in the present invention uses the FX shown in equation (1), and many of the arranged electrodes are used at the same time, so a rotary actuator as shown in FIG. There are no drawbacks, and a large driving force can be obtained.

By the way, when the electrostatic attraction force Fx is used, the electrostatic attraction force FZ generated at the same time causes frictional force to be generated between the stator and the moving element. A certain amount of electrostatic attraction FZ serves as a holding force to fix the relative positions of the stator and mover, and since this electrostatic attraction FZ can be secured with a small amount of electric power, it is better to leave it. That is, since the above-mentioned holding force is achieved by applying a DC voltage to a capacitor having a large insulation resistance, it is possible to consume almost no power. Therefore, it is possible to obtain a holding force as large as that of an ultrasonic motor using the electrostatic attractive force Fz. However, if the holding force is increased to a certain extent, the frictional force between the stator and the moving element also increases, causing a problem of increased loss.

Therefore, an object of the present invention is to provide an electrostatic motor that fully has the characteristics of an ultrasonic motor, has a small frictional force between a stator and a moving element, and can be expected to operate efficiently. Our goal is to provide the following.

[Means for Solving the Problems] The present invention has taken the following measures in order to solve the above problems and achieve the objects.

(1) A stator, stator electrodes provided in stripes at predetermined intervals on one surface of the stator, a mover disposed to face the stator, and stator electrodes provided at intervals different from the intervals between the stator electrodes. Separation holding means for holding the stator and the mover in a separated state so that the mover electrodes provided in stripes on the surface of the mover facing the stator do not come into direct contact with the stator electrodes and the mover electrodes. I made sure to prepare the following.

(2) A stator, stator electrodes provided in stripes at equal intervals on one surface of the stator, a dielectric thin film provided on the stator with the stator electrodes in between, and a dielectric thin film provided opposite the stator. a mover electrode provided in stripes on a surface facing the stator of the mover so as to have electrodes that do not completely overlap each other with the stator electrode; A frictional force damping means is provided between the insulation and the body thin film.

(3) In the electrostatic motor according to claim 1, the separation holding means is made of an LB film (Langmuir-Blodgett M) having low friction properties.

[Effect]

By taking such measures, the frictional force between the stator and the moving element is reduced, making it possible to achieve the above object.

〔Example〕

"Example A" Example A of the present invention will be described below, but before giving a specific explanation, the gist of this example will be explained.

In this embodiment, as a means for reducing frictional force,
A feature is that an LB film, that is, a Langmuir-Blodgett film, is formed at the interface between the stator and the rotor as a moving element. That is, the LBW is applied to either or both of the stator side surface or the rotor side surface.
! The purpose of this is to grant the following. LB such as stearic acid
The fact that llg is a film with a low coefficient of friction that has a boundary lubrication effect is shown in the literature [Applied Physics 55 [6] 1986. p
As described in pages 615 to 617J, this is well known, and its application to, for example, the surface lubricating film of high-density magnetic recording disks is being considered. When LBWA stearate is formed, for example, on a clean Cu surface, the coefficient of friction was 1.1 before film formation, but it is reduced to 0.3 just by forming a monomolecular layer. As the cumulative number of layers increases, the friction coefficient gradually decreases, and when the cumulative number of layers is 27, it becomes a very small value of 0.04. By interposing a film with such a small coefficient of friction, even if electrostatic attraction is applied in a direction perpendicular to the electrode surface, the resulting frictional force can be significantly reduced.

For example, the electrode width Q <=5 mm), the length of the overlapping part of the electrodes x (=10 μm), and the thickness of the dielectric film between the electrodes z (=
1 μm), relative permittivity εr = 1000>, applied voltage V
(100V), the electrostatic attractive force FZ and t[! in the direction perpendicular to the electrode surface. The electrostatic attractive force FX in the direction horizontal to the plane is as follows.

Fz =V250 εr xffi/2z2=2.2N FX =V2εo εr g/2z =2.2X10N When having the above structure, the frictional force is μ・FZ (μ is!
s! If μ≧0.1, the rotor will not move. Note that the above conditions correspond to the above dimensions and structure; for example, when z = 2 μm, Fz = 0.55N, Fx = 0.11N,
μ≧0.2. Also, the area where the electrodes overlap is 5 μm.
Then, FZ=1, IN, Fx=0.22N, and μ≧0.2. Combining the above two conditions, FZ = 0.275N, Fx = 0.1 IN, μ≧
A condition of 0.4 is required. However, as can be seen from these calculations, II! As the condition becomes such that the coefficient of friction may be large, Fx, that is, the driving force of the motor decreases. Therefore, in order to obtain a large driving force as a motor, a lubricating film with as low a filtration coefficient as possible is required. LB films are characterized not only by their low coefficient of friction, but also by the fact that they can be formed into extremely thin films and have the potential to form films with high dielectric constants.

In particular, making the film extremely thin and increasing the dielectric constant has a great effect on the output characteristics as seen from the above calculation formula, so it can be seen that the effect of using the LB film is great.

A specific example will be explained below.

FIGS. 1A and 1B are diagrams showing a first specific example in Example A. Figure 1(a) shows the stem 20 and rotor 3.
FIG. 1(b) is a cross-sectional view showing only the right half. The stator 20 is composed of two array electrodes M422 such as the stator substrate 21, a dielectric film 23, and an LB film 24. The array electrodes W422 are grouped into several groups according to the number of phases of the motor, and leads from each. A wire is drawn out and connected to the terminal 25.

The stator substrate 21 is made of high-density ceramics such as alumina or zirconia silicon nitride, ceramics made of lead zirconium titanate (PZT) or lead zirconium titanate (PLZT) sintered with high density by hot pressing, sapphire, or oxidized ceramics. Any of short crystals such as magnesium, glass such as fused silica glass, or a silicon substrate with an oxide film formed on the surface may be used. This is processed into a donut shape as shown in FIG. 1<a) to form the substrate 21. The surface is polished to a mirror finish to keep it clean. Next, on the surface of this substrate 21, chromium, nira gel, gold platinum, silver, etc. are applied independently using a sputtering method.
Alternatively, the array electrode film 22 is formed on the entire surface with a two-layer structure using chromium as the base. After forming this electrode, in order to improve the adhesion with the substrate 21, a heat treatment is performed as necessary, and then a high dielectric material is formed using a sputtering method or a sol-gel method. ! 1K
For example, PZT! by the sol-gel method. When forming I, a 0.2 μm thick layer of chromium is used as a base layer on a zirconia substrate by sputtering, and platinum is deposited by electron beam evaporation thereon to a thickness of 0.2 μm.

Next, a general photorin process is used to form the desired electrode pattern. On the stator substrate 21 on which such an electrode pattern is not formed, a solution in which lead acetate is thoroughly mixed with a propoxy compound of zirconium and titanium in methoxyethanol is dropped, and a film is formed using a spinner.

Then, it is heated to 400 to 700°C using an infrared lamp.

In this way, the coating film using a spinner and the heat treatment are alternately performed, and the process is repeated several times to T&10 times, and the treatment is stopped when the target thickness is reached. Then, this substrate is reheated by removing heat. After careful heat treatment in this way, LBl124 is attached.

LBrFA24 is stearic acid and 1. This is stacked in a Y shape to form a #I structure with 5 to 30 layers. One layer of stearic acid is 2.55 m thick, so the thickness of 10 layers is 25.5 m Stearic acid was used in the 6 experimental examples, but if it is a molecule with lubricating properties, stearic acid LBJM124 is made by alternately accumulating two different types of molecules, and it is possible to 'It'A' or modify a part of the molecule, so it has a large dielectric constant. There is a high possibility of obtaining LBJII, and it has good lubricity.
Moreover, LBwA with a large dielectric constant can be obtained6.For example, a fluorine-containing LB film has excellent lubricity and insulation properties, and can uniformly form films for 5 to 100 people in one layer (
The stator 20 is created in the manner described above (Nikkan Kozo Shimbun s63.6.14).

The rotor 30 uses a standard 31 of the same type as the stator substrate 21, on which the other striped electrodes 32 are arranged. The edge of the stripe electrode 32 has a sliding type f! 33 is provided with its tip in sliding contact, and this sliding electrode 3
A lead wire is attached to 3 and connected to a terminal 35.

A power supply voltage V is applied between the terminal 25 and the terminal 35. As will be described later, the stripes 32 attached to the rotor 30 are arranged at regular intervals, and all are commonly connected and grounded. This grounding may be done via a metal ball bearing attached to the rotor 30, or a sliding electrical terminal for grounding may be provided and the grounding may be done via this terminal.

In this embodiment, the rotor substrate 31 is made of the same material as the stator substrate 21, but the substrate does not necessarily have to be made of the same material.

FIG. 2 is a diagram schematically showing the arrangement of stripe electrodes on the rotor 3o and the stator 20 when viewed from the rotor side of the ring-shaped electrostatic motor shown in FIGS. 1(a) and 1(b).

As shown in FIG. 2, both the stator and the mover are made up of six electrode arrangement groups. The amount of deviation between the stator electrodes and the mover electrodes in each group is all the same. That is, in FIG. 2, there is no deviation between the stator electrode and the movable element electrode in the portion A1, the deviation by 1w/3 in the portion A2, and by 2w/3 in the portion A3.

Therefore, in Fig. 2, - voltage is applied to the rotor electrode (solid line), and among the stator electrodes (dotted line) A2, A3, A4
When a + voltage is applied to the group, the rotor rotates in the direction of the arrow in the figure. Also, add + to groups A4, A5, and A6.
When voltage is applied, it rotates in the opposite direction. Incidentally, if the A4 group is arranged as is with respect to the rotor, the electrostatic force in the circumferential direction will not work.

However, if the rotor begins to rotate even slightly, a force will be generated in the direction of rotation.

Now, as shown in Fig. 2, when + voltage is applied to the groups A2, A3, and A4 (in the state shown in Fig. 3), the rotor rotates in the direction of the arrow in the figure, but the electrodes of the A2 group , once overlapped with rotor electrodes R4, R5, and R6, the voltage of A2 must be returned to 0 because it becomes a force that suppresses rotation. Instead, just apply a new + voltage to A5 (state of ■ in Figure 3), like this, AI, A2...
By sequentially switching the timing of applying + voltage to A6, the rotor will rotate.

FIG. 4 is a diagram showing the above timing. In the same figure, ~■ is one period of voltage application, and in that one period,
As shown in Figure 2, when the number of rotor electrodes is 018, (360/
18) = 20° rotation. As can be seen from FIG. 4, the timing of applying voltage to A1, A2, . . . A6 is shifted by six cycles per layer.

The circuit that supplies this kind of voltage is not particularly difficult;
It is obtained by amplifying the output of an ordinary digital circuit.

FIG. 5 is a diagram showing a second specific example in Example B. The feature of the 0-wire structure is that an LB film is applied to the rotor side. The rotor side electrode 32 shown in the first specific example is in an exposed state. Even if the electrode 32 is exposed in this way, there is no problem as long as the electrode 32 is firmly attached to the substrate 31 and a metal that is stable against corrosion, such as platinum or palladium, is used. However, these stable metals are expensive, and it is difficult in terms of production technology to always maintain the adhesion of several thousand striped electrodes without any peeling.

Therefore, in this example, as shown in FIG. 5, an LBM 34 is provided on the rotor side so as to coat the electrode 32. In this way, problems caused by electrode exposure can be solved. However, since the thickness of the electrode 32 is about one order of magnitude thicker than the thickness of the LB film 34, a step structure corresponding to the thickness of the electrode 32 is formed with respect to the surface of the substrate 31. Due to this step, it may not be possible to obtain a clean LBWA surface. Also, LB at the step part
Membrane Type 4: The film may peel off easily or be easily scratched. In order to eliminate such problems, the rotor 30 may be structured as shown below.

First, alumina ceramics having a thickness of 0.65 ta is prepared as the substrate 31, and one side is mirror-polished. Gold, aluminum, etc. are formed on the entire surface by sputtering to a thickness of 1 μm or more. Then, using photolithography techniques,
Etch the desired pattern. Then, this is coated with a resin such as polyimide to a thickness of t4Ii or more.

The coating may be applied by any means such as spin cord, spray, dip, etc. Alternatively, a method of vacuum-depositing parylene may be used. In this way, the resin such as polyimide or parylene will adhere to both the electrode part and the non-electrode part.
The electrode part has a raised shape. After the coated resin is sufficiently heated and cured, polish it using a precision polishing method such as float polishing until the electrode metal part is exposed. Because of the above thickness, this polishing makes the electrode surface and the surface where there is no electrode a continuous surface with no difference in level.

After doing this, as in the case of the first example, the LBI
Ii is formed over the entire surface to a thickness of several tens of μm. L
The BJIM is formed in a Y-shaped stack so that the polarity in the direction perpendicular to the film surface is as large as possible.

FIG. 6 is a diagram showing a rotor structure according to this example in which the above-described measures are taken. FIG. 6 is a view of FIG. 5 viewed from the outside in the radial direction. As shown in the figure, resin 3 such as parylene or polyamide is used to fill the spaces between the poles 32 between the arranged stripes.
6 is given.

Note that the material filling the spaces between the stripe electrodes 32 is not limited to resins such as parylene and polyamide, but an insulating film such as 5i02 film or 12031 film may be applied by means such as sol-gel method.

According to Example A, since the LBWA was added between the surface of the dielectric film applied between the electrodes on the stator substrate of the electrostatic motor and the surface of the electrode on the rotor side, the rotor surface and the stator surface were Occurs between r! If the Jm force can be significantly reduced, an electrostatic motor with large output and high efficiency can be provided at low cost.

"Example B" Next, Example B of the present invention will be described, but before giving a specific description, the gist of Example B will be described.

In this embodiment, as a means for reducing the frictional force, a means was taken to substantially reduce the coefficient of friction. As a means for this, a means is used in which the moving element is slightly levitated relative to the stator.

The first means is to vibrate the stator ultrasonically in a direction perpendicular to the contact surface (in the Fz force direction) and levitate the movable element in contact with the stator.

Ultrasonic levitation is a technology that has already been put into practical use with guide rail stages.

As a second means, a means for levitating by magnetic repulsion is used. In this case, there are methods such as providing an electrode and a dielectric #% film on a ferromagnetic substrate, or forming a ferromagnetic ferromagnetic thin film on an insulating substrate and providing an electrode thereon.

As a third means, when used in liquid helium or liquid nitrogen, a means utilizing the superconducting Meissner effect is used.

All of the above three means reduce frictional force by floating, and can provide great durability.

In cases where financial stability is not required, it can also be achieved by applying a liquid or solid lubricant or a wear-resistant thin film coating.

In this case, there is an advantage that the structure is simple and inexpensive.

Example B will be specifically described below.

FIG. 7 shows the t-pole 42 showing the first specific example on the day of the example.
A high dielectric constant layer 43 and a sliding material 44 are attached. Further, the rotor 50 has an electric current 52 on the rotor base material 51.
A high dielectric constant layer 3 and a sliding material 54 are attached. The electrostatic attraction force acting in the thickness direction of the electrodes between the electrodes 42 and 52 is supported by the contact of the sliding members 44 and 54.

The sliding material 44.54 is, for example, a polyacetal or polyamide based oil-impregnated compound with μ of about 0.1, such as zirconium titanate (PZT) thin film, barium titanate thin film, titanium oxide thin film, aluminum nitride, tantalum pentoxide, etc. The high dielectric constant layers 43 and 53 are set so that they may or may not touch each other.

The electrodes 42.52 are coated with Cr, Au, Ni, etc. by sputtering or the like, and are coated with a high dielectric constant i43.53. The electrode pattern is, for example, as shown in FIG. Therefore, the lead wire is Al.

A2. ...A6. . . , one for each, and a common one for only the - side. Then, a fourth electrode is attached to each of these electrodes.
If voltage is applied at the timing shown in the figure, the rotor will rotate.

FIG. 8 is a side sectional view showing an outline of a second specific example applied to a linear electrostatic motor as shown in FIG. 17. The stator 60 has electrodes 62 and a high dielectric constant layer 63 provided on a stator substrate 61. Also slider 7
0 has a slider base material 71 provided with an electrode 72 and a high dielectric constant layer 73. The high dielectric constant layer 63 of the stator 6o and the high dielectric constant layer 73 of the slider 70 are arranged to face each other. Therefore, the electrode 62.
When a voltage is applied to the slider 72 at the timing described above, the slider 70 moves laterally.The force in the moving direction generated at this time is a combination of the attraction force acting in the direction perpendicular to the opposing surface and the friction coefficient. The following equation is derived from equations (1) and (2) above, which must be larger than the product of μ.

1>(μ・x/z) Now, if μ=0.1, then (x/z)<10...(3) is obtained. Therefore, if the dimensions satisfy the above formula (3), the slider 70 will slide. In this example, the stator 60 and the slider 70 are A minute gap shall be formed between the two. A specific example of forming minute voids will be described below.

FIGS. 9 and 10 are diagrams showing specific examples for forming microgaps. First, as shown in FIG. 9, the center of one side of a rectangular plate-shaped high-density PZT ceramic 80 sintered by hot pressing or the like is ultra-precision machined into a concave shape, and convex portions 80a are formed on both sides.

80b. and high-density PZT ceramics 80
Electrode plates 81 and 82 are pasted on the lower surface of.

Striped electrodes 91, 92, similar to the linear array type electrode shown in FIG. ...is provided by sputtering or plating. A high dielectric constant layer 90 made of PZT or the like is formed in the recessed portion by a sol-gel method or the like, and then the surface of this high dielectric constant layer 90 is polished to a smooth surface. And striped electric [1101
, 102, 103, . . . are embedded in the slider 1.
00 is formed and placed on the stator surface formed as described above. After doing this, the electrodes 91, 92 . ...
A high voltage is applied between the electrodes 81 and 82 to perform polarization processing.

FIG. 10 is a diagram showing the state after the above polarization process. As shown in FIG. 10, compared to the state before polarization shown in FIG. , the surface of the high dielectric constant layer 90 on the stator side and the slider 1
A gap layer 12 with a thickness of A2 is provided between the lower surface of the
0 is formed. Therefore, the stripe electrode 10
1102, . . . and electrodes 111, 112. The frictional force at the overlapped portion with ... disappears. In addition, when such a structure is adopted, the convex portion 80 where residual polarization 83.84 occurs
The slider 100 slides on the electrode portions formed on the tops of the electrodes a and 80b.

If wear caused by this sliding becomes a problem, it is sufficient to coat the electrode portion with a drag-resistant thin film such as titanium nitride or silicon nitride.In addition, in this example, the operation of polarizing the piezoelectric ceramics is Although necessary, once the polarization process is performed, there is no need for applied voltage thereafter.

FIGS. 11(a) and 11(b) are diagrams showing a third specific example of Example B. FIG. 11(a) is a partial cross-sectional view when not in operation, and FIG. 11(b) shows a momentary state during operation. In this example, piezoelectric ceramics are used as the stator base material 131, similarly to the second specific example. The difference from the second specific example is that the second specific example uses static deformation due to polarization, whereas in this example, after polarization, the electrodes 132, 13
An alternating current voltage is applied between 3 and ultrasonic wave 41i! ! 7, the rotor 140 is levitated, thereby forming a gap G and reducing the drag force. Note that the portion subjected to ultrasonic vibration is not limited to the peripheral portion, and the entire surface of the piezoelectric ceramic may be subjected to ultrasonic vibration.

FIG. 12 is a diagram showing a fourth specific example in Example B. This example is an example in which magnetic levitation is performed using a magnetized magnet with a large coercive force. As a stator, for example, Ba
After the surfaces of the ferrites 1 to 41 are polished, striped electrodes 152 are formed by sputtering, electron beam evaporation, etc. so that the electrodes are arranged as shown in FIG. After that, using sputtering or sol-gel method, PZT, B, etc. are used to prevent demagnetization.
A high dielectric constant thin film such as aTiO3 or PbTiO3 is formed. Further, as the rotor 160, a magnet with a large coercive force is used for the rotor base material 161, and the stator 150 and the rotor 160 are
Place the same poles facing each other so that they magnetically repel. or,
When using a rare-earth metal magnet as a magnet, a thin glass plate, crystallized glass, ceramics, or other thin film may be adhered to the surface, and electrodes or a high dielectric constant layer may be provided on the surface.

FIG. 13 is a diagram showing a fifth specific example in Example B. This example is an example of an electrostatic motor configured so that it can be used in liquid, and in particular, an example of an electrostatic motor that can be used even in an atmosphere of liquid helium temperature or liquid nitrogen temperature. The figure shows the electrostatic motor placed in liquid nitrogen. As the stator 150, a magnet 151 similar to the fourth specific example is used.
, and when the magnet 151 is an insulator,
If it has conductivity, an array of "f4 [f stripes 152
is formed, and a high dielectric constant layer 153 is further provided. On the other hand, the rotor 170 is made of high-temperature superconducting oxide that exhibits superconductivity in liquid nitrogen, such as YBa2Cu307-ceramics 171.
An insulating material 174 is pasted on the electrode 172. A high dielectric constant layer 173 is provided.

The superconducting ceramic 171 exhibits the Meissner effect below a critical temperature of 90, and is repelled by the magnetism of the magnet 151.

As a result, a repulsive force acts between stator 150 and rotor 170. This becomes a floating blade, and the I'l friction force decreases.

FIG. 14 is a diagram showing a sixth specific example in Example B. In this example, a powder with good lubricity such as MoS2 (molybdenum sulfide) is placed between the surface of the stator 180 and the surface of the rotor 190 200, and a lubricant such as grease is interposed thinly. .

In the above explanation, 1. The voltage application route to the electrodes was hardly mentioned, so it will be described below. First, A1, A2, etc. arranged on the stator side in Figs. 3 and 4.
...Six lead wires are connected to A6 to sequentially switch and input the voltage, and the rotor ■ is connected in parallel so that all electrodes have the same single pole, and after being led to the sliding electrode, the sliding spring terminal 5
5.

Also, in FIG. 9, all stator side electrodes 919-2.
For..., lead wires 111112,...
is the installation. The rotor side is the same as that shown in FIG. Third
Examples 1 to 6 have the same lead wire ratio as the first example (FIG. 7).

In addition, regarding the relative misalignment between the rotor and stator, since the electrostatic force is originally plowed in a direction that automatically eliminates the misalignment,
If you do not need a large motor torque, just cover it with a housing. If the torque output is required to the extent that the rotor will come off, a guide may be provided and a bolt may be inserted between the guide and the rotor to prevent the rotor from coming off.

In the rotary electrostatic motor of the present invention, the number of electrodes on the rotor side is 18, and the number of 4-pole groups on the stator side is 6.
However, the number is not limited to 1 and this combination.

As described above, according to Example B, since a means is provided to attenuate the frictional force expressed by the product of the attraction force acting in the direction perpendicular to the electrode surface and the friction increase coefficient by $4, the durability is good. We can provide a silent motor that provides stable rotation and movement.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an electrostatic motor that has the characteristics of an ultrasonic motor, can reduce the vibration force between the stator and the moving element, and can be expected to operate efficiently.

[Brief explanation of the drawing]

1(a), (b) to 6 are diagrams showing Embodiment A of the present invention, FIGS. 1(a), (b) to 4 are diagrams showing the first specific example, and FIG. The figure and FIG. 6 are diagrams showing a second specific example. 7 to 14 are diagrams showing Example B of the present invention,
FIG. 7 shows the first specific example, FIGS. 8 to 10 show the second specific example, FIGS. 11(a) and 11(b) show the third specific example, and FIGS. Figure 12 is a diagram showing the fourth specific example;
FIG. 3 is a diagram showing a fifth specific example, and FIG. 14 is a diagram showing a sixth specific example. FIGS. 15 to 18 are diagrams showing the prior art. Applicant's representative Patent attorney Jun Tsuboi Figure 1 (a) Figure 2 Figure 1 (b) Figure Figure 15 Figure 13 Figure 16 Figure 17

Claims (3)

[Claims] (1) A stator, stator electrodes provided in stripes at predetermined intervals on one surface of the stator, a mover disposed to face the stator, and stator electrodes provided at intervals different from the intervals between the stator electrodes. Separation holding means for holding the stator and the mover in a separated state so that the mover electrodes provided in stripes on the surface of the mover facing the stator do not come into direct contact with the stator electrodes and the mover electrodes. An electrostatic motor comprising: (2) A stator, stator electrodes provided in stripes at equal intervals on one surface of the stator, a dielectric thin film provided on the stator with the stator electrodes in between, and a dielectric thin film provided opposite the stator. a mover electrode provided in stripes on a surface of the mover facing the stator so as to have electrodes that do not completely overlap each other with the stator electrode; 1. An electrostatic motor comprising: a frictional force damping means provided between a dielectric thin film and a dielectric thin film. (3) The electrostatic motor according to claim 1, wherein the separation holding means is made of an LB film (Langmuir-Blodgett film) having low friction properties.