JPH0340777A - Liquid electrode type electrostatic motor - Google Patents

Abstract

PURPOSE:To reduce a frictional resistance of a slide face by providing a liquid electrode having large surface tension, stator and rotor provided with a plurality of independent metal electrodes moistened with the liquid electrode in an insulating surface layer not moistened with the liquid electrode, and polyphase pulse voltage applying means. CONSTITUTION:A plurality of independent metal electrodes 6 are formed at a plurality of positions on the surface of a stator 5 not moistened with liquid electrode 1, the electrode 1 having large surface tension is disposed in close contact therewith, and the surface of another rotor 2 is covered with a surface layer 5 not moistened with the electrode 1. When the electrode face of the stator 5 is brought into contact with the electrode 1 through the layer 4 of the rotor 2, the lump of the electrode 1 having large surface tension acts as lubricant with the ball of a roll bearing mechanism, and the surface of the electrode 1 acts as a stator electrode.

Description

[Detailed Description of the Invention] [Summary] Regarding the structure of an electrostatic motor, the purpose of the present invention is to provide an electrostatic motor that is used in extremely small mechanical devices and whose sliding surface has extremely low frictional resistance. A stator is provided with a plurality of independent electrode metal parts that are well wetted by the liquid electrodes in an insulating surface layer that does not get wet by large liquid electrodes, and a stator that is formed by covering the plurality of independent electrode metal parts and the electrode metal parts that are well wetted by the liquid electrodes. A rotor provided with an insulating surface layer that does not get wet with liquid electrodes, and a rotor that is tightly fixed to a plurality of independent electrode metal parts of the stator and is slidably (sandwiched between) the insulating surface layer of the rotor. The liquid electrode type electrostatic motor is configured to at least connect the liquid electrode and means for applying a multiphase pulse voltage to one or both of the plurality of independent electrode metal parts of each of the rotor and the stator. do.

[Industrial application field]

The present invention relates to improvements in extremely compact electrostatic motors.

In recent years, with the advancement and development of mechatronics technology, the applications of various robots and control devices have become more popular.

In particular, important fields that require ultra-miniaturization, such as biological applications and space equipment, are expanding recently, and microelectrostatics, which have low power consumption, relatively large driving force, and can be miniaturized, are expanding. Motors are becoming increasingly popular.

However, there are still many points to be improved in these ultra-small electrostatic motors, and in particular, there is a strong demand for the development of means for reducing frictional resistance in the sliding portion.

[Conventional technology]

An ultra-compact micro-electrostatic motor, such as a micro-electrostatic linear motor, has been proposed in which the stator is formed on a silicon substrate and the rotor is formed from a thin film of polysilicon, making the entire structure extremely compact. (Sensors and Actuators,
vol, 14. (See p. 269.1988).

FIG. 7 is a diagram showing an example of a conventional micro electrostatic linear motor, in which 100 is a single crystal silicon substrate, 103 is a lower stator electrode, 104 is an upper stator electrode, 102 is a polysilicon thin film rotor, and 105 is a rotor. Upper electrode, 10
1 is a rotor pedestal.

The feature of this example is that each of the above-mentioned components is laminated on a single crystal silicon substrate 100 by a so-called IC process, with an insulating film or a selectively etched intermediate layer interposed therebetween as necessary, and then a suitable method is used.

For example, only the polysilicon thin film rotor 102 is separated from the single crystal silicon substrate 100 serving as the stator by selective etching, and is configured to be movable. That is, miniaturization is being achieved by applying IC process technology.

In the sliding portion between the rotor and the stator, narrow rotor holders are provided with pedestals 101 at two locations in order to reduce frictional resistance.

The driving method is based on the normal method for electrostatic linear motors described below.

Figure 6 is a diagram explaining the basic configuration of an electrostatic linear motor.
Only the minimum necessary components are shown to understand the driving principle.

In the figure, 50 is a lower stator, 51 is an upper stator, and 60 is a lower stator.
a, 60b, 60c are lower stator electrodes, 61
a, 61b, 61c are upper stay electrodes, 20 are rotors, 30a, 30b are lower rotor electrodes, 31a,
31b is an upper rotor electrode, and 40.41 is a dielectric film.

Now, for example, when a multiphase pulse voltage is applied to the stator electrodes 60 and 61 with the rotor electrode at ground potential, charges of opposite sign are induced in the rotor electrodes adjacent to it due to electrostatic induction, and as a result, for example, the rotor electrodes 30a,
The portion 31a is drawn under the stator electrodes 6°a, 61a. That is, the rotor 20 moves in the direction of the right arrow.

Thereafter, the same process is repeated and the rotors 20 are electrostatically driven one after another. On the other hand, the moving direction of the rotor 20 is controlled to be reversed by reversing the phase of the pulse voltage.

(Secret B to be solved by the invention) In a conventional bearing configuration, for example, a flat bearing, the frictional resistance when the two solid surfaces of the fixed part and the moving part slide is alleviated and reduced through lubricating oil. In a general way,
It has been put into practical use in a wide variety of applications, from large to small mechanical devices. It is well known that lubricating oil also acts as a coolant that removes the heat generated on the slide surface.

On the other hand, for extremely small mechanical devices that are being developed recently, such as the micro electrostatic linear motors described above, which are extremely small in size on the order of 1 mm, this kind of friction reduction is necessary. It is practically impossible to apply the mechanism.

Therefore, at present, such microscopic mechanical devices and mechanical elements do not have special bearing mechanisms, as seen in the example of the micro electrostatic linear motor mentioned above, and their sliding surfaces are configured to be at most small. The current level of friction is limited to suppressing friction as much as possible.

However, in the future, even microelectrostatic motors will increasingly be required to have a relatively large load capacity or a sliding surface that can move at high speed. There is a problem in that a stable and highly reliable rotation or sliding mechanism cannot be obtained by such means, and a solution to this problem is needed.

[Means to solve the problem]

The above problem is solved by forming a plurality of independent liquid electrodes 1 in the insulating surface layer 7 which is not wetted by the liquid electrode 1 having a high surface tension.
a stator 5 provided with an electrode metal part 6 that is well wetted by the liquid; a rotor 2 provided with a plurality of independent electrode metal parts 3 and an insulating surface layer 4 that does not get wet by the liquid electrode 1 formed over the plurality of independent electrode metal parts 3; The liquid electrode 1 is closely fixed to a plurality of independent electrode metal parts 6 of the stator 5 and slidably sandwiched between the insulating surface layer 4 of the rotor 2, and the rotor 2. This problem can be solved by a liquid electrode type electrostatic motor having at least means for applying a multiphase pulse voltage to one or both of the plurality of independent electrode metal parts 3 and 6 of the stator 5.

[Effect]

FIG. 1 is a cross-sectional view explaining the present invention in detail, and FIG.
shows the state at low load, and (b) shows the state at high load.

In the figure, l is a liquid electrode, such as mercury or gallium, which has a high surface tension. 2 is a rotor, for example, a base plate made of glass or Si; 3 is an electrode metal part embedded in the rotor 2; for example, ^U, ^l, etc. are used. 4 is an insulating surface layer that does not get wet with the liquid electrode l, for example, Sing or polyimide resin film,
Reference numeral 5 denotes a stator, which is a substrate made of glass or Si, for example. Reference numeral 6 denotes independent electrode metal parts provided at a plurality of locations on the surface of the stator 5, which are well wetted by the liquid electrode 1.

For example, a metal pattern made of Ni or Cr is used. Reference numeral 7 denotes an insulating surface layer which exposes the electrode metal part 6 and covers other parts and which does not get wet with the liquid electrode 1, and is, for example, a SiO2 or polyimide resin film.

As shown in the same figure (a), the liquid electrode 1 with high surface tension
．． For example, mercury has high wettability in the electrode metal part 6. For example, it is well wetted and tightly fixed to a circular Ni portion, and is raised in a hemispherical shape on the surface of the stator 5. on the other hand,
The surface of the rotor 2 is covered with a non-wetting surface, for example, a polyimide resin film, so even if the side substrates are brought into contact with a hemispherical mercury sandwiched between them, the surface tension of the mercury will cause the surface of the side substrates to directly There will be no contact.

However, if a load is applied to the rotor 2 or the load between the peripheral substrates increases due to the electrostatic attraction between the two electrodes during driving, the hemispherical mercury as shown in the figure (b) is crushed and the distance between the surfaces of the side substrates decreases, but as the diameter of each mercury particle, that is, the circumference increases, the internal pressure due to surface tension increases and the gap balances out the external load and becomes stable. do.

When a sliding force acts between the peripheral substrates in this state, the surface of the rotor 2 is covered with the non-wetting surface layer 4, so it can slide extremely smoothly without mercury adhering.

By selecting the size of the highly wettable electrode metal parts 6 and their mutual spacing, and by selecting the type of liquid with high surface tension, frictional resistance, load-bearing characteristics, and high-speed operation characteristics can be improved. can be controlled.

That is, according to the present invention, independent electrode metal parts 6 with good wettability are formed at a plurality of predetermined locations on the surface of the stator 5 that are not wetted by the liquid electrode 1, and the liquid electrode 1 with high surface tension is placed thereon. For example, the surface of the other rotor 2 is covered with a surface layer 4 that does not wet the liquid electrode 1, and the electrode surface of the stator 5 and the surface layer 4 of the rotor 2 are covered with the liquid electrode 1. When brought into contact with each other by sandwiching them, the mass of the liquid electrode 1 having a high surface tension acts just like the balls and lubricating oil of a conventional rolling bearing mechanism, and the surface of the liquid electrode 1 acts as a stator electrode. , the distance between the rotor electrode and the stator electrode becomes extremely small, only the thickness of the insulating surface layer 4, the electric field strength of the picture electrode increases, and the electrostatic attraction force correspondingly increases significantly.

Therefore, an electrostatic motor with extremely low frictional resistance on the sliding surface and with high driving force can be obtained.

[Embodiment] Fig. 2 is a perspective view of the first embodiment of the present invention, which is an example of an extremely small micro electrostatic linear motor, and the housing and some other components are omitted for clarity. It is.

In the figure, la and lb are liquid electrodes, for example, semicylindrical mercury particles that are wetted and fixed in close contact with the electrode metal parts 6 made of Ni that are arranged in two parallel rows on the stator 5 made of a Si substrate. . Reference numeral 2 designates a rectangular rotor, for example, made of the same <Si substrate, on which a separate electrode metal part 3 made of a vapor-deposited film is formed, and then the entire surface thereof is covered with a polyimide resin film.

Note that the inter-electrode pitch of the electrode metal portions 3 of the rotor 2 is 1.5 times the inter-electrode pitch of the electrode metal portions 6 of the stator 5.

Further, R, S, and T shown in the figure are three-phase pulse voltage application terminals, and are connected to the electrode metal portion 6 of the stator 5. therefore,
Each is connected to the liquid electrode l via a crossover.

The figure shows the wiring on the side and surface of the stator board, but it may also be wired inside the board, or
Of course, all wiring may be done on the surface, or another wiring board may be used.

Comparing the electrode arrangement of this example with that of FIG. 6 above,
The stator electrodes 60 and 61 shown in FIG. 6 are spread out on one plane at regular intervals, the rotor is arranged at the upper center between the stator electrode rows, and the rotor electrode row on one side is omitted. Therefore, the driving mechanism of the device of this embodiment is the same as that explained in FIG. 2 can be driven.

In this embodiment, the liquid metal 1 was tightly fixed on the stator 5, but on the contrary, the liquid metal 1 was fixed on the rotor 2.
It goes without saying that a micro electrostatic linear motor may be constructed by closely fixing the stator 5 and forming an insulating surface layer 4 on the stator 5 that does not get wet with the liquid metal 1.

Now, the manufacturing process for realizing the device of the present invention as described above will be specifically explained in order of process.

The first figure is a sectional view showing an example of the manufacturing process of the device according to the first embodiment of the present invention.

Process (1): Thickness 1001! on a silicon substrate of
An Al film with a thickness of 0.5 μm is formed by vacuum evaporation, and the electrode metal portion 3 is patterned into a predetermined shape by photolithography.

Step (2): On the Affi film of the treated substrate, an insulating surface layer 4 that does not get wet with the liquid metal 1 is formed to a thickness of 0.5
The rotor 2 is prepared by forming a .mu.m thick polyimide resin layer by a spin cord method.

Step (3): Form a Ni film with a thickness of 0.5 μm, which will become the electrode metal part 6, on the same silicon substrate with a thickness of 100 μm using a vacuum evaporation method, and then form the electrode metal into a predetermined shape using a photolithography method. The portion 6 is patterned.

Step (4): A polyimide resin layer with a thickness of 0.5 μm is formed on the Ni film of the treated substrate by a spin cord method.

Step (5)): Form a hole in the polyimide resin layer of the treated substrate by photoetching or ion etching to tightly fix the liquid electrode l having a high surface tension, exposing the Ni film on the bottom surface, and further, The stator 5 is prepared by forming a driving wiring pattern and external lead lead terminals (not shown).

Step (6)): Electroplating is performed on the Ni film exposed surface of the treated substrate, for example, in an Hg(N(h)z aqueous solution, using the Ni film as a cathode, and a liquid consisting of hemispherical mercury grains is applied. Electrode 1 is formed.

Step (7)): The rotor 2 processed above and the stator 5 are brought into sliding contact with each other across the liquid electrode 1 made of the electrolytically deposited mercury particles (not shown here). By constructing the whole together with the housing, for example, a micro electrostatic linear motor of the present invention can be formed.

It should be noted that the manufacturing method of the above embodiment is just an example, and it goes without saying that other materials and manufacturing processes can be used in combination as appropriate to construct the electrostatic motor of the present invention. The liquid metal 1 was fixed in close contact with the rotor 2, but the liquid metal 1 was placed on the rotor 2.
The manufacturing process may be configured such that the liquid metal 1 is tightly fixed and an insulating surface layer 4 that does not get wet with the liquid metal 1 is formed on the stator 5.

The diagram shows a second embodiment of the present invention, in which a rotary electrostatic motor is used in contrast to the micro electrostatic linear motor of the previous embodiment.

Both electrodes are arranged radially around the rotation axis, and the liquid electrode 1 is sandwiched between them.

In this example, an electrode metal part 6 that is well wetted by the liquid electrode 1 is provided on the rotor 2, and the liquid metal 1 is closely fixed there, and an insulating surface layer 4 that does not get wet by the liquid metal 1 is provided on the surface of the stator 5. The only difference is in what is provided. Of course, the configuration may be reversed, but this example shows the case of a horizontal rotary electrostatic motor that is easy to maintain, easy to manufacture, and other aspects.

In this case as well, as in the case of the second embodiment, an electrode metal part 6 that is well wetted by the liquid electrode 1 is provided on the a-tor 2, and the liquid metal 1 is closely fixed thereto, and the surface of the stator 5 is An insulating surface layer 4 that does not get wet with the liquid metal 1 is provided on the surface. Of course, it goes without saying that the configuration may be reversed.

It should be noted that the configurations of the above embodiments are all specific examples, and it goes without saying that the present invention is not limited to these examples and can be widely applied to other shapes and designs.

〔Effect of the invention〕

As explained above, according to the present invention, the liquid electric 8i! 1
Independent electrode metal portions 6 with good wettability are formed at predetermined multiple locations on the surface of the stator 5 that are not wetted by water, and liquid electrodes 1 with high surface tension are closely arranged therein in a hemispherical shape, and The surface of one rotor 2 is coated with a surface layer 4 that does not wet the liquid electrode 1, and when the electrode surface of the stator 5 and the surface layer 4 of the rotor 2 are brought into contact with the liquid electrode 1 in between, the surface tension The large mass of liquid electrode 1 acts just like the balls and lubricating oil of a conventional rolling bearing mechanism, and the surface of liquid electrode 1 acts as a stator electrode, so the distance between the rotor electrode and stator electrode can be reduced. becomes extremely small, only the thickness of the insulating surface layer 4, the electric field strength at both electrodes increases, and the electrostatic attraction increases accordingly.

Therefore, the frictional resistance on the sliding surface is extremely small,
In addition, it greatly contributes to improving the performance and quality of electrostatic motors, such as by increasing the driving force, and to miniaturization.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the present invention in detail, Fig. 2 is a perspective view of the first embodiment of the invention, and Fig. 3 is a cross-sectional view showing an example of the manufacturing process of the device of the first embodiment of the invention. , FIG. 4 is a diagram showing a second embodiment of the present invention, FIG. 5 is a diagram showing a third embodiment of the present invention, FIG. 6 is a diagram explaining the basic configuration of an electrostatic linear motor, and FIG. 1 is a diagram showing an example of a conventional micro electrostatic linear motor. In the figure, Hla, 1b) is a liquid electrode, 2 is a rotor, 3.6 is an electrode metal part, 5 is a stator, and 4.7 is an insulating surface layer that does not get wet with the liquid electrode. A4 During the 2nd of September, the reason is fte' Afromom Thursday, Friday, January 11th, 1st/) The actual person is coming. Missed L's minute] δ year old, Senren White's face picture Dane's J, 4ea month's second fruit Yoshimi Ita j poor Nesu C Takumi I 4
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Claims (1)

[Scope of Claims] A plurality of independent electrode metal parts (6) that are easily wetted by the liquid electrode (1) are provided in an insulating surface layer (7) that cannot be wetted by the liquid electrode (1) having a large surface tension. a stator (5), a plurality of independent electrode metal parts (3), and an insulating surface layer (which does not get wet with the liquid electrode (1) formed covering the stator (5)).
4); and a plurality of independent electrode metal parts (6) of the stator (5).
the liquid electrode (1) tightly fixed to the rotor (2) and slidably sandwiched between the insulating surface layer (4) of the rotor (2); and the rotor (2) and the stator (5). A liquid electrode type electrostatic motor comprising at least means for applying a multiphase pulse voltage to one or both of the plurality of independent electrode metal parts (3, 6).