JP2010090787A - Fluid actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid actuator achieving unprecedented large drive force by using force other than Coulomb force. <P>SOLUTION: This fluid actuator 10 charges charged fluid 11 and moves the same by an electric field between electrodes, and includes a first electrode 21 and a second electrode 22 as the electrodes opposing with the charged fluid 11 put therebetween. The first electrode 21 and the second electrode 22 apply to the charged fluid 11 a force proportional to square of the electric field applied on the charged fluid 11 between the first electrode 21 and the second electrode 22. The second electrode 22 comprises a plurality of electrodes 221, 222 applying different voltage on the first electrode 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluid actuator that charges and moves a charged fluid by an electric field between electrodes.

  A liquid that is charged when it touches an electrode having a potential or is rubbed against another object is called an electric field conjugate liquid (ECF) by some academic societies (Patent Document 1, Patent Document 2, etc.). In the present application, this liquid is defined as a charged fluid. Many papers on pumps or motors using this charged fluid have been published.

  Patent Document 3 discloses a fluid actuator that imparts a driving force by a Coulomb force generated by an electric field between electrodes immersed in a charged fluid to the charged fluid. This type of fluid actuator generates a driving force by an electric field after the charged fluid is charged, and loses the driving force after the charged fluid reaches the electrode and discharges. For this reason, a jet stream of charged fluid is formed. This driving force varies depending on the characteristics of the charged fluid, the shape and type of the electrodes, the arrangement of the electrodes, the voltage between the electrodes, and the like. This jet flow mechanism is called EHD (Electro-Hydraulic Dynamics), and it is important to efficiently generate the driving force and use the driving force.

Utility Model Registration No. 3041928 JP-A-11-215869 JP 2007-196316 A

  By the way, when analyzing the fluid actuator disclosed in the above-mentioned Patent Document 3, the distance between the pair of electrodes to which the plus potential and the ground potential are applied is narrowed, and the distance between the pair of electrodes to be paired is set wide. Yes.

  Therefore, in a conventional fluid actuator, an electric field is generated between the two electrodes by applying a plus potential and a ground potential to the two electrodes having a small interval, and the Coulomb force generated by the electric field is used as a driving force. Applied to charged liquid. The charged liquid flows as a jet flow under the driving force by the Coulomb force.

  However, the technique using only the Coulomb force has a limit in obtaining a sufficient driving force. This has been a major issue in putting this type of fluid actuator into practical use.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fluid actuator that realizes a large driving force that has never existed before by using a force other than the Coulomb force.

  In order to achieve the above object, a fluid actuator according to the present invention is a fluid actuator in which a charged fluid is charged and moved by an electric field between the electrodes, and the first electrode and the second electrode facing each other with the charged fluid interposed therebetween The first electrode and the second electrode have a force proportional to the square of the electric field applied to the charged fluid between the first electrode and the second electrode. It is characterized by giving to.

  According to the present invention, a driving force larger than the Coulomb force proportional to the electric field is obtained by applying to the charged fluid a force proportional to the square of the electric field applied to the charged fluid between the first electrode and the second electrode. Is obtained. Therefore, by using a force other than the Coulomb force, a fluid actuator that realizes an unprecedented large driving force can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (1) 2-ethylhexyl benzyl phthalate (trade name; Plicizer B) as a charged fluid with the property of being charged positively (+) or negatively (-) when it touches an electrode with potential or rubs against another object -8), (2) 9,10-epoxy bull stearate (trade name; Sansosizer E-4030), (3) terahydrphthalic acid dioctyl ester (trade name; Sansosizer DOTP), (4) propylene glycol methyl ether acetate (PMA), (5) methyl acetyl lysylate (MAR-N), (6) 2-ethylhexyl palmitate (trade name; Exepal EH-P), (7) butyl stearate (trade name; Exepal BS), decane Dibutyl diacid etc. exist.

  Further, the charged fluid is not limited to the one that itself is charged, and the solute contained in the solvent may be charged. The charged fluid may be either positive (+) or negative (−) monopolar charged, bipolar charged or ionized. As a charged liquid that is bipolarly charged, it has the same effect as being positively and negatively charged by touching a potential electrode, and unipolarly charged to either positive or negative depending on the difference between positive and negative magnitudes. As long as it exhibits In addition, as a charged liquid to be ionized, it touches an electrode having a potential and is ionized to be positively and negatively charged, and is unipolarly charged to either positive or negative depending on the difference between positive and negative magnitudes. As long as it exhibits the same effect as the above. Further, the charged liquid is not limited to the liquid itself having a charging characteristic, but the solute contained in the solvent may have a charging characteristic. Further, although only the case where the charged fluid is a liquid has been described, a charged gas may be used. In short, the charged fluid may be any fluid (including liquid and gas) having a property of being charged by touching an electrode having an electric potential or rubbing against another object. In the following description, embodiments of the present invention will be described by taking a charged liquid as a kind of charged fluid as an example.

  FIG. 1 [1] is a cross-sectional view showing a first embodiment of a fluid actuator according to the present invention. Hereinafter, description will be given based on this drawing.

  The fluid actuator 10 of the present embodiment charges and moves the charged fluid 11 by the electric field between the electrodes, and includes a first electrode 21 and a second electrode 22 as the electrodes facing each other with the charged fluid 11 interposed therebetween. ing. The first electrode 21 and the second electrode 22 give the charged fluid 11 a force proportional to the square of the electric field applied to the charged fluid 11 between the first electrode 21 and the second electrode 22. The second electrode 22 includes a plurality of electrodes 221 and 222 to which different voltages are applied to the first electrode 21. The second electrode 22 in this embodiment includes two electrodes 221 and 222. The two electrodes 221 and 222 are disposed along the flow 111 of the charged fluid 11 and are applied with different voltages Vp and Vq. In other words, the first electrode 21 and the second electrode 22 are applied to the charged fluid 11 between the first electrode 21 and the second electrode 22 along the electric field strength (or dielectric) along the flow 111 of the charged fluid 11. Regions (or gradients) with different rates are formed.

  The electrode 21 is formed on the insulating substrate 12, and the electrodes 221 and 222 are formed on the insulating substrate 13. The insulating substrates 12 and 13 have, for example, a flat plate shape, and at least the surfaces on which the electrodes 21, 221, and 222 are formed should have insulating properties. The insulating substrates 12 and 13 are parallel to each other, and the charged fluid 11 is filled in the gap formed by the insulating substrates 12 and 13. The electrodes 21, 221, 222 are made of, for example, a conductive metal film.

  The charged fluid 11 is charged with a positive or negative voltage. A voltage Vg is applied to the electrode 21, a voltage Vp is applied to the electrode 221, and a voltage Vq is applied to the electrode 222. Vg = 0 and Vg <Vp <Vq. Therefore, the charged fluid 11 on the electrode 221 becomes a weak electric field, and the charged fluid 11 on the electrode 222 becomes a strong electric field. Therefore, the degree of charging with respect to the charged fluid 11 is low (not easily charged) at the position on the electrode 221 and high (easily charged) at the position on the electrode 222. That is, the degree of charging with respect to the charged fluid 11 varies depending on the position on the second electrode 22.

  Next, the operation of the fluid actuator 10 will be described. When a high voltage is applied to the charged fluid 11, the above-described pumping force called EHD is generated by the interaction between the electric field and the flow generated in the charged fluid 11. Volume force (hereinafter referred to as “driving force” in this specification) f generated by an electric field is expressed by the following equation.

f = ρ _e E− (1/2) E ² ∇ε + (1/2) ∇ [E ² (∂ε / ∂ρ) _T ρ] ... <1>
Here, ρ _e represents the charge density, E represents the electric field, ε represents the dielectric constant, and ρ represents the density of the charged fluid. f, E, and ∇ are vector quantities, and others are scalar quantities.

  In the right side of the formula <1>, the first term indicates the Coulomb force, and the second and third terms indicate the force due to the polarized charged molecule. The third term indicates a force resulting from electrostriction that occurs when the charged fluid 11 is compressed, and can be ignored in the case of a general charged fluid, that is, an incompressible fluid. Conventional fluid actuators (Patent Document 3 and the like) use the Coulomb force indicated by the first term on the right side of Equation <1>.

  In the present embodiment, the first electrode 21 and the second electrode 22 that are opposed to each other with the charged fluid 11 interposed therebetween are provided, and the electric field (or the degree of charging) with respect to the charged fluid 11 depends on the position on the second electrode 22. Are different. At this time, it has been clarified that the driving force f generated by the electric field is greatly affected by the force of the second term on the right side of the formula <1> (see the example described later). This is because the electric field (or the degree of charging) of the charged fluid 11 varies depending on the position on the second electrode 22, so that the charged fluid 11 between the first electrode 21 and the second electrode 22 has a dielectric. This is thought to be due to the non-uniformity of the rate. In general, when the electric field applied to the charged fluid 11 is increased, the dielectric constant of the charged fluid 11 is substantially constant until a certain point, but starts to decrease as the polarization is saturated. The charged fluid 11 may be any fluid as long as the dielectric constant changes according to the electric field. For example, the charged fluid 11 may increase in dielectric constant as the electric field becomes stronger. Whereas the Coulomb force of the first term on the right side of Equation <1> is proportional to the electric field, the force of the second term on the right side of Equation <1> is proportional to the square of the electric field, so that a larger driving force can be obtained.

  If the electric field intensity on the surface of the second electrode 22 with respect to the charged fluid 11 is made different depending on the position of the surface of the second electrode 22, in other words, electrons are transferred according to the position of the surface of the second electrode 22. As a result, the degree of charging differs depending on the position on the second electrode 22.

  In the present embodiment, the voltage Vp is applied to the electrode 221 and the voltage Vq (> Vp) is applied to the electrode 222, so that the + charged molecule is directed toward the electrode 21 by a change in electric field strength in two steps. Accelerate diagonally up. Attracted from point A to point B-Charged molecules are accelerated at point C from point B to point D, and almost all charged molecules from point D to point B are eliminated (from the electric field from point D to point B). However, the electric field from point D to electrode 21 is stronger.) Since the electric field at the point A is weaker than the electric field at the point E, the degree of charge of the molecules is small, and acceleration of the charged fluid 11 in the opposite direction is suppressed at the points A and C. In the entire region including each point of ABCDE, a heterocharge layer (a layer having a charge opposite to the polarity of the electrode) is formed, and a force that prevents acceleration of charged molecules directly from the electrode 22 to the electrode 21 acts.

  In other words, the liquid molecules of the charged fluid 11 are not always charged when they touch the high-potential electrodes 221 and 222, but are charged when they touch the electrodes 221 and 222 whose electric field is higher than the electric field determined by the type of the charged fluid 11. . Therefore, by adjusting the values of the voltages Vp and Vq, charged molecules that are already charged are collected by attracting and dielectric action in the vicinity of the points A and B of the electrode 221, and charged and coulombed in the vicinity of the points D and E where the electric field is strong. By accelerating with force, it is possible to generate acceleration force due to a large change in dielectric constant.

  The driving force of the fluid actuator 10 is the sum of the force generated by the product of the change in dielectric constant and the square of the electric field (Formula <1>, the second term on the right side) and the Coulomb force (Formula <1>, the first term on the right side). It is. The Coulomb force works most strongly at the edge E point of the electrode 222 where the electric field is concentrated and charging is likely to occur. The voltage Vq to be applied to the electrode 222 is appropriately selected so that the electric field becomes strong at the edge E point. Then, since the electric field is weaker at the surface F point of the electrode 222 than at the edge E point, the dielectric constant of the charged fluid 11 is increased. At the edge E point, the electric field is increased, so that the dielectric constant of the charged fluid 11 is decreased. For this reason, the force generated at the edge E point is proportional to the product of the rightward downward gradient of the dielectric constant of the charged fluid 11 and the square of the electric field, and thus has a large rightward value. As the distance from the edge E further increases, the dielectric constant of the charged fluid 11 has an upward slope to the right, but since the electric field applied to the charged fluid 11 decreases, the force proportional to the product of the square of the electric field is directed to the left but rapidly. Becomes smaller. Note that, at the edge D point, the electric field is relaxed by the voltage Vp applied to the electrode 221, so that the phenomenon like the edge E point does not occur.

  Furthermore, the fluid actuator 10 includes one first electrode 21 and a plurality of second electrodes 22, and the plurality of second electrodes 22 are arranged one by one along the flow 111 of the charged fluid 11, One first electrode 21 may be provided so as to face all of the plurality of second electrodes 22. In this case, a plurality of second electrodes 22 are opposed to one first electrode 21, and one first electrode 21 and a plurality of second electrodes 22 are along the flow 111 of the charged fluid 11. Arranged. Therefore, the driving force generated between the first electrode 21 and the entire second electrode 22 is a multiple of that compared to the case where there is only one second electrode 22. In other words, the EHD pump may be configured by appropriately bringing two striped electrodes 221 and 222 close to each other and arranging a plurality of pairs at an appropriate interval. By arranging a large number of these two sets of striped electrodes 221, 222, a pumping effect can be produced efficiently at a low voltage.

  As described above, according to the present embodiment, the first electrode 21 and the second electrode 22 facing each other with the charged fluid 11 interposed therebetween are provided, and the electric field (or the degree of charging) with respect to the charged fluid 11 is set to the second. Since the charged fluid 11 between the first electrode 21 and the second electrode 22 has a nonuniformity in dielectric constant due to the difference depending on the position on the electrode 22, a large proportion proportional to the square of the electric field. Driving force can be obtained. Therefore, by using a force other than the Coulomb force in addition to or instead of the Coulomb force, it is possible to provide the fluid actuator 10 that realizes a large driving force that has not been obtained conventionally. Further, the flow path of the charged fluid 11 is constituted by the parallel flat plate-like insulating substrates 12 and 13, but may be constituted by any shape of insulator such as a cylinder such as a cylinder or a disk. Good.

  FIG. 1 [2] is sectional drawing which shows 2nd embodiment of the fluid actuator based on this invention. Hereinafter, description will be given based on this drawing. In FIG. 1 [2], the same parts as those in FIG. 1 [1] are denoted by the same reference numerals as those in FIG. 1 [1].

  The second electrode 32 in the fluid actuator 30 of the present embodiment has a region 321 covered with the insulating film 34 and a region 322 where the second electrode 32 is exposed. Since it is difficult for charges to pass through the insulating film 34, the degree of charging with respect to the charged fluid 11 is low in the region 321 covered with the insulating film 34 and high in the exposed region 322. That is, the degree of charging with respect to the charged fluid 11 varies depending on the position on the second electrode 32.

  In addition, a capacitor made of the insulating film 34 and a capacitor made of the charged fluid 11 are connected in series between the region 321 covered with the insulating film 34 of the electrode 32 and the electrode 21. Therefore, a voltage having a value obtained by dividing the voltage Vp is applied to the charged fluid 11 on the region 321. On the other hand, the voltage Vp is applied as it is to the charged fluid 11 on the exposed region 322. Therefore, the electric field strength with respect to the charged fluid 11 varies depending on the position on the second electrode 32.

  Further, since repulsive jets of charged molecules occur at the points D and E in the region 322, the charged fluid 11 flows not only directly above the electrode 21 but also to the right. Finally, the charged molecules are attracted to the electrode 21 and the charge is neutralized. At points A and B in the region 321, the charged fluid 11 is not charged, so no jet flow occurs. Rather, at points A, B, and C, molecules of the charged fluid 11 are attracted by the dielectric force and Coulomb force and supplied to the point D, thereby preventing the back flow of the charged fluid 11. In the entire region including each point of ABCDE, a heterocharge layer (a layer having a charge opposite to the polarity of the electrode) is formed, and a force that prevents acceleration of charged molecules directly from the electrode 32 to the electrode 21 acts. However, at point E, the electric field is strong because of the edge, and the charged molecules are accelerated obliquely upward.

  Furthermore, the fluid actuator 30 includes one first electrode 21 and a plurality of second electrodes 32, and the plurality of second electrodes 32 are arranged one by one along the flow 111 of the charged fluid 11, One first electrode 21 may be provided so as to face all of the plurality of second electrodes 32. At this time, a large number of electrodes 32 are arranged in parallel at an appropriate interval, the flow path width is made as small as possible, and the flow path width and applied voltage are set so as to obtain a larger flow rate at a low voltage.

  Other configurations, operations, and effects are the same as those in the first embodiment. According to the present embodiment, the first electrode 21 and the second electrode 32 that are opposed to each other with the charged fluid 11 interposed therebetween are provided, and the electric field strength (or the degree of charging) with respect to the charged fluid 11 is set on the second electrode 32. Since the dielectric constant is nonuniform in the charged fluid 11 between the first electrode 21 and the second electrode 32 due to the difference depending on the position, a large driving force proportional to the square of the electric field is obtained. It is done. Therefore, by using a force other than the Coulomb force in addition to the Coulomb force or using a force other than the Coulomb force, it is possible to provide the fluid actuator 30 that realizes an unprecedented large driving force. In addition, the fluid actuator 30 of this embodiment may have only one electrode constituting the second electrode 32 as compared with the fluid actuator of the first embodiment, and therefore the voltage applied to the second electrode 32 is also one. Therefore, the configuration can be simplified.

  FIG. 2 [1] is a cross-sectional view showing a third embodiment of the fluid actuator according to the present invention. Hereinafter, description will be given based on this drawing. In FIG. 2 [1], the same parts as those in FIG. 1 [1] are denoted by the same reference numerals as those in FIG. 1 [1].

  The second electrode 42 in the fluid actuator 40 of the present embodiment includes one or more electrodes 223 to which no voltage is applied between the two electrodes 221 and 222. All of the electrodes 221 and 223 and a part of the electrode 222 are covered with the insulating film 44, and the remaining part of the electrode 222 is exposed. In FIG. 2 [1], nine electrodes 223 are shown.

  Since no voltage is applied to each electrode 223, a potential between the voltage Vp of the electrode 221 and the voltage Vq of the electrode 222 can be taken. That is, when the voltage of each electrode 223 is Vr, Vp <Vr <Vq is established. The voltage Vr of each electrode 223 is closer to Vp as it is closer to the electrode 221, and closer to Vq as it is closer to the electrode 222. However, since the entire electrode 223 has the same potential, the potential gradient between the two electrodes 221 and 222 is substantially stepped. As described above, when the electrode 223 is provided between the two electrodes 221, 222, a specific potential gradient is obtained.

  In other words, in the present embodiment, the electrode 223 on a slender and thin stripe is disposed between the electrode 221 and the electrode 222. Since this shape can be produced by a technique such as lithography, for example, 10 to 20 fine wires each having a width of 1 μm are inserted in a comb shape at a distance of 1 μm. When 0 <Vp <Vq, this interdigital and striped electrode 223 is equivalent to an electrode in which capacitors are arranged in series between the electrode 221 and the electrode 222. As a result, a potential distribution is created in a small step shape between the electrode 221 and the electrode 222. As illustrated, the electrode 221 other than the electrode 222 and the electrode 223 may be covered with an insulating film 44. Even though the insulating film 44 is an insulator, it may not be completely nonconductive, so that a stepwise potential distribution is smooth.

  The fluid actuator 40 includes one first electrode 21 and a plurality of second electrodes 42, and the plurality of second electrodes 42 are arranged one by one along the flow 111 of the charged fluid 11, One first electrode 21 may be provided so as to face all of the plurality of second electrodes 42.

Other configurations, operations, and effects are the same as those in the first embodiment. According to the present embodiment, the first electrode 21 and the second electrode 42 that are opposed to each other with the charged fluid 11 interposed therebetween are provided, and the electric field (or the degree of charging) with respect to the charged fluid 11 is positioned on the second electrode 42. Since the dielectric constant nonuniformity occurs in the charged fluid 11 between the first electrode 21 and the second electrode 42, a large driving force proportional to the square of the electric field can be obtained. . Therefore, by using a force other than the Coulomb force in addition to or instead of the Coulomb force, it is possible to provide the fluid actuator 40 that realizes an unprecedented large driving force.
is there.

  FIG. 2 [2] is a sectional view showing a fourth embodiment of the fluid actuator according to the present invention. Hereinafter, description will be given based on this drawing. 2 [2], the same parts as those in FIG. 1 [1] are denoted by the same reference numerals as those in FIG. 1 [1].

  The second electrode 52 in the fluid actuator 50 of the present embodiment has a resistance film 55 provided so as to connect the two electrodes 221 and 222. The electrode 221 and the resistance film 55 are entirely covered with the insulating film 54, and the electrode 222 is partially covered with the insulating film 54.

  Since the resistance film 55 is in contact with the two electrodes 221 and 222, it can take a voltage between the voltage Vp of the electrode 221 and the voltage Vq of the electrode 222. That is, when the voltage of the resistance film 55 is Vr, Vp <Vr <Vq is established. The voltage Vr of each part of the resistance film 55 is closer to Vp as it is closer to the electrode 221, and closer to Vq as it is closer to the electrode 222. Therefore, the gradient of the voltage Vr between the two electrodes 221 and 222 is substantially linear. As described above, when the resistance film 55 is provided between the two electrodes 221 and 222, a specific potential distribution is obtained.

  In other words, in this embodiment, the potential between the electrodes 221 and 222 is given a gradient by making the resistance film 55 having a high resistivity between the electrode 221 and the electrode 222. By obtaining a continuous potential gradient, the same effect as in the third embodiment can be obtained.

  The fluid actuator 50 includes one first electrode 21 and a plurality of second electrodes 52, and the plurality of second electrodes 52 are arranged one by one along the flow 111 of the charged fluid 11, One first electrode 21 may be provided so as to face all of the plurality of second electrodes 52.

  Other configurations, operations, and effects are the same as those in the first embodiment. According to the present embodiment, the first electrode 21 and the second electrode 52 that are opposed to each other with the charged fluid 11 interposed therebetween are provided, and the electric field (or the degree of charging) with respect to the charged fluid 11 is positioned on the second electrode 52. Since the dielectric constant is nonuniform in the charged fluid 11 between the first electrode 21 and the second electrode 52, a large driving force proportional to the square of the electric field can be obtained. . Therefore, by using a force other than the Coulomb force in addition to or instead of the Coulomb force, it is possible to provide the fluid actuator 50 that realizes an unprecedented large driving force.

  FIG. 3 [1] is a cross-sectional view showing a fifth embodiment of the fluid actuator according to the present invention. Hereinafter, description will be given based on this drawing. In FIG. 3 [1], the same parts as those in FIG. 1 [1] are denoted by the same reference numerals as those in FIG. 1 [1].

  The fluid actuator 60 of the present embodiment includes one first electrode 21 and a plurality of second electrodes 621,..., And the plurality of second electrodes 621,. One first electrode 21 is provided so as to face each of the plurality of second electrodes 621... In FIG. 3 [1], six second electrodes 621 to 626 are shown.

  Since the second electrodes 621 are non-parallel to the first electrode 21, the second electrodes 621 have a region 62 a far from the first electrode 21 and a region 62 b close to the first electrode 21. Therefore, the charged fluid 11 on the region 62a far from the first electrode 21 has a weak electric field, and the charged fluid 11 on the region 62b close to the first electrode 21 has a strong electric field. Therefore, the degree of charging with respect to the charged fluid 11 is low in the region 62 a far from the first electrode 21 and is high in the region 62 b close to the first electrode 21. That is, the electric field (or degree of charging) with respect to the charged fluid 11 varies depending on the position on the second electrodes 621. Further, since the second electrodes 621,... Are plate-like, the driving force generated on the back surface 62c can also be used.

  In addition, when the striped electrodes 621,... Are tilted as shown in the drawing, the electric field can be tilted, and depending on the voltage, the charging can be set only at the right end of the electrodes 621. That is, the charged fluid 11 flows in the right direction by ejection of charged molecules at the right end of the electrodes 621. In other words, the charged molecules in contact with both surfaces of the electrodes 621,... Form a heterocharge layer and are charged in contact with the electrodes 621,... And jet from the edge of the electrodes 621,.

  Other configurations, operations, and effects are the same as those in the first to fourth embodiments. According to this embodiment, the first electrode 21 and the second electrodes 621,... Facing each other with the charged fluid 11 in between are provided, and the electric field (or the degree of charging) with respect to the charged fluid 11 is set to the second electrode 621. ... That varies depending on the upper position causes a non-uniform dielectric constant in the charged fluid 11 between the first electrode 21 and the second electrode 621..., And is proportional to the square of the electric field. A large driving force can be obtained. Therefore, by using a force other than the Coulomb force in addition to or instead of the Coulomb force, it is possible to provide the fluid actuator 60 that realizes an unprecedented large driving force.

  Further, the insulating substrate 13 and the second electrodes 621 shown in FIG. 3 [1] may be formed like the insulating substrate 13 'and the second electrodes 621' shown in FIG. 3 [2]. . The insulating substrate 13 'has a sawtooth cross section, and second electrodes 621', ... are formed on the same surface of the sawtooth in the same direction. Such a structure can be easily obtained by using microfabrication techniques such as photolithography, sputtering (or vapor deposition), and etching.

  In other words, in the example shown in FIG. 3 [2], in order to obtain the same effect as the inclined electrodes 621,... Shown in FIG. .. Are made uneven, and electrodes 621 ′,. For example, the insulating substrate 13 may be processed into a washing plate shape, and metal electrodes 621 ',... Thereby, the jet of the charged fluid 11 can be generated from the apex of the electrodes 621 ',. Naturally, the opposing flat electrode 21 is disposed.

  FIG. 4 [1] is a plan view showing a sixth embodiment of the fluid actuator according to the present invention. FIG. 4 [2] is a longitudinal sectional view taken along line II in FIG. 4 [1]. Hereinafter, description will be given based on this drawing. 4 that are the same as those in FIG. 1 have the same reference numerals as those in FIG.

  FIG. 4 [1] shows a state in which the insulating substrate 12 and the first electrode 21 are removed. The fluid actuator 70 of this embodiment includes one first electrode 21 and a plurality of second electrodes 72, and the plurality of second electrodes 72 are arranged one by one along the flow 111 of the charged fluid 11. In addition, one first electrode 21 is provided so as to face all of the plurality of second electrodes 72. Although not shown, a voltage is applied to the first electrode 21 and the second electrode 72 so that the first electrode 21 has a voltage Vg and the second electrode 72 has a voltage Vp (> Vg).

  The second electrode 72 is non-parallel to the first electrode 21, the region 721 far from the first electrode 21 is covered with the insulating film 74, and the region 722 near the first electrode 21 is exposed. Yes. The exposed region 722 of the second electrode 72 has a triangular planar shape, and the area decreases as the area is closer to the first electrode 21. The insulating substrate 73 has a sawtooth cross section, and the second electrode 72 is formed on the surface of the sawtooth in the same direction.

  Next, the operation of the fluid actuator 70 will be described. The region 721 covered with the insulating film 74 of the second electrode 72 is far from the first electrode 21, and the exposed region 722 of the second electrode 72 is close to the first electrode 21. At this time, the electric field (or the degree of charging) with respect to the charged fluid 11 is weak in the region 721 and strong in the region 722. In addition to this, in the region 722, the closer to the first electrode 21, the sharper the shape becomes, so that the closer to the first electrode 21, the stronger the electric field. That is, the electric field (or the degree of charging) with respect to the charged fluid 11 varies depending on the position on the second electrode 72.

  In other words, in the present embodiment, a simple stripe-shaped electrode 72 is processed to partially create a strong electric field, thereby facilitating charging and jetting with respect to the charged fluid 11. As shown in the figure, a part of the electrode 72 that becomes + is covered with an insulating film 74, -charged molecules are sucked in a region 721 covered with the insulating film 74, and charged to + in a region 722 where the −charged molecules are exposed. And jet.

  Other configurations, operations, and effects are the same as those in the first to fifth embodiments. According to the present embodiment, the first electrode 21 and the second electrode 72 that are opposed to each other with the charged fluid 11 interposed therebetween are provided, and the electric field (or the degree of charging) with respect to the charged fluid 11 is positioned on the second electrode 72. Since the dielectric constant nonuniformity occurs in the charged fluid 11 between the first electrode 21 and the second electrode 72, the large driving force proportional to the square of the electric field can be obtained. . Therefore, by using a force other than the Coulomb force in addition to or instead of the Coulomb force, it is possible to provide the fluid actuator 70 that realizes an unprecedented large driving force.

  FIG. 5 [1] is a plan view showing a seventh embodiment of the fluid actuator according to the present invention. FIG. 5 [2] is a longitudinal sectional view taken along line II-II in FIG. 5 [1]. Hereinafter, description will be given based on this drawing. 5 that are the same as those in FIG. 1 or FIG. 4 are given the same reference numerals as those in FIG.

  FIG. 5 [1] shows a state where the insulating substrate 12 and the first electrode 21 are removed. The fluid actuator 80 of this embodiment includes one first electrode 21 and a plurality of second electrodes 82, and the plurality of second electrodes 82 are arranged one by one along the flow 111 of the charged fluid 11. The first electrode 21 is provided so as to face all of the plurality of second electrodes 82. Although not shown, a voltage is applied to the first electrode 21 and the second electrode 82, the first electrode 21 is at the voltage Vg, and the second electrode 82 is at the voltage Vp (> Vg).

  The second electrode 82 is non-parallel to the first electrode 21, the region 821 far from the first electrode 21 is covered with the insulating film 84, and the region 822 near the first electrode 21 is exposed. Yes. In the exposed region 822 of the second electrode 82, the planar shape of the base end is a triangle and the planar shape of the distal end is a rectangle. The insulating substrate 83 has a sawtooth cross section, and a second electrode 82 is formed on the surface of the sawtooth in the same direction.

  Next, the operation of the fluid actuator 80 will be described. The region 821 covered with the insulating film 84 of the second electrode 82 is far from the first electrode 21, and the exposed region 822 of the second electrode 82 is close to the first electrode 21. At this time, the electric field (or the degree of charging) with respect to the charged fluid 11 is weak in the region 821 and strong in the region 822. In addition, in the region 822, the shape becomes sharper as it is closer to the first electrode 21, so that the stronger the electric field is, the closer it is to the first electrode 21. That is, the electric field (or the degree of charging) with respect to the charged fluid 11 varies depending on the position on the second electrode 72. In addition, since the planar shape of the tip of the region 822 is rectangular, excessive electric field concentration can be suppressed.

  In other words, in the present embodiment, the tip shape of the electrode 82 that is + is made square, not like the apex of a triangle. This tip portion is a portion that charges and jets the charged fluid 11 with a strong electric field, but is also a portion that is easily discharged and easily damaged. Therefore, the tip portion is widened to increase the durability. Further, the electrode 82 exposes a region where the charged fluid 11 is charged and jetted, covers the other region with the insulating film 84, and protrudes to the convex portion of the insulating substrate 73 so as to easily attract charged molecules. ing. Therefore, in each electrode 82, the portions to be charged and ejected are staggered so that the position where + charged molecules are ejected and the position where −charged molecules are attracted do not collide.

  Other configurations, operations, and effects are the same as those in the first to sixth embodiments. According to the present embodiment, the first electrode 21 and the second electrode 82 that face each other with the charged fluid 11 interposed therebetween are provided, and the electric field (or the degree of charging) with respect to the charged fluid 11 is positioned on the second electrode 82. Since the non-uniformity of the dielectric constant occurs in the charged fluid 11 between the first electrode 21 and the second electrode 82, a large driving force proportional to the square of the electric field can be obtained. . Therefore, by using a force other than the Coulomb force in addition to or instead of the Coulomb force, it is possible to provide the fluid actuator 80 that realizes an unprecedented large driving force.

  FIG. 6 is a sectional view showing an eighth embodiment of the fluid actuator according to the present invention. Hereinafter, description will be given based on this drawing. In FIG. 6, the same reference numerals as those in FIG.

  The fluid actuator 90 of this embodiment includes a plurality of first electrodes 91 and a plurality of second electrodes 92, and the plurality of first electrodes 91 are arranged one by one along the flow 111 of the charged fluid 11. A plurality of second electrodes 92 are arranged one by one along the flow 111 of the charged fluid 11. Each of the plurality of first electrodes 21 is provided so as to be positioned between each of the plurality of second electrodes 82. A voltage is applied to the first electrode 91 and the second electrode 92 so that the first electrode 91 is at a voltage Vg and the second electrode 92 is at a voltage Vp (> Vg).

  The first electrode 91 has a region 911 covered with an insulating film 913 and a region 912 where the first electrode 91 is exposed. Since it is difficult for charges to pass through the insulating film 913, the degree of charging with respect to the charged fluid 11 is low in the region 911 covered with the insulating film 913 and high in the exposed region 912. That is, the degree of charging with respect to the charged fluid 11 varies depending on the position on the first electrode 91.

  Similarly, the second electrode 92 includes a region 921 covered with the insulating film 923 and a region 922 where the second electrode 92 is exposed. Since it is difficult for charges to pass through the insulating film 923, the degree of charging with respect to the charged fluid 11 is low in the region 921 covered with the insulating film 923 and high in the exposed region 922. That is, the degree of charging with respect to the charged fluid 11 varies depending on the position on the second electrode 92.

  In addition, a capacitor made of the insulating film 913 and a capacitor made of the charged fluid 11 are connected in series between the region 911 covered with the insulating film 913 of the electrode 91 and the electrode 92. Therefore, a voltage having a value obtained by dividing the voltage Vg is applied to the charged fluid 11 on the region 911. On the other hand, the voltage Vg is applied to the charged fluid 11 on the exposed region 912 as it is. Therefore, the electric field strength with respect to the charged fluid 11 varies depending on the position on the first electrode 91.

  Similarly, a region 921 covered with the insulating film 923 of the electrode 92 and the electrode 91 are connected in series with a capacitor made of the insulating film 923 and a capacitor made of the charged fluid 11. Therefore, a voltage having a value obtained by dividing the voltage Vp is applied to the charged fluid 11 on the region 921. On the other hand, the voltage Vp is applied as it is to the charged fluid 11 on the exposed region 922. Therefore, the electric field strength with respect to the charged fluid 11 varies depending on the position on the second electrode 92.

  In the present embodiment, the plurality of second electrodes 92 are alternately opposed to the plurality of first electrodes 91 (in a staggered manner), and the plurality of first electrodes 91 and the plurality of second electrodes 92 are Arranged along the flow of the charged fluid. Therefore, the total driving force generated between the plurality of first electrodes 91 and the plurality of second electrodes 92 is greater than that when the first electrode 91 and the second electrode 92 are only one set. Multiple times.

  In other words, in this embodiment, the striped electrode 91 partially covered with the insulating film 913 and the striped electrode 92 partially covered with the insulating film 923 are placed at the relative positions of the flow paths. They are arranged alternately. The electrode 92 and the electrode 91 have the same pitch and are shifted by half a cycle. Therefore, when viewed from the tip of the electrode 92, the electrode 91 is directly above, and a strong electric field is created between the electrodes 91 and 92, and the charged fluid 11 charged to + is ejected and accelerated. In particular, in the region 911 where the electrode 91 is covered with the insulating film 913, even if the charged fluid 11 is touched, no discharge occurs. Therefore, the charged fluid 11 charged to + is accelerated during that time, discharged in the exposed region 912, and charged to-having the opposite polarity. Similarly, the electrode 92 viewed from the tip of the electrode 91 is directly above, and a strong electric field is created, and the charged fluid 11 charged negatively is ejected and accelerated. In this structure, the charged fluid 11 is charged in the reverse polarity in order of + → − → + → − and accelerated each time.

  Other configurations, operations, and effects are the same as those in the first to seventh embodiments. According to the present embodiment, the first electrode 91 and the second electrode 92 that are opposed to each other with the charged fluid 11 interposed therebetween are provided, and the electric field strength (or the degree of charging) with respect to the charged fluid 11 is set on the first electrode 91. Since the charged fluid 11 between the first electrode 91 and the second electrode 92 has a dielectric constant nonuniformity due to the position and the position on the second electrode 92 being different, A large driving force proportional to the square is obtained. Therefore, by using a force other than the Coulomb force in addition to or instead of the Coulomb force, it is possible to provide the fluid actuator 90 that realizes a large driving force that has not been conventionally available.

  FIG. 7 shows an embodiment of a fluid actuator according to the present invention, FIG. 7 [1] is a perspective view, and FIG. 7 [2] is a partial plan view. FIG. 8 is a graph showing measurement results of the fluid actuator of FIG. This example is a more specific embodiment of the first embodiment shown in FIG. In FIG. 7, only the insulating substrate 13 and the second electrode 22 are shown. Hereinafter, description will be made based on FIG. 1 [1], FIG. 7 and FIG.

  In this embodiment, synthetic quartz is used as the insulating substrates 12 and 13. Au / Cr was vapor-deposited on the synthetic quartz at a thickness of 300 nm / 80 nm, respectively, and a planar first electrode 21 and a comb-shaped second electrode 22 were produced by photolithography and etching. As the charged fluid 11, “HFE-7100” manufactured by Sumitomo 3M Co. was used.

  As shown in FIG. 7 [2], the number N of the second electrodes 22, that is, 19 sets of the electrodes 221, 222, the distance D between the electrodes 221 and 222 is 60 μm, the distance Dp between the adjacent second electrodes 22 is 480 μm, The width W of the electrodes 221 and 222 was 120 μm. Also, the height H from the second electrode 22 to the first electrode 21 shown in FIG. 1 [1] was 19 μm.

  At this time, the driving force f is satisfied under the conditions of the voltage Vg = 0 to −700 [V] of the first electrode 21, the voltage Vp = 0 [V] of the electrode 221, and the voltage Vq of the electrode 222 = 360 to 600 [V]. The results of measuring are shown in FIG. In FIG. 8, the horizontal axis represents the electric field E, and the vertical axis represents the driving force f. The electric field E is an electric field generated between the first electrode 21 and the second electrode 22 and is given by E = (Vq−Vg) / 2. The driving force f is the pressure (static pressure) of the charged fluid 11 and is generated in the vertical direction of the electric field E. The direction of the driving force f is the direction of the flow 111 of the charged fluid 11.

  As is clear from FIG. 8, a relationship in which the driving force f is proportional to the square of the electric field E is obtained. From this, the following can be derived. When a voltage is applied so that an electric field is generated in a direction perpendicular to the direction in which the charged fluid flows, the voltage increases and the static pressure increases. If the static pressure is arranged by the electric field in the vertical direction, the static pressure can be arranged by a single curve, and the force is generated by the difference in dielectric constant of fluid molecules polarized by the electric field.

  Although the present invention has been described with reference to the above embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention. Further, the present invention includes a combination of some or all of the configurations of the above-described embodiments as appropriate.

  The fluid actuator according to the present invention can be used in, for example, a pump and a motor.

FIG. 1 [1] is a sectional view showing a first embodiment of a fluid actuator according to the present invention, and FIG. 1 [2] is a sectional view showing a second embodiment of the fluid actuator according to the present invention. 2 [1] is a cross-sectional view showing a third embodiment of the fluid actuator according to the present invention, and FIG. 2 [2] is a cross-sectional view showing a fourth embodiment of the fluid actuator according to the present invention. FIG. 3 [1] is a sectional view showing a fifth embodiment of the fluid actuator according to the present invention, and FIG. 3 [2] is a perspective view showing another example of the fifth embodiment of the fluid actuator according to the present invention. FIG. 4 shows a sixth embodiment of the fluid actuator according to the present invention, FIG. 4 [1] is a plan view, and FIG. 4 [2] is a longitudinal sectional view taken along line II in FIG. FIG. 5 shows a seventh embodiment of the fluid actuator according to the present invention, FIG. 5 [1] is a plan view, and FIG. 5 [2] is a longitudinal sectional view taken along line II-II in FIG. It is sectional drawing which shows 8th embodiment of the fluid actuator which concerns on this invention. FIG. 7 [1] is a perspective view and FIG. 7 [2] is a partial plan view showing an embodiment of a fluid actuator according to the present invention. It is a graph which shows the measurement result of the fluid actuator of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fluid actuator 11 Charged fluid 12 Insulating substrate 13, 13 'Insulating substrate 21 1st electrode 22 2nd electrode 221, 222 Two electrodes 223 One or more electrodes 30 Fluid actuator 32 2nd electrode 321 Covered with insulating film Detached region 322 Exposed region 34 Insulating film 40 Fluid actuator 42 Second electrode 44 Insulating film 50 Fluid actuator 52 Second electrode 54 Insulating film 55 Resistive film 60 Fluid actuator 621-626, 621'-624 ' Electrode 70 Fluid actuator 72 Second electrode 721 Area covered with insulating film 722 Exposed area 74 Insulating film 73 Insulating substrate 80 Fluid actuator 82 Second electrode 821 Area covered with insulating film 822 Exposed area 84 Insulating film 90 fluid actuator 91 first electrode 911 Area covered with insulating film 912 Exposed area 913 Insulating film 92 Second electrode 921 Area covered with insulating film 922 Exposed area 923 Insulating film

Claims (11)

In a fluid actuator that charges and moves a charged fluid by an electric field between electrodes,
A first electrode and a second electrode as the electrodes facing each other across the charged fluid;
The first electrode and the second electrode provide the charged fluid with a force proportional to the square of the electric field applied to the charged fluid between the first electrode and the second electrode;
A fluid actuator. One of the first electrodes and a plurality of the second electrodes, a plurality of the second electrodes being arranged one by one along the flow of the charged fluid, One said first electrode was provided so as to face all,
The fluid actuator according to claim 1.
The second electrode is composed of a plurality of electrodes to which different voltages are applied to the first electrode.
The fluid actuator according to claim 1 or 2, characterized in that The second electrode is composed of two electrodes, and these two electrodes are applied with different voltages with respect to the first electrode.
The fluid actuator according to claim 3. The second electrode has one or more electrodes to which no voltage is applied between the two electrodes.
The fluid actuator according to claim 4. The second electrode has a resistance film provided to connect the two electrodes.
The fluid actuator according to claim 4.
The second electrode has a region covered with an insulating film and an exposed region.
The fluid actuator according to claim 1 or 2, characterized in that The second electrode is non-parallel to the first electrode;
Of the second electrode, the one far from the first electrode is a region covered with the insulating film, and the one near the first electrode is the exposed region.
The fluid actuator according to claim 7. The area of the exposed region decreases as it is closer to the first electrode.
The fluid actuator according to claim 8.
The second electrode is non-parallel to the first electrode;
The fluid actuator according to claim 1 or 2, characterized in that
A plurality of the first electrodes, a plurality of the second electrodes, a plurality of the second electrodes arranged one by one along the flow of the charged fluid, A plurality of the first electrodes are disposed one by one along the flow of the charged fluid so as to be positioned between each other,
The first electrode has a region covered with an insulating film and an exposed region, and the second electrode has a region covered with an insulating film and an exposed region,
The fluid actuator according to claim 1.

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