Actuators, stacked actuators, electrohydrodynamic pumps and stacked pumps

Abstract

We provide a new technology that utilizes the EHD effect. [Solution] In the actuator (10), the EHD pump (13) divides the liquid chamber (11) into a first chamber (14) and a second chamber (15), slides within the liquid chamber (11) according to the flow rate of the insulating working fluid circulating within the liquid chamber (11), and a rod portion (13D) connected to the EHD pump (13) and extending outside the liquid chamber (11) operates along the axial direction of the liquid chamber (11).

Description

Technical Field

[0001] The present invention relates to an actuator, a stacked actuator, an electrohydrodynamic pump, and a stacked pump.

Background Art

[0002] Various pumps are known as liquid transportation devices. Among them, an electrohydrodynamic pump (hereinafter also referred to as an "EHD pump") that utilizes the electrohydrodynamic (EHD) effect is known as a pump that can be disposed inside a pipe serving as a liquid flow path. The EHD pump has a pair of electrodes disposed at specific intervals in the flow direction of the working liquid inside a pipe serving as the flow path of the working liquid. By applying a voltage between the pair of electrodes, the working liquid inside the pipe moves in one direction according to the direction of the electric field.

[0003] Such an EHD pump is known to include a pair of electrode layers disposed at a narrow interval so as to block the pipe inside the pipe serving as the flow path of the working liquid, and the pair of electrode layers having holes through which the working liquid flows (see, for example, Non-Patent Document 1). Alternatively, the EHD pump is known to further include a resin plate-like member having holes communicating with the holes of the electrode layer between the pair of electrode layers (see, for example, Non-Patent Document 2).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

[0005] Because EHD pumps can be installed inside pipes, further consideration is needed regarding various aspects such as size, weight, and performance. Furthermore, since EHD pumps can be installed in liquid flow paths, there is a need to develop a variety of applications tailored to their performance.

[0006] One aspect of the present invention aims to provide a new technology that utilizes the EHD effect. [Means for solving the problem]

[0007] As a means to solve the above problems, the present invention provides the following 1 to 23 embodiments.

[0008] [1] A liquid chamber filled with an insulating working fluid, The system includes an electrohydrodynamic pump that divides the liquid chamber into a first chamber and a second chamber and circulates the working fluid between the first chamber and the second chamber, The first chamber and the second chamber are configured to be deformable according to the amount of working fluid contained within them, and the operating part further includes an operating part that operates in a size corresponding to the amount of deformation of at least one of the first chamber and the second chamber as a result of the deformation caused by the amount of working fluid. Actuator.

[0009] [2] The electrohydrodynamic pump is slidable within the liquid chamber, The actuator according to [1], wherein the operating part is a member connected to the electrohydrodynamic pump and extending outside the liquid chamber.

[0010] [3] One or both of the first chamber and the second chamber include a deformable wall portion in at least part thereof and deform in accordance with the amount of working fluid contained in the chamber, The actuator according to [1], wherein the operating part is the deformable part of the liquid chamber.

[0011] [4] The actuator according to [3], wherein both the first chamber and the second chamber are configured to be deformable according to the amount of working fluid contained in the chamber.

[0012] [5] The actuator according to [4], wherein the electrohydrodynamic pump is flexible.

[0013] [6] A deformable first tube, a tubular electrohydrodynamic pump, and a deformable second tube are arranged in this order from the inside of the tube, The actuator according to [4], wherein at two or more joint points in the circumferential direction of the tubular electrohydrodynamic pump in the cross-section of the pipe, the first pipe is joined to the inner circumferential surface of the tubular electrohydrodynamic pump to form the first chamber, and the second pipe is joined to the outer circumferential surface of the tubular electrohydrodynamic pump to form the second chamber.

[0014] [7] One of the first chamber and the second chamber is configured to be deformable according to the amount of working fluid contained in the chamber, The other of the first chamber and the second chamber is configured to maintain a specific shape regardless of the amount of working fluid contained within the chamber. The actuator described in [3].

[0015] [8] The liquid chamber has two or more first chambers relative to one second chamber, The actuator according to [7], wherein the electrohydrodynamic pump separates at least one of the two or more first chambers from the second chamber.

[0016] [9] The actuator according to any one of [1] to [8], wherein one or both of the first chamber and the second chamber include a sponge member having liquid permeability and elasticity.

[0017] 〔10〕The actuator according to any one of 〔1〕~〔9〕, wherein the working liquid contains a low molecular component having a molecular weight of 1000 or less and a high molecular compound having a number average molecular weight of 10000 or more.

[0018] 〔11〕A stacked actuator in which two or more of the actuators according to any one of 〔1〕~〔10〕 are stacked.

[0019] 〔12〕An electrohydrodynamic pump having a first electrode having a hole through which a liquid flows, and a second electrode having a hole through which a liquid flows and being disposed opposite to the first electrode, where the thicknesses of the first electrode and the second electrode are each 0.2 mm or less, and further having an insulating spacer interposed between the first electrode and the second electrode to restrict the first electrode and the second electrode from approaching each other when a voltage is applied. Electrohydrodynamic pump.

[0020] 〔13〕The electrohydrodynamic pump according to 〔12〕, wherein the spacer has a hole that communicates the hole of the first electrode and the hole of the second electrode.

[0021] 〔14〕The electrohydrodynamic pump according to 〔13〕, wherein the holes of the first electrode, the holes of the second electrode, and the holes of the spacer all have the same opening shape and the same size.

[0022] 〔15〕The electrohydrodynamic pump according to 〔14〕, wherein the holes of at least one of the first electrode and the second electrode include holes having a circular opening shape.

[0023] 〔16〕The electrohydrodynamic pump according to 〔14〕, wherein the holes of at least one of the first electrode and the second electrode include holes having an opening shape formed by connecting a curved portion and a straight portion.

[0024]

[17] The electrohydrodynamic pump according to

[14] , wherein the hole in at least one of the first electrode and the second electrode has an opening shape that includes a polygonal hole.

[0025]

[18] The electrohydrodynamic pump according to

[12] , further comprising an insulating guide tube circumferentially provided on the electrohydrodynamic pump and extending along the opposing directions of the first electrode and the second electrode.

[0026]

[19] The electrohydrodynamic pump according to

[18] , wherein the material of the guide tube is either an inorganic or an organic material or both.

[0027]

[20] The electrohydrodynamic pump according to

[19] , wherein the inorganic material includes a mineral and the organic material includes a resin.

[0028]

[21] An electrohydrodynamic pump according to any one of

[18] to

[20] , wherein the inner dimensions of the guide tube are 0.1 mm or more and 100 mm or less.

[0029]

[22] An electrohydrodynamic pump according to any one of

[12] to

[21] , further comprising a power supply for applying a voltage of 1V to 20000V to the first electrode and the second electrode.

[0030] A stacked pump comprising two or more electrohydrodynamic pumps described in any of

[23] ,

[12] , to

[22] arranged in series. [Effects of the Invention]

[0031] According to one aspect of the present invention, a new technology that utilizes the EHD effect can be provided. [Brief explanation of the drawing]

[0032] [Figure 1] This figure schematically shows the configuration of an actuator according to the first aspect of the present invention. [Figure 2] Figure 1 schematically shows an example of the actuator in operation. [Figure 3]This figure schematically shows the configuration of an actuator according to a second aspect of the present invention. [Figure 4] Figure 3 schematically shows an example of the actuator in operation. [Figure 5] This figure schematically shows the configuration of an actuator according to a third aspect of the present invention. [Figure 6] Figure 5 schematically shows a first example of the actuator in operation. [Figure 7] Figure 5 schematically shows a second example of the actuator in operation. [Figure 8] This figure schematically shows the configuration of an actuator according to the fourth aspect of the present invention. [Figure 9] Figure 8 schematically shows an example of the actuator in operation. [Figure 10] This figure schematically shows one modified example of an actuator according to the fourth aspect of the present invention. [Figure 11] This figure schematically shows the configuration of an actuator according to the fifth aspect of the present invention. [Figure 12] Figure 11 schematically shows a first example of the actuator in operation. [Figure 13] This figure schematically shows a second example of the actuator shown in Figure 11 in an activated state. [Figure 14] This diagram schematically shows the configuration of an actuator according to the sixth aspect of the present invention. [Figure 15] This figure schematically shows the configuration of an actuator according to the seventh aspect of the present invention. [Figure 16] Figure 15 is a schematic plan view showing the configuration of the actuator. [Figure 17] Figure 15 schematically shows a first example of the actuator in operation. [Figure 18] Figure 15 schematically shows a second example of the actuator in operation. [Figure 19]This figure schematically shows a first modified example of an actuator according to the seventh aspect of the present invention. [Figure 20] This figure schematically shows a second modified example of the actuator according to the seventh aspect of the present invention. [Figure 21] This figure schematically shows the configuration of an actuator according to the eighth aspect of the present invention. [Figure 22] Figure 21 is a schematic plan view showing the configuration of the EHD pump in the actuator. [Figure 23] Figure 21 is a schematic diagram illustrating an example of the actuator in operation. [Figure 24] This is a schematic plan view showing a first modified example of the configuration of an EHD pump for an actuator according to the eighth aspect of the present invention. [Figure 25] This is a schematic plan view showing a second modified example of the configuration of an EHD pump for an actuator according to the eighth aspect of the present invention. [Figure 26] This figure schematically shows the configuration of a stacked actuator according to the ninth aspect of the present invention. [Figure 27] Figure 26 schematically shows a first example of a stacked actuator in operation. [Figure 28] Figure 26 schematically shows a second example of the stacked actuator in operation. [Figure 29] This figure schematically shows a first modified example of a stacked actuator according to the ninth aspect of the present invention. [Figure 30] This figure schematically shows a second modified example of a stacked actuator according to the ninth aspect of the present invention. [Figure 31] This figure schematically shows the configuration of a stacked actuator according to the tenth aspect of the present invention. [Figure 32] This figure schematically shows one modified example of a stacked actuator according to the tenth aspect of the present invention. [Figure 33] This is a schematic perspective view showing the configuration of an electrohydrodynamic pump (EHD pump) according to one embodiment of the present invention. [Figure 34]Figure 33 is a side view of the EHD pump. [Figure 35] This figure schematically shows a first example of the planar shape of an electrode in one embodiment of the present invention. [Figure 36] This figure schematically shows a second example of the planar shape of the electrode in one embodiment of the present invention. [Figure 37] This figure schematically shows a third example of the planar shape of the electrode in one embodiment of the present invention. [Figure 38] This figure schematically shows a first example of a combination of electrode planar shape and holes in one embodiment of the present invention. [Figure 39] This figure schematically shows a second example of the planar shape and hole combination of the electrode in one embodiment of the present invention. [Figure 40] This figure schematically shows a third example of the planar shape and hole combination of the electrode in one embodiment of the present invention. [Figure 41] This figure schematically shows a fourth example of the planar shape and hole combination of the electrode in one embodiment of the present invention. [Figure 42] This figure schematically shows a fifth example of the planar shape and hole combination of the electrode in one embodiment of the present invention. [Figure 43] This figure schematically shows a sixth example of the planar shape and hole combination of the electrode in one embodiment of the present invention. [Figure 44] This figure schematically shows the configuration of an EHD pump according to another embodiment of the present invention. [Figure 45] This is a schematic perspective view showing an example of the configuration of a stacked electrohydrodynamic pump (EHD pump) according to an embodiment of the present invention. [Figure 46] This is a schematic perspective view showing another example of the configuration of a stacked electrohydrodynamic pump (EHD pump) according to an embodiment of the present invention. [Figure 47] This figure schematically shows the configuration of a test specimen for testing the performance of an EHD pump according to an embodiment of the present invention. [Figure 48]This figure schematically shows the configuration of a test setup for testing the performance of an EHD pump according to an embodiment of the present invention. [Modes for carrying out the invention]

[0033] One embodiment of the present invention will be described in detail below.

[0034] [Actuator] [First aspect] <Structure> Figure 1 schematically shows the configuration of an actuator according to a first aspect of the present invention. As shown in Figure 1, the actuator 10 has a liquid chamber 11 and an electrohydrodynamic (hereinafter also referred to as "EHD") pump 13.

[0035] The liquid chamber 11 is, for example, a cylindrical container with both ends sealed by a bottom plate and a lid plate. A through hole is formed in the center of the lid plate, and a sealing material 12 is placed in this through hole.

[0036] The liquid chamber 11 has sufficient rigidity to maintain its shape, and the material constituting the liquid chamber 11 (also called "material") is appropriately determined within a range that provides such rigidity. Examples of materials constituting the liquid chamber 11 include inorganic and organic materials such as resins, metals, and ceramics.

[0037] (Working fluid) The liquid chamber 11 is filled with working fluid. The working fluid is an insulating liquid and may be a liquid that flows by the conventionally known EHD effect, and may be one or more types. For example, the conductivity of the working fluid is 1 × 10⁻⁶ -5 S / m or less, especially 1 × 10 -6 It is preferable that the value is less than or equal to S / m, and also 1 × 10 -11 S / m or higher, especially 1 × 10 -10 A value of S / m or higher is preferable from the viewpoint of having electrical properties suitable for the working fluid to flow with the EHD effect.

[0038] The working fluid may contain, for example, low molecular weight components. These low molecular weight components may be one or more types. It is preferable that the molecular weight of the low molecular weight components is 1000 or less from the viewpoint that the working fluid has a viscosity suitable for flow by the EHD effect. Examples of such low molecular weight components with a molecular weight of 1000 or less include aromatic or aliphatic esters and fluorinated solvents.

[0039] Examples of monoesters of this ester include butyl cellosolve acetate, butyl carbitol acetate, 3-methoxy-3-methylbutyl acetate, propylene glycol methyl ether acetate (PMA), propylene glycol ethyl ether acetate, 9,10-epoxybutyl stearate, and 1-ethoxy-2-acetoxypropane.

[0040] Examples of diesters of the ester include dibutyl adipate (DBA), diethyl succinate, diethyl adipate, dibutyl succinate, dibutyl sebacate, diethylhexyl adipate, diethylhexyl sebacate, dibutyl fumarate (DBF), methylacetyl ricinolate (MAR-N), dibutyl itaconate (DBI), 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, dioctyl tetrahydrophthalate, dimethyl phthalate, dibutyl phthalate, dihexyl phthalate, diethylhexyl phthalate, diisononyl phthalate, diisododecyl phthalate, 1,4-diacetoxybutane, 1,5-diacetoxypentane, and 1,6-diacetoxyhexane.

[0041] Examples of triester derivatives of this ester include triacetin and tributyl acetylcitrate.

[0042] In particular, from the viewpoint of having high affinity and solubility for polymer compounds described later, the ester is preferably dibutyl adipate, dibutyl sebacate, 1,6-diacetoxyhexane, diethylhexyl adipate, diethylhexyl phthalate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, or tributyl acetyl citrate, with dibutyl adipate being more preferred.

[0043] Furthermore, the above examples of fluorinated solvents include fluorocarbon-based liquids, such as Noah (registered trademark of ZHEJIANG NOAH FLUOROCHEMICAL) 7100, 7200, and 7300; Novec (registered trademark of 3M) 649, 7100, 7200, 7300, and 7600; and Fluorinert (registered trademark of 3M) FC-3283, FC-40, and FC-43.

[0044] Furthermore, from the viewpoint of increasing the output of the EHD pump 13, the working fluid preferably further contains polymer compounds with a number average molecular weight of 10,000 or more. The polymer compounds may be one or more types, and examples include polymer compounds containing halogens, polyvinyl butyral, polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, nylon 6, polyvinyl alcohol, polycarbonate, polyethylene terephthalate, polyacrylonitrile, and silicone rubber.

[0045] Examples of halogen-containing polymer compounds include polyvinyl chloride, chlorinated polyethylene, polyvinylidene fluoride, polytetrafluoroethylene, and pentafluoroalkoxy fluororesins. Among these, the halogen in the halogen-containing polymer compound is preferably chlorine or bromine, and more preferably chlorine, from the viewpoint of having high affinity and solubility for low molecular weight components in the working fluid. Furthermore, from the viewpoint of structural simplicity and low viscosity, the halogen-containing polymer compound is preferably polyhalogenated vinyl, particularly polyvinyl chloride (PVC).

[0046] The number-average molecular weight of the above polymer compound is preferably 10,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more, from the viewpoint of increasing the discharge pressure and flow rate of the EHD pump 13 with the same applied voltage. Furthermore, the number-average molecular weight of the above polymer compound is preferably 200,000 or less, more preferably 150,000 or less, and even more preferably 100,000 or less, from the viewpoint of maintaining high fluidity of the working fluid.

[0047] From the viewpoint of increasing the discharge pressure and flow rate of the EHD pump 13 at the same applied voltage, the content of the polymer compound in the working fluid is preferably 0.01% by mass or more, and more preferably 0.02% by mass or more. Furthermore, from the viewpoint of preventing the viscosity from becoming too high and improving fluidity, the content of the polymer compound is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

[0048] The working fluid may further contain other components, such as a heat stabilizer, to the extent that the effects of the present invention are obtained. Examples of such heat stabilizers include phosphorus-based heat stabilizers, phenol-based heat stabilizers, amine-based heat stabilizers, sulfur-based heat stabilizers, and inorganic compounds. Examples of such inorganic compounds include inorganic compounds containing Mg, Ba, Zn, or Sn. The content of the heat stabilizer in the working fluid is preferably, for example, 0.01% by mass or less, and more preferably 0.001% by mass or less.

[0049] (EHD pump) The EHD pump 13 has, for example, a disc-like shape and is configured to slide axially within the liquid chamber 11. In this way, the EHD pump 13 divides the liquid chamber 11 into a first chamber 14 on the bottom side and a second chamber 15 on the lid side.

[0050] The EHD pump 13 includes, for example, a disc-shaped insulating spacer 13C, a layered first electrode 13A positioned on one of its main surfaces, and a layered second electrode 13B positioned on the other main surface of the spacer 13C.

[0051] The first electrode 13A and the second electrode 13B are both layers of conductive material, and are constructed by bonding, for example, a metal foil or thin metal plate, such as copper, to the main surface of the spacer 13C with an adhesive. Alternatively, the first electrode 13A and the second electrode 13B may be a plating film formed on the main surface of the spacer 13C, or a coating film of conductive paint containing metal powder such as silver powder. Furthermore, if the spacer 13C is made of resin, the metal foil or thin metal plate may be placed on the main surface by the spacer 13C directly fusing the metal foil or thin metal plate to it. Both the first electrode 13A and the second electrode 13B are connected to a power supply (not shown), and the EHD pump 13 is configured to apply voltage to both electrodes in this way.

[0052] Spacer 13C is a circular sheet made of, for example, an insulating material. This insulating material may be an inorganic material such as silica, alumina, or titanium oxide, or an organic material such as silicone.

[0053] The EHD pump 13 has multiple holes that penetrate the first electrode 13A, the spacer 13C, and the second electrode 13B. The opening shape of the holes is, for example, circular, and the diameter of the holes is, for example, 0.6 mm. The EHD pump 13 circulates the working fluid through these holes by the EHD effect when a voltage is applied to the first electrode 13A and the second electrode 13B. That is, in the actuator 10, the EHD pump 13 is configured to circulate the working fluid in the liquid chamber 11 between the first chamber 14 and the second chamber 15.

[0054] The EHD pump 13 further has a rod portion 13D. The rod portion 13D is a rod-shaped member connected to the EHD pump 13 on the second electrode 13B side. The rod portion 13D extends from the EHD pump 13 through a through hole in the liquid chamber 11 to the outside of the liquid chamber 11 and is configured to slide on the inner circumferential surface of the sealing material 12.

[0055] Furthermore, the first chamber 14 houses a sponge member 16. The sponge member 16 is a resin member having numerous open cells and possesses both liquid permeability and elasticity.

[0056] <Example of operation> Figure 2 schematically shows an example of the actuator 10 in operation. When a voltage is applied between the first electrode 13A and the second electrode 13B, the working fluid in the liquid chamber 11 flows through the holes of the EHD pump 13 due to the EHD effect. As a result, for example, as shown in Figure 2, the working fluid in the first chamber 14 flows into the second chamber 15. As the amount of working fluid in the first chamber 14 decreases and the volume of working fluid in the second chamber 15 increases, the EHD pump 13 moves toward the bottom of the liquid chamber 11 against the elastic force of the sponge member 16. As a result, the first chamber 14 becomes narrower than before the current is applied, and the second chamber 15 becomes wider than before the current is applied. In this way, both the first chamber 14 and the second chamber 15 deform according to the amount of working fluid they contain.

[0057] Furthermore, the EHD pump 13 slides within the liquid chamber 11, moving to a lower position within the liquid chamber 11, causing the tip of the rod portion 13D to lower. In this way, the rod portion 13D, which is connected to the EHD pump 13 and extends outside the liquid chamber 11, operates with a magnitude corresponding to the amount of deformation of the first chamber 14 and the second chamber 15, which are deformed by the amount of working fluid.

[0058] <Main effects and benefits> As described above, the actuator 10 includes a liquid chamber 11 filled with working fluid, and an EHD pump 13 that separates the liquid chamber 11 into a first chamber 14 and a second chamber 15 and circulates the working fluid between the first chamber 14 and the second chamber 15. The first chamber 14 and the second chamber 15 are configured to be deformable according to the amount of working fluid they contain, and the actuator further includes a rod portion 13D that operates in a manner corresponding to the amount of deformation of the first chamber 14 and the second chamber 15 as they are deformed by the amount of working fluid. Therefore, in the actuator 10, the rod portion 13D can be freely extended and retracted by the transport of liquid by the EHD pump 13. Thus, according to this embodiment, a novel actuator 10 that utilizes the EHD effect is provided.

[0059] Furthermore, in the actuator 10, the EHD pump 13 is slidable within the liquid chamber 11, and the rod portion 13D is connected to the EHD pump 13 and extends outside the liquid chamber 11. Therefore, in the actuator 10, the position of the tip of the rod portion 13D can move in proportion to the amount of working fluid being transported. Thus, the actuator 10 is even more effective in producing an operation amount corresponding to the flow rate of the working fluid in the EHD pump 13.

[0060] Furthermore, the actuator 10 includes a sponge member 16 in the first chamber 14 that is permeable and elastic. Therefore, the actuator 10 can suppress the amount the EHD pump 13 extends in the first chamber 14. Consequently, the actuator 10 is even more effective in terms of being able to appropriately define the range of movement of the rod portion 13D.

[0061] Furthermore, in the actuator 10, it is preferable that the working fluid contained in the liquid chamber 11 contains high-molecular-weight compounds with a number average molecular weight of 10,000 or more, in addition to low-molecular-weight components with a molecular weight of 1,000 or less. Having such a configuration in the working fluid further increases the discharge pressure and flow rate of the EHD pump 13 in the actuator 10. Therefore, the actuator 10 is even more effective in terms of achieving high output by increasing the output of the EHD pump 13.

[0062] Other embodiments of the present invention will be described below. In the following descriptions of other embodiments, the same reference numerals will be used to denote members having the same function as those described in the previously described embodiments, and their descriptions will not be repeated.

[0063] [Second aspect] Figure 3 schematically shows the configuration of an actuator according to a second aspect of the present invention. Figure 4 schematically shows an example of the actuator shown in Figure 3 in operation. The actuator of this aspect has the same configuration as the actuator 10 described above, except that it has two EHD pumps in the liquid chamber and rod members extend out of the liquid chamber from each end of the liquid chamber.

[0064] <Structure> As shown in Figure 3, the actuator 20 has a liquid chamber 21 instead of a liquid chamber 11. The liquid chamber 21 has a through hole formed in the center of the bottom plate, and a sealing material 12 is also placed in this through hole. A rod portion 13D is inserted through each of these through holes. The two EHD pumps 13 are each slidably positioned within the liquid chamber 21 in the axial direction. The two EHD pumps 13 divide the inside of the liquid chamber 21 into a first chamber 24 in the center and two second chambers 25, 25 at both ends.

[0065] <Example of operation> For example, if the first electrode 13A of the upper EHD pump 13 in the figure is set as the cathode and the second electrode 13C as the anode, and the first electrode 13A of the lower EHD pump 13 in the figure is set as the anode and the second electrode 13C as the cathode, and a voltage is applied between the electrodes of both pumps, the working fluid in the first chamber 24 will flow into the second chambers 25, 25 at both ends. As a result, the two EHD pumps 13 will move toward each other against the elastic force of the sponge member 26. Consequently, the first chamber 24 will become narrower, the second chamber 25 will become wider, and the rod portions 13D will move into the liquid chambers 21, with their tips positioned closer to the liquid chambers 21. However, the direction of flow may change depending on the type of liquid.

[0066] Thus, the actuator 20 provides the same effect as the actuator 10, and can also generate an operation at each end of the liquid chamber 21 in proportion to the flow rate of the working fluid in the EHD pump 13.

[0067] [Third aspect] <Structure> Figure 5 schematically shows the configuration of an actuator according to a third aspect of the present invention. As shown in Figure 5, the actuator 30 has a liquid chamber 31 with a substantially circular cross-sectional shape and an EHD pump 13 that is positioned to cross the liquid chamber 31 in its central part.

[0068] The liquid chamber 31 is, for example, a flexible tubular member. Figure 3, for example, shows a cross-section of the liquid chamber 31 in the actuator 30, traversing its longitudinal direction. The liquid chamber 31 may be composed of a resin tube that is insulating, thermoplastic, and deformable (flexible). The liquid chamber 31 is filled with the aforementioned working fluid.

[0069] The EHD pump 13 has the configuration described above, except that its shape when viewed from above (also simply called its "planar shape") is roughly rectangular. The EHD pump 13 divides the liquid chamber 31 into two parts, for example, an upper first chamber 34 and a lower second chamber 35.

[0070] The actuator 30 can be manufactured, for example, by inserting the EHD pump 13 into a thermoplastic and deformable resin tube, joining the contact portion of the resin tube with the EHD pump 13 to the side edge of the EHD pump 13 by heat sealing or the like, joining one end of the resin tube to one end edge of the EHD pump 13, injecting working fluid into the first chamber 34 and the second chamber 35, and joining the other end of the resin tube to the other end edge of the EHD pump 13.

[0071] <Example of operation> Figure 6 schematically shows a first example of the actuator 30 in operation. In this first example, the working fluid is moved to the first chamber 34. Figure 7 schematically shows a second example of the actuator 30 in operation. In this second example, the working fluid is moved to the second chamber 35.

[0072] When a voltage is applied between the first electrode 13A and the second electrode 13B of the EHD pump 13, for example with the first electrode 13A as the cathode and the second electrode 13B as the anode, the working fluid in the second chamber 35 flows into the first chamber 34 by the EHD pump 13, as shown in Figure 6. Since the liquid chamber 31 is deformable (flexible), the part on the first chamber 34 side expands and the part on the second chamber 35 side contracts. As a result, a part of the peripheral wall of the liquid chamber 31 on the first chamber 34 side, for example the central part of the first chamber 34, becomes the most deformable working part 31A, and the liquid chamber 31 deforms into a shape that is raised more upwards.

[0073] On the other hand, when a voltage is applied in opposite directions between the first electrode 13A and the second electrode 13B of the EHD pump 13, for example with the first electrode 13A as the anode and the second electrode 13B as the cathode, as shown in Figure 7, the working fluid in the first chamber 34 flows into the second chamber 35, causing the portion on the second chamber 35 side to expand and the portion on the first chamber 34 side to contract. As a result, a portion of the peripheral wall of the liquid chamber 31 on the second chamber 35 side, for example the central part of the second chamber 35, becomes the most deformed operating part 31B, and thus the liquid chamber 31 deforms into a shape that protrudes more downward.

[0074] <Main effects and benefits> The actuator 30 has a liquid chamber 31 and an EHD pump 13 as described above, and the first chamber 34 and the second chamber 35 are configured to be deformable according to the amount of working fluid contained inside them, and the central parts of the first chamber 34 and the second chamber 35 in the liquid chamber 31 are the operating parts 31A and 31B that operate most significantly in proportion to the amount of deformation of the first chamber 34 and the second chamber 35. Thus, according to this embodiment, a novel actuator 30 that utilizes the EHD effect is provided.

[0075] Furthermore, the actuator 30 has a first chamber 34 and a second chamber 35, each containing a deformable wall portion, part of which becomes the operating part 31A and 31B of the actuator 30, and which deforms according to the amount of working fluid contained in the chamber. Therefore, the actuator 30 is even more effective from the viewpoint of being able to construct the operating part with a simple configuration.

[0076] [Fourth aspect] Figure 8 schematically shows the configuration of an actuator according to the fourth aspect of the present invention. The actuator of this aspect has a double structure with a first chamber on the inside and a second chamber on the outside.

[0077] <Structure> As shown in Figure 8, the actuator 40 has a first chamber 44 inside and a second chamber 45 outside of it, and the first chamber 44 and the second chamber 45 constitute a liquid chamber 41. Each of the first chamber 44 and the second chamber 45 is filled with working fluid, and therefore the liquid chamber 41 is also filled with working fluid. Figure 8 shows a cross-section of the actuator 40, and the shape of the actuator 40 when viewed from above is, for example, rectangular.

[0078] The first chamber 44 is formed by two plate-shaped EHD pumps 13, 13 arranged opposite each other, and a first side wall portion 441 and a second side wall portion 442 connecting their sides. The first side wall portion 441 and the second side wall portion 442 are sheet members made of resin that are insulating, thermoplastic, and deformable (flexible).

[0079] The second chamber 45 is formed by a first frame portion 451 and a second frame portion 452 that support the EHD pumps 13, 13 respectively and face each other with the EHD pumps 13, 13 facing inward, and a third side wall portion 453 and a fourth side wall portion 454 that connect the sides of the first frame portion 451 and the second frame portion 452.

[0080] The first frame section 451 and the second frame section 452 are each composed of a flat plate section and ribs extending from both side edges and the central section, and have sufficient rigidity to maintain their shape. The first frame section 451 and the second frame section 452 each support the EHD pump 13 at the tips of the ribs in the central section. The third side wall section 453 and the fourth side wall section 454 are, like the first side wall section 441 and the second side wall section 442, sheet members made of resin that have insulating, thermoplastic, and flexible properties, respectively.

[0081] <Example of operation> Figure 9 schematically shows an example of the actuator 40 in operation. For example, in the upper EHD pump 13 in the figure, the second electrode 13B is the anode and the first electrode 13A is the cathode, and in the lower EHD pump 13 in the figure, the first electrode 13A is the anode and the second electrode 13B is the cathode, and a voltage is applied between both electrodes of the EHD pumps 13, 13. As a result, the working fluid in the first chamber 44 flows into the second chamber 45. Consequently, the volume of the first chamber 44 decreases, and both the first side wall portion 441 and the second side wall portion 442 of the first chamber 44 curve inward, causing the EHD pumps 13, 13 to move closer to each other.

[0082] In the second chamber 45, the working fluid from the first chamber 44 flows in and its volume increases, and as the EHD pumps 13, 13 move closer to each other, the first frame portion 451 and the second frame portion 452 move closer to each other. As a result, the third side wall portion 453 and the fourth side wall portion 454 curve outward.

[0083] In this way, when the actuator 40 is energized in the EHD pumps 13, 13, the first frame portion 451 and the second frame portion 452 move relative to each other in the vertical direction in the figure, and the third side wall portion 453 and the fourth side wall portion 454 deform so that they protrude outward relative to each other. Therefore, the actuator 40 deforms so that the first frame portion 451 or the second frame portion 452 moves relative to each other in the vertical direction, and the central portions of the third side wall portion 453 and the fourth side wall portion 454 move relative to each other in the horizontal direction, by an amount corresponding to the flow rate of the working fluid in the EHD pumps 13, 13.

[0084] The actuator 40 is configured such that both the first chamber 44 and the second chamber 45 can be deformed according to the amount of working fluid contained in the chambers. By increasing or decreasing the amount of working fluid in the first chamber 44 and the amount of working fluid in the second chamber 45, it can be deformed in both the vertical and horizontal directions. Therefore, the actuator 40 is more effective in terms of simultaneously producing movement in two or more different directions by changing the flow rate of the working fluid.

[0085] <Variation> A schematic example of the actuator of this embodiment is shown in Figure 10. Similar to Figure 9, Figure 10 schematically shows an example of the actuator in operation. As shown in Figure 10, the actuator 400 has the same configuration as the actuator 40 described above, except that the first chamber 44 is different.

[0086] The first chamber 44 is formed by interposing a fluid-permeable and deformable sponge member 443 between the EHD pumps 13, 13. A membrane (not shown) is formed on each of the sides of the sponge member 443 facing the third side wall 453 and the fourth side wall 454 to block the working fluid in the first chamber 44 from flowing out to the sides. In this way, the sponge member 443 is configured so that the working fluid contained in the sponge member 443 flows only in the vertical direction in the figure.

[0087] In actuator 400, the EHD pumps 13, 13 approach each other against the elastic force of the sponge member 443. Therefore, actuator 400 is more effective than actuator 40 in that it allows adjustment of the amount of approach between the EHD pumps 13, 13 (the amount of deformation of actuator 400).

[0088] [Fifth aspect] Figure 11 schematically shows the configuration of an actuator according to the fifth aspect of the present invention. In this aspect, the entire actuator is deformable.

[0089] <Structure> As shown in Figure 11, the actuator 50 includes an EHD pump 53, a first covering portion 541 that covers one main surface side of the EHD pump 53 with a gap between them, and a second covering portion 551 that covers the other main surface side of the EHD pump 53 with a gap between them. The first covering portion 541 and the second covering portion 551 constitute a liquid chamber 51. The space formed by the EHD pump 53 and the first covering portion 541 is filled with working fluid, and this space is the first chamber 54. The space formed by the EHD pump 53 and the second covering portion 551 is also filled with working fluid, and this space is the second chamber 55.

[0090] The EHD pump 53 has a first electrode 13A, a second electrode 13B, and a spacer 53C. The spacer 53C has a configuration in which the aforementioned holes are formed in a sheet member made of an insulating and flexible resin (e.g., silicone), and otherwise has the same configuration as the EHD pump 13 described above. In this way, the EHD pump 53 is flexible.

[0091] The first covering portion 541 is a cup-shaped member with a cross-sectional shape, and its peripheral edge is joined to the peripheral edge on one main surface side of the EHD pump 53. The first covering portion 541 is made of a resin (for example, silicone) that has insulating and flexible properties.

[0092] The second covering portion 551, like the first covering portion 541, has a cup-shaped cross-section, and its peripheral edge is joined to the peripheral edge on the other main surface side of the EHD pump 53. The second covering portion 551 is also made of a resin (for example, silicone) that has insulating and flexible properties.

[0093] <Example of operation> Figure 12 schematically shows a first example of the actuator 50 in operation. In this first example, the working fluid is moved to the first chamber 54. Figure 13 schematically shows a second example of the actuator 50 in operation. In this second example, the working fluid is moved to the second chamber 55.

[0094] When a voltage is applied between the first electrode 13A and the second electrode 13B of the upper EHD pump 53 in the figure, for example with the first electrode 13A as the cathode and the second electrode 13B as the anode, the working fluid in the second chamber 55 flows into the first chamber 54 by the EHD pump 53, as shown in Figure 12. Since both the liquid chamber 51 and the EHD pump 53 are deformable in the actuator 50, the first chamber 54 expands and the second chamber 55 contracts, and as a result, the actuator 50 curves overall so that it is convex toward the first chamber 54 side (upwards in the figure).

[0095] When a voltage is applied in opposite directions between the first electrode 13A and the second electrode 13B of the lower EHD pump 53 in the figure, for example with the first electrode 13A as the anode and the second electrode 13B as the cathode, the working fluid in the first chamber 54 flows into the second chamber 55, causing the second chamber 55 to expand and the first chamber 54 to contract, as shown in Figure 13. As a result, the actuator 50 curves overall so that it is convex toward the second chamber 55 side (downward in the figure).

[0096] Since the actuator 50 includes a flexible EHD pump 53, it is even more effective in deforming the entire actuator 50 to a shape corresponding to the amount of movement of the insulating fluid.

[0097] [Sixth aspect] Figure 14 schematically shows the configuration of an actuator according to the sixth aspect of the present invention. The actuator in this aspect is tubular.

[0098] <Structure> As shown in Figure 14, the actuator 60 is composed of an inner tube 641, an EHD pump 63, and an outer tube 651 from the inside out. Both the inner tube 641 and the outer tube 651 are made of a resin (e.g., silicone) that has insulating and flexible properties. The EHD pump 63 has the same configuration as described above, except that the spacer 63C is tubular.

[0099] The inner tube 641 is joined axially to the first electrode 13A of the EHD pump 63 at four equally spaced joints 601 to 604 in the circumferential direction of the cross-section of the actuator 60, but is not joined to the first electrode 13A in other parts. The inner tube 641 has four first chambers formed on the inner circumference side of the EHD pump 63: a first chamber 64A extending axially between joints 601 and 602, a first chamber 64B extending axially between joints 602 and 603, a first chamber 64C extending axially between joints 603 and 604, and a first chamber 64D extending axially between joints 604 and 601.

[0100] The outer tube 651 is joined axially to the second electrode 13B of the EHD pump 63 at each of the joints 601 to 604, but is not joined to the second electrode 13B at other points. The outer tube 651 forms four second chambers on the outer circumference of the EHD pump 63: a second chamber 65A extending axially between joints 601 and 602, a second chamber 65B extending axially between joints 602 and 603, a second chamber 65C extending axially between joints 603 and 604, and a second chamber 65D extending axially between joints 604 and 601.

[0101] As a result, a liquid chamber 61A containing a first chamber 64A, an EHD pump 63, and a second chamber 65A is formed between joints 601 and 602; a liquid chamber 61B containing a first chamber 64B, an EHD pump 63, and a second chamber 65B is formed between joints 602 and 603; a liquid chamber 61C containing a first chamber 64C, an EHD pump 63, and a second chamber 65C is formed between joints 603 and 604; and a liquid chamber 61D containing a first chamber 64D, an EHD pump 63, and a second chamber 65D is formed between joints 604 and 601. Each liquid chamber is filled with working fluid. Furthermore, each liquid chamber is sealed at both ends of the actuator 60. In this way, the actuator 60 is configured such that liquid chambers extend axially along the tubular EHD pump 63 at two or more circumferential positions.

[0102] The actuator 60 can be manufactured by (1) placing an insulating and flexible resin sheet on an EHD pump which has a rectangular shape when viewed from above and is flexible, and its first electrode; (2) joining the resin sheet to the first electrode in a linear fashion at both side edges of the first electrode and at three parallel and equally spaced locations thereto; (3) similarly placing the resin sheet on the second electrode of the EHD pump and joining the resin sheet to the second electrode in a linear fashion at both side edges of the second electrode and at three parallel and equally spaced locations thereto; (4) rolling up the EHD pump and joining the side edges together to form a tubular object; (5) sealing the resin sheet at one end of the tubular object; (6) filling each of the four pockets in the resin sheet formed in the circumferential direction of the tubular object with working fluid from the other end of the tubular object; and (7) sealing the resin sheet at the other end of the tubular object.

[0103] <Example of operation> When a voltage is applied between the first electrode 13A and the second electrode 13B of the EHD pump 63, for example with the first electrode 13A as the anode and the second electrode 13B as the cathode, the working fluid in the second chambers 65A, 65B, 65C, and 65D flows into the first chambers 64A, 64B, 64C, and 64D, causing each of the first chambers 64A, 64B, 64C, and 64D to expand. As a result, the conduit formed on the inner circumference of the actuator 60 is blocked by the first chambers 64A, 64B, 64C, and 64D. In this way, the actuator 60 can function as a valve that opens and closes the conduit.

[0104] As is clear from the above description, the actuator 60 has a deformable inner tube 641, a tubular EHD pump 63, and a deformable outer tube 651 in this order from the inside of the tube. At four joints 601 to 604 in the circumferential direction of the tubular EHD pump 63 in the cross-section of the tube, the inner tube 641 is joined to the inner circumferential surface of the EHD pump 63 to form the first chambers 64A, 64B, 64C, and 64D, and the outer tube 651 is joined to the outer circumferential surface of the EHD pump 63 to form the second chambers 65A, 65B, 65C, and 65D. Therefore, it is suitable from the viewpoint of configuring an actuator that has the function of a valve.

[0105] In addition, the actuator 60 may have the EHD pump 63 insulated along the joints 601 to 604. In this case, the flow rate of the working fluid can be controlled independently in each of the liquid chambers 61A, 61B, 61C, and 61D, and the shape of each liquid chamber can be appropriately changed.

[0106] [Seventh aspect] Figure 15 schematically shows the configuration of an actuator according to the seventh aspect of the present invention. Figure 16 also schematically shows the configuration of the actuator. In this aspect, only one main surface side of the EHD pump is deformable.

[0107] <Structure> As shown in Figure 15, the actuator 70 has EHD pumps 731 and 732, first covering portions 741A and 741B that are spaced apart and cover one main surface side of each EHD pump 731 and 732, and a second covering portion 751 that is spaced apart and covers the other main surface side of the EHD pumps 731 and 732.

[0108] When viewed from above, the EHD pumps 731 and 732 are each square in shape and are connected via an insulating partition plate 13E. Each of the EHD pumps 731 and 732, which are the divided parts when the aforementioned EHD pump 13 is divided in two by the partition plate 13E, is independently connected to a power supply.

[0109] The first covering portions 741A and 741B are, for example, dome-shaped members and are made of a resin that has insulating and flexible properties. The first covering portions 741A and 741B are joined to one main surface of each of the EHD pumps 731 and 732 such that their peripheral edges are inscribed within the respective planar shapes (squares) of the EHD pumps 731 and 732.

[0110] The second covering portion 751 is composed of a flat plate portion that has a rectangular shape when viewed from above, and side walls that rise from its edge, and has sufficient rigidity to maintain its shape. The side walls of the edge of the second covering portion 751 support the EHD pumps 731 and 732 by contacting their edges.

[0111] The first covering portion 741A constitutes the first chamber 74A, and the first covering portion 741B constitutes the first chamber 74B. The second covering portion 751 constitutes the second chamber 75. The first chamber 74A, the first chamber 74B, and the second chamber 75 are filled with working fluid, and the first chamber 74A, the first chamber 74B, and the second chamber 75 constitute the liquid chamber 71.

[0112] Thus, in the actuator 70, the first chambers 74A and 74B are configured to deform according to the amount of working fluid contained within them, while the second chamber 75 is configured to maintain a specific shape regardless of the amount of working fluid contained within it. Furthermore, the liquid chamber 71 has two or more first chambers 74A and 74B for each second chamber 75, and the EHD pumps 731 and 732 separate the first chambers 74A and 74B from the second chamber 75.

[0113] <Example of operation> Figure 17 schematically shows a first example of the actuator 70 in operation. The first example is one in which the working fluid is moved to one of the first chambers 74A. Figure 18 schematically shows a second example of the actuator 70 in operation. The second example is one in which the working fluid is moved to the other first chamber 74B.

[0114] When a voltage is applied between the first electrode 13A and the second electrode 13B of the EHD pump 731, for example with the first electrode 13A as the cathode and the second electrode 13B as the anode, and when a voltage is applied between the first electrode 13A and the second electrode 13B of the EHD pump 732, for example with the first electrode 13A as the anode and the second electrode 13B as the cathode, the working fluid in the first chamber 74B flows into the first chamber 74A via the second chamber 75, causing the first chamber 74A to expand and deform upward, and the first chamber 74B to contract and deform downward.

[0115] Conversely, if a voltage is applied between the first electrode 13A and the second electrode 13B of the EHD pump 731, for example with the first electrode 13A as the anode and the second electrode 13B as the cathode, and a voltage is applied between the first electrode 13A and the second electrode 13B of the EHD pump 732, with the first electrode 13A as the cathode and the second electrode 13B as the anode, the working fluid in the first chamber 74A flows into the first chamber 74B via the second chamber 75, causing the first chamber 74B to expand and deform upward, and the first chamber 74A to contract and deform downward.

[0116] Thus, the actuator 70 is even more effective from the viewpoint that it can alternately protrude two parallel first chambers 74A and 74B, and can configure two or more independent operating points in the planar direction.

[0117] <Variation> In this embodiment, the rectangular EHD pump is divided into two by an insulating partition plate 1E. However, as shown in Figure 19, the EHD pump 13, which has a rectangular (e.g., square) planar shape, may be divided into four EHD pumps 131 to 134 by two insulating partition plates 13E, 13E that are orthogonal to each other. Four first covering parts 741A, 741B, 741C, and 741D may be arranged corresponding to the divided EHD pumps to form four first chambers 74A, 74B, 74C, and 74D.

[0118] In such an actuator 701, for example, by applying voltage in the same direction of current to EHD pumps 131 and 133, and applying voltage in the opposite direction of current to EHD pumps 132 and 134, it is possible to deform the first coating portions 741A and 741C and the first coating portions 741B and 741D to alternately protrude and retract as shown in Figures 17 and 18.

[0119] Furthermore, the actuator 701 can also deform the first coating portions 741A, 741B, 741C, and 741D by, for example, applying a voltage of +V1 to the EHD pump 132, a voltage of +V2 to the EHD pumps 131 and 134, and a voltage of -V3 (V3>V1>V2) to the EHD pump 133, such that the first coating portion 741B protrudes the most, followed by the first coating portions 741A and 741D, and the first coating portion 741C protrudes the least.

[0120] Furthermore, in this embodiment, as shown in Figure 20, the EHD pump 13, which has a triangular (e.g., equilateral triangle) planar shape, may be divided into three EHD pumps 131, 132, and 133 by three insulating partition plates 13E, and three first covering parts 741A, 741B, and 741C may be arranged corresponding to the divided EHD pumps to form three first chambers 74A, 74B, and 74C.

[0121] In such an actuator 702, for example, by applying voltage in the same direction of current to EHD pumps 131 and 132 and voltage in the opposite direction of current to EHD pump 133, it is possible to deform the first coating portions 741A and 741B and the first coating portion 741C so that they alternately protrude and retract, as shown in Figures 17 and 18.

[0122] Furthermore, in the embodiment shown in Figures 15-18 above, voltage can be applied independently to each EHD pump after division by the partition plate. However, to the extent that a desired pattern of protruding and retracting two or more first chambers can be realized, one or more EHD pumps after division can be omitted or replaced with a permeable plate-like member. For example, if it is sufficient to be able to transform into only two forms, the form shown in Figure 15 and the form shown in Figure 17, it is possible to omit one of the EHD pumps 731 and 732.

[0123] [Eighth aspect] Figure 21 schematically shows the configuration of an actuator according to the eighth aspect of the present invention. Figure 22 schematically shows the configuration of the EHD pump in the actuator shown in Figure 21 when viewed from above. The actuator of this aspect has a top plate portion that spans two or more first chambers, and this top plate portion is the operating part of the actuator.

[0124] <Structure> As shown in Figure 21, the actuator 80 has EHD pumps 831 and 832, sponge members 841A and 841B joined to one main surface of each of the EHD pumps 831 and 832, a top plate portion 86 spanning across the top surfaces of each of them, and a covering portion 851 that covers the other main surface of the EHD pumps 831 and 832 with a gap between them.

[0125] The EHD pumps 831 and 832 are configured in the same way as the EHD pumps 731 and 732 described above, except that their planar shape is approximately semicircular. The covering portion 851 is configured in the same way as the second covering portion 751 described above, except that its planar shape is approximately circular.

[0126] The sponge members 841A and 841B are, for example, roughly semi-cylindrical in shape and are made of a resin that is insulating and flexible. The sponge members 841A and 841B are joined to one main surface of each of the roughly semi-circular EHD pumps 831 and 832, respectively, so as to overlap each of the EHD pumps 831 and 832. The circumferential surfaces of the sponge members 841A and 841B are formed with a film that blocks the passage of liquid.

[0127] The top plate portion 86 is a plate-like member having a roughly circular planar shape and possessing sufficient rigidity to maintain its shape. The top plate portion 86 is joined to the top surfaces of the sponge members 841A and 841B, respectively.

[0128] In the actuator 80, the sponge member 841A and the top plate portion 86 constitute the first chamber 84A, and the sponge member 841B and the top plate portion 86 constitute the first chamber 84B. The covering portion 851 constitutes the second chamber 85. The first chamber 84A, the first chamber 84B, and the second chamber 85 are filled with working fluid, and the first chamber 84A, the first chamber 84B, and the second chamber 85 constitute the liquid chamber 81. Thus, in the actuator 80, the first chambers 84A and 84B each contain sponge members 841A and 841B, respectively, which have both fluid permeability and elasticity.

[0129] <Example of operation> Figure 23 schematically shows an example of the actuator 80 in operation. A voltage is applied between the first electrode 13A and the second electrode 13B of the EHD pump 831, for example, with the first electrode 13A as the cathode and the second electrode 13B as the anode. A voltage is also applied between the first electrode 13A and the second electrode 13B of the EHD pump 832, with the first electrode 13A as the anode and the second electrode 13B as the cathode. As a result, as shown in Figure 23, the working fluid in the first chamber 84A flows into the first chamber 84B via the second chamber 85, causing the first chamber 84A to contract and deform downwards, and the first chamber 84B to expand and deform upwards. Consequently, the top plate 86, which was previously nearly horizontal, tilts diagonally.

[0130] Thus, the actuator 80 is composed of sponge members 841A and 841B in each of its first chambers 84A and 84B, and since it can have a relatively wide top surface, it is suitable for supporting further members such as the top plate portion 86. Therefore, the actuator 80 is even more effective from the viewpoint of using the further member as the moving part.

[0131] <Variation> In actuator 80, the EHD pump, which has a roughly circular planar shape, is divided into two by a partition plate. However, as shown in Figure 24, the EHD pump 13 may be divided into three EHD pumps 831-833 by three partition plates 13E, 13E, and each of the three first chambers corresponding to the divided EHD pumps may be composed of a sponge member and an integrated top plate that spans them.

[0132] Alternatively, in the actuator 80, as shown in Figure 25, the EHD pump 13 may be divided into four EHD pumps 831-834 by two partition plates 13E, 13E, and each of the four first chambers corresponding to the divided EHD pumps may be composed of a sponge member and an integrated top plate that spans them.

[0133] In this configuration, where the EHD pump and the first chamber are divided into multiple sections, more complex movements become possible, such as rotating the top plate section, which is the operating part, around the central axis while tilted circumferentially. A larger number of divisions is advantageous in terms of making these complex movements smoother.

[0134] [Stacked Actuator] [Ninth aspect] Figure 26 schematically shows the configuration of a stacked actuator according to the ninth aspect of the present invention. As shown in Figure 26, the stacked actuator 100 is constructed by stacking three actuators 70 of the seventh aspect described above. In this aspect, the reference numerals A, B, and C are further added to the reference numerals of each of the stacked actuators from bottom to top.

[0135] In the stacked actuator 100, actuators 70A, 70B, and 70C are configured to deform integrally. For example, the first covering portions 741A and 741B of actuator 70A may be joined to the second covering portion 751 of actuator 70B, and the first covering portions 741A and 741B of actuator 70B may be joined to the second covering portion 751 of actuator 70C. Alternatively, actuators 70A, 70B, and 70C may be inserted into a flexible tube and held adjacent to each other.

[0136] Furthermore, in the stacked actuator 100, wires are connected to the EHD pumps 731 and 732 of actuators 70A, 70B, and 70C, respectively, and each of the EHD pumps 731 and 732 is configured to operate independently.

[0137] Figure 27 schematically shows a first example of the stacked actuator 100 in operation, and Figure 28 schematically shows a second example of the stacked actuator 100 in operation. When the EHD pumps 731 and 732 are operated to circulate the working fluid from the first chamber 74B to the second chamber 75, and from the second chamber 75 to the first chamber 74A, in actuators 70A, 70B, and 70C respectively, the stacked actuator 100 bends as a whole toward the first chamber 74B side (left side in the figure), as shown in Figure 27. Conversely, when the EHD pumps 731 and 732 are operated to circulate the working fluid from the first chamber 74A to the second chamber 75, and from the second chamber 75 to the first chamber 74B, as shown in Figure 28, the stacked actuator 100 bends as a whole toward the first chamber 74A side (right side in the figure).

[0138] The stacked actuator 100 can be appropriately deformed according to the flow rate of the working fluid in the first chambers 74A and 74B through which the working fluid flows in the connected actuators 70A, 70B, and 70C. Since the stacked actuator 100 is composed of multiple actuators 70 stacked on top of each other, it is even more effective in terms of diversifying the amount of actuator operation and movement.

[0139] <Variation> Figure 29 schematically shows a first modified example of the stacked actuator of this embodiment. The stacked actuator 110 shown in Figure 29 further has a top plate portion 111, the first covering portions 741A and 741B of the actuator 70C are formed in a cylindrical shape, and the EHD pumps 731 and 732 are connected to the top plate portion 111. Otherwise, the stacked actuator 110 is configured in the same way as the stacked actuator 100. The stacked actuator 110 is preferable from the viewpoint of the linear operating amount of the actuator.

[0140] Figure 30 schematically shows a second modified example of the stacked actuator of this embodiment. The stacked actuator 120 shown in Figure 30 further has a top plate portion 111, and actuators 70B and 70C do not have a second covering portion 751, the first covering portions 741A and 741B are formed in a cylindrical shape, and EHD pumps 731 and 732 are connected to each other or to the top plate portion 111. Otherwise, the stacked actuator 120 is configured in the same way as the stacked actuator 100. In this way, in the stacked actuator 120, the first chambers 74 of all actuators 70 are connected in series via the second covering portion 751 of actuator 70A. Therefore, since all stacked actuators 70 share the working fluid, it is possible to operate them at a larger rate than the sum of the operations of each actuator having a second covering portion. Accordingly, the stacked actuator 120 is more preferable from the viewpoint of a more compact configuration and from the viewpoint of achieving a larger range of motion.

[0141] [Tenth aspect] Figure 31 schematically shows the configuration of a stacked actuator according to the tenth aspect of the present invention. As shown in Figure 31, the stacked actuator 200 is constructed by stacking three actuators 80 of the eighth aspect described above. The stacked actuator 200 operates in the same manner as the stacked actuator 100 described above and produces the same effects.

[0142] Furthermore, a schematic example of a modified stacked actuator of this embodiment is shown in Figure 32. As shown in Figure 32, the stacked actuator 210 has the same configuration as the stacked actuator 200, except that, similar to the modifications made to the stacked actuator 120 compared to the stacked actuator 100 described above, the actuators 80B and 80C do not have a covering portion 851, and the sponge members 841A and 841B connect the EHD pumps 131 and 132 to each other or to the EHD pumps 131 and 132 to the top plate portion 111. Therefore, the stacked actuator 210 is more preferable to the stacked actuator 200 in terms of a more compact configuration and in terms of achieving greater movement.

[0143] While known EHD pumps that utilize the EHD effect can be used in the actuators and stacked actuators of the present invention as described above, the EHD pumps according to the embodiments of the present invention described below are preferred from the viewpoint of high output and compactness. The EHD pumps according to embodiments of the present invention will be described below.

[0144] [Electrohydrodynamic (EHD) pumps] [composition] Figure 33 schematically shows the configuration of an electrohydrodynamic pump (EHD pump) according to one embodiment of the present invention. Figure 34 shows a side view of the EHD pump. As shown in Figures 33 and 34, the EHD pump 1 has an insulating disc-shaped support portion 2, a first electrode 3 arranged on one main surface of the support portion 2, and a second electrode 4 arranged on the other surface of the support portion 2.

[0145] The first electrode 3 has a circular flow channel 5 located in the center of the planar shape of the support portion 2, and a substantially rectangular connecting portion 6 extending radially outward from the flow channel 5. The second electrode 4 also has the same planar shape as the first electrode 3. However, the connecting portion 8 of the second electrode 4 extends radially outward from the portion of the flow channel 7 of the second electrode 4 that faces the connecting portion 6 of the first electrode 3.

[0146] The flow path portion 7 of the first electrode 3 has multiple holes 9 that penetrate the EHD pump 1 in the direction of thickness. In other words, the holes 9 extend from the first electrode 3 through the support portion 2 to the second electrode 4, and can serve as a flow path for insulating working fluid.

[0147] Furthermore, since the support portion 2 has the electrodes on both main surfaces, it defines the position between the electrodes and restricts their separation and proximity.

[0148] Thus, the EHD pump 1 includes a first electrode 3 having a hole 9 through which liquid flows, a second electrode 4 having a hole 9 and positioned opposite the first electrode 3, and an insulating support part (spacer) 2 interposed between the first electrode 3 and the second electrode 4 to restrict the first electrode 3 and the second electrode 4 from approaching each other when a voltage is applied.

[0149] <Electrode> The first electrode 3 and the second electrode 4 only need to have sufficient conductivity to exhibit the EHD effect, and are composed of materials that exhibit such conductivity. For example, the conductivity of the first electrode 3 and the second electrode 4 is preferably 100 S / m, more preferably 10,000 S / m, and even more preferably 1,000,000 S / m, from the viewpoint of exhibiting sufficient conductivity to exhibit the EHD effect. The materials of the first electrode 3 and the second electrode 4 may be the same or different. Examples of such materials include metals and graphite.

[0150] Furthermore, the forms of the first electrode 3 and the second electrode 4 can be appropriately determined within the range that exhibits the EHD effect, and examples include thin sheets of conductive material such as metal, foils, braided metal wires, plating layers, and coatings of paint containing powder of conductive material. The first electrode 3 and the second electrode 4 may be bonded to the support part 2 by adhesive, or they may be formed directly on the main surface as a plating film, or they may be coatings of conductive paint containing metal powder, or they may be directly fused to the support part 2 if the support part 2 is made of resin.

[0151] If the thickness of the first electrode 3 and the second electrode 4 is too thick, it may cause pressure loss. From the viewpoint of suppressing pressure loss, the thickness of the first electrode 3 and the second electrode 4 is preferably 0.2 mm or less, more preferably 0.1 mm or less, and more preferably 0.05 mm or less, respectively. The thicknesses of the first electrode 3 and the second electrode 4 may be the same or different. The lower limit of the thickness of the first electrode 3 and the second electrode 4 can be appropriately determined within the range in which the EHD effect is exhibited. From the viewpoint of fully exhibiting the desired EHD effect, the thickness of the first electrode 3 and the second electrode 4 is preferably 0.00001 mm or more, more preferably 0.0001 mm or more, and even more preferably 0.001 mm or more.

[0152] The planar shapes of the first electrode 3 and the second electrode 4 can be selected as appropriate. A schematic example of the planar shape of the electrodes is shown in Figure 35, a schematic example in Figure 36, and a schematic example in Figure 37. For example, as shown in Figure 35, the planar shapes of both the first electrode 3 and the second electrode 4 may be circular. A circular planar shape is preferable from the viewpoint of uniformly circulating the working fluid within the circular pipe when the EHD pump 1 is used as a power source to flow the working fluid through a circular pipe. Also, as shown in Figure 36, the planar shapes of both the first electrode 3 and the second electrode 4 may be approximately semicircular. Such approximately semicircular electrodes are preferable from the viewpoint of dividing the circular pipe along the axial direction. Furthermore, as shown in Figure 37, in accordance with the annular shape of the support portion 2, the planar shapes of both the first electrode 3 and the second electrode 4 may be annular shapes located between the inner and outer edges of the support portion 2. Such annular electrodes are preferable from the viewpoint of constructing a double ring structure within the circular tube described above.

[0153] Furthermore, six examples of electrode planar shapes and hole combinations are schematically shown in Figures 38 to 43. As shown in these figures, the first electrode 3 and the second electrode 4 may be constructed by weaving metal wire or thin wires into a rectangular grid, and their overall planar shape may be circular as shown in Figure 38, or rectangular such as a square as shown in Figure 39. Alternatively, the first electrode 3 and the second electrode 4 may be constructed by weaving metal wire or thin wires into a hexagonal grid, and their overall planar shape may be circular as shown in Figure 40, rectangular such as a square as shown in Figure 41, or roughly semi-ring-shaped as shown in Figure 42. Alternatively, the first electrode 3 and the second electrode 4 may be constructed by weaving metal wire or thin wires so that the shape of the mesh is circular (or roughly circular), and their overall planar shape may be rectangular as shown in Figure 43.

[0154] (hole) The holes 9 in the EHD pump 13 become the flow path for the working fluid when the EHD pump 13 is operating. Regarding the opening shape of the holes 9, it is generally preferable that the perimeter of the holes 9 is shorter than the opening area of ​​the holes 9, from the viewpoint of reducing the resistance of the working fluid passing through the opening of the holes 9. From this viewpoint, it is preferable that the opening shape of the holes 9 is circular. On the other hand, regarding the opening shape of the holes 9, it is preferable that the perimeter is longer than the opening area of ​​the holes 9, from the viewpoint of increasing the output of the EHD pump 13. From this viewpoint, it is preferable that the opening shape of the holes 9 is a shape in which a curved portion and a straight portion are connected, and it is more preferable that the opening shape of the holes 9 is polygonal.

[0155] Furthermore, the diameter of the holes 9 in the EHD pump 1 can be appropriately determined within a range in which the EHD effect can be obtained. If the diameter is too large, the EHD effect may be insufficient, and if the diameter is too small, the pressure loss in the flow of the working fluid tends to increase. From the viewpoint of suppressing pressure loss, the diameter of the holes 9 is preferably 0.1 μm or larger, more preferably 1 μm or larger, and even more preferably 10 μm or larger. Also, from the viewpoint of enhancing the EHD effect, the diameter of the holes 9 is preferably 10,000 μm or less, more preferably 5,000 μm or less, and even more preferably 1,000 μm or less.

[0156] The diameter of hole 9 is a dimension representing the size of the opening of hole 9. If it is circular, it is the diameter; otherwise, it may be the major axis or the diameter of the circumscribed circle. Furthermore, the diameter of hole 9 may be a numerical value that appropriately represents the influence that the size of hole 9 has on the flow of the working fluid. It may be the average value or the maximum value at one electrode.

[0157] <Spacer> The first electrode 3 and the second electrode 4 in the EHD pump 1 are both thin. Therefore, when voltage is applied, there is a risk that they will attract each other and come into contact. The EHD pump 1 has a plate-shaped support portion 2 interposed between the two electrodes, which restricts the first electrode 3 and the second electrode 4 from coming too close to each other when voltage is applied. In this way, the support portion 2 functions as a spacer to maintain the distance between the electrodes in the EHD pump 1.

[0158] The form of such a spacer can be appropriately determined in the present invention within a range that can restrict the proximity between the two electrodes. For example, the spacer may be a plurality of spheres interposed between the two electrodes, a plurality of columnar bodies, or one or more annular frames. Furthermore, it is sufficient that it has insulating properties from the viewpoint of preventing current flow between the two electrodes. In addition, the spacer as a whole may have fluid permeability from the viewpoint of realizing the flow of the working fluid by the EHD effect, and it is preferable that it has a hole that connects the hole of the first electrode 3 and the hole of the second electrode 4.

[0159] The fluid channels in such spacers may be finer or coarser than the holes in the electrodes. Examples of spacers that form such fine channels include sponge materials and monolithic porous materials such as sintered metal oxides.

[0160] In particular, as shown in Figures 33 and 34, it is preferable from the viewpoint of ensuring smooth flow of the working fluid and from the viewpoint of reducing pressure loss that the holes in the spacer have the same size and opening shape as the holes in the first electrode and the second electrode. Furthermore, from the viewpoint of reducing pressure loss, it is even more preferable that the opening shapes of the holes in the first electrode, the second electrode, and the spacer are circular.

[0161] The dimensions of the spacer in the opposing direction between the first electrode and the second electrode (or its thickness in the case of the support portion 2 mentioned above) can be appropriately set according to the desired EHD effect. If the dimensions are too small, the EHD effect may be insufficient, and the operating conditions under which the EHD effect can be obtained in the EHD pump 1 may become narrower. On the other hand, if the dimensions are too large, the EHD effect may be insufficient. From the viewpoint of fully exhibiting the desired EHD effect, the dimensions of the spacer in the opposing direction between the first electrode and the second electrode are preferably 0.001 mm or more, more preferably 0.01 mm or more, even more preferably 0.1 mm or more, preferably 100 mm or less, more preferably 10 mm or less, and even more preferably 1 mm or less.

[0162] [Further structure] An EHD pump according to an embodiment of the present invention may further have other configurations other than those described above, to the extent that the effects of the present invention are obtained.

[0163] <Guide tube> For example, an EHD pump according to an embodiment of the present invention may further have an insulating guide tube 17 surrounding the EHD pump 1, as shown in Figure 44. Having the guide tube 17 is preferable from the viewpoint of preventing the working fluid flow in the EHD pump 1 from diffusing radially outward. It is also effective from the viewpoint of making it easier to attach and detach the EHD pump 1 to the pipe that serves as the flow path for the working fluid. The guide tube 17 is usually insulating so as not to form an electrical passage between the two poles of the EHD pump 1.

[0164] The guide tube 17 has insulating properties to prevent current flow between electrodes in the EHD pump 1, and also possesses physical properties (such as liquid tightness and strength) to guide the working fluid. The material of the guide tube 17 can be appropriately selected from a range that can exhibit these properties. Examples of materials for the guide tube 17 include inorganic and organic materials. Examples of inorganic materials include minerals. Examples of organic materials include resins.

[0165] The size of the guide tube 17 can be appropriately selected according to the external dimensions and fluid delivery capacity of the EHD pump 1. For example, if the internal dimensions of the guide tube 17 are too small or too large, it may become difficult to accommodate the EHD pump 1, and it may also become difficult to achieve the desired flow rate of the working fluid when the EHD pump 1 is operating. From this perspective, the internal dimensions of the guide tube 17 can be appropriately selected, for example, the internal dimensions of the guide tube 17 may be 0.1 mm or more, 1 mm or more, or 10 mm or more. For similar reasons, the internal dimensions of the guide tube 17 may be 100 mm or less, 50 mm or less, or 20 mm or less.

[0166] <Power supply> Furthermore, the EHD pump according to the embodiment of the present invention may further include a power supply that applies a voltage of 1V to 20000V to the first electrode and the second electrode. The power supply can be appropriately selected from known power supplies within a range that allows a voltage capable of achieving the desired fluid delivery performance of the EHD pump to be applied between the two electrodes. From the viewpoint of achieving the desired fluid delivery performance of such an EHD pump, the voltage that the power supply can apply may be 1V or more, or 10V or more. Also, from a similar viewpoint, the voltage that the power supply can apply may be 20000V or less, or 10000V or less. Note that both electrodes of the EHD pump 1 have connection parts 6 and 8, and the power supply is connected to the connection parts 6 and 8 via conductors.

[0167] [Stacked pump] Figure 45 schematically shows an example of the configuration of a stacked electrohydrodynamic pump (stacked EHD pump) according to an embodiment of the present invention, and Figure 46 shows another example. As shown in Figure 45, the stacked EHD pump 300 has two EHD pumps 1 arranged in series inside the guide tube 17 described above. The distance between the two EHD pumps 1 is sufficiently wide compared to the distance between each electrode in the EHD pump 1 (thickness of the support part 2), for example, 0.001 mm or more. Therefore, there is no electrical influence between the first electrode of the lower EHD pump 1 in the figure and the second electrode of the upper EHD pump 1 in the figure. Thus, by applying a voltage of the same sign with the same current direction to each EHD pump 1, the stacked EHD pump 300 pumps the working fluid in the guide tube 17 in one direction.

[0168] Since the stacked EHD pump 300 has multiple EHD pumps 1 in series, it can operate at a higher output than the aforementioned EHD pump 1, and is therefore preferable from the viewpoint of increasing the flow rate of the working fluid.

[0169] Furthermore, the stacked EHD pump 310 shown in Figure 46 consists of three EHD pumps 1 arranged in series. Each of the three EHD pumps 1 is connected via a pump spacer 311. In addition, a pump connection section 312 is connected to the lower side of the bottommost EHD pump 1 in the figure, and to the upper side of the topmost EHD pump 1 in the figure.

[0170] The pump spacer 311 has both fluid permeability and insulating properties. The configuration of the pump spacer 311 can be appropriately set within a range that exhibits fluid permeability to allow working fluid to flow from one EHD pump 1 to the other EHD pump 1, and insulating properties to block electrical influence between one EHD pump 1 and the other EHD pump 1. For example, the pump spacer 311 may be a cylindrical member made of insulating resin that has sufficient rigidity to support the EHD pump 1 and whose edges are in close contact with the peripheral edge of the support portion 2 of the EHD pump 1, or it may be a disc-shaped member having the same configuration as the support portion 2 of the EHD pump 1 except for having an appropriate thickness.

[0171] Furthermore, the pump connection section 312 is a component for connecting the stacked EHD pump 310 to a destination or source of the working fluid, such as a pipe that serves as a flow path for the working fluid. More specifically, the pump connection section 312 can be appropriately selected according to the configuration of the connection destination, within the range of having sufficient fluid permeability for the working fluid and a configuration that allows connection to both the upstream and downstream sides of the stacked EHD pump 310. The pump connection section 312 may have the same configuration as the support section 2 of the EHD pump 1, except for having the connection structure described above, and may have a known connector structure that connects to the EHD pump 1 at one end and allows fluid to pass through at the other end.

[0172] Since the stacked EHD pump 310 has multiple EHD pumps 1 connected via pump spacers 311, electrical interference between adjacent EHD pumps 1 can be prevented even if the distance between them is short. Therefore, the stacked EHD pump 310 is even more suitable than the aforementioned stacked EHD pump 300 from the viewpoint of miniaturization.

[0173] Furthermore, as a method for arranging two or more EHD pumps in series, it is also possible to avoid using the pump spacers described above and instead create grooves around the inner circumferential wall of the guide tube and fit the EHD pumps into these grooves. Adopting such a method is preferable from the standpoint of simplifying the manufacturing process by reducing the number of components and constructing a simple stacked EHD pump. The cross-sectional shape of the guide tube is flexible, but it is preferable that it follows the outer edge of the EHD pump when viewed from above. As for structures for fitting the EHD pump into the grooved guide tube, examples include splitting the guide tube lengthwise or making a part of the guide tube wall a removable lid.

[0174] [Application] The EHD pump 1 and the stacked EHD pumps 300 and 310 according to the embodiment of the present invention are all applicable to the actuator and the stacked actuator EHD pump according to the embodiment of the present invention described above.

[0175] Furthermore, the EHD pump 1 and the stacked EHD pumps 300 and 310 according to the embodiment of the present invention can be used as liquid transfer devices utilizing the EHD effect in pipelines (the usual application of EHD pumps). The actuator according to the embodiment of the present invention can be used in the medical or industrial fields; for example, in the medical field it can be used in prosthetic arms, and in the industrial field it can be used in manipulators in robots.

[0176] Furthermore, the EHD pump of the present invention can be suitably used for the following cooling applications.

[0177] For example, the EHD pump of the present invention can be used for cooling central processing units (CPUs) or graphics processing units (GPUs) installed in personal computers or workstations, for thermal management of electronic equipment in server racks, and for supplying circulating fluid to cooling systems in large-scale data centers. Furthermore, the EHD pump of the present invention can also be applied to cooling power-hungry computing devices or AI processing units. The EHD pump of the present invention provides highly efficient and stable cooling performance in these applications.

[0178] Furthermore, the EHD pump of the present invention can be suitably used for thermal management applications in outer space or underground where air cooling is difficult.

[0179] Furthermore, because the EHD pump of the present invention can be made compact, it can also be used to supply circulating fluid in cooling suits, cooling mats, or cooling beds used by humans. The excellent quietness of the EHD pump of the present invention is also suitable for expanding the range of applications in these uses.

[0180] Furthermore, the operating fluid for the micropump described in Japanese Patent Publication No. 2024-035161 and the pump described in Japanese Patent Publication No. 2024-108020 can also be used for the various applications described above.

[0181] As is clear from the above explanation, the EHD pump and stacked EHD pump in the present invention can achieve higher output and a more compact design compared to conventional EHD pumps. Furthermore, the actuator and stacked actuator in the present invention can achieve higher output and a wider range of operations compared to conventional actuators that utilize the EHD effect, and are also more compact. The present invention, which offers these advantages, is expected to contribute to achieving, for example, Goal 9 of the United Nations Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation."

[0182] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Examples]

[0183] [Example 1] A printed circuit board with a thickness of 0.3 mm was prepared by fabricating electrode layers with a diameter of 10 mm and a thickness of 18 μm on both sides. The shape of the electrode layer included a circular electrode portion with a diameter of 10 mm, as well as a linear connection portion extending radially from there for connecting a conductor. Circular holes with a diameter of 0.6 mm were formed in the electrode portion at intervals of 0.7 mm (with a distance of 0.7 mm between the centers of the holes). Thus, the EHD pump P1 of Example 1 was prepared.

[0184] [Examples 2-5] Two printed circuit boards having electrode layers on both sides were prepared, and a 1 mm thick silicone spacer, having the same planar shape as the printed circuit boards and made by blade casting Ecoflex® 00-30 (Smooth-On), was sandwiched between the two printed circuit boards. Then, in the same manner as in Example 1, circular holes with a diameter of 0.6 mm were formed in the electrode area at 0.7 mm intervals. In this way, the two-layer laminated EHD pump P2 of Example 2 was prepared.

[0185] Furthermore, the three printed circuit boards and the two silicone spacers were stacked alternately, and circular holes with a diameter of 0.6 mm were formed in the electrode portion at 0.7 mm intervals, in the same manner as in Example 1. In this way, the three-layer laminated EHD pump P3 of Example 3 was prepared.

[0186] Furthermore, a four-layer laminated EHD pump P4 of Example 4 was prepared in the same manner as in Example 3, except that the four printed circuit boards and three silicone spacers were stacked alternately.

[0187] Furthermore, a five-layer laminated EHD pump P5 of Example 5 was prepared in the same manner as in Example 3, except that the five printed circuit boards and four silicone spacers were stacked alternately.

[0188] [Examples 6-10] The EHD pump P6 of Example 6 was prepared in the same manner as in Example 1, except that a printed circuit board with a thickness of 0.15 mm was used instead of a printed circuit board with a thickness of 0.3 mm.

[0189] Furthermore, in the same manner as in Examples 2 to 5, except for using a 0.15 mm thick printed circuit board instead of a 0.3 mm thick printed circuit board, we prepared a two-layer EHD pump P7 in Example 7, a three-layer EHD pump P8 in Example 8, a four-layer EHD pump P9 in Example 9, and a five-layer EHD pump P10 in Example 10.

[0190] [Examples 11-14] The EHD pump P11 of Example 11 was prepared in the same manner as in Example 1, except that a 0.05 mm thick printed circuit board with a 9 μm thick electrode layer was used instead of a 0.3 mm thick printed circuit board with an 18 μm thick electrode layer.

[0191] Furthermore, in the same manner as in Examples 2 to 5, a two-layer laminated EHD pump P12 of Example 12, a three-layer laminated EHD pump P13 of Example 13, and a four-layer laminated EHD pump P14 of Example 14 were prepared, respectively, except that a 0.05 mm thick printed circuit board with a 9 μm thick electrode layer was used instead of a 0.3 mm thick printed circuit board with an 18 μm thick electrode layer.

[0192] [Examples 15, 16] Except for changing the shape of the through-hole opening formed in the electrode layer from a circle to an equilateral triangle, the EHD pump P15 of Example 15 and the EHD pump P16 of Example 16 were prepared in the same manner as in Examples 11 and 12. The diameter of the equilateral triangular through-hole was determined to have the same area as a circle with a diameter of 0.6 mm, and expressed as the distance from one vertex angle to the opposite side, it is 0.7 mm.

[0193] [Performance Test] [Preparation of test specimens] Figure 47 schematically shows the configuration of a test specimen for testing the performance of the EHD pump in the embodiment. AWG28 copper wires 91, 91 were soldered to each of the connection parts on both sides of the EHD pump P1. Next, a connector 92 was prepared using a stereolithography 3D printer (Form3, Formlabs) made of clear resin. The connector 92 has, for example, a joint on one main surface that abuts the EHD pump and a joint on the other main surface that fits into the working fluid tube, and a through hole that serves as a flow path for the working fluid from one main surface to the tip of the joint. The EHD pump P1 was sandwiched between the pair of connectors 92, 92, and the connector and the EHD pump P1 were fixed together with screws 93, 93 at positions facing each other across the center of the planar shape. If there was a gap at the joint between the connector and the EHD pump P1, TSE387 (Momentive Performance Materials), a silicone adhesive sealant, was applied to the gap and left to dry completely to seal the gap.

[0194] Thus, a test specimen S1 was prepared in which the EHD pump P1 of Example 1 could be connected to the flow path of the working fluid.

[0195] [Preparing the test setup] Figure 48 schematically shows the configuration of a test setup for testing the performance of the EHD pumps P1 to P15 of the embodiment. As shown in Figure 48, the test setup consists of a reservoir 901 containing the working fluid, a flow sensor 902 (FD-X series, Keyence), a pressure sensor 903 (ADP5130, Panasonic), and a clamp 904, all connected in series and in a ring by a silicone tube 905 with an inner diameter of 10 mm and an outer diameter of 13 mm. The test specimen S is connected to the silicone tube 905 so as to be interposed between the reservoir 901 and the flow sensor 902. The test specimen S is connected to a power supply (not shown) via copper wires 91, 91.

[0196] The pressure sensor 903 is connected to a branch pipe (not shown) from the silicone tube 905 and measures the air pressure inside the branch pipe. The clamp 904 is configured to crush the silicone tube 905 by tightening two flat plates with screws, thereby blocking the flow path of the working fluid. The clamp 904 was fabricated using clear resin with a stereolithography 3D printer (Form3, Formlabs).

[0197] By slightly lifting and tilting reservoir 901, which contains the working fluid, the pressure difference allows the working fluid to fill the entire test setup. The working fluid used was a liquid prepared by adding 0.2% by mass of polyvinyl chloride (PVC, TK-500 manufactured by Shin-Etsu Chemical Co., Ltd. (average degree of polymerization 520), number average molecular weight 32500) to dibutyl adipate (DBA).

[0198] In the test specimen S, an amplifier power supply module (HOPP-10P(A), Matsusada Precision) was used to power the EHD pump, and the power supply to the EHD pump was controlled by a 4-channel power supply (PMX32-2QU, Kikusui Electronics). The voltage applied to the EHD pump was measured using the voltage monitor terminal of the 4-channel power supply, and the current flowing through the EHD pump was measured using a clamp-type low-current sensor (HDCC-3mA-D1, Picsor). These values ​​were then read using a multimeter (Model 2100, Keithley Instruments). The 4-channel power supply and the multimeter communicated with a PC using the VISA standard, and power control and data reading were performed by program. All measurements were taken at a frequency of 100Hz.

[0199] [Method for measuring flow rate] The clamp 904 is removed, and the EHD pump is operated with the working fluid filling the test setup's passage. The flow rate of the working fluid circulating through the passage is measured by the flow sensor 902. The current output from the flow sensor 902 according to the flow rate is read using a multimeter (Model 2100, Keithley Instruments). This multimeter also communicates with the PC using the VISA standard, and the data is read by a program to determine the flow rate.

[0200] The specific procedure for measuring the flow rate is as follows: First, fill reservoir 901 and the flow path with working fluid and remove any air bubbles. Next, connect the power supply to the EHD pump and start the program. After a 5-second offset, a high voltage is applied for 10 seconds. After the voltage application is complete, wait for 5 seconds, and the measurement is finished.

[0201] [Method for measuring pressure] When the working fluid is flowed with the silicone tube 905 (the fluid passage) blocked by clamp 904, the air accumulated at the tip of the aforementioned branch pipe is pushed by the fluid level, and this pressure is measured by the pressure sensor 903. The voltage output from the pressure sensor 903 according to the pressure is read using a multimeter (Model 2100, Keithley Instruments). This multimeter also communicates with the PC using the VISA standard, and the data is read by a program to determine the pressure value.

[0202] The specific procedure for measuring pressure is as follows: First, fill the reservoir 901 and the flow path with working fluid and remove any air bubbles. Next, close the silicone tube 905 with clamp 904 and confirm that the flow rate is 0 using the flow sensor 902. Then, connect the power supply to the EHD pump and activate the program. After a 5-second offset, a high voltage is applied for 20 seconds. After the voltage application is complete, wait for 5 seconds and the measurement is finished.

[0203] [Performance Test Results 1-1] Test specimen S1 was mounted in the test setup, and a liquid containing 0.2% by mass of polyvinyl chloride (PVC) added to dibutyl adipate (DBA) was used as the working fluid. This fluid was supplied to the EHD pump of test specimen S at 23°C, and the fluid was pumped under a voltage of 1kV to 5kV. The flow rate and pressure were measured. The results are shown in Table 1. Note that the applied voltage in the table also includes the voltage value per unit distance between the pair of electrode layers.

[0204] [Table 1]

[0205] [Performance Test Results 1-2] Except for changing the fluid to Noah7100 (3M; methyl perfluoroisobutyl ether), the flow rate and pressure in test specimen S1 were measured in the same manner as in performance test result 1-1 when a voltage of 1 to 5 kV was applied. The results are shown in Table 2.

[0206] [Table 2]

[0207] [Performance test results 2-5] The flow rate and pressure in each of the test specimens S2 to S5 were measured when a voltage of 1 to 5 kV was applied, in the same manner as in performance test result 1-1, except that test specimen S1 was replaced with test specimens S2 to S5. The results are shown in Table 3. Note that "Measurement not possible" in Table 3 indicates that test specimen S5 failed due to internal discharge when 5 kV was applied.

[0208] [Table 3]

[0209] [Performance test results 6-10] The flow rate and pressure in each of the test specimens S6 to S10 were measured when a voltage of 1 to 5 kV was applied, in the same manner as in performance test result 1-1, except that test specimen S1 was replaced with test specimens S6 to S10. The results are shown in Table 4.

[0210] [Table 4]

[0211] [Performance test results 11-14] Except for replacing test specimen S1 with test specimens S11 to S14 and changing the voltage applied to the EHD pump from 1 to 5 kV to 0.17 to 1.5 kV, the flow rate and pressure were measured for each of the test specimens S11 to S14 in the same manner as in performance test result 1-1. The results are shown in Table 5.

[0212] [Table 5]

[0213] In Table 5, "Measurement not possible" when the applied voltage is 0.17kV indicates that the measured value fell below the detection limit of the flow sensor or pressure sensor. Furthermore, "Measurement not possible" when the applied voltage is 1.0kV or 1.5kV indicates that the working fluid underwent dielectric breakdown because the applied voltage exceeded the working fluid's dielectric strength (dielectric strength).

[0214] [Performance test results 15, 16] Except for changing test specimen S11 to test specimen S15 and test specimen S12 to test specimen S16, and changing the voltage applied to the EHD pump from 0.17~1.5kV to 0.17~0.83kV, the flow rate and pressure were measured for test specimens S15 and S16 in the same manner as performance test results 11 and 12. The results are shown in Table 6. For comparison, the performance test results for test specimens S11 and S12 are also shown in Table 6. In Table 6, "Not Measurable" when the applied voltage is 0.17kV indicates that the measured value fell below the detection limit of the flow sensor or pressure sensor.

[0215] [Table 6]

[0216] [Consideration] As is clear from Tables 1 and 2, the EHD pump of this embodiment exhibits higher output as the voltage applied to the electrode layer increases. Furthermore, as is clear from Tables 3 to 5, the stacked EHD pump of this embodiment exhibits higher output as the number of stacked EHD pumps increases.

[0217] Furthermore, as is clear from Tables 3 and 4, within the range where the EHD effect is obtained, the output of the EHD pump tends to decrease as the distance between the electrode layers in the EHD pump decreases. This is thought to be due to the distance between the electrode layers.

[0218] Furthermore, as is clear from Tables 4 and 5, when the distance between electrode layers in an EHD pump is short, the increase in EHD pump output when the number of stacked EHD pumps increases tends to decrease. This is thought to be due to the distance between electrode layers. Also, as is clear from Table 5, this tendency is more pronounced when the electrode layer in the EHD pump is thin. This, too, is thought to be due to the distance between electrode layers.

[0219] Furthermore, as is clear from Table 6, triangular through-holes in EHD pumps produce higher output than circular through-holes. This is thought to be because a longer perimeter of the through-hole relative to its opening area in the electrode layer results in higher output. [Explanation of Symbols]

[0220] 1, 13, 53, 63, 131-134, 731, 732, 831-834, P1 Electrohydrodynamic (EHD) pump 2 Support part 3, 13A first electrode 4, 13B Second electrode 5, 7 Flow channel section 6, 8 Connection part 9 holes 10, 20, 30, 40, 50, 60, 70, 400, 701, 702 Actuators 11, 21, 31, 41, 51, 61A, 61B, 61C, 61D, 71, 81 Liquid chambers 12 Sealing material 13C, 53C, 63C Spacers 13D Rod part 13E Partition plate 14, 24, 34, 44, 54, 64A, 64B, 64C, 64D, 74A, 74B, 84A, 84B First chambers 15, 25, 35, 45, 55, 65A, 65B, 65C, 65D, 75A, 75B, 8 Second chambers 16, 26, 443, 841A, 841B Sponge members 17 Guide tube 31A, 31B Operating parts 86, 111 Top plate parts 91 Copper wire 92 Connector 93 Screw 100, 110, 120, 200, 210 Stacked actuators 300, 310 Stacked (EHD) pumps 311 Spacer for pump 312 Pump connection part 441 First side wall part 442 Second side wall part 451 First frame part 452 Second frame part 453 Third side wall part 454 Fourth side wall part 541, 741 First covering parts 551, 751 Second covering parts 601 - 604 Joint parts 641 Inner tube 651 Outer tube 851 Covering part 901 Reservoir 902 Flow sensor 903 Pressure sensor 904 Clamp 905 Silicone tube S1 Specimen

Claims

1. A liquid chamber filled with an insulating working fluid, The system includes an electrohydrodynamic pump that divides the liquid chamber into a first chamber and a second chamber and circulates the working fluid between the first chamber and the second chamber, The first chamber and the second chamber are configured to be deformable according to the amount of working fluid contained within them, and the operating part further includes an operating part that operates in a size corresponding to the amount of deformation of at least one of the first chamber and the second chamber as a result of the deformation caused by the amount of working fluid. Actuator.

2. The electrohydrodynamic pump is slidable within the liquid chamber, The actuator according to claim 1, wherein the operating part is a member connected to the electrohydrodynamic pump and extending outside the liquid chamber.

3. One or both of the first chamber and the second chamber include a deformable wall portion in at least part thereof, and deforms in accordance with the amount of working fluid contained within the chamber. The actuator according to claim 1, wherein the operating part is the deformable part of the liquid chamber.

4. The actuator according to claim 3, wherein both the first chamber and the second chamber are configured to be deformable according to the amount of working fluid contained in the chamber.

5. The actuator according to claim 4, wherein the electrohydrodynamic pump is flexible.

6. The device comprises a deformable first tube, a tubular electrohydrodynamic pump, and a deformable second tube, arranged in this order from the inside of the tube. The actuator according to claim 4, wherein at two or more joining points in the circumferential direction of the tubular electrohydrodynamic pump in the cross-section of the pipe, the first pipe is joined to the inner circumferential surface of the tubular electrohydrodynamic pump to form the first chamber, and the second pipe is joined to the outer circumferential surface of the tubular electrohydrodynamic pump to form the second chamber.

7. One of the first chamber and the second chamber is configured to be deformable according to the amount of working fluid contained in the chamber. The other of the first chamber and the second chamber is configured to maintain a specific shape regardless of the amount of working fluid contained within the chamber. The actuator according to claim 3.

8. The liquid chamber has two or more of the first chambers relative to one of the second chambers, The actuator according to claim 7, wherein the electrohydrodynamic pump separates at least one of the two or more first chambers from the second chamber.

9. The actuator according to claim 1, wherein one or both of the first chamber and the second chamber include a sponge member having liquid permeability and elasticity.

10. The actuator according to claim 1, wherein the working fluid contains a low molecular weight component with a molecular weight of 1,000 or less and a high molecular weight compound with a number average molecular weight of 10,000 or more.

11. A stacked actuator comprising two or more actuators according to any one of claims 1 to 10 stacked on top of each other.

12. An electrohydrodynamic pump having a first electrode with a hole through which liquid flows, and a second electrode having a hole through which liquid flows and positioned opposite the first electrode, The thickness of the first electrode and the second electrode is 0.2 mm or less, The device further includes an insulating spacer interposed between the first electrode and the second electrode to prevent the first electrode and the second electrode from approaching each other when a voltage is applied. Electrohydrodynamic pump.

13. The electrohydrodynamic pump according to claim 12, wherein the spacer has a hole that connects the hole of the first electrode and the hole of the second electrode.

14. The electrohydrodynamic pump according to claim 13, wherein the hole in the first electrode, the hole in the second electrode, and the hole in the spacer all have the same size and the same opening shape.

15. The electrohydrodynamic pump according to claim 12, wherein the hole in at least one of the first electrode and the second electrode has an opening shape that includes a circular hole.

16. The electrohydrodynamic pump according to claim 12, wherein the hole in at least one of the first electrode and the second electrode has an opening shape in which a curved portion and a straight portion are connected.

17. The electrohydrodynamic pump according to claim 12, wherein the hole having at least one of the first electrode and the second electrode has a polygonal opening shape.

18. The electrohydrodynamic pump according to claim 12, further comprising an insulating guide tube circumferentially provided to the electrohydrodynamic pump and extending along the opposing directions of the first electrode and the second electrode.

19. The electrohydrodynamic pump according to claim 18, wherein the material of the guide tube is either an inorganic material or an organic material or both.

20. The electrohydrodynamic pump according to claim 19, wherein the inorganic material includes a mineral and the organic material includes a resin.

21. The electrohydrodynamic pump according to claim 18, wherein the inner dimensions of the guide tube are 0.1 mm or more and 100 mm or less.

22. The electrohydrodynamic pump according to claim 12, further comprising a power supply for applying a voltage of 1V to 20,000V to the first electrode and the second electrode.

23. A stacked pump comprising two or more electrohydrodynamic pumps according to any one of claims 12 to 22, arranged in series.

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