Electrostatic actuator structure

Abstract

An electrostatic actuator structure according to one aspect of the present disclosure includes a pump unit, an output unit and a passage unit. The inside of the pump unit is filled with a dielectric liquid 9. The output unit is deformed by an internal pressure change. The passage unit allows the inside of the pump unit and the inside of the output unit to communicate with each other. The output unit has welded parts which are arranged in a first direction and in each of which a first member constituting an upper surface and a second member constituting a lower surface are welded at peripheral edges of the first member and the second member. In the welded part, the welding width in at least a part of a pair of sides arranged in the first direction is larger than the welding width in a pair of sides arranged in a second direction orthogonal to the first direction.

Description

Electrostatic Actuator Structure

[0001] This application claims priority to Japanese Patent Application No. 2024-146548, filed on August 28, 2024, the contents of which are incorporated herein by reference.

[0002] Electrostatic actuators are known that use electrostatic attractive force generated between two electrodes as a driving force.

[0003] As such electrostatic actuators, HASEL (hydraulically amplified self-healing electrostatic) actuators have recently been attracting attention. HASEL actuators have a structure in which a pair of electrodes are provided on both ends of a shell filled with a dielectric liquid. When a voltage is applied to the pair of electrodes, the dielectric liquid inside the shell is polarized, generating an electrostatic attraction between the electrodes. This attracts the pair of electrodes, causing the dielectric liquid inside the shell to move and the shell to deform. HASEL actuators can use this shell deformation to push or pull up objects, for example. HASEL actuators are a type of artificial muscle, and are expected to be used in soft robots.

[0004] Patent Document 1 discloses a separate-type electrostatic actuator in which a shell is composed of a pump section provided with a pair of electrodes, a bag-shaped output section that is deformed by a dielectric liquid discharged from the pump section, and a connecting tube that connects the pump section and the output section.

[0005] US Patent Application Publication No. 2024 / 0068451

[0006] The above-mentioned conventional technology has room for further improvement in terms of increasing the directivity of the direction in which the output section deforms.

[0007] The present disclosure provides a technique that can increase the directivity of the direction in which the output section deforms.

[0008] An electrostatic actuator structure according to one aspect of the present disclosure includes a sheet-like base portion and a plurality of electrostatic actuators provided on the base portion. The electrostatic actuators have a first surface and a second surface opposite the first surface. The electrostatic actuators include a pump portion, a dielectric liquid, a first electrode, a second electrode, an output portion, and a passage portion. The pump portion is flexible. The dielectric liquid is located inside the pump portion. The first electrode is located on the first surface. The second electrode is located on the second surface. The output portion is located at a position away from the pump portion and changes shape in response to changes in internal pressure. The passage portion communicates the interior of the pump portion with the interior of the output portion. The plurality of output portions are aligned in a first direction, which is an in-plane direction of the base portion. The output portion has a pair of first sides aligned in the first direction and a pair of second sides aligned in a second direction, which is in-plane and perpendicular to the first direction. The pair of first sides and the pair of second sides are welded to the base portion. When the width of the welding of the pair of first sides and the pair of second sides in the direction from the inside to the outside of the output section is defined as the welding width, at least a portion of the first sides has a welding width expansion portion where the welding width is wider than the welding width of the second sides.

[0009] According to the present disclosure, it is possible to increase the directivity of the direction in which the output section deforms.

[0010] FIG. 1 is an explanatory diagram showing an electric actuator structure according to a first embodiment. FIG. 2 is an explanatory diagram of the electric actuator according to the first embodiment in a plan view. FIG. 3 is an explanatory diagram of the electric actuator according to the first embodiment in a side view. FIG. 4 is an explanatory diagram of the operating principle of a HASEL. FIG. 5 is an explanatory diagram of the operating principle of a HASEL. FIG. 6 is an explanatory diagram of the operating principle of a HASEL. FIG. 7 is an explanatory diagram showing the electric actuator structure in a contracted state according to the first embodiment. FIG. 8 is an explanatory diagram of the output section according to the first embodiment in a plan view. FIG. 9 is an explanatory diagram of the output section according to the second embodiment in a plan view. FIG. 10 is an explanatory diagram of the output section according to the third embodiment in a plan view. FIG. 11 is an explanatory diagram of the electric actuator according to the fourth embodiment in a plan view. FIG. 12 is an explanatory diagram of the electric actuator according to the fourth embodiment as seen from a second direction. FIG. 13 is an explanatory diagram of the electric actuator according to the fifth embodiment in a plan view. FIG. 14 is an explanatory diagram of the electric actuator structure according to the second embodiment in a plan view. FIG. 15 is a cross-sectional explanatory diagram of the electric actuator structure taken along line CC shown in FIG. 14. Fig. 16 is an explanatory diagram showing an enlarged view of the area enclosed by the dashed line in Fig. 15. Fig. 17 is an explanatory diagram of a pump section according to a sixth embodiment. Fig. 18 is an explanatory diagram of a pump section according to a seventh embodiment.

[0011] Hereinafter, an embodiment of an electric actuator structure will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment described below. In the following description, components that perform the same functions are assigned the same reference numerals, and redundant description will be omitted.

[0012] Fig. 1 is an explanatory diagram showing an electric actuator structure 2 according to a first embodiment. Fig. 2 is an explanatory diagram showing a plan view of an electric actuator 3 according to the first embodiment. Fig. 3 is an explanatory diagram showing a side view of the electric actuator 3 according to the first embodiment.

[0013] 1, the electric actuator structure 2 includes a plurality of electric actuators 3. The plurality of electric actuators 3 are connected to each other and arranged side by side in a first direction A within a plane. The electric actuators 3 are HASEL (Hydraulically Amplified Self-healing Electrostatic) actuators.

[0014] 2 , each electric actuator 3 includes a pump section 4, an output section 5, and a passage section 6. The pump section 4, the output section 5, and the passage section 6 are each a bag-like shell formed integrally by welding a flexible film that forms the upper surface and a flexible film that forms the lower surface at their peripheries. The multiple output sections 5 are arranged side by side in the first direction A.

[0015] 3, the pump section 4 has a first surface 4A and a second surface 4B located on the opposite side of the first surface 4A. The films constituting the first surface 4A and the second surface 4B are flexible. In other words, the pump section 4 is a flexible bag.

[0016] The pump section 4 is filled with a dielectric liquid. That is, the dielectric liquid is located inside the pump section 4. The pump section 4 also includes a first electrode 7 and a second electrode 8. The first electrode 7 is located on a first surface 4A of the pump section 4. Specifically, the first electrode 7 is disposed in contact with the first surface 4A so as to cover the first surface 4A. The second electrode 8 is located on a second surface 4B of the pump section 4. Specifically, the second electrode 8 is disposed in contact with the second surface 4B so as to cover the second surface 4B.

[0017] The output section 5 is provided at a position away from the pump section 4. The output section 5 is a flexible bag body similar to the pump section 4. The shape of the output section 5 changes depending on changes in the internal pressure. Specifically, the output section 5 expands when the internal pressure increases, and contracts when the internal pressure decreases. The passage section 6 connects the inside of the pump section 4 with the inside of the output section 5.

[0018] When a voltage is applied between the first electrode 7 and the second electrode 8 of the electric actuator 3, the first electrode 7 and the second electrode 8 are attracted to each other. As a result, the dielectric liquid inside the pump section 4 is pushed out from the pump section 4 through the passage section 6 to the output section 5, as shown by the white arrow in FIG. 2 .

[0019] As a result, the output section 5 is deformed and expanded due to an increase in internal pressure caused by the inflow of the dielectric liquid. The operating principle of the HASEL will now be described with reference to Figures 4 to 6. Figures 4 to 6 are explanatory diagrams of the operating principle of the HASEL.

[0020] It should be noted that, among the components of the HASEL shown in Figures 4 to 6, parts that perform the same functions as the components of the electric actuator 3 according to the first embodiment are given the same reference numerals as those shown in Figure 3, and redundant explanations will be omitted.

[0021] As shown in Fig. 4, the device includes a pump section 4 and an output section 5. The pump section 4 is a flexible shell filled with a dielectric liquid 9. A first electrode 7 is provided on one surface of the pump section 4, and a second electrode 8 is provided on the other surface opposite to the first surface.

[0022] The pump section 4 is configured so that when no voltage is applied between the first electrode 7 and the second electrode 8, the width narrows from the end opposite to the output section 5 toward the end farther from the output section 5.

[0023] In such a HASEL, when a voltage is applied between the first electrode 7 and the second electrode 8, the dielectric liquid 9 is polarized, generating an electrostatic attraction between the first electrode 7 and the second electrode 8. This attracts the first electrode 7 and the second electrode 8, causing the dielectric liquid 9 in the pump section 4 to move and the output section 5 to deform.

[0024] Specifically, as shown in Fig. 5, the first electrode 7 and the second electrode 8 are attracted to each other in order from the part where the gap between them is smallest to the part where the gap between them is largest, as shown in Fig. 6, and finally the first electrode 7 and the second electrode 8 are attracted to the part where the gap between them is largest, and the dielectric liquid 9 is pushed out to the output section 5.

[0025] As a result, the output unit 5 becomes larger in width and smaller in length as a result of the dielectric liquid 9 being poured into it, compared to before the dielectric liquid 9 was poured in. By utilizing this deformation of the output unit 5, the HASEL can, for example, push or pull up an object.

[0026] For this reason, HASEL is expected to be used as an artificial muscle. The electric actuator structure 2 is configured to expand and contract in a first direction A (see FIG. 1 ) by utilizing the deformation of the output section 5 of this HASEL.

[0027] 7 is an explanatory diagram showing the electric actuator structure 2 in a contracted state according to the first embodiment. In the electric actuator structure 2, when the dielectric liquid 9 has not flowed into the output section 5, the output section 5 is in a thin and flat state (see FIG. 1).

[0028] When a voltage is applied between the first electrode 7 and the second electrode 8 from this state and the dielectric liquid 9 flows into the output section 5, the electric actuator structure 2 expands so that the output section 5 becomes, for example, cylindrical, as shown in Fig. 7. As a result, the dimension of the output section 5 in the first direction A of the electric actuator structure 2 is reduced, and the length in the first direction A becomes shorter.

[0029] Thereafter, when the voltage is no longer applied between the first electrode 7 and the second electrode 8, the dielectric liquid 9 moves from the output unit 5 to the pump unit 4, causing the output unit 5 to contract and increase in length in the first direction A (returning to its original length). When the electric actuator structure 2 is used, for example, as an artificial muscle that deforms in the first direction A, it is desirable that the directionality of deformation in the first direction A is high.

[0030] For this reason, the electric actuator 3 according to the first embodiment has an output unit 5 configured to increase the directionality of deformation in the first direction A. Fig. 8 is an explanatory plan view of the output unit 5 according to the first embodiment. Fig. 9 is an explanatory plan view of the output unit 5 according to the second embodiment. For convenience, the following description will be given assuming that one direction normal to a plane including the first direction A is up and the other direction is down.

[0031] The output section 5 in the first embodiment includes a first member that forms the upper surface, a second member that forms the lower surface, and a welded portion where the first member and the second member are welded to each other at the peripheral portions of the first member and the second member.

[0032] 8 , the welded portion according to the first embodiment includes a pair of first sides 10 aligned in a first direction A and a pair of second sides 11 aligned in a second direction B that is perpendicular to the first direction A within a plane including the first direction A. The welded portion according to the first embodiment includes a wide portion 10A in which the weld width D1 in at least a part of the first sides 10 is larger than the weld width in the second sides 11.

[0033] As a result, when dielectric liquid 9 flows into the output section 5 according to the first embodiment, the rigidity of the wide portion 10A becomes higher than that of the other portions of the welded portion, making it difficult for the output section 5 to expand in the first direction A and easy for the output section 5 to expand in the normal direction to a plane including the first direction A. Therefore, when dielectric liquid 9 flows into the output section 5 according to the first embodiment, the amount of deformation in the direction of the outline arrow in Fig. 8 increases, resulting in a high directionality of deformation in the first direction A.

[0034] 9, the second side 11 of the output section 5 according to the second embodiment is curved convexly in a direction from the inside to the outside of the output section 5. As a result, the second side 11 of the output section 5 according to the second embodiment is more likely to deform up to the dashed line portion when expanding in the normal direction to the plane including the first direction A than when the second side 11 is not curved (straight). This makes it easier to expand in the normal direction to the plane including the first direction A. Therefore, when the dielectric liquid 9 is flowed into the output section 5 according to the second embodiment, the amount of deformation in the direction of the white arrow in FIG. 9 increases, and the directionality of deformation in the first direction A becomes higher.

[0035] In addition, when the directivity of deformation in the second direction B is to be increased, the output section 5 may be configured as shown in Fig. 10. Fig. 10 is an explanatory plan view of the output section 5 according to the third embodiment. As shown in Fig. 10, the welded portion of the output section 5 according to the third embodiment includes a wide portion 11A in which the weld width D2 in at least a part of the second side 11 is larger than the weld width in the first side 10.

[0036] As a result, when dielectric liquid 9 flows into the output section 5 according to the third embodiment, the rigidity of the wide portion 11A becomes higher than that of the other portions of the welded portion, making it difficult for the output section 5 to expand in the second direction B and easy for the output section 5 to expand in the normal direction to the plane including the first direction A. Therefore, when dielectric liquid 9 flows into the output section 5 according to the third embodiment, the amount of deformation in the direction of the white arrow in Fig. 10 increases, and as a result, the directionality of deformation in the second direction B becomes higher.

[0037] It is also desirable that the pump section 4 of the electric actuator 3 be able to discharge the dielectric liquid 9 with a small applied voltage. For this reason, the electric actuator 3 may be configured, for example, as shown in Figures 11 and 12 .

[0038] Fig. 11 is an explanatory plan view of the electric actuator 3 according to the fourth embodiment. Fig. 12 is an explanatory view of the electric actuator 3 according to the fourth embodiment as viewed from a second direction B. As shown in Figs. 11 and 12 , the first electrode 7 according to the fourth embodiment includes a first individual electrode 71 and a second individual electrode 72. The second electrode 8 according to the fourth embodiment includes a third individual electrode 81 and a fourth individual electrode 82.

[0039] The first individual electrode 71 is arranged on one side of the first surface 4A (see Figure 3) in a direction (first direction A) perpendicular to the arrangement direction (second direction B) of the pump section 4, output section 5 and passage section 6 in a plane including the first direction A.

[0040] The second individual electrode 72 is disposed on the other side of the first surface 4A (see FIG. 3 ) in a direction (first direction A) perpendicular to the arrangement direction (second direction B) of the pump section 4, the output section 5, and the passage section 6 in a plane including the first direction A. The third individual electrode 81 is disposed opposite the first individual electrode 71 with the pump section 4 interposed therebetween. The fourth individual electrode 82 is disposed opposite the second individual electrode 72 with the pump section 4 interposed therebetween.

[0041] The first individual electrode 71 and the third individual electrode 81 are arranged such that the distance between them decreases from the center of the pump unit 4 in the first direction A toward the ends of the pump unit 4 in the first direction A. Furthermore, the second individual electrode 72 and the fourth individual electrode 82 are arranged such that the distance between them decreases from the center of the pump unit 4 in the first direction A toward the ends of the pump unit 4 in the first direction A.

[0042] As a result, when a voltage is applied between the first individual electrode 71 and the third individual electrode 81 and between the second individual electrode 72 and the fourth individual electrode 82, the pump section 4 of the fourth embodiment also moves the dielectric liquid 9 in the direction indicated by the white arrow in FIG. 11 .

[0043] That is, the pump section 4 according to the fourth embodiment does not simply push the dielectric liquid 9 in the direction of the output section 5, but pushes the dielectric liquid 9 from both ends of the pump section 4 in the first direction A towards the center in the first direction A, while pushing it in the direction of the output section 5. This enables the pump section 4 according to the fourth embodiment to improve the discharge capacity of the dielectric liquid 9.

[0044] More specifically, when a voltage is applied between the first individual electrode 71 and the third individual electrode 81 and between the second individual electrode 72 and the fourth individual electrode 82, the electrodes close from the end side in the first direction A where the gap is small. Then, as the distance between the electrodes in the vicinity of the closed portion becomes smaller, the electrodes close in a chain reaction from the end side toward the center. This allows the pump unit 4 to operate with an applied voltage sufficient to close the electrodes at the end side in the first direction A.

[0045] Furthermore, in order to further improve the discharge capacity of the dielectric liquid 9, the electric actuator 3 may be configured as shown in Fig. 13. Fig. 13 is an explanatory plan view of an electric actuator 3 according to a fifth embodiment.

[0046] As shown in Figure 13, the pump section 4 of the electric actuator 3 according to the fifth embodiment is configured so that the distance H between the first electrode 7 and the second electrode 8 increases from the second end of the pump section 4, which is farther from the output section 5, to the first end, which is closer to the output section 5.

[0047] The first end is, specifically, the end closest to the passage portion 6 of both ends of the pump portion 4 in the arrangement direction (second direction) of the output portion 5 and the passage portion 6. The second end is, specifically, the end farthest from the passage portion 6 of both ends of the pump portion 4 in the arrangement direction (second direction) of the output portion 5 and the passage portion 6.

[0048] The distance H between the first electrode 7 and the second electrode 8 increases from the second end to the first end, which allows the pump unit 4 of the fifth embodiment to improve the discharge capacity of the dielectric liquid 9 compared to when the distance H between the first electrode 7 and the second electrode 8 is uniform throughout the second direction, as in the fourth embodiment.

[0049] In addition, the pump section 4 of the electric actuator 3 in the fifth embodiment is configured so that the flow path width W of the dielectric liquid 9 increases as it moves from the second end of the pump section 4, which is far from the output section 5, to the first end, which is close to the output section 5.

[0050] That is, in the pump section 4 according to the fifth embodiment, the flow path width W, which is the dimension of the pump section 4 in a plane perpendicular to the arrangement direction (second direction) of the output section 5 and the passage section 6, increases from the second end to the first end. As a result, the pump section 4 according to the fifth embodiment can improve the discharge capacity of the dielectric liquid 9 compared to a case in which the flow path width W in the second direction is uniform.

[0051] Next, an electric actuator structure 20 according to a second embodiment will be described with reference to Figures 14 to 18. Figure 14 is an explanatory plan view of the electric actuator structure 20 according to the second embodiment. Figure 15 is an explanatory side view of the electric actuator structure 20 according to the second embodiment. Figure 16 is an enlarged explanatory view of the area enclosed by the dashed line in Figure 15. Figure 17 is an explanatory view of a first pump section 32A according to a sixth embodiment. Figure 18 is an explanatory view of a first pump section 32A according to a seventh embodiment.

[0052] As an example of a HASEL, for example, U.S. Patent No. 10,995,779 discloses an electrostatic actuator that uses deformation of a shell in a HASEL to lift an object suspended from a wire. However, the HASEL described in U.S. Patent No. 10,995,779 has room for further improvement in terms of providing an electrostatic actuator that is more suitable for the operation of lifting an object.

[0053] Therefore, the electric actuator structure 20 according to the second embodiment has a configuration that is more suitable for the operation of lifting an object. As shown in Fig. 13, the electric actuator structure 20 includes a flexible shell 30, a dielectric liquid located inside the shell 30, a plurality of electrodes 40, and string members 50. Wires 43 are connected to the electrodes 40.

[0054] The shell 30 includes an output section 31, a first pump section 32A, and a second pump section 32B. The output section 31, the first pump section 32A, and the second pump section 32B are each a bag-shaped member integrally formed by welding a flexible film that forms the upper surface and a flexible film that forms the lower surface at their peripheries.

[0055] The interior of the shell 30 is filled with a dielectric liquid. The multiple output sections 31 are arranged at intervals along a first direction A. The first pump section 32A and the second pump section 32B are arranged in a second direction B that is perpendicular to the first direction A relative to the multiple output sections 31. At least two of the multiple electrodes 40 are arranged opposite each other with the first pump section 32A and the second pump section 32B interposed therebetween.

[0056] When a direction perpendicular to the first direction A and the second direction B is defined as a third direction, the string member 50 has a first portion 51 located on one side of the output portion 31 in the third direction and a second portion 52 located on the other side of the output portion 31 in the third direction (see FIGS. 15 and 16 ). The first portion 51 and the second portion 52 are stretched across the multiple output portions 31 alternately along the first direction A.

[0057] Furthermore, the first pump portion 32A is disposed on one side of the plurality of output portions 31 in the second direction B. The second pump portion 32B is disposed on the other side of the plurality of output portions 31 in the second direction B. The electrode 40 includes a pair of first electrodes 40A and 40B (see FIGS. 17 and 18 ) disposed opposite each other with the first pump portion 32A interposed therebetween.

[0058] The electrode 40 also includes a pair of first electrodes and a pair of second electrodes arranged opposite each other with the second pump section 32B interposed therebetween. Note that the configuration of the first electrode and the second electrode arranged opposite each other with the second pump section 32B interposed therebetween is similar to the configuration of the second electrode 40A and the second electrode 40B arranged opposite each other with the first pump section 32A interposed therebetween, and therefore is not shown in the drawings.

[0059] The electric actuator structure 20 also includes a frame body 60 that is rectangular in plan view and surrounds the shell 30. The frame body 60 includes two first sides 61 located on one side and the other side of the shell 30 in the first direction A, and two second sides 62 located on one side and the other side of the shell 30 in the second direction B.

[0060] The string member 50 has one end fixed to one 61A of the two first sides 61. When viewed from the end fixed to one 61A of the two first sides 61 as the starting point, the string member 50 is stretched across the multiple output parts 31 such that the first portions 51 and the second portions 52 are alternately repeated along the first direction A.

[0061] The string member 50 is then folded back so as to straddle the other 61B of the two first sides 61, and is again stretched across the multiple output sections 31 so that the first section 51 and the second section 52 are alternately repeated along the first direction A.

[0062] Here, the section of the string member 50 from one end to the point where it is folded back at the other 61B of the two first sides 61 is referred to as the outgoing section, and the section after it is folded back at the other 61B of the two first sides 61 is referred to as the returning section.

[0063] In this case, the second part 52 of the return path part comes into contact with the output part 31 which comes into contact with the first part 51 of the outbound path part, and the first part 51 of the return path part comes into contact with the output part 31 which comes into contact with the second part 52 of the outbound path part.

[0064] In the electric actuator structure 20, when a voltage is applied between the pair of first electrodes 40A, 40B via wiring, the first pump portion 32A contracts and pushes the dielectric liquid therein to the output portion 31. Similarly, when a voltage is applied between the pair of second electrodes, the second pump portion 32B contracts and pushes the dielectric liquid therein to the output portion 31.

[0065] As a result, the internal pressure of the output portions 31 increases due to the dielectric liquid flowing in from the first pump portion 32A and the second pump portion 32B, causing the output portions 31 to expand. As a result, the string member 50 is wound inside the frame body 60.

[0066] Such an electric actuator structure 20 is capable of lifting an object by fixing the object to the free end of the string member 50 and applying a voltage between the first electrodes 40A, 40B and between a pair of second electrodes.

[0067] Furthermore, by stopping the application of voltage between the first electrodes 40A, 40B and between the pair of second electrodes, the electric actuator structure 20 can return the object to the position it was in before it was pulled up.

[0068] Furthermore, the electric actuator structure 20 simultaneously deforms (expands) multiple output parts 31 to pull the string member 50 into the frame body 60, so the length of the string member 50 pulled into the frame body 60 can be made longer than in an electric actuator structure that deforms a single output part.

[0069] In addition, since the dielectric liquid is discharged to multiple output sections 31 by two pump sections, the first pump section 32A and the second pump section 32B, the output sections 31 can be expanded more efficiently than when the dielectric liquid is discharged to multiple output sections 31 by a single pump section.

[0070] Furthermore, if the string member 50 is thin and string-like, when the flexible output part 31 expands, the string member 50 will bite into the expanded output part 31. In this case, the electric actuator structure 20 cannot efficiently convert the expansion force of the output part 31 into a retraction force of the string member 50.

[0071] Therefore, the string member 50 according to the embodiment has a wide band shape in the second direction B. Therefore, even if the flexible output section 31 expands, the string member 50 is less likely to bite into the expanded output section 31. This allows the electric actuator structure 20 to efficiently convert the expansion force of the output section 31 into a retraction force of the string member 50.

[0072] Here, when the end of the first pump section 32A in the second direction B that is closest to the multiple output sections 31 is defined as the first end, and the end that is farthest from the multiple output sections 31 is defined as the second end, the first pump section 32A is configured as shown in Figure 17.

[0073] Specifically, the first pump section 32A is configured such that the dimension L of the first pump section 32A in a third direction perpendicular to the first direction A and the second direction B decreases from the first end to the second end. In this case, the second pump section 32B has the same configuration as the first pump section 32A.

[0074] As a result, the first pump section 32A and the second pump section 32B can improve the discharge capacity of the dielectric liquid compared to when the dimension L of the first pump section 32A in the third direction is uniform, based on the same principle as the pump section 4 shown in Figure 13.

[0075] 18. Specifically, the first pump section 32 may be configured such that two first electrodes 40A, 40B, which are arranged opposite each other across the first pump section 32A, are curved concavely toward each other at second ends farther from the output section 31. In this case, the second pump section 32B has the same configuration as the first pump section 32A.

[0076] As a result, the first pump section 32A and the second pump section 32B can improve the discharge capacity of the dielectric liquid compared to when the pair of first electrodes 40A, 40B and the pair of second electrodes are flat and not curved, based on the same principle as the pump section 4 shown in Figure 13.

[0077] The present technology can be configured as follows. (1) An electrostatic actuator structure in which a plurality of electrostatic actuators are connected and lined up in a first direction in a plane, wherein the electrostatic actuators include: a flexible pump portion having a first surface and a second surface opposite the first surface; a dielectric liquid located inside the pump portion; a first electrode located on the first surface; a second electrode located on the second surface; an output portion provided at a position away from the pump portion and whose shape changes in response to a change in internal pressure; and a passage portion communicating between an interior of the pump portion and an interior of the output portion, wherein the plurality of output portions are lined up in the first direction, and the output portion has a first member constituting an upper surface, a second member constituting a lower surface, and a welded portion where the first member and the second member are welded at peripheral portions of the first member and the second member, and the welded portion has a wide portion where a weld width at at least a part of a pair of first sides lined up in the first direction is larger than a weld width at a pair of second sides lined up in a second direction perpendicular to the first direction in the plane. (2) The electrostatic actuator structure according to (1), wherein the pump portion, the output portion, and the passage portion of the electrostatic actuator are aligned along the second direction. (3) The electrostatic actuator structure according to (2), wherein the electrostatic actuators whose pump portion is located on one side of the output portion in the second direction and the electrostatic actuators whose pump portion is located on the other side of the output portion in the second direction are aligned alternately along the first direction. (4) The electrostatic actuator structure according to any one of (1) to (3), wherein the second side is curved convexly in a direction from the inside to the outside of the output portion.(5) The electrostatic actuator structure according to any one of (1) to (4), wherein the first electrode includes a first individual electrode arranged on one side of the first surface in a direction perpendicular to an arrangement direction of the pump portion, the output portion, and the passage portion in the plane, and a second individual electrode arranged on the other side of the first surface in the direction perpendicular to the arrangement direction, and the second electrode includes a third individual electrode arranged to face the first individual electrode across the pump portion, and a fourth individual electrode arranged to face the second individual electrode across the pump portion. (6) The electrostatic actuator structure according to any one of (1) to (4), wherein, when an end of both ends of the pump portion in the arrangement direction of the pump portion, the output portion, and the passage portion that is closer to the passage portion is defined as a first end, and an end that is farther from the passage portion is defined as a second end, the distance between the first electrode and the second electrode increases from the second end to the first end. (7) The electrostatic actuator structure according to any one of (1) to (4), wherein, when an end of the pump section in an arrangement direction of the pump section, the output section, and the passage section that is closer to the passage section is defined as a first end and an end that is farther from the passage section is defined as a second end, a flow path width that is a dimension of the pump section in a direction perpendicular to the arrangement direction in the plane increases from the second end toward the first end. (8) An electrostatic actuator comprising: a flexible shell; a dielectric liquid located inside the shell; a plurality of electrodes; and a string member, wherein the shell includes a plurality of output sections spaced apart along a first direction; and a pump section located in a second direction perpendicular to the first direction relative to the plurality of output sections, wherein at least two of the plurality of electrodes are arranged opposite each other with the pump section interposed therebetween, and when a direction perpendicular to the first direction and the second direction is defined as a third direction, the string member is hung across the plurality of output sections such that a first portion located on one side of the output section in the third direction and a second portion located on the other side of the output section in the third direction are alternately repeated along the first direction.(9) The electrostatic actuator according to (8), wherein the pump section includes a first pump section arranged on one side of the plurality of output sections in the second direction, and a second pump section arranged on the other side of the plurality of output sections in the second direction, and the plurality of electrodes include a pair of first electrodes arranged opposite each other with the first pump section therebetween, and a pair of second electrodes arranged opposite each other with the second pump section therebetween. (10) The electrostatic actuator according to (8) or (9), further comprising: a frame body surrounding the shell from the first direction and the second direction; the frame body including two first sides located on one side and the other side of the shell in the first direction; and two second sides located on one side and the other side of the shell in the second direction; and the string member has one end fixed to one of the two first sides, and when viewed from the one end as a starting point, is hung across the plurality of output sections so that the first portion and the second portion alternate along the first direction, and is then folded back so as to straddle the other of the two first sides, and is hung across the plurality of output sections again so that the first portion and the second portion alternate along the first direction. (11) The electrostatic actuator according to (10), wherein, when the portion of the string member from the one end to the portion folded back at the other of the two first sides is defined as an outgoing path portion and the portion after being folded back at the other of the two first sides is defined as a returning path portion, the second portion of the returning path portion contacts the output portion that contacts the first portion of the outgoing path portion, and the first portion of the returning path portion contacts the output portion that contacts the second portion of the outgoing path portion. (12) The electrostatic actuator according to any one of (8) to (11), wherein the string member has a wide band shape in the second direction. (13) The electrostatic actuator according to any one of (8) to (12), wherein, when an end of both ends of the pump portion in the second direction that is closer to the multiple output portions is defined as a first end and an end that is farther from the multiple output portions is defined as a second end, the dimension of the pump portion in the third direction decreases from the first end to the second end.(14) The electrostatic actuator according to (13), wherein the two electrodes disposed opposite each other with the pump portion interposed therebetween are concavely curved in the directions approaching each other at the second end.

[0078] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0079] 2 Electric actuator structure 3 Electric actuator 4 Pump section 5 Output section 6 Passage section

Claims

1. An electrostatic actuator structure in which a plurality of electrostatic actuators are connected and lined up in a first direction in a plane, wherein the electrostatic actuators comprise: a flexible pump section having a first surface and a second surface opposite the first surface; a dielectric liquid located inside the pump section; a first electrode located on the first surface; a second electrode located on the second surface; an output section provided at a position away from the pump section and whose shape changes in response to changes in internal pressure; and a passage section connecting the interior of the pump section and the interior of the output section, wherein the plurality of output sections are lined up in the first direction, and the output section has a first member constituting an upper surface, a second member constituting a lower surface, and welded portions where the first member and the second member are welded at peripheral portions of the first member and the second member, and the welded portions have wide portions where the weld width at at least a part of a pair of first sides aligned in the first direction is larger than the weld width at a pair of second sides aligned in a second direction perpendicular to the first direction in the plane.

2. The electrostatic actuator structure according to claim 1, wherein the pump portion, the output portion, and the passage portion of the electrostatic actuator are aligned along the second direction.

3. An electrostatic actuator structure as described in claim 2, wherein the electrostatic actuators in which the pump portion is located on one side of the output portion in the second direction and the electrostatic actuators in which the pump portion is located on the other side of the output portion in the second direction are arranged alternately along the first direction.

4. The electrostatic actuator structure according to claim 1, wherein the second side is curved convexly in a direction from the inside to the outside of the output section.

5. An electrostatic actuator structure according to any one of claims 1 to 4, wherein the first electrode includes a first individual electrode arranged on one side of the first surface in a direction perpendicular to the arrangement direction of the pump section, the output section, and the passage section within the plane, and a second individual electrode arranged on the other side of the first surface in the direction perpendicular to the arrangement direction, and the second electrode includes a third individual electrode arranged opposite the first individual electrode with the pump section in between, and a fourth individual electrode arranged opposite the second individual electrode with the pump section in between.

6. An electrostatic actuator structure according to any one of claims 1 to 4, wherein, when the end of the pump section in the arrangement direction of the pump section, the output section, and the passage section that is closest to the passage section is defined as a first end, and the end that is farthest from the passage section is defined as a second end, the distance between the first electrode and the second electrode increases from the second end toward the first end.

7. An electrostatic actuator structure according to any one of claims 1 to 4, wherein, when the end of the pump section in the arrangement direction of the pump section, the output section, and the passage section that is closest to the passage section is defined as a first end, and the end that is farthest from the passage section is defined as a second end, the flow path width that is the dimension of the pump section in a direction perpendicular to the arrangement direction in the plane increases from the second end toward the first end.

Images