Actuator

Abstract

To realize lower voltage and increase of an extension rate.SOLUTION: An actuator comprises: a PVC gel sheet 21 formed like a sheet by gelatinous polyvinyl chloride; and sheet-like electrodes 22 having flexibility arranged, respectively on both sides of the PVC gel sheet 21. The actuator is constituted so that the PVC gel sheet 21 can extend in a surface direction when voltage is supplied to the PVC gel sheet 21 via the respective electrodes 22, in which a plurality of regulation members 23 which are formed like a belt by a material having inflexibility, and arranged to extend in a width direction on both sides of a dielectric sheet to regulate extension of the PVC gel sheet 21 in the width direction, are arranged in parallel along a length direction on both sides of the PVC gel sheet 21.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an actuator in which a dielectric sheet expands in a planar direction when a voltage is applied to the dielectric sheet via electrodes disposed on both sides of the dielectric sheet. [Background technology]

[0002] As this type of actuator, the applicant has disclosed a dielectric actuator in the following Patent Document 1. This dielectric actuator is configured to include a PVC gel sheet as a dielectric sheet and flexible electrodes provided on both sides of the PVC gel sheet, and expands in the planar direction when a voltage is supplied to the PVC gel sheet via the electrodes, and returns to its initial state when the voltage supply is stopped. In other words, this dielectric actuator is configured to perform expansion and contraction operations in the planar direction in response to the supply and stop of voltage supply. Furthermore, in this dielectric actuator, the ratio (expansion rate) of the difference in the area of ​​the electrodes before and after the application of a voltage to the area of ​​the electrodes in a state where no voltage is applied is large compared to a dielectric actuator using a dielectric elastomer instead of a PVC gel sheet, and it is possible to obtain an expansion rate of 12% when an applied voltage is 3000V. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-108601 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned dielectric actuator has the following problems to be solved. Specifically, the above-mentioned dielectric actuator using the PVC gel sheet can obtain a larger expansion rate than the dielectric actuator using the dielectric elastomer, but a voltage of 3000V needs to be applied to obtain a 12% expansion rate. On the other hand, this type of dielectric actuator is expected to be applied to devices worn by people, taking advantage of its flexibility. In order to realize application to such devices, it is necessary to reduce the voltage and generate a large expansion rate. However, the above-mentioned dielectric actuator requires the application of a high voltage of 3000V, and the expansion rate is only 12%, which is not sufficient, so there is a demand for a lower voltage and an increased expansion rate.

[0005] The present invention has been made in view of the above problems, and has as its main object to provide an actuator that can realize a lower voltage and an increased expansion / contraction ratio. [Means for solving the problem]

[0006] In order to achieve the above object, the actuator described in claim 1 is an actuator comprising a dielectric sheet formed in a sheet-like shape from gelled polyvinyl chloride, and flexible sheet-like electrodes disposed on both sides of the dielectric sheet, in which the dielectric sheet expands in a planar direction when a voltage is supplied to the dielectric sheet via the electrodes, and a restricting member formed in a linear or band-like shape from a material having low flexibility and disposed between at least one of the surfaces of the dielectric sheet and the electrode so as to extend in one direction on the at least one surface of the dielectric sheet, restricting the expansion of the dielectric sheet in the one direction, extending along a cross direction crossing the one direction on the at least one surface. Spaced Apart It is characterized in that multiple units are arranged in parallel. Effect of the Invention

[0012] According to the actuator of the present invention, by arranging a plurality of restricting members extending in one direction on the dielectric sheet in parallel along a cross direction crossing the one direction, the expansion and contraction of the dielectric sheet in the one direction can be restricted, and the expansion rate of the dielectric sheet in the cross direction can be sufficiently increased. Therefore, according to this actuator, even when the voltage is low, a sufficient expansion rate can be ensured, and thus a lower voltage and an increased expansion rate can be realized, compared to conventional actuators.

[0013] Furthermore, with this actuator, by applying pre-strain in one direction to the dielectric sheet, the expansion and contraction of the dielectric sheet in one direction can be more reliably regulated, and the expansion rate of the dielectric sheet in the cross direction can be further increased, resulting in further reduction in voltage and further increase in the expansion rate.

[0014] Furthermore, with this actuator, by arranging multiple regulating members side by side on both sides of the dielectric sheet, the expansion and contraction of the dielectric sheet in one direction can be more reliably regulated, and the expansion rate of the dielectric sheet in the cross direction can be further increased, resulting in further voltage reduction and further increase in the expansion rate.

[0015] Furthermore, according to this actuator, since the regulating member is made of paper, it is possible to form a lightweight regulating member having sufficient flexibility, and therefore it is possible to realize a reduction in the weight of the actuator.

[0016] Furthermore, with this actuator, since the electrodes are formed from a conductive oil compound, the electrodes can be formed by applying the conductive oil compound to the surface of the dielectric sheet, thereby simplifying the manufacturing process of the actuator compared to a configuration in which the electrodes are prepared in advance in a separate process.

[0017] Furthermore, with this actuator, the electrodes are formed from a mixture of gelled polyvinyl chloride and powdered carbon, so that prefabricated electrodes can be disposed on each surface of the dielectric sheet. This shortens the manufacturing time of the actuator compared to a configuration in which electrodes are formed by applying an electrode material to the surface of the dielectric sheet. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a plan view of the actuator 10. [Diagram 2] FIG. 2 is a diagram showing the configuration of an actuator 10. [Diagram 3] 1 is a flowchart of a PVC solution preparation process 50. [Figure 4] 4 is a flowchart of an actuator assembly process 60. [Diagram 5] FIG. 2 is a first explanatory diagram illustrating a method for manufacturing the actuator 10. [Figure 6] 11 is a second explanatory diagram illustrating the method for manufacturing the actuator 10. FIG. [Figure 7] 11 is a third explanatory diagram illustrating the method for manufacturing the actuator 10. FIG. [Figure 8] 13 is a fourth explanatory diagram illustrating the method for manufacturing the actuator 10. FIG. [Figure 9] 13 is a fifth explanatory diagram illustrating the manufacturing method of the actuator 10. FIG. [Figure 10] 13 is a sixth explanatory diagram illustrating the manufacturing method of the actuator 10. FIG. [Figure 11] FIG. 11 is a characteristic diagram showing the results of a characteristic test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an actuator according to the present invention

[0020] First, the configuration of the actuator 10 shown in Fig. 1 will be described. The actuator 10 is an example of an actuator according to the present invention, and as shown in Figs. 1 and 2, includes a PVC gel sheet 21, a pair of sheet-like electrodes 22 disposed on both sides of the PVC gel sheet 21, and a plurality of restricting members 23 formed in a belt shape (an example of a line or belt shape) and disposed on both sides (an example of at least one side) of the PVC gel sheet 21, and is formed in a belt shape (rectangle) as a whole.

[0021] The PVC gel sheet 21 is an example of the dielectric sheet of the present invention, and is made of polyvinyl chloride (PVC) and a plasticizer, has dielectric properties, and is in a gel state at room temperature. The PVC gel sheet 21 has the property of being deformed by the supply of voltage. The PVC gel sheet 21 is formed in a rectangular (strip) sheet shape, as shown in Figs. 1 and 2.

[0022] 1 and 2, the electrode 22 is formed in a rectangular (strip-like) sheet shape, and is conductive and flexible. In this embodiment, the electrode 22 is formed by applying a conductive oil compound made of silicone oil mixed with carbon to both sides of the PVC gel sheet 21.

[0023] The regulating member 23 is formed of a material having low flexibility. In this embodiment, the regulating member 23 is formed of paper. Moreover, as shown in Figs. 1 and 2, the regulating member 23 is formed in a belt shape (an example of a line or belt shape) and is arranged in parallel along the length direction of the PVC gel sheet 21 (an example of a cross direction intersecting (perpendicular to) the one direction) so as to extend in the width direction (an example of a one direction) of the PVC gel sheet 21 on both sides of the PVC gel sheet 21.

[0024] In this actuator 10, when a voltage is supplied to the PVC gel sheet 21 via each electrode 22, the PVC gel sheet 21 deforms so as to expand in the surface direction, and when the supply of voltage to the PVC gel sheet 21 is stopped, the PVC gel sheet 21 contracts in the surface direction accompanied by a force caused by the restoration (release of deformation) of the PVC gel sheet 21, and it is possible to output the force generated by the deformation of the PVC gel sheet 21 as a driving force. In addition, in this actuator 10, a plurality of restricting members 23 having low flexibility are arranged to extend in the width direction of the PVC gel sheet 21, so that the expansion and contraction in the width direction of the PVC gel sheet 21 is restricted. Therefore, in this actuator 10, the amount of expansion and contraction of the entire PVC gel sheet 21 is concentrated in the length direction by the amount that the expansion and contraction in the width direction of the PVC gel sheet 21 is restricted, and as a result, the PVC gel sheet 21 expands and contracts greatly in the length direction compared to a configuration in which the restricting members 23 are not provided.

[0025] Next, a method for manufacturing the actuator 10 will be described.

[0026] First, a method for producing a PVC solution that is a material for the PVC gel sheet 21 will be described with reference to the flow chart of the PVC solution production process 50 shown in Fig. 3. In this PVC solution production process 50, first, a solvent (tetrahydrofuran as an example) is measured and charged into a stirring vessel (step 51). The solvent is preferably used in the range of 600 to 1000 parts by weight per 100 parts by weight of polyvinyl chloride, and in this embodiment, 800 parts by weight of the solvent is used per 100 parts by weight of polyvinyl chloride.

[0027] Next, polyvinyl chloride is weighed and added to the stirring vessel containing the solvent while stirring (step 52). In this embodiment, 100 parts by weight of polyvinyl chloride is weighed and added to 800 parts by weight of the solvent.

[0028] Next, in a state where the polyvinyl chloride and the solvent are sufficiently mixed (dissolved), the plasticizer is weighed and added to the stirring vessel in which the polyvinyl chloride and the solvent are charged while being stirred (step 53). In this case, various plasticizers can be used, but in this embodiment, dibutyl adipate (DBA) is used. In addition, the plasticizer is preferably used in the range of 100 to 500 parts by weight per 100 parts by weight of polyvinyl chloride, and in this embodiment, 400 parts by weight of the plasticizer is used per 100 parts by weight of polyvinyl chloride. Next, the stirring vessel containing the polyvinyl chloride, the solvent, and the plasticizer (a mixture of these) is set in a defoaming device and a defoaming process is performed (step 54). With the above, the preparation of the PVC solution is completed.

[0029] Next, a method for assembling the actuator 10 will be described with reference to a flow chart of an actuator assembly process 60 shown in Fig. 4. In this actuator assembly process 60, first, as shown in Fig. 5, a PVC solution 200 is applied onto a glass plate and a film forming machine (applicator) is used to form a thin film of the PVC solution 200 on the glass plate, and then the PVC solution 200 is stored in an incubator and dried at 20°C for 5 days. As a result, a PVC gel sheet 21 is formed on the glass plate 100 (step 61).

[0030] Next, as shown in Fig. 6, the PVC gel sheet 21 on the glass plate is cut out into a predetermined shape (for example, a rectangle with a width of 20 mm and a length of 50 mm) using a cutter (step 62). Next, as shown in Fig. 7, the cut PVC gel sheet 21 is placed on the glass plate, and then the PVC gel sheet 21 is pulled in the width direction (left and right direction in the figure) to impart a pre-strain in the width direction (step 63). In this embodiment, a pre-strain of 150% (30 mm in this example) is imparted to the width before pulling (20 mm in this example) (i.e., pulled until the width becomes 50 mm).

[0031] Next, the regulating members 23 are attached (step 64). Specifically, as shown in FIG. 8, a plurality of regulating members 23 are arranged at equal intervals in the length direction (the vertical direction in the figure) so as to extend in the width direction of one surface of the PVC gel sheet 21. In this case, as an example, a piece of wood-free paper with a thickness of 70 μm cut into a strip shape with a width of 2 mm and a length of 50 mm is used as the regulating members 23. Next, both ends of the regulating members 23 and the edges of the PVC gel sheet 21 in the width direction are fixed with an adhesive tape 300. Next, the PVC gel sheet 21 is turned over, and a plurality of regulating members 23 are arranged on the other surface of the PVC gel sheet 21 in the above-mentioned procedure and fixed with the adhesive tape 300. Next, as shown in FIG. 9, the PVC gel sheet 21 to which the regulating members 23 are attached is cut into a predetermined shape (as an example, a rectangle with a width of 25 mm and a length of 40 mm) (step 65).

[0032] Next, the electrode 22 is formed (step 66). Specifically, as shown in FIG. 10, a conductive oil compound is applied to cover one surface of the PVC gel sheet 21 and the regulating member 23, and the conductive oil compound is left to stand until the fluidity of the conductive oil compound decreases. As a result, the electrode 22 is formed on one surface. Next, the PVC gel sheet 21 and the regulating member 23 with the electrode 22 formed on one surface are turned over, and a conductive oil compound is applied to cover the other surface, and the conductive oil compound is left to stand until the fluidity of the conductive oil compound decreases. As a result, the electrode 22 is formed on the other surface. Next, a lead wire (not shown) is connected to each electrode 22 (step 67). With the above, the actuator assembly process 60 is completed, and the actuator 10 is completed.

[0033] Next, the results of characteristic tests on the actuator according to the present invention will be described.

[0034] In the characteristic tests, the actuator 10 manufactured by the above-mentioned manufacturing method was designated as Example 1. Moreover, the actuator 10 manufactured with a pre-strain of 70% in the above-mentioned actuator assembly process 60 was designated as Example 2. Moreover, the actuator 10 without the restricting member 23 and without the pre-strain was designated as Comparative Example 1.

[0035] In this characteristic test, the expansion rate of the PVC gel sheet 21 in the length direction when a voltage was supplied to the PVC gel sheet 21 through each electrode 22 of each actuator 10 in Examples 1 and 2 and Comparative Example 1 was measured while changing the voltage value. In this case, the length of the PVC gel sheet 21 in the initial state where no voltage was supplied was L0, and the length of the PVC gel sheet 21 when a voltage was supplied was L1, and the value (%) represented by (L1-L0) / L0 was taken as the expansion rate. Furthermore, L0 and L1 in Examples 1 and 2 were taken as the lengths of only the portions where the regulating members 23 were not arranged (portions that contribute to expansion and contraction).

[0036] The results of the characteristic test are shown in Figure 11. It is clear from this figure that the actuator 10 of Example 1, in which a paper-made restricting member 23 is provided and a prestrain of 150% is applied, and the actuator 10 of Example 2, in which a paper-made restricting member 23 is provided and a prestrain of 70% is applied, have sufficiently large expansion / contraction rates at the same voltage value compared to the actuator 10 of Comparative Example 1, in which the restricting member 23 is not provided and no prestrain is applied. In other words, it is clear that by providing the restricting member 23 and applying prestrain, it is possible to achieve a sufficient reduction in voltage and a sufficient increase in the expansion / contraction rate.

[0037] As an additional characteristic test, an actuator 10 in which a paper restricting member 23 was provided and no pre-strain was applied was used as Example 3, and an actuator 10 in which a restricting member 23 made of a resin fiber with a diameter of 70 μm was provided and a pre-strain of 70% was applied was used as Example 4, and the expansion rate in the length direction of the PVC gel sheet 21 in each actuator 10 was measured while changing the voltage value (not shown). In the actuators 10 of Examples 3 and 4, the expansion rate at the same voltage value was sufficiently large compared to the actuator 10 of Comparative Example 1, but the expansion rate at the same voltage value was small compared to the actuators 10 of Examples 1 and 2.

[0038] In this way, according to this actuator 10, by arranging a plurality of restricting members 23 extending in the width direction of the PVC gel sheet 21 in parallel along the length direction, it is possible to restrict the expansion and contraction of the PVC gel sheet 21 in the width direction, thereby sufficiently increasing the expansion and contraction rate in the length direction of the PVC gel sheet 21. Therefore, according to this actuator 10, even when the voltage is low, a sufficient expansion and contraction rate can be ensured compared to conventional actuators, and as a result, it is possible to realize a lower voltage and an increased expansion and contraction rate.

[0039] Furthermore, according to this actuator 10, by applying a pre-strain to the PVC gel sheet 21, the expansion and contraction in the width direction of the PVC gel sheet 21 can be more reliably regulated, and the expansion rate in the length direction of the PVC gel sheet 21 can be further increased, thereby achieving a further reduction in voltage and a further increase in the expansion rate.

[0040] Furthermore, according to this actuator 10, by arranging a plurality of regulating members in parallel on both sides of the PVC gel sheet 21, it is possible to more reliably regulate the expansion and contraction in the width direction of the PVC gel sheet 21, and therefore it is possible to further increase the expansion rate in the length direction of the PVC gel sheet 21, thereby achieving a further reduction in voltage and a further increase in the expansion rate.

[0041] Furthermore, according to this actuator 10, since the restricting member 23 is made of paper, it is possible to form a lightweight restricting member having sufficient flexibility, and therefore it is possible to realize a reduction in the weight of the actuator 10.

[0042] Furthermore, according to this actuator 10, since the electrodes 22 are formed from a conductive oil compound, the electrodes 22 can be formed by applying the conductive oil compound to the surface of the PVC gel sheet 21, and therefore the manufacturing process of the actuator 10 can be simplified compared to a configuration in which the electrodes 22 are produced in a separate process and disposed on both sides of the PVC gel sheet 21.

[0043] The actuator 10 described above is an example of the actuator according to the present invention, and an appropriately modified configuration may be adopted. For example, in the actuator 10 described above, the restricting members 23 are disposed on both sides of the PVC gel sheet 21, but a configuration in which the restricting members 23 are disposed on only one side of the PVC gel sheet 21 may also be adopted. In addition, the actuator 10 described above is configured to include only one PVC gel sheet 21, but a configuration in which the actuator 10 includes a plurality of PVC gel sheets 21 and electrodes 22 disposed on both sides of each PVC gel sheet 21, and the restricting members 23 are disposed on at least one side of one or more PVC gel sheets 21 may also be adopted.

[0044] Furthermore, while the above-described actuator 10 employs the electrodes 22 formed from a conductive oil compound, it is also possible to employ electrodes 22 formed in a sheet shape from a mixture of gelled polyvinyl chloride and powdered carbon. With this configuration, prefabricated electrodes 22 can be disposed on each surface of the PVC gel sheet 21, and therefore the manufacturing time of the actuator 10 can be shortened compared to a configuration in which the electrodes 22 are formed by applying an electrode material to the surface of the PVC gel sheet 21.

[0045] In addition, in the configuration of the actuator 10 described above, the PVC gel sheet 21 and the electrodes 22 constituting the actuator 10 are each formed into a rectangle, but a configuration in which the PVC gel sheet 21 and the electrodes 22 are formed into other shapes in a plan view (for example, a circle, an ellipse, or a polygon other than a rectangle) can also be adopted.

[0046] In the above-described actuator 10, the width direction is defined as one direction, and the length direction perpendicular to the width direction is defined as the cross direction, and the regulating member 23 is disposed in that direction, but the one direction and the cross direction can be defined arbitrarily. For example, a direction inclined at an arbitrary angle (e.g., 30°) to the width direction can be defined as one direction, and a direction inclined at an arbitrary angle (e.g., 45°) to the one direction can be defined as the cross direction. [Explanation of symbols]

[0047] 10 Actuator 21 PVC gel sheet 22 electrodes 23 Regulatory Materials

Claims

[Claim 1] An actuator comprising a dielectric sheet formed in a sheet shape from gelled polyvinyl chloride, and flexible sheet-like electrodes disposed on both sides of the dielectric sheet, the dielectric sheet expanding in a planar direction when a voltage is supplied to the dielectric sheet via the electrodes, An actuator comprising a plurality of restricting members formed in a linear or band-like shape from a material having low flexibility, arranged between at least one of the surfaces of the dielectric sheet and the electrode so as to extend in a certain direction on the at least one surface of the dielectric sheet, and restricting the extension of the dielectric sheet in the certain direction, the restricting members being arranged in parallel at intervals along a cross direction that crosses the one direction on the at least one surface.

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