Switching element and method for manufacturing magnetic liquid metal

Abstract

Provided is a switching element of which ON and OFF operations can be easily controlled by the movement of a liquid metal. The switching element is configured to comprise: a magnetic liquid metal (13) containing a liquid metal and particles of a magnetic material; a container (11) in which the magnetic liquid metal (13) is movably disposed; and a plurality of terminals (12A, 12B) each having one end sealed in the container (11), wherein conduction between the plurality of terminals (12A, 12B) is switched by the movement of the magnetic liquid metal (13).

Description

Switching element and method for manufacturing magnetic liquid metal

[0001] The present invention relates to a switching element.

[0002] Electric switches have been proposed that use a liquid metal such as liquid gallium or a gallium alloy as a conductive liquid and switch conduction between terminals by the movement of the liquid metal. The electric switch described in Patent Document 1 below describes a configuration in which, in order to prevent wetting of the switch container, liquid gallium or a gallium alloy that does not contain metal oxide or that contains only a trace amount of metal oxide is sealed in the switch container together with an inert gas.

[0003] Japanese Special Publication No. 8-510082

[0004] However, in the above-mentioned electric switch configuration, the movement of the liquid metal is basically natural movement due to gravity, and the switch is turned on and off by tilting the switch container, which results in the problem that it is difficult to control the on and off of the electric switch.

[0005] In one aspect, the present invention has been made in consideration of the above problems, and has an object to provide a switching element that can easily control the ON / OFF operation by the movement of liquid metal.

[0006] In order to solve the above-mentioned problems, the present invention employs the following configuration.

[0007] That is, a switching element according to one aspect of the present invention comprises a magnetic liquid metal containing liquid metal and particles of a magnetic material, a container in which the magnetic liquid metal is movably arranged, and a plurality of terminals having one end sealed within the container, and switches conductivity between the plurality of terminals by the movement of the magnetic liquid metal.

[0008] A switching device according to one aspect of the present invention includes the switching element according to the above aspect, an electromagnet that applies a magnetic force to the magnetic liquid metal, and a magnetic force control unit that controls the application of current to the electromagnet.

[0009] A method for producing a magnetic liquid metal according to one aspect of the present invention is a method for producing the magnetic liquid metal provided in the switching element according to the above aspect, and includes a pouring step of pouring particles of a magnetic material and a stirring bar into liquid metal in a stirring vessel, and a stirring step of stirring using the stirring bar and a stirrer for a predetermined period of time at a speed of 300 rpm or more and 3600 rpm or less, thereby mixing and dispersing the particles of the magnetic material into the liquid metal.

[0010] According to the present invention, it is possible to provide a switching element that can easily control the ON / OFF operation by the movement of liquid metal.

[0011] 1 is a diagram schematically illustrating an example of a schematic configuration and an operation example of a switching device according to embodiment 1. FIG. 2 is a flowchart illustrating an example of a method for manufacturing a magnetic liquid metal. FIG. 3 is a diagram schematically illustrating an example of a schematic configuration and an operation example of a switching device according to embodiment 2.

[0012] Hereinafter, a first embodiment and a second embodiment of the present invention will be described in detail with reference to the drawings. The same or equivalent components and members shown in each drawing are designated by the same reference numerals, and redundant explanations will be omitted where appropriate. In addition, in Figures 1 and 3, the vertical direction, i.e., the direction of gravity, is defined as the up-down direction.

[0013] §1 Application Examples [Embodiment 1] First, an example of a switching device to which the present invention is applied will be described using Fig. 1. Fig. 1 is a diagram schematically showing an example of the general configuration and operation of a switching device 1 according to embodiment 1. As shown on the left side of Fig. 1, the switching device 1 according to embodiment 1 is composed of a switching element 2, an electromagnet 3, and a magnetic force control unit 5. The switching element 2 includes a container 11, two terminals 12A and 12B, and a magnetic liquid metal 13 disposed within the container 11, and the container 11 is filled with a fluorine-based inert liquid 15.

[0014] The container 11 is formed in a thin box-like shape, approximately rectangular in a front view and elongated in the vertical direction. One end of each of the terminals 12A and 12B is inserted into the upper wall of the container 11 and sealed therein. The magnetic liquid metal 13 is a magnetic liquid metal, and by applying a magnetic force to the magnetic liquid metal 13 from an external magnetic source such as an electromagnet or permanent magnet, the magnetic liquid metal 13 can be moved toward the magnetic source. When no external magnetic force is applied, the magnetic liquid metal 13 is located on the lower side of the container 11 in the direction of gravity, i.e., on the bottom side.

[0015] The fluorine-based inert liquid 15 can prevent the magnetic liquid metal 13 from wetting the terminals 12A, 12B and the inner surface of the container 11. The fluorine-based inert liquid 15 is also effective in insulating between the terminals 12A, 12B and preventing arcing.

[0016] 1, in the first embodiment, an electromagnet 3 is disposed near the upper side of the container 11. The electromagnet 3 includes a coil 21, a rod-shaped core 22 inserted into the coil 21, a switch 23, and a battery 25 electrically connected to the coil 21 via the switch 23. The core 22 is made of a ferromagnetic material such as iron.

[0017] Furthermore, the magnetic force control unit 5 switches the conductive state of the switch 23 based on an external input. For example, the magnetic force control unit 5 may switch the conductive state of the switch 23 based on an externally input electrical signal, or may switch the conductive state of the switch 23 based on an external physical force. In this way, the magnetic force control unit 5 can control the ON / OFF of the electromagnet 3.

[0018] §2 Configuration Example Next, the material of the container 11 will be described. The container 11 is made of fluororesin. The container 11 is formed into a hollow box shape, and is configured so that the magnetic liquid metal 13 can move up and down. This improves the wettability of the magnetic liquid metal 13 to the inner wall of the container 11.

[0019] The container 11 may be made of other resin materials such as polypropylene, polyethylene, or acrylic resin, and the inside may be coated with fluorine, thereby improving the wettability of the magnetic liquid metal 13 to the inner wall of the container 11.

[0020] Each of the terminals 12A, 12B is made of tungsten. This prevents corrosion of the terminals 12A, 12B due to the magnetic liquid metal 13, thereby extending their lifespan. The terminals 12A, 12B are inserted into the container 11 with one end thereof parallel to each other and spaced a predetermined distance, for example, about 1 to 5 mm, from each other. The terminals 12A, 12B are arranged parallel to each other and spaced apart so that they can be short-circuited by the magnetic liquid metal 13 moving upward within the container 11. The other end of each of the terminals 12A, 12B is bent outward at a substantially right angle at the top end of the container 11, allowing an electromagnet 3 to be placed near the top of the container 11.

[0021] Next, we will explain the magnetic liquid metal 13. The magnetic liquid metal 13 contains liquid metal and particles of a magnetic material. In other words, the magnetic liquid metal 13 is a liquid metal in which particles of a magnetic material are mixed and dispersed.

[0022] The liquid metal contained in the magnetic liquid metal 13 includes mercury, gallium, and gallium alloys. In the first embodiment, gallium and gallium alloys are used as non-toxic substitutes for mercury. Gallium alloys include alloys containing gallium, tin, and indium. Gallium alloys may further contain zinc, bismuth, gold, silver, aluminum, etc.

[0023] The magnetic material contained in the magnetic liquid metal 13 is made of at least one of iron, nickel, cobalt, stainless steel, and rare earth magnets. Rare earth magnets include samarium-cobalt magnets, neodymium magnets, praseodymium magnets, and samarium-iron-nitrogen magnets. Furthermore, the magnetic material particles may be surface-treated with easily soluble materials such as zinc or nickel.

[0024] The content of the magnetic material in the magnetic liquid metal 13 is set to 1 part by weight or more and 15 parts by weight or less. In other words, if the weight of gallium or a gallium alloy is taken as 100, the weight of the magnetic material is set to be mixed in a ratio of 1 to 15. If the content of the magnetic material is less than 1 part by weight, the magnetic flux density of the magnetic liquid metal 13 will be less than 1 mT. As a result, the magnetic liquid metal 13 will be less magnetized by magnetic force and will no longer respond to magnetic force. Furthermore, if the content of the magnetic material is more than 15 parts by weight, the viscosity of the magnetic liquid metal 13 will exceed 100 Pa·s, and its responsiveness to magnetic force will decrease.

[0025] Therefore, by setting the content of the magnetic material in the magnetic liquid metal 13 to 1 part by weight or more, the magnetic liquid metal 13 has a magnetic flux density of, for example, 1 mT or more, which allows it to be moved by an external magnetic source. Furthermore, by setting the content of the magnetic material in the magnetic liquid metal 13 to 15 parts by weight or less, the magnetic liquid metal 13 has a viscosity of, for example, 100 Pa s or less, which allows it to be moved by an external magnetic source, and is in a liquid physical state. This allows for easy control of the ON / OFF operation of the switching element 2.

[0026] The particle diameter of the magnetic material is set to 1 μm or more and 100 μm or less. If the particle diameter of the magnetic material is smaller than 1 μm, the thixotropy of the magnetic liquid metal 13 increases. Therefore, even if the magnetic liquid metal 13 stops at the upper side of the container 11 due to the application of magnetic force and the application of magnetic force is stopped, the magnetic liquid metal 13 adheres to the terminals 12A and 12B, etc., making it difficult to move in the direction of gravity, and reducing responsiveness to the magnetic force. If the particle diameter of the magnetic material is larger than 100 μm, the storage stability of the magnetic material in the magnetic liquid metal 13 decreases, and the magnetic material particles settle to the bottom of the container, reducing responsiveness to the magnetic force.

[0027] Therefore, by setting the particle size of the magnetic material in the magnetic liquid metal 13 to be 1 μm or more and 100 μm or less, it is possible to suppress an increase in thixotropy, reduce viscosity, improve responsiveness, and prevent precipitation of the magnetic material dispersed in the magnetic liquid metal 13. This ensures reliable ON / OFF operation of the switching element 2.

[0028] Next, a method for manufacturing the magnetic liquid metal 13 will be described with reference to FIG. 2. FIG. 2 is a flowchart showing an example of a method for manufacturing the magnetic liquid metal 13. When manufacturing the magnetic liquid metal 13 having components suitable for use in the switching element 2, simply adding particles of a magnetic material to the liquid metal and stirring it will not result in a uniformly mixed state. In contrast, the inventors of the present application have discovered that a uniformly mixed state can be achieved by performing processing under the following conditions.

[0029] 2, first, in step S11, an operator puts liquid metal, magnetic material powder, i.e., magnetic material particles, and a stirring bar (not shown) into a stirring vessel (not shown) (putting step). Then, the operator proceeds to the process of step S12.

[0030] In step S12, the operator places the stirring container on a stirrer (not shown). Then, the operator starts stirring using the stirrer at a rotation speed of the stirrer of 300 rpm or more and 3600 rpm or less (stirring step). Then, the operator proceeds to the process of step S13.

[0031] In step S13, the operator determines whether a predetermined time, for example, 5 to 60 minutes, has elapsed since the start of stirring. If the operator determines that the predetermined time has not elapsed since the start of stirring (S13: NO), the operator executes the process of step S13 again.

[0032] On the other hand, if the operator determines that a predetermined time has elapsed since the start of stirring (S13: YES), the operator proceeds to step S14. In step S14, the operator stops stirring with the stirrer and stirring bar and then ends the process. This allows the operator to mix the magnetic material particles into the liquid metal in an appropriate and uniformly dispersed manner. Therefore, by using the magnetic liquid metal 13 manufactured in this manner, a switching element 2 capable of performing smooth and stable switching operation can be realized.

[0033] §3 Example of Operation Next, an example of the operation of the switching element 2 configured as described above will be described with reference to Figure 1. As shown on the left side of Figure 1, the magnetic force control unit 5 sets the switch 23 to OFF, thereby setting the electromagnet 3 to OFF. As a result, the magnetic liquid metal 13 in the container 11 moves downward in the direction of gravity, i.e., toward the bottom, and the terminals 12A and 12B are not conductive. Therefore, the magnetic force control unit 5 can set the switching element 2 to OFF by setting the switch 23 to OFF.

[0034] 1, the magnetic force control unit 5 sets the switch 23 to ON to turn on the electromagnet 3. As a result, a magnetic force is applied to the magnetic liquid metal 13 in the container 11, causing it to move upward in the container 11, and the terminals 12A and 12B are short-circuited by the magnetic liquid metal 13, establishing electrical continuity. Therefore, by setting the switch 23 to ON, the magnetic force control unit 5 can set the switching element 2 to ON.

[0035] Therefore, the magnetic force control unit 5 can control the application of magnetic force to the magnetic liquid metal 13 by controlling the application of current to the electromagnet 3. As a result, the magnetic force control unit 5 can move the magnetic liquid metal 13 in the container 11 in the vertical direction, and easily switch the conduction between the terminals 12A and 12B. This allows the magnetic force control unit 5 to easily and appropriately control the ON / OFF operation of the switching element 2 via the electromagnet 3.

[0036] §4 Modifications [Embodiment 2] Next, a switching device 31 according to embodiment 2 will be described with reference to Fig. 3. Fig. 3 is a diagram schematically illustrating an example of the general configuration and operation of the switching device 31 according to embodiment 2. For ease of explanation, components having the same functions as those described in the switching device 1 according to embodiment 1 above will be denoted by the same reference numerals, and their description will not be repeated.

[0037] 3, the switching device 31 according to the second embodiment is composed of a switching element 32, an electromagnet 33, and a magnetic force control unit 5. The switching element 32 includes a tube 41 as a container, two terminals 42A and 42B, and a magnetic liquid metal 13 disposed within the tube 41, and the tube 41 is filled with a fluorine-based inert liquid 15.

[0038] The tube 41 is formed in a generally semicircular arc shape in a front view, protruding downward in the direction of gravity. Alternatively, the tube 41 may be formed in a generally U-shape in a front view, protruding downward in the direction of gravity. One end of each of the terminals 42A, 42B is inserted into the tube 41 from both ends thereof and sealed therein. Wiring 43 is electrically connected to the other end of each of the terminals 42A, 42B.

[0039] The terminals 42A, 42B are arranged facing each other with one end thereof spaced a predetermined distance, for example, about 1 mm to about 5 mm, at a position above the lower end of the tube 41 by a predetermined height, for example, about 5 mm to about 10 mm. Furthermore, when no magnetic force is applied from the outside by the electromagnet 33, the magnetic liquid metal 13 is located below the opposing one end of the terminals 42A, 42B, i.e., on the bottom side.

[0040] The fluorine-based inert liquid 15 can make it difficult for the magnetic liquid metal 13 to wet the terminals 42A, 42B and the inner surface of the tube 41. The fluorine-based inert liquid 15 is also effective in insulating between the ends of the terminals 42A, 42B and preventing arcing.

[0041] 3, the electromagnet 33 includes an electromagnetic holder 35, a switch 23, and a battery 25 electrically connected to the electromagnetic holder 35 via the switch 23. In the second embodiment, the electromagnetic holder 35 is disposed in a position near the outer circumferential surface of the tube 41 at a predetermined height above the lower end of the tube 41 so as to face between one ends of the terminals 42A and 42B.

[0042] The electromagnetic holder 35 incorporates a coil wound around a core made of a ferromagnetic material such as iron, and can apply a magnetic force when current flows from the battery 25 via the switch 23. The magnetic force control unit 5 is also electrically connected to the switch 23 and can turn the switch 23 on and off. Thus, the magnetic force control unit 5 can control the on and off of the electromagnet 33 by controlling the on and off of the switch 23.

[0043] Next, the material of the tube 41 will be described. The tube 41 is made of fluororesin. The tube 41 is configured so that the magnetic liquid metal 13 can move upward from the lower end. This improves the wettability of the magnetic liquid metal 13 to the inner wall of the tube 41.

[0044] The tube 41 may be made of other resin materials such as polypropylene, polyethylene, acrylic resin, or silicone resin, and the inside may be coated with fluorine, thereby improving the wettability of the magnetic liquid metal 13 to the inner wall of the tube 41.

[0045] Each of the terminals 42A, 42B is made of tungsten. This prevents corrosion of each of the terminals 42A, 42B due to the magnetic liquid metal 13, thereby extending their lifespan. Furthermore, each of the terminals 42A, 42B is disposed facing each other with one end spaced apart by a predetermined distance, for example, approximately 1 to 5 mm. This allows each of the terminals 42A, 42B to be short-circuited by the magnetic liquid metal 13 that has been moved upward by a predetermined height within the tube 41 due to the magnetic force applied by the electromagnetic holder 35.

[0046] Next, an example of the operation of the switching element 32 configured as described above will be described with reference to Fig. 3. As shown on the left side of Fig. 3, the magnetic force control unit 5 sets the switch 23 to OFF, thereby setting the electromagnetic holder 35 to OFF. As a result, the magnetic liquid metal 13 in the tube 41 moves downward in the direction of gravity, i.e., toward the lower end of the tube 41, and the terminals 42A and 42B are not conductive. Therefore, the magnetic force control unit 5 can set the switching element 32 to OFF by setting the switch 23 to OFF.

[0047] 3, the magnetic force control unit 5 sets the switch 23 to ON and sets the electromagnetic holder 35 to ON. As a result, the magnetic liquid metal 13 located at the lower end of the tube 41 is subjected to magnetic force and moves to a position facing the electromagnetic holder 35, and the terminals 42A and 42B are short-circuited by the magnetic liquid metal 13 and become conductive. Therefore, by setting the switch 23 to ON, the magnetic force control unit 5 can set the switching element 32 to ON.

[0048] Therefore, the magnetic force control unit 5 can control the application of magnetic force to the magnetic liquid metal 13 by controlling the application of current to the electromagnetic holder 35 of the electromagnet 33. As a result, the magnetic force control unit 5 can move the magnetic liquid metal 13 in the tube 41 from the lower end of the tube 41 to a position facing the electromagnetic holder 35, and easily switch the conduction between the terminals 42A and 42B. This allows the magnetic force control unit 5 to easily control the ON / OFF operation of the switching element 32 via the electromagnet 33.

[0049] [Modification 1] In the switching device 1 according to the first embodiment, the switching element 2 and the electromagnet 3 may be integrated. Specifically, for example, a core 22 around which the coil 21 is wound may be attached along the upper edge of the side wall of the container 11. This allows the switching device 1 to be made smaller.

[0050] [Variation 2] In the switching device 1 according to embodiment 1, electromagnets 3 may be disposed near the top of the container 11 and near the bottom of the container 11. The magnetic force control unit 5 may be electrically connected to the switch 23 of each electromagnet 3 so that each switch 23 can be turned ON and OFF individually. This allows the magnetic force control unit 5 to change the switch 23 of the upper electromagnet 3 from ON to OFF and the switch 23 of the lower electromagnet 3 from OFF to ON. This allows the magnetic liquid metal 13 to fall faster than gravity through the fluorine-based inert liquid 15. This increases the response speed of the switching element 2.

[0051] In the switching device 31 according to the second embodiment, the electromagnetic holders 35 of the electromagnets 33 may be disposed near the outer circumferential surface of the tube 41 at an upper position where one end of each of the terminals 42A and 42B of the tube 41 faces each other, and at a position facing the lower end of the tube 41. The magnetic force control unit 5 may be electrically connected to the switches 23 of the electromagnets 33 so that each switch 23 can be turned on and off individually.

[0052] As a result, the magnetic force control unit 5 sets the switch 23 of the upper electromagnet 33 from ON to OFF, and sets the switch 23 of the lower electromagnet 33 from OFF to ON. As a result, the magnetic liquid metal 13 can be caused to fall faster than the natural fall through the fluorine-based inert liquid 15. As a result, the response speed of the switching element 32 can be increased.

[0053] The present invention is not limited to the above-described embodiments, 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.

[0054] [Additional Notes] The switching element of the first embodiment comprises a magnetic liquid metal containing liquid metal and particles of a magnetic material, a container in which the magnetic liquid metal is movably arranged, and a plurality of terminals having one end sealed within the container, and switches the conductivity between the plurality of terminals by the movement of the magnetic liquid metal.

[0055] According to the above configuration, since the magnetic liquid metal contains particles of a magnetic material, it is possible to apply a magnetic force to the magnetic liquid metal from an external magnetic source such as an electromagnet or permanent magnet, thereby moving the magnetic liquid metal toward the magnetic source. As a result, by controlling the application of magnetic force to the magnetic liquid metal from the magnetic source such as an electromagnet or permanent magnet, it is possible to move the magnetic liquid metal and easily switch conduction between terminals. This makes it possible to easily control the ON / OFF operation of the switching element by the movement of the magnetic liquid metal.

[0056] In a second aspect, the switching element of the first aspect is provided, wherein the liquid metal contains at least gallium. According to the above configuration, it is possible to provide a switching element using a magnetic liquid metal that does not use mercury and has no adverse effects on the environment.

[0057] A third aspect is the switching element of the first or second aspect, wherein the magnetic material is made of at least one of iron, nickel, cobalt, stainless steel, and a rare earth magnet. With this configuration, the magnetic material can be made of relatively easily available materials.

[0058] A fourth aspect is the switching element according to any one of the first to third aspects, wherein the content of the magnetic material is 1 part by weight or more and 15 parts by weight or less.

[0059] According to the above configuration, the content of the magnetic material is 1 to 15 parts by weight. As a result, since the magnetic liquid metal is 1 part by weight or more, the magnetic flux density that can be moved by an external magnetic source is, for example, 1 mT or more. Furthermore, since the magnetic liquid metal is 15 parts by weight or less, the viscosity that can be moved by an external magnetic source is, for example, 100 Pa s or less, and the physical state is liquid. This makes it easy to control the ON / OFF operation of the switching element.

[0060] A fifth aspect is the switching element according to any one of the first to fourth aspects, wherein the particle diameter of the magnetic material is 1 μm or more and 100 μm or less.

[0061] According to the above configuration, the particle diameter of the magnetic material is 1 μm to 100 μm, which suppresses an increase in thixotropy, reduces viscosity, improves responsiveness, and prevents the magnetic material dispersed in the magnetic liquid metal from settling, thereby ensuring reliable ON / OFF operation of the switching element.

[0062] A sixth aspect is a switching element according to any one of the first to fifth aspects, wherein the terminals are arranged in the container so that their longitudinal directions are parallel to each other, and are arranged in parallel at intervals that allow short-circuiting by the magnetic liquid metal moving within the container.

[0063] According to the above configuration, the magnetic liquid metal moved within the container is placed at one of the positions in the region where the terminals are arranged in parallel to each other. This short-circuits the terminals, thereby widening the tolerance range for the placement of the magnetic liquid metal and improving the electrical continuity. In other words, by moving the magnetic liquid metal within the container using an external magnetic source such as an electromagnet or permanent magnet, the on / off control of the switching element can be easily and appropriately performed.

[0064] A seventh aspect is a switching element of any one of the first to fifth aspects, wherein the container includes a tube formed in a U-shape or semicircular arc shape when viewed from the front and protruding downward, and the plurality of terminals include a pair of terminals inserted into the tube from both ends thereof and arranged opposite each other at a position a predetermined height above the lower end of the tube, with the ends of each terminal spaced apart by a distance that allows short-circuiting by the magnetic liquid metal moving within the tube.

[0065] According to the above configuration, the pair of terminals are short-circuited by the magnetic liquid metal that has moved inside the tube to a position a predetermined height above the bottom end of the tube. This makes it easy to control the ON / OFF of the switching element by using an external magnetic source such as an electromagnet or permanent magnet to move the magnetic liquid metal inside the tube to a position a predetermined height above the bottom end of the tube.

[0066] In an eighth aspect, in the switching element of any one of the first to seventh aspects, the container is made of a fluororesin. According to the above configuration, since the container is made of a fluororesin, it is possible to improve the wettability of the magnetic liquid metal to the inner wall.

[0067] In a ninth aspect, in the switching element of any one of the first to seventh aspects, the container has an inner surface coated with fluorine. According to the above configuration, the container has an inner surface coated with fluorine, which can improve the wettability of the magnetic liquid metal to the inner wall.

[0068] A tenth aspect is the switching element of the eighth or ninth aspect, wherein the container is filled with a fluorine-based inert liquid together with the magnetic liquid metal. With this configuration, since the container is filled with a fluorine-based inert liquid together with the magnetic liquid metal, it is possible to improve the wettability of the magnetic liquid metal to the inner wall, to provide insulation, and to prevent arcing.

[0069] The switching device of an eleventh aspect includes the switching element according to the first aspect, an electromagnet that applies a magnetic force to the magnetic liquid metal, and a magnetic force control unit that controls the application of current to the electromagnet.

[0070] According to the above configuration, the magnetic force control unit can control the application of magnetic force to the magnetic liquid metal by controlling the application of current to the electromagnet, thereby moving the magnetic liquid metal and easily switching the conduction between the terminals. This allows the magnetic force control unit to easily control the ON / OFF operation of the switching element via the electromagnet.

[0071] A twelfth aspect of the present invention relates to a method for producing a magnetic liquid metal, which is provided in the switching element according to the first aspect, and includes the steps of: adding particles of a magnetic material and a stirring bar to the liquid metal in a stirring vessel; and stirring the liquid metal for a predetermined time at a speed of 300 rpm or more and 3600 rpm or less using the stirring bar and a stirrer to mix and disperse the particles of the magnetic material in the liquid metal. According to the above configuration, the particles of the magnetic material can be mixed and dispersed in the liquid metal by a simple method.

[0072] 1, 31: Water switching device, 2, 32: Switching element, 3, 33: Electromagnet, 5: Magnetic force control unit, 11: Container, 12A, 12B, 42A, 42B: Terminal, 13: Magnetic liquid metal, 15: Fluorine-based inert liquid, 41: Tube

Claims

1. A switching element comprising: a magnetic liquid metal containing liquid metal and particles of a magnetic material; a container in which the magnetic liquid metal is movably arranged; and a plurality of terminals having one end sealed within the container, wherein the switching element switches conductivity between the plurality of terminals by the movement of the magnetic liquid metal.

2. The switching element according to claim 1, wherein the liquid metal contains at least gallium.

3. The switching element according to claim 1, wherein the magnetic material is made of at least one of iron, nickel, cobalt, stainless steel, and a rare earth magnet.

4. The switching element according to claim 1, wherein the content of said magnetic material is from 1 part by weight to 15 parts by weight.

5. The switching element according to claim 1, wherein the particle diameter of the magnetic material is 1 μm or more and 100 μm or less.

6. A switching element as described in claim 1, wherein the multiple terminals are arranged within the container so that their longitudinal directions are parallel to one another and are arranged in parallel at intervals that allow short-circuiting by the magnetic liquid metal moving within the container.

7. A switching element as described in claim 1, wherein the container includes a tube formed in a U-shape or semicircular arc shape when viewed from the front and protruding downward, and the multiple terminals include a pair of terminals inserted into the tube from both ends thereof and positioned opposite each other at a position a predetermined height above the lower end of the tube, with the ends of each terminal spaced apart a distance that allows a short circuit by the magnetic liquid metal moving within the tube.

8. The switching element according to claim 1, wherein the container is made of a fluororesin.

9. The switching element of claim 1, wherein the container is internally fluorine coated.

10. A switching element according to claim 8 or 9, wherein the container is filled with a fluorine-based inert liquid together with the magnetic liquid metal.

11. A switching device comprising: the switching element according to claim 1; an electromagnet that applies a magnetic force to the magnetic liquid metal; and a magnetic force control unit that controls the application of a current to the electromagnet.

12. A method for producing the magnetic liquid metal provided in the switching element described in claim 1, comprising: a pouring step of pouring particles of a magnetic material and a stirring bar into the liquid metal in a stirring vessel; and a stirring step of stirring using the stirring bar and a stirrer at 300 rpm or more and 3600 rpm or less for a predetermined period of time, thereby mixing and dispersing the particles of the magnetic material into the liquid metal.

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