JP2010282886A - Liquid metal relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid metal relay capable of preventing the generation of arc upon opening between contact points. <P>SOLUTION: The liquid metal relay includes: a fixed contact point 2 made of liquid metal; a movable contact point 1 made of solid metal to be connected/disconnected to/from the fixed contact point 2; and an actuator 3 that moves the movable contact point 1 to be freely connected/disconnected to/from the fixed contact point 2. The movable contact point 1 is formed of: a low resistance section 10 that is provided on a side away from the fixed contact point 2 to come in contact with the fixed contact point 2 to be conductive when the contact points are closed; and a high resistance section 11 that is provided on a side closer to the fixed contact point 2 than the low resistance portion 10 is provided and has a higher resistance than the low resistance portion 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid metal relay that opens and closes a contact made of a solid metal and a contact made of a liquid metal.

  Conventionally, a relay that opens and closes between a fixed contact and a movable contact each made of a solid metal such as silver is known. In this type of relay, there is a possibility that an arc may be generated between the contacts when the contacts are closed and when the contacts are opened. For example, when the contact is closed, as shown in FIG. 7A, a leading arc (see FIG. 7A) or a bounce arc (see FIG. 7A) due to contact bounce is generated. Moreover, when opening between contacts, as shown in FIG.7 (b), a interruption | blocking arc (refer the same figure U) generate | occur | produces. Due to these arcs, the contact material melts and the contacts are welded in a state where the contacts are open, and the contacts cannot be opened, and there is a possibility that the contacts cannot be cut off. Further, the contact material may be melted or softened due to these arcs, and the contact material may be transferred or deformed. In this case, the contact resistance increases due to the change in the amount of overtravel between the contacts, which may cause conduction failure and malfunction.

  As a solution to the above problem, a relay that opens and closes a pair of contacts made of solid metal via a liquid metal made of mercury or the like is disclosed (for example, see Patent Document 1). An example of this type of relay will be described below.

  As shown in FIGS. 8A to 8C, this relay is provided with a main body portion 100 composed of a substantially rectangular substrate 101 and an insulating substrate 102, and is provided in the main body portion 100 to store a conductive fluid L. Stored in the storage chamber 100a, a channel 100b that communicates with the storage chamber 100a and serves as a flow path for the conductive fluid L, a pair of contacts 103 that are exposed in the channel 100b, and the storage chamber 100a. The actuator 104 is composed of a piezoelectric element that moves the conductive fluid L and switches the conduction state with the contact. Here, the conductive fluid L is made of a metal (for example, mercury) that is liquid at room temperature and normal pressure (25 ° C., 1 atm). The contact 103 is made of a plating layer using a conductive metal material (for example, solder). The upper part of the storage part 100a in FIG. 8B is a thin-film diaphragm part, which is pressed by the actuator 104 and bent downward when the actuator 104 is driven.

  The operation of this conventional example will be described below. First, in a state where no voltage is applied, the actuator 104 does not operate, so that the diaphragm portion does not deform. In this state, the conductive fluid L stored in the storage chamber 100a is in contact with only one contact 103, and the contact is opened. When the actuator 104 is driven by applying a voltage, the diaphragm 104 is bent downward by the actuator 104, the conductive fluid L stored in the storage chamber 100a is pushed out and moves in the channel 100b, and the conductive fluid L And the other contact 103 come into contact with each other. Then, since both the contacts 103 are conducted through the conductive fluid L, the contacts are closed. When the application of the voltage is stopped, the diaphragm portion deformed by the actuator 104 returns to the original state, so that the conductive fluid L also returns to the storage chamber 100a, and the contact is opened.

  As described above, since the pair of contacts are opened and closed via the liquid metal, the contacts are not welded even when an arc is generated between the liquid metal and the contacts. Further, even if the liquid metal evaporates due to the arc, the liquid metal is not consumed in order to return to the liquid again.

JP 2008-159322 A

  However, in the above conventional example, there is still a possibility that an arc is generated between the contact and the liquid metal, particularly when the gap between the contacts is opened. For this reason, there has been a problem that the contact material made of solid metal is melted and softened by the arc, so that the contact material is deformed and consumed.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid metal relay capable of preventing the generation of an arc when opening a contact.

  In order to achieve the above object, the first aspect of the present invention provides a fixed contact made of a liquid metal, a movable contact made of a solid metal that contacts and separates from the fixed contact, and the movable contact moves freely in contact with and away from the fixed contact. The movable contact is provided on the side away from the fixed contact, and is provided on the side closer to the fixed contact than the low resistance, and the low resistance is provided on the side away from the fixed contact. And a high resistance portion having a resistance value higher than that of the low resistance portion.

  The invention of claim 2 is the invention of claim 1, wherein the low resistance portion and the high resistance portion are made of materials having different resistivities, and the high resistance portion is formed of a material having different resistivities. It is characterized by being formed by laminating a plurality of layers that are laminated such that the resistance value increases from the low resistance portion side toward the fixed contact side.

  The invention of claim 3 is characterized in that, in the invention of claim 1, the high resistance portion is formed by roughening the surface of the portion made of the same material as the low resistance portion.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the high resistance portion is formed by providing a film made of a material having a higher resistivity than the material on the surface of a portion made of the same material as the low resistance portion. Features.

  The invention of claim 5 is characterized in that, in the invention of claim 4, the film is provided such that its thickness increases from the low resistance portion side toward the fixed contact side.

  According to a sixth aspect of the invention, in the first aspect of the invention, the low resistance portion and the high resistance portion are made of materials having different resistivities, respectively, and the high resistance portion has a cross-sectional area of a portion on the fixed contact side. It is characterized by being formed so as to be smaller than the cross-sectional area of other portions.

  According to a seventh aspect of the present invention, in the first aspect of the invention, the low resistance portion and the high resistance portion are both made of the same material, and the cross section of the portion on the fixed contact side of the high resistance portion is another portion. It is characterized in that it is formed so as to be smaller than the cross-sectional area.

  The invention of claim 8 is the invention of claim 6 or 7, wherein the portion of the high resistance portion on the fixed contact side is formed such that the cross-sectional area gradually decreases from the low resistance portion side toward the fixed contact side. It is characterized by that.

  The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the surface of the high resistance portion is subjected to water repellent treatment.

  According to the first aspect of the invention, when opening the contacts, the low resistance portion is first separated from the liquid metal forming the fixed contact, and then the high resistance portion is gradually exposed from the liquid metal, so that the resistance value gradually increases. And the current flowing between the contacts can be gradually limited. For this reason, it is possible to limit the current flowing before the movable contact completely leaves the fixed contact to a current value that does not generate an arc, and therefore it is possible to prevent the occurrence of an arc when opening the contacts.

  According to the invention of claim 2, since the resistance value of the high resistance portion can be increased without generating an arc when the low resistance portion leaves the liquid metal forming the fixed contact, the high resistance portion can be made of a single material. Compared with the case of configuring, the size of the high resistance portion required to limit the current flowing between the contacts to a current value that does not generate an arc can be reduced.

  According to the third aspect of the present invention, it is possible to reduce the cost required for manufacturing the movable contact as compared with the case where the high resistance portion is made of a material different from that of the low resistance portion.

  According to the fourth aspect of the present invention, the cost required for manufacturing the movable contact can be reduced as compared with the case where the high resistance portion is made of a material different from that of the low resistance portion.

  According to the invention of claim 5, since the resistance value of the high resistance portion can be increased without generating an arc when the low resistance portion is separated from the liquid metal forming the fixed contact, the high resistance portion can be made of a single material. Compared with the case of configuring, the size of the high resistance portion required to limit the current flowing between the contacts to a current value that does not generate an arc can be reduced.

  According to the sixth aspect of the present invention, the cost required for manufacturing the movable contact can be reduced as compared with the case where the high resistance portion is made of a material different from that of the low resistance portion.

  According to the seventh aspect of the present invention, the cost required for manufacturing the movable contact can be reduced as compared with the case where the high resistance portion is made of a material different from that of the low resistance portion.

  According to the invention of claim 8, since the resistance value of the high resistance portion can be increased without generating an arc when the low resistance portion leaves the liquid metal forming the fixed contact, the high resistance portion can be made of a single material. Compared with the case of configuring, the size of the high resistance portion required to limit the current flowing between the contacts to a current value that does not generate an arc can be reduced.

  According to the ninth aspect of the present invention, it is possible to prevent the liquid metal from remaining wet in the high resistance portion when opening between the contacts, so that it is possible to improve the breaking performance between the contacts.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of the liquid metal relay which concerns on this invention, (a) is a figure which shows the state in which between contacts are open, (b) is a figure in which the state between contacts is closed. is there. It is a figure which shows the other structure of a high resistance part same as the above, (a) is a figure which shows the case where the coating is provided in the surface of a high resistance part, (b) is a case where the surface of a high resistance part is roughened. FIG. It is a figure which shows the other structure of a high resistance part same as the above, (a) is a figure which shows the case where the lower end part of a high resistance part is made thinner than another site | part, (b) is a figure which shows the lower end part of a high resistance part. It is a figure which shows the case where it is made into the shape of a substantially pyramid. It is a figure which shows Embodiment 2 of the liquid metal relay which concerns on this invention. It is a figure which shows the other structure of a high resistance part same as the above. It is a figure which shows the other structure of a high resistance part same as the above, (a) is a figure which shows the case where the lower end part of a high resistance part is made thinner than another site | part, (b) is a figure which shows the lower end part of a high resistance part. It is a figure which shows the case where it is made into the shape of a substantially pyramid. Each of the conventional drawings is a diagram showing the generation of an arc when opening and closing between contacts made of solid metal, (a) is a diagram showing a case of closing between the contacts, (b) is a case of opening between the contacts. FIG. It is a figure which shows the conventional liquid metal relay, (a) is a schematic rear view, (b) is an A-A 'cross-sectional arrow view, (c) is a B-B' cross-sectional arrow view.

(Embodiment 1)
Hereinafter, a liquid metal relay according to a first embodiment of the present invention will be described with reference to the drawings. In the following description, the vertical direction in FIG. 1A is defined as the vertical direction. In this embodiment, as shown in FIGS. 1A and 1B, a fixed contact 2 made of a liquid metal, a movable contact 1 made of a solid metal that contacts and separates from the fixed contact 2, and the movable contact 1 are fixed contacts. 2 and an actuator 3 that is moved so as to be movable toward and away from 2. In addition, in this embodiment and below-mentioned Embodiment 2, only the contact structure used as the summary of this invention is explained in full detail, and illustration and description are abbreviate | omitted about the other structure of a liquid metal relay.

  The movable contact 1 is provided on the side farther from the fixed contact 2 (upper side), and has a low resistance portion 10 that is in contact with the fixed contact 2 when the contacts are closed, and a side closer to the fixed contact 2 than the low resistance portion 10 And a high resistance portion 11 having a higher resistance value than the low resistance portion 10. Here, the low resistance portion 10 and the high resistance portion 11 are made of materials having different resistivities, and the high resistance portion 11 is made of a material having a higher resistivity than the material forming the low resistance portion 10.

  The fixed contact 2 is made of, for example, a liquid metal such as mercury, gallium (Ga), indium (In), tin (Sn), or a fusion metal. It arrange | positions on the fixed electrode part 20 so that the space | interval may be provided. The fixed electrode portion 20 is made of, for example, a solid metal such as solder, and supports the fixed contact 2 and is electrically connected to the fixed contact 2.

  The actuator 3 is made of, for example, a piezoelectric element, and when a voltage is applied, the actuator 3 is driven downward to move the movable contact 1 downward so as to contact the fixed contact 2. When the voltage application is stopped in a state where the voltage is applied, the movable contact 1 is moved upward so as to move away from the fixed contact 2 by driving upward. Note that the actuator 3 is not limited to a piezoelectric element, and may have other configurations as long as the movable contact 1 can be moved to and away from the fixed contact 2.

  The operation of this embodiment will be described below. First, a case where the contacts are closed will be described. When the actuator 3 is driven downward by applying a voltage, the movable contact 1 moves downward to contact the fixed contact 2. Here, in the movable contact 1, the high resistance portion 11 first comes into contact with the fixed contact 2, but at this time, the contact is not closed. As the movable contact 1 moves downward, the high resistance portion 11 enters the fixed contact 2, and when the low resistance portion 10 comes into contact with the fixed contact 2, the movable contact 1 is fixed to the movable contact 1 via the low resistance portion 10. The contact 2 is conducted and the contact is closed.

  Next, the case of opening between the contacts will be described. When the application of the voltage to the actuator 3 is stopped, the actuator 3 is driven upward and the movable contact 1 is moved upward. Here, in the movable contact 1, the low resistance portion 10 is first separated from the fixed contact 2. And if the low resistance part 10 leaves | separates from the fixed contact 2, the high resistance part 11 will begin to be exposed to the exterior of the fixed contact 2 gradually from an upper end part next. Then, the current flowing through the fixed contact 2 via the low resistance portion 10 having a low resistance value flows to the fixed contact 2 via the high resistance portion 11 having a high resistance value, so that the current flowing between the contacts is limited. . Furthermore, since the high resistance portion 11 is gradually exposed from the fixed contact 2 as the movable contact 2 moves upward, the portion through which the current flows in the high resistance portion 11 becomes longer and the resistance value becomes higher. The current flowing between them is gradually limited. When the high resistance portion 11 reaches a time point away from the fixed contact 2, the current flowing between the contacts is sufficiently limited to a current value that does not generate an arc, so that no arc is generated when opening the contacts. .

  As described above, when opening the contacts, the low resistance portion 10 is first separated from the liquid metal forming the fixed contact 2, and then the high resistance portion 11 is gradually exposed from the liquid metal, so that the resistance value gradually increases. The current that increases and flows through the movable contact 1 can be gradually limited. For this reason, it is possible to limit the current flowing before the movable contact 1 completely leaves the fixed contact 2 to a current value that does not generate an arc, thus preventing the occurrence of an arc when opening the contacts. it can. Thus, since the fixed contact 2 made of solid metal is not melted and softened by the arc, it is possible to prevent the contact material from being deformed or consumed.

  In the above embodiment, the low resistance portion 10 and the high resistance portion 11 are formed of materials having different resistivities, but the movable contact 1 is formed of the same material and the lower end portion of the movable contact 1. Alternatively, the high resistance portion 11 may be configured by processing so that the resistance value is different from that of the low resistance portion 10. For example, as shown in FIG. 2A, the high resistance portion 11 is configured by providing a film 4 made of a material having a higher resistivity than the material constituting the movable contact 1 on the surface of the lower end portion of the movable contact 1. May be. Further, as shown in FIG. 2 (b), the resistance value of the roughened portion is reduced to the resistance value of the low resistance portion 10 by roughening the surface of the lower end portion of the movable contact 1 by providing fine irregularities. The high resistance portion 11 may be configured to be higher than that. That is, by roughening the surface of the movable contact 1, the wettability of the liquid metal forming the fixed contact 2 with respect to the solid metal forming the movable contact 1 is reduced, and air is formed between the liquid metal and the solid metal in each recess. By interposing, the contact area between the liquid metal and the solid metal can be reduced, and as a result, the resistance value of the high resistance portion 11 can be made higher than that of the low resistance portion 10.

  Further, as shown in FIG. 3A, the resistance value of the portion where the cross-sectional area is reduced is reduced by making the cross-sectional area of the lower end of the movable contact 1 smaller than the cross-sectional area of the low-resistance part 10. The high resistance portion 11 may be configured to be higher than the resistance value. Further, as shown in FIG. 3B, the lower end portion of the movable contact 1 is formed in a sharp shape such as a substantially pyramid shape, that is, the cross-sectional area is increased from the low resistance portion 10 side toward the fixed contact 2 side. The high resistance portion 11 may be formed by forming so as to gradually decrease. In any of the above cases, the same effect as in the above embodiment can be obtained. Moreover, compared with the case where the high resistance part 11 is comprised with a material different from the low resistance part 10, the cost required when manufacturing the movable contact 1 can be reduced.

(Embodiment 2)
Hereinafter, a liquid metal relay according to a second embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of the present embodiment is the same as that of the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, as shown in FIG. 4, the high resistance portion 11 is formed by laminating a plurality of layers formed of materials having different resistivities from each other, and from the low resistance portion 10 side to the fixed contact 2 side. It is laminated so that the resistance value increases as it goes.

  Here, in the first embodiment, the current flowing between the contacts is gradually limited by providing the high resistance portion 11, but in order to limit the current value to such an extent that no arc is generated, the high resistance portion 11 is used. The length dimension of the up and down direction must be increased. For this reason, it is conceivable to form the high resistance portion 11 with a material having a higher resistivity. However, if the resistance value of the high resistance portion 11 is set higher than the resistance value of the low resistance portion 10, an arc may be generated when the low resistance portion 10 leaves the fixed contact 2 when opening the contacts. is there. That is, in order to open the contacts so that no arc is generated, it is necessary to prevent the current flowing between the contacts from being suddenly limited when the low resistance portion 10 is separated from the fixed contact 2.

  Therefore, in the present embodiment, the high resistance portion 11 is formed so that the resistance value becomes higher from the low resistance portion 10 side toward the fixed contact 2 side. Therefore, when opening between the contacts, the low resistance portion 10 is formed. An arc does not occur at the time of moving away from the fixed contact 2, and the current flowing between the contacts can be efficiently limited. For example, if the layer in contact with the low resistance portion 10 of the high resistance portion 11 is formed of the same material as that of the high resistance portion 11 of the first embodiment, the resistance value is compared to the case where the high resistance portion 11 is formed of a single material. Therefore, it is possible to reduce the length in the vertical direction of the high resistance portion 11 necessary for current limiting to a current value that does not generate an arc.

  As shown in FIG. 5, the movable contact 1 is formed of the same material, and a coating 4 made of a material having a higher resistivity than the material constituting the movable contact 1 is formed on the surface of the lower end portion of the movable contact 1. The high resistance portion 11 may be provided, and the thickness of the coating 4 may be increased from the low resistance portion 10 side toward the fixed contact 2 side. In this case, since the resistance value of the high resistance portion 11 increases as the film 4 becomes thicker, the same effect as in the above embodiment can be obtained.

  Further, as shown in FIG. 6A, one end on the low resistance portion 10 side in the high resistance portion 11 is formed with the same cross-sectional area as that of the low resistance portion 10, and the other end on the fixed contact 2 side is formed on the low resistance portion 10. The cross-sectional area may be smaller than the cross-sectional area. In this case, since the resistance value is different between the portion having a large cross-sectional area and the portion having a small cross-sectional area, the resistance value of the high resistance portion 11 is increased in order, and the same effect as in the above embodiment can be obtained. Further, as shown in FIG. 6B, the high resistance portion 11 is formed in a sharp shape such as a substantially pyramid shape, that is, the cross-sectional area gradually increases from the low resistance portion 10 side toward the fixed contact 2 side. You may form so that it may become small. In this case, since the resistance value increases as the cross-sectional area decreases, the same effect as in the above embodiment can be obtained.

  6 (a) and 6 (b), the low resistance portion 10 and the high resistance portion 11 are made of materials having different resistivities, but the same material may be used. In this case, compared with the case where the high resistance part 11 is comprised with a material different from the low resistance part 10, the cost required when manufacturing the movable contact 1 can be reduced.

  By the way, when opening between contacts, when the high resistance part 11 is gradually exposed from the fixed contact 2, the liquid metal which comprises the fixed contact 2 may remain on the surface of the high resistance part 11. In this case, the low resistance portion 10 and the fixed contact 2 are conducted through the liquid metal remaining wet, and the current flowing between the contacts cannot be limited, so that the interruption performance is deteriorated.

  Therefore, in both the first and second embodiments, it is desirable to perform the water repellent treatment on the high resistance portion 11. As the water repellent treatment, for example, as already described in the first embodiment, the surface of the high resistance portion 11 is roughened to reduce the wettability of the liquid metal to the solid metal, or the surface of the high resistance portion 11 is treated with fluorine. There is a method of reducing wettability between the liquid metal and the film 4 by providing a system-based or silicon-based film 4. By performing the water-repellent treatment in this way, it is possible to prevent the liquid metal from remaining wet in the high resistance portion 11 when opening the contacts, so that the blocking performance between the contacts can be improved.

DESCRIPTION OF SYMBOLS 1 Movable contact 10 Low resistance part 11 High resistance part 2 Fixed contact 3 Actuator (drive means)

Claims (9)

  A fixed contact made of a liquid metal, a movable contact made of a solid metal that contacts and separates from the fixed contact, and a driving means that moves the movable contact to and away from the fixed contact. The movable contact is separated from the fixed contact. A low-resistance portion that is provided on the other side and that is in contact with the fixed contact when the contact is closed, and a high-resistance portion that is provided closer to the fixed contact than the low-resistance portion and has a higher resistance value than the low-resistance portion A liquid metal relay characterized by comprising:   The low resistance portion and the high resistance portion are each made of a material having a different resistivity, and the high resistance portion is made by laminating a plurality of layers each made of a material having a different resistivity. The liquid metal relay according to claim 1, wherein the liquid metal relay is laminated so that a resistance value increases from a part side toward a fixed contact side.   2. The liquid metal relay according to claim 1, wherein the high resistance portion is formed by roughening the surface of a portion made of the same material as that of the low resistance portion.   2. The liquid metal relay according to claim 1, wherein the high resistance portion is provided with a coating made of a material having a higher resistivity than the material on a surface of a portion made of the same material as the low resistance portion.   5. The liquid metal relay according to claim 4, wherein the thickness of the coating is increased so as to increase in thickness from the low resistance portion side toward the fixed contact side.   The low resistance portion and the high resistance portion are made of materials having different resistivities, respectively, and the high resistance portion is formed such that the cross-sectional area of the portion on the fixed contact side is smaller than the cross-sectional area of other portions. The liquid metal relay according to claim 1, wherein   The low resistance part and the high resistance part are both made of the same material, and the high resistance part is formed so that the cross-sectional area of the part on the fixed contact side is smaller than the cross-sectional area of the other part. The liquid metal relay according to claim 1.   8. The liquid metal relay according to claim 6, wherein a portion of the high resistance portion on the fixed contact side is formed so that a cross-sectional area gradually decreases from the low resistance portion side toward the fixed contact side. .   The liquid metal relay according to any one of claims 1 to 8, wherein a surface of the high resistance portion is subjected to a water repellent treatment.

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