WO2008010410A1

WO2008010410A1 - Spd with disconnection function and manufacturing method thereof

Info

Publication number: WO2008010410A1
Application number: PCT/JP2007/063273
Authority: WO
Inventors: Kenshichirou Mishima; Tsuyoshi Ikeda; Takeshi Maruyama; Kenji Kimoto
Original assignee: Otowa Electric Co., Ltd.
Priority date: 2006-07-20
Filing date: 2007-07-03
Publication date: 2008-01-24
Also published as: JP2008028089A; JP5020560B2

Abstract

This invention provides a highly reliable SPD with a disconnection function which can realize reliable thermal fuse operation upon abnormal heat generation due to a deterioration in a zinc oxide varistor. A bent spring part (13c) is formed in a disconnection conductor (13) connected to an electrode (11) of a zinc oxide varistor (1) with the aid of a low melting temperature alloy (14), and the spring part (13c) is housed in a case (30) containing all of the above elements, followed by positioning. In this case, the varistor (1) is rotated in the case (30) to bend the spring part (13c) of the disconnection conductor (13) in a predetermined direction, so that spring forces in two different directions are applied to the spring part (13c) by the displacement due to the bend of the spring part (13c). When the low melting temperature alloy (14) is melted by the abnormal heat generation in the varistor (1), the disconnection conductor (13) is separated from the electrode (11) of the varistor (1) by utilizing the spring forces in two directions of the spring part (13c).

Description

Specification

SPD with separation mechanism and manufacturing method

Technical field

[0001] The present invention relates to an SPD (Surge Protective Device) with a detachment mechanism in which a release conductor, which is a protection means against deterioration of an acid-zinc-type varistor and its NORISTA, is housed in a case.

Background art

[0002] For the purpose of preventing lightning damage, SPD is installed as a device that shunts surge current by limiting transient overvoltage caused by lightning between electrical equipment and the ground in single-phase or three-phase AC circuit or DC circuit Has been. As this SPD element, an acid-zinc type varistor is generally used.

[0003] A zinc oxide type varistor (hereinafter simply referred to as a varistor) is a rectangular or circular plate-shaped lightning protection element mainly composed of ZnO, and electrodes are attached in a thin plate shape on both the front and back surfaces. The varistor has a characteristic that the resistance changes according to the voltage applied between the electrodes on both the front and back sides, that is, it exhibits extremely high resistance and substantial insulation when a voltage lower than the threshold voltage is applied. When a voltage exceeding is applied, it has a nonlinear current-voltage characteristic that exhibits low resistance.

[0004] In addition, SPDs that use NORISTA are housed in insulating cases made of resin by assembling other SPD elements such as discharge gaps, thermal fuses for SPD protection, and current fuses. This structure is common. The case electrically and mechanically protects multiple SPD elements including NORISTAR. A thermal fuse is an SPD element that protects against degradation of the NORISTOR. When a lightning surge is repeatedly input, the NORISTOR may deteriorate over time depending on the input level, the leakage current increases and heat is generated, which may cause smoke and fire due to thermal runaway. Therefore, in SPD, as a protective measure to prevent smoke and fire due to thermal runaway of the varistor, a temperature fuse that operates by disconnection due to heat generation due to varistor degradation is integrated into the NORISTR (see, for example, Patent Document 1). .

Patent Document 1: Japanese Patent Laid-Open No. 2003-229303 Disclosure of the invention

Problems to be solved by the invention

[0005] In the SPD disclosed in Patent Document 1 described above, the external terminal is joined to the electrode of the parisher with a low melting temperature alloy (easily fusible metal or conductive low melting substance) that melts due to abnormal heat generation due to varistor degradation. Thus, the temperature fuse portion is configured. In this case, the thermal fuse is located close to the varistor compared to a structure in which the thermal fuse is attached as a separate part to the NORISTA. Because the low melting temperature alloy melts quickly, the thermal fuse operates with high sensitivity.

[0006] However, depending on the surrounding conditions of the low melting temperature alloy that joins the electrode of the varistor and the external terminal, the movement or diffusion when the low melting temperature alloy is melted becomes insufficient, and the electrode between the varistor electrode and the external terminal is insufficient. There is a possibility that it may be difficult to electrically isolate the gap, and there is a problem in reliability of temperature fuse operation.

[0007] The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an SPD with a separation mechanism having a highly reliable temperature fuse function. Means for solving the problem

In order to achieve the above object, the present invention provides a varistor and a spring force that is bonded to the varistor electrode with a low melting temperature alloy and is separated from the varistor electrode when the low melting temperature alloy melts due to abnormal heat generation of the NORISTA. The SPD is provided with a separating conductor and a case for positioning and holding the varistor and the separating conductor, and the separating conductor is connected to the electrode of the NORISTR and one end of the connection And a bent spring part, and a fixed part that extends from this spring part and is positioned and held in the case. The case has a spring part of the separating conductor when storing the varistor to which the separating conductor is connected. It is characterized by having positioning means for positioning and holding the varistor in a state in which the spring is imparted by displacing.

Here, the varistor is a lightning protection element having a rectangular flat plate shape or a disk shape, and has, for example, silver-baked or aluminum sprayed electrodes on the front and back surfaces, and a selected conductor is connected to a conductor separated by a low melting temperature alloy. The The case is an insulating case made of resin, which houses the SPD element including the varistor and protects the SPD element by insulation. SPD elements other than NORISTA have a discharge gap and temperature resistance. Use, current fuse, etc. The disconnecting conductor connected to the electrode of the NORISTA can be a wire having a spring property, a plate, or a combination of a wire and a plate. One end (connecting part) of the disconnecting conductor is joined to the varistor electrode with a low melting temperature alloy (such as low melting cream solder), and the other end (fixing part) is positioned and held on the case. Is provided with a spring part having springiness. The spring portion of the separated conductor has a spring property by being bent. The spring part of the separation conductor has a spring force that separates the connection part from the electrode of the varistor by melting the low melting temperature alloy due to abnormal heat generation of the varistor. When the varistor unit connected to the disconnecting conductor is housed in the case, the positioning means provided on the case displaces the varistor and holds it in place. It is bent to have a predetermined spring property. By doing so, the spring portion of the separating conductor can be easily and reliably provided with a spring property, and the temperature fuse operation by melting the low melting temperature alloy can be ensured. As the case positioning means, protrusions, stepped portions, and engagement holes that are pressed against the periphery of the NORISTAR without electrodes can be applied.

[0010] In the present invention, the spring portion of the disconnecting conductor includes the first spring force generating portion and the connecting portion for disconnecting the connecting portion of the disconnecting conductor in parallel with the electrode force of the varistor when the low melting temperature alloy is melted. A structure having a second spring force generating portion that separates the electrode force of the varistor by rotating the fixing portion of the separating conductor as a base point through the one spring force generating portion.

[0011] Here, the first spring force generation portion and the second spring force generation portion are continuous bent portions, and the first spring force generation portion extends from the connection portion of the disconnected conductor, and from the first spring force generation portion. The second spring force generation portion extends, and further, the fixed portion extends from the second spring force generation portion to form a single separated conductor. The first spring force generation part and the second spring force generation part are made to have different bending directions so that the first spring force generation part has a spring property so that the electrode force connection part of the varistor is separated in a translational manner. The spring force generating part is provided with spring characteristics so that the electrode force connecting part of the varistor is separated so as to rotate and swing. As the bent shape of each spring force generating portion having such a spring property, a curved shape, a linear shape, a spiral shape, or a combination of these shapes can be applied. The electrode force of the NORISTOR is also disconnected, and the connection part of the conductor is disconnected simultaneously by two different forms of parallel movement and rotational oscillation, ensuring a large separation distance. The reliability of the thermal fuse operation is improved. In addition, the spring force of the first spring force generation part and the second spring force generation part is small, and a thin wire or thin plate can be applied to the separating conductor.

[0012] In the present invention, the disconnecting conductor can be constituted by either a wire or a plate. The separating conductor of the wire becomes easy to configure the spring part in a semicircular arc shape or a spiral shape. In addition, the cut-off conductor of the plate material can be easily designed to have various spring properties by complicating the shape of the spring portion.

[0013] Further, in the present invention, in the case, a space portion that allows disengagement by the restoring spring force of the disconnection conductor connecting portion and the spring portion force when the low melting temperature alloy is melted may be formed. desirable. In this way, even if the case is a sealed case, the SPD element including the conductor separated from the NORISTA can also be protected by shielding the external force of the case, which is undesirable for the spring part of the disconnected conductor. Thermal fuse operation can be reliably performed without external force.

In the present invention, as the case, a split type case having at least a first case and a second case that are positioned and held with a noristor interposed therebetween can be applied. If the first case of this case is a first case with a lid with a bottom that accommodates the varistor unit, the second case can be a lid of the first case with a lid. Also, one or both of the first case and the second case can be divided into two divided cases, and the case can be divided into three or more divided cases. By dividing the case in this way, the work of inserting the NORISTA unit and the work of positioning with the varistor in between become easy, and the spring part of the disconnected conductor has a predetermined spring property. Becomes easier.

[0015] Further, in the present invention, the abnormality of the varistor is caused by a mechanical or electrical change in the case where the connection portion of the disconnecting conductor is disconnected in the case when the low melting temperature alloy melts the electrode force of the varistor. In addition to providing a display that displays heat generation, the case can be provided with a display window in which the display state of the display can be seen by the external case. In this case, abnormal heat generation due to varistor degradation can be easily recognized by visually observing the display from the display window of the case even if the noristor and the separated conductor are housed in the case. The display here can be a mechanical type of color-coded display board or an electric type such as a light-emitting diode. Is applicable. It is desirable to fix the former mechanical indicator on the connection side of the disconnecting conductor that mechanically displaces when the electrode force of the NORISTR is also disconnected. In addition, the latter electric indicator lights up (or goes off) when the electrical connection between the varistor electrode and the disconnecting conductor is normal, and the disconnecting conductor connecting part is disconnected from the varistor electrode and electrically connected. A light-emitting diode that turns off (or turns on) when the light is cut off may be attached to the varistor.

[0016] In the present invention, the varistor is a multi-terminal varistor having a plurality of electrodes connected to the line phase of the AC circuit on the front surface side and a common electrode for the ground phase on the back surface side. Separate conductors and indicators can be installed on each of the corresponding electrodes. As the varistor here, a single-phase or three-phase three-wire AC circuit acid-zinc zinc lightning protection element can be applied. Three electrodes connected to the three-wire line phase of the three-wire AC circuit are formed separately on the surface of a single varistor, and the common electrode of the earth phase corresponding to the deviation of the three electrodes of the line phase is formed on the back of the noristor. Once formed, a set of disconnected conductors and indicators are installed on each of the three electrodes. Display windows are formed at three locations on the case in correspondence with the three-electrode displays. In this way, even if the varistor corresponding to the three-wire line phase of the three-wire AC circuit!

[0017] In the present invention, the connecting portion between the NORISTR and the disconnecting conductor is coated with an insulating coating material that is solid at normal temperature and is in a gel or liquid state below the melting temperature of the low melting temperature alloy. Can do. The insulating coating material here is preferably a wax that becomes liquid at a temperature lower than the melting temperature of the low melting temperature alloy, or a solvent-based coating material that softens at a temperature lower than the melting temperature of the low melting temperature alloy.

[0018] By storing the unit in which the connection portion of the varistor and the separating conductor is covered with the insulating coating material in this way, the NORISTA unit is double-insulated and protected by the insulating coating material and the case. Increased reliability. In addition, when the varistor deteriorates, the insulation coating becomes a gel or liquid before the low melting temperature alloy melts, and enters between the noristor electrode and the disconnected conductor connection, and each is covered with the insulation. In addition, the electrical and mechanical disconnection between the varistor and the disconnecting conductor is ensured, and the reliability of the thermal fuse is further increased. When wax is used for the insulation coating material, the wax that is in liquid form is Then, it is applied to the main part including the separated conductor and dried at room temperature to form a solid. In addition, when the insulation coating material is a solvent-based coating material, it is in a liquid state at room temperature, so it is applied to the main parts including the varistor and the separated conductor, dried at room temperature, and the solvent is blown to form a solid. . All of them need only be applied and dried, so it is easy.

[0019] In addition, the SPD manufacturing method of the present invention is a connection in which an electrode lead conductor is connected to an electrode corresponding to the earth phase of a varistor having a plurality of electrodes of a line phase and an earth phase with a high melting point solder of 200 ° C or higher. And after this connection process, the electrode corresponding to the line phase of the varistor is joined with a low melting temperature alloy with a melting point above room temperature and below 200 ° C. It has the connection process which connects the isolation | separation conductor which has the spring force isolate | separated from an electrode. By manufacturing in this way, it becomes easy to connect the electrode corresponding to the line phase of the NORISTA and the disconnecting conductor in a stable state with a low melting temperature alloy, and the reliability of manufacturing and assembly of the SPD with the disconnecting mechanism is improved. Become.

[0020] Further, in the method of the present invention, the varistor connection portion by the low melting temperature alloy of the above two connection steps and the varistor and the disconnecting conductor is solid at normal temperature and at a temperature below the melting point of the low melting temperature alloy. It has a coating process of coating with an insulating coating material that is in the form of gel or liquid. Manufacturing in this way facilitates the coating operation of the insulation coating material.

[0021] According to the present invention, the spring property of the disconnected conductor that is bonded to the electrode of the noristor with a low-melting temperature alloy and exhibits a thermal fuse function can be obtained, and the spring portion of the disconnected conductor is accommodated when the varistor is housed in the case. Because it is set by displacing the wire, the spring part of the disconnected conductor can be easily and reliably provided with spring properties, and the excellent effect of improving the reliability of thermal fuse operation by the disconnected conductor Can be played.

[0022] In addition, the spring portion of the disconnecting conductor is rotated with the first spring force generating portion that disconnects the connecting portion of the disconnecting conductor movably in parallel with the electrode force of the varistor and the fixing portion of the disconnecting conductor as a base point. It consists of a second spring force generation part that separates from the electrode force, and the connection part of the conductor that separates from the electrode force of the noristor is separated in two parallel and rotationally oscillating forms. Therefore, when the thermal fuse is activated, the varistor electrode force makes it easy to separate the conductor at a large distance, and this separation can be performed with a small spring force, making the temperature fuse operation more reliable. Get better. In other words, the tip of the separation conductor is easy to see as a large displacement and easy to see, and by providing a parallel displacement portion such as a connection portion, it is easy to ensure the reliability of the separation.

BEST MODE FOR CARRYING OUT THE INVENTION

1 to 13 show an SPD with a detachment mechanism according to a first embodiment of the present invention. Fig. 1 and Fig. 2 show the main part configuration of the SPD with detachment mechanism, and Fig. 3 and Fig. 4 show the main part configuration during assembly. The SPD with a detachment mechanism shown in Figs. 1 to 4 shares two types of SPD elements: a NORISTOR 1 mainly composed of ZnO and a discharge gap 2 connected to the electrode 12 on the back side of the varistor 1. In case 30. As shown in the perspective view of FIG. 5, NORISTAR 1 is a rectangular plate-shaped lightning protection element that is applied to a single-phase three-wire or three-phase three-wire AC circuit. A common electrode 12 for the earth phase is formed. As shown in the equivalent circuit of FIG. 8, the common electrode 12 faces all of the three electrodes 11 on the surface side. The shape of the noristor 1 is not limited to a rectangular shape, and may be a disc shape.

[0024] A single conductor is separated from each of the three electrodes 11 of the line phase of the NORISTA 1 and a conductor 13 is connected by a low melting temperature alloy 14. Low melting temperature alloy 14 is a solder with melting point above normal temperature and below 200 ° C and melts due to abnormal heat generation of varistor 1. Prior to the connection of the disconnecting conductor 13 by the low melting temperature alloy 14, the electrode lead conductor 15, which is the lead wire of the discharge gap 2, is connected to the common electrode 12 of the earth phase by the high melting point solder 16. The high melting point solder 16 is a cream solder having a melting point of 200 ° C. or higher. By setting the connection process using cream solder having a high melting point before the connection process using cream solder having a low melting point, the connection process using a cream solder having a low melting point can be easily performed under stable conditions.

[0025] As the disconnecting conductor 13, a wire or plate having a spring property is applied, and in the drawing, a wire of a bare electric wire is shown. Case 30 is a rectangular box-shaped insulation case made of resin, and a total of four parallel external terminals 20 are led out from the front. Each of the four external terminals 20 is, for example, a lead wire of an insulation coated electric wire. One external terminal 20 is connected to each of the three disconnected conductors 13 connected to the three electrodes 11 of the NORISTOR 1, and the other lead wire 17 of the discharge gap 2 remains, and one external terminal 20 Connected to.

[0026] The case 30 is a rectangular box-shaped upper and lower divided case, and includes a first case (case main body) 30a having a bottomed upper end opening and a second case (case lid) 30b that closes the upper end opening of the first case 30a. . The first case 30a includes a terminal holding portion 30c on the bottom of which the four external terminals 20 can be removed. The front case side force of the first case 30a also includes four parallel external terminals 20 inserted into the terminal holding portion 30c, and each of the four inserted external terminals 20 has three disconnecting conductors 13 and a discharge gap of two forces. The lead wire 17 is electrically and mechanically connected by a plug-in type or a caulking type.

[0027] The case 30 positions and stores a Paristat 40 in which the discharge gap 2 and the disconnecting conductor 13 are connected to the noristor 1. As shown in FIGS. 5 and 6, the noristor unit 40 is a unit component in which three release conductors 13 and one discharge gap 2 are connected to the varistor 1. A single display 50 is detachably attached to each separating conductor 13 of the varistor unit 40. As shown in FIG. 10, the display device 50 is a resin molded product including a mounting portion 50a that is removably inserted and fixed to the distal end portion of the separating conductor 13, and a display plate 50b integrated with the mounting portion 50a. It is. The front face of the display board 50b is divided into two parts, the upper part of the front face is divided into, for example, a blue part B displaying normal varistors, and the lower part of the front face is divided into red parts R displaying varistor degradation.

[0028] The first case 30a and the second case 30b of the case 30 have positioning means 31, 32 for holding the NORISTR 1 of the NORISTOR unit 40 from above and below. The first case 30a has cylindrical positioning means 33 for positioning and holding the three separating conductors 13 of the NORISTR unit 40 one by one on the terminal holding portion 30c at the bottom. The positioning means 31 of the first case 30a is a plurality of projecting pieces that position and hold the flat NORISTOR 1 of the varistor unit 40 in parallel with the bottom surface of the first case 30a. Projected on the inner surface of the wall. The positioning means 32 of the second case 30b is a plurality of projecting pieces whose downward opening force of the second case 30b also projects downward, and is projected on the inner surfaces of both side walls of the second case 30b. As shown in FIGS. 3 and 4, the second case 30b has a positioning means 34 for positioning the cases relative to each other when covering the first case 30a, and a handle for facilitating the handling of the case. 35 is integrated. The dimensional relationship between the positioning means 31 and 32 of both cases 30a and 30b and the operation procedure of varistor positioning will be described later. In addition, the case 30 has display windows 51 at three positions facing the display 50 connected to the three separating conductors 13 of the stored varistor unit 40. The display window 51 shown in FIG. 2 is a rectangular hole in which a notch formed at the upper end of the opening of the first case 30a and a notch formed at the lower end of the opening of the second case 30b are combined. Such a display window 51 may be covered with a transparent plate or transparent filler having a lens function.

[0030] Each of the three disconnected conductors 13 connected to the three electrodes 11 that are the line phase of the NORISTR 1 has the following configuration and a thermal fuse function. Fig. 5 shows the disconnected conductor 13 in a state without springiness. The disconnected conductor 13 includes a connecting portion 13a connected to the electrode 11 of the varistor 1 with a low melting temperature alloy 14, a display mounting portion 13b extending integrally from the tip of the connecting portion 13a, and a rear portion of the connecting portion 13a. The end portion also has a spring portion 13c that is bent by extending integrally, and a fixing portion 13d that extends integrally from the end opposite to the connection portion 13a of the spring portion 13. The connecting portion 13a is a straight portion along the electrode 11 of the varistor 1. The display attachment portion 13b is an L-shaped wire that rises from the connection portion 13a and extends forward, and the attachment portion 50a of the display device 50 is inserted and fixed to the open front end portion. The spring portion 13c has a different bi-directional spring property by bending with the displacement of the noristor 1 when the NORISTA unit 40 is inserted into the case 30.

[0031] Specifically, the spring portion 13c is bent at a first spring force generating portion 13p that bends in a semicircular arc shape in a plane parallel to the surface of the flat varistor 1, and at a vertical plane orthogonal to the surface of the varistor 1. A second spring force generator 13q is provided. A first spring force generating portion 13p and a second spring force generating portion 13q extend continuously from the connecting portion 13a, and a fixing portion 13d extends from the tip of the second spring force generating portion 13q. The fixing portion 13d is a portion that is finally fixed in the case 30, and is fitted and fixed to the cylindrical positioning means 33 of the first case 30a as shown in FIG. The distal end of the fixing portion 13d is electrically and mechanically connected to the external terminal 20 inserted into the terminal holding portion 30c at the bottom of the first case 30a.

Next, the assembly procedure and thermal fuse operation procedure of the SPD with the disconnecting function of the above embodiment will be described with reference to FIGS.

FIG. 3 and FIG. 4 show an operation procedure when the varistor unit 40 is housed in the case 30. The disconnected conductor 13 of the NORISTR unit 40 before being housed in the case 30 is in an open state, and the spring portion 13c maintains the original bent state. Move the NORISTA unit 40 directly above the first case 30a. The fixed part 13d of the three separating conductors 13 and one lead wire 17 of the discharge gap 2 are arranged below the varistor 1 that is moved and tilted. The varistor unit 40 is moved down into the first case 30a as it is, and the fixing portion 13d of the three separating conductors 13 and the lower end portion of one lead wire 17 are inserted into the corresponding positioning means 33 of the first case 30a. (The state in Figure 4). This multiple insertion is not shown in the figure! If you use a jig, it can be done in a short time.

FIG. 4 shows a state in which the fixing portions 13d of the three separating conductors 13 and the lower ends of one lead wire 17 are inserted into the corresponding positioning means 33 of the first case 30a. The fixing portion 13d is inserted into the corresponding positioning means 33 by a predetermined length and finally fixed as it is. At this time, as shown in the schematic diagram of FIG. 9A, the varistor 1 is positioned on the positioning means 31 on the right side of the positioning means 31 on the left and right sides in FIG. 9 of the first case 30a. It is in the same tilted state. Further, the spring portion 13c of the separating conductor 13 extending from the noristor 1 remains in the same bent state as in FIG.

In the state shown in FIG. 4, the first case 30a is covered with the second case 30b. In FIG. 4 of the second case 30b, the positioning means 34 at both left and right ends are locked to the inner wall surface of the upper end of the opening of the first case 30a. Press the edges of both ends of the tilted varistor 1 in the case 30a. Then, as shown in FIG. 9 (B), the tilted varistor 1 is rotated leftward about the right positioning means 31 in FIG. 9 by pushing the positioning means 32 of the second case 30b, and in FIG. The rotation stops when it comes into contact with the left positioning means 31 '. At the time of this rotation stop, the first case 30a and the second case 30b are merged, and the positioning means 31 and 32 of both cases sandwich the varistor 1 from above and below to a fixed position parallel to the bottom of the case. Hold the positioning.

[0036] When the tilted varistor 1 shown in Fig. 9 (A) is rotated so as to correct the tilt as shown in Fig. 9 (B), the displacement of the varistor 1 causes the spring parts 13c of the three separating conductors 13 to move. However, it bends as follows. Since each separation conductor 13 is in a state where the fixing portion 13d is inserted and fixed to the positioning means 33 of the first case 30a, it is inclined with respect to the first case 30a, and the varistor 1 is in a direction to correct the inclination. When it rotates, the connecting portion 13a is displaced integrally with this rotation, and the spring portion 13c between the connecting portion 13a and the fixing portion 13d is bent so as to follow the displacement of the connecting portion 13a. One first spring force generating portion 13p of the spring portion 13c has a semicircular arc shape in a plane parallel to the surface of the varistor 1. Due to the bent shape, the varistor 1 is bent and deformed so that the semi-arc-shaped bent portion is twisted, and has a spring force in a direction to move the connecting portion 13a away from the varistor electrode 11 in a translational manner. The other second spring force generating portion 13q of the spring portion 13c is bent in a vertical direction perpendicular to the surface of the varistor 1, and extends downward from the varistor 1 on the side of the varistor 1. The base is bent and deformed in the rotation direction of the varistor 1, and has a spring force that restores 180 ° in the direction opposite to the rotation direction. Thus, the three separated conductors 13 are housed in the case 30 together with the noristor 1 in a state where the spring portions 13c are bent and deformed.

[0037] Assembling of the case 30 is completed by integrating the first case 30a and the second case 30b with an adhesive tape or the like. The discharge gap 2 of the NORISTA unit 40 stored in the case 30 is positioned and stored in the space between the NORISTAR 1 and the bottom of the first case 30a. The fixed part 13d of the three disconnecting conductors 13 of the NORISTA unit 40 and the lead wire 17 of the discharge gap 2 are finally connected to the corresponding external terminals 20 as shown in FIG. Unnecessary parts protruding from 30 are removed by cutting. In addition, between the NORISTOR 1 of the varistor 40 housed in the case 30 and the top surface of the second case 30b, the thermal fuse operation of the three disconnecting conductors 13 and the display 50 is allowed. A sufficient space m is formed. The temperature fuse operation described later is reliably performed in this space m. In addition, each indicator 50 of the three separating conductors 13 of the NORISTR unit 40 is disposed at a fixed position facing the three display windows 51 of the case 30. At this time, the blue portion B of the display plate 50 b of the display device 50 faces the display window 51. By visually observing the blue part B from the display window 51, it is confirmed that NORISTOR 1 is normal.

[0038] Fig. 12 shows the case where the SPD with disconnection function has been activated by the thermal fuse due to abnormal heat generation due to deterioration of the varistor 1. In the line phase three electrode 11 of the NORISTR 1! /, The lightning protection element in any part deteriorates and abnormal heat is generated, and the low melting temperature alloy 14 of the separating conductor 13 in the heat generating part melts. At the time of softening before the low melting temperature alloy 14 is completely melted, the spring part 13c of the disconnecting conductor 13 is restored by the spring force, pulling the connection part 13a away from the electrode 11 and interrupting the electric circuit (temperature fuse operation). ). As a result, this blocking is performed with a sufficient separation distance as shown in Fig. 10 (A). That is, the spring portion 13c includes a first spring force generating portion 13p and a second spring force generating portion 13q that have different restoring directions due to the spring force. what if, As shown by the broken line in FIG. 10 (B), if the second spring force generating portion 13q is held without being restored, only the first spring force generating portion 13p connects the connecting portion 13a to the corresponding electrode 11. It restores with its own spring force so that it moves apart. If the first spring force generator 13p is held so as not to be restored, as shown by the broken line in FIG. 10C, only the second spring force generator 13q rotates around the fixed portion 13d. It is restored by its own spring force so that the connecting portion 13a is rotated away from the corresponding electrode 11 via the first spring force generating portion 13p. In the separation movement with only rotation shown in Fig. 10 (C), there may be a problem that the lower end of the connection part 13a is not separated from the electrode 11 by a sufficient distance. It is solved by adding the separation distance by translation of 1 0 (B). In other words, the actual thermal fuse operation in Fig. 10 (A) is a combination of the parallel movement operation in Fig. 10 (B) and the rotation operation in Fig. 10 (C), and the connecting portion 13a is sufficient from the corresponding electrode 11. Separated by distance, the temperature fuse operation is always stable and reliable.

[0039] FIG. 10 (A) is a restoring part in which the spring force of the first spring force generating portion 13p and the second spring force generating portion 13q of the spring portion 13c that makes the temperature fuse operation with high reliability is small. Even if the separation distance by the force is small, the temperature fuse operation is performed at the distance obtained by adding the separation distances. Therefore, a thin and thin wire can be applied to the entire separation conductor 13, and a small case can be applied to the case 30. Further, the indicator 50 at the tip of the separating conductor 13 moves the largest distance during the thermal fuse operation. With this movement, the blue portion B of the display device 50 is hidden from the display window 51, and instead, the red portion R moves to the display window 51 and is visually recognized from the outside. Since the moving amount of the display device 50 is large, the normal / deteriorating display operation of the NORISTAR is performed accurately and reliably.

[0040] The thermal fuse operation is performed independently due to the deterioration of the NORISTOR of any of the three electrodes 11 of NORISTOR 1. In addition, since the low melting temperature alloy 14 constituting the thermal fuse is joined to the varistor electrode 11 and integrated, the internal temperature of the NORISTOR 1 can be transmitted to the low melting temperature alloy 14 most efficiently. . Therefore, the melting point of the low melting temperature alloy 14 which is the set temperature of the thermal fuse can be set sufficiently higher than the normal temperature, and for example, it can be composed of an alloy having a melting point of about 150 ° C. Such a low melting temperature alloy 14 is preferably a cream solder having a composition of Bisma Suzuka. Also, low melting temperature alloy 14 For example, when it is composed of cream solder with a composition consisting of bismuth and tin that melts at 138 ° C, the temperature at the time of joining and breaking operation that melts the low melting temperature alloy 14 will be about 150 ° C, so the separated conductor If the material of 13 is phosphor bronze, the springiness may be lost. For this reason, the material of the separating conductor 13 is preferably beryllium copper that does not lose its spring property even at 160 ° C.

Next, an SPD with a separation function according to the second embodiment shown in FIGS. 13 to 15 will be described. In this SPD, the varistor 1 and its peripheral part in the NORISTA unit 40 are covered with an insulating coating material 60. The other components except the insulating covering 60 are the same as the SPD in FIG.

[0042] The insulating coating material 60 is an insulating material that is solid at room temperature and becomes gel or liquid at a temperature equal to or lower than the melting temperature of the low melting temperature alloy 14. As this insulating coating material 60, a wax which becomes liquid at a temperature lower than the melting temperature of the low melting temperature alloy 14 can be used. Alternatively, the insulation coating 60 is lower than the melting temperature of the low melting temperature alloy! Solvent-based coating materials that soften with temperature can be used. The insulating covering material 60 may be formed by applying an insulating coating to at least the temperature fuse portion of the connecting portion 13a of the varistor 1 and the separating conductor 13.

[0043] The NORISTA unit 40 having the insulating coating material 60 may be manufactured by the following process! The electrode lead wire 15 of the discharge gap 2 is connected to the common electrode 12 of the Norristor 1 with a high melting point solder 16 having a melting point of 200 ° C. or more (previous connection process). Thereafter, the connection portion 13a of the conductor 13 is disconnected from the three electrodes 11 of the NORISTR 1 and connected with the low melting temperature alloy 14 having a melting point of 200 ° C. or less (the subsequent connection step). If the first and second connection steps are reversed, it will be difficult to connect with a low melting temperature alloy. After these connection processes are completed, the insulating coating material 60 is applied (application process). In this application process, depending on the material of the insulating coating material 60, it can be applied to the spring portion 13c of the separating conductor 13 as well.

As shown in FIGS. 13 and 14, by storing the NORISTA unit 40 in which the temperature fuse portion of the connecting portion 13a of the NORISTR 1 and the disconnecting conductor 13 is covered with the insulating coating material 60 in the case 30, The thermal fuse part is double insulated with the insulation coating 60 and case 30 to increase the reliability of the insulation measures and to make the thermal fuse operation more stable. Further, when the varistor 1 is deteriorated, as shown in FIG. 15, before the low melting temperature alloy 14 is melted, the insulating coating material 60 is gelled. It enters a liquid or liquid state and enters between the electrode 11 of the NORISTR 1 and the connecting portion 13a of the disconnecting conductor 13. This intrusion and the disconnecting operation of the disconnecting conductor 13 described above ensure the electrical and mechanical disconnection between the noristor 1 and the disconnecting conductor 13 and increase the reliability of the thermal fuse operation.

[0045] The SPD with a separation mechanism of each of the above embodiments is a multi-terminal SPD used for a single-phase or three-phase three-wire AC circuit, but the present invention is not limited to this. A two-terminal varistor or the like in which a pair of electrodes are formed can also be applied. It can also be applied to SPDs with a disconnection function without a discharge gap.

Brief Description of Drawings

[0046] FIG. 1 is a side view including a partial cross section of an SPD with a separation mechanism showing a first embodiment of the present invention.

2 is a front view including a partial cross section of the SPD with a separation mechanism in FIG.

FIG. 3 is a side view of the assembly of the front stage of the SPD with a detachment mechanism of FIG.

4 is a side view of the rear stage of the SPD with a detachment mechanism shown in FIG. 1 during assembly.

FIG. 5 is a perspective view of a varistor and a NORISTA unit of its connecting parts in the SPD with a separation mechanism in FIG. 1.

FIG. 6 is a cross-sectional view of the varistor unit of FIG.

FIG. 7 is a cross-sectional view showing an outline of the essential parts of the varistor unit and case of the SPD with a separation mechanism in FIG. 1.

FIG. 8 is an equivalent circuit diagram of the SPD with a separation mechanism in FIG.

FIG. 9 is a side view showing an outline of the SPD with a detachment mechanism shown in FIG. 1 during assembly. FIG. 9A is a side view before assembly, and FIG. 9B is a side view after assembly.

FIG. 10 is a side view for explaining the breaking operation of the separation conductor of the SPD with the separation mechanism in FIG. 1. (A) is an operation diagram during actual breaking operation, and (B) and (C) are the separation conductors. FIG. 5 is an operation diagram for separately explaining different spring operations of spring portions.

FIG. 11 is a perspective view of a part of the SPD with a separation mechanism in FIG. 1 when the separation conductor and the display are assembled.

[Fig. 12] A side view including a partial cross-section of the SPD with a disconnecting mechanism in Fig. 1 during thermal fuse operation. is there.

FIG. 13] A side view including a partial cross section of an SPD with a separation mechanism showing a second embodiment of the present invention.

14 is a partially enlarged cross-sectional view of the SPD with a separation mechanism in FIG.

FIG. 15 is a partially enlarged cross-sectional view of the SPD with a disconnecting mechanism shown in FIG. 13 during operation of a thermal fuse.

1 Zinc oxide varistor

2 Discharge gap

11 electrodes

12 Common electrode

13 Pull-off conductor

13a connection

13b Display mounting part

13c Spring part

13p First spring force generator

13q Second spring force generator

13d fixed part

14 Low melting temperature alloy

15 Electrode lead conductor

16 High melting point solder

20 External terminal

30 cases

m space

30a first case

30b second case

32 Positioning means (of varistor)

Positioning means (for disconnected conductor) Parista unit Display Display panel Display window Insulation coating material

Claims

The scope of the claims

[1] A zinc oxide type varistor and a separated conductor that is bonded to the electrode of the varistor with a low melting temperature alloy and has a spring force that separates the electrode force when the low melting temperature alloy melts due to abnormal heat generation of the varistor. An SPD having a case for positioning and holding the varistor and the separating conductor;

The separating conductor includes a connecting portion joined to the electrode of the varistor, a spring portion extending from the connecting portion and bent, and a fixing portion extending and extending from the connecting portion and positioned and held in the case. Have

The case has positioning means for positioning and holding the varistor in a state in which the spring is provided by displacing the spring portion of the separating conductor when the varistor to which the separating conductor is connected is housed. SPD with detachment mechanism.

[2] The spring portion of the disconnecting conductor includes a first spring force generating portion that disconnects the connection portion from the electrode of the varistor in a translational manner when the low melting temperature alloy is melted, and the connection portion is connected to the first spring force. 2. The SPD with a detaching mechanism according to claim 1, further comprising a second spring force generating portion that rotates around the fixing portion via a generating portion to separate the electrode force of the varistor.

[3] The SPD with a detachment mechanism according to [1] or [2], wherein the detachment conductor is formed by either one of a wire or a plate.

[4] In the case, a space portion is formed that allows the connecting portion and the spring portion of the disconnecting conductor to be displaced by the restoring spring force of the spring portion when the low melting temperature alloy is melted. The SPD with a separation mechanism according to any one of claims 1 to 3.

[5] The separation mechanism according to any one of [1] to [4], wherein the case is a split-type case having at least a first case and a second case that are positioned and held with the varistor interposed therebetween. With SPD.

[6] An indicator for displaying abnormal heat generation of the varistor when the connecting portion of the disconnecting conductor is disconnected from the electrode force of the varistor when the low melting temperature alloy is melted is disposed in the case, 6. The SPD with a separation mechanism according to claim 4 or 5, further comprising a display window in which a display state of the display device is visible from outside the case.

[7] The varistor is a multi-terminal type having a plurality of electrodes connected to the line phase of the AC circuit on the front side and a common electrode of the ground phase on the back side, and a plurality of terminals corresponding to the line phase. 7. The SPD with a separation mechanism according to claim 6, wherein the separation conductor and the indicator are installed on each of the electrodes.

[8] The connecting portion between the varistor and the separating conductor is coated with an insulating coating material that is solid at room temperature and is in a gel or liquid state at a temperature lower than the melting temperature of the low melting temperature alloy. Item 8. SPD with a separation mechanism according to any one of 1 to 7.

[9] The SPD with a separation mechanism according to [8], wherein the insulating coating material is a liquefied liquid at a temperature lower than a melting temperature of the low melting temperature alloy.

10. The SPD with a separation mechanism according to claim 8, wherein the insulating coating material is a solvent-based coating material that softens at a temperature lower than the melting temperature of the low melting temperature alloy.

[11] A connecting step of connecting an electrode lead conductor with a high melting point solder of 200 ° C or higher to an electrode corresponding to the earth phase of an acid-zinc-type varistor having a plurality of electrodes of a line phase and an earth phase. After the connection step, the electrode corresponding to the line phase of the varistor is a low melting temperature alloy having a melting point of normal temperature to 200 ° C, and when the low melting temperature alloy is melted due to abnormal heat generation of the varistor. A method for producing an SPD with a separation mechanism, comprising a connection step of connecting a separation conductor having a spring force separated from the separation mechanism.

[12] The connecting step and the varistor connecting portion of the low-melting temperature alloy of the varistor and the separating conductor are solid at normal temperature, and are gel or liquid at a temperature lower than the melting point of the low-melting temperature alloy. 12. The method of manufacturing an SPD with a separation mechanism according to claim 11, further comprising a coating step of coating with an insulating coating material.