JP2010199515A - Varistor device and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a varistor device which can prevent insulation deterioration and prolong a life by securely coating a varistor element with insulating filler, is compact, and is suitable for an SPD for direct lightning stroke or the like. <P>SOLUTION: The varistor device includes an insulating cover 40 for closing an opening part of a case 30, and has a structure in which a lamination 80 is housed in a recessed part 31 of the case 30, the varistor element 10 and an electrode plate 20 are fastened in a press-contact state, the insulating filler is filled from an injection port 41 of the cover 40 to seal the lamination 80 in the case 30. Recessed grooves 35, which communicate with the injection port 41 of the cover 40 and in which the insulating filler is made to flow in between a peripheral wall surface 34 and an entire outer circumferential surface of the lamination 80, is arranged on the circumferential wall surface 34 of the recessed part 31 of the case 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a varistor device that can be applied to a direct lightning SPD or the like that incorporates a zinc oxide varistor element, absorbs a surge voltage caused by a direct lightning strike, and protects electrical equipment from the direct lightning strike.

  For example, in order to prevent lightning damage due to direct lightning strikes, a surge protection device (Surge Protective Device) is a device that shunts surge current by limiting transient overvoltage due to direct lightning strikes between electrical equipment and the ground in a single-phase AC circuit. : SPD) is installed. This direct lightning SPD includes a structure in which a zinc oxide varistor element is incorporated.

  The electrode structure of the varistor element includes a silver paste electrode by a printing method and an aluminum vapor deposition electrode by a vapor deposition method, and the silver paste electrode method is generally adopted because of the ease of solder connection and parallel use. In order to reduce the cost of the apparatus, a varistor element in which an aluminum vapor deposition electrode is formed is desirable. On the other hand, some varistor devices that are of the aluminum vapor deposition electrode type and are applied to SPD for direct lightning lightning have a structure in which a plurality of varistor elements are connected in parallel to improve surge resistance.

  This type of varistor device has a structure in which a plurality of disk-shaped varistor elements and disk-shaped electrode plates in contact with the electrode surfaces of the varistor elements are alternately stacked. As described above, the vapor deposition type aluminum vapor deposition electrode is formed on the electrode surface of the varistor element, and the electrode plate in contact with the electrode surface is interposed between the varistor elements in a state of being electrically connected in a predetermined arrangement relationship. Therefore, a structure in which a plurality of varistor elements are connected in parallel is employed (see, for example, Patent Document 1).

JP-A-2005-294459 (FIGS. 5 to 7)

  By the way, in the varistor element in which the aluminum vapor deposition electrode by the vapor deposition method is formed on the electrode surface as described above, the electrical connection is ensured by pressing the electrode plate against the electrode surface. Since the electrode surface of this varistor element is formed by vapor deposition, there are irregularities with a size of several tens of μm, and since the varistor element is a high-temperature sintered body, the varistor element itself is warped. Has occurred.

  Accordingly, in order to reduce the contact resistance when the electrode surface of the varistor element and the electrode plate are pressed, the varistor element or the electrode plate is distorted by a large applied pressure, or a soft metal body is interposed between the varistor element and the electrode plate. It is necessary to take measures to interpose the electrode plate and to form the electrode plate with a soft material. By adopting any of these means, the contact state between the varistor element and the electrode plate is improved, and a uniform surge current flows through the varistor element. A varistor device applied to a direct lightning SPD or the like is required to increase the capability of the varistor element.

  From the viewpoint of reliability, an airtight structure in which the varistor element is sealed with an insulating filler such as silicon resin is desirable in order to prevent insulation deterioration due to moisture absorption, creeping short-circuiting, and creeping contamination in the varistor element. In particular, when it is necessary to ensure a large surge current withstand such as a direct lightning strike, the peeling force due to static electricity acts on the insulating filler that covers the surface of the varistor element, so the varistor element is accommodated in the insulating case. In addition, it is necessary to enclose the insulating filler in the case.

  In this case, to reduce the size of the varistor device, if the gap between the varistor element and the case is reduced, the high-viscosity insulating filler does not easily enter the slit between the varistor element and the case, and the varistor element is insulated. It becomes difficult to reliably coat with a filler. In addition, in places where the pressure contact state between the varistor element and the electrode plate is not good, a slit is formed between the electrode surface of the varistor element and the electrode plate, and an insulating filler penetrates between them to further improve the contact state between the two. There is also the problem of making it worse. Specifically, there is a phenomenon in which the insulating filler that has penetrated into the slits expands and contracts by a long-term temperature cycle, and the slits gradually expand and the deterioration of the contact state proceeds.

  Accordingly, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is a compact that can reliably cover the varistor element with an insulating filler to prevent insulation deterioration and extend the life. It is an object of the present invention to provide a varistor device suitable for a direct lightning SPD or the like.

  As a technical means for achieving the above-described object, a varistor device according to the present invention includes a plurality of disc-shaped zinc oxide varistor elements and a varistor element in contact with each electrode surface of the stacked varistor elements. An insulative case having an electrode plate connected in parallel, an insulative case having a recess for accommodating a laminate composed of a varistor element and an electrode plate, and an insulating property between the peripheral wall surface of the recess of the case and the outer peripheral surface of the laminate An inlet for filling the filler is formed, and an insulating cover for closing the opening of the case is provided. The laminated body is accommodated in the recess of the case and tightened in a state where the varistor element and the electrode plate are pressed against each other. The laminated body is sealed in the case by filling an insulating filler from the cover inlet, and the outer peripheral surface of the laminate is connected to the inlet of the cover on the peripheral wall surface of the recess of the case. Insulating filling between Characterized in that a groove for flowing.

  In addition, a method of manufacturing a varistor device according to the present invention includes a laminate comprising a plurality of disc-shaped zinc oxide varistor elements and electrode plates that contact each electrode surface of the varistor elements and connect the varistor elements in parallel. The varistor element of the laminate and the electrode plate are brought into pressure contact by tightening and fixing the insulating cover that is accommodated in the recess formed in the insulating case and closes the opening of the case, and then the cover Insulating filler is injected from the injection port formed in the insulation, and insulation is made between the outer peripheral surface of the laminate through a concave groove formed in communication with the injection port of the cover on the peripheral wall surface of the recess of the case The laminate is sealed in the case with a filler filled with an insulating filler and filled with an insulating filler.

  In the present invention, since the laminated structure including the varistor element and the electrode plate is accommodated in the recess of the case and the opening of the case is closed with the cover, the varistor device is reduced in size and cost. In addition, since the varistor element and the electrode plate are in pressure contact with each other, an electrical connection between the varistor element and the electrode plate can be secured, and a varistor device having good characteristics can be provided.

  In addition, a concave groove is provided in the peripheral wall surface of the recess of the case so as to allow the insulating filler to flow into and out of the entire outer peripheral surface of the laminated body. The stored insulating filler is once stored in the concave groove so that it can easily flow into the entire outer peripheral surface of the laminate, and the entire outer peripheral surface of the laminate can be reliably covered with the filled insulating filler. In addition, it is possible to prevent insulation deterioration due to moisture absorption, creeping short circuit, creeping contamination, and the like in the varistor element, thereby improving reliability.

  In addition, the entire outer peripheral surface of the laminate has a double insulation structure with an insulating filler and case, which is strongly protected against peeling force acting on the insulating filler due to a large lightning surge current. Therefore, the insulating filler thin film covering the outer peripheral surface of the laminate is not scattered by lightning surges, and the same state is maintained over a long period of time, resulting in a long life.

  In the present invention, it is desirable that the gap between the portion excluding the groove on the peripheral wall surface of the recess of the case and the outer peripheral surface of the laminate is 0.2 to 1.5 mm. If the range of the gap is defined in this way, the outer peripheral surface of the laminate can be reliably covered with the insulating filler, and the varistor device can be made compact and low in cost at the same time. If this gap is smaller than 0.2 mm, it is difficult to reliably coat the outer peripheral surface of the laminate with an insulating filler, and insulation deterioration due to moisture absorption, creeping short circuit, creeping contamination, etc. may occur in the varistor element. There is. On the other hand, if the gap is larger than 1.5 mm, the amount of the insulating filler to be used increases, leading to an increase in cost and size of the varistor device.

  A structure in which a concave portion into which a pin for positioning the laminated body is fitted in the concave portion of the case is provided in a portion corresponding to the concave groove on the bottom surface of the concave portion of the case in the present invention. In this way, if a concave portion is provided in a portion corresponding to the concave groove on the bottom surface of the concave portion of the case, when the laminate is accommodated in the concave portion of the case, the pin is raised in the concave portion of the case by the concave portion, The position of the laminated body can be regulated in the recess by the pin. As a result, the gap between the peripheral wall surface of the recess of the case and the outer peripheral surface of the laminate can be made uniform over the entire circumference, making it easy to reliably fill the insulating filler and the gap. The dimensions can be easily set.

  In the present invention, the injection port is preferably formed in the central portion of the cover, and has a structure in which an introduction path extending radially from the injection port to the opening of the concave groove of the case is connected to the injection port. In this way, if the introduction path connecting the inlet of the cover and the gap between the cases is provided in the cover, the insulating filler from the inlet is guided to the introduction path and smoothly flows into the gap of the case. Thus, the insulating filler can be easily filled from the cover inlet to the gap of the case, and the workability can be improved.

  A structure in which a small hole for air venting is provided on the bottom surface of the recess of the case in the present invention is desirable. By providing a small hole in the bottom of the recess in this way, the air in the recess can be vented when filling with the insulating filler, so that the insulating filler can be quickly filled from the cover inlet to the gap of the case. Workability can be improved.

  The cover according to the present invention is preferably provided with a reinforcing metal plate having an inlet communicating with the inlet. If the reinforcing metal plate is attached as described above, the cover fastened and fixed to the case can be reinforced, and the thickness of the cover can be reduced correspondingly, and the varistor device can be easily made compact. .

  The electrode plate in the present invention preferably has a structure in which a large number of protrusions that can be deformed by pressure contact with the electrode surface of the varistor element are arranged uniformly on the contact surface with the electrode surface of the varistor element. By arranging a large number of protrusions evenly on the electrode surface in this way, it is possible to ensure that the electrode plate is in uniform contact over the entire surface in a pressure contact state with the electrode surface of the varistor element. Since the protrusion is deformed by pressure contact with the surface, the contact area can be secured, and local concentration of surge current can be avoided.

  According to the present invention, the varistor device is made compact and low-cost because the laminated body composed of the varistor element and the electrode plate is accommodated in the recess of the case and the opening of the case is closed with the cover. In addition, since the varistor element and the electrode plate are in pressure contact with each other, an electrical connection between the varistor element and the electrode plate can be ensured and a varistor device having good characteristics can be provided. .

  In addition, a concave groove is provided in the peripheral wall surface of the recess of the case so as to allow the insulating filler to flow into and out of the entire outer peripheral surface of the laminated body. The stored insulating filler is once stored in the concave groove so that it can easily flow into the entire outer peripheral surface of the laminate, and the entire outer peripheral surface of the laminate can be reliably covered with the filled insulating filler. In addition, it is possible to prevent insulation deterioration due to moisture absorption, creeping short circuit, creeping contamination, and the like in the varistor element, thereby improving reliability.

  In addition, the entire outer peripheral surface of the laminate has a double insulation structure with an insulating filler and case, which is strongly protected against peeling force acting on the insulating filler due to a large lightning surge current. Therefore, the insulating filler thin film covering the outer peripheral surface of the laminate is not scattered by lightning surges, and the same state is maintained over a long period of time, resulting in a long life.

  As a result, it is possible to provide a varistor device with high reliability, small size, low cost, and long life, and it becomes easy to apply the varistor device to a direct lightning SPD or the like.

It is an assembly exploded perspective view showing the whole composition of the varistor device in the embodiment of the present invention. FIG. 2 is a perspective view of assembly of the varistor device of FIG. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is an assembly exploded perspective view which shows the laminated body which consists of a varistor element and an electrode plate. FIG. 6 is a front view of FIG. 5. It is a front view which shows the state which assembled | attached the electrode plate to the varistor element of FIG. 6, and comprised the laminated body. It is an equivalent circuit diagram which shows the structure which connected the varistor element in parallel. It is a top view which shows a case. It is sectional drawing which follows the CC line of FIG. It is sectional drawing which follows the DD line | wire of FIG. It is a top view which shows a cover. It is a front view which shows the cover of FIG. It is a perspective view which shows the state which inject | poured the insulating filler into the varistor apparatus of FIG. It is sectional drawing which follows the EE line | wire of FIG. It is sectional drawing which follows the FF line | wire of FIG.

  Embodiments of the varistor device and the manufacturing method thereof according to the present invention will be described in detail below. The present invention is a varistor device suitable for a direct lightning SPD or the like that absorbs a surge voltage caused by a direct lightning strike with a zinc oxide varistor element and protects an electrical device from the direct lightning strike. 1 is an exploded perspective view of the varistor device, FIG. 2 is a perspective view of the assembled varistor device, FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a cross-sectional view taken along line BB in FIG. FIG.

  The varistor device of the embodiment shown in FIGS. 1 to 4 includes, for example, three zinc oxide varistor elements 10, four electrode plates 20 arranged corresponding to the number of the varistor elements 10, and an upper end being open. The substantially rectangular parallelepiped insulating case 30, the substantially rectangular insulating cover 40 closing the opening of the case 30, the substantially rectangular reinforcing metal plate 50 fitted to the cover 40, and the above-mentioned The case 30 includes four screws 60 that fasten and fix the cover 40 and the metal plate 50 as components, and an insulating filler 70 such as a silicone resin in the case 30 as described later (see FIGS. 14 to 16). Is filled. Note that the case 30 and the cover 40 described above may be made of resin, for example.

  As shown in FIGS. 5 and 6, the varistor element 10 has a disk shape in which an aluminum vapor deposition electrode is formed on the electrode surface 11 positioned in the vertical direction in the figure. As shown in FIG. 7, a laminate 80 is formed by alternately laminating three varistor elements 10 and four electrode plates 20. Of the four electrode plates 20 in contact with the electrode surface 11 of each varistor element 10, the two electrode plates 20 positioned first and third from the top in the figure are integrated with a U-shaped connecting portion 21. The two electrode plates 20 located second and fourth from the top in the figure are integrated by a U-shaped connecting portion 21 so as to be led out to both sides of the laminate 80 as shown in the equivalent circuit of FIG. The three varistor elements 10 are connected in parallel between the two connecting portions 21. Note that a hole 23 is formed in the connecting portion 21 of the electrode plate 20 so that the insulating filler 70 can easily flow.

  The case 30 in which the laminated body 80 including the varistor element 10 and the electrode plate 20 is accommodated is formed with a recess 31 for accommodating the laminated body 80 as shown in FIGS. On both sides in the figure, cutout portions 32 and 33 for accommodating a U-shaped connecting portion 21 protruding from the electrode plate 20 are connected at a depth corresponding to the position of each connecting portion 21.

  On the peripheral wall surface 34 of the recess 31 of the case 30, there is a recess groove 35 for allowing the insulating filler 70 to flow into the entire outer peripheral surface of the laminate 80 accommodated in the recess 31. It is formed along the direction. The illustrated grooves 35 are illustrated as being formed at four locations on the peripheral wall surface 34 of the recess 31, but the position and number thereof are arbitrary. A gap m (see FIG. 9) between a portion of the peripheral wall surface 34 of the recess 31 of the case 30 excluding the groove 35 and the outer peripheral surface of the laminated body 80 is set to 0.2 to 1.5 mm. In addition, as a dimension of this clearance gap m, 1 mm is preferable.

  Further, in a portion corresponding to the groove 35 on the bottom surface of the recess 31 of the case 30, a pin 90 for positioning the laminate 80 when the laminate 80 is accommodated in the recess 31 of the case 30 (FIG. 3 and FIG. 3). 4 is provided with a recessed portion 36 for standing and holding. Further, a small hole 37 is provided on the bottom surface of the recess 31 of the case 30 for releasing air when the insulating filler 70 is filled.

  The cover 40 that closes the opening of the case 30 is insulated at the central portion between the peripheral wall surface 34 of the recess 31 of the case 30 and the outer peripheral surface of the laminate 80 as shown in FIGS. An inlet 41 for filling the conductive filler 70 is formed, and an introduction path 42 that extends radially from the inlet 41 and reaches the opening of the concave groove 35 of the case 30 is connected to the inlet 41.

  On the upper surface of the cover 40, a recess 43 is formed in which a metal plate 50 for reinforcing the cover 40 is fitted. An injection port 51 is formed at the central portion of the metal plate 50 so as to correspond to the injection port 41 of the cover 40. Further, a small hole 52 through which a pin 90 standing and held by a recessed portion 36 formed in the bottom surface of the recess 31 of the case 30 is inserted is formed in a peripheral portion of the metal plate 50. Further, on one side of the lower surface of the cover 40, a protrusion 44 is formed that presses down one connecting portion 21 of the electrode plate 20 of the stacked body 80, that is, the connecting portion 21 positioned below in the drawing.

  The assembly of the varistor device composed of the components described above is performed as follows.

  First, it is composed of three varistor elements 10 and electrode plates 20 that are in contact with the electrode surfaces 11 of the varistor elements 10 to connect the varistor elements 10 in parallel, and a pair of connecting portions 21 led out from the electrode plates 20 are connected to each other. The laminated body 80 arranged in the opposite direction of 180 ° is configured (see FIGS. 5 to 7).

  The laminated body 80 is accommodated in the recess 31 of the case 30 and the connecting portion 21 of the electrode plate 20 is fitted into the notches 32 and 33 provided continuously to the recess 31. The cover 40 is placed in the opening of the case 30 in which the stacked body 80 is accommodated, and the protrusion 44 provided on one side of the cover 40 is fitted into the one notch 33 of the case 30.

  After fitting the metal plate 50 into the recess 43 of the cover 40, the cover 40 and the metal plate 50 are fastened and fixed to the case 30 with screws 60. The varistor element 10 and the electrode plate 20 in the laminated body 80 are held in pressure contact by tightening with the screws 60. In this state, the connecting portion 21 of the electrode plate 20 exposed to the notches 32 and 33 of the case 30 becomes a connection terminal in which the three varistor elements 10 are connected in parallel (see FIG. 8).

  Thereafter, the insulating filler 70 is injected from the injection ports 41 and 51 formed in the cover 40 and the metal plate 50. As shown in FIGS. 14 to 16, the insulating filler 70 injected from the injection ports 41 and 51 is guided by the introduction passages 42 formed radially in the cover 40, and surrounds the recess 31 of the case 30. Once stored in a concave groove 35 formed in the wall surface 34 in communication with the inlet 41 and the introduction path 42, the entire outer peripheral surface of the laminate 80 is interposed via the concave groove 35, that is, around the recess 31. The insulating filler 70 flows into the entire gap m between the wall surface 34 and the outer peripheral surface of the laminate 80. In this manner, the varistor element 10 and the electrode plate 20 in the laminate 80 are covered with the insulating filler 70 filled between the peripheral wall surface 34 of the recess 31 and the outer peripheral surface of the laminate 80, thereby stacking the laminate. The body 80 is sealed in the case 30. At this time, since the hole 23 (see FIG. 5) is formed in the connecting portion 21 of the electrode plate 20 of the laminate 80, the insulating filler 70 is also provided between the outer peripheral surface of the laminate 80 and the connecting portion 21. Will flow in quickly.

  This varistor device has a structure in which a laminate 80 composed of a varistor element 10 and an electrode plate 20 is accommodated in a recess 31 of a case 30 and an opening of the case 30 is closed with a cover 40 and a metal plate 50 by tightening screws 60. Therefore, the varistor device can be reduced in size and cost, and the varistor element 10 and the electrode plate 20 are in pressure contact with each other. Connection can be secured and it has good characteristics.

  In addition, the groove 35 allows the insulating filler 70 to flow into the peripheral wall surface 34 of the recess 31 of the case 30 between the inlet 41 and the introduction path 42 of the cover 40 and the entire outer peripheral surface of the laminate 80. Since the insulating filler 70 is temporarily stored in the concave groove 35 by the injection of the insulating filler 70 from the inlet 41 of the cover 40, the outer peripheral surface of the laminated body 80 and the periphery of the recess 31 are provided. The insulating filler 70 can easily flow into the entire gap m between the wall surface 34 and the entire outer peripheral surface of the laminate 80 can be reliably covered with the filled insulating filler 70, so that moisture absorption in the varistor element 10 can be achieved. In addition, it is possible to prevent insulation deterioration due to creeping short-circuiting or creeping contamination, and to improve reliability.

  In the state where the laminated body 80 is accommodated in the recess 31 of the case 30, the gap m between the portion excluding the groove 35 on the peripheral wall surface 34 of the recess 31 of the case 30 and the outer peripheral surface of the laminated body 80 is formed. By defining the range of 0.2 to 1.5 mm, the entire outer peripheral surface of the laminate 80 can be reliably covered with the insulating filler 70, and at the same time, the varistor device can be made compact and low in cost. be able to.

  If the gap m is smaller than 0.2 mm, it is difficult to reliably coat the outer peripheral surface of the laminate 80 with the insulating filler 70, and the varistor element 10 is subject to insulation deterioration due to moisture absorption, creeping short-circuiting, creeping contamination, and the like. May occur. On the other hand, if the gap m is larger than 1.5 mm, the amount of the insulating filler 70 to be used increases, leading to an increase in cost and size of the varistor device.

  Prior to housing the laminate 80 in the recess 31 of the case 30, the pin 90 is raised and held in the recessed portion 36 provided in a portion corresponding to the groove 35 on the bottom surface of the recess 31 of the case 30. The tip is projected from the opening of the case 30 (see the broken lines in FIGS. 3 and 4). Thus, by holding the pin 90 upright in the recessed portion 36 provided in the bottom surface of the recess 31 of the case 30, when the laminate 80 is accommodated in the recess 31 of the case 30, The position of the body 80 can be regulated in the recess 31.

  Thereby, the clearance m between the peripheral wall surface 34 of the recess 31 of the case 30 and the outer peripheral surface of the laminated body 80 can be made uniform over the entire circumference, and the insulating filler 70 is reliably filled. This facilitates the setting of the gap dimension. The laminated body 80 is accommodated in the recess 31 of the case 30 and positioned by the pin 90, and the cover 40 and the metal plate 50 are fastened and fixed by the screws 60, and then the small holes 52 of the metal plate 50 (see FIGS. 1 and 2). Pull out the protruding pin 90. The pin 90 is inserted through the introduction path 42 of the cover 40.

  The recess 36 for positioning the laminated body 80 in the recess 31 of the case 30 has a recess shape in which the pin 90 is inserted from the opening side of the case 30 and is held upright in the recess 31. The structure which penetrates the bottom face of may be sufficient. In this case, the pin 90 is inserted from the bottom surface side of the case 30 and disposed in the recess 31, and the laminated body 80 is positioned and fixed by fastening the cover 40 and the metal plate 50 with the screw 60 when the laminated body 80 is accommodated. Thereafter, the case 30 can be pulled out from the bottom side.

  When the insulating filler 70 is injected from the inlets 41 and 51 of the cover 40 and the metal plate 50, the introduction path extends radially from the inlet 41 of the cover 40 and reaches the groove 35 of the recess 31 of the case 30. 42 is connected to the injection port 41, so that the insulating filler 70 from the injection port 41 is guided to the introduction path 42 and between the outer peripheral surface of the laminated body 80 via the concave groove 35 of the case 30. Smoothly flows into the gap m. Thereby, the filling of the insulating filler 70 from the inlet 41 of the cover 40 to the gap m of the case 30 can be easily performed, and workability can be improved.

  Further, when the insulating filler 70 is injected from the inlets 41 and 51 of the cover 40 and the metal plate 50, a small hole 37 is provided in the bottom surface of the recess 31 of the case 30, so that the insulating filler 70 Since the air in the recess 31 can be vented at the time of filling, the insulating filler 70 can be quickly filled from the inlet 41 of the cover 40 into the gap m of the case 30 and workability can be improved. At this time, the small holes 52 provided in the metal plate 50 also function as air vents.

  Since the cover 40 is provided with the metal plate 50 in the recess 43, the cover 40 fastened and fixed to the case 30 with the screw 60 can be reinforced, and the thickness of the cover 40 is reduced accordingly. This makes it easy to make the varistor device compact.

  In the electrode plate 20, a large number of protrusions 22 that can be deformed by pressure contact with the electrode surface 11 of the varistor element 10 may be arranged evenly on the contact surface with the electrode surface 11 of the varistor element 10 (FIG. 5). reference). In this way, by arranging a large number of protrusions 22 on the contact surface of the varistor element 10 with the electrode surface 11, the electrode plate 20 is uniformly contacted over the entire surface in a pressure contact state with the electrode surface 11 of the varistor element 10. The state can be ensured, and the protrusion 22 can be deformed by the pressure contact with the electrode surface 11 of the varistor element 10, so that the contact area can be secured, and local concentration of surge current can be avoided. it can.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims, and the equivalent meanings recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 10 Varistor element 11 Electrode surface 20 Electrode plate 21 Connecting part 22 Protrusion 30 Insulating case 31 Recess 34 Circumferential wall 35 Recessed groove 36 Recessed part 37 Air vent small hole 40 Insulating cover 41 Inlet 42 Inlet path 43 Recessed part 50 Reinforcing Metal plate 70 Insulating filler 80 Laminate 90 Pin m Gap

Claims (9)

A plurality of disc-shaped zinc oxide varistor elements, an electrode plate that contacts each electrode surface of the stacked varistor elements and connects the varistor elements in parallel, and a recess that accommodates the laminate composed of the varistor elements and the electrode plates And an inlet for filling the insulating filler between the peripheral wall surface of the recess of the case and the outer peripheral surface of the laminate, and closing the opening of the case An insulating cover, and the laminate is accommodated in the recess of the case and tightened in a state where the varistor element and the electrode plate are pressed against each other, and the laminate is filled by filling the insulating filler from the inlet of the cover. It is structured so that it is sealed in the case, and a concave groove is provided on the peripheral wall surface of the recess of the case so as to allow the insulating filler to flow into the entire outer peripheral surface of the laminate in communication with the cover inlet. A varistor device.   2. The varistor device according to claim 1, wherein a gap between a portion of the peripheral wall surface of the recess of the case excluding the groove and an outer peripheral surface of the laminated body is set to 0.2 to 1.5 mm.   3. The varistor device according to claim 1, wherein a recess portion into which a pin for positioning the laminated body in the recess of the case is fitted is provided at a portion corresponding to the recess groove on the bottom surface of the recess of the case.   The injection port is formed at a central portion of the cover, and an introduction path that extends radially from the injection port and reaches the opening of the concave groove of the case is connected to the injection port. The varistor device described in 1.   The varistor apparatus as described in any one of Claims 1-4 which provided the small hole for air venting in the recess bottom face of the said case.   The varistor device according to any one of claims 1 to 5, wherein the cover is provided with a reinforcing metal plate having an injection port communicating with the injection port.   The varistor according to any one of claims 1 to 6, wherein the electrode plate has a large number of protrusions that can be deformed by pressure contact with the electrode surface of the varistor element on a contact surface with the electrode surface of the varistor element. apparatus.   A laminated body composed of a plurality of disc-shaped zinc oxide varistor elements and electrode plates that contact each electrode surface of the varistor elements and connect the varistor elements in parallel is accommodated in a recess formed in an insulating case. Then, an insulating cover that closes the opening of the case is fastened and fixed to the case to bring the laminated varistor element and the electrode plate into a pressure contact state, and then an insulating filler is injected from the inlet formed in the cover. The insulating filler is poured into the peripheral wall surface of the recess of the case through the recessed groove formed in communication with the injection port of the cover and into the entire outer peripheral surface of the laminate. A method of manufacturing a varistor device, wherein the laminated body is sealed in a case with an insulating filler.   Prior to accommodating the laminate in the recess of the case, a pin is raised in the recess of the case by a recessed portion formed in a portion corresponding to the groove on the bottom surface of the recess of the case, and the laminate is formed by the pin. The method for manufacturing a varistor device according to claim 8, wherein the varistor device is positioned in the recess.

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