JP2007305934A - Surge protection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and reliable surge protection device. <P>SOLUTION: Two plate-like voltage nonlinear resistance substrates 7 and 11 one of which is twice as thick as the other are used. Common electrodes 8 and 12 are formed on one of the main surfaces of each, and two or more electrodes 9 and 10 and electrodes 13 and 14 are formed separately from each other on the other. The substrates 7 and 11 are arranged so that the two or more electrodes 9 and 13 and the electrodes 10 and 14 may oppose each other, and draw-out terminals 4 and 5 are interposed between each of them to be connected and integrated. Moreover, on the common electrode 12 of a thick substrate 11, a common draw-out terminal 6 is arranged and connected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surge protection device, and more particularly to a surge protection device for protecting a device connected to an AC distribution line from a lightning surge or the like.

  Surge protection devices installed on power lines such as single-phase two-wire AC distribution lines, DC distribution lines, and single-phase two-wire AC distribution lines are usually connected between lines and between each line and ground. As described above, independent components such as a voltage nonlinear resistance element are mounted on a printed wiring board by a method such as soldering.

  Since this device is configured using individual voltage nonlinear resistance elements, the variation in characteristics between them is quite large, and as a result, it is very difficult to reduce the variation in characteristics as a device. It has become. In addition, a plurality of voltage nonlinear resistance elements must be soldered to the printed circuit board at predetermined positions, which complicates the mounting operation and inspection of the mounting state, and requires a long time for mounting and inspection. It is said. Further, the mounting area is increased, the printed wiring board is increased in size, and the device is increased in size. Furthermore, when the mounting substrate is housed in an insulating case, the device is further increased in size, and it is extremely difficult to reduce the size of the device when it is built in an electric device or an electronic device.

  By the way, as a method for reducing the mounting man-hours, three voltage non-linear resistance elements are overlapped with an electrode lead terminal plate made of a good conductor, and the outer electrodes of the voltage non-linear resistance elements on both outer sides are drawn out. It has been proposed to connect with a terminal board (eg, Patent Document 1).

  According to this method, although the advantage that the number of connection points at the time of device assembly can be reduced and the size can be reduced is obtained, the device is assembled by using a necessary number of individual voltage nonlinear resistance elements. The characteristics are directly affected by variations in characteristics between elements, and it has been very difficult to improve the reliability of the device.

  On the other hand, devices having a predetermined circuit configuration in which a plurality of electrodes are formed on a flat voltage nonlinear resistance base have been proposed (eg, Patent Documents 2 and 3).

These devices require few connection points, are extremely easy to manufacture, and are constructed using a common substrate, so that the characteristics between the characteristic elements are substantially the same. In terms of performance, it is superior to the above devices.
Japanese Utility Model Publication No. 57-150906 JP 2003-9387 A JP 2003-22883 A

  However, in this device, since the electrodes are two-dimensionally arranged on the voltage non-linear resistance substrate with the pair of electrodes facing each other, a substrate having a large main surface area is required. The device itself becomes very large. For this reason, in order to use it for an application in which a device mounting space is limited, it is strongly desired to reduce the size.

  The present invention seeks to provide a small and highly reliable surge protection device that solves these problems.

  The surge protection device of the present invention has two parallel principal surfaces, a common electrode formed on one of the principal surfaces, and a plurality of electrodes spaced apart on the other. The first and second voltage non-linear resistance bases are arranged and connected so that a plurality of electrodes are opposed to each other, an extraction terminal is interposed between the opposed electrodes, and the first and second voltage non-linear resistance bases are further provided. A common lead-out terminal is arranged and connected on any one common electrode of the linear resistance base.

  In this device, the first and second voltage non-linear resistance bases are connected with a plurality of electrodes provided on one surface facing each other, and lead terminals are arranged between them, and further, voltage non-linearity Since one common electrode of the resistance base is arranged and connected, the number of connection points at the time of mounting is reduced, and mass production becomes easy. Furthermore, since the non-linear element formed between the common electrode and the plurality of electrodes in each voltage non-linear resistance base is the same base, the current-voltage non-linearity is substantially the same. This eliminates the variation in characteristics suitable for a device composed of individual elements.

  Furthermore, in the surge protection device of the present invention, the separation distance of the plurality of electrodes on the other main surface of each of the voltage nonlinear resistance bases is made larger than any of the thicknesses of the voltage nonlinear resistance bases.

  According to this, since the voltage nonlinearity between the electrodes depends on the thickness direction of the substrate and conducts in the region between the electrodes facing the surge voltage through the substrate, the in-plane direction of the substrate, that is, the same main The conduction between the electrodes arranged on the surface is suppressed.

  Furthermore, in the surge protection device of the present invention, the voltage non-linear resistance base having a common lead terminal has a separation distance between a plurality of electrodes facing the common lead terminal via the base, and is at least 2 of the thickness of the base. Doubled.

  In this device, when a surge voltage is applied, conduction is made in a region between electrodes facing each other through the substrate, and conduction between electrodes arranged in the in-plane direction of the substrate, that is, on the same main surface is prevented.

  Furthermore, in the surge protection device of the present invention, the rising voltages per unit thickness of the current-voltage nonlinear characteristics of the first and second voltage nonlinear resistance substrates are equal, and the second voltage nonlinear resistance The thickness of the substrate is twice that of the first voltage nonlinear resistance substrate, and a common lead terminal is disposed on the common electrode of the second voltage nonlinear resistance substrate.

  In this device, the common electrode in the first voltage nonlinear resistance substrate serves as a conductor that connects two characteristic elements formed between the electrodes facing each other through the substrate in series. And, by connecting the common lead terminal to the ground and connecting the lead terminals arranged between a plurality of electrodes to each distribution line, it is possible to provide surge protection for single-phase two-wire distribution lines with a single device. . In addition, since the rising voltage per unit thickness of the current-voltage nonlinear characteristics in both substrates is made equal, it becomes possible to manufacture using the same raw material, and management of the raw material and manufacturing conditions becomes easy. .

  Furthermore, in the surge protection device of the present invention, the rising voltage of the current-voltage nonlinear characteristic in the thickness direction of the second voltage nonlinear resistance substrate is changed in the thickness direction of the first voltage nonlinear resistance substrate. A common lead-out terminal was arranged on the common electrode of the second voltage non-linear resistance base, and the current-voltage non-linear rising voltage was doubled.

  In this device, the common electrode in the first voltage nonlinear resistance substrate serves as a conductor that connects two characteristic elements formed between the electrodes facing each other through the substrate in series. And, by connecting the common lead terminal to the ground and connecting the lead terminals arranged between a plurality of electrodes to each distribution line, it is possible to provide surge protection for single-phase two-wire distribution lines with a single device. . Further, since the ratio of the rising voltage of the current-voltage nonlinear characteristics in the first and second substrates is set to 1: 2, it is possible to select different materials for both substrates, and there are restrictions on the selection of raw materials. Is reduced.

  Furthermore, in the surge protection device of the present invention, each of the electrodes formed on the main surface of the first and second voltage nonlinear resistance bases and the lead terminal is made of either solder or conductive resin. By electrically connecting the bases, it is possible to mass-produce structurally strong devices by integrating these bases.

  Then, by configuring the lead terminal with a plate-like conductor in which one or a plurality of through holes are formed, the integration of these bases is further strengthened.

  According to the surge protection device of the present invention, the number of connection points can be reduced, and the number of mounting steps on the mounting board can be reduced. In addition, multiple characteristic elements are composed of the same voltage nonlinear resistance base, and the characteristics of the elements in the base are substantially the same, so the variation in characteristics is greatly reduced compared to devices composed of individual elements. And a highly reliable device can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a view showing an appearance of a surge protection device used in a single-phase two-wire distribution line, and FIG. 2 is a view showing a structure of a main part thereof.

  As shown in the side view of FIG. 1A, this device has two voltage non-linear resistance elements 1 and 2 having a substantially rectangular main surface and a plate shape, and an epoxy that hermetically seals them. As shown in the top view of FIG. 1B and the bottom view of FIG. 1C, the insulating cover 3 made of resin or the like protrudes from one of the end faces located between the long sides. It has three plate-like lead terminals 4, 5, and 6 in which tongue-like portions are integrally formed. The terminals 4 and 5 are terminals connected to the respective lines of the two-phase single-wire distribution line, and the terminal 6 is a terminal connected to the ground.

  As shown in the element cross-sectional view of FIG. 2A, the voltage nonlinear resistance element 1 has a substantially rectangular and flat voltage nonlinear resistance base 7 as a characteristic element. The corners of the base 7 are curved surfaces that are continuous with two orthogonal end faces. On one main surface of the element 1, as shown in FIG. 2B, a common electrode 8 serving as a conductor in the in-plane direction is formed over the entire region excluding the region having a predetermined width along the periphery. Is formed. On the other main surface, as shown in FIG. 2 (c), two electrodes 9 and 10 are separated from each other in the longitudinal direction of the main surface and at a predetermined interval from the edge of the substrate 1. It is formed in the plane.

  The voltage non-linear resistance element 2 includes a voltage non-linear resistance base 11, a common electrode 12, and two electrodes 13 and 14 formed so as to face each other across the base 12. The electrodes 13 and 14 are arranged to be equal to the distance between the electrodes 9 and 10 in the element 1.

The substrates 7 and 11 are made of ceramics containing zinc oxide as a main component and a component for expressing current-voltage nonlinear characteristics. These substrates 7 and 11 are made of zinc oxide (ZnO) as a main component, and components for causing the obtained ceramic to exhibit current-voltage nonlinear characteristics such as bismuth oxide (Bi ₂ O ₃ ), antimony oxide (Sb ₂ ). O ₃ ), cobalt oxide (Co ₃ O ₄ ), manganese oxide (MnO ₂ ), nickel oxide (NiO), aluminum nitrate nonahydrate (Al (NO ₃ ) ₃ .9H ₂ O), and boron oxide (B ₂ O ₃ ) and the like are added at a predetermined ratio, formed into a plate shape, and then fired at a temperature in the range of 870 to 1050 ° C. in the atmosphere. Needless to say, the present invention is not limited to the above-described additive components, and current-voltage nonlinearity can also be expressed by using rare earth elements such as praseodymium (Pr) instead of bismuth.

  When the rising voltages of the current-voltage non-linear characteristics per unit thickness of the substrates 7 and 11 are equal, the substrates 7 and 11 have a rising voltage in the thickness direction of the substrate 7 that is ½ that of the substrate 11. It is manufactured by controlling the thickness of 7, 11 and the firing conditions. When the rising voltages per unit thickness are equal, the relationship between the thicknesses of the substrates 7 and 11 is 1: 2. Needless to say, the ratio of the rising voltage of the current-voltage nonlinear characteristic in the thickness direction of the substrate 7 to that of the substrate 11 may be set to 1: 2 without making the rising voltages per unit thickness uniform. According to this, it is possible to relieve the restrictions on selecting raw materials.

  The electrodes 8 to 10 and the electrodes 12 to 14 are formed by applying a silver paste in a predetermined pattern on the main surfaces of the substrates 7 and 11 by a screen printing method and baking the same.

  Then, the electrodes 9 and 13 and the electrodes 10 and 14 face each other, and lead terminals 4 and 5 for connecting to the distribution lines are arranged between them, and further by conductive adhesive or soldering. Connecting. Thereby, the voltage non-linear resistance elements 1 and 2 are firmly integrated. As shown in FIG. 2D, the common lead terminal 6 to be connected to the ground terminal is connected to the electrode 12 of the element 2 using a conductive adhesive or soldering.

  Here, in the elements 1 and 2, the separation distance between the electrodes 9, 10, 13, and 14 formed on the same surface of each of the base bodies 7 and 11 is larger than the thickness of the base bodies 7 and 11, respectively. Thus, when a surge voltage is applied, the characteristic element of the substrate portion between the electrodes 8 and 9 or between the electrodes 8 and 10 in the substrate 7, and between the electrodes 13 and 12 or between the electrodes 14 and 12 in the substrate 11. Thus, the base portion is electrically conducted, and the occurrence of conduction between the electrodes 9 and 10 and the electrodes 13 and 14 arranged in the same plane is prevented. According to experiments, it is recommended that the distance between the electrodes 4 and 5 and 13 and 14 be at least twice the thickness of the substrates 7 and 11, respectively. In this example, since the electrodes 9 and 13 and the electrodes 10 and 14 are connected to face each other, the distance between the electrodes 9 and 10 is equal to that between the electrodes 13 and 14, so that the voltage nonlinear substrate The distance between the electrodes 13 and 14 of the element 2 having the higher rising voltage in the thickness direction and the thickness of the substrate 11 may be in the above-described dimensional relationship.

  As shown in the equivalent circuit diagram of FIG. 4, in this device, the characteristic element 15 is formed by the voltage nonlinear resistance base 7 and the electrodes 9 and 8, and the characteristic element 16 is formed by the base 7 and the electrodes 10 and 8, respectively. It is formed. These elements 15 and 16 are connected in series by the common electrode 8 and both ends thereof are connected to the lead terminals 4 and 5. Further, a characteristic element 17 is formed by the voltage non-linear resistance base 11 and the electrodes 12 and 13, and a characteristic element 18 is formed by the base 11 and the electrodes 12 and 14, respectively, which are independent of the common lead terminal 6. Connected between the lead terminals 4 and 5, respectively.

  The lead terminals 4 and 5 are connected to the distribution line terminals 19 and 20, respectively, and the lead terminal 6 is connected to the ground terminal 21.

  In the above-described surge protection device, the rising voltages of the nonlinear characteristics in the thickness direction of the two voltage nonlinear resistance bases 1 and 2 have a 1: 2 relationship, and the main surfaces on which a plurality of electrodes are formed are opposed to each other. Since the corresponding electrodes 9, 13, 10, 14 are joined with the lead terminals 4, 5 using conductive adhesive or solder, the electrodes are two-dimensionally arranged in the same plane. Compared with the case where it arrange | positions in, it can be remarkably miniaturized. In addition, since the common lead terminal 16 is joined to the common electrode 12 of the base 2 having a high rising voltage by the same method and the common electrode 8 of the base 1 is connected to two characteristic elements, the number of man-hours required for connection is reduced. The device can be greatly reduced, and the characteristic variation between the characteristic elements is small. The lead terminals 4, 5 and 6 are arranged so that the tongue-like portions protrude in one direction, so that the elements 1 and 2 can be easily sealed with an insulating resin, for example, an epoxy resin. It can be easily mass-produced at low cost.

  Further, as shown in FIGS. 4 (a) and 4 (b), the lead terminals 4 and 5 are provided with terminals in which one or a plurality of through holes 22 and 23 having various shapes such as a circle and a polygon are formed. By using the conductive paste or solder between the voltage non-linear resistance bases 1 and 2 and the lead terminals 4 and 5 through the through holes 22 and 23, the joint strength can be increased. . Of course, the joint lead terminal 6 can also be increased in bonding strength with the base body 11 through the common electrode 12 by using a terminal having a similar structure. Also, by roughening the surfaces of the lead terminals 3, 4 and 6, it is possible to increase the area where the conductive paste or solder contacts, and to increase the bonding strength.

  Furthermore, in the above example, two electrodes 9 and 10 and electrodes 13 and 14 are provided on the opposing surface side of the voltage nonlinear resistance bases 7 and 11, respectively. A device useful for surge protection measures in a three-phase AC distribution system can be provided by arranging and integrating the lead terminals between corresponding electrodes as in the above example.

(A) is a side view of an example of an embodiment of the surge protection device of the present invention, (b) is a top view thereof, and (c) is a bottom view thereof. (A) is sectional drawing of the surge protection element in embodiment shown in FIG. 1, (b) is bb sectional drawing of (a), (c) is cc sectional drawing of (a). FIG. 2 is an equivalent circuit diagram of the embodiment shown in FIG. 1. (A), (b) is a top view which shows the other structural example of an extraction terminal, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Voltage non-linear resistance element 3 Insulation coating body 4,5 Plate-like extraction terminal 7 Voltage non-linear resistance base | substrate 8 Common electrode 9,10 electrode 11 Voltage non-linear resistance base | substrate 12 Common electrode 13,14 Electrode 15, 16, 17, 18 Characteristic element 19, 20 Distribution line terminal 22, 23 Through hole

Claims (9)

  A plate-like first and second plate having two parallel principal surfaces, a common electrode formed on one of the principal surfaces, and a plurality of electrodes spaced apart on the other of the principal surfaces; The two voltage nonlinear resistance bases are arranged with the plurality of electrodes facing each other, and connected with each other with an extraction terminal interposed between the opposing electrodes, and the first and second voltage nonlinearities are connected. A surge protection device in which a common lead-out terminal is placed and connected on either common electrode of the resistor base.   A separation distance between a plurality of electrodes on the other main surface of each of the first and second voltage nonlinear resistance bases is larger than any of the thicknesses of the first and second voltage nonlinear resistance bases. The surge protection device according to Item 1.   A common lead terminal is provided on the second voltage non-linear resistance base, and a separation distance between the plurality of electrodes on the second voltage non-linear resistance base is the second voltage non-linear resistance base. The surge protection device according to claim 1 or 2, wherein the surge protection device is at least twice the thickness of the device.   The rising voltages per unit thickness of the current-voltage nonlinear characteristics of the first and second voltage nonlinear resistance substrates are equal, and the thickness of the second voltage nonlinear resistance substrate is the first voltage nonlinear resistance substrate. The surge protection device according to claim 1, 2 or 3, wherein the common lead-out terminal is arranged on a common electrode of the second voltage non-linear resistance base, which is twice the voltage non-linear resistance base.   The rising voltage of the current-voltage nonlinear characteristic between the common electrode on one main surface and the electrode on the other main surface in the second voltage nonlinear resistance base is the first voltage nonlinearity. 2 times the rising voltage of current-voltage nonlinearity between the common electrode on one main surface and the electrode on the other main surface of the resistive substrate, the second voltage nonlinear resistive substrate The surge protection device according to claim 1, wherein the common lead terminal is disposed on a common electrode.   6. Each of the electrodes formed on the main surface of the first and second voltage nonlinear resistance bases and the lead terminal are electrically connected with either solder or conductive resin. The surge protection device according to any one of the above.   The surge protection device according to any one of claims 1 to 6, wherein the lead terminal is made of a plate-like conductor in which one or a plurality of through holes are formed.   The surge protection device according to any one of claims 1 to 7, wherein the voltage non-linear resistance base is made of a ceramic mainly composed of zinc oxide.   The surge according to any one of claims 1 to 8, wherein the first and second voltage non-linear resistance bases, the electrode, and an extraction terminal connected to the electrode are covered with a sealing body made of an insulating material. Protective device.

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