JPH069448Y2 - Chip-shaped varistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a chip-shaped varistor for protecting an electronic device from an abnormal voltage.

[Prior Art] A first electrode is provided on most of one main surface, one side surface, and a part of the other main surface of a rectangular varistor element body, and A chip-shaped varistor in which the second electrode is provided on most of the other side surface and a part of the one main surface is disclosed in, for example, Japanese Patent Publication No. 58-85501.

[Problems to be Solved by the Invention] However, since the first and second electrodes are provided on the same main surface of the varistor element body, it is difficult to obtain a large surge resistance. In addition, it is difficult to obtain a large opposing portion between the first electrode and the second electrode, and it is difficult to obtain a large surge resistance and a large electrostatic capacitance. Furthermore, when the first and second electrodes are formed by applying a silver paste and baking the electrodes, when the external conductors are connected to the first and second electrodes by solder, the phenomenon that the solder absorbs the silver electrode ( There is a problem in that solder solder) occurs and the characteristics deteriorate.

On the other hand, in order to increase the area where the electrodes face each other, the first electrode may be provided only on one main surface of the varistor element body and the second electrode may be provided only on the other main surface of the varistor element body. However, in this case, the configuration of the external connection electrode was troublesome.

Therefore, an object of the present invention is to provide a chip-shaped varistor capable of increasing surge resistance and easily obtaining an external connection portion.

[Means for Solving the Problems] The present invention for achieving the above object will be described with reference to the reference numerals of the drawings showing the embodiments, and a plate-shaped varistor element body 1 having a substantially rectangular planar shape, The first electrode 2 provided on one main surface of the varistor element body 1, the second electrode 3 provided on the other main surface of the varistor element body 1, and the first electrode 2.
First external connection conductor 4 connected to the electrode 2, a second external connection conductor 5 connected to the second electrode 3, the varistor element body 1, the first and second electrodes 2 In the chip-shaped varistor, the chip-shaped varistor comprising: 3 and an insulating coating 6 provided so as to cover a part of the first and second external connecting conductors 4, 5; 4,5
Respectively have first plate-like portions 7 and 8 having vertically extending portions and second plate-like portions 9 and 10 having horizontally extending portions, respectively, and the second plate-like portions 9 and 10 are provided. Is a portion extending substantially perpendicularly from the first plate-shaped portions 7 and 8 between one end and the other end of the first plate-shaped portions 7 and 8, and the first external connection conductor The second plate-shaped portion 9 of No. 4 is arranged so as to be in contact with the first electrode 2, and is connected to at least a part of the first electrode 2 with solder 11, The first plate-shaped portion 7 of the external connection conductor 4 is arranged in parallel to one side surface of the varistor element body 1, and the second plate-shaped portion 10 of the second external connection conductor 5 is arranged.
Is arranged so as to be in contact with the second electrode 3 and is bonded to at least a part of the second electrode 3 with a solder 12, and the first plate of the second external connection conductor 5 is The strip-shaped portion 8 is arranged so as to be parallel to the other side surface of the varistor element body 1 and to face the first plate-shaped portion 7 of the first external connection conductor 4, and the insulating coating body 6 is at least the above-mentioned. One end and the other end of the first plate-shaped portions 7 and 8 of the first and second external connection conductors 4 and 5 which are provided on one and the other main surface sides of the varistor element body 1 are the insulating coatings. Body 6
The present invention relates to the chip-shaped varistor exposed on the one and the other main surfaces 6a and 6b, respectively.

[Operation] The first and second external connection conductors 4, 5 in the above invention
Has first plate-shaped portions 7 and 8 and second plate-shaped portions 9 and 10, and makes the second plate-shaped portions 9 and 10 in contact with the first and second electrodes 2 and 3. Therefore, the second plate-shaped portions 9 and 10 can be easily and surely brought into contact with the first and second electrodes 2 and 3 regardless of variations in the thickness of the varistor element body 1. Since one end and the other end of the first and second external connection conductors 4 and 5 are exposed on both main surfaces of the insulating coating 6,
Connection to an external circuit is possible using any of the main surfaces of the chip varistor.

[Embodiment] A chip-shaped varistor according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7. As is clear from FIGS. 1 and 2, the chip-shaped varistor includes a varistor element body 1,
The first and second electrodes 2 and 3, the first and second external connection conductors 4 and 5, and the insulating coating 6 are provided.

As shown in FIG. 3, the varistor element body 1 is a square quadrangular in plan view, and is formed with a vertical width of 6 mm, a horizontal width of 8 mm, and a height of 1.6 mm. The varistor element body 1 is a ceramic containing strontium titanate (SrTiO3) as a main component, and can obtain varistor characteristics and electrostatic capacity.

For the first and second electrodes 2 and 3, silver conductive paste is applied to almost all of one and the other main surfaces of the varistor element body 1,
Ohmic silver electrodes formed by baking at 00 ° C. for 45 minutes, each having an electrode area of 5 × 7 mm.

The first and second external connection conductors 4 and 5 are composed of vertical plate-shaped portions 7 and 8 as first plate-shaped portions and horizontal plate-shaped portions 9 and 10 as second plate-shaped portions, and are the same as each other. And one of them is arranged upside down. Each horizontal plate-shaped portion 9, 10 is arranged at a right angle to the surface of each vertical plate-shaped portion 7, 8 between one end 7a, 8a and the other end 7b, 8b of each vertical plate-shaped portion 7, 8. . The width a of the vertical plate-shaped portions 7 and 8 and the horizontal plate-shaped portions 9 and 10 of each external connection conductor 4 and 5.
Is 4 mm, the thickness b of the vertical plate-shaped portions 7, 8 is 2 mm, the lateral width c of the horizontal plate-shaped portions 9, 10 is 5 mm, and one end 7a, 8a of the horizontal plate-shaped portions 9, 10 to the vertical plate-shaped portions 7, 8 The height d up to 1.2 mm, the thickness e of the horizontal plate portions 9 and 10 is 0.1 mm,
The height f of the vertical plate-shaped portions 7 and 8 is 4.0 mm. In addition,
The first and second external connection conductors 4 and 5 are formed by providing a solder plating layer on brass. Also, the horizontal plate-shaped portions 9, 1
0 is fixed to the vertical plate-shaped portions 7 and 8 by welding.

Horizontal plate-like portions 9 of the first and second external connection conductors 4 and 5,
10 is arranged to face the first and second electrodes 2 and 3, and S
It is connected by solders 11 and 12 made of n: Pb = 60: 40.

The vertical plate-shaped portions 7 and 8 are arranged so as to face one side surface 1a and the other side surface 1b of the varistor element body 1 at intervals of 0.5 mm.

The insulating cover 6 is made of epoxy resin and is provided so that only one end 7a, 8a and the other end 7b, 8b of each vertical plate-shaped portion 7, 8 are exposed and the other is covered. Therefore,
The vertical plate portions 7 and 8 and both side surfaces 1a of the varistor element body 1,
The insulating coating 6 is also filled in between 1b.

In the completed chip-shaped varistor, Figs.
As is clear from the figure, one main surface 6a of the insulating coating 6 is
One end 7a of one vertical plate-shaped portion 7 and the other end 8b of the other vertical plate-shaped portion 8 are exposed from the other, and the other end 7b of one vertical plate-shaped portion 7 from the other main surface 6b of the insulating cover 6 and One end 8a of the other vertical plate-shaped portion 8 is exposed. The insulating coating 6 has a vertical width of 8 mm, a horizontal width of 10 mm, and a height of 4 mm.

The completed varistor has a varistor voltage of 240 v and a capacitance of 3000 pF. In addition, a surge current is repeatedly supplied to the varistor at regular intervals 10 times, and the difference between the varistor voltage before the start of the test and the varistor voltage after the end of the test is ± The maximum surge current value that can be kept within 10% was 1500 A. In addition, when the external connection conductors 4 and 5 are connected to the wiring conductors of the circuit board by soldering at 240 ° C., the soldering of the first and second electrodes 2 and 3 by the solders 11 and 12 inside the varistor is 100 When the varistor was examined, no varistor was generated.

For comparison, a first electrode is provided on one main surface, one side surface, and a part of the other main surface of the varistor element body having the same size as that of the example, and the varistor element body is provided with the other main surface. A varistor having a second electrode provided on the other side surface and a part of one main surface was formed, and the maximum surge current was obtained by the same method as that of the embodiment. As a result, it was 500 A, which was 1/3 of that of the embodiment. there were. The capacitance of this comparative example is 1500 pF,
Was 2. In addition, in the comparative example, 5 solder defects were generated in 100 varistor.

[Modification] The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example.

(1) As shown in FIG. 8, the external connection conductors 4 and 5 may be joined to the vertical plate portions 7 and 8 by folding the end portions into L-shaped horizontal plate portions 9 and 10.

(2) As shown in FIG. 9, both ends of the vertical plate-shaped portions 7 and 8 may be bent inwardly in an L shape. Further, as shown in FIG. 10, both ends of the vertical plate portions 7 and 8 may be bent outward.

[Advantage of the Invention] According to the present invention, it is possible to provide a chip-shaped varistor which is easy to manufacture. Moreover, since the facing portions of the first and second electrodes can be increased, it becomes possible to provide a chip-shaped varistor having a large surge resistance.

[Brief description of drawings]

1 is a partially cutaway perspective view of a chip varistor according to an embodiment of the present invention, FIG. 2 is a sectional view of the varistor of FIG. 1, and FIG. 3 is a perspective view showing the varistor element body of FIG. FIG. 4 is a perspective view showing the first and second external connection conductors of FIG. 1, FIG. 5 is a front view of the first and second external connection conductors, and FIG. 6 is a perspective view of the completed chip-shaped varistor. FIG. 7 is a front view of the varistor of FIG. 6, and FIGS. 8, 9 and 10 are sectional views showing modified examples of the first and second external connection conductors. 1 ... Varistor element body, 2 ... 1st electrode, 3 ... 2nd electrode, 4 ... 1st external connection conductor, 5 ... 2nd external connection conductor, 6 ... Insulation cover, 7, 8 ... Vertical plate-shaped part,
9, 10 ... Horizontal plate-like parts, 11, 12 ... Solder.

Claims (1)

[Scope of utility model registration request] 1. A plate-shaped varistor element body (1) having a substantially rectangular planar shape, and a first varistor element body (1) provided on one main surface of the varistor element body (1).
Electrode (2), and a second electrode provided on the other main surface of the varistor element body (1).
Electrode (3), a first outer connecting conductor (4) connected to the first electrode (2), and a second outer connecting conductor (5) connected to the second electrode (3). ) And a part of the varistor element body (1), the first and second electrodes (2) and (3), and the first and second external connection conductors (4) and (5). A chip-shaped varistor having an insulating cover (6) provided therein, the first plate-shaped portion (7) having a portion in which the first and second external connection conductors (4) and (5) extend vertically. ) (8) and second plate-shaped portions (9) and (10) each having a horizontally extending portion, and the second plate-shaped portions (9) and (10) are the first plate-shaped portions. A portion extending substantially at a right angle from the first plate-shaped portion (7) (8) between one end and the other end of the portion (7) (8), and the first outer portion Second plate-like portion (9) of the partial connection conductor (4)
Is arranged so as to be in contact with the first electrode (2), and is connected to at least a part of the first electrode (2) with solder (11), the first external connection conductor First plate-like portion (7) of (4)
Are arranged parallel to one side surface of the varistor element body (1), and the second plate-shaped portion (1) of the second external connection conductor (5) is
0) is arranged so as to be in contact with the second electrode (3), and is connected to at least a part of the second electrode (3) with a solder (12), First plate-like portion (8) of the connecting conductor (5)
Is arranged so as to be parallel to the other side surface of the varistor element body (1) and to face the first plate-like portion (7) of the first external connection conductor (4), and the insulating coating ( 6) is provided on at least one main surface side of the varistor element body (1), and the first plate-shaped portion (7) of the first and second external connection conductors (4) and (5). (8) One end and the other end of (8) are exposed on one and the other main surfaces (6a) and (6b) of the insulating coating (6), respectively.