JP2000150205A - Voltage non-linear resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a voltage non-linear resistor at low cost with high reliability and without complicated production process by forming a weak spot having a fuse function in at least one lead wire and strengthening the weak spot with an insulating strengthening material. SOLUTION: A silver electrode 2 with about ϕ8 is printed and burned with a margin about ϕ2 on both surfaces of a sinter 1 with about ϕ10 at about 1200 deg.C, which includes zinc oxide as a principal component and magnesium oxide, bismuth oxide, cobalt oxide and the like as the other component. In addition, a notch 5 with about ϕ0.3 thickness and about 0.5 mm length is provided as a weak spot on one surface, and a lead wire 3 which has ϕ0.8 and in which the notch 5 is covered with an insulating tube 6 is soldered to the electrode 2 and coated with an encapsulating resin 4, thereby producing a varistor with a protective mechanism of varistor voltage 220 V. The sinter 1 with the varistor mechanism, the electrode 2 and the encapsulating resin 4 can be optionally selected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a voltage non-linear resistor having a security function.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional voltage non-linear resistor (hereinafter referred to as a varistor) has electrodes 2 formed on both sides of a sintered body 1, and a lead wire 3 is soldered to the electrodes 2. And a resin exterior 4. When an overvoltage or an excessive surge is applied to such a varistor, the varistor is destroyed and short-circuited. If the current from the power supply circuit continues to flow, the varistor generates heat and may be ignited in some cases. Although a fuse is provided on the circuit to prevent such a problem, it is difficult to provide an appropriate fuse depending on the load current of the circuit in some cases.

[0003] A varistor is combined with an appropriate fuse,
In order to prevent the risk of fire when the varistor is destroyed, various proposals have been made in the past in which the varistor and the fuse are integrated and the varistor itself has a security function. For example, in JP-A-2-47842,
Japanese Patent Application Laid-Open No. 9-129403 discloses a technique in which a two-part flat electrode is connected to a crossover electrode made of a narrow and easily soluble metal provided on a heat-resistant insulating layer to provide a security function. A technique has been proposed in which a lead wire formed and provided thereon and an electrode of a varistor element are connected by a fuse acting body.

[0004]

However, such a conventional technique has a problem in that the manufacturing process is complicated in order to provide a security function to the varistor, and thus the cost is increased.

[0005]

In order to solve the above-mentioned problems, in the varistor according to the first aspect, electrodes are provided on both surfaces of the sintered body, and lead wires are drawn out from the electrodes on both surfaces of the varistor. In a varistor in which the body is covered with a resin, at least one of the lead wires has a weak point having a fuse function, and the weak point is reinforced with an insulating reinforcing material.

According to the varistor according to the present invention, electrodes are provided on both surfaces of the sintered body, lead wires are drawn out from the electrodes on both surfaces, and at least one of the lead wires is included in the varistor in which the sintered body is covered with a resin. A simple structure in which a weak point having a fuse function is formed and the weak point is reinforced with an insulating reinforcing material provides a security function that the lead wire is blown before the varistor generates heat or fires. Therefore, a complicated manufacturing process is not required, and a low-cost and highly reliable varistor can be provided. In addition, reinforcement of the weak part of the lead wire is covered with insulating resin, reinforced with insulating material,
Various methods, such as covering with an insulating tube, can be considered, but it is sufficient that the weak portion having the fuse function has sufficient strength to withstand practical use.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A varistor according to the present invention is manufactured as follows as an example. Silver electrodes are printed on both sides of a sintered body containing zinc oxide as a main component with a margin, and formed by firing. Further, a normal lead wire is soldered to one of the electrodes, and a weak portion is provided to one of the electrodes, and a lead wire having the weak portion covered with an insulating tube is soldered. The exterior is coated with epoxy resin to produce a varistor with a security function.

According to the varistor with a security function manufactured as described above, when a large current flows, the weak portion acts as a fuse and the lead wire is blown. As a result, a highly reliable varistor can be provided.

Further, since the weak point is reinforced by a tube as a reinforcing material, the strength of the lead wire does not matter.

A specific embodiment will be described below with reference to the drawings. Here, FIGS. 1 and 3 are structural views of the present invention, and FIGS.
4 is an enlarged cross-sectional view of the weak portion A of the lead wire.

[0011]

Embodiment 1 As shown in FIGS. 1 and 2, a φ10 silver body having zinc oxide as a main component and magnesium oxide, bismuth oxide, cobalt oxide, etc., was added to both sides of a φ10 sintered body 1 with margins. Electrode 2 was printed and fired at 1200 ° C.
Further, one of the weak points has a thickness of φ0.3 and a length of 0.5.
The lead wire 3 of 0.8 mm, in which the cut portion 5 is covered with an insulating tube 6, is soldered to the electrode 2, coated with an exterior resin 4, and provided with a varistor voltage 2.
A varistor with a security function of 20 V was manufactured.

[0012]

Embodiment 2 As shown in FIGS. 3 and 4, a φ10 silver body containing zinc oxide as a main component and magnesium oxide, bismuth oxide, cobalt oxide and the like is added to both sides of a φ10 sintered body 1 with a margin. Electrode 2 was printed and fired at 1200 ° C.
Further, one of the weak points is a thickness φ0.3 and a length 0.5.
The notch 5 is provided with a notch 5, and the notch 5 is reinforced with an insulating resin 7. A lead wire 3 having a diameter of 0.8 is soldered to the electrode 2, coated with an exterior resin 4, and a varistor voltage 220 is applied.
A varistor with a security function of V was manufactured.

According to the methods of Examples 1 and 2, 20 varistors each having a security function were manufactured, and when 220 V AC was applied, the security was examined. As a result, all the varistors were open and the effectiveness of the security function was confirmed.

In the present invention, a sintered body having a varistor function, an electrode, and an exterior resin can be appropriately selected, and it goes without saying that the present invention has the same effect in any case.

[0015]

As described above, according to the present invention, a highly reliable varistor with a security function can be provided without requiring a complicated manufacturing process.

[Brief description of the drawings]

FIG. 1 is a structural diagram in which a weak portion A of a lead wire is reinforced with a tube.

FIG. 2 is an enlarged cross-sectional view in which a weak portion A of a lead wire is reinforced with a tube.

FIG. 3 is a structural diagram in which a weak portion A of a lead wire is reinforced with an insulating resin.

FIG. 4 is an enlarged cross-sectional view in which a weak portion A of a lead wire is reinforced with an insulating resin.

FIG. 5 is a structural view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sintered body 2 Electrode 3 Lead wire 4 Outer resin 5 Notch 6 Insulating tube 7 Insulating resin

Claims (1)

[Claims] An electrode is provided on both surfaces of a sintered body, and lead wires are drawn out of the electrodes on both surfaces of the sintered body. Forming a weak point having a fuse function,
A voltage non-linear resistor, wherein the weak point is reinforced with an insulating reinforcing material.