JPH025505A - Voltage non-linear resistor - Google Patents

Abstract

PURPOSE:To prevent the discharge between lead wires and an element by a method wherein a high resistant layer is partially formed on the element to prevent the contact between the lead wires led out of an electrode formed on both sides of the element comprising a ceramic material and the element part not formed of the electrode from occurring. CONSTITUTION:Sb2O3, Bi2O3, etc., are added to ZnO to be mixed all together and formed into grains. The grains are formed and baked to produce an element. Next, the element is coated with Si-Sb-Bi base glass paste and backed to form a high resistant layer 4. Both the sides of the sintered body is coated with an electrode 2 and baked and then the produced element is held by lead wires 3 and coated with flux to be dipped in eutectic solder. Later, the element, after cleaning up with an organic solvent and drying up, is coated with an epoxy resin to manufacture the title voltage non-linear resistor 1. Through these procedures, the discharge between the lead wires 3 and the element 1 can be prevented from ocurring by partially forming a high resistant layer 4 on the element 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a voltage nonlinear resistor whose main component is zinc oxide, which has a high resistance layer formed on a five-ceramic element body.

(Prior art) Voltage nonlinear resistors whose main component is zinc oxide have excellent nonlinear voltage-current characteristics comparable to Zener diodes and large withstand current characteristics, so they are useful for voltage stabilization and pulse voltage suppression. It has been widely used for surge voltage absorption and lightning arrester applications. However, voltage nonlinear resistors whose main component is zinc oxide are used in 6 large current regions.1. In this case, flashover occurs in the creeping surface of the element alone, causing deterioration and destruction of the element. In addition, a voltage nonlinear resistor whose main component is zinc oxide has poor moisture resistance, so it is difficult to use it as a single element. Therefore, a method has been adopted in which the element body to which the lead wires are soldered is coated with an insulating material such as epoxy resin.

FIG. 2 shows a conventional voltage nonlinear resistor having zinc oxide as the JE component. In the figure, ] is a voltage nonlinear resistance element, 2 is an electrode, and :( is a lead wire.

(Problems to be Solved by the Invention) As described above, by coating with an insulator, flashover along the surface can be suppressed. However, in the case of an element with a high varistor voltage, a discharge occurs at the part where the lead wire and the element are in contact, sometimes destroying the resin.7 This is because the current density inside the element is uneven. 8 In other words, the current density tends to be lower around the electrodes, especially at the edges, than between the electrodes.
There is work. Therefore, there is a drawback that a potential difference occurs between the lead wire and the edge of the element body, which have the same potential as that between the electrodes, causing discharge. Even if a discharge occurs between the lead wire and the element body, it is to provide a 1i pressure surface linear resistance that does not cause τ. (The Ir'i body is formed on both sides of the cable body made of ceramic, and is placed on the surface of the element body in order to prevent the lead wire drawn out from the electrode from coming into contact with the part where the electrode is not formed. The main component is zinc oxide with a partially formed high-resistance layer.

(Function) According to the configuration of the present invention, an insulating layer is formed between the lead wire and the element body, and it is possible to prevent IF from discharging.

(Example) An embodiment of the present invention will be described based on FIG.

Figure 1 shows a voltage non-linear resistor made of zinc oxide as a main component according to the present invention.6 In the same figure -C5 The same parts as those of the conventional example shown in Figure 2 are given the same reference numerals and their explanations are omitted. do.

ZnO to sb2o-Ig f3120i # Co, 0
31 MnO,t Cr,Q, I NlO+Sin,
, AQ, 1, etc. were added, mixed for 20 hours in a 5-ball mill, dried, and then granulated using polyvinyl alcohol. 100℃/h, 1100℃~1300
Baked for 2 hours at a temperature of °C, the varistor voltage V, mA =
5i-Sb-Bi glass paste was applied as shown in FIG.

Baking was performed at a temperature increase/decrease rate of 300°C/h, 500°C, 10mj, n.

A high resistance layer 4 is formed. Finally, electrodes 2 are placed on both sides of the sintered body.
is applied and baked at 800°C to 900°C. The element thus obtained is sandwiched between lead wires 3, flux is applied, and the element is dipped in eutectic point solder L:'.

Thereafter, after washing with an organic solvent and drying, it is coated with an epoxy resin and cured by heating at 150° C. for 2 hours to obtain a voltage nonlinear resistance element 1.

The table shows the results of resin destruction due to discharge of the element in a surge resistance test conducted using the above element. Note that the surge test here refers to a test in which a standard waveform impulse current of 8720 flsec was caused to flow in a step-up manner.

FIG. 2 is a front view of a conventional voltage nonlinear resistor.

1... Voltage nonlinear resistance element, 2... Electrode, 3...
・Lead wire, 4...High resistance layer.

Patent applicant: Matsushita Electric Industrial Co., Ltd.: As can be seen from the table of surge current application times, the product of the present invention has a power consumption of 15,000 (A
/d) 6 (Effects of the Invention) According to the present invention, in order to prevent contact between the lead wire and the element body, by forming a high resistance layer partially on the element body, It is possible to prevent electrical discharge between the lead wire and the element body, which has a great practical effect.

46 Simple drawing! +4 Una explanation

Claims (1)

[Claims] A high-resistance layer is partially formed on the element body to prevent contact between lead wires pulled out from electrodes formed on both sides of the element body made of ceramic material and parts of the element body where no electrodes are formed. Non-linear resistor.