JPS63172403A - Negative characteristic thermistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negative characteristic thermistor used as a temperature sensing element.

Conventional negative characteristic thermistors are made by sintering raw material powder into a plate shape and forming electrodes on both sides of the thermistor body. One end of the lead terminal is temporarily fixed to the electrode with conductive paste. The entire thermistor body including a part is covered with an exterior material. Glass is generally used as the exterior material to ensure high-temperature use and mechanical strength.

By the way, if glass is used as the exterior material, a noble metal conductive paste with a higher melting point than glass must be used for temporarily fixing the electrode and lead terminal, which can be expensive. There's a problem.

Another problem is that the conductive paste must be applied to the lead terminals, connected to the electrodes of the small thermistor, and then dried, which takes time and reduces work efficiency.

The present invention was made in view of these problems, and an object of the present invention is to provide a negative characteristic thermistor that can be easily manufactured in a short period of time.

In order to achieve the above object, the present invention includes electrodes formed on both sides of a thermistor body, a pair of lead terminals welded to the electrodes, and a pair of lead terminals connected to the whole thermistor body and one of the lead terminals. It is characterized in that the portion is covered with an exterior material.

According to the above, since the lead terminals' and the electrodes are connected without using a noble metal conductive paste, the manufacturing process of the negative characteristic thermistor is simplified without requiring much time and effort for connection, and the price is also reduced.

Figure 1 is a sectional view showing a negative characteristic thermistor as an embodiment of the present invention.
The thermistor element body 1 is made of a transition metal oxide such as nickel, and electrodes 2.3 made of, for example, gold, silver, platinum, etc. are formed on both sides of the thermistor element body 1. 4 and 5 are lead terminals made of, for example, Dumet wire, and in this embodiment, the lead terminals 4.5 and the electrodes are connected by welding. There are various welding methods such as resistance welding and arc welding, which will be discussed later.

A part of the lead terminal 4.5 and the entire thermistor body 1 are covered with an exterior material 6 made of glass, for example.

Next, an example of a method for manufacturing the above-mentioned negative characteristic thermistor will be described.For example, a plate-shaped thermistor element having a diameter of 20 to 50 mm, 11 thickness of 5 to 30 mm is fired, and the plate-shaped thermistor element is sliced, etc. A wafer-shaped thermistor body having a thickness of 0.2 to 1.0 mm is formed. An electrode paste containing, for example, gold, silver, or platinum as a main component is applied to both sides of this wafer-shaped thermistor body, and after the electrode paste is dried, the electrodes 2 and 3 are formed by baking. After forming the electrodes, this wafer-shaped thermistor body is guised to a temperature of, for example, 0°5 ++
A thermistor body 1 having an n-angle front and rear wrap shape is produced. For example, a diameter of 0.0 mm is formed on both sides of the obtained chip-shaped thermistor element L.
1 to 0.3n+ Dumet wires 4°5 are connected, for example, by resistance welding as follows.

That is, as shown in FIG. 2, one end of the Dumet wire 4 is placed on one electrode 2 of the thermistor body 1, the first welding electrode 7 is placed on the Dumet wire 4, and the Dumet wire 4 is At the same time, the second welding electrode 8 is placed on the electrode 2, and a current is passed between the welding electrodes 7.8.As the current flows between the welding electrodes 7.8, the heat capacity is small and the contact resistance is low. Joule heat is generated between the large dumet wire 4 and the electrode 2, and the dumet wire 4 is partially melted and connected to the electrode 2. Next, connect the Dumet wire 5 to the electrode 3 in the same manner as shown in FIG.
The main body is inserted into a glass enclosing jig consisting of a glass enclosure, covered with a short tubular glass 6, and the carbon heater 9 is energized to heat and melt the glass 6, thereby covering the exterior with the glass 6.

In the above embodiment, a negative characteristic thermistor whose exterior material is made of glass is shown, but the exterior material is not limited to glass, and may be resin.

1 Ri ■Suko According to the negative characteristic thermistor of the present invention, no special bonding material or complicated work is required to bond the lead terminal and the electrode, so manufacturing is easy and can be done in a short time. This has the effect of making it possible to carry out the manufacturing process, and also has the effect of reducing manufacturing costs.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a negative temperature thermistor showing an embodiment of the present invention, Fig. 2 is a view showing how the lead terminal is connected to an electrode, and Fig. 3 is a view showing how the negative temperature thermistor is installed in a glass enclosure jig. It is a figure which shows the state when it is inserted. 1... Thermistor element body, 2.3... Electrode, 4.5.
... Lead terminal, 6... Exterior material. Patent applicant 2 Murata Manufacturing Co., Ltd. Figure 1 Figure 3

Claims (1)

[Claims] A negative characteristic thermistor comprising electrodes formed on both sides of a thermistor body, a pair of lead terminals welded to the electrodes, and the entire thermistor body and a portion of the lead terminals covered with an exterior material.