JPS58216402A - Lead wire for 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] [Technical field of invention] The present invention relates to a lead wire for a thermistor.

[Technical background of the invention and problems with the background art] Thermistor is generally used as a sensor for temperature adjustment, and as shown in Figure 1, it is made by molding and sintering a certain type of metal oxide powder with a broken glass coating (1). Connect the internal lead wire (31) to the semiconductor (2), which has a large temperature coefficient of electrical resistance, and then connect the glass-sealed metal wire (4) connected to the internal lead wire (3) to the glass-sealed part (31). 1a) is hermetically passed through and led out to the outside, and the glass-sealed metal wire (4) is a Dumet wire with excellent glass-sealing properties.The thermistor sensor formed in this way is, for example, When used in a fan heater, it is exposed to the atmosphere at approximately 300°C to 600'C for a long time, so the Dumet wire, which is a glass-sealed metal wire (4) led out from the glass coating, is the outermost part of the wire. The borax layer that forms the surface is eroded by the heat.

Furthermore, the surface of the internal copper layer comes in contact with the high temperature air, resulting in suboxide steel Cu! The oxidized steel is oxidized from zero to copper oxide, CuO, and eventually this oxidized steel peels off, the wire diameter gradually decreases, and it is often seen that the wire eventually breaks due to external stress such as vibration. Further, as described above, when the wire diameter is reduced and the same voltage is applied, the electrical resistance increases and heat is generated, which changes the characteristics of the semiconductor and causes a deviation in temperature adjustment.

In response to this, the present inventors previously proposed the use of a heat-resistant and oxidation-resistant nickel-plated steel-coated iron-nickel alloy wire instead of the Dumet wire as the glass-sealed metal wire (4). According to this proposal, there was a remarkable effect on thinning of the wire diameter and breakage accidents due to oxidation of the glass-sealed metal wire (4), but regarding the airtight sealing with the glass coating,
In fact, it tends to be slightly inferior to the conventional Dumet wire, and further improvements have been desired.

[Purpose of the invention]

The present invention provides a lead wire for a thermistor that, when applied to a thermistor, is resistant to oxidation and disconnection even when exposed to high temperatures in the atmosphere for a long time, and has excellent airtight sealing properties with a glass coating. With the goal.

[Summary of the invention]

The lead wire for a thermistor of the present invention is characterized by comprising a Dumet wire and a nickel-A [[[[[] or nickel-coated composite wire] connected to one end of the Dumet wire, and the Dumet wire portion is made of glass of the glass coating of the thermistor. If used in the sealing part or as an external lead wire led out from the glass sealing part, the nickel wire Otake nickel coated composite wire will have excellent airtight sealing properties with the glass, and will also work well even when used at high temperatures. Due to its oxidation resistance, disconnection accidents can be greatly reduced.

[Embodiments of the invention]

The details of the invention will be explained below with reference to the illustrated embodiments. FIG. 2 shows a longitudinal cross-sectional view of a thermistor using a lead wire (5) for a star according to the present invention.

(1) is a glass coating made of soft glass, (2) is a semiconductor made of a metal oxide sintered body, (3H31 is an internal lead wire whose one end is connected to the semiconductor (2)),
(5) is the thermistor lead wire, which is a Dumet wire (5a)
and a nickel-coated composite wire (5b) section connected thereto. The above Dumet wire (5a) is used as a glass-sealed metal wire in the glass sealing part, and also as a nickel-coated composite wire (5b).
) is used as an external lead wire.

〔Effect of the invention〕

According to the above configuration, the glass sealing metal wire that is airtightly sealed to the glass in the glass sealing part (1a) is a Dumet wire (58) whose coefficient of thermal expansion is similar to that of the glass, so that the airtightness is extremely high. It is possible to prevent air from entering the glass coating through the glass sealing part and deteriorating the characteristics of the semiconductor.

On the other hand, when the Thermosta is used with a temperature adjustment sensor such as a fan heater, even if the external lead wire is exposed to high temperatures in the atmosphere for a long time, the external lead wire is made of a heat-resistant nickel-coated composite wire (5b). Therefore, the risk of wire breakage due to oxidation can be extremely reduced, and changes in characteristics due to thinning of the wire diameter can be significantly reduced.

The following table shows a thermistor lead wire using a single Dumet wire (conventional example 1) with the glass sealing part and external lead wire listed in 1 to 1 as the conventional example, and the same (conventional example with glass sealing part and external lead wire) A thermistor using a single nickel-plated steel coated iron-nickel alloy wire as the external lead wire (conventional example 2) and the thermistor lead wire of the present invention are incorporated as a sensor for temperature adjustment of a fan heater.

This shows the results of a 2,000 hour practical test.

Note that (Invention 1) uses a copper-coated iron-nickel alloy wire plated with nickel as a nickel-coated composite wire, and (Invention 2) uses an iron core metal wire plated with nickel.

As is clear from the table 9, compared to conventional thermistor lead wires of the present invention, the defective rate can be significantly reduced when glass sealing defects and disconnection defects are taken into account. I understand.

The effect is extremely remarkable.

In the above embodiment, a nickel-coated composite wire is used for the external lead wire portion, but the same effect can be obtained even if a nickel wire is used. However, in this case, the cost will be relatively high.

[Brief explanation of drawings]

Is Figure 1 a conventional thermistor lead wire? A vertical cross-sectional view of the thermistor used, Figure @2 is a vertical cross-sectional view of a thermistor using a thermistor lead wire according to an embodiment of the present invention. (1)...Glass coating, (2)...Semiconductor (3)...Internal lead wire 5 (5)...Lead wire for thermistor (5a)...Dumet wire, ( 5b
)...Nickel-coated composite wire (7317) Agent
Patent Attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2

Claims (1)

[Claims] A lead wire for a thermistor comprising a Dumet wire and a nickel wire or a nickel-coated composite wire connected to one end of the Dumet wire.