JPH01235303A - Manufacture of glass-sealed thermistor - Google Patents

Abstract

PURPOSE:To airtightly seal a thermistor bare body having any coefficient of thermal expansion without being heated end in a free atmosphere by a method wherein two lead wires to which infrared ray absorbing glass beads have been welded are connected to counter electrode faces of the thermistor bare body from opposite directions and this thermistor bare body is covered with a transparent glass tube and is sealed airtightly after the glass bead parts have been irradiated with infrared rays and melted. CONSTITUTION:Lead wires 13a, 13b to which glass beads 14a, 14b composed of infrared ray absorbing glass have been welded from opposite directions are connected to both electrodes 12a, 12b of a thermistor bare body 11 where the electrodes 12a, 12b have been formed on opposite faces. The thermistor bare body 11 is covered with a glass tube 15 composed of lead glass in such a way that the tube touches the glass beads 14a, 14b; the beads are irradiated with infrared rays. By this setup, the glass beads 14a, 14b are heated and melted; they are welded to the glass tube 15; the thermistor bare body 11 is sealed airtightly. Since the glass is not welded directly to the thermistor bare body, the thermistor bare body having any coefficient of thermal expansion can be sealed with glass.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a glass-encapsulated thermistor that is used as a temperature sensor for home appliances, housing equipment, automobile equipment, etc., and is particularly useful in fields where high heat resistance is required. This relates to a manufacturing method.

BACKGROUND ART Conventionally, this type of glass-encapsulated thermistor, a finished product of which is shown in FIG. 2, has been manufactured by the following manufacturing method. In FIG. 2, reference numeral 1 denotes a thermistor element having electrodes 2a and 2b formed on opposing surfaces, and lead wires 3a and 3b are connected to the electrodes 2a on both surfaces.

After connecting from the direction opposite to 2b, the lead wire 31
．． This was a manufacturing method in which the entire part 3b, except for a part, was hermetically sealed by melting a glass tube 4 made of ordinary transparent glass.

Problems to be Solved by the Invention These conventional manufacturing methods have the following problems.

(1) Since the glass is welded to both the thermistor body and the lead wire, the thermal expansion coefficients of the thermistor body, lead wire, and glass must match, making selection of materials difficult.
It was a constraint. In particular, it has been difficult to change the coefficient of thermal expansion of the thermistor element.

(2) When sealing the thermistor element with λ, the molten glass is directly welded to the thermistor element, which causes the thermistor element to reach a high temperature and cause thermal deterioration in some cases.

(3) When the thermistor element is hermetically sealed, the lead wires also reach high temperatures and deteriorate due to oxidation, so it was necessary to control the atmosphere.

The present invention is intended to solve these problems.

Glass-encapsulated thermistors can use any thermistor element with any coefficient of thermal expansion, and the hermetic sealing of the thermistor element can be done in a free atmosphere without heating the thermistor element. The purpose of this invention is to provide a method for manufacturing.

Means for Solving the Problem In order to solve this problem, the method for manufacturing a glass-encapsulated thermistor of the present invention involves forming electrodes on opposite surfaces of a lead wire to which glass beads made of infrared absorbing glass are welded. After connecting the thermistor body from the opposite direction, a glass tube made of transparent glass is placed over the thermistor body and in contact with the two glass beads, and the glass beads are irradiated with infrared rays. The thermistor element is hermetically sealed by melting it with heat and welding it to the glass tube.

Effect: This manufacturing method allows the thermistor element with any coefficient of thermal expansion to be used, and the thermistor element can be hermetically sealed without heating the thermistor element.
Moreover, it can be carried out in a free atmosphere.

Therefore, it is possible to provide a method for manufacturing a glass-encapsulated thermistor with high reliability and productivity.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG.

First, the picture electrode 12+! of the thermistor element body 11 has electrodes 12a and 12b formed on opposing surfaces. L.

A lead wire 1 in which glass beads 142L and 14b made of infrared absorbing glass are welded to 12b from opposite directions.
Connect 3a and 13b. Thereafter, the thermistor body 11 is covered with a glass tube 16 made of ordinary lead glass, and the glass beads 14a are covered.

The thermistor body 1 is hermetically sealed by covering the glass beads 14 and 14b so as to contact them and irradiating them with infrared rays to generate heat and melt the glass beads 14 and 14b, and by welding them to the glass tube 16.

In this way, the glass-encapsulated thermistor shown in FIG. 1 was manufactured.

As described above, according to this embodiment, since the glass is not directly welded to the thermistor element, a thermistor element having any coefficient of thermal expansion can be used, and the thermistor element can be hermetically sealed. , only the glass beads are heated.

・Since the thermistor element is not heated, the thermistor element does not deteriorate. In addition, since the lead-out portion of the lead wire is sealed with glass in advance, airtight sealing can be performed in a free atmosphere. Therefore, it is possible to provide a method for manufacturing a glass-encapsulated thermistor with high reliability and productivity.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained, and the practical value thereof is great.

(1) Since the glass is not directly welded to the thermistor element, a thermistor element having any coefficient of thermal expansion can be used.

(2) When the thermistor element is hermetically sealed, the thermistor element is not directly exposed to high temperatures and does not deteriorate;
High reliability can be obtained.

(3) When the thermistor body is hermetically sealed, no matter what kind of atmosphere it is in, since the lead-out portion of the lead wire is sealed in advance, it will not deteriorate and the airtightness will not be impaired.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a glass-filled thermistor obtained by a method according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional glass-filled thermistor. 11...Thermistor element, 12a, 12b...
...electrode, 13a, 13b-lead wire, 14
! L. 14b...Glass beads, 16...Glass tube. Name of agent: Patent attorney Toshio Nakao and 1 other person//
---Boo ξ Nuku element' ne/2a, /2b--Identical name tXl, t3b-! / -y class l pet 4b---Glass Shi'-Spa Figure 2

Claims (1)

[Claims] After connecting lead wires with glass beads made of infrared absorbing glass welded to both electrode surfaces of the thermistor element body, which has electrodes formed on opposing surfaces, respectively, a glass tube made of transparent glass is connected to the thermistor element body. and cover the two glass beads so as to contact them, and then irradiate with infrared rays to melt the glass beads with heat, and weld them to the glass tube to hermetically seal the thermistor element. A method for manufacturing a glass-encapsulated thermistor, characterized in that: