JPS6313301A - 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 Field of Industrial Application The present invention relates to a thermistor as a temperature sensor used in household electrical appliances such as electric openers and microwave ovens, and sanitary appliances such as toilet seats with hot water cleaners.

Prior Art Thermistors have traditionally been used as temperature sensors. Thermistors are manganese and cobalt.

The heat-sensitive element is a composite oxide obtained by firing a transition metal such as iron or copper. As shown in FIGS. 3 and 4, thermistors include bead-type, diode-type, etc. depending on the shape and manufacturing method. The bead type has a corrosion-resistant lead-out body 4 joined to Dumet #B attached as electrodes on both sides of the heat-sensitive element 1. A part of the drawer body 4 and the heat-sensitive element 1 are wrapped in an insulator 5 made of glass, heat-resistant resin, or the like. In general, Dumet wire or CPIs, which have copper cladding on the surface of iron, are often used for the four drawer bodies, which closely match the thermal expansion of glass. Furthermore, in order to prevent local electrolytic corrosion at the joint between the drawer body 4 and the Dumet wire 6, the insulator 5 is covered with silicone, epoxy, polyimide resin enamel or low melting point borosilicate glass paste. A sealing material 7 is provided.

On the other hand, the diode type has thick film electrodes 3 made of gold, silver, palladium, etc. printed and baked on both sides of the heat sensitive element 1, and a corrosion-resistant drawer body 4 is similarly attached to the dumet ls that is bonded or crimped to this thick film electrode 3. After that, like the bead shape, there is an insulator 5.
It is covered with a sealing material 7.

According to the above configuration that the invention seeks to solve, among household electrical appliances, electric openers, microwave ovens, open ranges, etc. have an internal temperature of 30%.
It is necessary to control the temperature change to ~260°C and at the same time quickly catch the rapid temperature rise of the gas. In addition, because food is heated, baked, or steamed, food particles are likely to adhere to it, and water vapor in the refrigerator may condense, causing a portion of the temperature sensor to be easily damaged. Therefore, in order to prevent the thermal response from worsening, it is coated with a heat-resistant enamel such as Noricon resin.

However, in reality, the enamel film is not completely coated on the thin Siemeno wire 6 of the thermistor or on the sharp edges of the cut portion of the wire.

Ushita. The resistance value of a thermistor changes depending on the temperature.

In order to capture the degree of change, a voltage is applied to both ends of the wire 60 of the thermistor.

This applied voltage depends on the configuration of the temperature control circuit.

Due to the noise and ease of assembling the 9 malfunctioning circuits.

Generally, it is 3-5V DC.

If food containing salt or water droplets adhere to the surface of the thermistor under such conditions.

At the same time as the surface resistance decreases significantly, electricity bypasses the heat-sensitive element 1 and a shunt current of electricity occurs between the Dumet wires B on both sides.

Therefore, the constituent material of Zimet wire Otsu dissolves into water droplets as metal ions through the pinholes in the surface enamel coat. This electrolytic corrosion phenomenon of metal is caused by heat-sensitive element 1.
This occurs on the side where the voltage is applied to the anode through the circuit, and the wire eventually breaks, making the temperature control circuit inoperable. There is a problem in that the higher the applied voltage, the faster the speed of electrolytic corrosion disconnection.

Means for Solving the Problems The present invention has been made to solve the above problems, and the thermistor drawer body is made of metal titanium, titanium and nickel, or titanium and palladium, which is less prone to electrolytic corrosion. It uses an alloy of

Function: Due to the above structure, titanium metal and alloys of nickel and palladium mainly composed of titanium exhibit excellent edibility even in highly concentrated saline solutions. In addition, even if a voltage is applied to both ends of a drawer made of these metals, a dense titanium oxide is formed on the surface of the metal, which becomes passivated and prevents corrosion, and at the same time becomes a non-conductive film. Electricity splitting will no longer occur.

Example An embodiment of the present invention will be described below with reference to the drawings.

The configuration of the embodiment is as shown in FIGS. 1 and 2,
Figure 1 is a bead shape, Figure 2 is! 71: Shows a cross section of a diode-shaped thermistor.

Reference numeral 1 denotes a heat-sensitive element, which is a composite oxide obtained by sintering an arsenic acid of a transition metal such as manganese, cobalt, iron, or copper at a temperature of about 1200 to 1600°C. The bead type shown in FIG. 1 has platinum wires 2 attached as electrical wires on both sides of the heat-sensitive element 1. The diode type shown in Fig. 2 is connected to both Uj of the heat-sensitive element 1.
jl H is printed with a thick film electrode 53 made of gold, silver, palladium, etc. The 1st half is an art piece. Reference numeral 4 denotes a drawer body, in which the electrodes are made of platinum, the fitting 2, the thick electrode 6, and the electrodes are made of titanium, titanium and nickel.

This corrosion-resistant drawer body 4 made of an alloy of titanium, palladium, etc. is bonded or crimped and fixed. 5 is a sealing body made of lead silicate glass, heat-resistant polyimide, epoxy resin, etc., like the conventional insulator 5, and includes the heat-sensitive element 1 and a part of the corrosive drawer body 4. ,
Electricity, insulation and fixing.

The operation of this embodiment having the above configuration will be explained below.

FIG. 5 is a diagram showing the relationship between applied voltage and current density.

The metal titanium wire of the present invention and the conventional Siemenoto wire were used as electrodes, immersed in 3% saline solution, and a DC voltage of 0 to 5 V was applied, and the current flowing at that time was set to a constant ratio of 61. , the conventional Jimenoto@ is 1. When it exceeds OV, the current rapidly decreases and increases, and as a result, the positive side gradually dissolves, but the current is 25 to 3 V for the Kaneda titanium of the present invention and the wire type.
Electrolysis of saline water occurs between the two, causing a somewhat large current to flow, and beyond that, polarization occurs and only a slight current flows even at 5V. This is because metallic titanium is a metal that is easily oxidized and forms an extremely dense oxide film on one surface. Further, the oxide film formed on the surface is not easily reduced. Therefore, it becomes metal ions and is difficult to dissolve.

Therefore, it is also effective to provide the corrosion-resistant drawer 4 only on one side and configure the other side with the wire 6. In this case, the anode side of the potential to be applied is set as the corrosion-resistant lead-out body 4, and the cathode side is set so as to be the Siemeno wire 6. On the other hand, cents.

A small amount of current may flow and the wire 6 may corrode.

Effects of the Invention According to the present invention, electrolytic corrosion can be prevented by using titanium or a titanium alloy mainly composed of titanium as a corrosion-resistant drawer.

It is possible to provide a long-life thermistor that can be used even in environments with high moisture or salt content. This effect is caused not only by the thermistor, but also by applying direct current voltage through a high-resistance element.
It has the advantage of being applicable to drawers for electronic components used in humid environments.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a thermistor (bead type) showing an embodiment of the present invention, Fig. 2 is a cross-sectional view of the thermistor (diode type), and Fig. 3 is a cross-sectional view of a conventional thermistor. (
4 is a cross-sectional view of the thermistor (diode type), and FIG. 5 is a comparative correlation diagram of applied voltage and current density of the thermistor of the present invention and a conventional thermistor. 1... Heat sensitive element, 2... Platinum wire. 3. Thick film electrode, 4. Extraction body. 5... Sealing body.

Claims (1)

[Claims] Electrodes consisting of platinum wires (2) or thick film electrodes (3) connected to both ends of the heat-sensitive element (1) and a drawer body for power supply (4)
), and a thermistor using titanium, an alloy of titanium and nickel, or an alloy of titanium and palladium for the drawer body (4) of the thermistor, which is formed by fixing the heat-sensitive element (1) and the sealing body (5). .