JPH10172801A - Positive thermistor - Google Patents

Abstract

(57) [Problem] To provide a positive temperature coefficient thermistor used for preventing dew condensation of a video cylinder and the like, in which heat conduction with a heat radiator is improved to enable processing of a sintered body. The purpose is to: SOLUTION: To obtain a sintered body having a two-layer structure obtained by laminating and firing a positive temperature coefficient thermistor material and an insulator material, thereby enabling processing of the sintered body and improving heat conduction with a radiator. Thus, a positive temperature coefficient thermistor is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive temperature coefficient thermistor used as a heater for preventing dew condensation on a video cylinder.

[0002]

2. Description of the Related Art In recent years, a positive temperature coefficient thermistor has been used as a constant temperature heating element utilizing its own automatic temperature control function.

A conventional PTC thermistor will be described below. FIG. 3 is a sectional view of a conventional PTC thermistor. In FIG. 3, reference numeral 1 denotes a sintered body of a positive temperature coefficient thermistor. 3 is an electrode. FIG. 4 is a sectional view of a PTC thermistor device using the PTC thermistor.
In FIG. 4, 1 is a sintered body of a positive temperature coefficient thermistor, 3 is an electrode, 4 is a lead wire, 6 is an insulating sheet, and 5 is a radiator.

The operation of the positive temperature coefficient thermistor constructed as described above will be described below.

First, an electrode 3 made of aluminum, copper metallikon, or the like is provided on the sintered body 1 of the positive temperature coefficient thermistor, and a counter electrode is provided on one surface of the sintered body 1 of the positive temperature coefficient thermistor, and the lead wire 4 is soldered to this electrode. And a voltage is applied through the lead wire 4. Since the positive temperature coefficient thermistor itself has a function as a heater, it radiates heat. The heat radiator 5 is attached for efficient heat radiation. In the case of a conductive heat radiator, an insulating sheet 6 is inserted between the heat radiator 5 and the sintered body 1 of the positive temperature coefficient thermistor.

[0006]

However, in the above-described conventional configuration, when the radiator 5 having a conductive load such as a metal is used, a short circuit occurs between the radiator 5 and the positive temperature coefficient thermistor, and the heat is generated. The insulating sheet 6 is required because the efficiency is deteriorated and a short circuit occurs. Heat radiator 5 on curved surface
When a positive temperature coefficient thermistor is attached to the
A gap is generated between the heat sink and the heat radiator 5, resulting in poor heat conduction efficiency.

In order to make the shape of the sintered body 1 of the positive temperature coefficient thermistor suitable for the heat radiator having a curved surface in order to improve the heat conduction efficiency with the heat radiator 5, the heat radiator 5 having a curved surface must be formed before molding. There is a method of preparing a molded body so as to match the shape of the sintered body 1. However, as the shape becomes more complicated, the dimensional accuracy of the sintered body 1 becomes worse. Further, the method of processing the plate-shaped sintered body 1 to match the shape of the radiator 5 has a problem that the resistance value of the positive temperature coefficient thermistor is changed.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a positive temperature coefficient thermistor capable of processing a sintered body for improving heat conduction between a positive temperature coefficient thermistor and a radiator. .

[0009]

In order to achieve this object, the positive temperature coefficient thermistor of the present invention has a two layer structure in which a positive temperature coefficient thermistor material and an insulator material are formed in two layers and fired.

[0010] With this configuration, the sintered body of the portion of the insulator material does not conduct electricity, and therefore substantially contributes to the characteristics of the sintered body of the portion of the positive temperature coefficient thermistor material. Therefore, the conventionally required insulating sheet can be removed, and even if the sintered body of the insulator material is processed, the characteristics of the PTC thermistor are not affected, so that a PTC thermistor with good heat dissipation and heat conduction efficiency can be obtained. be able to.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention has a configuration in which a positive temperature coefficient thermistor material and an insulator material are laminated and fired, so that the insulator sheet can be used even when used in combination with a radiator. This is unnecessary, and this insulator material can be processed so as to conform to the shape of the heat radiator, thereby improving the thermal conductivity.

According to a second aspect of the present invention, the insulator material is processed in accordance with the shape of the heat radiator when the positive temperature coefficient thermistor device is used, and a positive temperature coefficient thermistor device excellent in heat conductivity is realized. can do.

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 (a),
FIG. 1B is a cross-sectional view of a positive temperature coefficient thermistor according to an embodiment of the present invention, wherein FIG. In FIG. 1, 11 is a sintered body of a positive temperature coefficient thermistor material, 12 is a sintered body of an insulator material, and 13 is an electrode. Here, the positive temperature coefficient thermistor of the present invention was prepared as follows. First, the basic formula of the material composition used in this embodiment is shown below. Equation (1) is a positive temperature coefficient thermistor material,
Equation (2) is a basic equation for the insulator material.

Ba _0.80 Sr _0.2 TiO ₃ + 0.024SiO ₂ + 0.0022Y ₂ O ₃ + 0.0006Mn (NO ₃ ) ₂ ... (1) Ba _0.80 Sr _0.2 TiO ₃ + 0.024SiO ₂ + 0.0006Mn (NO ₃ ) ₂ (2) respectively were weighed commercial high purity source such that the composition, mix placed in a pot mill lined with rubber with Menon boulder, dried, dry ingredients at 1160 ° C. in air 2 After calcining for a period of time, pulverizing and granulating, the pressure is 800 kg / cm so that each raw material becomes two layers using a hydraulic press.
Disc ² was laminated and formed into a disk shape, and baked in the air at 1320 ° C. for 2 hours to obtain a sintered body of a positive temperature coefficient thermistor.

Then, a sintered body 1 of the positive temperature coefficient thermistor material
On one side, an electrode 13 made of Al-Cu metallikon was provided so as to be a counter electrode. The characteristics of the thus obtained positive temperature coefficient thermistor before and after processing are shown by comparing the characteristics with those of the prior art thermistor (Table 1).

[0016]

[Table 1]

As is apparent from Table 1, the positive temperature coefficient thermistor according to the present embodiment has a point that the resistance value does not change even if the sintered body 12 of the insulating material is polished or the like. Excellent effects can be obtained.

As described above, according to the present embodiment, by providing the sintered body of the positive temperature coefficient thermistor with the sintered body 12 of the insulating material, the sintered body 12 of the insulating material can be used without changing the characteristics. It can be processed according to the application.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view of a PTC thermistor device using a PTC thermistor according to a second embodiment of the present invention. In FIG. 2, reference numeral 11 denotes a sintered body of a positive temperature coefficient thermistor material, 12 denotes a sintered body of an insulating material, and 13 denotes an electrode, which has the same configuration as that of FIG. 1 differs from the structure of FIG. 1 in that a lead wire 14 is soldered to an electrode 13 and attached to a conductive radiator 15 having a curved surface.
Is processed along the radiator 15.

The operation of the PTC thermistor configured as described above will be described below. First, the resistance between the electrode 13 and the radiator 15 was measured with a measuring instrument capable of measuring 100 MΩ, but the range was over and the insulation was insulated. Further, the surface temperature of the highest temperature part of the positive temperature coefficient thermistor device and the heat radiator 15 having the configuration of the conventional example was measured using a thermocouple. The results are shown in (Table 2).

[0021]

[Table 2]

As is clear from Table 2, the positive temperature coefficient thermistor according to the present embodiment can process a sintered body without using an insulating sheet, which was conventionally required. Accordingly, the sintered body 12 of the insulator material can be easily processed according to the above conditions, so that the adhesion between the radiator 15 and the thermistor with a positive temperature coefficient is improved, and the heat conduction efficiency is improved.

As described above, according to the present embodiment, by providing a sintered body of an insulating material in a positive temperature coefficient thermistor, an insulating sheet which is conventionally required is not required, and the heat conduction efficiency is improved. A positive temperature coefficient thermistor device can be obtained.

[0024]

As described above, the present invention does not require an insulating sheet by laminating a positive temperature coefficient thermistor material and an insulator material, and sintering the positive temperature coefficient thermistor to provide a sintered body of the insulator material. Also, an excellent positive temperature coefficient thermistor capable of processing without changing the characteristics of the element can be realized.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a PTC thermistor according to a first embodiment of the present invention before processing, and FIG. 1B is a cross-sectional view of the PTC thermistor according to the first embodiment after processing.

FIG. 2 is a sectional view of an apparatus using a positive temperature coefficient thermistor according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a conventional PTC thermistor;

FIG. 4 is a cross-sectional view of a device using a conventional PTC thermistor.

[Description of Signs] 11 Sintered body of PTC thermistor material 12 Sintered body of insulator material 13 Electrode 14 Lead wire 15 Heat radiator

Claims (2)

[Claims] 1. The method of claim 1, wherein the PTC thermistor material and the insulator material are two
Positive temperature coefficient thermistor formed and fired in layers. 2. The positive temperature coefficient thermistor according to claim 1, wherein the insulator material is processed to conform to the shape of the heat radiator when forming the positive temperature coefficient thermistor device.