JPH0650822A - Contact type thermistor - Google Patents

Abstract

PURPOSE:To provide a contact type thermistor having high resistance to heat and high-speed response by constructing it of a plate-shaped metal support having a recess in the central part and of a temperature detector disposed in the recession. CONSTITUTION:A recess 61 is provided in the central part of a plate-shaped metal support 6 and a temperature detector 7 is disposed in this recess 61. A stainless steel plate is used for the support 6. The detector 7 is constructed by disposing a thin film thermistor element 71 on an alumina support 72 and then by covering the periphery of the element with glass 73. The element 71 is constructed by forming an electrode film and a temperature-sensitive resistor film on the surface of an alumina substrate and lead wires 74 and 74' are led out of the electrode film. No organic substance such as resin is used in this constitution and, therefore, resistance to heat of 200 deg. or above is obtained. When a thermistor 6 thus constructed is brought into contact with an object, a heat flow occurs in a concentrated manner through the recess 61 of a small area and, therefore, heat response is high. The heat response of still higher speed is obtained by disposing a heat sinker between the inner surface of the recess 61 and the outer surface of the support 72.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface temperature sensor capable of detecting the surface temperature of an object by mechanically contacting the surface of the object, and more particularly to a contact type thin film thermistor which can be used at a high temperature of 200 ° C. or higher. It is a thing.

[0002]

2. Description of the Related Art Conventionally, a surface temperature sensor of this type is shown in FIG.
As shown in FIG. 2, the temperature detection element composed of the glass-sealed thermistor 1 is connected to the lead wires 2 and 2 ′, and the glass-sealed thermistor 1 is bonded to the metal plate 3 with the resin 4.
The metal plate 3 is mechanically brought into contact with the surface of the object by screwing or the like to detect the surface temperature. In addition,
The metal plate 3 usually has a mounting hole 5 or the like to the temperature-measured body. (For example, JP-A-60-1255345 and JP-A-60-125535)

[0003]

However, in the above configuration, the glass-sealed thermistor 1 is bonded to the metal plate 3 with the resin 4, and the heat resistant temperature of the resin 4 is usually about 200 ° C. or less. Therefore, there is a problem that the maximum operating temperature is limited to about 200 ° C. or less.

Further, the metal plate 3 has a mounting hole 5 for mounting a temperature measuring object, etc., and a part of the lead wires 2, 2'of the glass-sealed thermistor 1 are also bonded with a resin 4. Therefore, an area larger than the minimum area required for temperature measurement (only the area where the glass-sealed thermistor 1 is bonded) is required. For this reason, there has been a problem that the heat capacity of the temperature detector becomes unnecessarily large and the thermal response becomes slow.

The present invention solves the above-mentioned problems of the prior art, and an object of the present invention is to provide higher heat resistance and faster response than those of the prior art.

[0006]

In order to solve the above-mentioned problems, the present invention is provided with a structure comprising a plate-shaped metal support having a recess in the center and a temperature detector arranged in the recess.

[0007]

According to the present invention, since the organic material such as the resin is not used at all in the present invention, the maximum operating temperature becomes high. That is, a thermistor is usually used as the temperature detector, which is composed of a temperature-sensitive ceramic, a firing glass coating, or the like. Since these are formed through a high temperature firing step, higher heat resistance than ever can be easily obtained.

Further, the temperature detector is arranged in the recess of the metal support. The shape of this recess may be sufficient to accommodate the temperature detector and be of a minimum size. The outer surface of the small recess is adhered to the temperature-measured body, and only the peripheral portion of the temperature detector is heated or cooled, so that high-speed thermal response can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the contact type thermistor of the present invention when a thin film thermistor element is used as a detector. A recess 61 was provided in the center of the plate-shaped metal support 6, and the temperature detector 7 was placed in this recess 61. A stainless steel plate (thickness 0.5 mm) was used as the plate-shaped metal support 6, the diameter was 18 mm, and the recess 61 was 8 mm in diameter. The detector 7 is configured by disposing the thin film thermistor element 71 on the alumina support 72 and then covering the thin film thermistor element 71 with glass 73. The thin film thermistor element is constructed by forming an electrode film and a temperature sensitive resistor film on the surface of an alumina substrate.
It is omitted in FIG. Lead wires 74, 7 from electrode film
I took out 4 '.

In the contact type thin film thermistor structure of the present invention thus constituted, compared with the conventional example, since no organic substance such as resin is used, the maximum operating temperature is 20.
It can be higher than 0 ° C. That is, the thin film thermistor element 7
1, the alumina support 72, the glass 73, etc. are all inorganic substances and are formed through a firing process at 700 ° C. or higher, so that heat resistance at 200 ° C. or higher can be easily obtained. Therefore, the heat resistance of this example ultimately depends on the heat resistance of the temperature-sensitive resistor film. This heat resistance is determined by the material of the temperature sensitive resistor film and the forming conditions. There are various types of temperature-sensitive resistor films, such as composite metal oxides, vapor-deposited films of Ge, Si, SiC, etc., sputtered films, printed / fired thick films, among others, the SiC sputtered temperature-sensitive resistor film has a heat resistance of 500 ° C. And having resistance temperature specification suitable for detecting a wide temperature range of 0 to 500 ° C.

The contact type thermistor of this embodiment and the thermistor having the same structure except that the recess 61 and the outer peripheral portion 62 are formed on the same plane are brought into close contact with the surface of the object, and the 90% thermal response time is measured. As a result, the former is about 8se
c, the latter showed a thermal response of about 10 sec. When the contact type thermistor of this embodiment contacts an object, the heat flow intensively flows through the recess 61 having a small area, so that the thermal response becomes faster. On the other hand, the concave portion 61 and the outer peripheral portion 6
If 2 and 2 are formed on the same plane, the heat flow is dispersed and flows through the contact portion having a large area, so that the thermal response seems to be slow.

When a heat sinker is arranged between the inner surface of the recess 61 and the outer surface of the alumina support 72, 90
The% thermal response time was about 6 seconds, and further high-speed thermal response was obtained. This is because the thermal resistance between the recess 61 and the alumina support 72 is reduced. Further, it is desirable that the lead wires 74, 74 ′ be taken out in a direction perpendicular to the plate-shaped metal support 6. Since the temperature detector 7 is arranged in the recess 61, when the lead wires 74, 74 ′ are taken out in the direction parallel to the plate-shaped metal support 6, the lead wires 74, 7 ′ are formed.
This is because 4'may contact the outer peripheral portion 62 of the plate-shaped metal support 6. When it is necessary to fix the contact type thermistor of this embodiment to an object, a mounting hole may be provided in the outer peripheral portion 62 of the plate-shaped metal support.

In the embodiment of FIG. 1, the thin film thermistor element is used for explanation, but the same can be said for the temperature sensitive ceramic element. However, the temperature-sensitive ceramic element is generally cylindrical and has lead wires from both ends thereof, or disk-shaped and has lead wires from both sides thereof. For this reason, heat transfer between the flat plate-shaped insulating support 5 and the temperature-sensitive ceramic element becomes worse than that of the thin film thermistor element, so that the thermal response becomes slow. However, heat resistance of 200 ° C. or higher can be sufficiently ensured.

FIG. 2 shows another embodiment of the present invention. This embodiment is suitable when the object to be measured is different for each measurement. The temperature detector 7 was arranged in the recess 81 of the cylindrical metal container 8 having the recess 81 at the bottom and the plurality of catches 82 at the lower end. On the other hand, the cylindrical guide 9 having the overhanging portion 91 whose upper portion is formed to have a larger diameter than the lower portion is prepared, and the inner surface of the peripheral portion 83 of the bottom portion of the cylindrical metal container 8 and the cylindrical guide 9 are prepared.
The compressed spring 10 is arranged between the bottom surfaces 92 of the overhanging portions 91. The catch 82 of the cylindrical metal container 8 is located below the overhanging portion 91 of the cylindrical guide, and a small gap is provided between the cylindrical metal container 8 and the cylindrical guide 9. The cylindrical metal container 8 and the cylindrical guide 9 are mechanically coupled by a compressed spring 10 and a small gap is provided between them. Therefore, for example, when the cylindrical guide 9 is held by hand and the outer surface of the recess 81 is brought into contact with and pressed against the object, the cylindrical metal container 8 moves according to the pressing force and adheres to the object surface. . in this way,
In this embodiment, the cylindrical metal container 8 moves according to the pressing force and comes into close contact with the surface of the object, so that the surface temperature can be easily detected even when the object to be measured is different each time.

[0015]

As described above, according to the present invention, the following effects can be obtained.

(1) Since it does not contain the resin used in the conventional surface temperature sensor at all and is made of an inorganic material such as ceramics and sintered bodies, it has excellent high heat resistance.

(2) Since the temperature detector is arranged in the recess of the plate-shaped metal support having a recess in the center, when the contact type thermistor of the present invention contacts an object, the temperature is concentrated through the recess having a small area. Heat flow. As a result, the thermal response becomes faster.

(3) The cylindrical metal container and the cylindrical guide are
By mechanically connecting with a compressed spring and providing a small gap between them, when the outer surface of the recess is pressed against the object, the cylindrical metal container moves according to the pressing force, Since it adheres to the surface, the surface temperature can be easily detected even when the object to be measured is different each time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a contact type thin film thermistor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a contact type thin film thermistor according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional surface temperature sensor.

[Explanation of symbols]

 6 plate-shaped metal support 61 recess 7 temperature detector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Ito 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A plate-shaped metal support having a recess in the center,
A contact type thermistor comprising a temperature detector arranged in the recess. 2. A contact type thermistor according to claim 1, wherein a heat sinker is arranged between the recess and the temperature detector. 3. The contact type thermistor according to claim 1, wherein the lead wire of the temperature detector is taken out in a direction perpendicular to the plate-shaped metal support. 4. A cylindrical metal container having a recess at the bottom and a plurality of catches at the lower end, a temperature detector arranged in the recess, and an upper part having a larger diameter than a lower part. A cylindrical guide having an overhang, a spring arranged between the inner surface of the bottom peripheral portion of the cylindrical metal container and the bottom of the overhang of the cylindrical guide, and compressed; A contact type thermistor in which the catching portion of the container is located below the overhanging portion of the cylindrical guide and a small gap is provided between the cylindrical metal container and the cylindrical guide.