JPH0310131A - Thermistor for high temperature use - 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 [Industrial Application Field] The present invention relates to the structure of a high-temperature thermistor made of ceramics.

[Prior Art] Conventionally, as a thermistor for high temperature, the one described in, for example, Japanese Utility Model Application Publication No. 54-49983 is known. This is an air introduction type thermistor, which is made by inserting a PR wire as an electrode into a temperature detection element made of a stabilized zirconia solid electrolyte, press-molding it, and then firing it. It is formed by storing the ceramic insulator tube and inorganic powder in a bottomed protective cylinder.

[Problems to be Solved by the Invention] However, conventional high-temperature thermistors have the following problems.

■ High-temperature thermistors that introduce outside air have a structure that introduces outside air, so the assembly structure is complicated and requires the use of advanced assembly technology and precision parts.
As a result, there is a problem with heat resistance as well as impact resistance.Production is difficult because it requires assembly work of lead wires with air introduction passages and complicated positioning of precision parts. ■ The temperature sensing element may deteriorate due to the influence of outside air or surrounding atmosphere in high temperature conditions.
The resistance-temperature characteristics may change due to lack of oxygen, and there was a problem of lack of heat resistance ■ It is configured to lead outside air to the surface of the temperature detection element through the air introduction passage of the protective tube, filler, and lead wire. Therefore, it took a long time for the ambient temperature to reach the element, and the response was not very good. Normally, the bottomed protective tube is made of SU9310, etc., and the inner wall is treated with an oxide film. The present invention has been made to solve the problems of the conventional technology described above, and an object of the present invention is to overcome these problems and provide a high-temperature thermistor with excellent performance.

[Means for solving the problem] Claim 1 of the present invention made to solve the above problem
A high-temperature thermistor (comprising a temperature detection part consisting of a ceramic temperature detection element and a pair of electrodes connected to the temperature detection element, and a ceramic insulating member that airtightly surrounds the temperature detection part from the outside air), The present invention is a high-temperature thermistor having a gap inside the ceramic insulating member for bringing oxygen gas into contact with the temperature detection element, and the gap is formed in the temperature detection section.

Here, it is preferable to employ a through hole penetrating the temperature detecting section as the gap provided in the temperature detecting section, since the gap can be easily formed and a sufficient volume of the gap can be secured.

Furthermore, as the structure of the temperature detection element and the picture electrode of the temperature detection section, if the picture electrode is laminated by printing so as to sandwich the temperature detection element, manufacturing is simple and the desired resistance-temperature characteristics can be easily obtained. It is suitable because it can be obtained.

Further, it is desirable that the through hole is formed in the temperature detecting portion formed by laminating the layers so as to pass through, for example, the picture electrode or the temperature detecting element in the laminating direction.

The high-temperature thermistor according to claim 2 also includes a temperature detecting element made of a ceramic temperature detecting element, a temperature detecting part comprising a pair of electrodes connected to the temperature detecting element, and a ceramic insulating member that airtightly surrounds the temperature detecting part from the outside air. and 1
: A high-temperature thermistor having a gap inside the ceramic insulating member that allows oxygen gas to come into contact with the temperature detection element, and the output side of the electrode wire extending from the electrode is formed of a dense layer that blocks outside air. The gist is that.

Here, from the viewpoint of high temperature characteristics, it is preferable that the temperature detecting element of Claims 1 and 2 is an ionic conductive, fully stabilized solid electrolyte, for example (f).

Z r O2Y 203, Z r 02-Ca O,
Z r 02-Mgo, The2-La○ (lanthanum genus), etc. can be applied.

Ceramic insulating member (top) A dense insulator having oxidation resistance and high temperature resistance, for example, f/l!203, mullite, spinel, etc. can be used.

[Function] The high temperature thermistor according to claim 1 (a gap is formed in the inner temperature detection part surrounded by the ceramic insulating member, so that oxygen gas in the gap acts as an ionic conductor to the temperature detection element). As a result, the temperature detection element outputs an electrical signal that depends on the outside air temperature via the electrode.In addition, the ceramic insulating member surrounds the temperature detection element and makes it airtight from the outside air, so the temperature detection This prevents the element from deteriorating due to the influence of outside air.Furthermore, the temperature of the surrounding atmosphere is quickly transmitted to the temperature detection element through the ceramic insulating member.The temperature is measured based on the output of this temperature detection element. Because it is done,
Improves responsiveness.

In particular, since the void is formed in the temperature detection section, the void can be easily formed by, for example, making a single hole when forming the temperature detection section. Furthermore, since there is no need to secure a space for a void outside the temperature detection section, further miniaturization is possible, and responsiveness is improved.

In addition, the high temperature thermistor of claim 2 (in addition to the effect of the void described above, the output side of the electrode wire is formed of a dense layer that blocks outside air, so that outside air can enter and oxygen in the void can leak out). As a result, it is possible to prevent the performance of the temperature sensing element from deteriorating due to the influence of the surrounding atmosphere, and improve heat resistance and durability.

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

Fig. 1 is an exploded perspective view of a high-temperature thermistor. Fig. 2 is an enlarged perspective view of its main parts.

As shown in both figures, a temperature sensing element (20 to 50 μm thick) provided on the surface of the inner substrate (0.5 mm thick, 4.5 mm wide, 6.0 mm long) 2. It consists of a kite (width 5, length 5-10 mm) 4 and a pair of electrodes 5, 6 arranged on both sides of the temperature sensing element 4. Also, electrode wires 7, 8 are connected to each electrode 5, 6, respectively. Furthermore, a PR wire 11.12 is connected to the terminal 9.10 on the output side of the electrode wires 7 and 8.Then, a paste portion 13.14 of a thin film for adhesion and an outer substrate are placed on both sides of the above-mentioned members. (Thickness: 0.5 nm, Width: 4.5 mm, Length: 6.0 mm
) 15°16 is placed.

In the temperature detection section 3 (Table Temperature detection element 4. Electrode 5.6
A plurality of cylindrical through holes (φ0
．． 5mm) 17 is formed. Also, electrode wire 7.
8F Inner electrode wires 7a and 8a made of porous material and terminal side electrode wire 7b made of dense layer.

8b. Note that the paste portion 13.
14 (Table) A window portion 18 is provided in the portion corresponding to the temperature detection portion 3 and the terminals 9 and 10.

Since these parts are fired after being laminated,
The high temperature thermistor 1 shown in Fig. 3 is completed.
Next, the composition and manufacturing method of each member will be explained in detail.

First, a green sheet that will become the inner substrate 2 is manufactured. Green sheet (top) Alumina powder with a specific surface area of 6 to 10 points/g, average particle size of 7'l<o, 8 μm, 1 mm S +
It is manufactured by adding 2% by weight of 02.CaO-MgO glass, kneading them with a known PVB binder, and forming them into a sheet using the dokuder blade method.

Next, as shown in Fig. 4, place pt on this green sheet.
By printing the paste, one electrode 6 and the inner electrode wire 8a are integrally formed.

As a pt paste (upper specific surface area 0.6rr?/
g, using PT powder with a density per unit volume of 5 to 6 g/m", containing 16% by weight of Z r O2Y 20 a solid electrolyte as a co-base material, and kneading with a cellulose binder (organic solvent). By doing this, you can use a paste.

Next, on the same green sheet, a denser PT paste is printed overlapping the ends of the inner electrode wires 8a to form terminal side electrode wires 8b that can block air. This pt.
As a paste (above) Pt powder with a specific surface area of 2n (7 g, density per unit volume of 1 g/m3) was used, containing 7 to 8% by weight of Zr02-Y2o3 solid electrolyte as a co-base, and a cellulose binder. Use the paste.

Further IQ: The temperature detection element 4 is laminated on the surface of the electrode 6 by printing. The temperature detection element 4 is Zro2-
A fully stabilized solid electrolyte powder color containing 8 to 15 mol% Y2O3 is used, the average particle size of this powder is 3 μm, and the specific surface area is 2 to 3 μm.
5 rr (/g + 2) is prepared, and this is made into a paste with a cellulose binder.

Next, the above-mentioned electrode 6. In the same manner as the inner electrode wire 8a and the terminal side electrode wire 8b, the other electrode 5° inner electrode wire 7a
and the terminal side electrode wire 7b are printed in an overlapping manner and dried.

Next 1: A plurality of through holes 17, which are spaces where oxygen exists, are formed by piercing the temperature detecting portion 3 and the inner substrate 2 formed by stacking the layers in this manner with a punch.

Furthermore, an adhesive (paste parts 13 and 14) made of alumina paste is printed to cover each of the members except for the temperature detection part 3 and the terminals 9 and 10.

Next, connect the terminals 9.10 of the electrode wires 7 and 8 with a diameter of ψ0°25mm.
Glue the PR wires 11 and 12.

Then, a green sheet that will become the outer substrate 15, 16, similar to the green sheet of the inner substrate 2, is pressure-bonded to the outside of this paste part 13, 14, and after cutting, the resin is removed.

Thereafter, an aging treatment is performed in which the process of firing in an atmosphere of 1520° C. to 1530° C. for 1 hour and further applying a voltage of 1.5 V for 60 seconds in an atmosphere of 680° C. is repeated 5 times.

As a result, the inner substrate 2 and the outer substrates 15 and 16 have a close contact structure after firing, and a high temperature thermistor 1 is manufactured in which the temperature detecting section 3 having the through hole 17 is isolated from the outside air.

Next, the operation of the high temperature thermistor 1 will be explained. PR
External lead wire (FIG. 5) connected to wire M, +2 20.
When a voltage is applied between the external lead wires 20 and 21, the oxygen gas in the through hole 17 acts as an ion conductor via the temperature detection element 4, and the temperature detection element 4 exhibits a resistance value dependent on temperature. (output as two electrical signals).

Based on this electrical signal, the temperature of the external atmosphere can be measured.

To assemble the high temperature thermistor 1, as shown in Table 1 and FIG. ] is welded or brazed and fixed to the tapered metal fitting 23 with a heat-resistant fixing material (cement glass) 24 interposed.

At this time, the tip 1a of the high temperature thermistor 1 is exposed.

With such a configuration, this embodiment provides the following effects.

■ The sealed structure sufficiently isolates it from the outside air, so even in high-temperature conditions of around 1000°C, the temperature detection element 4 does not deteriorate or its resistance-temperature characteristics change due to oxygen deficiency, and its performance is stable. ■ There is no need for a structure that introduces outside air through a protective tube, filler, or lead wire air introduction passage, and the closed structure allows the heat-sensitive part to be exposed, and furthermore, the temperature can be directly applied to the inner substrate 2. Since the detection part 3 is printed, the time it takes for the outside temperature to reach the temperature detection element 4 is shortened, and compared to conventional products,
The responsiveness improves by about 0 to 70%.As a result, for example, an automobile exhaust gas purification catalyst overheats! It can also be used for information and engine control.
Since it is only necessary to make a through hole] 7 in the hole, its formation is extremely easy.

■ The structure of the temperature detection section 3 equipped with this through hole 17 simplifies the structure of the entire high temperature thermistor 1, making it easy to downsize it.L This makes it possible to further improve responsiveness. (2) Since the temperature detection element 4 and the electrodes 5 and 6 sandwiching this element 4 are formed by printing, the electrode pitch can be reduced and the electrode area can be increased. As a result, it became possible to easily obtain suitable resistance-temperature characteristics.■ Since the temperature detection part 3 etc. were formed by this printing, mass production became easy.■ The output extraction side of the electrode wire 7.8 Since it is formed of a dense layer, it is possible to more reliably prevent the intrusion of outside air and the leakage of internal oxygen gas. As a result, the process of sealing the output extraction side with glass, etc. can be omitted.■ The structure is simple because there is no need for a structure to introduce outside air, and there is no need to use advanced assembly technology or precision parts. As a result, impact resistance and heat resistance have been improved.■ Temperature detection element 3 can be assembled exposed without being covered with a metal protection tube, which simplifies the structure and eliminates the need for expensive parts such as a metal protection tube. As it does not need to be used, it is possible to reduce costs.
Manufacture is facilitated without requiring processes such as complicated positioning of precise members.Next, a high temperature thermistor 30 of another embodiment will be explained based on FIG. 6.

The high-temperature thermistor 301 of this embodiment is substantially similar to the high-temperature thermistor 1 of the embodiment described above;
Temperature detection element 32. Electrode 33, 34° Electrode wire 35, 36
．． Paste part 37.38. Outer substrate 39, 40
．． The terminals 41, 42, etc. are provided, but the main difference is that one paste portion 37 and the outer substrate 39 are shorter. That is, the terminals 41 and 42 are exposed and formed, and after firing, lead wires (not shown) are attached to the terminals 41 and 42 by brazing or the like. This configuration simplifies manufacturing and provides the same effects as described above.

It should be noted that the present invention is not limited to the above embodiments,
It goes without saying that the invention can be implemented in various ways without departing from the gist of the invention.

[Effects of the Invention] As explained above, the high-temperature thermistor according to claim 1 of the present invention (i.e., the temperature sensing element is surrounded by the ceramic insulating member airtight from the outside air, so that the high-temperature thermistor of claim 1 of the present invention can be used regardless of the surrounding atmosphere. It exhibits excellent properties such as stable resistance-temperature characteristics. Also, since there is no need for a configuration to introduce outside air, the structure is simple and high responsiveness can be obtained. Furthermore, it l: can be easily formed in the temperature detection part. Also, since there is no need to secure a space for a void outside the temperature detection part, it is possible to make it more compact, which also improves responsiveness. do.

In addition to the above-mentioned effects, the high-temperature thermistor of claim 2 has the output side of the electrode wire formed of a dense layer that blocks outside air, thereby ensuring that outside air does not enter and oxygen leaks out of the void. It is possible to prevent the performance of the temperature detection element from deteriorating due to the surrounding atmosphere.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing a high-temperature thermistor according to an embodiment of the present invention. FIG. 2 is a perspective view showing an enlarged view of the main parts.
Figure 4 is an exploded perspective view showing a high temperature thermistor. Figure 5 is a cross-sectional view showing the high temperature thermistor attached to a metal fitting. Figure 6 is a high temperature thermistor of another embodiment. FIG. Fig. 1 130 - High temperature thermistor 3.31 Temperature detection section 4.32 Temperature detection element 5, 6. 33. 34... Electrode 7, 8. 35. 36... Electrode wires 7a, 8a... Inner electrode wires 7b, 8b... Terminal side electrode wires

Claims (1)

[Scope of Claims] 1. A temperature detecting section consisting of a ceramic temperature detecting element and a pair of electrodes connected to the temperature detecting element, and a ceramic insulating member that airtightly surrounds the temperature detecting section from the outside air. A high temperature thermistor having a gap inside the ceramic insulating member for bringing oxygen gas into contact with the temperature detection element, the gap being formed in the temperature detection part. 2. A humidity detecting section consisting of a ceramic temperature detecting element and a pair of electrodes connected to the humidity detecting element, and a ceramic insulating member that airtightly surrounds the temperature detecting section with respect to the outside air. A high-temperature thermistor having a gap on the inside that allows oxygen gas to come into contact with the temperature detection element, wherein the output side of the electrode wire extending from the electrode is formed of a dense layer that blocks outside air. Thermistor for use.