JP2002188966A - Temperature sensor and its manufacturing method and manufacture control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature sensor having excellent responsiveness, its manufacturing method and a manufacture control method, and especially to provide a high- temperature sensor or the like suitable for use at the high temperature for exhaust gas temperature measuring use of a combustion instrument or an internal combustion engine. SOLUTION: In this temperature sensor equipped with a thermosensitive body and a ceramic body for forming a hollow part enclosing airtightly the thermosensitive body, the ceramic body has irregularities formed on the surface and voids formed inside or the like, and the thermosensitive body is arranged on the thermosensitive face side of a ceramic part forming the hollow part. The hollow part is formed on a position biased to the thermosensitive face side from the center of the temperature sensor. The ceramic body is constituted from a thermosensitive face side ceramic layer equipped with the thermosensitive body, a spacer ceramic layer having an opening part, and a base material ceramic layer working as the base material. The irregularities are formed on the surface of the ceramic body, and through holes or the like are formed together in the ceramic body, to thereby improve furthermore the response of the temperature sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor having excellent responsiveness, a method of manufacturing the same, and a method of managing the same. In particular, the present invention relates to a high-temperature sensor suitable for use at high temperature for measuring exhaust gas temperature of a combustion appliance or an internal combustion engine, a method for manufacturing the same, and a method for managing the manufacturing thereof.

[0002]

2. Description of the Related Art As a temperature sensor, a bulk thermistor element using an oxide sintered body, a Pt resistor, or the like is used. However, there is a problem that the electric characteristics are easily deteriorated due to poisoning by carbon and phosphorus contained in the exhaust gas and fluctuation of the oxygen partial pressure. For this reason, in the bulk type thermistor element, the element is shut off from the outside air by a protective tube such as stainless steel or a glass material to prevent deterioration of electric characteristics. In the case of the Pt resistor, the pattern of the Pt resistor provided on the insulating substrate is sealed with a glass material to prevent deterioration of electric characteristics.

[0003] In the case of automotive applications where vibrations are severe, the bulk type thermistor element is fixed to a substantially central portion of the protective tube by a filler such as cement or by caulking. This is to prevent the thermistor element from coming into contact with the protective tube and being damaged by intense vibration.

In order to quickly control the combustion of a combustion appliance or an internal combustion engine, it is necessary to improve the responsiveness of the heat-sensitive element. As a method of improving the responsiveness of the heat-sensitive element, a method of reducing the unnecessary heat capacity by reducing the thickness of the protective tube (JP-A-9-189618), or a method of increasing the thermal conductivity from the outside air. A method of flattening the element shape (Japanese Patent Application Laid-Open No. 9-218110) is known.

[0005]

SUMMARY OF THE INVENTION In the conventional method,
Since the thermistor element is protected by a stainless steel layer, a glass layer, a cement layer, or the like having relatively low thermal conductivity, there is a problem that a loss time occurs before heat of exhaust gas or the like reaches the thermistor element. Further, since an air layer exists between these layers and the element, thermal conductivity may be deteriorated. Further, there occurs a heat drawing phenomenon in which the heat transmitted to the thermistor element escapes to reduce the responsiveness. For this reason, it is not easy to further improve the responsiveness of the thermistor with the conventional structure. On the other hand, although the Pt resistor provided on the insulating substrate has excellent responsiveness, the heat resistance of the glass seal is only up to about 600 ° C., and is used for measuring the exhaust gas temperature of an internal combustion engine that can reach 1000 ° C. Has a narrow application temperature range.

It is also conceivable to reduce the heat capacity of the heat-sensitive element itself, such as a thermistor element, to reduce the heat capacity of the heat-sensitive element itself, thereby improving the response. However, in order to obtain desired characteristics, it is necessary to accurately assemble the electrodes with the heat-sensitive element, which causes problems such as a decrease in mass productivity and an increase in cost. Therefore, there is naturally a limit in reducing the size of the heat-sensitive body itself.

According to the present invention, the heat-sensitive body is hermetically surrounded by a ceramic base, and the flow of heat to the sensor is increased in the ceramic body, and irregularities, voids, and the like for suppressing heat extraction to the rear end side of the sensor are provided. An object of the present invention is to provide a temperature sensor having improved responsiveness by providing the temperature sensor. It is another object of the present invention to provide a method of manufacturing the temperature sensor and a method of managing the temperature. In particular, it is an object of the present invention to provide a high-temperature sensor suitable for use at high temperatures for measuring the exhaust gas temperature of a combustion appliance or an internal combustion engine, a method of manufacturing the same, and a method of managing the manufacturing thereof.

[0008]

The temperature sensor according to the present invention comprises:
A heat-sensitive body and a ceramic body having a hollow portion surrounding the heat-sensitive body in an airtight manner, wherein a plurality of irregularities (see FIG. 10) are formed on the surface of the ceramic body. By forming irregularities on the surface of the ceramic body, the surface area of the sensor can be increased, and the amount of heat flowing into the thermosensitive body can be increased.

In addition, in the present invention, in addition to forming irregularities on the surface of the ceramic body, a plurality of voids (see FIG. 11) are formed inside the ceramic body to suppress heat transfer to the rear end side of the sensor. be able to. Further, by forming a plurality of through holes (see FIGS. 13 and 15) in the ceramic body, an increase in the amount of heat inflow due to an increase in the surface area of the sensor and a suppression of heat drawing to the rear end side of the sensor by the through holes are suppressed. It is possible. Usually, this through hole is formed in the thickness direction of the ceramic body,
The cross-sectional shape can be circular or polygonal depending on the space of the ceramic body. Also, the surface of the ceramic body may be provided with irregularities, and the ceramic body may be provided with a plurality of voids (see FIG. 12) or through holes (see FIG. 14). As a result, the amount of heat flowing into the heat sensitive body can be further increased, and the heat removal to the rear end side can be suppressed more efficiently.

As described above, by forming irregularities, voids, and the like on the surface and inside of the ceramic body, the flow of heat into the heat-sensitive portion is increased, and the heat extraction from the heat-sensitive portion to the rear end of the sensor is suppressed. The responsiveness of the sensor can be improved.

The irregularities on the surface of the ceramic body are as follows:
Formed by pressing a mold having irregularities on the surface of the unfired body that becomes a ceramic body by firing, and (B) performing sandblasting, ultrasonic processing, or laser processing on the surface of the fired ceramic body. it can.

As a method of forming a plurality of through holes in the ceramic body, a method of punching out a laminated unfired ceramic body by using a mold, or a method of processing the fired laminated ceramic body with a drill, a laser, or the like is used. Is mentioned. As a method of forming a plurality of voids inside the ceramic body, there is a method of punching an unfired ceramic sheet to be a spacer ceramic layer using a mold.

Further, the temperature sensor of the present invention has a hermetically sealed structure in which a heat sensitive body is hermetically enclosed in a hollow portion formed of a dense ceramic body. For this reason, poisoning by carbon, phosphorus, and the like contained in exhaust gas and the like can be suppressed. Further, ceramics have high corrosion resistance and are hardly corroded by exhaust gas or the like, so that airtightness can be maintained for a long period of time. Further, by using a ceramic having excellent heat resistance, a temperature sensor that can withstand a high temperature of about 1000 ° C. can be obtained.

The ceramic body is not particularly limited as long as it is a dense body capable of ensuring airtightness, but one having characteristics such as oxidation resistance, high temperature resistance, and high thermal conductivity is used according to the use of the sensor. Selected. Ceramics used for forming this ceramic body include alumina, mullite, spinel,
Aluminum nitride, silicon nitride, or the like can be used. An oxide ceramic can be fired simultaneously with an oxide thermistor or a Pt resistor, and a nitride ceramic can be fired simultaneously with a carbide thermistor. In any case, since the ceramic body and the heat sensitive body can be formed by simultaneous firing, the manufacturing cost can be reduced.

As a method of forming a hermetically sealed structure in a hollow portion in which a heat sensitive body is formed of a dense ceramic body, a known ceramic multilayer lamination technique is preferably used. A co-firing method using a ceramic green sheet and a thick-film printing multilayer method are preferably used. If the reliability and the thermal conductivity are not affected, a method in which a plurality of ceramic members are glass-joined to form a hollow portion can also be used.

The materials of the heat-sensitive body include NTC thermistor, P
TC thermistors, metal resistors, and the like. NTC
As the thermistor, oxide YCrO_ThreeKeirobus
Kite, MgO-Al_TwoO_ThreeSpinel, Cr_TwoO_Three-Al
_TwoO_ThreeSystem corundum, Y_TwoO_Three-ZrO_TwoSystem flourite
Other conductive materials such as SiC are used as carbides.
Can be. As PTC thermistors, oxide
BaTiO3_Three, V_TwoO _Five−Cr_TwoO_ThreeUse materials such as
be able to. Pt, Au, A
g, at least one selected from Pd, Ir and Rh
Can be used, considering the usage conditions, the pattern of the resistor
The resistance value can be controlled by changing. Use under high temperature
In consideration of the use, it is preferable to use a Pt-based material. this
Among them, PTC thermistors have a sharp temperature range.
Since it has a resistance value change, it
Accuracy is reduced. On the other hand, metal resistors have high temperature detection accuracy.
However, the load on the detection circuit side due to the small resistance output value
Becomes larger. For these reasons, from 300 ° C to 10 ° C
Easy temperature detection over a wide temperature range around 00 ° C
In this case, an NTC thermistor is most preferable.

In order to save space by downsizing the sensor, the heat sensitive body may be a thick film type or a thin film type. The thick film type can be easily printed by a known screen printing method, and can be formed by co-firing with ceramic or by baking on a fired substrate. The thin film can be formed on a fired substrate by a gas phase method such as a sputtering method or a CVD method, or a liquid phase method such as a dip coating method.

As a material of the electrodes and lead wires to be combined, it is preferable to use a noble metal. This is because the noble metal has poor reactivity with oxides, carbides, and the like, and thus does not lower the conductive characteristics. Further, even when the heat sensitive body is a metal resistor, it can be used for a metal resistor by selecting an electrode area and a lead wire width so as to have a lower resistance than the heat sensitive body. For example, at least one selected from Pt, Au, Ag, Pd, Ir, and Rh can be used for an electrode or a lead wire. Considering use at high temperatures, it is preferable to use a Pt-based material.

In the temperature sensor of the present invention, it is preferable that a heat sensitive body is formed on the heat sensitive surface side of the ceramic body forming the hollow portion. The term "thermosensitive surface side" as used herein refers to a side on which the ceramic body is exposed to exhaust gas from a combustion appliance, an internal combustion engine, or the like. Only a heat-sensitive surface-side ceramic layer having a dense and relatively high thermal conductivity is interposed between the exhaust gas and the heat-sensitive body. Unlike conventional bulk thermistors, low heat conductivity materials such as stainless steel, cement, and air are not interposed between the exhaust gas and the heat-sensitive material, so heat from the exhaust gas and the like is efficiently transmitted to the heat-sensitive material. be able to.

On the other side of the heat-sensitive surface, the vicinity of the heat-sensitive body is insulated by the sealed air, so that the heat transferred to the heat-sensitive body escapes and the heat-reducing phenomenon that lowers the responsiveness does not easily occur. . Therefore, the responsiveness of the temperature sensor can be improved.

In the temperature sensor according to the present invention, the hollow portion is preferably formed at a position deviated from the center of the temperature sensor toward the heat-sensitive surface. Here, the “center of the temperature sensor” refers to the center in the vertical direction, that is, the thickness direction, when the surface on which the heat sensitive body is formed is in the horizontal direction. By forming the hollow portion at a position biased toward the heat-sensitive surface-side ceramic layer, the heat-sensitive surface-side ceramic layer can be made relatively thin, and heat from exhaust gas or the like can be quickly transmitted to the heat-sensitive body. The base ceramic layer can be made relatively thick to have mechanical strength. Therefore, the responsiveness can be controlled by changing the thickness of the heat-sensitive surface-side ceramic layer while securing the mechanical strength of the temperature sensor itself.

The heat capacity of the temperature sensor of the present invention is adjusted by increasing or decreasing the thickness of the ceramic layer on the heat-sensitive surface, particularly when the number, size, position, etc. of the unevenness, voids, and through-holes to be formed are substantially the same. By doing so, the temperature sensor can be adjusted to a desired response. For example, in the case where the response characteristics of the heat-sensitive element fluctuate depending on the production lot, a preliminary test for the response is performed in advance, and the thickness of the ceramic layer on the heat-sensitive surface is increased or decreased based on the result, and the response is improved. Can be combined. By using such a manufacturing management method, even when the response characteristics of the heat sensitive body vary depending on the manufacturing lot, the manufacturing yield of the temperature sensor does not decrease.

The temperature sensor of the present invention may be formed by using a known ceramic multilayer technology. A multilayered ceramic green sheet or a printed multilayer insulating paste may be used. For example, when the configuration is as shown in the exploded perspective view shown in FIG. 1, the manufacture is easy. A ceramic body forming a hollow portion that hermetically surrounds the heat-sensitive body (4); a heat-sensitive surface-side ceramic layer (1) including the heat-sensitive body (4); a spacer ceramic layer (3) having an opening (31); This is because the base ceramic layer (2) serving as the base can be easily formed using ceramic green sheets or green paste.

Electrodes (5a, 5b) for extracting electric signals are formed on the thermosensitive body (4). The structure of the heat sensitive body and the electrode is preferably a sandwich structure as shown in FIG. This is because the amount of alkali metal or alkaline earth metal diffused from the green sheet for the heat-sensitive surface-side ceramic layer to the heat-sensitive material, which is generated at the time of firing, can be reduced. In addition, the electric signal from the thermosensitive body is taken out from the lead wires (6a, 6b) connected to the ends (51a, 51b) of the electrodes.

When the heat-sensitive element has resistance to an alkali metal or an alkaline earth metal, a structure in which the heat-sensitive element straddles the parallel electrodes as shown in FIG. 8 is also possible. This method has an advantage that the number of steps can be reduced since the formation of the electrodes (5a, 5b) is completed by one screen printing.

FIG. 9 shows the thickness t _{1 of the} ceramic layer on the heat-sensitive surface side.
And the relationship between the thickness t ₂ of the spacer ceramic layer thickness t ₃ and the substrate ceramic layer is a depiction with reference to the sectional view of the thermistor. In the temperature sensor of the present invention, the preferable thickness of each ceramic layer can be appropriately set depending on the number of irregularities, voids, and number of through holes, the size, and the like. May be made as follows.

The thickness t ₁ of the heat sensitive surface side ceramic layer is 0.1
A range of about 1.0 mm is good. If the thickness is less than 0.1 mm, cracks due to thermal shock and deformation during the manufacturing process are likely to occur, and if it exceeds 1.0 mm, the responsiveness decreases. In consideration of responsiveness, mechanical strength, and the problem of deformation, the range is preferably 0.1 to 0.9 mm.

Further, the thickness t of the spacer ceramic layer
₃ and the total thickness t ₂ of the base ceramic layer (t ₂ + t ₃₎ it is may be in the range of 0.3 to 3.0 mm. If the thickness is less than 0.3 mm, the strength required as a temperature sensor cannot be secured, and the temperature sensor is liable to be damaged by impact such as vibration. If the thickness exceeds 3.0 mm, air remains between the layers at the time of lamination and bubbles remain, This is because cracks are likely to be generated around the frame when punching the portion (31) or the opening for forming the gap. In order to improve the reliability, it is preferably 0.3 to 1.
The range is preferably 5 mm, more preferably 0.5 to 1.2 mm.

Further, the thickness t _{3 of the} spacer ceramic layer
T ₁ / (t ₂ + t ₃ ), which is the ratio of the thickness t ₁ of the heat-sensitive surface-side ceramic layer to the total thickness t ₂ of the base ceramic layer, is preferably less than 1. The thickness t _{1 of the} ceramic layer on the heat-sensitive surface side
This is because the heat capacity on the heat-sensitive surface side can be reduced by setting the thickness of the temperature sensor relatively thin, so that the responsiveness of the temperature sensor can be improved. Preferably, the range is 0.1 to 0.9.

[0030]

Embodiments of the present invention will be described with reference to the drawings. Example 1 A YCrO ₃ -based thermistor material was used as a heat-sensitive body, and Al ₂ O ₃ was used as a ceramic body. FIG. 1 is an exploded perspective view of a thick-film thermistor. FIG. 2 is a view of the thermistor as viewed from directly above. FIG. 3 to FIG. 6 are explanatory views of the process, and are shown by the cross section taken along a dashed line (a) in FIG. The external dimensions of the thermistor (excluding the lead wire) are 60 mm long.
The width is 5 mm. In addition, actually, the irregularities,
Although gaps and the like are formed, in the drawings showing this step and the like, illustration thereof is omitted for clarity.

[0031] Preparation of paste for thermistor element Y ₂ O ₃ , SrCO ₃ , Cr ₂ O ₃ , Al ₂
O ₃ , Fe ₂ O ₃ and ZrO ₂ (each having a purity of 99.9% or more) are prepared. These are weighed so as to have a ratio of mass% in terms of oxide as shown in Table 1, placed in a resin pot together with a cobblestone made of silicon nitride and a solvent (ethanol), and wet-mixed. (However, SiO ₂ is blended in a later step.) After the solvent is dried and removed, it is calcined and pulverized in an air atmosphere at 1300 ° C. for 5 hours, and calcined with an average particle size of 1 to 2 μm. Powder.

The calcined powder obtained had an average particle size of 0.2 μm
The SiO ₂ powder is added, the ratio of each component is formulated to be a composition ratio shown in Table 1. This compounded powder is put into a resin pot together with a silicon nitride boulder and a solvent (ethanol) and wet-mixed. The obtained slurry is dried under the conditions of 80 ° C. × 3 hours, and further passed through a 250-mesh sieve to obtain a granulated powder.

The binder (ethyl cellulose) is added to the granulated powder.
And a solvent (butyl carbitol), and a paste for a thermistor element is obtained using an Ishikawa-type kneader.

[0034]

[Table 1]

[0035] Fabrication of thermistor Heat sensitive surface side ceramic layer (1), spacer ceramic layer
(3) and ceramic ceramics to be the base ceramic layer (2)
Make a lean sheet. Specific surface area is 9.4m ^Two/ G,
Alumina powder with an average particle size of 0.4 μm_Two-Ca
O-MgO-based glass is added by 0.5% by mass. these
Knead using an acrylic binder, and doctor blade
The sheet is formed by the method. Ceramic green sheet thickness
After firing, t₁: 0.9 mm, t_Two: 0.8 mm,
t_Three: 0.37 mm.

Next, each of the ceramic green sheets of the heat-sensitive surface side ceramic layer (1) and the base ceramic layer (2) obtained above is subjected to the following steps: A metal mold having irregularities is pressed against the surface of each sheet to form circular irregularities (diameter: 0.8 mm, depth: 0.1 m)
m, 16) are formed.

Next, as shown in FIG. 3, an opening (31) and cutouts (32a, 32b) for lead wires are punched out using a die on a ceramic green sheet to be a base ceramic layer (2). The formed ceramic green sheet serving as the spacer ceramic layer (3) is pressed to form a green body (101) serving as the base ceramic layer and the spacer ceramic layer.

Next, Pt to be an electrode (5a) is formed on a ceramic green sheet to be a heat-sensitive surface side ceramic layer (1).
The paste is printed and formed in a predetermined pattern. Pt paste, the average particle size in the Pt powder 0.6μm having the same composition as the thermistor element Y ₂ O ₃ -Cr ₂ O ₃ system 3 wt% of conductive material
It is added and kneaded with a cellulose binder.

After the paste for the thermistor element prepared on the electrode (5a) is applied by printing and dried, a Pt paste serving as the electrode (5b) is further formed on the paste in a predetermined pattern. Then, the ends of the electrodes (51a,
A lead wire made of platinum having a diameter of 0.3 mm is bonded to 51b) to form a green body (102) serving as a thermistor element and a ceramic layer on the heat-sensitive surface side (see FIG. 4).

Then, as shown in FIGS. 5 and 6, a green body (101) serving as a base ceramic layer and a spacer ceramic layer, a heat-sensitive surface side ceramic layer and a green body (102) serving as a thermistor element are pressed. Thus, a green body (100) to be a thermistor is formed.

After firing, the green body serving as the thermistor was cut to have a length of 60 mm and a width of 5 mm, and then the binder was removed in the air at 250 ° C. for 6 hours.
Obtain a defatted body. The degreased body is fired in the atmosphere at 1480 ° C. for 2 hours to obtain a thermistor having irregularities (7) formed on the surface of the ceramic body (see FIG. 10).

Evaluation of the responsiveness of the thermistor The responsiveness of the thermistor obtained above was evaluated as follows. An opening is provided in a metal pipe having a diameter of 30 mm, and a thermistor is inserted vertically into the opening. Hot air at 600 ° C. is flowed through the metal pipe at a flow rate of 6 m / s, and 63% responsiveness is measured. "63% here"
“Responsivity” refers to the time required for the temperature detected by the thermistor to rise from room temperature to 378 ° C. Table 2 shows the results.

Example 2 An opening (31) and a lead wire notch (32a, 32b) are formed in a green sheet to be a spacer ceramic layer (3) before pressure bonding without forming irregularities on the surface of the ceramic body. At the time, after firing, the thermistor was the same as in Example 1 except that openings (length: 2.5 mm, width: 1.8 mm, two pieces) serving as voids inside the ceramic body were formed using a mold. Is obtained to obtain a thermistor having a void (8) formed inside the ceramic body (see FIG. 11). Furthermore, the same responsiveness evaluation as in Example 1 was performed using this thermistor, and the results are shown in Table 2.

Example 3 A thermistor was manufactured in the same manner as in Example 1 except that voids were formed inside the ceramic body in the same manner as in Example 2, and irregularities (7) were formed on the surface of the ceramic body. A thermistor having a void (8) formed inside the body is obtained (see FIG. 12). Furthermore, the same responsiveness evaluation as in Example 1 was performed using this thermistor, and the results are shown in Table 2.

Example 4 A green body (1) was formed without forming irregularities on the surface of the ceramic body.
After the formation of (00), a thermistor was manufactured in the same manner as in Example 1 except that a cylindrical perforated portion (diameter: 1 mm, 8 pieces) that became a through hole after firing was formed by punching with a mold.
A thermistor having a through-hole (9a) formed in a ceramic body is obtained (see FIG. 13). Furthermore, the same responsiveness evaluation as in Example 1 was performed using this thermistor, and the results are shown in Table 2.

Example 5 A square through hole (length: 3 mm, width: 0.8) was formed in a ceramic body.
mm, 3 pieces) were formed in the same manner as in Example 1 except that the thermistor was formed in the same manner as in Example 4. As a result, irregularities (7) were formed on the surface of the ceramic body, and through holes (9b) were formed in the ceramic body. Is obtained (see FIG. 14). Furthermore, the same responsiveness evaluation as in Example 1 was performed using this thermistor, and the results are shown in Table 2.

Comparative Example 1 A conventional bulk thermistor was used. This is 2
mm, 1.5mm high bulk thermistor with 4mm diameter
It is put in a stainless steel metal tube and fixed with cement. Furthermore, the same responsiveness evaluation as in Example 1 was performed using this thermistor, and the results are shown in Table 2.

[0048]

[Table 2]

According to Table 2, the response time of a conventional temperature sensor using a bulk thermistor (Comparative Example 1) was 11 seconds, whereas the response time of a ceramic body having irregularities (Example 1) was 11 seconds. 9.5 seconds for the ceramic body having a plurality of voids inside the ceramic body (Example 2), 8.5 seconds for the body having both of them (Example 3), 8.5 seconds. The temperature sensor according to Examples 1 to 5 of the present invention has a response time of 7.4 seconds, and the temperature sensor of Examples 1 to 5 of the present invention has a response time of 7.4 seconds. It was found to be short and responsive.

In the thermistor according to one embodiment of the present invention, at least one of irregularities, voids, and through holes is formed on the surface or inside of the ceramic body, and the thermistor element itself is sealed to insulate the air. Therefore, the responsiveness is better than Comparative Example 1 using a bulk thermistor in which a low heat conductive material such as stainless steel or cement is interposed in the heat conduction path. There is also an advantage that the influence of heat removal and poisoning is extremely small.

The present invention is not limited to the specific embodiments described above, but may be variously modified within the scope of the present invention in accordance with the purpose and application. For example, the cylindrical through hole (9a) of the fourth embodiment can be a rectangular through hole (9b) as shown in FIG. It becomes an excellent temperature sensor.

[0052]

According to the present invention, excellent responsiveness and
A temperature sensor that can be mass-produced at low cost can be provided.
Further, the temperature sensor of the present invention has a structure in which at least one of irregularities, voids, and through holes is formed on the surface or inside of the ceramic body, and the heat-sensitive body is hermetically sealed in a hollow portion formed of the dense ceramic body. Because of the enclosed structure, poisoning by carbon, phosphorus and the like contained in exhaust gas and the like can be suppressed. Furthermore, since ceramic has high corrosion resistance and is hardly corroded by exhaust gas or the like, it can maintain airtightness for a long period of time and has excellent heat resistance, so that it is a temperature sensor that can withstand high temperatures of about 1000 ° C. be able to.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a thick-film thermistor according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a thick-film thermistor according to one embodiment of the present invention, as viewed from directly above.

FIG. 3 is an explanatory diagram illustrating an example of a method for manufacturing a thick-film thermistor according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating an example of a method for manufacturing a thick-film thermistor according to one embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating an example of a method for manufacturing a thick-film thermistor according to one embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating an example of a method for manufacturing a thick-film thermistor according to one embodiment of the present invention.

FIG. 7 is an explanatory diagram in the case where the configuration of the thermistor element and the electrode is a sandwich structure.

FIG. 8 is an explanatory diagram in the case where the thermistor element straddles a parallel electrode.

9 is a cross-sectional view of a thermistor that shows a relationship between the thickness t ₃ of the thickness t ₂ and the substrate ceramic layer having a thickness t ₁ of the heat-sensitive surface side ceramic layer and the spacer ceramic layer.

FIG. 10 is an explanatory diagram in the case where irregularities are formed on the surface of a ceramic body.

FIG. 11 is an explanatory diagram when a gap is formed inside a ceramic body.

FIG. 12 is a diagram illustrating a case where irregularities are formed on the surface of a ceramic body and voids are formed inside;

FIG. 13 is an explanatory diagram in a case where a round through hole is formed in a ceramic body.

FIG. 14 is an explanatory diagram in the case where irregularities are formed on the surface of a ceramic body and through holes are formed.

FIG. 15 is an explanatory diagram of a case where a rectangular through hole is formed in a ceramic body.

[Explanation of symbols]

1; heat sensitive surface side ceramic layer, 2; base ceramic layer,
3; spacer ceramic layer, 31; opening, 32a,
32b; cutout of lead wire, 4; thermistor element, 5
a, 5b; electrode, 51a, 51b; end of electrode, 6a,
6b; lead wire, 7; unevenness, 8; void, 9a; round through hole, 9b; square through hole.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoshi Iio 14-18 Takatsuji-cho, Mizuho-ku, Nagoya F-term in Japan Special Ceramics Co., Ltd. 2F056 QF01 QF08 5E034 BA09 BB05 DA02 DB03 DE14 DE19 DE20

Claims (11)

[Claims] 1. A temperature sensor comprising: a heat sensitive body; and a ceramic body having a hollow portion hermetically surrounding the heat sensitive body, wherein a plurality of irregularities are formed on a surface of the ceramic body. 2. A temperature sensor, comprising: a heat sensitive body; and a ceramic body having a hollow portion hermetically surrounding the heat sensitive body, wherein a plurality of voids are formed inside the ceramic body. 3. A ceramic body comprising: a heat sensitive body; and a ceramic body having a hollow portion hermetically surrounding the heat sensitive body, wherein a plurality of irregularities are formed on a surface of the ceramic body, and a plurality of voids are formed inside the ceramic body. A temperature sensor, wherein a temperature sensor is formed. 4. A temperature sensor, comprising: a heat-sensitive body; and a ceramic body having a hollow portion hermetically surrounding the heat-sensitive body, wherein a plurality of through holes are formed in the ceramic body. 5. A thermo-sensitive body, comprising: a ceramic body having a hollow portion which hermetically surrounds the thermo-sensitive body, wherein a plurality of irregularities are formed on a surface of the ceramic body, and a plurality of through holes are formed in the ceramic body. A temperature sensor characterized by being formed. 6. The temperature sensor according to claim 1, wherein said heat-sensitive body is disposed on a heat-sensitive surface side of said ceramic body. 7. The method according to claim 1, wherein the hollow portion is formed so as to be biased toward the heat-sensitive surface in the thickness direction of the ceramic body.
A temperature sensor according to any one of claims 6 to 7. 8. The ceramic body according to claim 1, wherein the ceramic body comprises a heat-sensitive surface-side ceramic layer having a heat-sensitive body, a spacer ceramic layer having an opening, and a base ceramic layer. A temperature sensor as described. 9. The heat-sensitive-surface-side ceramic layer has a thickness of 0.1 mm.
9. The temperature sensor according to claim 8, which is 1 to 1.0 mm. 10. A method for manufacturing a temperature sensor comprising a heat sensitive body and a ceramic body having a hollow portion hermetically surrounding the heat sensitive body, wherein (A) the surface of the unfired body that becomes the ceramic body by firing Pressing a mold having irregularities on the ceramic body, and (B) forming irregularities on the surface of the ceramic body by any of sandblasting, ultrasonic processing, or laser processing on the surface of the fired ceramic body. A method for manufacturing a temperature sensor. 11. The method for controlling the production of a temperature sensor according to claim 1, wherein a change in responsiveness due to a production lot of the heat-sensitive element is checked in advance by conducting a preliminary test, and the result is determined. Adjusting the thickness of the ceramic body on the heat-sensitive surface side based on the above method.