WO2014104293A1 - Heater - Google Patents

Heater Download PDF

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Publication number
WO2014104293A1
WO2014104293A1 PCT/JP2013/085105 JP2013085105W WO2014104293A1 WO 2014104293 A1 WO2014104293 A1 WO 2014104293A1 JP 2013085105 W JP2013085105 W JP 2013085105W WO 2014104293 A1 WO2014104293 A1 WO 2014104293A1
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WO
WIPO (PCT)
Prior art keywords
ceramic structure
heater
heating resistor
groove
folded portion
Prior art date
Application number
PCT/JP2013/085105
Other languages
French (fr)
Japanese (ja)
Inventor
朝 島袋
Original Assignee
京セラ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 京セラ株式会社 filed Critical 京セラ株式会社
Priority to JP2014554592A priority Critical patent/JP5960845B2/en
Priority to EP13869090.4A priority patent/EP2941090B1/en
Publication of WO2014104293A1 publication Critical patent/WO2014104293A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/40—Heating elements having the shape of rods or tubes
    • H05B3/42—Heating elements having the shape of rods or tubes non-flexible
    • H05B3/48—Heating elements having the shape of rods or tubes non-flexible heating conductor embedded in insulating material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23Q—IGNITION; EXTINGUISHING-DEVICES
    • F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
    • F23Q7/001—Glowing plugs for internal-combustion engines
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/141—Conductive ceramics, e.g. metal oxides, metal carbides, barium titanate, ferrites, zirconia, vitrous compounds
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/027—Heaters specially adapted for glow plug igniters

Definitions

  • the present invention relates to a heater used in a hair iron, a water heater, an oxygen sensor, an air-fuel ratio sensor, a glow plug, various combustion devices, a semiconductor manufacturing apparatus, or the like.
  • Examples of heaters used for hair irons include ceramic heaters described in Japanese Patent Application Laid-Open No. 2006-40882 (hereinafter referred to as Patent Document 1).
  • the ceramic heater described in Patent Document 1 includes a ceramic base, a heat generating part provided in the ceramic base, and a lead part provided in the ceramic base and connected to the heat generating part.
  • the heat generating portion (heat generating resistor) has two lined linear portions and a folded portion connecting these linear portions.
  • a portion located between the two linear portions arranged in the ceramic base body (ceramic structure) and in the vicinity of the turned-up portion tends to have a particularly high temperature.
  • the surface of the ceramic structure has the highest temperature in the region facing the above-described portion (hereinafter referred to as the highest heat generating portion), and the temperature decreases as the distance from the highest heat generating portion increases with the highest heat generating portion as the center.
  • the temperature distribution was correct. As described above, when a biased temperature distribution occurs on the surface of the ceramic structure, cracks may occur on the surface of the ceramic structure by repeatedly using the heater. As a result, it has been difficult to improve the long-term reliability of the heater.
  • the heater according to one aspect of the present invention includes a ceramic structure and a heating resistor having a folded portion embedded in the ceramic structure, and the ceramic structure has a surface facing the folded portion. A groove portion surrounding the folded portion;
  • a heater according to another aspect of the present invention includes a ceramic structure and a heating resistor having a folded portion embedded in the ceramic structure, and the ceramic structure has a surface facing the folded portion. Among these, it has a recessed part in the area
  • FIG. 7 is a partially enlarged view (a) showing a heater according to a modification of the present invention and a sectional view (b) taken along the C-C ′ section. It is sectional drawing which shows the heater of the modification of this invention. It is sectional drawing which shows the heater of the modification of this invention.
  • FIG. 1 is a perspective view showing a heater 100 according to an embodiment of the present invention.
  • 2A is a partially enlarged view in which the region A of the heater 100 shown in FIG. 1 is enlarged
  • FIG. 2B is a cross-sectional view taken along the line B-B ′.
  • a heater 100 according to an embodiment of the present invention includes a ceramic structure 1, a heating resistor 2, a power supply line 3, and a lead terminal 7.
  • the heating resistor 2 and the power supply line 3 are indicated by broken lines through the ceramic structure 1.
  • the heater 100 is used in, for example, a hair iron, a water heating heater, an oxygen sensor, an air-fuel ratio sensor, a glow plug, or a semiconductor manufacturing apparatus.
  • the ceramic structure 1 is a member for holding the heating resistor 2 and the feeder 3 inside. By providing the heating resistor 2 and the power supply line 3 inside the ceramic structure 1, the environmental resistance of the heating resistor 2 and the power supply line 3 can be improved.
  • the ceramic structure 1 is a rod-shaped member.
  • the ceramic structure 1 is made of a ceramic material such as alumina, silicon nitride, aluminum nitride, or silicon carbide. If the ceramic structure 1 is, for example, a square bar shape, in this case, for example, the length of the short side of the outer periphery is 25 mm, the length of the long side is 25 mm, and the length in the longitudinal direction is 50 mm. .
  • the heating resistor 2 is a member that generates heat when energized.
  • the heating resistor 2 is embedded in the ceramic structure 1.
  • the heating resistor 2 is disposed so as to face a surface (hereinafter, referred to as a main surface) including a long side of the outer periphery of the ceramic structure 1 and a side in the longitudinal direction.
  • the heating resistor 2 has two linear portions 22 that are arranged side by side, and a folded portion 21 that connects these linear portions 22 and has a semicircular shape on the outer periphery and inner periphery.
  • the heating resistor 2 is indicated by a broken line through the ceramic structure 1.
  • the folded portion 21 is provided near the front end of the ceramic structure 1, and the linear portion 22 is provided from the end portion of the folded portion 21 toward the rear end side.
  • the heating resistor 2 is made of a conductive ceramic material such as tungsten carbide.
  • the heating resistor 2 has, for example, a line width of 0.2 to 1.5 mm and a thickness of 0.3 to 3 mm.
  • the radius of curvature of the folded portion 21 is, for example, 0.15 to 1 mm on the inner periphery and 0.5 to 2 mm on the outer periphery.
  • the heat generated by the heating resistor 2 is conducted inside the ceramic structure 1 and is emitted from the surface of the ceramic structure 1 to the outside.
  • the feeder 3 is a pair of wiring members for electrically connecting the heating resistor 2 together with the lead terminal 7 to a power source (not shown) outside the ceramic structure 1.
  • Most of the feeder 3 is embedded in the ceramic structure 1 and one end is electrically connected to the heating resistor 2. That is, one end of each feeder 3 is connected to a separate end of the heating resistor 2.
  • the other end of each power supply line 3 is drawn out to the surface on the rear end side of the ceramic structure 1 to be connected to an external power source, and separate lead terminals 7 are connected thereto.
  • the power supply line 3 is formed in a linear shape as a wiring that runs around the inside of the ceramic structure 1.
  • the feeder 3 is made of a conductive ceramic material such as tungsten carbide, and is formed as a wiring having a resistance lower than that of the heating resistor 2.
  • the line width of the feeder line 3 is, for example, 0.2 to 2 mm, and the thickness is, for example, 0.3 to 4 ⁇ m.
  • the lead terminal 7 is a rod-shaped conductive member for electrically connecting the feeder 3 to an external power source.
  • the lead terminal 7 is joined to each power supply line 3 drawn out on the surface of the ceramic structure 1 opposite to the side where the heating resistor 2 is provided.
  • the lead terminal 7 is made of nickel, for example.
  • a brazing material is used for joining the lead terminal 7 and the feeder 3.
  • the brazing material for example, silver brazing is used.
  • the dimensions of the lead terminal 7 are, for example, a width of 0.2 to 2 mm, a thickness of 0.2 to 2 mm, and a length of 10 mm or more.
  • the heating resistor 2 has two linear portions 22 that are arranged side by side and a folded portion 21 that connects these linear portions 22.
  • a portion located between the two linear portions 22 arranged in the ceramic structure 1 and in the vicinity of the turned-up portion 21 is particularly high in temperature. Therefore, as for the surface of the ceramic structure 1, the area
  • the highest heat generating portion 10 is indicated by a two-dot chain line.
  • the ceramic structure 1 has the groove portion 4 surrounding the folded portion 21 of the heating resistor 2 on the surface of the region on the tip side of the highest heating portion 10.
  • the groove part 4 is provided in the shape of a square frame so as to surround the folded part 21.
  • the surface (bottom surface of the groove part 4) of the part in which the groove part 4 is provided can be brought closer to the heating resistor 2 than the surrounding surface.
  • the temperature of the surface of the part in which the groove part 4 is provided becomes easy to rise.
  • the temperature difference between the maximum heat generating part 10 and the vicinity thereof can be reduced.
  • the uneven temperature distribution on the surface of the heater 100 can be reduced.
  • the long-term reliability of the heater 100 can be improved.
  • such a dimension of the groove portion 4 is, for example, a square shape having a width of 0.15 mm, a depth of 0.1 mm, and an outer peripheral side of 2 mm. It is formed.
  • the region surrounded by the groove 4 is located on the tip side of the ceramic structure 1 with respect to the highest heat generating portion 10.
  • the portion of the groove portion 4 that is located on the most rear end side of the ceramic structure 1 is located on the tip side of the highest heat generating portion 10.
  • the shape of the groove 4 is curved when viewed in a cross section perpendicular to the surface of the ceramic structure 1. Thereby, it can suppress that the thermal stress produced when the ceramic structure 1 becomes high temperature concentrates on the groove part 4.
  • the groove portion 4 has a gentler inclination on the inner peripheral side than that on the outer peripheral side. As a result, when the gas flows around the heater 100, the gas flowing from the outer peripheral side of the groove portion 4 is moderated on the inner peripheral side, so that the gas can easily stay in the groove portion 4.
  • the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention.
  • the groove 4 may be provided in an annular shape. According to this, it can suppress that the thermal stress produced when the ceramic structure 1 becomes high temperature concentrates on the groove part 4.
  • a convex portion 5 that is continuous along the outer periphery of the groove portion 4 may be formed on the surface of the ceramic structure 1.
  • the gas can be more easily retained in the groove portion 4 when the gas flows around the heater 100.
  • the height of the convex portion 5 is 0.01 mm or more when viewed from the region surrounded by the groove 4. It is formed.
  • the shape of the convex portion 5 when viewed in a cross section perpendicular to the surface of the ceramic structure 1, the shape of the convex portion 5 may be a curved shape. According to this, when gas flows around the heater 100, the gas easily flows into the convex portion 5. As a result, the gas can be efficiently burned inside the convex portion 5.
  • the shape of the convex portion 5 for example, an arc shape or a semi-elliptical shape can be used.
  • a recess 6 may be provided in a region of the surface of the ceramic structure 1 that overlaps the folded portion 21 instead of the groove portion 4 surrounding the folded portion 21.
  • the surface the surface of the part in which the recessed part 6 is provided ( It is possible to bring the bottom surface of the recess 6 closer to the heating resistor 2 than the surrounding surface. Thereby, the temperature of the surface of the part in which the recessed part 6 is provided becomes easy to rise.
  • the concave portion 6 in which the temperature is likely to rise in the vicinity of the maximum heat generating portion 10, the temperature difference between the maximum heat generating portion 10 and the vicinity thereof can be reduced. Thereby, the uneven temperature distribution on the surface of the heater 100 can be reduced. As a result, the long-term reliability of the heater 100 can be improved.
  • the radius of curvature of the outer periphery of the folded portion 21 is 1 mm
  • the recess 6 is formed in a square shape having a depth of 0.1 mm and a side of the outer periphery of 2 mm.
  • the region where the concave portion 6 overlaps is located closer to the tip of the ceramic structure 1 than the highest heat generating portion 10.
  • the portion of the concave portion 6 that is located on the most rear end side of the ceramic structure 1 is located on the tip side of the highest heat generating portion 10.
  • the shape of the recess 6 when viewed in a cross section perpendicular to the surface of the ceramic structure 1, the shape of the recess 6 may be curved. According to this, it can suppress that the thermal stress produced when the ceramic structure 1 becomes high temperature concentrates on the recessed part 6.
  • FIG. 7 when viewed in a cross section perpendicular to the surface of the ceramic structure 1, the shape of the recess 6 may be curved. According to this, it can suppress that the thermal stress produced when the ceramic structure 1 becomes high temperature concentrates on the recessed part 6.
  • the concave portion 61 is also formed on the surface opposite to the surface of the ceramic structure 1 provided with the concave portion 6 so as to overlap the region where the folded portion 21 of the heating resistor 2 faces. May be provided. According to this, even when both surfaces of the heater 100 are used for heating the heating object, the temperature distribution on the surface of the ceramic structure 1 can be further flattened.
  • the shape of the ceramic structure 1 is not limited to the above-described square bar shape, but may be a round bar shape, and the tip may be hemispherical.
  • the folded portion 21 of the heating resistor 2 is not necessarily limited to a semicircular shape as illustrated in each drawing, but is folded at an acute angle or a polygonal shape such as a rectangular shape. It doesn't matter.
  • the folded portion 21 of the heating resistor 2 facing the surface of the ceramic structure 1 is not necessarily required to have the folded portion 21 and the straight portion 22 face parallel to the surface as shown in each drawing. There is no problem even if it faces in a state inclined with respect to the surface.
  • a conductive paste containing a conductive ceramic powder and a resin binder and the like, and a conductive paste that becomes the heating resistor 2 and the power supply line 3 after firing, and an insulating ceramic powder and a resin binder and the like are included, and the ceramic structure 1 after firing.
  • a ceramic paste to be an insulating substrate is prepared.
  • a conductive paste molded body having a predetermined shape to be the heating resistor 2 is formed by an injection molding method or the like using the conductive paste for the heating resistor 2. Then, in a state where the molded body to be the heating resistor 2 is held in the mold, the conductive paste for the feeder 3 is filled in the mold, and the conductive paste having a predetermined shape to be the feeder 3 is molded. Form the body in one piece. As a result, the molded body of the heating resistor 2 and the feeder 3 connected to the heating resistor 2 is held in the mold.
  • the heating resistor 2 and the feeder 3 are made of ceramic paste by using a mold having a groove 4 or a recess 6 in a region of the surface of the ceramic structure 1 facing the folded portion 21 of the heating resistor 1.
  • a mold having a groove 4 or a recess 6 in a region of the surface of the ceramic structure 1 facing the folded portion 21 of the heating resistor 1.
  • a molded body is obtained.
  • the groove portion 4 having a desired shape and size is formed on the surface of the ceramic structure 1.
  • a molded body of the heater 100 having the recess 6 is obtained.
  • the obtained molded body is fired at about 1700 ° C., whereby the heater 100 can be manufactured.
  • the firing is preferably performed in a non-oxidizing gas atmosphere such as hydrogen gas.
  • the heater 100 of the example of the present invention was manufactured as follows. First, a conductive paste containing 50% by mass of tungsten carbide powder, 35% by mass of silicon nitride powder and 15% by mass of a resin binder was injection-molded into a mold to produce a heating resistor 2. Next, in a state where the heating resistor 2 is held in the mold, the above-described conductive paste that becomes the power supply line 3 is filled in the mold, so that the power supply line 3 is connected to the heating resistor 2. Formed.
  • the silicon nitride powder is contained by 85% by mass
  • the ytterbium trioxide as a sintering aid is contained by 10% by mass
  • the tungsten carbide is contained by 5% by mass.
  • the ceramic paste was injection molded into the mold.
  • the heater 100 having a structure in which the heating resistor 2 having the folded portion 21 and the feeder line 3 are embedded in the ceramic structure 1 near the tip of the ceramic structure 1 was formed.
  • a concave portion 6 having a side length of 2.3 mm and a depth of 50 ⁇ m is provided as a sample 1 in a region overlapping the folded portion 21 on the tip side of the main surface (5 mm ⁇ 30 mm) of the ceramic structure 1.
  • a sample was prepared.
  • heaters 100 (samples 2 to 4) having main surfaces different from those of the sample 1 were prepared by preparing molds having various shapes. Each sample had a thickness of 5 mm, a width of 10 mm, and a length of 30 mm, and was different from the sample 1 only in the shape of the main surface.
  • a groove portion 4 having a side length of 2.3 mm, a depth of 50 ⁇ m, and an inner inner wall surface inclined more gently than an outer inner wall surface is provided on the main surface. It was.
  • a groove portion 4 having a side length of 2.3 mm and a depth of 50 ⁇ m was provided on the main surface, and a convex portion 5 having a height of 20 ⁇ m was provided so as to surround the groove portion 4.
  • a groove portion 4 having a side length of 2.3 mm and a depth of 50 ⁇ m is provided on the main surface, and the shape of the surface is a curved surface surrounding the groove portion 4 and the height of the tip portion is 20 ⁇ m. Part 5 was provided.
  • the comparative example 1 whose main surface is flat was prepared as a comparative example.
  • the endurance test was carried out by repeating the cycle of energizing for 30 seconds at the ignited temperature, then raising the temperature of the tip of the ceramic structure to 1200 ° C, and then stopping energization for 60 seconds. did.
  • the heaters 100 of Samples 1 to 4 operated normally even when the number of cycles was 230,000 or more.
  • the heater of Comparative Example 1 had a cycle number of about 60000 and the highest heating portion 10 of the main surface of the ceramic structure 1. A crack occurred in the vicinity.
  • the temperature distribution in the region from the tip of the ceramic structure 1 to the maximum heat generating portion 10 was measured using a radiation thermometer. Specifically, the temperature distribution on the surface of the ceramic structure 1 was measured when the temperature of the tip of the ceramic structure 1 was raised to 1200 ° C. and left for 5 minutes with the voltage applied.
  • the temperature of the highest heating portion of the ceramic structure was 1240 ° C.
  • the temperature of the tip of the ceramic structure was 1200 ° C.
  • the temperature of the maximum heat generating portion 10 was 1250 ° C.
  • the temperature of the tip was 1230 ° C.
  • the temperature of the recess 6 was 1240 ° C.
  • the temperature of the highest heat generating portion 10 was 1250 ° C.
  • the temperature of the tip was 1230 ° C.
  • the temperature of the groove portion 4 was 1240 ° C.
  • the temperature of the highest heat generating portion 10 was 1250 ° C.
  • the temperature of the tip was 1230 ° C.
  • the temperature of the groove portion 4 was 1240 ° C.
  • the temperature of the highest heat generating part 10 was 1250 ° C.
  • the temperature of the tip was 1230 ° C.
  • the temperature of the groove part 4 was 1240 ° C.
  • the heater of Comparative Example 1 had a large temperature difference of 40 ° C. on the main surface of the ceramic structure, whereas the heater 100 of Samples 1 to 4 had a small difference of 20 ° C.
  • the configuration of the heater 100 of the present invention it is possible to reduce the uneven temperature distribution on the main surface of the ceramic structure 1.
  • the possibility of cracks occurring on the main surface of the ceramic structure 1 could be reduced.
  • Samples 2 to 4 and Comparative Example 1 were set inside a test case provided with a gas inlet. The gas continues to flow into the housing, and the time from when the current is supplied to the heaters 100 of the samples 2 to 4 and the heater of the comparative example 1 until the gas is ignited, and after the current is stopped, is extinguished. Investigate the time until. As gas, the gasified diesel fuel was used. As a result, in the heaters 100 of Sample 2 and Sample 3, the time until ignition was within 40 seconds. In contrast, the heater of Comparative Example 1 took 60 seconds to ignite. From this result, it can be seen that the heaters 100 of Sample 2 and Sample 3 have a shorter ignition time of 20 seconds than the heater of Comparative Example 1, and the ignitability is improved.
  • the heater of the sample 2 has the groove portion 4 in which the inner wall surface on the inner side is inclined more gently than the inner wall surface on the outer side, whereby the flow of gas entering from the outer peripheral side of the groove portion 4 is reduced. It is considered that the ignitability is improved because the gas tends to stay in the groove portion 4 by being gentle in the vicinity. Further, regarding the sample 3, it is considered that the ignitability is improved by having the convex portion 5 surrounding the groove portion 4 so that the gas can more easily stay in the groove portion 4.
  • the time required for extinguishing after the end of heat generation was compared for the heater of Comparative Example 1 and the heater 100 of Sample 4, the time required to extinguish the current for the heater of Sample 4 from 70 seconds is 70 seconds.
  • the time to extinguish was about 100 seconds. This is because when the gas flows around the heater 100 by making the shape of the convex portion 5 curved, the gas easily flows into the convex portion 5. It is thought that it was able to burn efficiently.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Resistance Heating (AREA)

Abstract

This heater is provided with a ceramic structure, and a heating resistor buried in the ceramic structure and having a folded portion, and the ceramic structure has a groove portion surrounding the folded portion in a surface which the folded portion faces.

Description

ヒータheater
　本発明は、ヘアアイロン、水加熱用ヒータ、酸素センサ、空燃比センサ、グロープラグ、各種燃焼機器または半導体製造装置等に用いられるヒータに関するものである。 The present invention relates to a heater used in a hair iron, a water heater, an oxygen sensor, an air-fuel ratio sensor, a glow plug, various combustion devices, a semiconductor manufacturing apparatus, or the like.
　ヘアアイロン等に用いられるヒータとしては、例えば、特開２００６－４０８８２号公報（以下、特許文献１という）に記載されたセラミックヒータが挙げられる。特許文献１に記載されたセラミックヒータは、セラミック基体と、セラミック基体の内部に設けられた発熱部と、セラミック基材の内部に設けられて発熱部に接続されたリード部とを備えている。 Examples of heaters used for hair irons include ceramic heaters described in Japanese Patent Application Laid-Open No. 2006-40882 (hereinafter referred to as Patent Document 1). The ceramic heater described in Patent Document 1 includes a ceramic base, a heat generating part provided in the ceramic base, and a lead part provided in the ceramic base and connected to the heat generating part.
　特許文献１に記載のセラミックヒータ（以下、単にヒータともいう）においては、発熱部（発熱抵抗体）は、２つの並んだ直線部とこれらの直線部を繋ぐ折返し部とを有している。このような形状のヒータにおいては、セラミック基体（セラミック構造体）のうち２つの並んだ直線部の間であって折返し部の近傍に位置する部分が特に高温になる傾向にある。そのため、セラミック構造体の表面は、上述の部分に面する領域（以下、最高発熱部という）が最も高温になるとともに、最高発熱部を中心として、最高発熱部から離れるにつれて温度が下がっていくような温度分布になっていた。このように、セラミック構造体の表面に偏った温度分布が生じる場合には、ヒータを繰り返し使用することによって、セラミック構造体の表面にクラックが生じる可能性があった。その結果、ヒータの長期信頼性を向上させることが困難であった。 In the ceramic heater described in Patent Document 1 (hereinafter, also simply referred to as a heater), the heat generating portion (heat generating resistor) has two lined linear portions and a folded portion connecting these linear portions. In the heater having such a shape, a portion located between the two linear portions arranged in the ceramic base body (ceramic structure) and in the vicinity of the turned-up portion tends to have a particularly high temperature. For this reason, the surface of the ceramic structure has the highest temperature in the region facing the above-described portion (hereinafter referred to as the highest heat generating portion), and the temperature decreases as the distance from the highest heat generating portion increases with the highest heat generating portion as the center. The temperature distribution was correct. As described above, when a biased temperature distribution occurs on the surface of the ceramic structure, cracks may occur on the surface of the ceramic structure by repeatedly using the heater. As a result, it has been difficult to improve the long-term reliability of the heater.
　本発明の一態様のヒータは、セラミック構造体と、該セラミック構造体に埋設された折返し部を有する発熱抵抗体とを具備し、前記セラミック構造体は、前記折返し部が面している表面に前記折返し部を囲む溝部を有する。 The heater according to one aspect of the present invention includes a ceramic structure and a heating resistor having a folded portion embedded in the ceramic structure, and the ceramic structure has a surface facing the folded portion. A groove portion surrounding the folded portion;
　本発明の別の態様のヒータは、セラミック構造体と、該セラミック構造体に埋設された折返し部を有する発熱抵抗体とを具備し、前記セラミック構造体は、前記折返し部が面している表面のうち前記折返し部に重なる領域に凹部を有する。 A heater according to another aspect of the present invention includes a ceramic structure and a heating resistor having a folded portion embedded in the ceramic structure, and the ceramic structure has a surface facing the folded portion. Among these, it has a recessed part in the area | region which overlaps the said folding | turning part.
本発明の一実施形態のヒータを示す斜視図である。It is a perspective view which shows the heater of one Embodiment of this invention. （ａ）は図１に示したヒータの領域Ａを拡大した部分拡大図であり、（ｂ）はＢ－Ｂ’断面の断面図である。(A) is the elements on larger scale which expanded the area | region A of the heater shown in FIG. 1, (b) is sectional drawing of a B-B 'cross section. 本発明の変形例のヒータを示す部分拡大図である。It is the elements on larger scale which show the heater of the modification of this invention. 本発明の変形例のヒータを示す断面図である。It is sectional drawing which shows the heater of the modification of this invention. 本発明の変形例のヒータを示す断面図である。It is sectional drawing which shows the heater of the modification of this invention. 本発明の変形例のヒータを示す部分拡大図（ａ）とＣ－Ｃ’断面の断面図（ｂ）である。FIG. 7 is a partially enlarged view (a) showing a heater according to a modification of the present invention and a sectional view (b) taken along the C-C ′ section. 本発明の変形例のヒータを示す断面図である。It is sectional drawing which shows the heater of the modification of this invention. 本発明の変形例のヒータを示す断面図である。It is sectional drawing which shows the heater of the modification of this invention.
　以下、本発明の一実施形態のヒータ１００について図面を参照して詳細に説明する。 Hereinafter, the heater 100 according to an embodiment of the present invention will be described in detail with reference to the drawings.
　図１は、本発明の一実施形態のヒータ１００を示す斜視図である。図２（ａ）は、図１に示したヒータ１００の領域Ａを拡大した部分拡大図であり、図２（ｂ）はＢ－Ｂ’断面の断面図である。図１に示すように、本発明の一実施形態のヒータ１００は、セラミック構造体１と発熱抵抗体２と給電線３とリード端子７とを備えている。なお、図１においては、発熱抵抗体２と給電線３とを、セラミック構造体１を透視して破線で示している。ヒータ１００は、例えば、ヘアアイロン、水加熱用ヒータ、酸素センサ、空燃比センサ、グロープラグまたは半導体製造装置等に用いられる。 FIG. 1 is a perspective view showing a heater 100 according to an embodiment of the present invention. 2A is a partially enlarged view in which the region A of the heater 100 shown in FIG. 1 is enlarged, and FIG. 2B is a cross-sectional view taken along the line B-B ′. As shown in FIG. 1, a heater 100 according to an embodiment of the present invention includes a ceramic structure 1, a heating resistor 2, a power supply line 3, and a lead terminal 7. In FIG. 1, the heating resistor 2 and the power supply line 3 are indicated by broken lines through the ceramic structure 1. The heater 100 is used in, for example, a hair iron, a water heating heater, an oxygen sensor, an air-fuel ratio sensor, a glow plug, or a semiconductor manufacturing apparatus.
　セラミック構造体１は、発熱抵抗体２および給電線３を内部に保持するための部材である。セラミック構造体１の内部に発熱抵抗体２および給電線３が設けられることによって、発熱抵抗体２および給電線３の耐環境性を向上できる。セラミック構造体１は、棒状の部材である。セラミック構造体１は、アルミナ、窒化珪素、窒化アルミニウムまたは炭化珪素等のセラミック材料から成る。セラミック構造体１は、例えば角棒状であれば、この場合には例えば、外周の短辺の長さが２５ｍｍであり、長辺の長さが２５ｍｍであり、長手方向の長さが５０ｍｍである。 The ceramic structure 1 is a member for holding the heating resistor 2 and the feeder 3 inside. By providing the heating resistor 2 and the power supply line 3 inside the ceramic structure 1, the environmental resistance of the heating resistor 2 and the power supply line 3 can be improved. The ceramic structure 1 is a rod-shaped member. The ceramic structure 1 is made of a ceramic material such as alumina, silicon nitride, aluminum nitride, or silicon carbide. If the ceramic structure 1 is, for example, a square bar shape, in this case, for example, the length of the short side of the outer periphery is 25 mm, the length of the long side is 25 mm, and the length in the longitudinal direction is 50 mm. .
　発熱抵抗体２は、通電することによって熱を発する部材である。発熱抵抗体２は、セラミック構造体１に埋設されている。発熱抵抗体２は、セラミック構造体１の外周の長辺と長手方向の辺とを含む面（以下、主面という）に面するように配置されている。図２に示すように、発熱抵抗体２は、２つの並んだ直線部２２と、これらの直線部２２を繋ぐ、外周および内周の形状が半円状の折返し部２１とを有している。なお、図２においても、セラミック構造体１を透視して破線で発熱抵抗体２を示している。発熱抵抗体２は、折返し部２１がセラミック構造体１の先端近くに設けられるとともに、折返し部２１の端部から後端側に向かって直線部２２が設けられている。発熱抵抗体２は、炭化タングステン等の導電性のセラミック材料から成る。発熱抵抗体２は、例えば、線幅が０．２～１．５ｍｍであり、厚みが０．３～３ｍｍである。折返し部２１の曲率半径は、例えば、内周が０．１５～１ｍｍであり、外周が０．５～２ｍｍである。発熱抵抗体２で発せられた熱は、セラミック構造体１の内部を伝導し、セラミック構造体１の表面から外部に発せられる。 The heating resistor 2 is a member that generates heat when energized. The heating resistor 2 is embedded in the ceramic structure 1. The heating resistor 2 is disposed so as to face a surface (hereinafter, referred to as a main surface) including a long side of the outer periphery of the ceramic structure 1 and a side in the longitudinal direction. As shown in FIG. 2, the heating resistor 2 has two linear portions 22 that are arranged side by side, and a folded portion 21 that connects these linear portions 22 and has a semicircular shape on the outer periphery and inner periphery. . In FIG. 2 as well, the heating resistor 2 is indicated by a broken line through the ceramic structure 1. In the heating resistor 2, the folded portion 21 is provided near the front end of the ceramic structure 1, and the linear portion 22 is provided from the end portion of the folded portion 21 toward the rear end side. The heating resistor 2 is made of a conductive ceramic material such as tungsten carbide. The heating resistor 2 has, for example, a line width of 0.2 to 1.5 mm and a thickness of 0.3 to 3 mm. The radius of curvature of the folded portion 21 is, for example, 0.15 to 1 mm on the inner periphery and 0.5 to 2 mm on the outer periphery. The heat generated by the heating resistor 2 is conducted inside the ceramic structure 1 and is emitted from the surface of the ceramic structure 1 to the outside.
　図１に戻って、給電線３は、リード端子７と共に、発熱抵抗体２をセラミック構造体１の外部の電源（図示せず）に電気的に接続するための一対の配線部材である。給電線３は、大部分がセラミック構造体１に埋設されていて、一端が発熱抵抗体２に電気的に接続されている。すなわち、それぞれの給電線３の一端は発熱抵抗体２の別々の端部に接続されている。一方、それぞれの給電線３の他端は、外部の電源に接続するために、セラミック構造体１の後端側の表面に引き出されて、別々のリード端子７が接続されている。給電線３は、セラミック構造体１の内部を引き回す配線として線状に形成されている。給電線３は、例えば炭化タングステン等の導電性のセラミック材料から成り、発熱抵抗体２よりも低抵抗の配線として形成されている。給電線３の線幅は、例えば０．２～２ｍｍであり、厚みは、例えば０．３～４μｍである。 Returning to FIG. 1, the feeder 3 is a pair of wiring members for electrically connecting the heating resistor 2 together with the lead terminal 7 to a power source (not shown) outside the ceramic structure 1. Most of the feeder 3 is embedded in the ceramic structure 1 and one end is electrically connected to the heating resistor 2. That is, one end of each feeder 3 is connected to a separate end of the heating resistor 2. On the other hand, the other end of each power supply line 3 is drawn out to the surface on the rear end side of the ceramic structure 1 to be connected to an external power source, and separate lead terminals 7 are connected thereto. The power supply line 3 is formed in a linear shape as a wiring that runs around the inside of the ceramic structure 1. The feeder 3 is made of a conductive ceramic material such as tungsten carbide, and is formed as a wiring having a resistance lower than that of the heating resistor 2. The line width of the feeder line 3 is, for example, 0.2 to 2 mm, and the thickness is, for example, 0.3 to 4 μm.
　リード端子７は、給電線３を外部の電源に電気的に接続するための棒状の導電部材である。リード端子７は、セラミック構造体１の発熱抵抗体２が設けられている側とは逆側の表面に引き出されたそれぞれの給電線３に接合されている。リード端子７は、例えば、ニッケルから成る。リード端子７と給電線３との接合には、例えばろう材が用いられる。ろう材としては、例えば銀ろう等が用いられる。リード端子７の寸法は、例えば、幅が０．２～２ｍｍ、厚さが０．２～２ｍｍ、長さが１０ｍｍ以上である。 The lead terminal 7 is a rod-shaped conductive member for electrically connecting the feeder 3 to an external power source. The lead terminal 7 is joined to each power supply line 3 drawn out on the surface of the ceramic structure 1 opposite to the side where the heating resistor 2 is provided. The lead terminal 7 is made of nickel, for example. For example, a brazing material is used for joining the lead terminal 7 and the feeder 3. As the brazing material, for example, silver brazing is used. The dimensions of the lead terminal 7 are, for example, a width of 0.2 to 2 mm, a thickness of 0.2 to 2 mm, and a length of 10 mm or more.
　図２（ａ）に戻って、本実施形態のヒータ１００においては、発熱抵抗体２が、２つの並んだ直線部２２とこれら直線部２２を繋ぐ折返し部２１とを有している。このような形状のヒータ１００においては、セラミック構造体１のうち２つの並んだ直線部２２の間であって折返し部２１の近傍に位置する部分が特に高温になる。そのため、セラミック構造体１の表面は、上述の部分に面する領域（最高発熱部１０）が特に高温になる。なお、図２（ａ）においては、最高発熱部１０を二点鎖線で示している。 2A, in the heater 100 of the present embodiment, the heating resistor 2 has two linear portions 22 that are arranged side by side and a folded portion 21 that connects these linear portions 22. In the heater 100 having such a shape, a portion located between the two linear portions 22 arranged in the ceramic structure 1 and in the vicinity of the turned-up portion 21 is particularly high in temperature. Therefore, as for the surface of the ceramic structure 1, the area | region (maximum heat generating part 10) which faces the above-mentioned part becomes especially high temperature. In FIG. 2A, the highest heat generating portion 10 is indicated by a two-dot chain line.
　そこで、本実施形態のヒータ１００においては、セラミック構造体１は、最高発熱部１０よりも先端側の領域の表面に、発熱抵抗体２の折返し部２１を囲む溝部４を有している。溝部４は、本実施形態では折返し部２１を囲むように四角形状の枠状に設けられている。このため、溝部４が設けられている部分の表面（溝部４の底面）を周囲の表面よりも発熱抵抗体２に近付けることができる。これにより、溝部４が設けられている部分の表面の温度が上昇しやすくなる。このように温度が上昇しやすくなる溝部４を最高発熱部１０の近傍に設けることによって、最高発熱部１０とその近傍との間の温度差を小さくすることができる。これにより、ヒータ１００の表面の温度分布の偏りを低減できる。その結果、ヒータ１００の長期信頼性を向上させることができる。 Therefore, in the heater 100 of the present embodiment, the ceramic structure 1 has the groove portion 4 surrounding the folded portion 21 of the heating resistor 2 on the surface of the region on the tip side of the highest heating portion 10. In this embodiment, the groove part 4 is provided in the shape of a square frame so as to surround the folded part 21. For this reason, the surface (bottom surface of the groove part 4) of the part in which the groove part 4 is provided can be brought closer to the heating resistor 2 than the surrounding surface. Thereby, the temperature of the surface of the part in which the groove part 4 is provided becomes easy to rise. Thus, by providing the groove part 4 in which the temperature is likely to rise in the vicinity of the maximum heat generating part 10, the temperature difference between the maximum heat generating part 10 and the vicinity thereof can be reduced. Thereby, the uneven temperature distribution on the surface of the heater 100 can be reduced. As a result, the long-term reliability of the heater 100 can be improved.
　このような溝部４の寸法は、折返し部２１の外周の曲率半径が１ｍｍの場合には、例えば、幅が０．１５ｍｍ、深さが０．１ｍｍであり、外周の一辺が２ｍｍの正方形状に形成される。 When the radius of curvature of the outer periphery of the folded portion 21 is 1 mm, such a dimension of the groove portion 4 is, for example, a square shape having a width of 0.15 mm, a depth of 0.1 mm, and an outer peripheral side of 2 mm. It is formed.
　さらに、本実施形態のヒータ１００においては、溝部４に囲まれる領域が、最高発熱部１０よりもセラミック構造体１の先端側に位置している。言い換えると、溝部４のうちセラミック構造体１の最も後端側に位置する部分が最高発熱部１０よりも先端側に位置している。これにより、加熱対象物が設けられるセラミック構造体１の先端側において、温度分布の偏りをさらに低減できる。なお、最高発熱部１０の位置は、例えば放射温度計を用いてセラミック構造体１の表面の温度を測定することによって確認できる。 Furthermore, in the heater 100 of the present embodiment, the region surrounded by the groove 4 is located on the tip side of the ceramic structure 1 with respect to the highest heat generating portion 10. In other words, the portion of the groove portion 4 that is located on the most rear end side of the ceramic structure 1 is located on the tip side of the highest heat generating portion 10. Thereby, in the front end side of the ceramic structure 1 in which a heating target object is provided, the deviation of temperature distribution can further be reduced. In addition, the position of the highest heat generation part 10 can be confirmed by measuring the temperature of the surface of the ceramic structure 1 using a radiation thermometer, for example.
　また、図２（ｂ）に示すように、セラミック構造体１の表面に垂直な断面で見たときに、溝部４の形状が曲線状であることが好ましい。これにより、セラミック構造体１が高温になったときに生じる熱応力が溝部４に集中することを抑制できる。 Further, as shown in FIG. 2 (b), it is preferable that the shape of the groove 4 is curved when viewed in a cross section perpendicular to the surface of the ceramic structure 1. Thereby, it can suppress that the thermal stress produced when the ceramic structure 1 becomes high temperature concentrates on the groove part 4. FIG.
　さらに、溝部４は、内周側の傾斜が外周側の傾斜に比べて緩やかになっていることが好ましい。これにより、ヒータ１００の周囲にガスを流したときに、溝部４の外周側から入り込んだガスの流れを内周側で穏やかにすることによって、ガスを溝部４に留まりやすくすることができる。 Furthermore, it is preferable that the groove portion 4 has a gentler inclination on the inner peripheral side than that on the outer peripheral side. As a result, when the gas flows around the heater 100, the gas flowing from the outer peripheral side of the groove portion 4 is moderated on the inner peripheral side, so that the gas can easily stay in the groove portion 4.
　なお、本発明は上述の実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲において種々の変更、改良等が可能である。例えば、図３に示すように、溝部４が円環状に設けられていてもよい。これによれば、セラミック構造体１が高温になったときに生じる熱応力が、溝部４に集中することを抑制できる。 It should be noted that the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention. For example, as shown in FIG. 3, the groove 4 may be provided in an annular shape. According to this, it can suppress that the thermal stress produced when the ceramic structure 1 becomes high temperature concentrates on the groove part 4.
　また、図４に断面図で示すように、セラミック構造体１の表面に、溝部４の外周に沿って連続した凸部５が形成されていてもよい。凸部５によって溝部４を囲うことによって、ヒータ１００の周囲にガスを流したときに、ガスを溝部４にさらに留まりやすくすることができる。例えば、溝部４に囲まれた領域から見た溝部４の深さが０．１ｍｍである場合には、凸部５の高さは、溝部４に囲まれた領域から見て０．０１ｍｍ以上に形成される。 Further, as shown in a sectional view in FIG. 4, a convex portion 5 that is continuous along the outer periphery of the groove portion 4 may be formed on the surface of the ceramic structure 1. By enclosing the groove portion 4 with the convex portion 5, the gas can be more easily retained in the groove portion 4 when the gas flows around the heater 100. For example, when the depth of the groove 4 viewed from the region surrounded by the groove 4 is 0.1 mm, the height of the convex portion 5 is 0.01 mm or more when viewed from the region surrounded by the groove 4. It is formed.
　また、図５に示すように、セラミック構造体１の表面に垂直な断面で見たときに、凸部５の形状が曲線状であってもよい。これによれば、ヒータ１００の周囲にガスを流したときに、ガスが凸部５の内側に流れ込みやすくなる。その結果、凸部５の内側でガスを効率よく燃焼させることができる。凸部５の形状としては、例えば、円弧状または半楕円形状等を用いることができる。 Further, as shown in FIG. 5, when viewed in a cross section perpendicular to the surface of the ceramic structure 1, the shape of the convex portion 5 may be a curved shape. According to this, when gas flows around the heater 100, the gas easily flows into the convex portion 5. As a result, the gas can be efficiently burned inside the convex portion 5. As the shape of the convex portion 5, for example, an arc shape or a semi-elliptical shape can be used.
　また、図６（ａ）および（ｂ）に示すように、セラミック構造体１の表面のうち折返し部２１に重なる領域に、折返し部２１を囲む溝部４に代えて凹部６が設けられていてもよい。このように、セラミック構造体１のうち折返し部２１の面している表面であって折返し部２１に重なる領域に凹部６を有していることによって、凹部６が設けられている部分の表面（凹部６の底面）をその周囲の表面よりも発熱抵抗体２に近付けることができる。これにより、凹部６が設けられている部分の表面の温度が上昇しやすくなる。このように温度が上昇しやすくなる凹部６を最高発熱部１０の近傍に設けることによって、最高発熱部１０とその近傍との間の温度差を小さくすることができる。これにより、ヒータ１００の表面の温度分布の偏りを低減できる。その結果、ヒータ１００の長期信頼性を向上させることができる。凹部６の寸法は、折返し部２１の外周の曲率半径が１ｍｍの場合には、例えば、深さが０．１ｍｍであり、外周の一辺が２ｍｍの正方形状に形成される。 Further, as shown in FIGS. 6A and 6B, a recess 6 may be provided in a region of the surface of the ceramic structure 1 that overlaps the folded portion 21 instead of the groove portion 4 surrounding the folded portion 21. Good. Thus, by having the recessed part 6 in the area | region which is the surface which the folding | returning part 21 faces among the ceramic structures 1 and overlaps with the turned-back part 21, the surface (the surface of the part in which the recessed part 6 is provided ( It is possible to bring the bottom surface of the recess 6 closer to the heating resistor 2 than the surrounding surface. Thereby, the temperature of the surface of the part in which the recessed part 6 is provided becomes easy to rise. Thus, by providing the concave portion 6 in which the temperature is likely to rise in the vicinity of the maximum heat generating portion 10, the temperature difference between the maximum heat generating portion 10 and the vicinity thereof can be reduced. Thereby, the uneven temperature distribution on the surface of the heater 100 can be reduced. As a result, the long-term reliability of the heater 100 can be improved. For example, when the radius of curvature of the outer periphery of the folded portion 21 is 1 mm, the recess 6 is formed in a square shape having a depth of 0.1 mm and a side of the outer periphery of 2 mm.
　さらに、図６に示すヒータ１００は、凹部６が重なっている領域が、最高発熱部１０よりもセラミック構造体１の先端側に位置している。言い換えると、凹部６のうちセラミック構造体１の最も後端側に位置する部分が最高発熱部１０よりも先端側に位置している。これにより、加熱対象物が設けられるセラミック構造体１の先端側において、温度分布の偏りをさらに低減できる。 Furthermore, in the heater 100 shown in FIG. 6, the region where the concave portion 6 overlaps is located closer to the tip of the ceramic structure 1 than the highest heat generating portion 10. In other words, the portion of the concave portion 6 that is located on the most rear end side of the ceramic structure 1 is located on the tip side of the highest heat generating portion 10. Thereby, in the front end side of the ceramic structure 1 in which a heating target object is provided, the deviation of temperature distribution can further be reduced.
　また、図７に示すように、セラミック構造体１の表面に垂直な断面で見たときに、凹部６の形状が曲線状であってもよい。これによれば、セラミック構造体１が高温になったときに生じる熱応力が、凹部６に集中することを抑制できる。 Further, as shown in FIG. 7, when viewed in a cross section perpendicular to the surface of the ceramic structure 1, the shape of the recess 6 may be curved. According to this, it can suppress that the thermal stress produced when the ceramic structure 1 becomes high temperature concentrates on the recessed part 6. FIG.
　また、図８に示すように、凹部６が設けられたセラミック構造体１の表面とは反対側の表面においても、発熱抵抗体２の折返し部２１が面している領域に重なるように凹部６１が設けられていてもよい。これによれば、ヒータ１００の両面を加熱対象物の加熱に使用する場合においても、セラミック構造体１の表面の温度分布をさらに平坦化することができる。 Further, as shown in FIG. 8, the concave portion 61 is also formed on the surface opposite to the surface of the ceramic structure 1 provided with the concave portion 6 so as to overlap the region where the folded portion 21 of the heating resistor 2 faces. May be provided. According to this, even when both surfaces of the heater 100 are used for heating the heating object, the temperature distribution on the surface of the ceramic structure 1 can be further flattened.
　また、セラミック構造体１の形状は、上述した角棒状に限られず、丸棒状であってもよく、さらに先端部が半球状になっていても構わない。 Further, the shape of the ceramic structure 1 is not limited to the above-described square bar shape, but may be a round bar shape, and the tip may be hemispherical.
　また、発熱抵抗体２の折返し部２１は、必ずしも各図に図示したように半円状に折り返しているものに限られず、鋭角に、あるいは矩形状等の多角形状に折り返しているものであっても構わない。 In addition, the folded portion 21 of the heating resistor 2 is not necessarily limited to a semicircular shape as illustrated in each drawing, but is folded at an acute angle or a polygonal shape such as a rectangular shape. It doesn't matter.
　また、セラミック構造体１の表面に面している発熱抵抗体２の折返し部２１は、必ずしも各図に図示したように折返し部２１および直線部２２が表面に対して平行に面している必要はなく、表面に対して傾いた状態で面していても差し支えない。 Further, the folded portion 21 of the heating resistor 2 facing the surface of the ceramic structure 1 is not necessarily required to have the folded portion 21 and the straight portion 22 face parallel to the surface as shown in each drawing. There is no problem even if it faces in a state inclined with respect to the surface.
　次に、本実施形態のヒータ１００の製造方法の一例について説明する。まず、導電性セラミック粉末および樹脂バインダー等を含み、焼成後に発熱抵抗体２および給電線３となる導電性ペーストを作製するとともに、絶縁性セラミック粉末および樹脂バインダー等を含み、焼成後にセラミック構造体１としての絶縁基体となるセラミックペーストを作製する。 Next, an example of a method for manufacturing the heater 100 of this embodiment will be described. First, a conductive paste containing a conductive ceramic powder and a resin binder and the like, and a conductive paste that becomes the heating resistor 2 and the power supply line 3 after firing, and an insulating ceramic powder and a resin binder and the like are included, and the ceramic structure 1 after firing. A ceramic paste to be an insulating substrate is prepared.
　次に、発熱抵抗体２用の導電性ペーストを用いて射出成形法等によって、発熱抵抗体２となる所定形状の導電性ペーストの成形体を形成する。そして、発熱抵抗体２となる成形体を金型内に保持した状態で、給電線３用の導電性ペーストを金型内に充填して、給電線３となる所定形状の導電性ペーストの成形体を一体的に形成する。これにより、発熱抵抗体２とこの発熱抵抗体２に接続された給電線３との成形体が、金型内に保持された状態となる。 Next, a conductive paste molded body having a predetermined shape to be the heating resistor 2 is formed by an injection molding method or the like using the conductive paste for the heating resistor 2. Then, in a state where the molded body to be the heating resistor 2 is held in the mold, the conductive paste for the feeder 3 is filled in the mold, and the conductive paste having a predetermined shape to be the feeder 3 is molded. Form the body in one piece. As a result, the molded body of the heating resistor 2 and the feeder 3 connected to the heating resistor 2 is held in the mold.
　次に、金型内に発熱抵抗体２および給電線３の成形体を保持した状態で、金型の一部をセラミック構造体１の成形用のものに取り替えた後に、金型内にセラミック構造体１用のセラミックペーストを充填する。 Next, after holding the molded body of the heating resistor 2 and the power supply line 3 in the mold, a part of the mold is replaced with one for molding the ceramic structure 1, and then the ceramic structure is formed in the mold. Fill the body 1 with ceramic paste.
　このとき、セラミック構造体１の表面のうち発熱抵抗体１の折返し部２１が面する領域に溝部４または凹部６ができる金型を使用することで、発熱抵抗体２および給電線３がセラミックペーストの成形体で覆われ、セラミック構造体１の表面のうち発熱抵抗体２の折返し部２１が面している部分に折返し部２１を囲む溝部４または折返し部２１に重なる凹部６を有するヒータ１００の成形体が得られる。そして、金型脱型時の押し出しピンの押し出し圧力を高くする方法や、成形体の主面を切削する方法を用いることによって、セラミック構造体１の表面に所望の形状・大きさの溝部４または凹部６を有するヒータ１００の成形体が得られる。 At this time, the heating resistor 2 and the feeder 3 are made of ceramic paste by using a mold having a groove 4 or a recess 6 in a region of the surface of the ceramic structure 1 facing the folded portion 21 of the heating resistor 1. Of the heater 100 having a groove portion 4 surrounding the folded portion 21 or a recessed portion 6 overlapping the folded portion 21 in a portion of the surface of the ceramic structure 1 facing the folded portion 21 of the heating resistor 2. A molded body is obtained. Then, by using a method of increasing the extrusion pressure of the extrusion pin at the time of mold removal or a method of cutting the main surface of the molded body, the groove portion 4 having a desired shape and size is formed on the surface of the ceramic structure 1. A molded body of the heater 100 having the recess 6 is obtained.
　次に、得られた成形体を１７００℃程度で焼成することにより、ヒータ１００を作製することができる。なお、焼成は水素ガス等の非酸化性ガス雰囲気中で行なうことが好ましい。 Next, the obtained molded body is fired at about 1700 ° C., whereby the heater 100 can be manufactured. The firing is preferably performed in a non-oxidizing gas atmosphere such as hydrogen gas.
　本発明の実施例のヒータ１００を以下のようにして作製した。まず、炭化タングステン粉末を５０質量％、窒化珪素粉末を３５質量％および樹脂バインダーを１５質量％含む導電性ペーストを、金型内に射出成形して発熱抵抗体２を作製した。次に、この発熱抵抗体２を金型内に保持した状態で、給電線３となる上記の導電性ペーストを金型内に充填することにより、発熱抵抗体２に接続させて給電線３を形成した。 The heater 100 of the example of the present invention was manufactured as follows. First, a conductive paste containing 50% by mass of tungsten carbide powder, 35% by mass of silicon nitride powder and 15% by mass of a resin binder was injection-molded into a mold to produce a heating resistor 2. Next, in a state where the heating resistor 2 is held in the mold, the above-described conductive paste that becomes the power supply line 3 is filled in the mold, so that the power supply line 3 is connected to the heating resistor 2. Formed.
　次に、発熱抵抗体２および給電線３を金型内に保持した状態で、窒化珪素粉末を８５質量％、焼結助剤として三酸化二イッテルビウムを１０質量％および炭化タングステンを５質量％含むセラミックペーストを、金型内に射出成形した。これにより、セラミック構造体１の中にセラミック構造体１の先端部近くに折返し部２１を有する発熱抵抗体２および給電線３が埋設された構成のヒータ１００を形成した。 Next, in a state where the heating resistor 2 and the feeder 3 are held in the mold, the silicon nitride powder is contained by 85% by mass, the ytterbium trioxide as a sintering aid is contained by 10% by mass, and the tungsten carbide is contained by 5% by mass. The ceramic paste was injection molded into the mold. As a result, the heater 100 having a structure in which the heating resistor 2 having the folded portion 21 and the feeder line 3 are embedded in the ceramic structure 1 near the tip of the ceramic structure 1 was formed.
　ここで、試料１としてセラミック構造体１の主面（５ｍｍ×３０ｍｍ）の先端側であって折返し部２１に重なる領域に、１辺の長さが２．３ｍｍで深さ５０μｍの凹部６を設けたサンプルを作製した。また、種々の形状の金型を用意して、試料１とは異なる主面を有するヒータ１００（試料２～４）を作製した。各試料の寸法は厚みが５ｍｍ、幅が１０ｍｍ、長さが３０ｍｍで、試料１とは主面の形状だけが異なっているものとした。 Here, a concave portion 6 having a side length of 2.3 mm and a depth of 50 μm is provided as a sample 1 in a region overlapping the folded portion 21 on the tip side of the main surface (5 mm × 30 mm) of the ceramic structure 1. A sample was prepared. Also, heaters 100 (samples 2 to 4) having main surfaces different from those of the sample 1 were prepared by preparing molds having various shapes. Each sample had a thickness of 5 mm, a width of 10 mm, and a length of 30 mm, and was different from the sample 1 only in the shape of the main surface.
　具体的には、試料２では、主面に、１辺の長さが２．３ｍｍ、深さが５０μｍで、内側の内壁面が外側の内壁面よりも緩やかに傾斜している溝部４を設けた。試料３では、主面に、１辺の長さが２．３ｍｍ、深さが５０μｍの溝部４を設け、さらに溝部４を囲むように高さが２０μｍの凸部５を設けた。試料４では、主面に、１辺の長さが２．３ｍｍ、深さが５０μｍの溝部４を設け、溝部４を囲むように表面の形状が曲面であり先端部の高さが２０μｍの凸部５を設けた。また、比較例として、主面が平坦である比較例１を準備した。 Specifically, in the sample 2, a groove portion 4 having a side length of 2.3 mm, a depth of 50 μm, and an inner inner wall surface inclined more gently than an outer inner wall surface is provided on the main surface. It was. In the sample 3, a groove portion 4 having a side length of 2.3 mm and a depth of 50 μm was provided on the main surface, and a convex portion 5 having a height of 20 μm was provided so as to surround the groove portion 4. In the sample 4, a groove portion 4 having a side length of 2.3 mm and a depth of 50 μm is provided on the main surface, and the shape of the surface is a curved surface surrounding the groove portion 4 and the height of the tip portion is 20 μm. Part 5 was provided. Moreover, the comparative example 1 whose main surface is flat was prepared as a comparative example.
　次に、得られた試料１～４および比較例１を円筒状の炭素製の型に入れた後、窒素ガスから成る非酸化性ガス雰囲気中で、１６５０℃～１７８０℃の温度および３０ＭＰａ～５０ＭＰａの圧力でホットプレスを行なって焼結した。 Next, after putting the obtained samples 1 to 4 and Comparative Example 1 into a cylindrical carbon mold, in a non-oxidizing gas atmosphere composed of nitrogen gas, a temperature of 1650 ° C. to 1780 ° C. and 30 MPa to 50 MPa Sintered by hot pressing at a pressure of.
　そして、本発明の実施例である試料１～４のヒータ１００について、比較例１のヒータとの比較を行なうことによって、耐久性が向上しているかどうかを確認した。 Then, it was confirmed whether or not the durability of the heaters 100 of the samples 1 to 4 according to the example of the present invention was improved by comparing with the heater of the comparative example 1.
　具体的には、ガス暖房機に試料をセットし、暖房機が着火する温度を調べた。その結果に基づき、着火した温度にて３０秒間通電した後にセラミック構造体の先端の温度が１２００℃になるまで昇温し、その後、６０秒間通電を停止するサイクルを繰り返すことによって、耐久試験を実施した。 Specifically, a sample was set in a gas heater, and the temperature at which the heater ignited was examined. Based on the results, the endurance test was carried out by repeating the cycle of energizing for 30 seconds at the ignited temperature, then raising the temperature of the tip of the ceramic structure to 1200 ° C, and then stopping energization for 60 seconds. did.
　その結果、試料１～４のヒータ１００ではサイクル数が２３００００以上でも正常に動作したが、比較例１のヒータでは、サイクル数が約６００００でセラミック構造体１の主面のうち最高発熱部１０の近傍にクラックが発生した。 As a result, the heaters 100 of Samples 1 to 4 operated normally even when the number of cycles was 230,000 or more. However, the heater of Comparative Example 1 had a cycle number of about 60000 and the highest heating portion 10 of the main surface of the ceramic structure 1. A crack occurred in the vicinity.
　また、他の評価試験として、放射温度計を用いてセラミック構造体１の先端から最高発熱部１０までの領域の温度分布を測定した。具体的には、セラミック構造体１の先端の温度が１２００℃になるまで昇温した後に電圧を印加したまま５分間放置したときのセラミック構造体１の表面の温度分布を測定した。 As another evaluation test, the temperature distribution in the region from the tip of the ceramic structure 1 to the maximum heat generating portion 10 was measured using a radiation thermometer. Specifically, the temperature distribution on the surface of the ceramic structure 1 was measured when the temperature of the tip of the ceramic structure 1 was raised to 1200 ° C. and left for 5 minutes with the voltage applied.
　その結果、比較例１のヒータでは、セラミック構造体の最高発熱部の温度が１２４０℃であり、セラミック構造体の先端の温度が１２００℃であった。これに対して、試料１のヒータ１００では、最高発熱部１０の温度が１２５０℃であり、先端の温度が１２３０℃、凹部６の温度が１２４０℃であった。また、試料２のヒータ１００では、最高発熱部１０の温度が１２５０℃であり、先端の温度が１２３０℃、溝部４の温度が１２４０℃であった。また、試料３のヒータ１００では、最高発熱部１０の温度が１２５０℃であり、先端の温度が１２３０℃、溝部４の温度が１２４０℃であった。また、試料４のヒータ１００では、最高発熱部１０の温度が１２５０℃であり、先端の温度が１２３０℃、溝部４の温度が１２４０℃であった。 As a result, in the heater of Comparative Example 1, the temperature of the highest heating portion of the ceramic structure was 1240 ° C., and the temperature of the tip of the ceramic structure was 1200 ° C. On the other hand, in the heater 100 of the sample 1, the temperature of the maximum heat generating portion 10 was 1250 ° C., the temperature of the tip was 1230 ° C., and the temperature of the recess 6 was 1240 ° C. Further, in the heater 100 of the sample 2, the temperature of the highest heat generating portion 10 was 1250 ° C., the temperature of the tip was 1230 ° C., and the temperature of the groove portion 4 was 1240 ° C. Further, in the heater 100 of the sample 3, the temperature of the highest heat generating portion 10 was 1250 ° C., the temperature of the tip was 1230 ° C., and the temperature of the groove portion 4 was 1240 ° C. Moreover, in the heater 100 of the sample 4, the temperature of the highest heat generating part 10 was 1250 ° C., the temperature of the tip was 1230 ° C., and the temperature of the groove part 4 was 1240 ° C.
　この結果から分かるように、比較例１のヒータではセラミック構造体の主面における温度差が４０℃と大きかったのに対して、試料１～４のヒータ１００ではその差が２０℃と小さかった。これにより、本発明のヒータ１００の構成を採用することによって、セラミック構造体１の主面における温度分布の偏りを低減できることが確認できた。また、その結果、ヒータ１００を繰り返し使用したときに、セラミック構造体１の主面にクラックが発生する可能性を低減できることが分かった。 As can be seen from this result, the heater of Comparative Example 1 had a large temperature difference of 40 ° C. on the main surface of the ceramic structure, whereas the heater 100 of Samples 1 to 4 had a small difference of 20 ° C. Thereby, it has been confirmed that by adopting the configuration of the heater 100 of the present invention, it is possible to reduce the uneven temperature distribution on the main surface of the ceramic structure 1. As a result, it was found that when the heater 100 was repeatedly used, the possibility of cracks occurring on the main surface of the ceramic structure 1 could be reduced.
　また、さらに他の評価試験として、ガスの導入口が設けられた試験用の筺体の内部に試料２～４および比較例１をセットした。そして、筺体の内部にガスを流入し続けるとともに、試料２～４のヒータ１００および比較例１のヒータに電流を流してからガスが着火するまでの時間と、電流を流すことをやめてから消火するまでの時間を調べた。ガスとしては、ディーゼル燃料を気化させたものを使用した。その結果、試料２および試料３のヒータ１００では着火までの時間が４０秒以内であった。これに対し、比較例１のヒータでは着火までの時間が６０秒かかった。この結果から、試料２および試料３のヒータ１００は比較例１のヒータに比べて、着火するまでの時間が２０秒短くなり、着火性が良くなっていることが分かる。 As still another evaluation test, Samples 2 to 4 and Comparative Example 1 were set inside a test case provided with a gas inlet. The gas continues to flow into the housing, and the time from when the current is supplied to the heaters 100 of the samples 2 to 4 and the heater of the comparative example 1 until the gas is ignited, and after the current is stopped, is extinguished. Investigate the time until. As gas, the gasified diesel fuel was used. As a result, in the heaters 100 of Sample 2 and Sample 3, the time until ignition was within 40 seconds. In contrast, the heater of Comparative Example 1 took 60 seconds to ignite. From this result, it can be seen that the heaters 100 of Sample 2 and Sample 3 have a shorter ignition time of 20 seconds than the heater of Comparative Example 1, and the ignitability is improved.
　これは、試料２のヒータが内側の内壁面が外側の内壁面よりも緩やかに傾斜している溝部４を有していることによって、溝部４の外周側から入り込んだガスの流れを内壁面の近傍で穏やかにすることにより、ガスが溝部４に留まりやすくなることで、着火性が向上したものと考えられる。さらに、試料３に関しては、溝部４を囲う凸部５を有することによって、ガスを溝部４にさらに留まりやすくすることができたことによって、着火性が向上したものと考えられる。 This is because the heater of the sample 2 has the groove portion 4 in which the inner wall surface on the inner side is inclined more gently than the inner wall surface on the outer side, whereby the flow of gas entering from the outer peripheral side of the groove portion 4 is reduced. It is considered that the ignitability is improved because the gas tends to stay in the groove portion 4 by being gentle in the vicinity. Further, regarding the sample 3, it is considered that the ignitability is improved by having the convex portion 5 surrounding the groove portion 4 so that the gas can more easily stay in the groove portion 4.
　さらに、比較例１のヒータと試料４のヒータ１００とに関して、発熱終了後の消火にかかる時間を比較したところ、試料４のヒータに関しては電流を流すことをやめてから消火するまでの時間が７０秒程度であったのに対して、比較例１のヒータでは消火するまでの時間が１００秒程度であった。これは、凸部５の形状を曲線状にすることで、ヒータ１００の周囲にガスを流したときに、ガスが凸部５の内側に流れ込みやすくなった結果、凸部５の内側でガスを効率よく燃焼させることができたためと考えられる。 Furthermore, when the time required for extinguishing after the end of heat generation was compared for the heater of Comparative Example 1 and the heater 100 of Sample 4, the time required to extinguish the current for the heater of Sample 4 from 70 seconds is 70 seconds. On the other hand, with the heater of Comparative Example 1, the time to extinguish was about 100 seconds. This is because when the gas flows around the heater 100 by making the shape of the convex portion 5 curved, the gas easily flows into the convex portion 5. It is thought that it was able to burn efficiently.
１：セラミック構造体
１０：最高発熱部
２：発熱抵抗体
２１：折返し部
２２：直線部
３：給電線
４：溝部
５：凸部
６：凹部
７：リード端子
１００：ヒータ 1: Ceramic structure 10: Maximum heat generating part 2: Heat generating resistor 21: Folding part 22: Straight line part 3: Feed line 4: Groove part 5: Convex part 6: Concave part 7: Lead terminal 100: Heater

Claims (7)

  1. 　セラミック構造体と、該セラミック構造体に埋設された折返し部を有する発熱抵抗体とを具備し、前記セラミック構造体は、前記折返し部が面している表面に前記折返し部を囲む溝部を有するヒータ。 A heater having a ceramic structure and a heating resistor having a folded portion embedded in the ceramic structure, the ceramic structure having a groove portion surrounding the folded portion on a surface facing the folded portion .
  2. 　前記溝部は、円環状である請求項１に記載のヒータ。 The heater according to claim 1, wherein the groove is annular.
  3. 　前記セラミック構造体の表面に垂直な断面で見たときに、前記溝部の形状が曲線状である請求項１または請求項２に記載のヒータ。 The heater according to claim 1 or 2, wherein the groove has a curved shape when viewed in a cross section perpendicular to the surface of the ceramic structure.
  4. 　前記溝部の壁面は、内周側の傾斜が外周側の傾斜に比べて緩やかである請求項１乃至請求項３のいずれかに記載のヒータ。 The heater according to any one of claims 1 to 3, wherein the wall surface of the groove portion has a gentler inclination on the inner peripheral side than that on the outer peripheral side.
  5. 　前記溝部の外周に沿って連続した凸部が形成されている請求項１乃至請求項４のいずれかに記載のヒータ。 The heater according to any one of claims 1 to 4, wherein a continuous convex portion is formed along an outer periphery of the groove portion.
  6. 　前記セラミック構造体の表面に垂直な断面で見たときに、前記凸部の形状が曲線状である請求項５に記載のヒータ。 The heater according to claim 5, wherein the convex portion has a curved shape when viewed in a cross section perpendicular to the surface of the ceramic structure.
  7. 　セラミック構造体と、該セラミック構造体に埋設された折返し部を有する発熱抵抗体とを具備し、前記セラミック構造体は、前記折返し部が面している表面のうち前記折返し部に重なる領域に凹部を有するヒータ。 A ceramic structure and a heating resistor having a folded portion embedded in the ceramic structure, wherein the ceramic structure is recessed in a region of the surface facing the folded portion that overlaps the folded portion. Having a heater.
PCT/JP2013/085105 2012-12-27 2013-12-27 Heater WO2014104293A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2014554592A JP5960845B2 (en) 2012-12-27 2013-12-27 heater
EP13869090.4A EP2941090B1 (en) 2012-12-27 2013-12-27 Heater

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Citations (5)

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Publication number Priority date Publication date Assignee Title
JPS54150727U (en) * 1978-04-14 1979-10-19
JPH0129427Y2 (en) * 1985-12-27 1989-09-07
JPH03183942A (en) * 1989-12-14 1991-08-09 Ngk Spark Plug Co Ltd Heater structure of sensor
JP2006040882A (en) 2004-06-25 2006-02-09 Ngk Spark Plug Co Ltd Manufacturing method of ceramic heater, ceramic heater manufactured by this method, and glow plug equipped with ceramic heater
JP2009231161A (en) * 2008-03-25 2009-10-08 Ngk Spark Plug Co Ltd Ceramic heater and glow plug

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2022282C3 (en) * 1970-05-06 1980-05-29 Villamosipari Kutato Intezet, Budapest Process for the manufacture of an electrical heating element
EP0635993B1 (en) * 1993-07-20 2000-05-17 TDK Corporation Ceramic heater
EP1612486B1 (en) * 2004-06-29 2015-05-20 Ngk Spark Plug Co., Ltd Glow plug
FR2898960B1 (en) * 2006-03-21 2008-05-30 Renault Sas PREHEATING PLUG FOR COMBUSTION ENGINE

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54150727U (en) * 1978-04-14 1979-10-19
JPH0129427Y2 (en) * 1985-12-27 1989-09-07
JPH03183942A (en) * 1989-12-14 1991-08-09 Ngk Spark Plug Co Ltd Heater structure of sensor
JP2006040882A (en) 2004-06-25 2006-02-09 Ngk Spark Plug Co Ltd Manufacturing method of ceramic heater, ceramic heater manufactured by this method, and glow plug equipped with ceramic heater
JP2009231161A (en) * 2008-03-25 2009-10-08 Ngk Spark Plug Co Ltd Ceramic heater and glow plug

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JP5960845B2 (en) 2016-08-02
EP2941090A4 (en) 2016-08-17
JPWO2014104293A1 (en) 2017-01-19
EP2941090A1 (en) 2015-11-04
EP2941090B1 (en) 2018-02-21

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