WO2015064598A1 - Heater and glow plug - Google Patents

Heater and glow plug Download PDF

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Publication number
WO2015064598A1
WO2015064598A1 PCT/JP2014/078675 JP2014078675W WO2015064598A1 WO 2015064598 A1 WO2015064598 A1 WO 2015064598A1 JP 2014078675 W JP2014078675 W JP 2014078675W WO 2015064598 A1 WO2015064598 A1 WO 2015064598A1
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WO
WIPO (PCT)
Prior art keywords
ceramic body
metal cap
slit
heater
conductor layer
Prior art date
Application number
PCT/JP2014/078675
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French (fr)
Japanese (ja)
Inventor
幸範 福永
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 EP14859213.2A priority Critical patent/EP3064834B1/en
Priority to JP2015545249A priority patent/JP6075810B2/en
Publication of WO2015064598A1 publication Critical patent/WO2015064598A1/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
    • 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, for example, a heater used in various sensors or measuring devices such as a combustion-type in-vehicle heating device, an oil fan heater, a glow plug of an automobile engine, an oxygen sensor, and a glow plug using the heater.
  • a heater used in various sensors or measuring devices such as a combustion-type in-vehicle heating device, an oil fan heater, a glow plug of an automobile engine, an oxygen sensor, and a glow plug using the heater.
  • Patent Document 1 Japanese Utility Model Publication No. 63-80456 (hereinafter, referred to as Patent Document 1) is used as a heater used in various sensors or measuring devices such as a combustion-type in-vehicle heating device, an oil fan heater, a glow plug of an automobile engine, and an oxygen sensor.
  • the heater disclosed in is known.
  • the heater disclosed in Patent Document 1 includes a ceramic body in which a heating resistor is embedded, and a metal cap provided so as to cover one end of the ceramic body.
  • the metal cap is electrically connected to the heating resistor, and power can be supplied to the heating resistor by connecting a lead terminal to the metal cap. In this way, the heater can generate heat.
  • the present invention has been made in view of such problems, and an object of the present invention is to provide a heater that can reduce the thermal stress generated between the ceramic body and the metal cap.
  • the heater according to one aspect of the present invention includes a rod-shaped ceramic body, a heating resistor embedded in the ceramic body, and provided at least on one surface of the ceramic body and electrically connected to the heating resistor.
  • a conductive layer, and a metal cap for external connection provided so as to cover the one end of the ceramic body together with at least a part of the conductive layer, and the metal cap is formed on a part of the outer periphery from the outside to the inside. It has a slit to go.
  • FIG. 2 is a perspective view of one end of a ceramic body and a conductor layer of the heater shown in FIG. 1. It is a perspective view of the metal cap of the heater shown in FIG. It is the perspective view which expanded the vicinity of the metal cap among the heaters shown in FIG. It is sectional drawing to which the vicinity of the metal cap was expanded among the heaters shown in FIG.
  • FIG. 1 is a sectional view showing a heater 10 according to an embodiment of the present invention.
  • the heater 10 includes a ceramic body 1, a heating resistor 2 embedded in the ceramic body 1, and a metal cap 4 that covers one end side of the ceramic body 1.
  • a conductor layer 3 is further provided on one end side of the ceramic body 1 as shown in FIG. 2.
  • the region where the conductor layer 3 is provided is indicated by hatching.
  • the heating resistor 2 and the conductor layer 3 are electrically connected via the lead-out part 22.
  • the ceramic body 1 is a member formed in a rod shape, for example.
  • the bar shape means a shape that is long in one direction. Therefore, for example, even if it is a plate shape that is long in one direction, it can be regarded as a rod shape.
  • the ceramic body 1 is provided with a tapered portion 11 on one end side.
  • ceramics having electrical insulation properties such as oxide ceramics, nitride ceramics, or carbide ceramics are used. Specifically, alumina ceramics, silicon nitride ceramics, aluminum nitride ceramics, silicon carbide ceramics, or the like can be used.
  • the ceramic body 1 is preferably made of silicon nitride ceramics. Silicon nitride ceramics are excellent in that silicon nitride as a main component has high strength, high toughness, high insulation and high heat resistance.
  • the ceramic body 1 made of silicon nitride ceramic is, for example, 5 to 15% by mass of a rare earth element such as Y 2 O 3 , Yb 2 O 3 or Er 2 O 3 as a sintering aid with respect to silicon nitride as a main component.
  • Element oxide, 0.5-5% by mass of Al 2 O 3 , and SiO 2 are mixed so that the amount of SiO 2 contained in the sintered body is 1.5-5% by mass, and formed into a predetermined shape Then, it can be obtained by hot press firing at 1650 to 1780 ° C.
  • the length is set to 20 to 50 mm, for example, and the diameter of the ceramic body 1 is set to 2.5 to 5 mm, for example.
  • the length of the ceramic body 1 is about 20 to 50 mm and the diameter of the ceramic body 1 is about 3 mm
  • the length of the tapered portion 11 is 0.1 to 3 mm
  • the diameter of the end face of the tapered portion 11 is It can be set to 1 to 2.9 mm.
  • the ceramic body 1 is made of silicon nitride ceramics and the heating resistor 2 is made of molybdenum (Mo) or tungsten (W), the ceramic body 1 includes MoSi 2 and WSi. It is preferable to mix and disperse 2 etc. Thereby, the thermal expansion coefficient of the silicon nitride ceramics which is a base material can be brought close to the thermal expansion coefficient of the heating resistor 2, and the durability of the heater 10 can be improved.
  • the heating resistor 2 is a resistor for generating heat and generates heat when a current flows.
  • the heating resistor 2 is embedded in the ceramic body 1.
  • the heating resistor 2 includes a heating part 21 that is a part that mainly generates heat, and a lead-out part 22 connected to the heating part 21.
  • the heat generating portion 21 is provided on the other end side of the ceramic body 1.
  • the heat generating portion 21 has a folded shape, and each end portion is connected to the lead-out portion 22.
  • the heat generating portion 21 is a portion that generates the most heat near the center of the folded portion in the folded shape.
  • the length from the front end of the heat generating portion 21 to the rear end of the heat generating resistor 2 in the length direction of the ceramic body 1 is set to 2 to 10 mm, for example.
  • the lead-out part 22 is a member for electrically connecting the heat generating part 21 and an external power source, and one end is drawn out to the surface of the ceramic body 1 and the other end is connected to the heat generating part 21. Yes.
  • the lead-out part 22 is separately connected to both ends of the heat generating part 21.
  • One lead-out portion 22 is drawn out to the end face on one end side of the ceramic body 1. In FIG. 2, a portion where the lead-out portion 22 is drawn out on the end face on one end side of the ceramic body 1 is indicated by a broken line.
  • the other lead-out part 22 is drawn out to the outer peripheral surface of the region on one end side of the ceramic body 1.
  • the heating resistor 2 may be composed mainly of carbides such as W, Mo or titanium (Ti), nitrides or silicides. Further, the heating resistor 2 may contain the same material as the ceramic body 1 in order to bring the coefficient of thermal expansion close to that of the ceramic body 1.
  • the heat generating portion 21 has a high resistance value, and generates heat most in the vicinity of the turning point.
  • the lead-out portion 22 generates a resistance value per unit length by reducing the content of the forming material of the ceramic body 1 less than that of the heat generating portion 21 or increasing the cross-sectional area of the heat generating portion 21. It is lower than the part 21.
  • the conductor layer 3 is a member for electrically connecting the heating resistor 2 and an external electrode.
  • the conductor layer 3 is provided on one end side of the ceramic body 1. More specifically, the conductor layer 3 is provided on the end surface of the ceramic body 1 and a part of the outer peripheral surface of the tapered portion 11.
  • the conductor layer 3 is electrically connected to the heating resistor 2 via the lead-out portion 22.
  • the conductor layer 3 includes a metallized layer and a plating layer laminated on the metallized layer.
  • the metallized layer for example, a metallized layer containing silver, copper and titanium or a metallized layer containing gold, nickel and palladium (Pd) can be used.
  • the plating layer for example, nickel boron plating, gold plating or nickel plating can be used.
  • the thickness of the metallized layer can be set to about 20 to 40 ⁇ m, for example. Moreover, it is preferable that the thickness of a plating layer is 1 micrometer or more, for example.
  • the metal cap 4 is a metal member having a bottom portion 41 and side portions 42.
  • a metal material such as stainless steel or iron (Fe) -nickel (Ni) -cobalt (Co) alloy can be used.
  • iron (Fe) -nickel (Ni) -cobalt (Co) alloy it is preferable to use an iron (Fe) -nickel (Ni) -cobalt (Co) alloy.
  • the metal cap 4 is a member for firmly connecting the conductor layer 3 and an external electrode.
  • the metal cap 4 is provided so as to cover one end side of the ceramic body 1 and at least a part of the conductor layer 3, and is electrically connected to the conductor layer 3.
  • the metal cap 4 has a shape corresponding to the taper of the ceramic body 1.
  • the bottom 41 is a plate having a substantially circular diameter.
  • the side portion 42 has a substantially annular shape when viewed in a cross section perpendicular to the axial length direction of the ceramic body 1, and has a shape that widens as the distance from the bottom portion 41 increases.
  • the metal cap 4 is attached to the ceramic body 1 such that the bottom portion 41 faces one end of the ceramic body 1 and the side portion 42 covers a part of the tapered portion 11.
  • the metal cap 4 has a slit 43 that extends from the outer side, that is, the edge, to the inner side, that is, toward the center, on a part of the outer periphery of the metal cap 4. More specifically, a slit 43 is provided from the lower end of the side portion 42 toward the center of the bottom portion 41.
  • a slit 43 is provided from the lower end of the side portion 42 toward the center of the bottom portion 41.
  • the inclination angle ⁇ of the inner peripheral surface of the side portion 42 is larger than the inclination angle ⁇ of the tapered portion 11.
  • the inclination angle ⁇ indicates how much the inner peripheral surface of the side portion 42 is inclined with respect to the plane including the inner surface of the bottom portion 41.
  • the inclination angle ⁇ indicates how much the outer peripheral surface of the tapered portion 11 is inclined with respect to the surface perpendicular to the axial direction of the ceramic body 1.
  • the inclination angle ⁇ is larger than the inclination angle ⁇ , when the metal cap 4 is attached to the taper portion 11, the lower surface of the side portion 42 of the metal cap 4 is in contact with the taper portion 11, and the bottom 41 of the metal cap 4 A gap can be formed between the inner side surface and the portion of the conductor layer 3 provided on the end surface of the tapered portion 11. And as shown in FIG. 5, the metal cap 4 and the conductor layer 3 can be firmly joined by interposing the brazing material 7 in this gap.
  • the inclination angle ⁇ of the inner peripheral surface of the side portion 42 can be set to 40 to 80 °, for example. Further, the inclination angle ⁇ of the tapered portion 11 can be set to 45 to 75 °, for example.
  • the brazing material 7 is omitted for the sake of easy viewing.
  • the slit 43 of the metal cap 4 reaches the center of the metal cap 4.
  • the slit 43 is formed from the lower end of the side portion 42 of the metal cap 4 to the central portion of the bottom portion 41.
  • the tip of the slit 43 is processed into a round hole at the center.
  • Such a shape can also be regarded as one slit 43.
  • the slit 43 having a constant width may reach the center of the bottom 41, or the width of the slit 43 may change midway.
  • the inner diameter of the bottom 41 is set to about 1.5 to 2 mm and the thickness of the bottom 41 is set to about 0.1 to 0.5 mm. it can. Further, the inner diameter of the lower end of the side portion 42 is set to about 1.5 to 2.5 mm, the thickness of the side portion 42 is set to about 0.1 to 0.5 mm, and the height of the side portion 42 is set to 1 to 1.2 mm. Can be set.
  • the length of the slit 43 can be set to 1 to 2 mm.
  • the heater 10 further includes a lead terminal 5 whose end is connected to the conductor layer 3.
  • the lead terminal 5 is a member for electrically connecting the metal cap 4 and the conductor layer 3 to an external electrode.
  • the lead terminal 5 is made of a metal material such as nickel or stainless steel.
  • the lead terminal 5 is a linear member, and an end thereof is located inside the slit 43 of the metal cap 4 and is joined to the metal cap 4. Thereby, compared with the case where the outer surface of the bottom part 41 of the metal cap 4 and the lead terminal 5 are joined, the metal cap 4 and the lead terminal 5 can be joined firmly.
  • the brazing material 7 described above extends to the inside of the portion of the slit 43 located at the bottom 41, and the brazing material 7 surrounds the lead terminal 5.
  • the brazing material 7 spreads not only inside the portion of the slit 43 located at the bottom 41 but also outside the bottom 41 and spreads outside the bottom 41. This portion surrounds the end of the lead terminal 5. Thereby, the metal cap 4 and the lead terminal 5 can be joined more firmly.
  • the width of the tip portion of the slit 43 is larger than the width of the portion of the slit 43 from the outside toward the inside.
  • the tip of the slit 43 is circular when viewed from above at the center of the bottom 41 of the metal cap 4, and the diameter (width) of the tip of the slit 43 is from the outside of the slit 43. It is larger than the width of the part going inward.
  • the diameter of the lead terminal 5 may be larger than the width of the portion from the outside toward the inside of the slit 43 and smaller than the diameter (width) of the tip portion of the slit 43. Thereby, the possibility that the lead terminal 5 is shifted to the portion from the outside toward the inside of the slit 43 can be further reduced.
  • tip part of the slit 43 is circular shape, it is not restricted to this. Specifically, the distal end portion of the slit 43 may be a polygonal shape such as a square shape. Further, the tip portion of the slit 43 may be oval or oval. In addition, when the shape of the front-end
  • the brazing material 7 may spread out in the portion of the slit 43 located at the bottom 41 and the brazing material 7 may not be spread out in the portion of the slit 43 located at the side 42. Thereby, the thermal stress generated between the metal cap 4 and the ceramic body 1 can be reduced while firmly bonding the metal cap 4 and the lead terminal 5.
  • the brazing material 7 may be spread not only on the portion of the conductor layer 3 provided on the end surface of the ceramic body 1 but also on a portion provided on a part of the outer peripheral surface of the tapered portion 11. And the part provided in a part of outer peripheral surface of the taper part 11 among the conductor layers 3 and the side part 42 of the metal cap 4 may be joined. Thereby, the metal cap 4 and the lead terminal 5 can be joined more firmly.
  • the metal cap 4 has a bottom portion 41 and a side portion 42, and the conductor layer 3 is located closer to the bottom 41 side than the end portion on the opening side of the side portion 42 of the metal cap 4 in the surface of the ceramic body 1. . More specifically, the end portion of the side portion 42 of the metal cap 4 that is located on the opposite side of the bottom portion 41 is in contact with the outer peripheral surface of the tapered portion 11, and the portion of the outer peripheral surface of the tapered portion 11 that is in contact with the side portion 42. Also, the conductor layer 3 is provided on the end face side of the ceramic body 1. In other words, a configuration in which the conductor layer 3 is not provided on a portion of the outer peripheral surface of the tapered portion 11 that is in contact with the side portion 42 may be adopted. Thereby, when the conductor layer 3 and the metal cap 4 are joined by the brazing material 7, the brazing material 7 can be easily stored between the conductor layer 3 and the metal cap 4.
  • the lead-out portion 22 of the heating resistor 2 is drawn to the end face of one end of the ceramic body 1.
  • the portion from which the lead-out portion 22 is drawn overlaps the slit 43, and the lead terminal 5 is located inside the slit 43. Further, the lead terminal 5 is positioned so as to overlap the portion from which the lead-out portion 22 is drawn.
  • the glow plug 100 of the present embodiment includes the above-described heater 10 and a cylindrical metal member 6 attached to the tapered portion 11 side of the heater 10.
  • the metal member 6 is a member for holding the ceramic body 1.
  • the metal member 6 is a cylindrical member and is provided so as to surround one end side of the ceramic body 1. In other words, the ceramic body 1 is inserted inside the metal member 6.
  • the metal member 6 is electrically connected to the other lead-out portion 22 drawn to one end side of the ceramic body 1.
  • the metal member 6 is made of, for example, stainless steel or iron (Fe) -nickel (Ni) -cobalt (Co) alloy.
  • the metal member 6 and the ceramic body 1 are joined by a brazing material (not shown).
  • the brazing material is provided so as to surround the end of the ceramic body 1.
  • the brazing material is provided in layers on the entire circumference of the end of the ceramic body 1.
  • the glow plug 100 of the present embodiment includes the heater 10 in which the thermal stress generated between the metal cap 4 and the ceramic body 1 is reduced, so that the long-term reliability of the heater 10 is improved. As a result, the long-term reliability of the glow plug 100 is improved.

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

Abstract

This heater is provided with: a rod-shaped ceramic body; a heating resistor embedded in the ceramic body; a conductor layer electrically connected to the heating resistor; and a metal cap that is for external connection and is provided so as to cover one end of the ceramic body together with at least a portion of the conductor layer. The metal cap has, in a portion of the outer periphery thereof, a slit that extends toward the inside from the outside.

Description

ヒータおよびグロープラグHeater and glow plug
　本発明は、例えば、燃焼式車載暖房装置、石油ファンヒータ、自動車エンジンのグロープラグ、酸素センサ等の各種センサまたは測定機器に利用されるヒータおよびこれを用いたグロープラグに関するものである。 The present invention relates to, for example, a heater used in various sensors or measuring devices such as a combustion-type in-vehicle heating device, an oil fan heater, a glow plug of an automobile engine, an oxygen sensor, and a glow plug using the heater.
　燃焼式車載暖房装置、石油ファンヒータ、自動車エンジンのグロープラグ、酸素センサ等の各種センサまたは測定機器に利用されるヒータとして、例えば、実開昭６３－８０４５６号公報（以下、特許文献１という）に開示されたヒータが知られている。特許文献１に開示されたヒータは、内部に発熱抵抗体が埋設されたセラミック体と、セラミック体の一端を覆うように設けられた金属キャップとを備えている。金属キャップは発熱抵抗体に電気的に接続されており、この金属キャップにリード端子を接続することによって、発熱抵抗体に電力を供給することができる。このようにして、ヒータを発熱させることができる。 For example, Japanese Utility Model Publication No. 63-80456 (hereinafter, referred to as Patent Document 1) is used as a heater used in various sensors or measuring devices such as a combustion-type in-vehicle heating device, an oil fan heater, a glow plug of an automobile engine, and an oxygen sensor. The heater disclosed in is known. The heater disclosed in Patent Document 1 includes a ceramic body in which a heating resistor is embedded, and a metal cap provided so as to cover one end of the ceramic body. The metal cap is electrically connected to the heating resistor, and power can be supplied to the heating resistor by connecting a lead terminal to the metal cap. In this way, the heater can generate heat.
　しかしながら、特許文献１に開示されたヒータにおいては、異なる材料から成るセラミック体と金属キャップとの間に熱応力が生じる場合があった。そのため、ヒートサイクル下におけるヒータの長期信頼性を向上させることが困難であるという問題点があった。 However, in the heater disclosed in Patent Document 1, thermal stress may occur between the ceramic body made of different materials and the metal cap. Therefore, there is a problem that it is difficult to improve the long-term reliability of the heater under a heat cycle.
　本発明はかかる問題点に鑑みてなされたものであり、その目的は、セラミック体と金属キャップとの間に生じる熱応力を低減することができるヒータを提供することにある。 The present invention has been made in view of such problems, and an object of the present invention is to provide a heater that can reduce the thermal stress generated between the ceramic body and the metal cap.
　本発明の一態様のヒータは、棒状のセラミック体と、該セラミック体に埋設された発熱抵抗体と、少なくとも前記セラミック体の一端の表面に設けられて前記発熱抵抗体に電気的に接続された導体層と、前記セラミック体の前記一端を前記導体層の少なくとも一部とともに覆うように設けられた外部接続用の金属キャップとを備えており、該金属キャップが外周の一部に外側から内側に向かうスリットを有していることを特徴とする。 The heater according to one aspect of the present invention includes a rod-shaped ceramic body, a heating resistor embedded in the ceramic body, and provided at least on one surface of the ceramic body and electrically connected to the heating resistor. A conductive layer, and a metal cap for external connection provided so as to cover the one end of the ceramic body together with at least a part of the conductive layer, and the metal cap is formed on a part of the outer periphery from the outside to the inside. It has a slit to go.
本発明のヒータおよびグロープラグの一実施形態の断面図である。It is sectional drawing of one Embodiment of the heater and glow plug of this invention. 図１に示すヒータのセラミック体の一端および導体層の斜視図である。FIG. 2 is a perspective view of one end of a ceramic body and a conductor layer of the heater shown in FIG. 1. 図１に示すヒータの金属キャップの斜視図である。It is a perspective view of the metal cap of the heater shown in FIG. 図１に示すヒータのうち金属キャップの近傍を拡大した斜視図である。It is the perspective view which expanded the vicinity of the metal cap among the heaters shown in FIG. 図１に示すヒータのうち金属キャップの近傍を拡大した断面図である。It is sectional drawing to which the vicinity of the metal cap was expanded among the heaters shown in FIG.
　以下、本発明の一実施形態に係るヒータについて、図面を参照しながら説明する。図１は本発明の一実施形態に係るヒータ１０を示す断面図である。図１に示すように、ヒータ１０は、セラミック体１と、セラミック体１に埋設された発熱抵抗体２と、セラミック体１の一端側を覆う金属キャップ４とを備えている。また、図１には示していないが、図２に示すように、セラミック体１の一端側にはさらに導体層３が設けられている。なお、図２においては、導体層３が設けられた領域をハッチングで示している。発熱抵抗体２と導体層３とは、導出部２２を介して電気的に接続されている。 Hereinafter, a heater according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a heater 10 according to an embodiment of the present invention. As shown in FIG. 1, the heater 10 includes a ceramic body 1, a heating resistor 2 embedded in the ceramic body 1, and a metal cap 4 that covers one end side of the ceramic body 1. Although not shown in FIG. 1, a conductor layer 3 is further provided on one end side of the ceramic body 1 as shown in FIG. 2. In FIG. 2, the region where the conductor layer 3 is provided is indicated by hatching. The heating resistor 2 and the conductor layer 3 are electrically connected via the lead-out part 22.
　セラミック体１は、例えば、棒状に形成された部材である。なお、ここでいう棒状とは、一方向に長い形状であることを意味している。そのため、例えば、一方向に長い板状のような形状であったとしても棒状として見なすことができる。セラミック体１には、一端側にテーパー部１１が設けられている。セラミック体１としては、例えば、酸化物セラミックス、窒化物セラミックスまたは炭化物セラミックス等の電気的な絶縁性を有するセラミックスが用いられる。具体的には、アルミナ質セラミックス、窒化珪素質セラミックス、窒化アルミニウム質セラミックスまたは炭化珪素質セラミックス等を用いることができる。特に、セラミック体１が窒化珪素質セラミックスから成ることが好適である。窒化珪素質セラミックスは、主成分である窒化珪素が高強度、高靱性、高絶縁性および耐高熱性を有している点で優れている。 The ceramic body 1 is a member formed in a rod shape, for example. Here, the bar shape means a shape that is long in one direction. Therefore, for example, even if it is a plate shape that is long in one direction, it can be regarded as a rod shape. The ceramic body 1 is provided with a tapered portion 11 on one end side. As the ceramic body 1, for example, ceramics having electrical insulation properties such as oxide ceramics, nitride ceramics, or carbide ceramics are used. Specifically, alumina ceramics, silicon nitride ceramics, aluminum nitride ceramics, silicon carbide ceramics, or the like can be used. In particular, the ceramic body 1 is preferably made of silicon nitride ceramics. Silicon nitride ceramics are excellent in that silicon nitride as a main component has high strength, high toughness, high insulation and high heat resistance.
　窒化珪素質セラミックスから成るセラミック体１は、例えば、主成分の窒化珪素に対して、焼結助剤として５～１５質量％のＹ２Ｏ３、Ｙｂ２Ｏ３またはＥｒ２Ｏ３等の希土類元素酸化物、０．５～５質量％のＡｌ２Ｏ３、さらに焼結体に含まれるＳｉＯ２量が１．５～５質量％となるようにＳｉＯ２を混合し、所定の形状に成形し、その後、１６５０～１７８０℃でホットプレス焼成することによって得ることができる。棒状のセラミック体１である場合、その長さは、例えば２０～５０ｍｍに設定され、セラミック体１の直径は、例えば２．５～５ｍｍに設定される。セラミック体１の長さが２０～５０ｍｍ程度であって、セラミック体１の直径が３ｍｍ程度の場合には、テーパー部１１の長さは０．１～３ｍｍに、テーパー部１１の端面の直径は１～２．９ｍｍに設定できる。 The ceramic body 1 made of silicon nitride ceramic is, for example, 5 to 15% by mass of a rare earth element such as Y 2 O 3 , Yb 2 O 3 or Er 2 O 3 as a sintering aid with respect to silicon nitride as a main component. Element oxide, 0.5-5% by mass of Al 2 O 3 , and SiO 2 are mixed so that the amount of SiO 2 contained in the sintered body is 1.5-5% by mass, and formed into a predetermined shape Then, it can be obtained by hot press firing at 1650 to 1780 ° C. In the case of the rod-shaped ceramic body 1, the length is set to 20 to 50 mm, for example, and the diameter of the ceramic body 1 is set to 2.5 to 5 mm, for example. When the length of the ceramic body 1 is about 20 to 50 mm and the diameter of the ceramic body 1 is about 3 mm, the length of the tapered portion 11 is 0.1 to 3 mm, and the diameter of the end face of the tapered portion 11 is It can be set to 1 to 2.9 mm.
　なお、セラミック体１として窒化珪素質セラミックスから成るものを用いる場合であって、発熱抵抗体２がモリブデン（Ｍｏ）またはタングステン（Ｗ）から成る場合には、セラミック体１には、ＭｏＳｉ２およびＷＳｉ２等を混合して分散させることが好ましい。これにより、母材である窒化珪素質セラミックスの熱膨張率を発熱抵抗体２の熱膨張率に近付けることができ、ヒータ１０の耐久性を向上させることができる。 When the ceramic body 1 is made of silicon nitride ceramics and the heating resistor 2 is made of molybdenum (Mo) or tungsten (W), the ceramic body 1 includes MoSi 2 and WSi. It is preferable to mix and disperse 2 etc. Thereby, the thermal expansion coefficient of the silicon nitride ceramics which is a base material can be brought close to the thermal expansion coefficient of the heating resistor 2, and the durability of the heater 10 can be improved.
　発熱抵抗体２は、発熱するための抵抗体であって、電流が流れることによって発熱する。発熱抵抗体２は、セラミック体１に埋設されている。発熱抵抗体２は、主に発熱する部分である発熱部２１と、発熱部２１に接続された導出部２２とから成る。発熱抵抗体２とのうち、発熱部２１はセラミック体１の他端側に設けられている。発熱部２１は、折返し形状を有しており、それぞれの端部が導出部２２に接続されている。発熱部２１は、折返し形状における折返し部の中央付近が最も発熱する部分となっている。セラミック体１の長さ方向における発熱部２１の先端から発熱抵抗体２の後端までの長さは、例えば２～１０ｍｍに設定される。 The heating resistor 2 is a resistor for generating heat and generates heat when a current flows. The heating resistor 2 is embedded in the ceramic body 1. The heating resistor 2 includes a heating part 21 that is a part that mainly generates heat, and a lead-out part 22 connected to the heating part 21. Of the heat generating resistor 2, the heat generating portion 21 is provided on the other end side of the ceramic body 1. The heat generating portion 21 has a folded shape, and each end portion is connected to the lead-out portion 22. The heat generating portion 21 is a portion that generates the most heat near the center of the folded portion in the folded shape. The length from the front end of the heat generating portion 21 to the rear end of the heat generating resistor 2 in the length direction of the ceramic body 1 is set to 2 to 10 mm, for example.
　導出部２２は、発熱部２１と外部の電源とを電気的に接続するための部材であって、一端がセラミック体１の表面に引き出されているとともに、他端が発熱部２１に接続されている。導出部２２は、発熱部２１の両端に別々に接続されている。一方の導出部２２は、セラミック体１の一端側の端面に引き出されている。図２においては、セラミック体１の一端側の端面において導出部２２が引き出されている箇所を破線で示している。また、他方の導出部２２は、セラミック体１の一端側の領域の外周面に引き出されている。 The lead-out part 22 is a member for electrically connecting the heat generating part 21 and an external power source, and one end is drawn out to the surface of the ceramic body 1 and the other end is connected to the heat generating part 21. Yes. The lead-out part 22 is separately connected to both ends of the heat generating part 21. One lead-out portion 22 is drawn out to the end face on one end side of the ceramic body 1. In FIG. 2, a portion where the lead-out portion 22 is drawn out on the end face on one end side of the ceramic body 1 is indicated by a broken line. The other lead-out part 22 is drawn out to the outer peripheral surface of the region on one end side of the ceramic body 1.
　発熱抵抗体２には、Ｗ、Ｍｏまたはチタン（Ｔｉ）等の炭化物、窒化物または珪化物等を主成分とするものを使用することができる。さらに、発熱抵抗体２は、熱膨張率をセラミック体１の熱膨張率に近付けるために、セラミック体１と同じ材料を含んでいてもよい。発熱部２１は抵抗値が高く設定されていて、特に折返し点付近で最も発熱するようになっている。一方、導出部２２は、セラミック体１の形成材料の含有量を発熱部２１よりも少なくしたり、発熱部２１よりも断面積を大きくしたりすることによって、単位長さ当たりの抵抗値が発熱部２１よりも低くなっている。 The heating resistor 2 may be composed mainly of carbides such as W, Mo or titanium (Ti), nitrides or silicides. Further, the heating resistor 2 may contain the same material as the ceramic body 1 in order to bring the coefficient of thermal expansion close to that of the ceramic body 1. The heat generating portion 21 has a high resistance value, and generates heat most in the vicinity of the turning point. On the other hand, the lead-out portion 22 generates a resistance value per unit length by reducing the content of the forming material of the ceramic body 1 less than that of the heat generating portion 21 or increasing the cross-sectional area of the heat generating portion 21. It is lower than the part 21.
　導体層３は、発熱抵抗体２と外部の電極とを電気的に接続するための部材である。導体層３は、セラミック体１の一端側に設けられている。より具体的には、導体層３は、セラミック体１の端面およびテーパー部１１の外周面の一部に設けられている。導体層３は、導出部２２を介して発熱抵抗体２に電気的に接続されている。導体層３は、メタライズ層およびメタライズ層に積層されたメッキ層から成る。メタライズ層としては、例えば、銀、銅およびチタンを含むメタライズ層または金、ニッケルおよびパラジウム（Ｐｄ）を含むメタライズ層を用いることができる。メッキ層としては、例えばニッケルボロンメッキ、金メッキまたはニッケルメッキを用いることができる。メタライズ層の厚みは、例えば２０～４０μｍ程度に設定できる。また、メッキ層の厚みは、例えば１μｍ以上であることが好ましい。 The conductor layer 3 is a member for electrically connecting the heating resistor 2 and an external electrode. The conductor layer 3 is provided on one end side of the ceramic body 1. More specifically, the conductor layer 3 is provided on the end surface of the ceramic body 1 and a part of the outer peripheral surface of the tapered portion 11. The conductor layer 3 is electrically connected to the heating resistor 2 via the lead-out portion 22. The conductor layer 3 includes a metallized layer and a plating layer laminated on the metallized layer. As the metallized layer, for example, a metallized layer containing silver, copper and titanium or a metallized layer containing gold, nickel and palladium (Pd) can be used. As the plating layer, for example, nickel boron plating, gold plating or nickel plating can be used. The thickness of the metallized layer can be set to about 20 to 40 μm, for example. Moreover, it is preferable that the thickness of a plating layer is 1 micrometer or more, for example.
　金属キャップ４は、底部４１と側部４２とを有する金属製の部材である。金属キャップ４には、例えばステンレスまたは鉄（Ｆｅ）－ニッケル（Ｎｉ）－コバルト（Ｃｏ）合金等の金属材料を用いることができる。特に、熱膨張の観点から鉄（Ｆｅ）－ニッケル（Ｎｉ）－コバルト（Ｃｏ）合金を用いることが好ましい。金属キャップ４は、導体層３と外部の電極との接続を強固に行なうための部材である。金属キャップ４は、セラミック体１の一端側および導体層３の少なくとも一部を覆うように設けられており、導体層３に電気的に接続されている。金属キャップ４は、セラミック体１のテーパーに対応した形状を有している。具体的には、底部４１は、略円径の板状である。また、側部４２は、セラミック体１の軸長さ方向に垂直な断面で見たときに、側部４２の形状が略円環であるとともに、底部４１から離れるにつれて広がる形状である。金属キャップ４は、底部４１がセラミック体１の一端と面するとともに、側部４２がテーパー部１１の一部を覆うようにしてセラミック体１に取り付けられる。 The metal cap 4 is a metal member having a bottom portion 41 and side portions 42. For the metal cap 4, for example, a metal material such as stainless steel or iron (Fe) -nickel (Ni) -cobalt (Co) alloy can be used. In particular, from the viewpoint of thermal expansion, it is preferable to use an iron (Fe) -nickel (Ni) -cobalt (Co) alloy. The metal cap 4 is a member for firmly connecting the conductor layer 3 and an external electrode. The metal cap 4 is provided so as to cover one end side of the ceramic body 1 and at least a part of the conductor layer 3, and is electrically connected to the conductor layer 3. The metal cap 4 has a shape corresponding to the taper of the ceramic body 1. Specifically, the bottom 41 is a plate having a substantially circular diameter. Further, the side portion 42 has a substantially annular shape when viewed in a cross section perpendicular to the axial length direction of the ceramic body 1, and has a shape that widens as the distance from the bottom portion 41 increases. The metal cap 4 is attached to the ceramic body 1 such that the bottom portion 41 faces one end of the ceramic body 1 and the side portion 42 covers a part of the tapered portion 11.
　さらに、金属キャップ４は、図３および図４に示すように、金属キャップ４の外周の一部に外側すなわち縁から内側すなわち中央部の側に向かうスリット４３を有している。より具体的には、側部４２の下端から底部４１の中心に向かうスリット４３を有している。これにより、金属キャップ４が熱膨張するときに、スリット４３の幅が狭まるように変形することができる。そのため、金属キャップ４の熱膨張量とセラミック体１の熱膨張量との差を小さくすることができる。これにより、金属キャップ４とセラミック体１との間に生じる熱応力を低減することができる。その結果、ヒータ１０の長期信頼性を向上させることができる。 Further, as shown in FIGS. 3 and 4, the metal cap 4 has a slit 43 that extends from the outer side, that is, the edge, to the inner side, that is, toward the center, on a part of the outer periphery of the metal cap 4. More specifically, a slit 43 is provided from the lower end of the side portion 42 toward the center of the bottom portion 41. Thereby, when the metal cap 4 thermally expands, it can deform | transform so that the width | variety of the slit 43 may become narrow. Therefore, the difference between the thermal expansion amount of the metal cap 4 and the thermal expansion amount of the ceramic body 1 can be reduced. Thereby, the thermal stress produced between the metal cap 4 and the ceramic body 1 can be reduced. As a result, the long-term reliability of the heater 10 can be improved.
　さらに、図５に示すように、金属キャップ４は、側部４２の内周面の傾斜角αがテーパー部１１の傾斜角βに比べて大きい。ここでいう、傾斜角αは、底部４１の内側の面を含む平面に対し側部４２の内周面がどれだけ傾斜しているかを示している。また、傾斜角βは、セラミック体１の軸方向に垂直な面に対してテーパー部１１の外周面がどれだけ傾斜しているかを示している。 Further, as shown in FIG. 5, in the metal cap 4, the inclination angle α of the inner peripheral surface of the side portion 42 is larger than the inclination angle β of the tapered portion 11. Here, the inclination angle α indicates how much the inner peripheral surface of the side portion 42 is inclined with respect to the plane including the inner surface of the bottom portion 41. Further, the inclination angle β indicates how much the outer peripheral surface of the tapered portion 11 is inclined with respect to the surface perpendicular to the axial direction of the ceramic body 1.
　傾斜角αが傾斜角βよりも大きいことによって、金属キャップ４をテーパー部１１に取り付けたときに、金属キャップ４の側部４２の下面がテーパー部１１に接するとともに、金属キャップ４の底部４１の内側面と導体層３のうちテーパー部１１の端面に設けられた部分との間に隙間を生じさせることができる。そして、図５に示すように、この隙間にろう材７を介在させることによって、金属キャップ４と導体層３とを強固に接合できる。側部４２の内周面の傾斜角αは、例えば４０～８０°に設定できる。また、テーパー部１１の傾斜角βは、例えば４５～７５°に設定できる。なお、図１および図４では、図面の見やすさを優先してろう材７の図示を省略している。 Since the inclination angle α is larger than the inclination angle β, when the metal cap 4 is attached to the taper portion 11, the lower surface of the side portion 42 of the metal cap 4 is in contact with the taper portion 11, and the bottom 41 of the metal cap 4 A gap can be formed between the inner side surface and the portion of the conductor layer 3 provided on the end surface of the tapered portion 11. And as shown in FIG. 5, the metal cap 4 and the conductor layer 3 can be firmly joined by interposing the brazing material 7 in this gap. The inclination angle α of the inner peripheral surface of the side portion 42 can be set to 40 to 80 °, for example. Further, the inclination angle β of the tapered portion 11 can be set to 45 to 75 °, for example. In FIG. 1 and FIG. 4, the brazing material 7 is omitted for the sake of easy viewing.
　また、金属キャップ４は、スリット４３が金属キャップ４の中心に達している。言い換えると、スリット４３が金属キャップ４の側部４２の下端から底部４１の中央部にまで形成されている。これにより、底部４１における周方向の熱膨張をバランスよく低減できるので、熱膨張後の底部４１の形状が熱膨張前から比べて歪んでしまうことを低減できる。これにより、金属キャップ４に生じる熱応力をさらに低減することができる。 In addition, the slit 43 of the metal cap 4 reaches the center of the metal cap 4. In other words, the slit 43 is formed from the lower end of the side portion 42 of the metal cap 4 to the central portion of the bottom portion 41. Thereby, since the thermal expansion of the circumferential direction in the bottom part 41 can be reduced with sufficient balance, it can reduce that the shape of the bottom part 41 after thermal expansion will be distorted compared with before thermal expansion. Thereby, the thermal stress generated in the metal cap 4 can be further reduced.
　ここで、本実施形態のヒータ１０においては、中心部においてスリット４３の先端部が丸孔状に加工されている。このような形状も１つのスリット４３と見なすことができる。無論、単に幅が一定のスリット４３が底部４１の中心に達していても構わないし、スリット４３の幅が途中で変化していても構わない。 Here, in the heater 10 of the present embodiment, the tip of the slit 43 is processed into a round hole at the center. Such a shape can also be regarded as one slit 43. Of course, the slit 43 having a constant width may reach the center of the bottom 41, or the width of the slit 43 may change midway.
　金属キャップ４の寸法は、セラミック体１の直径が３ｍｍ程度の場合には、例えば、底部４１の内径を１．５～２ｍｍ程度に、底部４１の厚みを０．１～０．５ｍｍ程度に設定できる。また、側部４２のうち下端の内径を１．５～２．５ｍｍ程度に、側部４２の厚みを０．１～０．５ｍｍ程度に、側部４２の高さを１～１．２ｍｍに設定できる。また、スリット４３の長さは１～２ｍｍに設定できる。 When the diameter of the ceramic body 1 is about 3 mm, for example, the inner diameter of the bottom 41 is set to about 1.5 to 2 mm and the thickness of the bottom 41 is set to about 0.1 to 0.5 mm. it can. Further, the inner diameter of the lower end of the side portion 42 is set to about 1.5 to 2.5 mm, the thickness of the side portion 42 is set to about 0.1 to 0.5 mm, and the height of the side portion 42 is set to 1 to 1.2 mm. Can be set. The length of the slit 43 can be set to 1 to 2 mm.
　ヒータ１０は、端部が導体層３に接続されたリード端子５をさらに備えている。リード端子５は、金属キャップ４および導体層３と外部の電極とを電気的に接続するための部材である。リード端子５は、例えばニッケルまたはステンレス等の金属材料から成る。リード端子５は、線状の部材であって、端部が金属キャップ４のスリット４３の内部に位置して金属キャップ４に接合されている。これにより、単に金属キャップ４の底部４１の外側面とリード端子５とを接合する場合と比較して、金属キャップ４とリード端子５とを強固に接合することができる。このとき、前述したろう材７はスリット４３のうち底部４１に位置する部分の内部にまで広がっているとともに、ろう材７がリード端子５を囲んでいる。 The heater 10 further includes a lead terminal 5 whose end is connected to the conductor layer 3. The lead terminal 5 is a member for electrically connecting the metal cap 4 and the conductor layer 3 to an external electrode. The lead terminal 5 is made of a metal material such as nickel or stainless steel. The lead terminal 5 is a linear member, and an end thereof is located inside the slit 43 of the metal cap 4 and is joined to the metal cap 4. Thereby, compared with the case where the outer surface of the bottom part 41 of the metal cap 4 and the lead terminal 5 are joined, the metal cap 4 and the lead terminal 5 can be joined firmly. At this time, the brazing material 7 described above extends to the inside of the portion of the slit 43 located at the bottom 41, and the brazing material 7 surrounds the lead terminal 5.
　さらに、図５に示すヒータ１０においては、ろう材７が、スリット４３のうち底部４１に位置する部分の内部だけではなく、底部４１の外側にまで濡れ広がるとともに、底部４１の外側にまで濡れ広がった部分がリード端子５の端部を囲んでいる。これにより、金属キャップ４とリード端子５とをさらに強固に接合できる。 Further, in the heater 10 shown in FIG. 5, the brazing material 7 spreads not only inside the portion of the slit 43 located at the bottom 41 but also outside the bottom 41 and spreads outside the bottom 41. This portion surrounds the end of the lead terminal 5. Thereby, the metal cap 4 and the lead terminal 5 can be joined more firmly.
　さらに、スリット４３のうち先端部の幅がスリット４３のうち外側から内側に向かう部分の幅よりも大きい。具体的には、金属キャップ４の底部４１の中心部においてスリット４３の先端部が平面視したときに円形状であるとともに、このスリット４３の先端部の径（幅）がスリット４３のうち外側から内側に向かう部分の幅よりも大きい。これにより、リード端子５をスリット４３の先端部の内部に位置させて、金属キャップ４とリード端子５とを接合するときに、リード端子５がスリット４３のうち外側から内側に向かう部分にずれてしまうおそれを低減できる。このとき、リード端子５の径を、スリット４３のうち外側から内側に向かう部分の幅よりも大きく、スリット４３の先端部の径（幅）よりも小さくしてもよい。これにより、リード端子５がスリット４３のうち外側から内側に向かう部分にずれてしまうおそれをさらに低減できる。 Furthermore, the width of the tip portion of the slit 43 is larger than the width of the portion of the slit 43 from the outside toward the inside. Specifically, the tip of the slit 43 is circular when viewed from above at the center of the bottom 41 of the metal cap 4, and the diameter (width) of the tip of the slit 43 is from the outside of the slit 43. It is larger than the width of the part going inward. As a result, when the lead terminal 5 is positioned inside the tip of the slit 43 and the metal cap 4 and the lead terminal 5 are joined, the lead terminal 5 is shifted to a portion of the slit 43 from the outside toward the inside. The risk of endangering can be reduced. At this time, the diameter of the lead terminal 5 may be larger than the width of the portion from the outside toward the inside of the slit 43 and smaller than the diameter (width) of the tip portion of the slit 43. Thereby, the possibility that the lead terminal 5 is shifted to the portion from the outside toward the inside of the slit 43 can be further reduced.
　なお、本実施形態においては、スリット４３の先端部の形状が円形状であるが、これに限られない。具体的には、スリット４３の先端部は、四角形状等の多角形状であってもよい。また、スリット４３の先端部は、楕円形状または長円形状等であってもよい。なお、スリット４３の先端部の形状が多角形状の場合には、角と角とを結ぶ対角線の中で最も長い対角線の長さを幅の大きさとして見なすことができる。また、スリット４３の先端部の形状が楕円形状または長円形状の場合には、長軸の長さを幅の大きさとして見なすことができる。 In addition, in this embodiment, although the shape of the front-end | tip part of the slit 43 is circular shape, it is not restricted to this. Specifically, the distal end portion of the slit 43 may be a polygonal shape such as a square shape. Further, the tip portion of the slit 43 may be oval or oval. In addition, when the shape of the front-end | tip part of the slit 43 is a polygonal shape, the length of the longest diagonal line among the diagonal lines which connect a corner | corner can be considered as a magnitude | size of a width | variety. Moreover, when the shape of the front-end | tip part of the slit 43 is an ellipse shape or an ellipse shape, the length of a major axis can be considered as a magnitude | size of a width | variety.
　また、スリット４３のうち底部４１に位置する部分の内部にろう材７が濡れ広がるとともに、スリット４３のうち側部４２に位置する部分にはろう材７が濡れ広がっていないようにしてもよい。これにより、金属キャップ４とリード端子５とを強固に接合しつつ、金属キャップ４とセラミック体１との間に生じる熱応力を低減することができる。 Also, the brazing material 7 may spread out in the portion of the slit 43 located at the bottom 41 and the brazing material 7 may not be spread out in the portion of the slit 43 located at the side 42. Thereby, the thermal stress generated between the metal cap 4 and the ceramic body 1 can be reduced while firmly bonding the metal cap 4 and the lead terminal 5.
　また、ろう材７が、導体層３のうちセラミック体１の端面に設けられた部分だけではなく、テーパー部１１の外周面の一部に設けられた部分にまで濡れ広がっていてもよい。そして、導体層３のうちテーパー部１１の外周面の一部に設けられた部分と金属キャップ４の側部４２とが接合されていてもよい。これにより、金属キャップ４とリード端子５とをさらに強固に接合できる。 Further, the brazing material 7 may be spread not only on the portion of the conductor layer 3 provided on the end surface of the ceramic body 1 but also on a portion provided on a part of the outer peripheral surface of the tapered portion 11. And the part provided in a part of outer peripheral surface of the taper part 11 among the conductor layers 3 and the side part 42 of the metal cap 4 may be joined. Thereby, the metal cap 4 and the lead terminal 5 can be joined more firmly.
　さらに、金属キャップ４が底部４１および側部４２を有するとともに、導体層３がセラミック体１の表面のうち金属キャップ４の側部４２の開口側の端部よりも底部４１側に位置している。より詳しくは、金属キャップ４の側部４２のうち底部４１の反対側に位置する端部がテーパー部１１の外周面に接しており、テーパー部１１の外周面のうち側部４２に接する部分よりもセラミック体１の端面側に導体層３が設けられている。言い換えると、テーパー部１１の外周面のうち側部４２に接する部分には導体層３が設けられていない構成にしてもよい。これにより、導体層３と金属キャップ４とをろう材７によって接合するときに、ろう材７を導体層３と金属キャップ４との間に溜めやすくすることができる。 Further, the metal cap 4 has a bottom portion 41 and a side portion 42, and the conductor layer 3 is located closer to the bottom 41 side than the end portion on the opening side of the side portion 42 of the metal cap 4 in the surface of the ceramic body 1. . More specifically, the end portion of the side portion 42 of the metal cap 4 that is located on the opposite side of the bottom portion 41 is in contact with the outer peripheral surface of the tapered portion 11, and the portion of the outer peripheral surface of the tapered portion 11 that is in contact with the side portion 42. Also, the conductor layer 3 is provided on the end face side of the ceramic body 1. In other words, a configuration in which the conductor layer 3 is not provided on a portion of the outer peripheral surface of the tapered portion 11 that is in contact with the side portion 42 may be adopted. Thereby, when the conductor layer 3 and the metal cap 4 are joined by the brazing material 7, the brazing material 7 can be easily stored between the conductor layer 3 and the metal cap 4.
　上述したように、発熱抵抗体２の導出部２２はセラミック体１の一端の端面に引き出されている。そして、この導出部２２が引き出された部位がスリット４３と重なっており、リード端子５はスリット４３の内部に位置している。さらに、リード端子５がこの導出部２２が引き出された部位に重なるように位置している。これにより、導出部２２とリード端子５とを近付けることができるので、導出部２２とリード端子５との間の電気の流れる経路を短くすることができる。そのため、導出部２２とリード端子５との間で無駄な抵抗が発生することを抑制できる。 As described above, the lead-out portion 22 of the heating resistor 2 is drawn to the end face of one end of the ceramic body 1. The portion from which the lead-out portion 22 is drawn overlaps the slit 43, and the lead terminal 5 is located inside the slit 43. Further, the lead terminal 5 is positioned so as to overlap the portion from which the lead-out portion 22 is drawn. Thereby, since the derivation | leading-out part 22 and the lead terminal 5 can be brought close, the path | route through which the electricity flows between the derivation | leading-out part 22 and the lead terminal 5 can be shortened. Therefore, it is possible to suppress generation of useless resistance between the lead-out part 22 and the lead terminal 5.
　図１に戻って、本実施形態のグロープラグ１００は、上述のヒータ１０と、ヒータ１０のテーパー部１１側に取り付けられた筒状の金属部材６とを備えている。 Returning to FIG. 1, the glow plug 100 of the present embodiment includes the above-described heater 10 and a cylindrical metal member 6 attached to the tapered portion 11 side of the heater 10.
　金属部材６は、セラミック体１を保持するための部材である。金属部材６は、筒状の部材であって、セラミック体１の一端側を囲むように設けられている。言い換えると、金属部材６の内側にセラミック体１が挿入されている。金属部材６は、セラミック体１の一端側に引き出された他方の導出部２２に電気的に接続されている。金属部材６は、例えば、ステンレスまたは鉄（Ｆｅ）－ニッケル（Ｎｉ）－コバルト（Ｃｏ）合金から成る。 The metal member 6 is a member for holding the ceramic body 1. The metal member 6 is a cylindrical member and is provided so as to surround one end side of the ceramic body 1. In other words, the ceramic body 1 is inserted inside the metal member 6. The metal member 6 is electrically connected to the other lead-out portion 22 drawn to one end side of the ceramic body 1. The metal member 6 is made of, for example, stainless steel or iron (Fe) -nickel (Ni) -cobalt (Co) alloy.
　金属部材６とセラミック体１とは、ろう材（図示せず）によって接合されている。ろう材は、セラミック体１の端部を囲むように設けられている。言い換えると、ろう材は、セラミック体１の端部の全周に層状に設けられている。これにより、金属部材６とセラミック体１とが強固に固定される。 The metal member 6 and the ceramic body 1 are joined by a brazing material (not shown). The brazing material is provided so as to surround the end of the ceramic body 1. In other words, the brazing material is provided in layers on the entire circumference of the end of the ceramic body 1. Thereby, the metal member 6 and the ceramic body 1 are firmly fixed.
　ろう材７および金属部材６とセラミック体１とを接合するろう材としては、ガラス成分を５～３０質量％含んだ銀（Ａｇ）－銅（Ｃｕ）ろう、ＡｇろうまたはＣｕろう等を用いることができる。本実施形態のグロープラグ１００は、金属キャップ４とセラミック体１との間に生じる熱応力が低減されたヒータ１０を備えていることによって、ヒータ１０の長期信頼性が向上している。その結果、グロープラグ１００の長期信頼性が向上している。 As the brazing material for joining the brazing material 7 and the metal member 6 to the ceramic body 1, silver (Ag) -copper (Cu) brazing, Ag brazing or Cu brazing containing 5 to 30% by mass of a glass component is used. Can do. The glow plug 100 of the present embodiment includes the heater 10 in which the thermal stress generated between the metal cap 4 and the ceramic body 1 is reduced, so that the long-term reliability of the heater 10 is improved. As a result, the long-term reliability of the glow plug 100 is improved.
１：セラミック体
１１：テーパー部
２：発熱抵抗体
２１：発熱部
２２：導出部
３：導体層
４：金属キャップ
４１：底部
４２：側部
４３：スリット
５：リード端子
６：金属部材
７：ろう材
１０：ヒータ
１００：グロープラグ 1: Ceramic body 11: Tapered portion 2: Heat generating resistor 21: Heat generating portion 22: Deriving portion 3: Conductor layer 4: Metal cap 41: Bottom portion 42: Side portion 43: Slit 5: Lead terminal 6: Metal member 7: Brazing Material 10: Heater 100: Glow plug

Claims (7)

  1. 　棒状のセラミック体と、該セラミック体に埋設された発熱抵抗体と、少なくとも前記セラミック体の一端の表面に設けられて前記発熱抵抗体に電気的に接続された導体層と、前記セラミック体の前記一端を前記導体層の少なくとも一部とともに覆うように設けられた外部接続用の金属キャップとを備えており、
    該金属キャップが外周の一部に外側から内側に向かうスリットを有しているヒータ。     A rod-shaped ceramic body, a heating resistor embedded in the ceramic body, a conductor layer provided on at least one surface of the ceramic body and electrically connected to the heating resistor, and the ceramic body A metal cap for external connection provided to cover one end together with at least a part of the conductor layer;
    A heater in which the metal cap has a slit directed from the outside to the inside in a part of the outer periphery.
  2. 　前記スリットの先端部が前記金属キャップの中心に達している請求項１に記載のヒータ。 The heater according to claim 1, wherein a tip end portion of the slit reaches a center of the metal cap.
  3. 　前記スリットのうち先端部の幅が前記スリットのうち外側から内側に向かう部分の幅よりも大きい請求項１または請求項２に記載のヒータ。 The heater according to claim 1 or 2, wherein a width of a tip portion of the slit is larger than a width of a portion of the slit from the outside toward the inside.
  4. 　端部が前記導体層に接続されたリード端子をさらに有しており、該リード端子の前記端部が前記スリットの内部に位置して前記金属キャップに接合されている請求項１乃至請求項３のいずれかに記載のヒータ。 4. The lead terminal having an end portion connected to the conductor layer, and the end portion of the lead terminal is located inside the slit and joined to the metal cap. The heater in any one of.
  5. 　前記発熱抵抗体が前記セラミック体の前記一端の端面に引き出されているとともに、前記発熱抵抗体の引き出された部位が前記スリットと重なっている請求項４に記載のヒータ。 The heater according to claim 4, wherein the heating resistor is pulled out to an end face of the one end of the ceramic body, and a portion where the heating resistor is pulled out overlaps the slit.
  6. 　前記金属キャップが底部および側部を有するとともに、前記導体層が前記セラミック体の表面のうち前記金属キャップの前記側部の開口側の端部よりも底部側に位置している請求項１乃至請求項５のいずれかに記載のヒータ。 The metal cap has a bottom portion and a side portion, and the conductor layer is located on the bottom side of the surface of the ceramic body with respect to the end portion on the opening side of the side portion of the metal cap. Item 6. The heater according to any one of Items 5.
  7. 　請求項１乃至請求項６のいずれかに記載のヒータと、該ヒータの前記一端側に取り付けられた筒状の金属部材とを備えるグロープラグ。 A glow plug comprising: the heater according to any one of claims 1 to 6; and a cylindrical metal member attached to the one end of the heater.
PCT/JP2014/078675 2013-10-28 2014-10-28 Heater and glow plug WO2015064598A1 (en)

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JP2019133762A (en) * 2018-01-29 2019-08-08 京セラ株式会社 heater

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EP3064834A4 (en) 2017-06-21

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