JPH07282960A - Ceramic heater - Google Patents
Ceramic heaterInfo
- Publication number
- JPH07282960A JPH07282960A JP6621994A JP6621994A JPH07282960A JP H07282960 A JPH07282960 A JP H07282960A JP 6621994 A JP6621994 A JP 6621994A JP 6621994 A JP6621994 A JP 6621994A JP H07282960 A JPH07282960 A JP H07282960A
- Authority
- JP
- Japan
- Prior art keywords
- heating element
- ceramic
- tip
- ceramic heater
- embedded
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
- 239000000919 ceramic Substances 0.000 title claims abstract description 65
- 238000010438 heat treatment Methods 0.000 claims description 46
- 239000000843 powder Substances 0.000 claims description 9
- 239000003870 refractory metal Substances 0.000 claims description 5
- 238000002485 combustion reaction Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 abstract description 13
- 230000002093 peripheral effect Effects 0.000 abstract description 3
- 239000000463 material Substances 0.000 abstract description 2
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 239000000758 substrate Substances 0.000 description 7
- 230000008646 thermal stress Effects 0.000 description 6
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 4
- 229910052721 tungsten Inorganic materials 0.000 description 4
- 239000010937 tungsten Substances 0.000 description 4
- 238000000465 moulding Methods 0.000 description 3
- 230000003405 preventing effect Effects 0.000 description 3
- 229910016006 MoSi Inorganic materials 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 238000007731 hot pressing Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910001080 W alloy Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- YXTPWUNVHCYOSP-UHFFFAOYSA-N bis($l^{2}-silanylidene)molybdenum Chemical compound [Si]=[Mo]=[Si] YXTPWUNVHCYOSP-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910021343 molybdenum disilicide Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- DECCZIUVGMLHKQ-UHFFFAOYSA-N rhenium tungsten Chemical compound [W].[Re] DECCZIUVGMLHKQ-UHFFFAOYSA-N 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Landscapes
- Resistance Heating (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はセラミックヒータに関す
るものであり、例えばセラミックグロープラグに用いら
れる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic heater, which is used, for example, in a ceramic glow plug.
【０００２】[0002]
【従来の技術】本出願人の出願になる特開平１ー３１７
１７０号公報は、電気絶縁性のセラミック部材からなる
棒状の基体と、この基体に埋設された導電性セラミック
材料を含む発熱体と、基体に埋設されて発熱体の両端に
個別に接続される高融点金属部材からなる一対の電極線
とを備え、これら電極線の先端部が発熱体の両端面から
発熱体の内部に埋設されるセラミックヒータを開示して
いる。上記公報では、発熱体としては、Ｍｏ、Ｓｉ、Ｃ
を成分とする導電性セラミック粉末を絶縁性セラミック
粉末に分散して形成した導電性セラミック焼結体が開示
され、電極線としては例えばタングステンが一例として
挙げられている。2. Description of the Related Art Japanese Patent Application Laid-Open No. 1-317 filed by the present applicant
No. 170 discloses a rod-shaped base body made of an electrically insulating ceramic member, a heating element containing a conductive ceramic material embedded in the base body, and a heating element embedded in the base body and individually connected to both ends of the heating element. Disclosed is a ceramic heater including a pair of electrode wires made of a melting point metal member, and the tip ends of these electrode wires being embedded in the heating element from both end surfaces of the heating element. In the above publication, the heating element is Mo, Si, C.
There is disclosed a conductive ceramic sintered body formed by dispersing a conductive ceramic powder containing as a component in an insulating ceramic powder, and tungsten is cited as an example of the electrode wire.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上記従
来のセラミックヒータを用いたグロープラグをディーゼ
ルエンジンに装着して耐久試験を行った結果、長時間の
使用後、基体にクラックが発生する場合があった。そこ
で、クラック発生部分を分解調査すると、発熱体の端面
からその内部に埋設された電極線の端面周縁からクラッ
クが発生しており、そしてこのクラックが、発熱体（導
電性セラミック焼結体）を通じて絶縁性セラミック焼結
体の表面まで進展していることが確認された。However, as a result of mounting the glow plug using the above-mentioned conventional ceramic heater on a diesel engine and performing a durability test, cracks may occur on the substrate after long-term use. It was Therefore, when the cracked portion was disassembled and investigated, a crack was generated from the end face of the heating element to the edge of the end face of the electrode wire embedded therein, and this crack was generated through the heating element (conductive ceramic sintered body). It was confirmed that the surface of the insulative ceramic sintered body had spread to the surface.
【０００４】このクラック発生の原因について考察する
と、電極線の端面が約９０度のエッジとなっているの
で、電極線の端面が埋設される発熱体すなわち上記導電
性セラミック焼結体はエッジ状の切り欠きを有すること
になる。このため、エンジンの燃焼による大温度差の温
度変化サイクルが頻繁にこの部位に作用したり、始動の
ための通電時の急激な温度上昇がこの部位に作用するの
で、電極線と発熱体との線膨張率の差に起因して熱応力
（熱ストレス）が生じ、この熱ストレスが電極線の端面
周縁近傍の発熱体に集中すると考えられる。Considering the cause of this crack generation, since the end face of the electrode wire has an edge of about 90 degrees, the heating element in which the end face of the electrode wire is buried, that is, the above-mentioned conductive ceramic sintered body has an edge shape. Will have a notch. Therefore, a temperature change cycle with a large temperature difference due to combustion of the engine frequently acts on this portion, or a rapid temperature rise at the time of energization for starting acts on this portion, so that the electrode wire and the heating element It is considered that thermal stress (thermal stress) is generated due to the difference in the coefficient of linear expansion, and this thermal stress is concentrated on the heating element near the edge of the end surface of the electrode wire.
【０００５】本発明は上記考察に基づきなされたもので
あり、電極線の発熱体側の端面近傍に生じるクラックを
防止可能なセラミックヒータを提供することを、その目
的としている。The present invention has been made based on the above consideration, and an object thereof is to provide a ceramic heater capable of preventing cracks generated in the vicinity of the end surface of the electrode wire on the heating element side.
【０００６】[0006]
【課題を解決するための手段】本発明の第１の構成は、
電気絶縁性のセラミック部材からなる棒状の基体と、導
電性セラミック部材又は高融点金属部材を含む電気抵抗
体からなるとともに前記基体に埋設される発熱体と、高
融点金属部材からなるとともに前記基体に埋設されて前
記発熱体の両端に個別に接続される一対の電極線とを備
え、前記両電極線の先端は、前記発熱体の両端に個別に
接続されるセラミックヒータにおいて、前記電極線の先
端部は、前記基体又は前記発熱体を構成するセラミック
体に埋設されるとともに先細形状を有することを特徴と
している。The first structure of the present invention is as follows.
A rod-shaped base made of an electrically insulating ceramic member, a heating element made of an electric resistor containing a conductive ceramic member or a refractory metal member and embedded in the base, and a base made of a refractory metal member applied to the base. In a ceramic heater, which is embedded and has a pair of electrode wires individually connected to both ends of the heating element, the tips of both electrode wires being ceramic heaters individually connected to both ends of the heating element. The part is embedded in the ceramic body forming the base body or the heating element and has a tapered shape.
【０００７】本発明の第２の構成は上記第１の構成に加
えて、前記電極線の先端部が、セラミック粉末を含む焼
結体からなる前記発熱体の端面から前記発熱体の内部に
埋設される点を特徴としている。本発明の第３の構成は
上記第１又は第２の構成に加えて、前記電極線の先端部
の端面が面取りされている点を特徴としている。In a second structure of the present invention, in addition to the above-mentioned first structure, the tip of the electrode wire is embedded in the inside of the heating element from the end surface of the heating element made of a sintered body containing ceramic powder. It is characterized by the point. The third configuration of the present invention is characterized in that, in addition to the first or second configuration, the end face of the tip end portion of the electrode wire is chamfered.
【０００８】なお、この面取りは、Ｃ面取りでも、Ｒ面
取りでもよい。本発明の第４の構成は上記第１〜第３の
いずれかの構成に加えて、前記電極線の先端部が、部分
球面状又は円錐面状に形成されている点を特徴としてい
る。なお、ここでいう部分球面状とは半球面状、一部球
面状、半楕円球面状、一部楕円球面状など、端面前面に
わたって丸みを帯びた凸曲面形状をいう。また、円錐面
状とは径方向断面が円形、楕円径または角が面取りされ
た断面を有し、先端に向けて次第に先細となる形状をい
う。なお、この円錐面状を採用する場合、その先端部を
切ることが好ましく、また切ってできた端面の周縁は面
取りすることが好ましい。The chamfering may be C chamfering or R chamfering. The fourth structure of the present invention is characterized in that, in addition to the structure of any of the first to third structures, the tip end portion of the electrode wire is formed in a partially spherical shape or a conical surface shape. The term "partially spherical surface" as used herein refers to a semi-spherical surface, a partially spherical surface, a semi-elliptical spherical surface, a partially elliptical spherical surface, etc., and a rounded convex curved surface shape over the front surface of the end surface. Further, the conical surface shape means a shape having a circular radial section, an elliptical diameter, or a chamfered corner, and gradually tapering toward the tip. When adopting this conical surface shape, it is preferable to cut the tip portion, and it is preferable to chamfer the peripheral edge of the cut end surface.
【０００９】本発明の第５の構成は上記第１〜第５のい
ずれかの構成の前記セラミックヒータを有する内燃機関
用グロープラグである。A fifth structure of the present invention is a glow plug for an internal combustion engine, which has the ceramic heater of any one of the first to fifth structures.
【００１０】[0010]
【作用及び発明の効果】本発明の第１の構成によれば、
基体又は発熱体を構成するセラミック体に埋設される電
極線の先端部を先細形状とすることにより、電極線の先
端面周縁近傍のクラック発生が防止できることがわかっ
た。これは、この部位の熱ストレスが、電極線の先端部
を先細形状としたため緩和されたためと考えらることが
できる。According to the first structure of the present invention,
It has been found that by forming the tip end portion of the electrode wire embedded in the ceramic body forming the base body or the heating element into a tapered shape, it is possible to prevent the occurrence of cracks near the periphery of the tip end surface of the electrode wire. It can be considered that this is because the thermal stress at this portion was relaxed because the tip of the electrode wire was tapered.
【００１１】本発明の第２の構成では、上記クラック防
止効果を一層向上できた。これは、発熱体を構成する導
電性セラミック焼結体が基体を構成する絶縁性セラミッ
ク体よりもクラックを生じ易いにもかかわらず、電極線
の先端部が先細形状であるので熱ストレスが緩和される
ためであると考えられる。本発明の第３の構成によれば
上記第１又は第２の構成において更に、電極線の先端部
の端面を面取りすることにより発熱体の先端部を先細形
状としている。このようにすれば、加工が簡単である
が、クラック防止効果は充分大きいことがわかった。In the second structure of the present invention, the crack prevention effect can be further improved. This is because although the conductive ceramic sintered body forming the heating element is more likely to crack than the insulating ceramic body forming the base body, the tip of the electrode wire is tapered, so that thermal stress is relieved. It is thought to be for the reason. According to a third configuration of the present invention, in the first or second configuration, the end portion of the tip of the electrode wire is further chamfered so that the tip of the heating element is tapered. It has been found that the above-mentioned method makes the processing easy, but has a sufficiently large effect of preventing cracks.
【００１２】本発明の第４の構成は上記第１〜３の構成
において更に、電極線の先端部を部分球面状又は円錐面
状に形成しているので、クラック防止効果を一層向上で
きることがわかった。これは、この部位における電極線
の端面の曲率変化の急変をより一層、低減できるためと
考えられる。本発明の第５の構成によれば、長寿命の内
燃機関用グロープラグを実現することができる。In the fourth structure of the present invention, in addition to the above-mentioned first to third structures, the tip of the electrode wire is further formed in a partially spherical shape or a conical surface shape, so that it is understood that the crack preventing effect can be further improved. It was It is considered that this is because the sudden change in the curvature of the end surface of the electrode wire at this portion can be further reduced. According to the fifth configuration of the present invention, a long-life glow plug for an internal combustion engine can be realized.
【００１３】[0013]
【実施例】以下、本発明を具体的実施例により説明す
る。 （実施例１）図１は本発明のセラミックヒータ１の実施
例を示した断面図であり、図２はその要部の拡大図を示
す。EXAMPLES The present invention will be described below with reference to specific examples. (Embodiment 1) FIG. 1 is a sectional view showing an embodiment of a ceramic heater 1 of the present invention, and FIG. 2 is an enlarged view of the main part thereof.
【００１４】このセラミックヒータ１は、円棒状の基体
３と、基体３の先端部に埋設されるＵ字状の発熱体２
と、基体３の基端部及び中央部に埋設される断面円形の
電極線４、５とからなる。基体３は、Ｓｉ3 Ｎ4 からな
る絶縁性セラミック粉末に、ＭｏＳｉ2 からなる導電体
セラミック粉末を少量分散させた断面円形の絶縁性セラ
ミック焼結体からなる。The ceramic heater 1 includes a base 3 having a circular rod shape and a U-shaped heating element 2 embedded in the tip of the base 3.
And electrode wires 4 and 5 having a circular cross section, which are embedded in the base end portion and the central portion of the base body 3. The base 3 is made of an insulating ceramic sintered body having a circular cross section in which a small amount of a conductive ceramic powder made of MoSi 2 is dispersed in an insulating ceramic powder made of Si 3 N 4 .
【００１５】発熱体２は、ＭｏＳｉ2 からなる導電体セ
ラミック粉末と、Ｓｉ3 Ｎ4 からなる絶縁性セラミック
粉末とを含む断面略半円形の導電性セラミック焼結体で
ある。電極線４、５の基端部は基体１の外周に露出して
部分円筒面４ｃ，５ｃとなっており、それらの先端部は
発熱体２の両端面から発熱体２の内部に埋設されてい
る。電極線４、５は、タングステン、モリブデン等の高
融点金属またはその合金からなるが、ここでは断面円形
のタングステン線とされている。部分円筒面４ｃ，５ｃ
の曲率半径は基体３の半径に等しくされている。The heating element 2 is a conductive ceramic sintered body having a substantially semicircular cross section containing a conductive ceramic powder made of MoSi 2 and an insulating ceramic powder made of Si 3 N 4 . The base ends of the electrode wires 4 and 5 are exposed at the outer periphery of the base body 1 to form partial cylindrical surfaces 4c and 5c, and their tip ends are embedded in the heating element 2 from both end surfaces of the heating element 2. There is. The electrode wires 4 and 5 are made of a refractory metal such as tungsten or molybdenum or an alloy thereof, but are tungsten wires having a circular cross section here. Partial cylindrical surfaces 4c, 5c
Has a radius of curvature equal to that of the base body 3.
【００１６】本実施例において重要な点は、図２に示す
ように、電極線４、５の先端面４ａ、５ａの周縁にＲ面
取り部４ｂ、５ｂが施されている点にある。この実施例
では、基体３の直径は３．５ｍｍ、長さは４５ｍｍとさ
れ、発熱体２は半径が１．２ｍｍの半円形とされ、電極
線４、５の直径は０．６ｍｍとされている。そして、Ｒ
面取り部４ｂ、５ｂの曲率半径は０．１ｍｍとされ、電
極線４、５の発熱体２への埋設深さは１ｍｍとされてい
る。An important point in this embodiment is that, as shown in FIG. 2, R chamfered portions 4b and 5b are provided on the peripheral edges of the tip surfaces 4a and 5a of the electrode wires 4 and 5, respectively. In this embodiment, the substrate 3 has a diameter of 3.5 mm and a length of 45 mm, the heating element 2 has a semicircular shape with a radius of 1.2 mm, and the electrode wires 4 and 5 have a diameter of 0.6 mm. There is. And R
The radius of curvature of the chamfered portions 4b and 5b is 0.1 mm, and the burying depth of the electrode wires 4 and 5 in the heating element 2 is 1 mm.
【００１７】本実施例のセラミックヒータ１をディーゼ
ルエンジンのグロープラグに採用した例を図３に示す。
電極線４、５の部分円筒面４ｃ，５ｃが露出する基体３
の側面には各々ニッケルメッキが施されている。金属の
中空パイプ６が基体３の中央部に嵌着、ロウ付けされて
おり、中空パイプ６はセラミックヒータ１を保持すると
ともに、電極線５の部分円筒面５ｃと電気的に接続され
ている。FIG. 3 shows an example in which the ceramic heater 1 of this embodiment is used in a glow plug of a diesel engine.
Substrate 3 in which the partial cylindrical surfaces 4c and 5c of the electrode wires 4 and 5 are exposed
The sides of each are plated with nickel. A metal hollow pipe 6 is fitted and brazed to the center of the base body 3. The hollow pipe 6 holds the ceramic heater 1 and is electrically connected to the partial cylindrical surface 5c of the electrode wire 5.
【００１８】中空パイプ６の外周には図示しないエンジ
ンへの取付けネジ１０ａを有する両端開口筒状の金属ハ
ウジング１０の先端部が嵌着、ロウ付けされている。一
方、基体３の基端部に導出された電極線４の部分円筒面
４ｃには、金属キャップ７がロウ付けされており、金属
キャップ７には金属線８の一端が溶接され、金属線８の
他端は中軸９の先端に溶接されている。中軸９の基端部
に形成された雄ネジ部９１は図示しない電源と接続され
る。中軸９はハウジング１０内に嵌入されており、中軸
９はハウジング１０からガラスシール１１および絶縁ブ
ッシュ１２により電気的に絶縁され、絶縁ブッシュ１２
は雄ネジ部９１に螺着されたナット１３により固定され
ている。On the outer circumference of the hollow pipe 6, a tip end portion of a metal housing 10 having a cylindrical shape with both ends opened and having a mounting screw 10a for mounting on an engine (not shown) is fitted and brazed. On the other hand, a metal cap 7 is brazed to the partial cylindrical surface 4c of the electrode wire 4 led out to the base end of the base body 3, and one end of the metal wire 8 is welded to the metal cap 7 so that the metal wire 8 is welded. The other end of is welded to the tip of the center shaft 9. The male screw portion 91 formed at the base end portion of the center shaft 9 is connected to a power source (not shown). The center shaft 9 is fitted in the housing 10, and the center shaft 9 is electrically insulated from the housing 10 by the glass seal 11 and the insulating bush 12.
Is fixed by a nut 13 screwed to the male screw portion 91.
【００１９】このような構成とすることにより、不図示
の電源から中軸９、金属線８、金属キャップ７、電極線
４、発熱体２、電極線５、中空パイプ６、ハウジング１
０を介して図示しないエンジンブロックへ電流が通電可
能となっている。セラミックヒータ１の製造方法につい
て説明すると、電極線４、５を金型内の所定位置にセッ
トした状態で発熱体２を射出成形し、次にこの電極線
４、５及び発熱体２の一体物を金型内の所定位置にセッ
トした状態で基体３を射出成形した成形品をホットプレ
スにより焼結させる。しかるのち、焼結体の外周を研削
して形成する。With such a structure, a power source (not shown), a center wire 9, a metal wire 8, a metal cap 7, an electrode wire 4, a heating element 2, an electrode wire 5, a hollow pipe 6, and a housing 1 are provided.
A current can be passed through 0 to an engine block (not shown). Explaining the method for manufacturing the ceramic heater 1, the heating element 2 is injection-molded with the electrode wires 4, 5 set at predetermined positions in the mold, and then the electrode wires 4, 5 and the heating element 2 are integrally formed. The molded article obtained by injection molding the substrate 3 is set in a predetermined position in the mold and sintered by hot pressing. Then, the outer periphery of the sintered body is ground to form.
【００２０】以下、本発明の作用効果を表す試験結果を
説明する。ただし、発熱体２は、二珪化モリブデン（Ｍ
ｏＳｉ2 ）３０質量部、窒化珪素（Ｓｉ3 Ｎ4 ）７０質
量部とした。試験は、２０００ｃｃディーゼルエンジン
を用い、電極線４、５の先端面４ａ、５ａで熱応力が発
生しやすいよう冷熱試験を行った。条件は、高い温度条
件として、前記セラミックグロープラグの通電がＯＮの
状態でＷ．Ｏ．Ｔ（全負荷）４０００ｒｐｍを１分、低
温条件として、前記セラミックグロープラグの通電がＯ
ＦＦの状態で、アイドリングで１分実施するサイクル
を、２００００サイクル運転した。The test results showing the action and effect of the present invention will be described below. However, the heating element 2 is molybdenum disilicide (M
30 parts by mass of oSi 2 ) and 70 parts by mass of silicon nitride (Si 3 N 4 ). For the test, a 2000 cc diesel engine was used, and a cold heat test was performed so that thermal stress is easily generated on the tip surfaces 4a, 5a of the electrode wires 4, 5. The conditions are high temperature conditions such that the W.W. O. T (full load) 4000 rpm for 1 minute under low temperature condition, the energization of the ceramic glow plug is O
In the FF state, 20,000 cycles of idling for 1 minute were performed.
【００２１】この後、基体３の表面のクラックの有無を
観察した。その結果を表１に示す。表１において、Ｒは
Ｒ面取り部４ｂ、５ｂの曲率半径（単位ｍｍ）である。After that, the presence or absence of cracks on the surface of the substrate 3 was observed. The results are shown in Table 1. In Table 1, R is a radius of curvature (unit: mm) of the R chamfered portions 4b and 5b.
【００２２】[0022]
【表１】 Ｒ０．００のものは、４本中３本に基体３の表面にクラ
ックが発生し、Ｒ０．０３ｍｍのものは、４本中１本に
基体３の表面にクラックが発生した。しかし、Ｒ０．０
５ｍｍ以上のものは、クラックの発生がない。従って、
Ｒ０．０５ｍｍ以上のＲ面取りを行うことにより、信頼
性が大幅に向上することが分かる。[Table 1] In the case of R0.00, cracks occurred on the surface of the base body 3 in 3 out of 4 pieces, and in the case of R0.03 mm, cracks occurred on the surface of the base body 3 in 1 out of 4 pieces. However, R0.0
If the thickness is 5 mm or more, no crack is generated. Therefore,
It can be seen that reliability is significantly improved by performing R chamfering of R0.05 mm or more.
【００２３】以上、本発明のＲ面取りの効果について述
べたが、Ｃ面取りについても同様の試験を行った。その
結果を表２に示す。Although the effect of the R chamfering of the present invention has been described above, the same test was performed for the C chamfering. The results are shown in Table 2.
【００２４】[0024]
【表２】 表２から、Ｃ０．００のものは、前述のＲ０．００のも
のに相当し、４本中３本に絶縁性セラミック体３の表面
にクラックが発生し、Ｃ０．０３ｍｍのものは、４本中
１本に絶縁性セラミック体３の表面にクラックが発生し
た。しかし、Ｃ０．０５ｍｍ以上のものは、クラックの
発生がない。従って、Ｃ０．０５ｍｍ以上のＣ面取りを
行うことにより、信頼性が大幅に向上することが分か
る。[Table 2] From Table 2, C0.00's correspond to those of R0.00 described above, 3 out of 4 have cracks on the surface of the insulating ceramic body 3, and C 0.03 mm have 4's. One of them had a crack on the surface of the insulating ceramic body 3. However, if the C is 0.05 mm or more, no crack is generated. Therefore, it is understood that reliability is significantly improved by performing C chamfering of C0.05 mm or more.
【００２５】以上、Ｒ面取り、Ｃ面取りの効果について
述べたが、結局、セラミックヒータ１の発熱部２に電流
を供給する電極線４，５の先端面４ａ，５ａに曲率半径
０．０５ｍｍ以上のＲ面取り、または、Ｃ面取りが施し
てあれば、厳しい冷熱の繰り返しにおいても、基体３の
表面にクラックが発生することなく、信頼性の高いセラ
ミックヒータを提供することができる。The effects of the R chamfering and the C chamfering have been described above, but in the end, the tip surfaces 4a, 5a of the electrode wires 4, 5 for supplying the current to the heating portion 2 of the ceramic heater 1 have a radius of curvature of 0.05 mm or more. If the R chamfering or the C chamfering is performed, it is possible to provide a highly reliable ceramic heater without cracking on the surface of the substrate 3 even when severe cold heat is repeated.
【００２６】更に、このＲ面取り又はＣ面取りの他の作
用効果を図４を参照して説明する。上記説明したよう
に、発熱体２の成形にあたって電極線４、５を金型１０
０内の所定位置にセットした状態で発熱体２を射出成形
する場合、金型１００内のキャビティ１０１において電
極線４、５の周囲の円筒状のキャビティ１０２は径方向
に狭小であり、軸方向に長くなり、射出口１０３からキ
ャビティ１０２内に発熱体原料を射出する際、この円筒
状のキャビティ１０２内への充填が容易ではない。本実
施例によれば、電極線４、５の端面が面取りされている
ので、この円筒状のキャビティ１０２内への充填が容易
となり、充填不良による発熱体２の成形不良を格段に低
減することができる。Further, another function and effect of this R chamfering or C chamfering will be described with reference to FIG. As described above, when molding the heating element 2, the electrode wires 4 and 5 are attached to the mold 10
When the heating element 2 is injection-molded in a state where it is set at a predetermined position within 0, the cylindrical cavity 102 around the electrode wires 4 and 5 in the cavity 101 in the mold 100 is narrow in the radial direction, Since the heating element material is injected into the cavity 102 through the injection port 103, it is not easy to fill the cylindrical cavity 102. According to the present embodiment, since the end faces of the electrode wires 4 and 5 are chamfered, it becomes easy to fill the cylindrical cavity 102, and the defective molding of the heating element 2 due to defective filling can be significantly reduced. You can
【００２７】以下に、その他の実施例を説明する。ただ
し、実施例１と共通機能要素には同一符号を付す。 （実施例２）他の実施例を図５に示す。この実施例は電
極線４、５の先端面４ａ，５ａを半球状としたものであ
り、更に優れた効果が得られた。 （実施例３）他の実施例を図６に示す。Other embodiments will be described below. However, the same functional elements as those in the first embodiment are designated by the same reference numerals. (Embodiment 2) Another embodiment is shown in FIG. In this embodiment, the tip surfaces 4a and 5a of the electrode wires 4 and 5 are formed in a hemispherical shape, and a more excellent effect was obtained. (Embodiment 3) Another embodiment is shown in FIG.
【００２８】この実施例は電極線４、５の先端面４ａ，
５ａを切頭円錐状とし、その先端面を面取りしたもので
あり、更に優れた効果が得られた。 （実施例４）他の実施例を図７に示す。この実施例は発
熱体２としてタングステン又はタングステン合金の小径
（ここでは直径０．２ｍｍ）のフィラメントを使用した
ものであり、このフィラメント２は、電極線４、５と一
体に形成できる他、電極線４、５に巻装してもよい。こ
の場合、電極線４、５の先端面４ａ，５ａは基体３の絶
縁性セラミック部材に埋設されるが、同様の効果を奏す
ることは明らかである。In this embodiment, the tip surfaces 4a of the electrode wires 4 and 5,
5a was frusto-conical and the tip surface was chamfered, and a further excellent effect was obtained. (Embodiment 4) Another embodiment is shown in FIG. In this embodiment, a small-diameter (here, diameter 0.2 mm) filament of tungsten or a tungsten alloy is used as the heating element 2. This filament 2 can be formed integrally with the electrode wires 4 and 5, and It may be wound around four or five. In this case, the tip surfaces 4a and 5a of the electrode wires 4 and 5 are embedded in the insulating ceramic member of the base body 3, but it is clear that the same effect can be obtained.
【００２９】この実施例のセラミックヒータは、電極線
４、５及びフィラメント２を型内にセットして絶縁性セ
ラミック粉を充填、成形し、その成形品をホットプレス
した後、外周を略円形に研削して形成される。表１、２
にこのセラミックヒータの試験結果を示す。試験条件は
実施例１の場合と同じである。この結果、実施例１と同
じ効果を奏することがわかった。 （実施例５）他の実施例を以下に説明する。In the ceramic heater of this embodiment, the electrode wires 4 and 5 and the filament 2 are set in a mold, the insulating ceramic powder is filled and molded, the molded product is hot-pressed, and then the outer periphery is made substantially circular. It is formed by grinding. Tables 1 and 2
The test results of this ceramic heater are shown in. The test conditions are the same as in Example 1. As a result, it was found that the same effect as in Example 1 was obtained. (Fifth Embodiment) Another embodiment will be described below.
【００３０】この実施例は発熱体として、タングステン
レニウムを主成分とする導電ペーストを厚膜状又は薄膜
状に印刷したものであり、この場合も電極線の先端面は
基体に埋設されるが、同様の効果が得られた。この実施
例のセラミックヒータは、少なくとも１個の絶縁性セラ
ミックのグリーンシート又は成形体の表面に導電性ペー
ストで抵抗パターンを印刷し、この抵抗パターンと電極
線とを接触させた状態でグリーンシート又は成形体を積
層し、この積層品をホットプレスした後、外周を略円形
に研削して形成される。In this embodiment, as a heating element, a conductive paste containing tungsten rhenium as a main component is printed in a thick film form or a thin film form. In this case as well, the tip end face of the electrode wire is embedded in the substrate. Similar effects were obtained. In the ceramic heater of this embodiment, a resistance pattern is printed on the surface of at least one insulating ceramic green sheet or molded body with a conductive paste, and the green sheet or the green sheet is formed in a state where the resistance pattern is in contact with the electrode wire. It is formed by laminating molded bodies, hot pressing the laminated body, and then grinding the outer periphery into a substantially circular shape.
【００３１】表１、２にこのセラミックヒータの試験結
果を示す。試験条件は実施例１の場合と同じである。こ
の結果、実施例１と同じ効果を奏することがわかった。Tables 1 and 2 show the test results of this ceramic heater. The test conditions are the same as in Example 1. As a result, it was found that the same effect as in Example 1 was obtained.
【図１】本発明のセラミックヒータの一実施例を示す断
面図である。FIG. 1 is a sectional view showing an embodiment of a ceramic heater of the present invention.
【図２】図１の要部拡大断面図である。FIG. 2 is an enlarged cross-sectional view of a main part of FIG.
【図３】図１のセラミックヒータをグロープラグに採用
した実施例を示す断面図である。FIG. 3 is a sectional view showing an embodiment in which the ceramic heater of FIG. 1 is adopted in a glow plug.
【図４】発熱体２の成形工程を示す模式断面図である。FIG. 4 is a schematic cross-sectional view showing a molding step of the heating element 2.
【図５】本発明のセラミックヒータの他の実施例を示す
断面図である。FIG. 5 is a sectional view showing another embodiment of the ceramic heater of the present invention.
【図６】本発明のセラミックヒータの他の実施例を示す
断面図である。FIG. 6 is a sectional view showing another embodiment of the ceramic heater of the present invention.
【図７】本発明のセラミックヒータの他の実施例を示す
断面図である。FIG. 7 is a cross-sectional view showing another embodiment of the ceramic heater of the present invention.
１ セラミックヒータ ２ 発熱体 ３ 基体 ４ 電極線 ５ 電極線 1 Ceramic heater 2 Heating element 3 Base 4 Electrode wire 5 Electrode wire
Claims (5)
の基体と、導電性セラミック部材又は高融点金属部材を
含む電気抵抗体からなるとともに前記基体に埋設される
発熱体と、高融点金属部材からなるとともに前記基体に
埋設されて前記発熱体の両端に個別に接続される一対の
電極線とを備え、前記両電極線の先端は、前記発熱体の
両端に個別に接続されるセラミックヒータにおいて、 前記電極線の先端部は、前記基体又は前記発熱体を構成
するセラミック体に埋設されるとともに先細形状を有す
ることを特徴とするセラミックヒータ。1. A rod-shaped base made of an electrically insulating ceramic member, an electric resistor including a conductive ceramic member or a refractory metal member, and a heating element embedded in the base, and a refractory metal member. And a pair of electrode wires that are embedded in the base body and individually connected to both ends of the heating element, and the tip ends of the two electrode wires are ceramic heaters that are individually connected to both ends of the heating element. A ceramic heater characterized in that a tip portion of the electrode wire is embedded in a ceramic body forming the base body or the heating element and has a tapered shape.
含む焼結体からなる前記発熱体の端面から前記発熱体の
内部に埋設される請求項１記載のセラミックヒータ。2. The ceramic heater according to claim 1, wherein a tip portion of the electrode wire is embedded inside the heating element from an end surface of the heating element made of a sintered body containing ceramic powder.
ている請求項１、２のいずれか記載のセラミックヒー
タ。3. The ceramic heater according to claim 1, wherein the end surface of the tip of the electrode wire is chamfered.
錐面状に形成されている請求項１〜３のいずれか記載の
セラミックヒータ。4. The ceramic heater according to claim 1, wherein the tip of the electrode wire is formed in a partially spherical shape or a conical surface shape.
ックヒータを有する内燃機関用グロープラグ。5. A glow plug for an internal combustion engine, comprising the ceramic heater according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06621994A JP3269253B2 (en) | 1994-04-04 | 1994-04-04 | Ceramic heater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06621994A JP3269253B2 (en) | 1994-04-04 | 1994-04-04 | Ceramic heater |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07282960A true JPH07282960A (en) | 1995-10-27 |
| JP3269253B2 JP3269253B2 (en) | 2002-03-25 |
Family
ID=13309509
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP06621994A Expired - Fee Related JP3269253B2 (en) | 1994-04-04 | 1994-04-04 | Ceramic heater |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3269253B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6204481B1 (en) * | 1998-09-11 | 2001-03-20 | Ngk Spark Plug Co., Ltd. | Glow plug with ceramic heating element having electrode attached thereto |
| JP2006186014A (en) * | 2004-12-27 | 2006-07-13 | Hitachi Kokusai Electric Inc | Semiconductor manufacturing equipment |
| JP2011508950A (en) * | 2007-12-29 | 2011-03-17 | サン−ゴバン セラミックス アンド プラスティクス，インコーポレイティド | Ceramic heating element |
| WO2012147920A1 (en) * | 2011-04-27 | 2012-11-01 | 京セラ株式会社 | Heater and glow plug comprising same |
| CN102970780A (en) * | 2011-08-30 | 2013-03-13 | 株式会社电装 | Ceramic heater and gas sensor element |
| KR101477559B1 (en) * | 2010-10-27 | 2014-12-30 | 쿄세라 코포레이션 | Heater, and glow plug provided with same |
| KR101504631B1 (en) * | 2011-04-27 | 2015-03-20 | 쿄세라 코포레이션 | Heater and glow plug provided with same |
-
1994
- 1994-04-04 JP JP06621994A patent/JP3269253B2/en not_active Expired - Fee Related
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6204481B1 (en) * | 1998-09-11 | 2001-03-20 | Ngk Spark Plug Co., Ltd. | Glow plug with ceramic heating element having electrode attached thereto |
| JP2006186014A (en) * | 2004-12-27 | 2006-07-13 | Hitachi Kokusai Electric Inc | Semiconductor manufacturing equipment |
| JP2011508950A (en) * | 2007-12-29 | 2011-03-17 | サン−ゴバン セラミックス アンド プラスティクス，インコーポレイティド | Ceramic heating element |
| KR101477559B1 (en) * | 2010-10-27 | 2014-12-30 | 쿄세라 코포레이션 | Heater, and glow plug provided with same |
| WO2012147920A1 (en) * | 2011-04-27 | 2012-11-01 | 京セラ株式会社 | Heater and glow plug comprising same |
| KR101504631B1 (en) * | 2011-04-27 | 2015-03-20 | 쿄세라 코포레이션 | Heater and glow plug provided with same |
| JP5701979B2 (en) * | 2011-04-27 | 2015-04-15 | 京セラ株式会社 | Heater and glow plug equipped with the same |
| JP2015099795A (en) * | 2011-04-27 | 2015-05-28 | 京セラ株式会社 | Heater and glow plug equipped with the same |
| US9491805B2 (en) | 2011-04-27 | 2016-11-08 | Kyocera Corporation | Heater and glow plug provided with same |
| JP2017098257A (en) * | 2011-04-27 | 2017-06-01 | 京セラ株式会社 | Heater and glow plug having the same |
| US10299317B2 (en) | 2011-04-27 | 2019-05-21 | Kyocera Corporation | Heater and glow plug provided with same |
| US8841589B2 (en) | 2011-08-30 | 2014-09-23 | Denso Corporation | Ceramic heater and gas sensor element |
| CN102970780A (en) * | 2011-08-30 | 2013-03-13 | 株式会社电装 | Ceramic heater and gas sensor element |
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| Publication number | Publication date |
|---|---|
| JP3269253B2 (en) | 2002-03-25 |
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