JPH06100339B2 - Ceramic heating element - Google Patents
Ceramic heating elementInfo
- Publication number
- JPH06100339B2 JPH06100339B2 JP7744986A JP7744986A JPH06100339B2 JP H06100339 B2 JPH06100339 B2 JP H06100339B2 JP 7744986 A JP7744986 A JP 7744986A JP 7744986 A JP7744986 A JP 7744986A JP H06100339 B2 JPH06100339 B2 JP H06100339B2
- Authority
- JP
- Japan
- Prior art keywords
- heating element
- ceramic
- electrode
- support
- tip
- 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.)
- Expired - Lifetime
Links
- 239000000919 ceramic Substances 0.000 title claims description 45
- 238000010438 heat treatment Methods 0.000 title claims description 25
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 2
- 238000005452 bending Methods 0.000 description 11
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000001465 metallisation Methods 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 238000005219 brazing Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910016006 MoSi Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Resistance Heating (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、セラミック発熱体特にセラミック発熱体の電
極に関し、セラミック発熱体はディーゼルエンジンの始
動補助装置であるセラミックグロープラグおよび燃焼式
ヒータの着火源であるセラミックヒータに適用される。Description: TECHNICAL FIELD The present invention relates to a ceramic heating element, particularly an electrode of a ceramic heating element, and the ceramic heating element is a starting aid for a diesel engine, and includes a ceramic glow plug and a combustion heater. It is applied to a ceramic heater that is a fire source.
従来公知のこの種のものとしては、例えば特開昭59−96
692号公報に記載されたものがある。Examples of this type known in the prior art include, for example, JP-A-59-96.
Some are described in Japanese Patent No. 692.
これは例えば断面Ｕ字形状のセラミック発熱体素子と電
気絶縁セラミック支持体とを一体化し、かつ前記発熱体
素子に一対の電極を接続するとともに該電極を前記セラ
ミック支持体内に埋設し、このセラミック支持体の外周
にメタライズ層を介して金属ハウジングを固定し、該電
極の一方の先端側を該セラミック支持体の側面において
メタライズ層を介して金属ハウジングに電気的に接続し
た構成となっている。For example, a ceramic heating element having a U-shaped cross section and an electrically insulating ceramic support are integrated with each other, a pair of electrodes are connected to the heating element, and the electrodes are embedded in the ceramic support. A metal housing is fixed to the outer periphery of the body via a metallization layer, and one end of the electrode is electrically connected to the metal housing on the side surface of the ceramic support via the metallization layer.
〔発明が解決しようとする問題点〕 しかるに、上記従来のものによると、冷熱サイクルによ
り、上記セラミック支持体のうち上記電極の一方の先端
部の部位に亀裂が入るという問題がある。[Problems to be Solved by the Invention] However, according to the above-described conventional one, there is a problem that a crack occurs at a portion of one end portion of the electrode of the ceramic support member due to a cooling / heating cycle.
そこで、本発明者は鋭意研究の結果、上記の亀裂の原因
が電極の先端部の形状に起因していることを突き止め
た。Therefore, as a result of earnest research, the present inventor has found out that the cause of the crack is due to the shape of the tip of the electrode.
即ち、電極の先端面が平坦であると、該電極の先端面と
セラミック支持体との境界が該支持体の外面に対し直角
に伸びる直線状になり、かつ該電極は金属ハウジングと
の接続のため該側面がセラミック支持体の外面に一部露
出し、上記直線状の境界がセラミック支持体の外面にや
はり露出することになる。That is, if the tip surface of the electrode is flat, the boundary between the tip surface of the electrode and the ceramic support becomes a straight line extending at a right angle to the outer surface of the support, and the electrode is connected to the metal housing. Therefore, the side surface is partially exposed on the outer surface of the ceramic support, and the linear boundary is also exposed on the outer surface of the ceramic support.
従って、金属ハウジングとセラミック支持体との間の熱
膨張差によりメタライズ層を介して上記電極の先端部と
セラミック支持体との間に応力が発生し、該両者の間の
直線状の境界が引き金になってセラミック支持体に亀裂
が生じるのである。Therefore, a stress is generated between the tip of the electrode and the ceramic support through the metallization layer due to the difference in thermal expansion between the metal housing and the ceramic support, and the linear boundary between the two triggers. As a result, the ceramic support is cracked.
本発明は上記の点に鑑み、金属ハウジングに接続される
電極の先端部に、セラミック支持体の内側に向く傾斜面
を有する曲げ部を形成するものである。In view of the above points, the present invention is to form a bent portion having an inclined surface facing the inside of the ceramic support at the tip of the electrode connected to the metal housing.
本発明においては、セラミック支持体と電極の先端部と
の間の境界が該支持体の外面に対し直角方向の直線状に
ならないため、上記の応力が作用してもその応力を分散
でき、該応力に対し強い。In the present invention, since the boundary between the ceramic support and the tip of the electrode does not form a straight line in a direction perpendicular to the outer surface of the support, the stress can be dispersed even when the above-mentioned stress acts, Strong against stress.
従って、本発明によれば、セラミック支持体の亀裂の発
生を従来に比べて抑えることができる。Therefore, according to the present invention, the occurrence of cracks in the ceramic support can be suppressed as compared with the conventional case.
以下本発明を図に示す実施例について説明する。第１図
（ａ）〜（ｃ）において、導電性セラミックを含む材料
（MoSi2とSi3N4）で構成されたセラミック発熱体素子１
は縦断面がＵ字形状を有しており、該発熱体素子１の後
端部には電気絶縁性セラミックを含む材料（Al2O3とSi3
N4）より成るセラミック支持体２が一体的に結合せしめ
てある。該セラミック支持体２内にはタングステン線よ
り成る一対の電極3,4が埋設してあり、その一端は発熱
体素子１に電気的に接続されている。また、電極３の他
端はセラミック支持体２の外周面である側面に一部表面
を露出するよう屈曲してあり、かつその先端部はセラミ
ック支持体２の内側に向けて傾斜すよう更に屈曲してあ
る。なお、傾斜面を3a、先端の屈げ部を3bとしてある。The present invention will be described below with reference to embodiments shown in the drawings. 1 (a) to 1 (c), a ceramic heating element 1 made of a material containing conductive ceramics (MoSi 2 and Si 3 N 4 ).
Has a U-shaped longitudinal section, and the rear end portion of the heating element 1 is made of a material containing electrically insulating ceramics (Al 2 O 3 and Si 3
A ceramic support 2 of N 4 ) is integrally connected. A pair of electrodes 3 and 4 made of a tungsten wire are embedded in the ceramic support 2, one end of which is electrically connected to the heating element 1. Further, the other end of the electrode 3 is bent so as to expose a part of the surface on the side surface which is the outer peripheral surface of the ceramic support 2, and the tip end thereof is further bent so as to be inclined toward the inside of the ceramic support 2. I am doing it. The inclined surface is 3a, and the bending portion at the tip is 3b.
一方、電極４の先端はＬ字状に屈曲されてセラミック支
持体２の側面に一部表面を露出せしめてある。On the other hand, the tip of the electrode 4 is bent into an L shape so that the surface of the ceramic support 2 is partially exposed.
なお、電極3,4の上記露出表面は後述する電気接続のた
めに平坦に加工してある。The exposed surfaces of the electrodes 3 and 4 are processed flat for electrical connection described later.
次に、上記構成のセラミック発熱体を備えたディーゼル
エンジン用グロープラグの構造について説明する。第２
図において、上記セラミック発熱体のセラミック支持体
２の外面および先端端面にはニッケルメッキ層が形成し
てあり、該層を介して金属スリーブ（コバール、SUS鋼
等）５および金属キャップ（スリーブと同材質）８が銀
ろうによりろう付接合してある。なお、上記メッキ層お
よび上記銀ろう層をメタライズ層9,10としてある。Next, a structure of a glow plug for a diesel engine including the ceramic heating element having the above structure will be described. Second
In the figure, a nickel plating layer is formed on the outer surface and the tip end surface of the ceramic support 2 of the ceramic heating element, and a metal sleeve (Kovar, SUS steel, etc.) 5 and a metal cap (same as the sleeve) are formed through the nickel plating layer. Material 8 is brazed and joined by silver brazing. The plating layer and the silver brazing layer are used as metallized layers 9 and 10.
スリーブ５の外周には金属ハウジング６がろう付け固定
されており、前記発熱体の電極３は上記メタライズ層
９、スリーブ５を介してハウジング６にアースされてい
る。A metal housing 6 is brazed and fixed to the outer circumference of the sleeve 5, and the electrode 3 of the heating element is grounded to the housing 6 through the metallized layer 9 and the sleeve 5.
上記キャップ８はコネクティングピン７を介して端子ボ
ルト11に電気的に接続され、該ボルト11は電源のプラス
に接続される。なお、12は電気絶縁ブッシュ、13はナッ
ト、14は電気絶縁支持プレート、15は封口用絶縁ガラス
を示している。The cap 8 is electrically connected to the terminal bolt 11 via the connecting pin 7, and the bolt 11 is connected to the plus of the power source. In addition, 12 is an electrically insulating bush, 13 is a nut, 14 is an electrically insulating support plate, and 15 is an insulating glass for sealing.
第３図は本実施例のセラミック発熱体及び従来のセラミ
ック発熱体の抗折強度を測定した結果を示し、第３図
（ａ）は測定方法を説明する図で３点曲げ試験で抗折強
度測定を行い、スパン長Ｌは20mmとし、スパン長の真中
にアース側電極の端面がくるようにセラミック発熱体を
位置させている。第３図（ｂ）はアース側電極の端面形
状と強度の測定結果の特性図である。FIG. 3 shows the results of measuring the bending strength of the ceramic heating element of the present example and the conventional ceramic heating element, and FIG. 3 (a) is a diagram for explaining the measuring method, which is a bending strength in a three-point bending test. The measurement was performed, the span length L was set to 20 mm, and the ceramic heating element was positioned so that the end surface of the ground side electrode was located at the center of the span length. FIG. 3 (b) is a characteristic diagram of the end face shape and strength measurement result of the ground side electrode.
第４図（ａ）はアース電極の端面の曲げ込み量と抗折と
の関係を測定する方法の説明図、第４図（ｂ）は測定結
果を示す特性図で、これにより、d/D＝0.1〜1.0では抵
折強度はほとんど変わっていないが、d/D＝０の従来の
電極端面フラットな形状のときの抵折強度が20kg/mm2で
あるのに対し、多少でも曲げ込んだ本発明電極端面形状
のときの抵折強度は60〜80kg/mm2となり強度が向上して
いることが判る。FIG. 4 (a) is an explanatory view of a method for measuring the relationship between the bending amount of the end face of the ground electrode and the bending resistance, and FIG. 4 (b) is a characteristic diagram showing the measurement results. = 0.1 to 1.0, the bending strength hardly changed, but the bending strength was 20 kg / mm 2 when the conventional electrode end surface flat shape with d / D = 0 was used. It can be seen that the resistance to bending is 60 to 80 kg / mm 2 in the case of the electrode end face shape of the present invention, and the strength is improved.
この強度はセラミック支持体材質単体の強度に近いもの
である。This strength is close to that of the ceramic support material alone.
なお、本発明は上記の実施例に限定されず、次のごとき
種々の変形ができる。The present invention is not limited to the above embodiment, and various modifications can be made as follows.
（１）セラミック発熱体は金属スリーブ５を廃止してハ
ウジング６に接合してもよい。(1) The ceramic heating element may be joined to the housing 6 without the metal sleeve 5.
（２）電極の先端の形状は第５図（ａ），（ｂ）のごと
き形状でもよい。(2) The shape of the tip of the electrode may be as shown in FIGS. 5 (a) and 5 (b).
（３）前記電極３をプラス側に、電極４をアース側にし
ても勿論よい。(3) Of course, the electrode 3 may be on the plus side and the electrode 4 may be on the ground side.
第１図（ａ），（ｂ），（ｃ）は本発明になるセラミッ
ク発熱体の一実施例の構成を示し、第１図（ａ），
（ｂ）は部分断面模式図、第１図（ｃ）は第１図（ａ）
の右側面図、第２図は本発明の用途例を示す断面図、第
３図（ａ），（ｂ）は本発明になるセラミック発熱体及
び従来のセラミック発熱体の抗折強度の測定方法及び測
定結果を示す図、第４図（ａ），（ｂ）はアース側電極
端面の曲げ込み量と抗折強度との関係を示す図、第５図
（ａ），（ｂ）は本発明の他の実施例における電極先端
部の形状を示す図である。 １…セラミック発熱体素子,2…セラミック支持体,3…電
極,3a…傾斜面,3b…曲げ部,4…電極,6…金属スリーブ,7
…金属ハウジング。FIGS. 1 (a), (b) and (c) show the structure of an embodiment of the ceramic heating element according to the present invention.
(B) is a schematic partial sectional view, and FIG. 1 (c) is FIG. 1 (a).
Right side view, FIG. 2 is a cross-sectional view showing an application example of the present invention, and FIGS. 3 (a) and 3 (b) are ceramic heating elements according to the present invention and a conventional method for measuring flexural strength of ceramic heating elements. FIG. 4 (a) and FIG. 4 (b) show the relationship between the bending amount of the ground-side electrode end face and the bending strength, and FIGS. 5 (a) and 5 (b) show the present invention. It is a figure showing the shape of the electrode tip part in other examples. 1 ... Ceramic heating element, 2 ... Ceramic support, 3 ... Electrode, 3a ... Inclined surface, 3b ... Bending part, 4 ... Electrode, 6 ... Metal sleeve, 7
… Metal housing.
Claims (1)
れた発熱体素子と、該発熱体素子に一体に接合され、電
気絶縁性セラミックを含む材料で構成されたセラミック
支持体と、該支持体内部に埋設され、前記発熱体素子へ
の通電を行なう一対の電極と、前記支持体の外周に接合
された金属ハウジングとを有し、前記一対の電極のうち
少なくとも一方の電極の先端側を前記支持体の外周面に
おいて前記ハウジングに電気的に接続するとともに、該
電極の先端部に、前記支持体の内側に向く傾斜面を有す
る曲げ部を形成したことを特徴とするセラミック発熱
体。1. A heating element that is made of a material containing electrically conductive ceramic, a ceramic support that is integrally joined to the heating element and is made of a material that contains electrically insulating ceramic, and the support. It has a pair of electrodes buried inside and energizing the heating element, and a metal housing joined to the outer periphery of the support, and the tip side of at least one of the electrodes is A ceramic heating element, characterized in that it is electrically connected to the housing on the outer peripheral surface of a support, and a bent portion having an inclined surface facing the inside of the support is formed at the tip of the electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7744986A JPH06100339B2 (en) | 1986-04-02 | 1986-04-02 | Ceramic heating element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7744986A JPH06100339B2 (en) | 1986-04-02 | 1986-04-02 | Ceramic heating element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62233619A JPS62233619A (en) | 1987-10-14 |
| JPH06100339B2 true JPH06100339B2 (en) | 1994-12-12 |
Family
ID=13634326
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7744986A Expired - Lifetime JPH06100339B2 (en) | 1986-04-02 | 1986-04-02 | Ceramic heating element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06100339B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1612486B1 (en) | 2004-06-29 | 2015-05-20 | Ngk Spark Plug Co., Ltd | Glow plug |
-
1986
- 1986-04-02 JP JP7744986A patent/JPH06100339B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62233619A (en) | 1987-10-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |