JPH07109783B2 - Spark plug for internal combustion engine - Google Patents
Spark plug for internal combustion engineInfo
- Publication number
- JPH07109783B2 JPH07109783B2 JP1132760A JP13276089A JPH07109783B2 JP H07109783 B2 JPH07109783 B2 JP H07109783B2 JP 1132760 A JP1132760 A JP 1132760A JP 13276089 A JP13276089 A JP 13276089A JP H07109783 B2 JPH07109783 B2 JP H07109783B2
- Authority
- JP
- Japan
- Prior art keywords
- spark plug
- electrode
- combustion engine
- internal combustion
- spark
- 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
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
- H01T13/39—Selection of materials for electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T21/00—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs
- H01T21/02—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs of sparking plugs
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Spark Plugs (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） この発明は内燃機関に使用されるスパークプラグに関す
るものである。TECHNICAL FIELD The present invention relates to a spark plug used in an internal combustion engine.
（従来の技術） 近年、内燃機関の高性能化とともにメンテナンスフリー
の観点から点火プラグは耐火花消耗性に優れた長寿命プ
ラグが益々要望されている。かかる長寿命化を図るため
に点火プラグは従来、Ni合金等の耐熱性、耐食性金属か
らなる中心電極、外側電極の火花放電部に貴金属を用い
ることによって改善することがよく知られており、この
ため主にPt,Pt−Ir合金等の貴金属材の棒状チップまた
は薄板チップを電気抵抗溶接、電子ビーム溶接、レーザ
ー溶接によって接合して用いることが提案されている。(Prior Art) In recent years, from the viewpoint of high performance of an internal combustion engine and maintenance-free, there is an increasing demand for a long-life spark plug having excellent spark wear resistance. In order to achieve such a long life, the spark plug has been conventionally known to be improved by using a noble metal in the spark discharge portion of the outer electrode, the center electrode made of a heat-resistant and corrosion-resistant metal such as Ni alloy, and the like. Therefore, it has been proposed to use rod-shaped chips or thin plate chips of noble metal materials such as Pt and Pt-Ir alloys by joining them by electric resistance welding, electron beam welding or laser welding.
（発明が解決しようとする課題） しかし、前者は高価な貴金属材の使用量が多くコスト高
となり、後者は貴金属板より円盤状のチップを打抜き、
これを接合するものであるからチップ以外の部分が多
く、歩留りが30％も悪化してコスト高の要因となった。
しかも、溶解法によって製造されたPt−Ir合金は伸性及
び脆性を併せ持ち、且つ2300℃以上という高融点の合金
であるので加工が困難であり、ワイヤー状の加工するた
めには作業を高熱内で行なわざるを得ず、しかもそれを
切断するに際し、せん断力による割れやクラックが生じ
易く、複雑形状への安定した加工は不可能であった。
又、放電加工はPt−Ir合金の融点が高いために、時間が
かかるという問題があった。(Problems to be solved by the invention) However, the former uses a large amount of expensive precious metal material, resulting in high cost, and the latter punches a disk-shaped chip from a precious metal plate,
Since this is a joint, there are many parts other than the chip, and the yield deteriorated by 30%, which was a factor of high cost.
Moreover, since the Pt-Ir alloy produced by the melting method has both ductility and brittleness, and is a high melting point alloy of 2300 ° C or more, it is difficult to process it. In addition, cracks and cracks due to shearing force tended to occur when cutting it, and stable processing into a complicated shape was impossible.
Further, there is a problem that the electric discharge machining takes time because the melting point of the Pt-Ir alloy is high.
そこで、この発明は上記従来のものの持つ欠点を改善す
るものであり、貴金属の浪費がなく、コストの低減が可
能で、且つ火花消耗性に優れた貴金属材を火花放電部の
チップとして使用することによってプラグの長寿命化を
達成しようとするものである。Therefore, the present invention is to improve the drawbacks of the above-mentioned conventional ones, without wasting precious metal, and it is possible to reduce the cost, and to use a precious metal material excellent in spark exhaustion as a chip of the spark discharge part. It is intended to achieve a longer life of the plug.
（課題を解決するための手段） そのために、発火部電極をイリジウムにより構成し、そ
のイリジウム粉末を金型プレス成形、CIP成形、押出成
形、射出成形等により成形した上、脱脂し、真空中或い
は非酸化性ないし還元雰囲気下で1700〜2200℃の温度で
焼結し、かつ、焼結密度が90％以上となるように焼結し
てなるものである。(Means for solving the problem) Therefore, the ignition part electrode is composed of iridium, and the iridium powder is molded by die press molding, CIP molding, extrusion molding, injection molding, etc., and then degreased in vacuum or It is formed by sintering at a temperature of 1700 to 2200 ° C. in a non-oxidizing or reducing atmosphere and at a sintering density of 90% or more.
（作用） 上記構成を備えるので、貴金属の浪費がなくて量産性に
富むことによりコストを低減でき、しかも溶解法によっ
ては成形加工が困難であった複雑形状で且つ火花消耗性
に優れた発火部電極チップを使用することによりスパー
クプラグの長寿命化を図ることができる。(Operation) Since the above configuration is provided, it is possible to reduce costs by not wasting precious metals and being highly producible, and in addition, the ignition part has a complicated shape that was difficult to mold by the melting method and is excellent in spark consumption. The life of the spark plug can be extended by using the electrode tip.
（実施例） この発明を図に示す実施例により更に説明する。（１）
は、この発明の第１の実施例である内燃機関用スパーク
プラグであり、この内燃機関用スパークプラグ（１）
は、先端に、後述するように製造されて火花放電部とな
る発火部電極（６）がそれをとりまくアルミナや窒化物
系セラミック（AlN,Si3N4）の絶縁体（２）軸孔（８）
の先端孔内に挿設されて絶縁体（２）と同時に焼成され
ている。この絶縁体（２）は、内燃機関に取り付ける時
に使用するネジ部（５）と上記発火部電極（６）と対向
する位置に外側電極（４）を配置する主体金具（３）
と、絶縁体（２）内の軸孔（８）内に発火部電極（６）
と電気抵抗溶接された金属製の中間電極（７）、或は導
電性セラミック粉末ないしはセラミック粉末に金属をコ
ートした粉末が充填されてなる中間電極（７）をガラス
シール（９）とともに封入される端子電極（10）から構
成されるものである。そして発火部電極（６）は、イリ
ジウム粉末を金型プレス成形、CIP成形、押出成形或い
は射出成形等により成形した上脱脂し、真空中或いは非
酸化性ないし還元雰囲気下で焼結密度が90％以上となる
ように焼結したものを、第３図に示すように、先端径
（ａ）0.8mm、基底部径（ｂ）1.2mm、全長（ｃ）2mm、
基底部長（ｄ）0.5mm、鍔角α45゜とする鍔（11）付き
形状とする。(Example) The present invention will be further described with reference to an example shown in the drawings. (1)
Is a spark plug for an internal combustion engine according to a first embodiment of the present invention, and the spark plug (1) for an internal combustion engine
Is an insulator (2) of alumina or nitride ceramics (AlN, Si 3 N 4 ) around the tip of which the ignition part electrode (6), which will be the spark discharge part, will be formed at the tip (6). 8)
Is inserted into the tip hole of the and is fired at the same time as the insulator (2). This insulator (2) is a metallic shell (3) in which an outer electrode (4) is arranged at a position opposed to the screw part (5) used when attaching to an internal combustion engine and the ignition part electrode (6).
And the ignition part electrode (6) in the shaft hole (8) in the insulator (2).
And an intermediate electrode (7) made of metal electrically resistance-welded, or an intermediate electrode (7) made by filling conductive ceramic powder or ceramic powder with a metal coating, together with a glass seal (9). It is composed of a terminal electrode (10). The ignition part electrode (6) is formed by molding iridium powder by die press molding, CIP molding, extrusion molding, injection molding, etc. and degreasing it, and has a sintered density of 90% in vacuum or in a non-oxidizing or reducing atmosphere. As shown in FIG. 3, the sintered product obtained as described above has a tip diameter (a) of 0.8 mm, a base portion diameter (b) of 1.2 mm, a total length (c) of 2 mm,
The base length (d) is 0.5 mm and the flange angle is α45 °.
表１には、プレス成形密度比、焼成雰囲気及びその条件
における焼結密度の関係を示したものであり、この発火
部電極（６）材作成に際し、焼成雰囲気を大気中とする
とイリジウムが酸化して黒色のIr酸化物が形成されて揮
発性が促進されるため、焼成工程は非酸化性、より好ま
しくは還元雰囲気下ないし真空中で行われなければなら
ない。又、その焼成工程における焼結温度は1700〜2200
℃であり、2000℃以上がより好ましい。更に、焼結密度
が低いと、作成した電極材に残存する多くの空孔が、火
花放電の高エネルギーによる温度上昇を局所化するた
め、電極材の消耗が加速させるので、焼結密度は、第６
図に示すように少なくとも90％以上は必要である。又、
その際、表２に示すように２次焼成を行うことにより、
焼結密度を一層高めることができる。Table 1 shows the relationship between the press molding density ratio, the firing atmosphere and the sintering density under the conditions. When the firing part electrode (6) material was produced, iridium was oxidized when the firing atmosphere was in the air. Since the black Ir oxide is formed to promote volatility, the firing process should be performed in a non-oxidizing, more preferably reducing atmosphere or in vacuum. The sintering temperature in the firing process is 1700-2200.
C, and more preferably 2000 C or higher. Furthermore, when the sintered density is low, many pores remaining in the created electrode material localize the temperature rise due to the high energy of spark discharge, which accelerates the consumption of the electrode material. Sixth
As shown in the figure, at least 90% or more is necessary. or,
At that time, by performing secondary firing as shown in Table 2,
The sintered density can be further increased.
以上の構成を具えるので、発火部電極（６）として市販
のイリジウム地金粉末をプレス成形密度比が66.3％とな
るように金型プレス後、水素雰囲気中で2200℃で60分間
焼結させて、焼結密度の92.5％としたものを、更にAr雰
囲気中で1400℃で60分間２次焼結し、熱間静水圧成形に
より第３図に示す鍔付き形状とした試料Ｋを使用して火
花消耗テストを行ったところ、溶解法により作成したPt
−Ir合金と同等の優れた耐火花消耗性を得ることができ
た。With the above configuration, commercially available iridium metal powder for the ignition part electrode (6) is pressed into a die at a press molding density ratio of 66.3% and then sintered at 2200 ° C for 60 minutes in a hydrogen atmosphere. Then, the sintered density of 92.5% was secondarily sintered at 1400 ° C for 60 minutes in an Ar atmosphere, and a sample K with a collar shape shown in Fig. 3 was formed by hot isostatic pressing. When a spark consumption test was performed, Pt created by the melting method
-It was possible to obtain the same excellent spark wear resistance as the Ir alloy.
第４図はこの発明の第２の実施例を示したスパークプラ
グ（1A）であって、発火部電極（６）の形状は、第５図
に示すように径（ｅ）0.5mm、長さ（ｆ）1.5mmの円筒形
状としたものであり、この発火部電極（６）は内部に銅
に封入したニッケル合金からなる中心電極（12）の先端
凹部（13）内に載置されるとともに電子ビーム溶接、或
はレーザー溶接（Ｌ）によって接合されている。この中
心電極（12）は絶縁体（２）の軸孔（８）内に挿入され
て鍔部（14）において係止されて同様にガラスシール
（９）でもって加熱封着され、全体金具（３）の内腔に
固定されたスパークプラグである。更にこの発火部電極
（６）の構成はイグナイタプラグにおいても有用であ
る。FIG. 4 shows a spark plug (1A) showing a second embodiment of the present invention, wherein the ignition part electrode (6) has a diameter (e) of 0.5 mm and a length of 0.5 mm as shown in FIG. (F) It has a cylindrical shape of 1.5 mm, and this ignition part electrode (6) is placed in the tip recessed part (13) of the center electrode (12) made of a nickel alloy enclosed in copper. It is joined by electron beam welding or laser welding (L). The center electrode (12) is inserted into the shaft hole (8) of the insulator (2), locked at the flange (14), and similarly heat-sealed with a glass seal (9), so that the entire metal fitting ( It is a spark plug fixed to the lumen of 3). Further, the structure of the ignition part electrode (6) is also useful in an igniter plug.
（発明の効果） 以上のとおり、イリジウム粉末地金により発火部電極を
構成することにより、火花耐久性に優れた長寿命プラグ
を得ることができるとともに、材料の無駄がなく量産に
優れ、コストの低減を図ることができる。 (Effects of the Invention) As described above, by configuring the ignition part electrode with iridium powder metal, it is possible to obtain a long-life plug with excellent spark durability, and to achieve mass production without wasting material and to reduce costs. It can be reduced.
第１図は、この発明の第１の実施例である内燃機関用ス
ハパークプラグの部分断面図、第２図は、第１図の発火
部拡大の部分断面図、第３図は、第２図の発火部電極の
拡大図、第４図は、この発明の第２の実施例であるスパ
ークプラグの部分断面図、第５図は、第４図の中心電極
先端の拡大図、第６図は焼結密度と消耗割合を示すグラ
フである。 １、1A……内燃機関用スパークプラグ、２……絶縁体、
３……主体金具、４……外側電極、５……ネジ部、６…
…発火部電極、７……中間電極、８……軸孔、９……ガ
ラスシール、10……端子電極、11……鍔、12……中心電
極FIG. 1 is a partial sectional view of a spark plug for an internal combustion engine which is a first embodiment of the present invention, FIG. 2 is a partial sectional view of an enlarged ignition part of FIG. 1, and FIG. FIG. 4 is an enlarged view of the ignition part electrode of FIG. 4, FIG. 4 is a partial sectional view of a spark plug which is a second embodiment of the present invention, and FIG. 5 is an enlarged view of the center electrode tip of FIG. Is a graph showing sintered density and consumption rate. 1, 1A ... Spark plug for internal combustion engine, 2 ... Insulator,
3 ... metal shell, 4 ... outer electrode, 5 ... screw part, 6 ...
… Ignition part electrode, 7 …… Intermediate electrode, 8 …… Shaft hole, 9 …… Glass seal, 10 …… Terminal electrode, 11 …… Pipe, 12 …… Center electrode
Claims (1)
中或いは非酸化性ないし還元雰囲気下で1700〜2200℃の
温度で焼結し、かつ、焼結密度が90％以上となるように
焼結してなる発火部電極を有する内燃機関用スパークプ
ラグ。1. Iridium powder is molded, degreased, sintered in a vacuum or in a non-oxidizing or reducing atmosphere at a temperature of 1700 to 2200 ° C., and has a sintered density of 90% or more. A spark plug for an internal combustion engine having an ignition part electrode formed by sintering.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1132760A JPH07109783B2 (en) | 1989-05-29 | 1989-05-29 | Spark plug for internal combustion engine |
| DE1990633451 DE69033451T2 (en) | 1989-05-29 | 1990-05-29 | spark plug |
| EP90305797A EP0400950B1 (en) | 1989-05-29 | 1990-05-29 | Spark plug |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1132760A JPH07109783B2 (en) | 1989-05-29 | 1989-05-29 | Spark plug for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH031475A JPH031475A (en) | 1991-01-08 |
| JPH07109783B2 true JPH07109783B2 (en) | 1995-11-22 |
Family
ID=15088918
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1132760A Expired - Lifetime JPH07109783B2 (en) | 1989-05-29 | 1989-05-29 | Spark plug for internal combustion engine |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0400950B1 (en) |
| JP (1) | JPH07109783B2 (en) |
| DE (1) | DE69033451T2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9627857B2 (en) | 2014-02-24 | 2017-04-18 | Ngk Spark Plug Co., Ltd. | Spark plug |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3000955B2 (en) * | 1996-05-13 | 2000-01-17 | 株式会社デンソー | Spark plug |
| DE19745165A1 (en) * | 1997-10-13 | 1999-04-15 | Volkswagen Ag | Spark plug for internal combustion engines |
| DE10103045A1 (en) | 2001-01-24 | 2002-07-25 | Bosch Gmbh Robert | Manufacturing ignition plug electrode involves joining electrode to precious metal using heat generated by continuously operating laser beam, causing melting in boundary region |
| JP4123117B2 (en) | 2003-09-17 | 2008-07-23 | 株式会社デンソー | Spark plug |
| JP2006260988A (en) * | 2005-03-17 | 2006-09-28 | Ngk Spark Plug Co Ltd | Spark plug |
| US7443089B2 (en) | 2006-06-16 | 2008-10-28 | Federal Mogul World Wide, Inc. | Spark plug with tapered fired-in suppressor seal |
| US8485857B1 (en) | 2012-01-24 | 2013-07-16 | General Electric Company | Method of producing a spark gap for an electrode support using sacrificial material |
| US8912713B2 (en) | 2012-01-24 | 2014-12-16 | General Electric Company | Method of producing an electrode support using brazing |
| JP5492244B2 (en) | 2012-04-09 | 2014-05-14 | 日本特殊陶業株式会社 | Spark plug |
| US10418787B2 (en) * | 2017-05-11 | 2019-09-17 | Denso International America, Inc. | Ground electrode pad for spark plug |
| DE102018101512B4 (en) | 2018-01-24 | 2020-03-19 | Federal-Mogul Ignition Gmbh | Method of making an electrode assembly, electrode assembly, and spark plug |
| DE102018105941B4 (en) * | 2018-03-14 | 2021-09-02 | Federal-Mogul Ignition Gmbh | Spark plug ignition tip, spark plug assembly, and method of making a spark plug ignition tip |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1099387A (en) * | 1965-08-25 | 1968-01-17 | Johnson Matthey Co Ltd | Improvements in and relating to sparking plug electrodes |
| US3466158A (en) * | 1966-01-10 | 1969-09-09 | Int Nickel Co | Compound precious metal article having layer containing iridium or ruthenium |
| FR1490828A (en) * | 1966-08-24 | 1967-08-04 | Johnson | spark plug electrode |
| US3548239A (en) * | 1968-09-03 | 1970-12-15 | Champion Spark Plug Co | Spark plug electrode construction |
| JPS5657282A (en) * | 1979-10-13 | 1981-05-19 | Ngk Spark Plug Co | Ignition plug |
| JPS6188478A (en) * | 1984-10-05 | 1986-05-06 | 日本特殊陶業株式会社 | Core electrode for spark plug |
| JPS62226592A (en) * | 1986-03-28 | 1987-10-05 | 日本特殊陶業株式会社 | Ignition plug |
| CH676525A5 (en) * | 1988-07-28 | 1991-01-31 | Battelle Memorial Institute |
-
1989
- 1989-05-29 JP JP1132760A patent/JPH07109783B2/en not_active Expired - Lifetime
-
1990
- 1990-05-29 EP EP90305797A patent/EP0400950B1/en not_active Expired - Lifetime
- 1990-05-29 DE DE1990633451 patent/DE69033451T2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9627857B2 (en) | 2014-02-24 | 2017-04-18 | Ngk Spark Plug Co., Ltd. | Spark plug |
Also Published As
| Publication number | Publication date |
|---|---|
| DE69033451T2 (en) | 2000-06-08 |
| DE69033451D1 (en) | 2000-03-16 |
| EP0400950A1 (en) | 1990-12-05 |
| JPH031475A (en) | 1991-01-08 |
| EP0400950B1 (en) | 2000-02-09 |
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