JPH0574549A - Spark plug - Google Patents
Spark plugInfo
- Publication number
- JPH0574549A JPH0574549A JP23293191A JP23293191A JPH0574549A JP H0574549 A JPH0574549 A JP H0574549A JP 23293191 A JP23293191 A JP 23293191A JP 23293191 A JP23293191 A JP 23293191A JP H0574549 A JPH0574549 A JP H0574549A
- Authority
- JP
- Japan
- Prior art keywords
- specific gravity
- metal
- electrode
- section
- outer electrode
- 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.)
- Pending
Links
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- Spark Plugs (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、主体金具の先端に外
側電極を溶接したスパークプラグにおける、外側電極の
折損防止に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to prevention of breakage of an outer electrode in a spark plug in which the outer electrode is welded to the tip of a metal shell.
【０００２】[0002]
【従来の技術】自動車エンジンなどのガソリン機関の高
速回転、高出力化に伴い、外側電極の折損の発生が増大
する。この要因としては、バルブの着座振動、燃焼の衝
撃波、エンジンの振動などにより、外側電極が強制振動
させられることにある。従って高温強度の増大など材質
の改良や、寸法の増大で共振周波数を高くすることによ
り対処が成されている。2. Description of the Related Art As gasoline engines such as automobile engines rotate at higher speeds and have higher output, breakage of outer electrodes increases. This is because the outer electrode is forcibly vibrated by the seating vibration of the valve, the shock wave of combustion, the vibration of the engine, and the like. Therefore, measures have been taken by improving the material such as increasing the high temperature strength and increasing the resonance frequency by increasing the size.
【０００３】[0003]
【発明が解決しようとする課題】外側電極の折損に対し
ては、高温強度、高温耐蝕性の高い白金（Ｐｔ）−イリ
ジウム（Ｉｒ）合金の使用が有効であり、自動車レース
用エンジンのスパークプラグにおいて実用されている
が、確実な効果は得られていない。また、たとえば上記
Ｐｔ−Ｉｒ合金の外側電極を、１辺が０．８ｍｍの正方
形断面から１．０ｍｍの正方形断面に拡大し破壊強度を
増大させても、先端部の重量が増大しすぎ、慣性重量が
増大して逆効果になり易い。この発明の目的は、強制振
動による外側電極の折損が有効に防止できるスパークプ
ラグの提供にある。With respect to breakage of the outer electrode, it is effective to use a platinum (Pt) -iridium (Ir) alloy having high temperature strength and high temperature corrosion resistance, and spark plugs for automobile racing engines. Although it has been put to practical use in Japan, no reliable effect has been obtained. Further, for example, even if the outer electrode of the Pt-Ir alloy is expanded from a square cross section with one side of 0.8 mm to a square cross section of 1.0 mm to increase the fracture strength, the weight of the tip portion increases too much and inertia is increased. The weight tends to increase and the adverse effect tends to occur. An object of the present invention is to provide a spark plug that can effectively prevent breakage of the outer electrode due to forced vibration.
【０００４】[0004]
【課題を解決するための手段】この発明のスパークプラ
グは、筒状主体金具に、軸心に中心電極が貫設された絶
縁碍子を固着し、主体金具の先端に溶接した外側電極
と、前記中心電極の先端部との間に火花放電間隙を形成
するスパークプラグにおいて、外側電極を、比重の大き
い耐熱、耐火花消耗性金属から成り、少なくとも中心電
極に面する内側部分を含む高比重部と、該内側部より比
重の小さい金属から成り、前記高比重部に沿って一体に
設けられた低比重部とで形成し、低比重部の金属の断面
積を、外側電極の断面積の１／５以上としたことを特徴
とする。A spark plug according to the present invention comprises an outer electrode having a cylindrical metal shell, to which an insulator having a center electrode penetrating the shaft is fixed, and an outer electrode welded to the tip of the metal shell. In a spark plug that forms a spark discharge gap with the tip of the center electrode, the outer electrode is composed of a heat-resistant and spark-consumable metal having a large specific gravity, and a high specific gravity portion including at least an inner portion facing the center electrode. , A low specific gravity portion integrally formed along the high specific gravity portion, the cross sectional area of the metal of the low specific gravity portion being 1 / It is characterized by being 5 or more.
【０００５】[0005]
【発明の作用、効果】この発明のスパークプラグでは、
外側電極を比重の異なる金属の接合で形成しいるので、
強制振動による共振が生じにくい。これにより外側電極
の折損が防止できる。With the spark plug of the present invention,
Since the outer electrode is formed by joining metals with different specific gravities,
Resonance due to forced vibration hardly occurs. This can prevent breakage of the outer electrode.
【０００６】[0006]
【実施例】図１は、この発明にかかるスパークプラグを
示す。このスパークプラグは、先端に棒状外側電極１が
傾斜して溶接された筒状の主体金具２内に、軸穴３１付
き絶縁碍子３を嵌め込んでいる。絶縁碍子３は、主体金
具２内周に設けた段座２１にパッキン２２を介して絶縁
碍子３の座面３２を係止し、主体金具頭部２３をかしめ
ることにより固定されている。前記軸穴３１には、先端
側に中心電極５が挿入され、その先端部５Ａが絶縁碍子
３の先端より突出し、後端鍔部５Ｂが軸穴の段部３３に
当接している。軸穴３１には、導電性ガラスシール４１
に挟まれたモノシリック抵抗体４２、および中軸４が加
熱封着されている。外側電極１の先端部の中心電極側面
と、中心電極５の先端部５Ａとの間は、火花放電間隙と
なっている。1 shows a spark plug according to the present invention. In this spark plug, an insulator 3 with a shaft hole 31 is fitted in a tubular metal shell 2 having a rod-shaped outer electrode 1 inclined and welded to its tip. The insulator 3 is fixed by locking the seat surface 32 of the insulator 3 to the stepped seat 21 provided on the inner circumference of the metal shell 2 via the packing 22 and caulking the metal shell head 23. The center electrode 5 is inserted into the shaft hole 31 on the front end side, the front end portion 5A thereof projects from the front end of the insulator 3, and the rear end flange portion 5B abuts on the step portion 33 of the shaft hole. A conductive glass seal 41 is provided in the shaft hole 31.
The monolithic resistor 42 sandwiched between and the center pole 4 are heat-sealed. There is a spark discharge gap between the center electrode side surface of the tip of the outer electrode 1 and the tip 5A of the center electrode 5.
【０００７】外側電極１は、図２に示すごとく、１辺が
０．８ｍｍの正方形断面を有し、Ｐｔ−Ｉｒ合金製母材
（高比重部）１１の軸芯に、１５．０重量％のクロム
（Ｃｒ）、８．０重量％の鉄（Ｆｅ）を含むニッケル
（Ｎｉ）合金製芯材（軽比重部）１２を埋設してなる。
母材１１の金属の比重は、芯材１２の金属の比重の２倍
以上、芯材１２の断面積は、外側電極全体の１／５以上
となっている。この構成により、外側電極１は、外周部
のＰｔ−Ｉｒ合金で高温強度を保持しながら重量低減に
よる慣性力の低下がなされ、かつ強制振動に対し共振し
にくくなるので、耐折損性が向上する。As shown in FIG. 2, the outer electrode 1 has a square cross section with one side of 0.8 mm, and the Pt-Ir alloy base material (high specific gravity portion) 11 has a shaft center of 15.0% by weight. Of nickel (Ni) alloy containing chromium (Cr) and 8.0% by weight of iron (Fe) (light specific gravity part) 12 is embedded.
The specific gravity of the metal of the base material 11 is twice or more the specific gravity of the metal of the core material 12, and the cross-sectional area of the core material 12 is 1/5 or more of the entire outer electrode. With this configuration, the outer electrode 1 has a lower Pt—Ir alloy in the outer peripheral portion while maintaining high-temperature strength to reduce the inertial force due to weight reduction, and is less likely to resonate with forced vibration, so that the breakage resistance is improved. ..
【０００８】図３は、外側電極１の断面積に対する芯材
１２の断面積の断面積比をパラメータとした外側電極１
の折損発生に関する実験データを示す。図１に示すスパ
ークプラグを、４サイクル、６気筒、３０００ｃｃのガ
ソリン機関に装着し、６０００ｒｐｍ、全負荷とアイド
リングとの繰り返しの冷熱サイクルを３００時間行った
ときの外側電極の折損発生率を測定した。断面積比が１
／５（０．２）以上のとき折損の発生が低下することが
分かる。尚これは外側電極１の全重量に対する芯材１２
の重量の重量比に換算すると、約１０％以上に相当す
る。また同様の測定を母材１１の金属の比重と、芯材１
２の金属の比重との比重比について行った結果、母材１
１の金属の比重は、芯材１２の金属の比重の２倍以上あ
ることが望ましいことが判明した。なお、Ｐｔ合金の比
重が２１、Ｎｉの比重が９であることから、これら金属
を主体としてそれぞれ母材１１および芯材１２を構成す
れば、比重比は２以上となる。FIG. 3 shows the outer electrode 1 with the cross-sectional area ratio of the cross-sectional area of the core material 12 to the cross-sectional area of the outer electrode 1 as a parameter.
The experimental data on the occurrence of breakage are shown. The spark plug shown in FIG. 1 was attached to a 4-cycle, 6-cylinder, 3000 cc gasoline engine, and the breakage rate of the outer electrode was measured when a repeated thermal cycle of 6000 rpm, full load and idling was performed for 300 hours. .. Cross-sectional area ratio is 1
It can be seen that when / 5 (0.2) or more, the occurrence of breakage decreases. In addition, this is the core material 12 with respect to the total weight of the outer electrode 1.
When converted to the weight ratio of the weight of, it corresponds to about 10% or more. In addition, the same measurement was performed for the specific gravity of the metal of the base material 11 and the core material 1.
As a result of the specific gravity ratio with the specific gravity of the metal of No. 2, base material 1
It has been found that the specific gravity of the metal No. 1 is preferably twice or more the specific gravity of the metal of the core material 12. Since the specific gravity of the Pt alloy is 21 and the specific gravity of Ni is 9, if the base material 11 and the core material 12 are mainly composed of these metals, the specific gravity ratio becomes 2 or more.
【０００９】母材１１には、白金、パラジウム、イリジ
ウム、またはこれらの合金、金パラジウム合金などの耐
熱、耐火花消耗性貴金属が使用できる。また芯材１２に
は、ニッケル、ニッケル合金、銅、または銅合金が使用
できる。ニッケル系金属は比重が小さい金属中では高温
強度が高い利点があり、銅系の芯材は熱伝導性が高く外
側電極１の過昇温を防止できる利点がある。For the base material 11, a heat-resistant and spark-consumable noble metal such as platinum, palladium, iridium, alloys thereof, gold-palladium alloy or the like can be used. Further, for the core material 12, nickel, nickel alloy, copper, or copper alloy can be used. The nickel-based metal has an advantage that the high temperature strength is high among metals having a small specific gravity, and the copper-based core material has an advantage that the outer electrode 1 can be prevented from overheating due to its high thermal conductivity.
【００１０】図４は、他の実施例を示す。（イ）は母材
層６１、６１間に芯材６２を挟んだクラッド材で外側電
極６を構成している。（ロ）は高比重部７１と低比重部
７２とを積層して外側電極７を形成している。（ハ）は
芯材１２が母材１１の先端部を除く部分に埋設してあ
る。（ニ）は母材１１の軸芯に芯材１２を埋設した棒状
電極を、略Ｌ字形に曲げている。これらの構成において
も、上記と同様の作用、効果を奏する。尚、これらの外
側電極は、クラッド材または圧着材から製造される。FIG. 4 shows another embodiment. In (a), the outer electrode 6 is composed of a clad material in which the core material 62 is sandwiched between the base material layers 61, 61. In (b), the outer electrode 7 is formed by laminating the high specific gravity portion 71 and the low specific gravity portion 72. In (c), the core material 12 is embedded in the portion of the base material 11 excluding the tip portion. In (d), a rod-shaped electrode in which the core material 12 is embedded in the axis of the base material 11 is bent into a substantially L-shape. Also in these configurations, the same operation and effect as described above are achieved. Incidentally, these outer electrodes are manufactured from a clad material or a pressure-bonded material.
【図面の簡単な説明】[Brief description of drawings]
【図１】この発明のスパークプラグの断面図である。FIG. 1 is a sectional view of a spark plug of the present invention.
【図２】外側電極の拡大断面図である。FIG. 2 is an enlarged cross-sectional view of an outer electrode.
【図３】耐久実験結果を示すグラフである。FIG. 3 is a graph showing a result of an endurance test.
【図４】外側電極の他の実施例の先端部断面図である。FIG. 4 is a sectional view of a tip portion of another embodiment of the outer electrode.
１ 外側電極 ２ 主体金具 ３ 絶縁碍子 ４ 中軸 ５ 中心電極 １１ 母材（高比重部） １２ 芯材（低比重部） 1 Outer electrode 2 Metal shell 3 Insulator 4 Middle shaft 5 Center electrode 11 Base material (high specific gravity part) 12 Core material (low specific gravity part)
Claims (1)
された絶縁碍子を固着し、主体金具の先端に溶接した外
側電極と、前記中心電極の先端部との間に火花放電間隙
を形成するスパークプラグにおいて、 外側電極を、比重の大きい耐熱、耐火花消耗性金属から
成り、少なくとも中心電極に面する内側部を含む高比重
部と、該内側部より比重の小さい金属から成り、前記内
側部に沿って一体に設けられた低比重部とで形成し、低
比重部の金属の断面積を、外側電極の断面積の１／５以
上としたことを特徴とするスパークプラグ。1. A spark discharge between an outer electrode welded to the tip of the metal shell, and an insulator fixed to the tubular metal shell, the insulator having the center electrode penetrating the shaft center, and the tip of the center electrode. In the spark plug forming the gap, the outer electrode is made of a heat-resistant and spark-depleting metal having a large specific gravity, a high specific gravity portion including at least the inner portion facing the center electrode, and a metal having a lower specific gravity than the inner portion. And a low specific gravity portion integrally provided along the inner portion, wherein the cross-sectional area of the metal of the low specific gravity portion is ⅕ or more of the cross-sectional area of the outer electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23293191A JPH0574549A (en) | 1991-09-12 | 1991-09-12 | Spark plug |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23293191A JPH0574549A (en) | 1991-09-12 | 1991-09-12 | Spark plug |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0574549A true JPH0574549A (en) | 1993-03-26 |
Family
ID=16947094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23293191A Pending JPH0574549A (en) | 1991-09-12 | 1991-09-12 | Spark plug |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0574549A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002222686A (en) * | 2000-11-24 | 2002-08-09 | Denso Corp | Spark plug and its manufacturing method |
| JP2003059620A (en) * | 2001-08-10 | 2003-02-28 | Ngk Spark Plug Co Ltd | Spark plug |
| US7148612B2 (en) | 2001-09-26 | 2006-12-12 | Federal-Mogul Ignition (Uk) Limited | Spark plug with inclined electrode spark surfaces |
| US7288879B2 (en) | 2004-09-01 | 2007-10-30 | Ngk Spark Plug Co., Ltd. | Spark plug having ground electrode including precious metal alloy portion containing first, second and third components |
-
1991
- 1991-09-12 JP JP23293191A patent/JPH0574549A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002222686A (en) * | 2000-11-24 | 2002-08-09 | Denso Corp | Spark plug and its manufacturing method |
| JP2003059620A (en) * | 2001-08-10 | 2003-02-28 | Ngk Spark Plug Co Ltd | Spark plug |
| JP4638093B2 (en) * | 2001-08-10 | 2011-02-23 | 日本特殊陶業株式会社 | Spark plug |
| US7148612B2 (en) | 2001-09-26 | 2006-12-12 | Federal-Mogul Ignition (Uk) Limited | Spark plug with inclined electrode spark surfaces |
| US7288879B2 (en) | 2004-09-01 | 2007-10-30 | Ngk Spark Plug Co., Ltd. | Spark plug having ground electrode including precious metal alloy portion containing first, second and third components |
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