JPH05198349A - Spark plug for internal combustion engine - Google Patents
Spark plug for internal combustion engineInfo
- Publication number
- JPH05198349A JPH05198349A JP4031476A JP3147692A JPH05198349A JP H05198349 A JPH05198349 A JP H05198349A JP 4031476 A JP4031476 A JP 4031476A JP 3147692 A JP3147692 A JP 3147692A JP H05198349 A JPH05198349 A JP H05198349A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- noble metal
- metal tip
- electrode material
- spark plug
- 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
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- Spark Plugs (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は，発火部に貴金属チップ
を設けた内燃機関用スパークプラグの電極材料に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode material for a spark plug for an internal combustion engine, in which a noble metal tip is provided on an ignition part.
【０００２】[0002]
【従来技術】従来，内燃機関用のスパークプラグにおい
ては，中心電極及び接地電極の電極材料としてニッケル
基合金を用いたものがある。そして，その発火部には，
上記ニッケル基合金のみを用いるもの，該ニッケル基合
金を母材としてその表面に白金，白金合金からなる貴金
属チップを溶接したものとがある。即ち，エンジンの燃
焼室内で常時放電を行うスパークプラグの電極は，耐熱
耐食性が優れていると共に放電に対する耐消耗性の良い
ことが要求される。この要求を満たす材料として，前者
のごとくニッケルにクロム等を添加した高価なニッケル
基合金が従来より使用されてきた。また，近年，後者の
ごとく，耐消耗性に非常に優れた前記貴金属チップを発
火部に備えたものが製品化されるにあたっても，電極材
料としては，相変わらず耐熱耐食性に優れたニッケル基
合金が使用されている。上記貴金属チップは，中心電極
及び接地電極の発火部において，少なくともその一方に
溶接されている。上記のごとく，貴金属チップを上記発
火部の少なくとも一方に溶接したスパークプラグにおい
ては，耐熱耐食性と共に放電による耐消耗性にも非常に
優れている。2. Description of the Related Art Conventionally, in some spark plugs for internal combustion engines, nickel-base alloy is used as the electrode material of the center electrode and the ground electrode. And in the ignition part,
There are a type using only the above nickel-based alloy and a type using the nickel-based alloy as a base material and welding a noble metal tip made of platinum or a platinum alloy on the surface thereof. That is, the electrode of the spark plug that constantly discharges in the combustion chamber of the engine is required to have excellent heat resistance and corrosion resistance and good wear resistance to discharge. As a material satisfying this requirement, an expensive nickel-based alloy in which chromium or the like is added to nickel has been conventionally used as in the former case. Further, in recent years, even when the above-mentioned noble metal tip having excellent wear resistance in the ignition part is commercialized like the latter, a nickel-based alloy excellent in heat resistance and corrosion resistance is still used as an electrode material. Has been done. The noble metal tip is welded to at least one of the ignition parts of the center electrode and the ground electrode. As described above, in the spark plug in which the noble metal tip is welded to at least one of the ignition parts, the heat resistance and corrosion resistance as well as the wear resistance due to discharge are very excellent.
【０００３】[0003]
【解決しようとする課題】しかしながら，発火部に上記
貴金属チップを溶接したスパークプラグにおいては，次
の問題がある。即ち，電極材料を構成するニッケル基合
金と貴金属チップとの間においては，その線膨張係数に
大きな差がある。そのため，高温のエンジン中で長期間
使用していると，熱応力により，貴金属チップがニッケ
ル基合金の電極材料より，剥離脱落するというおそれが
ある。上記線膨張係数は，ニッケル基合金においては，
約１３×１０-6／℃，貴金属チップにおいては約９×１
０-6／℃である。[Problems to be Solved] However, the spark plug in which the above-mentioned precious metal tip is welded to the ignition part has the following problems. That is, there is a large difference in the coefficient of linear expansion between the nickel-based alloy that constitutes the electrode material and the noble metal tip. Therefore, when used for a long time in a high temperature engine, the noble metal tip may peel off from the nickel-based alloy electrode material due to thermal stress. The above linear expansion coefficient is
About 13 × 10 -6 / ℃, about 9 × 1 for precious metal tips
It is 0 -6 / ° C.
【０００４】そこで，ニッケル基合金と貴金属チップと
の線膨張係数の差に起因する熱応力を軽減すべく，特公
昭５９−４７４３６号公報に示されるごとく，ニッケル
基合金と貴金属チップとの溶接部に合金層を設ける提案
がなされている。また，特公平３−２２０３３号公報に
示されるごとく，ニッケル基合金と貴金属チップとの間
に，両者の間の線膨張係数を有する，別個の白金合金よ
りなる熱応力緩和層を設けることも提案されている。Therefore, in order to reduce the thermal stress due to the difference in linear expansion coefficient between the nickel-base alloy and the noble metal tip, as shown in Japanese Patent Publication No. 59-47436, the welded portion between the nickel-base alloy and the noble metal tip. It has been proposed to provide an alloy layer on the. Further, as disclosed in Japanese Patent Publication No. 3-22033, it is also proposed to provide a thermal stress relaxation layer made of a separate platinum alloy having a linear expansion coefficient between the nickel-based alloy and the noble metal tip. Has been done.
【０００５】しかし，前者の合金層を設ける方法におい
ては，ニッケル基合金よりなる電極材料の表面に貴金属
チップを溶接した後，両者の間に上記合金層を形成させ
る必要がある。そのため，上記溶接後において，高温の
加熱炉中でこれらを熱処理する必要があり，コスト高と
なる。また，後者の熱応力緩和層を設ける方法において
は，ニッケル基合金よりなる電極材料と上記貴金属チッ
プとの間に，熱応力緩和層用の白金合金材料を必要とす
る。そのため，２種類の白金合金を用いることとなり，
コスト高となる。本発明はかかる従来の問題点に鑑み，
電極材料が優れた耐熱耐食性を有し，電極材料と貴金属
チップとの間の熱応力を軽減でき，かつ製造容易な内燃
機関用スパークプラグを提供しようとするものである。However, in the former method of providing the alloy layer, it is necessary to weld the noble metal tip to the surface of the electrode material made of a nickel-based alloy and then form the alloy layer between the two. Therefore, it is necessary to heat-treat these in a high-temperature heating furnace after the above welding, which results in high cost. In the latter method of providing the thermal stress relaxation layer, a platinum alloy material for the thermal stress relaxation layer is required between the electrode material made of a nickel-based alloy and the noble metal tip. Therefore, two kinds of platinum alloys will be used,
High cost. In view of the above conventional problems, the present invention is
It is intended to provide a spark plug for an internal combustion engine, in which the electrode material has excellent heat and corrosion resistance, the thermal stress between the electrode material and the noble metal tip can be reduced, and the manufacturing is easy.
【０００６】[0006]
【課題の解決手段】本発明は，絶縁碍子と該絶縁碍子に
保持した中心電極と，上記絶縁碍子の外周に固定したハ
ウジングと，該ハウジングに設けられ上記中心電極と対
向させた接地電極とよりなり，かつ上記中心電極と接地
電極の少なくとも一方の電極材料にはその発火部に白金
又は白金合金よりなる貴金属チップを溶接してなる内燃
機関用スパークプラグにおいて，上記貴金属チップを溶
接すべき電極材料は，クロム８〜１８重量％を含有する
鉄合金により構成されていることを特徴とする内燃機関
用スパークプラグにある。本発明において最も注目すべ
きことは，中心電極及び接地電極の一方又は双方に上記
貴金属チップを溶接したスパークプラグにおいて，上記
貴金属チップが溶接される電極材料は上記鉄合金を用い
ることである。According to the present invention, there are provided an insulator, a center electrode held by the insulator, a housing fixed to the outer periphery of the insulator, and a ground electrode provided in the housing and facing the center electrode. In a spark plug for an internal combustion engine, in which at least one of the center electrode and the ground electrode is welded with a noble metal tip made of platinum or a platinum alloy at its ignition part, the electrode material to which the noble metal tip is to be welded Is a spark plug for an internal combustion engine, characterized in that it is made of an iron alloy containing 8 to 18% by weight of chromium. What is most noteworthy in the present invention is that in the spark plug in which the noble metal tip is welded to one or both of the center electrode and the ground electrode, the iron alloy is used as the electrode material to which the noble metal tip is welded.
【０００７】上記鉄合金は，クロム（Ｃｒ）が８〜１８
重量％と鉄（Ｆｅ）が残部とからなる基本組成を有す
る。Ｃｒが８重量％未満では，スパークプラグが用いら
れる内燃機関の高温腐食雰囲気中での使用に対して，酸
化抵抗が低く，耐熱耐食性が不充分である。一方，１８
重量％を越えると，中心電極や接地電極の形状に鉄合金
を成形，曲げ，切断，溶接する際の加工性が低下する。
また，Ｃｒが８〜１８重量％の場合には，電極材料の線
膨張係数が約１０〜１１×１０-6／℃であり，貴金属チ
ップの線膨張係数（約９×１０-6／℃）に近く，電極材
料と貴金属チップの間の熱応力が大幅に軽減される。The above iron alloy has a chromium (Cr) content of 8-18.
It has a basic composition of wt% and the balance iron (Fe). If the Cr content is less than 8% by weight, the oxidation resistance is low and the heat and corrosion resistance is insufficient for use in a high temperature corrosive atmosphere of an internal combustion engine in which a spark plug is used. On the other hand, 18
If it exceeds the weight%, the workability in forming, bending, cutting and welding the iron alloy into the shape of the center electrode and the ground electrode will be deteriorated.
When the Cr content is 8 to 18 wt%, the linear expansion coefficient of the electrode material is about 10 to 11 × 10 −6 / ° C., and the linear expansion coefficient of the noble metal tip (about 9 × 10 −6 / ° C.). , And the thermal stress between the electrode material and the noble metal tip is greatly reduced.
【０００８】また，上記鉄合金は，強度，耐酸化性等の
観点よりクロムの他に，一般に鉄合金中に含有させる，
炭素（Ｃ），マンガン（Ｍｎ），シリコン（Ｓｉ）を含
有させることが好ましい。上記Ｃは０．０５〜０．１８
重量％とすることが好ましい。上記Ｍｎは０．５〜１．
２重量％とすることが好ましい。また，上記Ｓｉは０．
６〜１．２重量％とすることが好ましい。Further, the above iron alloy is generally contained in the iron alloy in addition to chromium in terms of strength, oxidation resistance and the like.
It is preferable to contain carbon (C), manganese (Mn), and silicon (Si). The above C is 0.05 to 0.18
It is preferably set to wt%. The Mn is 0.5 to 1.
It is preferably 2% by weight. Further, the Si is 0.
It is preferably 6 to 1.2% by weight.
【０００９】また，貴金属チップを溶接すべき上記電極
材料は，Ｃｒ８〜１８重量％の他に，アルミニウム（Ａ
ｌ），ニッケル（Ｎｉ），モリブデン（Ｍｏ），銅（Ｃ
ｕ），チタン（Ｔｉ），ニオブ（Ｎｂ），ジルコニウム
（Ｚｒ）及びセレン（Ｓｅ）の中の１種以上からなる添
加物０．１〜５重量％を含有する鉄合金で構成すること
が好ましい。The electrode material to be welded with the noble metal tip is aluminum (A
l), nickel (Ni), molybdenum (Mo), copper (C
u), titanium (Ti), niobium (Nb), zirconium (Zr) and selenium (Se) It is preferable to be composed of an iron alloy containing 0.1 to 5% by weight of an additive. ..
【００１０】これらの添加物を，この範囲で添加した場
合には，電極材料の耐熱耐食性，加工性，強度が一層向
上すると共に電極材料と貴金属チップとの溶接性が更に
向上する。これら添加物を含有する鉄合金においても，
上記Ｃ，Ｍｎ，Ｓｉを上記範囲で含有していることが好
ましい。上記電極材料と貴金属チップとの溶接方法とし
ては，抵抗溶接等の方法がある。When these additives are added within this range, the heat resistance and corrosion resistance of the electrode material, the workability, and the strength are further improved, and the weldability between the electrode material and the noble metal tip is further improved. Even in iron alloys containing these additives,
It is preferable to contain the above C, Mn, and Si in the above range. As a method of welding the electrode material and the noble metal tip, there is a method such as resistance welding.
【００１１】また，本発明において，上記鉄合金は，貴
金属チップを溶接するための電極材料，即ち中心電極又
は接地電極の材料として用いるものである。それ故，貴
金属チップを溶接しない中心電極又は接地電極の電極材
料としては，従来と同様のニッケル基合金を用いること
もできる。例えば，中心電極の発火部には貴金属チップ
を溶接し，接地電極の発火部には貴金属チップを溶接し
ない場合には，中心電極の電極材料は本発明にかかる上
記鉄合金を用い，一方接地電極の電極材料は従来のニッ
ケル基合金を用いる。In the present invention, the iron alloy is used as an electrode material for welding the noble metal tip, that is, a material for the center electrode or the ground electrode. Therefore, as the electrode material of the center electrode or the ground electrode which does not weld the noble metal tip, the nickel-based alloy similar to the conventional one can be used. For example, when the noble metal tip is welded to the ignition part of the center electrode and the noble metal tip is not welded to the ignition part of the ground electrode, the electrode material of the center electrode is the iron alloy according to the present invention, while the ground electrode is used. A conventional nickel-based alloy is used as the electrode material.
【００１２】[0012]
【作用及び効果】本発明の内燃機関用スパークプラグに
おいては，貴金属チップを溶接すべき電極材料として，
８〜１８重量％のＣｒを含有する鉄合金を用いている。
そのため，電極材料の耐熱耐食性が高い。即ち，内燃機
関の高温腐食雰囲気中で用いられるスパークプラグにお
いては，中心電極，接地電極ともにその高温耐酸化性が
強く要求される。この点，本発明の電極材料は，Ｆｅを
主成分とするために高温下における酸化進行が懸念され
る。しかし，本発明の電極材料は８〜１８重量％のＣｒ
を含有しているため，Ｃｒの酸化物が電極表面を緻密に
覆い，電極材料の内部への酸化進行を阻止する。それ
故，耐熱耐食性に優れている。In the spark plug for an internal combustion engine of the present invention, the noble metal tip is used as the electrode material to be welded,
An iron alloy containing 8 to 18% by weight of Cr is used.
Therefore, the heat and corrosion resistance of the electrode material is high. That is, in a spark plug used in a high temperature corrosive atmosphere of an internal combustion engine, high temperature oxidation resistance is strongly required for both the center electrode and the ground electrode. In this respect, since the electrode material of the present invention contains Fe as a main component, there is a concern that oxidation will proceed at high temperatures. However, the electrode material of the present invention contains 8-18% by weight of Cr.
Since it contains Cr, the oxide of Cr densely covers the surface of the electrode and prevents the progress of oxidation into the electrode material. Therefore, it has excellent heat and corrosion resistance.
【００１３】また，８〜１８重量％のＣｒを含有する鉄
合金は，線膨張係数が約１０〜１１×１０-6／℃であ
り，貴金属チップの線膨張係数（約９×１０-6／℃）と
の差異は約１〜２×１０-6／℃程度と小さい。そのた
め，線膨張係数差に起因する熱応力の発生は，大幅に低
減され，電極材料と貴金属チップとの間に剥離が発生す
るおそれはない。また，従来のごとく，電極材料と貴金
属チップとの間に合金層を形成するための高温熱処理は
不要となる。また，熱応力緩和層形成のために２種類の
白金合金材料を準備する必要もない。それ故，スパーク
プラグの製造が容易で，コストも低下する。An iron alloy containing 8 to 18% by weight of Cr has a linear expansion coefficient of about 10 to 11 × 10 -6 / ° C., and a linear expansion coefficient of a noble metal tip (about 9 × 10 -6 / ° C.). C.) is as small as about 1 to 2 × 10 −6 / ° C. Therefore, the occurrence of thermal stress due to the difference in linear expansion coefficient is greatly reduced, and there is no risk of peeling between the electrode material and the noble metal tip. Further, unlike the conventional case, the high temperature heat treatment for forming the alloy layer between the electrode material and the noble metal tip is unnecessary. Further, it is not necessary to prepare two kinds of platinum alloy materials for forming the thermal stress relaxation layer. Therefore, the manufacture of the spark plug is easy and the cost is reduced.
【００１４】また，上記鉄合金に，更にＡｌ等の上記添
加物を添加した場合には，耐熱耐食性，加工性，強度が
一層向上し，また貴金属チップとの溶接性も向上する。
したがって，本発明によれば，電極材料が優れた耐熱耐
食性を有し，電極材料と貴金属チップとの間の熱応力を
軽減でき，かつ製造容易な内燃機関用スパークプラグを
提供することができる。When the above-mentioned additive such as Al is further added to the iron alloy, the heat and corrosion resistance, the workability and the strength are further improved, and the weldability with the noble metal tip is also improved.
Therefore, according to the present invention, it is possible to provide a spark plug for an internal combustion engine in which the electrode material has excellent heat resistance and corrosion resistance, the thermal stress between the electrode material and the noble metal tip can be reduced, and the manufacturing is easy.
【００１５】[0015]
【実施例】実施例１ 本発明の実施例にかかる内燃機関用スパークプラグにつ
き，図１及び図２を用いて説明する。本例のスパークプ
ラグ２は，絶縁碍子２０と，該絶縁碍子２０に保持した
本発明にかかる中心電極４と，絶縁碍子２０の外周に固
定したハウジング２５と，該ハウジング２５に設けられ
て，上記中心電極４との間にギャップ３０を設けて対向
させた本発明にかかる接地電極３とよりなる。Embodiment 1 A spark plug for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The spark plug 2 of this example is provided with an insulator 20, the center electrode 4 according to the present invention held by the insulator 20, a housing 25 fixed to the outer periphery of the insulator 20, and the housing 25. The ground electrode 3 according to the present invention is opposed to the center electrode 4 with a gap 30 provided therebetween.
【００１６】上記中心電極４の発火部には，白金合金よ
りなる貴金属チップ１を溶接している。また，上記接地
電極３の発火部にも，白金合金よりなる貴金属チップ１
を溶接している。そして，上記中心電極４及び接地電極
３の電極材料は，いずれもＣｒ８〜１８重量％を含有す
る鉄合金により構成されている。また，上記両電極材料
と貴金属チップ１とは，抵抗溶接により溶接されてい
る。A noble metal tip 1 made of a platinum alloy is welded to the ignition part of the center electrode 4. In addition, the noble metal tip 1 made of a platinum alloy is also provided on the ignition part of the ground electrode 3.
Are welding. The electrode materials of the center electrode 4 and the ground electrode 3 are both made of an iron alloy containing 8 to 18% by weight of Cr. Further, both the electrode materials and the noble metal tip 1 are welded by resistance welding.
【００１７】次に，上記絶縁碍子２０は高純度のアルミ
ナよりなり，リング状の気密パッキン２４及びリング２
３を介してハウジング２５の内孔にかしめ固定されてい
る。中心電極４は，その下方先端部を，絶縁碍子２０の
下方に突出させて該絶縁碍子２０に保持してある。ま
た，絶縁碍子２０の軸孔２２には，上部に端子４２１を
有する中軸４２が挿入され，導電性のガラスシール材４
４により，上記中心電極４と一体的に加熱融着してあ
る。また，接地電極３はハウジング２５の環状端面２５
１に接合されている。Next, the insulator 20 is made of high-purity alumina and has a ring-shaped hermetic packing 24 and a ring 2.
It is fixed by caulking to the inner hole of the housing 25 through 3. The center electrode 4 has its lower tip portion projected below the insulator 20 and held by the insulator 20. In addition, the inner shaft 42 having the terminal 421 in the upper portion is inserted into the shaft hole 22 of the insulator 20, and the conductive glass sealing material 4 is provided.
4, the central electrode 4 and the central electrode 4 are integrally fused by heating. Further, the ground electrode 3 is an annular end surface 25 of the housing 25.
It is joined to 1.
【００１８】実施例２ 次に，実施例１に示したスパークプラグにつき，中心電
極４，接地電極３に用いた電極材料における，鉄合金の
組成を種々に変えて，評価試験を行い，その結果を表１
に示した。即ち，電極材料としては，クロム（Ｃｒ）を
０〜２４重量％，カーボン（Ｃ）を０．１０〜０．１５
重量％，マンガン（Ｍｎ）を０．７〜１．０重量％，珪
素（Ｓｉ）を０．８〜１．０重量％，残部が鉄（Ｆｅ）
よりなる鉄合金を用いた。そして，エンジンでの各材料
の酸化試験，エンジンでの貴金属チップの接合の信頼性
試験，更に電極材料の中心電極及び接地電極への加工性
の検討を実施した。上記酸化試験は電極材料の耐熱耐食
性に関するものである。以下，その詳細について述べ
る。Example 2 Next, with respect to the spark plug shown in Example 1, an evaluation test was conducted by changing the composition of the iron alloy in the electrode material used for the center electrode 4 and the ground electrode 3 variously. Table 1
It was shown to. That is, as an electrode material, 0 to 24% by weight of chromium (Cr) and 0.10 to 0.15 of carbon (C) are used.
Wt%, manganese (Mn) 0.7-1.0 wt%, silicon (Si) 0.8-1.0 wt%, balance iron (Fe)
Was used. Then, we conducted an oxidation test of each material in the engine, a reliability test of joining the noble metal tip in the engine, and a study of the workability of the electrode material for the center electrode and the ground electrode. The above-mentioned oxidation test relates to the heat and corrosion resistance of the electrode material. The details will be described below.
【００１９】エンジン試験は，４サイクル，６気筒，２
０００ｃｃのエンジンを用い，アイドリング１分間とフ
ルスロットル１分間の繰り返しを１００時間実施した。
電極材料の酸化試験は，接地電極３に関して，図３に例
示するように，上記エンジン試験後における接地電極３
の内部への酸化物３１１の生成深さを測定し，同時に評
価したニッケル基合金（従来の電極材料）の結果と比較
した。The engine test is 4 cycles, 6 cylinders, 2
Using a 000 cc engine, idling for 1 minute and full throttle for 1 minute were repeated for 100 hours.
As shown in FIG. 3, the oxidation test of the electrode material is performed on the ground electrode 3 as shown in FIG.
The formation depth of the oxide 311 inside the was measured and compared with the result of the nickel-based alloy (conventional electrode material) evaluated at the same time.
【００２０】貴金属チップ１の接合の信頼性は，接地電
極３に関して図４に例示するように，上記エンジン試験
後における貴金属チップ１と接地電極３との接合面への
酸化物３１２の生成深さを測定し，同時に評価したニッ
ケル基合金の結果と比較した。加工性については電極材
料を中心電極４と接地電極３の形状に加工するに当たっ
て必要な，成形，曲げ，溶接等の加工性につき評価し，
ニッケル基合金と比較した。その結果を表１に示す。As shown in FIG. 4 for the ground electrode 3, the reliability of the bonding of the noble metal chip 1 is determined by the depth of formation of the oxide 312 on the bonding surface between the noble metal chip 1 and the ground electrode 3 after the engine test. Was measured and compared with the results of the nickel-based alloy evaluated at the same time. Regarding workability, the workability of forming, bending, welding, etc. necessary for processing the electrode material into the shapes of the center electrode 4 and the ground electrode 3 was evaluated,
Compared to nickel-based alloys. The results are shown in Table 1.
【００２１】表１より知られるごとく，電極材料におけ
る酸化物の生成深さ（図３参照）は，Ｃｒが８重量％以
上の場合には，従来のニッケル基合金と同等となり，耐
熱耐食性に優れていることが分かる。また，電極材料と
貴金属チップとの接合面における酸化物の生成深さ（図
４参照）は，Ｃｒが６重量％以上の場合には，極めて少
なく，従来のニッケル基合金よりも優れた接合性を示し
ている。As is known from Table 1, the depth of oxide formation in the electrode material (see FIG. 3) is equivalent to that of the conventional nickel-base alloy when Cr is 8% by weight or more, and the heat resistance and corrosion resistance are excellent. I understand that. In addition, the depth of oxide formation at the joining surface between the electrode material and the noble metal tip (see Fig. 4) was extremely small when Cr was 6 wt% or more, and the joining property was superior to that of conventional nickel-based alloys. Is shown.
【００２２】また，電極材料の加工性に関しては，Ｃｒ
が１６重量％以下の場合は，ニッケル基合金と同等であ
り，Ｃｒが１８重量％の場合にはニッケル基合金に若干
劣る。しかし，Ｃｒが２０重量％を越えると加工性がか
なり劣る。また，Ｃｒ８〜１８重量％を含有する電極材
料は，前記のごとくその線膨張係数が貴金属チップのそ
れと近似しており，熱応力に基づく剥離のおそれはな
い。以上より，鉄合金中に含有させるＣｒは，８〜１８
重量％が適切であることが分かる。Regarding workability of the electrode material, Cr
Is less than 16% by weight, it is equivalent to the nickel-based alloy, and when Cr is 18% by weight, it is slightly inferior to the nickel-based alloy. However, if Cr exceeds 20% by weight, workability is considerably deteriorated. Further, the electrode material containing 8 to 18% by weight of Cr has a linear expansion coefficient similar to that of the noble metal tip as described above, and there is no risk of peeling due to thermal stress. From the above, the amount of Cr contained in the iron alloy is 8 to 18
It turns out that weight percent is appropriate.
【００２３】[0023]
【表１】 [Table 1]
【００２４】実施例３ 本例は，実施例２に示した電極材料の中，試料Ｎｏ５
（Ｃｒ含量８重量％）を基準として，これに前記添加物
を添付した鉄合金を用い，実施例２と同様の評価試験を
行った例である。その結果を表２に示す。上記添加物と
しては，表２に示す８種類の中の１種又は２種以上を
０．１〜５重量％添加した。各電極材料は，Ｃｒ８重量
％，Ｃ０．１４重量％，Ｍｎ及びＳｉ０．９重量％，上
記添加物０．１〜５重量％及び残部Ｆｅからなる。Example 3 In this example, sample No. 5 among the electrode materials shown in Example 2 was used.
This is an example in which the same evaluation test as in Example 2 was performed using an iron alloy with the above-mentioned additives added thereto based on (Cr content 8% by weight). The results are shown in Table 2. As the above additive, 0.1 to 5% by weight of one kind or two or more kinds out of the eight kinds shown in Table 2 was added. Each electrode material is composed of 8% by weight of Cr, 0.14% by weight of C, 0.9% by weight of Mn and Si, 0.1 to 5% by weight of the above additive, and the balance Fe.
【００２５】表２より知られるごとく，上記添加物を含
有させることにより，電極材料における酸化物の生成深
さが，試料Ｎｏ５の場合よりも少なくなり，耐熱耐食性
が一層向上することが分かる。また，加工性に関して
は，試料Ｎｏ５よりも若干劣るものもあるが，Ｎｏ５と
同等又はそれより優れるものが多い。このように，上記
添加物の添加により，耐熱耐食性，加工性ともに優れた
電極材料が得られる。As can be seen from Table 2, the inclusion of the above-mentioned additive results in a smaller oxide formation depth in the electrode material than in the case of Sample No. 5 and further improves heat and corrosion resistance. Further, regarding workability, although some are slightly inferior to Sample No. 5, many are equivalent to or superior to No. 5. Thus, the addition of the above-mentioned additives makes it possible to obtain an electrode material having excellent heat resistance, corrosion resistance, and workability.
【００２６】[0026]
【表２】 [Table 2]
【図１】実施例１にかかる内燃機関用スパークプラグの
要部拡大図。FIG. 1 is an enlarged view of a main part of a spark plug for an internal combustion engine according to a first embodiment.
【図２】実施例１にかかる内燃機関用スパークプラグの
一部断面図。FIG. 2 is a partial sectional view of a spark plug for an internal combustion engine according to a first embodiment.
【図３】実施例２の評価試験における，電極材料の酸化
状態を示す説明図。FIG. 3 is an explanatory diagram showing an oxidized state of an electrode material in the evaluation test of Example 2.
【図４】実施例２の評価試験における，電極材料と貴金
属チップの接合部の酸化状態を示す説明図。FIG. 4 is an explanatory diagram showing an oxidized state of a joint portion between an electrode material and a noble metal tip in the evaluation test of Example 2.
【符号の説明】 １．．．貴金属チップ， ２０．．．絶縁碍子， ２５．．．ハウジング， ３．．．接地電極， ３１１，３１２．．．酸化物， ４．．．中心電極，[Explanation of symbols] 1. ． ． Noble metal tip, 20. ． ． Insulator, 25. ． ． Housing, 3. ． ． Ground electrode, 311, 312. ． ． Oxides, 4. ． ． Center electrode,
Claims (2)
極と，上記絶縁碍子の外周に固定したハウジングと，該
ハウジングに設けられ上記中心電極と対向させた接地電
極とよりなり，かつ上記中心電極と接地電極の少なくと
も一方の電極材料にはその発火部に白金又は白金合金よ
りなる貴金属チップを溶接してなる内燃機関用スパーク
プラグにおいて， 上記貴金属チップを溶接すべき電極材料は，クロム８〜
１８重量％を含有する鉄合金により構成されていること
を特徴とする内燃機関用スパークプラグ。1. An insulator, a center electrode held by the insulator, a housing fixed to the outer periphery of the insulator, a ground electrode provided in the housing and facing the center electrode, and the center. In a spark plug for an internal combustion engine, in which at least one of an electrode and a ground electrode is welded with a noble metal tip made of platinum or a platinum alloy at its ignition portion, the electrode material to which the noble metal tip is to be welded is chromium 8
A spark plug for an internal combustion engine, which is composed of an iron alloy containing 18% by weight.
すべき電極材料は，クロム８〜１８重量％，アルミニウ
ム，ニッケル，モリブデン，銅，チタン，ニオブ，ジル
コニウム及びセレンの中の１種以上からなる添加物０．
１〜５重量％を含有する鉄合金により構成されているこ
とを特徴とする内燃機関用スパークプラグ。2. The electrode material for welding a noble metal tip according to claim 1, comprising 8 to 18% by weight of chromium, one or more of aluminum, nickel, molybdenum, copper, titanium, niobium, zirconium and selenium. Additive 0.
A spark plug for an internal combustion engine, which is composed of an iron alloy containing 1 to 5% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03147692A JP3196286B2 (en) | 1992-01-21 | 1992-01-21 | Spark plug for internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03147692A JP3196286B2 (en) | 1992-01-21 | 1992-01-21 | Spark plug for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05198349A true JPH05198349A (en) | 1993-08-06 |
| JP3196286B2 JP3196286B2 (en) | 2001-08-06 |
Family
ID=12332320
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03147692A Expired - Fee Related JP3196286B2 (en) | 1992-01-21 | 1992-01-21 | Spark plug for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3196286B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6187201B1 (en) | 1993-08-10 | 2001-02-13 | Nomura Micro Science Co., Ltd. | System for producing ultra-pure water |
| US6677698B2 (en) * | 2000-12-15 | 2004-01-13 | Delphi Technologies, Inc. | Spark plug copper core alloy |
| JP2004165168A (en) * | 1999-06-25 | 2004-06-10 | Ngk Spark Plug Co Ltd | Spark plug |
| WO2011008801A3 (en) * | 2009-07-15 | 2011-04-07 | Federal-Mogul Ignition Company | Spark plug including high temperature performance electrode |
-
1992
- 1992-01-21 JP JP03147692A patent/JP3196286B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6187201B1 (en) | 1993-08-10 | 2001-02-13 | Nomura Micro Science Co., Ltd. | System for producing ultra-pure water |
| JP2004165168A (en) * | 1999-06-25 | 2004-06-10 | Ngk Spark Plug Co Ltd | Spark plug |
| US6677698B2 (en) * | 2000-12-15 | 2004-01-13 | Delphi Technologies, Inc. | Spark plug copper core alloy |
| WO2011008801A3 (en) * | 2009-07-15 | 2011-04-07 | Federal-Mogul Ignition Company | Spark plug including high temperature performance electrode |
| US8575829B2 (en) | 2009-07-15 | 2013-11-05 | Federal-Mogul Ignition Company | Spark plug including high temperature performance electrode |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3196286B2 (en) | 2001-08-06 |
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