JP3461670B2 - Spark plug and its manufacturing method - Google Patents
Spark plug and its manufacturing methodInfo
- Publication number
- JP3461670B2 JP3461670B2 JP33511996A JP33511996A JP3461670B2 JP 3461670 B2 JP3461670 B2 JP 3461670B2 JP 33511996 A JP33511996 A JP 33511996A JP 33511996 A JP33511996 A JP 33511996A JP 3461670 B2 JP3461670 B2 JP 3461670B2
- Authority
- JP
- Japan
- Prior art keywords
- center electrode
- spark plug
- alloy
- metal shell
- insulator
- 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
- 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
-
- 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
Description
【０００１】[0001]
【発明の属する技術分野】本発明は内燃機関に使用され
るスパークプラグに関する。TECHNICAL FIELD The present invention relates to a spark plug used in an internal combustion engine.
【０００２】[0002]
【従来の技術】従来、自動車エンジン等の内燃機関用の
スパークプラグとして、耐火花消耗性向上のために、電
極の先端にＰｔ（白金）合金のチップを溶接して発火部
を形成したものが使用されているが、白金は高価である
ためチップ材料として安価なＩｒ（イリジウム）を使用
する提案がなされている。2. Description of the Related Art Heretofore, as a spark plug for an internal combustion engine such as an automobile engine, a spark plug is formed by welding a Pt (platinum) alloy tip to the tip of an electrode in order to improve spark wear resistance. Although used, platinum has been proposed because it uses inexpensive Ir (iridium) as a chip material because platinum is expensive.
【０００３】[0003]
【発明が解決しようとする課題】上述のプラグにおいて
発火部をＩｒで構成した場合、Ｉｒは９００〜１０００
℃の高温域において酸化・揮発しやすい性質を有してい
るため、そのまま電極発火部に使用すると、火花消耗よ
りも酸化・揮発による消耗が問題となる欠点がある。従
って、市街地走行のような温度の低い条件であれば耐久
性はよいが、高速連続運転の場合には、耐久性が極端に
低下してしまう問題があった。When the ignition part is made of Ir in the above-mentioned plug, Ir is 900 to 1000.
Since it has a property of being easily oxidized and volatilized in a high temperature range of ℃, if it is used as it is in the electrode ignition part, there is a drawback that the consumption by oxidation and volatilization becomes a problem rather than the spark consumption. Therefore, the durability is good under the condition of low temperature such as city driving, but there is a problem that the durability is extremely lowered in the case of high speed continuous operation.
【０００４】本発明は、発火部がＩｒを主体に構成され
つつも、高温でのＩｒ成分の酸化・揮発による消耗が起
こりにくく、ひいては市街地走行においても、高速走行
においても耐久性に優れたスパークプラグを提供するこ
とにある。According to the present invention, although the ignition part is mainly composed of Ir, the spark is excellent in durability even in city driving and high speed driving because the Ir component is hardly consumed by oxidation and volatilization at high temperature. To provide a plug.
【０００５】[0005]
【課題を解決するための手段及び作用・効果】上述の課
題を解決するために本発明のスパークプラグは、中心電
極と、その中心電極の外側に設けられた絶縁体と、前記
絶縁体の外側に設けられた主体金具と、その主体金具に
一端が結合されるとともに他端側が側方に曲げ返され
て、その側面が前記中心電極の先端部と対向するように
配置された接地電極と、前記中心電極に固着されて火花
放電ギャップを形成する発火部とを備え、前記中心電極
の先端面に、Ｉｒを主体としてＲｈを７〜２５重量％の
範囲で含有する組成の合金からなるチップであって、前
記組成の溶解合金を７００℃以上の温度で熱間圧延又は
熱間鍛造により線状あるいはロッド状に加工した後、こ
れを長さ方向に所定長に切断して製造されたものを重ね
合わせ、または、前記組成の溶解合金を７００℃以上の
温度で熱間圧延により板状に加工し、さらにその板材を
熱間打抜き加工により所定の形状に打ち抜いて製造され
たものを重ね合わせ、その接合面外縁部に沿って、前記
チップと前記中心電極とにまたがる溶接部を形成するこ
とにより、Ｉｒを主体としてＲｈを７〜２５重量％の範
囲で含有する組成の合金からなる発火部を形成したこと
を特徴とする。In order to solve the above-mentioned problems, the spark plug of the present invention has a central electric power source.
A pole, an insulator provided outside the center electrode thereof, and
The metal shell provided on the outside of the insulator and the metal shell
One end is joined and the other end is bent back to the side.
So that its side faces the tip of the center electrode.
Sparks that are fixed to the ground electrode and the center electrode that are placed
And a firing portion forming a discharge gap, the center electrode
7 to 25 wt% of Rh, mainly Ir, on the tip surface of
A chip made of an alloy having a composition contained in the range of
Hot-rolling a molten alloy of the above composition at a temperature of 700 ° C or higher or
After processing into a linear or rod shape by hot forging,
Stacked by cutting it into a predetermined length in the length direction
Or a molten alloy of the above composition at 700 ° C or higher
Hot rolled at a temperature to form a plate, and then
Manufactured by punching into a predetermined shape by hot stamping
Are piled up, and along the outer edge of the joint surface,
Forming a weld that extends over the tip and the center electrode
As a result, Rh is mainly contained in the range of 7 to 25% by weight.
It is characterized in that an ignition part made of an alloy having a composition contained in the enclosure is formed .
【０００６】本発明者は、火花放電ギャップを形成する
発火部を、Ｉｒを主体として上記範囲のＲｈを含有する
合金で構成することで、高温でのＩｒ成分の酸化・揮発
による消耗が効果的に抑制され、ひいては耐久性に優れ
たスパークプラグが実現されることを見い出したのであ
る。The present inventor constructs the ignition part forming the spark discharge gap from an alloy containing Ir as a main component and Rh in the above range, so that the Ir component is effectively consumed by oxidation and volatilization at high temperatures. It was found that a spark plug that is suppressed by the above, and eventually has excellent durability is realized.
【０００７】なお、上記発火部は、表記組成の金属から
なるチップを、接地電極及び／又は中心電極に対し溶接
により接合して形成することができる。この場合、本明
細書でいう「発火部」とは、接合されたチップのうち、
溶接による組成変動の影響を受けていない部分（例え
ば、溶接により接地電極ないし中心電極の材料と合金化
した部分を除く残余の部分）を指すものとする。The ignition part can be formed by welding a tip made of a metal having a notational composition to the ground electrode and / or the center electrode by welding. In this case, the term "firing part" used in the present specification refers to, among the joined chips,
It refers to a portion that is not affected by the composition fluctuation due to welding (for example, the remaining portion excluding the portion alloyed with the material of the ground electrode or the center electrode by welding).
【０００８】上記合金中のＲｈの含有量が７重量％未満
になるとＩｒの酸化・揮発の抑制効果が不十分となり、
発火部が消耗しやすくなるためプラグの耐久性が低下す
る。この場合、発火部の消耗が起きる場所としては、中
心電極及び／又は接地電極に溶接されたチップの先端面
部分が第一に挙げられるが、Ｒｈ含有量が減少するとチ
ップの側面部でも消耗が進行することがある。このよう
な状況になると、火花放電のためのチップの通電断面積
が減少する結果、チップの先端面部に電界が集中しやす
くなり、消耗が加速度的に進行してプラグの寿命が急速
に尽きてしまうことにもつながる。従って、Ｒｈの含有
量の調整は、チップの先端面部だけでなく、側面部にお
ける消耗もなるべく生じにくい範囲を選定することが望
ましいといえる。さらに、その組成の溶解合金を７００
℃以上の温度で熱間圧延により板状に加工し、その板材
を熱間打抜き加工により所定の形状に打ち抜いてチップ
を形成したり、あるいは溶解合金を熱間圧延又は熱間鍛
造により線状あるいはロッド状に加工した後、これを長
さ方向に所定長に切断してチップを形成したりすること
ができる。チップ材質の主成分であるＩｒは単体金属と
しては延性あるいは展性に乏しいが、Ｒｈを添加するこ
とでその加工性が改善され、例えば圧延ないし鍛造によ
る板材、ロッドあるいは線材等への加工がＲｈを添加し
ない場合と比較して行いやすくなる。具体的には、圧延
ないし鍛造時に合金素材にクラック等の欠陥が生じにく
くなり、ひいてはチップの製造効率及び材料歩留まりを
向上させることができる。一方、Ｒｈの含有量が２５重
量％以上になると合金の融点が低下し、プラグの耐久性
が同様に低下する。以上のことから、Ｒｈの含有量は前
述の範囲で調整するのがよく、望ましくは１５〜２５重
量％、最も望ましくは１８〜２２重量％の範囲で調整す
るのがよい。When the content of Rh in the above alloy is less than 7 % by weight, the effect of suppressing the oxidation and volatilization of Ir becomes insufficient,
Since the ignition part is easily worn, the durability of the plug is reduced. In this case, the tip surface portion of the tip welded to the center electrode and / or the ground electrode is the first place where the ignition portion is consumed. However, when the Rh content is reduced, the side surface portion of the tip is also consumed. It may progress. In such a situation, the electric current cross-sectional area of the tip for spark discharge is reduced, and as a result, the electric field tends to concentrate on the tip end surface of the tip, wear is accelerated and the life of the plug is rapidly exhausted. It also leads to being lost. Therefore, it can be said that it is desirable to adjust the content of Rh in a range in which not only the tip surface portion of the chip but also the side surface portion is less likely to be consumed. In addition, the molten alloy of that composition is 700
Hot rolled at a temperature above ℃
Is punched into a predetermined shape by hot punching
Forming or forming a molten alloy by hot rolling or hot forging
After processing into a linear or rod shape by manufacturing,
To form a chip by cutting it into a predetermined length in the vertical direction
You can Ir, which is the main component of the chip material, is a single metal
Is poor in ductility or malleability, but adding Rh
The workability is improved with and, for example, by rolling or forging.
Rh is added to the plate, rod, wire, etc.
It will be easier to do compared to the case without. Specifically, rolling
Or cracks and other defects are unlikely to occur in the alloy material during forging
The chip manufacturing efficiency and material yield.
Can be improved. On the other hand, when the content of Rh is 25 % by weight or more, the melting point of the alloy is lowered and the durability of the plug is similarly lowered. From the above, the content of Rh is preferably adjusted within the above range, preferably 15 to 25% by weight, and most preferably 18 to 22% by weight.
【０００９】[0009]
【発明の実施の形態】以下、本発明のいくつかの実施の
形態を図面を用いて説明する。図１に示す本発明の一例
たるスパークプラグ１００は、筒状の主体金具１、先端
部２１が突出するようにその主体金具１の内側に嵌め込
まれた絶縁体２、先端に形成された発火部３１を突出さ
せた状態で絶縁体２の内側に設けられた中心電極３、及
び主体金具１に一端が溶接等により結合されるとともに
他端側が側方に曲げ返されて、その側面が中心電極３の
先端部と対向するように配置された接地電極４等を備え
ている。また、接地電極４には上記発火部３１に対向す
る発火部３２が形成されており、それら発火部３１と、
対向する発火部３２との間の隙間が火花放電ギャップｇ
とされている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. A spark plug 100 as an example of the present invention shown in FIG. 1 includes a tubular metallic shell 1, an insulator 2 fitted inside the metallic shell 1 so that a tip portion 21 projects, and an ignition portion formed at the tip. One end is joined to the center electrode 3 provided inside the insulator 2 and the metal shell 1 in a state in which 31 is projected, and the other end side is bent back to the side, and the side surface is the center electrode. The ground electrode 4 and the like are provided so as to face the tip portion of 3. In addition, the ground electrode 4 is formed with a firing portion 32 facing the firing portion 31, and these firing portions 31 and
The spark discharge gap g is the gap between the opposing firing parts 32.
It is said that.
【００１０】絶縁体２は、例えばアルミナあるいは窒化
アルミニウム等のセラミック焼結体により構成され、そ
の内部には自身の軸方向に沿って中心電極３を嵌め込む
ための孔部６を有している。また、主体金具１は、低炭
素鋼等の金属により円筒状に形成されており、スパーク
プラグ１００のハウジングを構成するとともに、その外
周面には、プラグ１００を図示しないエンジンブロック
に取り付けるためのねじ部７が形成されている。The insulator 2 is made of, for example, a ceramic sintered body such as alumina or aluminum nitride, and has a hole portion 6 for fitting the center electrode 3 therein along its axial direction. . The metal shell 1 is formed of a metal such as low carbon steel into a cylindrical shape, constitutes a housing of the spark plug 100, and has a screw for attaching the plug 100 to an engine block (not shown) on the outer peripheral surface thereof. The part 7 is formed.
【００１１】次に、中心電極３及び接地電極４の本体部
３ａ及び４ａはＮｉ合金等で構成されている。一方、上
記発火部３１及び対向する発火部３２は、Ｉｒを主体と
し、Ｒｈを３〜５０重量％（５０重量％を含まず）の範
囲で含有する合金により構成される。なお、合金中のＲ
ｈの含有量は、望ましくは７〜３０重量％、より望まし
くは１５〜２５重量％、最も望ましくは１８〜２２重量
％の範囲で調整される。Next, the main body portions 3a and 4a of the center electrode 3 and the ground electrode 4 are made of Ni alloy or the like. On the other hand, the ignition part 31 and the opposing ignition part 32 are composed of an alloy mainly containing Ir and containing Rh in the range of 3 to 50% by weight (not including 50% by weight). In addition, R in the alloy
The content of h is preferably adjusted in the range of 7 to 30% by weight, more preferably 15 to 25% by weight, and most preferably 18 to 22% by weight.
【００１２】図２に示すように、中心電極３の本体部３
ａは先端側が縮径されるとともにその先端面が平坦に構
成され、ここに上記発火部を構成する合金組成からなる
円板状のチップを重ね合わせ、さらにその接合面外縁部
に沿ってレーザー溶接、電子ビーム溶接、抵抗溶接等に
より溶接部Ｗを形成してこれを固着することにより発火
部３１が形成される。また、対向する発火部３２は、発
火部３１に対応する位置において接地電極４にチップを
位置合わせし、その接合面外縁部に沿って同様に溶接部
Ｗを形成してこれを固着することにより形成される。な
お、これらチップは、例えば表記組成となるように各合
金成分を配合・溶解することにより得られる溶解材、又
は合金粉末あるいは所定比率で配合された金属単体成分
粉末を成形・焼結することにより得られる焼結材により
構成することができる。As shown in FIG. 2, the main body 3 of the center electrode 3 is formed.
In a, the tip side is reduced in diameter and the tip surface is made flat, and a disk-shaped tip made of an alloy composition that constitutes the ignition part is superposed on the tip side, and laser welding is further performed along the outer edge of the joint surface. The ignition portion 31 is formed by forming the welded portion W by electron beam welding, resistance welding or the like and fixing the welded portion W. Further, in the opposing firing portion 32, the tip is aligned with the ground electrode 4 at a position corresponding to the firing portion 31, and a welding portion W is similarly formed along the outer edge portion of the joint surface to fix the tip. It is formed. In addition, these chips are prepared by, for example, melting / melting material obtained by blending / melting each alloy component so as to have a notational composition, or alloy powder or metal simple substance component powder blended in a predetermined ratio by molding / sintering. It can be composed of the obtained sintered material.
【００１３】例えば、チップを溶解合金で構成する場
合、該溶解合金素材に対し圧延、鍛造、引き抜き、切
削、切断及び打抜きの少なくともいずれかの工程を含む
加工を施すことにより所定のチップ形状を得ることがで
きる。ここで、圧延、鍛造、あるいは打抜き等の加工
は、合金を所定の温度に昇温して行うことができる（い
わゆる熱間あるいは温間加工）。その加工温度は合金組
成にもよるが、例えば７００℃以上とするのがよい。For example, when the chip is made of a molten alloy, a predetermined chip shape is obtained by subjecting the molten alloy material to at least one of the steps of rolling, forging, drawing, cutting, cutting and punching. be able to. Here, processing such as rolling, forging, or punching can be performed by raising the temperature of the alloy to a predetermined temperature (so-called hot or warm working). The processing temperature depends on the alloy composition, but is preferably 700 ° C. or higher.
【００１４】より具体的には、溶解合金を熱間圧延によ
り板状に加工し、さらにその板材を熱間打抜き加工によ
り所定の形状に打ち抜いてチップを形成する方法、ある
いは溶解合金を熱間圧延又は熱間鍛造により線状あるい
はロッド状に加工した後、これを長さ方向に所定長に切
断してチップを形成する方法等が採用できる。ここで、
チップ材質の主成分であるＩｒは単体金属としては延性
あるいは展性に乏しいが、Ｒｈを添加することでその加
工性が改善され、例えば圧延ないし鍛造による板材、ロ
ッドあるいは線材等への加工がＲｈを添加しない場合と
比較して行いやすくなる。具体的には、圧延ないし鍛造
時に合金素材にクラック等の欠陥が生じにくくなり、ひ
いてはチップの製造効率及び材料歩留まりを向上させる
ことができる。なお、合金素材の加工性は、Ｒｈの添加
量が増大するほど良好になる。More specifically, the molten alloy is processed into a plate shape by hot rolling, and the plate material is further punched into a predetermined shape by hot punching to form chips, or the molten alloy is hot rolled. Alternatively, it is possible to employ a method in which a wire or rod is processed by hot forging and then cut into a predetermined length in the length direction to form a chip. here,
Ir, which is the main component of the chip material, is poor in ductility or malleability as a simple metal, but its workability is improved by adding Rh. It becomes easier to perform compared to the case where is not added. Specifically, defects such as cracks are less likely to occur in the alloy material during rolling or forging, which in turn can improve chip manufacturing efficiency and material yield. The workability of the alloy material becomes better as the amount of Rh added increases.
【００１５】発火部３１及び対向する発火部３２のいず
れか一方を省略する構成としてもよい。この場合には、
発火部３１又は対向する発火部３２及び接地電極４又は
中心電極３との間で火花放電ギャップｇが形成される。It is also possible to omit either one of the ignition part 31 and the opposing ignition part 32. In this case,
A spark discharge gap g is formed between the ignition part 31 or the opposing ignition part 32 and the ground electrode 4 or the center electrode 3.
【００１６】以下、スパークプラグ１００の作用につい
て説明する。すなわち、スパークプラグ１００は、その
ねじ部７においてエンジンブロックに取り付けられ、燃
焼室に供給される混合気への着火源として使用される。
ここで、その火花放電ギャップｇを形成する発火部３１
及び対向する発火部３２が前述の合金で構成されること
で、Ｉｒの酸化・揮発による発火部の消耗が抑制される
ので、長期に渡って火花放電ギャップｇが拡大せず、プ
ラグ１００の寿命を伸ばすことができる。The operation of the spark plug 100 will be described below. That is, the spark plug 100 is attached to the engine block at the screw portion 7 thereof and is used as an ignition source for the air-fuel mixture supplied to the combustion chamber.
Here, the ignition part 31 forming the spark discharge gap g.
Also, since the opposing ignition part 32 is made of the above alloy, the consumption of the ignition part due to the oxidation and volatilization of Ir is suppressed, so that the spark discharge gap g does not expand for a long period of time, and the life of the plug 100 is reduced. Can be extended.
【００１７】[0017]
（実施例１）所定量のＩｒとＲｈを配合・溶解すること
により、Ｒｈを０〜６０重量％の各種比率で含有し残部
が実質的にＩｒで構成された合金（ただし、Ｒｈ＝０及
び６０重量％は比較例）を用意し、これを熱間圧延によ
り板材に加工し、さらに該板材から放電加工により直径
０．７mm、厚さ０．５mmの円板状のチップを切り出し
た。なお、比較例として、Ｐｔ−１３重量％Ｉｒ溶解合
金を用いたチップも作製した。それらチップを用いて、
図１に示すスパークプラグ１００の発火部３１及び対向
する発火部３２を形成するとともに（火花放電ギャップ
ｇの幅１．１mm）、各プラグの性能試験を以下の条件に
て行った。
条件Ａ（連続高速運転を想定）：６気筒ガソリンエンジ
ン（排気量３０００cc）にそれらプラグを取り付け、ス
ロットル全開状態、エンジン回転数６０００ｒｐｍにて
３００時間連続運転し（中心電極温度約９００℃）、運
転終了後のプラグの火花放電ギャップｇの拡大量を測定
した。図３は、その結果を、合金中のＲｈの含有量と火
花放電ギャップ増加量との関係で示したものである。
条件Ｂ（市街地運転を想定）：４気筒ガソリンエンジン
（排気量２０００cc）にそれらプラグを取り付け、アイ
ドリング１分→エンジン回転数３５００ｒｐｍ、全開状
態で３０分→エンジン回転数２０００ｒｐｍ、半開状態
で２０分を１サイクルとして、１０００時間運転し（中
心電極温度約７８０℃）、運転終了後のプラグの火花放
電ギャップｇの拡大量を測定した。図４は、その結果
を、合金中のＲｈの含有量と火花放電ギャップ増加量と
の関係で示したものである。(Example 1) By mixing and dissolving predetermined amounts of Ir and Rh, an alloy containing Rh in various ratios of 0 to 60% by weight and the balance being substantially Ir (provided that Rh = 0 and 60% by weight was prepared as a comparative example, and this was hot-rolled into a plate material, and a disk-shaped chip having a diameter of 0.7 mm and a thickness of 0.5 mm was cut out from the plate material by electric discharge machining. As a comparative example, a chip using a Pt-13 wt% Ir melting alloy was also manufactured. With those chips,
While forming the ignition part 31 and the opposed ignition part 32 of the spark plug 100 shown in FIG. 1 (width of the spark discharge gap g: 1.1 mm), the performance test of each plug was performed under the following conditions. Condition A (assuming continuous high-speed operation): Attach these plugs to a 6-cylinder gasoline engine (displacement 3000cc), fully open the throttle, and continuously operate for 300 hours at an engine speed of 6000rpm (center electrode temperature of about 900 ° C). The amount of expansion of the spark discharge gap g of the plug after completion was measured. FIG. 3 shows the result in relation to the content of Rh in the alloy and the increase amount of the spark discharge gap. Condition B (assuming urban driving): Attaching these plugs to a 4-cylinder gasoline engine (displacement 2000cc), idling 1 minute → engine speed 3500 rpm, fully open state 30 minutes → engine speed 2000 rpm, half open state 20 minutes One cycle was operated for 1000 hours (center electrode temperature of about 780 ° C.), and the expansion amount of the spark discharge gap g of the plug after the operation was measured. FIG. 4 shows the result in relation to the content of Rh in the alloy and the increase amount of the spark discharge gap.
【００１８】条件Ｂにおいては、チップの合金組成範囲
が本発明の範囲に属するプラグについては、火花放電ギ
ャップｇの増加が小さいのに対し、比較例（Ｒｈ６０重
量％以上、及びＰｔ−Ｉｒ合金）のプラグは火花放電ギ
ャップが著しく拡大していることがわかる。また、それ
よりも高負荷の条件Ａにおいては、実施例と比較例との
間における火花放電ギャップ増加量の差がさらに顕著と
なっている。また、Ｒｈの含有量範囲が３〜５０重量％
から７〜３０重量％へ、さらには１５〜２５重量％へと
変化するに伴い、ギャップ増加量が段階的に減少してお
り、特にＲｈ含有量が１５〜２５重量％であるチップを
使用したプラグにおいては、厳しい運転条件にも拘わら
ず、非常に良好な耐久性を示していることがわかる。Under the condition B, the increase in spark discharge gap g is small for the plugs whose alloy composition range falls within the range of the present invention, whereas the comparative example (Rh 60 wt% or more, and Pt-Ir alloy). It can be seen that the spark discharge gap of the plug is markedly expanded. Further, under the condition A under a higher load than that, the difference in the spark discharge gap increase amount between the example and the comparative example becomes more remarkable. Further, the content range of Rh is 3 to 50% by weight.
To 7 to 30% by weight, and further to 15 to 25% by weight, the amount of increase in the gap gradually decreased, and in particular, chips having an Rh content of 15 to 25% by weight were used. It can be seen that the plug exhibits very good durability despite the severe operating conditions.
【００１９】なお、Ｒｈ含有量が１５〜２５重量％の合
金素材については、Ｒｈを含有しないＩｒ単体金属素材
と比較して、熱間圧延により板材形状に加工する際にク
ラックが発生しにくかった。Regarding the alloy material having a Rh content of 15 to 25% by weight, cracks were less likely to occur when hot-rolled into a plate shape, as compared with an Ir simple metal material containing no Rh. .
【００２０】（実施例２）所定量のＩｒとＲｈを配合・
溶解することにより、Ｒｈを１５、１８、２０、２２及
び２５重量％の各比率で含有し残部が実質的にＩｒで構
成された合金を用意し、これをチップ材料として用いて
実施例１と同様のプラグを作製した。そして、これらプ
ラグに対し実施例１の条件Ａよりもさらに厳しい下記条
件Ｃにて性能試験を行った。条件Ｃ：４気筒ガソリンエ
ンジン（排気量１６００cc）にそれらプラグを取り付
け、スロットル全開状態、エンジン回転数６２５０ｒｐ
ｍにて３００時間連続運転し（中心電極温度約９５０
℃）、運転終了後のプラグの火花放電ギャップｇの拡大
量を測定した。図５は、その結果を、合金中のＲｈの含
有量と火花放電ギャップ増加量との関係で示したもので
ある。(Example 2) A predetermined amount of Ir and Rh were mixed.
By melting, an alloy containing Rh in the proportions of 15, 18, 20, 22 and 25% by weight and the balance substantially composed of Ir was prepared. A similar plug was made. Then, a performance test was performed on these plugs under the following condition C, which is more severe than the condition A of the first embodiment. Condition C: 4-cylinder gasoline engine (displacement 1600cc) with those plugs attached, throttle fully open, engine speed 6250rp
continuous operation for 300 hours (center electrode temperature about 950
C), and the amount of expansion of the spark discharge gap g of the plug after the operation was completed was measured. FIG. 5 shows the result in relation to the content of Rh in the alloy and the increase amount of the spark discharge gap.
【００２１】該結果によれば、Ｒｈの含有量範囲が１８
〜２２重量％であるチップを使用したプラグにおいて
は、Ｒｈ含有量が該範囲外にあるチップを使用したもの
に比べて、条件Ｂよりさらに厳しい条件Ｃにおいてもギ
ャップ増加量が小さく、より良好な耐久性を示している
ことがわかる。According to the results, the Rh content range is 18
In a plug using a chip having a content of ˜22% by weight, the gap increase amount is small even in the condition C, which is more severe than the condition B, and is better than that in the plug using the chip having an Rh content outside the range. It can be seen that it shows durability.
【図１】本発明のスパークプラグを示す正面部分断面
図。FIG. 1 is a front partial cross-sectional view showing a spark plug of the present invention.
【図２】その要部を示す拡大断面図。FIG. 2 is an enlarged cross-sectional view showing the main part thereof.
【図３】発火部を構成する合金中のＲｈ含有量と、火花
放電ギャップの拡大量との関係を示すグラフ（実施例
１：条件Ａ）。FIG. 3 is a graph showing the relationship between the Rh content in the alloy forming the ignition part and the expansion amount of the spark discharge gap (Example 1: Condition A).
【図４】発火部を構成する合金中のＲｈ含有量と、火花
放電ギャップの拡大量との関係を示すグラフ（実施例
１：条件Ｂ）。FIG. 4 is a graph showing the relationship between the Rh content in the alloy forming the ignition part and the expansion amount of the spark discharge gap (Example 1: Condition B).
【図５】発火部を構成する合金中のＲｈ含有量と、火花
放電ギャップの拡大量との関係を示すグラフ（実施例
２：条件Ｃ）。FIG. 5 is a graph showing the relationship between the Rh content in the alloy forming the ignition part and the expansion amount of the spark discharge gap (Example 2: Condition C).
１ 主体金具 ２ 絶縁体 ３ 中心電極 ４ 接地電極 ３１ 発火部（チップ） ３２ 対向する発火部（チップ） ｇ 火花放電ギャップ 1 metal shell 2 insulator 3 Center electrode 4 ground electrode 31 Firing part (chip) 32 Opposing ignition part (chip) g Spark discharge gap
フロントページの続き (56)参考文献 特開 平７−37674（ＪＰ，Ａ) 特開 平４−329286（ＪＰ，Ａ) 特開 平７−268574（ＪＰ，Ａ) 特開 平７−37673（ＪＰ，Ａ) 特開 平７−37677（ＪＰ，Ａ) 特開 平６−112261（ＪＰ，Ａ) 特開 平９−7733（ＪＰ，Ａ) 特開 平10−32076（ＪＰ，Ａ) 特公 昭61−31945（ＪＰ，Ｂ２) 欧州公開702093（ＥＰ，Ａ１) (58)調査した分野(Int.Cl.7，ＤＢ名) H01T 13/00 - 13/56 Continuation of front page (56) Reference JP-A-7-37674 (JP, A) JP-A-4-329286 (JP, A) JP-A-7-268574 (JP, A) JP-A-7-37673 (JP , A) JP-A-7-37677 (JP, A) JP-A-6-112261 (JP, A) JP-A-9-7733 (JP, A) JP-A-10-32076 (JP, A) JP-B 61-31945 (JP, B2) European publication 702093 (EP, A1) (58) Fields investigated (Int.Cl. 7 , DB name) H01T 13 / 00-13 / 56
Claims (5)
られた絶縁体と、前記絶縁体の外側に設けられた主体金
具と、その主体金具に一端が結合されるとともに他端側
が側方に曲げ返されて、その側面が前記中心電極の先端
部と対向するように配置された接地電極と、前記中心電
極に固着されて火花放電ギャップを形成する発火部とを
備え、 前記中心電極の先端面に、Ｉｒを主体としてＲｈを１５
〜２５重量％の範囲で含有する組成の合金からなるチッ
プであって、前記組成の溶解合金を７００℃以上の温度
で熱間圧延又は熱間鍛造により線状あるいはロッド状に
加工した後、これを長さ方向に所定長に切断して製造さ
れたものを重ね合わせ、その接合面外縁部に沿って、前
記チップと前記中心電極とにまたがる溶接部を形成する
ことにより、Ｉｒを主体としてＲｈを１５〜２５重量％
の範囲で含有する組成の合金からなる発火部を形成した
ことを特徴とするスパークプラグ。1. A center electrode, an insulator provided outside the center electrode, a metal shell provided outside the insulator, one end coupled to the metal shell, and the other end sideways. And a ground electrode arranged so that its side surface faces the tip of the center electrode, and an ignition part that is fixed to the center electrode to form a spark discharge gap. the distal end surface, the Rh mainly of Ir 15
A chip made of an alloy having a composition contained in the range of up to 25% by weight , the molten alloy having the composition is processed into a linear or rod shape by hot rolling or hot forging at a temperature of 700 ° C. or higher, Are cut to a predetermined length in the longitudinal direction and are overlapped with each other, and a welded portion extending over the tip and the center electrode is formed along the outer edge of the joint surface, whereby Rh is mainly composed of Ir. 15 to 25% by weight
A spark plug formed by forming an ignition part made of an alloy having a composition contained in the range.
られた絶縁体と、前記絶縁体の外側に設けられた主体金
具と、その主体金具に一端が結合されるとともに他端側
が側方に曲げ返されて、その側面が前記中心電極の先端
部と対向するように配置された接地電極と、前記中心電
極に固着されて火花放電ギャップを形成する発火部とを
備え、 前記中心電極の先端面に、Ｉｒを主体としてＲｈを１５
〜２５重量％の範囲で含有する組成の合金からなるチッ
プであって、前記組成の溶解合金を７００℃以上の温度
で熱間圧延により板状に加工し、さらにその板材を熱間
打抜き加工により所定の形状に打ち抜いて製造されたも
のを重ね合わせ、その接合面外縁部に沿って、前記チッ
プと前記中心電極とにまたがる溶接部を形成することに
より、Ｉｒを主体としてＲｈを１５〜２５重量％の範囲
で含有する組成の合金からなる発火部を形成したことを
特徴とするスパークプラグ。2. A center electrode, an insulator provided outside the center electrode, a metal shell provided outside the insulator, one end coupled to the metal shell, and the other end sideways. And a ground electrode arranged so that its side surface faces the tip of the center electrode, and an ignition part that is fixed to the center electrode to form a spark discharge gap. the distal end surface, the Rh mainly of Ir 15
A chip made of an alloy having a composition contained in the range of up to 25% by weight , the molten alloy having the composition described above is processed into a plate shape by hot rolling at a temperature of 700 ° C. or higher, and the plate material is further hot stamped. 15h to 25wt with Rh mainly composed of Ir by stacking products manufactured by punching into a predetermined shape, and forming a welded portion extending over the tip and the center electrode along the outer edge of the joint surface. A spark plug formed by forming an ignition part made of an alloy having a composition contained in the range of % .
８〜２２重量％の範囲で含有する請求項１又は２に記載
のスパークプラグ。3. The alloy forming the ignition part has Rh of 1 or less.
The spark plug according to claim 1 or 2, wherein the spark plug is contained in a range of 8 to 22% by weight.
られた絶縁体と、前記絶縁体の外側に設けられた主体金
具と、その主体金具に一端が結合され、他端側が前記中
心電極と対向するように配置された接地電極と、前記中
心電極に固着されて火花放電ギャップを形成する発火部
とを備えたスパークプラグを製造するために、 Ｉｒを主体としてＲｈを１５〜２５重量％の範囲で含有
する溶解合金を、７００℃以上の温度で熱間圧延又は熱
間鍛造により線状あるいはロッド状に加工した後、これ
を長さ方向に所定長に切断してチップとなし、該チップ
を前記中心電極に溶接接合して、前記発火部を形成する
ことを特徴とするスパークプラグの製造方法。4. A center electrode, an insulator provided outside the center electrode, a metal shell provided outside the insulator, and one end coupled to the metal shell, the other end side being the center electrode. In order to manufacture a spark plug provided with a ground electrode arranged to face with the spark plug and a sparking part fixed to the center electrode to form a spark discharge gap, 15 to 25% by weight of Rh is mainly composed of Ir. The molten alloy contained in the range of is processed into a linear or rod shape by hot rolling or hot forging at a temperature of 700 ° C. or higher, and then cut into a predetermined length in the length direction to form a chip. A method for manufacturing a spark plug, characterized in that a tip is welded to the center electrode to form the ignition part.
られた絶縁体と、前記絶縁体の外側に設けられた主体金
具と、その主体金具に一端が結合され、他端側が前記中
心電極と対向するように配置された接地電極と、前記中
心電極に固着されて火花放電ギャップを形成する発火部
とを備えたスパークプラグを製造するために、 Ｉｒを主体としてＲｈを１５〜２５重量％の範囲で含有
する溶解合金を、７００℃以上の温度で熱間圧延により
板状に加工し、さらにその板材を熱間打抜き加工により
所定の形状に打ち抜いてチップとなし、該チップを前記
中心電極に溶接接合して、前記発火部を形成することを
特徴とするスパークプラグの製造方法。5. A center electrode, an insulator provided outside the center electrode, a metal shell provided outside the insulator, and one end coupled to the metal shell, the other end side being the center electrode. In order to manufacture a spark plug provided with a ground electrode arranged to face with the spark plug and a sparking part fixed to the center electrode to form a spark discharge gap, 15 to 25% by weight of Rh is mainly composed of Ir. The molten alloy contained in the range of 1) is processed into a plate shape by hot rolling at a temperature of 700 ° C. or higher, and the plate material is punched into a predetermined shape by hot punching to form a chip. A method for manufacturing a spark plug, characterized in that the ignition part is formed by welding and joining to a spark plug.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33511996A JP3461670B2 (en) | 1996-06-28 | 1996-11-28 | Spark plug and its manufacturing method |
| KR1019970027677A KR100355886B1 (en) | 1996-06-28 | 1997-06-26 | Spark Plug and Manufacturing Method |
| DE69703011T DE69703011T3 (en) | 1996-06-28 | 1997-06-27 | spark plug |
| EP99122560A EP0975075A3 (en) | 1996-06-28 | 1997-06-27 | A method for producing a spark plug |
| EP97110583A EP0817341B2 (en) | 1996-06-28 | 1997-06-27 | Spark plug |
| CN97113548A CN1059293C (en) | 1996-06-28 | 1997-06-27 | Spark plug |
| US08/883,145 US5793793A (en) | 1996-06-28 | 1997-06-27 | Spark plug |
| US11/495,524 USRE43758E1 (en) | 1996-06-28 | 2006-07-31 | Spark plug with alloy chip |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8-188347 | 1996-06-28 | ||
| JP18834796 | 1996-06-28 | ||
| JP33511996A JP3461670B2 (en) | 1996-06-28 | 1996-11-28 | Spark plug and its manufacturing method |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34647099A Division JP2000150109A (en) | 1999-01-01 | 1999-12-06 | Spark plug |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1074575A JPH1074575A (en) | 1998-03-17 |
| JP3461670B2 true JP3461670B2 (en) | 2003-10-27 |
Family
ID=26504866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33511996A Expired - Lifetime JP3461670B2 (en) | 1996-06-28 | 1996-11-28 | Spark plug and its manufacturing method |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | USRE43758E1 (en) |
| EP (2) | EP0975075A3 (en) |
| JP (1) | JP3461670B2 (en) |
| KR (1) | KR100355886B1 (en) |
| CN (1) | CN1059293C (en) |
| DE (1) | DE69703011T3 (en) |
Families Citing this family (5)
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|---|---|---|---|---|
| JP2002231412A (en) * | 2001-01-31 | 2002-08-16 | Ngk Spark Plug Co Ltd | Method of manufacturing spark plug and manufacturing device |
| JP4121342B2 (en) * | 2001-11-13 | 2008-07-23 | 日本特殊陶業株式会社 | Metal part for plug with chromate coating and method for manufacturing the same |
| US8390183B2 (en) * | 2008-03-27 | 2013-03-05 | Ngk Spark Plug Co., Ltd. | Spark plug and method for manufacturing spark plug |
| DE102010032412B4 (en) * | 2010-07-27 | 2012-03-08 | Dkt Verwaltungs-Gmbh | Method for producing a starting electrode for a prechamber spark plug and prechamber spark plug |
| JP7057935B2 (en) * | 2016-12-22 | 2022-04-21 | 石福金属興業株式会社 | Heat resistant Ir alloy |
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| JPH0737674A (en) * | 1993-07-26 | 1995-02-07 | Ngk Spark Plug Co Ltd | Spark plug |
| JPH07268574A (en) | 1994-03-25 | 1995-10-17 | Tanaka Kikinzoku Kogyo Kk | Production of iridium wire |
| JP3562533B2 (en) | 1994-08-03 | 2004-09-08 | 株式会社デンソー | Spark plug for internal combustion engine |
| GB9418705D0 (en) † | 1994-09-16 | 1994-11-16 | Johnson Matthey Plc | Improvements in high temperature articles |
| GB2302367B (en) * | 1995-06-15 | 1998-11-25 | Nippon Denso Co | Spark plug for internal combustion engine |
| JP2877035B2 (en) | 1995-06-15 | 1999-03-31 | 株式会社デンソー | Spark plug for internal combustion engine |
| JPH09219274A (en) * | 1995-12-06 | 1997-08-19 | Denso Corp | Spark plug |
| US5973443A (en) | 1996-05-06 | 1999-10-26 | Alliedsignal Inc. | Spark plug electrode tip for internal combustion engine |
| JP3000955B2 (en) | 1996-05-13 | 2000-01-17 | 株式会社デンソー | Spark plug |
| GB2479540A (en) | 2010-04-13 | 2011-10-19 | Adam Ford | Corrupting and erasing data on a storage device when computer casing is broken |
-
1996
- 1996-11-28 JP JP33511996A patent/JP3461670B2/en not_active Expired - Lifetime
-
1997
- 1997-06-26 KR KR1019970027677A patent/KR100355886B1/en not_active IP Right Cessation
- 1997-06-27 EP EP99122560A patent/EP0975075A3/en not_active Withdrawn
- 1997-06-27 EP EP97110583A patent/EP0817341B2/en not_active Expired - Lifetime
- 1997-06-27 DE DE69703011T patent/DE69703011T3/en not_active Expired - Lifetime
- 1997-06-27 CN CN97113548A patent/CN1059293C/en not_active Expired - Lifetime
-
2006
- 2006-07-31 US US11/495,524 patent/USRE43758E1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE69703011D1 (en) | 2000-10-12 |
| USRE43758E1 (en) | 2012-10-23 |
| KR980006677A (en) | 1998-03-30 |
| EP0975075A3 (en) | 2000-02-02 |
| DE69703011T3 (en) | 2004-05-27 |
| KR100355886B1 (en) | 2002-12-26 |
| JPH1074575A (en) | 1998-03-17 |
| EP0817341A1 (en) | 1998-01-07 |
| CN1059293C (en) | 2000-12-06 |
| EP0817341B1 (en) | 2000-09-06 |
| CN1170980A (en) | 1998-01-21 |
| EP0975075A2 (en) | 2000-01-26 |
| DE69703011T2 (en) | 2001-01-11 |
| EP0817341B2 (en) | 2003-12-10 |
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