JPH0660959A - Spark plug for internal combustion engine - Google Patents
Spark plug for internal combustion engineInfo
- Publication number
- JPH0660959A JPH0660959A JP23654892A JP23654892A JPH0660959A JP H0660959 A JPH0660959 A JP H0660959A JP 23654892 A JP23654892 A JP 23654892A JP 23654892 A JP23654892 A JP 23654892A JP H0660959 A JPH0660959 A JP H0660959A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- discharge
- spark plug
- materials
- relaxation
- 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
- 238000002485 combustion reaction Methods 0.000 title claims description 9
- 238000009792 diffusion process Methods 0.000 claims abstract description 50
- 239000000463 material Substances 0.000 claims abstract description 29
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 18
- 239000000956 alloy Substances 0.000 claims abstract description 18
- 239000007772 electrode material Substances 0.000 claims abstract description 10
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims abstract description 3
- 239000002184 metal Substances 0.000 claims abstract description 3
- 239000002131 composite material Substances 0.000 claims description 26
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 14
- 239000012212 insulator Substances 0.000 claims description 10
- 229910052697 platinum Inorganic materials 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- 238000005304 joining Methods 0.000 claims description 5
- 229910002835 Pt–Ir Inorganic materials 0.000 claims description 4
- 229910002845 Pt–Ni Inorganic materials 0.000 claims description 4
- 229910052741 iridium Inorganic materials 0.000 claims description 4
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims 3
- 150000001875 compounds Chemical class 0.000 abstract 2
- 230000007797 corrosion Effects 0.000 description 14
- 238000005260 corrosion Methods 0.000 description 14
- 230000001590 oxidative effect Effects 0.000 description 11
- 230000008646 thermal stress Effects 0.000 description 7
- 238000003466 welding Methods 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000035882 stress Effects 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910000575 Ir alloy Inorganic materials 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 229910000923 precious metal alloy Inorganic materials 0.000 description 1
- 230000002040 relaxant effect Effects 0.000 description 1
Landscapes
- Spark Plugs (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は，発火部に放電層と緩和
層とよりなる複合チップを設けた内燃機関用スパークプ
ラグに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spark plug for an internal combustion engine, which is provided with a composite chip having a discharge layer and a relaxation layer at an ignition part.
【０００２】[0002]
【従来技術】自動車等のエンジンには，ＰｔもしくはＰ
ｔ合金等の貴金属を，放電部に配設したスパークプラグ
が取り付けられている。該スパークプラグは，最も消耗
の激しい放電部に上記貴金属を配設しているため，メン
テナンスフリーで長期間使用が可能である。一方，省燃
費，排ガス規制といった環境保護の立場から，エンジン
は高圧縮比化，リーンバーン化などの動向がある。この
場合には，エンジンの燃焼室内の温度は上昇することと
なる。そのため，スパークプラグの放電部においては，
貴金属と放電部の電極材料との線膨張係数の差に起因す
る熱応力が大きくなる。2. Description of the Related Art Pt or P is used for engines of automobiles and the like.
A spark plug in which a precious metal such as a t-alloy is arranged in the discharge part is attached. Since the spark plug has the above-mentioned noble metal arranged in the discharge portion, which consumes the most electricity, it is maintenance-free and can be used for a long period of time. On the other hand, from the standpoint of environmental protection such as fuel efficiency and exhaust gas regulations, there is a trend toward higher compression ratios and lean burn of engines. In this case, the temperature inside the combustion chamber of the engine will rise. Therefore, in the discharge part of the spark plug,
The thermal stress due to the difference in linear expansion coefficient between the noble metal and the electrode material of the discharge part becomes large.
【０００３】そこで，特公平３─２２０３３号公報，特
開昭６０─２６２３７４号に示されるように，熱応力を
緩和する緩和層と放電層とを備えた複合チップを用いる
ことが提案されている。複合チップは，緩和層側を放電
部と対面させて，放電部に溶接される。緩和層は，放電
層と放電部との間の線膨張係数を有する。Therefore, as disclosed in JP-B-3-22033 and JP-A-60-262374, it has been proposed to use a composite chip having a relaxation layer for relaxing thermal stress and a discharge layer. . The composite chip is welded to the discharge part with the relaxation layer side facing the discharge part. The relaxation layer has a linear expansion coefficient between the discharge layer and the discharge part.
【０００４】[0004]
【解決しようとする課題】しかしながら，近年において
は，スパークプラグに高性能が期待されている。そのた
め，スパークプラグへの熱負荷が益々増加することにな
る。それ故，予め接合してある放電層と緩和層との接合
面で，熱応力による酸化腐食が発生し，甚だしい場合に
は放電層が脱落し，長期間の使用に支障を来すことにな
る。本発明はかかる問題点に鑑み，放電層の剥離，脱落
を防止することができる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。[Problems to be Solved] However, in recent years, spark plugs are expected to have high performance. Therefore, the heat load on the spark plug will increase more and more. Therefore, oxidative corrosion due to thermal stress occurs at the joint surface between the discharge layer and the relaxation layer that have been joined in advance, and in extreme cases, the discharge layer may fall off, which hinders long-term use. . In view of such problems, the present invention aims to provide a spark plug for an internal combustion engine, which can prevent the discharge layer from peeling and falling off.
【０００５】[0005]
【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，該ハウジングより延設され上記中心電極と
対向させた接地電極とよりなり，かつ上記中心電極或い
は接地電極の少なくとも一方の電極材料の放電部に，放
電層と緩和層とを接合面において予め接合することによ
り形成された複合チップを設けてなり，上記放電層は，
耐火花消耗性の良好な貴金属または貴金属合金よりな
り，上記緩和層は，上記放電層と上記電極材料との間の
線膨張係数の金属又は合金よりなり，上記接合面には，
上記放電層及び緩和層の両材質の接合時における相互拡
散により，両材質の濃度が連続的に変化する拡散層が形
成されており，上記拡散層の厚さは，複合チップが上記
放電部に溶接された状態で３μｍ以上であることを特徴
とする内燃機関用スパークプラグにある。According to the present invention, there is provided an insulator, a center electrode held by the insulator, a housing fixed to the outer periphery of the insulator, and a ground electrode extending from the housing and facing the center electrode. And a composite chip formed by previously bonding a discharge layer and a relaxation layer at a bonding surface to the discharge portion of at least one of the electrode materials of the center electrode and the ground electrode, wherein the discharge layer is ，
The noble metal or noble metal alloy having a good spark consumption resistance, the relaxation layer is made of a metal or alloy having a linear expansion coefficient between the discharge layer and the electrode material, and the joint surface has
A diffusion layer in which the concentrations of both materials of the discharge layer and the relaxation layer are continuously changed by mutual diffusion at the time of joining the materials is formed. The spark plug for an internal combustion engine is characterized by having a thickness of 3 μm or more in a welded state.
【０００６】本発明において最も注目すべきことは，放
電層と緩和層との接合面に，両材質の溶接時における相
互拡散により，両材質の濃度が連続的に変化する拡散層
が形成されており，該拡散層の厚さは，複合チップが上
記放電部に溶接された状態で３μｍ以上であることであ
る。What is most noticeable in the present invention is that a diffusion layer in which the concentration of both materials is continuously changed is formed on the joint surface between the discharge layer and the relaxation layer due to mutual diffusion during welding of both materials. That is, the thickness of the diffusion layer is 3 μm or more when the composite chip is welded to the discharge part.
【０００７】拡散層の厚さが３μｍ未満の場合には，両
材質の熱応力の低減が不充分となり，拡散層に酸化腐食
が発生する。甚だしいときには，放電層が緩和層から離
脱するおそれがある。尚，拡散層の厚みは，複合チップ
製造時の加熱条件により設定する。即ち，拡散層の厚み
を増すためには，加熱温度を上げる，或いは加熱時間を
長くするといった手段をとる。When the thickness of the diffusion layer is less than 3 μm, the thermal stress of both materials is insufficiently reduced, and oxidative corrosion occurs in the diffusion layer. In extreme cases, the discharge layer may separate from the relaxation layer. The thickness of the diffusion layer is set according to the heating conditions when manufacturing the composite chip. That is, in order to increase the thickness of the diffusion layer, the heating temperature is raised or the heating time is lengthened.
【０００８】また，複合チップの成分としてＮｉ，Ｆｅ
等の卑金属が含有されている場合には，真空中，Ｎ2 ガ
ス中，Ａｒガス中，又はＮ2 ＋Ｈ2 ガス中等の非酸化性
の雰囲気下で加圧加熱する。以上のように処理された複
合チップを放電部に溶接する際に，加圧力，ジュール熱
により，複合チップが変形し厚みも減少する。そのた
め，この減少分を見込んで加熱条件を設定する必要があ
る。そこで，放電部に溶接する前における拡散層の厚み
は，溶接後の拡散層の厚みの１．４倍にしておくことが
好ましい。Further, Ni and Fe are used as components of the composite chip.
When a base metal such as the above is contained, it is heated under pressure in a non-oxidizing atmosphere such as vacuum, N 2 gas, Ar gas, or N 2 + H 2 gas. When welding the composite tip processed as described above to the discharge part, the composite tip is deformed by the applied pressure and Joule heat, and the thickness is also reduced. Therefore, it is necessary to set the heating conditions in anticipation of this decrease. Therefore, the thickness of the diffusion layer before welding to the discharge part is preferably 1.4 times the thickness of the diffusion layer after welding.
【０００９】放電層は，Ｐｔ（白金）７０〜１００％
（重量比，以下同じ）とＩｒ（イリジウム）０〜３０％
とからなるＰｔ─Ｉｒ合金であり，且つ上記緩和層はＰ
ｔ６０〜９０％とＮｉ１０〜４０％とからなるＰｔ−Ｎ
ｉ合金であることが好ましい。The discharge layer is Pt (platinum) 70-100%
(Weight ratio, same below) and Ir (iridium) 0-30%
Is a Pt-Ir alloy, and the relaxation layer is P
Pt-N consisting of t60-90% and Ni10-40%
It is preferably an i alloy.
【００１０】上記放電層において，Ｐｔ−Ｉｒ合金が上
記組成の範囲外にある場合には，火花放電による消耗量
が多く，スパークプラグの使用期間が短くなるおそれが
ある。また，上記緩和層において，Ｐｔ−Ｎｉ合金の組
成が上記範囲外にある場合には，緩和層の線膨張係数
が，放電層と電極材料との線膨張係数の範囲外になるお
それがある。そのため，緩和層は冷熱負荷時において，
放電層と電極材料との熱応力を緩和することができず，
両者に亀裂，応力腐食の発生をもたらすおそれがある。If the Pt-Ir alloy is out of the above composition range in the discharge layer, the spark plug may be consumed much and the duration of use of the spark plug may be shortened. When the composition of the Pt-Ni alloy is out of the above range in the relaxation layer, the coefficient of linear expansion of the relaxation layer may be out of the range of the coefficient of linear expansion between the discharge layer and the electrode material. Therefore, the relaxation layer is
The thermal stress between the discharge layer and the electrode material cannot be relaxed,
Both of them may cause cracks and stress corrosion.
【００１１】[0011]
【作用及び効果】本発明においては，放電層と緩和層と
の接合面に，両材質の接合時における相互拡散により，
両材質の濃度が連続的に変化する拡散層が形成されてお
り，また，該拡散層の厚さは，複合チップが上記放電部
に溶接された状態で３μｍ以上である。そのため，放電
層と緩和層との両材質が，拡散層において徐々に変化す
る。即ち，放電層の材質は，拡散層の放電層側から緩和
層側まで，連続的に減少する。また，緩和層の材質は，
拡散層の緩和層側から放電層側まで，連続的に減少す
る。[Operation and effect] In the present invention, due to mutual diffusion at the time of joining of both materials, on the joint surface of the discharge layer and the relaxation layer,
A diffusion layer in which the concentrations of both materials continuously change is formed, and the thickness of the diffusion layer is 3 μm or more when the composite chip is welded to the discharge part. Therefore, the materials of both the discharge layer and the relaxation layer gradually change in the diffusion layer. That is, the material of the discharge layer continuously decreases from the discharge layer side of the diffusion layer to the relaxation layer side. The material of the relaxation layer is
It continuously decreases from the relaxation layer side of the diffusion layer to the discharge layer side.
【００１２】それ故，両材質の線膨張係数の差が，拡散
層において，徐々に変化することになる。従って，冷熱
負荷時の際には，拡散層において両材質の熱応力が緩和
され，両者に亀裂，応力腐食が発生することがない。本
発明によれば，放電層の剥離，脱落を防止することがで
きる内燃機関用スパークプラグを提供することができ
る。Therefore, the difference in linear expansion coefficient between the two materials gradually changes in the diffusion layer. Therefore, at the time of cold load, thermal stress of both materials is relaxed in the diffusion layer, and neither crack nor stress corrosion occurs in both materials. According to the present invention, it is possible to provide a spark plug for an internal combustion engine that can prevent the discharge layer from peeling and falling off.
【００１３】[0013]
実施例１ 本発明にかかる実施例について，図１〜図５を用いて説
明する。本例の内燃機関用スパークプラグ２は，図１，
図２に示すごとく，絶縁碍子２０と，絶縁碍子２０に保
持した中心電極４と，絶縁碍子２０の外周に固定したハ
ウジング２５と，ハウジング２５に取り付けられ上記中
心電極４との間に火花放電用のギャップ５を介して対向
させた接地電極３とよりなる。Example 1 An example according to the present invention will be described with reference to FIGS. The spark plug 2 for an internal combustion engine of this example is shown in FIG.
As shown in FIG. 2, for spark discharge between the insulator 20, the center electrode 4 held by the insulator 20, the housing 25 fixed to the outer periphery of the insulator 20, and the center electrode 4 attached to the housing 25. Of the ground electrode 3 facing each other through the gap 5.
【００１４】接地電極３及び中心電極４の先端には，放
電部３０，４０を設けている。放電部３０には，複合チ
ップ１を設けている。該複合チップ１は，図３（ａ）に
示すごとく，放電層１１と緩和層１９とを接合面１１
０，１９０において予め接合することにより形成されて
いる。Discharge parts 30 and 40 are provided at the tips of the ground electrode 3 and the center electrode 4. The discharge section 30 is provided with the composite chip 1. In the composite chip 1, as shown in FIG.
It is formed by previously bonding at 0 and 190.
【００１５】接合面１１０，１９０の間には，拡散層１
５が形成されている。該拡散層１５は，図３（ｂ）に示
すごとく，放電層１１及び緩和層１９の接合時における
両材質の相互拡散により形成されたもので，両材質の濃
度が連続的に変化している。拡散層１５の厚さは，複合
チップ１が放電部３０に溶接された状態で３μｍであ
る。A diffusion layer 1 is formed between the joint surfaces 110 and 190.
5 is formed. As shown in FIG. 3B, the diffusion layer 15 is formed by mutual diffusion of both materials when the discharge layer 11 and the relaxation layer 19 are joined, and the concentrations of both materials continuously change. . The thickness of the diffusion layer 15 is 3 μm when the composite chip 1 is welded to the discharge part 30.
【００１６】放電層１１は，耐火花消耗性の良好な貴金
属合金として，Ｐｔ８０％とＩｒ２０％よりなるＰｔ−
Ｉｒ合金を用いている。放電層１１の線膨張係数は，９
×１０-6／℃である。接地電極３の放電部３０は，Ｎｉ
基耐熱合金を用いており，その線膨張係数は，１５×１
０-6／℃である。緩和層１９は，Ｐｔ８０％とＮｉ２０
％とよりなるＰｔ−Ｎｉ合金を用いている。緩和層１９
の線膨張係数は，１２×１０-6／℃である。尚，線膨張
係数は，５０℃〜８００℃の間での測定値である。The discharge layer 11 is made of Pt-containing 80% Pt and 20% Ir as a precious metal alloy having a good spark wear resistance.
Ir alloy is used. The linear expansion coefficient of the discharge layer 11 is 9
× 10 −6 / ° C. The discharge part 30 of the ground electrode 3 is made of Ni
A base heat-resistant alloy is used, and its linear expansion coefficient is 15 x 1
It is 0 -6 / ° C. The relaxation layer 19 is made of Pt 80% and Ni 20
% Of Pt—Ni alloy is used. Relaxation layer 19
Has a linear expansion coefficient of 12 × 10 −6 / ° C. The linear expansion coefficient is a measured value between 50 ° C and 800 ° C.
【００１７】上記接地電極３は，ハウジング２５より延
設されている。また，中心電極４及び接地電極３は，Ｎ
ｉ基耐熱合金を用いた電極材料により形成されている。
また中心電極４の伝熱性を向上させるため，Ｃｕ材４２
が中心電極４内に封入されている。The ground electrode 3 extends from the housing 25. Further, the center electrode 4 and the ground electrode 3 are N
It is formed of an electrode material using an i-based heat resistant alloy.
Further, in order to improve the heat transfer property of the center electrode 4, the Cu material 42
Are enclosed in the center electrode 4.
【００１８】放電層１１と緩和層１９とを接合する際に
は，両材質を重ね合わせ，加圧しつつ，１０-5ｔｏｒｒ
以下の真空，もしくはＡｒガス等の非酸化雰囲気下で，
１０００℃×１時間程度の熱処理を行う。これにより，
放電層１１と緩和層１９との接合面１１０，１９０の間
に，拡散層１５が形成される。When the discharge layer 11 and the relaxation layer 19 are joined together, both materials are superposed on each other and pressurized while being 10 -5 torr.
In the following vacuum or non-oxidizing atmosphere such as Ar gas,
Heat treatment is performed at 1000 ° C. for about 1 hour. By this,
The diffusion layer 15 is formed between the junction surfaces 110 and 190 of the discharge layer 11 and the relaxation layer 19.
【００１９】複合チップ１，放電層１１，拡散層１５，
緩和層１９の厚さは，複合チップ１を放電部３０に溶接
する前では，０．５ｍｍ，０．３５ｍｍ，４．２μｍ，
０．１５ｍｍである。溶接した後では，複合チップ１，
放電層１１，拡散層１５，緩和層１９の厚さは，溶接す
る前の７０％に減少した。Composite chip 1, discharge layer 11, diffusion layer 15,
The thickness of the relaxation layer 19 is 0.5 mm, 0.35 mm, 4.2 μm, before welding the composite chip 1 to the discharge part 30.
It is 0.15 mm. After welding, the composite tip 1,
The thickness of the discharge layer 11, the diffusion layer 15, and the relaxation layer 19 was reduced to 70% before welding.
【００２０】次に，本例の作用効果について説明する。
本例においては，放電層１１と緩和層１９との接合面１
１０，１９０に，両材質の接合時における相互拡散によ
り，両材質の濃度が連続的に変化する拡散層１５が形成
されている。該拡散層１５の厚さは，複合チップ１が放
電部３０に溶接された状態で３μｍである。Next, the function and effect of this example will be described.
In this example, the joint surface 1 between the discharge layer 11 and the relaxation layer 19 is
Diffusion layers 15 in which the concentrations of both materials continuously change are formed on 10, 190 by mutual diffusion during joining of both materials. The thickness of the diffusion layer 15 is 3 μm when the composite chip 1 is welded to the discharge part 30.
【００２１】そのため，放電層１１と緩和層１９との両
材質が，拡散層１５において徐々に変化する。即ち，放
電層１１の材質は，拡散層１５の放電層１１側から緩和
層１９側まで，連続的に減少する。また，緩和層１９の
材質は，拡散層１５の緩和層１９側から放電層１１側ま
で，連続的に減少する。Therefore, the materials of both the discharge layer 11 and the relaxation layer 19 gradually change in the diffusion layer 15. That is, the material of the discharge layer 11 continuously decreases from the discharge layer 11 side of the diffusion layer 15 to the relaxation layer 19 side. Further, the material of the relaxation layer 19 continuously decreases from the relaxation layer 19 side of the diffusion layer 15 to the discharge layer 11 side.
【００２２】それ故，両材質の線膨張係数の差が，拡散
層１５において，徐々に変化することになる。よって，
冷熱負荷時の際には，拡散層１５において両材質の熱応
力が緩和され，両者に亀裂，応力腐食が発生することが
ない。従って，スパークプラグ２の寿命が増え，長期間
に渡ってスパークプラグ２を使用することができる。Therefore, the difference in the linear expansion coefficient between the two materials gradually changes in the diffusion layer 15. Therefore,
At the time of cold load, the thermal stress of both materials is relaxed in the diffusion layer 15, and neither crack nor stress corrosion occurs in both materials. Therefore, the life of the spark plug 2 is increased, and the spark plug 2 can be used for a long time.
【００２３】次に，本例のスパークプラグにつき，拡散
層の厚みを種々に変えて，火花放電による拡散層の耐酸
化腐食性に関する評価試験を行った。拡散層の厚みは，
放電層と緩和層とを接合する際の加熱条件を変えること
により変化させた。Next, with respect to the spark plug of this example, an evaluation test was performed on the oxidation corrosion resistance of the diffusion layer due to spark discharge while changing the thickness of the diffusion layer variously. The thickness of the diffusion layer is
It was changed by changing the heating conditions when joining the discharge layer and the relaxation layer.
【００２４】上記試験は，上記スパークプラグを２００
０ｃｃ，水冷，４サイクル，６気筒の自動車用エンジン
に装着した状態で，スロットル全開，６０００ｒｐｍ×
１分間，アイドリング×１分間を１００時間の間繰り返
すことにより，上記スパークプラグに冷熱負荷をかけ
た。その結果を図５に示す。The above test was carried out using the above spark plug 200 times.
0cc, water-cooled, 4-cycle, 6-cylinder 6-cylinder automobile engine mounted, throttle fully open, 6000rpm ×
A cold load was applied to the spark plug by repeating idling × 1 minute for 1 hour for 100 hours. The result is shown in FIG.
【００２５】同図において，横軸は複合チップが放電部
に溶接された状態での拡散層の厚みである。また，縦軸
は，放電層と緩和層との間の酸化腐食率を示す。該酸化
腐食率は，図４に示すごとく，酸化腐食部５０，５１，
及び複合チップ１の径方向の長さを，それぞれａ，ｂ，
ｄとし，（ａ＋ｂ）×１００／ｄの式により算出した。In the figure, the horizontal axis represents the thickness of the diffusion layer when the composite chip is welded to the discharge part. The vertical axis shows the oxidative corrosion rate between the discharge layer and the relaxation layer. The oxidative corrosion rate is as shown in FIG.
And the radial length of the composite chip 1 are a, b,
d, and calculated by the formula of (a + b) × 100 / d.
【００２６】図５より知られるごとく，拡散層の厚さが
３μｍ以上の場合には，酸化腐食が発生しなかった。一
方，拡散層の厚さが３μｍ未満の場合には，酸化腐食が
発生した。このことからも，本例にかかる拡散層は，耐
酸化腐食性に優れた効果を発揮することが分かる。As is known from FIG. 5, when the thickness of the diffusion layer was 3 μm or more, oxidative corrosion did not occur. On the other hand, when the thickness of the diffusion layer was less than 3 μm, oxidative corrosion occurred. From this, it can be seen that the diffusion layer according to this example exhibits an excellent effect on oxidative corrosion resistance.
【００２７】実施例２ 本例のスパークプラグは，Ｐｔ６０％・Ｎｉ４０％又は
Ｐｔ９０％・Ｎｉ１０％よりなるＰｔ−Ｎｉ合金からな
る緩和層と，Ｐｔ１００％又はＰｔ７０％・Ｉｒ３０％
よりなるＰｔ−Ｉｒ合金とからなる放電層を設けてい
る。その他は，実施例１と同様である。本例のスパーク
プラグについても，緩和層と放電層の上記組成の組み合
わせを種々に変えて，実施例１と同様に，火花放電によ
る拡散層の耐酸化腐食性に関する評価試験を行った。そ
の結果，実施例１と同様の結果を得た。Example 2 The spark plug of this example has a relaxation layer made of a Pt-Ni alloy consisting of 60% Pt / 40% Ni or 90% Pt / 10% Ni, and 100% Pt or 70% Pt / 30% Ir.
And a discharge layer made of a Pt-Ir alloy. Others are the same as in the first embodiment. Also for the spark plug of this example, various combinations of the compositions of the relaxation layer and the discharge layer were changed, and an evaluation test on the oxidation corrosion resistance of the diffusion layer due to spark discharge was performed in the same manner as in Example 1. As a result, the same results as in Example 1 were obtained.
【００２８】実施例３ 本例のスパークプラグは，図６に示すごとく，中心電極
４の放電部４０に複合チップ１を設けている。接地電極
３の放電部３０には放電層１１を設けている。その他
は，実施例１と同様である。本例においても，実施例１
と同様の効果を得ることができる。Embodiment 3 In the spark plug of this embodiment, as shown in FIG. 6, the composite tip 1 is provided on the discharge part 40 of the center electrode 4. A discharge layer 11 is provided on the discharge part 30 of the ground electrode 3. Others are the same as in the first embodiment. Also in this example, Example 1
The same effect as can be obtained.
【００２９】実施例４ 本例のスパークプラグは，図７に示すごとく，接地電極
３，中心電極４の放電部３０，４０の双方に，複合チッ
プ１を取り付けている。その他は，実施例１と同様であ
る。本例においても，実施例１と同様の効果を得ること
ができる。Example 4 In the spark plug of this example, as shown in FIG. 7, the composite tip 1 is attached to both the ground electrode 3 and the discharge parts 30 and 40 of the center electrode 4. Others are the same as in the first embodiment. Also in this example, the same effect as that of the first embodiment can be obtained.
【図１】実施例１のスパークプラグの要部拡大断面図。FIG. 1 is an enlarged sectional view of essential parts of a spark plug according to a first embodiment.
【図２】実施例１のスパークプラグの一部断面側面図。FIG. 2 is a partial cross-sectional side view of the spark plug according to the first embodiment.
【図３】実施例１にかかる，複合チップの要部拡大断面
図，及び複合チップにおけるＮｉ−Ｉｒ組成分布を示す
線図。FIG. 3 is an enlarged cross-sectional view of a main part of a composite chip according to Example 1, and a diagram showing a Ni—Ir composition distribution in the composite chip.
【図４】実施例１にかかる，酸化腐食率の算出方法を説
明するための説明図。FIG. 4 is an explanatory diagram for explaining a method of calculating an oxidative corrosion rate according to the first embodiment.
【図５】実施例１にかかる，拡散層の厚みと酸化腐食率
の関係を示す線図。FIG. 5 is a diagram showing the relationship between the thickness of the diffusion layer and the oxidative corrosion rate according to the first embodiment.
【図６】実施例３のスパークプラグの要部拡大断面図。FIG. 6 is an enlarged sectional view of a main part of a spark plug according to a third embodiment.
【図７】実施例４のスパークプラグの一部断面側面図。FIG. 7 is a partial cross-sectional side view of the spark plug according to the fourth embodiment.
１．．．複合チップ， １１．．．放電層， １５．．．拡散層， １９．．．緩和層， ２．．．スパークプラグ， ２０．．．絶縁碍子， ２５．．．ハウジング， ３．．．接地電極， ３０，４０．．．放電部， ４．．．中心電極， 1. ． ． Composite chip, 11. ． ． Discharge layer, 15. ． ． Diffusion layer, 19. ． ． Relaxation layer, 2. ． ． Spark plug, 20. ． ． Insulator, 25. ． ． Housing, 3. ． ． Ground electrode, 30, 40. ． ． Discharge unit, 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
ハウジングより延設され上記中心電極と対向させた接地
電極とよりなり，かつ上記中心電極或いは接地電極の少
なくとも一方の電極材料の放電部に，放電層と緩和層と
を接合面において予め接合することにより形成された複
合チップを設けてなり，上記放電層は，耐火花消耗性の
良好な貴金属または貴金属合金よりなり，上記緩和層
は，上記放電層と上記電極材料との間の線膨張係数の金
属又は合金よりなり，上記接合面には，上記放電層及び
緩和層の両材質の接合時における相互拡散により，両材
質の濃度が連続的に変化する拡散層が形成されており，
上記拡散層の厚さは，複合チップが上記放電部に溶接さ
れた状態で３μｍ以上であ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 extending from the housing and facing the center electrode, and A composite chip formed by previously bonding a discharge layer and a relaxation layer at a bonding surface is provided at a discharge portion of at least one of electrode materials of a center electrode and a ground electrode, and the discharge layer has a spark wear resistance. Of a noble metal or a noble metal alloy having good linearity, the relaxation layer is made of a metal or alloy having a linear expansion coefficient between the discharge layer and the electrode material, and both the discharge layer and the relaxation layer are provided on the joint surface. Due to mutual diffusion during joining of materials, a diffusion layer in which the concentration of both materials changes continuously is formed.
The spark plug for an internal combustion engine, wherein the thickness of the diffusion layer is 3 μm or more when the composite tip is welded to the discharge part.
（白金）７０〜１００％（重量比，以下同じ）とＩｒ
（イリジウム）０〜３０％とからなるＰｔ─Ｉｒ合金で
あり，且つ上記緩和層はＰｔ６０〜９０％とＮｉ（ニッ
ケル）１０〜４０％とからなるＰｔ−Ｎｉ合金であるこ
とを特徴とする内燃機関用スパークプラグ。2. The discharge layer according to claim 1, wherein the discharge layer is Pt.
(Platinum) 70 to 100% (weight ratio, same below) and Ir
Internal combustion characterized by being a Pt-Ir alloy composed of (iridium) 0 to 30%, and the relaxation layer being a Pt-Ni alloy composed of Pt 60 to 90% and Ni (nickel) 10 to 40%. Spark plug for engine.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23654892A JP3724815B2 (en) | 1992-08-12 | 1992-08-12 | Spark plug for internal combustion engine |
| US08/104,203 US5465022A (en) | 1992-08-12 | 1993-08-11 | Spark plug for internal-combustion engine and manufacture method of the same |
| GB9316688A GB2269632B (en) | 1992-08-12 | 1993-08-11 | Method of manufacturing a discharge electrode assembly or a spark plug |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23654892A JP3724815B2 (en) | 1992-08-12 | 1992-08-12 | Spark plug for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0660959A true JPH0660959A (en) | 1994-03-04 |
| JP3724815B2 JP3724815B2 (en) | 2005-12-07 |
Family
ID=17002292
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23654892A Expired - Lifetime JP3724815B2 (en) | 1992-08-12 | 1992-08-12 | Spark plug for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3724815B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7521850B2 (en) | 2005-11-18 | 2009-04-21 | Federal Mogul World Wide, Inc. | Spark plug with multi-layer firing tip |
| KR100947314B1 (en) * | 2009-06-19 | 2010-03-16 | 복대용 | Fluorescent light lamp swap instrument |
| KR20170027291A (en) * | 2015-09-01 | 2017-03-09 | 니뽄 도쿠슈 도교 가부시키가이샤 | Spark plug and method for producing the same |
| DE102018200211A1 (en) | 2017-01-23 | 2018-07-26 | Ngk Spark Plug Co., Ltd. | spark plug |
| KR20180096777A (en) | 2016-01-26 | 2018-08-29 | 니뽄 도쿠슈 도교 가부시키가이샤 | spark plug |
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-
1992
- 1992-08-12 JP JP23654892A patent/JP3724815B2/en not_active Expired - Lifetime
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7581304B2 (en) | 2005-11-18 | 2009-09-01 | Federal-Mogul World Wide, Inc. | Method of forming a spark plug with multi-layer firing tip |
| US7671521B2 (en) | 2005-11-18 | 2010-03-02 | Federal Mogul World Wide, Inc. | Spark plug with multi-layer firing tip |
| US7948159B2 (en) | 2005-11-18 | 2011-05-24 | Federal Mogul World Wide, Inc. | Spark plug with multi-layer firing tip |
| US7521850B2 (en) | 2005-11-18 | 2009-04-21 | Federal Mogul World Wide, Inc. | Spark plug with multi-layer firing tip |
| KR100947314B1 (en) * | 2009-06-19 | 2010-03-16 | 복대용 | Fluorescent light lamp swap instrument |
| KR20170027291A (en) * | 2015-09-01 | 2017-03-09 | 니뽄 도쿠슈 도교 가부시키가이샤 | Spark plug and method for producing the same |
| JP2017050129A (en) * | 2015-09-01 | 2017-03-09 | 日本特殊陶業株式会社 | Spark plug and manufacturing method thereof |
| US10181702B2 (en) | 2015-09-04 | 2019-01-15 | Ngk Spark Plug Co., Ltd. | Spark plug |
| US10312669B2 (en) | 2016-01-26 | 2019-06-04 | Ngk Spark Plug Co., Ltd. | Spark plug |
| KR20180096777A (en) | 2016-01-26 | 2018-08-29 | 니뽄 도쿠슈 도교 가부시키가이샤 | spark plug |
| CN108604779A (en) * | 2016-01-26 | 2018-09-28 | 日本特殊陶业株式会社 | Spark plug |
| CN108604779B (en) * | 2016-01-26 | 2020-12-04 | 日本特殊陶业株式会社 | spark plug |
| DE112016006310B4 (en) | 2016-01-26 | 2023-12-28 | Ngk Spark Plug Co., Ltd. | spark plug |
| CN108346975A (en) * | 2017-01-23 | 2018-07-31 | 日本特殊陶业株式会社 | Spark plug |
| DE102018200211A1 (en) | 2017-01-23 | 2018-07-26 | Ngk Spark Plug Co., Ltd. | spark plug |
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|---|---|
| JP3724815B2 (en) | 2005-12-07 |
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