JP2020187907A - Spark plug - Google Patents
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- JP2020187907A JP2020187907A JP2019091279A JP2019091279A JP2020187907A JP 2020187907 A JP2020187907 A JP 2020187907A JP 2019091279 A JP2019091279 A JP 2019091279A JP 2019091279 A JP2019091279 A JP 2019091279A JP 2020187907 A JP2020187907 A JP 2020187907A
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- spark plug
- core
- core portion
- ground electrode
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- 239000000463 material Substances 0.000 claims abstract description 36
- 229910052751 metal Inorganic materials 0.000 claims description 18
- 239000002184 metal Substances 0.000 claims description 18
- 230000003647 oxidation Effects 0.000 claims description 5
- 238000007254 oxidation reaction Methods 0.000 claims description 5
- 239000011162 core material Substances 0.000 description 89
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 17
- 239000012212 insulator Substances 0.000 description 15
- 239000010949 copper Substances 0.000 description 12
- 229910045601 alloy Inorganic materials 0.000 description 8
- 239000000956 alloy Substances 0.000 description 8
- 239000007769 metal material Substances 0.000 description 8
- 238000003825 pressing Methods 0.000 description 7
- 238000002485 combustion reaction Methods 0.000 description 6
- 238000001125 extrusion Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 229910000510 noble metal Inorganic materials 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 4
- 238000013021 overheating Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000001603 reducing effect Effects 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910000881 Cu alloy Inorganic materials 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000010953 base metal Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000002788 crimping Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000010970 precious metal Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000010273 cold forging Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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- Spark Plugs (AREA)
Abstract
Description
本発明は、スパークプラグに関する。 The present invention relates to a spark plug.
自動車用エンジン等の内燃機関の着火手段として、スパークプラグが用いられている。スパークプラグには、火花放電を発生させるための構成として、中心電極と接地電極とが設けられている。中心電極と接地電極とには、スパークプラグの着火性を向上させるために、電極チップがそれぞれ設けられている。電極チップは、例えば、貴金属材料からなる柱状チップであり、中心電極チップと接地電極チップとの間に所定の火花放電ギャップを形成し、火花放電を発生させて混合気に点火する。 Spark plugs are used as ignition means for internal combustion engines such as automobile engines. The spark plug is provided with a center electrode and a ground electrode as a configuration for generating a spark discharge. An electrode tip is provided on each of the center electrode and the ground electrode in order to improve the ignitability of the spark plug. The electrode tip is, for example, a columnar tip made of a noble metal material, forms a predetermined spark discharge gap between the center electrode tip and the ground electrode tip, generates a spark discharge, and ignites the air-fuel mixture.
また、スパークプラグの中には、接地電極チップを接地電極に取り付ける工程を省くことや、貴金属の使用量を低減させることなどを目的として、接地電極の形状を変更しているものがある。例えば、特許文献１には、接地電極の先端対向部の母材の一部を対向する中心電極へ向けて突出する凸部とし、凸部の表面を覆うように貴金属被覆層が形成されているスパークプラグが開示されている。 Further, some spark plugs have changed the shape of the ground electrode for the purpose of omitting the step of attaching the ground electrode tip to the ground electrode and reducing the amount of precious metal used. For example, in Patent Document 1, a part of the base material of the tip facing portion of the ground electrode is formed as a convex portion protruding toward the facing center electrode, and a precious metal coating layer is formed so as to cover the surface of the convex portion. Spark plugs are disclosed.
ところで、特許文献１には、接地電極の内部に、熱伝導性に優れた金属、例えば、Ｃｕ（すなわち、銅）又はＣｕ合金等の金属材料からなる芯材を有してもよいことが記載されている。このような構成を備えるスパークプラグによれば、熱負荷の厳しい環境で使用されても、熱伝導性に優れる芯材の温度低減効果によって接地電極の温度が耐熱温度を超えてしまうことを抑制できる。しかしながら、このような構成では、Ｃｕ等からなる芯材が、Ｃｕを覆う接地電極の母材と比べてビッカース硬度が小さいために、接地電極に凸部を形成する際に凸部以外の部位において芯材が変形し、この変形に併せて凸部以外の部位の母材も変形してしまう虞があった。その結果、接地電極の凸部以外の部位が所望の形状にならずに変形してしまうという問題点があった。 By the way, Patent Document 1 describes that a core material made of a metal having excellent thermal conductivity, for example, Cu (that is, copper) or a metal material such as a Cu alloy may be provided inside the ground electrode. Has been done. According to the spark plug having such a configuration, it is possible to prevent the temperature of the ground electrode from exceeding the heat resistant temperature due to the temperature reduction effect of the core material having excellent thermal conductivity even when used in an environment with a severe heat load. .. However, in such a configuration, since the core material made of Cu or the like has a lower Vickers hardness than the base material of the ground electrode covering Cu, when a convex portion is formed on the ground electrode, the portion other than the convex portion is formed. There was a risk that the core material would be deformed, and the base material of the portion other than the convex portion would also be deformed along with this deformation. As a result, there is a problem that a portion other than the convex portion of the ground electrode is deformed without forming a desired shape.
そこで、本発明では、かかる背景を鑑みてなされたものであり、凸部を設けた接地電極の内部に芯材を備えた構成において、温度低減効果の確保と、接地電極に凸部を形成する際に凸部以外の部位が変形することを抑制することとを両立させることを目的とする。 Therefore, the present invention has been made in view of such a background, and in a configuration in which a core material is provided inside a ground electrode provided with a convex portion, a temperature reduction effect is ensured and a convex portion is formed on the ground electrode. The purpose is to achieve both the suppression of deformation of parts other than the convex portion at the time.
本発明のスパークプラグは、中心電極と、前記中心電極の外周に配置され、前記中心電極を絶縁保持する主体金具と、前記主体金具に接合される基端部と、前記中心電極と対向する先端部とを有する接地電極と、備え、前記接地電極の前記先端部は、前記中心電極に向かって突出してなる凸部と、前記凸部とは反対側の部分に、前記中心電極に向かって窪んだ凹部とを有するスパークプラグである。このスパークプラグの前記接地電極は、前記接地電極の延設方向と略同一方向に延びる芯部と、前記芯部を覆う母材と、によって構成され、前記芯部は、前記母材よりも熱伝導性に優れる第１の芯部と、前記第１の芯部よりもビッカース硬度が大きく、少なくとも一部が前記第１の芯部に覆われた第２の芯部と、からなる。 The spark plug of the present invention has a center electrode, a main metal fitting arranged on the outer periphery of the center electrode and insulatingly holding the center electrode, a base end portion joined to the main metal fitting, and a tip facing the center electrode. A ground electrode having a portion, and the tip portion of the ground electrode is recessed toward the center electrode in a convex portion formed so as to project toward the center electrode and a portion opposite to the convex portion. It is a spark plug having an electrode recess. The ground electrode of the spark plug is composed of a core portion extending in substantially the same direction as the extension direction of the ground electrode and a base material covering the core portion, and the core portion is hotter than the base material. It is composed of a first core portion having excellent conductivity and a second core portion having a Vickers hardness larger than that of the first core portion and at least partially covered with the first core portion.
上記の構成によれば、母材の中に第１の芯部が存在するので、第１の芯部の熱伝導性によって、接地電極の温度低減効果を確保できる。さらに、第１の芯部よりもビッカース硬度が大きい第２の芯部が第１の芯部の内部に配置されているので、凸部を形成する際に、接地電極のうち凸部以外の部位の変形を抑制できる。 According to the above configuration, since the first core portion exists in the base material, the effect of reducing the temperature of the ground electrode can be ensured by the thermal conductivity of the first core portion. Further, since the second core portion having a Vickers hardness larger than that of the first core portion is arranged inside the first core portion, a portion of the ground electrode other than the convex portion is formed when the convex portion is formed. Deformation can be suppressed.
また、本発明のスパークプラグは、前記第１の芯部の先端が、前記凹部より基端側に位置することをさらに含んでもよい。上記構成によれば、凹部を形成する際に、第１の芯部が凹部の表面に露出することを抑制できるため、金属材料の中で相対的に融点が低いＣｕ又はＣｕ合金等の良熱伝導材が凹部の表面に露出し、融解することを抑制できる。 Further, the spark plug of the present invention may further include that the tip of the first core portion is located on the proximal end side of the recess. According to the above configuration, when the recess is formed, it is possible to prevent the first core portion from being exposed to the surface of the recess, so that good heat of Cu or a Cu alloy having a relatively low melting point among metal materials can be suppressed. It is possible to prevent the conductive material from being exposed on the surface of the recess and melting.
また、本発明のスパークプラグは、前記第１の芯部の先端が、前記凹部の基端側の端より先端側に位置することをさらに含んでもよい。接地電極のうち凹部の基端側の端部付近は、凹部が形成されているために他の部位より肉厚が薄くなっている（以下、この端部付近を基端側薄肉部という）。このため、他の部位と比べて接地電極の基端部側への熱伝導の経路が狭く、蓄熱されやすい。上記構成によれば、母材より熱伝導性に優れる第１の芯部が基端側薄肉部まで延びているので、基端側薄肉部が過熱されることを抑制できる。 Further, the spark plug of the present invention may further include that the tip of the first core portion is located on the tip side of the end on the base end side of the recess. Of the grounding electrodes, the vicinity of the end on the base end side of the recess is thinner than other parts due to the formation of the recess (hereinafter, the vicinity of this end is referred to as the base end side thin wall portion). Therefore, the path of heat conduction to the base end side of the ground electrode is narrower than that of other parts, and heat is easily stored. According to the above configuration, since the first core portion having superior thermal conductivity to the base material extends to the base end side thin wall portion, it is possible to prevent the base end side thin wall portion from being overheated.
また、本発明のスパークプラグは、前記第１の芯部の先端が、前記凹部の先端側の端より先端側に位置することをさらに含んでもよい。接地電極のうち凹部の先端側の端部付近も、凹部が形成されているために他の部位より肉厚が薄くなっている（以下、この端部付近を先端側薄肉部という）。このため、他の部位と比べて接地電極の基端部側への熱伝導の経路が狭く、蓄熱されやすい。さらに、先端側薄肉部よりも先端側部位には、接地電極の先端面を有するために表面積が大きくなっており、周囲から熱を吸収しやすい。上記構成によれば、母材より熱伝導性に優れる第１の芯部が先端側薄肉部よりも先端側部位まで延びているので、先端側薄肉部が過熱されることおよび先端側薄肉部よりも先端側部位が過熱されることを抑制できる。 Further, the spark plug of the present invention may further include that the tip of the first core portion is located closer to the tip side than the tip end side of the recess. Of the grounding electrodes, the vicinity of the tip end side of the recess is also thinner than the other portions due to the formation of the recess (hereinafter, the vicinity of this end is referred to as the tip side thin wall portion). Therefore, the path of heat conduction to the base end side of the ground electrode is narrower than that of other parts, and heat is easily stored. Further, since the tip side portion has the tip surface of the ground electrode rather than the tip side thin wall portion, the surface area is large, and it is easy to absorb heat from the surroundings. According to the above configuration, since the first core portion, which has better thermal conductivity than the base material, extends to the tip side portion rather than the tip side thin wall portion, the tip side thin wall portion is overheated and the tip side thin wall portion However, it is possible to prevent the tip side portion from being overheated.
また、本発明のスパークプラグは、前記第１の芯部が前記凸部内に位置することをさらに含んでもよい。凸部は、先端側薄肉部と、基端側薄肉部の間に配置されているため、凸部が受けた熱が接地電極の他の部位に伝熱しにくい構造となっており、蓄熱されやすい。上記構成によれば、母材より熱伝導性に優れる第１の芯部が凸部まで延びているので、凸部が過熱されることをさらに抑制できる。 Further, the spark plug of the present invention may further include that the first core portion is located in the convex portion. Since the convex portion is arranged between the thin-walled portion on the tip end side and the thin-walled portion on the base end side, the heat received by the convex portion is difficult to transfer to other parts of the ground electrode, and heat is easily stored. .. According to the above configuration, since the first core portion having superior thermal conductivity to the base material extends to the convex portion, overheating of the convex portion can be further suppressed.
また、本発明のスパークプラグは、前記母材が、前記第２の芯部よりも耐酸化性に優れ、前記第２の芯部が、前記凹部より基端側に位置することをさらに含んでもよい。上記構成によれば、凹部を形成することで、耐酸化性に優れる母材の表面に第２の芯部が露出し、凹部の表面が酸化することを抑制できる。 Further, the spark plug of the present invention further includes that the base material is superior in oxidation resistance to the second core portion and the second core portion is located on the base end side of the recess. Good. According to the above configuration, by forming the concave portion, the second core portion is exposed on the surface of the base material having excellent oxidation resistance, and the surface of the concave portion can be suppressed from being oxidized.
また、本発明のスパークプラグは、前記第２の芯部が、前記母材より熱伝導性に優れ、前記第２の芯部の先端が、前記凹部の前記基端部側の端より前記先端部側に位置することをさらに含んでもよい。上述のように、基端側薄肉部は他の部位と比べて接地電極の基端部側への熱伝導の経路が狭く、蓄熱されやすい。上記構成によれば、母材より熱伝導性に優れる第２の芯部が基端側薄肉部まで延びているので、基端側薄肉部が過熱されることを抑制できる。 Further, in the spark plug of the present invention, the second core portion is superior in thermal conductivity to the base material, and the tip of the second core portion is the tip of the recess from the end of the recess on the base end side. It may further include being located on the part side. As described above, the thin-walled portion on the proximal end side has a narrower path for heat conduction to the proximal end portion side of the ground electrode than other portions, and heat is easily stored. According to the above configuration, since the second core portion having superior thermal conductivity to the base material extends to the proximal end side thin wall portion, it is possible to prevent the proximal end side thin wall portion from being overheated.
また、本発明のスパークプラグは、前記第２の芯部の先端が、前記凹部の前記先端部側の端より前記先端部側に位置することをさらに含んでもよい。上述のように、先端側薄肉部は他の部位と比べて接地電極の基端部側への熱伝導の経路が狭く、蓄熱されやすい。さらに、先端側薄肉部よりも先端側部位には、接地電極の先端面を有するために表面積が大きくなっており、周囲から熱を吸収しやすい。上記構成によれば、母材より熱伝導性に優れる第２の芯部が先端側薄肉部よりも先端側部位まで延びているので、先端側薄肉部が過熱されることおよび先端側薄肉部よりも先端側部位が過熱されることを抑制できる。 Further, the spark plug of the present invention may further include that the tip of the second core is located closer to the tip than the end of the recess on the tip side. As described above, the thin-walled portion on the tip side has a narrower path for heat conduction to the base end portion side of the ground electrode as compared with other parts, and heat is easily stored. Further, since the tip side portion has the tip surface of the ground electrode rather than the tip side thin wall portion, the surface area is large, and heat is easily absorbed from the surroundings. According to the above configuration, since the second core portion, which has better thermal conductivity than the base material, extends to the tip side portion rather than the tip side thin wall portion, the tip side thin wall portion is overheated and the tip side thin wall portion However, it is possible to prevent the tip side portion from being overheated.
また、本発明のスパークプラグは、前記第２の芯部が前記凸部内に位置することを含んでもよい。凸部は、先端側薄肉部と、基端側薄肉部の間に配置されているため、凸部が受けた熱が接地電極の他の部位に伝熱しにくい構造となっており、蓄熱されやすい。上記構成によれば、母材より熱伝導性に優れる第２の芯部が凸部まで延びているので、凸部が過熱されることをさらに抑制できる。 Further, the spark plug of the present invention may include that the second core portion is located in the convex portion. Since the convex portion is arranged between the thin-walled portion on the tip end side and the thin-walled portion on the base end side, the heat received by the convex portion is difficult to transfer to other parts of the ground electrode, and heat is easily stored. .. According to the above configuration, since the second core portion having superior thermal conductivity to the base material extends to the convex portion, it is possible to further suppress the convex portion from being overheated.
以上のように、本発明のスパークプラグによれば、温度低減効果の確保と、凸部を形成する際の意図しない部位の変形の抑制とを両立させることができる。 As described above, according to the spark plug of the present invention, it is possible to both secure the temperature reducing effect and suppress the deformation of the unintended portion when forming the convex portion.
以下、図面を参照しつつ、本発明の実施の形態について説明する。以下の説明では、同一の部材には同一の符号を付してある。それらの名称および機能も同じである。したがって、それらについての詳細な説明は繰り返さない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same members are designated by the same reference numerals. Their names and functions are the same. Therefore, the detailed description of them will not be repeated.
〔第１実施形態〕
本実施形態では、スパークプラグ１の構成について説明する。
[First Embodiment]
In this embodiment, the configuration of the spark plug 1 will be described.
（スパークプラグの構成）
先ず、スパークプラグ１の全体構成について、図１を参照しながら説明する。スパークプラグ１は、絶縁体５０および主体金具３０を備えている。
(Spark plug configuration)
First, the overall configuration of the spark plug 1 will be described with reference to FIG. The spark plug 1 includes an insulator 50 and a main metal fitting 30.
絶縁体５０は、スパークプラグ１の長手方向に延びる略円筒形状の部材である。絶縁体５０は、絶縁性、耐熱性、および熱伝導性に優れた材料で形成されている。例えば、絶縁体５０は、アルミナ系セラミックなどで形成されている。絶縁体５０の一方の端部（先端部）５１には、中心電極２１が設けられている。また、絶縁体の他方の端部（後端部）には、端子金具５２が取り付けられている。 The insulator 50 is a substantially cylindrical member extending in the longitudinal direction of the spark plug 1. The insulator 50 is made of a material having excellent insulation, heat resistance, and thermal conductivity. For example, the insulator 50 is made of an alumina-based ceramic or the like. A center electrode 21 is provided at one end (tip) 51 of the insulator 50. Further, a terminal fitting 52 is attached to the other end (rear end) of the insulator.
中心電極２１は、その先端部（電極先端部２２）が絶縁体５０の先端部５１から突出した状態で、絶縁体５０の軸孔に保持されている。中心電極２１は、電極先端部２２が略円筒形状の絶縁体５０の軸線上に位置するように、絶縁体５０に対して取り付けられている。中心電極２１は略円柱形状を有しており、その先端部分は、電極先端部２２へ向かってテーパ状に縮径している。電極先端部２２は、縮径された中心電極２１の先端部分と同径の略円柱形状を有している。なお、電極先端部２２は、略円柱形状に限定はされず、例えば、四角形、五角形、八角形などの多角形の角柱形状を有していてもよい。 The center electrode 21 is held in the shaft hole of the insulator 50 with its tip (electrode tip 22) protruding from the tip 51 of the insulator 50. The center electrode 21 is attached to the insulator 50 so that the electrode tip 22 is located on the axis of the substantially cylindrical insulator 50. The center electrode 21 has a substantially cylindrical shape, and the tip portion thereof is tapered toward the electrode tip portion 22 in diameter. The electrode tip portion 22 has a substantially cylindrical shape having the same diameter as the tip portion of the reduced diameter center electrode 21. The electrode tip 22 is not limited to a substantially cylindrical shape, and may have a polygonal prismatic shape such as a quadrangle, a pentagon, or an octagon.
主体金具３０は、内燃機関のネジ穴に固定される略円筒形状の部材である。主体金具３０は、絶縁体５０を部分的に覆うように設けられている。主体金具３０は、例えば、低炭素鋼等の導電性を有する金属材料で形成されている。主体金具３０は、主に、加締め部３１、工具係合部３２、湾曲部３３、座部３４、および胴部３６などを有している。 The main metal fitting 30 is a substantially cylindrical member fixed to a screw hole of an internal combustion engine. The main metal fitting 30 is provided so as to partially cover the insulator 50. The main metal fitting 30 is made of a conductive metal material such as low carbon steel. The main metal fitting 30 mainly has a crimping portion 31, a tool engaging portion 32, a curved portion 33, a seat portion 34, a body portion 36, and the like.
加締め部３１および湾曲部３３は、絶縁体５０に主体金具３０を取り付けるための部位である。工具係合部３２は、内燃機関のネジ穴に主体金具３０を取り付けるときにレンチなどの工具を係合させる部位である。座部３４は、工具係合部３２と胴部３６との間に位置している。スパークプラグ１は、座部３４に環状のガスケットが配置された状態で内燃機関に取り付けられる。
胴部３６は、絶縁体５０の先端部５１側に位置している。スパークプラグ１が内燃機関に取り付けられる際には、胴部３６の外周に形成されたネジ溝（図示せず）が内燃機関のネジ穴に螺合される。
The crimping portion 31 and the curved portion 33 are portions for attaching the main metal fitting 30 to the insulator 50. The tool engaging portion 32 is a portion for engaging a tool such as a wrench when attaching the main metal fitting 30 to the screw hole of the internal combustion engine. The seat portion 34 is located between the tool engaging portion 32 and the body portion 36. The spark plug 1 is attached to the internal combustion engine with an annular gasket arranged on the seat 34.
The body portion 36 is located on the tip end portion 51 side of the insulator 50. When the spark plug 1 is attached to the internal combustion engine, a screw groove (not shown) formed on the outer periphery of the body portion 36 is screwed into a screw hole of the internal combustion engine.
また、主体金具３０の先端部側（胴部３６が位置する側）には、接地電極１１が取り付けられている。接地電極１１は、全体が略Ｌ字形に屈曲する板状体で、基端部１１ｂが主体金具３０の先端面に接合固定されている。接地電極１１の先端部１１ａは、絶縁体５０の軸線が通過する位置にまで延びている。そして、接地電極１１の先端部１１ａの近傍には、中心電極２１側に向かって突出する凸部１２が形成されている。 Further, a ground electrode 11 is attached to the tip end side (the side where the body portion 36 is located) of the main metal fitting 30. The ground electrode 11 is a plate-like body that bends in a substantially L shape as a whole, and the base end portion 11b is joined and fixed to the tip surface of the main metal fitting 30. The tip portion 11a of the ground electrode 11 extends to a position where the axis of the insulator 50 passes. A convex portion 12 projecting toward the center electrode 21 side is formed in the vicinity of the tip end portion 11a of the ground electrode 11.
中心電極２１は、例えば、Ｎｉ（すなわち、ニッケル）を主成分として含むＮｉ基合金等の金属材料を母材として構成される。Ｎｉ基合金に添加される合金元素としては、Ａｌ（すなわち、アルミニウム）等が挙げられる。 The center electrode 21 is composed of, for example, a metal material such as a Ni-based alloy containing Ni (that is, nickel) as a main component as a base material. Examples of the alloying element added to the Ni-based alloy include Al (that is, aluminum) and the like.
中心電極２１の電極先端部２２は、例えば、円柱状に成形された貴金属チップにて構成することができ、溶接等により中心電極２１の先端に接合される。 The electrode tip portion 22 of the center electrode 21 can be formed of, for example, a noble metal chip formed into a columnar shape, and is joined to the tip of the center electrode 21 by welding or the like.
（接地電極の構成）
続いて、接地電極１１のより具体的な構成について説明する。図２には、図１に示すスパークプラグの接地電極の先端部１１ａ近傍の拡大断面を示す。
(Structure of ground electrode)
Subsequently, a more specific configuration of the ground electrode 11 will be described. FIG. 2 shows an enlarged cross section in the vicinity of the tip portion 11a of the ground electrode of the spark plug shown in FIG.
接地電極１１は、母材１４と、母材１４に覆われた芯部１５で構成されている。なお、本実施形態では、芯部１５の基端は、主体金具３０の先端面に接合されている。（図示せず）。 The ground electrode 11 is composed of a base material 14 and a core portion 15 covered with the base material 14. In this embodiment, the base end of the core portion 15 is joined to the tip surface of the main metal fitting 30. (Not shown).
母材１４は、例えば、Ｎｉ（すなわち、ニッケル）を主成分として含むＮｉ基合金等の金属材料によって形成されている。Ｎｉ基合金に添加される合金元素としては、Ａｌ（すなわち、アルミニウム）等が挙げられる。 The base material 14 is formed of, for example, a metal material such as a Ni-based alloy containing Ni (that is, nickel) as a main component. Examples of the alloying element added to the Ni-based alloy include Al (that is, aluminum) and the like.
本実施形態では、接地電極１１の凸部１２は、接地電極１１の母材１４一部を、例えば、円柱状、円錐台状、角柱状、又は角錐台状に突出させることによって形成される。すなわち、接地電極１１と一体的に構成される。凸部１２は、後述するように、押出加工によって形成される。この押出工程において、接地電極１１における凸部と反対側の部分に凹部１３が形成される。 In the present embodiment, the convex portion 12 of the ground electrode 11 is formed by projecting a part of the base material 14 of the ground electrode 11 into a truncated cone, a truncated cone, a truncated cone, or a truncated cone, for example. That is, it is integrally formed with the ground electrode 11. The convex portion 12 is formed by extrusion processing as described later. In this extrusion step, a concave portion 13 is formed in a portion of the ground electrode 11 opposite to the convex portion.
凸部１２の径ｄ及び突出高さｈは、対向する中心電極２１の電極先端部２２の径及び突出高さに応じて、所望の放電特性が得られるように、適宜設定することができる。このとき、凸部１２と、中心電極２１の電極先端部２２との間において、所定の火花放電ギャップが形成される。 The diameter d and the protruding height h of the convex portion 12 can be appropriately set so as to obtain desired discharge characteristics according to the diameter and the protruding height of the electrode tip portion 22 of the opposing center electrodes 21. At this time, a predetermined spark discharge gap is formed between the convex portion 12 and the electrode tip portion 22 of the center electrode 21.
また、本実施形態において、凸部１２の突出量と、凹部１３の深さＨと、の関係は、Ｈ＞ｈであり、凸部１２の直径ｄと、凹部１３の直径Ｄと、の関係は、Ｄ＞ｄとなる。凹部１３の体積は、凸部１２の体積よりも大きいが、これは、凸部１２を形成する際に、接地電極１１の一部がどうしても凸部以外の部分に広がってしまうためである。よって、例えば、接地電極１１の軸方向に直交する断面を限りなく矩形形状とする等、凸部１２以外の部分への拡がりを抑制することが好ましい。 Further, in the present embodiment, the relationship between the protrusion amount of the convex portion 12 and the depth H of the concave portion 13 is H> h, and the relationship between the diameter d of the convex portion 12 and the diameter D of the concave portion 13. Is D> d. The volume of the concave portion 13 is larger than the volume of the convex portion 12, because when the convex portion 12 is formed, a part of the ground electrode 11 inevitably expands to a portion other than the convex portion. Therefore, for example, it is preferable to suppress the spread to a portion other than the convex portion 12 by making the cross section of the ground electrode 11 orthogonal to the axial direction infinitely rectangular.
芯部１５は、接地電極１１の延設方向と略同一方向に延び、母材１４に覆われており、第１の芯部１６と、第１の芯部１６に覆われた第２の芯部１７から構成されている。なお、本実施形態において、延設方向とは、図２の矢印で示す方向である。ここで、第１の芯部１６は、例えば、接地電極の延設方向に延びる略円筒形をなしており、熱伝導率の高いＣｕ（すなわち、銅）や、Ｃｕを主成分として含むＣｕ基合金等の金属材料によって形成されている。第２の芯部１７は、例えば、純ＮｉやＮｉを主成分とし、母材１４よりもＮｉの含有率が大きい金属材料等によって形成されている。また、第２の芯部１７は、第１の芯部１６から突出した先端部１７ａと、第１の芯部１６に外周を覆われた内包部１７ｂからなる。先端部１７ａは、略円錐体形状をなしており、その基端は第１の芯部１６の先端面を覆っている。内包部１７ｂは、略円柱形状をなしている。 The core portion 15 extends in substantially the same direction as the extension direction of the ground electrode 11, and is covered with the base material 14, and the first core portion 16 and the second core covered with the first core portion 16 It is composed of a part 17. In the present embodiment, the extension direction is the direction indicated by the arrow in FIG. Here, the first core portion 16 has, for example, a substantially cylindrical shape extending in the extending direction of the ground electrode, and has a high thermal conductivity of Cu (that is, copper) or a Cu group containing Cu as a main component. It is made of a metal material such as an alloy. The second core portion 17 is formed of, for example, a metal material containing pure Ni or Ni as a main component and having a higher Ni content than the base material 14. Further, the second core portion 17 is composed of a tip portion 17a protruding from the first core portion 16 and an inclusion portion 17b whose outer circumference is covered by the first core portion 16. The tip portion 17a has a substantially conical shape, and the base end thereof covers the tip surface of the first core portion 16. The inclusion portion 17b has a substantially cylindrical shape.
接地電極１１は、一般に熱伝導性に優れるＣｕ基合金等によって形成される第１の芯部を備えるので、接地電極１１の過熱を抑制することができる。さらに、接地電極１１は、Ｃｕ基合金よりもビッカース硬度の高いＮｉやＮｉ基合金によって形成される第２の芯部を備えるので、凸部を形成する押出工程の際、接地電極１１のうち意図しない部分が変形することを抑制できる。また、本実施形態において、第２の芯部１７は、第１の芯部１６の主成分であるＣｕと比べて、主体金具３０との接合性が良いＮｉを主成分とし、接地電極１１の基端まで延びているので、主体金具３０の先端面に接地電極１１を溶接する際に接合強度を向上することができる。さらに、第２の芯部１７は、母材１４と同様にＮｉを主成分としているので、母材１４と熱膨張率が近い値となっており、加熱・冷却のサイクルの中で、各部材が膨張・収縮を繰り返した後でも少なくとも先端部１７ａでは母材１４との間に隙間が形成されることを抑制できる。 Since the ground electrode 11 includes a first core portion generally formed of a Cu-based alloy or the like having excellent thermal conductivity, overheating of the ground electrode 11 can be suppressed. Further, since the ground electrode 11 includes a second core portion formed of Ni or a Ni-based alloy having a Vickers hardness higher than that of the Cu-based alloy, it is intended among the ground electrodes 11 during the extrusion step of forming the convex portion. It is possible to suppress the deformation of the non-deformed part. Further, in the present embodiment, the second core portion 17 contains Ni as the main component, which has better bondability with the main metal fitting 30 than Cu, which is the main component of the first core portion 16, and the ground electrode 11 is used. Since it extends to the base end, the joint strength can be improved when the ground electrode 11 is welded to the tip surface of the main metal fitting 30. Further, since the second core portion 17 contains Ni as a main component as in the base metal 14, the coefficient of thermal expansion is close to that of the base metal 14, and each member is in the heating / cooling cycle. It is possible to suppress the formation of a gap between the tip portion 17a and the base material 14 even after the expansion and contraction are repeated.
ビッカース硬度の測定は、例えば、ＪＩＳ Ｚ２２４４：２００９に準じて実行される。まず、接地電極１１を、スパークプラグの軸線を通り、接地電極１１の延設方向に略平行な平面で切断し、一方の切断面を鏡面研磨する。その後、第１の芯部１６、第２の芯部１７それぞれにおいて、厚さ方向の中心を通る線上の任意の点でビッカース硬度が測定される。 The measurement of Vickers hardness is performed according to, for example, JIS Z2244: 2009. First, the ground electrode 11 is cut on a plane that passes through the axis of the spark plug and is substantially parallel to the extending direction of the ground electrode 11, and one of the cut surfaces is mirror-polished. After that, in each of the first core portion 16 and the second core portion 17, the Vickers hardness is measured at an arbitrary point on the line passing through the center in the thickness direction.
本実施形態では、第１の芯部１６の先端は、凹部１３よりも基端側に位置する。これにより、前述のように融点の低い第１の芯部１６が凹部１３の表面に第１の芯部１６が露出し、熱負荷の厳しい環境で融解することを抑制できる。 In the present embodiment, the tip of the first core 16 is located closer to the base than the recess 13. As a result, as described above, the first core portion 16 having a low melting point can be prevented from being melted in an environment where the heat load is severe because the first core portion 16 is exposed on the surface of the recess 13.
本実施形態では、第２の芯部１７の先端は、凹部１３よりも基端側に位置する。これにより、一般に芯部１５より耐酸化性に優れる母材１４のうち、凹部１３表面に第２の芯部１７が露出し、熱負荷の厳しい環境で酸化することを抑制できる。 In the present embodiment, the tip of the second core 17 is located closer to the base than the recess 13. As a result, among the base material 14 which is generally more excellent in oxidation resistance than the core portion 15, the second core portion 17 is exposed on the surface of the recess 13, and oxidation can be suppressed in an environment with a severe heat load.
（製造方法）
続いて、スパークプラグ１の製造方法について説明する。なお、本実施形態にかかるスパークプラグ１を製造するにあたって、接地電極１１における凸部１２を形成するための各工程以外の製造方法については、従来公知のスパークプラグ１の製造方法を適用することができる。そのため、以下では、凸部１２を形成する具体的な方法について説明する。
(Production method)
Subsequently, a method of manufacturing the spark plug 1 will be described. In manufacturing the spark plug 1 according to the present embodiment, a conventionally known manufacturing method of the spark plug 1 may be applied to a manufacturing method other than each step for forming the convex portion 12 on the ground electrode 11. it can. Therefore, a specific method for forming the convex portion 12 will be described below.
図３には、スパークプラグ１の製造方法において、凸部１２を形成する各工程を（１）、（２）に順に示す。（１）に示す工程は準備工程であり、（２）に示す工程は押出工程である。 FIG. 3 shows (1) and (2) in order each step of forming the convex portion 12 in the method of manufacturing the spark plug 1. The step shown in (1) is a preparatory step, and the step shown in (2) is an extrusion step.
（１）の準備工程では、図３（ａ）に示すごとく、接地電極１１の母材１４を、略円柱形の凸部形成用キャビティ６０ａを有する金型６０の上に載置する。このとき、接地電極１１は、金型６０の側面６０ｂに自身の先端部１１ａを当接させた状態で載置される。 In the preparatory step of (1), as shown in FIG. 3A, the base material 14 of the ground electrode 11 is placed on a mold 60 having a substantially cylindrical convex portion forming cavity 60a. At this time, the ground electrode 11 is placed in a state where its tip portion 11a is in contact with the side surface 60b of the mold 60.
また、金型６０には、凸部用キャビティ６０ａに対して摺動可能な可動型６１が挿入配置されている。該可動型６１は、接地電極１１に対向する型面６１ａを形成してなる。なお、凸部用キャビティ６０ａ内に置ける可動型６１の位置を調整することによって凸部１２の突出量ｈを変更することができる。 Further, in the mold 60, a movable mold 61 slidable with respect to the convex cavity 60a is inserted and arranged. The movable mold 61 forms a mold surface 61a facing the ground electrode 11. The protrusion amount h of the convex portion 12 can be changed by adjusting the position of the movable mold 61 that can be placed in the convex portion cavity 60a.
また、押圧治具６２は、凸部用キャビティ６０ａと同様、略円柱形からなるとともに、押圧治具６２の可動方向に直交する断面の断面積が凸部用キャビティ６０ａの断面積よりも大きくなるように構成されている。 Further, the pressing jig 62 has a substantially cylindrical shape like the convex cavity 60a, and the cross-sectional area of the cross section orthogonal to the movable direction of the pressing jig 62 is larger than the cross-sectional area of the convex cavity 60a. It is configured as follows.
（２）の押出工程では、金型６０を用いて、平板上の母材１４に冷間鍛造加工を施すことにより凸部１２を形成する。また、具体的には、図３（ｂ）に示すごとく、押圧治具６２によって接地電極１１のうち、凸部１２が形成される予定の面とは、反対側の面の一部を押圧して凹部１３を形成するとともに接地電極の一部を凸部用キャビティ６０ａに押し出すことにより凸部１２を形成する。 In the extrusion step (2), the convex portion 12 is formed by cold forging the base material 14 on the flat plate using the mold 60. Specifically, as shown in FIG. 3B, the pressing jig 62 presses a part of the surface of the ground electrode 11 opposite to the surface on which the convex portion 12 is to be formed. The convex portion 12 is formed by forming the concave portion 13 and extruding a part of the ground electrode into the convex portion cavity 60a.
また、押圧冶具６２によって接地電極背面１１の一部を押し出すにあたっては、図３（ｂ）に示すごとく、接地電極１１は、金型６０の側面６０ｂに当接したままの状態で押圧治具６２によって、押圧される。したがって、接地電極１１の一部を押し出した分、凸部１２を充分に突出させることができる。ただし、上述したごとく、押圧冶具６２によって押し出された凹部１３の体積分のすべてが凸部１２とはならない場合があるため、接地電極１１の軸方向に直交する断面を限りなく矩形形状とするとともに接地電極１１を金型６０の側面６０ｂに充分に当接させることが好ましい。すなわち、上記方法によれば、凹部１３の体積と凸部１２の体積とを略同等に近付けることができる。
また、凸部１２の頂面は、接地電極１１の一部が可動型６１の型面６１ａに当接することによって成形される。
Further, when pushing out a part of the back surface 11 of the ground electrode by the pressing jig 62, as shown in FIG. 3 (b), the ground electrode 11 remains in contact with the side surface 60b of the mold 60 and is in contact with the pressing jig 62. Is pressed by. Therefore, the convex portion 12 can be sufficiently projected by the amount of pushing out a part of the ground electrode 11. However, as described above, since not all of the volume of the concave portion 13 extruded by the pressing jig 62 may be the convex portion 12, the cross section orthogonal to the axial direction of the ground electrode 11 is made infinitely rectangular. It is preferable that the ground electrode 11 is sufficiently brought into contact with the side surface 60b of the mold 60. That is, according to the above method, the volume of the concave portion 13 and the volume of the convex portion 12 can be brought close to each other substantially.
Further, the top surface of the convex portion 12 is formed by a part of the ground electrode 11 coming into contact with the mold surface 61a of the movable mold 61.
〔第２実施形態〕
本実施形態では、第１実施形態とは、接地電極の構成が異なっているスパークプラグ１について説明する。
[Second Embodiment]
In the present embodiment, the spark plug 1 having a different structure of the ground electrode from the first embodiment will be described.
図４に第２実施形態として示すように、第１の芯部１６の先端と第２の芯部１７の先端とは、凹部１３のうち、接地電極１１の先端側の端１３ａよりも先端側に位置してもよい。基端側薄肉部１４ａや先端側薄肉部１４ｂは、凹部１３が形成されているために他の部位より肉厚が薄くなっている。これにより、接地電極１１の他の部位と比べて熱伝導の経路が狭く、蓄熱されやすい。さらに、先端側薄肉部１４ｂについては、先端部１１ａ方向に端面を有するために表面積が大きくなっており、周囲から熱を吸収しやすい。一般に第１の芯部１６と第２の芯部１７とは、母材よりも熱伝導性に優れるため、上述のように熱が蓄積しやすい基端側薄肉部１４ａや、先端側薄肉部１４ｂが過熱することを抑制できる。また、凸部１２は、基端側薄肉部１４ａと、先端側薄肉部１４ｂの間に配置されているために熱伝導の経路が狭くなっており、蓄熱されやすい。よって、第１の芯部１６と第２の芯部１７とが凸部１２内に存在するので、上述のように熱が蓄積しやすい凸部１２が過熱することを抑制できる。 As shown in FIG. 4 as a second embodiment, the tip of the first core portion 16 and the tip of the second core portion 17 are located on the tip side of the recess 13 on the tip side of the tip side of the ground electrode 11. It may be located in. The base end side thin wall portion 14a and the tip end side thin wall portion 14b are thinner than other portions because the recess 13 is formed. As a result, the heat conduction path is narrower than that of other parts of the ground electrode 11, and heat is easily stored. Further, the thin-walled portion 14b on the tip side has an end face in the direction of the tip portion 11a, so that the surface area is large, and heat is easily absorbed from the surroundings. In general, the first core portion 16 and the second core portion 17 are superior in thermal conductivity to the base material, and therefore, as described above, the base end side thin wall portion 14a and the tip end side thin wall portion 14b where heat is likely to be accumulated Can be suppressed from overheating. Further, since the convex portion 12 is arranged between the base end side thin wall portion 14a and the tip end side thin wall portion 14b, the heat conduction path is narrow and heat is easily stored. Therefore, since the first core portion 16 and the second core portion 17 are present in the convex portion 12, it is possible to prevent the convex portion 12, which tends to accumulate heat, from overheating as described above.
なお、上記実施形態の記載内容に限定されず、例えば、次のように実施してもよい。もちろん、以下において例示しない他の応用例、変更例も当然可能である。 The content is not limited to the description of the above embodiment, and may be implemented as follows, for example. Of course, other application examples and modification examples not illustrated below are also possible.
（ａ）上記実施形態では、母材１４の形状として平板状を採用しているが、例えば、接地電極１１の延設方向に延びる略円柱状のものを採用してもよい。 (A) In the above embodiment, the shape of the base material 14 is a flat plate, but for example, a substantially cylindrical shape extending in the extending direction of the ground electrode 11 may be adopted.
（ｂ）上記実施形態では、第１の芯部１６の形状として略円筒形状を採用しているが、例えば、第２の芯部を覆う軸孔を有し、接地電極１１の延設方向に延びる略角柱形状のものを採用してもよい。また、第２の芯部１７についても、第１の芯部１６の軸孔の形状に合わせて略角柱形状のものを採用し、その先端部１７ａを略角錐体形状のものを採用してもよい。 (B) In the above embodiment, a substantially cylindrical shape is adopted as the shape of the first core portion 16, but for example, it has a shaft hole covering the second core portion and is oriented in the extending direction of the ground electrode 11. An extending substantially prismatic shape may be adopted. Further, as for the second core portion 17, even if a substantially prismatic shape is adopted according to the shape of the shaft hole of the first core portion 16 and the tip portion 17a thereof is a substantially pyramidal shape. Good.
（ｃ）上記実施形態では、第１の芯部１６の先端と第２の芯部１７の先端とがともに凹部１３より基端部１１ｂ側、又は凹部の先端部１１ａ側の端より先端部１１ａ側に位置する構成を採用しているが、例えば、第１の芯部１６の先端が凹部１３よりも基端部１１ｂ側に位置し、第２の芯部１７の先端が凹部１３の先端部１１ａ側の端よりも先端部１１ａ側に位置する構成を採用する等、適宜設定することができる。 (C) In the above embodiment, the tip of the first core portion 16 and the tip of the second core portion 17 are both on the base end portion 11b side from the recess 13 or the tip portion 11a from the end on the tip portion 11a side of the recess. A configuration that is located on the side is adopted. For example, the tip of the first core portion 16 is located closer to the base end portion 11b than the recess 13 and the tip of the second core portion 17 is the tip portion of the recess 13. It can be appropriately set, such as adopting a configuration in which the tip portion 11a side is located closer to the tip portion 11a side than the end on the 11a side.
（ｄ）上記実施形態では、第２の芯部１７の先端部１７ａが第１の芯部１６の先端から突出する構成を採用しているが、第１の芯部１６が第２の芯部１７の先端まで完全に覆う構成を採用してもよい。 (D) In the above embodiment, the tip portion 17a of the second core portion 17 projects from the tip of the first core portion 16, but the first core portion 16 is the second core portion. A configuration that completely covers up to the tip of 17 may be adopted.
（ｅ）上記第２実施例では、第１の芯部１６の先端と第２の芯部の先端１７とが凹部１３の先端部１１ａ側の端よりも先端側に位置する構成を採用しているが、例えば、それぞれの先端が凹部１３の先端部１１ａ側の端よりも基端部１１ｂ側で、凹部１３の基端部１１ｂ側の端よりも先端部１１ａ側に位置する構成を採用してもよい。基端側薄肉部１４ａは、熱伝導の経路が狭くなっているために熱が蓄積されやすい。よって、この構成によれば、第１の芯部１６、又は第２の芯部１７が、接地電極の他の部位より蓄熱されやすい基端側薄肉部１４ａまで延びているので、少なくとも基端側薄肉部１４ａが過熱されることを抑制できる。 (E) In the second embodiment, a configuration is adopted in which the tip of the first core portion 16 and the tip 17 of the second core portion are located on the tip side of the recess 13 on the tip end portion 11a side. However, for example, a configuration is adopted in which each tip is located on the base end 11b side of the recess 13 on the tip 11a side and on the tip 11a side of the recess 13 on the base 11b side. You may. Heat is likely to be accumulated in the base end side thin-walled portion 14a because the heat conduction path is narrow. Therefore, according to this configuration, the first core portion 16 or the second core portion 17 extends to the proximal end side thin wall portion 14a where heat is easily stored from other portions of the ground electrode, and thus at least the proximal end side. It is possible to prevent the thin portion 14a from being overheated.
（ｆ）上記第２実施形態では、第１の芯部１６と第２の芯部１７とが凸部１２内に存在しているが、第１の芯部１６と第２の芯部１７の一方、又は両方が凸部内に存在しない構成を採用してもよい。 (F) In the second embodiment, the first core portion 16 and the second core portion 17 exist in the convex portion 12, but the first core portion 16 and the second core portion 17 A configuration may be adopted in which one or both do not exist in the convex portion.
（ｇ）上記実施形態では、凸部１２の表面に貴金属層がない構成を採用したが、例えば、準備工程の際に予め接地電極１１のうち、凸部１２が形成される予定の部位の上に貴金属板を溶接し、その後、押出工程を行うことで凸部１２の表面に貴金属層が形成されている構成を採用してもよい。 (G) In the above embodiment, the configuration in which the noble metal layer is not formed on the surface of the convex portion 12 is adopted, but for example, on the portion of the ground electrode 11 where the convex portion 12 is to be formed in advance during the preparation step. A noble metal plate may be welded to the surface of the convex portion 12 and then an extrusion step may be performed to form a noble metal layer on the surface of the convex portion 12.
１ ：スパークプラグ
１１ ：接地電極
１１ａ：先端部
１２ ：凸部
１３ ：凹部
１３ａ：先端側の端
１４ ：母材
１５ ：芯部
１６ ：第１の芯部
１７ ：第２の芯部
１７ａ：先端部
１７ｂ：内包部
２１ ：中心電極
２２ ：電極先端部
３０ ：主体金具
５０ ：絶縁体
６０ ：金型
６０ａ：凸部用キャビティ
６０ｂ：側面
６１ ：可動型
６１ａ：型面
６２ ：押圧治具
1: Spark plug 11: Ground electrode 11a: Tip portion 12: Convex portion 13: Recessed portion 13a: Tip side end 14: Base material 15: Core portion 16: First core portion 17: Second core portion 17a: Tip Part 17b: Inclusion part 21: Center electrode 22: Electrode tip part 30: Main metal fitting 50: Insulator 60: Mold 60a: Convex part cavity 60b: Side surface 61: Movable mold 61a: Mold surface 62: Pressing jig
Claims (9)
前記中心電極の外周に配置され、前記中心電極を絶縁保持する主体金具と、
前記主体金具に接合される基端部と、前記中心電極と対向する先端部とを有する接地電極と、備え、
前記接地電極の前記先端部は、前記中心電極に向かって突出してなる凸部と、前記凸部とは反対側の部分に、前記中心電極に向かって窪んだ凹部とを有するスパークプラグであって、
前記接地電極は、前記接地電極の延設方向と略同一方向に延びる芯部と、前記芯部を覆う母材と、によって構成され、
前記芯部は、前記母材よりも熱伝導性に優れる第１の芯部と、前記第１の芯部よりもビッカース硬度が大きく、少なくとも一部が前記第１の芯部に覆われた第２の芯部と、からなるスパークプラグ。 With the center electrode
A main metal fitting arranged on the outer periphery of the center electrode and insulatingly holding the center electrode,
A ground electrode having a base end portion joined to the main metal fitting and a tip end portion facing the center electrode is provided.
The tip portion of the ground electrode is a spark plug having a convex portion protruding toward the center electrode and a concave portion recessed toward the center electrode on a portion opposite to the convex portion. ,
The ground electrode is composed of a core portion extending in substantially the same direction as the extension direction of the ground electrode, and a base material covering the core portion.
The core portion has a first core portion having a higher thermal conductivity than the base material and a Vickers hardness larger than that of the first core portion, and at least a part thereof is covered with the first core portion. A spark plug consisting of 2 cores.
前記第１の芯部の先端は、前記凹部より基端側に位置するスパークプラグ。 The spark plug according to claim 1.
The tip of the first core is a spark plug located on the base end side of the recess.
前記第１の芯部の先端は、前記凹部の基端側の端より先端側に位置するスパークプラグ。 The spark plug according to claim 1.
The tip of the first core is a spark plug located closer to the tip than the base end of the recess.
前記第１の芯部の先端は、前記凹部の先端側の端より先端側に位置するスパークプラグ。 The spark plug according to claim 3.
The tip of the first core is a spark plug located closer to the tip than the tip of the recess.
前記第１の芯部が前記凸部内に位置するスパークプラグ。 The spark plug according to claim 3 or 4.
A spark plug in which the first core portion is located in the convex portion.
前記母材は、前記第２の芯部よりも耐酸化性に優れ、
前記第２の芯部は、前記凹部より基端側に位置するスパークプラグ。 The spark plug according to any one of claims 1 to 5.
The base material has better oxidation resistance than the second core portion,
The second core is a spark plug located closer to the base end than the recess.
前記第２の芯部は、前記母材より熱伝導性に優れ、
前記第２の芯部の先端は、前記凹部の基端側の端より先端側に位置するスパークプラグ。 The spark plug according to any one of claims 1 to 5.
The second core portion has better thermal conductivity than the base material and has a higher thermal conductivity.
The tip of the second core is a spark plug located closer to the tip than the base end of the recess.
前記第２の芯部の先端は、前記凹部の先端側の端より先端側に位置するスパークプラグ。 The spark plug according to claim 7.
The tip of the second core is a spark plug located closer to the tip than the tip of the recess.
前記第２の芯部が前記凸部内に位置するスパークプラグ。 The spark plug according to claim 7 or 8.
A spark plug in which the second core portion is located in the convex portion.
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|---|---|---|---|---|
| JPH02295085A (en) * | 1989-05-09 | 1990-12-05 | Ngk Spark Plug Co Ltd | Outer electrode of ignition plug |
| JPH05101869A (en) * | 1991-10-11 | 1993-04-23 | Ngk Spark Plug Co Ltd | Spark plug |
| JP2001351761A (en) * | 2000-04-03 | 2001-12-21 | Denso Corp | Spark plug for internal combustion engine, and method of manufacture |
| JP2013127911A (en) * | 2011-12-19 | 2013-06-27 | Ngk Spark Plug Co Ltd | Spark plug and manufacturing method thereof |
| JP2017183102A (en) * | 2016-03-30 | 2017-10-05 | 株式会社デンソー | Spark plug an manufacturing method for spark plug |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP5101869B2 (en) | 2006-11-15 | 2012-12-19 | 株式会社ディスコ | Wafer processing method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02295085A (en) * | 1989-05-09 | 1990-12-05 | Ngk Spark Plug Co Ltd | Outer electrode of ignition plug |
| JPH05101869A (en) * | 1991-10-11 | 1993-04-23 | Ngk Spark Plug Co Ltd | Spark plug |
| JP2001351761A (en) * | 2000-04-03 | 2001-12-21 | Denso Corp | Spark plug for internal combustion engine, and method of manufacture |
| JP2013127911A (en) * | 2011-12-19 | 2013-06-27 | Ngk Spark Plug Co Ltd | Spark plug and manufacturing method thereof |
| JP2017183102A (en) * | 2016-03-30 | 2017-10-05 | 株式会社デンソー | Spark plug an manufacturing method for spark plug |
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