JP2012256590A - Spark plug - Google Patents

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JP2012256590A
JP2012256590A JP2012093502A JP2012093502A JP2012256590A JP 2012256590 A JP2012256590 A JP 2012256590A JP 2012093502 A JP2012093502 A JP 2012093502A JP 2012093502 A JP2012093502 A JP 2012093502A JP 2012256590 A JP2012256590 A JP 2012256590A
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Prior art keywords
ground electrode
spark plug
metal shell
tip
center electrode
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Takuya Inoue
拓也 井上
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Niterra Co Ltd
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NGK Spark Plug Co Ltd
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Priority to JP2012093502A priority Critical patent/JP2012256590A/en
Priority to CN201210156707.2A priority patent/CN102790358B/en
Publication of JP2012256590A publication Critical patent/JP2012256590A/en
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Abstract

PROBLEM TO BE SOLVED: To provide a spark plug having a low fuel consumption at a low cost.SOLUTION: In the spark plug where the screw diameter of a threaded portion is 14 mm, following relation is satisfied; 0.371X+1.151X-1.005X-9.019X+0.053X+17.782≤0 where 1.0≤X≤4.2, 3.1≤X≤4.0, 1.0≤X≤1.8, when the width is X(mm), the length of the inner side surface is X(mm), and the thickness is X(mm), of a portion from the horizontal surface along the tip of the center electrode out of a ground electrode to the vertical surface along the center electrode side surface on the ground electrode side.

Description

本発明は、自動車用エンジン等の内燃機関に用いられるスパークプラグに関する。   The present invention relates to a spark plug used for an internal combustion engine such as an automobile engine.

従来から、自動車用エンジンなどの内燃機関に取り付けられ、内燃機関の点火に利用されるスパークプラグが知られている。このようなスパークプラグでは、燃費を向上させるため、中心電極と接地電極の放電部分に貴金属チップを取り付けたものが知られている（例えば、特許文献１参照。）。また、接地電極先端を突き出させ着火性を向上させる技術が知られている（例えば、特許文献２参照。）。   Conventionally, a spark plug that is attached to an internal combustion engine such as an automobile engine and used for ignition of the internal combustion engine is known. Such a spark plug is known in which a noble metal tip is attached to a discharge portion of a center electrode and a ground electrode in order to improve fuel consumption (see, for example, Patent Document 1). In addition, a technique for projecting the tip of the ground electrode to improve the ignitability is known (for example, see Patent Document 2).

特許第３７０２８３８号公報Japanese Patent No. 3702838 特開２００９−５４５７９号公報JP 2009-54579 A

上記のように中心電極や接地電極に貴金属チップを取り付けたり、接地電極先端を突き出させた突き出し形状を設けた場合、工数の増加や貴金属チップの材料費等によって、製品のコストが高くなるという問題がある。   When a noble metal tip is attached to the center electrode or the ground electrode as described above, or a protruding shape with the tip of the ground electrode protruding is provided, the cost of the product increases due to an increase in man-hours or a material cost of the noble metal tip. There is.

本発明は、上記従来の事情に対処してなされたものである。本発明は、低コストでかつ燃料消費量の少ないスパークプラグを提供することを目的とする。   The present invention has been made in response to the above-described conventional circumstances. An object of the present invention is to provide a spark plug with low cost and low fuel consumption.

本発明のスパークプラグの一態様は、外周に取り付け用ねじ部が形成された主体金具と、先端部が前記主体金具から突出するように当該主体金具に保持された絶縁碍子と、先端部が前記絶縁碍子から突出するように当該絶縁碍子に保持された中心電極と、前記主体金具の先端部に配設され、自身の先端部が前記中心電極の先端と対向する接地電極とを具備し、前記取り付け用ねじ部のねじ径が１４ｍｍのスパークプラグにおいて、前記接地電極のうち前記中心電極の先端に沿った水平面から前記接地電極側の前記中心電極側面に沿った垂直面までの部分における、幅をＸ１（ｍｍ）、内側面の長さをＸ２（ｍｍ）、厚みをＸ３（ｍｍ）とした時に、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋17.782≦0
但し、1.0≦Ｘ１≦4.2、3.1≦Ｘ２≦4.0、1.0≦Ｘ３≦1.8
であることを特徴とする。 One aspect of the spark plug of the present invention includes a metal shell having a mounting screw portion formed on the outer periphery, an insulator held by the metal shell so that the tip portion protrudes from the metal shell, and the tip portion of the metal shell. A center electrode held by the insulator so as to protrude from the insulator, and a ground electrode disposed at a tip portion of the metal shell, the tip portion of which is opposed to the tip of the center electrode, In the spark plug having a screw diameter of 14 mm for the mounting screw portion, the width of a portion of the ground electrode from a horizontal plane along the tip of the center electrode to a vertical plane along the side surface of the center electrode on the ground electrode side is set. When X 1 (mm), the length of the inner surface is X 2 (mm), and the thickness is X 3 (mm),
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 17.782 ≦ 0
However, 1.0 ≦ X 1 ≦ 4.2, 3.1 ≦ X 2 ≦ 4.0, 1.0 ≦ X 3 ≦ 1.8
It is characterized by being.

本発明のスパークプラグの他の態様は、外周に取り付け用ねじ部が形成された主体金具と、先端部が前記主体金具から突出するように当該主体金具に保持された絶縁碍子と、先端部が前記絶縁碍子から突出するように当該絶縁碍子に保持された中心電極と、前記主体金具の先端部に配設され、自身の先端部が前記中心電極の先端と対向する接地電極とを具備し、前記取り付け用ねじ部のねじ径が１２ｍｍのスパークプラグにおいて、前記接地電極のうち前記中心電極の先端に沿った水平面から前記接地電極側の前記中心電極側面に沿った垂直面までの部分における、幅をＸ１（ｍｍ）、内側面の長さをＸ２（ｍｍ）、厚みをＸ３（ｍｍ）とした時に、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.276≦0
但し、1.0≦Ｘ１≦3.5、2.6≦Ｘ２≦3.5、1.0≦Ｘ３≦1.5
であることを特徴とする。 Another aspect of the spark plug of the present invention includes a metal shell having a mounting screw portion formed on the outer periphery, an insulator held by the metal shell so that the tip portion protrudes from the metal shell, and a tip portion A center electrode held by the insulator so as to protrude from the insulator, and a ground electrode disposed at the tip of the metal shell, the tip of which faces the tip of the center electrode; In a spark plug having a screw diameter of 12 mm for the mounting screw portion, a width of a portion of the ground electrode from a horizontal plane along the tip of the center electrode to a vertical plane along the side of the center electrode on the ground electrode side Is X 1 (mm), the length of the inner surface is X 2 (mm), and the thickness is X 3 (mm),
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.276≤0
However, 1.0 ≦ X 1 ≦ 3.5, 2.6 ≦ X 2 ≦ 3.5, 1.0 ≦ X 3 ≦ 1.5
It is characterized by being.

本発明のスパークプラグのさらに他の態様は、外周に取り付け用ねじ部が形成された主体金具と、先端部が前記主体金具から突出するように当該主体金具に保持された絶縁碍子と、先端部が前記絶縁碍子から突出するように当該絶縁碍子に保持された中心電極と、前記主体金具の先端部に配設され、自身の先端部が前記中心電極の先端と対向する接地電極とを具備し、前記取り付け用ねじ部のねじ径が１０ｍｍのスパークプラグにおいて、前記接地電極のうち前記中心電極の先端に沿った水平面から前記接地電極側の前記中心電極側面に沿った垂直面までの部分における、幅をＸ１（ｍｍ）、内側面の長さをＸ２（ｍｍ）、厚みをＸ３（ｍｍ）とした時に、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋17.842≦0
但し、1.0≦Ｘ１≦2.5、2.35≦Ｘ２≦3.15、1.0≦Ｘ３≦1.175
であることを特徴とする。 Still another aspect of the spark plug of the present invention includes a metal shell having a mounting screw portion formed on the outer periphery thereof, an insulator held by the metal shell so that the tip portion protrudes from the metal shell, and a tip portion A center electrode held by the insulator so that it protrudes from the insulator, and a ground electrode disposed at the tip of the metal shell, the tip of which is opposed to the tip of the center electrode. In the spark plug having a screw diameter of 10 mm for the mounting screw portion, in the portion from the horizontal plane along the tip of the center electrode to the vertical plane along the side surface of the center electrode on the ground electrode side of the ground electrode. When the width is X 1 (mm), the length of the inner surface is X 2 (mm), and the thickness is X 3 (mm),
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 17.842 ≦ 0
However, 1.0 ≦ X 1 ≦ 2.5, 2.35 ≦ X 2 ≦ 3.15, 1.0 ≦ X 3 ≦ 1.175
It is characterized by being.

上記構成の本発明のスパークプラグでは、取り付け用ねじ部のねじ径が１４ｍｍのスパークプラグにおいて、接地電極のうち中心電極の先端に沿った水平面から接地電極側の中心電極側面に沿った垂直面までの部分における、幅をＸ１（ｍｍ）、内側面の長さをＸ２（ｍｍ）、厚みをＸ３（ｍｍ）とした時に、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋17.782≦0
但し、1.0≦Ｘ１≦4.2、3.1≦Ｘ２≦4.0、1.0≦Ｘ３≦1.8
となっている。 In the spark plug of the present invention having the above-described configuration, in the spark plug having a screw diameter of the mounting screw portion of 14 mm, from the horizontal plane along the tip of the center electrode of the ground electrode to the vertical plane along the side of the center electrode on the ground electrode side When the width is X 1 (mm), the length of the inner surface is X 2 (mm), and the thickness is X 3 (mm),
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 17.782 ≦ 0
However, 1.0 ≦ X 1 ≦ 4.2, 3.1 ≦ X 2 ≦ 4.0, 1.0 ≦ X 3 ≦ 1.8
It has become.

また、ねじ径が１２ｍｍのスパークプラグでは、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.276≦0
但し、1.0≦Ｘ１≦3.5、2.6≦Ｘ２≦3.5、1.0≦Ｘ３≦1.5
となっている。さらに、ねじ径が１０ｍｍのスパークプラグでは、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋17.842≦0
但し、1.0≦Ｘ１≦2.5、2.35≦Ｘ２≦3.15、1.0≦Ｘ３≦1.175
となっている。 Moreover, in a spark plug with a screw diameter of 12 mm,
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.276≤0
However, 1.0 ≦ X 1 ≦ 3.5, 2.6 ≦ X 2 ≦ 3.5, 1.0 ≦ X 3 ≦ 1.5
It has become. Furthermore, in a spark plug with a screw diameter of 10 mm,
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 17.842 ≦ 0
However, 1.0 ≦ X 1 ≦ 2.5, 2.35 ≦ X 2 ≦ 3.15, 1.0 ≦ X 3 ≦ 1.175
It has become.

上記の接地電極の幅Ｘ１が広すぎると、着火した際の火炎からの熱引きが強すぎて火炎の成長を妨げ（消炎効果）、着火性が低下する。また、着火後火炎が伝播する際、接地電極の幅Ｘ１が広いと火炎伝播も阻害され燃焼がスムーズに進行せず、燃焼速度の低下につながる。しかし、接地電極の幅Ｘ１がある程度細くなるとそれ以上細くしても着火性、燃焼速度の向上は頭打ちとなり、電極の消耗が加速されてしまう。 If the width X 1 of the ground electrode is too large, heat dissipation is too strong hinder the growth of the flame (anti-inflammatory effect) from the flame when ignited, the ignition may be lowered. Further, when the post-ignition flame propagates, it is also inhibited flame propagation and wider width X 1 of the ground electrode combustion does not proceed smoothly, leading to a decrease in the burning rate. However, ignitability be thin more when the width X 1 of the ground electrode becomes somewhat thinner, enhancing the combustion rate becomes plateau, consumption of the electrode from being accelerated.

上記の接地電極の内側部分の長さＸ２が短すぎるとそれだけ接地電極が中心電極に近付く形になり、上記の接地電極の幅Ｘ１と同様に、着火性、燃焼速度の低下につながる。接地電極の厚みＸ３も上記の接地電極の幅Ｘ１と同様に、厚すぎると着火性、燃焼速度の低下につながる。しかし、ある程度薄くなるとそれ以上薄くしても着火性、燃焼速度の向上は頭打ちとなる。 Much ground electrode when the length X 2 of the inner portion of the ground electrode is too short is in the form closer to the center electrode, as well as the width X 1 of the ground electrode, ignitability, leads to a decrease in burning rate. Similar to the width X 1 of the thickness X 3 also above the ground electrode of the ground electrode, too thick ignitability, it leads to a decrease in burning rate. However, if the thickness is reduced to some extent, the improvement in ignitability and combustion speed will reach its peak even if the thickness is further reduced.

接地電極の幅Ｘ１、接地電極の内側部分の長さＸ２、接地電極の厚みＸ３は、それぞれ単独で、着火性及び燃焼速度と、耐久性とのトレードオフになっており、また、Ｘ１、Ｘ２、Ｘ３がお互いに、着火性及び燃焼速度と、耐久性に影響を及ぼす。Ｘ１、Ｘ２、Ｘ３が上記の関係を満たすことによって、耐久性を犠牲にすることなく、低コストでかつ燃料消費量の少ないスパークプラグを提供することができる。 The width X 1 of the ground electrode, the length X 2 of the inner portion of the ground electrode, and the thickness X 3 of the ground electrode are each independently a trade-off between ignitability, combustion speed, and durability. X 1 , X 2 , X 3 influence each other on ignitability, combustion speed, and durability. When X 1 , X 2 , and X 3 satisfy the above relationship, it is possible to provide a spark plug with low cost and low fuel consumption without sacrificing durability.

また、ねじ径が１４ｍｍのスパークプラグでは、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋18.082≦0
但し、1.0≦Ｘ１≦4.2、3.1≦Ｘ２≦4.0、1.0≦Ｘ３≦1.8
ねじ径が１２ｍｍのスパークプラグでは、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.476≦0
但し、1.0≦Ｘ１≦3.5、2.6≦Ｘ２≦3.5、1.0≦Ｘ３≦1.5
ねじ径が１０ｍｍのスパークプラグでは、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋18.042≦0
但し、1.0≦Ｘ１≦2.5、2.35≦Ｘ２≦3.15、1.0≦Ｘ３≦1.175
とすることにより、さらに燃料消費量の少ないスパークプラグを提供することができる。 Moreover, in the spark plug having a screw diameter of 14 mm,
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 18.082 ≦ 0
However, 1.0 ≦ X 1 ≦ 4.2, 3.1 ≦ X 2 ≦ 4.0, 1.0 ≦ X 3 ≦ 1.8
For spark plugs with a screw diameter of 12 mm,
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.476 ≦ 0
However, 1.0 ≦ X 1 ≦ 3.5, 2.6 ≦ X 2 ≦ 3.5, 1.0 ≦ X 3 ≦ 1.5
For spark plugs with a screw diameter of 10 mm,
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 18.042≤0
However, 1.0 ≦ X 1 ≦ 2.5, 2.35 ≦ X 2 ≦ 3.15, 1.0 ≦ X 3 ≦ 1.175
By doing so, it is possible to provide a spark plug that consumes less fuel.

本発明によれば、低コストでかつ燃料消費量の少ないスパークプラグを提供することができる。   According to the present invention, it is possible to provide a spark plug with low cost and low fuel consumption.

本発明の一実施形態に係るスパークプラグの全体概略構成を示す図。The figure which shows the whole schematic structure of the spark plug which concerns on one Embodiment of this invention. 図１のスパークプラグの要部構成を拡大して示す図。The figure which expands and shows the principal part structure of the spark plug of FIG. 図１のスパークプラグの要部構成を拡大して示す図。The figure which expands and shows the principal part structure of the spark plug of FIG. 図１のスパークプラグの要部構成を拡大して示す図。The figure which expands and shows the principal part structure of the spark plug of FIG. 図１のスパークプラグの要部構成を拡大して示す図。The figure which expands and shows the principal part structure of the spark plug of FIG. 図１のスパークプラグの要部構成を拡大して示す図。The figure which expands and shows the principal part structure of the spark plug of FIG. 変形例のスパークプラグの要部構成を拡大して示す図。The figure which expands and shows the principal part structure of the spark plug of a modification. 変形例のスパークプラグの要部構成を拡大して示す図。The figure which expands and shows the principal part structure of the spark plug of a modification.

以下、本発明の詳細を、図面を参照して実施形態について説明する。   Hereinafter, details of the present invention will be described with reference to the drawings.

図１は、本発明の一実施形態にかかるスパークプラグ１００の全体概略構成を示す図であり、図２はスパークプラグ１００の要部構成を拡大して示す図である。以下、スパークプラグ１００の軸線Ｏ方向を図面における上下方向とし、下側をスパークプラグ１００の先端側、上側を後端側として説明する。   FIG. 1 is a diagram showing an overall schematic configuration of a spark plug 100 according to an embodiment of the present invention, and FIG. 2 is an enlarged view showing a main configuration of the spark plug 100. In the following description, the axis O direction of the spark plug 100 is the vertical direction in the drawing, the lower side is the front end side of the spark plug 100, and the upper side is the rear end side.

図１に示すように、スパークプラグ１００は、低炭素鋼等の金属により構成され、軸線Ｏ方向に延びる円筒状の主体金具５０を具備している。この主体金具５０の内側には、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先端部１１が主体金具５０の端面から突出する形で配置された絶縁碍子１０が支持されている。   As shown in FIG. 1, the spark plug 100 includes a cylindrical metal shell 50 that is made of a metal such as low carbon steel and extends in the direction of the axis O. On the inside of the metal shell 50, an insulator 10 is supported, which is made of a ceramic sintered body such as alumina or aluminum nitride, and the tip portion 11 is arranged so as to protrude from the end surface of the metal shell 50.

この絶縁碍子１０の軸孔１２内には、先端部２２が絶縁碍子１０の端面から突出するように中心電極２０が配置されている。中心電極２０は、インコネル６００（商標名）、インコネル６０１（商標名）等のニッケル系合金等からなる電極母材の中心部に、放熱促進のための銅、あるいは銅合金などで構成された芯材２３が埋設された棒状の電極である。   In the shaft hole 12 of the insulator 10, the center electrode 20 is disposed so that the tip 22 protrudes from the end surface of the insulator 10. The center electrode 20 has a core made of copper or a copper alloy for promoting heat dissipation at the center of an electrode base material made of a nickel-based alloy such as Inconel 600 (trade name) or Inconel 601 (trade name). This is a rod-shaped electrode in which the material 23 is embedded.

中心電極２０は、絶縁碍子１０の脚長部１３が形成された部分の軸孔１２内に保持されている。また中心電極２０は、軸孔１２の内部に設けられたシール体４および抵抗体３を経由して、後端側胴部１８が形成された部分の軸孔１２内に保持される接続端子４０に電気的に接続されている。接続端子４０の後端部４１は絶縁碍子１０の後端より露出され、この後端部４１に、プラグキャップ（図示せず。）を介して高圧ケーブル（図示せず。）が接続され、高電圧が印加されるようになっている。   The center electrode 20 is held in the shaft hole 12 at the portion where the leg portion 13 of the insulator 10 is formed. The center electrode 20 is connected to the connecting terminal 40 held in the shaft hole 12 in the portion where the rear end side body portion 18 is formed via the seal body 4 and the resistor 3 provided in the shaft hole 12. Is electrically connected. The rear end portion 41 of the connection terminal 40 is exposed from the rear end of the insulator 10, and a high voltage cable (not shown) is connected to the rear end portion 41 via a plug cap (not shown). A voltage is applied.

絶縁碍子１０は、アルミナ等を焼成して形成され、軸線Ｏ方向に軸孔１２を有する筒状の絶縁部材である。軸線Ｏ方向の略中央には外径が最も大きな鍔部１９が形成されており、これより後端側には後端側胴部１８が形成されている。また、鍔部１９より先端側には先端側胴部１７と、その先端側胴部１７に連続する脚長部１３とが形成されている。脚長部１３は先端側ほど縮径されている。   The insulator 10 is a cylindrical insulating member formed by firing alumina or the like and having an axial hole 12 in the direction of the axis O. A flange portion 19 having the largest outer diameter is formed substantially at the center in the direction of the axis O, and a rear end side body portion 18 is formed on the rear end side. Further, a distal end side body portion 17 and a leg long portion 13 continuous with the distal end side body portion 17 are formed on the distal end side from the flange portion 19. The long leg portion 13 is reduced in diameter toward the distal end side.

主体金具５０は、絶縁碍子１０の鍔部１９近傍の後端側胴部１８から、鍔部１９、先端側胴部１７および脚長部１３を取り囲むようにして絶縁碍子１０を保持している。主体金具５０は低炭素鋼材で形成され、六角レンチ等の工具を係合するための工具係合部５１と、内燃機関上部に設けられたエンジンヘッドに螺合するためのねじ部５２とを備えている。このねじ部５２のねじ径は、１４ｍｍ、１２ｍｍ、１０ｍｍの３種類のスパークプラグ１００がある。   The metal shell 50 holds the insulator 10 so as to surround the flange portion 19, the distal end side trunk portion 17, and the leg length portion 13 from the rear end side barrel portion 18 in the vicinity of the flange portion 19 of the insulator 10. The metal shell 50 is formed of a low carbon steel material, and includes a tool engaging portion 51 for engaging a tool such as a hexagon wrench, and a screw portion 52 for screwing into an engine head provided at the upper part of the internal combustion engine. ing. There are three types of spark plugs 100 having a screw diameter of 14 mm, 12 mm, and 10 mm.

また、主体金具５０の工具係合部５１と絶縁碍子１０後端側胴部１８との間には環状のリング部材６，７が配設されており、更に両リング部材６，７の間にはタルク（滑石）９の粉末が充填されている。工具係合部５１の後端側には、かしめ部５３が形成されており、このかしめ部５３をかしめることにより、リング部材６，７およびタルク９を介して絶縁碍子１０が主体金具５０内で先端側に向け押圧される。これにより、主体金具５０の内周に形成された段部５６に、絶縁碍子１０の先端側胴部１７と脚長部１３との間の段部１５が板パッキン８０を介して支持されて、主体金具５０と絶縁碍子１０とが一体にされる。主体金具５０と絶縁碍子１０との間の気密は板パッキン８０によって保持され、燃焼ガスの流出が防止される。また、主体金具５０の中央部には鍔部５４が形成されており、鍔部５４とねじ部５２との間のねじ首部５５には、燃焼室のガス抜けを防止するガスケット５が嵌挿されている。   In addition, annular ring members 6 and 7 are disposed between the tool engaging portion 51 of the metal shell 50 and the insulator 10 rear end side body portion 18, and further between the ring members 6 and 7. Is filled with talc 9 powder. A caulking portion 53 is formed on the rear end side of the tool engaging portion 51, and by caulking the caulking portion 53, the insulator 10 is brought into the metal shell 50 via the ring members 6, 7 and the talc 9. Is pressed toward the tip side. As a result, the step portion 15 formed between the distal end side body portion 17 and the leg length portion 13 of the insulator 10 is supported by the step portion 56 formed on the inner periphery of the metal shell 50 via the plate packing 80, The metal fitting 50 and the insulator 10 are integrated. The airtightness between the metal shell 50 and the insulator 10 is maintained by the plate packing 80, and the outflow of combustion gas is prevented. A flange 54 is formed in the central portion of the metal shell 50, and a gasket 5 that prevents gas escape from the combustion chamber is fitted into a screw neck 55 between the flange 54 and the screw 52. ing.

主体金具５０の先端部には、接地電極３０が溶接により固着されている。接地電極３０は、前述したインコネル６００（商標名）、インコネル６０１（商標名）等によって構成されている。この接地電極３０は、自身の長手方向と直交する横断面が略長方形であり、屈曲された角棒状の外形を呈している。そして、角棒状の基端側の基部３２が、主体金具５０の軸線方向先端側の先端面５７に溶接されている。一方、この接地電極３０の基部３２とは反対側の先端部３１は、中心電極２０の先端部２２に対向するよう屈曲されている。そして、中心電極２０の先端部２２と、接地電極３０の先端部３１との対向部分との間に火花放電ギャップが形成されている。   The ground electrode 30 is fixed to the front end of the metal shell 50 by welding. The ground electrode 30 is configured by the above-described Inconel 600 (trade name), Inconel 601 (trade name), or the like. The ground electrode 30 has a substantially rectangular cross section perpendicular to the longitudinal direction of the ground electrode 30 and has a bent rectangular bar-like outer shape. The base 32 on the base end side in the shape of a square bar is welded to the front end surface 57 on the front end side in the axial direction of the metal shell 50. On the other hand, the tip 31 of the ground electrode 30 opposite to the base 32 is bent so as to face the tip 22 of the center electrode 20. A spark discharge gap is formed between the tip 22 of the center electrode 20 and the portion facing the tip 31 of the ground electrode 30.

本実施形態のスパークプラグ１００では、図２（ａ）に示すように、接地電極３０の、少なくとも中心電極２０の先端部２２の先端（先端面）に沿った水平面（図中点線Ａで示す。）から接地電極側３０側の中心電極２０側面に沿った垂直面（図中点線Ｂで示す。）までの領域（図２（ａ）中斜線を付して示す。）の寸法が、図２（ｂ）に示す接地電極３０の幅をＸ１（ｍｍ）、接地電極３０の内側部分の長さをＸ２（ｍｍ）、接地電極３０の厚みをＸ３（ｍｍ）とした時に、以下のようになっている。なお、前記した接地電極３０の厚みＸ３（ｍｍ）とは、上記した領域（図２（ａ）中斜線を付して示す。）の先端部における垂直面（図中点線Ｂで示す。）にて測定した接地電極３０の厚みを言う。 In the spark plug 100 of the present embodiment, as shown in FIG. 2A, the ground electrode 30 is indicated by a horizontal plane (dotted line A in the figure) along at least the tip (tip surface) of the tip portion 22 of the center electrode 20. ) To the vertical plane (indicated by the dotted line B in the figure) along the side surface of the central electrode 20 on the ground electrode side 30 side, the dimensions of the region (indicated by the oblique lines in FIG. 2A) are shown in FIG. When the width of the ground electrode 30 shown in (b) is X 1 (mm), the length of the inner part of the ground electrode 30 is X 2 (mm), and the thickness of the ground electrode 30 is X 3 (mm), the following It is like that. The thickness X 3 (mm) of the ground electrode 30 described above is a vertical plane (indicated by a dotted line B in the drawing) at the tip of the above-described region (shown by hatching in FIG. 2A). Is the thickness of the ground electrode 30 measured by.

すなわち、ねじ部５２のねじ径が１４ｍｍのスパークプラグ１００では、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋17.782≦0
但し、1.0≦Ｘ１≦4.2、3.1≦Ｘ２≦4.0、1.0≦Ｘ３≦1.8
を満たす範囲の接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）の寸法となっており、さらに好ましくは、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋18.082≦0
但し、1.0≦Ｘ１≦4.2、3.1≦Ｘ２≦4.0、1.0≦Ｘ３≦1.8
を満たす範囲の接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）の寸法となっている。 That is, in the spark plug 100 in which the screw diameter of the screw portion 52 is 14 mm,
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 17.782 ≦ 0
However, 1.0 ≦ X 1 ≦ 4.2, 3.1 ≦ X 2 ≦ 4.0, 1.0 ≦ X 3 ≦ 1.8
The width X 1 (mm) of the ground electrode 30 in a range that satisfies the conditions, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are more preferable. ,
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 18.082 ≦ 0
However, 1.0 ≦ X 1 ≦ 4.2, 3.1 ≦ X 2 ≦ 4.0, 1.0 ≦ X 3 ≦ 1.8
The width X 1 (mm) of the ground electrode 30 in a range that satisfies the conditions, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are measured.

また、ねじ部５２のねじ径が１２ｍｍのスパークプラグ１００では、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.276≦0
但し、1.0≦Ｘ１≦3.5、2.6≦Ｘ２≦3.5、1.0≦Ｘ３≦1.5
を満たす範囲の接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）の寸法となっており、さらに好ましくは、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.476≦0
但し、1.0≦Ｘ１≦3.5、2.6≦Ｘ２≦3.5、1.0≦Ｘ３≦1.5
を満たす範囲の接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）の寸法となっている。 Further, in the spark plug 100 in which the screw diameter of the screw portion 52 is 12 mm,
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.276≤0
However, 1.0 ≦ X 1 ≦ 3.5, 2.6 ≦ X 2 ≦ 3.5, 1.0 ≦ X 3 ≦ 1.5
The width X 1 (mm) of the ground electrode 30 in a range that satisfies the conditions, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are more preferable. ,
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.476 ≦ 0
However, 1.0 ≦ X 1 ≦ 3.5, 2.6 ≦ X 2 ≦ 3.5, 1.0 ≦ X 3 ≦ 1.5
The width X 1 (mm) of the ground electrode 30 in a range that satisfies the conditions, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are measured.

また、ねじ部５２のねじ径が１０ｍｍのスパークプラグ１００では、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋17.842≦0
但し、1.0≦Ｘ１≦2.5、2.35≦Ｘ２≦3.15、1.0≦Ｘ３≦1.175
を満たす範囲の接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）の寸法となっており、さらに好ましくは、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋18.042≦0
但し、1.0≦Ｘ１≦2.5、2.35≦Ｘ２≦3.15、1.0≦Ｘ３≦1.175
を満たす範囲の接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）の寸法となっている。 Further, in the spark plug 100 in which the screw diameter of the screw portion 52 is 10 mm,
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 17.842 ≦ 0
However, 1.0 ≦ X 1 ≦ 2.5, 2.35 ≦ X 2 ≦ 3.15, 1.0 ≦ X 3 ≦ 1.175
The width X 1 (mm) of the ground electrode 30 in a range that satisfies the conditions, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are more preferable. ,
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 18.042≤0
However, 1.0 ≦ X 1 ≦ 2.5, 2.35 ≦ X 2 ≦ 3.15, 1.0 ≦ X 3 ≦ 1.175
The width X 1 (mm) of the ground electrode 30 in a range that satisfies the conditions, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are measured.

次に、本実施形態において、接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）が上記した寸法の範囲内となっている理由について説明する。 Next, in the present embodiment, the width X 1 (mm) of the ground electrode 30, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are within the above dimensions. The reason for the inside will be explained.

排気量が０．６６リットルの３気筒エンジンで、油温８５℃、水温９０℃、回転数８００ｒｐｍの条件で１０分間アイドリングを行った時の燃料消費量を測定した。測定は片方の電極のみにイリジウムチップが固定されたスパークプラグと、両方の電極にイリジウムチップが固定されたスパークプラグについて、ねじ径が１４ｍｍ（Ｍ１４）、１２ｍｍ（Ｍ１２）、１０ｍｍ（Ｍ１０）の場合夫々について測定した。この結果、片方の電極のみにイリジウムチップが固定されてスパークプラグでは、
ねじ径が１４ｍｍ（Ｍ１４）：６２．１ｍｌ
ねじ径が１２ｍｍ（Ｍ１２）：６２．５ｍｌ
ねじ径が１０ｍｍ（Ｍ１０）：６３．１ｍｌ
となった。また両方の電極にイリジウムチップが固定されたスパークプラグでは、
ねじ径が１４ｍｍ（Ｍ１４）：６１．８ｍｌ
ねじ径が１２ｍｍ（Ｍ１２）：６２．３ｍｌ
ねじ径が１０ｍｍ（Ｍ１０）：６２．９ｍｌ
となった。これらの結果を各ねじ径のスパークプラグにおける目標値として、前記した接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）を変更した複数のスパークプラグについて、燃料消費量を測定した。このうち、ねじ径が１４ｍｍ（Ｍ１４）のスパークプラグについての燃料消費量の測定結果を以下の表１に示す。 The fuel consumption was measured when idling for 10 minutes under conditions of an oil temperature of 85 ° C., a water temperature of 90 ° C., and a rotation speed of 800 rpm in a 3-cylinder engine with a displacement of 0.66 liters. Measurement is performed with a spark plug in which an iridium tip is fixed to only one electrode and a spark plug in which an iridium tip is fixed to both electrodes and the screw diameter is 14 mm (M14), 12 mm (M12), or 10 mm (M10). Each was measured. As a result, the iridium tip is fixed to only one of the electrodes, and the spark plug
Screw diameter 14mm (M14): 62.1ml
Screw diameter 12mm (M12): 62.5ml
Screw diameter is 10mm (M10): 63.1ml
It became. In the spark plug with iridium tips fixed to both electrodes,
Screw diameter is 14mm (M14): 61.8ml
Screw diameter is 12mm (M12): 62.3ml
Screw diameter is 10mm (M10): 62.9ml
It became. Using these results as target values for the spark plug of each screw diameter, the width X 1 (mm) of the ground electrode 30, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 of the ground electrode 30. Fuel consumption was measured for a plurality of spark plugs with different (mm). Among these, the measurement results of the fuel consumption for the spark plug having a screw diameter of 14 mm (M14) are shown in Table 1 below.

Figure 2012256590
Figure 2012256590

表１の判定の欄において、生産可能性、耐久性、折損性のいずれかが×の場合は×、生産可能性、耐久性、折損性共に○かつ燃料消費量が６２．１より多い場合は△、生産可能性、耐久性、折損性共に○かつ燃料消費量が６２．１以下で６１．８より多い場合は○、生産可能性、耐久性、折損性共に○かつ燃料消費量が６１．８以下の場合は◎となっている。   In the judgment column of Table 1, if any of the production possibility, durability, and breakability is x, the production possibility, durability, breakability is ○, and the fuel consumption is more than 62.1 △, production feasibility, durability, breakability ○ and fuel consumption is 62.1 or less and more than 61.8, ○, production feasibility, durability, breakability ○, and fuel consumption 61. In the case of 8 or less, it is ◎.

表１のデータから通常のニッケルプラグの燃料消費量を下回るもののデータを使用して重回帰分析を行った。この結果燃料消費量をＹとすると、
Ｙ＝0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋79.882
となる。これが片側貴金属プラグの燃料消費量６２．１ｍｌを下回る寸法を規定すると、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋17.782≦0
となる。更に、両側貴金属プラグの燃料消費量６１．８ｍｌを下回る寸法を規定すると、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋18.082≦0
となる。 Multiple regression analysis was performed using the data of Table 1 below the fuel consumption of normal nickel plugs. As a result, if the fuel consumption is Y,
Y = 0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 +79.882
It becomes. If this stipulates a dimension that is less than 62.1 ml of fuel consumption on one side of the noble metal plug,
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 17.782 ≦ 0
It becomes. Furthermore, if the fuel consumption of the precious metal plugs on both sides is defined to be less than 61.8 ml,
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 18.082 ≦ 0
It becomes.

更に、図３に示すように、主体金具１０１と接地電極３０との位置関係を見た時に、ねじ径が１４ｍｍ（Ｍ１４）の場合、接地電極３０の幅Ｘ１（ｍｍ）が４．２ｍｍを超えると主体金具１０１からはみ出してしまう。また、接地電極３０の幅Ｘ１が１．０ｍｍ未満となると耐久性が不十分になり、折損の虞もある。このため、接地電極３０の幅Ｘ１（ｍｍ）は、
1.0≦Ｘ１≦4.2
の範囲となる。 Furthermore, as shown in FIG. 3, when the positional relationship between the metal shell 101 and the ground electrode 30 is viewed, when the screw diameter is 14 mm (M14), the width X 1 (mm) of the ground electrode 30 is 4.2 mm. If it exceeds, it will protrude from the metal shell 101. Further, the width X 1 of the ground electrode 30 is less than 1.0mm become insufficient durability, there is a possibility of breakage. For this reason, the width X 1 (mm) of the ground electrode 30 is
1.0 ≦ X 1 ≦ 4.2
It becomes the range.

また、接地電極３０の内側部分の長さをＸ２（ｍｍ）については、図４に示すように、ねじ径が１４ｍｍ（Ｍ１４）の場合、接地電極３０が直角に折曲された時が最長となり４．０ｍｍとなる。さらに図５に示すように、接地電極３０の斜線部にＲが全く無い場合が最短となり３．１ｍｍとなる。したがって、接地電極３０の内側部分の長さＸ２は、
3.1≦Ｘ２≦4.0
の範囲となる。 Further, regarding the length of the inner portion of the ground electrode 30 as X 2 (mm), as shown in FIG. 4, when the screw diameter is 14 mm (M14), the longest time when the ground electrode 30 is bent at a right angle is the longest. Becomes 4.0 mm. Further, as shown in FIG. 5, the shortest case where there is no R in the hatched portion of the ground electrode 30 is 3.1 mm. Accordingly, the length X 2 of the inner portion of the ground electrode 30,
3.1 ≦ X 2 ≦ 4.0
It becomes the range.

また、接地電極３０の厚みＸ３（ｍｍ）については、図６に示すように、ねじ径が１４ｍｍ（Ｍ１４）の場合、１．８ｍｍを超えると主体金具１０１からはみ出してしまう。また、接地電極３０の厚みをＸ３が１．０ｍｍ未満となると耐久性が不十分になり、折損の虞もある。このため、接地電極３０の厚みＸ３（ｍｍ）は、
1.0≦Ｘ３≦1.8
の範囲となる。 As for the thickness X 3 (mm) of the ground electrode 30, as shown in FIG. 6, when the screw diameter is 14 mm (M14), the thickness X 3 (mm) protrudes from the metal shell 101 when it exceeds 1.8 mm. Further, the X 3 the thickness of the ground electrode 30 becomes insufficient durability becomes less than 1.0 mm, there is a possibility of breakage. For this reason, the thickness X 3 (mm) of the ground electrode 30 is
1.0 ≦ X 3 ≦ 1.8
It becomes the range.

以上のように、ねじ径が１４ｍｍ（Ｍ１４）のスパークプラグでは、接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）について、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋17.782≦0
さらに好ましくは、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋18.082≦0
但し、1.0≦Ｘ１≦4.2、3.1≦Ｘ２≦4.0、1.0≦Ｘ３≦1.8
とすることによって、貴金属チップを使用したスパークプラグと同等以上の低燃費化を行うことができ、低コストでかつ燃料消費量の少ないスパークプラグを提供することができる。 As described above, in the spark plug having a screw diameter of 14 mm (M14), the width X 1 (mm) of the ground electrode 30, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 of the ground electrode 30. About (mm)
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 17.782 ≦ 0
More preferably,
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 18.082 ≦ 0
However, 1.0 ≦ X 1 ≦ 4.2, 3.1 ≦ X 2 ≦ 4.0, 1.0 ≦ X 3 ≦ 1.8
By doing so, it is possible to reduce fuel consumption equivalent to or higher than that of a spark plug using a noble metal tip, and it is possible to provide a spark plug with low cost and low fuel consumption.

次に、ねじ径が１２ｍｍ（Ｍ１２）のスパークプラグについての燃料消費量の測定結果を以下の表２に示す。   Next, the measurement results of the fuel consumption for the spark plug having a screw diameter of 12 mm (M12) are shown in Table 2 below.

Figure 2012256590
Figure 2012256590

表２の判定の欄において、生産可能性、耐久性、折損性のいずれかが×の場合は×、生産可能性、耐久性、折損性共に○かつ燃料消費量が６２．５より多い場合は△、生産可能性、耐久性、折損性共に○かつ燃料消費量が６２．５以下で６２．３より多い場合は○、生産可能性、耐久性、折損性共に○かつ燃料消費量が６２．３以下の場合は◎となっている。   In the judgment column of Table 2, if any of the production possibility, durability, and breakability is x, the production possibility, durability, breakability is ○, and the fuel consumption is more than 62.5 △, when production possibility, durability and breakability are both ◯ and the fuel consumption is 62.5 or less and more than 62.3, ◯, both production possibility, durability and breakability are ◯ and the fuel consumption is 62. In the case of 3 or less, it is ◎.

表２のデータから通常のニッケルプラグの燃料消費量を下回るもののデータを使用して重回帰分析を行った。この結果燃料消費量をＹとすると、
Ｙ＝0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋70.776
となる。これが片側貴金属プラグの燃料消費量６２．５ｍｌを下回る寸法を規定すると、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.276≦0
となる。更に、両側貴金属プラグの燃料消費量６２．３ｍｌを下回る寸法を規定すると、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.476≦0
となる。 A multiple regression analysis was performed using the data in Table 2 below the fuel consumption of a normal nickel plug. As a result, if the fuel consumption is Y,
Y = 0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 +70.776
It becomes. If this stipulates that the fuel consumption of one side precious metal plug is less than 62.5 ml,
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.276≤0
It becomes. Furthermore, if the fuel consumption of the noble metal plugs on both sides is defined to be less than 62.3 ml,
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.476 ≦ 0
It becomes.

また、前述したねじ径が１４ｍｍ（Ｍ１４）のスパークプラグの場合と同様な理由により、ねじ径が１２ｍｍ（Ｍ１２）のスパークプラグの場合、
1.0≦Ｘ１≦3.5、2.6≦Ｘ２≦3.5、1.0≦Ｘ３≦1.5
となる。 For the same reason as the spark plug having a screw diameter of 14 mm (M14) described above, in the case of a spark plug having a screw diameter of 12 mm (M12),
1.0 ≦ X 1 ≦ 3.5, 2.6 ≦ X 2 ≦ 3.5, 1.0 ≦ X 3 ≦ 1.5
It becomes.

ねじ径が１２ｍｍ（Ｍ１２）のスパークプラグでは、接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）について、上記の条件を満たす範囲内の寸法とすることによって、貴金属チップを使用したスパークプラグと同等以上の低燃費化を行うことができ、低コストでかつ燃料消費量の少ないスパークプラグを提供することができる。 In the spark plug having a screw diameter of 12 mm (M12), the width X 1 (mm) of the ground electrode 30, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are By making the dimensions within the range satisfying the above conditions, it is possible to achieve a fuel consumption equivalent to or higher than that of a spark plug using a noble metal tip, and to provide a spark plug with low cost and low fuel consumption. it can.

次に、ねじ径が１０ｍｍ（Ｍ１０）のスパークプラグについての燃料消費量の測定結果を以下の表３に示す。   Next, the measurement results of the fuel consumption for the spark plug having a screw diameter of 10 mm (M10) are shown in Table 3 below.

Figure 2012256590
Figure 2012256590

表３の判定の欄において、生産可能性、耐久性、折損性のいずれかが×の場合は×、生産可能性、耐久性、折損性共に○かつ燃料消費量が６３．１より多い場合は△、生産可能性、耐久性、折損性共に○かつ燃料消費量が６３．１以下で６２．９より多い場合は○、生産可能性、耐久性、折損性共に○かつ燃料消費量が６２．９以下の場合は◎となっている。   In the judgment column of Table 3, when any of the production possibility, durability, and breakability is x, when the production possibility, durability, and breakability are both ○ and the fuel consumption is more than 63.1 △, production feasibility, durability, breakability are both ◯, and fuel consumption is 63.1 or less and more than 62.9, ◯, production feasibility, durability, breakability is both ◯, and fuel consumption is 62. In the case of 9 or less, it is ◎.

表３のデータから通常のニッケルプラグの燃料消費量を下回るもののデータを使用して重回帰分析を行った。この結果燃料消費量をＹとすると、
Ｙ＝1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋80.342
となる。これが片側貴金属プラグの燃料消費量６２．５ｍｌを下回る寸法を規定すると、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋17.842≦0
となる。更に、両側貴金属プラグの燃料消費量６２．３ｍｌを下回る寸法を規定すると、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋18.042≦0
となる。 A multiple regression analysis was performed using the data of Table 3 below the fuel consumption of a normal nickel plug. As a result, if the fuel consumption is Y,
Y = 1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 +80.342
It becomes. If this stipulates that the fuel consumption of one side precious metal plug is less than 62.5 ml,
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 17.842 ≦ 0
It becomes. Furthermore, if the fuel consumption of the noble metal plugs on both sides is defined to be less than 62.3 ml,
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 18.042≤0
It becomes.

また、前述したねじ径が１４ｍｍ（Ｍ１４）のスパークプラグの場合と同様な理由により、ねじ径が１０ｍｍ（Ｍ１０）のスパークプラグの場合、
1.0≦Ｘ１≦2.5、2.35≦Ｘ２≦3.15、1.0≦Ｘ３≦1.175
の範囲となる。 For the same reason as the spark plug having a screw diameter of 14 mm (M14), the spark plug having a screw diameter of 10 mm (M10),
1.0 ≦ X 1 ≦ 2.5, 2.35 ≦ X 2 ≦ 3.15, 1.0 ≦ X 3 ≦ 1.175
It becomes the range.

ねじ径が１０ｍｍ（Ｍ１０）のスパークプラグでは、接地電極３０の幅Ｘ１（ｍｍ）、接地電極３０の内側部分の長さＸ２（ｍｍ）、接地電極３０の厚みＸ３（ｍｍ）について、上記の条件を満たす範囲内の寸法とすることによって、貴金属チップを使用したスパークプラグと同等以上の低燃費化を行うことができ、低コストでかつ燃料消費量の少ないスパークプラグを提供することができる。 In the spark plug having a screw diameter of 10 mm (M10), the width X 1 (mm) of the ground electrode 30, the length X 2 (mm) of the inner portion of the ground electrode 30, and the thickness X 3 (mm) of the ground electrode 30 are By making the dimensions within the range satisfying the above conditions, it is possible to achieve a fuel consumption equivalent to or higher than that of a spark plug using a noble metal tip, and to provide a spark plug with low cost and low fuel consumption. it can.

以上、本発明を実施形態について説明したが、本発明は、実施形態に限定されるものではなく、各種の変形が可能であることは勿論である。   As mentioned above, although this invention was described about embodiment, this invention is not limited to embodiment, Of course, various deformation | transformation are possible.

例えば、上記した実施形態では、接地電極３０の断面形状が矩形状である場合について説明したが、接地電極３０の断面形状は矩形状以外の形状としてもよい。例えば、図７に示すように、中心電極の方向に向いた中心電極側の面が平面状であり、背面側が円弧状となった形状、換言すれば、丸棒の一方の面（中心電極側の面）を平坦に切削した形状の接地電極３０としてもよい。このように、接地電極３０の断面形状が矩形状でない場合、接地電極３０の幅Ｘ１（ｍｍ）及び厚みＸ３（ｍｍ）とは、それぞれ最大となる部分での幅（図７中に示すＸ１）及び厚み（図７中に示すＸ３）をいう。また、接地電極３０の断面形状は、図８に示すように、中心電極側の面のみでなく背面側の面も平面状としたもの、換言すれば、丸棒の対向面（中心電極側の面と背面側の面）を平坦に切削した形状のものであってもよい。 For example, in the above-described embodiment, the case where the cross-sectional shape of the ground electrode 30 is rectangular has been described, but the cross-sectional shape of the ground electrode 30 may be a shape other than the rectangular shape. For example, as shown in FIG. 7, the surface on the side of the center electrode facing the direction of the center electrode is planar, and the back side is arcuate, in other words, one surface of the round bar (center electrode side Alternatively, the ground electrode 30 may have a shape obtained by cutting the flat surface) flatly. Thus, when the cross-sectional shape of the ground electrode 30 is not rectangular, the width X 1 (mm) and the thickness X 3 (mm) of the ground electrode 30 are the widths at the maximum portions (shown in FIG. 7). X 1 ) and thickness (X 3 shown in FIG. 7). Further, as shown in FIG. 8, the cross-sectional shape of the ground electrode 30 is such that not only the surface on the center electrode side but also the surface on the back surface is planar, in other words, the opposing surface of the round bar (on the center electrode side). It may have a shape obtained by cutting the surface and the surface on the back side flatly.

１００……スパークプラグ、５０……主体金具、１０……絶縁碍子、２０……中心電極、３０……接地電極。   100 ... Spark plug, 50 ... Metal shell, 10 ... Insulator, 20 ... Center electrode, 30 ... Ground electrode.

Claims (6)

外周に取り付け用ねじ部が形成された主体金具と、先端部が前記主体金具から突出するように当該主体金具に保持された絶縁碍子と、先端部が前記絶縁碍子から突出するように当該絶縁碍子に保持された中心電極と、前記主体金具の先端部に配設され、自身の先端部が前記中心電極の先端と対向する接地電極とを具備し、前記取り付け用ねじ部のねじ径が１４ｍｍのスパークプラグにおいて、
前記接地電極のうち前記中心電極の先端に沿った水平面から前記接地電極側の前記中心電極側面に沿った垂直面までの部分における、
幅をＸ１（ｍｍ）、内側面の長さをＸ２（ｍｍ）、厚みをＸ３（ｍｍ）とした時に、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋17.782≦0
但し、1.0≦Ｘ１≦4.2、3.1≦Ｘ２≦4.0、1.0≦Ｘ３≦1.8
であることを特徴とするスパークプラグ。 A metal shell having a mounting screw portion formed on the outer periphery, an insulator held by the metal shell so that the tip protrudes from the metal shell, and the insulator so that the tip protrudes from the insulator A center electrode held on the front end of the metal shell, and a ground electrode disposed on the front end of the metal shell, the front end of the center electrode being opposed to the front end of the center electrode. In the spark plug,
In the portion of the ground electrode from the horizontal plane along the tip of the center electrode to the vertical plane along the side of the center electrode on the ground electrode side,
When the width is X 1 (mm), the length of the inner surface is X 2 (mm), and the thickness is X 3 (mm),
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 17.782 ≦ 0
However, 1.0 ≦ X 1 ≦ 4.2, 3.1 ≦ X 2 ≦ 4.0, 1.0 ≦ X 3 ≦ 1.8
Spark plug characterized by being. 請求項１記載のスパークプラグであって、
0.371Ｘ１ ２＋1.151Ｘ２ ２−1.005Ｘ１−9.019Ｘ２＋0.053Ｘ３＋18.082≦0
但し、1.0≦Ｘ１≦4.2、3.1≦Ｘ２≦4.0、1.0≦Ｘ３≦1.8
であることを特徴とするスパークプラグ。 The spark plug according to claim 1, wherein
0.371X 1 2 + 1.151X 2 2 -1.005X 1 -9.019X 2 + 0.053X 3 + 18.082 ≦ 0
However, 1.0 ≦ X 1 ≦ 4.2, 3.1 ≦ X 2 ≦ 4.0, 1.0 ≦ X 3 ≦ 1.8
Spark plug characterized by being. 外周に取り付け用ねじ部が形成された主体金具と、先端部が前記主体金具から突出するように当該主体金具に保持された絶縁碍子と、先端部が前記絶縁碍子から突出するように当該絶縁碍子に保持された中心電極と、前記主体金具の先端部に配設され、自身の先端部が前記中心電極の先端と対向する接地電極とを具備し、前記取り付け用ねじ部のねじ径が１２ｍｍのスパークプラグにおいて、
前記接地電極のうち前記中心電極の先端に沿った水平面から前記接地電極側の前記中心電極側面に沿った垂直面までの部分における、
幅をＸ１（ｍｍ）、内側面の長さをＸ２（ｍｍ）、厚みをＸ３（ｍｍ）とした時に、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.276≦0
但し、1.0≦Ｘ１≦3.5、2.6≦Ｘ２≦3.5、1.0≦Ｘ３≦1.5
であることを特徴とするスパークプラグ。 A metal shell having a mounting screw portion formed on the outer periphery, an insulator held by the metal shell so that the tip protrudes from the metal shell, and the insulator so that the tip protrudes from the insulator A center electrode held on the front end of the metal shell, and a ground electrode disposed on the front end of the metal shell, the front end of the center electrode being opposed to the front end of the center electrode. In the spark plug,
In the portion of the ground electrode from the horizontal plane along the tip of the center electrode to the vertical plane along the side of the center electrode on the ground electrode side,
When the width is X 1 (mm), the length of the inner surface is X 2 (mm), and the thickness is X 3 (mm),
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.276≤0
However, 1.0 ≦ X 1 ≦ 3.5, 2.6 ≦ X 2 ≦ 3.5, 1.0 ≦ X 3 ≦ 1.5
Spark plug characterized by being. 請求項３記載のスパークプラグであって、
0.623Ｘ１ ２＋0.729Ｘ２ ２−1.658Ｘ１−4.798Ｘ２−0.021Ｘ３＋8.476≦0
但し、1.0≦Ｘ１≦3.5、2.6≦Ｘ２≦3.5、1.0≦Ｘ３≦1.5
であることを特徴とするスパークプラグ。 The spark plug according to claim 3, wherein
0.623X 1 2 + 0.729X 2 2 -1.658X 1 -4.798X 2 -0.021X 3 + 8.476 ≦ 0
However, 1.0 ≦ X 1 ≦ 3.5, 2.6 ≦ X 2 ≦ 3.5, 1.0 ≦ X 3 ≦ 1.5
Spark plug characterized by being. 外周に取り付け用ねじ部が形成された主体金具と、先端部が前記主体金具から突出するように当該主体金具に保持された絶縁碍子と、先端部が前記絶縁碍子から突出するように当該絶縁碍子に保持された中心電極と、前記主体金具の先端部に配設され、自身の先端部が前記中心電極の先端と対向する接地電極とを具備し、前記取り付け用ねじ部のねじ径が１０ｍｍのスパークプラグにおいて、
前記接地電極のうち前記中心電極の先端に沿った水平面から前記接地電極側の前記中心電極側面に沿った垂直面までの部分における、
幅をＸ１（ｍｍ）、内側面の長さをＸ２（ｍｍ）、厚みをＸ３（ｍｍ）とした時に、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋17.842≦0
但し、1.0≦Ｘ１≦2.5、2.35≦Ｘ２≦3.15、1.0≦Ｘ３≦1.175
であることを特徴とするスパークプラグ。 A metal shell having a mounting screw portion formed on the outer periphery, an insulator held by the metal shell so that the tip protrudes from the metal shell, and the insulator so that the tip protrudes from the insulator A center electrode held on the front end of the metal shell, and a grounding electrode disposed at the front end of the metal shell, the front end of the center electrode being opposed to the front end of the center electrode. In the spark plug,
In the portion of the ground electrode from the horizontal plane along the tip of the center electrode to the vertical plane along the side of the center electrode on the ground electrode side,
When the width is X 1 (mm), the length of the inner surface is X 2 (mm), and the thickness is X 3 (mm),
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 17.842 ≦ 0
However, 1.0 ≦ X 1 ≦ 2.5, 2.35 ≦ X 2 ≦ 3.15, 1.0 ≦ X 3 ≦ 1.175
Spark plug characterized by being. 請求項５記載のスパークプラグであって、
1.505Ｘ１ ２＋1.726Ｘ２ ２−3.565Ｘ１−10.436Ｘ２−0.058Ｘ３＋18.042≦0
但し、1.0≦Ｘ１≦2.5、2.35≦Ｘ２≦3.15、1.0≦Ｘ３≦1.175
であることを特徴とするスパークプラグ。 The spark plug according to claim 5, wherein
1.505X 1 2 + 1.726X 2 2 -3.565X 1 -10.436X 2 -0.058X 3 + 18.042≤0
However, 1.0 ≦ X 1 ≦ 2.5, 2.35 ≦ X 2 ≦ 3.15, 1.0 ≦ X 3 ≦ 1.175
Spark plug characterized by being.
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WO2017169930A1 (en) * 2016-03-30 2017-10-05 株式会社デンソー Internal combustion engine spark plug
US9935429B2 (en) 2016-08-31 2018-04-03 Denso Corporation Ignition control system
US10050417B2 (en) 2016-08-31 2018-08-14 Denso Corporation Spark plug and manufacturing method thereof
US10348060B2 (en) 2016-08-30 2019-07-09 Denso Corporation Spark plug

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JPH04154069A (en) * 1990-10-17 1992-05-27 Ngk Spark Plug Co Ltd Spark plug for internal combustion engine
JP2005339864A (en) * 2004-05-25 2005-12-08 Denso Corp Spark plug
JP2007522617A (en) * 2004-02-03 2007-08-09 フェデラル−モーグル・イグニション・ユー・ケー・リミテッド Spark plug configuration with noble metal tip
JP2007234435A (en) * 2006-03-01 2007-09-13 Ngk Spark Plug Co Ltd Spark plug
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JPS5236238A (en) * 1975-09-16 1977-03-19 Shinkosumosu Denki Kk Electric spark plug for automoyive internal combustion engine
JPH04154069A (en) * 1990-10-17 1992-05-27 Ngk Spark Plug Co Ltd Spark plug for internal combustion engine
JP2007522617A (en) * 2004-02-03 2007-08-09 フェデラル−モーグル・イグニション・ユー・ケー・リミテッド Spark plug configuration with noble metal tip
JP2005339864A (en) * 2004-05-25 2005-12-08 Denso Corp Spark plug
JP2007234435A (en) * 2006-03-01 2007-09-13 Ngk Spark Plug Co Ltd Spark plug
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017169930A1 (en) * 2016-03-30 2017-10-05 株式会社デンソー Internal combustion engine spark plug
US20190199068A1 (en) * 2016-03-30 2019-06-27 Denso Corporation Spark plug for internal combustion engine
US10505347B2 (en) 2016-03-30 2019-12-10 Denso Corporation Spark plug for internal combustion engine
US10348060B2 (en) 2016-08-30 2019-07-09 Denso Corporation Spark plug
US9935429B2 (en) 2016-08-31 2018-04-03 Denso Corporation Ignition control system
US10050417B2 (en) 2016-08-31 2018-08-14 Denso Corporation Spark plug and manufacturing method thereof

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