JPH0451484A - Spark plug for internal combustion engine - Google Patents

Spark plug for internal combustion engine

Info

Publication number
JPH0451484A
JPH0451484A JP15867690A JP15867690A JPH0451484A JP H0451484 A JPH0451484 A JP H0451484A JP 15867690 A JP15867690 A JP 15867690A JP 15867690 A JP15867690 A JP 15867690A JP H0451484 A JPH0451484 A JP H0451484A
Authority
JP
Japan
Prior art keywords
tip
center electrode
shaft hole
diameter
groove
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP15867690A
Other languages
Japanese (ja)
Other versions
JP2943002B2 (en
Inventor
Shinichi Nakamura
伸一 中村
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Niterra Co Ltd
Original Assignee
NGK Spark Plug Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NGK Spark Plug Co Ltd filed Critical NGK Spark Plug Co Ltd
Priority to JP15867690A priority Critical patent/JP2943002B2/en
Publication of JPH0451484A publication Critical patent/JPH0451484A/en
Application granted granted Critical
Publication of JP2943002B2 publication Critical patent/JP2943002B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Abstract

PURPOSE:To prevent carbon contamination and degradation generated with combustion and suppress wear of the center electrode by furnishing a groove at the periphery on one side of the tip of the center electrode, which is held by the tip of an insulation member, and introducing a specific relationship between the distance of center electrode from the groove edge at the tip, the diameter at the tip, the diameter of the groove, and the inside dia. of the shaft hole at the tip of the insulation member retaining the center electrode. CONSTITUTION:A thermo-pocket 10 is formed at the periphery near the tip 9 of a center electrode 2, which is retained in the shaft hole 5 of an insulation member 4. Therein, Eq. I given in conjunction with the attached illustration shall be met, where C is the distance of the tip of center electrode 2 from the edge of the thermo-pocket 10, phiD1 is the dia. of the tip 9, phiD2 is the dia. at the thermo-pocket part, and phiH is the inside dia. of the shaft hole 5 of the insulation member 4 retaining the center electrode 2.

Description

【発明の詳細な説明】 (産業上の利用分野) この発明は、内燃機関にH着されるスパークプラグに関
する。
DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a spark plug that is attached to an internal combustion engine.

(従来の技術) 従来、内燃機関の高性能化にともなって、内燃機関に装
着するスパークプラグのメインテナンスフリー化が望j
Sれてきており、そのため燃焼室内で絶縁体の先端部に
カーボンが付着しないように燃焼室内での受熱を中心電
極を介して放散しにくいように中心電極の先端部近傍の
周囲にサーモポケットと呼ばれる凹陥部を周設してなる
ものや、内燃機関の小型化による中心電極の耐久性を確
保するために発火部電極をptチップよりなるものとす
ることが行なわれている。
(Prior Art) Conventionally, as the performance of internal combustion engines has improved, it has become desirable to make spark plugs installed in internal combustion engines maintenance-free.
Therefore, in order to prevent carbon from adhering to the tip of the insulator in the combustion chamber and to make it difficult to dissipate the heat received in the combustion chamber through the center electrode, a thermo pocket is installed around the tip of the center electrode. In order to ensure the durability of the center electrode due to miniaturization of internal combustion engines, the firing part electrode is made of a PT chip.

(発明が解決しようとする課題) しかしながら、上記従来のものにおいて、絶縁体先端部
のカーボンによる汚損を防ぎ、燃焼による受熱を放散し
難くするため、中心電極の先端部近傍の側周にサーモポ
ケットと呼ばれる凹陥部を周設してなるものの場合、加
工にあたっては中心電極を保持する絶縁体の軸孔の内径
とサーモポケットとの距離をS、軸孔内に没するサーモ
ポケットの深さをB、更に軸孔外に露出するサーモポケ
ットの長さをAとした場合、 S≧0.1mm、BaO,5mm。
(Problem to be Solved by the Invention) However, in the above-mentioned conventional device, in order to prevent the tip of the insulator from being contaminated by carbon and to make it difficult to dissipate the heat received by combustion, there is a thermo pocket on the side periphery near the tip of the center electrode. In the case of a device with a circumferential concave part called a , the distance between the inner diameter of the shaft hole of the insulator holding the center electrode and the thermopocket is S, and the depth of the thermopocket sunk into the shaft hole is B. Furthermore, when the length of the thermopocket exposed outside the shaft hole is A, S≧0.1mm, BaO, 5mm.

A≧帆3m、m を満たすものであるが、このようなサーモポケットにお
いては、 S≧0.2mm、B10.8mm の条件において、顕著にその効果が認められるものであ
り、中心電極の先端径φD4、サーモポケットにおける
外径φD2とした時にφD、=φD2とすると、中心電
極自体の径が著しく細径となるため、燃焼乙こ伴う摩耗
が激しくなり、耐久性が低下する恐れがある。
A≧3m, m is satisfied, but in such a thermopocket, the effect is noticeable under the conditions of S≧0.2mm and B10.8mm, and the tip diameter of the center electrode If φD = φD2, where φD4 is the outer diameter of the thermopocket and φD2, then the diameter of the center electrode itself becomes extremely small, so there is a risk that the wear associated with combustion will be severe and the durability will be reduced.

また、中心電極の先端の発火部電極なptチップよりな
るものとする場合、コストの点から細径化ぜざるを得な
くなり、ptチップの周囲にサーモボケッl−を周設す
るとptチップの使用量が著しく多くなってコスI・高
となるものである。
In addition, if the firing part electrode at the tip of the center electrode is made of a PT tip, the diameter must be made smaller due to cost reasons, and if a thermobracket is provided around the PT tip, the amount of PT tip used will be reduced. This results in a significant increase in cost I and high cost.

そこで、この発明は上記従来のものの有する欠点を改善
するものであり、燃焼にともなって発生ずるカーボン汚
損を防止すると共に、中心電極の摩耗を抑制しようとす
るものである。
Therefore, the present invention aims to improve the above-mentioned drawbacks of the prior art, and aims to prevent carbon contamination caused by combustion and suppress wear of the center electrode.

(課題を解決するだめの手段) そのために、絶縁体先端に保持される中心電極の先端部
の−・部にサーモポケットを周設し、−1−記中心電極
の先端の凹溝端縁までの距離なC1その先端直径なφD
1とし、更に凹溝815の直径をφD2、また中心電極
を保持する絶縁体先端の軸孔の内径なφHとした場合、 φD、>φD2、Ca2.5mm、  φD、<φ11
を満たずものとしてなるものである。
(Another means to solve the problem) For this purpose, a thermo pocket is provided around the tip of the center electrode held at the tip of the insulator, and a thermopocket is provided around the edge of the groove at the tip of the center electrode. Distance C1 Its tip diameter φD
1, the diameter of the groove 815 is φD2, and the inner diameter of the shaft hole at the tip of the insulator holding the center electrode is φH, then φD, >φD2, Ca2.5 mm, φD, <φ11
It becomes a thing that satisfies the following.

(作用) 」−記構成を具えるので、1ノーモポケツトを有する中
心電極において、中心電極の先端の凹溝端縁までの距離
、C1その先端直径φD1、凹溝部の直径、φD2、と
中心電極を保持する絶縁体先端の軸孔の内径、φ11が
、4二部条件を満たずものとすることで、この中心電極
を保持する絶縁体の軸孔の内径とサーモポケットとの距
離、S、軸孔内に没するサーモポケットの深さ、B、軸
孔外に露出するサーモポケットの長さAが、 S≧0. 2rnm、  B10.8mm。
(Function) Since the center electrode has the configuration described above, in the center electrode having one normal pocket, the distance from the tip of the center electrode to the edge of the groove, C1, the diameter of the tip, φD1, and the diameter of the groove, φD2, hold the center electrode. By assuming that the inner diameter of the shaft hole at the tip of the insulator, φ11, does not satisfy the 4-part condition, the distance between the inner diameter of the shaft hole of the insulator holding the center electrode and the thermo pocket, S, and the shaft hole The depth of the thermopocket sunk inside, B, and the length A of the thermopocket exposed outside the shaft hole, S≧0. 2rnm, B10.8mm.

A≧0.3mm を満たすものとすることができるので中心電極の先端に
おける受熱な拡散させここくくシ、絶縁体のカーボン汚
損を防止することができる。
Since A≧0.3 mm can be satisfied, heat can be received and diffused at the tip of the center electrode, and carbon contamination of the insulator can be prevented.

(実施例) この発明を図に示す実施例により更に説明する。(Example) This invention will be further explained with reference to embodiments shown in the drawings.

(1)は、この発明の実施例である内燃機関用スパーク
プラグであり、この内燃機関用スパークプラグ(1)は
、先端の軸孔(5)に銅芯(3)を内蔵したニッケル合
金からなる中心電極(2)を配し、軸孔(5)内に抵抗
体(13)を導電性カラス(14)で挟んで端子電極(
15)と共に一体に封着してなる絶縁体(4)と、上記
中心電極(2)の先端に対向する位置に外側電極(7)
を配設し、内燃機関に装着するときに使用するネジ部(
8)を側方に設けてなる主体金具(6)から構成される
ものである。
(1) is a spark plug for an internal combustion engine which is an embodiment of the present invention, and this spark plug (1) for an internal combustion engine is made of a nickel alloy with a built-in copper core (3) in the shaft hole (5) at the tip. A resistor (13) is sandwiched between conductive crows (14) and a terminal electrode (
15) and an insulator (4) integrally sealed with the center electrode (2), and an outer electrode (7) at a position opposite to the tip of the center electrode (2).
The screw part (
8) is provided on the side of the metal shell (6).

そして、上記絶縁体(4)の軸孔(5)内に保持される
中心電極(2)は、先端部(9)の近傍側周にザーモボ
ケッ)(10)を周設してなるものであり、このように
中心電極(2)の先端部(9)の一部側周にサーモボケ
ッ)(10)を周設するものにおいて、」−記中心電極
(2)の先端のザーモボケッ)(10)の端縁までの距
離なC1その先端部(9)の直径をφD、とし、更にサ
ーモポケットにおける直径なφD2、また中心電極(2
)を保持する絶縁体(4)の軸孔(5)の内径をφHと
した場合、 φD 、 >φD2、Ca2. 5mrn、 φD、<
φHを満たしてなるものである。
The center electrode (2) held in the shaft hole (5) of the insulator (4) has a thermobracket (10) provided around the side near the tip (9). In this way, in the case where the thermo-bokeh (10) is provided around a part of the side circumference of the tip (9) of the center electrode (2), the thermo-boke (10) at the tip of the center electrode (2) is The distance to the edge is C1, and the diameter of its tip (9) is φD, and the diameter at the thermopocket is φD2, and the center electrode (2
), when the inner diameter of the shaft hole (5) of the insulator (4) holding the insulator (4) is φH, φD , >φD2, Ca2. 5mrn, φD, <
It satisfies φH.

この発明が以上の構成を具えるものであるので、サーモ
ポケット(10)を有する中心電極(2)において、中
心電極(2)を保持する絶縁体(4)の軸孔(5)の内
径とサーモボケッ)(10)の底部との距離なS、軸孔
(5)内に没するサーモポケットの深さをB、更に軸孔
(5)外に露出するサーモポケットの長さをAとした場
合、S≧0.2mm、B10.8mm。
Since the present invention has the above configuration, in the center electrode (2) having the thermopocket (10), the inner diameter of the shaft hole (5) of the insulator (4) holding the center electrode (2) and When S is the distance from the bottom of the thermo pocket (10), B is the depth of the thermo pocket sunk into the shaft hole (5), and A is the length of the thermo pocket exposed outside the shaft hole (5). , S≧0.2mm, B10.8mm.

A≧0.3mm を溝たずものとすることができ、更にφD、>φD2と
することで、電極面積が増えるので耐久性が向−1−シ
、Ca2.5mmとすることで通常の電極消耗M0.4
mmに対応することができ、更に、内燃機関の燃焼室内
において燃焼に伴って発生するカーボンが絶縁体(4)
の先端に付着しても、中心電極(2)の先端部(9)に
おける燃焼に31−って受けた熱が放散し難くなるので
、カーボンを確実に除去することができるものである。
A≧0.3mm can be made into a grooved pattern, and by setting φD and >φD2, the electrode area increases, so the durability improves. Consumption M0.4
In addition, carbon generated during combustion in the combustion chamber of an internal combustion engine can be used as an insulator (4).
Even if carbon adheres to the tip of the center electrode (2), the heat received by combustion at the tip (9) of the center electrode (2) becomes difficult to dissipate, so that carbon can be reliably removed.

また、第33図に示すよう仁こ中心電極(2)のサーモ
ボケッ1−(10)の一端を段部(12)とすることに
よって、中心電極(2)の先端部(9)の受けた熱を、
先端部(9)により保持しやすくなるので、カーボン汚
損に十分に対応することができる。
In addition, as shown in FIG. 33, by forming one end of the thermo-bokeh 1-(10) of the center electrode (2) into a step (12), the heat received by the tip (9) of the center electrode (2) can be increased. of,
Since the tip portion (9) makes it easier to hold, it is possible to sufficiently deal with carbon contamination.

更に、第4図に示すように、中心電極(2)の先端部(
9)頂部に7字溝(11)を穿設することによって、火
炎核の成長を拡大し燃料への着火性を向上ざぜることが
てきるから、不完全な燃焼によって生しるカーボンの発
生を抑制することができると共に、中心電極(2)のサ
ーモポケット(10)によってカーボン汚損を防止でき
るので、スパークプラク(1)自体の耐久性を十分に確
保し、メインテナンスをより容易なものとすることがで
きる。
Furthermore, as shown in FIG. 4, the tip of the center electrode (2) (
9) By drilling the figure 7 groove (11) at the top, it is possible to expand the growth of the flame kernel and improve the ignition of the fuel, thereby reducing the generation of carbon caused by incomplete combustion. In addition, carbon contamination can be prevented by the thermo pocket (10) of the center electrode (2), ensuring sufficient durability of the spark plaque (1) itself and making maintenance easier. be able to.

(発明の効果) 以」二のとおり、中心電極の先端部近傍にサーモポケッ
トを設けると共に、中心電極先端部等を一定に加工する
ことて、燃焼によって受ける熱により、燃焼にともなっ
て発生ずるカーホンの絶縁体先端部の汚損を防止するこ
とができるので、メインテナンスを容易にすることがで
きると共に、スパークプラグの耐久性を向」二ざぜるこ
とができる優れた効果を有するものである。
(Effects of the Invention) As described in Section 2 below, by providing a thermopocket near the tip of the center electrode and by processing the tip of the center electrode in a certain manner, the heat received during combustion can reduce the carphone generated during combustion. Since the tip of the insulator can be prevented from becoming dirty, maintenance can be facilitated and the durability of the spark plug can be improved.

【図面の簡単な説明】[Brief explanation of drawings]

第1図はこの発明の実施例である内燃機関用スパークプ
ラクの部分断面図、第2図はその要部拡大断面図、第3
図及び第4図はその他の実施例の要部拡大断面図である
。 1・・・内燃機関用スパークプラク 2・・・中心電極
3・・・銅芯 4・・・絶縁体 5・・・軸孔6・・・
主体金具 7・・・外側電極 8・・・ネジ部9・・・
先端部 10・・・サーモポケット11・・・7字溝 
】2・・・段部 13・・・抵抗体14・・・導電性カ
ラス 】5・・・端子電極特許出願人 日本特殊陶業株
式会社 代理人 弁理士 藤 木 三 幸
FIG. 1 is a partial cross-sectional view of a spark plaque for an internal combustion engine which is an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the main part thereof, and FIG.
This figure and FIG. 4 are enlarged sectional views of main parts of other embodiments. 1... Spark plaque for internal combustion engine 2... Center electrode 3... Copper core 4... Insulator 5... Shaft hole 6...
Metal shell 7...Outer electrode 8...Threaded part 9...
Tip part 10...Thermo pocket 11...7-shaped groove
]2... Stepped portion 13... Resistor 14... Conductive glass ]5... Terminal electrode patent applicant NGK Spark Plug Co., Ltd. Agent Patent attorney Miyuki Fujiki

Claims (1)

【特許請求の範囲】 絶縁体先端に保持される中心電極の先端部の一部側周に
凹溝部を周設するものにおいて、上記中心電極の先端の
凹溝端縁までの距離をC、その先端直径をφD_1とし
、更に凹溝部の直径をφD_2、また中心電極を保持す
る絶縁体先端の軸孔の内径をφHとした場合、 φD_1>φD_2、C≧0.5mm、φD_1<φH
を満たしてなる内燃機関用スパークプラグ。
[Claims] In a device in which a groove is provided around a part of the side circumference of the tip of a center electrode held at the tip of an insulator, the distance from the tip of the center electrode to the edge of the groove is C, and the tip If the diameter is φD_1, the diameter of the groove is φD_2, and the inner diameter of the shaft hole at the tip of the insulator that holds the center electrode is φH, then φD_1>φD_2, C≧0.5mm, φD_1<φH
Spark plugs for internal combustion engines that meet the following requirements.
JP15867690A 1990-06-19 1990-06-19 Spark plug for internal combustion engine Expired - Fee Related JP2943002B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15867690A JP2943002B2 (en) 1990-06-19 1990-06-19 Spark plug for internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15867690A JP2943002B2 (en) 1990-06-19 1990-06-19 Spark plug for internal combustion engine

Publications (2)

Publication Number Publication Date
JPH0451484A true JPH0451484A (en) 1992-02-19
JP2943002B2 JP2943002B2 (en) 1999-08-30

Family

ID=15676934

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15867690A Expired - Fee Related JP2943002B2 (en) 1990-06-19 1990-06-19 Spark plug for internal combustion engine

Country Status (1)

Country Link
JP (1) JP2943002B2 (en)

Also Published As

Publication number Publication date
JP2943002B2 (en) 1999-08-30

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