JPH02204988A - Spark plug of internal combustion engine - Google Patents
Spark plug of internal combustion engineInfo
- Publication number
- JPH02204988A JPH02204988A JP2468289A JP2468289A JPH02204988A JP H02204988 A JPH02204988 A JP H02204988A JP 2468289 A JP2468289 A JP 2468289A JP 2468289 A JP2468289 A JP 2468289A JP H02204988 A JPH02204988 A JP H02204988A
- Authority
- JP
- Japan
- Prior art keywords
- tip
- diameter
- insulator
- spark plug
- center electrode
- 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.)
- Pending
Links
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 10
- 229910052751 metal Inorganic materials 0.000 claims abstract description 19
- 239000002184 metal Substances 0.000 claims abstract description 19
- 239000012212 insulator Substances 0.000 claims description 41
- 238000009413 insulation Methods 0.000 abstract description 6
- 230000035939 shock Effects 0.000 abstract description 6
- 229910000990 Ni alloy Inorganic materials 0.000 abstract description 2
- 238000005336 cracking Methods 0.000 description 4
- 238000005452 bending Methods 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Ignition Installations For Internal Combustion Engines (AREA)
- Spark Plugs (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、内燃機関のスパークプラグに係わり、特に、
熱衝撃が大きいロータリーエンジン用やレース用エンジ
ンに好適なスパークプラグに関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spark plug for an internal combustion engine, and in particular,
This invention relates to a spark plug suitable for rotary engines and racing engines that experience large thermal shocks.
［従来の技術］
内燃機関のスパークプラグは、通常、筒状主体金具と、
この主体金具に嵌め込まれる軸孔付きの絶縁体と、先端
部を前記絶縁体の先端から突出して軸孔に嵌め込まれる
中心電極とからなり、前記中心電極の先端と前記主体金
具の先端部との間に火花放電間隙を形成している。[Prior Art] A spark plug for an internal combustion engine usually includes a cylindrical metal shell,
It consists of an insulator with a shaft hole fitted into the metal shell, and a center electrode whose tip protrudes from the tip of the insulator and is fitted into the shaft hole, and the tip of the center electrode and the tip of the metal shell are connected. A spark discharge gap is formed between them.
［発明が解決しようとする課題］
しかるに、従来のスパークプラグはつぎのような欠点が
ある。[Problems to be Solved by the Invention] However, conventional spark plugs have the following drawbacks.
吸入混合気により冷却される時間が短いロータリーエン
ジンや、急冷、急熱を伴うレース用エンジンにこのよう
なスパークプラグを使用すると、絶縁体は熱衝撃を受は
割れを生じることがある。If such a spark plug is used in a rotary engine, which requires a short cooling time with the intake air-fuel mixture, or a racing engine, which requires rapid cooling and heating, the insulator may receive thermal shock and crack.
本発明の目的は、熱衝撃が大きいエンジンに装着しても
絶縁体割れを生じ難い内燃機関のスパークプラグの提供
にある。SUMMARY OF THE INVENTION An object of the present invention is to provide a spark plug for an internal combustion engine that is unlikely to cause cracking of the insulator even when installed in an engine subject to large thermal shocks.
［課題を解決するための手段］
上記目的を達成するため、本発明はつぎの構成を採用し
た。[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following configuration.
内燃機関のスパークプラグは、筒状主体金具と、該主体
金具に嵌め込まれる軸孔付きの絶縁体と、先端部を前記
絶縁体の先端から突出して軸孔に嵌め込まれ先端が径大
鍔状部となる中心電極とからなり、Ａを絶縁体の先端の
直径、Ｂを前記径大鍔状部の先端面の直径、Ｃを絶縁体
の脚長部の寸法Ｆの先端側１／３位置における絶縁体の
外径、Ｊを軸孔内の中心電極の直径、Ｅを絶縁体先端か
ら径大鍔状部までの距離とした場合、径大鍔状部の先端
面の直径Ｂは、Ａ＜Ｂ≦ＣＸ１．２およびＢ≦ＪＸ３．
０を満たし、かつ、絶縁体先端から径大鍔状部までの距
ＩＩＭＥは、Ｏ（ｍｍ）≦Ｅ≦５（ｍｍ）を満たす。A spark plug for an internal combustion engine includes a cylindrical metal shell, an insulator with a shaft hole that is fitted into the metal shell, and a large-diameter flanged portion whose tip protrudes from the tip of the insulator and is fitted into the shaft hole. A is the diameter of the tip of the insulator, B is the diameter of the tip surface of the large-diameter brim, and C is the insulation at the tip side 1/3 of the dimension F of the long leg of the insulator. When J is the outer diameter of the body, J is the diameter of the center electrode in the shaft hole, and E is the distance from the tip of the insulator to the large diameter flange, the diameter B of the tip surface of the large diameter flange is A<B. ≦CX1.2 and B≦JX3.
0, and the distance IIME from the tip of the insulator to the large-diameter brim portion satisfies O (mm)≦E≦5 (mm).
［作用および発明の効果］
本発明の内燃機関のスパークプラグは、次の作用および
効果を生じる。[Actions and Effects of the Invention] The spark plug for an internal combustion engine of the present invention produces the following actions and effects.
中心電極の先端は径大鍔状部となっている。このため、
熱衝撃を受けても径大鍔状部の中心電極に熱が捕捉され
速やかに熱引きが行われ、絶縁体の急激な温度上昇や異
常過熱が防止できる。よって、絶縁体の割れは生じ難い
。The tip of the center electrode is a large-diameter brim-shaped portion. For this reason,
Even if it receives a thermal shock, the heat is captured by the center electrode of the large-diameter brim and is quickly removed, thereby preventing a sudden temperature rise or abnormal overheating of the insulator. Therefore, cracks in the insulator are less likely to occur.
数値限定はつぎのとおりである。The numerical limitations are as follows.
Ｂ≦Ａであると絶縁体は熱衝撃をまともに受は割れを生
じ易くなる。Ｂ＞ＣＸ１．２であると着火性に劣るよう
になる。If B≦A, the insulator will not be able to properly absorb thermal shock and will be prone to cracking. If B>CX1.2, the ignitability will be poor.
Ｂ＞ＪＸ３．Ｏであると長すぎ、折損、曲り、焼は等の
中心電極の不具合が増大する。B>JX3. If it is O, it will be too long and problems with the center electrode such as breakage, bending, and burnout will increase.
Ｅ＞５ （ｍｍ）であると長すぎ、中心電極が著しく高
温となり、火花消耗が過大となったり、曲り等が生じ易
くなる。If E>5 (mm), the length is too long and the center electrode becomes extremely hot, resulting in excessive spark consumption and bending.
［実施例］
本発明の第１実施例を第１図、第２図および第３図に基
づき説明する。[Example] A first example of the present invention will be described based on FIGS. 1, 2, and 3.
第１図に示すごとく、スパークプラグ１００は、筒状主
体金具１と、この主体金具１に嵌め込まれる軸孔２１付
きの絶縁体２と、径大鍔状部３１を前記絶縁体２の先端
２３から突出して軸孔２１に嵌め込まれる中心電極３と
からなる。また、前記径大鍔状部３１と主体金具１の環
状の先端部１１との間に火花放電間隙３２が形成されて
いる。As shown in FIG. 1, the spark plug 100 includes a cylindrical metal shell 1, an insulator 2 with a shaft hole 21 that is fitted into the metal shell 1, and a large-diameter brim portion 31 connected to a tip 23 of the insulator 2. It consists of a center electrode 3 that protrudes from the shaft hole 21 and is fitted into the shaft hole 21. Further, a spark discharge gap 32 is formed between the large-diameter flange-shaped portion 31 and the annular tip portion 11 of the metal shell 1.
筒状主体金具１は、炭素鋼で形成され、内壁のテーパ面
１２にパツキン１３を介して前記絶縁体２の脚長部基底
２２を固定している。また、外周にはねじ１４が螺刻さ
れている。The cylindrical metal shell 1 is made of carbon steel, and has a leg base 22 of the insulator 2 fixed to a tapered surface 12 of an inner wall via a packing 13. Further, a screw 14 is threaded on the outer periphery.
絶縁体２は、アルミナ等のセラミックで形成され、先端
２３が前記主体金具１の先端面１５よりやや内方となる
ように配設されている。ここで、Ａは絶縁体２の先端２
３の直径、Ｆは脚長部の寸法、ＤはＦ／３の寸法、Ｃは
ＤＩ（寸法りの後端）位置での絶縁体２の外径である。The insulator 2 is made of ceramic such as alumina, and is disposed such that the tip 23 is slightly inward from the tip surface 15 of the metal shell 1. Here, A is the tip 2 of the insulator 2
3, F is the dimension of the leg length, D is the dimension of F/3, and C is the outer diameter of the insulator 2 at the DI (rear end of the dimension) position.
なお、本実施例において上記寸法は、Ａ＝４．８ｍｍ、
Ｃ＝６ｍｍである。In addition, in this example, the above dimensions are A=4.8 mm,
C=6mm.
中心電極３は全体の形状が断面路丁字状を呈し、ニッケ
ル合金で形成されている。ここで、Ｂは径大鍔状部３１
の先端面の直、径、Ｅは絶縁体２の先端２３から径大鍔
状部３１までの距離、Ｋは径大鍔状部３１の側壁具、Ｊ
は軸孔２１内の中心電極３の直径である。なお、本実施
例において上記各寸法は、Ｅ＝５ｍｍ、に＝１ｍｍ、Ｂ
＝４．９ｍｍ、Ｊ＝２ｍｍである。The center electrode 3 has a T-shaped cross section as a whole and is made of a nickel alloy. Here, B is the large diameter flanged portion 31
, E is the distance from the tip 23 of the insulator 2 to the large-diameter flanged portion 31, K is the side wall fitting of the large-diameter flanged portion 31, and J
is the diameter of the center electrode 3 within the shaft hole 21. In addition, in this example, the above dimensions are E=5 mm, B=1 mm, and B.
=4.9mm, J=2mm.
つぎに、スパークプラグ１００における各部の寸法の最
適範囲を第２図、第３図とともに説明する。Next, the optimum range of dimensions of each part of the spark plug 100 will be explained with reference to FIGS. 2 and 3.
第２図は、横軸を径大鍔状部３１の先端面の直径Ｂ、縦
軸を絶縁体２の割れ発生頻度とし、４サイクル、２００
０ｃｃエンジンにスパークプラグ１００を装着してアイ
ドリング１分と５０００ｒｐｍＸ４／４（負荷全開）１
分の冷熱サイクル試験を行った結果である。このグラフ
より絶縁体２の割れ発生頻度は直径ＢがＡを越えるよう
にすれば急激に低減できることが分かる。ただし、直径
Ｂが外径Ｃの１．２倍を越えると着火性が悪くなる。よ
って、直径Ｂの最適値はつぎのようになる。In FIG. 2, the horizontal axis is the diameter B of the tip surface of the large-diameter flanged portion 31, and the vertical axis is the frequency of cracking in the insulator 2.
Install spark plug 100 on 0cc engine, idling for 1 minute and 5000 rpm x 4/4 (full load) 1
These are the results of a thermal cycle test conducted for several minutes. It can be seen from this graph that the frequency of cracking in the insulator 2 can be sharply reduced by making the diameter B exceed A. However, if the diameter B exceeds 1.2 times the outer diameter C, ignitability will deteriorate. Therefore, the optimum value of diameter B is as follows.
Ａ＜Ｂ≦ＣＸ１．２ ・・・・・・・・・・・・・・
・■（但し、Ｄ＝Ｆ／３ ；Ｃ！、ｔＤ１位置での絶縁
体２の外径）
第３図は、横軸を径大鍔状部３１の先端面の直径Ｂとし
、直径Ｂを増減さぜた場合の中心電極３の不具合（折損
、曲り、焼け）頻度を縦軸としている。このグラフより
直径Ｂの最適値はつぎのようになる。A<B≦CX1.2 ・・・・・・・・・・・・・・・
・■ (However, D=F/3; C!, the outer diameter of the insulator 2 at the tD1 position) In FIG. The vertical axis represents the frequency of defects (breakage, bending, burning) of the center electrode 3 when the number is increased or decreased. From this graph, the optimum value for the diameter B is as follows.
Ｂ≦ＪＸ３．Ｏ・・・・・・・・・・・・・・・・・・
・・・・・・■また、絶縁体２の先端２３から径大鍔状
部３１までの距離Ｅが５ｍｍを越えると中心電極２の温
度」−昇が急増する。よって距離Ｅのとる範囲はつぎの
とおりである。B≦JX3. O・・・・・・・・・・・・・・・・・・
. . . ■Furthermore, when the distance E from the tip 23 of the insulator 2 to the large-diameter flanged portion 31 exceeds 5 mm, the temperature of the center electrode 2 increases rapidly. Therefore, the range of distance E is as follows.
０ （ｍｍ）≦Ｅ≦５ （ｍｍ） −・−・■よって
、径大鍔状部３１の先端面の直径Ｂ、および絶縁体２の
先端２３から径大鍔状部３１までの距離Ｅは、上記■■
■の全ての条件を同時に満たす必要がある。なお、好ま
しくは着火性の面からＥ＝Ｏｍｍよりも０．５ｍｍ以上
離したほうが良い。0 (mm)≦E≦5 (mm) −・−・■ Therefore, the diameter B of the tip surface of the large diameter flanged portion 31 and the distance E from the tip 23 of the insulator 2 to the large diameter flanged portion 31 are as follows. , above ■■
It is necessary to simultaneously satisfy all of the conditions in ■. In addition, from the viewpoint of ignitability, it is preferable that the distance be 0.5 mm or more from E=Omm.
つぎに、本発明の第２実施例を第４図とともに説明する
。Next, a second embodiment of the present invention will be described with reference to FIG.
スパークプラグ２００は径大鍔状部３１の断面形状が台
形であり、径大鍔状部３１の先端面を先端面１５より０
．２ｍｍ内方に配設している。なお、本実施例において
各寸法は、Ｅ＝１ｍｍ、に＝１ｍｍ、Ａ＝４ｍｍ、Ｉｌ
＝５ｍｍ、Ｃ＝６ｍｍ。In the spark plug 200, the cross-sectional shape of the large-diameter flanged portion 31 is trapezoidal, and the distal end surface of the large-diameter flanged portion 31 is 0.00 mm from the distal end surface 15.
．． It is placed 2mm inward. In addition, in this example, each dimension is E=1 mm, 2=1 mm, A=4 mm, Il
=5mm, C=6mm.
Ｊ＝２ｍｍである。スパークプラグ２００は径大鍔状部
３１の断面形状を台形にしているので耐くすぶり汚損に
有利である。J=2mm. Since the spark plug 200 has a trapezoidal cross-sectional shape of the large-diameter flanged portion 31, it is advantageous in terms of resistance to smoldering and contamination.
つぎに、本発明の第３実施例を第５図とともに説明する
。Next, a third embodiment of the present invention will be described with reference to FIG.
スパークプラグ３００は径大鍔状部３１の断面形状が台
形であり、径大鍔状部３１の先端面を先端面１５より０
．５ｍｍ外方に配設している。なお、本実施例において
各寸法は、Ｅ＝＝１ｍｍ、に＝１ｍｍ、Ａ＝４ｍｍ、Ｂ
＝５ｍｍＳＣ＝６ｍｍ、Ｊ＝２ｍｍである。スパークプ
ラグ３００は径大鍔状部３１の断面形状が台形にしてい
るので耐くすぶり汚損に有利であり、径大鍔状部３１の
先端面を先端面１５より外方に配設しているので着火が
有利となる。The spark plug 300 has a large-diameter flanged portion 31 having a trapezoidal cross-sectional shape, and the distal end surface of the large-diameter flanged portion 31 is 0.00 mm from the distal end surface 15.
．． It is placed 5mm outward. In addition, in this example, each dimension is E==1 mm, A=1 mm, A=4 mm, and B.
=5mmSC=6mm, J=2mm. The spark plug 300 has a trapezoidal cross-sectional shape of the large-diameter flanged portion 31, which is advantageous in preventing smoldering and contamination, and the distal end surface of the large-diameter flanged portion 31 is disposed outward from the distal end surface 15. Ignition is advantageous.
つぎに、本発明の第４実施例を第６図とともに説明する
。Next, a fourth embodiment of the present invention will be described with reference to FIG.
スパークプラグ４００は径大鍔状部３１の先端面を先端
面１５より０．２ｍｍ内方に配設している。なお、本実
施例において各寸法は、Ｅ−Ｏｍｍ＋に＝１ｍｍ＋Ａ＝
４ｍｍ＋Ｂ＝５ｍｍ＋Ｃ＝６ｍｍ、Ｊ＝２ｍｍである。In the spark plug 400, the tip surface of the large-diameter flanged portion 31 is disposed 0.2 mm inward from the tip surface 15. In addition, in this example, each dimension is E-Omm+=1mm+A=
4mm+B=5mm+C=6mm, J=2mm.
スパークプラグ４００はＥ＝Ｏｍｍとし、径大鍔状部３
１により絶縁体２の先端２３を間隔をあけずに覆うので
熱引きに有利である。The spark plug 400 has E=Omm, and the large diameter flange 3
1 covers the tip 23 of the insulator 2 without leaving any space between them, which is advantageous in removing heat.
つぎに、本発明の第５実施例を第７図とともに説明する
。Next, a fifth embodiment of the present invention will be described with reference to FIG.
スパークプラグ５００は主体金具１の先端部１１を内方
に曲げ径大鍔状部３１の側壁具にとの対応を図っている
。また、スパークプラグ５００は径大鍔状部３１の断山
形状が台形であり、径大鍔状部３１の先端面を先端部１
５より０．２ｍｍ内方に配設している。なお、本実施例
において各寸法は、Ｅ＝１ｍｍ、に＝１ｍｍ、Ａ＝４ｍ
ｍ、Ｂ＝５ｍｍ、Ｃ＝６ｍｍ、Ｊ＝２ｍｍである。スパ
ークプラグ５００は先端部１１を内方に曲げているので
着火に有利となる。In the spark plug 500, the tip end 11 of the metal shell 1 is bent inward to fit into the side wall fitting of the large-diameter flange-like portion 31. Further, in the spark plug 500, the large diameter flange 31 has a trapezoidal shape, and the tip surface of the large diameter flange 31 is connected to the tip 1.
It is arranged 0.2 mm inward from 5. In addition, in this example, each dimension is E = 1 mm, 2 = 1 mm, and A = 4 m.
m, B=5 mm, C=6 mm, and J=2 mm. Since the spark plug 500 has its tip 11 bent inward, it is advantageous for ignition.
つぎに、本発明の第６実施例を第８図とともに説明する
。Next, a sixth embodiment of the present invention will be described with reference to FIG.
スパークプラグ６００は主体金具１の先端部１１を内方
に曲げるとともに角１６をテーパ状にしている。また、
スパークプラグ６００は径大鍔状部３１の断面形状が台
形であり、径大鍔状部３１の先端面を先端面１５より１
ｍｍ外方に配設している。火花放電間隙３２（距Ｗ１．
１ｍｍ）は角１６とテーパ面３３との間に形成される。In the spark plug 600, the tip 11 of the metal shell 1 is bent inward, and the corners 16 are tapered. Also,
In the spark plug 600, the large-diameter flanged portion 31 has a trapezoidal cross-sectional shape, and the distal end surface of the large-diameter flanged portion 31 is one point smaller than the distal end surface 15.
It is located mm outward. Spark discharge gap 32 (distance W1.
1 mm) is formed between the corner 16 and the tapered surface 33.
なお、本実施例において各寸法は、Ｅ＝２ｍｍ、に＝０
゜５ｍｍＳＢ＝４ｍｍＳＡ＝３．９ｍｍ、Ｃ＝６ｍｍ、
Ｊ＝２ｍｍである。スパークプラグ６００は着火性が第
５実施例のものより良くなる。In addition, in this example, each dimension is E=2 mm, and E=0.
゜5mmSB=4mmSA=3.9mm, C=6mm,
J=2mm. The spark plug 600 has better ignitability than that of the fifth embodiment.
つぎに、本発明の第７実施例を第９図とともに説明する
。Next, a seventh embodiment of the present invention will be described with reference to FIG.
スパークプラグ７００は主体金具１の先端部１１を内方
に曲げるとともに角１６をテーパ状にしている。径大鍔
状部３１に至る部分３４を断面路Ｊ字状に湾曲させてい
る。火花放電間隙３２（距１ｉｉｆｔ１．１ｍｍ）は角
１６と部分３４との間に形成される。なお、本実施例に
おいて各寸法は、Ｅ＝３ｍｍ、に＝１ｍｍ、Ａ＝５ｍｍ
、Ｂ＝５．２ｍｍ、Ｃ＝６ｍｍ、、Ｌ＝２ｍｍである。In the spark plug 700, the tip end 11 of the metal shell 1 is bent inward and the corner 16 is tapered. A portion 34 reaching the large-diameter brim portion 31 is curved to have a J-shaped cross section. A spark discharge gap 32 (distance 1iift 1.1 mm) is formed between the corner 16 and the portion 34. In addition, in this example, each dimension is E = 3 mm, 2 = 1 mm, and A = 5 mm.
, B=5.2 mm, C=6 mm, and L=2 mm.
スパークプラグ７００は第６実施例のものより更に着火
性が向上、する。The spark plug 700 has further improved ignition performance than that of the sixth embodiment.
つぎに、本発明の第８実施例を第１０図とともに説明す
る。Next, an eighth embodiment of the present invention will be described with reference to FIG.
スパークプラグ８００は径大鍔状部３１の先端面を先端
面１５より０．５ｍｍ内方に配設している。なお、本実
施例において各寸法は、Ｅ＝Ｏｍｍ−Ｋ＝１ｍｍ、Ａ＝
４．９ｍｍ＋Ｂ＝５ｍｍ。In the spark plug 800, the distal end surface of the large-diameter flanged portion 31 is disposed 0.5 mm inward from the distal end surface 15. In addition, in this example, each dimension is E=Omm-K=1mm, A=
4.9mm+B=5mm.
Ｃ＝６ｍｍ、Ｊ＝２ｍｍである。スパークプラグ８００
はＥ＝Ｏｍｍとし、径大鍔状部３１により絶縁体２の先
端２３を間隔をあけずに覆うので熱引きに有利であり、
径大鍔状部３１の引っ込み度合いが大きいので中心電極
３が著しく高温とならない。C=6 mm, J=2 mm. spark plug 800
is E=Omm, and since the large-diameter flanged portion 31 covers the tip 23 of the insulator 2 without leaving any space, it is advantageous for heat dissipation.
Since the degree of retraction of the large-diameter brim portion 31 is large, the center electrode 3 does not become extremely hot.
本発明は上記実施例以外に次の実施態様を含む。The present invention includes the following embodiments in addition to the above embodiments.
ａ、径大鍔状部３１の形状は、外周部がロレット目が刻
まれていても良く、径大鍔状部３１の先端面の直径Ｂは
この場合、最外周の長さである。a. The shape of the large-diameter flanged portion 31 may be such that the outer circumference is knurled, and the diameter B of the tip surface of the large-diameter flanged portion 31 is the length of the outermost circumference in this case.
ｂ、中心電極３は熱引きが良い材料が好適であり、多層
構造であっても良い。b. The center electrode 3 is preferably made of a material with good heat conductivity, and may have a multilayer structure.
Ｃ１絶縁体２はアルミナ以外に、窒化アルミ、窒化珪素
、窒化硼素など窒化物系のセラミック焼結体であっても
良い。In addition to alumina, the C1 insulator 2 may be a nitride-based ceramic sintered body such as aluminum nitride, silicon nitride, or boron nitride.
第１図は本発明にかかるスパークプラグの第１実施例を
示す部分断面図である。
第２図はそのスパークプラグの冷熱サイクル試験結果を
示すグラフ、第３図はそのプラグの径大鍔状部３１の先
端面の直径と中心電極の不具合頻度との関係を示すグラ
フである。
第４図は本発明にかかるスパークプラグの第２実施例を
示す要部断面図、第５図はその第３実施例を示す要部断
面図、第６図はその第４実施例を示す要部断面図、第７
図はその第５実施例を示す要部断面図、第８図はその第
６実施例を示す要部断面図、第９図はその第７実施例を
示す要部断面図、第１０図はその第８実施例を示す要部
断面図である。
図中 １・・・筒状主体金具 ２・・・絶縁体 ３・・
・中心電極 １１・・・先端部 １５・・・先端面 ２
１川軸孔 ２３・・・先端 ３１・・・径大鍔状部 ３
２・・・火花放電間隙 １００．２００．３００．４０
０，５００．６００．７００．８００・・・スパークプ
ラグ（内燃機関のスパークプラグ） Ａ・・・絶縁体の
先端の直径 Ｂ・・・径大鍔状部の先端面の直径 Ｃ・
・・Ｄ１位置での絶縁体の外径である（絶縁体の脚長部
の先端側１／３位置における絶縁体の外径）Ｊ・・・軸
孔内の中心電極の直径 Ｅ・・・絶縁体先端から径大鍔
状部までの距離 Ｆ・・・絶縁体の脚長部の寸法
第４図
第７図
第８図
第５図
第６図
手続補正書
３゜
４゜
発明の名称
内燃機関のスパークプラグ
補正をする者
事件との関係 特許出願人
住 所 名古屋市瑞穂区高辻町１４番１８号氏 名
（４５４）日本特殊陶業株式会社代表者 鈴 木 亭
代理人〒４６５電話０５２−７０４−１５５１住 所
名古屋市名東区−社三丁目９６番地補正の対象
図面
四玄社届４諏佃奪歓FIG. 1 is a partial sectional view showing a first embodiment of a spark plug according to the present invention. FIG. 2 is a graph showing the results of a thermal cycle test of the spark plug, and FIG. 3 is a graph showing the relationship between the diameter of the tip surface of the large-diameter brim portion 31 of the plug and the frequency of failures of the center electrode. FIG. 4 is a sectional view of essential parts showing a second embodiment of the spark plug according to the present invention, FIG. 5 is a sectional view of essential parts showing a third embodiment thereof, and FIG. 6 is a sectional view of essential parts showing a fourth embodiment thereof. Partial sectional view, No. 7
The figure is a cross-sectional view of the main part showing the fifth embodiment, FIG. 8 is a cross-sectional view of the main part showing the sixth embodiment, FIG. 9 is a cross-sectional view of the main part showing the seventh embodiment, and FIG. It is a principal part sectional view showing the 8th example. In the diagram: 1... Cylindrical metal shell 2... Insulator 3...
・Center electrode 11...Tip part 15...Tip surface 2
1 River axis hole 23...Tip 31...Large diameter flanged part 3
2...Spark discharge gap 100.200.300.40
0,500.600.700.800...Spark plug (spark plug for internal combustion engine) A...Diameter of the tip of the insulator B...Diameter of the tip surface of the large diameter brim C.
...Outer diameter of the insulator at the D1 position (outer diameter of the insulator at the tip 1/3 position of the long leg portion of the insulator) J...Diameter of the center electrode in the shaft hole E...Insulation Distance from the tip of the body to the large-diameter flanged part F...Dimensions of the leg length of the insulator Figure 4 Figure 7 Figure 8 Figure 5 Figure 6 Procedural amendment 3゜4゜Name of the invention Relationship with the Spark Plug Correction Case Patent Applicant Address 14-18 Takatsuji-cho, Mizuho-ku, Nagoya Name
(454) NGK Spark Plug Co., Ltd. Representative Tei Suzuki Agent 465 Telephone 052-704-1551 Address
Nagoya City Meito Ward - Sha 3-chome 96 Target of correction
Drawing of Shigensha Notification 4 Sutsukuda Takan
Claims (1)
を前記絶縁体の先端から突出して軸孔に嵌め込まれる中
心電極と からなり、前記中心電極の先端と前記主体金具の先端部
との間に火花放電間隙を形成する内燃機関のスパークプ
ラグにおいて、 前記中心電極の先端は径大鍔状部となり、 Ａを絶縁体の先端の直径、Ｂを径大鍔状部の先端面の直
径、Ｃを絶縁体の脚長部の寸法Ｆの先端側１／３位置に
おける絶縁体の外径、Ｊを軸孔内の中心電極の直径、Ｅ
を絶縁体先端から径大鍔状部までの距離とした場合、 前記径大鍔状部の先端面の直径Ｂは、 Ａ＜Ｂ≦Ｃ×１．２およびＢ≦Ｊ×３．０を満たし、か
つ、 絶縁体先端から径大鍔状部までの距離Ｅは、０（ｍｍ）
≦Ｅ≦５（ｍｍ）を満たすことをことを特徴とする内燃
機関のスパークプラグ。[Scope of Claims] 1) Consisting of a cylindrical metal shell, an insulator with a shaft hole fitted into the metal shell, and a center electrode whose tip protrudes from the tip of the insulator and is fitted into the shaft hole, In a spark plug for an internal combustion engine that forms a spark discharge gap between the tip of the center electrode and the tip of the metal shell, the tip of the center electrode is a large-diameter flange-shaped portion, and A is the diameter of the tip of the insulator. , B is the diameter of the distal end surface of the large-diameter brim, C is the outer diameter of the insulator at the distal 1/3 position of the long leg dimension F of the insulator, J is the diameter of the center electrode in the shaft hole, and E
When is the distance from the tip of the insulator to the large-diameter flanged portion, the diameter B of the tip surface of the large-diameter flanged portion satisfies A<B≦C×1.2 and B≦J×3.0. , and the distance E from the tip of the insulator to the large diameter flange is 0 (mm)
A spark plug for an internal combustion engine, characterized in that it satisfies ≦E≦5 (mm).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2468289A JPH02204988A (en) | 1989-02-02 | 1989-02-02 | Spark plug of internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2468289A JPH02204988A (en) | 1989-02-02 | 1989-02-02 | Spark plug of internal combustion engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02204988A true JPH02204988A (en) | 1990-08-14 |
Family
ID=12144923
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2468289A Pending JPH02204988A (en) | 1989-02-02 | 1989-02-02 | Spark plug of internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02204988A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2696453A1 (en) * | 2012-08-08 | 2014-02-12 | NGK Spark Plug Co., Ltd. | Spark plug |
| JP2021012794A (en) * | 2019-07-04 | 2021-02-04 | 株式会社デンソー | Spark plug for internal combustion and internal combustion having the same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5439734A (en) * | 1977-09-05 | 1979-03-27 | Ngk Spark Plug Co Ltd | Spark plug |
-
1989
- 1989-02-02 JP JP2468289A patent/JPH02204988A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5439734A (en) * | 1977-09-05 | 1979-03-27 | Ngk Spark Plug Co Ltd | Spark plug |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2696453A1 (en) * | 2012-08-08 | 2014-02-12 | NGK Spark Plug Co., Ltd. | Spark plug |
| US9172215B2 (en) | 2012-08-08 | 2015-10-27 | Ngk Spark Plug Co., Ltd. | Spark plug having center electrode tip of varying widths |
| JP2021012794A (en) * | 2019-07-04 | 2021-02-04 | 株式会社デンソー | Spark plug for internal combustion and internal combustion having the same |
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