JPH0417284A - Heater-attached spark plug - Google Patents

Heater-attached spark plug

Info

Publication number
JPH0417284A
JPH0417284A JP12046490A JP12046490A JPH0417284A JP H0417284 A JPH0417284 A JP H0417284A JP 12046490 A JP12046490 A JP 12046490A JP 12046490 A JP12046490 A JP 12046490A JP H0417284 A JPH0417284 A JP H0417284A
Authority
JP
Japan
Prior art keywords
insulator
heater
lead
ceramic
lead 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.)
Granted
Application number
JP12046490A
Other languages
Japanese (ja)
Other versions
JP2892103B2 (en
Inventor
Yoshihiro Matsubara
佳弘 松原
Koji Amano
天野 孝二
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 JP12046490A priority Critical patent/JP2892103B2/en
Publication of JPH0417284A publication Critical patent/JPH0417284A/en
Application granted granted Critical
Publication of JP2892103B2 publication Critical patent/JP2892103B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Abstract

PURPOSE:To prevent short-circuit between a lead electrode and a main body metal fitting with a simple structure and prevent the lead electrode from being peeled off of an insulator by coating the lead electrode with an electrically insulating ceramic. CONSTITUTION:A heater-attached spark plug A is composed of a cylindrical main body metal fitting 1 and an insulator 2 having a shaft hole 21 and fit in the metal fitting and a ceramic heater 3 unitedly bound to a long leg part 22 of the insulator 2. Also, a pair of lead electrodes 4, 5 are stuck to the surface of the insulator of the long leg part 22 and a center electrode 6 is inserted into and fixed in the shaft hole 21. The lead electrodes 4, 5 are covered with an electrically insulating ceramic. Consequently, short-circuit between the lead electrodes 4, 5 and the main body metal fitting 1, flash-over of the lead electrodes 4, 5 into the inside, and peeling the lead electrodes 4, 5 due to heat are prevented.

Description

【発明の詳細な説明】 [産業上の利用分野コ 本発明は、絶縁体の汚損対策、難着火燃料を使用する内
燃機関の低温始動性の向上のため、絶縁体の脚長部にセ
ラミックヒータを配設したスパークプラグに関する。
[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a ceramic heater in the long leg portion of the insulator in order to prevent contamination of the insulator and improve low-temperature startability of an internal combustion engine that uses hard-to-ignite fuel. Regarding the installed spark plug.

[従来の技術] 絶縁体脚長部にセラミックヒータを配設したヒータ付ス
パークプラグにおいて、ヒータ通電用のリード電極は、
露出状態(基底部等を除く)に絶縁体に被着されている
[Prior art] In a spark plug with a heater in which a ceramic heater is arranged in the long leg of the insulator, the lead electrode for energizing the heater is
The exposed state (excluding the base etc.) is covered with an insulator.

[発明が解決しようとする課題] しかるに、従来のヒータ付スパークプラグは、つぎのよ
うな欠点を有する。
[Problems to be Solved by the Invention] However, the conventional spark plug with a heater has the following drawbacks.

(あ)主体金具にリード電極がショートし易い。(A) Lead electrodes tend to short-circuit to the metal shell.

(い)セラミックヒータが発生する熱でリード電極が絶
縁体から剥離し易い。
(b) The lead electrode easily peels off from the insulator due to the heat generated by the ceramic heater.

(う)リード電極への内部フラッシュオーバーが起こり
易い。
(c) Internal flashover to the lead electrode is likely to occur.

本発明の目的は、簡単な構成でリード電極と主体金具と
のショートが防止でき、かつリード電極が絶縁体から容
易に剥離しないヒータ付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 with a heater that can prevent short circuits between lead electrodes and a metal shell with a simple configuration, and in which the lead electrodes do not easily peel off from the insulator.

[課題宝解決するための手段〕 上記目的を達成するため、本発明は、筒状の主体金具と
、該主体金具に嵌め込まれる軸孔材の絶縁体と、電気発
熱体をセラミック絶縁層で被覆してなり前記絶縁体の脚
長部に一体的に結合されるセラミックヒータと、先端が
前記セラミックヒータに電気接続され、後端がヒータ通
電部となり、前記絶縁体表面に膜付けされる1組のリー
ド電極と、前記軸孔に差し込まれて固定される中心電極
とを備えてなるヒータ付スパークプラグにおいて前記ヒ
ータ通電部の中央を除いて、前記リード電極を電気絶縁
性セラミックで被覆した構成を採用した。
[Means for Solving the Problems] In order to achieve the above object, the present invention provides a cylindrical metal shell, an insulator of a shaft hole material fitted into the metal shell, and an electric heating element covered with a ceramic insulating layer. a ceramic heater which is integrally connected to the long leg portion of the insulator; and a pair of ceramic heaters whose tip end is electrically connected to the ceramic heater, whose rear end serves as a heater current-carrying part, and which is coated with a film on the surface of the insulator. In a heater-equipped spark plug comprising a lead electrode and a center electrode inserted into and fixed in the shaft hole, the lead electrode is coated with electrically insulating ceramic except for the center of the heater current-carrying part. did.

[作用および発明の効果] リード電極を電気絶縁性セラミックで被覆することによ
り、リード電極と主体金具とのショート、リード電極へ
の内部フラッシュオーバー、熱によるリード電極の剥離
がそれぞれ防止できる。なお、リード電極の真上だけで
なく、リード電極の周辺まで被覆をすることにより、さ
らに上記の効果は高まる。
[Operations and Effects of the Invention] By covering the lead electrode with electrically insulating ceramic, short circuit between the lead electrode and the metal shell, internal flashover to the lead electrode, and peeling of the lead electrode due to heat can be prevented. Note that the above effect is further enhanced by covering not only the area directly above the lead electrode but also the periphery of the lead electrode.

ヒータ通電部の外周および通電部の周辺を電気絶縁性セ
ラミックで被覆することにより、ヒータ通電部と絶縁体
との接合強度が増大する。なお、ヒータ通電部の中央は
、給電のために露出させている。
By covering the outer periphery of the heater current-carrying part and the periphery of the current-carrying part with electrically insulating ceramic, the bonding strength between the heater current-carrying part and the insulator is increased. Note that the center of the heater current-carrying part is exposed for power supply.

[実施例] つぎに、本発明の一実施例を第1図に基づき説明する。[Example] Next, one embodiment of the present invention will be described based on FIG.

第1図に示す如く、ヒータ付スパークプラグAは、筒状
の主体金具1に軸孔21付の絶縁体2を嵌め込み、絶縁
体2の脚長部22にセラミックヒータ3を一体的に結合
してなる。また、前記脚長部22の絶縁体表面には、1
組のリード電極4.5が絶縁体表面に膜付けされている
。さらに、前記軸孔21には中心電極6が差し込まれて
固定されている。
As shown in FIG. 1, the heater-equipped spark plug A is constructed by fitting an insulator 2 with a shaft hole 21 into a cylindrical main metal fitting 1, and integrally connecting a ceramic heater 3 to a long leg portion 22 of the insulator 2. Become. In addition, on the insulator surface of the long leg portion 22, 1
A set of lead electrodes 4.5 is filmed on the surface of the insulator. Furthermore, the center electrode 6 is inserted into the shaft hole 21 and fixed therein.

主体金具1(低炭素鋼製)は、後端の六角部11、先端
のねじ部12、中間の胴部13からなる。
The metal shell 1 (made of low carbon steel) includes a hexagonal part 11 at the rear end, a threaded part 12 at the tip, and a body part 13 in the middle.

六角部11は、六角状に加工され、内側に滑石リング、
線パツキンを装入して前記絶縁体2を固定している。
The hexagonal part 11 is processed into a hexagonal shape, and has a talcum ring inside,
The insulator 2 is fixed by inserting a wire packing.

ねじ部12は、機関取付けねじを外周に形成し、先端面
には外側電極14が溶接されている。また、ねじ部12
の内壁にはテーバ状のパツキン接触面15が形成され、
該接触面15には金属製のパツキン16が周設されてい
る。
The threaded portion 12 has an engine mounting screw formed on its outer periphery, and an outer electrode 14 is welded to the tip surface. In addition, the threaded portion 12
A tapered packing contact surface 15 is formed on the inner wall of the
A metal packing 16 is provided around the contact surface 15.

絶縁体2は、アルミナを主体とするセラミック焼結体で
形成され、先端が前記脚長部22、後端がコルゲーショ
ン部24、中間は胴部25となっている。
The insulator 2 is formed of a ceramic sintered body mainly made of alumina, and has the long leg portion 22 at the tip, the corrugated portion 24 at the rear end, and the body portion 25 in the middle.

脚長部22は、径小に形成され、テーバ状の基底23を
前記パツキン16に当接している。
The long leg portion 22 is formed to have a small diameter, and has a tapered base 23 in contact with the packing 16 .

コルゲーション部24(やや径大)は、フラッシュオー
バー防止のため、後端にコルゲーションを形成している
The corrugation portion 24 (slightly large in diameter) has a corrugation formed at the rear end to prevent flashover.

胴部25(径大)は、フランジ状を呈し、段部を介して
先端がやや径小に形成されている。
The body portion 25 (large diameter) has a flange shape, and the tip is formed with a slightly smaller diameter through a stepped portion.

セラミックヒータ3は、電気発熱体を、セラミック絶縁
層であるアルミナで被覆してなる。このセラミックヒー
タ3は、絶縁体2の脚長部22に波状に形成されている
The ceramic heater 3 is formed by covering an electric heating element with alumina, which is a ceramic insulating layer. This ceramic heater 3 is formed in a wavy shape on the long leg portion 22 of the insulator 2.

リード電極4は、先端41が前記セラミックヒータ3に
電気接続され、後端がヒータ通電部42となっている。
The lead electrode 4 has a tip 41 electrically connected to the ceramic heater 3 and a rear end serving as a heater current-carrying portion 42 .

このヒータ通電部42は前記パツキン16に当接され主
体金具1と電気的導通が図られている。
This heater current-carrying portion 42 is brought into contact with the packing 16 to establish electrical continuity with the metal shell 1.

リード電ri!5は、先端51が前記セラミックヒータ
3に電気接続され、後端はコルゲーション部24まで延
設されてヒータ通電部52となっている。このヒータ通
電部52は給電端子(図示せず)により掴持される。
Lead Denri! 5 has a tip 51 electrically connected to the ceramic heater 3, and a rear end extending to the corrugation portion 24 to form a heater current-carrying portion 52. This heater current-carrying portion 52 is held by a power supply terminal (not shown).

これらリード電極4.5は、前記ヒータ通電部42.5
2の中央を除き、電気絶縁性セラミックであるアルミナ
7で被覆されている。
These lead electrodes 4.5 are connected to the heater current-carrying portion 42.5.
All parts except the center of 2 are coated with alumina 7, which is an electrically insulating ceramic.

中心電極6は、ニッケル合金で形成され、前記絶縁体2
の先端面から僅か突出している。
The center electrode 6 is made of a nickel alloy, and the insulator 2
It protrudes slightly from the tip.

つぎに、ヒータ付スパークプラグAの製造方法(要部)
を説明する。
Next, the manufacturing method of spark plug A with heater (main part)
Explain.

(1)金属粉末とアルミナ粉末とを調合し、バインダー
を加え、前記電気発熱体およびリード電極4.5用のペ
ーストを製造する。
(1) Mix metal powder and alumina powder, add a binder, and produce a paste for the electric heating element and lead electrode 4.5.

(2)電気発熱体用のペーストを未焼成絶縁体の脚長部
に波形状に印刷する。
(2) Print the paste for the electric heating element in a wave shape on the long legs of the green insulator.

(3)先端が上記電気発熱体用のペーストの一端を覆い
、後端が前記基底23に達するように、リード電極4用
のペーストを、脚長部に印刷する。また、先端が上記電
気発熱体用のペーストの他端を覆い、後端が未焼成絶縁
体のコルゲーション部に達する−ように、リード電極5
用のペーストを印刷する。
(3) Print the paste for the lead electrode 4 on the long leg part so that the leading end covers one end of the paste for the electric heating element and the rear end reaches the base 23. In addition, the lead electrode 5 is arranged so that the tip covers the other end of the paste for the electric heating element and the rear end reaches the corrugation part of the unfired insulator.
Print the paste for.

(4)アルミナ粉末にバインダーを加えてアルミナペー
ストを製造する。上記電気発熱体用のペースト上、およ
びリード電極4.5用のペースト上に、このアルミナペ
ーストを塗布する。なお、リード電極4.5用のペース
トが十分被覆されるように、該ペーストの周辺にもアル
ミナペーストを塗布する。ただし、ヒータ通電部42.
52となる部分の中央部には塗布しない。
(4) Add a binder to alumina powder to produce alumina paste. This alumina paste is applied on the paste for the electric heating element and on the paste for the lead electrodes 4.5. Note that alumina paste is also applied around the paste for lead electrodes 4.5 so that the paste is sufficiently covered. However, the heater energizing section 42.
Do not apply to the center of the part marked 52.

(5)この未焼成絶縁体を焼成して、セラミックヒータ
3、およびアルミナ7を被覆したリード電極4.5を有
する絶縁体2が完成する。
(5) This unfired insulator is fired to complete the insulator 2 having the ceramic heater 3 and the lead electrodes 4.5 covered with alumina 7.

つぎに、ヒータ付スパークプラグAの作用効果を説明す
る。
Next, the effects of the heater-equipped spark plug A will be explained.

(ア)リード電極4.5は、アルミナ7で被覆されてい
るので、主体金具1と容易にショートしない。
(a) Since the lead electrode 4.5 is coated with alumina 7, it does not easily short-circuit with the metal shell 1.

(イ)セラミックヒータ3により絶縁体2は通常のスパ
ークプラグより高温になる。しかし、リード電極4.5
は、アルミナ7で被覆されているので、容易に絶縁体2
から剥がれたりしない。このため、ヒータ付スパークプ
ラグAは耐久性に優れる。
(a) The ceramic heater 3 makes the insulator 2 hotter than a normal spark plug. However, the lead electrode 4.5
is coated with alumina 7, so it can be easily attached to the insulator 2.
It will not peel off. Therefore, the heater-equipped spark plug A has excellent durability.

(つ)脚長部22に位置するリード電極4.5への内部
フラッシュオーバーが極めて起こり難い。
(1) Internal flashover to the lead electrode 4.5 located on the long leg portion 22 is extremely unlikely to occur.

(1)ヒータ通電部42.52の外周部もアルミナ7で
被覆されているので、通電部42.52がパツキン16
や給電端子から機械的な応力を受けても容易に絶縁体2
から剥がれない。
(1) Since the outer periphery of the heater current-carrying portion 42.52 is also coated with alumina 7, the current-carrying portion 42.52 is covered with the gasket 16.
Even if mechanical stress is applied from the power supply terminal or the
It cannot be peeled off.

(オ)リード電極4.5は、アルミナ7により絶縁体2
と強固に固着される。このため、ペースト材料を広範囲
に選べる。
(E) The lead electrode 4.5 has an insulator 2 made of alumina 7.
is firmly fixed. Therefore, a wide range of paste materials can be selected.

(力)リード電極4.5と主体金具1とのショートを防
止するための、絶縁体2や主体金具1の構造変更は不要
である。
(Force) It is not necessary to change the structure of the insulator 2 or the metal shell 1 in order to prevent a short circuit between the lead electrode 4.5 and the metal shell 1.

(キ)未焼成絶縁体に、電気発熱体およびリード電極4
.5用のペーストを印刷し、さらにアルミナ7用のペー
ストを塗布しているので、電気発熱体用のペーストおよ
びリード電極4.5用のペーストが飛散したり、昇華し
たりしない。
(g) Electric heating element and lead electrode 4 on the unfired insulator
.. Since the paste for Alumina 7 is printed and the paste for Alumina 7 is applied, the paste for the electric heating element and the paste for the lead electrode 4.5 do not scatter or sublimate.

本発明は、上記実施例以外につぎの実施態様を含む。The present invention includes the following embodiments in addition to the above embodiments.

a、リード電極の電気絶縁性セラミックでの被覆は、焼
成(絶縁体、リード電極、セラミックヒータ)の完了し
た後に、PVD?CVDにより行っても良い。
a. The lead electrode is coated with electrically insulating ceramic by PVD after firing (insulator, lead electrode, ceramic heater) is completed. It may also be performed by CVD.

b、電気絶縁性セラミックは、絶縁体の材料に応じ、適
宜法めれば良い。
b. The electrically insulating ceramic may be used as appropriate depending on the material of the insulator.

C3上記実施例ではリード電極4が、パツキン16と電
気接続される構成であるが、リード電極5と同様にコル
ゲーション部24まで、延設されていても良い。
C3 Although the lead electrode 4 is electrically connected to the packing 16 in the above embodiment, it may be extended to the corrugation portion 24 similarly to the lead electrode 5.

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

第1図は本発明の一実施例を示すヒータ付スパークプラ
グの部分断面図である。
FIG. 1 is a partial sectional view of a spark plug with a heater showing an embodiment of the present invention.

Claims (1)

【特許請求の範囲】 1)筒状の主体金具と、 該主体金具に嵌め込まれる軸孔付の絶縁体と、電気発熱
体をセラミック絶縁層で被覆してなり、前記絶縁体の脚
長部に一体的に結合されるセラミックヒータと、 先端が前記セラミックヒータに電気接続され、後端がヒ
ータ通電部となり、前記絶縁体表面に膜付けされる1組
のリード電極と、 前記軸孔に差し込まれて固定される中心電極とを備えて
なるヒータ付スパークプラグにおいて、前記ヒータ通電
部の中央を除いて、前記リード電極を電気絶縁性セラミ
ックで被覆したことを特徴とするヒータ付スパークプラ
グ。
[Scope of Claims] 1) A cylindrical metal shell, an insulator with a shaft hole fitted into the metal shell, and an electric heating element covered with a ceramic insulating layer, and integrated into the long leg portion of the insulator. a pair of lead electrodes, the tip of which is electrically connected to the ceramic heater, the rear end of which serves as a heater current-carrying part, and which is coated on the surface of the insulator; and a pair of lead electrodes that are inserted into the shaft hole. 1. A spark plug with a heater comprising a fixed center electrode, characterized in that the lead electrode is coated with electrically insulating ceramic except for the center of the heater current-carrying part.
JP12046490A 1990-05-10 1990-05-10 Spark plug with heater Expired - Lifetime JP2892103B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12046490A JP2892103B2 (en) 1990-05-10 1990-05-10 Spark plug with heater

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12046490A JP2892103B2 (en) 1990-05-10 1990-05-10 Spark plug with heater

Publications (2)

Publication Number Publication Date
JPH0417284A true JPH0417284A (en) 1992-01-22
JP2892103B2 JP2892103B2 (en) 1999-05-17

Family

ID=14786816

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12046490A Expired - Lifetime JP2892103B2 (en) 1990-05-10 1990-05-10 Spark plug with heater

Country Status (1)

Country Link
JP (1) JP2892103B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8707922B2 (en) 2009-12-15 2014-04-29 Federal Mogul Ignition Company Spark ignition device for an internal combustion engine and central electrode assembly therefor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8707922B2 (en) 2009-12-15 2014-04-29 Federal Mogul Ignition Company Spark ignition device for an internal combustion engine and central electrode assembly therefor
US10027092B2 (en) 2009-12-15 2018-07-17 Federal-Mogul Ignition Company Spark ignition device for an internal combustion engine and central electrode assembly therefore

Also Published As

Publication number Publication date
JP2892103B2 (en) 1999-05-17

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