JP2000040577A - Spark plug and its manufacture - Google Patents
Spark plug and its manufactureInfo
- Publication number
- JP2000040577A JP2000040577A JP10205472A JP20547298A JP2000040577A JP 2000040577 A JP2000040577 A JP 2000040577A JP 10205472 A JP10205472 A JP 10205472A JP 20547298 A JP20547298 A JP 20547298A JP 2000040577 A JP2000040577 A JP 2000040577A
- Authority
- JP
- Japan
- Prior art keywords
- ground electrode
- chip
- tip
- electrode
- spark plug
- 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
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 22
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 18
- 239000000956 alloy Substances 0.000 claims abstract description 18
- 239000000463 material Substances 0.000 claims abstract description 18
- 230000004927 fusion Effects 0.000 claims abstract description 14
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 5
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 4
- 238000003466 welding Methods 0.000 claims description 31
- 238000002844 melting Methods 0.000 claims description 8
- 230000008018 melting Effects 0.000 claims description 8
- 239000000470 constituent Substances 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 abstract 1
- 239000002184 metal Substances 0.000 abstract 1
- 239000012212 insulator Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 3
- 238000005304 joining Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910000575 Ir alloy Inorganic materials 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 239000010970 precious metal Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910001260 Pt alloy Inorganic materials 0.000 description 1
- 229910000629 Rh alloy Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000009933 burial Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 229910001026 inconel Inorganic materials 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000002040 relaxant effect Effects 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Landscapes
- Spark Plugs (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、内燃機関の燃焼室
等に設置されるスパークプラグおよびその製造方法に関
し、特に、接地電極への貴金属チップの接合に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spark plug installed in a combustion chamber or the like of an internal combustion engine and a method of manufacturing the same, and more particularly, to joining a noble metal tip to a ground electrode.
【０００２】[0002]
【従来の技術】一般に、スパークプラグは、取付金具内
に絶縁体を介して絶縁保持された中心電極と、取付金具
に接合された接地電極とを備える。そして、中心電極の
絶縁体から露出した部分と接地電極とを対向させ、この
対向部（火花放電部）に、火花放電が行われる放電ギャ
ップを形成する。さらに、プラグの長寿命、高性能化の
ために、放電ギャップにおいて中心電極及び接地電極の
少なくとも一方の対向面に、火花放電部電極材としての
貴金属チップを溶接する。2. Description of the Related Art In general, a spark plug includes a center electrode insulated and held in a mounting bracket via an insulator, and a ground electrode joined to the mounting bracket. Then, a portion of the center electrode exposed from the insulator is opposed to the ground electrode, and a discharge gap where a spark discharge is performed is formed in the opposed portion (spark discharge portion). Further, in order to extend the life of the plug and improve the performance, a noble metal tip as a spark discharge portion electrode material is welded to at least one of the opposite surfaces of the center electrode and the ground electrode in the discharge gap.
【０００３】そのようなものとして、従来より米国特許
第４，７７１，２１０号明細書に記載のような貴金属を
配した接地電極が提案されている。これは、接地電極に
おいて放電ギャップ側の対向面からこれと反対側の面に
連通する穴を設け、この連通穴に棒状の貴金属チップを
貫通させ、かしめ固定、あるいはレーザ溶接、アルゴン
溶接を行なうことにより、接地電極に貴金属チップを配
するものである。As such, a ground electrode provided with a noble metal as described in US Pat. No. 4,771,210 has been proposed. This is because a ground electrode is provided with a hole communicating from the opposite surface on the discharge gap side to the opposite surface, a rod-shaped noble metal tip is penetrated into this communication hole, and caulking and fixing, or laser welding or argon welding is performed. Thus, a noble metal tip is arranged on the ground electrode.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、本発明
者等の検討によれば、上記従来技術においては、穴の連
通加工は高い精度が要求されるため、生産性が良くな
い。また、チップにおいて放電ギャップに位置する必要
部分の他に、連通穴に貫通させる分の貴金属が必要とな
るため、全体として貴金属の使用量が多くなり、コスト
が高くなるという問題が生じる。However, according to the study of the present inventors, in the above-mentioned prior art, since high precision is required for the continuous machining of holes, productivity is not good. Further, in addition to the required portion of the chip located at the discharge gap, a precious metal is required to penetrate the communication hole, so that the use amount of the precious metal is increased as a whole, and the cost is increased.
【０００５】そこで、本発明は上記点に鑑みて、接地電
極に貴金属チップを設けたスパークプラグにおいて、生
産性に優れ、かつ、貴金属の使用量を最小限に抑えた安
価なプラグを提供すること、及びそのようなプラグを製
造する製造方法を提供することを目的とする。In view of the above, the present invention has been made to provide an inexpensive spark plug in which a noble metal tip is provided on a ground electrode, which is excellent in productivity and minimizes the amount of noble metal used. , And a method of manufacturing such a plug.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するた
め、請求項１記載の発明においては、接地電極（４）に
接合される貴金属製のチップ（５２）が、接地電極
（４）の中心電極（３）と対向する対向面（４ｂ）に配
置され、接地電極（４）における対向面（４ｂ）とは反
対側の反対面（４ｃ）からチップ（５２）に向かって、
接地電極（４）とチップ（５２）の互いの構成材料が溶
融した材料よりなる溶融部（６０）が形成されているこ
とを特徴としている。In order to achieve the above object, according to the first aspect of the present invention, a noble metal tip (52) joined to a ground electrode (4) is provided at the center of the ground electrode (4). It is arranged on the opposing surface (4b) opposing the electrode (3), and from the opposing surface (4c) of the ground electrode (4) opposite to the opposing surface (4b) toward the chip (52).
It is characterized in that a fusion part (60) made of a material in which the constituent materials of the ground electrode (4) and the tip (52) are fused is formed.
【０００７】本発明によれば、チップ（５２）は接地電
極（４）の対向面（４ｂ）に配置され、上記溶融部（６
０）により接地電極（４）に接合されているから、従来
のような上記連通穴及び該連通穴に配置する分のチップ
の貴金属が不要とできる。よって、生産性に優れ、か
つ、貴金属の使用量を最小限に抑えた安価なプラグを提
供することができる。According to the present invention, the tip (52) is arranged on the surface (4b) facing the ground electrode (4), and the melting portion (6) is provided.
Since it is joined to the ground electrode (4) by 0), the communication hole and the noble metal of the chip to be disposed in the communication hole as in the related art can be dispensed with. Therefore, it is possible to provide an inexpensive plug that is excellent in productivity and minimizes the amount of noble metal used.
【０００８】また、請求項２記載の発明のように、溶融
部（６０）は、その厚みが接地電極（４）の反対面（４
ｃ）側で厚く、対向面（４ｂ）に向かって薄くなってい
るものにできる。また、請求項３記載の発明のように、
接地電極（４）はＮｉ基合金より構成され、チップ（５
２）はＩｒを主成分とする合金より構成され、溶融部
（６０）はＮｉとＩｒとの合金を主成分とする材料より
なるものにできる。Further, as in the second aspect of the present invention, the thickness of the fusion zone (60) is opposite to that of the ground electrode (4).
It can be thicker on the c) side and thinner toward the facing surface (4b). Also, as in the invention according to claim 3,
The ground electrode (4) is made of a Ni-based alloy, and has a tip (5).
2) is made of an alloy containing Ir as a main component, and the molten portion (60) can be made of a material containing an alloy of Ni and Ir as a main component.
【０００９】また、請求項４ないし請求項６記載の発明
は製造方法に関するものである。請求項４記載の発明に
おいては、チップ（５２）を接地電極（４）の中心電極
（３）と対向する対向面（４ｂ）に配置し、接地電極
（４）における対向面（４ｂ）とは反対側の反対面（４
ｃ）から接地電極（４）を介してレーザ溶接することに
より、接地電極（４）とチップ（５２）とを溶融させる
ことを特徴としている。The inventions according to claims 4 to 6 relate to a manufacturing method. In the invention described in claim 4, the chip (52) is arranged on the opposing surface (4b) of the ground electrode (4) opposing the center electrode (3), and the opposing surface (4b) of the ground electrode (4) is different from the opposing surface (4b). Opposite side (4
The method is characterized in that the ground electrode (4) and the chip (52) are melted by laser welding from c) via the ground electrode (4).
【００１０】それによって、従来のように連通穴を開け
ることなく、接地電極（４）における対向面（４ｂ）の
反対面（４ｃ）からチップ（５２）に向かって、接地電
極（４）とチップ（５２）の互いの構成材料が溶融した
材料よりなる溶融部（６０）を形成できる。よって、請
求項１記載のプラグと同様の作用効果を奏するプラグを
提供できるとともに、そのようなプラグを製造する製造
方法を提供できる。Accordingly, the ground electrode (4) and the chip (52) are moved from the surface (4c) of the ground electrode (4) opposite to the opposing surface (4b) toward the chip (52) without forming a communication hole as in the prior art. A molten portion (60) made of a material obtained by melting the constituent materials of (52) can be formed. Therefore, it is possible to provide a plug having the same operation and effect as the plug according to the first aspect, and to provide a manufacturing method for manufacturing such a plug.
【００１１】また、請求項５記載の発明においては、チ
ップ（５２）を接地電極（４）の対向面（４ｂ）に配置
した後、抵抗溶接により対向面（４ｂ）にチップ（５
２）を仮固定することを特徴としている。それにより、
レーザ溶接の際にチップ（５２）が対向面（４ｂ）に仮
固定されているから、両者を固定する別体の治具等が不
要となり、レーザ溶接の作業性を向上させることができ
る。In the invention according to claim 5, after the tip (52) is disposed on the facing surface (4b) of the ground electrode (4), the tip (5) is placed on the facing surface (4b) by resistance welding.
2) is temporarily fixed. Thereby,
Since the tip (52) is temporarily fixed to the opposing surface (4b) during laser welding, a separate jig or the like for fixing both is not required, and the workability of laser welding can be improved.
【００１２】また、請求項６記載の発明は、チップ（５
２）を対向面（４ｂ）に押しつけるように加圧しつつ抵
抗溶接を行い、チップ（５２）の一部を接地電極（４）
に埋没させることにより仮固定を行なうことを特徴とす
るもので、請求項５記載の仮固定の具体的手段を提供す
ることができる。なお、上記した括弧内の符号は、後述
する実施形態記載の具体的手段との対応関係を示す一例
である。Further, according to the present invention, the chip (5)
2) Resistance welding is performed while pressing so as to press against the opposing surface (4b), and a part of the tip (52) is grounded to the ground electrode (4).
The temporary fixing is performed by being buried in the slab, and specific means for temporary fixing according to claim 5 can be provided. In addition, the code | symbol in a parenthesis mentioned above is an example which shows the correspondence with the concrete means of embodiment described later.
【００１３】[0013]
【発明の実施の形態】以下、本発明を図に示す実施形態
について説明する。本実施形態のスパークプラグは、例
えばエンジンの燃焼室内に一部が露出するようにエンジ
ンブロックに取り付けられるものに適用される。図１
は、本実施形態に係るスパークプラグ１００の全体構成
を示す半断面図である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. The spark plug according to the present embodiment is applied to, for example, a spark plug that is attached to an engine block so that a part thereof is exposed in a combustion chamber of an engine. FIG.
FIG. 1 is a half sectional view showing the entire configuration of a spark plug 100 according to the present embodiment.
【００１４】スパークプラグ１００は、円筒形状の取付
金具１を有しており、この取付金具１は、図示しないエ
ンジンブロックに固定するための取付ネジ部１ａを備え
ている。取付金具１の内部には、アルミナセラミック
（Ａｌ2 Ｏ3 ）等からなる絶縁体２が固定されており、
この絶縁体２の先端部２ａは、取付金具１から露出する
ように設けられている。The spark plug 100 has a cylindrical mounting bracket 1, and the mounting bracket 1 has a mounting screw portion 1a for fixing to an engine block (not shown). An insulator 2 made of alumina ceramic (Al 2 O 3 ) or the like is fixed inside the mounting bracket 1.
The tip 2 a of the insulator 2 is provided so as to be exposed from the mounting bracket 1.
【００１５】絶縁体２の軸孔２ｂには中心電極３が固定
されており、この中心電極３は取付金具１に対して絶縁
保持されている。中心電極３は、内材がＣｕ等の熱伝導
性に優れた金属材料、外材がＮｉ基合金等の耐熱性およ
び耐食性に優れた金属材料により構成された円柱体で、
図１に示すように、その先端部３ａが絶縁体２の先端部
２ａから露出するように設けられている。A center electrode 3 is fixed to the shaft hole 2 b of the insulator 2, and the center electrode 3 is insulated from the mounting bracket 1. The center electrode 3 is a cylindrical body whose inner material is made of a metal material having excellent thermal conductivity such as Cu, and whose outer material is made of a metal material having excellent heat resistance and corrosion resistance such as a Ni-based alloy.
As shown in FIG. 1, the distal end 3 a is provided so as to be exposed from the distal end 2 a of the insulator 2.
【００１６】一方、接地電極４は、一端側の固定部４ａ
にて取付金具１の一端に溶接により固定され、途中で略
Ｌ字に曲げられて、固定部４ａとは反対端部の対向面４
ｂにおいて中心電極３の先端部３ａと放電ギャップ６を
隔てて対向している。ここで、図２は（ａ）は接地電極
４の対向面４ｂ近傍の拡大斜視図、（ｂ）は（ａ）のＹ
矢視図である。On the other hand, the ground electrode 4 is connected to a fixed portion 4a at one end.
Is fixed to one end of the mounting bracket 1 by welding, and is bent in a substantially L-shape on the way, and the facing surface 4 at the end opposite to the fixing portion 4a.
b, it is opposed to the tip 3a of the center electrode 3 with the discharge gap 6 therebetween. Here, FIG. 2A is an enlarged perspective view of the vicinity of the facing surface 4b of the ground electrode 4, and FIG.
It is an arrow view.
【００１７】接地電極４は、Ｎｉを主成分とするＮｉ基
合金（例えばインコネル（登録商標））より構成され、
全長が例えば約１０ｍｍの断面偏平（図２中、例えば幅
Ｗが約２．６ｍｍ、厚さＨが約１．４ｍｍ）の角柱が、
略Ｌ字に曲げられた形状を成す。そして、中心電極３の
先端部３ａには、貴金属チップ５１がレーザ溶接により
固定されている。このチップ５１は円盤状であり、中心
電極３の先端部３ａの円柱端面に接合されている。The ground electrode 4 is made of a Ni-based alloy containing Ni as a main component (for example, Inconel (registered trademark)).
A prism having a flattened cross section with a total length of, for example, about 10 mm (in FIG. 2, for example, a width W of about 2.6 mm and a thickness H of about 1.4 mm),
It has a shape bent into a substantially L-shape. A noble metal tip 51 is fixed to the tip 3a of the center electrode 3 by laser welding. The tip 51 has a disk shape and is joined to the end face 3a of the center electrode 3 at the end of the column.
【００１８】一方、接地電極４の対向面４ｂには、略円
柱状をなす貴金属チップ５２がレーザ溶接により固定配
置されている。これら両チップ５１、５２は、Ｉｒを主
成分とするＩｒ合金（例えばＩｒが９０重量％、Ｒｈが
１０重量％のＩｒ−１０Ｒｈ合金）からなる。ここで、
上記の放電ギャップ６は両チップ５１、５２の隙間であ
り、例えば約１ｍｍである。On the other hand, a substantially columnar noble metal tip 52 is fixedly disposed on the facing surface 4b of the ground electrode 4 by laser welding. These chips 51 and 52 are made of an Ir alloy containing Ir as a main component (for example, an Ir-10Rh alloy containing 90% by weight of Ir and 10% by weight of Rh). here,
The discharge gap 6 is a gap between the chips 51 and 52 and is, for example, about 1 mm.
【００１９】ここで、本発明の要部である接地電極４側
のチップ５２について、図２及び図３を参照して更に詳
細に述べる。図３は図２（ｂ）のＡ−Ａ断面図である。
チップ５２の形状は特に限定しないが、本例では、例え
ば直径Ｄが約０．７ｍｍ、長さＬが約０．６ｍｍである
円盤に近い円柱体であり、円柱長手方向において、チッ
プ５２の一部が対向面４ｂに埋没した形となっている。
このチップ５２の埋没深さＭ１は、例えば約０．５ｍｍ
である。Here, the chip 52 on the ground electrode 4 side, which is a main part of the present invention, will be described in more detail with reference to FIGS. FIG. 3 is a sectional view taken along line AA of FIG.
Although the shape of the tip 52 is not particularly limited, in the present example, the tip 52 is a cylindrical body close to a disk having a diameter D of about 0.7 mm and a length L of about 0.6 mm. The portion is buried in the facing surface 4b.
The burial depth M1 of the chip 52 is, for example, about 0.5 mm.
It is.
【００２０】そして、チップ５２と接地電極４とが溶融
したＮｉとＩｒとの合金を主成分とする合金からなる溶
融部６０が、接地電極４の内部にて、対向面４ｂの反対
面４ｃからチップ５２の一部に入り込んで形成されてい
る。図３に示す様に、溶融部６０は略半楕円状であり、
その厚み（半楕円の短径方向の長さ）が反対面４ｃ側で
厚く、対向面４ｂに向かって薄くなっている。A melted portion 60 made of an alloy mainly composed of an alloy of Ni and Ir in which the tip 52 and the ground electrode 4 are melted is formed inside the ground electrode 4 from the opposite surface 4c of the opposing surface 4b. It is formed to penetrate a part of the chip 52. As shown in FIG. 3, the fusion part 60 is substantially semi-elliptical.
The thickness (the length of the semi-ellipse in the minor axis direction) is thicker on the opposite surface 4c side and thinner toward the opposite surface 4b.
【００２１】ここで、図３に示す溶融部６０の各部寸法
の一例を示しておく。接地電極４の厚さＨ方向に沿った
溶融部６０の長さＫ１は、約１．１ｍｍであり、溶融部
６０においてチップ５２の一部に入り込んだ入り込み長
さＭ２は、約０．２ｍｍである。また、接地電極４の反
対面４ｃに平行方向である溶融部６０の厚さＫ２は、約
１．０ｍｍである。Here, an example of the dimensions of each portion of the fusion zone 60 shown in FIG. 3 will be described. The length K1 of the fusion part 60 along the thickness H direction of the ground electrode 4 is about 1.1 mm, and the penetration length M2 of a part of the chip 52 in the fusion part 60 is about 0.2 mm. is there. Further, the thickness K2 of the melted portion 60 that is parallel to the opposite surface 4c of the ground electrode 4 is about 1.0 mm.
【００２２】かかる構成を有するスパークプラグ１００
の製造方法のうち、接地電極４とチップ５２との接合方
法について述べる。なお、同製造方法のうち他の部分の
製造工程については、周知であるため説明を省略する。
通常は、取付金具１に接地電極４を固定した状態でチッ
プ５２をレーザ溶接するが、接地電極４単独の状態で行
ってもよい。The spark plug 100 having such a configuration
The method of joining the ground electrode 4 and the chip 52 among the manufacturing methods described above will be described. In addition, the manufacturing process of the other parts in the manufacturing method is well known, and thus the description is omitted.
Normally, the tip 52 is laser-welded with the ground electrode 4 fixed to the mounting bracket 1, but may be performed with the ground electrode 4 alone.
【００２３】まず、チップ５２を接地電極４の対向面４
ｂに配置し、レーザ溶接を行う前に、チップ５２を仮固
定する。仮固定は、チップ５２を対向面４ｂに押しつけ
るように、治具等を用いて加圧しつつ抵抗溶接を行い、
チップ５２の一部を接地電極４に埋没させることにより
行なう。ここで、抵抗溶接の条件は、例えば荷重３０ｋ
ｇｆ、電流８５０Ａ（アンペア）とできる。First, the chip 52 is connected to the opposing surface 4 of the ground electrode 4.
Before performing laser welding, the chip 52 is temporarily fixed. The temporary fixing is performed by resistance welding while pressing with a jig or the like so as to press the chip 52 against the opposing surface 4b.
This is performed by burying a part of the chip 52 in the ground electrode 4. Here, the condition of the resistance welding is, for example, a load of 30 k.
gf and a current of 850 A (ampere).
【００２４】このとき、例えばＩｒ合金からなるチップ
５２の融点は約２５００℃、Ｎｉ基合金からなる接地電
極４の融点は約１５００℃〜１６００℃であり、母材と
なる接地電極４の方が抵抗溶接時に軟らかくなって凹
み、チップ５２の一部が対向面４ｂに埋没する。なお、
チップ５２の位置合わせのために、予め接地電極４の対
向面４ｂに窪み等の加工をしてチップ５２の設置を容易
としてもよい。At this time, for example, the melting point of the tip 52 made of an Ir alloy is about 2500 ° C., the melting point of the ground electrode 4 made of a Ni-based alloy is about 1500 ° C. to 1600 ° C., and the ground electrode 4 serving as a base material has a lower melting point. At the time of resistance welding, the chip becomes soft and dented, and a part of the tip 52 is buried in the facing surface 4b. In addition,
In order to align the chip 52, a concave or the like may be formed on the facing surface 4b of the ground electrode 4 in advance to facilitate installation of the chip 52.
【００２５】続いて、図３に示す白抜き矢印Ｒ方向か
ら、レーザ溶接を行う。ここで、レーザ溶接条件は、例
えばエネルギーが６０Ｊ（パルス幅が２０ｍｓｅｃ、充
電電圧が４２０Ｖ）、デフォーカスが＋２ｍｍ（つまり
レーザの焦点がチップ５２の照射面よりも２ｍｍ奥にあ
る）、レーザのビーム径がφ０．４ｍｍとした。例えば
このような条件にて連続照射（例えば３発）することに
より、上記溶融部６０が形成され、接地電極４とチップ
５２との接合が行われる。Subsequently, laser welding is performed from the direction of the white arrow R shown in FIG. Here, the laser welding conditions include, for example, an energy of 60 J (pulse width of 20 msec, charging voltage of 420 V), a defocus of +2 mm (that is, the focal point of the laser is 2 mm deeper than the irradiation surface of the chip 52), and a laser beam. The diameter was 0.4 mm. For example, by performing continuous irradiation (for example, three shots) under such conditions, the melting portion 60 is formed, and the bonding between the ground electrode 4 and the tip 52 is performed.
【００２６】ところで、本実施形態によれば、チップ５
２は接地電極４の対向面４ｂに配置され、溶融部６０に
より接地電極４に接合されているから、従来のような上
記連通穴及び該連通穴に配置する分のチップの貴金属が
不要とできる。よって、生産性に優れ、かつ、貴金属の
使用量を最小限に抑えた安価なプラグを提供することが
できる。According to the present embodiment, the chip 5
2 is disposed on the opposing surface 4b of the ground electrode 4 and is joined to the ground electrode 4 by the fusion portion 60, so that the communication hole and the noble metal of the chip to be disposed in the communication hole as in the related art can be unnecessary. . Therefore, it is possible to provide an inexpensive plug that is excellent in productivity and minimizes the amount of noble metal used.
【００２７】また、本実施形態によれば、接地電極４の
放電面である対向面４ｂの反対側の反対面４ｃから溶接
しているため、放電面側に耐消耗性の悪い溶融部が存在
せず、長寿命、高性能な接地電極構成が実現できる。ま
た、本実施形態ではレーザを反対面４ｃから照射してい
るから、レーザのエネルギー分布により、溶融部６０
は、その厚みが接地電極４の反対面４ｃ側で厚く、対向
面４ｂに向かって薄くなっているものにできる。Further, according to the present embodiment, since the welding is performed from the opposite surface 4c opposite to the opposite surface 4b which is the discharge surface of the ground electrode 4, there is a molten portion having poor wear resistance on the discharge surface side. Without this, a long-life, high-performance ground electrode configuration can be realized. In this embodiment, since the laser is irradiated from the opposite surface 4c, the melting portion 60
Can be thicker on the opposite surface 4c side of the ground electrode 4 and thinner toward the opposing surface 4b.
【００２８】また、本実施形態によれば、チップ５２を
接地電極４対向面４ｂに配置し、接地電極４の反対面４
ｃから接地電極４を介してレーザ溶接することにより、
接地電極４とチップ５２とを溶融させ、両者を接合する
から、従来のように連通穴を開けることなく、生産性に
優れ、かつ、貴金属の使用量を最小限に抑えた安価なプ
ラグ製造方法を提供できる。Further, according to the present embodiment, the chip 52 is disposed on the surface 4 b facing the ground electrode 4, and
By performing laser welding from c through the ground electrode 4,
Since the ground electrode 4 and the tip 52 are melted and the two are joined, an inexpensive plug manufacturing method that is excellent in productivity and minimizes the amount of noble metal used without forming a communication hole as in the related art. Can be provided.
【００２９】また、本実施形態によれば、レーザ溶接の
前に、抵抗溶接によりチップ５２の一部を接地電極４に
埋没させつつ、チップ５２と接地電極４との界面を溶接
することにより、対向面４ｂにチップ５２を仮固定する
ようにしているから、レーザ溶接の際に両者を固定する
別体の治具等が不要となり、レーザ溶接の作業性を向上
させることができる。According to the present embodiment, before laser welding, the interface between the tip 52 and the ground electrode 4 is welded while a part of the tip 52 is buried in the ground electrode 4 by resistance welding. Since the tip 52 is temporarily fixed to the opposing surface 4b, a separate jig or the like for fixing the both is not required at the time of laser welding, and the workability of laser welding can be improved.
【００３０】また、本実施形態によれば、チップ５２と
接地電極４とは、レーザ溶接によって両者の構成材料が
十分に溶融した溶融部６０により接合されているから、
接合部において熱応力を緩和し、高信頼性を有するスパ
ークプラグを提供することができる。また、それによっ
て、プラグ交換時間の大幅拡大が図れ、長寿命のスパー
クプラグを実現でき、さらには、熱負荷の厳しい環境で
使用されるスパークプラグを提供できる。Further, according to the present embodiment, the tip 52 and the ground electrode 4 are joined by the molten portion 60 in which both constituent materials are sufficiently melted by laser welding.
It is possible to provide a spark plug having high reliability by relaxing thermal stress at the joint. In addition, the plug replacement time can be significantly extended, and a long-life spark plug can be realized. Further, a spark plug used in an environment where a heat load is severe can be provided.
【００３１】（他の実施形態）なお、チップ５２は、上
記円柱状に限定されるものではなく、図４（ａ）ないし
（ｈ）に示すような形状であってもよい。ここで、図４
において、（ｂ）、（ｄ）、（ｆ）、（ｈ）は、各々、
（ａ）、（ｃ）、（ｅ）、（ｇ）のＡ−Ａ断面図であ
る。また、これら断面図において、溶融部６０と重なる
部分のチップ５２の形状も、便宜上示してある。(Other Embodiments) The tip 52 is not limited to the above-mentioned cylindrical shape, but may be shaped as shown in FIGS. 4 (a) to 4 (h). Here, FIG.
In (b), (d), (f), and (h),
It is AA sectional drawing of (a), (c), (e), (g). Further, in these cross-sectional views, the shape of the chip 52 at a portion overlapping with the fusion zone 60 is also shown for convenience.
【００３２】即ち、チップ５２は、円柱状であって円柱
の対向面４ｂの埋没側端面から突出する脚部５２ａを有
するもの（図４（ａ））、円柱状であって円柱の円周面
を対向面４ｂに埋没させたもの（図４（ｂ））、三角柱
（図４（ｃ））または四角柱（図４（ｄ））であってそ
の側面に沿った角柱稜線を対向面４ｂと略平行に配置す
るものであってもよい。That is, the tip 52 has a columnar shape and has legs 52a protruding from the buried-side end face of the opposing surface 4b of the cylinder (FIG. 4 (a)). Is buried in the opposing surface 4b (FIG. 4B), a triangular prism (FIG. 4C) or a quadrangular prism (FIG. 4D). They may be arranged substantially in parallel.
【００３３】また、チップ５２の材質はＩｒ−Ｒｈ合金
に限定されるものではなく、その他、例えば、Ｉｒ−Ｒ
ｈ−Ｐｔ合金等でもよい。また、接地電極の材質もＮｉ
を主成分とするＮｉ基合金に限定されず、耐熱性に優れ
たものであればよい。また、チップ５２と接地電極４と
の接合方法は、レーザ溶接に限定されず、可能であるな
らば、他の溶接方法（抵抗溶接、アーク溶接等）、ある
いは反対面４ｃから溶融部６０を形成できるような熱等
のエネルギーを付与する方法を用いてもよい。The material of the tip 52 is not limited to the Ir-Rh alloy, but may be other materials such as Ir-R.
An h-Pt alloy may be used. The material of the ground electrode is also Ni.
The alloy is not limited to a Ni-based alloy containing, as a main component, any material having excellent heat resistance may be used. The method of joining the tip 52 and the ground electrode 4 is not limited to laser welding, and if possible, another welding method (resistance welding, arc welding, etc.) or forming the fusion zone 60 from the opposite surface 4c. A method of applying energy such as heat as possible may be used.
【図１】本発明の実施形態に係るスパークプラグの全体
構成を示す半断面図である。FIG. 1 is a half sectional view showing an overall configuration of a spark plug according to an embodiment of the present invention.
【図２】（ａ）は図１における接地電極の対向面近傍の
拡大斜視図、（ｂ）は（ａ）のＹ矢視図である。2A is an enlarged perspective view of the vicinity of a facing surface of a ground electrode in FIG. 1, and FIG. 2B is a view taken in the direction of the arrow Y in FIG.
【図３】図２（ｂ）のａ−ａ断面図である。FIG. 3 is a sectional view taken along line aa of FIG. 2 (b).
【図４】本発明の貴金属チップの他の形状を示す図であ
る。FIG. 4 is a view showing another shape of the noble metal tip of the present invention.
【符号の説明】 １…取付金具、３…中心電極、４…接地電極、４ｂ…接
地電極の対向面、４ｃ…接地電極の反対面、６…放電ギ
ャップ、５２…チップ、６０…溶融部。[Description of Symbols] 1 ... mounting bracket, 3 ... center electrode, 4 ... ground electrode, 4b ... ground electrode facing surface, 4c ... ground electrode opposite surface, 6 ... discharge gap, 52 ... chip, 60 ... fusion zone.
Claims (6)
放電ギャップ（６）を隔てて対向する対向面（４ｂ）を
有する接地電極（４）とを備え、 前記接地電極（４）に貴金属製のチップ（５２）が接合
されているスパークプラグにおいて、 前記チップ（５２）は前記接地電極（４）の前記対向面
（４ｂ）に配置されており、 前記接地電極（４）における前記対向面（４ｂ）とは反
対側の反対面（４ｃ）から前記チップ（５２）に向かっ
て、前記接地電極（４）と前記チップ（５２）の互いの
構成材料が溶融した材料よりなる溶融部（６０）が形成
されていることを特徴とするスパークプラグ。1. A center electrode (3), a fitting (1) for insulating and holding the center electrode (3), and a discharge gap (6) fixed to the fitting (1) and connected to the center electrode (3). And a ground electrode (4) having a facing surface (4b) opposed to the spark plug with a noble metal tip (52) joined to the ground electrode (4). Is disposed on the opposing surface (4b) of the ground electrode (4), and from the opposite surface (4c) of the ground electrode (4) opposite to the opposing surface (4b) to the chip (52). A spark plug is characterized in that a fused portion (60) made of a material obtained by melting the constituent materials of the ground electrode (4) and the tip (52) is formed toward the ground electrode (4).
接地電極（４）の前記反対面（４ｃ）側で厚く、前記対
向面（４ｂ）に向かって薄くなっていることを特徴とす
る請求項１に記載のスパークプラグ。2. The fusion part (60) is characterized in that the thickness thereof is thicker on the side of the opposite side (4c) of the ground electrode (4) and thinner toward the opposite side (4b). The spark plug according to claim 1, wherein
成され、前記チップ（５２）はＩｒを主成分とする合金
より構成され、 前記溶融部（６０）はＮｉとＩｒとの合金を主成分とす
る材料より構成されていることを特徴とする請求項１ま
たは２に記載のスパークプラグ。3. The ground electrode (4) is made of a Ni-based alloy, the tip (52) is made of an alloy containing Ir as a main component, and the molten portion (60) is made of an alloy of Ni and Ir. The spark plug according to claim 1, wherein the spark plug is made of a material that is a main component.
電ギャップ（６）を介して対向させ、前記接地電極
（４）の前記中心電極（３）と対向する対向面（４ｂ）
に貴金属製のチップ（５２）を溶接してなるスパークプ
ラグの製造方法であって、 前記チップ（５２）を前記対向面（４ｂ）に配置し、 前記接地電極（４）における前記対向面（４ｂ）とは反
対側の反対面（４ｃ）から前記接地電極（４）を介して
レーザ溶接することにより、前記接地電極（４）と前記
チップ（５２）とを溶融させることを特徴とするスパー
クプラグの製造方法。4. A center electrode (3) and a ground electrode (4) are opposed to each other via a discharge gap (6), and a facing surface (4b) of the ground electrode (4) facing the center electrode (3).
A method for producing a spark plug, comprising welding a noble metal tip (52) to a ground electrode (4), wherein the tip (52) is arranged on the facing surface (4b), and the facing surface (4b) in the ground electrode (4) is provided. ), The ground electrode (4) and the tip (52) are melted by laser welding from the opposite surface (4c) opposite to the ground electrode (4). Manufacturing method.
ｂ）に配置した後、抵抗溶接により前記対向面（４ｂ）
に前記チップ（５２）を仮固定することを特徴とする請
求項４に記載のスパークプラグの製造方法。5. The chip (52) is connected to the facing surface (4).
b), and then, by resistance welding, the opposing surface (4b).
The method for producing a spark plug according to claim 4, wherein the tip (52) is temporarily fixed to the spark plug.
ｂ）に押しつけるように加圧しつつ前記抵抗溶接を行
い、前記チップ（５２）の一部を前記接地電極（４）に
埋没させることにより前記仮固定を行なうことを特徴と
する請求項５に記載のスパークプラグの製造方法。6. The chip (52) is attached to the facing surface (4).
6. The temporary fixing according to claim 5, wherein the resistance welding is performed while applying pressure so as to press against the b), and a part of the tip (52) is buried in the ground electrode (4). Spark plug manufacturing method.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20547298A JP3820756B2 (en) | 1998-07-21 | 1998-07-21 | Spark plug and manufacturing method thereof |
| US09/324,860 US6337533B1 (en) | 1998-06-05 | 1999-06-03 | Spark plug for internal combustion engine and method for manufacturing same |
| DE19925672A DE19925672B4 (en) | 1998-06-05 | 1999-06-04 | spark plug |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20547298A JP3820756B2 (en) | 1998-07-21 | 1998-07-21 | Spark plug and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000040577A true JP2000040577A (en) | 2000-02-08 |
| JP3820756B2 JP3820756B2 (en) | 2006-09-13 |
Family
ID=16507436
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20547298A Expired - Lifetime JP3820756B2 (en) | 1998-06-05 | 1998-07-21 | Spark plug and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3820756B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6642638B2 (en) | 2000-07-10 | 2003-11-04 | Denso Corporation | Spark plug with Ir-alloy chip |
| JP2005123167A (en) * | 2003-09-27 | 2005-05-12 | Ngk Spark Plug Co Ltd | Spark plug |
| US7045939B2 (en) | 2001-03-19 | 2006-05-16 | Ngk Spark Plug Co., Ltd. | Spark plug having a welded electrode and the method of producing the same |
| US7154213B2 (en) | 2003-09-24 | 2006-12-26 | Denso Corporation | Ground electrode structure of a spark plug for a gas engine |
| JP2011113978A (en) * | 2009-11-23 | 2011-06-09 | Robert Bosch Gmbh | Spark plug ground electrode having multilayer structure, and method of manufacturing the same |
| WO2014097983A1 (en) * | 2012-12-17 | 2014-06-26 | 日本特殊陶業株式会社 | Spark plug |
| WO2017203742A1 (en) | 2016-05-24 | 2017-11-30 | 日本特殊陶業株式会社 | Spark plug and production method therefor |
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|---|---|---|---|---|
| JP4928596B2 (en) | 2009-12-04 | 2012-05-09 | 日本特殊陶業株式会社 | Spark plug and manufacturing method thereof |
| EP3621165B1 (en) | 2010-09-29 | 2021-11-24 | NGK Spark Plug Co., Ltd. | Spark plug |
-
1998
- 1998-07-21 JP JP20547298A patent/JP3820756B2/en not_active Expired - Lifetime
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6642638B2 (en) | 2000-07-10 | 2003-11-04 | Denso Corporation | Spark plug with Ir-alloy chip |
| US7045939B2 (en) | 2001-03-19 | 2006-05-16 | Ngk Spark Plug Co., Ltd. | Spark plug having a welded electrode and the method of producing the same |
| US7154213B2 (en) | 2003-09-24 | 2006-12-26 | Denso Corporation | Ground electrode structure of a spark plug for a gas engine |
| JP2005123167A (en) * | 2003-09-27 | 2005-05-12 | Ngk Spark Plug Co Ltd | Spark plug |
| JP2011113978A (en) * | 2009-11-23 | 2011-06-09 | Robert Bosch Gmbh | Spark plug ground electrode having multilayer structure, and method of manufacturing the same |
| JP5895056B2 (en) * | 2012-12-17 | 2016-03-30 | 日本特殊陶業株式会社 | Spark plug |
| WO2014097983A1 (en) * | 2012-12-17 | 2014-06-26 | 日本特殊陶業株式会社 | Spark plug |
| US9935430B2 (en) | 2012-12-17 | 2018-04-03 | Ngk Spark Plug Co., Ltd. | Spark plug |
| WO2017203742A1 (en) | 2016-05-24 | 2017-11-30 | 日本特殊陶業株式会社 | Spark plug and production method therefor |
| JP2017212063A (en) * | 2016-05-24 | 2017-11-30 | 日本特殊陶業株式会社 | Spark plug and manufacturing method thereof |
| CN109155504A (en) * | 2016-05-24 | 2019-01-04 | 日本特殊陶业株式会社 | Spark plug and method of making the same |
| US10367335B2 (en) | 2016-05-24 | 2019-07-30 | Ngk Spark Plug Co., Ltd. | Spark plug and production method therefor |
| EP3467974A4 (en) * | 2016-05-24 | 2020-01-08 | NGK Spark Plug Co., Ltd. | SPARK PLUG AND PRODUCTION METHOD THEREFOR |
| CN109155504B (en) * | 2016-05-24 | 2020-03-06 | 日本特殊陶业株式会社 | Spark plug and method of making the same |
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| Publication number | Publication date |
|---|---|
| JP3820756B2 (en) | 2006-09-13 |
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