WO2014189088A1 - Method for manufacturing spark plug for internal combustion engine - Google Patents

Method for manufacturing spark plug for internal combustion engine Download PDF

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Publication number
WO2014189088A1
WO2014189088A1 PCT/JP2014/063507 JP2014063507W WO2014189088A1 WO 2014189088 A1 WO2014189088 A1 WO 2014189088A1 JP 2014063507 W JP2014063507 W JP 2014063507W WO 2014189088 A1 WO2014189088 A1 WO 2014189088A1
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Prior art keywords
base material
discharge
electrode
chip
spark plug
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PCT/JP2014/063507
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French (fr)
Japanese (ja)
Inventor
勇樹 村山
阿部　信男
弘一 坂入
邦弘 田中
Original Assignee
株式会社デンソー
田中貴金属工業株式会社
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Application filed by 株式会社デンソー, 田中貴金属工業株式会社 filed Critical 株式会社デンソー
Priority to CN201480028953.7A priority Critical patent/CN105247747B/en
Priority to EP14801406.1A priority patent/EP3001519B1/en
Publication of WO2014189088A1 publication Critical patent/WO2014189088A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
    • H01T13/39—Selection of materials for electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T21/00—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs
    • H01T21/02—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs of sparking plugs

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  • the present invention relates to a method of manufacturing a spark plug for an internal combustion engine, in which at least one of a center electrode and a ground electrode that are opposed to each other with a spark discharge gap formed therebetween is provided with a discharge tip.
  • a high efficiency engine that performs supercharging with a low displacement is required.
  • These high-efficiency engines employ a high-performance spark plug having a discharge chip at least one of the center electrode and the ground electrode in order to improve ignition performance.
  • a noble metal such as Pt, Ir, Ru, Rh, Pd, Os or a rare metal is used in order to ensure wear resistance.
  • a spark plug in which a discharge chip is constituted by a composite material (Clad Material) of a base material joint portion joined to an electrode base material and a discharge portion facing a spark discharge gap.
  • Patent Document 1 discloses a method of manufacturing a discharge chip made of a composite material formed by joining a base material joint and a discharge part by resistance welding and diffusion bonding. It is disclosed.
  • the discharge chip (clad electrode) described in Patent Document 1 has the following problems. That is, since this discharge chip is obtained by joining the discharge part and the base material joint part, a step is likely to occur between them. Therefore, a sharp corner portion of the base material joint portion is likely to appear on the side portion of the discharge chip. Then, when this discharge chip is used for the ground electrode or the center electrode of the spark plug, the electric field strength near the sharp corner of the base material joint becomes high. Therefore, the discharge spark tends to fly to the sharp corners of the base material joint at the side of the discharge chip, and it may be difficult to form a normal discharge spark.
  • a discharge chip is produced by punching out a composite plate obtained by bonding the material of the discharge part and the material of the base material joint part, a discharge chip without a step between the discharge part and the base material joint part can be obtained. Is possible. However, when the composite plate after being punched is regenerated, it is necessary to separate the two kinds of materials, and there is a problem that the regeneration cost increases. On the contrary, when the discharge part and the base material joint part are joined after punching, the diameter of the base material joint part is made larger than the diameter of the discharge part in order to make the joint area of both constant. There is a need. As a result, a step is generated between the base material joined portion and the discharge portion, and a sharp corner portion of the base material joined portion is formed on the side portion of the discharge chip.
  • the present invention has been made in view of such a background, and an object of the present invention is to provide a method for manufacturing a spark plug for an internal combustion engine that can suppress a spark to a base material joint.
  • the present invention provides a discharge chip in which at least one of a center electrode and a ground electrode which are opposed to each other with a spark discharge gap formed therebetween is bonded to an electrode base material so as to protrude toward the spark discharge gap.
  • a method of manufacturing a spark plug for an internal combustion engine is provided. This method A discharge part disposed on the spark discharge gap side and a base material joint part made of a material having a melting point lower than that of the discharge part and joined to the electrode base material are joined together to produce the discharge chip.
  • Chip manufacturing process A temporary joining step of temporarily joining the discharge tip to the electrode base material at the base material joint by resistance welding; The main joining which joins the said discharge chip to the said electrode base material so that the side surface of the said discharge part and the surface of the said electrode base material may be smoothly connected with the connection surface which does not have a sharp edge by laser welding. And a process.
  • a sharp corner portion of the base material joint portion does not appear on the side portion of the discharge chip. That is, it is possible to prevent a portion where the electric field strength is locally increased from being formed in the base material joint. As a result, it is possible to suppress sparks to the base material joint.
  • the discharge chip can be easily joined to the electrode base material so that the side surface of the discharge part and the surface of the electrode base material are smoothly connected.
  • FIG. 1 The side view of the front-end
  • FIG. 1 The (a) front view and (b) top view of the discharge chip obtained by the chip
  • FIG. The front view which shows the state which carried out the temporary joining of the discharge chip to the electrode base material by the temporary joining process in Example 1.
  • FIG. The front view which shows the state which welded the discharge tip to the electrode base material by the main joining process in Example 1.
  • FIG. Sectional explanatory drawing which shows the state which welded the discharge tip to the electrode base material by the main joining process in Example 2.
  • FIG. Sectional explanatory drawing which shows the
  • the center electrode may include the discharge tip, the ground electrode may include the discharge tip, or both the center electrode and the ground electrode may include the discharge tip. You may have.
  • the spark plug can be used as ignition means in a combustion chamber of an internal combustion engine such as an automobile engine.
  • the discharge chip obtained in the chip manufacturing process may have a diameter of the base material joint portion larger than a diameter of the discharge portion. In this case, it is easy to stably join the discharge portion and the base material joint portion in the chip manufacturing process. However, when the diameter of the base material joint is larger than the diameter of the discharge part, a step is generated between the two, and a sharp corner of the base material joint appears. If the discharge tip is bonded to the electrode base material with the sharp corners still appearing, the sparks of the spark plug are likely to fly to the base material bonding portion.
  • the discharge chip and the electrode base material are joined to the electrode base material so that the side surface of the discharge portion and the surface of the electrode base material are smoothly connected by a connection surface having no sharp edge.
  • a connection surface having no sharp edge it is possible to take a sharp corner of the base material joint.
  • the spark to the base material junction part can be suppressed effectively.
  • Example 1 Examples of the method for manufacturing a spark plug for the internal combustion engine will be described with reference to FIGS.
  • the spark plug 1 obtained by the manufacturing method of this example has a spark discharge gap 11 in which a center electrode 2 and a ground electrode 3 that are opposed to each other with a spark discharge gap 11 formed therebetween.
  • Discharge chips 4 and 5 joined to the electrode base materials 20 and 30 so as to protrude toward the surface, respectively.
  • the discharge tip 5 in the ground electrode 3 is made of a discharge part 51 disposed on the spark discharge gap 11 side, and a base material joined to the electrode base material 30 while being made of a material having a melting point lower than that of the discharge part 51.
  • the joining portion 52 is joined to each other.
  • the discharge tip 4 in the center electrode 2 is not a composite member.
  • the manufacturing method of the spark plug 1 of this example includes a chip manufacturing process, a temporary bonding process, and a main bonding process described below. That is, the ground electrode 3 formed by joining the discharge chip 5 to the electrode base material 30 is formed through the following steps.
  • the chip manufacturing process as shown in FIG. 2, the discharge part 5 and the base material bonding part 52 are bonded together to manufacture the discharge chip 5.
  • the temporary joining step the discharge chip 5 is temporarily joined to the electrode base material 30 at the base material joint portion 52 by resistance welding as shown in FIG.
  • the main joining step as shown in FIG. 4, by melting and solidifying a part of the base material joining part 52 and a part of the electrode base material 30 by laser welding, the side surface 511 and the electrode of the discharge part 51 are solidified.
  • the discharge chip 5 is joined to the electrode base material 30 so that the surface of the base material 30 is smoothly connected to the connection surface 523 having no sharp edge.
  • the electrode base material 30 of the ground electrode 3 extends from the distal end of the housing 12 of the spark plug 1 to the distal end side (lower side in FIG. 1) and is bent toward the central axis.
  • the electrode base material 20 of the center electrode 2 is held inside the insulator 13 held inside the housing 12.
  • Both the housing 12 and the electrode base material 30 of the ground electrode 3 are made of a nickel alloy.
  • the electrode base material 20 of the center electrode 2 is also made of a nickel alloy.
  • the electrode base material 30 of the ground electrode 3 includes a facing surface 31 that faces the center electrode 2 in the axial direction of the spark plug 1 (hereinafter simply referred to as “plug axial direction”).
  • the discharge chip 5 is joined.
  • the discharge chip 4 is joined to the tip of the electrode base material 20 of the center electrode 2 facing the facing surface 31 in the plug axis direction.
  • the discharge tip 4 of the center electrode 2 is not a composite member but is made of a noble metal tip such as an iridium alloy. That is, the discharge tip 4 made of a noble metal is joined to the tip of the electrode base material 20 of the center electrode 2 by welding or the like.
  • the discharge chip 5 of the ground electrode 3 is composed of a composite member in which the discharge part 51 and the base material joining part 52 are joined to each other as described above.
  • the above-described chip manufacturing process, provisional bonding process, and main bonding process are performed. An example of each process will be specifically described below.
  • a discharge part 51 made of a material having a relatively high melting point (for example, a melting point of 1700 ° C. or higher) and a base material joining part 52 made of a material having a lower melting point than the discharge part 51 are prepared.
  • a material having a relatively high melting point for example, a melting point of 1700 ° C. or higher
  • a base material joining part 52 made of a material having a lower melting point than the discharge part 51 are prepared.
  • the material of the discharge part 51 for example, Pt (platinum), Ir (iridium), Ru (ruthenium), Rh (rhodium), Pd (palladium), Os (osmium), or the like can be used.
  • a Ni (nickel) alloy can be used as this Ni alloy. As this Ni alloy, for example, one having a melting point of 1400 to 1450 ° C. can be used.
  • a cylindrical discharge part 51 and a base material joining part 52 are obtained.
  • the diameter of the base material joint 52 is larger than the diameter of the discharge part 51.
  • the cylindrical discharge portion 51 and the base material joint portion 52 formed in this way are overlapped in the axial direction while matching the central axes of both. And in the state which pressed both mutually, heat processing is performed and the discharge part 51 and the base material junction part 52 are joined by diffusion joining. Thereby, the discharge chip 5 as a composite member (Clad Material) is obtained.
  • a diffusion layer (not shown) in which atoms of the respective materials of the discharge part 51 and the base material bonding part 52 diffuse to each other. Is formed.
  • the diameter of the base material joint portion 52 is larger than the diameter of the discharge portion. Therefore, at this stage, a step is formed between the base material joint portion 52 and the discharge portion 51, and a sharp corner 521 of the base material joint portion 52 exists at this step portion.
  • the discharge chip 5 obtained in the chip manufacturing step is temporarily bonded to the facing surface 31 of the electrode base material 30 as shown in FIG.
  • Temporary joining is performed by resistance welding. That is, the discharge chip 5 is brought into contact with a predetermined position on the facing surface 31 of the electrode base material 30 on the surface on the base material joint portion 52 side.
  • a current is passed between the discharge tip 5 and the electrode base material 30 while the discharge tip 5 and the electrode base material 30 are sandwiched between the pair of resistance welding electrodes. Thereby, the discharge tip 5 is welded to the electrode base material 30 by Joule heat and temporarily joined.
  • the discharge tip 5 is joined to the electrode base material 30 by laser welding as shown in FIG. That is, as shown in FIG. 5, the laser light L is irradiated from the periphery of the joined portion to the discharge chip 5 temporarily joined to the electrode base material 30.
  • the laser light L is irradiated from a plurality of locations over the entire circumference of the joint portion with respect to the electrode base material 30.
  • laser welding is performed at a temperature lower than the melting point of the discharge part 51. That is, in the main joining step, the discharge part 51 is not melted, and a part of the base material joint part 52 and a part of the electrode base material 30 are melted.
  • a molten portion 522 in which the base material joint 52 and the electrode base material 30 are melted and solidified is formed in an annular shape on the outer periphery of the base material joint 52.
  • connection surface 523 that smoothly connects the surface of the electrode base material 30 (opposing surface 31) is formed.
  • the connection surface 523 has a shape in which a cross section of a plane passing through the central axis of the discharge chip 5 smoothly connects a curve and a straight line, and does not have a sharp edge.
  • the discharge chip 5 is joined to the electrode base material 30 by melting and solidifying a part of the base material joint portion 52 and a part of the electrode base material 30 by laser welding.
  • the discharge chip 5 is joined to the electrode base material 30 so that the side surface 511 of the discharge part 51 and the opposing surface 31 of the electrode base material 30 are connected by the connection surface 523 having no sharp edge. Therefore, in the spark plug 1 obtained, the sharpened corners 521 (FIG. 3) of the base material joint 52 do not appear on the side of the discharge chip 5, and the region where the electric field strength is locally increased is the base material. It is possible to prevent the joint portion 52 from being formed. As a result, sparks to the base material joint 52 can be suppressed.
  • the outer shape of the base material bonding portion 52 can be easily formed along the side surface 511 of the discharge portion 51 and the facing surface 31 of the electrode base material 30. Therefore, the discharge chip 5 is easily joined to the electrode base material 30 so that the side surface 511 of the discharge part 51 and the facing surface 31 of the electrode base material 30 are connected by the connection surface 523 having no sharp edge. Can do.
  • the diameter of the base material joint portion 52 is larger than the diameter of the discharge portion 51.
  • the diameter of the base material joint portion 52 is larger than the diameter of the discharge portion 51, a step is generated between them, and a sharp corner portion 521 of the base material joint portion 52 appears.
  • the discharge chip 5 is connected to the electrode base material so that the side surface 511 of the discharge part 51 and the facing surface 31 of the electrode base material 30 are connected by the connection surface 523 having no sharp edge.
  • the sharp corner 521 of the base material bonding portion 52 can be taken.
  • the side surface of the discharge chip 5 can be smoothly connected to the surface (opposite surface 31) of the electrode base material 30 from the side surface 511 of the discharge part 51 by the connection surface 523 which does not have a sharp edge. As a result, it is possible to effectively suppress the sparks to the base material joint 52.
  • the discharge tip 4 of the center electrode 2 is also composed of a discharge part 41 disposed on the spark discharge gap 11 side, a material having a melting point lower than that of the discharge part 41, and an electrode mother.
  • the base material joining portion 42 joined to the material 20 is composed of a composite material formed by joining together.
  • tip preparation process demonstrated in Example 1, the temporary joining process, and the main joining process are performed.
  • the discharge part 41 and the base material bonding part 42 are diffusion-bonded to obtain the discharge chip 4.
  • the discharge chip 4 is temporarily joined by resistance welding to the tip surface 21 of the electrode base material 20 of the center electrode 2 as shown in FIG. That is, the tip portion of the electrode base material 20 of the center electrode 2 before joining the discharge chip 4 has a substantially conical shape and has a flat surface whose tip is orthogonal to the axial direction.
  • the discharge chip 4 is temporarily bonded to the tip surface 21 which is a flat surface so that the base material bonding portion 42 side is brought into contact therewith.
  • the discharge tip 4 is joined to the electrode base material 20 by laser welding.
  • a melting portion 422 between the base material joint portion 42 of the discharge chip 4 and the electrode base material 20 is formed in an annular shape.
  • angular part 421 (FIG. 8) of the base material junction part 42 is removed geometrically as shown in FIG. 9, and the side surface 411 of the discharge part 41 and the surface (substantially conical part) of the electrode base material 20 are removed.
  • the connecting surface 423 is formed to smoothly connect the side surface 22).
  • the connection surface 423 has a shape in which a cross section of a plane passing through the central axis of the discharge chip 5 smoothly connects a curve and a straight line, and does not have a sharp edge.
  • Example 1 Others are the same as in Example 1.
  • the same reference numerals as those used in the first embodiment denote the same components as in the first embodiment unless otherwise specified.
  • the center electrode has the same configuration as that of the second embodiment, and the discharge tip of the ground electrode is made of a metal tip that is not a composite material, or the discharge tip is not provided on the ground electrode. You can also.

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Abstract

Provided is a method for manufacturing a spark plug (1) wherein at least either a central electrode (2) or a ground electrode (3) is provided with a discharge chip (5). In the chip manufacturing process, the discharge chip (5) is manufactured by bonding to each other a discharge portion (51) disposed on a spark discharge gap (11) side and a base material joint (52) made of a material with a melting point lower than the melting point of the discharge portion (51) and bonded to an electrode base material (30). In the temporary bonding process, the discharge chip (5) is temporarily bonded to the electrode base material (30) on the base material joint (52) by resistance welding. In the proper bonding process, the discharge chip (5) is bonded to the electrode base material (30) by laser welding so that the lateral surface (511) of the discharge portion (51) and the surface (31) of the electrode base material (30) can be smoothly bonded to each other through a bonding surface (523) having no pointed edge.

Description

内燃機関用のスパークプラグの製造方法Method of manufacturing a spark plug for an internal combustion engine
　本発明は、互いの間に火花放電ギャップを形成して対向配置された中心電極と接地電極との少なくとも一方が放電チップを備えている、内燃機関用のスパークプラグを製造する方法に関する。 The present invention relates to a method of manufacturing a spark plug for an internal combustion engine, in which at least one of a center electrode and a ground electrode that are opposed to each other with a spark discharge gap formed therebetween is provided with a discharge tip.
　自動車エンジン等の内燃機関においては、燃費向上のために、例えば、低排気量であって過給（Supercharging）を行う高効率エンジンが要求されている。これらの高効率エンジンには、点火性能の向上のために、中心電極及び接地電極の少なくとも何れか一方に放電チップ（Discharge　Chip）を有してなる高性能のスパークプラグが採用されている。 In an internal combustion engine such as an automobile engine, in order to improve fuel efficiency, for example, a high efficiency engine that performs supercharging with a low displacement is required. These high-efficiency engines employ a high-performance spark plug having a discharge chip at least one of the center electrode and the ground electrode in order to improve ignition performance.
　放電チップとしては、耐消耗性を確保すべく、例えばＰｔ、Ｉｒ、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ等の貴金属、またはレアメタルが用いられる。しかし、コスト低減及び資源の枯渇抑制の観点から、高融点材料の使用量の低減が重要課題として要請されている。この課題の対策として、放電チップを、電極母材と接合される母材接合部と、火花放電ギャップに面する放電部との複合材（Clad　Material）により構成したスパークプラグが提案されている。そして、特許文献１には、抵抗溶接（Resistance　Welding）と拡散接合(Diffusion　Bonding)とによって、母材接合部と放電部とを接合して形成される複合材からなる放電チップを製造する方法が開示されている。 As the discharge chip, for example, a noble metal such as Pt, Ir, Ru, Rh, Pd, Os or a rare metal is used in order to ensure wear resistance. However, from the viewpoint of cost reduction and resource depletion suppression, reduction of the amount of high melting point material used is an important issue. As a countermeasure for this problem, there has been proposed a spark plug in which a discharge chip is constituted by a composite material (Clad Material) of a base material joint portion joined to an electrode base material and a discharge portion facing a spark discharge gap. Patent Document 1 discloses a method of manufacturing a discharge chip made of a composite material formed by joining a base material joint and a discharge part by resistance welding and diffusion bonding. It is disclosed.
国際公開ＷＯ２０１３／０１５２６２号International Publication WO2013 / 015262
　しかしながら、上記特許文献１に記載の放電チップ（クラッド電極）には、以下の問題がある。すなわち、この放電チップは、放電部と母材接合部とを接合したものであるため、両者の間に段差が生じやすい。それゆえ、放電チップの側部に母材接合部の尖った角部が現れやすくなる。そうすると、この放電チップをスパークプラグの接地電極または中心電極に使用したとき、母材接合部の尖った角部付近の電界強度が高くなる。それゆえ、放電火花が放電チップの側部における母材接合部の尖った角部に飛びやすくなり、正常な放電火花を形成し難くなるおそれがある。 However, the discharge chip (clad electrode) described in Patent Document 1 has the following problems. That is, since this discharge chip is obtained by joining the discharge part and the base material joint part, a step is likely to occur between them. Therefore, a sharp corner portion of the base material joint portion is likely to appear on the side portion of the discharge chip. Then, when this discharge chip is used for the ground electrode or the center electrode of the spark plug, the electric field strength near the sharp corner of the base material joint becomes high. Therefore, the discharge spark tends to fly to the sharp corners of the base material joint at the side of the discharge chip, and it may be difficult to form a normal discharge spark.
　そこで、放電部と母材接合部との間の段差を無くせばよいが、特許文献１に記載の製造方法の場合、段差のない放電チップを得ることは困難である。つまり、上記製造方法においては、貴金属チップ（放電部）を抵抗溶接によってテープ状基材（母材接合部）に接合した後、基材と貴金属チップとが一体となった部分を打ち抜くため、貴金属チップと基材との間には段差が生じることとなる。つまり、打ち抜き後において、基材の直径が貴金属チップの直径よりも大きくすることとなる。 Therefore, it is only necessary to eliminate the step between the discharge part and the base material joint, but in the case of the manufacturing method described in Patent Document 1, it is difficult to obtain a discharge chip without a step. That is, in the above manufacturing method, the noble metal tip (discharge portion) is joined to the tape-like base material (base material joint portion) by resistance welding, and then the portion where the base material and the noble metal tip are integrated is punched. There will be a step between the chip and the substrate. That is, after punching, the diameter of the base material is larger than the diameter of the noble metal tip.
　また、放電部の材料と母材接合部の材料とを貼り合わせた複合板を打ち抜いて、放電チップを作製すれば、放電部と母材接合部との間の段差のない放電チップを得ることは可能である。しかし、打ち抜かれた後の複合板を再生する際に、２種類の材料を分離する必要が生じ、再生コストが高くなってしまうという問題がある。
　逆に、打ち抜いた後に、放電部と母材接合部とを接合する場合には、両者の接合面積を一定にするために、母材接合部の直径を放電部の直径よりも大きくしておく必要がある。その結果、母材接合部と放電部との間には段差が生じ、母材接合部の尖った角部が放電チップの側部に形成されることとなる。 Moreover, if a discharge chip is produced by punching out a composite plate obtained by bonding the material of the discharge part and the material of the base material joint part, a discharge chip without a step between the discharge part and the base material joint part can be obtained. Is possible. However, when the composite plate after being punched is regenerated, it is necessary to separate the two kinds of materials, and there is a problem that the regeneration cost increases.
On the contrary, when the discharge part and the base material joint part are joined after punching, the diameter of the base material joint part is made larger than the diameter of the discharge part in order to make the joint area of both constant. There is a need. As a result, a step is generated between the base material joined portion and the discharge portion, and a sharp corner portion of the base material joined portion is formed on the side portion of the discharge chip.
　本発明は、かかる背景に鑑みてなされたものであり、母材接合部への飛び火を抑制することができる内燃機関用のスパークプラグの製造方法を提供しようとするものである。 The present invention has been made in view of such a background, and an object of the present invention is to provide a method for manufacturing a spark plug for an internal combustion engine that can suppress a spark to a base material joint.
　本発明は、互いの間に火花放電ギャップを形成して対向配置された中心電極と接地電極との少なくとも一方が、上記火花放電ギャップに向かって突出するように電極母材に接合された放電チップを備えている、内燃機関用のスパークプラグを製造する方法を提供する。この方法は、
　上記火花放電ギャップ側に配される放電部と、該放電部よりも融点の低い材料からなると共に上記電極母材と接合される母材接合部とを、互いに接合して上記放電チップを作製するチップ作製工程と、
　抵抗溶接によって、上記放電チップを上記母材接合部において上記電極母材に仮接合する仮接合工程と、
　レーザ溶接によって、上記放電部の側面と上記電極母材の表面とが尖ったエッジ（Edge）を有しない連結面により滑らかに連結されるように上記放電チップを上記電極母材に接合する本接合工程と
を有することを特徴とする。 The present invention provides a discharge chip in which at least one of a center electrode and a ground electrode which are opposed to each other with a spark discharge gap formed therebetween is bonded to an electrode base material so as to protrude toward the spark discharge gap. A method of manufacturing a spark plug for an internal combustion engine is provided. This method
A discharge part disposed on the spark discharge gap side and a base material joint part made of a material having a melting point lower than that of the discharge part and joined to the electrode base material are joined together to produce the discharge chip. Chip manufacturing process;
A temporary joining step of temporarily joining the discharge tip to the electrode base material at the base material joint by resistance welding;
The main joining which joins the said discharge chip to the said electrode base material so that the side surface of the said discharge part and the surface of the said electrode base material may be smoothly connected with the connection surface which does not have a sharp edge by laser welding. And a process.
　上記の方法によれば、得られるスパークプラグにおいて、放電チップの側部に母材接合部の尖った角部が現れることはない。つまり、電界強度が局部的に高くなる部位が母材接合部に形成されることを防ぐことができる。その結果、母材接合部への飛び火を抑制することができる。 According to the above method, in the obtained spark plug, a sharp corner portion of the base material joint portion does not appear on the side portion of the discharge chip. That is, it is possible to prevent a portion where the electric field strength is locally increased from being formed in the base material joint. As a result, it is possible to suppress sparks to the base material joint.
　また、レーザ溶接によって、母材接合部の一部と電極母材の一部とを溶融し、凝固させることにより、放電チップを電極母材に接合するため、特に母材接合部の外形を、放電部の側面と電極母材の表面とに沿うような形状にしやすい。それゆえ、容易に、放電部の側面と電極母材の表面とが滑らかに繋がるように放電チップを電極母材に接合することができる。 Further, by melting and solidifying a part of the base material joint part and a part of the electrode base material by laser welding, in order to join the discharge chip to the electrode base material, in particular, the outer shape of the base material joint part, It is easy to make the shape along the side surface of the discharge part and the surface of the electrode base material. Therefore, the discharge chip can be easily joined to the electrode base material so that the side surface of the discharge part and the surface of the electrode base material are smoothly connected.
　以上のごとく、本発明によれば、母材接合部への飛び火を抑制することができる内燃機関用のスパークプラグの製造方法を提供することができる。 As described above, according to the present invention, it is possible to provide a method of manufacturing a spark plug for an internal combustion engine that can suppress a spark to the base material joint.
実施例１における、スパークプラグの先端部の側面図。The side view of the front-end | tip part of the spark plug in Example 1. FIG. 実施例１における、チップ作製工程によって得られる放電チップの（ａ）正面図、（ｂ）平面図。The (a) front view and (b) top view of the discharge chip obtained by the chip | tip preparation process in Example 1. FIG. 実施例１における、仮接合工程によって電極母材に放電チップを仮接合した状態を示す正面図。The front view which shows the state which carried out the temporary joining of the discharge chip to the electrode base material by the temporary joining process in Example 1. FIG. 実施例１における、本接合工程によって電極母材に放電チップを溶接した状態を示す正面図。The front view which shows the state which welded the discharge tip to the electrode base material by the main joining process in Example 1. FIG. 実施例１における、レーザ溶接の様子を説明する断面説明図。Sectional explanatory drawing explaining the mode of the laser welding in Example 1. FIG. 実施例１における、本接合工程によって電極母材に放電チップを溶接した状態を示す断面説明図。Sectional explanatory drawing which shows the state which welded the discharge tip to the electrode base material by the main joining process in Example 1. FIG. 実施例２における、スパークプラグの先端部の側面図。The side view of the front-end | tip part of the spark plug in Example 2. FIG. 実施例２における、レーザ溶接の様子を説明する断面説明図。Sectional explanatory drawing explaining the mode of the laser welding in Example 2. FIG. 実施例２における、本接合工程によって電極母材に放電チップを溶接した状態を示す断面説明図。Sectional explanatory drawing which shows the state which welded the discharge tip to the electrode base material by the main joining process in Example 2. FIG.
　上記内燃機関用のスパークプラグにおいて、中心電極が上記放電チップを備えていてもよいし、接地電極が上記放電チップを備えていてもよいし、中心電極と接地電極との双方が上記放電チップを備えていてもよい。
　上記スパークプラグは、例えば、自動車エンジン等の内燃機関の燃焼室内における点火手段として用いることができる。 In the spark plug for the internal combustion engine, the center electrode may include the discharge tip, the ground electrode may include the discharge tip, or both the center electrode and the ground electrode may include the discharge tip. You may have.
The spark plug can be used as ignition means in a combustion chamber of an internal combustion engine such as an automobile engine.
　また、上記チップ作製工程において得られる上記放電チップは、上記母材接合部の直径が上記放電部の直径よりも大きいものとすることができる。この場合には、上記チップ作製工程において、放電部と母材接合部との接合を安定して行いやすい。ところが、母材接合部の直径が放電部の直径よりも大きい場合、両者の間には段差が生じ、母材接合部の尖った角部が現れることとなる。この尖った角部が現れたままの状態で放電チップが電極母材に接合されると、スパークプラグの放電火花が母材接合部に飛び火しやすくなる。そこで、上述のごとく、上記本接合工程において、放電部の側面と電極母材の表面とが尖ったエッジを有しない連結面により滑らかに連結されるように放電チップを電極母材に接合することによって、母材接合部の尖った角部を取ることができる。これにより、母材接合部への飛び火を効果的に抑制することができる。 Further, the discharge chip obtained in the chip manufacturing process may have a diameter of the base material joint portion larger than a diameter of the discharge portion. In this case, it is easy to stably join the discharge portion and the base material joint portion in the chip manufacturing process. However, when the diameter of the base material joint is larger than the diameter of the discharge part, a step is generated between the two, and a sharp corner of the base material joint appears. If the discharge tip is bonded to the electrode base material with the sharp corners still appearing, the sparks of the spark plug are likely to fly to the base material bonding portion. Therefore, as described above, in the main joining step, the discharge chip and the electrode base material are joined to the electrode base material so that the side surface of the discharge portion and the surface of the electrode base material are smoothly connected by a connection surface having no sharp edge. Thus, it is possible to take a sharp corner of the base material joint. Thereby, the spark to the base material junction part can be suppressed effectively.
（実施例１）
　上記内燃機関用のスパークプラグの製造方法にかかる実施例につき、図１～図６を用いて説明する。
　本例の製造方法によって得られるスパークプラグ１は、図１に示すごとく、互いの間に火花放電ギャップ１１を形成して対向配置された中心電極２と接地電極３とが、火花放電ギャップ１１に向かって突出するように電極母材２０、３０に接合された放電チップ４、５をそれぞれ備えている。 (Example 1)
Examples of the method for manufacturing a spark plug for the internal combustion engine will be described with reference to FIGS.
As shown in FIG. 1, the spark plug 1 obtained by the manufacturing method of this example has a spark discharge gap 11 in which a center electrode 2 and a ground electrode 3 that are opposed to each other with a spark discharge gap 11 formed therebetween. Discharge chips 4 and 5 joined to the electrode base materials 20 and 30 so as to protrude toward the surface, respectively.
　本例においては、接地電極３における放電チップ５が、火花放電ギャップ１１側に配された放電部５１と、放電部５１よりも融点の低い材料からなると共に電極母材３０と接合される母材接合部５２とを、互いに接合してなる。一方、中心電極２における放電チップ４は、複合部材ではない。 In this example, the discharge tip 5 in the ground electrode 3 is made of a discharge part 51 disposed on the spark discharge gap 11 side, and a base material joined to the electrode base material 30 while being made of a material having a melting point lower than that of the discharge part 51. The joining portion 52 is joined to each other. On the other hand, the discharge tip 4 in the center electrode 2 is not a composite member.
　本例のスパークプラグ１の製造方法は、以下に示す、チップ作製工程と、仮接合工程と、本接合工程とを有する。すなわち、以下の工程を経ることにより、電極母材３０に放電チップ５を接合してなる接地電極３を形成する。
　チップ作製工程においては、図２に示すごとく、放電部５１と母材接合部５２とを互いに接合して、放電チップ５を作製する。仮接合工程においては、抵抗溶接によって、図３に示すごとく、放電チップ５を母材接合部５２において電極母材３０に仮接合する。本接合工程においては、レーザ溶接によって、図４に示すごとく、母材接合部５２の一部と電極母材３０の一部とを溶融し、凝固させることにより、放電部５１の側面５１１と電極母材３０の表面とが尖ったエッジを有しない連結面５２３により滑らかに連結されるように放電チップ５を電極母材３０に接合する。 The manufacturing method of the spark plug 1 of this example includes a chip manufacturing process, a temporary bonding process, and a main bonding process described below. That is, the ground electrode 3 formed by joining the discharge chip 5 to the electrode base material 30 is formed through the following steps.
In the chip manufacturing process, as shown in FIG. 2, the discharge part 5 and the base material bonding part 52 are bonded together to manufacture the discharge chip 5. In the temporary joining step, the discharge chip 5 is temporarily joined to the electrode base material 30 at the base material joint portion 52 by resistance welding as shown in FIG. In the main joining step, as shown in FIG. 4, by melting and solidifying a part of the base material joining part 52 and a part of the electrode base material 30 by laser welding, the side surface 511 and the electrode of the discharge part 51 are solidified. The discharge chip 5 is joined to the electrode base material 30 so that the surface of the base material 30 is smoothly connected to the connection surface 523 having no sharp edge.
　図１に示すごとく、接地電極３の電極母材３０は、スパークプラグ１のハウジング１２の先端から先端側（図１の下側）へ延びると共に中心軸側へ屈曲している。中心電極２の電極母材２０は、ハウジング１２の内側に保持された絶縁碍子１３の内側に保持されている。ハウジング１２及び接地電極３の電極母材３０は、いずれもニッケル合金からなる。また、中心電極２の電極母材２０もニッケル合金からなる。 As shown in FIG. 1, the electrode base material 30 of the ground electrode 3 extends from the distal end of the housing 12 of the spark plug 1 to the distal end side (lower side in FIG. 1) and is bent toward the central axis. The electrode base material 20 of the center electrode 2 is held inside the insulator 13 held inside the housing 12. Both the housing 12 and the electrode base material 30 of the ground electrode 3 are made of a nickel alloy. The electrode base material 20 of the center electrode 2 is also made of a nickel alloy.
　そして、接地電極３の電極母材３０は、スパークプラグ１の軸方向（以下において、簡単に「プラグ軸方向」という。）において中心電極２と対向する対向面３１を備え、該対向面３１に、放電チップ５が接合されている。また、プラグ軸方向において対向面３１に対向する、中心電極２の電極母材２０の先端に、放電チップ４が接合されている。本例において、中心電極２の放電チップ４は、複合部材ではなく、例えば、イリジウム合金等の貴金属チップからなる。すなわち、貴金属からなる放電チップ４が、中心電極２の電極母材２０の先端に溶接等によって接合されている。 The electrode base material 30 of the ground electrode 3 includes a facing surface 31 that faces the center electrode 2 in the axial direction of the spark plug 1 (hereinafter simply referred to as “plug axial direction”). The discharge chip 5 is joined. In addition, the discharge chip 4 is joined to the tip of the electrode base material 20 of the center electrode 2 facing the facing surface 31 in the plug axis direction. In this example, the discharge tip 4 of the center electrode 2 is not a composite member but is made of a noble metal tip such as an iridium alloy. That is, the discharge tip 4 made of a noble metal is joined to the tip of the electrode base material 20 of the center electrode 2 by welding or the like.
　一方、接地電極３の放電チップ５は、上述のごとく、放電部５１と母材接合部５２とを互いに接合した複合部材からなる。この複合部材からなる放電チップ５を備えた接地電極３を形成するにあたって、上記のチップ作製工程と、仮接合工程と、本接合工程とを行う。各工程の一例につき、以下に具体的に説明する。 On the other hand, the discharge chip 5 of the ground electrode 3 is composed of a composite member in which the discharge part 51 and the base material joining part 52 are joined to each other as described above. In forming the ground electrode 3 including the discharge chip 5 made of the composite member, the above-described chip manufacturing process, provisional bonding process, and main bonding process are performed. An example of each process will be specifically described below.
　チップ作製工程においては、まず、比較的高融点（例えば、融点１７００℃以上）の材料からなる放電部５１と、放電部５１よりも低融点の材料からなる母材接合部５２を用意する。放電部５１の材料としては、例えば、Ｐｔ（白金）、Ｉｒ（イリジウム）、Ｒｕ（ルテニウム）、Ｒｈ（ロジウム）、Ｐｄ（パラジウム）、Ｏｓ（オスミウム）等を用いることができる。また、母材接合部５２としては、例えばＮｉ（ニッケル）合金を用いることができる。なお、このＮｉ合金としては、例えば、融点１４００～１４５０℃のものを用いることができる。 In the chip manufacturing process, first, a discharge part 51 made of a material having a relatively high melting point (for example, a melting point of 1700 ° C. or higher) and a base material joining part 52 made of a material having a lower melting point than the discharge part 51 are prepared. As the material of the discharge part 51, for example, Pt (platinum), Ir (iridium), Ru (ruthenium), Rh (rhodium), Pd (palladium), Os (osmium), or the like can be used. Further, as the base material joining portion 52, for example, a Ni (nickel) alloy can be used. As this Ni alloy, for example, one having a melting point of 1400 to 1450 ° C. can be used.
　これらの金属部材を打ち抜き加工等することによって、それぞれ、円柱形状の放電部５１及び母材接合部５２とする。そして、母材接合部５２の直径は、放電部５１の直径よりも大きい。
　このように形成された円柱形状の放電部５１と母材接合部５２とを、図２に示すごとく、両者の中心軸を一致させつつ軸方向に重ね合わせる。そして、両者を互いに押圧した状態で、熱処理を行い、放電部５１と母材接合部５２とを拡散接合によって接合する。これにより、複合部材（Clad Material）としての放電チップ５を得る。それゆえ、放電チップ５における放電部５１と母材接合部５２との界面付近には、放電部５１と母材接合部５２のそれぞれ材料の原子が互いに相手側に拡散した拡散層（図示略）が形成されている。 By punching these metal members, a cylindrical discharge part 51 and a base material joining part 52 are obtained. The diameter of the base material joint 52 is larger than the diameter of the discharge part 51.
As shown in FIG. 2, the cylindrical discharge portion 51 and the base material joint portion 52 formed in this way are overlapped in the axial direction while matching the central axes of both. And in the state which pressed both mutually, heat processing is performed and the discharge part 51 and the base material junction part 52 are joined by diffusion joining. Thereby, the discharge chip 5 as a composite member (Clad Material) is obtained. Therefore, in the vicinity of the interface between the discharge part 51 and the base material bonding part 52 in the discharge chip 5, a diffusion layer (not shown) in which atoms of the respective materials of the discharge part 51 and the base material bonding part 52 diffuse to each other. Is formed.
　上記チップ作製工程において得られる放電チップ５は、母材接合部５２の直径が放電部の直径よりも大きい。それゆえ、この段階においては、母材接合部５２と放電部５１との間には、段差が形成されており、この段差部分に母材接合部５２の尖った角部５２１が存在する。 In the discharge chip 5 obtained in the above chip manufacturing process, the diameter of the base material joint portion 52 is larger than the diameter of the discharge portion. Therefore, at this stage, a step is formed between the base material joint portion 52 and the discharge portion 51, and a sharp corner 521 of the base material joint portion 52 exists at this step portion.
　チップ作製工程において得られた放電チップ５を、仮接合工程において、図３に示すごとく、電極母材３０の対向面３１に仮接合する。仮接合は、抵抗溶接によって行う。すなわち、電極母材３０の対向面３１における所定の位置に、放電チップ５を母材接合部５２側の面において当接させる。そして、放電チップ５と電極母材３０を一対の抵抗溶接の電極の間で挟持しつつ、放電チップ５と電極母材３０との間に電流を流す。これにより、ジュール熱によって放電チップ５を電極母材３０に溶接して、仮接合する。 In the temporary bonding step, the discharge chip 5 obtained in the chip manufacturing step is temporarily bonded to the facing surface 31 of the electrode base material 30 as shown in FIG. Temporary joining is performed by resistance welding. That is, the discharge chip 5 is brought into contact with a predetermined position on the facing surface 31 of the electrode base material 30 on the surface on the base material joint portion 52 side. A current is passed between the discharge tip 5 and the electrode base material 30 while the discharge tip 5 and the electrode base material 30 are sandwiched between the pair of resistance welding electrodes. Thereby, the discharge tip 5 is welded to the electrode base material 30 by Joule heat and temporarily joined.
　次いで、本接合工程において、レーザ溶接によって、図４に示すごとく、放電チップ５を電極母材３０に接合する。すなわち、図５に示すごとく、電極母材３０に仮接合された放電チップ５に対して、その接合部の周囲から、レーザ光Ｌを照射する。ここで、レーザ光Ｌは、電極母材３０に対する接合部の全周にわたる複数箇所から照射する。また、放電部５１の融点よりも低い温度にてレーザ溶接を行う。すなわち、本接合工程においては、放電部５１を溶融させず、母材接合部５２の一部と電極母材３０の一部とを溶融させる。これにより、図６に示すごとく、母材接合部５２の外周部に、母材接合部５２と電極母材３０とが溶け合って凝固した溶融部５２２が環状に形成される。 Next, in the main joining step, the discharge tip 5 is joined to the electrode base material 30 by laser welding as shown in FIG. That is, as shown in FIG. 5, the laser light L is irradiated from the periphery of the joined portion to the discharge chip 5 temporarily joined to the electrode base material 30. Here, the laser light L is irradiated from a plurality of locations over the entire circumference of the joint portion with respect to the electrode base material 30. Further, laser welding is performed at a temperature lower than the melting point of the discharge part 51. That is, in the main joining step, the discharge part 51 is not melted, and a part of the base material joint part 52 and a part of the electrode base material 30 are melted. As a result, as shown in FIG. 6, a molten portion 522 in which the base material joint 52 and the electrode base material 30 are melted and solidified is formed in an annular shape on the outer periphery of the base material joint 52.
　また、このレーザ溶接によって、母材接合部５２の尖った角部５２１（図３、図５）が、図４、図６に示すごとく、形状的に除去されて、放電部５１の側面５１１と電極母材３０の表面（対向面３１）とを滑らかに連結する連結面５２３が形成される。この連結面５２３は、放電チップ５の中心軸を通る平面による断面の形状が、曲線と直線とを滑らかに繋ぐような形状となっており、尖ったエッジを有しない。 Further, by this laser welding, the sharp corners 521 (FIGS. 3 and 5) of the base material joint portion 52 are removed in shape as shown in FIGS. 4 and 6, and the side surface 511 of the discharge portion 51 is removed. A connection surface 523 that smoothly connects the surface of the electrode base material 30 (opposing surface 31) is formed. The connection surface 523 has a shape in which a cross section of a plane passing through the central axis of the discharge chip 5 smoothly connects a curve and a straight line, and does not have a sharp edge.
　次に、本例の作用効果につき説明する。
　上記本接合工程においては、レーザ溶接によって、母材接合部５２の一部と電極母材３０の一部とを溶融し、凝固させることにより、放電チップ５を電極母材３０に接合する。これにより、放電部５１の側面５１１と電極母材３０の対向面３１とが尖ったエッジを有しない連結面５２３により連結されるように放電チップ５を電極母材３０に接合する。それゆえ、得られるスパークプラグ１において、放電チップ５の側部に母材接合部５２の尖った角部５２１（図３）が現れることもなく、電界強度が局部的に高くなる部位が母材接合部５２に形成されることを防ぐことができる。その結果、母材接合部５２への飛び火を抑制することができる。 Next, the function and effect of this example will be described.
In the main joining step, the discharge chip 5 is joined to the electrode base material 30 by melting and solidifying a part of the base material joint portion 52 and a part of the electrode base material 30 by laser welding. Thereby, the discharge chip 5 is joined to the electrode base material 30 so that the side surface 511 of the discharge part 51 and the opposing surface 31 of the electrode base material 30 are connected by the connection surface 523 having no sharp edge. Therefore, in the spark plug 1 obtained, the sharpened corners 521 (FIG. 3) of the base material joint 52 do not appear on the side of the discharge chip 5, and the region where the electric field strength is locally increased is the base material. It is possible to prevent the joint portion 52 from being formed. As a result, sparks to the base material joint 52 can be suppressed.
　また、上記のように、レーザ溶接によって、母材接合部５２の一部と電極母材３０の一部とを溶融し、凝固させることにより、放電チップ５を電極母材３０に接合するため、特に母材接合部５２の外形を、図４に示すごとく、放電部５１の側面５１１と電極母材３０の対向面３１とに沿うような形状にしやすい。それゆえ、容易に、放電部５１の側面５１１と電極母材３０の対向面３１とが尖ったエッジを有しない連結面５２３により連結されるように放電チップ５を電極母材３０に接合することができる。 Moreover, in order to join the discharge tip 5 to the electrode base material 30 by melting and solidifying a part of the base material joint portion 52 and a part of the electrode base material 30 by laser welding as described above, In particular, as shown in FIG. 4, the outer shape of the base material bonding portion 52 can be easily formed along the side surface 511 of the discharge portion 51 and the facing surface 31 of the electrode base material 30. Therefore, the discharge chip 5 is easily joined to the electrode base material 30 so that the side surface 511 of the discharge part 51 and the facing surface 31 of the electrode base material 30 are connected by the connection surface 523 having no sharp edge. Can do.
　また、チップ作製工程において得られる放電チップ５（図２）は、母材接合部５２の直径が放電部５１の直径よりも大きい。これにより、放電部５１と母材接合部５２との接合を安定して行いやすい。すなわち、放電部５１の端面の全面を母材接合部５２に容易に当接させることができるため、母材接合部５２に対する接合面積を一定とすることが容易となり、接合強度を安定して得ることができる。ところが、母材接合部５２の直径が放電部５１の直径よりも大きい場合、両者の間には段差が生じ、母材接合部５２の尖った角部５２１が現れることとなる。この尖った角部５２１が現れたままの状態で放電チップ５が電極母材３０に接合されると、スパークプラグ１の放電火花が母材接合部５２に飛び火しやすくなる。そこで、上述のごとく、本接合工程において、放電部５１の側面５１１と電極母材３０の対向面３１とが尖ったエッジを有しない連結面５２３により連結されるように放電チップ５を電極母材３０に接合することによって、図４に示すごとく、母材接合部５２の尖った角部５２１を取ることができる。これにより、放電チップ５の側面を放電部５１の側面５１１から電極母材３０の表面（対向面３１）にかけて、尖ったエッジを有しない連結面５２３により滑らかに連結することができる。その結果、母材接合部５２への飛び火を効果的に抑制することができる。 Further, in the discharge chip 5 (FIG. 2) obtained in the chip manufacturing process, the diameter of the base material joint portion 52 is larger than the diameter of the discharge portion 51. Thereby, it is easy to stably join the discharge part 51 and the base material joining part 52. That is, since the entire end face of the discharge part 51 can be easily brought into contact with the base material joining part 52, the joining area with respect to the base material joining part 52 can be easily made constant, and the joining strength can be obtained stably. be able to. However, when the diameter of the base material joint portion 52 is larger than the diameter of the discharge portion 51, a step is generated between them, and a sharp corner portion 521 of the base material joint portion 52 appears. When the discharge tip 5 is joined to the electrode base material 30 with the sharp corners 521 appearing, the discharge spark of the spark plug 1 is likely to fly to the base material joint 52. Therefore, as described above, in the main joining step, the discharge chip 5 is connected to the electrode base material so that the side surface 511 of the discharge part 51 and the facing surface 31 of the electrode base material 30 are connected by the connection surface 523 having no sharp edge. By bonding to 30, as shown in FIG. 4, the sharp corner 521 of the base material bonding portion 52 can be taken. Thereby, the side surface of the discharge chip 5 can be smoothly connected to the surface (opposite surface 31) of the electrode base material 30 from the side surface 511 of the discharge part 51 by the connection surface 523 which does not have a sharp edge. As a result, it is possible to effectively suppress the sparks to the base material joint 52.
　また、本接合工程においては、放電部５１の融点よりも低い温度にてレーザ溶接を行う。これにより、高融点材料からなる放電部５１の体積及び形状を、充分に確保して、スパークプラグ１の耐消耗性を確保することができる。 Further, in this joining process, laser welding is performed at a temperature lower than the melting point of the discharge part 51. Thereby, the volume and shape of the discharge part 51 made of a high melting point material can be sufficiently ensured, and the wear resistance of the spark plug 1 can be ensured.
　以上のごとく、本例によれば、母材接合部への飛び火を抑制することができる内燃機関用のスパークプラグの製造方法を提供することができる。 As described above, according to this example, it is possible to provide a method for manufacturing a spark plug for an internal combustion engine that can suppress a spark to the base metal joint.
（実施例２）
　本例は、図７～図９に示すごとく、中心電極２の放電チップ４も、火花放電ギャップ１１側に配された放電部４１と、放電部４１よりも融点の低い材料からなると共に電極母材２０と接合される母材接合部４２とを、互いに接合してなる複合材によって構成した例である。 (Example 2)
In this example, as shown in FIGS. 7 to 9, the discharge tip 4 of the center electrode 2 is also composed of a discharge part 41 disposed on the spark discharge gap 11 side, a material having a melting point lower than that of the discharge part 41, and an electrode mother. This is an example in which the base material joining portion 42 joined to the material 20 is composed of a composite material formed by joining together.
　そして、中心電極２を形成する際にも、実施例１において説明した、チップ作製工程と、仮接合工程と、本接合工程とを行う。
　チップ作製工程は、実施例１のチップ作製工程と同様に、放電部４１と母材接合部４２とを拡散接合して、放電チップ４を得る。次いで、仮接合工程において、放電チップ４を、図８に示すごとく、中心電極２の電極母材２０の先端面２１に、抵抗溶接によって仮接合する。すなわち、放電チップ４を接合する前の中心電極２の電極母材２０の先端部分は、略円錐形状となっていると共にその先端が軸方向に直交する平坦面を有する。この平坦面である先端面２１に、母材接合部４２側を当接させるようにして放電チップ４を仮接合する。 And also when forming the center electrode 2, the chip | tip preparation process demonstrated in Example 1, the temporary joining process, and the main joining process are performed.
In the chip manufacturing process, similarly to the chip manufacturing process of the first embodiment, the discharge part 41 and the base material bonding part 42 are diffusion-bonded to obtain the discharge chip 4. Next, in the temporary joining step, the discharge chip 4 is temporarily joined by resistance welding to the tip surface 21 of the electrode base material 20 of the center electrode 2 as shown in FIG. That is, the tip portion of the electrode base material 20 of the center electrode 2 before joining the discharge chip 4 has a substantially conical shape and has a flat surface whose tip is orthogonal to the axial direction. The discharge chip 4 is temporarily bonded to the tip surface 21 which is a flat surface so that the base material bonding portion 42 side is brought into contact therewith.
　次いで、本接合工程において、レーザ溶接によって、放電チップ４を電極母材２０に接合する。このとき、放電チップ４の母材接合部４２と電極母材２０との溶融部４２２が環状に形成される。そして、母材接合部４２の尖った角部４２１（図８）が、図９に示すごとく、形状的に除去されて、放電部４１の側面４１１と電極母材２０の表面（略円錐状部分の側面２２）とを滑らかに連結する連結面４２３が形成される。この連結面４２３は、放電チップ５の中心軸を通る平面による断面の形状が、曲線と直線とを滑らかに繋ぐような形状となっており、尖ったエッジを有しない。 Next, in the main joining step, the discharge tip 4 is joined to the electrode base material 20 by laser welding. At this time, a melting portion 422 between the base material joint portion 42 of the discharge chip 4 and the electrode base material 20 is formed in an annular shape. And the sharp corner | angular part 421 (FIG. 8) of the base material junction part 42 is removed geometrically as shown in FIG. 9, and the side surface 411 of the discharge part 41 and the surface (substantially conical part) of the electrode base material 20 are removed. The connecting surface 423 is formed to smoothly connect the side surface 22). The connection surface 423 has a shape in which a cross section of a plane passing through the central axis of the discharge chip 5 smoothly connects a curve and a straight line, and does not have a sharp edge.
　その他は、実施例１と同様である。なお、本例又は本例に関する図面において用いた符号のうち、実施例１において用いた符号と同一のものは、特に示さない限り、実施例１と同様の構成要素等を表す。 Others are the same as in Example 1. Of the reference numerals used in this example or the drawings relating to this example, the same reference numerals as those used in the first embodiment denote the same components as in the first embodiment unless otherwise specified.
　本例の場合には、中心電極２側においても、放電火花が電極母材２０へ飛び火することを抑制することができる。その結果、中心電極２と接地電極３との放電部４１、５１同士の間において、より確実に正常な放電火花を生じさせることができる。
　その他、実施例１と同様の作用効果を有する。 In the case of this example, it is possible to suppress the discharge spark from flying to the electrode base material 20 also on the center electrode 2 side. As a result, a normal discharge spark can be more reliably generated between the discharge portions 41 and 51 of the center electrode 2 and the ground electrode 3.
In addition, the same effects as those of the first embodiment are obtained.
　なお、上記実施例以外にも、例えば、中心電極を実施例２と同様の構成としつつ、接地電極の放電チップを複合材ではない金属チップによって構成したり、接地電極に放電チップを設けない構成とたりすることもできる。 In addition to the above embodiment, for example, the center electrode has the same configuration as that of the second embodiment, and the discharge tip of the ground electrode is made of a metal tip that is not a composite material, or the discharge tip is not provided on the ground electrode. You can also.
　１　スパークプラグ
　１１　火花放電ギャップ
　２　中心電極
　２０　（中心電極の）電極母材
　３　接地電極
　３０　（接地電極の）電極母材
　４　（中心電極の）放電チップ
　４１　（中心電極の）放電部
　４２　（中心電極の）母材接合部
　５　（接地電極の）放電チップ
　５１　（接地電極の）放電部
　５２　（接地電極の）母材接合部 DESCRIPTION OF SYMBOLS 1 Spark plug 11 Spark discharge gap 2 Center electrode 20 (base electrode) electrode base material 3 Ground electrode 30 (ground electrode) electrode base material 4 (center electrode) discharge tip 41 (center electrode) discharge part 42 (center) Electrode base material joint 5 Discharge tip 51 (ground electrode) Discharge part 52 (ground electrode) Base material joint (ground electrode)

Claims (3)

  1. 　互いの間に火花放電ギャップ（１１）を形成して対向配置された中心電極（２）と接地電極（３）との少なくとも一方が、上記火花放電ギャップ（１１）に向かって突出するように電極母材（２０、３０）に接合された放電チップ（４、５）を備えている、内燃機関用のスパークプラグ（１）を製造する方法であって、
    　上記火花放電ギャップ（１１）側に配される放電部（４１、５１）と、該放電部（４１、５１）よりも融点の低い材料からなると共に上記電極母材（２０、３０）と接合される母材接合部（４２、５２）とを、互いに接合して上記放電チップ（４、５）を作製するチップ作製工程と、
    　抵抗溶接によって、上記放電チップ（４、５）を上記母材接合部（４２、５２）において上記電極母材（２０、３０）に仮接合する仮接合工程と、
    　レーザ溶接によって、上記放電部（４１、５１）の側面（４１１、５１１）と上記電極母材（２０、３０）の表面（２２、３１）とが尖ったエッジを有しない連結面（４２３、５２３）により滑らかに連結されるように上記放電チップ（４、５）を上記電極母材（２０、３０）に接合する本接合工程とを有することを特徴とする内燃機関用のスパークプラグ（１）の製造方法。     An electrode is formed such that at least one of the center electrode (2) and the ground electrode (3) arranged opposite each other with a spark discharge gap (11) formed therebetween protrudes toward the spark discharge gap (11). A method for producing a spark plug (1) for an internal combustion engine comprising a discharge tip (4, 5) joined to a base material (20, 30),
    The discharge part (41, 51) disposed on the spark discharge gap (11) side is made of a material having a melting point lower than that of the discharge part (41, 51) and is joined to the electrode base material (20, 30). Chip manufacturing step of manufacturing the discharge chip (4, 5) by bonding the base material bonding parts (42, 52) to each other;
    A temporary joining step of temporarily joining the discharge tip (4, 5) to the electrode base material (20, 30) at the base material joint (42, 52) by resistance welding;
    Connecting surfaces (423, 523) having no sharp edges between the side surfaces (411, 511) of the discharge parts (41, 51) and the surfaces (22, 31) of the electrode base materials (20, 30) by laser welding. A spark plug (1) for an internal combustion engine, comprising: a main joining step for joining the discharge tip (4, 5) to the electrode base material (20, 30) so as to be smoothly connected to each other. Manufacturing method.
  2. 　上記チップ作製工程において得られる上記放電チップ（４、５）は、上記母材接合部（４２、５２）の直径が上記放電部（４１、５１）の直径よりも大きいことを特徴とする請求項１に記載の内燃機関用のスパークプラグ（１）の製造方法。 The discharge chip (4, 5) obtained in the chip manufacturing step is characterized in that a diameter of the base material joining portion (42, 52) is larger than a diameter of the discharge portion (41, 51). A method for producing a spark plug (1) for an internal combustion engine according to claim 1.
  3. 　上記本接合工程においては、上記放電部（４１、５１）の融点よりも低い温度にてレーザ溶接を行うことを特徴とする請求項１又は２に記載の内燃機関用のスパークプラグ（１）の製造方法。 The spark plug (1) for an internal combustion engine according to claim 1 or 2, wherein in the main joining step, laser welding is performed at a temperature lower than the melting point of the discharge part (41, 51). Production method.
PCT/JP2014/063507 2013-05-21 2014-05-21 Method for manufacturing spark plug for internal combustion engine WO2014189088A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105807589A (en) * 2015-01-16 2016-07-27 富士施乐株式会社 Tubular body, tubular body unit, image forming apparatus, and method for manufacturing tubular body

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6702094B2 (en) 2016-08-31 2020-05-27 株式会社デンソー Spark plug
JP6944429B2 (en) * 2018-11-09 2021-10-06 日本特殊陶業株式会社 Spark plug

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008077838A (en) * 2006-09-18 2008-04-03 Denso Corp Spark plug for internal combustion engine, and manufacturing method therefor
JP2009533803A (en) * 2006-04-07 2009-09-17 フェデラル−モーグル コーポレイション Spark plug
WO2013015262A1 (en) 2011-07-28 2013-01-31 田中貴金属工業株式会社 Clad electrode for spark plug and method for manufacturing same

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101536277B (en) * 2005-11-18 2012-02-29 费德罗-莫格尔公司 Spark plug with multi-layer firing tip
JP4964896B2 (en) * 2005-11-18 2012-07-04 フェデラル−モーグル コーポレイション Spark plug with multilayer ignition tip
CN101670488A (en) * 2009-02-05 2010-03-17 株洲湘火炬火花塞有限责任公司 Laser welding method of noble metal spark plug electrode

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009533803A (en) * 2006-04-07 2009-09-17 フェデラル−モーグル コーポレイション Spark plug
JP2008077838A (en) * 2006-09-18 2008-04-03 Denso Corp Spark plug for internal combustion engine, and manufacturing method therefor
WO2013015262A1 (en) 2011-07-28 2013-01-31 田中貴金属工業株式会社 Clad electrode for spark plug and method for manufacturing same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105807589A (en) * 2015-01-16 2016-07-27 富士施乐株式会社 Tubular body, tubular body unit, image forming apparatus, and method for manufacturing tubular body
CN105807589B (en) * 2015-01-16 2018-12-18 富士施乐株式会社 The manufacturing method of tubular body, tubulose body unit, image forming apparatus and tubular body

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