JP6910992B2

JP6910992B2 - Igniter plug

Info

Publication number: JP6910992B2
Application number: JP2018126405A
Authority: JP
Inventors: 鈴木　俊太郎; 俊太郎鈴木; 坂倉　靖; 靖坂倉; 征信長谷川; 文悟内藤; 孝幸大野
Original assignee: NGK Spark Plug Co Ltd
Current assignee: Niterra Co Ltd
Priority date: 2018-07-02
Filing date: 2018-07-02
Publication date: 2021-07-28
Anticipated expiration: 2038-07-02
Also published as: JP2020009530A

Description

本明細書は、イグナイタプラグに関する。 This specification relates to spark plugs.

イグナイタプラグは、ガスタービンエンジン等にて、燃料ガスへの着火のために用いられる。イグナイタプラグは、例えば、中心電極と、中心電極を内部に収容する絶縁体と、絶縁体を内部に収容する主体金具と、主体金具の先端に設けられ、中心電極との間に放電のための間隙を形成する接地電極と、を備えている。 The igniter plug is used for ignition of fuel gas in a gas turbine engine or the like. The igniter plug is provided, for example, between the center electrode, the insulator that houses the center electrode inside, the main metal fitting that houses the insulator inside, and the tip of the main metal fitting, and is used for discharging between the center electrode and the center electrode. It is provided with a ground electrode that forms a gap.

このようなイグナイタプラグでは、電源と接続されたコネクタを介して中心電極に駆動電圧が印加される。例えば、特許文献１のイグナイタプラグは、コネクタが接触するための端子を備えており、該端子に設けられた孔に中心電極の後端部が挿通される。該端子は、ネジによって絶縁体に固定され、端子と中心電極の後端部との隙間には、導電性ガラスを基材とする導電性シールが充填されている。これによって、端子と中心電極間の導電性が向上できる、とされている。 In such an igniter plug, a drive voltage is applied to the center electrode via a connector connected to a power supply. For example, the igniter plug of Patent Document 1 is provided with a terminal for contacting the connector, and the rear end portion of the center electrode is inserted into a hole provided in the terminal. The terminal is fixed to an insulator with a screw, and the gap between the terminal and the rear end of the center electrode is filled with a conductive seal made of conductive glass as a base material. It is said that this can improve the conductivity between the terminal and the center electrode.

特開２０１３−２１８９８１号公報Japanese Unexamined Patent Publication No. 2013-21881

しかしながら、上記技術では、絶縁体に固定された端子に対して中心電極の後端部が導電性シールによって固定されるために、絶縁体が端子および中心電極の後端部を保持する形態となる。上記技術では、中心電極の先端部も絶縁体に保持されているため、中心電極が熱膨張によって伸長した際に中心電極が湾曲する可能性があった。該湾曲によって中心電極が主体金具に近づきフラッシュオーバが発生するおそれがある。なお、フラッシュオーバは、放電のための間隙とは異なる部分で、中心電極と主体金具との間に放電が発生する現象である。仮に、導電性シールを廃止する等によって、中心電極を絶縁体や端子に保持せずに端子に対して中心電極が軸線方向に移動可能とすれば、中心電極が湾曲することを抑制でき、主体金具の内部でフラッシュオーバが発生することを抑制できる。しかしながら、この場合には、端子と中心電極との間の導電性、ひいては、コネクタと中心電極との間の導電性が低下する可能性があった。 However, in the above technique, since the rear end portion of the center electrode is fixed to the terminal fixed to the insulator by the conductive seal, the insulator holds the terminal and the rear end portion of the center electrode. .. In the above technique, since the tip of the center electrode is also held by the insulator, there is a possibility that the center electrode may be curved when the center electrode is extended by thermal expansion. Due to the curvature, the center electrode may approach the main metal fitting and flashover may occur. Note that flashover is a phenomenon in which discharge occurs between the center electrode and the main metal fitting at a portion different from the gap for discharge. If the center electrode can be moved in the axial direction with respect to the terminal without holding the center electrode in the insulator or the terminal by abolishing the conductive seal, the bending of the center electrode can be suppressed and the main body can be suppressed. It is possible to suppress the occurrence of flashover inside the metal fittings. However, in this case, the conductivity between the terminal and the center electrode, and by extension, the conductivity between the connector and the center electrode may decrease.

本明細書は、イグナイタプラグにおいて、コネクタと中心電極との間の導電性の向上と、熱膨張時の中心電極の湾曲の抑制と、を両立できる技術を開示する。 The present specification discloses a technique for improving the conductivity between the connector and the center electrode and suppressing the curvature of the center electrode during thermal expansion in the igniter plug.

本明細書に開示される技術は、以下の適用例として実現することが可能である。 The techniques disclosed herein can be realized as the following application examples.

［適用例１］軸線に沿って延び先端側に発火部を有する棒状の中心電極と、
前記軸線に沿って延び前記中心電極が挿通される筒状の絶縁体と、
前記絶縁体の外周に配置され前記絶縁体が固定される主体金具と、
を備え、
前記絶縁体は、先端側絶縁体と、前記先端側絶縁体よりも後端側に位置し前記先端側絶縁体と軸線方向に離間した後端側絶縁体と、を有するイグナイタプラグであって、
前記後端側絶縁体の後端部には、前記中心電極と電源とを電気的に接続するコネクタを内部に収容するためのコネクタ収容部であり、後端側に向かって開放しつつ前記後端側絶縁体の先端部の軸孔よりも拡径された軸孔を有するコネクタ収容部を有し、
前記中心電極は、前記先端側絶縁体の先端部から前記後端側絶縁体の後端部まで延びており、前記中心電極の後端部に前記コネクタと直接接触するコネクタ接触部を有し、
前記中心電極は、前記先端側絶縁体に支持されつつ、前記後端側絶縁体に遊嵌状に挿通され、
前記コネクタ接触部は、前記コネクタ収容部の内部に配置されていることを特徴とするイグナイタプラグ。 [Application Example 1] A rod-shaped center electrode extending along the axis and having an ignition portion on the tip side,
A tubular insulator that extends along the axis and is inserted with the center electrode.
A main metal fitting arranged on the outer periphery of the insulator and to which the insulator is fixed,
With
The insulator is an igniter plug having a tip-side insulator and a rear-end side insulator located on the rear end side of the tip-side insulator and separated from the tip-side insulator in the axial direction.
The rear end portion of the rear end side insulator is a connector accommodating portion for internally accommodating a connector for electrically connecting the center electrode and the power supply, and the rear end portion is opened toward the rear end side. It has a connector accommodating portion having a shaft hole whose diameter is larger than that of the shaft hole at the tip of the end side insulator.
The center electrode extends from the tip end portion of the front end side insulator to the rear end portion of the rear end side insulator, and has a connector contact portion that directly contacts the connector at the rear end portion of the center electrode.
The center electrode is loosely fitted through the rear end side insulator while being supported by the front end side insulator.
The igniter plug, wherein the connector contact portion is arranged inside the connector accommodating portion.

上記構成によれば、中心電極は、コネクタと直接接触するので、他部材を介してコネクタと接触する場合と比較して、コネクタと中心電極間の抵抗を低減して導電性を向上できる。また、中心電極は、後端側絶縁体に遊嵌状に挿通されるので、中心電極が熱膨張によって伸長した場合に湾曲することを抑制できる。したがって、コネクタと中心電極との間の導電性の向上と、熱膨張時の中心電極の湾曲の抑制と、を両立できる。 According to the above configuration, since the center electrode comes into direct contact with the connector, the resistance between the connector and the center electrode can be reduced and the conductivity can be improved as compared with the case where the center electrode comes into contact with the connector via another member. Further, since the center electrode is loosely inserted into the rear end side insulator, it is possible to prevent the center electrode from bending when it is extended due to thermal expansion. Therefore, it is possible to improve the conductivity between the connector and the center electrode and suppress the curvature of the center electrode during thermal expansion.

［適用例２］適用例１に記載のイグナイタプラグであって、
中心電極は、前記発火部を含む第１部分と、前記第１部分よりも比抵抗が小さな材料で形成され前記第１部分よりも後端側に設けられた第２部分と、を有し、
前記第１部分と前記第２部分とは接合されてなることを特徴とするイグナイタプラグ。 [Application Example 2] The igniter plug according to Application Example 1.
The center electrode has a first portion including the ignition portion and a second portion formed of a material having a specific resistivity smaller than that of the first portion and provided on the rear end side of the first portion.
An igniter plug characterized in that the first portion and the second portion are joined to each other.

上記構成によれば、コネクタと発火部を含む第１部分との間に位置する第２部分の抵抗を低減することができ、導電性をさらに向上できる。 According to the above configuration, the resistance of the second portion located between the connector and the first portion including the ignition portion can be reduced, and the conductivity can be further improved.

［適用例３］適用例１または２に記載のイグナイタプラグであって、さらに、
前記後端側絶縁体の前記軸孔の内部に固定された金属製の筒部材を備え、
前記中心電極は、前記筒部材に遊嵌状に挿通されていることを特徴とするイグナイタプラグ。 [Application Example 3] The igniter plug according to Application Example 1 or 2, further
A metal tubular member fixed inside the shaft hole of the rear end side insulator is provided.
The igniter plug is characterized in that the center electrode is loosely inserted into the tubular member.

中心電極が後端側絶縁体に遊嵌状に挿通されているだけであると、イグナイタプラグに加わる振動等により中心電極が後端側絶縁体に接触して後端側絶縁体にクラックが発生するおそれがある。これに対し、上記構成によれば、筒部材によって中心電極が後端側絶縁体に直接接触することが抑制できるので、後端側絶縁体にクラックが発生することを抑制できる。その上、中心電極は筒部材に遊嵌状に挿通されているため、中心電極が熱膨張によって伸長した場合に湾曲することも抑制できる。 If the center electrode is only loosely inserted into the rear end side insulator, the center electrode comes into contact with the rear end side insulator due to vibration applied to the igniter plug, and cracks occur in the rear end side insulator. There is a risk of On the other hand, according to the above configuration, it is possible to prevent the center electrode from directly contacting the rear end side insulator by the tubular member, so that it is possible to suppress the occurrence of cracks in the rear end side insulator. Moreover, since the center electrode is loosely inserted into the tubular member, it is possible to prevent the center electrode from bending when it is extended due to thermal expansion.

［適用例４］適用例１〜３のいずれかに記載のイグナイタプラグであって、さらに、
前記主体金具の内部で、かつ、前記後端側絶縁体と前記先端側絶縁体との間に少なくとも充填された絶縁粉末を備えることを特徴とするイグナイタプラグ。 [Application Example 4] The igniter plug according to any one of Application Examples 1 to 3, further
An igniter plug comprising an insulating powder that is at least filled inside the main metal fitting and between the rear end side insulator and the front end side insulator.

先端側絶縁体と後端側絶縁体とが軸線方向に離間して配置されているので、主体金具と中心電極とが空間のみを介して配置されると、主体金具の内部でフラッシュオーバが発生するおそれがある。これに対し、上記構成によれば、中心電極と主体金具との間の絶縁性を確保して、主体金具の内部でのフラッシュオーバを抑制できる。 Since the front end side insulator and the rear end side insulator are arranged apart from each other in the axial direction, if the main metal fitting and the center electrode are arranged only through the space, a flashover occurs inside the main metal fitting. There is a risk of On the other hand, according to the above configuration, it is possible to secure the insulating property between the center electrode and the main metal fitting and suppress the flashover inside the main metal fitting.

［適用例５］適用例１〜４のいずれかに記載のイグナイタプラグであって、さらに、
前記後端側絶縁体と前記先端側絶縁体との間の前記軸線方向の範囲の少なくとも一部において、前記中心電極が挿通され、前記中心電極に固定された絶縁性の筒部材を備えることを特徴とするイグナイタプラグ。 [Application Example 5] The igniter plug according to any one of Application Examples 1 to 4, and further.
An insulating tubular member through which the center electrode is inserted and fixed to the center electrode is provided in at least a part of the axial range between the rear end side insulator and the front end side insulator. The characteristic igniter plug.

上記構成によれば、中心電極と主体金具との間の絶縁性をさらに確保して、例えば、先端側絶縁体と後端側絶縁体とが軸線方向に離間している位置において、主体金具の内部でのフラッシュオーバを抑制できる。 According to the above configuration, the insulation between the center electrode and the main metal fitting is further secured, and for example, at a position where the front end side insulator and the rear end side insulator are separated from each other in the axial direction, the main metal fitting Internal flashover can be suppressed.

なお、本明細書に開示される技術は、種々の態様で実現することが可能であり、例えば、イグナイタプラグやイグナイタプラグを用いた点火装置、そのイグナイタプラグを搭載するエンジン等の態様で実現することができる。 The technique disclosed in the present specification can be realized in various aspects, for example, an igniter plug, an ignition device using an igniter plug, an engine equipped with the igniter plug, and the like. be able to.

第１実施形態のイグナイタプラグ１００の概略図である。It is the schematic of the igniter plug 100 of 1st Embodiment. イグナイタプラグ１００の先端側の部分の断面図を拡大した図である。It is an enlarged view of the sectional view of the part on the tip end side of an igniter plug 100. イグナイタプラグ１００の後端側の部分の断面図を拡大した図である。It is an enlarged view of the sectional view of the part on the rear end side of an igniter plug 100. イグナイタプラグ１００の先端を軸線ＡＸに沿って先端側から後端側に向かって見た図である。It is a figure which looked at the tip of the igniter plug 100 from the tip side toward the rear end side along the axis AX. 後端側モジュール６１Ｍの製造の説明図である。It is explanatory drawing of manufacture of a rear end side module 61M. 比較形態のイグナイタプラグ１００Ｘの説明図である。It is explanatory drawing of the igniter plug 100X of the comparative form.

Ａ．第１実施形態
Ａ−１．イグナイタプラグ１００の構成：
図１は、第１実施形態のイグナイタプラグ１００の概略図である。図１では、イグナイタプラグ１００の軸線ＡＸよりも左側部分については、外観図が示され、右側部分については、軸線ＡＸを含む面で切断された断面図が示されている。図２は、イグナイタプラグ１００の先端側の部分の断面図を拡大した図である。図３は、イグナイタプラグ１００の後端側の部分の断面図を拡大した図である。図中の一点破線は、イグナイタプラグ１００の軸線ＡＸを示している。軸線ＡＸと平行な方向を軸線方向とも呼ぶ。軸線ＡＸを中心とし、軸線ＡＸと垂直な面上の円の径方向を、単に「径方向」とも呼び、当該円の周方向を、単に「周方向」とも呼ぶ。図における下方向を先端方向ＦＤと呼び、上方向を後端方向ＢＤとも呼ぶ。図における下側を、イグナイタプラグ１００の先端側と呼び、図における上側をイグナイタプラグ１００の後端側と呼ぶ。 A. First Embodiment A-1. Configuration of igniter plug 100:
FIG. 1 is a schematic view of the igniter plug 100 of the first embodiment. In FIG. 1, an external view is shown for a portion on the left side of the axis AX of the igniter plug 100, and a cross-sectional view cut along a surface including the axis AX is shown on the right side portion. FIG. 2 is an enlarged cross-sectional view of a portion of the igniter plug 100 on the tip end side. FIG. 3 is an enlarged view of a cross-sectional view of a portion on the rear end side of the igniter plug 100. The alternate long and short dash line in the figure indicates the axis AX of the igniter plug 100. The direction parallel to the axis AX is also called the axis direction. The radial direction of the circle on the plane centered on the axis AX and perpendicular to the axis AX is also simply referred to as the "diameter direction", and the circumferential direction of the circle is also simply referred to as the "circumferential direction". The downward direction in the figure is referred to as a front end direction FD, and the upward direction is also referred to as a rear end direction BD. The lower side in the figure is referred to as the front end side of the igniter plug 100, and the upper side in the figure is referred to as the rear end side of the igniter plug 100.

イグナイタプラグ１００は、例えば、航空機用のガスタービンエンジンやバーナー点火器等に用いられる点火装置であり、いわゆるイグナイタプラグである。イグナイタプラグ１００は、後端側絶縁体１０と先端側絶縁体２０とから成る絶縁体１と、中心電極４０と、接地電極５０と、主体金具６０と、金属筒部材７０と、絶縁筒部材８０と、を備えている。 The igniter plug 100 is, for example, an ignition device used for a gas turbine engine for an aircraft, a burner igniter, or the like, and is a so-called igniter plug. The igniter plug 100 includes an insulator 1 composed of a rear end side insulator 10 and a front end side insulator 20, a center electrode 40, a ground electrode 50, a main metal fitting 60, a metal cylinder member 70, and an insulating cylinder member 80. And have.

後端側絶縁体１０、先端側絶縁体２０は、アルミナを始めとする絶縁性のセラミックス材料を焼成して形成され、軸線ＡＸに沿って延びる略円筒状の部材である。後端側絶縁体１０、先端側絶縁体２０には、軸線ＡＸに沿って延びる貫通孔である軸孔１２、２２が形成されている。後端側絶縁体１０は、先端側絶縁体２０よりも後端側に位置し、先端側絶縁体２０と後端側絶縁体１０とは、軸線ＡＸの方向に離間している。 The rear end side insulator 10 and the front end side insulator 20 are substantially cylindrical members formed by firing an insulating ceramic material such as alumina and extending along the axis AX. Shaft holes 12 and 22, which are through holes extending along the axis AX, are formed in the rear end side insulator 10 and the front end side insulator 20. The rear end side insulator 10 is located on the rear end side of the front end side insulator 20, and the front end side insulator 20 and the rear end side insulator 10 are separated from each other in the direction of the axis AX.

後端側絶縁体１０は、後端側の第１部材１３と先端側の第２部材１４とを備えている。第１部材１３と第２部材１４とは、シール部材９ａ、９ｂによって接合されている。図３に示すように、第１部材１３は、大外径部１３１と、大外径部１３１よりも先端側の小外径部１３２と、小外径部１３２よりも先端側の薄肉部１３３と、を備えている。大外径部１３１は、小外径部１３２よりも外径が大きい。小外径部１３２は、薄肉部１３３よりも外径が大きい。第２部材１４は、大外径部１４１と、大外径部１４１よりも後端側の小外径部１４２と、小外径部１４２よりも後端側の薄肉部１４３と、を備えている。大外径部１４１は、小外径部１４２よりも外径が大きい。小外径部１４２は、薄肉部１４３よりも外径が大きい。第１部材１３の薄肉部１３３の先端と、第２部材１４の薄肉部１４３の後端とは、接触している。後端側絶縁体１０の内径（軸孔１２の径）は、第１部材１３の大外径部１３１および第２部材１４の大外径部１４１において、中央部（薄肉部１３３、１４３、小外径部１３２、１４２）よりも拡径している。 The rear end side insulator 10 includes a first member 13 on the rear end side and a second member 14 on the front end side. The first member 13 and the second member 14 are joined by the sealing members 9a and 9b. As shown in FIG. 3, the first member 13 includes a large outer diameter portion 131, a small outer diameter portion 132 on the tip side of the large outer diameter portion 131, and a thin wall portion 133 on the tip side of the small outer diameter portion 132. And have. The large outer diameter portion 131 has a larger outer diameter than the small outer diameter portion 132. The small outer diameter portion 132 has a larger outer diameter than the thin wall portion 133. The second member 14 includes a large outer diameter portion 141, a small outer diameter portion 142 on the rear end side of the large outer diameter portion 141, and a thin wall portion 143 on the rear end side of the small outer diameter portion 142. There is. The large outer diameter portion 141 has a larger outer diameter than the small outer diameter portion 142. The small outer diameter portion 142 has a larger outer diameter than the thin wall portion 143. The tip of the thin-walled portion 133 of the first member 13 and the rear end of the thin-walled portion 143 of the second member 14 are in contact with each other. The inner diameter of the rear end side insulator 10 (diameter of the shaft hole 12) is the central portion (thin wall portions 133, 143, small) in the large outer diameter portion 131 of the first member 13 and the large outer diameter portion 141 of the second member 14. The diameter is larger than the outer diameter portions 132, 142).

第１部材１３の大外径部１３１内の拡径した軸孔１２は、後端側絶縁体１０の最後端部に位置しており、後端側に向かって開放している。イグナイタプラグ１００の使用時において、大外径部１３１内の拡径した軸孔１２の内部には、図３に示すように、コネクタＣＴが収容される。このために、大外径部１３１は、コネクタ収容部と言うことができる。コネクタＣＴは、イグナイタプラグ１００に電力を供給する電源の電力供給ケーブル（図示省略）に接続されている。コネクタＣＴの先端は、図３に示すように中心電極４０の後端のコネクタ接触部４６（後述）と直接接触する。これによって、コネクタＣＴは、中心電極４０と電力供給ケーブルとを電気的に接続する。 The enlarged shaft hole 12 in the large outer diameter portion 131 of the first member 13 is located at the rearmost end portion of the rear end side insulator 10, and is open toward the rear end side. When the igniter plug 100 is used, the connector CT is housed inside the enlarged shaft hole 12 in the large outer diameter portion 131 as shown in FIG. Therefore, the large outer diameter portion 131 can be said to be a connector accommodating portion. The connector CT is connected to a power supply cable (not shown) of a power source that supplies power to the igniter plug 100. As shown in FIG. 3, the tip of the connector CT comes into direct contact with the connector contact portion 46 (described later) at the rear end of the center electrode 40. As a result, the connector CT electrically connects the center electrode 40 and the power supply cable.

図２に示すように、先端側絶縁体２０は、中央大径部２４と、中央大径部２４よりも先端側の先端小径部２５と、中央大径部２４よりも後端側の後端小径部２３と、を備えている。先端小径部２５および後端小径部２３の外径は、中央大径部２４よりも小さい。先端小径部２５の先端近傍は、発火部４２Ｃにて発生する火花が接触するため、先端小径部２５は、より低電圧で放電可能なセラミックス材料（例えば、酸化銅などの金属酸化物）で形成された先端部分２５Ａを有している。 As shown in FIG. 2, the tip side insulator 20 has a central large diameter portion 24, a tip small diameter portion 25 on the tip side of the central large diameter portion 24, and a rear end on the rear end side of the central large diameter portion 24. It is provided with a small diameter portion 23. The outer diameters of the tip small diameter portion 25 and the rear end small diameter portion 23 are smaller than those of the central large diameter portion 24. Since sparks generated in the ignition portion 42C come into contact with the vicinity of the tip of the tip small diameter portion 25, the tip small diameter portion 25 is formed of a ceramic material (for example, a metal oxide such as copper oxide) that can be discharged at a lower voltage. It has a tip portion 25A that has been discharged.

先端側絶縁体２０の軸孔２２は、中央大径部２４の先端部分より後端側において、先端側の小内径孔２２Ｂより内径が大きな大内径孔２２Ａ（図２）となっている。先端側絶縁体２０において、小内径孔２２Ｂが形成された部分と大内径孔２２Ａが形成された部分との間に段部２６が形成されている。 The shaft hole 22 of the front end side insulator 20 is a large inner diameter hole 22A (FIG. 2) having an inner diameter larger than that of the small inner diameter hole 22B on the front end side on the rear end side of the front end portion of the central large diameter portion 24. In the tip-side insulator 20, a step portion 26 is formed between a portion where the small inner diameter hole 22B is formed and a portion where the large inner diameter hole 22A is formed.

金属筒部材７０は、軸線ＡＸに沿って延びる金属製の略円筒状の部材である。金属筒部材７０は、例えば、ステンレスで形成されている。図３に示すように、金属筒部材７０は、筒状部７１と、筒状部７１よりも先端側の鍔部７５と、を備えている。鍔部７５は、筒状部７１よりも大きな外径を有している。筒状部７１は、後端側絶縁体１０の中央部（薄肉部１３３、１４３、小外径部１３２、１４２）の軸孔１２に挿通されている。鍔部７５は、後端側絶縁体１０の大外径部１４１の拡径された軸孔１２内に位置している。金属筒部材７０は、シール部材９ｂによって、後端側絶縁体１０に固定されている。 The metal cylinder member 70 is a metal substantially cylindrical member extending along the axis AX. The metal cylinder member 70 is made of, for example, stainless steel. As shown in FIG. 3, the metal tubular member 70 includes a tubular portion 71 and a flange portion 75 on the tip side of the tubular portion 71. The collar portion 75 has a larger outer diameter than the tubular portion 71. The tubular portion 71 is inserted into the shaft hole 12 of the central portion (thin-walled portions 133, 143, small outer diameter portions 132, 142) of the rear end side insulator 10. The flange portion 75 is located in the enlarged shaft hole 12 of the large outer diameter portion 141 of the rear end side insulator 10. The metal cylinder member 70 is fixed to the rear end side insulator 10 by the seal member 9b.

中心電極４０は、軸線ＡＸに沿って延びる棒状の部材である。中心電極４０は、先端部材４２と、先端部材４２よりも後端側に設けられた中央部材４３と、中央部材４３よりも後端側に設けられた後端部材４４と、の３個の部材を溶接によって接合して形成されている。先端部材４２は、火花放電が行われる発火部４２Ｃ（後述）を含むため、中央部材４３や後端部材４４よりも耐熱性に優れた金属材料、本実施形態では、ニッケル（Ｎｉ）を主成分としクロム（Ｃｒ）や鉄（Ｆｅ）を含む合金（具体例としては、ＮＣＦ６００、ＮＣＦ６０１）を用いて形成されている。中央部材４３と後端部材４４とは、先端部材４２よりも比抵抗が小さく導電性に優れた金属材料（比抵抗が低い金属材料）、本実施形態では、純Ｎｉを用いて形成されている。 The center electrode 40 is a rod-shaped member extending along the axis AX. The center electrode 40 has three members: a tip member 42, a center member 43 provided on the rear end side of the tip member 42, and a rear end member 44 provided on the rear end side of the center member 43. Are joined by welding. Since the tip member 42 includes an ignition portion 42C (described later) in which spark discharge is performed, a metal material having better heat resistance than the central member 43 and the rear end member 44, in this embodiment, nickel (Ni) is the main component. It is formed by using an alloy containing chromium (Cr) and iron (Fe) (specific examples are NCF600 and NCF601). The central member 43 and the rear end member 44 are formed by using a metal material having a smaller specific resistance and excellent conductivity (a metal material having a lower specific resistance) than the front end member 42, and in this embodiment, pure Ni. ..

中心電極４０は、絶縁体１の軸孔１２、２２に挿通されている。具体的には、先端部材４２の全体と、中央部材４３の先端側の部分とは、先端側絶縁体２０の軸孔２２に挿通されている。後端部材４４の後端側の部分は、後端側絶縁体１０の軸孔１２に挿通されている。 The center electrode 40 is inserted through the shaft holes 12 and 22 of the insulator 1. Specifically, the entire tip member 42 and the tip-side portion of the central member 43 are inserted into the shaft hole 22 of the tip-side insulator 20. The rear end side portion of the rear end member 44 is inserted into the shaft hole 12 of the rear end side insulator 10.

図２に示すように、先端部材４２は、棒状部４２Ａと、棒状部４２Ａよりも後端側の鍔部４２Ｂと、を備えている。鍔部４２Ｂは、棒状部４２Ａよりも大きな外径を有している。棒状部４２Ａは、先端側絶縁体２０の小内径孔２２Ｂ内に位置し、鍔部４２Ｂは、先端側絶縁体２０の段部２６に先端側から支持されている。先端部材４２の先端部分（棒状部４２Ａの先端部分）は、接地電極５０との間に火花ギャップを形成する発火部４２Ｃである。 As shown in FIG. 2, the tip member 42 includes a rod-shaped portion 42A and a flange portion 42B on the rear end side of the rod-shaped portion 42A. The collar portion 42B has a larger outer diameter than the rod-shaped portion 42A. The rod-shaped portion 42A is located in the small inner diameter hole 22B of the tip-side insulator 20, and the flange portion 42B is supported by the step portion 26 of the tip-side insulator 20 from the tip side. The tip portion of the tip member 42 (the tip portion of the rod-shaped portion 42A) is an ignition portion 42C that forms a spark gap with the ground electrode 50.

中央部材４３の先端は、先端部材４２の後端、すなわち、鍔部４２Ｂの後端に溶接されている。中央部材４３の先端側の部分は、先端側絶縁体２０の大内径孔２２Ａ内に位置している。大内径孔２２Ａにおいて、中心電極４０（鍔部４２Ｂおよび中央部材４３）と先端側絶縁体２０の内周面との間に、粉末２ａ（例えば、滑石）、および、粉末２ａとは材質が異なるアルミナ滑石７が充填されている。これによって、中心電極４０の先端側の部分は、先端側絶縁体２０に固定されている。 The tip of the central member 43 is welded to the rear end of the tip member 42, that is, the rear end of the flange portion 42B. The tip end side portion of the central member 43 is located in the large inner diameter hole 22A of the tip end side insulator 20. In the large inner diameter hole 22A, the material is different from the powder 2a (for example, talc) and the powder 2a between the center electrode 40 (flange portion 42B and the central member 43) and the inner peripheral surface of the tip side insulator 20. Alumina talc 7 is filled. As a result, the tip-side portion of the center electrode 40 is fixed to the tip-side insulator 20.

後端部材４４の先端は、後端側絶縁体１０と先端側絶縁体２０との間に位置し、中央部材４３の後端に溶接されている。後端部材４４の後端側の部分は、後端側絶縁体１０の軸孔１２と、金属筒部材７０と、に遊嵌状に挿通されている。すなわち、金属筒部材７０の筒状部７１の内周面と、後端部材４４の外周面と、の間には、僅かな隙間があり、互いに固定されていない。例えば、本実施形態では、筒状部７１の内周面と、後端部材４４の外周面と、の間のクリアランスは、０．０１ｍｍ〜０．０５ｍｍである。この程度のクリアランスとすることで、後述する絶縁粉末５が、筒状部７１の内周面と、後端部材４４の外周面と、の間に浸入することを抑制しつつ、金属筒部材７０および先端側絶縁体２０に対して、後端部材４４を遊嵌状に維持することができる。 The tip of the rear end member 44 is located between the rear end side insulator 10 and the front end side insulator 20, and is welded to the rear end of the central member 43. The rear end side portion of the rear end member 44 is loosely fitted through the shaft hole 12 of the rear end side insulator 10 and the metal cylinder member 70. That is, there is a slight gap between the inner peripheral surface of the tubular portion 71 of the metal tubular member 70 and the outer peripheral surface of the rear end member 44, and they are not fixed to each other. For example, in the present embodiment, the clearance between the inner peripheral surface of the tubular portion 71 and the outer peripheral surface of the rear end member 44 is 0.01 mm to 0.05 mm. With this clearance, the metal tubular member 70 is prevented from infiltrating between the inner peripheral surface of the tubular portion 71 and the outer peripheral surface of the rear end member 44, which will be described later. The rear end member 44 can be maintained in a loose fit with respect to the front end side insulator 20.

後端部材４４の後端に位置する上述したコネクタ接触部４６（図３）は、後端側絶縁体１０の大外径部１３１（コネクタ収容部）の拡径した軸孔１２内に位置している。 The above-mentioned connector contact portion 46 (FIG. 3) located at the rear end of the rear end member 44 is located in the enlarged shaft hole 12 of the large outer diameter portion 131 (connector accommodating portion) of the rear end side insulator 10. ing.

以上の説明から解るように、中心電極４０は、先端側絶縁体２０の先端近傍部分（先端部）から後端側絶縁体１０の後端近傍部分（後端部）まで延びている。 As can be seen from the above description, the center electrode 40 extends from a portion near the tip (tip portion) of the front end side insulator 20 to a portion near the rear end (rear end portion) of the rear end side insulator 10.

主体金具６０は、導電性の金属材料（例えば、低炭素鋼材やＮｉ合金）で形成され、例えば、エンジン（図示省略）にイグナイタプラグ１００を固定するための軸線方向に延びる略円筒状の金具である。主体金具６０には、軸線ＡＸに沿って貫通する貫通孔６９が形成されている。主体金具６０の貫通孔６９内には、絶縁体１および中心電極４０が収容されている。このために、主体金具６０は、後端側絶縁体１０および先端側絶縁体２０の径方向の周囲（すなわち、外周）に配置されている。主体金具６０の後端は、後端側絶縁体１０の後端よりも後端側に位置し、主体金具６０の先端は、先端側絶縁体２０の先端よりも先端側に位置している。 The main metal fitting 60 is formed of a conductive metal material (for example, low carbon steel material or Ni alloy), and is, for example, a substantially cylindrical metal fitting extending in the axial direction for fixing the igniter plug 100 to an engine (not shown). be. The main metal fitting 60 is formed with a through hole 69 penetrating along the axis AX. The insulator 1 and the center electrode 40 are housed in the through hole 69 of the main metal fitting 60. For this purpose, the main metal fitting 60 is arranged around the rear end side insulator 10 and the front end side insulator 20 in the radial direction (that is, the outer circumference). The rear end of the main metal fitting 60 is located closer to the rear end side than the rear end of the rear end side insulator 10, and the tip of the main metal fitting 60 is located closer to the tip side than the tip of the front end side insulator 20.

図１に示すように、主体金具６０は、３個の同軸に並んだ部材、すなわち、後端側の後端金具６１と、先端側の先端金具６３と、後端金具６１と先端金具６３との間の中間金具６２と、が接合されることによって形成されている。後端金具６１と中間金具６２とは、溶接部ＷＰ１によって接合され、中間金具６２と先端金具６３とは、溶接部ＷＰ２によって接合されている。溶接部ＷＰ１、ＷＰ２は、例えば、レーザ溶接によって形成される溶接部である。 As shown in FIG. 1, the main metal fitting 60 includes three coaxially arranged members, that is, a rear end metal fitting 61 on the rear end side, a tip metal fitting 63 on the front end side, and a rear end metal fitting 61 and a tip metal fitting 63. It is formed by joining the intermediate metal fitting 62 between the two. The rear end fitting 61 and the intermediate fitting 62 are joined by the welded portion WP1, and the intermediate fitting 62 and the tip fitting 63 are joined by the welded portion WP2. The welded portions WP1 and WP2 are welded portions formed by, for example, laser welding.

主体金具６０は、後端側から順に、ネジ部６４と、工具係合部６５と、２個の鍔状の座部６６、６７と、を備えている。ネジ部６４は、上述したコネクタＣＴと電力供給ケーブルとが取り付けられたキャップを固定するための雄ネジである。工具係合部６５は、プラグレンチが係合するために面取りが成された部分である。後端側の座部６６は、イグナイタプラグ１００をエンジンなどに取り付ける際に、イグナイタプラグ１００をエンジン側（先端側）に押し付けるバネ（図示省略）を支持する。先端側の座部６７よりも先端側の小外径部６８は、エンジンなどに取り付けられた際に、燃焼ガスに曝される部分である。 The main metal fitting 60 includes a screw portion 64, a tool engaging portion 65, and two collar-shaped seat portions 66 and 67 in this order from the rear end side. The screw portion 64 is a male screw for fixing the cap to which the connector CT and the power supply cable described above are attached. The tool engaging portion 65 is a chamfered portion for engaging the plug wrench. The seat portion 66 on the rear end side supports a spring (not shown) that presses the igniter plug 100 against the engine side (tip side) when the igniter plug 100 is attached to an engine or the like. The small outer diameter portion 68 on the tip side of the seat portion 67 on the tip side is a portion exposed to combustion gas when attached to an engine or the like.

後端金具６１の貫通孔６９内には、シール部材９ａ、９ｂによって、上述した後端側絶縁体１０が固定されている。 The above-mentioned rear end side insulator 10 is fixed in the through hole 69 of the rear end metal fitting 61 by the sealing members 9a and 9b.

主体金具６０において、中間金具６２の先端は、線パッキン６と滑石２ｂと板パッキン８とを介して、先端側絶縁体２０の中央大径部２４を後端側から先端側に押さえている。また、主体金具６０の先端に形成された接地電極５０（後述）の後端向き面５０ｂは、先端側絶縁体２０の先端小径部２５の先端を先端側から支持している。これによって、主体金具６０の貫通孔６９内に、先端側絶縁体２０が固定されている。 In the main metal fitting 60, the tip of the intermediate metal fitting 62 presses the central large diameter portion 24 of the front end side insulator 20 from the rear end side to the front end side via the wire packing 6, the talc 2b, and the plate packing 8. Further, the ground electrode 50 (described later) formed at the tip of the main metal fitting 60 has a rear end facing surface 50b that supports the tip of the tip small diameter portion 25 of the tip side insulator 20 from the tip side. As a result, the tip side insulator 20 is fixed in the through hole 69 of the main metal fitting 60.

主体金具６０の貫通孔６９内の板パッキン８よりも先端側において、主体金具６０の内周面と、先端側絶縁体２０の外周面と、の間には、筒状空間ＳＰ１が形成されている。 A tubular space SP1 is formed between the inner peripheral surface of the main metal fitting 60 and the outer peripheral surface of the front end side insulator 20 on the tip side of the plate packing 8 in the through hole 69 of the main metal fitting 60. There is.

先端金具６３の座部６７の後端側の壁面には、周方向に分散して配置され、壁面を軸線方向と垂直に貫通する複数個（例えば６個）の入口孔６０ｉが形成されている。入口孔６０ｉによって、主体金具６０内の筒状空間ＳＰ１と、外部と、が連通し、冷却のための外部のガス（冷却流体とも呼ぶ）が筒状空間ＳＰ１内に導入可能とされる。 A plurality of (for example, 6) inlet holes 60i are formed on the wall surface of the tip metal fitting 63 on the rear end side of the seat portion 67 so as to be dispersed in the circumferential direction and penetrate the wall surface perpendicularly to the axial direction. .. The inlet hole 60i allows the tubular space SP1 in the main metal fitting 60 and the outside to communicate with each other so that an external gas (also referred to as a cooling fluid) for cooling can be introduced into the tubular space SP1.

図４は、イグナイタプラグ１００の先端を軸線ＡＸに沿って先端側から後端側に向かって見た図である。図４では、構成する部材の種類が解りやすいように、各部材に、図２の断面図と同様のハッチングを付している。図４では、座部６７および座部６７より後端側の図示は省略されている。 FIG. 4 is a view of the tip of the igniter plug 100 viewed from the front end side to the rear end side along the axis AX. In FIG. 4, each member is hatched in the same manner as in the cross-sectional view of FIG. 2 so that the types of the constituent members can be easily understood. In FIG. 4, the seat portion 67 and the rear end side of the seat portion 67 are not shown.

図４に示すように、接地電極５０は、主体金具６０の先端に形成され、軸線方向に貫通する貫通孔５７を有する円環状の部分である。接地電極５０は、耐腐食性と耐熱性が高い金属、例えば、ＮｉやＮｉ合金、タングステンで形成されている。本実施形態では、主体金具６０の先端金具６３がＮｉ合金で形成され、接地電極５０は、先端金具６３と一体に形成されている。これに代えて、接地電極５０は、主体金具６０とは別部材で形成され、主体金具６０の先端に溶接によって接合されていても良い。 As shown in FIG. 4, the ground electrode 50 is an annular portion formed at the tip of the main metal fitting 60 and having a through hole 57 penetrating in the axial direction. The ground electrode 50 is made of a metal having high corrosion resistance and heat resistance, for example, Ni, Ni alloy, or tungsten. In the present embodiment, the tip metal fitting 63 of the main metal fitting 60 is formed of Ni alloy, and the ground electrode 50 is integrally formed with the tip metal fitting 63. Instead of this, the ground electrode 50 may be formed of a member separate from the main metal fitting 60 and may be joined to the tip of the main metal fitting 60 by welding.

接地電極５０には、図２、図４に示すように、内周縁よりも径方向外側（すなわち、貫通孔５７よりも径方向外側）に位置し、周方向に分散して配置され、接地電極５０を軸線方向に貫通する複数個（本実施形態では１２個）の出口孔５０ｏが形成されている。また、図２に示すように、小外径部６８の先端近傍の壁面にも、周方向に分散して配置され、壁面を軸線方向と垂直に貫通する複数個（例えば８個）の出口孔６０ｏが形成されている。出口孔５０ｏ、６０ｏによって、主体金具６０内の筒状空間ＳＰ１と、外部と、が連通し、冷却のための外部のガス（冷却流体とも呼ぶ）が筒状空間ＳＰ１内から排出可能とされる。このように、上述した入口孔６０ｉよりも先端側に出口孔５０ｏ、６０ｏが形成されることで、図２で矢印で示すように、筒状空間ＳＰ１内を、後端側からより高温な先端側に向かって冷却流体が流動する。 As shown in FIGS. 2 and 4, the ground electrode 50 is located radially outside the inner peripheral edge (that is, radially outside the through hole 57), is dispersed in the circumferential direction, and is a ground electrode. A plurality of outlet holes 50o (12 in this embodiment) penetrating the 50 in the axial direction are formed. Further, as shown in FIG. 2, a plurality of (for example, eight) outlet holes are also arranged on the wall surface near the tip of the small outer diameter portion 68 in the circumferential direction and penetrate the wall surface perpendicularly to the axial direction. 60o is formed. The outlet holes 50o and 60o allow the tubular space SP1 in the main metal fitting 60 and the outside to communicate with each other so that an external gas for cooling (also referred to as a cooling fluid) can be discharged from the tubular space SP1. .. As described above, by forming the outlet holes 50o and 60o on the tip side of the inlet hole 60i described above, as shown by the arrow in FIG. 2, the tip in the tubular space SP1 has a higher temperature from the rear end side. The cooling fluid flows toward the side.

接地電極５０の貫通孔５７内には、中心電極４０の発火部４２Ｃ（上述）が位置しており、接地電極５０の貫通孔５７を形成する壁面と、発火部４２Ｃの側面と、の間に放電のための間隙Ｇ（火花ギャップ）が形成される。 The ignition portion 42C (described above) of the center electrode 40 is located in the through hole 57 of the ground electrode 50, and is between the wall surface forming the through hole 57 of the ground electrode 50 and the side surface of the ignition portion 42C. A gap G (spark gap) for discharge is formed.

絶縁筒部材８０は、絶縁性の材料（例えば、アルミナ）によって形成された円筒状の部材である。絶縁筒部材８０は、中心電極４０のうち、軸線方向の一部の外周に配置されている。すなわち、中心電極４０のうちの一部分は、絶縁筒部材８０に挿通されている。絶縁筒部材８０の先端は、先端側絶縁体２０の後端小径部２３の内部に位置している（図２）。絶縁筒部材８０の後端は、後端側絶縁体１０の大外径部１４１の内部に位置している（図３）。したがって、本実施形態では、絶縁筒部材８０は、中心電極４０のうち、後端側絶縁体１０の先端から先端側絶縁体２０の後端までの範囲を含む軸線方向の範囲を覆っている。絶縁筒部材８０の内周面と中心電極４０の外周面とは、接着材３によって接着されている。 The insulating cylinder member 80 is a cylindrical member formed of an insulating material (for example, alumina). The insulating cylinder member 80 is arranged on the outer periphery of a part of the center electrode 40 in the axial direction. That is, a part of the center electrode 40 is inserted through the insulating cylinder member 80. The tip of the insulating cylinder member 80 is located inside the rear end small diameter portion 23 of the tip side insulator 20 (FIG. 2). The rear end of the insulating cylinder member 80 is located inside the large outer diameter portion 141 of the rear end side insulator 10 (FIG. 3). Therefore, in the present embodiment, the insulating cylinder member 80 covers the axial range of the center electrode 40, including the range from the front end of the rear end side insulator 10 to the rear end of the front end side insulator 20. The inner peripheral surface of the insulating cylinder member 80 and the outer peripheral surface of the center electrode 40 are adhered by an adhesive material 3.

絶縁筒部材８０の外周面と、主体金具６０の内周面（後端金具６１と中間金具６２との内周面）と、の間には、絶縁粉末５が充填されている。絶縁粉末５は、絶縁性の材料で形成された粉末であり、本実施形態では、マグネシア（ＭｇＯ、酸化マグネシウムとも呼ぶ）の粉末である。絶縁粉末５は、後端側絶縁体１０の大外径部１４１の内周面と絶縁筒部材８０の外周面との間、および、大外径部１４１の内周面と金属筒部材７０の鍔部７５との間にも充填されている（図３）。絶縁粉末５は、さらに、先端側絶縁体２０の後端小径部２３の内周面と絶縁筒部材８０の外周面との間、および、後端小径部２３の内周面と中心電極４０（中央部材４３）の外周面との間にも充填されている（図２）。 The insulating powder 5 is filled between the outer peripheral surface of the insulating cylinder member 80 and the inner peripheral surface of the main metal fitting 60 (the inner peripheral surface of the rear end metal fitting 61 and the intermediate metal fitting 62). The insulating powder 5 is a powder formed of an insulating material, and in the present embodiment, it is a powder of magnesia (MgO, also referred to as magnesium oxide). The insulating powder 5 is provided between the inner peripheral surface of the large outer diameter portion 141 of the rear end side insulator 10 and the outer peripheral surface of the insulating cylinder member 80, and between the inner peripheral surface of the large outer diameter portion 141 and the metal cylinder member 70. It is also filled between the collar portion 75 (FIG. 3). Further, the insulating powder 5 is provided between the inner peripheral surface of the rear end small diameter portion 23 of the front end side insulator 20 and the outer peripheral surface of the insulating cylinder member 80, and the inner peripheral surface of the rear end small diameter portion 23 and the center electrode 40 ( It is also filled between the central member 43) and the outer peripheral surface (FIG. 2).

中間金具６２の外壁に形成された貫通孔６２Ａは、イグナイタプラグ１００の製造時に、絶縁粉末５を充填するための孔である。貫通孔６２Ａは、貫通孔６２Ａに嵌合する栓部材４によって塞がれている。 The through hole 62A formed in the outer wall of the intermediate metal fitting 62 is a hole for filling the insulating powder 5 at the time of manufacturing the igniter plug 100. The through hole 62A is closed by a plug member 4 that fits into the through hole 62A.

以上説明したイグナイタプラグ１００の動作を説明する。中心電極４０と主体金具６０とに、駆動電圧が印加されると、間隙Ｇに、先端側絶縁体２０の先端部分２５Ａに沿う放電が発生し、貫通孔５７から該放電によって生じたプラズマや火炎が先端側に放出される。 The operation of the igniter plug 100 described above will be described. When a driving voltage is applied to the center electrode 40 and the main metal fitting 60, a discharge is generated in the gap G along the tip portion 25A of the tip side insulator 20, and plasma or flame generated by the discharge is generated from the through hole 57. Is discharged to the tip side.

また、イグナイタプラグ１００が使用される際には、図２に筒状空間ＳＰ１内に矢印で示すように、入口孔６０ｉを介して筒状空間ＳＰ１に冷却流体（例えば空気）が供給される。供給された冷却流体の一部は、筒状空間ＳＰ１の先端側に流動して、出口孔５０ｏ、６０ｏを通って外部に排出される。このような冷却流体の流れにより、主に、先端側絶縁体２０の先端小径部２５が冷却される。 When the igniter plug 100 is used, a cooling fluid (for example, air) is supplied to the tubular space SP1 through the inlet hole 60i as shown by an arrow in the tubular space SP1 in FIG. A part of the supplied cooling fluid flows toward the tip end side of the tubular space SP1 and is discharged to the outside through the outlet holes 50o and 60o. Such a flow of the cooling fluid mainly cools the tip small diameter portion 25 of the tip side insulator 20.

Ａ−２．イグナイタプラグ１００の製造方法：
イグナイタプラグ１００の製造では、後端金具６１に絶縁体１０を組付けた後端側モジュール６１Ｍが作成される。図５は、後端側モジュール６１Ｍの製造の説明図である。まず、図５（Ａ）の組付治具２００が用意される。組付治具２００は、例えば、金属製の治具であり、台部２１０と、大径部２２０と、小径部２３０と、を備えている。大径部２２０は、台部２１０の上面から上方に延びる円筒状の部分である。小径部２３０は、大径部２２０と同軸であり、大径部２２０の上方に位置する円筒状の部材である。小径部２３０の外径は、大径部２２０よりも小さい。 A-2. Manufacturing method of igniter plug 100:
In the manufacture of the igniter plug 100, a rear end side module 61M in which the insulator 10 is attached to the rear end metal fitting 61 is created. FIG. 5 is an explanatory view of manufacturing the rear end side module 61M. First, the assembly jig 200 shown in FIG. 5A is prepared. The assembly jig 200 is, for example, a metal jig, and includes a base portion 210, a large diameter portion 220, and a small diameter portion 230. The large diameter portion 220 is a cylindrical portion extending upward from the upper surface of the base portion 210. The small diameter portion 230 is a cylindrical member that is coaxial with the large diameter portion 220 and is located above the large diameter portion 220. The outer diameter of the small diameter portion 230 is smaller than that of the large diameter portion 220.

まず、図５（Ｂ）に示すように、組付治具２００の小径部２３０の先端に、先端側を（鍔部７５側）を下方にし後端側（筒状部７１側）を上方にした姿勢で金属筒部材７０が載置される。そして、金属筒部材７０の先端が、第２部材１４の軸孔１２に後端側から挿通されるように、第２部材１４が、組付治具２００に載置される。第２部材１４の大外径部１４１には、組付治具２００の大径部２２０の先端部分が挿通される。さらに、第２部材１４の全体が後端金具６１の貫通孔６９内に配置されるように、後端金具６１が組付治具２００に載置される。後端金具６１の先端が台部２１０の上面に接した状態で、後端金具６１の内部の適切な軸線方向の位置に、第２部材１４および金属筒部材７０が配置されるように、大径部２２０および小径部２３０の高さが設定されている。 First, as shown in FIG. 5B, the tip end side (flange portion 75 side) is downward and the rear end side (cylindrical portion 71 side) is upward at the tip end of the small diameter portion 230 of the assembly jig 200. The metal cylinder member 70 is placed in this posture. Then, the second member 14 is placed on the assembly jig 200 so that the tip of the metal cylinder member 70 is inserted into the shaft hole 12 of the second member 14 from the rear end side. The tip portion of the large diameter portion 220 of the assembly jig 200 is inserted into the large outer diameter portion 141 of the second member 14. Further, the rear end fitting 61 is placed on the assembly jig 200 so that the entire second member 14 is arranged in the through hole 69 of the rear end fitting 61. Large so that the second member 14 and the metal cylinder member 70 are arranged at appropriate axial positions inside the rear end fitting 61 with the tip of the rear end fitting 61 in contact with the upper surface of the base 210. The heights of the diameter portion 220 and the small diameter portion 230 are set.

この状態で、図５（Ｃ）に示すように、金属筒部材７０の孔が上方から棒部材２４０で塞がれる。そして、後端金具６１の貫通孔６９内に、シール部材９ａ、９ｂの材料となるガラス粉末９Ｐが所定の量だけ充填される。 In this state, as shown in FIG. 5C, the hole of the metal cylinder member 70 is closed by the rod member 240 from above. Then, the through hole 69 of the rear end fitting 61 is filled with a predetermined amount of glass powder 9P, which is a material for the sealing members 9a and 9b.

次に、図５（Ｄ）に示すように、後端金具６１を、ガラス粉末９Ｐの軟化点よりも高い所定温度まで加熱し、所定温度に加熱した状態で、貫通孔６９の後端側の開口から絶縁体１０を構成する第１部材１３が挿入される。これによって、第１部材１３の先端でガラス粉末９Ｐを圧縮するように、第１部材１３が押し込まれて、シール部材９ａ、９ｂが形成される。この結果、後端金具６１の貫通孔６９内に絶縁体１０がシール部材９ａ、９ｂによって固定された後端側モジュール６１Ｍが完成する。 Next, as shown in FIG. 5 (D), the rear end fitting 61 is heated to a predetermined temperature higher than the softening point of the glass powder 9P, and in a state of being heated to a predetermined temperature, on the rear end side of the through hole 69. The first member 13 constituting the insulator 10 is inserted through the opening. As a result, the first member 13 is pushed in so as to compress the glass powder 9P at the tip of the first member 13, and the seal members 9a and 9b are formed. As a result, the rear end side module 61M in which the insulator 10 is fixed by the sealing members 9a and 9b in the through hole 69 of the rear end metal fitting 61 is completed.

イグナイタプラグ１００の先端側は、後端側モジュール６１Ｍとは別に作成される。まず、中心電極４０のうち、先端部材４２と中央部材４３とが溶接される。溶接された先端部材４２と中央部材４３とは、先端側絶縁体２０の軸孔２２内に後端側から挿入される。軸孔２２内に、滑石２ａが充填され、アルミナ滑石７が取り付けられる。これによって、先端側絶縁体２０に対して、先端部材４２および中央部材４３が固定される。 The front end side of the igniter plug 100 is created separately from the rear end side module 61M. First, of the center electrode 40, the tip member 42 and the center member 43 are welded. The welded tip member 42 and the center member 43 are inserted into the shaft hole 22 of the tip side insulator 20 from the rear end side. The shaft hole 22 is filled with talc 2a, and the alumina talc 7 is attached. As a result, the tip member 42 and the center member 43 are fixed to the tip side insulator 20.

先端金具６３の貫通孔６９に、先端部材４２および中央部材４３が固定された先端側絶縁体２０が挿入される。先端金具６３の内周面と先端側絶縁体２０の外周面との間に、線パッキン６、板パッキン８の配置および滑石２ｂの充填が行われる。 The tip side insulator 20 to which the tip member 42 and the center member 43 are fixed is inserted into the through hole 69 of the tip metal fitting 63. The wire packing 6 and the plate packing 8 are arranged and the talc 2b is filled between the inner peripheral surface of the tip metal fitting 63 and the outer peripheral surface of the tip side insulator 20.

さらに、中央部材４３の後端に後端部材４４が溶接されて中心電極４０が形成される。そして、中心電極４０の外周面に接着材３が塗布された後に、中心電極４０は絶縁筒部材８０に挿通される。これによって、中心電極４０に絶縁筒部材８０が固定される。 Further, the rear end member 44 is welded to the rear end of the central member 43 to form the center electrode 40. Then, after the adhesive material 3 is applied to the outer peripheral surface of the center electrode 40, the center electrode 40 is inserted into the insulating cylinder member 80. As a result, the insulating cylinder member 80 is fixed to the center electrode 40.

その後、先端金具６３の後端に中間金具６２が溶接される。さらに、中間金具６２の後端に、後端金具６１を含む後端側モジュール６１Ｍが取り付けられ、後端金具６１と中間金具６２とが溶接される。このとき、後端側モジュール６１Ｍの金属筒部材７０には、中心電極４０の後端部材４４が挿通される。 After that, the intermediate metal fitting 62 is welded to the rear end of the tip metal fitting 63. Further, a rear end side module 61M including the rear end metal fitting 61 is attached to the rear end of the intermediate metal fitting 62, and the rear end metal fitting 61 and the intermediate metal fitting 62 are welded to each other. At this time, the rear end member 44 of the center electrode 40 is inserted into the metal cylinder member 70 of the rear end side module 61M.

次に、中間金具６２に形成された貫通孔６２Ａから、貫通孔６９内に絶縁粉末５が充填される。絶縁粉末５が充填された後に、貫通孔６２Ａが栓部材４によって塞がれる。栓部材４は溶接によって中間金具６２に固定される。以上の工程を経て、イグナイタプラグ１００が完成する。 Next, the insulating powder 5 is filled in the through hole 69 from the through hole 62A formed in the intermediate metal fitting 62. After the insulating powder 5 is filled, the through hole 62A is closed by the plug member 4. The stopper member 4 is fixed to the intermediate metal fitting 62 by welding. Through the above steps, the igniter plug 100 is completed.

以上説明した本実施形態のイグナイタプラグ１００によれば、中心電極４０は、先端側絶縁体２０の先端部から後端側絶縁体の後端部まで延びており、その後端部分にコネクタＣＴと直接接触するコネクタ接触部４６を有している（図３）。そして、中心電極４０は、先端側絶縁体２０に支持されつつ（図２）、後端側絶縁体１０に遊嵌状に挿通されている（図３）。コネクタ接触部４６は、コネクタ収容部としての大外径部１３１の内部に配置されている（図３）。この結果、中心電極４０は、コネクタＣＴと直接接触するので、他部材（例えば、端子金具）を介してコネクタＣＴと接触する場合と比較して、コネクタＣＴと中心電極４０間の抵抗を低減して導電性を向上できる。また、中心電極４０は、後端側絶縁体１０に遊嵌状に挿通されるので、中心電極４０が熱膨張によって伸長した場合に湾曲することを抑制できる。したがって、コネクタＣＴと中心電極４０との間の導電性の向上と、熱膨張時の中心電極４０の湾曲の抑制と、を両立できる。 According to the igniter plug 100 of the present embodiment described above, the center electrode 40 extends from the front end portion of the front end side insulator 20 to the rear end portion of the rear end side insulator, and is directly connected to the connector CT at the rear end portion. It has a connector contact portion 46 that comes into contact (FIG. 3). The center electrode 40 is loosely fitted through the rear end side insulator 10 while being supported by the front end side insulator 20 (FIG. 2). The connector contact portion 46 is arranged inside a large outer diameter portion 131 as a connector accommodating portion (FIG. 3). As a result, since the center electrode 40 comes into direct contact with the connector CT, the resistance between the connector CT and the center electrode 40 is reduced as compared with the case where the center electrode 40 comes into contact with the connector CT via another member (for example, a terminal fitting). The conductivity can be improved. Further, since the center electrode 40 is loosely inserted into the rear end side insulator 10, it is possible to prevent the center electrode 40 from bending when it is extended due to thermal expansion. Therefore, it is possible to improve the conductivity between the connector CT and the center electrode 40 and suppress the curvature of the center electrode 40 at the time of thermal expansion.

より詳しく説明する。図６は、比較形態のイグナイタプラグ１００Ｘの説明図である。図６には、イグナイタプラグ１００Ｘの後端側の一部分を軸線ＡＸを含む平面で切断した断面が示されている。イグナイタプラグ１００Ｘでは、絶縁体１０Ｘの後端近傍において、軸孔１２Ｘ内に、中心電極４０Ｘとは別体の端子金具９０Ｘが配置されている。この端子金具９０Ｘには、雄ネジが形成されている。この雄ネジが絶縁体１０Ｘの内周面に形成された雌ネジと係合することで、端子金具９０Ｘは、絶縁体１０Ｘに固定されている。中心電極４０Ｘの後端は、端子金具９０Ｘの先端側に開口する孔に挿入されており、中心電極４０Ｘと端子金具９０Ｘとは、直接接触しており、該接触によって、中心電極４０と端子金具９０Ｘとは電気的に接続されている。電源を供給するためのコネクタＣＴＸは、主体金具６０Ｘおよび絶縁体１０Ｘの後端側の開口から挿入されて、端子金具９０Ｘと接触する。 It will be explained in more detail. FIG. 6 is an explanatory diagram of the igniter plug 100X in the comparative form. FIG. 6 shows a cross section obtained by cutting a part of the rear end side of the igniter plug 100X in a plane including the axis AX. In the igniter plug 100X, a terminal metal fitting 90X separate from the center electrode 40X is arranged in the shaft hole 12X in the vicinity of the rear end of the insulator 10X. A male screw is formed on the terminal fitting 90X. The terminal fitting 90X is fixed to the insulator 10X by engaging the male screw with the female screw formed on the inner peripheral surface of the insulator 10X. The rear end of the center electrode 40X is inserted into a hole opened on the tip side of the terminal metal fitting 90X, and the center electrode 40X and the terminal metal fitting 90X are in direct contact with each other. It is electrically connected to the 90X. The connector CTX for supplying power is inserted through the opening on the rear end side of the main metal fitting 60X and the insulator 10X, and comes into contact with the terminal metal fitting 90X.

ところで、イグナイタプラグ１００の使用時には、中心電極４０は、燃焼ガスに曝されるために、高温（例えば、摂氏１０００度）になる。このために、中心電極４０は、熱膨張によって伸長する。例えば、航空機用のジェットエンジンのイグナイタプラグ１００では、中心電極４０の長さは、３０ｃｍ以上になり得る。この場合に、常温から摂氏１０００度まで加熱されると、中心電極４０は、数ｍｍ（例えば、約５ｍｍ）伸長する。 By the way, when the igniter plug 100 is used, the center electrode 40 becomes high temperature (for example, 1000 degrees Celsius) because it is exposed to the combustion gas. For this reason, the center electrode 40 is elongated by thermal expansion. For example, in an igniter plug 100 of a jet engine for an aircraft, the length of the center electrode 40 can be 30 cm or more. In this case, when heated from room temperature to 1000 degrees Celsius, the center electrode 40 extends by several mm (for example, about 5 mm).

この場合に、イグナイタプラグ１００Ｘにおいて、中心電極４０Ｘが端子金具９０Ｘに固定されていると、絶縁体１０Ｘが端子金具９０Ｘおよび中心電極４０Ｘを保持する形態となる。すると、熱膨張によって中心電極４０Ｘが伸長した場合に、中心電極４０Ｘが湾曲する。この結果、例えば、中心電極４０Ｘが主体金具６０Ｘに近づき、フラッシュオーバが発生するおそれがある。一方で、中心電極４０Ｘの湾曲を抑制するために、例えば、中心電極４０Ｘを絶縁体１０Ｘや端子金具９０Ｘに保持せずに、中心電極４０Ｘを端子金具９０Ｘに対して軸線方向に摺動可能に構成すると、中心電極４０Ｘが湾曲することを抑制でき、主体金具６０Ｘの内部でフラッシュオーバが発生することを抑制できる。しかしながら、この場合には、端子金具９０Ｘと中心電極４０Ｘとの接触性が低下して、接触抵抗が増大する。この結果、中心電極４０ＸとコネクタＣＴＸとの間の導電性が低下する。 In this case, in the igniter plug 100X, when the center electrode 40X is fixed to the terminal metal fitting 90X, the insulator 10X holds the terminal metal fitting 90X and the center electrode 40X. Then, when the center electrode 40X is extended due to thermal expansion, the center electrode 40X is curved. As a result, for example, the center electrode 40X may approach the main metal fitting 60X, and a flashover may occur. On the other hand, in order to suppress the curvature of the center electrode 40X, for example, the center electrode 40X can be slid in the axial direction with respect to the terminal metal fitting 90X without holding the center electrode 40X on the insulator 10X or the terminal metal fitting 90X. When configured, it is possible to suppress the bending of the center electrode 40X, and it is possible to suppress the occurrence of flashover inside the main metal fitting 60X. However, in this case, the contact property between the terminal fitting 90X and the center electrode 40X decreases, and the contact resistance increases. As a result, the conductivity between the center electrode 40X and the connector CTX is reduced.

これに対して本実施形態のイグナイタプラグ１００によれば、上述したように、中心電極４０は、コネクタＣＴと直接接触し、かつ、中心電極４０は、後端側絶縁体１０に遊嵌状に挿通されるので、比較形態のイグナイタプラグ１００Ｘのような不具合は発生しない。したがって、本実施形態のイグナイタプラグ１００では、コネクタＣＴと中心電極４０との間の導電性の向上と、熱膨張時の中心電極４０の湾曲の抑制と、を両立できる。 On the other hand, according to the igniter plug 100 of the present embodiment, as described above, the center electrode 40 is in direct contact with the connector CT, and the center electrode 40 is loosely fitted to the rear end side insulator 10. Since it is inserted, a problem like the igniter plug 100X in the comparative form does not occur. Therefore, in the igniter plug 100 of the present embodiment, it is possible to improve the conductivity between the connector CT and the center electrode 40 and suppress the bending of the center electrode 40 at the time of thermal expansion.

さらに、本実施形態のイグナイタプラグ１００は、中心電極４０は、発火部４２Ｃを含む第１部分（具体的には、先端部材４２）と、第１部分よりも比抵抗が小さな材料で形成される第２部分（具体的には、中央部材４３と後端部材４４）と、を有している。そして、第１部分と第２部分とは接合されてなる。この結果、コネクタＣＴと発火部４２Ｃを含む第１部分との間に位置する第２部分の抵抗を低減することができ、導電性をさらに向上できる。 Further, in the igniter plug 100 of the present embodiment, the center electrode 40 is formed of a first portion (specifically, a tip member 42) including an ignition portion 42C and a material having a resistivity smaller than that of the first portion. It has a second portion (specifically, a central member 43 and a rear end member 44). Then, the first portion and the second portion are joined. As a result, the resistance of the second portion located between the connector CT and the first portion including the ignition portion 42C can be reduced, and the conductivity can be further improved.

ここで、仮に、金属筒部材７０が配置されず、中心電極４０が後端側絶縁体１０に遊嵌状に挿通されているだけであると、イグナイタプラグに加わる振動等により中心電極４０が後端側絶縁体１０に接触して後端側絶縁体１０にクラックが発生するおそれがある。これに対し、本実施形態のイグナイタプラグ１００は、後端側絶縁体１０の軸孔１２の内部に固定された金属筒部材７０を備え、中心電極４０は、金属筒部材７０に遊嵌状に挿通されている。この結果、中心電極４０が後端側絶縁体１０に直接接触しないので、エンジンの振動などに起因して中心電極４０が振動した場合に、後端側絶縁体１０にクラックが発生することを抑制できる。その上、中心電極４０は金属筒部材７０に遊嵌状に挿通されているため、中心電極４０が熱膨張によって伸長した場合に湾曲することも抑制できる。 Here, if the metal cylinder member 70 is not arranged and the center electrode 40 is only loosely inserted into the rear end side insulator 10, the center electrode 40 is rearward due to vibration or the like applied to the igniter plug. There is a risk that the rear end side insulator 10 may come into contact with the end side insulator 10 and cracks may occur. On the other hand, the igniter plug 100 of the present embodiment includes a metal cylinder member 70 fixed inside the shaft hole 12 of the rear end side insulator 10, and the center electrode 40 is loosely fitted to the metal cylinder member 70. It has been inserted. As a result, since the center electrode 40 does not come into direct contact with the rear end side insulator 10, it is possible to prevent cracks from occurring in the rear end side insulator 10 when the center electrode 40 vibrates due to engine vibration or the like. can. Moreover, since the center electrode 40 is loosely inserted into the metal cylinder member 70, it is possible to prevent the center electrode 40 from bending when it is extended due to thermal expansion.

また、先端側絶縁体２０と後端側絶縁体１０とが軸線方向に離間して配置されているので、仮に、主体金具６０と中心電極４０とが空間のみを介して配置されると、主体金具６０の内部でフラッシュオーバが発生するおそれがある。これに対し、本実施形態のイグナイタプラグ１００は、主体金具６０の内部（貫通孔６９内）で、かつ、後端側絶縁体１０と先端側絶縁体２０との間に、絶縁粉末５が充填されている。この結果、中心電極４０と主体金具６０との間の絶縁性を確保して、主体金具６０の内部でのフラッシュオーバを抑制できる。さらには、中心電極４０が貫通孔６９内で振動することを抑制できる。この結果、例えば、先端側絶縁体２０や絶縁体１０の割れなどの不具合を抑制できる。 Further, since the front end side insulator 20 and the rear end side insulator 10 are arranged apart from each other in the axial direction, if the main metal fitting 60 and the center electrode 40 are arranged only through the space, the main body Flashover may occur inside the metal fitting 60. On the other hand, in the igniter plug 100 of the present embodiment, the insulating powder 5 is filled inside the main metal fitting 60 (inside the through hole 69) and between the rear end side insulator 10 and the front end side insulator 20. Has been done. As a result, the insulation between the center electrode 40 and the main metal fitting 60 can be ensured, and flashover inside the main metal fitting 60 can be suppressed. Further, it is possible to suppress the center electrode 40 from vibrating in the through hole 69. As a result, for example, defects such as cracking of the tip-side insulator 20 and the insulator 10 can be suppressed.

さらに、本実施形態のイグナイタプラグ１００は、後端側絶縁体１０と先端側絶縁体２０との間の軸線方向の範囲において、中心電極４０が挿通され、中心電極４０に固定された絶縁筒部材８０を備える。この結果、中心電極４０と主体金具６０との間の絶縁性をさらに確保して、例えば、先端側絶縁体２０と後端側絶縁体１０とが軸線方向に離間している位置において、主体金具６０の内部でのフラッシュオーバを抑制できる。 Further, in the igniter plug 100 of the present embodiment, the center electrode 40 is inserted in the range in the axial direction between the rear end side insulator 10 and the front end side insulator 20, and the insulating cylinder member is fixed to the center electrode 40. Equipped with 80. As a result, the insulating property between the center electrode 40 and the main metal fitting 60 is further secured, and for example, at a position where the front end side insulator 20 and the rear end side insulator 10 are separated from each other in the axial direction, the main metal fitting Flashover inside the 60 can be suppressed.

Ｂ．変形例
（１）上記イグナイタプラグ１００の具体的構成は、一例であり、これに限られない。例えば、間隙Ｇの近傍の構成は、一例であり、これに限られない。例えば、中心電極４０の先端は、図２では、接地電極５０の貫通孔５７内に位置しているが、中心電極４０の先端は、接地電極５０よりも後端側に位置していても良い。そして、例えば、接地電極５０の後端向き面５０ｂと、先端側絶縁体２０の先端面と、の間には、耐消耗性に優れた貴金属チップが配置されても良い。この場合には、該貴金属チップと、中心電極４０の先端面と、の間が、火花放電が生じる間隙Ｇになる。また、出口孔６０ｏ、５０ｏのいずれは、省略されても良い。 B. Modification Example (1) The specific configuration of the igniter plug 100 is an example, and the present invention is not limited to this. For example, the configuration in the vicinity of the gap G is an example, and is not limited to this. For example, the tip of the center electrode 40 is located in the through hole 57 of the ground electrode 50 in FIG. 2, but the tip of the center electrode 40 may be located on the rear end side of the ground electrode 50. .. Then, for example, a precious metal chip having excellent wear resistance may be arranged between the rear end facing surface 50b of the ground electrode 50 and the tip surface of the front end side insulator 20. In this case, the gap G between the noble metal chip and the tip surface of the center electrode 40 is where spark discharge occurs. Further, any of the outlet holes 60o and 50o may be omitted.

（２）また、エンジン等へ取り付けるための主体金具６０の構成は、適宜に変更され得る。例えば、主体金具６０において、座部６６よりも先端側にエンジン等へ取り付けるための雄ネジが形成されていても良い。 (2) Further, the configuration of the main metal fitting 60 for attaching to the engine or the like can be appropriately changed. For example, in the main metal fitting 60, a male screw for attaching to an engine or the like may be formed on the tip side of the seat portion 66.

（３）また、主体金具６０の貫通孔６９において、後端側絶縁体１０と、先端側絶縁体２０と、の間には、さらに、別体の中央絶縁体が配置されても良い。例えば、中央絶縁体は、絶縁体１０および先端側絶縁体２０とは離間して、貫通孔６９内に配置される略筒状の絶縁体である。中央絶縁体は、例えば、主体金具６０に固定される。中心電極４０は、中央絶縁体の軸孔に、遊嵌状に挿通される。この場合には、絶縁粉末５と絶縁筒部材８０との一方または両方を省略しても良い。中央絶縁体を設けることで、絶縁粉末５や絶縁筒部材８０を省略しても、中心電極４０と主体金具６０との間の絶縁性を確保してフラッシュオーバを抑制できる。 (3) Further, in the through hole 69 of the main metal fitting 60, a separate central insulator may be further arranged between the rear end side insulator 10 and the front end side insulator 20. For example, the central insulator is a substantially tubular insulator arranged in the through hole 69 apart from the insulator 10 and the distal end side insulator 20. The central insulator is fixed to, for example, the main metal fitting 60. The center electrode 40 is loosely inserted into the shaft hole of the central insulator. In this case, one or both of the insulating powder 5 and the insulating cylinder member 80 may be omitted. By providing the central insulator, even if the insulating powder 5 and the insulating cylinder member 80 are omitted, the insulating property between the center electrode 40 and the main metal fitting 60 can be ensured and flashover can be suppressed.

（４）中心電極４０は、溶接によって接合された３個の部材（先端部材４２、中央部材４３、後端部材４４）から構成されているが、２個の部材で構成されても良いし、１個の部材で構成されても良い。中心電極が２個の部材で構成される場合には、例えば、先端側の部材は、Ｎｉ合金などの耐熱性に優れた材料で形成され、後端側の部材は、純Ｎｉなどの導電性に優れた材料で形成されても良い。中心電極が１個の部材で構成される場合には、例えば、Ｎｉ合金などの耐熱性に優れた材料で形成されても良い。 (4) The center electrode 40 is composed of three members (tip member 42, center member 43, rear end member 44) joined by welding, but may be composed of two members. It may be composed of one member. When the center electrode is composed of two members, for example, the member on the front end side is formed of a material having excellent heat resistance such as Ni alloy, and the member on the rear end side is conductive such as pure Ni. It may be formed of an excellent material. When the center electrode is composed of one member, it may be formed of a material having excellent heat resistance such as Ni alloy.

（５）また、金属筒部材７０が省略され、中心電極４０は、後端側絶縁体１０の軸孔１２に直接挿通されても良い。この場合でも中心電極４０は、後端側絶縁体１０に遊嵌状に挿通される。 (5) Further, the metal cylinder member 70 may be omitted, and the center electrode 40 may be directly inserted into the shaft hole 12 of the rear end side insulator 10. Even in this case, the center electrode 40 is loosely inserted into the rear end side insulator 10.

（６）上記実施形態の各部材の材料は、例示であり、これに限られない。例えば、中心電極４０の全部または一部は、鉄、鉄とニッケルとの合金、ＳＵＳ３０４などのステンレスで形成されても良い。また、絶縁粉末５は、マグネシアに限らず、カルシア、アルミナなどの他の絶縁材料の粉末であっても良く、マグネシア、カルシア、アルミナなどの複数種類の絶縁材料の混合物であっても良い。 (6) The material of each member of the above embodiment is an example, and is not limited thereto. For example, all or part of the center electrode 40 may be made of iron, an alloy of iron and nickel, or stainless steel such as SUS304. Further, the insulating powder 5 is not limited to magnesia, and may be a powder of other insulating materials such as calcia and alumina, and may be a mixture of a plurality of types of insulating materials such as magnesia, calcia and alumina.

以上、本発明の実施形態および変形例について説明したが、本発明はこれらの実施形態および変形例になんら限定されるものではなく、その要旨を逸脱しない範囲内において種々の態様での実施が可能である。 Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to these embodiments and modifications, and can be implemented in various embodiments without departing from the gist thereof. Is.

１…絶縁体、２ａ、２ｂ…滑石、３…接着材、４…栓部材、５…絶縁粉末、６…線パッキン、７…アルミナ滑石、８…板パッキン、９Ｐ…ガラス粉末、９ａ…シール部材、９ｂ…シール部材、１０…後端側絶縁体、１２…軸孔、１３…第１部材、１４…第２部材、２０…先端側絶縁体、２２…軸孔、２２Ａ…大内径孔、２２Ｂ…小内径孔、２３…後端小径部、２４…中央大径部、２５…先端小径部、２５Ａ…先端部分、２６…段部、４０…中心電極、４２…先端部材、４２Ａ…棒状部、４２Ｂ…鍔部、４２Ｃ…発火部、４３…中央部材、４４…後端部材、４６…コネクタ接触部、５０…接地電極、５０ｂ…後端向き面、５０ｏ…出口孔、５７…貫通孔、６０…主体金具、６０ｉ…入口孔、６０ｏ…出口孔、６１…後端金具、６２…中間金具、６２Ａ…貫通孔、６３…先端金具、６４…ネジ部、６５…工具係合部、６６、６７…座部、６８…小外径部、６９…貫通孔、７０…金属筒部材、７１…筒状部、７１…筒状部、７５…鍔部、８０…絶縁筒部材、１００…イグナイタプラグ、１３１…大外径部、１３２…小外径部、１３３…薄肉部、１４１…大外径部、１４２…小外径部、１４３…薄肉部、２００…組付治具、２１０…台部、２２０…大径部、２３０…小径部、２４０…棒部材、Ｇ…間隙、ＦＤ…先端方向、ＢＤ…後端方向、ＣＴ…コネクタ、ＡＸ…軸線、ＷＰ１、ＷＰ２…溶接部、ＳＰ１…筒状空間 1 ... insulator, 2a, 2b ... talc, 3 ... adhesive, 4 ... plug member, 5 ... insulating powder, 6 ... wire packing, 7 ... alumina talc, 8 ... plate packing, 9P ... glass powder, 9a ... sealing member , 9b ... Seal member, 10 ... Rear end side insulator, 12 ... Shaft hole, 13 ... First member, 14 ... Second member, 20 ... Tip side insulator, 22 ... Shaft hole, 22A ... Large inner diameter hole, 22B ... Small inner diameter hole, 23 ... Rear end small diameter part, 24 ... Central large diameter part, 25 ... Tip small diameter part, 25A ... Tip part, 26 ... Step part, 40 ... Center electrode, 42 ... Tip member, 42A ... Rod-shaped part, 42B ... flange part, 42C ... ignition part, 43 ... central member, 44 ... rear end member, 46 ... connector contact part, 50 ... ground electrode, 50b ... rear end facing surface, 50o ... outlet hole, 57 ... through hole, 60 ... Main metal fitting, 60i ... Inlet hole, 60o ... Exit hole, 61 ... Rear end metal fitting, 62 ... Intermediate metal fitting, 62A ... Through hole, 63 ... Tip metal fitting, 64 ... Screw part, 65 ... Tool engaging part, 66, 67 ... Seat part, 68 ... Small outer diameter part, 69 ... Through hole, 70 ... Metal cylinder member, 71 ... Cylindrical part, 71 ... Cylindrical part, 75 ... Flange part, 80 ... Insulated cylinder member, 100 ... Igniter plug, 131 ... Large outer diameter part, 132 ... Small outer diameter part 133 ... Thin wall part, 141 ... Large outer diameter part, 142 ... Small outer diameter part, 143 ... Thin wall part, 200 ... Assembly jig, 210 ... Base part, 220 ... Large diameter part, 230 ... Small diameter part, 240 ... Rod member, G ... Gap, FD ... Tip direction, BD ... Rear end direction, CT ... Connector, AX ... Axis line, WP1, WP2 ... Welded part, SP1 ... Cylindrical space

Claims

A rod-shaped center electrode that extends along the axis and has an ignition part on the tip side,
A tubular insulator that extends along the axis and is inserted with the center electrode.
A main metal fitting arranged on the outer periphery of the insulator and to which the insulator is fixed,
With
The insulator is an igniter plug having a tip-side insulator and a rear-end side insulator located on the rear end side of the tip-side insulator and separated from the tip-side insulator in the axial direction.
The rear end portion of the rear end side insulator is a connector accommodating portion for internally accommodating a connector for electrically connecting the center electrode and the power supply, and the rear end portion is opened toward the rear end side. It has a connector accommodating portion having a shaft hole whose diameter is larger than that of the shaft hole at the tip of the end side insulator.
The center electrode extends from the tip end portion of the front end side insulator to the rear end portion of the rear end side insulator, and has a connector contact portion that directly contacts the connector at the rear end portion of the center electrode.
The center electrode is loosely fitted through the rear end side insulator while being supported by the front end side insulator.
The igniter plug, wherein the connector contact portion is arranged inside the connector accommodating portion.

The igniter plug according to claim 1.
The center electrode has a first portion including the ignition portion and a second portion formed of a material having a specific resistivity smaller than that of the first portion and provided on the rear end side of the first portion.
An igniter plug characterized in that the first portion and the second portion are joined to each other.

The igniter plug according to claim 1 or 2, further
A metal tubular member fixed inside the shaft hole of the rear end side insulator is provided.
The igniter plug is characterized in that the center electrode is loosely inserted into the tubular member.

The igniter plug according to any one of claims 1 to 3, further
An igniter plug comprising an insulating powder that is at least filled inside the main metal fitting and between the rear end side insulator and the front end side insulator.

The igniter plug according to any one of claims 1 to 4, further
An insulating tubular member through which the center electrode is inserted and fixed to the center electrode is provided in at least a part of the axial range between the rear end side insulator and the front end side insulator. The characteristic igniter plug.