JP2004146126A

JP2004146126A - Plug cap and manufacturing method of the same

Info

Publication number: JP2004146126A
Application number: JP2002307558A
Authority: JP
Inventors: Shigemi Ishihara; 石原　茂巳; Osamu Kato; 加藤　修
Original assignee: NGK Spark Plug Co Ltd
Current assignee: Niterra Co Ltd
Priority date: 2002-10-22
Filing date: 2002-10-22
Publication date: 2004-05-20
Anticipated expiration: 2022-10-22
Also published as: CN2658981Y; JP4130350B2; BR0304612A

Abstract

<P>PROBLEM TO BE SOLVED: To effectively manufacture a plug cap with a screw terminal for connecting a cord having strong mounting strength without relying on insertion and without using a relaying lead wire. <P>SOLUTION: A hole 16 with a small diameter of which the inner diameter is made smaller than that of a part near to an opening end 14 is formed at the inner part of a cord side hollow hole 13 of a plug cap body 1 so as to communicate with the cord side hollow hole 13. The head 22 of the screw terminal 21 for connecting a cord is pressed in and mounted to the hole 16 with the small diameter of the plug cap body 1 while the plug cap body is not solidified yet by molding, with its head of a screw 23 made to face outward. The tip of the head 22 is made to protrude into the plug side hollow hole 13. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、プラグキャップに関し、詳しくはガソリンエンジンの点火プラグの端子（ターミナル）をキャップするためのプラグキャップに関する。
【０００２】
【従来の技術】
従来のプラグキャップとしては、図１０に示したものが知られている。このプラグキャップ２０１は、その本体２０２が合成樹脂（例えばフェノール樹脂）からなり、点火プラグの端子（図示せず）を覆うプラグ側空孔形成筒部２０５の上方に、分岐する形のコード側空孔形成筒部２１５を備えている。このものは、コード側空孔形成筒部２１５内の空孔２１３の奥所（本体樹脂内）に、頭部付きのネジ部材からなるコード接続用ネジ端子（単にネジ端子ともいう）２２１がその頭部（拡径部）２２２をインサートすることによって取付けられている。そして、ネジ端子２２１の頭部２２２の先端には中継リード２５１の一端部が接続されており、その他端部をプラグ側空孔形成筒部２０５の空孔奥所に露出させた形でインサートにより取付けられている。このようなプラグキャップ２０１においては、そのプラグ側空孔２０３内に、下端部の開口からコイルスプリング４１及び抵抗体４２を順次挿入し、外周面にネジの設けられたプラグコネクタ４５を同空孔内にネジ込み、コイルスプリング４１を圧縮し、中継リード線２５１の他端部に圧接させることで導通を保持するようになっている。このような構造のプラグキャップ２０１においては、コード接続用ネジ端子２２１の頭部２２２が、インサートされて本体２０２内に固定されているため、プラグコードのネジ込み接続時や引き抜きに対する固定力が高いといったメリットがある。
【０００３】
【発明が解決しようとする課題】
しかし、プラグキャップ本体２０２を製造するに当っては、次のような問題があった。すなわち、上記構造のものは、コード接続用ネジ端子２２１と中継リード２５１との２部品からなるインサートによるものであることから、本体２０２の成形に先立って、ネジ端子２２１の頭部２２２にカシメなどによって中継リード線２５１の一端部を固定したインサート部品を組立てておかないといけない。このように、上記の構造のプラグキャップ２０１では、コード接続用ネジ端子と中継リード線との組立を要するといった問題があった。
【０００４】
しかも、上記構造のような本体２０２を成形をするためには、その成形の都度、インサート部品（ネジ端子）を、インサート用保持型（孔付きのコアピン）内にセットする工程と、このセット状態のものを成形金型内に配置する工程とがそれぞれ必要となり、その成形工程が複雑化していたといった問題があった。
【０００５】
さらに、このようなインサート成形をするためには、そのインサート部品の金型内での安定的な保持、位置決めのため、型の開閉が上下になされる縦型射出成形機によらざるを得ない。一方、このような縦型射出成形機では、横型射出成形機に使用される金型の場合のように成形取り数を多数に設定することができない。このため、製造効率ないし生産性が悪く、コストの低減が図られないといった問題もあった。
【０００６】
本発明は、このような問題点に鑑みて成されたもので、その目的とするところは、インサートによることなく、しかも中継リード線を要することなく、取付け強度の高いコード接続用ネジ端子付きのプラグキャップを効率的に製造できるようにすることにある。
【０００７】
【課題を解決するための手段】
前記の課題を解決するため、請求項１に記載の発明は、点火プラグの端子接続用のプラグコネクタが取付けられるプラグ側空孔と、プラグコードの雌ネジ端子をネジ込み方式によって接続するコード接続用ネジ端子が取付けられるコード側空孔とを備えた樹脂成形品からなるプラグキャップ本体と、前記コード側空孔に取付けられた前記コード接続用ネジ端子とを含んでなるプラグキャップであって、
前記プラグキャップ本体は、前記コード側空孔の開口端から見た奥所に、内径を該開口端寄り部位の内径より小径とした小径孔部を前記プラグ側空孔に連通するように備えており、
前記コード接続用ネジ端子は頭部付きのネジ部材からなり、そのネジの先端を前記開口端側にして該頭部を、成形されて固化（硬化）する前のプラグキャップ本体の前記小径孔部に圧入して取付けるとともに、該頭部の先端を前記プラグ側空孔に露出させてなることを特徴とする。本明細書において、コード接続用ネジ端子（ネジ部材）の頭部の先端とは、頭部のうち、ネジの先端から離間する方向の端をいう。
【０００８】
上記の構成の本発明のプラグキャップは、従来のように、インサートによることなく、コード接続用ネジ端子の頭部を、成形されて固化（収縮）する前のプラグキャップ本体の前記小径孔部に圧入して取付けたものである。したがって、コード接続用ネジ端子は、頭部を介して、樹脂の固化に伴う収縮によって強固に取付けられる。しかも、固化、収縮する前の圧入のため、その圧入も容易であるため、コード接続用ネジ端子付きのプラグキャップを効率良く製造できる。すなわち、本発明のプラグキャップによれば、インサートによらないため、インサート部品の保持型が不要となるし、横型射出成形機によって製造できるため、成形型における成形取り数を増やせることから、プラグキャップの低コスト化が図られる。さらに、頭部の先端はプラグ側空孔に露出しており、したがって、コード接続用ネジ端子と、プラグコネクタ側との導通は従来と同様に、スプリングコイル等により容易に保持できる。
【０００９】
請求項１のプラグキャップにおいては、請求項２に記載のように、前記頭部のうちの前記小径孔部内に位置すべき部位の外周面が、該頭部が前記小径孔部に圧入されて取付けられた状態において、前記コード接続用ネジ端子が前記開口端側に引張られた際及び前記コード接続用ネジ端子の軸線回りにねじられた際に、該頭部のうちの外周面を包囲する樹脂によって抜け止め及び回り止めをなす形状に形成されているとよい。これにより、プラグキャップにプラグコードを確実に取付け、導通することができる。
【００１０】
具体的には、請求項１のプラグキャップにおいて、請求項３に記載のように、前記頭部のうちの前記小径孔部内に位置すべき部位の外径が、ネジの先端寄り部位を小径とし、該頭部の先端寄り部位を大径とし、その大径をなす該頭部の先端寄り部位の外周面に、軸線方向に沿って延びる多数の筋目状の凹凸部が形成されているものである。このものでは、該頭部のうちの外周面を包囲する樹脂が、該凹凸部の表面、及び小径をなす、ネジの先端寄り部位の外周面に密着することから、抜け止め及び回り止めをなすことになる。
【００１１】
そして、請求項１〜３のいずれのプラグキャップにおいても、請求項４に記載のように、前記プラグ側空孔の軸と前記コード接続用ネジ端子の軸が交差しているプラグキャップにおいて、前記頭部が圧入される前記小径孔部の内周面が、前記プラグ側空孔を形成するプラグ側空孔形成筒部の筒壁を形成する部位に存在するものであるとよい。これにより、コード接続用ネジ端子を確実に固定することができる。
【００１２】
そして、請求項１〜４のいずれのプラグキャップにおいても、請求項５に記載のように、前記頭部は、前記小径孔部に圧入された際、該頭部の先端が前記プラグ側空孔に突出されているとよい。これにより、コード接続用ネジ端子と、プラグコネクタ側との導通をより確実にできる。
【００１３】
請求項６に記載の発明は、点火プラグの端子接続用のプラグコネクタが取付けられるプラグ側空孔と、プラグコードの雌ネジ端子をネジ込み方式によって接続するコード接続用ネジ端子が取付けられるコード側空孔とを備えた樹脂成形品からなるプラグキャップ本体と、前記コード側空孔に取付けられた前記コード接続用ネジ端子とを含んでなるプラグキャップの製造方法であって、
前記プラグキャップ本体は、前記コード側空孔の開口端から見た奥所に、内径を該開口端寄り部位の内径より小径とした小径孔部を前記プラグ側空孔に連通するように備えたものとしておく一方、
前記コード接続用ネジ端子は頭部付きのネジ部材としておき、そのネジの先端を前記開口端側にして該頭部を、成形されて固化する前のプラグキャップ本体の前記小径孔部に圧入するとともに、該頭部の先端を前記プラグ側空孔に露出させ、その後の固化に伴う該プラグキャップ本体の樹脂の収縮によって前記頭部を締付けて取り付けることを特徴とするプラグキャップの製造方法である。
【００１４】
【発明の実施の形態】
さて次に、このようなプラグキャップの実施の形態について、図１〜図５に基づいて詳細に説明する。図中１は、プラグキャップ１０１をなす熱硬化性樹脂（例えばフェノール樹脂）からなるプラグキャップ本体（以下、キャップ本体又は単に本体ともいう）である。この本体１は、点火プラグ（図示せず）の端子接続用のプラグコネクタが取付けられるプラグ側空孔３を有するプラグ側空孔形成筒部５と、プラグコード接続用のコード接続用ネジ端子２１が取付けられるコード側空孔１３を有するコード側空孔形成筒部１５を主体として構成されている。
【００１５】
このうち、プラグ側空孔形成筒部５は、その中央軸線Ｇｌに対し、断面円形で外径が大径をなす大径直管部６と、テーパ部７を介して連なる、縮径された小径直管部８を備えている。プラグ側空孔３は、プラグ側空孔形成筒部５の内側に軸線Ｇｌに同心状で断面円形に形成されている。ただし、プラグ側空孔３は、プラグ側空孔形成筒部５の開口端（下端）寄り部位の大径空孔３ａから、それよりやや小径のネジ（雌ネジ）部４を介し、奥所はさらに小径の小径空孔３ｂとされている。
【００１６】
一方、コード側空孔形成筒部１５は、本形態では、断面円形で同一外径をなし、プラグ側空孔形成筒部５の上端寄り部位から、斜めに突出状に形成されている。ただし、コード側空孔形成筒部１５の中央軸線Ｇ２と、プラグ側空孔形成筒部５の中央軸線Ｇｌとは正面視、その交差角θが、例えば１２０度となるように形成されている。そして、コード側空孔１３は、コード側空孔形成筒部１５の内側に軸線Ｇ２と同心状で断面円形の空孔１３ａをなしており、その開口端１４から見た奥所には、内径をその開口端１４寄り部位より小径とした断面円形の小径孔部１６を備えている（図２参照）。この小径孔部１６は、プラグ側空孔３を形成するプラグ側空孔形成筒部５の筒壁８ａに対応する部位をも含めて存在し、プラグ側空孔３の奥所に連通している。これにより、本形態では、コード側空孔１３とプラグ側空孔３の両空孔が、１２０度で屈曲状をなして連通している。なお、プラグ側空孔形成筒部５の下端部の外周面には円形のフランジ６ａがプラグキャップ１０１の半径方向に突出状に形成され、上端部には、先端に拡径ボス部を有する軸状の把持部９が軸線方向に突出状に形成されている。
【００１７】
一方、コード側空孔１３内には、頭部２２付きのネジ部材からなるコード接続用ネジ端子２１が、その先端のネジ２３を空孔１３ａに配置するように取付けられている。本形態においてこのコード接続用ネジ端子２１の頭部２２は、図２に示すように、そのネジ２３の軸線Ｇ３に沿い断面円形の軸状をなして延びている。ただし、頭部２２のうちの先端寄り部位は同心状で細めの円軸部２５とされ、それよりネジ２３寄り部位（先端寄り部位）２６は全体が相対的に太めに形成され、小径孔部１６内に位置すべき部位とされている。このようなコード接続用ネジ端子２１付きのプラグキャップ１０１は、プラグキャップ本体１を射出成形した脱型直後に、その樹脂の固化前（保形性のある軟質状態）において、コード側形成筒部１５の開口端１４側から、ネジ端子２１をその頭部２２側から小径孔部１６内に押込んで圧入（熱間圧入）して製造されたものである（図２参照）。なお、圧入は、本形態のフェノール樹脂製のものでは脱型後６０秒以内に行うのが好ましく、その後は自然冷却すればよい。ただし、本形態では圧入後、頭部２２の先端をなす円軸部２５がプラグ側空孔３に突出しており、後述するように、その突出部に、圧入後の工程でプラグ側空孔３内に挿入されるスプリングが押し付けられるように構成されている。
【００１８】
本形態において、このようなコード接続用ネジ端子２１は、例えば黄銅からなり、頭部２２のうちの小径孔部１６内に圧入されて位置すべき部位（以下、圧入部位ともいう）２６の外径は、略その全体が圧入前の小径孔部１６の内径より大きめに設定されている。この圧入部位２６は、ネジ２３寄り部位が相対的に小径の小径軸部２７とされ、それより頭部２２の先端（円軸部２５の先端）寄り部位が相対的に大径の大径軸部２８とされている。ただし、小径軸部２７のネジ２３寄り端には軸線Ｇ３回りに突出する円形フランジ２９が形成されており、これが圧入時におけるストッパーをなすようにされている。また、頭部２２のうちの小径孔部１６内に位置すべき圧入部位２６の大径軸部２８、つまり圧入部位２６の先端寄り部位の外周面には、軸線Ｇ３方向に沿って延びる多数の筋目状の凹凸部（本例ではローレット切りによる筋目）が形成されている。なお、頭部２２の小径軸部２７の外径は筋目状の凹凸部の谷底（凹溝底）の径と同じとされている。また、頭部２２の先端の円軸部２５の外径は、圧入前の小径孔部１６の内径より小さく設定されている。
【００１９】
このように本体１の固化前にネジ端子２１を熱間圧入によって取付けてなるプラグキャップ１０１においては、圧入後の樹脂の固化過程で、小径孔部１６の内周面をなす樹脂が同孔の半径方向に収縮し、頭部２２の圧入部位２６の外周面に締付ける形となって密着する（図３、４参照）。すなわち、その樹脂が大径軸部２８の外周面の凹凸部間の谷（凹部）に入り込むとともに、頭部２２の小径軸部２７の外周面にも密着する。なお、本形態においてネジ端子２１の頭部２２に設けられたフランジ２９は、圧入時のストッパをなすため、圧入における位置決め精度を高めることができる。
【００２０】
しかして、このようなプラグキャップ１０１は、その後、図５に示したように、プラグ側空孔３に、その下端部の開口から、コイルスプリング４１、及び抵抗体４２を順次挿入し、内周面のネジ部４に、外周面にネジ４４の形成された有底円筒状のプラグコネクタ４５をネジ込む。こうすることで、コイルスプリング４１は圧縮され、その上端部が、プラグ側空孔３の奥所に突出しているコード接続用ネジ端子２１の円軸部２５に押し付けられて導通が保持される。
【００２１】
さて次ぎに、このような本形態のプラグキャップ１０１の効果について説明する。本プラグキャップは、コード接続用ネジ端子２１の取付けを、中継リード線を用いた組立体をインサート成形するものでないため、そのプラグキャップ本体１は横型射出成形機によって容易に製造できる。このため、同一型面でも、プラグキャップ本体１の成形取り数を増やすことができる。そして、コード接続用ネジ端子２１の取付けは、上記したように本体１の成形直後の樹脂の固化前に熱間圧入によるものであることから、容易に行うことができる。したがって、コード接続用ネジ端子２１付きのプラグキャップのコストの低減が図られる。
【００２２】
また、本形態のプラグキャップ１０１においては、取付けられたネジ端子２１はその頭部２２の大径軸部２８の外周面の筋目状の凹凸部間の谷（凹部）に樹脂が入り込んでいる（図３、４参照）。したがって、コード接続用ネジ端子２１に、プラグコードの雌ネジ端子をネジ込み接続する場合などにおいて、大きな回転力（ねじりトルク）Ｔが働いても、大径軸部２８の外周面の凹部に入り込んだ樹脂が回り止め作用をするから、ネジ端子２１が弛緩したり外れたりすることが有効に防止される。そして、このような筋目状の凹凸部は、圧入時には、小径孔部１６の内周面を切り込む形となるため、円滑な圧入も得られる。なお、圧入前（固化前）の小径孔部１６の内径は、適切な圧入代となるように、頭部２２をなす大径軸部２８の凹凸部の凹部（谷底）の径と略同一に設定しておくとよい。
【００２３】
そして、本形態では、ネジ端子２１の軸線Ｇ３に沿って開口端側（外方）に大きな引張り力Ｐが作用する場合においても、頭部２６を包囲する樹脂が先端のネジ２３寄りの小径軸部２７の表面に接しているため、これが抜け止め作用をする。このように、本形態ではコード接続用ネジ端子２１の取付け強度に格別高い信頼性が得られる。なお、頭部２２におけるこのような小径軸部２７の外径は、小径孔部１６の内径と略同一ないし若干大きめに設定しておくとよい。
【００２４】
また、本形態のプラグキャップにおいては次のような効果もある。すなわち、頭部２２の小径孔部１６への圧入により、小径孔部１６はその半径外方に外力を受ける。このため、仮に、小径孔部が、図２中の２点鎖線部位１１６に示したように、プラグ側空孔３を形成するプラグ側空孔形成筒部５の筒壁８ａの外面より突出する部位のコード側空孔形成筒部１５内に位置する場合には、頭部２２の圧入、及び樹脂の収縮によって、コード側空孔形成筒部１５の筒壁が半径方向に膨らむ形に変形する。このため圧入代によっては、圧入部位の亀裂、ワレ等の問題を発生させるおそれがある。しかし、本形態では、頭部２２が圧入される小径孔部１６の内周面が、プラグ側空孔３を形成するプラグ側空孔形成筒部５の筒壁８ａに対応する部位にわたって存在しているため、そのような問題の発生を有効に防止できる。とくに、本形態では、頭部２２のうちの大径軸部２８の略全体が、プラグ側空孔形成筒部５の筒壁８ａに対応する小径孔部１６内に位置しているため、その効果が大きい。
【００２５】
なお、本形態では、コード接続用ネジ端子２１の頭部２２の先端において突出する円軸部２５をプラグ側空孔３内に突出させているため、圧入後の工程でセットされるコイルスプリング４１は、真直ぐに圧縮されて押し付けられるから導通の信頼性を損なうこともない。円軸部２５は、その先端寄り部位を図３中２点鎖線で示したように、先細りテーパ状に形成してもよい。
【００２６】
因みに、本形態のプラグキャップ１０１をなすその本体１の射出成形においては、インサートもないことから横型射出成形（機）によって成形できるが、このときは、図６に示したような割り面（Ｐ　Ｌ）をもつ左右の成形型（固定盤９１、可動盤９２）としておくとよい。なお、このように成形する場合には、プラグ側空孔形成筒部５の内部に対応するコア（プラグコネクタのネジ込み部をなすネジ部を含む空孔に対応するコア）９５が必要になる。このため、金型から取り出されたキャップ本体１には、そのネジ付きコア９５が嵌った状態にあることから、コード接続用ネジ端子２１の圧入に際しては、成形直後にこれを螺退し、少なくとも、プラグ側空孔３をなす奥所に、ネジ端子の頭部先端が入り込めるように空所を存在させておく。
【００２７】
本発明のプラグキャップは、上記の実施形態のものに限定されるものではなく、その要旨を逸脱しない範囲において、適宜に設計変更して具体化できる。例えば、コード接続用ネジ端子については、図７、８に示したような形状に変更してもよい。ただし、本形態のコード接続用ネジ端子５１は前記形態とその頭部２２のうち、小径孔部１６内に位置すべき部位の形状のみが異なるだけであるから、その相違点のみ説明し、同一又は対応する部位には同一の符号を付すに止める。
【００２８】
すなわち、本形態におけるコード接続用ネジ端子５１は、頭部２２のうちの小径孔部内に位置すべき部位２６を、頭部先端の円軸部２５より大径の円柱状軸部５７とした一方、その円柱状軸部５７のうちの、ネジ２３寄り部位に、軸線Ｇ３を挟んで平行な２つの平面５５による凹部（二面取り）を設けたものである。なお、前記形態におけるコード接続用ネジ端子２１では、その頭部２２のネジ２３寄り端にフランジ２９を設けたものとしたが、本形態では、このようなフランジはない。しかして、その頭部２２に筋目状の凹凸部を設けていないが、頭部２２の二面取り部をなす平面５５の部位が凹部をなしている。このため、コード接続用ネジ端子５１を、その頭部２２の円柱状軸部５７を小径孔部１６内に、その樹脂の固化前に圧入して位置させたときには、その二面取り部をなす平面５５に、本体１の小径孔部１６の内周面をなす樹脂がその固化に伴う収縮により密着する。これにより、コード接続用ネジ端子５１の回り止め及び抜け止めが図られる。
【００２９】
前記したコード接続用ネジ端子５１より理解されるが、回り止め及び抜け止めをさせるための手段としては、前記形態のネジ端子５１の様に、頭部２２に筋目状の凹凸部を設けることに限られるものではない。コード接続用ネジ端子の頭部の断面（軸線に垂直断面）を四角形などの多角形としてもよい。また、筋目状の凹凸部に代えて、網目状の凹凸を付けてもよい。
【００３０】
図９は、コード接続用ネジ端子６１の他の実施例を示したものである。このものは、頭部６２が略同一径の円軸状をなし、その先端が先細りテーパ状に形成されている。そして、テーパー形状を除く頭部６２の一部の部位が所定の幅で他の部位より若干大径の大径軸部６８とされ、その他の部位が小径軸部６７とされている。そして、この大径軸部６８の外周面に、軸線方向に沿って延びる多数の筋目状の凹凸部が形成されている。このようなコード接続用ネジ端子は、図９に示したように、頭部６２のうち、中間の大径軸部６８を含むネジ２３寄り部位が小径孔部１６に圧入して取付けられるものであり、したがって、図１の実施形態のものと同様の効果が得られる。
【００３１】
上記した各実施の形態において、コード接続用ネジ端子はその頭部が、小径孔部に圧入された状態において、その外周面を包囲する樹脂によって抜け止め及び回り止めをなす形状に形成されている。しかし、本発明では、頭部付きのネジ部材であり、その頭部の外周面に密着する樹脂によって、ネジ端子の外方への引張りや回転トルクに耐え得、プラグコードの雌ネジ端子をネジ込み方式によって接続できるものであればよく、必ずしもこのように形成されている必要はない。また、ネジ端子の頭部は、プラグ側空孔に内挿されるコイルスプリングとの導通保持ができればよく、したがって、頭部の先端がプラグ側空孔側に突出していなくとも、単に露出しているだけでもよい。
【００３２】
そして、プラグキャップは、前記形態ではプラグ側空孔と、コード側空孔との各軸線が１２０度で交差するものにおいて具体化したが、その角度は任意のものにおいて具体化できることはいうまでもない。また、本体の材質は、熱硬化性樹脂に限定されるものでないし、ネジ端子についても適宜の金属材から形成すればよい。
【００３３】
【発明の効果】
本発明においては、インサートによることなく、しかも中継リード線を要することなく、取付け強度の高いコード接続用ネジ端子付きのプラグキャップを効率的に製造できる。すなわち、コード接続用ネジ端子をその頭部を圧入して取り付ける構造としたため、部品点数の減少、構造、工程の簡素化が図られ、製造コストの大幅な低減が期待される。
【図面の簡単な説明】
【図１】本発明に係るプラグキャップの実施形態例を示す破断正面図。
【図２】図１のプラグキャップをなす圧入前の本体及びコード接続用ネジ端子を示す図。
【図３】図１のプラグキャップにおけるコード接続用ネジ端子部分の説明用拡大図。
【図４】図３のＡ−Ａ線拡大断面図。
【図５】図１のプラグキャップに抵抗体等を組み込んだ破断正面図。
【図６】図１のプラグキャップ本体を成形する成形型の説明用断面図。
【図７】コード接続用ネジ端子の別形態を説明する図。
【図８】図８におけるＢ−Ｂ線断面。
【図９】コード接続用ネジ端子の別形態を説明する図。
【図１０】従来のプラグキャップの正面断面図。
【符号の説明】
１　プラグキャップ本体
２、６２　記コード接続用ネジ端子の頭部
３　プラグ側空孔
１３　コード側空孔
１４　コード側空孔の開口端
１６　小径孔部
２１、５１、６１　コード接続用ネジ端子（ネジ部材）
２３　ネジの先端
４５　プラグコネクタ
１０１　プラグキャップ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plug cap, and more particularly, to a plug cap for capping a terminal of a spark plug of a gasoline engine.
[0002]
[Prior art]
As a conventional plug cap, the one shown in FIG. 10 is known. The plug cap 201 has a main body 202 made of a synthetic resin (for example, phenol resin), and has a branched cord-side space above a plug-side hole forming cylinder 205 covering a terminal (not shown) of the ignition plug. A hole forming cylinder 215 is provided. In this case, a cord connecting screw terminal (simply referred to as a screw terminal) 221 formed of a screw member with a head is provided at a depth (in the main body resin) of the hole 213 in the cord side hole forming cylindrical portion 215. It is attached by inserting a head (expanded portion) 222. One end of the relay lead 251 is connected to the tip of the head 222 of the screw terminal 221, and the other end is exposed to the inside of the hole of the plug-side hole forming cylinder 205 by insert. Installed. In such a plug cap 201, the coil spring 41 and the resistor 42 are sequentially inserted into the plug-side hole 203 from the opening at the lower end, and the plug connector 45 provided with a screw on the outer peripheral surface is connected to the hole. Then, the coil spring 41 is compressed, and is brought into pressure contact with the other end of the relay lead wire 251 to maintain conduction. In the plug cap 201 having such a structure, the head 222 of the cord connection screw terminal 221 is inserted and fixed in the main body 202, so that the plug cord has a high fixing force at the time of screw connection and pulling out. There is such a merit.
[0003]
[Problems to be solved by the invention]
However, manufacturing the plug cap body 202 has the following problems. That is, since the above-mentioned structure is based on an insert consisting of two parts, the cord connection screw terminal 221 and the relay lead 251, the head terminal 222 of the screw terminal 221 is caulked before forming the main body 202. It is necessary to assemble an insert part to which one end of the relay lead wire 251 is fixed. As described above, the plug cap 201 having the above-described structure has a problem that the screw terminal for cord connection and the relay lead wire need to be assembled.
[0004]
In addition, in order to form the main body 202 having the above structure, a step of setting an insert part (screw terminal) in a holding die for insert (core pin with a hole) every time the molding is performed, And a step of arranging them in a molding die is required, and there has been a problem that the molding step is complicated.
[0005]
Furthermore, in order to perform such insert molding, a vertical injection molding machine in which the mold is opened and closed up and down in order to stably hold and position the insert part in the mold must be used. . On the other hand, in such a vertical injection molding machine, it is not possible to set a large number of moldings as in the case of a mold used in a horizontal injection molding machine. For this reason, there has been a problem that manufacturing efficiency or productivity is poor, and cost cannot be reduced.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object thereof is to provide a high-strength cord connecting screw terminal without using an insert, and without requiring a relay lead wire. It is to enable efficient manufacture of a plug cap.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is a cord connection in which a plug side hole to which a plug connector for connecting a terminal of an ignition plug is attached and a female screw terminal of a plug cord are connected by a screwing method. A plug cap body comprising a resin molded product having a cord-side hole to which the screw terminal is attached, and a plug cap including the cord connection screw terminal attached to the cord-side hole,
The plug cap body is provided with a small-diameter hole portion having an inner diameter smaller than the inner diameter of a portion near the opening end, communicating with the plug-side hole, at a depth viewed from the opening end of the cord-side hole. Yes,
The cord connection screw terminal is formed of a screw member with a head, and the small-diameter hole portion of the plug cap body before the head is formed and solidified (hardened) with the tip of the screw being the opening end side. And the head is exposed by exposing the tip of the head to the plug-side hole. In this specification, the tip of the head of the cord connection screw terminal (screw member) refers to the end of the head in the direction away from the tip of the screw.
[0008]
In the plug cap of the present invention having the above-described configuration, the head of the screw terminal for cord connection is formed in the small-diameter hole portion of the plug cap main body before being molded and solidified (shrinked) without using an insert as in the related art. It was mounted by press fitting. Therefore, the screw terminal for cord connection is firmly attached via the head by shrinkage accompanying the solidification of the resin. Moreover, since the press-fitting before the solidification and shrinkage is performed, the press-fitting is easy, so that a plug cap with a screw terminal for cord connection can be efficiently manufactured. That is, according to the plug cap of the present invention, since the insert is not used, a holding die for the insert component is not required, and the plug cap can be manufactured by the horizontal injection molding machine, so that the number of moldings in the molding die can be increased. Cost is reduced. Furthermore, the tip of the head is exposed in the plug-side hole, so that conduction between the cord connection screw terminal and the plug connector side can be easily held by a spring coil or the like as in the conventional case.
[0009]
In the plug cap of the first aspect, as described in the second aspect, the outer peripheral surface of a portion of the head that should be located in the small-diameter hole has the head press-fitted into the small-diameter hole. In the attached state, when the cord connection screw terminal is pulled toward the opening end and when it is twisted around the axis of the cord connection screw terminal, it surrounds the outer peripheral surface of the head. It is preferable that the resin is formed in a shape that prevents the rotation and the rotation. Thereby, the plug cord can be securely attached to the plug cap and can be electrically connected.
[0010]
Specifically, in the plug cap of the first aspect, as described in the third aspect, the outer diameter of a portion of the head that should be located in the small-diameter hole portion has a small diameter at a portion near the tip of the screw. A large-diameter portion of the head near the tip, and a large number of stripe-shaped uneven portions extending along the axial direction are formed on the outer peripheral surface of the portion near the tip of the head that forms the large diameter. is there. In this device, the resin surrounding the outer peripheral surface of the head is in close contact with the surface of the uneven portion and the outer peripheral surface of the small-diameter portion near the tip of the screw, thereby preventing the head from coming off and rotating. Will be.
[0011]
In any of the plug caps according to claims 1 to 3, the plug cap in which the axis of the plug-side hole intersects the axis of the screw terminal for cord connection as described in claim 4, Preferably, the inner peripheral surface of the small-diameter hole into which the head is press-fitted is present at a portion forming a cylindrical wall of the plug-side hole forming cylindrical portion forming the plug-side hole. Thereby, the screw terminal for cord connection can be securely fixed.
[0012]
In any of the plug caps according to claims 1 to 4, as described in claim 5, when the head is press-fitted into the small-diameter hole, the tip of the head has the plug-side hole. It is good to be projected to. Thereby, conduction between the screw terminal for cord connection and the plug connector side can be further ensured.
[0013]
According to a sixth aspect of the present invention, there is provided a plug-side hole to which a plug connector for connecting a terminal of an ignition plug is attached, and a cord side to which a cord-connecting screw terminal for connecting a female screw terminal of a plug cord by a screwing method is attached. A method for manufacturing a plug cap, comprising: a plug cap body made of a resin molded product having a hole; and the cord connection screw terminal attached to the cord side hole,
The plug cap main body is provided with a small-diameter hole having an inner diameter smaller than the inner diameter of a portion near the opening end at a depth from the opening end of the cord-side hole so as to communicate with the plug-side hole. On the other hand,
The cord connection screw terminal is a screw member with a head, and the head of the screw is pressed into the small-diameter hole portion of the plug cap body before being formed and solidified with the tip of the screw being the open end side. A method of manufacturing the plug cap, wherein the tip of the head is exposed to the plug-side hole, and the head is tightened and attached by contraction of the resin of the plug cap body accompanying solidification thereafter. .
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of such a plug cap will be described in detail with reference to FIGS. In the figure, reference numeral 1 denotes a plug cap main body (hereinafter, also referred to as a cap main body or simply a main body) made of a thermosetting resin (for example, a phenol resin) constituting the plug cap 101. The main body 1 includes a plug-side hole forming cylinder portion 5 having a plug-side hole 3 to which a plug connector for terminal connection of an ignition plug (not shown) is attached, and a cord connection screw terminal 21 for plug cord connection. Is mainly composed of a cord-side hole forming tubular portion 15 having a cord-side hole 13 to which the hole is attached.
[0015]
Of these, the plug-side hole forming cylinder portion 5 is connected to a large-diameter straight pipe portion 6 having a circular cross section and a large outer diameter with respect to the center axis Gl via a tapered portion 7 and has a reduced diameter. The diameter straight pipe part 8 is provided. The plug-side hole 3 is formed concentrically with the axis Gl inside the plug-side hole forming cylindrical portion 5 and has a circular cross section. However, the plug-side hole 3 is formed from a large-diameter hole 3a near the opening end (lower end) of the plug-side hole forming cylindrical portion 5 via a screw (female screw) portion 4 having a slightly smaller diameter than the hole 3a. Are smaller diameter holes 3b.
[0016]
On the other hand, in the present embodiment, the cord-side hole forming tubular portion 15 has a circular cross section and the same outer diameter, and is formed obliquely projecting from a portion near the upper end of the plug-side hole forming tubular portion 5. However, the central axis G2 of the cord-side hole-forming cylinder 15 and the center axis Gl of the plug-side hole-forming cylinder 5 are formed such that the intersection angle θ thereof is, for example, 120 degrees when viewed from the front. . The cord-side hole 13 has a hole 13 a having a circular cross section concentric with the axis G <b> 2 inside the cord-side hole forming cylindrical portion 15. Is provided with a small-diameter hole portion 16 having a circular cross section, which is smaller in diameter than the portion near the opening end 14 (see FIG. 2). The small-diameter hole 16 includes a portion corresponding to the cylindrical wall 8 a of the plug-side hole forming cylindrical portion 5 that forms the plug-side hole 3, and communicates with the back of the plug-side hole 3. I have. Thus, in the present embodiment, both the cord-side holes 13 and the plug-side holes 3 communicate with each other in a bent shape at 120 degrees. A circular flange 6a is formed on the outer peripheral surface of the lower end portion of the plug-side hole forming cylindrical portion 5 so as to protrude in the radial direction of the plug cap 101, and the upper end portion has a shaft having a diameter-enlarged boss at the end. A gripping portion 9 is formed to protrude in the axial direction.
[0017]
On the other hand, in the cord-side hole 13, a cord connection screw terminal 21 made of a screw member with a head 22 is attached so that the screw 23 at the tip thereof is arranged in the hole 13 a. In this embodiment, the head 22 of the screw terminal 21 for cord connection extends along the axis G3 of the screw 23 in the form of a shaft having a circular cross section, as shown in FIG. However, the portion of the head 22 closer to the tip is a concentric and narrower circular shaft portion 25, and the portion closer to the screw 23 (the portion closer to the tip) 26 is relatively thicker as a whole, and has a small-diameter hole. 16 to be located. The plug cap 101 with the screw terminal 21 for cord connection is formed immediately after the plug cap body 1 is removed from the mold by injection molding and before the resin is solidified (in a soft state having shape retention). The screw terminal 21 is manufactured by pressing the screw terminal 21 from the opening end 14 side into the small-diameter hole portion 16 from the head 22 side and press-fitting (hot press-fitting) (see FIG. 2). The press-fitting is preferably performed within 60 seconds after demolding in the case of the phenolic resin of the present embodiment, and after that, natural cooling may be performed. However, in the present embodiment, after the press-fitting, the circular shaft portion 25 forming the tip of the head 22 projects into the plug-side hole 3, and as will be described later, the plug-side hole 3 The spring inserted therein is configured to be pressed.
[0018]
In the present embodiment, such a cord connection screw terminal 21 is made of, for example, brass, and is located outside a portion 26 (hereinafter also referred to as a press-fit portion) of the head portion 22 which is to be press-fitted into the small-diameter hole portion 16. The diameter is set substantially larger than the inner diameter of the small-diameter hole portion 16 before press-fitting. The press-fit portion 26 has a relatively small-diameter shaft portion 27 at a portion closer to the screw 23 and a relatively large-diameter shaft portion closer to the tip of the head 22 (the tip of the circular shaft portion 25). The part 28 is provided. However, a circular flange 29 projecting around the axis G3 is formed at the end of the small-diameter shaft portion 27 near the screw 23, and this serves as a stopper at the time of press-fitting. A large number of shafts 28 extending along the direction of the axis G3 are provided on the large-diameter shaft portion 28 of the press-fit portion 26 to be located in the small-diameter hole portion 16 of the head 22, that is, on the outer peripheral surface of the tip portion of the press-fit portion 26. Streaked irregularities (in this example, streaks formed by knurling) are formed. The outer diameter of the small-diameter shaft portion 27 of the head 22 is the same as the diameter of the valley bottom (concave groove bottom) of the stripe-shaped uneven portion. The outer diameter of the circular shaft portion 25 at the tip of the head 22 is set smaller than the inner diameter of the small-diameter hole portion 16 before press-fitting.
[0019]
As described above, in the plug cap 101 in which the screw terminals 21 are mounted by hot press-fitting before the main body 1 is solidified, in the process of solidifying the resin after press-fitting, the resin that forms the inner peripheral surface of the small-diameter hole portion 16 has the same diameter. It contracts in the radial direction and is tightly attached to the outer peripheral surface of the press-fit portion 26 of the head 22 (see FIGS. 3 and 4). That is, the resin enters the valleys (recesses) between the concave and convex portions on the outer peripheral surface of the large-diameter shaft portion 28 and adheres to the outer peripheral surface of the small-diameter shaft portion 27 of the head 22. In this embodiment, the flange 29 provided on the head 22 of the screw terminal 21 serves as a stopper at the time of press-fitting, so that the positioning accuracy in press-fitting can be improved.
[0020]
Then, as shown in FIG. 5, such a plug cap 101 inserts the coil spring 41 and the resistor 42 sequentially into the plug-side hole 3 from the opening at the lower end thereof, and A bottomed cylindrical plug connector 45 having a screw 44 formed on the outer peripheral surface is screwed into the screw portion 4 on the surface. By doing so, the coil spring 41 is compressed, and its upper end is pressed against the circular shaft portion 25 of the cord connection screw terminal 21 protruding into the depth of the plug-side hole 3 to maintain conduction.
[0021]
Next, the effect of such a plug cap 101 of the present embodiment will be described. This plug cap does not insert-mount an assembly using a relay lead wire to attach the screw terminal 21 for cord connection, so that the plug cap body 1 can be easily manufactured by a horizontal injection molding machine. For this reason, the number of molded plug cap bodies 1 can be increased even on the same mold surface. The screw terminal 21 for cord connection can be easily attached because it is hot-pressed immediately before the resin is solidified immediately after the molding of the main body 1 as described above. Therefore, the cost of the plug cap with the screw terminal 21 for cord connection can be reduced.
[0022]
In the plug cap 101 of the present embodiment, the resin is inserted into the valleys (recesses) between the streaky irregularities on the outer peripheral surface of the large-diameter shaft portion 28 of the head 22 of the attached screw terminal 21 ( 3 and 4). Therefore, when a female screw terminal of a plug cord is screwed into the cord connection screw terminal 21 and connected, for example, a large rotational force (torsion torque) T acts, it enters the concave portion on the outer peripheral surface of the large diameter shaft portion 28. Since the resin acts to prevent rotation, the screw terminals 21 are effectively prevented from loosening or coming off. Then, since such a stripe-shaped uneven portion has a shape in which the inner peripheral surface of the small-diameter hole portion 16 is cut at the time of press-fitting, smooth press-fitting can also be obtained. The inner diameter of the small-diameter hole portion 16 before press-fitting (before solidification) is substantially the same as the diameter of the concave portion (valley bottom) of the concave-convex portion of the large-diameter shaft portion 28 forming the head portion 22 so as to provide an appropriate press-fit allowance. It is good to set.
[0023]
In the present embodiment, even when a large tensile force P acts on the open end side (outward) along the axis G3 of the screw terminal 21, the resin surrounding the head 26 has a small diameter shaft close to the screw 23 at the tip. Since it is in contact with the surface of the portion 27, it acts as a stopper. As described above, in the present embodiment, exceptionally high reliability can be obtained in the mounting strength of the screw terminal 21 for cord connection. The outer diameter of the small-diameter shaft portion 27 in the head 22 may be set to be substantially the same as or slightly larger than the inner diameter of the small-diameter hole portion 16.
[0024]
The plug cap of the present embodiment also has the following effects. That is, by press-fitting the head 22 into the small-diameter hole 16, the small-diameter hole 16 receives an external force radially outward. For this reason, the small-diameter hole portion protrudes from the outer surface of the cylindrical wall 8a of the plug-side hole forming cylindrical portion 5 forming the plug-side hole 3, as shown by a two-dot chain line portion 116 in FIG. When the portion is located in the cord-side hole-forming cylinder portion 15, the cylindrical wall of the cord-side hole-forming cylinder portion 15 is deformed into a shape bulging in the radial direction due to the press-fitting of the head portion 22 and the contraction of the resin. . For this reason, depending on the press-fitting allowance, there is a possibility that problems such as cracks and cracks in the press-fitted portion may occur. However, in the present embodiment, the inner peripheral surface of the small-diameter hole portion 16 into which the head portion 22 is press-fitted exists over a portion corresponding to the cylindrical wall 8a of the plug-side hole forming cylindrical portion 5 that forms the plug-side hole 3. Therefore, the occurrence of such a problem can be effectively prevented. In particular, in the present embodiment, almost the entire large-diameter shaft portion 28 of the head portion 22 is located in the small-diameter hole portion 16 corresponding to the cylindrical wall 8a of the plug-side hole-forming cylindrical portion 5, so that Great effect.
[0025]
In the present embodiment, since the circular shaft portion 25 protruding from the tip of the head portion 22 of the cord connection screw terminal 21 protrudes into the plug side hole 3, the coil spring 41 set in the step after press-fitting. Is compressed and pressed straight, and does not impair the reliability of conduction. As shown by a two-dot chain line in FIG. 3, the circular shaft portion 25 may be formed in a tapered shape at a position near the front end.
[0026]
Incidentally, in the injection molding of the main body 1 forming the plug cap 101 of the present embodiment, since there is no insert, molding can be performed by horizontal injection molding (machine). In this case, however, the split surface (P) shown in FIG. L) (left and right forming dies (fixed plate 91, movable plate 92)). In this case, a core 95 corresponding to the inside of the plug-side hole forming cylindrical portion 5 (a core corresponding to a hole including a screw portion forming a screw portion of a plug connector) 95 is required. . For this reason, since the threaded core 95 is fitted in the cap body 1 taken out of the mold, when the cord connection screw terminal 21 is press-fitted, it is screwed down immediately after molding, and A space is provided in the back of the plug-side hole 3 so that the head end of the screw terminal can enter.
[0027]
The plug cap of the present invention is not limited to the above-described embodiment, and can be embodied by appropriately changing the design without departing from the gist thereof. For example, the screw terminal for cord connection may be changed to a shape as shown in FIGS. However, the cord connection screw terminal 51 of the present embodiment is different from the above-described embodiment only in the shape of the portion to be located in the small-diameter hole portion 16 of the head portion 22. Therefore, only the differences will be described and the same. Or, the corresponding parts are given the same reference numerals.
[0028]
That is, in the cord connection screw terminal 51 of the present embodiment, the portion 26 of the head 22 that should be located in the small-diameter hole is a cylindrical shaft portion 57 having a diameter larger than the circular shaft portion 25 at the tip of the head. In the cylindrical shaft portion 57, a concave portion (double chamfering) is provided at a portion near the screw 23 by two flat surfaces 55 parallel to each other across the axis G3. In the screw terminal 21 for cord connection in the above-described embodiment, the flange 29 is provided at the end of the head portion 22 near the screw 23. However, such a flange is not provided in the present embodiment. Thus, the head 22 is not provided with streaky irregularities, but the portion of the flat surface 55 forming the two chamfered portions of the head 22 forms a recess. Therefore, when the screw terminal 51 for cord connection is positioned by press-fitting the cylindrical shaft portion 57 of the head portion 22 into the small-diameter hole portion 16 before the resin is solidified, the flat surface forming the two-chamfered portion is formed. The resin forming the inner peripheral surface of the small-diameter hole portion 16 of the main body 1 is brought into close contact with 55 due to shrinkage accompanying the solidification thereof. Thus, the rotation of the screw terminal 51 for cord connection and the removal thereof are prevented.
[0029]
As can be understood from the above-described cord connection screw terminal 51, as a means for preventing rotation and detachment, as in the case of the screw terminal 51 of the above-described embodiment, providing a streaky uneven portion on the head 22 as in the above-described screw terminal 51. It is not limited. The cross section (cross section perpendicular to the axis) of the head of the cord connection screw terminal may be a polygon such as a quadrangle. In addition, mesh-like irregularities may be provided instead of the stripe-like irregularities.
[0030]
FIG. 9 shows another embodiment of the screw terminal 61 for cord connection. In this case, the head 62 has a circular shaft shape having substantially the same diameter, and the tip is tapered and formed. A part of the head 62 other than the tapered shape is a large-diameter shaft part 68 having a predetermined width and a diameter slightly larger than other parts, and the other part is a small-diameter shaft part 67. On the outer peripheral surface of the large-diameter shaft portion 68, a number of stripe-shaped uneven portions extending along the axial direction are formed. As shown in FIG. 9, such a cord connection screw terminal is such that a portion of the head 62 near the screw 23 including the intermediate large-diameter shaft portion 68 is press-fitted into the small-diameter hole portion 16 and attached. Therefore, an effect similar to that of the embodiment of FIG. 1 can be obtained.
[0031]
In each of the above-described embodiments, the head portion of the cord connection screw terminal is formed into a shape that prevents the screw from coming off and rotating by the resin surrounding the outer peripheral surface when the head portion is pressed into the small-diameter hole portion. . However, in the present invention, the screw member with the head is made of a resin that is in close contact with the outer peripheral surface of the head, so that the screw terminal can withstand outward pulling and rotational torque, and the female screw terminal of the plug cord can be screwed. What is necessary is just to be able to connect by the embedded method, and it is not necessarily required to be formed in this way. In addition, the head of the screw terminal only needs to be able to maintain conduction with the coil spring inserted into the plug-side hole, and therefore, even if the tip of the head does not protrude toward the plug-side hole, it is simply exposed. Or just
[0032]
In the above-described embodiment, the plug cap is embodied in a case where each axis of the plug-side hole and the cord-side hole intersects at 120 degrees, but it is needless to say that the angle can be arbitrarily set. Absent. Further, the material of the main body is not limited to the thermosetting resin, and the screw terminal may be formed of an appropriate metal material.
[0033]
【The invention's effect】
ADVANTAGE OF THE INVENTION In this invention, the plug cap with the screw terminal for cord connection with a high attachment strength can be efficiently manufactured, without using an insert and without requiring a relay lead wire. That is, since the screw terminal for cord connection is formed by press-fitting the head thereof, the number of parts is reduced, the structure and the process are simplified, and a significant reduction in manufacturing cost is expected.
[Brief description of the drawings]
FIG. 1 is a cutaway front view showing an embodiment of a plug cap according to the present invention.
FIG. 2 is a diagram showing a main body and a screw terminal for cord connection before press-fitting, which form the plug cap of FIG. 1;
FIG. 3 is an enlarged view for explaining a screw terminal part for cord connection in the plug cap of FIG. 1;
FIG. 4 is an enlarged sectional view taken along line AA of FIG. 3;
FIG. 5 is a cutaway front view in which a resistor and the like are incorporated in the plug cap of FIG. 1;
FIG. 6 is an explanatory sectional view of a molding die for molding the plug cap body of FIG. 1;
FIG. 7 is a view for explaining another embodiment of the cord connection screw terminal.
FIG. 8 is a sectional view taken along line BB in FIG. 8;
FIG. 9 is a view for explaining another embodiment of the cord connection screw terminal.
FIG. 10 is a front sectional view of a conventional plug cap.
[Explanation of symbols]
1 Plug cap main body 2, 62 Head of screw terminal for code connection 3 Plug side hole 13 Code side hole 14 Open end 16 of code side hole Small diameter hole 21, 51, 61 Screw terminal for screw connection (screw Element)
23 Screw tip 45 Plug connector 101 Plug cap

Claims

A resin molded product having a plug-side hole in which a plug connector for connecting a terminal of an ignition plug is attached, and a cord-side hole in which a screw terminal for cord connection for connecting a female screw terminal of a plug cord by a screwing method is attached. A plug cap comprising: a plug cap body consisting of: and the cord connection screw terminal attached to the cord side hole,
The plug cap body is provided with a small-diameter hole portion having an inner diameter smaller than the inner diameter of a portion near the opening end, communicating with the plug-side hole, at a depth viewed from the opening end of the cord-side hole. Yes,
The cord connection screw terminal is formed of a screw member with a head, and the head of the screw is pressed into the small-diameter hole portion of the plug cap body before being formed and solidified with the tip of the screw being the open end side. And a plug cap having a tip end of the head exposed in the plug-side hole.

In a state where the outer peripheral surface of a portion of the head that should be located in the small-diameter hole portion is mounted with the head pressed into the small-diameter hole portion, the cord connection screw terminal is positioned on the opening end side. When pulled and when twisted around the axis of the screw terminal for cord connection, the head is formed in a shape that prevents the head from slipping out and rotation by the resin surrounding the outer peripheral surface of the head. The plug cap according to claim 1, wherein

The outer diameter of a portion of the head that should be located in the small-diameter hole portion has a small diameter near the tip of the screw, a large diameter near the tip of the head, and a large diameter of the head. 2. The plug cap according to claim 1, wherein a large number of stripe-shaped uneven portions extending along the axial direction are formed on the outer peripheral surface of the portion near the front end. 3.

In the plug cap in which the axis of the plug-side hole and the axis of the screw terminal for cord connection intersect, the inner peripheral surface of the small-diameter hole into which the head is press-fitted forms the plug-side hole. The plug cap according to any one of claims 1 to 3, wherein the plug cap is present in a portion of the plug-side hole-forming cylinder portion that forms a cylinder wall.

The plug cap according to any one of claims 1 to 4, wherein, when the head is press-fitted into the small-diameter hole, a tip of the head projects into the plug-side hole.

A resin molded product having a plug-side hole in which a plug connector for connecting a terminal of an ignition plug is attached, and a cord-side hole in which a screw terminal for cord connection for connecting a female screw terminal of a plug cord by a screwing method is attached. A plug cap manufacturing method, comprising: a plug cap body comprising: and the cord connection screw terminal attached to the cord side hole,
The plug cap main body is provided with a small-diameter hole having an inner diameter smaller than the inner diameter of a portion near the opening end at a depth from the opening end of the cord-side hole so as to communicate with the plug-side hole. On the other hand,
The cord connection screw terminal is a screw member with a head, and the head of the screw is pressed into the small-diameter hole portion of the plug cap body before being formed and solidified with the tip of the screw being the open end side. A method for manufacturing a plug cap, comprising exposing a tip of the head to the plug-side hole, and tightening and attaching the head by shrinkage of a resin of the plug cap body accompanying solidification thereafter.