JP4355417B2 - Spark plug center electrode manufacturing apparatus and spark plug center electrode manufacturing method - Google Patents

Spark plug center electrode manufacturing apparatus and spark plug center electrode manufacturing method Download PDF

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JP4355417B2
JP4355417B2 JP37394699A JP37394699A JP4355417B2 JP 4355417 B2 JP4355417 B2 JP 4355417B2 JP 37394699 A JP37394699 A JP 37394699A JP 37394699 A JP37394699 A JP 37394699A JP 4355417 B2 JP4355417 B2 JP 4355417B2
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center electrode
workpiece
slide
hole
spark plug
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JP2001185325A (en
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昌秀 住
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NGK Spark Plug Co Ltd
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Description

【0001】
【発明の属する技術分野】
この発明は、スパークプラグ用中心電極の製造装置及びスパークプラグ用中心電極の製造方法に関する。
【0002】
【従来の技術】
スパークプラグの中心電極に対して旋削加工を施すための従来の製造装置の一例を図11に模式的に示す。スピンドル(回転把持部)1の中心部を貫通するセンター孔14に対して、全長lの中心電極Wを刃物台10側から、その軸心方向に挿入寸法(押込寸法)Lだけ挿入すると、センター孔14内部において、中心電極の挿入方向前端面がセンサピン13bの挿入方向後端面に接する。センサピン13bは挿入方向に押されて移動し、センター孔14から突出する挿入方向前端部がセンサ部3に到達する。センサ部3は、取付台(図示せず)に固定され、中心電極の挿入方向(以下、単に挿入方向とも言う)と略直交する光軸を有し、発光器32aと受光器32bを備えた透過形光電センサ32で構成されている。この透過形光電センサ32がセンサピン13bの挿入方向前端を感知すると、中心電極の挿入完了信号を発して、スピンドル1のチャック機構12が中心電極を回転可能に把持する。その後、チャック機構12よりも挿入方向の後方側に突出する中心電極の部位に対して旋削加工を施す(図11(a)参照)。なお、中心電極Wにおける挿入方向前端面からチャック機構12の把持位置中心までの寸法を把持寸法x、その規定寸法を規定把持寸法xとして表す。
【0003】
スパークプラグの中心電極には、耐火花消耗性向上のために、その先端部において電極母材に貴金属チップを積層状に重ね合わせ、電極母材と貴金属チップとを抵抗溶接等によって溶接接合して貴金属発火部を形成するタイプのものがある。上記旋削加工は、例えばこのような溶接接合の際に形成される溶接ビードのバリ取り等を目的として行われる。
【0004】
【発明が解決しようとする課題】
ここで、中心電極Wの挿入寸法(押込寸法)L及び全長lは、生産能率を向上させるため、型番毎に予め一定量に定められている。例えばセンター孔14内部での中心電極の引掛かり等によって中心電極の挿入寸法が不足(L’<L)した場合、透過形光電センサ32はセンサピン13bの挿入方向前端を感知せず、中心電極の挿入完了信号の代わりに、中心電極の挿入エラー信号が報知される(図11(b)参照)。一方、押込力が大きすぎたときなど、中心電極の挿入寸法が過大(L”>L)となった場合は、透過形光電センサ32はセンサピン13bの挿入方向前端を感知して、中心電極の挿入寸法が正常(L)のときと同様に中心電極の挿入完了信号を発する。すなわち、中心電極の挿入過大の場合には挿入正常の場合と区別できずに旋削加工が開始され、図11(c)のように刃物が中心電極に掛からなかったり、規定位置以外を旋削したりして、不良品を発生することがある。
【0005】
また、型番の異なる品種が混入して、規定よりも長い中心電極が挿入された場合にも同様の問題が発生する。中心電極の挿入寸法が正常(L)のとき、中心電極が規定長さlよりも小の場合(l’<l)は、透過形光電センサ32はセンサピン13bの挿入方向前端を感知せず、中心電極の挿入完了信号の代わりに、中心電極の挿入不足の場合と同様に中心電極の挿入エラー信号が報知される(図11(d)参照)。一方、中心電極が規定長さlよりも大の場合(l”>l)は、透過形光電センサ32はセンサピン13bの挿入方向前端を感知して、中心電極の全長が正常(l)のときと同様に中心電極の挿入完了信号を発する。すなわち、中心電極の全長過大の場合には全長正常の場合と区別できずに旋削加工が開始され、図11(e)のように刃物が規定位置以外を旋削したりして、不良品を発生することがある。
【0006】
このように、従来例においては、中心電極の挿入過大の場合であっても挿入正常と誤って判断され、また中心電極の全長過大の場合であっても全長正常と誤って判断される。そして、これら誤って正常と判断された中心電極に対しても自動旋削加工が施され、不良品の発生を招いていた。ここに、中心電極に対する自動旋削加工工程1サイクル(中心電極の挿入→把持→加工→排出)に要する時間は10秒以内(通常2〜5秒程度)であり、このタイムロスは生産性阻害要因として無視できないものである。しかも不良であることが発見されるのはその後の組立工程あるいはさらにその後の検査工程に至ったときであり、製造工程上の無駄が大きかった。
【0007】
本発明の課題は、中心電極に対して旋削加工を施す前の挿入段階で、不良品の発生を抑制し得るスパークプラグ用中心電極の製造装置及びスパークプラグ用中心電極の製造方法を提供することにある。
【0008】
【課題を解決するための手段及び作用・効果】
上記の課題を解決するために、本発明に係るスパークプラグ用中心電極の製造装置は、
中心電極に対して旋削加工を施し得る様に、軸線方向に挿入された該中心電極を把持し、かつ、該中心電極とともに回転可能な回転把持部と、
前記中心電極の挿入方向と一致するスライド方向にスライド可能なスライド部材と、
そのスライド部材における前記中心電極の挿入方向前端側に設けられ、該スライド部材を前記スライド方向とは逆方向に付勢して、前記中心電極の挿入に対する緩衝作用と挿入正常状態への復帰作用とを有する付勢手段と
前記中心電極の挿入に伴うスライド部材のスライド量の適否を、前記付勢手段が前記中心電極の挿入に対して前記緩衝作用と復帰作用とを発揮する時間の経過後に検出する位置検出手段とを備えることを特徴とする。
【0009】
また上記の課題を解決するために、本発明に係るスパークプラグ用中心電極の製造方法は、
中心電極の軸線方向への挿入に伴ってその挿入方向と一致するスライド方向にスライドするとともに、前記中心電極の挿入方向前端側に設けられて該中心電極の挿入に対する緩衝作用と挿入正常状態への復帰作用とを有する付勢手段により前記スライド方向とは逆方向に付勢されたスライド部材のスライド量の適否を、前記付勢手段が前記中心電極の挿入に対して前記緩衝作用と復帰作用とを発揮する時間の経過後に位置検出手段により検出する工程と、
前記位置検出手段によって前記スライド部材のスライド量が所定量であることが検出されたときに、回転把持部で前記中心電極を把持して回転することにより旋削加工を施す工程とを有することを特徴とする。
【0010】
上記本発明装置又は本発明方法によれば、中心電極の挿入に伴うスライド部材のスライド量の適否を位置検出手段で検出することによって、中心電極に対して旋削加工を施す前の挿入段階で、中心電極の把持位置の適否を検知できる。したがって、中心電極の挿入過小の場合及び中心電極の長さ過小の場合のみならず、中心電極の挿入過大の場合及び中心電極の長さ過大の場合にも不良品の発生を抑制し得る。
【0011】
しかも、本発明では、スライド部材における中心電極の挿入方向前端側に、スライド部材を、中心電極の挿入に伴うスライド方向とは逆方向に付勢する付勢手段を備えており、中心電極の挿入力が大きくて挿入過大の状態になった場合に、この付勢手段は、中心電極を挿入正常の状態へ戻す復帰作用を有している。したがって、スライド部材の位置検出手段が一時的に中心電極の挿入過大の状態を検出していても、付勢手段が中心電極を挿入正常の状態へ復帰させれば、スライド部材の位置検出手段が直ちに中心電極の挿入完了信号を発することが可能になる。そこで、中心電極の挿入力が大きくて一時的に挿入過大の状態になったときでも、挿入正常のときと同様に中心電極に対して旋削加工を施して、不良品を無駄に発生させずにすむ場合がある。また、この付勢手段は、中心電極の挿入に対する緩衝作用を有しており、中心電極の挿入力に大小のバラツキがあっても挿入に伴うスライド部材の揺れがこの緩衝作用によって素早く収束し、位置検出手段によるスライド部材の位置検出が、早く正確に行える。
【0012】
さらに本発明の位置検出手段は、スライド部材に対してスライド方向における相対位置を調整する調整部を有することにより、中心電極に対する自動旋削加工の開始前に中心電極の把持位置を容易かつ正確に決定できる。
【0013】
さらに本発明は、中心電極を軸線方向に押圧する押込部材を有することができ、中心電極をスムーズに挿入方向に押圧して、回転把持部を備えたスピンドル等のセンター孔内部での中心電極の引掛かり等によって中心電極の挿入寸法が不足する事態を防止することができる。
【0014】
さらに本発明の押込部材と回転把持部との間に、中心電極が押込部材により押圧されるときに、中心電極を支持する支持部を有することができ、中心電極の軸線を挿入方向と略一致させてスムーズな押込が可能となる。
【0015】
さらに本発明のスライド部材は、スライド方向と交差する方向に貫通された貫通孔を有し、位置検出手段を貫通孔を介してスライド量の適否を検出する透過形光電センサとすることで、コンパクトで安価な位置検出センサを用いて精度の高い位置決め制御が可能となる。
【0016】
さらに本発明は、スライド部材をスライド可能に収容するガイド部材が検出穴を有し、検出穴と貫通孔との少なくとも一部が重なったときに、透過形光電センサから発せられた光の通過を許容するものとすれば、外部光等の影響をほとんど受けることなく安定した位置決め制御が可能となる。
【0017】
【発明の実施の形態】
以下本発明の実施の形態を図面に示す実施例を参照して説明する。図1は本発明の一実施例を示すスパークプラグ用中心電極の製造装置の全体平面図である。この製造装置は図示しない旋盤のベッド上に、主軸台Aと往復台Bとを載置している。主軸台Aは、少なくとも次の各部を備えている。すなわち、中心電極のワークWをその軸心方向に挿入して回転可能に把持するスピンドル1(回転把持部)と、スピンドル1を回転させるための動力伝達部2と、主軸台Aに図示しないアーム等を介して取り付けられ、ワークWの挿入方向前端面に対する把持位置の適否を知るためのセンサ部3(位置検出手段)とである。
【0018】
また往復台Bは、少なくともバイト101を有する刃物台10を備えている。一方、ワークWの挿入方向(以下、単に挿入方向とも言う)の後方側にあって、ワークWの挿入方向後端面に接触し、ワークWを挿入方向に押圧する押込ピン4(押込部材)と、ワークWが押込ピン4により押圧されるときに、押込ピン4とスピンドル1との間にあって、ワークWを支持する支持部5とが、設けられている。
【0019】
図3はスピンドルの断面図である。スピンドル1(回転把持部)は、軸線方向に貫通したセンター孔14を有する略円筒状のスピンドル本体11の内部に、中心電極のワークWをその軸心方向に挿入して把持するチャック機構12と、ワークWの挿入に伴ってその挿入方向に連動して移動可能な連動機構13(連動部材)とを収容している。センター孔14の軸線方向とワークWの軸心方向すなわち挿入方向とは一致又は略一致させてある(図1参照)。スピンドル本体11は、両端部が開口し、ワークWを挿入する一端部の外径が他の部分よりもやや大径となる形態の略段付き円筒状の本体ケース11aと、本体ケース11aの他端部の開口内面との間で螺着される開口蓋11cを有する。
【0020】
本体ケース11aの大径部側の開口部には、チャック機構12が設けられる。ワークWの軸心に対して径方向に移動可能かつ径方向外側へ拡がるように付勢されたチャック爪12aが周方向に等間隔で3個設けられており、これらチャック爪12aが一斉に閉じてワークWを把持する。開閉アーム12bの一端部が、本体ケース11aに固定された本体ブロック11dに、支軸12cにより回動可能に支持されている。開閉アーム12bの長手方向中間部に設けられたアーム開閉バネ12dが、開閉アーム12bの他端部を開く方向に付勢している。スライド筒12eは本体ケース11aの大径部内壁面に沿ってワークW軸心方向にスライド可能であり、スライドアーム12eの先端開口部には、ワーク挿入方向の反対側へいくほど内径が大となる傾斜部12fが設けてある。そして、傾斜部12fは、開閉アーム12bの他端部に外側から嵌合して、開閉アーム12b及びチャック爪12aを径方向外側から中心部に向けて押圧する形態で設けられている。開閉アーム12bは、各々のチャック爪12aに対応して3個設けられる(図2(a)参照)。
【0021】
スライドアーム12eのスライド機構は次のようにして実現される。本体ケース11aの長手方向中間部周面に軸心方向に沿って開口する長孔11bを設け、一端部を中心に回動可能な揺動アーム12kの他端部が係合するアーム受け12iとスラストベアリング12jがこの長孔11bにスライド可能に嵌め込まれている。略円筒状で、内部に後述する連動機構13(連動部材)を収容するバネ受け筒12gが、本体ケース11aの小径部内壁面に沿ってワークW軸心方向にスライド可能に設けられている。アーム受け12iは、長孔11bを挟んでバネ受け筒12gの外周面に螺着されている。
【0022】
バネ受け筒12gのワーク挿入側の端部は前記したスライド筒12eと螺合され、他方の端部はその端面で、本体ケース11a小径部の内部に配置されたチャック開閉バネ12hの一端を受けている。チャック開閉バネ12hの他端は、前述の開口蓋11cの、本体ケース11aの小径部内壁面に面した端面で受けている。チャック開閉バネ12hは圧縮バネであり、常時チャック爪12aを閉じる方向、すなわちバネ受け筒12gをワークWの挿入方向とは反対方向へ付勢している。なお、揺動アーム12kの代わりにワークW軸心方向に往復動可能な往復動アームとしてもよく、その駆動手段は油圧、空気圧、電動モータ等既知のものが利用できる。
【0023】
ワークWの挿入時においては、軸心方向への挿入に伴うワークの変位をセンサ部3に伝達して、ワークの挿入方向前端面に対する把持位置の適否を知るために、一方ワークWの排出時においては、確実にかつ能率良くワークを自動的にスピンドル1の外へ放出するために、連動機構13(連動部材)が設けられている。ワークWの軸心と一致又は略一致した軸心を有する第一連動ピン13a(排出ピン)がスピンドル1のセンター孔14に設けられ、ワークの挿入方向前端面が第一連動ピン13aのワーク挿入方向後端面に接している。また、第一連動ピン13aの軸心と一致又は略一致した軸心を有する第二連動ピン13b(センサピン)が同じくセンター孔14に設けられる。第二連動ピン13bの一端部は第一連動ピン13aのワーク挿入方向前端部に対面し、その他端部は開口蓋11cに設けられた連通孔11eを経て、センサ部3に設けるスライダ31のワーク挿入方向後端面と接している。
【0024】
互いに向き合った第一及び第二連動ピン13a,13bの間に排出バネ13cを介在させ、これら両連動ピン13a,13bと排出バネ13cは、連動ピン収容筒14aの内部にワーク軸心方向にスライド可能に配置されている。連動ピン収容筒14aは、スピンドル1の略全長に匹敵する細長い円筒状であり、センター孔14の軸心と一致又は略一致した軸心を有し、そのワーク挿入側の端部は、本体ブロック11dに螺着されている。
【0025】
両連動ピン13a,13bの対向部間に設けられた排出バネ13cは圧縮バネであり、次のように作用する。ワークの挿入時には、押込ピン4(図1参照)の押込力により、ワークの移動は第一連動ピン13aに伝達され、排出バネ13cを圧縮させて第二連動ピン13bに接するに至る。この時点から両連動ピン13a,13b(及び排出バネ13c)は一体となってワーク挿入方向へ移動し、第二連動ピン13bのワーク挿入方向前端部がスライダ31のワーク挿入方向後端部を押圧する。押込ピン4の押込力が作用している間は戻しバネ31eの戻しバネ力に抗してスライダ31をワーク挿入方向にスライドさせる。センサ部3より挿入完了信号が発せられると押込ピン4の押込力が解除され、チャック爪12aが閉となりワークが把持される。
【0026】
ワークの排出時には、チャック爪12aが開となると、戻しバネ31eの戻しバネ力の作用によりスライダ31及び連動機構13がワーク挿入方向と逆方向に押し出され、さらに排出バネ13cの伸長が加わって第一連動ピン13aはワークWを勢いよく開口端から排出する。
【0027】
図1に示すように、電動モータ21の軸21aに固定されたモータプーリ21bと、本体ケース11aに螺合された主軸プーリ22との間にVベルト23を掛け回して動力伝達部2を形成する。再び図3において、スピンドル1は、軸受1aを介して主軸ケーシング1Aの内部に支持され、動力伝達部2により主軸ケーシング1Aに対して相対回転させられる。主軸ケーシング1Aの内部空間は、軸受1aに対する潤滑作用とスピンドル1の回転に伴う発生熱の放熱作用を有する潤滑油で満たされており、スピンドル1の両端部には軸受1aに隣接してオイルシール1bが設けられている。
【0028】
図4にセンサ部(位置検出手段)の詳細を示す。センサ部3は、ワークWの軸心方向であるスライド方向にスライド可能なスライダ31(スライド部材)と、スライダ31のスライド方向における位置を検出する透過形光電センサ32(位置検出手段)と、スライダ31に対して透過形光電センサ32をスライド方向に移動可能かつ任意の位置を保持可能に固定するアジャスタ33(調整部)とを含む。
【0029】
スライダ31におけるワーク挿入方向前端側には、スライダ31を挿入方向とは逆方向に付勢する戻しバネ31e(付勢手段)が設けられる。スライダ31と戻しバネ31eとは、これらの下方及び側方に位置するガイドブロック31bと、これらの上方に位置する上壁ブロック31b’とで構成されるガイド部材に収容されているので、スライダ31はこれらガイド部材に沿ってスライド可能である。ガイド部材の挿入方向前後端は、連動機構13の第二連動ピン(センサピン)13bの挿入方向前端部が挿通する入口を有する前壁ブロック31cと、戻しバネ31eの一端をその内壁面で受け止める後壁ブロック31dとで覆われる。
【0030】
スライド部材の位置検出手段としての透過形光電センサ32は、ワークの挿入方向と略直交する光軸を有する発光器32aと受光器32bとが、ガイドブロック31bの対向する側壁部に固定して設けられる。その際、スライダ31には光軸と略一致する軸線を有する貫通孔31aを設ける一方、ガイドブロック31bの対向する側壁部を貫通して貫通孔31aの軸線と略一致する軸線を有する検出穴32cを設けている。貫通孔31aと検出穴32cとが重なったときに、透過形光電センサ32の発光器32aから発せられた光は、貫通孔31aと検出穴32cとを通過して受光器32bに達する。このようにして透過形光電センサ32の受光器32bが透過光を感知すると、ワークの挿入完了信号を発して、スピンドル1のチャック機構12がワークの挿入方向後端部を回転可能に把持する。その後、スピンドル1よりも挿入方向の後方側に突出するワークの部位に対して旋削加工を施す。
【0031】
ここで、貫通孔31aの径と検出穴32cの径とは同径である必要はなく、また両者が完全に一致した状態の時のみ、又は一方が他方を完全に包含する状態の時のみに挿入完了信号を発するように設定する必要もない。すなわち、貫通孔31aと検出穴32cとの少なくとも一部が重なったときに、発光器32aから発せられた光が、及びを通過して受光器32bに到達して、受光器32bがこの透過光を感知できればよい。なお、検出穴32cはガイドブロック31bの対向する側壁部を貫通せず、発光器32a及び/又は受光器32bが、ガイドブロック31bの対向する側壁部に埋め込み式で設けられる場合もある。
【0032】
スライド部材の位置検出手段として、本実施例のように透過形光電センサとスライド部材の貫通孔を用いると、コンパクトで安価な製造装置とすることができる。なお、スライド部材の位置検出手段としては、反射形光電センサ又は超音波式センサとスライド部材表面、近接センサ又は磁気スケールとスライド部材の距離等既知の非接触型センサが広範囲に適用できる。また、付勢手段についても、戻しバネに代えてエアクッション型シリンダ等が利用できる。
【0033】
アジャスタ33(調整部)について、図4に示すように、調整軸33bとガイドブロック31bの下部とにそれぞれ調整ネジ33aが設けられ螺合されている。調整軸33bと一体に形成された調整摘み33b’を回転させると、透過形光電センサ32が固定されたガイドブロック31bは、基台33c上をスライダ31のスライド方向に移動する。33dはガイドブロック31bを基台33cに対して任意の位置で固定するための固定ボルト、33eは調整軸33bに挿通された座金である。
【0034】
このアジャスタ33は次のようなときに使用すると都合がよい。すなわち、最初のワークを加工するとき又は異なる型番のワークに切り換える(いわゆる段取り替え)とき、ワークに対する自動旋削加工の開始前に、まず所定の型番のワークに対して人為的に最適条件の下で旋削加工を施す。次に、加工したワークを把持した状態で、調整摘み33b’を回転させ、透過形光電センサ32をスライダ31のスライド方向に移動させる。そして、貫通孔31aと検出穴32cとが重なると、ワークの挿入完了信号が発せられる。この状態で固定ボルト33dを締め付ければ、所定の型番のワークに関して、軸心方向に対する最初のかつ最適の把持位置が決定されるので、以後はこの把持位置を倣い制御しつつ自動旋削加工を行えばよい。なお、ワークの挿入寸法は、装置側で自動的に測定・記憶するか又は人為的に測定・入力するかすればよい。
【0035】
図1を参照しつつ図3において、中心電極のワークWをチャック機構12へ挿入する際に補助的に使用される押込ピン4(押込部材)及び支持板5(支持部)について説明する。押込ピン4は、ワークの挿入方向の後方側に位置し、自身のワーク挿入方向前端面がワークの挿入方向後端面に接触して、ワークを挿入方向に押圧する。チャック機構によるワークの把持後は、ワークの加工・排出を阻害しない位置まで退避している。その押込力Fは、既に述べた戻しバネ31eの戻しバネ力F’や排出バネ13cの圧縮バネ力fより大である。したがって、特に押込ピン4の先端部は、径が細くかつ強度や耐久性が要求されるので、特殊鋼製・合金製等が用いられる場合がある。
【0036】
押込ピン4とスピンドル1との間に、ワークWが押込ピン4により押圧されるときに、ワークWを支持する支持板5が設けられている。支持板5は、ワーク挿入時に挿入方向が軸線方向から外れないようにワークを支える支持作用と、挿入されるワークに強い押込力Fが付加されて挿入寸法が過大になることを防ぐためワークに軽い抵抗を付与する抵抗付与作用を有し、補助チャック爪としての機能を果たしている。
【0037】
図2(a)に示す通り、この実施例では支持板5は、短冊状又は矩形状の一対の抵抗板5a,5aを有し、その長手方向の一辺を互いに接触させるとともに、その接触面はスピンドル1の径方向に沿わせて設けられている。この接触面は、スピンドル中心部寄りの第一接触面5a1と、第一接触面5a1が互いに接触する状態でスピンドル1の外径方向へ向けて隙間を生じる形態の第二接触面5a2とを有し、両接触面5a1,5a2の境界が回動支点5a3となっている。回動支点5a3よりも外径側における両抵抗板5a,5aの端部間に開閉バネ5bが掛け渡されている。開閉バネ5bは圧縮バネで両抵抗板5a,5aの中心部側端部を常時閉の方向に付勢している。スピンドル1の軸心を含むワーク挿通孔5c,5cが両抵抗板5a,5aに半割り状で設けられている。
【0038】
チャック爪12aが開の状態で、押込ピン4がワークWの挿入方向後端面に接触してワークWを押圧すると、両抵抗板5a,5aが閉じたままワークWがワーク挿通孔5c,5c間で抵抗を受けつつ支えられてチャック機構12内に挿入される(図2(a))。チャック爪12aが閉じてワークWを保持した状態で、支持板5を図2(b)の矢印方向に引き上げると、ワークWの外周面によって両抵抗板5a,5aの中心部側端部間が開閉バネ5bの締付バネ力に抗して押し開かれ、支持板5は所定位置に退避できる。なお、ワークWの外形に合わせてワーク挿通孔5c,5cの孔径を異ならせた複数の支持板5(抵抗板5a,5a)を準備しておくこともある。
【0039】
図3のスピンドルの作動状態を図5〜図7に示す。図5は中心電極の挿入状態を、図6は中心電極の把持状態を、図7は中心電極の排出状態をそれぞれ表している。
【0040】
図3の待機状態からワークWをセットするには、まず図5に示すように、チャック機構12を「開」とし、かつワークWを挿入する操作が必要である。そこで、揺動アーム12kを回動させアーム受け12iをワーク挿入方向(図5の右方向)へ移動させると、チャック開閉バネ12hの付勢力に抗してバネ受け筒12g及びスライド筒12eが一体となって右方向へスライドする。開閉アーム12bがアーム開閉バネ12dのバネ力で径方向外側へ開き、チャック爪12aも同様に径方向外側へ開く。支持板5のワーク挿通孔封着面5c,5cに保持されたワークWを押込ピン4が押圧すると、押込ピン4の押込力により、ワークの移動は第一連動ピン13aに伝達され、排出バネ13cを圧縮させて第二連動ピン13bに接するに至る。この時点から両連動ピン13a,13b(及び排出バネ13c)は一体となってワーク挿入方向へ移動し、第二連動ピン13bのワーク挿入方向前端部がスライダ31のワーク挿入方向後端部を押圧する。押込ピン4の押込力が作用している間は戻しバネ31eの戻しバネ力に抗してスライダ31をワーク挿入方向にスライドさせる。
【0041】
次に、図6に示すようにチャック機構12を「閉」として、ワークWを把持する操作に移る。そのために、スライダ31の貫通孔31aとガイドブロック31bの検出穴32cとが重なって、センサ部3より挿入完了信号が発せられたとき押込ピン4の押込力を解除する。それと同時に、揺動アーム12kを回動させアーム受け12iをワーク挿入方向と逆方向(図6の左方向)へ移動させると、チャック開閉バネ12hの付勢力によりバネ受け筒12g及びスライド筒12eが一体となって左方向へスライドする。開閉アーム12bがアーム開閉バネ12dのバネ力に抗して径方向内側へ閉じ、チャック爪12aも同様に径方向内側へ閉じてワークWが把持される。この状態で支持板5を所定位置に退避させ、バイト101による旋削加工をワークWに施す。
【0042】
旋削加工後のワークWを排出する操作を図7に示す。図5と同様に、揺動アーム12kを回動させアーム受け12iをワーク挿入方向(図7の右方向)へ移動させると、チャック爪12aが再び開となる。すると、戻しバネ31eの戻しバネ力の作用によりスライダ31及び連動機構13がワーク挿入方向と逆方向に押し出され、さらに排出バネ13cの伸長が加わって第一連動ピン13aはワークWを勢いよく開口端から排出する。
【0043】
図8に、透過形光電センサによるスライダの位置検出の状況を模式的に示す。自動旋削加工を実施するにあたり、ワークの挿入段階で、規定把持寸法xの位置で正しくワークを把持し得る状態か否か(把持位置の適否)を検出することが、本発明の目的とするところである。しかし、実際には規定把持寸法xを測定・検出する必要はない。全長lのワークを寸法L分挿入すれば、規定把持寸法xとともに、ワークの挿入方向前端面の位置、ひいてはセンサピン13bの挿入方向前端面の位置、さらにはスライダ31の貫通孔31aの位置が次々と決定される。結局のところ、透過形光電センサ32でスライダ31の貫通孔31aとガイドブロック31bの検出穴32cとの重なりを検出すればよいことになる。そして、検出対象であるワークWの把持位置の適否はスライダ31のスライド量の適否に置き換えて検出又は判定することができる。
【0044】
▲1▼ワークの挿入寸法Lが正常で、ワーク全長lも正常の場合(図8(a))
スピンドル1の中心部を貫通するセンター孔14に対して、全長lの中心電極Wを刃物台10側から押込ピン4の押込力により、その軸心方向に挿入寸法(押込寸法)Lだけ挿入すると、センター孔14内部において、ワークの移動は第一連動ピン13aに伝達され、排出バネ13cを圧縮させて第二連動ピン13bに接するに至る。この時点から両連動ピン13a,13b(及び排出バネ13c)は一体となってワーク挿入方向へ移動し、第二連動ピン13bのワーク挿入方向前端部がスライダ31のワーク挿入方向後端部を押圧する。押込ピン4の押込力が作用している間は戻しバネ31eの戻しバネ力に抗してスライダ31をワーク挿入方向にスライドさせる。ワークの挿入寸法Lが正常でワーク全長lも正常であれば、スライダ31のスライド量が規定量に達するので、発光器32aと受光器32bを備えた透過形光電センサ32がスライダ31の貫通孔31aとガイドブロック31bの検出穴32cとの重なりを検出して、挿入完了信号が発せられる。この挿入完了信号に基づきスピンドル1のチャック機構12がワークを回転可能に把持し、チャック機構12よりも挿入方向の後方側に突出するワークの部位に対して旋削加工を施す。
【0045】
▲2▼ワークの挿入寸法不足(L’<L)の場合(図8(b))
例えばセンター孔14内部でのワークの引掛かり等によってワークの挿入寸法が不足すると、スライダ31のスライド量が規定量に達しない。この場合、透過形光電センサ32はスライダ31の貫通孔31aとガイドブロック31bの検出穴32cとの重なりを検出することができず、挿入完了信号の代わりに、挿入エラー信号が発せられる。
【0046】
▲3▼一時的な挿入寸法過大(L”>L)の場合(図8(c)及び(c’))
例えば押込力Fが大きすぎたときなど、挿入寸法が一時的に過大となる場合がある。このときは、押込ピン4とワークWとの間、ワークWと第一連動ピン13aとの間及び第一連動ピン13aと第二連動ピン13bとの間にそれぞれα、β及びγの隙間を生じた状態が想定される。この状態では、スライダ31のスライド量が規定量より大きくなっているので、透過形光電センサ32はスライダ31の貫通孔31aとガイドブロック31bの検出穴32cとの重なりを検出することができず、挿入エラー信号が発せられる。しかし、押込ピン4の押込力Fが作用しなくなって、戻しバネ31eの戻しバネ力F’(排出バネ13cの圧縮バネ力よりも大)の作用で図8(a)と同様の図8(c’)の状態に復帰すれば、スライダ31のスライド量も規定量に復帰する。そこで、挿入完了信号が発せられ、ワークに対して旋削加工が施される。このように、この場合にも一時的に挿入エラー信号が発せられることになる。しかしこれは位置検出タイミングの問題であり解消可能である。すなわち、既述の通り戻しバネ31eがワークの挿入に対して緩衝作用と復帰作用を発揮する時間だけ、透過形光電センサ32によるスライダ31の位置検出を遅らせるか又は検出を継続すれば、挿入エラー信号は発せられなくなる。
【0047】
▲4▼ワーク全長が過小(l’<l)の場合(図8(d))
次に、型番の異なる品種が混入し、規定よりも短いワークが挿入された場合には、ワークの挿入寸法が正常(L)であれば、スライダ31のスライド量が規定量に達しない。この場合、透過形光電センサ32はスライダ31の貫通孔31aとガイドブロック31bの検出穴32cとの重なりを検出することができず、挿入エラー信号が発せられる。
【0048】
▲5▼ワーク全長が過大(l”>l)の場合(図8(e))
さらに、規定よりも長いワークが挿入された場合には、ワークの挿入寸法が正常(L)であれば、スライダ31のスライド量が規定量より大きくなる。この場合も、透過形光電センサ32はスライダ31の貫通孔31aとガイドブロック31bの検出穴32cとの重なりを検出することができず、やはり挿入エラー信号が発せられる。
【0049】
本発明に係るスパークプラグ用中心電極の製造方法のフローチャートを図9に示す。図9において、自動旋削工程にはいる前に把持位置決定スイッチがONか否かチェックする(S1)。作業の最初又は段取り替えの際は把持位置決定プログラムにより、ワークの把持位置を人為的に決定する(S2及び図10)。次いで、ワークの型番、ワーク全長l及び挿入寸法Lをプログラム内部で読み込むか又は人為的に入力する(S3)。続いて自動旋削加工を実行するために、開始スイッチ、停止スイッチ及びワーク供給について確認する(S4,S5,S6)。
【0050】
ここから自動旋削加工が実行される。チャック爪12aを「開」とし、押込ピン4でワークを挿入寸法Lだけ押し込む(S7,S8及び図5)。戻しバネ31eがワークの挿入に対して緩衝作用と復帰作用を発揮する時間だけ、透過形光電センサ32によるスライダ31の位置検出を遅らせるため、検出時間の経過を見たのち(S9))、透過形光電センサ32の受光器32bが透過光を受光したかをチェックする(S10)。受光器32bがOFFのままであれば、ワークの挿入寸法不足(L’<L)の場合(図8(b))、ワーク全長が過小(l’<l)の場合(図8(d))又はワーク全長が過大(l”>l)の場合(図8(e))のいずれかと判断して、挿入エラー信号が発せられる(S11)。一方、透過形光電センサ32がスライダ31の貫通孔31aとガイドブロック31bの検出穴32cとの重なりを検出して、受光器32bがONになれば、挿入完了信号を送出し(S12)、チャック爪を「閉」としてワークを把持する(S13及び図6)。スピンドルを回転させて旋削加工を行い(S14)、加工後はチャック爪を「開」としてワークを排出する(S15及び図7)。
【0051】
再び透過形光電センサ32の受光器32bが透過光を受光しなくなったか否かをチェックし(S16)、受光器32bがONのままであれば、ワークの詰まり発生と判断して挿入エラー信号が発せられる(S11)。最後に把持位置決定スイッチがONか否か再チェックし(S17)、段取り替えを行う場合は把持位置決定プログラム(S2)へ、自動旋削加工を継続する場合は準備チェック工程(S4)へ、それぞれ戻る。なお、図9のフローチャート1サイクルに要する時間は10秒以内(数秒程度)である。
【0052】
図10は、図9の一部をなす把持位置決定フローチャートを表す。最初のワークを加工するとき又は異なる型番のワークに切り換える(いわゆる段取り替え)とき、ワークに対する自動旋削加工の開始前に、把持位置決定プログラム(S2)を実行する。自動旋削加工を停止した後(S21)、所定の型番のワークをセットしてチャック爪を「閉」とし(S22)、人為的に最適条件の下で旋削加工を施す(S23)。次に、加工したワークを把持した状態で、調整摘み33b’を回し、透過形光電センサ32をスライダ31のスライド方向に移動させると、貫通孔31aと検出穴32cとが重なったときに、ワークの挿入完了信号が発せられる(S24)。この状態で固定ボルト33dを締め付ければ、所定の型番のワークに関して、軸心方向に対する最初のかつ最適の把持位置が決定される(S25)。以後はこの把持位置を倣い制御しつつ自動旋削加工を行うこととなる。なお、ワークの挿入寸法は、装置側で自動的に測定・記憶するか又は人為的に測定・入力するかすればよい。
【図面の簡単な説明】
【図1】本発明の一実施例を示すスパークプラグ用中心電極の製造装置の全体平面図。
【図2】図1のX−X矢視側面図。
【図3】スピンドルの縦断面図。
【図4】センサ部の詳細図。
【図5】中心電極の挿入状態を示す図3のスピンドルの縦断面図。
【図6】中心電極の把持状態を示す図3のスピンドルの縦断面図。
【図7】中心電極の排出状態を示す図3のスピンドルの縦断面図。
【図8】透過形光電センサによるスライダの位置検出を示す模式図。
【図9】本発明に係るスパークプラグ用中心電極の製造方法を示すフローチャート。
【図10】図9の一部をなす把持位置決定フローチャート。
【図11】従来の位置検出を示す、図8に相当する模式図。
【符号の説明】
1 スピンドル(回転把持部)
4 押込ピン(押込部材)
5 支持板(支持部)
13 連動機構(連動部材)
31 スライダ(スライド部材)
31a 貫通孔
31b ガイドブロック(ガイド部材)
31b’上壁ブロック(ガイド部材)
31e 戻しバネ(付勢手段)
32 透過形光電センサ(位置検出手段)
32c 検出穴
33 アジャスタ(調整部)
W ワーク(中心電極)
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spark plug center electrode manufacturing apparatus and a spark plug center electrode manufacturing method.
[0002]
[Prior art]
An example of a conventional manufacturing apparatus for performing a turning process on the center electrode of the spark plug is schematically shown in FIG. When a center electrode W having a total length of 1 is inserted into the center hole 14 penetrating through the center of the spindle (rotary gripping portion) 1 from the tool post 10 side in the axial direction by an insertion dimension (pushing dimension) L, Inside the hole 14, the front end surface of the center electrode in the insertion direction is in contact with the rear end surface of the sensor pin 13b in the insertion direction. The sensor pin 13 b is pushed and moved in the insertion direction, and the front end portion in the insertion direction protruding from the center hole 14 reaches the sensor unit 3. The sensor unit 3 is fixed to a mounting base (not shown), has an optical axis substantially orthogonal to the insertion direction of the center electrode (hereinafter also simply referred to as the insertion direction), and includes a light emitter 32a and a light receiver 32b. The transmissive photoelectric sensor 32 is configured. When the transmission photoelectric sensor 32 senses the front end of the sensor pin 13b in the insertion direction, a center electrode insertion completion signal is issued, and the chuck mechanism 12 of the spindle 1 grips the center electrode in a rotatable manner. Thereafter, a turning process is performed on the portion of the center electrode that protrudes rearward in the insertion direction from the chuck mechanism 12 (see FIG. 11A). Note that the dimension from the front end surface in the insertion direction of the center electrode W to the center of the gripping position of the chuck mechanism 12 is the gripping dimension x, and the specified dimension is the specified gripping dimension x.0Represent as
[0003]
In order to improve spark wear resistance, the spark plug center electrode has a noble metal tip stacked on the electrode base material at the tip, and the electrode base material and the noble metal tip are welded together by resistance welding or the like. There is a type that forms a precious metal ignition part. The turning process is performed for the purpose of deburring a weld bead formed at the time of such welding joining, for example.
[0004]
[Problems to be solved by the invention]
Here, the insertion dimension (pushing dimension) L and the total length l of the center electrode W are determined in advance for each model number in order to improve the production efficiency. For example, when the insertion dimension of the center electrode is insufficient (L ′ <L) due to the center electrode being caught inside the center hole 14, the transmission photoelectric sensor 32 does not detect the front end of the sensor pin 13 b in the insertion direction, and the center electrode Instead of the insertion completion signal, an insertion error signal of the center electrode is notified (see FIG. 11B). On the other hand, when the insertion dimension of the center electrode becomes excessive (L ″> L), such as when the pushing force is too large, the transmission photoelectric sensor 32 detects the front end of the sensor pin 13b in the insertion direction, and The center electrode insertion completion signal is issued in the same manner as when the insertion dimension is normal (L), that is, when the center electrode is excessively inserted, turning is started without being distinguished from the normal insertion, and FIG. As shown in c), the cutter may not be applied to the center electrode or may turn other than the specified position, resulting in a defective product.
[0005]
Similar problems also occur when different types of product types are mixed and a center electrode longer than the standard is inserted. When the insertion dimension of the center electrode is normal (L) and the center electrode is smaller than the specified length l (l ′ <l), the transmission photoelectric sensor 32 does not sense the front end of the sensor pin 13b in the insertion direction. Instead of the center electrode insertion completion signal, the center electrode insertion error signal is reported in the same manner as in the case of insufficient center electrode insertion (see FIG. 11D). On the other hand, when the center electrode is larger than the specified length l (l ″> l), the transmission photoelectric sensor 32 senses the front end of the sensor pin 13b in the insertion direction, and the total length of the center electrode is normal (l). The center electrode insertion completion signal is issued in the same manner as in Fig. 11 (i.e., if the total length of the center electrode is excessive, turning is started without distinguishing it from the case where the total length is normal) Turning other parts may cause defective products.
[0006]
Thus, in the conventional example, even if the center electrode is excessively inserted, it is erroneously determined as normal insertion, and even if the center electrode is excessively full length, it is erroneously determined as full length normal. The center electrode, which is erroneously determined to be normal, is also subjected to automatic turning, resulting in the generation of defective products. Here, the time required for one cycle of the automatic turning process for the center electrode (insertion of the center electrode → gripping → processing → discharge) is within 10 seconds (usually about 2 to 5 seconds), and this time loss is a factor that hinders productivity. It cannot be ignored. Moreover, it was discovered that it was defective when it reached the subsequent assembly process or further inspection process, and the manufacturing process was very wasteful.
[0007]
An object of the present invention is to provide a spark plug center electrode manufacturing apparatus and a spark plug center electrode manufacturing method capable of suppressing the occurrence of defective products at the insertion stage before turning the center electrode. It is in.
[0008]
[Means for solving the problems and actions / effects]
  In order to solve the above-described problem, a spark plug center electrode manufacturing apparatus according to the present invention includes:
  A rotary gripping part that grips the central electrode inserted in the axial direction and can rotate together with the central electrode so that turning can be performed on the central electrode;
  Of the central electrodeIn the sliding direction that matches the insertion directionA slidable slide member;
  Provided on the front end side in the insertion direction of the center electrode in the slide member,The slide memberThe aboveEnergized in the direction opposite to the slide directionAnd having a buffering action against the insertion of the center electrode and a returning action to the normal state of insertion.Energizing means and,
  Appropriate slide amount of the slide member with the insertion of the center electrode, After a lapse of time during which the biasing means exhibits the buffering action and the returning action with respect to the insertion of the center electrodeDetecting position detecting meansWithIt is characterized by that.
[0009]
  In order to solve the above-mentioned problem, a method for manufacturing a center electrode for a spark plug according to the present invention includes:
  With the insertion of the center electrode in the axial directionIn the slide direction that matches the insertion directionAs you slide,The biasing means provided on the front end side in the insertion direction of the center electrode has a buffering action against insertion of the center electrode and a returning action to a normal insertion state.Whether the sliding amount of the sliding member biased in the direction opposite to the sliding direction is appropriate, After a lapse of time during which the biasing means exhibits the buffering action and the returning action with respect to the insertion of the center electrodeDetecting by position detecting means;
  By the position detecting meansWhen it is detected that the slide amount of the slide member is a predetermined amount,At the rotating gripHolding the center electrodeBy rotatingAnd a step of performing a turning process.
[0010]
According to the device of the present invention or the method of the present invention, by detecting whether or not the sliding amount of the slide member accompanying the insertion of the center electrode is appropriate by the position detection means, in the insertion stage before turning the center electrode, Appropriateness of the holding position of the center electrode can be detected. Therefore, it is possible to suppress the occurrence of defective products not only when the center electrode is excessively inserted and when the center electrode is excessively short, but also when the center electrode is excessively inserted and when the center electrode is excessively long.
[0011]
Moreover, in the present invention, a biasing means for biasing the slide member in the direction opposite to the slide direction accompanying the insertion of the center electrode is provided on the front end side of the slide member in the direction of insertion of the center electrode. When the force is large and the insertion is excessive, the biasing means has a returning action to return the center electrode to the normal insertion state. Therefore, even if the position detection means of the slide member temporarily detects that the center electrode is excessively inserted, if the biasing means returns the center electrode to the normal insertion state, the position detection means of the slide member It becomes possible to immediately issue a center electrode insertion completion signal. Therefore, even when the insertion force of the center electrode is large and the insertion is temporarily excessive, the center electrode is turned as in the case of normal insertion so that defective products are not wasted. It may be necessary. Further, this biasing means has a buffering action against the insertion of the center electrode, and even if there is a large or small variation in the insertion force of the center electrode, the shaking of the slide member accompanying the insertion quickly converges by this buffering action, The position detection means can quickly and accurately detect the position of the slide member.
[0012]
Furthermore, the position detection means of the present invention has an adjustment unit that adjusts the relative position in the sliding direction with respect to the slide member, so that the gripping position of the center electrode can be easily and accurately determined before the automatic turning process for the center electrode is started. it can.
[0013]
Furthermore, the present invention can have a pressing member that presses the center electrode in the axial direction, and smoothly presses the center electrode in the insertion direction, so that the center electrode in the center hole such as a spindle provided with a rotary gripping portion can be A situation in which the insertion dimension of the center electrode is insufficient due to catching or the like can be prevented.
[0014]
Furthermore, when the center electrode is pressed by the pressing member between the pressing member of the present invention and the rotation gripping part, it can have a support part that supports the center electrode, and the axis of the center electrode substantially coincides with the insertion direction. Smooth pushing is possible.
[0015]
Furthermore, the slide member of the present invention has a through-hole penetrating in the direction intersecting the slide direction, and the position detection means is a transmission type photoelectric sensor that detects the suitability of the slide amount through the through-hole, thereby making the compact. Therefore, it is possible to perform highly accurate positioning control using an inexpensive position detection sensor.
[0016]
Further, according to the present invention, the guide member that slidably accommodates the slide member has a detection hole, and when at least a part of the detection hole and the through hole overlap, passage of light emitted from the transmission type photoelectric sensor is prevented. If it is allowed, stable positioning control can be performed with almost no influence of external light or the like.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to examples shown in the drawings. FIG. 1 is an overall plan view of a spark plug center electrode manufacturing apparatus according to an embodiment of the present invention. In this manufacturing apparatus, a headstock A and a carriage B are placed on a lathe bed (not shown). The headstock A includes at least the following parts. That is, a spindle 1 (rotary gripping part) that rotatably inserts the workpiece W of the center electrode in the axial direction thereof, a power transmission part 2 for rotating the spindle 1, and an arm (not shown) on the headstock A And a sensor unit 3 (position detecting means) for knowing the suitability of the gripping position with respect to the front end surface of the workpiece W in the insertion direction.
[0018]
The carriage B includes a tool post 10 having at least a cutting tool 101. On the other hand, a push pin 4 (pushing member) that is on the rear side in the insertion direction of the workpiece W (hereinafter also simply referred to as the insertion direction), contacts the rear end surface of the workpiece W in the insertion direction, and presses the workpiece W in the insertion direction. When the workpiece W is pressed by the pressing pin 4, a support portion 5 is provided between the pressing pin 4 and the spindle 1 to support the workpiece W.
[0019]
FIG. 3 is a sectional view of the spindle. The spindle 1 (rotary gripping portion) includes a chuck mechanism 12 that inserts and grips a workpiece W of the center electrode in the axial direction inside a substantially cylindrical spindle body 11 having a center hole 14 penetrating in the axial direction. In addition, an interlocking mechanism 13 (interlocking member) that can move in conjunction with the insertion direction of the work W is accommodated. The axial direction of the center hole 14 and the axial center direction of the workpiece W, that is, the insertion direction are matched or substantially matched (see FIG. 1). The spindle main body 11 has a substantially stepped cylindrical main body case 11a in which both end portions are open and the outer diameter of one end portion into which the workpiece W is inserted is slightly larger than other portions, and the main body case 11a. It has the opening lid | cover 11c screwed between the opening inner surfaces of an edge part.
[0020]
A chuck mechanism 12 is provided in the opening on the large diameter side of the main body case 11a. Three chuck claws 12a urged so as to be movable in the radial direction with respect to the axis of the workpiece W and spread outward in the radial direction are provided at equal intervals in the circumferential direction, and these chuck claws 12a are simultaneously closed. To grip the workpiece W. One end of the opening / closing arm 12b is rotatably supported by a main body block 11d fixed to the main body case 11a by a support shaft 12c. An arm opening / closing spring 12d provided at an intermediate portion in the longitudinal direction of the opening / closing arm 12b biases the other end of the opening / closing arm 12b to open. The slide cylinder 12e is slidable along the inner wall surface of the large-diameter portion of the main body case 11a, and the inner diameter of the tip opening of the slide arm 12e increases toward the opposite side of the workpiece insertion direction. An inclined portion 12f is provided. The inclined portion 12f is provided in such a form that it is fitted to the other end portion of the opening / closing arm 12b from the outside and presses the opening / closing arm 12b and the chuck claw 12a from the radially outer side toward the center portion. Three open / close arms 12b are provided corresponding to each chuck claw 12a (see FIG. 2A).
[0021]
The slide mechanism of the slide arm 12e is realized as follows. An arm receiver 12i that is provided with a long hole 11b that opens along the axial direction on the circumferential surface of the intermediate portion in the longitudinal direction of the main body case 11a, and that engages with the other end of the swing arm 12k that can rotate around one end. A thrust bearing 12j is slidably fitted into the long hole 11b. A spring receiving cylinder 12g, which is substantially cylindrical and accommodates an interlocking mechanism 13 (interlocking member), which will be described later, is provided so as to be slidable along the inner wall surface of the small-diameter portion of the main body case 11a. The arm receiver 12i is screwed to the outer peripheral surface of the spring receiving cylinder 12g with the elongated hole 11b interposed therebetween.
[0022]
The end of the spring receiving cylinder 12g on the workpiece insertion side is screwed with the above-described slide cylinder 12e, and the other end is an end surface thereof, and receives one end of a chuck opening / closing spring 12h arranged inside the small diameter portion of the main body case 11a. ing. The other end of the chuck opening / closing spring 12h is received by an end surface of the opening lid 11c facing the inner wall surface of the small diameter portion of the main body case 11a. The chuck opening / closing spring 12h is a compression spring, and always biases the chuck claw 12a in the closing direction, that is, the spring receiving cylinder 12g in the direction opposite to the insertion direction of the workpiece W. Instead of the swing arm 12k, a reciprocating arm that can reciprocate in the direction of the workpiece W axis may be used, and known driving means such as hydraulic, pneumatic, and electric motors can be used.
[0023]
When the workpiece W is inserted, the displacement of the workpiece accompanying the insertion in the axial direction is transmitted to the sensor unit 3 so as to know whether the gripping position is appropriate with respect to the front end surface of the workpiece in the insertion direction. , An interlocking mechanism 13 (interlocking member) is provided in order to reliably and efficiently release the workpiece out of the spindle 1 automatically. A first interlocking pin 13a (discharge pin) having an axis that coincides with or substantially coincides with the axis of the work W is provided in the center hole 14 of the spindle 1, and the work insertion direction front end surface is the first interlocking pin 13a. It is in contact with the direction rear end face. Further, a second interlocking pin 13b (sensor pin) having an axis that coincides with or substantially coincides with the axis of the first interlocking pin 13a is also provided in the center hole 14. One end of the second interlocking pin 13b faces the front end of the first interlocking pin 13a in the workpiece insertion direction, and the other end of the second interlocking pin 13b passes through the communication hole 11e provided in the opening lid 11c, and the workpiece of the slider 31 provided in the sensor unit 3 It is in contact with the rear end surface in the insertion direction.
[0024]
A discharge spring 13c is interposed between the first and second interlocking pins 13a and 13b facing each other, and both the interlocking pins 13a and 13b and the discharge spring 13c slide in the work pin center direction inside the interlocking pin housing cylinder 14a. Arranged to be possible. The interlocking pin accommodating cylinder 14a has an elongated cylindrical shape comparable to the substantially entire length of the spindle 1 and has an axis that coincides with or substantially coincides with the axis of the center hole 14, and its end on the work insertion side is a main body block. It is screwed to 11d.
[0025]
The discharge spring 13c provided between the opposing portions of the two interlocking pins 13a and 13b is a compression spring and operates as follows. When the workpiece is inserted, the movement of the workpiece is transmitted to the first interlocking pin 13a by the pressing force of the pressing pin 4 (see FIG. 1), and the discharge spring 13c is compressed to come into contact with the second interlocking pin 13b. From this point, both interlocking pins 13a and 13b (and discharge spring 13c) move together in the workpiece insertion direction, and the front end of the second interlocking pin 13b presses the rear end of the slider 31 in the workpiece insertion direction. To do. While the pressing force of the pressing pin 4 is acting, the slider 31 is slid in the workpiece insertion direction against the return spring force of the return spring 31e. When an insertion completion signal is issued from the sensor unit 3, the pushing force of the pushing pin 4 is released, the chuck claw 12a is closed, and the workpiece is gripped.
[0026]
When the chuck claw 12a is opened at the time of discharging the workpiece, the slider 31 and the interlocking mechanism 13 are pushed out in the direction opposite to the workpiece insertion direction by the action of the return spring force of the return spring 31e, and the extension of the discharge spring 13c is added. One interlocking pin 13a vigorously ejects the workpiece W from the open end.
[0027]
As shown in FIG. 1, a power transmission unit 2 is formed by winding a V-belt 23 between a motor pulley 21b fixed to a shaft 21a of an electric motor 21 and a main shaft pulley 22 screwed into a main body case 11a. . In FIG. 3 again, the spindle 1 is supported inside the spindle casing 1A via the bearing 1a, and is rotated relative to the spindle casing 1A by the power transmission unit 2. The inner space of the spindle casing 1A is filled with a lubricating oil having a lubricating action for the bearing 1a and a heat radiating action for heat generated by the rotation of the spindle 1, and oil seals are provided at both ends of the spindle 1 adjacent to the bearing 1a. 1b is provided.
[0028]
  FIG. 4 shows details of the sensor unit (position detecting means). The sensor unit 3 is in the axial direction of the workpiece WIs the slide directionA slidable slider 31 (sliding member), a transmissive photoelectric sensor 32 (position detecting means) for detecting the position of the slider 31 in the sliding direction, and the transmissive photoelectric sensor 32 can be moved in the sliding direction relative to the slider 31. And an adjuster 33 (adjustment unit) that fixes an arbitrary position so as to be held.
[0029]
On the front end side of the slider 31 in the workpiece insertion direction, a return spring 31e (biasing means) that biases the slider 31 in the direction opposite to the insertion direction is provided. Since the slider 31 and the return spring 31e are accommodated in a guide member constituted by a guide block 31b positioned below and on the side of the slider 31 and an upper wall block 31b ′ positioned above the slider 31 and the return spring 31e. Is slidable along these guide members. The front and rear ends of the guide member in the insertion direction are after the front wall block 31c having an entrance through which the front end of the second interlocking pin (sensor pin) 13b of the interlocking mechanism 13 is inserted and the one end of the return spring 31e received by the inner wall surface thereof. It is covered with a wall block 31d.
[0030]
A transmissive photoelectric sensor 32 as a slide member position detecting means is provided with a light emitter 32a and a light receiver 32b having an optical axis substantially orthogonal to the workpiece insertion direction fixed to opposite side walls of the guide block 31b. It is done. At this time, the slider 31 is provided with a through hole 31a having an axis substantially coincident with the optical axis, while passing through the opposing side wall portion of the guide block 31b and having an axis substantially coincident with the axis of the through hole 31a. Is provided. When the through hole 31a and the detection hole 32c overlap, the light emitted from the light emitter 32a of the transmission photoelectric sensor 32 passes through the through hole 31a and the detection hole 32c and reaches the light receiver 32b. When the light receiver 32b of the transmissive photoelectric sensor 32 senses the transmitted light in this way, a workpiece insertion completion signal is issued, and the chuck mechanism 12 of the spindle 1 grips the rear end portion in the workpiece insertion direction in a rotatable manner. After that, turning is performed on the part of the workpiece protruding rearward in the insertion direction from the spindle 1.
[0031]
Here, the diameter of the through hole 31a and the diameter of the detection hole 32c do not need to be the same diameter, and only when the two are completely coincident or only when one is completely including the other. There is no need to set to issue an insertion completion signal. That is, when at least a part of the through hole 31a and the detection hole 32c overlap, the light emitted from the light emitter 32a passes through and reaches the light receiver 32b, and the light receiver 32b transmits this transmitted light. It only has to be able to sense. In some cases, the detection hole 32c does not penetrate the opposing side wall portion of the guide block 31b, and the light emitter 32a and / or the light receiver 32b are embedded in the opposing side wall portion of the guide block 31b.
[0032]
If the transmission type photoelectric sensor and the through hole of the slide member are used as the position detection means of the slide member as in this embodiment, a compact and inexpensive manufacturing apparatus can be obtained. As the position detection means of the slide member, a known non-contact type sensor such as a reflective photoelectric sensor or ultrasonic sensor and the slide member surface, a proximity sensor or a distance between the magnetic scale and the slide member can be applied in a wide range. As for the biasing means, an air cushion type cylinder or the like can be used instead of the return spring.
[0033]
As shown in FIG. 4, the adjuster 33 (adjustment unit) is provided with an adjustment screw 33a and screwed onto the adjustment shaft 33b and the lower portion of the guide block 31b. When the adjustment knob 33b 'formed integrally with the adjustment shaft 33b is rotated, the guide block 31b to which the transmission photoelectric sensor 32 is fixed moves on the base 33c in the sliding direction of the slider 31. 33d is a fixing bolt for fixing the guide block 31b to the base 33c at an arbitrary position, and 33e is a washer inserted through the adjustment shaft 33b.
[0034]
This adjuster 33 is conveniently used in the following cases. That is, when machining the first workpiece or switching to a workpiece with a different model number (so-called setup change), before starting automatic turning on the workpiece, Turn. Next, in a state where the processed workpiece is gripped, the adjustment knob 33 b ′ is rotated, and the transmission photoelectric sensor 32 is moved in the sliding direction of the slider 31. When the through hole 31a and the detection hole 32c overlap, a workpiece insertion completion signal is issued. If the fixing bolt 33d is tightened in this state, the first and optimum gripping position with respect to the axial center direction is determined for a workpiece of a predetermined model number. Thereafter, automatic turning is performed while controlling the gripping position. Just do it. The workpiece insertion dimension may be automatically measured / stored on the apparatus side or artificially measured / input.
[0035]
Referring to FIG. 3, the push pin 4 (push member) and the support plate 5 (support portion) that are used supplementarily when the workpiece W of the center electrode is inserted into the chuck mechanism 12 will be described. The push pin 4 is located on the rear side in the workpiece insertion direction, and its front end surface in the workpiece insertion direction comes into contact with the rear end surface in the workpiece insertion direction to press the workpiece in the insertion direction. After gripping the workpiece by the chuck mechanism, the workpiece is retracted to a position that does not hinder workpiece processing / discharge. The pushing force F is larger than the return spring force F ′ of the return spring 31 e and the compression spring force f of the discharge spring 13 c described above. Accordingly, the tip portion of the push-in pin 4 is particularly thin and requires strength and durability, so that special steels and alloys may be used.
[0036]
A support plate 5 that supports the workpiece W when the workpiece W is pressed by the pressing pin 4 is provided between the pressing pin 4 and the spindle 1. The support plate 5 is used to support the workpiece so that the insertion direction does not deviate from the axial direction when the workpiece is inserted, and to prevent the insertion size from becoming excessive due to a strong pushing force F applied to the workpiece to be inserted. It has a resistance imparting action that imparts light resistance, and functions as an auxiliary chuck claw.
[0037]
As shown in FIG. 2 (a), in this embodiment, the support plate 5 has a pair of strip-like or rectangular resistance plates 5a, 5a, which are in contact with each other in the longitudinal direction, and the contact surface is It is provided along the radial direction of the spindle 1. This contact surface has a first contact surface 5a1 near the center of the spindle and a second contact surface 5a2 configured to create a gap in the outer diameter direction of the spindle 1 in a state where the first contact surfaces 5a1 are in contact with each other. And the boundary of both contact surface 5a1, 5a2 is the rotation fulcrum 5a3. An open / close spring 5b is stretched between the ends of the resistance plates 5a, 5a on the outer diameter side of the rotation fulcrum 5a3. The open / close spring 5b is a compression spring and urges the ends of the resistance plates 5a, 5a on the center side in the normally closed direction. Workpiece insertion holes 5c and 5c including the shaft center of the spindle 1 are provided in a half-divided shape on both resistance plates 5a and 5a.
[0038]
When the push pin 4 is in contact with the rear end surface in the insertion direction of the workpiece W and presses the workpiece W with the chuck claw 12a opened, the workpiece W is placed between the workpiece insertion holes 5c and 5c with both the resistance plates 5a and 5a closed. Then, it is supported while receiving resistance and inserted into the chuck mechanism 12 (FIG. 2A). When the support plate 5 is pulled up in the direction of the arrow in FIG. 2B with the chuck claw 12a closed and holding the workpiece W, the outer peripheral surface of the workpiece W causes a gap between the ends on the center side of both resistance plates 5a and 5a. The support plate 5 can be retracted to a predetermined position by being pushed open against the clamping spring force of the opening / closing spring 5b. Note that a plurality of support plates 5 (resistance plates 5a, 5a) in which the hole diameters of the workpiece insertion holes 5c, 5c are changed in accordance with the outer shape of the workpiece W may be prepared.
[0039]
The operating state of the spindle of FIG. 3 is shown in FIGS. 5 shows the inserted state of the center electrode, FIG. 6 shows the gripped state of the center electrode, and FIG. 7 shows the discharged state of the center electrode.
[0040]
In order to set the workpiece W from the standby state of FIG. 3, first, as shown in FIG. 5, an operation of opening the chuck mechanism 12 and inserting the workpiece W is required. Therefore, when the swing arm 12k is rotated to move the arm receiver 12i in the workpiece insertion direction (right direction in FIG. 5), the spring receiving cylinder 12g and the slide cylinder 12e are integrated against the biasing force of the chuck opening / closing spring 12h. And slide to the right. The open / close arm 12b is opened radially outward by the spring force of the arm open / close spring 12d, and the chuck pawl 12a is also opened radially outward. When the pressing pin 4 presses the workpiece W held on the workpiece insertion hole sealing surfaces 5c, 5c of the support plate 5, the movement of the workpiece is transmitted to the first interlocking pin 13a by the pressing force of the pressing pin 4, and the discharge spring 13c is compressed and comes into contact with the second interlocking pin 13b. From this point, both interlocking pins 13a and 13b (and discharge spring 13c) move together in the workpiece insertion direction, and the front end of the second interlocking pin 13b presses the rear end of the slider 31 in the workpiece insertion direction. To do. While the pressing force of the pressing pin 4 is acting, the slider 31 is slid in the workpiece insertion direction against the return spring force of the return spring 31e.
[0041]
Next, as shown in FIG. 6, the chuck mechanism 12 is set to “closed”, and the operation moves to the operation of gripping the workpiece W. Therefore, when the through hole 31a of the slider 31 overlaps with the detection hole 32c of the guide block 31b and an insertion completion signal is issued from the sensor unit 3, the pushing force of the pushing pin 4 is released. At the same time, when the swing arm 12k is rotated to move the arm receiver 12i in the direction opposite to the workpiece insertion direction (left direction in FIG. 6), the spring receiving cylinder 12g and the slide cylinder 12e are moved by the biasing force of the chuck opening / closing spring 12h. Slide to the left together. The open / close arm 12b closes radially inward against the spring force of the arm open / close spring 12d, and the chuck pawl 12a similarly closes radially inward to grip the workpiece W. In this state, the support plate 5 is retracted to a predetermined position, and the workpiece W is turned by the cutting tool 101.
[0042]
FIG. 7 shows an operation for discharging the workpiece W after turning. Similarly to FIG. 5, when the swing arm 12k is rotated and the arm receiver 12i is moved in the workpiece insertion direction (right direction in FIG. 7), the chuck pawl 12a is opened again. Then, the slider 31 and the interlocking mechanism 13 are pushed out in the direction opposite to the workpiece insertion direction by the action of the return spring force of the return spring 31e, and further, the extension of the discharge spring 13c is added, so that the first interlocking pin 13a opens the workpiece W vigorously. Drain from the edge.
[0043]
FIG. 8 schematically shows the state of slider position detection by the transmission photoelectric sensor. When carrying out automatic turning, the specified gripping dimension x at the workpiece insertion stage0It is an object of the present invention to detect whether or not the workpiece can be correctly gripped at this position (appropriate gripping position). However, in practice, the specified gripping dimension x0There is no need to measure and detect. If a workpiece with a total length of l is inserted for the dimension L, the specified gripping dimension x0At the same time, the position of the front end surface of the workpiece in the insertion direction, the position of the front end surface of the sensor pin 13b in the insertion direction, and the position of the through hole 31a of the slider 31 are determined one after another. After all, it is only necessary to detect the overlap between the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b with the transmission photoelectric sensor 32. The suitability of the gripping position of the workpiece W to be detected can be detected or determined by replacing the suitability of the slide amount of the slider 31.
[0044]
(1) When workpiece insertion dimension L is normal and workpiece total length l is normal (Fig. 8 (a))
When a center electrode W having a total length of 1 is inserted into the center hole 14 penetrating the center of the spindle 1 from the tool post 10 side by the pushing force of the pushing pin 4 by an insertion dimension (pushing dimension) L in the axial direction. In the center hole 14, the movement of the work is transmitted to the first interlocking pin 13a, and the discharge spring 13c is compressed to come into contact with the second interlocking pin 13b. From this point, both interlocking pins 13a and 13b (and discharge spring 13c) move together in the workpiece insertion direction, and the front end of the second interlocking pin 13b presses the rear end of the slider 31 in the workpiece insertion direction. To do. While the pressing force of the pressing pin 4 is acting, the slider 31 is slid in the workpiece insertion direction against the return spring force of the return spring 31e. If the workpiece insertion dimension L is normal and the workpiece total length l is also normal, the sliding amount of the slider 31 reaches a specified amount, so that the transmissive photoelectric sensor 32 having the light emitter 32a and the light receiver 32b is formed in the through hole of the slider 31. When an overlap between 31a and the detection hole 32c of the guide block 31b is detected, an insertion completion signal is issued. Based on the insertion completion signal, the chuck mechanism 12 of the spindle 1 grips the workpiece in a rotatable manner, and performs a turning process on a portion of the workpiece that protrudes rearward in the insertion direction from the chuck mechanism 12.
[0045]
(2) When the workpiece insertion dimension is insufficient (L '<L) (Fig. 8 (b))
For example, if the workpiece insertion dimension is insufficient due to the catching of the workpiece inside the center hole 14, the sliding amount of the slider 31 does not reach the specified amount. In this case, the transmissive photoelectric sensor 32 cannot detect the overlap between the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b, and an insertion error signal is generated instead of the insertion completion signal.
[0046]
(3) In the case of temporary excessive insertion dimension (L "> L) (FIGS. 8 (c) and (c '))
For example, when the pushing force F is too large, the insertion dimension may be temporarily excessive. At this time, clearances α, β, and γ are respectively provided between the push pin 4 and the work W, between the work W and the first interlocking pin 13a, and between the first interlocking pin 13a and the second interlocking pin 13b. The resulting state is assumed. In this state, since the sliding amount of the slider 31 is larger than the specified amount, the transmission photoelectric sensor 32 cannot detect the overlap between the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b. An insertion error signal is issued. However, the pushing force F of the pushing pin 4 does not act, and the action of the return spring force F ′ of the return spring 31e (larger than the compression spring force of the discharge spring 13c) acts as in FIG. When the state returns to the state c ′), the slide amount of the slider 31 also returns to the specified amount. Therefore, an insertion completion signal is issued, and the workpiece is turned. Thus, even in this case, an insertion error signal is temporarily issued. However, this is a problem of position detection timing and can be solved. In other words, as described above, if the return spring 31e exhibits a buffering action and a returning action for the insertion of the workpiece, the detection of the position of the slider 31 by the transmission photoelectric sensor 32 is delayed or the detection is continued. No signal is emitted.
[0047]
(4) When the overall length of the workpiece is too small (l '<l) (Fig. 8 (d))
Next, when different types of products are mixed and a workpiece shorter than the standard is inserted, if the workpiece insertion dimension is normal (L), the slide amount of the slider 31 does not reach the standard amount. In this case, the transmission photoelectric sensor 32 cannot detect the overlap between the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b, and an insertion error signal is generated.
[0048]
(5) When the total workpiece length is excessive (l "> l) (Fig. 8 (e))
Further, when a workpiece longer than the standard is inserted, if the workpiece insertion dimension is normal (L), the slide amount of the slider 31 becomes larger than the standard amount. Also in this case, the transmission photoelectric sensor 32 cannot detect the overlap between the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b, and an insertion error signal is also generated.
[0049]
FIG. 9 shows a flowchart of the manufacturing method of the spark plug center electrode according to the present invention. In FIG. 9, it is checked whether or not the grip position determination switch is ON before entering the automatic turning process (S1). At the beginning of the work or when the setup is changed, the gripping position of the workpiece is artificially determined by the gripping position determination program (S2 and FIG. 10). Next, the workpiece model number, the workpiece total length l and the insertion dimension L are read in the program or input artificially (S3). Subsequently, in order to execute automatic turning, the start switch, the stop switch, and the workpiece supply are confirmed (S4, S5, S6).
[0050]
From here, automatic turning is executed. The chuck claw 12a is set to “open”, and the workpiece is pushed in by the insertion pin L by the push pin 4 (S7, S8 and FIG. 5). Since the detection of the position of the slider 31 by the transmissive photoelectric sensor 32 is delayed by the time when the return spring 31e exhibits a buffering action and a returning action with respect to the insertion of the workpiece, the passage of the detection time is observed (S9)). It is checked whether the light receiver 32b of the photoelectric sensor 32 has received the transmitted light (S10). If the light receiver 32b remains OFF, the workpiece insertion dimension is insufficient (L '<L) (FIG. 8 (b)), or the workpiece total length is too small (l' <l) (FIG. 8 (d)). ) Or when the overall length of the workpiece is excessive (l ″> l) (FIG. 8E), an insertion error signal is issued (S11), while the transmission photoelectric sensor 32 penetrates the slider 31. When the overlap between the hole 31a and the detection hole 32c of the guide block 31b is detected and the light receiver 32b is turned on, an insertion completion signal is sent (S12), the chuck pawl is “closed”, and the workpiece is gripped (S13). And FIG. 6). Turning is performed by rotating the spindle (S14). After machining, the chuck pawl is opened and the workpiece is discharged (S15 and FIG. 7).
[0051]
It is checked again whether or not the light receiver 32b of the transmissive photoelectric sensor 32 stops receiving transmitted light (S16). If the light receiver 32b remains ON, it is determined that the workpiece is clogged and an insertion error signal is generated. It is emitted (S11). Finally, it is rechecked whether or not the grip position determination switch is ON (S17). When the setup change is performed, the grip position determination program (S2) is performed. When automatic turning is continued, the preparation check process (S4) is performed. Return. Note that the time required for one cycle of the flowchart of FIG. 9 is within 10 seconds (about several seconds).
[0052]
FIG. 10 shows a gripping position determination flowchart that forms part of FIG. When machining the first workpiece or switching to a workpiece of a different model number (so-called setup change), the gripping position determination program (S2) is executed before the start of automatic turning for the workpiece. After the automatic turning process is stopped (S21), a workpiece having a predetermined model number is set and the chuck pawl is closed (S22), and the turning process is artificially performed under optimum conditions (S23). Next, when the adjustment knob 33b ′ is turned in a state where the processed workpiece is gripped and the transmission photoelectric sensor 32 is moved in the sliding direction of the slider 31, the workpiece is moved when the through hole 31a and the detection hole 32c overlap. Insertion completion signal is issued (S24). If the fixing bolt 33d is tightened in this state, the first and optimum gripping position with respect to the axial direction is determined for the workpiece of a predetermined model number (S25). Thereafter, automatic turning is performed while controlling the gripping position. The workpiece insertion dimension may be automatically measured / stored on the apparatus side or artificially measured / input.
[Brief description of the drawings]
FIG. 1 is an overall plan view of a spark plug center electrode manufacturing apparatus according to an embodiment of the present invention.
2 is a side view taken along the line XX of FIG.
FIG. 3 is a longitudinal sectional view of a spindle.
FIG. 4 is a detailed view of a sensor unit.
5 is a longitudinal sectional view of the spindle of FIG. 3 showing a state in which the center electrode is inserted.
6 is a longitudinal sectional view of the spindle of FIG. 3 showing a gripping state of the center electrode.
7 is a longitudinal sectional view of the spindle of FIG. 3 showing a discharge state of the center electrode.
FIG. 8 is a schematic diagram showing slider position detection by a transmission photoelectric sensor.
FIG. 9 is a flowchart showing a method for manufacturing a center electrode for a spark plug according to the present invention.
FIG. 10 is a grip position determination flowchart that forms part of FIG. 9;
FIG. 11 is a schematic diagram corresponding to FIG. 8, showing conventional position detection.
[Explanation of symbols]
1 Spindle (Rotating gripper)
4 Push pin (Push member)
5 Support plate (support part)
13 Interlocking mechanism (interlocking member)
31 Slider (sliding member)
31a Through hole
31b Guide block (guide member)
31b 'upper wall block (guide member)
31e Return spring (biasing means)
32 Transmission type photoelectric sensor (position detection means)
32c detection hole
33 Adjuster (Adjustment part)
W Work (Center electrode)

Claims (7)

中心電極に対して旋削加工を施し得る様に、軸線方向に挿入された該中心電極を把持し、かつ、該中心電極とともに回転可能な回転把持部と、
前記中心電極の挿入方向と一致するスライド方向にスライド可能なスライド部材と、
そのスライド部材における前記中心電極の挿入方向前端側に設けられ、該スライド部材を前記スライド方向とは逆方向に付勢して、前記中心電極の挿入に対する緩衝作用と挿入正常状態への復帰作用とを有する付勢手段と
前記中心電極の挿入に伴うスライド部材のスライド量の適否を、前記付勢手段が前記中心電極の挿入に対して前記緩衝作用と復帰作用とを発揮する時間の経過後に検出する位置検出手段とを備えることを特徴とするスパークプラグ用中心電極の製造装置。
A rotary gripping part that grips the central electrode inserted in the axial direction and can rotate together with the central electrode so that turning can be performed on the central electrode;
A slide member slidable in a slide direction coinciding with the insertion direction of the center electrode;
The slide member is provided on the front end side of the center electrode in the insertion direction, and urges the slide member in a direction opposite to the slide direction , thereby buffering the center electrode and restoring the normal state. a biasing means having,
Position detecting means for detecting whether or not the sliding amount of the slide member accompanying the insertion of the center electrode is appropriate after a lapse of time during which the biasing means exhibits the buffering action and the returning action with respect to the insertion of the center electrode ; An apparatus for manufacturing a center electrode for a spark plug, comprising:
前記位置検出手段は、前記スライド部材に対して前記スライド方向における相対位置を調整する調整部を有する請求項1記載のスパークプラグ用中心電極の製造装置。2. The spark plug center electrode manufacturing apparatus according to claim 1, wherein the position detection unit includes an adjustment unit configured to adjust a relative position in the slide direction with respect to the slide member. 前記中心電極を前記軸線方向に押圧する押込部材を有する請求項1又は2記載のスパークプラグ用中心電極の製造装置。The manufacturing apparatus of the center electrode for spark plugs of Claim 1 or 2 which has a pushing member which presses the said center electrode in the said axial direction. 前記押込部材と前記回転把持部との間に、前記中心電極が前記押込部材により押圧されるときに、該中心電極を支持する支持部を有する請求項3記載のスパークプラグ用中心電極の製造装置。4. The spark plug center electrode manufacturing apparatus according to claim 3, further comprising: a support portion that supports the center electrode when the center electrode is pressed by the pressing member between the pressing member and the rotary grip portion. 5. . 前記スライド部材は、前記スライド方向と交差する方向に貫通された貫通孔を有する一方、
前記位置検出手段が、該貫通孔を介して前記スライド量の適否を検出する透過形光電センサである請求項1ないし4のいずれかに記載のスパークプラグ用中心電極の製造装置。
While the slide member has a through hole penetrated in a direction intersecting the slide direction,
The spark plug center electrode manufacturing apparatus according to any one of claims 1 to 4, wherein the position detection means is a transmission type photoelectric sensor that detects the suitability of the slide amount through the through hole.
前記スライド部材をスライド可能に収容するガイド部材が検出穴を有し、
該検出穴と前記貫通孔との少なくとも一部が重なったときに、前記透過形光電センサから発せられた光の通過を許容する請求項5記載のスパークプラグ用中心電極の製造装置。
A guide member that slidably accommodates the slide member has a detection hole,
6. The spark plug center electrode manufacturing apparatus according to claim 5, wherein the light emitted from the transmission photoelectric sensor is allowed to pass when at least a part of the detection hole and the through hole overlap.
中心電極の軸線方向への挿入に伴ってその挿入方向と一致するスライド方向にスライドするとともに、前記中心電極の挿入方向前端側に設けられて該中心電極の挿入に対する緩衝作用と挿入正常状態への復帰作用とを有する付勢手段により前記スライド方向とは逆方向に付勢されたスライド部材のスライド量の適否を、前記付勢手段が前記中心電極の挿入に対して前記緩衝作用と復帰作用とを発揮する時間の経過後に位置検出手段により検出する工程と、
前記位置検出手段によって前記スライド部材のスライド量が所定量であることが検出されたときに、回転把持部で前記中心電極を把持して回転することにより旋削加工を施す工程とを有することを特徴とするスパークプラグ用中心電極の製造方法。
Along with the insertion of the center electrode in the axial direction, it slides in a sliding direction that coincides with the insertion direction, and is provided on the front end side in the insertion direction of the center electrode to provide a buffering action against the insertion of the center electrode and a normal state Whether or not the sliding amount of the slide member urged in the direction opposite to the slide direction by the urging means having a return action is determined by the buffer action and the return action with respect to the insertion of the center electrode. A step of detecting by the position detecting means after the elapse of time
And a step of turning by gripping and rotating the center electrode by a rotary gripping portion when the position detecting means detects that the slide amount of the slide member is a predetermined amount. The manufacturing method of the center electrode for spark plugs.
JP37394699A 1999-12-28 1999-12-28 Spark plug center electrode manufacturing apparatus and spark plug center electrode manufacturing method Expired - Fee Related JP4355417B2 (en)

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