JP3540153B2

JP3540153B2 - Drilling tool and drilling method

Info

Publication number: JP3540153B2
Application number: JP13720898A
Authority: JP
Inventors: 順山田; 一政三浦
Original assignee: YOSHIKAWAKOGYO CO.,LTD.; Mitsubishi Materials Corp
Current assignee: YOSHIKAWAKOGYO CO.,LTD.; Mitsubishi Materials Corp
Priority date: 1998-05-19
Filing date: 1998-05-19
Publication date: 2004-07-07
Anticipated expiration: 2018-05-19
Also published as: JPH11320229A

Description

【０００１】
【発明の属する技術分野】
本発明は、穴明け加工と同時に被削材の加工穴の開口部周縁のバリ取りや面取りを行うことが可能な穴明け工具、およびかかる穴明け工具を用いた穴明け加工方法に関するものである。
【０００２】
【従来の技術】
この種の穴明け工具としては、例えば特開平８−１５５７１６号公報に記載されたものが知られている。この公報に記載された穴明け工具は、軸線回りに回転される工具本体の先端に切刃が設けられるとともに、この工具本体の先端部外周には切刃チップが、板バネ等から成るカートリッジを介して工具外周側に付勢されることにより出没自在に取り付けられている。ここで、この切刃チップは、概略正三角形平板状をなすものであって、すくい面とされる三角形面の角部に交差する二辺にはそれぞれ開口部切削刃が形成されており、このすくい面を工具回転方向に向けるとともに一の上記角部を工具外周側に位置させ、この角部に交差する上記開口部切削刃が工具先端外周側と工具後端外周側とを向いて山型に工具本体外周に突出するように取り付けられている。
【０００３】
従って、このような穴明け工具によれば、工具本体を回転させながら前進させることにより、上記切刃によって被削材に加工穴が形成されるとともに、この加工穴の開口部周縁が、上記切刃チップの工具先端外周側を向く開口部切削刃によって切削されるので、この開口部周縁に生じたバリを削り取ったり、あるいはこの開口部周縁に面取り加工を施したりすることができる。そして、さらに工具本体を前進させると、この切刃チップは、被削材の加工穴内周に押し込まれるようにして一旦工具本体内に没入し、次いで加工穴が貫通して切刃チップが該加工穴から抜け出ると、上記カートリッジに付勢されて再び工具本体外周に突出するので、ここから工具本体を後退させることにより、工具後端外周側を向く開口部切削刃によって加工穴の貫通側の開口部周縁のバリ取りや面取り加工を行うことができる。
【０００４】
【発明が解決しようとする課題】
ところで、このような穴明け工具によって被削材に貫通する加工穴を形成する穴明け加工では、特に被削材の肉厚が小さい場合などに被削材が撓んでしまうのを防ぐため、被削材の加工穴が貫通する側（工具本体の前進方向側）にサポート材を配置して被削材を支持するようにしている。ここで、被削材の撓みを確実に防ぐためには、このサポート材は上記加工穴の位置に配置されるのが望ましいのであるが、このようにサポート材を配置した場合には、穴明け工具が被削材を貫通する際に穴明け工具の切刃によってサポート材も穴明けされてしまって、被削材からサポート材に達する加工穴が形成されてしまう。このため、かかるサポート材の材質としては、サポート材が穴明けされる際の穴明け工具の上記切刃への負担を小さくしするために被削材よりも軟質な材質が用いられ、通常は、廉価であって容易に入手でき、しかも穴明けされてしまった後の廃棄も容易であることから木材が用いられたり、また被削材が鋼材である場合にはアルミニウム等の軟質金属がサポート材として用いられたりしている。
【０００５】
ところが、このようにサポート材を被削材の加工穴の位置に配置して被削材を貫通する穴明け加工を行なう場合、上記従来の穴明け工具では、被削材に形成された加工穴から切刃チップが抜け出ても、サポート材に形成された加工穴に押し込まれて切刃チップが工具本体内に没入したままの状態となってしまうため、そのまま工具本体を後退させても被削材の加工穴の貫通側の開口部周縁を切削することができないという問題があった。特に、上記公報記載の穴明け工具では、工具外周側に突出する上記切刃チップの角部が、被削材の加工穴内周面への食い込みや傷付けを防止するために工具回転方向側の負の逃げ面と工具回転方向後方側の正の逃げ面とによって構成され、しかもこの負の逃げ面と正の逃げ面、および上記負の逃げ面とこれに連なる上記開口部切削刃のすくい面となる部分とが、それぞれ互いに凸円弧状に連続するように形成されており、従ってこの角部はサポート材の加工穴の内周に上記凸円弧状の部分が滑らかに摺接するだけとなるため、穴明け工具が被削材の加工穴から引き抜かれるまでは、切刃チップは工具外周側に突出することがなく、工具後端外周側を向く開口部切削刃によって切削を行うことは不可能となる。
【０００６】
本発明は、このような事情を鑑みてなされたもので、上述のようにサポート材を配置した場合でも、被削材の加工穴の貫通側の開口部周縁の切削を行うことが可能な穴明け工具および穴明け加工方法を提供することを目的としている。
【０００７】
【課題を解決するための手段】
上記課題を解決して、このような目的を達成するために、本発明の穴明け工具は、先端に切刃を有する工具本体と、この工具本体の先端部外周に出没自在に設けられた切刃チップとを備え、上記切刃によって被削材に明けられた加工穴の開口部の周縁を上記切刃チップに形成された開口部切削刃によって切削する穴明け工具であって、上記切刃チップには、上記開口部切削刃の工具外周側に拡径用切削刃を形成し、該切刃チップが上記被削材の加工穴内にあるときには上記拡径用切削刃が上記切刃の外径よりも工具外周側に突出することがなく、かつ該切刃チップが上記加工穴から抜け出た状態では上記拡径用切削刃が上記切刃の外径よりも工具外周側に突出して上記被削材を支持するサポート材を切削するように、上記切刃チップを工具外周側に弾性的に付勢したことを特徴とする。
【０００８】
また、本発明の穴加工方法は、このような、先端に切刃を有する工具本体と、この工具本体の先端部外周に出没自在に設けられた切刃チップとを備えた穴明け工具を用いて、上記切刃によって被削材に明けられた加工穴の開口部の周縁を、上記切刃チップに形成された開口部切削刃によって切削する穴明け加工方法であって、上記被削材をサポート材によって支持する一方、上記切刃チップには上記開口部切削刃の工具外周側に拡径用切削刃を形成し、上記工具本体を前進させて、上記切刃により上記被削材を貫通して上記サポート材に達する加工穴を形成するとともに、上記切刃チップが上記被削材の加工穴から抜け出たところで上記拡径用切削刃を上記切刃の外径よりも工具外周側に突出させて、該拡径用切削刃により上記サポート材を切削して該サポート材の加工穴を拡径せしめた後、上記工具本体を後退させて、上記開口部切削刃により上記被削材の加工穴の貫通側開口部の周縁を切削することを特徴とする。
【０００９】
従って、上記構成の穴明け工具および穴明け加工方法によれば、切刃チップに拡径用切削刃が形成されていることにより、切刃チップが被削材の加工穴から抜け出たところで、この拡径用切削刃が工具本体先端の上記切刃の外径よりも工具外周側に突出して上記被削材を支持するサポート材を切削し、該サポート材に形成される加工穴の内径を拡径するとともに、切刃チップの開口部切削刃も工具外周側に突出するので、この状態から工具本体を後退させることにより、上記開口部切削刃によって被削材の加工穴の貫通側開口部周縁を切削することが可能となる。また、その一方で、切刃チップが上記被削材の加工穴内にあるときには、上記拡径用切削刃が上記切刃の外径よりも工具外周側に突出することがなく、従って被削材の加工穴内周面に上記拡径用切削刃が食い込んだり、拡径用切削刃によってこの加工穴内周面が傷つけられたりするのを防ぐことができる。
【００１０】
ここで、例えば被削材が鋼材でサポート材が木材やアルミニウム材である場合に、上述したように切刃チップが上記被削材の加工穴内にあるときには上記拡径用切削刃が上記切刃の外径よりも工具外周側に突出することがなく、かつ該切刃チップが上記加工穴から抜け出た状態では上記拡径用切削刃が上記切刃の外径よりも工具外周側に突出してサポート材を切削するようにするには、上記切刃チップを工具外周側に弾性的に付勢する付勢圧（付勢力）を、０．５〜１０kgの範囲に設定するのが望ましい。すなわち、この付勢圧が上記範囲を上回ると、拡径用切削刃が被削材の加工穴内周面に食い込んだり、傷を付けたりするおそれがある一方、上記付勢圧が上記範囲を下回ると、拡径用切削刃によってサポート材を切削することが困難となるおそれがある。また、被削材の加工穴内周への拡径用切削刃の食い込み等をより確実に防ぐには、上記拡径用切削刃に連なる外周逃げ面を、上記切刃チップが上記被削材の加工穴内にあるときにはこの加工穴の内周に摺接し、かつ該切刃チップが上記加工穴から抜け出て工具外周側に突出した状態では上記拡径用切削刃に正の逃げ角を与えるように設定するのが望ましい。
【００１１】
一方、上記切刃チップにおいて上記拡径用切削刃と開口部切削刃とが交差する部分には、この部分をこれら拡径用切削刃と開口部切削刃とに鈍角に交差する直線状に面取りしたり、あるいは両切削刃に滑らかに連なる曲線状に面取りしたりして、面取り部を形成するようにするのが望ましく、これにより、切刃チップが被削材の加工穴に挿入される際に該切刃チップを工具本体に円滑に没入させることができるとともに、拡径用切削刃と開口部切削刃とが交差する部分における欠損等を防止することができ、またこの面取り部の長さ分だけ開口部切削刃が短くなるので、被削材の加工穴周縁に面取り加工を行う場合においてはその面取り幅を調整することができる一方、上記拡径用切削刃も短くなるので、小さな付勢圧でも確実にサポート材の加工穴を拡径させることが可能となる。さらに、このような構成を採った場合には、少なくとも上記面取り部にホーニングを施すことにより、上記拡径用切削刃と開口部切削刃とが交差する部分、すなわち上記面取り部における欠損等をより確実に防止することが可能となる。
【００１２】
【発明の実施の形態】
図１ないし図６は、本発明の穴明け工具の一実施形態を示すものである。本実施形態において工具本体１は外形略円柱状をなし、その先端部の外周には、該工具本体１の軸線Ｏ回りに工具後端側に向かうに従い工具回転方向Ｔの後方側に捩れる一対の切屑排出溝２，２が工具先端に開口して後端側に延びるように形成されており、これらの切屑排出溝２，２の工具回転方向Ｔ側を向く壁面の先端にそれぞれ形成されたチップ取付座３に、超硬合金等の硬質材料より成るチップ４がろう付けされていて、このチップ４の先端に、被削材に加工穴をあけるための切刃５が形成されている。なお、工具本体１内には工具後端側から先端側に向けて切削油剤等の供給孔６が軸線Ｏに沿って形成されており、この供給孔６は工具先端側において２つに分岐して、上記切刃５，５の工具回転方向Ｔ後方側に連なる先端逃げ面７，７にそれぞれ開口している。
【００１３】
そして、この工具本体１の先端部外周には、上記先端逃げ面７，７のうちの一つに、該先端逃げ面７に開口する上記供給孔６の一つから工具外周側に向かうように開口し、かつこの先端逃げ面７に連なる工具本体１の一のランド８に工具後端側に向けて軸線Ｏに平行に延びる凹溝９が形成されており、この凹溝９に、カートリッジ１０を介して切刃チップ１１が取り付けられている。ここで、本実施形態では上記カートリッジ１０は、図３および図４に示すように凹溝９の底部に固定されるベース１０Ａに、先端部に上記切刃チップ１１を保持して凹溝９に収容される可動アーム１０Ｂが、ピン１０Ｃを介して回動自在に取り付けられるとともに、該可動アーム１０Ｂとベース１０Ａとの間には付勢部材１０Ｄとしてバネ（コイルスプリング）が介装された構成とされており、これによって上記切刃チップ１１は、可動アーム１０Ｂごと工具外周側に向けて弾性的に付勢されて、工具本体１の外周に出没自在とされた状態とされている。そして、この付勢部材１０Ｄによる付勢圧、すなわち上記コイルスプリングのバネ圧は、本実施形態では０．５〜１０kgの範囲に設定されている。
【００１４】
また、本実施形態における上記切刃チップ１１は、やはり超硬合金等の硬質材料により形成されて図５および図６に示すように概略正三角形平板状をなし、この正三角形をなす面の一つがすくい面１１Ａとされるとともに外周面が逃げ面１１Ｂとされて、このすくい面１１Ａの中央には、当該切刃チップ１１をその厚さ方向に貫通する取付穴１１Ｃが形成されている。ここで、この切刃チップ１１の上記すくい面１１Ａとされる正三角形面は、その３つの角部が各角部に対向する辺に平行となるように切り欠かれていて、これにより該切刃チップ１１は厳密には図５に示すように偏六角形平板状をなすこととなる。そして、このすくい面１１Ａの切り欠かれた角部にはそれぞれ拡径用切削刃１２が形成されるとともに、この拡径用切削刃１２の両端に連なる上記すくい面１１Ａの辺稜部には、それぞれ開口部切削刃１３，１３が形成されている。
【００１５】
なお、上記すくい面１１Ａのうち、各角部の拡径用切削刃１２と開口部切削刃１３，１３とに囲まれる等脚台形状の部分は、図６に示すように上記拡径用切削刃１２からすくい面１１Ａ中央の上記取付穴１１Ｃ側に向かうに従い、該すくい面１１Ａとは反対側の着座面１１Ｄ側に向けて一定勾配で傾斜した後、凹円弧状に切れ上がるように形成されている。また、上記逃げ面１１Ｂのうち、上記拡径用切削刃１２に連なる部分は、当該切刃チップ１１の上記厚さ方向に平行となるように形成されて、拡径用切削刃１２の逃げ角が０°となるように設定される一方、開口部切削刃１３に連なる部分は、着座面１１Ｄ側に向かうに従い上記取付穴１１Ｃ側に向かうように傾斜して形成され、開口部切削刃１３に正の逃げ角が与えられるように設定されている。
【００１６】
他方、このような切刃チップ１１が装着される上記カートリッジ１０の可動アーム１０Ｂの先端部には、当該カートリッジ１０を工具本体１の凹溝９に取り付けた状態で工具回転方向Ｔ側を向く底面１４Ａと、この底面１４Ａの周縁から屹立して工具外周側を向く壁面１４Ｂおよび該壁面１４Ｂに略６０°に交差して工具先端内周側を向く壁面１４Ｃとから画成されるチップ取付座１４が形成されている。また、上記底面１４Ａには図示されないネジ穴が形成されている。そして、上記切刃チップ１１は、上記すくい面１１Ａを工具回転方向Ｔ側に向けるとともに着座面１１Ｄを上記底面１４Ａに密着させ、またすくい面１１Ａの一の角部の上記拡径用切削刃１２を工具外周側に突出させるとともに、この拡径用切削刃１２とは反対側のすくい面１１Ａの辺稜部に連なる逃げ面１１Ｂを上記壁面１４Ｂに当接させ、かつ、この状態で工具後端外周側を向く逃げ面１１Ｂの一部を上記壁面１４Ｃに当接させて上記チップ取付座１４に着座させられ、さらに上記取付穴１１Ｃに挿通されたクランプネジ１５を上記ネジ穴にねじ込むことによってカートリッジ１０に取り付けられている。
【００１７】
次に、このように構成された穴明け工具により、サポート材Ｓに支持された被削材Ｗに穴明け加工を行って該被削材Ｗを貫通する加工穴Ｈｗを形成する場合の、本発明の穴明け加工方法の一実施形態について、図７ないし図１２に示す概略図を用いて説明する。なお、本実施形態において被削材Ｗは鋼材であり、またサポート材Ｓとしては被削材よりも軟質な木材（りん木）が用いられている。そして、このサポート材Ｓは、被削材Ｗの裏側の上記加工穴Ｈｗが貫通する位置に配置されている。
【００１８】
まず最初に、工具本体１を軸線Ｏ回りに工具回転方向Ｔに回転させつつ被削材Ｗに向けて前進させると、工具本体１最先端の上記切刃５，５が被削材Ｗに食いつき、加工穴Ｈｗの形成が始まる。そして、上記切刃チップ１１が被削材Ｗに達すると、この加工穴Ｈｗの穴明け工具挿入側（被削材Ｗの表側。図７ないし図１１においては被削材Ｗの上側）の開口部周縁Ｅ１の切削が行われる。すなわち、上記穴明け工具の工具本体１の先端部外周に突出する切刃チップ１１においては、拡径用切削刃１２が軸線Ｏに平行に配置されて工具外周側に最も突出しているとともに、この拡径用切削刃１２の両端に連なる開口部切削刃１３，１３のうち工具先端側の開口部切削刃１３は、工具先端側に向かうに従い工具内周側に向かうように傾斜して配置されることとなり、この工具先端側の開口部切削刃１３が図７に示すように上記開口部周縁Ｅ１に食いつくことによって、この開口部周縁Ｅ１に生じたバリが削り取られたり、あるいは該開口部周縁Ｅ１がテーパ面状に面取りされたりする。
【００１９】
次いで、さらに工具本体１を前進させると、傾斜した上記開口部切削刃１３が上記開口部周縁Ｅ１に案内されるようにして切刃チップ１１がカートリッジ１０の可動アーム１０Ｂごと付勢部材１０Ｄによる付勢力に抗して工具内周側に押し込まれ、これにより図８に示すように切刃チップ１１が加工穴Ｈｗ内に挿入されて上記拡径用切削刃１２が加工穴Ｈｗの内周面に当接した状態となる。このとき、本実施形態では上記付勢部材１０Ｄによる付勢圧が０．５〜１０kgの範囲に設定されているため、この拡径用切削刃１２が加工穴Ｈｗの内周面に食い込むことはなく、拡径用切削刃１２は加工穴Ｈｗの内周面に摺接しながら軸線Ｏ回りに回転するだけとなる。
【００２０】
こうして、工具本体１の前進をさらに続けると、ついには切刃５，５が被削材Ｗの裏面に達して加工穴Ｈｗが被削材Ｗを貫通するが、その後も工具本体１は前進させられ、この加工穴Ｈｗの位置に配置されたサポート材Ｓにも切刃５，５によって被削材Ｗの加工穴Ｈｗと同径の加工穴Ｈｓが形成される。そして、上記切刃チップ１１がこの加工穴Ｈｗの貫通側（被削材Ｗの裏側。図７ないし図１１において被削材Ｗの下側）の開口部周縁Ｅ２から抜け出ると、上記付勢部材１０Ｄの付勢圧が０．５〜１０kgの範囲に設定されているため、切刃チップ１１はこの付勢力によって再び工具外周側に突出し、拡径用切削刃１２がサポート材Ｓに形成された上記加工穴Ｈｓの内周面に食いついて図９に示すようにこの加工穴Ｈｓの内径を拡径するように切削する。
【００２１】
しかるに、ここから工具本体１を後退させると、上記拡径用切削刃１２の工具後端側に連なる開口部切削刃１３により、被削材の加工穴Ｈｗの貫通側の開口部周縁Ｅ２が切削される。すなわち、この工具後端側の開口部切削刃１３は、上記工具先端側の開口部切削刃１３とは逆に工具後端側に向かうに従い工具内周側に向かうように傾斜しており、工具本体１の後退に伴ってこの工具後端側の開口部切削刃１３が図１０に示すように上記開口部周縁Ｅ２に食いつくことにより、この開口部周縁Ｅ２に生じたバリが削り取られ、あるいは該開口部周縁Ｅ２がテーパ面状に面取りされる。
【００２２】
そして、さらに工具本体１を後退させると、傾斜した工具後端側の上記開口部切削刃１３が貫通側の上記開口部周縁Ｅ２に案内されるようにして、上記と同様に切刃チップ１１が可動アーム１０Ｂごと付勢部材１０Ｄによる付勢力に抗して工具内周側に再び押し込まれ、図１１に示すように切刃チップ１１が加工穴Ｈｗ内に挿入されて上記拡径用切削刃１２が加工穴Ｈｗの内周面に当接した状態となる。なお、このときにも、拡径用切削刃１２が加工穴Ｈｗの内周面に食いつくことはない。従って、このまま工具本体１を加工穴Ｈｗから抜き出すことにより、図１２に示すように被削材Ｗに、その挿入側と貫通側との開口部周縁Ｅ１，Ｅ２が切削されてバリ取りあるいは面取りされた加工穴Ｈｗが形成される。
【００２３】
このように、上記構成の穴明け工具および該穴明け工具を用いた上記穴明け加工方法では、切刃チップ１１に拡径用切削刃１２が形成されていて、この切刃チップ１１が被削材Ｗの加工穴Ｈｗから抜け出た状態で上記拡径用切削刃１２が切刃５，５の外径よりも工具外周側に突出して被削材Ｗを支持するサポート材Ｓを切削するように、該切刃チップ１１が付勢部材１０Ｄによって工具外周側に弾性的に付勢されているので、被削材Ｗの加工穴Ｈｗを抜け出て工具外周側に突出した切刃チップ１１の拡径用切削刃１２は、サポート材Ｓに形成された加工穴Ｈｓに食いついてこれを拡径してゆく。従って、工具本体１が後退する際には、こうして拡径された加工穴Ｈｓに切刃チップ１１が突出した状態であって、この切刃チップ１１の工具後端側を向く開口部切削刃１３により被削材Ｗの加工穴Ｈｗの貫通側の開口部周縁Ｅ２の切削を行うことが可能となり、上述のように挿入側と貫通側との開口部周縁Ｅ１，Ｅ２が切削された加工穴Ｈｗを被削材Ｗに形成することができる。
【００２４】
その一方で、この切刃チップ１１は、該切刃チップ１１が被削材Ｗの加工穴Ｈｗ内に挿入されているときには、上記拡径用切削刃１２が加工穴Ｈｗの内周面に当接して工具先端の切刃５，５の外径よりも工具外周側に突出することがないように付勢されており、従ってこの切刃チップ１１の拡径用切削刃１２が被削材Ｗの加工穴Ｈｗに食い込むこともないので、この加工穴Ｈｗの内周面が拡径用切削刃１２によって切削されて必要以上に加工穴Ｈｗの内径が拡げられてしまったり、あるいは加工穴Ｈｗの内周面が傷つけられて仕上面精度が損なわれてしまったりするのを防ぐことができる。そればかりか、むしろ上記構成の穴明け工具および上記穴明け加工方法によれば、このように切刃チップ１１が被削材Ｗの加工穴Ｈｗの内周面に当接しながら軸線Ｏ回りに回転することにより、いわゆるバニシング効果が生じて加工穴Ｈｗの内周面が平滑に仕上げられるので、却って良好な仕上面精度を得ることができるという効果を奏する。
【００２５】
ここで、本実施形態の穴明け工具では、被削材Ｗが鋼材であるとともにサポート材Ｓが木材であるのに対し、上記切刃チップ１１を工具外周側に付勢する付勢部材１０Ｄによる付勢圧が０．５〜１０kgの範囲に設定されており、一層確実に切刃チップ１１を上記加工穴Ｈｗの内外で出没せしめて上述の穴明け加工方法をなすことができる。すなわち、この付勢部材１０Ｄによる付勢圧が上記範囲を上回るほど大きいと、切刃チップ１１が被削材Ｗの加工穴Ｈｗの内周面に強く押し付けられすぎてしまい、拡径用切削刃１２がこの内周面に食い込んで加工穴Ｈｗを拡径してしまったり、あるいは該内周面に傷を付けて仕上げ面粗度を劣化させたりするおそれがある。
【００２６】
一方、付勢圧が上記範囲を下回るほど小さいと、切刃チップ１１が上記加工穴Ｈｗから抜け出た際に工具外周側に十分に突出せず、拡径用切削刃１２がサポート材Ｓに切り込まれなくなって該サポート材Ｓの加工穴Ｈｓを拡径させることが困難となり、従って被削材Ｗの加工穴Ｈｗの貫通側の開口部周縁Ｅ２が切削されなくなるおそれがある。なお、本実施形態ではサポート材Ｓを木材とした場合に付勢圧を上記範囲に設定しているが、例えばアルミニウム材など被削材Ｗよりも軟質な金属材をサポート材Ｓとした場合でも、この付勢圧は概ね同様の範囲に設定しておけばよい。
【００２７】
また、本実施形態の穴明け工具においては、その切刃チップ１１が略三角形平板状をなし、そのすくい面１１Ａとされる三角形面の各角部に拡径用切削刃１２が形成されるとともに、この拡径用切削刃１２の両端に開口部切削刃１３，１３が形成されており、これら開口部切削刃１３，１３に、上記開口部周縁Ｅ１，Ｅ２のバリ取りや面取り切削に適した傾斜を与えることができ、また一つの切刃チップ１１で３回の使い回しが可能となる。さらに本実施形態の切刃チップ１１では、上記拡径用切削刃１２と開口部切削刃１３，１３とにより囲まれるすくい面１１Ａの角部部分が、該拡径用切削刃１２から離間して取付穴１１Ｃ側に向かうに従いすくい面１１Ａとは反対側の着座面１１Ｄ側に向けて一定勾配で傾斜した後、凹円弧状に切れ上がるように形成されており、これにより拡径用切削刃１２の径方向すくい角を正角側に大きく設定して鋭い切れ味を与え、サポート材Ｓの加工穴Ｈｓへの拡径用切削刃１２の食いつきや切削性の向上を図ることができるという利点が得られる。
【００２８】
なお、本実施形態では、このように切刃チップ１１の拡径用切削刃１２および開口部切削刃１３，１３に囲まれるすくい面１１Ａ部分を傾斜するように形成しているが、例えばこれを図１３および図１４に示す切刃チップ２１のように、すくい面１１Ａ自体は傾斜させることなく着座面１１Ｄに平行に形成するとともに、このすくい面１１Ａの上記拡径用切削刃１２および開口部切削刃１３，１３に囲まれた部分に、これら拡径用切削刃１２および開口部切削刃１３，１３に沿って凹溝状のチップブレーカ２２を形成するようにしてもよい。この場合には、上記チップブレーカ２２によって拡径用切削刃１２および開口部切削刃１３，１３のすくい角が実質的に正角側に大きく設定されるので、上記切刃チップ１１と同様の効果を得ることができる。ただし、この図１３および図１４を初め、以下にに示す切刃チップにおいて、図５および図６に示した切刃チップ１１と共通する部分には同一の符号を配して説明を省略する。
【００２９】
一方、これらの切刃チップ１１，２１では、上記すくい面１１Ａの周りに配される逃げ面１１Ｂのうち、上記拡径用切削刃１２に連なる部分は、この拡径用切削刃１２の逃げ角が０°となるように切刃チップ１１，２１の厚さ方向に平行に形成される一方、開口部切削刃１３に連なる部分は、この開口部切削刃１３に正の逃げ角が与えられるように、着座面１１Ｄ側に向かうに従い上記取付穴１１Ｃ側に向かうように傾斜して形成されているが、被削材Ｗの加工穴Ｈｗへの拡径用切削刃１２の食い込み等をより確実に防ぐには、図１５および図１６に示す切刃チップ３１のように、逃げ面１１Ｂのうち拡径用切削刃１２に連なる外周逃げ面３２を、上記切刃５，５により形成される被削材Ｗの加工穴Ｈｗの内半径と等しい曲率半径の凸円弧面状に形成するなどして、切刃チップ３１が被削材Ｗの加工穴Ｈｗ内にあるときにはこの加工穴Ｈｗの内周面に摺接し、かつ該切刃チップ３１が上記加工穴Ｈｗから抜け出て工具外周側に突出した状態では拡径用切削刃１２に正の逃げ角を与えるように設定するのが望ましい。
【００３０】
すなわち、かかる構成の切刃チップ３１を装着した穴明け工具によれば、図１７に示すように、切刃チップ３１が被削材の加工穴Ｈｗ内にあるときには、上記外周逃げ面３２が全面的に加工穴Ｈｗの内周面に密着して当接するため、拡径用切削刃１２が加工穴Ｈｗの内周面に食い込むのが確実に防止される。その一方で、上記構成の穴明け工具において、例えば切刃チップ３１の出没方向を、上記拡径用切削刃１２が工具本体１の軸線Ｏに対する半径方向に沿って出没するように設定するなどした場合には、切刃チップ３１が被削材Ｗの加工穴Ｈｗから抜け出て工具外周側に突出したときに、図１７に示すように上記外周逃げ面３２に正の逃げ角が与えられて、この外周逃げ面３２と拡径用切削刃１２によって拡径させられた加工穴Ｈｓの内周面との間に逃げを確保することができるので、少ない抵抗で効率的に加工穴Ｈｓを拡径させることができ、被削材Ｗの加工穴Ｈｗの貫通側の開口部周縁Ｅ２の切削を確実に行うことが可能となる。
【００３１】
さらに、図１８および図１９にその一部を示す切刃チップ４１のように、すくい面１１Ａの周囲に配置される逃げ面１１Ｂにおいて、上記拡径用切削刃１２に連なる部分と上記開口部切削刃１３，１３に連なる部分との交差稜線部に平面状の面取り面４２を形成して、上記拡径用切削刃１２と開口部切削刃１３，１３とが交差する部分に、これら拡径用切削刃１２および開口部切削刃１３，１３の双方に鈍角に交差する直線状の面取り部４３を形成したり、あるいは図２０および図２１にその一部を示す切刃チップ５１のように、上記逃げ面１１Ｂの上記交差稜線部に、すくい面１１Ａの周方向に湾曲する凸曲面状の面取り面５２を形成して、上記拡径用切削刃１２と開口部切削刃１３，１３とが交差する部分に、これら拡径用切削刃１２および開口部切削刃１３，１３の双方に滑らかに連なる円弧等の凸曲線状の面取り部５３を形成したりするのが望ましい。
【００３２】
しかるに、このような構成を採った場合には、これらの切刃チップ４１，５１の工具先端側の開口部切削刃１３によって被削材Ｗの加工穴Ｈｗの挿入側の開口部周縁Ｅ１が切削された後に、工具本体１の前進に伴って切刃チップ４１，５１が加工穴Ｈｗ内に挿入されるときや、あるいは工具後端側の開口部切削刃１３によって加工穴Ｈｗの貫通側の開口部周縁Ｅ２が切削された後に、工具本体１の後退に伴って切刃チップ４１，５１が加工穴Ｈｗ内に挿入されるときに、切刃チップ４１，５１が上記面取り部４３，５３に案内されるようにして、より円滑に工具内周側に押し込まれて工具本体１の凹溝９内に没入されることとなるので、上記拡径用切削刃１２と開口部切削刃１３，１３とが交差する部分がこれらの開口部周縁Ｅ１，Ｅ２に引っ掛かって傷を付けたり、あるいは拡径用切削刃１２や開口部切削刃１３，１３に欠損等を生じたりするような事態を防止することができる。
【００３３】
また、切刃チップ４１，５１にこのような面取り部４３，５３を形成することにより、面取り部４３，５３を設けずに拡径用切削刃１２と開口部切削刃１３，１３とを直接交差させる場合に比べ、これら拡径用切削刃１２や開口部切削刃１３，１３の切刃長を短くすることができるので、開口部切削刃１３においては被削材Ｗの加工穴Ｈｗの開口部周縁Ｅ１，Ｅ２を面取り加工する際の面取り幅を調整することができる一方、拡径用切削刃１２においては付勢部材１０Ｄによる付勢圧が小さくても、確実にサポート部材Ｓを切削してその加工穴Ｈｓを拡径せしめることが可能となるという利点も得られる。
【００３４】
さらに、このような面取り部４３、５３を形成した場合には、図２２および図２３にその一部を示す切刃チップ６１のように、上記切刃チップ４１に直線状に形成された上記面取り部４３にホーニングを施して、上記面取り面４２とすくい面１１Ａとに鈍角に交差するホーニング面６２を形成したり、あるいは図２４および図２５にその一部を示す切刃チップ７１のように、上記チップ５１に凸曲線状に形成された上記面取り部５３にホーニングを施して、上記面取り面５２とすくい面１１Ａとに鈍角に交差するホーニング面７２を形成するのが望ましく、このようにホーニングを施すことにより、上記拡径用切削刃１２と開口部切削刃１３，１３とが交差する部分、すなわち上記面取り部４３，５３の欠損等を、より確実に防止することが可能となる。なお、このようなホーニングを、面取り部４３，５３の他に上記拡径用切削刃１２や開口部切削刃１３にも施すようにすれば、これら拡径用切削刃１２や開口部切削刃１３における欠損やチッピングの防止を図ることができる。
【００３５】
【発明の効果】
以上説明したように、本発明の穴明け工具および穴明け加工方法によれば、被削材を支持するサポート材が被削材に形成される加工穴の位置にあっても、この加工穴の貫通側の開口部周縁を確実に切削してバリ取りしたり、面取りしたりすることができ、より一層効率的な穴明け加工を促すことが可能となる。
【図面の簡単な説明】
【図１】本発明の穴明け工具の一実施形態を示す工具本体１先端部の側面図である。
【図２】図１に示す実施形態を工具先端側から見た正面図である。
【図３】図１に示す実施形態の切刃チップ１１周辺を示す、図２におけるＺ方向視の一部省略した側面図である。
【図４】図１に示す実施形態のカートリッジ１０および切刃チップ１１を示す側面図である。
【図５】図１に示す実施形態の切刃チップ１１の平面図である。
【図６】図５に示す切刃チップ１１の断面図である。
【図７】図１に示す実施形態の穴明け工具を用いた本発明の穴明け加工方法の一実施形態の初めの状態を示す図である。
【図８】図７の次の状態を示す図である。
【図９】図８の次の状態を示す図である。
【図１０】図９の次の状態を示す図である。
【図１１】図１０の次の状態を示す図である。
【図１２】図１１の次の状態を示す図である。
【図１３】本発明の穴明け工具の実施形態の変形例に係わる切刃チップ２１の平面図である。
【図１４】図１３に示す切刃チップ２１の断面図である。
【図１５】本発明の穴明け工具の実施形態に係わる変形例の切刃チップ３１の平面図である。
【図１６】図１５に示す切刃チップ３１の断面図である。
【図１７】図１５に示す切刃チップ３１を装着した穴明け工具により穴明け加工を行う場合を示す軸線Ｏに直交する断面図である。
【図１８】本発明の穴明け工具の実施形態に係わる変形例の切刃チップ４１の部分平面図である。
【図１９】図１８に示す切刃チップ４１の部分側面図である。
【図２０】本発明の穴明け工具の実施形態に係わる変形例の切刃チップ５１の部分平面図である。
【図２１】図２０に示す切刃チップ５１の部分側面図である。
【図２２】本発明の穴明け工具の実施形態に係わる変形例の切刃チップ６１の部分平面図である。
【図２３】図２２に示す切刃チップ６１の部分側面図である。
【図２４】本発明の穴明け工具の実施形態に係わる変形例の切刃チップ７１の部分平面図である。
【図２５】図２４に示す切刃チップ７１の部分側面図である。
【符号の説明】
１工具本体
５切刃
１０カートリッジ
１０Ｄ付勢部材
１１，２１，３１，４１，５１，６１，７１切刃チップ
１１Ａすくい面
１１Ｂ逃げ面
１２拡径用切削刃
１３開口部切削刃
２２チップブレーカ
３２外周逃げ面
４３，５３面取り部
６２，７２ホーニング面
Ｗ被削材
Ｓサポート材
Ｈｗ被削材Ｗの加工穴
Ｈｓサポート材Ｓの加工穴
Ｅ１加工穴Ｈｗの挿入側の開口部周縁
Ｅ２加工穴Ｈｗの貫通側の開口部周縁
Ｏ工具本体１の中心軸線
Ｔ工具回転方向[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drilling tool capable of deburring and chamfering the periphery of an opening of a processing hole in a work material at the same time as drilling, and to a drilling method using such a drilling tool. .
[0002]
[Prior art]
As a drilling tool of this kind, for example, a tool described in Japanese Patent Application Laid-Open No. 8-155716 is known. In the drilling tool described in this publication, a cutting blade is provided at the tip of a tool main body that is rotated around an axis, and a cutting blade tip is provided on the outer periphery of the tip of the tool main body, and a cartridge made of a leaf spring or the like is provided. By being urged toward the outer peripheral side of the tool via this, it is mounted so that it can come and go freely. Here, this cutting edge chip is formed in a substantially equilateral triangular flat plate shape, and an opening cutting blade is formed on each of two sides intersecting the corners of the triangular surface which is a rake face. The rake face is oriented in the tool rotation direction and one of the corners is located on the outer peripheral side of the tool, and the opening cutting blade intersecting the corner faces the outer peripheral side of the tool front end and the outer peripheral side of the tool rear end to form a chevron. Is mounted so as to protrude from the outer periphery of the tool body.
[0003]
Therefore, according to such a drilling tool, a processing hole is formed in a work material by rotating the tool main body while rotating the tool body, and a peripheral edge of an opening of the processing hole is formed by the cutting edge. Since the cutting edge is cut by the opening cutting blade facing the outer peripheral side of the tool tip, the burr generated on the periphery of the opening can be scraped off, or the periphery of the opening can be chamfered. When the tool body is further advanced, the cutting edge tip is once immersed in the tool body so as to be pushed into the inner periphery of the machining hole of the work material, and then the machining hole penetrates and the cutting edge tip is subjected to the machining. When it comes out of the hole, it is urged by the cartridge and protrudes again to the outer periphery of the tool body. Deburring and chamfering of the peripheral edge can be performed.
[0004]
[Problems to be solved by the invention]
By the way, in such a drilling process in which a drilling tool is used to form a processing hole that penetrates a work material, the work material is prevented from flexing particularly when the thickness of the work material is small. A support material is arranged on the side (the forward direction of the tool body) through which the machining hole of the work material penetrates to support the work material. Here, in order to reliably prevent the bending of the work material, it is desirable that the support material is disposed at the position of the processing hole. However, when the support material is disposed in this manner, a drilling tool is required. When the material penetrates the work material, the support material is also pierced by the cutting edge of the drilling tool, and a machining hole reaching the support material from the work material is formed. For this reason, as the material of the support material, a material softer than the work material is used in order to reduce the load on the cutting edge of the drilling tool when the support material is drilled, and is usually used. Wood is used because it is inexpensive, easily available, and easy to dispose after it has been drilled. If the work material is steel, soft metals such as aluminum are supported. It is used as a material.
[0005]
However, when the support material is disposed at the position of the processing hole in the work material and the drilling process is performed to penetrate the work material, the above-described conventional drilling tool uses the processing hole formed in the work material. Even if the cutting edge tip comes out of the tool, it is pushed into the machining hole formed in the support material and the cutting edge tip remains immersed in the tool body. There is a problem that it is not possible to cut the periphery of the opening on the through side of the material processing hole. In particular, in the drilling tool described in the above-mentioned publication, the corner of the cutting edge tip protruding to the outer peripheral side of the tool has a negative side in the tool rotation direction in order to prevent the work material from biting or scratching the inner peripheral surface of the processing hole. The flank of the cutting blade and the positive flank on the rear side in the tool rotation direction, and the flank of the negative flank and the positive flank, and the rake face of the negative flank and the opening cutting blade connected thereto. Are formed so as to be continuous with each other in a convex arc shape, and therefore, since this corner portion only comes into sliding contact with the inner periphery of the processing hole of the support material smoothly, Until the drilling tool is pulled out of the work hole in the work material, the cutting edge tip does not protrude to the outer peripheral side of the tool, and it is impossible to perform cutting with the opening cutting blade facing the outer peripheral side of the tool rear end. Become.
[0006]
The present invention has been made in view of such circumstances, and even when the support material is arranged as described above, a hole capable of cutting the periphery of the opening on the through side of the processing hole of the work material. It is an object to provide a drilling tool and a drilling method.
[0007]
[Means for Solving the Problems]
In order to solve the above problems and achieve such an object, a drilling tool according to the present invention includes a tool body having a cutting edge at a tip thereof, and a cutting tool provided on an outer periphery of a tip portion of the tool body so as to be able to protrude and retract. A drilling tool, comprising: a blade tip; and a cutting tool for cutting a peripheral edge of an opening of a processing hole formed in a work material by the cutting blade with an opening cutting blade formed in the cutting blade tip. In the insert, a cutting blade for diameter expansion is formed on the outer peripheral side of the tool of the opening cutting blade, and when the cutting blade tip is in a processing hole of the work material, the cutting blade for diameter expansion is outside the cutting blade. In a state where the cutting edge tip does not protrude to the outer peripheral side of the tool than the diameter and the cutting edge tip comes out of the machining hole, the cutting blade for expanding the diameter protrudes to the outer peripheral side of the tool beyond the outer diameter of the cutting edge to cover the tool. Insert the cutting edge tip above the tool so that the support material that supports the Characterized by being resiliently biased to the side.
[0008]
Further, the hole drilling method of the present invention uses such a drilling tool including a tool body having a cutting edge at the tip and a cutting edge tip provided on the outer periphery of the tip of the tool body so as to be able to protrude and retract. A drilling method for cutting the periphery of an opening of a processing hole drilled in a work material by the cutting blade with an opening cutting blade formed in the cutting blade tip, wherein the work material is While supported by the support material, the cutting blade tip is formed with a cutting blade for diameter expansion on the outer peripheral side of the tool of the opening cutting blade, the tool body is advanced, and the work material is penetrated by the cutting blade. And forming a machining hole reaching the support material, and projecting the diameter-enlarging cutting blade toward the outer periphery of the tool with respect to the outer diameter of the cutting blade when the cutting edge tip comes out of the machining hole of the work material. Then, the above-mentioned support material is After cutting and expanding the processing hole of the support material, the tool body is retracted, and the peripheral edge of the through-side opening of the processing hole of the work material is cut by the opening cutting blade. And
[0009]
Therefore, according to the drilling tool and the drilling method of the above-described configuration, since the diameter-enlarging cutting blade is formed on the cutting edge tip, when the cutting edge tip comes out of the processing hole of the work material, The diameter-enlarging cutting blade protrudes beyond the outer diameter of the cutting edge at the tip of the tool body toward the outer periphery of the tool to cut the support material that supports the work material, and enlarges the inner diameter of a processing hole formed in the support material. Since the diameter and the cutting edge of the cutting edge tip also protrude toward the outer peripheral side of the tool, by retracting the tool body from this state, the periphery of the through-side opening of the processing hole of the work material by the above-mentioned cutting edge is cut by the opening cutting blade. Can be cut. On the other hand, when the cutting edge tip is in the machining hole of the work material, the diameter-enlarging cutting blade does not protrude toward the outer peripheral side of the tool from the outer diameter of the cutting blade. It is possible to prevent the diameter-enlarging cutting blade from penetrating into the inner peripheral surface of the processed hole, and to prevent the inner peripheral surface of the processed hole from being damaged by the enlarged diameter cutting blade.
[0010]
Here, for example, when the work material is a steel material and the support material is wood or an aluminum material, as described above, when the cutting edge tip is in the processing hole of the work material, the cutting blade for diameter expansion is the cutting edge. The outer diameter of the cutting edge does not protrude to the outer peripheral side of the tool, and in a state where the cutting edge tip comes out of the machining hole, the cutting blade for diameter expansion protrudes to the outer peripheral side of the tool than the outer diameter of the cutting edge. In order to cut the support material, it is desirable to set an urging pressure (urging force) for elastically urging the cutting edge tip to the outer peripheral side of the tool in a range of 0.5 to 10 kg. That is, when the biasing pressure is higher than the above range, the cutting blade for diameter enlargement may cut into the inner peripheral surface of the machined hole of the work material, or may be damaged, while the biasing pressure is lower than the above range. Then, it may be difficult to cut the support material by the cutting blade for diameter expansion. Further, in order to more reliably prevent the cutting blade for diameter enlargement from biting into the inner periphery of the processing hole of the work material, the outer peripheral flank connected to the cutting blade for diameter expansion, When it is in the machining hole, it slides on the inner periphery of the machining hole, and in a state where the cutting edge tip comes out of the machining hole and protrudes to the outer periphery of the tool, a positive relief angle is given to the cutting blade for diameter enlargement. It is desirable to set.
[0011]
On the other hand, in the portion where the diameter-enlarging cutting blade and the opening-side cutting blade intersect with each other in the cutting edge tip, this portion is chamfered in a straight line crossing the diameter-enlarging cutting blade and the opening-side cutting blade at an obtuse angle. It is desirable to form a chamfered portion by chamfering or by beveling in a curved shape that is smoothly connected to both cutting blades, so that when the cutting edge tip is inserted into the machined hole of the work material, In addition, the cutting edge tip can be smoothly immersed in the tool main body, and it is possible to prevent chipping or the like at a portion where the diameter-enhancing cutting blade and the opening-side cutting blade intersect. Since the opening cutting blade is shortened by an amount, the chamfer width can be adjusted when chamfering the periphery of the processing hole of the work material. Support material surely under pressure It is possible to increase the diameter of the machined hole. Further, when such a configuration is adopted, by honing at least the chamfered portion, a portion where the diameter-enlarging cutting blade and the opening-side cutting blade intersect, that is, a defect or the like in the chamfered portion is reduced. It is possible to reliably prevent it.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 6 show an embodiment of a drilling tool according to the present invention. In this embodiment, the tool main body 1 has a substantially cylindrical outer shape, and a pair of outer circumferential ends of the tool main body 1 are twisted rearward in the tool rotation direction T toward the tool rear end side around the axis O of the tool main body 1. Are formed so as to open toward the tool tip and extend to the rear end side, and are formed at the tips of the wall faces of the chip discharge grooves 2 facing the tool rotation direction T side. A tip 4 made of a hard material such as a cemented carbide is brazed to the tip mounting seat 3, and a cutting edge 5 for forming a machining hole in a work material is formed at the tip of the tip 4. A supply hole 6 for cutting oil or the like is formed in the tool main body 1 from the rear end side of the tool toward the front end side along the axis O. The supply hole 6 branches into two at the front end side of the tool. Each of the cutting edges 5 and 5 has an opening at the tip flank 7 connected to the tool rotation direction T rear side.
[0013]
In the outer periphery of the leading end of the tool body 1, one of the leading flank surfaces 7 is formed so as to extend from one of the supply holes 6 opening in the leading flank 7 toward the outer periphery of the tool. A groove 9 is formed in one land 8 of the tool main body 1 which is open and communicates with the front end flank surface 7 and extends parallel to the axis O toward the tool rear end side. The cutting edge tip 11 is attached via the. Here, in the present embodiment, the cartridge 10 is mounted on the base 10A fixed to the bottom of the groove 9 as shown in FIGS. The accommodated movable arm 10B is rotatably mounted via a pin 10C, and a spring (coil spring) is interposed between the movable arm 10B and the base 10A as a biasing member 10D. Thereby, the cutting blade tip 11 is elastically urged toward the outer peripheral side of the tool together with the movable arm 10B, so that the cutting edge tip 11 is allowed to protrude and retract on the outer periphery of the tool body 1. The urging pressure of the urging member 10D, that is, the spring pressure of the coil spring is set in the range of 0.5 to 10 kg in the present embodiment.
[0014]
Further, the cutting edge tip 11 in the present embodiment is also formed of a hard material such as a cemented carbide and has a substantially equilateral triangular plate shape as shown in FIGS. 5 and 6. A rake face 11A and an outer peripheral face are flank faces 11B, and a mounting hole 11C is formed at the center of the rake face 11A so as to penetrate the cutting edge chip 11 in its thickness direction. Here, the equilateral triangular surface, which is the rake face 11A of the cutting edge chip 11, is cut out so that its three corners are parallel to the sides facing the respective corners. Strictly speaking, the blade tip 11 has an oblique hexagonal flat plate shape as shown in FIG. And the cutting blade 12 for diameter expansion is respectively formed in the notched corner part of this rake face 11A, and the edge of the said rake face 11A connected to both ends of this cutting blade 12 for diameter expansion has Opening cutting blades 13, 13 are formed respectively.
[0015]
Note that, of the rake face 11A, an isosceles trapezoidal portion surrounded by the diameter-enlarging cutting blade 12 and the opening-side cutting blades 13 and 13 at the respective corners, as shown in FIG. As it goes from the blade 12 toward the mounting hole 11C at the center of the rake face 11A, it is inclined at a constant gradient toward the seating face 11D opposite to the rake face 11A, and is formed so as to be cut into a concave arc shape. I have. In addition, a portion of the flank 11B that is continuous with the cutting blade 12 for diameter enlargement is formed so as to be parallel to the thickness direction of the cutting edge tip 11, and the clearance angle of the cutting blade 12 for diameter expansion. Is set to be 0 °, while the portion connected to the opening cutting blade 13 is formed so as to be inclined toward the mounting hole 11C side as it goes toward the seating surface 11D side. It is set so that a positive clearance angle is given.
[0016]
On the other hand, at the tip of the movable arm 10B of the cartridge 10 on which such a cutting edge chip 11 is mounted, a bottom surface facing the tool rotation direction T side with the cartridge 10 attached to the concave groove 9 of the tool main body 1. 14A, a wall 14B rising from the periphery of the bottom surface 14A and facing the outer peripheral side of the tool, and a wall surface 14C intersecting the wall surface 14B at substantially 60 ° and facing the inner peripheral side of the tool tip. Is formed. A screw hole (not shown) is formed in the bottom surface 14A. The cutting edge tip 11 directs the rake face 11A to the tool rotation direction T side and makes the seating face 11D adhere to the bottom face 14A, and the cutting blade 12 for the diameter enlargement at one corner of the rake face 11A. Projecting toward the outer peripheral side of the tool, the flank 11B continuous with the side ridge of the rake face 11A opposite to the cutting blade 12 for diameter expansion is brought into contact with the wall surface 14B, and in this state, the tool rear end A part of the flank 11B facing the outer peripheral side is brought into contact with the wall surface 14C to be seated on the chip mounting seat 14, and the clamp screw 15 inserted into the mounting hole 11C is further screwed into the screw hole to thereby mount the cartridge. 10 is attached.
[0017]
Next, in the case where the drilling tool having the above-described configuration is used to perform drilling on the work material W supported by the support material S to form a machined hole Hw penetrating the work material W. One embodiment of the drilling method according to the present invention will be described with reference to schematic diagrams shown in FIGS. In the present embodiment, the work material W is a steel material, and as the support material S, wood (linkwood) softer than the work material is used. And this support material S is arrange | positioned in the position which the said processing hole Hw of the back side of the workpiece W penetrates.
[0018]
First, when the tool main body 1 is advanced toward the workpiece W while rotating the tool main body 1 around the axis O in the tool rotation direction T, the cutting edges 5 and 5 at the forefront of the tool main body 1 bite into the workpiece W. , The formation of the processing hole Hw starts. When the cutting edge tip 11 reaches the work material W, an opening on the drilling tool insertion side (the front side of the work material W; the upper side of the work material W in FIGS. 7 to 11) of the machining hole Hw. Cutting of the peripheral edge E1 is performed. That is, in the cutting edge tip 11 projecting to the outer periphery of the tip end portion of the tool body 1 of the drilling tool, the cutting blade 12 for diameter enlargement is arranged parallel to the axis O and most protrudes toward the outer periphery of the tool. Of the opening cutting blades 13 and 13 connected to both ends of the diameter-enlarging cutting blade 12, the opening cutting blade 13 on the tool tip side is arranged so as to be inclined toward the tool inner peripheral side toward the tool tip side. As a result, the cutting edge 13 of the opening on the tool tip side digs into the peripheral edge E1 of the opening as shown in FIG. 7, so that the burr generated on the peripheral edge E1 of the opening is cut off or the peripheral edge E1 of the opening is removed. May be chamfered into a tapered surface.
[0019]
Next, when the tool body 1 is further advanced, the inclined cutting edge 13 is guided by the opening peripheral edge E1 so that the cutting edge chip 11 is attached to the movable arm 10B of the cartridge 10 by the urging member 10D. As shown in FIG. 8, the cutting edge tip 11 is inserted into the machining hole Hw, and the diameter-enlarging cutting blade 12 is pushed into the inner peripheral surface of the machining hole Hw. It will be in contact. At this time, in this embodiment, since the urging pressure by the urging member 10D is set in the range of 0.5 to 10 kg, it is difficult for the diameter-enlarging cutting blade 12 to bite into the inner peripheral surface of the machining hole Hw. Instead, the diameter-enlarging cutting blade 12 simply rotates around the axis O while sliding on the inner peripheral surface of the processing hole Hw.
[0020]
When the tool body 1 is further advanced in this way, the cutting blades 5, 5 reach the back surface of the work material W and the machining hole Hw penetrates the work material W. In addition, a processing hole Hs having the same diameter as the processing hole Hw of the workpiece W is formed on the support material S arranged at the position of the processing hole Hw by the cutting edges 5 and 5. When the cutting edge tip 11 comes out of the opening edge E2 on the penetrating side of the machining hole Hw (the back side of the work material W; the lower side of the work material W in FIGS. 7 to 11), the urging member Since the urging pressure of 10D is set in the range of 0.5 to 10 kg, the cutting edge tip 11 projects again to the tool outer peripheral side by this urging force, and the cutting blade 12 for diameter expansion is formed on the support material S. As shown in FIG. 9, cutting is performed so as to increase the inner diameter of the processing hole Hs by digging into the inner peripheral surface of the processing hole Hs.
[0021]
However, when the tool main body 1 is retracted from here, the opening peripheral edge E2 on the penetrating side of the machining hole Hw of the work material is cut by the opening cutting blade 13 connected to the tool rear end side of the diameter-enlarging cutting blade 12. Is done. That is, the opening cutting blade 13 on the rear end side of the tool is inclined so as to move toward the inner peripheral side of the tool toward the rear end side of the tool, opposite to the opening cutting blade 13 on the front end side of the tool. As the main body 1 is retracted, the cutting edge 13 of the opening on the rear end side of the tool cuts into the peripheral edge E2 of the opening as shown in FIG. 10, so that the burr generated on the peripheral edge E2 of the opening is scraped off, or The peripheral edge E2 of the opening is chamfered into a tapered surface.
[0022]
Then, when the tool main body 1 is further retracted, the opening cutting blade 13 on the inclined tool rear end side is guided by the opening peripheral edge E2 on the penetrating side, and the cutting blade tip 11 is similarly moved as described above. The movable arm 10B is again pushed into the inner peripheral side of the tool against the urging force of the urging member 10D, and the cutting edge tip 11 is inserted into the machining hole Hw as shown in FIG. Is in contact with the inner peripheral surface of the processing hole Hw. Also at this time, the diameter-enlarging cutting blade 12 does not bite into the inner peripheral surface of the processing hole Hw. Therefore, by removing the tool body 1 from the machining hole Hw as it is, the peripheral edges E1 and E2 of the insertion side and the penetration side thereof are cut and deburred or chamfered on the workpiece W as shown in FIG. The processed hole Hw is formed.
[0023]
As described above, in the drilling tool having the above-described configuration and the drilling method using the drilling tool, the cutting blade 12 for expanding the diameter is formed on the cutting edge tip 11, and the cutting edge tip 11 is The cutting blade 12 for diameter expansion projects from the outer diameter of the cutting blades 5 and 5 toward the outer periphery of the tool in a state where the cutting blade 12 comes out of the processing hole Hw of the material W so as to cut the support material S which supports the workpiece W. Since the cutting edge tip 11 is elastically urged toward the outer peripheral side of the tool by the urging member 10D, the diameter of the cutting edge tip 11 protruding from the machining hole Hw of the workpiece W to the outer peripheral side of the tool is increased. The cutting blade 12 for use digs into a processing hole Hs formed in the support material S and expands the diameter. Therefore, when the tool main body 1 is retracted, the cutting edge tip 11 projects in the machining hole Hs thus enlarged, and the opening cutting edge 13 facing the tool rear end side of the cutting edge tip 11. This makes it possible to cut the opening edge E2 on the through side of the processing hole Hw of the work material W, and as described above, the processing hole Hw on which the opening edges E1 and E2 on the insertion side and the penetration side are cut. Can be formed on the work material W.
[0024]
On the other hand, when the cutting edge tip 11 is inserted into the processing hole Hw of the work material W, the cutting blade 12 for diameter expansion contacts the inner peripheral surface of the processing hole Hw. The cutting edge 12 is energized so as not to protrude beyond the outer diameter of the cutting edges 5 and 5 at the tip of the tool. Since the inner peripheral surface of the processing hole Hw is not cut into the processing hole Hw, the inner diameter of the processing hole Hw is unnecessarily expanded by the diameter-enlargement cutting blade 12 or the inner diameter of the processing hole Hw is unnecessarily increased. It is possible to prevent the inner peripheral surface from being damaged and the finished surface accuracy from being impaired. In addition, according to the drilling tool and the drilling method having the above-described configuration, the cutting edge tip 11 rotates around the axis O while abutting on the inner peripheral surface of the processing hole Hw of the workpiece W as described above. By doing so, a so-called burnishing effect is generated, and the inner peripheral surface of the machined hole Hw is finished smoothly, so that it is possible to obtain an effect that rather good surface finish accuracy can be obtained.
[0025]
Here, in the drilling tool of the present embodiment, while the work material W is a steel material and the support material S is wood, the urging member 10D that urges the cutting edge tip 11 toward the tool outer peripheral side. The biasing pressure is set in the range of 0.5 to 10 kg, so that the above-described drilling method can be performed by making the cutting tip 11 protrude and retract more reliably inside and outside the processing hole Hw. That is, if the urging pressure by the urging member 10D exceeds the above range, the cutting edge tip 11 will be pressed too strongly against the inner peripheral surface of the processing hole Hw of the workpiece W, and the diameter-enlarging cutting blade 12 may cut into the inner peripheral surface to increase the diameter of the processing hole Hw, or may damage the inner peripheral surface to deteriorate the finished surface roughness.
[0026]
On the other hand, if the biasing pressure is lower than the above range, the cutting edge tip 11 does not sufficiently project to the outer peripheral side of the tool when it comes out of the processing hole Hw, and the diameter-enlarging cutting blade 12 cuts into the support material S. As a result, it becomes difficult to increase the diameter of the processing hole Hs of the support material S, and therefore, there is a possibility that the peripheral edge E2 of the opening portion on the through side of the processing hole Hw of the work material W may not be cut. In the present embodiment, when the support material S is made of wood, the biasing pressure is set in the above range. However, even when the support material S is made of a metal material softer than the work material W such as an aluminum material, for example, The biasing pressure may be set in a substantially similar range.
[0027]
Further, in the drilling tool of the present embodiment, the cutting edge tip 11 has a substantially triangular flat plate shape, and the diameter-enlarging cutting blade 12 is formed at each corner of the triangular surface which is a rake face 11A. Opening cutting blades 13 and 13 are formed at both ends of the diameter-enlarging cutting blade 12, and these opening cutting blades 13 and 13 are suitable for deburring and chamfer cutting of the opening peripheral edges E1 and E2. An inclination can be provided, and one cutting edge tip 11 can be used three times. Further, in the cutting blade tip 11 of the present embodiment, the corner portion of the rake face 11 </ b> A surrounded by the diameter-enlarging cutting blade 12 and the opening-side cutting blades 13, 13 is separated from the diameter-enlarging cutting blade 12. It is formed so as to incline at a constant gradient toward the seating surface 11D opposite to the rake face 11A as it goes toward the mounting hole 11C, and then to be cut into a concave arc shape. The advantage is obtained that the rake angle in the radial direction is set large on the regular angle side to give sharp sharpness, and the biting of the diameter-enlarging cutting blade 12 into the processing hole Hs of the support material S and the improvement of the machinability can be achieved. .
[0028]
In the present embodiment, the rake face 11 </ b> A surrounded by the diameter-enlarging cutting blade 12 and the opening-side cutting blades 13, 13 of the cutting blade tip 11 is formed so as to be inclined. Like the cutting edge tip 21 shown in FIGS. 13 and 14, the rake face 11A itself is formed parallel to the seating face 11D without being inclined, and the cutting blade 12 for diameter enlargement and the cutting of the opening of the rake face 11A are formed. A groove-shaped chip breaker 22 may be formed in a portion surrounded by the blades 13, 13 along the diameter-enlarging cutting blade 12 and the opening-side cutting blades 13, 13. In this case, the chip breaker 22 sets the rake angle of the diameter-enlarging cutting blade 12 and the opening-side cutting blades 13, 13 to be substantially larger on the regular angle side. Can be obtained. However, in the cutting edge tips shown below, starting from FIGS. 13 and 14, the same reference numerals are assigned to portions common to the cutting edge tips 11 shown in FIGS. 5 and 6, and description thereof will be omitted.
[0029]
On the other hand, in these cutting edge chips 11 and 21, a part of the flank 11B arranged around the rake face 11A and connected to the cutting blade 12 for diameter enlargement has a clearance angle of the cutting blade 12 for diameter expansion. Is formed in parallel with the thickness direction of the cutting edge chips 11 and 21 so that the opening cutting blade 13 is provided with a positive clearance angle. Although it is formed so as to be inclined toward the mounting hole 11C as it goes to the seating surface 11D side, it is possible to more reliably prevent the cutting blade 12 for enlarging the diameter-enlargement into the machining hole Hw of the work material W. To prevent this, as shown in the cutting edge tip 31 shown in FIG. 15 and FIG. Convex arc surface with radius of curvature equal to inner radius of machined hole Hw of material W When the cutting edge tip 31 is in the machining hole Hw of the work material W, the cutting edge tip 31 slides into the inner peripheral surface of the machining hole Hw, and the cutting edge tip 31 comes out of the machining hole Hw. It is desirable to set the diameter-enlarging cutting blade 12 to give a positive relief angle when it protrudes toward the outer peripheral side of the tool.
[0030]
That is, according to the drilling tool equipped with the cutting edge tip 31 having such a configuration, as shown in FIG. 17, when the cutting edge tip 31 is in the machining hole Hw of the work material, the outer peripheral flank 32 is entirely formed. Since the cutting blade 12 for diameter enlargement is securely prevented from biting into the inner peripheral surface of the processing hole Hw, the cutting blade 12 for diameter enlargement is reliably prevented. On the other hand, in the drilling tool having the above-described configuration, for example, the direction in which the cutting edge tip 31 appears and retracts is set such that the diameter-enlarging cutting blade 12 extends and retracts in the radial direction with respect to the axis O of the tool body 1. In this case, when the cutting edge tip 31 escapes from the machining hole Hw of the workpiece W and projects to the tool outer peripheral side, a positive clearance angle is given to the outer peripheral flank 32 as shown in FIG. Since a clearance can be secured between the outer peripheral flank 32 and the inner peripheral surface of the processing hole Hs whose diameter has been increased by the diameter-enlarging cutting blade 12, the processing hole Hs can be efficiently expanded with a small resistance. It is possible to reliably cut the opening peripheral edge E2 on the through side of the processing hole Hw of the workpiece W.
[0031]
Further, as in a cutting edge tip 41 partially shown in FIGS. 18 and 19, a flank 11B disposed around the rake face 11A and a portion connected to the diameter-enlarging cutting blade 12 and the opening cutting portion are formed. A flat chamfered surface 42 is formed at the intersection ridge line portion with the portion connected to the blades 13, 13. Both the cutting blade 12 and the opening-side cutting blades 13, 13 are formed with a straight chamfered portion 43 that intersects at an obtuse angle, or as in the case of the cutting blade tip 51 partially shown in FIGS. A convexly curved chamfered surface 52 which is curved in the circumferential direction of the rake face 11A is formed at the intersection ridge line portion of the flank 11B, and the diameter-enlargement cutting blade 12 and the opening-side cutting blades 13, 13 intersect. The cutting blades 12 for diameter enlargement To or forms a convex curved chamfer 53 of the circular arc or the like connected to smoothly both fine opening cutting blades 13, 13 is desirable.
[0032]
However, when such a configuration is adopted, the opening edge E1 on the insertion side of the machining hole Hw of the workpiece W is cut by the opening cutting blade 13 on the tool tip side of the cutting edge tips 41 and 51. After that, when the cutting blade tips 41, 51 are inserted into the machining hole Hw with the advance of the tool body 1, or when the opening cutting blade 13 on the tool rear end side opens the machining hole Hw on the penetration side. After the peripheral edge E2 is cut, when the cutting blade tips 41, 51 are inserted into the machining holes Hw with the retraction of the tool body 1, the cutting blade tips 41, 51 are guided to the chamfered portions 43, 53. As a result, the tool is more smoothly pushed into the inner peripheral side of the tool and is immersed in the concave groove 9 of the tool body 1. Are crossed to these opening edges E1 and E2. The situation in or cause Paste or, or defects such as enlarged diameter for the cutting edge 12 and opening the cutting edge 13, 13 of the wound applied can be prevented.
[0033]
Further, by forming such chamfered portions 43, 53 on the cutting edge tips 41, 51, the diameter-enlarging cutting blade 12 and the opening-side cutting blades 13, 13 directly intersect without providing the chamfered portions 43, 53. As compared with the case where the cutting blade 13 is used, the cutting edge length of the diameter-enlarging cutting blade 12 and the opening-side cutting blades 13 and 13 can be shortened. While the chamfering width at the time of chamfering the peripheral edges E1 and E2 can be adjusted, the support member S can be reliably cut even if the urging pressure by the urging member 10D is small in the diameter-enlarging cutting blade 12. There is also obtained an advantage that the diameter of the processing hole Hs can be increased.
[0034]
Further, when such chamfered portions 43 and 53 are formed, the chamfer formed linearly on the cutting edge tip 41 like a cutting edge tip 61 partially shown in FIGS. The portion 43 is honed to form a honing surface 62 that intersects the chamfer surface 42 and the rake surface 11A at an obtuse angle, or like a cutting edge chip 71 partially shown in FIGS. 24 and 25. It is desirable to perform honing on the chamfered portion 53 formed in a convex curve shape on the chip 51 to form a honing surface 72 that intersects the chamfered surface 52 and the rake surface 11A at an obtuse angle. By applying, it is possible to more reliably prevent a portion where the diameter-enlarging cutting blade 12 intersects with the opening-side cutting blades 13, that is, the chamfered portions 43 and 53. The ability. In addition, if such honing is performed not only on the chamfered portions 43 and 53 but also on the cutting blades 12 for diameter expansion and the cutting blades 13 for the opening, the cutting blades 12 for diameter expansion and the cutting blades 13 for the opening may be used. Can be prevented from being lost or chipped.
[0035]
【The invention's effect】
As described above, according to the drilling tool and the drilling method of the present invention, even if the support material that supports the work material is at the position of the work hole formed in the work material, The peripheral edge of the opening on the through side can be reliably cut and deburred or chamfered, so that more efficient drilling can be promoted.
[Brief description of the drawings]
FIG. 1 is a side view of a tip end portion of a tool main body 1 showing an embodiment of a drilling tool according to the present invention.
FIG. 2 is a front view of the embodiment shown in FIG. 1 as viewed from a tool tip side.
FIG. 3 is a side view partially showing the vicinity of the cutting edge tip 11 of the embodiment shown in FIG. 1 when viewed in the Z direction in FIG. 2;
FIG. 4 is a side view showing the cartridge 10 and the cutting blade tip 11 of the embodiment shown in FIG.
FIG. 5 is a plan view of the cutting edge tip 11 of the embodiment shown in FIG.
6 is a sectional view of the cutting edge tip 11 shown in FIG.
7 is a diagram showing an initial state of an embodiment of the drilling method of the present invention using the drilling tool of the embodiment shown in FIG. 1;
FIG. 8 is a diagram showing a state next to FIG. 7;
FIG. 9 is a diagram showing a state next to FIG. 8;
FIG. 10 is a diagram showing a state next to FIG. 9;
FIG. 11 is a diagram showing a state next to FIG. 10;
FIG. 12 is a diagram showing a state next to FIG. 11;
FIG. 13 is a plan view of a cutting edge tip 21 according to a modification of the embodiment of the drilling tool of the present invention.
14 is a sectional view of the cutting edge tip 21 shown in FIG.
FIG. 15 is a plan view of a cutting edge tip 31 of a modified example according to the embodiment of the drilling tool of the present invention.
16 is a sectional view of the cutting edge tip 31 shown in FIG.
FIG. 17 is a cross-sectional view orthogonal to the axis O showing a case in which a boring tool is mounted with the cutting edge tip 31 shown in FIG.
FIG. 18 is a partial plan view of a cutting edge tip 41 of a modification according to the embodiment of the drilling tool of the present invention.
19 is a partial side view of the cutting edge tip 41 shown in FIG.
FIG. 20 is a partial plan view of a cutting edge tip 51 of a modification according to the embodiment of the drilling tool of the present invention.
21 is a partial side view of the cutting edge tip 51 shown in FIG.
FIG. 22 is a partial plan view of a cutting edge tip 61 of a modification according to the embodiment of the drilling tool of the present invention.
23 is a partial side view of the cutting edge tip 61 shown in FIG.
FIG. 24 is a partial plan view of a cutting edge tip 71 of a modification according to the embodiment of the drilling tool of the present invention.
FIG. 25 is a partial side view of the cutting edge tip 71 shown in FIG. 24;
[Explanation of symbols]
1 Tool body
5 Cutting blade
10 cartridges
10D biasing member
11, 21, 31, 41, 51, 61, 71 Cutting edge tip
11A rake face
11B Flank
12 Cutting blade for diameter expansion
13 Opening cutting blade
22 chip breaker
32 Outer flank
43,53 chamfer
62, 72 Honing surface
W Work material
S Support material
Hw Work hole of work material W
Processing hole of Hs support material S
E1 Periphery of the opening on the insertion side of the processing hole Hw
E2 Peripheral edge of opening on the through side of processing hole Hw
O Center axis of tool body 1
T Tool rotation direction

Claims

A tool body having a cutting edge at a tip thereof, and a cutting blade tip provided on the outer periphery of the tip portion of the tool body so as to be able to protrude and retract, and a peripheral edge of an opening of a processing hole formed in a work material by the cutting blade. A drilling tool that is cut by an opening cutting blade formed in the cutting edge tip, wherein the cutting edge tip has a cutting blade for diameter expansion formed on a tool outer peripheral side of the opening cutting blade, When the cutting edge tip is in the processing hole of the work material, the diameter-enlarging cutting blade does not protrude to the outer peripheral side of the tool than the outer diameter of the cutting edge, and the cutting edge tip is The cutting edge tip is elastically moved toward the outer peripheral side of the tool so that the cutting blade for diameter expansion protrudes to the outer peripheral side of the tool from the outer diameter of the cutting edge and cuts the support material that supports the work material in the pulled-out state. A drilling tool characterized in that it is biased in a specific way.

The drilling tool according to claim 1, wherein a biasing pressure for elastically biasing the cutting edge tip toward a tool outer peripheral side is set in a range of 0.5 to 10 kg.

The outer peripheral flank connected to the diameter-enlarging cutting blade is in sliding contact with the inner periphery of the machining hole when the cutting edge tip is in the machining hole of the work material, and the cutting edge tip comes out of the machining hole. The drilling tool according to claim 1, wherein the cutting tool is set so as to give a positive relief angle to the diameter-enlarging cutting blade when the cutting tool protrudes toward the outer peripheral side of the tool.

The hole according to any one of claims 1 to 3, wherein a chamfered portion is formed at a portion where the diameter-enlarging cutting blade and the opening-side cutting blade intersect in the cutting blade tip. Dawning tool.

The drilling tool according to claim 4, wherein at least the chamfered portion is honed.

Using a drilling tool provided with a tool body having a cutting edge at the tip and a cutting blade tip provided on the outer periphery of the tip of the tool body so as to be able to protrude and retract, machining performed on the work material by the cutting blade A drilling method for cutting a periphery of an opening of a hole by an opening cutting blade formed in the cutting edge tip, wherein the work material is supported by a support material rather than the work material, In the cutting edge tip, a cutting blade for diameter expansion is formed on the outer peripheral side of the tool of the opening cutting blade, the tool body is advanced, and the cutting blade penetrates the work material and reaches the support material. While forming a hole, the cutting blade tip is protruded from the outer diameter of the cutting blade to the outer peripheral side of the tool when the cutting tip comes out of the processing hole of the work material, and the support material is cut. After expanding the processing hole of the support material with Retracting the tool body, drilling method characterized by cutting the periphery of the through side opening of the machined hole in the workpiece by the opening cutting blades.