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JP3812480B2 - Throw-away drill - Google Patents

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Publication number
JP3812480B2
JP3812480B2 JP2002096740A JP2002096740A JP3812480B2 JP 3812480 B2 JP3812480 B2 JP 3812480B2 JP 2002096740 A JP2002096740 A JP 2002096740A JP 2002096740 A JP2002096740 A JP 2002096740A JP 3812480 B2 JP3812480 B2 JP 3812480B2
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cutting head
tool body
head portion
shaft
end surface
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JP2002096740A
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JP2003291019A (en
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正治 滝口
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Mitsubishi Materials Corp
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Mitsubishi Materials Corp
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Description

【0001】
【発明の属する技術分野】
本発明は、切刃を有する切削ヘッド部を工具本体に交換可能に装着できるようにしたスローアウェイ式ドリルに関する。
【0002】
【従来の技術】
従来、切刃を有する切削ヘッド部を工具本体に交換可能に装着できるようにしたスローアウェイ式ドリルとして、例えば実用新案登録第3054444号公報に記載されたものがある。
このスローアウェイ式ドリルは、ドリルの先端側領域からなる切削ヘッド部と工具シャンクの相互の連結部において、工具シャンクに弾性スリットを設け、弾性スリットの両側に対向する連結用の一対の凹面状固定壁とトルクを切削ヘッド部に伝達する一対のトルク伝導壁とをそれぞれ形成し、切削ヘッド部には工具シャンクの固定壁に係合する一対の凸面状固定壁と、工具シャンクのトルク伝導壁に嵌合する一対のトルク伝導壁とを有している。対向する凹面状固定壁の最小の間隔は凸面状固定壁の幅より広く設定されている。
【0003】
そして工具シャンクに切削ヘッド部を連結するに当たって、工具シャンクの凹面状固定壁の間隙に切削ヘッド部の凸面状固定壁を通過させるようにして両固定壁を同軸で直交させ、次に切削ヘッド部を工具本体の回転方向と逆方向に回転させると、工具シャンク部のトルク伝導壁に切削ヘッド部のトルク伝導壁が当接すると共に凸面状固定壁と凹面状固定壁とが結合する。両固定壁の結合は工具本体の弾性スリットを弾性変形させて広げつつ行い、これによって切削ヘッド部と工具シャンクとが弾性的に結合されることになる。
【0004】
【発明が解決しようとする課題】
しかしながら、このような構造では切削ヘッド部と工具シャンク部の結合は弾性スリットによる弾性的な結合でのみ行われるために、両者の結合力が小さく、孔あけ加工時に大きな切削負荷がかかると、切削ヘッド部がずれたり外れたりし易く、孔加工精度が低下したり、工具破損の原因になり易いために加工コストの増大につながるという問題がある。
本発明は、このような実情に鑑み、切削ヘッド部の着脱が容易で且つ堅固に固定できると共に、切削ヘッド部及び工具本体にかかる負担を軽減して破損を防止することができるスローアウェイ式ドリルを提供することを目的とする。
【0005】
【課題を解決するための手段】
上記課題を解決するために、本発明は、切刃が設けられた切削ヘッド部を工具本体に着脱可能に装着してなるスローアウェイ式ドリルにおいて、前記切削ヘッド部には嵌合部が設けられ、前記工具本体には前記嵌合部と嵌合可能な受け部が設けられ、前記嵌合部は、切削ヘッド部の基端面から工具本体側に軸線上で突出する軸部と、軸線を中心として回転対称に設けられ前記基端面から切削ヘッド部の先端面側に凹設される一対の段差部とを備え、前記切削ヘッド部の基端面から突出した前記軸部の軸先端面寄りの周面には軸先端面に向かって広がる係合面が形成され、該軸部における前記切削ヘッド部の基端面寄りの周面には前記軸線に平行または前記切削ヘッド部の基端面側に向かって拡がるように形成された芯出し周面が形成され、前記受け部は、工具本体の先端面からその基端側に設けられ前記軸部に嵌合する凹部と、前記先端面から切削ヘッド部側に凸設され前記各段差部に嵌合する一対の受け段部とを備え、前記凹部には、前記係合面に対応する挟持面と、前記芯出し周面に対応する整合面とが形成され、前記工具本体には、その先端部分を径方向で分割するスリットが設けられ、前記嵌合部と前記受け部とを嵌合させた状態で、前記係合面と挟持面との隙をS1、前記芯出し周面と整合面との隙をS2とすると、S1<S2とされ、前記スリットを貫通する締結ボルトを締め込むことによって、前記軸部を前記凹部で締め付けて前記工具本体に前記切削ヘッド部を固定することを特徴とする。
【0006】
このように構成することで、工具本体に切削ヘッド部を固定するに当たり、前記嵌合部と前記受け部とを嵌合させた状態で工具本体に締結ボルトを締め込むと、工具本体がスリットの間隙を縮小するように弾性変形し、嵌合部の軸部の係合面によって切削ヘッド部を工具本体側に引き込んで密着させると共に、軸部の芯出し周面によって高精度に芯出しを行う。そして、軸部を凹部で締め付けて工具本体に切削ヘッド部を堅固に固定することが可能となる。
【0007】
なお、前記芯出し周面が、前記切削ヘッド部の基端面側に向かって拡がるように形成されている場合には、切削ヘッド部の基端面に対する軸部の軸基端の周面の角度を鈍角として、軸基端の周囲の応力集中を軽減することが可能となる。
【0008】
そして、前記凹部には、前記係合面に対応する挟持面と、前記芯出し周面に対応する整合面とが形成され、前記係合面と挟持面との隙をS1、前記芯出し周面と整合面との隙をS2とすると、S1<S2であるように構成することで、軸部を凹部で締め付けた時に、先ず係合面と挟持面とが当接し、切削ヘッド部を工具本体側に引き込んだ状態で芯出し周面と整合面とが当接して芯出しを行うことが可能となる。
【0009】
また、前記工具本体には、前記締結ボルトを装着する挿通孔及びねじ部が形成され、前記挿通孔及びねじ部の一部が前記凹部内を通過するように設けられるとともに、前記軸部の軸先端面には、前記締結ボルトの逃げ部が形成されているように構成することで、締結ボルトの配設位置を工具本体の先端面側、つまりスリットの開放端側に近づけることが可能となる。
【0012】
【発明の実施の形態】
以下、本発明の実施の形態を図面と共に説明する。
図1は本発明に係るスローアウェイ式ドリルの側面図、図2はその平面図である。
図1に示すように、本実施の形態によるスローアウェイ式ドリル(以下、ドリルということがある)1は、工具本体2がシャンク部3と刃部4とからなる略棒状を呈しており、刃部4の先端には、テーパ状の先端面7に一対の切刃8を有するスローアウェイタイプの切削ヘッド部5が交換可能に装着されている。
刃部4の外周面4aには、2つの切屑排出溝6,6及びそれらに隣接するランド部10,10がドリル本体の回転軸線Oを中心に対向して回転対称に形成されており、回転軸線O回りにねじれている。
【0013】
工具本体2の内部には、回転軸線Oに沿って、好ましくは同軸上に、工具本体2の基端側(同図においては下方側)から切削ヘッド部5に向かって油孔28が形成されている。この油孔28は切削ヘッド部5に到達しない途中位置で複数(本実施の形態においては2つ)に分岐され、各分岐油孔28a,28aはそれぞれ外周側に延びて切削ヘッド部5近傍のランド部10,10外周面に設けられた油溝28b,28bに開口している。
【0014】
図2に示すように、切削ヘッド部5において、各切屑排出溝6,6の回転方向(図中矢印Rで示す)を向く先端側の壁面と先端面7との各交差稜線部に一対の切刃8,8が形成されている。
尚、凹面部5b,5bは前記油溝28b,28bの一部を構成しており、孔あけ加工時に切削部への直接給油を可能にしている。
上述の基本構成を備えたドリル1は、図1に示すように、スローアウェイタイプの切削ヘッド部5に設けられた後述する嵌合部14と、工具本体2に設けられた後述する受け部20とが嵌合することで相互に固着可能とされており、更に、工具本体2の受け部20を2分するように設けられたスリット26を締結ボルト30によって弾性変形させることで、切削ヘッド部5の嵌合部14を締め付けて工具本体2に切削ヘッド部5を堅固に固定している。
【0015】
図3は切削ヘッド部5の平面図、図4はその側面図である。
図3に示すように、切削ヘッド部5は、回転軸線Oの両側に回転対称に形成された一対のヘッドランド部10a,10aが設けられ、これらヘッドランド部10a,10aに隣接して略凹曲面状の一対の凹側面6a,6aが形成されている。 ヘッドランド部10a,10aは前記ランド部10,10の一部を構成しており、凹側面6a,6aは切屑排出溝6,6の一部を構成している。
先端面7は回転軸線Oを中心とした概略テーパ状に形成され、回転軸線O付近から径方向外側に延びる一対の前記切刃8,8と、各切刃8の回転方向後方に順次設けられた逃げ面11とシンニング面12とを有している。
尚、図中矢印Rは回転方向を示す。
【0016】
図4に示すように、切削ヘッド部5の先端面7の反対側の面(基端面5a)には、工具本体2と嵌合するための嵌合部14が設けられている。
この嵌合部14は、回転軸線Oと同軸上で基端面5aから工具本体2側に突出する軸部15を備えており、この軸部15のヘッドランド部10a,10a方向の外周部分であって、軸部15の軸先端面15a寄りの周面にはその軸先端面15a側に向かって広がる係合面16aが形成され、軸部15の基端面5a寄りの周面には回転軸線Oに平行な芯出し周面16bが形成されている。
そして、軸部15の軸先端面15aには、締結ボルト30の首下部分との干渉を避けるための逃げ部15bが凹設されている。
【0017】
また、嵌合部14は、基端面5aを先端面7側に切り欠いて形成される段差部18を備えている。
この段差部18は、駆動力を伝達するための径方向に延びる傾斜面18aと、その周方向両側に位置する肉厚部18b及び肉薄部18cとを有している。
ここで、図3に示すように、肉厚部18bは、肉薄部18cに対してドリル1の回転方向前方に位置している。また、段差部18はヘッドランド部10a,10aの裏面に一対設けられ、各々回転軸線Oの両側に180°回転対称に形成されている。尚、同図においては、図示都合上一方の段差部18のみに符号を付す。
更に、傾斜面18a、18aは、切削ヘッド部5の外周に沿う方向で、且つ、その外周側を回転方向に向けるように径方向に対して傾斜して形成されると共に、軸線方向に対する傾斜角θ1(図3における側面図に示す)が10°〜60°となるように傾斜して形成されている。
【0018】
図5は工具本体2の先端部分の平面図、図6(a)はその側面図、図6(b)は図6(a)における要部拡大図である。
図5に示すように、工具本体2の刃部4には、切屑排出溝6,6に隣接して、回転軸線Oの両側に回転対称に形成された一対の本体ランド部10b,10bが設けられており、この本体ランド部10b,10bはヘッドランド部10a,10aと共にランド部10,10を構成している。尚、図中矢印Rは回転方向を示す。
【0019】
図6(a)に示すように、工具本体2の先端面2aには、切削ヘッド部5を嵌合させるための受け部20が設けられている。
この受け部20は、工具本体2の先端面2aを工具本体2の基端側(同図においては下方側)に向けて切り欠いた凹部22を備えており、この凹部22の本体ランド部10b,10b方向の内周部分であって、凹部22の底面22a寄りの周面には前記係合面16aに対応する挟持面23aが形成され、凹部22の先端面2a寄りの周面には前記芯出し周面16bに対応する整合面23bが形成されている。
【0020】
ここで、図6(b)に示すように、切削ヘッド部5の嵌合部14と工具本体2の受け部20とを嵌合させた状態であって、締結ボルト30を締め付ける前の係合面16aと挟持面23aとの隙をS1、芯出し周面16bと整合面23bとの隙をS2とすると、これらの相対関係がS1<S2となるように軸部15及び凹部22が形成されている。
また、図5に示すように、各挟持面23a及び整合面23bに隣接する一対の対向領域が切屑排出溝6,6で切除され、外部に開放された一対の側部開口部22b,22bをなしている。
【0021】
そして、凹部22の底面22aには、各挟持面23a及び整合面23b間であって工具本体2の先端部分を略線対称に2分するように、つまり回転軸線O上にスリット26が形成されている。
このスリット26によって、工具本体2の先端部分は一対のハーフ部32A,32Bに分割される。ハーフ部32Aには締結ボルト30のヘッド受け部9aを有する挿通孔9がスリット26と回転軸線O付近で直交するように径方向で貫通形成されており、ハーフ部32Bには締結ボルト30を締め込むためのねじ部29が挿通孔9の延長線上に貫通形成されている。
これらハーフ部32A,32Bはスリット26の間隔を増減するように弾性変形可能とされ、切削ヘッド部5の固定時には締結ボルト30を締め込むことによって互いに接近するように弾性変形する。
【0022】
また、図6(a)に示すように、締結ボルト30を工具本体2の先端面2a側、つまりスリット26の開放側に近づけて配設するために、挿通孔9及びねじ部29の一部が凹部22内を通過するように設けられている。
このため、挿通孔9及びねじ部29に締結ボルト30を装着するとその首下部分の一部が凹部22の底面22aから突出するが、前述したように軸部15の底面15aには締結ボルト30の首下部分の逃げ部15bを設けているため、切削ヘッド5を装着した時に締結ボルト30と軸部15との干渉を防止できる。
尚、スリット26の下端側には、スリット26の長さを短くすると共に弾性変形時の応力集中を避けるためのヌスミ部26aが形成されている。また、挿通孔9及びねじ部29は、前記分岐油孔28a,28aを避ける位置に形成されている。
【0023】
また、受け部20は、先端面2aに突出成形され、切削ヘッド部5の段差部18と凹凸嵌合して工具本体2の駆動力を切削ヘッド部5に伝達して一体回転させるための受け段部24を備えている。
この受け段部24は駆動力を伝達するための径方向に延びる傾斜面24aとその周方向両側に位置し切削ヘッド部5側に比較的突出する上面部24bと上面部24bより低い位置の底面部24cとを有している。
【0024】
ここで、図5に示すように、上面部24bは底面部24cに対してドリル1の回転方向後方に位置している。また、これら一対の受け段部24は本体ランド部10b,10bの先端面2a上に一対設けられ、各々回転軸線Oの両側に180°回転対称に形成されている。尚、同図においては、図示都合上一方の受け段部24のみに符号を付す。
更に、傾斜面24a,24aは前記傾斜面18a,18aと整合可能に形成されている。具体的には、工具本体2の外周に沿う方向で、且つ、その外周側を回転方向に向けるように径方向に対して傾斜して形成されると共に、軸線方向に対する傾斜角θ2(図5における側面図に示す)が10°〜60°となるように傾斜して形成されている。
【0025】
ここで、図5において、先端面2aから距離Z(図示略)の任意高さにおける凹部22の側部開口部22bの開口幅をDとし、また、図3において、基端面5aから距離Zの真意高さにおける軸部15の係合面16a及び芯出し周面16bの幅をPとすると、これらの相対関係がD>Pとなるように設定されている。そのため、凹部22の側部開口部22bに係合面16a及び芯出し周面16bを向けて挿通させることによって、切削ヘッド部5の軸部15を工具本体2の凹部22内に挿入離脱可能となっている。
【0026】
本実施の形態によるドリル1は上述の構成を有しており、次にこのドリル1の工具本体2に切削ヘッド部5を装着する手順について説明する。
図7は、工具本体2に切削ヘッド部5を装着する際の途中段階を示す平面図、図8は装着完了状態を示す平面図である。
先ず、図7に示すように、工具本体2の受け部20における側部開口部22bに切削ヘッド部5の軸部15の係合面16a及び芯出し周面16bを向けて、図中両矢印Aに沿って凹部22内に挿入する。
切削ヘッド部5の軸部15の回転軸線Oと工具本体2の回転軸線Oとがほぼ一致した時点で、切削ヘッド部5のヘッドランド部10a,10aと工具本体2の本体ランド部10b,10bとが互いに略直交し、且つ、各一対の係合面16a及び芯出し周面16bと、挟持面23a及び整合面23bとが互いに略直交した状態となる。この時、軸部15の一対の係合面16a及び芯出し周面16bはそれぞれ凹部22の側部開口部22bに位置している。
【0027】
そして、工具本体2の受け部20に対して切削ヘッド部5を工具本体2の回転方向と逆の方向(図中矢印R’で示す)に回転させると、図8に示すように、軸部15の係合面16a及び芯出し周面16bが略90°回転して凹部22の挟持面23a及び整合面23bに内側で重なり嵌合する。同時に、切削ヘッド部5の段差部18も略90°回転して、その傾斜面18aが側面図に示すように受け部20の受け段部24の傾斜面24aに嵌合する。この状態で切削ヘッド部5のヘッドランド部10a,10aは工具本体2の本体ランド部10b,10bに精密に重なり、ドリル1として切屑排出溝6,6とランド部10,10とが工具本体2から切削ヘッド部5まで滑らかに螺旋状に連結されて一体化される。
【0028】
最後に、図9に示すように、締結ボルト30を工具本体2の挿通孔9側からねじ部29に螺合させ締め付けると、ハーフ部32A,32Bがスリット26の下端側を固定端として工具本体2側の先端面2a側、つまりスリット26の開放端側が互いに接近するように弾性変形し、スリット26の間隙を縮小させる。そして、切削ヘッド部5の軸部15を工具本体2の凹部22によって締め付けることで、工具本体2に切削ヘッド部5を堅固に固定することができる。
【0029】
この時、係合面16aと挟持面23aとが先に整合し、軸部15を下方に引き込んで切削ヘッド部5を工具本体2にしっかり密着させる。その状態で芯出し周面16bと整合面23bとが整合することで、高精度に芯出しを行いながら、工具本体2に切削ヘッド部5をより堅固に固定することができる。
また、締結ボルト30が工具本体2の先端面2a側、つまりスリット26の開放端側に近い位置で工具本体2に締め込まれるため、軸部15を強く締め付けることができ、工具本体2に切削ヘッド部5をより一層堅固に固定している。
以上の手順によってドリル1に切削ヘッド部5が装着される。
【0030】
このドリル1を用いて孔あけ加工を行う場合、図示しない工作機械のスピンドル軸を介して工具本体2に伝達された駆動力が、受け段部24から段差部18に伝達されることによって切削ヘッド部5が回転する。
この時、受け段部24及び段差部18の各傾斜面は、切削ヘッド部5又は工具本体2の外周に沿う方向で、且つ、その外周側を回転方向に向けるように径方向に対して傾斜して配置されているため、回転軸線Oを中心として回転対象に設けられる各段差部18及び受け段部24間には、駆動力によって切削ヘッド部5の径方向内側に向かう分力が発生し、切削ヘッド部5を圧縮するように作用する。
従って、上記径方向分力が切削ヘッド部5を引っ張るように作用する場合と比べて、特に工具鋼のような堅い鋼材の場合は強度的に有利となり、切削ヘッド部5の耐久性を向上させることができる。
【0031】
また、段差部18及び受け段部24の各傾斜面18a,24aは径方向だけでなく回転軸線O方向でも傾斜しているため、各傾斜面18a,24aの面積を広く形成することができ、駆動力の伝達に際して段差部18及び受け段部24に加わる面圧を低減することができる。つまり切削ヘッド部5及び工具本体2に加わる負担を低減することができ、ドリル1の耐久性を向上させることができる。
【0032】
そして、ドリル1が回転軸線O回りに一体回転し、切刃8,8によって被削材の孔加工が行われ、切刃8で生成された切屑は切屑排出溝6を通して基端側に排出される。
加工によって切刃8が摩耗したり欠損して交換が必要な場合には、上述の装着工程と逆の手順で切削ヘッド部5を取り外し、他の切削ヘッド部5を上述と同一の手順で装着すれば良い。
【0033】
上述のように本実施の形態によれば、切削ヘッド部5を工具本体2に堅固に固定することができ、ドリル1による孔あけ加工時に高い負荷が切刃8を通して切削ヘッド部5にかかっても切削ヘッド部5がずれたり外れたりすることがなく、振動を抑えて孔加工精度が精密である上に工具寿命を向上させることができる。
【0034】
また、駆動力によって切削ヘッド部5の径方向内側に向かう分力が発生し、切削ヘッド部5に対し圧縮方向に作用するため、径方向分力が切削ヘッド部5に対し引張方向に作用する場合と比べて強度的に有利となり、切削ヘッド部5の耐久性を向上させることができる。また、トルク伝達面である傾斜面18a,24aを広く形成することで切削ヘッド部5及び工具本体2に加わる負担を低減することができ、ドリル1の耐久性を向上させることができる。
【0035】
次に、上記実施の形態の応用例を図10を用いて説明する。
この応用例におけるドリル101は、軸部15の基端面5a側の芯出し周面116bが、基端面5a側に向かって広がるように形成されている以外は上記実施の形態と同一構成を有するものであり、図10において図9と同一部分に同一符号を付すと共にその設明は省略する。
この時、凹部22の整合面123bも前記芯出し周面116bに対応して、先端面2a側に向かって広がるように形成されている。
【0036】
ここで、切削ヘッド部5の嵌合部14と工具本体2の受け部20とを嵌合させた状態であって締結ボルト30を締め付ける前の芯出し周面116bと整合面123bとの隙をS3(図示略)とすると、係合面16aと挟持面23aとの隙S1との相対関係がS1<S3となるように形成されている。
【0037】
上述の構成を有するドリル101も前記実施の形態におけるドリル1と同様の手順で工具本体102に切削ヘッド部105を固定し、被削材を加工し、切削ヘッド部105を交換することができる。
また、工具本体102に切削ヘッド部105を固定するに際して、前記実施の形態と同様、締結ボルト30によって切削ヘッド部105の軸部15を工具本体102の凹部22で締め付けると、係合面16aと挟持面23aとが先に整合し、軸部15を下方に引き込んで切削ヘッド部105を工具本体102にしっかり密着させる。その状態で芯出し周面116bと整合面123bとが整合することで、高精度に芯出しを行いながら工具本体102に切削ヘッド部105を堅固に固定することができる。
【0038】
この時、軸部15の芯出し周面116bが、基端面5a側に向かって広がるように形成されているため、切削ヘッド部105の基端面5aと軸部15の軸基端の周面との角度が鈍角となり、前記実施の形態と比較して軸部15の軸基端の周囲に生ずる応力集中を軽減することができる。
【0039】
上述の応用例によれば、前記実施の形態における効果に加えて、工具本体102に切削ヘッド部105を固定した時に、軸部15の軸基端の周囲に生ずる応力集中を軽減することができるため、切削ヘッド部105に加わる負担を低減しその耐久性をより向上させることができる。
【0040】
尚、本発明は上記実施の形態に限られるものではなく、例えば切削ヘッド部5,105の周面には、係合面16a,116a及び芯出し周面16b,116bの2面が形成されているが、更に軸線と平行な周面を追加して3面としても良い。
具体的には、例えば係合面16aの軸先端面15a側にも軸線と平行な周面を別途設けて3面としても良い。また、例えば係合面16aと芯出し周面116bとの間に軸線と平行な周面を別途設けて3面としても良い。
このように、軸線と平行な周面を別途追加することで、その追加周面でも芯出しを行うことが可能となり、その精度をより高めることができる。
【0041】
【発明の効果】
以上説明したように本発明によるドリルでは、工具本体の凹部に切削ヘッド部の軸部を挿入して、嵌合部と受け部とを嵌合させた状態で締結ボルトを締め込むと、軸部の係合面によって切削ヘッド部を工具本体側に引き込んで密着させると共に、軸部の芯出し周面によって高精度に芯出しを行いながら、工具本体に切削ヘッド部を堅固に固定することが可能となるため、孔あけ加工時等に両者がずれたりすることがなく、振動を抑えて高精度な加工を行えて長寿命が得られる。
【0043】
そして、前記係合面及び芯出し周面と、前記挟持面及び整合面との隙S1及びS2の相対関係をS1<S2とすることによって、軸部を凹部で締め付けた時に、先ず係合面と挟持面とが当接し、切削ヘッド部を工具本体側に引き込んだ状態で芯出し周面と整合面とが当接して芯出しを行うことが可能となるため、高精度に芯出しを行いながら前記工具本体に前記切削ヘッド部をより堅固に固定することができる。
【0044】
また本発明において、前記工具本体には、前記締結ボルトを装着する挿通孔及びねじ部を形成し、前記挿通孔及びねじ部の一部が前記凹部内を通過するように設けるとともに、前記軸部の軸先端面に前記締結ボルトの逃げ部を形成することによって、締結ボルトの配設位置を工具本体の先端面側、つまりスリットの開放端側に近づけることが可能となるため、軸部を強く締め付けることができ、工具本体に切削ヘッド部をより一層堅固に固定することができる。
【図面の簡単な説明】
【図1】 本発明の実施の形態におけるスローアウェイ式ドリルの正面図である。
【図2】 図1の平面図である。
【図3】 本発明の実施の形態における切削ヘッド部の平面図である。
【図4】 図3の正面図である。
【図5】 本発明の実施の形態における工具本体の先端部分の平面図である。
【図6】(a)は図5の正面図、(b)は(a)における要部拡大図である。
【図7】 工具本体に切削ヘッド部を装着する際の途中段階を示す平面図である。
【図8】 工具本体に切削ヘッド部を装着した状態を示す平面図である。
【図9】 図8の正面図である。
【図10】 本発明の実施の形態の応用例を示す正面図である。
【符号の説明】
1,101 スローアウェイ式ドリル
2,102 工具本体
5,105 切削ヘッド部
14 嵌合部
15 軸部
15b 逃げ部
16a 係合面
16b,116b 芯出し周面
18 段差部
18a 傾斜面
20 受け部
22 凹部
23a 挟持面
23b,123b 整合面
24 受け段部
24a 傾斜面
26 スリット
30 締結ボルト
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a throw-away drill that can replace a cutting head portion having a cutting edge with a tool body.
[0002]
[Prior art]
Conventionally, as a throw-away type drill in which a cutting head portion having a cutting edge can be mounted on a tool body in a replaceable manner, for example, there is one described in Utility Model Registration No. 3054444.
This throw-away type drill has an elastic slit in the tool shank at the connecting part between the cutting head part and the tool shank, which is the tip end side region of the drill, and a pair of concave fixings for connection facing both sides of the elastic slit. A wall and a pair of torque transmission walls that transmit torque to the cutting head portion are formed, respectively, and the cutting head portion includes a pair of convex fixed walls that engage with the fixed wall of the tool shank, and a torque transmission wall of the tool shank. And a pair of torque conducting walls to be fitted. The minimum interval between the opposing concave fixed walls is set wider than the width of the convex fixed walls.
[0003]
And when connecting the cutting head part to the tool shank, both the fixing walls are coaxially orthogonally crossed so that the convex fixing wall of the cutting head part passes through the gap of the concave fixing wall of the tool shank, and then the cutting head part Is rotated in the direction opposite to the rotation direction of the tool body, the torque transmission wall of the cutting head portion comes into contact with the torque transmission wall of the tool shank portion, and the convex fixed wall and the concave fixed wall are coupled. The two fixed walls are connected while elastically deforming and expanding the elastic slit of the tool body, whereby the cutting head portion and the tool shank are elastically connected.
[0004]
[Problems to be solved by the invention]
However, in such a structure, the cutting head part and the tool shank part are coupled only by elastic coupling using an elastic slit. Therefore, if the coupling force between the two is small and a large cutting load is applied during drilling, the cutting is performed. There is a problem that the head portion is easily displaced or detached, the hole machining accuracy is lowered, or the tool is easily damaged, leading to an increase in machining cost.
In view of such circumstances, the present invention is a throw-away drill that can easily attach and detach the cutting head portion and can be firmly fixed, and can reduce the burden on the cutting head portion and the tool body to prevent breakage. The purpose is to provide.
[0005]
[Means for Solving the Problems]
To solve the above problem, The present invention In a throw-away type drill in which a cutting head provided with a cutting blade is detachably attached to a tool body, the cutting head part is provided with a fitting part, and the tool body is fitted with the fitting part. The fitting portion is provided with a shaft portion protruding on the axis from the base end surface of the cutting head portion to the tool body side, and provided rotationally symmetrically about the axis, and the cutting head from the base end surface. A pair of stepped portions recessed on the tip surface side of the portion, Projected from the base end face of the cutting head An engagement surface extending toward the shaft tip surface is formed on the peripheral surface of the shaft portion near the shaft tip surface, In the shaft Said Of the cutting head On the peripheral surface near the base surface It was formed so as to extend parallel to the axis or toward the base end face side of the cutting head part. A centering peripheral surface is formed, and the receiving portion is provided on the proximal end side from the distal end surface of the tool body and is fitted to the shaft portion, and protrudes from the distal end surface to the cutting head portion side. A pair of receiving stepped portions that fit into the stepped portions, The concave portion is formed with a clamping surface corresponding to the engagement surface and an alignment surface corresponding to the centering peripheral surface, The tool body is provided with a slit that divides the tip portion in the radial direction, and in a state where the fitting portion and the receiving portion are fitted, If the gap between the engagement surface and the clamping surface is S1, and the gap between the centering peripheral surface and the alignment surface is S2, then S1 <S2. By tightening a fastening bolt that penetrates the slit, the shaft portion is fastened by the concave portion to fix the cutting head portion to the tool body.
[0006]
With this configuration, when the cutting head portion is fixed to the tool body, when the fastening bolt is tightened into the tool body in a state where the fitting portion and the receiving portion are fitted, the tool body is not slitted. It is elastically deformed to reduce the gap, and the cutting head portion is drawn into close contact with the tool body side by the engaging surface of the shaft portion of the fitting portion, and centering is performed with high accuracy by the centering peripheral surface of the shaft portion. . And it becomes possible to fix | tightly fix a cutting head part to a tool main body by clamp | tightening a shaft part by a recessed part.
[0007]
In addition, The centering peripheral surface is So as to expand toward the base end face of the cutting head Formed in case of, By making the angle of the peripheral surface of the shaft base end of the shaft portion relative to the base end surface of the cutting head portion an obtuse angle, it is possible to reduce stress concentration around the shaft base end.
[0008]
And The concave portion is formed with a clamping surface corresponding to the engaging surface and an alignment surface corresponding to the centering circumferential surface, and a gap between the engaging surface and the clamping surface is defined as S1 and the centering circumferential surface. When the clearance with the alignment surface is S2, the configuration is such that S1 <S2, so that when the shaft portion is tightened with the recess, the engagement surface and the clamping surface first come into contact with each other, and the cutting head portion is placed on the tool body side. The centering peripheral surface and the alignment surface are brought into contact with each other in the state of being drawn into the center, thereby enabling centering.
[0009]
Also, In the tool body, an insertion hole and a screw part for mounting the fastening bolt are formed, and a part of the insertion hole and the screw part is provided so as to pass through the recess, By constructing the shaft bolt end surface of the shaft portion so that the relief portion of the fastening bolt is formed, the arrangement position of the fastening bolt is brought closer to the tip surface side of the tool body, that is, the open end side of the slit. It becomes possible.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a side view of a throw-away drill according to the present invention, and FIG. 2 is a plan view thereof.
As shown in FIG. 1, a throw-away type drill (hereinafter sometimes referred to as a drill) 1 according to the present embodiment has a tool body 2 having a substantially bar shape including a shank portion 3 and a blade portion 4. A throwaway type cutting head portion 5 having a pair of cutting edges 8 on a tapered tip surface 7 is replaceably attached to the tip of the portion 4.
On the outer peripheral surface 4a of the blade part 4, two chip discharge grooves 6 and 6 and land parts 10 and 10 adjacent to them are formed in a rotationally symmetrical manner around the rotation axis O of the drill body, It is twisted around the axis O.
[0013]
An oil hole 28 is formed in the tool body 2 along the rotation axis O, preferably coaxially, from the base end side (the lower side in the drawing) of the tool body 2 toward the cutting head portion 5. ing. The oil holes 28 are branched into a plurality of (two in the present embodiment) at a midway position that does not reach the cutting head portion 5, and each of the branched oil holes 28 a, 28 a extends to the outer peripheral side and is near the cutting head portion 5. The land portions 10, 10 are open to oil grooves 28b, 28b provided on the outer peripheral surface.
[0014]
As shown in FIG. 2, in the cutting head unit 5, a pair of crossed ridge lines between the tip wall surface and the tip surface 7 facing the rotation direction (indicated by an arrow R in the figure) of each chip discharge groove 6, 6 Cutting blades 8 and 8 are formed.
The concave surface portions 5b and 5b constitute a part of the oil grooves 28b and 28b, and allow direct oil supply to the cutting portion during drilling.
As shown in FIG. 1, the drill 1 having the above-described basic configuration includes a fitting portion 14 described later provided in the throw-away type cutting head portion 5 and a receiving portion 20 described later provided in the tool body 2. And the slit 26 provided so as to bisect the receiving portion 20 of the tool body 2 is elastically deformed by the fastening bolt 30 to thereby cut the cutting head portion. The cutting head portion 5 is firmly fixed to the tool body 2 by tightening the fitting portion 14.
[0015]
FIG. 3 is a plan view of the cutting head portion 5, and FIG. 4 is a side view thereof.
As shown in FIG. 3, the cutting head portion 5 is provided with a pair of head land portions 10 a and 10 a that are formed rotationally symmetrical on both sides of the rotation axis O, and is substantially concave adjacent to the head land portions 10 a and 10 a. A pair of curved concave side surfaces 6a, 6a is formed. The head land portions 10a, 10a constitute part of the land portions 10, 10, and the concave side surfaces 6a, 6a constitute part of the chip discharge grooves 6, 6.
The front end surface 7 is formed in a substantially tapered shape with the rotation axis O as the center, and is sequentially provided behind the pair of cutting blades 8 and 8 extending radially outward from the vicinity of the rotation axis O and the rotation direction of each cutting blade 8. It has a flank 11 and a thinning surface 12.
In the figure, an arrow R indicates the direction of rotation.
[0016]
As shown in FIG. 4, a fitting portion 14 for fitting with the tool main body 2 is provided on the surface (base end surface 5 a) opposite to the distal end surface 7 of the cutting head portion 5.
The fitting portion 14 includes a shaft portion 15 that is coaxial with the rotational axis O and protrudes from the base end surface 5a toward the tool body 2 and is an outer peripheral portion of the shaft portion 15 in the head land portions 10a and 10a direction. An engagement surface 16a that extends toward the shaft distal end surface 15a is formed on the peripheral surface of the shaft portion 15 near the shaft distal end surface 15a, and a rotation axis O is formed on the peripheral surface of the shaft portion 15 near the proximal end surface 5a. A centering peripheral surface 16b parallel to the center is formed.
And the escape part 15b for avoiding interference with the neck lower part of the fastening bolt 30 is recessedly provided in the axial front end surface 15a of the axial part 15. As shown in FIG.
[0017]
Moreover, the fitting part 14 is provided with the level | step-difference part 18 formed by notching the base end surface 5a to the front end surface 7 side.
The step portion 18 includes an inclined surface 18a extending in the radial direction for transmitting a driving force, and a thick portion 18b and a thin portion 18c located on both sides in the circumferential direction.
Here, as shown in FIG. 3, the thick portion 18 b is located in front of the thin portion 18 c in the rotational direction of the drill 1. A pair of step portions 18 are provided on the back surfaces of the head land portions 10a, 10a, and are formed on both sides of the rotation axis O so as to be 180 ° rotationally symmetrical. In the figure, for convenience of illustration, only one step portion 18 is provided with a reference numeral.
Further, the inclined surfaces 18a, 18a are formed in a direction along the outer periphery of the cutting head portion 5 and inclined with respect to the radial direction so that the outer peripheral side thereof is directed in the rotation direction, and an inclination angle with respect to the axial direction. Inclined so that θ1 (shown in the side view in FIG. 3) is 10 ° to 60 °.
[0018]
FIG. 5 is a plan view of the tip portion of the tool body 2, FIG. 6A is a side view thereof, and FIG. 6B is an enlarged view of a main part in FIG.
As shown in FIG. 5, the blade portion 4 of the tool body 2 is provided with a pair of main body land portions 10 b and 10 b formed symmetrically on both sides of the rotation axis O adjacent to the chip discharge grooves 6 and 6. The main body land portions 10b and 10b constitute the land portions 10 and 10 together with the head land portions 10a and 10a. In the figure, an arrow R indicates the direction of rotation.
[0019]
As shown in FIG. 6A, a receiving portion 20 for fitting the cutting head portion 5 is provided on the distal end surface 2 a of the tool main body 2.
The receiving portion 20 includes a concave portion 22 in which the distal end surface 2a of the tool main body 2 is cut out toward the base end side (the lower side in the drawing) of the tool main body 2, and the main body land portion 10b of the concave portion 22 is provided. , 10b direction, a peripheral surface near the bottom surface 22a of the recess 22 is formed with a clamping surface 23a corresponding to the engagement surface 16a, and the peripheral surface near the tip surface 2a of the recess 22 An alignment surface 23b corresponding to the centering peripheral surface 16b is formed.
[0020]
Here, as shown in FIG. 6B, the engagement before the fastening bolt 30 is tightened in a state where the fitting portion 14 of the cutting head portion 5 and the receiving portion 20 of the tool body 2 are fitted. If the clearance between the surface 16a and the clamping surface 23a is S1, and the clearance between the centering peripheral surface 16b and the alignment surface 23b is S2, the shaft portion 15 and the recess 22 are formed so that the relative relationship between them is S1 <S2. ing.
Further, as shown in FIG. 5, a pair of opposing regions adjacent to each clamping surface 23a and alignment surface 23b are cut off by chip discharge grooves 6 and 6, and a pair of side openings 22b and 22b opened to the outside are provided. There is no.
[0021]
A slit 26 is formed on the bottom surface 22a of the recess 22 so as to bisect the tip end portion of the tool body 2 between the respective clamping surfaces 23a and the alignment surface 23b in a substantially line symmetrical manner, that is, on the rotation axis O. ing.
The slit 26 divides the tip portion of the tool body 2 into a pair of half portions 32A and 32B. An insertion hole 9 having a head receiving portion 9a for the fastening bolt 30 is formed through the half portion 32A in a radial direction so as to be perpendicular to the slit 26 and the rotation axis O, and the fastening bolt 30 is tightened to the half portion 32B. A screw portion 29 for insertion is formed through the extension line of the insertion hole 9.
These half portions 32A and 32B can be elastically deformed so as to increase or decrease the interval of the slit 26, and when the cutting head portion 5 is fixed, the half bolts 32A and 32B are elastically deformed so as to approach each other by tightening the fastening bolt 30.
[0022]
Further, as shown in FIG. 6A, in order to dispose the fastening bolt 30 close to the tip end surface 2 a side of the tool body 2, that is, the open side of the slit 26, a part of the insertion hole 9 and the screw portion 29. Is provided so as to pass through the recess 22.
For this reason, when the fastening bolt 30 is attached to the insertion hole 9 and the screw portion 29, a part of the lower neck portion protrudes from the bottom surface 22a of the concave portion 22, but as described above, the fastening bolt 30 is formed on the bottom surface 15a of the shaft portion 15. Therefore, when the cutting head 5 is mounted, interference between the fastening bolt 30 and the shaft portion 15 can be prevented.
A slit 26a is formed on the lower end side of the slit 26 to shorten the length of the slit 26 and to avoid stress concentration during elastic deformation. Further, the insertion hole 9 and the screw portion 29 are formed at positions avoiding the branched oil holes 28a, 28a.
[0023]
Further, the receiving portion 20 is formed to protrude from the tip surface 2a, and is fitted to the stepped portion 18 of the cutting head portion 5 so that the driving force of the tool body 2 is transmitted to the cutting head portion 5 to rotate integrally. A step 24 is provided.
The receiving step portion 24 includes an inclined surface 24a extending in the radial direction for transmitting a driving force, an upper surface portion 24b that is located on both sides in the circumferential direction and relatively protrudes toward the cutting head portion 5, and a bottom surface that is lower than the upper surface portion 24b. Part 24c.
[0024]
Here, as shown in FIG. 5, the upper surface portion 24 b is located behind the bottom surface portion 24 c in the rotation direction of the drill 1. A pair of these receiving step portions 24 is provided on the front end surface 2a of the main body land portions 10b, 10b, and is formed on both sides of the rotation axis O by 180 ° rotational symmetry. In the figure, for convenience of illustration, only one receiving step 24 is given a reference numeral.
Further, the inclined surfaces 24a, 24a are formed so as to be aligned with the inclined surfaces 18a, 18a. Specifically, it is formed in a direction along the outer periphery of the tool body 2 and inclined with respect to the radial direction so that the outer peripheral side is directed in the rotation direction, and an inclination angle θ2 with respect to the axial direction (in FIG. 5). (Shown in the side view) is inclined so as to be 10 ° to 60 °.
[0025]
Here, in FIG. 5, the opening width of the side opening 22b of the recess 22 at an arbitrary height Z (not shown) from the distal end surface 2a is D, and in FIG. When the width of the engaging surface 16a and the centering peripheral surface 16b of the shaft portion 15 at the true height is P, the relative relationship between them is set to satisfy D> P. Therefore, by inserting the engagement surface 16a and the centering peripheral surface 16b into the side opening 22b of the recess 22, the shaft portion 15 of the cutting head portion 5 can be inserted into and removed from the recess 22 of the tool body 2. It has become.
[0026]
The drill 1 according to the present embodiment has the above-described configuration. Next, a procedure for mounting the cutting head portion 5 on the tool body 2 of the drill 1 will be described.
FIG. 7 is a plan view showing an intermediate stage when the cutting head portion 5 is mounted on the tool body 2, and FIG. 8 is a plan view showing a mounting completion state.
First, as shown in FIG. 7, the engagement surface 16 a and the centering peripheral surface 16 b of the shaft portion 15 of the cutting head portion 5 are directed to the side opening 22 b in the receiving portion 20 of the tool body 2, and double arrows in the drawing. Insert it into the recess 22 along A.
When the rotation axis O of the shaft portion 15 of the cutting head portion 5 and the rotation axis O of the tool body 2 substantially coincide with each other, the head land portions 10a and 10a of the cutting head portion 5 and the body land portions 10b and 10b of the tool body 2 are obtained. Are substantially orthogonal to each other, and the pair of engaging surfaces 16a and the centering peripheral surface 16b, and the sandwiching surface 23a and the alignment surface 23b are substantially orthogonal to each other. At this time, the pair of engaging surfaces 16 a and the centering peripheral surface 16 b of the shaft portion 15 are respectively located in the side opening 22 b of the recess 22.
[0027]
Then, when the cutting head portion 5 is rotated with respect to the receiving portion 20 of the tool body 2 in the direction opposite to the rotation direction of the tool body 2 (indicated by an arrow R ′ in the figure), as shown in FIG. The 15 engaging surfaces 16a and the centering peripheral surface 16b are rotated by approximately 90 °, and overlapped and engaged with the sandwiching surface 23a and the alignment surface 23b of the recess 22 on the inside. At the same time, the step portion 18 of the cutting head portion 5 is also rotated by approximately 90 °, and the inclined surface 18a is fitted to the inclined surface 24a of the receiving step portion 24 of the receiving portion 20 as shown in the side view. In this state, the head land portions 10a, 10a of the cutting head portion 5 are precisely overlapped with the main body land portions 10b, 10b of the tool body 2, and the chip discharge grooves 6, 6 and the land portions 10, 10 serve as the drill 1 as the tool body 2. To the cutting head portion 5 are smoothly connected and integrated in a spiral manner.
[0028]
Finally, as shown in FIG. 9, when the fastening bolt 30 is screwed into the threaded portion 29 from the insertion hole 9 side of the tool main body 2 and tightened, the half portions 32A and 32B have the lower end side of the slit 26 as a fixed end. The two end surfaces 2a, that is, the open ends of the slits 26 are elastically deformed so as to approach each other, and the gap of the slits 26 is reduced. Then, the cutting head portion 5 can be firmly fixed to the tool body 2 by tightening the shaft portion 15 of the cutting head portion 5 with the recess 22 of the tool body 2.
[0029]
At this time, the engaging surface 16a and the clamping surface 23a are aligned first, and the shaft portion 15 is pulled downward to firmly attach the cutting head portion 5 to the tool body 2. By aligning the centering peripheral surface 16b and the alignment surface 23b in this state, the cutting head unit 5 can be more firmly fixed to the tool body 2 while performing centering with high accuracy.
Further, since the fastening bolt 30 is fastened to the tool main body 2 at a position close to the tip end surface 2a side of the tool main body 2, that is, the open end side of the slit 26, the shaft portion 15 can be strongly tightened and the tool main body 2 is cut. The head portion 5 is fixed more firmly.
The cutting head 5 is mounted on the drill 1 by the above procedure.
[0030]
When drilling is performed using this drill 1, the driving force transmitted to the tool body 2 via a spindle shaft of a machine tool (not shown) is transmitted from the receiving step portion 24 to the step portion 18, thereby cutting head. Part 5 rotates.
At this time, each inclined surface of the receiving step portion 24 and the step portion 18 is inclined in the direction along the outer periphery of the cutting head portion 5 or the tool main body 2 and in the radial direction so that the outer peripheral side is directed in the rotation direction. Therefore, a component force directed inward in the radial direction of the cutting head portion 5 is generated between each stepped portion 18 and the receiving stepped portion 24 provided on the rotation target around the rotation axis O by a driving force. It acts to compress the cutting head part 5.
Therefore, compared to the case where the radial component force acts to pull the cutting head portion 5, particularly in the case of a hard steel material such as tool steel, the strength is advantageous, and the durability of the cutting head portion 5 is improved. be able to.
[0031]
Further, since the inclined surfaces 18a and 24a of the stepped portion 18 and the receiving step portion 24 are inclined not only in the radial direction but also in the rotation axis O direction, the areas of the inclined surfaces 18a and 24a can be formed wide. The surface pressure applied to the stepped portion 18 and the receiving stepped portion 24 during transmission of the driving force can be reduced. That is, the load applied to the cutting head unit 5 and the tool body 2 can be reduced, and the durability of the drill 1 can be improved.
[0032]
Then, the drill 1 rotates integrally around the rotation axis O, the workpiece 8 is drilled by the cutting blades 8, 8, and the chips generated by the cutting blade 8 are discharged to the base end side through the chip discharge groove 6. The
If the cutting edge 8 is worn or lost due to processing and needs to be replaced, the cutting head 5 is removed in the reverse procedure of the above mounting process, and the other cutting head 5 is mounted in the same procedure as described above. Just do it.
[0033]
As described above, according to the present embodiment, the cutting head unit 5 can be firmly fixed to the tool body 2, and a high load is applied to the cutting head unit 5 through the cutting blade 8 during drilling with the drill 1. However, the cutting head portion 5 is not displaced or detached, so that the vibration can be suppressed and the hole machining accuracy is precise and the tool life can be improved.
[0034]
In addition, a component force directed inward in the radial direction of the cutting head portion 5 is generated by the driving force, and acts on the cutting head portion 5 in the compression direction. Therefore, the radial component force acts on the cutting head portion 5 in the tensile direction. Compared to the case, it is advantageous in terms of strength, and the durability of the cutting head portion 5 can be improved. Moreover, the burden added to the cutting head part 5 and the tool main body 2 can be reduced by forming the inclined surfaces 18a and 24a which are torque transmission surfaces widely, and the durability of the drill 1 can be improved.
[0035]
Next, an application example of the above embodiment will be described with reference to FIG.
The drill 101 in this application example has the same configuration as that of the above-described embodiment except that the centering peripheral surface 116b on the base end surface 5a side of the shaft portion 15 is formed so as to expand toward the base end surface 5a side. In FIG. 10, the same parts as those in FIG. 9 are denoted by the same reference numerals and their description is omitted.
At this time, the alignment surface 123b of the concave portion 22 is also formed so as to expand toward the front end surface 2a side corresponding to the centering peripheral surface 116b.
[0036]
Here, there is a gap between the centering peripheral surface 116b and the alignment surface 123b before the fastening bolt 30 is tightened in a state where the fitting portion 14 of the cutting head portion 5 and the receiving portion 20 of the tool body 2 are fitted. Assuming that S3 (not shown), the relative relationship between the gap S1 between the engagement surface 16a and the clamping surface 23a is S1 <S3.
[0037]
The drill 101 having the above-described configuration can also replace the cutting head portion 105 by fixing the cutting head portion 105 to the tool body 102, processing the work material, in the same procedure as the drill 1 in the above embodiment.
Further, when the cutting head portion 105 is fixed to the tool main body 102, when the shaft portion 15 of the cutting head portion 105 is fastened to the concave portion 22 of the tool main body 102 by the fastening bolt 30, the engagement surface 16a is fixed. The clamping surface 23 a is aligned first, and the shaft portion 15 is pulled downward to firmly attach the cutting head portion 105 to the tool body 102. By aligning the centering peripheral surface 116b and the alignment surface 123b in this state, the cutting head unit 105 can be firmly fixed to the tool body 102 while performing centering with high accuracy.
[0038]
At this time, since the centering peripheral surface 116b of the shaft portion 15 is formed so as to expand toward the base end surface 5a side, the base end surface 5a of the cutting head portion 105 and the peripheral surface of the shaft base end of the shaft portion 15 This becomes an obtuse angle, and stress concentration generated around the shaft base end of the shaft portion 15 can be reduced as compared with the above-described embodiment.
[0039]
According to the application example described above, in addition to the effects in the embodiment, when the cutting head portion 105 is fixed to the tool body 102, stress concentration generated around the shaft base end of the shaft portion 15 can be reduced. Therefore, the load applied to the cutting head unit 105 can be reduced and the durability thereof can be further improved.
[0040]
The present invention is not limited to the above-described embodiment. For example, two surfaces of the peripheral surfaces of the cutting head portions 5 and 105, that is, engagement surfaces 16a and 116a and centering peripheral surfaces 16b and 116b are formed. However, a peripheral surface parallel to the axis may be added to obtain three surfaces.
Specifically, for example, a peripheral surface parallel to the axis may be separately provided on the side of the shaft tip surface 15a of the engagement surface 16a to form three surfaces. Further, for example, a peripheral surface parallel to the axis line may be separately provided between the engagement surface 16a and the centering peripheral surface 116b to form three surfaces.
Thus, by separately adding a peripheral surface parallel to the axis, centering can be performed even on the additional peripheral surface, and the accuracy can be further increased.
[0041]
【The invention's effect】
As described above, in the drill according to the present invention, the shaft portion of the cutting head portion is inserted into the recess of the tool body. And When the fastening bolt is tightened in a state where the fitting portion and the receiving portion are fitted, the cutting head portion is drawn into close contact with the tool body side by the engagement surface of the shaft portion, and the centering peripheral surface of the shaft portion Since the cutting head can be firmly fixed to the tool body while performing high-precision centering, both do not shift during drilling, etc. Can be used for long life.
[0043]
And When the relative relationship of the gaps S1 and S2 between the engagement surface and the centering peripheral surface, and the clamping surface and the alignment surface is set to S1 <S2, when the shaft portion is tightened by the concave portion, the engagement surface and the alignment surface are first clamped. Since the centering peripheral surface and the alignment surface come into contact with each other and the centering surface is brought into contact with the alignment surface in a state where the cutting head portion is pulled to the tool body side, the above-mentioned is performed while performing centering with high accuracy. The cutting head portion can be more firmly fixed to the tool body.
[0044]
In the present invention, In the tool body, an insertion hole and a screw part for mounting the fastening bolt are formed, and a part of the insertion hole and the screw part is provided so as to pass through the recess, By forming a relief portion of the fastening bolt on the shaft tip surface of the shaft portion, it becomes possible to bring the fastening bolt arrangement position closer to the tip surface side of the tool body, that is, the open end side of the slit. The part can be tightened strongly, and the cutting head part can be more firmly fixed to the tool body.
[Brief description of the drawings]
FIG. 1 is a front view of a throw-away drill according to an embodiment of the present invention.
FIG. 2 is a plan view of FIG.
FIG. 3 is a plan view of a cutting head portion according to the embodiment of the present invention.
4 is a front view of FIG. 3. FIG.
FIG. 5 is a plan view of the tip portion of the tool body in the embodiment of the present invention.
6A is a front view of FIG. 5, and FIG. 6B is an enlarged view of a main part in FIG.
FIG. 7 is a plan view showing an intermediate stage when the cutting head is mounted on the tool body.
FIG. 8 is a plan view showing a state in which a cutting head is mounted on the tool body.
FIG. 9 is a front view of FIG. 8;
FIG. 10 is a front view showing an application example of the embodiment of the present invention.
[Explanation of symbols]
1,101 Throwaway drill
2,102 Tool body
5,105 Cutting head
14 Fitting part
15 Shaft
15b Escape part
16a engagement surface
16b, 116b Centering circumference
18 steps
18a Inclined surface
20 Receiver
22 recess
23a clamping surface
23b, 123b Alignment surface
24 receiving step
24a inclined surface
26 Slit
30 Fastening bolt

Claims (2)

切刃が設けられた切削ヘッド部を工具本体に着脱可能に装着してなるスローアウェイ式ドリルにおいて、
前記切削ヘッド部には嵌合部が設けられ、前記工具本体には前記嵌合部と嵌合可能な受け部が設けられ、
前記嵌合部は、切削ヘッド部の基端面から工具本体側に軸線上で突出する軸部と、軸線を中心として回転対称に設けられ前記基端面から切削ヘッド部の先端面側に凹設される一対の段差部とを備え、
前記切削ヘッド部の基端面から突出した前記軸部の軸先端面寄りの周面には軸先端面に向かって広がる係合面が形成され、該軸部における前記切削ヘッド部の基端面寄りの周面には前記軸線に平行または前記切削ヘッド部の基端面側に向かって拡がるように形成された芯出し周面が形成され、
前記受け部は、工具本体の先端面からその基端側に設けられ前記軸部に嵌合する凹部と、前記先端面から切削ヘッド部側に凸設され前記各段差部に嵌合する一対の受け段部とを備え、
前記凹部には、前記係合面に対応する挟持面と、前記芯出し周面に対応する整合面とが形成され、
前記工具本体には、その先端部分を径方向で分割するスリットが設けられ、前記嵌合部と前記受け部とを嵌合させた状態で、前記係合面と挟持面との隙をS1、前記芯出し周面と整合面との隙をS2とすると、S1<S2とされ、前記スリットを貫通する締結ボルトを締め込むことによって、前記軸部を前記凹部で締め付けて前記工具本体に前記切削ヘッド部を固定することを特徴とするスローアウェイ式ドリル。
In the throw-away drill, in which the cutting head provided with the cutting blade is detachably attached to the tool body,
The cutting head portion is provided with a fitting portion, and the tool body is provided with a receiving portion that can be fitted with the fitting portion,
The fitting portion is provided so as to be rotationally symmetrical about the axis from the base end surface of the cutting head portion to the tool main body side on the axis side, and is recessed from the base end surface to the distal end surface side of the cutting head portion. A pair of stepped portions,
The cutting on the peripheral surface of the head portion axially distal end surface side of the said shaft portion protruding from the proximal end surface of the engagement surface extending toward the shaft tip surface is formed, the cutting head portion in the shaft portion of the proximal end surface nearer A centering peripheral surface is formed on the peripheral surface so as to extend parallel to the axis or toward the base end surface side of the cutting head portion ,
The receiving portion is provided on the proximal end side from the distal end surface of the tool body and is fitted to the shaft portion, and a pair of projections projecting from the distal end surface to the cutting head portion side and fitted to the step portions. With a receiving step,
The concave portion is formed with a clamping surface corresponding to the engagement surface and an alignment surface corresponding to the centering peripheral surface,
The tool body is provided with a slit that divides the tip portion in the radial direction, and in a state where the fitting portion and the receiving portion are fitted , a gap between the engagement surface and the clamping surface is S1, Assuming that the gap between the centering peripheral surface and the alignment surface is S2, S1 <S2, and by tightening a fastening bolt that passes through the slit, the shaft portion is fastened by the concave portion to the tool body. A throw-away drill characterized by fixing the head.
前記工具本体には、前記締結ボルトを装着する挿通孔及びねじ部が形成され、前記挿通孔及びねじ部の一部が前記凹部内を通過するように設けられるとともに、前記軸部の軸先端面には、前記締結ボルトの逃げ部が形成されていることを特徴とする請求項1に記載のスローアウェイ式ドリル。 The tool body is formed with an insertion hole and a screw part for mounting the fastening bolt, and the insertion hole and a part of the screw part are provided so as to pass through the recess, and the shaft tip surface of the shaft part The throwaway drill according to claim 1, wherein a relief portion of the fastening bolt is formed.
JP2002096740A 2002-03-29 2002-03-29 Throw-away drill Expired - Fee Related JP3812480B2 (en)

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SE528020C2 (en) * 2004-01-14 2006-08-08 Sandvik Intellectual Property Rotatable chip separating tool
IL162147A (en) * 2004-05-24 2008-03-20 Gil Hecht Drill with releasably mounted cutting head
IL164888A (en) 2004-10-28 2009-07-20 Iscar Ltd Cutting tool assembly and cutting head therefor
CN102015171A (en) * 2008-04-25 2011-04-13 钴领无限公司 Rotary-driven tool for cutting machining with a cutting body
JP5051801B2 (en) * 2011-03-03 2012-10-17 株式会社ビック・ツール drill
US10799958B2 (en) * 2017-08-21 2020-10-13 Kennametal Inc. Modular rotary cutting tool
CN112077370B (en) 2019-06-13 2024-10-01 肯纳金属印度有限公司 Indexable drill insert

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