JP2004050370A

JP2004050370A - Drilling tool

Info

Publication number: JP2004050370A
Application number: JP2002213750A
Authority: JP
Inventors: Kimishige Odawara; 小田原　公茂; Yukimasa Fukumoto; 福本　幸正
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2002-07-23
Filing date: 2002-07-23
Publication date: 2004-02-19
Anticipated expiration: 2022-07-23
Also published as: JP3897105B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drilling tool which removes burrs produced in the course of drilling, while continuously carrying out the drilling. <P>SOLUTION: The drilling tool is comprised of: a first cutting edge 15; a recessed clearance portion 16; a second cutting edge 18; and a third cutting edge 20. The edge 15 is tilted at a predetermined tilt angle with respect to a rotation shaft so as to approach the same at a location closer to a distal end thereof. The portion 16 is formed at the edge of the distal end of the first cutting edge. The edge 18 extends from the clearance portion in a manner being in parallel with the rotation shaft or tilted with respect to the same so as to approach the shaft at a location closer to a distal end thereof. A tilt angle of the second cutting edge with respect to the rotation shaft is smaller than that of the first cutting edge. The edge 20 is the same in tilt angle with respect to the rotation shaft as the second cutting edge, and formed on the rear of the clearance portion in a relative rotating direction. A cutting edge region determined by projecting the third cutting edge orthogonally to the rotation shaft includes a clearance portion region determined by protecting the release portion orthogonally to the rotation shaft. Thus, the burrs of a workpiece produced by the clearance portion are cut by the third cutting edge. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、穴明け工具に関する。
【０００２】
【従来の技術】
切削工具としての穴明け工具は、被削材の加工穴の内周形状を工具の外周形状と同一形状に加工することを目的に用いられる。穴明け工具には様々な形状のものがあり、面取り加工、内径加工、底面加工などといった用途に応じた形状のものが使い分けられている。
【０００３】
図５（Ａ）は従来の穴明け工具の一つである穴明けボーリングバイト３０の一例を示す図である。図示する例の穴明けボーリングバイト３０は被削材３１の加工穴の開口縁部の面取り加工、及び加工穴の内周壁を切削する内径加工を行う他、底壁に更に小径の加工穴３３が存在する加工穴について、小径の加工穴３３の開口縁部の面取りも併せて行うためのものである。開口縁部の面取りと内周壁の切削とを行う穴明けボーリングバイト３０の場合、面取り加工を行う第一切り刃１と内周壁を切削する第二切り刃２との交点部ＰにＲ形状が残り、それにより被削材においても第一切り刃１が形成した面と第二切り刃２が形成した面との稜線部にＲ形状が残るという問題がある。このため従来のボーリングバイト３０では、被削材の稜線部にＲ形状を生じさせないよう第一切り刃１と第二切り刃２との交点部Ｐに逃がし部３が設けられている。逃がし部３を設けることにより交点部ＰのＲ形状が取り除かれ、これにより被削材の稜線部にＲ形状が生じることを防止している。
【０００４】
【発明が解決しようとする課題】
しかしながら、逃がし部を設けると逃がし部に入り込んだ被削材の一部がばりとなって残るという問題がある。
【０００５】
図５（Ｂ）は穴明けボーリングバイト３０の一部を拡大して示す図である。図示するように逃がし部３は第一切り刃１と第二切り刃２との間に設けられることから、逃がし部３に入り込んだ被削材の一部はどちらの切り刃によっても切削されることがなく、最終的にばり４となって残る。
【０００６】
ばりに起因して生じる問題は多く、場合によっては多額の損失を招く可能性がある。そのため加工時におけるばりの除去やばりの抑制に対する要求は強く、従来は除去のための専用化された高額設備を導入したり、ブラシ類を用いて除去作業を行ったり、検査器を使ってばりの有無の確認を行ったりするなど、ばりの除去や検査に多くの費用を費やしている。
【０００７】
本発明は上述の問題に鑑みて創作されたものであって、穴明け加工の過程で生じるばりを穴明け加工をしつつ除去できる穴明け工具を提供することを目的とする。
【０００８】
【課題を解決するための手段】
請求項１に記載の穴明け工具は、第一切り刃と第二切り刃との境界に凹み状の逃がし部が設けられている。これにより第一切り刃と第二切り刃との間に生じるＲ形状を取り除いている。しかしながら、逃がし部を設けたことで被削材の第一切り刃によって形成された面と第二切り刃によって形成された面との稜線部にばりが生じることになる。請求項１に記載の穴明け工具の逃がし部の相対回転方向後方には、回転軸に対する傾斜角度が第二切り刃の傾斜角度と等しい第三切り刃が形成されており、第三切り刃を回転軸へ垂直に投影した切り刃領域は、逃がし部を回転軸へ垂直に投影した逃がし部領域を含んでいる。従って、穴明け工具の先端部が加工穴に当接して穴明け工具の送り方向への送りが停止した状態で穴明け工具が回転軸周りに回転すると、逃がし部によって生じたばりは第三切り刃によって切削される。よって請求項１に記載の穴明け工具によると、穴明け加工の過程で被削材に生じるばりを穴明け加工をしつつ除去できる。
【０００９】
請求項２に記載の穴明け工具は、逃がし部領域の後端部側の端部から切り刃領域の後端部側の端部までの長さが、回転軸に直交する面上において回転軸を中心に逃がし部と当該第三切り刃とで形成される角度を相対回転する間に穴明け工具が送り方向に相対移動する距離分の長さ以上である。よって請求項２に記載の穴明け工具によると、穴明け工具が送り方向へ送られつつ相対回転している間も第三切り刃によってばりを切削できる。
【００１０】
請求項３に記載の穴明け工具によると、被削材の第一切り刃によって形成された面、第二切り刃によって形成された面及び第三切り刃によって形成された面と穴明け工具との不要な接触を避けることができる。
【００１１】
請求項４に記載の穴明け工具によると、第一切り刃、第二切り刃及び第三切り刃によって生じた切り屑を排出できる。
請求項５に記載の穴明け工具によると、第一切り刃、第二切り刃及び第三切り刃によって生じた切り屑をよりスムーズに排出できる。
【００１２】
請求項６に記載の穴明け工具によると、生じたばりが溝に沿って相対的に進行することで穴明け工具はばりに接触することなく相対回転できる。従ってばりに接触しないようにするために第一逃げ面及び第二逃げ面を大きく逃がす必要がなく、第一切り刃及び第二切り刃の強度を保つことができる。
【００１３】
請求項７に記載の穴明け工具によると、第一切り刃のみでなく第三切り刃によっても加工穴の内周壁を切削できる。
【００１４】
【発明の実施の形態】
以下、本発明の実施例を図面にもとづいて説明する。
図２は、本発明の一実施例である穴明け工具を示す図である。本実施例の穴明け工具は、被削材に予め開口した加工穴に対する穴明け加工を行う穴明けボーリングバイト１０である。加工穴はその内径の半径が穴明けボーリングバイト１０の回転軸２６から後述する第二切り刃１８までの半径より小径である。穴明けボーリングバイト１０は所定の送り量で被削材に対して相対回転することにより加工穴の開口縁部を切削して面取りを行うとともに、加工穴内周壁の切削を行って内周壁の内径を拡大し、それにより加工穴の内周形状を穴明けボーリングバイト１０の外周形状と同一形状に加工する。ここで送り量とは１回転当たりの送り方向への相対移動量のことをいい、例えば１回転する間に送り方向にＶｍｍ移動した場合、送り量はＶｍｍとなる。尚、本実施例では加工穴の内部に段差があって加工穴の内径が途中で小さくなっている加工穴、すなわち加工穴の底壁に更に小径の加工穴が存在する加工穴について、小径の加工穴の開口縁部の面取りも併せて行う穴明けボーリングバイト１０を例に説明する。このため本実施例の穴明けボーリングバイト１０の先端部には小径の加工穴の面取りを行うための一対の切り刃が設けられている。
【００１５】
図１（Ａ）は穴明けボーリングバイト１０を拡大して示す図であり、図１（Ｂ）は図１（Ａ）に示す穴明けボーリングバイト１０を逆方向から見た図である。穴明けボーリングバイト１０は超硬合金からなり、シャンク部１１、第一切り屑排出溝１２、第二切り屑排出溝１３、第一逃げ面１４、第一切り刃１５、逃がし部、第二逃げ面１７、第二切り刃１８、第三逃げ面１９、第三切り刃２０、先端部としての底部２１、一対の第四切り刃２２及び一対の切り屑排出溝２３を備える。
【００１６】
シャンク部１１は円柱形状であり、使用に際してシャンク部１１が例えば工作機械に保持されて回転させられる。これによりシャンク部１１は回転軸２６周りに回転する。ここで方向２７は穴明けボーリングバイト１０の被削材に対する相対回転方向を示している。
【００１７】
穴明けボーリングバイト１０の底部２１からは、第一切り刃１５及び第二切り刃１８の切り屑を排出する第一切り屑排出溝１２、並びに第三切り刃２０による切屑を排出する第二切り屑排出溝１３が形成されている。第一切り屑排出溝１２は穴明けボーリングバイト１０の底部２１から、第二切り刃１８と第三逃げ面１９との間、逃がし部としての凹み部１６ａ及び溝部１６ｂと第三逃げ面１９との間、更に第一切り刃１５と第三逃げ面１９との間を穴明けボーリングバイト１０の後端部へ向かって相対回転方向２７の逆方向へ螺旋状にねじれて延びている。同様に第二切り屑排出溝１３は、第二逃げ面１７と第三切り刃２０との間、更に第一逃げ面１４と第三切り刃２０との間を後端部へ向かって相対回転方向２７の逆方向へ螺旋状にねじれて延びている。第一切り屑排出溝１２と第二切り屑排出溝１３とは同方向にねじれているため、互いに交差することはない。尚、第一切り屑排出溝１２及び第二切り屑排出溝１３はねじれずに後端部に延びていてもよい。
【００１８】
第一逃げ面１４はシャンク部１１に連なっており、概ね円錐曲面状に後端部に向かってねじれて延びている。第一逃げ面１４と第一切り屑排出溝１２の壁面とは稜線部を形成しており、その稜線部に第一切り刃１５が形成されている。すなわち、第一逃げ面１４は、第一切り刃１５の相対回転方向２７後方に連なっている。
【００１９】
第一切り刃１５の端部Ｅは図示するようにシャンク部１１に連なっている。従って第一切り刃１５はシャンク部１１より先端部側に形成されている。第一切り刃１５はシャンク部１１に連なる端部Ｅから底部２１側の他端部Ｆへいくにつれて回転軸２６に近づくよう回転軸２６に対して所定の傾斜角度で傾斜しており、所定の切刃角をもって形成されている。第一切り刃１５は被削材の加工穴の開口縁部を切削するためのものであり、穴明けボーリングバイト１０と被削材とを相対回転させることで第一切り刃１５が被削材の開口縁部を切削し、これにより面取りが行われて被削材の開口縁部に面が形成される。
【００２０】
逃がし部は、第一切り刃１５の先端部側の端部に凹み状に設けられている凹み部１６ａと、凹み部１６ａから第一逃げ面１４と第二逃げ面１７との間を後端部に向かって溝状にねじれて延びる溝部１６ｂとを備える。図４（Ａ）は逃がし部を示す拡大図である。図示するように第一切り刃１５と第二切り刃１８との境界、すなわち交点部ＱにはＲ形状ではなく凹み部１６ａが設けられている。凹み部１６ａを設けることにより第一切り刃１５と第二切り刃１８との間にＲ形状がなくなり、これにより第一切り刃１５によって形成される被削材の面と第二切り刃１８によって形成される被削材の面との稜線部にＲ形状が生じることを防止している。しかしながら、凹み部１６ａは第一切り刃１５と第二切り刃１８との間に設けられることから、凹み部１６ａに入り込んだ被削材の一部はどちらの切り刃によっても切削されることがなく、従って凹み部１６ａに入り込んだ被削材の一部はばり２４となって残ることになる。これにより逃がし部によってばり２４が生じる。生じたばり２４は穴明けボーリングバイト１０が回転しつつ送られるとき、溝部１６ｂに沿って相対的に進むことで穴明けボーリングバイト１０に接触することなく第三切り刃２０まで到達する。溝部１６ｂの形状は、底部２１が加工穴の底壁に当接して穴明けボーリングバイト１０の送り方向Ｙへの送りが停止したとき、残されたばりが回転軸２６に垂直な方向に穴明けボーリングバイト１０に接触することなく第三切り刃２０まで到達する形状に形成されている。なお、第一逃げ面１４及び第二逃げ面１７が大きく逃げており、溝部１６ｂを設けなくてもばり２４が穴明けボーリングバイト１０に接触しなければ溝部１６ｂを設けなくてもよい。
【００２１】
図１（Ａ）及び図１（Ｂ）に示すように、第二逃げ面１７は底部２１に連なっており、概ね円柱曲面状である。第二逃げ面１７と第一切り屑排出溝１２の壁面とは稜線部を形成しており、その稜線部に第二切り刃１８が形成されている。すなわち、第二逃げ面１７は、第二切り刃１８の相対回転方向２７後方に連なっている。
【００２２】
第二切り刃１８は、一方の端部が底部２１に連なり、他方の端部が逃がし部の凹み部１６ａに連なり、回転軸２６に概ね平行で段差がない形状である。ここでいう回転軸２６に概ね平行とは、切削をスムーズに行うために所定の角度だけ回転軸２６に対して相対回転方向２７に傾斜していることをいう。第二切り刃１８は概ね回転軸２６に平行であるため、第二切り刃１８の回転軸２６に対する傾斜角度は概ね０度ということになる。本実施例の第一切り刃１５の回転軸２６に対する傾斜角度は図１（Ａ）に示すように概ね４５度であるため、第二切り刃１８の回転軸２６に対する傾斜角度は第一切り刃１５の回転軸２６に対する傾斜角度より小さくなっている。第二切り刃１８は加工時に被削材に空いた加工穴の内周壁を切削し、加工穴の内径を拡大する。
【００２３】
尚、本実施例の第二切り刃１８は概ね回転軸２６に平行であるが、第二切り刃１８は底部２１側にいくにつれて回転軸２６に近づくよう回転軸２６に対して傾斜してもよい。この場合、第二切り刃１８の回転軸２６に対する傾斜角度は、第一切り刃の回転軸２６に対する傾斜角度より小さければ任意の角度であってよく、その傾斜角度は加工穴の形状に応じて適宜変更してよい。また、第二切り刃１８は底部２１側にいくにつれて回転軸２６に近づくよう回転軸２６に対して傾斜しつつ、切削をスムーズに行うために回転軸２６に対して相対回転方向２７に傾斜していてもよい。
【００２４】
先端部としての底部２１は、加工穴の底壁に当接する面と、その面に連なり円錐曲面状に後端部に向かってねじれて延びる面とを有している。底部２１が加工穴の底壁に当接することで穴明けボーリングバイト１０の送り方向Ｙへの送りが停止する。底部２１は回転軸２６方向から見て直径方向に一対の第四切り刃２２と、第四切り刃２２の切り屑を排出する切り屑排出溝であって一方が第一切り屑排出溝１２に連なり他方が第二切り屑排出溝１３に連なる一対の第四切り屑排出溝２３とを備えている。各第四切り刃２２は底部２１に連なる側の端部から送り方向Ｙ側の端部へいくにつれて回転軸２６に近づくよう回転軸２６に対して傾斜しており、これら一対の第四切り刃２２は小径の加工穴の開口縁部の面取りを行う。尚、内部に小径の加工穴が無い、あるいは小径の加工穴の面取りを行わないのであればそれら一対の第四切り刃２２及び一対の第四切り屑排出溝２３を備えることは不要である。
【００２５】
第三逃げ面１９は底部２１に連なり、概ね円柱曲面状である。第三逃げ面１９と第二切り屑排出溝１３の壁面とは稜線部を形成しており、その稜線部に第三切り刃２０が形成されている。すなわち、第三逃げ面１９は、第三切り刃２０の相対回転方向２７後方に連なっている。第三切り刃２０は逃がし部の凹み部１６ａの相対回転方向２７後方に設けられており、本実施例では具体的には回転軸２６を挟んで逃がし部の凹み部１６ａに対向する側に設けられている。
【００２６】
第三切り刃２０は回転軸２６に概ね平行に形成されており、第三切り刃２０の回転軸２６に対する傾斜角度は第二切り刃１８の回転軸２６に対する傾斜角度と同じ角度である。尚、第三切り刃２０は第二切り刃１８と同様に切削をスムーズに行うために回転軸２６に対して相対回転方向２７に傾斜していてもよい。図３は図１（Ａ）に示す穴明けボーリングバイト１０を更に拡大して示す図である。尚、理解を容易にするため、図３においては第四切り屑排出溝２３や、第二切り屑排出溝１３と第一逃げ面１４との稜線部の一部などは省略している。図３に示すように、第三切り刃２０は稜線部２５全域に渡って形成されており、第三切り刃２０を回転軸２６へ垂直に投影した切り刃領域Ｘには、逃がし部の凹み部１６ａを回転軸２６へ垂直に投影した逃がし部領域Ｚが含まれている。ここで切り刃領域Ｘは、第三切り刃２０の底部２１側の端部を通り回転軸２６に垂直な直線Ｌ１と回転軸２６との交点と、第三切り刃２０の後端部側の端部を通り回転軸２６に垂直な直線Ｌ２と回転軸２６との交点とで挟まれる領域である。逃がし部領域Ｚも同様に直線Ｌ３及び直線Ｌ４の交点で挟まれる領域である。第三切り刃２０は回転軸２６を挟んで凹み部１６ａに対向する側に設けられていることから、回転軸２６に直交する面上において回転軸２６を中心に凹み部１６ａと第三切り刃２０とで形成される角度は１８０度となる。従って、穴明けボーリングバイト１０を被削材に対して相対回転させると、凹み部１６ａによって生じたばりは１８０度相対回転した時点で稜線部２５に到達する。ここで例えば所定の送り量をＶｍｍとすると、穴明けボーリングバイト１０が１８０度相対回転する間に送り方向Ｙに相対移動する距離はＶ／２ｍｍとなる。従って、逃がし部領域Ｚの後端部側の端部から切り刃領域Ｘの後端部側の端部までの領域を領域Ｕとすると、領域Ｕの長さがＶ／２ｍｍ以上であれば穴明けボーリングバイト１０が相対回転しつつ送り方向Ｙへ送られる間も第三切り刃２０は稜線部２５に到達したばりを切削できることになる。図示するように本実施例の領域ＵはＶ／２ｍｍ以上である。従って穴明けボーリングバイト１０が相対回転しつつ送り方向Ｙへ送られる間も稜線部２５に到達したばりは第三切り刃２０によって切削される。底部２１が加工穴の底壁に当接して送り方向Ｙへの送りが停止したとき、ばりは逃がし部の溝部１６ｂに沿って加工穴の稜線部に概ね１／２周する長さで螺旋状に残った状態となる。この状態で穴明けボーリングバイト１０を相対回転させるとばりは回転軸２６に垂直な方向に相対的に進行することになり、残ったばりは、回転軸２６において逃がし部領域Ｚの底部２１側の端部と、逃がし部領域Ｚの後端部側の端部から後端部側にＶ／２ｍｍ離れた位置とで挟まれる領域に対応する第三切り刃２０の領域Ｍ全体で切削される。
【００２７】
尚、本実施例の第三切り刃２０は底部２１まで延び、底部２１に連なっている。これにより第三切り刃２０は第二切り刃１８と同様に加工穴の内周壁の切削も併せて行っているが、回転軸２６において逃がし部領域Ｚの底部２１側の端部より底部２１側の領域に対応する第三切り刃２０の領域Ｈには切り刃を形成しなくてもよい。その場合、加工穴内周壁の切削は第一切り刃１５のみによって行われることになる。また、回転軸２６において逃がし部領域Ｚの後端部側の端部から後端部側の領域に対応する第三切り刃２０の領域Ｋにも切り刃が形成されているが、領域Ｋには切り刃を形成しなくてもよい。この場合、穴明けボーリングバイト１０が送り方向に進行している間は逃がし部によって生じたばりは第一切り刃１５が次に相対回転してきたとき加工穴の開口縁部と供に第一切り刃１５によって切削される。底部２１が加工穴の底壁に当接して送り方向Ｙへの送りが停止した状態で穴明けボーリングバイト１０を相対回転させると、螺旋状に残ったばりは第一切り刃１５が次に相対回転してきたとき加工穴の開口縁部と供に第一切り刃１５によって切削され、逃がし部に入り込んで第一切り刃１５が切削することのできないばりは第三切り刃２０によって切削される。
【００２８】
以上説明したように、本実施例の穴明けボーリングバイト１０は従来の穴明けボーリングバイト３０と同様、第一切り刃１５と第二切り刃１８との境界に凹み部１６ａを備える。これにより第一切り刃１５と第二切り刃１８との間に生じるＲ形状を取り除いている。しかしながら、凹み部１６ａを設けたことで被削材の第一切り刃１５によって形成された面と第二切り刃１８によって形成された面との稜線部に図４（Ａ）に示すようにばり２４が生じる。本実施例の穴明けボーリングバイト１０は凹み部１６ａに対向する側に第三切り刃２０を備えていることから、生じたばりは図４（Ｂ）に示すように第三切り刃２０によって切削され除去される。よって本実施例の穴明けボーリングバイト１０によると、穴明け加工の過程で生じるばりを穴明け加工をしつつ除去できる。従って除去のための高額設備、ブラシ類を用いた除去作業、検査器を使ったばりの有無の確認などが不要になり、ばりの除去や検査に費やす費用を低減できる。
【図面の簡単な説明】
【図１】Ａは本発明の一実施例による穴明け工具の一部を拡大して示す図であり、ＢはＡに示す穴明け工具を逆方向から見た図である。
【図２】本発明の一実施例による穴明け工具を示す図である。
【図３】図１（Ａ）に示す穴明け工具の一部を拡大して示す模式図である。
【図４】Ａは本発明の一実施例による穴明け工具の逃がし部を示す図であり、Ｂは第三切り刃を示す図である。
【図５】Ａは従来の穴明け工具の一部を示す図であり、ＢはＡに示す穴明け工具の一部を拡大して示す図である。
【符号の説明】
１　第一切り刃
２　第二切り刃
３　逃がし部
１０　穴明けボーリングバイト（穴明け工具）
１１　シャンク部
１２　第一切り屑排出溝
１３　第二切り屑排出溝
１４　第一逃げ面
１５　第一切り刃
１６ａ　凹み部（逃がし部）
１６ｂ　溝部（逃がし部）
１７　第二逃げ面
１８　第二切り刃
１９　第三逃げ面
２０　第三切り刃
２１　底部（先端部）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drilling tool.
[0002]
[Prior art]
A drilling tool as a cutting tool is used for the purpose of machining the inner peripheral shape of a machining hole of a work material into the same shape as the outer peripheral shape of the tool. There are various shapes of drilling tools, and ones having shapes according to applications such as chamfering, inner diameter processing, bottom processing, and the like are properly used.
[0003]
FIG. 5A is a diagram showing an example of a drilling boring tool 30 which is one of the conventional drilling tools. The boring boring tool 30 in the illustrated example performs a chamfering process on an opening edge of a processing hole of the work material 31 and an inner diameter processing for cutting an inner peripheral wall of the processing hole, and a processing hole 33 having a smaller diameter is formed on a bottom wall. With respect to the existing machining holes, the edge of the opening of the small-diameter machining hole 33 is also chamfered. In the case of a drilling boring tool 30 for chamfering the opening edge and cutting the inner peripheral wall, an R-shape is formed at the intersection P between the first cutting blade 1 for chamfering and the second cutting blade 2 for cutting the inner peripheral wall. As a result, there is a problem that even in the work material, the R shape remains at the ridge line between the surface formed by the first cutting blade 1 and the surface formed by the second cutting blade 2. For this reason, in the conventional boring tool 30, the relief portion 3 is provided at the intersection P of the first cutting edge 1 and the second cutting edge 2 so as not to generate an R shape at the ridge portion of the work material. The provision of the relief portion 3 removes the R shape at the intersection P, thereby preventing the R shape from being formed at the ridge line of the work material.
[0004]
[Problems to be solved by the invention]
However, when the relief portion is provided, there is a problem that a part of the work material that has entered the relief portion remains as a flash.
[0005]
FIG. 5B is an enlarged view showing a part of the drilling boring tool 30. As shown in the drawing, the relief portion 3 is provided between the first cutting edge 1 and the second cutting edge 2, so that a part of the work material that has entered the relief portion 3 is cut by either cutting edge. And finally remains as burrs 4.
[0006]
The problems caused by burrs are many and can lead to significant losses in some cases. Therefore, there is a strong demand for the removal of burrs during processing and the suppression of burrs.In the past, expensive dedicated equipment for removal was introduced, removal work was performed using brushes, and burrs were used with inspection equipment. A lot of money is spent on removing and inspecting burrs, such as checking for the presence or absence of burrs.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a drilling tool capable of removing a burr generated during a drilling process while performing the drilling.
[0008]
[Means for Solving the Problems]
In the drilling tool according to the first aspect, a concave relief portion is provided at a boundary between the first cutting edge and the second cutting edge. As a result, the round shape generated between the first cutting edge and the second cutting edge is removed. However, the provision of the relief portion causes burrs at the ridge line between the surface formed by the first cutting blade and the surface formed by the second cutting blade of the work material. A third cutting edge whose inclination angle with respect to the rotation axis is equal to the inclination angle of the second cutting edge is formed behind the relief portion of the drilling tool according to claim 1 in the relative rotation direction. The cutting edge region projected perpendicular to the rotation axis includes a relief portion region perpendicularly projecting the relief portion to the rotation axis. Therefore, if the drilling tool rotates around the rotation axis with the tip of the drilling tool abutting on the drilled hole and the feed in the feed direction of the drilling tool is stopped, the flash generated by the relief part will be the third cut. It is cut by a blade. Therefore, according to the drilling tool of the first aspect, it is possible to remove burrs generated in the work material during the drilling process while performing the drilling process.
[0009]
The drilling tool according to claim 2, wherein a length from a rear end side end of the relief area to a rear end side end of the cutting blade area is a rotation axis on a plane orthogonal to the rotation axis. And the angle formed by the relief portion and the third cutting edge is at least as long as the distance that the drilling tool relatively moves in the feed direction during the relative rotation. Therefore, according to the drilling tool of the second aspect, the burrs can be cut by the third cutting blade even while the drilling tool is relatively rotated while being fed in the feed direction.
[0010]
According to the drilling tool according to claim 3, the surface formed by the first cutting edge, the surface formed by the second cutting edge, and the surface formed by the third cutting edge of the work material, and the drilling tool. Unnecessary contact can be avoided.
[0011]
According to the drilling tool of the fourth aspect, chips generated by the first cutting edge, the second cutting edge, and the third cutting edge can be discharged.
According to the drilling tool of the fifth aspect, chips generated by the first cutting edge, the second cutting edge, and the third cutting edge can be more smoothly discharged.
[0012]
According to the drilling tool of the present invention, the generated burrs relatively advance along the groove, so that the drilling tool can rotate relatively without contacting the burrs. Therefore, there is no need to largely release the first flank and the second flank in order to prevent contact with the burrs, and the strength of the first cutting blade and the second cutting blade can be maintained.
[0013]
According to the drilling tool of the seventh aspect, the inner peripheral wall of the processing hole can be cut not only by the first cutting edge but also by the third cutting edge.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 is a diagram showing a drilling tool according to one embodiment of the present invention. The drilling tool according to the present embodiment is a drilling boring tool 10 for performing a drilling operation on a processing hole previously opened in a work material. The diameter of the machined hole is smaller than the radius from the rotating shaft 26 of the drilling boring tool 10 to the second cutting edge 18 described later. The boring boring tool 10 performs a chamfer by cutting the opening edge of the processing hole by rotating relatively to the work material by a predetermined feed amount, and also cutting the inner peripheral wall of the processing hole to reduce the inner diameter of the inner peripheral wall. The inner diameter of the hole is machined into the same shape as the outer shape of the boring tool 10. Here, the feed amount means a relative movement amount in the feed direction per one rotation. For example, when the feed amount is moved by Vmm in one rotation, the feed amount is Vmm. In the present embodiment, a processing hole having a step inside the processing hole and an inner diameter of the processing hole being reduced in the middle, that is, a processing hole in which a processing hole having a smaller diameter exists in the bottom wall of the processing hole, A drilling boring tool 10 that also performs chamfering of an opening edge of a processing hole will be described as an example. For this reason, a pair of cutting blades for chamfering a small-diameter machined hole is provided at the tip of the boring tool 10 of this embodiment.
[0015]
1A is an enlarged view of the drilling boring tool 10, and FIG. 1B is a view of the drilling boring tool 10 shown in FIG. 1A as viewed from the opposite direction. The drilling boring tool 10 is made of a cemented carbide, and has a shank portion 11, a first chip discharge groove 12, a second chip discharge groove 13, a first flank 14, a first cutting blade 15, a relief portion, and a second relief. The surface 17, the second cutting blade 18, the third flank 19, the third cutting blade 20, the bottom 21 as a tip, a pair of fourth cutting blades 22, and a pair of chip discharge grooves 23 are provided.
[0016]
The shank portion 11 has a cylindrical shape, and when used, the shank portion 11 is held and rotated by, for example, a machine tool. Thereby, the shank part 11 rotates around the rotation axis 26. Here, the direction 27 indicates the direction of relative rotation of the drilling boring tool 10 with respect to the workpiece.
[0017]
From the bottom 21 of the drilling boring tool 10, a first chip discharge groove 12 for discharging chips of the first cutting blade 15 and the second cutting blade 18, and a second chip for discharging chips by the third cutting blade 20. A waste discharge groove 13 is formed. The first chip discharge groove 12 is formed between the bottom 21 of the drilling boring tool 10, between the second cutting edge 18 and the third flank 19, a recess 16 a as a flank, a groove 16 b, and the third flank 19. , And further extends between the first cutting edge 15 and the third flank 19 by being spirally twisted in a direction opposite to the relative rotation direction 27 toward the rear end of the boring tool 10. Similarly, the second chip discharge groove 13 relatively rotates between the second flank 17 and the third cutting blade 20 and further between the first flank 14 and the third cutting blade 20 toward the rear end. It extends spirally in a direction opposite to the direction 27. Since the first chip discharge groove 12 and the second chip discharge groove 13 are twisted in the same direction, they do not cross each other. The first chip discharge groove 12 and the second chip discharge groove 13 may extend to the rear end without being twisted.
[0018]
The first flank 14 is continuous with the shank portion 11 and extends in a generally conical curved shape by being twisted toward the rear end. The first flank 14 and the wall surface of the first chip discharge groove 12 form a ridge, and the first cutting edge 15 is formed on the ridge. That is, the first flank 14 continues to the rear of the first cutting edge 15 in the relative rotation direction 27.
[0019]
The end E of the first cutting blade 15 is connected to the shank 11 as shown. Therefore, the first cutting edge 15 is formed closer to the tip end than the shank portion 11. The first cutting blade 15 is inclined at a predetermined inclination angle with respect to the rotating shaft 26 so as to approach the rotating shaft 26 as going from the end E connected to the shank portion 11 to the other end F on the bottom 21 side. It is formed with a cutting edge angle. The first cutting edge 15 is for cutting the opening edge of the processing hole of the work material, and the first cutting edge 15 is rotated by relatively rotating the boring boring tool 10 and the work material. Is cut, whereby the chamfering is performed to form a surface at the opening edge of the work material.
[0020]
The escaping portion is provided with a dent portion 16a provided in an end portion on the tip end side of the first cutting blade 15, and a rear end between the first flank surface 14 and the second flank surface 17 from the dent portion 16a. And a groove portion 16b extending in a groove shape toward the portion. FIG. 4A is an enlarged view showing a relief portion. As shown in the figure, the boundary between the first cutting edge 15 and the second cutting edge 18, that is, the intersection Q is provided with a concave portion 16a instead of an R shape. By providing the concave portion 16a, there is no R shape between the first cutting blade 15 and the second cutting blade 18, whereby the surface of the work material formed by the first cutting blade 15 and the second cutting blade 18 The formation of an R-shape at the ridge line with the surface of the workpiece to be formed is prevented. However, since the recess 16a is provided between the first cutting blade 15 and the second cutting blade 18, a part of the work material that has entered the recess 16a may be cut by either cutting blade. Therefore, a part of the work material that has entered the recess 16a remains as a burr 24. As a result, burrs 24 are generated by the relief portion. When the drilling boring tool 10 is sent while rotating, the generated burrs 24 reach the third cutting edge 20 without contacting the drilling boring tool 10 by relatively moving along the groove 16b. The shape of the groove 16b is such that when the bottom 21 abuts against the bottom wall of the drilled hole and the drilling boring tool 10 stops feeding in the feed direction Y, the remaining burrs are drilled in a direction perpendicular to the rotating shaft 26. It is formed in a shape that reaches the third cutting edge 20 without contacting the boring tool 10. Note that the first flank 14 and the second flank 17 are largely escaping, and the groove 16b may not be provided if the burrs 24 do not contact the drilling boring tool 10 without providing the groove 16b.
[0021]
As shown in FIGS. 1A and 1B, the second flank 17 is connected to the bottom 21 and has a substantially cylindrical curved surface. The second flank 17 and the wall surface of the first chip discharge groove 12 form a ridge, and the second cutting blade 18 is formed on the ridge. That is, the second flank 17 is continuous with the second cutting blade 18 in the relative rotation direction 27 rearward.
[0022]
The second cutting blade 18 has one end connected to the bottom 21, the other end connected to the recess 16 a of the relief portion, and is substantially parallel to the rotating shaft 26 and has no step. Here, “substantially parallel to the rotation shaft 26” means that it is inclined in the relative rotation direction 27 with respect to the rotation shaft 26 by a predetermined angle in order to perform cutting smoothly. Since the second cutting edge 18 is substantially parallel to the rotation axis 26, the inclination angle of the second cutting edge 18 with respect to the rotation axis 26 is approximately 0 degrees. Since the inclination angle of the first cutting edge 15 with respect to the rotating shaft 26 of this embodiment is approximately 45 degrees as shown in FIG. 1A, the inclination angle of the second cutting edge 18 with respect to the rotating shaft 26 is equal to the first cutting edge. 15 is smaller than the inclination angle with respect to the rotation shaft 26. The second cutting blade 18 cuts the inner peripheral wall of the processing hole opened in the work material at the time of processing, and enlarges the inner diameter of the processing hole.
[0023]
Although the second cutting edge 18 of the present embodiment is substantially parallel to the rotation axis 26, the second cutting edge 18 may be inclined with respect to the rotation axis 26 so as to approach the rotation axis 26 toward the bottom 21. Good. In this case, the inclination angle of the second cutting blade 18 with respect to the rotation axis 26 may be any angle as long as it is smaller than the inclination angle of the first cutting blade 18 with respect to the rotation axis 26, and the inclination angle depends on the shape of the machining hole. It may be changed as appropriate. The second cutting edge 18 is inclined with respect to the rotating shaft 26 so as to approach the rotating shaft 26 as it goes to the bottom 21 side, and is inclined with respect to the rotating shaft 26 in a relative rotation direction 27 in order to perform cutting smoothly. May be.
[0024]
The bottom 21 as a tip has a surface that contacts the bottom wall of the machined hole and a surface that is continuous with the surface and twists toward the rear end in a conical curved shape. When the bottom portion 21 contacts the bottom wall of the machined hole, the feed of the drilling boring tool 10 in the feed direction Y is stopped. The bottom portion 21 is a pair of fourth cutting blades 22 in the diameter direction when viewed from the rotation shaft 26 direction, and a chip discharging groove for discharging the chips of the fourth cutting blade 22, one of which is in the first chip discharging groove 12. There is a pair of fourth chip discharge grooves 23 that are continuous and the other is connected to the second chip discharge groove 13. Each of the fourth cutting blades 22 is inclined with respect to the rotating shaft 26 so as to approach the rotating shaft 26 from the end on the side connected to the bottom 21 to the end on the feeding direction Y side. 22 chamfers the opening edge of the small diameter processing hole. It is unnecessary to provide the pair of fourth cutting blades 22 and the pair of fourth chip discharge grooves 23 if there is no small-diameter processing hole inside or if the small-diameter processing hole is not chamfered.
[0025]
The third flank 19 is continuous with the bottom 21 and has a substantially cylindrical curved surface. The third flank 19 and the wall surface of the second chip discharge groove 13 form a ridge, and a third cutting edge 20 is formed on the ridge. That is, the third flank 19 is continuous with the third cutting blade 20 in the relative rotation direction 27 rearward. The third cutting blade 20 is provided behind the concave portion 16a of the relief portion in the relative rotation direction 27. Specifically, in this embodiment, the third cutting edge 20 is provided on the side facing the concave portion 16a of the relief portion with the rotating shaft 26 interposed therebetween. Have been.
[0026]
The third cutting blade 20 is formed substantially parallel to the rotating shaft 26, and the inclination angle of the third cutting blade 20 with respect to the rotating shaft 26 is the same as the inclination angle of the second cutting blade 18 with respect to the rotating shaft 26. Incidentally, the third cutting blade 20 may be inclined in the direction of relative rotation 27 with respect to the rotating shaft 26 in order to smoothly perform cutting like the second cutting blade 18. FIG. 3 is an enlarged view of the drilling boring tool 10 shown in FIG. In FIG. 3, the fourth chip discharge groove 23 and a part of the ridge line between the second chip discharge groove 13 and the first flank 14 are omitted in FIG. As shown in FIG. 3, the third cutting edge 20 is formed over the entire area of the ridgeline portion 25, and the cutting edge region X in which the third cutting edge 20 is projected perpendicularly to the rotation shaft 26 has a recess of a relief portion. A relief portion area Z in which the portion 16a is projected perpendicular to the rotation axis 26 is included. Here, the cutting edge region X is defined by the intersection of the rotation axis 26 with a straight line L1 passing through the bottom 21 side end of the third cutting edge 20 and the rotation axis 26, and the rear end side of the third cutting edge 20. This is an area sandwiched between the straight line L2 passing through the end and perpendicular to the rotation axis 26 and the intersection of the rotation axis 26. Similarly, the relief portion area Z is an area sandwiched between the intersections of the straight lines L3 and L4. Since the third cutting blade 20 is provided on the side opposed to the concave portion 16a with the rotary shaft 26 interposed therebetween, the concave portion 16a and the third cutting blade around the rotary shaft 26 on a plane orthogonal to the rotary shaft 26. The angle formed by 20 is 180 degrees. Therefore, when the drilling boring tool 10 is rotated relative to the work material, the burrs generated by the recessed portions 16a reach the ridgeline portions 25 at the time of the relative rotation of 180 degrees. Here, for example, assuming that the predetermined feed amount is Vmm, the distance that the drilling boring tool 10 relatively moves in the feed direction Y during the relative rotation of 180 degrees is V / 2 mm. Accordingly, if the area from the rear end side end of the relief section area Z to the rear end side end of the cutting edge area X is defined as the area U, if the length of the area U is V / 2 mm or more, a hole is formed. The third cutting edge 20 can cut the burrs that have reached the ridgeline portion 25 even while the dawn boring tool 10 is fed in the feed direction Y while rotating relatively. As shown in the drawing, the area U of this embodiment is equal to or more than V / 2 mm. Therefore, the burrs that have reached the ridgeline portion 25 are also cut by the third cutting blade 20 while the drilling boring tool 10 is being fed in the feed direction Y while rotating relatively. When the bottom portion 21 abuts on the bottom wall of the processing hole and the feeding in the feeding direction Y is stopped, the burrs are spirally formed along the groove portion 16b of the relief portion so as to make approximately a half turn around the ridge line portion of the processing hole. Will be left in the state. When the drilling boring tool 10 is relatively rotated in this state, the burrs relatively advance in the direction perpendicular to the rotating shaft 26, and the remaining burrs are formed on the rotating shaft 26 on the bottom 21 side of the relief portion area Z. The entire region M of the third cutting edge 20 corresponding to the region sandwiched between the end and the position V / 2 mm away from the rear end of the relief region Z toward the rear end from the rear end is cut.
[0027]
Note that the third cutting edge 20 of the present embodiment extends to the bottom 21 and is connected to the bottom 21. As a result, the third cutting edge 20 also cuts the inner peripheral wall of the processing hole in the same manner as the second cutting edge 18, but the rotation shaft 26 is closer to the bottom 21 than the end of the relief region Z on the bottom 21 side. The cutting edge may not be formed in the region H of the third cutting blade 20 corresponding to the region of (3). In that case, the cutting of the inner peripheral wall of the processing hole is performed only by the first cutting edge 15. The cutting edge is also formed in the area K of the third cutting edge 20 corresponding to the area from the rear end side to the rear end side of the relief section area Z on the rotating shaft 26. Does not have to form a cutting edge. In this case, while the drilling boring tool 10 is advancing in the feed direction, the burrs generated by the escaping portion will be removed together with the opening edge of the drilled hole when the first cutting blade 15 is next rotated relatively. It is cut by the blade 15. When the drilling boring tool 10 is relatively rotated in a state where the bottom portion 21 is in contact with the bottom wall of the processing hole and the feed in the feed direction Y is stopped, the burrs remaining in a spiral form have the first cutting edge 15 which is then relatively rotated. When it rotates, it is cut by the first cutting edge 15 together with the opening edge of the processing hole, and the burrs that enter the relief portion and cannot be cut by the first cutting edge 15 are cut by the third cutting edge 20.
[0028]
As described above, the drilling boring tool 10 of the present embodiment includes the recess 16a at the boundary between the first cutting edge 15 and the second cutting edge 18 as in the case of the conventional drilling boring tool 30. Thereby, the round shape generated between the first cutting edge 15 and the second cutting edge 18 is removed. However, since the recess 16a is provided, the ridge line between the surface formed by the first cutting blade 15 and the surface formed by the second cutting blade 18 of the work material has burrs as shown in FIG. 24 results. Since the drilling boring tool 10 of this embodiment has the third cutting edge 20 on the side facing the recess 16a, the generated burrs are cut by the third cutting edge 20 as shown in FIG. Is removed. Therefore, according to the drilling boring tool 10 of the present embodiment, burrs generated during the drilling process can be removed while performing the drilling. Therefore, it is not necessary to use expensive equipment for removal, removal work using brushes, and check for the presence or absence of burrs using an inspection device, and the cost for removing or inspecting burrs can be reduced.
[Brief description of the drawings]
FIG. 1A is an enlarged view of a part of a drilling tool according to an embodiment of the present invention, and FIG. 1B is a view of the drilling tool shown in A viewed from a reverse direction.
FIG. 2 is a diagram illustrating a drilling tool according to an embodiment of the present invention.
FIG. 3 is a schematic diagram showing an enlarged part of the drilling tool shown in FIG.
FIG. 4A is a diagram illustrating a relief portion of a drilling tool according to an embodiment of the present invention, and FIG. 4B is a diagram illustrating a third cutting edge.
5A is a diagram showing a part of a conventional drilling tool, and FIG. 5B is a diagram showing a part of the drilling tool shown in A in an enlarged manner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 First cutting edge 2 Second cutting edge 3 Relief part 10 Drilling boring tool (drilling tool)
11 shank portion 12 first chip discharge groove 13 second chip discharge groove 14 first flank 15 first cutting blade 16a recess (relief portion)
16b Groove (Escape)
17 second flank 18 second cutting blade 19 third flank 20 third cutting blade 21 bottom (tip)

Claims

A drilling tool that cuts an inner peripheral wall of the work material by relatively rotating with respect to the work material,
A shank part that rotates around the rotation axis,
A first cutting blade formed at a tip end side from the shank portion and inclined at a predetermined inclination angle with respect to the rotation axis so as to approach the rotation axis toward the tip end side,
A concave relief portion provided at an end portion on the tip end side of the first cutting blade,
Inclining with respect to the rotation axis so as to be closer to the rotation axis as it is connected to the relief portion and substantially parallel to the rotation axis or toward the tip end side, the inclination angle with respect to the rotation axis is the inclination angle of the first cutting blade. A smaller second cutting edge,
A third cutting edge whose inclination angle with respect to the rotation axis is equal to the inclination angle of the second cutting edge, provided in a relative rotation direction rear of the relief portion, and vertically extending the third cutting edge to the rotation axis. Projected cutting edge region, the third cutting edge including a relief portion region projected the relief portion perpendicular to the rotation axis,
A drilling tool comprising:

The third cutting edge has a length from an end on a rear end side of the relief portion area to an end on a rear end side of the cutting edge area, and the rotation axis is on a plane orthogonal to the rotation axis. Wherein the angle formed by the relief portion and the third cutting edge with respect to the center is at least as long as the distance that the drilling tool relatively moves in the feed direction during relative rotation. The drilling tool according to 1.

A first flank connected to the relative rotational direction rear of the first cutting blade,
A second flank that continues rearward in the relative rotation direction of the second cutting blade,
A third flank face that is connected to the rear of the third cutting blade in the relative rotation direction,
The drilling tool according to claim 1 or 2, further comprising:

The first cutting edge, the relief portion and the second cutting edge, a first chip discharge groove extending from the front end portion to the rear end portion between the third flank,
The first flank and the second flank, a second chip discharge groove extending from the front end to the rear end between the third cutting edge,
The drilling tool according to claim 3, further comprising:

The drilling tool according to claim 4, wherein the first chip discharge groove and the second chip discharge groove are twisted and extend toward a rear end in a direction opposite to a relative rotation direction.

The perforation according to claim 3, 4 or 5, wherein the relief portion extends in a groove shape between the first flank and the second flank toward a rear end. tool.

The drilling tool according to any one of claims 1 to 6, wherein an end on the tip end side of the third cutting blade is continuous with the tip.