JP2004283970A

JP2004283970A - Deep hole cutting tool

Info

Publication number: JP2004283970A
Application number: JP2003079996A
Authority: JP
Inventors: Takuji Nomura; 倬司野村
Original assignee: Unitac Inc
Current assignee: Unitac Inc
Priority date: 2003-03-24
Filing date: 2003-03-24
Publication date: 2004-10-14
Anticipated expiration: 2023-03-24
Also published as: JP4141297B2

Abstract

<P>PROBLEM TO BE SOLVED: To secure the easiness of precise manufacturing and the sufficient strength of a shank by well designing the formation of a coolant feed passage and a coolant discharge groove or the structure of the shank, and to improve chip discharging capability by the coolant. <P>SOLUTION: A through hole 7 is axially formed at the whole area concentrically with the shank 3, and the through hole 7 forms the coolant feed passage 2. A part of the outer peripheral wall of the shank 3 is axially cut off linearly at the whole area avoiding the through hole, and the cut-off part 8 forms the coolant discharge groove 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、ガンドリルシステムに適用されるドリルやリーマなどの深孔切削具に関するものである。
【０００２】
【従来の技術】
深孔加工システムとして、ガンドリルシステム、ＢＴＡシステム、エジェクタシステムなどが知られているが、比較的小径の深孔加工には簡単な構成のガンドリルシステムが汎用されている。
【０００３】
ガンドリルシステムとして、一般的に例えば特許文献１或いは同２に掲げる従来技術を挙げることができる。この構造を図６の（Ａ）によって説明すると、中空筒状で外面に長手方向に沿う断面Ｖ字状の凹溝３４を形成したシャンク軸３１の先端にドリルヘッド３２を一体的に固着し、そのシャンク軸３１の中空部内をクーラントＣの供給通路３３とし、凹溝を切屑Ｓの排出溝３４としたガンドリル３０を用い、深孔加工時に、高圧のクーラントＣを供給通路３３を通してドリルヘッド３２の先端側より吐出させ、被加工物Ｗの切削孔Ｈ内で発生した切屑Ｓを当該クーラントＣと共に排出溝３４を通して外部に排出するように構成されている。
【０００４】
【特許文献１】
特公昭５９−１２４０５号公報
【特許文献２】
実開昭６０−５３４１６号公報
【０００５】
上記のガンドリルシステムに使用されるガンドリルとしては、同（ｂ）の断面図に示すように、シャンク軸３１の中空部内をクーラントＣの供給通路３３ａ，３３ｂを形成すると共に、該シャンク軸３１の切除断面がシャンク軸心Ｏを中心として略９０度のＶ字状をなすようにして軸方向略全域に切除してクーラントの排出溝３４を形成しており、このようにクーラントの排出溝３４の排出面積を大きく取りクーラントの排出能力を余裕を持って設けるようにしている。その反面、シャンク軸３１の軸心付近に形成されるクーラントＣの供給通路３３ａ，３３ｂの断面積を強度上の理由から余り大きく取ることができず、それがために、例えクーラントの排出面積を大きく取ってその排出能力を上げても、クーラントＣの供給能力に限界があるため、結局のところ、被加工物Ｗの切削孔Ｈ内で発生した切屑Ｓを当該クーラントＣと共に排出溝３４を通して外部に排出する排出能力に一定の限界があった。
【０００６】
しかも、前述のように、シャンク軸３１の断面積の略４分の１をその軸心Ｏを中心として切除してクーラントの排出溝３４の断面積は大きく取るようになっているため、シャンク軸３１の軸心付近に形成されるクーラント供給通路３３ａ，３３ｂは、図示のようにシャンク軸３１の軸心Ｏを避けて小径の単独又は複数の貫通通路３３ａ，３３ｂとならざるを得ず、これがためにシャンク軸３１の長さが１．５メートルを超えると孔明け加工において貫通通路３３ａ，３３ｂの直進性を維持することが困難で、その製作面で問題があった。
【０００７】
【発明が解決しようとする課題】
本発明は、以上の課題に鑑みなされたものであり、クーラントの供給通路とクーラントの排出溝の形成あるいはシャンク軸の構造に工夫を凝らすことにより、シャンク軸の充分な強度の確保と精度良好な製作の容易性を確保し、併せてクーラントによる切屑の排出能力を向上させることを目的とするものである。
【０００８】
【課題を解決するための手段】
上記目的を達成するために、請求項１に係る発明は、実施形態に示す参照符号を付して示すと、外周部にはクーラントの排出溝１が設けられ内部にはクーラントの供給通路２が設けられたシャンク軸３と、シャンク軸３の先端部に切削ヘッド４を備える深孔切削具であって、前記シャンク軸３に同心に略軸方向全域に貫通孔７が設けられて該貫通孔７が上記クーラントの供給通路２を形成し、シャンク軸３の外周壁の一部が前記貫通孔７を避けて略軸方向全域に直線状に切除されて該切除部８が上記クーラントの排出溝１を形成してなることを特徴とする構成からなるものである。
【０００９】
請求項１に係る発明によれば、まず、シャンク軸３に同心に略軸方向全域に貫通孔７が設けられて、該貫通孔７を利用して、これをクーラントの供給通路２としたため、該供給通路の製作が容易である。なお、このシャンク軸３は、後述のように複数のシャンク軸部材９が互いにねじ結合されて形成される場合以外に、長尺の一本のシャンク軸からなる場合にも適用されることは勿論である。
【００１０】
製作上において、中実丸軸部材の中心部を穿孔して貫通孔７を形成する場合にあっても、中実丸軸部材の同心（軸心）に貫通孔７を形成する際に、中実丸軸部材と孔明け工具との相対回転によって孔明け作業を行うことが可能であり、このため中実丸軸部材が１．５メートルを超える長尺部材であっても直進性の優れたクーラント供給通路である貫通孔を形成することができ、精度良好な深孔切削具を容易に製作することができる。
【００１１】
更に、シャンク軸３に同心に貫通孔７を形成し、この貫通孔７をクーラント供給通路２となすため、クーラント供給通路２を大径に形成することが可能となり、それだけクーラントの供給能力を向上させることができる。このように、クーラント供給通路２を大径に形成しても、後述のようにシャンク軸３が外周壁を一部切除して形成されるクーラント排出溝１の断面積を出来るだけ小さくとることによって、必要充分な軸強度を確保することができる。
【００１２】
そして、シャンク軸３の外周壁の一部を前記貫通孔７を避けて、即ち貫通孔７に連通しないようにして略軸方向全域を切除して、この切除部８をクーラント及び切屑の排出溝１となしたため、製作上からはシャンク軸３の一部を軸方向に切削するだけでよいからその製作が容易である。
【００１３】
そしてまた、シャンク軸３の外周壁の一部を前記貫通孔７を避けて切除することによって、該切除部８の底部には貫通孔７の外周面８ａの一部が露出することになり、従って、該切除部８は前記貫通孔７の露出した外周面５ａとシャンク軸３の一部を切除した切除端面８ｂ，８ｃとに囲繞された空隙部によって形成され、該切除部８は大径に形成された貫通孔７の外側に形成されるため、従来のシャンク軸の軸心を通る断面Ｖ字状のクーラント排出溝の断面積にくらべて、その断面積が小さくなるが、上述のようにクーラントの供給通路２のクーラント供給能力が向上することと相まって、クーラントの排出溝の断面積が多少小さくなっても、むしろクーラントの流速が速くなり、切屑の排出能力が格段に向上させことができる。
【００１４】
また請求項２に係る発明は、前記シャンク軸３は、先端部に切削ヘッド４がねじ結合により着脱可能に設けられてなる請求項１に記載の構成からなるものである。
【００１５】
請求項２に係る発明によれば、切削ヘッド４がシャンク軸３から着脱可能に設けられることによって、切削ヘッド４あるいはシャンク軸３の摩耗や欠損等で何れか一方を取り替える必要がある場合に、従来の切削ヘッドとシャンク軸との一体のものに比べて、摩耗や欠損した上記部品のみを交換すればよいからそれだけ修理費用が安価につく。
【００１６】
更にはドリリングとリーミングのように他の切削作業に切り換えたりする場合には、この切削ヘッド４のみを交換し、シャンク軸３を継続使用することができる。
【００１７】
このように切削ヘッド４がシャンク軸３がねじ結合によって連結されるようになっているため、両者の連結構造が簡単で安価に製作することが可能であり、且つ摩耗や欠損時の何れか一方の部品の交換作業を容易に行うことができる。
【００１８】
また請求項３に係る発明は、前記シャンク軸３は、複数のシャンク軸部材９からなり、各シャンク軸部材９は互いに着脱可能にねじ結合されてなる請求項１又は２に記載の構成からなるものである。
【００１９】
請求項３に係る発明によれば、シャンク軸３が複数の互いにねじ結合された複数のシャンク軸部材９からなるため、各シャンク軸部材９として長さの異なる複数本を用意しておけば、その交換によってシャンク長さを変更でき、もって基端部側のドライバ部１６を有するシャンク軸部材９Ａを交換することなく、適用する削孔深さに応じた適正なシャンク長さを設定できると共に、このシャンク軸部材９の損耗、折損、変形等を生じた際には、該シャンク軸部材９のみを交換して継続使用できる。
【００２０】
また請求項４に係る発明は、前記シャンク軸部材９の両側のねじ結合部１０の一方が雄ねじ５ｄ、他方が雌ねじ５ｂを構成すると共に、このシャンク軸部材９と切削ヘッド４とのねじ結合部１３が、当該シャンク軸部材９相互のねじ結合部１０と同一寸法形状に設定されてなる請求項１〜３の何れかに記載の構成からなるもである。
【００２１】
請求項４に係る発明によれば、必要に応じて複数本のシャンク軸部材９をねじ結合部１０において結合したり、シャンク軸部材９に切削ヘッド４をねじ結合部１３において結合して所用の切削加工を施すことが可能となる。
【００２２】
また請求項５に係る発明は、上記ねじ結合部１０，１３に用いるねじは角ねじであり、かつ該角ねじにおける雄ねじ５ｄの末端側と雌ねじ５ｂの開口端側の不完全ねじ部１３ａを上記クーラントの排出用の溝１（１Ａ，１Ｂ，１Ｃ）の形成範囲内に入って存在しない状態である請求項１〜４の何れかに記載の構成からなるものである。
【００２３】
請求項５に係る発明によれば、シャンク軸部材９相互あるいはシャンク軸部材９と切削ヘッド４との各ねじ係合部１０，１３を角ねじとすれば、結合強度が大きくなると共に、隙間を生じにくいためにねじ係合部１０，１３からのクーラントの漏れを防止できる。
【００２４】
また、シャンク軸部材９相互或いはシャンク軸部材９と切削ヘッドとの各ねじ係合部１０，１３における雄ねじ５ｄの末端側と雌ねじ５ｂの開口端側の不完全ねじ部１３ａが、前記排出溝１（１Ａ，１Ｂ，１Ｃ）の形成範囲内に入って存在しない状態となっているため、排出溝１（１Ａ，１Ｂ，１Ｃ）を形成する切除端面に完全な端面形状のねじ端が臨んで隙間を生じないので、隙間に切屑が引っ掛かって円滑に排出できないというような不具合の発生を防止できる。
【００２５】
また請求項６に係る発明は、前記シャンク軸３の外周のクーラントの排出溝１は、軸に直交する方向の切断面の深さＬ１はシャンク軸半径の１／２乃至１／４の割合であり、周方向には全周の略１／３〜１／５の長さＬ２の割合に形成されてなる請求項１〜５の何れかに記載の構成からなるもである。
【００２６】
請求項６に係る発明によれば、クーラントの排出溝１は、シャンク軸３の外周壁の一部が切除された部分６に形成されるものであるが、その部分の径方向の深さ、即ちシャンク軸３の外周壁を切除した切除端面８ｂ，８ｃの深さＬ１とシャンク軸３の周方向の外周壁の切除量Ｌ２を上記の範囲内に自在に設定することができ、これによってクーラントの排出能力、従って、被加工物Ｗの切削孔Ｈ内で発生した切屑Ｓの排出能力を自在に調整することができる。
【００２７】
また請求項７に係る発明は、切削ヘッド４には、シャンク軸３側のクーラントの供給通路２側に連通して単数又は複数のクーラントの吐出口１５が設けられてなる請求項１〜６の何れかに記載の構成からなるものである。
【００２８】
切削ヘッド４には切刃である超硬チップが取り付けられるようになっているため、そのヘッド本体４ａには中心部から略９０°の断面Ｖ字状の開口部が形成されなければならず、これがために、他の部分に形成するようなの前述の切除部８からなる供給通路２を形成することができない。これがために、この発明にあっては、シャンク軸３側のクーラントの供給通路２側に連通して単数又は複数のクーラントの吐出口１５が設けられてなるため、ヘッド本体４ａにはその中心部から略９０°の断面Ｖ字状の開口部を形成することができ、なおかつ切屑やクーラントの排出能力を妨げることはない。
【００２９】
【発明の実施の形態】
以下に本発明に係る深孔切削具の好適実施形態について、図面を参照して具体的に説明する。
【００３０】
本発明の一実施形態であるガンドリルは、図１（Ａ）〜（Ｃ）に示すように、ドライバ部１６を備えた基部シャンク軸部材９Ａと、その先端に一端側をねじ結合部１０でねじ結合して同軸状に着脱可能に連結された中間部シャンク軸部材９Ｂと、この中間部シャンク軸部材９の他端側にヘッド部シャンク軸部材９Ｃを同じくねじ結合部１３でねじ結合して同軸状に着脱可能に連結されたドリリング用の切削ヘッドであるドリルヘッド４とで構成されている。なお、図１（Ａ）のＢで囲んだ部分は、図１（Ｂ）に、またＣで囲んだ部分は、図１（Ｃ）に拡大して示す。
【００３１】
基端部側のシャンク軸部材９Ａは、図２（Ａ）〜（Ｃ）で詳細に示すように、シャンク軸３に同心に略軸方向全域に貫通孔７が設けられて該貫通孔７がクーラントの供給通路２を形成し、シャンク軸３の外周壁の一部が前記貫通孔７を避けて略軸方向全域に直線状に切除されて該切除部８が上記クーラントの排出溝１Ａを形成してなる。
【００３２】
シャンク軸部材９Ａを、長尺な中実丸軸部材を用いて形成する場合に、例えば１．５メートルを超える中実丸軸部材の中心部に孔明け作業を行う場合に、孔明け作業具と中実丸軸部材を相対回転させながら孔明け作業を行うことができるから、直進性の良好なシャンク軸部材９Ａを容易に製作することができる。なお、シャンク軸部材９Ａの基端部には回転駆動力を受ける太径のドライバ部１６が同軸状に切削加工によって一体形成されている。
【００３３】
また、図２の（Ｂ），（Ｃ）に示すように、シャンク軸部材９Ａの外周壁の一部が貫通孔７を避けて略軸方向に切除されて切除部８を形成することによって切除部８の底面には貫通孔７の外周面の一部が露出することになり、この貫通孔７の露出した外周面８ａと前記切除部の切除端面８ｂ，８ｃとに囲繞されて切除部８が形成され、該切除部８がクーラントの排出溝１Ａを形成することになる。
【００３４】
基部シャンク軸部材９Ａの基部側には、図２の（Ａ）に示すように、基端側の大径なドライバ部１６の付近まで切除部８であるクーラント排出溝１Ａが長手方向に沿って形成されると共に、基部シャンク部材９Ａの先端側には接続筒部５ａが設けてあり、この接続筒部５ａの内奥側に角ねじにて構成される雌ねじ５ｂが刻設されている。しかして、排出溝１Ａは、図２（Ｂ），（Ｃ）に示すように、基部シャンク軸部材９Ａの外周側に形成される切除部８は、シャンク軸９Ａのシャンク軸心Ｏを中心として略９０°の開きをなす周方向長さＬ２で該切除端面５ｅ，５ｆの厚み幅Ｌ１分が欠いた形になっており、接続筒部５ａ及び雌ねじ５ｂでは周壁５ａ１を切り欠いて切除部８が形成される。また、ドライバ部１６には基端から中間位置に達する中心孔１６ａが形成され、この中心孔１０ａの内底から基部シャンク軸部材９Ａの接続筒部５ａの雌ねじ５ｂの直前に至る貫通孔６であるクーラント供給通路２が形成されている。
【００３５】
上述のように、排出溝１Ａである切除部８は、図２（Ｂ），（Ｃ）に示すように、基部シャンク軸部材９Ａの外周側に形成される切除部８は、シャンク軸心Ｏを中心として略９０°の開きをなす周方向長さＬ２で該切除端面５ｅ，５ｆの厚み幅Ｌ１分が欠いて形成されるため、排出溝１Ａの排出断面積は、上記周方向長さＬ２と厚み幅Ｌ１との割合で決定されることになり、前記貫通孔７の内径が一定であれば、上記周方向長さＬ２によって排出溝１Ａの排出断面積、従ってクーラントの排出能力が決定されることになる。
【００３６】
中間部シャンク部材９Ｂは、前述の基部シャンク部材９Ａと同一外径の丸筒状であり、図３（Ａ）〜（Ｃ）で詳細に示すように、シャンク軸３に同心に略軸方向全域に貫通孔７が設けられて該貫通孔７がクーラントの供給通路２を形成し、シャンク軸３の外周壁の一部が前記貫通孔７を避けて略軸方向全域に直線状に切除されて該切除部８が上記クーラントの排出溝１Ｂを形成してなる。
【００３７】
そして、中間部シャンク部材９Ｂの一端側には前述の基部シャンク部材９Ａ、に形成した接続筒部５ａ内に密に嵌入し得る外径の接続軸部５ｃを有し、この接続軸部５ｃの先端側に前記接続筒部５ａの雌ねじ５ｄに螺合する角ねじからなる雄ねじ５ｄが刻設されると共に、他端側には基部シャンク軸部材９Ａの接続筒部５ａと同一寸法形状で内奥に角ねじからなる雌ねじ５ｂを刻設した接続筒部５ａが形成されている。そしてシャンク軸３に形成した貫通孔６であるクーランク供給通路２は、その一端部が雌ねじ５ｂの直前に至り、他端部が雄ねじ５ｄの先端面に至るまで設けられている。
【００３８】
しかして、排出溝１Ｂは、図３（Ｂ），（Ｃ）に示すように、中間部シャンク軸部材９Ｂの外周側に形成される切除部８は、シャンク軸心Ｏを中心として略９０°の開きをなす周方向長さＬ２で該切除端面５ｅ，５ｆの厚み幅Ｌ１分が欠いた形になっており、他端部の接続筒部５ａ及び雌ねじ５ｂでは周壁５ａ１を切り欠いて切除部８が形成され、一端部の接続軸部５ｃ及び雄ねじ５ｄでも周壁５ｃ１を切り欠いて切除部８が形成される。
【００３９】
しかして、基部シャンク軸部材９Ａと中間部シャンク軸部材９Ｂとは、図１（Ａ），（Ｃ）に示すように、両者の連結状態、つまり基部シャンク部材９Ａの外周側に形成した接続筒部５ａに中間部シャンク軸部材９Ｂの外周側に形成した接続軸部５ｃを一杯に嵌入螺合して、接続軸部５ｃの基部側の段部５ｇが接続筒部５ａの端面に密接した状態で、両者の排出溝１Ａ，１Ｂ同士がずれなく直線的に連なると共に、基部側シャンク部材９Ａに形成した貫通孔６であるクーラント供給通路２と中間部シャンク軸部材９Ｂに形成した貫通孔６であるクーラント供給孔２とが連通するように設定されており、これによってシャンク軸３が形成されることになる。
【００４０】
ドリルヘッド４は、図４（Ａ）〜（Ｄ）で詳細に示すように、基端側にヘッド部シャンク軸部材９Ｃが形成され、該軸部材９Ｃに接続軸部５ｃが形成され、この接続軸部５ｃの先端側に前記中間部シャンク部材９Ｂ側の前記接続筒部５ａの雌ねじ５ｂに螺合する角ねじからなる雄ねじ５ｄが刻設されると共に、ヘッド部シャンク軸部材９Ｃに形成した貫通孔７であるクーランク供給通路２は、その一端部が後述のドリル本体４ｂの端面に至り、他端部は雄ねじ５ｄの先端面に至るまで設けられている。また、排出溝１Ｃは、図４（Ｃ）、（Ｄ）に示すように、ヘッド部シャンク軸部材９Ｃの軸心Ｏを中心として切除して形成され、これがために接続軸部５ｃ及び雄ねじ５ｄはその一部周壁５ｃ１が切除されることは前記中間部シャンク軸部材９Ｂと同じである。
【００４１】
そして、ドリルヘッド４の切刃側のヘッド本体４ｂは中実となっており、この中実ヘッド本体４ｂに前記ヘッド部シャンク軸部材９Ｃに形成した切除部８である排出溝１Ｃに隣接するヘッド本体４ｂには、切刃を形成する超硬チップ１７を取り付ける必要があるため、軸心を中心として約９０°に開いた断面Ｖ字状の排出溝４ｃが形成され、この排出溝４ｃの一側に臨むように超硬チップ１７がロー付けなどによって取り付けられる一方、中実ヘッド本体４ｂには接続軸部５ｃの端面、正確にはヘッド部シャンク軸部材９Ｃに形成した貫通孔７である供給通路２に連通して当該ヘッド本体４ｂの先端面４ｄに至る２本のクーラント供給孔６ｃ，６ｃが穿設され、当該先端面４ｄに両クーラント供給孔６ｃ，６ｃの開口部である吐出口１５，１５が開いている。また、排出溝４ｃを外れた外周部の二箇所にガイドパッド１８が固着されている。
【００４２】
しかして、このドリルヘッド４は、図１（Ａ），（Ｂ）に示すように、そのヘッド部シャンク部材９Ｃに形成した接続軸部５ｃを中間部シャンク軸部材９Ｂの接続筒部５ａに一杯に嵌入螺合して、接続筒部５ａの端面が接続軸部５ｃの基部側の段部５ｇ密接した状態で、排出溝４ｃおよび１Ｃが中間部シャンク軸部材９Ｂの排出溝１Ｂにずれなく直線的に連なると共に、ドリルヘッド４側のクーラント供給通路２が中間部シャンク軸部材９Ｂのクーラント供給孔２に連通するように設定されている。なお、ドリルヘッド４の接続軸部５ｃと中間部シャンク軸部材９Ｂの接続軸部５ｃとは同一寸法形状になっている。
【００４３】
基部側シャンク部材９Ａ及び中間部シャンク軸部材９Ｂの接続筒部５ａ，５ａ（図２（Ａ），図３（Ａ））における雌ねじ５ｂ，５ｂの末端側と、中間部シャンク軸部材９Ｂ及びドリルヘッド４のヘッド部シャンク軸部材９Ｃの接続軸部５ｃ，５ｃ（図２（Ａ），図３（Ａ））における雄ねじ５ｄ，５ｄの開口端側においては、図４（Ｃ）におけるドリルヘッド４のヘッド部シャンク軸部材９Ｃと中間部シャンク軸部材９Ｂとのねじ結合部１３（図１（Ｂ）参照）で代表して示すように、雌雄ねじ５ａ，５ｄの不完全ねじ部１３ａを排出溝１（１Ｃ）の形成範囲に収め、これら排出溝１（１Ｃ）の両側面で完全なねじ断面形状でねじ端が終了し、排出溝１に臨むねじ端で隙間が生じないようになっている。
【００４４】
なお、中間部シャンク軸部材９Ｂ及びヘッド部シャンク軸部材９Ｃの接続軸部５ｃ，５ｃ、ならびにこれらに各々対応する中間部シャンク軸部材９Ｂ及び基部シャンク軸部材９Ａの接続筒部５ａ，５ａとは、同一長さで且つ略同じ内外径のパイロット部として、接続筒部５ａ，５ａに接続軸部５ｃ，５ｃが円滑に嵌入して正確に同芯状態に螺合できるように構成されている。
【００４５】
このようなガンドリルにあっては、シャンク軸３として通常１５０〜５００ｍｍ程度の長さのものが使用されるが、このような範囲で長さの異なる複数本の中間部シャンク軸部材９Ａ…を用意しておく。また、上記実施形態では切削ヘッドとしてドリルヘッド４を例示したが、例えばミリングヘッド等の他の切削作業に用いる切削ヘッドとしても、ドリルヘッド４と同様に基端側にヘッド部シャンク部材９Ｃを形成して、これに雄ねじ５ｄを有する接続軸部５ｃと、外周面に全長に排出溝４ｃ，１Ｃを設けたものを用意することが推奨される。
【００４６】
このガンドリルにあっては、まず、シャンク軸３に同心に略軸方向全域に貫通孔７が設けられて、該貫通孔７を利用して、これをクーラントの供給通路２としたため、該供給通路の製作が容易である。なお、このシャンク軸３は、後述のように複数のシャンク軸部材９が互いにねじ結合されて形成される場合以外に、長尺の一本のシャンク軸からなる場合にも適用されることは勿論である。
【００４７】
製作上において、中実丸軸部材の中心部を穿孔して貫通孔７を形成する場合にあっても、中実丸軸部材の同心（軸心）に貫通孔７を形成する際に、従来のように偏心位置に孔明けするものであるから、中実丸軸部材と孔明け工具との相対回転によって孔明け作業を行うことが可能であり、このため中実丸軸部材が１．５メートルを超える長尺部材であっても直進性の優れたクーラント供給通路である貫通孔を形成することができ、精度良好な深孔切削具を容易に製作することができる。
【００４８】
更に、シャンク軸３に同心に貫通孔７を形成し、この貫通孔７をクーラント供給通路２となすため、クーラント供給通路２を大径に形成することが可能となり、それだけクーラントの供給能力を向上させることができる。このように、クーラント供給通路２を大径に形成しても、後述のようにシャンク軸３が外周壁を一部切除して形成されるクーラント排出溝１の断面積を出来るだけ小さくとることによって、軸強度を必要充分に確保することができる。
【００４９】
そして、シャンク軸３の外周壁の一部を前記貫通孔７を避けて、即ち貫通孔７に連通しないようにして略軸方向全域を切除して、この切除部８をクーラント及び切屑の排出溝１となしたため、製作上からはシャンク軸３の一部を軸方向に切削するだけでよいからその製作が容易である。
【００５０】
そしてまた、シャンク軸３の外周壁の一部を前記貫通孔７を避けて切除することによって、該切除部８の底部には貫通孔７の外周面８ａの一部が露出することになり、従って、該切除部８は前記貫通孔７の露出した外周面８ａとシャンク軸３の一部を切除した切除端面８ｂ，８ｃとに囲繞された空隙部によって形成され、該切除部８は大径に形成された貫通孔７の外側に形成されるため、従来のシャンク軸の軸心を通る断面Ｖ字状のクーラント排出溝の断面積にくらべて、その断面積が小さくなるが、上述のようにクーラントの供給通路２のクーラント供給能力が向上することと相まって、クーラントの排出溝の断面積が多少小さくなっても、むしろクーラントの流速が速くなり、切屑の排出能力を格段に向上させことができる。
【００５１】
また本実施形態のガンドリルによれば、シャンク軸３が基部側シャンク部材９Ａと独立部材である中間部シャンク軸部材９Ｂとから構成されているから、シャンク軸部材９Ｂとして長さの異なるものを交換することによってシャンク長さを変更でき、もって同じ基部シャンク軸部材９Ａを用いて適用する削孔深さに応じた適正なシャンク長さに設定することが可能となる。従って、従来のようにシャンク長さが数段階に異なる複数種の深孔切削具を用意する場合に比較して、備品コストが大幅に低減される。また、経時的なシャンク側の損耗、ならびに使用中におけるシャンク側の突発的な折損や変形の殆どは、切削負荷による捩れ応力が集中し易いシャンク軸中間部で生起するが、本発明の実施形態のガンドリルでは、該捩れ応力の集中部分が概して中間部シャンク軸部材９Ｂになるため、傷んだ中間部シャンク軸部材９Ｂのみを新品と交換することにより、傷みにくいが構造的及びサイズ的に製作コストの高い基部シャンク部材９Ａを長期にわたって継続使用でき、これによって保全コストも大きく低減できる。
【００５２】
更に、本実施形態のガンドリルにあっては、中間部シャンク軸部材９Ｂの一端側が雄ねじ５ｄを有する接続軸部５ｃ、他端側が雌ねじ５ｂを有する接続筒部５ａを構成し、基部側シャンク部材９Ａと中間部シャンク軸部材９Ｂの接続筒部５ａ，５ａ、ならびに中間部シャンク軸部材９Ｂとドリルヘッド４のヘッド部シャンク部材９Ｃの接続軸部５ｃ，５ｃが同一寸法形状に設定されているから、複数本の中間部シャンク軸部材９Ｂ…を直線状に連結したり、中間部シャンク軸部材９Ｂを介さずに基部にドライバ部１６を備えた長尺な一本のシャンク軸３に対してドリルヘッド４を直接に連結することも可能であり、複数本の中間部シャンク軸部材９Ｂ…の連結によって極端に長い削孔にも対応できる一方、逆に一本の長尺なシャンク軸３へのドリルヘッド４の直接連結によって比較的に短い削孔にも対応できる。
【００５３】
一方、ドリルヘッド４の切刃である超硬チップ１７の消耗や折損を生じた際は、該ドリルヘッド４のみを取り替えるだけでよく、基部シャンク軸部材９Ａ及び中間部シャンク軸部材９Ｂをそのまま継続使用でき、段取り替えに際しても該ドリルヘッド４のみをねじ込み交換するだけでよいため、簡単に短時間で作業を行えて生産効率が向上し、また、ドリリングとリーミングのように他の切削作業に切り換える場合にも、対応する種類の切削ヘッドだけを用意しておけばよいので、備品コストを低減できると共に交換作業も短時間で容易に行える。
【００５４】
また、本実施形態では、中間部シャンク軸部材９Ｂと基部シャンク部材９Ａ及びドリルヘッド４のヘッド部シャンク部材９Ｃとの各ねじ結合部における雌ねじ５ｂ及び雄ねじ５ｄを角ねじにて構成しているので、高い結合強度が得られると共に、ねじ部に隙間が生じ難いため、ねじ結合部からのクーラントの漏れが防止される。
【００５５】
また、各ねじ係合部における雄ねじ５ｄの末端側と雌ねじ５ｂの開口端側の不完全ねじ部が、図４の（Ｃ）に示すように、前記排出溝１（１Ａ，１Ｂ，１Ｃ）の形成範囲内に収まっているため、これら排出溝の両側面に完全な断面形状のねじ端が臨んで隙間を生じないから、隙間に切屑が引っ掛かって円滑に排出できないといった不具合も防止される。
【００５６】
なお、上記実施形態では、基部シャンク軸部材９Ａ及び中間部シャンク軸部材９Ｂの一端部を接続筒部５ａ及び雌ねじ５ｂとし、中間部シャンク軸部材９Ｂの他端部を接続軸部５ｃ及び雄ねじ５ｄとし、ヘッド部シャンク軸部材９Ｃの一端部を接続軸部５ｃ及び雄ねじ５ｄとしているが、これとは反対に基部シャンク軸部材９Ａ及び中間部シャンク軸部材９Ｂの一端部を接続軸部５ｃ及び雄ねじ５ｄとし、中間部シャンク軸部材９Ｂの他端部を接続筒部５ａ及び雌ねじ５ｂとし、ヘッド部シャンク軸部材９Ｃの一端部を接続筒部５ａ及び雌ねじ５ｂとし、これによってねじ結合部１０，１３を形成するようにしてもよい。また、実施形態の説明ではドリルヘッド４に切刃を形成する超硬チップ１７をロウ付けした例を示したが、ドリルヘッド４の如き切削ヘッド全体を工具鋼にて構成し、その先端に切刃を直接形成したり、前記超硬チップ８をドリルヘッド３にねじ止めしたりする構成も採用可能である。更に、各部材９Ａ，９Ｂ，９Ｃの排出溝１（１Ａ，１ｂ，１Ｃ）の周方向長さＬ２は、Ｖ字状断面の開き角が９０°のものを例示したが、略９０°〜１３０°の範囲の適当な開き角に設定することもできる。
【００５７】
【発明の効果】
請求項１に係る発明によれば、まず、シャンク軸に同心に略軸方向全域に貫通孔が設けられて、該貫通孔を利用して、これをクーラントの供給通路としたため、該供給通路の製作が容易である。なお、このシャンク軸は、後述のように複数のシャンク軸部材が互いにねじ結合されて形成される場合以外に、長尺の一本のシャンク軸からなる場合にも適用されることは勿論である。
【００５８】
製作上において、中実丸軸部材の中心部を穿孔して貫通孔を形成する場合にあっても、中実丸軸部材の同心（軸心）に貫通孔を形成する際に、中実丸軸部材と孔明け工具との相対回転によって孔明け作業を行うことが可能であり、このため中実丸軸部材が１．５メートルを超える長尺部材であっても直進性の優れたクーラント供給通路である貫通孔を形成することができ、精度良好な深孔切削具を容易に製作することができる。
【００５９】
更に、シャンク軸に同心に貫通孔を形成し、この貫通孔をクーラント供給通路となすため、クーラント供給通路を大径に形成することが可能となり、それだけクーラントの供給能力を向上させることができる。このように、クーラント供給通路を大径に形成しても、後述のようにシャンク軸が外周壁を一部切除して形成されるクーラント排出溝の断面積を出来るだけ小さくとることによって、軸強度を必要充分に確保することができる。
【００６０】
そして、シャンク軸の外周壁の一部を前記貫通孔を避けて、即ち貫通孔に連通しないようにして略軸方向全域を切除して、この切除部をクーラント及び切屑の排出溝となしたため、製作上からはシャンク軸の一部を軸方向に切削するだけでよいからその製作が容易である。
【００６１】
そしてまた、シャンク軸の外周壁の一部を前記貫通孔を避けて切除することによって、該切除部の底部には貫通孔の外周面の一部が露出する形とになり、従って、該切除部は前記貫通孔の露出した外周面とシャンク軸の一部を切除した切除端面とに囲繞された空隙部によって形成され、該切除部は大径に形成された貫通孔の外側に形成されるため、従来のシャンク軸の軸心を通る断面Ｖ字状のクーラント排出溝の断面積にくらべて、その断面積が小さくなるが、上述のようにクーラントの供給通路のクーラント供給能力が向上することと相まって、クーラントの排出溝の断面積が多少小さくなっても、むしろクーラントの流速が速くなり、切屑の排出能力が格段に向上させことができる。
【００６２】
請求項２に係る発明によれば、切削ヘッドがシャンク軸から着脱可能に設けられることによって、切削ヘッドあるいはシャンク軸の摩耗や欠損等で何れか一方を取り替える必要がある場合に、従来の切削ヘッドとシャンク軸との一体のものに比べて、摩耗や欠損した上記部品のみを交換すればよいからそれだけ修理費用が安価につく。
【００６３】
更にはドリリングとリーミングのように他の切削作業に切り換えたりする場合には、この切削ヘッドのみを交換するだけで、ドリリング作業からリーミング作業に容易に転換することができ、一方シャンク軸は継続使用することができる。
【００６４】
このように切削ヘッド４がシャンク軸３がねじ結合によって連結されるようになっているため、両者の連結構造が簡単で安価に製作することが可能であり、且つ摩耗や欠損時の何れか一方の部品の交換作業を容易に行うことができる。
【００６５】
請求項３に係る発明によれば、シャンク軸が複数の互いにねじ結合された複数のシャンク軸部材からなるため、各シャンク軸部材として長さの異なる複数本を用意しておけば、その交換によってシャンク長さを変更でき、もって基端部側のドライバ部を有するシャンク軸部材を交換することなく、適用する削孔深さに応じた適正なシャンク長さを設定できると共に、このシャンク軸部材の損耗、折損、変形等を生じた際には、該シャンク軸部材のみを交換して継続使用できる。
【００６６】
請求項４に係る発明によれば、必要に応じて複数本のシャンク軸部材を連結したり、シャンク軸部材に切削ヘッドを連結して所用の切削加工を施すことが可能となる。
【００６７】
請求項５に係る発明によれば、シャンク軸部材相互あるいはシャンク軸部材と切削ヘッドとの各ねじ係合部を角ねじとすれば、結合強度が大きくなると共に、隙間を生じにくいためにねじ係合部からのクーラントの漏れを防止できる。
【００６８】
また、シャンク軸部材相互或いはシャンク軸部材と切削ヘッドとの各ねじ係合部における雄ねじの末端側と雌ねじの開口端側の不完全ねじ部が、前記排出溝の形成範囲内に入って存在しない状態となっているため、排出溝を形成する切除端面に完全な端面形状のねじ端が臨んで隙間を生じないので、隙間に切屑が引っ掛かって円滑に排出できないというような不具合の発生を防止できる。
【００６９】
請求項６に係る発明によれば、クーラントの排出溝は、シャンク軸の外周壁の一部が切除された部分に形成されるものであるが、その部分の径方向の深さ、即ちシャンク軸の外周壁を切除した切除端面の深さとシャンク軸の周方向の外周壁の切除量を上記の範囲内に自在に設定することができ、これによってクーラントの排出能力、従って、被加工物の切削孔内で発生した切屑の排出能力を自在に調整することができる。
【００７０】
請求項７に係る発明によれば、切削ヘッドには切刃である超硬チップが取り付けられるようになっているため、そのヘッド本体には中心部から略９０°の断面Ｖ字状の開口部が形成されなければならず、これがために、他の部分に形成するようなの前述の切除部からなる供給通路を形成することができない。これがために、この発明にあっては、シャンク軸側のクーラントの供給通路側に連通して単数又は複数のクーラントの吐出口が設けられてなるため、ヘッド本体にはその中心部から略９０°の断面Ｖ字状の開口部を形成することができ、なおかつ切屑やクーラントの排出能力を妨げることはない。
【図面の簡単な説明】
【図１】本発明の一実施形態であるガンドリルを示し、（Ａ）は全体構成を示す部分省略正面図、（Ｂ）は（Ａ）の仮想線円Ｂ内の拡大図、（Ｃ）は（Ａ）の仮想線円Ｃ内の拡大図である。
【図２】同実施形態のガンドリルに用いる基部シャンク軸部材を示し、（Ａ）は全体構成を示す部分省略正面図、（Ｂ）は先端から見た側面図、（Ｃ）は（Ａ）のＣ−Ｃ線の矢視断面図である。
【図３】同実施形態のガンドリルに用いる中間部シャンク軸部材を示し、（Ａ）は全体構成を示す部分省略正面図、（Ｂ）は先端から見た側面図、（Ｃ）は（Ａ）のＣ−Ｃ線の矢視断面図である。
【図４】同実施形態のガンドリルに用いる切削ヘッドを示し、（Ａ）は全体構成を示す部分省略正面図、（Ｂ）は先端から見た側面図、（Ｃ）は（Ａ）のＣ−Ｃ線の断面図、（Ｄ）は基端から見た側面図である。
【図５】本発明の他の実施形態を示すガンドリルの正面図である。
【図６】（ａ）および（ｂ）は、従来から使用されているガンドリルシステムの概略構成とそれに用いるガンドリルの断面図である。
【符号の説明】
１クーラントの排出溝
２クーラントの供給通路
３シャンク軸
４切削ヘッド
７貫通孔
８切除部
９シャンク軸部材
９Ａ基部シャンク軸部材
９Ｂ中間部シャンク軸部材
９Ｃヘッド部シャンク軸部材
１０ねじ結合部
５ｄ雄ねじ
５ｂ雌ねじ
１３ねじ結合部
１３ａ不完全ねじ部
１５吐出口
１６ドライバ部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a deep hole cutting tool such as a drill and a reamer applied to a gun drill system.
[0002]
[Prior art]
As a deep hole drilling system, a gun drill system, a BTA system, an ejector system, and the like are known, but a gun drill system having a simple configuration is widely used for deep hole drilling of a relatively small diameter.
[0003]
As a gun drill system, for example, conventional techniques described in Patent Literature 1 or 2 can be generally mentioned. This structure will be described with reference to FIG. 6A. A drill head 32 is integrally fixed to the tip of a shank shaft 31 having a hollow cylindrical shape and having a V-shaped concave groove 34 formed along the longitudinal direction on the outer surface thereof. Using a gun drill 30 in which a hollow portion of the shank shaft 31 is a supply passage 33 for the coolant C and a concave groove is a discharge groove 34 for the chips S, a high-pressure coolant C is supplied through the supply passage 33 to the drill head 32 during deep hole drilling. The chip S is discharged from the front end side, and the chips S generated in the cutting holes H of the workpiece W are discharged to the outside through the discharge grooves 34 together with the coolant C.
[0004]
[Patent Document 1]
Japanese Patent Publication No. 59-12405 [Patent Document 2]
Japanese Utility Model Publication No. 60-53416 [0005]
As a gun drill used in the above-mentioned gun drill system, as shown in the sectional view of FIG. 1B, supply passages 33a and 33b for the coolant C are formed in the hollow portion of the shank shaft 31, and the shank shaft 31 is cut off. The coolant discharge groove 34 is formed by cutting out substantially the entire area in the axial direction so that the cross section has a V-shape of approximately 90 degrees about the shank axis O as a center. Thus, the discharge of the coolant discharge groove 34 is performed. The area is large and the coolant discharge capacity is provided with a margin. On the other hand, the cross-sectional area of the supply passages 33a and 33b for the coolant C formed near the axis of the shank shaft 31 cannot be made too large for reasons of strength. Even if the discharge capacity is increased, the supply capacity of the coolant C is limited. Therefore, after all, the chips S generated in the cutting hole H of the workpiece W are discharged through the discharge groove 34 together with the coolant C. There was a certain limit on the discharge capacity to discharge.
[0006]
Further, as described above, approximately one-fourth of the cross-sectional area of the shank shaft 31 is cut off around its axis O to increase the cross-sectional area of the coolant discharge groove 34. The coolant supply passages 33a, 33b formed in the vicinity of the axis of the shaft 31 have to be single or plural small-diameter through passages 33a, 33b avoiding the axis O of the shank shaft 31 as shown in the figure. For this reason, if the length of the shank shaft 31 exceeds 1.5 meters, it is difficult to maintain the straightness of the through passages 33a and 33b in drilling, and there is a problem in the production thereof.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and by devising the formation of a coolant supply passage and a coolant discharge groove or the structure of a shank shaft, it is possible to ensure sufficient strength of the shank shaft and achieve high precision. It is an object of the present invention to secure ease of manufacture and to improve the ability of chips to be discharged by coolant.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is provided with a reference numeral shown in the embodiment, and a coolant discharge groove 1 is provided in an outer peripheral portion, and a coolant supply passage 2 is provided in the inside. 1. A deep hole cutting tool provided with a shank shaft 3 provided and a cutting head 4 at a tip end of the shank shaft 3, wherein a through hole 7 is provided concentrically with the shank shaft 3 in substantially the entire axial direction. 7 forms the coolant supply passage 2, and a part of the outer peripheral wall of the shank shaft 3 is cut linearly in substantially the entire axial direction avoiding the through hole 7, and the cut portion 8 is formed as the coolant discharge groove. 1 is formed.
[0009]
According to the first aspect of the present invention, first, the through hole 7 is provided concentrically with the shank shaft 3 in substantially the entire axial direction, and the through hole 7 is used as the coolant supply passage 2. The supply passage is easy to manufacture. The shank shaft 3 is of course applicable not only to the case where a plurality of shank shaft members 9 are formed by screw connection to each other as described later, but also to the case where the shank shaft 9 is formed of a single long shank shaft. It is.
[0010]
In manufacturing, even when the center portion of the solid round shaft member is pierced to form the through hole 7, when forming the through hole 7 concentrically (axially) of the solid round shaft member, Drilling work can be performed by the relative rotation of the solid round shaft member and the drilling tool, and therefore, even if the solid round shaft member is a long member exceeding 1.5 meters, excellent straightness can be obtained. A through hole serving as a coolant supply passage can be formed, and a high-precision deep hole cutting tool can be easily manufactured.
[0011]
Further, since the through hole 7 is formed concentrically with the shank shaft 3 and the through hole 7 is used as the coolant supply passage 2, the coolant supply passage 2 can be formed to have a large diameter, thereby improving the coolant supply capability. Can be done. Thus, even if the coolant supply passage 2 is formed to have a large diameter, the cross-sectional area of the coolant discharge groove 1 formed by partially cutting the outer peripheral wall of the shank shaft 3 as described later is made as small as possible. The required and sufficient axial strength can be secured.
[0012]
Then, a part of the outer peripheral wall of the shank shaft 3 is cut away from the through hole 7, that is, the whole axial direction is cut so as not to communicate with the through hole 7, and the cut portion 8 is formed into a coolant and chip discharge groove. Since the number is set to 1, it is only necessary to cut a part of the shank shaft 3 in the axial direction from the viewpoint of manufacture, so that the manufacture is easy.
[0013]
Further, by cutting a part of the outer peripheral wall of the shank shaft 3 avoiding the through hole 7, a part of the outer peripheral surface 8a of the through hole 7 is exposed at the bottom of the cut part 8, Therefore, the cut portion 8 is formed by a gap surrounded by the exposed outer peripheral surface 5a of the through hole 7 and cut end surfaces 8b and 8c obtained by cutting a part of the shank shaft 3, and the cut portion 8 has a large diameter. Is formed outside the through-hole 7 formed in the coolant passage, the cross-sectional area is smaller than the cross-sectional area of the coolant discharge groove having a V-shaped cross-section passing through the axis of the conventional shank shaft. In addition to the fact that the coolant supply capacity of the coolant supply passage 2 is improved, even if the cross-sectional area of the coolant discharge groove is slightly reduced, the flow rate of the coolant is rather increased, and the chip discharge capacity is significantly improved. it can.
[0014]
According to a second aspect of the present invention, the shank shaft 3 has a configuration according to the first aspect, wherein a cutting head 4 is detachably provided at a tip portion by screw connection.
[0015]
According to the invention according to claim 2, the cutting head 4 is detachably provided from the shank shaft 3, so that when any one of the cutting head 4 and the shank shaft 3 needs to be replaced due to wear or breakage, Compared with the conventional one in which the cutting head and the shank shaft are integrated, only the above-mentioned worn or defective parts need to be replaced, so that the repair cost is correspondingly lower.
[0016]
Further, when switching to another cutting operation such as drilling and reaming, only the cutting head 4 is replaced, and the shank shaft 3 can be continuously used.
[0017]
As described above, since the cutting head 4 is connected to the shank shaft 3 by the screw connection, the connection structure between the two can be manufactured simply and inexpensively. The replacement work of the parts can be easily performed.
[0018]
The invention according to claim 3 has the configuration according to claim 1 or 2, wherein the shank shaft 3 includes a plurality of shank shaft members 9, and the shank shaft members 9 are detachably screwed to each other. Things.
[0019]
According to the invention according to claim 3, since the shank shaft 3 is composed of the plurality of shank shaft members 9 which are screw-connected to each other, if a plurality of shank shaft members 9 having different lengths are prepared, By changing the shank length, the shank length can be changed, and without changing the shank shaft member 9A having the driver portion 16 on the base end side, an appropriate shank length can be set according to the drilling depth to be applied. When the shank shaft member 9 is worn, broken, deformed, or the like, only the shank shaft member 9 can be replaced and used continuously.
[0020]
The invention according to claim 4 is characterized in that one of the threaded joints 10 on both sides of the shank shaft member 9 constitutes a male screw 5d and the other constitutes a female screw 5b, and a threaded joint between the shank shaft member 9 and the cutting head 4. 13 is configured to have the same size and shape as the threaded joints 10 of the shank shaft members 9 to each other.
[0021]
According to the invention according to claim 4, a plurality of shank shaft members 9 are connected at the screw connection portion 10 as needed, or the cutting head 4 is connected to the shank shaft member 9 at the screw connection portion 13 as required. Cutting can be performed.
[0022]
According to a fifth aspect of the present invention, the screws used for the screw connection portions 10 and 13 are square screws, and the incomplete screw portion 13a on the end side of the male screw 5d and the open end side of the female screw 5b in the square screw is connected to the screw. The structure according to any one of claims 1 to 4, wherein the coolant discharge groove 1 (1A, 1B, 1C) does not exist within the formation range.
[0023]
According to the fifth aspect of the present invention, if the screw engaging portions 10 and 13 between the shank shaft members 9 or between the shank shaft members 9 and the cutting head 4 are square screws, the joining strength is increased and the gap is reduced. Since it is unlikely to occur, it is possible to prevent coolant from leaking from the screw engagement portions 10 and 13.
[0024]
In addition, the incomplete screw portion 13a on the end side of the male screw 5d and the open end side of the female screw 5b in each of the screw engaging portions 10 and 13 of the shank shaft member 9 or the shank shaft member 9 and the cutting head is formed by the discharge groove 1 (1A, 1B, 1C) is in a state where it does not exist within the formation range, so that a thread end of a complete end face faces the cut end face forming the discharge groove 1 (1A, 1B, 1C), and a gap is formed. Therefore, it is possible to prevent a problem that chips are caught in the gap and cannot be discharged smoothly.
[0025]
In the invention according to claim 6, in the coolant discharge groove 1 on the outer periphery of the shank shaft 3, the depth L1 of the cut surface in a direction perpendicular to the shaft is 1/2 to 1/4 of the radius of the shank shaft. There is provided a configuration according to any one of claims 1 to 5, which is formed at a ratio of a length L2 of about 1/3 to 1/5 of the entire circumference in the circumferential direction.
[0026]
According to the invention according to claim 6, the coolant discharge groove 1 is formed in the portion 6 from which a part of the outer peripheral wall of the shank shaft 3 is cut off. That is, the depth L1 of the cut end faces 8b and 8c obtained by cutting the outer peripheral wall of the shank shaft 3 and the cut amount L2 of the outer peripheral wall of the shank shaft 3 in the circumferential direction can be freely set within the above-described ranges. , And therefore, the ability to discharge the chips S generated in the cutting holes H of the workpiece W can be freely adjusted.
[0027]
The invention according to claim 7 is characterized in that the cutting head 4 is provided with one or more coolant discharge ports 15 in communication with the coolant supply passage 2 on the shank shaft 3 side. It has a configuration described in any of the above.
[0028]
Since a cutting tip 4 is provided with a carbide tip as a cutting blade, an opening having a V-shaped cross section of approximately 90 ° from the center must be formed in the head main body 4a. For this reason, it is not possible to form the supply passage 2 including the above-described cutout 8 as formed in another portion. For this reason, according to the present invention, one or more coolant discharge ports 15 are provided in communication with the coolant supply passage 2 on the shank shaft 3 side. And an opening having a V-shaped cross section of approximately 90 ° can be formed, and the ability to discharge chips and coolant is not hindered.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the deep hole cutting tool according to the present invention will be specifically described with reference to the drawings.
[0030]
As shown in FIGS. 1A to 1C, a gun drill according to an embodiment of the present invention includes a base shank shaft member 9 </ b> A provided with a driver portion 16, and one end side of which is screwed to a distal end thereof with a screw connection portion 10. An intermediate shank shaft member 9B which is connected and detachably connected coaxially, and a head shank shaft member 9C is similarly screw-connected to the other end side of the intermediate shank shaft member 9 by a screw connection portion 13 to be coaxial. And a drill head 4, which is a cutting head for drilling, detachably connected in a shape. Note that a portion surrounded by B in FIG. 1A is enlarged in FIG. 1B, and a portion surrounded by C is enlarged in FIG. 1C.
[0031]
As shown in detail in FIGS. 2 (A) to 2 (C), a through-hole 7 is provided concentrically with the shank shaft 3 in substantially the entire axial direction of the shank shaft member 9A on the proximal end side. The coolant supply passage 2 is formed, and a part of the outer peripheral wall of the shank shaft 3 is cut linearly in substantially the entire axial direction avoiding the through hole 7, and the cut portion 8 forms the coolant discharge groove 1A. Do it.
[0032]
In the case where the shank shaft member 9A is formed using a long solid round shaft member, for example, when performing a drilling operation at the center of a solid round shaft member exceeding 1.5 meters, a drilling tool is used. Since the drilling operation can be performed while rotating the solid round shaft member and the solid round shaft member relatively, the shank shaft member 9A having good linearity can be easily manufactured. Note that a large-diameter driver section 16 that receives a rotational driving force is coaxially formed integrally with the base end of the shank shaft member 9A by cutting.
[0033]
Further, as shown in FIGS. 2B and 2C, a part of the outer peripheral wall of the shank shaft member 9A is cut substantially in the axial direction so as to avoid the through hole 7, thereby forming a cut portion 8. A part of the outer peripheral surface of the through hole 7 is exposed on the bottom surface of the portion 8, and is surrounded by the exposed outer peripheral surface 8a of the through hole 7 and the cut end surfaces 8b and 8c of the cut portion. Is formed, and the cutout 8 forms the coolant discharge groove 1A.
[0034]
On the base side of the base shank shaft member 9A, as shown in FIG. 2A, a coolant discharge groove 1A, which is a cutout portion 8 up to the vicinity of the large-diameter driver portion 16 on the base end side, extends in the longitudinal direction. At the same time, a connecting cylinder portion 5a is provided at the distal end side of the base shank member 9A, and a female screw 5b formed of a square screw is engraved on the inner side of the connecting cylinder portion 5a. As shown in FIGS. 2B and 2C, the cutout portion 8 formed on the outer peripheral side of the base shank shaft member 9A is formed around the shank axis O of the shank shaft 9A. The cut-out end faces 5e and 5f have a thickness L1 that is cut off by a circumferential length L2 that forms an opening of about 90 °, and the cut-off portion 8 is formed by cutting off the peripheral wall 5a1 in the connection cylinder portion 5a and the female screw 5b. Is formed. The driver 16 has a center hole 16a extending from the base end to an intermediate position. The through hole 6 extends from the inner bottom of the center hole 10a to immediately before the female screw 5b of the connection cylinder 5a of the base shank shaft member 9A. A certain coolant supply passage 2 is formed.
[0035]
As described above, as shown in FIGS. 2B and 2C, the cut portion 8 serving as the discharge groove 1A is formed on the outer peripheral side of the base shank shaft member 9A. The cutout end faces 5e and 5f are formed so as to lack the thickness width L1 at the circumferential length L2 that forms an opening of about 90 ° with respect to the center, and the discharge cross-sectional area of the discharge groove 1A is equal to the circumferential length L2. And the thickness L1. If the inner diameter of the through-hole 7 is constant, the discharge cross-sectional area of the discharge groove 1A, that is, the discharge capacity of the coolant, is determined by the circumferential length L2. Will be.
[0036]
The intermediate shank member 9B has a round cylindrical shape having the same outer diameter as that of the base shank member 9A described above and, as shown in detail in FIGS. The through hole 7 forms the coolant supply passage 2, and a part of the outer peripheral wall of the shank shaft 3 is cut straight in substantially the entire axial direction avoiding the through hole 7. The cutout 8 forms the coolant discharge groove 1B.
[0037]
The intermediate shank member 9B has, at one end thereof, a connecting shaft portion 5c having an outer diameter capable of being tightly fitted in the connecting cylindrical portion 5a formed on the base shank member 9A. A male screw 5d, which is a square screw that is screwed into the female screw 5d of the connection cylinder portion 5a, is engraved on the distal end side, and has the same size and shape as the connection cylinder portion 5a of the base shank shaft member 9A on the other end side. Is formed with a connection cylinder portion 5a in which a female screw 5b made of a square screw is engraved. The cool rank supply passage 2 which is a through hole 6 formed in the shank shaft 3 is provided so that one end thereof reaches immediately before the female screw 5b and the other end thereof reaches the tip end surface of the male screw 5d.
[0038]
As shown in FIGS. 3B and 3C, the cutout 8 formed on the outer peripheral side of the intermediate shank shaft member 9B is substantially 90 ° about the shank axis O. The cut-out end faces 5e and 5f have a thickness L1 that is cut off by a circumferential length L2 that forms an opening, and the cut-out portion is formed by cutting off the peripheral wall 5a1 at the connection cylindrical portion 5a and the female screw 5b at the other end. 8 is formed, and the peripheral wall 5c1 is also cut out with the connecting shaft 5c and the male screw 5d at one end to form the cutout 8.
[0039]
Thus, as shown in FIGS. 1A and 1C, the base shank shaft member 9A and the intermediate shank shaft member 9B are connected to each other, that is, a connecting cylinder formed on the outer peripheral side of the base shank member 9A. The connecting shaft 5c formed on the outer peripheral side of the intermediate shank member 9B is fully fitted and screwed into the portion 5a, and the step 5g on the base side of the connecting shaft 5c is in close contact with the end face of the connecting cylindrical portion 5a. Thus, the two discharge grooves 1A and 1B are linearly connected without displacement, and the coolant supply passage 2 which is the through hole 6 formed in the base side shank member 9A and the through hole 6 formed in the intermediate portion shank shaft member 9B. The coolant supply hole 2 is set so as to communicate with the coolant supply hole 2, thereby forming the shank shaft 3.
[0040]
As shown in detail in FIGS. 4A to 4D, the drill head 4 has a head shank shaft member 9C formed on the base end side, and a connection shaft portion 5c formed on the shaft member 9C. A male screw 5d, which is a square screw that is screwed into the female screw 5b of the connection cylinder part 5a on the intermediate part shank member 9B side, is engraved on the tip end side of the shaft part 5c, and a through hole formed on the head part shank shaft member 9C. One end of the cool rank supply passage 2 which is the hole 7 reaches an end face of a drill body 4b described later, and the other end extends to a tip end face of the male screw 5d. As shown in FIGS. 4 (C) and 4 (D), the discharge groove 1C is formed by cutting off about the axis O of the head shank shaft member 9C, thereby forming the connection shaft portion 5c and the male screw 5d. The part of the peripheral wall 5c1 is cut away in the same manner as the intermediate shank shaft member 9B.
[0041]
The head body 4b on the cutting edge side of the drill head 4 is solid, and the head adjacent to the discharge groove 1C which is the cutout 8 formed in the head shank shaft member 9C is formed on the solid head body 4b. Since it is necessary to attach a carbide tip 17 forming a cutting edge to the main body 4b, a discharge groove 4c having a V-shaped cross section opened at about 90 ° about the axis is formed. The carbide tip 17 is attached by brazing or the like so as to face the side, while the solid head main body 4b is provided with an end face of the connection shaft portion 5c, more precisely, a through hole 7 formed in the head portion shank shaft member 9C. Two coolant supply holes 6c, 6c communicating with the passage 2 and leading to the front end face 4d of the head main body 4b are formed, and the front end face 4d is a discharge port 15 serving as an opening of the two coolant supply holes 6c, 6c. , 1 It is open. Further, guide pads 18 are fixed to two places on the outer peripheral part outside the discharge groove 4c.
[0042]
As shown in FIGS. 1 (A) and 1 (B), the drill head 4 has a connection shaft 5c formed on the head shank 9C and a connection cylinder 5a of the intermediate shank 9B. And the discharge grooves 4c and 1C are linearly aligned with the discharge groove 1B of the intermediate shank shaft member 9B in a state in which the end surface of the connection cylinder 5a is in close contact with the step 5g on the base side of the connection shaft 5c. The coolant supply passage 2 on the drill head 4 side is set so as to communicate with the coolant supply hole 2 of the intermediate shank shaft member 9B. The connection shaft 5c of the drill head 4 and the connection shaft 5c of the intermediate shank shaft member 9B have the same dimensions and shape.
[0043]
The distal ends of the female screws 5b, 5b in the connecting cylindrical portions 5a, 5a (FIGS. 2A and 3A) of the base-side shank member 9A and the intermediate shank shaft member 9B, the intermediate shank shaft member 9B, and the drill At the open end sides of the male screws 5d and 5d in the connection shaft portions 5c and 5c (FIGS. 2A and 3A) of the head shank shaft member 9C of the head 4, the drill head 4 in FIG. As shown by the screw connection portion 13 (see FIG. 1B) of the head shank shaft member 9C and the intermediate shank shaft member 9B, the incomplete screw portion 13a of the female and male screws 5a and 5d is discharged. 1 (1C), the screw ends are finished with a complete screw cross-sectional shape on both side surfaces of the discharge grooves 1 (1C), and no gap is formed at the screw ends facing the discharge grooves 1. .
[0044]
The connecting shaft portions 5c, 5c of the intermediate shank shaft member 9B and the head shank shaft member 9C, and the connecting cylindrical portions 5a, 5a of the intermediate shank shaft member 9B and the base shank shaft member 9A corresponding thereto, respectively. The connecting shaft portions 5c, 5c are smoothly inserted into the connecting cylinder portions 5a, 5a as the pilot portions having the same length and substantially the same inner and outer diameters, so that the connecting shaft portions 5c, 5c can be screwed accurately and concentrically.
[0045]
In such a gun drill, a shank shaft 3 usually having a length of about 150 to 500 mm is used. A plurality of intermediate shank shaft members 9A having different lengths in such a range are prepared. Keep it. In the above embodiment, the drill head 4 is exemplified as the cutting head. However, for example, a head shank member 9C is formed on the base end side similarly to the drill head 4 as a cutting head used for other cutting operations such as a milling head. It is recommended to prepare a connecting shaft portion 5c having an external thread 5d and a discharge groove 4c, 1C provided on the entire outer peripheral surface.
[0046]
In this gun drill, first, a through hole 7 is provided concentrically with the shank shaft 3 in substantially the entire axial direction, and the through hole 7 is used as the coolant supply passage 2. Is easy to manufacture. The shank shaft 3 is of course applicable not only to the case where a plurality of shank shaft members 9 are formed by screw connection to each other as described later, but also to the case where the shank shaft 9 is formed of a single long shank shaft. It is.
[0047]
In manufacturing, even when the center portion of the solid round shaft member is pierced to form the through hole 7, when forming the through hole 7 concentrically (axial) of the solid round shaft member, Since the hole is drilled at the eccentric position as described above, it is possible to perform the drilling operation by the relative rotation of the solid round shaft member and the drilling tool. Even a long member exceeding a meter can form a through hole as a coolant supply passage having excellent straightness, and a highly accurate deep hole cutting tool can be easily manufactured.
[0048]
Further, since the through hole 7 is formed concentrically with the shank shaft 3 and the through hole 7 is used as the coolant supply passage 2, the coolant supply passage 2 can be formed to have a large diameter, thereby improving the coolant supply capability. Can be done. Thus, even if the coolant supply passage 2 is formed to have a large diameter, the cross-sectional area of the coolant discharge groove 1 formed by partially cutting the outer peripheral wall of the shank shaft 3 as described later is made as small as possible. In addition, the shaft strength can be sufficiently and sufficiently secured.
[0049]
Then, a part of the outer peripheral wall of the shank shaft 3 is cut away from the through hole 7, that is, the whole axial direction is cut so as not to communicate with the through hole 7, and the cut portion 8 is formed into a coolant and chip discharge groove. Since the number is set to 1, it is only necessary to cut a part of the shank shaft 3 in the axial direction from the viewpoint of manufacture, so that the manufacture is easy.
[0050]
Further, by cutting a part of the outer peripheral wall of the shank shaft 3 avoiding the through hole 7, a part of the outer peripheral surface 8a of the through hole 7 is exposed at the bottom of the cut part 8, Accordingly, the cut portion 8 is formed by a gap surrounded by the exposed outer peripheral surface 8a of the through hole 7 and cut end surfaces 8b and 8c obtained by cutting a part of the shank shaft 3, and the cut portion 8 has a large diameter. Is formed outside the through-hole 7 formed in the coolant passage, the cross-sectional area is smaller than the cross-sectional area of the coolant discharge groove having a V-shaped cross-section passing through the axis of the conventional shank shaft. In addition to the fact that the coolant supply capacity of the coolant supply passage 2 is improved, even if the cross-sectional area of the coolant discharge groove is slightly reduced, the flow rate of the coolant is rather increased, and the chip discharge capacity is significantly improved. it can.
[0051]
According to the gun drill of the present embodiment, since the shank shaft 3 is composed of the base side shank member 9A and the intermediate shank shaft member 9B which is an independent member, the shank shaft members 9B having different lengths are exchanged. By doing so, the shank length can be changed, and it is possible to set an appropriate shank length according to the drilling depth to be applied using the same base shank shaft member 9A. Therefore, the equipment cost is greatly reduced as compared with the conventional case where a plurality of types of deep hole cutting tools having different shank lengths in several stages are prepared. In addition, most of the shank side wear over time and sudden breakage and deformation of the shank side during use occur in the middle portion of the shank shaft where the torsional stress due to the cutting load tends to concentrate. In the gun drill of the above, since the concentrated portion of the torsional stress generally becomes the intermediate shank shaft member 9B, it is difficult to be damaged by replacing only the damaged intermediate shank shaft member 9B with a new one, but the manufacturing cost is structurally and in size. The base shank member 9A having a high height can be continuously used for a long period of time, and thus the maintenance cost can be greatly reduced.
[0052]
Further, in the gun drill of the present embodiment, one end of the intermediate shank shaft member 9B constitutes a connection shaft portion 5c having a male screw 5d, and the other end constitutes a connection cylinder portion 5a having a female screw 5b. And the connecting cylinder portions 5a and 5a of the intermediate shank shaft member 9B and the connecting shaft portions 5c and 5c of the intermediate shank shaft member 9B and the head shank member 9C of the drill head 4 are set to have the same dimensions and shape. A plurality of intermediate shank shaft members 9B are connected linearly, or a drill head is attached to a single long shank shaft 3 provided with a driver portion 16 at the base without passing through the intermediate shank shaft members 9B. 4 can be directly connected to each other to cope with extremely long drilling by connecting a plurality of intermediate shank shaft members 9B. It can cope with relatively short drilling by direct coupling of Riruheddo 4.
[0053]
On the other hand, when the carbide tip 17 which is the cutting edge of the drill head 4 is worn out or broken, only the drill head 4 needs to be replaced, and the base shank shaft member 9A and the intermediate shank shaft member 9B are continued. Since it can be used and only the screw head 4 needs to be screwed and replaced at the time of setup change, the work can be performed easily and in a short time and the production efficiency is improved, and switching to other cutting work such as drilling and reaming is also possible. Also in this case, only the corresponding type of cutting head needs to be prepared, so that the equipment cost can be reduced and the replacement operation can be easily performed in a short time.
[0054]
Further, in the present embodiment, the female screw 5b and the male screw 5d in each screw connection portion of the intermediate shank shaft member 9B, the base shank member 9A, and the head shank member 9C of the drill head 4 are formed by square screws. As a result, a high coupling strength is obtained, and a gap is hardly formed in the screw portion, so that leakage of the coolant from the screw connection portion is prevented.
[0055]
In addition, as shown in FIG. 4 (C), the incomplete thread portions on the distal end side of the male screw 5d and the open end side of the female screw 5b in each screw engaging portion are formed in the discharge groove 1 (1A, 1B, 1C). Since the screw ends are within the formation range, screw ends having a complete cross-sectional shape face both side surfaces of these discharge grooves, so that no gap is formed. Therefore, a problem that chips are caught in the gap and cannot be discharged smoothly is also prevented.
[0056]
In the above embodiment, one ends of the base shank shaft member 9A and the intermediate shank shaft member 9B are used as the connecting cylinder 5a and the female screw 5b, and the other end of the intermediate shank shaft member 9B is used as the connection shaft 5c and the male screw 5d. One end of the head shank shaft member 9C is connected to the connecting shaft 5c and the male screw 5d. On the contrary, one end of the base shank shaft member 9A and the intermediate shank shaft member 9B is connected to the connecting shaft 5c and the male screw. 5d, the other end of the intermediate shank shaft member 9B is a connection cylinder 5a and a female screw 5b, and one end of the head shank shaft member 9C is a connection cylinder 5a and a female screw 5b. May be formed. Further, in the description of the embodiment, the example in which the carbide tip 17 forming the cutting edge is brazed to the drill head 4 is shown. However, the entire cutting head such as the drill head 4 is made of tool steel, and the tip is cut. It is also possible to adopt a configuration in which a blade is directly formed or the carbide tip 8 is screwed to the drill head 3. Further, the circumferential length L2 of the discharge groove 1 (1A, 1b, 1C) of each member 9A, 9B, 9C is exemplified by a V-shaped cross section having an opening angle of 90 °, but approximately 90 ° to 130 °. It is also possible to set an appropriate opening angle in the range of °.
[0057]
【The invention's effect】
According to the invention of claim 1, first, a through hole is provided substantially in the entire axial direction concentrically with the shank shaft, and the through hole is used as a coolant supply passage. Easy to manufacture. It should be noted that this shank shaft is naturally applied to a case where the shank shaft is formed of a single long shank shaft, in addition to the case where a plurality of shank shaft members are formed by screwing together as described later. .
[0058]
In manufacturing, even when a through hole is formed by piercing the center of a solid round shaft member, when a through hole is formed concentrically (axially) with the solid round shaft member, a solid round shaft member is formed. Drilling work can be performed by the relative rotation of the shaft member and the drilling tool. Therefore, even when the solid round shaft member is a long member exceeding 1.5 meters, the coolant supply excellent in straightness is provided. A through hole serving as a passage can be formed, and a high-precision deep hole cutting tool can be easily manufactured.
[0059]
Furthermore, since a through hole is formed concentrically on the shank shaft and this through hole is used as a coolant supply passage, the coolant supply passage can be formed with a large diameter, and the coolant supply capacity can be improved accordingly. As described above, even if the coolant supply passage is formed to have a large diameter, the cross-sectional area of the coolant discharge groove formed by partially cutting off the outer peripheral wall of the shank shaft as described later is made as small as possible to achieve the shaft strength. Can be secured as necessary.
[0060]
Then, a part of the outer peripheral wall of the shank shaft was cut away from the through-hole, that is, the whole area in the axial direction was cut off so as not to communicate with the through-hole, so that the cut-off portion was formed as a coolant and chip discharge groove. From a manufacturing standpoint, it is only necessary to cut a part of the shank shaft in the axial direction, so that the manufacturing is easy.
[0061]
Further, by cutting off a part of the outer peripheral wall of the shank shaft avoiding the through hole, a part of the outer peripheral surface of the through hole is exposed at the bottom of the cut part. The portion is formed by a gap surrounded by the exposed outer peripheral surface of the through hole and a cut end surface obtained by cutting a part of the shank shaft, and the cut portion is formed outside the through hole formed with a large diameter. Therefore, the cross-sectional area is smaller than the cross-sectional area of the coolant discharge groove having a V-shaped cross section passing through the axis of the conventional shank shaft, but the coolant supply capacity of the coolant supply passage is improved as described above. Accordingly, even if the cross-sectional area of the coolant discharge groove is somewhat reduced, the flow rate of the coolant is rather increased, and the chip discharge capability can be significantly improved.
[0062]
According to the invention according to claim 2, since the cutting head is provided detachably from the shank shaft, a conventional cutting head can be used when any one of the cutting head and the shank shaft needs to be replaced due to wear or defect. Since only the worn or missing parts need to be replaced, the repair cost is lower as compared with the one integrated with the shaft and the shank shaft.
[0063]
Furthermore, when switching to another cutting operation such as drilling and reaming, it is possible to easily switch from drilling to reaming by simply changing this cutting head, while the shank shaft is continuously used. can do.
[0064]
As described above, since the cutting head 4 is connected to the shank shaft 3 by the screw connection, the connection structure between the two can be manufactured simply and inexpensively. The replacement work of the parts can be easily performed.
[0065]
According to the invention according to claim 3, since the shank shaft is composed of a plurality of shank shaft members which are screwed to each other, if a plurality of shank shaft members having different lengths are prepared, the shank shaft members are replaced. The shank length can be changed, and without changing the shank shaft member having the driver portion on the base end side, an appropriate shank length according to the drilling depth to be applied can be set, and the shank shaft member When wear, breakage, deformation, etc. occur, only the shank shaft member can be replaced and used continuously.
[0066]
According to the invention according to claim 4, it becomes possible to connect a plurality of shank shaft members as needed, or to connect a cutting head to the shank shaft members to perform required cutting.
[0067]
According to the fifth aspect of the present invention, if each screw engaging portion between the shank shaft members or between the shank shaft member and the cutting head is a square screw, the coupling strength is increased and a gap is hardly generated. Coolant leakage from the joint can be prevented.
[0068]
In addition, incomplete screw portions on the distal end side of the male screw and the open end side of the female screw in each screw engaging portion between the shank shaft members or between the shank shaft members and the cutting head do not exist within the formation range of the discharge groove. In this state, a screw end having a complete end face faces the cut end surface forming the discharge groove, so that no gap is generated. Therefore, it is possible to prevent a problem that chips are caught in the gap and cannot be discharged smoothly. .
[0069]
According to the sixth aspect of the present invention, the coolant discharge groove is formed in a portion of the outer peripheral wall of the shank shaft that is cut off, but the radial depth of the portion, that is, the shank shaft. The depth of the cut end face from which the outer peripheral wall has been cut off and the amount of cut of the outer peripheral wall in the circumferential direction of the shank axis can be freely set within the above-described range, whereby the coolant discharge ability, and thus the cutting of the workpiece can be performed. The ability to discharge chips generated in the hole can be freely adjusted.
[0070]
According to the seventh aspect of the present invention, the cutting head is provided with a cemented carbide tip, which is a cutting blade, so that the head body has an opening having a V-shaped cross section substantially 90 ° from the center. Has to be formed, which makes it impossible to form a supply channel consisting of the above-mentioned cutout as is formed in other parts. For this reason, in the present invention, since one or more coolant discharge ports are provided in communication with the coolant supply passage side on the shank shaft side, the head main body is approximately 90 ° from the center thereof. Can be formed, and the ability to discharge chips and coolant is not hindered.
[Brief description of the drawings]
1A and 1B show a gun drill according to an embodiment of the present invention, in which FIG. 1A is a partially omitted front view showing an entire configuration, FIG. 1B is an enlarged view of an imaginary line circle B in FIG. 1A, and FIG. FIG. 4A is an enlarged view of the inside of a virtual line circle C of FIG.
2A and 2B show a base shank shaft member used for the gun drill of the embodiment, wherein FIG. 2A is a partially omitted front view showing the entire configuration, FIG. 2B is a side view seen from the tip, and FIG. It is arrow sectional drawing of CC line.
3A and 3B show an intermediate shank shaft member used for the gun drill according to the embodiment, FIG. 3A is a partially omitted front view showing the entire configuration, FIG. 3B is a side view seen from the tip, and FIG. 5 is a sectional view taken along line CC of FIG.
4A and 4B show a cutting head used in the gun drill of the embodiment, wherein FIG. 4A is a partially omitted front view showing the entire configuration, FIG. 4B is a side view seen from the tip, and FIG. FIG. 3D is a cross-sectional view taken along line C, and FIG.
FIG. 5 is a front view of a gun drill showing another embodiment of the present invention.
FIGS. 6 (a) and (b) are a schematic configuration of a conventionally used gun drill system and a sectional view of a gun drill used therefor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Coolant discharge groove 2 Coolant supply passage 3 Shank shaft 4 Cutting head 7 Through hole 8 Cutout portion 9 Shank shaft member 9A Base shank shaft member 9B Intermediate shank shaft member 9C Head shank shaft member 10 Screw coupling portion 5d Male screw 5b Female screw 13 Screw connection part 13a Incomplete screw part 15 Discharge port 16 Driver part

Claims

A shank shaft provided with a coolant discharge groove in the outer peripheral portion and a coolant supply passage therein, and a deep hole cutting tool having a cutting head at the tip of the shank shaft, concentric with the shank shaft. A through-hole is provided in substantially the entire axial direction, the through-hole forms the coolant supply passage, and a part of the outer peripheral wall of the shank shaft is cut linearly in substantially the entire axial direction avoiding the through-hole. A deep hole cutting tool, wherein the cut portion forms the coolant discharge groove.

2. The deep hole cutting tool according to claim 1, wherein the shank shaft is provided with a cutting head at a tip end thereof, which is detachably provided by screw connection.

The deep hole cutting tool according to claim 1, wherein the shank shaft includes a plurality of shank shaft members, and the shank shaft members are detachably screwed to each other.

One of the threaded joints on both sides of the shank shaft member constitutes a male thread and the other constitutes a female thread, and the threaded joint between the shank shaft member and the cutting head has the same size and shape as the threaded joint between the shank shaft members. The deep hole cutting tool according to claim 1, wherein:

The screw used for the screw connection is a square screw, and the incompletely threaded portion of the male screw at the end side of the male screw and the open end side of the female screw is not included in the range for forming the coolant discharge groove. The deep hole cutting tool according to any one of claims 1 to 4, wherein

In the coolant discharge groove on the outer periphery of the shank shaft, the depth of the cut surface in the direction perpendicular to the shaft is a ratio of 1/2 to 1/4 of the radius of the shank shaft, and approximately 1/1 of the entire circumference in the circumferential direction. The deep hole cutting tool according to any one of claims 1 to 5, wherein the tool is formed so as to have a length of 3 to 1/5.

The deep hole cutting tool according to any one of claims 1 to 6, wherein the cutting head is provided with one or more coolant discharge ports in communication with a coolant supply passage on the shank shaft side.