JP4090248B2 - Throw-away tip for deep hole cutting and throw-away drill for deep hole cutting - Google Patents

Description

からなる内切刃角γの没入刃先部８が形成されてなる深孔切削用スローアウエイチップに係る。
【０００６】
請求項２に係る発明は、前記没入刃先部８のすくい面９に傾斜段部１０が形成されてなる請求項１に記載の深孔切削用スローアウエイチップに係る。
【０００７】
請求項３に係る発明は、前記没入部６は前記ボルト孔１を挟んでチップ本体４の対称位置に一対形成されてなる請求項１又は２に記載の深孔切削用スローアウエイチップに係る。
【０００８】
請求項４に係る発明は、ドリルヘッド１２の先端部にその軸心側から外周側にかけて複数のスローアウエイチップ１１ａ〜１１ｃ（以下、チップ１１ともいう）がボルト１３によって取着されてなる深孔切削用スローアウエイドリルにおいて、該チップ１１は、請求項１または２に記載のチップからなり、このうち、軸心側のチップ１１ａは、その没入刃先部８がドリルヘッド１２の回転軸心Ｏに対して若干芯下がり位置にくるよう設けられ、これによって、該ドリルヘッド１２の回転軸心Ｏ付近に前記没入刃先部８の前記芯下がり量ε（正確には、２×ε）に相当する非切削ゾーン１４が形成されてなる深孔切削用スローアウエイドリルに係る。
【００１０】
請求項５に係る発明は、前記没入部６はボルト孔２を挟んでチップ本体４の対称位置に一対形成されてなる請求項４に記載の深孔切削用スローアウエイドリルに係る。
【００１１】
【発明の実施の形態】
図１〜図４は、本発明の一実施形態のチップ１１を示すもので、先ず図１に示すように、チップ本体４は、正面視略平行四辺矩形状を呈し、その中心部に正面１５から後面１６に向かって貫通するボルト孔１が形成され、図中上下部端縁は緩やかに平行に傾斜して、これに外切刃角α（例えば１２°）の刃先部２，２が形成され、両刃先部２の正面側に図２をも参照してＪ状に没入したチップブレーカー１７，１７が形成され、両刃先部２の背面側に後部側にかけて前逃げ角β（例えば１１°）の逃げ面３，３が形成される。
【００１２】
そして、図１、図２および図３に示すように、チップ本体４の刃先部２の一端縁側の本体側面５（図３）に刃先部一端縁２ａを含む本体側面５の一部が没入した没入部６が形成される。即ち、本体側面５は、その正面１５側から裏面１６側にかけて前記逃げ面３と同じ傾斜度の傾斜面に形成され、正面１５寄り部分が最も大きく突出しているが、この本体側面５の突出部分を切欠するように、本体側面５を図３に示すように裏面側に向かって正面側から直角ｘに切欠することによって本体側面５の一部に没入部６が形成され、これによって該没入部６に前記刃先部２、正確には刃先部一端縁２ａに連続した没入端縁７と該端縁７に続く没入側面９（図１、図２）と該没入側面９のから傾斜状に延びる傾斜段部１０（図１、図３）とが形成される。そして、この没入端縁７は、後述のように内切刃角γの没入刃先部８を形成することになり、これが本発明の最大の特徴とするものである。なお、また没入側面９は該没入刃先部８のすくい面９を形成することなる。
【００１３】
以上の構造からなる没入部６は、図１、図３および図４から明らかなように、ボルト孔１を中心点としてチップ本体４の点対称位置に一対形成されている。なお、図１、図２において、１８，１９はチップ本体３の正面側に両側面５，５にかけて形成される面取り部である。
【００１４】
上記の実施形態からなるチップ１１は、図７または図８に示すように、その刃先部２がドリルヘッド１２の回転中心Ｏを通る中心線ＣＬからＲ量だけ芯上がり位置に取着される。
【００１５】
図５〜図６は、上記構造からなるチップ１１をドリル本体２０の先端部のドリルヘッド１２に取着した状態を示すもので、ドリルヘッド１２の回転軸心Ｏから中心線ＣＬ方向にその軸心部側と中間部と外周部側との３箇所に３つのチップ１１（１１ａ，１１ｂ，１１ｃ）がボルト１３によって取着されており、このうち、軸心側のチップ１１ａは、その回転軸心Ｏ付近に取着されることによって、図６、特に図７、更に図８に示すように、該軸心Ｏとチップ１１（１１ａ）の前記没入端縁７との間に若干の空隙、例えば幅が０．８ｍｍ程度の非切削ゾーン１４が形成される。なお、図５及び図６において、２１，２２はドリルヘッド１２及びドリル本体２０にそれぞれ連通して開口される切屑排出用の孔、２３はボルト止めされたガイドパットである。
【００１６】
また図７、図８に示すように、チップ１１ａは、その没入端縁７がドリルヘッド１２の回転軸心Ｏを通る中心線ＣＬより、例えば０．４ｍｍの芯下がり量εを有する位置にくるよう取り付けられる。
【００１７】
この状態で、チップ１１ａが面Ｐ及び面Ｑ、即ち、刃先部２及び没入端縁７を図中反時計方向ａに回転させることによって、没入端縁７が内切刃角γを有する切刃部８として作用を果たし、その芯下がり量εに相当するコア、正確には、芯下がり量ε×２の直径に相当するコアＣが生成形成される。
【００１８】
その理由を以下に述べると、まず、図１４に示すように、トリルヘッド１２に取着した複数のスローアウエイチップＳａ，Ｓｂにおいて、外周部側の切削を担当する外切刃Ｓｂに対して、中心部側を切削するためにドリルヘッド１２の回転中心Ｏをオーバーラップして取り付けた内切刃Ｓａには、図１４の一部を取り出し、拡大して示すように、必ず内切刃角Θが必要である。
【００１９】
そのため、従来にあっては、図１４に示すように、外周部側の切削を担当する外切刃Ｓｂには、外切刃角αを有する外切刃Ｓｂを取着し、中心部側の切削を担当する内切刃Ｓａには、内切刃角Θを有する内切刃Ｓａを取着するようにしていた。
【００２０】
これがために、当然のことながら、従来にあっては、構造の異なった複数種類の切刃をドリルヘッドに取り付ける必要があった。
【００２１】
本発明は、図５に示すように、外切刃１１ｃ、中間切刃１１ｂ及び内切刃１１ａの何れも外切刃角αを有する切刃を用いることができ、特に外切刃角αを有する内切刃１１ａによっても、中心部側の切削が可能とする構成を該切刃１１ａに付与したことを特徴とするもので、後述のように（図８）、外切刃角αを有する内切刃１１ａに内切刃角γを有する没入刃先部８を付与することよって、中心部側の切削が可能としたものである。
【００２２】
図７、特に図８のように、切刃部２は中心線ＣＬからＲ量だけ芯上がり状態に取り付けられ、これによって没入端縁７は中心線ＣＬを直交してＲ量だけオーバーラップして設けられている。
【００２３】
そして、回転中心Ｏを中心に矢印ａの方向にチップ１１ａが回転する際に、没入端縁７が内切刃角を有するので、Ｒ量オーバーラップした部分の没入端縁７が内切刃として、即ち、没入刃先部８としての作用を果たすことができる。
【００２４】
即ち、図８において、刃先部２の外切刃角をαとし、該刃先部２の前逃げ角をβとすれば、没入端縁７によって、後述の計算式による合成角γとしての内切刃角γの没入刃先部８が得られる。そして、回転軸心Ｏを基準として面Ｐと面Ｑとを同一平面に並ぶよう反時計方向に展開すると図９に示すようになる。
【００２５】
図８の状態からも分かるように、チップ１１ａは、刃先部２が外切刃角αを有する切刃として、また没入刃先部８は内切刃角γを有する内切刃として、夫々別の面に形成され、該没入刃先部８が回転軸心Ｏを中心に回転することによって、回転軸心Ｏから没入刃先部８の芯下がり量εに相当する半径の被削材を切削することになり、図示のように、該没入刃先部８の芯下がり量ε×２に相当する直径のコアＣが生成形成されることになる。このコアＣの生成時には没入刃先部８は切削刃としての役割を担うので、切削抵抗を受けることが少なく、長期間使用するも切刃の折損を可及的に少なくすることが可能となる。
【００２６】
没入刃先部８の内切刃角γ、即ち、外切刃角αと前逃げ角βとによって得られる合成角γは、次の計算式から、

となる。
【００２７】
図１０において、チップ１１ａの没入端縁７の厚さをＴとし、刃先部２の外切刃角をαとし、逃げ面３の前逃げ角をβとすると、Ａ部拡大図に示すように、点ｏから外切刃角αに直角となる補助線α１を引き、該補助線α１と前逃げ角βによりできる隠れ線β１の延長線との交点をＱとすると、
ここでｏ−Ｑは、前逃げ角βと厚さＴとの関係なので、

となる。
【００２８】
また、上述のように、没入刃先部８が内切刃角γを有して回転軸心Ｏ側の切削が可能であるが、該没入刃先部８によって、上述のように芯下がり量ε〔ｍｍ〕を半径とするコアＣが生成形成されるが、没入刃先部８の内切刃角γ、芯下がり量ε及び没入刃先部８の送り量ｓによっては、被削材との間で干渉が起こる場合があるので、没入刃先部８の芯下がり量εと送り量ｓは干渉の起こらない領域の条件に設定する必要がある。
【００２９】
これを計算式で表すと、図１１及び図１２において、芯下がり量ε〔ｍｍ〕を半径とするコアＣが発生するとき、このコアＣと没入刃先部８とが接触する点Ｐは送り量ｓ〔ｍｍ／rev]により螺旋状に移動する。このときの円周と点Ｐとのなす角度をθ〔°〕とすると、図１１及び図１２に示す図を計算式で表すと、

が成り立つ。
ゆえに、内切刃角γを有する没入刃先部８の被削材に対する干渉が起こらない領域は、

と表すことができる。
即ち、没入刃先部８の芯下がり量εと送り量ｓは、

と同じか又はそれ以上の領域に設定する必要がある。
【００３０】
次に孔明け切削過程において起きる現象について述べると、図７および図１３に示すように、矢印方向ａに回転するチップ１１によって切削が進行するにつれて、当然に被削材Ｗがチップ１１の刃先部２で切削され、切削された切削屑はチップブレーカー１７（図５、図６、図７）に細かく折り取られ排出されるが、このうち、軸心側に位置するチップ１１ａには、前述のように、その刃先部２の一端縁２ａに直交して連続して、回転軸心Ｏに対して芯下がり量εを有する内切刃角γの没入刃先部８が形成されており、これがために、チップ１１ａの回転にともなって、回転軸心Ｏと芯下がり量εとの距離、例えば回転軸心Ｏから０．４ｍｍの位置で、該没入刃先部８が被削材を切削し、回転軸心Ｏから０．４ｍｍまでの被削材は切削されないで非切削ゾーン１４を形成し、ここで、０．４ｍｍを半径とするコアＣが生成形成される。
【００３１】
そして、本発明の実施形態においては、前記没入部６の没入側面９は没入刃先部８のすくい面９に相当し、これにチップブレーカーに相当する傾斜段部１０が形成されているため、非切削ゾーン１１で成長するコアＣは、図１３に示すように、その成長途上で傾斜段部１０に衝突し、コアＣの成長にともなって傾斜段部１０への衝突圧力が確実に強くなり、しかも、該段部１０は傾斜面に形成されているため、傾斜面に沿う折り取り方向への負荷が強力に働いて、コアＣは強制的に且つ確実に該傾斜段部１０によって折り取られ脱落されることになる。
【００３２】
また本発明の実施態様の特徴とする構造は、図１および図４に示すように、前記没入部６は前記ボルト孔１を挟んでチップ本体４の対称位置に一対形成されてなることである。
【００３３】
これがために、ドリルヘッド１２の外周側に取着されたチップ１１ｃの傾斜段部１０は、ドリルヘッド１２の外周面に沿ってなだらかな流線状に傾斜して連続することになる。
【００３４】
ドリルヘッド１２が被削材中に切削進行して、その切削作業が終了したときには、ドリルヘッド１２を被削材中から引き抜くことになるが、その際に従来であればドリルヘッド１２の外周面に位置するチップの外周面側に突出している部分が一種のかえりとなって、切削孔の切削壁を傷つけることがあったが、本発明の実施形態によれば、前述のようにドリルヘッド１２の外周面側に突出している部分は傾斜段部１０に形成され、ドリルヘッド１２の外周面に対して流線状に連続しているため、ドリルヘッド１２の引抜きの際に該チップ１１ｃによって切削壁を傷つけることはない。
【００３５】
なお、本発明の実施形態によれば、当然のことながら、一方側の刃先部２が摩耗すれば、チップ本体４を１８０°反転させて、他方の刃先部２を使用することができるから、それだけ長期間にわたって使用することができる。
【００３６】
また従来であれば、チップをドリルヘッド１２に取着する際に、その軸心側、中間側および外周面側に夫々構造や形状の異なった専用のチップを取着する必要があり、それだけ取着作業が面倒であったが、本発明の実施形態にあっては、図５および図６に示すように、同一構造及び形状の一種類のチップ１１（１１ａ，１１ｂ，１１ｃ）を、その軸心側、中間側および外周面側に夫々取着することができるから、それだけ部品点数を少なくすることができ、また取着作業も能率的に行うことができる。
【００３７】
【発明の効果】
請求項１に係る発明の深孔切削用スローアウエイチップによれば、中心部にボルト孔１を有し、周縁に外切刃角αの刃先部２を有し、刃先部２から後部にかけて前逃げ角βの逃げ面３を有してなるチップ本体４の刃先部２一端縁側の本体側面５に刃先部２一端縁２ａを含む本体側面５の一部が没入した没入部６が形成され、該没入部６の刃先部の一端縁２ａに該刃先部２に直角に連続して後部側に延びる没入端縁７が形成され、該没入端縁７によって、没入刃先部８が形成されてチップ１１をドリルヘッド１２の回転軸心Ｏに対して、該没入刃先部８が若干の芯下がり量εを有して前記ボルト孔１によってボルト止めすることによって、ドリルヘッド１２の回転軸心Ｏの付近に非切削ゾーン１４が形成されて、所謂、切削作用に阻害するチゼルエッジを除去することができるから、該チップ１１を使用することによって切削能力を格段に向上させることができる。
【００３８】
又、本発明の深孔切削用スローアウエイチップによれば、前記没入端縁７によって、前記外切刃角αと前記前逃げ角βとによってできる合成角γ、即ち

からなる内切刃角γの没入刃先部８が形成されてなるため、没入刃先部８によって回転軸心Ｏ付近の被削材を切削抵抗を少なくして切削することができ、それだけ没入刃先部８の折損を可及的に少なくし、安定して使用することができる。
【００３９】
又、ドリルヘッド１２に取着されるチップ１１には、その外周側切削を担当する外切刃角αを有する切刃部と、回転軸心Ｏ側切削を担当する内切刃角γを有する切刃の部分を備えてなるため、該チップ１１をドリルヘッド１２の軸心側、中間側および外周面側の何れにも同じ構造及び形状の一種類のチップのみを取着することができることになり、それだ製造面で有利となり、且つ取着部位でのチップの種類の選定作業を必要としないからチップ１１をドリルヘッド１２に迅速容易に取着することができる。
【００４０】
請求項２に係る発明の深孔切削用スローアウエイチップによれば、前記没入刃先部８のすくい面９に傾斜段部１０が形成されてなるため、切削作業途上で非切削ゾーン１４に生成成長するコアＣは、傾斜段部１０に当接して強制的に折り取られ、コアＣを細切れにして良好にドリルヘッド１２から排出することができる。
【００４１】
また請求項３に係る発明の深孔切削用スローアウエイチップよれば、前記没入部６は前記ボルト孔１を挟んでチップ本体４の対称位置に一対形成されてなるため、該チップをドリルヘッドに取着する際に、その軸心側では、該没入部がチゼルエッジを除去する役割を果たすと共に、その外周面側では、該没入部の傾斜段部がドリルヘッドの外周面に沿う流線形を呈し、ドリルヘッドの切削孔からの引抜き時において切削壁を損傷させることなく円滑にドリルヘッドを被削材の切削孔から引き抜くことができる。
【００４２】
また請求項４に係る発明の深孔切削用スローアウエイドリルによれば、ドリルヘッド１２の先端部にその軸心側から外周側にかけて複数のスローアウエイチップ１１ａ〜１１ｃ（以下、チップ１１ともいう）がボルト１３によって取着されてなる深孔切削用スローアウエイドリルにおいて、該チップ１１は、請求項１または２に記載のチップからなり、このうち、軸心側のチップ１１ａは、その没入刃先部８がドリルヘッド１２の回転軸心Ｏに対して若干芯下がり位置にくるよう設けられ、これによって、該ドリルヘッド１２の回転軸心Ｏ付近に前記没入刃先部８の前記芯下がり量ε（正確には、２×ε）に相当する非切削ゾーン１４が形成されてなるため、チップ１１をドリルヘッド１２の回転軸心Ｏに対して、該没入刃先部８が若干の芯下がり量εを有して前記ボルト孔１によってボルト止めされることによって、ドリルヘッド１２の回転軸心Ｏの付近に非切削ゾーン１４が形成されて、所謂、切削作用に阻害するチゼルエッジを除去することができるから、該チップ１１を使用することによって切削能力を格段に向上させることができる。
【００４３】
又、本発明の深孔切削用スローアウエイドリルによれば、前記没入端縁７によって、前記外切刃角αと前記前逃げ角βとによってできる合成角γ、即ち

からなる内切刃角γの没入刃先部８が形成されてなるチップ１１を取着してなるため、没入刃先部８によって回転軸心Ｏ付近の被削材を切削抵抗を少なくして切削することができ、それだけ没入刃先部８の折損を可及的に少なくし、長期にわたって安定して使用することができる。
【００４４】
又、ドリルヘッド１２に取着されるチップ１１には、その外周側切削を担当する外切刃角αを有する切刃部と、回転軸心Ｏ側切削を担当する内切刃角γを有する切刃の部分を備えてなるため、該チップ１１をドリルヘッド１２の軸心側、中間側および外周面側の何れにも同じ構造及び形状の一種類のチップのみを取着することができることになり、それだ製造面で有利となり、且つ取着部位でのチップの種類の選定作業を必要としないからチップ１１をドリルヘッド１２に迅速容易に取着することができる。
【００４６】
又、請求項５に係る発明の深孔切削用スローアウエイドリルによれば、前記没入部６はボルト孔２を挟んでチップ本体４の対称位置に一対形成されてなるため、該チップをドリルヘッドに取着する際に、その軸心側では、該没入部がチゼルエッジを除去する役割を果たすと共に、その外周面側では、該没入部の傾斜段部がドリルヘッドの外周面に沿う流線形を呈し、ドリルヘッドの切削孔からの引抜き時において切削壁を損傷させることなく円滑にドリルヘッドを被削材の切削孔から引き抜くことができる。
【図面の簡単な説明】
【図１】 本発明の一実施形態に係るチップの正面図である。
【図２】 図１のIIーII線端面図である。
【図３】 同平面図である。
【図４】 図３のIVーIV線断面図である。
【図５】 本発明の一実施形態のチップをドリルヘッドに取着した状態の正面図である。
【図６】 同平面図である。
【図７】 同要部の拡大平面図である。
【図８】 同要部の作用を説明するための説明図である。
【図９】 同要部の作用を説明するための説明図である。
【図１０】 同要部の作用を説明するための説明図である。
【図１１】 同他の要部の作用を説明するための説明図である。
【図１２】 同他の要部の作用を説明するための説明図である。
【図１３】 同実施形態の作用を説明するための説明図である。
【図１４】 従来技術のドリルヘッドを示す正面図である。
【符号の説明】
１ ボルト孔
２ 刃先部
２ａ 刃先部一端縁
３ 逃げ面
４ チップ本体
５ 本体側面
６ 没入部
７ 没入端縁
８ 没入刃先部
９ すくい面
１０ 傾斜段部
１１ スローアウエイチップ
１２ ドリルヘッド
１３ ボルト
１４ 非切削ゾーン
α 外切刃角
β 前逃げ角
γ 合成角又は内切刃角
ε 芯下がり量
Ｏ 回転軸心
Ｃ コア[0001]
BACKGROUND OF THE INVENTION
The present invention particularly relates to a throw-away tip for deep hole cutting, that is, a disposable tip, and an improvement of a throw-away drill using the tip.
[0002]
[Prior art and issues]
When this type of throw-away tip is attached to the drill head in the radial direction with respect to the rotation axis, naturally, the tip edge of the tip is accurately positioned in order to cut to the center of the workpiece. You must pass through your heart. However, since the cutting speed at the center of the drill is theoretically zero, the cutting edge of this part is loaded with thrust resistance, so-called chisel edge, which is the part where the cutting force does not work. This is one of the reasons why we cannot improve our ability.
[0003]
In addition, the tip attached to the drill head must have an outer cutting edge angle on the outer peripheral side and an inner peripheral side on the outer peripheral side, and an inner cutting edge angle on the inner peripheral side. For example, the chip structure is different, which makes it difficult to reduce the manufacturing unit price.
[0004]
An object of the present invention is to propose a throw-away tip that has completely eliminated the above-mentioned difficulties and has dramatically improved cutting ability, and a throw-away drill using the tip.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention according to claim 1 has a bolt hole 1 at the center, a cutting edge 2 having an outer cutting edge angle α at the periphery, and a front clearance angle from the cutting edge 2 to the rear. A dip portion 6 is formed by immersing a part of the body side surface 5 including the blade edge 2 one end edge 2a on the body side surface 5 of the edge portion 2 of the tip body 4 having the flank surface 3 of β. An immersion edge 7 is formed at one end edge 2a of the blade edge portion of the portion 6 so as to be continuous to the blade edge portion 2 at a right angle and extending to the rear side, and the outer cutting edge angle α and the front clearance angle are formed by the immersion edge 7. a composite angle γ formed by β, that is,

This relates to a slow hole tip for deep hole cutting in which an immersion blade tip 8 having an inner cutting edge angle γ is formed.
[0006]
The invention according to claim 2 relates to the slow hole tip for deep hole cutting according to claim 1, wherein an inclined step portion 10 is formed on the rake face 9 of the immersive cutting edge portion 8.
[0007]
According to a third aspect of the present invention, there is provided the throw-away tip for deep hole cutting according to the first or second aspect, wherein the immersion portion 6 is formed in a pair at a symmetrical position of the tip body 4 with the bolt hole 1 in between.
[0008]
The invention according to claim 4, a plurality of indexable 11a~11c from the axis side at the tip of the drill head 12 to the outer side (hereinafter, it Moi chip 11) depth is being attached by bolts 13 In the slow-away drill for hole cutting, the tip 11 is composed of the tip according to claim 1, wherein the tip 11 a on the axial center side has an immersive cutting edge portion 8 whose rotational axis O of the drill head 12. With respect to the center axis of the drill head 12, it corresponds to the center down amount ε (more precisely, 2 × ε) of the immersion blade tip 8 in the vicinity of the rotational axis O of the drill head 12. The present invention relates to a deep hole cutting slow-away drill in which a non-cutting zone 14 is formed.
[0010]
The invention according to claim 5 relates to the slow hole drill for deep hole cutting according to claim 4, wherein a pair of the recessed portions 6 are formed at symmetrical positions of the tip body 4 with the bolt hole 2 interposed therebetween.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 to 4 show a chip 11 according to an embodiment of the present invention. First, as shown in FIG. 1, the chip body 4 has a substantially parallelogram shape when viewed from the front, and has a front surface 15 at the center thereof. Bolt holes 1 penetrating from the back to the rear surface 16 are formed, and the edges of the upper and lower portions in the figure are gently inclined in parallel to form the cutting edge portions 2 and 2 having an outer cutting edge angle α (for example, 12 °). In addition, chip breakers 17 and 17 that are immersed in a J shape are formed on the front side of both blade tips 2 with reference to FIG. 2, and a front clearance angle β (for example, 11 °) is formed on the back side of both blade tips 2 toward the rear side. ) Are formed.
[0012]
As shown in FIGS. 1, 2, and 3, a part of the main body side surface 5 including the cutting edge portion one end edge 2 a is immersed in the main body side surface 5 (FIG. 3) on one end edge side of the cutting edge portion 2 of the chip body 4. An immersive part 6 is formed. That is, the main body side surface 5 is formed on an inclined surface having the same inclination as the flank 3 from the front surface 15 side to the rear surface 16 side, and the portion closer to the front surface 15 protrudes the largest. As shown in FIG. 3, the main body side surface 5 is notched at a right angle x from the front side toward the back surface as shown in FIG. 3, thereby forming an immersion portion 6 in a part of the main body side surface 5. 6, the blade edge portion 2, more precisely, an immersion edge 7 continuous with the edge 1 a of the edge of the blade edge, an immersion side surface 9 (FIGS. 1 and 2) following the edge 7, and the immersion side surface 9 extend in an inclined manner. An inclined step 10 (FIGS. 1 and 3) is formed. The immersive edge 7 forms an immersive cutting edge portion 8 having an inner cutting edge angle γ as described later, which is the greatest feature of the present invention. In addition, the immersion side surface 9 forms the rake surface 9 of the immersion blade edge portion 8.
[0013]
As is apparent from FIGS. 1, 3, and 4, a pair of the immersing portions 6 having the above structure is formed at a point-symmetrical position of the chip body 4 with the bolt hole 1 as the center point. In FIGS. 1 and 2, reference numerals 18 and 19 denote chamfered portions formed on the front side of the chip body 3 on both side surfaces 5 and 5.
[0014]
As shown in FIG. 7 or FIG. 8, the tip 11 according to the above embodiment is attached to the center rising position by an amount R from the center line CL passing through the rotation center O of the drill head 12.
[0015]
5 to 6 show a state in which the tip 11 having the above structure is attached to the drill head 12 at the tip of the drill body 20, and the axis of the drill head 12 in the direction of the center line CL from the rotational axis O of the drill head 12 is shown. Three tips 11 (11a, 11b, 11c) are attached by bolts 13 at three locations of the central portion side, the intermediate portion, and the outer peripheral portion side, and among these, the tip portion 11a on the axial center side has its rotating shaft. By being attached in the vicinity of the center O, as shown in FIG. 6, particularly FIG. 7 and FIG. 8, a slight gap between the shaft center O and the immersion edge 7 of the tip 11 (11a), For example, the non-cutting zone 14 having a width of about 0.8 mm is formed. In FIGS. 5 and 6, reference numerals 21 and 22 denote chips discharging holes opened in communication with the drill head 12 and the drill main body 20, respectively, and reference numeral 23 denotes a bolted guide pad.
[0016]
Further, as shown in FIGS. 7 and 8, the tip 11 a comes to a position where the immersive end edge 7 has a core down amount ε of, for example, 0.4 mm from the center line CL passing through the rotation axis O of the drill head 12. It is attached as follows.
[0017]
In this state, the tip 11a rotates the surface P and the surface Q, that is, the cutting edge 2 and the immersion edge 7 in the counterclockwise direction a in the drawing, so that the immersion edge 7 has an inner cutting edge angle γ. The core 8 that functions as the portion 8 and that corresponds to the core drop amount ε, more precisely, the core C that corresponds to the diameter of the core drop amount ε × 2 is generated and formed.
[0018]
The reason for this will be described below. First, as shown in FIG. 14, in the plurality of throwaway tips Sa, Sb attached to the trill head 12, the outer cutting edge Sb in charge of cutting on the outer peripheral portion side, A part of FIG. 14 is taken out from the inner cutting edge Sa attached with the rotation center O of the drill head 12 overlapped in order to cut the center side. is required.
[0019]
Therefore, in the prior art, as shown in FIG. 14, the outer cutting edge Sb having the outer cutting edge angle α is attached to the outer cutting edge Sb in charge of cutting on the outer peripheral side, so that The inner cutting edge Sa having the inner cutting edge angle Θ is attached to the inner cutting edge Sa in charge of cutting.
[0020]
For this reason, as a matter of course, conventionally, it was necessary to attach a plurality of types of cutting blades having different structures to the drill head.
[0021]
In the present invention, as shown in FIG. 5, any of the outer cutting edge 11c, the intermediate cutting edge 11b, and the inner cutting edge 11a can use a cutting edge having an outer cutting edge angle α. The inner cutting edge 11a also has a configuration that allows the cutting of the central portion side to the cutting edge 11a, and has an outer cutting edge angle α as described later (FIG. 8). By providing the inner cutting edge 11a with an immersive cutting edge portion 8 having an inner cutting edge angle γ, cutting on the center side can be performed.
[0022]
As shown in FIG. 7, particularly FIG. 8, the cutting edge portion 2 is attached to the center-up state by an amount R from the center line CL, whereby the immersion edge 7 is overlapped by the amount R by intersecting the center line CL at right angles. Is provided.
[0023]
When the tip 11a rotates about the rotation center O in the direction of the arrow a, the immersive edge 7 has an inner cutting edge angle, so that the immersive edge 7 of the portion overlapping the R amount is used as the inner cutting edge. That is, the function as the immersion blade tip 8 can be achieved.
[0024]
That is, in FIG. 8, if the outer cutting edge angle of the cutting edge portion 2 is α and the front clearance angle of the cutting edge portion 2 is β, the inner cutting edge 7 will be used as a composite angle γ according to the calculation formula described later. An immersion blade tip 8 with a blade angle γ is obtained. Then, when the surface P and the surface Q are developed in the counterclockwise direction so as to be aligned on the same plane with the rotational axis O as a reference, the result is as shown in FIG.
[0025]
As can be seen from the state of FIG. 8, the tip 11 a is a separate cutting edge having a cutting edge portion 2 having an outer cutting edge angle α, and the immersive cutting edge portion 8 is a separate cutting edge having an inner cutting edge angle γ. By cutting the work piece formed on the surface and having a radius corresponding to the amount of core depression ε of the immersive cutting edge 8 from the rotating axis O, the immersive cutting edge 8 rotates about the rotation axis O. Thus, as shown in the figure, a core C having a diameter corresponding to the amount of core drop ε × 2 of the immersion blade tip 8 is generated and formed. Since the immersive cutting edge 8 plays a role as a cutting blade when the core C is generated, it is less likely to receive cutting resistance, and even when used for a long period of time, it is possible to reduce the breakage of the cutting blade as much as possible.
[0026]
The inner cutting edge angle γ of the immersive cutting edge 8, that is, the composite angle γ obtained by the outer cutting edge angle α and the front clearance angle β, is calculated from the following formula:

It becomes.
[0027]
In FIG. 10, when the thickness of the immersion edge 7 of the tip 11a is T, the outer cutting edge angle of the cutting edge portion 2 is α, and the front clearance angle of the flank 3 is β, When an auxiliary line α1 perpendicular to the outer cutting edge angle α is drawn from the point o and the intersection of the auxiliary line α1 and the extension line of the hidden line β1 formed by the front clearance angle β is Q,
Here, o-Q is the relationship between the front clearance angle β and the thickness T.

It becomes.
[0028]
Further, as described above, the immersive cutting edge 8 has the inner cutting edge angle γ and can be cut on the rotational axis O side. mm] is generated and formed, but depending on the inner cutting edge angle γ of the immersive cutting edge 8, the amount of core drop ε, and the feed amount s of the immersing cutting edge 8, interference with the work material occurs. Therefore, it is necessary to set the center down amount ε and the feed amount s of the immersive cutting edge 8 to the conditions of the region where no interference occurs.
[0029]
When this is expressed by a calculation formula, in FIG. 11 and FIG. 12, when a core C having a radius of the core down amount ε [mm] is generated, a point P where the core C and the immersive cutting edge portion 8 are in contact is a feed amount. It moves spirally by s [mm / rev]. If the angle formed by the circumference and the point P at this time is θ [°], the diagrams shown in FIG. 11 and FIG.

Holds.
Therefore, the region where the interference with the work material of the immersive cutting edge 8 having the inner cutting edge angle γ does not occur,

It can be expressed as.
That is, the amount of core drop ε and the feed amount s of the immersive cutting edge 8 are:

Must be set to the same or larger area.
[0030]
Next, the phenomenon that occurs in the drilling process will be described. As shown in FIGS. 7 and 13, as the cutting progresses by the tip 11 that rotates in the arrow direction a, the work material W naturally becomes the cutting edge portion of the tip 11. The cutting chips cut and cut by 2 are finely broken and discharged by the chip breaker 17 (FIGS. 5, 6, and 7). Of these, the chip 11a positioned on the axial center side has the above-mentioned Thus, an immersive cutting edge portion 8 having an inner cutting edge angle γ having a center-down amount ε with respect to the rotation axis O is formed continuously and orthogonally to the one end edge 2a of the cutting edge portion 2, In addition, with the rotation of the tip 11a, the immersion blade tip 8 cuts the work material at a distance between the rotation axis O and the amount of core drop ε, for example, a position 0.4 mm from the rotation axis O, and rotates. Work material from axis O to 0.4mm is not cut The non-cutting zone 14 is formed, wherein the core C of a 0.4mm radius is generated form.
[0031]
And in embodiment of this invention, since the immersion side 9 of the said immersion part 6 is equivalent to the rake face 9 of the immersion blade edge | tip part 8, and the inclination step part 10 equivalent to a chip breaker is formed in this, it is non- As shown in FIG. 13, the core C growing in the cutting zone 11 collides with the inclined step portion 10 during its growth, and the collision pressure on the inclined step portion 10 is surely increased as the core C grows. In addition, since the step portion 10 is formed on the inclined surface, the load in the folding direction along the inclined surface works strongly, and the core C is forcibly and surely broken off by the inclined step portion 10. It will be dropped out.
[0032]
1 and FIG. 4, the structure that characterizes the embodiment of the present invention is that a pair of the recessed portions 6 are formed at symmetrical positions of the chip body 4 with the bolt hole 1 interposed therebetween. .
[0033]
For this reason, the inclined step portion 10 of the tip 11c attached to the outer peripheral side of the drill head 12 is continuously inclined along the outer peripheral surface of the drill head 12 in a gentle streamline shape.
[0034]
When the drill head 12 has been cut into the work material and the cutting operation is completed, the drill head 12 is pulled out from the work material. However, according to the embodiment of the present invention, as described above, the drill head 12 may damage the cutting wall of the cutting hole. Since the portion protruding to the outer peripheral surface side is formed in the inclined step portion 10 and is continuous in a streamline shape with respect to the outer peripheral surface of the drill head 12, the tip 11 c is cut when the drill head 12 is pulled out. It won't hurt the wall.
[0035]
In addition, according to the embodiment of the present invention, as a matter of course, if the cutting edge portion 2 on one side is worn, the tip body 4 can be inverted 180 ° and the other cutting edge portion 2 can be used. It can be used for a long time.
[0036]
Further, conventionally, when attaching the tip to the drill head 12, it is necessary to attach dedicated tips having different structures and shapes to the axial center side, intermediate side and outer peripheral surface side, respectively. However, in the embodiment of the present invention, as shown in FIGS. 5 and 6, one type of chip 11 (11 a, 11 b, 11 c) having the same structure and shape is attached to its axis. Since it can be attached to the center side, the intermediate side, and the outer peripheral surface side, the number of parts can be reduced accordingly, and the attachment work can be performed efficiently.
[0037]
【The invention's effect】
According to the throw-away tip for deep hole cutting of the invention according to claim 1, the bolt hole 1 is provided at the center, the edge part 2 having the outer cutting edge angle α is provided at the periphery, and the front part extends from the edge part 2 to the rear part. An intrusion portion 6 is formed in which a part of the body side surface 5 including the edge portion 2 one end edge 2a is immersed in the body side surface 5 on the one end edge side of the tip portion 2 of the tip body 4 having the flank 3 of the clearance angle β. An immersion edge 7 is formed on one end edge 2a of the cutting edge portion of the immersion portion 6 and extends to the rear side continuously at a right angle to the cutting edge portion 2 , and an immersion blade edge portion 8 is formed by the immersion edge 7 to form a tip. 11 with respect to the rotational axis O of the drill head 12, the immersive cutting edge 8 has a slight core drop amount ε and is bolted by the bolt hole 1, so that the rotational axis O of the drill head 12 is fixed. A non-cutting zone 14 is formed in the vicinity, so-called chisel that inhibits cutting action Since the Tsu di can be removed, it is possible to greatly improve the cutting ability by the use of the chip 11.
[0038]
In addition, according to the throw-away tip for deep hole cutting of the present invention, the composite angle γ formed by the outer cutting edge angle α and the front clearance angle β by the immersive end edge 7, that is,

Since the immersive cutting edge portion 8 having the inner cutting edge angle γ is formed, the immersive cutting edge portion 8 can cut the work material near the rotation axis O with less cutting resistance, and the immersive cutting edge portion. 8 breakage can be reduced as much as possible, and it can be used stably.
[0039]
Further, the tip 11 attached to the drill head 12 has a cutting edge portion having an outer cutting edge angle α in charge of outer peripheral side cutting and an inner cutting edge angle γ in charge of rotation axis O side cutting. Since the cutting edge portion is provided, the tip 11 can be attached to only one type of tip having the same structure and shape on the axial center side, the intermediate side, and the outer peripheral surface side of the drill head 12. Thus, it is advantageous in terms of manufacturing and does not require the work of selecting the type of tip at the attachment site, so that the tip 11 can be quickly and easily attached to the drill head 12.
[0040]
According to the slow hole tip for deep hole cutting of the invention according to claim 2, since the inclined step portion 10 is formed on the rake face 9 of the immersive cutting edge portion 8, it is generated and grown in the non-cutting zone 14 during the cutting operation. The core C to be pressed comes into contact with the inclined step portion 10 and is forcibly broken, and the core C can be finely cut and discharged from the drill head 12 satisfactorily.
[0041]
Further, according to the deep hole cutting throw-away tip of the invention according to claim 3, since the immersing portion 6 is formed in a pair at a symmetrical position of the tip body 4 with the bolt hole 1 in between, the tip is used as a drill head. At the time of attachment, the immersive part serves to remove the chisel edge on the axial center side, and the inclined stepped part of the immersive part exhibits a streamline along the outer peripheral surface of the drill head on the outer peripheral surface side. The drill head can be smoothly pulled out from the cutting hole of the work material without damaging the cutting wall when the drill head is pulled out from the cutting hole.
[0042]
According to the deep hole cutting throw-away drill of the invention according to claim 4, a plurality of indexable 11 a to 11 c (hereinafter to the outer side from the axis side at the tip of the drill head 12 will Moi chip 11 ) Is attached by a bolt 13, and the tip 11 includes the tip according to claim 1, wherein the tip 11 a on the axial center side is the tip of the immersion blade. The portion 8 is provided so as to be slightly lowered with respect to the rotational axis O of the drill head 12, and thereby, the amount of core downward ε (of the immersion blade tip 8 near the rotational axis O of the drill head 12. Precisely, a non-cutting zone 14 corresponding to 2 × ε) is formed, so that the tip 11 is slightly below the center of the tip 11 with respect to the rotational axis O of the drill head 12. By being bolted by the bolt hole 1 with a screw amount ε, a non-cutting zone 14 is formed in the vicinity of the rotational axis O of the drill head 12 and so-called chisel edges that hinder cutting action are removed. Therefore, the cutting ability can be remarkably improved by using the tip 11.
[0043]
In addition, according to the deep hole cutting slow-away drill of the present invention, the sunk end edge 7 makes a composite angle γ formed by the outer cutting edge angle α and the front clearance angle β, that is,

Since the tip 11 formed with the immersive cutting edge portion 8 having the inner cutting edge angle γ is attached, the workpiece near the rotational axis O is cut by the immersive cutting edge portion 8 with less cutting resistance. Therefore, the breakage of the immersion blade edge portion 8 can be reduced as much as possible, and it can be used stably over a long period of time.
[0044]
Further, the tip 11 attached to the drill head 12 has a cutting edge portion having an outer cutting edge angle α in charge of outer peripheral side cutting and an inner cutting edge angle γ in charge of rotation axis O side cutting. Since the cutting edge portion is provided, the tip 11 can be attached to only one type of tip having the same structure and shape on the axial center side, the intermediate side, and the outer peripheral surface side of the drill head 12. Thus, it is advantageous in terms of manufacturing and does not require the work of selecting the type of tip at the attachment site, so that the tip 11 can be quickly and easily attached to the drill head 12.
[0046]
Further, according to the deep hole cutting throw-away drill of the invention according to claim 5 , since the immersing portion 6 is formed in a pair at the symmetrical position of the tip body 4 with the bolt hole 2 interposed therebetween, the tip is inserted into the drill head. At the axial center side, the immersive part serves to remove the chisel edge, and on the outer peripheral surface side, the inclined step portion of the immersive part has a streamline along the outer peripheral surface of the drill head. The drill head can be smoothly pulled out from the cutting hole of the work material without damaging the cutting wall when the drill head is pulled out from the cutting hole.
[Brief description of the drawings]
FIG. 1 is a front view of a chip according to an embodiment of the present invention.
FIG. 2 is an end view taken along line II-II in FIG.
FIG. 3 is a plan view of the same.
4 is a cross-sectional view taken along line IV-IV in FIG.
FIG. 5 is a front view of a state in which a tip according to an embodiment of the present invention is attached to a drill head.
FIG. 6 is a plan view of the same.
FIG. 7 is an enlarged plan view of the main part.
FIG. 8 is an explanatory diagram for explaining the operation of the main part.
FIG. 9 is an explanatory diagram for explaining the operation of the main part.
FIG. 10 is an explanatory diagram for explaining the operation of the main part.
FIG. 11 is an explanatory diagram for explaining the operation of the other main part.
FIG. 12 is an explanatory diagram for explaining the operation of the other main part.
FIG. 13 is an explanatory diagram for explaining the operation of the embodiment.
FIG. 14 is a front view showing a conventional drill head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bolt hole 2 Cutting edge part 2a Cutting edge part one edge 3 Relief face 4 Tip body 5 Body side surface 6 Immersion part 7 Immersion edge 8 Immersion cutting edge part 9 Rake face 10 Inclined step part 11 Throw away tip 12 Drill head 13 Bolt 14 Non-cutting Zone α Outer cutting edge angle β Front clearance angle γ Composite angle or inner cutting edge angle ε Centering down amount O Rotational axis C Core

Claims (5)

The cutting edge portion of the chip body 4 having a bolt hole 1 in the center, a cutting edge portion 2 having an outer cutting edge angle α on the periphery, and a flank 3 having a front clearance angle β from the cutting edge portion 2 to the rear portion. The main body side surface 5 on the one end edge side is formed with an immersion portion 6 in which a part of the main body side surface 5 including the one end edge 2a of the blade edge portion 2 is immersed, and the one end edge 2a of the blade edge portion of the immersion portion 6 is perpendicular to the blade edge portion 2 A dip end edge 7 continuously extending to the rear side is formed, and by the dip end edge 7, a composite angle γ formed by the outer cutting edge angle α and the front clearance angle β, that is,

A slow hole tip for deep hole cutting, in which an immersive cutting edge portion 8 having an inner cutting edge angle γ is formed.   The throwaway tip for deep hole cutting according to claim 1, wherein an inclined step portion 10 is formed on the rake face 9 of the immersive cutting edge portion 8.   The throw-away tip for deep hole cutting according to claim 1 or 2, wherein a pair of the immersing portions 6 are formed at symmetrical positions of the tip body 4 with the bolt hole 1 in between. A plurality of indexable 11a~11c to the outer side from the axis side at the tip of the drill head 12 (hereinafter, will Moi chip 11) is in the slow-away drill deep hole cutting made is attached by bolts 13, The tip 11 is composed of the tip according to claim 1 or 2, and the tip 11 a on the axial center side of the tip 11 is slightly lowered from the rotational axis O of the drill head 12. As a result, a non-cutting zone 14 corresponding to the center down amount ε (more precisely, 2 × ε) of the immersion blade tip 8 is formed in the vicinity of the rotational axis O of the drill head 12. Throw away drill for deep hole cutting. 5. The deep hole cutting throw-away drill according to claim 4 , wherein a pair of the recessed portions 6 are formed at symmetrical positions of the tip body 4 with the bolt hole 2 interposed therebetween.

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