JP4288905B2

JP4288905B2 - Replaceable cutting tool and ring member

Info

Publication number: JP4288905B2
Application number: JP2002209835A
Authority: JP
Inventors: 良彦木村; 太郎阿部
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2002-07-18
Filing date: 2002-07-18
Publication date: 2009-07-01
Anticipated expiration: 2022-07-18
Also published as: JP2004050335A

Description

【０００１】
【発明の属する技術分野】
本発明は、刃部が着脱可能に工具本体に装着される刃部交換式切削工具に関するものである。
【０００２】
【従来の技術】
従来、この種の刃部交換式切削工具の一例として、特許第２６５６９４９号公報に開示されているようなものがある。
図２に示すように、このような刃部交換式切削工具１の工具本体２には、その先端面２Ａに、軸線Ｏ方向の後端側に向かって取付孔３が穿設されており、この取付孔３は、先端面２Ａに開口するとともに後端側に向かうにしたがい内径が漸次縮径する略円錐台状のテーパ孔３Ａと、このテーパ孔３Ａの後端側に連なる雌ねじ部３Ｂとから構成されている。
また、少なくとも一つの切刃を備えた切削部４Ａとこの切削部４Ａの後端側に連なるとともに後端側に向かうにしたがい外径が漸次縮径する略円錐台状のテーパ部４Ｂとを有する刃部４における後端に形成されたフック部４Ｃと、雄ねじ部５Ｂを有するボルト部５における先端に形成されたフック部５Ａとが着脱可能に連結され、これら連結された刃部４及びボルト部５が、工具本体２の取付孔３内に挿入されている。
【０００３】
そして、ボルト部５の雄ねじ部５Ｂが取付孔３の雌ねじ部３Ｂにねじ込まれていることによって、ボルト部５が工具本体２の軸線Ｏ方向の後端側に引き込まれるのにともない、このボルト部５と連結された刃部４も軸線Ｏ方向の後端側に引き込まれていて、刃部４のテーパ部４Ｂの外周面が取付孔３のテーパ孔３Ａの内周面を押圧した状態となって、刃部４が工具本体２に着脱可能に装着されている。
なお、刃部４が工具本体２に装着された状態では、工具本体２の先端面２Ａと、この先端面２Ａに対向して配置されるとともに刃部４における切削部４Ａとテーパ部４Ｂとを接続する軸線Ｏ方向の後端側を向く壁面４Ｄとは密着せずに、これらの間に隙間が形成されている。
【０００４】
【発明が解決しようとする課題】
上記のような刃部交換式切削工具１では、作業者が刃部４を回転させることにより、この刃部４と連結されたボルト部５を回転させて、ボルト部５の雄ねじ部５Ｂを取付孔３の雌ねじ部３Ｂにねじ込み、ボルト部５及び刃部４を軸線Ｏ方向の後端側に引き込んでいくことになるのであるが、このときの刃部４を回転させるために与えられる締め付けトルクは、作業者の力の入れ加減で大きく変わってしまう。
作業者が力を入れ過ぎると、刃部４が取付孔３の奥深くまで入り過ぎてしまい、テーパ部４Ｂの外周面とテーパ孔３Ａの内周面との間で生じる押圧力が（くさび効果によって）非常に高くなって、刃部４を工具本体２から取り外すことができなくなるおそれがある。
さらに、ワークの切削加工の際には、切削熱の発生によって例えば鋼からなる工具本体２が熱膨張することや、工具本体２が高速回転するときに遠心力が生じることなどによって、取付孔３のテーパ孔３Ａが膨らんでしまうことがあり、このような場合も、刃部４が取付孔３の奥深くまで入り過ぎてしまうおそれを生じさせて、刃部４の取り外しができなくなるおそれがある。
【０００５】
また、上記のような刃部交換式切削工具１において、刃部４が工具本体２に装着された状態では、刃部４のテーパ部４Ｂの外周面と取付孔３のテーパ孔３Ａの内周面とを密着させることだけで、この刃部４を拘束しているために、刃部４の取付剛性が不足しがちとなっていて、切削加工時にビビリ振動を生じさせてしまうおそれがある。
これを解決するため、テーパ部４Ｂの外周面とテーパ孔３Ａの内周面とを密着させるのと同時に、工具本体２の先端面２Ａとこの先端面２Ａに対向して配置される刃部４の壁面４Ｄとを密着させるといった、いわゆる２面拘束にすることが考えられるが、このような刃部４の２面拘束を実現するためには、テーパ部４Ｂの外周面及びテーパ孔３Ａの内周面と、工具本体２の先端面２Ａ及び刃部４の壁面４Ｄとがそれぞれ高精度に加工されていることが必要となるので、効果的な解決手段とはなり得なかった。
【０００６】
ここで、刃部４のテーパ部４Ｂを中空にして、刃部４のテーパ部４Ｂの外周面が取付孔３のテーパ孔３Ａの内周面を押圧したときに、この刃部４のテーパ部４Ｂの外径が縮径するように弾性変形させて、上記の加工精度の誤差を吸収して２面拘束を実現する方法も考えられるが、このような刃部交換式切削工具１に用いられる刃部４を構成する材料としては、超硬質物質（超硬合金、サーメット、セラミック等）が使用されるため、加工の観点からテーパ部４Ｂを中空にすることは困難であり、また、外径が小さい（例えば２０ｍｍ以下）小径の工具になってくると強度低下の問題も生じてしまう。
【０００７】
本発明は、上記課題に鑑みてなされたもので、刃部の工具本体への着脱に不具合を生じさせることなく、刃部の取付剛性を容易に高めることができる刃部交換式切削工具及びリング部材を提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記の課題を解決して、このような目的を達成するために、本発明による刃部交換式切削工具は、少なくとも一つの切刃を備えた切削部とこの切削部の後端側に連なるとともに後端側に向かうにしたがい外径が漸次縮径する略円錐台状のテーパ部とを有する刃部が、工具本体の先端面に穿設されて後端側に向かうにしたがい内径が漸次縮径する略円錐台孔状のテーパ孔を有する取付孔に挿入されるとともに、前記刃部が前記工具本体の軸線方向の後端側に引き込まれることにより、前記刃部のテーパ部の外周面が前記取付孔のテーパ孔の内周面を押圧して、前記刃部が着脱可能に装着される刃部交換式切削工具であって、前記工具本体の先端面とこの先端面に対向して配置される前記刃部の壁面との間に、これら先端面及び壁面に密着して前記刃部を周回する、ヤング率が６０〜２２０ＧＰａの範囲に設定された弾性体のリング部材が介在させられていて、前記リング部材と前記刃部の壁面との密着面が後端側に向かうにしたがい径が漸次縮径するテーパ状に形成されるとともに前記リング部材と前記工具本体の先端面との密着面が前記工具本体の軸線に直交するように延在されていること、前記リング部材と前記工具本体の先端面との密着面が後端側に向かうにしたがい径が漸次拡径するテーパ状に形成されるとともに前記リング部材と前記刃部の壁面との密着面が前記工具本体の軸線に直交するように延在されていること、及び、前記リング部材と前記刃部の壁面との密着面が後端側に向かうにしたがい径が漸次縮径するテーパ状に形成されるとともに前記リング部材と前記工具本体の先端面との密着面が後端側に向かうにしたがい径が漸次拡径するテーパ状に形成されていることのうちのいずれか一つを満足しており、前記刃部が前記工具本体の軸線方向の後端側に引き込まれることにより、前記リング部材が径方向外方側に向かって押し広げられるように弾性変形して拡径させられることを特徴とするものである。
このような本発明によれば、工具本体の先端面とこれに対向する刃部の壁面との間に、これら先端面及び壁面に密着するようにして、弾性体からなるリング部材が介在させられていることから、刃部を取付孔内で軸線方向の後端側に引き込むときには、リング部材の存在によって、この刃部が取付孔の奥深くまで入り過ぎるのを防止することが可能となり、刃部の取り外しができなくなってしまうことがない。
しかも、この弾性体からなるリング部材は、工具本体の先端面に対する密着面及び刃部の壁面に対する密着面のうちの少なくとも一方が上記のように傾斜したテーパ状とされていることから、刃部が軸線方向の後端側に引き込まれたときに、このリング部材が弾性変形して拡径させられることになるので、刃部の壁面とリング部材とを密着させつつも、刃部のテーパ部の外周面と取付孔のテーパ孔の内周面とを確実に密着させることが可能となる。これにより、加工精度に多少の誤差が生じていたとしても、刃部を確実に２面拘束することが可能となるので、刃部の取付剛性を容易かつ確実に高めることができる。
さらには、このようなリング部材が存在することによって、工具本体の先端面と刃部の壁面との間の隙間に、塵などの異物が入ることを防止できるので、刃部の着脱を繰り返したとしても、刃部のテーパ部の外周面と取付孔のテーパ孔の内周面との間に異物が侵入する危険性を低減することができる。
【０００９】
ここで、前記密着面における片角でのテーパ角度は、１０〜８０゜の範囲に設定されていることが好ましく、このテーパ角度が１０゜より小さくなると、軸線方向に沿った押圧力を得られにくくなって、刃部を２面拘束させることによってその取付剛性を高める効果が薄れてしまうおそれがあり、一方、テーパ角度が８０゜より大きくなると、密着面に生じる摩擦が大きくなりすぎて、リング部材が拡径しにくくなってしまうおそれがある。
【００１１】
【発明の実施の形態】
以下、本発明の実施形態を添付した図面を参照しながら説明する。
図１（ａ）は本実施形態による刃部交換式切削工具の一部破断側面図、（ｂ）は（ａ）における要部拡大図である。
本実施形態による刃部交換式切削工具１０は、図１に示すように、軸線Ｏ回りに回転させられる工具本体１１と、この工具本体１１に着脱自在に装着されて固定される刃部２０と、刃部２０を軸線Ｏ方向の後端側に引き込むために用いられる引込部材としてのボルト部３０と、リング部材４０とからなるものである。
【００１２】
工具本体１１は、例えばスチール等によって、軸線Ｏを中心とする略円柱状に形成されており、その軸線Ｏ方向の先端側を向いて軸線Ｏに直交するように延在する先端面１２に、軸線Ｏ方向の後端側に向けて軸線Ｏを中心とした取付孔１３が穿設されていることにより、先端面１２が略リング形状をなすようになっている。
また、取付孔１３は、工具本体１１の先端面１２から後端側に向かって内径が一定の勾配で漸次縮径していく略円錐台孔状のテーパ孔１４と、このテーパ孔１４の後端側に連なるとともに、一定の内径で後端側に向かって延びる略円柱孔状の収納孔１５と、この収納孔１５の後端側に連なる雌ねじ部１６とから構成されている。
【００１３】
刃部２０は、例えば超硬合金からなり、少なくとも一つの切刃が最先端に形成された切削部２１と、この切削部２１の後端側に連なるとともに後端側に向かうにしたがい外径が一定の勾配で漸次縮径していく略円錐台状をなすテーパ部２２と、このテーパ部２２の後端側に連なる後端側部分２３とから構成されて、軸線Ｏを中心として形成されている。
刃部２０の後端側部分２３は、テーパ部２２の後端側に段差部を経て連なる軸部２５と、この軸部２５の後端側に連なるとともに刃部２０の後端部をなし、かつ、軸部２５の外周面よりも径方向外方側に一段突出する角部２７を備えた端部２６とからなるフック部２４とされている。
【００１４】
また、刃部２０において、切削部２１とテーパ部２２との接続部分は、切削部２１の後端側及びテーパ部２２の先端側に連なるとともに後端側に向かうにしたがい外径が一定の勾配で漸次縮径していく略円錐台状をなす副テーパ部２８となっている。
ここで、テーパ部２２における片角でのテーパ角度α（軸線Ｏを含む断面で見たときにテーパ部２２が軸線Ｏとなす狭角）は、２〜２５゜の範囲に設定されているのに対し、副テーパ部２４における片角でのテーパ角度β（軸線Ｏを含む断面で見たときに副テーパ部２４が軸線Ｏとなす狭角）は、１０〜８０゜の範囲内で上記のテーパ角度αよりも大きくなる（α＜β）ように設定されている。
【００１５】
ボルト部３０は、例えばスチールからなり、略円柱状をなす先端側部分３１と、この先端側部分３１の後端側に連なる雄ねじ部３２ａとから構成されて、軸線Ｏを中心として形成されている。
ボルト部３０の先端側部分３１には、その端面（ボルト部３０における先端面）に開口するフック穴３２ｂが形成されているとともに、このフック穴３２ｂの後端側と連通するように、軸線Ｏを中心とした一定の内径を有する略円柱孔状をなすフック部収納孔３３が形成されている。
【００１６】
フック穴３２ｂは、刃部２０におけるフック部２４の端部２６及び軸部２５がちょうど通過可能な大きさに設定されており、このフック穴３２ｂの周囲に位置してフック部収納孔３３の内周面から屹立する軸線Ｏ方向の後端側を向く壁面には、軸線Ｏ方向の先端側に一段凹むように、上記のフック部２４の端部２６の角部２７を嵌合可能な嵌合部３４が形成されている。
また、ボルト部３０には、押圧体３６とバネ３７とから構成された押圧部材３５が設けられており、押圧体３６がバネ３７によって軸線Ｏ方向の先端側へ向かって付勢されている。
【００１７】
ここで、刃部２０及びボルト部３０については、フック部２４の端部２６をフック穴３２ｂに挿入して通過させてから、刃部２０をボルト部３０に対して周方向に所定角度相対回転させた後、刃部２０とボルト部３０とを軸線Ｏ方向で互いに離間する方向へ相対移動させることによって、フック部２４の端部２６の角部２７がフック穴３２ｂの周囲の壁面に形成された嵌合部３４に嵌合させられた状態となっており、これら刃部２０とボルト部３０との周方向での相対回転及び軸線Ｏ方向で互いに離間する方向への相対移動が阻止されて、刃部２０とボルト部３０とが互いに連結されている。
なお、刃部２０とボルト部３０とが互いに連結された状態では、ボルト部３０に設けられた押圧部材３５によって、これら刃部２０とボルト部３０とが軸線Ｏ方向で互いに離間する方向へ押圧されているので、刃部２０とボルト部３０との連結が容易に外れないようになっている。
【００１８】
互いに連結された刃部２０及びボルト部３０は、工具本体１１の先端面１２に穿設された取付孔１３に対し、刃部２０のテーパ部２２が取付孔１３のテーパ孔１４内に収容され、刃部２０の後端側部分２３（フック部２４）とボルト部３０の先端側部分３１とが取付孔１３の収納孔１５内に収容されるように挿入されており、ボルト部３０の雄ねじ部３２ａが、取付孔１３の雌ねじ部１６にねじ込まれている。
【００１９】
ここで、刃部２０には、切削部２１とテーパ部２２とを接続する副テーパ部２８が形成されていて、しかも、副テーパ部２８における片角でのテーパ角度βが、テーパ部２２における片角でのテーパ角度αよりも大きくなっていることから、この副テーパ部２８の外周面（刃部２０の壁面）が工具本体１１の先端面１２に対向して配置されている。
【００２０】
また、互いに対向しあう刃部２０の副テーパ部２８の外周面と工具本体１１の先端面１２との間には、刃部２０を周回するようにして、リング部材４０が介在させられている。
このリング部材４０は、ヤング率が６０〜２２０ＧＰａの範囲に設定された弾性体であって、具体的には、例えばアルミや鋼から構成されたものであり、全周に亘って切れ目なく連なるように構成されている。
【００２１】
リング部材４０における略リング形状をなす一対の端面４１，４２のうち、軸線Ｏ方向の後端側に向けられた一方の端面４１は、工具本体１１の先端面１２に対応するように、軸線Ｏ方向に直交するように延在させられ、軸線Ｏ方向の先端側に向けられた他方の端面４２は、刃部２０の副テーパ部２８の形状に対応するように、軸線Ｏ方向の後端側（一方の端面４１側）に向かうにしたがい内径が漸次縮径していくようなテーパ面４３を有している（テーパ面４３における片角でのテーパ角度が、副テーパ部２８における片角でのテーパ角度βと略一致している）。
【００２２】
そして、ボルト部３０の雄ねじ部３２ａが取付孔１３の雌ねじ部１６にねじ込まれていることで、このボルト部３０が取付孔１３内で軸線Ｏ方向の後端側に引き込まれているとともに、ボルト部３０の先端側部分３１と連結された後端側部分２３を有する刃部２０が、取付孔１３内で軸線Ｏ方向の後端側に引き込まれている。
【００２３】
これにより、刃部２０のテーパ部２２の外周面と取付孔１３のテーパ孔１４の内周面とが密着し、刃部２０の副テーパ部２８の外周面とリング部材４０の他方の端面４２に形成されたテーパ面４３とが密着し、さらに、リング部材４０の一方の端面４１と工具本体１１の先端面１２とが密着している状態となっている。そのため、刃部２０におけるテーパ部２２及び副テーパ部２８の外周面が、取付孔１３におけるテーパ孔１４の内周面及びリング部材４０における他方の端面に形成されたテーパ面４３をそれぞれ押圧することとなって、刃部２０の軸線Ｏと工具本体１１の軸線Ｏとが一致させられて心出しが行われ、刃部２０が工具本体１１に着脱自在に装着されて固定されている。
【００２４】
このような構成とされた刃部交換式切削工具１０において、刃部２０を工具本体１１に装着する際には、互いに連結された刃部２０及びボルト部３０を取付孔１３内に挿入してから、刃部２０を回転させることにより、この刃部２０と連結されたボルト部３０を回転させて、ボルト部３０の雄ねじ部３２ａを取付孔１３の雌ねじ部１６にねじ込み、刃部２０を軸線Ｏ方向の後端側に引き込んでいくことになる。
【００２５】
このとき、刃部２０の副テーパ部２８の外周面と工具本体１１の先端面１２との間にリング部材４０が介在させられていることから、刃部２０のテーパ部２２の外周面と取付孔１３のテーパ孔１４の内周面とが接触するよりも前に、刃部２０の副テーパ部２８の外周面とリング部材４０の一方の端面４２に形成されたテーパ面４３とが接触する。
【００２６】
このまま、刃部２０を回転させて、刃部２０を軸線Ｏ方向の後端側に引き込み続けていくと、弾性体であるリング部材４０における一方の端面４１と工具本体１１の先端面１２とが密着させられて、軸線Ｏに直交するように延在する密着面ができるとともに、リング部材４０における他方の端面４２に形成されたテーパ面４３と刃部２０の副テーパ部２８の外周面とが密着させられて、軸線Ｏ方向の後端側に向かうにしたがい径が漸次縮径するテーパ状の密着面（片角でのテーパ角度β）ができる。
【００２７】
これら２つの密着面のうち、リング部材４０における他方の端面４２に形成されたテーパ面４３と刃部２０の副テーパ部２８の外周面との密着面は、軸線Ｏ方向の後端側に向かうにしたがい径が漸次縮径するテーパ状をなしているので、刃部２０が軸線Ｏ方向の後端側へ引き込まれていくのにともない、弾性体であるリング部材４０がそのテーパ面４３に受ける押圧力によって径方向外方側に向かって押し広げられるように弾性変形して拡径させられる。
そのため、刃部２０の副テーパ部２８の外周面とリング部材４０の他方の端面４２に形成されたテーパ面４３との密着した状態を維持しつつ、このリング部材４０が弾性変形して拡径する分だけ刃部２０を軸線Ｏ方向の後端側にさらに引き込むことが可能となり、ついには、刃部２０のテーパ部２２の外周面と取付孔１３のテーパ孔１４の内周面とが密着させられる。
【００２８】
これにより、刃部２０におけるテーパ部２２の外周面及び副テーパ部２８の外周面が、取付孔１３のテーパ孔１４の内周面及びリング部材４０における他方の端面４２に形成されたテーパ面４３をそれぞれ押圧した状態となって、刃部２０が工具本体１１に対して２面拘束で装着されるのである。
【００２９】
以上説明したような本実施形態によれば、工具本体１１の先端面１２とこれに対向する刃部の壁面（刃部２０の副テーパ部２８の外周面）との間に、これら先端面１２及び副テーパ部２８の外周面に密着するような弾性体からなるリング部材４０が介在させられているため、刃部２０を取付孔１３内で軸線Ｏ方向の後端側に引き込むとき、作業者が刃部２０を回転させるために与えた締め付けトルクが大きすぎたとしても、このリング部材４０の存在によって、刃部２０が取付孔１３内の奥深くまで入り過ぎることを防止でき、刃部２０の取り外しができなくなるといった不具合が生じることがない。
【００３０】
また、この弾性体からなるリング部材４０における他方の端面４２に形成されたテーパ面４３と刃部２０における副テーパ部２８の外周面との密着面が、軸線Ｏ方向の後端側に向かうにしたがい径が漸次縮径するテーパ状となっているため、刃部２０が軸線Ｏ方向の後端側に引き込まれたときには、このリング部材４０が弾性変形して拡径させられる。
このリング部材４０が弾性変形する分だけ、刃部２０における軸線Ｏ方向での移動の自由度が増すことになり、刃部２０における副テーパ部２８の外周面とリング部材４０における他方の端面４２に形成されたテーパ面４３とを密着させた状態を維持しつつ、これと同時に、刃部２０のテーパ部２２の外周面と取付孔１３のテーパ孔１４の内周面とを確実に密着させることができる。
これにより、加工精度の多少の誤差を吸収することができるので、容易かつ確実に、刃部２０の２面拘束を実現することが可能となり、刃部２０の取付剛性を高めて、切削加工中においてもビビリ振動を生じさせることがない。
【００３１】
さらに、このようなリング部材４０を用いたことによって、工具本体１１の先端面１２とこの先端面１２に対向して配置される副テーパ部２８の外周面との間の隙間に、塵などの異物が入ってしまう事態を防止することができるので、刃部２０の着脱を繰り返し行ったとしても、刃部２０のテーパ部２２の外周面と取付孔１３のテーパ孔１４の内周面との間に異物が侵入する危険性を低減して、刃部２０の装着状態を安定して維持し続けることができる。
【００３２】
ここで、弾性体であるリング部材４０のヤング率が６０〜２２０ＧＰａの範囲に設定されていることによって、刃部２０の取付剛性を高めるために必要な軸線Ｏ方向に沿う押圧力を適度に生じさせ、かつ、加工精度の誤差を吸収するために必要な弾性変形を適度に生じさせることができている。
このヤング率が６０ＧＰａより小さくなってしまうと、軸線Ｏ方向に沿う押圧力が必要十分に得られず、取付剛性を高めることができなくなってしまうおそれがあり、一方、ヤング率が２２０ＧＰａより大きくなると、リング部材４０の弾性変形が必要十分に望めなくなってしまうおそれがある。
なお、上述のような効果をより確実なものとするためには、リング部材４０のヤング率は、７０〜１３０ＧＰａの範囲に設定されていることが好ましい。
【００３３】
また、ここで、リング部材４０における他方の端面４２に形成されたテーパ面４３と刃部２０における副テーパ部２８の外周面との密着面について、その片角でのテーパ角度βが、１０〜８０゜の範囲に設定されていることによって、刃部２０の取付剛性を高めるために必要な軸線Ｏ方向に沿う押圧力を十分に確保することができ、かつ、加工精度の誤差を吸収するために必要なリング部材４０の弾性変形を十分に生じさせることができている。
このテーパ角度βが１０゜より小さくなると、軸線Ｏ方向に沿った押圧力を得られにくくなって、刃部２０を２面拘束させることによってその取付剛性を高める効果が薄れてしまうおそれがあり、一方、テーパ角度βが８０゜より大きくなると、このテーパ状の密着面に生じる摩擦が大きくなりすぎて、リング部材４０の弾性変形による拡径が生じにくくなってしまうおそれがある。
なお、上述のような効果をより確実なものとするためには、テーパ角度βは、３０〜６０゜の範囲に設定されていることが好ましい。
【００３４】
以上の実施形態においては、リング部材４０（他方の端面４２に形成されたテーパ面４３）と刃部２０の壁面（副テーパ部２４の外周面）との密着面を、軸線Ｏ方向の後端側に向かうにしたがい径が漸次縮径するテーパ状にしているが、これに限定されることはない。例えば、リング部材４０と工具本体１１の先端面１２との密着面を、軸線Ｏ方向の後端側に向かうにしたがい径が漸次拡径するテーパ状にしても、上述のような効果を得ることができ、また、リング部材４０と工具本体１１の先端面１２との密着面及びリング部材４０と刃部２０の壁面との密着面の両方をテーパ状にしてもよい。
さらに、リング部材４０としては、全周に亘って切れ目なく連なるように構成されたものに限らず、一つの切れ目を有する略Ｃ字型をなすようなものを用いることも考えられる。
【００３５】
また、以上説明してきたような刃部交換式切削工具については、工具本体の後端側部分が工作機械の回転軸に取り付けられることによって、この工具本体が軸線回りに回転させられるものに限定されることはなく、例えば、工作機械の回転軸が工具本体をなしている、つまり、工作機械の回転軸における先端面に上述したような取付孔が穿設されていて、この取付孔に対して刃部が装着されるようなものでも構わない（工具本体を、工作機械の回転軸を含んだ表現とする）。
【００３６】
【発明の効果】
本発明によれば、刃部を取付孔内で軸線方向の後端側に引き込むときには、工具本体の先端面とこれに対向する刃部の壁面との間に介在させられるリング部材によって、この刃部が取付孔の奥深くまで入り過ぎてしまうのを防止することが可能となり、刃部を工具本体から取り外すことができなくなってしまうことがない。
また、弾性体からなるリング部材の、工具本体の先端面に対する密着面及び刃部の壁面に対する密着面のうちの少なくとも一方がテーパ状とされていることによって、刃部が軸線方向の後端側に引き込まれたときに、このリング部材が弾性変形して拡径させられるので、刃部の壁面とリング部材とを密着させつつも、刃部のテーパ部の外周面と取付孔のテーパ孔の内周面とを確実に密着させることができる。これにより、加工精度に多少の誤差が生じていたとしても、刃部を確実に２面拘束することが可能となるので、刃部の取付剛性を容易に高めることができて、切削加工時にビビリ振動を生じさせてしまうことがない。
さらに、リング部材を用いることによって、工具本体の先端面と刃部の壁面との間の隙間に、塵などの異物が入ることを防止できるので、刃部の着脱を繰り返したとしても、刃部のテーパ部の外周面と取付孔のテーパ孔の内周面との間に異物が侵入する危険性を低減して、刃部の装着状態を安定して維持することができる。
【図面の簡単な説明】
【図１】（ａ）は本実施形態による刃部交換式切削工具の一部破断側面図、（ｂ）は（ａ）における要部拡大図である。
【図２】従来の刃部交換式切削工具の一例を示す一部破断側面図である。
【符号の説明】
１０刃部交換式切削工具
１１工具本体
１２先端面
１３取付孔
１４テーパ孔
２０刃部
２１切削部
２２テーパ部
２８副テーパ部
４０リング部材
Ｏ軸線[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blade part exchangeable cutting tool in which a blade part is detachably attached to a tool body.
[0002]
[Prior art]
Conventionally, as an example of this kind of blade part exchange-type cutting tool, there is one disclosed in Japanese Patent No. 2656949.
As shown in FIG. 2, the tool body 2 of such a blade part replaceable cutting tool 1 is provided with a mounting hole 3 on the front end surface 2A toward the rear end side in the axis O direction, The mounting hole 3 has a generally frustoconical tapered hole 3A that opens to the front end surface 2A and gradually decreases in diameter as it goes to the rear end side, and a female screw portion 3B that continues to the rear end side of the tapered hole 3A. It is composed of
Moreover, it has the cutting part 4A provided with at least one cutting edge, and the substantially truncated-cone-shaped taper part 4B which continues to the rear end side of this cutting part 4A, and whose outer diameter is gradually reduced toward the rear end side. The hook part 4C formed at the rear end of the blade part 4 and the hook part 5A formed at the front end of the bolt part 5 having the male screw part 5B are detachably connected, and the connected blade part 4 and bolt part. 5 is inserted into the mounting hole 3 of the tool body 2.
[0003]
Then, as the male threaded part 5B of the bolt part 5 is screwed into the female threaded part 3B of the mounting hole 3, the bolt part 5 is pulled into the rear end side in the axis O direction of the tool body 2 and this bolt part. The blade portion 4 connected to 5 is also drawn to the rear end side in the direction of the axis O, and the outer peripheral surface of the tapered portion 4B of the blade portion 4 presses the inner peripheral surface of the tapered hole 3A of the mounting hole 3. The blade portion 4 is detachably attached to the tool body 2.
In the state where the blade portion 4 is mounted on the tool body 2, the tip surface 2A of the tool body 2, the cutting portion 4A and the taper portion 4B of the blade portion 4 are disposed while facing the tip surface 2A. A gap is formed between the wall surfaces 4D facing the rear end side in the direction of the axis O to be connected without being in close contact therewith.
[0004]
[Problems to be solved by the invention]
In the blade part replaceable cutting tool 1 as described above, when the operator rotates the blade part 4, the bolt part 5 connected to the blade part 4 is rotated and the male thread part 5B of the bolt part 5 is attached. The screw 3 is screwed into the female screw portion 3B of the hole 3, and the bolt portion 5 and the blade portion 4 are drawn toward the rear end side in the direction of the axis O. The tightening torque applied to rotate the blade portion 4 at this time Changes drastically with the power of the operator.
If the operator puts too much force, the blade 4 will enter too deeply into the mounting hole 3, and the pressing force generated between the outer peripheral surface of the tapered portion 4B and the inner peripheral surface of the tapered hole 3A (due to the wedge effect) ) It becomes very high, and there is a possibility that the blade part 4 cannot be removed from the tool body 2.
Furthermore, when the workpiece is cut, the attachment hole 3 is generated by the thermal expansion of the tool body 2 made of, for example, steel due to the generation of cutting heat or the centrifugal force generated when the tool body 2 rotates at a high speed. The taper hole 3A may swell, and even in such a case, the blade part 4 may enter too deeply into the attachment hole 3 and the blade part 4 may not be removed.
[0005]
Further, in the blade part replaceable cutting tool 1 as described above, when the blade part 4 is mounted on the tool body 2, the outer peripheral surface of the taper part 4 </ b> B of the blade part 4 and the inner periphery of the taper hole 3 </ b> A of the attachment hole 3. Since the blade portion 4 is restrained only by closely contacting the surface, the mounting rigidity of the blade portion 4 tends to be insufficient, and chatter vibration may occur during cutting.
In order to solve this, the outer peripheral surface of the taper portion 4B and the inner peripheral surface of the taper hole 3A are brought into close contact with each other, and at the same time, the tip surface 2A of the tool body 2 and the blade portion 4 disposed to face the tip surface 2A. It is conceivable to use a so-called two-surface constraint such as close contact with the wall surface 4D. To achieve such a two-surface constraint of the blade portion 4, the outer peripheral surface of the taper portion 4B and the inside of the taper hole 3A are considered. Since the peripheral surface and the tip surface 2A of the tool body 2 and the wall surface 4D of the blade portion 4 need to be machined with high accuracy, they could not be effective solving means.
[0006]
Here, when the taper portion 4B of the blade portion 4 is hollow, and the outer peripheral surface of the taper portion 4B of the blade portion 4 presses the inner peripheral surface of the taper hole 3A of the mounting hole 3, the taper portion of the blade portion 4 Although a method of elastically deforming the outer diameter of 4B so as to reduce the diameter and absorbing the above-described error in machining accuracy to realize the two-surface constraint is also conceivable, it is used for such a blade-exchangeable cutting tool 1. As the material constituting the blade portion 4, a super hard substance (super hard alloy, cermet, ceramic, etc.) is used, so it is difficult to make the tapered portion 4B hollow from the viewpoint of processing, and the outer diameter When the tool becomes small (for example, 20 mm or less) and has a small diameter, a problem of strength reduction also occurs.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a blade part replaceable cutting tool and a ring that can easily increase the attachment rigidity of the blade part without causing problems in attaching and detaching the blade part to the tool body. An object is to provide a member.
[0008]
[Means for Solving the Problems]
  In order to solve the above-described problems and achieve such an object, the blade part replaceable cutting tool according to the present invention is connected to a cutting part having at least one cutting edge and a rear end side of the cutting part. A blade portion having a substantially frustoconical taper portion whose outer diameter gradually decreases as it goes toward the rear end side is formed in the tip surface of the tool body, and the inner diameter gradually decreases toward the rear end side. And the outer peripheral surface of the tapered portion of the blade portion is inserted into the attachment hole having the tapered hole having a substantially frustoconical hole shape, and the blade portion is pulled toward the rear end side in the axial direction of the tool body. A blade part replaceable cutting tool in which the blade part is detachably mounted by pressing the inner peripheral surface of the taper hole of the mounting hole, and is disposed facing the tip surface of the tool body and the tip surface. The front edge surface and the wall surface are in close contact with the wall surface of the blade portion. Orbiting the blade portion, Young's modulus was set in the range of 60-220 GPaAn elastic ring member is interposed, and a close contact surface between the ring member and the wall surface of the blade portion is formed in a tapered shape with a diameter gradually decreasing toward the rear end side.And the contact surface between the ring member and the tip end surface of the tool body extends so as to be orthogonal to the axis of the tool body.is being done,The contact surface between the ring member and the front end surface of the tool body is formed in a taper shape in which the diameter gradually expands toward the rear end side.The contact surface between the ring member and the wall surface of the blade portion is extended so as to be orthogonal to the axis of the tool body, and the contact surface between the ring member and the wall surface of the blade portion is A tapered shape in which the diameter gradually decreases with increasing diameter toward the rear end side, and the contact surface between the ring member and the front end surface of the tool body gradually increases in diameter toward the rear end side. Formed intoOf what has beenAny oneSatisfiedIn addition, when the blade portion is pulled toward the rear end side in the axial direction of the tool body, the ring member is elastically deformed and expanded in diameter so as to be pushed and expanded toward the radially outward side.It is characterized by.
  According to the present invention, the ring member made of an elastic body is interposed between the tip surface of the tool body and the wall surface of the blade portion facing the tool body so as to be in close contact with the tip surface and the wall surface. Therefore, when the blade portion is pulled to the rear end side in the axial direction in the mounting hole, it is possible to prevent the blade portion from entering too deeply into the mounting hole due to the presence of the ring member. It will not be impossible to remove.
  Moreover, since the ring member made of this elastic body has a tapered shape in which at least one of the contact surface to the tip surface of the tool body and the contact surface to the wall surface of the blade portion is inclined as described above, Since the ring member is elastically deformed and expanded in diameter when is pulled to the rear end side in the axial direction, the taper portion of the blade portion is brought into close contact with the wall surface of the blade portion and the ring member. The outer peripheral surface of the mounting hole and the inner peripheral surface of the taper hole of the mounting hole can be securely adhered to each other. As a result, even if some errors occur in the machining accuracy, the blade portion can be reliably restrained on two surfaces, so that the attachment rigidity of the blade portion can be easily and reliably increased.
  Furthermore, since the presence of such a ring member can prevent foreign matters such as dust from entering the gap between the tip surface of the tool body and the wall surface of the blade portion, the attachment and detachment of the blade portion was repeated. Even so, it is possible to reduce the risk of foreign matter entering between the outer peripheral surface of the tapered portion of the blade portion and the inner peripheral surface of the tapered hole of the mounting hole.
[0009]
Here, the taper angle at one angle on the contact surface is preferably set in a range of 10 to 80 °. When the taper angle is smaller than 10 °, a pressing force along the axial direction can be obtained. If the taper angle is larger than 80 °, the friction generated on the contact surface becomes too large and the ring becomes too difficult. There is a possibility that the member is difficult to expand the diameter.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
Fig.1 (a) is a partially broken side view of the blade part exchange-type cutting tool by this embodiment, (b) is the principal part enlarged view in (a).
As shown in FIG. 1, the blade part replaceable cutting tool 10 according to the present embodiment includes a tool body 11 that is rotated around an axis O, and a blade part 20 that is detachably attached to the tool body 11 and fixed. , And a ring member 40 and a bolt part 30 as a drawing member used for drawing the blade part 20 toward the rear end side in the direction of the axis O.
[0012]
The tool body 11 is formed in a substantially cylindrical shape centered on the axis O, for example, of steel or the like, and faces the tip side in the direction of the axis O and extends to the tip surface 12 extending perpendicularly to the axis O. By attaching the attachment hole 13 centering on the axis O toward the rear end side in the direction of the axis O, the front end surface 12 has a substantially ring shape.
The mounting hole 13 includes a tapered hole 14 having a substantially truncated cone shape in which the inner diameter gradually decreases with a constant gradient from the front end surface 12 to the rear end side of the tool body 11, and a rear end of the tapered hole 14. The housing hole 15 has a substantially cylindrical hole shape that extends toward the rear end side with a constant inner diameter and is connected to the end side, and a female screw portion 16 that is continuous to the rear end side of the storage hole 15.
[0013]
The blade portion 20 is made of, for example, a cemented carbide, and has a cutting portion 21 in which at least one cutting edge is formed at the foremost end, and the outer diameter of the cutting portion 21 is continuous with the rear end side and toward the rear end side. A tapered portion 22 having a substantially truncated cone shape that gradually decreases in diameter with a constant gradient and a rear end side portion 23 that continues to the rear end side of the tapered portion 22 are formed around an axis O. Yes.
The rear end side portion 23 of the blade part 20 is connected to the rear end side of the taper part 22 through a step part, and is connected to the rear end side of the shaft part 25 and constitutes the rear end part of the blade part 20. In addition, the hook portion 24 includes an end portion 26 having a corner portion 27 that protrudes one step radially outward from the outer peripheral surface of the shaft portion 25.
[0014]
Moreover, in the blade part 20, the connection part of the cutting part 21 and the taper part 22 continues to the rear end side of the cutting part 21 and the front end side of the taper part 22, and has a constant outer diameter toward the rear end side. The sub taper portion 28 forms a substantially truncated cone shape that gradually decreases in diameter.
Here, the taper angle α at one angle in the taper portion 22 (the narrow angle formed by the taper portion 22 and the axis O when viewed in a cross section including the axis O) is set in the range of 2 to 25 °. On the other hand, the taper angle β at one angle of the sub taper portion 24 (the narrow angle that the sub taper portion 24 forms with the axis O when viewed in a cross section including the axis O) is within the range of 10 to 80 °. The taper angle α is set to be larger (α <β).
[0015]
  The bolt portion 30 is made of, for example, steel, and has a substantially cylindrical tip side portion 31 and a male screw portion continuous to the rear end side of the tip side portion 31.32aAnd is formed around the axis O.
  The front end portion 31 of the bolt part 30 has a hook hole that opens to the end face (the front end face of the bolt part 30).32bThis hook hole is formed with32bA hook housing hole 33 having a substantially cylindrical hole shape having a constant inner diameter around the axis O is formed so as to communicate with the rear end side.
[0016]
  Hook hole32bIs set to a size that allows the end portion 26 and the shaft portion 25 of the hook portion 24 of the blade portion 20 to pass through.32bThe end of the hook portion 24 is formed so as to be recessed one step toward the front end side in the axis O direction on the wall surface facing the rear end side in the axis O direction and standing around the inner peripheral surface of the hook portion receiving hole 33. The fitting part 34 which can fit the corner | angular part 27 of the part 26 is formed.
  The bolt portion 30 is provided with a pressing member 35 composed of a pressing body 36 and a spring 37, and the pressing body 36 is urged toward the tip end side in the axis O direction by the spring 37.
[0017]
  Here, for the blade part 20 and the bolt part 30, the end part 26 of the hook part 24 is hooked to the hook hole.32bAfter the blade portion 20 is inserted and passed, the blade portion 20 is rotated relative to the bolt portion 30 by a predetermined angle in the circumferential direction, and then the blade portion 20 and the bolt portion 30 are relatively moved away from each other in the axis O direction. By doing so, the corner 27 of the end 26 of the hook 24 is32bIn a direction in which the blade portion 20 and the bolt portion 30 are relatively rotated in the circumferential direction and separated from each other in the axis O direction. The relative movement is prevented, and the blade part 20 and the bolt part 30 are connected to each other.
  In the state where the blade part 20 and the bolt part 30 are connected to each other, the pressing member 35 provided on the bolt part 30 causes the blade part 20 and the bolt part 30 to be pressed away from each other in the direction of the axis O. Therefore, the connection between the blade part 20 and the bolt part 30 is not easily removed.
[0018]
  The blade portion 20 and the bolt portion 30 that are connected to each other have the taper portion 22 of the blade portion 20 accommodated in the taper hole 14 of the attachment hole 13 with respect to the attachment hole 13 formed in the distal end surface 12 of the tool body 11. The rear end side portion 23 (hook portion 24) of the blade portion 20 and the front end side portion 31 of the bolt portion 30 are inserted so as to be accommodated in the accommodating hole 15 of the mounting hole 13, and the male screw of the bolt portion 30 Part32aIs screwed into the female thread portion 16 of the mounting hole 13.
[0019]
Here, the blade portion 20 is formed with a sub-taper portion 28 that connects the cutting portion 21 and the taper portion 22, and the taper angle β at one angle of the sub-taper portion 28 is equal to the taper portion 22. Since it is larger than the taper angle α at one angle, the outer peripheral surface (the wall surface of the blade portion 20) of the sub-taper portion 28 is disposed to face the tip surface 12 of the tool body 11.
[0020]
Further, a ring member 40 is interposed between the outer peripheral surface of the sub taper portion 28 of the blade portion 20 facing each other and the tip surface 12 of the tool body 11 so as to go around the blade portion 20. .
The ring member 40 is an elastic body whose Young's modulus is set in a range of 60 to 220 GPa, and specifically, is made of, for example, aluminum or steel, and is continuously connected over the entire circumference. It is configured.
[0021]
Of the pair of end faces 41, 42 having a substantially ring shape in the ring member 40, one end face 41 directed toward the rear end side in the axis O direction corresponds to the tip end face 12 of the tool body 11. The other end face 42 that is extended so as to be orthogonal to the direction and directed toward the front end side in the axis O direction corresponds to the shape of the sub taper portion 28 of the blade portion 20, and is on the rear end side in the axis O direction. The taper surface 43 has an inner diameter that gradually decreases toward the one end surface 41 side (the taper angle at one angle of the taper surface 43 is one angle at the sub-taper portion 28). Is substantially the same as the taper angle β.
[0022]
  And the male thread part of the bolt part 3032aIs screwed into the female threaded portion 16 of the mounting hole 13 so that the bolt portion 30 is pulled into the rear end side in the direction of the axis O in the mounting hole 13 and is connected to the front end side portion 31 of the bolt portion 30. The blade portion 20 having the rear end side portion 23 is drawn into the mounting hole 13 toward the rear end side in the axis O direction.
[0023]
Thereby, the outer peripheral surface of the taper portion 22 of the blade portion 20 and the inner peripheral surface of the taper hole 14 of the mounting hole 13 are in close contact, and the outer peripheral surface of the sub taper portion 28 of the blade portion 20 and the other end surface 42 of the ring member 40. The one end surface 41 of the ring member 40 and the tip end surface 12 of the tool body 11 are in close contact with each other. Therefore, the outer peripheral surfaces of the tapered portion 22 and the sub-tapered portion 28 in the blade portion 20 press the tapered surface 43 formed on the inner peripheral surface of the tapered hole 14 in the mounting hole 13 and the other end surface of the ring member 40, respectively. Thus, the axis O of the blade part 20 and the axis O of the tool body 11 are aligned to perform centering, and the blade part 20 is detachably attached to the tool body 11 and fixed.
[0024]
  In the blade part replaceable cutting tool 10 having such a configuration, when the blade part 20 is mounted on the tool body 11, the blade part 20 and the bolt part 30 connected to each other are inserted into the mounting hole 13. Then, by rotating the blade part 20, the bolt part 30 connected to the blade part 20 is rotated, and the male thread part of the bolt part 30 is rotated.32aIs screwed into the female threaded portion 16 of the mounting hole 13, and the blade portion 20 is pulled toward the rear end side in the axis O direction.
[0025]
At this time, since the ring member 40 is interposed between the outer peripheral surface of the sub taper portion 28 of the blade portion 20 and the tip surface 12 of the tool body 11, the outer peripheral surface of the taper portion 22 of the blade portion 20 is attached to the outer peripheral surface. Before the inner peripheral surface of the tapered hole 14 of the hole 13 contacts, the outer peripheral surface of the sub-tapered portion 28 of the blade portion 20 and the tapered surface 43 formed on one end surface 42 of the ring member 40 contact. .
[0026]
If the blade portion 20 is rotated and the blade portion 20 is continuously pulled toward the rear end side in the direction of the axis O, the one end surface 41 of the ring member 40 that is an elastic body and the front end surface 12 of the tool body 11 are connected. A close contact surface is formed that extends so as to be orthogonal to the axis O, and a tapered surface 43 formed on the other end surface 42 of the ring member 40 and an outer peripheral surface of the sub taper portion 28 of the blade portion 20 are formed. A taper-shaped close contact surface (taper angle β at one angle) is formed in which the diameter gradually decreases as it is brought into close contact with the rear end side in the axis O direction.
[0027]
Of these two contact surfaces, the contact surface between the tapered surface 43 formed on the other end surface 42 of the ring member 40 and the outer peripheral surface of the sub taper portion 28 of the blade portion 20 is directed toward the rear end side in the axis O direction. Accordingly, since the diameter gradually decreases, the ring member 40, which is an elastic body, receives the tapered surface 43 as the blade portion 20 is drawn toward the rear end side in the axis O direction. It is elastically deformed and expanded in diameter so as to be expanded outwardly in the radial direction by the pressing force.
Therefore, the ring member 40 is elastically deformed and expanded in diameter while maintaining a close contact state between the outer peripheral surface of the sub taper portion 28 of the blade portion 20 and the tapered surface 43 formed on the other end surface 42 of the ring member 40. Accordingly, the blade portion 20 can be further pulled toward the rear end side in the direction of the axis O. Finally, the outer peripheral surface of the tapered portion 22 of the blade portion 20 and the inner peripheral surface of the tapered hole 14 of the mounting hole 13 are in close contact with each other. Be made.
[0028]
Thereby, the outer peripheral surface of the taper part 22 and the outer peripheral surface of the sub taper part 28 in the blade part 20 are formed on the inner peripheral surface of the taper hole 14 of the attachment hole 13 and the other end face 42 of the ring member 40. The blade portion 20 is attached to the tool body 11 with two-face restraint.
[0029]
According to the present embodiment as described above, the front end surface 12 between the front end surface 12 of the tool main body 11 and the wall surface of the blade portion facing this (the outer peripheral surface of the sub taper portion 28 of the blade portion 20). Since the ring member 40 made of an elastic body that is in close contact with the outer peripheral surface of the sub taper portion 28 is interposed, when the blade portion 20 is pulled into the rear end side in the axis O direction in the mounting hole 13, the operator Even if the tightening torque applied to rotate the blade portion 20 is too large, the presence of the ring member 40 can prevent the blade portion 20 from entering too deeply into the mounting hole 13. There is no problem that it cannot be removed.
[0030]
Further, the contact surface between the tapered surface 43 formed on the other end surface 42 of the ring member 40 made of this elastic body and the outer peripheral surface of the sub-tapered portion 28 of the blade portion 20 is directed toward the rear end side in the axis O direction. Accordingly, since the diameter gradually becomes a tapered shape, the ring member 40 is elastically deformed and expanded in diameter when the blade portion 20 is drawn toward the rear end side in the axis O direction.
As the ring member 40 is elastically deformed, the degree of freedom of movement of the blade portion 20 in the direction of the axis O increases, and the outer peripheral surface of the sub taper portion 28 of the blade portion 20 and the other end surface 42 of the ring member 40. At the same time, the outer peripheral surface of the taper portion 22 of the blade portion 20 and the inner peripheral surface of the taper hole 14 of the mounting hole 13 are surely brought into close contact with each other while maintaining the state in which the taper surface 43 formed on be able to.
As a result, it is possible to absorb some errors in machining accuracy, so that it is possible to easily and surely realize the two-face constraint of the blade portion 20, and to increase the attachment rigidity of the blade portion 20 during cutting. No chatter vibration is generated even in
[0031]
Further, by using such a ring member 40, dust or the like can be found in the gap between the tip surface 12 of the tool body 11 and the outer peripheral surface of the sub taper portion 28 disposed to face the tip surface 12. Since it is possible to prevent foreign matter from entering, even if the blade portion 20 is repeatedly attached and detached, the outer peripheral surface of the tapered portion 22 of the blade portion 20 and the inner peripheral surface of the tapered hole 14 of the mounting hole 13 It is possible to reduce the risk of foreign matter intruding between them, and to maintain the mounting state of the blade portion 20 stably.
[0032]
Here, when the Young's modulus of the ring member 40 which is an elastic body is set in the range of 60 to 220 GPa, a pressing force along the axis O direction necessary for increasing the mounting rigidity of the blade portion 20 is appropriately generated. In addition, the elastic deformation necessary to absorb the error in processing accuracy can be appropriately generated.
If this Young's modulus is less than 60 GPa, a pressing force along the direction of the axis O cannot be obtained sufficiently and there is a risk that the mounting rigidity cannot be increased. On the other hand, if the Young's modulus is greater than 220 GPa. There is a risk that the elastic deformation of the ring member 40 may not be sufficiently necessary.
In addition, in order to make the above effects more reliable, the Young's modulus of the ring member 40 is preferably set in a range of 70 to 130 GPa.
[0033]
Here, the taper angle β at one angle of the contact surface between the taper surface 43 formed on the other end surface 42 of the ring member 40 and the outer peripheral surface of the sub taper portion 28 of the blade portion 20 is 10 to 10. By setting the angle within the range of 80 °, a sufficient pressing force along the direction of the axis O for increasing the mounting rigidity of the blade portion 20 can be secured, and an error in machining accuracy can be absorbed. The elastic deformation of the ring member 40 required for the above can be sufficiently generated.
If this taper angle β is smaller than 10 °, it is difficult to obtain a pressing force along the direction of the axis O, and there is a possibility that the effect of increasing the mounting rigidity by restraining the blade portion 20 on two sides may be reduced. On the other hand, when the taper angle β is larger than 80 °, the friction generated on the tapered contact surface becomes too large, and there is a possibility that the diameter expansion due to the elastic deformation of the ring member 40 is difficult to occur.
In order to make the above-described effect more reliable, the taper angle β is preferably set in the range of 30 to 60 °.
[0034]
In the above embodiment, the contact surface between the ring member 40 (the tapered surface 43 formed on the other end surface 42) and the wall surface of the blade portion 20 (the outer peripheral surface of the sub-taper portion 24) is used as the rear end in the axis O direction. The taper is such that the diameter gradually decreases as it goes to the side, but is not limited thereto. For example, even if the contact surface between the ring member 40 and the front end surface 12 of the tool body 11 is tapered such that the diameter gradually increases toward the rear end side in the axis O direction, the above-described effects can be obtained. In addition, both the contact surface between the ring member 40 and the tip surface 12 of the tool body 11 and the contact surface between the ring member 40 and the wall surface of the blade portion 20 may be tapered.
Furthermore, the ring member 40 is not limited to one that is continuously connected over the entire circumference, but it is also conceivable to use a substantially C-shaped member having one cut.
[0035]
In addition, the blade exchange type cutting tool as described above is limited to the tool body that is rotated around the axis by attaching the rear end portion of the tool body to the rotating shaft of the machine tool. For example, the rotating shaft of the machine tool forms the tool body, that is, the mounting hole as described above is formed in the tip surface of the rotating shaft of the machine tool. A blade may be mounted (the tool body is an expression including the rotation axis of the machine tool).
[0036]
【The invention's effect】
According to the present invention, when the blade portion is pulled into the rear end side in the axial direction within the mounting hole, the blade member is inserted by the ring member interposed between the tip surface of the tool body and the wall surface of the blade portion facing the blade body. It is possible to prevent the portion from entering too deeply into the mounting hole, and the blade portion cannot be removed from the tool body.
In addition, since at least one of the contact surface of the ring member made of an elastic body with respect to the front end surface of the tool body and the contact surface with respect to the wall surface of the blade portion is tapered, the blade portion is on the rear end side in the axial direction. Since the ring member is elastically deformed and expanded in diameter when drawn in, the outer peripheral surface of the taper portion of the blade portion and the taper hole of the attachment hole are brought into close contact with the wall surface of the blade portion and the ring member. The inner peripheral surface can be securely adhered. As a result, even if there is a slight error in machining accuracy, the blade portion can be reliably restrained on two surfaces, so that the attachment rigidity of the blade portion can be easily increased, and chattering is possible during cutting. There is no vibration.
Furthermore, by using a ring member, foreign matter such as dust can be prevented from entering the gap between the tip surface of the tool body and the wall surface of the blade portion. The risk of foreign matter entering between the outer peripheral surface of the taper portion and the inner peripheral surface of the taper hole of the mounting hole can be reduced, and the mounting state of the blade portion can be stably maintained.
[Brief description of the drawings]
FIG. 1 (a) is a partially broken side view of a blade-exchangeable cutting tool according to the present embodiment, and FIG. 1 (b) is an enlarged view of a main part in FIG.
FIG. 2 is a partially cutaway side view showing an example of a conventional blade replacement type cutting tool.
[Explanation of symbols]
10 Cutting tool with replaceable blade
11 Tool body
12 Tip surface
13 Mounting hole
14 Taper hole
20 blade
21 Cutting part
22 Taper
28 Secondary taper
40 Ring member
O axis

Claims

A blade portion having a cutting portion having at least one cutting edge and a substantially truncated cone-shaped taper portion whose outer diameter is gradually reduced toward the rear end side while continuing to the rear end side of the cutting portion is a tool. The blade portion is inserted into a mounting hole having a tapered hole having a substantially frustoconical hole shape whose inner diameter is gradually reduced as it is drilled in the front end surface of the main body and moves toward the rear end side, and the blade portion is in the axial direction of the tool main body The blade portion replaceable cutting is performed such that the outer peripheral surface of the tapered portion of the blade portion presses the inner peripheral surface of the tapered hole of the mounting hole by being pulled toward the rear end side, and the blade portion is detachably mounted. A tool,
Between the tip surface of the tool body and the wall surface of the blade portion arranged opposite to the tip surface, the Young's modulus is around 60 to 220 GPa, which circulates around the blade portion in close contact with the tip surface and the wall surface. An elastic ring member set in a range is interposed,
The close contact surface between the ring member and the wall surface of the blade portion is formed in a taper shape with a diameter gradually decreasing toward the rear end side, and the close contact surface between the ring member and the front end surface of the tool body is It extends so as to be orthogonal to the axis of the tool body, and the contact surface between the ring member and the tip surface of the tool body is formed in a tapered shape in which the diameter gradually increases as it goes to the rear end side. And the contact surface between the ring member and the wall surface of the blade portion is extended so as to be orthogonal to the axis of the tool body, and the contact surface between the ring member and the wall surface of the blade portion is the rear end. The taper is formed such that the diameter gradually decreases toward the side, and the contact surface between the ring member and the front end surface of the tool body is formed in a taper shape where the diameter gradually increases toward the rear end. Of what is being done And satisfies the one or Re,
When the blade portion is pulled toward the rear end side in the axial direction of the tool body, the ring member is elastically deformed so as to be expanded toward the radially outer side, and the diameter thereof is increased. Blade type replaceable cutting tool.

In the blade part exchange-type cutting tool according to claim 1,
The blade part exchangeable cutting tool, wherein a taper angle at one angle on the contact surface is set in a range of 10 to 80 °.

In the blade part exchangeable cutting tool according to claim 1 or 2,
The blade part replaceable cutting tool, wherein the blade part is made of cemented carbide.