JP3795722B2

JP3795722B2 - Medical cutting instrument and sealing member for medical cutting instrument

Info

Publication number: JP3795722B2
Application number: JP2000019316A
Authority: JP
Inventors: 徳之田中; 浩文竺原; 哲也高志
Original assignee: J Morita Manufaturing Corp
Current assignee: J Morita Manufaturing Corp
Priority date: 2000-01-27
Filing date: 2000-01-27
Publication date: 2006-07-12
Anticipated expiration: 2020-01-27
Also published as: JP2001204740A

Description

【０００１】
【発明の属する技術分野】
この発明は、歯科における診療などに用いられる医療用切削器械と、この医療用切削器械に使用されるシール部材に関するものである。
【０００２】
【従来の技術】
例えば歯科の診療においては、ヘッドにダイアモンドポイントバーやカーバイドバーあるいはファイルやリーマ等の切削工具を装着したエアータービンハンドピースやマイクロモータハンドピース、スケーラ等の各種の切削器械が使用されている。この種の切削器械では、切削工具がヘッドから外部に突出する部分には切削工具の周囲に環状の隙間があり、使用時にはこの隙間から切削で生じた歯の粉や唾液、血液等の異物が侵入してヘッドの内部が汚染される可能性がある。なお、器械の種類によっては切削工具保持具がヘッド外部まで突出し、その周囲に環状の隙間が形成される場合もある。以下、切削工具と切削工具保持具が回転するものである場合にはこれらの総称として回転軸なる用語を用いる場合がある。
【０００３】
このため、切削器械は使用後に洗浄を行い、更にオートクレーブ等による滅菌処理が行われるのであるが、この処理は操作が煩雑である上に、高温の高圧蒸気によって器械の劣化が生ずるという問題がある。また汚染物質である上記の異物が、作動媒体供給用のチューブに侵入したり、更に制御ユニットにまで達することがあり、チューブやユニットの滅菌処理は切削器械以上に困難であると共に、処理によってこれらの機器類を劣化させてしまうという問題が生ずる。この汚染を防ぐにはシール部材によって上記の隙間を無くせばよいが、回転軸は１分に数万回あるいは数十万回という高速回転が普通であるため、シール部材が回転軸に接触する部分は摩擦による発熱に耐えられないと考えられていた。
【０００４】
このため、例えば実公昭６０−７６９２号公報には、シール部材を備えた防塵カバーをヘッドの先端に設け、回転軸が撓んだ場合にはシール部材が共に回転して摩耗しないようにしたものが提案されている。また、実公平７−３７６０５号公報には、回転軸の先端部分にディスクを設けてその遠心力で異物を排除し、ヘッド内まで異物が侵入しないようにしたものが提案されている。しかしながら、これらは隙間が完全に塞がれるわけではなく、異物侵入を防止するには不十分な構成であった。
【０００５】
また例えば特開平９−１０８２３９号公報には、作動用の給気がオフされた瞬間に排気孔を閉じてタービンの惰性回転による吸引を防止するようにしたものが提案されているが、弁の動作遅れなどによって吸引が生ずる可能性があり、また弁を必要として構造が複雑になったり、故障しやすくなったりするという問題点が考えられる。同様に排気孔への吸引を防止するために、回転軸近傍の領域と排気孔を連通させたものも提案されているが、これもタービンの惰性回転による吸引を完全に防止するこは困難と考えられる（例えば米国特許第５８０７１０８号明細書参照）。
【０００６】
更に、上記の例では切削器械の内部に加工を施し、あるいは精密に加工されたタービンやその回転軸を再加工する必要があり、構造も複雑になるのでコスト高となる。また歯科用切削器械では、危険防止のためにヘッドを口腔内に挿入した状態でオン・オフが行われるのが普通であり、器械が作動していない時にヘッドの先端が口腔内のどこかに触れると、塞がれていない隙間から汚染物質が確実に侵入するので、汚染を完全に防止するには不十分な構成である。
【０００７】
【発明が解決しようとする課題】
この発明はこれらの点に着目し、シール部材の配置と形状に改良を加えて切削工具または切削工具保持具の周囲に生ずる隙間を塞ぐようにして上記の諸問題を解決することを課題としてなされたものである。なおこの発明は、超音波スケーラのように切削工具が回転しない器械にも適用できるほか、歯科用だけでなく外科用や口腔外科用を含む一般医療用切削器械にも適用できる。
【０００８】
【課題を解決するための手段】
上記の課題を達成するために、この発明の医療用切削器械では、ヘッドに装着された切削工具または切削工具保持具の周囲に環状の隙間が形成される部分にシール部材を設け、切削工具または切削工具保持具に接触して上記隙間を塞ぐ接触片を上記シール部材に環状に形成し、少なくとも上記接触片の切削工具または切削工具保持具に接触する部分を弾性体で構成すると共に、上記接触片が、切削工具の作動時に上昇するヘッド内部の作動気体の圧力によって外側に押し開かれて切削工具または切削工具保持具から離れ、切削工具の不作動時には閉じて上記隙間を塞ぐように構成している。このような構成により、切削工具が作動していない時は隙間が塞がれるので汚染物質のヘッド内への侵入が確実に防止され、切削工具の作動中は隙間から出る気体に逆らって汚染物質がヘッド内に侵入することはなく、ヘッドから漏れる作動音も小さくなる。また、切削工具の作動中はシール部材が工具に接触しなくなるので、切削工具が回転するタイプの場合でも高速回転中の回転軸に触れることによる損耗は全く発生せず、切削工具または切削工具保持具に接触する部分が弾性体であるため必要以上に強く接触することがなく、仮に高速の回転軸に触れていても摩擦による損耗はほとんど生じない。
【０００９】
また、ヘッドに装着された切削工具または切削工具保持具の周囲に環状の隙間が形成される部分にシール部材を設け、切削工具または切削工具保持具に接触して上記隙間を塞ぐ接触片を上記シール部材に環状に形成し、少なくとも上記接触片の切削工具または切削工具保持具に接触する部分を弾性体で構成すると共に、上記接触片と切削工具または切削工具保持具とが相互に接触する部分を水によって冷却する冷却手段を備えている。この冷却手段は、該当する部分に直接注水したり、その近傍のヘッド内に冷却水を循環させて間接的に冷却したりすることで実現でき、このような構成によって、隙間が塞がれているので汚染物質のヘッド内への侵入が防止され、接触する部分の発熱が軽減されるので、高速の回転軸に触れることによる損耗は発生しにくくなる。
【００１０】
また上記のシール部材は、接触片の断面形状を、切削工具または切削工具保持具に接触する部分に近くなるほど厚みが薄くなるテーパ状としている。このような構成により、接触片の柔軟性が増して接触部分での接触負荷を小さくすることができ、接触音の発生や振動も防止できる。
【００１１】
また、接触片の少なくとも切削工具または切削工具保持具に接触する部分は摩擦係数の低い材料で構成される。これは、該当する部分を四フッ化エチレンやパリレン樹脂のような摩擦係数の低い物質でコーティングしたり、含油ゴムや四フッ化エチレン入りゴムのような摩擦係数を低下させる物質を混入した材料で構成することによって実現できる。このような構成により、高速の回転軸に触れることによる損耗は発生しにくくなる。
【００１３】
上記のように接触片が回転軸に触れることによる損耗を防止できても、シール部材は消耗品であるから容易に交換できることが望ましい。このため、シール部材を切削器械本体に対して着脱可能とするための係合部が、シール部材及び切削器械本体にそれぞれ設けられる。この場合、係合部の少なくとも一方を弾性変形可能な構成とすることが望ましく、これにより着脱操作が容易になると共に装着状態の維持が確実となる。
【００１４】
また、切削器械の本体を覆うカバー部材を備えてもよい。この場合には、カバー部材には切削工具貫通穴が形成され、この穴を囲むようにシール部材が一体に形成される。このような構成により、切削器械はヘッド内だけでなく外面の汚染も防止することが可能となる。
【００１５】
この発明が適用される切削器械は、例えば歯科の診療等で用いられる医療用エアータービンハンドピースや医療用マイクロモータハンドピースであり、これらのハンドピースを用いた診療における感染等の可能性を大幅に低減し、安全性が向上される。
【００１６】
また、この発明のシール部材は上記のような切削器械が実現されるように構成される。なお、切削器械本体に対して着脱可能とするための係合部としては、例えばゴム製のＯリング状のものが適しており、これに対応して器械本体側にはＯリング溝に相当する係合溝を設け、この溝にはめ込んで装着される。
【００１７】
【発明の実施の形態】
次に、実施の形態について説明する。図１はエアータービンハンドピースにこの発明を適用した例におけるヘッドの断面図、図２はシール部材の断面図、図３は動作状態の説明図であって、１はハンドピース本体、２は本体１の先端部分に設けられているヘッド、３は切削工具、４はシール部材である。
【００１８】
ヘッド２は、アウターハウジング２ａの内部にインナーハウジング２ｂが設けられ、その内部にブレード２ｃを備えたスピンドル２ｄをベアリング２ｅを介して支持している。スピンドル２ｄは切削工具保持具を兼ねており、これにシャフト３ａを支持された切削工具３がヘッド２から外部に突出している。ハンドピース本体１には、作動気体である高圧エアーの供給ダクト１ａとリターンダクト１ｂ、洗浄水供給ダクト１ｃと噴霧エアー供給ダクト１ｄ等が備えられている。これらの構成と動作は周知のハンドピースと基本的には変わらないので、これ以上の説明は省略する。
【００１９】
スピンドル２ｄの先端はインナーハウジング２ｂの下面、すなわち切削工具３の突出部分まで延びており、インナーハウジング２ｂとスピンドル２ｄとの間には環状の隙間５が形成されている。シール部材４は例えばゴム成形品であって図２に示すような浅い有底円筒状であり、端縁に相当する部分には断面が円形でＯリング状になっている係合部４ａが設けられ、また底に相当する部分の中央には切削工具３が通る貫通穴４ｂが設けられ、その周縁は切削工具３のシャフト３ａに近いほど厚みが薄くなった断面テーパ状の接触片４ｃとなっている。これに対応して、インナーハウジング２ｂの下面の切削工具３が突出する部分には係合溝２ｆがリング状に形成されている。なおこの明細書においては、「テーパ状」の語を一方の面が他方の面に対して相対的に傾斜して厚みが変化する状態の意味で使用している。
【００２０】
シール部材４は貫通穴４ｂの内径を切削工具３のシャフト３ａの外径よりも僅かに小さく選定してあり、係合溝２ｆに係合部４ａを係合させることによってヘッド２に装着される。この装着状態では、接触片４ｃはシャフト３ａに押し広げられると共に切削工具３の先端方向、つまり外側に若干押し曲げられ、シャフト３ａに密着して上記の隙間５を塞ぐ状態となる。図３の左側はこの状態を例示したものである。なお、シール部材４の係合部４ａとインナーハウジング２ｂの係合溝２ｆは、いずれか一方が弾性変形可能であればシール部材４の着脱を容易に行えるが、この例ではシール部材４がゴム製であるため係合部４ａが変形可能となっている。
【００２１】
この実施の形態は上述のような構成であり、供給ダクト１ａから作動気体である高圧エアーが供給されるとスピンドル２ｄと切削工具３が高速で回転する。この作動時には高圧エアーの大部分はリターンダクト１ｂを経て回収されるが、ヘッド２の内部の圧力が高くなるため、エアーの一部はシャフト３ａに接触している接触片４ｃの貫通穴４ｂの部分を外側に押し開き、図３の右側に矢印で示すようにこの部分から外部に放出される。このため、接触片４ｃは切削工具３のシャフト３ａから僅かに離れて直接には接触しない状態となり、接触による損耗は全く発生しなくなる。しかもこのシャフト３ａと接触片４ｃとの間の隙間からはエアーが噴出するので、切削によって生じた歯の粉や血液などの異物がヘッド２内に侵入することはない。
【００２２】
また、エアーの供給を止めて作動を停止させた場合には、接触片４ｃは元の形状に戻って上記の隙間が塞がれるので、作動停止中に汚染物質がヘッド２内に侵入することはなく、更にシャフト３ａと接触片４ｃとの接触により、エアーの供給を止めてから実際に切削工具３が停止するまでの時間が短縮されるという効果も得られる。
【００２３】
上述の例では、シール部材４は接触片４ｃがシャフト３ａに密着して隙間５を塞いでいるが、隙間５を塞ぐ態様はこれに限定されるものではない。図４及び図５は、スピンドル２ｄの先端がインナーハウジング２ｂの下面よりも若干突出するような形状の場合である。すなわち、図４ではシール部材４の貫通穴４ｂはシャフト３ａの外径よりも大きくなっており、接触片４ｃはシャフト３ａではなくスピンドル２ｄのラジアル方向の端面に接触して隙間５を塞いでいる。また図５では接触片４ｃがスピンドル２ｄのスラスト方向の周面に接触して隙間５を塞いでおり、図５のシール部材４は図２に示したものとは異なる形状となっている。このように、シール部材４の形状や隙間５を塞ぐ態様はヘッド２の形状などに応じて適宜選択すればよく、接触片４ｃは図１や図３のように切削工具３のスラスト方向の周面に接触するだけでなく、例えば図４や図５のように切削工具保持具に相当するスピンドル２ｄのスラスト方向の周面またはラジアル方向の端面に接触させてもよい。
【００２４】
なお、図５はギヤ１ｅ、１ｆを介して切削工具３を駆動するマイクロモータハンドピースの場合の例であり、タービン駆動用の高圧エアーは供給されないが、作動時にはモータやギヤ部の冷却のために図示しないダクトから冷却用エアーが供給される。従って、エアータービンハンドピースの場合と同様に作動中はヘッド２内の圧力は高くなり、隙間５を塞いでいる接触片４ｃが外側に押し開かれてスピンドル２ｄに接触しない状態となる。
【００２５】
上述の例におけるシール部材４は例えばゴム成形品であるが、他の適宜の弾性材料を用いることができる。特に、図４のようにスピンドル２ｄの端面に接触する構造の場合には、シール部材４として金属のベローズ構造のもの（図示せず）を用いることも可能である。またシール部材４の材料が柔軟なものであれば、ヘッド２の内部圧力によって外側に押し開かれやすくなり、また内外の圧力差が小さくて外側への押し開きが少なく、接触が生ずるような場合であっても接触圧力が小さくなるので、上記の損耗防止の効果がより確実となる。なお材料がゴム系の場合でも、好ましくはオートクレーブ等の滅菌処理に耐えられる材質の方がよく、例えばシリコーンゴム、フッ素ゴム、パーフロロ系ゴム、ＥＰＤＭ（エチレン・プロピレンゴム）、Ｈ−ＮＢＲ（水素化ニトリルゴム）等を用いることが望ましい。
【００２６】
またシール部材４は、少なくとも接触片４ｃの貫通穴４ａの部分、すなわち切削工具３やスピンドル２ｄに接触する部分を、例えば４フッ化エチレン樹脂やパリレン樹脂等の摩擦係数の低い材料でコーティングし、あるいは摩擦係数の低い材料、例えば含油ゴムや４フッ化エチレン入りゴム等で形成してもよく、切削工具３やスピンドル２ｄと接触した際の摩耗防止の効果が高くなる。これは、作動用の高圧エアーを用いないためヘッド内部の圧力と外部の圧力の差がそれほど大きくならず、接触片４ｃが押し開かれる度合いが少なくて接触が起きる可能性のあるマイクロモータハンドピースなどでは特に効果がある。
【００２７】
図６は、シール部材４と切削工具３あるいはスピンドル２ｄとが接触する部分を積極的に冷却するようにした例である。すなわち、洗浄水供給ダクト１ｃの出口にノズル１ｇを設け、接触片４ｃとシャフト３ａの接触部分に洗浄水の一部を冷却水として直接噴射するようにしたものであり、仮に摩擦熱が生ずるような相互接触が起きても、噴射される冷却水１ｈで冷却されるので発熱による損耗が発生しにくくなる。なお、図６のように接触部分に直接注水せず、例えばアウターハウジング２ａやインナーハウジング２ｂのシール部材４が取り付けられている部分に冷却水を循環させ、間接的に冷却するような構造も可能である。
【００２８】
ところで、ヘッド２を含むハンドピース本体１の先端部分は、診療中に患者の口腔に触れたりして汚染される可能性が大きいので、上述のシール部材４のように隙間５を塞ぐだけでなく、カバー部材によって少なくとも本体１の先端部分の全体を覆うことができれば好都合である。図７及び図８はこのようなカバー部材にシール部材を一体に形成した例であり、６はこのカバー部材を示す。
【００２９】
すなわち、カバー部材６は薄い弾性材料を用いてハンドピース本体１の外面と同じ形状となるように形成されたもので、本体１の先端から中央よりやや後ろ寄りまでを覆う長さとなっており、本体１に装着した際には本体１の表面に密着するようになっている。ヘッド２から切削工具３が突出する部分にはシール部材６ａが一体に形成され、また洗浄水供給ダクト１ｃと噴霧エアー供給ダクト１ｄに対応して必要な開口部６ｂが形成されており、切削工具３はシール部材６ａの貫通穴６ｃを通って外部に突出する。シール部材６ａの形状は前述したシール部材４に準じたものとなっており、カバー部材６を装着して係合部６ｅを係合溝２ｆに係合させると、接触片６ｄがシャフト３ａに接触して隙間５が塞がれる。
【００３０】
なお図示していないが、必要に応じて、ダクト１ｃ及び１ｄの開口部の周囲に環状の係合溝を設けると共にこの係合溝に対応して環状のＯリング部をカバー部材６に設けて、上述の係合溝２ｆと係合部６ｅとの組み合わせに準じた構造の係合手段を形成してもよい。このようにすれば、開口部６ｂから汚染物質がカバー部材６の内面に侵入することも防止できる。
【００３１】
このような構成により、シール部材６ａで隙間５が塞がれてヘッド２内の汚染が防止されると共に、ハンドピース本体１は少なくとも先端部分がカバー部材６で覆われるので本体１の汚染も防止される。またカバー部材６は、後端６ｆの部分から先端に向けて巻き上げることによって本体１から外すことができ、逆の操作で装着することができるので、カバー部材６が汚染されたり破損したりした際の交換は容易に行うことができる。
【００３２】
【発明の効果】
以上の説明から明らかなように、この発明の医療用切削器械は、ヘッドに装着された切削工具がヘッドから外部に突出して切削工具または切削工具保持具の周囲に環状の隙間が形成される部分にシール部材を設け、切削工具または切削工具保持具に接触して上記隙間を塞ぐ接触片を上記シール部材に環状に形成すると共に、少なくとも上記接触片の切削工具または切削工具保持具に接触する部分を弾性体で構成したものである。従って、シール部材の損耗は小さく、比較的簡単な構造によって隙間を塞いで汚染物質の侵入を防止でき、操作が煩雑であると共に機器を劣化させる可能性のあるオートクレーブ等による滅菌処理の回数を低減し、汚染物質がチューブや制御ユニットに侵入する可能性も減らすことができるのである。
【００３３】
また、上記のシール部材の接触片の断面形状を、切削工具または切削工具保持具に接触する部分に近くなるほど厚みが薄くなったテーパ状としている。従って、接触部分での接触負荷を小さくすることができ、接触音の発生や振動も防止することができる。
【００３４】
またシール部材の接触片が、切削工具の作動時に上昇するヘッド内部の作動気体の圧力によって外側に押し開かれて切削工具または切削工具保持具から離れ、切削工具の不作動時には閉じて上記隙間を塞ぐように構成しているので、作動中の切削工具にシール部材が接触しなくなるので、特に切削工具が回転するタイプの場合における接触による損耗が全く発生しなくなる。しかも作動中は隙間から気体が噴出しているので汚染物質がヘッド内に侵入することはなく、ヘッドから漏れる作動音も小さくなり、作動停止後は隙間が塞がれるので汚染物質のヘッド内への侵入が確実に防止される。
【００３５】
また、シール部材の接触片の少なくとも切削工具または切削工具保持具に接触する部分を摩擦係数の低い材料で構成したものでは、高速で回転中の切削工具などに触れることによる損耗が発生しにくくなる。
【００３６】
更に、シール部材の接触片と切削工具または切削工具保持具との接触部分を水によって冷却する冷却手段を設けているので、接触部分の発熱が軽減されて高速の回転中の切削工具などに触れても損耗しにくくなる。
【００３７】
また、シール部材を切削器械本体に対して着脱可能とするための係合部をシール部材及び切削器械本体にそれぞれ設けたものでは、シール部材の着脱操作が容易であり、特に係合部の少なくとも一方を弾性変形可能に構成したものでは、着脱操作が一層容易になる。
【００３８】
また、切削器械の本体を覆うカバー部材にシール部材を一体に形成したものでは、ヘッド内だけでなく切削器械本体の外面の汚染も防止されるので、滅菌処理の回数を低減できるなど、切削器械の管理が容易となる。
【００３９】
また、この発明を医療用エアータービンハンドピースや医療用マイクロモータハンドピースに適用したものでは、例えば歯科診療などにおける感染の可能性が大幅に低減され、診療時の安全性が向上する。
【００４０】
この発明の医療用切削器械用シール部材は、上記の切削器械に用いられるものであって上述のように構成され、切削器械に装着することによって上述のような作用効果を発揮することができる。
【図面の簡単な説明】
【図１】この発明の一実施形態のヘッドの断面図である。
【図２】同上におけるシール部材の断面図である。
【図３】同上の動作説明図である。
【図４】他の実施形態におけるヘッドの断面図である。
【図５】同じく他の実施形態におけるヘッドの断面図である。
【図６】同じく他の実施形態におけるヘッドの断面図である。
【図７】別の実施形態における切削器械の側面図である。
【図８】同上におけるヘッドの断面図である。
【符号の説明】
１ハンドピース本体
１ｇノズル
２ヘッド
２ｄスピンドル
２ｆ係合溝
３切削工具
３ａシャフト
４シール部材
４ａ係合部
４ｃ接触片
５隙間
６カバー部材
６ａシール部材
６ｄ接触片[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a medical cutting instrument used for medical treatment in dentistry, and a seal member used in the medical cutting instrument.
[0002]
[Prior art]
For example, in dental practice, various cutting instruments such as an air turbine handpiece, a micromotor handpiece, a scaler, etc., equipped with a diamond point bar, a carbide bar or a cutting tool such as a file or a reamer are used. In this type of cutting machine, there is an annular gap around the cutting tool where the cutting tool protrudes from the head, and during use, foreign substances such as tooth powder, saliva, blood, etc. generated by cutting from this gap. There is a possibility that the inside of the head may be contaminated. Depending on the type of instrument, the cutting tool holder may protrude to the outside of the head, and an annular gap may be formed around the cutting tool holder. Hereinafter, when the cutting tool and the cutting tool holder are rotating, the term “rotary axis” may be used as a general term.
[0003]
For this reason, the cutting machine is cleaned after use, and further sterilized by an autoclave or the like. However, this process is complicated and there is a problem that the instrument is deteriorated by high-temperature high-pressure steam. . In addition, the contaminants mentioned above may enter the working medium supply tube or even reach the control unit. Sterilization of the tube or unit is more difficult than the cutting instrument. This causes the problem of degrading the devices. In order to prevent this contamination, the gap may be eliminated by a seal member. However, since the rotary shaft normally rotates at a high speed of tens of thousands or hundreds of thousands per minute, the portion where the seal member contacts the rotary shaft. Was thought to be unable to withstand the heat generated by friction.
[0004]
For this reason, for example, in Japanese Utility Model Publication No. 60-7692, a dustproof cover provided with a seal member is provided at the tip of the head so that when the rotary shaft is bent, the seal member rotates together and does not wear. Has been proposed. Japanese Utility Model Publication No. 7-37605 proposes a disk in which a disk is provided at the tip of a rotating shaft and foreign matter is removed by the centrifugal force so that the foreign matter does not enter the head. However, these gaps are not completely closed, and the structure is insufficient to prevent entry of foreign matter.
[0005]
Further, for example, Japanese Patent Laid-Open No. 9-108239 proposes a valve that closes the exhaust hole at the moment when the air supply for operation is turned off to prevent suction due to inertial rotation of the turbine. There is a possibility that suction may occur due to an operation delay or the like, and there is a problem that a valve is required and the structure becomes complicated or is likely to break down. Similarly, in order to prevent suction to the exhaust hole, there has been proposed one in which the region near the rotation shaft and the exhaust hole are communicated with each other. However, it is difficult to completely prevent suction due to inertial rotation of the turbine. (For example, see US Pat. No. 5,807,108).
[0006]
Furthermore, in the above example, it is necessary to process the inside of the cutting machine, or to rework a precisely machined turbine and its rotating shaft, which increases the cost because the structure becomes complicated. Also, dental cutting instruments are usually turned on and off with the head inserted into the oral cavity to prevent danger, and the tip of the head is somewhere in the oral cavity when the instrument is not operating. When touched, contaminants will surely enter through the unoccluded gap, which is insufficient to completely prevent contamination.
[0007]
[Problems to be solved by the invention]
This invention pays attention to these points, and makes it a subject to solve the above-mentioned problems by improving the arrangement and shape of the seal member so as to close the gap generated around the cutting tool or the cutting tool holder. It is a thing. The present invention can be applied not only to an instrument in which a cutting tool does not rotate, such as an ultrasonic scaler, but also to general medical cutting instruments including not only dental but also surgical and oral surgery.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the medical cutting instrument of the present invention, a sealing member is provided in a portion where an annular gap is formed around a cutting tool or a cutting tool holder mounted on the head, and the cutting tool or A contact piece that contacts the cutting tool holder and closes the gap is formed in the seal member in an annular shape, and at least a portion of the contact piece that contacts the cutting tool or the cutting tool holder is formed of an elastic body, and the contact The piece is configured to be pushed outward by the pressure of the working gas inside the head that rises when the cutting tool is operated to move away from the cutting tool or the cutting tool holder, and to close when the cutting tool is inactive and close the gap. ing. With such a configuration, when the cutting tool is not operating, the gap is closed, so that the entry of contaminants into the head is surely prevented. Does not enter the head, and the operating sound leaking from the head is also reduced. In addition, since the sealing member does not come into contact with the tool during the operation of the cutting tool, even when the cutting tool rotates, there is no wear caused by touching the rotating shaft during high-speed rotation. Since the portion in contact with the tool is an elastic body, it does not contact more strongly than necessary, and even if the high-speed rotating shaft is touched, wear due to friction hardly occurs.
[0009]
Further, a sealing member is provided in a portion where an annular gap is formed around the cutting tool or cutting tool holder mounted on the head, and the contact piece that contacts the cutting tool or cutting tool holder and closes the gap is provided above. The seal member is formed in an annular shape, and at least a portion of the contact piece that contacts the cutting tool or the cutting tool holder is formed of an elastic body, and the contact piece and the cutting tool or the cutting tool holder are in contact with each other. Cooling means for cooling with water. This cooling means can be realized by directly injecting water into the corresponding part or by indirectly cooling by circulating the cooling water in the head in the vicinity thereof. With such a configuration, the gap is closed. As a result, entry of contaminants into the head is prevented and heat generation at the contact portion is reduced, so that wear due to touching the high-speed rotating shaft is less likely to occur.
[0010]
Moreover, said sealing member is making the cross-sectional shape of a contact piece into the taper shape from which thickness becomes thin, so that it becomes close to the part which contacts a cutting tool or a cutting tool holder. With such a configuration, the flexibility of the contact piece can be increased, the contact load at the contact portion can be reduced, and the generation of contact noise and vibration can also be prevented.
[0011]
Further, at least a portion of the contact piece that contacts the cutting tool or the cutting tool holder is made of a material having a low friction coefficient. This is a material in which the relevant part is coated with a material with a low coefficient of friction such as tetrafluoroethylene or parylene resin, or a material that reduces the coefficient of friction such as oil-impregnated rubber or rubber containing tetrafluoroethylene. This can be realized by configuring. With such a configuration, wear due to touching a high-speed rotating shaft is less likely to occur.
[0013]
Even if it is possible to prevent wear due to the contact piece coming into contact with the rotating shaft as described above, it is desirable that the seal member can be easily replaced because it is a consumable item. For this reason, the engaging part for making a sealing member detachable with respect to a cutting machine main body is provided in a sealing member and a cutting instrument main body, respectively. In this case, it is desirable that at least one of the engaging portions be elastically deformable, thereby facilitating the attachment / detachment operation and ensuring the attachment state.
[0014]
Moreover, you may provide the cover member which covers the main body of a cutting instrument. In this case, a cutting tool through hole is formed in the cover member, and a seal member is integrally formed so as to surround the hole. With this configuration, the cutting machine can prevent contamination not only in the head but also on the outer surface.
[0015]
Cutting machines to which the present invention is applied are, for example, medical air turbine handpieces and medical micromotor handpieces used in dental practice, and the possibility of infection in medical care using these handpieces is greatly increased. The safety is improved.
[0016]
In addition, the sealing member of the present invention is configured to realize the above cutting machine. For example, a rubber O-ring-shaped member is suitable as an engagement portion that can be attached to and detached from the cutting instrument body, and corresponds to an O-ring groove on the instrument body side. An engaging groove is provided and fitted into this groove.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments will be described. FIG. 1 is a sectional view of a head in an example in which the present invention is applied to an air turbine handpiece, FIG. 2 is a sectional view of a seal member, FIG. 3 is an explanatory view of an operation state, 1 is a handpiece main body, 2 is a main body 1 is a head provided at the tip of 1, 3 is a cutting tool, and 4 is a seal member.
[0018]
The head 2 is provided with an inner housing 2b inside an outer housing 2a, and supports a spindle 2d provided with a blade 2c therein via a bearing 2e. The spindle 2d also serves as a cutting tool holder, and the cutting tool 3 supported by the shaft 3a projects from the head 2 to the outside. The handpiece body 1 is provided with a supply duct 1a and a return duct 1b for high-pressure air that is working gas, a washing water supply duct 1c, a spray air supply duct 1d, and the like. Since these configurations and operations are basically the same as those of known handpieces, further explanation is omitted.
[0019]
The tip of the spindle 2d extends to the lower surface of the inner housing 2b, that is, the protruding portion of the cutting tool 3, and an annular gap 5 is formed between the inner housing 2b and the spindle 2d. The sealing member 4 is, for example, a rubber molded product and has a shallow bottomed cylindrical shape as shown in FIG. 2, and an engagement portion 4a having a circular cross section and an O-ring shape is provided at a portion corresponding to the edge. In addition, a through hole 4b through which the cutting tool 3 passes is provided in the center of the portion corresponding to the bottom, and the peripheral edge thereof becomes a contact piece 4c having a tapered cross section whose thickness becomes thinner as the shaft 3a of the cutting tool 3 is closer. ing. Correspondingly, an engagement groove 2f is formed in a ring shape in a portion of the lower surface of the inner housing 2b where the cutting tool 3 protrudes. In this specification, the term “tapered” is used to mean a state in which one surface is inclined relative to the other surface and the thickness changes.
[0020]
The sealing member 4 is selected so that the inner diameter of the through hole 4b is slightly smaller than the outer diameter of the shaft 3a of the cutting tool 3, and is attached to the head 2 by engaging the engaging portion 4a with the engaging groove 2f. . In this mounted state, the contact piece 4c is pushed and spread on the shaft 3a and is slightly pushed and bent toward the distal end of the cutting tool 3, that is, outward, so as to be in close contact with the shaft 3a and close the gap 5. The left side of FIG. 3 illustrates this state. The engagement member 4a of the seal member 4 and the engagement groove 2f of the inner housing 2b can be easily attached and detached if either one can be elastically deformed. In this example, the seal member 4 is a rubber member. Since it is made, the engaging portion 4a can be deformed.
[0021]
This embodiment is configured as described above. When high-pressure air that is working gas is supplied from the supply duct 1a, the spindle 2d and the cutting tool 3 rotate at high speed. During this operation, most of the high-pressure air is collected through the return duct 1b. However, since the pressure inside the head 2 is increased, a part of the air passes through the through hole 4b of the contact piece 4c that is in contact with the shaft 3a. The part is pushed outward and released from this part as indicated by the arrow on the right side of FIG. For this reason, the contact piece 4c is slightly separated from the shaft 3a of the cutting tool 3 and is not in direct contact with the contact piece 4c, and wear due to contact does not occur at all. In addition, since air is ejected from the gap between the shaft 3a and the contact piece 4c, foreign matter such as tooth powder and blood generated by cutting does not enter the head 2.
[0022]
Further, when the operation is stopped by stopping the supply of air, the contact piece 4c returns to its original shape and the gap is closed, so that contaminants enter the head 2 while the operation is stopped. In addition, the contact between the shaft 3a and the contact piece 4c also provides an effect that the time from when the supply of air is stopped until the cutting tool 3 actually stops is shortened.
[0023]
In the above example, the seal member 4 has the contact piece 4c in close contact with the shaft 3a to close the gap 5. However, the mode of closing the gap 5 is not limited to this. 4 and 5 show a case where the tip of the spindle 2d is slightly protruded from the lower surface of the inner housing 2b. That is, in FIG. 4, the through hole 4b of the seal member 4 is larger than the outer diameter of the shaft 3a, and the contact piece 4c contacts the radial end face of the spindle 2d instead of the shaft 3a to close the gap 5. . In FIG. 5, the contact piece 4c contacts the circumferential surface of the spindle 2d in the thrust direction to close the gap 5, and the seal member 4 in FIG. 5 has a shape different from that shown in FIG. As described above, the shape of the seal member 4 and the mode of closing the gap 5 may be appropriately selected according to the shape of the head 2 and the like, and the contact piece 4c is arranged around the thrust direction of the cutting tool 3 as shown in FIGS. In addition to contacting the surface, for example, as shown in FIGS. 4 and 5, the peripheral surface in the thrust direction or the end surface in the radial direction of the spindle 2 d corresponding to the cutting tool holder may be contacted.
[0024]
FIG. 5 shows an example of a micromotor handpiece that drives the cutting tool 3 via the gears 1e and 1f, and high-pressure air for driving the turbine is not supplied. The cooling air is supplied from a duct (not shown). Therefore, as in the case of the air turbine handpiece, during operation, the pressure in the head 2 becomes high, and the contact piece 4c closing the gap 5 is pushed outward and is not in contact with the spindle 2d.
[0025]
The seal member 4 in the above example is, for example, a rubber molded product, but other appropriate elastic materials can be used. In particular, in the case of a structure in contact with the end surface of the spindle 2d as shown in FIG. 4, a metal bellows structure (not shown) may be used as the seal member 4. Also, if the material of the seal member 4 is flexible, it can be easily pushed outward by the internal pressure of the head 2, and the pressure difference between the inside and outside is small so that the outward opening is small and contact occurs. However, since the contact pressure is reduced, the above-described effect of preventing wear is further ensured. Even when the material is rubber, it is preferable to use a material that can withstand sterilization such as autoclave. For example, silicone rubber, fluorine rubber, perfluoro rubber, EPDM (ethylene propylene rubber), H-NBR (hydrogenation) Nitrile rubber) or the like is desirable.
[0026]
Further, the sealing member 4 coats at least the part of the through hole 4a of the contact piece 4c, that is, the part that contacts the cutting tool 3 or the spindle 2d with a material having a low friction coefficient such as tetrafluoroethylene resin or parylene resin, Alternatively, it may be formed of a material having a low friction coefficient, such as oil-impregnated rubber or rubber containing tetrafluoroethylene, and the effect of preventing wear when contacting the cutting tool 3 or the spindle 2d is enhanced. This is because the difference between the pressure inside the head and the pressure outside the head is not so great because high pressure air for operation is not used, and the contact piece 4c is less likely to be pushed open, and contact may occur. Is particularly effective.
[0027]
FIG. 6 shows an example in which the portion where the seal member 4 and the cutting tool 3 or the spindle 2d come into contact with each other is actively cooled. That is, a nozzle 1g is provided at the outlet of the cleaning water supply duct 1c, and a part of the cleaning water is directly injected as cooling water to the contact portion between the contact piece 4c and the shaft 3a so that frictional heat is generated. Even if such mutual contact occurs, since it is cooled by the injected cooling water 1h, wear due to heat generation is less likely to occur. In addition, as shown in FIG. 6, it is possible to have a structure in which cooling water is circulated to the portion where the seal member 4 of the outer housing 2a or the inner housing 2b is attached and cooled indirectly, for example, without direct water injection to the contact portion. It is.
[0028]
By the way, since the tip part of the handpiece body 1 including the head 2 is likely to be contaminated by touching the oral cavity of the patient during medical treatment, not only the gap 5 is blocked as in the above-described seal member 4. It is advantageous if at least the entire tip portion of the main body 1 can be covered with the cover member. 7 and 8 show an example in which a sealing member is integrally formed on such a cover member, and 6 shows the cover member.
[0029]
That is, the cover member 6 is formed so as to have the same shape as the outer surface of the handpiece body 1 using a thin elastic material, and has a length that covers from the front end of the body 1 to slightly behind the center, When attached to the main body 1, it is in close contact with the surface of the main body 1. A seal member 6a is integrally formed at a portion where the cutting tool 3 protrudes from the head 2, and a necessary opening 6b is formed corresponding to the cleaning water supply duct 1c and the spray air supply duct 1d. 3 protrudes outside through the through-hole 6c of the seal member 6a. The shape of the seal member 6a conforms to the seal member 4 described above, and when the cover member 6 is attached and the engaging portion 6e is engaged with the engaging groove 2f, the contact piece 6d contacts the shaft 3a. As a result, the gap 5 is closed.
[0030]
Although not shown, if necessary, an annular engagement groove is provided around the openings of the ducts 1c and 1d, and an annular O-ring portion is provided in the cover member 6 corresponding to the engagement groove. The engaging means may have a structure according to the combination of the engaging groove 2f and the engaging portion 6e. If it does in this way, it can also prevent that a pollutant penetrate | invades into the inner surface of the cover member 6 from the opening part 6b.
[0031]
With such a configuration, the gap 5 is closed by the seal member 6a to prevent contamination in the head 2, and at least the tip of the handpiece body 1 is covered with the cover member 6, so that the contamination of the body 1 is also prevented. Is done. Further, the cover member 6 can be detached from the main body 1 by being rolled up from the rear end 6f toward the front end, and can be mounted by the reverse operation. Therefore, when the cover member 6 is contaminated or damaged. Can be easily exchanged.
[0032]
【The invention's effect】
As is apparent from the above description, the medical cutting instrument of the present invention is a portion in which an annular gap is formed around a cutting tool or a cutting tool holder by a cutting tool mounted on the head projecting outward from the head. The seal member is provided with a contact piece that closes the gap by contacting the cutting tool or the cutting tool holder, and at least a portion of the contact piece that contacts the cutting tool or the cutting tool holder. Is made of an elastic body. Therefore, the wear of the seal member is small, and the relatively simple structure can close the gap and prevent entry of contaminants, reducing the number of times of sterilization with an autoclave, etc., which is cumbersome and can degrade the equipment. In addition, the possibility of contaminants entering the tube and control unit can be reduced.
[0033]
Moreover, the cross-sectional shape of the contact piece of the sealing member is a tapered shape in which the thickness is reduced toward the portion in contact with the cutting tool or the cutting tool holder. Therefore, the contact load at the contact portion can be reduced, and generation of contact sound and vibration can be prevented.
[0034]
Further, the contact piece of the seal member is pushed outward by the pressure of the working gas inside the head that rises when the cutting tool is operated to leave the cutting tool or the cutting tool holder, and closes when the cutting tool is inoperative to close the gap. Since the sealing member is configured to be closed, the seal member does not come into contact with the cutting tool being operated, so that no wear due to contact occurs particularly in the case where the cutting tool rotates. Moreover, since gas is expelled from the gap during operation, contaminants do not enter the head, the operating sound leaking from the head is reduced, and the gap is closed after the operation is stopped. Intrusion is reliably prevented.
[0035]
In addition, if at least a portion of the contact piece of the seal member that contacts the cutting tool or the cutting tool holder is made of a material having a low coefficient of friction, wear due to contact with a cutting tool rotating at high speed is less likely to occur. .
[0036]
Further, the contact portion between the contact piece and the cutting tool or cutting tool holder of the seal member because the set only a cooling means for cooling by water, such as a cutting tool in the rotating heating is mitigated fast contact portion Even if touched, it becomes difficult to wear.
[0037]
In addition, in the case where each of the sealing member and the cutting machine body is provided with an engaging portion for making the sealing member detachable from the cutting machine main body, the sealing member can be easily attached and detached. If one of them is configured to be elastically deformable, the attaching / detaching operation is further facilitated.
[0038]
In addition, when the sealing member is formed integrally with the cover member that covers the main body of the cutting machine, contamination of not only the inside of the head but also the outer surface of the main body of the cutting machine is prevented, so that the number of times of sterilization can be reduced. Management becomes easier.
[0039]
In addition, when the present invention is applied to a medical air turbine handpiece or a medical micromotor handpiece, the possibility of infection in, for example, dental practice is greatly reduced, and safety during medical care is improved.
[0040]
The sealing member for a medical cutting instrument according to the present invention is used in the above-described cutting instrument, is configured as described above, and can exhibit the above-described effects by being mounted on the cutting instrument.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a head according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the sealing member according to the above.
FIG. 3 is an operation explanatory diagram of the above.
FIG. 4 is a cross-sectional view of a head in another embodiment.
FIG. 5 is a cross-sectional view of a head according to another embodiment.
FIG. 6 is a cross-sectional view of a head according to another embodiment.
FIG. 7 is a side view of a cutting instrument in another embodiment.
FIG. 8 is a cross-sectional view of the head of the above.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Handpiece main body 1g Nozzle 2 Head 2d Spindle 2f Engagement groove 3 Cutting tool 3a Shaft 4 Seal member 4a Engagement part 4c Contact piece 5 Crevice 6 Cover member 6a Seal member 6d Contact piece

Claims

A seal member is provided in a portion where an annular gap is formed around a cutting tool or a cutting tool holder mounted on the head, and a contact piece that contacts the cutting tool or the cutting tool holder and closes the gap is provided as the sealing member. The contact piece is formed of an elastic body at least in contact with the cutting tool or the cutting tool holder of the contact piece, and the contact piece is caused by the pressure of the working gas inside the head that rises when the cutting tool is operated. A medical cutting instrument characterized in that it is configured to be pushed outward and away from a cutting tool or a cutting tool holder, and to close when the cutting tool is inoperative to close the gap .

A seal member is provided in a portion where an annular gap is formed around a cutting tool or a cutting tool holder mounted on the head, and a contact piece that contacts the cutting tool or the cutting tool holder and closes the gap is provided as the sealing member. And at least a portion of the contact piece that contacts the cutting tool or the cutting tool holder is formed of an elastic body, and a portion where the contact piece and the cutting tool or the cutting tool holder contact each other is water. A medical cutting instrument comprising a cooling means for cooling by means of the above .

The medical cutting instrument according to claim 1 or 2 , wherein the cross-sectional shape of the contact piece is a taper shape with a thickness decreasing toward a portion that contacts the cutting tool or the cutting tool holder.

The medical cutting instrument according to any one of claims 1 to 3, wherein at least a portion of the contact piece that contacts the cutting tool or the cutting tool holder is made of a material having a low friction coefficient.

The medical cutting instrument according to any one of claims 1 to 4 , wherein engagement portions for making the seal member detachable from the cutting instrument main body are provided in the seal member and the cutting instrument main body, respectively.

The medical cutting instrument according to claim 5 , wherein at least one of the engaging portions is elastically deformable.

The medical device according to any one of claims 1 to 6, further comprising a cover member that covers a main body of the cutting instrument, and a seal member that is integrally formed so as to surround a cutting tool through hole provided in the cover member. Cutting instrument.

The medical cutting instrument according to any one of claims 1 to 7 , wherein the cutting instrument is a medical air turbine handpiece or a medical micromotor handpiece.

A sealing member which is attached to a portion where an annular gap is formed around a cutting tool or a cutting tool holder attached to a head of a cutting machine and prevents foreign matter from entering the head, contact piece for closing the gap in contact with the tool holder is formed in an annular shape, at least the cutting tool or the portion in contact with the cutting tool holder of the contact piece is an elastic body Rutotomoni, the contact piece, the cutting A sealing member for a medical cutting instrument, which is configured to be pushed outward by the pressure of a working gas inside the head that rises when the tool is operated, and to close and close the gap when the cutting tool is inoperative .

10. The sealing member for a medical cutting instrument according to claim 9 , wherein the cross-sectional shape of the contact piece is a taper shape with a thickness decreasing as it approaches a portion that contacts the cutting tool or the cutting tool holder.

The sealing member for a medical cutting instrument according to claim 9 or 10 , wherein at least a portion of the contact piece that contacts the cutting tool or the cutting tool holder is made of a material having a low friction coefficient.

The medical cutting instrument sealing member according to any one of claims 9 to 11 , wherein an engaging portion is provided to be attachable to and detachable from the cutting instrument main body.

The medical cutting instrument sealing member according to claim 12 , wherein the engaging portion is elastically deformable.

14. The sealing member for a medical cutting instrument according to claim 13 , wherein the engaging portion is a rubber O-ring shape.

15. The medical cutting instrument according to claim 9 , wherein the contact piece is formed integrally with the cover member so as to surround a cutting tool through hole provided in the cover member covering the main body of the cutting instrument. Seal member.