JP2004090170A

JP2004090170A - Material guiding device and automatic lathe

Info

Publication number: JP2004090170A
Application number: JP2002255129A
Authority: JP
Inventors: Osamu Washimine; 鷲峰　修
Original assignee: Citizen Watch Co Ltd
Current assignee: Citizen Watch Co Ltd
Priority date: 2002-08-30
Filing date: 2002-08-30
Publication date: 2004-03-25
Anticipated expiration: 2022-08-30
Also published as: JP4201553B2

Abstract

<P>PROBLEM TO BE SOLVED: To accurately adjust radial dimension of a material support section of a guide bush without relying on skill or experience of a worker, in a material guiding device of an automatic lathe. <P>SOLUTION: The material guiding device 10 comprises: the guide bush 16 having a hollow cylindrical material support section 14 deformable radially and elastically; a support body 18 for supporting the guide bush 16; an operating mechanism 20 for radially and elastically shifting the material support section 14 of the guide bush 16; and an adjusting mechanism 22 for adjusting the radial dimension of the material support section 14 via the operating mechanism 20. The adjusting mechanism 22 has a detecting section 64 disposed related to the guide bush 16 and the support body 18. The detecting section 64 detects thrust force applied to the guide bush 16 in the axial direction of the guide bush 16. The adjusting mechanism 22 further has a driving section 66 for driving the operating mechanism 20 and a control section 68 for controlling the driving section 66 for suitably adjusting the radial dimension of the material support section 14 based on the detected thrust force of the detecting section 64. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、加工中の被加工素材をその加工部位近傍で支持する素材ガイド装置に関する。さらに本発明は、素材ガイド装置を備えた自動旋盤に関する。
【０００２】
【従来の技術】
ＮＣ旋盤等の、種々の自動旋削加工を実施できる工作機械（本明細書で自動旋盤と総称する）において、工具による加工作業位置の近傍で旋盤機台上に設置され、主軸に把持された棒状の被加工素材（以下、棒材と称する）を、その先端の加工部位の近傍で支持する補助支持装置としての素材ガイド装置を備えたものは知られている。素材ガイド装置は、一般に、径方向へ弾性変位可能な中空筒状の素材支持部を有するガイドブッシュと、ガイドブッシュの素材支持部を径方向へ弾性変位させる作動機構とを備えて構成される。
【０００３】
従来の素材ガイド装置は、高速回転する棒材に対して固定的に配置される固定型ガイドブッシュを備えたものと、棒材と共に高速回転できる回転型ガイドブッシュを備えたものとが、適宜選択して使用されている。いずれの構成でも、素材ガイド装置はガイドブッシュの素材支持部によって、旋削加工中に棒材をその加工部位に振れが生じないように支持し、それにより製品を高精度に加工成形することを可能にする。また、棒材を把持した主軸が軸線方向へ送り運動できる構成を有する自動旋盤において、素材ガイド装置は、固定型及び回転型のいずれのガイドブッシュを備えたものにおいても、素材支持部に棒材を心出し支持（すなわち棒材軸線を回転軸線に合致させるように支持）した状態で、主軸の軸線方向移動により送られる棒材を軸線方向へ正確に案内しつつ支持できるようになっている。
【０００４】
この種の素材ガイド装置においては、棒材の心出し支持と軸線方向案内支持との双方を所要水準で達成できるようにするために、加工対象の棒材を加工作業開始前にガイドブッシュに挿入し、手作業で作動機構を操作することにより、ガイドブッシュの素材支持部を弾性変位させてその内径寸法を加工対象棒材（丸棒、角棒）の外径寸法に合わせて調整していた。一般にこのような事前調整作業は、時間を消費するものであり、調整精度を高めるためには作業者の熟練を必要とする。そこで従来、ガイドブッシュの素材支持部の径方向寸法を、作動機構を介して自動的に調整するための調整機構を備えた素材ガイド装置が提案されている（特開平７−３２８８０４号公報参照）。
【０００５】
この公知の素材ガイド装置では、調整機構は、作動機構を駆動するサーボモータと、トルク監視下でサーボモータの動作を制御する制御手段とを備える。この調整機構によりガイドブッシュの素材支持部の径方向寸法を自動調整する際には、まず、加工対象の棒材をガイドブッシュに挿通した状態でサーボモータを起動し、素材支持部を漸進的に弾性変位させて棒材を支持させる。そして、サーボモータのトルクが所定閾値を超えたときにサーボモータを停止して、素材支持部を仮の棒材支持位置に保持する。さらにその状態で、棒材を強固に把持した主軸を軸線方向送り（又は回転）運動させて、棒材と素材支持部との間に生じる摩擦抵抗を、主軸の送り（又は回転）用サーボモータのトルク監視によって測定する。そして、測定した摩擦抵抗（トルク）値が予め定めた範囲内にあるときには、素材支持部の径方向寸法（或いは素材支持部と棒材との間の微小隙間）が適正に調整できたものとして、事前調整作業を終了する。他方、測定した摩擦抵抗が予め定めた範囲外のときは、サーボモータを正回転又は逆回転させて、トルク監視下での隙間調整を繰り返して実施する。
【０００６】
【発明が解決しようとする課題】
従来の素材ガイド装置において、ガイドブッシュの素材支持部の径方向寸法を高精度に調整するためには、加工対象棒材の外径寸法だけでなく、棒材材質や加工中の主軸回転数をも勘案して、素材支持部と加工対象棒材との間に最適な摩擦抵抗が生じる状態にする必要がある。したがって、手作業で作動機構を操作してガイドブッシュの素材支持部と棒材との微小隙間を調整する従来の隙間調整方法では、作業者の経験に裏打ちされた高度な技術が必要となり、作業者が替わる度に調整結果にばらつきが生じる傾向があった。また、前述した公知の素材ガイド装置の隙間調整機構は、主軸の送り（又は回転）用サーボモータのトルク監視により棒材と素材支持部との間に生じる摩擦抵抗を測定して、最適な摩擦抵抗が生じるようにガイドブッシュの素材支持部を寸法調整する構成であるから、サーボモータのトルク変動に影響を与える他の要因（例えば主軸の移動に伴う負荷の増減）を排除しない限り、摩擦抵抗を正確に測定することは困難であり、結果として素材支持部の径方向寸法を高精度に調整することが困難であった。
【０００７】
本発明の目的は、自動旋盤に設置される素材ガイド装置において、作業者の熟練や経験に依存せずに、ガイドブッシュの素材支持部の径方向寸法を高精度に事前調整できる素材ガイド装置を提供することにある。
本発明のさらに他の目的は、そのような素材ガイド装置を備えた高性能の自動旋盤を提供することにある。
【０００８】
【課題を解決するための手段】
上記目的を達成するために、請求項１に記載の発明は、径方向へ弾性変位可能な中空筒状の素材支持部を有するガイドブッシュと、ガイドブッシュを支持する支持体と、ガイドブッシュの素材支持部を径方向へ弾性変位させる作動機構と、作動機構を介して素材支持部の径方向寸法を調整する調整機構とを具備する素材ガイド装置において、調整機構は、ガイドブッシュと支持体とに関連して設けられ、ガイドブッシュにその軸線方向へ負荷される推力を検出する検出部を具備し、検出部が検出した推力に基づいて、素材支持部の径方向寸法を調整できるようにすること、を特徴とする素材ガイド装置を提供する。
【０００９】
請求項２に記載の発明は、請求項１に記載のガイドブッシュにおいて、調整機構は、作動機構を駆動する駆動部と、検出部が検出した推力に基づいて駆動部を制御する制御部とをさらに具備する素材ガイド装置を提供する。
【００１０】
請求項３に記載の発明は、請求項２に記載のガイドブッシュにおいて、制御部は、被加工素材を加工する種々の加工工程の各々に関連して予め設定した推力許容値と検出部が検出した推力との比較に基づき、駆動部を制御する素材ガイド装置を提供する。
【００１１】
請求項４に記載の発明は、請求項１〜３のいずれか１項に記載のガイドブッシュにおいて、検出部は、ガイドブッシュ及び支持体に関連して軸線方向へ相対移動可能な二部分の間に介在する荷重変換素子を具備する素材ガイド装置を提供する。
【００１２】
請求項５に記載の発明は、請求項１〜３のいずれか１項に記載のガイドブッシュにおいて、検出部は、ガイドブッシュ及び支持体に関連して軸線方向へ相対移動可能な二部分の間に介在する圧電素子を具備する素材ガイド装置を提供する。
【００１３】
請求項６に記載の発明は、請求項１〜５のいずれか１項に記載の素材ガイド装置を、被加工素材の加工作業位置近傍に設置してなる自動旋盤を提供する。
【００１４】
【発明の実施の形態】
以下、添付図面を参照して、本発明の実施の形態を詳細に説明する。全図面に渡り、対応する構成要素には共通の参照符号を付す。
図面を参照すると、図１は、本発明の一実施形態による素材ガイド装置１０を示す断面図、図２は、素材ガイド装置１０を備えた本発明の一実施形態による自動旋盤１２の、主要部を示す一部切欠正面図である。素材ガイド装置１０は、自動旋盤１２において、主軸に把持された棒材Ｗをその先端の加工部位の近傍で支持する補助支持装置として機能する。
【００１５】
素材ガイド装置１０は、径方向へ弾性変位可能な中空筒状の素材支持部１４を有するガイドブッシュ１６と、ガイドブッシュ１６を支持する支持体１８と、ガイドブッシュ１６の素材支持部１４を径方向へ弾性変位させる作動機構２０と、作動機構２０を介して素材支持部１４の径方向寸法を調整する調整機構２２とを備えて構成される。ガイドブッシュ１６は、自動旋盤１２での旋削加工工程中に、素材支持部１４に支持した高速回転する加工対象棒材Ｗに対して、支持体１８上に固定的に配置される固定型ガイドブッシュの構成を有する。
【００１６】
ガイドブッシュ１６の素材支持部１４は、支持対象の棒材Ｗの中心軸線に合致する中心軸線１４ａを有して、棒材Ｗを軸線方向送り可能に心出し支持（すなわち棒材軸線を旋削中の回転軸線に合致させるように支持）する。その目的で、素材支持部１４は、中心軸線１４ａを基準として内径寸法を弾性的に変更可能なすり割り構造を有し、複数（例えば３個）のスリット２４によって分割形成された複数（例えば３個）の縦割片２６が、径方向へ板ばね状に弾性変位できるようになっている。それら縦割片２６は、それぞれの内面が互いに協働して、棒材Ｗを心出し支持する実質的円筒状の素材支持面２８を形成するとともに、それぞれの外面に設けたテーパ面が互いに協働して、素材支持部１４を径方向内方へ変位させるための外力を受ける円錐台状の圧力受け面３０を形成する。
【００１７】
素材支持部１４は、圧力受け面３０に一様に外力を加えて複数の縦割片２６を径方向内方へ弾性的に撓ませることにより、素材支持面２８の内径寸法を縮小（すなわち縮径）できる。その状態から、素材支持部１４への外力が弱められると、各縦割片２６が径方向外方へ弾性的に復元して素材支持面２８の内径寸法が拡大（すなわち拡径）する。このようにガイドブッシュ１６では、素材支持部１４に負荷する外力を調節することによって、素材支持面２８の径寸法を調整することができる。
【００１８】
ガイドブッシュ１６はさらに、素材支持部１４から共軸状に軸線方向へ一体的に延設される中空筒状の基部３２を備える。基部３２の、素材支持部１４から離れた軸線方向後端（図１で右端）領域には、その外周面に沿って雄ねじ部分３４が形成される。また、素材支持部１４と雄ねじ部分３４との間には、基部３２の外周面に沿って、任意の中心角度位置で軸線方向へ延びる１条のキー溝３６が形成される。
【００１９】
支持体１８は、ガイドブッシュ１６を同心状に収容して支持する中空筒状のスリーブ部材３８と、スリーブ部材３８を静的に支持するコラム４０とを備える。スリーブ部材３８には、その軸線方向中央領域で任意の中心角度位置に、スリーブ内外周面から両端部分を径方向へ突出させる回り止め４２が設置される。スリーブ部材３８は、回り止め４２の内方端をガイドブッシュ１６のキー溝３６に嵌入した状態で、ガイドブッシュ１６を、径方向へのがたつき無く軸線方向へ摺動可能に、かつ相対回転不能に支持する。スリーブ部材３８の内周面の軸線方向前端領域には、ガイドブッシュ１６の圧力受け面３０に係合可能な円錐台状の作用面４４が形成される。作用面４４は、ガイドブッシュ１６の素材支持部１４を径方向へ弾性変位させるための外力を圧力受け面３０に負荷する加圧面として機能する。
【００２０】
コラム４０には、筒状の取付穴４６が貫通形成され、取付穴４６の任意の中心角度位置に、軸線方向へ延びる１条のキー溝４８が設けられる。スリーブ部材３８は、回り止め４２の外方端をコラム４０のキー溝４８に嵌入した状態で、コラム４０の取付穴４６に、径方向へのがたつき無く軸線方向へ摺動可能に、かつ相対回転不能に取り付けられる。スリーブ部材３８の外周面には、軸線方向前端（図１で左端）近傍に外方へ突出するフランジ部分５０が形成されるとともに、軸線方向後端領域に雄ねじ部分５２が形成される。雄ねじ部分５２には、対応の雌ねじを有する取付ナット５４が螺着される。スリーブ部材３８は、フランジ部分５０と取付ナット５４との間にコラム４０を挟持した状態で、取付穴４６に取り付けられる。
【００２１】
作動機構２０は、スリーブ部材３８の軸線方向後端側に同心状に設置される中空筒状の作動部材５６を備える。作動部材５６は、その軸線方向前端（図で左端）領域に、ガイドブッシュ１６の基部３２の後端に設けた雄ねじ部分３４に螺合する雌ねじ部分５８が形成されるとともに、軸線方向後端領域に、径方向外方へ円板状に延出するプーリ部分６０が形成される。作動部材５６は、その軸線方向前端領域をスリーブ部材３８の軸線方向後端領域に同心状に挿入した状態で、雌ねじ部分５８を雄ねじ部分３４に螺合させてガイドブッシュ１６に作用的に連結される。なお、作動部材５６とコラム４０との間には、スリーブ部材３８と取付ナット５４との螺合部分を保護するためのカバー６２が設置されている。
【００２２】
上記構成において、作動部材５６をスリーブ部材３８に対し軸線方向へ固定した状態で所望方向に回動させると、雄ねじ部分３４と雌ねじ部分５８との螺合及びキー溝３６と回り止め４２との係合によって形成される送りねじ構造により、ガイドブッシュ１６がスリーブ部材３８の内側で軸線方向へ移動する。それにより、ガイドブッシュ１６の圧力受け面３０とスリ−ブ部材３８の作用面４４との間に生じる相互圧力が変動し、素材支持部１４の内径寸法が変化する。なお、図示実施形態では、作動部材５６は、その軸線方向前端面５６ａを、スリーブ部材３８の内周面に沿って形成した肩面３８ａに当接するまで、雌ねじ部分５８がガイドブッシュ１６の雄ねじ部分３４にねじ込まれており、その状態で、スリーブ部材３８に対する作動部材５６の軸線方向前方移動が阻止されている。
【００２３】
本発明の特徴的構成として、調整機構２２は、ガイドブッシュ１６と支持体１８とに関連して設けられる検出部６４を備える。検出部６４は、ガイドブッシュ１６にその軸線方向へ負荷される推力を検出し、検出推力に基づいて、ガイドブッシュ１６の素材支持部１４の径方向寸法を適正に調整できるようにする。その目的で、調整機構２２はさらに、作動機構２０を駆動する駆動部６６と、検出部６４が検出した推力に基づいて駆動部６６を制御する制御部６８とを備える。
【００２４】
図示実施形態では、検出部６４は、ガイドブッシュ１６及び支持体１８に関連して軸線方向へ相対移動可能な二部分の間に介在する荷重変換素子（ロードセル）７０から構成される。荷重変換素子７０は、環状の弾性体構造を有し、スリーブ部材３８の軸線方向後端領域を同心状に囲繞して、取付ナット５４（軸線方向可動部分）とコラム４０（固定部分）との間に挿入配置される。この状態で、取付ナット５４とコラム４０とから荷重変換素子７０に圧力が加わると、荷重変換素子７０が弾性変形し、その機械的歪みを電気信号（抵抗値変化）に変換して制御部６８に出力する。なお、荷重変換素子７０は、それ自体の弾性変形範囲でコラム４０に対するスリーブ部材３８の僅かな軸線方向移動を許容するが、その弾性変形態様は、取付ナット５４とコラム４０との間に介在してスリーブ部材３８をコラム４０に対し軸線方向へ実質的静止状態に支持できる程度のものである。
【００２５】
荷重変換素子７０から出力された電気信号はすなわち検出部６４が検出した上記推力に対応するので、制御部６８は、この電気信号を演算処理して、必要に応じて駆動部６６に所要の駆動動作を指令する。そして駆動部６６は、制御部６８からの指令に基づき、作動部材５６を所要の回転方向及び回転角度に駆動し、それによりガイドブッシュ１６をスリーブ部材３８の内側で軸線方向へ移動させて、素材支持部１４の内径寸法を変化させる。
【００２６】
上記した調整機構２２による素材支持部１４の径方向寸法調整手順を、図２に示す自動旋盤１２に関連してさらに詳述する。
自動旋盤１２は、機台７２上に軸線方向移動可能に設置される主軸７４を備える。主軸７４は、主軸台７６に回転自在に収容され、加工対象棒材Ｗを強固に把持して、図示しない主軸駆動源により回転駆動される。主軸台７６は、機台７２の上面に設置されたリニアガイド装置７８に沿って、図示しない送り駆動源により、主軸７４の回転軸線方向へ送り運動できるようになっている。素材ガイド装置１０の支持体１８を構成するコラム４０は、機台７２の上面に一体的に立設され、ガイドブッシュ１６を、その素材支持部１４の中心軸線１４ａが主軸７４の回転軸線に合致する位置に支持する。この位置で、ガイドブッシュ１６は、主軸７４に把持された棒材Ｗの加工部位近傍を心出し支持して、機台７２上に設定された工具８０による加工作業位置に棒材Ｗの加工部位を位置決めする。
【００２７】
図示実施形態では、素材ガイド装置１０の調整機構２２の駆動部６６として、コラム４０上にサーボモータ６６が設置される。サーボモータ６６の出力軸にはプーリ８２が固定され、プーリ８２と作動部材５６のプーリ部分６０との間に、動力伝達用のベルト８４が張設される。また、制御部６８は、自動旋盤１２の主軸７４や刃物台（図示せず）の動作を制御する制御装置（例えばＮＣ装置）に組み込んで構成されるものとするが、別の制御装置を使用することもできる。
【００２８】
上記構成を有する自動旋盤１２においては、棒材Ｗの加工プログラムを開始する前の予備段階として、素材ガイド装置１０におけるガイドブッシュ１６の素材支持部１４の径方向寸法を、棒材Ｗの外径寸法に合わせて調整する。この事前調整作業に際しては、まず、素材支持部１４に径方向内方への外力を加えない状態で、主軸７４に把持した棒材Ｗを、主軸台７６の軸線方向送り運動により、作動部材５６側からガイドブッシュ１６内に挿入して素材支持部１４に挿通する。その状態から、サーボモータ６６を起動して、作動部材５６をその雌ねじ部分５８がガイドブッシュ１６の雄ねじ部分３４にねじ込まれる方向へ回動させる。それにより、ガイドブッシュ１６がスリーブ部材３８に対し軸線方向後方へ移動して、ガイドブッシュ１６の圧力受け面３０がスリーブ部材３８の作用面４４に押付けられ、その結果、ガイドブッシュ１６の素材支持部１４が一様に径方向内方へ弾性変位して、素材支持面２８が棒材Ｗの外周面に当接される。この間、制御部６８はサーボモータ６６のトルクを継続して監視し、トルクが予め記憶した所定閾値を超えたときにサーボモータ６６を停止して、素材支持部１４を仮の棒材支持位置に保持する。
【００２９】
次に、ガイドブッシュ１６の素材支持部１４を仮の棒材支持位置に保持した状態で、棒材Ｗを強固に把持した主軸７４を軸線方向前方（すなわち素材ガイド装置１０に接近する方向）へ送り運動させる。このとき、素材支持部１４の素材支持面２８と棒材Ｗの外周面との間に生じる摩擦抵抗に起因して、ガイドブッシュ１６に軸線方向前方への推力が負荷される。この推力は、ガイドブッシュ１６の雄ねじ部分３４と作動部材５６の雌ねじ部分５８との螺合、及び作動部材５６の軸線方向前端面５６ａとスリーブ部材３８の肩面３８ａとの衝合によって、スリーブ部材３８に軸線方向前方への推力として伝達される。さらにこの推力は、スリーブ部材３８に螺着した取付ナット５４とコラム４０との間に介在する荷重変換素子７０に圧力として伝達される。この圧力により、荷重変換素子７０は弾性変形し、その機械的歪みを電気信号に変換して制御部６８に出力する。
【００３０】
制御部６８は、荷重変換素子７０から出力された電気信号を演算処理して、ガイドブッシュ１６に負荷された推力（又は摩擦抵抗）が、予め記憶した所定の許容範囲内に有るか否かを判断する。そして、推力（又は摩擦抵抗）が許容範囲に有ると判断したときは、素材支持部１４の径方向寸法（或いは素材支持部１４と棒材Ｗとの間の微小隙間）が仮の棒材支持位置で適正に調整できているものとして、事前調整作業を終了する。他方、ガイドブッシュ１６に負荷された推力又は摩擦抵抗が許容範囲に無いと判断したときは、サーボモータ６６を正回転又は逆回転させて、素材支持部１４の径方向寸法を再調整し、次いで棒材Ｗの軸線方向移動によりガイドブッシュ１６に負荷される推力の検出及び許容判断を再度実施する。ここで例えば、サーボモータ６６の出力軸の回転角度を予め定めたパルス数で制御すれば、スリーブ部材３８に対するガイドブッシュ１６の軸線方向移動量及び素材支持部１４の径方向変位量を、段階的に微調整することができる。このようにして、ガイドブッシュ１６の素材支持部１４と加工対象棒材Ｗの外周面との間に、許容範囲の推力（又は摩擦抵抗）を生じる所望の微小隙間を確保できる。
【００３１】
上記構成を有する素材ガイド装置１０では、荷重変換素子７０からなる検出部６４は、素材支持部１４の素材支持面２８と棒材Ｗの外周面との間に生じる摩擦抵抗に起因してガイドブッシュ１６に負荷される軸線方向前方への推力を、ガイドブッシュ１６と支持体１８との間で検出するものであるから、主軸駆動用サーボモータのトルク監視により棒材と素材支持部との間の摩擦抵抗を測定する従来技術と異なり、他の要因による主軸駆動用サーボモータのトルク変動に影響されることなく、推力を正確に検出することができる。その結果、素材ガイド装置１０によれば、ガイドブッシュ１６の素材支持部１４の径方向寸法を高精度に事前調整することが可能になる。
【００３２】
また、制御部６８は、荷重変換素子７０の検出信号を処理して、検出した推力と予め定めた推力許容値とを比較した結果に基づき、作動部材５６を動作させてガイドブッシュ１６の素材支持部１４の径方向寸法を調整するようにしたから、加工対象棒材Ｗの外径寸法、材質及び加工中の主軸回転数等の固有パラメータから導き出される素材支持部１４と棒材Ｗとの間の最適な摩擦抵抗（又は推力）を、許容範囲として予め設定して制御部６８に記憶しておけば、作業者の熟練や経験に依存せずに、素材支持部１４の径方向寸法を高精度に調整できる。
【００３３】
この場合、加工対象棒材Ｗの加工プログラムに含まれる種々の加工工程の各々に関連して、摩擦抵抗（又は推力）の許容範囲を予め設定しておくことが好ましい。例えば、棒材Ｗを軸線方向へ送りながらの通常の旋削加工工程に加えて、棒材Ｗを静止させた状態での回転工具による二次的加工工程を実施可能な多機能型の自動旋盤においては、素材ガイド装置１０は、通常の旋削加工工程では棒材送り動作を妨げることなく棒材Ｗを案内支持でき、また二次的加工工程では切削抵抗に抗して棒材Ｗを強固に固定的に支持できるように、ガイドブッシュ１６の素材支持部１４の径方向寸法を調整できることが有利である。
【００３４】
図３は、素材ガイド装置１０の変形例を示す。この素材ガイド装置１０では、調整機構２２の検出部６４として、スリーブ部材３８の軸線方向後端側で取付ナット５４とコラム４０との間に挿入配置される荷重変換素子７０に加えて、スリーブ部材３８の軸線方向前端側でフランジ部分５０（軸線方向可動部分）とコラム４０（固定部分）との間に挿入配置される荷重変換素子８６を装備している。荷重変換素子８６は、荷重変換素子７０と同様の環状の弾性体構造を有し、スリーブ部材３８の軸線方向前端領域を同心状に囲繞して配置される。この状態で、フランジ部分５０とコラム４０とから荷重変換素子８６に圧力が加わると、荷重変換素子８６が弾性変形し、その機械的歪みを電気信号（抵抗値変化）に変換して制御部６８に出力する。
【００３５】
上記構成では、ガイドブッシュ１６の素材支持部１４を前述した仮の棒材支持位置に保持した状態で、棒材Ｗを強固に把持した主軸７４を軸線方向後方（すなわち素材ガイド装置１０から離れる方向）へ送り運動させたときに、素材支持部１４の素材支持面２８と棒材Ｗの外周面との間に生じる摩擦抵抗に起因してガイドブッシュ１６に負荷される軸線方向後方への推力が、ガイドブッシュ１６の圧力受け面３０とスリーブ部材３８の作用面４４との衝合によって、スリーブ部材３８に軸線方向後方への推力として伝達される。そしてこの推力は、スリーブ部材３８のフランジ部分５０とコラム４０との間に介在する荷重変換素子８６に圧力として伝達される。
【００３６】
このように、上記変形例によれば、ガイドブッシュ１６の素材支持部１４の径方向寸法を調整するための主要データである前述した軸線方向推力を、棒材Ｗを素材支持部１４に対して軸線方向前方へ移動させたときだけでなく、軸線方向後方へ移動させたときにも、検出部６４によって検出することができる。したがって、加工対象棒材Ｗの略全長に渡って、ガイドブッシュ１６の素材支持部１４と棒材Ｗの外周面との間の微小隙間を最適化することができる。
【００３７】
図４は、素材ガイド装置１０の他の変形例を示す。この素材ガイド装置１０では、調整機構２２の検出部６４として、スリーブ部材３８の肩面３８ａ（固定部分）と作動部材５６の軸線方向前端面５６ａ（軸線方向可動部分）との間に挿入配置される荷重変換素子８８を装備している。荷重変換素子８８は、前述した荷重変換素子７０と同様の環状の弾性体構造を有し、ガイドブッシュ１６の軸線方向後端領域を同心状に囲繞して配置される。この状態で、スリーブ部材３８と作動部材５６とから荷重変換素子８８に圧力が加わると、荷重変換素子８８が弾性変形し、その機械的歪みを電気信号（抵抗値変化）に変換して制御部６８に出力する。なおスリーブ部材３８は、取付ナット５４により、コラム４０に対し軸線方向へ強固に固定して設置される。
【００３８】
上記構成では、ガイドブッシュ１６の素材支持部１４を前述した仮の棒材支持位置に保持した状態で、棒材Ｗを強固に把持した主軸７４を軸線方向前方へ送り運動させたときに、素材支持部１４の素材支持面２８と棒材Ｗの外周面との間に生じる摩擦抵抗に起因してガイドブッシュ１６に負荷される軸線方向前方への推力が、雄ねじ部分３４と雌ねじ部分５８との螺合によって作動部材５６に軸線方向前方への推力として伝達される。そしてこの推力は、スリーブ部材３８と作動部材５６との間に介在する荷重変換素子８８に圧力として伝達される。このように、上記変形例によっても、図１に示す素材ガイド装置１０と同等の作用効果が奏されることは理解されよう。
【００３９】
本発明に係る素材ガイド装置は、上記した固定型ガイドブッシュを有する構成に限定されず、旋削加工中に高速回転する棒材と共に回転する回転型ガイドブッシュを有する構成とすることもできる。図５は、そのような回転型ガイドブッシュを備えた本発明の他の実施形態による素材ガイド装置９０を示す。なお、素材ガイド装置９０は、ガイドブッシュ１６の支持構造以外は、上記した素材ガイド装置１０と実質的同一の構成を有するので、対応の構成要素には共通する参照符号を付してその説明を省略する。また、素材ガイド装置９０は、前述した素材ガイド装置１０と同様に、図２に示す自動旋盤１２の機台７２上で、工具８０による加工作業位置の近傍に設置できる。
【００４０】
素材ガイド装置９０では、スリーブ部材３８は、軸受装置９２を介して、中空筒状の支持部材９４に回動自在に収容される。支持部材９４は、取付ナット５４を用いて、コラム４０の取付穴４６に、径方向へのがたつき無く軸線方向へ摺動可能に、かつ相対回転不能に取り付けられる。支持部材９４は支持体１８を構成し、軸受装置９２を介して、スリーブ部材３８とガイドブッシュ１６とを一体的に、回転軸線１６ａ（素材支持部１４の中心軸線１４ａと同一）を中心に回動自在に支持する。スリーブ部材３８の外周面の軸線方向後端領域には、被動歯車９６が取り付けられる。被動歯車９６は、図示しない動力伝達機構を介して図示しないガイドブッシュ駆動源に連結され、ガイドブッシュ駆動源により、自動旋盤１２に装備される主軸７４（図２）の回転速度と同一の回転速度で回転駆動される。その結果、自動旋盤１２で旋削加工を実施する際に、被動歯車９６、スリーブ部材３８及びガイドブッシュ１６が、支持部材９４の内側で一体的に、主軸７４の回転速度と同一の回転速度で回転する。
【００４１】
素材ガイド装置９０では、調整機構２２の検出部６４は、支持部材９４の軸線方向前端のフランジ部分９４ａ（軸線方向可動部分）とコラム４０（固定部分）との間、及び支持部材９４の軸線方向後端に螺着した取付ナット５４（軸線方向可動部分）とコラム４０（固定部分）との間にそれぞれ介在する一対の荷重変換素子９８から構成される。各荷重変換素子９８は、図１の荷重変換素子７０と同様の環状の弾性体構造を有し、支持部材９４を同心状に囲繞して配置される。この状態で、支持部材９４又は取付ナット５４とコラム４０とから各荷重変換素子９８に圧力が加わると、荷重変換素子９８が弾性変形し、その機械的歪みを電気信号（抵抗値変化）に変換して制御部６８に出力する。
【００４２】
上記構成では、ガイドブッシュ１６の素材支持部１４を前述した仮の棒材支持位置に保持した状態で、棒材Ｗを強固に把持した主軸７４を軸線方向前方又は後方へ送り運動させたときに、素材支持部１４の素材支持面２８と棒材Ｗの外周面との間に生じる摩擦抵抗に起因してガイドブッシュ１６に負荷される軸線方向前方又は後方への推力が、ガイドブッシュ１６からスリーブ部材３８及び軸受装置９２を介して、支持部材９４及び取付ナット５４とコラム４０との間に介在する荷重変換素子９８のいずれかに圧力として伝達される。このような構成によれば、図３に変形例として示す素材ガイド装置１０と同等の作用効果が奏されることが理解されよう。
【００４３】
本発明に係る素材ガイド装置は、作動機構を手動操作してガイドブッシュの素材支持部を調整する構成にも適用できる。図６は、そのような手動操作型の調整機構を備えた本発明のさらに他の実施形態による素材ガイド装置１００を示す。なお、素材ガイド装置１００は、調整機構の構成以外は、前述した素材ガイド装置１０と実質的同一の構成を有するので、対応の構成要素には共通する参照符号を付してその説明を省略する。また、素材ガイド装置１００は、前述した素材ガイド装置１０と同様に、図２に示す自動旋盤１２の機台７２上で、工具８０による加工作業位置の近傍に設置できる。
【００４４】
素材ガイド装置１００は、作動機構２０として、図１に示すプーリ部分６０を有する作動部材５６の替わりに、軸線方向後端で径方向へ延長される端板部分１０２を備える手動操作用の作動部材５６を備える。また、作動機構２０を介してガイドブッシュ１６の素材支持部１４の径方向寸法を調整する調整機構２２として、ガイドブッシュ１６と支持体１８とに関連して設けられる検出部６４と、検出部６４の検出結果を作業者に知らせる制御部６８とが装備される。検出部６４は、ガイドブッシュ１６にその軸線方向へ負荷される推力を検出し、作業者が、制御部６８を介してその検出推力を知ることにより、手作業で、ガイドブッシュ１６の素材支持部１４の径方向寸法を適正に調整できるようにする。
【００４５】
図示実施形態では、検出部６４は、ガイドブッシュ１６及び支持体１８に関連して軸線方向へ相対移動可能な二部分の間に介在する圧電素子１０４から構成される。圧電素子１０４は、中空筒状の構造を有し、コラム４０の取付穴４６を同心状に囲繞して、作動部材５６の端板部分１０２（軸線方向可動部分）とコラム４０（固定部分）との間に固定配置される。この状態で、作動部材５６の端板部分１０２とコラム４０とから圧電素子１０４に圧力が加わると、圧電素子１０４がその機械的歪みを電気信号（電圧）に変換して制御部６８に出力する。制御部６８は、その電気信号を演算処理して、例えば図示しないディスプレイ装置等に圧電素子１０４による検出結果を表示する。
【００４６】
上記構成では、ガイドブッシュ１６の素材支持部１４を前述した仮の棒材支持位置に保持した状態で、棒材Ｗを強固に把持した主軸７４を軸線方向前方又は後方へ送り運動させたときに、素材支持部１４の素材支持面２８と棒材Ｗの外周面との間に生じる摩擦抵抗に起因してガイドブッシュ１６に負荷される軸線方向前方又は後方への推力が、ガイドブッシュ１６から作動部材５６に伝達され、さらに作動部材５６とコラム４０との間に介在する圧電素子１０４に軸線方向への圧力又は引張力（すなわち径方向圧力）として伝達される。
【００４７】
作業者は、制御部６８で知らされた圧電素子１０４による検出結果を参照して、ガイドブッシュ１６に負荷された推力（又は摩擦抵抗）が、予め設定した所定の許容範囲内に有るか否かを判断する。そして、推力（又は摩擦抵抗）が許容範囲に有ると判断したときは、素材支持部１４の径方向寸法（或いは素材支持部１４と棒材Ｗとの間の微小隙間）が仮の棒材支持位置で適正に調整できているものとして、事前調整作業を終了する。他方、ガイドブッシュ１６に負荷された推力又は摩擦抵抗が許容範囲に無いと判断したときは、作動部材５６を手作業で正回転又は逆回転させて、素材支持部１４の径方向寸法を再調整し、次いで棒材Ｗの軸線方向移動によりガイドブッシュ１６に負荷される推力の検出及び許容判断を再度実施する。なお、予め設定した推力許容値は、随時閲覧可能な書面等に記録しておけばよい。このような構成によっても、図３に変形例として示す素材ガイド装置１０と同等の作用効果が奏されることは理解されよう。
【００４８】
以上、本発明の幾つかの好適な実施形態を説明したが、本発明はそれらに限定されず、様々な修正及び変更を施すことができる。例えば、調整機構の検出部は、支持体上に設置されてガイドブッシュの軸線方向寸法を測定する寸法測定器から構成することもできる。
【００４９】
【発明の効果】
以上の説明から明らかなように、本発明によれば、自動旋盤に設置される素材ガイド装置において、作業者の熟練や経験に依存せずに、ガイドブッシュの素材支持部の径方向寸法を高精度に事前調整することができるようになる。したがって、この素材ガイド装置を搭載した自動旋盤は、高精度旋削加工を実施可能な高性能工作機械となる。
【図面の簡単な説明】
【図１】本発明の一実施形態による素材ガイド装置の構成を一部ブロック図で示す断面図である。
【図２】図１の素材ガイド装置を搭載した本発明の実施形態による自動旋盤の主要部を示す一部切欠正面図である。
【図３】図１の素材ガイド装置の変形例を示す断面図である。
【図４】図１の素材ガイド装置の他の変形例を示す断面図である。
【図５】本発明の他の実施形態による素材ガイド装置の構成を一部ブロック図で示す断面図である。
【図６】本発明のさらに他の実施形態による素材ガイド装置の構成を一部ブロック図で示す断面図である。
【符号の説明】
１０、９０、１００…素材ガイド装置
１２…自動旋盤
１４…素材支持部
１６…ガイドブッシュ
１８…支持体
２０…作動機構
２２…調整機構
３８…スリーブ部材
４０…コラム
５４…取付ナット
５６…作動部材
６４…検出部
６６…駆動部
６８…制御部
７０、８６、８８、９８…荷重変換素子
７２…機台
７４…主軸
１０４…圧電素子[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a material guide device for supporting a material to be processed in the vicinity of a portion to be processed. Further, the present invention relates to an automatic lathe provided with a material guide device.
[0002]
[Prior art]
2. Description of the Related Art In a machine tool such as an NC lathe capable of performing various types of automatic turning (collectively referred to as an automatic lathe in the present specification), a rod-shaped machine installed on a lathe stand near a working position of a tool and held by a spindle. Is provided with a material guide device as an auxiliary support device for supporting a material to be processed (hereinafter, referred to as a bar) in the vicinity of a processing portion at a tip end thereof. The material guide device generally includes a guide bush having a hollow cylindrical material support portion that is elastically displaceable in the radial direction, and an operating mechanism that elastically displaces the material support portion of the guide bush in the radial direction.
[0003]
Conventional material guide devices can be appropriately selected from those having a fixed type guide bush that is fixedly arranged with respect to a high-speed rotating bar and those having a rotary type guide bush that can rotate at a high speed together with the bar. Have been used. In either configuration, the material guide device supports the bar material by the material support part of the guide bush so that there is no run-out in the machined part during turning, so that the product can be processed with high precision To Further, in an automatic lathe having a configuration in which a spindle holding a bar is capable of feeding in the axial direction, the material guide device is provided with a bar supporting member in a material supporting portion, regardless of whether the device has a fixed type or a rotary type guide bush. In a state where the rod is centered and supported (that is, the rod axis is aligned with the rotation axis), the rod fed by the axial movement of the main shaft can be supported while being accurately guided in the axial direction.
[0004]
In this type of material guide device, a bar to be machined is inserted into a guide bush before starting a machining operation so that both centering support and axial guide support of the bar can be achieved at required levels. Then, by manually operating the operating mechanism, the material supporting portion of the guide bush is elastically displaced, and the inner diameter is adjusted according to the outer diameter of the bar (round bar, square bar) to be processed. . Generally, such pre-adjustment work is time-consuming, and requires skill of an operator to improve the adjustment accuracy. Therefore, conventionally, a material guide device provided with an adjusting mechanism for automatically adjusting the radial dimension of the material supporting portion of the guide bush via an operating mechanism has been proposed (see Japanese Patent Application Laid-Open No. 7-328804). .
[0005]
In this known material guide device, the adjusting mechanism includes a servomotor that drives the operating mechanism and control means that controls the operation of the servomotor under torque monitoring. When automatically adjusting the radial dimension of the material support of the guide bush by this adjustment mechanism, first, the servo motor is started with the rod to be processed inserted into the guide bush, and the material support is gradually The bar is supported by elastic displacement. Then, when the torque of the servo motor exceeds a predetermined threshold, the servo motor is stopped, and the material support is held at the temporary bar support position. Further, in this state, the spindle that firmly grips the bar is moved in the axial direction (or rotated) to move the spindle, and the frictional resistance generated between the bar and the material supporting portion is reduced by the servomotor for feeding (or rotating) the spindle. It is measured by torque monitoring. When the measured frictional resistance (torque) value is within a predetermined range, it is assumed that the radial dimension of the material supporting portion (or the minute gap between the material supporting portion and the bar) has been properly adjusted. Then, the pre-adjustment work ends. On the other hand, when the measured friction resistance is out of the predetermined range, the servo motor is rotated forward or backward to repeatedly perform the gap adjustment under the torque monitoring.
[0006]
[Problems to be solved by the invention]
In the conventional material guide device, in order to adjust the radial dimension of the material support portion of the guide bush with high accuracy, not only the outer diameter size of the bar material to be machined, but also the material of the bar material and the number of spindle rotations during machining. In consideration of the above, it is necessary to set a state in which an optimal frictional resistance is generated between the material supporting portion and the bar to be processed. Therefore, the conventional gap adjustment method of manually adjusting the minute gap between the material supporting portion of the guide bush and the bar by manually operating the operating mechanism requires advanced technology backed by the experience of the worker, There was a tendency for the adjustment results to vary each time the user changed. In addition, the above-described clearance adjusting mechanism of the known material guide device measures the frictional resistance generated between the bar and the material supporting portion by monitoring the torque of the feed (or rotation) servomotor of the main shaft, and determines the optimal friction. Since the material support of the guide bush is adjusted in size so that the resistance is generated, the frictional resistance must be removed unless other factors that affect the torque fluctuation of the servomotor (for example, increase or decrease of the load due to the movement of the spindle) are eliminated. Is difficult to measure accurately, and as a result, it is difficult to adjust the radial dimension of the material supporting portion with high accuracy.
[0007]
An object of the present invention is to provide a material guide device that can be pre-adjusted with high accuracy in the radial direction of a material support portion of a guide bush without depending on the skill and experience of an operator in a material guide device installed on an automatic lathe. To provide.
Still another object of the present invention is to provide a high-performance automatic lathe provided with such a material guiding device.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a guide bush having a hollow cylindrical material support portion that is elastically displaceable in a radial direction, a support body that supports the guide bush, and a material for the guide bush. In a material guide device including an operation mechanism that elastically displaces a support portion in a radial direction and an adjustment mechanism that adjusts a radial dimension of the material support portion via the operation mechanism, the adjustment mechanism includes a guide bush and a support. A detecting portion provided in association with the guide bush for detecting a thrust applied to the guide bush in an axial direction thereof, so that a radial dimension of the material supporting portion can be adjusted based on the thrust detected by the detecting portion. And a material guide device characterized by the following.
[0009]
According to a second aspect of the present invention, in the guide bush according to the first aspect, the adjusting mechanism includes a driving unit that drives the operating mechanism and a control unit that controls the driving unit based on the thrust detected by the detecting unit. A material guide device further provided.
[0010]
According to a third aspect of the present invention, in the guide bush according to the second aspect, the control unit detects a permissible thrust value and a detection unit set in advance for each of various processing steps of processing the workpiece. A material guide device for controlling a drive unit based on a comparison with the thrust force provided.
[0011]
According to a fourth aspect of the present invention, in the guide bush according to any one of the first to third aspects, the detecting portion is provided between the two portions that are relatively movable in the axial direction in relation to the guide bush and the support. The present invention provides a material guide device including a load conversion element interposed in the material guide device.
[0012]
According to a fifth aspect of the present invention, in the guide bush according to any one of the first to third aspects, the detecting portion is provided between the two portions which are relatively movable in the axial direction in relation to the guide bush and the support. The present invention provides a material guide device including a piezoelectric element interposed therebetween.
[0013]
According to a sixth aspect of the present invention, there is provided an automatic lathe in which the material guide device according to any one of the first to fifth aspects is installed near a processing operation position of a workpiece.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Corresponding components are denoted by the same reference symbols throughout the drawings.
Referring to the drawings, FIG. 1 is a sectional view showing a material guide device 10 according to one embodiment of the present invention, and FIG. 2 is a main part of an automatic lathe 12 according to one embodiment of the present invention equipped with the material guide device 10. FIG. In the automatic lathe 12, the material guide device 10 functions as an auxiliary support device that supports the bar W gripped by the main spindle in the vicinity of a processing portion at the tip thereof.
[0015]
The material guide device 10 includes a guide bush 16 having a hollow cylindrical material support portion 14 capable of elastic displacement in the radial direction, a support 18 supporting the guide bush 16, and a material support portion 14 of the guide bush 16 in the radial direction. An operation mechanism 20 for elastically displacing the material support portion 14 and an adjustment mechanism 22 for adjusting the radial dimension of the material supporting portion 14 via the operation mechanism 20 are provided. The guide bush 16 is a fixed type guide bush that is fixedly disposed on the support 18 with respect to the high-speed rotating bar W to be processed supported by the material support 14 during the turning process by the automatic lathe 12. It has the configuration of
[0016]
The material support portion 14 of the guide bush 16 has a center axis 14a that coincides with the center axis of the bar W to be supported, and supports the bar W in an axially feedable manner (ie, while turning the bar axis). Supported to match the rotation axis of For that purpose, the material supporting portion 14 has a slit structure in which the inner diameter can be elastically changed with respect to the center axis 14a, and a plurality (for example, 3) divided by a plurality of (for example, 3) slits 24. ) Can be elastically displaced radially in the form of a leaf spring. The inner surfaces of the vertical split pieces 26 cooperate with each other to form a substantially cylindrical material support surface 28 for centering and supporting the bar W, and the tapered surfaces provided on the respective outer surfaces cooperate with each other. In operation, a truncated cone-shaped pressure receiving surface 30 receiving an external force for displacing the material support portion 14 inward in the radial direction is formed.
[0017]
The material support portion 14 reduces the inner diameter of the material support surface 28 (that is, reduces the inner diameter of the material support surface 28 by uniformly applying an external force to the pressure receiving surface 30 to elastically bend the plurality of vertical split pieces 26 radially inward). Diameter) In this state, when the external force to the material supporting portion 14 is reduced, the vertical split pieces 26 are elastically restored radially outward and the inner diameter of the material supporting surface 28 is enlarged (that is, the diameter is increased). As described above, in the guide bush 16, the diameter of the material support surface 28 can be adjusted by adjusting the external force applied to the material support portion 14.
[0018]
The guide bush 16 further includes a hollow cylindrical base portion 32 coaxially and integrally extended from the material support portion 14 in the axial direction. A male screw portion 34 is formed along the outer peripheral surface of the base portion 32 at the rear end in the axial direction (right end in FIG. 1) away from the material support portion 14. A single keyway 36 extending in the axial direction at an arbitrary center angular position is formed along the outer peripheral surface of the base 32 between the material support portion 14 and the male screw portion 34.
[0019]
The support 18 includes a hollow cylindrical sleeve member 38 that accommodates and supports the guide bush 16 concentrically, and a column 40 that statically supports the sleeve member 38. The sleeve member 38 is provided with a detent 42 for radially projecting both end portions from the inner and outer peripheral surfaces of the sleeve at an arbitrary center angle position in a central region in the axial direction. The sleeve member 38 can slide the guide bush 16 in the axial direction without rattling in the radial direction while the inner end of the detent 42 is fitted in the key groove 36 of the guide bush 16, and can be rotated relative to each other. Support inability. A frustoconical working surface 44 engageable with the pressure receiving surface 30 of the guide bush 16 is formed in the axial front end region of the inner peripheral surface of the sleeve member 38. The operation surface 44 functions as a pressurizing surface that applies an external force for elastically displacing the material support portion 14 of the guide bush 16 in the radial direction to the pressure receiving surface 30.
[0020]
A column-shaped mounting hole 46 is formed through the column 40, and a single key groove 48 extending in the axial direction is provided at an arbitrary center angle position of the mounting hole 46. The sleeve member 38 is slidable in the axial direction without rattling in the mounting hole 46 of the column 40 with the outer end of the detent 42 fitted in the key groove 48 of the column 40, and Attached so that relative rotation is impossible. On the outer peripheral surface of the sleeve member 38, a flange portion 50 protruding outward is formed near an axial front end (left end in FIG. 1), and a male screw portion 52 is formed in an axial rear end region. A mounting nut 54 having a corresponding female screw is screwed to the male screw portion 52. The sleeve member 38 is attached to the attachment hole 46 with the column 40 held between the flange portion 50 and the attachment nut 54.
[0021]
The operating mechanism 20 includes a hollow cylindrical operating member 56 installed concentrically on the axial rear end side of the sleeve member 38. The actuating member 56 is formed at its axial front end (left end in the figure) with a female screw portion 58 which is screwed into the male screw portion 34 provided at the rear end of the base 32 of the guide bush 16 and at the axial rear end region. Then, a pulley portion 60 extending in a disk shape radially outward is formed. The operating member 56 is operatively connected to the guide bush 16 by screwing the female screw portion 58 into the male screw portion 34 with the axial front end region being concentrically inserted into the axial rear end region of the sleeve member 38. You. In addition, a cover 62 is provided between the operating member 56 and the column 40 to protect a threaded portion between the sleeve member 38 and the mounting nut 54.
[0022]
In the above configuration, when the operating member 56 is rotated in a desired direction while being fixed to the sleeve member 38 in the axial direction, the engagement between the male thread portion 34 and the female thread portion 58 and the engagement between the key groove 36 and the detent 42 are prevented. The guide bush 16 moves in the axial direction inside the sleeve member 38 by the feed screw structure formed by the combination. As a result, the mutual pressure generated between the pressure receiving surface 30 of the guide bush 16 and the working surface 44 of the sleeve member 38 fluctuates, and the inner diameter of the material support 14 changes. In the illustrated embodiment, the internal thread 58 of the guide bush 16 extends until the operating member 56 contacts its axial front end surface 56 a with a shoulder surface 38 a formed along the inner peripheral surface of the sleeve member 38. In this state, the axial movement of the operating member 56 in the axial direction with respect to the sleeve member 38 is prevented.
[0023]
As a characteristic configuration of the present invention, the adjustment mechanism 22 includes a detection unit 64 provided in association with the guide bush 16 and the support 18. The detecting section 64 detects a thrust applied to the guide bush 16 in the axial direction thereof, and allows the radial dimension of the material supporting portion 14 of the guide bush 16 to be appropriately adjusted based on the detected thrust. For that purpose, the adjusting mechanism 22 further includes a driving unit 66 that drives the operating mechanism 20 and a control unit 68 that controls the driving unit 66 based on the thrust detected by the detecting unit 64.
[0024]
In the illustrated embodiment, the detection unit 64 includes a load conversion element (load cell) 70 interposed between the two parts that are relatively movable in the axial direction in relation to the guide bush 16 and the support 18. The load conversion element 70 has an annular elastic body structure, and concentrically surrounds the rear end region in the axial direction of the sleeve member 38, and connects the mounting nut 54 (axially movable portion) and the column 40 (fixed portion). It is inserted and arranged between them. In this state, when pressure is applied to the load conversion element 70 from the mounting nut 54 and the column 40, the load conversion element 70 is elastically deformed, and the mechanical distortion is converted into an electric signal (change in resistance value), and the control unit 68 Output to The load conversion element 70 allows a slight axial movement of the sleeve member 38 with respect to the column 40 within its own elastic deformation range, but the elastic deformation mode is interposed between the mounting nut 54 and the column 40. Thus, the sleeve member 38 can be supported in a substantially stationary state in the axial direction with respect to the column 40.
[0025]
Since the electric signal output from the load converting element 70 corresponds to the thrust detected by the detecting unit 64, the control unit 68 performs an arithmetic process on the electric signal, and if necessary, the driving unit 66 Command operation. The drive unit 66 drives the operating member 56 in a required rotation direction and rotation angle based on a command from the control unit 68, thereby moving the guide bush 16 in the axial direction inside the sleeve member 38, and The inner diameter of the support portion 14 is changed.
[0026]
The procedure for adjusting the radial dimension of the material supporting portion 14 by the adjusting mechanism 22 will be described in further detail with reference to the automatic lathe 12 shown in FIG.
The automatic lathe 12 includes a main shaft 74 mounted on a machine base 72 so as to be movable in the axial direction. The main shaft 74 is rotatably accommodated in a headstock 76, firmly grips the bar W to be processed, and is rotationally driven by a main shaft driving source (not shown). The headstock 76 can be moved in the rotation axis direction of the main shaft 74 by a feed drive source (not shown) along a linear guide device 78 installed on the upper surface of the machine base 72. The column 40 constituting the support 18 of the material guide device 10 is integrally erected on the upper surface of the machine base 72, and the center axis 14 a of the material support portion 14 coincides with the rotation axis of the main shaft 74. Support in the position where it will be. At this position, the guide bush 16 centers and supports the vicinity of the processed portion of the bar W gripped by the main shaft 74, and moves the processed portion of the bar W to the processing operation position by the tool 80 set on the machine base 72. Position.
[0027]
In the illustrated embodiment, a servo motor 66 is installed on the column 40 as a driving unit 66 of the adjustment mechanism 22 of the material guide device 10. A pulley 82 is fixed to an output shaft of the servo motor 66, and a power transmission belt 84 is stretched between the pulley 82 and the pulley portion 60 of the operating member 56. The control unit 68 is configured to be incorporated in a control device (for example, an NC device) that controls the operation of the main shaft 74 of the automatic lathe 12 and the tool post (not shown), but another control device is used. You can also.
[0028]
In the automatic lathe 12 having the above configuration, as a preliminary step before starting a machining program for the bar W, the radial dimension of the material support portion 14 of the guide bush 16 in the material guide device 10 is set to the outer diameter of the bar W. Adjust according to the dimensions. In this pre-adjustment operation, first, the bar W gripped by the main shaft 74 is moved by the axial feed motion of the headstock 76 in a state where no external force is applied to the material support portion 14 in the radial direction. It is inserted into the guide bush 16 from the side and inserted into the material support portion 14. From this state, the servo motor 66 is started to rotate the operating member 56 in a direction in which the female screw portion 58 is screwed into the male screw portion 34 of the guide bush 16. As a result, the guide bush 16 moves axially rearward with respect to the sleeve member 38, and the pressure receiving surface 30 of the guide bush 16 is pressed against the working surface 44 of the sleeve member 38. As a result, the material supporting portion of the guide bush 16 14 is uniformly elastically displaced radially inward, so that the material support surface 28 abuts on the outer peripheral surface of the bar W. During this time, the control unit 68 continuously monitors the torque of the servo motor 66, stops the servo motor 66 when the torque exceeds a predetermined threshold value stored in advance, and moves the material support unit 14 to the temporary bar support position. Hold.
[0029]
Next, with the material support portion 14 of the guide bush 16 held at the temporary bar support position, the main shaft 74 that firmly grips the bar W is moved forward in the axial direction (that is, in a direction approaching the material guide device 10). Feeding exercise. At this time, axial thrust is applied to the guide bush 16 in the axial direction due to the frictional resistance generated between the material support surface 28 of the material support portion 14 and the outer peripheral surface of the bar W. This thrust is caused by the engagement of the male thread portion 34 of the guide bush 16 with the female thread portion 58 of the operating member 56 and the abutment of the axial front end surface 56a of the operating member 56 and the shoulder surface 38a of the sleeve member 38. 38 is transmitted as thrust forward in the axial direction. Further, this thrust is transmitted as a pressure to a load conversion element 70 interposed between the mounting nut 54 screwed to the sleeve member 38 and the column 40. Due to this pressure, the load converting element 70 is elastically deformed, and converts the mechanical strain into an electric signal and outputs it to the control unit 68.
[0030]
The control unit 68 performs an arithmetic process on the electric signal output from the load conversion element 70 to determine whether or not the thrust (or frictional resistance) applied to the guide bush 16 is within a predetermined allowable range stored in advance. to decide. When it is determined that the thrust (or frictional resistance) is within an allowable range, the radial dimension of the material support portion 14 (or the minute gap between the material support portion 14 and the bar W) is determined to be a temporary bar support. The pre-adjustment operation ends assuming that the position has been properly adjusted. On the other hand, when it is determined that the thrust or the frictional resistance applied to the guide bush 16 is not within the allowable range, the servo motor 66 is rotated forward or reverse to readjust the radial dimension of the material support portion 14, and then The thrust applied to the guide bush 16 due to the axial movement of the bar W is detected again and the allowable determination is performed again. Here, for example, if the rotation angle of the output shaft of the servo motor 66 is controlled by a predetermined number of pulses, the axial movement amount of the guide bush 16 with respect to the sleeve member 38 and the radial displacement amount of the material support portion 14 can be changed stepwise. Can be fine-tuned. In this way, a desired minute gap that generates an allowable range of thrust (or frictional resistance) can be secured between the material support portion 14 of the guide bush 16 and the outer peripheral surface of the bar W to be processed.
[0031]
In the material guide device 10 having the above-described configuration, the detection unit 64 including the load conversion element 70 is used to guide the guide bush due to frictional resistance generated between the material support surface 28 of the material support unit 14 and the outer peripheral surface of the bar W. Since the thrust forwardly applied to the shaft 16 in the axial direction is detected between the guide bush 16 and the support 18, the torque between the bar and the material support is monitored by monitoring the torque of the spindle drive servomotor. Unlike the conventional technique of measuring frictional resistance, the thrust can be accurately detected without being affected by torque fluctuations of the spindle drive servomotor due to other factors. As a result, according to the material guide device 10, the radial dimension of the material support portion 14 of the guide bush 16 can be adjusted with high precision in advance.
[0032]
Further, the control unit 68 processes the detection signal of the load conversion element 70 and operates the operating member 56 based on the result of comparing the detected thrust with a predetermined allowable thrust to support the material of the guide bush 16. Since the radial dimension of the portion 14 is adjusted, the distance between the material supporting portion 14 and the bar W derived from the specific parameters such as the outer diameter of the bar W to be processed, the material, and the spindle rotation speed during the processing is adjusted. If the optimum frictional resistance (or thrust) is previously set as an allowable range and stored in the control unit 68, the radial dimension of the material support unit 14 can be increased without depending on the skill and experience of the operator. Can be adjusted to accuracy.
[0033]
In this case, it is preferable that an allowable range of frictional resistance (or thrust) is set in advance in relation to each of various processing steps included in the processing program of the bar W to be processed. For example, in a multifunctional automatic lathe capable of performing a secondary machining process using a rotating tool in a state where the bar W is stationary, in addition to a normal turning process while feeding the bar W in the axial direction. The material guide device 10 can guide and support the bar W without hindering the bar feed operation in a normal turning process, and firmly fixes the bar W against cutting resistance in a secondary working process. It is advantageous to be able to adjust the radial dimension of the material support 14 of the guide bush 16 so as to be able to support it.
[0034]
FIG. 3 shows a modification of the material guide device 10. In the material guide device 10, in addition to the load converting element 70 inserted between the mounting nut 54 and the column 40 at the rear end in the axial direction of the sleeve member 38, A load conversion element 86 is provided between the flange portion 50 (axially movable portion) and the column 40 (fixed portion) at the front end side in the axial direction of 38. The load conversion element 86 has the same annular elastic structure as the load conversion element 70, and is arranged so as to concentrically surround the axial front end region of the sleeve member 38. In this state, when pressure is applied to the load converting element 86 from the flange portion 50 and the column 40, the load converting element 86 is elastically deformed, and the mechanical distortion is converted into an electric signal (resistance change) to convert the mechanical distortion into an electric signal (resistance value change). Output to
[0035]
In the above configuration, with the material support portion 14 of the guide bush 16 held at the temporary bar support position described above, the main shaft 74 that firmly grips the bar W is axially rearward (that is, in a direction away from the material guide device 10). ), The axially rearward thrust applied to the guide bush 16 due to the frictional resistance generated between the material support surface 28 of the material support portion 14 and the outer peripheral surface of the bar W. By the abutment between the pressure receiving surface 30 of the guide bush 16 and the operating surface 44 of the sleeve member 38, the thrust is transmitted to the sleeve member 38 as a thrust backward in the axial direction. This thrust is transmitted as pressure to a load converting element 86 interposed between the flange portion 50 of the sleeve member 38 and the column 40.
[0036]
As described above, according to the above-described modification, the axial thrust, which is the main data for adjusting the radial dimension of the material support portion 14 of the guide bush 16, is applied to the material support portion 14 by the rod W. The detection unit 64 can detect not only when the robot is moved forward in the axial direction, but also when it is moved backward in the axial direction. Therefore, it is possible to optimize the minute gap between the material supporting portion 14 of the guide bush 16 and the outer peripheral surface of the bar W over substantially the entire length of the bar W to be processed.
[0037]
FIG. 4 shows another modification of the material guide device 10. In the material guide device 10, the detection unit 64 of the adjusting mechanism 22 is inserted and arranged between the shoulder surface 38 a (fixed portion) of the sleeve member 38 and the axial front end surface 56 a (axially movable portion) of the operating member 56. The load conversion element 88 is provided. The load conversion element 88 has the same annular elastic structure as the load conversion element 70 described above, and is disposed so as to concentrically surround the rear end region in the axial direction of the guide bush 16. In this state, when pressure is applied to the load converting element 88 from the sleeve member 38 and the operating member 56, the load converting element 88 is elastically deformed, and the mechanical strain is converted into an electric signal (resistance change) to control the load. 68. In addition, the sleeve member 38 is firmly fixed in the axial direction with respect to the column 40 by the mounting nut 54 and installed.
[0038]
In the above configuration, when the main shaft 74 that firmly grips the bar W is moved forward in the axial direction with the material supporting portion 14 of the guide bush 16 held at the temporary bar supporting position described above, An axially forward thrust applied to the guide bush 16 due to frictional resistance generated between the material support surface 28 of the support portion 14 and the outer peripheral surface of the bar W causes the male screw portion 34 and the female screw portion 58 It is transmitted to the operating member 56 as a thrust forward in the axial direction by screwing. This thrust is transmitted as pressure to a load converting element 88 interposed between the sleeve member 38 and the operating member 56. Thus, it can be understood that the same effects as those of the material guide device 10 shown in FIG.
[0039]
The material guide device according to the present invention is not limited to the configuration having the above-described fixed type guide bush, and may have a configuration having a rotary type guide bush that rotates together with a bar that rotates at a high speed during turning. FIG. 5 shows a material guide device 90 according to another embodiment of the present invention provided with such a rotary guide bush. Note that the material guide device 90 has substantially the same configuration as the material guide device 10 described above except for the support structure of the guide bush 16, and corresponding components are denoted by common reference numerals and will be described. Omitted. Further, similarly to the above-described material guide device 10, the material guide device 90 can be installed on the machine base 72 of the automatic lathe 12 shown in FIG.
[0040]
In the material guide device 90, the sleeve member 38 is rotatably housed in a hollow cylindrical support member 94 via a bearing device 92. The support member 94 is attached to the attachment hole 46 of the column 40 using the attachment nut 54 so as to be slidable in the axial direction without rattling in the radial direction and relatively non-rotatable. The support member 94 constitutes the support body 18, and rotates the sleeve member 38 and the guide bush 16 integrally about the rotation axis 16 a (same as the center axis 14 a of the material support portion 14) via a bearing device 92. It is movably supported. A driven gear 96 is attached to the outer peripheral surface of the sleeve member 38 in the axial rear end region. The driven gear 96 is connected to a guide bush drive source (not shown) via a power transmission mechanism (not shown), and has the same rotation speed as the rotation speed of the main shaft 74 (FIG. 2) mounted on the automatic lathe 12 by the guide bush drive source. Is driven to rotate. As a result, when turning is performed by the automatic lathe 12, the driven gear 96, the sleeve member 38, and the guide bush 16 rotate integrally at the same rotation speed as the rotation speed of the main shaft 74 inside the support member 94. I do.
[0041]
In the material guide device 90, the detection unit 64 of the adjustment mechanism 22 is provided between the flange portion 94 a (axially movable portion) at the front end in the axial direction of the support member 94 and the column 40 (fixed portion), and in the axial direction of the support member 94. It comprises a pair of load conversion elements 98 interposed between the mounting nut 54 (axially movable portion) and the column 40 (fixed portion) screwed to the rear end. Each load conversion element 98 has the same annular elastic structure as the load conversion element 70 of FIG. 1, and is disposed so as to concentrically surround the support member 94. In this state, when pressure is applied to each load converting element 98 from the support member 94 or the mounting nut 54 and the column 40, the load converting element 98 is elastically deformed, and the mechanical strain is converted into an electric signal (resistance change). And outputs it to the control unit 68.
[0042]
In the above configuration, when the main shaft 74 that firmly grips the bar W is moved forward or backward in the axial direction while the material support portion 14 of the guide bush 16 is held at the temporary bar support position described above. An axially forward or rearward thrust applied to the guide bush 16 due to frictional resistance generated between the material support surface 28 of the material support portion 14 and the outer peripheral surface of the bar W is transferred from the guide bush 16 to the sleeve. Via the member 38 and the bearing device 92, pressure is transmitted as a pressure to any one of the load converting elements 98 interposed between the support member 94 and the mounting nut 54 and the column 40. According to such a configuration, it will be understood that the same operation and effect as those of the material guide device 10 shown as a modification in FIG.
[0043]
The material guide device according to the present invention is also applicable to a configuration in which the operation mechanism is manually operated to adjust the material support portion of the guide bush. FIG. 6 shows a material guide device 100 according to still another embodiment of the present invention provided with such a manually operated adjustment mechanism. The material guide device 100 has substantially the same configuration as the material guide device 10 described above, except for the configuration of the adjustment mechanism. Corresponding components have the same reference characters allotted, and description thereof will not be repeated. . Further, similarly to the above-described material guide device 10, the material guide device 100 can be installed on the machine base 72 of the automatic lathe 12 shown in FIG.
[0044]
The material guide device 100 includes an operating member 56 having a pulley portion 60 shown in FIG. 56 are provided. As an adjusting mechanism 22 for adjusting the radial dimension of the material support portion 14 of the guide bush 16 via the operating mechanism 20, a detecting portion 64 provided in association with the guide bush 16 and the support 18; And a control unit 68 for notifying a worker of the detection result of the detection. The detecting unit 64 detects the thrust applied to the guide bush 16 in the axial direction, and the operator knows the detected thrust via the control unit 68, so that the material supporting unit of the guide bush 16 can be manually operated. 14 so that the radial dimension can be properly adjusted.
[0045]
In the illustrated embodiment, the detection unit 64 is constituted by a piezoelectric element 104 interposed between two parts that are relatively movable in the axial direction in relation to the guide bush 16 and the support 18. The piezoelectric element 104 has a hollow cylindrical structure, concentrically surrounds the mounting hole 46 of the column 40, and includes an end plate portion 102 (axially movable portion) and a column 40 (fixed portion) of the operating member 56. Is fixedly arranged between them. In this state, when pressure is applied to the piezoelectric element 104 from the end plate portion 102 of the operating member 56 and the column 40, the piezoelectric element 104 converts the mechanical strain into an electric signal (voltage) and outputs the signal to the control unit 68. . The control unit 68 performs an arithmetic process on the electric signal, and displays a detection result by the piezoelectric element 104 on, for example, a display device (not shown).
[0046]
In the above configuration, when the main shaft 74 that firmly grips the bar W is moved forward or backward in the axial direction while the material support portion 14 of the guide bush 16 is held at the temporary bar support position described above. The axially forward or rearward thrust applied to the guide bush 16 due to frictional resistance generated between the material support surface 28 of the material support portion 14 and the outer peripheral surface of the bar W is actuated from the guide bush 16. The pressure is transmitted to the member 56 and further transmitted to the piezoelectric element 104 interposed between the operating member 56 and the column 40 as a pressure or a tensile force (that is, a radial pressure) in the axial direction.
[0047]
The operator refers to the detection result by the piezoelectric element 104 notified by the control unit 68 and determines whether or not the thrust (or frictional resistance) applied to the guide bush 16 is within a predetermined allowable range set in advance. Judge. When it is determined that the thrust (or frictional resistance) is within an allowable range, the radial dimension of the material support portion 14 (or the minute gap between the material support portion 14 and the bar W) is determined to be a temporary bar support. The pre-adjustment operation ends assuming that the position has been properly adjusted. On the other hand, when it is determined that the thrust or the frictional resistance applied to the guide bush 16 is not within the allowable range, the operating member 56 is manually rotated forward or backward to readjust the radial dimension of the material support portion 14. Then, the detection of the thrust applied to the guide bush 16 by the axial movement of the bar W and the permissible determination are performed again. Note that the preset thrust allowance may be recorded in a document or the like that can be viewed at any time. It will be understood that such a configuration provides the same operation and effect as the material guide device 10 shown as a modification in FIG.
[0048]
While some preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made. For example, the detection unit of the adjustment mechanism may be configured by a dimension measuring device that is installed on the support and measures the axial dimension of the guide bush.
[0049]
【The invention's effect】
As is apparent from the above description, according to the present invention, in the material guide device installed on the automatic lathe, the radial dimension of the material support portion of the guide bush can be increased without depending on the skill and experience of the operator. It will be possible to pre-adjust to accuracy. Therefore, an automatic lathe equipped with this material guide device is a high-performance machine tool capable of performing high-precision turning.
[Brief description of the drawings]
FIG. 1 is a sectional view partially showing a configuration of a material guide device according to an embodiment of the present invention in a block diagram.
FIG. 2 is a partially cutaway front view showing a main part of an automatic lathe according to an embodiment of the present invention equipped with the material guide device of FIG. 1;
FIG. 3 is a sectional view showing a modification of the material guide device of FIG. 1;
FIG. 4 is a sectional view showing another modification of the material guide device of FIG. 1;
FIG. 5 is a sectional view partially showing a configuration of a material guide device according to another embodiment of the present invention in a block diagram.
FIG. 6 is a sectional view partially showing a configuration of a material guide device according to still another embodiment of the present invention in a block diagram.
[Explanation of symbols]
10, 90, 100 ... material guide device
12 ... Automatic lathe
14 Material support
16… Guide bush
18 ... Support
20 ... Operation mechanism
22 ... Adjustment mechanism
38 ... Sleeve member
40 ... column
54 ... Mounting nut
56 ... Working member
64 Detector
66 ... Drive unit
68 ... Control unit
70, 86, 88, 98 ... load conversion element
72 ... Machine stand
74 ... spindle
104 ... Piezoelectric element

Claims

A guide bush having a hollow cylindrical material support portion elastically displaceable in a radial direction, a support for supporting the guide bush, an operation mechanism for elastically displacing the material support portion of the guide bush in a radial direction, A material guide device comprising: an adjustment mechanism for adjusting a radial dimension of the material support portion via an operation mechanism;
The adjustment mechanism includes:
A detection unit provided in association with the guide bush and the support, and configured to detect a thrust applied to the guide bush in an axial direction thereof,
Based on the thrust detected by the detection unit, to be able to adjust the radial dimension of the material support unit,
Material guide device characterized by the above-mentioned.

The material guide device according to claim 1, wherein the adjustment mechanism further includes a drive unit that drives the operation mechanism, and a control unit that controls the drive unit based on the thrust detected by the detection unit.

The said control part controls the said drive part based on the comparison of the thrust permissible value preset with respect to each of various processing processes which process a to-be-processed raw material, and the said thrust detected by the said detection part. 3. The material guide device according to 2.

The material according to any one of claims 1 to 3, wherein the detection unit includes a load conversion element interposed between two portions that are relatively movable in an axial direction in relation to the guide bush and the support. Guide device.

The material guide according to any one of claims 1 to 3, wherein the detection unit includes a piezoelectric element interposed between two portions relatively movable in an axial direction in relation to the guide bush and the support. apparatus.

An automatic lathe having the material guide device according to any one of claims 1 to 5 installed near a processing operation position of a material to be processed.