JP2004114179A

JP2004114179A - Method and device for super precise centerless grinding

Info

Publication number: JP2004114179A
Application number: JP2002277785A
Authority: JP
Inventors: Mohee Sakae; 寒河江　茂兵衛; Shigemi Shikama; 志鎌　重美; Masayuki Takahashi; 高橋　征幸
Original assignee: Micron Machinery Co Ltd
Current assignee: Micron Machinery Co Ltd
Priority date: 2002-09-24
Filing date: 2002-09-24
Publication date: 2004-04-15

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform centerless grinding finishing for a plurality of tapered surfaces having different tapered angles with super high precision of less than 0.1 microns at a low cost. <P>SOLUTION: A preliminary finishing part P and a super high precision finishing part F constituted of two pairs of centerless grinding mechanisms having the same shape and dimension are installed in parallel on a common bed B. A workpiece (not illustrated because the workpiece is very small in a scale of this figure) is preliminarily finished with high precision (micron order) by the preliminary finishing part P. The centerless grinding finishing is performed for a tapered part with super high precision by the super high precision finishing part F. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、テーパ角を異にする複数のテーパ面を有する円柱状のワークを、許容誤差０．１ミクロン未満の超高精度にセンタレス研削する技術に関するものである。ただし、超高精度に研削仕上げするのは、指定された複数のテーパ面だけである。なお、前記テーパ角は、０度から１８０度までの間で任意の値をとることができる。
【０００２】
【従来の技術】
図５は、センタレス研削機の基本的構造を示す模式図である。
調整砥石１は砥石車であるが、作用的には、ワークを磨り減らすというよりは摩擦車として機能する部材であって、
該調整砥石１とブレード４とによって円柱状のワーク３を支承して円弧矢印ａ方向に回転する。
この調整砥石１の矢印ａ方向回転により、摩擦伝動を受けて、ワーク３は円弧矢印ｂ方向に回転せしめられる。
研削砥石４は砥石車であって、前記ワークの矢印ｂ方向回転よりも高い周速で円弧矢印ｃ方向に回転しつつ、該ワーク３に接触して、これを研削する。
研削砥石４がワーク３に与える研削力は、該ワーク３の矢印ｂ方向の回転を加速する方向に作用するが、調整砥石１との摩擦力が制動力として働くので、ワーク３の周速は調整砥石１の周速とほぼ等しくなる。
特殊なセンタレス研削方式としては、例えば接線送りと呼ばれるように、ブレード４を設けないものも有るが、「調整砥石・ブレード・研削砥石」の３部材はセンタレス研削研削機の基本を形成するものである。
本発明においては説明の便宜上、これら３構成部材の１組をセンタレス研削機構と呼ぶ。
なお、センタレス研削装置とは、センタレス研削機構に加えて、クーラント（切削油）循環機構や搬送機構や駆動機構などの内の少なくとも一つの機構と組み合わされて、設置の単位となる複合体をいうものとする。ただし、このセンタレス研削装置の定義は、本発明の技術的範囲を限定するものではない。
【０００３】
【発明が解決しようとする課題】
センタレス研削技術によると、円柱状のワークを高精度で研削することができ、特に、センタレス研削特有の造円作用によって真円度が高いという特長が有る。
また、応用技術として、テーパ面などの回転面をセンタレス研削することも公知であり、広く実用されている。
しかし、特に複雑なテーパ面を有するワークを、許容誤差０．０１ミクロン未満の超高精度でセンタレス研削し得る技術は未だ開発されていなかった。
図６は、複雑なテーパ面を有するワークの１例を示す正面図である。
超高精度のテーパ面を有するワーク５は、４箇所の超高精度（＜０．１μｍ）仕上面を有している。
すなわち、テーパ角θのテーパ面５ａと、
テーパ角φ＞θのテーパ面５ｂと、
テーパ角がマイナス（−ψ）、つまり先開き形テーパ面５ｃと、
テーパ角がゼロのテーパ面、つまり円柱面５ｄとの４箇所が超高精度仕上面である。
【０００４】
５ｊは端面で、超高精度までは求められず、ミクロンオーダーの高精度仕上面であり、５ｅはネジ部である。
また、本例の超高精度ワーク５には油孔５ｉが穿たれているが、この油孔は超高精度仕上面との間に直接的な関係は無い。
前記４箇所の超高精度テーパ面（５ａ，５ｂ，５ｃ，５ｄ）相互の間には、いわゆる“逃げ”が形成される。テーパ面とテーパ面とに挟まれた逃げ部は、必然的に輸状をなす。
符号５ｆを付して示した部分を第１研削逃げ部（詳しくは研削逃げ輪状部）と名付ける。同様に５ｇは第２研削逃げ輪状部、５ｈは第３研削逃げ輪状部と名付ける。これらの輪状の逃げ部は、この超高精度ワーク５の機能上からは格別の制度を求められていない。
【０００５】
図６に例示したように、テーパ角を異にする複数箇所のテーパ面を、超高精度でセンタレス研削しようとする場合、
実験室的に行なうことは従来技術によっても可能であり、超高精度に仕上げるべき円柱面（テーパ角ゼロの部分）を調整砥石とブレードとで支持しながら（図５参照）、研削砥石によってテーパ面を１箇所ずつ超高精度で研削仕上げすれば良い。
しかし、工業的に大量生産する場合、上述のように複数箇所のテーパ面を１つずつ研削仕上げすると、次のような不具合が有る。
【０００６】
複数箇所のテーパ面が互いにテーパ角を異にしているので、１箇所を研削するごとにセンタレス研削装置の調整状態を修正し直さなければならない。このため、高度の熟練と多大の労力とを要する。
複数組の、調整状態の異なるセンタレス研削装置を並べて設置し、１個のワークを複数のセンタレス研削装置に、順次に通過させることも考えられるが、０．１ミクロンの超高精度を求める場合、複数の研削装置を通過させては所望の超高精度は得られない。
（注）テーパ面の一つ一つが正しい形状，寸法であっても、テーパ面相互の位値精度が出ない。
【０００７】
また、１箇所ずつ超高精度研削仕上げを繰り返している途中で、何れか１箇所のテーパ面を削り過ぎてしまうと、当該ワークが廃品になってしまい、材料費はもとより、それまでの加工工程が全部無駄になってしまう。
いま仮に、１箇所の超高精度テーパ面研削の検査合格率（歩留り）が９０％であるとした場合、このような超高精度テーパ面研削を４回繰り返すと、総合した検査合格率は０．９の４乗≒２／３に落ちてしまう。
検査合格率（歩留り）が２／３になるということのみに着目しても、生産コストを３３％上昇させることを意味し、工業生産において見逃し得ない問題である。
【０００８】
本発明は上述の技術的問題に鑑みて為されたものであって、
例えば図６に示したように、複数の、テーパ角を異にする超高精度テーパ面を有する円柱状部材を、高能率、高歩留り、低コストで研削仕上げする技術を提供しようとするものである。
【０００９】
【課題を解決するための手段】
本発明者は、前記の目的を達成するため、基礎技術の試験研究を鋭意くり返した結果、次のような知見を得た。
ａ．複数の超高精度テーパ面（５ａ，５ｂ，５ｃ，５ｄ）を０．１μｍ以内の超高精度で研削仕上げするためには、これに先立って、これら超高精度テーパ面の間に位置する輪状の逃げ部（５ｆ，５ｇ，５ｈ）を、ミクロンオーダーで予備仕上げしておかなければならない（所望の超高精度を出すため）
ｂ．予備仕上げされたワークの超高精度テーパ面（５ａ，５ｂ，５ｃ，５ｄ）を、最終工程で、全箇所同時に研削仕上げすることが望ましい（精度上、および能率上）
ｃ．予備仕上げされたワークの環境条件を、できる限り変えないで最終仕上げ工程（超高精度）に移行すること。
こうした研究結果を見て、当たり前のことのような錯覚を起こし易いが、それはコロンブスの卵の諺のごとくであって、「複数の超高精度テーパ面を工業的な採算性を以て研削仕上げする」という目的意識を以て、実際に試験研究を繰り返さなければ到達し得る知見ではない。
【００１０】
前記の知見に基づいて創作した請求項１に係る発明方法の構成は、円柱状ワークの複数箇所に設けられた、互いにテーパ角を異にするテーパ面を、超高精度でセンタレス研削する方法において、
ほぼ等しい構造，寸法の２組のセンタレス研削機構を、共通のベッドの上に並べて設置し、
上記２組の内の片方のセンタレス研削機構によって、「前記複数箇所の超高精度テーパ面の間に挟まれた輪状の区域」を高精度で予備仕上げし、
予備仕上げされたワークを、２組の内に他方のセンタレス研削機構に移し、
該他方のセンタレス研削機構によって、「一体的に結合された、複数のテーパ面を有する研削砥石」を用いて、複数箇所の超高精度テーパ面を同時に超高精度で研削仕上げすることを特徴とする。
【００１１】
以上に説明した請求項１の発明方法によると、
イ．超高精度でテーパ面に仕上げられるべき複数の部分の中間に位置する輪状の逃げ部が、予め高精度で予備仕上げされているので、該複数の部分を超高精度で仕上げることが工業生産的に可能になる。
ロ．予備仕上と超高精度仕上とを「並べられた２組のセンタレス研削機構」によって行なうので、予備仕上の環境条件と超高精度仕上との環境条件が均一となり、環境条件の変化に因る誤差が混入しない。
ハ．複数のテーパ面を、一体的に結合された研削砥石によって１工程で仕上げるので、各テーパ面相互の間に位置誤差を生じる虞れが無い。
以上イ．ロ．ハ各項の総合効果により、複数のテーパ面を工業生産的に、高能率，低コストで、許容誤差０．１μｍ未満の超高精度でセンタレス研削仕上げすることができる。
【００１２】
請求項２に係る発明方法の構成は、前記請求項１の発明の構成要件に加えて、前記２組のセンタレス機構を相互に平行に設置し、
かつ、双方の研削砥石軸相互をほぼ同一水平面上に位置せしめるとともに、
双方の調整砥石軸相互をほぼ同一水平面上に位置せしめることを特徴とする。
以上に説明した請求項２の発明方法によると、予備仕上研削の作業条件と超高精度仕上研削の作業条件とを、より厳密に一致させることができ、かつ、より高能率で施工することができる。その結果、最終製品検査の合格率（歩留り）が向上して総合コストが有効に低減される。
【００１３】
請求項３に係る発明方法の構成は、前記請求項１または請求項２の発明方法の構成要件に加えて、前記２組のセンタレス研削機構の内の片方で予備仕上げされたワークを、その直径方向に把持して上方に持ち上げ、
上記ワークを、その軸心方向に、ほぼ水平に移動させて、下方に持ち下げ、
前記２組のセンタレス研削機構の内の他方に供給することを特徴とする。
以上に説明した請求項３の発明方法によると、予備仕上げ工程を最終研削仕上げ工程との間に、一時的貯留や中間検査などの工程を置くことなく、最短距離で搬送するので、超高精度の実現がより容易となり、歩留りが一層良くなる。
【００１４】
請求項４に係る発明方法の構成は、前記請求項１ないし請求項３の発明方法の構成要件に加えて、ワークに形成される多数のテーパ面の中に、テーパ角９０度のテーパ面すなわち直角な端面が有る場合、
上記の端面と反対側の端面に、軸心方向の推力を与えつつ、前記直角な端面を研削砥石によってセンタレス研削することを特徴とする。
以上に説明した請求項４の発明方法によると、複数の超高精度テーパ面を有する円柱状ワークの何れか片方の端に、高精度または超高精度で研削仕上げすべき端面が有る場合、該ワークを予備仕上工程と超高精度研削仕上工程との２工程でセンタレス研削する間に、該端面を所望の精度で研削仕上げすることができ、従来技術に比して工数を節減することができる。
【００１５】
請求項５に係る発明方法の構成は、前記請求項１ないし請求項４の発明方法の構成要件に加えて、ワークに、テーパ角０度のテーパ面すなわち円柱面が有る場合、
円柱面状にドレッシングした調整砥石の外周面を、ワークの円柱面のみに接触させ、ワークの「テーパ角０度でない箇所」には調整砥石を接触させないことを特徴とする。
以上に説明した請求項５の発明方法によると、複数のテーパ面の内の一つがテーパ角ゼロである場合（すなわち円柱面である場合）この円柱面をブレードと調整砥石車とで安定に支持して、より確実に超高精度の研削仕上げを行なうことができる。
【００１６】
請求項６に係る発明方法の構成は、前記請求項１ないし請求項５の発明方法の構成要件に加えて、同一形状，寸法の多数のワークを連続的に研削する場合、
２組のセンタレス研削機構の内の片方によって、後続のワークを高精度で予備仕上げしながら、
上記と併行して、２組のセンタレス研削機構の他方によって、先行のワークを超高精度で研削仕上げし、
先行ワークの研削仕上げを終えると、該先行ワークを他方のセンタレス機構から搬出し、
ワークの無くなった他方のセンタレス研削機構の回転を継続しつつ、「予備仕上げを終えた後続のワーク」を該他方のセンタレス研削機構へ移送するとともに、
前記片方のセンタレス研削機構に「前記後続のワークの次に続くワーク」を搬入し、
以上の操作を繰り返しつつ、多数のワークを順次に、かつ連続的にセンタレス研削することを特徴とする。
以上に説明した請求項６の発明方法によると、同一仕様の多数のワークを、高能率で超高精度研削することができる。
本請求項６を適用して多数のワークを連続的に流れ作業で研削すると、２組のセンタレス機構が交互に休止することなく、それぞれが連続的に運転されて機械装置の稼働率が１００％に近い高率に維持される。
従って、作業能率あたりの設備コストが低減される。
【００１７】
請求項７に係る発明装置の構成は、独立に回転速度を制御される研削砥石車と、独立に回転速度を制御される調整砥石車と、ブレードとから成るセンタレス研削機構の２組が、共通のベッドの上に設置されており、
かつ、上記２組のセンタレス研削機構のそれぞれに設けられている研削砥石車のそれぞれに研削砥石ドレッサが設けられるとともに、
上記２組のセンタレス研削機構のそれぞれに設けられている調整砥石車のそれぞれに共通な調整砥石ドレッサが設けられていることを特徴とする。
以上に説明した請求項７の発明装置を適用すると、独立して制御される２組のセンタレス研削機構が共通のベッド上に設置されているので、前記請求項１に係る発明方法を容易に実施して、その効果を充分に発揮させることができる。
特に、上記２組のセンタレス研削機構のそれぞれが研削砥石ドレッサを備えているので、各センタレス研削機構の工程に応じた研削砥石をドレッシングすることができ、しかも、各センタレス研削機構に共通の調整砥石ドレッサが設けられているので、該２組のセンタレス研削機構相互に調整砥石を厳密に正確に同心，同寸にドレッシングすることができ、０．１μｍ未満の超高精度センタレス研削仕上げを可能ならしめる。
【００１８】
請求項８に係る発明装置の構成は、前記請求項７の発明装置の構成要件に加えて、前記２組のセンタレス研削機構は、相互に平行に共通のベッド上に設置されており、
上記２組のセンタレス研削機構それぞれの研削砥石軸が、ほぼ水平な共通の平面に沿って送り操作できる構造であるとともに、
該２組のセンタレス研削機構それぞれの調整砥石軸が、ほぼ水平な１直線に沿って同心状を為すように調整し得る構造であることを特徴とする。
以上に説明した請求項８の発明装置によると、２組のセンタレス研削機構が共通のベッドの上に平行に設置され、かつ、該２組のセンタレス研削機構はそれぞれの研削砥石軸および調整砥石軸を同心状に構成され、少なくとも同心状に調整できるようになっているから、予備仕上げの環境条件と超高精度研削仕上げの環境条件とを一致させることが容易である。
【００１９】
請求項９に係る発明装置の構成は、前記請求項７ないし請求項８の発明装置の構成要件に加えて、前記２組のセンタレス研削装置の片方によって予備仕上げされたワークを、その直径方向に把持し、
把持したワークを持ち上げて軸心方向に移動させ、
他方のセンタレス研削機構に供給する搬送機構が設けられていることを特徴とする。
以上に説明した請求項９の発明装置によると、予備仕上げされたワークを、最短距離で、最短時間で、超高精度研削仕上げ用のセンタレス研削機構に供給することができ、搬送中にワークの状態が変化することを最小限まで抑制できるので、仕上げ研削の精度向上に有効である。
【００２０】
請求項１０に係る発明装置の構成は、前記請求項７ないし請求項９の発明装置の構成要件に加えて、前記２組のセンタレス研削機構の内、少なくとも１組のセンタレス研削機構は、ワークに対して軸心方向の推力を与える手段を備えていることを特徴とする。
以上に説明した請求項１０の発明装置によると、ワークの一端に、高精度研削仕上げ、または超高精度研削仕上げすべき端面が有る場合、
端面研削専用の一つの工程を設けなくても、予備仕上げ工程において、または超高精度研削仕上げ工程において、前記の端面を所望の精度で研削仕上げすることができる。
このため、ワーク全体として加工工程が少なく、能率良く低コストでセンタレス研削を行なうことができる。
【００２１】
請求項１１に係る発明装置の構成は、前記請求項７ないし請求項１０の発明装置の構成要件に加えて、前記２組のセンタレス研削機構は、一つのクーラント循環系統を共有しており、
上記クーラント循環系統は、共用のクーラントタンクと、共用のポンプと、共用のフィルタとを備えており、
かつ、前記共用のポンプから吐出されたクーラントをそれぞれのセンタレス研削機構に分配する分岐管路が設けられていることを特徴とする。
以上に説明した請求項１１の発明装置によると、２組のセンタレス研削機構がクーラント循環系統を共有しているので構成が簡単で、小形軽量，低コストであるのみでなく、予備仕上げ中のワークと超高精度研削仕上げの中のワークとが同一循環系のクーラントによって冷却されるので、両者の温度条件や潤滑条件が厳密に同様に保たれ、製品の仕上げ精度維持に有効である上に、研削機械装置のメンティナンスが容易である。
【００２２】
【発明の実施の形態】
図１は、本発明に係る超高精度センタレス研削装置の１実施形態を示す平面図であり、図２は同じく正面図である。この実施形態は、前掲の図６に示したようにテーパ角を異にする複数のテーパ面を超高精度でセンタレス研削仕上げするように構成したものである。
（図１参照）共用のベッドＢの上に、同形同寸の２組のセンタレス機構から成る予備仕上部Ｐと、同じく超高精度仕上部Ｆとが搭載されている。
１ｐは、予備仕上部Ｐの調整砥石、１ｆは超高精度仕上部Ｆの調整砥石である。同様に、４ｐは予備仕上研削砥石、４ｆは超高精度研削砥石である。
Ｓｒは、予備仕上調整砥石１ｐと超高精度調整砥石１ｆとの共通の軸心である。この共通の調整砥石軸Ｓｐは、共通のベッドＢに対して移動しない。ただし、後に図２を参照して詳しく述べるようにスライドを介してベッドＢに搭載されている。
図示の状態において、２個の研削砥石４ｐ，４ｆは共通の軸心Ｓｇと同心となるように調整されている。ただし、これらの研削砥石４ｐおよび研削砥石４ｆはそれぞれ図の左右方向にスライド（切込み送り）されるので、必ずしも常に同心を保っている訳ではないが、同心状態となるように調整し得る構造である（同心に調整できるとは、それぞれの砥石軸が共通の平面上に位置しており、かつ、双方の砥石軸が相互に平行を保って移動（切込み送り）される構造であることを意味している。
上記双方の研削砥石４ｐ，４ｆは、それぞれ独立に制御される研削砥石駆動モータ６ｐ，６ｆを備えている。
【００２３】
前記双方の調整砥石１ｐ，１ｆは、それぞれ独立に制御し得る駆動モータ１ｐｍ，１ｆｍを有している。
ただし、先に述べたように２つの調整砥石１ｐ，１ｆは常に同心であるから、これら調整砥石を１個の共用駆動モータで回転駆動することもでき、このような変形例も本発明の技術的範囲に属する。
前記２個の研削砥石４ｐ，４ｆは、それぞれ専用の研削砥石ドレッサ７ｐ，７ｆを備えている。
一方、２個の調整砥石１ｐ，１ｆは、共通の調整砥石ドレッサ８を備えている。このように調整砥石ドレッサを共用することは、前記双方の調整砥石１ｐ，１ｆを同心に設置することと相俟って、本願発明に特有の構成であり、本願発明特有の効果（詳細後述）を奏する。
【００２４】
正面図を描かれた図２においては、２組のセンタレス研削機構（図１で説明した超高精度仕上部Ｆと予備仕部上Ｐとのそれぞれを構成している）は、重なって１組に見えている。
符号１を付して示したのは調整砥石であって、詳しくは予備仕上調整砥石１ｐと超高精度調整砥石１ｆとの重なりである。
同様に符号４は研削砥石、符号７は研削砥石ドレッサである。
符号６は研削砥石駆動モータであって、図面を簡素化して読図を容易ならしめるように、その支持部材は図示を省略してある。
原理的には、前記調整砥石１の軸心ＳｒはベッドＢに対して固定されるが、実際の実施形態においてはブレード２と共に調整砥石送りスライド１ｓに搭載されている。
本図２では重なっているが、２組のセンタレス研削機構それぞれの研削砥石４は、それぞれ研削砥石送りスライド４ｓに搭載されている。
【００２５】
図１と図２とを参照して理解されるように、図示した調整状態では２個の研削砥石４ｐ，４ｆの軸心Ｓｇが同一水平線上に揃っている。
しかし、２個の研削砥石４ｐ，４ｆはそれぞれ独立して図の左右方向に切込み送りされる（研削砥石送りスライド４ｓによる）。
以上のごとくであるから、本実施形態の超高精度センタレス研削装置を見たとき、２個の調整砥石の軸心は一致しているが、２個の研削砥石の軸心は一般に一致していない。ただし、何れかの研削砥石を切込み送り方向（図の左右方向）に移動させて一致させることができるようになっている。
なお、２個の調整砥石１ｐ，１ｆの軸心は常に一致しており、少なくとも運転中の状態では正確に一致している。
【００２６】
次に、前掲の図１，図２に示した実施形態の装置を用いて、前掲の図６に示した「テーパ角を異にする複数のテーパ面」を有するワークを超高精度（０．１μｍ未満）に研削仕上げした１例について述べる。
図３（Ａ）は予備仕上作業を表した模式図、（Ｂ）は超高精度研削仕上作業を表した模式図である。
しかし、本例は、予備仕上作業と言ってもミクロンオーダーの精密研削であるから、予備仕上前のワークと、予備仕上後のワークと、超高精度研削仕上げされた製品とを手にとって眺めてみても、ほとんど見分けはつかない。
本例のワークは４箇所の超高精度テーパ面を有しており（図６参照）、
符号５ａを付したテーパ面はテーパ角θ
符号５ｂを付したテーパ面のテーパ角は、φ（ただしφ＞θ）
符号５ｃを付したテーパ面のテーパ角はマイナスψ、
符号５ｄを付したテーパ面のテーパ角はゼロ（すなわち円柱面）である。
以上４箇所のテーパ面を超高精度でセンタレス研削するため、予め、これら超高精度仕上部の間に挟まれている輪状の逃げ部５ｆ，５ｇ，および５ｈを、高精度（ミクロンオーダー）で研削仕上げ（予備仕上げ）する。
なお、本例においてはテーパ角９０度のテーパ面（すなわち直角端面）５ｊを高精度（ミクロンオーダー）研削仕上げする。本発明を実施する際、直角端面は有っても無くても実施することができる。
【００２７】
図３（Ａ）参照、符号４ｐを付して示したのは、予備仕上作業を行なうためにドレッシングした研削砥石である。
この予備仕上工程においては、第１研削逃げ輪状部５ｆと、第２研削逃げ輪状部５ｇと、第３逃げ輪状部５ｈとを同時に高精度（ミクロンオーダー）で研削仕上げする。
設計仕様書においてミクロンオーダーの高精度を要求されているか要求されていないかに拘らず、本発明方法においては、次の工程でテーパー部を超高精度仕上げするため、これらの輪状の逃げ部を高精度で研削しておくのである。
なお、本例においては、この予備仕上げ工程において端面５ｊを高精度で研削仕上げする。これは設計仕様書の要求によるものである。
予備仕上研削砥石４ｐには、
第１逃げ輪状部５ｆを研削するための第１逃げ研削部４ｂと、
第２逃げ輪状部５ｇを研削するための第２逃げ研削部４ｃと、
第３逃げ輪状部５ｈを研削するための第３逃げ研削部４ｄと、
端面５ｊを研削するための端面研削部４ａとが形成されている。
このように、予備仕上作業専用の研削砥石４ｐを構成するため（図１参照）、予備仕上部Ｐに専属する研削砥石ドレッサ７ｐが設けられていることは非常に好都合である。
図３（Ａ）に示した予備仕上研削砥石４ｐは、図１に示されているように、予備仕上部Ｐのセンタレス研削機構を構成している。この予備仕上部Ｐにワーク（図１において図示省略・微小のため）を供給して、図３（Ａ）のようにして予備仕上げを行なう。図１においてワーク（図示省略）の軸心は、調整砥石の中心線Ｓｒと平行であり、調整砥石１ｐと研削砥石４ｐとの間に位置している。
【００２８】
（図１参照）予備仕上部Ｐにおいてワークの予備仕上げが終わると、図示を省略した搬送手段によって該ワークを直径方向に把持し、上方（紙面手前側）へ持ち上げ、該ワークの軸心方向（砥石中心線Ｓｒと平行）に移動させ、持ち下げて（紙面の奥行方向）超高精度仕上部Ｆのセンタレス研削機構に供給する。
これにより、ワークは予備仕上部Ｐから超高精度仕上部Ｆに、最短距離，最短時間で移送される。
このように効率的な搬送をすることは、作業能率の向上にも有効であり、ワークの環境条件を変えないで次工程に受け渡すという意味で重要である。
ワークを送り出した予備仕上部Ｐには、後続のワークが供給され、超高精度仕上部Ｆで研削仕上げされたワークは製品検査工程に送られる。
このようにして、多数のワークが順次に流れ作業でセンタレス研削される。
【００２９】
図３（Ａ）に示したようにテーパ角９０度のテーパ面（端面５ｊ）が有る場合、矢印ｓ方向のスラスト力（推力）を与える。これにより、独立した端面研削工程を設ける必要無く、該端面を高精度または超高精度で仕上げることができる。
推力を与える手段はセンタレス研削について公知の手段を適用すれば良い。
図３に示した例のようにテーパ角ゼロのテーパ面（円柱面）が有る場合、ブレードと調整砥石とによるワークの支持および回転速度の制御は、該円柱面のみによって行ない、調整砥石を他のテーパ面に触れさせないようにする。これにより、ワークと調整砥石との間の滑りが最少限まで抑制される。
【００３０】
センタレス研削機は一般にクーラント（研削油）循環供給系統が設けられている。図４は、本実施形態におけるクーラント循環供給系統の概要的な配管系統図である。
クラントポンプ９は駆動モータ１０によって回転駆動され、クーラントタンク１１内のクーラントと、ストレーナ１２を介して吸入圧送し、フィルター１４を経て送給する。１３は調圧弁である。
フィルター１４の下流側に分岐管１５が設けられていて、予備仕上部Ｐと超高精度仕上部Ｆとに対して並列にクーラントを供給する。
このようにして、クーラント循環系統の要部を共用することによって、研削装置全体の構造が簡単で小形，軽量，低コストとなる上に、予備仕上部Ｐと超高精度仕上部Ｆとの冷却・潤滑条件が正確に等しくなる。このようにして両部Ｐ，Ｆの環境条件を同一ならしめることは、０．１μｍ未満の超高精度を得るために有効である。
【００３１】
【発明の効果】
以上に本発明の実施形態を挙げてその構成，作用を明らかならしめたように、請求項１の発明方法によると、
イ．超高精度でテーパ面に仕上げられるべき複数の部分の中間に位置する輪状の逃げ部が、予め高精度で予備仕上げされているので、該複数の部分を超高精度で仕上げることが工業生産的に可能になる。
ロ．予備仕上と超高精度仕上とを「並べられた２組のセンタレス研削機構」によって行なうので、予備仕上の環境条件と超高精度仕上との環境条件が均一となり、環境条件の変化に因る誤差が混入しない。
ハ．複数のテーパ面を、一体的に結合された研削砥石によって１工程で仕上げるので、各テーパ面相互の間に位置誤差を生じる虞れが無い。
以上イ．ロ．ハ各項の総合効果により、複数のテーパ面を工業生産的に、高能率，低コストで、許容誤差０．１μｍ未満の超高精度でセンタレス研削仕上げすることができる。
【００３２】
請求項２の発明方法によると、予備仕上研削の作業条件と超高精度仕上研削の作業条件とを、より厳密に一致させることができ、かつ、より高能率で施工することができる。その結果、最終製品検査の合格率（歩留り）が向上して総合コストが有効に低減される。
請求項３の発明方法によると、予備仕上げ工程を最終研削仕上げ工程との間に、一時的貯留や中間検査などの工程を置くことなく、最短距離で搬送するので、超高精度の実現がより容易となり、歩留まりが一層良くなる。
請求項４の発明方法によると、複数の超高精度テーパ面を有する円柱状ワークの何れか片方の端に、高精度または超高精度で研削仕上げすべき端面が有る場合、該ワークを予備仕上工程と超高精度研削仕上工程との２工程でセンタレス研削する間に、該端面を所望の精度で研削仕上げすることができ、従来技術に比して工数を節減することができる。
請求項５の発明方法によると、複数のテーパ面の内の一つがテーパ角ゼロである場合（すなわち円柱面である場合）この円柱面をブレードと調整砥石車とで安定に支承して、より確実に超高精度の研削仕上げを行なうことができる。
請求項６の発明方法によると、同一仕様の多数のワークを、高能率で超高精度研削することができる。
本請求項６を適用して多数のワークを連続的に流れ作業で研削すると、２組のセンタレス機構が交互に休止することなく、それぞれが連続的に運転されて機械装置の稼働率が１００％に近い高率に維持される。
従って、作業能率あたりの設備コストが低減される。
【００３３】
請求項７の発明装置を適用すると、独立して制御される２組のセンタレス研削機構が共通のベッド上に設置されているので、前記請求項１に係る発明方法を容易に実施して、その効果を充分に発揮させることができる。
特に、上記２組のセンタレス研削機構のそれぞれが研削砥石ドレッサを備えているので、各センタレス研削機構の工程に応じた研削砥石をドレッシングすることができ、しかも、各センタレス研削機構に共通の調整砥石ドレッサが設けられているので、該２組のセンタレス研削機構相互に調整砥石を厳密に正確に同心，同寸にドレッシングすることができ、０．１μｍ未満の超高精度センタレス研削仕上げを可能ならしめる。
【００３４】
請求項８の発明装置によると、２組のセンタレス研削機構が共通のベッドの上に平行に設置され、かつ、該２組のセンタレス研削機構はそれぞれの研削砥石軸および調整砥石軸を同心状に構成され、少なくとも同心状に調整できるようになっているから、予備仕上げの環境条件と超高精度研削仕上げの環境条件とを一致させることが容易である。
請求項９の発明装置によると、予備仕上げされたワークを、最短距離で、最短時間で、超高精度研削仕上げ用のセンタレス研削機構に供給することができ、搬送中にワークの状態が変化することを最小限まで抑制できるので、仕上げ研削の精度向上に有効である。
請求項１０の発明装置によると、ワークの一端に、高精度研削仕上げ、または超高精度研削仕上げすべき端面が有る場合、
端面研削専用の一つの工程を設けなくても、予備仕上げ工程において、または超高精度研削仕上げ工程において、前記の端面を所望の精度で研削仕上げすることができる。
このため、ワーク全体として加工工程が少なく、能率良く低コストでセンタレス研削を行なうことができる。
請求項１１の発明装置によると、２組のセンタレス研削機構がクーラント循環系統を共有しているので構成が簡単で、小形軽量，低コストであるのみでなく、予備仕上げ中のワークと超高精度研削仕上げ中のワークとが同一循環系のクーラントによって冷却されるので、両者の温度条件や潤滑条件が厳密に同様に保たれ、製品の仕上げ精度維持に有効である上に、研削機械装置のメンティナンスが容易である。
【図面の簡単な説明】
【図１】本発明に係る超高精度センタレス研削装置の１実施形態の平面図である。
【図２】上掲の図１の実施形態の正面図である。
【図３】本発明に係る超高精度センタレス研削方法の１実施形態を模式的に描いた工程図である。
【図４】前掲の図１，図２の実施形態におけるクーラントの循環系統図である。
【図５】公知のセンタレス研削機構の１例を示す模式的な正面図である。
【図６】本発明が適用の対称とする、複数のテーパ面を有するワークの模式図である。
【符号の説明】
１・・・調整砥石、１ｆ・・・超高精度調整砥石、１ｐ・・・予備仕上調整砥石、１ｆｍ，１ｐｍ・・・調整砥石駆動モータ、２・・・ブレード、３・・・ワーク、４・・・研削砥石、４ｆ・・・超高精度研削砥石、４ｐ・・・予備仕上研削砥石、４ａ・・・端面、４ｂ・・・第１逃げ研削部、４ｃ・・・第２逃げ研削部、４ｄ・・・第３逃げ研削部、４ｅ・・・テーパ角−θ面、４ｆ・・・テーパ角−φ面、４ｇ・・・テーパ角ψ面、４ｈ・・・円柱状面、５・・・ワーク、５ａ，５ｂ、５ｃ・・・超高精度テーパ面、５ｆ，５ｇ，５ｈ・・・輪状の逃げ部、５ｊ・・・端面、６，６ｆ，６ｐ・・・研削砥石駆動モータ、７，７ｆ，７ｐ・・・研削砥石ドレッサ、９・・・クーラントポンプ、１５・・・分岐管。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technology for centerless grinding a columnar work having a plurality of tapered surfaces having different taper angles with an ultra-high accuracy having a tolerance of less than 0.1 μm. However, only a plurality of designated tapered surfaces are ground with ultra-high precision. Note that the taper angle can take any value between 0 and 180 degrees.
[0002]
[Prior art]
FIG. 5 is a schematic diagram showing a basic structure of the centerless grinding machine.
Although the adjusting whetstone 1 is a grinding wheel, it is a member that functions as a friction wheel rather than reducing the work.
The columnar workpiece 3 is supported by the adjusting whetstone 1 and the blade 4 and is rotated in the direction of an arc arrow a.
The workpiece 3 is rotated in the direction of the circular arrow b by receiving the friction transmission by the rotation of the adjusting grindstone 1 in the direction of the arrow a.
The grinding wheel 4 is a grinding wheel, and contacts the workpiece 3 while rotating in the direction of the circular arrow c at a peripheral speed higher than the rotation of the workpiece in the direction of arrow b, and grinds the workpiece.
The grinding force applied to the work 3 by the grinding wheel 4 acts in a direction to accelerate the rotation of the work 3 in the direction of arrow b. However, since the frictional force with the adjusting grindstone 1 acts as a braking force, the peripheral speed of the work 3 is It becomes almost equal to the peripheral speed of the adjusting grindstone 1.
As a special centerless grinding method, for example, there is a method in which the blade 4 is not provided, as is called a tangential feed, but the three members of "adjustment grindstone / blade / grinding grindstone" form the basis of a centerless grinding grinder. is there.
In the present invention, for convenience of explanation, one set of these three components is referred to as a centerless grinding mechanism.
In addition, the centerless grinding device refers to a complex that is combined with at least one of a coolant (cutting oil) circulation mechanism, a transport mechanism, a drive mechanism, and the like in addition to the centerless grinding mechanism to be a unit of installation. Shall be. However, the definition of the centerless grinding device does not limit the technical scope of the present invention.
[0003]
[Problems to be solved by the invention]
According to the centerless grinding technology, a columnar work can be ground with high precision, and in particular, there is a feature that the roundness is high due to the circular forming action peculiar to the centerless grinding.
As an applied technique, centerless grinding of a rotating surface such as a tapered surface is also known and widely used.
However, there has not yet been developed a technique capable of performing centerless grinding of a workpiece having a particularly complicated tapered surface with ultra-high accuracy having a tolerance of less than 0.01 μm.
FIG. 6 is a front view showing an example of a work having a complicated tapered surface.
The workpiece 5 having an ultra-high precision tapered surface has four ultra-high precision (<0.1 μm) finished surfaces.
That is, a tapered surface 5a having a taper angle θ,
A tapered surface 5b having a taper angle φ> θ,
The taper angle is minus (-ψ), that is, the front opening tapered surface 5c,
The tapered surface where the taper angle is zero, that is, four places including the cylindrical surface 5d is an ultra-high-precision finished surface.
[0004]
Reference numeral 5j denotes an end face, which is not required to be ultra-high precision, and is a high-precision finished surface on the order of microns, and 5e is a screw portion.
In addition, although the oil hole 5i is drilled in the ultra-high precision work 5 of this example, this oil hole has no direct relationship with the ultra-high precision finished surface.
A so-called "escape" is formed between the four ultra-high precision tapered surfaces (5a, 5b, 5c, 5d). The relief portion sandwiched between the tapered surfaces inevitably forms a relief.
The portion indicated by reference numeral 5f is referred to as a first grinding relief portion (specifically, a grinding relief ring-shaped portion). Similarly, 5g is referred to as a second grinding relief ring, and 5h is referred to as a third grinding relief ring. No special system is required for these annular reliefs from the viewpoint of the function of the ultra-high precision work 5.
[0005]
As illustrated in FIG. 6, when trying to centerlessly grind a plurality of tapered surfaces having different taper angles with ultra-high accuracy,
It is possible to carry out in a laboratory by a conventional technique. While a cylindrical surface to be finished with ultra-high accuracy (a portion having a taper angle of zero) is supported by an adjusting grindstone and a blade (see FIG. 5), a taper is formed by a grindstone. What is necessary is just to grind the surface one place at a time with super high precision.
However, when mass-producing industrially, grinding the tapered surfaces at a plurality of locations one by one as described above has the following disadvantages.
[0006]
Since the tapered surfaces at a plurality of locations have different taper angles from each other, the adjustment state of the centerless grinding device must be corrected again each time one location is ground. This requires a high degree of skill and a great deal of labor.
It is conceivable that a plurality of sets of centerless grinding devices having different adjustment states are arranged side by side, and one work is sequentially passed through a plurality of centerless grinding devices. The desired ultra-high accuracy cannot be obtained by passing through a plurality of grinding devices.
(Note) Even if each of the tapered surfaces has the correct shape and dimensions, the precision of the mutual tapered surfaces cannot be obtained.
[0007]
In addition, if the tapered surface at any one location is excessively ground while repeating the ultra-high-precision grinding finish for each location, the workpiece is discarded. Are all wasted.
Now, assuming that the inspection pass rate (yield) of one ultra-high-precision tapered surface grinding is 90%, if such ultra-high-precision tapered surface grinding is repeated four times, the overall inspection pass rate becomes zero. .9 to the fourth power ≒ 2/3.
Even if attention is paid only to the fact that the inspection pass rate (yield) becomes 2/3, it means that the production cost is increased by 33%, which is a problem that cannot be overlooked in industrial production.
[0008]
The present invention has been made in view of the above technical problems,
For example, as shown in FIG. 6, it is intended to provide a technique for grinding a plurality of cylindrical members having ultra-high precision taper surfaces having different taper angles with high efficiency, high yield, and low cost. is there.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the inventor of the present invention has made the following findings as a result of intensively conducting research and research on basic technology.
a. In order to grind a plurality of ultra-high-precision tapered surfaces (5a, 5b, 5c, 5d) with ultra-high accuracy of 0.1 μm or less, a ring-shaped member positioned between these ultra-high-precision taper surfaces is required. (5f, 5g, 5h) must be pre-finished on the order of microns (to achieve the desired ultra-high accuracy)
b. It is desirable to grind the ultra-high-precision tapered surfaces (5a, 5b, 5c, 5d) of the pre-finished work at the same time in the final step (in terms of accuracy and efficiency).
c. To shift to the final finishing process (ultra high precision) without changing the environmental conditions of the pre-finished work as much as possible.
Looking at the results of these studies, it's easy to get the illusion of being a matter of course, but it's like the Columbus egg proverb, `` grinding multiple ultra-high-precision tapered surfaces with industrial profitability. '' It is not a knowledge that can be reached without actually repeating test research with the sense of purpose.
[0010]
The configuration of the invention method according to claim 1 created on the basis of the above-mentioned knowledge is a method for centerless grinding ultra-high precision taper surfaces provided at a plurality of positions of a cylindrical work and having different taper angles from each other. ,
Two sets of centerless grinding mechanisms with almost the same structure and dimensions are installed side by side on a common bed,
By one of the two sets of centerless grinding mechanisms, the "ring-shaped area sandwiched between the ultra-high precision tapered surfaces at the plurality of locations" is preliminarily finished with high precision,
The pre-finished work is transferred to the other centerless grinding mechanism in two sets,
The other centerless grinding mechanism is characterized by simultaneously grinding ultra-high-precision taper surfaces at a plurality of locations with ultra-high precision using a "grinding wheel having a plurality of tapered surfaces integrally joined". I do.
[0011]
According to the method of the first aspect described above,
I. Since a ring-shaped relief portion located in the middle of a plurality of parts to be finished to a tapered surface with ultra-high precision is pre-finished with high precision in advance, it is industrially industrial to finish the plurality of parts with ultra-high precision. Becomes possible.
B. Preliminary finishing and ultra-high-precision finishing are performed by "two sets of centerless grinding mechanisms arranged side by side", so the environmental conditions of the preliminary finishing and the ultra-high-precision finishing are uniform, and errors due to changes in environmental conditions Does not mix.
C. Since a plurality of tapered surfaces are finished in one step by a grinding wheel integrally joined, there is no possibility that a positional error occurs between the tapered surfaces.
Above. B. C. By the comprehensive effect of each item, a plurality of tapered surfaces can be centerlessly ground industrially with high efficiency and low cost, and with ultra-high accuracy with an allowable error of less than 0.1 μm.
[0012]
According to a second aspect of the present invention, in addition to the constituent features of the first aspect, the two sets of centerless mechanisms are installed in parallel with each other.
And, while positioning both grinding wheel axes mutually on substantially the same horizontal plane,
It is characterized in that both adjusting wheel axes are positioned substantially on the same horizontal plane.
According to the method of the present invention described above, the working conditions of the preliminary finishing grinding and the working conditions of the ultra-high-precision finishing grinding can be more strictly matched, and the work can be performed with higher efficiency. it can. As a result, the pass rate (yield) of the final product inspection is improved, and the total cost is effectively reduced.
[0013]
According to a third aspect of the present invention, in addition to the constituent features of the first or second aspect of the present invention, the work preliminarily finished by one of the two sets of centerless grinding mechanisms is provided with a diameter equal to the diameter of the work. And lift it up,
The work is moved almost horizontally in the direction of its axis, and lowered downward,
It is characterized in that it is supplied to the other of the two sets of centerless grinding mechanisms.
According to the method of the third aspect of the present invention described above, since the pre-finishing step and the final grinding finishing step are carried at the shortest distance without providing any steps such as temporary storage and intermediate inspection, ultra-high precision is achieved. Is more easily realized, and the yield is further improved.
[0014]
According to a fourth aspect of the present invention, in addition to the constituent features of the first to third aspects of the present invention, a tapered surface having a taper angle of 90 degrees, that is, a tapered surface among a large number of tapered surfaces formed on a work. If there is a right angled end face,
The present invention is characterized in that the perpendicular end surface is subjected to centerless grinding with a grinding wheel while applying thrust in the axial direction to the end surface opposite to the above-mentioned end surface.
According to the method of the invention described in claim 4 described above, when any one end of a cylindrical work having a plurality of ultra-high-precision tapered surfaces has an end surface to be ground and finished with high accuracy or ultra-high accuracy, During centerless grinding of the work in two steps, the preliminary finishing step and the ultra-high-precision grinding finishing step, the end face can be ground and finished with a desired accuracy, and the number of man-hours can be reduced as compared with the prior art. .
[0015]
According to a fifth aspect of the present invention, in addition to the constituent features of the first to fourth aspects of the present invention, when the workpiece has a tapered surface with a taper angle of 0 °, that is, a cylindrical surface,
The outer peripheral surface of the adjusting grindstone dressed in a cylindrical surface is brought into contact with only the cylindrical surface of the work, and the adjusting grindstone is not brought into contact with the “place where the taper angle is not 0 °” of the work.
According to the method of the invention described above, when one of the plurality of tapered surfaces has a taper angle of zero (that is, a cylindrical surface), this cylindrical surface is stably supported by the blade and the adjusting grinding wheel. As a result, it is possible to more reliably perform ultra-high precision grinding.
[0016]
The structure of the invention method according to claim 6 is, in addition to the constituent elements of the invention method according to claim 1 to claim 5, when a large number of workpieces having the same shape and dimensions are continuously ground.
While one of the two sets of centerless grinding mechanisms pre-finish the subsequent workpiece with high precision,
In parallel with the above, the preceding work is ground with ultra-high precision by the other of the two sets of centerless grinding mechanisms.
After finishing the grinding of the preceding work, the preceding work is unloaded from the other centerless mechanism,
While continuing the rotation of the other centerless grinding mechanism where the work has been lost, while transferring the "subsequent work after preliminary finishing" to the other centerless grinding mechanism,
The "work following the succeeding work" is carried into the one centerless grinding mechanism,
It is characterized in that a large number of works are sequentially and continuously subjected to centerless grinding while repeating the above operations.
According to the method of the present invention described above, a large number of works having the same specifications can be ground with high efficiency and high precision.
When a large number of workpieces are continuously ground by a flow operation according to the sixth aspect, the two sets of centerless mechanisms are continuously operated without alternately stopping, and the operation rate of the machine is 100%. Is maintained at a high rate.
Therefore, equipment cost per work efficiency is reduced.
[0017]
In the configuration of the invention apparatus according to claim 7, two sets of a centerless grinding mechanism including a grinding wheel whose rotation speed is independently controlled, an adjusting wheel whose rotation speed is independently controlled, and a blade are common. It is installed on the bed of
And a grinding wheel dresser is provided in each of the grinding wheels provided in each of the two sets of centerless grinding mechanisms,
A common adjustment wheel dresser is provided for each of the adjustment wheel provided in each of the two sets of centerless grinding mechanisms.
When the apparatus according to the seventh aspect of the present invention described above is applied, two sets of independently controlled centerless grinding mechanisms are installed on a common bed, so that the method according to the first aspect can be easily implemented. Thus, the effect can be sufficiently exhibited.
In particular, since each of the two sets of centerless grinding mechanisms is provided with a grinding wheel dresser, it is possible to dress grinding wheels according to the process of each centerless grinding mechanism, and furthermore, an adjustment grinding wheel common to each centerless grinding mechanism. Since a dresser is provided, the two sets of centerless grinding mechanisms can dress the adjusting whetstone exactly and concentrically and to the same size with each other, thereby enabling ultra-high precision centerless grinding of less than 0.1 μm. .
[0018]
The configuration of the invention apparatus according to claim 8 is such that, in addition to the constituent features of the invention apparatus according to claim 7, the two sets of centerless grinding mechanisms are installed on a common bed in parallel with each other,
The grinding wheel shafts of each of the two sets of centerless grinding mechanisms have a structure that can be fed along a substantially horizontal common plane,
The two sets of centerless grinding mechanisms have a structure in which the adjusting wheel axes of each of the two sets can be adjusted so as to be concentric along a substantially horizontal straight line.
According to the apparatus of the eighth aspect described above, two sets of centerless grinding mechanisms are installed in parallel on a common bed, and the two sets of centerless grinding mechanisms have respective grinding wheel shafts and adjustment wheel shafts. Are formed concentrically and can be adjusted at least concentrically, so that it is easy to match the environmental conditions of the preliminary finishing with the environmental conditions of the ultra-high-precision grinding finishing.
[0019]
According to a ninth aspect of the present invention, in addition to the constituent features of the seventh to eighth aspects of the present invention, a work preliminarily finished by one of the two sets of centerless grinding machines is formed in the diameter direction. Grasp,
Lift the gripped work and move it in the axial direction,
A transport mechanism for supplying the other centerless grinding mechanism is provided.
According to the apparatus of the ninth aspect described above, the pre-finished work can be supplied to the centerless grinding mechanism for ultra-high precision grinding finish in the shortest distance and in the shortest time. Since the change in the state can be suppressed to the minimum, it is effective for improving the precision of the finish grinding.
[0020]
According to a tenth aspect of the present invention, in addition to the constituent features of the seventh to ninth aspects of the present invention, at least one of the two sets of centerless grinding mechanisms is provided on a workpiece. It is characterized by having means for giving a thrust in the axial direction.
According to the apparatus of claim 10 described above, when one end of the workpiece has an end face to be subjected to high-precision grinding or ultra-high-precision grinding,
The end face can be ground and finished with a desired accuracy in the preliminary finishing step or the ultra-high precision grinding finishing step without providing one step dedicated to the end face grinding.
For this reason, centerless grinding can be performed efficiently and at low cost with a small number of processing steps for the entire work.
[0021]
The configuration of the invention apparatus according to claim 11 is such that, in addition to the components of the invention apparatus according to claims 7 to 10, the two sets of centerless grinding mechanisms share one coolant circulation system,
The coolant circulation system includes a common coolant tank, a common pump, and a common filter,
Further, a branch pipe for distributing the coolant discharged from the common pump to the respective centerless grinding mechanisms is provided.
According to the above-described apparatus of the eleventh aspect, since the two sets of centerless grinding mechanisms share the coolant circulation system, the structure is simple, small-sized, light-weight, and low-cost, and the work being pre-finished is performed. And the work in the ultra-high precision grinding finish is cooled by the coolant of the same circulating system, so that both temperature conditions and lubrication conditions are kept strictly the same, which is effective for maintaining the finishing accuracy of the product, The maintenance of the grinding machine is easy.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a plan view showing an embodiment of an ultra-high precision centerless grinding apparatus according to the present invention, and FIG. 2 is a front view of the same. In this embodiment, as shown in FIG. 6 described above, a plurality of tapered surfaces having different taper angles are subjected to centerless grinding with high precision.
(See FIG. 1) On a common bed B, a preliminary finish P composed of two sets of centerless mechanisms of the same shape and the same size and an ultra-high precision finish F are mounted.
1p is an adjustment grindstone for the preliminary finish P, and 1f is an adjustment grindstone for the ultra-high precision finish F. Similarly, 4p is a preliminary finishing grinding wheel, and 4f is an ultra-high precision grinding wheel.
Sr is a common axis of the preliminary finishing adjustment grindstone 1p and the ultra-high precision adjustment grindstone 1f. The common adjustment wheel axis Sp does not move with respect to the common bed B. However, as will be described later in detail with reference to FIG. 2, it is mounted on the bed B via a slide.
In the illustrated state, the two grinding wheels 4p and 4f are adjusted to be concentric with the common axis Sg. However, since the grinding wheel 4p and the grinding wheel 4f are respectively slid in the left-right direction in the drawing (cut feed), they are not always kept concentric, but have a structure that can be adjusted to be concentric. (Adjustable concentrically means that each grinding wheel axis is located on a common plane, and that both grinding wheel axes are moved parallel to each other (cut feed). are doing.
The two grinding wheels 4p and 4f are provided with grinding wheel drive motors 6p and 6f that are independently controlled.
[0023]
The two adjusting wheels 1p and 1f have drive motors 1pm and 1fm that can be controlled independently.
However, as described above, since the two adjusting wheels 1p and 1f are always concentric, these adjusting wheels can be rotationally driven by a single common drive motor. Belonging to the target range.
The two grinding wheels 4p and 4f have dedicated grinding wheel dressers 7p and 7f, respectively.
On the other hand, the two adjusting wheels 1p and 1f have a common adjusting wheel dresser 8. The sharing of the adjusting wheel dresser in this way, together with the concentric installation of the two adjusting wheels 1p and 1f, is a configuration unique to the present invention, and an effect unique to the present invention (described later in detail). To play.
[0024]
In FIG. 2 in which a front view is drawn, two sets of centerless grinding mechanisms (each constituting the ultra-high-precision finishing part F and the preliminary finishing part P described in FIG. 1) overlap one set. Is visible.
The reference numeral 1 denotes an adjusting grindstone, specifically, an overlap between the preliminary finishing adjusting grindstone 1p and the ultra-high precision adjusting grindstone 1f.
Similarly, reference numeral 4 denotes a grinding wheel, and reference numeral 7 denotes a grinding wheel dresser.
Reference numeral 6 denotes a grinding wheel drive motor, and its support member is omitted from the drawing so as to simplify the drawing and facilitate the reading.
In principle, the axis Sr of the adjusting whetstone 1 is fixed to the bed B, but is mounted on the adjusting whetstone feed slide 1s together with the blade 2 in the actual embodiment.
Although overlapping in FIG. 2, the grinding wheels 4 of each of the two sets of centerless grinding mechanisms are mounted on a grinding wheel feed slide 4s.
[0025]
As understood with reference to FIGS. 1 and 2, in the illustrated adjustment state, the axes Sg of the two grinding wheels 4p and 4f are aligned on the same horizontal line.
However, the two grinding wheels 4p and 4f are independently cut and fed in the left and right direction in the figure (by the grinding wheel feed slide 4s).
As described above, when the ultra-high-precision centerless grinding device of the present embodiment is viewed, the axes of the two adjusting wheels match, but the axes of the two grinding wheels generally match. Absent. However, any one of the grinding wheels can be moved in the cutting feed direction (the left-right direction in the figure) so that they can be matched.
The axes of the two adjusting whetstones 1p and 1f always coincide with each other, and at least in the operating state.
[0026]
Next, using the apparatus of the embodiment shown in FIGS. 1 and 2 described above, the work having “a plurality of tapered surfaces having different taper angles” shown in FIG. One example of grinding to less than 1 μm) will be described.
FIG. 3A is a schematic diagram illustrating a preliminary finishing operation, and FIG. 3B is a schematic diagram illustrating an ultra-high-precision grinding finishing operation.
However, in this example, since the pre-finishing work is precision grinding on the order of microns, the work before the pre-finish, the work after the pre-finish, and the ultra-high-precision ground-finished product are taken by hand. At first glance, it is almost indistinguishable.
The work of this example has four ultra-high precision tapered surfaces (see FIG. 6).
The tapered surface denoted by reference numeral 5a has a taper angle θ.
The taper angle of the tapered surface denoted by reference numeral 5b is φ (where φ> θ)
The taper angle of the tapered surface denoted by reference numeral 5c is minus ψ,
The taper angle of the tapered surface denoted by reference numeral 5d is zero (that is, a cylindrical surface).
In order to perform centerless grinding of the above four tapered surfaces with ultra-high accuracy, the ring-shaped relief portions 5f, 5g, and 5h sandwiched between these ultra-high-precision finishes are preliminarily formed with high accuracy (micron order). Perform grinding finish (preliminary finish).
In this example, the tapered surface 5j having a taper angle of 90 degrees (that is, the right-angled end surface) 5j is ground with high precision (micron order). In practicing the present invention, the present invention can be practiced with or without a right-angled end face.
[0027]
Referring to FIG. 3 (A), what is indicated by reference numeral 4p is a grinding wheel that is dressed for performing a preliminary finishing operation.
In this preliminary finishing step, the first grinding relief ring-shaped portion 5f, the second grinding relief ring-shaped portion 5g, and the third relief ring-shaped portion 5h are simultaneously ground with high precision (micron order).
Regardless of whether micron-order precision is required or not in the design specification, in the method of the present invention, in order to finish the tapered part with ultra-high precision in the next step, these ring-shaped relief parts are required to be high. They are ground with precision.
In this example, in this preliminary finishing step, the end face 5j is ground with high precision. This is due to the requirements of the design specification.
Pre-finish grinding wheel 4p
A first clearance grinding portion 4b for grinding the first clearance ring-shaped portion 5f,
A second clearance grinding portion 4c for grinding the second clearance ring-shaped portion 5g,
A third relief grinding portion 4d for grinding the third relief ring-shaped portion 5h,
An end surface grinding portion 4a for grinding the end surface 5j is formed.
Thus, in order to constitute the grinding wheel 4p dedicated to the preliminary finishing work (see FIG. 1), it is very convenient to provide the grinding wheel dresser 7p dedicated to the preliminary finishing portion P.
The preliminary finishing grinding wheel 4p shown in FIG. 3A constitutes a centerless grinding mechanism for the preliminary finishing part P as shown in FIG. A work (not shown in FIG. 1 / because it is very small) is supplied to the preliminary finishing portion P, and preliminary finishing is performed as shown in FIG. In FIG. 1, the axis of the workpiece (not shown) is parallel to the center line Sr of the adjusting grindstone, and is located between the adjusting grindstone 1p and the grinding grindstone 4p.
[0028]
(See FIG. 1.) When the preliminary finishing of the work in the preliminary finish P is completed, the work is gripped in the diametrical direction by a not-shown conveying means, lifted upward (toward the front side of the drawing), and moved in the axial direction of the work ( It is moved to the center of the grinding wheel (parallel to the center line Sr), lowered (in the depth direction of the paper), and supplied to the centerless grinding mechanism of the ultra-high precision finish F.
Thus, the workpiece is transferred from the preliminary finish P to the ultra-high precision finish F in the shortest distance and the shortest time.
Such efficient transport is also effective in improving work efficiency, and is important in that the work is transferred to the next process without changing the environmental conditions of the work.
The subsequent work is supplied to the preliminary finish P from which the work has been sent out, and the work ground and finished in the ultra-high precision finish F is sent to a product inspection process.
In this way, a large number of workpieces are sequentially subjected to centerless grinding in a flow operation.
[0029]
When there is a taper surface (end surface 5j) having a taper angle of 90 degrees as shown in FIG. 3A, a thrust force (thrust) in the direction of arrow s is applied. Thus, the end face can be finished with high precision or ultra-high precision without having to provide an independent end face grinding step.
As a means for giving a thrust, a known means for centerless grinding may be applied.
When there is a tapered surface (cylindrical surface) having a taper angle of zero as in the example shown in FIG. 3, the support of the work and the control of the rotation speed by the blade and the adjusting grindstone are performed only by the cylindrical surface, and the adjusting grindstone is not used. Do not touch the tapered surface of Thereby, the slip between the work and the adjusting grindstone is suppressed to the minimum.
[0030]
The centerless grinding machine is generally provided with a coolant (grinding oil) circulation supply system. FIG. 4 is a schematic piping system diagram of the coolant circulation supply system in the present embodiment.
The coolant pump 9 is rotationally driven by a drive motor 10, sucks and sends the coolant in a coolant tank 11 via a strainer 12, and sends it through a filter 14. 13 is a pressure regulating valve.
A branch pipe 15 is provided on the downstream side of the filter 14, and supplies coolant to the preliminary finish P and the ultra-high precision finish F in parallel.
In this way, by sharing the main part of the coolant circulation system, the overall structure of the grinding device is simple, small, light, and low in cost, and the cooling of the preliminary finish P and the ultra-high precision finish F -Lubrication conditions are exactly equal. Equalizing the environmental conditions of both parts P and F in this manner is effective for obtaining an ultra-high accuracy of less than 0.1 μm.
[0031]
【The invention's effect】
As described above, the configuration and operation of the embodiment of the present invention have been clarified.
I. Since a ring-shaped relief portion located in the middle of a plurality of parts to be finished to a tapered surface with ultra-high precision is pre-finished with high precision in advance, it is industrially industrial to finish the plurality of parts with ultra-high precision. Becomes possible.
B. Preliminary finishing and ultra-high-precision finishing are performed by "two sets of centerless grinding mechanisms arranged side by side", so the environmental conditions of the preliminary finishing and the ultra-high-precision finishing are uniform, and errors due to changes in environmental conditions Does not mix.
C. Since a plurality of tapered surfaces are finished in one step by a grinding wheel integrally joined, there is no possibility that a positional error occurs between the tapered surfaces.
Above. B. C. By the comprehensive effect of each item, a plurality of tapered surfaces can be centerlessly ground industrially with high efficiency and low cost, and with ultra-high accuracy with an allowable error of less than 0.1 μm.
[0032]
According to the method of the second aspect of the invention, the working conditions for the preliminary finish grinding and the working conditions for the ultra-high-precision finish grinding can be more strictly matched, and the work can be performed with higher efficiency. As a result, the pass rate (yield) of the final product inspection is improved, and the total cost is effectively reduced.
According to the method of the third aspect, since the pre-finishing process and the final grinding finishing process are carried at the shortest distance without providing a process such as temporary storage or an intermediate inspection, ultra-high precision can be realized. It becomes easier and the yield is further improved.
According to the fourth aspect of the present invention, when one end of a columnar work having a plurality of ultra-high-precision tapered surfaces has an end surface to be ground with high accuracy or ultra-high accuracy, the work is pre-finished. During the centerless grinding in two steps, the step and the ultra-high-precision grinding finishing step, the end face can be ground and finished with a desired accuracy, and the number of steps can be reduced as compared with the prior art.
According to the invention method of claim 5, when one of the plurality of tapered surfaces has a taper angle of zero (that is, when the surface is a cylindrical surface), the cylindrical surface is stably supported by the blade and the adjusting grinding wheel. It is possible to reliably perform ultra-high precision grinding.
According to the method of the present invention, a large number of works having the same specifications can be ground with high efficiency and high precision.
When a large number of workpieces are continuously ground by a flow operation according to the sixth aspect, the two sets of centerless mechanisms are continuously operated without alternately stopping, and the operation rate of the machine is 100%. Is maintained at a high rate.
Therefore, equipment cost per work efficiency is reduced.
[0033]
When the apparatus according to claim 7 is applied, two sets of independently controlled centerless grinding mechanisms are installed on a common bed, so that the method according to claim 1 can be easily implemented, The effect can be fully exhibited.
In particular, since each of the two sets of centerless grinding mechanisms is provided with a grinding wheel dresser, it is possible to dress grinding wheels according to the process of each centerless grinding mechanism, and furthermore, an adjustment grinding wheel common to each centerless grinding mechanism. Since a dresser is provided, the two sets of centerless grinding mechanisms can dress the adjusting whetstone exactly and concentrically and to the same size with each other, thereby enabling ultra-high precision centerless grinding of less than 0.1 μm. .
[0034]
According to the apparatus of claim 8, two sets of centerless grinding mechanisms are installed in parallel on a common bed, and the two sets of centerless grinding mechanisms concentrically set the respective grinding wheel shafts and adjustment wheel shafts. Since it is configured and can be adjusted at least concentrically, it is easy to match the environmental conditions of the preliminary finishing with the environmental conditions of the ultra-high precision grinding finishing.
According to the ninth aspect of the present invention, the pre-finished work can be supplied to the centerless grinding mechanism for ultra-high-precision grinding in the shortest distance and in the shortest time, and the state of the work changes during conveyance. Since this can be minimized, it is effective for improving the precision of finish grinding.
According to the apparatus of claim 10, when one end of the work has an end face to be subjected to high-precision grinding or ultra-high-precision grinding,
The end face can be ground and finished with a desired accuracy in the preliminary finishing step or the ultra-high precision grinding finishing step without providing one step dedicated to the end face grinding.
For this reason, centerless grinding can be performed efficiently and at low cost with a small number of processing steps for the entire work.
According to the eleventh aspect of the present invention, since two sets of centerless grinding mechanisms share a coolant circulation system, the structure is simple, small and light, and low in cost. Since the work being ground is cooled by the coolant in the same circulation system, the temperature conditions and lubrication conditions of both are kept strictly the same, which is effective for maintaining the finishing accuracy of the product and also maintaining the grinding machine equipment. Is easy.
[Brief description of the drawings]
FIG. 1 is a plan view of an embodiment of an ultra-high precision centerless grinding device according to the present invention.
FIG. 2 is a front view of the embodiment of FIG. 1 above.
FIG. 3 is a process diagram schematically illustrating an embodiment of the ultra-high precision centerless grinding method according to the present invention.
FIG. 4 is a coolant circulation system diagram in the embodiment of FIGS. 1 and 2 described above.
FIG. 5 is a schematic front view showing an example of a known centerless grinding mechanism.
FIG. 6 is a schematic view of a work having a plurality of tapered surfaces to which the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Adjustment whetstone, 1f ... Ultra-precision adjustment whetstone, 1p ... Pre-finishing adjustment whetstone, 1fm, 1pm ... Adjustment whetstone drive motor, 2 ... Blade, 3 ... Work, 4 ... grinding wheel, 4f ... ultra-high precision grinding wheel, 4p ... preliminary finishing grinding wheel, 4a ... end face, 4b ... first relief grinding part, 4c ... second relief grinding part 4d: third relief grinding portion; 4e: taper angle -θ surface; 4f: taper angle -φ surface; 4g: taper angle ψ surface; 4h: cylindrical surface; ..Work, 5a, 5b, 5c: ultra-high precision tapered surface, 5f, 5g, 5h: annular relief portion, 5j: end surface, 6, 6f, 6p: grinding wheel drive motor, 7, 7f, 7p: grinding wheel dresser, 9: coolant pump, 15: branch pipe.

Claims

In a method of centerless grinding ultra-high precision taper surfaces provided at a plurality of positions of a cylindrical workpiece and having different taper angles from each other,
Two sets of centerless grinding mechanisms with almost the same structure and dimensions are installed side by side on a common bed,
By one of the two sets of centerless grinding mechanisms, the "ring-shaped area sandwiched between the ultra-high precision tapered surfaces at the plurality of locations" is preliminarily finished with high precision,
The pre-finished work is transferred to the other centerless grinding mechanism of the two sets,
The other centerless grinding mechanism is characterized by simultaneously grinding ultra-high-precision taper surfaces at a plurality of locations with ultra-high precision using a "grinding wheel having a plurality of tapered surfaces integrally joined". Ultra-high precision centerless grinding method.

The two sets of centerless mechanisms are installed parallel to each other,
And, while positioning both grinding wheel axes mutually on substantially the same horizontal plane,
2. The ultra-high-precision centerless grinding method according to claim 1, wherein both adjusting wheel axes are positioned substantially on the same horizontal plane.

The work preliminarily finished with one of the two sets of centerless grinding mechanisms is gripped in the diameter direction and lifted upward,
The work is moved almost horizontally in the direction of its axis, and lowered downward,
The ultra-high precision centerless grinding method according to claim 1, wherein the supply is performed to the other of the two sets of centerless grinding mechanisms.

In the case where a tapered surface having a taper angle of 90 degrees, that is, a right-angled end surface is included in a large number of tapered surfaces formed on the workpiece,
The ultra-high precision centerless grinding machine according to any one of claims 1 to 3, wherein the perpendicular surface is centerlessly ground by a grinding wheel while applying a thrust in an axial direction to an end surface opposite to the end surface. Grinding method.

When the work has a taper surface with a taper angle of 0 degrees, that is, a cylindrical surface,
The outer peripheral surface of the adjusting grindstone dressed in a cylindrical surface is brought into contact only with the cylindrical surface of the work, and the adjusting grindstone is not brought into contact with the "place where the taper angle is not 0 degree" of the work. Item 4. An ultra-high precision centerless grinding method according to item 4.

When grinding many workpieces of the same shape and dimensions continuously,
While one of the two sets of centerless grinding mechanisms pre-finish the subsequent workpiece with high precision,
In parallel with the above, the preceding work is ground with ultra-high precision by the other of the two sets of centerless grinding mechanisms.
After finishing the grinding of the preceding work, the preceding work is unloaded from the other centerless mechanism,
While continuing the rotation of the other centerless grinding mechanism where the work has been lost, while transferring the "subsequent work after preliminary finishing" to the other centerless grinding mechanism,
The "work following the succeeding work" is carried into the one centerless grinding mechanism,
The ultra-high precision centerless grinding method according to claim 1, wherein a large number of works are sequentially and continuously subjected to centerless grinding while repeating the above operations.

Two sets of a grinding wheel whose rotation speed is controlled independently, an adjustment wheel whose rotation speed is controlled independently, and a centerless grinding mechanism composed of blades are installed on a common bed,
And a grinding wheel dresser is provided in each of the grinding wheels provided in each of the two sets of centerless grinding mechanisms,
An ultra-high-accuracy centerless grinding apparatus, characterized in that a common adjusting wheel dresser is provided for each of the adjusting wheels provided in each of the two sets of centerless grinding mechanisms.

The two sets of centerless grinding mechanisms are installed on a common bed in parallel with each other,
The grinding wheel shafts of each of the two sets of centerless grinding mechanisms have a structure that can be fed along a substantially horizontal common plane,
The ultra-high-precision centerless grinding apparatus according to claim 7, wherein the adjusting wheel shafts of the two sets of centerless grinding mechanisms can be adjusted so as to be concentric along a substantially horizontal straight line. Grinding equipment.

The work preliminarily finished by one of the two sets of centerless grinding devices is gripped in its diameter direction,
Lift the gripped work and move it in the axial direction,
9. The ultra-high precision centerless grinding apparatus according to claim 7, further comprising a transport mechanism for supplying the other centerless grinding mechanism.

The at least one set of centerless grinding mechanisms of the two sets of centerless grinding mechanisms includes a unit that applies axial thrust to the workpiece. Ultra-high precision centerless grinding machine.

The two sets of centerless grinding mechanisms share one coolant circulation system,
The coolant circulation system includes a common coolant tank, a common pump, and a common filter,
The ultra-high-precision centerless grinding device according to claim 7, further comprising a branch pipe for distributing coolant discharged from the common pump to the respective centerless grinding mechanisms. .