JP2004236493A - Ultrasonic drive unit and guide device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic drive unit and a guide device which are stably used for a longer time even under a high-speed condition and a high-load condition. <P>SOLUTION: The ultrasonic drive unit that drives a movable element by vibrations in an ultrasonic area comprises an ultrasonic motor 1 which includes a vibrator 2 producing vibrations, a push member 3 transmitting the vibrations of the vibrator 2 to the movable element, and a driving force transmitting member 15 wherein the push member 3 is pressed and the transmitting member is fixed to the movable element and is driven integrally with the movable element by the vibrations transmitted via the push member 3. The push member 3 and the driving force transmitting member 15 are constituted by ceramics. A ratio of hardness H<SB>1</SB>of a contact face of the push member 3 brought into contact with the transmitting member 15 to hardness H<SB>2</SB>of a contact face of the transmitting member 15 brought into contact with the push member 3, namely H<SB>1</SB>/H<SB>2</SB>, is set to be 0.75 to 1.5. The guide device is equipped with the ultrasonic drive unit, and a stage 13 is driven by the ultrasonic drive unit. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００６０】
なお、実施例１０，１１の案内装置は、駆動力伝達部材１５の表面に下記のような潤滑膜が被覆してあり、実施例１２の案内装置は、押圧部材３及び駆動力伝達部材１５の表面に同様の潤滑膜が被覆してある。
潤滑膜は、以下のようにして被覆した。官能基を有する含フッ素重合体（ダイキン工業株式会社製のデムナム変性品ＳＡ）をＰＦＰＥ油（ＮＯＫクリューバ株式会社製のＩＳ／Ｖ）に８質量％添加して混合した。そして、この混合物をフッ素系の溶剤（旭化学工業株式会社製のＡＫ２２５）で５質量％に希釈した。この溶液を、押圧部材３や駆動力伝達部材１５に塗布し常温乾燥させた後、高温槽等により１００〜２００℃で３０分間加熱処理して潤滑膜を形成した。
【００６１】
使用したセラミックス，サーメット，超硬合金は、以下の通りである。
・窒化ケイ素１：日本タングステン株式会社製 ＮＰＮ−３、ビッカース硬さＨｖ＝１８５０、破壊靱性値Ｋ_ＩＣ＝７．５ＭＰａ・ｍ^１／２
・窒化ケイ素２：ＳＩＮＥＲＡＭＩＣ社製 Ｓ／ＲＢＳＮ、ビッカース硬さＨｖ＝１１００
・ジルコニア１：京セラ株式会社製 Ｚ７０３、ビッカース硬さＨｖ＝１３５０
【００６２】
・ジルコニア２：日本タングステン株式会社製 ＮＰＺ−２、ビッカース硬さＨｖ＝１４５０、破壊靱性値Ｋ_ＩＣ＝７．５ＭＰａ・ｍ^１／２
・ジルコニア３：京セラ株式会社製 Ｚ２１Ｈ０、ビッカース硬さＨｖ＝１１００
・アルミナ１：株式会社日本セラテック製 ＡＪＰＦ、ビッカース硬さＨｖ＝１９００、破壊靱性値Ｋ_ＩＣ＝３．５ＭＰａ・ｍ^１／２
・アルミナ２：京セラ株式会社製 Ａ−６０１Ｄ、ビッカース硬さＨｖ＝１７２０、破壊靱性値Ｋ_ＩＣ＝５．７ＭＰａ・ｍ^１／２ 、曲げ強度＝４００ＭＰａ
【００６３】
・アルミナ３：株式会社ニッカトー製 ＳＳＡ−９９９Ｗ、ビッカース硬さＨｖ＝２０１０、破壊靱性値Ｋ_ＩＣ＝３．５ＭＰａ・ｍ^１／２ 、曲げ強度＝５８８ＭＰａ
・アルミナ４：品川白煉瓦株式会社製 Ａ９６、ビッカース硬さＨｖ＝１３２０
・アルミナ５：株式会社ソディックニューマテリアル製 ＳＡ８１２、ビッカース硬さＨｖ＝１６００、破壊靱性値Ｋ_ＩＣ＝３．２ＭＰａ・ｍ^１／２ 、曲げ強度＝３９０ＭＰａ
【００６４】
・炭化ケイ素：日本ガイシ株式会社製 ＳＣ２０、ビッカース硬さＨｖ＝２８．６ＧＰａ、破壊靱性値Ｋ_ＩＣ＝２．５ＭＰａ・ｍ^１／２ 、曲げ強度＝５８０ＭＰａ
・超硬合金１：住友電気工業株式会社製 Ｍ６１Ｕ（ＷＣ−Ｎｉ−Ｃｒ系）、ビッカース硬さＨｖ＝１２５０、破壊靱性値Ｋ_ＩＣ＝９ＭＰａ・ｍ^１／２
・超硬合金２：日本タングステン株式会社製 ＲＣＣＬ（ＷＣ−ＴｉＣ−ＴａＣ系）、ビッカース硬さＨｖ＝２０００、破壊靱性値Ｋ_ＩＣ＝６．５ＭＰａ・ｍ^１／２ 、曲げ強度＝１０００ＭＰａ
【００６５】
・超硬合金３：ダイジェット工業株式会社製 ＦＢ０１（ＷＣ−Ｃｏ−Ｎｉ系）、ビッカース硬さＨｖ＝２８００、破壊靱性値Ｋ_ＩＣ＝５．５ＭＰａ・ｍ^１／２
・サーメット１：日本タングステン株式会社製 ＤＵＸ４０（ＴｉＣ−ＴａＮ−Ｎｉ−Ｍｏ系）、ビッカース硬さＨｖ＝１４５０、破壊靱性値Ｋ_ＩＣ＝７ＭＰａ・ｍ^１／２ 、曲げ強度＝１６００ＭＰａ
・サーメット２：旭硝子株式会社製 ＵＤ−ＩＩ３５Ｔ（ホウ化物系）、ビッカース硬さＨｖ＝１０００、破壊靱性値Ｋ_ＩＣ＝１７ＭＰａ・ｍ^１／２
【００６６】
次に、案内装置の耐久性の評価方法について説明する。超音波駆動装置によりステージ１３を駆動し、発生した摩耗粉が押圧部材３と駆動力伝達部材１５との間に噛み込まれてステージ１３が移動不能となるまでの時間により案内装置の耐久性を評価した。
その他の条件は以下の通りである。圧電セラミックス板５の材料はチタン酸ジルコン酸鉛系のセラミックスで、その寸法は幅７．５ｍｍ，長さ３０ｍｍ，厚さ３ｍｍである。また、押圧部材３は直径３．０ｍｍ，長さ４．０ｍｍの円柱状で、駆動力伝達部材１５と当接する当接面は曲率半径が７．５ｍｍの球面である。この当接面の最大表面粗さＲ_ｍａｘ は１．５μｍであり、駆動力伝達部材１５の最大表面粗さＲ_ｍａｘ は２．０μｍである。
【００６７】
さらに、案内レール１２はストロークが１００ｍｍのクロスローラガイドであり、ステージ１３の質量は３．５ｋｇである。さらに、予め設定するステージ１３の移動プロファイルは、移動距離５０ｍｍ、加減速度０．０５Ｇ、最高速度１００ｍｍ／ｓに設定した台形制御とした。さらに、超音波モータ１の駆動周波数は４０ｋＨｚとした。
【００６８】
耐久性の評価結果を表１に併せて示す。なお、表１における耐久性の数値は、比較例１の耐久性を１とした場合の相対値で示してある。
表１から分かるように、実施例１〜１２の案内装置は、押圧部材３と駆動力伝達部材１５とを構成する材料が両方ともセラミックスである場合には、Ｈ_１ ／Ｈ_２ の値が０．７５〜１．５であり、押圧部材３と駆動力伝達部材１５とを構成する材料の一方がセラミックスで他方がサーメット又は超硬合金である場合には、０．７５〜２．１であるので、前記Ｈ_１ ／Ｈ_２ の値が前記範囲から外れている比較例１〜４と比べて耐久性が格段に優れていた。
【００６９】
前記Ｈ_１ ／Ｈ_２ の値と案内装置の耐久性との相関性を図３のグラフに示す。なお、グラフ中の○印は、押圧部材３と駆動力伝達部材１５とを構成する材料が両方ともセラミックスである場合を示し、□印は押圧部材３と駆動力伝達部材１５とを構成する材料の一方がセラミックスで他方がサーメット又は超硬合金である場合を示す。また、このグラフにおける耐久性の数値は、比較例１の耐久性を１とした場合の相対値で示してある。
【００７０】
このグラフから、押圧部材３と駆動力伝達部材１５とを構成する材料が両方ともセラミックスである場合には、Ｈ_１ ／Ｈ_２ の値が０．７５〜１．５であると案内装置の耐久性が優れていることが分かる。また、押圧部材３と駆動力伝達部材１５とを構成する材料の一方がセラミックスで他方がサーメット又は超硬合金である場合には、Ｈ_１ ／Ｈ_２ の値が０．７５〜２．１であると案内装置の耐久性が優れていることが分かる。
【００７１】
次に、前述と同様の構成の案内装置において、押圧部材３及び駆動力伝達部材１５を構成する材料の種類を表２に示すように種々変更したものを用意した。すなわち、実施例１３〜２０及び比較例５〜７の案内装置は、押圧部材３及び駆動力伝達部材１５が、それぞれセラミックス，サーメット，及び超硬合金のうちのいずれかの材料で構成されており、両部材３，１５を構成する材料は、破壊靱性値Ｋ_ＩＣ／（ビッカース硬さＨｖ×最大表面粗さＲ_ｍａｘ ^０．５ ）の値が表２に示すような値とされている。この値は、加工や仕上げの際に最大表面粗さＲ_ｍａｘ を調整することによって、種々の値に設定されている。なお、表２に記載の案内装置は、前述のような潤滑膜は備えていない。
【００７２】
【表２】

【００７３】
そして、これらの案内装置を連続運転して、その耐久性を評価した。以下に、案内装置の耐久性の評価方法について説明する。超音波駆動装置によりステージ１３を駆動し、発生した摩耗粉が押圧部材３と駆動力伝達部材１５との間に噛み込まれてステージ１３が移動不能となるまでの時間により案内装置の耐久性を評価した。
【００７４】
その他の条件は以下の通りである。圧電セラミックス板５の材料はチタン酸ジルコン酸鉛系のセラミックスで、その寸法は幅７．５ｍｍ，長さ３０ｍｍ，厚さ３ｍｍである。また、押圧部材３は直径３．０ｍｍ，長さ４．０ｍｍの円柱状で、駆動力伝達部材１５と当接する当接面は、曲率半径が６．５ｍｍの球面である。
【００７５】
さらに、案内レール１２はストロークが１００ｍｍのクロスローラガイドであり、ステージ１３の質量は３．５ｋｇである。さらに、予め設定するステージ１３の移動プロファイルは、移動距離５０ｍｍ、加減速度０．０４Ｇ、最高速度１００ｍｍ／ｓに設定した台形制御とした。さらに、超音波モータ１の駆動周波数は４０ｋＨｚとした。
【００７６】
耐久性の評価結果を表２に併せて示す。なお、表２における耐久性の数値は、比較例５の耐久性を１とした場合の相対値で示してある。
表２から分かるように、実施例１３〜２０の案内装置は、押圧部材３と駆動力伝達部材１５とを構成する材料の破壊靱性値Ｋ_ＩＣ／（ビッカース硬さＨｖ×最大表面粗さＲ_ｍａｘ ^０．５ ）の値が０．００３以上であるので、前記値が０．００３未満である比較例５〜７と比べて耐久性が格段に優れていた。
【００７７】
押圧部材３を構成する材料の前記値と案内装置の耐久性との相関性を図４のグラフに示す。なお、駆動力伝達部材１５はアルミナ１で構成されており、その前記値は０．００３５である。また、このグラフにおける耐久性の数値は、比較例５の耐久性を１とした場合の相対値で示してある。
このグラフから、押圧部材３を構成する材料の前記値が０．００３以上であると、案内装置の耐久性が優れていることが分かる。
【００７８】
次に、前述と同様の構成の案内装置において、板状の駆動力伝達部材１５を構成する材料の種類を表３に示すように種々変更したものを用意した。すなわち、実施例２１〜２８及び比較例８〜１１の案内装置は、押圧部材３が前述のアルミナ３で構成され、駆動力伝達部材１５がセラミックス，サーメット，及び超硬合金のうちのいずれかの材料で構成されている。そして、駆動力伝達部材１５を構成する材料は、曲げ強度×（板厚／最大表面粗さＲ_ｍａｘ ）^２ ×１０^−６の値（以降は「式値」と記す）が表３に示すような値とされている。この式値は、駆動力伝達部材１５を構成する材料の種類，駆動力伝達部材１５の板厚，又は加工や仕上げの際に調整した最大表面粗さＲ_ｍａｘ によって、種々の値に設定されている。なお、表３に記載の案内装置は、前述のような潤滑膜は備えていない。
【００７９】
【表３】

【００８０】
使用したセラミックス，サーメット，超硬合金は、前述した材料又は以下に示す材料である。
・アルミナ１Ｂ：株式会社日本セラテック製 ＡＨＰＦ、曲げ強度＝７００ＭＰａ
・窒化ケイ素３：日立金属株式会社製、曲げ強度＝７５０ＭＰａ
・サイアロン１：日立金属株式会社製 ＨＣＮ−４０、曲げ強度＝８３０ＭＰａ
そして、これらの案内装置を連続運転して、その耐久性を評価した。以下に、案内装置の耐久性の評価方法について説明する。
【００８１】
超音波駆動装置によりステージ１３を駆動し、発生した摩耗粉が押圧部材３と駆動力伝達部材１５との間に噛み込まれてステージ１３が移動不能となるまでの時間により案内装置の耐久性を評価した。
その他の条件は以下の通りである。圧電セラミックス板５の材料はチタン酸ジルコン酸鉛系のセラミックスで、その寸法は幅７．５ｍｍ，長さ３０ｍｍ，厚さ３ｍｍである。また、押圧部材３は前述のアルミナ３で構成され、直径３．０ｍｍ，長さ４．０ｍｍの円柱状で、駆動力伝達部材１５と当接する当接面は曲率半径が７．０ｍｍの球面である。この当接面の算術平均表面粗さＲａは０．１μｍである。
【００８２】
さらに、案内レール１２はストロークが２００ｍｍのクロスローラガイドであり、ステージ１３の質量は３．５ｋｇである。さらに、予め設定するステージ１３の移動プロファイルは、移動距離１００ｍｍ、最高速度１００ｍｍ／ｓに設定した台形制御とした。さらに、超音波モータ１の駆動周波数は４０ｋＨｚとした。
【００８３】
耐久性の評価結果を表３に併せて示す。なお、表３における耐久性の数値は、比較例８の耐久性を１とした場合の相対値で示してある。表３から分かるように、実施例２１〜２８の案内装置は、比較例８〜１１と比べて耐久性が格段に優れていた。
前記式値と案内装置の耐久性との相関性を図５のグラフに示す。なお、このグラフにおける耐久性の数値は、比較例８の耐久性を１とした場合の相対値で示してある。このグラフから、前記式値が３００ＭＰａ以上であると案内装置の耐久性が優れていることが分かる。
【００８４】
次に、前述と同様の構成の案内装置において、押圧部材３及び駆動力伝達部材１５を構成する材料の種類を表４に示すように種々変更したものを用意した。すなわち、実施例３０，３１の案内装置は、押圧部材３が加圧焼結したセラミックス（アルミナ）で構成されており、実施例３２の案内装置は、押圧部材３が常圧焼結したセラミックス（アルミナ）で構成されている。また、実施例２９，３３の案内装置は、押圧部材３及び駆動力伝達部材１５が常圧焼結したセラミックス（アルミナ）で構成されている。なお、押圧部材３を構成する材料の硬さＨ_１ と駆動力伝達部材１５を構成する材料の硬さＨ_２ の比Ｈ_１ ／Ｈ_２ は、表４に示すような値とされている。
【００８５】
【表４】

【００８６】
表４に記載のセラミックスは、以下の通りである。
・アルミナ６：日本タングステン株式会社製 ＮＰＡ−２、ビッカース硬さＨｖ＝２０００
・アルミナ７：加圧焼結品（アルミナ含有率＝９９．５％）、ビッカース硬さＨｖ＝１９００、平均結晶粒径＝５μｍ
・アルミナ８：加圧焼結品（アルミナ含有率＝９９．９％）、ビッカース硬さＨｖ＝２０１０、平均結晶粒経＝０．５μｍ
・アルミナ９：常圧焼結品（アルミナ含有率＝９５％）、ビッカース硬さＨｖ＝１５００、平均結晶粒径＝４５μｍ
そして、これらの案内装置を連続運転して、その耐久性を評価した。案内装置の耐久性の評価方法は、前述した実施例１〜１２の案内装置の評価方法と全く同様であるので、その説明は省略する。
【００８７】
耐久性の評価結果を表４に併せて示す。なお、表４における耐久性の数値は、前述の比較例１の耐久性を１とした場合の相対値で示してある。表４から、押圧部材３又は駆動力伝達部材１５が加圧焼結したアルミナで構成されていると、案内装置の耐久性が優れていることが分かる。これは、加圧焼結したアルミナは結晶粒径が小さいため、耐摩耗性が優れていることが原因であると考えられる。
【００８８】
そこで、平均結晶粒径が種々異なるアルミナで押圧部材３を構成した案内装置を用意して、実施例１〜１２の案内装置の評価方法と全く同様の方法で耐久性を評価した。駆動力伝達部材１５はアルミナ６で構成し、その最大表面粗さＲ_ｍａｘ は２．０μｍとした。また、押圧部材３の最大表面粗さＲ_ｍａｘ は０．２５μｍとした。
【００８９】
評価結果を図６のグラフに示す。なお、このグラフにおける耐久性の数値は、前述の比較例１の耐久性を１とした場合の相対値で示してある。グラフから、焼結したアルミナの平均結晶粒径が４０μｍ以下であると、案内装置の耐久性が優れていることが分かる。そして、平均結晶粒径が２０μｍ以下であると、案内装置の耐久性がより優れており、５μｍ以下であるとさらに優れていることが分かる。なお、加圧焼結したアルミナの種類は、特に限定されるものではない。
【００９０】
次に、前述と同様の構成の案内装置において、押圧部材３に当接する駆動力伝達部材１５の当接面に潤滑膜を被覆したものを用意した。すなわち、押圧部材３と駆動力伝達部材１５とは表４に示すような材料で構成されており、押圧部材３を構成する材料の硬さＨ_１ と駆動力伝達部材１５を構成する材料の硬さＨ_２ の比Ｈ_１ ／Ｈ_２ は、表４に示すような値とされている。また、押圧部材３に当接する駆動力伝達部材１５の当接面は、活性化処理が施された後に潤滑膜が被覆されている。なお、駆動力伝達部材１５に当接する押圧部材３の当接面には、潤滑膜は被覆されていない。
【００９１】
潤滑膜は、以下のようにして被覆した。まず、駆動力伝達部材１５の当接面を脱脂洗浄した後、活性化処理を施した。活性化処理の内容は、以下の通りである。表４の実施例３４の案内装置の場合は、前記当接面を３００℃に加熱した後にＮＦ_３ ガスを接触させた。実施例３５の案内装置の場合は、前記当接面に大気圧下においてプラズマ処理を施した。実施例３６の案内装置の場合は、前記当接面に減圧下においてアルゴンプラズマ処理を施した。比較例１２の案内装置の場合は、活性化処理を施すことなく潤滑膜を被覆した。
【００９２】
なお、実施例３４ではＮＦ_３ ガスによって当接面の活性化を行ったが、活性化に使用するハロゲン系ガスの種類は特に限定されるものではなく、ＢＦ_３ ，ＣＦ_４ ，ＣＣｌ_４ ，ＣＢｒ_４ ，ＣＩ_４ ，ＣＨＦ_３ ，ＣＨＣｌ_３ ，ＣＨＢｒ_３ ，ＣＨＩ_３ ，ＳＦ_６ ，Ｆ_２ 等を用いることができる。
また、実施例３５で用いたプラズマ処理とは、被処理物をプラズマに暴露することによって、被処理物の表面に物理吸着又は化学吸着している有機物にＯ_２ プラズマを作用させ、ＣＯ，ＣＯ_２ ，Ｈ_２ Ｏを形成させて、被処理物の表面をクリーニングする方法である。この方法は、減圧中又は大気中の両方で行うことが可能である。しかし、被処理物表面に汚れとして有機物のみならず無機物が存在する場合には、Ｏ_２ プラズマでは十分に除去することができない。
【００９３】
このような場合には減圧下でプラズマを発生させ、イオンシース中でイオンを加速し、汚れにガスイオンを衝突させて物理的作用でクリーニングするとよい。いずれのプラズマ処理においても、空気，酸素，アルゴン，ハロゲン系ガス，又はこれらの混合ガスが使用可能である。
次に、ＰＦＰＥ油（ダイキン工業株式会社製デムナムＳ−２００）をフッ素系溶剤（旭化学工業株式会社製ＡＫ２２５）で２質量％に希釈したものを、活性化した駆動力伝達部材１５の当接面に塗布した。そして、常温乾燥させた後、高温槽等により１００〜２００℃で３０分〜１時間加熱処理して潤滑膜を形成した。いずれの実施例及び比較例においても、潤滑膜の厚さは０．７μｍとした。
【００９４】
なお、この潤滑膜の厚さは、ＰＦＰＥ油のフッ素系溶剤への溶解濃度によって制御することが可能である。また、その厚さは、予め作成した検量線を用いて赤外線分光分析計によって検定することができる。潤滑膜の被覆方法は特に限定されるものではない。
そして、これらの案内装置を連続運転して、その耐久性を評価した。案内装置の耐久性の評価方法は、前述した実施例１〜１２の案内装置の評価方法と全く同様であるので、その説明は省略する。
【００９５】
評価結果を表４に示す。なお、表４における耐久性の数値は、前述の比較例１の耐久性を１とした場合の相対値で示してある。表４から分かるように、実施例３４〜３６の案内装置は、駆動力伝達部材１５の当接面に活性化処理を施した後に潤滑膜を被覆しているので、活性化処理を施さずに潤滑膜を被覆した比較例１２の案内装置と比べて、耐久性が格段に優れていた。
【００９６】
次に、前述と同様の構成の案内装置において、押圧部材３及び駆動力伝達部材１５を構成する材料の種類を表５に示すように種々変更したものを用意した。すなわち、実施例３７〜４１及び比較例１３，１４の案内装置は、押圧部材３及び駆動力伝達部材１５がセラミックス又はサーメットで構成されており、押圧部材３を構成する材料の硬さＨ_１ と駆動力伝達部材１５を構成する材料の硬さＨ_２ の比Ｈ_１ ／Ｈ_２ は、表５に示すような値とされている。
【００９７】
【表５】

【００９８】
使用したセラミックス及びサーメットは、前述した材料又は以下に示す材料である。すなわち、窒化ケイ素４は日立金属株式会社製ＨＳＮ６５であり、ビッカース硬さＨｖは１５００で、熱伝導率は６５Ｗ／ｍ・Ｋである。また、窒化ケイ素５〜８はＡｌ_２ Ｏ_３ 及びＹ_２ Ｏ_３ を合計で１０質量％含有する窒化ケイ素であり、焼結温度２０００℃で焼結して製造したものである。そして、製造時において、焼結後の冷却速度を２５〜１５０℃／ｈの範囲で変化させて、焼結助剤成分の結晶化率を変えることにより、熱伝導率を変化させたものである。窒化ケイ素５〜８の熱伝導率を始めとする各種物性を、表６にまとめて示す。なお、表５に記載の案内装置は、前述のような潤滑膜は備えていない。
【００９９】
【表６】

【０１００】
そして、これらの案内装置を連続運転して、その耐久性を評価した。案内装置の耐久性の評価方法は、前述した実施例１〜１２の案内装置の評価方法と全く同様であるので、その説明は省略する。
耐久性の評価結果を表５に併せて示す。なお、表５における耐久性の数値は、前述の比較例１の耐久性を１とした場合の相対値で示してある。表５から、駆動力伝達部材１５を構成する窒化ケイ素の熱伝導率が大きい方が案内装置の耐久性が優れている、という傾向があることが分かる。
【０１０１】
そこで、熱伝導率が種々異なる窒化ケイ素で駆動力伝達部材１５を構成した案内装置を用意して、実施例１〜１２の案内装置の評価方法と全く同様の方法で耐久性を評価した。いずれの案内装置も、押圧部材３はアルミナ１で構成し、その最大表面粗さＲ_ｍａｘ は０．２５μｍとした。また、駆動力伝達部材１５の最大表面粗さＲ_ｍａｘ は２．０μｍとした。
【０１０２】
評価結果を図７のグラフに示す。なお、このグラフにおける耐久性の数値は、前述の比較例１の耐久性を１とした場合の相対値で示してある。グラフから、駆動力伝達部材１５を構成する窒化ケイ素の熱伝導率が４５Ｗ／ｍ・Ｋ以上であると、案内装置の耐久性が優れていることが分かる。
なお、高熱伝導性のセラミックスを用いて押圧部材や駆動力伝達部材を構成する場合には、その破壊靱性値Ｋ_ＩＣを４ＭＰａ・ｍ^１／２ 以上とすることが好ましい。そうすれば、超音波駆動装置の稼動中に押圧部材及び駆動力伝達部材に繰り返し荷重が作用してもクラックや破損が生じにくく、より長期間にわたって安定して使用することができる。
【０１０３】
セラミックスの熱伝導性を向上させるためには、焼結体内の格子振動の伝播を阻害する要因、すなわち粒界，内部欠陥，結晶構造などを最適化する必要がある。
内部欠陥の中でも特に有害なものは焼結体内部に残存する空孔であり、これらが多量に存在すると焼結体の熱伝導率は著しく低下する。したがって、空孔率を低減することにより熱伝導率を効果的に向上させることができる。セラミックスの熱伝導率を十分に高いものとするためには、空孔率を２体積％以下とすることが好ましい。空孔率を低減するためには、セラミックスをＨＩＰ焼結法，ガス圧焼結法等の加圧焼結法によって製造することが好ましい。
【０１０４】
また、セラミックスの熱伝導率を低下させる要因の一つとして、結晶粒界に存在する焼結助剤相が考えられる。窒化ケイ素の場合には、焼結助剤としては、一般にＡｌ_２ Ｏ_３ ，ＭｇＯ，ＣｅＯ等の金属酸化物やＹ_２ Ｏ_３ ，Ｙｂ_２ Ｏ_３ ，Ｌａ_２ Ｏ_３ 等の希土類酸化物が用いられ、焼結体全体の２０質量％を上限として添加されることが多い。特に、Ａｌ_２ Ｏ_３ −Ｙ_２ Ｏ_３ 系のものやＡｌ_２ Ｏ_３ −ＭｇＯ系のものが多く用いられ、これらは非晶質の状態で焼結体の粒界に存在している。
【０１０５】
一般に、非晶質構造の固体は格子振動が伝播し難く、熱伝導率が低いので、焼結助剤が非晶質の状態で多量に粒界に存在する窒化ケイ素は、熱伝導率が低くなる。したがって、焼結助剤部分の結晶化度を高めることにより、焼結助剤部分での熱伝導性を改善し、高熱伝導性の窒化ケイ素を得ることができる。焼結助剤の結晶化度を高めるためには、焼結後の冷却速度を調整すればよい。すなわち、冷却速度が速いと焼結助剤成分の原子配列が間に合わず、高温状態である非晶質をそのまま引き継いだ形で常温相を構成するが、冷却速度を遅くすれば結晶化の進んだ常温相となる。
【０１０６】
セラミックスの熱伝導率を十分に高いものとするためには、焼結体内に含まれる粒界相中の結晶質相の割合を１０体積％以上とすることが好ましい。このとき、さらに熱伝導率を向上させるためには、焼結助剤成分としてＬａ，Ｃｅ，Ｐｒ，Ｎｄ，Ｈｏ等のランタノイド系列から選ばれた酸化物を使用することが好ましい。
【０１０７】
次に、前述と同様の構成の案内装置において、押圧部材３を構成する材料の種類を表７に示すように種々変更したものを用意した。すなわち、実施例４２〜４６及び比較例１５〜１７の案内装置は、押圧部材３が後述のようにして製造したアルミナで構成されている。そして、押圧部材３を構成するアルミナについては、相当円直径が１０μｍ以下であるポアの１ｍｍ^２ 当たりの個数と相当円直径が３０μｍ以上であるポアの１ｍｍ^２ 当たりの個数とが、表７に示すような値とされている。なお、駆動力伝達部材１５は、全てＣｏｏｒｓＴｅｋ Ｌｔｄ社製のアルミナ（ＦＧ−９９５）で構成されている。
【０１０８】
【表７】

【０１０９】
押圧部材３を構成するアルミナの製造方法の一例を、以下に示す。主原料であるアルミナ粉末に酸化マグネシウム，酸化イットリウム等の焼結助剤を添加し、さらに溶剤，有機バインダー，可塑剤，分散剤を添加してスラリーを調整した。このスラリーを成形し、必要に応じて大気中で５００〜１５００℃で焼成した後、常圧から真空までの還元雰囲気下で１７００〜１９００℃で焼結して、アルミナ焼結体を得た。そして、得られた焼結体にバレル加工，研磨等を施して、形状を整えるとともに、表７に記載のようなポア分布を有する状態に表面を仕上げた。なお、表７に記載の案内装置は、前述のような潤滑膜は備えていない。
【０１１０】
そして、これらの案内装置を連続運転して、その耐久性を評価した。以下に、案内装置の耐久性の評価方法について説明する。
超音波駆動装置によりステージ１３を駆動し、発生した摩耗粉が押圧部材３と駆動力伝達部材１５との間に噛み込まれてステージ１３が移動不能となるまでの時間により案内装置の耐久性を評価した。
【０１１１】
その他の条件は以下の通りである。圧電セラミックス板５の材料はチタン酸ジルコン酸鉛系のセラミックスで、その寸法は幅７．５ｍｍ，長さ３０ｍｍ，厚さ３ｍｍである。また、押圧部材３は前述のアルミナ焼結体で構成され、直径３．０ｍｍ，長さ４．０ｍｍの円柱状で、駆動力伝達部材１５と当接する当接面は曲率半径が１０ｍｍの球面である。この当接面の最大表面粗さＲ_ｍａｘ は１．５μｍであり、駆動力伝達部材１５の最大表面粗さＲ_ｍａｘ は２．０μｍである。
【０１１２】
さらに、案内レール１２はストロークが１００ｍｍのクロスローラガイドであり、ステージ１３の質量は３．５ｋｇである。さらに、予め設定するステージ１３の移動プロファイルは、移動距離６０ｍｍ、加減速度０．０５Ｇ、最高速度１１０ｍｍ／ｓに設定した台形制御とした。さらに、超音波モータ１の駆動周波数は４０ｋＨｚとした。
【０１１３】
耐久性の評価結果を表７に併せて示す。なお、表７における耐久性の数値は、比較例１５の耐久性を１とした場合の相対値で示してある。表７から、実施例の案内装置は比較例と比べて、耐久性が格段に優れていることが分かる。
なお、本発明において使用可能なセラミックス，サーメット，及び超硬合金の種類は、特に限定されるものではない。
【０１１４】
セラミックスとしては、窒化ケイ素（Ｓｉ_３ Ｎ_４ ）系， ジルコニア（ＺｒＯ_２ ）系， アルミナ（Ａｌ_２ Ｏ_３ ）系， 炭化ケイ素（ＳｉＣ）系，窒化アルミニウム（ＡｌＮ）系，炭化ホウ素（Ｂ_４ Ｃ）系， ホウ化チタン（ＴｉＢ_２ ）系，窒化ホウ素（ＢＮ）系， 炭化チタン（ＴｉＣ）系， 窒化チタン（ＴｉＮ）系、又はこれらのうち２種以上を複合させたセラミック系複合材料などを例示できる。
【０１１５】
このようなセラミックスには、破壊靱性や機械的強度などを向上させるために、繊維状充填材を配合することができる。繊維状充填材の種類は特に限定されるものではないが、炭化ケイ素ウィスカー，窒化ケイ素ウィスカー， アルミナウィスカー，窒化アルミニウムウィスカー等を例示できる。
また、サーメット及び超硬合金とは、周期律表のＩＶｂ族，Ｖｂ族，ＶＩｂ族に属する９種類の金属（Ｔｉ，Ｚｒ，Ｈｆ，Ｖ，Ｎｂ，Ｔａ，Ｃｒ，Ｍｏ，Ｗ）の炭化物粉末と鉄，コバルト，ニッケル等の鉄族金属とを混合して焼結した合金である。
【０１１６】
サーメットとしては、例えば、ＴｉＣ−Ｎｉ系，ＴｉＣ−Ｍｏ−Ｎｉ系，ＴｉＣ−Ｍｏ_２ Ｃ−Ｎｉ系，ＴｉＣ−Ｍｏ_２ Ｃ−ＺｒＣ−Ｎｉ系，Ｍｏ_２ Ｃ−Ｎｉ系，Ｔｉ（Ｃ，Ｎ）−Ｍｏ_２ Ｃ−Ｎｉ系，ＴｉＣ−ＴｉＮ−Ｍｏ_２ Ｃ−Ｎｉ系，ＴｉＣ−ＴｉＮ−Ｍｏ_２ Ｃ−ＴａＣ−Ｎｉ系，ＴｉＣ−ＴｉＮ−Ｍｏ_２ Ｃ−ＷＣ−ＴａＣ−Ｎｉ系，ＴｉＣ−ＷＣ−Ｎｉ系，Ｔｉ（Ｃ，Ｎ）−ＷＣ−Ｎｉ系，ＴｉＣ−Ｍｏ系，Ｔｉ（Ｃ，Ｎ）−Ｍｏ系，ホウ化物系（ＭｏＢ−Ｎｉ系，Ｂ_４ Ｃ／（Ｗ，Ｍｏ）Ｂ_２ 系等）等があげられる。
【０１１７】
なお、Ｔｉ（Ｃ，Ｎ）−Ｍｏ_２ Ｃ−Ｎｉ系，Ｔｉ（Ｃ，Ｎ）−ＷＣ−Ｎｉ系，及びＴｉ（Ｃ，Ｎ）−Ｍｏ系はそれぞれ、ＴｉＣ−Ｍｏ_２ Ｃ−Ｎｉ系，ＴｉＣ−ＷＣ−Ｎｉ系，及びＴｉＣ−Ｍｏ系を窒素ガス中で焼結したものである。
また、超硬合金としては、例えば、ＷＣ−Ｎｉ系，ＷＣ−Ｃｒ_３ Ｃ_２ −Ｍｏ_２ Ｃ−Ｎｉ系，ＷＣ−Ｔｉ（Ｃ，Ｎ）−ＴａＣ系，ＷＣ−Ｔｉ（Ｃ，Ｎ）系，Ｃｒ_３ Ｃ_２ −Ｎｉ系等がある。
【０１１８】
さらに、本発明において使用可能な官能基を有する含フッ素重合体の種類は特に限定されるものではないが、フルオロポリエーテル重合体やポリフルオロアルキル重合体が好ましい。
フルオロポリエーテル重合体としては、下記の化学式（化１）で示される繰り返し単位を有する、数平均分子量が１０００〜５００００の重合体があげられる。なお、このフルオロポリエーテル重合体は、少なくとも一方の分子末端に、後述する官能基を有している。
【０１１９】
【化１】

【０１２０】
また、ポリフルオロアルキル重合体としては、下記の化学式（化２）に示すものがあげられる。式中のＹは金属に対して親和性の高い官能基であり、例えば、エポキシ基，アミノ基，カルボキシル基，水酸基，メルカプト基，イソシアネート基，スルフォン基，エステル基等が好ましい。
【０１２１】
【化２】

【０１２２】
ポリフルオロアルキル重合体としては、化２に示すものの他、例えば、下記の化学式（化３，４）に示すものも好適に使用することができる。
【０１２３】
【化３】

【０１２４】
【化４】

【０１２５】
このような官能基は、潤滑膜が押圧部材や駆動力伝達部材の表面に被覆された際に、押圧部材や駆動力伝達部材を構成する材料と結合するので、押圧部材や駆動力伝達部材の表面と強く結合した潤滑膜が形成される。なお、一つの分子に官能基を複数有する含フッ素重合体の場合は、そのうち少なくとも一つが押圧部材や駆動力伝達部材の表面と結合していればよい。
【０１２６】
前記含フッ素重合体は、上に例示したものを単独で用いてもよいし２種以上を併用してもよい。２種以上を併用する場合は、その官能基同士が反応して前記含フッ素重合体がより高分子量化するように、含フッ素重合体の種類（官能基の種類）の組合せを選択することが好ましい。含フッ素重合体がより高分子量化すれば、より耐摩耗性の優れた潤滑膜を得ることができる。
【０１２７】
このような官能基を有する含フッ素重合体の具体例としては、例えば、デュポン株式会社製のクライトックス１５７ＦＳＬ，１５７ＦＳＭ，１５７ＦＳＨ、ダイキン工業株式会社製のデムナム変性品ＳＡ，ＳＨ，ＳＹ−３，ＳＰ、アウジモント株式会社製のフォンブリンＺ ＤＥＡＬ，Ｚ ＤＩＡＣ，Ｚ ＤＩＳＣＯ，Ｚ ＤＯＬ，Ｚ ＤＯＬ ＴＸ２０００等があげられる。
【０１２８】
また、ＰＦＰＥ油の種類は特に限定されるものではないが、例えば、ダイキン工業株式会社製のＳ−６５，Ｓ−１００，Ｓ−２００、デュポン株式会社製のクライトックス１４３ＡＢ，１４３ＡＣ，１４３ＡＤ、ＮＯＫクリューバ株式会社製のＪ４００，ＩＥＬ／Ｖ，ＩＭＩ／Ｖ，ＩＳ／Ｖ、アウジモント株式会社製のフォンブリンＹ２５，Ｙ４５，ＹＲ，ＹＬＶＡＣ１６／６，ＹＬＶＡ２５／６，ＹＨＶＡＣ４０／１１，ＹＨＶＡＣ１４０／１３等があげられる。
【０１２９】
潤滑膜を形成する方法は、特に限定されるものではなく、例えば、押圧部材や駆動力伝達部材の表面に、官能基を有する含フッ素重合体とＰＦＰＥ油との混合物を塗布又は噴霧する方法や、押圧部材や駆動力伝達部材を前記混合物に浸漬する方法等がある。
官能基を有する含フッ素重合体とＰＦＰＥ油との混合物の一例をあげると、官能基を有する含フッ素重合体をＰＦＰＥ油に２〜１５質量％添加し、これをフッ素系の溶剤で１〜１５質量％に希釈したもの等が好適である。
【０１３０】
次に、この混合物を塗布した押圧部材や駆動力伝達部材を常温乾燥させた後、恒温槽等に入れ１００〜２００℃で３０分程度熱処理を施すことによって、潤滑膜を形成させることができる。
なお、このような潤滑膜を設ける処理は必要に応じて数回繰り返してもよく、潤滑膜を最終的に、例えば０．３μｍ以上の膜厚に形成する。この膜厚は、官能基を有する含フッ素重合体及びＰＦＰＥ油の前記フッ素系の溶剤への溶解濃度によって制御することも可能である。
【０１３１】
このような方法により、押圧部材や駆動力伝達部材の表面に潤滑膜を好適な膜厚で形成することができる。
また、前述のように熱処理によって溶媒を除去しておけば、超音波駆動装置の作動時に不要な発塵が発生することがない。特に、最終の熱処理によって、使用環境での発塵やアウトガスを抑制できる。
【０１３２】
なお、官能基を有する含フッ素重合体をフッ素系の溶剤で希釈したものを先に被覆し、恒温槽等で加熱して押圧部材や駆動力伝達部材の母材である金属に前記含フッ素重合体が有する官能基を反応させて、金属と結合した官能基を有する含フッ素重合体の層を形成し、その後にＰＦＰＥ油をフッ素系の溶剤で希釈したものを被覆して、前記官能基を有する含フッ素重合体の層の上にＰＦＰＥ油の層を形成して、潤滑膜を二層構造としてもよい。
【０１３３】
【発明の効果】
以上のように、本発明の超音波駆動装置及び案内装置は、高速条件下や高荷重条件下においても長期間にわたって安定して使用することが可能である。
【図面の簡単な説明】
【図１】本発明に係る超音波駆動装置に使用される超音波モータの構造を説明する図である。
【図２】本発明に係る案内装置の一実施形態を示す平面図である。
【図３】押圧部材を構成する材料の硬さＨ_１ 及び駆動力伝達部材を構成する材料の硬さＨ_２ の比Ｈ_１ ／Ｈ_２ と案内装置の耐久性との相関を示すグラフである。
【図４】押圧部材を構成する材料の破壊靱性値Ｋ_ＩＣ／（ビッカース硬さＨｖ×最大表面粗さＲ_ｍａｘ ^０．５ ）の値と案内装置の耐久性との相関を示すグラフである。
【図５】駆動力伝達部材の曲げ強度×（板厚／最大表面粗さＲ_ｍａｘ ）^２ ×１０^−６の値と案内装置の耐久性との相関を示すグラフである。
【図６】アルミナの平均結晶粒径と案内装置の耐久性との相関を示すグラフである。
【図７】窒化ケイ素の熱伝導率と案内装置の耐久性との相関を示すグラフである。
【符号の説明】
１ 超音波モータ
２ 振動体
３ 押圧部材
１２ 案内レール
１３ ステージ
１５ 駆動力伝達部材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic drive device that drives a movable body using vibrations in an ultrasonic region, and a guide device that drives a movable body using the ultrasonic drive device, and in particular, relates to a semiconductor manufacturing apparatus (transport apparatus, exposure apparatus) Etc.), an ultrasonic drive device and a guide device suitable for precision processing machines, precision measurement devices, and the like.
[0002]
[Prior art]
Generally, an ultrasonic motor generates a driving force using a piezoelectric material, and includes a vibrating body that generates vibration in an ultrasonic region, and a pressing member that transmits the vibration of the vibrating body to a movable body. In recent years, various devices have been devised with respect to the shape, structure, material, and the like for higher performance.
Ultrasonic motors have characteristics such as being small, capable of obtaining a large driving force due to friction drive, and being usable for highly accurate positioning due to small amplitude of vibration. Therefore, utilization as a driving means of a movable body that performs a linear motion, a rotary motion, and the like has been promoted.
In addition, the pressing member of the ultrasonic motor is required to have the following characteristics in order to frictionally drive a partner member such as a movable body.
[0003]
(1) Excellent wear resistance against friction with mating members
(2) It is difficult to adhere to the mating member
(3) It is hard to damage the partner member
As a conventional example of such an ultrasonic motor, there is one described in Japanese Utility Model Laid-Open No. 2-94686, for example. In this ultrasonic motor, the pressing member is formed of polyimide resin, glass, or ceramics (alumina, silicon carbide, or the like). Further, Japanese Patent Application Laid-Open No. 7-273384 discloses an ultrasonic motor in which a pressing member is formed of a glass material such as quartz glass or soda glass or a ceramic mainly containing alumina, zirconia, and silicon carbide. Further, Japanese Patent Application Laid-Open No. 2002-27768 discloses that a pressing member is formed of alumina ceramics having an alumina content of 99.5% by mass or more and a Vickers hardness of 15.2 GPa or more, and which is in contact with a movable body. An ultrasonic motor in which the contact surface has an arithmetic average roughness (Ra) of 0.2 μm or less is disclosed.
[0004]
On the other hand, an ultrasonic driving device including the above-described ultrasonic motor may be used, for example, as a positioning device for measurement. This ultrasonic driving device includes a driving force transmitting member fixed to the movable body and abutting on a pressing member of the ultrasonic motor. The driving force transmitting member is frictionally driven by the pressing member. The movable body integrated with the member is driven.
[0005]
As a conventional example of such an ultrasonic drive device, there is one described in, for example, JP-A-11-136968. In this ultrasonic driving device, the contact surfaces of the pressing member and the movable body that come into contact with each other are formed of dense ceramics or cermet, and at least one of both contact surfaces is made of hard carbon. A wear layer is provided.
[0006]
[Patent Document 1]
JP-A-2-94486
[Patent Document 2]
JP-A-7-273384
[Patent Document 3]
JP-A-2002-27768
[Patent Document 4]
JP-A-11-136968
[0007]
[Problems to be solved by the invention]
However, when the ultrasonic motor is driven, a large impact force is applied between the pressing member that vibrates at a high speed and the partner member with which the pressing member is in contact. When the pressing member is made of a polyimide resin like an ultrasonic motor, there is a problem that the pressing member is easily worn. There is also a problem that the polyimide resin may be softened by frictional heat and adhere to a mating member.
[0008]
In the ultrasonic motor described in JP-A-7-273384, the pressing member is formed of a glass material such as quartz glass or soda glass. However, since the glass material has a small fracture toughness, cracks may occur. There was a problem that chipping and cracking were likely to occur. Therefore, when trying to drive a movable body having a large mass using such an ultrasonic motor, there is a risk that the driving of the movable body may be stopped due to chipping or cracking of the pressing member due to stress generated by frictional driving. Was.
[0009]
Further, although a pressing member formed of alumina, zirconia, or ceramics containing silicon carbide as a main component is less likely to be broken than a glass material, silicon carbide has a self-lubricating property and a coefficient of friction with a mating member. Therefore, when the ultrasonic motor is vibrated at a high speed, there is a problem that a slip occurs between the pressing member and the counterpart member, and it is difficult to drive the movable body at a high speed. In addition, when a load is applied, a pressing member formed of silicon carbide has cracks as a starting point based on pores generated during sintering, and wear is advanced, and a preload between a pressing member and a mating member is increased. However, there is a problem in that a defect occurs in the accuracy of the detachment load.
[0010]
Furthermore, the ultrasonic motor described in Japanese Patent Application Laid-Open No. 2002-27768 has a high Vickers hardness of the pressing member, so that the ultrasonic motor has excellent wear resistance of itself. There was a problem that becomes large. Then, a scratch is generated on the mating member due to the abrasion powder, or both are shaved by the abrasion powder caught between the pressing member and the mating member, thereby causing abrasion.
[0011]
In addition, if abrasion powder gets caught between the pressing member and the mating member, the state of contact between the two changes, which may adversely affect the operation and positioning accuracy of the movable body, and the cracks generated on the pressing member may propagate. As a result, the life of the ultrasonic motor may be shortened.
Also, as the Vickers hardness of ceramics increases, the fracture toughness tends to decrease. Therefore, when a large impact force is applied between the pressing member vibrating at high speed and the mating member, cracks are generated and propagated in the pressing member. However, there is a problem that the wear of the mating member increases. Then, as described above, the problem of scratches and biting caused by the abrasion powder occurs.
[0012]
Further, under general sliding friction conditions where no impact force is applied to ceramics and cermets, wear tends to be suppressed if the Vickers hardness is high. However, in the ultrasonic driving device, a vertical impact force is applied between the pressing member and the movable body (the counterpart member) at the time of operation. Therefore, even when the Vickers hardness of the movable body is high, the resistance to bending (bending strength). , The following problems may occur. That is, when the bending strength of the movable body is low, the thickness is thin, or when the size of fine cracks generated on the surface during processing or finishing exceeds a predetermined value, the movable body is near the surface or near the surface. Cracks are generated and propagated, and wear of the movable body is significantly increased. Then, the abrasion powder causes scratches on the movable body, and the abrasion powder caught between the pressing member and the movable body scrapes both of them to cause abrasion.
[0013]
On the other hand, in the ultrasonic driving device including the ultrasonic motor as described above, there is a possibility that the contact surface between the pressing member and the driving force transmitting member is worn and the contact pressure is changed. Then, it becomes difficult to perform high-precision positioning in the positioning device using the ultrasonic driving device. Further, when abrasion powder is generated due to the abrasion, there is a problem that a wafer is adversely affected in a semiconductor manufacturing apparatus using an ultrasonic driving device.
[0014]
Further, in general, hard and brittle materials such as ceramics often have fine cracks on the surface during processing and finishing. However, when the ultrasonic driving device is operated, there is a gap between the pressing member and the driving force transmitting member. Since an impact force is applied, when the pressing member and the driving force transmitting member are made of ceramics, cracks may propagate on the surface or near the surface, and the amount of wear may increase significantly.
[0015]
In addition, the length of the fine crack generated at the time of the above-described processing and finishing is larger than the arithmetic average roughness (Ra) disclosed in Japanese Patent Application Laid-Open No. 2002-027768._max) Is known to be highly correlated. Therefore, in order to reduce the amount of wear of the pressing member and the driving force transmitting member of the ultrasonic driving device, the maximum surface roughness (R_max) Is effective.
[0016]
Therefore, even if the contact surfaces of the pressing member and the movable body are formed of dense ceramics or cermet as in the ultrasonic driving device described in JP-A-11-136968, the bending strength of the movable body is still low. If the thickness is low, the thickness is thin, or the size of fine cracks generated on the surface during processing or finishing exceeds a predetermined value, there is a possibility that abrasion may progress abnormally.
Therefore, the present invention solves the above-mentioned problems of the prior art, and provides an ultrasonic drive device and a guide device that can be used stably for a long period of time even under a high-speed condition or a high-load condition. The task is to provide.
[0017]
[Means for Solving the Problems]
In order to solve the above problem, the present invention has the following configuration. That is, the ultrasonic driving device according to claim 1 of the present invention is an ultrasonic driving device that drives a movable body using vibration in an ultrasonic region, wherein the vibrating body that generates the vibration and the vibration of the vibrating body are provided. An ultrasonic motor having a pressing member that transmits a force to the movable body; and the pressing member is pressed and fixed to the movable body, and is integrated with the movable body by the vibration transmitted through the pressing member. And a contact surface of the driving member that contacts the pressing member and a contact surface of the driving member that contacts the pressing member are formed of ceramics. And the hardness H of the contact surface of the pressing member.₁And the hardness H of the contact surface of the driving force transmitting member₂Ratio H₁/ H₂Is set to 0.75 to 1.5.
[0018]
Here, the hardness of the ceramic (Vickers hardness) is a value measured on a flat surface by JISR1610.
Since the contact surface of the pressing member and the contact surface of the driving force transmitting member are made of ceramics, both are excellent in wear resistance and hardly cause adhesion. Further, it is excellent in heat resistance, corrosion resistance, and rigidity.
[0019]
Furthermore, the hardness H of the contact surface of the pressing member₁And the hardness H of the contact surface of the driving force transmitting member₂Ratio H₁/ H₂Is set to 0.75 to 1.5, so that abrasive wear, which is a main factor of wear, can be effectively suppressed even under lubricating conditions such as non-lubricating conditions and solid contact conditions. Therefore, further increase in wear due to biting of the wear powder and contamination of the external environment due to the wear powder are suppressed, and the ultrasonic drive device can operate stably for a long period of time even under the lubrication conditions described above. it can.
[0020]
The ratio H₁/ H₂Is less than 0.75 or more than 1.5, the hardness H of the contact surface of the pressing member₁And the hardness H of the contact surface of the driving force transmitting member₂Is too large, the higher hardness member causes abrasive wear on the lower member. As a result, the ultrasonic driving device may have a short life or pollute the external environment.
[0021]
An ultrasonic driving apparatus according to claim 2 of the present invention is an ultrasonic driving apparatus that drives a movable body using vibration in an ultrasonic region, wherein the vibration body that generates the vibration and the vibration of the vibration body An ultrasonic motor having a pressing member that transmits a force to the movable body; and the pressing member is pressed and fixed to the movable body, and is integrated with the movable body by the vibration transmitted through the pressing member. A driving force transmitting member driven by the driving force transmitting member, and any one of a contact surface of the pressing member that contacts the driving force transmitting member and a contact surface of the driving force transmitting member that contacts the pressing member. Are made of ceramics, the other is made of cermet or cemented carbide, and the hardness H of the contact surface of the pressing member is₁And the hardness H of the contact surface of the driving force transmitting member₂Ratio H₁/ H₂Is set to 0.75 to 2.1.
[0022]
Here, the hardness (Vickers hardness) of ceramics, cermets, and cemented carbides is measured on a flat surface according to JIS R1610.
Since the contact surface of the pressing member and the contact surface of the driving force transmission member are made of ceramics, cermet, or cemented carbide, they are both excellent in wear resistance and hardly cause adhesion. Further, it is excellent in heat resistance, corrosion resistance, and rigidity.
[0023]
Furthermore, the hardness H of the contact surface of the pressing member₁And the hardness H of the contact surface of the driving force transmitting member₂Ratio H₁/ H₂Is set to 0.75 to 2.1, so that abrasive wear, which is a main factor of wear, is effectively suppressed even under lubricating conditions such as non-lubricating conditions or other conditions where solid contact occurs. Therefore, further increase in wear due to biting of the wear powder and contamination of the external environment due to the wear powder are suppressed, and the ultrasonic drive device can operate stably for a long period of time even under the lubrication conditions described above. it can.
[0024]
The ratio H₁/ H₂Is less than 0.75 or more than 2.1, the hardness H of the contact surface of the pressing member is₁And the hardness H of the contact surface of the driving force transmitting member₂Is too large, the higher hardness member causes abrasive wear on the lower member. As a result, the ultrasonic driving device may have a short life or pollute the external environment.
Furthermore, an ultrasonic driving device according to a third aspect of the present invention is the ultrasonic driving device according to the first or second aspect, wherein the thermal conductivity of the ceramic is 45 W / m · K or more. And
[0025]
If high thermal conductive ceramic is used for the pressing member and the driving force transmitting member, the heat generated at the contact portion between the pressing member and the driving force transmitting member is effectively transmitted and released to the outside. The temperature rise of the contact portion or the whole of the contact member with the driving force transmitting member is effectively suppressed. As a result, excessive increase in contact pressure due to thermal expansion of the pressing member and the driving force transmission member and wear of the contact portion between the pressing member and the driving force transmission member are effectively suppressed. The service life is extended, and when the ultrasonic drive device is applied to the guide device, the positioning accuracy of the guide device is maintained in a high accuracy state for a long period of time.
[0026]
Further, an ultrasonic driving device according to claim 4 of the present invention is an ultrasonic driving device that drives a movable body using vibration in an ultrasonic region, wherein the vibration body that generates the vibration and the vibration of the vibration body An ultrasonic motor having a pressing member that transmits a force to the movable body; and the pressing member is pressed and fixed to the movable body, and is integrated with the movable body by the vibration transmitted through the pressing member. And a contact surface of the pressing member that contacts the driving force transmitting member and a contact surface of the driving force transmitting member that contacts the pressing member. , Cermet, or cemented carbide, and the material forming the contact surfaces is a fracture toughness value K._IC/ (Vickers hardness Hv x maximum surface roughness R_max ^0.5) ≧ 0.003.
[0027]
Here, the fracture toughness value K of ceramics, cermet, and cemented carbide is_IC(Unit is MPa ・ m^1/2) Is measured by the IF method (Indentation Fracture method) of JIS R1607 on the flat surface, and the Vickers hardness Hv (unit: GPa) is measured on the flat surface by JIS R1610. Things.
Since the contact surface of the pressing member and the contact surface of the driving force transmission member are made of ceramics, cermet, or cemented carbide, they are both excellent in wear resistance and hardly cause adhesion. Further, it is excellent in heat resistance, corrosion resistance, and rigidity.
[0028]
Further, the material forming the two contact surfaces has a fracture toughness value K_IC/ (Vickers hardness Hv x maximum surface roughness R_max ^0.5) ≥ 0.003, and therefore, even under non-lubricated or low-viscosity lubricating oils and other lubricating conditions in which solid contact occurs, abrasive wear, which is the main factor of wear, occurs. Is effectively suppressed. Therefore, further increase in wear due to biting of the wear powder and contamination of the external environment due to the wear powder are suppressed, and the ultrasonic drive device can operate stably for a long period of time even under the lubrication conditions described above. it can.
[0029]
The two contact surfaces have a fracture toughness value K_ICAnd a maximum surface roughness R_maxIs processed or finished so as to reduce (ie, cracks generated on the surface are small), so that even if an impact force is applied to both of the contact surfaces, the surface of the pressing member or the driving force transmitting member or Cracks hardly propagate near the surface, and wear is effectively suppressed. Therefore, even under the above-described lubrication condition, the ultrasonic driving device can be operated stably for a long period of time.
[0030]
The material constituting the two contact surfaces has a fracture toughness value K_IC/ (Vickers hardness Hv x maximum surface roughness R_max ^0.5If the expression of ≧ 0.003 is not satisfied, when an impact force is applied to the two contact surfaces, cracks propagate to the surface of the pressing member or the driving force transmitting member or to the vicinity of the surface, and wear is extremely large. Become. As a result, the ultrasonic driving device may have a short life or pollute the external environment.
[0031]
Further, an ultrasonic driving device according to claim 5 of the present invention is an ultrasonic driving device that drives a movable body using vibration in an ultrasonic region, wherein the vibration body that generates the vibration and the vibration of the vibration body An ultrasonic motor having a pressing member that transmits a force to the movable body; and the pressing member is pressed and fixed to the movable body, and is integrated with the movable body by the vibration transmitted through the pressing member. And a contact surface of the pressing member contacting the driving force transmitting member and the driving force transmitting member are formed of ceramic, cermet, and cemented carbide, respectively. And the driving force transmitting member satisfies the following expression.
[0032]
Bending strength x (Thickness / Maximum surface roughness R_max)²× 10^-6≧ 300 (MPa)
Here, the flexural strength of ceramics, cermet, and cemented carbide is measured according to JIS R1601.
With such a configuration, even if an impact force is applied between the pressing member and the driving force transmission member, cracks are unlikely to propagate on or near the surface of the driving force transmission member, so that wear is less likely to occur. Therefore, the ultrasonic driving device operates stably for a long period of time.
[0033]
If the driving force transmitting member does not satisfy the above formula, when an impact force is applied between the pressing member and the driving force transmitting member, cracks are likely to propagate to the surface or near the surface of the driving force transmitting member, Wear increases significantly. Then, the life of the ultrasonic driving device may be shortened, or the external environment may be contaminated by abrasion powder.
Further, since the contact surface of the pressing member and the driving force transmitting member that are in contact with the driving force transmitting member are each made of any one of ceramics, cermet, and cemented carbide, Has excellent abrasion resistance and hardly causes adhesion. Further, it is excellent in heat resistance, corrosion resistance, and rigidity.
[0034]
Further, an ultrasonic driving device according to claim 6 of the present invention is an ultrasonic driving device that drives a movable body using vibrations in an ultrasonic region, wherein the vibration body that generates the vibration and the vibration of the vibration body An ultrasonic motor having a pressing member that transmits a force to the movable body; and the pressing member is pressed and fixed to the movable body, and is integrated with the movable body by the vibration transmitted through the pressing member. And a contact surface of the pressing member contacting the driving force transmitting member, the pore having an equivalent circular diameter of 10 μm or less is formed by 1 mm.²It is characterized by comprising ceramics having 10,000 or less per unit.
[0035]
Further, an ultrasonic driving apparatus according to claim 7 of the present invention is an ultrasonic driving apparatus for driving a movable body using vibration in an ultrasonic region, wherein the vibration body generating the vibration and the vibration of the vibration body are provided. An ultrasonic motor having a pressing member that transmits a force to the movable body; and the pressing member is pressed and fixed to the movable body, and is integrated with the movable body by the vibration transmitted through the pressing member. And a contact surface of the pressing member contacting the driving force transmitting member, the pore having an equivalent circular diameter of 10 μm or less is formed by 1 mm.²1mm pores with 10000 or less per unit and equivalent circle diameter of 30μm or more²It is characterized by being made of ceramics having 50 or less per unit.
[0036]
With such a configuration, abrasive wear, which is a main factor of wear, can be effectively suppressed even under lubricating conditions such as non-lubricating conditions or other conditions where solid contact occurs. Therefore, further increase in wear due to biting of the wear powder and contamination of the external environment due to the wear powder are suppressed, and the ultrasonic drive device can operate stably for a long period of time even under the lubrication conditions described above. it can. Further, there is no possibility that the pressing member is chipped or cracked due to the stress generated by the friction driving, and the driving of the movable body is stopped.
[0037]
The number of pores whose equivalent circular diameter is 10 μm or less is 1 mm²The number of pores exceeding 10000 per one or having an equivalent circular diameter of 30 μm or more is 1 mm²If it exceeds 50 per unit, cracks originating from the pores will be generated, and the cracks will be easily propagated. May occur and the driving of the movable body may stop.
[0038]
In the present invention, the equivalent circular diameter means a diameter D obtained by the following equation from a pore cross-sectional area S obtained by image analysis or the like.
D = √ (4S / π)
Further, an ultrasonic driving device according to claim 8 of the present invention is characterized in that, in the ultrasonic driving device according to any one of claims 1 to 7, the ceramic is alumina that is sintered by pressure.
[0039]
Since alumina sintered under pressure has few defects, abrasive wear, which is a main factor of wear, is effectively suppressed even under the lubricating condition where solid contact occurs as described above. Therefore, further increase in wear due to biting of the wear powder and contamination of the external environment due to the wear powder are suppressed. Further, even if an impact force is applied to the contact surfaces, cracks are unlikely to propagate on or near the surface of the pressing member or the driving force transmitting member, and wear is effectively suppressed. Therefore, even under the above-described lubrication condition, the ultrasonic driving device can be operated stably for a long period of time.
[0040]
Further, the ultrasonic driving device according to claim 9 according to the present invention is the ultrasonic driving device according to any one of claims 1 to 8, wherein the contact surface of the pressing member that contacts the driving force transmitting member and the ultrasonic driving device. At least one of the abutting surfaces of the driving force transmitting member abutting on the pressing member is coated with a lubricating film containing a fluoropolymer having a functional group and a perfluoropolyether oil. .
[0041]
If the contact portion between the pressing member and the driving force transmitting member is covered with a lubricating film, it is unlikely that both will contact without lubrication. Therefore, the abrasion and adhesion are less likely to occur at the contact portion between the two, and the ultrasonic driving device has excellent durability and low dust generation.
Further, since the lubricating film contains a fluoropolymer having a functional group and a perfluoropolyether oil (PFPE oil), it has a certain degree of fluidity. Therefore, even when driven at a relatively high speed or under a high load, unlike a coating film of a conventional solid lubricant or the like, peeling or chipping occurs at a contact portion between the pressing member and the driving force transmission member. It is unlikely to occur. Therefore, such an ultrasonic drive device generates low dust, and can be used without problems even in an environment where particles are a very serious problem, such as a semiconductor manufacturing device.
[0042]
Further, the ultrasonic driving device according to claim 10 of the present invention is the ultrasonic driving device according to any one of claims 1 to 8, wherein the contact surface of the pressing member that contacts the driving force transmitting member and the ultrasonic driving device. At least one of the contact surface of the driving force transmitting member and the pressing member is activated by a halogen-based gas and is coated with a lubricating film.
[0043]
Further, the ultrasonic driving device according to claim 11 of the present invention is the ultrasonic driving device according to any one of claims 1 to 8, wherein the contact surface of the pressing member that contacts the driving force transmitting member and the ultrasonic driving device. At least one of the contact surfaces of the driving force transmitting member that contacts the pressing member is activated by plasma processing and is coated with a lubricating film.
[0044]
Further, an ultrasonic drive device according to claim 12 of the present invention is characterized in that, in the ultrasonic drive device according to claim 10 or 11, the lubricating film contains perfluoropolyether oil.
When the lubricating film is coated on the contact surface activated by performing the above-described treatment, the wettability and the bonding force between the contact surface and the lubricating film (PFPE oil) are improved. The contact surface of the driving force transmitting member is unlikely to be in a state of non-lubricating contact, and a state in which the lubricating film is always interposed at the contact portion is maintained. Therefore, since the adhesion and the abrasion at the contact portion hardly occur, the ultrasonic driving device has excellent durability and low dust generation.
[0045]
Further, since the lubricating film contains PFPE oil, it has a certain degree of fluidity. Therefore, even when driven at a relatively high speed or under a high load, unlike a coating film of a conventional solid lubricant or the like, peeling or chipping occurs at a contact portion between the pressing member and the driving force transmission member. It is unlikely to occur. Therefore, such an ultrasonic drive device generates low dust, and can be used without problems even in an environment where particles are a very serious problem, such as a semiconductor manufacturing device.
[0046]
Further, a guide device according to claim 13 of the present invention is a guide device comprising: a movable body, a support member that supports the movable body, and a drive unit that drives the movable body. 13. An ultrasonic drive device according to any one of 1 to 12,
Since the ultrasonic drive device has the above-described excellent performance, the guide device has excellent durability, and also has excellent operation accuracy and positioning accuracy. In addition, since the frictional force between the pressing member and the driving force transmitting member is moderate, even when the ultrasonic motor is vibrated at a high speed, slippage does not occur between the pressing member and the driving force transmitting member, and the movable body is moved at high speed. Can be driven. Further, since the particles are low in dust generation, they can be used without problems even in an environment where particles are a very serious problem such as a semiconductor manufacturing apparatus.
[0047]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of an ultrasonic drive device and a guide device according to the present invention will be described in detail with reference to the drawings.
First, the ultrasonic motor will be described. FIGS. 1A and 1B are diagrams illustrating the structure of an ultrasonic motor used in an ultrasonic drive device, wherein FIG. 1A is a front view of the ultrasonic motor, and FIG.
The ultrasonic motor 1 is a multi-mode ultrasonic motor, and includes a vibrating body 2 that generates vibration in an ultrasonic region, and a pressing member 3 that transmits the vibration of the vibrating body 2 to a movable body. I have.
[0048]
The vibrating body 2 is composed of a piezoelectric ceramic plate 5 made of lead zirconate titanate, barium titanate, lithium niobate, and the like, and electrode films attached to both plate surfaces. The electrode film attached to one of the plate surfaces is divided into four as shown in FIG. 1A, and the electrode films 6A and 6C, and the electrode films 6B and 6D, which are located on diagonal lines. Are respectively connected. The electrode film 7 attached to the other plate surface covers almost the entire surface as can be seen from FIG. The pressing member 3 is attached to an end surface of the piezoelectric ceramic plate 5.
[0049]
When a voltage having a phase difference of 90 ° is applied to each of the electrode films 6A and 6B and the electrode film 7 is grounded, longitudinal vibration and transverse vibration are generated in the piezoelectric ceramic plate 5, and these two types of vibrations are synthesized. It becomes an elliptical vibration. Then, due to the elliptical vibration, the pressing member 3 performs an elliptical motion in a certain direction. When the phase of the voltage applied to the electrode films 6A and 6B is reversed, the pressing member 3 makes an elliptical motion in the opposite direction.
[0050]
Next, a guide device using an ultrasonic driving device including the above-described ultrasonic motor 1 as a driving means of a movable body will be described in detail with reference to a plan view of FIG.
A pair of guide rails 12 such as a cross roller guide are disposed in parallel on a flat base 11. A stage 13, which is a movable body, is mounted on the guide rails 12, 12, and the stage 13 can be moved linearly while being guided by the guide rails 12, 12. The guide rail 12 corresponds to a support member which is a component of the guide device according to the present invention.
[0051]
A linear scale 21 is attached to one side surface of the stage 13, and a detection head 22 that reads information recorded on the linear scale 21 is provided at a position facing the linear scale 21. The linear scale 21 and the detecting head 22 constitute a position detecting means 23, and the current position of the stage 13 can be measured.
[0052]
Further, on the other side surface of the stage 13, a driving force transmitting member 15 extending over both ends in the longitudinal direction of the stage 13 is fixed, and to the driving force transmitting member 15, the above-described ultrasonic motor 1 fixed on the base 11 is attached. Is pressed. The pressing member 3 is pressed by the driving force transmitting member 15 by the urging force of a spring 32 interposed between the container 31 in which the ultrasonic motor 1 is accommodated and the ultrasonic motor 1. Can be measured. The ultrasonic motor 1 is attached to the container 31 by four springs 34.
[0053]
When the ultrasonic motor 1 is started, the pressing member 3 makes an elliptical motion, so that the driving force transmitting member 15 to which the pressing member 3 is pressed is driven by friction driving. Then, the stage 13 integrated with the driving force transmitting member 15 moves along the guide rail 12.
At this time, since the current position of the stage 13 is detected by the position detecting means 23, the movement of the stage 13 can be controlled based on the obtained current position information. That is, the control device 25 performs an arithmetic process on the basis of a parameter that changes according to a deviation between the reference position information based on the preset movement profile of the stage 13 and the current position information. The changed current is input from the driver 26 to the ultrasonic motor 1.
[0054]
The ultrasonic motor 1 and the driving force transmitting member 15 constitute an ultrasonic driving device. The pressing member 3 and the driving force transmitting member 15 are both made of ceramics, or one of them is made of ceramics. The other is made of cermet or cemented carbide. Therefore, the pressing member 3 and the driving force transmitting member 15 are excellent in wear resistance and are less likely to adhere. Further, it is excellent in heat resistance, corrosion resistance, and rigidity.
[0055]
Further, the hardness H of the contact surface of the pressing member 3 contacting the driving force transmission member 15₁And the hardness H of the contact surface of the driving force transmitting member 15 contacting the pressing member 3₂Ratio H₁/ H₂Is 0.75 to 1.5 when both the pressing member 3 and the driving force transmitting member 15 are made of ceramics, one is made of ceramics and the other is made of cermet or cemented carbide. In this case, it is 0.75 to 2.1.
[0056]
Therefore, even under non-lubricated conditions, etc., wear is small, and further increase in wear due to biting of wear powder and contamination of the external environment due to wear powder are suppressed. The driving device can operate stably for a long period of time. Further, the guide device provided with such an ultrasonic drive device can be stably used for a long period of time even under a high speed condition or a high load condition.
[0057]
Therefore, the ultrasonic drive device and the guide device of the present embodiment can be suitably used for a semiconductor manufacturing device (a transfer device, an exposure device, and the like), a precision processing machine, a precision measurement device, and the like.
Note that the present embodiment is an example of the present invention, and the present invention is not limited to the present embodiment. For example, in the present embodiment, a multi-mode ultrasonic motor is used. The ultrasonic motor of the above can also be used. In the present embodiment, the guide device in which the movable body moves linearly has been described as an example, but the present invention is also applicable to a guide device in which the movable body rotates.
[0058]
Next, in the guide device having the same configuration as described above, various types of materials constituting the pressing member 3 and the driving force transmission member 15 were prepared. Then, each guide device was operated continuously to evaluate its durability.
In the guide devices of Examples 1 to 12 and Comparative Examples 1 to 4, the pressing member 3 and the driving force transmitting member 15 are made of ceramics, cermit, or cemented carbide as shown in Table 1. Then, the hardness H of the material constituting the pressing member 3₁And the hardness H of the material forming the driving force transmitting member 15₂Ratio H₁/ H₂Is a value as shown in Table 1.
[0059]
[Table 1]

[0060]
In the guide devices of the tenth and eleventh embodiments, the surface of the driving force transmission member 15 is coated with a lubricating film as described below. A similar lubricating film is coated on the surface.
The lubricating film was coated as follows. 8% by mass of a fluoropolymer having a functional group (a modified product of Demnum SA manufactured by Daikin Industries, Ltd.) was added to PFPE oil (IS / V manufactured by NOK Cruiba) and mixed. Then, this mixture was diluted to 5% by mass with a fluorine-based solvent (AK225 manufactured by Asahi Chemical Industry Co., Ltd.). This solution was applied to the pressing member 3 and the driving force transmitting member 15 and dried at room temperature, and then heated at 100 to 200 ° C. for 30 minutes in a high-temperature bath or the like to form a lubricating film.
[0061]
The used ceramics, cermets and cemented carbides are as follows.
-Silicon nitride 1: Nippon Tungsten Co., Ltd. NPN-3, Vickers hardness Hv = 1850, fracture toughness value K_IC= 7.5MPa · m^1/2
-Silicon nitride 2: S / RBSN manufactured by SINERAMIC, Vickers hardness Hv = 1100
-Zirconia 1: Z703 manufactured by Kyocera Corporation, Vickers hardness Hv = 1350
[0062]
-Zirconia 2: NPZ-2 manufactured by Nippon Tungsten Co., Vickers hardness Hv = 1450, fracture toughness value K_IC= 7.5MPa · m^1/2
-Zirconia 3: Kyocera Corporation's Z21H0, Vickers hardness Hv = 1100
・ Alumina 1: AJPF manufactured by Nippon Ceratech Co., Ltd., Vickers hardness Hv = 1900, fracture toughness K_IC= 3.5MPa · m^1/2
Alumina 2: A-601D manufactured by Kyocera Corporation, Vickers hardness Hv = 1720, fracture toughness K_IC= 5.7MPa · m^1/2, Bending strength = 400 MPa
[0063]
Alumina 3: Nikkato SSA-999W, Vickers hardness Hv = 2010, fracture toughness K_IC= 3.5MPa · m^1/2, Bending strength = 588 MPa
Alumina 4: A96 manufactured by Shinagawa White Brick Co., Ltd., Vickers hardness Hv = 1320
Alumina 5: SA812, manufactured by Sodick New Materials Co., Ltd., Vickers hardness Hv = 1600, fracture toughness K_IC= 3.2MPa · m^1/2, Bending strength = 390 MPa
[0064]
-Silicon carbide: SC20 manufactured by NGK Insulators, Ltd., Vickers hardness Hv = 28.6 GPa, fracture toughness value K_IC= 2.5MPa · m^1/2, Bending strength = 580 MPa
Cemented carbide 1: M61U (WC-Ni-Cr type) manufactured by Sumitomo Electric Industries, Ltd., Vickers hardness Hv = 1250, fracture toughness K_IC= 9MPa · m^1/2
Cemented carbide 2: RCCL (WC-TiC-TaC system) manufactured by Nippon Tungsten Co., Ltd., Vickers hardness Hv = 2000, fracture toughness K_IC= 6.5MPa · m^1/2, Bending strength = 1000 MPa
[0065]
Cemented carbide 3: FB01 (WC-Co-Ni system) manufactured by Daijet Industries, Vickers hardness Hv = 2800, fracture toughness K_IC= 5.5MPa · m^1/2
Cermet 1: DUX40 (TiC-TaN-Ni-Mo system) manufactured by Nippon Tungsten Co., Vickers hardness Hv = 1450, fracture toughness K_IC= 7MPa · m^1/2, Bending strength = 1600 MPa
Cermet 2: UD-II35T (boride type) manufactured by Asahi Glass Co., Ltd., Vickers hardness Hv = 1000, fracture toughness K_IC= 17MPa · m^1/2
[0066]
Next, a method for evaluating the durability of the guide device will be described. The stage 13 is driven by the ultrasonic driving device, and the durability of the guide device is determined by the time until the generated abrasion powder is caught between the pressing member 3 and the driving force transmitting member 15 and the stage 13 becomes immovable. evaluated.
Other conditions are as follows. The material of the piezoelectric ceramic plate 5 is a lead zirconate titanate-based ceramic having dimensions of 7.5 mm in width, 30 mm in length and 3 mm in thickness. The pressing member 3 has a cylindrical shape having a diameter of 3.0 mm and a length of 4.0 mm, and a contact surface that contacts the driving force transmitting member 15 is a spherical surface having a radius of curvature of 7.5 mm. Maximum surface roughness R of this contact surface_maxIs 1.5 μm, and the maximum surface roughness R of the driving force transmitting member 15 is_maxIs 2.0 μm.
[0067]
Further, the guide rail 12 is a cross roller guide having a stroke of 100 mm, and the mass of the stage 13 is 3.5 kg. Further, the movement profile of the stage 13 set in advance is trapezoidal control in which the movement distance is set to 50 mm, the acceleration / deceleration is set to 0.05 G, and the maximum speed is set to 100 mm / s. Further, the driving frequency of the ultrasonic motor 1 was set to 40 kHz.
[0068]
Table 1 also shows the evaluation results of the durability. In addition, the numerical values of the durability in Table 1 are shown as relative values when the durability of Comparative Example 1 is set to 1.
As can be seen from Table 1, the guide devices of the first to twelfth examples have the same structure as that of the case where the materials forming the pressing member 3 and the driving force transmitting member 15 are both ceramics.₁/ H₂Is 0.75 to 1.5, and when one of the materials forming the pressing member 3 and the driving force transmitting member 15 is ceramics and the other is cermet or cemented carbide, .1, the above H₁/ H₂Was significantly superior to those of Comparative Examples 1 to 4 in which the value was out of the above range.
[0069]
The H₁/ H₂Is shown in the graph of FIG. In the graph, the mark “印” indicates that the material forming the pressing member 3 and the driving force transmitting member 15 are both ceramics, and the mark □ indicates the material forming the pressing member 3 and the driving force transmitting member 15. Shows a case where one of them is ceramic and the other is cermet or cemented carbide. The durability values in this graph are relative values when the durability of Comparative Example 1 is set to 1.
[0070]
From this graph, it can be seen from the graph that when the materials forming the pressing member 3 and the driving force transmitting member 15 are both ceramics, H₁/ H₂It can be understood that when the value is 0.75 to 1.5, the durability of the guide device is excellent. When one of the materials forming the pressing member 3 and the driving force transmitting member 15 is ceramics and the other is cermet or cemented carbide, H₁/ H₂Is 0.75 to 2.1, the guide device has excellent durability.
[0071]
Next, a guide device having the same configuration as that described above was prepared by changing the types of materials constituting the pressing member 3 and the driving force transmitting member 15 as shown in Table 2. That is, in the guide devices of Examples 13 to 20 and Comparative Examples 5 to 7, the pressing member 3 and the driving force transmitting member 15 are each made of any one of ceramics, cermet, and cemented carbide. The material constituting both members 3 and 15 has a fracture toughness value K_IC/ (Vickers hardness Hv x maximum surface roughness R_max ^0.5) Are as shown in Table 2. This value is the maximum surface roughness R during processing and finishing._maxAre adjusted to various values. Note that the guide devices described in Table 2 do not include the lubricating film as described above.
[0072]
[Table 2]

[0073]
Then, these guide devices were operated continuously to evaluate their durability. Hereinafter, a method for evaluating the durability of the guide device will be described. The stage 13 is driven by the ultrasonic driving device, and the durability of the guide device is determined by the time until the generated abrasion powder is caught between the pressing member 3 and the driving force transmitting member 15 and the stage 13 becomes immovable. evaluated.
[0074]
Other conditions are as follows. The material of the piezoelectric ceramic plate 5 is a lead zirconate titanate-based ceramic having dimensions of 7.5 mm in width, 30 mm in length and 3 mm in thickness. The pressing member 3 has a cylindrical shape having a diameter of 3.0 mm and a length of 4.0 mm, and a contact surface that contacts the driving force transmitting member 15 is a spherical surface having a radius of curvature of 6.5 mm.
[0075]
Further, the guide rail 12 is a cross roller guide having a stroke of 100 mm, and the mass of the stage 13 is 3.5 kg. Further, the preset movement profile of the stage 13 was trapezoidal control in which the movement distance was set at 50 mm, the acceleration / deceleration was set at 0.04 G, and the maximum speed was set at 100 mm / s. Further, the driving frequency of the ultrasonic motor 1 was set to 40 kHz.
[0076]
Table 2 also shows the evaluation results of the durability. The durability values in Table 2 are shown as relative values when the durability of Comparative Example 5 is set to 1.
As can be seen from Table 2, the guide devices of Examples 13 to 20 have the fracture toughness value K of the material forming the pressing member 3 and the driving force transmitting member 15._IC/ (Vickers hardness Hv x maximum surface roughness R_max ^0.5) Is 0.003 or more, so that the durability was remarkably superior to Comparative Examples 5 to 7 in which the value was less than 0.003.
[0077]
FIG. 4 is a graph showing the correlation between the value of the material forming the pressing member 3 and the durability of the guide device. The driving force transmitting member 15 is made of alumina 1, and the above value is 0.0035. The durability values in this graph are shown as relative values when the durability of Comparative Example 5 is set to 1.
From this graph, it can be seen that when the value of the material forming the pressing member 3 is 0.003 or more, the durability of the guide device is excellent.
[0078]
Next, a guide device having the same configuration as described above was prepared by changing the types of materials constituting the plate-shaped driving force transmitting member 15 as shown in Table 3. That is, in the guide devices of Examples 21 to 28 and Comparative Examples 8 to 11, the pressing member 3 is made of the above-described alumina 3, and the driving force transmitting member 15 is made of any one of ceramics, cermet, and cemented carbide. It is made of material. The material constituting the driving force transmitting member 15 is bending strength × (plate thickness / maximum surface roughness R_max)²× 10^-6(Hereinafter referred to as “expression values”) are values as shown in Table 3. This formula value is determined by the type of material constituting the driving force transmitting member 15, the plate thickness of the driving force transmitting member 15, or the maximum surface roughness R adjusted during processing or finishing._maxAre set to various values. Note that the guide devices described in Table 3 do not have the lubricating film as described above.
[0079]
[Table 3]

[0080]
The ceramics, cermet, and cemented carbide used are the materials described above or the materials described below.
・ Alumina 1B: AHPF manufactured by Japan Ceratech Co., Ltd., flexural strength = 700 MPa
・ Silicon nitride 3: Hitachi Metals, Ltd., flexural strength = 750 MPa
-Sialon 1: HCN-40 manufactured by Hitachi Metals, Ltd., bending strength = 830 MPa
Then, these guide devices were operated continuously to evaluate their durability. Hereinafter, a method for evaluating the durability of the guide device will be described.
[0081]
The stage 13 is driven by the ultrasonic driving device, and the durability of the guide device is determined by the time until the generated abrasion powder is caught between the pressing member 3 and the driving force transmitting member 15 and the stage 13 becomes immovable. evaluated.
Other conditions are as follows. The material of the piezoelectric ceramic plate 5 is a lead zirconate titanate-based ceramic having dimensions of 7.5 mm in width, 30 mm in length and 3 mm in thickness. The pressing member 3 is made of the above-mentioned alumina 3 and has a cylindrical shape having a diameter of 3.0 mm and a length of 4.0 mm, and a contact surface which comes into contact with the driving force transmitting member 15 is a spherical surface having a radius of curvature of 7.0 mm. is there. The arithmetic mean surface roughness Ra of the contact surface is 0.1 μm.
[0082]
Further, the guide rail 12 is a cross roller guide having a stroke of 200 mm, and the mass of the stage 13 is 3.5 kg. Further, the movement profile of the stage 13 set in advance is trapezoidal control in which the movement distance is set to 100 mm and the maximum speed is set to 100 mm / s. Further, the driving frequency of the ultrasonic motor 1 was set to 40 kHz.
[0083]
Table 3 also shows the evaluation results of the durability. The durability values in Table 3 are shown as relative values when the durability of Comparative Example 8 is set to 1. As can be seen from Table 3, the guide devices of Examples 21 to 28 were much more durable than Comparative Examples 8 to 11.
The correlation between the above equation value and the durability of the guide device is shown in the graph of FIG. Note that the durability values in this graph are shown as relative values when the durability of Comparative Example 8 is set to 1. From this graph, it can be seen that when the above formula value is 300 MPa or more, the durability of the guide device is excellent.
[0084]
Next, in the guide device having the same configuration as described above, various types of materials constituting the pressing member 3 and the driving force transmitting member 15 as shown in Table 4 were prepared. That is, the guide devices of Examples 30 and 31 are configured such that the pressing member 3 is formed of ceramics (alumina) sintered by pressure, and the guide device of Example 32 is configured of the ceramics whose pressing member 3 is sintered under normal pressure. (Alumina). In the guide devices of Examples 29 and 33, the pressing member 3 and the driving force transmitting member 15 are made of ceramics (alumina) sintered under normal pressure. The hardness H of the material forming the pressing member 3₁And the hardness H of the material forming the driving force transmitting member 15₂Ratio H₁/ H₂Is a value as shown in Table 4.
[0085]
[Table 4]

[0086]
The ceramics described in Table 4 are as follows.
・ Alumina 6: NPA-2 manufactured by Nippon Tungsten Co., Ltd., Vickers hardness Hv = 2000
Alumina 7: Sintered product under pressure (alumina content = 99.5%), Vickers hardness Hv = 1900, average crystal grain size = 5 μm
Alumina 8: Sintered product under pressure (alumina content = 99.9%), Vickers hardness Hv = 2010, average crystal grain size = 0.5 μm
Alumina 9: normal pressure sintered product (alumina content = 95%), Vickers hardness Hv = 1500, average crystal grain size = 45 μm
Then, these guide devices were operated continuously to evaluate their durability. The method of evaluating the durability of the guide device is exactly the same as the method of evaluating the guide devices of the above-described first to twelfth embodiments, and a description thereof will not be repeated.
[0087]
Table 4 also shows the evaluation results of the durability. Note that the durability values in Table 4 are shown as relative values when the durability of Comparative Example 1 described above is set to 1. From Table 4, it can be seen that the durability of the guide device is excellent when the pressing member 3 or the driving force transmitting member 15 is made of alumina sintered by pressure. This is considered to be because alumina sintered under pressure has a small crystal grain size and thus has excellent wear resistance.
[0088]
Therefore, a guide device in which the pressing member 3 was made of alumina having various average crystal grain sizes was prepared, and the durability was evaluated in exactly the same manner as the evaluation method of the guide devices of Examples 1 to 12. The driving force transmitting member 15 is made of alumina 6 and has a maximum surface roughness R._maxWas 2.0 μm. Also, the maximum surface roughness R of the pressing member 3_maxWas set to 0.25 μm.
[0089]
The evaluation results are shown in the graph of FIG. Note that the durability values in this graph are relative values when the durability of Comparative Example 1 is set to 1. From the graph, it can be seen that when the average crystal grain size of the sintered alumina is 40 μm or less, the durability of the guide device is excellent. It can be seen that when the average crystal grain size is 20 μm or less, the durability of the guide device is more excellent, and when it is 5 μm or less, it is further excellent. The type of alumina sintered under pressure is not particularly limited.
[0090]
Next, in the guide device having the same configuration as described above, a guide device in which the contact surface of the driving force transmitting member 15 contacting the pressing member 3 was coated with a lubricating film was prepared. That is, the pressing member 3 and the driving force transmitting member 15 are made of materials as shown in Table 4, and the hardness H of the material forming the pressing member 3 is₁And the hardness H of the material forming the driving force transmitting member 15₂Ratio H₁/ H₂Is a value as shown in Table 4. The contact surface of the driving force transmitting member 15 that contacts the pressing member 3 is covered with a lubricating film after the activation process. The contact surface of the pressing member 3 that contacts the driving force transmitting member 15 is not covered with the lubricating film.
[0091]
The lubricating film was coated as follows. First, after the contact surface of the driving force transmission member 15 was degreased and washed, an activation process was performed. The contents of the activation process are as follows. In the case of the guide device of Example 34 in Table 4, after the contact surface was heated to 300 ° C., the NF₃Gas was contacted. In the case of the guide device of Example 35, the contact surface was subjected to plasma processing under atmospheric pressure. In the case of the guide device of Example 36, the contact surface was subjected to argon plasma treatment under reduced pressure. In the case of the guide device of Comparative Example 12, the lubricating film was covered without performing the activation treatment.
[0092]
In Example 34, NF₃The contact surface was activated by a gas, but the type of halogen-based gas used for activation is not particularly limited.₃, CF₄, CCl₄, CBr₄, CI₄, CHF₃, CHCl₃, CHBr₃, CHI₃, SF₆, F₂Etc. can be used.
In addition, the plasma treatment used in Example 35 means that an object to be processed is exposed to plasma to remove organic substances physically or chemically adsorbed on the surface of the object.₂The plasma is actuated and CO, CO₂, H₂This is a method of cleaning the surface of the object by forming O. This method can be performed both under reduced pressure or in air. However, when not only organic matter but also inorganic matter is present as dirt on the surface of the object,₂Plasma cannot be sufficiently removed.
[0093]
In such a case, it is preferable to generate plasma under reduced pressure, accelerate ions in the ion sheath, collide gas ions with dirt, and perform cleaning by physical action. In any of the plasma treatments, air, oxygen, argon, a halogen-based gas, or a mixed gas thereof can be used.
Next, the PFPE oil (Demmnum S-200 manufactured by Daikin Industries, Ltd.) diluted with a fluorine-based solvent (AK225 manufactured by Asahi Chemical Industry Co., Ltd.) to 2% by mass was brought into contact with the activated driving force transmitting member 15. Coated on the surface. Then, after drying at room temperature, a lubricating film was formed by heat treatment at 100 to 200 ° C. for 30 minutes to 1 hour in a high-temperature bath or the like. In each of the examples and comparative examples, the thickness of the lubricating film was 0.7 μm.
[0094]
The thickness of the lubricating film can be controlled by the concentration of the PFPE oil dissolved in the fluorine-based solvent. Further, the thickness can be verified by an infrared spectrometer using a calibration curve prepared in advance. The method for coating the lubricating film is not particularly limited.
Then, these guide devices were operated continuously to evaluate their durability. The method of evaluating the durability of the guide device is exactly the same as the method of evaluating the guide devices of the above-described first to twelfth embodiments, and a description thereof will not be repeated.
[0095]
Table 4 shows the evaluation results. Note that the durability values in Table 4 are shown as relative values when the durability of Comparative Example 1 described above is set to 1. As can be seen from Table 4, the guide devices of Examples 34 to 36 cover the contact surface of the driving force transmitting member 15 with the lubricating film after performing the activation process, and thus do not perform the activation process. The durability was remarkably superior to the guide device of Comparative Example 12 coated with a lubricating film.
[0096]
Next, a guide device having the same configuration as that described above was prepared by changing the types of materials constituting the pressing member 3 and the driving force transmitting member 15 as shown in Table 5. That is, in the guide devices of Examples 37 to 41 and Comparative Examples 13 and 14, the pressing member 3 and the driving force transmitting member 15 are formed of ceramic or cermet, and the hardness of the material forming the pressing member 3 is H.₁And the hardness H of the material forming the driving force transmitting member 15₂Ratio H₁/ H₂Is a value as shown in Table 5.
[0097]
[Table 5]

[0098]
The ceramics and cermets used are the materials described above or the materials shown below. That is, the silicon nitride 4 is HSN65 manufactured by Hitachi Metals, Ltd., the Vickers hardness Hv is 1500, and the thermal conductivity is 65 W / m · K. Also, silicon nitrides 5 to 8 are Al₂O₃And Y₂O₃Is 10% by mass in total, and is manufactured by sintering at a sintering temperature of 2000 ° C. Then, at the time of production, the thermal conductivity is changed by changing the crystallization rate of the sintering aid component by changing the cooling rate after sintering in the range of 25 to 150 ° C./h. . Table 6 summarizes various physical properties of the silicon nitrides 5 to 8 including the thermal conductivity. Note that the guide devices described in Table 5 do not have the lubricating film as described above.
[0099]
[Table 6]

[0100]
Then, these guide devices were operated continuously to evaluate their durability. The method of evaluating the durability of the guide device is exactly the same as the method of evaluating the guide devices of the above-described first to twelfth embodiments, and a description thereof will not be repeated.
Table 5 also shows the evaluation results of the durability. The numerical values of the durability in Table 5 are shown as relative values when the durability of Comparative Example 1 is set to 1. From Table 5, it can be seen that there is a tendency that the greater the thermal conductivity of the silicon nitride forming the driving force transmitting member 15, the better the durability of the guide device.
[0101]
Therefore, guide devices in which the driving force transmitting member 15 is made of silicon nitride having various thermal conductivities were prepared, and the durability was evaluated in exactly the same manner as the evaluation method of the guide devices of Examples 1 to 12. In any guide device, the pressing member 3 is made of alumina 1 and has a maximum surface roughness R._maxWas set to 0.25 μm. Also, the maximum surface roughness R of the driving force transmitting member 15_maxWas 2.0 μm.
[0102]
The evaluation results are shown in the graph of FIG. Note that the durability values in this graph are relative values when the durability of Comparative Example 1 is set to 1. From the graph, it is understood that the durability of the guide device is excellent when the thermal conductivity of the silicon nitride forming the driving force transmission member 15 is 45 W / m · K or more.
In the case where the pressing member and the driving force transmitting member are formed using ceramics having high thermal conductivity, the fracture toughness value K_ICIs 4MPa · m^1/2It is preferable to make the above. Then, even if a load is repeatedly applied to the pressing member and the driving force transmitting member during the operation of the ultrasonic driving device, cracks and breakage hardly occur, and the ultrasonic driving device can be stably used for a longer period.
[0103]
In order to improve the thermal conductivity of ceramics, it is necessary to optimize factors that hinder the propagation of lattice vibration in the sintered body, that is, grain boundaries, internal defects, crystal structures, and the like.
Among the internal defects, particularly harmful ones are voids remaining inside the sintered body, and when these are present in a large amount, the thermal conductivity of the sintered body is significantly reduced. Therefore, the thermal conductivity can be effectively improved by reducing the porosity. In order to make the thermal conductivity of the ceramic sufficiently high, the porosity is preferably set to 2% by volume or less. In order to reduce the porosity, it is preferable to manufacture the ceramic by a pressure sintering method such as a HIP sintering method and a gas pressure sintering method.
[0104]
Further, as one of the factors for reducing the thermal conductivity of ceramics, a sintering aid phase existing at the crystal grain boundary is considered. In the case of silicon nitride, the sintering aid is generally Al₂O₃, MgO, CeO and other metal oxides and Y₂O₃, Yb₂O₃, La₂O₃Rare earth oxides are used, and are often added with the upper limit of 20% by mass of the entire sintered body. In particular, Al₂O₃-Y₂O₃Series or Al₂O₃-MgO-based ones are often used, and these are present at the grain boundaries of the sintered body in an amorphous state.
[0105]
In general, solids having an amorphous structure have low thermal conductivity because lattice vibration is difficult to propagate and silicon nitride, which has a large amount of sintering aid in an amorphous state at grain boundaries, has low thermal conductivity. Become. Therefore, by increasing the crystallinity of the sintering aid portion, the thermal conductivity in the sintering aid portion can be improved, and silicon nitride having high thermal conductivity can be obtained. In order to increase the crystallinity of the sintering aid, the cooling rate after sintering may be adjusted. In other words, if the cooling rate is high, the atomic arrangement of the sintering aid component cannot be made in time, and the normal temperature phase is formed by inheriting the amorphous state that is in the high temperature state, but if the cooling rate is reduced, the crystallization proceeds. It becomes a normal temperature phase.
[0106]
In order to make the thermal conductivity of the ceramic sufficiently high, it is preferable that the ratio of the crystalline phase in the grain boundary phase contained in the sintered body is 10% by volume or more. At this time, in order to further improve the thermal conductivity, it is preferable to use an oxide selected from lanthanoid series such as La, Ce, Pr, Nd and Ho as a sintering aid component.
[0107]
Next, in the guide device having the same configuration as described above, various types of materials constituting the pressing member 3 as shown in Table 7 were prepared. That is, in the guide devices of Examples 42 to 46 and Comparative Examples 15 to 17, the pressing member 3 is made of alumina manufactured as described later. The alumina constituting the pressing member 3 has a pore diameter of 1 mm or less of 1 mm.²1mm of pores whose number per hit and equivalent circular diameter is 30μm or more²The number of hits is a value as shown in Table 7. The driving force transmitting member 15 is made of alumina (FG-995) manufactured by CoorsTek Ltd.
[0108]
[Table 7]

[0109]
An example of a method for producing alumina constituting the pressing member 3 will be described below. A slurry was prepared by adding sintering aids such as magnesium oxide and yttrium oxide to alumina powder as a main raw material, and further adding a solvent, an organic binder, a plasticizer, and a dispersant. This slurry was formed, fired at 500 to 1500 ° C. in the air as needed, and then sintered at 1700 to 1900 ° C. in a reducing atmosphere from normal pressure to vacuum to obtain an alumina sintered body. Then, the obtained sintered body was subjected to barrel processing, polishing, and the like to adjust the shape, and the surface was finished to have a pore distribution as shown in Table 7. Note that the guide devices described in Table 7 do not include the lubricating film as described above.
[0110]
Then, these guide devices were operated continuously to evaluate their durability. Hereinafter, a method for evaluating the durability of the guide device will be described.
The stage 13 is driven by the ultrasonic driving device, and the durability of the guide device is determined by the time until the generated abrasion powder is caught between the pressing member 3 and the driving force transmitting member 15 and the stage 13 becomes immovable. evaluated.
[0111]
Other conditions are as follows. The material of the piezoelectric ceramic plate 5 is a lead zirconate titanate-based ceramic having dimensions of 7.5 mm in width, 30 mm in length and 3 mm in thickness. The pressing member 3 is made of the above-described alumina sintered body, has a cylindrical shape having a diameter of 3.0 mm and a length of 4.0 mm, and has a spherical surface having a radius of curvature of 10 mm in contact with the driving force transmitting member 15. is there. Maximum surface roughness R of this contact surface_maxIs 1.5 μm, and the maximum surface roughness R of the driving force transmitting member 15 is_maxIs 2.0 μm.
[0112]
Further, the guide rail 12 is a cross roller guide having a stroke of 100 mm, and the mass of the stage 13 is 3.5 kg. Further, the preset movement profile of the stage 13 was trapezoidal control in which the movement distance was set to 60 mm, the acceleration / deceleration was set to 0.05 G, and the maximum speed was set to 110 mm / s. Further, the driving frequency of the ultrasonic motor 1 was set to 40 kHz.
[0113]
Table 7 also shows the evaluation results of the durability. The durability values in Table 7 are shown as relative values when the durability of Comparative Example 15 is set to 1. From Table 7, it can be seen that the guide device of the example is much more durable than the comparative example.
The types of ceramics, cermets, and cemented carbides that can be used in the present invention are not particularly limited.
[0114]
As ceramics, silicon nitride (Si₃N₄), Zirconia (ZrO)₂) System, alumina (Al₂O₃) Type, silicon carbide (SiC) type, aluminum nitride (AlN) type, boron carbide (B₄C), titanium boride (TiB)₂) -Based, boron nitride (BN) -based, titanium carbide (TiC) -based, titanium nitride (TiN) -based, or a ceramic-based composite material obtained by combining two or more of these.
[0115]
A fibrous filler can be added to such ceramics in order to improve fracture toughness, mechanical strength, and the like. The type of the fibrous filler is not particularly limited, and examples thereof include silicon carbide whiskers, silicon nitride whiskers, alumina whiskers, and aluminum nitride whiskers.
Cermet and cemented carbide are carbide powders of nine kinds of metals (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) belonging to groups IVb, Vb and VIb of the periodic table. And an iron-based metal such as iron, cobalt, and nickel.
[0116]
Examples of the cermet include TiC-Ni, TiC-Mo-Ni, and TiC-Mo.₂C-Ni, TiC-Mo₂C-ZrC-Ni, Mo₂C-Ni-based, Ti (C, N) -Mo₂C-Ni-based, TiC-TiN-Mo₂C-Ni-based, TiC-TiN-Mo₂C-TaC-Ni, TiC-TiN-Mo₂C-WC-TaC-Ni system, TiC-WC-Ni system, Ti (C, N) -WC-Ni system, TiC-Mo system, Ti (C, N) -Mo system, boride system (MoB-Ni) System, B₄C / (W, Mo) B₂System).
[0117]
Note that Ti (C, N) -Mo₂C—Ni, Ti (C, N) —WC—Ni, and Ti (C, N) —Mo are TiC—Mo, respectively.₂C-Ni, TiC-WC-Ni and TiC-Mo are sintered in nitrogen gas.
As the cemented carbide, for example, WC-Ni, WC-Cr₃C₂-Mo₂C-Ni, WC-Ti (C, N) -TaC, WC-Ti (C, N), Cr₃C₂-Ni-based and the like.
[0118]
Further, the type of the fluoropolymer having a functional group that can be used in the present invention is not particularly limited, but a fluoropolyether polymer or a polyfluoroalkyl polymer is preferable.
Examples of the fluoropolyether polymer include a polymer having a repeating unit represented by the following chemical formula (Formula 1) and having a number average molecular weight of 1,000 to 50,000. In addition, this fluoropolyether polymer has a functional group described later on at least one molecular terminal.
[0119]
Embedded image

[0120]
Examples of the polyfluoroalkyl polymer include those represented by the following chemical formula (Formula 2). Y in the formula is a functional group having a high affinity for a metal, and is preferably, for example, an epoxy group, an amino group, a carboxyl group, a hydroxyl group, a mercapto group, an isocyanate group, a sulfone group, an ester group, or the like.
[0121]
Embedded image

[0122]
As the polyfluoroalkyl polymer, for example, those represented by the following chemical formula (Chemical Formulas 3 and 4) can be suitably used in addition to those represented by Chemical Formula 2.
[0123]
Embedded image

[0124]
Embedded image

[0125]
When such a functional group is coated on the surface of the pressing member or the driving force transmission member when the lubricating film is coated on the surface of the pressing member or the driving force transmission member, the functional group bonds to the material constituting the pressing member or the driving force transmission member. A lubricating film that is strongly bonded to the surface is formed. In the case of a fluoropolymer having a plurality of functional groups in one molecule, at least one of them may be bonded to the surface of the pressing member or the driving force transmitting member.
[0126]
The above-mentioned fluorinated polymers may be used alone or in combination of two or more. When two or more kinds are used in combination, a combination of kinds (types of functional groups) of the fluorinated polymer may be selected so that the functional groups react with each other and the fluorinated polymer has a higher molecular weight. preferable. If the fluoropolymer has a higher molecular weight, a lubricating film having more excellent wear resistance can be obtained.
[0127]
Specific examples of the fluorine-containing polymer having such a functional group include, for example, Krytox 157FSL, 157FSM, 157FSH manufactured by DuPont, and denim modified products SA, SH, SY-3, SP manufactured by Daikin Industries, Ltd. And FONBRIN Z DEAL, Z DIAC, Z DISCO, Z DOL, Z DOL TX2000 manufactured by Ausimont Co., Ltd.
[0128]
The type of the PFPE oil is not particularly limited. For example, S-65, S-100, S-200 manufactured by Daikin Industries, Krytox 143AB, 143AC, 143AD manufactured by Dupont, NOK Examples include J400, IEL / V, IMI / V, IS / V manufactured by Kruba, Fomblin Y25, Y45, YR, YLVAC16 / 6, YLVA25 / 6, YHVAC40 / 11, and YHVAC140 / 13 manufactured by Ausimont. Can be
[0129]
The method of forming the lubricating film is not particularly limited, for example, a method of applying or spraying a mixture of a fluoropolymer having a functional group and a PFPE oil on the surface of a pressing member or a driving force transmitting member, And a method of immersing a pressing member or a driving force transmitting member in the mixture.
As an example of a mixture of a fluorinated polymer having a functional group and a PFPE oil, 2 to 15% by mass of the fluorinated polymer having a functional group is added to the PFPE oil, and this is mixed with a fluorinated solvent to form a 1 to 15% by mass. Those diluted to mass% are suitable.
[0130]
Next, after the pressing member and the driving force transmitting member coated with the mixture are dried at room temperature, they are placed in a constant temperature bath or the like and subjected to a heat treatment at 100 to 200 ° C. for about 30 minutes to form a lubricating film.
The process of providing such a lubricating film may be repeated several times as necessary, and the lubricating film is finally formed to a thickness of, for example, 0.3 μm or more. This film thickness can also be controlled by the concentration of the fluorine-containing polymer having a functional group and the PFPE oil dissolved in the fluorine-based solvent.
[0131]
By such a method, it is possible to form a lubricating film with a suitable thickness on the surface of the pressing member or the driving force transmitting member.
In addition, if the solvent is removed by the heat treatment as described above, unnecessary dust is not generated when the ultrasonic driving device is operated. In particular, dust generation and outgassing in the use environment can be suppressed by the final heat treatment.
[0132]
A fluorine-containing polymer having a functional group diluted with a fluorine-based solvent is coated first, heated in a constant temperature bath or the like, and the metal as the base material of the pressing member or the driving force transmitting member is coated with the fluorine-containing polymer. By reacting the functional groups of the coalesced, a layer of a fluoropolymer having a functional group bonded to a metal is formed, and then a PFPE oil diluted with a fluorine-based solvent is coated to cover the functional groups. The lubricating film may have a two-layer structure by forming a PFPE oil layer on the fluorine-containing polymer layer.
[0133]
【The invention's effect】
As described above, the ultrasonic drive device and the guide device of the present invention can be stably used for a long period of time even under a high-speed condition or a high-load condition.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the structure of an ultrasonic motor used in an ultrasonic drive device according to the present invention.
FIG. 2 is a plan view showing an embodiment of a guide device according to the present invention.
FIG. 3 shows the hardness H of the material constituting the pressing member.₁And the hardness H of the material constituting the driving force transmitting member₂Ratio H₁/ H₂6 is a graph showing a correlation between the information and the durability of the guide device.
FIG. 4 is a fracture toughness value K of a material constituting a pressing member._IC/ (Vickers hardness Hv x maximum surface roughness R_max ^0.54 is a graph showing a correlation between the value of ()) and the durability of the guide device.
FIG. 5: bending strength of driving force transmitting member × (plate thickness / maximum surface roughness R)_max)²× 10^-66 is a graph showing a correlation between the value of 案 内 and the durability of the guide device.
FIG. 6 is a graph showing the correlation between the average crystal grain size of alumina and the durability of the guide device.
FIG. 7 is a graph showing a correlation between the thermal conductivity of silicon nitride and the durability of the guide device.
[Explanation of symbols]
1 Ultrasonic motor
2 vibrator
3 Pressing member
12 guide rail
13 stages
15 Driving force transmission member

Claims (13)

An ultrasonic driving device that drives a movable body using vibration in an ultrasonic region,
An ultrasonic motor having a vibrating body that generates the vibration and a pressing member that transmits vibration of the vibrating body to the movable body,
A driving force transmitting member, wherein the pressing member is pressed and fixed to the movable body, and is driven integrally with the movable body by the vibration transmitted through the pressing member;
With
The contact surface of the pressing member that contacts the driving force transmitting member and the contact surface of the driving force transmitting member that contacts the pressing member are made of ceramics, and the hardness H ₁ of the contact surface of the pressing member is set to _1. the contact surface of the ratio _H 1 / of _{H 2} hardness of _{H 2} the driving force transmitting member, ultrasound driving apparatus being characterized in that a 0.75 to 1.5. An ultrasonic driving device that drives a movable body using vibration in an ultrasonic region,
An ultrasonic motor having a vibrating body that generates the vibration and a pressing member that transmits vibration of the vibrating body to the movable body,
A driving force transmitting member, wherein the pressing member is pressed and fixed to the movable body, and is driven integrally with the movable body by the vibration transmitted through the pressing member;
With
Either the contact surface of the pressing member that contacts the driving force transmitting member or the contact surface of the driving force transmitting member that contacts the pressing member is made of ceramics, and the other is made of cermet or cemented carbide. configured, to enable any person hardness of contact surface _{H 1} and the ratio _H 1 / of _{H 2} hardness of _{H 2} abutting surface of the driving force transmitting member of the pressing member, and a 0.75 to 2.1 Ultrasonic drive device characterized by the following. The ultrasonic drive device according to claim 1 or 2, wherein the ceramic has a thermal conductivity of 45 W / m · K or more. An ultrasonic driving device that drives a movable body using vibration in an ultrasonic region,
An ultrasonic motor having a vibrating body that generates the vibration and a pressing member that transmits vibration of the vibrating body to the movable body,
A driving force transmitting member, wherein the pressing member is pressed and fixed to the movable body, and is driven integrally with the movable body by the vibration transmitted through the pressing member;
With
The contact surface of the pressing member abutting on the driving force transmitting member and the contact surface of the driving force transmitting member abutting on the pressing member may be made of any one of ceramic, cermet, and cemented carbide. And the material forming the contact surfaces satisfies the following formula: fracture toughness value K _IC / (Vickers hardness Hv × maximum surface roughness R _max ^0.5 ) ≧ 0.003. Ultrasonic drive device. An ultrasonic driving device that drives a movable body using vibration in an ultrasonic region,
An ultrasonic motor having a vibrating body that generates the vibration and a pressing member that transmits vibration of the vibrating body to the movable body,
A plate-like driving force transmitting member, wherein the pressing member is pressed and fixed to the movable body, and is driven integrally with the movable body by the vibration transmitted through the pressing member;
With
The contact surface of the pressing member abutting on the driving force transmitting member and the driving force transmitting member are each made of a material selected from the group consisting of ceramics, cermets, and cemented carbides. An ultrasonic drive device wherein the member satisfies the following expression.
Bending strength × (plate thickness / maximum surface roughness R _max ) ² × 10 ⁻⁶ ≧ 300 (MPa) An ultrasonic driving device that drives a movable body using vibration in an ultrasonic region,
An ultrasonic motor having a vibrating body that generates the vibration and a pressing member that transmits vibration of the vibrating body to the movable body,
A driving force transmitting member, wherein the pressing member is pressed and fixed to the movable body, and is driven integrally with the movable body by the vibration transmitted through the pressing member;
With
An ultrasonic drive device, wherein a contact surface of the pressing member that contacts the driving force transmitting member is formed of ceramics having 10,000 or less pores per mm ² having an equivalent circular diameter of 10 μm or less. An ultrasonic driving device that drives a movable body using vibration in an ultrasonic region,
An ultrasonic motor having a vibrating body that generates the vibration and a pressing member that transmits vibration of the vibrating body to the movable body,
A driving force transmitting member, wherein the pressing member is pressed and fixed to the movable body, and is driven integrally with the movable body by the vibration transmitted through the pressing member;
With
The contact surface of the pressing member contacting the driving force transmitting member has 10,000 or less pores per 1 mm ² having an equivalent circular diameter of 10 μm or less and 50 or more pores per 1 mm ² having an equivalent circular diameter of 30 μm or more. An ultrasonic drive device comprising a ceramic having not more than one ceramics. The ultrasonic drive device according to any one of claims 1 to 7, wherein the ceramic is alumina sintered under pressure. At least one of the contact surface of the pressing member that contacts the driving force transmitting member and the contact surface of the driving force transmitting member that contacts the pressing member is a fluoropolymer having a functional group and a perfluoropolyether. The ultrasonic drive device according to any one of claims 1 to 8, wherein the ultrasonic drive device is covered with a lubricating film containing oil. At least one of the contact surface of the pressing member abutting on the driving force transmitting member and the contact surface of the driving force transmitting member abutting on the pressing member is activated by a halogen-based gas. The ultrasonic drive device according to any one of claims 1 to 8, wherein the ultrasonic drive device is coated. At least one of the contact surface of the pressing member that contacts the driving force transmitting member and the contact surface of the driving force transmitting member that contacts the pressing member is activated by plasma processing, and is covered with a lubricating film. The ultrasonic driving device according to any one of claims 1 to 8, wherein The ultrasonic drive device according to claim 10, wherein the lubricating film contains a perfluoropolyether oil. A movable body, a support member that supports the movable body, and a driving unit that drives the movable body, wherein the driving unit is the ultrasonic driving device according to any one of claims 1 to 12. A guiding device, comprising:

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