JP2005061238A - Valve device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a large size actuator is necessary as a countermeasure for friction generated at a sliding contact part of a valve stem and a bearing part and reduction of friction at the sliding contact part is desired in a conventional valve device. <P>SOLUTION: This valve device is provided in an intake air route or the like of an engine. Hard carbon coat is formed on at least one of sliding contact surfaces of the valve stem and the bearing part 6 at a part where the valve stem 5 provided with a valve 4 and the bearing part 6 rotatably retaining the valve stem 5 contact and slide to thereby greatly reduce friction at the sliding contact part and enable drive by a small actuator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４８】
【化２】

【００４９】
これら一般式におけるＰＩＢは、ポリブテニル基を示し、高純度イソブテン又は１−ブテンとイソブテンの混合物をフッ化ホウ素系触媒又は塩化アルミニウム系触媒で重合させて得られる数平均分子量が９００〜３５００、望ましくは１０００〜２０００のポリブテンから得られる。上記数平均分子量が９００未満の場合は清浄性効果が劣り易く、３５００を超える場合は低温流動性に劣り易いため、望ましくない。
【００５０】
また、上記一般式におけるｎは、清浄性に優れる点から１〜５の整数、より望ましくは２〜４の整数であることがよい。さらに、上記ポリブテンは、製造過程の触媒に起因して残留する微量のフッ素分や塩素分を吸着法や充分な水洗等の適切な方法により、５０ｐｐｍ以下、より望ましくは１０ｐｐｍ以下、特に望ましくは１ｐｐｍ以下まで除去してから用いることもよい。
【００５１】
さらに、上記ポリブテニルコハク酸イミドの製造方法としては、特に限定はないが、例えば、上記ポリブテンの塩素化物又は塩素やフッ素が充分除去されたポリブテンと無水マレイン酸とを１００〜２００℃で反応させて得られるポリブテニルコハク酸を、ジエチレントリアミン、トリエチレンテトラミン、テトラエチレンペンタミン、ペンタエチレンヘキサミン等のポリアミンと反応させることにより得ることができる。
【００５２】
一方、上記ポリブテニルコハク酸イミドの誘導体としては、上記一般式（１）又は（２）で表される化合物に、ホウ素化合物や含酸素有機化合物を作用させて、残存するアミノ基及び／又はイミノ基の一部又は全部を中和したり、アミド化した、いわゆるホウ素変性又は酸変性化合物を例示できる。その中でもホウ素含有ポリブテニルコハク酸イミド、特にホウ素含有ビスポリブテニルコハク酸イミドが最も好ましいものとして挙げられる。
【００５３】
上記ホウ素化合物としては、ホウ酸、ホウ酸塩、ホウ酸エステル等が挙げられる。具体的には、上記ホウ酸として、オルトホウ酸、メタホウ酸及びテトラホウ酸などが挙げられる。また、上記ホウ酸塩としては、アンモニウム塩等、具体的には、例えばメタホウ酸アンモニウム、四ホウ酸アンモニウム、五ホウ酸アンモニウム、八ホウ酸アンモニウム等のホウ酸アンモニウムが好適例として挙げられる。また、ホウ酸エステルとしては、ホウ酸と好ましくは炭素数１〜６のアルキルアルコールとのエステル、より具体的には例えば、ホウ酸モノメチル、ホウ酸ジメチル、ホウ酸トリメチル、ホウ酸モノエチル、ホウ酸ジエチル、ホウ酸トリエチル、ホウ酸モノプロピル、ホウ酸ジプロピル、ホウ酸トリププロピル、ホウ酸モノブチル、ホウ酸ジブチル、ホウ酸トリブチル等が好適例として挙げられる。なお、ホウ素含有ポリブテニルコハク酸イミドにおけるホウ素含有量Ｂと窒素含有量Ｎとの質量比「Ｂ／Ｎ」は、通常０．１〜３であり、好ましくは、０．２〜１である。
【００５４】
また、上記含酸素有機化合物としては、具体的には、例えばぎ酸、酢酸、グリコール酸、プロピオン酸、乳酸、酪酸、吉草酸、カプロン酸、エナント酸、カプリル酸、ペラルゴン酸、カプリン酸、ウンデシル酸、ラウリン酸、トリデカン酸、ミリスチン酸、ペンタデカン酸、パルミチン酸、マルガリン酸、ステアリン酸、オレイン酸、ノナデカン酸、エイコサン酸等の炭素数１〜３０のモノカルボン酸や、シュウ酸、フタル酸、トリメリット酸、ピロメリット酸等の炭素数２〜３０のポリカルポン酸並びにこれらの無水物、又はエステル化合物、炭素数２〜６のアルキレンオキサイド、ヒドロキシ（ポリ）オキシアルキレンカーボネート等が挙げられる
【００５５】
なお、本発明のバルブ装置に用いる潤滑油組成物において、ポリブテニルコハク酸イミド及び／又はその誘導体の含有量は、０．１〜１５％が望ましく、より望ましくは１．０〜１２％であることが好ましい。０．１％未満では清浄性効果に乏しくなることがあり、１５％を超えると含有量に見合う清浄性効果が得られにくく、抗乳化性が悪化し易い。
【００５６】
さらにまた、本発明のバルブ装置に用いる潤滑油組成物は、次の一般式（３）で表されるジチオリン酸亜鉛を含有することが好適である。
【００５７】
【化３】

【００５８】
上記式（３）中のＲ^４、Ｒ^５、Ｒ^６及びＲ^７は、それぞれ別個に炭素数１〜２４の炭化水素基を示す。これら炭化水素基としては、炭素数１〜２４の直鎖状又は分枝状のアルキル基、炭素数３〜２４の直鎖状又は分枝状のアルケニル基、炭素数５〜１３のシクロアルキル基又は直鎖状若しくは分枝状のアルキルシクロアルキル基、炭素数６〜１８のアリール基又は直鎖状若しくは分枝状のアルキルアリール基、炭素数７〜１９のアリールアルキル基等のいずれかであることが望ましい。また、アルキル基やアルケニル基は、第１級、第２級及び第３級のいずれであってもよい。
【００５９】
上記Ｒ^４、Ｒ^５、Ｒ^６及びＲ^７としては、具体的には、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、へキシル基、ヘプチル基、オクチル基、ノニル基、デシル基、ウンデシル基、ドデシル基、トリデシル基、テトラデシル基、ペンタデシル基、ヘキサデシル基、ヘプタデシル基、オクタデシル基、ノナデシル基、イコシル基、ヘンイコシル基、ドコシル基、トリコシル基、テトラコシル基等のアルキル基、プロペニル基、イソプロペニル基、ブテニル基、ブタジエニル基、ペンテニル基、ヘキセニル基、ヘプテニル基、オクテニル基、ノネニル基、デセニル基、ウンデセニル基、ドデセニル基、トリデセニル基、テトラデセニル基、ペンタデセニル基、ヘキサデセニル基、ヘプタデセニル基、オレイル基等のオクタデセニル基、ノナデセニル基、イコセニル基、ヘンイコセニル基、ドコセニル基、トリコセニル基、テトラコセニル基等のアルケニル基、シクロペンチル基、シクロへキシル基、シクロヘプチル基等のシクロアルキル基、メチルシクロペンチル基、ジメチルシクロペンチル基、エチルシクロペンチル基、プロピルシクロペンチル基、エチルメチルシクロペンチル基、トリメチルシクロペンチル基、ジエチルシクロペンチル基、エチルジメチルシクロペンチル基、プロピルメチルシクロペンチル基、プロピルエチルシクロペンチル基、ジ−プロピルシクロペンチル基、プロピルエチルメチルシクロペンチル基、メチルシクロへキシル基、ジメチルシクロへキシル基、エチルシクロへキシル基、プロピルシクロへキシル基、エチルメチルシクロへキシル基、トリメチルシクロへキシル基、ジエチルシクロヘキシル基、エチルジメチルシクロヘキシル基、プロピルメチルシクロヘキシル基、プロピルエチルシクロヘキシル基、ジ−プロピルシクロへキシル基、プロピルエチルメチルシクロヘキシル基、メチルシクロヘプチル基、ジメチルシクロヘプチル基、エチルシクロヘプチル基、プロピルシクロヘプチル基、エチルメチルシクロヘプチル基、トリメチルシクロヘプチル基、ジエチルシクロヘプチル基、エチルジメチルシクロヘプチル基、プロピルメチルシクロヘプチル基、プロピルエチルシクロヘプチル基、ジ−プロピルシクロヘプチル基、プロピルエチルメチルシクロヘプチル基等のアルキルシクロアルキル基、フェニル基、ナフチル基等のアリール基、トリル基、キシリル基、エチルフェニル基、プロピルフェニル基、エチルメチルフェニル基、トリメチルフェニル基、ブチルフェニル基、プロピルメチルフェニル基、ジエチルフェニル基、エチルジメチルフェニル基、テトラメチルフェニル基、ペンチルフェニル基、ヘキシルフェニル基、ヘプチルフェニル基、オクチルフェニル基、ノニルフェニル基、デシルフェニル基、ウンデシルフェニル基、ドデシルフェニル基等のアルキルアリール基、ベンジル基、メチルベンジル基、ジメチルベンジル基、フェネチル基、メチルフェネチル基、ジメチルフェネチル基等のアリールアルキル基、等が例示できる。
【００６０】
なお、Ｒ^４、Ｒ^５、Ｒ^６及びＲ^７がとり得る上記炭化水素基には、考えられる全ての直鎖状構造及び分枝状構造をが含まれ、また、アルケニル基の二重結合の位置、アルキル基のシクロアルキル基への結合位置、アルキル基のアリール基への結合位置、及びアリール基のアルキル基への結合位置は任意である。また、上記炭化水素基の中でも、その炭化水素基が、直鎖状又は分柱状の炭素数１〜１８のアルキル基である場合若しくは炭素数６〜１８のアリール基、又は直鎖状若しくは分枝状アルキルアリール基である場合が特に好ましい。
【００６１】
上記ジチオリン酸亜鉛の好適な具体例としては、例えば、ジイソプロピルジチオリン酸亜鉛、ジイソブチルジチオリン酸亜鉛、ジ−ｓｅｃ−ブチルジチオリン酸亜鉛、ジ−ｓｅｃ−ペンチルジチオリン酸亜鉛、ジ−ｎ−ヘキシルジチオリン酸亜鉛、ジ−ｓｅｃ−ヘキシルジチオリン酸亜鉛、ジ−オクチルジチオリン酸亜鉛、ジ−２−エチルヘキシルジチオリン酸亜鉛、ジ−ｎ−デシルジチオリン酸亜鉛、ジ−ｎ−ドデシルジチオリン酸亜鉛、ジイソトリデシルジチオリン酸亜鉛、及びこれらの任意の組合せに係る混合物等が挙げられる。
【００６２】
また、上記ジチオリン酸亜鉛の含有量は、より高い摩擦低減効果を発揮させる観点から、潤滑油組成物全量基準且つリン元素換算量で、０．１％以下であることが好ましく、また０．０６％以下であることがより好ましく、さらにはジチオリン酸亜鉛が含有されないことが特に好ましい。ジチオリン酸亜鉛の含有量がリン元素換算量で０．１％を超えると、ＤＬＣ部材と鉄基部材との摺動面における上記脂肪酸エステル系無灰摩擦調整剤や上記脂肪族アミン系無灰摩擦調整剤の優れた摩擦低減効果が阻害されるおそれがある。
【００６３】
上記ジチオリン酸亜鉛の製造方法としては、従来方法を任意に採用することができ、特に制限されないが、具体的には、例えば、上記Ｒ^４、Ｒ^５、Ｒ^６及びＲ^７に対応する炭化水素基を持つアルコール又はフェノールを五二硫化りんと反応させてジチオリン酸とし、これを酸化亜鉛で中和させることにより合成することができる。なお、上記ジチオリン酸亜鉛の構造は、使用する原料アルコールによって異なることは言うまでもない。
【００６４】
本発明においては、上記一般式（３）に包含される２種以上のジチオリン酸亜鉛を任意の割合で混合して使用することもできる。
【００６５】
上述のように、本発明のバルブ装置において、潤滑油組成物は、硬質炭素薄膜で被覆した摺動接触面、すなわちバルブ軸及び軸受部の少なくとも一方の摺動接触面に用いた場合に、極めて優れた低摩擦特性を示すものであるが、特に内燃機関用潤滑油組成物として必要な性能を高める目的で、金属系清浄剤、酸化防止剤、粘度指数向上剤、他の無灰摩擦調整剤、他の無灰分散剤、磨耗防止剤若しくは極圧剤、防錆剤、非イオン系界面活性剤、抗乳化剤、金属不活性化剤、消泡剤等を単独で又は複数種を組合せて配合し、必要な性能を高めることができる。
【００６６】
上記金属系清浄剤としては、潤滑油用の金属系清浄剤として通常用いられる任意の化合物が使用できる。例えば、アルカリ金属又はアルカリ土類金属のスルホネート、フェネート、サリシレートナフテネート等を単独で又は複数種を組合せて使用できる。ここで、上記アルカリ金属としてはナトリウム（Ｎａ）やカリウム（Ｋ）等、上記アルカリ土類金属としてはカルシウム（Ｃａ）やマグネシウム（Ｍｇ）等が例示できる。また、具体的な好適例としては、Ｃａ又はＭｇのスルフォネート、フェネート及びサリシレートが挙げられる。
【００６７】
なお、これら金属系清浄剤の全塩基価及び添加量は、要求される潤滑油の性能に応じて任意に選択できる。通常、全塩基価は、過塩素酸法で０〜５００ｍｇＫＯＨ／ｇ、望ましくは１５０〜４００ｍｇＫＯＨ／ｇであり、その添加量は潤滑油組成物全量基準で、通常０．１〜１０％である。
【００６８】
また、上記酸化防止剤としては、潤滑油用の酸化防止剤として通常用いられる任意の化合物を使用できる。例えば、４，４’−メチレンビス（２，６−ジ−ｔｅｒｔ−ブチルフェノール）、オクタデシル−３−（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシフェニル）プロピオネート等のフェノール系酸化防止剤、フェニル−α−ナフチルアミン、アルキルフェニル−α−ナフチルアミン、アルキルジフェニルアミン等のアミン系酸化防止剤、並びにこれらの任意の組合せに係る混合物等が挙げられる。また、かかる酸化防止剤の添加量は、潤滑油組成物全量基準で、通常０．０１〜５％である。
【００６９】
さらに、上記粘度指数向上剤としては、具体的には、各種メタクリル酸エステルから選ばれる１種又は２種以上のモノマーの共重合体やその水添物等のいわゆる非分散型粘度指数向上剤、及びさらに窒素化合物を含む各種メタクリル酸エステルを共重合させたいわゆる分散型粘度指数向上剤等が例示できる。また、他の粘度指数向上剤の具体例としては、非分散型又は分散型エチレン−α−オレフィン共重合体（α−オレフィンとしては、例えばプロピレン、１−ブテン、１−ペンテン等）及びその水素化物、ポリイソブチレン及びその水添物、スチレン−ジエン水素化共重合体、スチレン−無水マレイン酸エステル共重合体、並びにポリアルキルスチレン等も例示できる。
【００７０】
これら粘度指数向上剤の分子量は、せん断安定性を考慮して選定することが必要である。具体的には、粘度指数向上剤の数平均分子量は、例えば分散型及び非分散型ポリメタクリレートでは５０００〜１００００００、好ましくは１０００００〜８０００００がよく、ポリイソブチレン又はその水素化物では８００〜５０００、エチレン−α−オレフィン共重合体又はその水素化物では８００〜３０００００、好ましくは１００００〜２０００００がよい。また、かかる粘度指数向上剤は、単独で又は複数種を任意に組合せて含有させることができるが、通常その含有量は、潤滑油組成物基準で０．１〜４０．０％であることが望ましい。
【００７１】
さらにまた、他の無灰摩擦調整剤としては、ホウ酸エステル、高級アルコール、脂肪族エーテル等の無灰摩擦調整剤、ジチオリン酸モリブデン、ジチオカルバミン酸モリブデン、二硫化モリブデン等の金属系摩擦調整剤等が挙げられ、他の無灰分散剤としては、数平均分子量が９００〜３５００のポリブテニル基を有するポリブテニルベンジルアミン、ポリブテニルアミン、数平均分子量が９００未満のポリブテニル基を有するポリブテニルコハク酸イミド等及びそれらの誘導体等が挙げられる。
【００７２】
さらにまた、上記磨耗防止剤又は極圧剤としては、ジスルフィド、硫化油脂、硫化オレフィン、炭素数２〜２０の炭化水素基を１〜３個含有するリン酸エステル、チオリン酸エステル、亜リン酸エステル、チオ亜リン酸エステル及びこれらのアミン塩等が挙げられる。
【００７３】
さらにまた、上記防錆剤としては、アルキルベンゼンスルフォネート、ジノニルナフタレンスルフォネート、アルケニルコハク酸エステル、多価アルコールエステル等が挙げられ、上記非イオン系界面活性剤及び抗乳化剤としては、ポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルフェニルエーテル、ポリオキシエチレンアルキルナフチルエーテル等のポリアルキレングリコール系非イオン系界面活性剤等が挙げられる。
【００７４】
さらにまた、上記金属不活性化剤としては、イミダゾリン、ピリミジン誘導体、チアジアゾール、ベンゾトリアゾール、チアジアゾール等が挙げられ、上記消泡剤としては、シリコーン、フルオロシリコーン、フルオロアルキルエーテル等が挙げられる。
【００７５】
なお、これら添加剤を本発明のバルブ装置に用いる潤滑油組成物に含有させる場合には、その含有量は、潤滑油組成物全量基準で、他の摩擦調整剤、他の無灰分散剤、磨耗防止剤又は極圧剤、防錆剤、及び抗乳化剤については０．０１〜５％、金属不活性剤については０．００５〜１％、消泡剤については０．０００５〜１％の範囲から適宜選択することができる。
【００７６】
【実施例】
以下、本発明を実施例及び比較例により具体的に説明するが、本発明は、これら実施例のみに限定されるものではない。
【００７７】
実施例１〜１０及び比較例１では、後記する表１に示すように、バルブ軸に相当するピン状の試料と、その摺動相手部材（軸受部）であるリング状の摺動相手試料を用意した。そして、実施例１及び２については、試料及び摺動相手試料の双方の摺動接触面にＤＬＣ被膜を形成し、実施例３〜１０については、試料の摺動接触面にＤＬＣ被膜を形成し、比較例１については、ＤＬＣ被膜が無いものとし、また、各例において基材の面粗度、ＤＬＣ被膜の膜厚及び水素含有量、並びに潤滑油中の添加剤を異ならせた。
【００７８】
次に、ＪＩＳ Ｄ４４１１に準処して、定速式摩擦試験機において、試料（ピン）と摺動相手試料（リング）を用いたピン−オン−リングによる摩擦試験を行った。この試験は、摺動相手材料に対して試料を一定荷重で押付けるとともにリングを定速度で回転させて摩擦力を測定するものである。そして、測定した摩擦力や試験前後に行った試料の厚さ及び重量の測定結果に基づいて摩擦係数を求めて、比較例１及び２を『１．００』として実施例１〜１０及び実施例１１〜２０の摩擦係数低減比を求めた。その結果を表１及び表２に示す。
【００７９】
【表１】

【００８０】
表１に示すように、実施例１〜１０については、ＤＬＣ被膜の形成により、比較例１対して摩擦係数が明らかに低減されたものとなり、とくに、試料及び相手摺動部材の両方にＤＬＣ被膜を形成した実施例１及び２については、摩擦係数の大幅な低減を確認することができた。
【図面の簡単な説明】
【図１】本発明に係わるエンジンのバルブ装置の一実施形態として、可変吸気コントロールバルブを説明する分解斜視図（ａ）、リップシール部分の断面図（ｂ）、負圧式アクチュエータ部分の側面図（ｃ）、及びインテークマニホルドのフランジ部分の正面図（ｄ）である。
【図２】本発明に係わるエンジンのバルブ装置の他の実施形態として、スワールコントロールバルブを説明する断面図（ａ）、開いた状態のバルブ正面図（ｂ）、閉じた状態のバルブ正面図（ｃ）、及び側部断面図（ｄ）である。
【図３】本発明に係わるエンジンのバルブ装置の他の実施形態としてスロットルバルブを説明する図であって、バルブ軸及び軸受部の異なる形態を示す各々バルブ正面図（ａ）〜（ｃ）である。
【符号の説明】
４ １４ ２３ バルブ
５ １５ ２４ バルブ軸
６ １６ ２５ 軸受部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a butterfly-type valve device used for, for example, a variable intake control valve, a swirl control valve, a throttle valve and the like in an automobile engine.
[0002]
[Prior art]
Valve devices such as engine variable intake control valves and swirl control valves use butterfly valves that open and close the intake path. These valve devices have a structure in which a plate-like valve is attached to a valve shaft, the valve shaft is rotatably held by a bearing portion, and the valve shaft is rotated by a negative pressure type or motor type actuator. Even in the throttle valve, the basic structure is the same as that of the valve device.
[0003]
Here, in the valve device described above, the valve shaft and the bearing portion are in sliding contact. Particularly in the variable intake control valve and the swirl control valve, the air moment due to the intake air, the vibration of the engine, the low temperature environment, etc. Since the friction of the sliding contact portion increases due to the influence of the actuator, an actuator that can sufficiently cope with the load is used.
[0004]
In recent years, the engine idling speed has been reduced from the viewpoint of improving the performance of the engine and protecting the environment. In order to achieve this, it is necessary to control the intake air during idling to a low amount. At this time, in the throttle valve that controls the air amount, it is important to reduce the amount of air leakage in the fully closed state, and since this air leakage often occurs around the valve shaft, Has taken measures such as applying molybdenum around the valve shaft in order to reduce the gap between the sliding contact portions of the valve shaft and the bearing portion.
[0005]
[Problems to be solved by the invention]
However, in the valve device as described above, the variable intake control valve and the swirl control valve require a large actuator to cope with the friction generated in the sliding contact portion between the valve shaft and the bearing portion. There was a problem that it was disadvantageous in terms of speed, power consumption and cost. Also, in throttle valves, molybdenum is applied to the valve shaft in order to reduce the clearance between the sliding contact portion between the valve shaft and the bearing section, so that workability, quality, durability, etc. There was a problem of being disadvantageous.
[0006]
In the conventional valve device described above, the large actuator and the application work of molybdenum are caused by the friction generated in the sliding contact portion between the valve shaft and the bearing portion. There has been a demand for an improvement in reducing friction at the moving contact portion.
[0007]
OBJECT OF THE INVENTION
The present invention has been made in view of the above-described conventional situation, and in a valve device provided in an intake passage of an engine or the like, a significant reduction in friction is realized at a sliding contact portion between a valve shaft and a bearing portion. An object of the present invention is to provide an engine valve device that can perform the above-described operation.
[0008]
[Means for Solving the Problems]
The valve device of the engine of the present invention is a valve device provided in an intake passage or the like of the engine, in a portion where a valve shaft provided with the valve and a bearing portion that rotatably holds the valve shaft are in sliding contact with each other, It is characterized in that a hard carbon film is formed on at least one sliding contact surface of the valve shaft and the bearing portion, and more preferably, it is made in sliding contact in the presence of a specific lubricating oil. Realizes a significant reduction in
[0009]
【The invention's effect】
According to the valve device for an engine of the present invention, friction can be significantly reduced at the sliding contact portion between the valve shaft and the bearing portion. As a result, valve devices such as variable intake control valves and swirl control valves can reduce the size of the drive actuator and simplify the structure as the friction is reduced. In addition, the response speed can be improved, the power can be saved, the fuel consumption can be improved and the cost can be reduced, and the engine performance can be further improved.
[0010]
In addition, in a valve device such as a throttle valve, the clearance between the valve shaft and the bearing portion can be reduced along with the reduction of friction, and the amount of air leakage when fully closed can be reduced, improving engine performance. In addition to making a contribution, it is possible to eliminate the application of molybdenum to reduce the clearance, thereby improving workability, reducing costs, improving quality, and improving durability.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail. In the present specification, “%” indicates mass percentage unless otherwise specified.
[0012]
FIG. 1 is a diagram for explaining a variable intake control valve as an engine valve device. This valve is a butterfly type valve, and is provided in each intake passage corresponding to each cylinder in the intake manifold 1 to increase the length of the effective intake port by closing at low and medium speeds. By opening at high speed, the length of the effective intake port is reduced to improve the torque in each rotation region.
[0013]
The variable intake control valve includes a plate-like valve 4 that opens and closes a port 3 formed on the flange 2 of the intake manifold 1 and a valve shaft 5 that passes through the intake manifold 1 so as to pass through each port 3. Each valve 4 is screwed to the valve shaft 5. The valve shaft 5 is made of an iron-based material. In the intake manifold 1, the valve shaft 5 is rotatably held by bearings 6 on both sides of each valve 4, and both ends are rotated by a lip seal 7 made of a rubber-based material. It is held freely. Note that grease is applied to the lip seal 7.
[0014]
A rotation lever 8 is connected to one end of the valve shaft 5, and a connecting pin 9 is provided at a position offset from the valve shaft 5. Is connected to the output rod 10a of the negative pressure actuator 10. Thus, when the variable intake control valve drives the output rod 10a of the negative pressure actuator 10 to advance and retreat, the valve shaft 5 reciprocates through the rotation lever 8, and at the same time, the valve 4 reciprocates to rotate the port. 3 is opened and closed.
[0015]
At this time, in the variable intake control valve, the valve shaft 3 provided with the valve 4 and the bearing portion 6 and the lip seal 7 which hold the valve shaft 3 so as to be rotatable are in sliding contact. Accordingly, the variable intake control valve has a hard carbon film formed on at least one sliding contact surface of the valve shaft 5, the bearing portion 6 and the lip seal 7, thereby greatly reducing friction at the sliding contact portion. ing. In terms of ease of film formation, it is desirable to form a hard carbon film on the valve shaft 5.
[0016]
Thus, if the friction at the sliding contact portion is reduced, the small negative pressure actuator 10 can sufficiently drive the valve 4 even if it is affected by the air moment due to the intake air, the vibration of the engine, the low temperature environment, and the like. This also eliminates the need for an amplifying mechanism such as a crank mechanism for increasing torque, which increases the degree of freedom in equipment layout, improves response speed, saves power, and improves fuel consumption due to power savings. Cost reduction can be realized.
[0017]
FIG. 2 is a diagram illustrating a swirl control valve as an engine valve device. This valve is a butterfly valve, and is provided in each intake passage corresponding to each cylinder in the intake manifold 11, and in particular, the intake passages 13a and 13b branched into two for each cylinder. One of the intake passages 13a is opened and closed.
[0018]
The swirl control valve is configured to pass through each intake passage 3a with respect to the intake manifold 11 and a plate-like valve 14 that opens and closes the intake passage 3a in the intake manifold 11 in the same manner as the variable intake control valve. A valve shaft 15 is provided, and each valve 14 is screwed to the valve shaft 15. The valve shaft 15 is made of an iron-based material. In the intake manifold 11, the valve shaft 15 is rotatably held by bearings 16 on both sides of each valve 14, and both ends are rotated by a lip seal 17 made of a rubber-based material. It is held freely.
[0019]
A rotating lever 18 is connected to one end of the valve shaft 15, and a connecting pin 19 is provided at a position offset from the valve shaft 15. The output rod 20a of the electronic control motor type actuator 20 is connected to this. Thereby, when the output rod 20a of the electronic control motor type actuator 20 is driven forward and backward, the swirl control valve reciprocates the valve shaft 15 via the rotation lever 18, and simultaneously the valve 14 reciprocates. The intake passage 3a is opened and closed.
[0020]
At this time, in the swirl control valve, the valve shaft 13 including the valve 14, and the bearing portion 16 and the lip seal 17 that hold the valve shaft 13 so as to be rotatable are in sliding contact. Therefore, the swirl control valve forms a hard carbon film on at least one sliding contact surface of the valve shaft 15 and the bearing portion 16 and the lip seal 17, thereby greatly reducing friction at the sliding contact portion. Yes. In terms of ease of film formation, it is desirable to form a hard carbon film on the valve shaft 15.
[0021]
In this way, if the friction at the sliding contact portion is reduced, the valve 14 can be sufficiently connected even with the small electronically controlled motor type actuator 20 even if it is affected by the air moment due to the intake air, the vibration of the engine and the low temperature environment. As a result, the degree of freedom in the layout of the device can be increased, and the response speed can be improved, the power can be saved, the fuel consumption can be improved, and the cost can be reduced.
[0022]
FIG. 3 is a diagram for explaining a throttle valve in an engine as an engine valve device. As is well known, this valve is a butterfly valve that opens and closes the intake path in conjunction with the operation of the accelerator pedal.
[0023]
The throttle valve includes a plate-like valve 23 that opens and closes an intake passage 22 and a valve shaft 24 that is provided across the intake passage 22 in a valve housing 21 that forms part of the air duct. The valve 23 is screwed to 24. The valve shaft 24 is made of an iron-based material, and both ends are rotatably held by the bearing portion 25.
[0024]
Here, in the throttle valve shown in FIG. 3A, the bearing portion 25 that holds one end portion of the valve shaft 24 includes a bearing 25 </ b> A and a through hole 25 </ b> B formed in the valve housing 21. The inner peripheral surface of the through hole 25B comes into sliding contact. Therefore, in this throttle valve, a hard carbon film is formed on at least one sliding contact surface of the valve shaft 24 and the through hole 25B, thereby greatly reducing friction at the sliding contact portion.
[0025]
In the throttle valve shown in FIG. 3B, the bearing portion 25 that holds one end of the valve shaft 24 is a holding hole (25) formed in the valve housing 21, and the valve shaft 24 and the holding hole (25). In contact with the inner peripheral surface. Therefore, in this throttle valve, a hard carbon film is formed on at least one sliding contact surface of the valve shaft 24 and the holding hole (25), thereby greatly reducing friction at the sliding contact portion.
[0026]
Further, in the throttle valve shown in FIG. 3 (c), the bearing portion 25 that holds one end portion of the valve shaft 24 is constituted by a bearing 25 A and a through hole 25 B formed in the valve housing 21. A flange portion 24a is formed, the valve shaft 24 and the inner peripheral surface of the through hole 25B are in sliding contact, and the end surface of the flange portion 24a and the inner wall of the intake passage 22 substantially included in the bearing portion 25 are formed. Sliding contact. Therefore, in this throttle valve, a hard carbon coating is formed on at least one sliding contact surface between the valve shaft 24 including the flange portion 24a and the bearing portion 25 including the through hole 25B and the inner wall of the intake path, thereby sliding. Friction at the contact area is greatly reduced.
[0027]
In each of the valve devices shown in FIGS. 3 (a) to 3 (c), as the friction in the sliding contact portion is reduced, the clearance of the sliding contact portion can be set small. The amount of air leakage when fully closed can be reduced, which can contribute to improvement in engine performance. In addition, it is possible to eliminate the application of molybdenum to reduce the clearance as before, improving workability, reducing costs, improving quality (stability of flow control values), and durability (flow rate characteristics after deterioration). ) Improvement. In each valve device shown in FIG. 3, it is desirable to form a hard carbon coating on the valve shaft 24 in terms of ease of film formation.
[0028]
Further, in each of the valve devices shown in FIGS. 1 to 3, during operation of the engine, blow bioile (for example, engine oil) adheres to the sliding contact portion, and the oil acts as a lubricating oil. The friction reduction effect is further exhibited by sliding contact in the presence of oil.
[0029]
Here, in each valve device shown in FIGS. 1 to 3, the hard carbon thin film formed on the sliding contact portion between the valve shaft and the bearing portion is subjected to various PVD methods, specifically, arc ion plating methods. A formed DLC thin film (diamond-like carbon thin film) is desirable. This DLC thin film is an amorphous material mainly composed of carbon element, and specifically, a-C (amorphous carbon) composed only of carbon element, aC: H (hydrogen amorphous containing hydrogen). Carbon), and MeC (metal carbon or metal carbide) partially containing metal elements such as titanium (Ti) and molybdenum (Mo). From the viewpoint of exerting a significant friction reducing effect, the hydrogen content is The smaller the content, the more preferable, the hydrogen atom content is 10.0 atom% or less, more preferably the hydrogen atom content is 1.0 atom% or less, and further no aC-based (amorphous carbon) material containing hydrogen. The film thickness is preferably 0.3 to 1.5 μm.
[0030]
Here, when the surface roughness of the valve shaft made of iron-based material or the base material of the bearing portion, that is, the surface roughness of the sliding contact surface before coating with the hard carbon thin film exceeds 0.08 μm, it is hard. Since the protrusion due to the roughness of the carbon thin film surface increases the local contact area with the sliding partner and induces cracking of the film, the surface of the sliding contact surface before coating the hard carbon thin film The roughness is preferably 0.08 μm or less in terms of Ra, and more preferably the surface roughness of the sliding contact surface before coating of the hard carbon thin film is 0.03 μm or less in terms of Ra. It is also effective to prevent cracking of the above-mentioned film by setting the surface roughness of the induction (sliding error) contact surface where the hard carbon thin film is not formed (not formed) to Ra of 0.08 μm or less. It is.
[0031]
Next, the lubricating oil composition used in the valve device of the present invention will be described in detail. This lubricating oil composition comprises a lubricating base oil containing a fatty acid ester-based ashless friction modifier and / or an aliphatic amine-based ashless friction modifier.
[0032]
The lubricating base oil is not particularly limited, and any type of base oil can be used as long as it is normally used as a base oil of a lubricating oil composition, such as mineral oil, synthetic oil, fats and oils, and mixtures thereof. be able to.
[0033]
As mineral oil, specifically, lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil can be desolvated, solvent extraction, hydrocracking, solvent dewaxing, hydrorefining, sulfuric acid washing, clay treatment Paraffinic or naphthenic oils or normal paraffins, etc., which are refined by appropriately combining purification treatments such as the above, can be used, and those that have been subjected to solvent purification and hydrorefining treatment are common, but the aromatic content is further reduced It is more preferable to use an advanced hydrocracking process or GTL Wax (gas tow liquid wax) produced by isomerization.
[0034]
Specific examples of synthetic oils include poly-α-olefins (eg, 1-octene oligomers, 1-decene oligomers, ethylene-propylene oligomers), poly-α-olefin hydrides, isobutene oligomers, and isobutene oligomers. Hydride, isoparaffin, alkylbenzene, alkylnaphthalene, diester (eg, ditridecyl glutarate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, dioctyl sebacate, etc.), polyol ester (eg, trimethylolpropane caprylate, trimethylolpropane pelargol And trimethylolpropane esters such as trimethylolpropane isostearinate; pentaerythritol 2-ethylhexanoate, pentaerythritol Pentaerythritol esters such as largonate), polyoxyalkylene glycols, dialkyldiphenyl ethers, polyphenyl ethers and the like. Among them, preferred examples include poly-α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof.
[0035]
The base oil of the lubricating oil composition used in the valve device of the present invention may be a mineral base oil or a synthetic base oil used alone or in combination, or two or more mineral base oils or two or more synthetic base oils. It can be a mixture of base oils. Further, the mixing ratio of two or more kinds of base oils in the above mixture is not particularly limited and can be arbitrarily selected.
[0036]
The sulfur content in the lubricating base oil is not particularly limited, but is preferably 0.2% or less, more preferably 0.1% or less, and even more preferably 0.05% or less, based on the total amount of the base oil. Preferably there is. In particular, since the sulfur content of hydrorefined mineral oil or synthetic base oil is 0.005% or less, or contains substantially no sulfur content (5 ppm or less), these are preferably used as the base oil.
[0037]
Further, the aromatic content in the lubricating base oil is not particularly limited, but in order to maintain a low friction characteristic for a long period of time as a lubricating oil composition for an internal combustion engine, the total aromatic content is 15% or less. Preferably, it is 10% or less, more preferably 5% or less. That is, when the total aromatic content of the lubricating base oil exceeds 15%, oxidation stability is inferior, which is not preferable.
[0038]
In addition, the total aromatic content said here means the aromatic fraction content measured based on the method prescribed | regulated to ASTMD2549.
[0039]
The kinematic viscosity of the lubricating base oil is not particularly limited, but when used as a lubricating oil composition for an internal combustion engine, the kinematic viscosity at 100 ° C. is preferably 2 mm ² / s or more, more preferably. 3 mm ² / s or more. On the other hand, the kinematic viscosity is preferably 20 mm ² / s or less, preferably 10 mm ² / s or less, and particularly preferably 8 mm ² / s or less. When the kinematic viscosity of the lubricating base oil at 100 ° C. is less than 2 mm ² / s, it is not preferable because sufficient abrasion resistance cannot be obtained and evaporation characteristics may be deteriorated. On the other hand, when the kinematic viscosity of the lubricating base oil at 100 ° C. exceeds 20 mm ² / s, it is not preferable because low friction performance is hardly exhibited and low temperature performance may be deteriorated. In the valve device of the present invention, a mixture or the like in which two or more kinds of base oils selected from the above base oils are arbitrarily mixed can be used, so long as the kinematic viscosity at 100 ° C. falls within the above preferred range, Even if the kinematic viscosity of the base oil alone is other than the above, it can be used.
[0040]
The viscosity index of the lubricating base oil is not particularly limited, but is preferably 80 or more, more preferably 100 or more, particularly when used as a lubricating oil composition for an internal combustion engine. 120 or more. By increasing the viscosity index of the lubricating base oil, it is possible to obtain a lubricating oil composition for an internal combustion engine with less oil consumption and excellent low-temperature viscosity characteristics.
[0041]
The fatty acid ester ashless friction modifier and / or the aliphatic amine ashless friction modifier is a straight chain having 6 to 30 carbon atoms, preferably 8 to 24 carbon atoms, and particularly preferably 10 to 20 carbon atoms. Or the fatty acid ester which has a branched hydrocarbon group, a fatty-acid amine compound, and these arbitrary mixtures can be mentioned. When the carbon number is outside the range of 6 to 30, there is a possibility that the friction reducing effect cannot be obtained sufficiently.
[0042]
Specific examples of the straight chain or branched hydrocarbon group having 6 to 30 carbon atoms include hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group. Group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, triaconyl group, etc. Alkyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group, icosenyl group, N'ikoseniru group include docosenyl, tricosenyl group, tetracosenyl group, Pentakoseniru group, Hekisakoseniru group, Heputakoseniru group, Okutakoseniru group, Nonakoseniru group, an alkenyl group such as tri container group. The alkyl group and alkenyl group include all possible linear structures and branched structures, and the position of the double bond in the alkenyl group is arbitrary.
[0043]
Moreover, as said fatty acid ester, the ester of the fatty acid which has this C6-C30 hydrocarbon group, and aliphatic monohydric alcohol or aliphatic polyhydric alcohol etc. can be illustrated, Specifically, glycerol monooleate, Particularly preferred examples include glycerine diolate, sorbitan monooleate, sorbitan diolate, and the like.
[0044]
Examples of the aliphatic amine compound include aliphatic monoamines or their alkylene oxide adducts, aliphatic polyamines, imidazoline compounds, and derivatives thereof. Specifically, fats such as laurylamine, lauryldiethylamine, lauryldiethanolamine, dodecyldipropanolamine, palmitylamine, stearylamine, stearyltetraethylenepentamine, oleylamine, oleylpropylenediamine, oleyldiethanolamine, N-hydroxyethyloleylimidazoline, etc. Amine alkylene compounds, amine alkylene oxide adducts such as N, N-dipolyoxyalkylene-N-alkyl (or alkenyl) (carbon number 6 to 28) of these aliphatic amine compounds, carbon numbers in these aliphatic amine compounds Residual amino group and / or imino by reacting 2-30 monocarboxylic acid (fatty acid, etc.) or polycarboxylic acid having 2-30 carbon atoms such as oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc. Base Some or amidated or neutralize all, so-called acid-modified compounds, and the like. Preferable examples include N, N-dipolyoxyethylene-N-oleylamine.
[0045]
Further, the content of the fatty acid ester-based ashless friction modifier and / or the aliphatic amine-based ashless friction modifier contained in the lubricating oil composition used in the valve device of the present invention is 0 based on the total amount of the lubricating oil composition. The content is preferably 0.05 to 3.0%, more preferably 0.1 to 2.0%, and particularly preferably 0.5 to 1.4%. If the content is less than 0.05%, the friction reducing effect tends to be small, and if it exceeds 3.0%, the solubility and storage stability in the lubricating oil are significantly deteriorated, and precipitates are likely to be generated. It is not preferable.
[0046]
On the other hand, the lubricating oil composition used in the valve device of the present invention preferably contains polybutenyl succinimide and / or a derivative thereof, and the polybutenyl succinimide has the following general formula ( Examples thereof include compounds represented by 1) and (2).
[0047]
[Chemical 1]

[0048]
[Chemical 2]

[0049]
PIB in these general formulas represents a polybutenyl group, and the number average molecular weight obtained by polymerizing a high purity isobutene or a mixture of 1-butene and isobutene with a boron fluoride catalyst or an aluminum chloride catalyst is 900 to 3500, preferably Obtained from 1000-2000 polybutene. When the number average molecular weight is less than 900, the cleanability effect tends to be poor, and when it exceeds 3500, the low temperature fluidity tends to be poor.
[0050]
Further, n in the above general formula is preferably an integer of 1 to 5, more preferably an integer of 2 to 4, from the viewpoint of excellent cleanability. Further, the polybutene is used to remove a trace amount of fluorine and chlorine remaining due to the catalyst in the production process by an appropriate method such as an adsorption method or sufficient water washing, and is preferably 50 ppm or less, more preferably 10 ppm or less, and particularly preferably 1 ppm. It is also possible to use after removing to the following.
[0051]
Furthermore, the method for producing the polybutenyl succinimide is not particularly limited. For example, the polybutene chlorinated product or polybutene from which chlorine or fluorine is sufficiently removed and maleic anhydride are reacted at 100 to 200 ° C. The polybutenyl succinic acid thus obtained can be obtained by reacting with polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and the like.
[0052]
On the other hand, as a derivative of the polybutenyl succinimide, a boron compound or an oxygen-containing organic compound is allowed to act on the compound represented by the general formula (1) or (2), thereby remaining amino groups and / or Examples thereof include so-called boron-modified or acid-modified compounds in which part or all of the imino group is neutralized or amidated. Among them, boron-containing polybutenyl succinimide, particularly boron-containing bispolybutenyl succinimide is most preferable.
[0053]
Examples of the boron compound include boric acid, borates, and borate esters. Specifically, examples of the boric acid include orthoboric acid, metaboric acid, and tetraboric acid. Moreover, as said borate, ammonium borate, such as ammonium salt etc., specifically, for example, ammonium metaborate, ammonium tetraborate, ammonium pentaborate, ammonium octaborate, etc. are mentioned as a suitable example. As the boric acid ester, an ester of boric acid and preferably an alkyl alcohol having 1 to 6 carbon atoms, more specifically, for example, monomethyl borate, dimethyl borate, trimethyl borate, monoethyl borate, boric acid Preferred examples include diethyl, triethyl borate, monopropyl borate, dipropyl borate, triplypropyl borate, monobutyl borate, dibutyl borate, tributyl borate and the like. In addition, the mass ratio “B / N” of the boron content B and the nitrogen content N in the boron-containing polybutenyl succinimide is usually 0.1 to 3, preferably 0.2 to 1. .
[0054]
Specific examples of the oxygen-containing organic compound include formic acid, acetic acid, glycolic acid, propionic acid, lactic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecyl. C1-C30 monocarboxylic acids such as acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, oleic acid, nonadecanoic acid, eicosanoic acid, oxalic acid, phthalic acid, C2-C30 polycarponic acid such as trimellitic acid and pyromellitic acid and their anhydrides or ester compounds, C2-C6 alkylene oxide, hydroxy (poly) oxyalkylene carbonate, and the like.
In the lubricating oil composition used in the valve device of the present invention, the content of polybutenyl succinimide and / or its derivative is desirably 0.1 to 15%, more desirably 1.0 to 12%. Preferably there is. If it is less than 0.1%, the cleaning effect may be poor, and if it exceeds 15%, it is difficult to obtain a cleaning effect corresponding to the content, and the demulsibility tends to deteriorate.
[0056]
Furthermore, the lubricating oil composition used for the valve device of the present invention preferably contains zinc dithiophosphate represented by the following general formula (3).
[0057]
[Chemical 3]

[0058]
R ⁴ , R ⁵ , R ⁶ and R ⁷ in the above formula (3) each independently represent a hydrocarbon group having 1 to 24 carbon atoms. Examples of these hydrocarbon groups include linear or branched alkyl groups having 1 to 24 carbon atoms, linear or branched alkenyl groups having 3 to 24 carbon atoms, and cycloalkyl groups having 5 to 13 carbon atoms. Or a linear or branched alkylcycloalkyl group, an aryl group having 6 to 18 carbon atoms, a linear or branched alkylaryl group, an arylalkyl group having 7 to 19 carbon atoms, or the like. It is desirable. The alkyl group or alkenyl group may be any of primary, secondary, and tertiary.
[0059]
Specific examples of R ⁴ , R ⁵ , R ⁶ and R ⁷ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, tetracosyl group, alkyl group, propenyl group, Isopropenyl group, butenyl group, butadienyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, oleyl Octadeseni Group, nonadecenyl group, icocenyl group, heicosenyl group, dococenyl group, tricocenyl group, tetracocenyl group and other alkenyl groups, cyclopentyl group, cyclohexyl group, cycloheptyl group and other cycloalkyl groups, methylcyclopentyl group, dimethylcyclopentyl group, ethyl Cyclopentyl group, propylcyclopentyl group, ethylmethylcyclopentyl group, trimethylcyclopentyl group, diethylcyclopentyl group, ethyldimethylcyclopentyl group, propylmethylcyclopentyl group, propylethylcyclopentyl group, di-propylcyclopentyl group, propylethylmethylcyclopentyl group, methylcyclohexyl Group, dimethylcyclohexyl group, ethylcyclohexyl group, propylcyclohexyl group, ethylmethylcyclohexyl , Trimethylcyclohexyl group, diethylcyclohexyl group, ethyldimethylcyclohexyl group, propylmethylcyclohexyl group, propylethylcyclohexyl group, di-propylcyclohexyl group, propylethylmethylcyclohexyl group, methylcycloheptyl group, dimethylcycloheptyl group, Ethylcycloheptyl group, propylcycloheptyl group, ethylmethylcycloheptyl group, trimethylcycloheptyl group, diethylcycloheptyl group, ethyldimethylcycloheptyl group, propylmethylcycloheptyl group, propylethylcycloheptyl group, di-propylcycloheptyl group Alkylcycloalkyl groups such as propylethylmethylcycloheptyl group, aryl groups such as phenyl group and naphthyl group, tolyl group, xylyl group, Nyl group, propylphenyl group, ethylmethylphenyl group, trimethylphenyl group, butylphenyl group, propylmethylphenyl group, diethylphenyl group, ethyldimethylphenyl group, tetramethylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group , Alkylaryl groups such as octylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, dodecylphenyl group, benzyl group, methylbenzyl group, dimethylbenzyl group, phenethyl group, methylphenethyl group, dimethylphenethyl group, etc. An arylalkyl group etc. can be illustrated.
[0060]
The hydrocarbon groups that R ⁴ , R ⁵ , R ^6, and R ⁷ can include all possible linear structures and branched structures, and also include double bonds of alkenyl groups. The position, the bonding position of the alkyl group to the cycloalkyl group, the bonding position of the alkyl group to the aryl group, and the bonding position of the aryl group to the alkyl group are arbitrary. Further, among the hydrocarbon groups, when the hydrocarbon group is a linear or branched alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a linear or branched group Particularly preferred is a linear alkylaryl group.
[0061]
Preferred examples of the zinc dithiophosphate include, for example, zinc diisopropyldithiophosphate, zinc diisobutyldithiophosphate, zinc di-sec-butyldithiophosphate, zinc di-sec-pentyldithiophosphate, zinc di-n-hexyldithiophosphate. , Zinc di-sec-hexyldithiophosphate, zinc di-octyldithiophosphate, zinc di-2-ethylhexyldithiophosphate, zinc di-n-decyldithiophosphate, zinc di-n-dodecyldithiophosphate, zinc diisotridecyldithiophosphate , And mixtures according to any combination thereof.
[0062]
Further, the content of the zinc dithiophosphate is preferably 0.1% or less in terms of the total amount of the lubricating oil composition and in terms of phosphorus element, from the viewpoint of exerting a higher friction reduction effect, and 0.06. % Or less is more preferable, and it is particularly preferable that zinc dithiophosphate is not contained. When the zinc dithiophosphate content exceeds 0.1% in terms of phosphorus element, the fatty acid ester-based ashless friction modifier and the aliphatic amine-based ashless friction on the sliding surface between the DLC member and the iron base member There exists a possibility that the outstanding friction reduction effect of a regulator may be inhibited.
[0063]
As a method for producing the zinc dithiophosphate, a conventional method can be arbitrarily adopted, and is not particularly limited. Specifically, for example, hydrocarbons corresponding to R ⁴ , R ⁵ , R ⁶ and R ⁷ are used. It can be synthesized by reacting a group-containing alcohol or phenol with phosphorus pentasulfide to dithiophosphoric acid and neutralizing it with zinc oxide. In addition, it cannot be overemphasized that the structure of the said zinc dithiophosphate changes with raw material alcohol to be used.
[0064]
In the present invention, two or more kinds of zinc dithiophosphates included in the general formula (3) may be mixed and used at an arbitrary ratio.
[0065]
As described above, in the valve device of the present invention, the lubricating oil composition is extremely used when used on a sliding contact surface coated with a hard carbon thin film, that is, at least one sliding contact surface of the valve shaft and the bearing portion. Exhibits excellent low friction characteristics, but for the purpose of enhancing the performance required especially as a lubricating oil composition for internal combustion engines, metal detergents, antioxidants, viscosity index improvers, and other ashless friction modifiers , Other ashless dispersants, antiwear or extreme pressure agents, rust inhibitors, nonionic surfactants, antiemulsifiers, metal deactivators, antifoaming agents, etc., alone or in combination. , Can enhance the required performance.
[0066]
As said metallic detergent, the arbitrary compounds normally used as a metallic detergent for lubricating oil can be used. For example, alkali metal or alkaline earth metal sulfonates, phenates, salicylate naphthenates and the like can be used alone or in combination. Here, examples of the alkali metal include sodium (Na) and potassium (K), and examples of the alkaline earth metal include calcium (Ca) and magnesium (Mg). Specific preferred examples include Ca or Mg sulfonates, phenates and salicylates.
[0067]
In addition, the total base number and addition amount of these metal detergents can be arbitrarily selected according to the required performance of the lubricating oil. Usually, the total base number is 0 to 500 mgKOH / g, desirably 150 to 400 mgKOH / g by the perchloric acid method, and the addition amount is usually 0.1 to 10% based on the total amount of the lubricating oil composition.
[0068]
Further, as the antioxidant, any compound usually used as an antioxidant for lubricating oil can be used. For example, phenolic antioxidants such as 4,4′-methylenebis (2,6-di-tert-butylphenol) and octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, phenyl Examples thereof include amine-based antioxidants such as -α-naphthylamine, alkylphenyl-α-naphthylamine, and alkyldiphenylamine, as well as mixtures according to any combination thereof. Moreover, the addition amount of this antioxidant is 0.01 to 5% normally on the basis of the total amount of the lubricating oil composition.
[0069]
Furthermore, as the viscosity index improver, specifically, a so-called non-dispersion type viscosity index improver such as a copolymer of one or two or more monomers selected from various methacrylic acid esters and hydrogenated products thereof, Furthermore, a so-called dispersion type viscosity index improver obtained by copolymerizing various methacrylic acid esters containing a nitrogen compound can be exemplified. Specific examples of other viscosity index improvers include non-dispersed or dispersed ethylene-α-olefin copolymers (eg, α-olefins include propylene, 1-butene, 1-pentene, etc.) and hydrogen thereof. Examples thereof include a compound, polyisobutylene and a hydrogenated product thereof, a styrene-diene hydrogenated copolymer, a styrene-maleic anhydride ester copolymer, and a polyalkylstyrene.
[0070]
The molecular weight of these viscosity index improvers needs to be selected in consideration of shear stability. Specifically, the number average molecular weight of the viscosity index improver is, for example, 5,000 to 1,000,000, preferably 100,000 to 800,000 for dispersed and non-dispersed polymethacrylates, 800 to 5,000 for polyisobutylene or a hydride thereof, ethylene- In the case of an α-olefin copolymer or a hydride thereof, 800 to 300,000, preferably 10,000 to 200,000 is preferable. In addition, the viscosity index improver can be contained alone or in any combination of two or more, but the content is usually 0.1 to 40.0% based on the lubricating oil composition. desirable.
[0071]
Furthermore, other ashless friction modifiers include ashless friction modifiers such as boric acid esters, higher alcohols and aliphatic ethers, metal friction modifiers such as molybdenum dithiophosphate, molybdenum dithiocarbamate, and molybdenum disulfide. Examples of other ashless dispersants include polybutenylbenzylamine having a polybutenyl group having a number average molecular weight of 900 to 3,500, polybutenylamine, and polybutenyl succinic acid having a polybutenyl group having a number average molecular weight of less than 900. Examples thereof include acid imides and derivatives thereof.
[0072]
Furthermore, as the above-mentioned antiwear or extreme pressure agent, disulfide, sulfurized fat and oil, sulfurized olefin, phosphate ester containing 1 to 3 hydrocarbon groups having 2 to 20 carbon atoms, thiophosphate ester, phosphite ester , Thiophosphite esters and amine salts thereof.
[0073]
Furthermore, examples of the rust preventive include alkylbenzene sulfonate, dinonyl naphthalene sulfonate, alkenyl succinic acid ester, polyhydric alcohol ester, and the like. Examples include polyalkylene glycol nonionic surfactants such as oxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.
[0074]
Furthermore, examples of the metal deactivator include imidazoline, pyrimidine derivatives, thiadiazole, benzotriazole, thiadiazole, and examples of the antifoaming agent include silicone, fluorosilicone, and fluoroalkyl ether.
[0075]
In addition, when these additives are included in the lubricating oil composition used in the valve device of the present invention, the content is based on the total amount of the lubricating oil composition, other friction modifiers, other ashless dispersants, wear. From 0.01 to 5% for inhibitor or extreme pressure agent, rust inhibitor and demulsifier, from 0.005 to 1% for metal deactivator and from 0.0005 to 1% for antifoaming agent. It can be selected appropriately.
[0076]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited only to these Examples.
[0077]
In Examples 1 to 10 and Comparative Example 1, as shown in Table 1 to be described later, a pin-shaped sample corresponding to the valve shaft and a ring-shaped sliding counterpart sample that is a sliding counterpart member (bearing portion) Prepared. And about Example 1 and 2, a DLC film is formed in the sliding contact surface of both a sample and a sliding other party sample, and about Examples 3-10, a DLC film is formed in the sliding contact surface of a sample. In Comparative Example 1, it was assumed that there was no DLC film, and in each example, the surface roughness of the substrate, the film thickness and hydrogen content of the DLC film, and the additive in the lubricating oil were varied.
[0078]
Next, in accordance with JIS D4411, a pin-on-ring friction test using a sample (pin) and a sliding counterpart sample (ring) was performed in a constant speed friction tester. In this test, a sample is pressed against a sliding material with a constant load, and a ring is rotated at a constant speed to measure a friction force. Then, the coefficient of friction was obtained based on the measured friction force and the measurement results of the thickness and weight of the sample before and after the test, and Comparative Examples 1 and 2 were set to “1.00” and Examples 1 to 10 and Examples A friction coefficient reduction ratio of 11 to 20 was obtained. The results are shown in Tables 1 and 2.
[0079]
[Table 1]

[0080]
As shown in Table 1, in Examples 1 to 10, the formation of the DLC film resulted in a clearly reduced coefficient of friction with respect to Comparative Example 1. In particular, the DLC film was applied to both the sample and the counterpart sliding member. As for Examples 1 and 2 in which s were formed, a significant reduction in the friction coefficient could be confirmed.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view (a) illustrating a variable intake control valve as an embodiment of a valve device for an engine according to the present invention, a sectional view (b) of a lip seal portion, and a side view of a negative pressure actuator portion (FIG. c) and a front view (d) of the flange portion of the intake manifold.
FIG. 2 is a cross-sectional view (a) illustrating a swirl control valve as another embodiment of the valve device for an engine according to the present invention, a front view of the valve in an open state (b), and a front view of the valve in a closed state ( It is c) and side part sectional drawing (d).
FIG. 3 is a view for explaining a throttle valve as another embodiment of the valve device of the engine according to the present invention, and is a front view of the valve (a) to (c) showing different forms of the valve shaft and the bearing portion, respectively. is there.
[Explanation of symbols]
4 14 23 Valve 5 15 24 Valve shaft 6 16 25 Bearing

Claims (12)

A valve device provided in an intake path or the like of an engine, wherein a valve shaft provided with a valve and a bearing portion that rotatably holds the valve shaft are in sliding contact with at least one of the valve shaft and the bearing portion. An intake valve device for an engine, wherein a hard carbon coating is formed on the sliding contact surface. 2. The engine valve device according to claim 1, wherein the hard carbon thin film has a thickness of 0.3 to 1.5 [mu] m. The valve device for an engine according to claim 1 or 2, wherein the amount of hydrogen atoms contained in the hard carbon thin film is 10.0 atomic% or less. 4. The engine valve device according to claim 3, wherein the amount of hydrogen atoms contained in the hard carbon thin film is 1.0 atomic% or less. 6. The valve shaft and the bearing portion are in sliding contact in the presence of a lubricating oil containing a fatty acid ester-based ashless friction modifier and / or an aliphatic amine-based ashless friction modifier. The valve device for an engine according to any one of the above. The fatty acid ester-based ashless friction modifier and / or the aliphatic amine-based ashless friction modifier has a hydrocarbon group having 6 to 30 carbon atoms, and 0.05 to 3.3 based on the total amount of the composition in the lubricating oil. 6. The valve device for an engine according to claim 5, wherein the content is 0%. The engine valve device according to claim 5 or 6, wherein the lubricating oil contains polybutenyl succinimide and / or a derivative thereof. 8. The valve device for an engine according to claim 7, wherein the content of polybutenyl succinimide and / or a derivative thereof in the lubricating oil is 0.1 to 15% based on the total amount of the lubricating oil composition. The engine valve device according to any one of 5 to 8, wherein the lubricating oil contains 0.1% or less of zinc dithiophosphate in terms of the total amount of the composition and in terms of phosphorus element. The engine valve device according to any one of claims 1 to 9, wherein the hard carbon thin film is a DLC thin film formed by a PVD method. 11. The engine valve device according to claim 1, wherein the surface roughness of the sliding contact surface before coating with the hard carbon thin film is 0.08 μm or less in terms of Ra. The valve device for an engine according to claim 11, wherein the surface roughness of the sliding contact surface before coating with the hard carbon thin film is 0.03 µm or less in Ra.

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