JP2004092567A

JP2004092567A - Variable valve system of engine

Info

Publication number: JP2004092567A
Application number: JP2002256776A
Authority: JP
Inventors: Toshihide Yamamoto; 山本　寿英; Shinichi Sugihara; 杉原　真一
Original assignee: Mazda Motor Corp
Current assignee: Mazda Motor Corp
Priority date: 2002-09-02
Filing date: 2002-09-02
Publication date: 2004-03-25
Anticipated expiration: 2022-09-02
Also published as: JP3835379B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve system of an engine, which can form oil supply passages for timing advance and timing retard while controlling upsizing of the engine. <P>SOLUTION: A hydraulic phase variable mechanism consists of a casing member connected to a camshaft driving member, a rotating member connected to a camshaft, and a timing advance chamber and a timing retard chamber that are formed between the casing member and the rotating member. Either of the oil supply passage for timing advance that communicates the timing advance chamber with an oil pressure source or the oil supply passage for timing retard that communicates the timing retard chamber with the oil pressure source is groovely formed on the connecting surface of a cylinder head 1 and a cam holder 6, and the other passage is groovely formed on the connecting surface of the cam holder 6 and a cam cap 7. As a result, since each of the oil supply passage for timing advance and the oil supply passage for timing retard is formed on the different connecting surface, increase in the number of passages formed on the same surface can be curbed. In addition, this structure can control the width of parts comprising bearings of the cam shafts 2 and 3, and the total length of the engine. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、エンジンの可変動弁装置に関し、特に、油圧式の位相可変機構を備えたエンジンの可変動弁装置に関するものである。
【０００２】
【従来の技術】
従来、この種のエンジンのバルブタイミング制御装置としては、カムシャフトの一端側に油圧式の位相可変機構を設け、スプロケットやタイミングプーリとカムシャフトとの位相を変化させることが知られている。
例えば、特開平９−１９５８０５号公報にも開示されているように、位相可変機構は、カムシャフトの一端側端部においてカムプーリに一体的に連結されるケーシングと、そのケーシング内に勘合され、カムシャフトに一体的に連結されるロータとから構成されている。ケーシングには、中空円筒状に形成されるとともに、その中空円筒内面に中空円筒の中心に向かって延びる４つの突出部が形成され、ロータには、円筒状のボス部の外周から径方向外方に延びる４つのベーンが形成されている。そして、ケーシングに形成された４つの突出部とロータに形成された４つのベーンとは周方向に交互に配置されて８つの受圧室が形成され、この８つの受圧室の内、ロータの各ベーンに対しカムシャフトの回転側に位置づけられた４つの受圧室が遅角室として構成される一方、この遅角室の反対側に位置づけられた４つの受圧室が進角室として構成される。
このような位相可変機構においては、遅角室と油圧源とが連通されると、遅角室の油圧が増大されてロータがケーシングに対しカムシャフトの回転と反対側に回動され、これによってバルブタイミングを遅角側に変更することができる一方、進角室が油圧源と連通されると、進角室の油圧が増大されてロータがケーシングに対しカムシャフトの回転する側に回動され、これによってバルブタイミングを進角側に変更することができるものである。
【０００３】
【発明が解決しようとする課題】
ところで、上述の先行技術のように油圧式の位相可変機構を備えた場合、進角室と油圧源とを連通する進角用給油通路と、遅角室と油圧源とを連通する遅角用給油通路とを追加する必要がある。
ここで、位相可変機構に対する油圧は、通常、油圧源からカムシャフトの軸受部を介した後位相可変機構に供給されることになるが、カムシャフトの軸受部にはもともとカムシャフト潤滑用のカムシャフト用給油通路が形成されているため、カムシャフトの軸受部には、従来からあるカムシャフト用給油通路に加え、進角用給油通路及び遅角用給油通路の計３つの通路が並列に形成されることになる。
しかしながら、カムシャフトの軸受部に、進角用給油通路と遅角用給油通路とを単に並列に追加すると、カムシャフトの軸受部を構成するカムキャツプ等各部品の幅を長くする必要が生じ、それに伴ってエンジン全長が長くなり、エンジンが大型化するという問題が生じる。
【０００４】
本発明は、以上のような課題に勘案してなされたもので、その目的は、エンジンの大型化を抑制しつつ、進角用給油通路、遅角用給油通路を追加形成することが可能なエンジンの可変動弁装置を提供することにある。
【０００５】
【課題を解決するための手段】
前記目的を達成するため、本発明にあってはその解決手法として次のようにしてある。すなわち、本発明の第１の構成においては、吸気バルブまたは排気バルブを駆動するカムシャフトと、
該カムシャフトの一端側に設けられ、クランクシャフトの回転に同期して上記カムシャフトを回転させるカムシャフト駆動部材と、
上記カムシャフトとカムシャフト駆動部材との間の位相を変化させ、上記吸気バルブまたは排気バルブの開閉時期を進角側または遅角側に変更する油圧式の位相可変機構とを備え、
該位相可変機構は、上記カムシャフト駆動部材に連結されるケーシング部材と、
該ケーシング部材内に勘合され、上記カムシャフトに連結される回転部材と、上記ケーシング部材と上記回転部材との間に形成され、油圧の増大に伴って上記回転部材を吸気バルブまたは排気バルブの開閉時期が進角側になるように回転させる進角室と、
上記ケーシング部材と上記回転部材との間に形成され、油圧の増大に伴って上記回転部材を吸気バルブまたは排気バルブの開閉時期が遅角側になるように回転させる遅角室とを備えてなるエンジンの可変動弁装置において、
上記カムシャフトは、シリンダヘッド上部に設けられるカムホルダと、該カムホルダ上部に設けられるカムキャップとの間において軸支されるとともに、
上記位相可変機構における進角室と油圧源とを連通する進角用給油通路及び上記位相可変機構における遅角室と油圧源とを連通する遅角用給油通路が上記シリンダヘッド内に形成されており、かつ
該進角用給油通路及び遅角用給油通路の内、一方の通路が上記シリンダヘッドと上記カムホルダとの接合面に溝状に形成される一方、他方の通路が上記カムホルダと上記カムキャツプとの間の接合面に溝状に形成されるよう構成してある。本発明の第１の構成によれば、進角用給油通路と遅角用給油通路とが各々異なる接合面に溝状に形成されるため、同一面に形成される通路数の増加を抑制することができ、カムキャツプ等カムシャフトの軸受部を構成する部品の幅が長くなるのを抑えることができ、エンジン全長を抑えることができる。
【０００６】
また、本発明の第２の構成において、上記シリンダヘッドと上記カムホルダとの接合面または上記カムホルダと上記カムキャップとの接合面のいずれか一方の接合面には、上記カムシャフト潤滑用のカムシャフト用給油通路が溝状に形成されるよう構成してある。
本発明の第２の構成によれば、一つの接合面には、進角用給油通路と遅角用給油通路との内一方の通路と、カムシャフト用給油通路とが形成されるだけであって、全ての通路が同一面上に形成されることが抑制されるため、カムキャツプ等カムシャフトの軸受部を構成する部品の幅が長くなるのを抑えることができ、エンジン全長を抑えることができる。
【０００７】
また、本発明の第３の構成において、上記進角用給油通路及び遅角用給油通路は、上記油圧源と接続される主給油通路から分岐形成されており、上記主給油通路には、上記進角用給油通路及び遅角用給油通路の内いずれの通路と油圧源との連通状態を切換える油圧制御弁が備えられるよう構成してある。
本発明の第３の構成によれば、油圧制御弁によって油圧源に対する進角用給油通路及び遅角用給油通路の切換が行え、吸気バルブまたは排気バルブの開閉時期を変更することができる。
【０００８】
また、本発明の第４の構成において、上記カムシャフトは、吸気バルブ駆動用の吸気カムシャフトと、排気バルブ駆動用の排気カムシャフトとから構成されており、
該各カムシャフトには、各々上記位相可変機構が備えられるとともに、各位相可変機構に対して各々上記油圧制御弁が備えられたものであって、
上記位相可変機構における進角室は上記カムシャフトの回転方向に対して反回転方向に位置され、上記位相可変機構における遅角室は上記カムシャフトの回転方向に対して同回転方向に位置されるとともに、
上記排気カムシャフトに備えられた上記位相可変機構には、排気バルブの開閉時期が最進角位置になるよう上記回転部材を付勢する付勢部材が備えられており、
上記各油圧制御弁の内、上記排気カムシャフトに備えられた上記位相可変機構用の上記油圧制御弁を上記油圧源に近接させて配置するよう構成してある。
通常、位相可変機構は、エンジンが停止されて進角室、遅角室のいずれにも油圧が供給されなくなると、位相可変機構における回転部材がケーシング部材内のと遅角側に位置する突出部に接する位置まで回転させられるため、バルブの開閉時期は、最遅角位置とされる。
ここで、排気バルブが最遅角位置とされると排気バルブの閉時期が遅くなるため、吸、排気オーバーラップ期間が長くなり、内部ＥＧＲ量が増加するため、エンジン始動性が悪化するという問題がある。
そこで、排気バルブ用に位相可変機構を備えた場合、位相可変機構における回転部材を最進角に付勢するバネ等の付勢部材を設けることが行われている。
そして、付勢部材が備えられた位相可変機構を作動させる場合、その付勢部材の付勢力に抗して回転部材を駆動させるために油圧を高くすることが望まれる。本発明の第４の構成によれば、付勢部材が備えられる位相可変機構用の油圧制御弁を上記油圧源に近接させて配置されるため、付勢部材の付勢力に抗する高い油圧を供給することができ、付勢部材が備えられる位相可変機構による吸気バルブまたは排気バルブの開閉時期制御を正確に行うことができる。
【０００９】
また、本発明の第５の構成において、上記カムシャフトは、吸気バルブ駆動用の吸気カムシャフトと、排気バルブ駆動用の排気カムシャフトとから構成されるとともに、該各カムシャフトに各々上記位相可変機構が備えられており、
上記各カムシャフトに設けられた上記各位相可変機構に対する進角用給油通路又は遅角用給油通路がともに略同一線上に配置されるよう構成してある。
本発明の第５の構成によれば、各カムシャフト用に設けられた２つの進角用給油通路又は遅角用給油通路がともに略同一線上に配置されるため、カムキャップ等カムシャフトの軸受部を構成する部品の幅が長くなるのを抑えることができ、吸気カムシャフト及び排気カムシャフトに共に位相可変機構が備えられた場合であってもエンジン全長を抑えることができる。
【００１０】
【発明の効果】
本発明によれば、エンジンの大型化を抑制しつつ、進角用給油通路、遅角用給油通路を追加形成することができる。
【００１１】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて説明する。
図１は本発明の実施形態に係るシリンダヘッド平面図、図２は図１を紙面上左側から見たエンジン側面図（尚、可変位相機構の図示は省略している）、図３は図２のＡ−Ａ断面図、図４はロッカアーム平面図、図５はバルブスプリングを示す図である。
図１に示すように、シリンダヘッド１には、吸気カムシャフト２と排気カムシャフト３とが配設されており、その吸気カムシャフト２及び排気カムシャフト３の各一端には、各々位相可変機構４、５が備えられている。
【００１２】
吸気カムシャフト２、排気カムシャフト３は、図２に示されるように、シリンダヘッド１上に配設されるカムホルダ６とカムキャツプ７との間において軸支されている。
尚、８は、シリンダブロック９に配設されたオイルポンプである。
【００１３】
吸気カムシャフト２、排気カムシャフト３は、図３に示すように、ロッカーアーム１０、１１を介して２つの吸気バルブ１２、２つの排気バルブ１３を各々開閉駆動するよう構成されている。
また、吸気カムシャフト２は、図１に示すように、リフト量が異なる低速カム２ａと、高速カム２ｂ（低速カム２ａに対し、リフト量が大）とを各気筒毎に備えており、図４に示すように、吸気側のロッカアーム１０も低速カム２ａ用の低速用ロッカアーム１０ａと、高速カム２ｂ用の高速用ロッカアーム１０ｂとを備えている。
また、低速用ロッカーアーム１０ａにはロックピン１４が内臓される一方、高速用ロッカアーム１０ｂにはロックピン１４の挿入が可能なロックピン挿入孔１５が形成されている。
上記ロックピン１４は、油圧式の駆動装置（図示省略）によってロックピン挿入孔１５に対する挿入、非挿入状態が切換え制御されるように構成されており、例えば、エンジン回転数が設定回転数以下の時はロックピン１４をロックピン挿入孔に対し非挿入状態とし、エンジン回転数が設定回転数以上の時はロックピン１４をロックピン挿入孔１５に対し挿入状態となるよう切換えられる。
これによって、低回転時は低速カム２ａによって低速用ロッカーアーム１０ａが、高速カム２ｂによって高速用ロッカーアーム１０ｂが各々独立して駆動されるとともに、高回転時は高速カム２ｂによって低速用ロッカーアーム１０ａと高速用ロッカーアーム１０ｂとが同時に駆動される。
この時、図４に示すように、高速カム２ｂから高速用ロッカーアーム１０ｂに対する荷重入力点Ｗが吸気バルブ１２間センターＬに対し、所定量高速用ロッカアーム１０ｂ側にオフセットするよう設定されている。これは、低速用ロッカーアーム１０ａが、高速用ロッカーアーム１０ｂに対し小型化されており、重心が吸気バルブセンターＬよりも高速用ロッカーアーム１０ｂ側にずれているためであり、荷重入力点Ｗをこの重心に一致させることによって、高回転時、高速カム１０ｂにより低速用ロッカーアーム１０ａと高速用ロッカアーム１０ｂとを同時に駆動する際、低速用ロッカーアーム１０ａと高速用ロッカーアーム１０ｂとを均等な荷重バランスによって駆動することができる。
【００１４】
また、図３、５に示されるように、バルブシート１６はその座面が大径とされるとともに、バルブスプリング１７は、バルブシート１６の座面付近の一部のみ大径とされるよう構成されている。
これによって、軽量化によりバルブシート１６の剛性が低下した場合であっても、バルブシート１６におけるバルブスプリング１７の接触面積を大きく確保でき、面圧を低下させることができるため、バルブシート１６の耐久性、信頼性を確保することができる。
【００１５】
次に、位相可変機構４、５の詳細について説明する。
図６は位相可変機構４の断面図、図７は図６のＢ−Ｂ断面図、図８は図６のＣ−Ｃ断面図である。
尚、位相可変機構４、５は後述する付勢手段としてのスプリング部材Ｐを除いては同一構造であるため、以下吸気側の位相可変機構４について説明する。
位相可変機構４は、図６、７、８に示すように、中空とされて内面に複数の突出部１８ａを有するケーシング１８と、そのケーシング１８の蓋部材１９とを有し、これらのケーシング１８と、蓋部材１９とが複数のボルト２０によってカムプーリ２１に固定されている。
【００１６】
また、位相可変機構４は、座金２２を介してボルト２３により上記吸気カムシャフト２に固定された回転部材としてのロータ２４を有し、このロータ２４には、円筒状のボス部２４ａの外周から径方向に延びる４つの係合部２４ｂが備えられている。
この係合部２４ｂは、上記突出部１８ａと周方向に交互に配置されて８つの油圧室２５が形成されており、この内、各係合部２４ｂに対し吸気カムシャフト２の回転方向Ａに位置づけられた各４つの油圧室が遅角室２５ａとして構成され、各係合部２４ｂに対し吸気カムシャフトの反回転方向Ｂに位置づけられた各４つの油圧室を進角室２５ｂとして構成されている。
上記ロータ２４は、上記カムプーリ２１、ケーシング１８、蓋部材１９に対して、上記突出部２１ｂと係合部２４ｂとが当接するまで所定範囲（図７、８中Θじ示す範囲）内で相対回転可能とされ、吸気カムシャフト２のカムプーリ２１に対する位相角、言いかえれば、クランクシャフトに対する吸気カムシャフト２に対する位相角が変更可能され、これにより吸気バルブ１２の開閉時期が変更されるようになっている。
例えば、上記遅角室２５ａに油圧が供給されると、ロータ２４は、係合部２４ｂが突出部１８ａに係合するまで吸気カムシャフト２の回転方向Ａとは反対方向Ｂに回転され、図３、４中符合Ｘで示す最遅角位置とされる。また、上記進角室２５ｂに油圧が供給されると、ロータ２４は、係合部２４ｂが突出部１８ａに係合するまで吸気カムシャフト２の回転方向Ａと同方向に回転され、図３、４中符合Ｘ’で示す最進角位置とされる。
【００１７】
次に、吸気側の位相可変機構４に対する排気側の位相可変機構５の違いについて説明する。
排気側の位相可変機構５は、図１にも示すように、付勢手段としてのスプリング部材Ｐが配設されている。このスプリング部材Ｐは、ケーシング１８とロータ２４とに跨って固定されており、エンジン停止時、遅角室２５ａ、進角室２５ｂともに油圧が供給されなくなった際、ロータ２４位置を強制的に最進角位置Ｘに付勢するためのものである。これは、エンジン停止時、排気バルブ１３が最遅角位置とされ、吸、排気オーバーラップ期間が大きくなり、内部ＥＧＲが増大することによる始動性の悪化を抑制するためのものである。
【００１８】
次に、図２、図９〜１１に基づいて上記遅角室２５ａ及び進角室２５ｂに対する遅角用給油通路、進角用給油通路の構造について説明する。
図９は遅角用給油通路、進角用給油通路を摸式的に示す摸式図、図１０はカムホルダ６を下面側から見た平面図、図１１はカムキャップ７を下面側からみた平面図である。
図２、９に示すように、オイルポンプ８からの油圧は、主給油通路２６を介した後、まず排気用の位相可変機構５の油圧制御弁２７に供給される。
油圧制御弁２７に供給された油圧は、上記遅角室２５ａ、進角室２５ｂに各々切換えて供給されるように構成されている。
まず、油圧制御弁２７が遅角室２５ａに油圧が供給されるよう切換え制御された場合、シリンダヘッド１に形成された排気用第１遅角給油通路２８、図１０に示すシリンダヘッド１とカムホルダ６との接合面（カムホルダ６下面）に形成された溝状の排気用第２遅角給油通路２９、その排気用第２遅角給油通路２９から排気カムシャフト３に延びる排気用第３遅角給油通路３０及び図１１に示すカムホルダ６とカムキャツプ７との接合面（カムキャップ７下面）に形成された溝状の排気用第４遅角給油通路３１を介して上記遅角室２５ａに油圧が供給される。また、油圧制御弁２７が進角室２５ｂに油圧が供給されるよう切換え制御された場合、シリンダヘッド１に形成された排気用第１進角給油通路３２、図１０に示すシリンダヘッド１とカムホルダ６との接合面（カムホルダ６下面）に形成された溝状の排気用第２進角給油通路３３、その排気用第２進角給油通路３３から排気カムシャフト３に延びる排気用第３進角給油通路３４を介して上記進角室２５ｂに油圧が供給される。
また、排気用の位相可変機構５の油圧制御弁２７よりも下流側の主給油通路２６には、吸気用の位相可変機構４の油圧制御弁３５が配置されている。
油圧制御弁３５が遅角室２５ａに油圧が供給されるよう切換え制御された場合、
シリンダヘッド１に形成された吸気用第１遅角給油通路３６、図１１に示すカムホルダ６とカムキャップ７との接合面（カムキャップ７下面）に形成された溝状の吸気用第２遅角給油通路３７を介して上記遅角室２５ａに油圧が供給される。また、油圧制御弁３５が進角室２５ｂに油圧が供給されるよう切換え制御された場合、シリンダヘッド１に形成された吸気用第１進角給油通路３８、図１０に示すシリンダヘッド１とカムホルダ６との接合面（カムホルダ６下面）に形成された溝状の吸気用第２進角給油通路３９、その吸気用第２進角給油通路３９から吸気カムシャフト２に延びる吸気用第３進角給油通路４０を介して上記進角室２５ｂに油圧が供給される。
尚、上記主給油通路２６は、カムホルダ６とカムキャツプ７との接合面まで貫通するよう形成されており、その主給油通路２６は、図１１に示すように、各カムシャフト２、３の軸受部に潤滑油を供給するため、カムシャフト用通路２６ａ、２６ｂとに分岐形成されている。
【００１９】
また、図１１に示すように、排気用第４遅角給油通路３１及び吸気用第２遅角給油通路３７は、カムホルダ６の略中心付近から互いに相反する方向に延設されて排気用第４遅角給油通路３１と吸気用第２遅角給油通路３７とが略同一線上に配置されるとともに、カムシャフト用給油通路２６ａ、２６ｂも同一線上に配置され、カムホルダ６とカムキャップ７との接合面には、実質２つの給油通路が並列に形成されるよう構成されている。
【００２０】
以上のように、本実施形態によれば、進角用給油通路の一部を構成する排気用第２進角給油通路３３、吸気用第２進角給油通路３９が各々シリンダヘッド１とカムホルダ６との接合面に形成される一方、遅角用給油通路の一部を構成する排気用第４遅角給油通路３１、吸気用第２遅角給油通路３７が各々カムホルダ６とカムキャツプ７との接合面に形成されるよう構成されているため、進角用給油通路の一部と遅角用給油通路の一部とが各々異なる接合面に形成されて、同一面に形成される通路数の増加を抑制することができるため、カムホルダ６、カムキャップ７の幅が長くなるのを抑えることができ、エンジン全長を抑えることができる。
また、カムホルダ６とカムキャップ７との接合面において、カムホルダ６の中心付近から排気用第４遅角給油通路３１と吸気用第２遅角給油通路３７とが互いに相反する方向に延設され、両通路３１、３７が略同一線上に位置するよう配置されるとともに、カムシャフト用給油通路２６ａ、２６ｂも略同一線上に位置するよう配置されるため、一つの接合面において、実質２つの通路を形成するだけのカムホルダ６の幅を確保しておけばよく、吸気カムシャフト２及び排気カムシャフト３に共に位相可変機構４、５が備えられた場合であってもカムホルダ６の幅が長くなるのを抑えることができ、エンジン全長を抑えることができる。
また、排気用の位相可変機構５の油圧制御弁２７は、油圧源としてのオイルポンプ８に近接させて配置されるため、排気用の位相可変機構５に高い油圧を供給することができ、スプリング部材Ｐの付勢力に抗する高い油圧により排気用の位相可変機構５によるバルブタイミングの変更を正確に行うことができる。
【００２１】
尚、本実施形態では、遅角用給油通路の一部をカムホルダ６とカムキャツプ７との接合面に、進角用給油通路の一部をカムホルダ６とシリンダヘッド１との接合面に形成する例を示したが、逆に遅角用給油通路の一部をカムホルダ６とシリンダヘッド１との接合面に、進角用給油通路の一部をカムホルダ６とカムキャツプ７との接合面に形成するようにしてもよい。
また、本実施形態では、カムホルダ６とカムキャツプ７との接合面に形成される遅角用通路の一部はカムキャツプ７下面に、カムホルダ６とシリンダヘッド１との接合面に形成される進角用通路の一部はカムホルダ６下面に、各々形成する例を示したが、遅角用通路の一部をカムホルダ６側の上面側に、進角用通路の一部をシリンダヘッド１側の上面側に形成するようにしてもよい。
また、本実施形態では、位相可変機構を吸気カムシャフト２と、排気カムシャフト３との両方に備える例を示したが、いずれか一方のみ備えるエンジンに適用させるようにしてもよい。
【図面の簡単な説明】
【図１】本実施形態に係るシリンダヘッド平面図。
【図２】本実施形態に係るエンジン側面図。
【図３】図２のＡ−Ａ断面図。
【図４】ロッカーアーム平面図。
【図５】バルブスプリングを示す図。
【図６】位相可変機構４の断面図。
【図７】図６のＢ−Ｂ断面図。
【図８】図６のＣ−Ｃ断面図。
【図９】図９は遅角用給油通路、進角用給油通路を摸式的に示す摸式図。
【図１０】カムホルダ６を下面側から見た平面図。
【図１１】カムキャップ７を下面側からみた平面図。
【符号の説明】
１：シリンダヘッド
２：吸気カムシャフト
３：排気カムシャフト
４、５：位相可変機構
６：カムホルダ
７：カムキャップ
８：オイルポンプ（油圧源）
１２：吸気バルブ
１３：排気バルブ
１８：ケーシング（ケーシング部材）
２１：カムプーリ（カムシャフト駆動部材）
２４：ロータ（回転部材）
２５ａ：遅角室
２５ｂ：進角室
２６ａ、２６ｂ：カムシャフト用給油通路
２７、３５：油圧制御弁
２８：排気用第１遅角給油通路（遅角用給油通路）
２９：排気用第２遅角給油通路（遅角用給油通路）
３０：排気用第３遅角給油通路（遅角用給油通路）
３１：排気用第４遅角給油通路（遅角用給油通路）
３２：排気用第１進角給油通路（進角用給油通路）
３３：排気用第２進角給油通路（進角用給油通路）
３４：排気用第３進角給油通路（進角用給油通路）
３６：吸気用第１遅角給油通路（遅角用給油通路）
３７：吸気用第２遅角給油通路（遅角用給油通路）
３８：吸気用第１進角給油通路（進角用給油通路）
３９：吸気用第２進角給油通路（進角用給油通路）
４０：吸気用第３進角給油通路（進角用給油通路）
Ｐ：スプリング部材（付勢部材）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a variable valve operating device for an engine, and more particularly, to a variable valve operating device for an engine having a hydraulic phase variable mechanism.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a valve timing control device for this type of engine, it is known that a hydraulic phase variable mechanism is provided at one end of a camshaft to change the phase between a sprocket or a timing pulley and the camshaft.
For example, as disclosed in Japanese Patent Application Laid-Open No. 9-195805, the variable phase mechanism includes a casing integrally connected to a cam pulley at one end of a camshaft, and a cam which is fitted in the casing to form a cam. And a rotor integrally connected to the shaft. The casing is formed in a hollow cylindrical shape, and four protruding portions extending toward the center of the hollow cylinder are formed on the inner surface of the hollow cylinder. The rotor has a radially outward direction from the outer periphery of the cylindrical boss portion. Are formed. The four projecting portions formed on the casing and the four vanes formed on the rotor are alternately arranged in the circumferential direction to form eight pressure receiving chambers. Of the eight pressure receiving chambers, each vane of the rotor is provided. In contrast, the four pressure receiving chambers located on the rotation side of the camshaft are configured as retard chambers, while the four pressure receiving chambers located on the opposite side of the retard chamber are configured as advance chambers.
In such a variable phase mechanism, when the retard chamber and the hydraulic pressure source communicate with each other, the oil pressure in the retard chamber is increased, and the rotor is rotated on the opposite side to the rotation of the camshaft with respect to the casing. While the valve timing can be changed to the retard side, when the advance chamber communicates with the hydraulic pressure source, the oil pressure in the advance chamber is increased, and the rotor is rotated relative to the casing to the side where the camshaft rotates. Thus, the valve timing can be changed to the advance side.
[0003]
[Problems to be solved by the invention]
By the way, when a hydraulic phase variable mechanism is provided as in the above-described prior art, an advance oil supply passage communicating the advance chamber with the hydraulic source, and a retard oil passage communicating the retard chamber with the hydraulic source are provided. It is necessary to add an oil supply passage.
Here, the hydraulic pressure for the variable phase mechanism is normally supplied from the hydraulic pressure source to the variable phase mechanism via the bearing portion of the camshaft, but the camshaft bearing originally has a camshaft for camshaft lubrication. Since the oil supply passage for the shaft is formed, a total of three passages, an advance oil supply passage and a retard oil supply passage, are formed in parallel with the conventional camshaft oil supply passage in the bearing portion of the camshaft. Will be done.
However, simply adding an advancing oil supply passage and a retarding oil supply passage to the camshaft bearing portion in parallel requires the width of each component, such as a cam cap, that constitutes the camshaft bearing portion to be increased. Along with this, there arises a problem that the total length of the engine becomes longer and the size of the engine becomes larger.
[0004]
The present invention has been made in view of the above-described problems, and an object of the present invention is to make it possible to additionally form an advance oil supply passage and a retard oil supply passage while suppressing an increase in the size of an engine. An object of the present invention is to provide a variable valve operating device for an engine.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides the following as a solution. That is, in the first configuration of the present invention, a camshaft that drives an intake valve or an exhaust valve;
A camshaft drive member provided on one end side of the camshaft and rotating the camshaft in synchronization with rotation of a crankshaft;
A hydraulic phase variable mechanism that changes the phase between the camshaft and the camshaft drive member, and changes the opening / closing timing of the intake valve or the exhaust valve to an advanced side or a retarded side,
A casing member connected to the camshaft driving member;
A rotating member fitted into the casing member and connected to the camshaft; and a rotating member formed between the casing member and the rotating member, which opens and closes an intake valve or an exhaust valve with an increase in hydraulic pressure. An advance chamber that rotates so that the time is on the advance side,
A retard chamber formed between the casing member and the rotating member, for rotating the rotating member such that the opening / closing timing of an intake valve or an exhaust valve is retarded with an increase in hydraulic pressure. In engine variable valve gear,
The camshaft is supported between a cam holder provided on an upper portion of a cylinder head and a cam cap provided on an upper portion of the cam holder,
An advance oil supply passage communicating the advance chamber and the hydraulic power source in the variable phase mechanism and a retard oil supply passage communicating the retard chamber and the hydraulic source in the variable phase mechanism are formed in the cylinder head. One of the advancing oil supply passage and the retarding oil supply passage is formed in a groove shape on a joint surface between the cylinder head and the cam holder, and the other passage is formed between the cam holder and the cam cap. Is formed in the shape of a groove on the joint surface between them. According to the first configuration of the present invention, since the advancing oil supply passage and the retarding oil supply passage are formed in the form of grooves on different joining surfaces, an increase in the number of passages formed on the same surface is suppressed. Therefore, it is possible to suppress an increase in the width of a component constituting a bearing portion of a camshaft such as a cam cap, thereby suppressing an overall engine length.
[0006]
Further, in the second configuration of the present invention, the camshaft for lubricating the camshaft may be provided on one of a joint surface between the cylinder head and the cam holder or a joint surface between the cam holder and the cam cap. The fuel supply passage is formed in a groove shape.
According to the second configuration of the present invention, only one of the advance oil supply passage and the retard oil supply passage and the camshaft oil supply passage are formed on one joint surface. Therefore, since all the passages are suppressed from being formed on the same plane, it is possible to suppress an increase in the width of a component constituting a bearing portion of a camshaft such as a cam cap, and to suppress an overall engine length. .
[0007]
Further, in the third configuration of the present invention, the advance oil supply passage and the retard oil supply passage are formed by branching from a main oil supply passage connected to the hydraulic pressure source. A hydraulic control valve for switching a communication state between any one of the advance oil supply passage and the retard oil supply passage and the hydraulic power source is provided.
According to the third configuration of the present invention, it is possible to switch between the advance oil supply passage and the retard oil supply passage for the hydraulic pressure source by the hydraulic control valve, and to change the opening / closing timing of the intake valve or the exhaust valve.
[0008]
Further, in the fourth configuration of the present invention, the camshaft includes an intake camshaft for driving an intake valve and an exhaust camshaft for driving an exhaust valve.
Each of the camshafts is provided with the variable phase mechanism, and the hydraulic control valve is provided for each variable phase mechanism,
The advance chamber in the variable phase mechanism is located in a direction opposite to the rotation direction of the camshaft, and the retard chamber in the variable phase mechanism is located in the same rotation direction as the rotation direction of the camshaft. With
The variable phase mechanism provided in the exhaust camshaft includes an urging member that urges the rotating member so that the opening and closing timing of the exhaust valve is at the most advanced position.
Among the hydraulic control valves, the hydraulic control valve for the variable phase mechanism provided on the exhaust camshaft is arranged close to the hydraulic power source.
Normally, when the engine is stopped and the hydraulic pressure is not supplied to both the advance chamber and the retard chamber, the rotating member of the phase variable mechanism is located at the retard side with respect to the rotating member in the casing member. , The valve is opened and closed at the most retarded position.
Here, when the exhaust valve is set to the most retarded position, the closing timing of the exhaust valve is delayed, so that the intake and exhaust overlap periods are prolonged, and the internal EGR amount is increased, thereby deteriorating the engine startability. There is.
Therefore, when a variable phase mechanism is provided for the exhaust valve, an urging member such as a spring for urging the rotating member of the variable phase mechanism to the most advanced angle has been provided.
When operating the variable phase mechanism provided with the urging member, it is desirable to increase the hydraulic pressure in order to drive the rotating member against the urging force of the urging member. According to the fourth configuration of the present invention, since the hydraulic control valve for the variable phase mechanism provided with the urging member is disposed close to the hydraulic pressure source, a high hydraulic pressure against the urging force of the urging member is provided. The opening / closing timing of the intake valve or the exhaust valve can be accurately controlled by the variable phase mechanism provided with the biasing member.
[0009]
Further, in the fifth configuration of the present invention, the camshaft includes an intake camshaft for driving an intake valve and an exhaust camshaft for driving an exhaust valve, and each of the camshafts has a variable phase. Mechanism is provided,
The advance oil supply passage or the retard oil supply passage for each of the phase variable mechanisms provided in each of the camshafts is arranged on substantially the same line.
According to the fifth configuration of the present invention, the two advancing oil supply passages or the retarding oil supply passages provided for the respective camshafts are both disposed substantially on the same line, so that camshaft bearings such as cam caps are provided. It is possible to suppress an increase in the width of the components constituting the portion, and to suppress the overall length of the engine even when both the intake camshaft and the exhaust camshaft are provided with a phase variable mechanism.
[0010]
【The invention's effect】
According to the present invention, it is possible to additionally form an advance oil supply passage and a retard oil supply passage while suppressing an increase in the size of the engine.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view of a cylinder head according to an embodiment of the present invention, FIG. 2 is a side view of an engine when FIG. 1 is viewed from the left side on the paper (note that a variable phase mechanism is not shown), and FIG. FIG. 4 is a plan view of a rocker arm, and FIG. 5 is a view showing a valve spring.
As shown in FIG. 1, an intake camshaft 2 and an exhaust camshaft 3 are disposed in a cylinder head 1, and one end of each of the intake camshaft 2 and the exhaust camshaft 3 is provided with a phase variable mechanism. 4 and 5 are provided.
[0012]
As shown in FIG. 2, the intake camshaft 2 and the exhaust camshaft 3 are supported between a cam holder 6 provided on the cylinder head 1 and a cam cap 7.
Reference numeral 8 denotes an oil pump provided on the cylinder block 9.
[0013]
As shown in FIG. 3, the intake camshaft 2 and the exhaust camshaft 3 are configured to open and close two intake valves 12 and two exhaust valves 13 via rocker arms 10 and 11, respectively.
As shown in FIG. 1, the intake camshaft 2 includes a low-speed cam 2a having a different lift amount and a high-speed cam 2b (a lift amount is larger than the low-speed cam 2a) for each cylinder. As shown in FIG. 4, the rocker arm 10 on the intake side also includes a low-speed rocker arm 10a for the low-speed cam 2a and a high-speed rocker arm 10b for the high-speed cam 2b.
The low-speed rocker arm 10a has a built-in lock pin 14, while the high-speed rocker arm 10b has a lock pin insertion hole 15 through which the lock pin 14 can be inserted.
The lock pin 14 is configured so that the state of insertion and non-insertion into the lock pin insertion hole 15 is controlled to be switched by a hydraulic drive device (not shown). For example, the engine speed is equal to or less than a set speed. At this time, the lock pin 14 is set in the non-insertion state into the lock pin insertion hole, and when the engine speed is equal to or higher than the set rotation speed, the lock pin 14 is switched to the insertion state into the lock pin insertion hole 15.
Thus, the low-speed cam 2a drives the low-speed rocker arm 10a by the low-speed cam 2a, and the high-speed cam 2b independently drives the high-speed rocker arm 10b. And the high-speed rocker arm 10b are simultaneously driven.
At this time, as shown in FIG. 4, the load input point W from the high-speed cam 2b to the high-speed rocker arm 10b is set to be offset from the center L between the intake valves 12 by a predetermined amount toward the high-speed rocker arm 10b. This is because the low-speed rocker arm 10a is smaller than the high-speed rocker arm 10b, and the center of gravity is shifted toward the high-speed rocker arm 10b from the intake valve center L. When the low-speed rocker arm 10a and the high-speed rocker arm 10b are simultaneously driven by the high-speed cam 10b during high rotation, the low-speed rocker arm 10a and the high-speed rocker arm 10b are evenly balanced by matching the center of gravity with the high-speed cam 10b. Can be driven by
[0014]
Also, as shown in FIGS. 3 and 5, the valve seat 16 is configured such that its seating surface has a large diameter, and the valve spring 17 has a large diameter only in a part near the seating surface of the valve seat 16. Have been.
As a result, even when the rigidity of the valve seat 16 is reduced due to weight reduction, a large contact area of the valve spring 17 with the valve seat 16 can be ensured, and the surface pressure can be reduced. And reliability can be ensured.
[0015]
Next, details of the phase variable mechanisms 4 and 5 will be described.
6 is a sectional view of the phase variable mechanism 4, FIG. 7 is a sectional view taken along line BB of FIG. 6, and FIG. 8 is a sectional view taken along line CC of FIG.
Since the phase variable mechanisms 4 and 5 have the same structure except for a spring member P as an urging means described later, the phase variable mechanism 4 on the intake side will be described below.
As shown in FIGS. 6, 7, and 8, the variable phase mechanism 4 includes a casing 18 that is hollow and has a plurality of protrusions 18a on the inner surface, and a lid member 19 of the casing 18. And the lid member 19 are fixed to the cam pulley 21 by a plurality of bolts 20.
[0016]
The variable phase mechanism 4 also has a rotor 24 as a rotating member fixed to the intake camshaft 2 by bolts 23 via washers 22. The rotor 24 is provided with an outer periphery of a cylindrical boss 24a. Four engagement portions 24b extending in the radial direction are provided.
The engaging portions 24b are alternately arranged in the circumferential direction with the projecting portions 18a to form eight hydraulic chambers 25. Of these, eight hydraulic chambers 25 are formed with respect to each of the engaging portions 24b in the rotation direction A of the intake camshaft 2. Each of the four hydraulic chambers positioned is configured as a retard chamber 25a, and each of the four hydraulic chambers positioned in the anti-rotation direction B of the intake camshaft with respect to each engagement portion 24b is configured as an advance chamber 25b. I have.
The rotor 24 rotates relative to the cam pulley 21, the casing 18, and the cover member 19 within a predetermined range (the range shown in FIGS. 7 and 8) until the protrusion 21b and the engagement portion 24b come into contact with each other. It is possible to change the phase angle of the intake camshaft 2 with respect to the cam pulley 21, in other words, the phase angle of the intake camshaft 2 with respect to the crankshaft, thereby changing the opening / closing timing of the intake valve 12. I have.
For example, when hydraulic pressure is supplied to the retard chamber 25a, the rotor 24 is rotated in the direction B opposite to the rotation direction A of the intake camshaft 2 until the engagement portion 24b engages with the protrusion 18a. It is the most retarded position indicated by the symbol X in the middle of 3, 4. When hydraulic pressure is supplied to the advance chamber 25b, the rotor 24 is rotated in the same direction as the rotation direction A of the intake camshaft 2 until the engagement portion 24b engages with the protrusion 18a. 4 is the most advanced position indicated by the symbol X '.
[0017]
Next, the difference between the intake-side variable phase mechanism 4 and the exhaust-side variable phase mechanism 5 will be described.
As shown in FIG. 1, the variable phase mechanism 5 on the exhaust side is provided with a spring member P as urging means. The spring member P is fixed across the casing 18 and the rotor 24. Forcibly resetting the position of the rotor 24 when the engine stops and no oil pressure is supplied to both the retard chamber 25a and the advance chamber 25b. This is for biasing to the advanced position X. This is for suppressing the deterioration of the startability due to the exhaust valve 13 being at the most retarded position when the engine is stopped, the intake and exhaust overlap periods being increased, and the internal EGR being increased.
[0018]
Next, the structure of the retard oil supply passage and the advance oil supply passage for the retard chamber 25a and the advance chamber 25b will be described with reference to FIGS.
FIG. 9 is a schematic view schematically showing a retarding oil supply passage and an advance oiling passage, FIG. 10 is a plan view of the cam holder 6 as viewed from below, and FIG. 11 is a plan view of the cam cap 7 as viewed from below. FIG.
As shown in FIGS. 2 and 9, the oil pressure from the oil pump 8 is supplied to the oil pressure control valve 27 of the variable phase mechanism 5 for exhaust after passing through the main oil supply passage 26.
The hydraulic pressure supplied to the hydraulic control valve 27 is configured to be switched and supplied to the retard chamber 25a and the advance chamber 25b, respectively.
First, when the hydraulic pressure control valve 27 is switched to supply hydraulic pressure to the retard chamber 25a, a first retard oil supply passage 28 for exhaust formed in the cylinder head 1, the cylinder head 1 and the cam holder shown in FIG. 6, a groove-shaped exhaust second retard oil supply passage 29 formed on the joint surface with the cam holder 6 (the lower surface of the cam holder 6), and an exhaust third retard oil extending from the exhaust second retard oil supply passage 29 to the exhaust camshaft 3. Hydraulic pressure is applied to the retard chamber 25a through the oil supply passage 30 and a groove-shaped fourth exhaust retard oil supply passage 31 for exhaust formed in the joint surface (the lower surface of the cam cap 7) of the cam holder 6 and the cam cap 7 shown in FIG. Supplied. When the hydraulic control valve 27 is switched to supply hydraulic pressure to the advance chamber 25b, the first advance oil supply passage 32 for exhaust formed in the cylinder head 1, the cylinder head 1 and the cam holder shown in FIG. 6, a groove-shaped exhaust second advanced oil supply passage 33 formed on the joint surface with the cam holder 6 (the lower surface of the cam holder 6), and an exhaust third advanced angle extended from the exhaust second advanced oil supply passage 33 to the exhaust camshaft 3. Oil pressure is supplied to the advance chamber 25b via the oil supply passage 34.
The hydraulic control valve 35 of the intake variable phase mechanism 4 is disposed in the main oil supply passage 26 downstream of the hydraulic control valve 27 of the variable exhaust phase mechanism 5.
When the hydraulic control valve 35 is switched to supply the hydraulic pressure to the retard chamber 25a,
A first intake retarding oil supply passage 36 formed in the cylinder head 1, a groove-shaped second intake retardation formed on a joint surface (the lower surface of the cam cap 7) between the cam holder 6 and the cam cap 7 shown in FIG. 11. Oil pressure is supplied to the retard chamber 25a via the oil supply passage 37. When the hydraulic control valve 35 is switched to supply hydraulic pressure to the advance chamber 25b, the first advance oil supply passage 38 for intake formed in the cylinder head 1, the cylinder head 1 and the cam holder shown in FIG. 6, a groove-shaped intake second advanced oil supply passage 39 formed on the joint surface with the cam holder 6 (the lower surface of the cam holder 6), and an intake third advanced angle extended from the intake second advanced oil supply passage 39 to the intake camshaft 2. Hydraulic pressure is supplied to the advance chamber 25b through the oil supply passage 40.
The main oil supply passage 26 is formed so as to penetrate to the joint surface between the cam holder 6 and the cam cap 7, and the main oil supply passage 26 is, as shown in FIG. In order to supply the lubricating oil to the camshaft, it is branched to the camshaft passages 26a and 26b.
[0019]
As shown in FIG. 11, the exhaust fourth retard oil supply passage 31 and the intake second retard oil supply passage 37 extend from substantially near the center of the cam holder 6 in directions opposite to each other. The retard oil supply passage 31 and the intake second retard oil supply passage 37 are arranged substantially on the same line, and the camshaft oil supply passages 26a, 26b are also arranged on the same line, so that the cam holder 6 and the cam cap 7 are joined. The surface is configured such that substantially two oil supply passages are formed in parallel.
[0020]
As described above, according to the present embodiment, the second advance angle oil supply passage 33 for exhaust and the second advance angle oil supply passage 39 for intake constitute a part of the advance angle oil supply passage, respectively. The fourth exhaust retarding oil supply passage 31 for exhaust and the second retarding oil supply passage 37 for intake which constitute a part of the retarding oil supply passage are joined to the cam holder 6 and the cam cap 7, respectively. Since a part of the advancing oil supply passage and a part of the retarding oil supply passage are formed on different joining surfaces, the number of passages formed on the same surface increases. Therefore, the width of the cam holder 6 and the cam cap 7 can be prevented from becoming longer, and the overall length of the engine can be reduced.
Further, on the joint surface between the cam holder 6 and the cam cap 7, a fourth exhaust retarding oil supply passage 31 for exhaust and a second retarding oil supply passage 37 for intake extend from near the center of the cam holder 6 in directions opposite to each other, The two passages 31, 37 are arranged so as to be located substantially on the same line, and the camshaft oil supply passages 26a, 26b are also arranged so as to be located substantially on the same line. The width of the cam holder 6 only needs to be ensured, and even if the intake camshaft 2 and the exhaust camshaft 3 are both provided with the phase variable mechanisms 4, 5, the width of the cam holder 6 becomes long. And the overall length of the engine can be reduced.
Further, since the hydraulic control valve 27 of the variable phase mechanism for exhaust 5 is disposed close to the oil pump 8 as a hydraulic source, a high hydraulic pressure can be supplied to the variable phase mechanism for exhaust 5 and the spring The valve timing can be accurately changed by the exhaust phase variable mechanism 5 by the high oil pressure against the urging force of the member P.
[0021]
In this embodiment, an example in which a part of the retarding oil supply passage is formed on the joint surface between the cam holder 6 and the cam cap 7 and a part of the advance oil supply passage is formed on the joint surface between the cam holder 6 and the cylinder head 1. However, conversely, a part of the retarding oil supply passage is formed on the joint surface between the cam holder 6 and the cylinder head 1 and a part of the advance oil supply passage is formed on the joint surface between the cam holder 6 and the cam cap 7. It may be.
Further, in this embodiment, a part of the retard passage formed on the joint surface between the cam holder 6 and the cam cap 7 is formed on the lower surface of the cam cap 7 and on the advance surface formed on the joint surface between the cam holder 6 and the cylinder head 1. An example in which a part of the passage is formed on the lower surface of the cam holder 6 has been shown. May be formed.
Further, in the present embodiment, an example in which the variable phase mechanism is provided in both the intake camshaft 2 and the exhaust camshaft 3 has been described, but the present invention may be applied to an engine having only one of them.
[Brief description of the drawings]
FIG. 1 is a plan view of a cylinder head according to an embodiment.
FIG. 2 is a side view of the engine according to the embodiment.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is a plan view of a rocker arm.
FIG. 5 is a view showing a valve spring.
FIG. 6 is a cross-sectional view of the variable phase mechanism 4.
FIG. 7 is a sectional view taken along line BB of FIG. 6;
FIG. 8 is a sectional view taken along the line CC of FIG. 6;
FIG. 9 is a schematic view schematically showing a retard angle oil supply passage and an advance angle oil supply passage.
FIG. 10 is a plan view of the cam holder 6 as viewed from a lower surface side.
FIG. 11 is a plan view of the cam cap 7 as viewed from below.
[Explanation of symbols]
1: Cylinder head 2: Intake camshaft 3: Exhaust camshaft 4, 5: Variable phase mechanism 6: Cam holder 7: Cam cap 8: Oil pump (oil pressure source)
12: intake valve 13: exhaust valve 18: casing (casing member)
21: Cam pulley (cam shaft drive member)
24: Rotor (rotating member)
25a: retard chamber 25b: advance chambers 26a, 26b: camshaft oil supply passages 27, 35: hydraulic control valve 28: exhaust first retard oil supply passage (retard oil supply passage)
29: Exhaust second retard lubrication passage (retard lubrication passage)
30: Exhaust third retard lubrication passage (retard lubrication passage)
31: Exhaust fourth retard lubrication passage (retard lubrication passage)
32: First advance oil supply passage for exhaust (advance oil supply passage)
33: Second advance oil supply passage for exhaust (advance oil supply passage)
34: Exhaust third advance oil supply passage (advance oil supply passage)
36: Intake first retard lubrication passage (retard lubrication passage)
37: second intake retard oil supply passage (retard oil supply passage)
38: First advance oil supply passage for intake (advance oil supply passage)
39: intake second advance oil supply passage (advance oil supply passage)
40: Third advance oil supply passage for intake (advance oil supply passage)
P: Spring member (biasing member)

Claims

A camshaft that drives an intake or exhaust valve,
A camshaft drive member provided on one end side of the camshaft and rotating the camshaft in synchronization with rotation of a crankshaft;
A hydraulic phase variable mechanism that changes the phase between the camshaft and the camshaft drive member, and changes the opening / closing timing of the intake valve or the exhaust valve to an advanced side or a retarded side,
A casing member connected to the camshaft drive member and integrally rotating with the camshaft drive member;
A rotating member fitted into the casing member and connected to the camshaft to rotate integrally with the camshaft;
An advance chamber formed between the casing member and the rotating member, and rotating the rotating member such that the opening / closing timing of an intake valve or an exhaust valve is advanced with an increase in hydraulic pressure,
A retard chamber formed between the casing member and the rotating member, for rotating the rotating member such that the opening / closing timing of an intake valve or an exhaust valve is retarded with an increase in hydraulic pressure. In engine variable valve gear,
The camshaft is supported between a cam holder provided on an upper portion of a cylinder head and a cam cap provided on an upper portion of the cam holder,
The cylinder head is formed with an advance oil supply passage communicating the advance chamber and the hydraulic pressure source in the variable phase mechanism, and a retard oil supply passage communicating the retard chamber and the hydraulic source in the variable phase mechanism. A part of one of the advancing oil supply passage and the retarding oil supply passage is formed in a groove shape on a joint surface between the cylinder head and the cam holder, and a part of the other passage is formed. A variable valve gear for an engine, wherein the groove is formed on a joint surface between the cam holder and the cam cap.

A camshaft lubrication passage for lubricating the camshaft is formed in a groove on one of the joining surface between the cylinder head and the cam holder or the joining surface between the cam holder and the cam cap. 2. The variable valve operating device for an engine according to claim 1, wherein:

The advance oil supply passage and the retard oil supply passage are branched from a main oil supply passage connected to the hydraulic pressure source, and the main oil supply passage includes the advance oil supply passage and the retard oil supply passage. 3. The variable valve train for an engine according to claim 1, further comprising a hydraulic control valve for switching a communication state between any one of the passages and the hydraulic power source.

The camshaft includes an intake camshaft for driving an intake valve, and an exhaust camshaft for driving an exhaust valve,
Each of the camshafts is provided with the variable phase mechanism, and the hydraulic control valve is provided for each variable phase mechanism,
The advance chamber in the variable phase mechanism is located in a direction opposite to the rotation direction of the camshaft, and the retard chamber in the variable phase mechanism is located in the same rotation direction as the rotation direction of the camshaft. With
The variable phase mechanism provided in the exhaust camshaft includes an urging member that urges the rotating member so that the opening and closing timing of the exhaust valve is at the most advanced position.
4. The variable operation of the engine according to claim 3, wherein, among the hydraulic control valves, the hydraulic control valve for the variable phase mechanism provided on the exhaust camshaft is arranged close to the hydraulic power source. Valve device.

The camshaft includes an intake camshaft for driving an intake valve, and an exhaust camshaft for driving an exhaust valve, and each of the camshafts includes the phase variable member,
The engine according to any one of claims 1 to 4, wherein an advance oil supply passage or a retard oil supply passage for each of the phase variable mechanisms provided on each of the camshafts is arranged substantially on the same line. Variable valve gear.