JP2004278710A

JP2004278710A - Metal gasket for cylinder head

Info

Publication number: JP2004278710A
Application number: JP2003072547A
Authority: JP
Inventors: Yoshiaki Hamada; 義明浜田; Takashi Yajima; 崇矢島; Yasunori Murakami; 康則村上; Takashi Katsurai; 隆桂井; Katsumune Tabata; 勝宗田畑
Original assignee: Honda Motor Co Ltd; Nippon Leakless Corp
Current assignee: Honda Motor Co Ltd; Nippon Leakless Corp
Priority date: 2003-03-17
Filing date: 2003-03-17
Publication date: 2004-10-07

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive metal gasket with high degree of freedom in controlling the height of a step. <P>SOLUTION: The metal gasket for a cylinder head comprises cylinder holes 2a that are made of metal sheets and formed correspondingly to respective cylinder bores of the cylinder block, an annular bead 2b of an angle cross sectional shape formed around each cylinder hole, a refrigerant hole 2c formed in the outside periphery of each annular bead, and an outer peripheral bead 2d of a one-side slope cross sectional shape formed at a position entirely surrounding the annular beads and the refrigerant holes. The metal gasket for the cylinder head further comprises two substrates 2 stacked mutually, a sub plate 3 that is made of a metal sheet and inserted between two substrates, a metal foil layer 5 made of metal foil that is adhered to at least one surface of the sub plate and extends from a position radially inside of the annular beads to a position radially outside of it so as to overlap on each annular bead of the substrate and face the top of the annular bead, and an adhesive layer 7 made of an adhesive for adhering the metal foil to the sub plate while being at least pressurized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、内燃機関のシリンダーブロックとシリンダーヘッドとの間に介挿されるシリンダーヘッド用メタルガスケットに関するものである。
【０００２】
【従来の技術】
この種のメタルガスケットとしては、例えば、それぞれ金属板からなる二枚の基板と、それらの基板より薄い板厚の金属板からなり、それらの基板間に介挿される副板とを具え、前記各基板が、内燃機関のシリンダーブロックの各シリンダーボアに対応して形成されたシリンダー孔と、各シリンダー孔の周囲に形成された山形断面形状の環状ビードと、前記内燃機関のシリンダーブロックの冷却水ジャケットおよびシリンダーヘッドの冷却水孔に対応して前記各環状ビードの外側周辺部に形成された冷却水孔とを有し、前記副板が、基板と同様のシリンダー穴と冷却水穴とを有するメタルガスケットが知られており、かかるメタルガスケットにおいては、その副板に、基板の各シリンダー孔の周囲の環状ビードと重なるシリンダー孔周辺部をそれより外側の外方部よりも厚くする段差構造を設けて、基板の環状ビードの線圧を上昇させることで、シリンダー内の燃焼ガスに対するシール性能を向上させる場合がある。
【０００３】
上記段差構造としては従来、例えば、図９に示すように、それぞれ鋼板（ＳＵＳ３０１Ｈ０．２ｔ等）からなる二枚の基板２間に介挿される副板３を、基板２の各シリンダー孔２ａの周囲の環状ビード２ｂと重なるシリンダー孔周辺部３ａとそれより外側に位置する外方部３ｂとで互いに異なる板厚の薄鋼板（ＳＵＳ３０１Ｈ０．２ｔ，０．３ｔ等）で構成して所要の段差になるようにし、それらシリンダー孔周辺部３ａと外方部３ｂとをレーザー溶接で結合した段差構造Ｓ１が知られている（例えば、特許文献１参照）。なお、図中符号１はメタルガスケット、ＬＷはレーザー溶接部を示す。
【０００４】
また例えば図１０に示すように、それぞれ鋼板からなる二枚の基板２間に介挿される単一板厚の薄鋼板（ＳＵＳ３０１Ｈ０．１ｔ等）からなる副板３の、基板２の各シリンダー孔２ａの周囲の環状ビード２ｂと重なるシリンダー孔周辺部３ａにこれも薄鋼板（ＳＵＳ３０１Ｈ０．１ｔ等）からなるシム板４を重ねて所要の段差になるようにし、それら副板３とシム板４とをレーザー溶接で結合した段差構造Ｓ２も知られている（例えば、特許文献２参照）。
【０００５】
さらに、例えば図１１に示すように、それぞれ鋼板からなる二枚の基板２間に介挿される単一板厚の薄鋼板（ＳＵＳ３０１Ｈ０．０５ｔ等）からなる副板３の、基板２の各シリンダー孔２ａの周囲の環状ビード２ｂと重なるシリンダー孔周辺部３ａに折り返し曲げ加工により折り重ね部３ｃを形成して所要の段差になるようにした段差構造Ｓ３も知られている（例えば、特許文献３参照）。
【０００６】
【特許文献１】
特開平７−２４３５３１号公報、第３図
【特許文献２】
特開平１０−６１７７２号公報
【特許文献３】
特開平８−１２１５９７号公報、第４図
【０００７】
【発明が解決しようとする課題】
しかしながら、最初に記した従来の段差構造Ｓ１では、所定のガスケット形状とするためのシリンダー孔周辺部３ａと外方部３ｂとの位置合せが難しいため、ガスケット形状に求められている高い精度を満たすには専用の位置合せ治具と高精度のレーザー溶接装置が不可欠となり、ガスケットが高価なものになってしまうという問題があった。
【０００８】
また二番目に記した従来の段差構造Ｓ２では、シム板４の板厚が段差量となり、工業的に流通している薄鋼板の板厚が現状では５０μｍ（０．０５ｍｍ）区切りであるため、１０μｍ（０．０１ｍｍ）単位での高精度な段差量の設定ができず、また１００ μｍ以下の薄板ではレーザー溶接による歪みや変形や浮きの発生で段差機能の確保が困難となり、しかも最初の段差構造と同様、専用の位置合せ治具と高精度のレーザー溶接装置が不可欠となり、ガスケットが高価なものになってしまうという問題があった。
【０００９】
そして三番目に記した従来の段差構造Ｓ３では、単一板厚の薄鋼板を折り返し曲げ加工することから、その薄鋼板の板厚が段差量となるため、二番目の段差構造Ｓ２と同様、１０μｍ（０．０１ｍｍ）単位での高精度な段差量の設定ができず、しかも折り返し曲げ加工は絞り加工を用いて行うため、折り重ね部３ｃの形状の自由度が低く、割れの発生なしに充分広い半径方向幅の折り重ね部３ｃを形成するのは、特に薄鋼板では困難であるという問題があった。
【００１０】
【課題を解決するための手段およびその作用・効果】
この発明は上記課題を有利に解決して安価で段差量の制御の自由度の高い優れたメタルガスケットを提供することを目的とするものであり、請求項１記載のこの発明のシリンダーヘッド用メタルガスケットは、それぞれ金属板からなり、内燃機関のシリンダーブロックの各シリンダーボアに対応して形成されたシリンダー孔と、前記各シリンダー孔の周囲に形成された山形断面形状の環状ビードと、前記内燃機関のシリンダーブロックの冷却水ジャケットおよびシリンダーヘッドの冷却水孔に対応して前記各環状ビードの外側周辺部に形成された冷却水孔と、前記環状ビードおよび前記冷却水孔を全体的に囲繞する位置に形成された片斜面形断面形状の外周ビードとを有し、互いに重ね合わされる二枚の基板と、金属板からなり、前記二枚の基板間に介挿される副板と、前記副板の少なくとも片面上に接着されて、前記基板の前記各環状ビードと重なるとともにその環状ビードの頂部と対向するように前記環状ビードよりも半径方向内方の位置から半径方向外方の位置まで延在し、前記基板の前記各シリンダー孔を環状に囲む金属箔からなる金属箔層と、少なくとも加圧されつつ前記金属箔を前記副板に接着する接着剤からなる接着剤層と、を具えてなるものである。
【００１１】
かかるシリンダーヘッド用メタルガスケットによれば、二枚の基板間に介挿される副板の少なくとも片面に加圧接着された金属箔からなる金属箔層がそれを接着する接着剤からなる接着剤層と一緒に、基板の各環状ビードと重なるとともにその環状ビードの頂部と対向するようにその環状ビードよりも半径方向内方の位置から半径方向外方の位置まで延在し、基板の各シリンダー孔を環状に囲んで段差構造を構成するので、二枚の基板の環状ビードの頂部に加わる線圧が高くなって、シリンダーボア内の燃焼ガス圧に対し高いシール性能を発揮することができる。しかもこのメタルガスケットによれば、接着剤層をなす接着剤が、少なくとも加圧されつつ金属箔を副板に接着するので、接着剤を押して金属箔の下で流動させあるいは金属箔の下からその一部を押し出すことにより段差構造を容易に所望の厚さにし得て、環状ビードと外周ビードとの締付力のバランスを最適にする段差量を容易に得ることができる。
【００１２】
なお、この発明のメタルガスケットにおいては、請求項２に記載のように、前記副板に、前記基板の前記環状ビードと重なるとともに頂部同士が対向するように山形断面形状の環状ビードが形成されていてもよく、このようにすれば環状ビードが三段に重なるので、より高いシール性能を得ることができる。ちなみに、金属箔の接着は、環状ビードの成形前でも成形後でも良いが、成形前に行うと金属箔が環状ビードに正確に倣うので好ましい。
【００１３】
また、請求項３記載のこの発明のメタルガスケットは、それぞれ金属板からなり、内燃機関のシリンダーブロックの各シリンダーボアに対応して形成されたシリンダー孔と、前記各シリンダー孔の周囲に形成された山形断面形状の環状ビードと、前記内燃機関のシリンダーブロックの冷却水ジャケットおよびシリンダーヘッドの冷却水孔に対応して前記各環状ビードの外側周辺部に形成された冷却水孔と、前記環状ビードおよび前記冷却水孔を全体的に囲繞する位置に形成された片斜面形断面形状の外周ビードとを有し、互いに重ね合わされる二枚の基板と、前記二枚の基板の一方もしくは両方の、他方の基板に向く面上に接着されて、前記基板の前記各環状ビードと重なるとともにその環状ビードの頂部と対向するように前記環状ビードよりも半径方向内方の位置から半径方向外方の位置まで延在し、前記基板の前記各シリンダー孔を環状に囲む金属箔からなる金属箔層と、少なくとも加圧されつつ前記金属箔を前記副板に接着する接着剤からなる接着剤層と、を具えてなるものである。
【００１４】
このシリンダーヘッド用メタルガスケットによれば、二枚の基板の一方もしくは両方の、他方の基板に向く面に加圧接着された金属箔からなる金属箔層がそれを接着する接着剤からなる接着剤層と一緒に、基板の各環状ビードと重なるとともにその環状ビードの頂部と対向するようにその環状ビードよりも半径方向内方の位置から半径方向外方の位置まで延在し、基板の各シリンダー孔を環状に囲んで段差構造を構成するので、二枚構成のメタルガスケットでも、二枚の基板の環状ビードの頂部に加わる線圧が高くなって、シリンダーボア内の燃焼ガス圧に対し高いシール性能を発揮することができる。しかもこのメタルガスケットによれば、接着剤層をなす接着剤が、少なくとも加圧されつつ金属箔を副板に接着するので、接着剤を押して金属箔の下で流動させあるいは金属箔の下からその一部を押し出すことにより段差構造を容易に所望の厚さにし得て、環状ビードと外周ビードとの締付力のバランスを最適にする段差量を容易に得ることができる。
【００１５】
この発明における金属箔としては、アルミニウム、アルミニウム合金、鉄鋼、ステンレス鋼、青銅、チタン、またはニッケルからなり、硬度がＨｖ６０以上のものが好適である。かかる金属箔は耐熱性が高い上に、破損しにくく、形を保ち易いため、成形および接着時の取り扱いが容易だからである。
【００１６】
またこの発明における接着剤層の接着剤は、フェノール、エポキシ、ポリイミド、またはこれらのうち少なくとも二種の混合物からなるものが好適である。かかる接着剤は耐熱性が高いからである。
【００１７】
【発明の実施の形態】
以下に、この発明の実施の形態を実施例によって、図面に基づき詳細に説明する。ここに、図１は、この発明のシリンダーヘッド用メタルガスケットの第１実施例の全体を示す平面図、図２は、図１のＡ−Ａ線に沿う断面図、図３（ａ）〜（ｃ）は、上記第１実施例のメタルガスケットの副板に金属箔層を設ける方法を示す説明図であり、図中先の図１２〜図１４に示すと同様の部分はそれと同一の符号にて示す。すなわち、符号１はメタルガスケット、２は基板、３は副板をそれぞれ示す。
【００１８】
上記第１実施例のシリンダーヘッド用メタルガスケット１は、それぞれ外側面（シリンダーブロックおよびシリンダーヘッドに対向する面）のみ厚さ２５μｍのＮＢＲからなるラバー層のラバーコートを施された鋼板（ＳＵＳ３０１Ｈ０．２ｔ）からなり互いに重ね合わされる二枚の基板２と、それらの基板２間に介挿されるラバーコートなしの鋼板（ＳＵＳ３０１Ｈ０．２ｔ）からなる副板３とを具えている。
【００１９】
ここにおける二枚の基板２はそれぞれ、図１に示すように、内燃機関のシリンダーブロックの複数のシリンダーボアにそれぞれ対応して形成された複数のシリンダー孔２ａと、各シリンダー孔２ａの周囲に形成された山形断面形状（いわゆるフルビード形状）の環状ビード２ｂと、上記内燃機関のシリンダーブロックの冷却水ジャケットおよびシリンダーヘッドの冷却水孔に対応して各環状ビード２ｂの外側周辺部に形成された複数の冷却水孔２ｃと、複数の環状ビード２ｂおよびそれらの周囲に位置する複数の冷却水孔２ｃを全体的に囲繞する位置に形成された片斜面形断面形状（いわゆるハーフビード形状）の外周ビード２ｄとを有している。
【００２０】
またここにおける副板３は、図３（ａ）に示すように、上記基板２の各シリンダー孔２ａに対応するシリンダー孔３ｄと、上記基板２の冷却水孔２ｃのうちの幾つかに対応する冷却水孔３ｅとを有している。
【００２１】
この第１実施例のシリンダーヘッド用メタルガスケット１はさらに、図２に示すように、副板３の片面（図では上側の面）上に厚さ５０μｍの金属箔層５を、接着剤層７を介して具えており、この金属箔層５は、図３（ｂ）に示す如く副板のシリンダー孔３ｄの周辺部の平面形状に対応する平面形状に切り抜いた厚さ５０μｍで硬度Ｈｖ６０以上のアルミニウム箔６（日本軽金属株式会社製Ａ３００５（ＪＩＳＨ４０００））を、裏面にフェノール接着剤（株式会社東洋化学研究所製メタロックＮ２３）を塗布した状態で副板３の片面上に押しつけて、そのフェノール接着剤を挟んで熱板プレス等で加圧しつつ加熱して接着することで形成されたもので、副板３とともに二枚の基板２間に介挿されると、フェノール接着剤からなる接着剤層７と一緒に、基板２の各環状ビード２ｂと重なるとともにその環状ビード２ｂの頂部と対向するように環状ビード２ｂよりも半径方向内方の位置から半径方向外方の位置まで延在し、副板３の各シリンダー孔３ｄひいてはそれが対応する基板２の各シリンダー孔２ａを環状に囲むものである。
【００２２】
かかる第１実施例のメタルガスケット１によれば、二枚の基板２間に介挿される副板３の片面に加圧加熱接着されたアルミニウム箔６からなる金属箔層５がそれを接着するフェノール接着剤からなる接着剤層７と一緒に、基板２の各環状ビード２ｂと重なるとともにその環状ビード２ｂの頂部と対向するようにその環状ビード２ｂよりも半径方向内方の位置から半径方向外方の位置まで延在し、基板２の各シリンダー孔２ａを環状に囲んで段差量５０μｍ（接着剤層７は含まず）の段差構造Ｓ４を構成するので、二枚の基板２の環状ビード２ｂの頂部に加わる線圧が高くなって、後述の如く、シリンダーボア内のガス圧に対し高いシール性能を発揮することができる。
【００２３】
しかもこの第１実施例のメタルガスケット１によれば、接着剤層７をなすフェノール接着剤が、加熱および加圧されつつアルミニウム箔６を副板３に接着するので、硬化前のフェノール接着剤を押してアルミニウム箔６の下で流動させあるいはアルミニウム箔６の下からその一部を押し出すことにより段差構造を容易に所望の厚さにし得て、環状ビード２ｂと外周ビード２ｄとの締付力のバランスを最適にする段差量を容易に得ることができる。
【００２４】
さらにこの第１実施例のメタルガスケット１によれば、金属箔として、アルミニウムからなり、硬度がＨｖ６０以上のものを用いており、かかるアルミニウム箔６は耐熱性が高い上に、破損しにくく、形を保ち易いので、金属箔の成形および接着時の取り扱いを容易ならしめることができる。
【００２５】
またこの第１実施例のメタルガスケット１によれば、接着剤層７の接着剤として、フェノール接着剤を用いており、フェノール接着剤は耐熱性が高いので、ガスケットの耐熱性を高く維持することができる。
【００２６】
そしてこの第１実施例のメタルガスケット１によれば、二枚の基板２がそれぞれ鋼板の外側面をラバー層で被覆するラバーコートを施されているので、それらのラバー層がシリンダーブロックおよびシリンダーヘッドのデッキ面の微細な傷や加工痕を埋めてミクロシールの機能を果たすことで、シール性能を高めることができる。
【００２７】
図４は、この発明のシリンダーヘッド用メタルガスケットの第２実施例の、図１と同様の位置での断面図であり、この第２実施例のメタルガスケット１は、副板３の両面上に厚さ２５μｍのアルミニウム箔６（日本軽金属株式会社製Ａ３００５）をフェノール接着剤を挟んで加圧しつつ加熱接着することで副板３の両面上にそれぞれ厚さ２５μｍの金属箔層５を接着剤層７を介して具えて段差量５０μｍ（接着剤層７は含まず）の段差構造Ｓ５を構成している点のみが先の第１実施例と異なっており、それ以外は第１実施例と同一の構成とされている。この第２実施例によっても、先の第１実施例と同様の作用効果を得ることができる。
【００２８】
なお、平坦な副板３の片面上に接着剤層７および金属箔層５を具える第１実施例と同様の構成で、接着剤をフェノール接着剤とするとともに、厚さ５０μｍの金属箔層５の金属箔６をそれぞれ硬度がＨｖ６０以上の鉄鋼（ＳＰＣＣ）およびステンレス鋼（ＳＵＳ３０４）としたものをこの発明のシリンダーヘッド用メタルガスケットの第３実施例および第４実施例とする。これら第３および第４実施例によっても後述の如く、先の実施例と同様の高いシール性能を発揮することができる。
【００２９】
また、平坦な副板３の片面上に接着剤層７および金属箔層５を具える第１実施例と同様の構成で、接着剤をフェノール接着剤とするとともに厚さ５０μｍの金属箔層５の金属箔６をそれぞれ硬度がＨｖ６０以上の真鍮およびチタンとしたものをこの発明のシリンダーヘッド用メタルガスケットの第５実施例および第６実施例とする。これら第５および第６実施例によっても後述の如く、先の実施例と同様の高いシール性能を発揮することができる。
【００３０】
さらに、平坦な副板３の片面上に接着剤層７および金属箔層５を具える第１実施例と同様の構成で、厚さ５０μｍの金属箔層５の金属箔６を硬度がＨｖ６０以上のアルミニウムとするとともに、接着剤をそれぞれエポキシ接着剤およびポリイミド接着剤としたものをこの発明のシリンダーヘッド用メタルガスケットの第７実施例および第８実施例とする。これら第７および第８実施例によっても後述の如く、先の実施例と同様の高いシール性能を発揮することができる。
【００３１】
図５は、この発明のシリンダーヘッド用メタルガスケットの第９実施例の、図１と同様の位置での断面図であり、この第９実施例のメタルガスケット１は、副板３に、基板２の環状ビード２ｂと重なるとともに下側の基板２の環状ビード２ｂと頂部同士が対向するように山形断面形状の環状ビード３ｆが形成されていて、その副板３の片面（環状ビード３ｆの突出側の面）上に厚さ５０μｍのアルミニウム箔６をフェノール接着剤を挟んで加圧しつつ加熱接着することで副板３の片面上に厚さ５０μｍの金属箔層５を接着剤層７を介して具えて段差量５０μｍ（接着剤層７は含まず）の段差構造Ｓ６を構成する点のみが先の第１実施例と異なっており、それ以外は第１実施例と同一の構成とされている。この第９実施例によれば環状ビード２ｂ，３ｆが三段に重なるので、後述の如く、先の第１実施例よりも高いシール性能を得ることができる。
【００３２】
図６は、この発明のシリンダーヘッド用メタルガスケットの第１０実施例の、図１と同様の位置での断面図であり、この第１０実施例のメタルガスケット１は二枚の基板２の間に副板３を具えていないが、各基板２自体は先の実施例と同様のものである。そしてこの実施例では、片側（図では上側）の基板２の、他方の基板（図では下側の基板）２に向く面（内側面）上に厚さ５０μｍの金属箔層５を接着剤層７を介して具えており、この金属箔層５は、基板２のシリンダー孔２ａの周辺部の平面形状に対応する平面形状に切り抜いた厚さ５０μｍのアルミニウム箔６を、基板２の片面（環状ビード２ｂの突出側の面）上に接着剤としてのポリイミドフィルムを挟んで加圧しつつ加熱接着することで形成されたもので、二枚の基板２が重ね合わされると、ポリイミドフィルムからなる接着剤層７と一緒に、他方の基板２の各環状ビード２ｂと重なるとともにその環状ビード２ｂの頂部と対向するように環状ビード２ｂよりも半径方向内方の位置から半径方向外方の位置まで延在し、基板２の各シリンダー孔２ａを環状に囲んで段差量５０μｍの段差構造Ｓ７を構成するものである。
【００３３】
かかる第１０実施例のメタルガスケット１によれば、副板３がないのでガスケットを安価に製造でき、しかも後述の如く、先の第１実施例と概ね同等のシール性能を得ることができる。
【００３４】
以下の表１は、上記第１実施例〜第１０実施例のメタルガスケットおよび、第１実施例から金属箔層５と接着剤層７とを除いた比較例のメタルガスケットについて、構成およびシール性能を対比して示すものであり、ここにおけるシール性能は、図７に示すように上記各メタルガスケット１を自動車用エンジンのシリンダーブロックＳＢとシリンダーヘッドＳＨとの間に装着してヘッドボルトＨＢを規定軸力（３４．４ｋＮ／本）にて締付け、シリンダーボア内のピストンと燃焼室のバルブとを密閉処理した供試体につき、オーブン中で熱劣化温度２００ ℃、劣化時間４００時間の熱劣化試験を行い、その熱劣化試験の前の初期と熱劣化後とに室温雰囲気中で点火プラグ孔からシリンダーボア内にエアーを注入してシリンダーボア内を加圧して限界シール圧力を測定した結果を示すものである。
【００３５】
【表１】

この表１から、上記各実施例のメタルガスケットのシール性能および耐熱性能が比較例と比べて大幅に高いことが判る。
【００３６】
図８は、上記第１実施例と、上記比較例と同一の比較例１と、上記第１実施例と同一構造で金属箔層５の材質のみ異なる比較例２〜４とについての、熱劣化温度２００ ℃、劣化時間４００時間の熱劣化後のシール性能を対比して示す説明図である。この図８から、アルミニウム箔６を金属箔層５に用いた上記実施例のメタルガスケットは、銅箔を金属箔層５に用いた比較例２や、マグネシウム箔を金属箔層５に用いた比較例３や、銀箔を金属箔層５に用いた比較例４と比較して、耐熱性能が大幅に高いことが判る。
【００３７】
以上、図示例に基づき説明したが、この発明は上述の例に限定されるものでなく、例えば、基板２や副板３の、金属箔層５を設けられる面は、ラバーコートを施されていても良い。
【図面の簡単な説明】
【図１】この発明のシリンダーヘッド用メタルガスケットの第１実施例の全体を示す平面図である。
【図２】上記第１実施例のメタルガスケットの、図１のＡ−Ａ線に沿う断面図である。
【図３】（ａ）〜（ｃ）は、上記第１実施例のメタルガスケットの副板に樹脂層を設ける方法を示す説明図である。
【図４】この発明のシリンダーヘッド用メタルガスケットの第２実施例の、図１と同様の位置での断面図である。
【図５】この発明のシリンダーヘッド用メタルガスケットの第９実施例の、図１と同様の位置での断面図である。
【図６】この発明のシリンダーヘッド用メタルガスケットの第１０実施例の、図１と同様の位置での断面図である。
【図７】上記実施例および比較例のメタルガスケット１の限界シール圧力の測定方法を示す説明図である。
【図８】この発明の実施例および金属箔層の材質が異なる比較例についての熱劣化後シール性能を対比して示す説明図である。
【図９】従来のシリンダーヘッド用メタルガスケットの段差構造の一例を示す、図１と同様の位置での断面図である。
【図１０】従来のシリンダーヘッド用メタルガスケットの段差構造の他の一例を示す、図１と同様の位置での断面図である。
【図１１】従来のシリンダーヘッド用メタルガスケットの段差構造のさらに他の一例を示す、図１と同様の位置での断面図である。
【符号の説明】
１メタルガスケット
２基板
２ａ，３ｄシリンダー孔
２ｂ，３ｆ環状ビード
２ｃ，３ｅ冷却水孔
２ｄ外周ビード
３副板
３ａシリンダー孔周辺部
３ｂ外方部
３ｃ折り重ね部
４シム板
５金属箔層
６アルミニウム箔
７接着剤層
ＨＢヘッドボルト
ＬＷレーザー溶接部
Ｓ１〜Ｓ７段差構造
ＳＢシリンダーブロック
ＳＨシリンダーヘッド[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cylinder head metal gasket inserted between a cylinder block and a cylinder head of an internal combustion engine.
[0002]
[Prior art]
This type of metal gasket includes, for example, two substrates each made of a metal plate, and a sub-plate made of a metal plate having a thickness smaller than those substrates and interposed between the substrates. A substrate, a cylinder hole formed corresponding to each cylinder bore of the cylinder block of the internal combustion engine, an annular bead having a mountain-shaped cross section formed around each cylinder hole, and a cooling water jacket of the cylinder block of the internal combustion engine And a cooling water hole formed in the outer peripheral portion of each of the annular beads corresponding to the cooling water hole of the cylinder head, wherein the sub-plate has a cylinder hole and a cooling water hole similar to the substrate. A gasket is known. In such a metal gasket, a peripheral portion of a cylinder hole overlapping with an annular bead around each cylinder hole of a substrate is provided on a sub-plate. A step structure to be thicker than the outer portion of the outwardly disposed from Re, by raising the line pressure of the annular beads of the substrate, which may improve the sealing performance for the combustion gas in the cylinder.
[0003]
Conventionally, as the step structure, for example, as shown in FIG. 9, a sub plate 3 inserted between two substrates 2 made of steel plates (SUS301H 0.2t or the like) is inserted into each of the cylinder holes 2 a of the substrate 2. The peripheral portion 3a of the cylinder hole which overlaps the peripheral annular bead 2b and the outer portion 3b located outside thereof are made of thin steel plates (SUS 301H 0.2t, 0.3t, etc.) having different thicknesses. There is known a step structure S1 in which a stepped portion is formed and the peripheral portion 3a of the cylinder hole and the outer portion 3b are joined by laser welding (for example, see Patent Document 1). In addition, the code | symbol 1 in a figure shows a metal gasket, LW shows a laser welding part.
[0004]
For example, as shown in FIG. 10, each cylinder of the substrate 2 of the sub-plate 3 made of a thin steel plate having a single thickness (SUS 301H 0.1t or the like) interposed between two substrates 2 each made of a steel plate. A shim plate 4 also made of a thin steel plate (SUS 301H 0.1t or the like) is superimposed on a peripheral portion 3a of the cylinder hole overlapping with the annular bead 2b around the hole 2a so as to form a required step. There is also known a step structure S2 in which the plate 4 is joined by laser welding (for example, see Patent Document 2).
[0005]
Further, as shown in FIG. 11, for example, each of the sub-plates 3 made of a thin steel plate having a single thickness (SUS 301H 0.05t or the like) inserted between two substrates 2 made of steel plates, There is also known a stepped structure S3 in which a folded portion 3c is formed in the peripheral portion 3a of the cylinder hole overlapping with the annular bead 2b around the cylinder hole 2a by folding back to form a required step (for example, Patent Document 1). 3).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. Hei 7-243535, FIG. 3 [Patent Document 2]
JP-A-10-61772 [Patent Document 3]
JP-A-8-121597, FIG. 4
[Problems to be solved by the invention]
However, in the conventional step structure S1 described first, it is difficult to align the peripheral portion 3a and the outer portion 3b of the cylinder hole for forming a predetermined gasket shape, so that the high accuracy required for the gasket shape is satisfied. However, a dedicated positioning jig and a high-precision laser welding device are indispensable, and the gasket becomes expensive.
[0008]
Also, in the second conventional step structure S2, the thickness of the shim plate 4 is the step amount, and the thickness of the thin steel sheet distributed industrially is currently 50 μm (0.05 mm) break, It is not possible to set a highly accurate level difference in units of 10 μm (0.01 mm). In the case of a thin plate of 100 μm or less, it becomes difficult to secure the level difference function due to the occurrence of distortion, deformation or floating due to laser welding. As with the structure, a dedicated positioning jig and a high-precision laser welding device are indispensable, and there is a problem that the gasket becomes expensive.
[0009]
In the third conventional step structure S3, since a thin steel plate having a single thickness is folded back and processed, the thickness of the thin steel plate corresponds to the amount of the step, and thus, like the second step structure S2, It is not possible to set a highly accurate level difference in units of 10 μm (0.01 mm), and since the folding process is performed by drawing, the degree of freedom in the shape of the folded portion 3c is low, and no cracking occurs. There is a problem that it is difficult to form the folded portion 3c having a sufficiently wide radial width, particularly with a thin steel plate.
[0010]
[Means for Solving the Problems and Their Functions and Effects]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an excellent metal gasket which solves the above problems advantageously and is inexpensive and has a high degree of freedom in controlling the amount of step. The gasket is made of a metal plate, and has a cylinder hole formed corresponding to each cylinder bore of the cylinder block of the internal combustion engine, an angular bead having a chevron-shaped cross section formed around each cylinder hole, A cooling water hole formed in an outer peripheral portion of each annular bead corresponding to a cooling water jacket of the cylinder block and a cooling water hole of the cylinder head; and a position entirely surrounding the annular bead and the cooling water hole. An outer bead having a single-slope cross-sectional shape formed on the two substrates and a metal plate, which are superimposed on each other, A sub-plate interposed between the plates, and bonded to at least one surface of the sub-plate, radially inside the annular bead so as to overlap with each of the annular beads of the substrate and face the top of the annular bead. A metal foil layer extending from one position to a radially outward position and surrounding the cylinder holes of the substrate in a ring shape, and bonding the metal foil to the sub-plate while being pressed at least. An adhesive layer made of an adhesive.
[0011]
According to such a metal gasket for a cylinder head, a metal foil layer made of a metal foil pressure-bonded to at least one surface of a sub-plate inserted between two substrates has an adhesive layer made of an adhesive bonding the metal foil layer. Together, each of the cylinder holes of the substrate overlaps with each of the annular beads of the substrate and extends from a position radially inward of the annular bead to a position radially outward of the annular bead so as to face the top of the annular bead. Since the step structure is formed so as to surround the ring, the linear pressure applied to the top of the ring bead of the two substrates is increased, and high sealing performance against the combustion gas pressure in the cylinder bore can be exhibited. Moreover, according to this metal gasket, the adhesive forming the adhesive layer adheres the metal foil to the sub-plate while being pressed at least, so that the adhesive is pressed to flow under the metal foil or the metal foil is pressed from under the metal foil. By extruding a part, the step structure can be easily made to have a desired thickness, and a step amount that optimizes the balance of the tightening force between the annular bead and the outer bead can be easily obtained.
[0012]
In the metal gasket of the present invention, as described in claim 2, an annular bead having a chevron-shaped cross section is formed on the sub-plate so as to overlap with the annular bead of the substrate and to oppose the top. In this case, since the annular beads overlap in three stages, higher sealing performance can be obtained. Incidentally, the bonding of the metal foil may be performed before or after the formation of the annular bead, but it is preferable to perform the bonding before the formation, since the metal foil accurately follows the annular bead.
[0013]
The metal gasket according to the third aspect of the present invention is formed of a metal plate, and is formed around a cylinder hole formed corresponding to each cylinder bore of a cylinder block of an internal combustion engine, and around the cylinder hole. An annular bead having a chevron-shaped cross section, a cooling water hole formed in an outer peripheral portion of each annular bead corresponding to a cooling water jacket of a cylinder block and a cooling water hole of a cylinder head of the internal combustion engine, and the annular bead and An outer peripheral bead having a single-slope cross-sectional shape formed at a position surrounding the cooling water hole as a whole, two substrates overlapped with each other, and one or both of the two substrates, the other The annular bead is adhered on the surface facing the substrate and overlaps with each of the annular beads of the substrate and faces the top of the annular bead. A metal foil layer extending from a radially inner position to a radially outer position and surrounding the respective cylinder holes of the substrate in a ring shape, the metal foil layer being pressed at least while being pressed against the sub-foil. An adhesive layer made of an adhesive to be adhered to the plate.
[0014]
According to this cylinder head metal gasket, a metal foil layer made of a metal foil pressure-bonded to one or both of two substrates and a surface facing the other substrate is an adhesive made of an adhesive bonding the metal foil layer to the other substrate. Each cylinder of the substrate, together with the layer, extends from a position radially inward from the annular bead to a position radially outward from the annular bead so as to overlap each annular bead of the substrate and face the top of the annular bead. Since the hole is annularly surrounded to form a stepped structure, even with a two-piece metal gasket, the linear pressure applied to the top of the annular bead of the two boards increases, and a high seal against the combustion gas pressure in the cylinder bore Performance can be demonstrated. Moreover, according to this metal gasket, the adhesive forming the adhesive layer adheres the metal foil to the sub-plate while being pressed at least, so that the adhesive is pressed to flow under the metal foil or the metal foil is pressed from under the metal foil. By extruding a part, the step structure can be easily made to have a desired thickness, and a step amount that optimizes the balance of the tightening force between the annular bead and the outer bead can be easily obtained.
[0015]
The metal foil in the present invention is preferably made of aluminum, an aluminum alloy, steel, stainless steel, bronze, titanium, or nickel, and has a hardness of Hv 60 or more. This is because such a metal foil has high heat resistance, is hardly damaged, and is easy to maintain its shape, so that it is easy to handle during molding and bonding.
[0016]
The adhesive in the adhesive layer according to the present invention is preferably made of phenol, epoxy, polyimide, or a mixture of at least two of them. This is because such an adhesive has high heat resistance.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail by way of examples with reference to the drawings. Here, FIG. 1 is a plan view showing the entire first embodiment of the metal gasket for a cylinder head of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIGS. c) is an explanatory view showing a method of providing a metal foil layer on the sub-plate of the metal gasket of the first embodiment, in which parts similar to those shown in FIGS. 12 to 14 are denoted by the same reference numerals. Shown. That is, reference numeral 1 denotes a metal gasket, 2 denotes a substrate, and 3 denotes a subplate.
[0018]
The metal gasket 1 for a cylinder head of the first embodiment has a steel plate (SUS 301H 0) having a rubber layer of a rubber layer made of NBR having a thickness of 25 μm only on the outer surface (the surface facing the cylinder block and the cylinder head). . 2t) and a sub-plate 3 made of a steel plate without a rubber coat (SUS 301H 0.2t) interposed between the substrates 2.
[0019]
As shown in FIG. 1, each of the two substrates 2 has a plurality of cylinder holes 2a formed respectively corresponding to a plurality of cylinder bores of a cylinder block of an internal combustion engine and a plurality of cylinder holes 2a formed around each cylinder hole 2a. Annular beads 2b having a chevron cross-sectional shape (so-called full bead shape) and a plurality of annular beads 2b formed on the outer peripheral portion of each annular bead 2b corresponding to the cooling water jacket of the cylinder block and the cooling water hole of the cylinder head of the internal combustion engine. Cooling water hole 2c, a plurality of annular beads 2b and an outer peripheral bead 2d having a one-slope cross-sectional shape (a so-called half bead shape) formed at a position entirely surrounding the plurality of cooling water holes 2c located therearound. And
[0020]
As shown in FIG. 3A, the sub-plates 3 correspond to cylinder holes 3d corresponding to the respective cylinder holes 2a of the substrate 2 and some of the cooling water holes 2c of the substrate 2. And a cooling water hole 3e.
[0021]
As shown in FIG. 2, the metal gasket 1 for a cylinder head according to the first embodiment further includes a metal foil layer 5 having a thickness of 50 μm on one side (the upper side in the figure) of the sub-plate 3 and an adhesive layer 7. The metal foil layer 5 has a thickness of 50 μm and a hardness Hv of 60 or more cut out into a plane shape corresponding to the plane shape of the peripheral portion of the cylinder hole 3d of the sub-plate as shown in FIG. 3 (b). An aluminum foil 6 (A3005 (JIS H4000) manufactured by Nippon Light Metal Co., Ltd.) is pressed on one surface of the sub-plate 3 with a phenol adhesive (Metalock N23 manufactured by Toyo Chemical Laboratory Co., Ltd.) applied to the back surface, and the phenol is pressed. This is formed by heating and bonding while pressing the adhesive with a hot plate press or the like, and when inserted between the two substrates 2 together with the sub-plate 3, an adhesive layer made of a phenol adhesive 7 Together, each of the sub-plates 3 overlaps with each annular bead 2b of the substrate 2 and extends from a position radially inward of the annular bead 2b to a position radially outward of the annular bead 2 so as to face the top of the annular bead 2b. Each of the cylinder holes 3d and thus the corresponding cylinder hole 2a of the substrate 2 is annularly surrounded.
[0022]
According to the metal gasket 1 of the first embodiment, the metal foil layer 5 made of the aluminum foil 6 adhered to one side of the sub-plate 3 interposed between the two substrates 2 under pressure and heat is bonded to the phenol layer. Along with the adhesive layer 7 made of an adhesive, each annular bead 2b of the substrate 2 is overlapped with the annular bead 2b, and is opposed to the top of the annular bead 2b from a position radially inward of the annular bead 2b to a radially outward position. And a step structure S4 having a step amount of 50 μm (not including the adhesive layer 7) is formed by annularly surrounding each of the cylinder holes 2a of the substrate 2 so that the annular bead 2b of the two substrates 2 The linear pressure applied to the top increases, and as described later, high sealing performance can be exhibited with respect to the gas pressure in the cylinder bore.
[0023]
Moreover, according to the metal gasket 1 of the first embodiment, the phenol adhesive forming the adhesive layer 7 bonds the aluminum foil 6 to the sub-plate 3 while being heated and pressed. By pressing and flowing under the aluminum foil 6 or extruding a part thereof from under the aluminum foil 6, the step structure can be easily made to have a desired thickness, and the balance of the tightening force between the annular bead 2b and the outer bead 2d is achieved. Can be easily obtained.
[0024]
Further, according to the metal gasket 1 of the first embodiment, a metal foil made of aluminum and having a hardness of Hv 60 or more is used. Such an aluminum foil 6 has high heat resistance, is hardly damaged, and has a shape. Therefore, it is possible to easily handle the metal foil during molding and bonding.
[0025]
Further, according to the metal gasket 1 of the first embodiment, a phenol adhesive is used as the adhesive of the adhesive layer 7, and since the phenol adhesive has high heat resistance, the heat resistance of the gasket must be maintained high. Can be.
[0026]
According to the metal gasket 1 of the first embodiment, since the two substrates 2 are each provided with the rubber coat for covering the outer surface of the steel plate with the rubber layer, the rubber layers are formed by the cylinder block and the cylinder head. By filling the fine scratches and processing marks on the deck surface and performing the function of the micro seal, the sealing performance can be improved.
[0027]
FIG. 4 is a cross-sectional view of the second embodiment of the metal gasket for a cylinder head according to the present invention at the same position as that of FIG. 1. An aluminum foil 6 having a thickness of 25 μm (A3005 manufactured by Nippon Light Metal Co., Ltd.) is heated and bonded while pressing with a phenol adhesive in between to form a metal foil layer 5 having a thickness of 25 μm on both surfaces of the sub-plate 3. 7 is different from the first embodiment only in that a step structure S5 having a step amount of 50 μm (excluding the adhesive layer 7) is provided by way of the first embodiment. The configuration is as follows. According to the second embodiment, the same operation and effect as those of the first embodiment can be obtained.
[0028]
The same structure as in the first embodiment having the adhesive layer 7 and the metal foil layer 5 on one side of the flat sub-plate 3 is employed. The adhesive is a phenol adhesive, and the metal foil layer having a thickness of 50 μm is formed. The metal foil 6 of No. 5 is made of steel (SPCC) and stainless steel (SUS304) having a hardness of Hv 60 or more, respectively, as third and fourth embodiments of the metal gasket for a cylinder head according to the present invention. According to the third and fourth embodiments, as described later, the same high sealing performance as the previous embodiment can be exhibited.
[0029]
The same structure as in the first embodiment in which the adhesive layer 7 and the metal foil layer 5 are provided on one side of the flat sub-plate 3, and the adhesive is a phenol adhesive and the metal foil layer 5 having a thickness of 50 μm is used. The metal foils 6 made of brass and titanium each having a hardness of Hv 60 or more are referred to as fifth and sixth embodiments of the metal gasket for a cylinder head according to the present invention. According to the fifth and sixth embodiments, as described later, the same high sealing performance as in the previous embodiment can be exhibited.
[0030]
Further, the metal foil 6 of the metal foil layer 5 having a thickness of 50 μm has a hardness of Hv 60 or more in the same configuration as that of the first embodiment in which the adhesive layer 7 and the metal foil layer 5 are provided on one side of the flat sub-plate 3. The seventh embodiment and the eighth embodiment of the metal gasket for a cylinder head according to the present invention are made of aluminum as described above, and the adhesive is made of an epoxy adhesive and a polyimide adhesive, respectively. According to the seventh and eighth embodiments, as described later, the same high sealing performance as the previous embodiment can be exhibited.
[0031]
FIG. 5 is a sectional view of a ninth embodiment of a metal gasket for a cylinder head according to the present invention at the same position as that of FIG. 1. An annular bead 3f having an angled cross section is formed so as to overlap with the annular bead 2b of the lower substrate 2 and to face the annular bead 2b of the lower substrate 2 to each other, and one side of the sub-plate 3 (the projecting side of the annular bead 3f). The aluminum foil 6 having a thickness of 50 μm is heat-bonded while pressing with a phenol adhesive therebetween, so that the metal foil layer 5 having a thickness of 50 μm is formed on one side of the sub-plate 3 via the adhesive layer 7. It differs from the first embodiment only in that a step structure S6 having a step difference of 50 μm (excluding the adhesive layer 7) is provided, and the other structure is the same as that of the first embodiment. . According to the ninth embodiment, since the

annular beads

2b and 3f overlap in three stages, higher sealing performance can be obtained as compared with the first embodiment as described later.
[0032]
FIG. 6 is a cross-sectional view of a tenth embodiment of a metal gasket for a cylinder head according to the present invention at the same position as that of FIG. 1. A metal gasket 1 of the tenth embodiment is provided between two substrates 2. Although no sub-plate 3 is provided, each substrate 2 itself is the same as in the previous embodiment. In this embodiment, a metal foil layer 5 having a thickness of 50 μm is provided on one side (upper side in the figure) of the substrate 2 facing the other substrate (lower side in the figure) 2 (inner side) with an adhesive layer. 7, the metal foil layer 5 is formed by cutting an aluminum foil 6 having a thickness of 50 μm cut into a plane shape corresponding to the plane shape of the peripheral portion of the cylinder hole 2a of the substrate 2 on one side (annular shape) of the substrate 2. It is formed on the surface of the bead 2b on the protruding side) by heating and bonding while sandwiching a polyimide film as an adhesive. When the two substrates 2 are overlapped, an adhesive made of the polyimide film is formed. Together with the layer 7, it extends from the position radially inward of the annular bead 2b to the position radially outward of the annular bead 2b so as to overlap with each annular bead 2b of the other substrate 2 and face the top of the annular bead 2b. And each board of the substrate 2 The Nda hole 2a constitutes a step structure S7 in step amount 50μm surrounds annularly.
[0033]
According to the metal gasket 1 of the tenth embodiment, the gasket can be manufactured at a low cost because there is no sub-plate 3, and as described later, it is possible to obtain substantially the same sealing performance as that of the first embodiment.
[0034]
Table 1 below shows the configuration and sealing performance of the metal gaskets of the first to tenth embodiments and the metal gasket of the comparative example in which the metal foil layer 5 and the adhesive layer 7 were removed from the first embodiment. As shown in FIG. 7, the sealing performance is defined by mounting the metal gasket 1 between a cylinder block SB of an automobile engine and a cylinder head SH to define a head bolt HB. Tightening with an axial force (34.4 kN / piece) and performing a heat deterioration test of a heat deterioration temperature of 200 ° C. and a deterioration time of 400 hours in an oven on a specimen in which a piston in a cylinder bore and a valve in a combustion chamber are hermetically sealed. Air is injected into the cylinder bore from the spark plug hole at room temperature before and after the thermal degradation test, and the cylinder bore is pressurized. Te shows the result of measuring the critical sealing pressure.
[0035]
[Table 1]

From Table 1, it can be seen that the sealing performance and the heat resistance of the metal gasket of each of the above embodiments are significantly higher than those of the comparative example.
[0036]
FIG. 8 shows the thermal degradation of the first embodiment, the first comparative example that is the same as the first comparative example, and the second to fourth comparative examples that have the same structure as the first embodiment but differ only in the material of the metal foil layer 5. It is explanatory drawing which shows sealing performance after the temperature 200 degreeC and the heat degradation of 400 hours of degradation time in comparison. From FIG. 8, the metal gasket of the above embodiment using the aluminum foil 6 for the metal foil layer 5 shows the comparative example 2 using the copper foil for the metal foil layer 5 and the comparison using the magnesium foil for the metal foil layer 5. Compared with Example 3 and Comparative Example 4 using silver foil for the metal foil layer 5, it can be seen that the heat resistance is significantly higher.
[0037]
Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described examples. May be.
[Brief description of the drawings]
FIG. 1 is a plan view showing an entire first embodiment of a metal gasket for a cylinder head according to the present invention.
FIG. 2 is a cross-sectional view of the metal gasket according to the first embodiment, taken along line AA of FIG.
FIGS. 3A to 3C are explanatory views showing a method of providing a resin layer on a sub-plate of the metal gasket of the first embodiment.
FIG. 4 is a sectional view of a second embodiment of the metal gasket for a cylinder head according to the present invention at the same position as in FIG. 1;
FIG. 5 is a sectional view of a ninth embodiment of a metal gasket for a cylinder head according to the present invention at the same position as in FIG. 1;
FIG. 6 is a sectional view of a tenth embodiment of a metal gasket for a cylinder head according to the present invention at a position similar to that of FIG. 1;
FIG. 7 is an explanatory view showing a method of measuring a critical seal pressure of the metal gasket 1 of the above-described example and a comparative example.
FIG. 8 is an explanatory diagram for comparing the sealing performance after thermal deterioration of the embodiment of the present invention and a comparative example in which the material of the metal foil layer is different.
FIG. 9 is a cross-sectional view showing an example of a step structure of a conventional metal gasket for a cylinder head at a position similar to FIG.
FIG. 10 is a sectional view showing another example of the step structure of the conventional metal gasket for a cylinder head at a position similar to FIG.
FIG. 11 is a cross-sectional view showing still another example of the step structure of the conventional metal gasket for a cylinder head at a position similar to FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal gasket 2

Substrate

2a,

3d Cylinder hole

2b, 3f

Annular bead

2c, 3e Cooling water hole 2d Outer peripheral bead 3 Subplate 3a Cylinder hole peripheral part 3b Outer part 3c Folding part 4 Shim plate 5 Metal foil layer 6 Aluminum foil 7 Adhesive layer HB Head bolt LW Laser welds S1 to S7 Stepped structure SB Cylinder block SH Cylinder head

Claims

A cylinder hole (2a) formed of a metal plate and corresponding to each cylinder bore of the cylinder block of the internal combustion engine, and an annular bead (2b) having a chevron cross section formed around each cylinder hole; A cooling water hole (2c) formed in an outer peripheral portion of each annular bead corresponding to a cooling water jacket of a cylinder block and a cooling water hole of a cylinder head of the internal combustion engine; and the annular bead and the cooling water hole. Two substrates (2) having an outer peripheral bead (2d) having a single-slope cross-sectional shape formed at a position surrounding the whole, and superimposed on each other;
A sub-plate (3) made of a metal plate and inserted between the two substrates;
A position radially outward from a position radially inward of the annular bead from the position radially inward of the annular bead so as to be bonded to at least one surface of the sub-plate and overlap with each of the annular beads of the substrate and face the top of the annular bead. A metal foil layer (5) comprising a metal foil (6) extending in a circular manner and surrounding each of the cylinder holes of the substrate;
An adhesive layer (7) made of an adhesive for bonding the metal foil to the sub-plate at least while being pressed;
A metal gasket for cylinder heads.

2. The metal gasket for a cylinder head according to claim 1, wherein an annular bead having a chevron-shaped cross section is formed on the sub-plate so as to overlap the annular bead of the substrate and face a top portion of the annular bead. 3.

A cylinder hole (2a) formed of a metal plate and corresponding to each cylinder bore of the cylinder block of the internal combustion engine, and an annular bead (2b) having a chevron cross section formed around each cylinder hole; A cooling water hole (2c) formed in an outer peripheral portion of each annular bead corresponding to a cooling water jacket of a cylinder block and a cooling water hole of a cylinder head of the internal combustion engine; and the annular bead and the cooling water hole. Two substrates (2) having an outer peripheral bead (2d) having a single-slope cross-sectional shape formed at a position surrounding the whole, and superimposed on each other;
One or both of the two substrates are adhered on a surface facing the other substrate, and are more radially than the annular bead so as to overlap with the annular beads of the substrate and face the top of the annular bead. A metal foil layer (5) comprising a metal foil (6) extending from an inner position to a radially outer position and annularly surrounding each of the cylinder holes of the substrate;
An adhesive layer (7) made of an adhesive for bonding the metal foil to the sub-plate at least while being pressed;
A metal gasket for cylinder heads.

The metal foil (6) is made of aluminum, aluminum alloy, iron and steel, stainless steel, bronze, titanium, or nickel, and has a hardness of Hv 60 or more, and is characterized by the above-mentioned. Metal gasket for cylinder head as described.

The metal for a cylinder head according to any one of claims 1 to 4, wherein the adhesive of the adhesive layer (7) is made of phenol, epoxy, polyimide, or a mixture of at least two of them. gasket.