JP4631170B2

JP4631170B2 - Metal gasket

Info

Publication number: JP4631170B2
Application number: JP2001008139A
Authority: JP
Inventors: 志郎河合; 健二内田; 亮介藤木
Original assignee: Taiho Kogyo Co Ltd
Current assignee: Taiho Kogyo Co Ltd
Priority date: 2001-01-16
Filing date: 2001-01-16
Publication date: 2011-02-16
Anticipated expiration: 2021-01-16
Also published as: JP2002213615A

Description

【０００１】
【発明の属する技術分野】
本発明は金属ガスケットに関し、より詳しくは、燃焼室孔を囲繞する環状突起を有する金属ガスケットに関する。
【０００２】
【従来の技術】
従来、ガスケットとして、シリンダボアに合わせて金属製のガスケット基板に穿設した燃焼室孔と、上記ガスケット基板に燃焼室孔の円周方向に連続して形成され、かつ断面コ字形に突出する環状突起とを備えたものが知られている（特開平１０−１１０８２５号公報）。
そして上記環状突起は、燃焼室孔側となる内側壁面と、燃焼室孔側とは反対側の外側壁面と、両壁面を連結する天面とを備えており、上記環状突起における内側壁面と外側壁面との高さは同一となるように設定されている。
また、燃焼室孔を囲繞して環状ビードを設け、さらに燃焼室孔の周囲に穿設された流体孔にも該流体孔を囲繞して環状ビードを設け、さらに基板の外周縁部に外周ビードを設けたガスケットも知られている（特開平６−３３７０６８号公報）。
このガスケットにおいては、上記流体孔を囲繞する環状ビードの高さの設定を、燃焼室孔側の高さを上記外周ビード側の高さよりも高くし、さらに流体孔を囲繞する環状ビードと上記外周ビードとの連結部は外周ビードに向かってその高さが漸減するようにしている。
すなわち、エンジンの組み付け時に該ガスケットがシリンダヘッドとシリンダブロックによって挟持されると、燃焼室孔を囲繞した環状ビードと流体孔を囲繞した環状ビードおよび外周ビードが弾性変形によりシリンダヘッドもしくはシリンダブロックに密着するようにしたガスケットが知られている。
【０００３】
【発明が解決しようとする課題】
上記特開平１０−１１０８２５号公報の構成を有する金属ガスケットをエンジンに組み付けた状態では、シリンダブロックとシリンダヘッドに上記環状突起が挟まれるため、シリンダブロックとシリンダヘッドとの間に微少な間隙が生じるようになり、この間隙は締結ボルト部を基点として燃焼室に向かって次第に大きくなる。
その結果、上記間隙が燃焼室に向かって次第に大きくなっていく一方、上記環状突起の内側壁面の高さと外側壁面との高さは同一であるため、環状突起における天面の内側部分とシリンダヘッドとの間に間隙が生じ易くなり、シリンダヘッドと環状突起の天面との接触範囲が狭くなってシール性を悪化させていた。また、これと同時に、環状突起における天面の外側部分により多くの荷重がかかるようになるので、天面の外側部分で亀裂が生じやすくなり、ひいては金属ガスケットのシール性が低下するという恐れがあった。
また上記特開平６−３３７０６８号公報の構成を有するガスケットでは、流体孔を囲繞する環状ビードの形状については考慮されているが、シリンダブロックとシリンダヘッドとの間の微少な間隙については特に考慮されておらず、しかも燃焼室孔周辺には従来の断面半円形のビードしか設けられていないため、上記環状突起のように面接触でシールを行うのではなく、線接触でシールを行うためにビードとシリンダブロックもしくはシリンダヘッドとの接触面積が少なく、シール性がよくなかった。
本発明は以上のような事情に鑑み、環状突起の天面全体に可及的に均等に荷重をかけることができるようにして、シール性の向上を図った金属ガスケットを提供するものである。
【０００４】
【課題を解決するための手段】
すなわち請求項１の発明は、シリンダボアに合わせて金属製のガスケット基板に穿設した燃焼室孔と、上記ガスケット基板に燃焼室孔の円周方向に連続して形成され、かつ断面コ字形に突出する環状突起とを有し、上記環状突起は、燃焼室孔側となる内側壁面と、燃焼室孔側とは反対側の外側壁面と、両壁面を連結する天面とを備える金属ガスケットにおいて、
上記外側壁面の高さを内側壁面の高さよりも小さく設定し、
また上記ガスケット基板と内側壁面の間、およびガスケット基板と外側壁面との間をそれぞれ内側基板円弧部と外側基板円弧部とを介して連結するとともに、外側基板円弧部の曲率半径を内側基板円弧部の曲率半径よりも大きく設定し、
さらに上記内側壁面と天面との間、および外側壁面と天面の間をそれぞれ内側天面円弧部と外側天面円弧部とを介して連結するとともに、外側天面円弧部の曲率半径を内側天面円弧部の曲率半径よりも大きく設定したことを特徴としている。
【０００５】
また請求項４の発明は、シリンダボアに合わせて金属製のガスケット基板に穿設した燃焼室孔と、上記ガスケット基板に燃焼室孔の円周方向に連続して形成され、かつ断面コ字形に突出する環状突起とを有し、上記環状突起は、燃焼室孔側となる内側壁面と、燃焼室孔側とは反対側の外側壁面と、両壁面を連結する天面とを備える金属ガスケットにおいて、
上記外側壁面の高さを内側壁面の高さよりも小さく設定し、
また上記ガスケット基板と外側壁面との間の外側角度を、ガスケット基板と内側壁面との間の内側角度よりも大きく設定したことを特徴としている。
【０００６】
さらに請求項７の発明は、シリンダボアに合わせて金属製のガスケット基板に穿設した燃焼室孔と、上記ガスケット基板に燃焼室孔の円周方向に連続して形成され、かつ断面コ字形に突出する環状突起とを有し、上記環状突起は、燃焼室孔側となる内側壁面と、燃焼室孔側とは反対側の外側壁面と、両壁面を連結する天面とを備える金属ガスケットにおいて、
上記外側壁面の高さを内側壁面の高さよりも小さく設定し、
また上記ガスケット基板と内側壁面の間、およびガスケット基板と外側壁面との間をそれぞれ内側基板円弧部と外側基板円弧部とを介して連結するとともに、外側基板円弧部の曲率半径を内側基板円弧部の曲率半径よりも大きく設定し、
さらに上記内側壁面と天面との間、および外側壁面と天面の間をそれぞれ内側天面円弧部と外側天面円弧部とを介して連結するとともに、外側天面円弧部の曲率半径を内側天面円弧部の曲率半径よりも大きく設定し，
また上記ガスケット基板と外側壁面との間の外側角度を、ガスケット基板と内側壁面との間の内側角度よりも大きく設定したことを特徴としている。
【００１１】
上記各請求項の発明によれば、いずれの構成においても環状突起の天面にかかる荷重を均一なものにすることができるため、従来に比較して金属ガスケットのシール性を向上させることができ、また環状突起における天面の外側部分に発生していた亀裂を防止することができる。
【００１２】
【発明の実施の形態】
以下図示実施例について本発明を説明すると、図１ないし図２において、金属ガスケット１は、図示しないシリンダヘッドとシリンダブロックとの間に挟持されてそれらの間をシールするようになっている。
本実施例の金属ガスケット１は、一枚の金属製のガスケット基板２から構成してあり、このガスケット基板２には、図示しないシリンダブロックのシリンダボアに合わせて穿設した複数の燃焼室孔３と、図示しない締結ボルトを挿通するための複数のボルト孔４と、潤滑油を流通させる油孔５および冷却水を流通させるための水孔６をそれぞれ穿設している。
また、図２に示すように、ガスケット基板２には、燃焼室孔３を囲繞してその上方側に向けて膨出する無端状のビード部７と、ビード部７よりも内方側の位置で燃焼室孔３を囲繞する無端状の環状突起１１を形成している。このビード部７と環状突起１１は、それぞれガスケット基板２を下面側から上面側に向けてプレス加工することによって形成されている。
上記環状突起１１は断面コ字形に形成され、燃焼室孔３側となる内側壁面１１Ａと、燃焼室孔３とは反対側に形成された外側壁面１１Ｂと、さらに内側壁面１１Ａと外側壁面１１Ｂとを連結する天面１１Ｃとを備えている。
【００１３】
ここで、上述したように従来の内側壁面１１Ａと外側壁面１１Ｂとの高さが同一である環状突起１１を備えた金属ガスケット１をエンジンに組み付けると、環状突起によってシリンダブロックとシリンダヘッドの間隙が燃焼室に向かって次第に大きくなっていくために、環状突起における天面の内側部分とシリンダヘッドとの間に間隙が生じ、シリンダヘッドと環状突起の天面との接触範囲が狭くなる。また、天面１１Ｃの外側部分にその内側部分より多くの荷重がかかるので、シール性の悪化や金属ガスケットの破損につながっていた。
そこで本実施例では、天面１１Ｃの全体でエンジン組み付け時の荷重を受けることができるようにするため、以下の３種の構成を組み合わせて環状突起１１を形成している。
【００１４】
すなわち第１の構成は、ガスケット基板２を基準にした内側壁面１１Ａの高さをｔ１とし、ガスケット基板２を基準にした外側壁面１１Ｂの高さをｔ２としたときに、外側壁面の高さｔ２を内側壁面の高さｔ１よりも小さくしている。これにより環状突起１１の断面形状をシリンダブロックとシリンダヘッドの間隙の形状に合わせることができ、したがってシリンダヘッドと天面１１Ｃの接触範囲を天面１１Ｃ全体とすることができるとともに、天面１１Ｃの外側部分に加えられる荷重を緩和することが可能となる。
【００１５】
次に、第２の構成としては、環状突起１１を形成する際に環状突起１１に形成されるコーナー部に円弧部を持たせている。すなわち、ガスケット基板２と内側壁面１１Ａとの間の円弧部を内側基板円弧部Ｒ１ａ、ガスケット基板２と外側壁面１１Ｂとの間の円弧部を外側基板円弧部Ｒ１ｂとし、かつ、内側基板円弧部Ｒ１ａの曲率半径を内側基板曲率半径ｒ１ａ、外側基板円弧部Ｒ１ｂの曲率半径を外側基板曲率半径ｒ１ｂとしている。
また、天面１１Ｃと内側壁面１１Ａとの間の円弧部を内側天面円弧部Ｒ２ａ、天面１１Ｃと外側壁面１１Ｂとの間の円弧部を外側天面円弧部Ｒ２ｂとし、かつ、内側天面円弧部Ｒ２ａの半径を内側天面曲率半径ｒ２ａ、外側天面円弧部Ｒ２ｂの半径を外側天面曲率半径ｒ２ｂとしている。
そして、外側基板曲率半径ｒ１ｂを内側基板曲率半径ｒ１ａよりも大きくし、また外側天面曲率半径ｒ２ｂを内側天面曲率半径ｒ２ａよりも大きく設定することで、環状突起１１の外側の円弧部Ｒ１ｂ，Ｒ２ｂの剛性を内側の円弧部Ｒ１ａ，Ｒ２ａの剛性よりも低くすることができる。
これにより、環状突起１１の外側部分が内側部分よりも変形し易くなるため、シリンダヘッドと天面１１Ｃの接触範囲を天面１１Ｃの全体とすることができるとともに、天面１１Ｃの外側部分に加えられる荷重を緩和することが可能となる。
【００１６】
さらに第３の構成においては、ガスケット基板２と内側壁面１１Ａとの間の角度を内側角度θ１とし、ガスケット基板２と外側壁面１１Ｂの間の角度を外側角度θ２としている。そして、外側角度θ２を内側角度θ１よりも大きく設定することにより、環状突起１１の外側部分の剛性を内側部分の剛性よりも低くすることができる。
これにより、環状突起１１の外側部分が内側部分よりも変形し易くなるため、シリンダヘッドと天面１１Ｃの接触範囲を天面１１Ｃの全体とすることができるとともに、天面１１Ｃの外側部分に加えられる荷重を緩和することが可能となる。
【００１７】
次に、エンジンの組み付け時、すなわちシリンダブロックとシリンダヘッドが金属ガスケット１を介して締結ボルトによって締結された際には、ガスケット基板２における燃焼室孔３の周囲では締結ボルトの位置によって荷重の強弱が発生する。この荷重の強弱は、図１における締結ボルトの近傍部１２で大きくなり、締結ボルトの中間部１３で小さくなる。
そこで本実施例では、締結ボルトの近傍部１２と中間部１３とのそれぞれの領域で上記第１から第３の構成について、それぞれの寸法を変化させることで天面１１Ｃにかかる面圧分布を均一なものとしている。
【００１８】
すなわち第１の構成に対しては、締結ボルトの近傍部１２と締結ボルトの中間部１３とで内側壁面高さｔ１と外側壁面高さｔ２の値を変化させている。
より具体的には、締結ボルトの近傍部１２における壁面高さｔ１、ｔ２を締結ボルトの中間部１３での壁面高さｔ１、ｔ２よりもそれぞれ低くすることで、締結ボルトの近傍部１２での天面１１Ｃにかかる面圧を締結ボルトの中間部１３にかかる面圧と略等しくすることが可能となり、これにより天面１１Ｃにかかる面圧分布を均一なものとすることができる。この場合、内側壁面高さｔ１と外側壁面高さｔ２とのいずれか一方のみの高さを異ならせるようにしてもよい。
【００１９】
また、第２の構成に対しては、締結ボルトの近傍部１２と中間部１３とで内側基板曲率半径ｒ２ａ、外側基板曲率半径ｒ２ｂ、内側天面曲率半径ｒ２ａおよび外側天面曲率半径ｒ２ｂの値を変化させている。
すなわち、締結ボルトの近傍部１２での環状突起１１の内側基板曲率半径ｒ２ａ、外側基板曲率半径ｒ２ｂ、内側天面曲率半径ｒ２ａおよび外側天面曲率半径ｒ２ｂの大きさを締結ボルトの中間部１３でのそれぞれの値よりそれぞれ大きくすることで、締結ボルトの近傍部１２での環状突起１１の剛性を締結ボルトの中間部１３での剛性よりも低くしている。したがって、締結ボルトの近傍部１２での天面１１Ｃにかかる面圧を締結ボルトの中間部１３にかかる面圧と等しくすることが可能となるので、天面１１Ｃにかかる面圧分布を均一なものとすることができる。
この場合においても、上記内側基板円弧部、外側基板円弧部、内側天面円弧部および外側天面円弧部のうち少なくとも１つの曲率半径を締結ボルトの近傍で大きく、締結ボルトから離れた位置で小さく設定してもよい。
【００２０】
さらに第３の構成に対しては、締結ボルトの近傍部１２と中間部１３とで内側角度θ１と外側角度θ２の値を変化させるものである。
すなわち、締結ボルトの近傍部１２での内側角度θ１と外側角度θ２の大きさを締結ボルトの中間部１３での内側角度θ１と外側角度θ２の値よりもそれぞれ大きくすることで、締結ボルトの近傍部１２での環状突起１１の剛性を締結ボルトの中間部１３での剛性よりも低くすることができる。
これにより、締結ボルトの近傍部１２での天面１１Ｃにかかる面圧を締結ボルトの中間部１３にかかる面圧と等しくすることが可能となるので、天面１１Ｃにかかる面圧分布を均一なものとすることができる。
そしてこの場合においても、上記外側角度および内側角度のうち少なくともいずれか一方を締結ボルトの近傍で大きく、締結ボルトから離れた位置で小さく設定してもよい。
【００２１】
なお、上記実施例では上記第１から第３の構成を複合的に用い、しかもその形状を締結ボルトの近傍部１２と締結ボルトの中間部１３との間で変化させているが、第１ないし第３の構成を単独で用いてもよく、或いは２種の構成を組み合わせてもよい。
【００２２】
【発明の効果】
以上のように、本発明によれば、環状突起の天面にかかる荷重を均一なものにすることができるため、従来に比較して金属ガスケットのシール性を向上させることができ、また環状突起における天面の外側部分に発生していた亀裂を防止することができるという効果が得られる。
【図面の簡単な説明】
【図１】本発明の金属ガスケットを示す平面図。
【図２】図１のＩＩ−ＩＩ線に沿う拡大断面図。
【符号の説明】
１金属ガスケット２ガスケット基板
３燃焼室孔１１環状突起
１１Ａ内側壁面１１Ｂ外側壁面
１１Ｃ天面ｔ１、ｔ２壁面高さ
Ｒ１ａ内側基板円弧部Ｒ１ｂ外側基板円弧部
Ｒ２ａ内側天面円弧部Ｒ２ｂ外側天面円弧部
ｒ１ａ内側基板曲率半径ｒ１ｂ外側基板曲率半径
ｒ２ａ内側天面曲率半径ｒ２ｂ外側天面曲率半径
θ１内側角度 θ２外側角度[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal gasket, and more particularly to a metal gasket having an annular protrusion surrounding a combustion chamber hole.
[0002]
[Prior art]
Conventionally, as a gasket, a combustion chamber hole formed in a metal gasket substrate in accordance with a cylinder bore, and an annular protrusion formed continuously in the circumferential direction of the combustion chamber hole in the gasket substrate and projecting in a U-shaped cross section Are known (Japanese Patent Laid-Open No. 10-110825).
The annular projection includes an inner wall surface on the combustion chamber hole side, an outer wall surface on the opposite side to the combustion chamber hole side, and a top surface that connects both wall surfaces. The height with the wall surface is set to be the same.
Further, an annular bead is provided to surround the combustion chamber hole, and an annular bead is also provided around the fluid hole formed around the combustion chamber hole, and an outer peripheral bead is provided on the outer peripheral edge of the substrate. There is also known a gasket provided with (Japanese Patent Laid-Open No. 6-337068).
In this gasket, the height of the annular bead surrounding the fluid hole is set such that the height on the combustion chamber hole side is higher than the height on the outer peripheral bead side, and the annular bead surrounding the fluid hole and the outer periphery The connecting portion with the bead gradually decreases in height toward the outer peripheral bead.
That is, when the gasket is sandwiched between the cylinder head and the cylinder block when the engine is assembled, the annular bead surrounding the combustion chamber hole, the annular bead surrounding the fluid hole, and the outer peripheral bead are brought into close contact with the cylinder head or the cylinder block due to elastic deformation. Gaskets designed to do this are known.
[0003]
[Problems to be solved by the invention]
In the state in which the metal gasket having the configuration described in Japanese Patent Laid-Open No. 10-110825 is assembled to the engine, the annular projection is sandwiched between the cylinder block and the cylinder head, so that a minute gap is generated between the cylinder block and the cylinder head. Thus, this gap gradually increases from the fastening bolt portion toward the combustion chamber.
As a result, while the gap gradually increases toward the combustion chamber, the height of the inner wall surface of the annular protrusion and the height of the outer wall surface are the same. Between the cylinder head and the top surface of the annular projection becomes narrow, and the sealing performance is deteriorated. At the same time, since a larger load is applied to the outer portion of the top surface of the annular projection, cracks are likely to occur in the outer portion of the top surface, and there is a risk that the sealing performance of the metal gasket will be lowered. It was.
In addition, in the gasket having the configuration disclosed in Japanese Patent Laid-Open No. 6-337068, the shape of the annular bead surrounding the fluid hole is taken into consideration, but the minute gap between the cylinder block and the cylinder head is particularly taken into consideration. In addition, since only the conventional semicircular bead is provided around the combustion chamber hole, the bead is used for sealing by line contact instead of sealing by surface contact as in the case of the annular protrusion. The contact area between the cylinder block and the cylinder head is small, and the sealing performance is not good.
In view of the circumstances as described above, the present invention provides a metal gasket in which a load can be applied as evenly as possible to the entire top surface of an annular protrusion so as to improve sealing performance.
[0004]
[Means for Solving the Problems]
That is, the invention according to claim 1 is a combustion chamber hole formed in a metal gasket substrate in accordance with the cylinder bore, and is formed continuously in the circumferential direction of the combustion chamber hole in the gasket substrate and protrudes in a U-shaped cross section. In the metal gasket provided with an inner wall surface on the combustion chamber hole side, an outer wall surface on the opposite side to the combustion chamber hole side, and a top surface that connects both wall surfaces,
Set the height of the outer wall surface smaller than the height of the inner wall surface,
Further, the gasket substrate and the inner wall surface, and the gasket substrate and the outer wall surface are connected via an inner substrate arc portion and an outer substrate arc portion, respectively, and the curvature radius of the outer substrate arc portion is set to the inner substrate arc portion. Set larger than the radius of curvature of
Further, the inner wall surface and the top surface, and the outer wall surface and the top surface are connected via the inner top surface arc portion and the outer top surface arc portion, respectively, and the curvature radius of the outer top surface arc portion is set to the inside. It is characterized in that it is set larger than the radius of curvature of the top arc portion.
[0005]
According to a fourth aspect of the present invention, there is provided a combustion chamber hole formed in a metal gasket substrate in accordance with a cylinder bore, and the gasket substrate is formed continuously in the circumferential direction of the combustion chamber hole and protrudes in a U-shaped cross section. In the metal gasket provided with an inner wall surface on the combustion chamber hole side, an outer wall surface on the opposite side to the combustion chamber hole side, and a top surface that connects both wall surfaces,
Set the height of the outer wall surface smaller than the height of the inner wall surface,
The outer angle between the gasket substrate and the outer wall surface is set larger than the inner angle between the gasket substrate and the inner wall surface.
[0006]
Furthermore, the invention of claim 7 is a combustion chamber hole formed in a metal gasket substrate in alignment with the cylinder bore, and is formed continuously in the circumferential direction of the combustion chamber hole in the gasket substrate and protrudes in a U-shaped cross section. In the metal gasket provided with an inner wall surface on the combustion chamber hole side, an outer wall surface on the opposite side to the combustion chamber hole side, and a top surface that connects both wall surfaces,
Set the height of the outer wall surface smaller than the height of the inner wall surface,
Further, the gasket substrate and the inner wall surface, and the gasket substrate and the outer wall surface are connected via an inner substrate arc portion and an outer substrate arc portion, respectively, and the curvature radius of the outer substrate arc portion is set to the inner substrate arc portion. Set larger than the radius of curvature of
Further, the inner wall surface and the top surface, and the outer wall surface and the top surface are connected via the inner top surface arc portion and the outer top surface arc portion, respectively, and the curvature radius of the outer top surface arc portion is set to the inside. Set larger than the radius of curvature of the top arc,
The outer angle between the gasket substrate and the outer wall surface is set larger than the inner angle between the gasket substrate and the inner wall surface.
[0011]
According to the inventions of the above claims , since the load applied to the top surface of the annular protrusion can be made uniform in any configuration, the sealing performance of the metal gasket can be improved as compared with the conventional case. Moreover, the crack which has generate | occur | produced in the outer part of the top | upper surface in a cyclic | annular protrusion can be prevented.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the illustrated embodiments. In FIGS. 1 and 2, a metal gasket 1 is sandwiched between a cylinder head and a cylinder block (not shown) so as to seal between them.
The metal gasket 1 of this embodiment is composed of a single metal gasket substrate 2, and the gasket substrate 2 includes a plurality of combustion chamber holes 3 drilled in accordance with cylinder bores of a cylinder block (not shown). A plurality of bolt holes 4 for inserting fastening bolts (not shown), an oil hole 5 for circulating lubricating oil, and a water hole 6 for circulating cooling water are formed.
As shown in FIG. 2, the gasket substrate 2 includes an endless bead portion 7 that surrounds the combustion chamber hole 3 and bulges upward, and a position on the inner side of the bead portion 7. Thus, an endless annular projection 11 surrounding the combustion chamber hole 3 is formed. The bead portion 7 and the annular protrusion 11 are each formed by pressing the gasket substrate 2 from the lower surface side toward the upper surface side.
The annular protrusion 11 is formed in a U-shaped cross section, and has an inner wall surface 11A on the combustion chamber hole 3 side, an outer wall surface 11B formed on the opposite side to the combustion chamber hole 3, and an inner wall surface 11A and an outer wall surface 11B. And a top surface 11C for connecting the two.
[0013]
Here, as described above, when the metal gasket 1 provided with the annular protrusion 11 having the same height of the inner wall surface 11A and the outer wall surface 11B is assembled to the engine, the gap between the cylinder block and the cylinder head is caused by the annular protrusion. Since it gradually increases toward the combustion chamber, a gap is formed between the inner portion of the top surface of the annular protrusion and the cylinder head, and the contact range between the cylinder head and the top surface of the annular protrusion is narrowed. In addition, since more load is applied to the outer portion of the top surface 11C than to the inner portion thereof, the sealing performance is deteriorated and the metal gasket is damaged.
Therefore, in the present embodiment, the annular projection 11 is formed by combining the following three types of structures so that the entire top surface 11C can receive a load during assembly of the engine.
[0014]
That is, in the first configuration, when the height of the inner wall surface 11A with reference to the gasket substrate 2 is t1, and the height of the outer wall surface 11B with reference to the gasket substrate 2 is t2, the height t2 of the outer wall surface is set. Is smaller than the height t1 of the inner wall surface. As a result, the cross-sectional shape of the annular protrusion 11 can be matched with the shape of the gap between the cylinder block and the cylinder head, so that the contact range between the cylinder head and the top surface 11C can be the entire top surface 11C, and the top surface 11C It becomes possible to relieve the load applied to the outer portion.
[0015]
Next, as a second configuration, when the annular protrusion 11 is formed, the corner portion formed on the annular protrusion 11 has an arc portion. That is, the arc portion between the gasket substrate 2 and the inner wall surface 11A is the inner substrate arc portion R1a, the arc portion between the gasket substrate 2 and the outer wall surface 11B is the outer substrate arc portion R1b, and the inner substrate arc portion R1a. Is the inner substrate curvature radius r1a, and the outer substrate arcuate portion R1b is the outer substrate curvature radius r1b.
An arc portion between the top surface 11C and the inner wall surface 11A is an inner top surface arc portion R2a, and an arc portion between the top surface 11C and the outer wall surface 11B is an outer top surface arc portion R2b. The radius of the arc portion R2a is the inner top surface radius of curvature r2a, and the radius of the outer top surface arc portion R2b is the outer top surface radius of curvature r2b.
Then, by setting the outer substrate curvature radius r1b to be larger than the inner substrate curvature radius r1a and setting the outer top surface curvature radius r2b to be larger than the inner top surface curvature radius r2a, the outer arc portion R1b, The rigidity of R2b can be made lower than the rigidity of the inner arc portions R1a and R2a.
As a result, the outer portion of the annular protrusion 11 is more easily deformed than the inner portion, so that the contact range between the cylinder head and the top surface 11C can be the entire top surface 11C, and in addition to the outer portion of the top surface 11C. It is possible to reduce the load applied.
[0016]
Furthermore, in the third configuration, the angle between the gasket substrate 2 and the inner wall surface 11A is the inner angle θ1, and the angle between the gasket substrate 2 and the outer wall surface 11B is the outer angle θ2. And the rigidity of the outer part of the annular protrusion 11 can be made lower than the rigidity of the inner part by setting the outer angle θ2 to be larger than the inner angle θ1.
As a result, the outer portion of the annular protrusion 11 is more easily deformed than the inner portion, so that the contact range between the cylinder head and the top surface 11C can be the entire top surface 11C, and in addition to the outer portion of the top surface 11C. It is possible to reduce the load applied.
[0017]
Next, when the engine is assembled, that is, when the cylinder block and the cylinder head are fastened by the fastening bolt via the metal gasket 1, the load intensity is increased or decreased depending on the position of the fastening bolt around the combustion chamber hole 3 in the gasket substrate 2. Will occur. The strength of the load increases at the vicinity 12 of the fastening bolt in FIG. 1 and decreases at the intermediate portion 13 of the fastening bolt.
Therefore, in this embodiment, the surface pressure distribution applied to the top surface 11C is made uniform by changing the respective dimensions of the first to third configurations in the vicinity of the fastening bolt 12 and the intermediate portion 13. It is supposed to be.
[0018]
That is, for the first configuration, the values of the inner wall surface height t1 and the outer wall surface height t2 are changed in the vicinity portion 12 of the fastening bolt and the intermediate portion 13 of the fastening bolt.
More specifically, wall surface heights t1 and t2 in the vicinity 12 of the fastening bolt are set lower than wall surface heights t1 and t2 in the intermediate part 13 of the fastening bolt, respectively. The surface pressure applied to the top surface 11C can be made substantially equal to the surface pressure applied to the intermediate portion 13 of the fastening bolt, whereby the surface pressure distribution applied to the top surface 11C can be made uniform. In this case, only one of the inner wall surface height t1 and the outer wall surface height t2 may be made different.
[0019]
Further, for the second configuration, the values of the inner substrate curvature radius r2a, the outer substrate curvature radius r2b, the inner top surface curvature radius r2a, and the outer top surface curvature radius r2b at the vicinity 12 and the intermediate portion 13 of the fastening bolt. Is changing.
That is, the inner board curvature radius r2a, the outer board curvature radius r2b, the inner top surface curvature radius r2a, and the outer top curvature radius r2b of the annular protrusion 11 in the vicinity 12 of the fastening bolt are set at the intermediate portion 13 of the fastening bolt. The rigidity of the annular projection 11 at the vicinity 12 of the fastening bolt is made lower than the rigidity at the intermediate portion 13 of the fastening bolt. Accordingly, the surface pressure applied to the top surface 11C in the vicinity 12 of the fastening bolt can be made equal to the surface pressure applied to the intermediate portion 13 of the fastening bolt, so that the surface pressure distribution applied to the top surface 11C is uniform. It can be.
Even in this case, at least one of the inner substrate arc portion, the outer substrate arc portion, the inner top surface arc portion, and the outer top surface arc portion has a radius of curvature that is large in the vicinity of the fastening bolt and small in a position away from the fastening bolt. It may be set.
[0020]
Further, for the third configuration, the values of the inner angle θ1 and the outer angle θ2 are changed between the vicinity 12 and the intermediate portion 13 of the fastening bolt.
That is, by making the inner angle θ1 and the outer angle θ2 in the vicinity portion 12 of the fastening bolt larger than the values of the inner angle θ1 and the outer angle θ2 in the intermediate portion 13 of the fastening bolt, respectively, The rigidity of the annular protrusion 11 at the portion 12 can be made lower than the rigidity at the intermediate portion 13 of the fastening bolt.
As a result, the surface pressure applied to the top surface 11C in the vicinity 12 of the fastening bolt can be made equal to the surface pressure applied to the intermediate portion 13 of the fastening bolt, so that the surface pressure distribution applied to the top surface 11C is uniform. Can be.
Also in this case, at least one of the outer angle and the inner angle may be set large near the fastening bolt and small at a position away from the fastening bolt.
[0021]
In the above embodiment, the first to third configurations are used in combination and the shape is changed between the vicinity 12 of the fastening bolt and the intermediate portion 13 of the fastening bolt. The third configuration may be used alone, or two types of configurations may be combined.
[0022]
【The invention's effect】
As described above, according to the present invention, since the load applied to the top surface of the annular protrusion can be made uniform, the sealing performance of the metal gasket can be improved as compared with the prior art. The effect that the crack which had generate | occur | produced in the outer part of the top | upper surface in can be prevented is acquired.
[Brief description of the drawings]
FIG. 1 is a plan view showing a metal gasket of the present invention.
FIG. 2 is an enlarged cross-sectional view taken along the line II-II in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal gasket 2 Gasket board | substrate 3 Combustion chamber hole 11 Annular protrusion 11A Inner wall surface 11B Outer wall surface 11C Top surface t1, t2 Wall surface height R1a Inner board arc part R1b Outer board arc part R2a Inner top arc part R2b Outer top arc part r1a inner substrate radius of curvature r1b outer substrate radius of curvature r2a inner top radius of curvature r2b outer top radius of curvature θ1 inner angle θ2 outer angle

Claims

A combustion chamber hole formed in a metal gasket substrate in accordance with the cylinder bore, and an annular protrusion formed continuously in the circumferential direction of the combustion chamber hole in the gasket substrate and projecting in a U-shaped cross section; In the metal gasket provided with an inner wall surface on the combustion chamber hole side, an outer wall surface opposite to the combustion chamber hole side, and a top surface that connects both wall surfaces,
Set the height of the outer wall surface smaller than the height of the inner wall surface,
Further, the gasket substrate and the inner wall surface, and the gasket substrate and the outer wall surface are connected via an inner substrate arc portion and an outer substrate arc portion, respectively, and the curvature radius of the outer substrate arc portion is set to the inner substrate arc portion. Set larger than the radius of curvature of
Further, the inner wall surface and the top surface, and the outer wall surface and the top surface are connected via the inner top surface arc portion and the outer top surface arc portion, respectively, and the curvature radius of the outer top surface arc portion is set to the inside. A metal gasket characterized in that it is set larger than the radius of curvature of the top surface arc portion.

At least one of the height of the inner wall surface and the height of the outer wall surface is set low in the vicinity of the fastening bolt that connects the cylinder head and the cylinder block, and is set high at a position away from the fastening bolt. The metal gasket according to claim 1 .

The radius of curvature of at least one of the inner substrate arc portion, the outer substrate arc portion, the inner top surface arc portion, and the outer top surface arc portion is large in the vicinity of the fastening bolt that connects the cylinder head and the cylinder block. The metal gasket according to claim 1 or 2 , wherein the metal gasket is set small at a distant position.

A combustion chamber hole formed in a metal gasket substrate in accordance with the cylinder bore, and an annular protrusion formed continuously in the circumferential direction of the combustion chamber hole in the gasket substrate and projecting in a U-shaped cross section; In the metal gasket provided with an inner wall surface on the combustion chamber hole side, an outer wall surface opposite to the combustion chamber hole side, and a top surface that connects both wall surfaces,
Set the height of the outer wall surface smaller than the height of the inner wall surface,
The metal gasket is characterized in that an outer angle between the gasket substrate and the outer wall surface is set larger than an inner angle between the gasket substrate and the inner wall surface.

At least one of the height of the inner wall surface and the height of the outer wall surface is set low in the vicinity of the fastening bolt that connects the cylinder head and the cylinder block, and is set high at a position away from the fastening bolt. The metal gasket according to claim 4 .

Is at least one of the outer angle and an inner angle, claim, characterized in that large in the vicinity of the fastening bolts connecting the cylinder head and the cylinder block, is set smaller at a position away from the fastening bolts 4 Or the metal gasket of Claim 5 .

A combustion chamber hole formed in a metal gasket substrate in accordance with the cylinder bore, and an annular protrusion formed continuously in the circumferential direction of the combustion chamber hole in the gasket substrate and projecting in a U-shaped cross section; In the metal gasket provided with an inner wall surface on the combustion chamber hole side, an outer wall surface opposite to the combustion chamber hole side, and a top surface that connects both wall surfaces,
Set the height of the outer wall surface smaller than the height of the inner wall surface,
Further, the gasket substrate and the inner wall surface, and the gasket substrate and the outer wall surface are connected via an inner substrate arc portion and an outer substrate arc portion, respectively, and the curvature radius of the outer substrate arc portion is set to the inner substrate arc portion. Set larger than the radius of curvature of
Further, the inner wall surface and the top surface, and the outer wall surface and the top surface are connected via the inner top surface arc portion and the outer top surface arc portion, respectively, and the curvature radius of the outer top surface arc portion is set to the inside. Set larger than the radius of curvature of the top arc,
The metal gasket is characterized in that the outer angle between the gasket substrate and the outer wall surface is set larger than the inner angle between the gasket substrate and the inner wall surface.

At least one of the height of the inner wall surface and the height of the outer wall surface is set low in the vicinity of the fastening bolt that connects the cylinder head and the cylinder block, and is set high at a position away from the fastening bolt. The metal gasket according to claim 7 .

The radius of curvature of at least one of the inner substrate arc portion, the outer substrate arc portion, the inner top surface arc portion, and the outer top surface arc portion is large in the vicinity of the fastening bolt that connects the cylinder head and the cylinder block. The metal gasket according to claim 7 or 8 , wherein the metal gasket is set to be small at a distant position.

Is at least one of the outer angle and an inner angle, claim 7, characterized in that the increase in the vicinity of the fastening bolts connecting the cylinder head and the cylinder block, is set smaller at a position away from the fastening bolt The metal gasket according to claim 9 .

In the gasket substrate, a metal gasket according to any one of claims 1 to claim 10, characterized in that the bead portion which bulges the annular projection in the same direction so as to surround the annular projection is formed.