JP2004340315A

JP2004340315A - Metal seal

Info

Publication number: JP2004340315A
Application number: JP2003139843A
Authority: JP
Inventors: Tetsuya Ashida; 哲哉芦田; Hiroki Oida; 弘紀笈田; Takayoshi Mitsui; 孝禎三ツ井
Original assignee: Mitsubishi Cable Industries Ltd
Current assignee: Mitsubishi Cable Industries Ltd
Priority date: 2003-05-19
Filing date: 2003-05-19
Publication date: 2004-12-02
Anticipated expiration: 2023-05-19
Also published as: JP4299581B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal seal, exhibiting enough sealing performance and having low fastening force and large restoring amount. <P>SOLUTION: This metal seal is annular as a whole and interposed between first and second contact flat surface parts parallel to each other. The metal seal has an intermediate base part, a first contact projected part and a second contact projected part. The first contact projected part 11 is projected rather closer to the inside diameter and the second projected part 12 is projected rather closer to the outside diameter. In its applied and compressed state, the metal seal produces torsional elastic deformation around the intermediate base part 3. Further, the metal seal has first and second auxiliary projections 21, 22 respectively abutted on the first and second contact flat surface parts to prevent excessive torsional elastic deformation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、金属シールに関する。
【０００２】
【従来の技術】
真空、又は内圧外圧の固定フランジ用のシールとしては、従来、ゴムや樹脂等の様々な材料が使用されてきた。特に、高真空・高圧の内圧又は外圧用、高温・低温、及び、腐食性流体への適用等の過酷な条件下では、金属シールが用いられる場合が多い。
【０００３】
【発明が解決しようとする課題】
しかしながら、この金属シールには次のような問題がある。即ち、従来の金属シールは一般に締付力が高く、そのため、相手部材（シール取付部材）としてのフランジ等の肉厚を増加せねばならず、装置の重量増加及び容積（スペース）増加等の問題が発生する。
また、従来、横断面楕円形や円形の金属シールが使用されていた（図示省略）が、相互に平行な一対の平坦面の間に、このような楕円形や円形の金属シールを圧接状に装着した場合、平坦面との圧接シール部分で、局部的に塑性変形を生じ、平坦面───つまりフランジ等の相手部材───に損傷を与え、フランジ等の相手部材の再使用（繰返し使用）に関して問題を生じていた。また、保守・点検等の解体時に、高いメンテナンスコストとメンテナンス時間を要していた。
【０００４】
上述の横断面楕円形や円形の金属シールが相手部材の平坦面に損傷を与える理由は、この金属シールの剛性高さの故に、ほとんど弾性変形することができず、一対の平坦面が相互に接近しようとする方向の締付力をそのまま受けて、局部的に塑性変形（圧潰）を受けるためである。
要するに、従来の金属シールでは作成が容易で、締付力が小さく、かつ、弾性的復元量が大きく、相手部材（平坦面）を局部的に圧潰せず（損傷を与えない）という全ての条件を満足させ得るものが知られていなかった。
【０００５】
そこで、本発明者等は、図６に例示するような横断面形状の金属シール３０を、特願２００２−２１１０９７にて提案した。即ち、この金属シール３０は、相互に平行な第１平坦面部３１と第２平坦面部３２の間に介装され、全体が環状であり、横断面矩形状の中間基部３３と、第１平坦面部３１に当接する内径寄りの半円形の第１接触凸部３６と、第２平坦面部３２に当接する外径寄りの半円形の第２接触凸部３７とを、有し、そして、装着圧縮状態（使用状態）では、相互に接近する第１・第２平坦面部３１・３２から受ける押圧力Ｆ_１，Ｆ_２によって、中間基部３３を中心に捩れ弾性変形を生じ、その捩れ弾性変形に伴う弾性的反発力により、第１接触凸部３６は第１平坦面部３１に圧着・圧接し、かつ、第２接触凸部３７は第２平坦面部３２に圧着・圧接しして、密封（シール）作用をなさしめるものである。
【０００６】
この図６のように、締付力（矢印Ｆ_１，Ｆ_２参照）が小さく、復元性に優れた金属シールを提案したのであったが、流体圧力Ｐ…が高い使用条件───例えば１０ＭＰａ以上の圧力───では、図６（Ｂ）の矢印Ｚ方向に、第２接触凸部３７が第２平坦面部３２から浮上り、矢印Ｇ方向に流体洩れ（ブローバイ）を発生する虞のあることが、その後の本発明者等の試作実験等の検討の結果判明した。
即ち、図６（Ｂ）に示す如く、金属シール３０に高圧の流体圧力Ｐが作用すると、比較的小さな締付力（押圧力）Ｆ_１，Ｆ_２にて捩れ弾性変形中の金属シール３０は、図６（Ｂ）に示した実線から２点鎖線のように、簡単に矢印Ｚ方向に浮上る現象を生じ、矢印Ｇ方向へ流体洩れ（ブローバイ）を発生する。
【０００７】
本発明の目的は、（金属シールでありながら）締付力が小さく、復元性に優れ、相手部材としてのフランジ等の肉厚を薄くでき、装置の軽量化とコンパクト化を図り、しかも、高圧作用時に、ブローバイ等の流体洩れを有効に防止できて、優れた密封（シール）性を発揮する金属シールを提供することにある。
【０００８】
【課題を解決するための手段】
そこで、本発明は、相互に平行な第１接触平坦面部と第２接触平坦面部の間に介装される全体が環状の金属シールに於て、中間基部と、上記第１接触平坦面部に当接する内径寄りの第１接触凸部と、上記第２接触平坦面部に当接する外径寄りの第２接触凸部と、を備え、装着圧縮状態にて、上記第１・第２平坦面部から受ける押圧力によって上記中間基部を中心に捩れ弾性変形を生ずるように構成され、かつ、内径側圧力作用時に上記第１接触平坦面部に当接して過大捩れ弾性変形を防ぐ第１補助突起を外径寄りに有する。
【０００９】
また、相互に平行な第１接触平坦面部と第２接触平坦面部の間に介装される全体が環状の金属シールに於て、中間基部と、上記第１接触平坦面部に当接する内径寄りの第１接触凸部と、上記第２接触平坦面部に当接する外径寄りの第２接触凸部と、を備え、装着圧縮状態にて、上記第１・第２平坦面部から受ける押圧力によって上記中間基部を中心に捩れ弾性変形を生ずるように構成され、かつ、圧力作用時に上記第１・第２接触平坦面部に各々当接して過大捩れ弾性変形を防ぐ第１補助突起を外径寄り・内径寄りに有する。
【００１０】
また、相互に平行な第１接触平坦面部と第２接触平坦面部の間に介装される全体が環状の金属シールに於て、中間基部と、上記第１接触平坦面部に当接する内径寄りの第１接触凸部と、上記第２接触平坦面部に当接する外径寄りの第２接触凸部と、を備え、装着圧縮状態にて、上記第１・第２平坦面部から受ける押圧力によって上記中間基部を中心に捩れ弾性変形を生ずるように構成され、かつ、外径側圧力作用時に上記第２接触平坦面部に当接して過大捩れ弾性変形を防ぐ第２補助突起を内径寄りに有する。
【００１１】
【発明の実施の形態】
以下、図示の実施の形態に基づき、本発明を詳説する。
図１及び図２は、本発明に係る金属シール（メタルシール）Ｓの実施の一形態を示し、図１は自由状態（未装着状態）の断面正面図であり、図２は使用状態───装着圧縮状態───を示す要部断面説明図である。
【００１２】
この金属シールＳは、ステンレス鋼やばね用鋼やその他の金属から成り、切削や研削等の機械加工にて作製される。
この金属シールＳは、相互に平行な第１接触平坦面部１と第２接触平坦面部２の間に介装されるものであって、全体が円形，楕円，長円，略矩形等の環状である。横断面形状について説明すれば、略矩形（長方形）の中間基部３と、略半円形の第１接触凸部１１と第２接触凸部１２と、から成る。第１接触凸部１１は中間基部３の内径寄りに、第２接触凸部１２は中間基部３の外径寄りに、夫々配設される。
装着状態で、内径寄りの第１接触凸部１１は第１接触平坦面部１に当接し、外径寄りの第２接触凸部１２は第２接触平坦面部２に当接する。
【００１３】
図１の右半分、及び、図２に於て、２点鎖線によって、中間基部３と、第１・第２接触凸部１１，１２との境界線を示す。図示省略したが、装着未圧縮状態では、この中間基部３の（図の）上下の長辺側端面５，６は、フランジ等の取付部材（相手部材）７，８の前記第１・第２接触平坦面１，２と、平行状態である。なお、図示省略するが、上下の長辺側端面５，６の一方又は両方を、第１・第２接触平坦面１，２と平行でない状態（傾斜状）としても良い場合がある。その後、取付部材（相手部材）７，８が相互に接近してゆけば、図２に示した装着圧縮状態となる。図２の装着圧縮状態にて、第１・第２平坦面部１，２から受ける押圧力Ｆ_１，Ｆ_２によって中間基部３を中心に捩れ弾性変形を生じる。
【００１４】
そして、２１は小三角形状の第１補助突起であり、中間基部３の（図の上方の）端面５の外径寄りに配設されて、図２のように流体圧力Ｐによる圧力が作用した時（圧力作用時）に、この外径寄りの第１補助突起２１は第１接触平坦面部１に当接し、過大捩れ弾性変形を防ぐ。
また、２２は小三角形状の第２補助突起であり、中間基部３の（図の下方の）端面６の内径寄りに配設されて、図２のように圧力作用時に、この第２補助突起２２は第２接触平坦面部２に当接し、過大捩れ弾性変形を、同時に防ぐ作用をなしている。流体圧力Ｐが高いときに、上記第１補助突起２１・第２補助突起２２による過大捩れ弾性変形防止効果は特に発揮される。しかしながら、流体圧力Ｐが低圧のとき（又は真空）であっても、金属シールＳ自体がクリープ現象で変形することを、上記第１・第２補助突起２１，２２が防止できる。
【００１５】
横断面に於て、中間基部３の一端面５の内径寄りには第１接触凸部１１が、外径寄りには第１補助突起２１が、夫々突出状に、配設され、第１補助突起２１の高さ寸法（突出寸法）Ｈ_２１は、第１接触凸部１１の高さ寸法（突出寸法）Ｈ_１１よりも小さく設定されている。つまり、Ｈ_２１＜Ｈ_１１とする。
他方、中間基部３の他端面６の外径寄りには第２接触凸部１２が、内径寄りには第２補助突起２２が、夫々突出状に、配設され、第２補助突起２２の高さ寸法（突出寸法）Ｈ_２２は、第２接触凸部１２の高さ寸法（突出寸法）Ｈ_１２よりも小さく設定されている。つまり、Ｈ_２２＜Ｈ_１２とする。
【００１６】
このように、断面矩形状の中間基部３に対し、内径側と外径側に相互に（ラジアル方向に）位置をずらせて、かつ、軸心Ｌ方向に相反する方向に、第１接触凸部１１と第２接触凸部１２を突設している。かつ、第１補助突起２１と第２補助突起２２は、同時に、断面矩形状の中間基部３に対し、内径側と外径側に相互に（ラジアル方向に）位置をずらせて、かつ、軸心Ｌ方向に相反する方向に、突設する。しかも、断面矩形状の中間基部３の（内周面を成す）短辺９と略半円形の第１接触凸部１１とは（段差のない）連続状であり、かつ、断面小三角形状の第２補助突起２２は上記短辺９から折曲線状に連続形成されており、（段差がなく、）断面矩形状の中間基部３の角部に配設されている場合を示している。
【００１７】
さらに、断面矩形状の中間基部３の（外周面を成す）他の短辺１０と略半円形の第２接触凸部１２とは（段差のない）連続状であり、かつ、断面小三角形状の第１補助突起２１は上記短辺１０から折曲線状に連続形成されており、（段差がなく、）断面矩形状の中間基部３の角部に配設されている。このように、第１補助突起２１と第２補助突起２２とは、中間基部３の重心点に関して点対称位置にあるといえる。また、前述の第１接触凸部１１と第２接触凸部１２とは、上記重心点に関して点対称位置にあるといえる。
【００１８】
なお、図１と図２の実施の形態に於て、第１・第２補助突起２１，２２の位置を、短辺９又は短辺１０と折曲線状に連続する角位置とせず、中角基部３の上記角位置から、僅かに内側に移転させて、端面５，６から、突出状に設けるも、自由である（図示省略）。また、第１・第２補助突起２１，２２の形状としては図示の小三角形状以外に、半円形や半楕円形の先端丸味（アール部）を有する形状とするも自由である（図示省略）。
【００１９】
そして、図１に示した自由状態の金属シールＳを、第１・第２接触平坦面部１，２の間に装着して、この第１・第２接触平坦面部１，２を相互に接近させて、図２に示す装着圧縮状態に近づけてゆけば、一対の第１・第２接触平坦面部１，２から受ける押圧力Ｆ_１，Ｆ_２によって、この金属シールＳは中間基部３（の重心）を中心として、回転して（倒れて）捩れ弾性変形を生ずる。そして、第１・第２補助突起２１，２２を、夫々、第１・第２接触平坦面部１，２に軽く接触させるように、この第１・第２接触平坦面部１，２の相互間隔寸法Ｃを予め設定しておく。この図２に示した捩れ弾性変形の状態は、一対の第１・第２接触平坦面部１，２が相互に分離すれば、図１に示した元の状態───自由状態姿勢───に復元する。
【００２０】
そして、図２に於て、矢印Ｐで示したように、内径側圧力作用時に、第１接触平坦面１に第１補助突起２１が当接すると同時に、第２接触平坦面部２に第２補助突起２２が当接し、過大捩れ弾性変形を防ぎ、第２接触凸部１２が第２接触平坦面部２から遊離し（浮き上り）、図６（Ｂ）で既に述べた矢印Ｇ方向の流体洩れ（ブローバイ）を防止できる。
【００２１】
要するに本発明に係る金属シールＳでは、相手部材（取付部材）７，８の押圧力Ｆ_１，Ｆ_２を、巧妙に、中間基部３を中心に回転する───倒れる───捩れ弾性変形によって、柔軟に受け止め、かつ、第１・第２補助突起２１，２２を、夫々、相手部材（取付部材）７，８に軽く接触させて（図６に矢印Ｇで示した）流体洩れ・ブローバイを防止し、金属シールＳと第１・第２接触平坦面部１，２との接触面圧（当接面圧）を常に小さく保って、金属シールＳ及び第１・第２接触平坦面部１，２が局部的に塑性変形したり、損傷を受けることを、有効に防止できる。
【００２２】
ところで、図１と図２に示した実施の形態のものは、外径側圧力作用時にも有効であり、いわゆる内圧用と外圧用の両方に使用できる形状である。つまり、図２に於て、外径側から圧力流体が作用すれば、第２補助突起２２と第２接触平坦面部２との当接によって、金属シールＳ全体の捩りは阻止され、第１接触凸部１１と第１接触平坦面部１との分離が防がれて、そこからの流体洩れが防止できる。
【００２３】
次に、図３に示す他の実施の形態について説明する。この図３は既述の実施の形態を示す図２に代わる装着圧縮状態の断面図である。この図３に示した金属シールＳは、図２と図１に示した金属シールＳの第２補助突起２２を省略した構成であって、それ以外は同一符号は同様の構成であるので重複説明を省略する。
この図３の金属シールＳは、内径側圧力作用時に、第１接触平坦面部１に当接して過大捩れ弾性変形を防ぐ第１補助突起２１のみを外径寄りに有する形状である。即ち、内径側に圧力（矢印Ｐ参照）が作用した際に、図６（Ｂ）のように、矢印Ｚ方向に第２接触凸部３７───図３の第２接触凸部１２───が浮き上ることを防ぎ、矢印Ｇ方向への流体洩れを防止する内圧用である。
【００２４】
次に、図４に示す別の実施の形態について説明する。この図４は既述の図２に代わる装着圧縮状態の断面図であり、この図４のものは、図２と図１に示した金属シールＳの第１補助突起２１を省略した構成であって、それ以外は同一符号は同様の構成であるので、重複説明を省略する。
この図４の金属シールＳは、外径側圧力作用時に、第２接触平坦面部２に当接して過大捩れ弾性変形を防ぐ第２補助突起２２のみを内径寄りに有する形状である。即ち、外径側に圧力（矢印Ｐ参照）が作用した際に、第１接触凸部１１が第１接触平坦面部１から浮き上ることを防ぎ、その接触部（密封部）から、流体が内径方向へ洩れる（ブローバイする）ことを、防止する。つまり、外圧用の金属シールを示す。
【００２５】
図５の実線は比較例を示す断面図であって、点線は本発明の図１の場合を比較のために付記した断面図である。即ち、本発明の金属シールＳのように第１・第２補助突起２１，２２を設けない場合で、図２で述べたと同様の浮き上り防止及び流体洩れ防止作用を得るには、中間基部の厚さ寸法Ｔを実線のように増加せねばならない。このように大きな厚さ寸法Ｔでは、図２で示した押圧力Ｆ_１，Ｆ_２が、極端に増大する。つまり、低締付力という本発明に係る金属シールＳの利点が無くなることが分かる。言い換えれば、この図５から、本発明に係る金属シールＳは、低締付力───押圧力Ｆ_１，Ｆ_２が小さい───という利点を、そのまま残しつつ、図６（Ｂ）で述べた浮上り及び流体洩れを、防止している、優れた金属シールであるといえる。
【００２６】
なお、本発明に係る金属シールＳでは、補助突起２１，２２によって、取付部材７，８の相互間隔寸法Ｃの調整が可能となり、余剰な変形を抑えることができ、クリープ変形（捩り変形）を減少乃至防止できる。つまり、補助突起２１，２２が無い場合には、金属シールが大きい締付力で捩り変形の状態を長期間保つと、永久変形───クリープ変形───を発生してしまうが、本発明では、このような永久変形を防止できる。
【００２７】
このように、本発明に係る金属シールＳは、高圧環境下でも十分なシール性（密封性）を、長期間、安定して発揮できる。また、相手部材（取付部材）７，８に、過大捩り防止のために金属シールＳの一部に当接する段差加工等も、不要である。
なお、第１・第２補助突起２１，２２の形状は、小三角山形状の他に、小多角形状としたり、また、小半円形状や小楕円形状のアール状とするも、自由である。また、自由状態で、中間基部３が第１・第２接触平坦面部１，２と傾斜方向として、大きな回転（捩り）を可能としたり、また、端面５，６を凸曲面状、若しくは、凹曲面状とすることも可能である。また、第１・第２接触凸部１１，１２を多角形状とすることも自由である。
【００２８】
上述の図示の実施の形態によれば、横断面形状が直線部が多く、切削加工も容易かつ安価でありメタルＯリングでは加工が難しく高価であるような小さなサイズにも、十分対応できる。本金属シールＳは横断面形状がブロック型でズングリしているにかかわらず、倒れ（回転）による捩れ弾性変形等を複合的に行わせて、低締付力にて十分な密封性（シール性能）を発揮する。このような低締付力を活用して、従来のゴム製Ｏリングに代わるシール材として、高温や低温やプラズマ照射やオゾン雰囲気等の従来のＯリングでは適用できない過酷な条件下での適用が可能となる。
なお、材質としてＳＵＳ３１６Ｌダブルメルトは、カーボンなどの不純物が少なく、清浄度が要求される半導体製造装置として好適である。
【００２９】
本金属シールＳの表面について説明すると、▲１▼銀、金、銅、すず等のメッキ、▲２▼ＰＴＦＥ、ＦＥＰ等の各種樹脂被覆（コーティング）、▲３▼各種ゴム材料の被覆（コーティング）、▲４▼超研磨仕上げ、▲５▼切削又は研削加工又はプレス加工のまま、のいずれとするも自由である。また、被密封流体としては、上記表面被覆の有無及び材質にもよるが、真空、各種ガス（ＣＯ_２，Ｈ_２，Ｏ_２，ＮＨ_３，Ｈ_２Ｏ等）、各種液体（Ｈ_２Ｏ，Ｈ_２ＳＯ_４，ＨＣｌ等）のものに適用できる。いずれにせよ、本金属シールＳは、低締付力、及び、大きな弾性的復元量、取扱いの容易性、小部品点数、製作の容易性と安価である点で、優れたシールである。従って、装着される相手部材（フランジ等）７，８がセラミックのように脆い材質やアルミニウム等の軟らかい材質のものにも適用可能であり、また、半導体製造装置のようにプラズマやオゾン等が照射される部位にも適用でき、低温から高温までの広い温度領域にも対応できる。そして、潰しが利いて、広いセット高さ（符号Ｃ参照）の範囲で十分なシール性（密封性）を発揮するので、装着される相手部材（フランジ等）７，８の寸法精度や公差が粗くとも適用でき、深い溝でも浅い溝でも、共通の金属シールＳで対応可能となる場合もある。さらに、上下反転使用によって、長寿命化も図ることが容易である。
【００３０】
また、第１・第２接触凸部１１，１２を、図示の実施の形態のように、半円形乃至半楕円形とすれば、中間基部３を中心に回転して（倒れて）、捩れ弾性変形する場合、第１・第２接触凸部１１，１２は、広いセット高さの範囲で、常に安定して第１・第２平坦面部１，２に接触しつつ、全体にゆっくりと姿勢を変化させるので、優れた密封性能（シール性能）を備える。そして、反対側の端面５，６に突設した補助突起２２，２１によって、流体圧力Ｐが高い環境下でもブローバイ等の流体洩れが防止できて、高圧環境下でも優れた密封性能（シール性能）を確保できる。
【００３１】
【発明の効果】
本発明は、上述の構成により次のような著大な効果を奏する。
（請求項１，２，３によれば、）装着圧縮状態にて全体に捩れ弾性変形を生ずるように構成したので、低締付力で使用でき、取付部材（フランジ等）７，８が脆い材質や軟らかい材質にも適用できる。
また、金属Ｏリングでは制作が困難な外形寸法が１０ｍｍ未満の小型のシールとしても、比較的安価に制作可能なため、実用上優れた金属シールである。また、平坦面１，２の損傷も減少できる。
しかも、このような多くの利点を有しながら、高圧環境下でもブローバイ等の流体洩れを、補助突起２１及び／又は補助突起２２によって、防止できる。さらに、補助突起２１及び／又は補助突起２２によって、高圧、及び、低圧（真空）に於て長期使用期間後もクリープ変形を起こさず、長期間、優れた密封性能を維持できる。
（請求項２によれば、）内圧用と外圧用に兼用できる。
【図面の簡単な説明】
【図１】本発明の実施の一形態を示す自由状態の断面正面図である。
【図２】作用説明を兼ねた要部断面図である。
【図３】他の実施の形態を示す要部断面図である。
【図４】別の実施の形態を示す要部断面図である。
【図５】比較例と本発明の実施の形態とを比較対照して説明する断面図である。
【図６】本発明者等が既に出願した発明に係る金属シールを説明する要部断面図である。
【符号の説明】
１第１接触平坦面部
２第２接触平坦面部
３中間基部
１１第１接触凸部
１２第２接触凸部
２１第１補助突起
２２第２補助突起
Ｓ金属シール[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to metal seals.
[0002]
[Prior art]
Conventionally, various materials such as rubber and resin have been used as seals for fixing flanges for vacuum or internal and external pressures. In particular, under severe conditions such as high vacuum / high pressure internal or external pressure, high / low temperature, and application to corrosive fluids, metal seals are often used.
[0003]
[Problems to be solved by the invention]
However, this metal seal has the following problems. That is, the conventional metal seal generally has a high tightening force, so that the thickness of a flange or the like as a mating member (seal mounting member) must be increased, and the weight and volume (space) of the device are increased. Occurs.
Conventionally, a metal seal having an elliptical or circular cross section has been used (not shown), but such an elliptical or circular metal seal is pressed between a pair of flat surfaces parallel to each other. When mounted, plastic deformation occurs locally at the pressure-sealed part of the flat surface, damaging the flat surface {that is, the mating member such as a flange}, and reusing the mating member such as a flange (repeatedly). Use). Also, when dismantling such as maintenance and inspection, high maintenance cost and maintenance time were required.
[0004]
The reason that the above-mentioned metal seal having an elliptical or circular cross section damages the flat surface of the mating member is that the metal seal can hardly be elastically deformed due to the rigidity of the metal seal, and the pair of flat surfaces are mutually displaced. This is because plastic deformation (crushing) is locally caused by receiving the tightening force in the direction of approaching as it is.
In short, all the conditions that the conventional metal seal is easy to make, the tightening force is small, the amount of elastic restoration is large, and the mating member (flat surface) is not locally crushed (does not damage) There was no known one that could satisfy the above.
[0005]
Therefore, the present inventors have proposed a metal seal 30 having a cross-sectional shape as illustrated in FIG. 6 in Japanese Patent Application No. 2002-211097. That is, the metal seal 30 is interposed between the first flat surface portion 31 and the second flat surface portion 32 which are parallel to each other, and is entirely annular, and has an intermediate base portion 33 having a rectangular cross section and a first flat surface portion. 31 has a semicircular first contact convex portion 36 close to the inner diameter in contact with the inner surface 31 and a semicircular second contact convex portion 37 closer to the outer diameter in contact with the second flat surface portion 32. In the (use state), the pressing forces F ₁ and F ₂ received from the first and second flat surface portions 31 and 32 approaching each other cause torsional elastic deformation around the intermediate base 33, and the elasticity accompanying the torsional elastic deformation is generated. Due to the repulsive force, the first contact convex portion 36 is pressed and pressed against the first flat surface portion 31, and the second contact convex portion 37 is pressed and pressed against the second flat surface portion 32, thereby providing a sealing action. It is to make.
[0006]
As shown in FIG. 6, a metal seal having a small tightening force (see arrows F ₁ and F ₂ ) and excellent resilience has been proposed. At the pressure ─── described above, the second contact convex portion 37 floats up from the second flat surface portion 32 in the arrow Z direction in FIG. 6B, and there is a possibility that fluid leakage (blow-by) occurs in the arrow G direction. This has been found as a result of a study of a trial production experiment and the like by the present inventors.
That is, as shown in FIG. 6B, when a high fluid pressure P acts on the metal seal 30, the metal seal 30 undergoing the torsional elastic deformation with the relatively small tightening forces (pressing forces) F ₁ and F ₂ becomes strong. 6 (B), a phenomenon of easily floating in the arrow Z direction occurs as indicated by a two-dot chain line, and fluid leakage (blow-by) occurs in the arrow G direction.
[0007]
An object of the present invention is to reduce the tightening force (even though it is a metal seal), to provide excellent resilience, to reduce the thickness of a flange or the like as a mating member, to reduce the weight and size of the device, and to achieve high pressure. It is an object of the present invention to provide a metal seal that can effectively prevent fluid leakage such as blow-by during operation and exhibit excellent sealing performance.
[0008]
[Means for Solving the Problems]
In view of the above, the present invention provides a metal seal which is interposed between a first contact flat surface portion and a second contact flat surface portion, which are parallel to each other, and which contacts the intermediate base portion and the first contact flat surface portion. A first contact convex portion closer to the inner diameter and a second contact convex portion closer to the outer diameter contacting the second contact flat surface portion to receive from the first and second flat surface portions in a mounted compressed state; A first auxiliary projection configured to generate a torsional elastic deformation around the intermediate base portion by a pressing force and abutting against the first contact flat surface portion to prevent excessive torsional elastic deformation when an inner diameter side pressure is applied, to an outer diameter. To have.
[0009]
Further, in the annular metal seal interposed between the first contact flat surface portion and the second contact flat surface portion, which are parallel to each other, an intermediate base portion and an inner diameter close to the first contact flat surface portion are brought into contact. A first contact protruding portion, and a second contact protruding portion close to an outer diameter that comes into contact with the second contact flat surface portion, and the pressing force received from the first and second flat surface portions in a mounted and compressed state. First auxiliary projections configured to cause torsional elastic deformation around the intermediate base portion and abutting against the first and second contact flat surface portions when pressure is applied to prevent excessive torsional elastic deformation are provided near the outer diameter and the inner diameter. Have closer.
[0010]
Further, in the annular metal seal interposed between the first contact flat surface portion and the second contact flat surface portion, which are parallel to each other, an intermediate base portion and an inner diameter close to the first contact flat surface portion are brought into contact. A first contact protruding portion, and a second contact protruding portion close to an outer diameter that comes into contact with the second contact flat surface portion, and the pressing force received from the first and second flat surface portions in a mounted and compressed state. A second auxiliary projection, which is configured to cause torsional elastic deformation around the intermediate base portion and which comes into contact with the second contact flat surface portion when an outer diameter side pressure is applied to prevent excessive torsional elastic deformation, is provided near the inner diameter.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
1 and 2 show an embodiment of a metal seal (metal seal) S according to the present invention. FIG. 1 is a sectional front view of a free state (unmounted state), and FIG. It is principal part sectional explanatory drawing which shows {attachment compression state}.
[0012]
The metal seal S is made of stainless steel, spring steel, or another metal, and is manufactured by machining such as cutting and grinding.
The metal seal S is interposed between the first contact flat surface portion 1 and the second contact flat surface portion 2 which are parallel to each other, and is entirely annular, such as a circle, an ellipse, an oval, and a substantially rectangle. is there. Describing the cross-sectional shape, it comprises a substantially rectangular (rectangular) intermediate base portion 3 and a substantially semicircular first contact convex portion 11 and a second contact convex portion 12. The first contact projection 11 is disposed near the inner diameter of the intermediate base 3, and the second contact projection 12 is disposed near the outer diameter of the intermediate base 3.
In the mounted state, the first contact convex portion 11 near the inner diameter contacts the first contact flat surface portion 1, and the second contact convex portion 12 near the outer diameter contacts the second contact flat surface portion 2.
[0013]
In the right half of FIG. 1 and in FIG. 2, the two-dot chain line indicates the boundary between the intermediate base 3 and the first and second contact projections 11, 12. Although not shown, in the uncompressed state of mounting, the upper and lower long side end surfaces 5 and 6 of the intermediate base 3 (shown in the figure) are connected to the first and second mounting members (counterpart members) 7 and 8 such as flanges. It is in parallel with the contact flat surfaces 1 and 2. Although not shown, one or both of the upper and lower long side end surfaces 5 and 6 may not be parallel to the first and second contact flat surfaces 1 and 2 (inclined). Thereafter, when the mounting members (counterpart members) 7 and 8 approach each other, the mounted and compressed state shown in FIG. 2 is obtained. In the mounted and compressed state of FIG. 2, torsional elastic deformation is generated around the intermediate base 3 by the pressing forces F ₁ and F ₂ received from the first and second flat surfaces 1 and ₂ .
[0014]
Reference numeral 21 denotes a small triangular first auxiliary projection, which is disposed near the outer diameter of the end face 5 (upper part in the figure) of the intermediate base part 3 and is acted on by the fluid pressure P as shown in FIG. At the time (at the time of pressure action), the first auxiliary projection 21 near the outer diameter comes into contact with the first contact flat surface portion 1 to prevent excessive torsional elastic deformation.
Reference numeral 22 denotes a small triangular second auxiliary projection, which is disposed near the inner diameter of the end face 6 (at the bottom in the figure) of the intermediate base portion 3 and, when pressure is applied as shown in FIG. Numeral 22 abuts on the second contact flat surface portion 2 and functions to prevent excessive torsional elastic deformation at the same time. When the fluid pressure P is high, the effect of the first auxiliary projection 21 and the second auxiliary projection 22 to prevent excessive torsional elastic deformation is particularly exhibited. However, even when the fluid pressure P is low (or vacuum), the first and second auxiliary projections 21 and 22 can prevent the metal seal S itself from being deformed by the creep phenomenon.
[0015]
In the cross section, the first contact projection 11 is provided near the inner diameter of the one end face 5 of the intermediate base 3, and the first auxiliary protrusion 21 is provided near the outer diameter in a protruding manner. height of the projection 21 (projection _{dimension) H 21} is set smaller than the height (protruding _{dimension) H 11} of the first contact protrusions 11. That is, H ₂₁ <H ₁₁ is satisfied.
On the other hand, a second contact projection 12 is provided on the other end surface 6 of the intermediate base 3 near the outer diameter, and a second auxiliary projection 22 is provided on the inner diameter near the inner diameter. sized (protruding _{dimension) H 22} is set smaller than the height (protruding _{dimension) H 12} of the second contact protrusions 12. That is, H ₂₂ <H ₁₂ .
[0016]
As described above, the first contact convex portion is displaced from each other (in the radial direction) on the inner diameter side and the outer diameter side with respect to the intermediate base portion 3 having a rectangular cross section, and in the direction opposite to the axis L direction. 11 and the second contact convex portion 12 are protruded. Further, the first auxiliary projection 21 and the second auxiliary projection 22 are simultaneously displaced (in the radial direction) toward the inner diameter side and the outer diameter side with respect to the intermediate base 3 having a rectangular cross section, and It protrudes in the direction opposite to the L direction. Moreover, the short side 9 (forming the inner peripheral surface) of the intermediate base 3 having a rectangular cross section and the substantially semicircular first contact convex portion 11 are continuous (without steps) and have a small triangular cross section. The second auxiliary projection 22 is formed continuously from the short side 9 in a bent curve shape, and is disposed at a corner of the intermediate base 3 having a rectangular cross section (without a step).
[0017]
Further, the other short side 10 (forming the outer peripheral surface) of the intermediate base portion 3 having a rectangular cross section and the substantially semicircular second contact convex portion 12 are continuous (without a step) and have a small triangular cross section. The first auxiliary projection 21 is formed continuously from the short side 10 in a bent curve shape, and is disposed at a corner of the intermediate base 3 having a rectangular cross section (without a step). Thus, it can be said that the first auxiliary protrusion 21 and the second auxiliary protrusion 22 are at point-symmetric positions with respect to the center of gravity of the intermediate base 3. In addition, it can be said that the first contact protrusion 11 and the second contact protrusion 12 are at point-symmetric positions with respect to the center of gravity.
[0018]
In the embodiment shown in FIGS. 1 and 2, the positions of the first and second auxiliary projections 21 and 22 are not set to be corner positions that are continuous with the short side 9 or the short side 10 in a bent line shape, but are set to the middle angle. It is also possible to move the base portion 3 slightly inward from the above-mentioned angular position and to protrude from the end surfaces 5 and 6 (not shown). The shape of the first and second auxiliary projections 21 and 22 may be a shape having a semi-circular or semi-elliptical rounded tip (R) in addition to the small triangular shape shown in the figure (not shown). .
[0019]
Then, the metal seal S in the free state shown in FIG. 1 is mounted between the first and second contact flat surface portions 1 and 2 to bring the first and second contact flat surface portions 1 and 2 closer to each other. ₂ , the metal seal S is pressed by the pressing forces F ₁ and F ₂ received from the pair of first and second contact flat surface portions 1 and 2 to move the metal seal S to the center of gravity of the intermediate base portion 3. ), It rotates (falls down) to produce torsional elastic deformation. The distance between the first and second contact flat surface portions 1 and 2 is set such that the first and second auxiliary protrusions 21 and 22 lightly contact the first and second contact flat surface portions 1 and 2, respectively. C is set in advance. The state of the torsional elastic deformation shown in FIG. 2 is the original state shown in FIG. 1 {free state posture} if the pair of first and second contact flat surface portions 1 and 2 are separated from each other. To restore.
[0020]
Then, as shown by an arrow P in FIG. 2, the first auxiliary projection 21 abuts on the first contact flat surface 1 and the second auxiliary flat surface portion 2 at the same time when the inner side pressure is applied. The projections 22 come into contact with each other to prevent excessive torsional elastic deformation, the second contact projections 12 are separated from the second contact flat surface portion 2 (lift), and the fluid leakage in the direction of the arrow G already described with reference to FIG. Blow-by).
[0021]
In short, in the metal seal S according to the present invention, the pressing forces F ₁ , F ₂ of the mating members (mounting members) 7, 8 are cleverly rotated around the intermediate base 3 {tilting} torsional elastic deformation. The first and second auxiliary projections 21 and 22 are lightly contacted with the mating members (mounting members) 7 and 8 respectively (indicated by an arrow G in FIG. 6), thereby allowing fluid leakage and blow-by. And the contact surface pressure (contact surface pressure) between the metal seal S and the first and second contact flat surface portions 1 and 2 is always kept small, so that the metal seal S and the first and second contact flat surface portions 1 and 2 are kept at a low level. 2 can be effectively prevented from being locally plastically deformed or damaged.
[0022]
By the way, the embodiment shown in FIGS. 1 and 2 is effective even when the outer diameter side pressure is applied, and has a shape which can be used for both so-called internal pressure and external pressure. That is, in FIG. 2, when the pressure fluid acts from the outer diameter side, the contact between the second auxiliary protrusion 22 and the second contact flat surface portion 2 prevents the entire metal seal S from being twisted, and the first contact is prevented. Separation between the convex portion 11 and the first contact flat surface portion 1 is prevented, and fluid leakage therefrom can be prevented.
[0023]
Next, another embodiment shown in FIG. 3 will be described. FIG. 3 is a cross-sectional view of the above-described embodiment in a mounted and compressed state instead of FIG. The metal seal S shown in FIG. 3 has a configuration in which the second auxiliary projection 22 of the metal seal S shown in FIGS. Is omitted.
The metal seal S in FIG. 3 has a shape in which only the first auxiliary projection 21 that abuts on the first contact flat surface portion 1 to prevent excessive torsional elastic deformation when the inner diameter side pressure is applied is located closer to the outer diameter. That is, when pressure (see arrow P) acts on the inner diameter side, as shown in FIG. 6B, the second contact convex portion 37 {the second contact convex portion 12 in FIG. It is for internal pressure that prevents ─ from floating and prevents fluid leakage in the direction of arrow G.
[0024]
Next, another embodiment shown in FIG. 4 will be described. FIG. 4 is a cross-sectional view of the mounted and compressed state in place of FIG. 2 described above. FIG. 4 is a configuration in which the first auxiliary projection 21 of the metal seal S shown in FIGS. 2 and 1 is omitted. Otherwise, the same reference numerals have the same configuration, and a duplicate description will be omitted.
The metal seal S of FIG. 4 has a shape in which only the second auxiliary projection 22 that abuts on the second contact flat surface portion 2 to prevent excessive torsional elastic deformation when the outer diameter side pressure is applied is located closer to the inner diameter. That is, when a pressure (see arrow P) acts on the outer diameter side, the first contact convex portion 11 is prevented from floating from the first contact flat surface portion 1, and the fluid flows from the contact portion (sealing portion) to the inner diameter. Leakage (blow-by) in the direction is prevented. That is, a metal seal for external pressure is shown.
[0025]
The solid line in FIG. 5 is a cross-sectional view showing a comparative example, and the dotted line is a cross-sectional view in which the case of FIG. 1 of the present invention is added for comparison. That is, in a case where the first and second auxiliary projections 21 and 22 are not provided as in the metal seal S of the present invention, in order to obtain the same floating prevention and fluid leakage prevention as described in FIG. The thickness dimension T must be increased as shown by the solid line. With such a large thickness dimension T, the pressing forces F ₁ and F ₂ shown in FIG. 2 increase extremely. That is, it is understood that the advantage of the metal seal S according to the present invention, that is, the low tightening force, is lost. In other words, from FIG. 5, the metal seal S according to the present invention has the advantage of a low tightening force {the pressing forces F ₁ and F ₂ are small} and the metal seal S in FIG. It can be said that this is an excellent metal seal that prevents the above-mentioned floating and fluid leakage.
[0026]
In the metal seal S according to the present invention, the auxiliary projections 21 and 22 allow the adjustment of the mutual spacing dimension C between the mounting members 7 and 8, thereby suppressing excessive deformation and reducing creep deformation (torsional deformation). It can be reduced or prevented. That is, when the metal seals are not torsionally deformed for a long time with a large tightening force without the auxiliary projections 21 and 22, permanent deformation {creep deformation} occurs. Then, such permanent deformation can be prevented.
[0027]
As described above, the metal seal S according to the present invention can exhibit a sufficient sealing property (sealing property) stably for a long period of time even under a high-pressure environment. Further, it is not necessary to form a step on the mating members (mounting members) 7 and 8 to abut a part of the metal seal S to prevent excessive twisting.
The shape of the first and second auxiliary projections 21 and 22 is not limited to a small triangular mountain shape but may be a small polygonal shape or a small semicircular shape or a small elliptical shape. Further, in the free state, the intermediate base portion 3 can be rotated (twisted) with the first and second contact flat surface portions 1 and 2 as an inclined direction, and the end surfaces 5 and 6 can be convexly curved or concave. It may be curved. In addition, the first and second contact projections 11 and 12 may be freely formed in a polygonal shape.
[0028]
According to the illustrated embodiment described above, the cross-sectional shape has many linear portions, cutting is easy and inexpensive, and it can sufficiently cope with a small size that is difficult and expensive to process with a metal O-ring. Regardless of the block shape of the metal seal S, the torsion elastic deformation and the like caused by falling down (rotation) are performed in a complex manner regardless of the block shape of the block shape, and sufficient sealing performance with low tightening force (seal performance) ). Utilizing such a low tightening force, it can be used as a sealing material to replace conventional rubber O-rings under severe conditions that cannot be applied with conventional O-rings such as high temperature, low temperature, plasma irradiation and ozone atmosphere. It becomes possible.
In addition, SUS316L double melt as a material is suitable as a semiconductor manufacturing apparatus which has few impurities such as carbon and requires cleanliness.
[0029]
The surface of the present metal seal S will be described as follows: (1) plating of silver, gold, copper, tin, etc., (2) coating of various resins such as PTFE and FEP, and (3) coating (coating) of various rubber materials. , (4) super-polishing finish, (5) cutting, grinding or pressing as it is. The sealed fluid may be vacuum, various gases (CO ₂ , H ₂ , O ₂ , NH ₃ , H ₂ O, etc.), various liquids (H ₂ O, H ₂ SO ₄ , HCl, etc.). In any case, the present metal seal S is an excellent seal in that it has a low tightening force, a large amount of elastic restoration, easy handling, small number of parts, easy manufacturing, and low cost. Accordingly, the mating members (flanges, etc.) 7 and 8 to be mounted can be applied to a brittle material such as ceramic or a soft material such as aluminum, and can be irradiated with plasma or ozone as in a semiconductor manufacturing apparatus. It can be applied to a wide range of temperatures from low to high. Since it is crushable and exhibits sufficient sealing properties (sealability) in a wide range of set heights (see symbol C), dimensional accuracy and tolerance of mating members (flanges, etc.) 7 and 8 to be mounted are reduced. Even if it is rough, it can be applied, and it may be possible to use a common metal seal S for both deep and shallow grooves. Further, it is easy to extend the service life by using the upside down.
[0030]
Further, if the first and second contact projections 11 and 12 are formed in a semicircular or semielliptical shape as in the illustrated embodiment, the first and second contact projections 11 and 12 rotate (fall down) around the intermediate base 3 and have torsional elasticity. In the case of deformation, the first and second contact projections 11 and 12 always slowly and stably contact the first and second flat surface portions 1 and 2 over a wide set height range. Since it changes, it has excellent sealing performance (seal performance). The auxiliary projections 22 and 21 projecting from the opposite end surfaces 5 and 6 can prevent fluid leakage such as blow-by even in an environment where the fluid pressure P is high, and provide excellent sealing performance (sealing performance) even in a high-pressure environment. Can be secured.
[0031]
【The invention's effect】
The present invention has the following significant effects by the above configuration.
(According to Claims 1, 2, and 3) Since it is configured such that torsion elastic deformation is generated as a whole in a mounted and compressed state, it can be used with a low tightening force, and the mounting members (flanges and the like) 7, 8 are fragile. It can be applied to materials and soft materials.
Further, even a small seal having an external dimension of less than 10 mm, which is difficult to produce with a metal O-ring, can be produced relatively inexpensively, and is a practically excellent metal seal. Also, damage to the flat surfaces 1 and 2 can be reduced.
Moreover, while having many of these advantages, leakage of fluid such as blow-by can be prevented by the auxiliary projections 21 and / or 22 even under a high-pressure environment. Furthermore, the auxiliary projections 21 and / or the auxiliary projections 22 can maintain excellent sealing performance for a long period of time without causing creep deformation even after a long use period under high pressure and low pressure (vacuum).
(According to claim 2), it can be used for both internal pressure and external pressure.
[Brief description of the drawings]
FIG. 1 is a sectional front view of a free state showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part that also serves as an explanation of the operation.
FIG. 3 is a cross-sectional view of a main part showing another embodiment.
FIG. 4 is a cross-sectional view of a main part showing another embodiment.
FIG. 5 is a cross-sectional view illustrating a comparative example and an embodiment of the present invention in comparison with each other.
FIG. 6 is a cross-sectional view of a principal part explaining a metal seal according to the invention which the present inventors have already applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st contact flat surface part 2 2nd contact flat surface part 3 Intermediate base 11 1st contact convex part 12 2nd contact convex part 21 1st auxiliary protrusion 22 2nd auxiliary protrusion S Metal seal

Claims

The intermediate base portion (3) and the first contact flat surface are disposed in a generally annular metal seal interposed between the first contact flat surface portion (1) and the second contact flat surface portion (2) which are parallel to each other. A first contact projection (11) near the inner diameter contacting the surface portion (1) and a second contact projection (12) near the outer diameter contacting the second contact flat surface portion (2). In a compressed state, the pressing force received from the first and second flat surface portions (1) and (2) is configured to cause torsion elastic deformation around the intermediate base portion (3), and when the inner diameter side pressure acts. A metal seal having a first auxiliary projection (21) near an outer diameter, which abuts on the first contact flat surface portion (1) to prevent excessive torsional elastic deformation.

The intermediate base portion (3) and the first contact flat surface are disposed in a generally annular metal seal interposed between the first contact flat surface portion (1) and the second contact flat surface portion (2) which are parallel to each other. A first contact projection (11) near the inner diameter contacting the surface portion (1) and a second contact projection (12) near the outer diameter contacting the second contact flat surface portion (2). In a compressed state, a pressing force received from the first and second flat surface portions (1) and (2) is configured to cause torsion elastic deformation around the intermediate base portion (3), and the first and second flat surface portions (1) and (2) are pressed when the pressure is applied. Metal seals having first auxiliary projections (21) and (22), which abut against respective first and second contact flat surface portions (1) and (2) to prevent excessive torsional elastic deformation, near an outer diameter and an inner diameter. .

The intermediate base portion (3) and the first contact flat surface are disposed in a generally annular metal seal interposed between the first contact flat surface portion (1) and the second contact flat surface portion (2) which are parallel to each other. A first contact projection (11) near the inner diameter contacting the surface portion (1) and a second contact projection (12) near the outer diameter contacting the second contact flat surface portion (2). In a compressed state, a pressing force received from the first and second flat surface portions (1) and (2) causes torsion elastic deformation around the intermediate base portion (3), and an outer diameter side pressure action A metal seal characterized by having a second auxiliary projection (22) near the inner diameter that sometimes comes into contact with the second contact flat surface portion (2) to prevent excessive torsional elastic deformation.