JP2004076870A

JP2004076870A - Sealing structure of high-pressure hydrogen gas, and seal

Info

Publication number: JP2004076870A
Application number: JP2002239100A
Authority: JP
Inventors: Hiroshi Aoshiba; 青柴　浩史; Yasushi Kano; 加納　康司
Original assignee: Mitsubishi Cable Industries Ltd
Current assignee: Mitsubishi Cable Industries Ltd
Priority date: 2002-08-20
Filing date: 2002-08-20
Publication date: 2004-03-11
Anticipated expiration: 2022-08-20
Also published as: JP4198954B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure capable of enduring sealing of high-pressure hydrogen gas. <P>SOLUTION: An opening groove part 3 in the radial direction is formed by an inner lip part 1 and an outer lip part 2. A small protrusion 13 is integrally formed with the outer peripheral surface 8a of a shaft 8 for preventing the seal from slipping off. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、高圧水素ガス密封構造及びそれ用のシールに関する。
【０００２】
【従来の技術】
最近、水素ガス燃料電池車の研究開発が進展しているが、燃料の高圧水素ガスを送る配管途中に、レギュレータ電磁弁等の弁類が用いられ、このような高圧水素ガス用の弁類に適応できる密封用シールとして、従来、適切なものがなかった。
【０００３】
【発明が解決しようとする課題】
一般的な流体用弁類のシールとしては、図９に示すように、ゴム製Ｏリング４１が、使用され、スプール（軸）４２に一体に形成された凹周溝４３───いわゆる一体溝───に、２点鎖線にて示す如くＯリング４１を弾性的に拡径しつつ基本径端部４４を超えて、装着していた。なお、４５は弁本体（ハウジング又はボディとも呼ぶ）であり、その孔部４５ａの内周面にＯリング４１が接触（摺接）する。
【０００４】
上述の一体溝とする理由は、分割溝構造とした場合には、図９の基本径端部を別部品としてネジやボルトやスナップリング等で止着するため、スペース的に大きくなって、弁類の容積が増大する等の問題があるからである。
しかしながら、被密封用流体が上記水素ガス燃料電池車であると、例えば５０ＭＰａと高圧となり、弁類のＯＮ−ＯＦＦ作動時で圧力変動もあって、上述のゴム製Ｏリング４１ではブリスタを発生する虞があった。
また、金属（メタル）製Ｏリングは、一体溝構造では、図９の２点鎖線のように拡径（引き伸ばし）ができないので装着できない。かつ、スプール（軸）４２が（僅小寸法）軸心方向に往復動するため、孔部４５ａの摩耗及び金属製Ｏリングの摩耗が著しく、使用に適さない。
そこで、本発明の目的は、上述のような自動車用燃料の高圧水素ガスの圧力制御を行うレギュレータ電磁弁等の弁類に適用可能であって、かつ、構造が簡素でコンパクトである密封構造を提供することにある。さらに、従来の前記ブリスタが発生せず、高圧水素ガスの外部漏洩が僅少で、かつ、長い寿命を有するシール及び密封構造を提供することを、他の目的とする。
【０００５】
【課題を解決するための手段】
本発明の高圧水素ガス密封構造は、内リップ部と外リップ部によって軸心一方向に開口溝部を形成した樹脂製シール本体と、該開口溝部内に設けられたバネと、から成るシールを、ハウジング孔部と軸との間に形成された収納凹所に装着した密封構造に於て、上記軸には、上記収納凹所の奥底面を形成する段付面が形成され、上記シールの軸心方向寸法よりも大きい寸法だけ上記段付面から離れた位置に、シール抜け止め用小凸条を上記軸の外周面に、一体に形成したものである。
【０００６】
また、上記シール抜け止め用小凸条の外径寸法を、上記軸が上記収納凹所の内周面を形成する部位の外径寸法の　１０４％〜　１２５％に設定するのが好ましい。
また、本発明の高圧水素ガス用シールは、内リップ部が、シール用突起と、軸の一部（小凸条）に係止可能な係止用突起を有する。そして、上記シール本体の開口溝部の奥側の底壁部の肉厚寸法を、上記シール本体の軸心方向寸法の３５％〜５０％に設定するのが好ましい。
【０００７】
また、開口溝部を開口方向に弾発付勢する上記バネの軸心方向作用位置と、上記内リップ部のシール用突起及び上記外リップ部のシール用突起の頂部の軸心方向位置を、一致させる。
そして、シール本体の材質が変性ＰＴＦＥであり、かつ、バネの材質がＮｉ−Ｃｒ系の耐食合金であるのが望ましい。
【０００８】
【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〜図３に本発明の実施の一形態を示し、図２は自由状態のシールＳの断面図であり、図３は装着（使用）箇所を例示する断面図であり、図１は、このシールＳと装着（使用）箇所との位置関係及び寸法関係を説明する図である。
シールＳは、内リップ部１と外リップ２部を有し、この内外リップ部１，２によって軸心一方向に開口溝部３を形成した横断面略Ｕ字型形状の樹脂製シール本体４と、この開口溝部３内に設けられた横断面略Ｕ字型のバネ５と、から構成される。
【０００９】
高圧水素ガスを制御するレギュレータ電磁弁や、その他、切換弁や流量制御弁等の弁類のハウジング（ボディ）６の孔部７と、スプールや弁棒（弁本体）等の軸８との間に形成された収納凹所９に、上記シールＳが装着される。
この軸８は、収納凹所９の低圧側の奥底面を形成する段付面１０が形成され、上記孔部７よりも僅かに小さい外径寸法Ｄ_０　の大径部（ランド部）１１と、上記内リップ部１が摺接（接触）する小径部１２が、上記段付面１０にて区画形成されている。
【００１０】
シールＳの軸心方向寸法Ｈよりも僅かに大きい軸心方向寸法Ｈ_０　だけ、段付面１０から離れた位置に、シール抜け止め用小凸条１３を、軸８の外周面８ａに、一体に形成する。具体的には、この小凸条１３は、小径部１２の外周面に突出状に一体形成された略不等辺三角形状であって、小径部１２の先端面１４側は、緩やかなテーパ面（傾斜面）１３ａであり、段付面１０側は軸８の軸心１５と略直交方向乃至急な勾配面若しくは小アール状とした係止面１３ｂである。
【００１１】
上記軸心方向寸法Ｈ_０　は、この係止面１３ｂから、段付面１０までの間隔寸法を指すものとする。そして、次式▲１▼が成立するように、軸心方向寸法Ｈ_０　を設定する。
１．１０×Ｈ≦Ｈ_０　≦１．２５×Ｈ　　　▲１▼
言い換えると、このシールＳは、軸８の軸心方向の動きに対してルーズであって余裕がある。
【００１２】
そして、シール抜け止め用小凸条１３の外径寸法Ｄ_１３を、上記軸８が収納凹所９の内周面を形成する部位の外径寸法Ｄ_１２の　１０４％〜　１２５％に設定する。特に、　１０５％〜　１１０％が望ましい。
これを式で示せば、次式▲２▼▲３▼のようになる。
１．０４×Ｄ_１２≦Ｄ_１３≦１．２５×Ｄ_１２　　　▲２▼
望ましくは、
１．０５×Ｄ_１２≦Ｄ_１３≦１．１０×Ｄ_１２　　　　▲３▼
なお、上述の軸８が収納凹所９の内周面を形成する部位とは、具体的には、小径部１２が相当している。
【００１３】
ところで、シールＳについて詳しく説明すると、シール本体４の材質としては、変性ＰＴＦＥが好ましく、バネ５の材質としてはＮｉ−Ｃｒ系の耐食合金が好ましい。
【００１４】
本発明に於て、変性ＰＴＦＥとは、テトラフルオロエチレンとパーフルオロ（アルキルビニルエーテル）との共重量体を意味するものとする。このような変性ＰＴＦＥの一例としては、一般式Ｒ−Ｏ−ＣＦ＝ＣＦ_２　で表されるパーフルオロ（アルキルビニルエーテル）の少なくとも１種とテトラフルオロエチレンとの共重合体が用いられる。またパーフルオロ（アルキルビニルエーテル）としては、上記式中のＲが炭素数３〜４のパーブルオロアルキル基であるもの、例えばパーフルオロ（プロピルビニルエーテル）、パーフルオロ（ブチルビニルエーテル）などが好ましい。さらにパーフルオロ（アルキルビニルエーテル）を　０．１〜１０重量％、好ましくは　０．５〜５重量％含有するのが好ましい。
【００１５】
そして、充填材を混入させない材質が望ましい。その理由は、例えば５０ＭＰａ等の高圧水素ガスの圧力が作用すると、充填材入りＰＴＦＥでは、内外リップ部１，２の表面が粗くなり（微小凹凸が生じ）、軸８の外周面及び孔部７の内周面に接触する部位（接面）から高圧水素ガスが漏れ易くなる。
【００１６】
バネ５に適用するＮｉ−Ｃｒ系の耐食合金としては、Ｎｉ７６％，Ｃｒ１６％，Ｆｅ８％の耐食合金インコネル（登録商標）が水素ガスに対する耐食性の点で優れている。
【００１７】
そして、内リップ部１はシール用突起１６と、軸８の小径部１２の小凸条１３の係止面１３ｂに係止可能な係止用突起１７を、有する。
係止用突起１７は、内リップ部１の先端面１８と連続平坦面状に形成された軸心直交面と、シール本体４の厚肉の底壁部１９側へしだいに拡径する勾配面２０と、を有する三角山型である。
【００１８】
シール用突起１６は、軸心直交面２１と、底壁部１９側へしだいに拡径する勾配面２２と、を有する三角山形である。両突起１６，　１７はその内径寸法を相互に同一に設定し、先端面１８寄りの突起１７は、図１の状態のように軸心方向に余裕をもってルーズに収納凹所９に装着された状態で、シール本体４が抜け出ようとした場合に、軸８（小径部１２）のシール抜け止め用小凸条１３の係止面１３ｂに、係止して、確実に抜け止めされる。かつ、この係止用突起１７は、隣接されたシール用突起１６と同様にシール（密封）作用もはたす。言い換えれば、シール本体４は内周面側に、２重シールリップ（シール突起）を備えている。
【００１９】
他方、外リップ部２は、頂点から先端と基端方向へ緩やかな勾配面を有する低三角形状のシール用突起２３を有する。図２から分かるように、外リップ部２側のシール用突起２３と、内リップ部１側のシール用突起１６は、軸心１５と直交する同一平面上に配設され、さらに、開口溝部３を開口方向に弾発付勢するバネ５の軸心方向作用位置と、両シール用突起１６，２３の頂部（頂点）の軸心方向位置を、一致させている。
【００２０】
バネ５は横断面Ｕ字型であって、先端側───高圧水素ガス収納空室２４側───へ開口状となるように、シール本体４の開口溝部３へ組込まれている。横断面Ｕ字型の開口端部２５，２５が内外リップ部１，２に接触して弾発的に押圧する軸心方向位置が、前記軸心方向作用位置であり、結局、軸心１５と直交する一平面上に、バネ５の作用位置（開口端部２５，２５）、及び、内外のシール用突起１６，　２３の頂部（頂点）が、配設される。
これによって、バネ５の弾発付勢力が、直接的かつ有効に、シール用突起１６，　２３の相手部材───軸８の外周面及び孔部７内周面───への接触面圧増大に寄与できて、高い密封（シール）性を発揮する。
【００２１】
また、図１と図２に示すように、軸８の段付面１０に対応（対面）するシール本体４の底壁部１９の肉厚寸法Ｔを、シール本体４の軸心方向寸法Ｈの３５％〜５０％と十分に（他の部分よりも）厚く設定する。即ち、次式のように設定する。
０．３５　×Ｈ≦Ｔ≦０．５０×Ｈ　　　▲４▼
上記式▲４▼に於て、下限値未満であると急激に気体（高圧水素ガス）の透過量が増大する。逆に、上限値を越すと、シールとしての不必要な部分が増加し、材料の無駄が生ずる。
【００２２】
図１〜３の実施の形態に於て、シール抜け止め用小凸条１３の外径寸法Ｄ_１３は前記▲２▼式（又は▲３▼式）のように、十分小さく設定されているので、シール本体４の内リップ部１は、軽く弾性変形しつつ容易に、収納凹所９内へ装着でき、収納凹所９内で内リップ部１───特にシール用突起１６と係止用突起１７───は弾性復元力が損なわれることなく、従って、十分なシール用接触面圧が得られて、優れたシール性能を発揮できる。
このとき、緩やかなテーパ面（傾斜面）１３ａによって、一層、軽くかつ容易に、シールＳが小凸条１３を越えることが可能となる。かつ、係止面１３ｂは、軸心１５に直交する略平面状であるので、一旦装着されたシールＳはその係止用突起１７が確実に係止して、シールＳが収納凹所９から抜け出ない（飛び出さない）という利点がある。
【００２３】
そして、前記▲２▼式に於て、外径寸法Ｄ_１３が下限値未満であると、多数のシールＳの内で、使用条件によって、小凸条１３を乗り越えて、収納凹所９から抜け出るものが、急に増加する。逆に、上限値を越すと、シール装着時に小凸条１３によって、内リップ部１のシール用突起１６が損傷を受け、あるいは、上述の樹脂材質ではシール用突起１６が拡径方向に塑性変形してしまって、高圧水素ガスの漏洩量が、急激に増加する。
【００２４】
次に、図４、図５、図６、図７は各々他の実施の形態を示す。
図４と図５に於て、（図２と比較すれば明らかなように、）内リップ部１のシール用突起２６が、外リップ部２のシール用突起２３と同様の低三角山型とした場合であって、かつ、軸８のシール抜け止め用小凸条１３の外径寸法Ｄ_１３が、軸８の外径寸法_１２に対して、比較的大きい場合を示す。
【００２５】
図６に於て、内リップ部１のシール用突起２７を、シール本体４の内リップ部１の先端面と一致した位置とし、従って、シール抜け止め用小凸条１３に、この突起２７が係止して、抜け止めの役目も兼ねる構造である。
【００２６】
図７に於て、内リップ部１のシール用突起（接触部）２８を、軸心方向に小さな幅のある面状とし、バネ５の開口端部２５の弾発付勢力が、シール用突起（接触部）２８に伝わり易くした構成である。即ち、図６ではバネ５の開口端部２５の軸心方向位置と、シール用突起２７の位置とが、僅かにずれていたのを、図７では、面状のシール用突起（接触部）２８の少なくとも一部を、バネ５の開口端部２５の軸心方向位置と一致させて、バネ５の弾発付勢力を、有効に軸との接触面圧増加に、活用している。
【００２７】
図８は、既述の図１〜図３の実施の形態を、図４〜図７と比較のために改めて図示したものであり、図７の面状に接触するシール用突起２８を、線状に近く、接触する三角形状のシール用突起１６とすると共に、図６に示したシール兼係止用の突起２７を、別途、先端側の突起１７として、付設した構成である。
この図４〜８は、以下に述べる実施例及びその漏れ試験の実測結果に対応する。
【００２８】
【実施例】
実施例１，２，３，４，５は夫々図４，図５，図６，図７，図８に対応し、バネ５を装着前の自由状態のシールＳの径方向寸法（厚さ寸法）Ｗは全て　１．７ｍｍ、軸心方向寸法Ｈは全て　２．７ｍｍ、底壁部１９の肉厚寸法Ｔを　１．０ｍｍ、底壁部１９の内径ｄ_１　、外径ｄ_２　を夫々　３．１ｍｍ、　５．９ｍｍとし、シール本体４の材質を前述の変性ＰＴＦＥ、バネ５の材質をインコネル（登録商標）を用いた。
【００２９】
他方、軸８の小径部１２の（基本）外径寸法Ｄ_１２は全て　３．０ｍｍとし、シール抜け止め用小凸条１３の外径寸法Ｄ_１３は、図４では　３．８ｍｍ（１．２７×Ｄ_１２）、図５では　３．６ｍｍ（１．２０×Ｄ_１２）、図６〜図８では　３．２ｍｍ（１．０７×Ｄ_１２）とする。また、ハウジング孔部７の内径寸法は、全て　６．０ｍｍとした。
漏れ試験用流体として、２０ｋｇｆ／ｃｍ^２　の窒素ガスを用いて、漏れ量を測定した結果を、次の表１に示す。
【００３０】
【表１】

【００３１】
上記表１から次のことが分かる。
シール抜け止め用小凸条１３の外径寸法Ｄ_１３の軸外径寸法Ｄ_１２に対する比が、　１２５％を越すと急激に漏れ量Ｑが増加する（実施例１）。その理由は、装着時にシール本体４の内リップ部１が大きく拡径した状態で小凸条１３を乗り越えるため、シール用突起２６が装着後も拡径状態となって十分な軸との接触面圧が得られないためと考えられる。
【００３２】
そこで、図５（実施例２）のように、（Ｄ_１３／Ｄ_１２）の百分率を　１２０％とすれば、漏れ量が約１／１０に急に改善されることが分かる。
さらに、図６（実施例３）のように、（Ｄ_１３／Ｄ_１２）の百分率を　１０７％と低減し、シール装着時の拡径（引き伸ばし）の度合を低く抑えると共に、シール用突起２７を（図６のように）先端面１８に形成すると、　４．８ｍＬ／ｍｉｎ　に減少している。
【００３３】
図７（実施例４）のように、（Ｄ_１３／Ｄ_１２）の百分率をそのままで、シール用突起２８を帯状（面状）に軸８に接触するようにし、バネ５の弾発力がその接触する部位に伝わり易くすると、　１．４ｍＬ／ｍｉｎ　まで漏れは減少する。
次に、図８（実施例５）の如く、軸８に対して、線接触状に接触するようなシール用突起１６を変更し、かつ、先端に係止用突起１７を付加すると、漏れは　０．３ｍＬ／ｍｉｎ　と、著しく減少していることが分かる。
【００３４】
なお、（Ｄ_１３／Ｄ_１２）の百分率を　１０７％未満とした試作品でも漏れ試験を行ったところ、シールが収納凹所９から抜け出る（飛び出す）ことが発生する。このようにシールが収納凹所９から抜け出ない（（Ｄ_１３／Ｄ_１２）の下限値が、　１０７％である。
【００３５】
【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によれば、）小凸条１３を軸８の外周面８ａに一体形成するので、構造が簡素で、高圧水素ガス密封構造の容積が増加せず、コンパクトである。即ち、軸８の端部又はハウジング孔部７に抜け止め部材をネジ等で取付ける必要がない。そして、シールＳの収納凹所９への装着作業も容易かつ迅速に行い得る。
従って、水素ガス燃料電池車のレギュレータ電磁弁等の弁類に好適な密封構造であるといえる。
【００３６】
（請求項２によれば、）シールＳを収納凹所９へ装着する際、シール本体４（の内リップ部１）の引き伸ばしを抑えることができて、使用状態で流体漏れを微量に抑えることができる。しかも、装着後（使用状態）において、圧力変動あるいは軸８と孔部７の相対的動きに伴って、シールＳが収納凹所９から抜け出ることも、防止できる。
【００３７】
（請求項３によれば、）内リップ部１が軸８に直接的に接触する部分が、シール用突起１６と係止用突起１７の２重の構造であるので、シール（密封）性が極めて高い。
また、軸８の一部に係止する係止用突起１７によって、確実にシールＳの抜け出ることを防止でき、シール用突起１６の軸心方向位置をバネ５の作用点に一致させて配設することも容易となるので、シール用突起１６の軸８への接触面圧も十分に高め得て、優れたシール（密封）性を発揮できる。
【００３８】
（請求項４によれば、）被密封流体としての水素ガスの圧力が、例えば、５０ＭＰａと高くても、底壁部１９を通してのガス透過を十分低く抑えることができる。しかも、不必要にシール本体４が大きくなることも防いでいる。
（請求項５によれば、）バネ５の弾発付勢力が有効にシール用突起１６，　２３に伝達される。これによって、軸８の外周面、ハウジング孔部７の内周面に対する、接触面圧を十分に高めて、確実にシール性能を発揮する。
（請求項６によれば）充填材入りＰＴＦＥに比べて、漏れ量が一層減少する。しかも、変性ＰＴＦＥと、Ｎｉ−Ｃｒ系の耐食合金の結合により、例えば５０ＭＰａもの高圧の水素ガスに適用可能となり、漏れが極力少なく、耐クリープ性にも優れ、十分な耐食性が得られる。
【図面の簡単な説明】
【図１】本発明に係る密封構造の実施の一形態を示し構成材の位置関係及び寸法関係を説明する図である。
【図２】シールの断面図である。
【図３】シールが装着される箇所の説明断面図である。
【図４】他の実施の形態を示す説明図である。
【図５】別の実施の形態を示す説明図である。
【図６】さらに他の実施の形態を示す説明図である。
【図７】さらに別の実施の形態を示す説明図である。
【図８】上記実施の一形態を他と比較のために示す説明図である。
【図９】従来例を示す断面説明図である。
【符号の説明】
１　内リップ部
２　外リップ部
４　シール本体
５　バネ
６　ハウジング（ボディ）
７　孔部
８　軸
８ａ　外周面
９　収納凹所
１０　　段付面
１３　　シール抜け止め用小凸条
１６　シール用突起
１７　　係止用突起
１９　　底壁部
２３　　シール用突起
Ｓ　シール
Ｔ　肉厚寸法
Ｄ_０　，Ｄ_１２，Ｄ_１３　外径寸法
Ｈ_０　，Ｈ_１　　軸心方向寸法[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-pressure hydrogen gas sealing structure and a seal therefor.
[0002]
[Prior art]
Recently, research and development of hydrogen gas fuel cell vehicles have been progressing, but valves such as regulator solenoid valves are used in the piping for sending high-pressure hydrogen gas as fuel. Heretofore, no suitable sealing seal has been available.
[0003]
[Problems to be solved by the invention]
As shown in FIG. 9, a rubber O-ring 41 is used as a seal for general fluid valves, and a concave peripheral groove 43 formed integrally with a spool (shaft) 42. In FIG. 5, the O-ring 41 was attached beyond the basic diameter end 44 while elastically expanding the diameter of the O-ring 41 as indicated by the two-dot chain line. Reference numeral 45 denotes a valve body (also called a housing or a body), and the O-ring 41 comes into contact (sliding contact) with the inner peripheral surface of the hole 45a.
[0004]
The reason for using the above-mentioned integral groove is that, in the case of the divided groove structure, the basic diameter end portion shown in FIG. 9 is fastened with a screw, a bolt, a snap ring, or the like as a separate component, so that the space becomes large. This is because there is a problem such as an increase in the volume of the kind.
However, when the fluid to be sealed is the hydrogen gas fuel cell vehicle, the pressure becomes high, for example, 50 MPa, and the pressure fluctuates at the time of ON-OFF operation of the valves, so that the above rubber O-ring 41 generates blisters. There was a fear.
Further, the O-ring made of metal cannot be mounted in the integrated groove structure because the diameter cannot be expanded (stretched) as shown by the two-dot chain line in FIG. In addition, since the spool (shaft) 42 reciprocates in the axial direction (small dimension), the wear of the hole 45a and the wear of the metal O-ring are remarkable, which is not suitable for use.
Accordingly, an object of the present invention is to provide a hermetically sealed structure that is applicable to valves such as a regulator solenoid valve for controlling the pressure of high-pressure hydrogen gas of automotive fuel as described above, and has a simple and compact structure. To provide. It is another object of the present invention to provide a seal and a sealing structure in which the conventional blister is not generated, the external leakage of high-pressure hydrogen gas is small, and the service life is long.
[0005]
[Means for Solving the Problems]
The high-pressure hydrogen gas sealing structure of the present invention includes a resin seal body in which an opening groove is formed in one axial direction by an inner lip portion and an outer lip portion, and a seal provided in a spring provided in the opening groove. In a sealed structure mounted in a storage recess formed between a housing hole and a shaft, the shaft has a stepped surface that forms the inner bottom surface of the storage recess, and the seal has a shaft. At a position apart from the stepped surface by a dimension larger than the central dimension, a small ridge for preventing the seal from coming off is formed integrally with the outer peripheral surface of the shaft.
[0006]
It is preferable that the outer diameter of the small convex strip for preventing the seal from coming off is set to 104% to 125% of the outer diameter of the portion where the shaft forms the inner peripheral surface of the storage recess.
In the seal for high-pressure hydrogen gas of the present invention, the inner lip portion has a seal protrusion and a locking protrusion that can be locked to a part (small ridge) of the shaft. It is preferable that the thickness of the bottom wall on the back side of the opening groove of the seal body is set to 35% to 50% of the axial dimension of the seal body.
[0007]
Further, the axially acting position of the spring that resiliently urges the opening groove in the opening direction and the axially located position of the top of the sealing projection of the inner lip and the sealing projection of the outer lip coincide with each other. Let it.
The material of the seal body is preferably modified PTFE, and the material of the spring is preferably a Ni-Cr-based corrosion-resistant alloy.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
1 to 3 show an embodiment of the present invention, FIG. 2 is a cross-sectional view of a seal S in a free state, FIG. 3 is a cross-sectional view illustrating a mounting (use) location, and FIG. It is a figure explaining the positional relationship and dimensional relationship between this seal | sticker S and a mounting (use) location.
The seal S has an inner lip portion 1 and an outer lip portion 2, and a resin seal body 4 having a substantially U-shaped cross section in which an opening groove portion 3 is formed in one axial direction by the inner and

outer lip portions

1, 2. And a spring 5 having a substantially U-shaped cross section provided in the opening groove portion 3.
[0009]
Between a hole 7 in a housing (body) 6 of a regulator solenoid valve for controlling high-pressure hydrogen gas and other valves such as a switching valve and a flow control valve, and a shaft 8 such as a spool or a valve rod (valve body). The seal S is mounted in the storage recess 9 formed in the above.
The shaft 8 has a stepped surface 10 which forms the inner bottom surface on the low pressure side of the storage recess 9, and a large diameter portion (land portion) 11 having an outer diameter dimension D ₀ slightly smaller than the hole portion 7. The small diameter portion 12 with which the inner lip portion 1 slides (contacts) is defined by the stepped surface 10.
[0010]
Only axial dimension H ₀ slightly larger than the axial dimension H of the seal S, in a position away from the stepped surface 10, a stop for the small ridges 13 missing seal, the outer circumferential surface 8a of the shaft 8, together Formed. Specifically, the small ridge 13 has a substantially trapezoidal triangular shape integrally formed in a protruding manner on the outer peripheral surface of the small-diameter portion 12, and the distal end surface 14 side of the small-diameter portion 12 has a gentle taper surface ( The stepped surface 10a is a locking surface 13b in a direction substantially perpendicular to the axis 15 of the shaft 8 or a steeply inclined surface or a small radius.
[0011]
The axis direction dimension H ₀ from the locking surface 13b, is intended to refer to a distance dimension to stepped surface 10. Then, as the following equation ▲ 1 ▼ is satisfied, it sets the axial dimension H _0.
1.10 × H ≦ H ₀ ≦ 1.25 × H (1)
In other words, the seal S is loose and has room for the movement of the shaft 8 in the axial direction.
[0012]
Then, the outer diameter _{D 13} of the sealing stopper for a small ridge 13 is set to 104% to 125% of the outer diameter _{D 12} of the portions where the shaft 8 forming the inner peripheral surface of the housing concavity 9. In particular, 105% to 110% is desirable.
This can be expressed by the following equations (2) and (3).
1.04 × D ₁₂ ≦ D ₁₃ ≦ 1.25 × D _{12 (} 2)
Preferably,
1.05 × D ₁₂ ≦ D ₁₃ ≦ 1.10 × D _{12 (} 3)
Note that the portion where the shaft 8 forms the inner peripheral surface of the storage recess 9 specifically corresponds to the small-diameter portion 12.
[0013]
By the way, the seal S will be described in detail. As a material of the seal body 4, modified PTFE is preferable, and as a material of the spring 5, a Ni—Cr-based corrosion-resistant alloy is preferable.
[0014]
In the present invention, the modified PTFE means a co-weight of tetrafluoroethylene and perfluoro (alkyl vinyl ether). An example of such a modified PTFE, at least one and a copolymer of tetrafluoroethylene of the general formula R-O-CF = perfluoro represented by CF ₂ (alkyl vinyl ether) is used. As the perfluoro (alkyl vinyl ether), those in which R in the above formula is a perfluoroalkyl group having 3 to 4 carbon atoms, such as perfluoro (propyl vinyl ether) and perfluoro (butyl vinyl ether), are preferred. Further, it is preferable to contain 0.1 to 10% by weight, preferably 0.5 to 5% by weight of perfluoro (alkyl vinyl ether).
[0015]
And, a material that does not mix the filler is desirable. The reason is that when the pressure of a high-pressure hydrogen gas such as 50 MPa acts, in the PTFE containing filler, the surfaces of the inner and

outer lip portions

1 and 2 become rough (fine irregularities occur), and the outer peripheral surface of the shaft 8 and the hole 7 The high-pressure hydrogen gas leaks easily from a portion (contact surface) that comes into contact with the inner peripheral surface of the substrate.
[0016]
As a Ni-Cr-based corrosion-resistant alloy applied to the spring 5, a corrosion-resistant alloy Inconel (registered trademark) of Ni 76%, Cr 16%, and Fe 8% is excellent in terms of corrosion resistance to hydrogen gas.
[0017]
The inner lip 1 has a sealing projection 16 and a locking projection 17 that can be locked to the locking surface 13 b of the small ridge 13 of the small diameter portion 12 of the shaft 8.
The locking projection 17 has a surface perpendicular to the axis formed as a continuous flat surface with the distal end surface 18 of the inner lip portion 1, and a gradient surface gradually increasing in diameter toward the thick bottom wall portion 19 of the seal body 4. 20.
[0018]
The sealing projection 16 has a triangular chevron shape having an axial center orthogonal surface 21 and a slope surface 22 whose diameter gradually increases toward the bottom wall 19. The two

projections

16 and 17 have the same inner diameter, and the projection 17 near the tip surface 18 is loosely mounted in the housing recess 9 with a margin in the axial direction as shown in FIG. Thus, when the seal body 4 is about to come off, the seal body 4 is locked on the locking surface 13b of the small ridge 13 for preventing the seal from coming off of the shaft 8 (small-diameter portion 12), and is reliably prevented from falling off. In addition, the locking projections 17 also perform a sealing function similarly to the adjacent sealing projections 16. In other words, the seal body 4 has a double seal lip (seal protrusion) on the inner peripheral surface side.
[0019]
On the other hand, the outer lip portion 2 has a low triangular sealing projection 23 having a gentle slope from the apex toward the distal end and the proximal end. As can be seen from FIG. 2, the sealing projections 23 on the outer lip portion 2 side and the sealing projections 16 on the inner lip portion 1 side are arranged on the same plane orthogonal to the axis 15. The axially acting position of the spring 5 that resiliently urges the opening in the opening direction and the axial position of the tops (apex) of the sealing

projections

16 and 23 are matched.
[0020]
The spring 5 has a U-shaped cross section, and is incorporated into the opening groove 3 of the seal body 4 so as to be open toward the distal end {toward the high-pressure hydrogen gas storage chamber 24}. The axial position at which the open ends 25, 25 having a U-shaped cross section come into contact with the inner and

outer lip portions

1, 2 and resiliently press them is the axial direction operating position. The operating position of the spring 5 (open ends 25, 25) and the tops (apex) of the inner and

outer seal projections

16, 23 are arranged on one orthogonal plane.
As a result, the elastic urging force of the spring 5 directly and effectively applies the contact surface pressure of the sealing

projections

16 and 23 to the mating member {the outer peripheral surface of the shaft 8 and the inner peripheral surface of the hole 7}. It can contribute to the increase and exhibit high sealing performance.
[0021]
As shown in FIGS. 1 and 2, the thickness T of the bottom wall portion 19 of the seal body 4 corresponding to (facing) the stepped surface 10 of the shaft 8 is determined by the dimension H of the seal body 4 in the axial direction. It is set to be sufficiently thick (35% to 50%) (compared to other portions). That is, it is set as in the following equation.
0.35 × H ≦ T ≦ 0.50 × H 4)
In the above formula (4), if it is less than the lower limit value, the permeation amount of gas (high-pressure hydrogen gas) sharply increases. Conversely, when the value exceeds the upper limit, unnecessary portions as a seal increase, and material is wasted.
[0022]
At a preferred embodiment of FIGS. 1-3, the seal exits the outer diameter D ₁₃ of the stopper for the small ridges 13 the ▲ 2 ▼ as in formula (or ▲ 3 ▼ formula), since it is set sufficiently small The inner lip portion 1 of the seal body 4 can be easily mounted in the storage recess 9 while being lightly elastically deformed, and the inner lip portion 1. The projection 17 # does not impair the elastic restoring force, so that a sufficient sealing contact surface pressure can be obtained and excellent sealing performance can be exhibited.
At this time, the gentle taper surface (inclined surface) 13a allows the seal S to lightly and easily pass over the small ridge 13. In addition, since the locking surface 13b has a substantially planar shape perpendicular to the axis 15, the locking projections 17 of the mounted seal S are securely locked, and the seal S is removed from the storage recess 9. There is an advantage that it does not escape (do not jump out).
[0023]
Then, the ▲ 2 ▼ At a formula, when the outer diameter D ₁₃ is less than the lower limit value, among the plurality of seal S, depending on usage conditions, overcoming small ridge 13, exits the housing concavity 9 Things increase rapidly. Conversely, if the upper limit is exceeded, the sealing projection 16 of the inner lip portion 1 is damaged by the small ridge 13 when the seal is attached, or the sealing projection 16 is plastically deformed in the radially expanding direction with the above-mentioned resin material. As a result, the leakage amount of the high-pressure hydrogen gas sharply increases.
[0024]
Next, FIGS. 4, 5, 6, and 7 show other embodiments.
In FIGS. 4 and 5, the sealing projection 26 of the inner lip portion 1 has a low triangular mountain shape similar to the sealing projection 23 of the outer lip portion 2 (as apparent from comparison with FIG. 2). a case has been, and outer diameter D ₁₃ of the stopper for the small ridges 13 missing seal shaft 8, the outer diameter ₁₂ of the shaft 8, a case relatively large.
[0025]
In FIG. 6, the sealing projection 27 of the inner lip 1 is located at a position corresponding to the tip end surface of the inner lip 1 of the seal body 4. It is a structure that locks and also serves as a stopper.
[0026]
In FIG. 7, the sealing projection (contact portion) 28 of the inner lip portion 1 is formed in a planar shape having a small width in the axial direction, and the resilient urging force of the open end 25 of the spring 5 is applied to the sealing projection. (Contact portion) 28. That is, in FIG. 6, the axial position of the opening end 25 of the spring 5 and the position of the sealing projection 27 are slightly deviated from each other. In FIG. 7, the planar sealing projection (contact portion) is different. At least a portion of the spring 28 is aligned with the axial position of the open end 25 of the spring 5, and the elastic biasing force of the spring 5 is effectively used to increase the contact surface pressure with the shaft.
[0027]
FIG. 8 shows the embodiment of FIG. 1 to FIG. 3 described above again for comparison with FIG. 4 to FIG. 7, and the sealing projection 28 that comes into contact with the surface of FIG. In this configuration, a triangular sealing projection 16 which is in contact with and close to the shape is provided, and a projection 27 for sealing and locking shown in FIG. 6 is separately provided as a projection 17 on the distal end side.
4 to 8 correspond to the examples described below and the actual measurement results of the leak test.
[0028]
【Example】

Embodiments

1, 2, 3, 4, and 5 correspond to FIGS. 4, 5, 6, 7, and 8, respectively, and show the radial dimension (thickness dimension) of the seal S in a free state before the spring 5 is mounted. 2.) W is 1.7 mm, axial dimension H is 2.7 mm, thickness T of bottom wall 19 is 1.0 mm, and inner diameter d ₁ and outer diameter d ₂ of bottom wall 19 are 3. The seal body 4 was made of the above-mentioned modified PTFE, and the material of the spring 5 was made of Inconel (registered trademark).
[0029]
On the other hand, the (basic) all outside diameter _{D 12} is 3.0mm diameter portion 12 of the shaft 8, the outer diameter _{D 13} of the stopper for the small ridges 13 missing seal in FIG. 4 3.8 mm (1.27 × D ₁₂ ), 3.6 mm (1.20 × D ₁₂ ) in FIG. 5, and 3.2 mm (1.07 × D ₁₂ ) in FIGS. The inner diameter of the housing holes 7 was all 6.0 mm.
The results of measuring the amount of leakage using a nitrogen gas of 20 kgf / cm ² as the leakage test fluid are shown in Table 1 below.
[0030]
[Table 1]

[0031]
The following can be seen from Table 1 above.
Ratio axis diameter D ₁₂ of the outer diameter D ₁₃ of the sealing stopper for a small ridges 13, rapidly leak amount Q increases exceeds 125% (Example 1). The reason is that the inner lip portion 1 of the seal main body 4 gets over the small ridge 13 in a state where the diameter is largely expanded at the time of mounting, so that the sealing projection 26 is in a state of expanded diameter even after mounting and has a sufficient contact surface with the shaft. It is considered that pressure cannot be obtained.
[0032]
Thus, as shown in FIG. 5 (Example 2), when the percentage of (D ₁₃ / D ₁₂ ) is set to 120%, it can be seen that the leakage amount is sharply reduced to about 1/10.
Further, as shown in FIG. 6 (Example 3), the percentage of (D ₁₃ / D ₁₂ ) is reduced to 107%, the degree of diameter expansion (extension) at the time of mounting the seal is suppressed, and the seal projection 27 is formed. When formed on the distal end surface 18 (as in FIG. 6), it is reduced to 4.8 mL / min.
[0033]
As shown in FIG. 7 (Embodiment 4), the sealing projection 28 is made to contact the shaft 8 in a band shape (plane shape) while keeping the percentage of (D ₁₃ / D ₁₂ ) as it is, and the elastic force of the spring 5 is reduced. Leakage is reduced to 1.4 mL / min when it is more easily transmitted to the contact area.
Next, as shown in FIG. 8 (Embodiment 5), if the sealing projection 16 is changed so as to be in linear contact with the shaft 8 and the locking projection 17 is added to the tip, leakage will occur. It can be seen that the remarkable decrease was 0.3 mL / min.
[0034]
When a leak test is performed on a prototype in which the percentage of (D ₁₃ / D ₁₂ ) is less than 107%, the seal may come off (project) from the storage recess 9. Thus, the lower limit of (D ₁₃ / D ₁₂ ) that the seal does not come out of the storage recess 9 is 107%.
[0035]
【The invention's effect】
The present invention has the following significant effects by the above configuration.
Since the small ridge 13 is formed integrally with the outer peripheral surface 8a of the shaft 8, the structure is simple, and the volume of the high-pressure hydrogen gas sealing structure does not increase and the device is compact. That is, there is no need to attach a retaining member to the end of the shaft 8 or the housing hole 7 with a screw or the like. Then, the work of mounting the seal S in the storage recess 9 can be performed easily and quickly.
Therefore, it can be said that the sealing structure is suitable for valves such as a regulator solenoid valve of a hydrogen gas fuel cell vehicle.
[0036]
According to the second aspect, when the seal S is installed in the storage recess 9, the extension of the (the inner lip portion 1) of the seal body 4 can be suppressed, and the fluid leakage in the use state can be suppressed to a very small amount. Can be. In addition, the seal S can be prevented from falling out of the storage recess 9 due to pressure fluctuation or relative movement between the shaft 8 and the hole 7 after the mounting (in use).
[0037]
Since the portion where the inner lip portion 1 directly contacts the shaft 8 has a double structure of the sealing projection 16 and the locking projection 17 (according to claim 3), the sealing (sealing) property is improved. Extremely high.
In addition, the locking projection 17 that locks to a part of the shaft 8 can reliably prevent the seal S from coming off, and the position of the sealing projection 16 in the axial direction is aligned with the action point of the spring 5. Therefore, the contact surface pressure of the seal projection 16 with the shaft 8 can be sufficiently increased, and excellent sealing (sealing) can be exhibited.
[0038]
(According to claim 4) Even if the pressure of the hydrogen gas as the sealed fluid is as high as, for example, 50 MPa, gas permeation through the bottom wall portion 19 can be sufficiently suppressed. Moreover, it also prevents the seal body 4 from becoming unnecessarily large.
(According to claim 5), the elastic urging force of the spring 5 is effectively transmitted to the sealing

projections

16 and 23. Thereby, the contact surface pressure on the outer peripheral surface of the shaft 8 and the inner peripheral surface of the housing hole 7 is sufficiently increased, and the sealing performance is reliably exhibited.
The leakage amount is further reduced as compared to filled PTFE. In addition, the combination of the modified PTFE and the Ni-Cr-based corrosion-resistant alloy enables application to a high-pressure hydrogen gas of, for example, 50 MPa, and minimizes leakage, has excellent creep resistance, and provides sufficient corrosion resistance.
[Brief description of the drawings]
FIG. 1 is a view illustrating an embodiment of a sealing structure according to the present invention and illustrating a positional relationship and a dimensional relationship of components.
FIG. 2 is a sectional view of a seal.
FIG. 3 is an explanatory sectional view of a place where a seal is mounted.
FIG. 4 is an explanatory diagram showing another embodiment.
FIG. 5 is an explanatory diagram showing another embodiment.
FIG. 6 is an explanatory diagram showing still another embodiment.
FIG. 7 is an explanatory diagram showing still another embodiment.
FIG. 8 is an explanatory diagram showing one embodiment of the above for comparison with another.
FIG. 9 is an explanatory sectional view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner lip part 2 Outer lip part 4 Seal body 5 Spring 6 Housing (body)
7 Hole 8 Shaft 8a Outer peripheral surface 9 Storage recess 10 Stepped surface 13 Small ridge 16 for preventing seal coming off Sealing protrusion 17 Locking protrusion 19 Bottom wall 23 Sealing protrusion S Seal T Thickness D ₀ , D ₁₂ , D ₁₃ outer diameter dimension H ₀ , H ₁ axial dimension

Claims

A resin seal body (4) in which an opening groove (3) is formed in one axial direction by an inner lip (1) and an outer lip (2), and a spring (5) provided in the opening groove (3). ) And a seal (S) comprising a housing (7) and a housing (9) formed between the housing hole (7) and the housing (9). is stepped surface forming a bottom surface of the housing recess (9) (10) is formed, a large dimension (H ₀₎ than the axial direction dimension (H) of the seal (S) only with the stage A high-pressure hydrogen gas sealing structure, wherein a small convex strip (13) for preventing a seal from being detached is formed integrally with the outer peripheral surface (8a) of the shaft (8) at a position away from the surface (10).

The outer diameter of the sealing stopper for a small ridge (13) to (D _13), said axis (8) of the housing recess (9) the inner peripheral surface outside diameter of the portion to form a (D ₁₂₎ The high-pressure hydrogen gas sealing structure according to claim 1, wherein the pressure is set to 104% to 125% of the pressure.

A resin seal body (4) in which an opening groove (3) is formed in one axial direction by an inner lip (1) and an outer lip (2), and a spring (5) provided in the opening groove (3). ), The inner lip portion (1) has a sealing projection (16) and a locking projection (17) which can be locked to a part of the shaft (8). A high-pressure hydrogen gas seal comprising:

A resin seal body (4) in which an opening groove (3) is formed in one axial direction by an inner lip (1) and an outer lip (2), and a spring (5) provided in the opening groove (3). ), The thickness dimension (T) of the bottom wall surface (19) on the back side of the opening groove (3) of the seal body (4) is set to the thickness (T) of the seal body (4). A high-pressure hydrogen gas seal characterized in that it is set to 35% to 50% of the axial dimension (H) of (1).

A resin seal body (4) in which an opening groove (3) is formed in one axial direction by an inner lip (1) and an outer lip (2), and a spring (5) provided in the opening groove (3). ), The axially acting position of the spring (5) for resiliently urging the opening groove (3) in the opening direction, and the inner lip (1). A high-pressure hydrogen gas seal wherein the axial positions of the tops of the sealing projections (16) and the sealing projections (23) of the outer lip portion (2) are matched.

The high-pressure hydrogen gas seal according to claim 3, wherein the material of the seal body (S) is modified PTFE, and the material of the spring (5) is a Ni-Cr-based corrosion-resistant alloy.