技術分野
本発明は、側面衝突用、又は助手席用のエアバッグを膨張展開させるのに好適なガス発生器に関する。
背景技術
側面衝突用、又は助手席用のエアバッグを膨張展開させるガス発生器の一例としては、第７図に示すものがある。
第７図のガス発生器は、主として側面衝突用のエアバッグを膨張展開させるためのもので、一端が開口する長尺円筒状の外筒材５２、及び外筒材５２の開口側を閉鎖する蓋部材５３とで構成されるハウジング５１を備えている。このハウジング５１は、蓋部材５３を外筒材５２の内周段部５２ａまで嵌挿し、外筒材５２の開口端５２ｂを内側に折り曲げることで、蓋部材５３を外筒材５２内の開口側に位置決めする。また、蓋部材５３には、外筒材５２の内周回りで開口する環状溝５３ａが形成され、該環状溝５３ａ内にシールリング５４を装着してなる。このシールリング５４は、外筒材５２の開口端５２ｂを折り曲げるとき、外筒材５２の内周及び環状溝５３ａに弾接され、ハウジシグ５１の内部を密封する。
また、ハウジング５１の内部には、仕切リング板５５によって、ハウジング１の軸方向に燃焼室５６、及び冷却濾過室５７が形成されている。燃焼室５６内には、燃焼により高温ガスを発生するガス発生剤５８が装填され、又、冷却濾過室５７内には、ガス発生剤５８の燃焼により発生した高温ガスを濾過、冷却する円筒状のフィルター材５９が装着されている。さらに、外筒材５２の底部５２ｃには、燃焼室５２内に火炎を噴出する点火器６０が装着されている。
このガス発生器においては、衝突センサーからの衝突信号により点火器６０を通電発火し、この火炎を燃焼室５６内に噴出させて、ガス発生剤５８を着火燃焼させることで、多量の高温ガスを急速に発生させる。燃焼室５２内で発生した高温ガスは、仕切リング板５５内を通じて冷却濾過室５７内に流入した後、フィルター材５９内に流入し、ここで冷却とスラグ捕集を経て、ハウジング５１の各ガス放出孔５１ａからエアバッグ内に放出される。エアバッグは、各ガス放出孔５１ａから放出される多量の清浄なガスによって、急速に膨張展開される。
ところで、近年、ガス発生器の技術分野では、小型・軽量化の他に、低価格のガス発生器が要求されつつある。
この観点からして、従来のガス発生器では、蓋部材５３を外筒材５２の開口側に位置決めするため、外筒材５２に内周段部５２ａを別途加工する必要があり、製造コストを低減することが困難である。
また、内周段部５２ａを加工することは、この部分において外筒材５２の厚さが薄くなり、強度的に弱い構造となる。したがって、ガス発生剤５８の燃焼により、ハウジング５１内に発生する高温、高圧ガスに耐え得る構造とするには、外筒材５２全体の厚みを内周段部５２ａだけ厚くする必要がある。
この結果、従来のガス発生器では、内周段部５２ａを加工することにより、製造コストが高くなり、また、外筒材５２全体の厚みを内周段部５２ａだけ厚くすることにより、小型・軽量化を達成することが困難なものとなる。
本発明の目的は、小型・軽量化を図りつつ、低価格のガス発生器を提供することにある。
発明の開示
本発明のガス発生器（請求の範囲第１項）は、少なくとも一端が開口する長尺円筒状の外筒材と、外筒材内に嵌挿され、該外筒材の開口側を閉鎖する蓋部材とでハウジングを構成する。外筒材内には、燃焼により高温ガスを発生するガス発生剤を装填し、高温ガスの冷却及びスラグ捕集を行うフィルター材を配置する。ハウジングには、外筒材内のガス発生剤を着火燃焼させる１又は複数の点火手段を装着してなる。また、本発明のガス発生器では、外筒材の内周回りで開口する環状溝を蓋部材に形成し、該環状溝内に弾性リングを装着してなる。そして、外筒材の開口側を環状溝内に突出して環状突起を形成し、該環状突起は、弾性リングを環状溝に弾接しつつ該環状溝の形状に倣って嵌め込まれる構造とする。
これによって、環状突起は、弾性リングを蓋部材の環状溝に弾接して、該外筒材内を外部から密封閉鎖する。また、環状突起は、弾性リングを環状溝に弾接すると同時に、環状溝の形状に倣って嵌め込まれ、環状溝に対して内側から当接する。これで、蓋部材は、環状溝と環状突起との当接により、外筒材内での移動が規制され、該外筒材の開口側にて位置決めされる。
このことから、本発明のガス発生器では、環状突起と環状溝との協働によって、外筒材内を外部から密封閉鎖すると同時に、蓋部材を外筒材の開口側に位置決めするものである。
したがって、蓋部材を外筒材の開口側に位置決めするため、外筒材の内周に段部を加工し、該段部の加工に伴って外筒材を厚くする必要もない。
しかも、環状突起の突出量、環状溝の形状、及び外筒材の厚さを適宜選択することで、外筒材の密封閉鎖と、蓋部材の位置決めとを確実に行えるとともに、ガス発生剤の燃焼で発生する高温、高圧ガスによって、蓋部材が外筒材から抜け出ることも防げる。
本発明となるガス発生器（請求の範囲第２項）では、請求の範囲第１項のものに、環状突起を、外筒材の外周回りに施される絞り加工によって、環状溝内に突出形成するものである。
これによって、外筒材の外周回りに絞り加工を施すという、簡単な加工によって、外筒材内の密封閉鎖と、蓋部材の位置決めを行える。
本発明となるガス発生器（請求の範囲第３項）では、請求の範囲第１項又は請求の範囲第２項のものに、環状溝を、外筒材の内周回りで開口するＶ字形状としたものである。
これによって、環状突起を形成するとき、蓋部材に過剰な負荷を加えることなく、環状突起を環状溝のＶ字形状に倣わすことができる。
本発明となるガス発生器（請求の範囲第４項）では、請求の範囲第３項のものに、環状溝の傾斜角度θをθ＝４０〜５０°となし、外筒材の厚さｄと環状溝の深さｈとの比率ｈ／ｄを２以下とするとともに、環状突起の突出量ｆをｆ＝０．７０〜１．００×ｄとしたものである。
これによって、外筒材内の密封閉鎖と、蓋部材の外筒材の開口側への位置決めとを確実に行えると同時に、ガス発生剤の燃焼による高温、高圧ガスによって蓋部材が外筒材内から抜け出ることもより確実に防げる。
本発明となるガス発生器（請求の範囲第５項）では、請求の範囲第１項のものに、蓋部材に、環状突起を突出形成するとき、外筒材の開口端側に係合するフランジを形成してなるものである。
これによって、蓋部材のフランジと外筒材の開口端側との係合により、外筒材の開口端側が拡径する等の変形を起こすことを規制して、環状突起を確実に環状溝の形状に倣わせることができる。
発明を実施するための最良の形態
本発明の実施形態におけるガス発生器について、第１図〜第６図を参照して説明する。
第１図及び第２図のガス発生器Ｓは、主として側面衝突用のエアバッグを膨張展開させるもので、両端が開口する長尺円筒状の外筒材２と、外筒材２の各開口側５，６を閉鎖する蓋部材３，４とを備え、これら部材２〜４でハウジング１を構成する。このガス発生器Ｓは、外筒材２の各開口側５，６を密封閉鎖し、各蓋部材３，４を外筒材２の各開口側５，６に位置決め等を行うカシメ手段７，８を備えている。また、ガス発生器Ｓは、円筒状のフィルター材９、ガス発生剤１３及び点火手段３４とを備えてなる。
ハウジング１は、各蓋部材３，４を外筒材２の各開口側５，６内に嵌挿することで構成され、各カシメ手段７，８によって内部に密封空間Ｐ１を形成する構造である。外筒材２には、密封空間Ｐ１とエアバッグとを連通する複数のガス放出孔２ａが形成されている。各ガス放出孔２ａは、外筒材２の軸方向のフィルタ材９が配置された部位に開口して、該外筒材２の周方向及び軸方向に所定間隔ごとに形成されている。また、各ガス放出孔２ａは、外筒材２の内周に貼着されるバーストプレート１４によって閉鎖されている。バーストプレート１４は、アルミ等の金属箔によって形成され、ハウジング１内の防湿と内圧調整の役割を果たす。蓋部材３，４には、外筒材２内の各開口側５，６に嵌挿する段差１９が形成されている。この段差１９は、外筒材２の厚さｄと等しい深さを有している。また、蓋部材３，４には、外筒材２の径方向に突出するフランジ１５が形成され、該各フランジ１５の内側１５ａは外筒材２の各開口端側２ｂに係合している。なお、外筒材２、各蓋部材３，４は、耐熱、耐圧性に優れたステンレス等の鋼材にて製作する。
各カシメ手段７，８は、外筒材２の各開口側５，６に夫々設けられている。
このカシメ手段７は、第３図にも示す如く、環状溝１６、弾性リング１７及び環状突起１８とで構成される。
環状溝１６は、蓋部材３に形成され、フランジ１５に連続して外筒材２の開口側５の内周回りで開口している。この環状溝１６は、外筒材２の内周に開口するＶ字形状に形成されている。また、環状溝１６のＶ字形状は、所定の傾斜角度θ、幅ｔ及び深さｈをもって、外筒材２の内周に向けて拡がるテーパー形状１６ａ，１６ｂを有してなる〔第３図（ａ）参照〕。
弾性リング１７は、環状溝１６内に装着され、外筒材２の開口側５の内周に当接している。この弾性リング１７としては、ウレタンゴム、ニトリルゴム、フッ素ゴム、エチレンプロピレンゴム等の弾性材を環状に成形したＯリングを用いるのが好ましい。
環状突起１８は、外筒材２の外周回りに絞り加工を施すことで、外筒材２の開口側５を環状溝１６内に突出して形成される。この絞り加工は、外筒材２の開口側５の内径を減少変形しつつ、該開口側５を環状溝１６内に突出させるものである。また、環状突起１８は、絞り加工によって、弾性リング１７を環状溝１６の各テーパー形状１６ａ，１６ｂに弾接し、該テーパー形状１６ａ，１６ｂに倣って嵌め込まれる。このとき、環状溝１６をＶ字状に形成しているので、絞り加工による過剰な負荷を蓋部材３に加えることなく、環状突起１８をスムーズに環状溝１６の各テーパー形状１６ａ，１６ｂに倣わすことができる。また、外筒材２の開口側５に絞り加工を施すと、外筒材２の開口端側２ｂは、環状溝１６のテーパー形状１６ａから連続して、蓋部材３の内側１５ａに倣って変形される。これで、蓋部材３のフランジ１５は、外筒材２の開口端側２ｂとの係合によって、該開口端側２ｂが拡径する等の変形を起こすことを規制して、環状突起１８を確実に環状溝１６の各テーパー形状１６ａ，１６ｂに倣わせしめる〔第３図（ｃ）参照〕。
この環状突起１８は、環状溝１６内への嵌め込みで、環状溝１６の内側から各テーパー形状１６ａ，１６ｂに当接され、蓋部材３を移動不能として外筒材２の開口側５に位置決めする。また、環状突起１８は、弾性リング１７を環状溝１６に弾接することで、外筒材２の開口側５と蓋部材３との間を密封閉鎖する。なお、環状突起１８の突出量ｆは、環状溝１６の傾斜角度θと、外筒材２の厚さｄと環状溝１６の深さｈの比率等との関係で決定されるもので、外筒材２の開口側５の密封閉鎖と、蓋部材３の位置決めを確実にでき、しかも、ハウジング１内で発生する高温、高圧ガスによって、蓋部材３が外筒材２内から抜け出ない強度とする。この外筒材２の厚さｄは、絞り加工により環状突起１８を形成でき、ハウジング１内で発生する高温、高圧ガスに耐えるものとする。
そして、環状溝１６の傾斜角度θ、環状溝１６の深さｈと外筒材２の厚さｄとの比率ｈ／ｄ及び環状突起１８の突出量ｆは、密封閉鎖、位置決めすることがででき、しかも抜け止めできるものにされる。
（１）環状溝１６の傾斜角度θは、θ＝４０〜５０°の範囲内とするのが好ましい。
この傾斜角度θについては、傾斜角度を大きくすると、環状突起１８と環状溝１６との係止力が十分に得ることができず、逆に傾斜角度を小さくすると、外筒材９の外周回りに絞り加工を施すとき、各蓋部材３，４等に過剰な負荷が作用し歪み等が発生する。このような観点から、係止力を十分に得ることができ、歪み等を生じさせない傾斜角度θとして、θ＝４０〜５０°としたものである。
なお、傾斜角度θにおいて、テーパー形状１６ａ側の傾斜角度θａとテーパー形状１６ｂ側の傾斜角度θｂとを同一にすることは必ずしも必要でない。但し、各蓋部材３，４が外筒材２内から抜け出すことを防ぐためには、特に、傾斜角度θｂ＝４０〜５０°とすることが好ましい。また、外筒材２への絞り加工時に、絞り加工による力が各蓋部材３，４へ均等に加わるように、傾斜角度θａとθｂとは略同一であることが好ましい。
（２）環状溝１６の深さｈと外筒材２の厚さｄとの比率は、ｈ／ｄ＝２以下とするのが好ましい。
また、比率ｈ／ｄを大きくしすぎると、環状溝１６の深さｈが深くなり、各蓋部材３，４の強度が低下するので、２以下とすることが好ましい。この比率ｈ／ｄについては、環状突起１８と環状溝１６との係止力が得られれば、適宜選択することができるが、１以上とすることがより好ましい。
（３）環状突起１８の突出量ｆは、０．７０〜１．００×ｄとするのが好ましい。
突出量ｆについては、０．７０〜１．００×ｄの範囲以下であると、環状突起１８と環状溝１６との係止力が十分に得られない恐れがあり、該範囲以上であると、環状突起１８によるかしめ強度が低下する恐れがある。この観点から、係止力やカシメ強度を十分に得ることができる突出量ｆとして、ｆ＝０．７０〜１．００×ｄとしたものである。
これで、カシメ手段７は、環状溝１６と、該環状溝１６の各テーパー形状１６ａ，１６ｂに倣って嵌め込まれる環状突起１８との協働で、弾性リング１７を弾性変形して、外筒材２の開口側５と蓋部材３との間を密封閉鎖すると同時に、蓋部材３を外筒材２の開口側５に位置決めして、抜け止めする〔第３図（ｃ）参照〕。
カシメ手段８は、第４図にも示す如く、カシメ手段７と同様な、環状溝１６、弾性リング１７及び環状突起１８とで構成される。このカシメ手段８においても、環状溝１６と、該環状溝１６の各テーパー形状１６ａ，１６ｂに倣って嵌め込まれる環状突起１８との協働で、弾性リング１７を弾性変形して、外筒材２の開口側６と蓋部材４との間を密封閉鎖すると同時に、蓋部材４を外筒材２の開口側６に位置決めして、抜け止めする〔第４図（ｂ）参照〕。
また、各カシメ手段７，８は、外筒材２の各開口側５，６と各蓋部材３，４との間をそれぞれ密封閉鎖することで、ハウジング１の内部に密封空間Ｐ１を形成する。
ハウジング１内の密封空間Ｐ１には、フィルター材９が配置され、ガス発生剤１３が装填されている。また、ハウジング１の蓋部材４には、点火手段３４が装着されている。
フィルター材９は、外筒材２の中程部位に配置され、各蓋部材３，４との間で第１燃焼室１０、及び第２燃焼室１１とを形成する。フィルター材９には、ハウジング１の軸方向に貫通する第３燃焼室１２が形成され、該第３燃焼室１２を通して第１及び第２燃焼室１０，１１を連通している。このフィルター材９は、メリヤス編み金網、平織り金網やクリンプ織り金属線材等の集合体を、円筒状に成形することで安価に製作される。なお、フィルター材９は、金網を複数巻回することによっても製作できる。
また、フィルター材９は、フィルター支持体２１によって支持され、さらに外筒材２の外周回りに施される絞り加工にて位置決めされる。このフィルター支持体２１は、フィルター材９の外周に装入される内筒材２２と、内筒材２２の外周の両軸端側に嵌め込まれる仕切りキャップ２３，２４とでなる。内筒材２２には、複数のガス通過孔２２ａが形成されている。また、各仕切りキャップ２３，２４は、外筒材２の内周に嵌挿され、内筒材２２と外筒材２との間に環状のガス通過空間Ｐ２を形成している。これら各仕切りキャップ２３，２４には、第１及び第２燃焼室１０，１１と第３燃焼室１２とを連通する開口穴２３Ａ，２４Ａが形成されている。これで、フィルター支持体２１は、各キャップ２３，２４を外筒材２の内周に嵌挿することによって、フィルター材９がハウジング１の径方向へ移動することを規制する。また、フィルター支持体２１は、各キャップ２３，２４によってフィルター材２の各軸端を閉鎖することで、各燃焼室１０，１１内で発生した高温ガスを該各キャップ２３，２４の開口穴２３Ａ，２４Ａから第３燃焼室１２内に導き、高温ガスが、直接、フィルター材９の各軸端、又はガス通過空間Ｐ２内に流出することを規制する。
そして、フィルター支持体２１は、絞り加工によって、外筒材２の内周に突出される各突起２５，２６に当接して、位置決めされる。各突起２５，２６は、フィルター材９の各軸端側から各キャップ２３，２４に当接し、フィルター支持体２１を挟む状態で支持する。これで、フィルター材９は、各突起２５，２６に当接するフィルター支持体２１によって、外筒材２の中程部位に位置決めされる。また、各突起２５，２６は、各キャップ２３，２４に隙間なく当接され、各燃焼室１０，１１で発生した高温ガスが各キャップ２３，２４と外筒材２の内周との間から直接、ガス通過空間Ｐ２内に流出するのを規制する〔第３図（ｃ）、及び第４図（ｂ）参照〕。
ガス発生剤１３は、燃焼により高温ガスを発生するもので、第１〜第３燃焼室１０〜１２にわたって装填されている。また、ガス発生剤１３は、クッション材３１，３２によって振動による粉状化が防止されている。クッション材３１は、第１燃焼室１０のガス発生剤１３と蓋部材４のクッション押え材３３との間に装着されている。このクッション材３１には、点火手段３４からの火炎の威力を遅延なく、確実にガス発生剤１３に伝達するための十字状の切欠きが形成されている。また、クッション材３２は、第２燃焼室１１のガス発生剤１３と蓋部材３２との間に装着されている。各クッション材３１，３２は、シリコンゴムやシリコン発泡体等の弾性材を用いて形成することが出来る。
点火手段３４は、通電発火する点火具のみで構成され、ハウジング１の内側から蓋部材４に装着される。また、点火手段３４は、第１燃焼室１０側に突出して、クッション押え材３３を通してクッション材３１に当接されている。この点火手段３４は、衝突センサーからの衝突検出信号に基づいて通電発火し、火炎を第１燃焼室１０内に噴出することで、第１燃焼室３内のガス発生剤１３を強制的に着火燃焼させる。
次に、ガス発生器Ｓの作動を説明する。
ガス発生器Ｓは、衝突センサーが自動車の衝突を検出すると、点火手段３４を通電発火させる。点火手段３４の火炎は、クッション材３１を破裂、開口した後、第１燃焼室１０内に噴出してガス発生剤１３を着火燃焼させることで、高温ガスを発生させる。
第１燃焼室１０内で発生した高温ガスは、仕切りキャップ２３によって、直接、ガス通過空間Ｐ２等に流れることなく、第３燃焼室１２内に導かれ、フィルター材９内に流入し、ここで冷却とスラグ捕集を経て、ガス通過空間Ｐ２内に流出される。このとき、第３燃焼室１２では、第１燃焼室１０から流れ込む高温ガスの熱等によって、ガス発生剤１３が着火燃焼され高温ガスを発生させる。また、第３燃焼室１２での燃焼は、第１燃焼室１０側から順次、ガス発生剤１３を燃焼させて、第２燃焼室１１側に移って行くことになる。
第１燃焼室１０での燃焼が進んで、ハウジング１内が所定圧力まで上昇すると、バーストプレート１４が破裂して、ガス通過空間Ｐ２内で均一にされた清浄なガスが各ガス放出孔２ａを通してエアバッグ１内に放出される。これで、エアバッグは、第１燃焼室４０等で発生した少量のガスにて緩やかに膨張展開を開始する。
また、ハウジング１内での圧力上昇に伴って、高温、高圧ガスは各蓋部材３，４に作用することになる。これら各蓋部材３，４は、高温、高圧ガスの作用によって、外筒材２内から抜け出ようとするが、環状溝１６のテーパー形状１６ｂが環状突起１８に当接することで、抜け止めされる〔第３図（ｃ）、及び第４図（ｂ）参照〕。
続いて、第１燃焼室１０、及び第３燃焼室１２での燃焼が進むと、第１燃焼室１０での燃焼開始から微小時間差をもって、第２燃焼室１１のガス発生剤１３が着火燃焼される。第２燃焼室１１での燃焼は、第３燃焼室１２から伝播、噴出される火炎、熱等によって行われ、ガス発生剤１３を着火燃焼させることで、高温ガスを発生させる。
第２燃焼室１１内で発生した高温ガスは、第３燃焼室１２内に導かれ、フィルター材９内に流入し、ここで冷却とスラグ捕集を経て、ガス通過空間Ｐ２内に流出する。このとき、ハウジング１内での燃焼は、各燃焼室１０〜１２における全体的な燃焼となり、ハウジング１内における圧力も最高圧力まで達する。
ガス通過空間Ｐ２内に流出した清浄なガスは、各ガス放出孔２ａからエアバッグ内に放出される。エアバッグは、各燃焼室１０〜１１内で発生する多量で最高圧に達した清浄なガスによって急速な膨張展開に移行される。
また、ハウジング１内が最高圧力まで達すると、高温、高圧ガスが各蓋部材３，４に作用することになるが、上述の如く、環状溝１６のテーパー形状１６ｂが環状突起１８に当接することで、各蓋部材３，４の抜け止めがなされる。
この結果、エアバッグは、展開初期におけて第１燃焼室１０、又は第１及び第３燃焼室１０，１２で発生した少量のガスにより緩やかに膨張展開を開始し、微小時間後から、各燃焼室１０〜１２で発生した多量で最高圧力のガスにより急速に膨張展開することになる。
このように、本発明のガス発生器Ｓでは、環状突起１８と環状溝１６との協働によって、外筒材２内を外部から密封閉鎖すると同時に、各蓋部材３，４を外筒材２の各開口側５，６に位置決めできる。したがって、各蓋部材３，４を、外筒材２の開口側５，６に位置決めするため、外筒材２の内周に段部を加工し、該段部の加工に伴って外筒材２を厚くする必要もなくなる。
これにより、本発明のガス発生器Ｓは、外筒材２の製造コストを抑えることができ、また、外筒材２の厚さｄを必要以上に厚くするものでないので、小型・軽量化、及び低価格を図ったものを提供できる。
しかも、環状突起１８の突出量ｆ、環状溝１６の傾斜角度θ及び深さｈ、外筒材２の厚さｄを適宜選択することで、外筒材２の各開口側５，６の密封閉鎖と、各蓋部材３，４の位置決めを確実に行え、しかも、ガス発生剤１３の燃焼で発生する高温、高圧ガスによって、各蓋部材３，４が外筒材２から抜け出ることも防げる。即ち、環状溝１６の傾斜角度θ＝４０〜５０°の範囲となし、外筒材２の厚さｄと環状溝１６の深さｈの比率ｈ／ｄを２以下となし、環状突起ｆの突出量ｆを０．７０〜１．００×ｄとすることが好ましい。
また、環状溝１６をＶ字形状に形成することで、絞り加工による過剰な負荷を各蓋部材３，４に加えることなく、環状突起１８をスムーズに環状溝１６の各テーパー形状１６ａ，１６ｂに倣わすことができる。
さらに、環状突起１８を絞り加工で形成することで、簡単な加工によって、外筒材２の各開口側５，６と各蓋部材３，４との各間を密封閉鎖できると同時に、各蓋部材３，４を外筒材２の各開口側５，６に位置決めできる。
また、絞り加工を施すとき、各蓋部材３，４のフランジ１５によって、外筒材２の各開口端側２ｂの変形を規制することで、環状突起１８を確実に環状溝１６の各テーパー形状１６ａ，１６ｂに倣わすことができる。
なお、本発明のガス発生器Ｓは、側面衝突用のエアバッグを膨張展開させるものについて説明したが、これに限定されるものでなく、インストルメントパネルに組み込まれる助手席用のエアバッグを膨張展開させるものにも適用できる。
助手席用のガス発生器の一例としては、第５図に示すものがある。なお、第５図において、第１図〜第４図と同一符号は同一部材を示す。第５図のガス発生器Ｐは、各蓋部材３，４を外筒材２の各開口側５，６に嵌挿することで、長尺円筒状のハウジング１を構成する。ハウジング１内の密封空間Ｐ１には、その軸方向にわたって円筒状のフィルター材９を配置し、フィルター材９内にガス発生剤１３を装填する。また、点火手段３４は、蓋部材４に装着される点火具４５と、該点火具４５に対峙しフィルター材９内に装入した伝火剤４６とでなる。そして、各蓋部材３，４には、環状溝１６を形成し、該環状溝１６内に弾性リング１７を装着する。また、外筒材２の各開口側５，６に絞り加工を施すことで、環状突起１８を環状溝１６内に突出形成する。この環状突起１８は弾性リング１７を環状溝１６に弾接しつつ、該環状溝の形状に倣って嵌め込まれる構造とする。
第５図のガス発生器Ｐは、衝突センサーが自動車の衝突を検出すると、点火具４５を通電発火し、伝火剤４６を着火させる。伝火剤４６の火炎は、フィルター材９内に噴出され、ガス発生剤１３を強制的に着火燃焼させることで、高温ガスを発生させる。そして、高温ガスは、フィルター材９に流入し、ここで冷却とスラグ捕集を経て、所定圧力にて破裂されたバーストプレート１４から各ガス放出孔２ａを通してエアバッグ内に放出される。
このように、助手席用のガス発生器Ｐにおいても、第１図〜第４図に示すものと同様な効果を得ることができる。
本発明のガス発生器Ｓ，Ｐでは、外筒材２の両端を開口するものについて説明したが、一端のみが開口する外筒材２を用いても良い。また、環状溝１６の形状は、Ｖ字形状の限定されるものでなく、断面凹状であれば良く、Ｕ字形状や半円形状のもの等も採用できる。
また、環状溝１６の形状は、第６図に示すものを採用できる。第６図において、環状溝１６は、外筒材２の内周回りに開口するＶ字形状、及びＶ字形状に連続する凹形状から形成される。この環状溝１６では、Ｖ字形状の傾斜角度θをθ＝４０〜５０°の範囲とするのが好ましい。また、外筒材２の厚さｄと環状溝１６の深さｈとの比率ｈ／ｄを２以下とするのが好ましく、環状突起１８の突出量ｆを０．７０〜１．００×ｄとするのが好ましい。そして、弾性リング１７を凹形状内に装着し、外筒材２の外周回りに絞り加工を施すことで、環状突起１８を形成する。この環状突起１８、環状溝１６のＶ字形状に倣って嵌め込まれるとともに、弾性リング１７を凹形状に弾接する。これで、弾性シール１７を過剰に変形、即ち潰すことなく、第１図〜第５図と同様に密封閉鎖、位置決めを確実にでき、しかも抜け止めできる。
なお、第６図の環状溝１６における凹形状部は、断面凹状であれば良く、Ｕ字形状や半円形状の等も採用できる。このとき、環状溝１６を外筒材２に施される絞り加工により、環状突起１８を環状溝１６に強固に係止させるため、環状溝１６の外筒材２の内周側をＶ字形状にすることが好ましく、傾斜角度θ＝４０〜５０°とすることが好ましい。また、Ｕ字形状や半円形状の環状溝１６の深さｈは、外筒材２の内周開口から底までの距離である。
さらに、本発明のガス発生器Ｓ，Ｐでは、１つの点火手段３４によってガス発生剤１３を着火燃焼させるものを説明したが、ハウジング１の蓋部材３にも点火手段を装着することで、即ち、両軸端に点火手段を装着することで、エアバッグの膨張展開を制御可能とする構造も採用できる。
そして、２つの点火手段の通電発火を適宜選択することで、エアバッグの膨張展開を制御する。即ち、各点火手段を同時に通電発火することで、エアバッグを燃焼室内で発生する多量のガスによって急速に膨張展開させる。また、点火手段を時間差をもって通電発火することで、エアバッグを展開初期において燃焼室内で発生する少量のガスによって緩やかに膨張展開させ、微小時間差後、燃焼室内で発生する多量のガスにて急速に膨張展開させる。
産業上の利用可能性
本発明のガス発生器によれば、蓋部材を、外筒材の開口側に位置決めするため、外筒材の内周に段部を加工し、該段部の加工に伴って外筒材を厚くする必要もなくなる。また、外筒材の厚さを必要以上に厚くするものでないので、小型・軽量化、及び低価格を図ったものを提供できる。さらに、ガス発生剤の燃焼で発生する高温、高圧ガスによって、蓋部材が外筒材から抜け出ることも防げる。
【図面の簡単な説明】
第１図は、本発明のガス発生器であって、側面衝突用のエアバッグを膨張展開させるものを示す断面図である。第２図は、第１図のＡ−Ａ断面図である。第３図は、第１図のガス発生器における一方のカシメ手段を示す図であって、（ａ）は環状突起を形成する前の状態を示す要部拡大図、（ｂ）は（ａ）のＢ−Ｂ断面図、（ｃ）は環状突起を形成した後の状態と示す要部拡大図である。第４図は、第１図のガス発生器における他方のカシメ手段を示す図であって、（ａ）は環状突起を形成する前の状態を示す要部拡大図、（ｂ）環状突起を形成する前の状態を示す要部拡大図である。第５図は、本発明のガス発生器であって、助手席用のエアバッグを膨張展開させるものを示す断面図である。第６図は、本発明のガス発生器の変形例を示す断面拡大図である。第７図は、従来のガス発生器を示す断面図である。Technical field
The present invention relates to a gas generator suitable for inflating and deploying a side collision or passenger airbag.
Background art
FIG. 7 shows an example of a gas generator for inflating and deploying a side collision or passenger airbag.
The gas generator shown in FIG. 7 is mainly for inflating and deploying an airbag for side collision, and closes a long cylindrical outer cylindrical member 52 having one end opened and an opening side of the outer cylindrical member 52. A housing 51 including a lid member 53 is provided. In the housing 51, the lid member 53 is inserted into the inner peripheral step portion 52 a of the outer cylinder 52, and the open end 52 b of the outer cylinder 52 is bent inward, so that the lid 53 is formed on the opening side of the outer cylinder 52. Position. The lid member 53 has an annular groove 53a that opens around the inner periphery of the outer cylinder 52, and a seal ring 54 is mounted in the annular groove 53a. When the open end 52b of the outer cylinder 52 is bent, the seal ring 54 is elastically contacted with the inner periphery of the outer cylinder 52 and the annular groove 53a to seal the inside of the housing 51.
Further, inside the housing 51, a combustion chamber 56 and a cooling filtration chamber 57 are formed in the axial direction of the housing 1 by a partition ring plate 55. A gas generating agent 58 that generates a high-temperature gas by combustion is loaded in the combustion chamber 56, and a cylindrical filter that filters and cools the high-temperature gas generated by the combustion of the gas generating agent 58 is mounted in the cooling filtration chamber 57. Filter material 59 is mounted. Further, an igniter 60 for ejecting a flame into the combustion chamber 52 is mounted on the bottom 52 c of the outer cylinder 52.
In this gas generator, an igniter 60 is energized and ignited by a collision signal from a collision sensor, and this flame is ejected into a combustion chamber 56 to ignite and burn a gas generating agent 58, thereby producing a large amount of high-temperature gas. Generate rapidly. The high-temperature gas generated in the combustion chamber 52 flows into the cooling and filtering chamber 57 through the partitioning ring plate 55, and then flows into the filter material 59, where the gas flows through the cooling and slag collection, whereupon each gas in the housing 51 is cooled. It is discharged into the airbag from the discharge hole 51a. The airbag is rapidly inflated and deployed by a large amount of clean gas discharged from each gas discharge hole 51a.
By the way, in recent years, in the technical field of gas generators, low-cost gas generators have been demanded in addition to reduction in size and weight.
From this viewpoint, in the conventional gas generator, since the lid member 53 is positioned on the opening side of the outer cylinder 52, it is necessary to separately process the inner peripheral step 52a on the outer cylinder 52, which reduces the manufacturing cost. It is difficult to reduce.
Processing the inner peripheral step 52a reduces the thickness of the outer tubular member 52 at this portion, resulting in a structure that is weak in strength. Therefore, in order to provide a structure that can withstand the high-temperature and high-pressure gas generated in the housing 51 due to the combustion of the gas generating agent 58, it is necessary to increase the thickness of the entire outer cylinder 52 only by the inner peripheral step 52a.
As a result, in the conventional gas generator, the processing cost of the inner peripheral step 52a is increased by processing the inner peripheral step 52a, and the overall thickness of the outer cylindrical member 52 is increased only by the inner peripheral step 52a to reduce the size and size of the conventional gas generator. It is difficult to achieve weight reduction.
An object of the present invention is to provide a low-cost gas generator while reducing the size and weight.
Disclosure of the invention
A gas generator according to the present invention (claim 1) has an elongated cylindrical outer cylinder member having at least one end opened, and is inserted into the outer cylinder member to close an opening side of the outer cylinder member. A housing is constituted by the lid member. A gas generating agent that generates a high-temperature gas by combustion is loaded in the outer tube member, and a filter member that cools the high-temperature gas and collects slag is disposed. The housing is provided with one or more ignition means for igniting and burning the gas generating agent in the outer cylinder. Further, in the gas generator of the present invention, an annular groove that opens around the inner periphery of the outer cylindrical member is formed in the lid member, and an elastic ring is mounted in the annular groove. Then, the opening side of the outer cylinder material is projected into the annular groove to form an annular projection, and the annular projection is fitted into the annular groove while elastically contacting the elastic ring while following the shape of the annular groove.
As a result, the annular projection elastically contacts the elastic ring to the annular groove of the lid member to seal and close the inside of the outer cylindrical member from the outside. Further, the annular projection elastically contacts the elastic ring with the annular groove, and at the same time, is fitted according to the shape of the annular groove, and abuts against the annular groove from the inside. Thus, the movement of the lid member in the outer cylinder is restricted by the contact between the annular groove and the annular projection, and the lid is positioned at the opening side of the outer cylinder.
For this reason, in the gas generator of the present invention, the cooperation of the annular projection and the annular groove seals and closes the inside of the outer cylinder from the outside, and simultaneously positions the lid member on the opening side of the outer cylinder. .
Therefore, in order to position the lid member on the opening side of the outer cylinder, it is not necessary to form a step on the inner periphery of the outer cylinder and increase the thickness of the outer cylinder with the processing of the step.
In addition, by appropriately selecting the amount of protrusion of the annular projection, the shape of the annular groove, and the thickness of the outer cylinder, the hermetic closure of the outer cylinder and the positioning of the lid member can be reliably performed, and the gas generating agent can be used. The high-temperature, high-pressure gas generated by the combustion can also prevent the lid member from falling out of the outer cylinder.
In the gas generator according to the present invention (claim 2), the annular projection is formed by projecting the annular projection into the annular groove by drawing work performed around the outer periphery of the outer cylinder material. To form.
With this, the sealing and closing of the inside of the outer cylinder and the positioning of the lid member can be performed by simple processing of drawing around the outer circumference of the outer cylinder.
In the gas generator according to the present invention (Claim 3), a V-shape in which the annular groove is opened around the inner periphery of the outer cylinder is provided in the first or second embodiment. It is a shape.
Accordingly, when forming the annular projection, the annular projection can be made to follow the V-shape of the annular groove without applying an excessive load to the lid member.
In the gas generator according to the present invention (claim 4), the inclination angle θ of the annular groove is set to θ = 40 to 50 ° and the thickness d of the outer cylinder And the depth h of the annular groove is not more than 2, and the protrusion amount f of the annular projection is f = 0.70 to 1.00 × d.
With this, it is possible to reliably perform sealing and closing of the inside of the outer cylinder and to position the lid member to the opening side of the outer cylinder at the same time, and at the same time, move the lid inside the outer cylinder by the high temperature and high pressure gas generated by the combustion of the gas generating agent. Getting out of the box can be prevented more reliably.
In the gas generator according to the present invention (claim 5), when the annular projection is formed on the cover member in the manner described in claim 1, it is engaged with the opening end side of the outer cylindrical member. It is formed by forming a flange.
Thereby, the engagement between the flange of the lid member and the opening end side of the outer cylindrical member prevents the opening end side of the outer cylindrical member from being deformed such as expanding in diameter, and the annular protrusion is securely formed in the annular groove. It can follow the shape.
BEST MODE FOR CARRYING OUT THE INVENTION
A gas generator according to an embodiment of the present invention will be described with reference to FIGS.
The gas generator S shown in FIGS. 1 and 2 mainly inflates and deploys an air bag for side collision, and includes a long cylindrical outer cylinder 2 having both ends opened, and each opening of the outer cylinder 2. Lid members 3 and 4 for closing the sides 5 and 6 are provided, and the members 1 to 4 constitute the housing 1. The gas generator S includes a caulking means 7 for sealing and closing each opening side 5, 6 of the outer cylinder 2 and positioning the lid members 3, 4 on the respective opening sides 5, 6 of the outer cylinder 2. 8 is provided. Further, the gas generator S includes a cylindrical filter material 9, a gas generating agent 13, and an ignition unit 34.
The housing 1 is configured by fitting the respective lid members 3 and 4 into the respective opening sides 5 and 6 of the outer cylindrical member 2, and has a structure in which a sealed space P <b> 1 is formed inside by the respective caulking means 7 and 8. . The outer cylinder member 2 has a plurality of gas discharge holes 2a communicating the sealed space P1 and the airbag. Each gas discharge hole 2a is opened at a position where the filter material 9 in the axial direction of the outer cylinder 2 is disposed, and is formed at predetermined intervals in the circumferential direction and the axial direction of the outer cylinder 2. Each gas discharge hole 2a is closed by a burst plate 14 attached to the inner periphery of the outer cylinder 2. The burst plate 14 is formed of a metal foil such as aluminum, and plays a role in preventing moisture inside the housing 1 and adjusting the internal pressure. The lid members 3 and 4 are formed with a step 19 to be inserted into each of the opening sides 5 and 6 in the outer cylindrical member 2. The step 19 has a depth equal to the thickness d of the outer cylinder 2. Further, flanges 15 are formed on the lid members 3 and 4 so as to protrude in the radial direction of the outer cylinder 2, and the inner side 15 a of each flange 15 is engaged with each opening end 2 b of the outer cylinder 2. . The outer tube member 2 and the lid members 3 and 4 are made of a steel material such as stainless steel having excellent heat resistance and pressure resistance.
Each of the caulking means 7 and 8 is provided on each of the opening sides 5 and 6 of the outer cylindrical member 2.
The caulking means 7 includes an annular groove 16, an elastic ring 17, and an annular projection 18, as shown in FIG.
The annular groove 16 is formed in the lid member 3 and opens around the inner circumference on the opening side 5 of the outer tubular member 2 continuously with the flange 15. The annular groove 16 is formed in a V-shape that opens on the inner periphery of the outer cylinder 2. The V-shape of the annular groove 16 has tapered shapes 16a and 16b that expand toward the inner periphery of the outer cylindrical member 2 at a predetermined inclination angle θ, width t and depth h [FIG. (A)].
The elastic ring 17 is mounted in the annular groove 16 and is in contact with the inner periphery of the outer cylindrical member 2 on the opening side 5. As the elastic ring 17, it is preferable to use an O-ring in which an elastic material such as urethane rubber, nitrile rubber, fluorine rubber, and ethylene propylene rubber is formed into a ring shape.
The annular projection 18 is formed by drawing the outer periphery of the outer cylinder 2 around the opening 5 of the outer cylinder 2 into the annular groove 16. In this drawing, the opening 5 is projected into the annular groove 16 while the inner diameter of the opening 5 of the outer cylinder 2 is reduced and deformed. In addition, the annular projection 18 elastically contacts the elastic ring 17 to each of the tapered shapes 16a and 16b of the annular groove 16 by drawing, and is fitted following the tapered shapes 16a and 16b. At this time, since the annular groove 16 is formed in a V-shape, the annular protrusion 18 smoothly follows the respective tapered shapes 16a and 16b of the annular groove 16 without applying an excessive load due to drawing to the lid member 3. I can do it. Also, when drawing is performed on the opening side 5 of the outer cylindrical member 2, the opening end side 2 b of the outer cylindrical member 2 is deformed following the inner side 15 a of the lid member 3 continuously from the tapered shape 16 a of the annular groove 16. Is done. Thus, the flange 15 of the lid member 3 restricts the opening end 2b from being deformed by the engagement with the opening end 2b of the outer cylindrical member 2 such that the opening end 2b expands in diameter. The tapered shape 16a, 16b of the annular groove 16 is surely made to follow (see FIG. 3 (c)).
The annular projection 18 is fitted into the annular groove 16 and abuts on each of the tapered shapes 16 a and 16 b from the inside of the annular groove 16 so that the lid member 3 is immovable and positioned on the opening side 5 of the outer cylinder 2. . The annular projection 18 elastically contacts the elastic ring 17 with the annular groove 16 to seal and close the gap between the opening 5 of the outer cylinder 2 and the lid member 3. The protrusion amount f of the annular projection 18 is determined by the relationship between the inclination angle θ of the annular groove 16 and the ratio of the thickness d of the outer cylinder 2 to the depth h of the annular groove 16. The sealing and closing of the opening side 5 of the cylindrical member 2 and the positioning of the lid member 3 can be ensured, and the high temperature and high pressure gas generated in the housing 1 prevents the lid member 3 from falling out of the outer cylindrical member 2. I do. The thickness d of the outer cylindrical member 2 is such that the annular projection 18 can be formed by drawing and can withstand high-temperature and high-pressure gas generated in the housing 1.
The inclination angle θ of the annular groove 16, the ratio h / d of the depth h of the annular groove 16 to the thickness d of the outer cylindrical member 2, and the projection amount f of the annular projection 18 can be hermetically closed and positioned. It can be done, and it can be retained.
(1) The inclination angle θ of the annular groove 16 is preferably in the range of θ = 40 to 50 °.
With respect to the inclination angle θ, if the inclination angle is increased, the locking force between the annular projection 18 and the annular groove 16 cannot be sufficiently obtained. When performing drawing, an excessive load acts on each of the lid members 3, 4 and the like, causing distortion and the like. From such a viewpoint, the inclination angle θ at which the locking force can be sufficiently obtained and the distortion does not occur is set to θ = 40 to 50 °.
In the inclination angle θ, it is not always necessary to make the inclination angle θa on the taper shape 16a side equal to the inclination angle θb on the taper shape 16b side. However, in order to prevent each of the lid members 3 and 4 from falling out of the outer cylindrical member 2, it is particularly preferable to set the inclination angle θb to 40 to 50 °. In addition, it is preferable that the inclination angles θa and θb are substantially the same so that the force of the drawing process is uniformly applied to each of the lid members 3 and 4 during the drawing process on the outer cylindrical member 2.
(2) It is preferable that the ratio of the depth h of the annular groove 16 to the thickness d of the outer cylindrical member 2 is h / d = 2 or less.
On the other hand, if the ratio h / d is too large, the depth h of the annular groove 16 increases, and the strength of each of the lid members 3 and 4 decreases. The ratio h / d can be appropriately selected as long as the locking force between the annular projection 18 and the annular groove 16 can be obtained, but is preferably 1 or more.
(3) The protrusion amount f of the annular protrusion 18 is preferably set to 0.70 to 1.00 × d.
If the protrusion amount f is less than the range of 0.70 to 1.00 × d, the locking force between the annular protrusion 18 and the annular groove 16 may not be sufficiently obtained. However, there is a possibility that the crimping strength due to the annular projection 18 is reduced. From this point of view, f = 0.70 to 1.00 × d is set as the protrusion amount f that can sufficiently obtain the locking force and the crimping strength.
Thus, the caulking means 7 elastically deforms the elastic ring 17 by the cooperation of the annular groove 16 and the annular protrusions 18 fitted along the respective tapered shapes 16a and 16b of the annular groove 16, thereby forming the outer cylindrical member. At the same time, the gap between the opening side 5 of the outer cylinder 2 and the lid member 3 is hermetically closed, and at the same time, the lid member 3 is positioned on the opening side 5 of the outer tubular member 2 to prevent it from falling off (see FIG. 3 (c)).
As shown in FIG. 4, the swaging means 8 includes an annular groove 16, an elastic ring 17, and an annular projection 18 similar to the swaging means 7. Also in the caulking means 8, the elastic ring 17 is elastically deformed by the cooperation of the annular groove 16 and the annular protrusion 18 fitted along the respective tapered shapes 16 a and 16 b of the annular groove 16, and the outer cylindrical member 2 is formed. The lid member 4 is positioned at the opening side 6 of the outer tubular member 2 to prevent the lid member 4 from coming off at the same time that the space between the opening side 6 and the lid member 4 is hermetically closed (see FIG. 4 (b)).
The caulking means 7 and 8 form a sealed space P1 inside the housing 1 by hermetically closing between the opening sides 5 and 6 of the outer cylindrical member 2 and the lid members 3 and 4, respectively. .
In a sealed space P1 in the housing 1, a filter material 9 is disposed, and a gas generating agent 13 is loaded. Further, an ignition means 34 is mounted on the lid member 4 of the housing 1.
The filter member 9 is disposed at a middle portion of the outer cylinder member 2 and forms a first combustion chamber 10 and a second combustion chamber 11 with each of the lid members 3 and 4. A third combustion chamber 12 penetrating in the axial direction of the housing 1 is formed in the filter material 9, and the first and second combustion chambers 10 and 11 communicate with each other through the third combustion chamber 12. The filter material 9 is manufactured at low cost by forming an aggregate of a knitted wire mesh, a plain woven wire mesh, a crimp woven metal wire, or the like into a cylindrical shape. In addition, the filter material 9 can also be manufactured by winding a wire mesh a plurality of times.
Further, the filter material 9 is supported by the filter support 21, and is positioned by a drawing process performed around the outer circumference of the outer cylindrical material 2. The filter support 21 includes an inner cylindrical member 22 inserted around the outer periphery of the filter member 9, and partition caps 23 and 24 fitted on both ends of the outer periphery of the inner cylindrical member 22. A plurality of gas passage holes 22a are formed in the inner cylindrical member 22. The partition caps 23 and 24 are fitted on the inner circumference of the outer cylinder 2 to form an annular gas passage space P2 between the inner cylinder 22 and the outer cylinder 2. These partition caps 23, 24 are formed with opening holes 23A, 24A that communicate the first and second combustion chambers 10, 11 and the third combustion chamber 12, respectively. Thus, the filter support 21 restricts the filter material 9 from moving in the radial direction of the housing 1 by inserting the caps 23 and 24 into the inner circumference of the outer cylindrical material 2. Further, the filter support 21 closes the shaft end of the filter material 2 by the caps 23 and 24 so that the high-temperature gas generated in the combustion chambers 10 and 11 can be opened by the opening holes 23A of the caps 23 and 24. , 24A into the third combustion chamber 12 and restricts the flow of the high-temperature gas directly into each shaft end of the filter material 9 or into the gas passage space P2.
Then, the filter support 21 is brought into contact with the respective projections 25 and 26 projecting from the inner periphery of the outer tubular member 2 by drawing, and is positioned. The projections 25 and 26 come into contact with the caps 23 and 24 from the respective shaft end sides of the filter material 9 and support the filter support 21 with the filter support 21 interposed therebetween. As a result, the filter material 9 is positioned at a middle position of the outer cylindrical material 2 by the filter support 21 abutting on the projections 25 and 26. The projections 25 and 26 abut against the caps 23 and 24 without any gap, and the high-temperature gas generated in the combustion chambers 10 and 11 flows from between the caps 23 and 24 and the inner periphery of the outer cylinder 2. The outflow directly into the gas passage space P2 is restricted (see FIG. 3 (c) and FIG. 4 (b)).
The gas generating agent 13 generates high-temperature gas by combustion, and is charged over the first to third combustion chambers 10 to 12. Further, the gas generating agent 13 is prevented from being powdered due to vibration by the cushion members 31 and 32. The cushion member 31 is mounted between the gas generating agent 13 of the first combustion chamber 10 and the cushion pressing member 33 of the lid member 4. The cushion member 31 has a cross-shaped notch for reliably transmitting the power of the flame from the ignition means 34 to the gas generating agent 13 without delay. The cushion member 32 is mounted between the gas generating agent 13 of the second combustion chamber 11 and the lid member 32. Each of the cushion members 31 and 32 can be formed using an elastic material such as silicone rubber or silicone foam.
The igniting means 34 is composed of only an igniter that energizes and ignites, and is attached to the lid member 4 from inside the housing 1. The ignition means 34 protrudes toward the first combustion chamber 10 and is in contact with the cushion material 31 through the cushion pressing material 33. The ignition means 34 energizes and ignites based on a collision detection signal from the collision sensor, and forcibly ignites the gas generating agent 13 in the first combustion chamber 3 by ejecting a flame into the first combustion chamber 10. Burn.
Next, the operation of the gas generator S will be described.
When the collision sensor detects the collision of the vehicle, the gas generator S energizes and ignites the ignition means 34. After the flame of the ignition means 34 ruptures and opens the cushion material 31, the flame is ejected into the first combustion chamber 10 to ignite and burn the gas generating agent 13, thereby generating a high-temperature gas.
The high-temperature gas generated in the first combustion chamber 10 is guided into the third combustion chamber 12 by the partition cap 23 without directly flowing into the gas passage space P2 and the like, and flows into the filter material 9, where the gas flows. After cooling and collecting slag, it is discharged into the gas passage space P2. At this time, in the third combustion chamber 12, the gas generating agent 13 is ignited and burned by heat of the high-temperature gas flowing from the first combustion chamber 10 to generate high-temperature gas. Further, in the combustion in the third combustion chamber 12, the gas generating agent 13 is sequentially burned from the first combustion chamber 10 side, and moves to the second combustion chamber 11 side.
When the combustion in the first combustion chamber 10 proceeds and the inside of the housing 1 rises to a predetermined pressure, the burst plate 14 ruptures, and clean gas made uniform in the gas passage space P2 passes through each gas discharge hole 2a. Released into the airbag 1. Thus, the airbag starts gently inflating and deploying with a small amount of gas generated in the first combustion chamber 40 and the like.
Further, as the pressure in the housing 1 increases, the high-temperature and high-pressure gas acts on each of the lid members 3 and 4. These lid members 3 and 4 try to escape from the inside of the outer tubular member 2 by the action of the high-temperature and high-pressure gas, but are prevented from coming off by the tapered shape 16 b of the annular groove 16 abutting against the annular projection 18. [See FIG. 3 (c) and FIG. 4 (b)].
Subsequently, when the combustion in the first combustion chamber 10 and the third combustion chamber 12 proceeds, the gas generating agent 13 in the second combustion chamber 11 is ignited and burned with a small time difference from the start of combustion in the first combustion chamber 10. You. The combustion in the second combustion chamber 11 is performed by a flame, heat, or the like that propagates and is ejected from the third combustion chamber 12, and ignites and burns the gas generating agent 13 to generate a high-temperature gas.
The high-temperature gas generated in the second combustion chamber 11 is guided into the third combustion chamber 12, flows into the filter material 9, and then flows out into the gas passage space P2 through cooling and slag collection. At this time, the combustion in the housing 1 is the entire combustion in each of the combustion chambers 10 to 12, and the pressure in the housing 1 reaches the maximum pressure.
The clean gas that has flowed into the gas passage space P2 is discharged from each gas discharge hole 2a into the airbag. The airbag is shifted to rapid inflation and deployment by a large amount of clean gas generated in each of the combustion chambers 10 to 11 and having reached a maximum pressure.
When the inside of the housing 1 reaches the maximum pressure, the high-temperature and high-pressure gas acts on each of the lid members 3 and 4, but the tapered shape 16b of the annular groove 16 comes into contact with the annular projection 18 as described above. Thus, the lid members 3 and 4 are prevented from coming off.
As a result, the airbag starts inflating and deploying gently by the small amount of gas generated in the first combustion chamber 10 or the first and third combustion chambers 10 and 12 in the initial stage of deployment, and after a short time, A large amount of gas having the highest pressure generated in the combustion chambers 10 to 12 causes rapid expansion and development.
As described above, in the gas generator S of the present invention, the inside of the outer cylindrical member 2 is hermetically closed from the outside by the cooperation of the annular protrusion 18 and the annular groove 16, and at the same time, each of the lid members 3, 4 is closed. Can be positioned on each of the opening sides 5, 6. Therefore, in order to position each of the lid members 3 and 4 on the opening sides 5 and 6 of the outer cylinder 2, a step is formed on the inner periphery of the outer cylinder 2, and the outer cylinder is formed with the processing of the step. There is no need to make 2 thicker.
As a result, the gas generator S of the present invention can reduce the manufacturing cost of the outer cylinder member 2 and reduce the size and weight of the outer cylinder member 2 because the thickness d of the outer cylinder member 2 is not increased more than necessary. And a low-priced product can be provided.
In addition, by appropriately selecting the protrusion amount f of the annular projection 18, the inclination angle θ and the depth h of the annular groove 16, and the thickness d of the outer cylinder member 2, the sealing of each opening side 5, 6 of the outer cylinder member 2 is performed. The closure and the positioning of the lid members 3 and 4 can be reliably performed, and the lid members 3 and 4 can be prevented from coming out of the outer cylinder 2 by the high-temperature and high-pressure gas generated by the combustion of the gas generating agent 13. That is, the inclination angle θ of the annular groove 16 is in the range of 40 to 50 °, the ratio h / d of the thickness d of the outer cylindrical member 2 to the depth h of the annular groove 16 is 2 or less, It is preferable that the protrusion amount f be 0.70 to 1.00 × d.
Further, by forming the annular groove 16 in a V-shape, the annular projection 18 is smoothly formed on each of the tapered shapes 16a and 16b of the annular groove 16 without applying an excessive load due to the drawing process to each of the lid members 3 and 4. You can imitate.
Further, by forming the annular projection 18 by drawing, the gap between each of the opening sides 5, 6 of the outer cylindrical member 2 and each of the lid members 3, 4 can be hermetically closed by simple processing, and at the same time, each lid can be closed. The members 3 and 4 can be positioned on the respective opening sides 5 and 6 of the outer cylinder 2.
Further, when drawing is performed, the deformation of each opening end side 2b of the outer cylindrical member 2 is regulated by the flange 15 of each of the lid members 3 and 4, so that the annular protrusion 18 is securely formed in each of the tapered shapes of the annular groove 16. 16a, 16b.
Although the gas generator S of the present invention has been described for inflating and deploying the side collision airbag, the invention is not limited to this, and the passenger side airbag incorporated in the instrument panel may be inflated. It can be applied to what is deployed.
FIG. 5 shows an example of a gas generator for a passenger seat. In FIG. 5, the same reference numerals as those in FIGS. 1 to 4 denote the same members. The gas generator P in FIG. 5 forms the long cylindrical housing 1 by fitting the respective lid members 3 and 4 into the respective opening sides 5 and 6 of the outer cylindrical member 2. A cylindrical filter material 9 is arranged in the sealed space P1 in the housing 1 along the axial direction thereof, and a gas generating agent 13 is loaded in the filter material 9. The igniting means 34 includes an igniter 45 attached to the lid member 4 and a transfer agent 46 that is opposed to the igniter 45 and is charged in the filter member 9. An annular groove 16 is formed in each of the lid members 3 and 4, and an elastic ring 17 is mounted in the annular groove 16. Also, the annular projections 18 are formed to project into the annular grooves 16 by drawing the respective opening sides 5, 6 of the outer cylinder 2. The annular projection 18 has a structure in which the elastic ring 17 elastically contacts the annular groove 16 and is fitted according to the shape of the annular groove.
In the gas generator P of FIG. 5, when the collision sensor detects the collision of the automobile, the ignition device 45 is energized and fired, and the transfer agent 46 is ignited. The flame of the transfer agent 46 is ejected into the filter material 9 and the gas generating agent 13 is forcibly ignited and burned, thereby generating a high-temperature gas. Then, the high-temperature gas flows into the filter material 9, where it is cooled and slag collected, and then discharged from the burst plate 14 ruptured at a predetermined pressure through the gas discharge holes 2 a into the airbag.
Thus, the same effect as that shown in FIGS. 1 to 4 can be obtained also in the gas generator P for the passenger seat.
In the gas generators S and P according to the present invention, the gas generators S and P are described in which the both ends of the outer cylinder 2 are opened. However, the outer cylinder 2 having only one end opened may be used. Further, the shape of the annular groove 16 is not limited to the V-shape, but may be any shape as long as it is concave in cross section, and a U-shape or a semicircular shape may be employed.
The shape of the annular groove 16 can be the one shown in FIG. In FIG. 6, the annular groove 16 is formed in a V-shape that opens around the inner periphery of the outer cylindrical member 2 and a concave shape that is continuous with the V-shape. In the annular groove 16, it is preferable that the V-shaped inclination angle θ be in the range of θ = 40 to 50 °. Further, the ratio h / d of the thickness d of the outer cylindrical member 2 to the depth h of the annular groove 16 is preferably set to 2 or less, and the projection amount f of the annular projection 18 is set to 0.70 to 1.00 × d. It is preferred that Then, the annular ring 18 is formed by mounting the elastic ring 17 in the concave shape and drawing around the outer periphery of the outer cylindrical member 2. The annular projection 18 and the annular groove 16 are fitted to follow the V-shape, and the elastic ring 17 elastically contacts the concave shape. Thus, the sealing and closing and positioning can be reliably performed as in FIGS. 1 to 5 without being excessively deformed, that is, crushed, of the elastic seal 17, and can be prevented from coming off.
The concave portion of the annular groove 16 in FIG. 6 only needs to be concave in cross section, and may be U-shaped or semicircular. At this time, the inner peripheral side of the outer cylindrical member 2 of the annular groove 16 is formed into a V-shape in order to firmly lock the annular projection 18 to the annular groove 16 by drawing the annular groove 16 into the outer cylindrical member 2. It is preferable to set the inclination angle θ to 40 to 50 °. The depth h of the U-shaped or semicircular annular groove 16 is a distance from the inner peripheral opening of the outer cylindrical member 2 to the bottom.
Further, in the gas generators S and P of the present invention, the gas generator 13 is ignited and burned by one ignition means 34, but the ignition means is also attached to the lid member 3 of the housing 1, that is, Also, a structure can be adopted in which the inflation and deployment of the airbag can be controlled by attaching ignition means to both shaft ends.
Then, the inflation and deployment of the airbag is controlled by appropriately selecting the energization and firing of the two ignition means. That is, by energizing and firing the respective ignition means simultaneously, the airbag is rapidly expanded and deployed by a large amount of gas generated in the combustion chamber. Also, by energizing and igniting the ignition means with a time lag, the airbag is gradually expanded and deployed by a small amount of gas generated in the combustion chamber in the initial stage of deployment, and after a small time lag, rapidly expanded by a large amount of gas generated in the combustion chamber. Inflate and deploy.
Industrial applicability
According to the gas generator of the present invention, in order to position the lid member on the opening side of the outer cylinder, a step is formed on the inner periphery of the outer cylinder, and the outer cylinder is formed with the processing of the step. There is no need to make it thicker. In addition, since the thickness of the outer tubular member is not made unnecessarily thick, it is possible to provide a small, lightweight, and low-priced one. Furthermore, the high temperature and high pressure gas generated by the combustion of the gas generating agent can prevent the lid member from falling out of the outer cylinder.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a gas generator of the present invention, which expands and deploys an airbag for side collision. FIG. 2 is a sectional view taken along the line AA of FIG. FIG. 3 is a view showing one caulking means in the gas generator shown in FIG. 1, wherein (a) is an enlarged view of a main part showing a state before an annular projection is formed, and (b) is (a) (C) is a main part enlarged view showing a state after an annular projection is formed. Fig. 4 is a view showing the other caulking means in the gas generator of Fig. 1, wherein (a) is an enlarged view of a main part showing a state before forming an annular projection, and (b) forming an annular projection. It is a principal part enlarged view which shows the state before performing. FIG. 5 is a cross-sectional view showing a gas generator of the present invention, which expands and deploys an airbag for a passenger seat. FIG. 6 is an enlarged sectional view showing a modification of the gas generator of the present invention. FIG. 7 is a sectional view showing a conventional gas generator.