JP3620888B2 - Actuator capable of multi-stage positioning - Google Patents

Description

【００１８】
即ち、何れのポート３５、４０にも圧縮空気の供給を停止している状態では、外側、内側両ピストン３１、３７の何れにも上昇方向の力が付与されない。従って、上記ロッド１０が閉鎖ばね１４の弾力により下降し切り、上記弁体９が上記流通孔８を完全に閉じる。次に、第一ポート３５に圧縮空気を供給し、第二ポート４０への圧縮空気の供給を停止した状態では、上記内側ピストン３７下面の突部３８と端板３２の上面とを当接させた状態のまま、上記外側ピストン３１がＬ_３１分だけ上昇する。この結果、上記弁体９が上記流通孔８の開口縁部からＬ_３１分だけ離れる。次に、第一ポート３５への圧縮空気を停止し、第二ポート４０に圧縮空気を供給した状態では、上記端板３２の下面とボルト３４の上端面とを当接させた状態のまま、上記内側ピストン３７がＬ_３７分だけ上昇する。この結果、上記弁体９が上記流通孔８の開口縁部からＬ_３７分だけ離れる。更に、第一、第二両ポート３５、４０に圧縮空気を供給した状態では、上記外側ピストン３１がＬ_３１分だけ上昇するだけでなく、この外側ピストン３１に対して上記内側ピストン３７がＬ_３７分だけ上昇する。この結果、上記弁体９が上記流通孔８の開口縁部からＬ_３１＋Ｌ_３７分だけ離れる。
【００１９】
この様に構成され作用する先発明に係るアクチュエータの場合には、外側ピストン３１と内側ピストン３７とを直径方向に重ねて配置している為、軸方向に亙る寸法を大きくする事なく、ストロークを多段階に調節できる。尚、上記内側ピストン３７の更に内側に第二内側ピストンを設け、この第二内側ピストンも外側ピストン及び内側ピストンと別に変位自在にすれば、ストロークを８段階に調節する事も可能になる。この為の具体的な構造に就いても、前記実願平５−７４５７２号に記載されている。
【００２０】
【発明が解決しようとする課題】
上述の様に構成され作用する先発明に係るアクチュエータの場合、軽量化の為にシリンダケース２９をアルミニウム合金により造ると、外側ピストン３１の変位量Ｌ_３１が低温時と高温時とで大きく異なってしまう。即ち、排気循環装置に組み込まれた状態で使用されるアクチュエータの場合には、エンジンの運転継続に伴って相当に高温になる。従って、上記シリンダケース２９及び外側ピストン３１の温度も相当に高くなり、これら両部材２９、３１の熱膨張量が無視できない程に大きくなる。これら両部材２９、３１を同一材料により造った場合には、上記変位量Ｌ_３１が実際に大きく変動する事はない。
【００２１】
これに対して、軽量化の為、容積が嵩む上記シリンダケース２９をアルミニウム合金により造り、強度を必要とする上記外側ピストン３１を鉄製のままとした場合に、上記変位量Ｌ_３１の変動が大きくなる。具体的には、アルミニウム合金製のシリンダケース２９の熱膨張量が鉄製の外側ピストン３１の熱膨張量に比べて大きくなる為、温度上昇に伴って上記変位量Ｌ_３１が大きくなってしまう。この結果、第一ポート３５に圧縮空気を供給し、上記外側ピストン３１を上昇させると、弁体９が流通孔８の開口縁部から必要以上に離れ、所望以上の排気が流通孔８を通じて吸気流路４（図４）に還流してしまう。本発明の多段位置決めが可能なアクチュエータはこの様な事情に鑑み、軽量化の為にシリンダケースをアルミニウム合金により造った場合にも、温度変化に伴うストロークの変化を小さく抑えるべく、発明したものである。
【００２２】
【課題を解決するための手段】
本発明の多段位置決めが可能なアクチュエータは、前述した先発明に係る多段位置決めが可能なアクチュエータと同様に、シリンダケースと、このシリンダケースの内側に設けられたシリンダ孔と、このシリンダ孔の内側に軸方向に亙って変位自在に嵌装された、円筒状で軸方向に関する一端開口を端板により塞がれた外側ピストンと、上記シリンダケースの軸方向一端部に設けられ、上記シリンダ孔の軸方向一端部で上記外側ピストンの軸方向一端側と対向する部分に圧力流体を給排自在な第一ポートと、上記外側ピストンの内側に、この外側ピストンに対する軸方向に亙る変位を自在として嵌装された内側ピストンと、この内側ピストンの軸方向一端面と上記端板の片面との間に設けられた内側圧力室と、この内側圧力室に圧力流体を給排する為、上記シリンダケースの一部に設けられた第二ポートと、上記外側ピストンの内周面と外周面とを連通させる通孔を含んで構成され、上記内側圧力室と上記第二ポートとを連通させる給排通路とを備える。
【００２３】
更に、本発明の多段位置決めが可能なアクチュエータは、上記外側ピストンの軸方向他端部に固定された係止ブラケットと、この係止ブラケットを構成する、この外側ピストンの内径よりも小さな内径及びこの外側ピストンの外径よりも大きな外径を有する円輪状の主部と、この主部の外径寄り部分で、この外側ピストンの外周面よりも直径方向外方に突出した部分により構成された係合突部と、上記シリンダ孔の軸方向他端部内周面に、このシリンダ孔の内周面よりも直径方向外方に突出する状態で形成され、その内側に上記係合突部を進入させた、この係合突部の外径よりも大きな内径及びこの係合突部の軸方向寸法よりも大きな軸方向寸法を有する係合凹部とを備える。そして、上記内側ピストンの軸方向他端面に、上記係止ブラケットの主部の内径側を緩く挿通したロッドの端面を突き当て自在としており、上記外側ピストンは、この係合凹部の軸方向寸法と上記係合突部の軸方向寸法との差に相当する分だけ軸方向に亙って変位自在としている。又、上記内側ピストンは上記外側ピストンの内側で、この内側ピストンの軸方向寸法と、上記端板と上記主部の内径寄り部分でこの外側ピストンの内周面よりも直径方向に突出した部分との間隔との差に相当する分だけ軸方向に亙って変位自在としている。
【００２４】
【作用】
上述の様に構成される本発明の多段位置決めが可能なアクチュエータにより、例えば弁体を駆動する為のロッドのストロークを多段階に調節する際の作用は、前述した先発明の場合と同様である。特に、本発明の多段位置決めが可能なアクチュエータの場合には、外側ピストンの変位量を係合凹部の軸方向寸法と上記係合突部の軸方向寸法との差で規制している為、温度上昇に基づくストロークの変化を小さく抑える事ができる。即ち、上記係合凹部の軸方向寸法の絶対値は、シリンダケースの軸方向寸法に比べて遥かに小さい為、このシリンダケースをアルミニウム合金により造り、しかもこのシリンダケースの温度が上昇した場合でも、上記係合凹部の軸方向寸法の増加量は小さい。従って、温度変化に伴う上記外側ピストンの変位量の変動を小さくできる。
【００２５】
【実施例】
図面に沿って本発明の実施例を説明するが、位置及び方向に関する上下左右の表現は説明の便宜上であって、実際の設置状態が図面及び実施例の説明の状態と９０度異なっていても良いし、上下逆であっても良い。図１〜３は本発明の実施例を示している。アルミニウム、鋳鉄等の金属により造られた弁ケース４５の上部内側には、この弁ケース４５の上端面と上部片側面（図１の左側面）とに開口する流通孔８を設けている。排気再循環装置の構成時には、この流通孔８の上流端である上方開口は排気流路５（図４）に、下流端である側方開口は吸気流路４（図４）に、それぞれ通じさせて、再循環流路６（図４〜５）に直列に接続する。
【００２６】
上記流通孔８の上端開口部には、この流通孔８の開閉及び開度の調節を行なう弁体９を設けている。この弁体９の下面中央部にはロッド１０の上端部を結合している。尚、図示の実施例では、これら弁体９とロッド１０とを一体とした、きのこ弁を使用している。このロッド１０は、上記弁ケース４５内に鉛直方向に亙って形成された貫通孔４６内に、摺動自在に挿通されている。そして、このロッド１０の下端部で上記貫通孔４６から下方に突出した部分にばね座４９を固定している。このばね座４９は、合成樹脂、金属等により全体を円輪状に形成されて、中心部に内径が上方に向かう程小さくなるテーパ孔を有する。又、上記ロッド１０の下端部外周面で上記テーパ孔の内側に位置する部分には凹溝４７を、全周に亙り形成している。そして、合成樹脂又は金属により２分割自在なテーパ円筒状に造られて上記テーパ孔の内側に嵌合したコッタ４８の内周面に形成した突条と、上記凹溝４７とを係合させている。従って上記ばね座４９は、上記ロッド１０に対し下方に変位する事はない。
【００２７】
上述の様にしてロッド１０の下端部に支持されたばね座４９と、上記弁ケース４５の内側に形成した隔壁５０の下面との間には、圧縮コイルばねである閉鎖ばね１４を設けている。この閉鎖ばね１４は、上記ばね座４９を介して上記ロッド１０を下方に向け弾性的に押し、上記弁体９に上記流通孔８を閉じる方向の弾力を付与している。上記貫通孔４６は、上記隔壁５０を上下に貫通する状態で設けている。
【００２８】
又、上記ロッド１０の中間部で上記貫通孔４６の下端開口直下位置に、耐熱性ゴム等により造られたシールリング５１を外嵌して、上記貫通孔４６の内周面と上記ロッド１０の外周面との間の隙間を通じて排気が漏洩するのを防止している。又、前記隔壁５０の下面中央部には円筒部５２を形成しており、この円筒部５２の下端部に、合成樹脂又は金属により円筒状に形成された抑え筒５３の上半部を外嵌固定している。そして、この抑え筒５３の下端部に形成した内向フランジ状の鍔部５４により、上記シールリング５１の脱落防止を図っている。上記抑え筒５３の上半部内周面と上記円筒部５２の下半部外周面とは、接着により、或は図示しない凹凸係合により結合して、円筒部５２からの抑え筒５３の抜け止めを図っている。
【００２９】
又、上記隔壁５０の内側には冷却ジャケット５５を設け、この冷却ジャケット５５内に、給水口５６と排水口５７とを通じて、エンジンの冷却水を流通自在としている。この冷却ジャケット５５は、上記ロッド１０の下半部の温度上昇を抑える機能を有する。即ち、エンジンの運転時には、前記排気流路５（図４）を流通する排気から弁体９の上端面に伝えられ、或はこの排気流路５及び前記流通孔８を流通する排気から上記弁体９及びロッド１０に伝達された熱で、このロッド１０の上部の温度が上昇する。但し、上記排気から上記ロッド１０に伝達された熱のうちの多くの部分は、上記冷却ジャケット５５内を流通する冷却水によって持ち去られる。従って、ロッド１０の上半部の温度が上昇しても、このロッド１０の中間部下寄り部分で上記シールリング５１を装着した部分の温度上昇は限られたものとなる。この結果、このシールリング５１の耐久性を十分に確保できる。
【００３０】
又、前記弁ケース４５の下面には、シリンダケース２９ａを結合固定している。このシリンダケース２９ａの内側には、シリンダ孔３０ａを設けている。このシリンダ孔３０ａの内側には有底円筒状の外側ピストン３１ａを、軸方向に亙る変位自在に、且つ気密に嵌装している。上記外側ピストン３１ａの下端は、この外側ピストン３１ａと一体に形成された端板３２ａにより気密に塞いでいる。又、この端板３２ａの下面には直径方向に亙る凹部５８を形成して、上記外側ピストン３１ａの下端面と、上記シリンダケース２９ａの底板部３３ａの上面との間に軸方向隙間を設け、これら各面同士が当接する事を防止している。そして、上記底板部３３ａの中央部には第一ポート３５ａを設けて、上記外側ピストン３１ａの下側に圧縮空気を給排自在としている。
【００３１】
又、上記外側ピストン３１ａの内側には内側ピストン３７ａを、この外側ピストン３１ａに対して軸方向に亙りＬ_３７ａ 分だけ変位を自在に、且つ気密に嵌装している。上記内側ピストン３７ａの下面には円筒部５９を形成して、この内側ピストン３７ａの軸方向一端面である下面と、上記端板３２ａの片面である上面との間に軸方向隙間を設け、前記弁体９が閉じている時でもこれら各面同士が当接する事を防止している。そして、これら両面同士の間に内側圧力室３９ａを設けている。上記シリンダケース２９ａの中間部側面には、この内側圧力室３９ａに圧力流体を給排する為の第二ポート４０ａを設けている。そして、この第二ポート４０ａと上記内側圧力室３９ａとを、給排通路により連通させている。この給排通路は、前記シリンダ孔３０ａの内周面に全周に亙って形成された、リング状通路である凹部４２ｂと、上記外側ピストン３１ａの内周面と外周面とを連通させる通孔４１ａと、上記内側ピストン３７ａの外周面に全周に亙って形成された凹部４２ａと、上記円筒部５９の内周面と外周面とを連通させる通孔４１ｂとを含んで構成される。流通孔８の端部開口を開閉する為の弁体９をその端部に固設したロッド１０は、上記内側ピストン３７ａの上面に、閉鎖ばね１４の弾力に基づいて当接させられている。又、上記外側、内側両ピストン３１ａ、３７ａの上側に存在する空間４３ａは、図示しないフィルタを介して大気に通じている。
【００３２】
更に、前記外側ピストン３１ａの上端部外周面には、係止ブラケット６０を螺合固定している。この係止ブラケット６０は、円輪状の主部６１の下面に円筒部６２を形成している。そして、この円筒部６２の内周面に形成した雌ねじと上記外側ピストン３１ａの上端部外周面に形成した雄ねじとを螺合させる事で、上記外側ピストン３１ａの上端部に固定している。この状態で上記主部６１の直径方向外半部は、上記外側ピストン３１ａの外周面よりも直径方向外方に突出する、外向フランジ状の係合突部６３を構成する。尚、上記ロッド１０の下端部は、上記主部６１の内径側を緩く挿通して、その下端面を上記内側ピストン３７ａの上端面に突き当てている。
【００３３】
一方、前記シリンダ孔３０ａの上端部内周面には係合凹部６４を、このシリンダ孔３０ａの内周面よりも直径方向外方に突出する状態で形成している。即ち、前記シリンダケース２９ａの上端開口部外周縁にその全周に亙って形成した段部６５と前記弁ケース４５の下面との間で、上記係合凹部６４を形成している。そして、この係合凹部６４の内側に、上記係合突部６３を進入させている。上記係合凹部６４の軸方向に亙る厚さ寸法Ｔ_６４は、上記係合突部６３の軸方向に亙る厚さ寸法Ｔ_６３よりも大きい（Ｔ_６４＞Ｔ_６３）。従って前記外側ピストン３１ａは、この係合凹部６４の厚さ寸法Ｔ_６４と上記係合突部６３の厚さ寸法Ｔ_６３との差（Ｔ_６４−Ｔ_６３）に相当する分だけ軸方向に亙って変位自在である。言い換えれば、上記外側ピストン３１ａの変位量Ｌ_３１ａ は、上記厚さ寸法の差（Ｔ_６４−Ｔ_６３）分となる。
【００３４】
上述の様に構成される本発明に係るアクチュエータは、第一、第二両ポート３５ａ、４０ａへの圧縮空気の供給状態を前記表１に示す様に切り換える事で、前記ロッド１０のストロークを（零を含めて）４段階に調節できる。即ち、第一、第二のポート３５ａ、４０ａの何れにも圧縮空気の供給を停止している状態では、外側、内側両ピストン３１ａ、３７ａの何れにも上昇方向の力が付与されない。従って、上記ロッド１０が閉鎖ばね１４の弾力により下降し切り、上記弁体９が上記流通孔８を完全に閉じる。次に、第一ポート３５ａに圧縮空気を供給し、第二ポート４０ａへの圧縮空気の供給を停止した状態では、上記内側ピストン３７ａ下面の円筒部５９の下端縁と端板３２ａの上面とを当接させた状態のまま、上記外側ピストン３１ａが上記Ｌ_３１ａ 分だけ上昇する。この結果、上記弁体９が上記流通孔８の開口縁部からＬ_３１ａ 分だけ離れる。
【００３５】
次に、第一ポート３５ａへの圧縮空気を停止し、第二ポート４０ａに圧縮空気を供給した状態では、前記段部６５と前記係合突部６３の下面とを当接させた状態のまま、上記内側ピストン３７ａがＬ_３７ａ 分だけ上昇する。この結果、上記弁体９が上記流通孔８の開口縁部からＬ_３７ａ 分だけ離れる。
【００３６】
更に、第一、第二両ポート３５ａ、４０ａに圧縮空気を供給した状態では、上記外側ピストン３１ａがＬ_３１ａ 分だけ上昇するだけでなく、この外側ピストン３１ａに対して上記内側ピストン３７ａがＬ_３７ａ 分だけ上昇する。この結果、上記弁体９が上記流通孔８の開口縁部からＬ_３１ａ ＋Ｌ_３７ａ 分だけ離れる。
【００３７】
上述の様に弁体９を駆動する為のロッド１０のストロークを４段階に変更する際の作用は、前述した先発明の場合と同様である。特に、本発明の多段位置決めが可能なアクチュエータの場合には、上記外側ピストン３１ａの変位量Ｌ_３１ａ を前記係合凹部６４の厚さ寸法Ｔ_６４と前記係合突部６３の厚さ寸法Ｔ_６３との差（Ｔ_６４−Ｔ_６３）で規制している為、温度上昇に基づくストロークの変化を小さく抑える事ができる。即ち、上記係合凹部６４の厚さ寸法Ｔ_６４の絶対値は、前記シリンダケース２９ａの軸方向寸法に比べて遥かに小さい。この為、このシリンダケース２９ａをアルミニウム合金により造り、しかもこのシリンダケース２９ａの温度が上昇した場合でも、上記係合凹部６４の厚さ寸法Ｔ_６４の増加量は小さい。従って、温度変化に伴う上記外側ピストン３１ａの変位量Ｌ_３１ａ の変動を小さくできる。
【００３８】
【発明の効果】
本発明の多段位置決めが可能なアクチュエータは、以上に述べた通り構成され作用するので、軸方向に亙る寸法を小さくし、しかもストロークを多段階に変更できると言った、先発明の効果に加え、軽量化の為にシリンダケースをアルミニウム合金により造った場合にも、温度変化に伴うストロークの変化を小さく抑える事ができる。この為、特に高価な構成部品を使用せずに排気再循環装置を構成する事ができ、しかも温度変化に拘らず排気再循環装置の性能を安定させる事ができる。
【図面の簡単な説明】
【図１】本発明の実施例を示す断面図。
【図２】図１の下方から見た図。
【図３】図１の下部拡大図。
【図４】排気再循環装置の回路図。
【図５】従来の流量調整弁の断面図。
【図６】先発明の多段位置決めが可能なアクチュエータを組み込んだ流量調整弁の断面図。
【符号の説明】
１ シリンダ
２ 吸気弁
３ 排気弁
４ 吸気流路
５ 排気流路
６ 再循環流路
７ 流量調整弁
８ 流通孔
９ 弁体
１０ ロッド
１１ 開放ピストン
１２ 開放シリンダ
１３ 蓋片
１４ 閉鎖ばね
１５ 圧力室
１６ 圧縮空気源
１７ 電磁弁
１８ 供給路
１９ 制御器
２０ 変位計
２１ アクセルペダル
２２ 燃料噴射ポンプ
２３ ケーブル
２４ 回転センサ
２５ 温度センサ
２８ ブロック
２９、２９ａ シリンダケース
３０、３０ａ シリンダ孔
３１、３１ａ 外側ピストン
３２、３２ａ 端板
３３、３３ａ 底板部
３４ ボルト
３５、３５ａ 第一ポート
３６、３６ａ 間部分
３７、３７ａ 内側ピストン
３８ 突部
３９、３９ａ 内側圧力室
４０、４０ａ 第二ポート
４１、４１ａ、４１ｂ 通孔
４２、４２ａ、４２ｂ 凹部
４２ｂ＋４１ａ＋４２ａ＋４１ｂ 給排通路
４３、４３ａ 空間
４４ フィルタ
４５ 弁ケース
４６ 貫通孔
４７ 凹溝
４８ コッタ
４９ ばね座
５０ 隔壁
５１ シールリング
５２ 円筒部
５３ 抑え筒
５４ 鍔部
５５ 冷却ジャケット
５６ 給水口
５７ 排水口
５８ 凹部
５９ 円筒部
６０ 係止ブラケット
６１ 主部
６２ 円筒部
６３ 係合突部
６４ 係合凹部
６５ 段部
６６ 変位センサ [0001]
[Industrial application fields]
The actuator capable of multistage positioning according to the present invention is incorporated in, for example, an exhaust gas recirculation device and used to adjust the valve opening in multiple stages.
[0002]
[Prior art]
Part of the exhaust discharged from the combustion chamber of the diesel engine is returned to the intake system, and the inert gas (H₂  O, N₂  , CO₂  Etc.), the generation of nitrogen oxides in the combustion chamber can be suppressed.And , ConstantIncrease the amount of exhaust gas mixed into the air-fuel mixture when traveling at high speed, etc.Etc.Conventionally, an exhaust gas recirculation device (EGR) that reduces the amount of exhaust gas mixed into the air-fuel mixture has been used.
[0003]
FIG. 4 shows the basic configuration of such an exhaust gas recirculation device. An intake port and an exhaust port provided at the top of the cylinder 1 of the diesel engine are opened and closed by an intake valve 2 or an exhaust valve 3, respectively. Further, the downstream end of the intake passage 4 is connected to the intake port, and the upstream end of the exhaust passage 5 is connected to the exhaust port. The upstream end of the recirculation flow path 6 is connected in the middle of the exhaust flow path 5, and the downstream end of the recirculation flow path 6 is connected in the middle of the intake flow path 4. In the middle of the recirculation flow path 6, a flow rate adjustment valve 7 in which the actuator that is the subject of the present invention is incorporated is provided so that the amount of exhaust gas sent from the exhaust flow path 5 to the intake flow path 4 can be adjusted. Yes.
[0004]
Conventionally, for example, a structure described in Japanese Patent Publication No. 3-3066 is known as the flow rate adjusting valve 7. As shown in FIG. 5, the flow rate adjusting valve described in this publication has a flow hole 8 that can be connected in series in the middle of the recirculation flow path 6. The valve body 9 can freely open and close the circulation hole 8 and adjust the opening degree. One end of the rod 10 (upper end in FIG. 5) is coupled to the valve body 9, and an open piston 11 fixed to the other end (lower end in FIG. 5) of the rod 10 is fitted into the open cylinder 12 in an airtight manner. doing. Further, a closing spring 14 is provided between the cover piece 13 that closes the upper end opening of the opening cylinder 12 and the opening piston 11, and the flow hole 8 is closed to the valve body 9 via the rod 10. Gives direction elasticity. Further, a pressure chamber 15 is provided at the end of the open cylinder 12 on the opposite side of the open piston 11 from the close spring 14.
[0005]
Then, compressed air, which is a pressure fluid, can be freely fed into the pressure chamber 15 from a compressed air source 16 such as a compressor shown in FIG. An electromagnetic valve 17 is provided in the middle of the supply path 18 so that compressed air can be supplied to and discharged from the pressure chamber 15 through the supply path 18.
[0006]
The electromagnetic valve 17 is controlled by a controller 19 such as a microcomputer, and can switch the following states (1) to (3) at high speed.
(1) A state in which the compressed air source 16 and the pressure chamber 15 are communicated with each other.
(2) A state in which the pressure chamber 15 communicates with an exhaust port (not shown) provided in a part of the electromagnetic valve 17.
(3) A state in which the pressure chamber 15 is not communicated with either the compressed air source 16 or the exhaust port, and supply / exhaust of compressed air into the pressure chamber 15 is stopped.
[0007]
In order to reduce the amount of nitrogen oxides generated in the combustion chamber above the cylinder 1, when a part of the exhaust gas is sent into the combustion chamber, the solenoid valve 17 is switched to the state (1). As a result, compressed air is sent into the pressure chamber 15 of the flow rate adjusting valve 7, and the valve body 9 and the rod 10 are displaced against the elasticity of the closing spring 14 to open the flow hole 8. or, ExhaustIn order not to send the gas into the combustion chamber, the solenoid valve 17 is switched to the state (2). In this state, the pressure chamber 15 is opened to the atmosphere through an exhaust port provided in the supply passage 18 and the electromagnetic valve 17, and the valve body 9 and the rod 10 are displaced by the elasticity of the closing spring 14, thereby The hole 8 is closed. Further, when the opening degree of the flow hole 8 by the valve body 9 is fixed, the state is switched to the state (3). In this state, the pressure of the compressed air confined in the pressure chamber 15 and the elasticity of the closing spring 14 balance, and the valve body 9 and the rod 10 are not displaced. In order to realize such a state (3), a displacement meter 20 such as a potentiometer is provided at the end of the rod 10 protruding from the open cylinder 12, and the valve element 9 is provided. The position of can be detected freely.
[0008]
On the other hand, the controller 19 switches the state of the electromagnetic valve 17 in accordance with the following signals (a) to (c).
(A) Signal indicating accelerator opening
In order to obtain this signal, for example, a displacement sensor is provided in the middle of the cable 23 for transmitting the movement of the accelerator pedal 21 to the fuel injection pump 22.66This displacement sensor6 6Is input to the controller 19.
(B) Signal indicating engine speed
In order to obtain this signal, the rotation speed of the engine is detected by the rotation sensor 24, and the detection signal of the rotation sensor 24 is input to the controller 19.
(C) Signal indicating cooling water temperature
In order to obtain this signal, a temperature sensor 25 is provided in the water jacket portion of the engine, and a detection signal from the temperature sensor 25 is input to the controller 19.
[0009]
Among the signals (a) to (c), the signals (b) and (c) are necessary to know whether or not nitrogen oxides are likely to be generated in the cylinder 1, but (a) The signal of,When the accelerator pedal 21 is depressed hard for speed, climbing, etc.In addition,The amount of exhaust gas returned to the intake flow path 4 through the recirculation flow path 6 is reduced (including zero).It is necessary to make it.
[0010]
The exhaust gas recirculation device is configured as described above.AndThe amount of exhaust gas mixed into the air-fuel mixture is adjusted according to the vehicle operating conditions. This adjustment is performed by changing the amount of displacement of the rod 10 for driving the valve body 9. In the case of the conventional structure shown in FIGS. 4 to 5, the pressure in the pressure chamber 15 is adjusted by switching the electromagnetic valve 17 at high speed, and the displacement amount determined by the balance between the pressure and the closing spring 14 is It is detected by the displacement meter 20.
[0011]
However, in order to adjust the amount of displacement of the rod 10 in this way, an electromagnetic valve 17 that switches at high speed and a controller 19 that performs arithmetic processing at high speed are required. These are expensive although they are in practical use. Therefore, in order to reduce the cost of the exhaust gas recirculation device, it is desired to realize a structure that can perform sufficient adjustment even when using an electromagnetic valve or a controller whose operating speed and arithmetic processing speed are not so high.
[0012]
Conventionally, as a structure that can be applied to make it possible to adjust the displacement of the rod in multiple stages even when using a solenoid valve or controller whose operating speed or processing speed is not so fast, the following (1) (2) The structure described in is known.
(1) "New edition hydraulic and pneumatic handbook" issued by Ohm Co., Ltd. on February 25, 1989
On page 546 of this document, three cylinders with different strokes are arranged in series with each other, and the amount of displacement of one output rod is reduced to zero stroke by switching the pressure oil supply / discharge state to each cylinder. An actuator that can be switched in four stages including is described.
(2) JP-A-3-129109
In this publication, a cylinder, a first piston fitted into the cylinder by a first predetermined length so as to be displaceable, and a second predetermined length with respect to the first piston are made displaceable by a second predetermined length. An actuator with a second piston fitted in is described. The actuator includes a first hydraulic chamber that exists between the inner end surface of the cylinder and the end surface of the first piston, and a second hydraulic chamber that exists between the first and second pistons. Prepare. And the said 2nd piston is pressed toward the said 1st piston with the spring. In the case of this actuator, the stroke of the output rod with its base end coupled to the second piston, including zero, is switched by switching the pressure oil supply / discharge state to both the first and second hydraulic chambers. It can be controlled in 4 stages.
[0013]
However, in the case of the actuators described in (1) and (2), since at least two pistons are arranged in series in the axial direction, the dimension in the axial direction becomes large. In the case of an actuator for adjusting the opening degree of the valve body 9 of the exhaust gas recirculation device, the installation space is limited, and it is not preferable that the axial dimension is increased in order to enable multistage adjustment. . In view of such circumstances, the present inventor previously invented an actuator capable of adjusting the stroke of the rod in multiple stages without increasing the axial dimension (Japanese Patent Application No. 5-74572).
[0014]
[Description of the invention]
For example, the actuator according to the present invention is configured as shown in FIG. A cylinder hole 30 is provided inside a cylinder case 29 fixed to the lower surface of a block 28 provided with a flow hole 8 for flowing exhaust gas from the exhaust flow path 5 to the intake flow path 4 (see FIG. 4). A cylindrical outer piston 31 is provided inside the cylinder hole 30 in the axial direction.₃₁It is displaceable and airtightly fitted by the amount. A disc-shaped end plate 32 is fitted and fixed to the lower end portion of the outer piston 31 in an airtight manner. A bolt 34 is screwed onto the bottom plate portion 33 of the cylinder case 29 to prevent the lower end edge of the outer piston 31 from coming into contact with the upper surface of the bottom plate portion 33. A first port 35 is provided at the lower end of the cylinder case 29 so that compressed air can be supplied to and discharged from a portion 36 between the outer piston 31 and the bottom plate 33.
[0015]
An inner piston 37 is placed inside the outer piston 31 in the axial direction with respect to the outer piston 31.₃₇The displacement is freely and airtightly fitted by that amount. A protrusion 38 is formed at the center of the lower surface of the inner piston 37 to prevent the lower surface that is one end surface in the axial direction of the inner piston 37 and the upper surface that is one surface of the end plate 32 from contacting each other. An inner pressure chamber 39 is provided between these two surfaces. A second port 40 for supplying and discharging pressure fluid to and from the inner pressure chamber 39 is provided on the lower side surface of the cylinder case 29. The second port 40 and the inner pressure chamber 39 are communicated with each other through a supply / discharge passage. The supply / discharge passage includes through holes 41 and 41 for communicating the inner peripheral surface and the outer peripheral surface of the outer piston 31 and a recess 42 formed on the outer peripheral surface of the outer piston 31 over the entire periphery. Consists of. A rod 10 having a valve body 9 fixed at its end for opening and closing the end opening of the flow hole 8 is brought into contact with the upper surface of the inner piston 37 based on the elasticity of the closing spring 14. Further, the space 43 existing above the outer and inner pistons 31 and 37 communicates with the atmosphere through the filter 44.
[0016]
The actuator according to the prior invention configured as described above switches the supply state of the compressed air to the first and second ports 35 and 40 as shown in the following table, thereby reducing the stroke of the rod 10 (zero). 4 levels).
[0017]
[Table 1]

[0018]
That is, in a state where the supply of compressed air to any of the ports 35 and 40 is stopped, no upward force is applied to both the outer and inner pistons 31 and 37. Therefore, the rod 10 is lowered by the elasticity of the closing spring 14 and the valve body 9 completely closes the flow hole 8. Next, when the compressed air is supplied to the first port 35 and the supply of the compressed air to the second port 40 is stopped, the protrusion 38 on the lower surface of the inner piston 37 and the upper surface of the end plate 32 are brought into contact with each other. The outer piston 31 is in the L₃₁Ascend by minutes. As a result, the valve body 9 moves from the opening edge of the flow hole 8 to the L₃₁Leave for minutes. Next, in a state where the compressed air to the first port 35 is stopped and compressed air is supplied to the second port 40, the lower surface of the end plate 32 and the upper end surface of the bolt 34 are kept in contact with each other. The inner piston 37 is L₃₇Ascend by minutes. As a result, the valve body 9 moves from the opening edge of the flow hole 8 to the L₃₇Leave for minutes. Further, when the compressed air is supplied to the first and second ports 35 and 40, the outer piston 31 is L₃₁The inner piston 37 is not only lifted by the amount of₃₇Ascend by minutes. As a result, the valve body 9 moves from the opening edge of the flow hole 8 to the L₃₁+ L₃₇Leave for minutes.
[0019]
In the case of the actuator according to the present invention configured and operated in this way, the outer piston 31 and the inner piston 37 are arranged so as to overlap each other in the diameter direction, so that the stroke can be increased without increasing the dimension in the axial direction. Can be adjusted in multiple stages. If a second inner piston is provided further inside the inner piston 37, and the second inner piston is also displaceable separately from the outer piston and the inner piston, the stroke can be adjusted in eight stages. A specific structure for this purpose is also described in the Japanese Utility Model Application No. 5-74572.
[0020]
[Problems to be solved by the invention]
In the case of the actuator according to the present invention configured and operated as described above, if the cylinder case 29 is made of an aluminum alloy for weight reduction, the displacement L of the outer piston 31 is reduced.₃₁Differ greatly between low temperature and high temperature. That is, in the case of an actuator that is used in a state of being incorporated in the exhaust gas circulation device, the temperature becomes considerably high as the engine continues to operate. Accordingly, the temperatures of the cylinder case 29 and the outer piston 31 also become considerably high, and the thermal expansion amounts of both the members 29 and 31 become so large that they cannot be ignored. When these members 29 and 31 are made of the same material, the displacement L₃₁Is realWhenIt does not fluctuate greatly.
[0021]
On the other hand, when the cylinder case 29 having a large volume is made of an aluminum alloy and the outer piston 31 requiring strength is made of iron for weight reduction, the displacement L₃₁FluctuationsIs bigI'm angry. Specifically, the amount of thermal expansion of the cylinder case 29 made of aluminum alloy is larger than the amount of thermal expansion of the outer piston 31 made of iron.₃₁Will become bigger. As a result, when compressed air is supplied to the first port 35 and the outer piston 31 is lifted, the valve body 9 is unnecessarily separated from the opening edge of the flow hole 8, and exhaust gas more than desired is sucked through the flow hole 8. It will recirculate | reflux to the flow path 4 (FIG. 4). In view of such circumstances, the actuator capable of multi-stage positioning according to the present invention has a change in stroke accompanying a temperature change even when the cylinder case is made of an aluminum alloy for weight reduction.The smallIt was invented to suppress it.
[0022]
[Means for Solving the Problems]
The actuator capable of multistage positioning according to the present invention includes a cylinder case, a cylinder hole provided inside the cylinder case, and a cylinder hole provided inside the cylinder hole, like the actuator capable of multistage positioning according to the previous invention. Cylindrical, fitted in a freely displaceable manner in the axial directionAxial directionAn outer piston whose one end opening is closed by an end plate, and the cylinder caseOne axial endOf the cylinder holeOne axial endOf the outer pistonAxial directionA first port capable of supplying and discharging pressure fluid to a portion facing one end side, an inner piston fitted inside the outer piston so as to be freely movable in the axial direction with respect to the outer piston, and the inner piston An inner pressure chamber provided between one end surface in the axial direction and one surface of the end plate; and a second port provided in a part of the cylinder case for supplying and discharging pressure fluid to and from the inner pressure chamber; It includes a through hole that communicates the inner circumferential surface and the outer circumferential surface of the outer piston, and includes a supply / discharge passage that communicates the inner pressure chamber and the second port.
[0023]
Furthermore, the actuator capable of multi-stage positioning according to the present invention includes the outer piston.A locking bracket fixed to the other end in the axial direction, and an annular main portion having an inner diameter smaller than the inner diameter of the outer piston and an outer diameter larger than the outer diameter of the outer piston, constituting the locking bracket. And in the part near the outer diameter of this main part, Diametrically outward from the outer peripheral surface of this outer pistonEngagement protrusion composed of protruding partsAnd the cylinder holeOther axial endThe inner peripheral surface is formed in a state of projecting outward in the diameter direction from the inner peripheral surface of the cylinder hole, and the engagement protrusion is made to enter inside thereof.And an inner diameter larger than the outer diameter of the engaging protrusion and an axial dimension larger than the axial dimension of the engaging protrusion.An engaging recess. AndThe other end surface in the axial direction of the inner piston is allowed to abut the end surface of the rod loosely inserted through the inner diameter side of the main portion of the locking bracket,The outer piston can be displaced in the axial direction by an amount corresponding to the difference between the axial dimension of the engaging recess and the axial dimension of the engaging protrusion.It is said. In addition, the inner piston is the inner dimension of the inner piston, the axial dimension of the inner piston, and a portion projecting in a diametrical direction from the inner peripheral surface of the outer piston at a portion closer to the inner diameter of the end plate and the main portion. It is displaceable in the axial direction by an amount corresponding to the difference between.
[0024]
[Action]
For example, the operation of adjusting the stroke of the rod for driving the valve body in multiple stages by the actuator capable of multi-stage positioning of the present invention configured as described above is the same as in the case of the above-described prior invention. . In particular, in the case of the actuator capable of multistage positioning according to the present invention, the displacement amount of the outer piston is regulated by the difference between the axial dimension of the engaging recess and the axial dimension of the engaging protrusion. Stroke change based on ascentThe smallIt can be suppressed. That is, since the absolute value of the axial dimension of the engaging recess is much smaller than the axial dimension of the cylinder case, even if the cylinder case is made of an aluminum alloy and the temperature of the cylinder case rises, The amount of increase in the axial dimension of the engaging recess is small. Therefore, the variation of the displacement amount of the outer piston with temperature changeThe smallI can do it.
[0025]
【Example】
The embodiment of the present invention will be described with reference to the drawings, but the vertical and horizontal expressions regarding the position and direction are for convenience of explanation, and the actual installation state may be 90 degrees different from the state described in the drawings and embodiments. Good or upside down. 1 to 3 show an embodiment of the present invention. On the upper inner side of the valve case 45 made of a metal such as aluminum or cast iron, there is provided a flow hole 8 that opens to the upper end surface of the valve case 45 and the upper one side surface (left side surface in FIG. 1). When the exhaust gas recirculation device is configured, the upper opening which is the upstream end of the circulation hole 8 communicates with the exhaust flow path 5 (FIG. 4), and the side opening which is the downstream end communicates with the intake flow path 4 (FIG. 4). And connected in series to the recirculation flow path 6 (FIGS. 4 to 5).
[0026]
A valve body 9 for opening and closing the flow hole 8 and adjusting the opening degree is provided at the upper end opening of the flow hole 8. The upper end of the rod 10 is coupled to the center of the lower surface of the valve body 9. In the illustrated embodiment, a mushroom valve in which the valve body 9 and the rod 10 are integrated is used. The rod 10 is slidably inserted into a through hole 46 formed in the valve case 45 extending in the vertical direction. A spring seat 49 is fixed to a portion of the lower end portion of the rod 10 that protrudes downward from the through hole 46. The spring seat 49 is formed of a synthetic resin, metal or the like in an annular shape as a whole, and has a tapered hole that becomes smaller as the inner diameter increases in the center. Further, a concave groove 47 is formed over the entire circumference in a portion located on the inner side of the tapered hole on the outer peripheral surface of the lower end portion of the rod 10. Then, the ridge formed on the inner peripheral surface of the cotter 48 which is made into a two-divided tapered cylindrical shape with synthetic resin or metal and fitted inside the tapered hole is engaged with the concave groove 47. Yes. Therefore, the spring seat 49 is not displaced downward with respect to the rod 10.
[0027]
Between the spring seat 49 supported at the lower end of the rod 10 as described above and the lower surface of the partition wall 50 formed inside the valve case 45, the closing spring 14 which is a compression coil spring is provided. The closing spring 14 elastically pushes the rod 10 downward through the spring seat 49 to give the valve body 9 elasticity in a direction to close the flow hole 8. The through hole 46 is provided so as to penetrate the partition wall 50 up and down.
[0028]
Further, a seal ring 51 made of heat-resistant rubber or the like is fitted on the intermediate portion of the rod 10 immediately below the lower end opening of the through hole 46 so that the inner peripheral surface of the through hole 46 and the rod 10 are The exhaust is prevented from leaking through the gap between the outer peripheral surface. Further, a cylindrical portion 52 is formed at the center of the lower surface of the partition wall 50, and the upper half of the holding cylinder 53 formed in a cylindrical shape by synthetic resin or metal is fitted on the lower end portion of the cylindrical portion 52. It is fixed. The seal ring 51 is prevented from falling off by an inward flange-shaped flange 54 formed at the lower end of the holding cylinder 53. The inner peripheral surface of the upper half part of the holding cylinder 53 and the outer peripheral surface of the lower half part of the cylindrical part 52 are joined together by bonding or uneven engagement (not shown) to prevent the holding cylinder 53 from coming off from the cylindrical part 52. I am trying.
[0029]
In addition, a cooling jacket 55 is provided inside the partition wall 50, and the engine cooling water can flow through the cooling jacket 55 through a water supply port 56 and a drain port 57. The cooling jacket 55 has a function of suppressing a temperature increase in the lower half of the rod 10. That is, during operation of the engine, the exhaust flowing through the exhaust flow path 5 (FIG. 4) is transmitted to the upper end surface of the valve body 9, or the exhaust valve flowing from the exhaust flow path 5 and the flow hole 8 is used for the valve. The heat transmitted to the body 9 and the rod 10 raises the temperature of the upper portion of the rod 10. However, most of the heat transferred from the exhaust to the rod 10 is carried away by the cooling water flowing through the cooling jacket 55. Therefore, even if the temperature of the upper half of the rod 10 rises, the temperature rise of the portion where the seal ring 51 is attached is limited at the lower portion of the intermediate portion of the rod 10. As a result, the durability of the seal ring 51 can be sufficiently ensured.
[0030]
A cylinder case 29a is coupled and fixed to the lower surface of the valve case 45. A cylinder hole 30a is provided inside the cylinder case 29a. Inside the cylinder hole 30a, a bottomed cylindrical outer piston 31a is fitted so as to be displaceable in an axial direction and in an airtight manner. The lower end of the outer piston 31a is hermetically closed by an end plate 32a formed integrally with the outer piston 31a. Further, a concave portion 58 extending in the diameter direction is formed on the lower surface of the end plate 32a, and the lower end surface of the outer piston 31a is formed.WhenAbove the bottom plate portion 33a of the cylinder case 29aThere is an axial clearance between the two surfaces, and these surfacesPrevent contact. And the 1st port 35a is provided in the center part of the said baseplate part 33a, and compressed air can be freely supplied and discharged below the said outside piston 31a.
[0031]
An inner piston 37a is disposed inside the outer piston 31a in the axial direction with respect to the outer piston 31a._37a  The displacement is freely and airtightly fitted by that amount. A cylindrical portion 59 is formed on the lower surface of the inner piston 37a, and a lower surface that is one axial end surface of the inner piston 37a and an upper surface that is one surface of the end plate 32a.An axial clearance is provided between the two surfaces, and these surfaces contact each other even when the valve body 9 is closed.To preventdoing. AndAn inner pressure chamber 39a is provided between these two surfaces. A second port 40a for supplying and discharging pressure fluid to and from the inner pressure chamber 39a is provided on the side surface of the intermediate portion of the cylinder case 29a. And this 2nd port 40a and the said inner side pressure chamber 39a are connected by the supply / discharge passage. This supply / discharge passage isA concave portion 42b that is a ring-shaped passage formed over the entire circumference on the inner circumferential surface of the cylinder hole 30a;A through hole 41a communicating the inner peripheral surface and the outer peripheral surface of the outer piston 31a;,A recess 42a is formed on the outer peripheral surface of the inner piston 37a over the entire circumference, and a through hole 41b is provided for communicating the inner peripheral surface and the outer peripheral surface of the cylindrical portion 59. A rod 10 having a valve body 9 fixed at its end for opening and closing the end opening of the flow hole 8 is brought into contact with the upper surface of the inner piston 37 a based on the elasticity of the closing spring 14. Further, the space 43a existing above the outer and inner pistons 31a and 37a communicates with the atmosphere through a filter (not shown).
[0032]
Further, a locking bracket 60 is screwed and fixed to the outer peripheral surface of the upper end portion of the outer piston 31a. The locking bracket 60 has a cylindrical portion 62 formed on the lower surface of an annular main portion 61. And the internal thread formed in the internal peripheral surface of this cylindrical part 62 and the external thread formed in the upper end part outer peripheral surface of the said outer side piston 31a are screwed together, It is fixing to the upper end part of the said outer side piston 31a. In this state, the outer half portion in the diameter direction of the main portion 61 constitutes an outward flange-like engagement protrusion 63 that protrudes outward in the diameter direction from the outer peripheral surface of the outer piston 31a.The lower end portion of the rod 10 is loosely inserted through the inner diameter side of the main portion 61, and the lower end surface is abutted against the upper end surface of the inner piston 37a.
[0033]
On the other hand, an engagement recess 64 is formed on the inner peripheral surface of the upper end portion of the cylinder hole 30a so as to protrude outward in the diameter direction from the inner peripheral surface of the cylinder hole 30a. That is, the engagement recess 64 is formed between the step 65 formed on the outer periphery of the upper end opening of the cylinder case 29 a and the lower surface of the valve case 45. The engagement protrusion 63 is inserted inside the engagement recess 64. Thickness dimension T extending in the axial direction of the engaging recess 64₆₄Is a thickness dimension T extending in the axial direction of the engaging protrusion 63.₆₃Larger than (T₆₄> T₆₃). Therefore, the outer piston 31a has a thickness dimension T of the engaging recess 64.₆₄And the thickness dimension T of the engaging protrusion 63₆₃Difference from (T₆₄-T₆₃) Is displaceable in the axial direction by the amount corresponding to. In other words, the displacement L of the outer piston 31a_31a  Is the difference in thickness (T₆₄-T₆₃) Minutes.
[0034]
The actuator according to the present invention configured as described above changes the stroke of the rod 10 by switching the supply state of compressed air to the first and second ports 35a, 40a as shown in Table 1 above. It can be adjusted in 4 steps (including zero). That is, in a state where the supply of compressed air to both the first and second ports 35a and 40a is stopped, no upward force is applied to both the outer and inner pistons 31a and 37a. Therefore, the rod 10 is lowered by the elasticity of the closing spring 14 and the valve body 9 completely closes the flow hole 8. Next, when the compressed air is supplied to the first port 35a and the supply of the compressed air to the second port 40a is stopped, the lower end edge of the cylindrical portion 59 on the lower surface of the inner piston 37a and the upper surface of the end plate 32a are connected. The outer piston 31a remains in the L_31a  Ascend by minutes. As a result, the valve body 9 moves from the opening edge of the flow hole 8 to the L_31a  Leave for minutes.
[0035]
Next, in a state where the compressed air to the first port 35a is stopped and the compressed air is supplied to the second port 40a,The step portion 65 and the lower surface of the engaging projection 63;The inner piston 37a is in an L_37a  Ascend by minutes. As a result, the valve body 9 moves from the opening edge of the flow hole 8 to the L_37a  Leave for minutes.
[0036]
Further, in a state where compressed air is supplied to the first and second ports 35a, 40a, the outer piston 31a is L_31a  The inner piston 37a is not only lifted by a minute amount but also the outer piston 31a_37a  Ascend by minutes. As a result, the valve body 9 moves from the opening edge of the flow hole 8 to the L_31a  + L_37a  Leave for minutes.
[0037]
As described above, the action of changing the stroke of the rod 10 for driving the valve body 9 in four stages is the same as in the case of the above-described prior invention. In particular, in the case of an actuator capable of multistage positioning according to the present invention, the displacement amount L of the outer piston 31a._31a  The thickness dimension T of the engaging recess 64₆₄And the thickness dimension T of the engaging protrusion 63₆₃Difference from (T₆₄-T₆₃), The stroke changes based on the temperature rise.The smallIt can be suppressed. That is, the thickness T of the engaging recess 64₆₄Is much smaller than the axial dimension of the cylinder case 29a. Therefore, even when the cylinder case 29a is made of an aluminum alloy and the temperature of the cylinder case 29a rises, the thickness dimension T of the engaging recess 64 is increased.₆₄The amount of increase is small. Therefore, the displacement amount L of the outer piston 31a accompanying the temperature change._31a  FluctuationsThe smallI can do it.
[0038]
【The invention's effect】
Since the actuator capable of multi-stage positioning of the present invention is configured and operates as described above, in addition to the effect of the previous invention, the dimension in the axial direction can be reduced and the stroke can be changed in multiple stages. Even when the cylinder case is made of aluminum alloy to reduce weight, the stroke changes with temperature changes.The smallIt can be suppressed. Therefore, the exhaust gas recirculation device can be configured without using particularly expensive components, and the performance of the exhaust gas recirculation device can be stabilized regardless of temperature changes.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a view as seen from below in FIG.
3 is an enlarged view of the lower part of FIG.
FIG. 4 is a circuit diagram of an exhaust gas recirculation device.
FIG. 5 is a cross-sectional view of a conventional flow rate adjustment valve.
FIG. 6 is a cross-sectional view of a flow rate adjusting valve incorporating an actuator capable of multistage positioning according to the previous invention.
[Explanation of symbols]
1 cylinder
2 Intake valve
3 Exhaust valve
4 Intake channel
5 Exhaust flow path
6 Recirculation flow path
7 Flow control valve
8 distribution hole
9 Disc
10 Rod
11 Open piston
12 Open cylinder
13 Lid
14 Closing spring
15 Pressure chamber
16 Compressed air source
17 Solenoid valve
18 Supply path
19 Controller
20 Displacement meter
21 Accelerator pedal
22 Fuel injection pump
23 Cable
24 Rotation sensor
25 Temperature sensor
28 blocks
29, 29a Cylinder case
30, 30a Cylinder hole
31, 31a Outer piston
32, 32a end plate
33, 33a Bottom plate part
34 volts
35, 35a First port
36, 36a part
37, 37a Inner piston
38 Projections
39, 39a Inner pressure chamber
40, 40a Second port
41, 41a, 41b Through hole
42, 42a42b  Recess
42b + 41a + 42a + 41b Supply / discharge passage
43, 43a space
44 filters
45 Valve case
46 Through hole
47 Groove
48 cotters
49 Spring seat
50 Bulkhead
51 Seal ring
52 Cylindrical part
53 Retaining cylinder
54 Buttocks
55 Cooling jacket
56 Water inlet
57 Drainage port
58 recess
59 Cylindrical part
60 Locking bracket
61 Main part
62 Cylindrical part
63 engaging protrusion
64 engagement recess
65 steps
66 Displacement sensor

Claims (1)

A cylinder case, a cylinder hole provided on the inner side of the cylinder case, and a cylindrical one end opening in the axial direction that is slidably fitted to the inner side of the cylinder hole with an end plate. A first outer cylinder that is provided at a first axial end of the cylinder case, and that can be supplied and discharged with pressure fluid to a portion of the first axial end of the cylinder hole facing the first axial end of the outer piston. A port, an inner piston fitted inside the outer piston so as to be freely displaceable in the axial direction relative to the outer piston, and provided between one axial end surface of the inner piston and one surface of the end plate. An inner pressure chamber, a second port provided in a part of the cylinder case for supplying and discharging pressure fluid to and from the inner pressure chamber, and a through hole communicating with the inner peripheral surface and the outer peripheral surface of the outer piston. Comprise configured to constitute a supply and discharge passage for communicating the said inner pressure chamber and the second port, and a locking bracket which is fixed to the other axial end portion of the outer piston, the locking bracket, this An annular main portion having an inner diameter smaller than the inner diameter of the outer piston and an outer diameter larger than the outer diameter of the outer piston, and a portion closer to the outer diameter of the main piston, the outer diameter of the outer piston is more diametrically outward. the engaging projections constituted by the protruding portion toward the axial direction other end portion inner peripheral surface of the cylinder bore, are formed in a state protruding diametrically outward from the inner peripheral surface of the cylinder bore, An engagement recess having an inner diameter larger than the outer diameter of the engagement protrusion and an axial dimension larger than the axial dimension of the engagement protrusion, the inside of which the engagement protrusion is inserted , On the other axial end surface of the inner piston, Has freely abutting the end surface of the loosely inserted rods the inner diameter side of the main portion of the stopper bracket, the outer piston, corresponds to the difference between the axial dimension of the axial dimension and the engagement projection of the engaging recess The inner piston is displaceable in the axial direction as much as the inner piston, and the inner piston is positioned inside the outer piston. An actuator capable of multi-stage positioning that is displaceable in the axial direction by an amount corresponding to the difference from the portion protruding in the diametrical direction from the inner peripheral surface .

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