JP3609012B2

JP3609012B2 - Hydraulic actuator system

Info

Publication number: JP3609012B2
Application number: JP2000244774A
Authority: JP
Inventors: 和人藤山; 一雄肥田; 博志吉川; 義和瓜本
Original assignee: Kawasaki Precision Machinery KK
Current assignee: Kawasaki Precision Machinery KK
Priority date: 2000-08-11
Filing date: 2000-08-11
Publication date: 2005-01-12
Anticipated expiration: 2020-08-11
Also published as: JP2002054609A

Description

【０００１】
【発明の属する技術分野】
本発明は、油圧アクチュエータによって動作する油圧機器の被動作部の動作を制御するとともに、この被動作部を重力に抗して停止させることができる油圧アクチュエータシステムに関し、さらに詳しくは、たとえば油圧ショベルのアームやブームを、停止状態において自重で動作しないように確実に停止させる油圧アクチュエータシステムに関する。
【０００２】
【従来の技術】
図４は、参考例の油圧アクチュエータシステム１を示す図である。油圧ショベルのアームやブームなどの被動作部２の動作は、この被動作部２の駆動源である油圧シリンダ５への圧油の流れ方向を切換弁３で切換えることによって制御される。また、この被動作部２を停止させるときには、油圧シリンダ５への圧油の給排を切換弁３で停止する。この被動作部２の停止状態において、被動作部２はその自重によって油圧シリンダ５のピストンロッド１１を押し下げる方向に押圧する。したがって、この押圧力によって、油圧シリンダ５と切換弁３との間の油流路１２に保持されている圧油は、切換弁３のスプール孔１０とスプール９との間の僅かな間隙から漏れ出して圧油タンク１７に戻るおそれがあるため、この従来技術の油圧アクチュエータシステム１では、油圧シリンダ５と切換弁３とを接続する油流路１２とシリンダ側ポート１６との間にロック弁４を介在させ、被動作部２を停止させるときには、このロック弁４を閉じて、油流路１２とシリンダ側ポート１６との間の圧油の移動を阻止する。したがって被動作部２の自重によって、油圧シリンダ５および油流路１２内の圧油が、切換弁３側に戻ることが確実に防止され、被動作部２の停止時に、この被動作部２が自重によって動くことが防がれる。
【０００３】
【発明が解決しようとする課題】
上記ロック弁４は、挿通孔８が形成されたハウジング７と、この挿通孔８内に摺動自在に装着される弁体１３とによって構成される。この弁体１３が弁座１４に着座することによって、油流路１２とシリンダ側ポート１６との間で圧油の移動が阻止されて被動作部２が停止し、弁体１３が弁座１４から離反することによって、油流路１２とシリンダ側ポート１６との間で圧油が移動可能になり、被動作部２の動作が可能となる。この油圧アクチュエータシステム１では、被動作部２の停止時に被動作部２の自重によって、油圧シリンダ５、油圧流路１２および圧油室１５内の圧油の圧力が上昇し、たとえば７０〜３５０ｋｇ／ｃｍ^２程度にまで上昇する。したがって、弁体１３が弁座１４から離反したとき、この油圧シリンダ５、油流路１２および圧油室１５内の高圧力の圧油が切換弁３側に急に流れ、これによって瞬間的な圧力降下が生じ、このときの衝撃が油流路内を伝わって、たとえば「ゴツン」という衝撃音が発生する。したがって、油圧ショベルのオペレータが、ゆっくり操作しているにも拘わらず衝撃音がするため、油圧ショベルが故障するのではないかと心配する。
【０００４】
したがって本発明の目的は、被動作部の停止状態を解除したとき、衝撃音が発生することを防止することができる油圧アクチュエータシステムを提供することである。
【０００５】
【課題を解決するための手段】
本発明は、油圧アクチュエータへの圧油の給排の動作位置および停止位置を切換える第１切換弁５３と、油圧アクチュエータおよび切換弁を接続する油流路に介在され、油流路を開放および遮断するロック弁５４とを有し、
油圧アクチュエータによって動作する油圧機器の被動作部を重力に抗して停止させるとき、第１切換弁５３を停止位置に切換えるとともに、ロック弁５４を閉じて油流路を遮断し、
被動作部を動作させるとき、第１切換弁５３を動作位置に切換えるとともに、ロック弁を開いて油流路を開放する油圧アクチュエータシステムにおいて、
前記ロック弁は、
（ａ）ハウジング５７であって、このハウジング５７には、
軸線７３を有する挿通孔７４と、
挿通孔７４の前記軸線７３と同一直線上に軸線を有し、円筒状である弁孔８１が形成される弁座６４と、
挿通孔７４の一端部と弁座６４との間に設けられ、油圧アクチュエータに接続される第１油圧室７６と、
挿通孔７４に関して第１油圧室７６とは反対側に設けられる第２油圧室７７とが、形成されるハウジング５７と、
（ｂ）弁体６３であって、
挿通孔７４に前記軸線７３と同軸に嵌装され、前記軸線７３に沿って摺動可能であり、一端部が第１油圧室７６に臨み、他端部が第２油圧室７７に臨む円柱状の基部８２と、
基部８２の前記一端部に連なり、第１油圧室７６内に配置され、弁座６４に着座するシート面９１を有する算盤玉状の着座部８３と、
着座部８３の基部８２とは反対側の端部に連なり、弁孔８１に挿通され、弁孔８１との間に絞りとして機能する円環状の間隙９３を形成する円柱状の突部８４とを有する弁体６３と、
（ｃ）前記基部８２を弁座６４に向けて押圧するばね部材９５とを有し、
（ｄ）弁体６３のシート面９１が弁座６４に着座している状態における弁体６３の第１油圧室７６に臨む第１油圧室側受圧面は、第２油圧室７７に臨む第２油圧室側受圧面８９，９０よりも円環状の領域９７の面積差だけ小さく構成され、
第２切換弁７９が設けられ、この第２切換弁７９は、
第１および第２油圧室７６，７７を接続する第１位置と、
第１油圧室７６を遮断し、第２油圧室７７をタンク６７に接続する第２位置とを、切換え可能に有し、
前記被動作部の停止状態を解除するとき、前記第１切換弁５３を動作位置に切換えるとともに、第２切換弁７９を第１位置から第２位置に切換えて、前記弁体を前記弁座から離反する方向に移動させ、弁座と突部との間の間隙を介して圧油を給排することを特徴とする油圧アクチュエータシステムである。
【０００６】
本発明に従えば、油圧アクチュエータによって動作する油圧機器の被動作部を重力に抗して停止させるとき、第１切換弁を停止位置に切換えるとともに、第２切換弁７９を第１位置とし、油圧アクチュエータへの圧油の給排を停止する。ロック弁の弁体は、弁座に着座し、油圧アクチュエータと第１切換弁との間で圧油の移動が阻止される。したがって、油圧アクチュエータとロック弁との間の圧油が漏れることなく保持され、被動作部は重力に抗して確実に停止する。なお、弁体の先端部に設けられた円柱状の突部は、弁座の円筒状の弁孔内に挿通される。
【０００７】
被動作部を動作させるとき、第１切換弁を動作位置に切換えるとともに、第２切換弁７９を第２位置とし、油圧アクチュエータへの圧油の給排を可能な状態にする。弁座に着座している弁体は、弁座から離反する。したがって、被動作部の動作開始時には、油圧アクチュエータには、弁座と突部との間の僅かな間隙が円環状の絞りとして機能し、少量ずつ圧油が給排されることになる。つまり被動作部の停止時に、油圧アクチュエータと切換弁との間に保持されていた圧油は、僅かな間隙を通ってゆっくりと移動することになるので、瞬間的な圧力降下が防止され、これによって衝撃音の発生が阻止される。
【０００８】
【発明の実施の形態】
図１〜図３を参照して、本発明の油圧アクチュエータシステム５１について説明する。図１は、本発明の実施の一形態の油圧アクチュエータシステム５１の全体の構成を示す図であり、図２は図１の仮想線で囲まれる領域６８を拡大して示す図であり、図３は図２の切断面線ＩＩＩ−ＩＩＩから見た断面図である。油圧アクチュエータシステム５１は、油圧ショベルのアームやブームなどの被動作部５２を駆動する油圧アクチュエータである油圧シリンダ５５への圧油の給排および停止を制御する第１切換弁５３と、この第１切換弁５３と油圧シリンダ５５との間に介在されるロック弁５４とを含んで構成される。
【０００９】
第１切換弁５３は、３位置３ポート切換弁であって、ハウジング５７に形成されるスプール孔６０と、このスプール孔６０内に摺動自在に嵌装されるスプール５９とによって構成され、スプール５９はスプール孔６０の第１軸線７２に同軸に設けられる。このハウジング５７には、スプール孔６０に臨んで開口するポンプ側ポート７０と、シリンダ側ポート７５と、タンク側ポート７１とが、第１軸線７２に沿って、一方側（図１の左方）から他方側（図１の右方）に、この順番で形成される。このポンプ側ポート７０に油圧ポンプ６９が接続され、タンク側ポート７１に圧油タンク６７が接続される。
【００１０】
ロック弁５４は、弁体６３と、ハウジング５７に形成され、上記第１軸線７２に直交する第２軸線７３を有する挿通孔７４とを有し、弁体６３が挿通孔７４に同軸に、摺動自在に嵌装される。
【００１１】
上記挿通孔７４の第２軸線７３方向一方側（図１の下方）には、小径の短円筒状の弁孔８１が連なる。またハウジング５７には、上記挿通孔７４に臨んで開口する第１圧油室７６と第２圧油室７７とが、第２軸線７３に沿って一方側（図１の下方）から他方側（図１の上方）に、この順番で形成される。この第１圧油室７６と第２圧油室７７とが、図２に示す油流路７８および２位置３ポート切換弁７９（以下、第２切換弁７９と称する）を介して接続され、さらに第１圧油室７６は、油流路６６を介して油圧シリンダ５５のシリンダ室８０に接続される。なお、図１では第２切換弁７９は省略して示している。
【００１２】
上記第１圧油室７６の第２軸線７３方向一方側（図１の下方）の壁面に形成される段差が、弁座６４として機能する。すなわち、上記の挿通孔７４側に、弁孔８１が形成された弁座６４が設けられる。
【００１３】
図２に示すように、弁体６３は、第２軸線７３方向一方側端部に、一方側（図２の下方）になるに連れて先細となるテーパ面８５が形成された円柱状の基部８２と、この基部８２の一方側端部に連なる軸部８８と、この軸部８８の一方側端部に連なる算盤玉状の着座部８３と、この着座部８３の一方側端部に連なる円柱状の突部８４とによって構成される。
【００１４】
上記の弁体６３の基部８２は、挿通孔７４に、第２軸線７３に同軸に嵌装され、この第２軸線７３に沿って摺動可能である。この基部８２の凹所９６内には、ばね部材９５が装着され、このばね部材９５は基部８２を第２軸線７３方向一方側（図２の下方）に押圧する。なお上記第２圧油室７７は、基部８２の凹所９６内に臨んで開口する。また、基部８２のテーパ面８５側と、軸部８８と、着座部８３とは、第１圧油室７６内に配置される。また突部８４は、第２軸線７３と同軸に、かつ弁座６４と弁孔８１に臨むハウジング５７の壁面との間に円環状の僅かな間隙９３を開けた状態で、弁孔８１に挿通される。したがって弁孔８１は、前記軸線７３と同一直線上に軸線を有する。
【００１５】
図１に示すように、着座部８３の第２軸線７３方向下方側のシート面９１が、弁座６４に着座すると、第１切換弁５３のシリンダ側ポート７５と、ロック弁５４の第１圧油室７６との間で圧油の移動が阻止される。つまり、第１切換弁５３と油圧シリンダ５５とが遮断される。
【００１６】
上記弁体６３は、第１圧油室７６および第２圧油室７７内の圧油の圧力に基づいて、第２軸線７３に沿って摺動する。さらに詳しく述べると、第１圧油室７６内の圧油は基部８２の第２軸線７３方向下方側のテーパ面８５の円環状の領域９７に作用して、第１押圧力ｆ１で弁体６３を第２軸線７３方向他方側（図２の上方）に押圧する。第２圧油室７７内の圧油は、基部８２の真円状の第１受圧面８９と円環状の第２受圧面９０とに作用して、第２押圧力ｆ２で弁体６３を第２軸線７３方向一方側（図２の下方）に押圧する。つまり、上記の第１押圧力ｆ１と第２押圧力ｆ２との押圧力の差によって、弁体６３が第２軸線７３に沿って変位する。
【００１７】
つまり、第２切換弁７９が図２に示す第１位置にあるとき、第１圧油室７６と第２圧油室７７とが接続され、第１圧油室７６内の圧油が、第２圧油室７７に給送される。したがって、第１圧油室７６の圧力と第２圧油室７７の圧力とが等しくなるので、弁体６３のシート面９１が弁座６４に着座している状態における弁体６３の第１および第２油圧室７６，７７に臨む各受圧面の面積差によって、第２押圧力ｆ２が第１押圧力ｆ１よりも大きくなり、弁体６３は第２軸線７３方向一方側（図２の下方）に変位して、弁座６４に着座する。すなわち弁体６３のシート面９１が弁座６４に着座している状態における弁体６３の第１油圧室７６に臨む第１油圧室７６側受圧面は、第２油圧室７７に臨む第２油圧室７７側受圧面８９，９０よりも面積差９７だけ小さく構成される。このようにして、第１圧油室７６と第１切換弁５３とが遮断される。
【００１８】
また、第２切換弁７９が第２位置に切換えられると、第１圧油室７６と第２圧油室７７とが遮断され、第２圧油室７７と圧油タンク６７とが接続される。したがって、第２圧油室７７の圧力がタンク圧となるので、第１押圧力ｆ１が第２押圧力ｆ２よりも大きくなり、弁体６３は第２軸線７３方向他方側（図２の上方）に変位して、弁座６４から離反する。すると、第１圧油室７６とシリンダ側ポート７５とが、円環状の僅かな間隙９３を介して連通し、油圧シリンダ５５と第１切換弁５３との間で圧油の移動が可能となる。
【００１９】
次に、油圧アクチュエータシステム５１の動作について説明する。被動作部５２を重力に抗して停止させるとき、第１切換弁５３を停止位置に切換えるとともに、第２切換弁７９を第１位置に切換える。すると、ポンプ側ポート７０およびタンク側ポート７１と、シリンダ側ポート７５とが遮断される。さらに、第１圧油室７６と第２圧油室７７とが接続されるので、第１圧油室７６内の圧油が第２圧油室７７に送られる。したがって、第１圧油室７６と第２圧油室７７との圧力が等しくなり、第２押圧力ｆ２が第１押圧力ｆ１に打ち勝って、弁体６３は第２軸線７３方向一方側（図２の下方）に移動する。これによって、弁体６３の着座部８３のシート面８７が弁座６４に着座し、第１切換弁５３と油圧シリンダ５５との間で圧油の移動が阻止される。したがって、油圧シリンダ５５、第１圧油室７６および第２圧油室７７内の圧油が漏れることなく保持され、被動作部５２は、重力に抗して確実に停止する。なお、図１および図２は、この被動作部５２の停止状態を示している。
【００２０】
被動作部５２を動作させるとき、特に被動作部５２を上昇させるとき、第１切換弁５３を動作位置である給送位置に切換えるとともに、第２切換弁７９を第２位置に切換える。すると、ポンプ側ポート７０とシリンダ側ポート７５とが、スプール５９の小径部９２（図１参照）を介して接続され、シリンダ側ポート７５とタンク側ポート７１とが遮断される。さらに、第１圧油室７６と第２圧油室７７とが遮断され、第２圧油室７７が圧油タンク６７に接続される。すなわち、第２圧油室７７内の圧油が、圧油タンク６７に排出され、第１押圧力ｆ１が第２押圧力ｆ２に打ち勝って、弁体６３は第２軸線７３方向他方側（図２の上方）に移動する。これによって、第１圧油室７６とシリンダ側ポート７５とが、突部８４と弁孔８１との間の僅かな間隙９３を介して、圧油が移動可能に連通する。したがって、この僅かな間隙９３が絞りとして機能するので、油圧ポンプ６９から給送された圧油は、間隙９３、第１圧油室７６および油流路６６を介して、ゆっくりと少量ずつ油圧シリンダ８０に給送される。このようにして、被動作部５２を停止状態から上昇させたとき、急に圧油を給送することに起因する「ゴツン」という衝撃音の発生を防止できる。
【００２１】
被動作部５２を動作させるとき、特に被動作部５２を下降させるとき、第１切換弁５３を動作位置である排出位置に切換えるとともに、第２切換弁７９を第２位置に切換える。すると、タンク側ポート７１とシリンダ側ポート７５とが、スプール５９の小径部９２（図１参照）を介して接続され、シリンダ側ポート７５とポンプ側ポート７０とが遮断される。さらに、第１圧油室７６と第２圧油室７７とが遮断され、第２圧油室７７が圧油タンク６７に接続される。すなわち、第２圧油室７７内の圧油が圧油タンク６７に排出され、第１押圧力ｆ１が第２押圧力ｆ２に打ち勝って、弁体６３は第２軸線７３方向他方側（図２の上方）に移動する。これによって、第１圧油室７６とシリンダ側ポート７５とが、突部８４と弁孔８１との間の僅かな間隙９３を介して、圧油が移動可能に連通する。したがって、この僅かな間隙９３が絞りとして機能するので、油圧シリンダ８０から排出される圧油は、油流路６６、第１圧油室７６および間隙９３を介して、ゆっくりと少量ずつ圧油タンク６７に排出される。このようにして、被動作部５２を停止状態から下降させたとき、急に圧油が排出されることに起因する「ゴツン」という衝撃音の発生を防止できる。
【００２２】
上述したように、本発明の油圧アクチュエータシステム５１は、弁体６３の着座部８３に連なって円柱状の突部８４を形成するだけの簡単な構成で、衝撃音の発生を防止することができる。したがって、部品点数がほとんど増加することがなく、コストの増加も抑えて、衝撃音の発生を防止することができる。
【００２３】
【発明の効果】
本発明によれば、油圧アクチュエータによって動作する油圧機器の被動作部を重力に抗して停止させるとき、第１切換弁を停止位置に切換えるとともに、第２切換弁７９を第１位置とし、ロック弁の弁体を弁座に着座させて、油圧アクチュエータと第１切換弁との間で圧油の移動を阻止する。したがって、油圧アクチュエータとロック弁との間で圧油が漏れることなく保持され、被動作部は重力に抗して確実に停止する。被動作部を動作させるとき、第１切換弁を動作位置に切換えるとともに、第２切換弁７９を第２位置とし、ロック弁の弁座に着座している弁体を弁座から離反させる。すると、被動作部の動作開始時には、油圧アクチュエータには、弁座と突部との間の僅かな間隙を通過して、少量ずつ圧油が給排され、瞬間的な圧力降下が防止される。これによって衝撃音の発生が阻止される。
【図面の簡単な説明】
【図１】本発明の実施の一形態の油圧アクチュエータシステム５１の全体の構成を示す図である。
【図２】図１の仮想線で囲まれる領域６８を拡大して示す図である。
【図３】図２の切断面線ＩＩＩ−ＩＩＩから見た断面図である。
【図４】参考例の油圧アクチュエータシステム１を示す図である。
【符号の説明】
５１油圧アクチュエータシステム
５２被動作部
５３第１切換弁
５４ロック弁
５５油圧シリンダ
６３弁体
６４弁座
７４挿通孔
８１弁孔
８３突部
９３間隙[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic actuator system capable of controlling the operation of a driven part of a hydraulic device operated by a hydraulic actuator and stopping the driven part against gravity, and more specifically, for example, a hydraulic excavator The present invention relates to a hydraulic actuator system that reliably stops an arm or a boom so as not to operate with its own weight in a stopped state.
[0002]
[Prior art]
FIG. 4 is a diagram showing a hydraulic actuator system 1 of a reference example . The operation of the driven part 2 such as an arm or boom of a hydraulic excavator is controlled by switching the flow direction of the pressure oil to the hydraulic cylinder 5 which is a drive source of the driven part 2 by the switching valve 3. Further, when the driven part 2 is stopped, the supply and discharge of the pressure oil to and from the hydraulic cylinder 5 is stopped by the switching valve 3. In the stopped state of the operated part 2, the operated part 2 presses the piston rod 11 of the hydraulic cylinder 5 in the direction of pushing down by its own weight. Accordingly, the pressure oil held in the oil flow path 12 between the hydraulic cylinder 5 and the switching valve 3 leaks from a slight gap between the spool hole 10 and the spool 9 of the switching valve 3 by this pressing force. In this conventional hydraulic actuator system 1, the lock valve 4 is provided between the oil flow path 12 connecting the hydraulic cylinder 5 and the switching valve 3 and the cylinder side port 16 because there is a possibility of returning to the pressure oil tank 17. When the driven portion 2 is stopped, the lock valve 4 is closed to prevent the pressure oil from moving between the oil flow path 12 and the cylinder side port 16. Therefore, the dead weight of the driven part 2 reliably prevents the pressure oil in the hydraulic cylinder 5 and the oil flow path 12 from returning to the switching valve 3 side. When the driven part 2 is stopped, It is prevented from moving by its own weight.
[0003]
[Problems to be solved by the invention]
The lock valve 4 includes a housing 7 in which an insertion hole 8 is formed, and a valve body 13 that is slidably mounted in the insertion hole 8. When the valve body 13 is seated on the valve seat 14, the movement of the pressure oil is prevented between the oil flow path 12 and the cylinder side port 16, the operated part 2 is stopped, and the valve body 13 is moved to the valve seat 14. By moving away from the pressure oil, the pressure oil can move between the oil flow path 12 and the cylinder side port 16, and the operation of the operated part 2 becomes possible. In this hydraulic actuator system 1, the pressure of the hydraulic oil in the hydraulic cylinder 5, the hydraulic flow path 12 and the pressure oil chamber 15 rises due to the weight of the driven part 2 when the driven part 2 is stopped, for example, 70 to 350 kg / to rise to about cm ^2. Therefore, when the valve body 13 is separated from the valve seat 14, the high pressure pressure oil in the hydraulic cylinder 5, the oil passage 12 and the pressure oil chamber 15 suddenly flows to the switching valve 3 side. A pressure drop occurs, and the impact at this time is transmitted through the oil flow path, and for example, an impact sound such as “got” is generated. Therefore, the operator of the excavator makes an impact sound even though the operator is operating slowly, and is worried that the excavator may break down.
[0004]
Accordingly, an object of the present invention is to provide a hydraulic actuator system capable of preventing the generation of an impact sound when the stopped state of the operated part is released.
[0005]
[Means for Solving the Problems]
The present invention is interposed in a first switching valve 53 that switches between an operation position and a stop position of supply and discharge of pressure oil to and from a hydraulic actuator, and an oil passage that connects the hydraulic actuator and the switching valve, and opens and shuts off the oil passage. And a lock valve 54 for
When stopping the operated part of the hydraulic device operated by the hydraulic actuator against gravity, the first switching valve 53 is switched to the stop position, and the lock valve 54 is closed to shut off the oil flow path,
When operating the operated part, in the hydraulic actuator system that switches the first switching valve 53 to the operating position and opens the oil passage by opening the lock valve,
The lock valve is
(A) The housing 57, and the housing 57 includes
An insertion hole 74 having an axis 73;
A valve seat 64 having an axial line on the same straight line as the axial line 73 of the insertion hole 74 and having a cylindrical valve hole 81;
A first hydraulic chamber 76 provided between one end of the insertion hole 74 and the valve seat 64 and connected to a hydraulic actuator;
A housing 57 in which a second hydraulic chamber 77 provided on the opposite side to the first hydraulic chamber 76 with respect to the insertion hole 74 is formed;
(B) a valve body 63,
A cylindrical shape that is fitted in the insertion hole 74 coaxially with the axis 73, is slidable along the axis 73, has one end facing the first hydraulic chamber 76, and the other end facing the second hydraulic chamber 77. A base 82 of
An abacus ball-shaped seating portion 83 which is connected to the one end portion of the base portion 82 and is disposed in the first hydraulic chamber 76 and has a seat surface 91 seated on the valve seat 64;
A cylindrical protrusion 84 that is connected to an end of the seating portion 83 opposite to the base 82 and is inserted into the valve hole 81 and forms an annular gap 93 that functions as a throttle with the valve hole 81. A valve body 63 having,
(C) a spring member 95 that presses the base 82 toward the valve seat 64;
(D) The first hydraulic chamber side pressure receiving surface facing the first hydraulic chamber 76 of the valve body 63 in a state where the seat surface 91 of the valve body 63 is seated on the valve seat 64 is the second facing the second hydraulic chamber 77. It is configured to be smaller than the hydraulic chamber side pressure receiving surfaces 89, 90 by the area difference of the annular region 97,
A second switching valve 79 is provided, and this second switching valve 79 is
A first position connecting the first and second hydraulic chambers 76, 77;
A second position where the first hydraulic chamber 76 is shut off and the second hydraulic chamber 77 is connected to the tank 67 is switchable;
When releasing the stopped state of the operated portion, the first switching valve 53 is switched to the operating position, the second switching valve 79 is switched from the first position to the second position, and the valve body is moved from the valve seat. The hydraulic actuator system is characterized in that the hydraulic oil is moved in a separating direction and pressure oil is supplied and discharged through a gap between the valve seat and the protrusion.
[0006]
According to the present invention, the target operation of the hydraulic equipment operated by the hydraulic actuator when stopping against gravity, switching the first switching valve to the stop position Rutotomoni, the second switching valve 79 to the first position, Stop supplying and discharging pressure oil to the hydraulic actuator . B the valve body of the click valve seated on the valve seat, the movement of the pressure oil Ru is prevented between the hydraulic actuator and the first switching valve. Therefore, the pressure oil between the hydraulic actuator and the lock valve is held without leaking, and the operated part is reliably stopped against gravity. The columnar protrusion provided at the tip of the valve body is inserted into the cylindrical valve hole of the valve seat.
[0007]
When operating the target operation section, switching the first switching valve to the operating position Rutotomoni, the second switching valve 79 and the second position, to ready the supply and discharge of pressure oil to the hydraulic actuator. Valve body seated on the valve seat, you away from the valve seat. Therefore, when the operation of the operated part starts, a slight gap between the valve seat and the protrusion functions as an annular throttle in the hydraulic actuator, and pressure oil is supplied and discharged little by little. In other words, when the operated part stops, the pressure oil held between the hydraulic actuator and the switching valve moves slowly through a slight gap, preventing an instantaneous pressure drop. Prevents the generation of impact sound.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The hydraulic actuator system 51 of the present invention will be described with reference to FIGS. 1 is a diagram showing an overall configuration of a hydraulic actuator system 51 according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a region 68 surrounded by a virtual line in FIG. FIG. 3 is a cross-sectional view taken along the section line III-III in FIG. 2. The hydraulic actuator system 51 includes a first switching valve 53 that controls supply / discharge and stop of pressure oil to / from a hydraulic cylinder 55 that is a hydraulic actuator that drives an operated portion 52 such as an arm or boom of a hydraulic excavator, and the first switching valve 53. A lock valve 54 interposed between the switching valve 53 and the hydraulic cylinder 55 is included.
[0009]
The first switching valve 53 is a three-position three-port switching valve, and includes a spool hole 60 formed in the housing 57 and a spool 59 that is slidably fitted in the spool hole 60. 59 is provided coaxially with the first axis 72 of the spool hole 60. The housing 57 has a pump-side port 70, a cylinder-side port 75, and a tank-side port 71 that open to face the spool hole 60, along the first axis 72 (on the left side in FIG. 1). To the other side (right side in FIG. 1) in this order. A hydraulic pump 69 is connected to the pump side port 70, and a pressure oil tank 67 is connected to the tank side port 71.
[0010]
The lock valve 54 has a valve body 63 and an insertion hole 74 formed in the housing 57 and having a second axis 73 perpendicular to the first axis 72, and the valve body 63 is slid coaxially with the insertion hole 74. Fits freely.
[0011]
A small-diameter short cylindrical valve hole 81 is connected to one side of the insertion hole 74 in the second axis 73 direction (downward in FIG. 1). Further, the housing 57 has a first pressure oil chamber 76 and a second pressure oil chamber 77 that open to face the insertion hole 74 along the second axis 73 from one side (lower side in FIG. 1) to the other side ( They are formed in this order in the upper part of FIG. The first pressure oil chamber 76 and the second pressure oil chamber 77 are connected via an oil flow path 78 and a two-position three-port switching valve 79 (hereinafter referred to as a second switching valve 79) shown in FIG. Further, the first pressure oil chamber 76 is connected to the cylinder chamber 80 of the hydraulic cylinder 55 via the oil flow channel 66. In FIG. 1, the second switching valve 79 is omitted.
[0012]
A step formed on the wall surface of the first pressure oil chamber 76 on one side in the second axis 73 direction (downward in FIG. 1) functions as the valve seat 64. That is, the valve seat 64 in which the valve hole 81 is formed is provided on the insertion hole 74 side .
[0013]
As shown in FIG. 2, the valve body 63 has a cylindrical base portion in which a tapered surface 85 that is tapered toward the one side (downward in FIG. 2) is formed at one end portion in the second axis 73 direction. 82, a shaft portion 88 connected to one end portion of the base portion 82, an abacus ball-shaped seat portion 83 connected to one end portion of the shaft portion 88, and a circle connected to one end portion of the seat portion 83. And a columnar protrusion 84.
[0014]
The base portion 82 of the valve body 63 is fitted in the insertion hole 74 coaxially with the second axis 73 and is slidable along the second axis 73. A spring member 95 is mounted in the recess 96 of the base 82, and the spring member 95 presses the base 82 toward one side in the second axis 73 (downward in FIG. 2). The second pressure oil chamber 77 opens into the recess 96 of the base 82. Further, the tapered surface 85 side of the base portion 82, the shaft portion 88, and the seating portion 83 are disposed in the first pressure oil chamber 76. Further, the protrusion 84 is inserted into the valve hole 81 in a state where a slight annular gap 93 is opened between the valve seat 64 and the wall surface of the housing 57 facing the valve hole 81, coaxially with the second axis 73. Is done. Therefore, the valve hole 81 has an axis on the same straight line as the axis 73.
[0015]
As shown in FIG. 1, when the seat surface 91 on the lower side in the second axis 73 direction of the seat portion 83 is seated on the valve seat 64, the cylinder-side port 75 of the first switching valve 53 and the first pressure of the lock valve 54. The pressure oil is prevented from moving between the oil chamber 76. That is, the first switching valve 53 and the hydraulic cylinder 55 are shut off.
[0016]
The valve body 63 slides along the second axis 73 based on the pressure of the pressure oil in the first pressure oil chamber 76 and the second pressure oil chamber 77. More specifically, the pressure oil in the first pressure oil chamber 76 acts on the annular region 97 of the tapered surface 85 of the base 82 on the lower side in the second axis 73 direction, and the valve body 63 is applied with the first pressing force f1. Is pressed to the other side in the second axis 73 direction (upward in FIG. 2). The pressure oil in the second pressure oil chamber 77 acts on the first circular pressure receiving surface 89 and the second annular pressure receiving surface 90 of the base portion 82, and the valve body 63 is moved by the second pressing force f 2. Press toward one side (downward in FIG. 2) in the biaxial direction 73. That is, the valve body 63 is displaced along the second axis 73 due to the difference in the pressing force between the first pressing force f1 and the second pressing force f2.
[0017]
That is, when the second switching valve 79 is in the first position shown in FIG. 2, the first pressure oil chamber 76 and the second pressure oil chamber 77 are connected, and the pressure oil in the first pressure oil chamber 76 is It is fed to the two pressure oil chamber 77. Accordingly, since the pressure in the first pressure oil chamber 76 and the pressure in the second pressure oil chamber 77 are equal , the first and second valve bodies 63 in the state in which the seat surface 91 of the valve body 63 is seated on the valve seat 64. Due to the area difference between the pressure receiving surfaces facing the second hydraulic chambers 76 and 77 , the second pressing force f2 becomes larger than the first pressing force f1, and the valve body 63 is on the one side in the second axis 73 direction (downward in FIG. 2). And is seated on the valve seat 64. That is, the pressure receiving surface on the first hydraulic chamber 76 side facing the first hydraulic chamber 76 of the valve body 63 when the seat surface 91 of the valve body 63 is seated on the valve seat 64 is the second hydraulic pressure facing the second hydraulic chamber 77. It is configured to be smaller than the chamber 77 side pressure receiving surfaces 89 and 90 by an area difference 97. In this way, the first pressure oil chamber 76 and the first switching valve 53 are shut off.
[0018]
When the second switching valve 79 is switched to the second position, the first pressure oil chamber 76 and the second pressure oil chamber 77 are shut off, and the second pressure oil chamber 77 and the pressure oil tank 67 are connected. . Accordingly, since the pressure in the second pressure oil chamber 77 becomes the tank pressure, the first pressing force f1 becomes larger than the second pressing force f2, and the valve body 63 is on the other side in the second axis 73 direction (upward in FIG. 2). To disengage from the valve seat 64. Then, the first pressure oil chamber 76 and the cylinder side port 75 communicate with each other through a small annular gap 93, and the pressure oil can be moved between the hydraulic cylinder 55 and the first switching valve 53. .
[0019]
Next, the operation of the hydraulic actuator system 51 will be described. When the operated part 52 is stopped against gravity, the first switching valve 53 is switched to the stop position and the second switching valve 79 is switched to the first position. Then, the pump side port 70 and the tank side port 71 are disconnected from the cylinder side port 75. Further, since the first pressure oil chamber 76 and the second pressure oil chamber 77 are connected, the pressure oil in the first pressure oil chamber 76 is sent to the second pressure oil chamber 77. Accordingly, the pressures in the first pressure oil chamber 76 and the second pressure oil chamber 77 become equal, the second pressing force f2 overcomes the first pressing force f1, and the valve body 63 is one side in the second axis 73 direction (see FIG. 2 below). As a result, the seat surface 87 of the seating portion 83 of the valve body 63 is seated on the valve seat 64, and the movement of pressure oil is prevented between the first switching valve 53 and the hydraulic cylinder 55. Therefore, the pressure oil in the hydraulic cylinder 55, the first pressure oil chamber 76, and the second pressure oil chamber 77 is held without leaking, and the operated portion 52 is reliably stopped against gravity. 1 and 2 show the stopped state of the operated portion 52. FIG.
[0020]
When the operated part 52 is operated, particularly when the operated part 52 is raised, the first switching valve 53 is switched to the feeding position which is the operating position, and the second switching valve 79 is switched to the second position. Then, the pump side port 70 and the cylinder side port 75 are connected via the small diameter portion 92 (see FIG. 1) of the spool 59, and the cylinder side port 75 and the tank side port 71 are shut off. Further, the first pressure oil chamber 76 and the second pressure oil chamber 77 are blocked, and the second pressure oil chamber 77 is connected to the pressure oil tank 67. That is, the pressure oil in the second pressure oil chamber 77 is discharged to the pressure oil tank 67, the first pressing force f1 overcomes the second pressing force f2, and the valve body 63 is on the other side in the second axis 73 direction (FIG. 2). As a result, the first pressure oil chamber 76 and the cylinder side port 75 communicate with each other through the slight gap 93 between the protrusion 84 and the valve hole 81 so that the pressure oil can move. Accordingly, since this slight gap 93 functions as a throttle, the hydraulic oil fed from the hydraulic pump 69 is slowly and gradually supplied through the gap 93, the first pressure oil chamber 76 and the oil passage 66 little by little. 80. In this way, when the operated part 52 is raised from the stop state, it is possible to prevent the occurrence of a shocking sound “sounding” caused by suddenly feeding the pressure oil.
[0021]
When the operated part 52 is operated, particularly when the operated part 52 is lowered, the first switching valve 53 is switched to the discharge position which is the operating position, and the second switching valve 79 is switched to the second position. Then, the tank side port 71 and the cylinder side port 75 are connected via the small diameter portion 92 (see FIG. 1) of the spool 59, and the cylinder side port 75 and the pump side port 70 are shut off. Further, the first pressure oil chamber 76 and the second pressure oil chamber 77 are blocked, and the second pressure oil chamber 77 is connected to the pressure oil tank 67. That is, the pressure oil in the second pressure oil chamber 77 is discharged to the pressure oil tank 67, the first pressing force f1 overcomes the second pressing force f2, and the valve body 63 is located on the other side in the second axis 73 direction (FIG. 2). To the top). As a result, the first pressure oil chamber 76 and the cylinder side port 75 communicate with each other through the slight gap 93 between the protrusion 84 and the valve hole 81 so that the pressure oil can move. Therefore, since this slight gap 93 functions as a throttle, the pressure oil discharged from the hydraulic cylinder 80 is slowly and gradually supplied through the oil passage 66, the first pressure oil chamber 76, and the gap 93. It is discharged to 67. In this way, when the operated part 52 is lowered from the stopped state, it is possible to prevent the occurrence of a shocking sound “slamming” due to sudden pressure oil being discharged.
[0022]
As described above, the hydraulic actuator system 51 of the present invention can prevent the generation of impact sound with a simple configuration in which the cylindrical protrusion 84 is formed continuously with the seating portion 83 of the valve body 63. . Therefore, the number of parts hardly increases, and an increase in cost can be suppressed to prevent generation of impact sound.
[0023]
【The invention's effect】
According to the present invention, when the operated part of the hydraulic device operated by the hydraulic actuator is stopped against gravity, the first switching valve is switched to the stop position, the second switching valve 79 is set to the first position, and the lock is applied. The valve body of the valve is seated on the valve seat to prevent the pressure oil from moving between the hydraulic actuator and the first switching valve. Therefore, the pressure oil is held between the hydraulic actuator and the lock valve without leaking, and the operated part is reliably stopped against gravity. When the operated part is operated, the first switching valve is switched to the operating position, and the second switching valve 79 is set to the second position so that the valve element seated on the valve seat of the lock valve is separated from the valve seat. Then, at the start of the operation of the operated part, the hydraulic actuator passes through a slight gap between the valve seat and the protrusion, and the pressure oil is supplied and discharged little by little to prevent an instantaneous pressure drop. . This prevents the generation of impact sound.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a hydraulic actuator system 51 according to an embodiment of the present invention.
2 is an enlarged view of a region 68 surrounded by a virtual line in FIG.
3 is a cross-sectional view taken along section line III-III in FIG. 2. FIG.
FIG. 4 is a diagram showing a hydraulic actuator system 1 of a reference example .
[Explanation of symbols]
51 Hydraulic Actuator System 52 Operated Part 53 First Switching Valve 54 Lock Valve 55 Hydraulic Cylinder 63 Valve Element 64 Valve Seat 74 Insertion Hole 81 Valve Hole 83 Projection 93 Gap

Claims

A first switching valve 53 that switches between an operation position and a stop position of supply and discharge of pressure oil to and from the hydraulic actuator, and a lock valve 54 that is interposed in an oil passage that connects the hydraulic actuator and the switching valve, and that opens and closes the oil passage. And
When stopping the operated part of the hydraulic device operated by the hydraulic actuator against gravity, the first switching valve 53 is switched to the stop position, the lock valve 54 is closed to shut off the oil flow path,
When operating the operated part, in the hydraulic actuator system that switches the first switching valve 53 to the operating position and opens the oil flow path by opening the lock valve,
The lock valve is
(A) The housing 57, and the housing 57 includes
An insertion hole 74 having an axis 73;
A valve seat 64 having an axial line on the same straight line as the axial line 73 of the insertion hole 74 and having a cylindrical valve hole 81;
A first hydraulic chamber 76 provided between one end of the insertion hole 74 and the valve seat 64 and connected to a hydraulic actuator;
A housing 57 in which a second hydraulic chamber 77 provided on the opposite side to the first hydraulic chamber 76 with respect to the insertion hole 74 is formed;
(B) a valve body 63,
A cylindrical shape that is fitted in the insertion hole 74 coaxially with the axis 73, is slidable along the axis 73, has one end facing the first hydraulic chamber 76, and the other end facing the second hydraulic chamber 77. A base 82 of
An abacus ball-shaped seating portion 83 that is connected to the one end portion of the base portion 82 and is disposed in the first hydraulic chamber 76 and has a seat surface 91 seated on the valve seat 64;
A cylindrical protrusion 84 that is connected to the end of the seating portion 83 opposite to the base 82 and is inserted into the valve hole 81 and forms an annular gap 93 that functions as a throttle with the valve hole 81. A valve body 63 having,
(C) a spring member 95 that presses the base 82 toward the valve seat 64;
(D) The first hydraulic chamber side pressure receiving surface facing the first hydraulic chamber 76 of the valve body 63 in a state where the seat surface 91 of the valve body 63 is seated on the valve seat 64 is the second facing the second hydraulic chamber 77. It is configured to be smaller than the hydraulic chamber side pressure receiving surfaces 89, 90 by the area difference of the annular region 97,
A second switching valve 79 is provided, and this second switching valve 79 is
A first position connecting the first and second hydraulic chambers 76, 77;
A second position where the first hydraulic chamber 76 is shut off and the second hydraulic chamber 77 is connected to the tank 67 is switchable;
When releasing the stopped state of the operated part, the first switching valve 53 is switched to the operating position, the second switching valve 79 is switched from the first position to the second position, and the valve body is moved from the valve seat. A hydraulic actuator system that moves in a separating direction and supplies and discharges pressure oil through a gap between a valve seat and a protrusion.