JP3594680B2 - Hydraulic regenerator of hydraulic machine - Google Patents

Hydraulic regenerator of hydraulic machine Download PDF

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Publication number
JP3594680B2
JP3594680B2 JP2420795A JP2420795A JP3594680B2 JP 3594680 B2 JP3594680 B2 JP 3594680B2 JP 2420795 A JP2420795 A JP 2420795A JP 2420795 A JP2420795 A JP 2420795A JP 3594680 B2 JP3594680 B2 JP 3594680B2
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pressure
hydraulic
predetermined
pump
load operation
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JPH08219107A (en
Inventor
司 豊岡
東一 平田
玄六 杉山
滋博 吉永
広二 石川
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Hitachi Construction Machinery Co Ltd
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Hitachi Construction Machinery Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/024—Systems essentially incorporating special features for controlling the speed or actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • F15B2211/20515—Electric motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • F15B2211/3058—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve having additional valves for interconnecting the fluid chambers of a double-acting actuator, e.g. for regeneration mode or for floating mode
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
    • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/35—Directional control combined with flow control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/355—Pilot pressure control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6654—Flow rate control

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Operation Control Of Excavators (AREA)
  • Fluid-Pressure Circuits (AREA)

Description

【０００１】
【産業上の利用分野】
本発明は、油圧ショベル等の油圧機械に備えられ、アクチュエータからの戻り油を当該アクチュエータに再生供給可能な油圧再生装置に関する。
【０００２】
【従来の技術】
この種の油圧機械の油圧再生装置として、特公平４−５９４８４号公報に記載のものがある。図５は、この従来技術を示す回路図である。同図５に示すように、この従来技術は、油圧ポンプ１及びパイロットポンプ１ａと、油圧ポンプ１から吐出される圧油によって駆動するアクチュエータ、すなわちボトム側室Ｃ及びロッド側室Ｄを有する油圧シリンダ２と、油圧ポンプ１から油圧シリンダ２に供給される圧油の流れを制御し、左側切換位置３ａ、右側切換位置３ｂを有する方向切換弁３とを備えている。
【０００３】
油圧シリンダ２を伸長させる方向に駆動する切換位置である方向切換弁３の左側切換位置３ａには、タンクに連絡されるタンク側通路、すなわち排出通路６と、油圧ポンプ１に連絡されるポンプ側通路、すなわち供給通路５と、これらの供給通路５と排出通路６とを連絡する連絡通路１０と、この連絡通路１０に設けられ、排出通路６から供給通路５への圧油の供給を許容させる許容手段、すなわちチェック弁７と、タンクに導かれる圧油の流量を制御する流量制御手段、すなわち排出通路６を選択的に遮断する合流切換装置８と、供給通路５に連通し合流切換装置８を駆動する圧力信号を導く圧力検出手段、すなわち圧力検出通路９とを設けてある。また、パイロットポンプ１ａのパイロット圧を外部圧力信号Ｐｃとして、すなわち設定圧力として前述の圧力検出通路９で導かれる圧力信号に対抗するように合流切換装置８に供給する当該合流切換装置８の駆動手段、すなわち外部圧力信号発生装置１５を備えている。
【０００４】
このように構成した従来技術では、方向切換弁３を左側切換位置３ａに切換えると、油圧ポンプ１から吐出された圧油は供給通路５を経て油圧シリンダ２のボトム室側Ｃに導かれる。また油圧シリンダ２のロッド側室Ｄ内から流出した圧油は、排出通路６を経てタンクに導かれる。このとき、供給通路５内の圧力が圧力検出通路９に導かれ、この圧力信号が外部圧力信号発生装置１５で設定される外部圧力信号Ｐｃよりも低い場合、合流切換装置８が排出通路６を遮断するように駆動し、油圧シリンダ２のロッド側室Ｄからの戻り油の全量が排出通路６から供給通路５にチェック弁７を介して導かれ、供給通路５の流量に合流する。これにより、油圧シリンダ２の作動速度を増速させることができる。
【０００５】
また、油圧シリンダ２の負荷圧が大きくなり、供給通路５の圧力が上昇し、圧力検出通路９に導かれる圧力信号が外部圧力信号発生装置１５で設定される外部圧力信号Ｐｃよりも高くなると、合流切換装置８が排出通路６を連通させるように駆動し、排出通路６がタンクに連通する。したがつて、油圧シリンダ２のロッド側室Ｄからの戻り油は供給通路５に合流されることなくタンクに戻される。これにより、油圧シリンダ２の増速は抑えられ、通常速度に保たれる。
【０００６】
このように図５に示す従来技術では、油圧シリンダ２の伸長時に発生する負荷圧力が設定圧力以下のときは、油圧シリンダ２のロッド側室Ｄからの戻り油の全量がボトム側室Ｃに再生合流して油圧シリンダ２は通常速度に比べて増速し、また、油圧シリンダ２の伸長時に発生する負荷圧力が設定圧力より大きいときは、油圧シリンダ２は通常速度に保持されるようになっている。
【０００７】
【発明が解決しようとする課題】
ところで、油圧機械にあっては、大きな負荷圧が要求される重負荷作業と、負荷圧は比較的小さく、速い作業速度が要求される軽負荷作業とを選択的に実施するものがある。例えば、油圧機械が油圧ショベルである場合には、１台の油圧ショベルにおいて、軽負荷作業である「表土はぎ作業」と、重負荷作業である「溝掘削作業」とを選択的に実施することがしばしばおこなわれている。この場合、上述した図５に示す従来技術では、重負荷作業である「溝掘削作業」を実施するためには、大きな推力が要求され、したがって設定圧力すなわち外部圧力信号Ｐｃの値をできるだけ低く設定して、低い負荷圧のうちに再生解除させる必要がある。また逆に、軽負荷作業である「表土はぎ作業」では大きな推力は要求されず、速い作業速度を得るために圧力信号Ｐｃの値をできるだけ高めに設定することが好ましい。
【０００８】
したがって、上述した従来技術は、重負荷作業である「溝掘削作業」を考慮して外部圧力信号Ｐｃの値をあらかじめ低く設定すると、「表土はぎ作業」を実施したときには、その作業速度、すなわち、油圧シリンダ２の作動速度が遅くなり、この軽負荷作業である「表土はぎ作業」の作業能率が低下してしまう。また逆に、軽負荷作業である「表土はぎ作業」を考慮して外部圧力信号Ｐｃの値をあらかじめ高く設定すると、「溝掘削作業」においては大きな推力が得られず、この重負荷作業である「溝掘削作業」の作業能率が低下することになる。このように、従来技術では、外部圧力信号Ｐｃの値を重負荷作業、軽負荷作業のどちらかを考慮して一義的に決定せざるを得ないことから、１台の油圧機械で重負荷作業、軽負荷作業の双方の作業能率を向上させることは困難であった。
【０００９】
なお、このようなことは１つの連続した作業中でも起り得る。例えば、速い作業速度が求められる「表土はぎ作業」を考慮して、外部圧力信号Ｐｃの値をあらかじめ高く設定して「表土はぎ作業」を実施しているときに、当該油圧ショベルのバケットが、硬い地盤に当った場合には、外部圧力信号Ｐｃの値を高く設定してあるために大きな推力が得られず、油圧シリンダ２の停止等を生じてしまい、作業の能率低下を招いてしまう。
【００１０】
本発明は、上記した従来技術における実情に鑑みてなされたもので、その目的は、アクチュエータの作動を介して重負荷作業と軽負荷作業を選択的に実施し得る油圧機械にあって、重負荷作業及び軽負荷作業のいずれか所望の作業に好適なアクチュエータの駆動制御を容易に実現させることができる油圧機械の油圧再生装置を提供することにある。
【００１１】
【課題を解決するための手段】
この目的を達成するために、本発明の請求項１に係る発明を、図１〜３に示す実施例中で使用されている符号を参照して説明すると以下のようになる。
【００１２】
本発明は、油圧ポンプ１及びタンク３０と、上記油圧ポンプ１から吐出される圧油によって駆動するアクチュエータ、例えば油圧シリンダ２と、上記油圧ポンプ１から上記油圧シリンダ２に供給される圧油の流れを制御する方向切換弁２０と、油圧シリンダ２とタンク３０とを連絡するタンク側通路２３と、上記タンク３０に導かれる圧油の流量を制御する流量制御手段、例えば可変絞り２５と、上記油圧ポンプ１と油圧シリンダ２とを連絡するポンプ側通路２８と、このポンプ側通路２８とタンク側通路２３とを連絡する連絡通路２４と、この連絡通路２４に設けられ、タンク側通路２３内の圧力がポンプ側通路２８内の圧力よりも高いとき、タンク側通路２３からポンプ側通路２８への圧油の供給を許容させるチェック弁２１と、油圧シリンダ２に供給される圧油の圧力を検出する検出手段、例えば油圧ポンプ１の吐出圧を検出する圧力検出器２９と、上記の可変絞り２５を駆動する駆動手段、例えば電磁比例減圧弁４０とを備え、連絡通路２４を介して油圧シリンダ２からの戻り油をポンプ側通路２８に合流させる再生操作が可能な構成を基本構成としている。
【００１３】
この基本構成に加えて、本願発明は、上述した圧力検出器２９からの圧力信号ＰＤを入力し、その圧力信号ＰＤに応じた作動信号ｉｓを上述した電磁比例減圧弁４０に出力する制御装置４４を備え、この制御装置４４が、上記圧力信号ＰＤと、上記作動信号ｉｓに対応する目標値、例えば目標電流ｉとの関数関係を、所定の重負荷作業に対応する関数関係１０１、及び所定の軽負荷作業に対応する関数関係１００として、あらかじめ複数設定する記憶部６２と、上記圧力信号ＰＤと上記記憶部６２に記憶された関数関係１０１，１００とに基づいて、該当する上述の目標電流ｉを演算する演算部６１とを有する。上記した記憶部６２に上記圧力信号ＰＤの所定値に対応する所定圧力（図３のＰｄ ２ ）をあらかじめ記憶させるとともに、上記記憶部６２に記憶される上記所定の重負荷作業に対応する関数関係１０１、及び上記所定の軽負荷作業に対応する関数関係１００を、上記圧力信号ＰＤの値が上記記憶部６２に記憶される上記所定圧力（図３のＰｄ ２ ）に至った際に、上記所定の重負荷作業に対応する関数関係１０１は再生操作を解除する関数関係となるように設定し、上記所定の軽負荷作業に対応する関数関係１００は再生操作をおこなわせる関数関係となるように設定してある。
【００１４】
また、上記所定の重負荷作業及び所定の軽負荷作業のそれぞれに相当する指示信号ＭＳを上記制御装置４４に出力可能な指示装置、例えば作業モードスイッチ４１を備えている。
【００１５】
そして、上記制御装置４４の演算部６１は、上記作業モードスイッチ４１から出力される指示信号ＭＳに応じて、上記記憶部６２に記憶されている所定の重負荷作業に対応する関数関係１０１、所定の軽負荷作業に対応する関数関係１００のうちの該当する関数関係に基づいて目標電流ｉを求める演算をおこなう構成にしてある。
【００１６】
【作用】
本発明の請求項１に係る発明は、上記した構成にしてあることから、例えば油圧ショベルにおける「溝掘削作業」などの重負荷作業を実施する場合には、指示装置である作業モードスイッチ４１を操作して、重負荷作業に対応する指示信号ＭＳを出力させ、方向切換弁２０の切換え操作をおこなえばよい。作業モードスイッチ４１から出力される指示信号ＭＳに応じて、制御装置４４の演算部６１は、記憶部６２に記憶されている図３に示す重負荷作業に対応する関数関係１０１と、圧力検出器２９から出力される圧力信号ＰＤとに基づいて目標電流ｉを求める演算をおこなう。
【００１７】
ここで、重負荷作業に対応する関数関係１０１は、圧力信号ＰＤの値が比較的小さいときに、流量制御手段である可変絞り２５を全開にし得るような関数関係、つまり、圧力信号ＰＤの値が比較的小さい（図３のＰｄ２）ときに再生操作を解除し得る関数関係である。
【００１８】
このような関数関係１０１に基づく目標電流ｉに相当する駆動信号ｉｓが、制御装置４４から駆動手段である電磁比例減圧弁４０に出力される。これにより電磁比例減圧弁４０が駆動して、可変絞り２５は圧力信号ＰＤが比較的小さい（図３のＰｄ２）ときに全開となり、タンク側通路２３を全量通過させるように作動する。これにより、再生操作が解除される状態となる。したがって、ポンプ側通路２８、方向切換弁２０を介してアクチュエータである油圧シリンダ２に油圧ポンプ１の圧油を供給し、方向切換弁２０、タンク側通路２３を介して油圧シリンダ２の戻り油を全量タンク３０に戻すことができる。これにより、大きな推力が得られ、重負荷作業に対応させることができる。
【００１９】
また、例えば油圧ショベルにおける「表土はぎ作業」などの軽負荷作業を実施する場合には、指示装置である作業モードスイッチ４１を操作して、軽負荷作業に対応する指示信号ＭＳを出力させ、方向切換弁２０の切換え操作をおこなえばよい。作業モードスイッチ４１から出力される指示信号ＭＳに応じて制御装置４４の演算部６１は、記憶部６２に記憶されている図３に示す軽負荷作業に対応する関数関係１００と、圧力検出器２９から出力される圧力信号ＰＤとに基づいて目標電流ｉを求める演算をおこなう。
【００２０】
ここで、軽負荷作業に対応する関数関係１００は、圧力信号ＰＤの値が比較的小さい間（例えば図３のＰｄ２）は流量制御手段である可変絞り弁２５を全開にしないような関数関係、つまり圧力信号ＰＤの値が比較的小さい間（例えば図３のＰｄ２）は再生操作を可能とさせる関数関係である。
【００２１】
このような関数関係１００に基づく目標電流ｉに相応する駆動信号ｉｓが制御装置４４から駆動手段である電磁比例減圧弁４０に出力される。これにより、電磁比例減圧弁４０が駆動して可変絞り２５は、圧力信号ＰＤの値が小さいとき（例えば図３のＰｄ２）には全開とはならず、タンク側通路２３の油のタンク３０への流入を規制する。これに伴い、タンク側通路２３の圧力が上昇し、再生操作が可能な状態となる。タンク側通路２３の圧力がポンプ側通路２８の圧力よりも大きくなったとき、タンク側通路２３の圧油が連絡通路２４、チェック弁２１を介してポンプ側通路２８に合流する。したがって、油圧シリンダ２の戻り油と、油圧ポンプ１から吐出される圧油との合流された圧油が油圧シリンダ２に供給される。これにより、上述した重負荷作業時の油圧シリンダ２の作動速度である通常速度に比べて、速い作動速度で油圧シリンダ２を駆動させることができ、軽負荷作業に対応させることができる。
【００２２】
【実施例】
以下、本発明の油圧機械の油圧再生装置の実施例を図に基づいて説明する。 図１〜４は本発明の請求項１〜７に相当する油圧機械の油圧再生装置の一実施例を示す図で、図１は全体構成を示す回路図、図２は図１に示す実施例に備えられる制御装置の構成を示す図、図３は図２に示す制御装置の記憶部及び演算部の構成を示す図、図４は図１に示す実施例で得られる特性を示す図である。
【００２３】
本実施例は例えば油圧ショベルに適用されるもので、図１に示すように、エンジン４３と、このエンジン４３によって駆動する油圧ポンプ１と、タンク３０と、油圧ポンプ１から吐出される圧油によって駆動するブームシリンダ、アームシリンダ、バケットシリンダ等のアクチュエータ、すなわち油圧シリンダ２と、油圧ポンプ１から油圧シリンダ２に供給される圧油の流量を制御する方向切換弁２０とを備えている。方向切換弁２０は、中立位置と、油圧シリンダ２のボトム側室Ｃに圧油を供給可能な切換位置２０ａと、油圧シリンダ２のロッド側室Ｄに圧油を供給可能な切換位置２０ｂとを有する。この方向切換弁２０は、パイロット弁７０の操作レバー７１を操作することにより、選択的に出力されるパイロット圧Ｐａ，Ｐｂにより切換位置２０ａ，２０ｂのいずれかに切換えられる。
【００２４】
また、油圧シリンダ２とタンク３０とを連絡するタンク側通路２３と、このタンク側通路２３に配置され、タンク３０に導かれる圧油の流量を制御する流量制御手段、例えば油圧操作式の可変絞り２５とを備えている。この可変絞り２５は、連通位置２５ａと絞り位置２５ｂとを有する。
【００２５】
また、油圧ポンプ１と油圧シリンダ２とを連絡するポンプ側通路２８と、このポンプ側通路２８とタンク側通路２３とを連絡する連絡通路２４と、この連絡通路２４に設けられ、タンク側通路２３内の圧力がポンプ側通路２８内の圧力よりも高いときに、タンク側通路２３からポンプ側通路２８への圧油の供給を許容させ、ポンプ側通路２８からタンク側通路２３方向への圧油の流れを阻止するチェック弁２１と、ポンプ側通路２８に設けられ、油圧ポンプ１から方向切換弁２０方向への圧油の流れを許容させ、方向切換弁２０から油圧ポンプ１方向への圧油の流れを阻止するチェック弁２２とを備えている。
【００２６】
また、油圧シリンダ２に供給される圧油の圧力を検出する検出手段、例えば油圧ポンプ１の吐出圧Ｐｄを検出し、圧力信号すなわちポンプ吐出圧信号ＰＤを出力する圧力検出器２９と、上述した可変絞り２５を駆動する駆動手段、例えば可変絞り２５のパイロット室にパイロット圧Ｐｉを出力する電磁比例減圧弁４０とを備えている。
【００２７】
そして特に、本実施例では、圧力検出器２９から出力されるポンプ吐出圧信号ＰＤを入力し、そのポンプ吐出圧信号ＰＤに応じた作動信号ｉｓを上述した電磁比例減圧弁４０に出力する制御装置４４と、重負荷作業及び軽負荷作業のうちのいずれかを指示する指示装置、例えば選択された作業モードに相当する指示信号ＭＳを出力する作業モードスイッチ４１とを備えている。
【００２８】
上述した制御装置４４は、図２に示すように、圧力検出器２９から出力されるポンプ吐出圧信号ＰＤ、及び作業モードスイッチ４１から出力される指示信号ＭＳを入力する入力部６０と、上述したポンプ吐出圧信号ＰＤと電磁比例減圧弁４０を作動させる作動信号ｉｓに対応する目標値、例えば目標電流ｉとの関数関係が、重負荷作業及び軽負荷作業のそれぞれに対応してあらかじめ複数設定される記憶部６２と、電磁比例減圧弁４０を駆動するための目標電流ｉを求める演算をおこなう演算部６１と、この演算部６１で求められた目標電流ｉに相当する作動信号ｉｓを電磁比例減圧弁４０に出力する出力部６３とを備えている。
【００２９】
上述した制御装置４４の記憶部６２には、例えば図３に示す軽負荷作業に対応する関数関係１００と重負荷作業に対応する関数関係１０１とが設定されている。このうち、重負荷作業に対応する関数関係１０１は、ポンプ吐出圧信号ＰＤが、所定の低い第１の設定圧力Ｐｄ１に至るまでは高い一定の目標電流ｉ１を出力し、ポンプ吐出圧信号ＰＤが第１の設定圧力Ｐｄ１を越えて第２の設定圧力Ｐｄ２に至るまでは、ｉ０＜ｉ＜ｉ１、となる目標電流ｉを出力し、ポンプ吐出圧信号ＰＤが第２の設定圧力Ｐｄ２以上になると、電流値ｉ０＝０の目標電流ｉを出力する関数関係である。また、軽負荷作業に対応する関数関係１００は、ポンプ吐出圧信号ＰＤが前述した所定の低い第１の設定圧力Ｐｄ１に至るまでは高い一定の目標電流ｉ１を出力し、ポンプ吐出圧信号Ｐｄが前述した第２の設定圧力Ｐｄ２よりも大きい第３の設定圧力Ｐｄ３に至るまでは、ポンプ吐出圧信号ＰＤの増加に応じて減少する目標電流ｉ（ｉ０＜ｉ＜ｉ１）を出力し、ポンプ吐出圧信号ＰＤが第３の設定圧力Ｐｄ３以上になると、ｉ０＝０の目標電流ｉを出力する関数関係である。すなわち、重負荷作業に対応する関数関係１０１のゲインを、軽負荷作業に対応する関数関係１００のゲインに比べて、あらかじめ大きく設定してある。
【００３０】
また、上述した制御装置４４の演算部６１は、作業モードスイッチ４１から出力される指示信号ＭＳに応じて、記憶部６２に記憶されている前述した重負荷作業に対応する関数関係１０１、軽負荷作業に対応する関数関係１００のうちの該当する関数関係と、圧力検出器２９から出力されるポンプ吐出圧信号ＰＤとに基づいて、目標電流ｉを求める演算をおこなう。
【００３１】
このように構成した実施例の動作は以下のとおりである。
例えば、「溝掘削作業」を考慮して図１に示す作業モードスイッチ４１で重負荷作業が選択されたとすると、この作業モードスイッチ４１から重負荷作業に対応する指示信号ＭＳが図２，３に示す制御装置４４の入力部６０に出力されることにより、制御装置４４の記憶部６２に記憶されている関数関係１００，１０１のうちの重負荷作業に対応する関数関係１０１が選定され、制御装置４４の演算部６１は、この重負荷作業に対応する関数関係１０１と、圧力検出器２９から出力されるポンプ吐出圧信号ＰＤとに基づいて、図１に示す電磁比例減圧弁４０を作動させる作動信号ｉｓの目標値、すなわち目標電流ｉを求める演算をおこなうことになる。
【００３２】
この状態において、パイロット弁７０の操作レバー７１を例えば図１のＡ側に操作すると、パイロット圧Ｐａが発生し、このパイロット圧Ｐａが方向切換弁２０の同図１の左側に位置するパイロット室に与えられ、方向切換弁２０が切換位置２０ａに切換えられる。これにより、油圧ポンプ１から吐出される圧油は、ポンプ側通路２８、チェック弁２２、方向切換弁２０の切換位置２０ａを経て油圧シリンダ２のボトム側室Ｃに供給され、ロッド側室Ｄからの戻り油は方向切換弁２０の切換位置２０ａ、タンク側通路２３、可変絞り２５を介してタンク３０に戻される。
【００３３】
このとき、圧力検出器２９によって検出されるポンプ吐出圧信号ＰＤが、前述した図３に示す記憶部６２に記憶される関数関係１０１の第１の設定圧力Ｐｄ１よりも低い間は、演算部６１で高い一定の目標電流（ｉ＝ｉ１）が求められ、この目標電流（ｉ＝ｉ１）に相当する作動信号（ｉｓ＝ｉ１）が制御装置４４の出力部６３から電磁比例減圧弁４０の駆動部に出力される。これにより、電磁比例減圧弁４０から出力されるパイロット圧ｐｉは最小となり、可変絞り２５に備えられるばねの力により当該可変絞り２５は図４の（ａ）の最大絞り量を与え得る絞り位置２５ｂに保持され、タンク側通路２３には可変絞り２５の絞り量に応じた圧力が発生する。そして、このタンク側通路２３内の圧力が、ポンプ側通路２８の圧力以上になると、油圧シリンダ２のロッド側室Ｄからの戻り油の一部は、連絡通路２４、チェック弁２１を介してポンプ側通路２８に流れ、この戻り油が油圧ポンプ１から吐出される圧油と合流して油圧シリンダ２のボトム側室Ｃに供給される操作がおこなわれる。したがって、油圧シリンダ２のボトム側室Ｃに流入する流量は、連絡通路２４から流れ込んだ図４の（ｂ）に示す最大の再生流量分だけ増加し、それに応じて油圧シリンダ２の作動速度を速くすることができる。
【００３４】
このような状態から、当該油圧ショベルのバケットが土砂にくい込み「溝掘削作業」が実施されて、油圧シリンダ２にかかる負荷が大きくなると、油圧ポンプ１の吐出圧Ｐｄが大きくなり、圧力検出器２９から出力されるポンプ吐出圧信号ＰＤの値も大きくなる。このポンプ吐出圧信号ＰＤの値が図３の関数関係１０１の第１の設定圧力Ｐｄ１と第２の設定圧力Ｐｄ２の間にあるときには、制御装置４４の演算部６１で求められる目標電流ｉは、ｉ０＜ｉ＜ｉ１の値をとり、制御装置４４の出力部６３から出力される作動信号ｉｓも、ｉ０＜ｉｓ＝ｉ＜ｉ１、の値となり、これにより電磁比例減圧弁４０から出力されるパイロット圧Ｐｉの値が増加し、可変絞り２５は、図４の（ａ）で示すようにその絞り量を小さく変化させるように、すなわち閉じられ気味の状態から開かれる方向に変化させるように駆動し、タンク３０に戻される油量が増加し、再生流量が図４の（ｂ）で示すように次第に減少する状態となる。すなわち、油圧シリンダ２の作動速度は、それまでに比べて若干遅くなるものの、より大きな推力を得ることができる状態となる。
【００３５】
そしてさらに、ポンプ吐出圧信号ＰＤの値が図３の関数関係１０１の第２の設定圧力Ｐｄ２以上になると、制御装置４４の演算部６１で求められる目標電流ｉは、ｉ＝ｉ０となり、出力部６３から出力される作動信号ｉｓも、ｉｓ＝ｉ＝ｉ０となり、これにより電磁比例減圧弁４０から出力されるパイロット圧Ｐｉの値は最大となり、可変絞り２５は、図４の（ａ）に示すように絞り量を０とする全開となる切換位置２５ａに切換えられる。これにより、図４の（ｂ）に示すように再生流量が０となって、タンク側通路２３の全量がタンク３０に戻される再生解除状態となり、その結果、油圧シリンダ２のロッド側室Ｄの圧力が小さくなり、このため油圧シリンダ２の推力が増大し、掘削力を急激に増加させ、所望の重負荷作業である「溝掘削作業」を実施することができる。
【００３６】
また、例えば「表土はぎ作業」あるいは地面を平坦にならす「ならし作業」等を考慮して、作業モードスイッチ４１により軽負荷作業が選択されたとすると、この作業モードスイッチ４１から軽負荷作業に対応する指示信号ＭＳが制御装置４４の入力部６０に出力される。これにより、制御装置４４の記憶部６２に記憶される関数関係１００，１０１のうちの軽負荷作業に対応する関数関係１００が選定され、制御装置４４の記憶部６１は、この軽負荷作業に対応する関数関係１００と、圧力検出器２９から出力されるポンプ吐出圧信号ＰＤに基づいて、目標電流ｉを求める演算をおこなう。この状態にあって、操作レバー７１が操作され、方向切換弁２０が例えば切換位置２０ａに切換えられると、前述したように、油圧シリンダ２のボトム側室Ｃに圧油が供給され、油圧シリンダ２は伸長する方向に作動する。
【００３７】
このとき、圧力検出器２９によって検出されるポンプ吐出圧信号ＰＤが第１の設定圧力Ｐｄ１よりも低い間は、前述したように可変絞り２５は図４の（ａ）で示す最大絞り量を与え得る絞り位置２５ｂに保持され、タンク側通路２３に可変絞り２５の絞り量に応じた圧力が発生可能となり、図４の（ｂ）で示す最大の再生流量が確保され、所望の再生操作をおこなうことができる。すなわち、油圧シリンダ２のボトム側室Ｃに、この油圧シリンダ２の戻り油と油圧ポンプ１から吐出される圧油とを合流して供給でき、油圧シリンダ２の作動速度を速くして所望の「表土はぎ作業」等の軽負荷作業をおこなうことができる。なお、図示しないバケット先端に当る土砂等の抵抗により、若干負荷圧が大きくなり、圧力検出器２９から出力されるポンプ吐出圧信号ＰＤの値が仮に第２の設定圧力Ｐｄ２程度になったとしても、この軽負荷作業に係る関数関係１００のゲインは、前述した重負荷作業に係る関数関係１０１のゲインに比べてあらかじめ小さく設定してあるので、演算部６１で求められる目標電流ｉは、ｉ０＜ｉ＜ｉ１、の値をとり、出力部６３から出力される作動信号ｉｓも、ｉ０＜ｉｓ＝ｉ＜ｉ１、となり、これに伴って電磁比例減圧弁４０から出力されるパイロット圧Ｐｉは、最小＜Ｐｉ＜最大、となり、可変絞り２５は図４の（ａ）の特性線上に位置する絞り量を保有した状態に維持される。したがって、再生流量は図４の（ｂ）で示すように若干減少するものの、再生操作を継続させることができる。
【００３８】
そして、このような「表土はぎ作業」等の軽負荷作業中に、重負荷作業に相当する事態が生じたとき、例えば、図示しないバケットの先端が硬い地盤にくい込んでしまったときなどにあっては、負荷圧の増加に応じて油圧ポンプ１の吐出圧ｐｄが増加することから、圧力検出器２９で検出されるポンプ吐出圧信号ＰＤの値が大きくなり、例えば第３の設定圧力Ｐｄ３以上になることがある。このような事態を生じたときには、ｉ＝ｉ０、となり、出力部６３から出力される作動信号ｉｓも、ｉｓ＝ｉ＝ｉ０、となり、電磁比例減圧弁４０から出力されるパイロット圧Ｐｉが最大となり、可変絞り２５は図４の（ａ）で示すように絞り量をほぼ０とする連通位置２５ａに切換えられ、タンク側通路２３の全量がタンク３０に戻される再生解除状態となる。この状態では、図４の（ｂ）に示すように再生流量がなくなり、油圧シリンダ２のロッド側室Ｄがタンク３０に連通して、前述したように油圧シリンダ２の大きな推力を確保することができ、硬い地盤にくい込んだバケットを動かして、その硬い地盤から脱出する動作をおこなわせることができる。すなわち、油圧シリンダ２の停止による作業の停止を招かずに、引き続いて「表土はぎ作業」等の軽負荷作業を実施させることができる。
【００３９】
このように構成した実施例にあっては、上述のように作業モードスイッチ４１により選択される制御装置４４の関数関係１００，１０１に応じて、１台の油圧ショベルで軽負荷作業と重負荷作業の双方に好適な油圧シリンダ２の駆動制御をおこなうことができ、これにより、軽負荷作業と重負荷作業の双方の作業能率を向上させることができる。
【００４０】
なお、上記実施例では、油圧ポンプ１の吐出圧Ｐｄを検出する圧力検出器２９を設け、この圧力検出器２９から出力されるポンプ吐出圧信号ＰＤに基づいて、再生操作及び再生解除操作をおこなうように構成してあるが、本発明は、これに限られず、例えば方向切換弁２０と油圧シリンダ２との間に位置する主管路に負荷圧を検出する圧力検出器を設け、その圧力検出器から出力される圧力信号に基づいて、再生操作及び再生解除操作をおこなう構成にしてもよい。
【００４１】
また、上記実施例では、アクチュエータとして油圧シリンダ２を例に挙げて説明したが、この油圧シリンダ２に代えて油圧モータを設けた構成であってもよい。 また上記では、油圧機械として油圧ショベルを挙げたが、本発明は、このような油圧ショベルには限られず、油圧操作式クレーン等にも適用可能である。
【００４２】
【発明の効果】
本発明は以上のように、記憶部に圧力信号の所定値に対応する所定圧力をあらかじめ記憶させておき、検出される圧力信号の値が上述の所定圧力に至った際に、重負荷作業時にあっては再生操作が解除され、軽負荷作業時にあっては再生操作をおこなわせる構成にしてあるので、重負荷作業及び軽負荷作業のいずれか所望の作業に好適なアクチュエータの駆動制御を容易に実現させることができ、従来では困難であった重負荷作業、軽負荷作業双方の作業能率の向上を実現させることができる。
【図面の簡単な説明】
【図１】本発明の請求項１〜７に相当する油圧機械の油圧再生装置の一実施例を示す回路図である。
【図２】図１に示す実施例に備えられる制御装置の構成を示す図である。
【図３】図２に示す制御装置の記憶部及び演算部の構成を示す図である。
【図４】図１に示す実施例で得られる特性を示す図である。
【図５】従来の油圧機械の油圧再生装置を示す回路図である。
【符号の説明】
１ 油圧ポンプ
２ 油圧シリンダ（アクチュエータ）
２０ 方向切換弁
２１ チェック弁
２３ タンク側通路
２４ 連絡通路
２５ 可変絞り（流量制御手段）
２８ ポンプ側通路
２９ 圧力検出器（検出手段）
３０ タンク
４０ 電磁比例減圧弁（駆動手段）
４１ 作業モードスイッチ（指示装置）
４４ 制御装置
６１ 演算部
６２ 記憶部
７０ パイロット操作弁
１００ 関数関係
１０１ 関数関係[0001]
[Industrial applications]
The present invention relates to a hydraulic regeneration device provided in a hydraulic machine such as a hydraulic shovel and capable of regenerating and supplying return oil from an actuator to the actuator.
[0002]
[Prior art]
Japanese Patent Publication No. 4-59484 discloses a hydraulic regeneration device for a hydraulic machine of this type. FIG. 5 is a circuit diagram showing this prior art. As shown in FIG. 5, this prior art includes a hydraulic pump 1 and a pilot pump 1a, and an actuator driven by hydraulic oil discharged from the hydraulic pump 1, that is, a hydraulic cylinder 2 having a bottom chamber C and a rod chamber D. And a direction switching valve 3 for controlling the flow of the pressure oil supplied from the hydraulic pump 1 to the hydraulic cylinder 2 and having a left switching position 3a and a right switching position 3b.
[0003]
A left-side switching position 3a of the direction switching valve 3, which is a switching position for driving the hydraulic cylinder 2 in the extending direction, has a tank-side passage, that is, a discharge passage 6 connected to the tank, and a pump-side passage connected to the hydraulic pump 1. A passage, that is, a supply passage 5, a communication passage 10 that connects the supply passage 5 and the discharge passage 6, and is provided in the communication passage 10, and allows the supply of the pressure oil from the discharge passage 6 to the supply passage 5. Permitting means, that is, a check valve 7, flow rate controlling means for controlling the flow rate of pressure oil guided to the tank, that is, a merging switching device 8 that selectively shuts off the discharge passage 6, and a merging switching device 8 that communicates with the supply passage 5. Pressure detecting means for guiding a pressure signal for driving the pressure sensor, that is, a pressure detecting passage 9 is provided. Further, the driving means of the merging switching device 8 which supplies the pilot pressure of the pilot pump 1a to the merging switching device 8 as an external pressure signal Pc, that is, as a set pressure so as to oppose the pressure signal guided through the pressure detection passage 9 described above. That is, an external pressure signal generator 15 is provided.
[0004]
In the prior art configured as above, when the direction switching valve 3 is switched to the left switching position 3a, the pressure oil discharged from the hydraulic pump 1 is guided to the bottom chamber side C of the hydraulic cylinder 2 via the supply passage 5. The pressure oil flowing out of the rod-side chamber D of the hydraulic cylinder 2 is guided to the tank via the discharge passage 6. At this time, the pressure in the supply passage 5 is guided to the pressure detection passage 9, and when the pressure signal is lower than the external pressure signal Pc set by the external pressure signal generator 15, the merging switching device 8 controls the discharge passage 6. It is driven so as to be shut off, and the entire amount of return oil from the rod side chamber D of the hydraulic cylinder 2 is guided from the discharge passage 6 to the supply passage 5 via the check valve 7, and merges with the flow rate in the supply passage 5. Thereby, the operating speed of the hydraulic cylinder 2 can be increased.
[0005]
Further, when the load pressure of the hydraulic cylinder 2 increases, the pressure of the supply passage 5 increases, and the pressure signal guided to the pressure detection passage 9 becomes higher than the external pressure signal Pc set by the external pressure signal generator 15, The junction switching device 8 drives the discharge passage 6 to communicate, and the discharge passage 6 communicates with the tank. Therefore, the return oil from the rod side chamber D of the hydraulic cylinder 2 is returned to the tank without being joined to the supply passage 5. Thereby, the speed increase of the hydraulic cylinder 2 is suppressed, and the normal speed is maintained.
[0006]
As described above, in the prior art shown in FIG. 5, when the load pressure generated when the hydraulic cylinder 2 is extended is equal to or lower than the set pressure, the entire amount of the return oil from the rod-side chamber D of the hydraulic cylinder 2 regenerates into the bottom-side chamber C. Thus, the hydraulic cylinder 2 is increased in speed compared to the normal speed, and when the load pressure generated when the hydraulic cylinder 2 is extended is larger than the set pressure, the hydraulic cylinder 2 is maintained at the normal speed.
[0007]
[Problems to be solved by the invention]
Some hydraulic machines selectively perform a heavy load operation requiring a large load pressure and a light load operation requiring a relatively low load pressure and a high operation speed. For example, when the hydraulic machine is a hydraulic excavator, a single hydraulic excavator selectively performs a light-load work “topsoil stripping work” and a heavy-load work “groove excavation work”. Is often done. In this case, in the prior art shown in FIG. 5 described above, a large thrust is required in order to perform the “groove excavation work” that is a heavy load operation, and therefore, the set pressure, that is, the value of the external pressure signal Pc is set as low as possible. Thus, it is necessary to release the regeneration within a low load pressure. Conversely, a large thrust is not required in the light-load work “topsoil stripping work”, and it is preferable to set the value of the pressure signal Pc as high as possible in order to obtain a high working speed.
[0008]
Therefore, in the above-described conventional technology, when the value of the external pressure signal Pc is set low in advance in consideration of the “groove excavation work” that is a heavy load operation, when the “topsoil stripping operation” is performed, the operation speed, that is, The operating speed of the hydraulic cylinder 2 becomes slow, and the work efficiency of the "light soiling work", which is this light load work, is reduced. Conversely, if the value of the external pressure signal Pc is set high in advance in consideration of the light-load work “topsoil stripping work”, a large thrust cannot be obtained in the “groove excavation work” and this heavy-load work is performed. The work efficiency of "groove excavation work" will be reduced. As described above, in the related art, the value of the external pressure signal Pc must be uniquely determined in consideration of either the heavy load operation or the light load operation. However, it has been difficult to improve the working efficiency of both light-load work.
[0009]
Note that this may occur even during one continuous operation. For example, in consideration of "topsoil stripping work" in which a high working speed is required, when the value of the external pressure signal Pc is set high in advance and "topsoil stripping work" is performed, the bucket of the hydraulic shovel is In the case of hitting the hard ground, a large thrust cannot be obtained because the value of the external pressure signal Pc is set to be high, and the hydraulic cylinder 2 is stopped and the efficiency of work is reduced.
[0010]
The present invention has been made in view of the above-described circumstances in the related art, and an object of the present invention is to provide a hydraulic machine capable of selectively performing a heavy load operation and a light load operation through the operation of an actuator. An object of the present invention is to provide a hydraulic regeneration device for a hydraulic machine that can easily realize drive control of an actuator suitable for a desired operation of either a work or a light load work.
[0011]
[Means for Solving the Problems]
To achieve this object, the invention according to claim 1 of the present invention will be described below with reference to reference numerals used in the embodiments shown in FIGS.
[0012]
The present invention provides a hydraulic pump 1 and a tank 30, an actuator driven by hydraulic oil discharged from the hydraulic pump 1, for example, a hydraulic cylinder 2, and a flow of hydraulic oil supplied from the hydraulic pump 1 to the hydraulic cylinder 2. Directional control valve 20, a tank-side passage 23 connecting the hydraulic cylinder 2 to the tank 30, a flow control means for controlling the flow rate of pressure oil guided to the tank 30, for example, a variable throttle 25, A pump-side passage 28 connecting the pump 1 and the hydraulic cylinder 2, a communication passage 24 connecting the pump-side passage 28 and the tank-side passage 23, and a pressure in the tank-side passage 23 provided in the communication passage 24. When the pressure is higher than the pressure in the pump-side passage 28, the check valve 21 that allows the supply of the pressure oil from the tank-side passage 23 to the pump-side passage 28, and a hydraulic system Detecting means for detecting the pressure of the pressure oil supplied to the hydraulic pump 2, for example, a pressure detector 29 for detecting the discharge pressure of the hydraulic pump 1, and driving means for driving the variable throttle 25, for example, an electromagnetic proportional pressure reducing valve 40; And a regenerating operation for joining the return oil from the hydraulic cylinder 2 to the pump-side passage 28 via the communication passage 24 as a basic structure.
[0013]
In addition to this basic configuration, the present invention provides a control device 44 which receives a pressure signal PD from the above-described pressure detector 29 and outputs an operation signal is corresponding to the pressure signal PD to the above-mentioned electromagnetic proportional pressure reducing valve 40. The control device 44 converts a functional relationship between the pressure signal PD and a target value corresponding to the operation signal is, for example, a target current i, into a functional relationship 101 corresponding to a predetermined heavy load operation, and a predetermined relationship. Based on the storage unit 62 set in advance as a plurality of functional relationships 100 corresponding to the light load operation, and the pressure signals PD and the functional relationships 101 and 100 stored in the storage unit 62, the corresponding target current i And a calculation unit 61 that calculatesA predetermined pressure (Pd in FIG. 3) corresponding to a predetermined value of the pressure signal PD is stored in the storage unit 62. 2 ) Is stored in advance, and the function relation 101 corresponding to the predetermined heavy load operation and the function relation 100 corresponding to the predetermined light load operation stored in the storage unit 62 are changed by the value of the pressure signal PD. The predetermined pressure (Pd in FIG. 3) stored in the storage unit 62 2 ), The function relation 101 corresponding to the predetermined heavy load operation is set to be a function relation for canceling the reproduction operation, and the function relation 100 corresponding to the predetermined light load operation is set to the reproduction operation. It is set so that the function relations can be performed.
[0014]
An instruction device, such as an operation mode switch 41, capable of outputting an instruction signal MS corresponding to each of the predetermined heavy load operation and the predetermined light load operation to the control device 44 is provided.
[0015]
Then, in accordance with the instruction signal MS output from the work mode switch 41, the calculation unit 61 of the control device 44 determines a functional relationship 101 corresponding to the predetermined heavy load work stored in the storage unit 62, The calculation for obtaining the target current i is performed based on the relevant functional relationship among the functional relationships 100 corresponding to the light load work.
[0016]
[Action]
Since the invention according to claim 1 of the present invention has the above-described configuration, when performing a heavy load operation such as “groove excavation operation” in a hydraulic excavator, for example, the operation mode switch 41 serving as an instruction device is set to the operation mode switch 41. It is sufficient to output the instruction signal MS corresponding to the heavy load operation to perform the switching operation of the direction switching valve 20. In response to the instruction signal MS output from the work mode switch 41, the calculation unit 61 of the control device 44 determines the function relation 101 corresponding to the heavy load work shown in FIG. An operation for obtaining the target current i is performed based on the pressure signal PD output from the control unit 29 and the pressure signal PD.
[0017]
Here, the functional relationship 101 corresponding to the heavy load operation is such that when the value of the pressure signal PD is relatively small, the variable relationship 25 as the flow control means can be fully opened, that is, the value of the pressure signal PD Is relatively small (Pd in FIG. 3)2) Is a functional relationship that can sometimes cancel the playback operation.
[0018]
The drive signal is corresponding to the target current i based on such a functional relationship 101 is output from the control device 44 to the electromagnetic proportional pressure reducing valve 40 which is a drive means. Thereby, the electromagnetic proportional pressure reducing valve 40 is driven, and the pressure signal PD of the variable throttle 25 is relatively small (Pd in FIG. 3).2) At the time of full opening, and operates so as to allow the entire amount to pass through the tank side passage 23. Thus, the reproduction operation is released. Therefore, the pressure oil of the hydraulic pump 1 is supplied to the hydraulic cylinder 2 as an actuator via the pump side passage 28 and the direction switching valve 20, and the return oil of the hydraulic cylinder 2 is supplied via the direction switching valve 20 and the tank side passage 23. The whole amount can be returned to the tank 30. As a result, a large thrust is obtained, and it is possible to cope with heavy load work.
[0019]
For example, when performing a light load operation such as “top soil stripping operation” in a hydraulic excavator, the operation mode switch 41 as an instruction device is operated to output an instruction signal MS corresponding to the light load operation, and The switching operation of the switching valve 20 may be performed. In response to the instruction signal MS output from the work mode switch 41, the calculation unit 61 of the control device 44 stores the functional relationship 100 corresponding to the light load work shown in FIG. Is calculated on the basis of the pressure signal PD output from the controller and the target signal i.
[0020]
Here, the functional relationship 100 corresponding to the light load operation is performed while the value of the pressure signal PD is relatively small (for example, Pd in FIG. 3).2) Is a functional relationship such that the variable throttle valve 25 as the flow control means is not fully opened, that is, while the value of the pressure signal PD is relatively small (for example, Pd in FIG. 3).2) Is a functional relationship that enables the reproduction operation.
[0021]
The drive signal is corresponding to the target current i based on such a functional relationship 100 is output from the control device 44 to the electromagnetic proportional pressure reducing valve 40 as the drive means. Accordingly, the electromagnetic proportional pressure reducing valve 40 is driven, and the variable throttle 25 is operated when the value of the pressure signal PD is small (for example, Pd in FIG. 3).2) Does not fully open, but restricts the flow of oil from the tank side passage 23 into the tank 30. Along with this, the pressure in the tank-side passage 23 rises, and a regeneration operation is enabled. When the pressure in the tank side passage 23 becomes larger than the pressure in the pump side passage 28, the pressure oil in the tank side passage 23 joins the pump side passage 28 via the communication passage 24 and the check valve 21. Therefore, the combined pressure oil of the return oil of the hydraulic cylinder 2 and the pressure oil discharged from the hydraulic pump 1 is supplied to the hydraulic cylinder 2. Thus, the hydraulic cylinder 2 can be driven at a higher operating speed than the normal speed which is the operating speed of the hydraulic cylinder 2 during the heavy-load operation described above, and can be adapted to a light-load operation.
[0022]
【Example】
Hereinafter, an embodiment of a hydraulic regeneration device for a hydraulic machine according to the present invention will be described with reference to the drawings. 1 to 4 show an embodiment of a hydraulic regenerator for a hydraulic machine according to claims 1 to 7 of the present invention. FIG. 1 is a circuit diagram showing an overall configuration, and FIG. 2 is an embodiment shown in FIG. FIG. 3 is a diagram showing a configuration of a storage unit and a calculation unit of the control device shown in FIG. 2, and FIG. 4 is a diagram showing characteristics obtained in the embodiment shown in FIG. .
[0023]
This embodiment is applied to, for example, a hydraulic excavator. As shown in FIG. 1, an engine 43, a hydraulic pump 1 driven by the engine 43, a tank 30, and pressure oil discharged from the hydraulic pump 1 are used. An actuator such as a boom cylinder, an arm cylinder, or a bucket cylinder to be driven, that is, a hydraulic cylinder 2, and a direction switching valve 20 for controlling the flow rate of hydraulic oil supplied from the hydraulic pump 1 to the hydraulic cylinder 2 are provided. The direction switching valve 20 has a neutral position, a switching position 20a at which hydraulic oil can be supplied to the bottom chamber C of the hydraulic cylinder 2, and a switching position 20b at which hydraulic oil can be supplied to the rod chamber D of the hydraulic cylinder 2. By operating the operation lever 71 of the pilot valve 70, the direction switching valve 20 is switched to one of the switching positions 20a and 20b by selectively outputting pilot pressures Pa and Pb.
[0024]
A tank-side passage 23 that connects the hydraulic cylinder 2 to the tank 30; and a flow control unit that is disposed in the tank-side passage 23 and that controls the flow rate of pressure oil guided to the tank 30, such as a hydraulically operated variable throttle. 25. The variable aperture 25 has a communication position 25a and an aperture position 25b.
[0025]
Further, a pump-side passage 28 that connects the hydraulic pump 1 and the hydraulic cylinder 2, a communication passage 24 that connects the pump-side passage 28 and the tank-side passage 23, and a tank-side passage 23 that is provided in the communication passage 24. When the internal pressure is higher than the pressure in the pump side passage 28, the supply of the pressure oil from the tank side passage 23 to the pump side passage 28 is allowed, and the pressure oil from the pump side passage 28 to the tank side passage 23 is allowed. A check valve 21 for blocking the flow ofPump side passage 28And a check valve 22 that allows the flow of pressure oil from the hydraulic pump 1 toward the direction switching valve 20 and prevents the flow of pressure oil from the direction switching valve 20 toward the direction of the hydraulic pump 1.
[0026]
Further, a detecting means for detecting the pressure of the pressure oil supplied to the hydraulic cylinder 2, for example, the pressure detector 29 for detecting the discharge pressure Pd of the hydraulic pump 1 and outputting a pressure signal, that is, a pump discharge pressure signal PD, A drive means for driving the variable throttle 25, for example, an electromagnetic proportional pressure reducing valve 40 for outputting a pilot pressure Pi to the pilot chamber of the variable throttle 25 is provided.
[0027]
In particular, in the present embodiment, a control device that inputs a pump discharge pressure signal PD output from the pressure detector 29 and outputs an operation signal is corresponding to the pump discharge pressure signal PD to the above-described electromagnetic proportional pressure reducing valve 40 44, and an instruction device for instructing one of the heavy load operation and the light load operation, for example, an operation mode switch 41 that outputs an instruction signal MS corresponding to the selected operation mode.
[0028]
As shown in FIG. 2, the control device 44 includes a pump discharge pressure signal PD output from the pressure detector 29 and an input unit 60 that inputs an instruction signal MS output from the work mode switch 41. A plurality of functional relationships between the pump discharge pressure signal PD and a target value corresponding to the operation signal is for operating the electromagnetic proportional pressure reducing valve 40, for example, a target current i, are set in advance corresponding to each of the heavy load operation and the light load operation. A storage unit 62 for calculating the target current i for driving the electromagnetic proportional pressure reducing valve 40; and an operating signal is corresponding to the target current i calculated by the arithmetic unit 61. And an output unit 63 that outputs to the valve 40.
[0029]
In the storage unit 62 of the above-described control device 44, for example, a functional relationship 100 corresponding to light load work and a functional relationship 101 corresponding to heavy load work shown in FIG. 3 are set. Among them, the functional relationship 101 corresponding to the heavy load operation is such that the pump discharge pressure signal PD has a predetermined low first set pressure Pd.1Constant target current i up to1And the pump discharge pressure signal PD becomes the first set pressure Pd1Beyond the second set pressure Pd2Until i0<I <i1, And the pump discharge pressure signal PD becomes the second set pressure Pd2When it becomes the above, the current value i0It is a functional relationship that outputs a target current i of = 0. Further, the functional relationship 100 corresponding to the light load operation is such that the pump discharge pressure signal PD is equal to the predetermined low first set pressure Pd described above.1Constant target current i up to1Is output, and the pump discharge pressure signal Pd is changed to the second set pressure Pd described above.2Set pressure Pd greater than3Until the target current i (i decreases in accordance with the increase of the pump discharge pressure signal PD)0<I <i1), And the pump discharge pressure signal PD becomes the third set pressure Pd.3If it is above, i0It is a functional relationship that outputs a target current i of = 0. That is, the gain of the functional relationship 101 corresponding to the heavy load operation is set to be larger in advance than the gain of the functional relationship 100 corresponding to the light load operation.
[0030]
In addition, in accordance with the instruction signal MS output from the work mode switch 41, the arithmetic unit 61 of the control device 44 described above stores the functional relationship 101 corresponding to the above-described heavy load work stored in the storage unit 62, An operation for obtaining the target current i is performed based on the corresponding functional relationship among the functional relationships 100 corresponding to the work and the pump discharge pressure signal PD output from the pressure detector 29.
[0031]
The operation of the embodiment configured as described above is as follows.
For example, if a heavy load operation is selected by the operation mode switch 41 shown in FIG. 1 in consideration of the “groove excavation operation”, an instruction signal MS corresponding to the heavy load operation is transmitted from the operation mode switch 41 to FIGS. The function relation 101 corresponding to the heavy load work is selected from the function relations 100 and 101 stored in the storage unit 62 of the control apparatus 44 by being output to the input unit 60 of the control apparatus 44 shown in FIG. The operation unit 61 operates the electromagnetic proportional pressure reducing valve 40 shown in FIG. 1 based on the functional relationship 101 corresponding to the heavy load operation and the pump discharge pressure signal PD output from the pressure detector 29. The calculation for obtaining the target value of the signal is, that is, the target current i is performed.
[0032]
In this state, when the operation lever 71 of the pilot valve 70 is operated, for example, to the A side in FIG. 1, a pilot pressure Pa is generated, and this pilot pressure Pa is transmitted to the pilot chamber located on the left side of the direction switching valve 20 in FIG. Then, the direction switching valve 20 is switched to the switching position 20a. Thereby, the pressure oil discharged from the hydraulic pump 1 is supplied to the bottom side chamber C of the hydraulic cylinder 2 through the pump side passage 28, the check valve 22, and the switching position 20a of the direction switching valve 20, and is returned from the rod side chamber D. The oil is returned to the tank 30 via the switching position 20a of the direction switching valve 20, the tank side passage 23, and the variable throttle 25.
[0033]
At this time, the pump discharge pressure signal PD detected by the pressure detector 29 is the first set pressure Pd of the functional relationship 101 stored in the storage unit 62 shown in FIG.1While the current is lower than the predetermined target current (i = i)1) Is obtained, and this target current (i = i1) (Is = i1) Is output from the output unit 63 of the control device 44 to the drive unit of the electromagnetic proportional pressure reducing valve 40. As a result, the pilot pressure pi output from the electromagnetic proportional pressure reducing valve 40 is minimized, and the variable throttle 25 is given a maximum throttle amount shown in FIG. And a pressure is generated in the tank-side passage 23 in accordance with the throttle amount of the variable throttle 25. When the pressure in the tank side passage 23 becomes equal to or higher than the pressure in the pump side passage 28, part of the return oil from the rod side chamber D of the hydraulic cylinder 2 is transferred to the pump side through the communication passage 24 and the check valve 21. An operation is performed in which the return oil flows into the passage 28 and joins the pressure oil discharged from the hydraulic pump 1 and is supplied to the bottom chamber C of the hydraulic cylinder 2. Accordingly, the flow rate flowing into the bottom chamber C of the hydraulic cylinder 2 is increased by the maximum regeneration flow rate shown in FIG. 4B flowing from the communication passage 24, and the operating speed of the hydraulic cylinder 2 is increased accordingly. be able to.
[0034]
In such a state, when the bucket of the hydraulic shovel performs the “groove excavation work” in which the bucket of the hydraulic shovel becomes difficult to sediment, and the load applied to the hydraulic cylinder 2 increases, the discharge pressure Pd of the hydraulic pump 1 increases and the pressure detector 29 The value of the pump discharge pressure signal PD output from the controller also increases. The value of the pump discharge pressure signal PD is the first set pressure Pd of the functional relationship 101 in FIG.1And the second set pressure Pd2, The target current i obtained by the calculation unit 61 of the control device 44 is i0<I <i1And the operation signal is output from the output unit 63 of the control device 44 is also i0<Is = i <i1, The value of the pilot pressure Pi output from the electromagnetic proportional pressure reducing valve 40 increases, and the variable throttle 25 changes its throttle amount to a small amount as shown in FIG. That is, it is driven so as to change from a slightly closed state to an open direction, the amount of oil returned to the tank 30 increases, and the regeneration flow rate gradually decreases as shown in FIG. 4B. That is, although the operating speed of the hydraulic cylinder 2 is slightly lower than before, a state in which a larger thrust can be obtained.
[0035]
Further, the value of the pump discharge pressure signal PD is the second set pressure Pd of the functional relationship 101 in FIG.2As described above, the target current i obtained by the calculation unit 61 of the control device 44 becomes i = i0And the operation signal is output from the output unit 63 is is = i = i0As a result, the value of the pilot pressure Pi output from the electromagnetic proportional pressure reducing valve 40 becomes the maximum, and the variable throttle 25 moves to the fully opened switching position 25a where the throttle amount is 0 as shown in FIG. Is switched. As a result, as shown in FIG. 4B, the regeneration flow rate becomes zero, and the regeneration is released, in which the entire amount of the tank side passage 23 is returned to the tank 30. As a result, the pressure in the rod side chamber D of the hydraulic cylinder 2 is reduced. Therefore, the thrust of the hydraulic cylinder 2 increases, and the excavation force is rapidly increased, so that a “groove excavation operation” as a desired heavy load operation can be performed.
[0036]
For example, if the light load work is selected by the work mode switch 41 in consideration of the "top soil stripping work" or the "leveling work" for leveling the ground, the work mode switch 41 responds to the light load work. Is output to the input unit 60 of the control device 44. As a result, the functional relation 100 corresponding to the light-load work is selected from the functional relations 100 and 101 stored in the storage unit 62 of the control device 44, and the storage unit 61 of the control device 44 corresponds to the light-load work. Based on the functional relationship 100 and the pump discharge pressure signal PD output from the pressure detector 29, an operation for obtaining the target current i is performed. In this state, when the operation lever 71 is operated and the direction switching valve 20 is switched to, for example, the switching position 20a, pressure oil is supplied to the bottom chamber C of the hydraulic cylinder 2 as described above, and the hydraulic cylinder 2 Operates in the direction of extension.
[0037]
At this time, the pump discharge pressure signal PD detected by the pressure detector 29 is equal to the first set pressure Pd.1As described above, the variable throttle 25 is held at the throttle position 25b capable of providing the maximum throttle amount shown in FIG. 4A, and the pressure corresponding to the throttle amount of the variable throttle 25 is stored in the tank-side passage 23 as described above. Can be generated, the maximum regeneration flow rate shown in FIG. 4B is secured, and a desired regeneration operation can be performed. That is, the return oil of the hydraulic cylinder 2 and the pressure oil discharged from the hydraulic pump 1 can be combined and supplied to the bottom side chamber C of the hydraulic cylinder 2, and the operating speed of the hydraulic cylinder 2 is increased to achieve the desired “top soil” Light-duty work such as "patch work" can be performed. Note that the load pressure slightly increases due to the resistance of soil and the like hitting the tip of a bucket (not shown), and the value of the pump discharge pressure signal PD output from the pressure detector 29 temporarily changes to the second set pressure Pd.2Even when the gain becomes smaller, the gain of the functional relationship 100 related to the light load work is set to be smaller in advance than the gain of the functional relationship 101 related to the heavy load work described above. The current i is i0<I <i1, And the operation signal is output from the output unit 63 is also i0<Is = i <i1Accordingly, the pilot pressure Pi output from the electromagnetic proportional pressure reducing valve 40 becomes minimum <Pi <maximum, and the variable throttle 25 holds the throttle amount located on the characteristic line of FIG. Maintained in state. Therefore, although the regeneration flow rate slightly decreases as shown in FIG. 4B, the regeneration operation can be continued.
[0038]
Then, when a situation corresponding to a heavy load operation occurs during a light load operation such as “topsoil stripping operation”, for example, when a tip of a bucket (not shown) has entered the hard ground, etc. Since the discharge pressure pd of the hydraulic pump 1 increases with an increase in the load pressure, the value of the pump discharge pressure signal PD detected by the pressure detector 29 increases, and for example, the third set pressure Pd3It can be more than this. When such a situation occurs, i = i0, And the operation signal is output from the output unit 63 is is = i = i0The pilot pressure Pi output from the electromagnetic proportional pressure reducing valve 40 becomes maximum, and the variable throttle 25 is switched to the communication position 25a where the throttle amount is almost 0 as shown in FIG. The regeneration release state is reached in which the entire amount of 23 is returned to the tank 30. In this state, as shown in FIG. 4 (b), the regeneration flow rate is lost, and the rod side chamber D of the hydraulic cylinder 2 communicates with the tank 30, so that a large thrust of the hydraulic cylinder 2 can be secured as described above. By moving the bucket into the hard ground, it is possible to perform an operation of escaping from the hard ground. That is, a light-load work such as a “topsoil stripping work” can be performed continuously without stopping the work due to the stop of the hydraulic cylinder 2.
[0039]
In the embodiment configured as described above, according to the functional relationships 100 and 101 of the control device 44 selected by the operation mode switch 41 as described above, one hydraulic excavator can perform a light load operation and a heavy load operation. It is possible to perform drive control of the hydraulic cylinder 2 suitable for both of them, and thereby it is possible to improve the work efficiency of both light load work and heavy load work.
[0040]
In the above embodiment, the pressure detector 29 for detecting the discharge pressure Pd of the hydraulic pump 1 is provided, and the regeneration operation and the regeneration release operation are performed based on the pump discharge pressure signal PD output from the pressure detector 29. However, the present invention is not limited to this. For example, a pressure detector for detecting a load pressure is provided in a main line located between the directional control valve 20 and the hydraulic cylinder 2 and the pressure detector is provided. The regeneration operation and the regeneration release operation may be performed based on the pressure signal output from the.
[0041]
Further, in the above-described embodiment, the hydraulic cylinder 2 is described as an example of the actuator, but a configuration in which a hydraulic motor is provided instead of the hydraulic cylinder 2 may be used. In the above description, a hydraulic excavator has been described as a hydraulic machine. However, the present invention is not limited to such a hydraulic excavator, and is applicable to a hydraulically operated crane and the like.
[0042]
【The invention's effect】
As described above, the present inventionIn the storage unit, a predetermined pressure corresponding to a predetermined value of the pressure signal is stored in advance, and when the value of the detected pressure signal reaches the above-described predetermined pressure, the regeneration operation is released during heavy load work. And perform regenerating operations during light load work.ConstitutionToTherefore, it is possible to easily realize the drive control of the actuator suitable for any one of the heavy load work and the light load work. The efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing one embodiment of a hydraulic regeneration device for a hydraulic machine according to claims 1 to 7 of the present invention.
FIG. 2 is a diagram showing a configuration of a control device provided in the embodiment shown in FIG.
FIG. 3 is a diagram showing a configuration of a storage unit and a calculation unit of the control device shown in FIG.
FIG. 4 is a diagram showing characteristics obtained in the embodiment shown in FIG. 1;
FIG. 5 is a circuit diagram showing a conventional hydraulic regeneration device for a hydraulic machine.
[Explanation of symbols]
1 hydraulic pump
2 Hydraulic cylinder (actuator)
20 Directional switching valve
21 Check valve
23 Tank side passage
24 Access passage
25 Variable throttle (flow control means)
28 Pump side passage
29 Pressure detector (detection means)
30 tanks
40 Electromagnetic proportional pressure reducing valve (drive means)
41 Work mode switch (indicator)
44 Control device
61 Operation unit
62 Memory
70 Pilot operated valve
100 Function relations
101 Function Relationship

Claims (6)

油圧ポンプ及びタンクと、
上記油圧ポンプから吐出される圧油によって駆動するアクチュエータと、
上記油圧ポンプから上記アクチュエータに供給される圧油の流れを制御する方向切換弁と、
上記アクチュエータと上記タンクとを連絡するタンク側通路と、
上記タンクに導かれる圧油の流量を制御する流量制御手段と、
上記油圧ポンプと上記アクチュエータとを連絡するポンプ側通路と、
このポンプ側通路と上記タンク側通路とを連絡する連絡通路と、
この連絡通路に設けられ、上記タンク側通路内の圧力が上記ポンプ側通路内の圧力よりも高いとき、タンク側通路からポンプ側通路への圧油の供給を許容させるチェック弁と、
上記アクチュエータに供給される圧油の圧力を検出する検出手段と、
上記流量制御手段を駆動する駆動手段とを備え、
上記連絡通路を介して上記アクチュエータからの戻り油を上記ポンプ側通路に合流させる再生操作が可能な油圧機械の油圧再生装置において、
上記検出手段からの圧力信号を入力し、その圧力信号に応じた作動信号を上記駆動手段に出力する制御装置を備え、
この制御装置が、上記圧力信号と、上記作動信号に対応する目標値との関数関係を、所定の重負荷作業及び所定の軽負荷作業のそれぞれに対応してあらかじめ複数設定する記憶部と、上記圧力信号と上記記憶部に記憶された関数関係とに基づいて該当する上記目標値を演算する演算部とを有し、
上記所定の重負荷作業及び所定の軽負荷作業のそれぞれに相当する指示信号を上記制御装置に出力可能な指示装置を備え、
上記制御装置の演算部は、上記指示装置から出力される指示信号に応じて、上記記憶部に記憶されている所定の重負荷作業に対応する関数関係、及び所定の軽負荷作業に対応する関数関係のうちの該当する関数関係に基づいて目標値を求める演算をおこなうようになっており、
上記記憶部に上記圧力信号の所定値に対応する所定圧力をあらかじめ記憶させるとともに、
上記記憶部に記憶される上記所定の重負荷作業に対応する関数関係、及び上記所定の軽負荷作業に対応する関数関係を、上記圧力信号の値が上記記憶部に記憶される上記所定圧力に至った際に、上記所定の重負荷作業に対応する関数関係は再生操作を解除する関数関係となるように設定し、上記所定の軽負荷作業に対応する関数関係は再生操作をおこなわせる関数関係となるように設定したことを特徴とする油圧機械の油圧再生装置。A hydraulic pump and a tank,
An actuator driven by pressure oil discharged from the hydraulic pump,
A direction switching valve for controlling the flow of pressure oil supplied from the hydraulic pump to the actuator,
A tank-side passage communicating the actuator with the tank,
Flow rate control means for controlling the flow rate of pressure oil guided to the tank,
A pump-side passage communicating the hydraulic pump and the actuator,
A communication passage connecting the pump side passage and the tank side passage,
A check valve that is provided in the communication passage and that allows supply of pressure oil from the tank-side passage to the pump-side passage when the pressure in the tank-side passage is higher than the pressure in the pump-side passage;
Detecting means for detecting the pressure of the pressure oil supplied to the actuator,
Driving means for driving the flow rate control means,
In a hydraulic regeneration device for a hydraulic machine capable of performing a regeneration operation for joining return oil from the actuator to the pump-side passage through the communication passage,
A control device that receives a pressure signal from the detection unit and outputs an operation signal corresponding to the pressure signal to the driving unit,
A storage unit that sets a plurality of functional relationships between the pressure signal and a target value corresponding to the operation signal in advance corresponding to each of a predetermined heavy load operation and a predetermined light load operation; possess a calculator for calculating the target value appropriate based on the functional relationship stored in the pressure signal and the storage unit,
An instruction device capable of outputting an instruction signal corresponding to each of the predetermined heavy load operation and the predetermined light load operation to the control device,
The arithmetic unit of the control device is configured to perform a function relationship corresponding to a predetermined heavy load operation and a function corresponding to a predetermined light load operation stored in the storage unit in response to an instruction signal output from the instruction device. The calculation for obtaining the target value is performed based on the corresponding functional relationship among the relationships ,
A predetermined pressure corresponding to a predetermined value of the pressure signal is stored in the storage unit in advance,
The functional relationship corresponding to the predetermined heavy-load work stored in the storage unit, and the functional relationship corresponding to the predetermined light-load work, the value of the pressure signal to the predetermined pressure stored in the storage unit At this time, the functional relationship corresponding to the predetermined heavy load operation is set to be a functional relationship for canceling the regeneration operation, and the functional relationship corresponding to the predetermined light load operation is a functional relationship for performing the regeneration operation. A hydraulic regeneration device for a hydraulic machine, wherein the hydraulic regeneration device is set so that: 上記指示装置が、作業モードスイッチであることを特徴とする請求項１記載の油圧機械の油圧再生装置。The hydraulic regeneration device for a hydraulic machine according to claim 1, wherein the instruction device is a work mode switch. 上記検出手段が、上記油圧ポンプの吐出圧を検出する圧力検出器、及び上記アクチュエータの負荷圧を検出する圧力検出器の一方であることを特徴とする請求項１記載の油圧機械の油圧再生装置。2. The hydraulic regeneration device for a hydraulic machine according to claim 1, wherein said detection means is one of a pressure detector for detecting a discharge pressure of said hydraulic pump and a pressure detector for detecting a load pressure of said actuator. . 上記流量制御手段が、可変絞りであることを特徴とする請求項１記載の油圧機械の油圧再生装置。2. The hydraulic regeneration device for a hydraulic machine according to claim 1, wherein said flow control means is a variable throttle. 上記駆動手段が、電磁比例減圧弁であることを特徴とする請求項１記載の油圧機械の油圧再生装置。2. The hydraulic regeneration device for a hydraulic machine according to claim 1, wherein said driving means is an electromagnetic proportional pressure reducing valve. 上記所定圧力を第２の所定圧力とすると共に上記記憶部に、
上記第２の所定圧力よりも低い圧力であって、上記所定の重負荷作業及び上記所定の軽負荷作業で再生操作をおこなわせる第１の所定圧力と、上記第２の所定圧力よりも高い圧力であって、上記所定の重負荷作業及び上記所定の軽負荷作業のときに再生操作を解除させる第３の所定圧力とをあらかじめ記憶させることを特徴とする請求項１記載の油圧機械の油圧再生装置。 The predetermined pressure is set to a second predetermined pressure, and the storage unit
A pressure lower than the second predetermined pressure, a first predetermined pressure for performing a regeneration operation in the predetermined heavy load operation and the predetermined light load operation, and a pressure higher than the second predetermined pressure The hydraulic regeneration of the hydraulic machine according to claim 1, wherein a third predetermined pressure for releasing the regeneration operation during the predetermined heavy load operation and the predetermined light load operation is stored in advance. apparatus.
JP2420795A 1995-02-13 1995-02-13 Hydraulic regenerator of hydraulic machine Expired - Fee Related JP3594680B2 (en)

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