【０００１】
【発明の属する技術分野】
本発明は、射出成形機を複数台設置し、該射出成形機毎にこれの駆動シリンダ及び該駆動シリンダへの作動流体の供給、遮断を制御する電磁弁を設けてなる射出成形機の水圧駆動装置に関する。
【０００２】
【従来の技術】
図３には、例えば特開２００１−１５０１２０号に開示されている射出成形機及びその駆動装置の従来の一例が示されている。
図において、０１０は射出成形機、０１８は該射出成形機０１０を往復駆動する駆動シリンダであり、計量モータによりスクリュー０１５が回転駆動され、ホッパ０１２から供給されるチップ０１３をシリンダ０１１の先端のノズル０１６に向けて送り出す。
該スクリュー０１５の回転数に対応して計量されたチップ０１３は、シリンダ０１１の中を移動する際にシリンダ０１１外周に設置されたヒータ０１７により加熱され溶融チップ（溶融体）になる。
【０００３】
他方、油圧源０２２からの加圧された作動油は逆止弁を通ってアキュムレータ０２１に送り込まれ貯留されている。０２４は方向切換流量調整弁、０２５はＡＣＣ切換弁で、配管０２７、０２８に対する流れ方向が前記方向切換流量調整弁０２４の左側矢印のように設定され、前記ＡＣＣ切換弁０２５がこれの左側矢印のように設定されて開かれると、前記アキュムレータ０２１に貯留されていた作動油が配管０２７、０２８を経て前記駆動シリンダ０１８の油室０１８ａに送り込まれる。
【０００４】
これにより、射出用のピストン０１８はノズル０１６の方向に押圧され、反対側の油室０１８ｂ内の作動油は配管０２８を経て容器に排出され、かかる過程での使用油を補うために、前記油圧源０２２によってアキュムレータ０２１に作動油が貯留される。
前記ピストン０１８が油室０１８ａ内の作動油によって押圧されることにより、シリンダ０１１の先端部にある溶融チップ０１３が金型内に射出される。尚、０２９は油圧源切換弁である。
【０００５】
【発明が解決しようとする課題】
図３に示されるような、油圧駆動の射出成形機においては、１台の射出成形機０１０及び駆動シリンダ０１８毎に油圧源０２２を含む１セットの油圧供給システムを装備している。
このため、複数台の射出成形機０１０及び駆動シリンダ０１８を設置する際には、これに対応する複数セットの油圧供給システムを装備することを要し、装置の設置スペースが増大するとともに、機器数が多くなり装置コストが高くなる。
また、かかる油圧駆動射出成形機にあっては、射出成形機のホッパ０１２からシリンダ０１１内にチップ０１３を充填している間も、油圧源０２２を含む油圧システムを、駆動シリンダ０１８の油圧を所要油圧に常時保持して運転する必要があることから、射出成形機システムの稼働率が低くならざるを得ない。
【０００６】
かかる問題点に対処する手段の１つとして、特開平８−３３２６５９号の発明が提案されている。
かかる発明においては、複数台の射出成形機及び駆動シリンダ毎に電磁切換弁を設け、モータにより駆動される油圧ポンプを備えた１セットの油圧システムからの作動油路を前記各電磁切換弁に接続し、該作動油路には油圧脈動低減用のアキュムレータを設けている。
そして、かかる発明においては、前記アキュムレータ内の圧力を検出する圧力センサを設けて、この圧力検出値が該圧力センサ自体に設定された下限圧力以下のときには油圧源側電磁弁により油圧源の作動油をアキュムレータに送り込んで該作動油路の圧力を上げ、前記圧力検出値が該圧力センサ自体に設定された上限圧力を超えるときには油圧源側電磁弁により油圧源の作動油をアキュムレータに送り込んで該作動油路の圧力を上げるように構成されている。
【０００７】
しかしながら、かかる発明においては、作動流体が油（油圧）であるため（図３の射出成形機駆動シリンダも同様）、油漏れを生じた際の整備が煩雑で、整備性が良好でなく、またオイルミストで周囲を汚し易く、環境面でも課題がある。
また、かかる発明にあっては、アキュムレータ及び作動油路の圧力を検出しこの検出信号により油圧源側の作動を制御して、アキュムレータ及び作動油路の圧力を常時許容上限圧力と下限圧力との間の許容圧力に維持せしめているにとどまり、複数台の射出成形機及び駆動シリンダ毎に電磁切換弁を適切なタイミングで個別に開閉制御する手段は備えておらず、従って、前記各射出成形機は前記圧力センサとアキュムレータと油圧源側電磁弁とにより調整された作動圧力で常時運転されることとなる。
【０００８】
このため、かかる従来技術にあっては、複数台の射出成形機のうちの一部がホッパのチップをシリンダ内に充填し、実質的に駆動動力が不要な機械があるにも拘わらず、油圧供給系から複数台の射出成形機の全てに必要作動圧力で常時作動油が供給されこととなるため、油圧供給系に無駄な動力が付与されることとなり、エネルギー損失が大きくなって、装置の効率が低い。
また、前記のように、チップをシリンダ内に充填中の射出成形機の駆動シリンダにも前記作動圧力の作動油が常時供給されるため、作動油の漏れ等の作動油系の不具合が発生し易く、システムの信頼性及び整備性にも課題がある。
【０００９】
本発明はかかる従来技術の課題に鑑み、複数台の射出成形機及び駆動シリンダを備えた射出成形機システムにおいて、駆動エネルギー損失を低減してシステムの稼動効率を向上し、かつ良好なシステム周りの環境を維持し、故障等の発生が少なく信頼性、整備性を向上した射出成形機の水圧駆動装置を提供することを目的とする。
【００１０】
【課題を解決するための手段】
本発明はかかる課題を解決するため、請求項１記載の発明として、シリンダと該シリンダ内に往復動自在に嵌合されたピストンとを備えた駆動シリンダにより射出スクリューを往復動せしめるように構成された射出成形機を複数台設置し、該射出成形機毎に前記駆動シリンダ及び該駆動シリンダへの作動流体の供給、遮断を制御する電磁弁を設けてなる射出成形機の駆動装置において、前記駆動シリンダを前記作動流体として水を用いた水圧シリンダに構成するとともに可変速モータにより駆動される単一の水圧ポンプから作動流体通路を通して前記各電磁弁及び各水圧シリンダに作動流体を供給する水圧供給手段を備えてなることを特徴とする射出成形機の水圧駆動装置を提案する。
【００１１】
請求項２記載の発明は、請求項１に加えて、前記作動流体通路に設けられたアキュムレータと、作動流体通路に連通される該アキュムレータ内あるいは前記作動流体通路の作動流体圧力を検出する圧力検出器と、該圧力検出器からの前記作動流体圧力の検出信号が入力され該作動流体圧力の検出値に基づき前記駆動シリンダのうちの水圧作動中の駆動シリンダにおける作動流体圧力が前記射出成形機の必要駆動圧力になるように前記電磁弁を選択的に開閉制御する制御装置とを備えてなる。
【００１２】
そして、好ましくは請求項２に加えて、請求項３記載のように、前記制御装置は、前記作動流体圧力の検出値に基づき前記可変速モータの回転数を制御する手段を備えるのがよい。
【００１３】
かかる発明によれば、射出成形機システムにおいて、該システムの作動流体として無公害で投棄性の良好な水を用いた水圧駆動システムを備えたので、従来の油圧による駆動システムのように、オイルミストの飛散や油漏れが生じた際における機器周辺の汚染等の問題がなく、環境衛生面において好適なシステムが得られる。
また、水圧漏れが生じた場合にも、水は投棄性が良好であり周辺の汚染がないので修理や整備が簡単にでき、従来の油圧駆動システムに比べて整備性が向上する。
【００１４】
また、射出成形機の駆動シリンダへの作動流体通路にアキュムレータを設け、圧力検出器により該アキュムレータあるいは前記作動流体通路の作動流体圧力を検出し、制御装置において該作動流体圧力の検出値に基づき前記駆動シリンダの作動流体圧力が前記射出成形機の必要駆動圧力になるように駆動シリンダの電磁弁を開閉制御して、水圧作動中の駆動シリンダにおける作動流体圧力を射出成形機の必要駆動圧力に制御するので、射出成形機のホッパから射出シリンダ内にチップを充填していて水圧作動を必要としない不作動の射出成形機用駆動シリンダの電磁弁を閉として前記不作動の射出成形機用駆動シリンダへの作動流体の供給を遮断することにより、アキュムレータ内を含む作動流体通路の圧力を射出成形機の必要駆動圧力に常時保持しつつ、不作動の射出成形機用駆動シリンダの無駄な作動を回避し、複数の射出成形機のうち射出作動中の射出成形機つまり駆動シリンダによる流体作動を行っている射出成形機を所要の流体作動期間のみ作動させて間歇的に運転することが可能となる。
【００１５】
従って、かかる発明によれば、作動流体通路の圧力を射出成形機の必要駆動圧力に常時保持しつつ、不作動の射出成形機用駆動シリンダへの作動流体の供給を遮断し射出作動中の射出成形機の駆動シリンダにのみ作動流体を供給することにより、複数台の射出成形機のうち、射出作動中の射出成形機のみの間歇運転を行うことができ、水圧ポンプを含む油圧供給系に無駄な動力が付与されることがなくなり、射出成形機の駆動エネルギー損失が低減され、油圧供給系の駆動動力を低減できて射出成形システムの効率を向上することができる。
【００１６】
また、前記のように、不作動の射出成形機用駆動シリンダへの作動流体の供給を遮断して射出作動中の射出成形機のみの間歇運転を行うことが可能となるので、作動流体（水）の漏れ等の不具合が発生することが少なくなり、射出成形システムの信頼性及び整備性が向上する。
【００１７】
さらに請求項３のように構成すれば、作動流体圧力の検出値に基づき水圧ポンプ駆動用の可変速モータの回転数を制御することにより、該可変速モータの回転数制御と前記アキュムレータによる作動流体圧力の補償作用との共働により、前記射出作動中の射出成形機のみの間歇運転に伴う作動流体供給量の調整を高い応答性で以って高精度で行うことができる。
【００１８】
【発明の実施の形態】
以下、本発明を図に示した実施例を用いて詳細に説明する。但し、この実施例に記載されている構成部品の寸法、材質、形状、その相対配置などは特に特定的な記載がない限り、この発明の範囲をそれのみに限定する趣旨ではなく、単なる説明例にすぎない。
【００１９】
図１は本発明の実施例に係る射出成形機の水圧駆動装置の全体構成図、図２は制御ブロック図である。
【００２０】
本発明の実施例に係る射出成形機の水圧駆動装置の全体構成を示す図１において、２は可変速モータ、１は該可変速モータ２に直結駆動される水圧ポンプである。９は複数個の水圧シリンダで、各水圧シリンダ９の出力ロッド９２には射出成形機０１０（図３参照）が連結されている。９３は該水圧シリンダ９のシリンダ、９１は該シリンダ９３内に往復摺動自在に嵌合されたピストンで、前記シリンダ内は該ピストン９１により２つの水室９４、９５により区画されている。
前記水圧ポンプ１の吐出口は作動水主管（作動流体管）６に接続され、作動水主管は複数の作動水管１０に分岐されている。
【００２１】
８は前記各作動水管１０に設けられて前記水圧シリンダ９への作動流体の供給、遮断を制御する電磁弁である。該電磁弁８の入口ポートは前記作動水管１０に接続され出口ポートは前記水圧シリンダ９の２つの水室９４、９５に接続されている。
即ち、かかる実施例においては、可変速モータ２に駆動される単一の水圧ポンプ１から送出される作動水により、複数台の射出成形機に夫々設けられた水圧シリンダ９を駆動するように構成されている。
【００２２】
３は前記作動水主管６に設けられたアキュムレータで、前記作動水主管６に連通される水圧室３３と背圧管５に連通される背圧室３２とをダイヤフラム３１にて区画して構成される。３ａは前記水圧室３３と作動水主管６との間を連通あるいは遮断するアキュムレータ弁、４は前記背圧室３２と背圧管５との間を連通あるいは遮断する背圧弁である。
【００２３】
１１は前記アキュムレータ３の水圧室３３内（あるいは作動水主管６内でもよい）の作動水圧力を検出する圧力検出器、１３は前記水圧シリンダ９における出力ロッド９２の変位を検出する射出成形機作動検出器、７は後述する制御操作を行う制御装置であり、前記圧力検出器１１からの作動水圧力の検出信号及び射出成形機作動検出器１３からの出力ロッド９２の変位つまり射出成形機のスクリュー０１５（図３参照）の変位は前記制御装置７に入力される。
そして該制御装置７においては、前記作動水圧力の検出信号及び射出成形機への出力ロッド９２の変位の検出信号に基づき後述するような制御操作を行い、その出力信号を前記各電磁弁８及び可変速モータ２に出力する。
【００２４】
次に、図２に基づき、かかる構成からなる射出成形機の水圧駆動装置の動作について説明する。
前記圧力検出器１１からの作動水圧力の検出信号は制御装置７の圧力比較部７１に入力される。７２はシリンダ作動圧力設定部で、前記射出成形機の必要駆動圧力つまり該射出成形機を適正に作動させる為に要する水圧シリンダ９の圧力が設定されている。該シリンダ作動圧力設定部に設定されている必要駆動圧力の設定値は前記圧力比較部７１に入力される。
【００２５】
該圧力比較部７１においては、前記作動水圧力の検出値と水圧シリンダ９の必要駆動圧力の設定値とを比較しその比較結果つまり圧力偏差の算出値を遮断シリンダ選定部７３に入力する。
一方、該遮断シリンダ選定部７３には前記射出成形機作動検出器１３から水圧シリンダ９の出力ロッド９２変位つまり射出成形機の作動状況検知信号が入力されている。
該遮断シリンダ選定部７３においては、前記各水圧シリンダ９の出力ロッド９２の変位検出信号に基づき、各水圧シリンダ９の前記変位が当該射出成形機の作動位置にあるか不作動位置にあるか、すなわち該射出成形機が射出シリンダ内にチップを充填している状態にあるか否かを判定し、不作動位置にある水圧シリンダ９を選出する。
【００２６】
ここで、この実施例のように、単一の水圧ポンプ１から複数の水圧シリンダ９に作動水を供給するシステムにおいては、作動している複数の水圧シリンダ９のうち、水圧ポンプ１の吐出流量を変化させない状態で、電磁弁８を閉じて１個または複数個の水圧シリンダ９への作動水の供給を遮断すると、アキュムレータ３の水圧室３３内及び作動水主管６内の圧力、即ち作動している水圧シリンダ９側の作動水圧力が上昇する。
そこで、前記遮断シリンダ選定部７３においては、前記圧力偏差の算出値に基づき該圧力偏差をゼロ（０）にして前記各水圧シリンダ９の作動水圧力を前記必要駆動圧力に上昇させる為に要する電磁弁８の遮断数つまり前記水圧シリンダ９への作動水供給の遮断数を算出する。
【００２７】
そして、該遮断シリンダ選定部７３においては、前記判定により選出された不作動位置にある水圧シリンダ９のうちから、前記のようにして算出された遮断数の水圧シリンダ９を選出し、当該水圧シリンダ９の電磁弁８を閉じて作動水の供給を遮断する。
これにより、前記アキュムレータ３の水圧室３３内及び作動水主管６内の作動水圧力が前記必要駆動圧力まで上昇して、前記アキュムレータ３の補償作用により作動している水圧シリンダ９側の作動水圧力が前記必要駆動圧力に保持される。
従って、かかる不作動射出成形機用水圧シリンダ９への作動水の供給遮断により、水圧ポンプ１を一定の吐出流量で作動させた状態で、作動射出成形機用水圧シリンダ９側の作動水圧力を前記必要駆動圧力まで上昇させ、該必要駆動圧力に保持することが可能となる。
【００２８】
７４はモータ制御部で、前記圧力比較部７１からの圧力偏差の算出値及び前記遮断シリンダ選定部７３における作動水遮断水圧シリンダ９の選定結果が入力される。
そして、該モータ制御部７４においては、遮断シリンダ選定部７３にて選定された水圧シリンダ９の作動水遮断により、前記アキュムレータ３の水圧室３３内及び作動水主管６内の作動水圧力即ち作動中の水圧シリンダ９側の作動水圧力が前記必要駆動圧力を超えたときには前記可変速モータ２の回転数を減少させる。
これにより、前記水圧ポンプ１の吐出量が減少し、前記作動水圧力は前記必要駆動圧力まで低下せしめられ、該必要駆動圧力に保持される。
【００２９】
また、前記モータ制御部においては、遮断シリンダ選定部７３にて選定された水圧シリンダ９の作動水遮断により、前記アキュムレータ３の水圧室３３内及び作動水主管６内の作動水圧力即ち作動中の水圧シリンダ９側の作動水圧力が前記必要駆動圧力を下回るときには前記可変速モータ２の回転数を増大させる。
これにより、前記水圧ポンプ１の吐出量が増大し、前記作動水圧力は前記必要駆動圧力まで上昇せしめられ、該必要駆動圧力に保持される。
【００３０】
このように、前記圧力比較部７１からの圧力偏差に基づき水圧ポンプ１駆動用の可変速モータ２の回転数を制御することにより、該可変速モータ２の回転数制御と前記アキュムレータ３による作動水圧力の補償作用との共働により、前記射出作動中の射出成形機のみの間歇運転に伴う作動水供給量の調整を高い応答性で以って高精度で行うことができる。
【００３１】
【発明の効果】
以上記載の如く本発明によれば、射出成形機システムの作動流体として無公害で投棄性の良好な水を用いた水圧駆動システムを備えたので、従来の油圧による駆動システムのように、オイルミストの飛散や油漏れが生じた際における機器周辺の汚染等の問題がなく、環境衛生面において好適なシステムが得られる。
また、水圧漏れが生じた場合にも、水は投棄性が良好であり周辺の汚染がないので修理や整備が簡単にでき、従来の油圧駆動システムに比べて整備性が向上する。
【００３２】
また、作動流体通路の圧力を射出成形機の必要駆動圧力に常時保持しつつ、不作動の射出成形機用駆動シリンダへの作動流体の供給を遮断し射出作動中の射出成形機の駆動シリンダにのみ作動流体を供給することにより、複数台の射出成形機のうち、射出作動中の射出成形機のみの間歇運転を行うことができ、水圧ポンプを含む油圧供給系に無駄な動力が付与されることがなくなり、射出成形機の駆動エネルギー損失が低減され、油圧供給系の駆動動力を低減できて射出成形システムの効率を向上することができる。
【００３３】
また、前記のように、不作動の射出成形機用駆動シリンダへの作動流体の供給を遮断して射出作動中の射出成形機のみの間歇運転を行うことが可能となるので、作動流体（水）の漏れ等の不具合が発生することが少なくなり、射出成形システムの信頼性及び整備性が向上する。
【００３４】
さらに請求項３のように構成すれば、作動流体圧力の検出値に基づき水圧ポンプ駆動用の可変速モータの回転数を制御することにより、該可変速モータの回転数制御と前記アキュムレータによる作動流体圧力の補償作用との共働により、前記射出作動中の射出成形機のみの間歇運転に伴う作動流体供給量の調整を高い応答性で以って高精度で行うことができる。
【図面の簡単な説明】
【図１】本発明の実施例に係る射出成形機の水圧駆動装置の全体構成図、図２は制御ブロック図である。
【図２】前記実施例における制御ブロック図である。
【図３】射出成形機及びその駆動装置の構成図である。
【符号の説明】
０１０ 射出成形機
１ 水圧ポンプ
２ 可変速モータ
３ アキュムレータ
６ 作動水主管
７ 制御装置
８ 電磁弁
９ 水圧シリンダ
１０ 作動水管
１１ 圧力検出器
１３ 射出成形機作動検出器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a hydraulic drive for an injection molding machine, comprising a plurality of injection molding machines, and a drive cylinder for each of the injection molding machines and an electromagnetic valve for controlling supply and cutoff of a working fluid to the drive cylinder. Equipment related.
[0002]
[Prior art]
FIG. 3 shows a conventional example of an injection molding machine and a driving device thereof disclosed in, for example, JP-A-2001-150120.
In the drawing, reference numeral 010 denotes an injection molding machine; 018, a drive cylinder for reciprocatingly driving the injection molding machine 010; a screw 015 is driven to rotate by a metering motor; Send it out to 016.
The chip 013 measured according to the rotation speed of the screw 015 is heated by a heater 017 installed on the outer periphery of the cylinder 011 when moving in the cylinder 011 to become a molten chip (melt).
[0003]
On the other hand, the pressurized hydraulic oil from the hydraulic pressure source 022 is sent to and stored in the accumulator 021 through the check valve. Reference numeral 024 denotes a direction switching flow control valve, and 025 denotes an ACC switching valve. The flow direction to the pipes 027 and 028 is set as indicated by the left arrow of the direction switching flow control valve 024. When set and opened as described above, the hydraulic oil stored in the accumulator 021 is sent to the oil chamber 018a of the drive cylinder 018 via the pipes 027 and 028.
[0004]
Accordingly, the injection piston 018 is pressed in the direction of the nozzle 016, and the hydraulic oil in the oil chamber 018b on the opposite side is discharged to the container via the pipe 028. Hydraulic oil is stored in the accumulator 021 by the source 022.
When the piston 018 is pressed by the hydraulic oil in the oil chamber 018a, the molten tip 013 at the tip of the cylinder 011 is injected into the mold. Reference numeral 029 denotes a hydraulic pressure source switching valve.
[0005]
[Problems to be solved by the invention]
The hydraulically driven injection molding machine as shown in FIG. 3 is equipped with one injection molding machine 010 and one set of hydraulic supply systems including a hydraulic source 022 for each drive cylinder 018.
Therefore, when installing a plurality of injection molding machines 010 and drive cylinders 018, it is necessary to equip a plurality of sets of hydraulic pressure supply systems corresponding to the injection molding machines 010 and drive cylinders 018. And the equipment cost increases.
Also, in such a hydraulic drive injection molding machine, the hydraulic system including the hydraulic pressure source 022 requires the hydraulic pressure of the drive cylinder 018 while the cylinder 011 is being filled with the chip 013 from the hopper 012 of the injection molding machine. The operation rate of the injection molding machine system must be reduced because it is necessary to always operate while maintaining the hydraulic pressure.
[0006]
As one of means for dealing with such a problem, the invention of Japanese Patent Application Laid-Open No. H8-332659 has been proposed.
In this invention, an electromagnetic switching valve is provided for each of a plurality of injection molding machines and driving cylinders, and a hydraulic oil path from a set of hydraulic systems including a hydraulic pump driven by a motor is connected to each of the electromagnetic switching valves. An accumulator for reducing hydraulic pulsation is provided in the working oil passage.
In the invention, a pressure sensor for detecting the pressure in the accumulator is provided, and when the detected pressure value is equal to or lower than a lower limit pressure set in the pressure sensor itself, the hydraulic oil of the hydraulic power source is operated by the hydraulic power source side solenoid valve. To the accumulator to increase the pressure in the hydraulic oil passage, and when the detected pressure value exceeds the upper limit pressure set in the pressure sensor itself, the hydraulic oil from the hydraulic source is sent to the accumulator by the hydraulic source side solenoid valve to perform the operation. It is configured to increase the pressure of the oil passage.
[0007]
However, in this invention, since the working fluid is oil (oil pressure) (the same applies to the drive cylinder of the injection molding machine in FIG. 3), maintenance when oil leakage occurs is complicated, maintenance is not good, and The surrounding area is easily stained with oil mist, and there are environmental issues.
Further, in this invention, the pressure of the accumulator and the working oil passage is detected, and the operation of the hydraulic power source side is controlled by the detection signal so that the pressure of the accumulator and the working oil passage is always set to the allowable upper limit pressure and the lower limit pressure. In this case, there is no means for individually controlling opening and closing of the electromagnetic switching valve at an appropriate timing for each of the plurality of injection molding machines and drive cylinders. Is always operated with the working pressure adjusted by the pressure sensor, the accumulator and the hydraulic pressure source side solenoid valve.
[0008]
For this reason, in such a conventional technology, a part of the plurality of injection molding machines fills the tip of the hopper into the cylinder, and despite the fact that there is a machine that does not substantially require the driving power, the hydraulic pressure is reduced. Since hydraulic oil is constantly supplied from the supply system to all of the plurality of injection molding machines at the required operating pressure, wasteful power is applied to the hydraulic supply system, and energy loss increases. Low efficiency.
Further, as described above, since the operating oil at the operating pressure is constantly supplied to the driving cylinder of the injection molding machine while the chips are being filled in the cylinder, malfunctions of the operating oil system such as leakage of the operating oil occur. It is easy, and there are also problems in the reliability and maintainability of the system.
[0009]
The present invention has been made in view of the problems of the related art, and in an injection molding machine system including a plurality of injection molding machines and drive cylinders, the drive energy loss is reduced, the operation efficiency of the system is improved, and good system surroundings are improved. It is an object of the present invention to provide a hydraulic drive device for an injection molding machine that maintains an environment, has less occurrence of failures, and has improved reliability and maintainability.
[0010]
[Means for Solving the Problems]
In order to solve this problem, the present invention is configured such that an injection screw is reciprocated by a drive cylinder including a cylinder and a piston reciprocally fitted in the cylinder. A plurality of injection molding machines, each of which is provided with the drive cylinder and a solenoid valve for controlling the supply and shutoff of a working fluid to the drive cylinder. Hydraulic pressure supply means for forming a cylinder into a hydraulic cylinder using water as the working fluid, and supplying working fluid to each of the solenoid valves and each hydraulic cylinder from a single hydraulic pump driven by a variable speed motor through a working fluid passage. A hydraulic drive device for an injection molding machine characterized by comprising:
[0011]
According to a second aspect of the present invention, in addition to the first aspect, an accumulator provided in the working fluid passage, and pressure detection for detecting a working fluid pressure in the accumulator or the working fluid passage communicated with the working fluid passage. And a detection signal of the working fluid pressure from the pressure detector is input, and a working fluid pressure in a hydraulic cylinder of the drive cylinder during hydraulic operation of the injection molding machine is based on a detection value of the working fluid pressure. A control device for selectively controlling the opening and closing of the solenoid valve so as to attain a necessary driving pressure.
[0012]
In addition, preferably, in addition to the second aspect, the third aspect further includes a control unit that controls a rotation speed of the variable speed motor based on a detected value of the working fluid pressure.
[0013]
According to this invention, the injection molding machine system is provided with the hydraulic drive system using non-polluting and well-disposable water as the working fluid of the system. There is no problem such as contamination around the equipment when the oil is scattered or oil leaks, and a system suitable for environmental hygiene can be obtained.
Further, even in the case of a hydraulic pressure leak, since water is well dumped and there is no contamination in the surrounding area, repair and maintenance can be easily performed, and maintainability is improved as compared with a conventional hydraulic drive system.
[0014]
Further, an accumulator is provided in a working fluid passage to a drive cylinder of the injection molding machine, a working fluid pressure of the accumulator or the working fluid passage is detected by a pressure detector, and the control device performs the above based on a detected value of the working fluid pressure. Control the opening and closing of the solenoid valve of the drive cylinder so that the working fluid pressure of the drive cylinder becomes the required drive pressure of the injection molding machine, and control the hydraulic fluid pressure in the drive cylinder during hydraulic operation to the required drive pressure of the injection molding machine. The injection cylinder is filled with chips from the hopper of the injection molding machine and does not require hydraulic operation. By shutting off the supply of the working fluid to the injection molding machine, the pressure of the working fluid passage including the inside of the accumulator always becomes the required driving pressure of the injection molding machine. It is necessary to avoid the useless operation of the inoperative drive cylinder for the injection molding machine while holding it, and to use the injection molding machine during the injection operation, that is, the injection molding machine performing the fluid operation by the drive cylinder among the plurality of injection molding machines. It is possible to operate only during the fluid operation period and operate intermittently.
[0015]
Therefore, according to the invention, the supply of the working fluid to the inactive drive cylinder for the injection molding machine is interrupted while the pressure of the working fluid passage is always maintained at the required driving pressure of the injection molding machine, and the injection during the injection operation is performed. By supplying the working fluid only to the drive cylinder of the molding machine, the intermittent operation of only the injection molding machine during the injection operation among the plurality of injection molding machines can be performed, and the hydraulic supply system including the hydraulic pump is wasted. Power is not applied, the driving energy loss of the injection molding machine is reduced, the driving power of the hydraulic supply system can be reduced, and the efficiency of the injection molding system can be improved.
[0016]
Further, as described above, the supply of the working fluid to the inactive injection molding machine drive cylinder can be interrupted and the intermittent operation of only the injection molding machine during the injection operation can be performed. The occurrence of problems such as leakage in ()) is reduced, and the reliability and maintainability of the injection molding system are improved.
[0017]
Further, according to the present invention, the rotation speed of the variable speed motor for driving the hydraulic pump is controlled based on the detected value of the working fluid pressure, thereby controlling the rotation speed of the variable speed motor and the working fluid by the accumulator. By cooperating with the pressure compensating action, the adjustment of the working fluid supply amount accompanying the intermittent operation of only the injection molding machine during the injection operation can be performed with high responsiveness and high accuracy.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail using embodiments shown in the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. It's just
[0019]
FIG. 1 is an overall configuration diagram of a hydraulic drive device of an injection molding machine according to an embodiment of the present invention, and FIG. 2 is a control block diagram.
[0020]
In FIG. 1, which shows the overall configuration of a hydraulic driving device for an injection molding machine according to an embodiment of the present invention, reference numeral 2 denotes a variable speed motor, and 1 denotes a hydraulic pump directly driven by the variable speed motor 2. Reference numeral 9 denotes a plurality of hydraulic cylinders, and an injection molding machine 010 (see FIG. 3) is connected to an output rod 92 of each hydraulic cylinder 9. 93 is a cylinder of the hydraulic cylinder 9, 91 is a piston fitted reciprocally slidably in the cylinder 93, and the inside of the cylinder is partitioned by the piston 91 into two water chambers 94 and 95.
The discharge port of the hydraulic pump 1 is connected to a working water main pipe (working fluid pipe) 6, and the working water main pipe is branched into a plurality of working water pipes 10.
[0021]
Reference numeral 8 denotes an electromagnetic valve provided in each of the working water pipes 10 to control supply and cutoff of a working fluid to the hydraulic cylinder 9. The inlet port of the solenoid valve 8 is connected to the working water pipe 10, and the outlet port is connected to two water chambers 94 and 95 of the hydraulic cylinder 9.
That is, in the embodiment, the hydraulic cylinders 9 provided in each of the plurality of injection molding machines are driven by the working water sent from the single hydraulic pump 1 driven by the variable speed motor 2. Have been.
[0022]
Reference numeral 3 denotes an accumulator provided in the working water main pipe 6. The accumulator 3 is configured by dividing a hydraulic chamber 33 communicating with the working water main pipe 6 and a back pressure chamber 32 communicating with the back pressure pipe 5 with a diaphragm 31. . An accumulator valve 3a communicates or shuts off between the hydraulic chamber 33 and the main working water pipe 6, and a back pressure valve 4 communicates or shuts off between the back pressure chamber 32 and the back pressure pipe 5.
[0023]
Reference numeral 11 denotes a pressure detector for detecting the working water pressure in the hydraulic chamber 33 of the accumulator 3 (or the working water main pipe 6), and reference numeral 13 denotes the operation of the injection molding machine for detecting the displacement of the output rod 92 in the hydraulic cylinder 9. A detector 7 is a control device for performing a control operation to be described later, and includes a detection signal of the operating water pressure from the pressure detector 11 and a displacement of the output rod 92 from the injection molding machine operation detector 13, that is, a screw of the injection molding machine. The displacement 015 (see FIG. 3) is input to the control device 7.
The control device 7 performs a control operation as described later based on the detection signal of the working water pressure and the detection signal of the displacement of the output rod 92 to the injection molding machine, and outputs the output signal to each of the electromagnetic valves 8 and Output to the variable speed motor 2.
[0024]
Next, the operation of the hydraulic drive device of the injection molding machine having the above configuration will be described with reference to FIG.
The detection signal of the working water pressure from the pressure detector 11 is input to the pressure comparison unit 71 of the control device 7. Reference numeral 72 denotes a cylinder operating pressure setting unit which sets a necessary driving pressure of the injection molding machine, that is, a pressure of the hydraulic cylinder 9 required for properly operating the injection molding machine. The set value of the required driving pressure set in the cylinder operating pressure setting unit is input to the pressure comparison unit 71.
[0025]
The pressure comparison unit 71 compares the detected value of the working water pressure with the set value of the required driving pressure of the hydraulic cylinder 9, and inputs the comparison result, that is, the calculated value of the pressure deviation, to the shutoff cylinder selection unit 73.
Meanwhile, the displacement of the output rod 92 of the hydraulic cylinder 9, that is, the operation state detection signal of the injection molding machine is input from the injection molding machine operation detector 13 to the shut-off cylinder selecting section 73.
In the shutoff cylinder selecting section 73, based on the displacement detection signal of the output rod 92 of each hydraulic cylinder 9, whether the displacement of each hydraulic cylinder 9 is in the working position or the non-working position of the injection molding machine, That is, it is determined whether or not the injection molding machine is in a state where the injection cylinder is being filled with chips, and the hydraulic cylinder 9 at the inoperative position is selected.
[0026]
Here, in a system for supplying working water from a single hydraulic pump 1 to a plurality of hydraulic cylinders 9 as in this embodiment, the discharge flow rate of the hydraulic pump 1 among a plurality of operating hydraulic cylinders 9 When the solenoid valve 8 is closed and the supply of hydraulic water to one or a plurality of hydraulic cylinders 9 is interrupted without changing the pressure, the pressure in the hydraulic chamber 33 of the accumulator 3 and the hydraulic water main pipe 6, that is, the operation is started. The working water pressure on the hydraulic cylinder 9 side increases.
Therefore, the shut-off cylinder selecting section 73 sets the pressure deviation to zero (0) based on the calculated value of the pressure deviation, and sets the pressure deviation to zero (0) to increase the working water pressure of each hydraulic cylinder 9 to the required driving pressure. The number of shutoffs of the valve 8, that is, the number of shutoffs of the supply of the working water to the hydraulic cylinder 9 is calculated.
[0027]
Then, the shutoff cylinder selecting section 73 selects the shutoff number of the hydraulic cylinders 9 calculated as described above from the hydraulic cylinders 9 at the inoperative position selected by the above-described determination. The solenoid valve 8 of 9 is closed to shut off the supply of the working water.
As a result, the hydraulic water pressure in the hydraulic chamber 33 of the accumulator 3 and the hydraulic water main pipe 6 rises to the required driving pressure, and the hydraulic water pressure on the hydraulic cylinder 9 side operated by the compensating action of the accumulator 3. Is maintained at the required driving pressure.
Therefore, by shutting off the supply of the working water to the hydraulic cylinder 9 for the non-working injection molding machine, the working water pressure on the working cylinder for the working injection molding machine 9 is reduced while the hydraulic pump 1 is operated at a constant discharge flow rate. It is possible to raise the pressure to the required driving pressure and to maintain the required driving pressure.
[0028]
Reference numeral 74 denotes a motor control unit to which the calculated value of the pressure deviation from the pressure comparison unit 71 and the selection result of the hydraulic water shutoff hydraulic cylinder 9 by the shutoff cylinder selection unit 73 are input.
In the motor control unit 74, the hydraulic water pressure in the hydraulic chamber 33 of the accumulator 3 and the hydraulic water main pipe 6, that is, during operation, is cut off by the hydraulic water of the hydraulic cylinder 9 selected by the shutoff cylinder selecting unit 73. When the operating water pressure on the hydraulic cylinder 9 side exceeds the required driving pressure, the rotation speed of the variable speed motor 2 is reduced.
As a result, the discharge amount of the hydraulic pump 1 is reduced, and the operating water pressure is reduced to the required driving pressure, and is maintained at the required driving pressure.
[0029]
In the motor control unit, the hydraulic water pressure in the hydraulic chamber 33 of the accumulator 3 and the hydraulic water main pipe 6, that is, the operating water pressure in the hydraulic water chamber 33 of the accumulator 3 is controlled by shutting off the hydraulic water of the hydraulic cylinder 9 selected by the shutoff cylinder selecting unit 73. When the operating water pressure on the hydraulic cylinder 9 side falls below the required driving pressure, the rotation speed of the variable speed motor 2 is increased.
As a result, the discharge amount of the hydraulic pump 1 increases, and the working water pressure is increased to the required driving pressure, and is maintained at the required driving pressure.
[0030]
As described above, by controlling the rotation speed of the variable speed motor 2 for driving the hydraulic pump 1 based on the pressure deviation from the pressure comparison unit 71, the rotation speed control of the variable speed motor 2 and the operation water by the accumulator 3 are controlled. By cooperating with the pressure compensating action, it is possible to adjust the supply amount of the working water with the intermittent operation of only the injection molding machine during the injection operation with high responsiveness and high accuracy.
[0031]
【The invention's effect】
As described above, according to the present invention, since a hydraulic drive system using non-polluting and well-disposable water as a working fluid of an injection molding machine system is provided, an oil mist is provided as in a conventional hydraulic drive system. There is no problem such as contamination around the equipment when the oil is scattered or oil leaks, and a system suitable for environmental hygiene can be obtained.
Further, even in the case of a hydraulic pressure leak, since water is well dumped and there is no contamination in the surrounding area, repair and maintenance can be easily performed, and maintainability is improved as compared with a conventional hydraulic drive system.
[0032]
In addition, while always maintaining the pressure of the working fluid passage at the required driving pressure of the injection molding machine, the supply of the working fluid to the inoperative drive cylinder of the injection molding machine is cut off, and the drive cylinder of the injection molding machine during the injection operation is cut off. By supplying only the working fluid, only the injection molding machine during the injection operation among the plurality of injection molding machines can be operated intermittently, and wasteful power is applied to the hydraulic supply system including the hydraulic pump. As a result, the driving energy loss of the injection molding machine is reduced, the driving power of the hydraulic supply system can be reduced, and the efficiency of the injection molding system can be improved.
[0033]
Further, as described above, the supply of the working fluid to the inactive injection molding machine drive cylinder can be interrupted and the intermittent operation of only the injection molding machine during the injection operation can be performed. The occurrence of problems such as leakage in ()) is reduced, and the reliability and maintainability of the injection molding system are improved.
[0034]
Further, according to the present invention, the rotation speed of the variable speed motor for driving the hydraulic pump is controlled based on the detected value of the working fluid pressure, thereby controlling the rotation speed of the variable speed motor and the working fluid by the accumulator. By cooperating with the pressure compensating action, the adjustment of the working fluid supply amount accompanying the intermittent operation of only the injection molding machine during the injection operation can be performed with high responsiveness and high accuracy.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a hydraulic drive device of an injection molding machine according to an embodiment of the present invention, and FIG. 2 is a control block diagram.
FIG. 2 is a control block diagram in the embodiment.
FIG. 3 is a configuration diagram of an injection molding machine and a driving device thereof.
[Explanation of symbols]
010 Injection molding machine 1 Water pressure pump 2 Variable speed motor 3 Accumulator 6 Working water main pipe 7 Control device 8 Solenoid valve 9 Water pressure cylinder 10 Working water pipe 11 Pressure detector 13 Injection molding machine operation detector
