JP3781483B2

JP3781483B2 - Screw support method and apparatus for injection molding machine

Info

Publication number: JP3781483B2
Application number: JP21239896A
Authority: JP
Inventors: 伸之中村
Original assignee: Nissei Plastic Industrial Co Ltd
Current assignee: Nissei Plastic Industrial Co Ltd
Priority date: 1996-08-12
Filing date: 1996-08-12
Publication date: 2006-05-31
Anticipated expiration: 2016-08-12
Also published as: JPH1052840A

Description

【０００１】
【発明の属する技術分野】
本発明は単一の駆動部材により平行に配した複数軸のスクリュを支持する射出成形機のスクリュ支持方法及び装置に関する。
【０００２】
【従来の技術】
従来、スクリュに対する成形材料の食込性及び可塑化時における樹脂の混練性を高めることを目的とした二軸のスクリュを備える成形装置は、特開昭５０−１５０７６３号公報で知られている。
【０００３】
ところで、一般的な射出成形機のように、射出シリンダの射出ピストン（駆動部材）により一軸のスクリュを支持する場合には、射出ピストンとスクリュが一体に回転可能となるが、射出ピストンにより二軸のスクリュを支持する場合には、スクリュの回転時に射出ピストンを回転させることが不可能となるため、各スクリュは射出ピストンに対して回転可能に結合する必要がある。
【０００４】
このため、上記公報に開示される従来の成形装置では、射出ピストンと各スクリュ間にベアリングを配設し、このベアリングを介して射出ピストンと各スクリュを回転可能に結合していた。
【０００５】
【発明が解決しようとする課題】
しかし、上述した従来の成形装置におけるスクリュ支持構造は、次のような問題点があった。
【０００６】
即ち、押出成形機として用いる場合には、成形時のスクリュに付与されるスラスト荷重の大きさは、概ね３００〜３５０ｋｇ／ｃｍ²程度であるため、スクリュを支持するベアリングは当該スラスト荷重に十分耐えることができるが、射出成形機として用いる場合には、射出時（スクリュ前進時）のスラスト荷重が、通常、１５００〜２０００ｋｇ／ｃｍ²程度になるため、かなり大きな荷重がベアリングに付与されることになる。
【０００７】
このため、ベアリングを用いた従来のスクリュ支持構造では、ベアリングの変形や破損等を招く虞れがあり信頼性を確保できないとともに、成形できる成形品がスラスト荷重の大きさに制限されてしまう難点があった。
【０００８】
本発明はこのような従来の技術に存在する課題を解決したものであり、駆動部材によりスクリュを支持する際における信頼性を飛躍的に高めることができるとともに、スクリュに付与されるスラスト荷重の大きさに制限されることなく射出成形を行うことができる射出成形機のスクリュ支持方法及び装置の提供を目的とする。
【０００９】
【課題を解決するための手段及び実施の形態】
本発明に係る射出成形機のスクリュ支持方法は、単一の駆動部材２により平行に配した複数軸のスクリュ３ｘ，３ｙを支持するに際し、駆動部材２の先端の凹部２１に設けた複数のシリンダ部４ｘ，４ｙにより、各スクリュ３ｘ，３ｙの後端軸部５ｘ，５ｙを軸方向に変位自在に支持するとともに、スクリュ３ｘ，３ｙの回転駆動時に、後端軸部５ｘ，５ｙの外周面とシリンダ部４ｘ，４ｙの内周面間の隙間及び凹部２１と後端軸部５ｘ，５ｙの後端面間に圧油を供給して当該後端軸部５ｘ，５ｙを設定位置Ｐｓまで変位させることによりシリンダ部４ｘ，４ｙと後端軸部５ｘ，５ｙを非接触にし、かつスクリュ３ｘ，３ｙの前進駆動時に、圧油の供給を解除して後端軸部５ｘ，５ｙの後端面を凹部２１に当接させるようにしたことを特徴とする。
【００１０】
また、本発明に係る射出成形機のスクリュ支持装置１は、駆動部材２の先端の凹部２１に複数のシリンダ部４ｘ，４ｙを設け、シリンダ部４ｘ，４ｙにより各スクリュ３ｘ，３ｙの後端軸部５ｘ，５ｙを軸方向に変位自在に支持するとともに、スクリュ３ｘ，３ｙの回転駆動時に、後端軸部５ｘ，５ｙの外周面とシリンダ部４ｘ，４ｙの内周面間の隙間及び凹部２１と後端軸部５ｘ，５ｙの後端面間に圧油を供給して当該後端軸部５ｘ，５ｙを設定位置Ｐｓまで変位させることによりシリンダ部４ｘ，４ｙと後端軸部５ｘ，５ｙを非接触にし、かつスクリュ３ｘ，３ｙの前進駆動時に、圧油の供給を解除して後端軸部５ｘ，５ｙの後端面を凹部２１に当接させる油圧回路部６を備えることを特徴とする。
【００１１】
この場合、好適な実施の形態により、油圧回路部６は後端軸部５ｘ，５ｙの軸方向における位置を検出する位置センサ７を有するとともに、シリンダ部４ｘ，４ｙと後端軸部５ｘ，５ｙ間に圧油を供給した際に、後端軸部５ｘ，５ｙが設定位置Ｐｓとなるように圧油の供給を制御する制御部８を備える。また、隙間Ｓｓｘ，Ｓｓｙには、一又は二以上の螺旋状の油通路Ｓｒ…が含まれる。
【００１２】
これにより、スクリュ３ｘ，３ｙの回転駆動時には、後端軸部５ｘ，５ｙの外周面とシリンダ部４ｘ，４ｙの内周面間の隙間及び凹部２１と後端軸部５ｘ，５ｙの後端面間に圧油が供給されるため、シリンダ部４ｘ，４ｙと後端軸部５ｘ，５ｙは非接触になり、スクリュ３ｘ，３ｙは円滑に回転するとともに、スクリュ３ｘ，３ｙの前進駆動時には、圧油の供給が解除されるため、後端軸部５ｘ，５ｙの後端面と凹部２１が接触し、スクリュ３ｘ，３ｙは駆動部材２と一体となって前進する。
【００１３】
【実施例】
次に、本発明に係る好適な実施例を挙げ、図面に基づき詳細に説明する。
【００１４】
まず、本実施例に係るスクリュ支持装置１を備える射出成形機Ｍの全体的構成について、図５及び図６を参照して説明する。
【００１５】
図５中、Ｎは射出成形機Ｍにおける型締装置を除く射出装置を示す。１１は加熱筒であり、前端に射出ノズル１２を有するとともに、後部にはホッパー（材料供給口）１３を有する。
【００１６】
また、加熱筒１１の内部には図６に示す左右一対のスクリュ挿通孔１４ｘ，１４ｙを有し、各スクリュ挿通孔１４ｘ，１４ｙにはスクリュ３ｘ，３ｙをそれぞれ挿入する。これにより、スクリュ３ｘと３ｙは平行に配した二軸のスクリュ機構を構成する。この場合、スクリュ３ｘ，３ｙに設けた螺旋条３ｘｓ，３ｙｓはそれぞれ反対方向となる。
【００１７】
一方、加熱筒１１の後端にはスクリュ駆動装置１５を備え、スクリュ駆動装置１５はスクリュ３ｘ，３ｙを進退駆動するスクリュ進退駆動部１６と、スクリュ３ｘ，３ｙを回転駆動するスクリュ回転駆動部１７を備える。スクリュ進退駆動部１６は射出シリンダ１８を有し、この射出シリンダ１８には片ロッドタイプの射出ピストン２ｐ（駆動部材２）を内蔵する。なお、射出ピストン２ｐは前方に突出したピストンロッド１９を有する。そして、射出ピストン２ｐ（ピストンロッド１９）の前端にはスクリュ支持装置１を設けて各スクリュ３ｘ，３ｙの後端を支持する。
【００１８】
次に、スクリュ支持装置１及びスクリュ回転駆動部１７の構成について、図１〜図４を参照して説明する。
【００１９】
まず、ピストンロッド１９の前端面には凹部２１を形成し、この凹部２１に軸受部材２０を嵌着する。この場合、凹部２１に挿入する軸受部材２０の端面と凹部２１の底面間には油室２２を設ける。一方、軸受部材２０には一対のシリンダ部４ｘ，４ｙを設ける。各シリンダ部４ｘ，４ｙの内端は油室２２を介して相連通する。また、各シリンダ部４ｘ，４ｙの内周面にはそれぞれ螺旋溝状の油通路Ｓｒ…を設ける。図２はシリンダ部４ｘの内周面を展開した油通路Ｓｒ…を示す。なお、実施例の油通路Ｓｒ…は３本であり、各油通路Ｓｒ…はそれぞれ独立し、両端は閉じている。さらに、軸受部材２０の内部には図３に示すように、油ジャケット２３を設け、この油ジャケット２３と各油通路Ｓｒ…の一端部を連通接続するとともに、油ジャケット２３は圧油の給油ポート２４に連通接続する。
【００２０】
他方、スクリュ３ｘ，３ｙの後端には後端軸部５ｘ，５ｙを設け、この後端軸部５ｘ，５ｙをシリンダ部４ｘ，４ｙに挿入する。この場合、後端軸部５ｘ，５ｙの径は、シリンダ部４ｘ，４ｙに挿入した際に、図４に示すように、当該後端軸部５ｘ，５ｙの外周面とシリンダ部４ｘ，４ｙの内周面間に、僅かなクリアランスＬｃが生ずる大きさを選定する。このクリアランスＬｃと油通路Ｓｒ…は、圧油が侵入可能な隙間Ｓｓｘ，Ｓｓｙを構成する。一方、ピストンロッド１９には油室２２に連通する排油ポート２５を設ける。また、凹部２１の底面には後端軸部５ｘの端面に対向する位置センサ７を配設する。この位置センサ７は、後端軸部５ｘの軸方向の位置を検出する。なお、実施例は後端軸部５ｘ側にのみ位置センサ７を設けたが、後端軸部５ｘと５ｙ側の双方に設けてもよい。
【００２１】
６は油圧回路部である。油圧回路部６は油圧ポンプ３１，リリーフ弁３２，方向切換弁３３，メータアウト回路を構成するリリーフ弁３４を備え、この油圧回路部６には前記給油ポート２４と排油ポート２５を接続する。また、油圧回路部６には制御部８を備える。制御部８の入力側には前記位置センサ７及び射出シリンダ１８の圧力を検出する圧力センサ３５を接続するとともに、出力側には方向切換弁３３及びドライバ３６を介してリリーフ弁３４を接続する。なお、３７は制御部８に接続した中央コントローラを示す。中央コントローラ３７ではシリンダ部４ｘ，４ｙと後端軸部５ｘ，５ｙ間に圧油を供給した際における後端軸部５ｘ，５ｙの変位量、即ち、設定位置Ｐｓを設定して制御部８に付与する。
【００２２】
一方、シリンダ部４ｘ，４ｙから露出した後端軸部５ｘ，５ｙの前部にはギア部４１ｘ，４１ｙをそれぞれ設け、各ギア部４１ｘと４１ｙは相噛合させる。また、一方のギア部４１ｙには伝達ギア部４２を噛合させ、この伝達ギア部４２に対して不図示の回転駆動部から回転が伝達されるように構成する。これにより、スクリュ回転駆動部１７が構成される。また、各ギア部４１ｘと４１ｙの前方に位置するスクリュ３ｘ，３ｙの後端は、軸受部材２０に一体に取付けた軸受プレート４３により回動自在に支持される。なお、Ｒ…はＯリングを示す。
【００２３】
次に、本実施例に係るスクリュ支持方法を含むスクリュ支持装置１の機能について、各図を参照して説明する。
【００２４】
まず、スクリュ３ｘ，３ｙの回転駆動時（計量時）には、スクリュ回転駆動部１７によりスクリュ３ｘ，３ｙが回転する。即ち、伝達ギア部４２の回転はギア部４１ｙ、さらに、ギア部４１ｘに伝達され、スクリュ３ｘ，３ｙはそれぞれ反対方向に同一速度で回転する。これにより、材料供給口１３から供給される成形材料は加熱筒１１内で可塑化混練されるとともに、溶融樹脂はスクリュ３ｘ，３ｙの前方に計量蓄積され、スクリュ３ｘ，３ｙは後退する。この場合、二軸のスクリュ機構により、一軸のスクリュに比べてスクリュ３ｘ，３ｙに対する成形材料の食込性及び可塑時における樹脂の混練性が高められる。
【００２５】
また、スクリュ３ｘ，３ｙの回転駆動時には、方向切換弁３３が切換えられ、油圧回路部６から給油ポート２４に圧油が供給されるとともに、さらに、圧油は油ジャケット２３を介して油通路Ｓｒ…を含む隙間Ｓｓｘ，Ｓｓｙに供給される。この結果、圧油はシリンダ部４ｘ，４ｙの内周面と後端軸部５ｘ，５ｙの外周面間に侵入し、後端軸部５ｘ，５ｙに対しラジアル方向に圧油が作用する。これにより、後端軸部５ｘ，５ｙは軸中心に位置し、シリンダ部４ｘ，４ｙの内周面と後端軸部５ｘ，５ｙの外周面は非接触となる。
【００２６】
さらに、隙間Ｓｓｘ，Ｓｓｙに供給された圧油は油室２２に供給され、後端軸部５ｘ，５ｙの端面に油圧が作用することにより、後端軸部５ｘ，５ｙを前方に変位させる。この際の変位量Ｌｓは位置センサ７により検出し、制御部８はリリーフ弁３４をフィードバック制御することにより、後端軸部５ｘ，５ｙを設定位置Ｐｓに維持する。なお、設定位置Ｐｓまでの変位量Ｌｓは、通常、０．１〜１．０ｍｍ程度に設定する。この結果、後端軸部５ｘ，５ｙの端面とシリンダ部４ｘ，４ｙの底面は非接触となる。
【００２７】
この場合、圧油は油通路Ｓｒ…を含む隙間Ｓｓｘ，Ｓｓｙを介して油室２２に供給されるため、後端軸部５ｘ，５ｙの外周面に作用する油圧は、隙間Ｓｓｘ，Ｓｓｙにより生ずる流体抵抗によって、後端軸部５ｘ，５ｙの端面に作用する油圧よりも高くなり、安定かつ的確な支持圧力が得られる。よって、スクリュ３ｘ，３ｙの回転時には、シリンダ部４ｘ，４ｙと後端軸部５ｘ，５ｙは非接触状態が維持され、スクリュ３ｘ，３ｙは円滑に回転する。
【００２８】
他方、スクリュ３ｘ，３ｙの前進駆動時（射出時）には、スクリュ進退駆動部１６における射出シリンダ１８により射出ピストン２ｐが前進し、スクリュ３ｘ，３ｙの前方に計量された溶融樹脂が射出ノズル１２から不図示の金型内に射出充填される。
【００２９】
また、スクリュ３ｘ，３ｙの前進駆動時には、方向切換弁３３を切換えることにより、給油ポート２４に対する圧油の供給を解除する。これにより、シリンダ部４ｘ，４ｙと後端軸部５ｘ，５ｙは接触し、スクリュ３ｘ，３ｙは駆動部材２と一体に前進する。
【００３０】
以上、実施例について詳細に説明したが、本発明はこのような実施例に限定されるものではない。例えば、実施例は二軸のスクリュを例示したが、三軸以上のスクリュであってもよい。また、駆動部材は射出ピストンを例示したが、サーボモータにより前進する駆動部材であってもよい。その他、細部の構成，形状，手法等において、本発明の要旨を逸脱しない範囲で任意に実施できる。
【００３１】
【発明の効果】
このように、本発明に係る射出成形機のスクリュ支持方法は、単一の駆動部材により平行に配した複数軸のスクリュを支持するに際し、駆動部材の先端の凹部に設けた複数のシリンダ部により、各スクリュの後端軸部を軸方向に変位自在に支持するとともに、スクリュの回転駆動時に、後端軸部の外周面とシリンダ部の内周面間の隙間及び凹部と後端軸部の後端面間に圧油を供給して後端軸部を設定位置まで変位させることによりシリンダ部と後端軸部を非接触にし、かつスクリュの前進駆動時に、圧油の供給を解除して後端軸部の後端面を凹部に当接させ、また、本発明に係る射出成形機のスクリュ支持装置は、駆動部材の先端の凹部に複数のシリンダ部を設け、シリンダ部により各スクリュの後端軸部を軸方向に変位自在に支持するとともに、スクリュの回転駆動時に、後端軸部の外周面とシリンダ部の内周面間の隙間及び凹部と後端軸部の後端面間に圧油を供給して後端軸部を設定位置まで変位させることによりシリンダ部と後端軸部を非接触にし、かつスクリュの前進駆動時に、圧油の供給を解除して後端軸部の後端面を凹部に当接させる油圧回路部を備えるため、駆動部材によりスクリュを支持する際における信頼性を飛躍的に高めることができるとともに、スクリュに付与されるスラスト荷重の大きさに制限されることなく射出成形を行うことができるという顕著な効果を奏する。
【図面の簡単な説明】
【図１】本発明に係るスクリュ支持装置の油圧回路部を含む断面側面図、
【図２】同スクリュ支持装置を構成するシリンダ部における内周面の展開図、
【図３】同スクリュ支持装置におけるシリンダ部と後端軸部の断面正面図、
【図４】本発明に係る射出成形機のスクリュ支持装置の要部を示す拡大断面側面図、
【図５】同スクリュ支持装置を備える射出成形機の全体的断面側面図、
【図６】同射出成形機の加熱筒における断面正面図、
【符号の説明】
１スクリュ支持装置
２駆動部材
３ｘ… スクリュ
４ｘ… シリンダ部
５ｘ… 後端軸部
６油圧回路部
７位置センサ
８制御部
２１凹部
Ｐｓ設定位置
Ｓｓｘ隙間
Ｓｒ… 油通路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screw support method and apparatus for an injection molding machine that supports a multi-axis screw arranged in parallel by a single drive member.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a molding apparatus provided with a biaxial screw for the purpose of improving the biting property of a molding material with respect to a screw and the kneading property of a resin during plasticization is known from Japanese Patent Laid-Open No. 50-150763.
[0003]
By the way, when a uniaxial screw is supported by an injection piston (drive member) of an injection cylinder as in a general injection molding machine, the injection piston and the screw can rotate integrally. When the screw is supported, it is impossible to rotate the injection piston when the screw is rotated. Therefore, each screw needs to be rotatably connected to the injection piston.
[0004]
For this reason, in the conventional molding apparatus disclosed in the above publication, a bearing is disposed between the injection piston and each screw, and the injection piston and each screw are rotatably coupled via this bearing.
[0005]
[Problems to be solved by the invention]
However, the screw support structure in the conventional molding apparatus described above has the following problems.
[0006]
That is, when used as an extrusion molding machine, the magnitude of the thrust load applied to the screw at the time of molding is about 300 to 350 kg / cm ² , so the bearing that supports the screw sufficiently withstands the thrust load. However, when used as an injection molding machine, the thrust load at the time of injection (screw advancement) is usually about 1500 to 2000 kg / cm ² , so that a considerably large load is applied to the bearing. Become.
[0007]
For this reason, in a conventional screw support structure using a bearing, there is a risk that deformation or damage of the bearing may occur, and reliability cannot be ensured, and the molded product that can be molded is limited to the size of the thrust load. there were.
[0008]
The present invention solves such a problem existing in the prior art, and can dramatically improve the reliability when the screw is supported by the driving member, and the thrust load applied to the screw is large. It is an object of the present invention to provide a screw support method and apparatus for an injection molding machine that can perform injection molding without being limited thereto.
[0009]
[Means for Solving the Problems and Embodiments]
The screw support method of the injection molding machine according to the present invention is such that a plurality of cylinders provided in the recesses 21 at the tip of the drive member 2 when supporting a plurality of screws 3x, 3y arranged in parallel by a single drive member 2. The rear end shaft portions 5x and 5y of the screws 3x and 3y are supported by the portions 4x and 4y so as to be displaceable in the axial direction, and when the screws 3x and 3y are driven to rotate, the outer peripheral surfaces of the rear end shaft portions 5x and 5y Pressure oil is supplied between the gap between the inner peripheral surfaces of the cylinder portions 4x and 4y and the recess 21 and the rear end surfaces of the rear end shaft portions 5x and 5y to displace the rear end shaft portions 5x and 5y to the set position Ps. Thus, the cylinder parts 4x, 4y and the rear end shaft parts 5x, 5y are brought into non-contact, and when the screws 3x, 3y are driven forward, the supply of pressure oil is released, and the rear end surfaces of the rear end shaft parts 5x, 5y are recessed. It is characterized by being made to contact That.
[0010]
Further, the screw support device 1 of the injection molding machine according to the present invention is provided with a plurality of cylinder portions 4x and 4y in the concave portion 21 at the tip of the driving member 2, and the rear end shafts of the screws 3x and 3y by the cylinder portions 4x and 4y. The portions 5x and 5y are supported so as to be displaceable in the axial direction, and the clearance between the outer peripheral surface of the rear end shaft portions 5x and 5y and the inner peripheral surface of the cylinder portions 4x and 4y and the concave portion 21 when the screws 3x and 3y are rotationally driven. Then, pressure oil is supplied between the rear end surfaces of the rear end shaft portions 5x and 5y to displace the rear end shaft portions 5x and 5y to the set position Ps, thereby connecting the cylinder portions 4x and 4y and the rear end shaft portions 5x and 5y. The hydraulic circuit unit 6 is provided so as to be non-contact and to release the supply of pressure oil and abut the rear end surfaces of the rear end shaft portions 5x and 5y against the recess 21 when the screws 3x and 3y are driven forward. .
[0011]
In this case, according to a preferred embodiment, the hydraulic circuit section 6 includes a position sensor 7 that detects the position of the rear end shaft sections 5x and 5y in the axial direction, and the cylinder sections 4x and 4y and the rear end shaft sections 5x and 5y. A control unit 8 is provided for controlling the supply of pressure oil so that the rear end shaft portions 5x and 5y are at the set position Ps when the pressure oil is supplied therebetween. Further, the gaps Ssx and Ssy include one or more spiral oil passages Sr.
[0012]
As a result, during the rotational driving of the screws 3x and 3y, the gap between the outer peripheral surface of the rear end shaft portions 5x and 5y and the inner peripheral surface of the cylinder portions 4x and 4y and the gap between the concave portion 21 and the rear end surfaces of the rear end shaft portions 5x and 5y. Since the pressure oil is supplied to the cylinder portions 4x and 4y and the rear end shaft portions 5x and 5y are not in contact with each other, the screws 3x and 3y rotate smoothly, and when the screws 3x and 3y are driven forward, the pressure oil Is released, the rear end surfaces of the rear end shaft portions 5x and 5y come into contact with the concave portion 21, and the screws 3x and 3y move forward together with the drive member 2.
[0013]
【Example】
Next, preferred embodiments according to the present invention will be given and described in detail with reference to the drawings.
[0014]
First, an overall configuration of an injection molding machine M including the screw support device 1 according to the present embodiment will be described with reference to FIGS. 5 and 6.
[0015]
In FIG. 5, N indicates an injection device excluding the mold clamping device in the injection molding machine M. A heating cylinder 11 has an injection nozzle 12 at the front end and a hopper (material supply port) 13 at the rear.
[0016]
The heating cylinder 11 has a pair of left and right screw insertion holes 14x and 14y shown in FIG. 6, and the screws 3x and 3y are inserted into the screw insertion holes 14x and 14y, respectively. Thereby, the screws 3x and 3y constitute a biaxial screw mechanism arranged in parallel. In this case, the spiral strips 3xs and 3ys provided on the screws 3x and 3y are in opposite directions.
[0017]
On the other hand, a screw driving device 15 is provided at the rear end of the heating cylinder 11, and the screw driving device 15 drives the screw 3x, 3y back and forth, and a screw rotation driving unit 17 drives the screws 3x, 3y to rotate. Is provided. The screw advancing / retreating drive unit 16 has an injection cylinder 18, and the injection cylinder 18 incorporates a single rod type injection piston 2p (drive member 2). The injection piston 2p has a piston rod 19 protruding forward. A screw support device 1 is provided at the front end of the injection piston 2p (piston rod 19) to support the rear ends of the screws 3x and 3y.
[0018]
Next, the structure of the screw support apparatus 1 and the screw rotation drive part 17 is demonstrated with reference to FIGS.
[0019]
First, a recess 21 is formed in the front end surface of the piston rod 19, and the bearing member 20 is fitted into the recess 21. In this case, an oil chamber 22 is provided between the end surface of the bearing member 20 to be inserted into the recess 21 and the bottom surface of the recess 21. On the other hand, the bearing member 20 is provided with a pair of cylinder portions 4x and 4y. The inner ends of the cylinder portions 4x and 4y communicate with each other via the oil chamber 22. Further, spiral groove-like oil passages Sr are provided on the inner peripheral surfaces of the cylinder portions 4x and 4y, respectively. FIG. 2 shows oil passages Sr... In which the inner peripheral surface of the cylinder portion 4x is developed. In the embodiment, there are three oil passages Sr, each oil passage Sr is independent and both ends are closed. Further, as shown in FIG. 3, an oil jacket 23 is provided inside the bearing member 20, and the oil jacket 23 and one end of each oil passage Sr are connected to each other, and the oil jacket 23 is an oil supply port for pressure oil. 24 is connected in communication.
[0020]
On the other hand, rear end shaft portions 5x and 5y are provided at the rear ends of the screws 3x and 3y, and the rear end shaft portions 5x and 5y are inserted into the cylinder portions 4x and 4y. In this case, when the rear end shaft portions 5x and 5y are inserted into the cylinder portions 4x and 4y, the outer end surfaces of the rear end shaft portions 5x and 5y and the cylinder portions 4x and 4y, as shown in FIG. A size at which a slight clearance Lc is generated between the inner peripheral surfaces is selected. This clearance Lc and the oil passages Sr ... constitute gaps Ssx, Ssy through which pressure oil can enter. On the other hand, the piston rod 19 is provided with an oil discharge port 25 communicating with the oil chamber 22. Further, a position sensor 7 facing the end surface of the rear end shaft portion 5x is disposed on the bottom surface of the recess 21. The position sensor 7 detects the position of the rear end shaft portion 5x in the axial direction. Although the position sensor 7 is provided only on the rear end shaft portion 5x side in the embodiment, it may be provided on both the rear end shaft portion 5x and the 5y side.
[0021]
6 is a hydraulic circuit part. The hydraulic circuit section 6 includes a hydraulic pump 31, a relief valve 32, a direction switching valve 33, and a relief valve 34 constituting a meter-out circuit, and the oil supply port 24 and the oil discharge port 25 are connected to the hydraulic circuit section 6. The hydraulic circuit unit 6 includes a control unit 8. A pressure sensor 35 for detecting the pressure of the position sensor 7 and the injection cylinder 18 is connected to the input side of the control unit 8, and a relief valve 34 is connected to the output side via a direction switching valve 33 and a driver 36. Reference numeral 37 denotes a central controller connected to the control unit 8. In the central controller 37, the displacement amount of the rear end shaft portions 5x, 5y when the pressure oil is supplied between the cylinder portions 4x, 4y and the rear end shaft portions 5x, 5y, that is, the set position Ps is set to the control unit 8. Give.
[0022]
On the other hand, gear portions 41x and 41y are respectively provided in front portions of the rear end shaft portions 5x and 5y exposed from the cylinder portions 4x and 4y, and the gear portions 41x and 41y are in mesh with each other. Further, the transmission gear portion 42 is engaged with the one gear portion 41y, and the rotation is transmitted to the transmission gear portion 42 from a rotation driving unit (not shown). Thereby, the screw rotation drive part 17 is comprised. The rear ends of the screws 3x and 3y located in front of the gear portions 41x and 41y are rotatably supported by a bearing plate 43 that is integrally attached to the bearing member 20. R ... represents an O-ring.
[0023]
Next, functions of the screw support device 1 including the screw support method according to the present embodiment will be described with reference to the drawings.
[0024]
First, when the screws 3x and 3y are rotationally driven (measured), the screws 3x and 3y are rotated by the screw rotational drive unit 17. That is, the rotation of the transmission gear portion 42 is transmitted to the gear portion 41y and further to the gear portion 41x, and the screws 3x and 3y rotate at the same speed in opposite directions. Thereby, the molding material supplied from the material supply port 13 is plasticized and kneaded in the heating cylinder 11, and the molten resin is measured and accumulated in front of the screws 3x and 3y, and the screws 3x and 3y move backward. In this case, the biaxial screw mechanism enhances the biting property of the molding material for the screws 3x and 3y and the kneading property of the resin at the time of plasticization as compared with the uniaxial screw.
[0025]
When the screws 3x and 3y are driven to rotate, the direction switching valve 33 is switched, pressure oil is supplied from the hydraulic circuit section 6 to the oil supply port 24, and the pressure oil is further passed through the oil jacket 23 to the oil passage Sr. Are supplied to the gaps Ssx and Ssy including. As a result, the pressure oil enters between the inner peripheral surfaces of the cylinder portions 4x and 4y and the outer peripheral surfaces of the rear end shaft portions 5x and 5y, and the pressure oil acts in the radial direction on the rear end shaft portions 5x and 5y. As a result, the rear end shaft portions 5x and 5y are located at the axial center, and the inner peripheral surfaces of the cylinder portions 4x and 4y and the outer peripheral surfaces of the rear end shaft portions 5x and 5y are not in contact with each other.
[0026]
Further, the pressure oil supplied to the gaps Ssx and Ssy is supplied to the oil chamber 22, and hydraulic pressure acts on the end surfaces of the rear end shaft portions 5x and 5y, thereby displacing the rear end shaft portions 5x and 5y forward. The displacement amount Ls at this time is detected by the position sensor 7, and the control unit 8 performs feedback control of the relief valve 34, thereby maintaining the rear end shaft portions 5x and 5y at the set position Ps. The displacement amount Ls up to the set position Ps is normally set to about 0.1 to 1.0 mm. As a result, the end surfaces of the rear end shaft portions 5x and 5y and the bottom surfaces of the cylinder portions 4x and 4y are not in contact with each other.
[0027]
In this case, since the pressure oil is supplied to the oil chamber 22 via the gaps Ssx and Ssy including the oil passages Sr..., The hydraulic pressure acting on the outer peripheral surfaces of the rear end shaft portions 5x and 5y is generated by the gaps Ssx and Ssy. The fluid resistance is higher than the hydraulic pressure acting on the end surfaces of the rear end shaft portions 5x and 5y, and a stable and accurate support pressure can be obtained. Therefore, when the screws 3x and 3y are rotated, the cylinder portions 4x and 4y and the rear end shaft portions 5x and 5y are maintained in a non-contact state, and the screws 3x and 3y rotate smoothly.
[0028]
On the other hand, when the screws 3x and 3y are driven forward (injection), the injection piston 2p is advanced by the injection cylinder 18 in the screw advance / retreat drive unit 16, and the molten resin measured in front of the screws 3x and 3y is injected into the injection nozzle 12. Are injected into a mold (not shown).
[0029]
Further, when the screws 3x and 3y are driven forward, the supply of pressure oil to the oil supply port 24 is canceled by switching the direction switching valve 33. Thereby, the cylinder portions 4x and 4y and the rear end shaft portions 5x and 5y come into contact with each other, and the screws 3x and 3y move forward together with the drive member 2.
[0030]
While the embodiments have been described in detail, the present invention is not limited to such embodiments. For example, although the example illustrated a biaxial screw, a triaxial or more screw may be used. Moreover, although the drive member illustrated the injection piston, the drive member advanced by a servomotor may be sufficient. In addition, the detailed configuration, shape, technique, and the like can be arbitrarily implemented without departing from the scope of the present invention.
[0031]
【The invention's effect】
As described above, the screw support method of the injection molding machine according to the present invention uses a plurality of cylinder portions provided in the recesses at the front end of the drive member when supporting a plurality of screws arranged in parallel by a single drive member. The rear end shaft portion of each screw is supported so as to be displaceable in the axial direction, and the clearance between the outer peripheral surface of the rear end shaft portion and the inner peripheral surface of the cylinder portion and the concave portion and the rear end shaft portion are By supplying pressure oil between the rear end faces and displacing the rear end shaft portion to the set position, the cylinder portion and the rear end shaft portion are brought into non-contact, and when the screw is driven forward, the supply of pressure oil is released and The screw support device for an injection molding machine according to the present invention is provided with a plurality of cylinder portions in the recess at the tip of the drive member, and the rear end of each screw by the cylinder portion. To support the shaft part so that it can be displaced in the axial direction. When the screw is driven to rotate, the gap between the outer peripheral surface of the rear end shaft portion and the inner peripheral surface of the cylinder portion and the pressure oil is supplied between the recess and the rear end surface of the rear end shaft portion to set the rear end shaft portion to the set position. A hydraulic circuit unit that brings the cylinder part and the rear end shaft part into non-contact by displacing the rear end part and releases the supply of pressure oil and abuts the rear end surface of the rear end shaft part in the recess when the screw is driven forward. Therefore, the reliability when the screw is supported by the driving member can be remarkably enhanced, and the remarkable effect that injection molding can be performed without being limited by the magnitude of the thrust load applied to the screw. Play.
[Brief description of the drawings]
FIG. 1 is a cross-sectional side view including a hydraulic circuit portion of a screw support device according to the present invention;
FIG. 2 is a development view of an inner peripheral surface of a cylinder portion constituting the screw support device;
FIG. 3 is a cross-sectional front view of a cylinder portion and a rear end shaft portion in the screw support device;
FIG. 4 is an enlarged sectional side view showing a main part of a screw support device of an injection molding machine according to the present invention;
FIG. 5 is an overall cross-sectional side view of an injection molding machine including the screw support device;
FIG. 6 is a sectional front view of a heating cylinder of the injection molding machine,
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Screw support device 2 Drive member 3x ... Screw 4x ... Cylinder part 5x ... Rear end shaft part 6 Hydraulic circuit part 7 Position sensor 8 Control part 21 Recessed part Ps Setting position Ssx Gap Sr ... Oil passage

Claims

In a screw support method for an injection molding machine that supports a plurality of screw screws arranged in parallel by a single drive member, a rear end shaft portion of each screw is provided by a plurality of cylinder portions provided in a recess at the tip of the drive member. The shaft is supported so as to be displaceable in the axial direction, and when the screw is driven to rotate, the clearance between the outer peripheral surface of the rear end shaft portion and the inner peripheral surface of the cylinder portion, and between the concave portion and the rear end surface of the rear end shaft portion. By supplying pressure oil and displacing the rear end shaft portion to a set position, the cylinder portion and the rear end shaft portion are brought into non-contact, and when the screw is driven forward, the supply of the pressure oil is released. A screw support method for an injection molding machine, wherein a rear end surface of the rear end shaft portion is brought into contact with the concave portion.

When pressure oil is supplied between the cylinder portion and the rear end shaft portion, the position of the rear end shaft portion in the axial direction is detected, and the pressure oil is adjusted so that the rear end shaft portion becomes the set position. 2. The screw support method for an injection molding machine according to claim 1, wherein the supply is controlled.

The screw support method for an injection molding machine according to claim 1, wherein the gap includes one or more spiral oil passages.

In a screw support device of an injection molding machine that supports a plurality of screws arranged in parallel by a single drive member, a plurality of cylinder portions are provided in a recessed portion at a tip of the drive member, and the rear end of each screw is provided by the cylinder portion. The shaft portion is supported so as to be displaceable in the axial direction, and when the screw is driven to rotate, the clearance between the outer peripheral surface of the rear end shaft portion and the inner peripheral surface of the cylinder portion, and the rear portion of the recess and the rear end shaft portion. By supplying pressure oil between the end faces and displacing the rear end shaft portion to a set position, the cylinder portion and the rear end shaft portion are brought into non-contact, and when the screw is driven forward, the pressure oil is supplied. A screw support device for an injection molding machine, comprising: a hydraulic circuit portion that is released to bring the rear end surface of the rear end shaft portion into contact with the recess.

5. The screw support device for an injection molding machine according to claim 4, wherein the driving member is an injection piston of an injection cylinder.

The hydraulic circuit portion includes a position sensor that detects a position of the rear end shaft portion in the axial direction, and when the hydraulic oil is supplied between the cylinder portion and the rear end shaft portion, the rear end shaft portion is The screw support device for an injection molding machine according to claim 4, further comprising a control unit that controls supply of the pressure oil so as to be in a set position.

The screw support device for an injection molding machine according to claim 4, wherein the gap includes one or more spiral oil passages.