JP3357303B2 - Backflow prevention device of metal injection molding machine - Google Patents
Backflow prevention device of metal injection molding machineInfo
- Publication number
- JP3357303B2 JP3357303B2 JP33023698A JP33023698A JP3357303B2 JP 3357303 B2 JP3357303 B2 JP 3357303B2 JP 33023698 A JP33023698 A JP 33023698A JP 33023698 A JP33023698 A JP 33023698A JP 3357303 B2 JP3357303 B2 JP 3357303B2
- Authority
- JP
- Japan
- Prior art keywords
- valve
- metal material
- screw
- molten metal
- backflow prevention
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Injection Moulding Of Plastics Or The Like (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、加熱シリンダとス
クリュとを有する射出成形機を用いて溶融金属材料を金
型のキャビティに射出し、保圧するとき、溶融金属材料
がスクリュの方へ逆流するのを防ぐための金属射出成形
機の逆流防止装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine having a heating cylinder and a screw, which injects a molten metal material into a cavity of a mold, and when the pressure is maintained, the molten metal material flows back toward the screw. The present invention relates to a backflow prevention device of a metal injection molding machine for preventing the occurrence of a backflow.
【０００２】[0002]
【従来の技術】金属材料の成形に使用されるインライン
スクリュ式の金属射出成形機は、加熱シリンダと、この
加熱シリンダ内で回転および軸方向に駆動されるスクリ
ュとから構成されている。このような金属射出成形機に
おいて溶融金属材料の逆流を防ぐための従来の逆流防止
装置は、図６に示すように、スクリュ１０２の先端に形
成された段差部等からなる押し金１０３と、スクリュヘ
ッド１０４と、両者の間を軸方向に往復移動自在である
逆流防止リング１０５を有する。押し金１０３の前端に
は、逆流防止リング１０５の後端面に設けられたシート
座１０５ａを当接させるためのシート面１０３ａが形成
されている。すなわち、逆流防止リング１０５は、押し
金１０３に対して相対的に軸方向に移動し、射出・保圧
時にシート座１０５ａを押し金１０３のシート面１０３
ａに当接してスクリュ側に溶融金属材料が逆流するのを
防ぐように構成されている。2. Description of the Related Art An in-line screw type metal injection molding machine used for molding a metal material includes a heating cylinder, and a screw which is rotated and axially driven in the heating cylinder. As shown in FIG. 6, a conventional backflow prevention device for preventing a backflow of a molten metal material in such a metal injection molding machine includes a presser 103 having a step portion formed at the tip of a screw 102 and a screw 103. It has a head 104 and a backflow prevention ring 105 that is reciprocally movable in the axial direction between them. At the front end of the pusher 103, a seat surface 103a for abutting a seat 105a provided on the rear end surface of the backflow prevention ring 105 is formed. That is, the backflow prevention ring 105 moves in the axial direction relatively to the pusher 103, and pushes the seat 105a to the seat surface 103 of the pusher 103 during injection and pressure holding.
a to prevent the molten metal material from flowing back to the screw side.
【０００３】スクリュ１０２を回転駆動して金属材料を
撹拌・溶融するときは、逆流防止リング１０５のシート
座１０５ａが押し金１０３のシート面１０３ａから離間
し、溶融金属材料の通過を許容して、スクリュヘッド１
０４の前方すなわち加熱シリンダ１０１の前室１０１ａ
に蓄積することができる。また、スクリュ１０２を軸方
向に駆動して溶融金属材料を金型内に射出し、そして保
圧するきときは、逆流防止リング１０５のシート座１０
５ａが押し金１０３のシート面１０３ａに当接して、溶
融金属材料がスクリュ１０２の方向へ逆流することが阻
止される。When the screw 102 is driven to rotate to agitate / melt the metal material, the seat 105a of the backflow prevention ring 105 is separated from the sheet surface 103a of the pusher 103 to allow the molten metal material to pass therethrough. Screw head 1
04, that is, the front chamber 101a of the heating cylinder 101
Can be accumulated. Further, when the screw 102 is driven in the axial direction to inject the molten metal material into the mold and to maintain the pressure, the seat 10 of the backflow prevention ring 105 is used.
5 a comes into contact with the sheet surface 103 a of the pusher 103, and the molten metal material is prevented from flowing backward in the direction of the screw 102.
【０００４】逆流防止リング１０５の外周面と加熱シリ
ンダ１０１の内周面との隙間から溶融金属材料が逆流す
るのを防ぐために、逆流防止リング１０５の外径は、円
滑な摺動が可能な範囲で最大径に設定されている。In order to prevent the molten metal material from flowing back through a gap between the outer peripheral surface of the backflow prevention ring 105 and the inner peripheral surface of the heating cylinder 101, the outer diameter of the backflow prevention ring 105 is set within a range where smooth sliding is possible. Is set to the maximum diameter.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら従来の技
術によれば、射出工程でスクリュ１０２が前進すると、
背圧によって逆流防止リング１０５が相対的に後退し
て、押し金１０３のシート面１０３ａが逆流防止リング
１０５のシート座１０５ａに当接され、溶融材料がスク
リュ１０２の方向へ逆流することが阻止されるものであ
るため、例えば樹脂材料のように溶融状態で比較的粘度
が高い材料を射出・保圧する場合には、スクリュ方向へ
の逆流を阻止するのに実用上問題ないが、金属材料のよ
うに溶融粘度が極めて低い溶融材料を射出および保圧す
る場合には、押し金１０３のシート面１０３ａが逆流防
止リング１０５のシート座１０５ａに当接するまでの短
時間内に、両者のわずかな隙間を通って多量の溶融金属
材料がスクリュ１０２の方向へ逆流する。However, according to the prior art, when the screw 102 advances in the injection process,
The backflow prevention ring 105 relatively retreats due to the back pressure, and the seat surface 103a of the pusher 103 comes into contact with the seat 105a of the backflow prevention ring 105, thereby preventing the molten material from flowing back in the direction of the screw 102. Therefore, for example, when injecting and holding a material having a relatively high viscosity in a molten state such as a resin material, there is no practical problem in preventing backflow in the screw direction. When a molten material having an extremely low melt viscosity is injected and dwelled, the sheet surface 103a of the pusher 103 passes through a slight gap between the two within a short time until the sheet surface 103a contacts the seat 105a of the backflow prevention ring 105. As a result, a large amount of molten metal material flows back toward the screw 102.
【０００６】このような逆流は、計量された溶融金属材
料の全量が金型のキャビティに射出されないという結果
を招き、加えて保圧力も小さくなるため、設定された成
形条件が得られず、ヒケ、ボイド等の成形欠陥を生ず
る。[0006] Such a backflow causes a result that the entire amount of the measured molten metal material is not injected into the cavity of the mold. In addition, the holding pressure becomes small, so that the set molding conditions cannot be obtained, and And molding defects such as voids.
【０００７】また、特に樹脂材料の射出成形装置におい
ては、図７に示すように、スクリュ１１２の外周面から
軸心穴１１２ａに通ずる流通路１１２ｂを設けるととも
に、スクリュ１１２の先端に取り付けられたスクリュヘ
ッド１１４に軸心穴１１４ａと弁室１１４ｂを設けて、
弁室１１４ｂ内に球形弁１１４ｃを挿入し、コイルバネ
１１４ｄにより球形弁１１４ｃをスクリュ１１２の先端
の弁座１１２ｃに押しつけて、軸心穴１１２ａを閉鎖す
る方式の逆流防止装置が開発されている。この方式は、
流路幅が小さくて、シールが容易になるので、より一層
確実な逆流防止効果が得られるが、金属材料のように数
百度の高温状態の溶融材料の場合には、コイルバネ等の
弾性部材が短期間でクリープ変形を生じて押圧力が低下
し、逆流防止機能が失われる。従って、金属射出成形機
の逆流防止装置には適用できない。In particular, in a resin material injection molding apparatus, as shown in FIG. 7, a flow passage 112b is provided from the outer peripheral surface of the screw 112 to the shaft hole 112a, and a screw attached to the tip of the screw 112 is provided. By providing an axial hole 114a and a valve chamber 114b in the head 114,
A backflow prevention device has been developed in which a spherical valve 114c is inserted into a valve chamber 114b, and the spherical valve 114c is pressed against a valve seat 112c at the tip of a screw 112 by a coil spring 114d to close a shaft hole 112a. This method is
Since the flow passage width is small and sealing is easy, a more reliable backflow prevention effect can be obtained.However, in the case of a molten material in a high temperature state of several hundred degrees, such as a metal material, an elastic member such as a coil spring is used. Creep deformation occurs in a short period of time, the pressing force decreases, and the backflow prevention function is lost. Therefore, it cannot be applied to a backflow prevention device of a metal injection molding machine.
【０００８】本発明は上記従来の技術の有する未解決の
課題に鑑みてなされたものであり、弁体の着座が迅速か
つ確実に行なわれ、しかも構造が簡単であり、計量され
た溶融金属材料がスクリュの方へ逆流するのを極めて効
果的に防ぐことのできる金属射出成形機の逆流防止装置
を提供することを目的とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems in the prior art, and has a simple and simple structure in which a valve element can be seated, and has a simple structure. It is an object of the present invention to provide a backflow prevention device for a metal injection molding machine, which can extremely effectively prevent backflow from flowing toward a screw.
【０００９】[0009]
【課題を解決するための手段】上記目的を達成するため
に本発明の金属射出成形機の逆流防止装置は、加熱シリ
ンダ内に配設されたスクリュと一体であるスクリュヘッ
ドの軸心穴の開口端に配設された弁座と、前記スクリュ
ヘッドの前記軸心穴に連通する弁室と、該弁室内に遊動
自在に配設された弁体を有し、該弁体の比重が、前記ス
クリュによって前記軸心穴から前記弁室に供給される溶
融金属材料の比重より大であり、前記弁体が自重によっ
て前記弁座に着座することで前記溶融金属材料の逆流を
防ぐように構成されていることを特徴とする。According to the present invention, there is provided a backflow preventing apparatus for a metal injection molding machine according to the present invention, wherein an opening in an axial hole of a screw head integrated with a screw disposed in a heating cylinder is provided. A valve seat disposed at an end, a valve chamber communicating with the shaft hole of the screw head, and a valve element movably disposed in the valve chamber, wherein the specific gravity of the valve element is The specific gravity of the molten metal material supplied from the axial hole to the valve chamber by a screw is larger than the specific gravity of the molten metal material, and the valve body is configured to prevent backflow of the molten metal material by sitting on the valve seat by its own weight. It is characterized by having.
【００１０】弁体が、弁室の前端部に配設された円錐穴
に嵌合する円錐面と、弁座に当接自在であるシート面を
有するとよい。[0010] It is preferable that the valve body has a conical surface that fits into a conical hole provided at the front end of the valve chamber, and a seat surface that can freely contact the valve seat.
【００１１】弁室の円錐穴に放射状の溝が設けられてい
るとよい。Preferably, a radial groove is provided in the conical hole of the valve chamber.
【００１２】弁体の円錐面に放射状の溝が設けられてい
てもよい。A radial groove may be provided on the conical surface of the valve body.
【００１３】弁座および弁体の少なくとも一方にシート
部材が取り付けられているとよい。It is preferable that a seat member is attached to at least one of the valve seat and the valve body.
【００１４】[0014]
【作用】スクリュによって加熱シリンダの前室に溶融金
属材料を供給し、計量する工程では、溶融金属材料がス
クリュヘッドの軸心穴から弁室へ流入し、溶融金属材料
の供給圧力によって弁体を弁座から離間させた状態に維
持する。In the step of supplying the molten metal material to the front chamber of the heating cylinder by the screw and measuring the molten metal material, the molten metal material flows into the valve chamber from the axial hole of the screw head, and the valve body is supplied by the supply pressure of the molten metal material. Maintain separated from valve seat.
【００１５】計量工程が終了し、溶融金属材料の供給が
停止して溶融金属材料の供給圧力が無くなると、弁体が
自重によって降下し、弁座に着座する。When the supply of the molten metal material is stopped and the supply pressure of the molten metal material is lost after the measurement step is completed, the valve body descends by its own weight and sits on the valve seat.
【００１６】射出工程においては、溶融金属材料が金型
に射出されるときの背圧によって弁体が弁座に押しつけ
られて密着するため、溶融金属材料の逆流を確実に防ぐ
ことができる。In the injection step, since the valve element is pressed against the valve seat by the back pressure when the molten metal material is injected into the mold and comes into close contact with the valve seat, backflow of the molten metal material can be reliably prevented.
【００１７】計量工程の終了と同時に弁体が自重によっ
て降下して弁座に着座する構成であるため、弁体の着座
が迅速かつ確実であり、溶融金属材料の逆流を完全に防
ぐことができる。Since the valve body is lowered by its own weight and seated on the valve seat at the same time as the completion of the measuring step, the seating of the valve body is quick and reliable, and the backflow of the molten metal material can be completely prevented. .
【００１８】弁体の自重等によって弁の開閉を自動的に
行なうものであるから、コイルバネ等の弾性部材を必要
とせず、従って、構造が極めて簡単であり、その結果、
長寿命でしかも安価であるという長所もある。Since the valve is automatically opened and closed by the weight of the valve body, no elastic member such as a coil spring is required. Therefore, the structure is extremely simple.
It also has the advantage of long life and low cost.
【００１９】[0019]
【発明の実施の形態】本発明の実施の形態を図面に基づ
いて説明する。Embodiments of the present invention will be described with reference to the drawings.
【００２０】図１は一実施の形態を示すもので、これ
は、金属射出成形機の加熱シリンダ１内に回転および前
後進自在に挿入されたスクリュ２の先端にねじ部２ａに
よって取り付けられたスクリュヘッド３と、スクリュヘ
ッド３の前部に螺着されたヘッドカバー４を有し、スク
リュヘッド３とヘッドカバー４との間には弁室５が形成
され、弁室５内には弁体６が遊動自在に配設されてい
る。FIG. 1 shows an embodiment in which a screw 2 is attached to a tip end of a screw 2 inserted into a heating cylinder 1 of a metal injection molding machine so as to rotate and move forward and backward by a screw portion 2a. It has a head 3 and a head cover 4 screwed to the front of the screw head 3, and a valve chamber 5 is formed between the screw head 3 and the head cover 4, and a valve element 6 floats in the valve chamber 5. It is arranged freely.
【００２１】スクリュヘッド３の最大外径部３ａは、加
熱シリンダ１との隙間が最小、すなわちスクリュヘッド
３の回転および前後進が可能な範囲で最大となる外径を
有し、最大外径部３ａに設けられた溝には、ピストンリ
ング等のシールリングＳが挿入されている。スクリュヘ
ッド３の最大外径部３ａよりスクリュ２側には、その外
周面から軸心に向けて複数の流通路３ｂが設けられ、ス
クリュヘッド３の前端からスクリュ２側に向けて設けら
れた軸心穴３ｃと合流している（図２の（ｂ）参照）。
スクリュヘッド３の軸心穴３ｃの開口端には、軸心に対
して垂直な平面状の弁座３ｄが形成されている。The maximum outer diameter portion 3a of the screw head 3 has an outer diameter that minimizes the gap with the heating cylinder 1, that is, the maximum outer diameter in a range where the screw head 3 can rotate and move back and forth. A seal ring S such as a piston ring is inserted into a groove provided in 3a. A plurality of flow passages 3b are provided on the screw 2 side from the maximum outer diameter portion 3a of the screw head 3 toward the axis from the outer peripheral surface thereof, and a shaft provided from the front end of the screw head 3 toward the screw 2 side. It merges with the core hole 3c (see FIG. 2B).
At the opening end of the shaft hole 3c of the screw head 3, a planar valve seat 3d perpendicular to the axis is formed.
【００２２】ヘッドカバー４は、スクリュヘッド３の前
部に螺着され、ヘッドカバー４の前部の軸心穴４ａと後
部の弁室５との接続部すなわち弁室５の前端部には、軸
心穴４ａと同軸の円錐穴４ｂが形成され、弁体６の円錐
面６ａが嵌合している。The head cover 4 is screwed to the front part of the screw head 3, and a connecting part between the front axial hole 4 a of the head cover 4 and the rear valve chamber 5, that is, the front end of the valve chamber 5 has an axial center. A conical hole 4b coaxial with the hole 4a is formed, and a conical surface 6a of the valve body 6 is fitted.
【００２３】図２の（ａ）に示すように、ヘッドカバー
４の円錐穴４ｂは、その円錐状の壁面に複数の放射状の
溝４ｃを有し、弁体６の円錐面６ａ全体がヘッドカバー
４の円錐穴４ｂに密着した状態でも、弁室５内の溶融金
属材料が軸心穴４ａを通って加熱シリンダ１の前室１ａ
に流入できるように構成されている（図３参照）。As shown in FIG. 2A, the conical hole 4b of the head cover 4 has a plurality of radial grooves 4c on its conical wall surface. Even when the molten metal material is in close contact with the conical hole 4b, the molten metal material in the valve chamber 5 passes through the axial hole 4a and the front chamber 1a of the heating cylinder 1
(See FIG. 3).
【００２４】弁体６は、溶融金属材料より比重が大きく
て、溶融金属材料の温度で溶融および変形しない材料で
作られており、前部に円錐面６ａ、後端に軸心と垂直な
シート面６ｂを有する略円筒形状をなし、弁室５内で径
方向と軸方向に移動自在に配設されている（図２の
（ａ）参照）。The valve body 6 has a specific gravity greater than that of the molten metal material and is made of a material that does not melt and deform at the temperature of the molten metal material. A conical surface 6a is provided at the front and a sheet perpendicular to the axis is provided at the rear end. It has a substantially cylindrical shape having a surface 6b, and is disposed movably in the radial direction and the axial direction in the valve chamber 5 (see FIG. 2A).
【００２５】計量工程において、スクリュ２が回転駆動
されると、溶融金属材料がスクリュ溝２ｂの中を加熱シ
リンダ１の前室１ａに向かって搬送される。溶融金属材
料は、スクリュヘッド３の流通路３ｂを経て、軸心穴３
ｃを通り、次いで、スクリュヘッド３の前端の弁座３ｄ
と弁体６のシート面６ｂとの隙間、弁室５、ヘッドカバ
ー４の円錐穴４ｂと弁体６の円錐面６ａとの隙間すなわ
ち溝４ｃ、ヘッドカバー４の軸心穴４ａの順に通過し
て、加熱シリンダ１の前室１ａに流入し、蓄積される。In the measuring step, when the screw 2 is driven to rotate, the molten metal material is conveyed through the screw groove 2b toward the front chamber 1a of the heating cylinder 1. The molten metal material passes through the flow passage 3b of the screw head 3 and passes through the axial hole 3b.
c, and then the valve seat 3d at the front end of the screw head 3
Through the gap between the valve body 5 and the seat surface 6b of the valve body 6, the valve chamber 5, the gap between the conical hole 4b of the head cover 4 and the conical surface 6a of the valve body 6, that is, the groove 4c, and the axial hole 4a of the head cover 4, in that order. It flows into the front chamber 1a of the heating cylinder 1 and is accumulated.
【００２６】計量工程が終了し、スクリュ２の回転が停
止され、スクリュ溝２ｂから加熱シリンダ１の前室１ａ
への溶融金属材料の供給が終わると、スクリュヘッド３
の軸心穴３ｃから弁室５に向かう溶融金属材料の流れが
停止するため、溶融金属材料より重い弁体６が自重によ
って降下する。このとき弁体６は、ヘッドカバー４の円
錐穴４ｂに沿って軸心から離れながら後退し、自重によ
ってスクリュヘッドの弁座３ｄに着座して軸心穴３ｃを
塞ぐ。The metering process is completed, the rotation of the screw 2 is stopped, and the screw chamber 2b is moved from the screw chamber 2b to the front chamber 1a
When the supply of the molten metal material to the
The flow of the molten metal material from the axial hole 3c toward the valve chamber 5 stops, so that the valve 6 that is heavier than the molten metal material descends by its own weight. At this time, the valve element 6 retreats away from the axis along the conical hole 4b of the head cover 4, and sits on the valve seat 3d of the screw head by its own weight to close the axis hole 3c.
【００２７】続く射出工程においては、スクリュ２が前
方へ駆動され、加熱シリンダ１の前室１ａに蓄積された
溶融金属材料が、ノズル穴１ｂを通過して図示しない金
型のキャビティに射出される。このとき、加熱シリンダ
１の前室１ａ内における溶融金属材料の圧力が上昇する
ため、前室１ａ内に蓄積された溶融金属材料の一部が、
弁室５を通ってスクリュ２の方向に逆流しようとする
が、すでに弁体６のシート面６ｂがスクリュヘッド３の
弁座３ｄに当接して軸心穴３ｃを塞いでおり、さらに、
弁室５内の溶融金属材料の圧力（背圧）により弁体６が
スクリュヘッド３に押しつけられて弁座３ｄに密着する
ため、溶融金属材料の逆流が確実に阻止される。In the subsequent injection step, the screw 2 is driven forward, and the molten metal material accumulated in the front chamber 1a of the heating cylinder 1 is injected into the mold cavity (not shown) through the nozzle hole 1b. . At this time, since the pressure of the molten metal material in the front chamber 1a of the heating cylinder 1 increases, a part of the molten metal material accumulated in the front chamber 1a
Although it is going to flow backward in the direction of the screw 2 through the valve chamber 5, the seat surface 6b of the valve body 6 has already contacted the valve seat 3d of the screw head 3 to close the shaft hole 3c.
The valve element 6 is pressed against the screw head 3 by the pressure (back pressure) of the molten metal material in the valve chamber 5 and comes into close contact with the valve seat 3d, so that the backflow of the molten metal material is reliably prevented.
【００２８】スクリュヘッド３の最大外径部３ａは、ス
クリュヘッド３の回転および前後進が可能な範囲で、加
熱シリンダ１との隙間が最小になるように設定され、さ
らに外周面に設けられた溝にシールリングＳが挿入され
ているので、スクリュヘッド３と加熱シリンダ１との隙
間から溶融金属材料が逆流することはない。The maximum outer diameter portion 3a of the screw head 3 is set so as to minimize the gap between the screw cylinder 3 and the heating cylinder 1 as long as the screw head 3 can rotate and move forward and backward, and is provided on the outer peripheral surface. Since the seal ring S is inserted into the groove, the molten metal material does not flow backward from the gap between the screw head 3 and the heating cylinder 1.
【００２９】なお、ヘッドカバー４の円錐穴４ｂには、
前述のように、放射状の溝４ｃが設けられているため、
計量工程において溶融金属材料の流量が多く、弁体６が
ヘッドカバー４の円錐穴４ｂに当接した状態でも、溶融
金属材料の流路が確保される。In the conical hole 4b of the head cover 4,
As described above, since the radial groove 4c is provided,
In the measuring step, even when the flow rate of the molten metal material is large and the valve element 6 is in contact with the conical hole 4b of the head cover 4, a flow path of the molten metal material is secured.
【００３０】図４は一変形例を示す。これは、図１の装
置のヘッドカバー４の円錐穴４ｂに放射状の溝４ｃを設
ける替わりに、弁体１６の円錐面１６ａに放射状の溝１
６ｃを設けたものであり、溝１６ｃの加工や清掃が容易
であるという利点がある。FIG. 4 shows a modification. This is because instead of providing the radial groove 4c in the conical hole 4b of the head cover 4 of the apparatus of FIG. 1, the radial groove 1c is formed in the conical surface 16a of the valve body 16.
6c, which is advantageous in that processing and cleaning of the groove 16c are easy.
【００３１】図５はさらに別の変形例を示す。これは、
スクリュヘッド３の先端部の弁座３ｄと、弁体６のシー
ト面６ｂのいずれか一方または両方に、シート部材２７
を取り付けたものである。このようなシート部材２７を
介在させることにより、当接部のシール性を強化し、当
接強度を向上させるとともに、損傷時における部品の交
換も容易になる。FIG. 5 shows another modification. this is,
A seat member 27 is attached to one or both of the valve seat 3d at the distal end of the screw head 3 and the seat surface 6b of the valve body 6.
Is attached. By interposing such a sheet member 27, the sealing property of the contact portion is strengthened, the contact strength is improved, and replacement of parts in the event of damage is facilitated.
【００３２】本発明は、上記の形態に限定されることな
く様々な変更が自在である。例えば、弁体の前端を円錐
形にする替わりに、その最先端部をなくした円錐台に形
成してもよい。また、溶融金属材料の粘度が比較的高い
場合には、スクリュヘッドの外周面に設けたシールリン
グを省略することもできる。The present invention is not limited to the above-described embodiment, but can be variously modified. For example, instead of forming the front end of the valve body into a conical shape, the valve body may be formed into a truncated cone without the leading end. When the viscosity of the molten metal material is relatively high, the seal ring provided on the outer peripheral surface of the screw head can be omitted.
【００３３】さらに、上記の形態における弁体は、充分
な自重と強度を確保するために、円筒形の胴部を設けた
が、大型機等に使用される場合には、弁体が重くなり過
ぎて敏感な作動が困難になる可能性がある。その場合に
は円筒形の胴部を持たない円錐形の弁体にすることもで
きる。Further, the valve body in the above-mentioned embodiment has a cylindrical body in order to secure a sufficient weight and strength, but when used in a large machine or the like, the valve body becomes heavy. Too sensitive and difficult to operate. In this case, a conical valve body having no cylindrical body may be used.
【００３４】また、上記の形態においては、スクリュヘ
ッドの先端部、弁体の後端部のいずれか一方または両方
にシート部材を取り付けたが、これに替えて、スクリュ
ヘッドの先端部の弁座、弁体後端のシート面のいずれか
一方または両方に表面処理を施したり、別の部材を溶着
させたりしたものでもよい。In the above embodiment, the seat member is attached to one or both of the distal end of the screw head and the rear end of the valve body. Alternatively, a valve seat at the distal end of the screw head may be used. The surface treatment may be applied to one or both of the seat surfaces at the rear end of the valve body, or another member may be welded.
【００３５】以上のように、本発明による逆流防止装置
は、スクリュヘッド、ヘッドカバーおよび弁体とからな
る簡単な構造であり、自重による弁体の着座も確実であ
るので、溶融金属材料に対して極めて信頼性の高い逆流
防止機能を有する。As described above, the backflow prevention device according to the present invention has a simple structure including the screw head, the head cover, and the valve element, and the valve element can be securely seated by its own weight. It has an extremely reliable backflow prevention function.
【００３６】加えて、スクリュの回転すなわち計量が終
了するとほぼ同時に、弁体がスクリュヘッドの弁座に着
座して流路を閉鎖するので、射出工程における溶融金属
材料の逆流が完全に防止できる。すなわち、計量された
溶融金属材料の全量が金型のキャビティに射出され、ま
た保圧力も小さくならないので、設定された通りの成形
条件が得られる。従って、溶融金属材料の逆流によるヒ
ケ、ボイト等の成形欠陥の発生を防ぐことができる。In addition, the valve body is seated on the valve seat of the screw head and closes the flow passage almost at the same time when the rotation or the metering of the screw is completed, so that the backflow of the molten metal material in the injection step can be completely prevented. That is, the entire amount of the measured molten metal material is injected into the cavity of the mold, and the holding pressure does not decrease, so that the set molding conditions can be obtained. Therefore, the occurrence of molding defects such as sink marks and voids due to the backflow of the molten metal material can be prevented.
【００３７】さらに、コイルバネ等の弾性部材により球
形弁を弁座に押しつけて流路を閉鎖する方式の逆流防止
装置のように、数百度の高温状態にさらされた弾性部材
が短期間でクリープ変形を生じ、押圧力が低下して逆流
防止機能を失う等の問題もない。Further, an elastic member exposed to a high temperature of several hundred degrees is creep-deformed in a short period of time, such as a backflow prevention device in which a spherical valve is pressed against a valve seat by an elastic member such as a coil spring to close a flow passage. And there is no problem that the pressing force is reduced and the backflow prevention function is lost.
【００３８】また、弁の開閉のために外部から駆動力を
必要としないので、機構が簡単であり、駆動力伝達部分
から溶融金属材料が漏出して、トラブルを生ずるような
こともない。Further, since no external driving force is required for opening and closing the valve, the mechanism is simple, and there is no possibility that the molten metal material leaks from the driving force transmitting portion to cause trouble.
【００３９】ヘッドカバーの円錐穴または弁体の円錐面
に放射状の溝が設けられているので、弁体がヘッドカバ
ーの円錐穴に当接した場合にも、溶融金属材料の流路が
確保される。Since the radial groove is provided in the conical hole of the head cover or the conical surface of the valve body, the flow path of the molten metal material is secured even when the valve body comes into contact with the conical hole of the head cover.
【００４０】なお、スクリュ回転時に、弁体が弁室内で
偏心回転するが、弁体と弁室壁との間には溶融金属材料
が介在するので、摩耗等を生ずることはない。弁体が偏
心回転するため、弁体が特定の位置に固定されることが
なく、弁体の偏心回転によって弁室内が清掃されるとい
う効果も生ずる。During rotation of the screw, the valve element rotates eccentrically in the valve chamber. However, since the molten metal material is interposed between the valve element and the valve chamber wall, wear does not occur. Since the valve element rotates eccentrically, the valve element is not fixed at a specific position, and the valve chamber is cleaned by the eccentric rotation of the valve element.
【００４１】その結果、粘度が極めて低く、かつ高温の
溶融金属材料を長期間安定的に成形することのできる金
属射出成形機を実現できる。As a result, a metal injection molding machine having a very low viscosity and capable of forming a high-temperature molten metal material stably for a long period of time can be realized.
【００４２】[0042]
【発明の効果】本発明は上述のように構成されているの
で、以下に記載するような効果を奏する。Since the present invention is configured as described above, it has the following effects.
【００４３】逆流防止装置の弁体の着座が迅速かつ確実
であり、しかも構造が簡単で、計量された溶融金属材料
がスクリュの方へ逆流するのを極めて効果的に防ぐこと
ができる。The seating of the valve body of the backflow prevention device is quick and reliable, the structure is simple, and the backflow of the measured molten metal material toward the screw can be extremely effectively prevented.
【００４４】このような逆流防止装置を搭載すること
で、高温で粘度の低い溶融金属材料の射出成形を長期間
安定的に行なうことのできる安価で高性能な金属射出成
形機を実現できる。By mounting such a backflow prevention device, an inexpensive and high-performance metal injection molding machine capable of stably performing a long-term stable injection molding of a molten metal material having a low viscosity at a high temperature can be realized.
【図１】一実施の形態による金属射出成形機の逆流防止
装置を示す模式断面図である。FIG. 1 is a schematic sectional view showing a backflow prevention device of a metal injection molding machine according to one embodiment.
【図２】図１の装置の径方向の断面を示すもので、
（ａ）は図１のＡ−Ａ線に沿ってとった断面図、（ｂ）
はＢ−Ｂ線に沿ってとった断面図である。FIG. 2 shows a radial section of the device of FIG. 1;
(A) is a sectional view taken along the line AA of FIG. 1, (b)
FIG. 4 is a cross-sectional view taken along line BB.
【図３】図１の装置の弁動作を説明するもので、（ａ）
は弁室を含む部分断面図、（ｂ）は（ａ）のＣ−Ｃ線に
沿ってとった断面図である。FIG. 3 illustrates the valve operation of the device of FIG. 1;
FIG. 2 is a partial sectional view including a valve chamber, and FIG. 2B is a sectional view taken along line CC of FIG.
【図４】一変形例を示す図である。FIG. 4 is a diagram showing a modification.
【図５】別の変形例を示す図である。FIG. 5 is a diagram showing another modification.
【図６】一従来例を示す模式断面図である。FIG. 6 is a schematic sectional view showing a conventional example.
【図７】別の従来例を示す模式断面図である。FIG. 7 is a schematic sectional view showing another conventional example.
１ 加熱シリンダ １ａ 前室 ２ スクリュ ２ｂ スクリュ溝 ３ スクリュヘッド ３ｃ，４ａ 軸心穴 ３ｄ 弁座 ４ ヘッドカバー ４ｂ 円錐穴 ４ｃ，１６ｃ 溝 ５ 弁室 ６，１６ 弁体 ６ａ，１６ａ 円錐面 ６ｂ シート面 ２７ シート部材 DESCRIPTION OF SYMBOLS 1 Heating cylinder 1a Front chamber 2 Screw 2b Screw groove 3 Screw head 3c, 4a Shaft hole 3d Valve seat 4 Head cover 4b Conical hole 4c, 16c Groove 5 Valve chamber 6, 16 Valve body 6a, 16a Conical surface 6b Seat surface 27 seat Element
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平９−11291（ＪＰ，Ａ) 特開2000−117410（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B22D 17/20 B29C 45/52 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-11291 (JP, A) JP-A-2000-117410 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B22D 17/20 B29C 45/52
Claims (5)
リュ（２）と一体であるスクリュヘッド（３）の軸心穴
（３ｃ）の開口端に配設された弁座（３ｄ）と、前記ス
クリュヘッドの前記軸心穴に連通する弁室（５）と、該
弁室内に遊動自在に配設された弁体（６，１６）を有
し、該弁体の比重が、前記スクリュによって前記軸心穴
から前記弁室に供給される溶融金属材料の比重より大で
あり、前記弁体が自重によって前記弁座に着座すること
で前記溶融金属材料の逆流を防ぐように構成されている
ことを特徴とする金属射出成形機の逆流防止装置。1. A valve seat (3d) disposed at an open end of a shaft hole (3c) of a screw head (3) integral with a screw (2) disposed in a heating cylinder (1). A valve chamber (5) communicating with the shaft hole of the screw head, and valve bodies (6, 16) movably disposed in the valve chamber, wherein the specific gravity of the valve body is The specific gravity of the molten metal material supplied from the axial hole to the valve chamber is larger than the specific gravity of the molten metal material, and the valve body is configured to prevent backflow of the molten metal material by sitting on the valve seat by its own weight. A backflow prevention device for a metal injection molding machine.
穴（４ｂ）に嵌合する円錐面（６ａ，１６ａ）と、弁座
に当接自在であるシート面（６ｂ）を有することを特徴
とする請求項１記載の金属射出成形機の逆流防止装置。2. A conical surface (6a, 16a) in which a valve element fits into a conical hole (4b) provided at a front end of a valve chamber, and a seat surface (6b) freely contactable with a valve seat. The backflow prevention device for a metal injection molding machine according to claim 1, further comprising:
けられていることを特徴とする請求項２記載の金属射出
成形機の逆流防止装置。3. A backflow prevention device for a metal injection molding machine according to claim 2, wherein a radial groove (4c) is provided in a conical hole of the valve chamber.
（１６ｃ）が設けられていることを特徴とする請求項２
記載の金属射出成形機の逆流防止装置。4. A radial groove (16c) is provided in the conical surface (16a) of the valve body.
A backflow prevention device for a metal injection molding machine as described in the above.
ト部材（２７）が取り付けられていることを特徴とする
請求項１ないし４いずれか１項記載の金属射出成形機の
逆流防止装置5. A backflow prevention device for a metal injection molding machine according to claim 1, wherein a seat member is attached to at least one of the valve seat and the valve body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33023698A JP3357303B2 (en) | 1998-11-05 | 1998-11-05 | Backflow prevention device of metal injection molding machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33023698A JP3357303B2 (en) | 1998-11-05 | 1998-11-05 | Backflow prevention device of metal injection molding machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000141009A JP2000141009A (en) | 2000-05-23 |
| JP3357303B2 true JP3357303B2 (en) | 2002-12-16 |
Family
ID=18230393
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33023698A Expired - Fee Related JP3357303B2 (en) | 1998-11-05 | 1998-11-05 | Backflow prevention device of metal injection molding machine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3357303B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7353858B2 (en) * | 2006-05-17 | 2008-04-08 | Husky Injection Molding Systems Ltd. | Cap for servicing molding-system valve |
| KR101082042B1 (en) * | 2009-04-02 | 2011-11-10 | 대구텍 유한회사 | Cutting insert for dual purpose of roughing and finishing |
-
1998
- 1998-11-05 JP JP33023698A patent/JP3357303B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000141009A (en) | 2000-05-23 |
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