JP4659286B2

JP4659286B2 - Cylindrical molded product injection mold and injection molding method

Info

Publication number: JP4659286B2
Application number: JP2001214083A
Authority: JP
Inventors: 広志米久保; 逸勇唐澤
Original assignee: Olympus Corp
Current assignee: Olympus Corp
Priority date: 2001-07-13
Filing date: 2001-07-13
Publication date: 2011-03-30
Anticipated expiration: 2021-07-13
Also published as: JP2003025389A

Description

【０００１】
【発明の属する技術分野】
本発明は、円筒形状の成形品を精度よく成形するための射出成形型および射出成形方法に関する。
【０００２】
【従来の技術】
例えば、円筒成形品の射出成形型として、内周面にヘリコイドネジ等のアンダーカットを有する成形品を成形するための射出成形型が特公昭５９−１４３３３号公報に開示されている。図１６〜図２０を用いてこの従来技術を説明する。図１６および図１７において、上部側の傾斜角度が交互に異なっている錐形の外面を備えたコア棒１０１の周囲には、第１スライド部材１０２および第２スライド部材１０３が交互にしかも軸心方向に摺動自在に配置されており、これらスライド部材の上端外周側には所望するヘリコイド形状のアンダーカット形状が彫り込まれた構成になっている。
【０００３】
つぎに、上記構成のコア棒を備えた射出成形型の射出成形時の作動について説明する。射出成形作業の際には、図１８に示すように、成形型１０７が閉じられて可動側金型１０５と固定側金型１０６とが閉じ合わされて、これらの間の空間部（キャビティ）にノズル１０９を通して成形材料が射出され射出成形品１０８が形成される。成形後に成形型１０７が開かれた後に、すなわち可動側金型１０５と固定側金型１０６とが相離されて射出成形品１０８の外周面が露出したのちに、図１９に示すように、最初に基板１５１に対して板１５２、１５３、１５４が行程Ｓだけ型開き方向に動かされると、コア棒１０１は基板１５１に固定されているので、コア棒１０１の錐形の外面に沿って、第２スライド部材１０３および第１スライド部材１０２が動く、即ち、コア棒１０１に対し相対的に第１スライド部材１０２および第２スライド部材１０３が型開き方向に摺動するとともに、コア棒１０１の軸心に向けて動く。これにより、射出成形品１０８の内周部より第１スライド部材１０２および第２スライド部材１０３のアンダーカット形状が半径中心方向に移動して離脱し、図２０に示すように、板１５３に対して板１５４を上昇させると、射出成形品１０８が取り出し可能となる。
【０００４】
これにより、内周部に複雑なヘリコイドネジやカム溝等のアンダーカットを自由に付加することが可能となり、射出成形品へのアンダーカット作成のための２次加工が不要で、安価で安定した生産が可能となるというものである。
【０００５】
【発明が解決しようとする課題】
しかるに、上記従来技術にはつぎのような問題点があった。すなわち、上記従来技術では、コア棒１０１の周囲に配置されたスライド部材１０２、１０３により内周部にアンダーカットが形成された射出成形品を成形した後に、可動側金型と固定側金型とをパーティングラインに沿って分離して成形型を開き、ついで各スライド部材１０２、１０３を移動するようになっている。この際、樹脂材料を用いた射出成形の場合、射出充填時に射出成形品に十分な圧力を与え、圧力保持したまま樹脂を冷却する。冷却によって射出成形品は体積収縮しようとするが、中心部にコア棒や第１スライド部材や第２スライド部材等のコア部材が存在するため収縮できず、射出成形品の外周部を成形する固定側金型の内周面を強く押し付けた状態（すなわち、射出成形品に内部ひずみが発生した状態）となっている。従って、そのまま成形型を開くと、射出成形品の外周部を形成する成形型の内周面によって、射出成形品の外周部にはキズや変形などのいわゆる「とられ」が発生してしまい、外観品質を損なうという問題点があった。
【０００６】
また、そのような「とられ」を発生させないために成形品に与える射出成形機側の圧力設定を小さくすると、「とられ」の問題は低減するが完全に解消できるものではなく、また、射出成形機側の圧力設定を小さくしすぎると、射出成形品に「ヒケ」が発生したり、成形収縮率の異方性が発生し、真円度、円筒度などの形状精度を悪化させてしまうので、量産においての品質のばらつきの原因にもなっていた。また、成形型内における射出成形品の冷却時間を延ばすことによっても「とられ」の問題は低減できるが、やはり同様に完全に解消できるものではなく、また成形サイクルが延びることで生産性を著しく阻害するものであった。
【０００７】
本発明は、上記従来の問題点に鑑みてなされたもので、請求項１、２に係る発明の課題は、従来の成形サイクルを変更することなく、キズや変形などを低減し、量産での品質を安定させることができる円筒成形品の射出成形型を提供することである。
【０００８】
請求項３、４に係る発明の課題は、請求項１、２に係る発明の射出成形型を用いて成形材料を射出成形する円筒成形品の射出成形方法を提供することである。
【０００９】
【課題を解決するための手段】
【００１０】
上記課題を解決するために、請求項１、２に係る発明は、対向する可動側金型および固定側金型のパーティング面を当接させた型閉じ状態において生じる空間部によって円筒成形品を成形する射出成形型において、前記円筒成形品の内周部を成形するように前記可動側金型に取り付けられ、それぞれが組み合わされたときにその外周面が円筒状となる複数のコア部材と、前記円筒成形品の外周部を成形するように前記可動側金型または前記固定側金型の構成要素として用いられるとともに、前記複数のコア部材の外周面と対向する円形孔状の孔成形面を形成したキャビティ部材と、前記可動側金型および前記固定側金型が閉じた状態で形成される前記複数のコア部材の外周面と前記キャビティ部材の孔成形面との間の前記空間部に溶融材料を射出充填した後から、前記パーティング面を離反させる前までである型開き初期動作時に前記可動側金型と前記固定側金型とを締結し、前記パーティング面を離反させたとき以降である型開きの後半動作時に前記可動側金型と前記固定側金型との締結を開放する締結手段と、前記型開き初期動作時に前記複数のコア部材のすべてを前記円筒成形品の内周部より退避位置に移動させるセンタコアと、前記型開き後半動作時に前記円筒成形品の外周部を保持するように前記キャビティ部材と対向して配置されるスライド保持部材に取り付けられたワーク保持手段と、を具備する。
【００１１】
請求項３に係る発明は、対向する可動側金型および固定側金型のパーティング面を当接させた型閉じ状態において生じる空間部によって円筒成形品を成形する射出成形方法において、前記円筒成形品の内周部を成形するように前記可動側金型に取り付けられ、それぞれが組み合わされたときにその外周面が円筒状となる複数のコア部材と、前記円筒成形品の外周部を成形するように前記可動側金型または前記固定側金型の構成要素として用いられるとともに、前記複数のコア部材の外周面と対向する円形孔状の孔成形面を形成したキャビティ部材と、前記円筒成形品の一方の端部側を成形するように前記キャビティ部材に対向して配置されたスライド保持部材と、を、前記可動側金型および前記固定側金型を型閉じ状態にして前記パーティング面を当接させて、前記複数のコア部材の外周面と前記キャビティ部材の孔成形面との間に前記空間部を形成し、その後、前記空間部に溶融材料を射出充填し、しかる後、前記パーティング面の当接を締結したまま前記コア部材の外周面を前記円筒成形品の軸心に向けて移動させて、該円筒成形品の内周部より前記複数のコア部材のすべての外周面を退避させた後、前記可動側金型と前記固定側金型との締結を解除して前記パーティング面を離反させて前記円筒成形品の外周部を前記キャビティ部材の孔成形面から離脱し、前記円筒成形品を前記キャビティ部材を有しない固定側金型または可動側金型に保持したまま型開き動作を完了させ、前記円筒成形品を取り出す。
【００１２】
請求項４に係る発明は、請求項３記載の円筒成形品の射出成形方法において、前記円筒成形品を前記キャビティ部材を有しない固定側金型または可動側金型に保持したまま型開き動作を完了させ、前記円筒成形品を取り出すことに替えて、前記円筒成形品を前記スライド保持部材に取り付いたワーク保持手段に保持したまま型開き動作を完了させ、前記円筒成形品を取り出す。
【００１３】
請求項１、２に係る発明の円筒成形品の射出成形型では、射出成形後の射出成形機による型開き初期動作時では、可動側金型および固定側金型のパーティング面（パーティングライン）が開くことなく、このパーティング面が開くことよりも先に成形品の内周部を成形する複数のコア部材のすべての外周面を、円筒成形品の内周部より離れる向きの半径方向内側へ移動させて退避させることにより、円筒成形品はその軸心方向に成形収縮することが可能となり、成形品外周部のキャビティ部材側への押圧力が減少する。ついで、射出成形機による型開き後半の動作では、円筒成形品の外周部の一端側をスライド保持部材に取り付けられたワーク保持手段により保持して、円筒成形品の外周部の大部分を成形するキャビティ部材の孔成形面より引き出すことにより、キャビティ部材より円筒成形品を容易に離脱できる。
【００１６】
請求項２に係る発明の円筒成形品の射出成形型では、上記作用に加え、ワーク保持手段は、円筒成形品の外周部に凸または凹となる外部アンダーカット部を形成する複数の外スライド部材から構成され、可動側金型が型開きを開始するまで外部アンダーカット部を介して円筒成形品をスライド保持部材に保持させることにより、円筒成形品の外周部に外部アンダーカット部を形成し、かつ、この外部アンダーカット部を利用して確実に円筒成形品をキャビティ部材から離脱させる。
【００１７】
請求項３に係る発明の円筒成形品の射出成形方法では、空間部に溶融材料を射出充填してから、パーティング面の当接を締結したまま、複数のコア部材のすべての外周面を円筒成形品の軸心に向けて移動させて円筒成形品の内周部より複数のコア部材のすべての外周面を退避させ、しかる後、可動側金型と固定側金型との締結を解除して互いのパーティング面を離反させ、円筒成形品の外周部をキャビティ部材の孔成形面から離脱し、円筒成形品をキャビティ部材を有しない固定側金型または可動側金型に保持したまま型開き動作を完了させ、円筒成形品を取り出すことにより、円筒成形品と射出成形型の各部材との離型を円滑にし、円筒成形品を固定側金型または可動側金型に保持して、取り出し易い状態にする。
【００１８】
請求項４に係る発明の円筒成形品の射出成形方法では、空間部に溶融材料を射出充填してから、パーティング面の当接を締結したまま、複数のコア部材のすべての外周面を円筒成形品の軸心に向けて移動させて円筒成形品の内周部より複数のコア部材のすべての外周面を退避させ、しかる後、可動側金型と固定側金型との締結を解除して互いのパーティング面を離反させ、円筒成形品の外周部をキャビティ部材の孔成形面から離脱し、この離脱した円筒成形品をスライド保持部材に取り付いたワーク保持手段に保持したまま型開き動作を完了させ、円筒成形品を取り出すことにより、円筒成形品と射出成形型の各部材との離型を円滑にし、円筒成形品をワーク保持手段に保持して、取り出し易い状態にする。
【００１９】
【発明の実施の形態】
以下、具体的な実施の形態について説明する。なお、本発明の実施の形態における成形材料は、樹脂材料、金属材料等であって、溶融可能で且つ冷却後に固化することによって成形加工が可能な材料に適用できるものである。
【００２０】
（実施の形態１）
図１〜図１１は実施の形態１を示し、図１は円筒成形品の射出成形型の縦断面図、図２は第１スライド部材の斜視図、図３はコア棒の斜視図、図４は円筒成形品の縦断面図、図５はアンギュラカムと外スライド部材との係合を示す縦断面図、図６は型閉じ状態の射出成形型の縦断面図、図７は第１段階の型開き状態の射出成形型の縦断面図、図８は第２段階の型開き状態の射出成形型の縦断面図、図９は第３段階の型開き状態の射出成形型の縦断面図、図１０は最終段階の型開き状態の射出成形型の縦断面図、図１１は円筒成形品の突き出し状態の射出成形型の縦断面図である。
【００２１】
図１において、固定側金型１は、固定側型板４、ランナ落下板６および固定側取り付け板３を有し、固定側取り付け板３に植設されたサポートピン３６ａにランナ落下板６および固定側型板４が摺動自在に嵌装されている。また、ランナ落下板６には、段付き頭部を有するストップピン３０ａ、３０ｂが互いに異なる方向から螺着され、固定側型板４、ランナ落下板６および固定側取り付け板３は、互いに図示しない射出成形機の型開き方向に所定量だけ隔離可能になっている。固定側型板４は、円筒成形品２０の外周部２０ａ（図４参照）を形成するためのキャビティ部材として機能する円形孔状の孔成形面４ａを有するものであり、この固定側型板４には、孔成形面４ａに直交するようにして円筒成形品２０の内周部２０ｂ（図４参照）の一部とともに端面を形成する端部成形面を有する固定側コア部材５がバネ３２を介して成形位置と退避位置とに移動可能に保持されている。このバネ３２は、固定側型板４に設けたザグリ穴内に型開き方向に付勢されて収納されている。
【００２２】
また、固定側型板４に設けたザグリ穴の底面とランナ落下板６との間には、ストップピン３０ｂを貫通するとともに型開き方向に付勢されたバネ３１を挟持する。さらに、固定側取り付け板３には、成形機のノズルから樹脂流路７ａを形成するスプルーブッシュ７がランナ落下板６を貫通して具備され、この樹脂流路７ａと連通するランナ５ａと円筒成形品２０まで連通するピンポイントゲート５ｂとが固定側コア部材５に形成されている。また固定側型板４のザグリ穴に収納されたバネ３２によって持ち上げられる固定側コア部材５の移動量を規制するように、固定側型板４にそのネジ部を螺着するとともに、固定側コア部材５を貫通した状態の軸部とその端に頭部を有するストップピン９が配備されている。また、固定側取り付け板３には、ランナ落下板６を貫通してランナ５ａ内の樹脂を保持可能にするランナロックピン８が植設されている。
【００２３】
一方、可動側金型２は、固定側型板４と対向するストリッパプレート１０と、スライド保持プレート１１と、コア保持プレート１２と、可動側取り付け板１３とから構成され、コア保持プレート１２に植設されたガイドピン３６ｂに、ストリッパプレート１０とスライド保持プレート１１とに加え、固定側金型１の固定側型板４が摺動自在に嵌装されている。コア保持プレート１２と可動側取り付け板１３とは固着され、スライド保持プレート１１は、このスライド保持プレート１１にそのネジ部を螺着するとともに、コア保持プレート１２および可動側取り付け板１３を貫通した状態の軸部とその端に頭部を有する制限ボルト３３によって、射出成形機の型開き方向に所定量だけ隔離可能な状態でコア保持プレート１２と型閉じ時には当接している。また、ストリッパプレート１０は、このストリッパプレート１０にそのネジ部を螺着するとともに、スライド保持プレート１１と、コア保持プレート１２と、可動側取り付け板１３とを貫通した状態の軸部とその端に頭部を有する突き出しロッド３４によって射出成形機の型開き方向に所定量だけ摺動可能な状態でスライド保持プレート１１と型閉じ時には当接している。制限ボルト３３の軸部の長さ、および突き出しロッド３４の軸部の長さは、スライド保持プレート１１とコア保持プレート１２とが分離したときに、あるいはストリッパプレート１０とスライド保持プレート１１とが分離したときに前記所定量だけ隔離するように設定されている。
【００２４】
このストリッパプレート１０の中央には、後述のセンタコアとしてのコア棒１４の周囲に配設される第１スライド部材１５、第２スライド部材１６の各傾斜面１５ｄ（図２参照）、１６ｄと当接する傾斜面を備えた押さえブロック１０ａが一体に取り付けられている。以下の説明では、押さえブロック１０ａを有するストリッパプレート１０の全体をストリッパプレート１０と称する。このストリッパプレート１０は、スライド保持部材として機能する。コア保持プレート１２におけるスライド保持プレート１１側には、段部を有する穴が形成されており、この穴にコア棒１４の基端側（図１では左側）が固定されている。従って、コア保持プレート１２と可動側取り付け板１３は従来技術における基板１５１（図１７参照）に相当する。コア保持プレート１２から突出していて、先端側（図１では右側）の傾斜角度が交互に異なるように形成された錐形の外面を備えたコア棒１４の周囲に円筒成形品２０（図４参照）の内周部２０ｂ（図４参照）を形成する第１スライド部材１５および第２スライド部材１６を交互に配置する。図１および図２では、各３個を配置している。これらはコア部材として機能する。
【００２５】
図２および図３において、コア棒１４の傾斜角度が互いに異なる外面１４ａ、１４ｂ（傾斜角度は第１スライド部材１５と係合する外面１４ａが外面１４ｂよりも大きい）は、外面１４ａ、１４ｂとその底面が平行に形成された蟻溝１４ｃが軸心方向（コア棒１４の中心軸線に対して傾斜角度分だけ傾いて上下方向に形成されるが、便宜上このように呼ぶ）に延びるとともに、この蟻溝１４ｃに係合させて第１スライド部材１５のアリ１５ｃ、第２スライド部材１６のアリ１６ｃをそれぞれ摺動自在に具備している。また、第１スライド部材１５と第２スライド部材１６とは、第１スライド部材１５および第２スライド部材１６の基端側（大径側）で外向きに形成された円周突出部１５ａ、１６ａ（図１参照）を放射方向に摺動自在に、かつ、スライド保持プレート１１を貫通した状態でスライド保持プレート１１に保持されている。なお、ネジ転写部１５ｂは、円筒成形品２０にアンダーカットとなる内周部２０ｂ（例えばヘリコイドネジ）を形成する部位である。ネジ転写部１６ｂ（図１参照）も同様である。
【００２６】
また、ストリッパプレート１０の固定側型板４との対向面には、円筒成形品２０の外周アンダーカット部２０ｃ（図４参照）を形成するための外スライド部材１７を当接させるとともに、この外スライド部材１７を半径方向（即ち、コア棒１４の軸心に対して放射方向）に摺動自在に具備している。この外スライド部材１７は、スライド保持部材（ストリッパプレート１０に相当）に取り付けられるワーク保持手段として機能し、内側に円筒成形品２０の外周アンダーカット部２０ｃを形成すると共に、型開き時にこれを保持するフック状段部１７ｂを有する。この外スライド部材１７は円筒成形品２０の外周アンダーカット部２０ｃを形成するため、周方向に６等分して配置されている。なお、図１では、外スライド部材１７の上側の一部を破断線で表示して、図示を省略している。ＰＬはパーティングラインの略で固定側型板４とストリッパプレート１０との当接面を示す。従って、可動側金型２と固定側金型１との各板が当接するパーティング面ということができる。以下ＰＬと略す。
【００２７】
また、図５に示すように、アンギュラカム２１はテーパ部２１ｂとストレート部２１ａとを有し、その断面は略長方形（図５のＡ矢視図参照）をなしている。型締め初期動作時に、外スライド部材１７のテーパ孔１７ａ（具体的には、テーパ孔１７ａのテーパ面と対向する面部）にテーパ部２１ｂ（具体的には、テーパ部２１ｂの前記テーパ孔１７ａのテーパ面とは反対側の面部）がテーパ嵌合することにより、外スライド部材１７を円周内側方向に移動せしめ、型締め後半動作ではストレート部２１ａによって外スライド部材１７は停止する。図１に示すように、アンギュラカム２１は、ストレート部２１ａの基端側が固定側型板４に植設されている。このアギュラカム２１は、外スライド部材１７と同じくコア棒１４の周囲の６ヶ所に配置されている。このアンギュラカム２１のテーパ部２１ｂを型締め時に収納するように、ストリッパプレート１０には、孔が６ヶ所形成されている。
【００２８】
図１において、マグネット１８、１８はストリッパプレート１０および固定側型板４の外周面にそれぞれ取り付けられて、互いに吸着維持可能となっており、所望する力にてストリッパプレート１０と固定側型板４とを締結することができ、締結手段として機能している。引張りリンク３５はスライド保持プレート１１と固定側型板４とを所定量だけ型開き可能に連結固定する部材であって、スライド保持プレート１１および固定側型板４の各側面に植設したボルト（ボルトの頭部だけが見えている）によって支持されている。
【００２９】
つぎに、上記構成の射出成形型を用いた円筒成形品の射出成形方法を図６〜図１１を用いて説明する。図６〜図１１は、射出成形機に取り付けた射出成形型の成形ステップを順番に図示しており、射出成形機は図示を省略している。また、図７〜図１１では、固定側コア部材５に形成されたランナ５ａは図示を省略している。図６は型閉じ状態であり、樹脂流路７ａ、ランナ５ａ、ピンポイントゲート５ｂを介して、固定側型板４、第１スライド部材１５、第２スライド部材１６、固定側コア部材５のそれぞれで形成される空間部（キャビティ）内で射出成形された溶融材料としての樹脂材料により、円筒成形品２０を成形した状態にある。適正な樹脂冷却が完了後、図７に示すように、射出成形機の型開き動作によってピンゲート５ｂがゲートカットされ、固定側型板４とランナ落下板６とが隔離する。また、同時に固定側コア部材５は、バネ３２の付勢によって固定側取り付け板３側へ移動するので、図４に示す成形品２０の内周部２０ｂより固定側コア部材５の端部成形面は退避する。このとき、固定側コア部材５の移動量は、固定側型板４に螺着したストップピン９により規制されている。
【００３０】
つぎに、図８に示すように、射出成形機の型開き動作が継続し、ＰＬは閉じたままでスライド保持プレート１１に対して、コア保持プレート１２と可動側取り付け板１３とは一体的に型開き方向に離脱する。このとき、コア保持プレート１２に取り付けられたコア棒１４は、第１スライド部材１５、第２スライド部材１６に対して相対的に離脱（移動）すると同時に、第１スライド部材１５の円周突出部１５ａ、第２スライド部材１６の円周突出部１６ａが、スライド保持プレート１１によって案内されるので、第１スライド部材１５、第２スライド部材１６は半径中心方向（コア棒１４の軸心に向かう方向）に移動する。従って、円筒成形品２０の内周部２０ｂより、第１スライド部材１５、第２スライド部材１６のアンダーカットとなるヘリコイドネジを形成するネジ転写部１５ｂ、１６ｂ（図１参照）は離脱する。図６〜図８までの型開き動作は、型開き初期動作に対応する。
【００３１】
さらに、射出成形機の型開き動作が進行し、図９に示すように、マグネット１８の吸着が離れＰＬが開く。このとき、固定側型板１４に植設したアンギュラカム２１のテーパ部２１ｂが外スライド部材１７のテーパ孔１７ａと当接するまで外スライド部材１７は移動することがないので、円筒成形品２０の外周アンダーカット部２０ｃによって円筒成形品２０は可動側金型２に保持され、固定側型板４の孔成形面４ａから離脱する。
【００３２】
さらに、射出成形機の型開き動作が進行すると、図１０で示すように、引張りリンク３５によって可動側金型２と固定側金型１との移動が制限され、この際にアンギュラカム２１のテーパ部２１ｂが外スライド部材１７のテーパ孔１７ａを押圧するので、外スライド部材１７は円筒成形品２０の外周アンダーカット部２０ｃの固定保持状態を解除するようになり、そしてランナ落下板６が固定側取り付け板３よりストップピン３０ａでの規制量分だけ開き、ランナ５ａよりランナロックピン８が抜ける。この状態で型開き動作は完了である。図９、図１０までの型開き動作は型開き後半動作に対応する。
【００３３】
図１１はさらに円筒成形品２０を取り出すための突き出し状態を示しており、本例では、突き出しロッド３４を射出成形機の突き出し機構（図示省略）によって押し出すことで、固定側型板４に向かってストリッパプレート１０を移動させている。このストリッパプレート１０の移動により、スライド保持プレート１１とストリッパプレート１０との間隔が広がり、スライド保持プレート１１に保持されている第１スライド部材１５、第２スライド部材１６に対して、円筒成形品２０がストリッパプレート１０の移動方向に移動することになる。この円筒成形品２０の移動により、円筒成形品２０の内側に入り込んだ状態となっている第１スライド部材１５、第２スライド部材１６の先端部側の長さが少なくなるので、円筒成形品をストリッパプレート１０から容易に取り出せるようになる。勿論、図１０までの状態でも、円筒成形品２０を取り出せるのであれば、本動作は不要である。以上の動作によって、円筒成形品に、変形、キズを発生させることなく、成形することができる。
【００３４】
本実施の形態によれば、従来の成形サイクルを変更することなく、型開き時の各型構成要素の順序立った動きにより、成形されたアンダーカット部を内外周部に有する円筒成形品にキズや変形を与えることなく、射出成形型内から取り出すことができ、量産での品質を安定させることができる。
【００３５】
（実施の形態２）
図１２〜図１５は実施の形態２を示し、図１２は円筒成形品の射出成形型の縦断面図、図１３は型閉じ状態の射出成形型の縦断面図、図１４は第１段階の型開き状態の射出成形型の縦断面図、図１５は第２段階の型開き状態の射出成形型の縦断面図である。本実施の形態は、実施の形態１と成形された円筒成形品が固定側金型に残る点が異なり、他の部分は実施の形態１と同一のため、異なる部分のみ説明し、同一の部材には同一の符号を付し説明を省略する。
【００３６】
図１２に示す本実施の形態の射出成形型では、図４に図示した円筒成形品２０において、外周部に形成される外周アンダーカット部２０ｃの成形を、固定側型板４に取り付けられる外スライド部材１７によって成形するようにしている。従って、実施の形態１に対して、円筒成形品２０の外周部に形成される外周アンダーカット部２０ｃを成形する外スライド部材１７の配置位置が、固定側金型１側になっている。また、成形品２０の外周部２０ａを成形する部分は可動側金型２におけるストリッパプレート１０になっており、図１における固定側コア部材５を用いていない。
【００３７】
図１２において、実施の形態１と同様に、固定側金型１は、固定側型板４とランナ落下板６と固定側取り付け板３とを有し、固定側取り付け板３に植設されたサポートピン３６ａにランナ落下板６および固定側型板４が摺動自在に嵌装されている。また、ランナ落下板６には、段付き頭部を有するストップピン３０ａ、３０ｂが互いに異なる方向から螺着され、固定側型板４、ランナ落下板６および固定側取り付け３は、互いに図示しない射出成形機の型開き方向に所定量だけ隔離可能になっている。スライド保持部材として機能する固定側型板４は、円筒成形品２０の外周アンダーカット部２０ｃを形成する外スライド部材１７（ワーク保持手段として機能する）を半径方向に摺動自在に具備している。ＰＬはパーティングラインの略で、固定側型板４とストリッパープレート１０との当接面を示す。従って、可動側金型２と固定側金型１との各板が当接するパーティング面ということができる。以下、ＰＬと略称する。
【００３８】
可動側金型２のストリッパプレート１０には、アンギュラカム２１が配設され、図５に示すように、アンギュラカム２１はストレート部２１ａとテーパ部２１ｂとを有し、ストレート部２１ａ側をストリッパプレート１０に植設している。アンギュラカム２１のテーパ部２１ｂは、外スライド部材１７のテーパ孔１７ａと対応する位置に形成された固定側型板４の孔およびランナ落下板６の孔のそれぞれに入るようになっている。型締め初期動作時では、外スライド部材１７のテーパ孔１７ａ（具体的には、テーパ孔１７ａのテーパ面と対向する面部）にテーパ部２１ｂ（具体的には、テーパ孔１７ａのテーパ面とは反対側のテーパ部２１ｂの面部）がテーパ嵌合することにより、外スライド部材１７を円周内側方向に移動せしめ、型締め後半動作では、ストレート部２１ａ（図５参照）によってスライド部材１７は停止する。また、ストリッパプレート１０は、円筒成形品２０の外周部２０ａを形成するための、即ち、円筒成形品２０の外周アンダーカット部２０ｃがない外周面を形成するための円形孔状の孔成形面１０ｂを有しており、キャビティ部材として機能する。また、固定側金型１の固定側型板４（スライド保持部材）の側面と可動側金型２のストリッパプレート１０の側面とには、締結手段としての磁石１８、１８がそれぞれ取り付けられている。その他の射出成形型の構成は実施の形態１と同様である。
【００３９】
つぎに、上記構成の射出成形型を用いた円筒成形品の射出成形方法を図１３〜図１５を用いて説明する。図１３〜図１５は、射出成形機に取り付けた射出成形型の成形ステップを順番に図示しており、射出成形機の図示は省略されている。図１３は型閉じ状態であり、実施の形態１と同様に、円筒成形品２０を成形した状態である。適正な樹脂冷却が完了後、図１４に示すように、射出成形機の型開き動作によって、ピンポイントゲート５ｂがゲートカットされ、固定側型板４とランナ落下板６が隔離する。さらに射出成形機の型開き動作が継続し、ＰＬは閉じたままコア保持プレート１２と可動側取り付け板１３は一体的に型開き方向に、スライド保持プレート１１に対して離脱する。以後、センタコアとしてのコア棒１４が型開き方向に後退することにより、第１スライド部材１５、第２スライド部材１６の円周突出部１５ａ、１６ａによって、第１スライド部材１５、第２スライド部材１６がコア棒１４の軸心に向かって移動し、円筒成形品２０の内周部２０ｂより第１スライド部材１５、第２スライド部材１６のネジ転写部１５ｂ、１６ｂ（図１２参照）が離脱する。図１３および図１４の型開き動作は、型開き初期動作に対応する。
【００４０】
さらに、射出成形機の型開き動作が進行すると、可動側金型２と固定側金型１とのパーティング面（ＰＬ面）が開き、図１５になる前に、まずストリッパプレート１０と固定側型板４が隔離し、この隔離の際の初期時にはアンギュラカム２１のストレート部２１ａ（図５参照）に沿って外スライド部材１７のテーパ孔１７ａのストレート部が相対的に動くことになり、よって、外スライド部材１７は動くことがないので、円筒成形品２０の外周アンダーカット部２０ｃが外スライド部材１７の内側に形成されたフック状段部１７ｂ（図５参照）によって保持されることによって円筒成形品２０は固定側型板４に保持された状態となり、この状態で円筒成形品２０の外周部２０ａはストリッパプレート１０の円形孔状の孔成形面１０ｂ（図１２参照）から密着状態が解除されて移動する。この状態から型開きが進行すると、図１５に示すように、アンギュラカム２１のテーパ部２１ｂによって外スライド部材１７のテーパ孔１７ａが押され、外スライド部材１７は半径方向の外向きに移動して円筒成形品２０から離脱する。
【００４１】
さらに、成形機の型開き動作が進行すると、図１５に示すように、固定側型板４に形成したランナ５ａよりランナロックピン８が抜ける。この状態で型開き動作は完了する。図１５までの型開き動作は、型開き後半動作に対応する。
【００４２】
本実施の形態によれば、実施の形態１と同様の効果に加え、円筒成形品が可動側金型に残るのではなく、固定側金型に保持されるため、可動側金型に配備されていた円筒成形品の突き出し機構（実施の形態１の図１における突き出しロッド３４および射出成形機に備えられた突き出し手段等）を使う必要がなく、型構造を簡素化することができる。
【００４３】
【発明の効果】
請求項１、２に係る発明によれば、円筒成形品は軸心方向に成形収縮することが可能となり、成形品外周部のキャビティ部材側への押圧力が減少し、円筒成形品の外周部の一端側をスライド保持部材に取り付けられたワーク保持手段により保持して、成形品の外周部の大部分を成形するキャビティ部材の孔成形面より引き出すことにより、キャビティ部材より円筒成形品を容易に離脱できるので、従来の成形サイクルを変更することなく、円筒成形品のキズや変形などを低減し、量産での品質を安定させることができる。
【００４６】
請求項２に係る発明によれば、上記効果に加え、円筒成形品の外周部にアンダーカット部を形成し、かつ、このアンダーカット部を利用して確実に円筒成形品をキャビティ部材から離脱させるようにしたので、円筒成形品とキャビティ部材とのとられによる変形、キズを確実に防ぐことができる。
【００４７】
請求項３に係る発明によれば、円筒成形品と射出成形型の各部材との離型を円滑にし、円筒成形品を固定側金型または可動側金型に保持して、取り出し易い状態にしたので、成形された円筒成形品の変形やキズを確実に防ぎ、量産での品質を安定させることができる。
【００４８】
請求項４に係る発明によれば、円筒成形品と射出成形型の各部材との離型を円滑にし、円筒成形品をワーク保持手段に保持して取り出し易い状態にしたので、成形された円筒成形品の変形やキズを確実に防ぎ、量産での品質を安定させることができるとともに、円筒成形品のハンドリングを容易に行うことができる。
【図面の簡単な説明】
【図１】実施の形態１の円筒成形品の射出成形型の縦断面図である。
【図２】実施の形態１の第１スライド部材の斜視図である。
【図３】実施の形態１のコア棒の斜視図である。
【図４】実施の形態１の円筒成形品の縦断面図である。
【図５】実施の形態１のアンギュラカムと外スライド部材との係合を示す縦断面図である。
【図６】実施の形態１の型閉じ状態の射出成形型の縦断面図である。
【図７】実施の形態１の第１段階の型開き状態の射出成形型の縦断面図である。
【図８】実施の形態１の第２段階の型開き状態の射出成形型の縦断面図である。
【図９】実施の形態１の第３段階の型開き状態の射出成形型の縦断面図である。
【図１０】実施の形態１の最終段階の型開き状態の射出成形型の縦断面図である。
【図１１】実施の形態１の円筒成形品の突き出し状態の射出成形型の縦断面図である。
【図１２】実施の形態２の円筒成形品の射出成形型の縦断面図である。
【図１３】実施の形態２の型閉じ状態の射出成形型の縦断面図である。
【図１４】実施の形態２の第１段階の型開き状態の射出成形型の縦断面図である。
【図１５】実施の形態２の第２段階の型開き状態の射出成形型の縦断面図である。
【図１６】従来技術の成形型に取り付けた射出成形状態におけるコアを図１７のｙ方向から見た平面図である。
【図１７】従来技術の図１６のｗ−ｗ線に沿った軸線を通る断面図である。
【図１８】従来技術の開きコアを取り付けた成形型の構成要素の型開き第１段階における位置を示す図である。
【図１９】従来技術の開きコアを取り付けた成形型の構成要素の型開き第２段階における位置を示す図である。
【図２０】従来技術の開きコアを取り付けた成形型の構成要素の型開き第３段階における位置を示す図である。
【符号の説明】
１固定側金型
２可動側金型
４固定側型板
１０ストリッパプレート
１４コア棒
１５第１スライド部材
１６第２スライド部材
１７外スライド部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an injection mold and an injection molding method for accurately molding a cylindrical molded product.
[0002]
[Prior art]
For example, as an injection mold for a cylindrical molded product, an injection mold for molding a molded product having an undercut such as a helicoid screw on its inner peripheral surface is disclosed in Japanese Patent Publication No. 59-14333. This prior art will be described with reference to FIGS. 16 and 17, the first slide member 102 and the second slide member 103 are alternately and axially disposed around the core rod 101 having a conical outer surface whose upper side inclination angles are alternately different. The slide member is arranged to be slidable in the direction, and a desired helicoid-shaped undercut shape is engraved on the outer peripheral side of the upper end of these slide members.
[0003]
Next, an operation at the time of injection molding of an injection mold having the core rod having the above-described configuration will be described. At the time of the injection molding operation, as shown in FIG. 18, the mold 107 is closed and the movable mold 105 and the fixed mold 106 are closed together, and the nozzle is placed in the space (cavity) between them. A molding material is injected through 109 to form an injection molded article 108. After the mold 107 is opened after molding, that is, after the movable mold 105 and the fixed mold 106 are separated from each other and the outer peripheral surface of the injection molded product 108 is exposed, as shown in FIG. When the plates 152, 153, and 154 are moved in the mold opening direction with respect to the substrate 151 by the stroke S, the core rod 101 is fixed to the substrate 151. 2 The slide member 103 and the first slide member 102 move, that is, the first slide member 102 and the second slide member 103 slide relative to the core rod 101 in the mold opening direction, and the axis of the core rod 101 Move towards. As a result, the undercut shapes of the first slide member 102 and the second slide member 103 move away from the inner peripheral portion of the injection molded product 108 in the radial center direction, and as shown in FIG. When the plate 154 is raised, the injection molded product 108 can be taken out.
[0004]
This makes it possible to freely add undercuts such as complex helicoid screws and cam grooves to the inner periphery, eliminating the need for secondary processing for creating undercuts on injection-molded products, and making it cheap and stable. Production is possible.
[0005]
[Problems to be solved by the invention]
However, the above prior art has the following problems. That is, in the above prior art, after molding an injection molded product in which an undercut is formed in the inner peripheral portion by the slide members 102 and 103 arranged around the core rod 101, the movable side mold and the fixed side mold Are separated along the parting line, the mold is opened, and then the slide members 102 and 103 are moved. At this time, in the case of injection molding using a resin material, a sufficient pressure is applied to the injection molded product during injection filling, and the resin is cooled while maintaining the pressure. The injection molded product tries to shrink the volume by cooling, but the core member such as the core rod, the first slide member, and the second slide member is present in the center, so it cannot shrink, and the outer periphery of the injection molded product is fixed. In this state, the inner peripheral surface of the side mold is strongly pressed (that is, a state in which internal distortion has occurred in the injection molded product). Therefore, when the mold is opened as it is, the inner peripheral surface of the mold that forms the outer peripheral portion of the injection molded product causes so-called "scratching" such as scratches and deformation on the outer peripheral portion of the injection molded product, There was a problem that appearance quality was impaired.
[0006]
In addition, if the pressure setting on the injection molding machine applied to the molded product is reduced in order not to cause such “taken off”, the problem of “taken off” is reduced but not completely eliminated. If the pressure setting on the molding machine side is too small, “sinking” will occur in the injection molded product, or anisotropy of the molding shrinkage rate will occur, deteriorating the shape accuracy such as roundness and cylindricity. Therefore, it was also a cause of quality variation in mass production. In addition, the problem of “taken off” can be reduced by extending the cooling time of the injection molded product in the mold, but it cannot be completely eliminated as well, and the productivity is significantly increased by extending the molding cycle. It was an obstacle.
[0007]
The present invention has been made in view of the above conventional problems, Claims 1 and 2 An object of the present invention is to provide an injection mold of a cylindrical molded product that can reduce scratches and deformation and stabilize the quality in mass production without changing the conventional molding cycle.
[0008]
Claims 3 and 4 The subject of the invention according to Claims 1 and 2 Another object of the present invention is to provide an injection molding method for a cylindrical molded article in which a molding material is injection molded using the injection mold of the invention.
[0009]
[Means for Solving the Problems]
[0010]
To solve the above problem, Claims 1 and 2 The invention relates to an injection mold for molding a cylindrical molded product by a space portion generated in a mold closed state where the parting surfaces of the opposed movable mold and fixed mold are brought into contact with each other. It is attached to the movable mold so as to mold the part, and when they are combined, the outer peripheral surface becomes cylindrical. plural The core member is used as a component of the movable mold or the fixed mold so as to mold the outer periphery of the cylindrical molded product, and plural Cavity member formed with a circular hole-shaped hole forming surface facing the outer peripheral surface of the core member, and the movable side mold and the fixed side mold are closed. Be done Above plural The outer peripheral surface of the core member and the hole forming surface of the cavity member Among Injection filling of molten material into the space did rear And before separating the parting surface. At the time of mold opening initial operation, the movable side mold and the fixed side mold are fastened, After the parting surface is separated. Fastening means for releasing the fastening between the movable mold and the fixed mold during the latter half of the mold opening; Said At the time of mold opening initial operation plural Core member All of A center core that moves the inner peripheral portion of the cylindrical molded product to a retracted position, and a slide holding member that is disposed to face the cavity member so as to hold the outer peripheral portion of the cylindrical molded product during the second half of the mold opening operation. Attached work holding means.
[0011]
Claim 3 The present invention relates to an injection molding method in which a cylindrical molded product is molded by a space generated in a mold closed state in which the facing movable mold and the parting surfaces of the fixed mold are in contact with each other. Attached to the movable mold so as to mold the part, When each is combined Cylindrical outer peripheral surface Multiple The core member is used as a component of the movable mold or the fixed mold so as to mold the outer periphery of the cylindrical molded product, and plural A circle facing the outer peripheral surface of the core member Hole A cavity member formed with a hole-forming surface having a shape, and a slide holding member disposed opposite to the cavity member so as to mold one end side of the cylindrical molded product, and the movable side mold and Fixed mold The With the mold closed, the parting surface is brought into contact, plural An outer peripheral surface of the core member and a hole forming surface of the cavity member; Between Forming the space, Then said The space portion is injected and filled with a molten material, and then the outer peripheral surface of the core member is moved toward the axis of the cylindrical molded product while the abutment of the parting surface is fastened. From the inner circumference The plurality Core member All of After the outer peripheral surface of the cylindrical member is retracted, the fastening between the movable side die and the fixed side die is released to separate the parting surface, and the outer peripheral portion of the cylindrical molded product is moved to the hole forming surface of the cavity member. The mold opening operation is completed while the cylindrical molded product is held in the fixed mold or the movable mold without the cavity member, and the cylindrical molded product is taken out.
[0012]
Claim 4 The invention concerned Claim 3 In the method of injection molding of a cylindrical molded article, the mold opening operation is completed while the cylindrical molded article is held in a fixed mold or a movable mold without the cavity member, and the cylindrical molded article is taken out. Then, the mold opening operation is completed while the cylindrical molded product is held by the work holding means attached to the slide holding member, and the cylindrical molded product is taken out.
[0013]
Claims 1 and 2 In the injection molding die of the cylindrical molded product of the invention, in the initial opening operation by the injection molding machine after injection molding, the parting surface (parting line) of the movable side mold and the fixed side mold does not open, Mold the inner periphery of the molded product before the parting surface opens plural Core member All of By moving the outer peripheral surface of the outer peripheral surface radially inward in a direction away from the inner peripheral portion of the cylindrical molded product, the cylindrical molded product can be molded and contracted in the axial direction, and the outer peripheral portion of the molded product The pressing force toward the cavity member side is reduced. Next, in the second half of the mold opening operation by the injection molding machine, one end side of the outer peripheral portion of the cylindrical molded product is held by the work holding means attached to the slide holding member, and most of the outer peripheral portion of the cylindrical molded product is molded. By pulling out from the hole forming surface of the cavity member, the cylindrical molded product can be easily detached from the cavity member.
[0016]
Claim 2 In the injection molding die of the cylindrical molded product according to the invention, in addition to the above-described action, the work holding means is composed of a plurality of outer slide members that form external undercut portions that are convex or concave on the outer peripheral portion of the cylindrical molded product, By holding the cylindrical molded product on the slide holding member via the external undercut portion until the movable mold starts to open, an external undercut portion is formed on the outer peripheral portion of the cylindrical molded product, and this external The cylindrical molded product is reliably detached from the cavity member using the undercut portion.
[0017]
Claim 3 In the injection molding method of the cylindrical molded product according to the invention, after injecting and filling the molten material into the space, the contact of the parting surface is fastened, plural Core member All of From the inner periphery of the cylindrical molded product, move the outer peripheral surface of the plural Core member All of Evacuate the outer peripheral surface of the mold, and then release the fastening between the movable mold and the fixed mold to separate the parting surfaces from each other, and the outer peripheral portion of the cylindrical molded product is detached from the hole forming surface of the cavity member. Then, the mold opening operation is completed while the cylindrical molded product is held in the fixed side mold or the movable side mold not having the cavity member, and the cylindrical molded product is taken out. The mold release is made smooth, and the cylindrical molded product is held in the fixed side mold or the movable side mold to make it easy to take out.
[0018]
Claim 4 In the injection molding method of the cylindrical molded product according to the invention, after injecting and filling the molten material into the space, the contact of the parting surface is fastened, plural Core member All of From the inner periphery of the cylindrical molded product, move the outer peripheral surface of the plural Core member All of Evacuate the outer peripheral surface of the mold, and then release the fastening between the movable mold and the fixed mold to separate the parting surfaces from each other, and the outer peripheral portion of the cylindrical molded product is detached from the hole forming surface of the cavity member. Then, the mold opening operation is completed while the detached cylindrical molded product is held by the work holding means attached to the slide holding member, and the cylindrical molded product is taken out to separate the cylindrical molded product from each member of the injection mold. The mold is made smooth and the cylindrical molded product is held by the work holding means so that it can be easily taken out.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments will be described. The molding material in the embodiment of the present invention is a resin material, a metal material or the like, and can be applied to a material that can be melted and can be molded by solidification after cooling.
[0020]
(Embodiment 1)
1 to 11 show Embodiment 1, FIG. 1 is a longitudinal sectional view of an injection mold of a cylindrical molded product, FIG. 2 is a perspective view of a first slide member, FIG. 3 is a perspective view of a core rod, and FIG. Is a longitudinal sectional view of the cylindrical molded product, FIG. 5 is a longitudinal sectional view showing the engagement between the angular cam and the outer slide member, FIG. 6 is a longitudinal sectional view of the injection mold in the mold closed state, and FIG. FIG. 8 is a longitudinal sectional view of an injection molding die in a second stage mold opening state, FIG. 9 is a longitudinal sectional view of an injection molding mold in a third stage mold opening state, FIG. 10 is a vertical cross-sectional view of the injection mold in the final stage of the mold opening state, and FIG. 11 is a vertical cross-sectional view of the injection mold in the protruding state of the cylindrical molded product.
[0021]
In FIG. 1, the fixed-side mold 1 includes a fixed-side mold plate 4, a runner dropping plate 6, and a fixed-side mounting plate 3, and the runner dropping plate 6 and the support pin 36 a planted on the fixed-side mounting plate 3. The fixed side template 4 is slidably fitted. Further, stop pins 30a and 30b having stepped heads are screwed onto the runner drop plate 6 from different directions, and the fixed side mold plate 4, the runner drop plate 6 and the fixed side mounting plate 3 are not shown in the drawing. A predetermined amount can be isolated in the mold opening direction of the injection molding machine. The fixed-side mold plate 4 has a circular hole-shaped hole forming surface 4 a that functions as a cavity member for forming the outer peripheral portion 20 a (see FIG. 4) of the cylindrical molded product 20. The fixed core member 5 having an end molding surface that forms an end surface together with a part of the inner peripheral portion 20b (see FIG. 4) of the cylindrical molded product 20 so as to be orthogonal to the hole molding surface 4a. Via the molding position and the retracted position. The spring 32 is housed in a counterbore hole provided in the fixed-side template 4 while being biased in the mold opening direction.
[0022]
Further, a spring 31 that passes through the stop pin 30b and is biased in the mold opening direction is sandwiched between the bottom surface of the counterbore hole provided in the fixed side mold plate 4 and the runner dropping plate 6. Further, a sprue bush 7 that forms a resin flow path 7a from the nozzle of the molding machine is provided on the fixed side mounting plate 3 through the runner drop plate 6, and a runner 5a that communicates with the resin flow path 7a and a cylindrical molding are provided. A pinpoint gate 5 b communicating with the product 20 is formed on the fixed core member 5. In addition, the fixed-side mold plate 4 is screwed to the fixed-side mold plate 4 so that the movement amount of the fixed-side core member 5 lifted by the spring 32 housed in the counterbore hole of the fixed-side mold plate 4 is regulated. A shaft portion in a state of penetrating the member 5 and a stop pin 9 having a head at its end are provided. In addition, a runner lock pin 8 is provided in the fixed side mounting plate 3 so as to penetrate the runner dropping plate 6 and hold the resin in the runner 5a.
[0023]
On the other hand, the movable mold 2 is composed of a stripper plate 10 facing the fixed mold 4, a slide holding plate 11, a core holding plate 12, and a movable mounting plate 13. In addition to the stripper plate 10 and the slide holding plate 11, the fixed side mold plate 4 of the fixed side mold 1 is slidably fitted to the guide pin 36b provided. The core holding plate 12 and the movable side mounting plate 13 are fixed, and the slide holding plate 11 is screwed into the slide holding plate 11 and threaded through the core holding plate 12 and the movable side mounting plate 13. The shaft holding portion and the limiting bolt 33 having a head at its end are in contact with the core holding plate 12 at the time of mold closing in a state where it can be separated by a predetermined amount in the mold opening direction of the injection molding machine. Further, the stripper plate 10 has a threaded portion screwed into the stripper plate 10, and a shaft portion in a state of passing through the slide holding plate 11, the core holding plate 12, and the movable side mounting plate 13, and an end thereof. The projecting rod 34 having a head is in contact with the slide holding plate 11 at the time of mold closing while being slidable by a predetermined amount in the mold opening direction of the injection molding machine. The length of the shaft portion of the limiting bolt 33 and the length of the shaft portion of the protruding rod 34 are determined when the slide holding plate 11 and the core holding plate 12 are separated or when the stripper plate 10 and the slide holding plate 11 are separated. Is set to isolate the predetermined amount.
[0024]
At the center of the stripper plate 10, the first slide member 15 and the inclined surfaces 15d (see FIG. 2) 16d of the first slide member 15 and the second slide member 16 disposed around a core rod 14 serving as a center core, which will be described later, come into contact. A holding block 10a having an inclined surface is integrally attached. In the following description, the entire stripper plate 10 having the holding block 10a is referred to as a stripper plate 10. The stripper plate 10 functions as a slide holding member. A hole having a step portion is formed on the slide holding plate 11 side of the core holding plate 12, and the base end side (left side in FIG. 1) of the core rod 14 is fixed to this hole. Therefore, the core holding plate 12 and the movable attachment plate 13 correspond to the substrate 151 (see FIG. 17) in the prior art. A cylindrical molded product 20 (see FIG. 4) is provided around the core rod 14 that protrudes from the core holding plate 12 and has a conical outer surface formed so that the inclination angles on the tip side (right side in FIG. 1) are alternately different. The first slide member 15 and the second slide member 16 forming the inner peripheral portion 20b (see FIG. 4) are alternately arranged. In FIG. 1 and FIG. 2, three each are arranged. These function as core members.
[0025]
2 and 3, the outer surfaces 14a and 14b having different inclination angles of the core rod 14 (the outer surface 14a engaging with the first slide member 15 is larger than the outer surface 14b) are the outer surfaces 14a and 14b and the outer surfaces 14a and 14b. A dovetail groove 14c having a bottom surface formed in parallel extends in the axial direction (inclined by an inclination angle with respect to the central axis of the core rod 14 and is formed in the vertical direction, but is referred to as such for convenience). The dovetail 15c of the first slide member 15 and the dovetail 16c of the second slide member 16 are slidably engaged with the groove 14c. Moreover, the 1st slide member 15 and the 2nd slide member 16 are the circumferential protrusion parts 15a and 16a formed outward on the base end side (large diameter side) of the 1st slide member 15 and the 2nd slide member 16. (Refer to FIG. 1) is slidable in the radial direction and is held by the slide holding plate 11 in a state of passing through the slide holding plate 11. The screw transfer portion 15b is a portion where an inner peripheral portion 20b (for example, a helicoid screw) that is an undercut is formed in the cylindrical molded product 20. The same applies to the screw transfer portion 16b (see FIG. 1).
[0026]
Further, an outer slide member 17 for forming an outer peripheral undercut portion 20c (see FIG. 4) of the cylindrical molded product 20 is brought into contact with the surface of the stripper plate 10 facing the fixed side mold plate 4, and the outer The slide member 17 is provided so as to be slidable in the radial direction (that is, in the radial direction with respect to the axis of the core rod 14). This outer slide member 17 functions as a work holding means attached to a slide holding member (corresponding to the stripper plate 10), and forms an outer peripheral undercut portion 20c of the cylindrical molded product 20 on the inner side and holds this when the mold is opened. And a hook-shaped step portion 17b. The outer slide member 17 is divided into six equal parts in the circumferential direction so as to form the outer peripheral undercut portion 20 c of the cylindrical molded product 20. In FIG. 1, a part of the upper side of the outer slide member 17 is indicated by a broken line, and the illustration is omitted. PL is an abbreviation for a parting line, and indicates a contact surface between the fixed-side template 4 and the stripper plate 10. Therefore, it can be said that it is a parting surface on which the plates of the movable mold 2 and the fixed mold 1 abut. Hereinafter abbreviated as PL.
[0027]
Further, as shown in FIG. 5, the angular cam 21 has a tapered portion 21b and a straight portion 21a, and the cross section thereof is substantially rectangular (see the view in the direction of arrow A in FIG. 5). During the initial clamping operation, the tapered portion 17b (specifically, the tapered hole 17a of the tapered portion 21b) is formed in the tapered hole 17a of the outer slide member 17 (specifically, the surface portion facing the tapered surface of the tapered hole 17a). The outer slide member 17 is moved in the inner circumferential direction by the taper fitting of the surface portion opposite to the tapered surface), and the outer slide member 17 is stopped by the straight portion 21a in the latter half of the mold clamping operation. As shown in FIG. 1, the angular cam 21 has a base end side of the straight portion 21 a implanted in the fixed-side template 4. The angular cams 21 are arranged at six locations around the core rod 14 as with the outer slide member 17. Six holes are formed in the stripper plate 10 so that the tapered portion 21b of the angular cam 21 is accommodated when the mold is clamped.
[0028]
In FIG. 1, magnets 18 and 18 are attached to the outer peripheral surfaces of the stripper plate 10 and the fixed-side mold plate 4, respectively, and can be attracted and maintained with each other. And can function as a fastening means. The tension link 35 is a member that connects and fixes the slide holding plate 11 and the fixed side mold plate 4 so as to be openable by a predetermined amount, and is bolted on each side of the slide holding plate 11 and the fixed side mold plate 4 ( Only the head of the bolt is visible).
[0029]
Next, an injection molding method of a cylindrical molded product using the injection mold having the above-described configuration will be described with reference to FIGS. 6 to 11 sequentially illustrate the molding steps of the injection mold attached to the injection molding machine, and the illustration of the injection molding machine is omitted. 7 to 11, the runner 5a formed on the fixed core member 5 is not shown. FIG. 6 shows the mold closed state, and each of the fixed-side mold plate 4, the first slide member 15, the second slide member 16, and the fixed-side core member 5 through the resin flow path 7a, the runner 5a, and the pinpoint gate 5b. The cylindrical molded product 20 is in a state of being molded by a resin material as a molten material that is injection-molded in the space portion (cavity) formed in (1). After the proper resin cooling is completed, as shown in FIG. 7, the pin gate 5b is gate-cut by the mold opening operation of the injection molding machine, and the fixed side mold plate 4 and the runner dropping plate 6 are isolated. At the same time, the fixed-side core member 5 is moved toward the fixed-side mounting plate 3 by the bias of the spring 32, so that the end molding surface of the fixed-side core member 5 from the inner peripheral portion 20b of the molded product 20 shown in FIG. Evacuates. At this time, the movement amount of the fixed-side core member 5 is regulated by a stop pin 9 screwed to the fixed-side template 4.
[0030]
Next, as shown in FIG. 8, the mold opening operation of the injection molding machine continues, and the core holding plate 12 and the movable side mounting plate 13 are integrally formed with respect to the slide holding plate 11 while the PL is closed. Leave in the opening direction. At this time, the core rod 14 attached to the core holding plate 12 is separated (moved) relative to the first slide member 15 and the second slide member 16, and at the same time, the circumferential protrusion of the first slide member 15. 15a, since the circumferential protrusion 16a of the second slide member 16 is guided by the slide holding plate 11, the first slide member 15 and the second slide member 16 are in the radial center direction (the direction toward the axis of the core rod 14). ) Accordingly, the screw transfer portions 15b and 16b (see FIG. 1) that form helicoid screws that are undercut of the first slide member 15 and the second slide member 16 are detached from the inner peripheral portion 20b of the cylindrical molded product 20. The mold opening operation shown in FIGS. 6 to 8 corresponds to the mold opening initial operation.
[0031]
Further, the mold opening operation of the injection molding machine proceeds, and as shown in FIG. 9, the magnet 18 is attracted and the PL is opened. At this time, since the outer slide member 17 does not move until the tapered portion 21b of the angular cam 21 planted on the fixed-side template 14 contacts the tapered hole 17a of the outer slide member 17, the outer periphery of the cylindrical molded product 20 is not moved. The cylindrical molded product 20 is held by the movable mold 2 by the undercut portion 20 c and is detached from the hole molding surface 4 a of the fixed mold 4.
[0032]
Further, when the mold opening operation of the injection molding machine proceeds, as shown in FIG. 10, the movement between the movable mold 2 and the fixed mold 1 is restricted by the tension link 35, and at this time, the taper of the angular cam 21. Since the portion 21b presses the tapered hole 17a of the outer slide member 17, the outer slide member 17 releases the fixed holding state of the outer peripheral undercut portion 20c of the cylindrical molded product 20, and the runner drop plate 6 is fixed to the fixed side. The mounting plate 3 opens by the amount of regulation by the stop pin 30a, and the runner lock pin 8 comes out of the runner 5a. In this state, the mold opening operation is completed. The mold opening operation shown in FIGS. 9 and 10 corresponds to the mold opening latter half operation.
[0033]
FIG. 11 shows a protruding state for further taking out the cylindrical molded product 20. In this example, the protruding rod 34 is pushed out by a protruding mechanism (not shown) of the injection molding machine toward the fixed side mold plate 4. The stripper plate 10 is moved. Due to the movement of the stripper plate 10, the distance between the slide holding plate 11 and the stripper plate 10 is widened, and the cylindrical molded product 20 with respect to the first slide member 15 and the second slide member 16 held on the slide holding plate 11. Will move in the direction of movement of the stripper plate 10. As the cylindrical molded product 20 moves, the length of the first slide member 15 and the second slide member 16 that are in the inside of the cylindrical molded product 20 is reduced. It can be easily removed from the stripper plate 10. Of course, even in the state up to FIG. 10, this operation is not necessary if the cylindrical molded product 20 can be taken out. By the above operation, the cylindrical molded product can be molded without causing deformation or scratches.
[0034]
According to the present embodiment, without changing the conventional molding cycle, it is possible to damage the cylindrical molded product having the molded undercut portions on the inner and outer peripheral portions by the sequential movement of each mold component when the mold is opened. It can be taken out from the injection mold without giving any deformation, and the quality in mass production can be stabilized.
[0035]
(Embodiment 2)
12 to 15 show the second embodiment, FIG. 12 is a longitudinal sectional view of an injection molding die of a cylindrical molded product, FIG. 13 is a longitudinal sectional view of an injection molding die in a closed state, and FIG. 14 is a first stage. FIG. 15 is a longitudinal sectional view of the injection mold in the mold opening state, and FIG. 15 is a longitudinal sectional view of the injection mold in the second stage of the mold opening state. The present embodiment is different from the first embodiment in that the molded cylindrical molded product remains in the fixed mold, and the other parts are the same as those in the first embodiment. Are denoted by the same reference numerals and description thereof is omitted.
[0036]
In the injection mold according to the present embodiment shown in FIG. 12, in the cylindrical molded product 20 shown in FIG. 4, the outer undercut portion 20c formed on the outer peripheral portion is molded to the outer slide attached to the fixed side mold plate 4. The member 17 is formed. Therefore, with respect to the first embodiment, the arrangement position of the outer slide member 17 that forms the outer peripheral undercut portion 20c formed on the outer peripheral portion of the cylindrical molded product 20 is on the fixed mold 1 side. Moreover, the part which shape | molds the outer peripheral part 20a of the molded article 20 becomes the stripper plate 10 in the movable side metal mold | die 2, and the fixed side core member 5 in FIG. 1 is not used.
[0037]
In FIG. 12, as in the first embodiment, the fixed-side mold 1 has a fixed-side mold plate 4, a runner dropping plate 6, and a fixed-side mounting plate 3, and is implanted in the fixed-side mounting plate 3. The runner dropping plate 6 and the fixed side template 4 are slidably fitted to the support pins 36a. Further, stop pins 30a and 30b having stepped heads are screwed onto the runner drop plate 6 from different directions, and the fixed side mold plate 4, the runner drop plate 6 and the fixed side attachment 3 are not shown in the drawing. A predetermined amount can be isolated in the mold opening direction of the molding machine. The fixed-side template 4 functioning as a slide holding member includes an outer slide member 17 (functioning as a work holding means) that forms the outer peripheral undercut portion 20c of the cylindrical molded product 20 so as to be slidable in the radial direction. . PL is an abbreviation for parting line, and indicates a contact surface between the fixed-side template 4 and the stripper plate 10. Therefore, it can be said that it is a parting surface on which the plates of the movable mold 2 and the fixed mold 1 abut. Hereinafter, it is abbreviated as PL.
[0038]
The stripper plate 10 of the movable mold 2 is provided with an angular cam 21. As shown in FIG. 5, the angular cam 21 has a straight portion 21a and a tapered portion 21b, and the straight portion 21a side is a stripper plate. 10 is planted. The tapered portion 21 b of the angular cam 21 is configured to enter each of the holes of the stationary side mold plate 4 and the runner dropping plate 6 formed at positions corresponding to the tapered holes 17 a of the outer slide member 17. In the initial stage of mold clamping, the taper portion 21b (specifically, the taper surface of the taper hole 17a) is formed in the taper hole 17a of the outer slide member 17 (specifically, the surface portion facing the taper surface of the taper hole 17a). The outer slide member 17 is moved in the circumferential inner direction by the taper fitting of the taper portion 21b on the opposite side), and the slide member 17 is stopped by the straight portion 21a (see FIG. 5) in the latter half of the mold clamping operation. To do. Further, the stripper plate 10 is a circular hole-shaped hole forming surface 10b for forming the outer peripheral portion 20a of the cylindrical molded product 20, that is, for forming an outer peripheral surface without the outer peripheral undercut portion 20c of the cylindrical molded product 20. It functions as a cavity member. Further, magnets 18 and 18 as fastening means are respectively attached to the side surface of the fixed side mold plate 4 (slide holding member) of the fixed side mold 1 and the side surface of the stripper plate 10 of the movable side mold 2. . Other configurations of the injection mold are the same as those in the first embodiment.
[0039]
Next, an injection molding method of a cylindrical molded product using the injection mold having the above-described configuration will be described with reference to FIGS. FIGS. 13 to 15 sequentially show the molding steps of the injection mold attached to the injection molding machine, and the illustration of the injection molding machine is omitted. FIG. 13 shows a state in which the mold is closed, and is a state in which the cylindrical molded product 20 is molded as in the first embodiment. After the proper resin cooling is completed, as shown in FIG. 14, the pinpoint gate 5b is gate-cut by the mold opening operation of the injection molding machine, and the fixed side mold plate 4 and the runner dropping plate 6 are isolated. Further, the mold opening operation of the injection molding machine continues, and the core holding plate 12 and the movable side mounting plate 13 are detached from the slide holding plate 11 integrally in the mold opening direction while the PL is closed. Thereafter, when the core rod 14 as the center core moves backward in the mold opening direction, the first slide member 15 and the second slide member 16 are moved by the circumferential protrusions 15a and 16a of the first slide member 15 and the second slide member 16, respectively. Moves toward the axis of the core rod 14, and the screw transfer portions 15 b and 16 b (see FIG. 12) of the first slide member 15 and the second slide member 16 are detached from the inner peripheral portion 20 b of the cylindrical molded product 20. The mold opening operation in FIGS. 13 and 14 corresponds to the mold opening initial operation.
[0040]
Further, when the mold opening operation of the injection molding machine proceeds, the parting surfaces (PL surfaces) of the movable mold 2 and the fixed mold 1 are opened, and before the stripper plate 10 and the fixed side are formed, as shown in FIG. The template 4 is isolated, and at the initial stage of the isolation, the straight portion of the tapered hole 17a of the outer slide member 17 moves relatively along the straight portion 21a (see FIG. 5) of the angular cam 21. Since the outer slide member 17 does not move, the outer peripheral undercut portion 20c of the cylindrical molded product 20 is retained by a hook-shaped step portion 17b (see FIG. 5) formed inside the outer slide member 17. The molded product 20 is held by the fixed-side mold plate 4. In this state, the outer peripheral portion 20a of the cylindrical molded product 20 is a circular hole-shaped hole forming surface 10b of the stripper plate 10 (FIG. 12). Contact state is moved is released from the irradiation). When mold opening proceeds from this state, as shown in FIG. 15, the tapered hole 17a of the outer slide member 17 is pushed by the tapered portion 21b of the angular cam 21, and the outer slide member 17 moves outward in the radial direction. Detach from the cylindrical molded product 20.
[0041]
Further, when the mold opening operation of the molding machine proceeds, the runner lock pin 8 comes out of the runner 5a formed on the fixed side mold plate 4 as shown in FIG. The mold opening operation is completed in this state. The mold opening operation up to FIG. 15 corresponds to the mold opening latter half operation.
[0042]
According to the present embodiment, in addition to the same effects as those of the first embodiment, the cylindrical molded product is not left in the movable mold, but is held in the fixed mold, so that it is arranged in the movable mold. It is not necessary to use the cylindrical cylindrical product ejection mechanism (the ejection rod 34 and the ejection means provided in the injection molding machine in FIG. 1 of Embodiment 1), and the mold structure can be simplified.
[0043]
【The invention's effect】
Claims 1 and 2 According to the invention, the cylindrical molded product can be molded and contracted in the axial direction, the pressing force to the cavity member side of the outer peripheral portion of the molded product is reduced, and one end side of the outer peripheral portion of the cylindrical molded product is held by sliding. Since the cylindrical molded product can be easily detached from the cavity member by holding it with the work holding means attached to the member and pulling out most of the outer periphery of the molded product from the hole forming surface of the cavity member, Without changing the molding cycle, scratches and deformation of the cylindrical molded product can be reduced, and the quality in mass production can be stabilized.
[0046]
Claim 2 According to the invention, in addition to the above effects, the undercut portion is formed on the outer peripheral portion of the cylindrical molded product, and the cylindrical molded product is reliably detached from the cavity member by using the undercut portion. Deformation and scratches due to the cylindrical molded product and the cavity member can be reliably prevented.
[0047]
Claim 3 According to the invention, the release of the cylindrical molded product and each member of the injection mold is made smooth, and the cylindrical molded product is held in the fixed side mold or the movable side mold so that it can be easily taken out. It is possible to reliably prevent deformation and scratches of the formed cylindrical product and stabilize the quality in mass production.
[0048]
Claim 4 According to the invention, since the release of the cylindrical molded product and each member of the injection mold is made smooth and the cylindrical molded product is held in the work holding means so as to be easily taken out, the deformation of the molded cylindrical molded product It is possible to reliably prevent scratches, stabilize the quality in mass production, and handle cylindrical molded products easily.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an injection mold of a cylindrical molded product according to a first embodiment.
FIG. 2 is a perspective view of a first slide member according to the first embodiment.
FIG. 3 is a perspective view of a core rod according to the first embodiment.
4 is a longitudinal sectional view of a cylindrical molded product according to Embodiment 1. FIG.
FIG. 5 is a longitudinal sectional view showing engagement between the angular cam and the outer slide member according to the first embodiment.
6 is a longitudinal sectional view of the injection mold in the mold closed state according to the first embodiment. FIG.
FIG. 7 is a longitudinal sectional view of the injection mold in the mold opening state in the first stage of the first embodiment.
FIG. 8 is a longitudinal sectional view of the injection mold in the mold opening state in the second stage of the first embodiment.
9 is a longitudinal sectional view of the injection mold in the third stage of the mold opening state of the first embodiment. FIG.
FIG. 10 is a longitudinal sectional view of an injection mold in the mold opening state at the final stage of the first embodiment.
FIG. 11 is a longitudinal sectional view of an injection molding die in a protruding state of a cylindrical molded product according to the first embodiment.
12 is a longitudinal sectional view of an injection mold for a cylindrical molded product according to Embodiment 2. FIG.
FIG. 13 is a longitudinal sectional view of the injection mold in the mold closed state according to the second embodiment.
14 is a longitudinal sectional view of an injection mold in a mold opening state in the first stage of the second embodiment. FIG.
FIG. 15 is a longitudinal sectional view of an injection mold in a mold opening state in the second stage of the second embodiment.
16 is a plan view of a core in an injection molding state attached to a conventional mold as seen from the y direction in FIG. 17;
17 is a cross-sectional view through an axis along the line ww of FIG. 16 of the prior art.
FIG. 18 is a view showing positions of components of a molding die attached with a conventional open core in a first stage of mold opening.
FIG. 19 is a diagram showing the positions in the mold opening second stage of the components of the molding die attached with the conventional open core.
FIG. 20 is a diagram showing positions of components of a molding die attached with a conventional open core in a third stage of mold opening.
[Explanation of symbols]
1 Fixed mold
2 Movable mold
4 Fixed side template
10 Stripper plate
14 Core stick
15 First slide member
16 Second slide member
17 Outer slide member

Claims

対向する可動側金型および固定側金型のパーティング面を当接させた型閉じ状態において生じる空間部によって円筒成形品を成形する射出成形型において、
前記円筒成形品の内周部を成形するように前記可動側金型に取り付けられ、それぞれが組み合わされたときにその外周面が円筒状となる複数のコア部材と、
前記円筒成形品の外周部を成形するように前記可動側金型または前記固定側金型の構成要素として用いられるとともに、前記複数のコア部材の外周面と対向する円形孔状の孔成形面を形成したキャビティ部材と、
前記可動側金型および前記固定側金型が閉じた状態で形成される前記複数のコア部材の外周面と前記キャビティ部材の孔成形面との間の前記空間部に溶融材料を射出充填した後から、前記パーティング面を離反させる前までである型開き初期動作時に前記可動側金型と前記固定側金型とを締結し、前記パーティング面を離反させたとき以降である型開きの後半動作時に前記可動側金型と前記固定側金型との締結を開放する締結手段と、
前記型開き初期動作時に前記複数のコア部材のすべてを前記円筒成形品の内周部より退避位置に移動させるセンタコアと、
前記型開き後半動作時に前記円筒成形品の外周部を保持するように前記キャビティ部材と対向して配置されるスライド保持部材に取り付けられたワーク保持手段と、を具備することを特徴とする円筒成形品の射出成形型。In an injection mold for molding a cylindrical molded product by a space portion generated in a mold closed state in which the facing movable part mold and the parting surface of the fixed mold are in contact with each other,
A plurality of core members that are attached to the movable mold so as to mold the inner peripheral part of the cylindrical molded product, and whose outer peripheral surfaces are cylindrical when they are combined,
A circular hole-shaped hole forming surface that is used as a component of the movable mold or the fixed mold so as to mold the outer peripheral portion of the cylindrical molded product and that faces the outer peripheral surfaces of the plurality of core members. A formed cavity member;
After the molten material into the space between the outer peripheral surface and the hole forming surface of the cavity member of the plurality of core members, wherein the movable mold and the fixed mold is formed in a closed injected and filled From the second half of the mold opening after the parting surface is separated after the movable side mold and the stationary side mold are fastened during the initial stage opening operation before the parting surface is separated. Fastening means for releasing the fastening between the movable mold and the fixed mold during operation;
A center core for moving all of said plurality of core members at the initial opening operation the mold to the retreat position from the inner circumferential portion of the cylindrical molded article,
And a workpiece holding means attached to a slide holding member arranged to face the cavity member so as to hold the outer peripheral portion of the cylindrical molded product during the latter half of the mold opening operation. Product injection mold.

前記ワーク保持手段は、前記円筒成形品の外周部に凸または凹となる外部アンダーカット部を形成する複数の外スライド部材から構成され、前記可動側金型が型開きを開始するまで前記外部アンダーカット部を介して前記円筒成形品を前記スライド保持部材に保持させることを特徴とする請求項１記載の円筒成形品の射出成形型。 The work holding means is composed of a plurality of outer slide members that form convex or concave external undercut portions on the outer peripheral portion of the cylindrical molded product, and the external under-molding is performed until the movable mold starts to open the mold. The injection molding die for a cylindrical molded product according to claim 1, wherein the cylindrical molded product is held by the slide holding member through a cut portion.

対向する可動側金型および固定側金型のパーティング面を当接させた型閉じ状態において生じる空間部によって円筒成形品を成形する射出成形方法において、
前記円筒成形品の内周部を成形するように前記可動側金型に取り付けられ、それぞれが組み合わされたときにその外周面が円筒状となる複数のコア部材と、
前記円筒成形品の外周部を成形するように前記可動側金型または前記固定側金型の構成要素として用いられるとともに、前記複数のコア部材の外周面と対向する円形孔状の孔成形面を形成したキャビティ部材と、
前記円筒成形品の一方の端部側を成形するように前記キャビティ部材に対向して配置されたスライド保持部材と、を、前記可動側金型および前記固定側金型を型閉じ状態にして前記パーティング面を当接させて、前記複数のコア部材の外周面と前記キャビティ部材の孔成形面との間に前記空間部を形成し、
その後、前記空間部に溶融材料を射出充填し、
しかる後、前記パーティング面の当接を締結したまま前記コア部材の外周面を前記円筒成形品の軸心に向けて移動させて、該円筒成形品の内周部より前記複数のコア部材のすべての外周面を退避させた後、
前記可動側金型と前記固定側金型との締結を解除して前記パーティング面を離反させて前記円筒成形品の外周部を前記キャビティ部材の孔成形面から離脱し、前記円筒成形品を前記キャビティ部材を有しない固定側金型または可動側金型に保持したまま型開き動作を完了させ、前記円筒成形品を取り出すことを特徴とする円筒成形品の射出成形方法。In an injection molding method for molding a cylindrical molded product by a space portion generated in a mold closed state in which the facing movable part mold and the parting surface of the fixed mold are brought into contact with each other,
A plurality of core members that are attached to the movable mold so as to mold the inner peripheral part of the cylindrical molded product, and whose outer peripheral surfaces are cylindrical when they are combined ,
Together used as the components of the movable die or the stationary die so as to mold the outer peripheral portion of the cylindrical molded article, the outer peripheral surface and the circular Katachiana shaped hole forming surface facing said plurality of core members A cavity member formed with,
A slide holding member disposed opposite to the cavity member so as to mold one end side of the cylindrical molded product, and the movable side mold and the fixed side mold are in a mold-closed state. Contacting the parting surface to form the space between the outer peripheral surface of the plurality of core members and the hole forming surface of the cavity member;
After that, the molten material is injected and filled into the space,
Thereafter, the still entered into abutting parting surface of the outer peripheral surface of the core member is moved toward the axis of the cylindrical molded article, the plurality of core members from the inner peripheral portion of the cylindrical molded article After retracting all the outer peripheral surfaces,
The fastening between the movable side mold and the fixed side mold is released to separate the parting surface, so that the outer peripheral portion of the cylindrical molded product is separated from the hole molding surface of the cavity member, and the cylindrical molded product is removed. An injection molding method for a cylindrical molded product, wherein a mold opening operation is completed while being held by a fixed mold or a movable mold without the cavity member, and the cylindrical molded product is taken out.

前記円筒成形品を前記キャビティ部材を有しない固定側金型または可動側金型に保持したまま型開き動作を完了させ、前記円筒成形品を取り出すことに替えて、前記円筒成形品を前記スライド保持部材に取り付いたワーク保持手段に保持したまま型開き動作を完了させ、前記円筒成形品を取り出すことを特徴とする請求項３記載の円筒成形品の射出成形方法。 The cylindrical molded product is held by the slide holding instead of completing the mold opening operation while holding the cylindrical molded product in the fixed side mold or the movable side mold without the cavity member. 4. The method of injection molding a cylindrical molded product according to claim 3, wherein the mold opening operation is completed while being held by the work holding means attached to the member, and the cylindrical molded product is taken out.