JP3761278B2 - Long shaft member and mold for molding - Google Patents

Long shaft member and mold for molding Download PDF

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Publication number
JP3761278B2
JP3761278B2 JP5738997A JP5738997A JP3761278B2 JP 3761278 B2 JP3761278 B2 JP 3761278B2 JP 5738997 A JP5738997 A JP 5738997A JP 5738997 A JP5738997 A JP 5738997A JP 3761278 B2 JP3761278 B2 JP 3761278B2
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Prior art keywords
main body
cavity
forming
hollow
shaft
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JP5738997A
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JPH10138367A (en
Inventor
明則 田名田
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Ricoh Co Ltd
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Ricoh Co Ltd
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Priority to JP5738997A priority Critical patent/JP3761278B2/en
Priority to US08/820,421 priority patent/US6159415A/en
Priority to CN97109514A priority patent/CN1083325C/en
Priority to CNB001325531A priority patent/CN1139472C/en
Publication of JPH10138367A publication Critical patent/JPH10138367A/en
Priority to US09/172,137 priority patent/US6117018A/en
Priority to CN00132554.XA priority patent/CN1231342C/en
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Publication of JP3761278B2 publication Critical patent/JP3761278B2/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/1703—Introducing an auxiliary fluid into the mould
    • B29C45/1704—Introducing an auxiliary fluid into the mould the fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles

Description

【０００１】
【発明の属する技術分野】
本発明は、合成樹脂材料により形成され、かつ、中心軸と略同心で該中心軸の延びる方向に長く延びる中空部を内部に有し、しかも、前記中空部の延びる方向の両端に中空部を外部に連通する貫通穴が形成され、該貫通穴が前記中心軸と略同心である長軸部材に関する。更に詳しくは、中心軸と略同心で該中心軸の延びる方向に長く延びる中空部を内部に有する本体部の両端に小径の軸部が形成され、その軸部に中空部を外部に連通する貫通穴が形成され、その貫通穴が中心軸と略同心の長軸部材及びその成形用金型に関する。とりわけ、本体部の外周にはトナー等の搬送用スクリュが形成された長軸部材の成形に好的の成形用金型に関する。
【０００２】
【従来の技術】
長軸部材を合成樹脂製の丸棒から切削加工すると、この長軸部材の製造に使用する合成樹脂材料のコストが高くなると共に、長軸部材の重量が重くなる。また、トナー等の搬送に使用する長軸部材では、本体部の外周にトナー等の搬送用スクリュを構成する螺旋状の突起部を複数個間隔を開けて設け、その本体部の軸方向両端部には軸部を設けなければならないため、物品形状が複雑である。このような、長軸部材を合成樹脂製の丸棒から切削加工すると、物品形状が複雑なため、加工工数が多くかかり、それだけ製品コストが高くなる。
【０００３】
そこで、この種の長軸部材全体を一体成形する技術が知られている（特開平５−２０８４６０号公報参照）。この技術（ガスインジェクション法）では、図３２に示すように、成形用金型の成形品キャビティ１のほぼ中心軸Ｏ０の延長線上に溶融状態の合成樹脂材料を供給するゲート２が設けられ、ゲート２に対してほぼ直角方向からガス供給管（ガス供給ノズル）３がゲート２に連通されている。
【０００４】
この技術では、成形品キャビティ１に注入される溶融状態の合成樹脂量を所定量計量し、ゲート２から溶融状態の合成樹脂材料４を供給した後に、ガス供給管３から溶融状態の合成樹脂材料４内に加圧ガスを注入する。すると、溶融状態の合成樹脂材料４が加圧ガスの圧力により成形用金型の内面全体に押し付けられかつ行き渡る。これにより、成形用金型の内面形状と同形状の外面形状を有する中空形状の長軸部材が形成される。
【０００５】
すなわち、図３３に示すように、中心軸Ｏ１の延びる方向に長く延びた中空部５を有する本体部６と、この本体部６の両端にこの本体部６よりも小径の軸部７とを備えた長軸部材８が形成される。
【０００６】
【発明が解決しようとする課題】
しかしながら、この種の技術により成形された長軸部材８は、ガス供給管３から供給された加圧ガスがほぼ直角に屈曲して成形品キャビティ１に流入するので、成形品としての長軸部材８に偏肉による曲がり変形が発生し易い。また、一対の軸部７のうち、一方の軸部７の外周面に、中空部５を外部に連通する貫通穴９が加圧ガスの供給に基づき発生するため外観上好ましくない。
【０００７】
また、この長軸部材８の軸部７には回転動力を受けるため金属製シャフトが用いられることがある。一端部に金属製シャフト７が設けられた長軸部材８の成形の場合には、例えば、図３４に示すように、成形品キャビティ１のゲート２から遠い側に金属製シャフト７をインサートし、図３２に示すゲート２から溶融状態の合成樹脂材料４を注入した後に、ガス供給管３から加圧ガスを供給する。しかしながら、成形サイクル毎に実際に計量された溶融樹脂の量にはばらつきがある。
【０００８】
この計量のばらつきに基づき中空率が変動する。すなわち、この成形用金型には、成形品体積の約３０％の中空率となるように、溶融樹脂をキャビティ容積の７０％を計量して注入している。従って、溶融樹脂の計量が多い場合には、成形品キャビティ１のゲート２から遠い金属製シャフト７の近傍に溶融状態の合成樹脂材料４の溜り部１０が生じ、この溜り部１０の溶融状態の合成樹脂材料が固化しにくく、型成形サイクル時間が長引いて、製品コストが高くなる問題が発生する。また、この溜り部１０の溶融状態の合成樹脂材料が固化する際に、溜り部１０の収縮量が大きいために、成形品が変形し、寸法精度が悪くなる。また、その溜り部１０の溶融状態の合成樹脂材料が硬化した際に、完成した長軸部材８では、その部分が厚肉部となり、好ましくない。
【０００９】
一方、溶融樹脂の計量が少ない場合には、ゲート２から遠い金属製シャフト７近傍の肉厚が薄くなる。
【００１０】
長軸部材８の両端部に金属製のシャフト７をインサート成形する場合には、図３０に示すように、ゲート２、ガス供給管３を中心軸Ｏ０に対して直交する方向に設けなければならない。この場合にも、ガス供給管３から供給された加圧ガスがほぼ直角に屈曲して、成形品キャビティ１に流入することになるため、成形品に偏肉による変形を生じる。また、ゲート２から遠い側の金属製シャフト７の近傍に溜り部１０が発生するため、同様の問題がある。
【００１１】
本発明は、上記の事情に鑑みて為されたもので、一体成形により製作可能でかつ外観上の見栄えが良好でしかも安価で、重量も軽く、曲がり変形の少ない長軸部材及びその長軸部材の成形に使用する成形用金型を提供することにある。
【００１２】
【課題を解決するための手段】
請求項１に記載の長軸部材は、合成樹脂材料により形成された本体部が中心軸と略同心で該中心軸の延びる方向に長く延びる中空部を内部に有し、前記本体部の両端部に該本体部よりも小径の第１、第２軸部が形成され、前記各軸部には前記中空部を外部に連通する貫通穴が形成され、該貫通穴が前記中心軸と略同心であり、前記軸部が前記本体部の少なくとも一方の端部にインサートされた金属製のインサート部材により形成され、前記貫通穴が前記インサート部材に形成され、該インサート部材は前記貫通穴を構成する内周壁が前記本体部を形成する合成樹脂材料で被覆されていることを特徴とする。
請求項２に記載の長軸部材は、前記貫通穴の直径が前記インサート部材の外部に露呈している端面から前記本体部に埋め込まれている端面までに渡って連続的に大きくなっていることを特徴とする。
請求項３に記載の長軸部材は、前記本体部の外周面にその長手方向に沿って螺旋状の突起部が間隔を開けて複数個形成されていることを特徴とする。
請求項４に記載の長軸部材は、前記本体部の外周面にはその長手方向に沿って螺旋状の突起部が間隔を開けて複数個形成される長手方向突起形成領域が設けられ、該長手方向突起形成領域は前記本体部の周回り方向所定の角度範囲内の突起形成部と、前記所定の角度範囲外の突起非形成部とを有し、該突起非形成部の断面肉厚と前記突起形成部の断面肉厚とが略同一となるように、前記突起非形成部に前記突起形成部の外周面より低い外周面が形成されていることを特徴とする。
請求項５に記載の長軸部材の成形用金型は、合成樹脂材料により形成された本体部が中心軸と略同心で該中心軸の延びる方向に長く延びる中空部を内部に有し、前記本体部の両端部に該本体部よりも小径の第１、第２軸部が形成され、前記各軸部には前記中空部を外部に連通する貫通穴が形成され、該貫通穴が前記中心軸と略同心であり、前記軸部が前記本体部の少なくとも一方の端部にインサートされた金属製のインサート部材により形成され、前記貫通穴が前記インサート部材に形成され、該インサート部材は前記貫通穴を構成する内周壁が前記本体部を形成する合成樹脂材料で被覆されているものであって、前記本体部の中心軸に対応するキャビティ中心軸を有して前記本体部を成形する本体部キャビティと、前記本体部の両端部に形成された軸部を成形するための第１、第２軸部キャビティと、前記中空部を形成するための中空形成媒体を前記第１軸部キャビティを通じて注入する媒体注入部と、前記媒体注入部よりもキャビティ側に設けられて溶融樹脂を注入する樹脂注入部と、前記キャビティ内に充填された溶融樹脂のうち前記中空形成媒体の注入により該キャビティ内で余分となる余分樹脂を前記第２軸部キャビティを通じて受け入れる余分樹脂受入キャビティと、該余分樹脂受け入れキャビティを外部に連通する中空形成媒体流出部と、該中空形成媒体流出部を開閉する開閉バルブとを有することを特徴とする。
請求項６に記載の長軸部材の成形用金型は、前記樹脂注入部は前記中空媒体の注入される方向と交差される方向から溶融樹脂が注入されるように配置されていることを特徴とする。
請求項７に記載の長軸部材の成形用金型は、前記第１、第２軸部キャビティの少なくとも一方が、貫通穴を有するインサート部材の設置部とされていることを特徴とする。
請求項８に記載の長軸部材の成形用金型は、合成樹脂材料により形成された本体部が中心軸と略同心で該中心軸の延びる方向に長く延びる中空部を内部に有し、前記本体部の両端部に該本体部よりも小径の第１、第２軸部が形成され、前記各軸部には前記中空部を外部に連通する貫通穴が形成され、前記貫通穴が前記中心軸と略同心で、前記軸部が前記本体部の少なくとも一方の端部にインサートされた金属製のインサート部材により形成され、前記貫通穴が前記インサート部材に形成され、該インサート部材は前記貫通穴を構成する内周壁が前記本体部を形成する合成樹脂材料で被覆されているものであって、前記本体部の中心軸に対応するキャビティ中心軸を有して前記本体部を成形する本体部キャビティと、前記本体部の両端部に形成された軸部を成形するための第１、第２軸部キャビティと、前記第１軸部キャビティを介して前記本体部キャビティに前記中空部を形成するための ガスを注入するガス注入部と、前記ガス注入部よりもキャビティ側に設けられて前記ガスの注入方向と交差する方向から溶融樹脂を注入する樹脂注入部と、前記キャビティ内に充填された溶融樹脂のうち前記ガスの注入により該キャビティ内で余分となる余分樹脂を受け入れるために前記第２軸部キャビティを介して前記本体部キャビティと連通された余分樹脂受入キャビティと、該余分樹脂受け入れキャビティを外部に連通する中空形成媒体流出部と、該中空形成媒体流出部を開閉する開閉バルブとを有することを特徴とする。
【００２６】
【発明の実施の形態】
以下に本発明に係わる長軸部材及びその成形用金型をその長軸部材の成形装置及びその成形方法と共に説明する。
【００２７】
【実施例１】
図１において、２０は長軸部材である。この長軸部材２０は合成樹脂材料により形成された円筒状の本体部２１を有する。この本体部２１は中心軸Ｏ１と略同心で中心軸Ｏ１の延びる方向に長く延びる中空部２２を内部に有する。本体部２１の両端部には本体部２１よりも小径の円筒状の第１、第２軸部２３が形成されている。各軸部２３には中空部２２を外部に連通する貫通穴２４が形成されている。この貫通穴２４は中心軸Ｏ１と略同心である。本体部２１の外周には搬送用スクリュを構成する螺旋状の突起部２５が間隔を開けて複数個形成されている。貫通穴２４は後述する成形用金型に溶融状態の合成樹脂材料を注入した後、中心軸Ｏ１に平行な方向からガスインジェクション法により中空形成媒体としてのガスを注入することによって形成される。中空形成媒体としては、ガス（気体）の他、液体を用いることもできる。
【００２８】
図２は図１に示す長軸部材２０の成形用金型を示し、その図２において、２６は固定型、２７は可動型である。この固定型２６と可動型２７との間に本体部２１に対応する本体部キャビティ（成形品キャビテイ）２８が形成されている。この本体部キャビティ２８は、本体部２１の中心軸Ｏ１に対応するキャビティ中心軸Ｏ２を有する。この本体部キャビティ２８の両端部には、合成樹脂材料からなる第１、第２軸部に対応して第１、第２軸部キャビティ（成形品キャビティ）２９、３０が形成されている。本体部キャビティ２８の一方の端部には、ガス圧源からのガスを本体部キャビティ２８に注入するガスノズル（媒体注入部）３２が中心軸Ｏ２と略同心に設けられている。また、本体部キャビティ２８に溶融状態の合成樹脂材料を注入するための樹脂注入部３１がガスノズル３２とキャビティ２９との間に形成されている。固定型２６には樹脂注入部３１にガスノズル３２からのガスの注入方向と交差する方向（直交する方向）から溶融状態の合成樹脂材料を注入する注入通路３３が形成されている。本体部キャビティ２８の他方の端部には樹脂注入部３１から注入された溶融状態の合成樹脂材料の余分を受け入れる余分樹脂受入キャビティ３４が形成されている。余分樹脂受入キャビティ３４は、接続通路３５、第２軸部キャビティ３０を挟んで本体部キャビティ２８に連通されている。余分樹脂受入キャビティ３４は中心軸Ｏ１と略同心である。本体部キャビティ２８にはその内周壁に突起部２５を形成するための凹所３６が形成されている。
【００２９】
この成形用金型には、溶融状態の合成樹脂材料が注入通路３３を介して樹脂注入部３１に注入され、中心軸Ｏ２方向からガスが本体部キャビティ２８に供給される。溶融状態の合成樹脂材料４は加圧ガスの圧力により本体部キャビテイ２８の内面全体に押し付けられながら、余分樹脂受入キャビティ３４の側に向かって移動される。長軸部材２０として用いられない余分の溶融状態の合成樹脂材料はガスの圧力により余分樹脂受入キャビティ３４に向かって中心軸方向から押し出されるので、本体部キャビティ２８の内面全体に溶融状態の合成樹脂材料４がほぼ均一に行き渡る。これにより、図３に示すように、成形用金型の内面形状と同形状の外面形状を有する中空状の成形品２０´が形成される。
【００３０】
この成形品２０´は樹脂注入部３１に対応する肉部３１´、接続部３５に対応する肉部３５´、余分樹脂受入キャビティ３４に対応する余肉部３４´を有する。長軸部材２０はその成形品２０´を矢印Ａ、Ａ箇所で切断することにより完成される。
【００３１】
なお、この長軸部材２０の成形方法の詳細については、後述する実施例の成形方法を参照されたい。
【００３２】
【実施例２】
図４ないし図１１は本発明に係わる長軸部材２０の第２実施例である。この図４ないし図１１では、長軸部材２０の軸部２３の少なくとも一方が回転動力を受けるための金属製シャフト２３´とされている。
【００３３】
図４は本体部キャビティ２８のガスノズル３２に近い側の端部（一方の端部）に金属製シャフト２３´をインサート部材としてインサートすることにより成形された長軸部材２０を示している。図５は本体部キャビティ２８の余分樹脂受入キャビティ３４に近い側の端部（他方の端部）に金属製シャフト２３´をインサート部材としてインサートすることにより成形された長軸部材２０を示している。図６は本体部キャビティ２８の両端部に金属製シャフト２３´をインサート部材としてインサートすることにより成形された長軸部材２０を示している。金属製シャフト２３´は円筒状で、その軸方向に貫通穴２４を有している。ここでは、金属製シャフト２３´をインサート部材として用いているが、本体部２１を構成する合成樹脂材料と異なる材料をインサート部材として用いれば良く、インサート部材は金属製に限るものではない。
【００３４】
成形用金型には、図２に示すものと同じものを用いることができ、この場合、第１、第２軸部キャビティ２９、３０の少なくとも一方に金属製シャフト２３´が設置される。
【００３５】
すなわち、本体部２１の一方の端部に金属製シャフト２３´がインサートされ、本体部２１の他方の端部に第２軸部２３が合成樹脂材料により形成された長軸部材２０（図４参照）の場合には、本体部２１を成形する本体部キャビティ２８の一方の端部に存在する第１軸部キャビティ２９にインサート部材２３´が設置される。また、ガス圧源からのガスは金属製シャフト２３´の貫通穴２４を通じて本体部キャビティ２８に注入される。
【００３６】
本体部２１の他方の端部に金属製シャフト２３´がインサートされ、本体部２１の一方の端部に第１軸部２３が合成樹脂材料により形成された長軸部材２０（図５参照）の場合には、本体部２１を成形する本体部キャビティ２８の他方の端部に存在する第２軸部キャビティ３０にインサート部材２３´が設置される。また、余分樹脂受入キャビティ３４は金属製シャフト２３´の貫通穴２４を介して本体部キャビティ２８に連通される。
【００３７】
本体部２１の両方の端部に金属製シャフト２３´がインサートされた長軸部材２０の場合（図６参照）には、第１、第２軸部キャビティ２９、３０の両方にインサート部材２３´が設置される。ガスノズル３２は第１軸部キャビティ２９に設置された金属製シャフト２３´の貫通穴２４を介して本体部キャビティ２８に連通され、余分樹脂受入キャビティ３４は第２軸部キャビティ３０に設置されたインサート部材２３´の貫通穴２４を介して本体部キャビティ２８に連通される。その金属製シャフト２３´の貫通穴２４は中心軸Ｏ２と略同心に設置される。この貫通穴２４の直径は、金属製シャフト２３´の本体部２１から露出している端面から本体部２１に埋め込まれている端面までに渡って同一である。
【００３８】
この図４ないし図６に示す長軸部材２０の成形方法の概略を図７ないし図１０に示す図面を参照しつつ説明する。
【００３９】
なお、この図７ないし図１０は、本体部２１の他方の端部に金属製シャフト２３´を設けた長軸部材２０（図５を参照）の成形方法を示している。
【００４０】
まず、図７に示すように、溶融状態の合成樹脂材料４を樹脂注入通路３３から樹脂注入部３１に注入する。すると、溶融状態の合成樹脂材料４が樹脂注入部３１から第１軸部キャビティ２９を経由して本体部キャビティ２８の一方の端部に注入される。所定の量の溶融状態の合成樹脂材料４が本体部キャビティ２８に注入された状態で溶融状態の合成樹脂材料４の注入を停止する。すなわち、溶融状態の合成樹脂材料４の注入をショートショットで停止するか、あるいは、停止直前に、図８に示すように、加圧ガスをガスノズル３２から樹脂注入部３１に注入する。
【００４１】
溶融状態の合成樹脂材料４は成形用金型の接触面から熱を奪われて冷却固化する。しかしながら、溶融状態の合成樹脂材料４の中心部の冷却固化の進行度合は、接触面に較べて遅い。従って、冷却固化の遅い中心部の溶融状態の合成樹脂材料４は、加圧ガスの圧力により本体部キャビティ２８の他方の端部に向かって膨らみながら移動される。加圧ガスの圧力により、溶融状態の合成樹脂材料４は、図９に示すように、本体部キャビティ２８の他方の端部、金属製シャフト２３´の貫通穴２４、接続通路３５を経由して、余分樹脂受入キャビティ３４に向かって移動される。また、溶融状態の合成樹脂材料４は、加圧ガスの圧力により本体部キャビティ２８の内面に押し付けられ、その内部に中空部２２が形成される。中空率の変動は、余分樹脂受入キャビティ３４により吸収される。
【００４２】
溶融状態の合成樹脂材料４は金属製シャフト２３´の貫通穴２４を通じて余分樹脂受入キャビティ３４に導かれるので、金属製シャフト２３´の貫通穴２４を構成する内周壁が本体部２１と一体の合成樹脂材料４により覆われることになる。従って、本体部２１の他方の端部に存在する金属製シャフト２３´と本体部２１との接触面積が増大することになり、軸方向の引っ張り強度が増大する。
【００４３】
成形用金型から取り出された成形品２０´は、図１０に示すように、肉部３１´、３５´、余肉部３４´が一体に形成されているので、これらを切断して図５に示す長軸部材２０を形成する。
【００４４】
図１１は本体部キャビティ２８の両端部に金属製シャフト２３´をインサートして長軸部材２０（図６参照）を成形する場合の説明図を示している。この図６に示す長軸部材２０を成形する場合には、第１軸部キャビティ２９に設置された金属製シャフト２３´の貫通穴２４を通じて所定の量の溶融状態の合成樹脂材料が本体部キャビティ２８に注入される。そして、その溶融状態の合成樹脂材料の注入停止直前又は直後にガスが金属製シャフト２３´の貫通穴２４を通じて本体部キャビティ２８に注入される。第１軸部キャビティ２９に設置された金属製シャフト２３´の貫通穴２４を構成する内周壁は、本体部２１と一体の合成樹脂材料４により覆われることになる。従って、本体部２１の一方の端部に存在する金属製シャフト２３´と本体部２１との接触面積も増大することになり、その軸方向の引っ張り強度が増大する。
【００４５】
【実施例３】
図１２ないし図１５は本発明に係わる長軸部材２０の第３実施例である。この図１２ないし図１５では、長軸部材２０の軸部２３の両端部が回転動力を受けるための金属製シャフト２３´とされ、その金属製シャフト２３´の貫通穴２４の直径が金属製シャフト２３´の外部に露呈している端面から本体部２１に埋め込まれている端面までに渡って連続的に大きくなっている。すなわち、金属製シャフト２３´の貫通穴２４を構成する内周壁が円錐形状（テーパ形状）とされている。
【００４６】
この長軸部材２０を成形するには、図１３に示すように、キャビテイ２９、３０にテーパ形状の貫通穴２４を有する金属製シャフト２３´をセットする。次に、図１４を示すように、そのテーパ形状の貫通穴２４を通じて本体部キャビティ２８に溶融状態の合成樹脂材料４を注入する。貫通穴２４の断面積が本体部キャビティ２８に向かって大きくなっているので、図４、図６に示す形状の金属製シャフト２３´を用いる場合に較べて圧力損失の低減を図ることができ、溶融状態の合成樹脂材料４を所定の量だけ、確実に本体部キャビティ２８に注入することができる。
【００４７】
次に、図１５にガスを中心軸Ｏ２の方向から注入し、溶融状態の合成樹脂材料４を本体部キャビティ２８の隅ずみにくまなく行き渡らせる。このガスの注入の際にも、貫通穴２４の断面積が本体部キャビティ２８に向かって大きくなっているので、圧力損失の低減を図ることができ、ガス圧力をほとんど損失することなく、ガスを本体部キャビティ２８に注入することができる。すなわち、ガスが本体部キャビテイ２８に向かって広がりつつ注入されるので、ガスが本体部キャビティ２８にスームズに流れ込むことになる。
【００４８】
また、本体部キャビティ２８の他方の端部に存在するキャビティ３０にセットした金属製シャフト２３´では、貫通穴２４の断面積が本体部キャビティ２８の側から余分樹脂受入用キャビティ３４に向かうに伴って狭くなっているので、溶融状態の合成樹脂材料４を余分樹脂受入用キャビティ３４に押し込む際の圧力が増大し、これにより、余分の溶融状態の合成樹脂材料がスムーズに余分樹脂受入用キャビティ３４に移動される。
【００４９】
この実施例では、テーパ形状の貫通穴２４を有する金属製シャフト２３´を軸部として本体部２１の両側に設ける構成としたが、テーパ形状の貫通穴２４を有する金属製シャフト２３´をいずれか一方のみに設け、いずれか他方の軸部は合成樹脂材料から構成するようにしても良い。
【００５０】
【実施例４】
図１９、図２０は、本体部２１の外周にその長手方向に沿って形成された螺旋状の突起部２５が中心軸Ｏ１に関して円周方向に非対称の長軸部材２０を示している。この長軸部材２０の場合には、図１９に示すように、中空部２２の中心Ｏ１´と複数個の突起部２５が形成されている本体部２１の箇所の輪郭形状の中心である中心軸Ｏ１とがずれ、図２０に示すように、本体部２１の突起部欠落箇所２１´が厚肉となる傾向がある。これは、突起部形成側に溶融状態の合成樹脂材料４が多いため、突起部形成側に存在する溶融状態の合成樹脂材料４が冷却硬化されにくいからである。このため、本体部２１が弓なりとなり、長軸部材２０に曲がりを生じることがある。
【００５１】
そこで、図１６、図１７、図１８に示すように、複数個の突起部２５が形成されている本体部２１の外周面の長手方向突起形成領域２１Ａの一方から他方に渡って、肉抜き部３６を形成することとした。これにより、中空部２２の中心Ｏ１´と複数個の突起部２５が形成されている本体部２１の箇所の輪郭形状の中心とが一致するように、本体部２１の輪郭形状の中心が中心軸Ｏ１からずらされる。
【００５２】
このように、複数個の非対称の突起部２５が形成されている本体部２１の一方から他方に渡って、肉抜き部３６を形成することにすると、複数個の非対称の突起部２５が形成されている箇所では、本体部２１の肉厚が一方側から他方側に渡って均一になるので、まっすぐな長軸部材２０を成形できる。
【００５３】
すなわち、長手方向突起形成領域２１Ａには長手方向に所定間隔を開けて、周回り方向所定の角度範囲内に突起形成部２１Ｂが存在し、所定角度範囲外の箇所に突起部欠落箇所２１´としての突起非形成部が存在する。従って、長手方向突起形成領域２１Ａの突起非形成部に、突起形成部２１Ｂの基部の外周面よりも低い外周面を有する肉抜き部３６を形成すれば、この突起非形成部の断面肉厚と突起形成部の断面肉厚とが略同一となる。
【００５４】
【実施例５】
図２１は本発明に係わる長軸部材２０の成形装置の全体構成の概略図を示している。
【００５５】
この図２１において、４０は射出成形機本体（樹脂充填装置又は樹脂充填手段）を示している。この射出成形機本体４０にはホッパ４１が設けられ、ホッパ４１には固形のペレット４２が貯留されている。そのペレット４２は所定量単位でシリンダ４２ａの加圧溶融室４２ｂに供給され、スクリュロッド４２ｃにより溶融状態の合成樹脂材料４´とされる。この溶融状態の合成樹脂材料４´は固定型２６の樹脂注入通路４３、３３を通って樹脂注入部３１に導かれる。ガスノズル３２近傍の成形用金型２６、２７の部分と、本体部キャビティ２８近傍の成形用金型の部分とには、図２２に示すように、ガスノズル近傍の温度を制御するための水冷用通路（温度調節部材）４４、本体部キャビティの温度を調節するための水冷用通路（温度調節部材）４５が形成されている。水冷用通路４４に供給される冷却水の温度は５０度とされ、水冷用通路４５に供給される冷却水の温度は１０度とされている。これにより、ガスノズル３２近傍の成形用金型２６、２７の部分の冷却温度が、本体部キャビティ２８近傍の成形用金型の部分の冷却温度よりも高い温度に設定される。この温度調節部材の温度は後述する温度調節手段４０Ｂ、４０Ｃによって制御される。
【００５６】
これは、以下に説明する理由による。
【００５７】
溶融状態の合成樹脂材料４は本体部キャビティ２８の内周壁との接触によって冷却される。しかし、溶融状態の合成樹脂材料４の中心部にはガスが供給され、強制的に冷却されない。このため、本体部キャビティ２８の内周壁との接触のみに依存して、溶融状態の合成樹脂材料４を冷却することにすると、冷却時間が長くかかり、長軸部材２０の成形コストが高くなる。そこで、一般に冷却器（チラー）を用いて、成形用金型を強制的に冷却することにより成形サイクルを短縮することが行われている。
【００５８】
ところが、ガスノズル３２近傍の成形用金型の部分の温度を本体部キャビティ２８の近傍の成形用金型の部分の冷却温度と同じ温度で冷却することにすると、溶融状態の合成樹脂材料４の冷却による硬化が進み過ぎて、加圧ガスを注入しても、溶融状態の合成樹脂材料４が膨らまず、溶融状態の合成樹脂材料４に中空部が形成されないことがある。
【００５９】
そこで、長軸部材２０の成形サイクルの短縮化を図りながら、ガスノズル３２近傍の溶融状態の合成樹脂材料４の硬化速度を抑制するために、ガスノズル３２近傍の成形用金型２６、２７の部分の冷却温度を、本体部キャビティ２８近傍の成形用金型の部分の冷却温度よりも高い温度に設定した。
【００６０】
水冷用通路４５に供給する冷却水の温度を１０度に設定したわけは、これ以下の温度で、金型を冷却することにすると、溶融状態の合成樹脂材料４の冷却固化が進行し過ぎ、溶融状態の合成樹脂材料４が余分樹脂受入キャビティ３４に達しない前で、移動が止まり、所望の形状の長軸部材２０が得られないからである。
【００６１】
水冷用通路４４に供給される冷却水の温度は５０度に設定したわけは、これ以下の温度で金型を冷却することにすると、溶融状態の合成樹脂材料４の冷却固化が進行し過ぎ、加圧ガスを注入しても、溶融状態の合成樹脂材料４が膨らまず、本体部キャビティ２８に加圧ガスが注入されにくいからである。一方、これ以上の温度で金型を冷却することにすると、ガスノズル３２近傍の金型の温度が高すぎて、溶融状態の合成樹脂材料４の流動性が大きくなる。従って、ガスを注入すると、溶融状態の合成樹脂材料４がそのガスの注入により、吹き飛ばされることがあるからである。そこで、ガスノズル３２近傍の溶融状態の合成樹脂材料４の温度がガラス転移点以上の温度でかつガスの注入による吹き飛びの発生しない温度として、５０度とした。
【００６２】
成形サイクル毎の射出充填開始及び終了の制御、射出成形機本体４０、水冷用通路４４、４５への冷却水の送水制御、ガスの本体部キャビティ２８への注入及び本体部キャビティ２８からのガスを抜く制御はＣＰＵによって行われる。ＣＰＵは成形用金型の型開き、型締めに連動してこれらの制御を行う。
【００６３】
すなわち、ＣＰＵは、図２３に示すように、インプットアウトプットインターフェースを介して、射出成形機本体４０、成形用金型駆動手段４０Ａ、本体部キャビティ温度調節手段４０Ｂ、ガスノズル近傍温度調節手段４０Ｃ、ガス注入及びガス抜き手段（媒体注入装置）４０Ｄを制御する。
【００６４】
なお、温度調節手段（温度制御装置）４０Ｂ、４０Ｃは、少なくとも中空形成媒体が第１軸部キャビティ２９内に充填された溶融樹脂を通過しかつ本体部キャビテイ２８内に充填された溶融樹脂４内に注入されるまで作動させる。
【００６５】
【実施例６】
この成形装置による長軸部材２０の成形方法の詳細を以下に説明する。
【００６６】
なお、この実施例６では、図５に示す長軸部材２０を成形する場合を説明している。しかし、図１、図４、図６、図１２に示す長軸部材２０の成形にも適用できる。
【００６７】
まず、図２４（ａ）に示すように、金属製シャフト２３´を成形用金型にセットし、金型を閉じる（図２５のステップＳ１参照）。そして、次に、溶融状態の合成樹脂材料４を本体部キャビティ２８に所定圧力で注入する（図２５のステップＳ２、Ｓ３参照）。すなわち、溶融状態の合成樹脂材料４をショートショットで注入する。
【００６８】
その合成樹脂材料４には、例えばＡＢＳが用いられる。その溶融状態の合成樹脂材料４の粘度が低すぎると、加圧ガスによりその溶融状態の合成樹脂材料４の塊が突き破られ、加圧ガスが本体部キャビティ２８に漏れ出て所望の形状の成形品２０´が得られない。また、溶融状態の合成樹脂材料４の粘度が高すぎると、溶融状態の合成樹脂材料４が加圧ガスによりスムーズに膨らまず、所望の中空形状の成形品２０´が得られない。更に、完成品としての長軸部材２０´の剛性も考慮する必要がある。そこで、ここでは、ＡＢＳ樹脂にガラス繊維を混合して使用している。そのガラス繊維の含有率は３０重量％とした。そのガラス繊維の繊維長は平均３ｍｍ、繊維径は平均１３μｍである。
【００６９】
粘度の異なるＡＢＳ樹脂を用いて成形性の評価（国際的試験方法規格（略称ＡＳＴＭ））を行ったところ下記の結果を得た。
【００７０】
ここでは、テクノポリマー社製の製品名ＮＣ４１１−Ｇ３０と製品名ＮＣ１００−Ｇ３０の二種のＡＢＳ樹脂について比較を行った。いずれも、ガラス繊維の含有率は３０重量％とした。製品名ＮＣ４１１−Ｇ３０はメルトフローレートが２２０度かつ９８Ｎのもとで、１２．０ｇ／ｍｉｎであり、粘度が高い。一方、製品名ＮＣ１００−Ｇ３０はメルトフローレートが２２０度かつ９８Ｎのもとで、４０．０ｇ／ｍｉｎであり、粘度が低い。
【００７１】
この二種のＡＢＳについて、成形実験を行ったところ、合成樹脂材料４の粘度の高いＡＢＳ樹脂では、偏肉が発生した。合成樹脂材料４の粘度の低いＡＢＳ樹脂では、偏肉は発生しなかった。
【００７２】
これは、図２６（ａ）に示すように、合成樹脂材料４の粘度が高いと樹脂注入部３１近傍で、ガスの流入方向が中心軸Ｏ２に対して曲げられるからであると考えられる。一方、図２６（ｂ）に示すように、合成樹脂材料４の粘度が低いと、ガスの圧力が合成樹脂材料４の粘度に打ち勝ち、ガスの流入方向が中心軸Ｏ２と平行となるからであると考えられる。
【００７３】
この溶融状態の合成樹脂材料４の温度は例えば２４０度である。この溶融状態の合成樹脂材料４の注入量は、本体部キャビティ２８の容積の約７０％とするのが望ましいが、樹脂充填装置により注入された溶融樹脂の充填量と媒体注入装置により注入された中空形成媒体の注入量との総計が、成形用金型内に形成された本体部キャビティ２８の容積と第１、第２軸部キャビティ２９、３０の容積の総和以上であれば良い。
【００７４】
次に、図２４（ｂ）に示すように、溶融状態の合成樹脂材料４の注入停止直前又は注入停止直後に、中心軸Ｏ２の方向からガスを樹脂注入部３１に注入する。そして、溶融状態の合成樹脂材料４を膨らませつつ余分樹脂受入キャビティ３４に向かって移動させ、本体部キャビティ２８の内面全体に溶融状態の合成樹脂材料４を行き渡らせる。このガスの中心軸Ｏ２方向からの注入により、中心軸Ｏ２方向に長く延びる中空部２２が形成される。余分の溶融状態の合成樹脂材料４は余分樹脂受入キャビティ３４に導かれ、これにより、中空率の変動が吸収される。
【００７５】
ガスの圧力は、５０〜３００Ｋｇ／ｃｍ2の範囲内で選択可能であるが、ここでは、１１０Ｋｇ／ｃｍ2の圧力で注入を行った。ガス圧が低すぎると、十分な中空形状の成形品２０´を得られず、ガス圧が高すぎると、加圧ガスが溶融状態の合成樹脂材料４を突き破って、本体部キャビティ２８に漏れ出し、所望の形状の成形品２０´を得られないことになり、約１１０Ｋｇ／ｃｍ2の所定圧力を加えることが好適である。
【００７６】
そして、一定時間ガスの圧力を保持する。これにより、本体部キャビティ２８の内面全体に行き渡った溶融状態の合成樹脂材料４が冷却固化される（図２５のステップＳ４、Ｓ５参照）。ここでは、長軸部材２０の寸法精度の確保と、成形サイクルの短縮化とを比較考量して、ガスの保圧時間を４０秒に設定した。少なくとも、成形品２０´の表面がガラス転移点温度以下にまで冷却され、成形品２０´の突き出し時、成形品取出後の収縮による変形を生じない程度にまで、成形品２０´を金型内で冷却硬化させることが必要である。
【００７７】
すなわち、ガスの保圧時間と成形品２０´の寸法精度との間には、図２７（ａ）にグラフで示すような関係が得られている。その図２７（ａ）において、横軸はガスの保圧時間、縦軸は長軸部材２０の寸法精度である。ここでは、長軸部材２０の寸法精度として、長軸部材２０の回転振れを用いた。
【００７８】
すなわち、第１、第２軸部２３を基準とし、本体部２１の外周面に針を接触させ、長軸部材２０を１回転させた時の針の変化の最大量を測定した。
【００７９】
その図２７（ａ）において、符号Ｑ０は、そのガスの保圧時間と成形品２０´の寸法精度との関係を示す特性曲線であるが、保圧時間が短い領域Ｑ１では、溶融状態の合成樹脂材料４の冷却固化が不十分なので、成形品２０´を金型から取り出すと、成形品２０´が合成樹脂材料４の冷却固化により大きく変形し、成形品２０´の寸法精度が低下する。また、図２７（ｂ）に示すように、ガスノズル３２近傍の本体部キャビティ２８内の冷却固化していない溶融状態の合成樹脂材料の一部が、後述するガス抜きの際にその風圧でガスノズル３２に向かって吸い込まれ、ガスノズル３２が詰まることがある。
【００８０】
一方、保圧時間が長い領域Ｑ２では、長軸部材２０の寸法精度は向上する。しかし、成形品の収縮による金型への食い付きが大きくなり、成形品２０´の取出しの際に離型不良が発生する。従って、成形品２０´の取出しの際にそれが折れることがある。
【００８１】
従って、長軸部材２０の寸法精度と溶融状態の合成樹脂材料の硬化の進行度合とを考慮して中空部２２内のガスの保圧時間を設定する。
【００８２】
なお、ガスの保圧中に、成形機本体４０の側では、次の成形品製造のために、ペレット４２を計量する。このとき、計量精度を向上させるために、成形機本体４０側の加圧溶融室４２ｂに貯溜の溶融状態の合成樹脂材料４´にスクリュロッド４２ｃにより背圧（樹脂注入部３１の注入通路３３に溶融樹脂が停留する程度の圧力）を加えながら計量する。この背圧Ｐ０がガスの保圧圧力Ｐ１よりも高いと、図２８（ａ）に示すように、注入通路３３に存在する溶融状態の合成樹脂材料４´の一部が樹脂注入部３１に漏れ出て、貫通穴２４の一部を塞ぐことになる。従って、ガスの保圧圧力Ｐ１を背圧Ｐ０よりも大きく設定する。このように、ガスの保圧圧力Ｐ１を背圧Ｐ０よりも大きく設定すると、図２８（ｂ）に示すように、注入通路３３に存在する溶融状態の合成樹脂材料４´が注入通路３３内に押し込まれ、貫通穴２４が塞がれるのを防止できる。この停留圧力はＣＰＵ（制御装置）によって制御される。
【００８３】
すなわち、媒体注入装置４０ＤもＣＰＵによって注入圧力がコントロールされ、この圧力Ｐ１が停留圧力Ｐ０よりも高い。この媒体注入装置４０Ｄの作動は、溶融樹脂４の内面が安定するまで行われるのが好ましい。
【００８４】
その溶融樹脂４の内面の安定は、第１軸部キャビティ２９内に存在する溶融樹脂と本体部キャビテイ内に存在する溶融樹脂とに連通する箇所に存在する溶融樹脂の内面の温度が軟化点以下の温度となることにより定められる。
【００８５】
次に、図２４（ｃ）に示すように、中空部２２内のガスの圧力ははるかに外気圧よりも高いので、成形用金型内で冷却固化した成形品２０´の中空部２２内に溜ったガスをガスノズル３２から抜き取る（図２５のＳ６、Ｓ７参照）。媒体注入装置４０Ｄはそのガスの除去装置としても機能する。
【００８６】
そして、成形用金型から成形品２０´を取り外す（図２５のＳ８参照）。
【００８７】
次に、図２３（ｄ）に示すように、成形品２０´の不要部分を切断して、図２４（ｅ）に示す長軸部材２０を仕上げる。
【００８８】
【実施例７】
図２９、図３０、図３１は本発明に係わる長軸部材の成形装置及び成形方法の他の実施例を示している。
【００８９】
この実施例では、固定金型２６に余分樹脂受入キャビティ３４の内壁に開口する中空形成媒体流出部（穴、又はパイプ）４０Ｅが設けられている。固定金型２６に中空形成媒体流出部４０Ｅを設けたわけは、その構成が簡単だからである。
【００９０】
この中空形成媒体流出部４０Ｅはその先端４０Ｇが余分樹脂受入キャビティ３４の中空３４´内に突出する構成としても良い。中空形成媒体流出部４０Ｅの途中には開閉バルブ（流出部開閉制御手段）４０Ｆが設けられている。この開閉バルブ４０ＦはＣＰＵによって制御され、中空３４´が所望の大きさとなるように、ガスが中空形成媒体流出部４０Ｅから流出するのを一定時間禁止するため、開閉バルブ４０Ｆが閉じられる。中空形成媒体流出部４０Ｅの先端４０Ｇが余分樹脂受入キャビティ３４の内壁面と面一の場合には、ＣＰＵはガス圧力によりガスが溶融樹脂４を突き破って中空形成媒体流出部４０Ｅから抜けでない程度以上に硬化した時に開閉バルブ４０Ｆを開成するようにしても良い。
【００９１】
この実施例では、ガスの注入方向と直交する方向からガスを流出させる構成としているが、余分樹脂受入キャビティ３４のガスの注入方向最奥部の内壁面４０Ｈに開口する中空形成媒体流出部４０Ｅを設け、成形品キャビティ２８、２９、３０の内表面に溶融樹脂が行き渡り、所望の形状の成形品２０´が成形され、溶融樹脂の内表面が所望の硬化状態となったとき、ガス注入／ガス抜き手段４０Ｄにより、中空部２２内のガスの圧力を高め、余分樹脂受入キャビテイ３４内に充填された溶融樹脂を突き破ってガスを中空形成媒体流出部４０Ｅから流出させても良い。この場合、ガス注入／ガス抜き手段４０Ｄはガス圧力可変手段として機能する。
【００９２】
この実施例による成形方法は、図３１（ａ）に示すように、開閉バルブ４０ＦをＣＰＵにより開いた状態で溶融樹脂４を成形品キャビテイに注入するのが好ましいが、開閉バルブ４０Ｆを閉じた状態で溶融樹脂４を注入してもよい。
【００９３】
次に、図３１（ｂ）に示すように、ＣＰＵにより開閉バルブ４０Ｆを閉じ、加圧ガスを成形品キャビティ内の溶融樹脂に注入する。開閉バルブ４０Ｆにより中空形成媒体流出部４０Ｅが閉じられているので、中空形成媒体流出部４０Ｅからガスが流出するのが防止され、所望の形状の成形品が形成される。次に、所定時間経過後に、図３１（ｃ）に示すように、ＣＰＵにより開閉バルブ４０Ｆを開く。これにより、中空形成媒体流出部４０Ｅからガスが流出する。残余の工程（図３１（ｄ）、図３１（ｅ））は先に説明した工程と同じなので、その説明は省略する。
【００９４】
【発明の効果】
本発明に係る長軸部材は、中心軸に対して対称形状とされているので、成形の際に、曲がり変形が生じにくく、しかも、軽くて、外観上の見栄えも良好であるという効果を奏する。
【００９５】
特に、長軸部材の軸部に貫通穴を有するインサート部材を設け、回転動力を受けるためのインサート部材の貫通穴を構成する内周壁が、本体部を構成する合成樹脂材料に覆われ、この合成樹脂材料がその内周壁に付着するので、インサート部材をその軸方向から引っ張ったときの引き抜き強度が向上する。
【００９６】
インサート部材の貫通穴の断面形状を円錐形状（テーパ状）としたものにあっては、溶融状態の合成樹脂材料の成形用キャビティへの注入、ガスの溶融状態の合成樹脂材料への注入がスームズに進行するため、成形不良品の発生の低減を図ることができる。
【００９７】
本発明に係わる長軸部材の成形用金型によれば、成形品キャビティに注入された余分の樹脂を受け入れるための余分樹脂受入キャビティを形成したので、中空率の変動を吸収でき、肉厚の均一なかつ変形による曲がりの少ない長軸部材を成形できる。
【図面の簡単な説明】
【図１】本発明に係わる長軸部材の縦断面図である。
【図２】図１に示す長軸部材の成形用金型の部分断面図である。
【図３】図２に示す長軸部材の成形用金型により成形された成形品の縦断面図である。
【図４】本発明に係わる長軸部材の縦断面図で、一方の軸部がインサート部材からなる長軸部材を示している。
【図５】本発明に係わる長軸部材の縦断面図で、他方の軸部がインサート部材からなる長軸部材を示している。
【図６】本発明に係わる長軸部材の縦断面図で、両端の軸部がインサート部材からなる長軸部材を示している。
【図７】図５に示す長軸部材の成形用金型の部分断面図で、成形品キャビティに溶融状態の合成樹脂材料を注入した状態を示している。
【図８】図７に示す溶融状態の合成樹脂材料に加圧ガスを注入して溶融状態の合成樹脂材料を膨らませた状態を示している。
【図９】図８に示す成形用金型の余分樹脂受入キャビティ近傍の部分拡大断面図である。
【図１０】図７に示す長軸部材の成形用金型により成形された成形品を示す縦断面図である。
【図１１】両端の軸部がインサート部材からなる長軸部材の成形工程の一例を示す縦断面図である。
【図１２】本発明に係わる長軸部材の断面図で、両端の軸部がテーパ形状の貫通穴を有するインサート部材からなる長軸部材を示している。
【図１３】図１２に示す長軸部材の成形に使用する成形用金型の部分縦断面図である。
【図１４】図１２に示す長軸部材の成形用金型の部分断面図で、成形品キャビティに溶融状態の合成樹脂材料を注入した状態を示している。
【図１５】図１４に示す溶融状態の合成樹脂材料に加圧ガスを注入して溶融状態の合成樹脂材料を膨らませた状態を示している。
【図１６】本発明に係わる長軸部材の他の実施例を示し、長軸部材の周回り方向に回転非対称の突起が形成され、一部を肉抜きした長軸部材の縦断面図である。
【図１７】図１６の矢印Ｘ−Ｘ線に沿う断面図である。
【図１８】図１６に示す長軸部材の全体形状を示す詳細斜視図である。
【図１９】長軸部材の周回り方向に回転非対称の突起が形成された長軸部材の縦断面図で、肉抜きが設けられていない長軸部材を示している。
【図２０】図１９の矢印Ｙ−Ｙ線に沿う断面図である。
【図２１】本発明に係わる長軸部材の成形に使用する成形装置の概略構成を示す説明図である。
【図２２】図２１に示す成形用金型の部分拡大図であって、水冷用通路の説明図である。
【図２３】ＣＰＵと各制御手段との関係を示すブロック図である。
【図２４】本発明に係わる長軸部材の成形方法の一例を示す説明図であって、
（ａ）は成形用金型の成形品キャビティに溶融状態の合成樹脂材料を注入した状態を示し、
（ｂ）はその溶融状態の合成樹脂材料に加圧ガスを注入して所定時間保圧して冷却固化した状態を示し、
（ｃ）はその冷却固化により形成された成形品の中空部に存在する加圧ガスのガス抜きを行う状態を示し、
（ｄ）は成形用金型から取り出された成形品の断面図を示し、
（ｅ）はその成形品の不要部分を切断することにより形成された長軸部材を示している。
【図２５】長軸部材の成形方法の工程を示すフローチャートである。
【図２６】成形用金型のガスノズル近傍の拡大図を示し、
（ａ）は長軸部材の成形に使用する合成樹脂材料の粘度が高い場合のガス流路を示し、
（ｂ）長軸部材の成形に使用する合成樹脂材料の粘度が低い場合のガス流路を示している。
【図２７】ガス保圧時間と長軸部材の寸法精度との関係を説明する説明図であって、
（ａ）はガス保圧時間と長軸部材の寸法精度との関係を示す特性曲線図、
（ｂ）はガスノズル近傍の成形用金型の部分拡大図で、ガス保圧時間が短い場合の不具合を説明するための説明図である。
【図２８】成形機本体側の溶融状態の合成樹脂材料に加える背圧と加圧ガスの保圧圧力との関係を説明するための成形用金型のガスノズル近傍の拡大図であって、 （ａ）は背圧が加圧ガスの保圧圧力よりも高いことにより、樹脂注入部が塞がれている状態を示し、
（ｂ）は背圧が加圧ガスの保圧圧力よりも低いことにより樹脂注入部が塞がれていない状態が示されている。
【図２９】 本発明に係わる長軸部材の成形装置の他の実施例を示し、
本発明に係わる長軸部材の成形に使用する成形装置の概略構成を示す説明図である。
【図３０】本発明に係わる長軸部材の成形装置の他の実施例を示し、ＣＰＵと各制御手段との関係を示すブロック図である。
【図３１】本発明に係わる長軸部材の成形方法の他の例を示す説明図であって、
（ａ）は成形用金型の成形品キャビティに溶融状態の合成樹脂材料を注入した状態を示し、
（ｂ）はその溶融状態の合成樹脂材料に加圧ガスを注入して所定時間保圧して冷却固化した状態を示し、
（ｃ）はその冷却固化により形成された成形品の中空部に存在する加圧ガスのガスを流出させる状態を示し、
（ｄ）は成形用金型から取り出された成形品の断面図を示し、
（ｅ）はその成形品の不要部分を切断することにより形成された長軸部材を示している。
【図３２】従来の長軸部材成形用金型を用いて長軸部材を成形する工程を示す部分断面図である。
【図３３】従来の長軸部材成形用金型により成形された長軸部材の一例を示す断面図である。
【図３４】従来の長軸部材成形用金型を用いて、一端部にインサート部材が挿入された長軸部材を成形する工程を示す部分断面図である。
【図３５】従来の長軸部材成形用金型を用いて、両端部にインサート部材が挿入された長軸部材を成形する工程を示す断面図である。
【符号の説明】
４…溶融状態の合成樹脂材料
２０…長軸部材
２１…本体部
２２…中空穴
２３…軸部
２３´…金属製シャフト
２４…貫通穴
２８…本体部キャビティ
３２…ガスノズル
３４…余分樹脂受入キャビティ
Ｏ１…回転中心軸
Ｏ２…キャビティ中心軸[0001]
BACKGROUND OF THE INVENTION
The present invention includes a hollow portion formed of a synthetic resin material and extending substantially in the direction in which the central axis extends, substantially concentric with the central axis, and hollow portions at both ends in the extending direction of the hollow portion. The present invention relates to a long shaft member in which a through hole communicating with the outside is formed, and the through hole is substantially concentric with the central axis. More specifically, a small-diameter shaft portion is formed at both ends of a main body portion that has a hollow portion that is substantially concentric with the central shaft and extends in the direction in which the central shaft extends, and that penetrates the hollow portion to the outside. The present invention relates to a long shaft member in which a hole is formed and the through hole is substantially concentric with a central axis, and a molding die for the long shaft member. In particular, the present invention relates to a molding die suitable for molding a long shaft member in which a screw for conveying toner or the like is formed on the outer periphery of a main body.
[0002]
[Prior art]
When the long shaft member is cut from a round bar made of synthetic resin, the cost of the synthetic resin material used for manufacturing the long shaft member increases, and the weight of the long shaft member increases. Further, in the long shaft member used for transporting toner or the like, a plurality of spiral projections constituting a toner transport screw or the like are provided on the outer periphery of the main body portion at intervals, and both end portions in the axial direction of the main body portion are provided. Since it is necessary to provide a shaft portion, the shape of the article is complicated. When such a long shaft member is cut from a round bar made of synthetic resin, the shape of the article is complicated, so that the number of processing steps is increased and the product cost is increased accordingly.
[0003]
Therefore, a technique for integrally molding this type of long shaft member as a whole is known (see Japanese Patent Application Laid-Open No. 5-208460). In this technique (gas injection method), as shown in FIG. 32, a gate 2 for supplying a synthetic resin material in a molten state is provided almost on the extension line of the central axis O0 of the molded product cavity 1 of the molding die. A gas supply pipe (gas supply nozzle) 3 communicates with the gate 2 from a direction substantially perpendicular to 2.
[0004]
In this technique, a predetermined amount of the molten synthetic resin injected into the molded product cavity 1 is measured, and after the molten synthetic resin material 4 is supplied from the gate 2, the molten synthetic resin material is supplied from the gas supply pipe 3. 4 is injected with a pressurized gas. Then, the synthetic resin material 4 in a molten state is pressed and spread over the entire inner surface of the molding die by the pressure of the pressurized gas. As a result, a hollow long-axis member having the same outer shape as the inner shape of the molding die is formed.
[0005]
That is, as shown in FIG. 33, a main body portion 6 having a hollow portion 5 extending in the direction in which the central axis O1 extends and a shaft portion 7 having a smaller diameter than the main body portion 6 are provided at both ends of the main body portion 6. A long shaft member 8 is formed.
[0006]
[Problems to be solved by the invention]
However, the long shaft member 8 formed by this kind of technique is such that the pressurized gas supplied from the gas supply pipe 3 is bent at a substantially right angle and flows into the molded product cavity 1. 8 is likely to bend due to uneven thickness. Moreover, since the through-hole 9 which connects the hollow part 5 to the exterior generate | occur | produces in the outer peripheral surface of one axial part 7 among a pair of axial parts 7 based on supply of pressurized gas, it is unpreferable on an external appearance.
[0007]
In addition, a metal shaft may be used for the shaft portion 7 of the long shaft member 8 to receive rotational power. In the case of molding of the long shaft member 8 provided with the metal shaft 7 at one end, for example, as shown in FIG. 34, the metal shaft 7 is inserted on the side far from the gate 2 of the molded product cavity 1, After injecting the molten synthetic resin material 4 from the gate 2 shown in FIG. 32, pressurized gas is supplied from the gas supply pipe 3. However, the amount of molten resin actually measured for each molding cycle varies.
[0008]
The hollowness fluctuates based on this measurement variation. That is, molten resin is metered into the mold for molding so that the hollow ratio is about 30% of the volume of the molded product, and 70% of the cavity volume is injected. Therefore, when the amount of the molten resin is large, a pool portion 10 of the molten synthetic resin material 4 is generated in the vicinity of the metal shaft 7 far from the gate 2 of the molded product cavity 1, and the pool portion 10 is in a molten state. There is a problem that the synthetic resin material is hard to solidify, the molding cycle time is prolonged, and the product cost is increased. Further, when the molten synthetic resin material in the pool portion 10 is solidified, the shrinkage amount of the pool portion 10 is large, so that the molded product is deformed and the dimensional accuracy is deteriorated. Moreover, when the synthetic resin material in the molten state of the reservoir portion 10 is cured, the portion of the completed long shaft member 8 becomes a thick portion, which is not preferable.
[0009]
On the other hand, when the amount of the molten resin is small, the thickness in the vicinity of the metal shaft 7 far from the gate 2 becomes thin.
[0010]
When the metal shaft 7 is insert-molded at both ends of the long shaft member 8, the gate 2 and the gas supply pipe 3 must be provided in a direction orthogonal to the central axis O0 as shown in FIG. . Also in this case, since the pressurized gas supplied from the gas supply pipe 3 is bent at a substantially right angle and flows into the molded product cavity 1, the molded product is deformed due to uneven thickness. Further, since the reservoir 10 is generated in the vicinity of the metal shaft 7 on the side far from the gate 2, there is a similar problem.
[0011]
The present invention has been made in view of the above circumstances, and is a long shaft member that can be manufactured by integral molding, has a good appearance, is inexpensive, light in weight, and has little bending deformation, and the long shaft member An object of the present invention is to provide a molding die for use in molding of the above.
[0012]
[Means for Solving the Problems]
The long shaft member according to claim 1, wherein the main body portion formed of a synthetic resin material has a hollow portion that is substantially concentric with the central axis and extends long in a direction in which the central axis extends, and both end portions of the main body portion. First and second shaft portions having a diameter smaller than that of the main body portion are formed, and through holes are formed in the respective shaft portions to communicate the hollow portions to the outside. The through holes are substantially concentric with the central shaft. The shaft portion is formed by a metal insert member inserted into at least one end of the main body portion, the through hole is formed in the insert member, and the insert member constitutes the through hole. The peripheral wall is covered with a synthetic resin material forming the main body.
In the long shaft member according to claim 2, the diameter of the through hole continuously increases from the end surface exposed to the outside of the insert member to the end surface embedded in the main body. It is characterized by.
The long-axis member according to claim 3 is characterized in that a plurality of spiral projections are formed on the outer peripheral surface of the main body along the longitudinal direction at intervals.
The long axis member according to claim 4 is provided with a longitudinal projection forming region in which a plurality of spiral projections are formed at intervals along the longitudinal direction on the outer peripheral surface of the main body. The longitudinal protrusion forming region has a protrusion forming portion within a predetermined angular range in the circumferential direction of the main body portion, and a protrusion non-forming portion outside the predetermined angular range, and a cross-sectional thickness of the protrusion non-forming portion. An outer peripheral surface lower than the outer peripheral surface of the protrusion forming portion is formed in the protrusion non-forming portion so that the cross-sectional thickness of the protrusion forming portion is substantially the same.
The molding die for a long shaft member according to claim 5 has a hollow portion in which a main body portion formed of a synthetic resin material is substantially concentric with the central axis and extends long in a direction in which the central axis extends, First and second shaft portions having a diameter smaller than that of the main body portion are formed at both ends of the main body portion, and through holes are formed in the respective shaft portions so as to communicate the hollow portion to the outside. It is substantially concentric with the shaft, the shaft portion is formed by a metal insert member inserted into at least one end portion of the main body portion, the through hole is formed in the insert member, and the insert member An inner peripheral wall constituting the hole is covered with a synthetic resin material forming the main body, and has a cavity central axis corresponding to the central axis of the main body, and forms the main body Formed on the cavity and both ends of the body First and second shaft cavities for forming the formed shaft portion, a medium injection portion for injecting a hollow forming medium for forming the hollow portion through the first shaft portion cavity, and the medium injection portion A resin injecting portion that is provided on the cavity side and injects a molten resin, and out of the molten resin filled in the cavity, excess resin that becomes extra in the cavity due to the injection of the hollow forming medium is added to the second shaft portion. An excess resin receiving cavity that is received through the cavity, a hollow forming medium outflow portion that communicates the extra resin receiving cavity to the outside, and an open / close valve that opens and closes the hollow forming medium outflow portion.
The molding die for a long shaft member according to claim 6 is characterized in that the resin injecting portion is arranged so that molten resin is injected from a direction intersecting with a direction in which the hollow medium is injected. And
The molding die for a long shaft member according to claim 7 is characterized in that at least one of the first and second shaft portion cavities is an installation portion of an insert member having a through hole.
The molding die for a long shaft member according to claim 8 has a hollow portion in which a main body portion formed of a synthetic resin material is substantially concentric with the central axis and extends long in a direction in which the central axis extends, First and second shaft portions having a diameter smaller than that of the main body portion are formed at both ends of the main body portion, and through holes are formed in the respective shaft portions so as to communicate the hollow portion to the outside. The shaft portion is formed of a metal insert member that is substantially concentric with the shaft and inserted into at least one end of the main body portion, and the through hole is formed in the insert member. A body part cavity having a cavity central axis corresponding to the central axis of the main body part, the inner peripheral wall forming the main body part being covered with a synthetic resin material forming the main body part And formed at both ends of the main body The first for forming the shaft portion, and a second shaft portion cavity, for forming the hollow portion to the body portion cavity through the first shaft portion cavity A gas injection part for injecting a gas; a resin injection part for injecting a molten resin from a direction intersecting the gas injection direction provided on the cavity side of the gas injection part; and a molten resin filled in the cavity An extra resin receiving cavity communicated with the main body cavity through the second shaft cavity to receive extra resin that is extraneous in the cavity due to the gas injection, and the extra resin receiving cavity And a hollow forming medium outflow portion communicating with the opening and an open / close valve for opening and closing the hollow forming medium outflow portion.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
The long shaft member and its molding die according to the present invention will be described below together with a molding apparatus and a molding method for the long shaft member.
[0027]
[Example 1]
In FIG. 1, 20 is a long shaft member. The long shaft member 20 has a cylindrical main body 21 formed of a synthetic resin material. The main body 21 has a hollow portion 22 which is substantially concentric with the central axis O1 and extends long in the direction in which the central axis O1 extends. Cylindrical first and second shaft portions 23 having a smaller diameter than the main body portion 21 are formed at both ends of the main body portion 21. Each shaft portion 23 is formed with a through hole 24 that communicates the hollow portion 22 to the outside. The through hole 24 is substantially concentric with the central axis O1. On the outer periphery of the main body 21, a plurality of spiral protrusions 25 constituting a conveying screw are formed at intervals. The through hole 24 is formed by injecting a gas as a hollow forming medium by a gas injection method from a direction parallel to the central axis O1 after injecting a molten synthetic resin material into a molding die to be described later. As the hollow forming medium, a liquid can be used in addition to a gas (gas).
[0028]
FIG. 2 shows a molding die for the long shaft member 20 shown in FIG. 1. In FIG. 2, 26 is a fixed die and 27 is a movable die. A main body cavity (molded product cavity) 28 corresponding to the main body 21 is formed between the fixed mold 26 and the movable mold 27. The main body cavity 28 has a cavity central axis O 2 corresponding to the central axis O 1 of the main body 21. At both ends of the main body cavity 28, first and second shaft cavities (molded product cavities) 29 and 30 corresponding to the first and second shaft portions made of a synthetic resin material are formed. At one end of the main body cavity 28, a gas nozzle (medium injection part) 32 for injecting gas from a gas pressure source into the main body cavity 28 is provided substantially concentrically with the central axis O2. Further, a resin injection part 31 for injecting a molten synthetic resin material into the main body cavity 28 is formed between the gas nozzle 32 and the cavity 29. The fixed mold 26 is formed with an injection passage 33 for injecting a molten synthetic resin material into the resin injection portion 31 from a direction intersecting (orthogonal to) the gas injection direction from the gas nozzle 32. An extra resin receiving cavity 34 is formed at the other end of the main body cavity 28 to receive extra molten synthetic resin material injected from the resin injection portion 31. The excess resin receiving cavity 34 communicates with the main body cavity 28 with the connection passage 35 and the second shaft cavity 30 interposed therebetween. The excess resin receiving cavity 34 is substantially concentric with the central axis O1. The main body cavity 28 is formed with a recess 36 for forming the protrusion 25 on the inner peripheral wall thereof.
[0029]
In this molding die, a molten synthetic resin material is injected into the resin injection portion 31 through the injection passage 33, and gas is supplied to the main body cavity 28 from the direction of the central axis O2. The molten synthetic resin material 4 is moved toward the excess resin receiving cavity 34 while being pressed against the entire inner surface of the main body cavity 28 by the pressure of the pressurized gas. The extra molten synthetic resin material that is not used as the long shaft member 20 is pushed out from the central axis direction toward the extra resin receiving cavity 34 by the pressure of the gas. The material 4 is distributed almost uniformly. Thereby, as shown in FIG. 3, a hollow molded product 20 ′ having the same outer shape as the inner shape of the molding die is formed.
[0030]
This molded product 20 ′ has a meat part 31 ′ corresponding to the resin injection part 31, a meat part 35 ′ corresponding to the connection part 35, and a surplus part 34 ′ corresponding to the extra resin receiving cavity 34. The long shaft member 20 is completed by cutting the molded product 20 ′ at arrows A and A.
[0031]
For details of the method of forming the long shaft member 20, refer to the forming method of the embodiment described later.
[0032]
[Example 2]
4 to 11 show a second embodiment of the long shaft member 20 according to the present invention. 4 to 11, at least one of the shaft portions 23 of the long shaft member 20 is a metal shaft 23 ′ for receiving rotational power.
[0033]
FIG. 4 shows a long shaft member 20 formed by inserting a metal shaft 23 ′ as an insert member into an end portion (one end portion) of the main body cavity 28 near the gas nozzle 32. FIG. 5 shows the long shaft member 20 formed by inserting a metal shaft 23 ′ as an insert member into the end portion (the other end portion) of the main body portion cavity 28 near the excess resin receiving cavity 34. . FIG. 6 shows the long shaft member 20 formed by inserting a metal shaft 23 ′ as an insert member at both ends of the main body cavity 28. The metal shaft 23 'is cylindrical and has a through hole 24 in the axial direction. Here, the metal shaft 23 ′ is used as the insert member, but a material different from the synthetic resin material constituting the main body 21 may be used as the insert member, and the insert member is not limited to the metal.
[0034]
The same molding die as shown in FIG. 2 can be used, and in this case, a metal shaft 23 ′ is installed in at least one of the first and second shaft cavities 29 and 30.
[0035]
That is, a long shaft member 20 in which a metal shaft 23 ′ is inserted into one end of the main body 21 and the second shaft 23 is formed of a synthetic resin material at the other end of the main body 21 (see FIG. 4). ), The insert member 23 ′ is installed in the first shaft cavity 29 existing at one end of the body cavity 28 for molding the body 21. Further, the gas from the gas pressure source is injected into the main body cavity 28 through the through hole 24 of the metal shaft 23 '.
[0036]
A long shaft member 20 (see FIG. 5) in which a metal shaft 23 ′ is inserted into the other end portion of the main body portion 21 and a first shaft portion 23 is formed of a synthetic resin material at one end portion of the main body portion 21. In this case, the insert member 23 ′ is installed in the second shaft cavity 30 existing at the other end of the main body cavity 28 for molding the main body 21. Further, the extra resin receiving cavity 34 communicates with the main body cavity 28 through the through hole 24 of the metal shaft 23 ′.
[0037]
In the case of the long shaft member 20 in which the metal shaft 23 ′ is inserted at both ends of the main body 21 (see FIG. 6), the insert member 23 ′ is inserted into both the first and second shaft cavities 29 and 30. Is installed. The gas nozzle 32 communicates with the main body cavity 28 through the through hole 24 of the metal shaft 23 ′ installed in the first shaft cavity 29, and the extra resin receiving cavity 34 is an insert installed in the second shaft cavity 30. It communicates with the main body cavity 28 through the through hole 24 of the member 23 '. The through hole 24 of the metal shaft 23 'is installed substantially concentrically with the central axis O2. The diameter of the through hole 24 is the same from the end surface exposed from the main body 21 of the metal shaft 23 ′ to the end surface embedded in the main body 21.
[0038]
An outline of a method of forming the long shaft member 20 shown in FIGS. 4 to 6 will be described with reference to the drawings shown in FIGS.
[0039]
7 to 10 show a method of forming the long shaft member 20 (see FIG. 5) in which a metal shaft 23 ′ is provided at the other end of the main body 21.
[0040]
First, as shown in FIG. 7, the molten synthetic resin material 4 is injected into the resin injection portion 31 from the resin injection passage 33. Then, the synthetic resin material 4 in a molten state is injected from the resin injection part 31 through the first shaft part cavity 29 to one end of the main body part cavity 28. The injection of the molten synthetic resin material 4 is stopped in a state where a predetermined amount of the molten synthetic resin material 4 is injected into the main body cavity 28. That is, injection of the synthetic resin material 4 in a molten state is stopped by a short shot, or immediately before the stop, pressurized gas is injected from the gas nozzle 32 into the resin injection portion 31 as shown in FIG.
[0041]
The molten synthetic resin material 4 is deprived of heat from the contact surface of the molding die and solidifies by cooling. However, the progress of cooling and solidification in the central portion of the synthetic resin material 4 in the molten state is slower than the contact surface. Therefore, the synthetic resin material 4 in the molten state in the central part, which is slowly cooled and solidified, is moved while being swollen toward the other end of the main body cavity 28 by the pressure of the pressurized gas. Due to the pressure of the pressurized gas, the synthetic resin material 4 in the molten state passes through the other end of the main body cavity 28, the through hole 24 of the metal shaft 23 ', and the connection passage 35 as shown in FIG. , Moved toward the excess resin receiving cavity 34. Further, the molten synthetic resin material 4 is pressed against the inner surface of the main body cavity 28 by the pressure of the pressurized gas, and the hollow portion 22 is formed therein. The fluctuation of the hollow ratio is absorbed by the extra resin receiving cavity 34.
[0042]
Since the synthetic resin material 4 in the molten state is guided to the excess resin receiving cavity 34 through the through hole 24 of the metal shaft 23 ′, the inner peripheral wall constituting the through hole 24 of the metal shaft 23 ′ is integrated with the main body 21. It will be covered with the resin material 4. Therefore, the contact area between the metal shaft 23 ′ and the main body 21 existing at the other end of the main body 21 is increased, and the tensile strength in the axial direction is increased.
[0043]
As shown in FIG. 10, the molded product 20 ′ taken out from the molding die is integrally formed with the meat portions 31 ′ and 35 ′ and the surplus portion 34 ′. The long shaft member 20 shown in FIG.
[0044]
FIG. 11 shows an explanatory view in the case where the long shaft member 20 (see FIG. 6) is formed by inserting the metal shaft 23 ′ at both ends of the main body cavity 28. When the long shaft member 20 shown in FIG. 6 is molded, a predetermined amount of a synthetic resin material in a molten state is passed through the through hole 24 of the metal shaft 23 ′ installed in the first shaft cavity 29. 28 is injected. The gas is injected into the main body cavity 28 through the through hole 24 of the metal shaft 23 ′ immediately before or after the injection of the molten synthetic resin material is stopped. The inner peripheral wall constituting the through hole 24 of the metal shaft 23 ′ installed in the first shaft portion cavity 29 is covered with the synthetic resin material 4 integral with the main body portion 21. Therefore, the contact area between the metal shaft 23 ′ present at one end of the main body 21 and the main body 21 also increases, and the tensile strength in the axial direction increases.
[0045]
[Example 3]
12 to 15 show a third embodiment of the long shaft member 20 according to the present invention. 12 to 15, both end portions of the shaft portion 23 of the long shaft member 20 are made of a metal shaft 23 ′ for receiving rotational power, and the diameter of the through hole 24 of the metal shaft 23 ′ is made of a metal shaft. 23 'is continuously increased from the end surface exposed to the outside to the end surface embedded in the main body 21. That is, the inner peripheral wall constituting the through hole 24 of the metal shaft 23 'is conical (tapered).
[0046]
In order to form the long shaft member 20, as shown in FIG. 13, a metal shaft 23 ′ having a tapered through hole 24 is set in the cavities 29, 30. Next, as shown in FIG. 14, the molten synthetic resin material 4 is injected into the main body cavity 28 through the tapered through hole 24. Since the cross-sectional area of the through hole 24 increases toward the main body cavity 28, the pressure loss can be reduced as compared with the case where the metal shaft 23 'having the shape shown in FIGS. A predetermined amount of the molten synthetic resin material 4 can be reliably injected into the main body cavity 28.
[0047]
Next, in FIG. 15, gas is injected from the direction of the central axis O <b> 2, and the synthetic resin material 4 in a molten state is spread all over the corners of the main body cavity 28. Also during the gas injection, the cross-sectional area of the through hole 24 increases toward the main body cavity 28, so that the pressure loss can be reduced, and the gas can be supplied without almost losing the gas pressure. It can be injected into the body cavity 28. That is, since the gas is injected while spreading toward the main body cavity 28, the gas smoothly flows into the main body cavity 28.
[0048]
Further, in the metal shaft 23 ′ set in the cavity 30 existing at the other end of the main body cavity 28, the cross-sectional area of the through hole 24 increases from the main body cavity 28 side toward the excess resin receiving cavity 34. Therefore, the pressure when the molten synthetic resin material 4 is pushed into the excess resin receiving cavity 34 increases, whereby the excessive molten synthetic resin material smoothly flows into the excess resin receiving cavity 34. Moved to.
[0049]
In this embodiment, the metal shaft 23 ′ having the tapered through hole 24 is provided on both sides of the main body 21 as the shaft portion, but either of the metal shafts 23 ′ having the tapered through hole 24 is provided. You may make it provide only in one and the other axial part may be comprised from a synthetic resin material.
[0050]
[Example 4]
19 and 20 show the long-axis member 20 in which the spiral protrusion 25 formed on the outer periphery of the main body 21 along the longitudinal direction thereof is asymmetric in the circumferential direction with respect to the central axis O1. In the case of this long shaft member 20, as shown in FIG. 19, the central axis that is the center of the contour shape at the center O 1 ′ of the hollow portion 22 and the main body portion 21 where the plurality of protrusions 25 are formed. As shown in FIG. 20, the protruding portion missing portion 21 ′ of the main body portion 21 tends to be thick. This is because the synthetic resin material 4 in the molten state is large on the projecting portion forming side, and thus the molten synthetic resin material 4 existing on the projecting portion forming side is hardly cooled and cured. For this reason, the main body portion 21 becomes a bow, and the long shaft member 20 may be bent.
[0051]
Therefore, as shown in FIGS. 16, 17, and 18, the lightening portion extends from one side to the other side of the longitudinal direction protrusion formation region 21 </ b> A on the outer peripheral surface of the main body portion 21 on which the plurality of protrusion portions 25 are formed. 36 was formed. Thereby, the center of the contour shape of the main body portion 21 is the central axis so that the center O1 ′ of the hollow portion 22 and the center of the contour shape of the main body portion 21 where the plurality of protrusions 25 are formed coincide with each other. Shifted from O1.
[0052]
As described above, when the lightening portion 36 is formed from one to the other of the main body portion 21 in which a plurality of asymmetric protrusions 25 are formed, a plurality of asymmetric protrusions 25 are formed. Since the thickness of the main body portion 21 is uniform from one side to the other side, the straight long shaft member 20 can be formed.
[0053]
That is, in the longitudinal projection forming area 21A, a projection is formed at a predetermined interval in the longitudinal direction, the projection forming portion 21B exists within a predetermined angular range in the circumferential direction, and a protruding portion missing portion 21 ′ is located outside the predetermined angular range. There is a non-projection forming part. Therefore, if the thinned portion 36 having an outer peripheral surface lower than the outer peripheral surface of the base of the protrusion forming portion 21B is formed in the protrusion non-forming portion of the longitudinal protrusion forming region 21A, the cross-sectional thickness of the protrusion non-forming portion is The cross-sectional thickness of the protrusion forming portion is substantially the same.
[0054]
[Example 5]
FIG. 21 shows a schematic diagram of the overall configuration of the molding apparatus for the long shaft member 20 according to the present invention.
[0055]
In FIG. 21, reference numeral 40 denotes an injection molding machine main body (resin filling device or resin filling means). The injection molding machine main body 40 is provided with a hopper 41, and solid pellets 42 are stored in the hopper 41. The pellets 42 are supplied in predetermined units to the pressure melting chamber 42b of the cylinder 42a, and are made into a synthetic resin material 4 'in a molten state by the screw rod 42c. The molten synthetic resin material 4 ′ is guided to the resin injection portion 31 through the resin injection passages 43 and 33 of the fixed mold 26. A water cooling passage for controlling the temperature in the vicinity of the gas nozzle, as shown in FIG. 22, is provided in the portions of the molding dies 26 and 27 in the vicinity of the gas nozzle 32 and the portion of the molding die in the vicinity of the main body cavity 28. A (temperature adjusting member) 44 and a water cooling passage (temperature adjusting member) 45 for adjusting the temperature of the main body cavity are formed. The temperature of the cooling water supplied to the water cooling passage 44 is 50 degrees, and the temperature of the cooling water supplied to the water cooling passage 45 is 10 degrees. Thereby, the cooling temperature of the molding dies 26 and 27 in the vicinity of the gas nozzle 32 is set to a temperature higher than the cooling temperature of the molding dies in the vicinity of the main body cavity 28. The temperature of the temperature adjusting member is controlled by temperature adjusting means 40B and 40C described later.
[0056]
This is for the reason explained below.
[0057]
The molten synthetic resin material 4 is cooled by contact with the inner peripheral wall of the main body cavity 28. However, gas is supplied to the central portion of the synthetic resin material 4 in a molten state and is not forcibly cooled. For this reason, if the synthetic resin material 4 in a molten state is cooled only depending on the contact with the inner peripheral wall of the main body cavity 28, the cooling time takes longer and the molding cost of the long shaft member 20 becomes higher. Therefore, generally, a molding cycle is shortened by forcibly cooling a molding die using a cooler (chiller).
[0058]
However, if the temperature of the portion of the molding die near the gas nozzle 32 is cooled at the same temperature as the cooling temperature of the portion of the molding die near the main body cavity 28, the molten synthetic resin material 4 is cooled. Even if the resin is cured too much and the pressurized gas is injected, the synthetic resin material 4 in the molten state does not swell and the hollow portion may not be formed in the synthetic resin material 4 in the molten state.
[0059]
Therefore, in order to reduce the curing rate of the molten synthetic resin material 4 in the vicinity of the gas nozzle 32 while shortening the molding cycle of the long shaft member 20, the portions of the molding dies 26 and 27 in the vicinity of the gas nozzle 32 are controlled. The cooling temperature was set to a temperature higher than the cooling temperature of the portion of the molding die near the main body cavity 28.
[0060]
The reason for setting the temperature of the cooling water supplied to the water cooling passage 45 to 10 degrees is that if the mold is cooled at a temperature lower than this, the cooling and solidification of the molten synthetic resin material 4 proceeds too much, This is because, before the molten synthetic resin material 4 reaches the excess resin receiving cavity 34, the movement stops and the long shaft member 20 having a desired shape cannot be obtained.
[0061]
The reason for setting the temperature of the cooling water supplied to the water cooling passage 44 to 50 degrees is that when the mold is cooled at a temperature lower than this, the cooling and solidification of the molten synthetic resin material 4 proceeds too much, This is because even when the pressurized gas is injected, the molten synthetic resin material 4 does not swell and the pressurized gas is not easily injected into the main body cavity 28. On the other hand, if the mold is cooled at a temperature higher than this, the temperature of the mold in the vicinity of the gas nozzle 32 is too high, and the fluidity of the molten synthetic resin material 4 increases. Therefore, when the gas is injected, the synthetic resin material 4 in the molten state may be blown off by the injection of the gas. Accordingly, the temperature of the molten synthetic resin material 4 in the vicinity of the gas nozzle 32 is set to 50 ° C. as a temperature at which the temperature is equal to or higher than the glass transition point and no blow-out occurs due to gas injection.
[0062]
Control of start and end of injection filling for each molding cycle, control of cooling water flow to injection molding machine main body 40, water cooling passages 44 and 45, injection of gas into main body cavity 28, and gas from main body cavity 28 Removal control is performed by the CPU. The CPU performs these controls in conjunction with mold opening and mold clamping of the molding die.
[0063]
That is, as shown in FIG. 23, the CPU, via the input output interface, the injection molding machine main body 40, the molding die driving means 40A, the main body cavity temperature adjusting means 40B, the gas nozzle vicinity temperature adjusting means 40C, the gas The injection and degassing means (medium injection device) 40D is controlled.
[0064]
The temperature adjusting means (temperature control devices) 40B and 40C pass through the molten resin 4 in which at least the hollow forming medium passes through the molten resin filled in the first shaft cavity 29 and is filled in the main body cavity 28. Operate until injected.
[0065]
[Example 6]
Details of the method of forming the long shaft member 20 by this forming apparatus will be described below.
[0066]
In addition, in this Example 6, the case where the long shaft member 20 shown in FIG. 5 is shape | molded is demonstrated. However, the present invention can also be applied to the molding of the long shaft member 20 shown in FIG. 1, FIG. 4, FIG. 6, and FIG.
[0067]
First, as shown in FIG. 24 (a), the metal shaft 23 'is set in a molding die and the die is closed (see step S1 in FIG. 25). Next, the molten synthetic resin material 4 is injected into the main body cavity 28 at a predetermined pressure (see steps S2 and S3 in FIG. 25). That is, the molten synthetic resin material 4 is injected by a short shot.
[0068]
For the synthetic resin material 4, for example, ABS is used. If the viscosity of the synthetic resin material 4 in the molten state is too low, the mass of the synthetic resin material 4 in the molten state is pierced by the pressurized gas, and the pressurized gas leaks into the main body cavity 28 and has a desired shape. The molded product 20 'cannot be obtained. On the other hand, if the viscosity of the synthetic resin material 4 in the molten state is too high, the synthetic resin material 4 in the molten state does not swell smoothly with the pressurized gas, and a desired hollow shaped molded product 20 ′ cannot be obtained. Furthermore, it is necessary to consider the rigidity of the long shaft member 20 'as a finished product. Therefore, here, glass fiber is mixed with ABS resin. The glass fiber content was 30% by weight. The glass fiber has an average fiber length of 3 mm and an average fiber diameter of 13 μm.
[0069]
When an ABS resin having a different viscosity was used to evaluate moldability (international test method standard (abbreviated as ASTM)), the following results were obtained.
[0070]
Here, comparison was made with respect to two types of ABS resins, product names NC411-G30 and NC100-G30 manufactured by Technopolymer. In all cases, the glass fiber content was 30% by weight. The product name NC411-G30 is 12.0 g / min under a melt flow rate of 220 degrees and 98 N, and has a high viscosity. On the other hand, product name NC100-G30 is 40.0 g / min under a melt flow rate of 220 degrees and 98 N, and has a low viscosity.
[0071]
When a molding experiment was performed on these two types of ABS, uneven thickness occurred in the ABS resin having a high viscosity of the synthetic resin material 4. In the ABS resin having a low viscosity of the synthetic resin material 4, uneven thickness did not occur.
[0072]
This is considered to be because, as shown in FIG. 26A, when the viscosity of the synthetic resin material 4 is high, the gas inflow direction is bent with respect to the central axis O2 in the vicinity of the resin injection portion 31. On the other hand, as shown in FIG. 26B, when the viscosity of the synthetic resin material 4 is low, the gas pressure overcomes the viscosity of the synthetic resin material 4, and the gas inflow direction is parallel to the central axis O2. it is conceivable that.
[0073]
The temperature of the molten synthetic resin material 4 is, for example, 240 degrees. The injection amount of the synthetic resin material 4 in the molten state is preferably about 70% of the volume of the main body cavity 28. However, the injection amount of the molten resin injected by the resin filling device and the medium injection device was injected. The total amount of the hollow forming medium injected may be equal to or greater than the sum of the volume of the main body cavity 28 formed in the molding die and the volume of the first and second shaft cavities 29 and 30.
[0074]
Next, as shown in FIG. 24B, gas is injected into the resin injection portion 31 from the direction of the central axis O2 immediately before or after the injection of the molten synthetic resin material 4 is stopped. Then, the molten synthetic resin material 4 is moved toward the excess resin receiving cavity 34 while being inflated, and the molten synthetic resin material 4 is spread over the entire inner surface of the main body cavity 28. By injecting this gas from the direction of the central axis O2, a hollow portion 22 extending in the direction of the central axis O2 is formed. The excess molten synthetic resin material 4 is guided to the excess resin receiving cavity 34, thereby absorbing the variation in the hollow ratio.
[0075]
The gas pressure is 50 to 300 kg / cm.2Can be selected within the range of 110 kg / cm.2Injection was performed at a pressure of. If the gas pressure is too low, a sufficiently hollow molded product 20 ′ cannot be obtained. If the gas pressure is too high, the pressurized gas breaks through the molten synthetic resin material 4 and leaks into the main body cavity 28. Therefore, the molded product 20 ′ having a desired shape cannot be obtained, and is about 110 kg / cm.2It is preferable to apply a predetermined pressure of
[0076]
Then, the gas pressure is maintained for a certain time. As a result, the molten synthetic resin material 4 that has spread over the entire inner surface of the main body cavity 28 is cooled and solidified (see steps S4 and S5 in FIG. 25). Here, the gas pressure holding time was set to 40 seconds by taking into consideration the securing of dimensional accuracy of the long shaft member 20 and the shortening of the molding cycle. At least the surface of the molded product 20 ′ is cooled to the glass transition temperature or lower, and when the molded product 20 ′ is ejected, the molded product 20 ′ is placed in the mold so as not to be deformed due to shrinkage after the molded product is taken out. It is necessary to cool and harden.
[0077]
That is, the relationship shown by the graph in FIG. 27A is obtained between the gas holding time and the dimensional accuracy of the molded product 20 ′. In FIG. 27A, the horizontal axis represents the gas holding time, and the vertical axis represents the dimensional accuracy of the long-axis member 20. Here, as the dimensional accuracy of the long shaft member 20, the rotational runout of the long shaft member 20 is used.
[0078]
That is, using the first and second shaft portions 23 as a reference, the maximum amount of change of the needles when the needle was brought into contact with the outer peripheral surface of the main body portion 21 and the long shaft member 20 was rotated once was measured.
[0079]
In FIG. 27 (a), the symbol Q0 is a characteristic curve showing the relationship between the gas holding time and the dimensional accuracy of the molded product 20 '. Since the resin material 4 is not sufficiently cooled and solidified, when the molded product 20 ′ is taken out from the mold, the molded product 20 ′ is greatly deformed by cooling and solidifying the synthetic resin material 4, and the dimensional accuracy of the molded product 20 ′ is lowered. In addition, as shown in FIG. 27B, a part of the molten synthetic resin material that is not cooled and solidified in the main body cavity 28 in the vicinity of the gas nozzle 32 is exposed to the gas pressure by the wind pressure when the gas is released as described later. The gas nozzle 32 may be clogged.
[0080]
On the other hand, in the region Q2 where the pressure holding time is long, the dimensional accuracy of the long shaft member 20 is improved. However, the biting of the mold due to the shrinkage of the molded product increases, and a mold release failure occurs when the molded product 20 ′ is taken out. Therefore, it may break when the molded product 20 'is taken out.
[0081]
Therefore, the pressure holding time of the gas in the hollow portion 22 is set in consideration of the dimensional accuracy of the long shaft member 20 and the progress of the curing of the molten synthetic resin material.
[0082]
During the pressure holding of the gas, the pellet 42 is weighed on the side of the molding machine main body 40 in order to manufacture the next molded product. At this time, in order to improve the measurement accuracy, back pressure (into the injection passage 33 of the resin injection portion 31 is applied to the synthetic resin material 4 ′ in the molten state stored in the pressure melting chamber 42 b on the molding machine body 40 side by the screw rod 42 c. Weighing while applying pressure (at a pressure at which the molten resin stops). When the back pressure P0 is higher than the gas holding pressure P1, a part of the molten synthetic resin material 4 ′ existing in the injection passage 33 leaks into the resin injection portion 31 as shown in FIG. It will come out and block a part of the through hole 24. Accordingly, the gas holding pressure P1 is set larger than the back pressure P0. Thus, when the gas holding pressure P1 is set to be larger than the back pressure P0, as shown in FIG. 28B, the molten synthetic resin material 4 ′ existing in the injection passage 33 enters the injection passage 33. It can be prevented that the through hole 24 is blocked by being pushed in. This stationary pressure is controlled by a CPU (control device).
[0083]
That is, the injection pressure of the medium injection device 40D is also controlled by the CPU, and this pressure P1 is higher than the stationary pressure P0. The operation of the medium injection device 40D is preferably performed until the inner surface of the molten resin 4 is stabilized.
[0084]
The stability of the inner surface of the molten resin 4 is such that the temperature of the inner surface of the molten resin existing in the portion communicating with the molten resin existing in the first shaft cavity 29 and the molten resin existing in the main body cavity is below the softening point. It is determined by becoming the temperature.
[0085]
Next, as shown in FIG. 24 (c), the pressure of the gas in the hollow portion 22 is much higher than the outside air pressure, so that the inside of the hollow portion 22 of the molded product 20 ′ cooled and solidified in the molding die. The accumulated gas is extracted from the gas nozzle 32 (see S6 and S7 in FIG. 25). The medium injection device 40D also functions as the gas removal device.
[0086]
Then, the molded product 20 ′ is removed from the molding die (see S8 in FIG. 25).
[0087]
Next, as shown in FIG.23 (d), the unnecessary part of molded product 20 'is cut | disconnected and the long shaft member 20 shown in FIG.24 (e) is finished.
[0088]
[Example 7]
29, 30 and 31 show another embodiment of a long shaft member forming apparatus and method according to the present invention.
[0089]
In this embodiment, the fixed mold 26 is provided with a hollow forming medium outflow portion (hole or pipe) 40E that opens in the inner wall of the excess resin receiving cavity 34. The reason why the hollow forming medium outflow portion 40E is provided in the stationary mold 26 is that its configuration is simple.
[0090]
The hollow forming medium outflow portion 40E may have a configuration in which the tip 40G projects into the hollow 34 'of the excess resin receiving cavity 34. An opening / closing valve (outflow portion opening / closing control means) 40F is provided in the middle of the hollow forming medium outflow portion 40E. The on-off valve 40F is controlled by the CPU, and the on-off valve 40F is closed in order to prevent the gas from flowing out of the hollow forming medium outflow part 40E for a certain period of time so that the hollow 34 'has a desired size. When the tip 40G of the hollow forming medium outflow portion 40E is flush with the inner wall surface of the extra resin receiving cavity 34, the CPU does not escape from the hollow forming medium outflow portion 40E by the gas pressure through the molten resin 4. The open / close valve 40F may be opened when cured.
[0091]
In this embodiment, the gas is caused to flow out from the direction perpendicular to the gas injection direction. However, the hollow forming medium outflow portion 40E that opens to the inner wall surface 40H at the innermost portion 40H in the gas injection direction of the excess resin receiving cavity 34 is provided. When the molten resin spreads over the inner surfaces of the molded product cavities 28, 29 and 30 to form a molded product 20 'having a desired shape and the inner surface of the molten resin is in a desired cured state, gas injection / gas The extraction means 40D may increase the pressure of the gas in the hollow portion 22, break through the molten resin filled in the excess resin receiving cavity 34, and allow the gas to flow out from the hollow forming medium outflow portion 40E. In this case, the gas injection / degassing means 40D functions as a gas pressure variable means.
[0092]
In the molding method according to this embodiment, as shown in FIG. 31 (a), it is preferable to inject the molten resin 4 into the molded product cavity with the open / close valve 40F opened by the CPU, but the open / close valve 40F is closed. Alternatively, the molten resin 4 may be injected.
[0093]
Next, as shown in FIG. 31 (b), the CPU closes the open / close valve 40F and injects pressurized gas into the molten resin in the molded product cavity. Since the hollow forming medium outflow portion 40E is closed by the on-off valve 40F, the gas is prevented from flowing out from the hollow forming medium outflow portion 40E, and a molded product having a desired shape is formed. Next, after a predetermined time elapses, as shown in FIG. 31 (c), the CPU opens the on-off valve 40F. Thereby, gas flows out from hollow formation medium outflow part 40E. The remaining steps (FIGS. 31 (d) and 31 (e)) are the same as the steps described above, and a description thereof will be omitted.
[0094]
【The invention's effect】
Since the long shaft member according to the present invention has a symmetrical shape with respect to the central axis, there is an effect that bending deformation hardly occurs during molding, and it is light and has a good appearance. .
[0095]
  Especially, it has a through hole in the shaft part of the long shaft memberInsert members are provided,The inner peripheral wall constituting the through hole of the insert member for receiving rotational power is covered with the synthetic resin material constituting the main body, and this synthetic resin material is applied to the inner peripheral wall.Because it adheresThe pull-out strength when the insert member is pulled from the axial direction is improved.
[0096]
In the case where the cross-sectional shape of the through hole of the insert member is conical (tapered), the injection of the molten synthetic resin material into the molding cavity and the injection of the gas into the molten synthetic resin material is smooth. Therefore, it is possible to reduce the occurrence of defective molding.
[0097]
According to the molding tool for a long shaft member according to the present invention, since the extra resin receiving cavity for receiving the extra resin injected into the molded product cavity is formed, the fluctuation of the hollow ratio can be absorbed, and the wall thickness can be increased. A long shaft member that is uniform and has little bending due to deformation can be formed.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a long shaft member according to the present invention.
2 is a partial cross-sectional view of a long-axis member molding die shown in FIG. 1. FIG.
FIG. 3 is a longitudinal sectional view of a molded product formed by a long die molding tool shown in FIG. 2;
FIG. 4 is a longitudinal sectional view of a long shaft member according to the present invention, and shows a long shaft member in which one shaft portion is an insert member.
FIG. 5 is a longitudinal sectional view of a long shaft member according to the present invention, in which the other shaft portion shows a long shaft member made of an insert member.
FIG. 6 is a longitudinal sectional view of a long shaft member according to the present invention, and shows a long shaft member in which shaft portions at both ends are made of insert members.
FIG. 7 is a partial cross-sectional view of the molding die for the long shaft member shown in FIG. 5, showing a state in which a synthetic resin material in a molten state is injected into the molded product cavity.
8 shows a state in which a pressurized synthetic gas is injected into the molten synthetic resin material shown in FIG. 7 to expand the molten synthetic resin material.
9 is a partially enlarged cross-sectional view of the molding die shown in FIG. 8 in the vicinity of an excess resin receiving cavity.
10 is a longitudinal sectional view showing a molded product formed by the long-axis member forming die shown in FIG.
FIG. 11 is a longitudinal sectional view showing an example of a long-axis member forming process in which shaft portions at both ends are made of insert members.
FIG. 12 is a cross-sectional view of a long shaft member according to the present invention, showing a long shaft member made of an insert member in which both end shaft portions have tapered through holes.
13 is a partial longitudinal sectional view of a molding die used for molding the long shaft member shown in FIG. 12. FIG.
14 is a partial cross-sectional view of the long-axis member molding die shown in FIG. 12, showing a state in which a synthetic resin material in a molten state is injected into a molded product cavity.
15 shows a state in which a pressurized synthetic gas is injected into the molten synthetic resin material shown in FIG. 14 to expand the molten synthetic resin material.
FIG. 16 is a longitudinal sectional view of a long shaft member showing another embodiment of the long shaft member according to the present invention, in which a rotationally asymmetric protrusion is formed in the circumferential direction of the long shaft member, and a part thereof is thinned. .
17 is a cross-sectional view taken along the line XX in FIG.
18 is a detailed perspective view showing the overall shape of the long shaft member shown in FIG. 16. FIG.
FIG. 19 is a longitudinal sectional view of a long shaft member in which a rotationally asymmetric protrusion is formed in a circumferential direction of the long shaft member, and shows the long shaft member that is not provided with a thinning.
20 is a cross-sectional view taken along the line YY of FIG.
FIG. 21 is an explanatory diagram showing a schematic configuration of a molding apparatus used for molding a long shaft member according to the present invention.
22 is a partially enlarged view of the molding die shown in FIG. 21, and is an explanatory view of a water cooling passage. FIG.
FIG. 23 is a block diagram illustrating a relationship between a CPU and each control unit.
FIG. 24 is an explanatory view showing an example of a method for forming a long shaft member according to the present invention,
(A) shows a state in which a synthetic resin material in a molten state is injected into a molded product cavity of a molding die,
(B) shows a state in which a pressurized gas is injected into the molten synthetic resin material and held for a predetermined time to be cooled and solidified,
(C) shows the state of degassing the pressurized gas present in the hollow part of the molded product formed by the cooling and solidification,
(D) shows a cross-sectional view of the molded product taken out from the molding die,
(E) has shown the long-axis member formed by cut | disconnecting the unnecessary part of the molded article.
FIG. 25 is a flowchart showing steps of a method for forming a long shaft member.
FIG. 26 shows an enlarged view of the vicinity of the gas nozzle of the molding die,
(A) shows the gas flow path when the viscosity of the synthetic resin material used for molding the long shaft member is high,
(B) The gas flow path when the viscosity of the synthetic resin material used for molding the long shaft member is low is shown.
FIG. 27 is an explanatory view for explaining the relationship between the gas holding time and the dimensional accuracy of the long shaft member,
(A) is a characteristic curve diagram showing the relationship between the gas holding time and the dimensional accuracy of the long shaft member,
(B) is the elements on larger scale of the molding die near a gas nozzle, and is explanatory drawing for demonstrating the malfunction in case gas holding time is short.
FIG. 28 is an enlarged view in the vicinity of the gas nozzle of the molding die for explaining the relationship between the back pressure applied to the molten synthetic resin material on the molding machine main body side and the holding pressure of the pressurized gas. a) shows a state in which the resin injection portion is blocked by the fact that the back pressure is higher than the holding pressure of the pressurized gas,
(B) shows a state in which the resin injection portion is not blocked because the back pressure is lower than the holding pressure of the pressurized gas.
FIG. 29 shows another embodiment of a long shaft member forming apparatus according to the present invention,
It is explanatory drawing which shows schematic structure of the shaping | molding apparatus used for shaping | molding of the long axis member concerning this invention.
FIG. 30 is a block diagram showing another embodiment of the long shaft member forming apparatus according to the present invention and showing the relationship between the CPU and each control means.
FIG. 31 is an explanatory view showing another example of a method for forming a long shaft member according to the present invention,
(A) shows a state in which a synthetic resin material in a molten state is injected into a molded product cavity of a molding die,
(B) shows a state in which a pressurized gas is injected into the molten synthetic resin material and held for a predetermined time to be cooled and solidified,
(C) shows a state in which the gas of the pressurized gas existing in the hollow portion of the molded product formed by the cooling and solidification flows out,
(D) shows a cross-sectional view of the molded product taken out from the molding die,
(E) has shown the long-axis member formed by cut | disconnecting the unnecessary part of the molded article.
FIG. 32 is a partial cross-sectional view showing a process of forming a long shaft member using a conventional long shaft member forming mold.
FIG. 33 is a cross-sectional view showing an example of a long shaft member molded by a conventional long shaft member molding die.
FIG. 34 is a partial cross-sectional view showing a process of forming a long shaft member with an insert member inserted into one end using a conventional long shaft member forming mold.
FIG. 35 is a cross-sectional view showing a process of forming a long shaft member with insert members inserted at both ends using a conventional long shaft member forming mold.
[Explanation of symbols]
4 ... Synthetic resin material in the molten state
20 ... Long shaft member
21 ... Main unit
22 ... Hollow hole
23 ... Shaft
23 '... Metal shaft
24 ... through hole
28 ... Body cavity
32 ... Gas nozzle
34. Extra resin receiving cavity
O1 Rotation center axis
O2 ... Cavity center axis

Claims (8)

合成樹脂材料により形成された本体部が中心軸と略同心で該中心軸の延びる方向に長く延びる中空部を内部に有し、前記本体部の両端部に該本体部よりも小径の第１、第２軸部が形成され、前記各軸部には前記中空部を外部に連通する貫通穴が形成され、該貫通穴が前記中心軸と略同心であり、前記軸部が前記本体部の少なくとも一方の端部にインサートされた金属製のインサート部材により形成され、前記貫通穴が前記インサート部材に形成され、該インサート部材は前記貫通穴を構成する内周壁が前記本体部を形成する合成樹脂材料で被覆されていることを特徴とする長軸部材。 A main body portion formed of a synthetic resin material has a hollow portion that is substantially concentric with the central axis and extends long in the direction in which the central axis extends, and has a first diameter smaller than the main body portion at both ends of the main body portion, A second shaft portion is formed, and each shaft portion is formed with a through hole that communicates the hollow portion with the outside. The through hole is substantially concentric with the central axis , and the shaft portion is at least the main body portion. A synthetic resin material formed by a metal insert member inserted at one end, the through hole is formed in the insert member, and the insert member has an inner peripheral wall constituting the through hole forming the main body portion. A long shaft member that is covered with 前記貫通穴の直径が前記インサート部材の外部に露呈している端面から前記本体部に埋め込まれている端面までに渡って連続的に大きくなっている請求項１に記載の長軸部材。 2. The long shaft member according to claim 1 , wherein the diameter of the through hole continuously increases from an end surface exposed to the outside of the insert member to an end surface embedded in the main body portion . 前記本体部の外周面にその長手方向に沿って螺旋状の突起部が間隔を開けて複数個形成されていることを特徴とする請求項１又は請求項２に記載の長軸部材。 3. The long shaft member according to claim 1, wherein a plurality of spiral protrusions are formed on the outer peripheral surface of the main body along the longitudinal direction at intervals . 前記本体部の外周面にはその長手方向に沿って螺旋状の突起部が間隔を開けて複数個形成される長手方向突起形成領域が設けられ、該長手方向突起形成領域は前記本体部の周回り方向所定の角度範囲内の突起形成部と、前記所定の角度範囲外の突起非形成部とを有し、該突起非形成部の断面肉厚と前記突起形成部の断面肉厚とが略同一となるように、前記突起非形成部に前記突起形成部の外周面より低い外周面が形成されていることを特徴とする請求項１又は請求項２に記載の長軸部材。 The outer peripheral surface of the main body portion is provided with a longitudinal protrusion forming region in which a plurality of spiral protrusions are formed at intervals along the longitudinal direction, and the longitudinal protrusion forming region is provided around the periphery of the main body portion. A projection forming portion within a predetermined angular range in the rotation direction and a projection non-forming portion outside the predetermined angle range, and a cross-sectional thickness of the non-projection forming portion and a cross-sectional thickness of the projection forming portion are approximately 3. The long shaft member according to claim 1, wherein an outer peripheral surface lower than an outer peripheral surface of the projection forming portion is formed on the non-projection forming portion so as to be the same . 合成樹脂材料により形成された本体部が中心軸と略同心で該中心軸の延びる方向に長く延びる中空部を内部に有し、前記本体部の両端部に該本体部よりも小径の第１、第２軸部が形成され、前記各軸部には前記中空部を外部に連通する貫通穴が形成され、該貫通穴が前記中心軸と略同心であり、前記軸部が前記本体部の少なくとも一方の端部にインサートされた金属製のインサート部材により形成され、前記貫通穴が前記インサート部材に形成され、該インサート部材は前記貫通穴を構成する内周壁が前記本体部を形成する合成樹脂材料で被覆されている長軸部材の成形用金型であって、
前記本体部の中心軸に対応するキャビティ中心軸を有して前記本体部を成形する本体部キャビティと、前記本体部の両端部に形成された軸部を成形するための第１、第２軸部キャビティと、前記中空部を形成するための中空形成媒体を前記第１軸部キャビティを通じて注入する媒体注入部と、前記媒体注入部よりもキャビティ側に設けられて溶融樹脂を注入する樹脂注入部と、前記キャビティ内に充填された溶融樹脂のうち前記中空形成媒体の注入により該キャビティ内で余分となる余分樹脂を前記第２軸部キャビティを通じて受け入れる余分樹脂受入キャビティと、該余分樹脂受け入れキャビティを外部に連通する中空形成媒体流出部と、該中空形成媒体流出部を開閉する開閉バルブとを有する成形用金型。A main body portion formed of a synthetic resin material has a hollow portion that is substantially concentric with the central axis and extends long in the direction in which the central axis extends, and has a first diameter smaller than the main body portion at both ends of the main body portion, A second shaft portion is formed, and each shaft portion is formed with a through hole that communicates the hollow portion with the outside. The through hole is substantially concentric with the central axis , and the shaft portion is at least the main body portion. A synthetic resin material formed by a metal insert member inserted at one end, the through hole is formed in the insert member, and the insert member has an inner peripheral wall constituting the through hole forming the main body portion. A long-axis member molding die covered with
A main body cavity having a cavity central axis corresponding to the central axis of the main body, and forming the main body, and first and second shafts for forming the shaft formed at both ends of the main body. A cavity, a medium injection part for injecting a hollow forming medium for forming the hollow part through the first shaft cavity, and a resin injection part provided on the cavity side of the medium injection part for injecting molten resin An extra resin receiving cavity for receiving excess resin in the cavity by injection of the hollow forming medium out of the molten resin filled in the cavity through the second shaft cavity, and the extra resin receiving cavity. A molding die having a hollow forming medium outflow portion communicating with the outside and an open / close valve for opening and closing the hollow forming medium outflow portion . 前記樹脂注入部は前記中空媒体の注入される方向と交差される方向から溶融樹脂が注入されるように配置されていることを特徴とする請求項５に記載の長軸部材の成形用金型。6. The mold for molding a long shaft member according to claim 5, wherein the resin injecting portion is arranged so that a molten resin is injected from a direction intersecting a direction in which the hollow medium is injected. . 前記第１、第２軸部キャビティの少なくとも一方が、貫通穴を有するインサート部材の設置部とされている請求項５に記載の長軸部材の成形用金型。6. The long shaft member molding die according to claim 5, wherein at least one of the first and second shaft portion cavities is an installation portion of an insert member having a through hole. 合成樹脂材料により形成された本体部が中心軸と略同心で該中心軸の延びる方向に長く延びる中空部を内部に有し、前記本体部の両端部に該本体部よりも小径の第１、第２軸部が形成され、前記各軸部には前記中空部を外部に連通する貫通穴が形成され、前記貫通穴が前記中心軸と略同心で、前記軸部が前記本体部の少なくとも一方の端部にインサートされた金属製のインサート部材により形成され、前記貫通穴が前記インサート部材に形成され、該インサート部材は前記貫通穴を構成する内周壁が前記本体部を形成する合成樹脂材料で被覆されている長軸部材の成形用金型であって、
前記本体部の中心軸に対応するキャビティ中心軸を有して前記本体部を成形する本体部キャビティと、前記本体部の両端部に形成された軸部を成形するための第１、第２軸部キャビティと、前記第１軸部キャビティを介して前記本体部キャビティに前記中空部を形成するためのガスを注入するガス注入部と、前記ガス注入部よりもキャビティ側に設けられて前記ガスの注入方向と交差する方向から溶融樹脂を注入する樹脂注入部と、前記キャビティ内に充填された溶融樹脂のうち前記ガスの注入により該キャビティ内で余分となる余分樹脂を受け入れるために前記第２軸部キャビティを介して前記本体部キャビティと連通された余分樹脂受入キャビティと、該余分樹脂受け入れキャビティを外部に連通する中空形成媒体流出部と、該中空形成媒体流出部を開閉する開閉バルブとを有する成形用金型。A main body portion formed of a synthetic resin material has a hollow portion that is substantially concentric with the central axis and extends long in a direction in which the central axis extends, and has a first diameter smaller than the main body portion at both ends of the main body portion. A second shaft portion is formed, and each shaft portion is formed with a through hole that communicates the hollow portion with the outside. The through hole is substantially concentric with the central axis, and the shaft portion is at least one of the main body portions. Formed by a metal insert member inserted at the end of the insert member, the through hole is formed in the insert member, and the insert member is a synthetic resin material in which an inner peripheral wall constituting the through hole forms the main body portion. A mold for molding a long-axis member that is coated ,
A main body cavity having a cavity central axis corresponding to the central axis of the main body, and forming the main body, and first and second shafts for forming the shaft formed at both ends of the main body. and Department cavity, a gas injection unit for injecting gas for forming said hollow portion to the body portion cavity through the first shaft portion cavity, the gas provided in the cavity side of the gas injection section A resin injection portion for injecting a molten resin from a direction intersecting the injection direction, and the second shaft for receiving excess resin in the cavity due to the gas injection among the molten resin filled in the cavity. and extra resin receiving cavity communicates with the body portion cavity through the section cavity, a hollow forming medium outlet portion communicating the該余component resin receiving cavity to the outside, the hollow formation Mold and a closing valve for opening and closing the body outlet portion.
JP5738997A 1996-03-18 1997-03-12 Long shaft member and mold for molding Expired - Fee Related JP3761278B2 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
JP5738997A JP3761278B2 (en) 1996-03-18 1997-03-12 Long shaft member and mold for molding
US08/820,421 US6159415A (en) 1996-03-18 1997-03-18 Extended shaft and a mold of the extended shaft and an apparatus for molding the extended shaft and a method for molding the extended shaft
CN97109514A CN1083325C (en) 1996-03-18 1997-03-18 Elongated shaft member mold, apparatus, and method for molding elongated shaft member
CNB001325531A CN1139472C (en) 1996-03-18 1997-03-18 Slender shaft member
US09/172,137 US6117018A (en) 1996-03-18 1998-10-14 Elongated shaft member
CN00132554.XA CN1231342C (en) 1996-03-18 2000-11-27 Slender shaft member forming process

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
JP6093896 1996-03-18
JP13707996 1996-05-30
JP8-137079 1996-09-10
JP8-60938 1996-09-10
JP8-238987 1996-09-10
JP23898796 1996-09-10
JP5738997A JP3761278B2 (en) 1996-03-18 1997-03-12 Long shaft member and mold for molding

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JP3761278B2 true JP3761278B2 (en) 2006-03-29

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AU2004298491B2 (en) * 2003-12-10 2009-10-01 Cook Incorporated Injection moulding of functional cavities
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