JP3828669B2

JP3828669B2 - Method for producing synthetic resin hollow body

Info

Publication number: JP3828669B2
Application number: JP31656698A
Authority: JP
Inventors: 庸史山根; 光彌村田; 秀明小林
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1998-11-06
Filing date: 1998-11-06
Publication date: 2006-10-04
Anticipated expiration: 2018-11-06
Also published as: JP2000141399A

Description

【０００１】
【発明の属する技術分野】
本発明は合成樹脂製中空体の製造方法、特に、合成樹脂製中空体を構成する第１，第２半体を別々に保持した第１，第２型を閉じて両半体の合せ面相互を当接させ、次いで、両型の分割面に形成されて当接状態の両合せ面の外縁に臨む接合部成形用キャビティに溶融合成樹脂を充填して両半体を接合する製造方法の改良に関する。
【０００２】
【従来の技術】
従来、この種の中空体の製造方法としては、例えば、第１，第２型およびそれらの間に存する中間型を用いて第１，第２半体を射出成形し、次いで第１，第２半体をそれぞれ第１，第２型に保持させた状態において、前記のような手段によって両半体を接合する、といった方法が知られている。
【０００３】
【発明が解決しようとする課題】
しかしながら従来法においては、両半体の合せ面がそれぞれ両型の分割面と同一平面上に位置するように設定されているため、両型を閉じて両半体の合せ面相互を当接させたとき、両合せ面間の密着力が低い。その結果、前記接合部成形用キャビティに溶融合成樹脂を射出充填すると、その充填圧により両半体の各合せ面近傍部分が内方へ撓んで両合せ面間、第１半体および第１型間ならびに第２半体および第２型間にそれぞれ隙間が生じ、それらの隙間を通じて溶融合成樹脂が中空体内および両型のキャビティ形成面に漏出する、という問題があった。前記のような隙間は、射出成形直後、各半体が収縮して、その合せ面近傍部分が内方へ撓むことによっても生じる。
【０００４】
【課題を解決するための手段】
本発明は、両半体の両合せ面間からの溶融合成樹脂の漏出を確実に防止することができる、前記合成樹脂製中空体の製造方法を提供することを目的とする。
【０００５】
前記目的を達成するため本発明によれば、合成樹脂製中空体を構成する第１，第２半体を別々に保持した第１，第２型を閉じて両半体の合せ面相互を当接させ、次いで、両型の分割面に形成されて当接状態の両合せ面の外縁に臨む接合部成形用キャビティに溶融合成樹脂を充填して両半体を接合する合成樹脂製中空体の製造方法において、各半体は、その外周面周方向両端部に、両合せ面が半体厚さ範囲よりも外方へ延出して拡張されるように配置されると共に両型の凹部に嵌合する一対の突縁部を有し、両半体の少なくとも一方は、前記突縁部の、前記合せ面と反対側の部位から突出するアンカ凸部を、両型の少なくとも一方のアンカ凹部に係合させてその一方の型に保持され、型閉め前において、両半体の少なくとも一方の前記合せ面が、その半体を保持する両型の一方の分割面より突出した位置に在る、合成樹脂製中空体の製造方法が提供される。
【０００６】
例えば一方の半体である第１半体にアンカ凸部を設けると、その第１半体はアンカ凹、凸部を介して、例えば第１型に不動に保持されるので、射出成形直後の収縮によってその合せ面近傍部分が内方へ撓むことがない。したがって第２半体が前記収縮によってその合せ面近傍部分が内方へ撓んでいても、両型を閉じる過程で、第１半体の合せ面により第２半体の合せ面近傍部分を起して両合せ面を相互に当接させることができる。この場合、例えば第２半体の合せ面が第２型の分割面より突出した位置に在れば、その突出部分を第１半体の合せ面により押潰すか、またはその突出部分およびその近傍を弾性変形させることにより両合せ面の密着力を大いに高めることができる。この押潰しおよび弾性変形は、各突縁部の前記合せ面と反対側の部位が第１，第２型の各凹部内面に支持されていることから、確実に行われる。
【０００７】
このような手段を採用することにより接合部成形用キャビティへの溶融合成樹脂の射出充填に際し、その充填圧による両合せ面近傍部分の内方への撓みを防止して両合せ面間等からの溶融合成樹脂の漏出を確実に回避することができる。
【０００８】
【発明の実施の形態】
〔実施例Ｉ〕
図１，２において、合成樹脂よりなる中空体としての管状体１は、先ず図３に示す略樋状をなす第１，第２半体２，３を射出成形し、次いで両半体２，３を接合することによって製造される。
【０００９】
各半体２，３は、その周方向両端にそれぞれ合せ面４，５を有し、またその外周面周方向両端部に、両合せ面４，５が半体厚さ範囲ａよりも外方へ延出して拡張されるように配置された突縁部６，７をそれぞれ有する。
【００１０】
両半体２，３の少なくとも一方、実施例における第１半体２は、両突縁部６の、合せ面４と反対側の部位から半体離型方向ｂと平行に突出するアンカ凸部８を有する。これらのアンカ凸部８は、第１半体２の射出成形過程で成形されたもので、両半体２，３の接合過程では各アンカ凸部８を、それの成形用キャビティである第１型９の各アンカ凹部１０に係合させた成形状態に保ち、これにより第１半体２を第１型９に不動に保持させる。
【００１１】
型閉め前において、両半体２，３の少なくとも一方、実施例における第２半体３の両合せ面５は、その半体３を保持する両型９，１１の少なくとも一方、実施例における第２型１１の分割面１２より突出した位置に在る。両合せ面５の後背に存する両突出部分は、それぞれ型閉め過程で第１半体２の両合せ面４により押潰される潰れ代ｃである。第１半体２の両合せ面４と第１型９の分割面１３とは略同一平面上に位置する。この場合、両型９，１１において、分割面１２，１３と、キャビティ形成面９ａ，１１ａの、例えば最深部との間の距離はそれぞれｄであって、等しい。また第１半体２から両アンカ凸部８を、一方、第２半体３から両潰れ代ｃをそれぞれ除去すると、両半体２，３の形状は同じである。
【００１２】
図１，２に示すように、一対の合成樹脂製接合部１４が、両対向突縁部６，７の外面側に成形されており、これらの接合部１４により両半体２，３の接合が行われる。
【００１３】
以下、管状体１の製造方法について説明する。
【００１４】
（１）図４において、射出成形用成形型１５は左右の第１，第２型９，１１と、両型９，１１間に存する中間型１６とよりなり、それらの型９，１１，１６を閉じることによって、中間型１６と第１型９との間に第１半体２を成形するためのキャビティ１７が形成され、また中間型１６と第２型１１との間に第２半体３を成形するためのキャビティ１８が形成される。第１，第２型９，１１の分割面１２，１３において、接合部成形用キャビティを形成する各凹部１９，２０には中間型１６の各凸部２１，２２が嵌合して、それら凹部１９，２０の成形能は失われている。
【００１５】
（２）両キャビティ１７，１８に溶融合成樹脂を射出充填し、次いで第１，第２型９，１１から中間型１６を離間させると、図５に示すように、第１，第２半体２，３が第１，第２型９，１１に保持される。第２半体３の両合せ面５は第２型１１の分割面１２よりそれぞれ突出した位置に在り、また接合部成形用キャビティを形成する各凹部１９，２０が開放されている。
【００１６】
この場合、第１半体２は両アンカ凹、凸部８，１０を介して第１型９に不動に保持されているので、その凹弧面２３側にそれの支えとなる型が無くても、射出成形直後の収縮によってその両合せ面４近傍部分が内方へ撓むことがない。一方、第２半体３は、その凹弧面２４側に支えとなる型が無く、また前記のようなアンカ凹、凸部も無いことから前記収縮によってその合せ面近傍部分の一方、または両方が鎖線示のように内方へ撓むことがある。
【００１７】
次工程に備え、第１，第２型９，１１間にヒータ２５を配置して両半体２，３の各合せ面４，５を加熱する。
【００１８】
（３）図６に示すように、第１，第２型９，１１を閉じる。前記のように第１半体２は第１型９に不動に保持されているので、第２半体３が前記収縮によってその合せ面５近傍部分が内方へ撓んでいても、両型９，１１を閉じる過程で、第１半体２の各合せ面４により第２半体３の合せ面５近傍部分を起して両合せ面４，５を相互に当接させることができる。この場合、第２半体３の各合せ面５側には潰れ代ｃが存するので、それを第１半体２の各合せ面４によって押潰すことにより両合せ面４，５の密着力を大いに高めることができる。この押潰しは、各突縁部６，７の合せ面４，５と反対側の部位が第１，第２型９，１１の各凹部９ｂ，１１ｂ内面に支持されていることから、確実に行われる。また両型９，１１の両凹部１９，２０によって、当接状態の両合せ面４，５の外縁に臨む２つの接合部成形用キャビティ２６が形成される。
【００１９】
（４）図７に示すように、両キャビティ２６に溶融合成樹脂を射出充填して接合部１４を成形し、各接合部１４と両突縁部６，７とを溶着する。この場合、両半体２，３の両合せ面４，５は強く密着しているので、両接合部成形用キャビティ２６に溶融合成樹脂による充填圧が作用しても、その充填圧による両合せ面４，５近傍部分の内方への撓みが防止され、これにより両合せ面４，５間等からの溶融合成樹脂の漏出が回避される。
【００２０】
前記ヒータ２５による加熱、溶融合成樹脂の保有熱および両半体２，３の合せ面４，５の密着によって両半体２，３が接合され、両合せ面４，５は消失する。この場合、両半体２，３の各合せ面４，５が前記のように拡張されているので、それら合せ面４，５の面積の増加に伴い両半体２，３の接合強度が大いに高められる。
【００２１】
図８，９の例は、両半体２，３の合せ面４，５の一方、この例では第１半体２の合せ面４に凸部２７を、他方、したがって第２半体３の合せ面５に凹部２８をそれぞれ形成して、両合せ面４，５を凹凸嵌合させたものである。この凹凸嵌合構成には、図示の相互はぎ（合はぎ）構造の外に、さねはぎ構造等も含まれる。
【００２２】
このような凹凸嵌合構造を採用すると、接合部成形用キャビティ２６への溶融合成樹脂の充填圧に対する両合せ面４，５当接部の耐圧性を向上させ、また両合せ面４，５間にラビリンスを形成して前記樹脂の漏出防止を図ることができる。
【００２３】
この場合の潰れ代ｃは、第２半体３のクランク状合せ面５における分割面１２と平行な部位の後背に設けられる。
【００２４】
第１，第２半体２，３の射出成形およびそれらの接合に当っては、本出願人が先に提案した特開平９−２４８８４１号公報記載の成形装置を用いることも可能である。
〔実施例II〕
図１０に示す合成樹脂よりなる中空体としての管状体１は、実施例Ｉ同様に先ず図１１に示す略樋状をなす第１，第２半体２，３を射出成形し、次いで両半体２，３を接合することによって製造される。
【００２５】
各半体２，３は、その周方向両端にそれぞれ合せ面４，５を有し、またその外周面周方向両端部に、両合せ面４，５が半体厚さ範囲ａよりも外方へ延出して拡張されるように配置された突縁部６，７をそれぞれ有する。
【００２６】
両半体２，３の少なくとも一方、実施例における第１半体２は、両突縁部６の、合せ面４と反対側の部位から半体離型方向ｂと平行に突出するアンカ凸部８を有する。これらのアンカ凸部８は、第１半体２の射出成形過程で成形されたもので、両半体２，３の接合過程では各アンカ凸部８を、それの成形用キャビティである第１型９の各アンカ凹部１０に係合させた成形状態に保ち、これにより第１半体２を第１型９に不動に保持させる。
【００２７】
第２半体３は、第１半体２からアンカ凸部８を除去すればその第１半体２と同一の形状を有し、また第１，第２半体２，３の両合せ面４，５と、それらの射出成形用第１，第３型９，３０の分割面１３，３１とは略同一平面状に位置する。したがって、第１，第３型９，３０において、分割面１３，３１とキャビティ形成面９ａ，３０ａの、例えば最深部との間の距離はそれぞれｄであって等しい。
【００２８】
両半体２，３の接合過程に先立って、それら半体２，３の少なくとも一方、実施例では第２半体３は第３型３０より離型されて、前記距離ｅが第３型３０の前記距離ｄよりも短い、つまりｅ＜ｄである第２型１１に保持される。したがって型閉め前において、第２半体３の両合せ面５は、その半体３を保持する第２型１１の分割面１２より突出した位置に在る。両合せ面５の後背に存する両突出部分ｆおよびその近傍は、型閉め過程で第１半体２の両合せ面４により押圧されて弾性変形する。
【００２９】
図１，２に示すように、一対の合成樹脂製接合部１４が、両対向突縁部６，７の外面側に成形されており、これらの接合部１４により両半体２，３の接合が行われる。
【００３０】
以下、管状体１の製造方法について説明する。
【００３１】
（１）図１２において、射出成形用成形型１５は左右の第１，第３型９，３０と、両型９，３０間に存する中間型１６とよりなり、それらの型９，３０，１６を閉じることによって、中間型１６と第１型９との間に第１半体２を成形するためのキャビティ１７が形成され、また中間型１６と第３型３０との間に第２半体３を成形するためのキャビティ１８が形成される。第１型９の分割面１３において、接合部成形用キャビティを形成する凹部１９には中間型１６の凸部２１が嵌合して、それら凹部１９の成形能は失われている。第３型３０は前記のような凹部１９を持っていない。
【００３２】
（２）両キャビティ１７，１８に溶融合成樹脂を射出充填し、次いで第１，第３型９，３０から中間型１６を離間させると、第１，第２半体２，３が第１，第３型９，３０に保持される。第２半体３を第３型３０から離型して、図１３に示すように第２型１１に保持させる。第２半体３の両合せ面５は第２型１１の分割面１２よりそれぞれ突出した位置に在る。第２型１１は、その分割面１２に、第１型９の両凹部１９と協働して接合部成形用キャビティを形成する２つの凹部２０を有する。
【００３３】
この場合、第１半体２は両アンカ凹、凸部８，１０を介して第１型９に不動に保持されているので、その凹弧面２３側にそれの支えとなる型が無くても、射出成形直後の収縮によってその両合せ面４近傍部分が内方へ撓むことがない。一方、第２半体３は、その凹弧面２４側に支えとなる型が無く、また前記のようなアンカ凹、凸部も無いことから前記収縮によってその合せ面近傍部分の一方、または両方が前記のように内方へ撓むことがある。
【００３４】
（３）図１４に示すように、第１，第２型９，１１を閉じる。前記のように第１半体２は第１型９に不動に保持されているので、第２半体３が前記収縮によってその合せ面５近傍部分が内方へ撓んでいても、両型９，１１を閉じる過程で、第１半体２の各合せ面４により第２半体３の合せ面５近傍部分を起して両合せ面４，５を相互に当接させることができる。この場合、第２半体３の各合せ面５側には突出部分ｆが存するので、その突出部分ｆおよびその近傍を第１半体２の各合せ面４によって押圧することにより弾性変形させて両合せ面４，５の密着力を大いに高めることができる。この弾性変形は、各突縁部６，７の合せ面４，５と反対側の部位が第１，第２型９，１１の各凹部９ｂ，１１ｂ内面に支持されていることから、確実に行われる。また両型９，１１の両凹部１９，２０によって、当接状態の両合せ面４，５の外縁に臨む２つの接合部成形用キャビティ２６が形成される。
【００３５】
（４）図１５に示すように、両キャビティ２６に溶融合成樹脂を射出充填して接合部１４を成形し、各接合部１４と両突縁部６，７とを溶着する。この場合、両半体２，３の両合せ面４，５は強く密着しているので、両接合部成形用キャビティ２６に溶融合成樹脂による充填圧が作用しても、その充填圧による両合せ面４，５近傍部分の内方への撓みが防止され、これにより両合せ面４，５間等からの溶融合成樹脂の漏出が回避される。両半体２，３の合せ面４，５間は溶着されない。
【００３６】
離型後第２半体３は射出成形後の状態に復元する。
【００３７】
図８，９の例に実施例IIの方法を適用するは可能である。本発明における中空体としては、具体的にはエンジンの吸気マニホルド、エミッションコントローラ、一般的なエアダクト等を挙げることができ、また中空体には中空球状体も含まれる。
【００３８】
【発明の効果】
本発明によれば、前記のような手段を採用することによって、両半体の両合せ面間等からの溶融合成樹脂の漏出を確実に防止し得る、合成樹脂製中空体の製造方法を提供することができる。
【図面の簡単な説明】
【図１】合成樹脂製管状体の一例の要部斜視図である。
【図２】図１の２−２線断面図である。
【図３】第１，第２半体と第１，第２型との関係を示す断面図である。
【図４】第１，第２半体の射出成形用成形型の断面図である。
【図５】ヒータによる第１，第２半体の加熱過程を示す断面図である。
【図６】第１，第２型を閉じた状態を示す断面図である。
【図７】接合部成形用キャビティに溶融合成樹脂を射出充填した状態を示す断面図である。
【図８】第１，第２半体の他例の要部断面図である。
【図９】第１，第２半体の他例を保持した第１，第２型を閉じた状態を示す断面図である。
【図１０】合成樹脂製管状体の他例の断面図で、図２に対応する。
【図１１】第１半体および第１型の関係ならびに第２半体および第２，第３型の関係を示す断面図である。
【図１２】第１，第２半体の射出成形用成形型の断面図である。
【図１３】第２半体を第２型に保持させて第１半体に対向させた状態を示す断面図である。
【図１４】第１，第２型を閉じた状態を示す断面図である。
【図１５】接合部成形用キャビティに溶融合成樹脂を射出充填した状態を示す断面図である。
【符号の説明】
１…………………管状体（中空体）
２，３……………第１，第２半体
４，５……………合せ面
６，７……………突縁部
８…………………アンカ凸部
９，１１…………第１，第２型
９ｂ，１１ｂ……凹部
１０………………アンカ凹部
１２，１３………分割面
２６………………接合部成形用キャビティ
２７………………凸部
２８………………凹部
ａ…………………半体厚さ範囲[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a synthetic resin hollow body, in particular, by closing the first and second molds separately holding the first and second halves constituting the synthetic resin hollow body, Improvement of the manufacturing method in which both halves are joined by filling the melt molding resin into the joint forming cavity formed on the split surfaces of both molds and facing the outer edges of the mating surfaces in contact with each other About.
[0002]
[Prior art]
Conventionally, as a method of manufacturing this type of hollow body, for example, the first and second halves are injection molded using the first and second molds and the intermediate mold existing between them, and then the first and second molds are used. In a state where the halves are held in the first and second molds, a method is known in which both halves are joined by the above-described means.
[0003]
[Problems to be solved by the invention]
However, in the conventional method, since the mating surfaces of both halves are set to be on the same plane as the split surfaces of both molds, both molds are closed and the mating surfaces of both halves are brought into contact with each other. The adhesion between the mating surfaces is low. As a result, when the molten synthetic resin is injected and filled into the joint forming cavity, the portions near the mating surfaces of both halves are bent inward by the filling pressure, and the first half and the first mold are formed between the mating surfaces. There was a problem that gaps were formed between the second half and the second mold, and the molten synthetic resin leaked through the gaps to the hollow body and the cavity forming surfaces of both molds. The gap as described above also occurs when each half is contracted immediately after injection molding, and the portion near the mating surface is bent inward.
[0004]
[Means for Solving the Problems]
An object of the present invention is to provide a method for producing a hollow body made of a synthetic resin, which can reliably prevent leakage of a molten synthetic resin from between both mating surfaces of both halves.
[0005]
In order to achieve the above object, according to the present invention, the first and second molds separately holding the first and second halves constituting the synthetic resin hollow body are closed and the mating surfaces of the two halves are brought into contact with each other. Next, a synthetic resin hollow body that is formed on the split surfaces of both molds and is filled with a molten synthetic resin in a joint molding cavity that faces the outer edges of the mating surfaces in contact with each other, and joins both halves. In the manufacturing method, each half body is arranged at both ends in the circumferential direction of the outer peripheral surface so that the mating surfaces extend outward from the half body thickness range and fit into the recesses of both molds. A pair of projecting edges, and at least one of the two halves has an anchor projection projecting from a portion of the projecting edge opposite to the mating surface into at least one anchor recess of both molds. Engaged and held in one of the molds, and before closing the mold, at least one of the mating surfaces of both halves is In the position protruding from one of the split surfaces of the mold to hold the halves method for producing a synthetic resin hollow body is provided.
[0006]
For example, when an anchor protrusion is provided on the first half which is one half, the first half is held immovably on the first mold, for example, via the anchor recess and protrusion. The portion near the mating surface is not bent inward due to the contraction. Therefore, even when the second half of the second half is bent inward due to the contraction, in the process of closing both molds, the second half of the second half is raised by the second half. Thus, the mating surfaces can be brought into contact with each other. In this case, for example, if the mating surface of the second half is located at a position protruding from the split surface of the second mold, the projecting portion is crushed by the mating surface of the first half, or the projecting portion and its vicinity. It is possible to greatly enhance the adhesion of both mating surfaces by elastically deforming the two. This crushing and elastic deformation is reliably performed because the portion of each protruding edge opposite to the mating surface is supported by the inner surfaces of the concave portions of the first and second molds.
[0007]
By adopting such means, when the molten synthetic resin is injected and filled into the joint molding cavity, the inward bending of the vicinity of both the mating surfaces due to the filling pressure is prevented, and the gap between the both mating surfaces is prevented. It is possible to reliably avoid the leakage of the molten synthetic resin.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Example I
1 and 2, a tubular body 1 as a hollow body made of a synthetic resin is formed by first injection-molding first and second halves 2 and 3 having a substantially bowl shape shown in FIG. 3 is manufactured by joining.
[0009]
Each half body 2, 3 has mating surfaces 4, 5 at both ends in the circumferential direction, and both mating surfaces 4, 5 are outward from the half thickness range a at both ends in the outer circumferential surface direction. And projecting edge portions 6 and 7 arranged so as to be extended.
[0010]
At least one of the two halves 2 and 3, the first half 2 in the embodiment, is an anchor protrusion that protrudes in parallel with the half-body release direction b from a portion of the two projecting edges 6 opposite to the mating surface 4. 8 has. These anchor protrusions 8 are formed in the injection molding process of the first half body 2, and in the joining process of both halves 2, 3, each anchor protrusion 8 is a first forming cavity. The mold 9 is kept in a molded state engaged with each anchor recess 10, and thereby the first half 2 is held immovably by the first mold 9.
[0011]
Before closing the mold, at least one of both halves 2 and 3, both mating surfaces 5 of the second half 3 in the embodiment are at least one of both dies 9 and 11 holding the half 3, in the second embodiment. It exists in the position which protruded from the division surface 12 of 2 type | mold 11. FIG. Both projecting portions existing behind the mating surfaces 5 are crushing margins c crushed by the mating surfaces 4 of the first half 2 in the mold closing process. The mating surfaces 4 of the first half 2 and the dividing surface 13 of the first mold 9 are located on substantially the same plane. In this case, in both molds 9 and 11, the distance between the dividing surfaces 12 and 13 and the cavity forming surfaces 9a and 11a, for example, the deepest part is d and equal. Further, when both anchor protrusions 8 are removed from the first half 2 and both crushing allowances c are removed from the second half 3, the shapes of both halves 2 and 3 are the same.
[0012]
As shown in FIGS. 1 and 2, a pair of synthetic resin joints 14 are formed on the outer surface sides of the opposing projecting edges 6 and 7, and the joints 14 join the halves 2 and 3 together. Is done.
[0013]
Hereinafter, the manufacturing method of the tubular body 1 is demonstrated.
[0014]
(1) In FIG. 4, the injection mold 15 includes left and right first and second molds 9 and 11 and an intermediate mold 16 existing between the molds 9 and 11. , A cavity 17 for forming the first half 2 is formed between the intermediate mold 16 and the first mold 9, and a second half is formed between the intermediate mold 16 and the second mold 11. A cavity 18 for molding 3 is formed. On the split surfaces 12 and 13 of the first and second molds 9 and 11, the convex portions 21 and 22 of the intermediate mold 16 are fitted into the concave portions 19 and 20 forming the joint forming cavities. The molding ability of 19, 20 is lost.
[0015]
(2) When both the cavities 17 and 18 are injected and filled with molten synthetic resin, and then the intermediate mold 16 is separated from the first and second molds 9 and 11, as shown in FIG. 2 and 3 are held by the first and second molds 9 and 11. The mating surfaces 5 of the second half 3 are located at positions projecting from the dividing surface 12 of the second mold 11, and the recesses 19 and 20 forming the joint forming cavity are opened.
[0016]
In this case, since the first half body 2 is held immovably by the first mold 9 via both anchor concaves and convex portions 8 and 10, there is no mold to support it on the concave arc surface 23 side. However, the portion near both the mating surfaces 4 is not bent inward due to the shrinkage immediately after the injection molding. On the other hand, since the second half 3 does not have a supporting mold on the concave arc surface 24 side, and there is no anchor concave or convex portion as described above, one or both of the vicinity of the mating surface due to the contraction. May be bent inward as indicated by the chain line.
[0017]
In preparation for the next process, a heater 25 is disposed between the first and second molds 9 and 11 to heat the mating surfaces 4 and 5 of both halves 2 and 3.
[0018]
(3) Close the first and second molds 9 and 11 as shown in FIG. As described above, since the first half body 2 is held immovably by the first mold 9, even if the second half body 3 is bent inward due to the contraction, the both mold 9 , 11 in the process of closing the mating surfaces 5 of the second half 3 by the mating surfaces 4 of the first half 2 to bring the mating surfaces 4 and 5 into contact with each other. In this case, since the crush margin c exists on each mating surface 5 side of the second half 3, the adhesion force between the mating surfaces 4, 5 can be increased by crushing it with each mating surface 4 of the first half 2. Can greatly increase. Since this crushing is supported by the inner surfaces of the recesses 9b and 11b of the first and second molds 9 and 11 on the opposite side of the mating surfaces 4 and 5 of the protruding edges 6 and 7, it is ensured. Done. Further, two joint forming cavities 26 facing the outer edges of the mating surfaces 4 and 5 in contact with each other are formed by the concave portions 19 and 20 of both the molds 9 and 11.
[0019]
(4) As shown in FIG. 7, both the cavities 26 are injected and filled with a molten synthetic resin to form the joints 14, and the joints 14 and the projecting edges 6, 7 are welded together. In this case, since the mating surfaces 4 and 5 of both halves 2 and 3 are in close contact with each other, even if the filling pressure by the molten synthetic resin acts on the cavity 26 for molding both joints, both mating by the filling pressure is performed. Inward bending of the portions in the vicinity of the surfaces 4 and 5 is prevented, thereby preventing leakage of the molten synthetic resin from between the mating surfaces 4 and 5.
[0020]
The two halves 2 and 3 are joined by the heating by the heater 25, the heat retained by the molten synthetic resin, and the adhesion of the mating surfaces 4 and 5 of the two halves 2 and 3, and the mating surfaces 4 and 5 disappear. In this case, since the mating surfaces 4 and 5 of both halves 2 and 3 are expanded as described above, the bonding strength of the halves 2 and 3 greatly increases as the area of the mating surfaces 4 and 5 increases. Enhanced.
[0021]
In the example of FIGS. 8 and 9, one of the mating surfaces 4 and 5 of both halves 2 and 3, in this example, the mating surface 4 of the first half 2 has a convex portion 27 and the other, therefore A concave portion 28 is formed on the mating surface 5 and the mating surfaces 4 and 5 are concavo-convexly fitted. This concave-convex fitting configuration includes a tongue-and-groove structure and the like in addition to the illustrated mutual peel (joint) structure.
[0022]
By adopting such a concave-convex fitting structure, the pressure resistance of the abutting portions 4 and 5 against the filling pressure of the molten synthetic resin into the joint forming cavity 26 is improved, and the space between the both mating surfaces 4 and 5 is improved. A labyrinth can be formed in the resin to prevent leakage of the resin.
[0023]
The crush allowance c in this case is provided at the back of the portion of the second half 3 parallel to the dividing surface 12 in the crank-shaped mating surface 5.
[0024]
In the injection molding of the first and second halves 2 and 3 and their joining, it is possible to use a molding apparatus described in Japanese Patent Laid-Open No. 9-248841 previously proposed by the present applicant.
Example II
A tubular body 1 as a hollow body made of a synthetic resin shown in FIG. 10 is formed by first injection-molding first and second halves 2 and 3 having a substantially bowl shape shown in FIG. It is manufactured by joining the bodies 2 and 3 together.
[0025]
Each half body 2, 3 has mating surfaces 4, 5 at both ends in the circumferential direction, and both mating surfaces 4, 5 are outward from the half thickness range a at both ends in the outer circumferential surface direction. And projecting edge portions 6 and 7 arranged so as to be extended.
[0026]
At least one of the two halves 2 and 3, the first half 2 in the embodiment, is an anchor protrusion that protrudes in parallel with the half-body release direction b from a portion of the two projecting edges 6 opposite to the mating surface 4. 8 has. These anchor protrusions 8 are formed in the injection molding process of the first half body 2, and in the joining process of both halves 2, 3, each anchor protrusion 8 is a first forming cavity. The mold 9 is kept in a molded state engaged with each anchor recess 10, and thereby the first half 2 is held immovably by the first mold 9.
[0027]
The second half 3 has the same shape as the first half 2 when the anchor protrusions 8 are removed from the first half 2, and both mating surfaces of the first and second halves 2 and 3. 4 and 5 and the dividing surfaces 13 and 31 of the first and third molds 9 and 30 for injection molding are located on substantially the same plane. Therefore, in the first and third molds 9 and 30, the distance between the dividing surfaces 13 and 31 and the cavity forming surfaces 9a and 30a, for example, the deepest part is d and equal.
[0028]
Prior to the joining process of both halves 2, 3, at least one of the halves 2, 3, in the embodiment, the second half 3 is released from the third mold 30, and the distance e is equal to the third mold 30. The second mold 11 is shorter than the distance d, that is, e <d. Therefore, before the mold closing, the mating surfaces 5 of the second half 3 are located at positions protruding from the dividing surface 12 of the second mold 11 that holds the half 3. Both projecting portions f existing in the back of the mating surfaces 5 and the vicinity thereof are pressed by the mating surfaces 4 of the first half 2 and elastically deformed in the mold closing process.
[0029]
As shown in FIGS. 1 and 2, a pair of synthetic resin joints 14 are formed on the outer surface sides of the opposing projecting edges 6 and 7, and the joints 14 join the halves 2 and 3 together. Is done.
[0030]
Hereinafter, the manufacturing method of the tubular body 1 is demonstrated.
[0031]
(1) In FIG. 12, the mold 15 for injection molding is composed of left and right first and third molds 9 and 30 and an intermediate mold 16 existing between both molds 9 and 30, and these molds 9, 30, 16 Is closed to form a cavity 17 for molding the first half 2 between the intermediate mold 16 and the first mold 9, and a second half between the intermediate mold 16 and the third mold 30. A cavity 18 for molding 3 is formed. On the dividing surface 13 of the first mold 9, the convex portions 21 of the intermediate mold 16 are fitted into the concave portions 19 forming the joint forming cavities, and the molding ability of these concave portions 19 is lost. The third mold 30 does not have the concave portion 19 as described above.
[0032]
(2) When both the cavities 17 and 18 are injected and filled with molten synthetic resin, and then the intermediate mold 16 is separated from the first and third molds 9 and 30, the first and second halves 2 and 3 become the first and second halves 2 and 3, respectively. It is held in the third mold 9,30. The second half 3 is released from the third mold 30 and is held by the second mold 11 as shown in FIG. The mating surfaces 5 of the second half 3 are located at positions protruding from the dividing surface 12 of the second mold 11. The second mold 11 has two recesses 20 on its dividing surface 12 that form joint-forming cavities in cooperation with both recesses 19 of the first mold 9.
[0033]
In this case, since the first half body 2 is held immovably by the first mold 9 via both anchor concaves and convex portions 8 and 10, there is no mold to support it on the concave arc surface 23 side. However, the portion near both the mating surfaces 4 is not bent inward due to the shrinkage immediately after the injection molding. On the other hand, since the second half 3 does not have a supporting mold on the concave arc surface 24 side, and there is no anchor concave or convex portion as described above, one or both of the vicinity of the mating surface due to the contraction. May be deflected inward as described above.
[0034]
(3) Close the first and second molds 9 and 11 as shown in FIG. As described above, since the first half body 2 is held immovably by the first mold 9, even if the second half body 3 is bent inward due to the contraction, the both mold 9 , 11 in the process of closing the mating surfaces 5 of the second half 3 by the mating surfaces 4 of the first half 2 to bring the mating surfaces 4 and 5 into contact with each other. In this case, since there is a protruding portion f on each mating surface 5 side of the second half 3, the protruding portion f and its vicinity are elastically deformed by pressing each mating surface 4 of the first half 2. The adhesion between the mating surfaces 4 and 5 can be greatly increased. This elastic deformation is ensured because the portions of the projecting edge portions 6 and 7 opposite to the mating surfaces 4 and 5 are supported by the inner surfaces of the concave portions 9b and 11b of the first and second molds 9 and 11, respectively. Done. Further, two joint forming cavities 26 facing the outer edges of the mating surfaces 4 and 5 in contact with each other are formed by the concave portions 19 and 20 of both the molds 9 and 11.
[0035]
(4) As shown in FIG. 15, melted synthetic resin is injected and filled into both cavities 26 to form the joints 14, and the joints 14 and the projecting edges 6 and 7 are welded together. In this case, since the mating surfaces 4 and 5 of both halves 2 and 3 are in close contact with each other, even if the filling pressure by the molten synthetic resin acts on the cavity 26 for molding both joints, both mating by the filling pressure is performed. Inward bending of the portions in the vicinity of the surfaces 4 and 5 is prevented, thereby preventing leakage of the molten synthetic resin from between the mating surfaces 4 and 5. The joining surfaces 4 and 5 of the two halves 2 and 3 are not welded.
[0036]
After release, the second half 3 is restored to the state after injection molding.
[0037]
It is possible to apply the method of Example II to the examples of FIGS. Specific examples of the hollow body in the present invention include an engine intake manifold, an emission controller, a general air duct, and the like, and the hollow body includes a hollow spherical body.
[0038]
【The invention's effect】
According to the present invention, there is provided a method for producing a synthetic resin hollow body that can reliably prevent leakage of a molten synthetic resin from between both mating surfaces of both halves by employing the above-described means. can do.
[Brief description of the drawings]
FIG. 1 is a perspective view of an essential part of an example of a synthetic resin tubular body.
FIG. 2 is a sectional view taken along line 2-2 of FIG.
FIG. 3 is a cross-sectional view showing the relationship between the first and second halves and the first and second molds.
FIG. 4 is a sectional view of a first and second half mold for injection molding.
FIG. 5 is a cross-sectional view showing the heating process of the first and second halves by the heater.
FIG. 6 is a cross-sectional view showing a state in which the first and second molds are closed.
FIG. 7 is a cross-sectional view showing a state where a molten synthetic resin is injected and filled into a joint forming cavity.
FIG. 8 is a cross-sectional view of a main part of another example of the first and second halves.
FIG. 9 is a sectional view showing a state in which the first and second molds holding other examples of the first and second halves are closed.
FIG. 10 is a cross-sectional view of another example of the synthetic resin tubular body and corresponds to FIG.
FIG. 11 is a cross-sectional view showing the relationship between the first half and the first type, and the relationship between the second half and the second and third types.
FIG. 12 is a cross-sectional view of a first and second half mold for injection molding.
FIG. 13 is a cross-sectional view showing a state in which the second half is held in the second mold and is opposed to the first half.
FIG. 14 is a cross-sectional view showing a state in which the first and second molds are closed.
FIG. 15 is a cross-sectional view showing a state where a molten synthetic resin is injected and filled into a joint forming cavity.
[Explanation of symbols]
1 ………………… Tubular body (hollow body)
2, 3 ............ 1st and 2nd half bodies 4, 5 ............ Mating surfaces 6, 7 ............ Projection edge 8 ........................... Anchor projections 9, 11 ............ first and second molds 9b, 11b ...... recess 10 ............ anchor recesses 12, 13 ......... divided surface 26 ........................... joint forming cavity 27 ............ …… Convex 28 ……………… Concave a ………………… Half thickness range

Claims

The first and second molds (9, 11) holding the first and second halves (2, 3) constituting the synthetic resin hollow body (1) are closed and the halves (2, 3) are closed. Next, the mating surfaces (4, 5) are brought into contact with each other, and then formed on the split surfaces (12, 13) of both molds (9, 11) to the outer edges of the mating surfaces (4, 5) in the abutting state. In the manufacturing method of the synthetic resin hollow body in which the joint molding cavity (26) facing is filled with molten synthetic resin and both halves (2, 3) are joined,
Each half body (2, 3) is arranged at both ends in the circumferential direction of the outer peripheral surface so that both mating surfaces (4, 5) extend outward from the half body thickness range (a). And a pair of projecting edges (6, 7) that fit into the recesses (9b, 11b) of both molds (9, 11), and at least one (2) of both halves (2, 3) The anchor protrusion (8) protruding from the portion of the projecting edge (6) opposite to the mating surface (4) is used as the anchor recess (10) of at least one (9) of both molds (9, 11). ) And is held by one of the molds (9),
Prior to mold closing, the mating surface (5) of at least one (3) of both halves (2, 3) is one of the (11) of both molds (9, 11) holding that half (3). A method for producing a hollow body made of synthetic resin, wherein the method is located at a position protruding from the dividing surface (12).

A convex portion (27) is formed on one (4) of the mating surfaces (4, 5) of both halves (2, 3), and a concave portion (28) is formed on the other, so that both mating surfaces (4, 5) are formed. The method for producing a hollow body made of synthetic resin according to claim 1, wherein the concave and convex portions are fitted.