JP3902511B2 - Grid structure and manufacturing method thereof - Google Patents

Description

【００２２】
ここでは成形時のグリッド構造１の熱膨張率をゼロに設定したので、式（１）でα_g をゼロとして炭素繊維の体積含有率Ｖ_f を求める。実施の形態１の強化繊維および樹脂の組み合わせの場合、Ｖ_f の値はおよそ６０％である。ここで求めたＶ_f の値よりも、実際には５％〜１０％程度高めになるように、したがって炭素繊維の体積含有率が６５％〜７０％となるように、樹脂母材と炭素繊維を混合してプリプレグを作製する。
【００２３】
▲３▼試験片を作製する（ステップＳＴ２）。
その後、このプリプレグを積層して加熱・硬化させ、熱膨張率を測定するための試験片を作製する。
▲４▼試験片の熱膨張率の測定を行い、目標値（所望の値）と比較する（ステップＳＴ３）。
試験片の熱膨張率の測定を、例えばレーザー熱干渉型熱膨張測定装置ＬＩＸ−１（真空理工社製）を用いて行う。これは、１×１０^-8／℃の精度で熱膨張率を測定することができる装置である。上述したように、試験片のＶ_f の値は高めになっているため、熱膨張率が負である炭素繊維の効果が強く出て、ここで得られる熱膨張率の値は目標値（ここではゼロ）よりも若干低くなっている。
【００２４】
▲５▼修正試験片を作製する（ステップＳＴ４）。
試験片の熱膨張率の測定結果を鑑み、修正試験片を作製する。具体的には、試験片と比較してＶ_f の値が低くなるように、最初に用意した半硬化の樹脂フィルムをプリプレグの間に適宜挟みながら積層していく。その後、積層したプリプレグを加熱・硬化させ、修正試験片を作製する。
▲６▼修正試験片の熱膨張率を測定する（ステップＳＴ５）。
修正試験片の熱膨張率を上述の測定装置を用いて行い、目標値と比較する。そして、測定値が目標値と比較して、その差が十分に小さい場合は後述する本工程に移り、グリッド構造１を作製する（ステップＳＴ６）。
【００２５】
▲７▼修正試験片の熱膨張率の測定値が目標値と比較して十分に小さくない場合は、プリプレグの間に挟みこむ樹脂フィルムの厚さを調整したり、プリプレグの層数（積層する枚数）と樹脂フィルムの層数を調整したりしながら（ステップＳＴ７）、修正試験片の熱膨張率が目標の数値になるまでステップＳＴ４〜ステップＳＴ６に示す工程を繰り返し、最適なフィルムの厚さとフィルムの層数とを決定する。ここでは、実際に０±２×１０^-8／℃になるまで作業を繰り返した。
【００２６】
以上のステップＳＴ１〜ステップＳＴ７の熱膨張率調整工程により、ＣＦＲＰ中の強化繊維と樹脂（樹脂母材）との間の熱歪みを釣り合わせることができ、したがって熱膨張率を調整することができる。
【００２７】
２．本工程（ステップＳＴ８）
▲１▼チューブ（単位構造）を作製する。
熱膨張率調整工程により最終的に作製された修正試験片にしたがって、これと同様に作製された積層済みのプリプレグを、例えば四角柱状の型に巻きつけ、それを所望の幅に切断することにより、チューブ１ａを形成する。
【００２８】
▲２▼チューブ（単位構造）を複数集積させてグリッド構造１を作製する。
隣り合うチューブ１ａ同士の外壁を互いに接着し、格子状のグリッド構造１を作製する。
【００２９】
以上の方法で製作されたグリッド構造１の構造全体の熱膨張率を測定したところ、０±１×１０^-7／℃の範囲内の値であった。
【００３０】
以上のように、この実施の形態１によれば、全体の熱膨張率の値が０±１×１０^-7／℃の範囲内であるため、光学機器等、高い熱的寸法安定性が求められる光学機器への適用が可能であるという効果が得られる。
また、この実施の形態１によれば、熱膨張率調整工程により、積層済みのプリプレグを試験片として熱膨張率の微調整を行った後、本工程に移りグリッド構造を作製するので、従来の方法と比較してより高い精度で熱膨張率が調整でき、全体の熱膨張率の値を安定して０±１×１０^-7／℃の範囲内とすることができるという効果が得られる。
【００３１】
なお、ここでは熱膨張率がゼロになるように調整した例を挙げたが、構造に対する要求に応じて熱膨張率がゼロ以外の特定の値となるように調整することも可能である。
また、ここでは強化繊維の体積含有率を調整することのみにより、強化繊維と樹脂（樹脂母材）との間の熱歪みを釣り合わせたが、グリッド構造１の面内方向と厚さ方向のそれぞれに配向している強化繊維の量を変化させた上で、強化繊維と樹脂との混合比を調整して、方向毎に異なる熱膨張率を持つように調整することも可能である。
【００３２】
実施の形態２．
図３はこの発明の実施の形態２によるグリッド構造の構成を説明するための概略的な分解斜視図である。図４はこの発明の実施の形態２によるグリッド構造の作製方法を説明するための概略図である。図において、２はＣＦＲＰ（ＦＲＰ）からなり、熱膨張率が０±１×１０^{- ７}／℃の範囲内であるグリッド構造である。２ａは強化繊維を束にしたものを樹脂母材に含浸した単位強化繊維束である。２ｂは単位強化繊維束２ａを一定の間隔で平行に配列した第一の強化繊維束群である。２ｃは単位強化繊維束２ａが第一の強化繊維束群２ｂに直交する方向に一定の間隔で平行に配列された第二の強化繊維束群である。
【００３３】
グリッド構造２は、第一の強化繊維束群２ｂと第二の強化繊維束群２ｃが互い違いに積み重ねられて構成されており、全体として格子状の形状となっている。強化繊維束群を積み重ねる方法としては、例えば文献２（Continous Filament Wound Isogrid Structures for Space Applications；19993 ASM Conf Proc）に開示されているフィラメントワインディング（円筒状の型の上に繊維束を巻いて成形体を製作する方法）、あるいはファイバープレースメント（面上に繊維束を順次置いていく方法）等の方法が挙げられる。
【００３４】
３は後述する液状の樹脂母材４が満たされた容器であり、３ａは容器３の底部に設けられた絞り穴である。４は容器３内に入っている液状の樹脂母材である。この容器３の上側から強化繊維の束を投入し、液状の樹脂母材４をくぐらせて絞り穴３ａから引き出すことにより、樹脂母材４を含浸した単位強化繊維束２ａが得られる。強化繊維の束に含ませる樹脂母材４の量は、絞り穴３ａの径に依存する。
【００３５】
次に、実施の形態２のグリッド構造２の作製方法について説明をする。
１．熱膨張率調整工程
▲１▼強化繊維を束にしたものと、液状の樹脂母材４を用意し、試料を作製する。
ここでは、強化繊維としてＹＳＨ−６０Ａ（Nippon Graphite Fiber社製）を用い、樹脂母材４として熱硬化性シアネートエステル樹脂ＥＸ１５１５（Bryte Techonologies社製）を用いる。実施の形態１と同様に、強化繊維の体積含有率を調整することにより強化繊維と樹脂との間の熱歪みの釣り合わせを行う。
▲２▼グリッド構造２の所望の熱膨張率から、強化繊維の体積含有率を求める。
成形時のグリッド構造２の熱膨張率の所望の値をゼロに設定し、式（１）により強化繊維（ここでは炭素繊維）の体積含有率Ｖ_f の値を求める。実施の形態２の強化繊維および樹脂の組合せの場合、Ｖ_f の値はおよそ６０％である。
▲３▼試料を作製する。
まず、容器３の上側から強化繊維の束を投入し、これを液状の樹脂母材４にくぐらせて絞り穴３ａから引き出すことにより樹脂母材４に浸した強化繊維の束を作製する。これを加熱・硬化させたものを熱膨張率を測定するための試料とする。
▲４▼試料の熱膨張率の測定を行い、目標値（所望の値）と比較する。
試料の熱膨張率の測定を、例えばレーザー熱干渉型熱膨張測定装置ＬＩＸ−１（真空理工社製）を用いて行う。
【００３６】
▲５▼修正試料を作製する。
試料の熱膨張率の測定結果を鑑み、修正試料を作製する。具体的には、試料と比較して修正試料の熱膨張率の値が目標値に近づくように、絞り穴３ａの径の大きさを変えた容器３を用意する。例えば、熱膨張率の値が負であれば強化繊維の束に含ませる樹脂母材４の量を増やすために径を大きくした修正絞り穴を有する修正容器を用意し、これを用いて試料と同様の方法で修正試料を作製する。
▲６▼修正試料の熱膨張率を測定する。
修正試料の熱膨張率を例えば上述の測定装置を用いて行い、目標値と比較する。そして、測定値が目標値と比較して、その差が十分に小さい場合は、後述する本工程に移り、グリッド構造２を作成する。
【００３７】
▲７▼修正試料の熱膨張率の測定値が目標値と比較して十分に小さくない場合は、上述の▲５▼〜▲６▼の工程を、修正試料の熱膨張率の測定値が目標の値となるまで繰り返し、このときの修正絞り穴の径を求め、この径の修正絞り穴を有する修正容器を実際にグリッド構造２を作製するときの本工程で用いる容器３として採用する。
ここでは、試料の熱膨張率の測定値が実際に０±２×１０^-8／℃になるまで作業を繰り返した。
【００３８】
以上の熱膨張率調整工程による作業でＣＦＲＰ中の炭素繊維の体積含有率が調整できたことになり、したがって強化繊維と樹脂母材との間の熱歪みを釣り合わせることができたことになる。
【００３９】
２．本工程
熱膨張率調整工程により求められた大きさの径を有する修正絞り穴を持つ修正容器を用いて、樹脂母材４が満たされたこの修正容器に強化繊維束を投入して樹脂母材４にくぐらせ、修正絞り穴より強化繊維束を引き脱すことにより、単位強化繊維束２ａを作製する。この単位強化繊維束２ａを一定の間隔を持って平行に配列した強化繊維束群２ｂと、これに直交する方向に単位強化繊維束２ａを一定の間隔を持って平行に配列した強化繊維束群２ｃとを交互に積み重ね、格子状のグリッド構造２を作製する。
【００４０】
以上の方法で製作されたグリッド構造２の構造全体の熱膨張率を測定したところ、０±５×１０^-8／℃の範囲内の値であった。
【００４１】
以上のように、この実施の形態２よれば、熱膨張率の値が０±１×１０^-7／℃の範囲内であるため、光学機器等、高い熱的寸法安定性が求められる光学機器への適用が可能であるという効果が得られる。
また、この実施の形態２によれば、熱膨張率調整工程により、グリッド構造２を構成するＦＲＰの中間素材である強化繊維の束の熱膨張率の微調整を行った後、本工程に移りグリッド構造を作製するので、従来の方法と比較してより高い精度で熱膨張率が調整できるという効果が得られる。
【００４２】
実施の形態３．
次に、この発明の実施の形態３によるグリッド構造について説明する。実施の形態３のグリッド構造は、二種の異なる炭素繊維（強化繊維）を含むＣＦＲＰ（ＦＲＰ）からなり、全体の熱膨張率が０±１×１０^-7／℃の範囲内であるグリッド構造である。
【００４３】
グリッド構造に含まれる二種の異なる炭素繊維は、ここではＸＮ−８０Ａ（Nippon Graphite Fiber社製）と、Ｍ４０Ｊ（東レ製）とした。また、樹脂母材としてシアネートエステル樹脂ＲＳ−３（ＹＬＡ社製）を用いた。ＸＮ−８０Ａはピッチ系の炭素繊維であり、繊維が走る方向の熱膨張率は−１．４×１０^-6／℃、弾性率が７８５ＧＰａである。また、Ｍ４０ＪはＰＡＮ系の炭素繊維であり、繊維が走る方向の熱膨張率は−１．２×１０^-6／℃、弾性率が３７８ＧＰａである。また、ＲＳ−３の熱膨張率は６０×１０^-6／℃、弾性率は３ＧＰａである。
【００４４】
以上の二種類の炭素繊維と樹脂母材を用いて、例えば実施の形態１のグリッド構造の作製方法によりグリッド構造１を作製し、全体の熱膨張率を測定したところ、０±１×１０^-7／℃の範囲内の値であった。また、機械特性試験（引っ張りおよび圧縮試験）を行ったところ、実施の形態１のグリッド構造１と比較して、剛性の向上が確認された。
【００４５】
以上のように、この実施の形態３のグリッド構造によれば、熱膨張率の値が０±１×１０^-7／℃の範囲内であるため、実施の形態１と同様の効果が得られる。
また、実施の形態３のグリッド構造によれば、熱膨張率および合成の異なる二種類の炭素繊維と、樹脂母材とからなるため、熱膨張率を所望の値に調整しながらも、様々な弾性率を有する構造を実現することが可能であり、構造の設計の自由度を大きくすることができるという効果が得られる。
【００４６】
なお、ここではピッチ系炭素繊維とＰＡＮ系炭素繊維の二種類の炭素繊維を組み合わせたが、アラミド繊維等の他の熱膨張率の低い繊維を用いても同様の効果が得られる。また、これらのどの繊維を組み合わせても良いし、二種類以上であれば最適な種類の繊維の組み合わせを採用することができる。
また、ここでは実施の形態１のグリッド構造１に適用した例を示したが、実施の形態２のグリッド構造２に適用することもできる。
また、格子状のグリッド構造に限らず、実施の形態１および実施の形態２に示されたグリッド構造の作製方法により作製された他の形状のグリッド構造においても適用できる。
【００４７】
実施の形態４．
図５はこの発明の実施の形態４によるグリッド構造の説明図であり、図５（ａ）はグリッド構造の概略的な分解斜視図、図５（ｂ）はグリッド構造をグリッド構造１におけるチューブ１ａが配列されたある一列において、壁面に直交する方向で切った断面図である。図において、１１は後述する表皮１１ａを備えたグリッド構造である。１１ａは、グリッド構造１の片側表面を覆い、かつグリッド構造１と同じ熱膨張率を有する表皮である。
すでに述べてあるように、グリッド構造１の熱膨張率は、実施の形態１のグリッド構造１の作製方法により０±１×１０^-7／℃の範囲内に調整することが可能である。また、表皮となるＦＲＰ板の熱膨張率は、一般的に知られる種々の方法での作製により１×１０^-7／℃の精度で調整が可能であるため、グリッド構造１１全体としての熱膨張率の値を０±１×１０^-7／℃の範囲内にすることができる。
【００４８】
以上のように、この実施の形態４のグリッド構造１１によれば、構造全体の熱膨張率の値が０±１×１０^-7／℃の範囲内であるため、光学機器等、高い熱的寸法安定性が求められる光学機器への適用が可能であるという効果が得られる。
また、表皮１１ａでグリッド構造１の表面を覆っているため、グリッド構造１が補強された形となり、構造全体の強度や剛性が向上する上に、表皮１１ａを反射鏡や機器を搭載するための面として使用可能になり、利用範囲が広くなるという効果が得られる。
【００４９】
なお、実施の形態４では表皮１１ａがグリッド構造１の片側のみに設けられた例を示したが、使用目的により両側表面を覆うサンドイッチ構造にしても良い。
また、グリッド構造１１はグリッド構造１を表皮１１ａで覆った例につき示したが、グリッド構造２に適用することもできる。また、実施の形態１および実施の形態２に示されたグリッド構造の作製方法により作製された他の形状のグリッド構造に適用することもできる。
【００５０】
実施の形態５．
図６はこの発明の実施の形態５によるグリッド構造の説明図であり、図６（ａ）はグリッド構造の概略的な分解斜視図、図６（ｂ）はグリッド構造をグリッド構造１におけるチューブ１ａが配列されたある一列において、壁面に直交する方向で切った断面図である。図において、２１はグリッド構造１の両側表面を覆う、後述する表皮２１ａを備えたグリッド構造である。２１ａは、グリッド構造１の両側表面を覆い、かつグリッド構造１との間の熱歪みが釣り合っている表皮である。
【００５１】
グリッド構造２１は、温度変化が生じたときにグリッド構造１に生じる熱歪みと、表皮２１ａに生じる熱歪みとのバランスが取れるように調整してある。具体的には、例えば以下のｉ）〜ｉｉｉ）の方法により、両者の熱歪みを釣り合わせる。
ｉ）実施の形態１のグリッド構造の作製方法によりグリッド構造１を作製してグリッド構造１および表皮２１ａの間の熱膨張率および剛性の調整をする。
ｉｉ）機械加工によりグリッド構造１の厚さを調整する。
ｉｉｉ）上記のｉ）およびｉｉ）の方法の中から複数の方法を用いて、グリッド構造の熱膨張率、剛性、厚さのいずれか、あるいはそのうちの二つ、またはいずれも調整する。
【００５２】
以下、グリッド構造１と表皮２１ａとの間の熱歪みを釣り合わせる方法の一例を示す。
例えば、グリッド構造１の強化繊維としてＸＮ−８０Ａ（Nippon Graphite Fiber社製）を用い、表皮２１ａの強化繊維としてＭ４０Ｊ（東レ製）を用い、樹脂母材としてシアネートエステル樹脂ＥＸ１５１５を用いるとする。グリッド構造１および表皮２１ａの双方の強化繊維の体積含有率を約６０％とすれば、グリッド構造１の熱膨張率の値は負となり、表皮２１ａの熱膨張率の値は正となる。
そこで、グリッド構造１の厚さと熱膨張率の値とを、実施の形態１のグリッド構造の作製方法により調整する。その後、完成したグリッド構造１と表皮２１ａとを貼り合わせ、グリッド構造２１を作製する。
このような方法により作製されたグリッド構造２１全体の熱膨張率を測定したところ、０±１×１０^-7／℃の範囲内であることが確認された。
【００５３】
以上のように、この実施の形態５のグリッド構造２１によれば、構造全体の熱膨張率の値が０±１×１０^-7／℃の範囲内である。また、グリッド構造２１によれば、表皮２１ａでグリッド構造１の表面を覆っている。したがって、実施の形態４と同様の効果が得られる。
【００５４】
なお、実施の形態５では表皮２１ａがグリッド構造１の両側表面を覆うサンドイッチ構造とした例を示したが、表皮２１ａはその目的により片側のみに設けても良い。
また、グリッド構造２１はグリッド構造１を表皮２１ａで覆った例につき示したが、グリッド構造２に適用することも、実施の形態１および実施の形態２に示されたグリッド構造の作製方法により作製された他の形状のグリッド構造に適用することもできる。
【００５５】
実施の形態６．
図７はこの発明の実施の形態６によるグリッド構造の説明図であり、図７（ａ）はグリッド構造の概略的な分解斜視図、図７（ｂ）はグリッド構造を、グリッド構造１におけるチューブ１ａが配列されたある一列において、壁面に直交する方向で切った断面図である。図において、３１は後述する表皮３１ａ、および表皮３１ａを覆う金属コーティング層３１ｂを備えたグリッド構造である。３１ａはグリッド構造１の両側表面を覆う表皮であり、３１ｂは表皮３１ａのそれぞれを覆う金属コーティング層である。
【００５６】
グリッド構造３１は、温度変化が生じたときにグリッド構造１に生じる熱歪みと、表皮３１ａに生じる熱歪みと、金属コーティング層３１ｂに生じる熱歪みとのバランスが取れるように調整してある。具体的には、例えば以下のア）〜エ）の方法により、三者の熱歪みを釣り合わせる。
ア）実施の形態１のグリッド構造の作製方法によりグリッド構造１を作製してグリッド構造１および表皮３１ａとの間の熱膨張率および剛性の調整をする。
イ）機械加工によりグリッド構造１の厚さを調整する。
ウ）機械加工、または化学的な処理により金属コーティング層３１ｂの厚さを調整する。
エ）上記のア）〜ウ）の方法の中から複数の方法を用いて、グリッド構造３１の熱膨張率、剛性、厚さ、金属コーティング層の厚さのいずれか、あるいは二種類以上のいずれか、あるいはいずれも調整する。
【００５７】
ここでは、グリッド構造１の強化繊維としてＸＮ−８０Ａ（Nippon Graphite Fiber社製）を用い、表皮３１ａの強化繊維としてＭ４０Ｊ（東レ製）を用い、樹脂母材としてシアネートエステル樹脂ＥＸ１５１５を用い、金属コーティング層３１ｂの材料としてニッケルを用い、三者の熱歪みの調整を上述の方法を用いて行った。その後、完成したグリッド構造１と金属コーティング層３１ｂを設けた表皮３１ａとを貼り合わせ、グリッド構造３１を作製する。
このような方法により作製されたグリッド構造３１全体の熱膨張率を測定したところ、０±１×１０^-7／℃の範囲内であり、光学反射鏡として十分に使用可能であることが確認された。
【００５８】
以上のように、この実施の形態６のグリッド構造３１によれば、構造全体の熱膨張率の値が０±１×１０^-7／℃の範囲内である。したがって、実施の形態１と同様の効果が得られる。
また、金属コーティング層３１ｂを設けた表皮３１ａでグリッド構造１の表面を覆っている。したがって、実施の形態４と同様の効果が得られる。
また、金属コーティング層３１ｂで表皮３１ａの表面を覆っているため、熱的寸法安定性に優れた光学反射鏡として使用することができる。
【００５９】
なお、実施の形態６では表皮３１ａおよび金属コーティング層３１ｂがグリッド構造１の両側表面を覆うサンドイッチ構造とした例を示したが、表皮３１ａおよび金属コーティング層３１ｂは目的により片側のみに設けても良い。
また、グリッド構造３１はグリッド構造１を表皮３１および金属コーティング層３１ｂで覆った例につき示したが、グリッド構造２を覆う場合に適用することも、実施の形態１および実施の形態２に示されたグリッド構造の作製方法により作製された他の形状のグリッド構造に適用することもできる。
【００６０】
なお、実施の形態１および実施の形態３〜６では、チューブ（単位構造）１ａの形状は、その断面形状が四角形である場合について説明したが、単位構造の形状はこれに限らず、同一の単位構造を複数集積することが可能な形状であれば良い。
【００６１】
【発明の効果】
以上のように、この発明によれば、繊維強化プラスチックを構成する、熱膨張率がマイナスの強化繊維と、樹脂母材との間の熱歪みが釣り合っていることにより、全体における熱膨張率が０±１×１０^-7／℃の範囲内であり、筒状の単位構造が複数集積して一つの網状の構造を構成するようにしたので、光学機器等、高い熱的寸法安定性が求められる光学機器への適用が可能であるという効果がある。
【００６２】
この発明によれば、ａ）強化繊維に半硬化の樹脂母材を含浸させたプリプレグを積層した試験片を作製し、この試験片の熱膨張率の測定を行う。ｂ）前工程の熱膨張率の測定値よりも所望の値に近づけるために、半硬化の樹脂フィルムを適宜間に挟みながら上記プリプレグを積層した修正試験片を作製し、この修正試験片の熱膨張率の測定を行う。ｃ）樹脂フィルムの厚さおよび積層数を変化させながら、所望の値となるまでｂ）工程を繰り返す、という、ａ）〜ｃ）の工程を含む熱膨張率調整工程と、所望の値となったときの修正試験片を用いて成形される、筒状の単位構造を複数集積させてなる網状のグリッド構造を形成する本工程とを含むようにグリッド構造の作製方法を構成したので、従来の方法と比較してより高い精度で熱膨張率が調整でき、全体の熱膨張率の値を安定して０±１×１０^-7／℃の範囲内とすることができるという効果がある。
【００６３】
この発明によれば、Ａ）強化繊維を束ねた強化繊維束を、液状の樹脂母材が満たされ、かつ底部に絞り穴が設けられた容器に投入し、絞り穴から上記強化繊維束を引き出すことにより、強化繊維束に上記樹脂母材を浸した試料を作製し、この試料の熱膨張率の測定を行う。Ｂ）前工程の熱膨張率の測定値よりも所望の値に近づけるために、液状の樹脂母材が満たされ、かつ前工程の容器とは径の大きさを変化させた修正絞り穴を有する修正容器に強化繊維束を投入し、修正絞り穴から強化繊維束を引き出すことにより、前工程とは液状の樹脂母材の附着量を変化させた修正試料を作製し、この修正試料の熱膨張率の測定を行う。Ｃ）所望の値となるまで、Ｂ）工程を繰り返す、という、Ａ）〜Ｃ）の工程を含む熱膨張率調整工程と、所望の値となったときの上記修正容器を用いて、強化繊維束に樹脂母材を浸すことにより単位強化繊維束を多数作製し、この単位強化繊維束を一定の間隔を持って平行に配列させた第一の繊維束群と、単位強化繊維束を、第一の繊維束群に対して一定の角度を持つ方向に、一定の間隔を持って平行に配列させた第二の繊維束群とを、交互に積み重ねていくことにより、網状のグリッド構造を形成する本工程とを含むようにグリッド構造の作製方法を構成したので、従来の方法と比較してより高い精度で熱膨張率が調整でき、全体の熱膨張率の値を安定して０±１×１０^-7／℃の範囲内とすることができるという効果がある。
【図面の簡単な説明】
【図１】 この発明の実施の形態１によるグリッド構造の構成を説明するための概略的な斜視図である。
【図２】 この発明の実施の形態１によるグリッド構造の作製方法の手順を示すフロー図である。
【図３】 この発明の実施の形態２によるグリッド構造の構成を説明するための概略的な分解斜視図である。
【図４】 この発明の実施の形態２によるグリッド構造の作製方法を説明するための概略図である。
【図５】 この発明の実施の形態４によるグリッド構造の説明図である。
【図６】 この発明の実施の形態５によるグリッド構造の説明図である。
【図７】 この発明の実施の形態６によるグリッド構造の説明図である。
【図８】 従来のグリッド構造の構成を示す概略的な説明図である。
【符号の説明】
１，２，１１，２１，３１ グリッド構造、１ａ チューブ（単位構造）、２ａ 単位強化繊維束、２ｂ 第一の強化繊維束群、２ｃ 第二の強化繊維束群、３ 容器、３ａ 絞り穴、４ 樹脂母材、１１ａ，２１ａ，３１ａ 表皮、３１ｂ 金属コーティング層。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a grid structure that is a lightweight structure that is applied to aerospace materials, has high strength and rigidity, and has a low coefficient of thermal expansion, and a manufacturing method thereof.
[0002]
[Prior art]
Structures applied to aerospace materials are required to be lightweight and have high strength and rigidity, and various forms of structures such as honeycomb sandwich panels have been proposed. As one of them, a grid structure using fiber reinforced plastic (FRP) has attracted attention in recent years.
The grid structure is a net-like structure in which a plurality of unit structures of the same shape are integrated, and has a physical characteristic that the coefficient of thermal expansion can be adjusted. Therefore, thermal dimensional stability is regarded as important. For example, application to structures for optical instruments is being promoted.
[0003]
FIG. 8 is an explanatory diagram of a conventional grid structure disclosed in Reference 1 (Composite Grid Structure with Near-Zero Thermally Induced Deflection, AIAA-2000-1476).
In the figure, reference numeral 41 denotes a grid structure. Reference numeral 42 denotes a rectangular tube made of carbon fiber reinforced plastic (CFRP). Reference numeral 43 denotes a first rib, and 43a denotes a slit provided on the upper side of the first rib and a lower part facing it. 44 is a second rib, and 44 a is a slit provided at the same position as the first rib 43 of the second rib 44. The first rib 43 and the second rib 44 are fitted in the slits 43a and 44a in a direction orthogonal to each other to form a lattice-like structure. The square tube 42 is bonded and fitted to each inner wall of a square portion surrounded by walls on all sides of the lattice-like structure.
[0004]
Next, a method for manufacturing the grid structure 41 will be described.
1. The first rib 43 and the second rib 44 are cut out from the CFRP plate material.
2. A rectangular tube 42 made of CFRP is formed.
FRP has a different coefficient of thermal expansion between the direction in which the fiber runs and the direction in which it intersects, and this is used to adjust the orientation angle of the carbon fiber so that the coefficient of thermal expansion of the rectangular tube 42 becomes a desired value. Thus, the square tube 42 is formed.
3. The second rib 44 is fitted into the first rib 43 to form a lattice-like structure.
4). A square tube 42 is fitted into the inner wall of the lattice structure and bonded.
[0005]
Since the grid structure 41 manufactured as described above can be adjusted so that the thermal expansion coefficient of the square tube 42 is close to zero, the thermal expansion coefficient of the entire structure can also be close to zero. is there.
[0006]
[Problems to be solved by the invention]
In the conventional grid structure, as described above, the control of the thermal expansion coefficient depends on the adjustment of the orientation angle of the reinforcing fiber of the FRP. Therefore, accurate adjustment is difficult, and the adjustment error of the thermal expansion coefficient is 1 × 10.^-7/ ° C ~ 1 × 10^-6/ ° C or so. In this case, there is a problem that it is difficult to apply to an optical apparatus or the like in which thermal dimensional stability is regarded as important.
[0007]
The present invention has been made to solve the above-described problems, and an object thereof is to obtain a grid structure capable of accurately adjusting the coefficient of thermal expansion.
Moreover, it aims at obtaining the preparation method of such a grid structure.
[0009]
[Means for Solving the Problems]
  The grid structure according to the present invention isThe thermal expansion coefficient between the reinforcing fiber having a negative thermal expansion coefficient and the resin base material constituting the fiber reinforced plastic is balanced, so that the overall thermal expansion coefficient is 0 ± 1 × 10. ^-7 Within the range of / ° C.A plurality of cylindrical unit structures are integrated to form one net-like structure.
[0010]
In the grid structure according to the present invention, a unit reinforcing fiber bundle in which reinforcing fibers dipped in a resin base material are bundled, a first fiber bundle group in which the unit reinforcing fiber bundles are arranged in parallel at a constant interval, The second fiber bundle groups arranged in parallel with a constant interval in a direction having a constant angle with respect to the first fiber bundle group are configured to be alternately stacked.
[0011]
In the grid structure according to the present invention, the reinforcing fibers are formed by combining two or more kinds of reinforcing fibers having different coefficients of thermal expansion and rigidity.
[0012]
The grid structure according to the present invention includes a skin that covers one or both surfaces of the grid structure and has the same thermal expansion coefficient as that of the grid structure.
[0013]
The grid structure according to the present invention is provided with a skin that covers one or both surfaces of the grid structure and has a thermal strain balanced with the grid structure.
[0014]
In the grid structure according to the present invention, the surface of the skin is provided with a metal coating layer in which the thermal strain between the skin and the skin is balanced.
[0015]
In the method for producing a grid structure according to the present invention, a) a test piece obtained by laminating a prepreg in which a reinforcing fiber is impregnated with a semi-cured resin base material is produced, and the thermal expansion coefficient of the test piece is measured. b) In order to bring it closer to the desired value than the measured value of the coefficient of thermal expansion in the previous step, a modified test piece was prepared by laminating the prepreg while sandwiching a semi-cured resin film as appropriate. The expansion coefficient is measured. c) Thermal expansion coefficient adjustment step including steps a) to c), in which the step b) is repeated until the desired value is reached while changing the thickness and the number of layers of the resin film, and the desired value is obtained. And the present step of forming a net-like grid structure formed by accumulating a plurality of cylindrical unit structures formed using the corrected test piece.
[0016]
In the grid structure manufacturing method according to the present invention, A) a reinforcing fiber bundle in which reinforcing fibers are bundled is charged into a container filled with a liquid resin base material and provided with a throttle hole at the bottom, and the above-mentioned reinforcement is made from the throttle hole. By pulling out the fiber bundle, a sample in which the resin base material is immersed in the reinforcing fiber bundle is prepared, and the thermal expansion coefficient of the sample is measured. B) In order to bring it closer to a desired value than the measured value of the coefficient of thermal expansion in the previous process, the liquid resin base material is filled, and the diameter of the diameter of the previous process container is changed. By introducing the reinforcing fiber bundle into the correction container and pulling out the reinforcing fiber bundle from the correction restriction hole, a correction sample is produced in which the amount of liquid resin base material attached is changed from the previous process, and the thermal expansion of this correction sample is made. Measure the rate. C) Reinforcing fiber bundle using the thermal expansion coefficient adjusting process including the processes of A) to C) that repeat the process B) until the desired value is reached, and the correction container when the desired value is reached. A large number of unit reinforcing fiber bundles are produced by immersing the resin base material in the first fiber bundle group in which the unit reinforcing fiber bundles are arranged in parallel with a certain interval, and the unit reinforcing fiber bundles are A net-like grid structure is formed by alternately stacking the second fiber bundle group arranged in parallel with a constant interval in a direction having a constant angle with respect to the fiber bundle group. This step is included.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is a schematic perspective view for explaining a configuration of a grid structure according to Embodiment 1 of the present invention. FIG. 2 is a flowchart showing the procedure of the method for manufacturing the grid structure according to the first embodiment of the present invention. In the figure, 1 is made of fiber reinforced plastic (FRP), and the overall coefficient of thermal expansion is 0 ± 1 × 10.^-7It is a grid structure within the range of / ° C. Here, it was made of carbon fiber reinforced plastic (CFRP). Reference numeral 1 a denotes a tube (unit structure) which is one unit structure constituting the grid structure 1. Here, the tube 1a has a rectangular cylindrical shape, and a plurality of the tubes 1a are integrated to form a grid structure 1 having a lattice shape. Moreover, the outer wall of the adjacent tube 1a is adhere | attached. Steps ST1 to ST8 show steps 1 to 8.
[0018]
The overall thermal expansion coefficient of the grid structure 1 is stably 0 ± 1 × 10^-7The range of / ° C. indicates that the thermal expansion coefficient of the grid structure of the molded product is controlled by balancing the thermal strain between the carbon fiber (reinforced fiber) constituting the CFRP and the resin base material. by. Balancing thermal strain means balancing the strains that occur in both the reinforcing fibers and the resin matrix when temperature changes occur (so that the magnitude of strain is uniform). . The balance of thermal strain will be described later.
[0019]
Next, a method for manufacturing the grid structure 1 according to the first embodiment will be described.
1. Thermal expansion coefficient adjustment process (step ST1 to step ST7)
(1) A prepreg material and a semi-cured resin film are prepared, and a prepreg is prepared so as to balance the thermal strain between the reinforcing fiber and the resin (resin base material) (step ST1).
A prepreg is a sheet-like material in which a semi-cured resin base material is infiltrated into reinforced fibers. The prepreg is stacked in a desired shape, heated, and cured to obtain a molded product of fiber reinforced plastic. Here, YSH-60A (Nippon Graphite Fiber) is used as the reinforcing fiber, and thermosetting cyanate ester resin EX1515 (Bryte Techonology) is used as the resin base material. Any semi-cured resin film may be used as long as it can be heated and cured together with the prepreg. Here, the same thermosetting cyanate ester resin EX1515 as that contained in the prepreg is used as a film.
[0020]
The coefficient of thermal expansion in the direction in which the fibers of the reinforcing fiber YSH-60A run is about -1.4 × 10^-6/ ° C., and the thermal expansion coefficient of the resin EX1515 is 34 × 10^-6Since it is / ° C., the thermal expansion coefficient of the molded product can be controlled by balancing the thermal strains of the two. Specifically, the above-described thermal strain is balanced by adjusting the volume content of the reinforcing fibers.
[0021]
(2) From the desired coefficient of thermal expansion of the grid structure 1, the volume content of reinforcing fibers is determined.
Α is the coefficient of thermal expansion of the resin matrix._m, E_mAnd the coefficient of thermal expansion of the carbon fiber is α_f, E_f, The volume content is V_fThen, the thermal expansion coefficient α of the grid structure 1_gCan be approximated by equation (1).
[Expression 1]

[0022]
Here, since the coefficient of thermal expansion of the grid structure 1 at the time of molding was set to zero, α in Equation (1)_gThe volume content of carbon fiber V_fAsk for. In the case of the combination of the reinforcing fiber and the resin of the first embodiment, V_fThe value of is approximately 60%. V obtained here_fIn practice, the resin base material and the carbon fiber are mixed so that the volume content of the carbon fiber is 65% to 70%, so that the volume content of the carbon fiber is 65% to 70%. Make it.
[0023]
(3) A test piece is prepared (step ST2).
Thereafter, the prepreg is laminated and heated and cured to prepare a test piece for measuring the coefficient of thermal expansion.
(4) The coefficient of thermal expansion of the test piece is measured and compared with a target value (desired value) (step ST3).
The measurement of the thermal expansion coefficient of the test piece is performed using, for example, a laser thermal interference thermal expansion measuring device LIX-1 (manufactured by Vacuum Riko Co., Ltd.). This is 1x10^-8This is a device that can measure the coefficient of thermal expansion with an accuracy of / ° C. As mentioned above, the V of the test piece_fSince the value of is high, the effect of carbon fiber having a negative coefficient of thermal expansion is strong, and the value of the coefficient of thermal expansion obtained here is slightly lower than the target value (here, zero) .
[0024]
{Circle around (5)} A corrected test piece is prepared (step ST4).
In view of the measurement result of the coefficient of thermal expansion of the test piece, a corrected test piece is prepared. Specifically, compared to the test piece, V_fThe semi-cured resin film prepared first is laminated while being appropriately sandwiched between prepregs so that the value of is low. Thereafter, the laminated prepreg is heated and cured to produce a corrected test piece.
(6) The coefficient of thermal expansion of the corrected specimen is measured (step ST5).
The coefficient of thermal expansion of the corrected test piece is performed using the above-described measuring apparatus and compared with the target value. And when a measured value is compared with a target value and the difference is small enough, it moves to this process mentioned later and produces grid structure 1 (Step ST6).
[0025]
(7) If the measured value of the coefficient of thermal expansion of the modified test piece is not sufficiently small compared to the target value, the thickness of the resin film sandwiched between the prepregs can be adjusted, or the number of prepreg layers (stacked) The number of layers) and the number of layers of the resin film (step ST7), and the processes shown in steps ST4 to ST6 are repeated until the coefficient of thermal expansion of the corrected specimen reaches a target value, and the optimum film thickness and Determine the number of layers in the film. Here, it is actually 0 ± 2 × 10^-8The operation was repeated until it reached / ° C.
[0026]
Through the thermal expansion coefficient adjustment process in steps ST1 to ST7 described above, the thermal strain between the reinforcing fiber in CFRP and the resin (resin base material) can be balanced, and thus the thermal expansion coefficient can be adjusted. .
[0027]
2. This process (step ST8)
(1) A tube (unit structure) is produced.
In accordance with the modified test piece finally produced by the thermal expansion coefficient adjustment process, the laminated prepreg produced in the same manner is wound around, for example, a quadrangular prism mold and cut into a desired width. The tube 1a is formed.
[0028]
(2) A grid structure 1 is manufactured by accumulating a plurality of tubes (unit structures).
The outer walls of adjacent tubes 1a are bonded to each other to produce a grid-like grid structure 1.
[0029]
When the coefficient of thermal expansion of the entire structure of the grid structure 1 manufactured by the above method was measured, 0 ± 1 × 10^-7The value was within the range of / ° C.
[0030]
As described above, according to the first embodiment, the value of the overall coefficient of thermal expansion is 0 ± 1 × 10.^-7Since it is in the range of / ° C., an effect that it can be applied to an optical apparatus such as an optical apparatus that requires high thermal dimensional stability is obtained.
In addition, according to the first embodiment, since the thermal expansion coefficient is finely adjusted by using the laminated prepreg as a test piece in the thermal expansion coefficient adjustment process, the process proceeds to this process to produce the grid structure. Compared with the method, the coefficient of thermal expansion can be adjusted with higher accuracy, and the value of the overall coefficient of thermal expansion is stabilized to 0 ± 1 × 10^-7The effect that it can be within the range of / ° C. is obtained.
[0031]
Although an example in which the coefficient of thermal expansion is adjusted to zero has been described here, it is also possible to adjust the coefficient of thermal expansion to a specific value other than zero according to the requirements for the structure.
Further, here, the thermal strain between the reinforcing fiber and the resin (resin base material) is balanced only by adjusting the volume content of the reinforcing fiber, but in the in-plane direction and the thickness direction of the grid structure 1 It is also possible to adjust the mixing ratio between the reinforcing fiber and the resin after changing the amount of reinforcing fibers oriented in each direction so as to have a different coefficient of thermal expansion for each direction.
[0032]
Embodiment 2. FIG.
FIG. 3 is a schematic exploded perspective view for explaining the configuration of the grid structure according to the second embodiment of the present invention. FIG. 4 is a schematic diagram for explaining a method of manufacturing a grid structure according to the second embodiment of the present invention. In the figure, 2 is made of CFRP (FRP), and the coefficient of thermal expansion is 0 ± 1 × 10.^{- 7}It is a grid structure within the range of / ° C. 2a is a unit reinforcing fiber bundle obtained by impregnating a resin base material with a bundle of reinforcing fibers. Reference numeral 2b denotes a first reinforcing fiber bundle group in which unit reinforcing fiber bundles 2a are arranged in parallel at regular intervals. Reference numeral 2c denotes a second reinforcing fiber bundle group in which the unit reinforcing fiber bundles 2a are arranged in parallel at regular intervals in a direction orthogonal to the first reinforcing fiber bundle group 2b.
[0033]
The grid structure 2 is configured by alternately stacking the first reinforcing fiber bundle group 2b and the second reinforcing fiber bundle group 2c, and has a lattice shape as a whole. As a method of stacking reinforcing fiber bundle groups, for example, filament winding disclosed in Reference 2 (Continous Filament Wound Isogrid Structures for Space Applications; 19993 ASM Conf Proc) And a method such as fiber placement (a method of sequentially placing fiber bundles on the surface).
[0034]
3 is a container filled with a liquid resin base material 4 to be described later, and 3 a is a throttle hole provided in the bottom of the container 3. Reference numeral 4 denotes a liquid resin base material contained in the container 3. By feeding a bundle of reinforcing fibers from the upper side of the container 3 and passing through the liquid resin base material 4 and pulling it out from the throttle hole 3a, a unit reinforcing fiber bundle 2a impregnated with the resin base material 4 is obtained. The amount of the resin base material 4 included in the bundle of reinforcing fibers depends on the diameter of the throttle hole 3a.
[0035]
Next, the manufacturing method of the grid structure 2 of Embodiment 2 is demonstrated.
1. Thermal expansion coefficient adjustment process
(1) A bundle of reinforcing fibers and a liquid resin base material 4 are prepared, and a sample is prepared.
Here, YSH-60A (manufactured by Nippon Graphite Fiber) is used as the reinforcing fiber, and thermosetting cyanate ester resin EX1515 (manufactured by Bryte Techonologies) is used as the resin base material 4. Similar to Embodiment 1, the thermal strain balance between the reinforcing fibers and the resin is performed by adjusting the volume content of the reinforcing fibers.
(2) From the desired coefficient of thermal expansion of the grid structure 2, the volume content of reinforcing fibers is determined.
The desired value of the coefficient of thermal expansion of the grid structure 2 at the time of molding is set to zero, and the volume content V of the reinforcing fiber (here, carbon fiber) according to the formula (1)_fFind the value of. In the case of the combination of the reinforcing fiber and the resin of the second embodiment, V_fThe value of is approximately 60%.
(3) Prepare a sample.
First, a bundle of reinforcing fibers is introduced from the upper side of the container 3, passed through the liquid resin base material 4, and pulled out from the throttle hole 3 a to prepare a bundle of reinforcing fibers immersed in the resin base material 4. A sample obtained by heating and curing this is used as a sample for measuring the coefficient of thermal expansion.
(4) The coefficient of thermal expansion of the sample is measured and compared with a target value (desired value).
The thermal expansion coefficient of the sample is measured using, for example, a laser thermal interference thermal expansion measurement device LIX-1 (manufactured by Vacuum Riko Co., Ltd.).
[0036]
(5) Prepare a corrected sample.
In view of the measurement result of the coefficient of thermal expansion of the sample, a corrected sample is prepared. Specifically, a container 3 is prepared in which the diameter of the throttle hole 3a is changed so that the value of the coefficient of thermal expansion of the corrected sample approaches the target value as compared with the sample. For example, if the value of the coefficient of thermal expansion is negative, a correction container having a correction throttle hole whose diameter is increased in order to increase the amount of the resin base material 4 to be included in the bundle of reinforcing fibers is prepared. A corrected sample is prepared in the same manner.
(6) The coefficient of thermal expansion of the corrected sample is measured.
The coefficient of thermal expansion of the corrected sample is performed using, for example, the above-described measuring apparatus and compared with the target value. And when a measured value is compared with a target value and the difference is small enough, it moves to this process mentioned later and creates grid structure 2.
[0037]
(7) If the measured value of the coefficient of thermal expansion of the corrected sample is not sufficiently small compared to the target value, the measured value of the coefficient of thermal expansion of the corrected sample is the target in the above steps (5) to (6). The diameter of the corrected throttle hole at this time is obtained, and the corrected container having the corrected throttle hole of this diameter is adopted as the container 3 used in this process when the grid structure 2 is actually manufactured.
Here, the measured value of the coefficient of thermal expansion of the sample is actually 0 ± 2 × 10^-8The operation was repeated until it reached / ° C.
[0038]
The volume content of the carbon fiber in the CFRP could be adjusted by the work by the above thermal expansion coefficient adjustment process, and therefore the thermal strain between the reinforcing fiber and the resin base material could be balanced. .
[0039]
2. This process
Using a correction container having a correction throttle hole having a diameter of a size obtained by the thermal expansion coefficient adjustment step, a reinforcing fiber bundle is introduced into the correction container filled with the resin base material 4 to form the resin base material 4. The unit reinforcing fiber bundle 2a is produced by passing through and pulling out the reinforcing fiber bundle from the corrected throttle hole. A reinforcing fiber bundle group 2b in which the unit reinforcing fiber bundles 2a are arranged in parallel with a certain interval, and a reinforcing fiber bundle group in which the unit reinforcing fiber bundles 2a are arranged in parallel with a certain interval in a direction orthogonal to the unit reinforcing fiber bundle 2a. 2c are alternately stacked to produce a grid-like grid structure 2.
[0040]
When the coefficient of thermal expansion of the entire structure of the grid structure 2 manufactured by the above method was measured, 0 ± 5 × 10^-8The value was within the range of / ° C.
[0041]
As described above, according to the second embodiment, the value of the coefficient of thermal expansion is 0 ± 1 × 10.^-7Since it is in the range of / ° C., an effect that it can be applied to an optical apparatus such as an optical apparatus that requires high thermal dimensional stability is obtained.
Further, according to the second embodiment, after the thermal expansion coefficient adjustment process, the thermal expansion coefficient of the bundle of reinforcing fibers that are intermediate materials of the FRP constituting the grid structure 2 is finely adjusted, and then the process proceeds to this process. Since the grid structure is manufactured, an effect that the coefficient of thermal expansion can be adjusted with higher accuracy as compared with the conventional method can be obtained.
[0042]
Embodiment 3 FIG.
Next, a grid structure according to Embodiment 3 of the present invention will be described. The grid structure of the third embodiment is made of CFRP (FRP) including two different types of carbon fibers (reinforcing fibers), and the overall coefficient of thermal expansion is 0 ± 1 × 10.^-7It is a grid structure within the range of / ° C.
[0043]
Two different carbon fibers included in the grid structure are XN-80A (Nippon Graphite Fiber) and M40J (Toray). Moreover, cyanate ester resin RS-3 (made by YLA company) was used as a resin base material. XN-80A is a pitch-based carbon fiber, and the coefficient of thermal expansion in the direction in which the fiber runs is −1.4 × 10.^-6/ ° C. and the elastic modulus is 785 GPa. M40J is a PAN-based carbon fiber, and the coefficient of thermal expansion in the direction in which the fiber runs is −1.2 × 10.^-6/ ° C. and the elastic modulus is 378 GPa. The thermal expansion coefficient of RS-3 is 60 × 10^-6/ ° C. and the elastic modulus is 3 GPa.
[0044]
Using the above-described two types of carbon fibers and resin base material, for example, the grid structure 1 was manufactured by the grid structure manufacturing method of Embodiment 1, and the overall thermal expansion coefficient was measured.^-7The value was within the range of / ° C. Further, when a mechanical property test (a tensile and compression test) was performed, an improvement in rigidity was confirmed as compared with the grid structure 1 of the first embodiment.
[0045]
As described above, according to the grid structure of the third embodiment, the value of the coefficient of thermal expansion is 0 ± 1 × 10.^-7Since it is within the range of / ° C., the same effect as in the first embodiment can be obtained.
Moreover, according to the grid structure of Embodiment 3, since it consists of two types of carbon fibers having different coefficients of thermal expansion and synthesis and a resin base material, various adjustments can be made while adjusting the coefficient of thermal expansion to a desired value. It is possible to realize a structure having an elastic modulus, and an effect that the degree of freedom in designing the structure can be increased is obtained.
[0046]
In addition, although two types of carbon fibers, pitch-based carbon fiber and PAN-based carbon fiber, are combined here, the same effect can be obtained by using other fibers having a low coefficient of thermal expansion such as aramid fiber. Further, any of these fibers may be combined, and an optimal combination of fibers can be adopted as long as two or more types are combined.
Moreover, although the example applied to the grid structure 1 of Embodiment 1 was shown here, it can also be applied to the grid structure 2 of Embodiment 2.
Further, the present invention can be applied not only to the grid structure in the form of a lattice but also to grid structures having other shapes manufactured by the method for manufacturing the grid structure shown in the first and second embodiments.
[0047]
Embodiment 4 FIG.
5A and 5B are explanatory views of a grid structure according to Embodiment 4 of the present invention. FIG. 5A is a schematic exploded perspective view of the grid structure, and FIG. 5B is a tube 1a in the grid structure 1. It is sectional drawing cut | disconnected in the direction orthogonal to a wall surface in one row in which was arranged. In the figure, reference numeral 11 denotes a grid structure provided with a skin 11a described later. 11 a is a skin that covers one side surface of the grid structure 1 and has the same thermal expansion coefficient as the grid structure 1.
As already described, the coefficient of thermal expansion of the grid structure 1 is 0 ± 1 × 10 6 according to the manufacturing method of the grid structure 1 of the first embodiment.^-7It is possible to adjust within the range of / ° C. Moreover, the thermal expansion coefficient of the FRP board used as an outer skin is 1 * 10 by manufacture by various generally known methods.^-7Since it can be adjusted with an accuracy of / ° C., the value of the coefficient of thermal expansion of the entire grid structure 11 is 0 ± 1 × 10^-7/ ° C.
[0048]
As described above, according to the grid structure 11 of the fourth embodiment, the value of the coefficient of thermal expansion of the entire structure is 0 ± 1 × 10.^-7Since it is in the range of / ° C., an effect that it can be applied to an optical apparatus such as an optical apparatus that requires high thermal dimensional stability is obtained.
In addition, since the surface of the grid structure 1 is covered with the skin 11a, the grid structure 1 is reinforced, and the strength and rigidity of the entire structure are improved. In addition, the skin 11a is mounted with a reflecting mirror and equipment. It can be used as a surface, and an effect that the range of use is widened can be obtained.
[0049]
In the fourth embodiment, an example in which the skin 11a is provided only on one side of the grid structure 1 is shown, but a sandwich structure that covers both side surfaces may be used depending on the purpose of use.
In addition, although the grid structure 11 is shown as an example in which the grid structure 1 is covered with the skin 11a, the grid structure 11 can be applied to the grid structure 2. The present invention can also be applied to grid structures having other shapes manufactured by the method for manufacturing a grid structure shown in Embodiment Mode 1 and Embodiment Mode 2.
[0050]
Embodiment 5 FIG.
6A and 6B are explanatory views of a grid structure according to Embodiment 5 of the present invention. FIG. 6A is a schematic exploded perspective view of the grid structure, and FIG. 6B is a tube 1a in the grid structure 1. It is sectional drawing cut | disconnected in the direction orthogonal to a wall surface in one row in which was arranged. In the figure, reference numeral 21 denotes a grid structure provided with skins 21a, which will be described later, covering both side surfaces of the grid structure 1. 21a is an outer skin that covers both side surfaces of the grid structure 1 and balances the thermal strain between the grid structure 1 and 21a.
[0051]
The grid structure 21 is adjusted so as to balance the thermal strain generated in the grid structure 1 when a temperature change occurs and the thermal strain generated in the skin 21a. Specifically, for example, the thermal strains of both are balanced by the following methods i) to iii).
i) The grid structure 1 is manufactured by the grid structure manufacturing method of the first embodiment, and the coefficient of thermal expansion and rigidity between the grid structure 1 and the skin 21a are adjusted.
ii) Adjust the thickness of the grid structure 1 by machining.
iii) Using a plurality of methods from the above methods i) and ii), any one of the coefficient of thermal expansion, rigidity and thickness of the grid structure, or two of them, or both of them are adjusted.
[0052]
Hereinafter, an example of a method for balancing the thermal strain between the grid structure 1 and the skin 21a will be described.
For example, it is assumed that XN-80A (manufactured by Nippon Graphite Fiber) is used as the reinforcing fiber of the grid structure 1, M40J (manufactured by Toray) is used as the reinforcing fiber of the skin 21a, and the cyanate ester resin EX1515 is used as the resin base material. If the volume content of the reinforcing fibers of both the grid structure 1 and the skin 21a is about 60%, the value of the thermal expansion coefficient of the grid structure 1 is negative, and the value of the thermal expansion coefficient of the skin 21a is positive.
Therefore, the thickness of the grid structure 1 and the value of the coefficient of thermal expansion are adjusted by the method for manufacturing the grid structure of the first embodiment. Thereafter, the completed grid structure 1 and the skin 21 a are bonded together to produce the grid structure 21.
When the coefficient of thermal expansion of the entire grid structure 21 manufactured by such a method was measured, 0 ± 1 × 10^-7It was confirmed to be within the range of / ° C.
[0053]
As described above, according to the grid structure 21 of the fifth embodiment, the value of the coefficient of thermal expansion of the entire structure is 0 ± 1 × 10.^-7Within the range of / ° C. Moreover, according to the grid structure 21, the surface of the grid structure 1 is covered with the skin 21a. Therefore, the same effect as in the fourth embodiment can be obtained.
[0054]
In the fifth embodiment, an example is shown in which the skin 21a has a sandwich structure that covers both surfaces of the grid structure 1, but the skin 21a may be provided only on one side depending on the purpose.
In addition, the grid structure 21 is shown as an example in which the grid structure 1 is covered with the skin 21a. However, the grid structure 21 can also be applied to the grid structure 2 by the method for manufacturing the grid structure shown in the first and second embodiments. It can also be applied to other shaped grid structures.
[0055]
Embodiment 6 FIG.
7A and 7B are explanatory views of a grid structure according to Embodiment 6 of the present invention. FIG. 7A is a schematic exploded perspective view of the grid structure, and FIG. It is sectional drawing cut in the direction orthogonal to a wall surface in one row with which 1a was arranged. In the figure, 31 is a grid structure provided with a skin 31a described later and a metal coating layer 31b covering the skin 31a. 31a is a skin covering both surfaces of the grid structure 1, and 31b is a metal coating layer covering each of the skin 31a.
[0056]
The grid structure 31 is adjusted so that the thermal strain generated in the grid structure 1 when the temperature change occurs, the thermal strain generated in the skin 31a, and the thermal strain generated in the metal coating layer 31b can be balanced. Specifically, for example, the thermal strains of the three parties are balanced by the following methods a) to d).
A) The grid structure 1 is manufactured by the grid structure manufacturing method according to the first embodiment, and the coefficient of thermal expansion and rigidity between the grid structure 1 and the skin 31a are adjusted.
B) Adjust the thickness of the grid structure 1 by machining.
C) The thickness of the metal coating layer 31b is adjusted by machining or chemical treatment.
D) Any one of the thermal expansion coefficient, rigidity, thickness, thickness of the metal coating layer of the grid structure 31 or any of two or more of the above-mentioned methods a) to c) using a plurality of methods. Or adjust both.
[0057]
Here, XN-80A (manufactured by Nippon Graphite Fiber) is used as the reinforcing fiber of the grid structure 1, M40J (manufactured by Toray) is used as the reinforcing fiber of the skin 31a, cyanate ester resin EX1515 is used as the resin base material, and metal coating is performed. Nickel was used as the material of the layer 31b, and the thermal distortion of the three parties was adjusted using the method described above. Thereafter, the completed grid structure 1 and the skin 31 a provided with the metal coating layer 31 b are bonded together to produce the grid structure 31.
When the coefficient of thermal expansion of the entire grid structure 31 produced by such a method was measured, 0 ± 1 × 10^-7It was within the range of / ° C., and it was confirmed that the optical reflector could be used sufficiently.
[0058]
As described above, according to the grid structure 31 of the sixth embodiment, the value of the coefficient of thermal expansion of the entire structure is 0 ± 1 × 10.^-7Within the range of / ° C. Therefore, the same effect as in the first embodiment can be obtained.
Moreover, the surface of the grid structure 1 is covered with the skin 31a provided with the metal coating layer 31b. Therefore, the same effect as in the fourth embodiment can be obtained.
Moreover, since the surface of the skin 31a is covered with the metal coating layer 31b, it can be used as an optical reflecting mirror excellent in thermal dimensional stability.
[0059]
In the sixth embodiment, an example in which the skin 31a and the metal coating layer 31b have a sandwich structure that covers both surfaces of the grid structure 1 is shown. However, the skin 31a and the metal coating layer 31b may be provided only on one side depending on the purpose. .
Further, the grid structure 31 is shown as an example in which the grid structure 1 is covered with the skin 31 and the metal coating layer 31b. However, the case where the grid structure 31 is covered with the grid structure 2 is also shown in the first and second embodiments. The present invention can also be applied to grid structures having other shapes manufactured by the grid structure manufacturing method.
[0060]
In the first embodiment and the third to sixth embodiments, the shape of the tube (unit structure) 1a has been described for the case where the cross-sectional shape is a quadrangle. However, the shape of the unit structure is not limited to this, and the same shape. Any shape that can accumulate a plurality of unit structures may be used.
[0061]
【The invention's effect】
  As described above, according to the present invention, the fiber-reinforced plastic is constituted., Reinforcing fiber with a negative coefficient of thermal expansion,Since the thermal strain between the resin base material and the resin base material is balanced, the overall coefficient of thermal expansion is 0 ± 1 × 10.^-7Within the range of / ℃Since a plurality of cylindrical unit structures are accumulated to form one net-like structure,There is an effect that it can be applied to an optical apparatus such as an optical apparatus that requires high thermal dimensional stability.
[0062]
According to this invention, a) a test piece is prepared by laminating a prepreg impregnated with a semi-cured resin base material in a reinforcing fiber, and the coefficient of thermal expansion of this test piece is measured. b) In order to bring it closer to the desired value than the measured value of the coefficient of thermal expansion in the previous step, a modified test piece was prepared by laminating the prepreg while sandwiching a semi-cured resin film as appropriate. The expansion coefficient is measured. c) Thermal expansion coefficient adjustment step including steps a) to c), in which the step b) is repeated until the desired value is reached while changing the thickness and the number of layers of the resin film, and the desired value is obtained. The grid structure manufacturing method is configured to include the present step of forming a mesh-like grid structure formed by integrating a plurality of cylindrical unit structures formed using the corrected test piece at the time of Compared with the method, the coefficient of thermal expansion can be adjusted with higher accuracy, and the value of the overall coefficient of thermal expansion is stabilized to 0 ± 1 × 10^-7There is an effect that it can be within the range of / ° C.
[0063]
According to the present invention, A) A reinforcing fiber bundle in which reinforcing fibers are bundled is put into a container filled with a liquid resin base material and provided with a throttle hole at the bottom, and the reinforcing fiber bundle is drawn out from the throttle hole. Thus, a sample in which the resin base material is immersed in a reinforcing fiber bundle is prepared, and the thermal expansion coefficient of the sample is measured. B) In order to bring it closer to a desired value than the measured value of the coefficient of thermal expansion in the previous process, the liquid resin base material is filled, and the diameter of the diameter of the previous process container is changed. By introducing the reinforcing fiber bundle into the correction container and pulling out the reinforcing fiber bundle from the correction restriction hole, a correction sample is produced in which the amount of liquid resin base material attached is changed from the previous process, and the thermal expansion of this correction sample is made. Measure the rate. C) Reinforcing fiber using the thermal expansion coefficient adjusting process including the processes of A) to C), that is, repeating the process B) until the desired value is reached, and the correction container when the desired value is reached. A large number of unit reinforcing fiber bundles are produced by immersing the resin base material in the bundle, and the first fiber bundle group in which the unit reinforcing fiber bundles are arranged in parallel at a predetermined interval, and the unit reinforcing fiber bundle are A grid-like grid structure is formed by alternately stacking second fiber bundle groups arranged in parallel at regular intervals in a direction having a constant angle with respect to one fiber bundle group. Therefore, the thermal expansion coefficient can be adjusted with higher accuracy than the conventional method, and the value of the overall thermal expansion coefficient can be stabilized to 0 ± 1. × 10^-7There is an effect that it can be within the range of / ° C.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view for explaining a configuration of a grid structure according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure of a method for manufacturing a grid structure according to the first embodiment of the present invention.
FIG. 3 is a schematic exploded perspective view for explaining a configuration of a grid structure according to a second embodiment of the present invention.
FIG. 4 is a schematic diagram for explaining a method of manufacturing a grid structure according to a second embodiment of the present invention.
FIG. 5 is an explanatory diagram of a grid structure according to a fourth embodiment of the present invention.
FIG. 6 is an explanatory diagram of a grid structure according to a fifth embodiment of the present invention.
FIG. 7 is an explanatory diagram of a grid structure according to a sixth embodiment of the present invention.
FIG. 8 is a schematic explanatory diagram showing a configuration of a conventional grid structure.
[Explanation of symbols]
1, 2, 11, 21, 31 Grid structure, 1a tube (unit structure), 2a unit reinforcing fiber bundle, 2b first reinforcing fiber bundle group, 2c second reinforcing fiber bundle group, 3 container, 3a throttle hole, 4 resin base material, 11a, 21a, 31a skin, 31b metal coating layer.

Claims (8)

In the grid structure made of fiber reinforced plastic,
The overall thermal expansion coefficient is 0 ± 1 × 10 ⁻⁷ / ° C. because the thermal strain between the reinforcing fiber having a negative coefficient of thermal expansion constituting the fiber reinforced plastic and the resin base material is balanced. Is in range ,
A grid structure characterized in that a plurality of cylindrical unit structures are integrated to form one net-like structure.   A first fiber bundle group in which unit reinforcing fiber bundles impregnated with a resin base material and bundled with reinforcing fibers are arranged in parallel at regular intervals; and the unit reinforcing fiber bundle is the first fiber bundle. 2. The grid structure according to claim 1, wherein the second fiber bundle groups arranged in parallel with a certain interval in a direction having a certain angle with respect to the group are alternately stacked. .   The grid structure according to claim 1, wherein the reinforcing fibers are a combination of two or more types of reinforcing fibers having different coefficients of thermal expansion and rigidity.   The grid structure according to claim 1, further comprising a skin covering one or both surfaces of the grid structure and having the same coefficient of thermal expansion as the grid structure.   The grid structure according to claim 1, further comprising a skin covering one or both surfaces of the grid structure and having a thermal strain balanced with the grid structure. The grid structure according to claim 4 or 5 , further comprising a metal coating layer on the surface of the skin, in which a thermal strain between the skin and the skin is balanced. a) preparing a test piece obtained by laminating a prepreg impregnated with a semi-cured resin base material in a reinforcing fiber, and measuring a coefficient of thermal expansion of the test piece;
b) In order to bring it closer to the desired value than the measured value of the coefficient of thermal expansion in the previous step, a modified test piece is prepared by laminating the prepreg while appropriately sandwiching a semi-cured resin film, and the heat of the corrected test piece A step of measuring the expansion rate;
c) a coefficient of thermal expansion adjustment including a step of repeating the step b) until the desired value is reached while changing the thickness and the number of layers of the resin film;
A grid structure including a step of forming a net-like grid structure in which a plurality of cylindrical unit structures formed by using the modified test piece are accumulated when the desired value is reached. Manufacturing method. A) A reinforcing fiber bundle in which reinforcing fibers are bundled is put into a container filled with a liquid resin base material and provided with a throttle hole at the bottom, and the reinforcing fiber bundle is drawn out from the throttle hole, whereby the reinforcing fiber bundle is extracted. Producing a sample in which the resin base material is immersed in a bundle, and measuring the coefficient of thermal expansion of the sample;
B) In order to bring it closer to a desired value than the measured value of the coefficient of thermal expansion in the previous process, the liquid resin base material is filled, and the diameter of the diameter of the previous process container is changed. By introducing the reinforcing fiber bundle into a correction container and pulling out the reinforcing fiber bundle from the correction throttle hole, a correction sample in which the amount of the liquid resin base material attached is changed from that in the previous process is prepared, and the correction sample Measuring the coefficient of thermal expansion of
C) Thermal expansion coefficient adjustment step including the step of repeating the step B) until the desired value is reached,
A large number of unit reinforcing fiber bundles are produced by immersing the resin base material in the reinforcing fiber bundles using the correction container when the desired value is reached, and the unit reinforcing fiber bundles are spaced at regular intervals. The first fiber bundle group arranged in parallel and the unit reinforcing fiber bundle are arranged in parallel with a certain interval in a direction having a certain angle with respect to the first fiber bundle group. A method for producing a grid structure, comprising the step of forming a net-like grid structure by alternately stacking two fiber bundle groups.

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