JP3650880B2

JP3650880B2 - Method for manufacturing flat roof tiles

Info

Publication number: JP3650880B2
Application number: JP22521799A
Authority: JP
Inventors: 杉浦伸二
Original assignee: 高浜工業株式会社
Priority date: 1999-08-09
Filing date: 1999-08-09
Publication date: 2005-05-25
Anticipated expiration: 2019-08-09
Also published as: JP2001047417A

Description

【０００１】
【発明が属する技術分野】
この発明は、平板瓦の製造方法に関し、とくに乾燥や焼成時に発生しがちな歪や亀裂を抑制する平板瓦の製造方法に関する。
【０００２】
【従来の技術】
粘土瓦のうち、平板瓦（Ｆ形粘土かわら、日本工業規格５２０８Ａ）は洋風住宅の普及に伴って需要が近年増大している。
例えば、図７に示されるように一般的な平板瓦Ｈは板状の形態であって、主に瓦本体部Ａ、アンダーラップ部Ｂ、オーバーラップ部Ｃ、接続部Ｄから構成されている。
【０００３】
アンダーラップ部Ｂは瓦本体部Ａの一側に長さ方向に設けられており、瓦本体部Ａとアンダーラップ部Ｂとの境には、瓦本体部Ａに対して直角方向に設けられた接続部Ｄが介設されているので、アンダーラップ部Ｂは瓦本体部Ａに対して段差状となっている。
一方、オーバーラップ部Ｃは瓦本体部Ａの他側に長さ方向に設けられている（図７を参照）。
【０００４】
平板瓦Ｈを屋根に葺いた際に、平板瓦Ｈのアンダーラップ部Ｂは一側に隣接する別の平板瓦Ｈのオーバーラップ部Ｃの下方に位置し、一方、オーバーラップ部Ｃは他側に隣接するさらに別の平板瓦Ｈのアンダーラップ部Ｂの上方に位置し、瓦本体部Ａの表面は両側に隣接する平板瓦Ｈの瓦本体部Ａの表面と同じ高さになり、幅方向に平坦状の連続面が形成される。
【０００５】
平板瓦Ｈは、通常の和形瓦（Ｊ形粘土かわら）と同様に水分を含んだ粘土原料を連続的に押出成形し、所定の寸法に切断された押出成形体Ｅを加圧することにより成形されていた（図８を参照）。
【０００６】
そして、加圧成形により得られた成形素地Ｈ（完成品である平板瓦Ｈと形態が相似形であるため共通の符号とする）に対して乾燥、施釉や焼成などの処理を施して完成品である平板瓦Ｈが得られる。
【０００７】
ただし、平板瓦Ｈはその形態がほぼ板状であるため、切断された押出成形体Ｅは、平板瓦Ｈの形態に対応する成形型Ｇを備えたプレス成形機などにより加圧成形されていた（図９を参照）。
【０００８】
ところが、板状の押出成形体Ｅの状態で加圧成形して、瓦本体部Ａとアンダーラップ部Ｂとの境界を段差状に成形するものの、加圧成形により得られた成形素地Ｈにおける瓦本体部Ａとアンダーラップ部Ｂの境界付近にあっては、水平方向からほぼ直角方向に向かい再び水平方向に向かう形態であることから、成形素地Ｈの他の部位と比較して原料が成形型Ｇによる成形圧力の抵抗を受け易く、成形型Ｇの内部において原料が十分に成形型Ｇ内に行き亘らないおそれがあった。
【０００９】
とくに、成形素地Ｈにおける瓦本体部Ａとアンダーラップ部Ｂの境界付近である接続部Ｄ付近では、原料の巻き込みＰあるいは充填不足Ｑを生じ、外観上、瑕疵のある平板瓦となり、商品価値を低下させるほか、製品としての強度不足を招くという問題があった（図９を参照）。
【００１０】
さらに、成形素地Ｈにおける接続部Ｄ付近にあっては、加圧成形の際に段差状の形態により起因する原料の密度の較差による相違が生じ、この原料の密度の相違は乾燥や焼成時における瓦本体部Ａとアンダーラップ部Ｂとの境界付近の歪や亀裂を助長させる原因となっていた。
【００１１】
また、瓦本体部Ａとアンダーラップ部Ｂとの境界を段差状に成形するため、両者Ａ、Ｂの境の接続部Ｄは成形素地Ｈの他の部位と比較して加圧成形による原料の粘土粒子の配向性が著しく異なることになる。
その結果、成形素地Ｈにおける粘土粒子の配向性の著しい相違は、乾燥や焼成時における瓦本体部Ａとアンダーラップ部Ｂとの境界付近の歪や亀裂の原因となっていた。
【００１２】
【発明が解決しようとする課題】
この発明が解決しようとする課題は、従来の平板瓦の製造においては、加圧成形の際に、成形素地の瓦本体部とアンダーラップ部の境界付近おいて、成形素地が他の部位と比較して原料の密度が相違することにより、乾燥や焼成時に歪や亀裂を生じる点のほか、成形素地の瓦本体部とアンダーラップ部との境界付近において、成形素地が他の部位と比較して粘土粒子の配向性の著しい相違が生じることにより、原料の密度の相違と相まって乾燥や焼成時に歪や亀裂をさらに促す点にある。
【００１３】
この発明の目的は、平板瓦の加圧成形の際に、成形素地の瓦本体部とアンダーラップ部との境界付近における原料の密度の差を緩和するほか、粘土粒子の配向性の著しい相違を発生させず、乾燥や焼成時において瓦本体部とアンダーラップ部の境界付近に発生する歪や亀裂を抑制する平板瓦の製造方法の提供にある。
【００１４】
【問題を解決するための手段および作用効果】
上記の目的を達成するため、請求項１記載の平板瓦の製造方法は、粘土原料を押出成形することにより板状の押出成形体を得、板状の押出成形体を加圧成形して成形素地を得る平板瓦の製造方法において、押出成形体を加圧成形することにより、成形素地の瓦本体部とアンダーラップ部との間に接続部を設けるとともに、接続部をアンダーラップ部から瓦本体部に向けて３０〜６０度に傾斜させてなることを特徴とするものである。
【００１５】
したがって、請求項１記載の平板瓦の製造方法は、押出成形体を加圧成形することにより、成形素地の瓦本体部とアンダーラップ部との間に接続部を設けるとともに、アンダーラップ部から瓦本体部に向けて３０〜６０度に傾斜させた接続部を設けたから、加圧成形における原料が成形型内に行き亘り易くなり、成形素地の本体部とアンダーラップ部との境界である接続部における原料の密度は、他の部位と比較して相違が緩和され、乾燥や焼成時において成形素地の本体部とアンダーラップ部との境界である接続部に生じがちな歪や亀裂が抑制される。
【００１６】
また、押出成形体を加圧成形することにより、成形素地の本体部とアンダーラップ部との境界である接続部は３０〜６０度に傾斜される。
したがって、成形素地の本体部とアンダーラップ部との境界である接続部における粘土粒子の配向性は、原料の密度の相違の緩和と相俟って他の部位との相違が抑制され、乾燥や焼成時において瓦本体部とアンダーラップ部の境界付近に生じがちな歪や亀裂がさらに抑制される。
【００１７】
請求項２記載の平板瓦の製造方法は、請求項１記載の平板瓦の製造方法において、押出成形体に瓦本体予定部、アンダーラップ予定部および接続予定部を設け、押出成形体の断面形態を、アンダーラップ予定部から接続予定部、瓦本体予定部に亘って、成形素地の幅方向の断面形態と略対応させることを特徴とするものである。
【００１８】
したがって、請求項２記載の平板瓦の製造方法は、請求項１記載の乾燥方法の場合と同様の作用を奏するが、加圧成形に先立って押出成形体に瓦本体予定部、アンダーラップ予定部および接続予定部を設けるとともに、押出成形体の断面形態を、アンダーラップ予定部から接続予定部、瓦本体予定部に亘って、成形素地の幅方向の断面形態と略対応させるので、加圧成形における原料が成形型内により円滑に行き亘り易くなり、成形素地の瓦本体部とアンダーラップ部との境界である接続部における原料の密度は、他の部位との相違がより一層緩和され、乾燥や焼成時において成形素地の瓦本体部とアンダーラップ部との境界である接続部に生じがちな歪や亀裂が飛躍的に抑制される。
【００１９】
その上、加圧成形の際、成形素地の瓦本体部とアンダーラップ部との境界である接続部における粘土粒子の配向性は、他の部位との相違がより一層緩和され、原料の密度の相違のより一層の緩和と相俟って、乾燥や焼成時において瓦本体部とアンダーラップ部の境界付近に生じがちな歪や亀裂がさらに抑制される。
【００２０】
【発明の実施の形態】
この発明の実施の形態に係る平板瓦の製造方法について図面を参照して説明する。
図１はこの発明の実施の形態に係る平板瓦の製造方法における成形素地を正面からみた断面図、図２は加圧成形前の押出成形体を正面からみた断面図、図３は加圧成形後における成形素地を正面からみた断面図、図４は成形素地の原料の密度の状態と粘土粒子の配向性を示す要部の拡大図、図５はこの実施の形態に係る平板瓦の成形素地の斜視図、図６は別の実施の形態に係る押出成形体を正面からみた断面図、図７は従来の技術に係る平板瓦の斜視図、図８は従来の技術に係る押出成形体の斜視図、図９は従来の技術における加圧成形時の成形素地の密度の状態と配向性を示す要部の断面図である。
【００２１】
（押出成形体について）
押出成形体１０は押出成形機により得られるものであるが、後工程である加圧成形のために所定の寸法に切断されている。
押出成形体１０はほぼ板状であって、瓦本体予定部１２およびアンダーラップ予定部１４、接続予定部１６、オーバーラップ予定部１８から構成されている（図２を参照）。
そして、押出成形体１０が加圧成形されることにより後述する成形素地３０となる。
【００２２】
瓦本体予定部１２は、成形素地３０における瓦本体部３２に対応する部位であり、押出成形体１０の大部分を占めている。
そして、瓦本体予定部１２は水平状態にあり、瓦本体予定部１２の一側からやや下方へ向けて傾斜された接続予定部１６が設けられている（図２を参照）。
【００２３】
接続予定部１６は成形素地３０の接続部３６に対応する部位であり、この実施の形態における接続予定部１６はアンダーラップ予定部１４へ向けて下方に３５度に傾斜されている。
【００２４】
アンダーラップ予定部１４は、接続予定部１６の一側から水平方向へ向けて設けられており、成形素地３０のアンダーラップ部３４に対応する部位である。
他方、瓦本体予定部１２の他側にはオーバーラップ予定部１８が設けられ、成形素地３０のオーバーラップ部３８に対応するものである。
【００２５】
また、この実施の形態においては、成形素地３０の裏面に設けられる補強リブ４２に対応する膨出部２２が瓦本体予定部１２に所定の間隔を保って３個所に設けられている。
【００２６】
この実施の形態に係る押出成形体１０は上記のように、断面において一側から他側へ向けて、アンダーラップ予定部１４、接続予定部１６、瓦本体予定部１２、オーバーラップ予定部１８という順に構成される。
【００２７】
そして、水平状態にある部位はオーバーラップ予定部１８、瓦本体予定部１２およびアンダーラップ予定部１４であり、接続予定部１６は傾斜されている。
押出成形体１０の断面において、瓦本体予定部１２およびオーバーラップ予定部１８のほぼ中心を通過する線を中心線Ｍとし、アンダーラップ予定部１４のほぼ中心を通過する線を中心線Ｎとし、接続予定部１６のほぼ中心を通過する線を中心線Ｙとすると、中心線Ｍ、Ｎは互いに平行であって、中心線Ｙ、Ｎにより形成される鋭角が３５度となっている。
【００２８】
押出成形体１０の接続予定部１６を傾斜させる理由は後述する加圧成形の際に、成形素地３０における瓦本体部３２の一側、接続部３６、接続部３６とアンダーラップ部３４との境界、すなわち瓦本体部３２とアンダーラップ部３４との境界付近において、加圧成形に伴う粘土粒子の配向性の著しい相違の発生を抑制するためである。
【００２９】
つまり、押出成形体１０におけるオーバーラップ予定部１８、瓦本体予定部１２の大部分およびアンダーラップ予定部１４は水平状態にあり、加圧成形により成形素地３０に成形されても基本的に水平状態にあるため粒子の配向性の変化は小さい。
【００３０】
一方、押出成形体１０の接続予定部１６付近、すなわち瓦本体予定部１２とアンダーラップ予定部１４との境界付近は、加圧成形により成形素地３０においてほぼ直角の段差状に成形されると、水平状態にある瓦本体予定部１２とアンダーラップ予定部１４、オーバーラップ予定部１８の形状の変化と比較してその変化が大きく、瓦本体予定部１２とアンダーラップ予定部１４との境界付近における粒子の配向性は著しく変化することになる。
【００３１】
したがって、粘土粒子の配向性の変化の大きい部位と、小さい部位が成形素地３０に生ずることになり、成形素地３０における粒子の配向性が部位により著しく相違することになる。
この粘土粒子の配向性の著しい相違が、乾燥や焼成時において成形素地３０の歪や亀裂を生じる原因となり、その粘土粒子の配向性の変化が大きい部位に集中して発生しやすい。
【００３２】
この実施の形態においては、加圧成形の際に瓦本体予定部１２とアンダーラップ予定部１４との境界付近における粒子の配向性の変化を抑制し、成形素地３０における粘土粒子の配向性が部位により著しく相違することを抑制するために、押出成形体１０の瓦本体予定部１２の一側から接続予定部１６とアンダーラップ予定部１４について、後述する成形素地３０における瓦本体部３２の一側から接続部３６とアンダーラップ部３４との境界に至る断面形態に略対応させている。
【００３３】
とくに、この実施の形態においては、押出成形体１０の接続予定部１６の傾斜角度が約３５度であり、加圧成形により押出成形体１０から成形素地３０に成形されても、接続予定部１６の３５度から接続部３６の４５度への変化であり、その差が１０度となる（図１および図２を参照）。
【００３４】
発明者の試験によれば、加圧成形による接続予定部１６の傾斜角度の変化が２０度以内であれば、乾燥や焼成時における歪や亀裂に対してより効果的に抑制されることが確認されており、成形素地３０における粘土粒子の配向性および原料密度の著しい相違が抑制されることにほかならない。
【００３５】
したがって、成形素地３０における接続部３６の傾斜角度が４５度であるこの実施の形態の場合では、接続予定部１６の傾斜角度は２５〜４５度の範囲で自由に設定すればよい。
【００３６】
なお、成形素地３０における接続部３６の傾斜角度を３０〜６０度の範囲で設定する場合、押出成形体１０における接続予定部１６の傾斜角度は、接続部３６と接続予定部１６の角度の差が２０度以内であればよいから、最小で１０度、最大で５０度となるが、成形素地３０の幅方向の断面形態と略対応する範囲にある。
【００３７】
瓦本体予定部１２の一側から接続予定部１６、アンダーラップ予定部１４を連続して設け、接続予定部１６の傾斜角度が約３５度となるように押出成形することにより、押出成形により得られた押出成形体１０の幅方向の断面形態が成形素地３０の幅方向の断面形態に略対応することから、加圧成形において成形型に対する原料の抵抗が低減され、原料が成形型内に十分行き亘りやすくなる。
【００３８】
したがって、成形素地３０における瓦本体部３２とアンダーラップ部３４との境界付近における原料の密度は、他の部位と比較して大きく相違することがなく、先に述べた粘土粒子の配向性の著しい相違を抑制する点と相俟って、原料の密度の相違による乾燥や焼成時の歪および亀裂を抑制することができる。
【００３９】
なお、この実施の形態では、歪や亀裂の抑制に対してより好ましい成形素地３０を得るために、押出成形体１０に傾斜された接続予定部１６を設けたが、傾斜された接続予定部１６を設けず従来と同様に単に板状の押出成形体を採用しても、加圧成形により得られる成形素地の原料の密度の相違、配向性の相違は抑制されることはいうまでもない。
【００４０】
（成形素地について）
この実施の形態に係る成形素地３０は、瓦本体部３２、アンダーラップ部３４、接続部３６、オーバーラップ部３８、補強リブ４２から構成され、形態の上では製品としての平板瓦と異なる点はない。
【００４１】
この実施の形態における成形素地３０は、押出成形体１０を加圧成形することにより得られるものであり、加圧成形の具体的な手段はプレス成形機とプレス成形機に取り付けられた上型４４および下型４６からなる成形型である（図２および図３を参照）。
【００４２】
この実施の形態における成形素地３０は、瓦本体部３２の他側にオーバーラップ部３８が設けられ、一方、瓦本体部３２の裏面には３個の補強リブ４２が設けられ、瓦本体部３２の強度を向上させる工夫が図られている。
そして、アンダーラップ部３４は瓦本体部３２に対して段差状になるように接続部３６を介して設けられている。
アンダーラップ部３４と瓦本体部３２との間に幅方向に４５度に傾斜された接続部３６が設けられている。
【００４３】
この成形素地３０の断面において、瓦本体部３２およびオーバーラップ部３８のほぼ中心を通過する線を中心線ｍとし、アンダーラップ予定部３４の中心を通過する線を中心線ｎとし、接続予定部３６の中心を通過する線を中心線ｘとすると、中心線ｍ、ｎは互いに平行であって、中心線ｘ、ｎにより形成される鋭角が４５度となっている。
【００４４】
この接続部３６は従来と異なって傾斜されているので、加圧成形を受けた接続部３６における粘土粒子の配向性は、他の部位（瓦本体部３２、アンダーラップ部３４、オーバーラップ部３８）と比較して著しく相違することがない。
【００４５】
つまり、瓦本体部３２、アンダーラップ部３４およびオーバーラップ部３８は、押出成形体１０から成形素地３０に成形されるが、基本的に水平状態を維持しており形態の変化が小さい。
【００４６】
ところが、平板瓦としての機能を保つため、アンダーラップ部３４と瓦本体部３２は互いに段差状に設けなければならない。
【００４７】
そこで、接続部３６が４５度に傾斜するように加圧成形されるが、平板瓦の機能が保たれる範囲内で接続部３６を傾斜させ、押出成形体１０から成形素地３０への成形における接続部３６の形態の変化を抑制することを図っている。
接続部３６の形態の変化が抑制されることから、押出成形体１０から成形素地３０への成形において、接続部３６における粘土粒子の配向性の変化が小さくなり、他の部位と比較において粘土粒子の配向性の著しい相違が抑制される（図４を参照）。
【００４８】
したがって、成形素地３０の部位による粘土粒子の配向性の著しい相違が生じないため、乾燥や焼成時における歪や亀裂が抑制される。
【００４９】
また、接続部３６が４５度に傾斜するように加圧成形することにより、成形型に対する原料の抵抗が低減され、原料が成形型内に十分行き亘りやすくなり、成形素地３０における瓦本体部３２とアンダーラップ部３４との境界付近における原料の密度は、他の部位と比較して大きく相違することがなく、先に述べた粘土粒子の配向性の著しい相違を抑制する点と相俟って、原料の密度の相違による乾燥や焼成時の歪および亀裂を抑制することができる（図４を参照）。
【００５０】
なお、この実施の形態においては、最も好ましい例として、押出成形体１０の瓦本体予定部１２、接続予定部１６およびアンダーラップ予定部１４を設け、接続予定部１６の傾斜角度が３５度となるように押出成形し、成形素地３０の瓦本体部３２とアンダーラップ部３４との接続部３６が幅方向に４５度に傾斜されるように、得られた押出成形体１０を加圧成形する例である。
【００５１】
この場合、前記した接続予定部１６を設けるようにした押出成形体１０を得ることと、接続部３６が傾斜されるように押出成形体１０を加圧成形することの相乗効果により、得られた成形素地３０は乾燥や焼成時において歪や亀裂が飛躍的に抑制される。
【００５２】
ただし、成形素地３０の接続部３６については３０〜６０度の範囲の傾斜角度であれば平板瓦の機能を損なうことなく、先に説明した有利性を得ることができる。
【００５３】
次に別の実施の形態に係る押出成形体について説明する。
この実施の形態の押出成形体５０は、成形素地３０の幅方向の断面形態と略対応させたものであり、先に説明した実施の形態と同様に瓦本体予定部５２、アンダーラップ予定部５４、接続予定部５６、オーバーラップ予定部５８および膨出部６２を備えるものであるが、瓦本体予定部５０から接続予定部５６を通じてアンダーラップ予定部５４に至る部位が山状の形態を呈しているものである（図６を参照）。
【００５４】
山状の形態は、瓦本体部５２の本体傾斜部６４と、接続予定部５６の接続傾斜部６６とから構成されている。
そして、本体傾斜部６４の傾斜角度が１５度、接続傾斜部６６の傾斜角度が２５度となっている（図６を参照）。
【００５５】
押出成形体５０の断面において、本体傾斜部６４を除く瓦本体予定部５２、オーバーラップ部５８およびアンダーラップ予定部５４のほぼ中心を通過する線を中心線ａとし、接続予定部５６の中心を通過する線を中心線ｂとし、瓦本体予定部５２における本体傾斜部６４の中心を通過する線を中心線ｃとすると、中心線ａ、ｂにより形成される鋭角が２５度となり、他方中心線ｂ、ｃにより形成される鋭角が１５度となっている。
【００５６】
この実施の形態の押出成形体５０を採用することにより、押出成形体５０の搬送においてコンベアなどの搬送装置が複雑化しないことなど、搬送面における押出成形体５０の取扱いが容易となる利点を有する。
【００５７】
そして、この実施の形態に係る押出成形体５０を加圧成形することにより、先の実施の形態で述べた成形素地３０が得られ、乾燥や焼成時において同様に成形素地３０の歪や亀裂が抑制されることはいうまでもない。
【図面の簡単な説明】
【図１】実施の形態に係る平板瓦の製造方法における成形素地を正面からみた断面図である。
【図２】加圧成形前の押出成形体を正面からみた断面図である。
【図３】加圧成形後における成形素地を正面からみた断面図である。
【図４】成形素地の原料の密度の状態と粘土粒子の配向性を示す要部の拡大図である。
【図５】この実施の形態に係る平板瓦の斜視図である。
【図６】別の実施の形態に係る押出成形体を正面からみた断面図である。
【図７】従来の技術に係る平板瓦の斜視図である。
【図８】従来の技術に係る押出成形体の斜視図である。
【図９】従来の技術における加圧成形時の成形素地の密度の状態と配向性を示す要部の断面図である。
【符号の説明】
１０押出成形体
１２瓦本体予定部
１４アンダーラップ予定部
１６接続予定部
１８オーバーラップ予定部
２２膨出部
３０成形素地
３２瓦本体部
３４アンダーラップ部
３６接続部
３８オーバーラップ部
４２補強リブ
４４上型
４６下型
５０押出成形体
５２瓦本体予定部
５４アンダーラップ予定部
５６接続予定部
５８オーバーラップ予定部
６２膨出部
６４本体傾斜部
６６接続傾斜部
Ａ瓦本体部
Ｂアンダーラップ部
Ｃオーバーラップ部
Ｄ接続部
Ｅ押出成形体
Ｇ成形型
Ｈ平板瓦（成形素地）
Ｐ巻き込み
Ｑ充填不足[0001]
[Technical field to which the invention belongs]
The present invention relates to a method for manufacturing a flat roof tile, and more particularly to a method for manufacturing a flat roof tile that suppresses distortion and cracks that tend to occur during drying and firing.
[0002]
[Prior art]
Among clay tiles, demand for flat roof tiles (F-type clay, Japanese Industrial Standard 5208A) has increased in recent years with the spread of Western-style houses.
For example, as shown in FIG. 7, a general flat roof tile H has a plate-like form, and mainly includes a roof tile main body A, an underlap portion B, an overlap portion C, and a connection portion D.
[0003]
The underlap portion B is provided in the length direction on one side of the roof tile main body A, and is provided in a direction perpendicular to the roof tile main body A at the boundary between the roof tile main body A and the underlap portion B. Since the connecting portion D is interposed, the underlap portion B is stepped with respect to the roof tile main body A.
On the other hand, the overlap part C is provided in the length direction on the other side of the roof tile main part A (see FIG. 7).
[0004]
When the flat tile H is laid on the roof, the underlap portion B of the flat tile H is located below the overlap portion C of another flat tile H adjacent to one side, while the overlap portion C is on the other side. Is located above the underlap portion B of another flat roof tile H adjacent to the roof tile B, and the surface of the roof tile main body A has the same height as the surface of the roof tile main body A of the flat roof tile H adjacent to both sides. A flat continuous surface is formed.
[0005]
The flat roof tile H is formed by continuously extruding a clay raw material containing moisture in the same manner as a normal Japanese roof tile (J-shaped clay tile) and pressurizing an extruded product E cut to a predetermined size. (See FIG. 8).
[0006]
The finished product is then subjected to treatments such as drying, glazing, and firing on the green body H obtained by pressure molding (the shape is similar to the flat roof tile H, which is a finished product). A flat roof tile H is obtained.
[0007]
However, since the shape of the flat roof tile H is substantially plate-shaped, the cut extruded body E was pressure-formed by a press molding machine provided with a forming die G corresponding to the shape of the flat roof tile H. (See FIG. 9).
[0008]
However, although it is pressure-molded in the state of the plate-like extruded molded body E and the boundary between the tile main body part A and the underlap part B is formed in a stepped shape, the tile in the molding base H obtained by pressure molding. In the vicinity of the boundary between the main body part A and the underlap part B, the raw material is formed in a molding die as compared with other parts of the molding substrate H because it is in the form of moving from the horizontal direction to a substantially right angle direction and again to the horizontal direction. G tends to be subjected to resistance to molding pressure due to G, and there is a possibility that the raw material does not sufficiently reach inside the mold G inside the mold G.
[0009]
In particular, in the vicinity of the connecting portion D, which is near the boundary between the tile main body A and the underlap portion B in the molding substrate H, the material P is caught or the filling is insufficient Q, and the appearance is a flat roof tile with a wrinkle. In addition to lowering, there was a problem of inadequate strength as a product (see FIG. 9).
[0010]
Further, in the vicinity of the connecting portion D in the molding substrate H, a difference due to the difference in the density of the raw materials caused by the step-like form occurs during the pressure forming, and the difference in the density of the raw materials is caused during the drying and firing. This was a cause of promoting distortion and cracks near the boundary between the tile main body A and the underlap B.
[0011]
Moreover, in order to form the boundary between the tile main body part A and the underlap part B in a stepped shape, the connecting part D at the boundary between the two A and B is made of the raw material by pressure molding as compared with other parts of the molding substrate H. The orientation of the clay particles will be significantly different.
As a result, the remarkable difference in the orientation of the clay particles in the forming substrate H has caused strain and cracks near the boundary between the tile main body A and the underlap B during drying and firing.
[0012]
[Problems to be solved by the invention]
The problem to be solved by the present invention is that, in the manufacture of conventional flat roof tiles, the molding substrate is compared with other parts in the vicinity of the boundary between the tile main body and the underlap portion of the molding substrate during pressure molding. In addition to the fact that the density of the raw materials is different, distortion and cracks occur during drying and firing, and in the vicinity of the boundary between the tile body and the underlap of the molding substrate, the molding substrate is compared with other parts. Due to the significant difference in the orientation of the clay particles, the difference in the density of the raw materials is combined with the point of further promoting distortion and cracking during drying and firing.
[0013]
The purpose of the present invention is to reduce the difference in the density of raw materials in the vicinity of the boundary between the tile main body and the underlap portion of the forming base during the pressure forming of the flat roof tile, and to make a significant difference in the orientation of the clay particles. An object of the present invention is to provide a method for producing a flat roof tile that suppresses distortion and cracks that occur near the boundary between the roof tile main body and the underlap portion during drying and firing.
[0014]
[Means for solving problems and effects]
In order to achieve the above object, the flat roof tile manufacturing method according to claim 1 obtains a plate-like extruded product by extruding a clay raw material, and press-molds the plate-like extruded product to form it. In the method for producing a flat roof tile for obtaining a green body, by pressing the extruded body, a connecting portion is provided between the roof tile main body portion and the under wrap portion of the green body, and the connecting portion is connected from the under wrap portion to the roof tile main body. It is characterized by being inclined at 30 to 60 degrees toward the part.
[0015]
Therefore, in the method for producing a flat roof tile according to claim 1, the extrusion molding is pressure-molded to provide a connecting portion between the tile body portion and the underlap portion of the molding base, and from the underlap portion to the roof tile. Since the connection part inclined at 30 to 60 degrees toward the main body part is provided, the raw material in the pressure molding can easily reach the inside of the mold, and the connection part is the boundary between the main body part and the underlap part of the molding base. The density of the raw material in the material is less different than other parts, and the distortion and cracks that tend to occur at the connecting part, which is the boundary between the body part and the underlap part of the molding substrate, are suppressed during drying and firing. .
[0016]
Moreover, the connection part which is a boundary of the main-body part and underlap part of a shaping | molding base is inclined by 30 to 60 degree | times by press-molding an extrusion molding.
Therefore, the orientation of the clay particles at the connecting portion, which is the boundary between the main body portion and the underlap portion of the molding substrate, is suppressed from differing from other parts in combination with the relaxation of the difference in the density of the raw material. Strain and cracks that tend to occur near the boundary between the tile main body and the underlap during firing are further suppressed.
[0017]
The method for producing a flat roof tile according to claim 2 is the method for producing a flat roof tile according to claim 1, wherein the extruded body is provided with a tile main body planned portion, an underlap planned portion and a connection planned portion, and a cross-sectional configuration of the extruded molded body. Is substantially corresponding to the cross-sectional shape in the width direction of the forming substrate from the planned underlap portion to the planned connection portion and the tile main body planned portion.
[0018]
Therefore, the method for producing a flat roof tile according to claim 2 has the same effect as that of the drying method according to claim 1, but prior to the pressure molding, the tile body pre-planar portion and the underlap pre-planar portion are formed on the extruded body. In addition, the cross-sectional configuration of the extruded body is substantially matched with the cross-sectional configuration in the width direction of the molding base from the planned underlap portion to the planned connection portion and the tile main body planned portion. The material density in the mold becomes easier to spread more smoothly in the mold, and the density of the material at the connection part, which is the boundary between the tile body part and the underlap part of the molding body, is further relaxed, and the dryness is reduced. In addition, distortion and cracks that tend to occur in the connecting portion that is the boundary between the tile main body portion and the underlap portion of the molding base during firing are drastically suppressed.
[0019]
In addition, during pressure molding, the orientation of the clay particles at the connecting part, which is the boundary between the tile main body part and the underlap part of the molding base, is further reduced from the difference with other parts, and the density of the raw material is reduced. Coupled with further alleviation of the difference, strain and cracks that tend to occur near the boundary between the tile main body portion and the underlap portion during drying and firing are further suppressed.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
A method for manufacturing a flat roof tile according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a forming substrate in a flat roof tile manufacturing method according to an embodiment of the present invention as seen from the front, FIG. 2 is a cross-sectional view of an extruded product before pressure forming as seen from the front, and FIG. FIG. 4 is an enlarged view of the main part showing the density state of the raw material of the molding base and the orientation of the clay particles, and FIG. 5 is the molding base of the flat roof tile according to this embodiment. FIG. 6 is a cross-sectional view of an extruded product according to another embodiment as viewed from the front, FIG. 7 is a perspective view of a flat roof tile according to the prior art, and FIG. 8 is a perspective view of the extruded product according to the prior art. FIG. 9 is a cross-sectional view of a main part showing the density state and orientation of a molding substrate during pressure molding in the prior art.
[0021]
(Extruded product)
The extrusion-molded body 10 is obtained by an extrusion-molding machine, but is cut into a predetermined dimension for pressure molding as a subsequent process.
The extrusion-molded body 10 is substantially plate-shaped and includes a tile main body planned portion 12, an underlap planned portion 14, a connection planned portion 16, and an overlap planned portion 18 (see FIG. 2).
And when the extrusion molding 10 is pressure-molded, it becomes the molding base 30 mentioned later.
[0022]
The tile main body planned portion 12 is a portion corresponding to the tile main body portion 32 in the molding base 30 and occupies most of the extruded molded body 10.
The tile main body planned portion 12 is in a horizontal state, and a connection planned portion 16 is provided that is inclined slightly downward from one side of the tile main body planned portion 12 (see FIG. 2).
[0023]
The planned connection portion 16 is a part corresponding to the connection portion 36 of the molding substrate 30, and the planned connection portion 16 in this embodiment is inclined downward by 35 degrees toward the underlap planned portion 14.
[0024]
The underlap planned portion 14 is provided in the horizontal direction from one side of the connection planned portion 16, and is a portion corresponding to the underlap portion 34 of the molding substrate 30.
On the other hand, a planned overlap portion 18 is provided on the other side of the tile main body planned portion 12 and corresponds to the overlap portion 38 of the molding substrate 30.
[0025]
Further, in this embodiment, the bulging portions 22 corresponding to the reinforcing ribs 42 provided on the back surface of the molding substrate 30 are provided at three positions with a predetermined interval from the tile main body planned portion 12.
[0026]
As described above, the extrusion molded body 10 according to this embodiment is referred to as an underlap planned portion 14, a connection planned portion 16, a roof tile planned portion 12, and an overlap planned portion 18 from one side to the other side in the cross section. Configured in order.
[0027]
And the site | part in a horizontal state is the overlap plan part 18, the tile main body plan part 12, and the underlap plan part 14, and the connection plan part 16 is inclined.
In the cross section of the extruded body 10, a line passing through substantially the center of the tile main body planned portion 12 and the overlap planned portion 18 is defined as a center line M, and a line passing substantially the center of the underlap planned portion 14 is defined as a center line N. Assuming that the line passing through the approximate center of the connection planned portion 16 is the center line Y, the center lines M and N are parallel to each other, and the acute angle formed by the center lines Y and N is 35 degrees.
[0028]
The reason for inclining the connection scheduled portion 16 of the extruded molded body 10 is that one side of the roof tile main body portion 32 in the molding base 30, the connecting portion 36, and the boundary between the connecting portion 36 and the underlap portion 34 during pressure forming described later. That is, in order to suppress the occurrence of a significant difference in the orientation of the clay particles associated with the pressure molding in the vicinity of the boundary between the roof tile main body 32 and the underlap portion 34.
[0029]
That is, the overlap scheduled portion 18, the majority of the tile main body planned portion 12, and the underlap planned portion 14 in the extruded molded body 10 are in a horizontal state, and are basically in a horizontal state even when molded on the molding base 30 by pressure molding. Therefore, the change in the orientation of the particles is small.
[0030]
On the other hand, the vicinity of the connection planned portion 16 of the extruded molded body 10, that is, the vicinity of the boundary between the tile main body planned portion 12 and the underlap planned portion 14, is molded into a substantially right-angled step shape in the molding base 30 by pressure molding. The change is large compared to the change in the shape of the tile main body planned portion 12, the underlap planned portion 14, and the overlap planned portion 18 in the horizontal state, and in the vicinity of the boundary between the tile main body planned portion 12 and the underlap planned portion 14. The orientation of the particles will change significantly.
[0031]
Therefore, a portion where the change in orientation of the clay particles is large and a portion where the change is small are generated in the molding substrate 30, and the orientation of the particles in the molding substrate 30 is remarkably different depending on the portion.
This remarkable difference in the orientation of the clay particles causes distortion and cracking of the molding substrate 30 during drying and firing, and the change in the orientation of the clay particles tends to occur in a concentrated manner.
[0032]
In this embodiment, a change in the orientation of particles in the vicinity of the boundary between the tile main body planned portion 12 and the underlap planned portion 14 is suppressed during pressure molding, and the orientation of the clay particles in the molding substrate 30 is a site. In order to suppress a significant difference between the tile main body 32 of the molded body 30 to be described later, the connection planned portion 16 and the underlap planned portion 14 are arranged from one side of the tile main body planned portion 12 of the extruded body 10. Is substantially corresponding to the cross-sectional shape from the connecting portion 36 to the boundary between the underlap portion 34 and the connecting portion 36.
[0033]
In particular, in this embodiment, the inclination angle of the connection planned portion 16 of the extrusion molded body 10 is about 35 degrees, and even if the extrusion molded body 10 is molded from the extrusion molded body 10 to the molding substrate 30 by pressure molding, the connection planned portion 16 is. From 35 degrees to 45 degrees of the connecting portion 36, and the difference is 10 degrees (see FIGS. 1 and 2).
[0034]
According to the inventor's test, it is confirmed that if the change in the inclination angle of the planned connection portion 16 by pressure molding is within 20 degrees, it is more effectively suppressed against strain and cracks during drying and firing. Thus, the remarkable difference in the orientation of the clay particles and the raw material density in the molding substrate 30 is suppressed.
[0035]
Therefore, in the case of this embodiment in which the inclination angle of the connection portion 36 in the molding substrate 30 is 45 degrees, the inclination angle of the connection scheduled portion 16 may be freely set in the range of 25 to 45 degrees.
[0036]
In addition, when setting the inclination angle of the connection part 36 in the shaping | molding base 30 in the range of 30-60 degrees, the inclination angle of the connection scheduled part 16 in the extrusion molding 10 is the difference of the angle of the connection part 36 and the connection scheduled part 16. Is within 20 degrees, the minimum is 10 degrees and the maximum is 50 degrees, which is in a range substantially corresponding to the cross-sectional shape in the width direction of the forming substrate 30.
[0037]
Obtained by extrusion molding by continuously providing the planned connection portion 16 and the underlap planned portion 14 from one side of the tile main body planned portion 12 and extruding so that the inclination angle of the planned connection portion 16 is about 35 degrees. Since the cross-sectional shape in the width direction of the extruded molded body 10 substantially corresponds to the cross-sectional shape in the width direction of the molding substrate 30, the resistance of the raw material to the forming die is reduced in the pressure forming, and the raw material is sufficiently contained in the forming die. It becomes easy to go around.
[0038]
Therefore, the density of the raw material in the vicinity of the boundary between the tile main body portion 32 and the underlap portion 34 in the molding substrate 30 is not greatly different from that in other portions, and the orientation of the clay particles described above is remarkable. Combined with the suppression of the difference, it is possible to suppress distortion and cracking during drying and firing due to the difference in the density of the raw materials.
[0039]
In this embodiment, in order to obtain a more preferable forming substrate 30 for suppressing distortion and cracks, the extruded connection part 16 is provided with the inclined connection planned part 16, but the inclined connection planned part 16 is provided. Needless to say, even if a plate-like extrusion molded body is simply used as in the prior art, the difference in density and orientation of the raw material of the molding base obtained by pressure molding is suppressed.
[0040]
(About forming substrate)
The molding substrate 30 according to this embodiment is composed of a tile main body portion 32, an underlap portion 34, a connection portion 36, an overlap portion 38, and a reinforcing rib 42, and is different from a flat roof tile as a product on the form. Absent.
[0041]
The molding substrate 30 in this embodiment is obtained by press-molding the extruded body 10, and specific means for press-molding are a press molding machine and an upper mold 44 attached to the press molding machine. And a lower die 46 (see FIGS. 2 and 3).
[0042]
In the molding substrate 30 in this embodiment, an overlap portion 38 is provided on the other side of the tile main body portion 32, and on the other hand, three reinforcing ribs 42 are provided on the back surface of the tile main body portion 32. The device which improves the intensity | strength of is designed.
And the underlap part 34 is provided through the connection part 36 so that it may become a level | step difference shape with respect to the tile main-body part 32. FIG.
A connecting portion 36 that is inclined at 45 degrees in the width direction is provided between the underlap portion 34 and the roof tile main body portion 32.
[0043]
In the cross section of the molding substrate 30, a line passing through substantially the center of the tile main body 32 and the overlap part 38 is a center line m, a line passing through the center of the underlap scheduled part 34 is a center line n, and a connection planned part When a line passing through the center of 36 is a center line x, the center lines m and n are parallel to each other, and the acute angle formed by the center lines x and n is 45 degrees.
[0044]
Since the connecting portion 36 is inclined differently from the conventional one, the orientation of the clay particles in the connecting portion 36 that has been subjected to pressure molding is different from that of other portions (the tile main body portion 32, the underlap portion 34, the overlap portion 38. ) And not significantly different.
[0045]
That is, the roof tile main body 32, the underlap portion 34, and the overlap portion 38 are molded from the extruded molded body 10 to the molding substrate 30, but basically maintain a horizontal state and have little change in form.
[0046]
However, in order to maintain the function as a flat roof tile, the underlap portion 34 and the roof tile body portion 32 must be provided in steps.
[0047]
Therefore, the pressure is formed so that the connecting portion 36 is inclined at 45 degrees, but the connecting portion 36 is inclined within a range in which the function of the flat roof tile is maintained, and the molding from the extruded molded body 10 to the forming substrate 30 is performed. It is intended to suppress a change in the form of the connecting portion 36.
Since the change in the shape of the connecting portion 36 is suppressed, the change in the orientation of the clay particles in the connecting portion 36 is reduced in the molding from the extruded molded body 10 to the molding substrate 30, and the clay particles are compared with other portions. The significant difference in the orientation is suppressed (see FIG. 4).
[0048]
Therefore, since there is no significant difference in the orientation of the clay particles due to the portion of the molding substrate 30, distortion and cracking during drying and firing are suppressed.
[0049]
Further, by pressure forming so that the connecting portion 36 is inclined at 45 degrees, the resistance of the raw material to the forming die is reduced, and the raw material is easily spread through the forming die, so that the tile main body portion 32 in the forming base 30 is obtained. The density of the raw material in the vicinity of the boundary between the underlap portion 34 and the underlap portion 34 is not significantly different from that of other portions, coupled with the suppression of the significant difference in the orientation of the clay particles described above. Further, it is possible to suppress strain and cracks during drying and firing due to the difference in the density of the raw materials (see FIG. 4).
[0050]
In this embodiment, as the most preferable example, the tile main body planned portion 12, the connection planned portion 16 and the underlap planned portion 14 of the extrusion molded body 10 are provided, and the inclination angle of the connection planned portion 16 is 35 degrees. Extrusion molding is performed, and the obtained extrusion-molded body 10 is pressure-molded so that the connecting portion 36 between the tile main body portion 32 and the underlap portion 34 of the molding base 30 is inclined 45 degrees in the width direction. It is.
[0051]
In this case, it was obtained by the synergistic effect of obtaining the extrusion molded body 10 in which the above-described connection planned portion 16 is provided and press-molding the extrusion molded body 10 so that the connection portion 36 is inclined. The molding substrate 30 is greatly suppressed from being strained or cracked during drying or firing.
[0052]
However, the advantage explained above can be obtained without impairing the function of the flat roof tile as long as the connecting portion 36 of the molding substrate 30 has an inclination angle in the range of 30 to 60 degrees.
[0053]
Next, an extruded product according to another embodiment will be described.
The extrusion molded body 50 of this embodiment substantially corresponds to the cross-sectional shape of the molding substrate 30 in the width direction, and similarly to the previously described embodiment, the tile main body planned portion 52 and the underlap planned portion 54. The connection planned portion 56, the overlap planned portion 58, and the bulging portion 62 are provided, and the portion from the roof tile planned portion 50 to the underlap planned portion 54 through the connection planned portion 56 has a mountain shape. (See FIG. 6).
[0054]
The mountain shape is composed of a main body inclined portion 64 of the roof tile main body portion 52 and a connection inclined portion 66 of the planned connection portion 56.
And the inclination angle of the main body inclination part 64 is 15 degree | times, and the inclination angle of the connection inclination part 66 is 25 degree | times (refer FIG. 6).
[0055]
In the cross section of the extruded product 50, a line passing through substantially the center of the tile main body planned portion 52, the overlap portion 58 and the underlap planned portion 54 excluding the main body inclined portion 64 is defined as a center line a, and the center of the connection planned portion 56 is defined. If the line passing through is the center line b and the line passing through the center of the main body inclined portion 64 in the tile main body planned portion 52 is the center line c, the acute angle formed by the center lines a and b is 25 degrees, and the other center line The acute angle formed by b and c is 15 degrees.
[0056]
By adopting the extrusion molded body 50 of this embodiment, there is an advantage that handling of the extrusion molded body 50 on the conveyance surface becomes easy, such as a conveyance device such as a conveyor is not complicated in conveying the extrusion molded body 50. .
[0057]
And by pressing and molding the extrusion molded body 50 according to this embodiment, the molding substrate 30 described in the previous embodiment is obtained, and distortion and cracks of the molding substrate 30 are similarly caused during drying and firing. Needless to say, it is suppressed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a forming substrate in a method for producing a flat roof tile according to an embodiment as seen from the front.
FIG. 2 is a cross-sectional view of an extruded product before pressure molding as seen from the front.
FIG. 3 is a cross-sectional view of the molding substrate after pressure molding as seen from the front.
FIG. 4 is an enlarged view of the main part showing the density state of the raw material of the molding substrate and the orientation of the clay particles.
FIG. 5 is a perspective view of a flat roof tile according to this embodiment.
FIG. 6 is a cross-sectional view of an extruded product according to another embodiment as seen from the front.
FIG. 7 is a perspective view of a flat roof tile according to a conventional technique.
FIG. 8 is a perspective view of an extruded product according to a conventional technique.
FIG. 9 is a cross-sectional view of a main part showing the density state and orientation of a molding base during pressure molding in the conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Extrusion molded body 12 Tile main body planned part 14 Underlap planned part 16 Connection planned part 18 Overlap planned part 22 Swelling part 30 Molding base 32 Tile body part 34 Underlap part 36 Connection part 38 Overlap part 42 Reinforcement rib 44 On Mold 46 Lower mold 50 Extrusion body 52 Tile main body planned portion 54 Underlap planned portion 56 Connection planned portion 58 Overlap planned portion 62 Swelling portion 64 Main body inclined portion 66 Connection inclined portion A Tile main body portion B Underlap portion C Overlap Part D Connection part E Extrusion G G Mold H Flat roof tile (molding base)
P Entrainment Q Insufficient filling

Claims

In a method for producing a flat roof tile, a plate-like extruded product is obtained by extruding a clay raw material, and a plate-like extruded product is formed by pressure molding.
By pressure forming the extruded body, a connecting portion is provided between the tile body portion and the underlap portion of the molding base, and the connecting portion is inclined at 30 to 60 degrees from the underlap portion toward the tile body portion. A method for producing a flat roof tile, characterized by comprising:

The extruded body is provided with a tile main body planned portion, an underlap planned portion and a connection planned portion,
2. The method for producing a flat roof tile according to claim 1, wherein the cross-sectional shape of the extruded product is made to substantially correspond to the cross-sectional shape in the width direction of the forming substrate from the underlap planned portion to the connection planned portion and the tile main body planned portion. .