RUN-FLAT TIRE

• Main Authors: TAMADA SATOSHI, OHASHI SHOICHI, SUGIMARU SATOSHI, UEDA MASAHIRO, YOKOYAMA TAKASHI
• Format: Patent
• Language: English; Japanese
• Published: 17.12.2015
• Subjects: CABLES OTHER THAN ELECTRIC; CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, ORYARNS; DEVICES OR ARRANGEMENTS RELATED TO TYRES; MECHANICAL FINISHING OF YARNS OR ROPES; PERFORMING OPERATIONS; REPAIRING, OR CONNECTING VALVES TO, INFLATABLE ELASTIC BODIESIN GENERAL; ROPES; ROPES OR CABLES IN GENERAL; TEXTILES; TRANSPORTING; TYRE CHANGING OR REPAIRING; TYRE INFLATION; VEHICLE TYRES; VEHICLES IN GENERAL; WARPING OR BEAMING; YARNS; YARNS OR THREADS

PROBLEM TO BE SOLVED: To improve abrasion resistance while suppressing deterioration of run-flat durability and riding comfortableness.SOLUTION: A run-flat tire includes side reinforcement rubber parts 7 which reinforce sidewall parts 2. Belts 9 are formed of a main filament bundle 22 made by arranging a plurality of main filaments 21 in a row without twisting them, and a flat steel cord 20 is applied to the belts 9. The steel cord 20 has an n+1 structure (where n is 3 to 6) formed by winding a wrapping filament 23 around the main filament bundle 22. In the steel cord, the ratio Da/Db of a cord short diameter Da after pressing to a cord short diameter Db before pressing is 0.80 or less, and the ratio R1/R2 of an in-plate rigidity R1 to an out-of-plate rigidity R2 is 10 to 30. A fiber cord forming a belt reinforcement layer 10 is a nylon fiber cord with a single twisting structure, and its twisting coefficient K is 750 to 1100. 【課題】ランフラット耐久性や乗り心地性の低下を抑えながら、耐摩耗性を向上する。【解決手段】サイドウォール部２を補強するサイド補強ゴム部７を備えたランフラットタイヤにおいて、ベルト９には、主フィラメント２１を複数本撚り合わせることなく一列に引き揃えて主フィラメント束２２とし、１本のラッピングフィラメント２３をその周囲に巻き付けてなるｎ＋１構造（ｎ＝３〜６）の扁平なスチールコード２０を適用する。該スチールコードは、押圧前のコード短径Ｄｂに対する押圧後のコード短径Ｄａの比Ｄａ／Ｄｂが０．８０以下であり、かつ面外剛性Ｒ２に対する面内剛性Ｒ１の比Ｒ１／Ｒ２が１０以上３０以下である。ベルト補強層１０を構成する繊維コードは、片撚り構造のナイロン繊維コードで撚り係数Ｋが７５０〜１１００である。【選択図】図１