Pneumatic tire with band cord modulus higher in side portion than in center portion of band
AssigneeSumitomo Rubber Industries, Ltd.
InventorNobuyoshi Yoshinaka
Life of this patent
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Abstract
A band (14) of a tire covers a belt (12). The band (14) is formed by a band ply (36). The band ply (36) includes a side portion (38) and a center portion (40). A band cord having a high modulus (Ms) is used for the side portion (38). Typically, a band cord to be a composite of a nylon fiber and an aramid fiber is used for the side portion (38). A band cord having a low modulus (Mc) is used for the center portion (40). Typically, a nylon fiber is used for the band cord of the center portion (40). A ratio (Ms/Mc) is 2.0 to 4.0. A ratio of a width (Ws) of the side portion (38) to a width (Wb) of the band (14) is 5.0% to 20.0%.
Claims11
A pneumatic tire comprising a tread having an external surface forming a tread surface, a pair of sidewalls extended almost inward in a radial direction from both ends of the tread, a pair of beads extended almost inward in the radial direction from the sidewalls, a carcass laid between both of the beads along insides of the tread and the sidewalls, a belt provided on the carcass at an inside in the radial direction of the tread, and a band positioned between the belt and the tread and covering the belt,
- wherein a band ply constituting the band is formed by a band cord and a topping rubber,
- the band ply is spirally wound in a circumferential direction,
- the band ply includes a side portion positioned in the vicinity of an edge of the belt and a center portion positioned in the vicinity of a center in an axial direction,
- a modulus of the band cord of the side portion is lower than 8000 N/mm2 and is higher than that of the band cord of the center portion, and
- a width Ws of the side portion is 5.0% to 20.0% of a width Wb of the band.
Dependencies are inferred from the claim text.