Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Reexamination Certificate
2001-11-01
2003-05-06
Johnstone, Adrienne C. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
C152S533000
Reexamination Certificate
active
06557605
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire, more particularly to a tread reinforcing structure being capable of improving tire noise and rolling resistance.
In order to improve high-speed durability of a pneumatic tire especially a radial tire for passenger cars, as shown in
FIG. 7A
, a single-layered full-width band (b
1
) over a breaker (a) is widely used. Here, a band means a cord layer whose cord angle is less than about 10 degrees usually less than 5 degrees with respect to the tire equator, and a breaker means a cord layer whose cord angle is more than 10 degrees usually more than 15 degrees.
Such a single-layered full-width band (b
1
) can reduce a road noise around a frequency of 250 Hz heard on the inside of a vehicle during running. By using a higher tensile modulus cord in the band (b
1
), such a road noise may be reduced more, but a pass-by noise heard on the outside of a vehicle during running tends to increase. It is effectual in reducing the pass-by noise to use axially spaced edge bands (b
2
) on the edge portions of a breaker (a) as shown in FIG.
7
B. Such axially spaced edge bands (b
2
) however, tend to increase the rolling resistance of the tire.
BRIEF SUMMARY OF THE INVENTION
It is therefore, an object of the present invention to provide a pneumatic tire, in which the rolling resistance and tire noise such as road noise and pass-by noise are improved.
According to the present invention, a pneumatic tire comprises
a carcass extending between bead portions through a tread portion and sidewall portions,
a breaker disposed radially outside a crown portion of the carcass,
a pair of axially spaced high modulus edge bands disposed radially outward of edge portions of the breaker and each made of one or more high modulus cords having a sectional area SH and a 2% modulus MH and wound substantially parallel to the tire circumferential direction at a cord count DH,
a low modulus middle band disposed radial outward of the breaker between the high modulus edge bands and made of one or more low modulus cords having a sectional area SL and a 2% modulus ML less than the 2% modulus MH and wound substantially parallel to the tire circumferential direction at a cord count DL, and
an elongation resistance index PH of each of the high modulus edge bands, which is defined as the product of the 2% modulus MH in N/sq.mm, the sectional area SH in sq.mm and the cord count DH per 1 cm width divided by 100, being in a range of 160 to 700.
Further, an elongation resistance index PL of the low modulus middle band, which is defined as the product of the 2% modulus ML in N/sq.mm, the sectional area SL in sq.mm and the cord count DL per 1 cm width divided by 100, may be set in a range of not less than 30 but less than 160.
REFERENCES:
patent: 5213642 (1993-05-01), Sponagel
patent: 5795417 (1998-08-01), Damke et al.
patent: 5922154 (1999-07-01), Lowenhaupt et al.
patent: 6058996 (2000-05-01), Suzuki
Hizume Makoto
Tanaka Takashi
Wada Yasuo
Yamazaki Kazumi
Yukawa Naoki
Birch Stewart Kolasch & Birch, LLP.
Johnstone Adrienne C.
Sumitomo Rubber Industries Ltd.
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