Metal cords and pneumatic tires using the same
AssigneeBridgestone Corporation
InventorsKuninori Nishizawa, Teruo Miura, Yoichi Watanabe, Hirohiko Takagi
Life of this patent
Estimating the term…
Abstract
A metal cord is constructed by twisting three metal filaments in the same direction, and satisfies Lmax.gtoreq.1.05d, Lmin.gtoreq.1d and Lmax/Lmin.gtoreq.1.05 (Lmax : center distance between longest separated metal filaments, Lmin : center distance between shortest separated metal filaments, d : diameter of metal filament), and has specified twisting pitch and elongation under a load of 5 kg/cord. A pneumatic tire comprises a belt composed of plural belt layers each containing the above metal cords arranged at a given inclination angle with respect to the circumferential direction of the tire.
Claims17
A metal cord constructed by twisting three metal filaments having the same filament diameter (d) in the same direction, said cord satisfying 3.0d.gtoreq.Lmax.gtoreq.1.05d, Lmin.gtoreq.1.0d and 3.0.gtoreq.Lmax/Lmin.gtoreq.1.05, wherein Lmax is a center distance between the longest separated metal filaments and Lmin is a center distance between the shortest separated metal filaments, and said cord containing a region having Lmax.gtoreq.1.5d in an amount of not less than 30% per cord length of 50 mm in the longitudinal direction, and said cord having a twisting pitch of 6.5-20 mm and an elongation of 0.2-1.2% under a load of 5.0 kg per cord.
A pneumatic tire comprising a carcass ply of substantially radial structure and a belt superimposed about a crown portion of the carcass ply and composed of plural metal cord layers each containing metal cords therein;
- said metal cord constructed by twisting three metal filaments having the same filament diameter (d) in the same direction, said cord satisfying 3.0d.gtoreq.Lmax.gtoreq.1.05d, Lmin.gtoreq.1.0d and 3.0.gtoreq.Lmax/Lmin.gtoreq.1.05, wherein Lmax is a center distance between the longest separated metal filaments and Lmin is a center distance between the shortest separate metal filaments, and said metal cord containing a region having Lmax.gtoreq.1.5d in an amount of not less than 30% per cord length of 50 mm in the longitudinal direction, and said metal cord having a twisting pitch of 6.5-20 mm and an elongation of 0.2-1.2% under a load of 5.0 kg per cord;
- said metal cords being arranged at an inclination angle of 17.degree.-25.degree. with respect to the circumferential direction of the tire in such a manner that a shortest vertical distance (L) between the most adjacent metal filaments in the opposed metal cords between the adjoining metal cord layers is within a range of 0.5-1.3 mm;
- and said tire having a ratio of belt width (B) to ground contact width of tread (H) of not more than 1.2.
Dependencies are inferred from the claim text.