BACKGROUND OF THE INVENTION 1, Field of the Invention This invention relates broadly to tires for vehicle. More particularly, this invention relates to cables for belts in radial tires.

2. State of the Art A pneumatic radial tire includes an annular tread having a belt incorporated therein, a pair of sidewalls which extend radially inward from both ends of the annular tread. and a bead portion provided at the inner end of each sidewall, During high-speed running, a strong centrifugal force is exerted on the annular tread of a tire, and under this centrifugal force, the annular tread deforms radially outwards The amount of tire deformation due to lifting is not uniform in the axial direction (i. e., the width direction of tire) of the annular tread and, on account of the difference in the rigidity of the belt, the deformation of the shoulder at either end of the tread is greater than the deformation of the center portion.

The deformation due to lifting also increases the temperature of the shoulder and can potentially destroy the adhesion between rubber and ; the steal cords in the belt at the shoulder. In addition, the resulting change in the shape of the tire portion that contacts the road surface often causes poor maneuverability at high speed and insufficient grip property.

The conventional means of solving this problem is to improve the belt rigidity by either increasing the diameter or number of belt cords or providing a reinforcement layer which extends radially outward of the belt. However, these methods increase the tire weight and are unable to meet the requirement for lighter tires, and the demand for a lighter tire is increasing today as the performance of vehicles is constantly improving. Further, an improvement in the belt rigidity leads to a higher tread rigidity and the resulting increase in the longitudinal rigidity of the tire taken as a whole will unavoidably lead to poor ride characteristics. The increased tread rigidity often causes other problems including higher road noise, lower endurance and poor performance on wet surfaces.

SUMMARY OF THE INVENTION A pneumatic radial tire according to the invention includes an annular tread having a belt incorporated therein, a pair of

sidewalls which extend radially inward from both ends of the annular tread and a bead portion provided at the inner end of each sidewall. The belt comprises a belt ply having a plurality of belt cords in preferably parallel arrangement. The belt cords being formed by twisting together a plurality of cables.

According to the invention, the cables are formed by twisting and then drawing through at least one die a plurality of metal strands so as to form a cable. According to a preferred aspect of the invention, at least one of the strands comprises carbon steel, and particularly super tensile steel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pneumatic radial tire according to the invention includes an annular tread having a belt incorporated therein, a pair of sidewalls which extend radially inward from both ends of the annular tread and a bead portion provided at : the inner end of occh sidewall. The belt comprises a belt ply having a plurality of belt cords in preferably parallel arrangement. The belt cords are formed by twisting together a plurality of cables and optionally some strands. The construction of numerous belted tires substantially similar to the above is known in the art. For example, p. s. Patent No. 5,242,001 to Kahrs et al., 6, 109, 017 to Kawatani, 6,058,997 to Nishida et al., 6,016,857 to Roesgen et al., 5, 894, 875 to Masaki et al. each generally discloses a belted

tire in accord with above construction, and are all hereby incorporated by reference herein in their entireties.

Now, according to the invention, the cables are formed by twisting and then drawing through at least one die a plurality of metal strands so as to form a cable. The construction of twisted and drawn cables are generally disclosed in my issued U. S. patents relating to twisted and drawn cables, namely U. S. Patent Nos, 5,994,647, and 6,049,042, and in my pending U. S. applications, namely 09/450, 679, 09/476, 195,09/149,957, 09/043,341, 09/044, 203, 09/531, 388, 09/060, 969, and 09/494,982, all of the patents and applications being hereby incorporated by reference herein in their entireties. According to a preferred embodiment of the invention, at least one of the strands comprises steel, more preferably carbon steel, and even more preferably super (high) tensile steel.

According to another preferred aspect of the invention, the strands, prior to twisting and drawing, may be coated to increase their bonding strength with the rubber of the tire. Preferred Coatings include brass (preferably 30-40% copper), pure zinc, and zinc cobalt, though other coatings may be used. Alternatively, the cables produced from the twisted and drawn strands may be coated

The twisted and drawn cables have increased tensile strength over metal and metal alloy strands and conventional cables of the same diameter. This permits smaller cables to be used to reduce the weight of the tire, as well as provides additional strength to the belts of the tire. In addition, the twisted and drawn cables are more flexible than conventional wires and cables of the same diameter further facilitating a tire with enhanced performance and wear characteristics. The tires according to the invention may be used for vehicles of every kind using tires including for example automotive, aircraft, emergency and rescue, earth moving and construction, and recreational vehicles In a modified form the invention has application for hoses specifically high pressure hoses in pneumatic and hydraulic uses.

In accordance with the invention, the cable formed by twisting and drawing undergoes compaction in a range of 1% to 50% from diameter of twisted cable to diameter of drawn cable. In accordance with the invention, cable compaction maybe accomplished by swaging or rolling the twisted cable.