Pneumatic vehicle tire with four steel cord belt plies

Abstract

A pneumatic vehicle tire of a radial type of construction is for heavy trucks and has a four-ply belt (3). Each belt ply (7, 8, 9, 10) contains steel cords as reinforcing elements which run parallel to one another in each belt ply. Not only are the angles (, ) that the steel cords in the second and third belt plies (8, 9) form with the circumferential direction (A-A) approximately equal, but also the angles (, ) that the steel cords in the first and fourth belt plies (7, 10) form with the circumferential direction (A-A) are likewise approximately equal.

Claims

1. A pneumatic vehicle tire having a radial configuration for heavy trucks and defining a circumferential direction A-A, the pneumatic vehicle tire comprising: a four ply belt having a radially innermost first belt ply, a second belt ply, a third belt ply, and a fourth belt ply; a rubber ply arranged between said third belt ply and said fourth belt ply; said first, second, third, and fourth belt ply each including steel cords configured as reinforcement members; said steel cords of each of said first belt ply, said second belt ply, said third belt ply, and said fourth belt ply running parallel to the other steel cords of the same belt ply; said steel cords of said first, second, third, and fourth belt plies having a predetermined slope sequence of rightward increasing (R) and leftward increasing (L) slope with respect to the circumferential direction A-A starting with said steel cords of said radially innermost first belt ply; said steel cords of said second belt ply enclosing an angle with the circumferential direction A-A; said steel cords of said third belt ply enclosing an angle with the circumferential direction A-A; said angle and said angle being equal; said steel cords of said first belt ply enclosing an angle with the circumferential direction A-A; said steel cords of said fourth belt ply enclosing an angle with the circumferential direction A-A; said angle and said angle being equal; wherein said rubber ply has a thickness in the range of 1.5 mm to 3.5 mm; wherein said angle and said angle are 40; and wherein said angle and said angle are 24.

2. The pneumatic vehicle tire of claim 1, wherein: said steel cords of said first belt ply and said second belt ply have a rightward increasing slope with respect to the circumferential direction A-A; and, said steel cords of said third belt ply and said fourth belt ply have a leftward increasing slope with respect to the circumferential direction A-A.

3. The pneumatic vehicle tire of claim 1, wherein: said steel cords of said first belt ply, said second belt ply and said fourth belt ply have a rightward increasing slope with respect to the circumferential direction A-A; and, said steel cords of said third belt ply have a leftward increasing slope with respect to the circumferential direction A-A.

4. The pneumatic vehicle tire of claim 1, wherein: said steel cords of said first belt ply and said third belt ply have a rightward increasing slope with respect to the circumferential direction A-A; and, said steel cords of said second belt ply and said fourth belt ply have a leftward increasing slope with respect to the circumferential direction A-A.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described with reference to the drawings wherein:

(2) FIG. 1 shows a partial cross section through one half of a pneumatic vehicle tire in the region of the belt and of the tread; and,

(3) FIG. 2 is a plan view of an alternative embodiment of the belt plies.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

(4) FIG. 1 shows a cross section through the tread and the belt region of a pneumatic vehicle tire for trucks in a conventional standard structure having a carcass 1 including steel cords as reinforcement members, an inner layer 2 impermeable to air, a multi-ply belt 3 and a profiled tread 6.

(5) The belt 3 has four belt plies 7, 8, 9 and 10, wherein the fourth, radially outermost belt ply 10 is the narrowest of all the plies and forms the protective ply. The first belt ply 7 is the barrier ply, the second belt ply 8 and the third belt ply 9 are the working plies. The widest belt ply is the second belt ply 8, which thus overlaps the first belt ply 7 completely. The third belt ply 9 is somewhat wider than or the same width as the first belt ply 7. The fourth belt ply 10 can furthermore be embodied so as to have the same width as the third belt ply 9. An additional rubber ply 11 may be arranged between the third belt ply 9 and the fourth belt ply 10.

(6) All the belt plies (7, 8, 9, 10) include reinforcement members which are embedded in a rubber compound, the belt rubber, and are made from steel cord, for example steel cord with a 30.2 mm+60.35 mm structure. Of course, it is also possible for steel cords with a different structure to be used in the belt plies.

(7) As FIG. 2 shows, the steel cords in each of the plies 7, 8, 9 and 10 run parallel to one another and form respective angles , , and with the circumferential direction of the tire indicated by the line A-A. The slope of the steel cords relative to the circumferential direction in the individual belt plies (7, 8, 9, 10) is such that, starting with the radially innermost belt ply 7, the sequence for the four plies is RRLR (rightward slope, rightward slope, leftward slope, rightward slope). In the case of a four-ply belt configured in accordance with the invention, the steel cords in the first, second and fourth belt plies 7, 8 and 10 thus slope to the right in relation to the circumferential direction A-A. The angle and the angle formed by the steel cords of the first belt ply 7 and the fourth belt ply 10 with the circumferential direction A-A is approximately the same and is between 40 and 55 or, in an alternative embodiment, between 40 and 46, for example 40. The angle and the angle formed by the steel cords in the second belt ply 8 and the third belt ply 9 with the circumferential direction A-A is likewise approximately the same and lies between 10 and 30.

(8) For tires configured in accordance with the invention, the angles , , and in the individual belt plies 7, 8, 9 and 10 can, for example, be as follows:

(9) =50, =18, =18, =50 or

(10) =50, =24, =24, =50 or

(11) =46, =18, =18, =46.

(12) Radial truck tires having steel cords angled in accordance with the invention in the belt plies have a significantly improved abrasion pattern in the shoulder regions, especially when they are used on the front axle of trailers or on the drive axle of wide base tires or low aspect ratio tires, and free-wheeling grooves occur significantly later, after a higher mileage, than with tires that have steel cords at conventional angles in the belt plies.

(13) Low aspect ratio tires refers to tires with an aspect ratio<50%.

(14) It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.

LIST OF REFERENCE NUMERALS (PART OF THE DESCRIPTION)

(15) 1 Carcass 2 Inner layer 3 Belt 6 Tread 7 Belt ply 8 Belt ply 9 Belt ply 10 Belt ply 11 Rubber Ply