Patent Publication Number: US-2021178823-A1

Title: Truck tire

Description:
FIELD OF THE INVENTION 
     The invention relates in general to pneumatic tires, and more particularly for vehicles such as trucks. 
     BACKGROUND OF THE INVENTION 
     The commercial truck market is moving towards an increase in overall vehicle weight, which is due in part to the increase in weight of the motor and equipment. The increase in overall vehicle weight requires a tire capable of handling the additional loading. Thus, a tire with improved crown durability and increased load carrying capacity is desired. 
     SUMMARY OF THE INVENTION 
     The invention provides in a first aspect a pneumatic tire for use on trucks, the tire having a tread, sidewalls, and a pair of beads, and a belt reinforcement structure located radially inward of the tread, the belt structure consisting essentially of only three belts, wherein two of the belts are a pair of working belts, wherein the angle of the working belts range from about 12 degrees to about 35 degrees from the circumferential direction, wherein the working belts are extensible, wherein the third belt is a low angle belt having reinforcements angled at less than 5 degrees located between the working belts. 
     The invention provides in a second aspect a pneumatic tire for use on trucks, the tire having a tread, sidewalls, and a pair of beads, and a belt reinforcement structure located radially inward of the tread, the belt structure has only three belts, wherein two of the belts are a pair of working belts, wherein the angle of the working belts range from about 12 degrees to about 35 degrees from the circumferential direction, wherein the working belts are extensible, wherein the third belt is a low angle belt having reinforcements angled at less than 5 degrees located between the working belts. 
     Definitions 
     “Aspect Ratio” means the ratio of a tire&#39;s section height to its section width. 
     “Axial” and “axially” mean the lines or directions that are parallel to the axis of rotation of the tire. 
     “Bead” or “Bead Core” mean generally that part of the tire comprising an annular tensile member, the radially inner beads are associated with holding the tire to the rim being wrapped by ply cords and shaped, with or without other reinforcement elements such as flippers, chippers, apexes or fillers, toe guards and chafers. 
     “Belt Structure” or “Reinforcing Belts” means at least two annular layers or plies of parallel cords, woven or unwoven, underlying the tread, unanchored to the bead, and having both left and right cord angles in the range from 17° to 27° with respect to the equatorial plane of the tire. 
     “Bias Ply Tire” means that the reinforcing cords in the carcass ply extend diagonally across the tire from bead-to-bead at about 25-65° angle with respect to the equatorial plane of the tire, the ply cords running at opposite angles in alternate layers 
     “Block element” means a tread element defined by a circumferential groove or shoulder and a pair of laterally extending grooves. 
     “Breakers” or “Tire Breakers” means the same as belt or belt structure or reinforcement belts. 
     “Carcass” means a laminate of tire ply material and other tire components cut to length suitable for splicing, or already spliced, into a cylindrical or toroidal shape. Additional components may be added to the carcass prior to its being vulcanized to create the molded tire. 
     “Circumferential” means lines or directions perpendicular to the axial direction within + or −5 degrees. 
     “Cord” means one of the reinforcement strands, including fibers, which are used to reinforce the plies. 
     “Extensible” means a cable having a relative elongation at break of greater than 0.2% at 10% of the breaking load, when measured from a cord extracted from a cured tire. 
     “Inner Liner” means the layer or layers of elastomer or other material that form the inside surface of a tubeless tire and that contain the inflating fluid within the tire. 
     “Inserts” means the reinforcement typically used to reinforce the side edges of runflat-type tires; it also refers to the elastomeric insert that underlies the tread. 
     “Ply” means a cord-reinforced layer of elastomer-coated, radially deployed or otherwise parallel cords. 
     “Radial” and “radially” mean directions radially toward or away from the axis of rotation of the tire. 
     “Radial Ply Structure” means the one or more carcass plies or which at least one ply has reinforcing cords oriented at an angle of between 65° and 90° with respect to the equatorial plane of the tire. 
     “Rib” means a circumferentially extending strip of rubber of the tread which is defined by at least one circumferential groove and either a second circumferential groove or a lateral edge, wherein the strip is not divided by full depth grooves. 
     “Radial Ply Tire” means a belted or circumferentially-restricted pneumatic tire in which the ply cords which extend from bead to bead are laid at cord angles between 65° and 90° with respect to the equatorial plane of the tire. 
     “Side edge” means a portion of a tire between the tread and the bead. 
     “Sipe” means small slots or elongated void areas typically formed by thin steel blades, and which tend to remain closed, and function to increase traction. 
     “Laminate structure” means an unvulcanized structure made of one or more layers of tire or elastomer components such as the innerliner, side edges, and optional ply layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described by way of example and with reference to the accompanying drawings in which: 
         FIG. 1  is a cross-sectional view of a first embodiment of a tire of the present invention; and 
         FIG. 2  is a close-up view of the belt package of the tire of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a first embodiment of a pneumatic tire, suitable for use as a truck tire. The tire  10  has a tread  12  with a non-skid depth D. The tire tread  12  may comprise a plurality of circumferentially continuous ribs, which may vary, but are shown for example as ribs  31 ,  32  and  33 . Positioned between each rib is a circumferential groove  34 ,  35 ,  36 , which are preferably continuous. The tread may also comprise optional sipes (not shown). The tread pattern is not limited to same, and may comprise, for example, a plurality of blocks and grooves (not shown). 
     The tire  10  further comprises a casing  14  which includes two opposed sidewalls  16  which extend down from the tread  12  to the bead area. The casing of the tire may optionally include an inner liner  24  which is typically formed of halobutyl rubber which forms an air impervious barrier. The tire casing  14  further includes one or more radial plies  18  extending from the tread, down the sidewall to the tire bead  20 . Preferably the radial ply  18  is wrapped about or otherwise secured to each annular bead  20 . In the embodiment illustrated and not limited to same, there is only one ply  18  and it is wrapped around the bead in an inside out manner such that the ply ending  19  is located axially outward and radially outwards of the bead. The beads  20  may be any desired shape, but in this embodiment, it is shown as a hexagonal configuration with steel filaments. 
     The tire may further optionally include an apex  21  which may be shaped like a triangle. The ply turnup in the bead area may be optionally reinforced with a chipper  23  wrapped about the bead ply  18 . 
     The tire  10  further includes a belt package  50  which is located between the tread and the one or more plies  18 . The belt package may be comprised of only three belt layers of reinforcement. The ply  18  and the belt reinforcing structure  50  are made from cord reinforced elastomeric material, wherein the cords are typically steel wire or polyamide filaments and the elastomer preferably being rubber. 
     The belt reinforcing package  50  is limited to only three belts, and includes a pair of extensible working belts,  54 ,  56 . Belt  54  is located radially inwards of belt  56 . Belt  54  has a width which is about equal to the tread arc width. Preferably, belt  54  has a belt width substantially equal to the tread arc width. The breaker angle of belt  54  is between about 12 and 35 degrees, preferably with a right orientation, more preferably in the range of about 19 to about 25 degrees. Belt  54  is preferably made of high elongation wire, which is defined as being dipped in RFL and has a % elongation at 10% of the breaking load of greater than 0.4%, as measured from a cord taken from a cured tire. Alternatively, the cable has a % elongation at 10% of breaking load of greater than 1.7% when measurement is performed on a bare wire sample that has not been vulcanized in a tire. For example, the belt may be formed of wire having a wire construction of 3×7×, 3×4×, 4×4×. Preferably the wire has a construction of 3×7×0.22 HE. The EPI may range from about 8 to about 14. 
     Belt  56  is the second member of the working belt pair. Belt  56  has a width less than the width of belt  54  (the other working belt), and is preferably radially outward of belt  54 . Preferably, the belt  56  has a width less than the width of belt  54  by a step off, which may range from about 10 to about 20 mm. Belt  56  has a breaker angle between about 12 and 35 degrees, preferably with a left orientation, more preferably in the range of about 19 to about 25 degrees. Belt  56  is preferably made of high elongation wire, having the same construction with the same but opposite angular orientation as belt  54 . 
     The belt structure  50  further comprises a third belt  58  which is preferably located between the working pair belts,  54 ,  56 . The third belt  58  may also be located between belts  52  and  54  or radially outward of belt  56 . The third belt  58  has reinforcements that are oriented circumferentially at 5 degrees or less, preferably 0 degrees. The belt is preferably formed from spirally winding a rubberized strip of two or more cords. Preferably the strip has about 7 steel cords. Alternatively, the belt may be formed of a cut belt with the reinforcements oriented in the range of 0 to about 10 degrees from the circumferential direction. The third belt  58  has a width sized to avoid compression in the shoulder area. The belt width of the third belt  58  is preferably in the range of about 70% to about 80% of the tread arc width, and even more preferably in the range of 73-77%. The third belt  58  is wide enough to decrease the strain cycles in the breaker wedge, and is just stopped before the shoulder area to avoid 0 degree wire compression and a too round footprint. The belt structure of belt  48  may be steel formed of 4+3×0.35 construction or aramid. 
     The belt structure excludes an overlay belt or a transition belt, or any additional belts, and is limited to only the three belts described above. 
     The aspect ratio of the tire described above may vary. The aspect ratio is preferably in the range of about 50 to about 90. The tire may have a net to gross ratio in the range of about 70 to about 90, more preferably in the ratio of about 74 to about 86, more preferably about 78 to 84. 
     Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.