Abstract:
A pneumatic tire having a carcass and a belt reinforcing structure is disclosed. The carcass comprising at least one inner ply which is wound around an annular bead member and extends radially outward towards the crown forming a turnup end; said tire further including a rubber apex located radially outward of said bead and having a radially outer end, wherein said turnup end is located radially outward of said rubber apex, and a reinforcement member having a first end and a second end, wherein the first end is positioned adjacent said apex, and the second end is radially outward of the apex outer end.

Description:
CROSS REFERENCE TO OTHER APPLICATIONS  
       [0001]    This application claims the benefit of and incorporates by reference U.S. Provisional Application No. 61/421,837, filed Dec. 10, 2010. 
     
    
     FIELD OF THE INVENTION  
       [0002]    The present invention is directed to a tire. More specifically, the present invention is directed to a tire suitable for use as a passenger tire. 
       BACKGROUND OF THE INVENTION  
       [0003]    A conventional radial-ply automobile tire includes radial plies that are wrapped around two annular inextensible beads. In the tire making process, a green tire carcass (“green” meaning as yet uncured and still tacky) is built by sliding a green innerliner and radial ply over a tire “building drum” (or “building mandrel”). Two beads (each comprising a cable of steel filaments encased in green rubber) are then slid over the carcass, one at each side. The portions of the plies that extend beyond the beads are then turned up around the beads, forming “turn-ups”. Then, the portion of the plies between the beads is expanded radially outward so as to contact the ply turn-ups. The annular cross-sectionally triangular rubber filler bounded by the turned up ply and the bead is called an “apex”. 
         [0004]    The choice of triangular dimensions and material properties of the apex affects the performance of the tire, such as tire weight, sidewall stiffness, handling, ride comfort, heat, material fatigue, and tire life. For example, since the apex extends up much of the length of the sidewall, increasing the stiffness of the apex increases the stiffness of the sidewall, yielding less sidewall flexing and hence less flexural heat and material fatigue, but at the cost of a rougher ride. Increasing the apex&#39;s radial length (so that it travels farther up the sidewall) further stiffens the sidewall and improves handling, which is beneficial for “high performance” tires. 
         [0005]    Tire designers have found that they would have wider choice of, and tighter control over, tire performance if they had wider flexibility in choice of apex design—that is, if they could specify longer apexes than conventionally used, and apexes with multiple layers of different material (“compound apexes”). The use of compound apexes unfortunately can add to increased tire weight, and thus negatively impact tire rolling resistance. Thus it is desired to have an improved tire design with an improved bead area that has lower weight and lower rolling resistance. At the same time, it is desired to have a tire with improved riding comfort but still having a good stiffness in the lower sidewall region for handling purposes. 
       DEFINITIONS  
       [0006]    The following definitions are applicable to the present disclosure and are used consistently as defined below: 
         [0007]    “Apex” means an elastomeric filler located radially outward of the bead core and between the plies and the turnup ply; 
         [0008]    “Axial” and “axially” are used herein to refer to lines or directions that are parallel to the axis of rotation of the tire; 
         [0009]    “Bead” or “Bead Region” means that part of the tire comprising an annular tensile member wrapped by ply cords and shaped, with or without other reinforcement elements such as flippers, chippers, apexes, toe guards and chafers, to fit the design rim; 
         [0010]    “Bead base” means the portion of the bead that forms its inside diameter; 
         [0011]    “Bead core” means an annular hoop reinforcement in the bead region of the tire, commonly formed of steel wire, cords or cables; 
         [0012]    “Bead toe” means the portion of the bead which joins the bead base and the inside surface of the tire; 
         [0013]    “Belt structure” means at least one annular layer or ply of parallel cords, woven or unwoven, underlying the tread, unanchored to the bead, and having both left and right cords angles in the range from 15° to 35° with respect to the equatorial plane of the tire; 
         [0014]    “Circumferential” means lines or directions extending along the perimeter of the surface of the annular tire parallel to the Equatorial Plane (EP) and perpendicular to the axial direction; 
         [0015]    “Equatorial plane (EP)” means the plane perpendicular to the tire&#39;s axis of rotation and passing through the center of its tread; 
         [0016]    “Normal Inflation Pressure” refers to the specific design inflation pressure and load assigned by the appropriate stands organization for the service condition for the tire; 
         [0017]    “Radial” and “radially” are used to mean directions radially toward or away from the axis of rotation of the tire; 
         [0018]    “Rim” means a support for a tire or a tire and tube assembly upon which the tire beads are seated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0019]    The invention will be described by way of example and with reference to the accompanying drawings in which: 
           [0020]      FIG. 1  is a cross sectional view of a tire of the present invention. 
           [0021]      FIG. 2  is a cross sectional view of a second embodiment of a tire of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    The following language is of the best presently contemplated mode or modes of carrying out the invention. This description is made for the purpose of illustrating the general principals of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0023]      FIG. 1  illustrates a cross-sectional view of one half of a radial tire  20  of the present invention. The tire is symmetrical about the mid-circumferential plane so that only one half of the tire is illustrated. Alternatively, the tire may also be an asymmetric tire. The tire  20  as depicted is a passenger tire, but the disclosed invention may be applicable for light truck tires, radial medium truck tires, heavy load tires, industrial tires, off-the-road tires, or other types of tires. One skilled in the art will appreciate that for each type of tire, the internal construction, the tread configuration, and materials of construction will be selected for the desired performance of the tire and may not be identical to what is illustrated. As shown, the tire  20  comprises a pair of bead portions  24  each containing a bead core  26  embedded therein. The bead core  26  is an annular member which may comprise any desired cross-sectional shape, and is not limited to the square shape depicted. 
         [0024]    The passenger tire  20  further comprises a sidewall portion  28  extending substantially outward from each of the bead portions  24  in the radial direction of the tire, and a tread portion  22  extending between the radially outer ends of the sidewall portions  28 . The tire  20  further comprises a belt package  32  arranged under the tread rubber  22 . The belt package  32  is symmetrical about the mid-circumferential plane. 
         [0025]    Furthermore, the tire  20  is reinforced with a carcass  30  toroidally extending from one of the bead portions  24  to the other bead portion  24 . The carcass may include an air impervious inner liner  29  typically composed of butyl rubber. The carcass is further comprised of at least one ply  31 , preferably oriented in the radial direction. Preferably for a passenger tire application the carcass has only a single radial ply. The carcass ply  31  may comprise any suitable cord, typically polyester, rayon, nylon cords such as nylon-6,6 cords extending substantially perpendicular to an equatorial plane EP of the tire (i.e., extending in the radial direction of the tire). 
         [0026]    The carcass ply extends under the tread portion of the tire and is anchored to each bead. Preferably, the ply  31  is wrapped around each bead ending in a turnup end  40 . The turn up end  40  extends radially outward from the bead core  26  preferably in the range of one to three times the bead diameter as measured radially outward from the center of the bead core. More preferably the turnup extends radially outward in the range of one to two times the bead diameter as measured radially outward from the center of the bead core. Preferably, the ply is wrapped from axially inside the bead to a position axially outside of the bead. The ply is wrapped about the bead and an apex  50 . The apex is located radially outward of the bead core  26  and may comprise a triangular shaped rubber component having an end, wherein the apex decreases in thickness from the first end  51  adjacent the bead towards the second end or tip  52 . The tip of the apex preferably extends past the turnup end  40 , although the tip of the apex may be located radially inward of the turnup  40 . Located adjacent the apex is a support member  60  (also called reinforcement member). The support member (or support reinforcement member)  60  is positioned adjacent the apex, preferably axially outward and adjacent the apex. The support member  60  has a first end  62  which does not extend to the bead core  26  and does not wrap around the bead core or otherwise be in contact with the bead core  26 . The first end  62  of the support member  60  is located between the radially outer surface  27  of the bead core  26  and the ply turnup end  40 . The first end is preferably 1-3 mm, preferably 1-2 mm, radially outward of the bead core. The support member has a second end  64  which extends radially outward of the turnup end  40  and preferably radially outward of the tip of the apex  52 . Preferably, the second end  64  of the support member  60  is radially outward of the apex tip  52  on the order of 3 to 15 mm, preferably 3 to 7 mm or more preferably 3 to 5 millimeters or more. 
         [0027]    As shown in  FIG. 1  the first end  62  of the support member  60  is located between the apex and the ply  31 . This is the preferred embodiment. However, the first end of the support member  60  may also be located axially outward of the ply  31  as shown in  FIG. 2 . 
         [0028]    If the tire  20  is a symmetric tire, the support member  60  is preferably applied in the same way in the bead area on both sides of the tires. Alternatively, the support member  60  may be used also only in the bead area on one side of the tire making the tire an asymmetric tire at least in that respect. If the support member  60  is used only on one side of the tire, it is preferably applied on the inboard side of the tire when the tire is mounted on a vehicle in accordance with its specification. 
         [0029]    The support member  60  may be comprised of an aramid material or nylon material, with or without reinforcement textiles. The support member  60  is preferably a thin sheet of material preferably having a thickness on the order of 0.6 to 1.5 millimeter or 0.8 to 1.2 mm within a certain angle. The support member functions to increase longitudinal and radial stiffness in the bead/apex area. Depending on the support member materials and their properties (width, angle . . . ), the tire handling and comfort can be tuned. The support member may also be comprised of nylon, aramid, steel, polyester, carbon fiber, polyketone fiber, rayon, PN, PBO or a combination of two or more material thereof, with or without reinforcement textiles. 
         [0030]    Variations in the present inventions 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.