Patent Publication Number: US-2019184767-A1

Title: Post-cure sidewall stabilizing reinforcement and method of manufacturing

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a run-flat tire, and, more particularly, relates to a post-cure sidewall stabilizing run-flat insert and methods of manufacturing the same. 
     BACKGROUND OF THE INVENTION 
     It is well-known that automobile tires are provided in run-flat configurations. Run-flat tires are used by automobile manufacturers to eliminate the need for spare tires, thereby increasing available space within a vehicle and reducing vehicle curb weight. Many vehicle operators prefer the convenience of a run-flat tire because it is able to continue operating even under loss of inflation pressure. Run-flat tires are designed to be able to function for a limited time and distance at zero inflation pressure, also referred to in the art as a “zero (0) psi state.” 
     Conventional run-flat tires of the “self-supporting” type are known. These self-supporting type run-flat tires typically include a sidewall-stabilizing reinforcement (SSR) insert within the sidewall. The SSR insert  100  is conventionally made of a high durometer rubber sufficient to maintain the tire&#39;s rigidity/stiffness in the zero psi state and that is also capable of bearing a significant load during the zero psi state of the tire. Such SSR inserts  100   a - b  are disposed within each sidewall region or sidewall flex area between a body ply  102  and an inner liner  104 , as shown in  FIG. 1 . The SSR inserts  100   a - b  may extend from just below an edge of a belt structure  106  and terminate at an area above the bead core  108  (typically extending to approximately 0.50 inches above the bead core  108 ), as illustrated in  FIG. 1 . This position and orientation has been shown to carry vehicle loading in the zero psi state. During manufacturing of the conventional run-flat tire, the sidewall-reinforcing inserts  100   a - b  are applied at the tire assembly machine (TAM) after the inner liner  104  is applied to a run-flat building drum and before the body ply  102  is applied to the building drum. The sidewall-reinforcing inserts  100   a - b  are subsequently cured as part of a green tire in the conventional manner of curing tires. 
     U.S. Pat. No. 4,917,164 (hereinafter “the &#39;164 Patent”), incorporated herein by reference, discloses the use of such conventional crescent-shaped reinforcing inserts in the sidewalls of the tire to allow the tire to run for short durations with little or no air pressure. The sidewall-reinforcing inserts in the &#39;164 Patent have a Shore A hardness of between 65 and 85, and are positioned between the innerliner and carcass plies of the tire. The wall thickness of the reinforcing inserts is between 1 and 12 millimeters in the &#39;164 Patent. 
     While these self-supporting type run-flat tires offer satisfactory service under run-flat conditions, they have the disadvantage, under normal inflation conditions (i.e., when the tire is inflated to their service pressure or very close to their service pressure), of having inferior ride quality as compared to conventional tires (i.e., non-run flat pneumatic tires). The reduced ride quality of these self-supporting type run-flat tires is in large part a result of the additional rigidity provided by the cure-in SSR inserts  100 . Accordingly, providing a run-flat tire that provides run-flat support in a zero psi state, while also not sacrificing the ride quality of conventional tires is difficult to achieve. 
     To further complicate matters, solutions that increase the complexity of the tire manufacturing process are not practical due to the increased costs. In other words, there is an ongoing effort in the tire industry to improve the durability of run-flat tires, while also decreasing the costs and complexity involved in manufacturing run-flat tires. As is well-known in the art, complexity of the tire design and the tire assembly process results in increased production time and increased costs. 
     Prior art attempts to provide run-flat support within a tire cavity have been made, but are deficient. One such example is a device used in a run-flat tire and disclosed in U.S. Pat. No. 4,334,565 by Stokes. The tire disclosed in the Stokes patent includes a toroidal insert disposed in the tire cavity to support a load during a deflated condition. However, in such deflated condition, the ride behavior of the tire is similar to that of a deflated tire without the toroidal insert, which may be unacceptable. Also, the irregular shape of the toroidal insert and the central placement of the load-bearing members 38 and 40 primarily provides run-flat support in the central foot-print area, with the end portions 30 and 32 merely providing minor, ancillary support for the sidewalls. Further, because the toroidal insert extends across the rim portion, it may block heat from escaping the enclosed tire cavity via heat radiating through the metallic rim, thereby accelerating tire wear. 
     U.S. Pat. No. 4,953,291 by Markow discloses a device with two elastomeric members 12 and 14 connected to two corresponding flexible discs 16 and 18 that secure the device to the rim sections 8 and 10. During a deflation condition, the elastomeric members 12 and 14 of the Markow patent are translated radially outward, by the flexible discs 16 and 18, into the sidewall folds to support the collapsed sidewalls. The device of the Markow patent increases the complexity of the tire by requiring attachment of the device to a bracket 2 that is welded to the rim sections 8 and 10. Accordingly, the device of the Markow patent increases complexity of the overall tire design and the manufacturing processes, which is undesirable. 
     Therefore, a need exists to overcome the problems with the prior art as discussed above. 
     SUMMARY OF THE INVENTION 
     The invention provides a post-cure sidewall stabilizing reinforcement and method of manufacturing that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type. 
     With the foregoing and other objects in view, there is provided, in accordance with the invention, a run-flat tire including a pair of post-cure sidewall-stabilizing run-flat inserts, each of the pair of post-cure sidewall-stabilizing run-flat inserts extends circumferentially about a rotational axis of a tire; includes a first terminating end, and a second terminating end, opposite the first terminating end; and is disposed on a radially inner surface of a sidewall of a tire such that the first terminating end terminates above a bead core and the second terminating end terminates along at least one of the sidewall and a respective adjacent shoulder during a normal inflation condition of the tire. 
     In accordance with another feature of the present invention, each of the pair of post-cure sidewall-stabilizing run-flat inserts the first terminating end terminates 0.5 inches above the bead core. 
     In accordance with yet another feature of the present invention, the radially inner surface of the sidewall is a radially inner surface of an inner liner of the tire. 
     In accordance with another feature of the present invention, each of the pair of post-cure sidewall-stabilizing run-flat inserts is of an elastomeric material having a shore A hardness of at least 50. 
     In accordance with another feature of the present invention, each of the pair of post-cure sidewall-stabilizing run-flat inserts extends continuously 360 degrees about the rotational axis of the tire. 
     In accordance with an additional feature, an embodiment of the present invention further includes a tread; an inner liner disposed beneath the tread; a first bead portion and a second bead portion axially spaced apart from one another, each bead portion having a bead core and a bead filler; and at least one body ply having a main body ply portion extending about the tire, at least a portion of the main body ply portion disposed between the tread and the inner liner; and having a first turned-up portion and a second turned-up portion, the first turned-up portion looping around the first bead portion and the second turned-up portion looping around the second bead portion. 
     In accordance with another feature of the present invention, each of the pair of post-cure sidewall-stabilizing run-flat inserts includes at least a center rib disposed between a first side rib and a second side rib, the first and second side ribs separated radially from the center rib by a first decoupling groove and a second decoupling groove, respectively. 
     In accordance with yet another feature of the present invention, each of the pair of post-cure sidewall-stabilizing run-flat inserts further includes a third side rib and a fourth side rib separated radially from the first and second side ribs by a third decoupling groove and a fourth decoupling groove, respectively, and the third and fourth side ribs disposed outwardly from the center rib and the first and second side ribs. 
     In accordance with another feature of the present invention, each of the first and second decoupling grooves is defined by two rib walls that during the normal inflation condition of the tire, form a continuous circumferential groove; and during an uninflated condition of the tire, collapse on each other so as to close the continuous circumferential groove. 
     In accordance with a further feature of the present invention, each of the first and second decoupling grooves defines a groove cross-section that is formed as a generally V-shaped groove cross-section. 
     In accordance with a further feature of the present invention, each of the first and second decoupling grooves is defined by two rib walls that are adapted to move toward one another during deflection of the tire in the normal inflation condition of the tire. 
     In accordance with a further feature of the present invention, each of the first and second decoupling grooves is formed as a continuous circumferential groove extending about the rotational axis of the tire during the normal inflation condition of the tire; and each of the center rib and the first and second side ribs extends continuously in a circumferential direction 360 degrees about the rotational axis of the tire. 
     In accordance with another feature, an embodiment of the present invention includes a run-flat tire with a pair of post-cure sidewall-stabilizing run-flat inserts, each of the pair of post-cure sidewall-stabilizing run-flat inserts extends circumferentially about a rotational axis of a tire; is disposed on a radially inner surface of a sidewall of a tire; and includes at least a center rib disposed between a first side rib and a second side rib, the first and second side ribs separated radially from the center rib by a first decoupling groove and a second decoupling groove, respectively. 
     In accordance with a further feature of the present invention, each of the first and second decoupling grooves opens into a tire cavity during the normal inflation condition of the tire and is closed-off from the tire cavity during an uninflated condition of the tire. 
     In accordance with the present invention, a method for manufacturing a run-flat tire, the method includes steps of providing a green tire in a tire mold; curing the green tire in the tire mold; removing the cured tire from the tire mold; providing a pair of sidewall-stabilizing run-flat inserts including at least two circumferential ribs defining at least one circumferential groove; and after the step of removing the cured tire from the tire mold, applying each of the pair of sidewall-stabilizing run-flat inserts on a radially inner surface of a sidewall of the cured tire such that the at least one circumferential groove opens into a tire cavity of the cured tire and a first terminating end of each of the pair of sidewall-stabilizing run-flat inserts terminates above a bead core and a second terminating end, radially opposite the first terminating end, terminates along at least one of the sidewall and a respective adjacent shoulder. 
     In accordance with yet another feature of the present invention, the step of curing the green tire further includes a step of curing the green tire in the tire mold without a sidewall-stabilizing run-flat insert. 
     In accordance with another feature, an embodiment of the present invention also includes, before the step of applying the pair of sidewall-stabilizing run-flat inserts, forming the pair of sidewall-stabilizing run-flat inserts by at least one of injection molding and compression molding. 
     Although the invention is illustrated and described herein as embodied in a post-cure sidewall stabilizing reinforcement and method of manufacturing, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention. 
     Other features that are considered as characteristic for the invention are set forth in the appended claims. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. The figures of the drawings are not drawn to scale. 
     Before the present invention is disclosed and described, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The terms “a” or “an,” as used herein, are defined as one or more than one. The term “plurality,” as used herein, is defined as two or more than two. The term “another,” as used herein, is defined as at least a second or more. The terms “including” and/or “having,” as used herein, are defined as comprising (i.e., open language). The term “coupled,” as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The term “providing” is defined herein in its broadest sense, e.g., bringing/coming into physical existence, making available, and/or supplying to someone or something, in whole or in multiple parts at once or over a period of time. 
     As used herein, the terms “about” or “approximately” apply to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of skill in the art would consider equivalent to the recited values (i.e., having the same function or result). In many instances these terms may include numbers that are rounded to the nearest significant figure. In this document, the term “longitudinal” should be understood to mean in a direction corresponding to an elongated direction of the post-cure sidewall-stabilizing run-flat insert from an end closest to the tread to an opposing end closest to the bead. 
     As used herein, the terms “axial” and “axially” is intended to indicate lines or directions that are parallel to the axis of rotation of the tire. The terms “radial” and “radially” are defined as lines or directions radially toward or away from the axis of rotation of the tire. “Circumferential” means circular lines or directions extending along the surface of the sidewall perpendicular to the axial direction. The term “lateral” means an axial direction. The term “equatorial plane” (EP) is intended to indicate a plane perpendicular to the tire&#39;s axis of rotation and passing through the center of the tread. The acronym “psi” stands for pounds per square inch. “Normal inflation pressure” and “normal inflation condition,” as used herein, is defined as the specific design inflation pressure at a specified load assigned by the appropriate standards organization for the service condition for the tire. “Normal load,” as used herein, is intended to indicate the specific design inflation pressure and load assigned by the appropriate standards organization for the service condition for the tire. “Section height” (SH) means the radial distance from the nominal rim diameter to the outer diameter of the tire at its equatorial plane. The terms “zero psi,” “uninflated,” “underinflated,” “deflated,” and “run-flat condition” are used herein interchangeably to identify a condition in which the tire is operating under a loss of normal operating inflation pressure. The terms “post-cure sidewall-stabilizing run-flat insert,” “insert,” and “post-cure SSR insert” are used herein interchangeably to identify the inventive insert of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and explain various principles and advantages all in accordance with the present invention. 
         FIG. 1  is a cross-sectional view of a prior art run-flat tire with a sidewall-stabilizing insert disposed within a sidewall between an inner liner and a body ply; 
         FIG. 2  is a cross-sectional view of an exemplary embodiment of a pneumatic tire with a post-cure sidewall-stabilizing run-flat insert disposed on an inner surface of the sidewall, in accordance with the present invention; 
         FIG. 3  is a cross-sectional elevational side view of the pneumatic tire introduced in  FIG. 2  in a disassembled and assembled configuration, illustrating the post-cure sidewall-stabilizing run-flat insert applied to the inner surface of the sidewall, in accordance with the present invention; 
         FIG. 4  is a partially hidden side view, in a disassembled and assembled configuration, of the post-cure sidewall-stabilizing run-flat insert introduced in  FIG. 2  having a decoupling groove configuration, in accordance with the present invention; 
         FIG. 5  is a partial cross-sectional view of the pneumatic tire introduced in  FIG. 2  with the decoupling groove configuration during a normal inflation condition of the tire, in accordance with an exemplary embodiment of the present invention; 
         FIG. 6  a partial cross-sectional view of the pneumatic tire introduced in  FIG. 2  with the decoupling groove configuration, during a zero psi condition of the tire, in accordance with an exemplary embodiment of the present invention; 
         FIG. 7  a partial cross-sectional view of the pneumatic tire introduced in  FIG. 2  with the decoupling groove configuration, during a deflection of the tire in the normal inflation condition, in accordance with an exemplary embodiment of the present invention; and 
         FIG. 8  is a block diagram view of a process flow chart of an exemplary manufacturing process, in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. It is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. 
     Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. 
     The present invention provides a novel and efficient sidewall-stabilizing run-flat (SSR) insert that is applied to the interior surface of a sidewall of a cured tire. In addition, embodiments of such post-cure SSR insert may also extend continuously along a shoulder of the tire, but preferably not further than the shoulder. Embodiments of the invention provide for an injection molded or compression molded post-cure SSR insert with a unique geometric profile operably configured and adapted to improve the tire ride quality, while also maintaining a level of run-flat tire performance equal to industry standards. In additional embodiments, the post-cure SSR insert is disposed on the interior surface of the sidewall in the same orientation as a conventional cured-in SSR insert, which has been shown to carry vehicle loading at a zero psi loaded operating condition. Materials selected for the post-cure SSR insert (including composites), geometric configurations, reinforcing plys, and thickness of the post-cure SSR insert may be adjusted to suit particular design requirements. In some embodiments, the post-cure SSR insert may be formed with circumferential decoupling grooves/notches operably configured to improve ride quality during normal inflation conditions, while also providing sufficient self-supporting sidewall-stabilizing run-flat support during the zero psi state of the tire. 
     Referring now to  FIG. 2 , one embodiment of the present invention is shown in a cross-sectional view.  FIG. 2  shows several advantageous features of the present invention, but, as will be described below, the invention can be provided in several shapes, sizes, combinations of features and components, and varying numbers and functions of the components. The first example of a run-flat tire  200 , in accordance with the present invention, is shown in  FIG. 2 , and includes a main tire body  201  having a tread  202 , a belt structure  204 , a body ply  206 , a first and second exterior sidewall members  208  and  210 , an inner liner  212 , and a first and second bead portion  214  and  216 . In addition to the main tire body  201 , the inventive run-flat tire  200  also includes a pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220 . 
     The tread  202  includes a first end  222  and a second end  224  opposite the first end  222 . The tread  202  is a rubber compound on an outer portion of the run-flat tire  200  that comes into contact with a ground surface. In other words, “tread” refers to the portion of the tire that comes into contact with the road under a normal load. The tread  202  provides the grip or traction required for driving, braking, and cornering. The tread  202  may include one or more grooves, lugs, voids, and/or sipes that define the geometrical shape of the tread  202 . 
     The belt structure  204  can include at least one belt  204 , preferably at least two belts  204 . In one embodiment, the belt structure  204  is disposed radially outward of the body ply  206  and radially inward of the tread  202 . Stated another way, the belt structure  204  is disposed between the tread  202  and the body ply  206 . In another embodiment, the belt structure  204  includes two steel belt plies, each belt ply including steel parallel cords oriented at opposite angles to one another and disposed directly on top of the body ply  206 . The belt structure  204  is also commonly referred to as “stabilizer plies.” The belt structure  204 , i.e. stabilizer plies, is operably configured to restrict expansion of the body ply  206  cords, stabilize the tread area, and provide impact resistance. In one embodiment, the belt structure  204  is made of materials other than steel. In yet another embodiment, the belt structure  204  is made with three or more belt plies. In a further embodiment, the belt structure  204  is made of woven materials, instead of parallel-aligned cords. As used herein, the term “cord” is intended to indicate reinforcement strands of which the plies of a tire, and other components of a tire, are comprised of. The term “ply” is intended to indicate a layer with parallel cords. 
     In one embodiment, the run-flat tire  200  includes a single body ply  206 . In further embodiments, the run-flat tire  200  can include two or more body plies  206 . In yet another embodiment, the body ply  206  extends continuously from the first bead portion  214  to the second bead portion  216 . The body ply  206  is configured to provide strength to contain the air pressure and provide for sidewall impact resistance. In one embodiment, the body ply  206  includes parallel cords encapsulated in a rubber coating, also referred to in the art as “body ply skim.” In another embodiment, the body ply  206  extends radially across the run-flat tire  200 , wrapping around each of the first and second bead portions  214 ,  216 . Stated another way, the body ply  206  can be seen as including a main body ply portion  226 , a first turned-up portion  228 , and a second turned-up portion  230 , each of the turned-up portions  228 ,  230  extending from opposing ends of the main body ply portion  226 . The main body ply portion  226  can extend 360 degrees about the run-flat tire  200  in a continuous manner In one embodiment, the main body ply portion  226  is disposed between the tread  202  and the inner liner  212 . More particularly, at least a portion of the main body ply portion  226  can be disposed directly between the belt structure  204  and the inner liner  212 , where the belt structure  204  is disposed radially outward of the main body ply portion  226  and the inner liner  212  is disposed radially inward of the main body ply portion  226 . In some embodiments, cords of the body ply  206  may be made from, for example, polyester, nylon, rayon, steel, aramid, fiberglass, or any other suitable metal or textile. 
     In one embodiment, each of the first  228  and second turned-up portions  230  loops around the corresponding bead portion  214 ,  216 , respectively. In another embodiment, the first turned-up portion  228  includes a first end  232  and the second turned-up portion  230  includes a second end  234 , opposite the first end  232 . Stated another way, the first end  232  and the second end  234  can be considered opposite edges of the body ply  206 . In one embodiment, each of the first end  232  and the second end  234  terminates within a respective first and second sidewall. In another embodiment, each of the first end  232  and the second end  234  contacts a surface of the body ply  206  after looping around the respective bead portion  214 ,  216 . In a further embodiment, each of the first end  232  and the second end  234  contacts a radially outer surface of the body ply  206  after looping around the respective bead portion  214 ,  216 . In yet a further embodiment, the first turned-up portion  228  can be said to loop around the first bead portion  214  in a clockwise direction, while the second turned-up portion  230  loops around the second bead portion  216  in a counter-clockwise direction. 
     The run-flat tire  200  includes a first and second sidewall  207 ,  209  axially spaced apart from one another. The “sidewall” means a portion of the tire between the tread and the bead core. As used herein, the term “sidewall” is intended to encompass portions of the various conventional tire layers (e.g., exterior sidewall members, body plies, bead fillers, inner liner, etc.) that lay within the area between the tread and the bead core on respective sides of the of the tread. In one embodiment, each of the first and second exterior sidewall members  208 ,  210  is axially spaced apart from one another. Each exterior sidewall member  208 ,  210  can be said to extend from the respective bead portion  214 ,  216  to the respective tread end  222 ,  224 . In a preferred embodiment, the exterior sidewall members  208 ,  210  are made of a rubber material and are configured to protect the body ply  206  from abrasion, impact, and flex fatigue. In some embodiments, a radially outward surface of each the exterior sidewall members  208 ,  210  is exposed to and viewable from the outside environment and may also carry decorative treatments, including white or colored stripes or letters. Sidewall rubber compounds can be formulated to resist cracking due to environmental hazards, such as ozone, oxygen, UV radiation, and heat. 
     The inner liner  212  is disposed beneath the tread  202 . Said another way, the inner liner  212  is disposed radially inward of the tread  202 . The “inner liner,” as used herein, is intended to indicate a layer that forms an inner peripheral surface of a tubeless tire. In one embodiment, the inner liner  212  is a relatively thin, layer of elastomer, specially formulated to improve air retention by lowering permeation of air outwards through the tire  200 . In other embodiments, the inner liner  212  may be made of a different material. In most conventional tires, the inner liner  212  is considered the radially inner-most layer of the tire  200 . 
     In one embodiment, each of the pair of bead portions  214  is axially spaced apart from one another. In another embodiment, each of the pair of bead portions  214  includes a bead core  236  and a bead filler  238 . In some embodiments, the bead core  236  can be considered the portion of the tire that engages a rim on a wheel. In one embodiment, the bead core  236  includes individual bronze plated bead wires that are rubber coated and wound into a bundle of bead wires of a specified diameter and configuration, anchoring an inflated tire to a wheel rim. In some embodiments, the bead wire may be carbon steel wire. In other embodiments, the bead wire may be made of other metal materials. In another embodiment, the bead core  236  can be considered an annular inextensible member, holding a tire to the rim and being wrapped around by one or more body plies  206 . 
     The bead filler  238 , also known in the art as the apex, can be applied on top of the bead core  236  to fill a cavity formed between a radially inward portion of the body ply  206  and respective ends  232 ,  234  of the turned-up portions of the body ply  206 . In a preferred embodiment, the bead filler  238  is of a rubber material and may be formed so as to have a triangular cross-sectional shape. In some embodiments, the bead filler  238  is of a high durometer rubber material. In other embodiments, the bead filler  238  may include a low durometer rubber material. In yet other embodiments, the bead filler  238  may terminate within a plane (P) that lies in a central portion of the sidewall. As used herein, the term “central portion” is intended to indicate a middle section of the sidewall  207 ,  209  between a top section and a bottom section of the sidewall  207 ,  209 , where the middle section, the top section, and the bottom section are each one-third sections of the sidewall  207 ,  209 . 
     In yet another embodiment, the bead filler  238  extends radially from the bead core  236  to a distance of no more than 60% of the section height. In yet another embodiment, the bead filler  238  extends radially from the bead core  236  to a distance of no more than 50% of the section height. In yet a further embodiment, the bead filler  238  can be said to terminate at or beneath a plane that lies at a point about midway between the bead core  236  and the respective tread end  222 ,  224 . Varying the bead filler height and hardness can affect the tire&#39;s  200  ride and handling properties and may impact sidewall stiffness. 
     Still referring primarily to  FIG. 2 , each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  is disposed on a radially inner surface  240  of each respective sidewall  207 ,  209 . As used herein, the term “post-cure” is intended to indicate inserts that are applied to a tire after the green tire has been cured within a tire mold. An exemplary method of applying such post-cure SSR inserts is described herein below with reference to the flowchart in  FIG. 8 . 
     Each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  can be considered to extend along substantially an entire length of the respective sidewall  207 ,  209  on which the insert  218 ,  220  is disposed, but not substantially further than the entire length of the respective sidewall  207 ,  209 , during the normal inflation condition of the tire  200 . As used herein, the term “substantially” is intended to indicate 100% of a reference object or reference measurement (+/−15%). In other words, each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  extends along 100% of the entire length of the respective sidewall  207 ,  209  (+/−15% of the entire length). 
     Stated yet another way, each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  includes a first terminating end  242  and a second terminating end  244 , opposite the first terminating end  242 . For each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220 , the first terminating end  242  may terminate above the bead core  236  and the second terminating end  244  may terminate, beneath the tread  202 , along at least one of the respective sidewall  207 ,  209  and a respective adjacent shoulder  246 ,  248 . The “shoulder” means the portion of the tire where a lateral end of the tread transitions to the sidewall. 
     In one embodiment, the first terminating end  242  of each insert  218 ,  220  may terminate 0.5 inches above the bead core  236 , similar to the conventional SSR inserts. In an alternative embodiment, the first terminating end  242  of each insert  218 ,  220  may terminate more or less than 0.5 inches above the bead core  236 , but should still extend along a sufficient length of the sidewall  207 ,  209  so as to provide sidewall-stabilizing run-flat support in the zero psi state. 
     In one embodiment, the second terminating end  244  of each insert  218 ,  220  may be disposed so as to terminate along the respective sidewall  207 ,  209 . In an alternative embodiment, the second terminating end  244  of each insert  218 ,  220  may be disposed so as to terminate along the respective shoulder  246 ,  248 . In other words, each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  should be primarily disposed to extend along the respective sidewall  207 ,  209  similar to and in the same orientation as the conventional cured-in SSR inserts, except that the inserts  218 ,  220  of the present invention are applied to the radially inner surface  240  after the green tire is cured. Embodiments of the post-cure sidewall-stabilizing run-flat inserts  218 ,  220  of the present invention may also extend along the respective shoulder  246 ,  248 , but should not extend much further than that. The radially inner surface  240  of the sidewall  207 ,  209  can also be considered the radially inner surface  240  of the inner liner  212  of the run-flat tire  200 . 
     The inserts  218 ,  220  are preferably made of an elastomeric material, such as rubber, having a high degree of hardness/stiffness, yet a low hysteresis. The hysteresis of the elastomeric material is a measure of its tendency to generate internal heat under flexing service conditions. As is known in the art, hysteresis is a term for heat energy expended in a material (e.g., cured rubber composition) by applied work. Generally, a rubber or elastomeric material having a lower hysteresis generates less internal heat under service conditions than an otherwise comparable elastomeric or rubber with a substantially higher hysteresis. Thus, a relatively low hysteresis is desired for the rubber composition of the inserts  218 ,  220  because the tire&#39;s  200  life can be improved, especially during operation in a zero psi state. In one embodiment, the rubber compound of the inserts  218 ,  220  is the same or substantially similar to the rubber compound of the bead filler  238 , differing only with respect to the shape and placement within the tire  200 . 
     The material of the inserts  218 ,  220  may be selected from a wide range of elastomers having a shore A hardness of 50 to a very hard 85. In one embodiment, the material may be an elastomer with a shore A hardness of between 60 and 85. The inserts&#39;  218 ,  220  material composition, general shape, and/or thickness may, in some embodiments, be the same or similar to conventional cured-in SSR inserts, with the exception that the inserts&#39;  218 ,  220  are applied at a different stage in the manufacturing process and are disposed within a different area of the tire  200  than the conventional cured-in SSR inserts. In addition, some embodiments may provide the inserts  218 ,  220  with unique geometric cross-sections that differ from the conventional crescent-shaped cured-in SSR inserts. 
     The pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  should provide load-bearing, run-flat support in the zero psi state when disposed on the radially inner surface  240  of the run-flat tire  200  in accordance with the present invention. In one embodiment, the material composition of the inserts  218 ,  220  may provide a level of flexibility during normal inflation, load-bearing operating conditions so as to improve ride quality over traditional SSR run-flat tires, in addition to the sidewall-stabilizing, run-flat support in the zero psi state. In other embodiments, each of the inserts  218 ,  220  may be made of other polymer materials. In yet other embodiments, each of the inserts  218 ,  220  may also include other non-polymer materials that provide the inserts  218 ,  220  with desirable material properties, such as a durability, heat-resistance, etc. 
     Each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  can be considered to include an inner-liner facing surface  250  and a tire-cavity facing surface  252  opposite the inner-liner facing surface  250 . The “tire cavity”  251  means the area of the tire defined by the radially inner surfaces of the tire that is sealed by a rim of a wheel. The inner-liner facing surface  250  may also be considered the radially outer surface of the insert  218 ,  220  and the tire-cavity facing surface  252  may be considered the radially inner surface of the insert  218 ,  220 . The inner-liner facing surface  250  of each of the inserts  218 ,  220  is disposed on the radially inner surface  240  of the inner liner  212 . 
     Each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  may include a generally crescent-shaped cross-section, similar to cured-in SSR inserts. In preferred embodiments, the inserts  218 ,  220  have an irregular-shaped cross-section, as depicted in  FIGS. 2 and 5-7 . In one embodiment, the inserts  218 ,  220  may have a curved inner-liner facing surface  250  and a jagged, zizag, or polygonal-shaped tire-cavity facing surface  252  that provides ride quality improvements over cured-in SSR run-flat tires, as will be explained in more detail herein below, with reference to  FIGS. 5-7 . 
     In one embodiment, the inner-liner facing surface  250  is secured to the radially inner surface  240  of the inner liner  212  by an adhesive material  400  (see  FIG. 4 ). The adhesive material  400  may be considered a permanent or a semi-permanent adhesive material  400 . The adhesive material  400  should provide sufficient adhesion of the inserts  218 ,  220  to the radially inner surface  240  of the sidewall  207 ,  209  over the normal operational life of the tire  200 , as well as, sufficient adhesion to secure the inserts  218 ,  220  to the radially inner surface  240  during the zero psi state. In one embodiment, the adhesive material  400  may be a rubber gum. In a further embodiment, the adhesive material  400  may be a rubber gum that is similar to or identical to a cushion gum layer that is conventionally an uncured rubber-containing composition that, upon curing, mates new tread to the tire casing, during a retreading processes. The cushion gum layer is typically extruded in its uncured form and subsequently applied to the surface to be adhered. In another embodiment, the adhesive material  400  may be a rubber cement composition. In yet another embodiment, the adhesive material  400  may be formed as a spray-on or a painted-on adhesive. In yet other embodiments, the adhesive material  400  may be formed as other types of adhesive compositions. 
     In alternative embodiments, each of the post-cure sidewall-stabilizing run-flat inserts  218 ,  220  may be secured to the radially inner surface  240  of the inner liner  212  by other materials or structures. Importantly, each of the post-cure sidewall-stabilizing run-flat inserts  218 ,  220  should be secured to the radially inner surface  240  so as to not become detached from the main tire body  201  during normal tire use. 
     Referring now primarily to  FIG. 3 , the post-cure sidewall-stabilizing run-flat insert  218  is shown in a disassembled and assembled configuration with respect to the main tire body  201  and, more particularly, with respect to the radially inner surface  240  of the sidewall  207 , in a cross-sectional elevational side view of the run-flat tire  200 . Although  FIG. 3  depicts only one insert  218  and its corresponding sidewall  207 , it is understood that the other side of the tire  200  with the insert  220  disposed on the sidewall  209  is identically constructed, i.e. a mirror image. Accordingly, the following description should apply to the insert  220 , as well. 
     The post-cure sidewall-stabilizing run-flat insert  218  may extend continuously and circumferentially 360 degrees about a rotational axis  300  of the run-flat tire  200 . The main tire body  201  may be provided as a conventional non-run-flat tire. Accordingly, the post-cure sidewall-stabilizing run-flat inserts  218 ,  220  are operable to provide sufficient run-flat support, during a run-flat condition, without the additional support of prior art cured-in sidewall-reinforcing inserts  100   a,    100   b.  Stated yet another way, the inventive run-flat tire  200  of the present invention may be manufactured according to conventional non-run-flat manufacturing processes during the pre-cure portion of the manufacturing process. Yet, after the tire is cured, the post-cure sidewall-stabilizing run-flat inserts  218 ,  220  may be applied so as to provide run-flat capability to the conventional non-run-flat tire. Accordingly, a tire manufacturer employing a conventional pneumatic tire assembly process may not be required to deviate substantially from its tire assembly process. Such conventional tire manufacturer may maintain its current tire manufacturing processes while merely adding, for example, an additional station to apply the inserts after the tire curing process. 
     As is apparent from  FIG. 3 , the insert  218  is disposed primarily on the sidewall  207  of the tire  200 . As explained herein above, in some embodiments, nominal portions of the insert  218  may also extend into the respective adjacent shoulder  246 . In yet other embodiments, the insert  218  is restricted to a disposition on only the respective sidewall  207 . 
     Referring now primarily to  FIG. 4 , the post-cure sidewall-stabilizing run-flat insert  218  is shown in a disassembled and assembled configuration with respect to the main tire body  201 , in a partially hidden side view. More specifically, the post-cure sidewall-stabilizing run-flat insert  218  is shown being applied to the radially inner surface  240  of the respective sidewall  207  of the run-flat tire  200 , via the adhesive material  400 . As can be seen in the assembled configuration, the insert  218  may be secured to the sidewall  207  (by the adhesive material  400 ) between the bead area  236  and the tread  202 . 
     Referring now primarily to  FIGS. 4-6 , with brief reference to  FIG. 2 , one embodiment of the insert  218  may include at least a center rib  500  disposed between a first side rib  502  and a second side rib  504 . As explained above with respect to  FIG. 3 , although  FIG. 5  (as well as,  FIGS. 7 and 8 ) depict only one insert  218  and its corresponding sidewall  207 , it is understood that the other side of the tire  200  with the insert  220  disposed on the sidewall  209  is identically constructed, i.e. a mirror image. Accordingly, the following description herein should apply to the insert  220 , as well. In addition, although the following description describes primarily the center rib  500  and the side ribs  502  and  504 , it should be understood that there may be yet additional ribs in some embodiments, as can be seen in the figures. Accordingly, the description of the center rib  500  and the side ribs  502 ,  504  that follows herein can generally be considered to apply to any additional ribs, unless otherwise clearly indicated herein. 
     The ribs  500 ,  502 ,  504  may extend continuously in a circumferential direction 360 degrees about the rotational axis  300  of the tire  200 . The first side rib  502  and the second side rib  504  may be separated radially from the center rib  500  by a first decoupling groove  506  and a second decoupling groove  508 , respectively. It should be understood that use of the term “center” in the center rib  500  is intended to indicate that the rib  500  is disposed between the ribs  502  and  504  and should be interpreted in a broad sense of the word “center,” as not necessarily requiring equidistance of the center rib  500  from the side ribs  502  and  504 . Although, some embodiments may include the center rib  500  as equidistant from the side ribs  502  and  504 . 
     In one embodiment, the ribs  500 ,  502 ,  504  include a trapezoidal cross-section  254  ( FIG. 2 ). In another embodiment, the ribs  500 ,  502 ,  504  may include other cross-sections, such as, for example, triangular cross-sections, curved cross-sections, or other irregular polygonal-type cross-sections. In a preferred embodiment, the cross-sections of the ribs  500 ,  502 ,  504  should be configured such that the inserts  218 ,  220  form a solid sidewall-reinforcing support structure during the zero psi state (see  FIG. 6 ), while also permitting lateral and vertical displacement during the normal operating conditions of the tire (see  FIG. 7 ) so as to improve ride quality over conventional cured-in SSR inserts. In other words, in some embodiments, the tire-cavity facing surface  252  of each of the inserts  218 ,  220  is considered to extend zig-zag in a radial direction of the tire  200  during the normal inflation condition ( FIGS. 5 and 7 ) and extends along a continuous curvature ( FIG. 6 ) during an uninflated condition of the tire  200 . 
     In one embodiment, each of the ribs  500 ,  502 ,  504  includes substantially the same cross-section. In alternative embodiments, each of the ribs  500 ,  502 ,  504  may include cross-sections that are different from one another. In yet another embodiment, the center rib  500  includes a cross-section that is different from the side ribs  502 ,  504  and the side ribs  502 ,  504  have the same cross-section. 
     The decoupling grooves  506  and  508  can be considered to define the radially recessed transition from one of the ribs  500 ,  502 ,  504  to an adjacent rib  500 ,  502 ,  504 . The decoupling grooves  506  and  508  are circumferentially extending grooves/notches that allow displacement of the tire  200  in both the vertical direction, Y, and the horizontal direction, X for improving ride quality over cured-in SSR insert tires, and, preferably, for achieving a ride quality equal to or at least substantially equal to a conventional (non-run flat) passenger tire. As is known in the art, traditional cured-in SSR insert tires provide thicker sidewalls, typically of a high durometer rubber, that stiffens the sidewall. Unfortunately, while such cured-in SSR inserts provides load-bearing sidewall support during the zero psi state, the ride quality is negatively affected. Embodiments of the present invention improve the state of the art by providing a post-cure insert with a unique geometric configuration that increases the flexibility of the post-cure insert (over cured-in SSR inserts). 
     Each of the first and second decoupling grooves  506  and  508  are defined by two rib walls  510 ,  512  and  514 ,  516 , respectively, that form a continuous, circumferential groove  506 ,  508  extending 360 degrees about the rotational axis  300  (see  FIG. 3 ), during the normal inflation condition of the tire  200 . In a further embodiment, for each of the first and second decoupling grooves  506  and  508 , the corresponding rib walls  510 ,  512 ,  514 ,  516  are adapted to move toward one another during deflection of the tire in the normal inflation condition of the tire  200 , as illustrated in  FIG. 7 . Stated another way, the decoupling grooves  506  and  508  can become more narrow during deflection. This provides the flexibility of the post-cure SSR inserts  218 ,  220  to permit both vertical and lateral displacement that improves the ride quality. 
     During an uninflated condition of the tire, the rib walls  510 ,  512  and  514 ,  516  collapse in on each other so as to close the continuous circumferential groove  506  and  508 , respectively, as depicted in  FIG. 6 . To elaborate, the decoupling grooves  506  and  508  are configured to close completely at a vertical displacement, Y′, and a lateral displacement, X′, that typically results from a zero psi state of the tire  200 . The decoupling grooves  506  and  508 , in this closed-off configuration, dynamically form a solid sidewall-stabilizing reinforcing support structure to carry the load of the vehicle during the zero psi state of the tire  200 . 
     Each of the first and second decoupling grooves  506  and  508  can be considered to open into the tire cavity  251  during the normal inflation condition of the tire  200  ( FIGS. 5 and 7 ) and is dynamically closed-off from the tire cavity  251  during the uninflated condition of the tire  200  ( FIG. 6 ). 
     Each of the first and second decoupling grooves  506  and  508  defines a groove cross-section  256  ( FIG. 2 ). In a further embodiment, the groove cross-section  256  is formed as a generally V-shaped groove cross-section. As used herein, the term “generally V-shaped groove cross-section” is intended to be interpreted broadly to include groove cross-sections defined by opposing walls oriented away from one another, whether or not the opposing walls meet at a common end point (e.g., includes trapezoidal-shaped cross-sections). In alternative embodiments, the decoupling grooves  506 ,  508  may define groove cross-sections  256  having other shapes and configuration, such as, for example, concave grooves, curved grooves, and irregular shaped grooves. Importantly, the decoupling grooves should be operable to permit lateral and vertical displacement so as to improve ride quality of the run-flat tire  200 . In one embodiment, each of the decoupling grooves  506 ,  508  defines substantially the same cross-section. In alternative embodiments, each of the decoupling grooves  506 ,  508  may define cross-sections that are different from one another. 
     In one embodiment, each of the pair of post-cure sidewall-stabilizing run-flat inserts  218 ,  220  further includes a third side rib  518  and a fourth side rib  520 . The third and fourth side ribs  518  and  520  may be separated radially from the first and second side ribs  502  and  504  by a third decoupling groove  522  and a fourth decoupling groove  524 , respectively. The third and fourth side ribs  518  and  520  may be disposed outwardly from the center rib  500 , as well as, the first and second side ribs  518  and  520 . 
     Referring now primarily to the process flow chart depicted in  FIG. 8 , with reference to  FIG. 2 , an exemplary method of manufacturing the tire  200  of the present invention is described. Although  FIG. 8  shows a specific order of executing the process steps, the order of executing the steps may be changed relative to the order shown in certain embodiments. Also, two or more blocks shown in succession may be executed concurrently or with partial concurrence in some embodiments. Certain steps may also be omitted in  FIG. 8  for the sake of brevity. In some embodiments, some or all of the process steps included in  FIG. 8  can be combined into a single process. 
     The exemplary process may begin at step  800  and immediately proceed to step  802 , where each of the post-cure SSR inserts  218 ,  220  is formed by at least one of injection molding and compression molding. Advantageously, the injection molding or compression molding of the post-cure SSR inserts  218 ,  220  provides for a myriad amount of design possibilities, primarily due to the fact that the inserts  218 ,  220  may not be bound by the limitations of current extrusion and tire assembly processes. 
     In step  804 , after the post-cure SSR inserts  218 ,  220  are formed in step  802 , a green tire is provided in a tire mold. In one embodiment, before the green tire is placed in the tire mold, the green tire may be formed by individually applying tire components at a tire building machine (TAM) with a tire building drum, as disclosed by U.S. Pat. No. 6,488,797, incorporated herein by reference. In one embodiment, the green tire that is formed at the TAM and provided in the tire mold is a run-flat tire with a sidewall-reinforcing insert. In such embodiments, the post-cure run-flat inserts  218 ,  220  may provide additional run-flat support. 
     In a preferred embodiment, the green tire that is formed at the TAM and subsequently placed in the tire mold for curing is a conventional non-run-flat tire, without a sidewall-reinforcing insert. In such embodiments, the post-cure run-flat inserts  218 ,  220  are configured so as to provide run-flat support for the conventional non-run-flat tire. Accordingly, conventional non-run-flat tire manufacturing processes can be used to construct the tire  200  pre-cure; yet, after the green tire is cured run-flat support can be provided via placement of the post-cure run-flat inserts  218 ,  220  on the cured tire. 
     In step  806 , the green tire is cured in the tire mold, per normal tire manufacturing curing processes and equipment. In step  808 , the cured tire is removed from the tire mold. After removing the cured tire from the tire mold, in step  810 , the adhesive material  400  may be applied to the radially inner surface  240  of the sidewalls  207 ,  209  and/or the inner-liner facing surface  250  of each of the pair of post-cure inserts  218 ,  220 . In alternative embodiments, the post-cure inserts  218 ,  220  may be secured to the tire  200  by other materials or structures. 
     In step  812 , after the cured tire is removed from the tire mold, the post-cure inserts  218 ,  220  may be disposed on the radially inner surface  240  of the sidewalls  207 ,  209  so as to extend circumferentially along the sidewalls  207 ,  209 . The process may immediately end at step  814 . 
     A novel and efficient post-cure tire insert has been disclosed that can be applied after a green tire is cured and may provide post-cure run-flat support and/or also improve tire ride quality over conventional cured-in SSR inserts.