Abstract:
A method of assembling a tire having one or more reinforcements or supporting inserts in the sidewalls is provided. The reinforcements are positioned onto one or more air impermeable layers. One or more reinforcing plies are positioned over the reinforcing supports and suspended therebetween. A gas pressure is used to expand the one or more air impermeable layers away from the forming drum and against a reinforcing ply. As such, the creases or wrinkles in the one or more reinforcing plies can be avoided along with other non-uniformities such as deradialization and/or an uneven overlap where the ends of a ply are joined.

Description:
FIELD OF THE INVENTION 
       [0001]    The subject matter of the present disclosure relates generally to method of adhering the inner liner of a tire to a reinforcing ply. 
       BACKGROUND OF THE INVENTION 
       [0002]    Tires are commonly manufactured using of one or more building drums upon which the tire is constructed from multiple layers and components that are placed sequentially onto the drum. For example, in one technique, a layer of air impermeable rubber is laid onto the forming surface of a cylindrical drum. One or more carcass plies are placed onto the drum. A pair of circular beads are placed on opposing sides and may include bead wires and bead fillers. The plies are turned up and the beads are moved towards each other to create a toroidal shape. A sidewall protective rubber and a tread portion are added. 
         [0003]    The addition of rubber elements into the sidewalls of the tire can be desirable for certain tire applications. For example, the addition of rubber reinforcements into the sidewalls can be used along with other features to provide a tire that is capable of operating for a limited distance after losing inflation pressure. Such may allow the driver to reach a service center or other location more suitable than where the pressure loss occurred. 
         [0004]    Certain challenges, however, are presented in the manufacture of tires having e.g., reinforcement in the sidewalls. The forming drum is a typically a cylindrical shape having a flat profile along the axial direction but may have recesses for accepting features such as circular beads. For designs where these reinforcements are presented onto the forming drum before a carcass ply or reinforcing ply is laid onto the forming drum, the reinforcements create a profile that is no longer flat along the axial direction of the drum. Presentation of a carcass ply onto this uneven profile can result in undesirable creases or wrinkles—particularly when attempting to press the carcass ply towards the forming drum to make contact with e.g., an air impermeable layer on the forming drum. In turn, these creases can lead to an undesirable orientation and positioning of cords and/or other reinforcing elements present in the reinforcing ply—referred to herein as deradialization. Also, the joining of the ends of the ply may no longer be uniform as the amount of overlap may be quite variable. 
         [0005]    Accordingly, a method for assembling a tire having one or more reinforcements or supports in the sidewalls would be useful. More particularly, such a method that can be used to reduce or avoid creases or wrinkles that can lead to deradialization and/or non-uniformities in the joining of the ends of the plies would be beneficial. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides a method of assembling a tire having one or more reinforcements or supporting inserts in the sidewalls. The reinforcements are positioned onto one or more air impermeable layers. One or more reinforcing plies are positioned over the reinforcing supports and suspended therebetween. A gas pressure is used to expand the one or more air impermeable layers away from the forming drum and against a reinforcing ply. As such, the creases or wrinkles in the one or more reinforcing plies can be avoided along with other non-uniformities such as deradialization and/or an uneven overlap where the ends of a ply are joined. Additional objects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
         [0007]    In one exemplary aspect, the present invention provides a method of assembling tire components on a tire building drum having a cylindrically-shaped forming surface extending between opposing sides of the drum. The drum defines axial and circumferential directions. The method comprises the steps of laying one or more air impermeable layers onto the forming surface; positioning a pair of sidewall support inserts onto the one or more air impermeable layers with each sidewall support insert spaced from a respective side of the drum; placing at least one reinforcing ply over the pair of sidewall support inserts on the drum so as to suspend over the forming surface the at least on reinforcing supply between the pair of sidewall support inserts, wherein the at least one reinforcing ply comprises a plurality of perforations centrally positioned on the at least one reinforcing ply and spaced apart along a circumferential direction of the drum; stitching the at least one reinforcing ply to the pair of sidewall support inserts and to the one or more air impermeable layers at locations axially outward of each sidewall support while leaving the reinforcing supply suspended between the pair of sidewall support inserts; depositing a pair of bead fillers onto the at least one reinforcing ply with each bead filler spaced from a side of the drum; locating a pair of circular bead elements onto the drum with each bead element positioned onto the at least one carcass ply; turning up edges of the at least one reinforcing ply over the pair of bead fillers and the pair of bead elements; delivering a gas pressure to the surface of the forming drum so as to separate the one or more air impermeable layers from the forming surface at locations between the bead elements; moving the bead elements toward each other along the axial direction of the drum during the step of delivering a gas pressure; and using the gas pressure to push the one or more air impermeable layers against the at least one reinforcing ply. 
         [0008]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
           [0010]      FIGS. 1 through 8  illustrate certain steps of an exemplary method of the present invention as may be used for assembling a tire. For  FIGS. 1 through 7 , each figure shows a cross-sectional view of certain components of an exemplary tire as presented to a tire building or forming drum.  FIG. 8  illustrates a perspective view of a building drum onto which certain components of an exemplary tire have been placed. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    For purposes of describing the invention, reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0012]    An exemplary method of the present invention is illustrated through various steps shown in  FIGS. 1 through 8  as will now be described. Beginning with  FIG. 1 , a tire building drum  100  is shown. Drum  100  has a cylindrically-shaped forming surface  101  that extends between opposing sides  102  and  104  and is substantially flat along the axial direction A and curved along circumferential direction C ( FIG. 8 ). Drum  100  is rotatable so as to allow various components to be presented onto the forming surface  101  in the construction of a tire. Drum  100  may include various internal features for positioning components placed onto surface  101 . 
         [0013]    Initially, an air impermeable layer  106  (also referred to as an “inner liner”) is placed onto forming surface  101  in a generally centered position between sides  102  and  104  as shown. While only one layer is illustrated, it should be understood that one or more air impermeable layers may be used. A pair of sidewall support inserts  108  and  110  are positioned onto the air impermeable layer  106 . Each insert is placed at a predetermined distance from the sides  102  and  104  of drum  100  in an opposing manner and are generally equally spaced about center line C/L. The shape and size of the inserts is provided by way of example only and other configurations may be used. Additionally, while only a pair of inserts  108  are shown, more than one pair may be used to e.g., increase the sidewall strength of the assembled tire. 
         [0014]    A first reinforcing ply  112  and a second reinforcing ply  114  are placed onto the sidewall support inserts  108  and  110 . While two plies  112  and  114  are shown in the figures, using the teachings disclosed herein it will be understood that a single reinforcing ply or more than two reinforcing plies may also be used. Additionally, where multiple reinforcing plies are used, such plies do not have to be applied over drum  100  at the same time. 
         [0015]    Plies  112  and  114  contain multiple cords and/or other reinforcing features that constrain the assembled tire while making plies  112  and  114  generally stiff and substantially non-expandable. As such, attempts to press plies  112  and  114  into contact with air impermeable layer  106  between inserts  108  and  110  can create creases as previously discussed. Accordingly, for this exemplary method of the present invention, plies  112  and  114  are placed onto sidewall support inserts  108  and  110  and are suspended over the forming surface  101  between the inserts  108  and  110 . This creates a temporary cavity  116  extending circumferentially about drum  100  between air impermeable layer  106  and reinforcing ply  112 . 
         [0016]    Each reinforcing ply includes a plurality of perforations along the circumferential direction. More particularly, as shown in  FIG. 8 , reinforcing ply  112  includes a plurality of perforations  126  (e.g., holes or openings) that are spaced apart along circumferential direction C. In one exemplary embodiment of the invention, each perforation  126  has a diameter in the range of about 2 mm to about 4 mm. In another exemplary embodiment, each perforation  126  has a diameter of about 3 mm or, for example, 3 mm±0.5 mm. 
         [0017]    Additionally, for the exemplary embodiment illustrated, each perforation  126  is centrally positioned on reinforcing ply  112 . In other embodiments, perforations  126  should be located in the crown region of the tire. For example, in one exemplary embodiment, perforations  126  are within a range of about 0 to about 10 mm from centerline C/L. In another exemplary embodiment, perforations  126  are positioned on or within ±0.5 mm of centerline C/L. Other placements may be used, provided perforations  126  are located in the crown region of the tire. Similar perforations are provided in reinforcing ply  114 . A variety of techniques may be used to create perforations  126  in plies  112  and  114  as will be understood by one of skill in the art. The perforations can be created before plies  112  and  114  are applied are created as plies  112  and  114  are pulled onto drum  100 . 
         [0018]    It is not necessary for the perforations in the reinforcing plies  112  and  114  to be aligned with each other. Also, while two plies  112  and  114  are shown, other constructions may also be used including a single reinforcing ply or more than two plies  112  and  114 . In still another alternative, other components may be added between the application of reinforcing ply  112  and reinforcing ply  114 . For example, reinforcing ply  112  may be positioned onto inserts  108  and  110 . Other features such as e.g., additional sidewall reinforcement inserts may then be positioned into reinforcing ply  112  at positions axially outward of inserts  108  and  110  followed by the positioning of reinforcing ply  114  over or onto the same. 
         [0019]    Referring now to  FIG. 2 , reinforcing plies  112  and  114  are stitched against inserts  108  and  110  as well as air impermeable layer  106  as shown. More specifically, plies  112  and  114  are pressed towards the forming surface  101  at zones ST—which include inserts  108  and  110  and locations axially outward of inserts  108  and  110  as shown. This stitching leaves a portion of the plies  112  and  114 —designated as zone SU in FIG.  2 —suspended over layer  106  between the radially outermost portion of inserts  108  and  110  so that cavity  116  remains. 
         [0020]    A pair of bead fillers  122  and  124  as well as pair of circular bead elements  118  and  120  are positioned onto reinforcing ply  114  as shown in  FIG. 3 . The shape and size of bead fillers  122  and  124  are provided by way of example only and other configurations may be used. Additionally, while only a pair of bead fillers  122  and  124  are shown, each filler may be constructed from one or more pieces in alternative embodiments of the invention. Each bead filler  122  and  124  and bead  118  and  120  is positioned axially outward of a respective sidewall support insert  108  and  110 , respectively. 
         [0021]    Referring now to  FIGS. 3 and 4 , the ends  119  and  121  of the reinforcing plies  112  and  114  are turned up and over bead fillers  122  and  124  and circular bead elements  118  and  120  as indicated by arrows T. Several mechanisms can be used to turn up ends  119  and  121 . By way of example, forming surface  101  can be provided with pneumatically powered segments that can be inflated to lift portions of surface  101  and turn ends  119  and  121  over as shown. Other mechanisms may be used as well. 
         [0022]    In  FIG. 5 , a gas pressure (e.g., air) is delivered to the forming surface  101  of drum  100  so as to separate air impermeable layer  106  from surface  101 . For example, small passages may be provided in drum  100  to supply a gas to the forming surface  101 . As this gas is pressurized, air impermeable layer  106  will separate from forming surface  101  along the portion between bead elements  118  and  120  as shown. At the same time as this gas pressure is delivered, features associated with drum  100  (not shown) are activated such that bead elements  118  and  120  are moved towards each other or axially inward as shown by arrows M. Such drum features may be activated so as to initiate the movement of bead elements  118  and  120  towards each other at the same time the delivery of the gas pressure is initiated. Alternatively, a predetermined interval of time may be allowed to lapse after initiating delivery of the gas pressure before initiating movement of the bead elements  118  and  120  towards each other using features of drum  100 . 
         [0023]    As shown in  FIG. 6 , while the delivery of the pressurized gas from drum  100  continues, air impermeable layer  106  will eventually contact reinforcing ply  112 . The force of gas pressure P against air impermeable layer  106  and the movement of bead elements  118  and  120  (along with bead fillers  122  and  142  and ends  119  and  121 ) axially inward will cause reinforcing plies  112  and  114  to arch slightly. Plies  112  and  114 , anchored by bead elements  118  and  120 , will counteract the force provided by air pressure P through gas impermeable layer  106 . More particularly, the flexibility of layer  106  allows it to stretch to reach plies  112  and  114 . Conversely, the relatively inflexible properties of reinforcing plies  112  and  114  allows air impermeable layer  106  to be forced against and simultaneously supported by plies  112  and  114 . In addition, the perforations in plies  112  and  114  allow gas in cavity  116  to escape as air impermeable layer  106  moves towards plies  112  and  114  between e.g., the position shown in  FIG. 5  and the position shown in  FIG. 6 . 
         [0024]    As the air pressure is maintained against air impermeable layer  106  and bead elements  118  and  120  are moved axially inward towards each other, the intermediate tire assembly  130  takes on a toroidal shape as shown in  FIG. 7 . Protective sidewall rubber members (not shown) can be added to side wall portions  128  and  130 . A tread rubber (not shown) can be added to crown portion  132 . The resulting intermediate tire assembly  132  can then be removed from forming drum  100  and placed into e.g., a curing press for molding and curing. 
         [0025]    While the present subject matter has been described in detail with respect to specific exemplary embodiments and methods thereof; it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art using the teachings disclosed herein.