Abstract:
A tire assembly is disclosed, wherein the tire has a tread portion and a pair of sidewalls extending radially inward from the tread portion to join with a respective bead; a supporting carcass for the tread portion and sidewalls; and a pump passageway positioned within a bending region of the tire. The pump passageway is operative to open and close as the tire rotates. The tire assembly further includes a valve assembly in fluid communication with the pump passageway. The tire further includes a pocket formed in the tire, and a filter assembly is mounted in the pocket. The filter assembly is in air flow communication with the valve assembly, wherein the filter assembly is formed of a housing and a cover, wherein the cover has one or more holes for communicating air into the housing, wherein the cover is connected to the housing, the housing having an interior cavity having a filter media housed therein, the housing having a hole in fluid communication with the valve assembly, wherein a flexible collar surrounds the cover.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to tires and more specifically, to an air maintenance assembly for a tire. 
       BACKGROUND OF THE INVENTION 
       [0002]    Normal air diffusion reduces tire pressure over time. The natural state of tires is under inflated. Accordingly, drivers must repeatedly act to maintain tire pressures or they will see reduced fuel economy, tire life and reduced vehicle braking and handling performance. Tire Pressure Monitoring Systems have been proposed to warn drivers when tire pressure is significantly low. Such systems, however, remain dependent upon the driver taking remedial action when warned to re-inflate a tire to recommended pressure. It is a desirable, therefore, to incorporate an air maintenance feature within a tire that will maintain correct air pressure within the tire without a need for driver intervention to compensate for any reduction in tire pressure over time. It is useful to incorporate a filter in the design of an air maintenance tire system, so that the outside air is filtered. It is also useful to incorporate a regulator in the design to admit air into the system only when needed. The filter and regulator must be secured to the tire, and be able to sustain rotational forces. These devices must also be assembled in such a way to minimize the stresses in the tire and allow for ease of assembly. 
       SUMMARY OF THE INVENTION 
       [0003]    The invention provides in a first aspect an air maintenance tire and pump assembly including a tire having two spaced inextensible beads; a ground contacting tread portion; a pair of individual sidewalls extending radially inward from the axial outer edges of said tread portion to join the respective beads; a supporting carcass for the tread portion and sidewalls; an innerliner disposed radially inward of the carcass, the innerliner having a innerliner surface facing an interior cavity of the tire. A pump passageway is enclosed within a bending region of the tire, the pump passageway operatively closing and opening segment by segment as the bending region of the tire passes through a rolling tire footprint to pump air along the air passageway. A regulator device is in fluid communication with the pump passageway, the regulator device operable to regulate the fluid from outside of the tire into the pump passageway, the air inlet port assembly comprising a regulator assembly, the regulator device having a mounting surface coated with rubber. The mounting surface is adhered to the innerliner surface with a suitable adhesive. 
         [0004]    The invention provides in a second aspect a method for making an air maintenance tire and pump assembly. First, a green tire is provided, wherein a pocket is molded in the sidewall of the tire, wherein the pocket has a hole extending though the side of the tire into the tire cavity. A groove is also molded in the sidewall of the tire, and then the tire is cured. A green rubber patch is then coated on both sides with rubber cement and inserted into the pocket. Next a filter housing is affixed to the green rubber patch and then cured. Next filter media is inserted into the filter housing and then a cover is secured to the filter housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The invention will be described by way of example and with reference to the accompanying drawings in which: 
           [0006]      FIG. 1  is a front view of tire and rim assembly with a pump, valve and filter assembly. 
           [0007]      FIG. 2  is a cross sectional view of a truck tire having a groove in the bead area of the tire; 
           [0008]      FIG. 3  is a close up cross-sectional view of the truck tire bead area of  FIG. 2  illustrating the pump passageway; 
           [0009]      FIG. 4  is a close up cross-sectional view of the truck tire bead area illustrating a filter pocket; 
           [0010]      FIG. 5  is a front view of a filter pocket shown in the bead area of the tire; 
           [0011]      FIG. 6  is an exploded view of a filter assembly and tire bead area; 
           [0012]      FIG. 7  is a cross-sectional view of the portion of the tire illustrating the filter assembly in the pocket of the tire bead area; 
           [0013]      FIG. 8  is a front view of the filter assembly installed in the tire; 
           [0014]      FIG. 9  is a front perspective view of the filter assembly; 
           [0015]      FIG. 10  is a side cross-sectional view of the filter assembly. 
           [0016]      FIG. 11  is a perspective view of the filter housing. 
           [0017]      FIG. 12  is a cut away view of the filter housing. 
           [0018]      FIGS. 13-15  are perspective views of a second embodiment of a filter housing. 
           [0019]      FIG. 16  is a partial view of a tire mold showing the pocket mold mounted in the mold ring of the tire mold; and 
           [0020]      FIG. 17  is a perspective view of the pocket mold subassembly. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring to  FIGS. 1 and 2 , a tire assembly  10  includes a tire  12 , a pump assembly  14 , and a tire wheel  16 . The tire mounts in a conventional fashion to a wheel having rim mounting surfaces  18  located adjacent outer rim flanges  22 . An annular rim body  28  joins the rim flanges  22  and supports the tire assembly as shown. The tire is of conventional construction, having a pair of sidewalls  32  extending from opposite bead areas  34  to a crown or tire tread region  38 . The tire and rim enclose an interior tire cavity  40  which is filled with air. 
         [0022]    As shown in  FIGS. 1 and 3 , the tire assembly includes a pump  14  having a pump passageway  42  that is mounted or located in the tire in a channel  44 , preferably near the bead region  34  of the sidewall. The pump passageway  42  may be formed of a discrete tube made of a resilient, flexible material such as plastic, elastomer or rubber compounds, and is capable of withstanding repeated deformation cycles when the tube is deformed into a flattened condition subject to external force and, upon removal of such force, returns to an original condition. The tube is of a diameter sufficient to operatively pass a volume of air sufficient for the purposes described herein and allowing a positioning of the tube in an operable location within the tire assembly as will be described. Preferably, the tube has an elliptical cross-sectional shape, although other shapes such as round may be utilized. 
         [0023]    The pump passageway itself may also be integrally formed or molded into the sidewall of the tire during vulcanization, eliminating the need for an inserted tube. An integrally formed pump passageway is preferably made by building into a selected green tire component such as a chafer, a removable strip made of wire or silicone. The component is built into the tire and cured. The removable strip is then removed post cure to form a molded in or integrally formed pump air passageway. 
         [0024]    Hereinafter, the term “pump passageway” refers either to installed tubes or an integrally molded in passageway. The location selected for the pump passageway within the tire may be within a tire component residing within a high flex region of the tire, sufficient to progressively collapse the internal hollow air passageway as the tire rotates under load thereby conveying air along the air passageway from the inlet to the pump outlet. 
         [0025]    The pump air passageway  42  has an inlet end  42   a  and an outlet end  42   b  joined together by a valve system  200 , as shown in  FIGS. 6-7 . Examples of pressure regulators or valve systems suitable for use with the invention are disclosed in U.S. patent application Ser. Nos. 13/221,231, 13/221,433, 13,221,506 which are hereby incorporated by reference. As shown in this particular example, the inlet end  42   a  and the outlet end  42   b  are spaced apart approximately 360 degrees forming an annular pump assembly. However, the inlet and outlet ends may be spaced apart 90 degrees, 180 degrees, etc. 
         [0026]    The valve assembly  200  is preferably affixed to the inside of the tire, near the bead area. The valve assembly  200  has an inlet port  202  that is in fluid communication with a central air conduit  204 . The central air conduit  204  is in fluid communication with an air filter assembly  300 , as shown in  FIGS. 6-8 . The central air conduit is preferably a flexible tube or passageway that extends from a filter housing to the inlet port  202  of the valve assembly  200 . 
         [0027]    The valve assembly  200  is operable to control the amount of inlet air to the pump system  42 . If the tire cavity pressure falls below a set trigger pressure, the valve device allows air to enter the valve assembly  200  through inlet port  202 , and then through to the pump passageway  42 . The valve assembly may allow airflow into the pump system through an air inlet port  210 . The valve assembly also may control the flow of air from the pump into the tire cavity, as well as prevent cavity air from back flowing into the pump passageways. 
         [0028]    The air filter assembly  300  is positioned on the outer sidewall of the tire, in the vicinity of the pump passageways, as shown in  FIGS. 6-8 . The air filter assembly filters the outside air and communicates the filtered air to the inlet port  202  of the valve assembly  200 . The air filter assembly  300  has a housing  304 , and a cover  306  which assemble together to form an internal cavity  308 . The filter housing  304  is shown in  FIGS. 7 ,  10 ,  11 , and  12 . The filter housing  304  is also preferably elliptical in shape, with the minor axis aligned with the radial direction of the tire. The bottom surface  310  of the filter housing has a hole  312  for reception of a first end of the central air conduit  204 . The filter housing has a sidewall  314  having cutouts  316 . Tabular ends  320  of the cover  306  are received in the cutouts  316  to attach the cover to the filter housing. The front face of the cover has one or more holes  322 . The filter housing  304  and cover  306  may be made of hard plastic or metal. 
         [0029]    One or more layers of filter media  600  is received in the internal cavity  308  of the filter assembly  300 . The filter media may be a woven or nonwoven fiber, foam, spun fiberglass, charcoal, or other materials known to those skilled the art. Alternatively, a membrane such as PTFE GoreTex may be used, alone or in combination with the filter media. 
         [0030]    The air filter assembly  300  is mounted in a pocket  400  formed on the outer surface of the tire, typically in the sidewall area near the pump passageways. The pocket  400  is shown in  FIGS. 4-6 . The pocket may be molded in the tire during vulcanization using a conventional mold with an adaptor piece to form the pocket (not shown). The pocket may be molded in the tire during vulcanization as follows.  FIG. 13  illustrates a typical mold  20  used for molding and vulcanizing a green tire. The mold assembly typically comprises a plurality of segments  220  which are arranged to form an annular ring to encircle the tread of a green tire when the segments are assembled together. The outer tread surface of a tire is formed by the inner molding surface  24  of the segments  220 . A sidewall plate  26  is used to mold the sidewalls  32  of the tire. Adjacent the sidewall plate  26  is a mold ring  29  that molds the inner bead region of the tire. As shown in  FIG. 14 , a section of the mold ring  29  has a cutout portion  51  for receiving a pocket mold  50 . The pocket mold  50  may be secured to the mold ring  29  via bolts  30 . The pocket mold  50  forms the pocket  400  in the tire sidewall area. Alternatively, the sidewall plate  26  may also be used to install the pocket mold  52 , depending on the desired location of the filter assembly. As shown in  FIG. 14 , the pocket mold  50  forms or molds an elliptically shaped pocket  400  into the tire sidewall bead area, and the barb  53  of the pocket mold forms the passageway  406  through the tire sidewall. The pocket mold has wings  52  located on either side of the pocket  400 . The wings  52  form the slots  716 , 718  that are used to house the pump tubes  702 , 703 . Barbs  54  on the pocket mold form holes  704 , 706  that extend completely through the tire sidewall. 
         [0031]    Alternatively, the pocket may be formed in a vulcanized tire, post cure by laser cutting. As shown in  FIG. 5 , the general shape of the pocket  400  is curved, with no corners to eliminate stress concentrations. It is preferred that the pocket is also elliptical in shape, with the minor axis of the ellipse aligned with the radial direction of the tire. The pocket may also be round. The depth of the pocket is about 5-15 mm, and the major axis width is about 20-40 mm, minor axis width is about 8-15 mm. The pocket has a bottom surface  402  having a hole  404  that is connected to a passageway  406  formed through the tire to the tire cavity, so that fluid may communicate from the hole  404  in the pocket to the passageway exit  408 . An optional central air conduit  204  is positioned in the passageway  406  to communicate filtered air to the valve assembly  200 . Alternatively, the passageway  406  may be used to communicate fluid to the cavity from the pocket. 
         [0032]    The bottom surface  402  of the pocket may further optionally include molded in attachment knobs  416  as shown in  FIG. 10 . The attachment knobs  416  may be used to secure a filter housing to the pocket. The bottom of the filter housing may have recesses  418  which allow the knobs  416  to snap inside, as shown in  FIG. 10 . Alternatively, the filter housing may have knobs (not shown) which are secured into recesses of the pocket (not shown). 
         [0033]    The pocket  400  further includes a sidewall  410 . The sidewall  410  is surrounded by a first and second ledge  412 , 414  joined together. A flexible collar  500  has an interior hole  502  wherein the interior hole is positioned around the outer circumferential edge  307  of the cover  306 . The flexible collar  500  has a second end positioned on the first ledge  412 . Alternatively, the second end may be positioned in a slot  510  formed in the sidewall of the pocket, as shown in  FIG. 10 . The cross-sectional profile  512  of the flexible collar may be U shaped. The flexible collar allows for the ±10% sidewall strain seen in tire service while protecting the filter media from flexing. The flexible collar  500  is made from a flexible material such as rubber. 
         [0034]    A green (unvulcanized) rubber ring  600  has an inner hole that is positioned about the outer circumference of the flexible collar  500  and wherein the outer portion of the rubber ring is positioned on the second, outer ledge  414 . The green rubber ring  600  has an inner side which is coated with a suitable adhesive as described below. The green rubber ring  600  is then cured over the flexible collar and affixed to the sidewall of the tire. The green rubber ring  600  may be cured by heat. 
         [0035]    As shown in  FIGS. 7 and 10 , the filter housing major axis dimension and minor axis dimension is smaller than the pocket internal cavity  308 , such that there is a gap surrounding the filter housing. The spatial gap can be in the range of 2 mm to about 8 mm. 
         [0036]    In order to affix the filter assembly to the tire, the following steps are followed. First, the bottom and sides of the filter housing are buffed with abrasive material such as sandpaper. Next the bottom and sides of the filter housing are pretreated with Chemlock or other suitable adhesive. Preferably, the filter housing is placed in a mold and rubber is injection molded to enrobe the housing bottom and sides of the filter housing with rubber or elastomer. See  FIGS. 13-15  which illustrate the enrobed filter housing  900  with a coating  902  of green rubber or elastomer. The type of rubber suitable for use is known to those skilled in the art as cushion gum, however any type of rubber would work. The coating of rubber  902  may be cured or partially cured about the housing. 
         [0037]    Next, the pocket bottom surface  402  is buffed. As shown in  FIG. 6 , a green rubber patch  1000  is used to secure the filter housing to the tire pocket bottom surface. The green rubber patch  1000  is buffed on both sides. The rubber patch  1000  is then coated with a suitable adhesive on both sides and then inserted onto the pocket bottom surface. The patch  1000  preferably has a hole  1002  that is aligned with hole  402  of pocket. One suitable adhesive is Fast Dry Self-vulcanizing Cement made by the Rubber Patch Company. The filter housing is then inserted onto the rubber patch  1000 , ensuring the holes  1002 ,  402  and  312  are aligned. Preferably, the filter housing bottom  900  has a rubber coating  902  which is first buffed, and then affixed to the rubber patch  1000 . 
         [0038]    Alternatively, the pocket bottom surface  902  and filter housing bottom  402  may be coated with a suitable adhesive, eliminating the need to coat both sides of the patch with a suitable adhesive. 
         [0039]    The filter housing bottom, patch and pocket and adhesive may then be heat cured or cured at room temperature. 
         [0040]    The following steps are followed to mount the regulator device  200 . First, the regulator mounting surface  203  and sides of the regulator are buffed with abrasive material such as sandpaper. Next the mounting surface  203  and sides of the regulator are pretreated with Chemlock or other suitable adhesive, ensuring the holes  708 , 202 , 710  are protected from the application of adhesive. Preferably, the regulator housing is placed in a mold and rubber is injection molded to enrobe the regulator mounting surface and sides with rubber or elastomer such as cushion gum, however any type of rubber would work. The coating of rubber may be cured or partially cured about the regulator housing. 
         [0041]    Next, inner liner surface of the tire is buffed. Depending upon the weight of the regulator, the inner tire surface may need to be buffed down to the ply. As shown in  FIG. 6 , a green rubber patch  1100  is used to secure the regulator to the tire pocket bottom surface. The green rubber patch  1100  is buffed on both sides. The rubber patch  1100  is then coated with a suitable adhesive on both sides and then inserted onto the inner surface of the tire. The patch  1100  preferably has holes  1102 , 1104 , 1106  that are aligned with holes  704 , 406 , 706  of tire. One suitable adhesive is Fast Dry Self-vulcanizing Cement made by the Rubber Patch Company. The Next, the regulator mounting surface is mounted over the rubber patch  1000 , ensuring the holes  1102 , 1104 , 1106  are aligned with the regulator holes  708 , 202 ,  710  and with tire holes  704 , 406 , 706 . The regulator is then cured to the tire with heat or room temperature cure, depending upon the adhesive selected. 
         [0042]    Adjacent the pocket are two holes  704 , 706  as shown in  FIG. 5 . The holes  704 , 706  extend through the sidewall of the tire and are in fluid communication with aligned holes  708 ,  710  of the regulator. Pump tubes  702 ,  704  have a first end  703 , 705  that are inserted through holes  704 , 706  and into regulator holes  708 , 710 . Pump tubes  702 , 704  preferably have quick connects on both ends such as barbs, etc. so that the system may be easily assembled. Pump tubes  702 , 704  are preferably made of high strength polyurethane. Pump tubes have a second end  712 , 714  that are bent about 90 degrees. The second ends  712 , 714  are connected to the pump ends  42   a , 42  and then inserted into slots  716 , 718  formed adjacent the pocket. 
         [0043]    After the pump passageway is connected to the second ends  712 , 714  of the pump tubes, the pump passageway is inserted into channel  44 . Preferably, the pump passageway is coated with rubber cement and then inserted into the pump passageway. A green cover strip of rubber having an inner surface is first coated with rubber cement and then is placed over the pump passageway in the annular channel. Heat may be used to cure the rubber cement. 
         [0044]    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.