Abstract:
A tire includes a pair of sidewalls in spaced apart relation and extending substantially radially from a respective inner circumferential portion to a respective outer circumferential portion, a tread extending between and connecting outer circumferential portions of the sidewalls, at least a portion of a tire cavity defined by the tread and sidewalls, and a bead portion on the inner circumferential portion of each radially extending sidewall, the bead portion providing an engagement surface for engaging a wheel on which the tire is to be mounted, and a noise reducing foam disposed in at least a portion of the tire cavity.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to tires for vehicles, and more particularly, to tires that generate less noise than prior art tires, as well as tires that can be used without being filled with pressurized gas. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0002]    An embodiment of the invention includes a tire having a pair of sidewalls in spaced apart relation and extending substantially radially from a respective inner circumferential portion to a respective outer circumferential portion, a tread extending between and connecting outer circumferential portions of the sidewalls, at least a portion of a tire cavity defined by the tread and sidewalls, and a bead portion on the inner circumferential portion of each radially extending sidewall, the bead portion providing an engagement surface for engaging a wheel on which the tire is to be mounted. A noise reducing foam is disposed in at least a portion of the tire cavity. 
         [0003]    Another embodiment of the invention includes a vehicle tire system having a system controller configured to receive at least one sensor output signal indicative of a value of at least one respective monitored characteristic of at least one tire. Each of the at least one tire includes a pair of substantially radially extending sidewalls, a tread extending between and connecting outer circumferential portions of the sidewalls, at least a portion of a tire cavity defined by the tread and sidewalls, and a bead portion on an inner circumferential portion of each radially extending sidewall, the bead portion providing an engagement surface for engaging a wheel on which the tire is to be mounted. The system controller includes a computer processor connected to a computer readable storage medium containing computer executable code that, when executed by the computer processor, causes the system controller to, responsive to the respective monitored characteristic of at least one tire departing from a predefined range of values, initiate an alarm. 
         [0004]    These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0005]    The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0006]      FIG. 1  is a schematic cross sectional illustration, taken through a diametral plane of tread of a low noise tire according to embodiments disclosed herein; 
           [0007]      FIG. 2  is a schematic cross sectional illustration, taken through a circumferential plane of the tread, of a low noise tire according to embodiments disclosed herein; 
           [0008]      FIG. 3  is a schematic cross sectional illustration, taken through a diametral plane of the tread, of a low noise tire according to embodiments disclosed herein; 
           [0009]      FIG. 4  is a schematic cross sectional illustration, taken through a circumferential plane of the tread, of a low noise tire according to embodiments disclosed herein; 
           [0010]      FIG. 5  is a schematic cross sectional illustration, taken through a diametral plane of the tread, of a low noise tire according to embodiments disclosed herein; 
           [0011]      FIG. 6  is a schematic cross sectional illustration, taken through a circumferential plane of the tread, of a low noise tire according to embodiments disclosed herein; 
           [0012]      FIG. 7  is a schematic cross sectional illustration, taken through a diametral plane of the tread, of a low noise tire according to embodiments disclosed herein; 
           [0013]      FIG. 8  is a schematic cross sectional illustration, taken through a circumferential plane of the tread, of a low noise tire according to embodiments disclosed herein; 
           [0014]      FIG. 9  is a schematic illustration of a vehicle tire system including a low noise tire according to embodiments disclosed herein; and 
       
    
    
       [0015]    The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIGS. 1 and 2  show an example of a low noise tire  100  according to an embodiment disclosed herein. Two sidewalls  110  extend substantially radially from respective inner circumferential portions to respective outer circumferential portions in spaced apart relationship as particularly seen in  FIG. 1 . A tread  120  connects the sidewalls  110 , and together the tread  120  and sidewalls define a tire cavity  130 . In pneumatic tires, the tire cavity  130  is filled with pressurized gas, such as air. In the embodiment seen in  FIGS. 1 and 2 , the tire cavity  130  is substantially filled with a noise reducing foam  140 , forming a substantially toroidal body  142  of noise reducing foam  140 . Particles  141  are dispersed in the noise reducing foam  140  in embodiments to further reduce noise as will be explained below, though the particles  141  are not required to achieve noise reduction. As a result of the structure seen in  FIGS. 1 and 2 , the tire  100  is essentially non-pneumatic, though embodiments include toroidal bodies  142  permeated with pressurized gas. The embodiment of the tire  100  shown in  FIGS. 1 and 2  therefore can run with no air, providing a run flat feature. 
         [0017]    The noise reducing foam  140  in embodiments is selected for reduction of a desired range or ranges of frequencies of sound to be reduced. Additionally, the noise reducing foam  140  can be selected at least in part for its performance in run flat or non-pneumatic conditions. Open cell foams are used in embodiments, while other embodiments use closed cell foams and/or combinations of open and closed cell foams depending upon the particular noise reduction characteristics and/or performance characteristics desired. 
         [0018]    To enhance noise reduction and/or performance, one or more characteristics of the noise reducing foam  140  is varied in the toroidal body  142  in embodiments. For example, a ratio of open cell to closed cell foam content can be varied with radial location, longitudinal location, or both. Other examples of characteristics of the toroidal body  142  that are varied in embodiments include, but are not limited to, density, tensile strength, compressive strength, hardness, and rigidity or stiffness. 
         [0019]    To further enhance noise reduction, particles  141  dispersed in at least part of the foam  140  in embodiments are in a particular range of sizes and particular materials to absorb, reflect, dampen, or otherwise reduce desired frequencies of sound. Multiple ranges of sizes and/or multiple materials are used to handle multiple frequencies or frequency ranges of sound to be reduced. For example, particles of polytetrafluoroethane of from about 5 microns to about 10 microns will absorb sounds in a range of from about 5000 Hertz (Hz) to about 6000 Hz, while particles of steel wire of from about 0.5 millimeters to about 1.5 millimeters will absorb sound in a range of from about 500 Hz to about 600 Hz. 
         [0020]      FIGS. 3 and 4  show another example of a tire  100  according to an embodiment of the invention. As in the example of  FIGS. 1 and 2 , the example of  FIGS. 3 and 4  has two sidewalls  110  connected by a tread  120  to define a tire cavity  130 , and bead portions  111  that facilitate mounting of the tire  100  on a wheel. Noise reducing foam  140  is still present and can advantageously have particles  141  dispersed therein. However, in an embodiment the noise reducing foam  140  extends part way into the tire cavity  130  instead of filling it. In an embodiment, the toroidal body  142  formed by the noise reducing foam  140  includes a coating or film  143  on its outer surface in the tire cavity  130  to enhance noise reduction. The coating or film  143  in an embodiment is sound reflective, though in other embodiments the sound reflective coating instead of or in addition to being sound reflective is sound absorbing. Suitable materials for the film include but are not limited to aluminized mylar (PET), a metal mesh in a mylar or other polymer film, or any other material having sound reflective or sound absorbing characteristics suitable for the purposes disclosed herein. 
         [0021]      FIGS. 5 and 6  show an example of a tire  100  that is based on the example shown in  FIGS. 3 and 4 . As seen in  FIGS. 5 and 6 , substantially radially extending buttresses  150  are disposed within the tire cavity  130 . The buttresses  150  add strength to the tire and can advantageously divide the tire cavity  130  into separate compartments. In embodiments in which the tire cavity  130  contains pressurized gas, the buttresses  130  can form seals with the toroidal body  142  so that the compartments are substantially air tight. Such air tight compartments greatly reduce circulation of gas within the tire cavity  130 , which can further reduce noise and can enhance tire performance. Embodiments can further include valves  151  that selectively allow fluid communication between compartments. 
         [0022]    The particular dimensions of the buttresses  150  will vary depending on the strength required and whether the buttresses  150  are to form air tight compartments. An embodiment has the buttresses  150  extending across the entire cross section of the tire cavity  130  as seen in the example of  FIGS. 7 and 8 . In embodiments employing buttresses  150 , the noise reducing foam  140  can extend partly into the tire cavity  130  as shown in  FIGS. 3-6  and can also fill the tire cavity  130  as shown in  FIGS. 1 and 2 . A manufacturing method includes forming the tire cavity  130  with the sidewalls  110  and tread  120 , forming the buttresses  150 , and applying the noise reducing foam  140  so that the noise reducing foam  140  fills the circumferential volume, at least to the radial extent of the toroidal body  143  into the tire cavity  130 , between and around the buttresses. 
         [0023]    Embodiments of the low noise tire  100  are used in a vehicle tire system  200 , an example of which is seen schematically in  FIG. 9 . A system controller  220  is in signal communication with a sensor  210  arranged to monitor a characteristic of a tire  100  according to an embodiment. The characteristic can include tire pressure, tire strain, tire temperature, and/or other characteristics of the tire  100 , and more than one sensor  210  can be employed to obtain multiple measurements of a characteristic and/or to monitor multiple tire characteristics. 
         [0024]    The system controller  220  includes a computer processor  221  that receives the signal from the sensor  210  and that is in communication with a computer readable storage medium  222  containing computer executable instructions  223 , such as executable computer code. Additionally, the computer processor  221  is in communication with an alarm initiating circuit  224 , though in an embodiment the computer processor  221  includes the alarm initiating circuit  224  and/or performs the function of the alarm initiating circuit  224  as a result of executing computer executable instructions  223 . 
         [0025]    The computer processor  221  and/or the alarm initiating circuit  224  are in communication with one or more devices, including, but not limited to, an indicator  230 , such as a light on a dashboard, a display  240 , such as a computer display, a sound generating system  250 , such as a speaker, and a communications system  260 , such as a cellular or satellite telephone, or any other wireless communication system suitable for the purposes disclosed herein. In embodiments, the computer executable instructions  223 , when read and executed by the computer processor  221 , cause the computer processor  221  to, responsive to the characteristic monitored by the sensor  210  departing from a predefined range of values, initiate an alarm with the alarm initiating circuit  224 . For example, in embodiments in which the tire  100  contains pressurized gas, the sensor  210  can be a tire pressure sensor, such as a sensor mounted in fluid communication with the tire cavity  130 . When the tire pressure becomes too high, such as above about 45 pounds per square inch, or too low, such as below about 25 pounds per square inch, the computer processor  221  causes an alarm to be initiated. The range of values provided above is an example for illustrative purposes, and other ranges of values are used in embodiments as appropriate for a particular tire implementation and/or vehicle installation. 
         [0026]    In embodiments, the alarm comprises illuminating an indicator  230 , such as an indicator light on a dashboard or an indicator on the display  240  of the vehicle, such as a LCD (liquid crystal display), LED (light emitting diode), OLED (organic light emitting diode), CRT (cathode ray tube), or other type of display as may be used with computer systems and user interfaces. The alarm can also include producing an audible alarm in the interior of the vehicle, such as via the sound generating system  250 . The alarm can also include providing information regarding a closest service center via the display  240  or the sound generating system  250 . In embodiments, the system  200  can further act, as part of the alarm, to limit the speed of operation or distance to travel of the vehicle so as to prolong effective performance of the tire  100  and can display or announce information regarding distance traveled since the monitored characteristic departed from the predefined range of values, distance remaining before performance of the tire  100  substantially degrades, or other information as may be applicable in a given installation. The alarm can further include use of the communications device  260  to call for assistance, such as via a remotely located assistive service  300 . An example of such an assistive service is the OnStar hands-free communication service offered by General Motors Corporation, which owns the rights to the mark, ONSTAR. 
         [0027]    A method according to embodiments is realized via, and a system according to embodiments includes, computer-implemented processes and apparatus for practicing such processes, such as the system controller  220  and/or computer processor  221 . Additionally, an embodiment includes a computer program product including computer code  223 , such as object code, source code, or executable code, on tangible media, such as magnetic media (floppy diskettes, hard disc drives, tape, etc.), optical media (compact discs, digital versatile/video discs, magneto-optical discs, etc.), random access memory (RAM), read only memory (ROM), flash ROM, erasable programmable read only memory (EPROM), or any other computer readable storage medium  222  on which the computer program code  223  is stored and with which the computer program code  223  can be loaded into and executed by a computer. When the computer executes the computer program code, it becomes an apparatus for practicing the invention, and on a general purpose microprocessor, specific logic circuits are created by configuration of the microprocessor with computer code segments. A technical effect of the executable instructions is to implement tire monitoring so that, in the event of an abnormal condition of one or more vehicle tires  100 , an alarm is initiated to warn the vehicle operator, provide assistance and information regarding the abnormal condition, and/or provide assistance and information regarding obtaining help in repairing or replacing the one or more tires  100 . An additional technical effect of the executable instructions that may be included is to limit vehicle operation, such as by providing a control signal for limiting speed or distance of travel of the vehicle, to prevent substantial degradation of the one or more tires  100 . 
         [0028]    The computer program code is written in computer instructions executable by the controller, such as in the form of software encoded in any programming language. Examples of suitable programming languages include, but are not limited to, assembly language, VHDL (Verilog Hardware Description Language), Very High Speed IC Hardware Description Language (VHSIC HDL), FORTRAN (Formula Translation), C, C++, C#, Java, ALGOL (Algorithmic Language), BASIC (Beginner All-Purpose Symbolic Instruction Code), APL (A Programming Language), ActiveX, HTML (HyperText Markup Language), XML (eXtensible Markup Language), and any combination or derivative of one or more of these. 
         [0029]    The flow diagrams depicted herein are just one example. There may be many variations to this diagram or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention. 
         [0030]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.