Patent Publication Number: US-8991456-B2

Title: Reversible air maintenance tire and pump assembly

Description:
FIELD OF THE INVENTION 
     The invention relates generally to air maintenance tires and, more specifically, to a tire and integrated pump assembly. 
     BACKGROUND OF THE INVENTION 
     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 dependant 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. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the invention, an air maintenance tire and pump assembly is provided, the pump assembly including an elongate annular air passageway enclosed within a bending region of a tire, the air 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. The pump assembly further includes an air inlet port assembly coupled to channel outside air into the air passageway at an inlet junction; a pair of inline valves positioned to direct a flow of the inlet air in opposite directions into the air passageway; and a pair of outlet valves, each positioned at a downstream side of a respective inline valve, the outlet valves directing a bi-directional flow of the inlet air from the downstream side of a respective inline valve toward the tire cavity. 
     In another aspect, the inlet port assembly includes a control conduit extending between and conducting an inlet air flow between the air inlet portal and an upstream side of the inline valves, and a valve actuator for interrupting the inlet air flow through the control conduit to the inline valves when the air pressure within the tire cavity is above the threshold air pressure level. 
     The invention in a further aspect is configured having a valve actuator piston seated within a valve housing cavity, the control conduit transversely extending across the piston and reciprocally moving with the piston between the closed, misaligned orientation with the upstream sides of the inline valves and an open, aligned orientation with the upstream sides of the inline valves. 
     A further aspect is that the inline and the outlet valves are selectively opened by bi-directional air flow within the air passageway and wherein the direction of bi-directional air flow is dictated the forward and reverse directions in which the tire rotates. 
     Definitions 
     “Aspect ratio” of the tire means the ratio of its section height (SH) to its section width (SW) multiplied by 100 percent for expression as a percentage. 
     “Asymmetric tread” means a tread that has a tread pattern not symmetrical about the center plane or equatorial plane EP of the tire. 
     “Axial” and “axially” means lines or directions that are parallel to the axis of rotation of the tire. 
     “Ball check valve” is a check valve in which the closing member, the movable part to block the air flow, is a spherical ball. In some ball check valves, the ball is spring-loaded to help keep it shut and require a specified magnitude of upstream pressure on the ball to overcome the bias of the valve spring for the valve to open. The interior surface of the main seats of ball check valves may be conically-tapered to guide the ball into the seat and form a positive seal when stopping reverse flow. 
     “Chafer” is a narrow strip of material placed around the outside of a tire bead to protect the cord plies from wearing and cutting against the rim and distribute the flexing above the rim. 
     “Check valve” is a two-port valve having two openings in the body, one for air to enter and the other for air to leave. 
     “Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction. 
     “Cracking pressure” is the minimum upstream pressure at which the valve will operate. Typically, a check valve is designed for and can therefore be specified for a specific cracking pressure. 
     “Downstream” is a direction away from the source of power, i.e. the direction away from the source of air flow. In the context of a valve, “downstream” refers to a side of the valve from which air flows out of the valve when an “upstream” air flow on the valve exerts cracking pressure sufficient to open the valve. 
     “Equatorial Centerplane (CP)” means the plane perpendicular to the tire&#39;s axis of rotation and passing through the center of the tread. 
     “Footprint” means the contact patch or area of contact of the tire tread with a flat surface at zero speed and under normal load and pressure. 
     “Groove” means an elongated void area in a sidewall that may extend circumferentially or laterally about the tread in a straight, curved, or zigzag manner. Circumferentially and laterally extending grooves sometimes have common portions. The “groove width” is equal to the surface area occupied by a groove or groove portion, the width of which is in question, divided by the length of such groove or groove portion; thus, the groove width is its average width over its length. Grooves may be of varying depths in a tire. The depth of a groove may vary around the circumference of the tread, or the depth of one groove may be constant but vary from the depth of another groove in the tire. If such narrow or wide grooves are substantially reduced depth as compared to wide circumferential grooves which the interconnect, they are regarded as forming “tie bars” tending to maintain a rib-like character in tread region involved. 
     “Inboard side” means the side of the tire nearest the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
     “Lateral” means an axial direction. 
     “Lateral edges” means a line tangent to the axially outermost tread contact patch or footprint as measured under normal load and tire inflation, the lines being parallel to the equatorial centerplane. 
     “Net contact area” means the total area of ground contacting tread elements between the lateral edges around the entire circumference of the tread divided by the gross area of the entire tread between the lateral edges. 
     “Non-directional tread” means a tread that has no preferred direction of forward travel and is not required to be positioned on a vehicle in a specific wheel position or positions to ensure that the tread pattern is aligned with the preferred direction of travel. Conversely, a directional tread pattern has a preferred direction of travel requiring specific wheel positioning. 
     “Outboard side” means the side of the tire farthest away from the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
     “Peristaltic” means operating by means of wave-like contractions that propel contained matter, such as air, along tubular pathways. 
     “Radial” and “radially” means directions radially toward or away from the axis of rotation of the tire. 
     “Rib” means a circumferentially extending strip of rubber on the tread which is defined by at least one circumferential groove and either a second such groove or a lateral edge, the strip being laterally undivided by full-depth grooves. 
     “Sipe” means small slots molded into the tread elements of the tire that subdivide the tread surface and improve traction, sipes are generally narrow in width and close in the tires footprint as opposed to grooves that remain open in the tire&#39;s footprint. 
     “Tread element” or “traction element” means a rib or a block element defined by having a shape adjacent grooves. 
     “Tread Arc Width” means the arc length of the tread as measured between the lateral edges of the tread. 
     “Upstream” is a direction toward the source of air flow power, i.e. the direction from which air flows or is coming from. In the context of a valve, “upstream” refers to a side of the valve into which air flows when an “upstream” air flow on the valve exerts cracking pressure sufficient to open the valve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described by way of example and with reference to the accompanying drawings in which: 
         FIG. 1  is an isometric view of tire, rim and tubing with peristaltic pump and inlet valve. 
         FIG. 2A  is a side view of the tire and peristaltic pump assembly with the tire rotating counterclockwise and establishing a footprint against a ground surface. 
         FIG. 2B  is a side view of the tire and peristaltic pump assembly with the tire rotating clockwise against a ground surface. 
         FIG. 3A  is a cross sectional schematic diagram of the inlet portal of the peristaltic pump having a two-port inlet control valve in the closed position. 
         FIG. 3B  is a cross sectional schematic diagram of the inlet portal of the peristaltic pump having a two-port inlet control valve in the open position operable to fill the tire with the tire rotating in a counter clockwise direction. 
         FIG. 3C  is a cross-sectional schematic diagram of the inlet portal of the peristaltic pump bi-directional valve having two-port inlet control which fills the tire with the tire rotating in a clockwise direction. 
         FIG. 4A  is a cross sectional schematic diagram of the inlet portal of the peristaltic pump having an alternatively configured bi-directional five-port inlet control valve in the closed position. 
         FIG. 4B  is a cross sectional schematic diagram of the inlet portal of the peristaltic pump having an alternatively configured bi-directional five-port inlet control valve shown in the open position operable to fill the tire with the tire rotating in a counter clockwise direction. 
         FIG. 4C  is a cross-sectional schematic diagram of the inlet portal of the peristaltic pump bi-directional valve having an alternatively configured five-port inlet control which fills the tire with tire rotating in a clockwise tire rotation. 
         FIG. 5A  is a cross-sectional schematic diagram of the inlet portal of an alternative peristaltic pump bi-directional valve filling a tire with the tire in a counter-clockwise rotation in which the valve has incorporated therein a five port regulator. 
         FIG. 5B  is a cross-sectional schematic diagram of the inlet portal of the  FIG. 5A  alternative peristaltic pump bi-directional valve filling a tire with the tire in a clockwise rotation and showing the five port regulator. 
         FIG. 5C  is a cross-sectional schematic diagram of the inlet portal of the  FIG. 5B  alternative peristaltic pump bi-directional valve with clockwise tire rotation and the valve in a bypass mode. 
         FIG. 5D  is a cross-sectional schematic diagram of the inlet portal of the  FIG. 5B  alternative peristaltic pump bi-directional valve with counter-clockwise tire rotation and the valve in a bypass mode. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 ,  2 A and  2 B, a tire and pump assembly includes a tire of conventional construction having a pair of sidewalls  12  extending to a tread  14  and enclosing a tire air cavity  26  defined by a tire inner liner layer  25 . A peristaltic pump assembly  16  inlet, including a T-inlet intersection, is attached to one or both of the tire sidewalls  12  in generally a high bend region of the sidewall. The peristaltic pump assembly  16  includes an annular air passageway  20  either in the form of an independent tube formed separately from the tie and assembled to the tire in a post-manufacture procedure; or an air passageway formed as an integral void within the sidewall during tire manufacture. The air passageway  20  is enclosed by the sidewall and extends along an annular path about a region of the sidewall that experiences a high flex or bend as the tire rotates. If in an independent tube form, the air passageway tube is formed of a resilient, flexible material such as plastic or rubber compounds that are capable of withstanding repeated deformation cycles wherein the tube is deformed into a flattened condition subject to external force and, upon removal of such force, returns to an original condition generally circular in cross-section. If the air passageway is integrally formed within the sidewall, the air passageway likewise must withstand repeated deformation and recovery cycles as the tire rotates and be of a diameter sufficient to operatively pass a volume of air sufficient for the purposes described herein. The general operation of an air tube in a peristaltic pump is described in U.S. Pat. No. 8,113,254 which is incorporated herein by reference. 
     Opposite ends  22 ,  24  of the air passageway terminate at an inlet port assembly  28 . The inlet port assembly is affixed to rotate with the tire as the tire rotates against a ground surface  132 . Rotation of the tire creates a footprint  134  against surface  132  which in turn introduces compression force  138  into the tire. The compression force  138  in turn is applied at  140  into the air passageway  20  causing segment by segment collapse of the passageway as the tire rotates. The segment by segment collapse of the air passageway occurs regardless of whether the tire rotates in the counterclockwise direction  136  of  FIG. 2A  or the clockwise direction  133  of  FIG. 2B . The peristaltic pump assembly is thus said to be bi-directional or reversible in operating to pump air into the tire cavity  26  in both a forward or a reverse direction of air flow continuously throughout a 360 degree tire rotation. 
     As the tire rotates in both forward and rearward directions  136 ,  133  of  FIG. 2A  or  2 B, the air passageway  20  is flattened segment by segment whether the passageway is in the form of a separate sidewall embedded tube or an integrally formed void. The segment by segment  137  sequential flattening of the air passageway moves in a direction  142  opposite to the direction of tire rotations of  FIGS. 2A and 2B . The sequential flattening of the passageway  20  segment by segment causes evacuated air from the flattened segments to be pumped in the direction  142  to the inlet port assembly  28  where the air is directed to the tire cavity. Air pressure within the cavity  26  is thus maintained at a desired threshold pressure. Air admitted by the inlet port assembly  28  is introduced into the air passageway  20  to replenish air pumped into the tire cavity or recirculated out of the pump assembly if not needed to maintain tire pressure at a desired level. 
     The inlet port assembly  28  includes a regulator valve assembly  30  and a filtered air entry port  32 . A two port, bi-directional inlet control embodiment is shown in  FIGS. 3A through 3C .  FIG. 3A  representing the Inlet Control in the closed position;  FIG. 3B  shows the Inlet Control open with air flow moving counter-clockwise and the tire rotating clockwise; and  FIG. 3C  shows the Inlet Control open with air flow moving clockwise and the tire rotating counter-clockwise. It will be appreciated that the system is bi-directional, with air flow within the passageway  20  occurring in both directions as the tire rotates, with the direction of air flow within the passageway  20  dictated by the tire rotating in either a forward or reverse direction. Pumping along passageway  20  occurs in both directions, alternatively, throughout an entire 360 degree rotation of the tire. 
     A filtered air entry port  32  is positioned at the outer surface of a tire sidewall  12  and outside air is admitted into the entry port through a cellular filter  34  housed within a cylindrical housing  36 .  FIG. 3A  shows the assembly in the closed condition in which air from outside the tire is prevented from entering the entry port  32 ; a condition which will occur when the pressure within the tire cavity  26  is at or above a regulated pressure threshold Preg. An air passageway conduit  56  extends from the filter housing  36  to the regulator valve assembly  30  and passes inlet air to the valve assembly. From the regulator valve assembly  30  an outlet conduit  54  carries air flow to a connecting conduit  40  which conducts air flow into oppositely directed valves  62 ,  64  positioned adjacent and on opposite sides of the inlet junction  38 . As used herein, “inlet junction” refers to the location of passageway branching of inlet air from the assembly  28  to the upstream sides of inline stop valves. Alternative configurations of the system are shown by  FIGS. 3A through 3C ,  4 A through  4 C, and  5 A through  5 D wherein the inlet junction for each are placed as will be explained for the differing valve configurations. 
     The regulator valve assembly  30  provides a valve housing  42  and valve piston  22  residing within a cylinder or housing chamber  46 . A biasing mechanism such as a spring  48  exerts a biasing force (see arrow  72  in  FIGS. 3B ,  3 C) on the piston  44 , biasing the piston downward within cylinder  46  into an “open” or “tire-fill” location and position as indicated in  FIG. 3B  and  FIG. 3C . When the pressure within the cavity  26  is at or greater than the Preg pressure setting level, the pressure will overcome the biasing force of spring  48  and force (see arrow  50 ) the piston upward within cylinder  46  into the “closed” or “no-fill” location and position of  FIG. 3A . The piston  22  is provided with a transversely extending air conduit  52  extending across the piston body. In the “closed” position of  FIG. 3A , the conduit  52  is misaligned with respect to the air conduits  54 ,  56  and air cannot flow across the piston to conduits  54 ,  56 , and from there to the inlet junction  38 . In the “closed” position, consequently, air flow is prevented from reaching the inlet control junction  38  and hence, prevented from reaching the upstream sides of valves  62 ,  64 . Air flow into the passageway  20  is thus precluded with the valve assembly  30  in the closed position of  FIG. 3A . 
       FIG. 3B  shows the valve assembly  30  moving to an “open” position. The “open” position The tire rotates in a clockwise direction, causing air to be pumped along passageway  20  in a counter clockwise direction. A configuration of four one-way valves are provided and located as shown. Two inline valves  62 ,  64  are positioned along the conduit  40  on opposite side of the inlet junction  38 . The two inline valves  62 ,  64  open in opposite directions along the conduit  40  and conduct air flow in such respective directions with the valves  62 ,  64  in an open condition. Conduit  40  connects at the downstream side of the valves  62 ,  64  with the air passageway  20 . From the juncture of passageway  40  and the passageway  20 , radially extending outlet conduit passageways  58 ,  60  extend to the tire cavity  26  as shown. Positioned along the conduits  58 ,  60  are two outlet one-way valves  66 ,  68 , respectively. The valves  66 ,  68  are oriented to open in a direction toward the tire cavity to permit the flow of air through the valves  66 ,  68 , along conduits  58 ,  60 , and into the tire cavity  26 . 
     The one-way valves  62 ,  64 ,  66 , and  68  are of a type commercially available such as ball or diaphragm check valves or other known valve configurations. The valves are oriented to open in the direction shown when pressure at an upstream side of the valve overcomes a biasing spring and forces the ball away from its seat. The piston  44  moves downward under the biasing force exerted by actuator spring  48 . When the air pressure, Preg, within the cavity  26  falls below a desired pressure threshold limit. Movement of the piston aligns the air conduit  52  across the piston  44  with the conduits  54 ,  56 , allowing inlet air from the inlet filter port  32  to flow across the piston conduit  52  to the inlet control junction  38  and to the connecting conduit  40 . The tire, in rotating clockwise against the ground surface  132  (See  FIG. 2B ), collapses the passageway  20  segment by segment opposite the created tire footprint  134 . The collapsed segments create a vacuum which, in turn, are refilled segment by segment by a flow of air within the passageway in a counterclockwise direction  142 , drawn in through the inlet port assembly  28 . The counterclockwise flow of input air forces the one-way valve  64  open, allowing the air to flow into the passageway in the counterclockwise direction shown. The air circulates around the passageway  20 . When the air flow reaches the juncture of conduit  40  and radial outlet conduit  60 , it cannot flow through the closed valve  62  and must, instead, flow to the outlet valve  68 . The air flow forces the valve  68  open and continues on to input air into the tire cavity  26  as indicated by the arrow  70 . When air pressure within the tire cavity  26  reaches the desired preset level, tire pressure against piston  44  forces the piston into the closed position of  FIG. 3A  and air flow to the cavity is discontinued as explained previously. 
     The above operation of the peristaltic pump assembly  16  operates the same in the reverse tire rotation direction, as will be understood from  FIG. 3C . In  FIGS. 2A and 3C , with the tire rotating in the counterclockwise direction, air is pumped in the clockwise direction  142 .  FIG. 3  shows the inlet port assembly  28  and the regulator valve assembly  30  in such a condition. If pressure within the cavity  26  is below the preset Preg level, the piston  44  is biased by spring  48  into the open position shown. The piston conduit  52  aligns with the conduits  54 ,  56  and air flow is directed to the junction  40 . Rotation of the tire in the counterclockwise direction causes the flow of air to be in the clockwise direction  74  as evacuated segments of the passageway  20  are refilled. Air flow in the clockwise direction opens the one way valve  62  and allows air to circulate from the conduit  40  into passageway  20 . The pressurized air circulates passageway  20  and enters conduit  58  where it is directed against valve  66 , opening the valve, and thereby passing through valve  66  to the tire cavity  26  as indicated by arrow  70  of  FIG. 3C . As with the  FIG. 3 , when the air flow reaches the juncture of conduit  40  and radial outlet conduit  58 , it cannot flow through the closed valve  64  and must, instead, flow to the outlet valve  66 . The air flow that forces the valve  66  open continues to input air into the tire cavity  26  as indicated by the arrow  70 . When air pressure within the tire cavity  26  reaches the desired preset level, tire pressure against piston  44  forces the piston into the closed position of  FIG. 3A  and air flow to the cavity is discontinued as explained previously. 
       FIGS. 4A through 4C  show an alternative embodiment in which the regulator valve assembly  78  is a 5-port inlet control configuration. It will be appreciated that alternative valve configurations may be employed in the practice of the invention and that the system is not dependent upon the use of a particular valve. In  FIG. 4A , the valve is in the closed position in which air is not input into the tire cavity  26 .  FIG. 4B  shows the valve in the open position with a tire clockwise rotational direction and air flow in the counter clockwise direction.  FIG. 4C  shows the valve in the open position during a counterclockwise tire rotation and clockwise air flow direction. As will be appreciated, in the valve shown in  FIGS. 4A through 4C , air is admitted into the system through inlet port assembly  76  to the regulator valve assembly  78 . Port assembly  76  includes a filter inlet port  80  and a filter body  82  housed within filter housing  84 . Air passing through the filter  82  is directed via inlet conduit  86  to a transverse piston conduit  88 . The junction  90  created by intersection of the inlet conduit  86  and piston conduit  88 , in the alternative embodiment, is located within the piston  92 . The piston  92 , as in the first embodiment, is biased by spring  94  in an open condition represented by  FIGS. 4B and 4C  should the air pressure within cavity  26  be less than a preset Preg level. If air pressure within the cavity  26  is at or above the Preg level, the cavity air pressure overcomes the biasing spring  94  and moves the piston  92  upward within cylinder  98  into the closed position of  FIG. 4A . In the closed position, no air is pumped into the cavity. 
     The transverse conduit  88  of the piston aligns with bridging conduits  100 ,  102  in the open-valve conditions of  FIG. 4B and 4C  and misalign with bridging conduits  100 ,  102  when the valve is closed as shown in  FIG. 4A . Four one-way valves  106 ,  108 ,  110 , and  112  are positioned, the valves  108  and  110  representing the inline valves and the valves  112  and  106  the outlet valves. The inline valves  108 ,  110  open in opposite directions away from the junction  90  and the outlet valves  112 ,  106  open radially inward toward the tire cavity  26 . The outlet valves  112 ,  106  reside within outlet conduits  103 ,  101 , respectively, which couple to the passageway  20 . The conduits  103 ,  101  intersect and connect with the bridging conduits  102 ,  100  respectively, and continue radially inward beyond the outlet valves  112 ,  106  to exit ends  22 ,  24  at the tire cavity  26 . 
     Operation of the five port valve configuration of  FIGS. 4A through 4C  operates analogously to that explained previously in regard to the two-port valve of  FIGS. 3A through 3C .  FIGS. 2B ,  4 B shows the regulator valve open with the tire rotating clockwise and causing a counterclockwise flow of air within passageway  20 . Air admitted through the input valve assembly  76  is directed to the junction  90  in piston  92  by means of conduit  86 . At the junction  90 , the air flow is prohibited from passing through the closed valve  108  and opens the valve  110 . The air flow circulates in direction  114  within the passageway  20  to enter into the conduit  101 . Air flow at the junction of conduit  101  and the bridging conduit  100  cannot pass through the closed valve  108  and thus is directed to open valve  106 , allowing the pumped air flow to enter into the tire cavity  26 . 
       FIGS. 2A and 4C  show operation of the regulator valve with the tire rotating in a counterclockwise direction  136  to pump airflow within passageway  20  in a clockwise fill direction  118 . Air flow  118  in the passageway  20  is directed to the tire cavity  26  as indicated. Operation of the valve in the tire rotation direction and counter air flow direction in  FIGS. 2A and 4C  proceeds as explained above. When air pressure within the tire cavity  26  reaches the desired preset level, tire pressure against piston  92  forces the piston into the closed (conduit-misaligned) position of  FIG. 3A  and air flow to the cavity is discontinued. A pressure within the cavity  26  below the preset desired threshold level, causes the piston  92  to move into the open position of  FIG. 4B  or  4 C, and air to flow in the passageway  20  in the direction indicated as dictated by the direction of tire rotation. Pumping of air continues throughout the 360 degree rotation of the tire and, as shown, occurs regardless of whether the tire (and vehicle) is going in the forward or reverse directions. 
       FIGS. 5A through 5D  show the a third alternative embodiment of the regulator valve assembly  78  modified by the inclusion of a bypass valve  120 . The valve  120  is a pressure controlled valve of a type commercially available that is connected to bypass the opening of check valves  106 ,  112  when the pressure within the tire cavity  26  exceeds a Pset or Preg value. The bypass valve  120  is intended to ensure that air cannot be introduced into the tire cavity  26  when the air pressure within the cavity is at or greater than the Pset pressure threshold. The bypass valve  120  is positioned to conduct air in either direction when the pressure within the cavity  26  is at or greater than the Pset value, whereby bypassing air to the outlet valves  106 ,  112  and preventing the introduction of more air into the cavity. Bypass valve  120  connects to conduit  120  spanning the piston  92  and connecting to the conduits  101 ,  103  at opposite ends.  FIG. 5A  shows the 5-port Bypass Regulator with the cavity pressure below Preg or Pset; the tire rotating in a clockwise direction, and fill air rotating about the passageway  20  in a counterclockwise direction. It will be noted that in the Bypass Regulator embodiment of  FIGS. 5A through 5D , the piston  92  does not move between an aligned, open, orientation to the conduits  100 ,  102  and a closed, misaligned, orientation but remains in alignment in all fill modes. 
     With reference to  FIG. 5A , the cavity pressure is below Pset, causing the Bypass valve  120  to be closed. With the Bypass valve  120  closed, the operation of the Regulator and air passageway  18  proceeds as explained above in reference to the second embodiment under the conditions of  FIG. 4B .  FIG. 5A  and  FIG. 4B  both represent a clockwise rotation of the tire, flow of air into (arrow  124 ) the system through filter inlet port  80 , and a counterclockwise flow of air (arrow  126 ) within passageway  20 . In  FIG. 5B , for a counterclockwise rotation of the tire and a clockwise fill direction, the Bypass valve  120  continues to remain closed so long as the cavity pressure remains below Preg. Air flow (arrow  128 ) along the bypass conduit is thereby blocked by the closed valve  126 . The air flow and fill direction in  FIG. 5B  thus proceeds as explained previously under the same analogous conditions under which the regulator of  FIG. 4  operates. Air circulating in  FIG. 5B  in the clockwise direction acts to open the outlet valve  112  and pass air in direction  130  into the tire cavity. In  FIG. 5C , with the cavity pressure at or greater than the Preg threshold, air circulated in the clockwise direction bypasses the outlet valves  106 ,  112 , passing instead through the opened bypass valve  120 . The valves  106 ,  112  thus remain closed and none of the circulated air (arrow  126 ) will pass through the valves  106 ,  112  and enter the tire cavity.  FIG. 5D  shows the operation of the Bypass Regulator during an opposite, clockwise rotation of the tire and a counter clockwise air flow path. As with  FIG. 5C , the tire cavity pressure in  FIG. 5D  is greater than Preg, causing the bypass valve  126  to open and directing the counterclockwise air flow (direction arrow  126 ) through the bypass valve path rather than opening and moving through the outlet valves  106 ,  112 . Air flow into the tire cavity is thus precluded. The Bypass Regulator thereby ensures that under no circumstances will air be forced into a tire cavity when the pressure within the cavity is at or regulator is at or greater than the Preg set threshold. 
     From the foregoing, it will be appreciated that the peristaltic pump and regulator system provides the means for keeping the air pressure within a tire cavity at a desired pressure level but no greater pressure that the desired pressure. The pump assembly  16  includes the elongate annular air passageway  20  enclosed within a bending region of the tire. The air passageway  20  operatively closes and opens, segment by segment, as the bending region of the tire passes through a rolling tire footprint to pump air along the air passageway. The pump assembly further includes the air inlet port assembly  28  positioned to channel outside air into the air passageway  20  at an inlet junction ( 38  or  90 ). The pair of inline valves  62 ,  64  (or  108 ,  110 ) are positioned to direct a flow of the inlet air in opposite directions into the air passageway  20 . The pair of outlet valves  66 ,  68  (or  106 ,  112 ), each are positioned at a downstream side of a respective inline valve, the outlet valves directing a bi-directional flow of the inlet air from the downstream side of a respective inline valve therethrough toward and into the tire cavity. 
     The inlet port assembly  28  further includes the control conduit extending between and conducting an inlet air flow between the air inlet portal and an upstream side of the inline valves. The piston  44  operates under the influence of valve spring actuator  48  to interrupt the inlet air flow through the control junction  38  and to the upstream side of the inline valves when the air pressure within the tire cavity is above the threshold air pressure level. The inline and the outlet valves are selectively opened by bi-directional air flow within the air passageway and dictated the forward and reverse directions in which the tire rotates. 
     While the above representations of the subject invention are as indicated in  FIGS. 3A through 3C ,  FIGS. 4A through 4C  and  FIGS. 5A through 5D , the invention is not limited to the embodiments shown. The four check valves used for directionality can be anywhere in the tire pumping channel  20 , attached to the tire inner liner surface  25 , attached to the surface of the regulator housing, or completely integrated into the regulator as shown. Such deviations are within the knowledge of those of ordinary skill in the art. Similarly, while the embodiments shown represent two-port and five-port regulator configurations, other embodiments may be substituted without departing from the scope of the invention. Three and four port regulators may be substituted if desired. It will further be noted that, in the regulator embodiments shown, the air flow direction within the regulator must always come through the inlet filter  34  and always follows opposite to the tire rotation outside the regulator. It will further be understood in the Bypass Regulator embodiment, that the bypass conduit connects the two check valves, outlet valves  106 ,  112 , that send high pressure compressed air into the tire. During the fill mode, air is not allowed to flow through the bypass passageway so long as the air pressure within the tire cavity is less than Preg. The air is thus directed to force open the outlet check valves and send the air into the tire. When the tire reaches the required pressure, the air is allowed to flow through the bypass valve. The air is thus circulated about the passageway  20  and through the regulator bypass passageway and is not compressed. Overfill of the tire cavity is thus prevented. 
     The reversible peristaltic tire and pump assembly will work for any configuration of air pump passageway and for an angle of the passageway relative to the tire up to a 360 degree annular circumference. The system is functional for built-in air passageways or post cure attached tube-based passageways. The inline and outlet check valves may be integrated into the regulator housing design. Both Bypass (third embodiment) and Inlet Control (first and second embodiments) regulators are possible. Moreover, no dead volume(s) of air are created in the middle of the air flow path. Rather, the air flow paths are symmetric the inlet and outlet may be exchanged interchangeably without compromising functionality. 
     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.