Abstract:
An apparatus for regulating air pressure level in a tire is provided herein. The apparatus includes a housing attached to the tire; a piston located inside the housing, coupled to the housing via a spring; a one-way valve; and locking elements located at a specified location along said housing, wherein the piston is configured to move towards a first end of the housing responsive to an imbalance between centrifugal force applied to the piston due to angular speed of the tire and force applied thereto by the spring means, wherein the locking elements are configured to lock the piston at the specified location whenever the tire reaches a predefined angular speed, and release the piston once the angular speed of the tire crosses a predefined threshold, so that said piston moves towards a second end of the sleeve producing an air pulse, conveyed by the one-way valve into the tire.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates generally to a self-pressure tire regulator and, more specifically, to a mechanism incorporating solely on mechanical parts. 
         [0003]    2. Discussion of Related Art 
         [0004]    Air diffusion reduces tire pressure over time. The natural state of tires is under-inflated and maybe even over-inflated due to wrongfully maintenance. Accordingly, drivers must repeatedly act to maintain tire pressure or they will cause higher fuel consumption per kilometer, tire life reduction, vehicle handling lower performance and vehicle braking lower performance. Tire Pressure Monitoring Systems (TPMS) have been proposed to warn drivers when tire pressure is significantly low or high. Such systems, however, remain dependent upon the driver taking corrective action when warned to re-inflate a tire to recommended pressure. 
         [0005]    Air temperature in a tire has a major effect on the pressure of air in the tire that must be considered in any approach to tire pressure maintenance. Ambient temperature variations and tire heating from rolling make tire temperatures and pressures denoting the amount of air in the tire. The pressure in a tire increases and decreases about 1 PSI with temperature increases and decreases of about 6° C. Normally, as a vehicle is driven the temperature in the tire increases due to the heat caused by friction from road contact and flexing of the side-walls causing a 2 to 5 PSI above its “cold” pressure (at ambient temperature). In addition, in practice tires are usually filled less often and while warm from driving. An ambient temperature drop of about 30° C., possible within a day and common within a month, reduces tire pressure by about 5 PSI. Thus, tire pressures frequently fall 8 PSI below the manufactures&#39; requirement, typically 25%, without considering the normal leak rate of about 1 PSI per month. 
         [0006]    Prior art presents a vast variety of self-inflating tire devices. The industry has attempted to solve the problem by offering electrical, electro-mechanical or mechanical devices, which work in association with such as U.S. Pat. No. 5,846,354, titled “tire pressure maintenance system”, where a gas transfer system is described that includes; power source, a pressure sensor, a control unit, and a gas transfer mechanism. Another example to this approach may be found in U.S. Pat. No. 5,558,730, titled “vehicle wheel including self-inflating tire pump”, where a pump is located inside the tire inflation region, provides a fixed tire pressure, comprised of many mechanical elements and requires a dedicated rim design. 
         [0007]    It is desirable, therefore, to incorporate an automatic self-pressure regulator feature within the tire or as an add-on that will self-inflate the tire in order to compensate for any reduction in the tire pressure over time without a need for driver intervention. The automatic self-pressure regulator feature must also be small, simple, practical and inexpensive and that provides long term reliable operation (i.e. is fail safe such that failures do not cause deflation or over-inflation of a tire). 
       BRIEF SUMMARY 
       [0008]    In accordance with the present invention, a self-pressure regulator is fixed to a wheel of a vehicle for automatically pumping air into an inflation region of a tire up to a desired pressure level. 
         [0009]    Self-pressure regulator includes a piston which is radially outward in a cylinder by centrifugal force to thrust air from the atmosphere into the inflation region upon release. 
         [0010]    A stopper mechanism (locking elements) prevents the piston from moving inward (e.g. wheel center) as long as the wheel rotates above a certain speed (velocity threshold). 
         [0011]    Upon release takes place as the vehicle speed is lower than the certain speed (velocity threshold), whereas the piston is released from the stopper mechanism (locking elements). 
         [0012]    A calibration mechanism in the self-pressure regulator provides a method of adjusting the preferred/desired pressure of the inflation region. 
         [0013]    Self-pressure regulator feature maybe located within the rim or as an add-on. 
         [0014]    These, additional, and/or other aspects and/or advantages of the present invention are: set forth in the detailed description which follows; possibly inferable from the detailed description; and/or learnable by practice of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention will be more readily understood from the detailed description of embodiments thereof made in conjunction with the accompanying drawings of which: 
           [0016]      FIG. 1  is a view of a self-pressure regulator tire mechanism and a tire in accordance with some embodiments of the present invention; 
           [0017]      FIG. 2  is a view of a self-pressure regulator tire mechanism and a tire cross-section in accordance with some embodiments of the present invention; 
           [0018]      FIG. 3  is an assembly view of a self-pressure regulator tire mechanism in accordance with some embodiments of the present invention; 
           [0019]      FIG. 4  describes a flow chart of an embodiment of the self-pressure regulator tire mechanism in accordance with some embodiments of the present invention; 
           [0020]      FIG. 5  is a view of a self-pressure regulator tire mechanism in a released state in accordance with some embodiments of the present invention; 
           [0021]      FIG. 6  is a view of a self-pressure regulator tire mechanism in a tensed state in accordance with some embodiments of the present invention; 
           [0022]      FIG. 7  is a view of an invert self-pressure regulator tire mechanism and a tire in accordance with some embodiments of the present invention; 
           [0023]      FIG. 8  is a view of an invert self-pressure regulator tire mechanism and a tire cross-section in accordance with some embodiments of the present invention; 
           [0024]      FIG. 9  is an assembly view of an invert self-pressure regulator tire mechanism in accordance with some embodiments of the present invention; 
           [0025]      FIG. 10  describes a flow chart of an invert embodiment of the self-pressure regulator tire mechanism in accordance with some embodiments of the present invention; 
           [0026]      FIG. 11  is a view of an invert self-pressure regulator tire mechanism in a released state in accordance with some embodiments of the present invention; 
           [0027]      FIG. 12  is a view of an invert self-pressure regulator tire mechanism in a tensed state in accordance with some embodiments of the present invention; and 
           [0028]      FIG. 13 - FIG. 15  are a view of two invert self-pressure regulator tire mechanism and a tire in accordance with some embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is applicable to other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. 
         [0030]    In accordance with the present invention,  FIG. 1  and  FIG. 2  illustrate a wheel  30  for a vehicle such as an automobile includes a body  31  having an outer peripheral rim  32  on which a tire  33  is mounted. An annular inflation region  34  is defined inside the tire  33  by the inner wall of the tire  33  and the rim  32 . A single self-pressure regulator tire  10  embodying the invention maybe mounted externally on the rim  32  or in another option, as an add-on device. In both mounting options, self-pressure regulator tire  10  pumps and/or regulates air from the atmosphere into the annular inflation region  34 . 
         [0031]    A single self-pressure regulator tire  10  is illustrated as being mounted on the rim  32 . However, an additional element and/or elements maybe mounted at an opposed position on the rim  32  to provide counterbalance as to the single self-pressure regulator tire  10 . 
         [0032]    A schematic diagram of self-pressure regulator tire  10  is illustrated in  FIG. 3 . An air pipe  23  is connected to the tire  33  inflation region  34  providing it with thrust air from the atmosphere. For an add-on mounting option of self-pressure regulator tire  10  the air pipe  23  is connected via the tire  33  valve. For an integral mounting option of self-pressure regulator tire  10  (i.e. self-pressure regulator tire  10  maybe located as part of the rim  32 ) no air pipe  23  is required. 
         [0033]    A bottom cover  22  includes a connection to the air pipe  23  (if applicable) and a one-way air in valve  16 . Air from the atmosphere is sucked/drawn via the one-way air valve  16 . In addition, one-way air release valve  35  has the role of releasing thrust air (to the atmosphere or to a storage chamber not illustrated) once tire inflation region  34  pressure is equal or above the desired pressure produced by self-pressure regulator tire  10 . 
         [0034]    On the outer part of a housing  21  of the device (referred hereinafter a “the main sleeve” or simply “sleeve”) at least a single locking element  14  comprising of at least a single torsion spring  24  are connected. A piston  15  may move freely in this main sleeve  21 . An air chamber is created between the sealing ring  25  (or any other means of sealing between the piston  15  and the main sleeve  21 ) on the piston  15  through the inner volume of the bottom cover  22  to the tire  33  valve. Torsion spring  24  has the role of pushing locking element  14  perpendicular as to main sleeve  21 . As long as external piston  13  is up (i.e. not covering locking element  14 ) torsion spring  24  is in locked condition (default situation). 
         [0035]    Spring  20  has the role of converting the centrifugal force (due to wheel  30  rotation) and work (due to the displacement of the piston  15 ) into potential energy which is then converted into kinetic work by releasing the piston  15  from stopper mechanism (locking elements  14 ). 
         [0036]    External piston  13  may move radially outward (i.e. in direction of calibration screw  27 ) by centrifugal force to enable locking elements  14  a free move. External spring  29  has the role of retrieving external piston  13  inward (i.e. in direction of bottom cover  22 ) once vehicle speed has reduced its speed less than a certain speed (velocity threshold VTHRESHOLD). As external piston  13  passes (due to external spring  29  potential energy) locking elements  14 ; piston  15  is released from stopper mechanism (locking elements  14 ) and thrust pressurized air. A top ring  28  is located in the upper side of self-pressure regulator tire  10  preventing external spring  29  to pop out. 
         [0037]    A calibration mechanism in the self-pressure regulator tire  10  provides a method of adjusting the preferred/desired pressure of the inflation region  34 . This calibration mechanism may be implemented by a calibration screw  27 . Spring  20  span (free movement) which is directly related to the inflation pressure provided by self-pressure regulator tire  10  is adjusted via calibration screw  27 . Self-pressure regulator tire  10  provides; lower pressure inflation while calibration screw  27  is outward as to higher pressure inflation while calibration screw  27  is inward (i.e. in direction of bottom cover  22 ). 
         [0038]      FIG. 4  illustrates a flow chart of a self-pressure regulator tire mechanism  10 . In released state  40 , main piston  15  is not locked by stopper mechanism (locking elements  14 ) which is directly related to vehicle velocity (i.e. tire radial speed). Main piston  15  cannot reach stopper mechanism (locking elements  14 ) due to the low centrifugal force which does not overcome the main piston  15  spring  20  constant force. A threshold is set which is defined as a certain vehicle speed (velocity threshold VTHRESHOLD for example VTHRESHOLD=40 km per hour) in which the piston  15  spring  20  constant force is similar to the centrifugal force (neglecting tension losses for simplicity reasons). 
         [0039]    As long as the vehicle speed is lower than velocity threshold (V&lt;VTHRESHOLD for example VTHRESHOLD=40 km per hour and V=30 km per hour) self-pressure regulator tire mechanism  10  shall remain 43 in released state  40 . 
         [0040]    Once the vehicle speed is above velocity threshold (V&gt;VTHRESHOLD for example VTHRESHOLD=40 km per hour and V=45 km per hour) self-pressure regulator tire mechanism  10  shall transit  44  to tensed state  41 . In tensed state  41 , main piston  15  is locked by stopper mechanism (locking elements  14 ) which is directly related to vehicle velocity (i.e. tire radial speed). External piston  13  has passed stopper mechanism (locking elements  14 ) due to the high centrifugal force which overcomes the external piston  13  spring  29  constant force. In addition, main piston  15  has passed stopper mechanism (locking elements  14 ) due to the high centrifugal force which overcomes the main piston  15  spring  20  constant force. 
         [0041]    As long as the vehicle speed is above than velocity threshold (V&gt;VTHRESHOLD for example VTHRESHOLD=40 km per hour and V=50 km per hour) self-pressure regulator tire mechanism  10  shall remain 45 in tensed state  41 . 
         [0042]    Once the vehicle speed has been reduced below velocity threshold (V&lt;VTHRESHOLD for example VTHRESHOLD=40 km per hour and V=38 km per hour) self-pressure regulator tire mechanism  10  shall transit  46  to inflation state  42 . In inflation state  42 , external spring  29  potential energy overcomes centrifugal force; pushing external piston  13  inward (i.e. in direction of bottom cover  22 ) and releasing stopper mechanism (locking elements  14 ). In addition, main piston  15  is released from stopper mechanism (locking elements  14 ). Upon release, main piston  15  overcomes the current centrifugal force which is lower than the potential energy of main piston  15  spring  20 . Air is being thrust from the pressure chamber of main sleeve  21  via bottom cover  22 , air pipe (if applicable) to the tire  33  valve. 
         [0043]    After inflation state  42  (vehicle speed is below velocity threshold V&lt;VTHRESHOLD) self-pressure regulator tire  10  returns  47  to released state  40 . 
         [0044]    In case inflation region  34  pressure is equal or higher than desired self-pressure regulator tire  10  inflation pressure the thrust air is released via release valve  35  (to the atmosphere or to a storage chamber not illustrated). 
         [0045]      FIG. 5  is a view of a self-pressure regulator tire mechanism  10  in a released state  40 . Main piston  15  is down (i.e. closer to bottom cover  22  as to calibration screw  27 ) and external piston  13  is also down, covering stopper mechanism (locking elements  14 ). A one direction valve  36  maybe introduced to self-pressure regulator tire mechanism  10  which has the role of preventing tire pressure in the inflation region  34  to leak out via the mechanism. 
         [0046]      FIG. 6  is a view of a self-pressure regulator tire mechanism  10  in a tensed state  41 . Main piston  15  is up (i.e. closer to calibration screw  27  as to bottom cover  22 ) and external piston  13  is also up, uncovering stopper mechanism (locking elements  14 ). In addition, main piston  15  is locked by stopper mechanism (locking elements  14 ). 
         [0047]    In accordance with the present invention,  FIG. 7  and  FIG. 8  illustrate a wheel  30  for a vehicle such as an automobile includes a body  31  having an outer peripheral rim  32  on which a tire  33  is mounted. An annular inflation region  34  is defined inside the tire  33  by the inner wall of the tire  33  and the rim  32 . A single invert self-pressure regulator tire  50  embodying the invention maybe mounted externally on the rim  32  or in another option, as an add-on device. In both mounting options, invert self-pressure regulator tire  50  pumps and/or regulates air from the atmosphere into the annular inflation region  34 . 
         [0048]    A single invert self-pressure regulator tire  50  is illustrated as being mounted on the rim  32 . However, an additional element and/or elements maybe mounted at an opposed position on the rim  32  to provide counterbalance as to the single invert self-pressure regulator tire  50 . 
         [0049]    A schematic diagram of invert self-pressure regulator tire  50  is illustrated in  FIG. 9 . An air pipe  23  is connected to the tire  33  inflation region  34  providing it with thrust air from the atmosphere. For an add-on mounting option of invert self-pressure regulator tire  50  the air pipe  23  is connected via the tire  33  valve. For an integral mounting option of invert self-pressure regulator tire  50  (i.e. invert self-pressure regulator tire  50  maybe located as part of the rim  32 ) no air pipe  23  is required. 
         [0050]    A bottom cover  22  includes a connection to the air pipe  23  (if applicable) and a one-way air in valve  16 . Air from the atmosphere is sucked/drawn via the one-way air valve  16 . In addition, one-way air release valve  35  has the role of releasing thrust air (to the atmosphere or to a storage chamber not illustrated) once tire inflation region  34  pressure is equal or above the desired pressure produced by invert self-pressure regulator tire  50 . 
         [0051]    On the outer part of the main sleeve  21  at least a single locking element  14  comprising of at least a single torsion spring  24  are connected. A piston  15  may move freely in this main sleeve  21 . An air chamber is created between the sealing ring  25  (or any other means of sealing between the piston  15  and the main sleeve  21 ) on the piston  15  through the inner volume of the bottom cover  22  to the tire  33  valve. Torsion spring  24  has the role of pushing locking element  14  perpendicular as to main sleeve  21 . As long as external piston  13  is up (i.e. not covering locking element  14 ) torsion spring  24  is in locked condition (default situation). 
         [0052]    Extension spring  70  has a role of pulling and returning the inner piston  15  from the bottom of the main sleeve  21  upwards (to the center of the wheel) to the locking elements  14  in low velocity (when the centrifugal force is negligible). 
         [0053]    External piston  13  may move radially outward (i.e. in direction of bottom cover  22 ) by centrifugal force to enable locking elements  14  a free move. External extension spring  79  has the role of retrieving external piston  13  inward (i.e. in direction of calibration screw  27 ) once vehicle speed has reduced its speed less than a certain speed (velocity threshold VTHRESHOLD). As external piston  13  passes (due to external extension spring  79  potential energy) locking elements  14 ; piston  15  is released from stopper mechanism (locking elements  14 ) and thrust pressurized air. A top ring  28  is located in the upper side of invert self-pressure regulator tire  50  preventing external extension spring  79  to pop out. 
         [0054]    A calibration mechanism in the invert self-pressure regulator tire  50  provides a method of adjusting the preferred/desired pressure of the inflation region  34 . This calibration mechanism may be implemented by a calibration screw  27 . Extension spring  70  span (free movement) which is directly related to the inflation pressure provided by invert self-pressure regulator tire  50  is adjusted via calibration screw  27 . Invert self-pressure regulator tire  50  provides; lower pressure inflation while calibration screw  27  is outward as to higher pressure inflation while calibration screw  27  is inward (i.e. in direction of bottom cover  22 ). 
         [0055]      FIG. 10  illustrates a flow chart of an invert self-pressure regulator tire mechanism  50 . In released state  62 , main piston  15  is not locked by stopper mechanism (locking elements  14 ) which is directly related to vehicle velocity (i.e. tire radial speed). Main piston  15  cannot reach stopper mechanism (locking elements  14 ) due to the high centrifugal force which overcomes the main piston  15  extension spring  70  constant force. A threshold is set which is defined as a certain vehicle speed (velocity threshold VTHRESHOLD for example VTHRESHOLD=40 km per hour) in which the piston  15  extension spring  70  constant force is similar to the centrifugal force (neglecting tension losses for simplicity reasons). 
         [0056]    As long as the vehicle speed is equal or above velocity threshold (V&gt;VTHRESHOLD for example VTHRESHOLD=40 km per hour and V=45 km per hour) invert self-pressure regulator tire mechanism  50  shall remain 65 in released state  62 . 
         [0057]    Once the vehicle speed is lower than velocity threshold (V&lt;VTHRESHOLD for example VTHRESHOLD=40 km per hour and V=35 km per hour) invert self-pressure regulator tire mechanism  50  shall transit  67  to tensed state  60 . In tensed state  60 , main piston  15  is locked by stopper mechanism (locking elements  14 ). External piston  13  has passed stopper mechanism (locking elements  14 ) due to the low centrifugal force which does not overcome the external piston  13  extension spring  79  constant force. In addition, main piston  15  has passed stopper mechanism (locking elements  14 ) due to the low centrifugal force which does not overcome the main piston  15  extension spring  70  constant force. 
         [0058]    As long as the vehicle speed is lower than velocity threshold (V&lt;VTHRESHOLD for example VTHRESHOLD=40 km per hour and V=20 km per hour) invert self-pressure regulator tire mechanism  50  shall remain 63 in tensed state  60 . 
         [0059]    Once the vehicle speed is above velocity threshold (V&gt;VTHRESHOLD for example VTHRESHOLD=40 km per hour and V=42 km per hour) invert self-pressure regulator tire mechanism  50  shall transit  64  to inflation state  61 . In inflation state  61 , external spring  29  potential energy does not overcome centrifugal force; pushing external piston  13  inward (i.e. in direction of bottom cover  22 ) and releasing stopper mechanism (locking elements  14 ). In addition, main piston  15  is released from stopper mechanism (locking elements  14 ). Upon release, main piston  15  overcomes the current centrifugal force which is lower than the potential energy of main piston  15  extension spring  70 . Air is being thrust from the pressure chamber of main sleeve  21  via bottom cover  22 , air pipe (if applicable) to the tire  33  valve. 
         [0060]    After inflation state  61  (vehicle speed is equal or above velocity threshold V&gt;VTHRESHOLD) invert self-pressure regulator tire  50  returns  66  to released state  62 . 
         [0061]    In case inflation region  34  pressure is equal or higher than desired invert self-pressure regulator tire  50  inflation pressure the thrust air is released via release valve  35  (to the atmosphere or to a storage chamber not illustrated). 
         [0062]      FIG. 11  is a view of an invert self-pressure regulator tire mechanism  50  in a released state  60 . Main piston  15  is down (i.e. closer to bottom cover  22  as to calibration screw  27 ) and external piston  13  is also down, covering stopper mechanism (locking elements  14 ). A one direction valve  36  maybe introduced to self-pressure regulator tire mechanism  10  which has the role of preventing tire pressure in the inflation region  34  to leak out via the mechanism. 
         [0063]      FIG. 12  is a view of an invert self-pressure regulator tire mechanism  50  in a tensed state  60 . Main piston  15  is up (i.e. closer to calibration screw  27  as to bottom cover  22 ) and external piston  13  is also up, uncovering stopper mechanism (locking elements  14 ). In addition, main piston  15  is locked by stopper mechanism (locking elements  14 ). 
         [0064]    In accordance with the present invention,  FIG. 12 - FIG. 15  illustrate a wheel for a vehicle with two invert self-pressure regulator tire  70  embodying the invention. Invert self-pressure regulator tire  70  has a similar mechanism as invert self-pressure regulator tire  50  except pressured air is located in the radial sleeve. 
         [0065]    While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the preferred embodiments. Other possible variations, modifications, and applications are also within the scope of the invention.