Patent Publication Number: US-2019184776-A1

Title: Pump assembly

Description:
FIELD OF THE INVENTION 
     The present invention relates to a pump system and method for maintaining appropriate air pressure within a pneumatic tire. More specifically, the present invention relates to a wheel mounted system for directing air into a tire cavity of a pneumatic tire. 
     BACKGROUND OF THE INVENTION 
     Conventional pneumatic tires are designed to perform for relatively long periods of time. In many cases, automobile tires are now expected to have a useful service life of 30,000, 50,000, or 70,000 miles. However, even long-life pneumatic tires are subject to air pressure losses due to puncture by nails and other sharp objects, temperature changes, and/or diffusion of air through the tire itself. 
     Since air diffusion reduces tire pressure over time, the pneumatic tires are often continually underinflated. Accordingly, drivers must repeatedly act to maintain tire pressures or fuel economy, tire life, and/or vehicle braking and handling performance will be reduced. Tire Pressure Monitoring Systems (TPMS) have been proposed to warn drivers when tire pressure is significantly low. Such systems, however, remain dependent upon a driver taking remedial action, when warned, to re-inflate a tire to the recommended pressure. It is desirable, therefore, to incorporate an air maintenance feature within a pneumatic tire that will maintain recommended air pressure without requiring bothersome driver intervention. 
     While pumping systems have been proposed, many are often too mechanically complex and costly. Consumers are not willing to pay for an expensive pump system. Thus, an improved simple, low cost pump that is easy to install is desired. The pump system must have a low-profile design so that is does not interfere with the mounting of the tire or other mechanical components. 
     SUMMARY OF THE INVENTION 
     A pumping mechanism in accordance with the present invention is used with a pneumatic tire mounted on a wheel to keep the pneumatic tire from becoming underinflated. According to a first aspect of the invention, a double acting pump mechanism is described for mounting on a wheel for inflating a pneumatic tire. The double acting pump mechanism includes a housing having a first pump chamber and a second pump chamber; wherein a diaphragm separates the first pump chamber from the second pump chamber; said housing further including an inlet port in fluid communication with the first pump chamber, and an outlet port in fluid communication with the second pump chamber, and wherein the outlet of the first pump chamber is in fluid communication with the inlet of the second pump chamber; a striker plate is positioned for reciprocation in the housing; said striker plate being connected to a diaphragm holder, wherein said diaphragm holder engages the diaphragm and actuates the diaphragm in the first and second pump chamber. Preferably the striker plate is actuated by a permanent or electro magnet mounted on a stationary part, or the striker plate is actuated by an electrically driven magnet. 
    
    
     
       DETAILED DESCRIPTION OF DRAWINGS 
       The following drawings are illustrative of examples of the present invention. 
         FIG. 1  is a perspective view of a wheel and pump system of the present invention. 
         FIG. 2  is a side view of the wheel of  FIG. 1  shown with the tire removed; 
         FIG. 3  is a cross-sectional view of the pump system in the direction  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a cross-sectional view of the pump system in the direction  4 - 4  of  FIG. 2 . 
         FIG. 5  is a close-up view of the pump system of  FIG. 4 ; 
         FIG. 6  is a schematic view of the pump system with the pumps connected in series; 
         FIG. 7  is an exploded view of a double action pump of the present invention; 
         FIG. 8A  is a perspective view of the double acting pump; 
         FIG. 8B  is a top view of the double acting pump; 
         FIG. 8C  is a cross-sectional view in the direction D-D of  FIG. 8B ; 
         FIG. 8D  is a cross-sectional view in the direction C-C of  FIG. 8B ; 
         FIG. 8E  is a cross-sectional view in the direction B-B of  FIG. 8B ; 
         FIG. 9A  is a perspective view of an electro magnet suitable for use with the present invention, while  FIG. 9B  illustrates the electromagnet assembled to the pump. 
         FIG. 10  is a schematic of an exemplary vehicle with tires having the pump of the present invention, and the location of the power receivers on the vehicle; 
         FIG. 11  is a schematic of the pump, micro-control system and power management system. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLES OF THE PRESENT INVENTION 
       FIGS. 1 through 5  illustrate a wheel  20  which houses a low-profile pump system  100  of the present invention. A conventional tire  10  is mounted on the wheel and encloses the pump system in the tire cavity. As shown in  FIG. 2 , the wheel  20  may be conventional. As shown in  FIG. 5 , the wheel  20  is preferably modified to include opposed grooves  30  located on the rim flange  40 . The groove is preferably U shaped or any desired shape that could easily mount a pump system therein. The low-profile pump system  100  is preferably received in the groove  30 . The pump system housing is designed to have a snap in fit in the groove  30 . A snap in insert  50  conceals the pump system on the outer wheel surface  60 . Preferably, the low-profile pump system  100  includes one or more low profile pumps  500 . Each low-profile pump  500  is mounted in a housing  300 . The outer surface  310  of the pump housing is preferably flush with the rim flange  40 . The low-profile pump  500  is designed to have a minimal height H in the radial direction when the pump is mounted on the rim flange. The radial height of the pump system is preferably minimized to less than or equal to the Tire and Rim Assembly or ETRTO defined standard tire rim well depth. 
     A low-profile pump preferable for use with the invention is a double acting diaphragm pump  500  as shown in  FIGS. 7 through 9 . The pump is preferably low profile having a minimized height H 2  in the radial direction. The pump  500  has an inlet port  512  and an outlet port  514  as shown in  FIG. 8B . An exploded view is shown in  FIG. 7 . The pump has a lower frame  510  that includes an inner chamber  511  for reciprocation of a strike plate  550  as shown in  FIG. 8E . The strike plate  550  is housed in the inner chamber  511  and is connected to reciprocating guide rods  560  that slide in bearing sleeves  730 . A resilient spring  565  is positioned between the upper end  561  of the guide rod and the upper support frame  520  for biasing the strike plate radially outward of the diaphragm  600 . The diaphragm pump  500  has two chambers, a first or radially outer chamber  620  and a second or radially inner chamber  630 . The two chambers are preferably in fluid communication with each other, so that the outlet air from the first chamber is fed into the inlet of the second chamber. The diaphragm  600  is affixed to a holder  620  by screw  610  and is positioned for reciprocation in each chamber  620 , 630 . The holder  620  is affixed to the strike plate  550 , so that the diaphragm reciprocates in the chambers  620 , 630  by actuation of the strike plate  550 . A gasket  820  and bearing collar  800  is received about the support holder  620 . 
     The pathway of the air is shown in  FIGS. 8D and 8E . Air enters the pump via inlet  512  and is fed into a first passageway  514  thru a one-way check valve  710 . The first passageway is in fluid communication with the radially outer or first chamber  620 . The compressed air exits through a second check valve  700  and then into lower passageway  516  that feeds the second chamber  630 . The lower passageway  516  is formed between the middle housing  520  and lower housing  510 . The compressed air then exits the check valve  720  into valve outlet  514 . 
     The driving force of the pump  500  may be a permanent magnet  400  that is placed on a fixed or stationary position near the wheel (i.e., does not rotate with the wheel), such as the brake system or suspension system as shown in  FIG. 1 . As shown in  FIGS. 2-3 , the pump housing is snap fit into opposed grooves  30  of a rim flange, so that the strike plate  550  is in electrical communication with the permanent magnet  400 . Preferably, the strike plate faces the permanent magnet  400 . Multiple permanent magnets  400  may be used at spaced apart intervals. 
     The driving force of the pump may also be from an electrically energized magnet or electromagnet  450  capable of being switched on and off as shown in  FIG. 9 a   . If an electric magnet  450  is used, then the pumping action is controlled by the energized action (on/off) of the electric magnet. The electric magnet  450  is preferably positioned adjacent the strike plate as shown in  FIG. 9B . The electromagnet has the advantage of providing fluid control of the system since it may be switched on and off.  FIG. 11  illustrates the pump  500  and electromagnet  450 , and how the electrical connection of each electromagnet  450  is achieved. Each electromagnet  450  on a given wheel is connected to a microcontroller  460 , wherein each microcontroller  460  has a built-in charging receiver and may include an optional Tire Pressure Monitoring System or TPMS unit. Each microcontroller  460  is mounted on the rim, inside the tire. The TPMS unit is configured from several components including pressure, temperature sensors to measure and communicate the tire pressure and tire temperature data. Each microcontroller receives power from a power receiver  470 , which is also mounted on the rim inside the tire. The power receiver  470  includes a wireless charging receiver, a rechargeable battery or a supercapacitor. Each power receiver  470  is in electrical communication with a wireless power charging transmitter  480 , that is preferably mounted on a vehicle. 
       FIG. 6  illustrates the pump system  100  with two or more double acting diaphragm pumps  500 ,  500 ′ wherein the pump chambers  620 , 630  are arranged in series, so that the outlet of a first pump chamber  620  is fed into the inlet of the second pump chamber  630 . Multiple pumps may additionally be used, and also connected in series. Preferably, a check valve  410  is located between each of the pump chamber connections to prevent backflow. Due to an amplification effect of connecting the pump passageways in series, the compression of the pump driving mechanism may be defined as: 
       R=(r) 2n            where   R: system compression ratio   r: single chamber compression ratio   n: number of pump in the system
 
Thus, a high compression ratio for each pump  500  is not necessary to achieve an overall high compression ratio of the pump system (e.g., low force and/or deformation may produce high compression). The pump system may also optionally include a filter  420 . The air inlet to the pump system maybe from a passageway in the valve stem, as describe in patent application No. 62/398,981 filed on Sep. 23, 2016 and application No. 15/707,052 filed on Sep. 18, 2017 (both of which are incorporated by reference in their entirety), or from a passageway in the rim. Air enters the tire cavity from the outlet of the last pump.
       
     In an alternate embodiment, any of the one or more pumps may be arranged in a groove on the wheel outside of the tire. 
     In an alternate embodiment, the driving force may be from the rotational energy of the wheel imparting energy to the strike plate or plunger plate. The mass of the strike plate or plunder sized to actuate as the wheel rotates. No magnet is needed. 
     The low-profile pump system as described herein have the advantage of a simple, low cost system that is easy to install on a wheel, and solves the problem of low tire pressure. The system is light, durable and provides a high driving force. The system may be used on consumer and commercial truck systems. 
     While certain representative examples and details have been shown for the purpose of illustrating the present invention, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the spirit or scope of the present invention.