Air maintenance tire assembly

Abstract

A pumping device is used with a pneumatic tire mounted on a tire rim to keep the pneumatic tire from becoming underinflated. The device includes a pumping device attached to the tire rim, a dynamic mass mechanically confined to rotational movement relative to the pumping device and the tire rim, the dynamic mass moving in response to a minimum angular acceleration and a minimum angular velocity of the tire rim and pumping ambient air into the pumping device, an intake port for ambient air to enter the pumping device, and an exhaust port for forcing pressurized air into a tire cavity of the pneumatic tire for restoring air loss from an inflation volume within the tire cavity, the dynamic mass and the pumping device both being weighted equally on each side of a centerline of the tire rim.

What is claimed: 
     
         1 . A device for use with a pneumatic tire mounted on a tire rim to keep the pneumatic tire from becoming underinflated, the device comprising:
 a pumping device attached to the tire rim;   a dynamic mass mechanically confined to rotational movement relative to the pumping device and the tire rim, the dynamic mass moving in response to a minimum angular acceleration and a minimum angular velocity of the tire rim and pumping ambient air into the pumping device;   an intake port for ambient air to enter the pumping device; and   an exhaust port for forcing pressurized air into a tire cavity of the pneumatic tire for restoring air loss from an inflation volume within the tire cavity, the dynamic mass and the pumping device both being weighted equally on each side of a centerline of the tire rim.   
     
     
         2 . The device as set forth in  claim 1  wherein the dynamic mass comprises ⅔ of the weight of the device and the pumping device comprises ⅓ of the weight of the device. 
     
     
         3 . The device as set forth in  claim 2  wherein the pumping device weighs between 100 grams and 300 grams. 
     
     
         4 . The device as set forth in  claim 1  wherein the pumping device further includes at least one extension arm extending laterally from the pumping device. 
     
     
         5 . The device as set forth in  claim 1  wherein the dynamic mass is angled radially inward from the pumping device when the dynamic mass engages the tire rim. 
     
     
         6 . The device as set forth in  claim 1  further including a second pumping device and a second dynamic mass are both mounted at a diametrically opposite location on the tire rim from the first pumping device and the first dynamic mass. 
     
     
         7 . The device as set forth in  claim 6  wherein both dynamic masses move simultaneously in response to angular accelerations/decelerations of the tire rim. 
     
     
         8 . The device as set forth in  claim 1  further including a biasing element for returning the dynamic mass to a position engaging the tire rim. 
     
     
         9 . The device as set forth in  claim 1  wherein the dynamic mass is mechanically confined to rotational movement relative to the pneumatic tire. 
     
     
         10 . The device as set forth in  claim 1  wherein the dynamic mass changes position corresponding to angular velocities of the tire rim rising above and moving below a predetermined angular velocity. 
     
     
         11 . The device as set forth in  claim 1  wherein a plane about which the dynamic mass rotates passes through an axis of rotation of the tire rim. 
     
     
         12 . The device as set forth in  claim 1  wherein pivoting movement of the dynamic mass transfers work energy to air pressure in the pumping device. 
     
     
         13 . The device as set forth in  claim 1  further including a first check valve disposed proximate to the intake port for preventing air from flowing out of the pumping device. 
     
     
         14 . The device as set forth in  claim 13  further including a second check valve disposed proximate to the exhaust port for preventing air from flowing out of the tire cavity and into the pumping device. 
     
     
         15 . The device as set forth in  claim 14  further including a biasing element for returning the pumping device from a high volume intake condition to a low volume exhaust condition. 
     
     
         16 . The device as set forth in  claim 15  wherein the first check valve and the second check valve are self checking ball-type check valves. 
     
     
         17 . The pumping device as set forth in  claim 1  wherein the dynamic mass pivots to pump pressurized air from the pumping device and forcing pressurized air into the tire cavity. 
     
     
         18 . The device as set forth in  claim 1  wherein the pumping device receives ambient air from an exterior of the pumping device and exhausts pressurized air into the tire cavity simultaneously. 
     
     
         19 . The device as set forth in  claim 1  wherein the pumping device also restores air loss from an inflation volume within a second tire cavity of a second pneumatic tire.