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 pumping device includes a housing attached to the tire rim, a dynamic mass mechanically confined to radial movement relative to the housing and the tire rim, an intake port for ambient to enter the housing, and an exhaust port for forcing air into a tire cavity of the pneumatic tire for restoring air loss from an inflation volume within the tire cavity.

What is claimed: 
     
         1 . A pumping device for use with a pneumatic tire mounted on a tire rim to keep the pneumatic tire from becoming underinflated, the pumping device comprising:
 a housing attached to the tire rim;   a dynamic mass mechanically confined to radial movement relative to the housing and the tire rim;   an intake port for ambient air to enter the housing; and   an exhaust port for forcing air into a tire cavity of the pneumatic tire for restoring air loss from an inflation volume within the tire cavity.   
     
     
         2 . The pumping device as set forth in  claim 1  wherein the dynamic mass is mechanically confined to radial movement within the housing. 
     
     
         3 . The pumping device as set forth in  claim 1  wherein the dynamic mass changes position corresponding to a rotational speed of the tire rim. 
     
     
         4 . The pumping device as set forth in  claim 1  wherein a plane about which the dynamic mass moves is coplanar with a rotational plane of the tire rim. 
     
     
         5 . The pumping device as set forth in  claim 1  wherein movement of the dynamic mass transfers work energy to air pressure in the housing. 
     
     
         6 . The pumping 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 housing. 
     
     
         7 . The pumping device as set forth in  claim 6  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 housing. 
     
     
         8 . The pumping device as set forth in  claim 7  further including a biasing element for returning the housing from a high volume intake condition to a low volume exhaust condition. 
     
     
         9 . The pumping device as set forth in  claim 8  wherein the first check valve and the second check valve are self checking ball-type check valves. 
     
     
         10 . The pumping device as set forth in  claim 1  further including a bladder receiving ambient air from within the housing and forcing pressurized air into the tire cavity. 
     
     
         11 . The pumping device as set forth in  claim 10  wherein the housing receives ambient air from an exterior of the housing and exhausts pressurized air to the tire cavity simultaneously. 
     
     
         12 . The pumping device as set forth in  claim 1  further including a lever arm pivoted by radial movement of the dynamic mass. 
     
     
         13 . The pumping device as set forth in  claim 12  further including a biasing member for restoring the dynamic mass to an initial position. 
     
     
         14 . The pumping device as set forth in  claim 1  further including a mechanical fastener for fixing the pumping device to the tire rim. 
     
     
         15 . The pumping device as set forth in  claim 1  further including an adhesive for fixing the pumping device to the tire rim. 
     
     
         16 . The pumping device as set forth in  claim 1  further including a second housing attached to the tire rim diametrically opposite the first housing. 
     
     
         17 . The pumping device as set forth in  claim 16  wherein the pumping device also restores air loss from an inflation volume within a second tire cavity of a second pneumatic tire. 
     
     
         18 . The pumping device as set forth in  claim 13  wherein the biasing member is attached to two tabs on the pumping device. 
     
     
         19 . The pumping device as set forth in  claim 18  further including additional biasing members added to additional tabs to increase the force restoring the dynamic mass to the initial position.