Diaphragm pump for self-inflating tire

A diaphragm pump for use in a self-inflating tire assembly is disclosed. The assembly includes a tire mounted to a rim tire mounting surface. The tire has an internal cavity. The invention further includes a pump device mounted to the rim, and the pump device has a first end and a second end, the first end being mounted within the tire cavity and the second end located outside the rim and in fluid communication with the outside air. The first end of the pump device has a flexible member having an outer rim and an inner rim, wherein the outer rim is connected to a backing plate and an inner rim is connected to a piston, wherein the piston is slidably mounted within a chamber of the backing plate. The piston has an inner passageway for fluid communication with the tire cavity and the chamber, and the second end of the pump device has an internal bore in fluid communication with the outside air and the chamber.