Air-drag powered devices are provided for automatically maintaining a target inflation pressure or for equipping vehicle wheels with additional functionality. One illustrative device embodiment is an air compressor that attaches to the wheel of a vehicle to turn with the wheel as the vehicle moves. A drag member extends from the body of the air compressor to alternately present opposing surfaces to the air through which the vehicle passes. The air drag on the member thus creates an alternating drag force that powers the air compressor. Another illustrative device embodiment is an energy harvester that attaches to the wheel of a vehicle to turn with the wheel as the vehicle moves. A drag member attached to the base of the energy harvester presents alternating surfaces to the air through which the vehicle passes to derive a reciprocating motion suitable for generating electricity usable for powering wheel-mounted sensors or lights.

A compression device for a self-inflating tire is provided that includes a first surface made from a flexible memory material, where the first surface is mechanically connected to a pumping chamber, where the first surface includes a first arm, a second arm and a fulcrum along an X-Y plane, where the fulcrum is disposed between the first arm and the second arm, an arc-shape length along a Y-Z plane that is configured to conform to an inner surface of a tire, a first state, where when in the first state, the first surface conforms to an unloaded, pressurized inner surface of the tire, and a second state, where when in the second state, the first surface collapses radially outward about the fulcrum by the first arm and the second arm, where air is drawn in from the atmosphere and pushed through the pumping chamber into the tire.

A compression device for a self-inflating tire is provided that includes a first surface made from a flexible memory material, where the first surface is mechanically connected to a pumping chamber, where the first surface includes a first arm, a second arm and a fulcrum along an X-Y plane, where the fulcrum is disposed between the first arm and the second arm, an arc-shape length along a Y-Z plane that is configured to conform to an inner surface of a tire, a first state, where when in the first state, the first surface conforms to an unloaded, pressurized inner surface of the tire, and a second state, where when in the second state, the first surface collapses radially outward about the fulcrum by the first arm and the second arm, where air is drawn in from the atmosphere and pushed through the pumping chamber into the tire.

The invention provides a method of mounting a device to a tire so that the device is mounted on a flat surface. The invention includes a shaped rubber patch having a flat mounting surface and a doubly curved lower surface. The shaped rubber patch is mounted inside the tire in such a way that the curved lower surface mates to the tire sidewall so that the device can be mounted on a flat surface. Because the curved lower surface of the patch mates with the tire curvature, a better attachment interface is provided.

In variants, a two-stage pump can include a piston and a cylinder cooperatively defining a first stage in front of the piston fluidly connected to a second stage behind the piston, wherein a forward stroke of the piston pressurizes working fluid in the first stage and forces pressurized working fluid into the second stage, and a backward stroke of the piston further pressurizes working fluid in the second stage and exhausts pressurized working fluid out a pump exhaust.

In variants, a two-stage pump can include a piston and a cylinder cooperatively defining a first stage in front of the piston fluidly connected to a second stage behind the piston, wherein a forward stroke of the piston pressurizes working fluid in the first stage and forces pressurized working fluid into the second stage, and a backward stroke of the piston further pressurizes working fluid in the second stage and exhausts pressurized working fluid out a pump exhaust.