Tire pressure maintenance device

• US 20070151648A1
• Filed: 02/27/2007
• Published: 07/05/2007
• Est. Priority Date: 11/12/2004
• Status: Active Grant

• Current Assignee: Richard Loewe
• Original Assignee: Richard Loewe
• Inventors: Loewe, Richard
• Granted Patent: US 7,784,513 B2
• Time in Patent Office: Days
• US Class Current: 152/419
• CPC Class Codes: B60C 23/004 the control being done on the wheel, e.g. using a wheel-mounted reservoir
• CPC Class Codes: B60C 23/041 Means for supplying power to the signal- transmitting means on the wheel
• CPC Class Codes: B60C 23/0413 Wireless charging of active radio frequency circuits
• CPC Class Codes: B60C 23/043 using transformer type signal transducers, e.g. rotary transformers
• CPC Class Codes: B60C 23/126 the pumps being mounted on the wheel rims
• CPC Class Codes: B60C 23/129 the pumps being mounted on wheel spokes

Abstract

A device for maintaining a desired inflation pressure within a tire mounted on a wheel of a vehicle which includes a microcompressor having a flexible compression chamber and a magnetic element not on the wheel. As the compressor passes the magnet each wheel revolution, a small amount of atmospheric air is pumped into the tire, if needed. The magnet and the compressor need no other contact with the vehicle or the wheel and require no energy source on the wheel. An alternative embodiment uses an electrical coil on the wheel to pass the magnet inducing a voltage that drives a compressor on the wheel. As the coil passes the electromagnet it provides a split transformer that transfers electrical power to the wheel and permits two-way pulse data communication between the wheel and the vehicle.

Claims

1. A device for maintaining a desired inflation pressure of an interior of a tire mounted on a wheel of a vehicle, the wheel being rotatably connected to a stationary member of a vehicle wheel assembly and defining an axis of rotation, the device comprising:

at least one magnetic element being mounted on the stationary member at a radial distance from the axis of rotation, the magnetic element producing a magnetic field wherein the magnetic element produces at least one of two opposing forces;

a magnetically driven air compressor being mounted on the wheel and being radially disposed from the axis of rotation relative to the magnetic element to transit the magnetic field during each revolution of the wheel, the compressor being in fluid communication with the atmosphere and the interior of the tire, the compressor being operative to intake air from the atmosphere and to output compressed air to the interior of the tire in response to transiting the magnetic field wherein the compressor includes a flexible compression chamber defining a variable chamber volume; and

means for regulating output pressure of the compressor to the desired inflation pressure without off-wheel aid;

an actuator being operative to increase and decrease the chamber volume, the actuator being operative to effect an intake stroke to increase chamber volume and thereby intake air from the environment through an intake check valve, the actuator further being operative to effect an output stroke to decrease chamber volume and thereby expel air through an output check valve; and

means for applying first and second opposing forces alternately to the actuator, one of the first and second opposing forces increasing the volume of the flexible chamber and the other of the first and second opposing forces decreasing the volume of the flexible chamber, at least one of the first and second opposing forces being produced upon transit of the compressor through the magnetic field.

2. The device of claim 1 wherein the flexible compression chamber is a bellows configuration having two opposing ends and flexible side walls, the first opposing end being in communication with the intake check valve and the second opposing end being in communication with the output check valve, the actuator being operative to increase the chamber volume to intake air into the compression chamber through the intake valve upon the actuator moving to an intake position during the intake stroke, the actuator being further operative to decrease the chamber volume and expel compressed air from the compression chamber through the output valve upon moving to an output position during the output stroke, one of the input stroke and output stroke being performed in response to the compressor transiting the magnetic field.

3. The device of claim 1 wherein the flexible compression chamber is bounded on one side by a flexible diaphragm, and being operative to increase the chamber volume to intake air into the compression chamber through the intake valve upon the actuator moving to an intake position during the intake stroke, the actuator further being operative to decrease the chamber volume and expel compressed air from the compression chamber through the output valve upon moving to an output position during the output stroke, one of the input stroke and output stroke being performed in response to the compressor transiting the magnetic field.

4. The device of claim 3, wherein the flexible diaphragm further comprises ferromagnetic particles embedded in the flexible diaphragm wherein the flexible diaphragm serves as the actuator.

5. The device of claim 1 including two stationary magnetic elements and wherein the compressor transits through two magnetic fields produced by the magnetic elements during one revolution of the wheel, both magnetic fields exerting the first opposing force upon the actuator to perform one of the input and output strokes, the second opposing force being exerted upon the actuator to perform the other of the input and output strokes as the compressor moves intermediate the magnetic elements, the alternate exertion of the first and second opposing forces causing the chamber volume to increase and decrease twice during one wheel revolution.

6. The device of claim 1, wherein the compressor transits magnetic fields of opposite polarity causing sequential opposing magnetic forces on a magnetized actuator.

7. The device of claim 6, wherein the magnetic fields of opposite polarity originate from opposite poles of one or more permanent magnets.

8. The device of claim 6, wherein the magnetic fields of opposite polarity are created by reversing the direction of current through one or more electromagnetic elements after the compressor transits at least one of the magnetic fields.

9. The device of claim 1 wherein a plurality of magnetic elements are configured to produce successive magnetic fields of opposite polarity through which the compressor transits during one revolution of the wheel, the input and output strokes being effected by the magnetized actuator in response to the magnetic fields of opposing polarity.

10. The device of claim 1 wherein the second opposing force is a continuous bias force being produced by one or more permanent magnets, the second opposing force being configured to be overcome by the first opposing force produced when the compressor transits the magnetic field of the stationary magnetic element, the second opposing force causing the actuator to effect one of the input and output strokes after transiting the magnetic field.

11. The device of claim 1 wherein the second opposing force is a bias force being produced by a spring biasing member, the second opposing force being configured to be overcome by the first opposing force produced when the compressor transits the magnetic field of the stationary magnetic element, the second opposing force causing the actuator to effect one of the input and output strokes after transiting the magnetic field.

12. The device of claim 1 wherein the second opposing force is the centrifugal force being continuously exerted upon the actuator due to rotation of the compressor about the axis of rotation of the wheel, the second opposing force causing the actuator to effect one of the input and output strokes after transiting the magnetic field.

13. The device of claim 1 wherein the second opposing force is configured to establish and regulate the desired inflation pressure of the tire.

14. The device of claim 1 wherein the compressor further includes an output port and a pressure limit valve, the output port being in fluid communication with the flexible compression chamber with the output valve being open, the pressure limit valve being in fluid communication with one of the output port and the flexible compression chamber, the pressure limit valve being operative to reduce the output pressure of air within the respective one of the output port and the flexible compression chamber to the desired tire inflation pressure by releasing air from the respective one of the output port and the flexible compression chamber to one of the atmosphere and intake plenum when the output pressure exceeds the desired tire inflation pressure.

15. The device of claim 1 wherein the means for regulating the output pressure of the compressor permits manual adjustment of the desired tire inflation pressure.

16. The device of claim 1 wherein the means for regulating the output pressure of the compressor varies the desired inflation pressure as a function of temperature of the air in the tire.

17. The device of claim 16 wherein the desired inflation pressure changes with the temperature of air in the tire tending to maintain a constant mass of air in the tire.

18. The device of claim 1 wherein the compressor includes an intake port and a centrifugal valve, the intake port being in fluid communication with the atmosphere, the centrifugal valve being operative to shut off all air and fluid entry into the compressor via the intake port while the wheel is rotating below a predetermined speed.

19. The device of claim 1 wherein the magnetic element is an electromagnet controlled by a central controller on the vehicle frame that receives electrical current from a vehicle battery and sends the current through the electromagnet winding to produce the magnetic field, the central controller being further operative to produce the current only during periods when the compressor is transiting the magnetic field.

20. A device for maintaining a desired inflation pressure within a tire mounted on the wheel of a vehicle, the wheel being rotatably connected to a stationary member of a vehicle wheel assembly and defining an axis of rotation, the device comprising:

at least one magnetic element being mounted on the stationary member at a radial distance from the axis of rotation, the magnetic element producing a magnetic field;

an electrical coil mounted on the wheel and being radially disposed from the axis of rotation relative to the magnetic element to pass through the magnetic field during a revolution of the wheel, the coil being operative to induce electrical voltage variations in response to the transit of the magnetic field and to output the electrical voltage variations for powering the device;

an air compressor mounted on the wheel being powered by electrical voltage variations induced in the coil by transiting the magnetic field, the air compressor in electrical communication with the coil and in fluid communication with the atmosphere and an interior of the tire, the compressor further operative to output compressed air into the tire;

electronic elements that alert a vehicle driver to tire pressure conditions and

means for regulating the output pressure of the air compressor to the desired tire inflation pressure without off-wheel aid.

21. The device of claim 20, further comprising an adjustable pressure limit switch in electrical communication with the electrical coil and the air compressor, the pressure limit switch being activated by tire pressure and operative to regulate the desired inflation pressure of the tire.

22. The device of claim 20, wherein the means of regulating the output pressure of the compressor varies the desired inflation pressure as a function of the temperature of air in the tire.

23. The device of claim 21, wherein the desired inflation pressure is varied as a function of the temperature of the air in the tire so as to maintain a constant mass of air in the tire.

24. The device of claim 20, wherein the magnetic element is an electromagnet operative to generate a current to produce the magnetic field only when the electrical coil is transiting the magnetic field during the rotation of the wheel.

25. The device of claim 20, further comprising an electrical power supply that receives output from the electric coil and converts the output from the electrical coil into electrical power usable by at least one of the air compressor and the on-wheel electronics.

26. The device of claim 25, further comprising an on-wheel rechargeable electrical storage device configured to store electrical power for at least one of the air compressor and the on-wheel electronics.

27. The device of claim 20, wherein the magnetic element is an electromagnet that serves as a primary winding of an intermittent split transformer with the electrical coil forming a secondary winding of the split transformer, the split transformer being operative while the primary and secondary windings are in magnetic communication, the split transformer being operative to perform one of transferring electrical power from the vehicle to the wheel and providing two-way pulse data communication between the vehicle and the wheel.

28. The device of claim 27 further comprising:

an on-wheel power supply operative to receive the voltage output of the secondary winding and to convert the voltage output to an electrical form needed to satisfy electrical power needs for at least one of the compressor and the on-wheel electronics;

a driver display being operative to inform a driver of a suspected leak or failure of a given wheel;

a central controller mounted on the vehicle and operative to send and receive pulse coded data to and from the primary winding while the transformer is operative;

the central controller being in electrical communication with a vehicle battery, the primary winding, and the driver display;

the central controller being operative to determine when compressor operation is high enough to suspect a leak or low enough to suspect a failure, the central controller being operative to send data to the driver display being representative of the compressor operation;

an on-wheel controller operative to send and receive pulse coded data to and from the secondary winding while the transformer is operative;

the on-wheel controller being in electrical communication with the secondary winding, the on-wheel power supply, and the compressor;

the on-wheel controller being operative to sense compressor operation and to maintain the desired tire pressure, the on-wheel controller further being operative to send data corresponding to the compressor operation to the central controller and means for communicating the pulse coded data between the vehicle and the wheel assembly.

29. The device of claim 28, further comprising a rechargeable electrical storage device in electrical communication with the on-wheel power supply, the rechargeable electrical storage device operative to store electrical power and operate as a filter and D.C. source for providing reserve power to operate the compressor at a high speed when a failure is suspected.

30. The device of claim 28, further comprising tire sensors being operative to sense tire pressure and tire temperature, the sensors being disposed on each wheel and being in electrical communication with the on-wheel power supply and the on-wheel controller;