System and method for monitoring a pneumatic tire

• US 5,731,516 A
• Filed: 05/02/1996
• Issued: 03/24/1998
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: BMW of North America LLC (Bayerische Motoren Werke AG), Ford Motor Company, American Honda Motor Co., Inc. (Honda Motor Company), Hyundai Motor America (Hyundai Motor Group), Jaguar Land Rover North America LLC (Jaguar Land Rover Limited), MHL Tek LLC, Mitsubishi Motors North America Incorporated (Mitsubishi Materials Corporation), General Motors Corporation (Motors Liquidation Co. GUC Trust), Nissan North America Incorporated (Nissan Motor Co., Ltd.), Fuji Heavy Industries Limited (Subaru Corp.), Dr Ing hc F Porsche AG (Volkswagen AG)
• Original Assignee: McLaughlin Electronics Incorporated
• Inventors: Handfield, Michael, Laliberte, Helene
• Primary Examiner(s): Dombroske, George M.
• Application Number:
  US08/642,156
• Time in Patent Office: 691 Days
• Field of Search: 73/146.5, 73/700, 73/714, 73/723, 73/728, 73/733, 73/753, 73/754, 73/755, 73/756, 73/146.3, 73/146.8
• US Class Current: 73/146.5
• CPC Class Codes: B60C 23/0401 characterised by the type of alarm
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0433 Radio signals
• CPC Class Codes: B60C 23/0494 Valve stem attachments positioned inside the tyre chamber
• CPC Class Codes: B60C 23/0496 Valve stem attachments positioned outside of the tyre chamber
• CPC Class Codes: G06K 19/07764 the adhering arrangement making the record carrier attachable to a tire tire temperature or pressur control arrangements, see B60C23/00
• CPC Class Codes: H01Q 1/2241 used in or for vehicle tyres

Abstract

A pneumatic tire monitoring system is disclosed which provides a pressure sensor/transponder unit for each pneumatic tire of a vehicle to monitor tire pressure. A coded signal transmitted from each transponder unit is received by a multi-purpose receiver which may provide information to the vehicle operator or to other vehicle systems and subsystems. Each transponder unit is characterized by ultra low power consumption to extend the useful battery life. The transponder units may be mounted within the vehicle tires, or externally mounted. Impedance matching circuitry allows the use of the wheel rims with the transmitting antenna so as to avoid doppler shift induced by the rotating antenna and frequency drift induced by capacitive coupling.

Claims

1. Apparatus for monitoring inflation pressure of a pneumatic tire mounted on a conductive wheel, the apparatus comprising:

a cylindraceous housing having a passage to allow air ingress and egress to and from the pneumatic tire, the housing including an elongate portion adapted for extension through an aperture of the wheel, the housing also including a conductive portion, the elongate portion being sized to allow the conductive portion of the housing to contact the conductive wheel to allow transmission of the signal using the conductive wheel;

a pressure transducer disposed within the housing in fluid communication with the pneumatic tire for providing a signal indicative of the inflation pressure;

an electronic circuit for monitoring the signal and conditioning the signal for transmission to a remote receiver; and

a needle and spring disposed within one end of the elongate portion to selectively control inflation or deflation of the pneumatic tire.

2. The apparatus of claim 1 wherein the one end of the elongate portion is adapted for threaded engagement with a valve cap.

3. The apparatus of claim 1 further comprising a retaining member engageable with the elongate portion of the housing to secure the housing to the wheel.

4. The apparatus of claim 1 further comprising at least one conductive elastomeric seal surrounding a region of the elongate portion of the housing, the seal for contacting the conductive portion of the housing and the conductive wheel to provide an electrical path therebetween, the conductive elastomeric seal being sized to prevent air within the tire from escaping around the housing and through the aperture.

5. The apparatus of claim 4 further comprising a retaining member engageable with the elongate portion of the housing to secure the housing to the wheel.

6. The apparatus of claim 4 wherein the one end of the elongate portion is adapted for threaded engagement with a valve cap.

7. Apparatus for monitoring inflation pressure of a pneumatic tire mounted on a conductive wheel, the apparatus comprising:

a cylindraceous housing having a passage to allow air ingress and egress to and from the pneumatic tire, the housing including an elongate portion adapted for extension through an aperture of the wheel, the housing also including a conductive portion, the elongate portion being sized to allow the conductive portion of the housing to contact the conductive wheel to allow transmission of the signal using the conductive wheel;

a pressure transducer disposed within the housing in fluid communication with the pneumatic tire for providing a signal indicative of the inflation pressure;

an electronic circuit for monitoring the signal and conditioning the signal for transmission to a remote receiver;

at least one conductive elastomeric seal surrounding a region of the elongate portion of the housing, the seal for contacting the conductive portion of the housing and the conductive wheel to provide an electrical path therebetween, the conductive elastomeric seal being sized to prevent air within the tire from escaping around the housing and through the aperture; and

a needle and spring disposed within one end of the elongate portion to selectively control inflation or deflation of the pneumatic tire.

8. The apparatus of claim 7 wherein the one end of the elongate portion is adapted for threaded engagement with a valve cap.

9. The apparatus of claim 7 further comprising a retaining member engageable with the elongate portion of the housing to secure the housing to the wheel.

10. Apparatus for monitoring inflation pressure of a pneumatic tire mounted on a conductive wheel, the apparatus comprising:

a cylindraceous housing having a passage to allow air ingress and egress to and from the pneumatic tire, the housing including an elongate portion adapted for extension through an aperture of the wheel for threaded engagement with a valve cap, the housing also including a conductive portion, the elongate portion being sized to allow the conductive portion of the housing to contact the conductive wheel to allow transmission of the signal using the conductive wheel as an antenna;

a pressure transducer disposed within the housing in fluid communication with the pneumatic tire for providing a signal indicative of the inflation pressure;

an electronic circuit for monitoring the signal and conditioning the signal for transmission to a remote receiver;

at least one conductive elastomeric seal surrounding a region of the elongate portion of the housing, the seal for contacting the conductive portion of the housing and the conductive wheel to provide an electrical path therebetween, the conductive elastomeric seal being sized to prevent air within the tire from escaping around the housing and through the aperture;

a needle and spring disposed within one end of the elongate portion to selectively control inflation or deflation of the pneumatic tire; and

a retaining member engageable with the elongate portion of the housing to secure the housing to the wheel.