Capacitive pressure sensor
First Claim
Patent Images
1. A wheel, comprising:
- a rim;
a tire surrounding said rim and sealing a gas under pressure within a cavity formed by said tire and said rim; and
a pressure sensor in said tire, wherein the pressure sensor is configured to sense the pressure of the gas within the cavity, said pressure sensor comprising;
a first conductive layer;
a compressible dielectric contiguous to said first conductive layer; and
a second conductive layer contiguous to said compressible dielectric, wherein said first and second conductive layers form a capacitor;
wherein said capacitor is adapted to reflect a capacitance in relation to pressure changes within the cavity; and
wherein said pressure sensor further comprises a temperature compensating element associated with said capacitor.
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Abstract
A capacitive pressure sensor comprises a pair of conductive plates surrounding a compressible dielectric to form a capacitor. Changes in pressure create changes in the capacitance of the capacitor which in turn may be measured to determine the changes in pressure. The pressure sensor may be constructed to be temperature and centripetal force compensated so that it may be positioned in a tire. A further embodiment uses the conductive plates to form a radiating element for the sensor such that it may wirelessly communicate with a remote interrogator.
31 Citations
67 Claims
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1. A wheel, comprising:
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a rim; a tire surrounding said rim and sealing a gas under pressure within a cavity formed by said tire and said rim; and a pressure sensor in said tire, wherein the pressure sensor is configured to sense the pressure of the gas within the cavity, said pressure sensor comprising; a first conductive layer; a compressible dielectric contiguous to said first conductive layer; and a second conductive layer contiguous to said compressible dielectric, wherein said first and second conductive layers form a capacitor; wherein said capacitor is adapted to reflect a capacitance in relation to pressure changes within the cavity; and wherein said pressure sensor further comprises a temperature compensating element associated with said capacitor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A pressure sensing system, comprising:
a vehicle, comprising; a control system; and a wheel, comprising; a rim; a tire surrounding said rim and sealing a gas under pressure within a cavity formed by said tire and said rim; a pressure sensor in said tire, wherein the pressure sensor is configured to sense pressure within said tire, said pressure sensor including a first conductive layer;
a compressible dielectric contiguous to said first conductive layer; and
a second conductive layer contiguous to said compressible dielectric, wherein said first and second conductive layers form said capacitor, said capacitor having a capacitance that varies according to pressure changes within the cavity and further includes a temperature compensation element; anda remote communication device associated with said pressure sensor, wherein said remote communication device is configured to communicate information from said pressure sensor to a remote location. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method of sensing pressure of a gas in a cavity, comprising:
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forming a capacitor in the cavity from a compressible dielectric material and a pair of conductive layers; measuring capacitance associated with the capacitor, wherein changes in capacitance are related to changes in pressure as a function of the compressible dielectric; and compensating for temperature changes. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A method of sensing pressure in a tire, comprising:
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forming a pressure sensor from a compressible material and a pair of conductive layers; associating a remote communication device with the pressure sensor; placing the pressure sensor in a tire; determining pressure changes by changes in the compressible material which affect the capacitance of the pressure sensor; compensating for temperature changes within the tire; and interrogating the remote communication device to convey information about pressure changes in the tire. - View Dependent Claims (41, 42, 43, 44)
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45. A wheel, comprising:
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a rim; a tire surrounding said rim and sealing a gas under pressure within a cavity formed by said tire and said rim; and a pressure sensor configured to sense the pressure of the gas within the cavity, said pressure sensor comprising; a first conductive layer; a compressible dielectric contiguous to said first conductive layer; and a second conductive layer contiguous to said compressible dielectric, wherein said first and second conductive layers form a capacitor; wherein said capacitor is adapted to reflect a capacitance in relation to pressure changes within the cavity; and wherein said pressure sensor further comprises a rotational force compensator. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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57. A pressure sensor for sensing pressure of a gas in a cavity, comprising:
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a first conductive layer; a second conductive layer; a compressible dielectric material disposed between the first and second conductive layers to form a capacitor in the cavity having a capacitance, wherein the capacitor is configured to change capacitance in relation to pressure changes on the compressible dielectric and thereby reflect pressure information; and a temperature compensating element configured to compensate the pressure information for temperature changes. - View Dependent Claims (58, 59, 60, 61, 62, 63, 64, 65, 66, 67)
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Specification