Tire pneumatic pressure detector
First Claim
1. A tire pneumatic pressure detector comprising:
- cruising signal generation means for generating a cruising signal during cruising of a vehicle, said cruising signal including vibration frequency components of a tire installed on said vehicle;
extraction means for extracting an extracted characteristic from said cruising signal, said extracted characteristic being one of a resonance frequency of said tire and a spring constant of said tire;
tire pneumatic pressure prediction means for predicting tire pneumatic pressure based on said extracted characteristic;
signal generation means for generating predetermined signals when said tire is replaced with a tire having a predetermined pneumatic pressure;
memory means for storing, for a plurality of vehicle types, data representative of a substantially linear relationship of a change in said extracted characteristic with a change in said tire pneumatic pressure;
computation means for, responsive to said predetermined signal, computing a critical characteristic corresponding to a critical pneumatic pressure of a presently installed tire based on said relationship stored in said memory means and said extracted characteristic, said critical characteristic being one of a critical resonance frequency and a critical spring constant; and
determination means for determining tire pneumatic pressure based on said critical characteristic.
1 Assignment
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Accused Products
Abstract
Pickup coils which generate vehicle wheel speed signals which include vibration frequency components of tires during vehicle cruising are provided. An electronic control unit extracts resonance frequencies of tires from the vehicle wheel speed signals and estimates tire pneumatic pressure based on the extracted resonance frequencies. When an estimated vehicle wheel pneumatic pressure falls below a predetermined critical pneumatic pressure, pneumatic pressure decline warnings are generated and displayed by a display unit. An update switch is provided and when this update switch is turned on when replacing tires, the electronic control unit adjusts and sets the value of the critical pneumatic pressure described above based on the resonance frequency extracted during this time.
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Citations
27 Claims
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1. A tire pneumatic pressure detector comprising:
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cruising signal generation means for generating a cruising signal during cruising of a vehicle, said cruising signal including vibration frequency components of a tire installed on said vehicle; extraction means for extracting an extracted characteristic from said cruising signal, said extracted characteristic being one of a resonance frequency of said tire and a spring constant of said tire; tire pneumatic pressure prediction means for predicting tire pneumatic pressure based on said extracted characteristic; signal generation means for generating predetermined signals when said tire is replaced with a tire having a predetermined pneumatic pressure; memory means for storing, for a plurality of vehicle types, data representative of a substantially linear relationship of a change in said extracted characteristic with a change in said tire pneumatic pressure; computation means for, responsive to said predetermined signal, computing a critical characteristic corresponding to a critical pneumatic pressure of a presently installed tire based on said relationship stored in said memory means and said extracted characteristic, said critical characteristic being one of a critical resonance frequency and a critical spring constant; and determination means for determining tire pneumatic pressure based on said critical characteristic.
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2. A tire pneumatic pressure detector comprising:
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cruising signal generation means for generating a cruising signal during cruising of a vehicle, said cruising signal including vibration frequency components of a tire installed on said vehicle; extraction means for extracting an extracted characteristic of said tire from said cruising signal, said extracted characteristic being one of a resonance frequency of said tire and a spring constant of said tire; memory means for storing a critical characteristic corresponding to a critical pneumatic pressure which is a standard for determining abnormal tire pneumatic pressure in a predetermined standard vehicle tire, and for storing a standard characteristic indicative of when said standard vehicle tire has a predetermined pneumatic pressure, said critical characteristic being one of a critical resonance frequency and a critical spring constant and said standard characteristic being one of a standard resonance frequency and a standard spring constant; signal generation means for generating a predetermined signal when said standard vehicle tire is replaced with a vehicle tire having said predetermined pneumatic pressure; computation means for, responsive to said predetermined signal, computing a deviation between said standard characteristic and said extracted characteristic; and alteration means for altering said critical characteristic based on said deviation; tire pneumatic pressure prediction means for predicting tire pneumatic pressure based on said extracted characteristic. - View Dependent Claims (3, 4, 5, 6)
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7. A tire pneumatic pressure detector comprising:
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cruising signal generation means for generating a cruising signal during cruising of a vehicle, said cruising signal including vibration frequency components of a tire installed on said vehicle; extraction means for extracting an extracted characteristic from said cruising signal, said extracted characteristic being one of a resonance frequency of said tire and a spring constant of said tire; tire pneumatic pressure prediction means for predicting tire pneumatic pressure based on said extracted characteristic; memory means for storing a standard characteristic of a predetermined standard tire indicative of when said tire has a predetermined pneumatic pressure, and for storing a critical characteristic corresponding to a critical tire pneumatic pressure which is a standard for determining an abnormality in a pneumatic pressure of said standard tire, said standard characteristic being one of a standard resonance frequency of said standard tire and a standard spring constant of said tire and said critical characteristic being one of a resonance frequency and a critical spring constant; first determination means for determining an abnormality in tire pneumatic pressure of said standard tire based on said extracted characteristic and said critical characteristic stored in said memory means; signal generation means for generating a predetermined signal when said standard tire is replaced with a tire having said predetermined pneumatic pressure; computation means for computing, responsive to said predetermined signal, a relationship between said standard characteristic and said extracted characteristic; alteration means for altering said critical characteristic based on said relationship; and second determination means for determining an abnormality in tire pneumatic pressure based on said extracted characteristic and said critical characteristic altered by said alteration means. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A tire pneumatic pressure detector comprising:
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cruising signal generation means for generating a cruising signal during cruising of a vehicle, said cruising signal including vibration frequency components of a tire installed on said vehicle; extraction means for extracting an extracted characteristic from said cruising signal, said extracted characteristic being one of a resonance frequency of said tire and a tire spring constant of said tire; tire pneumatic pressure prediction means for predicting tire pneumatic pressure based on said extracted characteristic; memory means for storing a standard characteristic when said tire has a predetermined pneumatic pressure and for storing a critical characteristic corresponding to a critical tire pneumatic pressure which is a standard for determining abnormality in said pneumatic pressure of said standard tire, said standard characteristic being a one of a standard tire resonance frequency of said standard tire and a standard spring constant of said standard tire and said critical characteristic being one of a critical resonance frequency and a critical spring constant; first determination means for determining an abnormality in tire pneumatic pressure of said standard tire based on said extracted characteristic and said standard characteristic stored in said memory means; signal generation means for generating a predetermined signal when said standard tire is replaced with a tire having said predetermined pneumatic pressure; computation means for, responsive to said predetermined signal, computing a relationship of a change in said extracted characteristic with standard tire pneumatic pressure as a slope based on said standard characteristic and said critical characteristic stored in said memory means responsive to said predetermined signal; alteration means for computing a critical characteristic corresponding to a critical pneumatic pressure of a tire after replacement based on said slope computed by said computation means and said extracted characteristic after tire replacement; and second determination means for determining an abnormality in said tire pneumatic pressure based on said extracted characteristic and said critical characteristic altered by said alteration means.
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18. A tire pneumatic pressure detector comprising:
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cruising signal generation means which generates a cruising signal during cruising of a vehicle, said cruising signal including vibration frequency components of tires installed on said vehicle; extraction means for extracting an extracted characteristic from said cruising signal, said extracted characteristic being one of a resonance frequency of said tire and a tire spring constant of said tire; tire pneumatic pressure prediction means for predicting tire pneumatic pressure based on said extracted characteristic; memory means for storing, for plurality of vehicle types, a slope indicative of a change in said extracted characteristic with tire pneumatic pressure; signal generation means for generating a predetermined signal when said tire is replaced with a tire having a predetermined pneumatic pressure; computation means for computing a critical characteristic for a critical pneumatic pressure of a presently installed tire based on said slope stored in said memory means and said extracted characteristic responsive to said predetermined signal, said critical characteristic being one of a critical resonance frequency and a critical spring constant; and determination means for determining tire pneumatic pressure based on said critical characteristic computed by said computation means. - View Dependent Claims (19)
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20. A tire pneumatic pressure detector comprising:
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cruising signal generation means for generating a cruising signal during cruising of a vehicle, said cruising signal including vibration frequency components of a tire installed on said vehicle; extraction means for extracting an extracted characteristic from said cruising signal, said extracted characteristic being one of a resonance frequency of said tire and a spring constant of said tire; tire pneumatic pressure prediction means for predicting tire pneumatic pressure based on said extracted characteristic; memory means for storing a standard characteristic of a predetermined standard tire indicative of when said tire has a predetermined pneumatic pressure and for storing a substantially linear slope indicative of a change in said standard characteristic with said pneumatic pressure of said standard tire, said standard characteristic being one of a standard resonance frequency of said standard tire and a standard spring constant of said standard tire; first critical pneumatic pressure computation means for computing a critical characteristic corresponding to a critical pneumatic pressure of said standard tire based on said slope stored by said memory means, said critical characteristic being one of a critical resonance frequency and a critical spring constant; first determination means for determining an abnormality in said tire pneumatic pressure based on said extracted characteristic and said critical characteristic; signal generation means for generating a predetermined signal when said standard tire is replaced with a tire having said predetermined pneumatic pressure; deviation computation means for, responsive to said predetermined signal, computing a deviation between said standard characteristic and said extracted characteristic; alteration means for altering said critical characteristic based on said slope stored in said memory means; second determination means for determining an abnormality in tire pneumatic pressure based on said extracted characteristic and said critical characteristic altered by said alteration means after said deviation computation means detects said predetermined signal; conformity determination means for determining whether said deviation is within said predetermined range; and prohibition means for prohibiting said alteration means from altering said critical characteristic after said conformity determination means determines that said deviation is not within said predetermined range. - View Dependent Claims (21)
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22. A tire pneumatic pressure detector comprising:
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cruising signal generation means for generating a cruising signal including vibration frequency components of a tire installed on a vehicle; extraction means for extracting an extracted characteristic of said tire from said cruising signal, said extracted characteristic being one of a resonance frequency of said tire and a spring constant of said tire; memory means for storing a critical characteristic corresponding to a critical pneumatic pressure which is a standard for determining pneumatic pressure abnormality in a predetermined standard tire, and a standard characteristic, said critical characteristic being one of a critical resonance frequency and a critical spring constant and said standard characteristic being one of a standard resonance frequency and standard spring constant extracted from said cruising signal when said standard tire has a predetermined pneumatic pressure; signal generation means for generating a predetermined signal when said standard tire is replaced with a tire having said predetermined pneumatic pressure; deviation computation means for computing a deviation between said standard characteristic and said extracted characteristic responsive to detection of said predetermined signal; and alteration means for altering said critical characteristic based on said deviation computed by said deviation computation means.
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23. A system for detecting a tire pressure, said system comprising:
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cruising signal generating means for generating an electrical cruising signal representative of movement of a vehicle on which said tire is installed; characteristic extracting means for generating an electrical characteristic signal representative of a parameter characteristic of a suspension of said vehicle extracted from said cruising signal; a memory storing data indicative of a relationship between said parameter and said tire pressure and generating electrical data signals representative of said data; tire replacement signalling means for generating an electrical tire change signal representative of a replacement of said tire on said vehicle; and pressure determining means for generating an electrical pressure signal representative of said tire pressure based on said characteristic signal, said data signals and said tire change signal. - View Dependent Claims (24, 25, 26, 27)
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Specification