Claims
- 1. A tire air pressure detecting device comprising:
- output means installed on a vehicle, for outputting a signal including a vibration frequency component of a tire while said vehicle is moving;
- deriving means for deriving gains in regard to each frequency of said vibration frequency component;
- extracting means for extracting a plurality of said gains which correspond to a predetermined frequency band;
- estimation means for estimating a resonance frequency at which a peak gain exists, based on a distribution of said plurality of gains; and
- detecting means for detecting a tire air pressure condition based on said resonance frequency having said peak gain.
- 2. A tire air pressure detecting device as set forth in claim 1, wherein said estimation means includes:
- threshold setting means for setting a threshold value from said peak gain of said plurality of gains, said threshold value being lower than said peak gain; and
- deriving means for deriving two frequencies at which two gains among said plurality of gains attain said threshold value, and for designating an intermediate value between said two frequencies as said resonance frequency.
- 3. A tire air pressure detecting device as set forth in claim 1, wherein said estimation means includes:
- summing means for summing values of gains within said predetermined frequency band; and
- deriving means for deriving said resonance frequency from a frequency corresponding to a center of gravity point of said values of gains summed by said summing means.
- 4. A tire air pressure detecting device as set forth in claim 1, wherein said output means comprises a wheel speed sensor for generating a signal corresponding to a rotation speed of a wheel of said tire.
- 5. A tire air pressure detecting device as set forth in claim 1, wherein said estimation means estimates said resonance frequency based on vibrations of an unsprung mass of said vehicle, said vibrations being generated in at least one of a vertical direction and a longitudinal direction relative to said vehicle.
- 6. A tire air pressure detecting device as set forth in claim 1, wherein said detecting means preliminarily stores a resonance frequency value as a reference value, and detects lowering of a tire pressure condition from comparing said resonance frequency estimated by said estimation means with said reference value, where said reference value corresponds to a normal condition of said tire air pressure condition.
- 7. A tire air pressure detecting device comprising:
- output means installed on a vehicle, for outputting a signal including a vibration frequency component of a tire while said vehicle is moving;
- analyzing means for analyzing a distribution of gains in regard to each frequency of said vibration frequency component;
- determining means for determining a frequency at which a peak gain among said distribution of gains exists, based on said distribution of gains; and
- detecting means for detecting a tire air pressure condition based on said frequency having said peak gain.
Priority Claims (12)
Number |
Date |
Country |
Kind |
3-294622 |
Nov 1991 |
JPX |
|
4-18983 |
Feb 1992 |
JPX |
|
4-57521 |
Feb 1992 |
JPX |
|
4-55942 |
Mar 1992 |
JPX |
|
4-125623 |
Apr 1992 |
JPX |
|
4-125624 |
Apr 1992 |
JPX |
|
4-128078 |
Apr 1992 |
JPX |
|
4-128079 |
Apr 1992 |
JPX |
|
4-164186 |
May 1992 |
JPX |
|
4-297969 |
Oct 1992 |
JPX |
|
4-297843 |
Oct 1992 |
JPX |
|
4-338649 |
Dec 1992 |
JPX |
|
Parent Case Info
This is a continuation-in-part application of application Ser. No. 08/133,440 filed Oct. 8, 1993, which is a continuation-in-part application of application Ser. No. 08/387,703 filed Jul. 9, 1993, now abandoned, which in turn is based on PCT application PCT/JP92/01457 filed Nov. 10, 1992.
US Referenced Citations (5)
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EPX |
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DEX |
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DEX |
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Jun 1984 |
JPX |
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Jun 1987 |
JPX |
62-149503 |
Jul 1987 |
JPX |
62-149502 |
Jul 1987 |
JPX |
63-138229 |
Jun 1988 |
JPX |
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Dec 1988 |
JPX |
2-96613 |
Apr 1990 |
JPX |
8803878 |
Jun 1988 |
WOX |
9114586 |
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WOX |
Non-Patent Literature Citations (3)
Entry |
Patent Abstract of Japan, vol. 11, No. 380, Dec. 11, 1987. |
Patent Abstract of Japan, vol. 10 No. 41, Feb. 18, 1986. |
Patent Abstract of Japan, vol. 12 No. 227, Jun. 28, 1998. |
Continuation in Parts (2)
|
Number |
Date |
Country |
Parent |
133440 |
Oct 1993 |
|
Parent |
87703 |
Jul 1993 |
|