Method and apparatus for estimating contact patch shape of tire
First Claim
1. A method for estimating the contact patch shape of a tire, comprising the steps of:
- detecting vibrations of the tire which has a circumferential row of recesses in the tire tread arranged at the same pitch as a predetermined contact patch length;
extracting rotational order components corresponding to the pitch from the vibrations of the tire; and
estimating the contact patch shape of the tire from the magnitude of the rotational order components.
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Accused Products
Abstract
A simple method and apparatus for accurately estimating the contact patch shape of a moving tire. The vibration waveforms of a tire (20) with sipe rows (25A, 25B) formed at the respective pitches (Pa, Pb) in the left and right shoulder lands (24a, 24b) are detected by an acceleration sensor attached to a knuckle of the vehicle. Rotational order spectrums are obtained by performing a rotational order analysis on the vibration waveforms. The peak height (Za) of the rotational order (na) corresponding to the pitch (Pa) and the peak height (Zb) of the rotational order (nb) corresponding to the pitch (Pb) are extracted from the rotational order spectrums. The peak height (Za) is compared with the threshold value (Ka) to estimate whether the contact patch shape of the tire is longer than the contact patch length (La) of the tire contact patch shape (Fa) set as the use limit due to internal pressure drop or load increase, and the peak height (Zb) is compared with the threshold value (Kb) to estimate whether it is shorter than the contact patch length (Lb) of the tire contact patch shape (Fb) set as the use limit due to internal pressure rise or load decrease.
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Citations
13 Claims
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1. A method for estimating the contact patch shape of a tire, comprising the steps of:
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detecting vibrations of the tire which has a circumferential row of recesses in the tire tread arranged at the same pitch as a predetermined contact patch length; extracting rotational order components corresponding to the pitch from the vibrations of the tire; and estimating the contact patch shape of the tire from the magnitude of the rotational order components. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for estimating the contact patch shape of a tire which has a circumferential row of recesses in the tire tread arranged at the same pitch as a predetermined contact patch length, the apparatus comprising:
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a vibration detecting means installed on an unsprung portion of the vehicle for detecting the vibrations of the tire being transmitted thereto; a rotational order component extracting means for extracting rotational order components corresponding to the pitch from the vibrations of the tire; and a contact patch shape estimating means for estimating the contact patch shape of the tire based on the amplitude of the rotational order components. - View Dependent Claims (11)
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12. A method for estimating the contact patch shape of a tire, comprising the steps of:
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detecting vibrations of the tire which has a plurality of recess pairs in the tire tread, each pair composed of two recesses at the same interval as a predetermined contact patch length, the recess pairs arranged at a regular pitch along the tire circumference; extracting rotational order components corresponding to the pitch of the recess pairs from the vibrations of the tire; and estimating the contact patch shape of the tire from the amplitude of the rotational order components.
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13. A method for estimating the contact patch shape of a tire, comprising the steps of:
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detecting vibrations of the tire which has recesses circumferentially arranged in the same positions as predetermined edges of a contact patch in the tire tread at a regular pitch along the tire circumference; extracting rotational order components corresponding to the pitch of the recesses from the vibrations of the tire; and estimating the contact patch shape of the tire from the amplitude of the rotational order components.
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Specification