METHOD OF CALCULATING DEFLECTION OF ROTATING TIRE, METHOD OF ACCUMULATING DATA OF ROTATING TIRE, METHOD OF CALCULATING CONTACT LENGTH OF ROTATING TIRE

• US 20090118891A1
• Filed: 04/20/2007
• Published: 05/07/2009
• Est. Priority Date: 04/21/2006
• Status: Active Grant

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Miyashita, Naoshi, Matsuda, Jun, Kitazaki, Tsuyoshi, Koguchi, Noritaka
• Granted Patent: US 8,437,905 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: B60C 23/064 comprising tyre mounted deformation sensors, e.g. to determine road contact area
• CPC Class Codes: G01B 21/32 for measuring the deformation in a solid
• CPC Class Codes: G01M 17/02 Tyres

Abstract

A method of calculating deflection of a rotating tire, through high speed data processing, based on measurement time series data of acceleration on a tire tread portion has the following steps. A step of acquiring measurement time series data of acceleration on a tire circumference in a radial direction of a rotating tire; a step of extracting acceleration data in a vicinity of a contact region from the acquired measurement data and subjecting the extracted acceleration data to least-square regression using a second-order differential function expression of a deflection function expression that represents a peak shape having a peak value and a curve gradually approaching to zero on both sides thereof, whereby a deflection function parameter values are determined; and a step of calculating a contact deflection from the deflection function expression determined by the deflection function parameter values.

Claims

1. A method of calculating deflection of a rotating tire that calculates a distribution of deflections at a tire tread portion in a radial direction of the tire when the tire is rotating on a road surface, the method comprising:

an acquiring step of acquiring measurement time series data of acceleration on a tire circumference in a radial direction of a rotating tire;

a least-square regression step of determining deflection function parameter values in such a manner that acceleration data in a vicinity of a contact region of the tire is extracted from the acquired measurement time series data of acceleration on the tire circumference, and the extracted acceleration data is subjected to least-square regression using a second-order differential function expression of a deflection function expression that represents a peak shape having a peak value and a curve which is gradually approaching to zero on both sides of the peak shape; and

a calculation step of calculating a distribution of deflection of a tire during rotation from the deflection function expression determined by the deflection function parameter values.

2. The method of calculating deflection of a rotating tire according to claim 1, wherein the deflection function expression that represents the peak shape is an asymmetrical Gaussian type function expression having a curve representing an asymmetrical shape on both sides of a peak, in accordance with the parameter values.

3. The method of calculating deflection of a rotating tire according to claim 1, wherein the deflection function expression is any one of formulas (1-1), (1-2), (1-3), (1-4) and (1-5) below:

[FORMULA 1]

4. The method of calculating deflection of a rotating tire according to claim 1, wherein the measurement time series data of acceleration in the radial direction is data acquired by an acceleration sensor mounted on the tire tread portion, the acceleration sensor being adapted for measuring acceleration in the radial direction.

5. The method of calculating deflection of a rotating tire according to claim 4, wherein the acceleration sensor is mounted at a center in a width direction of the tire tread portion, on a liner portion, on an outer periphery of a belt ply, or inside a cap tread.

6. The method of calculating deflection of a rotating tire according to claim 4, wherein as the acceleration sensor, a plurality of acceleration sensors are mounted on the tire tread portion in the width direction, and measurement time series data of acceleration in the radial direction is obtained from each of the plurality of acceleration sensors.

7. The method of calculating deflection of a rotating tire according to claim 5, wherein as the acceleration sensor, a plurality of acceleration sensors are mounted on the tire tread portion in the width direction, and measurement time series data of acceleration in the radial direction is obtained from each of the plurality of acceleration sensors.

8. A method of accumulating data of a rotating tire, comprising:

an acquiring step of acquiring measurement time series data of acceleration on a tire circumference in a radial direction of a rotating tire;

a least-square regression step for determining deflection function parameter values in such a manner that acceleration data in a vicinity of a contact region of the tire is extracted from the acquired measurement time series data of acceleration on the tire circumference, and the extracted acceleration data is subjected to least-square regression using a second-order differential function expression of a deflection function expression that represents a peak shape having a peak value and a curve which is gradually approaching to zero on both sides of the peak shape; and

an accumulating step of accumulating the deflection function parameter values determined in the least-square regression step as data at every round of tire rotation.

9. A method of calculating a contact length of a rotating tire, comprising:

an acquiring step of acquiring measurement time series data of acceleration on a tire circumference in a radial direction of a rotating tire;

a least-square regression step of determining deflection function parameter values in such a manner that acceleration data in a vicinity of a contact region of the tire is extracted from the acquired measurement time series data of acceleration on the tire circumference, and the extracted acceleration data is subjected to least-square regression using a second-order differential function expression of a deflection function expression that represents a peak shape having an peak value and a curve which is gradually approaching to zero on both sides of the peak shape;

a calculation step of calculating a deflection in a vicinity of the contact region from the deflection function expression determined by using the deflection function parameter values; and

a contact length calculating step for calculating a contact length of the rotating tire based on the deflection of the tire which is calculated in the calculation step.

10. The method of calculating a contact length of a rotating tire according to claim 9, includes:

determining, in a tire rotation orbit represented by the curve of the deflection function expression that is determined by the deflection function parameter values, intersections between a horizontal line touching to a lowest point of the tire rotation orbit and an arcuate shaped rotation orbit representing zero deflection as A, B;

determining a center of tire rotation as O;

determining points on the horizontal line as point C and point D, provided that an angle ∠

COD which is created by the points C and D, and the center of tire rotation O has a certain angle from 50 to 95% of an angle ∠

AOB which is created by the intersections A, B and the center of tire rotation O; and

determining the length between the point C and the point D as the contact length of the rotating tire.