Tire uniformity improvement through identification of a composite uniformity parameter using Weibull distributions
View Patent ↗Methods and systems for improving the uniformity of a tire are provided. More specifically, one or more characteristics of a composite uniformity parameter can be determined from harmonic magnitudes associated with a plurality of harmonics of the composite uniformity parameter. For instance, a range of a composite uniformity parameter and/or a distribution of amplitudes of a composite uniformity parameter for a set of tires can be determined from harmonic magnitudes associated with selected harmonics of the composite uniformity parameter. According to example aspects of the present disclosure, the one or more characteristics of the composite uniformity parameter can be determined using Weibull distributions of the harmonic magnitudes. Once identified, the one or more characteristics can be used to modify tire manufacture to improve tire uniformity.
1. A method of improving the uniformity of a tire, comprising:
obtaining, by one or more computing devices, uniformity data associated with a set of a plurality of tires, the uniformity data comprising one or more sets of harmonic magnitudes for one or more selected harmonics of a uniformity parameter for the set of tires;
identifying, by the one or more computing devices, one or more parameters of a Weibull distribution for each of the one or more sets of harmonic magnitudes;
identifying, by the one or more computing devices, one or more characteristics of the composite uniformity parameter for the set of tires based at least in part on the one or more parameters of the Weibull distribution for each of the one or more sets of harmonic magnitudes; and
modifying tire manufacture based at least in part on the one or more characteristics of the composite uniformity parameter.
2. The method of claim 1 , wherein the one or more characteristics of the composite uniformity parameter comprise a range associated with the composite uniformity parameter for the set of tires.
3. The method of claim 2 , wherein the range is estimated based at least in part on a scale parameter of a Weibull distribution associated with a set of harmonic magnitudes for a first harmonic of the uniformity parameter for the set of tires and a geometric progression parameter, the geometric progression parameter associated with the progression of scale parameters for Weibull distributions associated with a plurality of different harmonics of the uniformity parameter.
4. The method of claim 1 , wherein identifying, by the one or more computing devices, one or more characteristics of the composite uniformity parameter comprises
estimating, by the one or more computing devices, one or more parameters of a composite Weibull distribution for the set of tires based at least in part on the uniformity data; and
determining, by the one or more computing devices, the one or more characteristics of the composite uniformity parameter for the set of tires based at least in part on the composite Weibull distribution.
5. The method of claim 4 , wherein the uniformity data comprises a first set of harmonic magnitudes for a first selected harmonic of the uniformity parameter and a second set of harmonic magnitudes for a second selected harmonic of the uniformity parameter, the first set of harmonic magnitudes being associated with a first Weibull distribution and the second set of harmonic magnitude being associated with a second Weibull distribution.
6. The method of claim 5 , wherein the one or more parameters of the composite Weibull distribution are determined by summing the first Weibull distribution and the second Weibull distributions to generate a sum of Weibull distributions.
7. The method of claim 6 , wherein the one or more parameters of the composite Weibull distribution are identified by fitting the composite Weibull distribution to the sum of Weibull distributions.
8. The method of claim 4 , wherein the one or more characteristics of the composite uniformity parameter comprise a distribution of amplitudes of the composite uniformity parameter for the set of tires.
9. The method of claim 8 , wherein the distribution of amplitudes of the composite uniformity parameter is determined numerically using a distribution function based at least in part on the one or more parameters of the composite Weibull distribution.
10. The method of claim 1 , wherein modifying tire manufacture comprises sorting or grading tires based at least in part on the one or more characteristics of the composite uniformity parameter.
11. The method of claim 8 , wherein modifying tire manufacture comprises:
predicting a uniformity yield based at least in part on the distribution of amplitudes; and
modifying tire manufacture based at least in part on the uniformity yield.
12. The method of claim 11 , wherein modifying tire manufacture based at least in part on the uniformity yield comprises adjusting a sorting threshold for the uniformity parameter based at least in part on the uniformity yield.
13. The method of claim 1 , wherein modifying tire manufacture comprises rotating one or more tires relative to one or more process elements used in tire manufacture based at least in part on the one or more characteristics of the composite uniformity parameter.
14. The method of claim 1 , wherein the uniformity parameter comprises one or more of low and high speed radial force variation, tangential force variation, radial run out, lateral run out, mass variance, conicity, and ply steer.