US 2019/0168545 A1Published application

Tire

AssigneeSumitomo Rubber Industries, Ltd.

InventorsTatsuya SASAKI, Emi UEDA, Masatoshi TANAKA, Ken MIYAZAWA, Sawa OGIHARA, Ryuhei SANAE

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Abstract

A tire has a tread pattern comprising a series of a number N of tread design units arranged repeatedly and circumferentially of the tire in a sequence. The tread design units have at least two different circumferential lengths. Viewing the tread design units as pulses, a pulse train is defined. Magnitudes of the pulses are proportional to the circumferential lengths of the tread design units. The average of the magnitudes corresponding to the different circumferential lengths is limited to 1.00. Maximum value Fmax of amplitude F(k) of k-th order (k=1 to 2N) of frequencies obtained by Fourier transforming the pulse train is limited to be 4.52−0.0125 N. The amplitudes F(k) and F(k+1) of every two of the adjacent orders (k) and (k+1) are limited so as not to satisfy a condition that both of the amplitudes F(k) and F(k+1) are 2/3 or more times the Fmax.

A tire comprising:

a tread portion provided with a tread pattern,
the tread pattern comprising a series of a number N of tread design units arranged repeatedly and circumferentially of the tire in a sequence,
the tread design units having at least two different circumferential lengths, wherein when viewing the tread design units as the number N of pulses having magnitudes proportional to the respective circumferential lengths of the tread design units, and
defining a pulse train such that the number N of the pulses are arranged in the same sequence as the tread design units at intervals which are defined by the circumferential lengths of the corresponding tread design units expressed in term of a ratio to one of said at least two different circumferential lengths, and further
expressing magnitudes of the pulses by the respective circumferential lengths in term of a ratio to the median value of said at least two different circumferential lengths,
the average of the magnitudes of the pulses corresponding to said at least two different circumferential lengths is limited to 1.00,
a maximum value Fmax of amplitude F(k) of k-th order (k=1 to 2N) of frequencies obtained by Fourier transforming said pulse train with the following formula (1) is limited to satisfy the following condition:
Fmax<=4.52−0.0125 N,
F
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(
k
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=
10
k
2
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c
k
2
+
d
k
2
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c
k
=
∑
j
=
1
N
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p
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(
j
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·
sin
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(
2
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π
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k
l
·
X
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(
j
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d
k
=
∑
j
=
1
N
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p
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(
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·
cos
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(
2
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π
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k
l
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X
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(
j
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,
(
1
)
wherein
P(j) is the magnitude of the j-th pulse (j=1 to N) counted from a beginning of the pulse train,
X(j) is the position of the j-th pulse from the beginning of the pulse train, and
l is a circumference length parameter equal to the sum of said ratios expressing the circumferential lengths of all the tread design units in a series, and
the amplitudes F(k) of every two of the adjacent orders (k) and (k+1) are limited so as not to satisfy a condition that both of the amplitudes F(k) and F(k+1) have values of 2/3 or more times said maximum value Fmax.

103 more elements

Facts

Application

16/206,588Filed 30 Nov 2018

Priority

JP 2017-2319521 Dec 2017

Published

6 Jun 2019

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

B60C 11/0318
Tread patterns: irregular patterns with particular pitch sequence
B60C 11/0306
Tread patterns: patterns comprising block rows or discontinuous ribs
B60C 11/0332
Characterised by special properties of the tread pattern: by the footprint-ground contacting area of the tyre tread
B60C 11/11
Tread patterns: in which the raised area of the pattern consists only of isolated elements, e.g. blocks

Abstract

Claims20