Tire Tread Pattern Beat Noise Suppression
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Solution Overview
Problem
Existing tire designs that reduce pitch noise are prone to generating beat noise during running, which affects the overall noise experience.
Innovation Solution
A tire tread pattern with tread design units of varying circumferential lengths, arranged in a specific sequence and interval ratios, where the amplitudes of Fourier-transformed pulse trains are limited to specific values to prevent excessive noise peaks and beat sound generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If tread design units are arranged with variable pitches to reduce pitch noise, then pitch noise is reduced, but beat noise occurs during running
Solution Approach 1:
The invention changes the parameters of the tread pattern by arranging tread design units with variable circumferential lengths (m=2,3,4, or 5 different lengths) and controlling the distribution of their circumferential positions. This parameter variation in the spatial arrangement modifies the noise characteristics to suppress both pitch noise and beat noise simultaneously.
Solution Approach 2:
The invention applies asymmetry by arranging tread design units with different circumferential lengths in a non-uniform pattern around the tire circumference. The asymmetric distribution of pulse amplitudes (corresponding to different tread unit lengths) and their circumferential positions creates a tread pattern that disrupts regular noise patterns while avoiding beat noise generation.
2Device complexity
If tread design units are arranged at the same pitches, then the tread pattern is simple, but unpleasant pitch noise occurs
Solution Approach 1:
The invention modifies the parameter of circumferential length of tread design units, using m=2,3,4, or 5 different lengths arranged in a specific variable pattern. This parameter change eliminates pitch noise while maintaining reasonable tread pattern complexity through systematic arrangement rather than random design.
3Object-affected harmful factors
If the number of different circumferential lengths increases, then pitch noise reduction improves, but the complexity of amplitude control increases
Solution Approach 1:
The invention systematically varies the circumferential lengths of tread design units (m=2,3,4, or 5 different lengths) and controls their circumferential positions to satisfy specific amplitude conditions in the Fourier transform. This parameter control approach achieves effective pitch noise reduction while managing complexity through defined mathematical relationships rather than arbitrary design.
Data Source
Figure 1
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AI summary
A tire (1) is provided with a tread pattern (2) comprising a series of a number N of tread design units (4) arranged repeatedly and circumferentially of the tire in a sequence and having a number m of different circumferential lengths (L). A first pulse train (11) is defined by viewing the tread design units as pulses 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 the number m of different circumferential lengths. A maximum value Pmax of amplitudes P(k) (k = order from 1 to 2N) of frequencies obtained by Fourier transforming the first pulse train is limited to specific values. The amplitudes P(k) and P(k+1) of every two of the adjacent orders (k) and (k+1) do not satisfy a condition that both of the amplitudes P(k) and P(k+1) have values of 2/3 or more times the maximum value Pmax.