Tire Tread Pattern Beat Noise Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tire designs that reduce pitch noise are prone to generating beat noise during running, which is unpleasant and difficult to mitigate effectively.
Innovation Solution
A tire tread pattern with tread design units of varying circumferential lengths, where the pulses are arranged at intervals proportional to these lengths, and their magnitudes are expressed relative to a median value, with specific constraints on amplitude F(k) to limit maximum amplitude and adjacent order amplitudes, preventing excessive beat sound generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the tread design units are arranged with variable pitches to reduce pitch noise, then the pitch noise is reduced, but beat noise occurs during running
Solution Approach 1:
The invention changes the parameters of the tread design units by varying both the circumferential lengths and the arrangement pitches of the tread design units. Specifically, the tread design units have at least two different circumferential lengths, and their pitches are varied according to specific mathematical relationships (equations 1-3) to control the frequency spectrum of generated noise. This parameter variation prevents the formation of beat noise while maintaining pitch noise reduction.
Solution Approach 2:
The invention introduces asymmetry in the tread pattern design by using tread design units with different circumferential lengths arranged at non-uniform pitches. The asymmetric arrangement prevents periodic repetition that causes beat noise, while the controlled asymmetry through specific pitch relationships maintains pitch noise reduction. The tread design units are not uniformly distributed but follow a controlled asymmetric pattern defined by the patent's mathematical equations.
2Ease of manufacture
If the pattern units are repeated at the same pitches, then the tread pattern is simple to manufacture, but unpleasant pitch noise occurs
Solution Approach 1:
The invention varies the pitches of the tread design units according to specific mathematical relationships (equations 1-3) to control the frequency spectrum of generated noise. By changing the pitch parameters in a controlled manner rather than using uniform repetition, the patent reduces pitch noise while maintaining manufacturability through systematic design rules.
Solution Approach 2:
The invention uses periodic variation in the pitch of tread design units to control noise characteristics. The pitches are varied periodically according to specific mathematical relationships, creating a controlled periodic pattern that reduces pitch noise through frequency distribution control while maintaining manufacturing feasibility through systematic repetition of the variable pitch pattern.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
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.