Tire Sidewall Roughness Pattern for 3D Appearance at Reduced Gauge

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Solution Overview

Problem

Thinning the gauge thickness of tire side walls to reduce weight makes it difficult to maintain or improve the appearance of the side wall due to reduced unevenness.

Innovation Solution

A decorative region with large regions formed by combining small regions of varying arithmetic average roughness, creating a three-dimensional effect through triangular pyramids and boundary lines, is applied to the outer surface of the side wall portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the gauge thickness of the side wall portion is thinned down to reduce tire weight, then the weight of the tire is reduced, but the unevenness cannot be formed deeply and the appearance of the side wall portion deteriorates

Engineering Contradiction:
Improvetire weightVSAvoidappearance of side wall portion
Core Design Contradiction:
Weight of moving objectVSShape

Solution Approach 1:

The invention applies local quality by creating regions with different surface roughness characteristics on the side wall portion. Specifically, it forms a first region with a first arithmetic average roughness and a second region with a second arithmetic average roughness that is different from the first, allowing each region to contribute differently to the overall appearance while maintaining a thin gauge thickness. This local differentiation enables aesthetic enhancement without requiring increased material thickness.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention transitions from relying solely on depth (vertical dimension) to create unevenness to utilizing surface roughness (micro-scale surface dimension). By controlling the arithmetic average roughness of different regions rather than just the depth of grooves, the invention creates visual interest and perceived three-dimensionality through surface texture variations even when the overall gauge thickness is reduced.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Weight of moving object

If the gauge thickness of the side wall portion is thinned down to reduce tire weight, then the weight of the tire is reduced, but the three-dimensional feeling and appearance improvement become difficult to achieve

Engineering Contradiction:
Improvetire weightVSAvoidthree-dimensional feeling of side wall portion
Core Design Contradiction:
Weight of moving objectVSShape

Solution Approach 1:

The invention creates distinct regions with different roughness characteristics - a first region with a first arithmetic average roughness and a second region with a second arithmetic average roughness. This local differentiation generates visual contrast and three-dimensional perception through varying surface textures, compensating for the reduced depth available in thinner side wall portions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the surface roughness parameter (arithmetic average roughness) across different regions of the side wall portion. By controlling and varying this surface parameter rather than relying on geometric depth, the invention achieves three-dimensional visual effects and aesthetic enhancement while maintaining reduced gauge thickness for weight savings.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3900958B1Pneumatic tire
Publication Date: 2024.05.22 BRIDGESTONE CORP
  • EP3900958B1 patent drawingFigure 1
  • EP3900958B1 patent drawingFigure 2
  • EP3900958B1 patent drawingFigure 3

AI summary

A pneumatic tire (1) comprising: a tread portion (2) is in contact with a road surface; and a side wall portion (3) is continuous to the tread portion (2) and positioned inside a tire radial direction of the tread portion (2). A large region (10) comprising a plurality of small regions (11, 12 and 13) having different arithmetic average roughness outside in a tire width direction is formed on outer surface of the side wall portion (3). A plurality of large regions (10) are formed along a tire circumferential direction and the tire radial direction. In a boundary line of adjacent large region (10), small regions having different arithmetic average roughness come into contact with each other.