Tire Sipe Design for Block Rigidity and Road Performance

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Solution Overview

Problem

Conventional tires with many sipes for improved ice and snow performance suffer from reduced rigidity, compromising braking and cornering performance on non-ice and snow roads, and are costly to manufacture.

Innovation Solution

A tire design featuring sipes that are inclined in the tire radial direction, with a specific shape and configuration that includes a first sipe, a bent portion, and a second sipe, which enhances rigidity and contact pressure distribution, allowing for improved performance on both ice and snow roads and non-ice and snow roads while being efficient to manufacture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If many sipes are formed in a block to improve ice and snow road performance, then traction and braking performance on ice and snow roads are improved, but rigidity of the block is deteriorated

Engineering Contradiction:
Improveice and snow road performanceVSAvoidblock rigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The sipe is designed with different inclination angles in different regions: the intermediate portion (at depth 0.3-0.7 from tread surface) has a larger inclination angle (10-20 degrees) to maintain block rigidity, while the other portions have smaller inclination angles (5-15 degrees) to provide effective ice and snow road performance. This local differentiation allows each region of the sipe to serve its specific function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sipe is designed with three-dimensional curvature, transitioning from a simple linear groove to a complex spatial structure with varying inclination angles at different depths and positions. This dimensional transformation allows the sipe to simultaneously achieve rigidity support in the intermediate portion and effective snow/ice interaction at the surface and bottom portions.

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

2Reliability

If sipes are formed to improve ice and snow road performance, then traction on ice and snow roads is improved, but wear resistant performance on non-ice and snow roads is deteriorated

Engineering Contradiction:
Improveice and snow road tractionVSAvoidwear resistant performance
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The intermediate portion of the sipe with larger inclination angle (10-20 degrees) provides structural support and reduced contact area, decreasing wear on non-ice and snow roads, while the other portions with smaller inclination angles (5-15 degrees) maintain effective contact for ice and snow road traction.

Inventive Principle:
Principle #3Local quality

3Reliability

If conventional sipe designs are used to improve ice and snow performance, then braking performance on ice and snow roads is improved, but manufacturing cost increases

Engineering Contradiction:
Improvebraking performance on ice and snow roadsVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The blade is designed with a curved surface that dynamically forms the three-dimensional sipe structure during molding. The curvature radius varies along the blade length (R1=0.5-2.0mm at intermediate portion, R2=1.0-3.0mm at other portions), allowing the blade to create the complex sipe geometry in a single continuous motion, simplifying the manufacturing process.

Inventive Principle:
Principle #15Dynamics

4Ease of manufacture

If sipes with uniform inclination are used, then manufacturing is simplified, but both ice and snow road performance and non-ice and snow road performance cannot be simultaneously optimized

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmulti-road performance
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The sipe is designed with different inclination angles in different regions: the intermediate portion has a larger inclination angle (10-20 degrees) optimized for block rigidity and wear resistance on non-ice and snow roads, while the other portions have smaller inclination angles (5-15 degrees) optimized for ice and snow road performance, allowing the single sipe structure to adapt to multiple road conditions.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3446891B1Tire and tire mold
Publication Date: 2020.09.02 BRIDGESTONE CORP
  • EP3446891B1 patent drawingFigure 1
  • EP3446891B1 patent drawingFigure 2
  • EP3446891B1 patent drawingFigure 3~4

AI summary

The projection portion 150 includes a straight portion 152 extended linearly in a predetermined direction, a first inclined portion 151 inclined to spread toward an outer side in the predetermined direction from one end of the straight portion 152, and a second inclined portion 153 inclined to spread toward an outer side in the predetermined direction from another end of the straight portion 152. A period defined by a length of the projection portion 150 in the predetermined direction is 0.8 times to 2.0 times as large as a sipe depth defined by a length of the sipe 100A between the wheel tread of a block 20A and a bottom of the sipe 100A.