Tire Frame Warping Mitigation via Localized Groove Segmentation

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Solution Overview

Problem

The existing tire manufacturing process using thermoplastic resins and rubber materials results in warping of the tire frame member's outer circumferential portions due to the transmission of pressing force from the tread to the reinforcing belt, leading to potential vibrations during vehicle operation.

Innovation Solution

A tire design featuring a thermoplastic resin frame member with a reinforcing layer and a rubber tread, incorporating width direction grooves with minimal aperture surface area and reduced compression rigidity portions to mitigate warping and enhance water drainage and vibration reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a belt is provided on the inner side of the tread, then the tire frame member is reinforced, but the belt warps over a wide extent in the tire circumferential direction causing vibrations

Engineering Contradiction:
Improvetire frame member reinforcementVSAvoidvibrations from belt warping
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by providing recessed portions only in specific regions where warping occurs, rather than uniformly modifying the entire tread. The recessed portions are strategically placed in the circumferential direction at locations corresponding to mold projections that cause belt warping, while maintaining the original tread structure in other areas. This localized modification reduces warping-induced vibrations without compromising overall tire performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tread is segmented into multiple regions by introducing recessed portions that divide the continuous tread structure. These recessed portions create discrete zones that prevent the warping effect from propagating across the entire circumferential direction, effectively segmenting the warping phenomenon into isolated areas that do not cause system-wide vibrations.

Inventive Principle:
Principle #1Segmentation

2Difficulty of detecting and measuring

If width direction grooves are provided in the tread, then water drainage is improved, but the aperture surface area increases reducing ground contact

Engineering Contradiction:
Improvewater drainage capabilityVSAvoidground contact surface area
Core Design Contradiction:
Difficulty of detecting and measuringVSArea of stationary object

Solution Approach 1:

The patent applies the porous materials principle by incorporating width direction grooves that create a porous-like structure in the tread surface. These grooves allow water to drain through the tread while maintaining sufficient solid contact area. The grooves are designed with specific dimensions and spacing to balance water drainage efficiency with ground contact area, ensuring that the aperture surface area remains within acceptable limits while still providing effective water evacuation.

Inventive Principle:
Principle #31Porous materials

3Difficulty of detecting and measuring

If the aperture surface area of width direction grooves is increased, then water drainage improves, but warping reduction effect decreases

Engineering Contradiction:
Improvewater drainage efficiencyVSAvoidbelt warping extent
Core Design Contradiction:
Difficulty of detecting and measuringVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the aperture surface area of width direction grooves to be within a specific range (0.01% to 5% of the tread surface area). This parameter optimization ensures that the grooves are sufficiently large to drain water effectively while remaining small enough to minimize their impact on belt warping. The recessed portions are also designed with specific depth and spacing parameters to achieve the desired balance between water drainage and warping reduction.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3388258B1tire
Publication Date: 2020.02.19 BRIDGESTONE CORP
  • EP3388258B1 patent drawingFigure 1
  • EP3388258B1 patent drawingFigure 2
  • EP3388258B1 patent drawingFigure 3

AI summary

A tire includes a tire frame member that is formed from a resin material and has a bead portion, side portions, and a crown portion, a belt layer serving as an example of a reinforcing layer that is disposed at the outer side in a tire radial direction of the tire frame member, and has a higher bending rigidity than outer circumferential portions of the tire frame member, a top tread serving as an example of a tread that is formed from a rubber material and is disposed at the outer side in the tire radial direction of the belt layer, and first width direction grooves serving as an example of width direction grooves that are provided at the top tread. An aperture surface area of one of the first width direction grooves within a total ground contact surface of the tread of one circumferential direction portion of the tire is 0.02% or less relative to a surface area of a total ground contact surface of the tread of one circumferential portion of the tire.