Tyre Carcass Ply Layout for Lower Rolling Resistance

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Solution Overview

Problem

Existing vehicle tires face a trade-off between maintaining high efficiency and reducing rolling resistance, with the radial outer carcass layer contributing to increased weight and rolling resistance while dissipating energy during power flow.

Innovation Solution

The outer carcass ply ends are positioned within a minimal distance of up to 20.0 mm from the inner carcass ply upturn, with specific angles and orientations of the carcass cords to minimize energy dissipation and weight increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a radial outer carcass layer is added to improve sidewall stiffness and efficiency, then sidewall stiffness is improved, but rolling resistance and weight increase

Engineering Contradiction:
Improvesidewall stiffnessVSAvoidtire weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The invention extracts the outer carcass layer from the conventional design by positioning its ends within 20.0 mm of the inner carcass layer upturn, effectively removing unnecessary material while preserving the critical stiffness function in the upper sidewall area

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The outer carcass layer is strategically positioned to provide localized stiffness enhancement in the upper sidewall region where it is most needed for efficiency, rather than uniformly throughout the entire sidewall, thereby minimizing overall weight increase

Inventive Principle:
Principle #3Local quality

2Loss of energy

If a radial outer carcass layer is added to maintain high efficiency, then energy dissipation is minimized, but rolling resistance increases

Engineering Contradiction:
Improveenergy dissipationVSAvoidrolling resistance
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The outer carcass layer is extracted to the minimal necessary extent, with ends positioned within 20.0 mm of the inner layer upturn, removing excess material that would contribute to rolling resistance while maintaining the energy dissipation benefits in critical areas

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of implementing a full outer carcass layer throughout, the invention applies partial action by positioning the layer ends close to the upturn, providing just enough structural support to minimize energy dissipation during power flow without the excessive material that would increase rolling resistance

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4647274A1Vehicle tyre
Publication Date: 2025.11.12 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP4647274A1 patent drawingFigure 1
  • EP4647274A1 patent drawingFigure 2
  • EP4647274A1 patent drawingFigure 3~4

AI summary

The invention relates to a vehicle tire with a carcass insert (5) consisting of an inner carcass layer (10) and an outer carcass layer (11, 12) offset from the inner carcass layer (10) in the direction of the tire's outer surface and in contact with the inner carcass layer (10), wherein the inner carcass layer (10) is folded around the bead core (7) in each bead area (6) and has a layer fold (10a) with a fold end (10a'), wherein the outer carcass layer (11, 12) extends radially outside the core riders (8) without wrapping around the bead cores (7) in contact with the inner carcass layer (10) and has two carcass layer ends (11b', 12b').The carcass ply ends (11b', 12b') of the outer carcass ply (11, 12) lie in the area of ​​the respective side wall (3), wherein each carcass ply end (11b', 12b') is located within a distance (a1, a2) of up to 20.0 mm, determined as the smallest possible distance, with respect to the upturn end (10a') of the ply upturn (10a) of the inner carcass ply (10).