Two-Layer Tire Carcass for Higher Load Without Larger Size
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing passenger vehicle tires are unable to bear the increased load required for extended electric vehicle ranges without compromising vehicle roominess, compactness, and comfort, as they either require larger sizes, higher inflation pressures, or excessive carcass reinforcement tensioning.
Innovation Solution
A tire design with a higher load index than standard EXTRA LOAD tires, featuring a crown, beads, and sidewalls with a carcass reinforcement comprising two layers and specific filamentary elements, arranged to reduce tensioning and energy dissipation, maintaining the same size and comfort while supporting increased loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tire size is increased to bear greater load, then the load-bearing capacity is improved, but the vehicle interior space is reduced and exterior bulk is enlarged
Solution Approach 1:
The carcass reinforcement is divided into two separate layers (first carcass layer and second carcass layer) with different orientations. The first layer has filaments extending axially between beads, while the second layer has filaments extending circumferentially around the crown. This segmentation allows each layer to bear specific loads efficiently, enabling higher overall load capacity without increasing tire size.
Solution Approach 2:
The invention transitions from a single-layer carcass structure to a two-layer carcass structure with different spatial orientations. The first layer provides axial strength while the second layer provides circumferential strength, effectively utilizing multiple dimensions of reinforcement to achieve superior load-bearing capacity within the same tire volume.
2Strength
If the tire size is increased to bear greater load, then the load-bearing capacity is improved, but the rolling resistance and external noise increase
Solution Approach 1:
By segmenting the carcass reinforcement into two specialized layers, each optimized for its specific function, the tire achieves high load capacity without requiring an overall size increase. This prevents the increase in rolling resistance that would result from larger tire dimensions.
3Strength
If the recommended inflation pressure is increased to bear greater load, then the load-bearing capacity is improved, but the tire stiffness increases and passenger comfort is reduced
Solution Approach 1:
The two-layer carcass structure distributes the load-bearing function between axial and circumferential layers, allowing the tire to support higher loads at moderate inflation pressures. This maintains tire flexibility and passenger comfort while achieving the required load capacity.
Solution Approach 2:
The carcass reinforcement uses composite construction with two layers of filamentary reinforcement oriented differently. This composite structure provides enhanced mechanical properties, enabling the tire to bear greater loads without requiring high inflation pressures that would compromise comfort.
4Strength
If the carcass reinforcement tensioning is increased to bear greater load, then the load-bearing capacity is improved, but the energy dissipation increases
Solution Approach 1:
By dividing the carcass reinforcement into two layers with different orientations, the tensioning forces are distributed more efficiently. The axial layer handles radial loads while the circumferential layer handles tangential loads, reducing overall energy dissipation compared to a single high-tension layer.
Data Source
AI summary
The tire (11) for a passenger vehicle comprises a crown (12), two beads (32), two sidewalls (30) each connecting each bead (32) to the crown (12), and a carcass reinforcement (34) anchored in each bead (32). The tire (11) has a load index Ll such that Ll≥Ll′+1 and Ll′ being the load index of an EXTRA LOAD tire of the same size in accordance with the manual of the ETRTO 2019 standard. The tire (11) has a sidewall height H defined by H=SW×AR/100, where SW is the nominal section width and AR is the nominal aspect ratio of the tire in accordance with the manual of the ETRTO 2019 standard, such that H≥95. The carcass reinforcement (34) comprises two carcass layers (36, 37).