Pneumatic Tire Tread Cap Layer Groove Ratio
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Solution Overview
Problem
Existing pneumatic tires fail to achieve optimal quietness while maintaining required steering stability and rollover resistance, especially in electric vehicles, due to limitations in tread design and internal pressure management.
Innovation Solution
A pneumatic tire design featuring a tread with a base layer and cap layer structure, where the cap layer includes a center element and side elements with varying hardness, and a specific arrangement of circumferential and lateral grooves, along with open and dead-end sipes, to reduce noise and maintain stiffness balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lateral grooves with width of 2.0 mm or greater are formed on the shoulder land portion to improve wet road performance, then drainage capability is improved, but noise is generated due to air passing through the grooves
Solution Approach 1:
The patent changes the physical parameters of the lateral grooves by limiting their width to 2.0 mm or less and controlling the area ratio to 3% or less. This parameter optimization allows the grooves to maintain drainage functionality while preventing excessive air flow that causes noise, thus resolving the contradiction between wet road performance and noise reduction.
Solution Approach 2:
The patent applies different groove configurations to different regions of the tread. The shoulder land portion has lateral grooves with specific constraints (width ≤2.0 mm, area ratio ≤3%), while other regions may have different configurations. This localized quality differentiation allows optimal performance in each region without compromising overall quietness.
2Object-generated harmful factors
If the tread structure is designed with multiple grooves and sipes to improve quietness, then noise is reduced, but steering stability and rollover resistance may be compromised
Solution Approach 1:
The patent optimizes the area ratio of lateral grooves to be 3% or less of the shoulder land portion area. This precise parameter control ensures that enough tread land remains to maintain steering stability and rollover resistance while still providing sufficient groove area for noise reduction through air flow management.
Solution Approach 2:
The patent uses a composite tread structure with base layer and cap layer, where the cap layer contains the lateral grooves. This composite structure allows the grooves to function for noise reduction while the overall tread composition maintains the necessary stiffness and stability for safe vehicle operation.
Data Source
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AI summary
In a tire 2, a cap layer 30 of a tread 4 includes a center element 32 and a pair of side elements 34. Each side element 34 is more flexible than the center element 32. A plurality of lateral grooves 60 each having a groove width of 2.0 mm or greater are formed on each shoulder land portion 58s of the tread 4. In a ground-contact surface obtained by pressing the tire 2 in a normal state against a road surface at a load equal to 68% of a normal load, a ratio of areas of the lateral grooves 60 included in a ground-contact surface of the shoulder land portion 58s to an area of the ground-contact surface of the shoulder land portion 58s is not greater than 3%. The cap layer 30 in the shoulder land portion 58s includes the side element 34.