Multi Cap Tire Tread Notched Layer Design
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Solution Overview
Problem
As a tire wears, the volume of the tread and grooves decreases, leading to reduced wet road performance due to decreased water channeling ability, even if the tire has not reached the legal minimum non-skid depth.
Innovation Solution
A pneumatic tire with a tread comprising three layers: a radially outer tread cap layer for improved wet traction, a middle tread cap layer for low rolling resistance, and a base tread layer, featuring notched areas that maintain contact with the road as the tire wears, ensuring consistent wet and dry performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tire tread wears down, then the volume of the tread and grooves decreases, but the wet road performance deteriorates due to reduced water channeling ability
Solution Approach 1:
The tread is segmented into multiple functional layers: a base tread layer and a wet traction tread cap layer. This segmentation allows each layer to perform its specific function - the base layer provides structural support while the cap layer maintains wet traction performance throughout tire life by extending into the grooves.
Solution Approach 2:
The wet traction tread cap layer extends vertically into the grooves, utilizing the third dimension (depth) to maintain water channeling capability. This vertical extension ensures that the wet traction compound remains in contact with the road surface even as the tire wears, preserving wet road performance beyond the traditional non-skid depth limit.
2Duration of action of moving object
If the non-skid depth is reduced to extend tire life, then the tire can be used longer, but the wet road performance is severely limited before reaching legal minimum depth
Solution Approach 1:
The wet traction tread cap layer is pre-positioned to extend into the grooves at the factory, creating a reservoir of wet traction material that will be progressively exposed as the tire wears. This preliminary configuration ensures wet performance is maintained throughout the entire tire life, not just when new.
Solution Approach 2:
The invention changes the depth parameter of the tread cap layer, extending it below the traditional non-skid depth into the groove areas. This parameter change allows the wet traction material to remain effective at lower non-skid depths, extending the functional life of the tire while maintaining wet road performance.
3Reliability
If a single compound is used for the entire tread, then the manufacturing is simpler, but the tire cannot simultaneously optimize both wet traction and rolling resistance
Solution Approach 1:
Different regions of the tread are assigned different compounds based on their specific functions. The base tread layer uses a compound optimized for rolling resistance and durability, while the wet traction cap layer uses a compound specifically formulated for wet grip. This local differentiation of material properties allows simultaneous optimization of multiple performance parameters.
Solution Approach 2:
The tread is constructed as a composite structure with two distinct rubber compounds: a base tread compound and a wet traction tread cap compound. This composite approach combines the advantages of different material formulations, achieving both low rolling resistance and excellent wet traction performance in a single tire tread system.
Data Source
Figure 1
AI summary
A tire tread (10) comprising one or more grooves (19, 22, 24, 28) is disclosed. The tread (10) has a radially outer surface and a non-skid tread depth as measured from the radially outer surface of the tread (10) to the radially innermost surface of the one or more grooves (19, 22, 24, 28). Furthermore, the tread (10) has a radially innermost layer (70) comprising of a base tread compound, a radially outer tread cap layer (50) and a middle tread layer (60) located between the base layer (70) and the outer tread cap layer (50). The radially outer tread cap layer (50) has a defined thickness (D) except that the radially outer tread cap layer (50) comprises at least one notched area (75, 80) wherein the radially outer tread cap layer (50) extends radially inward of the defined thickness (D). Also, a pneumatic tire comprising such a tire tread is disclosed.