Asymmetric Tread Block Step Design for Snow Tire Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pneumatic snow tires face challenges in balancing snow performance with braking and handling stability on dry roads, as increasing lug groove width for improved snow performance reduces block rigidity, leading to heel-and-toe wear issues.
Innovation Solution
The tire features a block design with a first step portion on the dig-in side and a second step portion on the kick-out side, where the second step portion has a smaller width and greater height than the first, providing increased rigidity and shear force for snow performance while minimizing heel-and-toe wear by suppressing deformation during traction or braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the width of lug grooves is increased to improve snow performance, then snow performance is improved, but block rigidity is reduced
Solution Approach 1:
The patent applies local quality by creating asymmetric step portions at different locations on the block. The first step portion is provided at the dig-in side with specific dimensions, while the second step portion is provided at the kick-out side with different dimensions. This local differentiation allows the block to have varied rigidity characteristics in different regions, enabling it to maintain overall rigidity while accommodating wide lug grooves for snow performance.
Solution Approach 2:
The patent employs asymmetry by making the first and second step portions have different widths and/or heights. The first step portion extends along one side wall portion of the block, while the second step portion extends along the other side wall portion with asymmetric dimensions. This asymmetric configuration allows the block to optimize both snow engagement (through wide grooves) and structural integrity (through strategically placed rigid step portions).
2Reliability
If block rigidity is reduced to increase lug groove width, then snow performance is improved, but heel-and-toe wear occurs
Solution Approach 1:
The asymmetric step portions create local quality variations in the block structure. The first step portion at the dig-in side and the second step portion at the kick-out side have different dimensions, providing localized rigidity enhancement where needed. This prevents uniform block deformation that would otherwise cause heel-and-toe wear, while still allowing sufficient groove width for snow performance.
Solution Approach 2:
The step portions are designed in advance to counteract the deformation that would lead to heel-and-toe wear. By providing these rigid step portions before the block is subjected to traction and braking forces, the structure is pre-configured to resist the asymmetric loads that cause wear, thereby preventing the harmful effect before it occurs.
3Ease of manufacture
If symmetric step portions are provided at both side wall portions of the block, then manufacturing is simplified, but snow performance is reduced
Solution Approach 1:
The patent deliberately introduces asymmetry in the step portion dimensions to optimize snow performance. The first step portion and second step portion have different widths and/or heights, creating an asymmetric configuration that enhances the block's ability to engage with snow columns. This asymmetric design, while slightly more complex to manufacture, provides superior snow traction compared to symmetric designs.
Data Source
AI summary
Heel-and-toe wear can be suppressed while securing snow performance. Includes: a block (14) that is provided at a tread (16), and that is demarcated by mutually intersecting circumferential direction main grooves (22) and lateral main grooves (24) (main grooves) respectively extending around a tire circumferential direction and along a tire width direction; a first step portion (11) that extends along a wall portion (14F) at one tire circumferential direction side of the block (14), and that has a height from a groove bottom (24A) of the lateral main groove (24) (main groove) where the one side wall portion (14F) is present, which is lower than a tread face (14A); and a second step portion (12) that extends along a side wall portion (14R) at another tire circumferential direction side of the block (14), that has a height from a groove bottom (24A) of the lateral main groove (24) (main groove) where the other side wall portion (14R) is present, which is lower than the tread face (14A), and that has a smaller width than the first step portion (11).