Pneumatic Tire Flank Geometry for Boundary Layer Control
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Solution Overview
Problem
Pneumatic vehicle tires experience increased air resistance and noise due to undefined turbulence and boundary layer separation at high speeds, primarily caused by the smooth transition between the tread profile and sidewall, leading to inefficient energy consumption.
Innovation Solution
The design of a pneumatic vehicle tire with a tread profile that features radially curved profile elements with a targeted tear-off edge, defined by specific angles of inclination, which breaks off the boundary layer and reduces turbulence, incorporating a flank with angles α (80° ≤ α ≤ 100°) and β (45° < β ≤ 60°) to the tangent and radial direction respectively, and a spoiler lip that slides on incoming air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the profile elements have a smooth transition to the tire sidewall, then the optical appearance is improved, but air resistance and noise increase due to undefined turbulence and boundary layer separation
Solution Approach 1:
The patent applies preliminary action by pre-defining the boundary layer detachment point through the flank geometry before the air flow reaches it. The flank with specific angles (α: 80°-100°, β: 45°-60°) is designed in advance to control where and how the boundary layer separates, preventing undefined turbulence. This pre-controlled separation point eliminates the random eddies that would otherwise form in smooth transitions, reducing drag and noise while maintaining aesthetic appearance.
2Illumination intensity
If finely designed grooves are added to the transition area, then the optical appearance is improved, but additional turbulence and boundary layer separation occur increasing air resistance
Solution Approach 1:
The patent converts the potentially harmful effect of boundary layer separation into a beneficial controlled process. Instead of trying to prevent separation entirely (which would require complex grooves), the flank geometry is designed to guide the separation in a predictable, streamlined manner. The specific angle ranges (α: 80°-100°, β: 45°-60°) ensure that separation occurs cleanly along the flank surface, transforming what could be turbulent chaos into organized flow that reduces drag and noise while still providing visual definition to the transition area.
3Speed
If the profile elements are curved on their radially outward-facing surface, then the aerodynamic flow is improved, but undefined turbulence and detachment occur increasing noise generation
Solution Approach 1:
The patent applies local quality by differentiating the surface characteristics in different zones. The radially outward-facing surface is curved to guide airflow smoothly, while the flank region introduces a specific geometric discontinuity with controlled angles (α: 80°-100°, β: 45°-60°). This localized geometric feature acts as a flow controller, creating a defined separation point that prevents the formation of turbulent eddies and noise-generating vortices downstream, thus reducing noise while maintaining high-speed aerodynamic performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces air resistance and noise by minimizing unwanted turbulence and flow detachment, enhancing energy efficiency and reducing noise generation, particularly advantageous at high speeds.
Implementation Method 1
the incoming air flows along the curved surface of these profile elements, which are curved in the off-shoulder area, and the sidewall. The smooth surfaces in this transition formed in the area of the curvature cause undefined turbulence and detachment of the boundary layer
Implementation Method 2
The smooth surfaces in this transition formed in the area of the curvature cause undefined turbulence and detachment of the boundary layer
Data Source
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AI summary
The vehicle pneumatic tire has a tread profile, two tire side walls (9) and profile elements. The profile elements extend in an axial direction towards the tire side wall till an edge (10) that is extended in a circumferential direction of the vehicle pneumatic tire with their radial outer curved surfaces. The radial outer surface of the tire side wall extends from the flank running out from radial inside up to the mounting section of the tire.