Pneumatic Tire Crown Corrugations and Low-Rigidity Rubber for Grip
Solution Overview
Problem
Tires face a trade-off in performance criteria such as wear, grip on different surfaces, rolling resistance, and dynamic behavior, where soft rubber compounds for good dry grip compromise rigidity and increase noise, while stiffening the rubber or reducing tread depth affects wet grip and wear.
Innovation Solution
A touring tire design featuring a tread with major grooves and a crown reinforcement layer with corrugations, using a low-rigidity rubber compound overhanging undulations to enhance grip and reduce rolling resistance without compromising wear or endurance, while maintaining acceptable rolling resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If soft rubber compounds are used in the tread, then dry grip is improved, but rigidity decreases and noise increases
Solution Approach 1:
The patent applies different rubber compound rigidities to different regions of the tread. Soft rubber compounds (low rigidity) are used in specific zones to enhance dry grip, while stiffer rubber compounds are used in other areas to maintain overall tire rigidity and reduce noise. This spatial differentiation of material properties resolves the contradiction between local grip enhancement and global structural stability.
2Stability of the object's composition
If the rubber compound is stiffened, then rigidity is improved, but dry grip and wet grip deteriorate
Solution Approach 1:
The patent implements a multi-zone tread design where different rubber compounds with varying rigidity levels are assigned to specific functional zones. Soft, compliant rubber compounds are placed in contact patches optimized for grip, while stiffer compounds are positioned in areas requiring structural support. This localized material differentiation allows the tire to simultaneously achieve high rigidity and excellent grip performance without compromise.
3Loss of energy
If tread depth is reduced, then rolling resistance is improved, but wear performance and wet grip deteriorate
Solution Approach 1:
The patent optimizes the tread depth parameter by designing a specific depth profile that balances rolling resistance and wear performance. The tread depth is engineered to maintain sufficient contact patch area for wear resistance and wet grip while being optimized to minimize deformation losses and rolling resistance. This parameter optimization allows the tire to achieve low rolling resistance without sacrificing durability or wet surface performance.
Data Source
Figure 1~2
Figure 3~4d
AI summary
The invention relates to a pneumatic tire comprising a crown having at least one layer of reinforcing elements. The radially outermost layer includes at least one wave (512). The waves (512) of the radially outermost layer (5) are such that, for each meridian, radially inward from the center of the bottom surface (243) of the closest main groove (24), the points of the waves lie radially outside the points of said layer (5) by at least a radial distance of 1.5 mm. The waves (512) of the radially outermost crown layer constitute at least 10% of the radially outer surface (SRE) of said crown layer (5). A rubber compound having a maximum dynamic shear modulus G *, measured at 40°C at 10% peak-to-peak deformation at 10 Hz, of 3.25 MPa, constitutes at least 30% of the rubber compounds lying on top of said waves.