Variable-Depth Tread Grooves for Tire Noise and Wear Balance
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Solution Overview
Problem
Existing pneumatic tires with uniform deep main grooves generate excessive noise and require improvement in noise performance while maintaining wear resistance.
Innovation Solution
The tire design features grooves with varying depths optimized based on ground contact lengths, with groove depths defined by a virtual line system and correction coefficients to reduce noise and maintain wear resistance, applicable to various vehicles including passenger cars and heavy-duty vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform deep main grooves are used in the tread portion, then wear resistance is improved, but noise generation increases
Solution Approach 1:
The patent applies local quality by varying the groove depth according to the axial position on the tread width. The groove depth is set to be larger at the crown portion (center) and smaller at the shoulder portions (sides), creating different local characteristics that simultaneously achieve wear resistance at the crown and noise reduction at the shoulders. This is accomplished by defining a reference line that curves upward from the shoulders toward the crown, with groove bottoms positioned relative to this line.
Solution Approach 2:
The patent changes the geometric parameter of groove depth along the axial direction of the tread. Instead of maintaining a constant groove depth, the depth varies continuously or discontinuously from the crown to the shoulders. This parameter change is achieved by positioning groove bottoms at different radial distances from the tread outer surface based on their axial position, thereby optimizing both wear resistance and noise performance.
2Object-generated harmful factors
If groove depths are varied to reduce noise, then noise performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining a reference line (or multiple reference lines) that establishes the desired groove depth variation pattern before actual groove formation. This reference line, which curves upward from shoulders to crown, serves as a template that guides the groove manufacturing process, allowing complex variable-depth grooves to be created using standard manufacturing techniques without requiring complex real-time control during production.
Data Source
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AI summary
A tire comprises a tread portion provided with grooves. When the tire mounted on a standard wheel rim and inflated to a standard tire pressure is placed on a flat surface at a camber angle of zero and loaded with a standard tire load, the tire has a ground contacting patch. The depths of the respective grooves, and ground contact lengths of the ground contacting patch measured at axial positions of the respective grooves, are in a relationship in which the groove depth increases or decreases as the ground contact length increases or decreases.