Pneumatic Tire Middle Land Rigidity via Segmented Grooves
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Solution Overview
Problem
Pneumatic tires with inclined grooves in the middle land portion suffer from low rigidity, which affects steering stability, and existing designs do not adequately address this issue for improved drainage and deformation suppression during cornering.
Innovation Solution
A pneumatic tire design featuring center and shoulder main grooves with middle land portions that include middle oblique grooves extending from the outer end to the inner end, where the outer end communicates with the shoulder main groove and the inner end does not, and having outer and inner shallow bottom portions with varying groove depths to enhance rigidity and drainage, along with shoulder and center lug grooves for improved stability and drainage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If middle oblique grooves extend completely across the middle land portion, then drainage performance is improved, but the rigidity of the middle land portion decreases
Solution Approach 1:
The middle oblique groove is segmented into multiple sections with different groove depths along its length. The groove has a first section with a first groove depth and a second section with a second groove depth that is different from the first groove depth. This segmentation allows different portions of the groove to serve different functions: deeper sections for drainage and shallower sections for maintaining land portion rigidity.
Solution Approach 2:
Different sections of the middle oblique groove are given different local properties through varying groove depths. The groove depth is locally adjusted along the groove length to optimize both drainage performance in certain areas and rigidity maintenance in other areas, rather than using a uniform groove depth throughout.
2Reliability
If middle oblique grooves are provided in middle land portions, then water discharge is improved, but steering stability deteriorates due to reduced rigidity
Solution Approach 1:
The middle oblique groove is divided into sections with different depths, allowing the groove to provide effective water discharge in deeper sections while maintaining land portion rigidity and steering stability through shallower sections.
Solution Approach 2:
The groove depth is locally varied along the middle oblique groove to achieve optimal balance between water discharge capability and steering stability. Specific sections have different groove depths tailored to their functional requirements.
Data Source
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AI summary
A pneumatic tire 1 is provided in the tread portion 2 with a pair of center main grooves 3 arranged on both sides of the tire equator C, and a pair of shoulder main grooves 4 arranged on both sides thereof, and is provided on both sides of the equator C with middle land portions 6 defined between the center main grooves 3 and the shoulder main grooves 4. The middle land portions 6 are provided with a plurality of middle oblique grooves 10. Each middle oblique groove 10 extends toward the tire equator C from the outer end 10o in the tire axial direction communicating with the shoulder main groove 4, and the inner end 10i terminates without reaching to the center main groove 3. In an outer end 10o side of the middle oblique groove 10, an outer shallow bottom portion 12 having a depth less than the maximum depth of the middle tilted groove 10 is provided.