Pneumatic Tire Tread Segmentation for Rough Terrain Stability
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Solution Overview
Problem
Pneumatic tires for off-road vehicles face challenges in improving stability and controllability without compromising ride comfort and ground contact feeling, as existing techniques either increase block size or rubber hardness, which negatively affect performance on both rough terrain and paved roads.
Innovation Solution
A pneumatic tire design featuring a tread portion with crown blocks, shoulder blocks, and middle blocks, where crown blocks have shifted subdivisions to enhance cornering friction, and middle and shoulder blocks include U-shaped cuts to increase edge components, thereby improving stability and controllability without increasing block size or rubber hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If block size is increased to increase edge effect, then stability and controllability improve, but ride comfort deteriorates
Solution Approach 1:
The patent divides blocks into multiple segments by forming grooves (U-shaped cuts) within the blocks, creating subdivided block pieces. This segmentation increases the effective edge length and edge effect without increasing the overall block size, thereby improving stability and controllability while maintaining ride comfort on paved roads.
Solution Approach 2:
The patent introduces circumferential shifting of block pieces relative to each other in the tread pattern design. This dimensional arrangement creates additional edge components and increases the effective edge length in the circumferential direction, enhancing cornering performance and stability without increasing block size or hardness.
2Reliability
If rubber hardness of blocks is increased to improve grip performance, then stability and controllability improve, but ground contact feeling deteriorates
Solution Approach 1:
The patent segments blocks into multiple block pieces using grooves, which increases the effective edge length and grip performance through enhanced edge effect. This allows maintaining softer rubber composition for better ground contact feeling while achieving improved stability through the segmented structure's increased edge components.
3Reliability
If block size is increased to increase edge length, then cornering performance improves, but ride comfort on paved road deteriorates
Solution Approach 1:
The patent forms U-shaped cuts within blocks to create subdivided block pieces, increasing the effective edge length available for cornering without increasing the overall block size. This segmentation provides improved cornering performance while maintaining smaller block dimensions that preserve ride comfort on paved roads.
Solution Approach 2:
The patent employs circumferential shifting of block pieces to create additional edge components in the circumferential direction. This dimensional arrangement enhances cornering performance through increased effective edge length without requiring larger block sizes that would compromise ride comfort on paved surfaces.
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
The tire design enhances traction and braking performance during straight running and cornering, maintaining ride comfort and ground contact feeling, as evidenced by improved traction and grip performance in off-road conditions.
Implementation Method 1
the circumferential component of their edges effective when cornering is increased to increase the frictional force
Implementation Method 2
the inside part of the cut block can move relatively to the outside part, therefore, the effective edge length or edge effect is increased
Data Source
AI summary
A pneumatic tire for running on rough terrain is provided in the tread portion with crown blocks, middle blocks and shoulder blocks. Aspect ratios of the crown blocks are less than those of the middle blocks and shoulder blocks. The crown blocks include shifted blocks provided with a slot to form two subdivided block pieces circumferentially shifted from each other. The middle blocks and the shoulder blocks including cut blocks provided with a U-shaped cut opened at the top face and a side face of the block.