Pneumatic Tire Side Protectors with Grooved Projections
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Solution Overview
Problem
Pneumatic tires face challenges in balancing durability of the bead portion, off-road performance, and cut resistance, as increasing the height of side protectors for improved traction and mud shearing leads to increased tire weight and reduced bead durability.
Innovation Solution
The tire design features side protectors with grooved portions between them, where the grooved portion length is between 50% to 70% of the side protector length, and includes projections with a triangular shape and controlled height to enhance traction and cut resistance while maintaining bead durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the side protectors are increased in the protruding height to improve off-road performance and cut resistance, then the tractional force and mud shearing capability are improved, but the tire weight is unfavorably increased and the durability of the bead portion is deteriorated
Solution Approach 1:
The side protectors are designed with non-uniform cross-sectional areas along their axial direction, with the cross-sectional area being larger in the radially outer region and smaller in the radially inner region. This local variation in geometry allows the side protectors to provide enhanced cut resistance and traction where needed (in the radially outer region) while reducing rubber volume and weight in the radially inner region near the bead portion.
2Reliability
If the side protectors are increased in the protruding height to improve off-road performance, then the engagement and friction with rocks is improved, but the flexural stress of the sidewall portion concentrates in the bead portion region and the durability is deteriorated
Solution Approach 1:
The side protectors feature a gradient cross-sectional area design where the area is larger in the radially outer region for improved rock engagement and smaller in the radially inner region. This reduces the rubber volume in the bead portion region, thereby reducing flexural stress concentration and improving bead durability while maintaining off-road performance.
Solution Approach 2:
The side protectors are designed with a three-dimensional gradient structure where the cross-sectional area varies along the axial direction. This dimensional variation allows optimization of both off-road performance (through larger outer dimensions) and bead durability (through smaller inner dimensions), resolving the contradiction by utilizing the third dimension (radial position) to distribute stress differently.
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 improves off-road performance and cut resistance while maintaining the durability of the bead portion by optimizing the volume and distribution of rubber, reducing weight, and preventing cut damage.
Implementation Method 1
the side protectors can exert tractional force by the engagement and friction between the side protectors and rocks on the rocky ground
Implementation Method 2
by the shearing of the mud entered into reentrant portions formed between the side protectors
Data Source
AI summary
A pneumatic tire comprises a sidewall portion provided in its radially outer region B with side protectors protruding axially outwardly from the outer surface Ba of the radially outer region B. The side protectors are arranged in the tire circumferential direction at intervals so that grooved portions are formed between the side protectors. The width W1 in the tire circumferential direction of the grooved portion is in a range of from 50% to 70% of the width W2 in the tire circumferential direction of the side protector when measured at the same radial position.