U-Shaped Tread Blocks With Lateral Slots for Rough Terrain Handling

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Solution Overview

Problem

Pneumatic tires for off-road vehicles often experience undesirable handling during cornering due to high rigidity in the tread blocks, which compromises the grip and traction performance on rough terrain.

Innovation Solution

The tire design incorporates U-shaped blocks with lateral slots and chamfered portions in the tread pattern, featuring a combination of center, shoulder, and middle blocks with specific edge configurations and slot dimensions to reduce axial rigidity while maintaining high grip and traction, thereby enhancing handling and self-cleaning capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tread blocks are arranged sparsely with deep engagement for off-road use, then grip and traction performance on rough terrain is improved, but handling feeling deteriorates due to high rigidity in axially outer portion

Engineering Contradiction:
Improvegrip and traction performanceVSAvoidhandling feeling
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The tread block is segmented by introducing a lateral slot that divides the axially outer portion into multiple sections. This segmentation reduces the rigidity of the axially outer portion while maintaining the overall block structure, allowing the block to deform more easily during cornering and improve handling feeling without sacrificing grip performance on rough terrain

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies different structural characteristics to different regions of the tread block. The axially outer portion contains the lateral slot to reduce rigidity for better handling, while the axially inner portion maintains sufficient rigidity for stable cornering. This local differentiation of mechanical properties resolves the contradiction between handling responsiveness and cornering stability

Inventive Principle:
Principle #3Local quality

2Ease of operation

If lateral slot is introduced to reduce rigidity for better handling, then handling feeling is improved, but grip performance may deteriorate

Engineering Contradiction:
Improvehandling feelingVSAvoidgrip performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The lateral slot dimensions are carefully controlled with specific parameter ranges: width at top face of 0.05 to 0.20 times the circumferential maximum length, and axial length at top face of 0.08 to 0.40 times the axial maximum length. These parameter optimizations ensure the slot reduces rigidity sufficiently for improved handling while maintaining enough structural integrity to preserve grip performance on rough terrain

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2682283B1Pneumatic tire for running on rough terrain
Publication Date: 2017.03.15 SUMITOMO RUBBER INDUSTRIES LTD
  • EP2682283B1 patent drawingFigure 1
  • EP2682283B1 patent drawingFigure 2
  • EP2682283B1 patent drawingFigure 3

AI summary

A pneumatic tire for rough terrain comprises a tread portion provided with a plurality of blocks, the blocks comprising a plurality of center blocks arranged in a center region of the tread portion, a plurality of shoulder blocks arranged along each tread edge of the tread portion and a plurality of middle blocks arranged between the center region and the shoulder blocks, each of the center blocks, middle blocks and shoulder blocks comprising a top face and a sidewall face extending radially inward from the peripheral edge of the top face, wherein at least one of the middle blocks and shoulder blocks is a U-shaped block having a lateral slot which extends from an axially outer sidewall face of the block to an axially inner end thereof being terminated within the block.