Asymmetric Lug Tread Design for Tractor Tire Wear and Traction
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Solution Overview
Problem
Tires for agricultural tractors face challenges in achieving a balance between field traction, wear resistance, and vibratory comfort, with existing designs often leading to irregular wear and premature tire removal due to the compromise between lug sizes and patterns.
Innovation Solution
A tire design featuring a tread with alternating long and short lugs in chevron or offset-V patterns, where the axially inner end face of a long lug is separated from the trailing lateral face of a symmetrical long lug by an end groove, providing structural continuity and stiffening, and optionally filled with an elastomeric linking element for enhanced traction and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If alternating long and short lugs are used in the tread, then field traction is improved, but wear resistance deteriorates due to irregular wear patterns
Solution Approach 1:
The tread features alternating long and short lugs arranged asymmetrically in the circumferential direction, creating an offset pattern where long lugs in one row are offset from long lugs in adjacent rows. This asymmetric arrangement improves field traction by providing varied contact patches while the offset configuration ensures more uniform wear distribution across the tread, resolving the contradiction between traction performance and wear resistance
Solution Approach 2:
The tread is segmented into multiple rows of lugs with varying lengths (long and short lugs) arranged in an alternating pattern. This segmentation creates diverse contact areas that enhance traction in different field conditions while distributing wear across multiple segments, preventing concentrated wear at specific locations and extending tire service life
2Productivity
If larger lugs are used to improve field traction, then traction performance is improved, but rolling resistance and vibratory comfort on road deteriorate
Solution Approach 1:
The tread employs local quality variation by incorporating both long and short lugs in different circumferential positions and rows. The long lugs provide enhanced traction in field conditions where greater penetration is needed, while the short lugs reduce rolling resistance and improve vibratory comfort on road surfaces. This local differentiation allows the tire to optimize performance for specific operating conditions without compromising overall efficiency
3Ease of manufacture
If symmetric lug arrangement is used, then manufacturing is simplified, but wear uniformity deteriorates leading to premature tire removal
Solution Approach 1:
The invention deliberately introduces asymmetry in the circumferential arrangement of lugs, where long lugs in one row are offset from long lugs in adjacent rows by a specific distance (e.g., half the pitch between corresponding lugs). This asymmetric offset pattern, while more complex than perfect symmetry, creates uniform wear distribution across the tread by ensuring that no single area bears excessive load, thereby extending tire life despite increased manufacturing complexity
Data Source
AI summary
A tread and tire for a multipurpose agricultural machine, that improves field traction while ensuring a satisfactory compromise with wear under engine torque and vibratory comfort on the road having a tread having a plurality of lugs distributed in a first row extending axially from a first axial end of the tread and in a second row extending axially from a second axial end of the tread, the second row differing from the first row by a symmetry relative to the equatorial plane of the tire followed by a rotation about the rotation axis of the tire, each row having an alternation of long lugs and of short lugs. The axially inner end face of a first long lug of a row of lugs is separated from the trailing lateral face of the second long lug of the symmetrical row of lugs, closest to the axially inner end face of the first long lug, by an end groove with a width at least equal to 10% and at most equal to 100% of the lug height.