Rubber Track Core End Covering Thickness for Crack Resistance
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Solution Overview
Problem
Existing rubber tracks with short-pitch cores and lugs are prone to edge-cutting cracks due to uneven rigidity and stress concentration at the end portions of the cores, which are not adequately covered by the rubber elastic body, especially when encountering obstacles like curbstones.
Innovation Solution
The rubber track design features a gradual decrease in core thickness towards the end edge, with increased rubber covering thickness between lugs on both inner and outer surfaces, forming flat surfaces to distribute strain and prevent stress concentration, and positioning the steel cord reinforcing layer inside the core's end position to reduce external stress impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lugs are arranged on the outer peripheral surface of the rubber track to improve cut resistance and vibration reducing property, then the traction performance is improved, but the covering thickness at the end portion of the core becomes thinner, leading to stress concentration and crack occurrence
Solution Approach 1:
The patent applies local quality by forming a thicker rubber covering specifically at the end portions of the cores where cracks are most likely to occur. This localized thickness variation ensures that the critical areas have enhanced protection without compromising the overall lug structure for traction.
Solution Approach 2:
The patent implements beforehand cushioning by pre-forming a thicker rubber covering at the vulnerable end portions of the cores before the track encounters obstacles. This preventive measure distributes strain and prevents stress concentration that would otherwise lead to edge-cutting cracks during operation.
2Reliability
If a ridge is formed on the outer peripheral surface at the end portions of the core to disperse strain, then crack occurrence is prevented, but the rubber covering thickness becomes significantly small, and spurs are formed that are likely to be caught by curbstones, promoting crack occurrence
Solution Approach 1:
The patent applies local quality by selectively increasing the rubber covering thickness only at the end portions of the cores where cracks are most likely to occur, rather than uniformly thickening the entire track. This localized approach prevents stress concentration without creating protruding spurs that would catch on curbstones.
Solution Approach 2:
Instead of forming a ridge that protrudes outward and creates spurs (as in conventional designs), the patent inverts the approach by forming a thicker covering that blends smoothly with the surrounding rubber surface. This eliminates the spur problem while still providing strain distribution and crack prevention.
3Reliability
If the wall thickness of the rubber body portion at the end portion of the rubber track is made substantially equal in all directions, then stress concentration is reduced and durability improves, but the thickness of rubber on the lug side is insufficient to prevent cracks at the core end
Solution Approach 1:
The patent applies local quality by creating a non-uniform thickness distribution specifically at the end portions of the cores, where the rubber covering is made thicker than in other areas. This localized thickening provides enhanced protection at the most vulnerable points without compromising the overall structural balance of the track.
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 configuration effectively suppresses crack formation by distributing strain and reducing stress concentration, enhancing durability and traction performance while maintaining even rubber thickness for improved resistance to external damage.
Implementation Method 1
a covering thickness of the rubber elastic body at a portion between lugs on each of the inner peripheral surface side and the outer peripheral surface side is formed thicker than a covering thickness of the rubber elastic body at a point located 1/4 of the core length from the end edge position of the core
Implementation Method 2
the covering surfaces on both the inner peripheral surface side and the outer peripheral surface side are formed into flat surfaces... effectively suppresses crack formation by distributing strain and reducing stress concentration
Implementation Method 3
the covering surfaces on both the inner peripheral surface side and the outer peripheral surface side are formed into flat surfaces... enhancing durability and traction performance while maintaining even rubber thickness for improved resistance to external damage
Data Source
AI summary
An endless rubber elastic body 1; a plurality of cores 2 arranged at predetermined pitches and extending in a width direction of the rubber elastic body; a steel cord reinforcing layer surrounding the cores; and a lug 4 formed on an outer peripheral surface of the rubber elastic body 1 at predetermined intervals. Thicknesses of respective end portions of each core 2 are gradually decreased or made constant toward respective end edges. A covering thickness t1, t2 of rubber elastic body 1 is thicker at a portion between lugs on each of an inner and outer peripheral surface side than covering thickness T1, T2 of the rubber elastic body. Covering surfaces on both inner and outer peripheral surface sides are flat.