Commercial Vehicle Tyre Squeegee Layer Filler Content
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Solution Overview
Problem
Commercial vehicle tires with squeegee layers face challenges in reducing rolling resistance without compromising durability and retreadability, as existing squeegee mixtures with high filler content lead to mechanical issues and increased rolling resistance.
Innovation Solution
A squeegee layer with a reduced filler content of carbon black and/or silica, ranging from 20 phr to less than 35 phr, and a variable thickness distribution, being thicker in shoulder areas to prevent creep and flow, while maintaining low rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a squeegee layer with high filler content (carbon black and/or silica exceeding 50 phr) is used, then mechanical tensile strength and low creep or flow resistance are improved, but rolling resistance increases
Solution Approach 1:
The patent changes the filler content parameter from the conventional >50 phr to a reduced range of 20-35 phr, which directly reduces rolling resistance by 1.5-2% while maintaining adequate mechanical properties through optimized compound formulation
2Reliability
If the squeegee layer thickness is increased in shoulder areas to prevent creep and flow, then durability is improved, but rolling resistance increases
Solution Approach 1:
The patent applies local quality by varying the squeegee layer thickness across different tire regions - thicker in shoulder areas (at least 25% greater than arithmetic mean) to prevent creep and flow, while maintaining reduced overall filler content to keep rolling resistance low
3Strength
If natural rubber with high proportion is used in the squeegee layer compound, then steel cord adhesion is improved, but rolling resistance increases
Solution Approach 1:
The patent reduces the filler content parameter to 20-35 phr (down from conventional >50 phr), which decreases rolling resistance while maintaining natural rubber content for adequate adhesion, achieving a balance between mechanical performance and energy efficiency
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 solution results in a 1.5% to 2% lower rolling resistance compared to tires with standard squeegee layers, without adverse effects on durability or retreadability, and surprisingly does not increase rolling resistance despite the increased thickness in critical areas.
Implementation Method 1
the squeegee layer acts as a protective layer within the tire, preventing the inner layer compound from penetrating the spaces between the carcass cords of the ply or coming into contact with them during flow or creep processes occurring during tire manufacturing and vulcanization
Implementation Method 2
Studies on commercial vehicle tires, especially tires for trucks or buses, have shown that tires whose squeegee layer is based on a rubber compound with a filler content of less than 35 phr have a 1.5% to 2% lower rolling resistance than commercial vehicle tires whose squeegee layer is based on a rubber compound with a filler content of approximately 50 phr to 55 phr
Data Source
Figure 1
AI summary
A radial commercial vehicle tire comprising a tread, a belt assembly (3) with several belt plies (3a), an airtight inner layer (8) facing the inside of the tire, a carcass ply (4) with carcass cords running radially or substantially radially, and a squeegee layer (1) located between the carcass ply (4) and the inner layer (8), which is based on a rubber compound containing carbon black and/or silica as filler. The squeegee layer (1) is based on a rubber compound whose carbon black and/or silica filler content is between 20 phr and less than 43 phr.