Tire Insertion Layer for Conductivity and Stability
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Solution Overview
Problem
Tires with low-heat-generation properties to reduce rolling resistance may compromise electric conductivity and steering stability due to the removal or reduction of the tie gum layer, which affects the carcass's ability to function as a conductive path.
Innovation Solution
Incorporating insertion layers between the carcass and the inner liner with a volume resistivity less than 108 Ω·cm and a complex elastic modulus equivalent to or higher than the inner liner, ensuring the carcass can maintain conductivity and stability while reducing rolling resistance by eliminating the need for a tie gum layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the tie gum layer is removed or reduced to reduce the thickness of the side portion, then rolling resistance is reduced, but electric conductivity is compromised and steering stability is degraded
Solution Approach 1:
The invention introduces an insertion layer as an intermediary component between the inner liner and the carcass/topping rubber. This insertion layer has low volume resistivity (less than 10^8 Ω·cm) and acts as a conductive path, replacing the conductive function that would otherwise be provided by a thick tie gum layer. The insertion layer enables electric conductivity to be maintained while allowing the side portion thickness to be reduced, thus resolving the contradiction between reducing rolling resistance and maintaining electric conductivity.
2Loss of energy
If the tie gum layer is removed or reduced to reduce the thickness of the side portion, then rolling resistance is reduced, but steering stability is degraded
Solution Approach 1:
The insertion layer serves as a mediator that maintains the structural integrity and functional performance of the tire. By providing both conductive properties and appropriate mechanical properties (complex elastic modulus equivalent to or higher than the inner liner), the insertion layer ensures that steering stability is maintained even when the side portion thickness is reduced, thus resolving the contradiction between reducing rolling resistance and maintaining steering stability.
Solution Approach 2:
The invention changes the key parameters of the insertion layer (volume resistivity less than 10^8 Ω·cm and complex elastic modulus equivalent to or higher than the inner liner) to achieve the desired balance. By carefully controlling these parameters, the insertion layer can provide both electrical conductivity and mechanical support, enabling reduced side portion thickness without compromising steering stability.
3Loss of energy
If rubber having low-heat-generation properties is used to reduce rolling resistance, then rolling resistance is reduced, but electric conductivity is compromised due to accumulation of static electricity
Solution Approach 1:
The insertion layer acts as a conductive intermediary that compensates for the loss of electric conductivity caused by using low-heat-generation rubber. The low volume resistivity of the insertion layer (less than 10^8 Ω·cm) ensures that static electricity can be dissipated effectively, maintaining electric conductivity even when the main rubber compound has low-heat-generation properties. This resolves the contradiction between reducing rolling resistance through low-heat-generation rubber and maintaining electric conductivity.
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 effectively reduces rolling resistance while maintaining electric conductivity and steering stability, ensuring the carcass functions as a conductive path without compromising the tire's structural integrity.
Implementation Method 1
The insertion layers are each disposed between an end of the belt and an end of a corresponding one of the beads. The insertion layers each have a volume resistivity of less than 108 Ω·cm.
Implementation Method 2
A complex elastic modulus of each insertion layer is equivalent to or higher than a complex elastic modulus of the inner liner.
Data Source
AI summary
A tire 2 includes a tread 4, a pair of sidewalls 6, a pair of beads 10, a carcass 12, a belt 14, an inner liner 20, and a pair of insertion layers 22 disposed between the carcass 12 and the inner liner 20. Each insertion layer 22 is disposed between an end of the belt 14 and an end PB of the bead 10. Each insertion layer 22 has a volume resistivity of less than 108 Ω·cm. A complex elastic modulus of the insertion layer 22 is equivalent to or higher than a complex elastic modulus of the inner liner 20. A thickness of each sidewall 6 at a maximum width position PW is not greater than 5.0 mm.