Passenger Tyre Tread Elastomer and Reinforcement Angles
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Solution Overview
Problem
Current passenger tires face challenges in achieving improved longitudinal and transverse grip on both wet and dry surfaces while maintaining performance levels at low transverse acceleration and wear resistance, with limitations in rolling resistance and noise reduction.
Innovation Solution
The tire design incorporates a tread with a modified diene elastomer containing a silicon atom in its main chain, a hooping reinforcement with aromatic polyamide textile reinforcements, and an intermediate elastomeric layer, along with specific angles and configurations of metal and textile reinforcements to enhance grip, wear resistance, and reduce rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tread uses conventional elastomeric mixtures with higher glass transition temperatures and hardness, then wear resistance is improved, but grip on wet and dry surfaces deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the glass transition temperature of the elastomeric mixture from conventional ranges (-5°C to -1°C) to a lower range (-18°C to -6°C). This parameter change allows the tread material to maintain softer, more compliant characteristics that improve grip on both wet and dry surfaces while the specific composition and reinforcement structure maintain adequate wear resistance.
Solution Approach 2:
The patent uses composite materials by combining the modified low glass transition temperature elastomeric mixture with specific reinforcement structures including aromatic polyamide textile reinforcements at optimized angles and metal cable reinforcements. This composite approach allows the softer elastomeric base to provide grip while the reinforcement structure maintains durability and wear resistance.
2Reliability
If the tire uses softer elastomeric mixtures with lower glass transition temperatures to improve grip, then rolling resistance increases, but fuel consumption increases
Solution Approach 1:
The patent employs composite materials by integrating the softer elastomeric mixture (with glass transition temperature of -18°C to -6°C) with a sophisticated reinforcement system comprising aromatic polyamide textile reinforcements and metal cable reinforcements. This composite structure allows the softer material to provide improved grip while the reinforcement framework reduces deformation and energy loss, thereby controlling rolling resistance despite the softer compound.
3Loss of energy
If the tire uses higher volumetric notch rates to reduce weight and improve fuel efficiency, then tread volume and grip surface area decrease
Solution Approach 1:
The patent applies parameter changes by optimizing the volumetric notch rate to a specific range (23% to 33%) rather than maximizing it. This optimized parameter allows sufficient tread volume to be maintained for adequate grip surface area and fuel efficiency, while the modified elastomeric mixture composition compensates for the reduced tread volume to ensure grip performance is not compromised.
4Strength
If the tire uses conventional metal reinforcement angles to maintain structural integrity, then longitudinal and transverse grip are limited
Solution Approach 1:
The patent applies parameter changes by optimizing the angle of metal cable reinforcements relative to the circumferential direction, setting it within a specific range (20° to 30°). This optimized angle provides an ideal balance between maintaining structural integrity for structural strength and achieving enhanced longitudinal and transverse grip through improved force distribution during acceleration, braking, and cornering.
Data Source
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AI summary
The invention relates to a tyre (1) for a private passenger vehicle and is intended to improve longitudinal and lateral wet and dry grip relative to the reference prior art, while maintaining the same performance levels in terms of behaviour, in particular at low lateral acceleration, and wear. According to the invention, the volume grooving rate of the tread (2) is at least equal to 20% and at most equal to 29% and the radial height (Hs) of the raised elements (22) of the tread (2) is at least equal to 6.0 mm and at most equal to 7.6 mm. The elastomer blend used for the tread (2) has a glass transition (GT) temperature that is at least equal to - 18°C and at most equal to -6°C, a Shore hardness A that is at least equal to 60 and at most equal to 75, and a loss at 60°C that is at least equal 24% and at most equal to 35%, and comprises a modified diene elastomer containing at least one functional group comprising a silicon atom, the latter being located within the backbone of the elastomer including the chain ends. The textile reinforcements of the hooping ply (31) of the hooping reinforcement (3) comprise an aromatic polyamide, such as aramid, and the metal reinforcements of each of the working plies (41, 42) of the working reinforcement (4) form an angle (AT1, AT2) with the circumferential direction XX' of the tyre having an absolute value that is at least equal to 25° and at most equal to 40°.