Tire Bead Grooves for Air Occlusion Drainage
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Solution Overview
Problem
Heavy goods vehicle tires with carcass reinforcement cords of low or zero permeability face air occlusion issues during manufacturing, leading to reduced endurance performance due to air concentration in channels, which can weaken the metal assemblies and affect tire fatigue.
Innovation Solution
The method involves forming grooves on the bead rubber strip and filler strip surfaces to allow air occlusion to be drained and dispersed, ensuring a large area for air distribution without compromising adhesion between the strips, thereby preventing air from accumulating in the carcass reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cords of low or zero permeability are used to reinforce the carcass, then air tightness is improved, but air occlusion during manufacturing leads to reduced endurance performance
Solution Approach 1:
The bead rubber strip is segmented by creating grooves that divide it into multiple sections. These grooves create air channels that allow occluded air to escape during manufacturing while maintaining the overall structural integrity of the bead assembly
Solution Approach 2:
The grooves act as intermediary channels between the occluded air and the external environment. They provide a controlled pathway for air to escape without compromising the airtightness provided by the low-permeability cords, thus mediating between the conflicting requirements
2Strength
If the bead rubber strip is made solid without grooves, then adhesion between strips is improved, but air occlusion concentrates in channels within the carcass reinforcement
Solution Approach 1:
The bead rubber strip has different local qualities: solid regions provide adhesion and structural support, while grooved regions provide air escape pathways. This local differentiation allows the structure to simultaneously achieve strong adhesion and effective air drainage
3Object-generated harmful factors
If grooves are created in the bead rubber strip, then air drainage is improved, but adhesion area between strips is reduced
Solution Approach 1:
The grooves are designed to extend only partially through the thickness of the bead rubber strip, not completely through it. This partial action provides sufficient air drainage pathways while preserving enough solid material to maintain adequate adhesion between strips
Data Source
AI summary
Method of manufacturing a tire comprising a carcass reinforcement extending between beads, this carcass reinforcement being anchored in each bead by being wrapped around each circumferential bead reinforcement to form a turned-back portion, this carcass reinforcement comprising at least one rubber ply which is reinforced with a plurality of metal cords of low or zero permeability, each bead comprising a plurality of rubber-based strips, at least one of these strips, known as the bead rubber strip, radially on the outside of the circumferential bead reinforcement performing a function of filling and mechanical connection between the carcass reinforcement and its turned-back portion, this bead rubber strip comprising a first surface axially towards the inside in contact with the carcass reinforcement and a second surface axially towards the outside, each bead further comprising at least one other strip, known as the filler strip which, radially on the outside of the radially outermost points of the turned-back portion of the carcass reinforcement is at least partly in contact with part of the second surface of the bead rubber strip to form a region of contact between the said two profiled elements this method comprising a step of forming a plurality of grooves on at least one of the surfaces of the strips that are in contact in the contact region, these grooves being distant from one another by at least a distance equal to 5 mm, and these first surface of the bead rubber strip being completely devoid of any groove.