Tire Bead Rubber Layer Structure for Heavy-Load Durability
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Solution Overview
Problem
There is a need to further enhance the durability performance of pneumatic tire bead portions, particularly for small trucks that are subjected to heavy loads, as existing designs do not adequately address rigidity and durability issues.
Innovation Solution
The pneumatic tire incorporates a reinforcing rubber portion with an axially inner rubber layer and an axially outer rubber layer positioned adjacent to each other, where the radially outer end of the outer layer is outside the inner layer's end and the radially inner end of the outer layer is inside the inner layer's end, enhancing lateral rigidity and suppressing deflection and strain concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer rubber structure is used in the bead portion, then the structure is simple and easy to manufacture, but the lateral rigidity is insufficient and bead durability is poor under heavy loads
Solution Approach 1:
The rubber layer in the bead portion is segmented into two distinct layers: an axially inner rubber layer and an axially outer rubber layer. This segmentation allows each layer to perform different functions - the inner layer provides base structural support while the outer layer enhances lateral rigidity, thereby improving bead durability without creating an overly complex monolithic structure.
Solution Approach 2:
The axially outer rubber layer is positioned specifically at the radially outer side of the axially inner rubber layer, creating a local quality enhancement in the bead portion. This localized structural modification targets the specific area where lateral rigidity is needed most, improving bead durability precisely where heavy loads are applied during vehicle operation.
2Strength
If the rubber layers are positioned with overlapping radial ends, then lateral rigidity is maximized, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter relationships between the two rubber layers: the radially outer end of the axially outer rubber layer is positioned radially outside the radially outer end of the axially inner rubber layer, and the radially inner end of the axially outer rubber layer is positioned radially inside the radially inner end of the axially inner rubber layer. These parameter definitions provide clear manufacturing guidelines that balance rigidity requirements with manufacturability.
Data Source
AI summary
A pneumatic tire 1 has a bead portion provided with a reinforcing rubber portion disposed adjacently to the axially outer side of a carcass. The reinforcing rubber portion comprises an axially inner rubber layer and an axially outer rubber layer. The radially outer end of the axially outer rubber layer is positioned radially outside the radially outer end of the axially inner rubber layer. The radially inner end of the axially outer rubber layer is positioned radially inside the radially inner end of the axially inner rubber layer.