Pneumatic Tyre Shoulder Rib Height Reduction Groove Cracking
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Solution Overview
Problem
Heavy-duty vehicle tires experience cracking at the base of circumferential grooves adjacent to shoulder ribs or rows due to high loads, and existing solutions to reduce this cracking, such as widening belt layers or adding special rubber layers, either compromise belt durability or are difficult to implement in series production.
Innovation Solution
The height of profile ribs or rows adjacent to shoulder ribs or blocks is reduced, with the lowest height in the circumferential groove on the shoulder side increasing continuously in the axial direction, thereby decreasing the load on the groove base and susceptibility to cracking without adverse effects on other profile properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the belt layers are widened to reduce cracking at the groove base, then the resistance to cracking is improved, but the belt durability deteriorates
Solution Approach 1:
The patent applies local quality by creating a shoulder rib with a reduced height zone specifically at the groove base area. This localized modification reduces stress concentration at the critical groove base location without affecting the overall belt layer dimensions, thereby preventing cracking while maintaining belt durability.
Solution Approach 2:
The patent changes the geometric parameter of the shoulder rib by reducing its height in the circumferential direction at the groove base area. This parameter change modifies the stress distribution pattern, reducing peak stresses at the groove base and preventing crack formation without requiring belt layer widening.
2Reliability
If special layers of rubber are introduced at the base of the grooves to reduce cracking, then the resistance to cracking is improved, but the manufacturing complexity increases
Solution Approach 1:
Instead of introducing special rubber layers, the patent applies local quality through a geometric modification of the shoulder rib. The reduced height zone is created directly in the existing rubber material, avoiding the need for additional layers or materials while achieving the same crack prevention effect.
Solution Approach 2:
The patent extracts the crack prevention function from the material composition (special rubber layers) and implements it through geometric form (reduced shoulder rib height). This simplifies the structure by removing the need for complex multi-layer constructions while maintaining the protective function.
3Force
If the profile rib height is reduced at the shoulder area, then the load at the groove base is decreased, but the tread wear characteristics may be affected
Solution Approach 1:
The patent applies local quality by reducing the shoulder rib height specifically in the circumferential direction at the groove base area, while maintaining the radial height and overall tread profile. This localized modification reduces load at the critical groove base location without significantly affecting the overall tread wear characteristics.
Solution Approach 2:
The patent applies partial action by reducing the shoulder rib height only in the specific region where cracking occurs (at the groove base), rather than reducing the entire shoulder rib. This selective modification minimizes the impact on tread wear performance while effectively reducing the load at the problematic area.
Data Source
Figure 1~2
AI summary
The vehicle pneumatic tire has a radial ply casing (1), a tire belt assembly (2) and a running strip (3) with five profile ribs or profile block rows rotating in circumferential direction. A running strip half has a profile rib running adjacent to a shoulder rib (6) or shoulder block row or block row over an axial extending of 75 percent of smaller height. The exterior surfaces of the other profile ribs or block rows are detected from a uniform envelope (9).