Pneumatic Tyre Tread Block Stiffness Uniformity
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Solution Overview
Problem
The varying circumferential stiffness of tread blocks in pneumatic vehicle tires due to different circumferential lengths leads to irregular winter properties and abrasion, particularly affecting winter grip on snow and ice.
Innovation Solution
Incorporating a central incision with radial sliding surfaces in longer tread blocks, where the proportion of sliding surfaces in the total cutting area is adjusted based on the pitch length ratio to equalize circumferential stiffness across the row of blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tread blocks with different circumferential lengths are used to vary incision density, then winter grip is improved, but circumferential stiffness becomes non-uniform causing irregular abrasion
Solution Approach 1:
The patent applies local quality by introducing flat sliding surfaces specifically in the central region of incisions in longer tread blocks, while keeping other incisions with wave-shaped courses unchanged. This localized modification selectively reduces circumferential stiffness only where needed in longer blocks, maintaining the beneficial variation in incision density for winter grip while correcting the stiffness non-uniformity that causes irregular abrasion.
Solution Approach 2:
The patent changes the geometric parameter of the incision structure by introducing flat sliding surfaces with specific proportions (8-55% of total cutting area) in longer tread blocks. This parameter change directly modifies the circumferential stiffness characteristic, allowing the longer blocks to have reduced stiffness to match the uniformity requirement while preserving the different circumferential lengths that provide varied incision density for improved winter grip.
2Reliability
If more incisions are arranged in tread blocks with larger circumferential length, then winter properties are improved, but circumferential stiffness increases negatively affecting performance
Solution Approach 1:
The patent applies local quality by introducing flat sliding surfaces specifically in the central region of incisions in longer tread blocks, while keeping other incisions with wave-shaped courses unchanged. This localized modification selectively reduces circumferential stiffness only where needed in longer blocks, maintaining the beneficial variation in incision density for winter grip while correcting the stiffness non-uniformity that causes irregular abrasion.
Solution Approach 2:
The patent changes the geometric parameter of the incision structure by introducing flat sliding surfaces with specific proportions (8-55% of total cutting area) in longer tread blocks. This parameter change directly modifies the circumferential stiffness characteristic, allowing the longer blocks to have reduced stiffness to match the uniformity requirement while preserving the different circumferential lengths that provide varied incision density for improved winter grip.
Data Source
Figure 1~2
AI summary
Pneumatic vehicle tyre for passenger cars, in particular for use in winter driving conditions, having a tread profile with at least one centre block row (1) which runs around in the circumferential direction and whose profile blocks (2) are each provided with at least three sipes (5, 5´) which have a short width and run substantially parallel to one another and substantially in the transverse direction of the tread and which have in plan view a wave-shaped or a zig-zag profile, at least in certain sections, wherein the profile blocks (2) are arranged within pitches (P1, P2) of the same type which are provided in at least two differential circumferential lengths (LP1, LP2), wherein the profile blocks (2) have, in accordance with the pitch lengths (L1, L2), at least two differential circumferential lengths (LP1, LP2) within a range from 30 mm to 50 mm. The profile blocks (2) in pitches (P2) which are longer than the shortest pitch (P1) each have at least one central sipe (5´) which has, at the sipe base, a section (5´b) which extends in the radial direction and which is bounded by planar sliding faces (G), wherein the portion of the sliding faces (G) in the overall sectional face (F) of the sipe (5´) depends on the selected pitch length ratio, and is larger given relatively large pitch length ratios, wherein the zig-zag shape or wave shape extends to the sipe base in the other sipes in the profile block (2).