Pneumatic Tire Sipe Protrusions for Demolding
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Solution Overview
Problem
The demolding behavior of pneumatic vehicle tires with three-dimensional incisions featuring projections and depressions is problematic, leading to tears, flaking, and adhesion issues during vulcanization, which affects the tire's rigidity and driving characteristics, especially under winter conditions.
Innovation Solution
Designing incisions with projections and depressions only on the main section for maximum depth, ensuring double-symmetrical stability, and keeping edge sections unstructured to reduce demolding forces, along with specific geometric configurations for projections and depressions to enhance tread stability and demolding ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If projections and depressions are added to incision walls to improve tread stiffness and driving characteristics, then traction and stability are improved, but demolding becomes difficult causing tears and flaking
Solution Approach 1:
The patent applies different structural characteristics to different parts of the incision: the main section has projections and depressions for stiffness, while the edge sections have smooth walls for easy demolding. This local differentiation resolves the contradiction between needing structural complexity for performance and simplicity for manufacturing.
Solution Approach 2:
The incision is divided into functionally distinct segments: a main section with projections/depressions for mechanical performance and edge sections with smooth surfaces for demolding. This segmentation allows each part to optimize its function without compromising the other.
2Stability of the object's composition
If zigzag-shaped incisions are used to improve tread stability, then driving characteristics are improved, but demolding forces increase causing adhesion issues
Solution Approach 1:
The zigzag shape is applied locally to the main section of the incision where it provides stability benefits, while the edge sections maintain smooth walls. This allows the tread stability advantage to be retained without the full demolding penalty of a complete zigzag design.
3Manufacturing precision
If narrow incisions are used to improve tread precision, then manufacturing precision is improved, but demolding becomes more problematic due to adhesion
Solution Approach 1:
The narrow incision design is maintained in the main section for precision, while the edge sections have slightly wider smooth walls that facilitate demolding. This local variation preserves the precision benefits while reducing demolding adhesion problems.
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a pneumatic vehicle tire, comprising a tread having profile elements (1), for example tread lugs (1), which profile elements are separated from one another by grooves (2, 3) and are each provided with a plurality of sipes (4), which run at an angle of up to 45° to the axial direction and parallel to one another and have a constant width (B), a maximum sipe depth (T) and two sipe walls (5, 6). The sipes (4) are composed of a main portion (4a) reaching to the maximum sipe depth (T) or of such a main portion (4a) and at least one shallower edge portion (4b). In a top view of the sipe (4), the main portion (4a) comprises at least one shorter portion (4"a) and at least one portion (4'a) longer than the at least one shorter portion. The portions (4'a, 4"a) include an angle (a) of 90° to 140° with one another. In the longer portion (4'a), at least one recess (9) is formed in the one sipe wall (5), and a protrusion corresponding to the recess (9) lies opposite the recess on the other sipe wall (6). The protrusion (10) and the recess (9) are elongate in the direction of extent of the sipe (4). In the longer portion (4'a) or in each longer portion (4'a) of the main portion (4a), exactly one recess (9) which is mirror-symmetrical with respect to a cross-section center plane (E2) that is perpendicular to the sipe wall (5) and that runs in the radial direction and with respect to a longitudinal-section center plane (E1) that runs orthogonally to said cross-section center plane is formed in the one sipe wall (5). Any edge portions (4b) of the sipe (4) are free of protrusions (10) and recesses (9).