Pneumatic Tire Sipe Layout for Wet Braking and Mold Release
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Solution Overview
Problem
Pneumatic tires face challenges in maintaining braking performance on wet and icy surfaces while avoiding poor appearance issues during vulcanization molding, as existing methods either compromise sipe density or length, leading to suboptimal performance and aesthetic changes.
Innovation Solution
A pneumatic tire design featuring a tread portion with a segmented structure, where the ratio of three-dimensional sipes in the boundary regions is reduced to prevent mold bonding, while maintaining sufficient three-dimensional sipes across the tire for enhanced wet and snow performance without altering the tire's appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the number of sipes and the length of sipes are reduced in the vicinity of sector dividing position, then bonding between tire mold and tread rubber is suppressed, but wet performance and snow performance deteriorate
Solution Approach 1:
The patent applies local quality by differentiating sipe configurations between boundary regions (near sector dividing positions) and non-boundary regions. In boundary regions, the number and length of sipes are reduced to prevent mold bonding, while in non-boundary regions, full sipe density and length are maintained to ensure optimal wet and snow performance. This localized differentiation resolves the contradiction by allowing region-specific optimization.
Solution Approach 2:
The tread portion is segmented into multiple land portions, each independently configured with appropriate sipe arrangements. This segmentation allows each land portion to be optimized for its specific function - boundary land portions prioritize mold release while non-boundary land portions prioritize traction performance, thereby resolving the performance contradiction through functional segmentation.
2Object-generated harmful factors
If the number of sipes and the length of sipes are reduced in the vicinity of sector dividing position, then bonding between tire mold and tread rubber is suppressed, but the appearance of tire changes
Solution Approach 1:
The invention applies local quality by restricting sipe reduction to only those land portions located in boundary regions near sector dividing positions. Land portions in non-boundary regions maintain their original sipe configurations, preserving the uniform and aesthetically pleasing appearance of the tire while still preventing mold bonding in the critical boundary regions where it occurs.
3Reliability
If three-dimensional sipes are used throughout the tread portion, then wet performance and snow performance are enhanced, but bonding between tire mold and tread rubber increases
Solution Approach 1:
The patent applies local quality by using different sipe types in different regions: three-dimensional sipes are deployed in non-boundary land portions to maximize wet and snow performance, while two-dimensional sipes are used in boundary land portions where they provide sufficient performance while reducing mold bonding. This localized differentiation resolves the contradiction by matching sipe characteristics to regional requirements.
Solution Approach 2:
The tread is segmented into boundary and non-boundary land portions, with each segment using appropriately configured sipes. This segmentation allows the tire to achieve high overall performance by concentrating three-dimensional sipes in performance-critical non-boundary regions while using simpler two-dimensional sipes in boundary regions where mold bonding is the primary concern.
Data Source
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AI summary
Provided is a pneumatic tire that allows enhancing braking performance on wet road surfaces and snowy road surfaces and reducing the occurrence of poor appearance, without changing the appearance of a tire. In the pneumatic tire, a tread portion including a plurality of rows of land portions defined by a plurality of circumferential grooves extending in a tire circumferential direction is formed by a plurality of sectors divided in the tire circumferential direction, a plurality of sipes extending in a tire width direction formed in the land portions include a three-dimensional sipe, whose shape appearing on a tread surface changes along a sipe depth direction, and a two-dimensional sipe, whose shape appearing on the tread surface is constant along the sipe depth direction, and a ratio R1 of the number of the three-dimensional sipes with respect to the total number of the sipes in the first boundary region, which is within 15 mm on one side of a sector dividing position in the tire circumferential direction, and a ratio Rt of the number of the three-dimensional sipes with respect to the total number of the sipes in all of the tread portion satisfy the relationship R1 < Rt.