Pneumatic Tire Rib Projection Contact Rigidity
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Solution Overview
Problem
Pneumatic tires with rib patterns face significant compressive deformation and heat generation due to grounding, leading to increased rolling resistance, as existing solutions like projection portions only enhance rigidity at tread transverse ends and not across the entire tread.
Innovation Solution
The tire features elongate projection portions that project toward each other from adjacent rib-shaped land portions, forming an annular shape in the tread circumferential direction, with communication recesses between them to maintain drainage and support each other upon grounding, reducing elastic deformation and rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If projection portions are formed only at tread transverse ends, then cornering power is enhanced, but rigidity of rib-shaped land portions across the entire tread cannot be maintained
Solution Approach 1:
The projection portions are segmented into multiple circumferential grooves across the tread width, with each groove containing projection portions from adjacent rib-shaped land portions. This segmentation allows rigidity enhancement to be distributed across the entire tread rather than concentrated only at the ends, while still maintaining cornering power through the end grooves.
Solution Approach 2:
The projection portions are configured with different local characteristics: grooves at the tread transverse ends have projection portions that enhance cornering power, while grooves in the central tread region have projection portions that primarily enhance rigidity. This local differentiation allows simultaneous optimization of both cornering power and overall rigidity.
2Ease of manufacture
If projection portions are disposed at large intervals, then manufacturing is simplified, but rigidity of rib-shaped land portions over the whole tread cannot be maintained
Solution Approach 1:
The projection portions extend in the tread width direction (lateral dimension) rather than only in the tread circumferential direction. This dimensional change allows the projection portions to span across multiple grooves and provide continuous rigidity support across the tread width, even when spaced at larger intervals in the circumferential direction.
Solution Approach 2:
Adjacent projection portions from different rib-shaped land portions are merged through elastic deformation to form a continuous support structure across the groove. This merging effect creates a unified rigid structure that spans the groove width, maintaining rigidity even with larger circumferential spacing between projection portions.
3Reliability
If circumferential grooves are provided to enhance draining, then wet grip performance is improved, but elastic deformation of rib-shaped land portions increases leading to higher rolling resistance
Solution Approach 1:
The projection portions are pre-configured to make contact and provide mutual support before significant elastic deformation occurs during grounding. This preliminary support action prevents excessive deformation of the rib-shaped land portions, reducing hysteresis loss and rolling resistance while maintaining the circumferential grooves for drainage and wet grip performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the rigidity of rib-shaped land portions across the entire tread, effectively reduces rolling resistance, and maintains good wet grip performance by ensuring proper drainage through communication recesses.
Implementation Method 1
mutually confronting tip surfaces of the confronting elongate projection portions are adapted to be in contact with each other through elastic deformation of the rib-shaped land portions at a time of grounding of the tire
Implementation Method 2
the mutually confronting tip surfaces of the confronting elongate projection portions are formed with a plurality of communication recesses providing communication between an outside groove space and an inside groove space
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A pneumatic tire has a tread having adjacent rib-shaped land portions (4) with circumferential grooves (3) therbetween. Annular elongate projection portions (5, 5) project toward each other from adjacent rib-shaped land portions (4). The elongate projection portions (5, 5) confronting each other are disposed with a spacing therebetween such that their mutually confronting tip surfaces (5s, 5s) make contact with each other due to elastic deformation of the rib-shaped land portions (4, 4) at the time of grounding of the tire. An inside groove space (6) is formed on a radially inner side of the confronting elongate projection portions (5, 5) and an outside groove space (7) is formed on a radially outer side of the elongate projection portions (5, 5). The tip surfaces (5s) of the elongate projection portions (5) are formed with a plurality of communication recesses (9) providing communication between the inside and outside groove spaces (6, 7). The communication recesses (9) are formed at intervals in a tread circumferential direction. It is thus possible to enhance rigidity of the rib-shaped land portions over the whole tread at the time of grounding of the tire, thereby to suppress elastic deformation of the rib-shaped land portions and to reduce rolling resistance, while securing a draining property attributable to the circumferential grooves.