Pneumatic Tire Conductive Portion Arc-Shaped Profile
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Solution Overview
Problem
Tires with silica-rich rubber treads tend to accumulate static electricity due to high electric resistance, and the conductive portions used to discharge static electricity often deform during vulcanization, leading to rubber separation issues.
Innovation Solution
A pneumatic tire design featuring a conductive portion made of conductive rubber that extends from the inner end to the outer end with an inclination, where the outer end is positioned on the central axis or towards the first edge of the land portion, and a tire mold with an arc-shaped ground contact surface to maintain the conductive portion's angle and prevent deformation during vulcanization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive portion is provided to discharge static electricity from silica-rich rubber tires, then static electricity discharge is improved, but rubber separation occurs at the outer end of the conductive portion
Solution Approach 1:
The patent applies local quality by creating a specific ground contact surface profile with an arc-shaped protrusion at the location where the conductive portion exits. This localized structural modification concentrates the rubber material and creates enhanced adhesion precisely at the critical outer end region, preventing separation while maintaining the conductive portion's electricity discharge function throughout its length
Solution Approach 2:
The patent employs curvature by designing the ground contact surface with an arc-shaped profile that protrudes radially outwardly. This curved geometry redistributes the rubber material and creates a more favorable stress distribution at the conductive portion interface, preventing the sharp stress concentration that leads to separation. The arc shape allows the conductive portion to exit at an optimized angle while maintaining strong adhesion
2Reliability
If the conductive portion extends with an inclination to discharge static electricity, then electricity discharge function is improved, but the conductive portion deforms during vulcanization causing angle sharpening
Solution Approach 1:
The patent applies preliminary action by pre-forming the ground contact surface with an arc-shaped protrusion in the mold before vulcanization. This pre-configured geometric feature guides the conductive portion during the vulcanization process, ensuring it maintains the correct inclination angle and preventing deformation. The preliminary structural preparation in the mold compensates for the plasticizing effects that would otherwise cause angle sharpening
Solution Approach 2:
The patent utilizes parameter changes by modifying the ground contact surface geometry with a specific arc-shaped profile having controlled dimensions (radius of curvature 350-750mm, height 0.4%-0.8% of axial width). This geometric parameter modification creates a physical constraint that maintains the conductive portion's inclination angle during vulcanization, counteracting the material's tendency to deform under heat and pressure
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
The design effectively suppresses separation of the conductive portion and maintains a sufficient angle with the ground contact surface, ensuring durability and efficient static electricity discharge while preventing rubber separation.
Implementation Method 1
conductive portion made of conductive rubber... to be electrically connected to a rim... for discharging static electricity
Implementation Method 2
a land portion of the tread rubber defined by a pair of main grooves tends to be being plasticized such that a central region thereof flows axially outwardly toward the pair of main grooves
Data Source
AI summary
A pneumatic tire includes a tread portion including main grooves and land portions. In a cross-sectional view of the tire, one of the land portions includes a first edge, a second edge, a ground contact surface extending between the first edge and the second edge and having an arc-shaped profile protruding radially outwardly, and conductive portion made of conductive rubber. The conductive portion extends from a radially inner end to a radially outer end exposed at the ground contact surface with an inclination toward the first edge. The inner end is connected to a tire internal structural member to be electrically connected to a rim when the tire is mounted on the rim. On the ground contact surface, a central position of the outer end is located on a central position of the land portion in a tire axial direction, or on a side of the first edge.