Pneumatic Tire Protrusion Design for Rubber Flow Control
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Solution Overview
Problem
During vulcanization molding of pneumatic tires with protrusions, defective rubber flow can occur, leading to bareness on the tire surface, which affects the tire's appearance quality.
Innovation Solution
The design includes a protrusion on the groove bottom surface with a raised portion that increases in height from the outside to the inside, featuring vent marks for air discharge and step portions to guide rubber flow effectively, reducing bareness and maintaining appearance quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protrusions are provided on groove bottoms of the pneumatic tire, then stone ejector function is improved, but defective rubber flow occurs in recesses of the mold during vulcanization molding
Solution Approach 1:
The protrusion is divided into multiple sections: a main body portion and a raised portion with different height characteristics. The raised portion has a height that increases from outside to inside, creating a gradient structure that guides rubber flow while the main body provides the stone ejector function. This segmentation allows each portion to serve its specific purpose without interfering with the other.
Solution Approach 2:
Different portions of the protrusion have different height characteristics tailored to their specific functions. The raised portion has increasing height from outside to inside to guide rubber flow into the recess, while the main body maintains a specific height for stone ejection. This local differentiation of quality optimizes both functions simultaneously.
2Shape
If the recess of the mold is made deeper to form the protrusion, then the protrusion shape is improved, but rubber flow becomes defective and bareness is produced
Solution Approach 1:
The raised portion with its gradient height structure is designed in advance to guide rubber flow before the rubber enters the deep recess. This preliminary guiding action ensures that rubber flows smoothly into the recess area, preventing defective flow and bareness while still allowing the recess to be deep enough to form the desired protrusion shape.
Solution Approach 2:
The raised portion acts as an intermediary structure between the shallow mold surface and the deep recess. It provides a gradual transition path for rubber flow, mediating between the conflicting requirements of deep recess for shape formation and smooth rubber flow for surface quality.
3Reliability
If vents are added to discharge air during vulcanization molding, then air discharge function is improved, but vent marks are produced on the tire surface
Solution Approach 1:
Vents are strategically placed only in specific locations where they are least visible, such as on the inner sidewall or in areas that will not be prominently displayed. This localized placement maintains air discharge function while minimizing the visual impact of vent marks on the tire's appearance quality.
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 ensures proper rubber flow and air discharge, minimizing bareness and enhancing the external appearance of the tire by guiding rubber to the deepest recess and discharging air effectively through vents.
Implementation Method 1
The vent mark is formed on the raised portion of the protrusion as a mark of the vent on the tire vulcanization mold. Accordingly, air is discharged to the outside of the tire vulcanization mold through the vent in the portion of the recess corresponding to the raised portion of the protrusion during vulcanization molding.
Implementation Method 2
the raised portion of the protrusion is shaped such that the height of the raised portion from the groove bottom surface increases from the outside to the inside in the longitudinal direction of the main body. Accordingly, the recess of the tire vulcanization mold corresponding to the protrusion becomes deeper from the outside to the inside in the longitudinal direction of the recess in the portion corresponding to the raised portion of the protrusion. In this case, rubber is guided along the portion of the recess corresponding to the raised portion of the protrusion during vulcanization molding.
Data Source
AI summary
A pneumatic tire includes: a lateral groove that includes a groove bottom surface extending in a direction crossing a tire circumferential direction; and a protrusion provided on the groove bottom surface and extending in an extension direction of the groove bottom surface. The protrusion includes: a main body; and a raised portion provided at least at one end portion on one side in a longitudinal direction of the main body, and shaped such that a height of the raised portion from the groove bottom surface increases from an outside to an inside in the longitudinal direction of the main body. The raised portion has at least one vent mark that is a mark of a vent of a tire vulcanization mold.