Segmented Tire Mold With Plate-Spring Tread Release
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Solution Overview
Problem
Conventional tire molds with projections on the tread design surface cause high undercut resistance during mold release, leading to defects such as permanent deformation and projection failure, especially in tires with complex tread patterns.
Innovation Solution
A mold design with segments that include a holder and plate spring members, allowing the design surface dividing mold parts to be elastically deformed and rotated away from the holder, reducing undercut resistance by using a plate spring member to facilitate mold release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If projections such as ribs or blades are provided on the tread design surface of each segment, then a tread pattern with recesses and protrusions can be formed on the tire tread, but high undercut resistance is caused during mold release, leading to permanent deformation and projection failure
Solution Approach 1:
The mold segments are designed to dynamically change their angular position during the release process. Each segment rotates around its own axis to change the orientation of projections relative to the tire tread, transitioning from a position that forms the tread pattern during vulcanization to a position that reduces undercut resistance during release. This dynamic adjustment allows the same mold structure to serve two opposing functions at different stages of the process.
Solution Approach 2:
The tread molding part is divided into multiple independent segments arranged in the circumferential direction, with each segment capable of independent rotation around its own axis. This segmentation allows each segment to be adjusted independently to optimize both tread pattern formation and reduce undercut resistance, rather than requiring the entire mold to be redesigned.
2Ease of operation
If the tread molding part is opened by moving segments toward the radially outer side, then the mold can be opened for tire release, but the projections cause excessively high undercut resistance that prevents clean release
Solution Approach 1:
Instead of simply moving segments radially outward, the invention incorporates rotational movement around each segment's axis. This dynamic motion changes the angular orientation of projections during release, allowing them to clear the tire tread more easily and reduce undercut resistance while maintaining the simplicity of radial opening motion.
Solution Approach 2:
The release mechanism adds a rotational dimension to the otherwise radial opening motion. By rotating segments around their own axes in addition to moving them radially outward, the invention creates a two-dimensional release path that effectively reduces undercut resistance without complicating the basic opening operation.
3Productivity
If segments are used to divide the tread molding part, then the mold can be opened and closed, but the projections on segment surfaces cause permanent deformation in the tire tread after mold releasing
Solution Approach 1:
The rotational adjustment of segments during release prevents permanent deformation by optimizing the separation path. By changing the angular position of projections relative to the tire tread during release, the mold minimizes stress and friction that would otherwise cause permanent deformation, while maintaining high productivity through efficient segment-based opening and closing.
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
Reduces undercut resistance, preventing defects and enabling easier release of tires from the mold, allowing for more complex tread patterns and reducing production costs by minimizing the required driving force.
Implementation Method 1
by elastic deformation of the plate spring member toward a radially inner side, the plurality of the design surface dividing mold parts are moved in a direction away from the holder
Data Source
AI summary
Provided are a mold for forming a tire including a tread molding part which is configured to be opened and closed by moving a plurality of segments in a radial direction, and a tire production method using the same. In the mold, each of the segments includes a holder; a plurality of design surface dividing mold parts disposed in a circumferentially arranged manner on a radially inner side of the holder; and a plate spring member to which the plurality of the design surface are fixed and in which both ends of the plate spring member in a circumferential direction are fixed to the holder, and when the tread molding part is opened, by elastic deformation of the plate spring member, the plurality of the design surface are moved in a direction away from the holder with the plurality of the design surface dividing mold parts being rotated.