Annular Seal Outer-Layer Thickness Control to Prevent Cracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing annular seal materials often result in cracking of the outer layer and protrusion of the core from the outer layer, and are complex and costly.
Innovation Solution
An annular seal material comprising a core and an outer layer with a thick film portion and a non-thick film portion in the cross section, where the average thickness ratio of the thick film portion to the non-thick film portion is between 1.05 and 1.20, and a cross-sectional diameter difference of 0.01 mm or less, manufactured through a preforming and hot pressing process using crosslinkable rubber compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the outer layer portion is inflated during manufacturing, then the seal material can be formed into shape, but the outer layer portion material may break causing cracks
Solution Approach 1:
The patent applies local quality by creating a two-layer structure where the outer layer has different thickness at different locations: a thicker portion at the inflation side and a thinner portion at the opposite side. This localized thickness variation allows the thicker region to withstand inflation pressure without cracking while maintaining the overall seal shape.
Solution Approach 2:
The patent changes the physical parameter of outer layer thickness to resolve the contradiction. By making the outer layer thickness non-uniform (thicker at inflation side, thinner at opposite side), the structure can accommodate inflation forces without breaking while still forming the required seal shape.
2Stability of the object's composition
If a connecting member is disposed at the seam to join layers, then the layers can be connected, but the two-layer structure is lost at the seam location
Solution Approach 1:
The patent removes the connecting member from the seam location and instead allows the inner layer to naturally extend across the seam. This extraction of the connecting member eliminates the disruption to the two-layer structure while still achieving layer connection through the continuous inner layer.
3Shape
If the core material is inserted into the mold cavity during molding, then the core can be positioned, but the core may protrude from the gap between outer layers
Solution Approach 1:
The patent performs preliminary action by pre-forming the outer layer with a thicker portion at the inflation side before core insertion. This pre-formed thick portion creates a natural barrier that prevents core protrusion during molding, while still allowing proper core positioning in the cavity.
4Manufacturing precision
If the manufacturing process uses multiple steps and components, then the seal material can be properly formed, but the process becomes complicated and costly
Solution Approach 1:
The patent merges the outer layer formation and core positioning into a single integrated molding process. The two-layer outer structure with varying thickness is formed in one step, and the core is positioned simultaneously, eliminating the need for separate connecting members and multiple assembly steps, thus simplifying the overall manufacturing process.
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 solution effectively prevents cracking of the outer layer and protrusion of the core, simplifying the manufacturing process and reducing costs.
Implementation Method 1
a preforming step of providing one or two or more rope-like preforms comprising an uncrosslinked core made of a crosslinkable rubber composition for a core, and an uncrosslinked outer layer, made of a crosslinkable rubber composition for an outer layer, covering a periphery of the uncrosslinked core; and a hot pressing step of contacting two end portions of the rope-like preform with each other and placing the same in a mold to carry out hot press molding
Data Source
AI summary
The present invention relates to an annular seal material comprising a core and an outer layer covering a periphery of the core, wherein the outer layer has a thick film portion and a non-thick film portion in a cross section in a circumferential direction. According to the present invention, provided are an annular seal material that is constituted of a core and an outer layer and that suppresses cracking in the outer layer and protrusion of the core from the outer layer, and a method for manufacturing the same.