Holding Seal Material With Varying Skin Layer Thickness
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Solution Overview
Problem
Existing exhaust gas purifying apparatuses face challenges in maintaining a consistent holding force due to thermal expansion differences between ceramic exhaust gas treatment bodies and metal casings, leading to potential leakage and damage from vibrations, especially when exposed to high-temperature and high-pressure exhaust gases.
Innovation Solution
A holding seal material with inorganic fibers coated with skin layers containing inorganic particles, where the thickness of these skin layers varies across the material's surface, providing increased friction and contact pressure at one surface while allowing flexibility and reduced contact points at others, ensuring a stable holding force despite thermal expansion variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the holding seal material uses uniform skin layer thickness, then the structure is simple, but the holding force becomes unstable due to thermal expansion differences
Solution Approach 1:
The patent applies local quality by varying the skin layer thickness across different regions of the holding seal material. The first skin layer has a greater thickness than the second skin layer, creating localized differences in mechanical properties. This allows the material to have enhanced friction and contact pressure at the first surface for improved holding force, while maintaining flexibility and adaptability at the second surface to accommodate thermal expansion variations between the exhaust gas treatment body and casing.
2Force
If the holding seal material increases friction at one surface, then the holding force improves, but the flexibility and adaptability to thermal expansion decreases
Solution Approach 1:
The patent resolves this contradiction by assigning different skin layer thicknesses to different surfaces. The first surface with the thicker skin layer provides high friction and contact pressure for strong holding force, while the second surface with the thinner skin layer maintains flexibility and adaptability to accommodate thermal expansion differences between components.
Solution Approach 2:
The holding seal material is constructed as a composite structure combining inorganic fibers with skin layers of varying thickness. This composite design allows different regions to serve different functions: the thicker skin layer region provides mechanical strength and friction for holding, while the thinner skin layer region provides flexibility for thermal accommodation, achieving both high holding force and thermal adaptability simultaneously.
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 holding seal material effectively maintains a high holding force on the exhaust gas treatment body, is heat-resistant, and easily bendable, preventing leakage and damage while accommodating thermal expansion, thus enhancing the performance and durability of exhaust gas purifying apparatuses.
Implementation Method 1
the thicknesses of the skin layers satisfy a following relational expression (1)... providing increased friction and contact pressure at one surface
Implementation Method 2
there are cases in which the gap between the exhaust gas treatment body and the casing varies due to the difference in thermal expansion coefficient between the exhaust gas treatment body and the casing
Data Source
AI summary
A holding seal material includes inorganic fibers, skin layers provided around the inorganic fibers, inorganic particles included in the skin layers, a first main surface, and a second main surface. Thicknesses of the skin layers satisfy X>Y≧Z. X is a thickness of the skin layer of the inorganic fibers in a vicinity of the first main surface. Y is a thickness of the skin layer of the inorganic fibers in a vicinity of a center of the holding seal material in a thickness direction. Z is a thickness of the skin layer of the inorganic fibers in a vicinity of the second main surface.