Spherical Annular Seal with Solid Lubricant Layer
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Solution Overview
Problem
Existing spherical annular seal members for exhaust pipe joints suffer from abnormal frictional noise and leakage due to the presence of heat-resistant materials at the surface, which can lead to oxidative wear and stick-slip phenomena, especially at high temperatures.
Innovation Solution
A spherical annular seal member with a reinforcing member made from a metal wire net and a heat-resistant material containing expanded graphite, integrated with a sintered solid lubricant composed of hexagonal boron nitride and a molten fluorocarbon resin, forming a smooth surface to prevent damage to the mating member and reduce frictional noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat-resistant material (expanded graphite) is used at the sliding surface, then sealing performance is improved, but abnormal frictional noise and oxidative wear occur
Solution Approach 1:
The seal member is divided into two distinct layers: a base layer with heat-resistant material and reinforcing member for sealing, and a separate sliding layer with solid lubricant for friction reduction. This segmentation allows each layer to perform its specialized function without the conflicts present in the integrated structure.
Solution Approach 2:
The heat-resistant material is extracted from the sliding surface and confined to the base layer, while the sliding surface is dedicated solely to solid lubricant material. This extraction removes the source of oxidative wear and abnormal noise from the friction interface.
2Strength
If reinforcing member proportion is increased, then structural strength is improved, but leakage occurs through gaps around the reinforcing member
Solution Approach 1:
The seal member employs different material compositions in different regions: the base layer contains high比例的 reinforcing member for strength, while the sliding layer contains solid lubricant for sealing. This local differentiation allows both strength and sealing performance to be optimized in their respective zones.
3Temperature
If heat-resistant material exposure at sliding surface is large, then heat resistance is improved, but stick-slip phenomenon causes abnormal frictional noise
Solution Approach 1:
The solid lubricant acts as an intermediary material between the heat-resistant base layer and the mating member. It mediates the interaction at the sliding interface, providing low-friction contact while allowing the heat-resistant material to remain in the base layer where it can fulfill its thermal function without causing stick-slip noise.
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 seal member effectively eliminates abnormal frictional noise and ensures stable sealing characteristics over extended periods, even at high temperatures, by integrating a sintered solid lubricant with the reinforcing member and heat-resistant material, preventing oxidative wear and leakage.
Implementation Method 1
a sliding layer formed by a sintered solid lubricant of a lubricating composition containing hexagonal boron nitride and a molten fluorocarbon resin
Implementation Method 2
a heat-resistant material containing expanded graphite
Implementation Method 3
a reinforcing member made from a metal wire net
Data Source
AI summary
In a spherical annular seal member 38, a spherical annular base member 36 is constructed so as to be provided with structural integrity as a heat-resistant material 6 and a reinforcing member 5 are compressed to each other and intertwined with each other. In an outer layer 37, the heat-resistant material 6, a sintered solid lubricant constituted by a lubricating composition, and the reinforcing member 5 made from a metal wire net are compressed such that the sintered solid lubricant and the heat-resistant material 6 are filled in meshes of the metal wire net of the reinforcing member 5, and the solid lubricant, the heat-resistant material 6, and the reinforcing member 5 are integrated in mixed form, an outer surface 39 of that outer layer 37 being thus formed into a smooth surface 42 in which a surface 40 constituted by the reinforcing member 5 and a surface 41 constituted by the sintered solid lubricant are present in mixed form.