Nested Multi-Element Seal Assembly for Uneven Shaft Surfaces
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Solution Overview
Problem
Conventional seal assemblies fail to maintain a fluid-tight seal when the movable shaft or rod ages, as the radially outer face becomes uneven, leading to inconsistencies that the sealing surface cannot conform to.
Innovation Solution
A multiple sealing element assembly with an intermediate sealing element and two end sealing elements, each with complementary surface features and varying hardness values, designed to nest together within a gland groove, ensuring a secure and fluid-tight seal despite surface irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single sealing element is used, then the structure is simple, but the seal cannot maintain fluid-tightness when the shaft surface becomes uneven due to aging
Solution Approach 1:
The sealing element is divided into multiple segments (first sealing element, second sealing element, third sealing element) arranged in series along the shaft. Each segment can independently deform to accommodate surface irregularities, with the segmented structure allowing better adaptation to uneven shaft surfaces while maintaining overall sealing effectiveness
Solution Approach 2:
Different portions of the sealing assembly have different hardness values - the first sealing element has a first hardness value, the second sealing element has a second hardness value, and the third sealing element has a third hardness value. This local variation in material properties allows each segment to optimally conform to different regions of the shaft surface, improving sealing reliability
2Strength
If the sealing element is made harder to resist deformation under pressure, then structural strength improves, but the ability to conform to uneven shaft surfaces decreases
Solution Approach 1:
The patent applies different hardness values to different sealing elements (first hardness value for first sealing element, second hardness value for second sealing element, third hardness value for third sealing element). This creates a gradient structure where softer segments can deform to accommodate surface irregularities while harder segments provide structural support and resistance to pressure, resolving the contradiction between strength and adaptability
Solution Approach 2:
The sealing assembly uses composite construction with multiple materials of different hardness properties arranged in sequence. This composite approach allows the assembly to exhibit both the conformability of softer materials and the pressure resistance of harder materials, achieving both goals simultaneously
Data Source
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AI summary
A sealing assembly (30) that includes first, second and third sealing elements, where the first sealing element (40) is disposed between the second and third sealing elements (60, 80). The sealing elements are shaped in a complementary manner so that the sealing elements when assembled nest together. The sealing elements also have different hardness values associated therewith.