Piston Seal Lip Geometry for Brake Fluid Compatibility
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Solution Overview
Problem
Existing piston-cylinder arrangements with moving seals face compatibility issues with various pressure media, leading to seal leakage and reduced product lifespan, especially when exposed to different brake fluids and their components.
Innovation Solution
A ring-shaped seal with a specific design featuring an inner and outer sealing lip, a circumferential recess, and a stop on the piston's outer surface, allowing for axial and rotational movement to create self-reinforcing sealing surfaces, enhancing compatibility and sealing efficiency under varying pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a moving seal made of silicone or EPDM material is used on the piston, then the seal can move along the housing wall to form a dynamic sealing surface, but the seal exhibits incompatibility with various pressure media leading to leakage and reduced lifespan
Solution Approach 1:
The patent changes the material parameter of the seal from conventional silicone or EPDM to fluoropolymer material, which has superior chemical resistance and compatibility with various pressure media including brake fluids, thereby resolving the incompatibility issue while maintaining dynamic sealing capability
Solution Approach 2:
The seal is designed as a composite structure combining fluoropolymer material with specific geometric features including a circumferential recess, inner and outer sealing lips, and an outwardly pointing second sealing lip, creating a multi-functional sealing element that addresses both material compatibility and sealing effectiveness
2Device complexity
If a conventional moving seal is used, then the seal structure is simple, but the seal fails to limit noise level and ensure sealing function during filling and operation
Solution Approach 1:
The seal is segmented into multiple functional zones: an inner sealing lip for primary sealing, an outwardly pointing second sealing lip for additional sealing and noise reduction, and a circumferential recess that provides structural support and defines the sealing geometry, with each segment contributing to overall performance
Solution Approach 2:
The seal design extends into the radial dimension with the outwardly pointing second sealing lip that contacts the housing wall, adding a secondary sealing dimension that enhances both sealing function and noise reduction without significantly increasing axial complexity
3Reliability
If the seal is designed with deformability to create rotational movement under vacuum, then sealing effectiveness improves during filling, but the seal geometry becomes more complex
Solution Approach 1:
The seal is designed with dynamic characteristics, allowing it to rotate transversely to the axial direction under vacuum conditions through its deformable geometry, enabling the outwardly pointing second sealing lip to contact the housing wall and form an additional sealing surface that prevents air ingress during filling operations
Solution Approach 2:
The seal utilizes a flexible fluoropolymer construction that can deform and rotate under pressure differential, with the circumferential recess and lip geometry designed to facilitate controlled deformation and rotational movement while maintaining structural integrity
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 design improves compatibility with diverse pressure media, reduces noise, and ensures effective sealing during both filling and operational phases, preventing air ingress and maintaining sealing integrity over time.
Implementation Method 1
in a first operating state when a vacuum is applied in the secondary pressure chamber relative to the environment, the outer first sealing lip is pulled in the axial direction towards the secondary pressure chamber
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a seal (1), wherein the seal is formed as a ring and can be arranged with an inner peripheral surface (2) on an outer peripheral surface (3) of a piston (4), wherein the seal (1) comprises an end face (6) facing in an axial direction (5) and an opposite second end face (8), the end faces being spaced by an extension E (7) of the seal, wherein an inner seal lip (10) facing inwards in a radial direction (9) and an outer first seal lip (11) facing outwards are arranged on the first end face (6). The seal (1) on the second end face (8) comprises a recess (13) running in a peripheral direction (12) and extending, in the region (14) of the inner peripheral surface, from the second end face (8) along the axial direction (5) over a length L (15), and also comprises a second seal lip (16) facing outwards on the second end face (8).