Piston Seal Grooves Stabilize Master Cylinder Orientation
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Solution Overview
Problem
In master cylinders, the piston seal's orientation becomes unstable when pressure is high, causing the intermediate protrusion section to have lower pressure between itself and the inner circumferential lip section, making it difficult to separate and maintain proper alignment.
Innovation Solution
The piston seal features an annular base section with an inner circumferential lip, an outer circumferential lip, and an intermediate protrusion section, where inner and outer circumferential side grooves are formed to enhance stability, ensuring proper alignment and separation by matching the pressure within the seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intermediate protrusion section is made to contact the inner circumferential lip section under high pressure, then sealing performance is improved, but the pressure difference causes the intermediate protrusion section to stick and orientation becomes unstable
Solution Approach 1:
The intermediate protrusion section is divided into multiple segments by forming grooves (first grooves and second grooves) that extend in the axial direction. This segmentation allows pressure to be equalized across different sections, preventing the pressure difference that causes sticking while maintaining sealing contact between the inner circumferential lip section and the intermediate protrusion section.
Solution Approach 2:
The grooves act as intermediary channels that allow pressure equalization between the high-pressure region (between the inner circumferential lip section and intermediate protrusion section) and the lower-pressure peripheral region. This mediates the pressure difference that would otherwise cause the intermediate protrusion section to stick, enabling stable orientation while maintaining sealing performance.
2Strength
If pressure in the space between the intermediate protrusion section and inner circumferential lip section is lower than peripheral pressure, then sealing force is increased, but separation becomes difficult and orientation stability is reduced
Solution Approach 1:
By segmenting the intermediate protrusion section with axial grooves, the pressure distribution is equalized across all segments. This prevents the formation of a low-pressure zone that would create excessive sealing force and make separation difficult, while still maintaining adequate sealing contact through the segmented structure.
Solution Approach 2:
The grooves change the pressure parameter distribution within the seal structure by providing communication paths between high and low pressure regions. This parameter change (pressure equalization) reduces the pressure differential that causes sticking, making separation easier while maintaining sealing effectiveness through the segmented contact surfaces.
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
This configuration stabilizes the piston seal's orientation, preventing separation issues and ensuring smooth operation by maintaining consistent pressure across the seal components.
Implementation Method 1
at least one inner circumferential side groove extending in an axial direction and opened at a front end side of the intermediate protrusion section is formed in a surface of the inner circumferential lip section side of the intermediate protrusion section
Data Source
AI summary
In a master cylinder, a piston seal provided in a circumferential groove includes an annular base section, an inner circumferential lip section protruding from an inner circumferential side of the base section to come into sliding contact with an outer circumferential surfaced of a piston, an outer circumferential lip section protruding from an outer circumferential side of the base section to abut the circumferential groove, and an intermediate protrusion section protruding from a portion between the inner circumferential lip section and the outer circumferential lip section of the base section to a position further forward than the outer circumferential lip section. At least one inner circumferential side groove extending in an axial direction and opened at a front end side of the intermediate protrusion section is formed in a surface of the inner circumferential lip section side of the intermediate protrusion section.