Master Cylinder Piston Seal Stability Design
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Solution Overview
Problem
In a master cylinder, an unstable posture of the piston seal can inhibit smooth brake fluid supply due to the piston seal's position and interaction with the reservoir, leading to inefficiencies in fluid pressure distribution.
Innovation Solution
A master cylinder design featuring a piston seal with an annular base section, inner and outer circumferential lip sections, and an intermediate protrusion section, where the inner circumferential lip section is bent to align with the pressure state, and a step difference section at the outer circumference of the base section to maintain stability and facilitate communication between the supply path and pressure chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the piston seal is installed in the circumferential groove without additional stabilizing structures, then the device complexity is reduced, but the posture stability of the piston seal deteriorates
Solution Approach 1:
The piston seal employs an asymmetric step difference section where the inner circumferential side is longer than the outer circumferential side. This asymmetric design creates a stable posture by forming a stepped structure that prevents rotation and ensures proper positioning within the circumferential groove, resolving the contradiction between stability and complexity.
2Adaptability or versatility
If the inner circumferential lip section is made rigid to maintain sealing position, then the manufacturing precision is improved, but the ability to adapt to pressure state changes deteriorates
Solution Approach 1:
The inner circumferential lip section is designed as a flexible, bendable component rather than a rigid structure. It can dynamically adjust its position and orientation in response to pressure differential forces between the pressure chamber and supply path, while maintaining manufacturing precision through controlled flexibility that allows adaptive sealing.
Solution Approach 2:
The lip section's physical state changes in response to pressure parameters. When pressure differential exceeds a threshold, the lip bends to open the communication path; when pressure equalizes, the lip returns to its original position. This parameter-driven behavior enables adaptability without sacrificing manufacturing precision.
3Stability of the object's composition
If the step difference section is made longer in the axial direction to improve stability, then the posture stability is improved, but the device complexity increases
Solution Approach 1:
The step difference section serves multiple functions simultaneously: it provides axial positioning, prevents radial displacement, ensures proper orientation, and creates the necessary clearance for brake fluid flow. By consolidating these functions into a single structural feature, the design achieves enhanced stability without proportionally increasing complexity.
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 design stabilizes the piston seal's posture, ensuring consistent brake fluid supply and pressure distribution, enhancing the efficiency of brake fluid flow and reducing the risk of fluid flow obstruction.
Implementation Method 1
the inner circumferential lip section is bent in a direction approaching the intermediate protrusion section in response to the pressure state between the pressure chamber and the supply path
Implementation Method 2
The circumferential groove has a step section at a circumferential wall of an opening section side of the cylinder main body, the step section always abuts an outer circumferential surface of the step difference section
Implementation Method 3
an inner circumference thereof comes in sliding contact with the piston to seal between the supply path and the pressure chamber
Data Source
AI summary
A master cylinder includes a piston seal installed in a circumferential groove. The piston seal includes an annular base section, an inner circumferential lip section protruding from an inner circumferential side of the base section to come in sliding contact with an outer circumferential surface 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 between the inner circumferential lip section and the outer circumferential lip section of the base section to a forward side of the outer circumferential lip section. A step difference section is formed at the outer circumferential side. The circumferential groove has a step section that always abuts an outer circumferential surface of the step difference section. A communication path configured to bring a supply path that is in communication with a reservoir and the bottom section side of the circumferential groove in communication with each other is formed between the step difference section and the step section.