Brake Cylinder Dust Boot Venting for Pressure-Induced Flipping
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Solution Overview
Problem
Conventional wheel brake cylinder sealing systems face challenges in durability and resistance to corrosion, particularly under high temperature and extreme environmental conditions, which can lead to boot deformation, flipping, and rupture, compromising sealing functions.
Innovation Solution
A resilient boot sealing system incorporating a normally closed pressure relief valve that automatically and temporarily opens to relieve pressure imbalances between the interior and exterior of the sealed chamber, preventing boot deformation and flipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetically closed boot is used to prevent foreign substance ingress, then sealing protection is improved, but internal pressure increases under high temperature conditions leading to boot deformation and rupture
Solution Approach 1:
The boot incorporates a microporous membrane structure that allows controlled pressure equalization between the interior chamber and exterior environment. The microporous material permits gas permeation to relieve internal pressure buildup under high temperature conditions while maintaining barrier properties against liquid contaminants and foreign substances, thus resolving the contradiction between hermetic sealing and pressure management.
2Object-affected harmful factors
If the boot is sealed hermetically to prevent contamination, then protection against foreign substance is improved, but pressure imbalance causes boot flipping and interface detachment
Solution Approach 1:
The microporous membrane enables selective permeability that allows gas molecules to pass through for pressure equalization while blocking larger liquid contaminant particles. This maintains the boot's hermetic sealing function against contamination while preventing pressure-induced flipping and interface detachment by allowing controlled pressure relief.
3Duration of action of stationary object
If the boot material is made robust to resist deformation, then durability is improved, but flexibility for relative displacement between piston and housing is reduced
Solution Approach 1:
The boot utilizes a flexible bellows structure with accordion-like folds that provide significant axial displacement capability while maintaining structural integrity. The thin-walled flexible material allows the boot to expand and contract axially to accommodate piston movement relative to the housing, yet remains durable enough to resist degradation from temperature extremes and mechanical stress over extended service life.
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 pressure relief valve maintains pressure balance, reduces boot deformation, and prevents flipping, thereby enhancing the durability and corrosion resistance of the sealing system, ensuring effective sealing and protection against contamination.
Implementation Method 1
when pressure is not equal between the interior, i.e. the sealed chamber, and exterior
Implementation Method 2
The flexible boot has bellows between the interface sections and allows relative displacement between actuation member and housing
Implementation Method 3
With increasing of the temperature (pressure) in the interior of the chamber, conventional boot expands in balloon-like manner due to the thermal expansion
Data Source
AI summary
A dust boot sealing system for automotive brake cylinders, is arranged for dust protection between a linear actuation member and a housing of the brake cylinder. The boot comprises flexible bellows between two concentrical interface portions, and the both interface portions rest radially outwards from their respective counterpart seats in circumferential grooves on housing and actuation member. The boot is provided with pressure relief valve and with integrated pressure relief valve function which automatically and temporarily changes into open status under a pressure gradient decline in direction from interior to exterior, with respect to the boot.