Relay Piston Guide Ribs for Foot Brake Module Leak Control
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Solution Overview
Problem
Existing foot brake modules face issues with tilting of the secondary piston in the guide sleeve, leading to audible leakage and potential wear, which can violate regulatory standards and cause delays in brake application and release.
Innovation Solution
Incorporating a set of guiding features, such as raised portions or ribs, around the circumference of the secondary piston to reduce tilting and maintain stability within the guide sleeve, while allowing for smooth movement and minimizing gaps to prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the secondary piston is allowed to move freely in the guide sleeve, then the brake response time is reduced, but the piston tilts causing audible leakage and potential wear
Solution Approach 1:
The patent applies local quality by adding guiding features (such as ribs or raised portions) at specific locations on the secondary piston shaft. These features are not distributed uniformly but are strategically positioned to provide guidance where needed while maintaining freedom of movement in other areas. The guiding features create localized contact points with the guide sleeve that prevent tilting without restricting the piston's longitudinal movement, thus resolving the contradiction between fast response and stability.
Solution Approach 2:
The guiding features on the piston shaft act as an intermediary element between the piston and the guide sleeve. Instead of the entire piston surface contacting the sleeve (which would restrict movement) or no contact at all (which would allow tilting), the guiding features serve as intermediate contact points. These features transmit guidance forces to prevent tilting while minimizing interference with the piston's primary movement function, thereby maintaining both speed and reliability.
2Reliability
If guiding features are added to the secondary piston to reduce tilting, then piston stability is improved, but the complexity of the piston structure increases
Solution Approach 1:
The patent applies segmentation by dividing the piston shaft into functional zones: the main shaft body that moves freely, and the guiding features (ribs or raised portions) that provide stability. This segmentation allows the piston to have different properties in different regions - the majority of the shaft maintains smooth movement while specific segmented portions provide guidance. This resolves the contradiction by adding minimal structural complexity only where needed rather than complicating the entire piston structure.
Solution Approach 2:
Instead of making the guide sleeve complex with multiple guiding surfaces, the patent inverts the approach by adding simple guiding features to the piston shaft itself. This reversal of where the guiding mechanism is located simplifies the overall system - the piston becomes the active element providing its own guidance rather than relying on a complex passive guide structure. This reduces overall device complexity while achieving the stability goal.
Data Source
AI summary
A valve assembly is provided comprising: an air supply port; an air delivery port; a guide sleeve; and a piston positioned in the guide sleeve and movable between first and second positions to allow air to flow from the air supply port to the air delivery port, wherein a gap is defined between a minor outer diameter of a shaft of the piston and the guide sleeve; wherein the shaft defines an inner bore for passage of air and comprises a plurality of raised surfaces around a circumference of the shaft that narrows the gap and thereby reduces tilting of the piston as it moves in the guide sleeve between the first and second positions. Other embodiments are provided.