Relay Valve Piston Movement Limiting Mechanism
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Solution Overview
Problem
Conventional relay valves in compressed-air brake systems lack the ability to effectively modulate output pressure beyond control pressure modulation, limiting their dynamic range and control precision.
Innovation Solution
Incorporating a movement limiting mechanism that adjusts and locks the axial movement range of the control piston, allowing for independent control of outlet pressure from both high and low sides, using a self-locking or electromagnetically controlled mechanism to restrict piston movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If control pressure modulation is used to modulate output pressure, then the relay valve can provide proportional control, but the dynamic range and control precision are limited
Solution Approach 1:
The patent introduces a movable limiting element that can dynamically adjust the axial movement range of the control piston. This dynamic adjustment capability allows the system to adapt to different control requirements, expanding the dynamic range beyond what fixed control pressure modulation can achieve. The limiting element can be repositioned to provide different movement constraints, enabling versatile control across various operating conditions.
Solution Approach 2:
The patent changes the physical parameter of piston movement range by introducing an adjustable limiting mechanism. By modifying the axial movement range of the control piston through the limiting element, the system achieves enhanced control precision and expanded dynamic range. This parameter change approach allows independent control of outlet pressure from both high and low sides, overcoming the limitations of control pressure modulation alone.
2Adaptability or versatility
If the axial movement range of the control piston is increased to expand dynamic range, then more pressure modulation is possible, but control precision deteriorates
Solution Approach 1:
The movable limiting element provides dynamic adjustment of the piston movement range, allowing the system to optimize between dynamic range and control precision based on specific operational requirements. The limiting element can be repositioned to create appropriate movement constraints that maintain precision while enabling sufficient dynamic range for the given application.
Solution Approach 2:
The patent introduces a adjustable parameter (the axial movement range limited by the limiting element) that can be optimized for different operating conditions. By carefully controlling the movement range through the limiting mechanism, the system achieves both adequate dynamic range and maintained control precision, resolving the trade-off between these two parameters.
3Adaptability or versatility
If a movement limiting mechanism is added to control piston movement, then outlet pressure can be limited from both high and low sides, but device complexity increases
Solution Approach 1:
The limiting element serves multiple functions: it limits the axial movement of the control piston, enables pressure limitation from both high and low sides, and can be adjusted to provide different movement ranges. This multi-functionality justifies the added complexity by providing comprehensive pressure control capability in a single integrated component.
Solution Approach 2:
The movable limiting element acts as an intermediary between the control piston and the pressure control system. It mediates the relationship between piston movement and pressure output, providing a controlled interface that enables precise pressure limitation while maintaining system integrity. This intermediary approach allows for controlled complexity that delivers significant functional benefits.
4Measurement precision
If the control piston movement is restricted to improve control precision, then pressure modulation accuracy increases, but the ability to respond to control pressure changes is reduced
Solution Approach 1:
The movable limiting element provides dynamic control of piston movement constraints, allowing the system to optimize between precision and response speed based on operational needs. The limiting mechanism can be adjusted to provide appropriate movement freedom while maintaining precision, enabling the system to respond effectively to control pressure changes without sacrificing modulation accuracy.
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
Enables precise modulation of output pressure by limiting the axial movement range of the control piston, enhancing control precision and dynamic range, and allowing for stable pressure settings regardless of control pressure changes.
Implementation Method 1
a control piston (14) arranged in a housing (12) and being axially movable by means of a control pressure supplied from a control port (20)
Implementation Method 2
EP 2 407 355 B1 discloses a relay valve comprising an additional elastic element for causing offset and increased factor of the outlet pressure
Data Source
Figure 1
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Figure 4~5
AI summary
A relay valve (10) for a compressed-air brake system of a commercial vehicle comprises a control piston (14) arranged in a housing (12) and being axially movable by means of a control pressure supplied from a control port (20); a valve means (24) comprising a valve body (28) being axially movable by means of an axial movement of said control piston (14), wherein said valve body (28) controls fluid connection between a supply port (26) and an outlet port (22); and a movement limiting mechanism (38) configured to limit an axial movement range of said control piston (14) if required.