Switching Valve Spool Relief for Aircraft Pilot Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electro-hydrostatic circuits in aircraft face issues with overpressurization in pilot hydraulic lines due to thermal expansion, leading to overload on switching valves, which can cause weight increase when a separate relief valve is added to address this issue.
Innovation Solution
A switching valve configuration with a relief hole and valve body on the spool, energized by a second unit, which opens to discharge excess hydraulic pressure, integrated with a sealing material to prevent leakage, reducing weight and the need for additional relief valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate relief valve is added to the pilot hydraulic line to release overpressurization, then the pilot hydraulic pressure can be released, but the weight of the switching valve assembly increases
Solution Approach 1:
The relief valve function is merged with the switching valve by integrating the relief hole and valve body directly into the spool structure. The relief hole is formed in the spool, and the valve body is disposed on the spool, combining two previously separate functions (switching and pressure relief) into a single integrated component, thereby eliminating the need for a separate relief valve and reducing overall weight
2Stability of the object's composition
If the pilot hydraulic line is configured to suppress backflow and leakage, then stable switching is achieved, but overpressurization occurs due to thermal expansion
Solution Approach 1:
The relief valve mechanism provides feedback control for the pilot hydraulic pressure. When the pressure exceeds a predetermined value due to thermal expansion or other factors, the relief valve automatically opens to discharge excess pressure, and when pressure returns to normal levels, the valve closes again. This feedback mechanism maintains pressure within safe operating limits while preserving switching stability
Solution Approach 2:
The relief hole and valve body are pre-configured in the spool structure to provide pressure relief capability before overpressurization causes damage. The system is designed with this protective feature in advance, allowing it to handle thermal expansion and pressure buildup without compromising the sealed switching lines or causing failure
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 suppresses overpressurization, prevents hydraulic fluid leakage, and reduces the overall weight and power consumption of the electro-hydrostatic circuit by integrating relief functions directly on the spool, while maintaining stable operation.
Implementation Method 1
a spool that is disposed inside the sleeve to move in an axial direction by a pilot hydraulic pressure to switch between switching lines
Implementation Method 2
a first energizing unit that energizes the spool against the pilot hydraulic pressure
Implementation Method 3
a relief hole that is disposed on the spool to discharge the hydraulic fluid with the pilot hydraulic pressure
Implementation Method 4
a second energizing unit that energizes the valve body toward the relief hole of the spool against the pilot hydraulic pressure
Implementation Method 5
a valve body that closes the relief hole
Implementation Method 6
a sealing material that is disposed between the sleeve and the spool to seal the switching line against a pilot hydraulic line for supplying the hydraulic fluid with the pilot hydraulic pressure
Data Source
AI summary
A switching valve includes a sleeve on which a plurality of ports are disposed; a spool that is disposed inside the sleeve to move in an axial direction by a pilot hydraulic pressure to switch between switching lines each serving as a flow channel for hydraulic fluid that is formed by a combination of the ports; a first energizing unit that energizes the spool against the pilot hydraulic pressure; a relief hole that is disposed on the spool to discharge the hydraulic fluid with the pilot hydraulic pressure; a valve body that closes the relief hole; and a second energizing unit that energizes the valve body toward the relief hole of the spool against the pilot hydraulic pressure, and when the pilot hydraulic pressure exceeds a predetermined value, opens the relief hole.