Three-Position Slide Valve Switching to Limit Hydraulic Pressure Peaks
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Solution Overview
Problem
High-pressure peaks occur when changing direction in the movement of aircraft actuators controlled by hydraulically controlled slide valves due to sudden depressurization from feed pressure to return pressure, leading to oscillations and potential damage.
Innovation Solution
Implementing an intermediate step where both control chambers are simultaneously pressurized to cancel hydraulic forces, allowing the slide to return to the central position under centering springs, thereby reducing pressure peaks and oscillations, and enabling progressive depressurization of pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the slide valve switches directly from one end position to the other by changing pressure from feed to return, then the switching speed is fast, but pressure peaks occur causing oscillations and potential damage
Solution Approach 1:
The method applies preliminary action by first pressurizing both control chambers simultaneously before switching to the final position. This intermediate step prepares the system by canceling hydraulic forces on the slide and progressively depressurizing pipes, preventing sudden pressure peaks when the slide reaches its end position
Solution Approach 2:
The patent introduces an intermediary state where both control chambers are pressurized simultaneously. This intermediate position acts as a mediator between the two end positions, allowing progressive depressurization of pipes and eliminating the direct pressure transition that causes harmful pressure peaks
2Object-affected harmful factors
If both control chambers are pressurized simultaneously for a determined length of time, then pressure peaks are reduced and movement is more progressive, but the switching time between end positions increases
Solution Approach 1:
The method applies partial action by pressurizing both chambers only for a determined length of time sufficient to cancel hydraulic forces and allow progressive depressurization, but not indefinitely. This optimized duration achieves the benefit of reducing pressure peaks while minimizing the time penalty
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 method reduces pressure peaks and oscillations, ensuring a more progressive movement and faster switching between end positions, minimizing the risk of pipe depressurization-related issues.
Implementation Method 1
the slide is urged towards a stable central position by centering springs
Implementation Method 2
The slide can be moved into end positions on either side of the central position by delivering a fluid under pressure into respective control chambers
Data Source
AI summary
A method of controlling a hydraulic valve includes putting a first control chamber under pressure and putting a second control chamber to return so as to cause a slide to move into one of two end positions, putting a second control chamber under pressure and putting the first control chamber to return, thereby causing the slide to move into the other one of the two end positions. An intermediate step of applying pressure to the one of the first or second control chamber that was connected to return can be provided so that both control chambers are maintained simultaneously under pressure for a determined length of time.