Three-Position Spool Valve Control for Pressure Spike Reduction
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Solution Overview
Problem
High-pressure aircraft systems experience pressure peaks during directional changes in hydraulic cylinder movements due to sudden depressurization of pipes, leading to instability and potential damage.
Innovation Solution
A method for controlling hydraulic distributors involves simultaneously pressurizing both control chambers for a defined time to maintain stable pressure, allowing the spool to return to the central position smoothly and preventing oscillation, thereby reducing pressure spikes by gradual depressurization and enabling fast switching between extreme positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the spool valve switches directly from one extreme position to the other, then the switching speed is fast, but pressure peaks occur due to sudden depressurization
Solution Approach 1:
The patent applies preliminary action by first pressurizing the second control chamber before the spool reaches the central position. This anticipatory pressurization ensures that when the spool passes through the central position and the first chamber is depressurized, the second chamber is already pressurized, preventing sudden pressure drops and associated harmful effects while maintaining fast switching.
Solution Approach 2:
The patent implements beforehand cushioning by maintaining pressure in the second control chamber during the transition phase. This pressure cushioning prevents the sudden depressurization that would otherwise occur when the spool passes through the central position, thereby eliminating pressure peaks while preserving rapid switching capability.
2Object-affected harmful factors
If the spool moves gradually through the central position, then pressure peaks are reduced, but the switching time increases
Solution Approach 1:
The patent uses preliminary action by pre-pressurizing the second control chamber before the spool reaches the central position. This allows the spool to maintain a relatively fast switching speed while the pre-prepared pressure in the second chamber prevents harmful pressure peaks during the transition.
Solution Approach 2:
The patent applies dynamics by controlling the pressurization timing of the second control chamber based on the spool's position. The pressurization is activated at the optimal moment during the transition, allowing the system to dynamically balance between switching speed and pressure peak reduction rather than forcing a gradual movement.
3Reliability
If the spool oscillates during position changes, then the system responds to pressure changes, but stability is reduced and pressure peaks increase
Solution Approach 1:
The patent implements feedback by using the spool's position and pressure chamber states to control the timing of pressurization in the second chamber. This feedback mechanism ensures that pressurization occurs at the precise moment needed to counteract potential oscillations and pressure peaks, thereby improving stability while eliminating harmful pressure variations.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the pressure in the control chambers based on the spool's position and movement state. By changing the pressure parameters at critical moments during the transition, the system prevents oscillations and pressure peaks while maintaining stability and fast switching.
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 approach reduces pressure peaks and oscillations, ensuring a more gradual and stable movement of the spool, minimizing the risk of damage and maintaining system integrity during directional changes.
Implementation Method 1
Hydraulic spool valves mounted movably in a body and returned to a stable central position by centering springs
Implementation Method 2
The drawer is movable in extreme positions on either side of the central position by the supply of a pressurized fluid into respective control chambers
Implementation Method 3
In the extreme positions, the distributor connects the supply port to one of the chambers, and the return port to the other chamber. In the central position, the distributor connects the two chambers to the return port.
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling a hydraulic distributor comprising a supply port (11), a return port (12) and two service ports (13,14), and a spool (16) movably mounted in a body between two extreme positions (18,19) in one of which the spool connects the supply port with one of the service ports and the return port with the other of the service ports, and in the other of which at least the one of the service ports that was connected with the return port is connected with the supply port, passing through a stable central position (17) in which the distributor connects the return port with both service ports, the body delimiting the first and second control chambers (20,21) of the spool,The method comprises pressurizing the first control chamber (20) and returning the second control chamber (21) to its return position, causing the spool to move to one of the extreme positions; pressurizing the second control chamber (21) and returning the first control chamber (20) to its return position, causing the spool to move to the other extreme position; and the intermediate step between the aforementioned steps of pressurizing the control chamber (21) which is in its return position so that both chambers are simultaneously maintained under pressure for a determined time (ΔT).