Electrohydraulic Poppet Valve with Variable Flow Restriction
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Solution Overview
Problem
Existing electrohydraulic poppet valves face limitations in controlling high flow rates with large hydraulic actuators, as they require additional pressure compensators and exhibit non-linear relationships between fluid pressure and electric current, constraining scalability and accuracy.
Innovation Solution
The design incorporates a control valve with a main poppet and an electrohydraulic pilot valve featuring a variable flow restriction passageway and a pressure compensator, allowing for proportional control of fluid flow through a solenoid-actuated pilot passage, which adjusts pressure differentials to maintain efficient operation across varying pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large variable orifice is placed in the control passage to achieve high flow rates, then the valve can control high flow rates rapidly, but additional pressure compensators are required and the relationship between fluid pressure and electric current becomes non-linear
Solution Approach 1:
The patent applies a variable orifice in the control passage that dynamically changes its opening area in response to poppet displacement. As the main poppet moves from the closed position, the variable orifice gradually opens, allowing the control passage flow area to increase dynamically. This dynamic adjustment enables the valve to maintain stable pressure control throughout the poppet stroke without requiring additional pressure compensators, while avoiding the non-linear relationships associated with large fixed orifices.
2Quantity of substance
If the control passage orifice is enlarged to increase flow capacity, then high flow rates can be controlled, but the relationship between fluid pressure and electric current becomes non-linear affecting accurate control
Solution Approach 1:
The variable orifice in the control passage dynamically adjusts its flow area based on the main poppet position. When the poppet is near the closed position, the orifice remains relatively closed, maintaining a linear relationship between solenoid current and control chamber pressure for accurate proportional control. As the poppet opens, the variable orifice gradually increases its opening, allowing sufficient flow capacity to be achieved without creating the non-linear pressure-current relationships that would occur with a large fixed orifice.
3Length of moving object
If a solenoid is designed to provide both high force and large stroke, then it can achieve large poppet strokes, but the solenoid mechanism greatly constrains the scalability of the valve
Solution Approach 1:
The patent introduces a pilot valve as an intermediary mechanism between the solenoid and the main poppet. The solenoid controls a small pilot poppet that regulates pressure in a pilot control chamber. This pilot pressure then acts on the main poppet to produce the desired large stroke. By using the pilot valve as an intermediary, the system achieves large poppet strokes without requiring a large-stroke solenoid, thereby maintaining scalability and allowing the same solenoid design to be used across different valve sizes.
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 solution enables rapid and proportional control of high flow rates, maintaining accurate control and scalability by compensating for pressure fluctuations, thus overcoming the limitations of existing valve designs.
Implementation Method 1
an electrically operated sub-pilot valve selectively opens to produce a decrease in the pilot control chamber pressure
Implementation Method 2
A passageway extends between the second port and the primary control chamber and includes a variable flow restriction that decreases in magnitude as the main poppet moves away from the valve seat
Implementation Method 3
A main poppet is moveably received within the primary bore to selectively engage and disengage the valve seat
Data Source
AI summary
A control valve includes a main poppet that moves in response to pressure in a primary control chamber and thereby controls the flow of fluid through a valve seat between first and second ports. A passageway extends between the second port and the primary control chamber and includes a variable flow restriction that decreases as the main poppet moves away from the valve seat. An electrohydraulic pilot valve has a pilot poppet which controls fluid flow from the primary control chamber to the first port in response to pressure in a pilot control chamber. A sub-pilot valve selectively releases pressure in the pilot control chamber to operate the pilot poppet to open and close a path between the inlet and the outlet. Using an electrohydraulic pilot valve enables the main poppet to operate quickly in controlling large fluid flow rates. Unidirectional and bidirectional versions of the control valve are described.