Shuttle Valve Pressure Segmentation for Redundant Cylinder Control
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Solution Overview
Problem
Existing hydraulic assemblies with redundant directional control valve modules fail to maintain full functionality of actuators, particularly double-acting cylinders, when one directional valve fails, leading to functional restrictions in highly available systems.
Innovation Solution
A shuttle valve design that selects maximum pressure from two separate control pressure lines, incorporating a first and second inlet pressure port for each control pressure, with valve bodies having different surface areas and a mechanical coupling mechanism to ensure one functional directional valve can maintain control authority, even if another fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two directional valves are used in parallel for redundant control of a double-acting cylinder, then system reliability is improved, but full functionality cannot be maintained when one valve fails because full supply pressure flows into the non-functional control line
Solution Approach 1:
The control pressure lines are segmented into separate pathways through the shuttle valve mechanism. Each directional valve controls its own dedicated control pressure line (first control pressure line 1 and second control pressure line 2), preventing pressure interference between redundant channels. This segmentation allows independent operation and maintenance of each valve while preserving overall system functionality.
Solution Approach 2:
The shuttle valve acts as an intermediary component between the two directional valves and the double-acting cylinder. It mediates the control pressure from both valves, selecting and directing appropriate pressure to each side of the cylinder piston. This intermediary mechanism prevents full supply pressure from flowing into non-functional lines while maintaining controlled pressure regulation.
2Device complexity
If a traditional shuttle valve combines two control pressures into a shared line, then device complexity is reduced, but control precision is lost because maximum pressure selection prevents independent control of opposite piston sides
Solution Approach 1:
Instead of combining both control pressures into a single shared line, the invention segments the control pressure pathways into separate lines (first control pressure line 1 and second control pressure line 2). Each line independently controls one side of the piston, enabling precise pressure control on each side while maintaining relatively simple device structure through the shuttle valve mechanism.
3Force
If the first control pressure acts on a larger surface area than the second control pressure, then the first directional valve has greater influence on the shuttle valve position, but this creates asymmetry in the control system
Solution Approach 1:
The invention deliberately employs asymmetric valve body surface areas (first valve body 17 with larger surfaces F1, F2 compared to second valve body 18 with smaller surfaces F3, F4) to create differential control authority. This asymmetry allows the first directional valve to have greater influence on shuttle valve positioning when needed, providing flexible and adaptable control characteristics for different operating conditions.
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
Ensures continuous operation of actuators by preventing the full supply pressure from flowing into non-functional control lines, allowing the operational shuttle valve to maintain control pressure regulation.
Implementation Method 1
The first control pressure from the first inlet pressure port 11 is applied to a first side A1 of the first valve body 17, and the first control pressure from the second inlet pressure port 12 is applied to a second side A2 situated opposite the first side. The second control pressure from the third inlet pressure port 13 is applied to a first side B1 of the second valve body 18, and the second control pressure from the fourth inlet pressure port 14 is applied to a second side B2 situated opposite the first side.
Implementation Method 2
The first control pressure acts on each of a first and second control-pressure-charged surface F1, F2 of the first valve body 17, and the second control pressure acts on each of a third and fourth control-pressure-charged surface F3, F4 of the second valve body 18.
Data Source
AI summary
A shuttle valve includes: a first valve body; a second valve body, a first control-pressure-charged surface and a second control-pressure-charged surface of the first valve body being larger than a third control-pressure-charged surface and a fourth control-pressure-charged surface of the second valve body, a first control pressure from a first inlet pressure port being applied to a first valve body first side, the first control pressure from a second inlet pressure port being applied to a first valve body second side, a second control pressure from a third inlet pressure port being applied to a second valve body first side, the second control pressure from a fourth inlet pressure port being applied to a second valve body second side, a first control pressure acting on a first control-pressure-charged surface and a second control-pressure-charged surface, and the second control pressure acting on a third control-pressure-charged surface and a fourth control-pressure-charged surface.