Coupled Shuttle Valve Failover for Redundant Cylinder Pressure Control
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Solution Overview
Problem
Existing hydraulic systems with directional control modules fail to maintain full functionality of actuators, particularly double-acting cylinders, when a directional control valve fails, necessitating manual intervention to restore operation.
Innovation Solution
A changeover valve design with two inlet and two outlet pressure ports, featuring valve bodies with pressure-sensitive surfaces of unequal areas, mechanically coupled to ensure continuous control pressure regulation even in the event of a directional control valve failure, using a coupling element to maintain sealing and pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two directional control valves are used in parallel for redundant control of a double-acting cylinder, then system reliability is improved, but the changeover valve cannot maintain full functionality when one valve fails because full supply pressure acts on both changeover valves simultaneously
Solution Approach 1:
The patent applies asymmetry by making the pressure-sensitive surfaces of the first and second valve bodies unequal in area. Specifically, the first pressure-sensitive surface (F1) is larger than the second pressure-sensitive surface (F2). This asymmetric design creates a force imbalance that automatically favors one control pressure line over the other, enabling the functional valve to maintain control even when the other valve fails and supplies full pressure.
2Reliability
If two changeover valves are provided for redundant control pressure supply to a double-acting cylinder, then redundancy is improved, but the maximum pressure from a defective valve always prevails causing the piston to move to one end position
Solution Approach 1:
The patent applies the counterweight principle by using the force generated on the smaller pressure-sensitive surface (F2) to counterbalance and overcome the full supply pressure acting on the larger pressure-sensitive surface (F1) when a valve fails. This force counteraction prevents the defective valve's maximum pressure from dominating, allowing the functional valve to maintain precise pressure control.
3Ease of manufacture
If directional control valves are designed with equal pressure-sensitive areas, then manufacturing simplicity is improved, but automatic pressure regulation fails when one valve fails because there is no force imbalance to prevent full pressure from acting on the actuator
Solution Approach 1:
The patent deliberately introduces asymmetry in the pressure-sensitive surface areas to resolve the contradiction between manufacturing simplicity and failover functionality. The unequal areas (F1 > F2) create an inherent force imbalance that automatically enables the functional valve to override any full pressure from a defective valve, providing reliable automatic failover without complex control systems.
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 uninterrupted operation of actuators by automatically switching to a functional directional control valve, preventing pressure loss and enabling continuous actuation without manual intervention.
Implementation Method 1
The first valve body (17) is subjected on a first side (A1) to a first control pressure (p1) from the first inlet pressure port (11) and on a second side (A2) opposite to this to a first control pressure (p1) from the second inlet pressure port (12). The second valve body (18) is subjected on a first side (B1) to a second control pressure (p2) from the third inlet pressure port (13) and on a second side (B2) opposite to this to a second control pressure (p2) from the fourth inlet pressure port (14).
Implementation Method 2
The two valve bodies (17, 18) are mechanically coupled to one another in such a way that they always move together to either fully or partially seal or open the first and third inlet pressure ports (11, 13) or the second and fourth inlet pressure ports (12, 14).
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a shuttle valve for selecting a maximum pressure in two mutually separate control pressure lines; having a first inlet pressure port and a second inlet pressure port for a first control pressure; having a third inlet pressure port and a fourth inlet pressure port for a second control pressure; having a first outlet pressure port for connecting to the first control pressure line and having a second outlet pressure port for connecting to the second control pressure line; having a first valve element fluidically connected between the first and the second inlet pressure port, on the one hand, and the first outlet pressure port, on the other hand, and having a second valve element between the third and the fourth inlet pressure port, on the one hand, and the second outlet pressure port, on the other hand; wherein the first control pressure from the first inlet pressure port acts on a first side of the first valve element and the first control pressure from the second inlet pressure port acts on a second side, situated opposite said first side, of the first valve element, and the second control pressure from the third inlet pressure port acts on a first side of the second valve element and the second control pressure from the fourth inlet pressure port acts on a second side, situated opposite said first side, of the second valve element; wherein the first control pressure acts on each of a first and a second control-pressure-charged surface of the first valve element, and the second control pressure acts on each of a third and a fourth control-pressure-charged surface of the second valve element, the first and the second control-pressure-charged surface are larger than the third and the fourth control-pressure-charged surface, and the first valve element and the second valve element are positively coupled for conjoint movement.