Electro-Hydraulic Pump Control Fail-Safe Mechanism
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Solution Overview
Problem
Existing control schemes for variable displacement hydraulic pumps do not automatically fail to a neutral position upon loss of power, which can lead to unintended operation and reduced safety in hydraulic systems.
Innovation Solution
A fail-safe electro-hydraulic control system is implemented, utilizing a drain valve and pressure chambers to automatically return the swashplate to a neutral position by de-energizing control valves and allowing fluid flow to the tank, ensuring the system resets to a stable state even without power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional control scheme is used for the variable displacement pump, then the system can operate with standard control mechanisms, but the system fails to automatically return to a neutral position upon power loss, leading to safety issues and unintended operation
Solution Approach 1:
The control system is designed with a fail-safe mechanism that automatically returns the swashplate to a neutral position upon power loss. The drain valve is configured to open automatically when power is lost, allowing fluid to drain from the actuator and return the swashplate to neutral, preventing unintended operation and ensuring safety without requiring complex additional components
Solution Approach 2:
The system uses the loss of power itself as the triggering mechanism for the fail-safe action. When power is lost, the electrical device automatically de-energizes, causing the drain valve to open and the swashplate to return to neutral position without requiring any additional sensors, actuators, or control logic, making the system self-regulating in failure conditions
2Stability of the object's composition
If the drain valve is kept closed during normal operation, then fluid flow to the tank is restricted maintaining system pressure, but upon power loss the system cannot automatically reset to a stable neutral state
Solution Approach 1:
The drain valve is pre-configured with a spring mechanism that automatically opens it upon de-energization. This preliminary setup ensures that when power is lost, the valve automatically opens to allow fluid drainage and return the swashplate to neutral position, providing automatic reset capability without requiring manual intervention or complex control logic
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
The system effectively ensures the swashplate returns to a neutral position upon power loss, maintaining system stability and safety by preventing unintended operation and ensuring minimal displacement of the primary pump.
Implementation Method 1
fluid is passable from both the first orifice and the second orifice to the tank when the drain valve is in the open position
Implementation Method 2
fluid is restricted from passing from both the first orifice and the second orifice to the tank when the drain valve is in the closed position
Data Source
AI summary
An electro-hydraulic control system for pump control is disclosed. The hydraulic actuator is configured to control the inclination of a swashplate. The position of the hydraulic actuator is controlled by controlling the flow of pressurized fluid into and out of two pressure chambers, one on either side of the actuator. A fluid passageway is provided that selectively connects the passageway to tank. The passageway has an orifice for each pressure chamber, and the actuator is configured to selectively block all or a portion of one or more of the orifices, depending on the position of the actuator. The components of the control system are configured such that the actuator will return to a neutral or near-neutral position upon loss of electric power.