Hydraulic Actuator Mode Switching for Speed-Load Balance
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Solution Overview
Problem
Hydraulic actuators operating in differential mode face limitations in maximum load handling due to the volume imbalance between the first and second actuator chambers, which affects the flowrate of hydraulic fluid and efficiency of energy transfer.
Innovation Solution
A controller is introduced to dynamically manage the fluid connections between the actuator chambers and the hydraulic machine, allowing for mode changes between normal and differential operation by adjusting the flowrate of hydraulic fluid, thereby optimizing the movement and load handling capacity of the hydraulic actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the hydraulic actuator operates in differential mode with the first actuator chamber fluidly connected to both the hydraulic machine and the second actuator chamber, then the speed of the hydraulic actuator is improved, but the maximum load handling capacity deteriorates
Solution Approach 1:
The system dynamically switches between normal mode and differential mode based on operational requirements. The controller activates the connection between the first actuator chamber and the second actuator chamber to enable differential mode for speed-intensive operations, and deactivates it for load-intensive operations, making the system's fluid connection configuration changeable rather than fixed
Solution Approach 2:
The controller changes the flow rate parameter of the hydraulic machine when transitioning between operating modes. When switching from normal mode to differential mode, the controller adjusts the flow rate to compensate for the volume imbalance between actuator chambers, ensuring smooth operation and preventing fluid starvation or excessive pressure buildup
2Productivity
If the volume of the first actuator chamber decreases in differential mode, then the flowrate of hydraulic fluid through the hydraulic machine is improved, but the volume imbalance between chambers causes inefficiency in energy transfer
Solution Approach 1:
The controller monitors the operating conditions and provides feedback to adjust the flow rate of the hydraulic machine. When differential mode is activated, the controller detects the volume imbalance between chambers and adjusts the flow rate accordingly to maintain efficient energy transfer, preventing energy loss due to improper fluid distribution
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 controller enables efficient operation by ensuring smooth transitions between normal and differential modes, enhancing the load handling capacity and energy transfer efficiency of the hydraulic actuator, particularly in vehicles like wheel loaders.
Implementation Method 1
the hydraulic machine exchanges energy with the hydraulic circuit and the prime mover by movement hydraulic fluid between the hydraulic machine and the hydraulic circuit
Implementation Method 2
a valve arrangement in the hydraulic circuit for selectively routing the hydraulic fluid between the first actuator chamber and one or more of: the hydraulic machine; and the second actuator chamber
Data Source
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AI summary
The present invention provides a controller for a hydraulic apparatus. The controller is configured to determine (410) that a mode change criteria has been met for the hydraulic apparatus. In response to the determination, the controller is configured to control (420) a valve arrangement to change a first actuator chamber of a hydraulic actuator between being fluidly connected to a hydraulic machine and fluidly isolated from a second chamber of the hydraulic actuator, and being fluidly connected to both the second actuator chamber and the hydraulic machine. Further in response to the determination, the controller is configured to control (430) the hydraulic machine to change a flow rate of hydraulic fluid flowing through the hydraulic machine to regulate a movement of the hydraulic actuator during the control of the valve arrangement.