Excavator Relief Pressure Control for High-Load Digging Power
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Solution Overview
Problem
Hydraulic excavators lack the ability to effectively increase power during high excavation load operations, leading to inefficient excavation control.
Innovation Solution
A work machine equipped with a hydraulic cylinder, hydraulic pump, relief valve, state determination unit, detection unit, and relief pressure changing unit that adjusts relief pressure based on hydraulic oil pressure and implement speed to enhance power during excavation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If relief pressure is increased to boost power during hoisting and swinging operations, then power for those operations is improved, but excavation control under high load deteriorates
Solution Approach 1:
The relief valve pressure is made dynamically adjustable based on the detected work state. The control unit changes the relief valve pressure between a first value (for excavation) and a second value higher than the first (for hoisting/swinging), allowing the system to adapt pressure settings to current operational needs rather than using a fixed high pressure setting
Solution Approach 2:
The system changes the relief valve pressure parameter according to the detected controlled state. When the state determination unit detects hoisting or swinging operations, the control unit increases the relief valve pressure to the second value, thereby optimizing power delivery for those specific operations while maintaining proper excavation control during excavation states
2Power
If relief pressure is increased to increase hydraulic system power, then overall system power is improved, but excavation with high excavation load cannot be normally controlled
Solution Approach 1:
The relief valve pressure is dynamically adjusted based on real-time detection of the work implement's controlled state. The control unit switches between a lower first relief pressure value (maintaining excavation controllability) and a higher second relief pressure value (providing increased hydraulic power), ensuring the appropriate pressure level is applied for the current operational context
Solution Approach 2:
The system modifies the relief valve pressure parameter according to the detected state. When hoisting or swinging operations are detected, the relief pressure is increased to the second value to enhance hydraulic power. During excavation operations, the relief pressure is maintained at the first value to preserve precise excavation control and responsiveness
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 increases power during high excavation load operations, improving the control and efficiency of the excavation process.
Implementation Method 1
a relief valve that can set a relief pressure of the hydraulic circuit to either a first set pressure or a second set pressure higher than the first set pressure
Implementation Method 2
a hydraulic pump that supplies the hydraulic oil to the hydraulic cylinder via a hydraulic circuit
Data Source
AI summary
A work machine comprises: a work implement; a hydraulic cylinder; a hydraulic pump that supplies the hydraulic oil to the hydraulic cylinder via a hydraulic circuit; a relief valve that can set a relief pressure of the hydraulic circuit to either a first set pressure or a second set pressure higher than the first set pressure; a detection unit that detects at least one of a pressure of the hydraulic oil in the hydraulic circuit and a speed of the work implement; and a relief pressure changing unit that changes a relief pressure of the relief valve from the first set pressure to the second set pressure based on a detection value of at least one of the pressure of the hydraulic oil in the hydraulic circuit and the speed of the work implement when the controlled state of the work implement is the excavation state.