Excavator Boom Hydraulic Flow Control for Load-Accurate Bucket Motion
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Solution Overview
Problem
Existing hydraulic drive apparatuses for excavation machines face challenges in accurately controlling the speed of the boom due to varying loads, affecting the precise movement of the bucket along a target locus and the applied compression force.
Innovation Solution
A hydraulic drive apparatus with a boom flow rate control valve that adjusts the supply and discharge flow rates of hydraulic oil based on the direction of the target boom cylinder speed relative to the cylinder thrust, using a boom flow rate operation part to ensure accurate control of the boom cylinder speed, regardless of the load acting on it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional hydraulic control is used to drive the boom cylinder, then the system is simple to operate, but the boom speed control accuracy deteriorates due to varying loads
Solution Approach 1:
The control system continuously monitors the actual boom cylinder speed and compares it with the target speed, then adjusts the supply flow rate dynamically based on the speed deviation. This closed-loop feedback mechanism ensures accurate boom speed control despite varying loads, directly resolving the contradiction between control accuracy and system simplicity.
Solution Approach 2:
The patent replaces conventional mechanical hydraulic control with an electronically controlled variable displacement pump system. The pump's displacement is automatically adjusted based on detected boom cylinder speed, eliminating the need for complex manual control mechanisms while achieving precise speed regulation under varying load conditions.
2Manufacturing precision
If the boom cylinder speed is not accurately controlled, then the control system is simple, but the manufacturing precision of the construction surface deteriorates
Solution Approach 1:
The system uses feedback control where the actual boom cylinder speed is continuously detected and compared with the target speed. The variable displacement pump adjusts its supply flow rate based on this speed deviation, ensuring the boom moves at the precise speed needed to maintain the construction surface within the desired positional deviation from the target surface.
Solution Approach 2:
The patent changes the supply flow rate parameter dynamically by adjusting the variable displacement pump's displacement based on the detected boom cylinder speed. This parameter adjustment ensures that the boom speed remains accurate despite load variations, thereby maintaining construction surface precision without requiring overly complex control mechanisms.
3Ease of operation
If automatic control function is added to reduce operator burden, then ease of operation improves, but device complexity increases
Solution Approach 1:
The control system automatically detects the boom cylinder speed and adjusts the supply flow rate without requiring continuous manual intervention from the operator. The variable displacement pump self-regulates based on feedback signals, reducing the operator's burden while maintaining precise control, thus balancing ease of operation with acceptable system complexity.
4Productivity
If the supply flow rate is not dynamically adjusted, then the control system is simpler, but the productivity deteriorates due to inaccurate boom speed control
Solution Approach 1:
The system continuously detects the boom cylinder speed and uses this feedback to dynamically adjust the supply flow rate via the variable displacement pump. This ensures the boom maintains the optimal speed for excavation work, improving productivity by preventing both slow operation and excessive speed that could compromise precision, while keeping the control system manageable through automated feedback control.
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
This solution enables high-accuracy control of the boom movement, ensuring the construction surface formed by the bucket is closer to the target surface, regardless of the load, thereby improving the precision of the bucket's movement and compression force application.
Implementation Method 1
a hydraulic pump that is driven by a driving source to discharge hydraulic oil; a boom cylinder that is expanded and contracted by supply of hydraulic oil from the hydraulic oil supply device
Implementation Method 2
a boom flow rate control valve interposed between the hydraulic oil supply device and the at least one boom cylinder and capable of performing opening and closing motions to change a boom cylinder supply flow rate which is a flow rate of hydraulic oil supplied from the hydraulic oil supply device to the at least one boom cylinder
Data Source
AI summary
A hydraulic drive apparatus includes a boom flow rate control valve, a target boom cylinder speed calculation part calculating a target boom cylinder speed for making a construction surface by a bucket closer to a target construction surface based on the cylinder speed of a boom cylinder and the like, and a boom flow rate operation part. The boom flow rate operation part operates the boom flow rate control valve to make a boom cylinder supply flow rate be a target supply flow rate corresponding to the target boom cylinder speed when the target boom cylinder speed direction coincides with a cylinder thrust direction, and operates the boom flow rate control valve to make the boom cylinder discharge flow rate be a target discharge flow rate corresponding to the target boom cylinder speed when the target boom cylinder speed direction is opposite to the cylinder thrust direction.