Hydraulic Excavator Valve Control for Swing Torque and Actuator Speed
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Solution Overview
Problem
Existing control circuits for hydraulic excavators face challenges in efficiently controlling the speed of actuators and torque of swing motors during combined operations, due to interference between meter-in and meter-out opening controls and increased complexity and cost.
Innovation Solution
The proposed work machine incorporates a hydraulic system with directional control valves that use the same valve disc for meter-in and meter-out openings, controlled by a sophisticated controller that calculates target flow rates and opening areas based on operational inputs and sensor data, allowing for independent regulation of actuator speed and swing motor torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one spool valve is used to execute both meter-in opening control and meter-out opening control, then the circuit complexity is reduced, but the relationship between meter-in opening area and meter-out opening area becomes fixed and cannot be adjusted according to different work conditions
Solution Approach 1:
The invention divides the control functions into separate components: a directional control valve for flow direction switching and a flow control valve for adjustable flow rate control. This segmentation allows independent optimization of each function, enabling the meter-in and meter-out opening areas to be adjusted independently according to different work conditions while maintaining a relatively simple circuit structure.
2Adaptability or versatility
If four metering valves are used to execute fluid feed/discharge control, then the adaptability to different work conditions is improved, but the number of parts and circuit complexity increase
Solution Approach 1:
The invention combines the directional control function and flow control function into a unified flow control valve assembly that works cooperatively with the directional control valve. This merging reduces the total number of valves from four to two while maintaining the ability to adapt to different work conditions through adjustable opening areas, thereby simplifying the circuit without sacrificing versatility.
3Device complexity
If meter-in opening control and meter-out opening control are executed by one directional control valve, then the circuit is simplified, but the controls interfere with each other and operability decreases
Solution Approach 1:
The invention separates the directional control function and flow control function into distinct valves: the directional control valve handles flow direction switching while the flow control valve manages flow rate control with adjustable opening areas. This functional segmentation eliminates interference between meter-in and meter-out controls, improving operability while maintaining circuit simplicity through coordinated operation of the two valves.
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 configuration enables efficient speed control of actuators and torque control of swing motors during combined operations, preventing overrun and ensuring precise control with a simpler system configuration, thereby improving operational efficiency and reducing costs.
Implementation Method 1
a hydraulic pump of a variable displacement type that sucks in a hydraulic operating fluid from the hydraulic operating fluid tank and delivers the hydraulic operating fluid
Implementation Method 2
an actuator directional control valve that controls the flow of a hydraulic fluid supplied from the hydraulic pump to the actuator, and a swing directional control valve that controls the flow of the hydraulic fluid supplied from the hydraulic pump to the swing motor
Data Source
AI summary
The present invention intends to provide a work machine that can execute speed control of an actuator and torque control of a swing motor by a simple configuration at the time of combined operation to simultaneously drive the swing motor and the other actuator. For this purpose, a controller calculates a pump target flow rate on the basis of an actuator target flow rate and a swing target flow rate and calculates a target meter-in opening area of an actuator directional control valve on the basis of the actuator target flow rate, a pump pressure, and an actuator meter-in pressure. The controller calculates target torque of the swing motor on the basis of the input amount of operation devices and output values of posture sensors and calculates a swing target meter-out pressure on the basis of the target torque and a swing meter-in pressure. The controller calculates a target meter-out opening area of a swing directional control valve on the basis of the swing target meter-out pressure and a swing meter-out pressure.