Hydraulic Valve Flow Segmentation for Precise Actuator Control
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Solution Overview
Problem
Conventional hydraulic systems for working machines, such as skid steer loaders, face issues with horsepower loss and difficulty in precisely operating hydraulic actuators due to variable fluid flow rates, leading to overheating and inefficient operation.
Innovation Solution
A hydraulic system with a variable displacement pump and multiple control valves that include flowrate reduction and increase sections, allowing for precise control of fluid flow to actuators, minimizing horsepower loss and enabling efficient cooling of hydraulic fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic fluid flowrate is increased rapidly to supply large amount of hydraulic fluid to hydraulic actuator, then productivity is improved, but measurement precision deteriorates making precise operation difficult
Solution Approach 1:
The control valve is divided into multiple positions (first position, second position, third position) with different flow control characteristics. The first position provides flowrate reduction for precise operation, the second position provides maximum flowrate for rapid operation, and the third position provides intermediate flowrate. This segmentation allows the system to select appropriate flow control modes based on operational requirements.
Solution Approach 2:
The control valve spool can be dynamically positioned among multiple positions to change the flow control characteristics in real-time. The spool position is adjusted based on operational needs, allowing transition from precise flow control (first position) to rapid flow supply (second position) as required.
2Adaptability or versatility
If variable displacement hydraulic pump is operated to make flowrate variable while keeping LS differential pressure constant, then adaptability is improved, but loss of energy increases due to horsepower loss
Solution Approach 1:
The control valve is segmented into multiple positions that provide different flow control characteristics. This allows the system to operate in different modes: precise operation mode (first position), rapid operation mode (second position), and intermediate mode (third position), thereby adapting to various operational requirements without excessive energy loss.
Solution Approach 2:
The system changes the flow control parameters by shifting the control valve spool among different positions. This parameter change allows the system to optimize the balance between flowrate and energy consumption based on the specific operational task at hand.
3Productivity
If hydraulic fluid is increased rapidly to supply large amount of hydraulic fluid, then productivity is improved, but temperature increases causing hydraulic fluid to become hot
Solution Approach 1:
The control valve is divided into multiple positions with different flow control characteristics. The first position reduces flowrate for precise operation and lower heat generation, the second position provides maximum flowrate for rapid operation, and the third position provides intermediate flowrate. This segmentation allows operators to select the appropriate position based on whether precision or speed is the priority, thereby managing heat generation.
Solution Approach 2:
The control valve provides partial flowrate reduction at the first position, which is sufficient for precise operation without requiring maximum flowrate. This partial action approach reduces unnecessary energy consumption and heat generation while still achieving the desired operational precision.
Data Source
AI summary
A hydraulic system for a working machine includes hydraulic actuators actuated with hydraulic fluid delivered from a hydraulic pump, and control valves each of which is shiftable among shift positions to control a flowrate of hydraulic fluid flowing to the corresponding hydraulic actuator. Each control valve includes an input port, an output port, and a flowrate reduction section. When the control valve is shifted to a reduction position, the flowrate reduction section reduces a flowrate of the hydraulic fluid entering the input port and outputs the flowrate-reduced hydraulic fluid to the output port. At least one of the control valves includes a flowrate increase section. When the control valve is shifted to an increase position, the flowrate increase section outputs the hydraulic fluid having entered the input port to the output port at a flowrate larger than that of hydraulic fluid output by the flowrate reduction section.