Dual Spool Flow Control Valve for Excavator Hydraulic Cylinders
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Solution Overview
Problem
Existing hydraulic control systems for excavators require manual skill to adjust flow rates due to equal supply and discharge flow rates, leading to poor reproducibility and responsiveness, and increase in valve block size with separate flow control valves for each hydraulic cylinder.
Innovation Solution
A flow control valve apparatus with two spools and actuators that independently control supply and discharge flow rates, arranged in a single spool hole to minimize size and interference, with biasing mechanisms for fail-safe operation and accurate flow rate adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate flow control valves are provided for head-side port and rod-side port, then independent control of supply and discharge flow rates is achieved, but the valve block size increases
Solution Approach 1:
The patent combines two separate flow control valves (for head-side port and rod-side port) into a single integrated flow control valve apparatus. This single valve block contains multiple spools (first spool for head-side control, second spool for rod-side control) that operate independently within the same valve body, achieving independent flow rate control for both ports while maintaining a compact size and avoiding the need for separate valve blocks.
Solution Approach 2:
The single flow control valve apparatus is designed to perform multiple functions simultaneously - it controls both the head-side port flow rate and the rod-side port flow rate through different spools within the same valve body. This multi-functional design eliminates the need for separate dedicated valves for each port, reducing overall system size while maintaining independent control capabilities.
2Device complexity
If one spool controls both supply and discharge flow rates, then device complexity is reduced, but reproducibility and responsiveness deteriorate due to skill-dependent manipulation
Solution Approach 1:
The patent segments the control function by providing separate spools for different control tasks - the first spool controls the head-side port flow rate while the second spool controls the rod-side port flow rate. Each spool can be independently actuated by its own actuator, enabling precise and reproducible control of each flow rate without requiring skilled manual manipulation of a single combined spool.
Solution Approach 2:
The patent incorporates actuators that can be controlled based on feedback signals to automatically adjust spool positions and maintain desired flow rates. This feedback control mechanism eliminates the need for skill-dependent manual manipulation, ensuring consistent reproducibility and responsiveness while maintaining relatively simple device architecture.
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
Enables independent control of supply and discharge flow rates for each hydraulic cylinder, reducing the size of the valve block and improving reproducibility and responsiveness, while ensuring fail-safe operation and accurate flow rate adjustment.
Implementation Method 1
electromagnetic solenoids are provided at respective end portions of the spool. Each electromagnetic solenoid can push the corresponding end portion of the spool to move the spool
Data Source
AI summary
A flow control valve apparatus includes: a housing including two pump ports, two tank ports, a first supply/discharge port, a second supply/discharge port, and a spool hole; a first spool configured to switch a connection status among one of the pump ports, one of the tank ports, and the first supply/discharge port depending on a position of the first spool; a first actuator configured to move the first spool to each of a first supply position and a first discharge position; a second spool configured to switch a connection status among the other pump port, the other tank port, and the second supply/discharge port depending on a position of the second spool; and a second actuator configured to move the second spool to each of a second supply position and a second discharge position. The first spool and second spool are inserted in the spool hole so as to reciprocate.