Spool Valve Independent Flow Control via Segmented Notches
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Solution Overview
Problem
Existing spool valves cannot individually control the flow rate and pressure of working fluid between a pump and a cylinder, and between a cylinder and a tank, leading to inefficient fuel usage and operational limitations in construction equipment.
Innovation Solution
A spool valve design featuring multiple independently movable spools with notches and pilot pressure control, allowing for separate management of flow rates and pressures between pump-cylinder and cylinder-tank paths, enabling precise control based on cylinder operations and loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spool with notches is used to control both pump-cylinder and cylinder-tank paths, then the device complexity is reduced, but the ability to individually control flow rates and pressures is lost
Solution Approach 1:
The single spool is divided into multiple independent spools (first spool for pump-cylinder path, second spool for cylinder-tank path). Each spool can be controlled independently by its own pilot pressure, allowing separate control of flow rates and pressures for each fluid path. This segmentation resolves the contradiction by sacrificing some structural simplicity to gain independent control capability.
2Device complexity
If the same area of opening is applied to both pump-cylinder and cylinder-tank paths, then the spool structure is simplified, but fuel efficiency deteriorates due to inability to individually control flow rates and pressures
Solution Approach 1:
Each spool is equipped with its own pilot pressure control system that can independently adjust the opening area of its respective path. The first spool's opening area for pump-cylinder path and the second spool's opening area for cylinder-tank path can be independently optimized based on actual operational requirements, enabling energy-efficient control for each path while maintaining structural simplicity.
3Adaptability or versatility
If independent spools with separate pilot pressure control are used for each path, then flow rate and pressure control capability is improved, but device complexity increases
Solution Approach 1:
The control system is segmented into independent spool units, each with its own pilot pressure control. This modular segmentation allows each spool to be controlled independently while maintaining overall system manageability, balancing the need for independent control capability with acceptable device complexity.
Data Source
Figure 1~2
AI summary
The present invention provides a spool valve, comprising: a valve block; a first spool, which is mounted onto one side on the inside of the valve block so as to be moved forward and backward in the lengthwise direction and comprises a first notch formed on the outer circumferential surface, for controlling the connection between a first pump flow path and a first cylinder flow path through the first notch which is aligned with the first pump flow path and the first cylinder flow path formed on the inside of the valve block, when moved according to a change in stroke; and a second spool, which is mounted onto the other side on the inside of the valve block so as to be moved forward and backward in the lengthwise direction and comprises a second notch formed on the outer circumferential surface, for controlling the connection between a second cylinder flow path and a first tank flow path through the second notch which is aligned with the second cylinder flow path and the first tank flow path formed on the inside of the valve block, when moved according to a change in stroke.