Hydraulic Valve Spool Geometry for Precise Flow and Rigidity
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Solution Overview
Problem
Hydraulic valves face challenges in fine flow rate control due to increased inner diameter of the main passage, which compromises spool rigidity and leads to deformation under high hydraulic pressure, and air bubbles can cause erosion and sealability issues.
Innovation Solution
A hydraulic valve design with a spool featuring a large-diameter first passage region, a tapered third region connecting to a smaller-diameter second region, and strategically placed sub-passages to minimize flow force influence and air bubble accumulation, ensuring accurate flow rate control and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the inner diameter of the main passage is increased to provide a large number of sub-passages for fine flow rate control, then the flow force influence is reduced, but the spool rigidity deteriorates causing deformation under high hydraulic pressure
Solution Approach 1:
The spool is designed with non-uniform wall thickness where the first region (with sub-passages) has a larger inner diameter to reduce flow force, while the second region maintains a smaller inner diameter to preserve rigidity. This local differentiation allows each region to optimize for its specific function without compromising the other.
Solution Approach 2:
The spool is divided into multiple regions along the axial direction: a first region with a larger inner diameter containing sub-passages for flow control, and a second region with a smaller inner diameter for rigidity. This segmentation allows independent optimization of flow characteristics and structural strength in different sections.
2Manufacturing precision
If the inner diameter of the main passage is increased to accommodate multiple sub-passages, then fine flow rate control is achieved, but the spool deforms under high hydraulic pressure
Solution Approach 1:
The spool structure implements local quality by having different inner diameters in different axial regions. The first region has a larger diameter to enable precise flow rate control through multiple sub-passages, while the second region maintains a smaller diameter to ensure shape stability under high pressure, preventing deformation that would compromise control precision.
3Reliability
If air bubbles are generated in oil flowing from the first port, then they may accumulate in the first region or reach the valve main body causing erosion, but the tapered third region design prevents this
Solution Approach 1:
The third region is designed with a tapered shape that creates a smooth curvature transition between the first and second regions. This curved geometry guides oil flow smoothly, preventing turbulence and air bubble accumulation, while also directing bubbles away from the valve main body to prevent erosion and improve reliability.
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
The design allows for precise flow rate control and prevents air bubble-induced erosion, maintaining spool rigidity and sealability, enhancing operational accuracy and reliability.
Implementation Method 1
the third region being formed in a tapered shape in which an inner diameter gradually decreases toward the second region... the oil smoothly passes through the third region, reaches the second region without being reversed
Data Source
AI summary
A hydraulic valve includes: a valve main body; and a spool. Further, the spool is provided with a main passage portion, a first passage portion communicable with a first port, and a second passage portion communicable with a second port, an opening area of the first passage portion with respect to the first port is changed and flow rate control of oil from the first port to the second port through the main passage portion is performed, and the main passage portion of the spool has a first region, a second region, and a third region that connects the first region and the second region, an inner diameter of the first region being formed larger than that of the second region, and the third region being formed in a tapered shape in which an inner diameter gradually decreases toward the second region.