Hydraulic Spool Assembly with Separated Inserts
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Solution Overview
Problem
Conventional hydraulic spools in metering valves are massive and require significant energy to move, leading to slow responses and the need for additional components to offset these issues, which can result in system delays and increased size.
Innovation Solution
A spool assembly with a cylindrical body and separate inserts at each end, featuring radially oriented orifices and lands that define an open axial space, allowing for reduced mass and energy consumption, and a feedback element with a conical ramp to facilitate faster movement and increased responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional solid spool is used in a metering valve, then the valve structure is simple and robust, but the spool mass is large requiring significant energy to move and resulting in slow response
Solution Approach 1:
The spool is divided into a hollow cylindrical body and separate insert elements (land inserts, seal inserts, orifice inserts) that can be independently positioned or removed. This segmentation reduces the effective moving mass while maintaining the functional integrity of the spool assembly, thereby reducing energy requirements for movement and improving response speed.
Solution Approach 2:
The spool design extracts the functional elements (lands, seals, orifices) from a solid monolithic structure and positions them as separate inserts within a hollow cylindrical body. This extraction eliminates unnecessary material mass while preserving the essential flow control functions, directly addressing the energy and speed contradiction.
2Use of energy by moving object
If a hollow spool with internal block is used to reduce mass, then the spool mass is reduced, but the internal block axially displaces oil during movement requiring significant energy and causing system delay
Solution Approach 1:
The harmful internal block that caused oil displacement and system delay is completely removed from the hollow spool design. The functional elements are achieved through separate inserts positioned within the hollow body, eliminating the source of the time loss problem while maintaining the mass reduction benefit.
Solution Approach 2:
Instead of a uniform hollow spool design, the patent applies local quality by positioning specific functional inserts (lands, seals, orifices) at precise locations within the hollow body. This allows the spool to maintain minimal mass while achieving the necessary flow control functions without displacing oil during movement.
3Speed
If the spool mass is reduced to improve responsiveness, then the energy required to move the spool is reduced, but the spool may become too small to internally accommodate the required fluid volume
Solution Approach 1:
The patent nests multiple functional inserts (land inserts, seal inserts, orifice inserts) within the hollow cylindrical spool body. This nesting arrangement allows the spool to maintain a compact external dimension for responsiveness while internally accommodating sufficient fluid volume through the hollow cavity and insert configurations.
Solution Approach 2:
The patent utilizes the radial dimension by positioning orifices and flow paths in the wall thickness of the hollow spool body rather than relying solely on axial volume. This dimensional approach allows adequate fluid accommodation in a compact spool design that maintains responsiveness.
Data Source
AI summary
A spool assembly is disclosed for use in a valve. The spool assembly may have a cylindrical body with a first end, a second end, and a bore passing from the first end through the second end. The spool assembly may also have a first insert with a first land slidably disposed inside the bore at the first end, and a second insert separate from the first insert. The second insert may have a second land slidably disposed inside the bore at the second end.