Valve End Cap Retention Using Rotating Groove Locking
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Solution Overview
Problem
The assembly and retention of end caps in spool valves, such as servovalves, are costly and time-consuming due to the use of substantial endplates under high pressure, which also add weight to the valve, particularly problematic in applications like aircraft.
Innovation Solution
A valve assembly with a circumferentially extending groove in the valve housing and an end cap featuring radially outwardly extending retaining elements that align with axial slots to prevent axial withdrawal, combined with an anti-rotation element and locking mechanism to secure the end cap without the need for heavy endplates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substantial endplates bolted by multiple bolts are used to retain end caps under high pressure, then the end caps are securely retained, but the valve weight increases considerably and the assembly becomes costly and time-consuming
Solution Approach 1:
The end cap is divided into two functional parts: a retaining portion with radially outwardly extending retaining elements that engage with axial slots in the groove, and a head portion that closes the bore. This segmentation allows the end cap to be retained without requiring substantial endplates, significantly reducing valve weight while maintaining secure retention under high pressure.
Solution Approach 2:
The retaining mechanism transitions from a planar bolted connection to a three-dimensional engagement system. The radially outwardly extending retaining elements are inserted into axial slots and then rotated within the circumferentially extending groove, creating a multi-dimensional retention mechanism that provides secure holding without the need for heavy endplates.
2Reliability
If substantial endplates with multiple bolts are used to retain end caps, then the end caps are securely retained under high pressure, but the assembly process becomes costly and time-consuming
Solution Approach 1:
The end cap's retaining portion is segmented with multiple radially outwardly extending retaining elements that can be independently inserted into axial slots. This allows for a simpler, faster assembly process compared to aligning and bolting multiple endplates, while still providing secure retention under high pressure conditions.
Solution Approach 2:
The retaining elements are pre-formed as integral parts of the end cap structure, eliminating the need for separate bolting operations. The elements are designed to be directly inserted into the axial slots and rotated into position, streamlining the assembly process and reducing both time and cost while maintaining reliable retention.
3Reliability
If end caps are retained using heavy endplates, then the end caps are securely held, but the complexity of the valve structure increases
Solution Approach 1:
The retention function is segmented into discrete retaining elements that are integral to the end cap, rather than requiring separate endplates and multiple bolts. This reduces structural complexity while maintaining secure retention, as the retaining elements are simple geometric features that engage with corresponding slots in the groove.
Solution Approach 2:
The retaining function is merged into the end cap structure itself through the radially outwardly extending retaining elements, eliminating the need for separate endplates. This integration simplifies the overall valve structure while maintaining reliable end cap retention under high pressure conditions.
Data Source
AI summary
A valve assembly includes a valve housing having a bore formed therein. The bore has an axis A and comprises a circumferentially extending groove formed at an end portion. An axially outer wall of the groove includes at least two circumferentially spaced radially inwardly extending retaining elements defining an axial slot therebetween. An end cap is received in the end portion of the bore and closes the end of the bore. The end cap includes a retaining portion that includes at least one radially outwardly extending retaining element which is shaped to be insertable through the axial slot into the groove and rotatable therein to a retaining position in which the radially outwardly extending retaining element aligns with one of the radially inwardly extending retaining elements to prevent axial withdrawal of the end cap from the bore.