Servovalve Nozzle Locking Nut for Accurate Press-Fit Positioning
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Solution Overview
Problem
Existing servovalve nozzle positioning systems face challenges with constant press-fits that lead to manufacturing complexity, high costs, and accuracy issues due to tight tolerances, as well as potential damage during calibration due to axial forces and thermal expansion differences between nozzle and housing materials.
Innovation Solution
A system and method for positioning and locking a nozzle within a servovalve body using a tubular nozzle with a threaded inner surface and a ring-shaped locking member, where the locking member is screwed in to create a press-fit, and an anti-rotation mechanism prevents rotation, allowing for easier calibration and reduced axial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a constant press-fit is used to position the nozzle within the valve body, then the nozzle positioning accuracy is improved, but the manufacturing complexity and cost increase due to tight tolerances
Solution Approach 1:
The nozzle assembly is segmented into two functional parts: the nozzle itself and a separate locking member. The locking member is screwed into the nozzle to create a press-fit between the nozzle outer surface and the valve body inner surface. This segmentation allows the nozzle to be positioned and locked independently, reducing the need for tight tolerances on the nozzle-body interface while maintaining positioning accuracy.
Solution Approach 2:
The locking member is pre-threaded onto the nozzle before assembly, and the threaded connection is established in advance. This preliminary action allows the press-fit to be created between the nozzle and valve body without requiring the nozzle to be precisely fitted during final assembly, thereby reducing manufacturing complexity and cost while maintaining positioning accuracy.
2Manufacturing precision
If a constant press-fit is used to position the nozzle, then the nozzle positioning accuracy is improved, but the risk of damage during calibration increases due to axial forces
Solution Approach 1:
By separating the nozzle positioning function from the nozzle body through the introduction of a locking member, the axial forces during calibration are isolated to the locking mechanism rather than being transmitted to the nozzle-body interface. This protects the precision positioning from damage while maintaining accuracy.
Solution Approach 2:
The locking member acts as an intermediary between the nozzle and the valve body. It absorbs and isolates the axial calibration forces, preventing them from being transmitted to the nozzle positioning interface. This intermediary mechanism protects the precision components from damage during calibration while maintaining positioning accuracy.
3Reliability
If different materials are used for nozzle and housing, then thermal expansion differences cause positioning errors, but using the same material increases manufacturing complexity
Solution Approach 1:
The locking mechanism segments the thermal expansion effects. The locking member can be made from a material that accommodates thermal expansion, while the nozzle and valve body can use different materials optimized for their specific functions. This segmentation allows thermal compensation without requiring all components to be made from the same material, reducing manufacturing complexity while improving thermal cycle resistance.
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
This solution provides a more reliable and easier calibration process with reduced manufacturing complexity and cost, improved accuracy, and increased resistance to thermal cycles by minimizing axial forces and using simpler equipment, while maintaining a sufficient press-fit for nozzle positioning.
Implementation Method 1
The locking member further comprises an outer circumferential surface having a thread that corresponds to the thread of the inner surface of the nozzle. The system further comprises means for providing torque to the locking member, to screw said locking member into and within said nozzle via said threaded surfaces, to thereby create a press-fit between said outer cylindrical surface of the nozzle and an inner surface of said body having said cylindrical bore.
Data Source
AI summary
A system is described for positioning and locking in place a nozzle within a cylindrical bore of a body, and a method for positioning and locking in place a nozzle within a cylindrical bore of a body is also described. The system has a nozzle having a tubular shape extending between a first end and a second end with an outer cylindrical surface and an inner surface, said inner surface comprising a thread. The system also has a locking member provided within said nozzle and comprising an outer circumferential surface having a thread that corresponds to the thread of the inner surface of the nozzle. The system also has means for providing torque to said locking member to screw said locking member into and within said nozzle via said threaded surfaces to thereby create a press-fit between said outer cylindrical surface and an inner surface of said cylindrical bore.