Servo Valve Nozzle Assembly for Easier Calibration and Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current servo valve nozzle designs face challenges due to tight interference fits between nozzles and housing, requiring high manufacturing tolerances, making production expensive and calibration difficult, and disrupting fluid flow during calibration.
Innovation Solution
A nozzle assembly with a plug element and filter element, where the plug element is threadedly mounted and includes a bore for a push rod, and an annular wall for sealing engagement, allowing for a sealing fit rather than a tight interference fit, enabling easier calibration and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tight interference fit is used to secure the nozzle in the housing, then the nozzle remains in the correct position at all operating temperatures, but the manufacturing tolerances become very high and production cost increases
Solution Approach 1:
A plug element is introduced as an intermediary component between the nozzle and housing. The plug element receives the interference fit from the housing and transfers it to the nozzle, while also providing a threaded attachment for the push rod. This mediator allows the housing-nozzle connection to be secured without requiring extremely tight tolerances between the housing and nozzle themselves.
Solution Approach 2:
The design changes the connection mechanism from a direct interference fit between nozzle and housing to a threaded connection via the plug element. This parameter change allows for controlled engagement and adjustment, reducing the need for high manufacturing precision while maintaining secure positioning.
2Reliability
If a tight interference fit is used to secure the nozzle in the housing, then the nozzle remains in the correct position at all operating temperatures, but calibration becomes difficult
Solution Approach 1:
The plug element serves as a mediator that provides a threaded attachment point for the push rod used during calibration. This allows the nozzle to be easily adjusted axially during calibration while the interference fit on the plug element itself ensures stable positioning during operation.
Solution Approach 2:
The connection system is segmented into three parts: the housing with interference fit, the plug element with threaded attachment, and the nozzle. This segmentation allows the calibration function (moving the nozzle) to be separated from the securing function (interference fit), enabling easy calibration without compromising operational stability.
3Reliability
If a tight interference fit is used to secure the nozzle in the housing, then the nozzle remains in the correct position at all operating temperatures, but the nozzle housing becomes over-stressed
Solution Approach 1:
The plug element acts as a stress-distributing intermediary between the housing and nozzle. The interference fit is applied to the plug element rather than directly to the nozzle, and the plug element's threaded connection to the nozzle distributes the securing forces more evenly, reducing stress concentration on the housing.
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 solution simplifies calibration by avoiding interference with fluid flow and reduces manufacturing costs by allowing less stringent tolerances, enhancing the ease and accuracy of nozzle assembly and positioning.
Implementation Method 1
The plug element may be threadedly mounted within the second axial end of the nozzle element
Implementation Method 2
The annular wall may define an internal cavity open at one end, the cavity tapering inwardly in a direction towards the nozzle element for receiving a pin
Implementation Method 3
a pin received within the tapering cavity defined by the annular wall of the plug element for forcing the annular wall of the plug element into sealing and gripping engagement with the bore of the nozzle housing
Implementation Method 4
The nozzle may further comprise a filter element mounted across the internal cavity of the nozzle element at a position axially intermediate the one or more openings and the fluid outlet
Data Source
AI summary
A nozzle of or for a servo valve comprises a nozzle element having a fluid outlet at a first axial end and a tubular body extending from the first end to an opposed, second axial end. The nozzle further comprises a plug element mounted in and closing the second axial end of the tubular body, thereby defining an internal cavity within the tubular body. One or more openings are formed through the tubular body to fluidly communicate with the internal cavity. A filter may be mounted across the internal cavity at a position axially intermediate the openings and the fluid outlet.