Flapper Servo Valve Nozzle Housing Segmented Cavity Design
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Solution Overview
Problem
The existing nozzle housings for flapper servo valves face issues with nozzle misalignment and material scraping during calibration, leading to contamination and potential malfunction due to the tight interference fit and differing material hardness between the nozzle and housing.
Innovation Solution
The proposed nozzle housing design features a three-part cylindrical structure with a transition portion and chamfered surfaces to guide the nozzle into position, reducing misalignment and friction, and includes anodized surfaces to minimize material scraping, with the nozzle made of a harder material like stainless steel 304.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the nozzle is interference fitted into the nozzle cavity with tight tolerance, then the nozzle is securely held in position, but the nozzle edges can scrape off material from the cavity surface causing contamination
Solution Approach 1:
The nozzle cavity is divided into three distinct cylindrical portions with different diameters. The first portion (larger diameter) receives the nozzle, the second portion (smaller diameter) provides the interference fit to hold the nozzle, and the third portion provides support. This segmentation allows the nozzle to be inserted without scraping while still achieving secure positioning through the interference fit in the second portion.
Solution Approach 2:
The first cylindrical portion with the larger diameter acts as an intermediary that facilitates the insertion of the nozzle into the cavity. It provides a larger clearance that prevents scraping during insertion, while the second cylindrical portion with the smaller diameter provides the actual interference fit for secure holding. The intermediary first portion mediates between the need for easy insertion and secure positioning.
2Strength
If the nozzle material is harder than the housing material, then the nozzle maintains its shape and precision, but material scraping is more acute when the nozzle is moved axially
Solution Approach 1:
The segmented cavity structure with three cylindrical portions of different diameters allows the harder nozzle to be inserted without scraping the softer housing material. The first portion with larger diameter provides clearance that prevents the hard nozzle edges from scraping the soft housing, while the second portion provides the interference fit for secure positioning.
3Ease of operation
If the nozzle is moved axially within the cavity for calibration, then the nozzle position can be adjusted for accurate operation, but the nozzle edges can interfere with the cavity surface causing scraping
Solution Approach 1:
The cavity is segmented into three cylindrical portions that facilitate axial movement of the nozzle during calibration. The first portion with larger diameter allows the nozzle to move axially without scraping, while the second and third portions with smaller diameters provide interference fits that secure the nozzle at calibrated positions. This segmentation enables easy calibration operation without material scraping.
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 design ensures precise alignment and reduces material scraping, maintaining the accuracy and reliability of the flapper servo valve by minimizing contamination and ensuring smooth operation.
Implementation Method 1
The nozzle housing (8) comprises a nozzle cavity (10) having a first open end (10a) and a second open end (10b) and a flapper cavity (8c} for housing a flapper (2). The nozzle cavity (10) comprises a first cylindrical portion (12), a second cylindrical portion (16) and a third cylindrical portion (14) positioned therebetween.
Data Source
Figure 1
Figure 2a~2b
Figure 2c~3a
AI summary
A nozzle housing (8) comprising a nozzle cavity (10) having a first cylindrical portion (12) for receiving a nozzle (6) inserted into the nozzle cavity (10), a second cylindrical portion (16) configured to hold the nozzle (6) in its operating position and a third cylindrical portion (14) positioned between the first and second cylindrical portions (12; 16) for centering the nozzle (6) prior to positioning in the second cylindrical portion (16). The first, second and third cylindrical portions (12, 14, 16) are coaxial, and the diameter (D3) of the third cylindrical portion (14) is smaller than the diameter (D1) of the first cylindrical portion (12) but larger than the diameter (D2) of the second cylindrical portion (16). First and second transition portions (13, 15 connect the first cylindrical portion (12) to the third cylindrical portion (14) and the third cylindrical portion (14) to the second cylindrical portion (16), respectively.