Jet Pipe Servo Flexure Pivot and Rigid Seal
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Solution Overview
Problem
Existing servomechanisms, particularly jet pipe-type servos, face challenges in maintaining reliability and accuracy in high temperature, high vibration, and contaminated environments due to sensitivity to contamination and induced vibrations, and require complex and costly flexible seals to isolate electromagnetic coils from hydraulic fluid.
Innovation Solution
A jet pipe servo device is designed with a flexure pivot mounting system, where the jet pipe is fixed with respect to one part and movable with respect to another, allowing pivoting to direct output media, and a rigid seal tube isolates the coil without contacting moving components, eliminating the need for a flexible seal and reducing vibration effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible seal tube is used to isolate the coil from the hydraulic fluid, then the coil is isolated from contamination, but the device complexity and manufacturing cost increase due to the need for flexible seals
Solution Approach 1:
The patent extracts the flexible seal from the system by using a rigid seal tube that extends stationary from the coil assembly. This eliminates the need for flexible seals while maintaining coil isolation from hydraulic fluid contamination, directly resolving the contradiction between reliability and device complexity
Solution Approach 2:
The design segments the seal function from the moving components. The rigid seal tube is fixed to the coil assembly and remains stationary, separating the sealing function from the jet pipe movement, thereby eliminating flexible seal requirements while maintaining effective isolation
2Ease of operation
If a flexible seal is used to permit jet pipe movement, then the jet pipe can pivot to direct media, but hysteresis and vibration sensitivity increase
Solution Approach 1:
The patent removes the flexible seal from the jet pipe assembly, eliminating the source of hysteresis and vibration sensitivity. The jet pipe can still pivot freely on its pivot axis without being constrained by flexible seal mechanics, resolving the contradiction between operational ease and reliability
Solution Approach 2:
Instead of making the seal flexible to accommodate movement, the patent inverts the approach by making the seal rigid and stationary, allowing the jet pipe to move freely against the rigid seal structure, thereby eliminating hysteresis while maintaining pivoting capability
3Object-affected harmful factors
If larger nozzle orifices are used in jet pipe configurations, then contamination sensitivity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the parameter of nozzle orifice size to be larger, which reduces sensitivity to contamination. The rigid seal tube design enables this parameter change by providing stable, predictable flow characteristics that maintain manufacturing precision even with larger orifices
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 enhances reliability and accuracy by reducing hysteresis, manufacturing complexity, and cost, while maintaining performance in harsh environments, and eliminates issues like pressure and temperature-induced null shifts.
Implementation Method 1
A flexure pivot can have a first part fixed with respect to the coil and second part linked to the armature and movable therewith with respect to the first part
Implementation Method 2
an electromagnet assembly including a coil and an armature
Data Source
AI summary
A servomechanism has a jet pipe mounted by a flexure pivot driven by an electromagnet to control the position of the jet pipe. A fixed seal tube surrounds the armature and keeps the coil isolated and dry. The flexure pivot has two parts that can move with respect to one another. The jet pipe can be fixed with respect to one part and movable with respect to the other such that when the electromagnet armature moves pivotal motion is imparted to the jet pipe. A multi-port jet receiver receives media from the jet pipe in different orifices dependent upon armature position. That in turn can extend or retract an actuator, such as a piston, depending upon which receiver orifice receives greater pressure. A feedback mechanism can link the actuator to the jet pipe to provide feedback input used to improve the accuracy of the device.