Dielectric Ball Valve Insert for Insulated Torque Transfer
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Solution Overview
Problem
Actuated ball valves in aircraft and water systems face issues due to conductive paths between metal parts, leading to potential electric shocks and motor faults, necessitating a dielectric barrier and a fall-back drive mechanism.
Innovation Solution
A dielectric insulating insert with a non-circular cross-section engagement portion, made from a substrate with a plasma electrolytic oxidation aluminium layer and an elastic adhesive layer, is positioned between the drive shaft and ball shaft to provide electrical insulation and torque transfer, complemented by a manual handle for backup operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric barrier is introduced between the drive shaft and ball shaft, then electrical insulation is improved, but device complexity increases
Solution Approach 1:
The dielectric insert combines multiple functions into a single component: it provides electrical insulation between the drive shaft and ball shaft, while simultaneously serving as a torque transfer element through its non-circular cross-section engagement portions. This merging eliminates the need for separate insulation and torque transmission components, thereby improving electrical insulation without proportionally increasing device complexity.
Solution Approach 2:
The dielectric insert is designed as a multi-functional component that performs both electrical insulation and mechanical torque transfer. The non-circular cross-section engagement portions enable torque transmission while the dielectric material provides electrical isolation. This universality allows a single component to address multiple requirements, improving reliability without excessive complexity increase.
2Power
If a non-circular cross-section engagement portion is used, then torque transfer is improved, but manufacturing precision requirements increase
Solution Approach 1:
The engagement portions feature a non-circular cross-section with an asymmetric profile including a flat face and rounded lobes. This asymmetric geometry provides superior torque transfer compared to circular sections by preventing relative rotation and ensuring positive engagement. The specific asymmetric shape is designed to balance torque transmission effectiveness with manufacturability, allowing standard machining processes to achieve the required precision.
3Reliability
If a manual handle is added for backup operation, then reliability is improved, but device complexity increases
Solution Approach 1:
The manual handle is pre-configured on the ball shaft to enable immediate manual operation in the event of motor failure. This preliminary preparation ensures that backup operation is readily available without requiring additional complex mechanisms or activation steps. The handle can be directly engaged with the ball shaft through the dielectric insert, providing a simple fail-safe mechanism that improves reliability with minimal complexity addition.
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 effectively prevents electric shocks and ensures continuous operation by maintaining torque transfer while allowing manual operation in case of motor failure, with the dielectric insert providing reliable electrical insulation and minimizing backlash.
Implementation Method 1
The dielectric material may comprise a plasma electrolytic oxidation, PEO, aluminium layer on the substrate
Implementation Method 2
The insert may include a substrate e.g. of aluminium and an outer adhesive layer which may be formed of an elastic adhesive
Data Source
AI summary
A dielectric insulating insert arranged to be positioned between a drive shaft and a ball shaft of a motorised ball valve assembly. The insert includes a body of dielectric material to form an insulating layer and having opposing sides from each of which extends an engagement portion having a non-circular cross-section and configured to engage, respectively, with the drive shaft and the ball shaft in torque transfer engagement.