Motor Pump Air-Gap Sleeve Mounting via Rib Shearing
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Solution Overview
Problem
Existing methods for securely mounting plastic containment shells in stator recesses of electric motors face challenges where a secure press fit leads to material stress and a material-friendly fit results in insufficient support, failing to balance security and material integrity.
Innovation Solution
The containment shell is equipped with axially parallel protruding ribs made of plastic, whose height is initially greater than the radial width of the annular space, allowing the ribs to be sheared upon insertion to achieve a precise press fit without material stress, ensuring a secure hold with both form and friction fits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a secure press fit is achieved in the stator, then the containment shell is securely held, but the plastic material of the containment shell is stressed
Solution Approach 1:
The containment shell is segmented with multiple axially parallel protruding ribs that distribute the mounting stresses across multiple localized contact points rather than a continuous circumferential contact, reducing overall material stress while maintaining secure holding
Solution Approach 2:
The ribs are designed with specific dimensional characteristics (height, thickness, spacing) that create localized high-strength connection zones at the rib-stator interfaces while the remaining containment shell material experiences minimal stress, achieving local quality optimization
2Strength
If a material-friendly fit is achieved, then the plastic material is not stressed, but there is insufficient support
Solution Approach 1:
The ribs are pre-formed on the containment shell with heights greater than the radial width of the annular space before insertion, ensuring that upon insertion they automatically engage the stator inner surface at the correct depth to provide sufficient support without requiring additional adjustment or forcing
Solution Approach 2:
The rib structure enables the containment shell to self-center and self-adjust during insertion into the stator recess, with the ribs naturally engaging the stator inner surface to provide both support and secure holding without external assistance or additional components
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 enables a secure and stress-free mounting of the containment shell within the stator recess, maintaining material integrity while providing a stable and backlash-free connection, effectively addressing the balance between secure hold and material stress.
Implementation Method 1
a front sharp edge of the stator recess shears the height of the ribs
Implementation Method 2
a front sharp edge of the stator recess shears the height of the ribs to such an extent that the containment can rests in the stator recess with a press fit
Data Source
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AI summary
The invention relates to a method for coaxially mounting a plastic air-gap hood of a motor pump in the recess of the stator of an electric motor driving a pump, wherein between the outer face of the air gap hood and the inner face of the stator recess there is a coaxial annular space as clearance. The air gap hood is provided with a plurality of axially parallel projecting ribs made of plastic on the outer face thereof, wherein the height of said ribs is greater than the radial width of the annular space. When the air gap hood is pushed coaxially into the stator recess, a leading sharp edge of the stator recess reduces the height of the ribs by cutting to such an extent that the air gap hood engages the stator recess with an interference fit.