Multi-ribbed Keyless Coupling for Sealless Pump Torque Transmission
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Solution Overview
Problem
Existing magnetic-drive pumps face challenges with keyed and force fit connections that require tight tolerances, increasing manufacturing costs and inhibiting interchangeability, while also complicating maintenance and compatibility with corrosive materials.
Innovation Solution
A magnetically-driven centrifugal pump design featuring a bushing assembly with an inner bearing and outer sleeve, utilizing anti-rotation grips to prevent relative rotation between the bushing assembly and inner drive, allowing for keyless coupling and reduced manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If keyed connections are used to connect the bushing and inner drive, then torque transmission is reliable, but manufacturing precision requirements increase and interchangeability is inhibited
Solution Approach 1:
The coupling connection is segmented into modular components: the bushing with keyway, the inner drive with key, and the key itself. This segmentation allows each component to be manufactured independently with standard tolerances, eliminating the need for high-precision matching while ensuring reliable torque transmission through the key-keyway interface.
Solution Approach 2:
The key acts as an intermediary element between the bushing and inner drive. It mediates the torque transmission function while allowing both the bushing and inner drive to be manufactured with relaxed tolerances. The key compensates for any dimensional variations, ensuring reliable connection without requiring tight manufacturing precision.
2Reliability
If force fit connections are used to connect the bushing and inner drive, then torque transmission is reliable, but device complexity increases and maintenance difficulty increases
Solution Approach 1:
The connection is segmented into removable modular components (bushing, inner drive, key) that can be easily assembled and disassembled. This eliminates the complexity of force fit connections while maintaining reliable torque transmission through the keyed interface, and enables simple maintenance by allowing quick removal and replacement of components.
3Reliability
If tight tolerances are used for keyed connections, then slippage is reduced, but manufacturing costs increase
Solution Approach 1:
The key and keyway are designed with self-aligning features and standard tolerances that automatically ensure proper fit without requiring tight manufacturing tolerances. The geometry of the key-keyway interface self-corrects for minor dimensional variations, preventing slippage while allowing cost-effective manufacturing with relaxed tolerances.
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 simplifies manufacturing, enhances interchangeability, and facilitates easier maintenance by eliminating the need for precise alignment and tight tolerances, while maintaining compatibility with corrosive fluids and ensuring reliable torque transmission.
Implementation Method 1
The inner drive is concentrically disposed within the outer drive such that the inner drive is magnetically coupled to the outer drive through the sealed shell of the wet portion
Implementation Method 2
the plurality of anti-rotation grips along the outer shell deforms the outer shell to prevent relative rotation between the bushing assembly and the inner drive
Data Source
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AI summary
A keyless coupling assembly for connecting concentric shafting components in a sealless pump comprises a first shafting member (50), a second shafting member (48) and a plurality of torque strips (80). The first shafting member comprises an annular body (74) and an inner surface (88) disposed within the annular body. The second shafting member comprises a cylindrical body (64) and an outer surface (90). The cylindrical body (64) is disposed within the inner surface (88) of the first shafting member. The outer surface encircles the cylindrical body and faces the inner surface. The plurality of torque strips is positioned between the outer surface and the inner surface to form anti-rotation grooves in the mating surface to prevent relative rotation between the first and second shafting members.