Hollow-Shaft Pump Coupling for High-Speed Modular Maintenance
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Solution Overview
Problem
Existing pump assemblies face challenges in increasing maximum speed while maintaining a compact design, as known releasable connections introduce dynamic imbalances and require tight manufacturing tolerances, leading to increased costs and complexity.
Innovation Solution
A modular pump assembly with a hollow motor drive shaft and a drive shaft coupling that is freely positionable in axial direction, allowing for easy release without disassembling the pump drive shaft, and featuring a compact design with reduced manufacturing tolerances to minimize dynamic imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a releasable connection is used between motor drive shaft and pump drive shaft, then ease of maintenance is improved, but dynamic imbalance and eccentricity increase at high rotational speeds
Solution Approach 1:
A coupling device is introduced as an intermediary element between the motor drive shaft and pump drive shaft. This coupling device includes a coupling body with an inner cavity that receives the pump drive shaft, and a fastening element that can be inserted through the hollow motor drive shaft to secure the coupling. This intermediary structure enables easy release and reassembly while maintaining precise alignment and minimizing dynamic imbalance through its symmetric design and friction-based connection.
2Reliability
If tight manufacturing tolerances are applied to achieve angular alignment, then rotational balance is improved, but manufacturing cost increases
Solution Approach 1:
The coupling device incorporates self-aligning features through its geometric design. The inner cavity of the coupling body is designed to guide the pump drive shaft into proper alignment, and the fastening element creates a friction-based connection that maintains angular alignment without requiring tight manufacturing tolerances. The symmetric structure of the coupling ensures automatic centering, allowing standard manufacturing tolerances while achieving the required rotational balance.
3Adaptability or versatility
If the drive shaft coupling is made freely positionable in axial direction, then adaptability is improved, but positioning precision may worsen
Solution Approach 1:
The coupling device allows axial movement during assembly and operation. The fastening element can be inserted through the hollow motor drive shaft and secured at different axial positions, enabling adaptation to various pump drive shaft lengths and configurations. Once secured, the friction-based connection maintains precise relative positioning between the motor drive shaft and pump drive shaft, combining adaptability with positioning precision.
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 enables increased operational range and maximum speed while maintaining a compact design, reduces manufacturing costs by relaxing tolerances, and allows for easy maintenance and interchangeability of the motor drive without disassembling the pump.
Implementation Method 1
the drive shaft coupling is arranged at least partly within the hollow motor drive shaft for transferring torque from the motor drive shaft to the pump drive shaft by frictional connection with a radial inner surface of the hollow motor drive shaft and/or a radial outer surface of the pump drive shaft
Data Source
AI summary
A pump assembly includes an electric drive motor with a motor drive shaft and a rotor. The motor drive shaft extends along a rotor axis and the rotor is mechanically coupled to the motor drive shaft. A pump housing encloses an impeller that is mechanically coupled to a pump drive shaft. The pump drive shaft extends along the rotor axis. The motor drive shaft is releasably coupled to the pump drive shaft by a drive shaft coupling for transferring torque from the motor drive shaft to the pump drive shaft. The drive shaft coupling is arranged within the motor drive shaft for transferring torque from the motor drive shaft to the pump drive shaft by frictional connection. The drive shaft coupling is accessible by an elongate tool through the second axial hollow motor drive shaft drive end for selectively tightening and releasing the drive shaft coupling.