Centrifugal Pump Shaft Guide Section Design
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Solution Overview
Problem
Pump shafts in centrifugal pumps often experience imbalance during rotation, leading to noise and reduced service life due to manufacturing inaccuracies and assembly irregularities, which affect the alignment of the motor shaft and pump shaft axes.
Innovation Solution
A pump shaft design featuring a connecting section with partial circumferential slots and a guide section that allows for radial elastic deformation, ensuring a non-positive connection with the motor shaft, and a second guide section that maintains orientation regardless of assembly asymmetry, combined with a clamping section and guide section that together extend over less than half the axial length of the connecting section, reducing imbalance and improving guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the connecting means are arranged near the free end of the elastically deformable region to improve deformation and separation of functions, then the deformation is significantly facilitated and functional separation is improved, but assembly inaccuracies and irregularities lead to deflection of the motor shaft and imbalance during rotation
Solution Approach 1:
A guide section is introduced as an intermediary element between the clamping section and the non-deformable area. This guide section ensures precise alignment and centered positioning of the motor shaft within the pump shaft, preventing deflection and imbalance caused by assembly inaccuracies while maintaining the functional benefits of the clamping design
2Reliability
If the axial length of the deformable area is made three to five times the axial length of the non-deformable area to achieve reliable clamping, then the clamping reliability is improved, but the device complexity and material consumption increase
Solution Approach 1:
The pump shaft is segmented into distinct functional sections: a non-deformable area, a clamping section with specific axial length, and a guide section. This segmentation allows each section to perform its specific function optimally while reducing the overall axial length requirement compared to making the entire deformable area three to five times longer
Solution Approach 2:
Instead of increasing axial length to improve clamping reliability, the invention introduces a radial dimension through the guide section that provides alignment and stability. This dimensional approach allows reliable clamping with reduced axial length by utilizing radial guidance constraints
3Manufacturing precision
If the connecting section and clamping section extend over a large axial length to ensure proper guidance and clamping, then the guidance accuracy is improved, but the service life is reduced due to increased imbalance and wear
Solution Approach 1:
The invention optimizes the axial length parameter of the clamping section and guide section combination, setting it to extend over less than half the axial length of the connecting section. This parameter optimization achieves sufficient guidance accuracy while minimizing imbalance and wear, thereby extending service life
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 significantly reduces the maximum possible imbalance, enhances clamping and guiding efficiency, and extends the service life of the pump by ensuring precise alignment and symmetrical force introduction, thus minimizing wear and noise.
Implementation Method 1
a clamping section (124) arranged between the guide section and the non-deformable area and radially elastically deformable, wherein the clamping means extend into the clamping section and for producing a non-positive connection with the motor shaft by a clamping means in the circumferential direction
Data Source
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AI summary
The invention relates to a pump shaft (100), which comprises a first portion (102) that can be connected to an impeller (40) of a centrifugal pump, a second portion (104) configured to co-operate with a seal and suitable in particular for receiving an annular seal (22) of a mechanical seal, and a connecting portion (106), wherein the connecting portion (106) comprises a cylindrical cavity (118) having an end face (116) and in which a motor shaft (32) can be received, and the connecting portion (106) has at least two slots (112; 112'; 112") extending predominantly in an axial direction and at least two partially circumferential slots (110) extending predominantly in the circumferential direction, and the connecting portion (106) is sub-divided by the slots (110) extending in the circumferential direction into a guide portion (120) and, to create a force-locked connection with the motor shaft (32), into a clamping portion (124) elastically deformable in the circumferential direction and radial direction by a clamping means (140). In order to improve the pump shaft in such a way that a rotation free of imbalance can be reliably achieved, the connecting portion (106) according to the invention comprises a second guide portion (122) arranged on the side of the clamping portion (124) facing in an axial direction away from the guide portion (120), and at least two partially circumferential slots (114) extending predominantly in the circumferential direction are provided between the second guide portion (122) and the clamping portion (124).