Borehole Pump Shaft Sleeve Bayonet Lock for Reliable Fixing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing centrifugal pumps, particularly borehole pumps, face challenges in reliably fixing the shaft sleeve to the pump shaft in both rotational and axial directions, with existing solutions like feather key connections and screw clamping being inefficient and requiring significant processing work.

Innovation Solution

The implementation of a bayonet lock mechanism between the shaft sleeve and the pressure ring provides a simple, robust, and self-locking connection, allowing for cost-effective manufacturing and easy assembly/disassembly, while enabling high hydraulic efficiency by minimizing material usage and allowing for the smallest possible impeller inlet inner diameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a keyway connection is used to fix the shaft sleeve for rotational engagement, then rotational stability is improved, but manufacturing complexity and processing work increase

Engineering Contradiction:
Improverotational stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the keyway connection from the shaft sleeve fixation system. Instead of using a keyway to prevent rotation, the patent uses a friction-fit connection between the impeller and shaft sleeve combined with a set screw that can be tightened to secure the connection if needed. This removes the complex machining requirements of keyways while maintaining rotational stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The shaft sleeve is designed with an outer diameter that provides sufficient friction fit to the pump shaft without requiring additional fixation elements. The friction fit itself serves the function of preventing rotation, eliminating the need for keyway machining on both the shaft and sleeve.

Inventive Principle:
Principle #25Self-service

2Reliability

If a screw connection is used to fix the shaft sleeve for axial engagement, then axial stability is improved, but device complexity increases

Engineering Contradiction:
Improveaxial stabilityVSAvoidconnection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the axial fixation function into the friction-fit connection between the impeller and shaft sleeve. The same friction fit that prevents rotation also prevents axial movement, eliminating the need for a separate screw connection for axial engagement. The set screw serves both axial and rotational securing functions when tightened.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The friction-fit connection performs multiple functions simultaneously: it prevents rotation, prevents axial movement, and provides easy assembly and disassembly. This multi-functional connection eliminates the need for separate keyway and screw connections, reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If conventional keyway and screw connections are used, then connection reliability is improved, but assembly and disassembly time increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention segments the fixation system into a simple friction-fit connection that can be assembled and disassembled quickly, with an optional set screw for additional security. This segmented approach allows for rapid assembly by simply sliding the shaft sleeve onto the shaft, and equally rapid disassembly, while maintaining connection reliability through the friction fit and optional screw securing.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4421325A1Centrifugal pump, especially a well pump
Publication Date: 2024.08.28 WILO SE
  • EP4421325A1 patent drawingFigure 1
  • EP4421325A1 patent drawingFigure 2
  • EP4421325A1 patent drawingFigure 3

AI summary

The invention relates to a centrifugal pump, in particular a borehole pump, comprising a pump shaft (1), an impeller (2), a shaft sleeve (3) and a pressure ring (4), wherein the impeller (2), the shaft sleeve (3) and the pressure ring (4) are mounted on the impeller (2), the pressure ring (4) is attached to the impeller (2), and the shaft sleeve (3) and the pressure ring (4) are designed with a corresponding bayonet fitting (6).