Canned Motor Pump Rotor Can Press-Fit Assembly

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing electrical pump devices with a rotor can separating the stator face challenges in securely and simply connecting additional elements to the rotor can, particularly when using materials like metal that are difficult to solder or weld.

Innovation Solution

The electrical pump device employs a positive and/or press fit connection method to attach elements, such as bearing carriers or shafts, to the rotor can's bottom wall, allowing for secure attachment without the need for welding or soldering, and utilizing preformed bulges in the rotor can for deformation to achieve a press fit, enabling easy centering and positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If welding or soldering is used to connect elements to the rotor can, then a secure connection is achieved, but the assembly process becomes more complex and time-consuming

Engineering Contradiction:

Improveconnection securityVSAvoidassembly process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces welding or soldering (thermal joining methods) with a mechanical press fit connection system. The connection element features a press fit interface that mechanically engages with the rotor can wall, eliminating the need for thermal processes and reducing assembly complexity while maintaining connection security.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a connection element as an intermediary component between the element to be attached and the rotor can. This connection element provides a standardized press fit interface that simplifies the joining process and acts as a mediator that facilitates secure attachment without direct welding or soldering between the component and rotor can.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If welding or soldering is used to connect elements to the rotor can, then a secure connection is achieved, but the assembly time increases

Engineering Contradiction:

Improveconnection securityVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The connection element is pre-formed with the press fit interface geometry during manufacturing. The bulge deformation features are created in advance, allowing the element to be quickly pressed into place during assembly without requiring time-consuming welding or soldering operations, thus reducing assembly time while maintaining connection security.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If additional elements are connected to the rotor can, then functionality is enhanced, but the distance between rotor and stator increases

Engineering Contradiction:

Improvefunctional adaptabilityVSAvoidrotor-stator distance

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The rotor can wall is designed as a thin-walled structure that can accommodate the press fit connection of additional elements without significantly increasing the overall thickness or distance between rotor and stator. The thin film approach allows functional adaptability while minimizing the impact on the critical rotor-stator gap distance.

Inventive Principle:

Principle #30Flexible shells and thin films

4Ease of manufacture

If a press fit connection is used to attach elements to the rotor can, then assembly is simplified and positioning is improved, but the connection strength may be reduced compared to welding

Engineering Contradiction:

Improveassembly simplicityVSAvoidconnection strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The press fit connection utilizes curved or spherical geometry in the connection interface, which distributes mechanical stresses more evenly compared to flat rigid connections. The curved surface of the press fit interface in the rotor can wall helps maintain connection strength while allowing for simplified assembly and improved positioning of additional elements.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 method simplifies the assembly process, ensures a secure connection of diverse materials, and allows for efficient energy transfer while minimizing the distance between the rotor and stator, enhancing the pump's efficiency and reliability.

Implementation Method 1

utilizing preformed bulges in the rotor can for deformation to achieve a press fit

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentEP3757395B1Electrical pump device with canned motor

Publication Date: 2023.06.07 GRUNDFOS HLDG

Figure 1
Figure 2
Figure 3

AI summary

The invention refers to an electrical pump device with a stator (14), a rotor (20) as well as with at least one impeller (22) which is connected to the rotor (20), wherein the stator (14) and the rotor (20) are separated by a rotor can (16), wherein at least one element (30) connected to a bottom wall (50) of the rotor can (16) on an axial end opposite to the at least one impeller (22), wherein the at least one element (30) is connected to the bottom wall (50) of the rotor can (16) by a positive and/or press fit, as well as a method for connecting at least one element (30) to a bottom wall (50) of a rotor can (16) of a pump.