Stator Jacket Plate Weld Seam Thermal Stress Centering

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electrical machine stators are complex in construction and have poor heat dissipation due to the placement of jacket plates and weld seams, which complicates cooling and can lead to inefficiencies in thermal management.

Innovation Solution

An intermediate element is placed in the area of the weld seam between the jacket plate and the stator core, allowing the weld seam to be pressed against the intermediate element, maximizing the contact area between the jacket plate and the stator core, and facilitating a positive fit to enhance torque transmission and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the jacket plate is used to center the laminated stator core with press rings and welding, then the centering function is achieved, but the construction becomes complex

Engineering Contradiction:
Improvecentering of stator coreVSAvoidconstruction complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent removes the press rings and their centering grooves from the structure, extracting the complicating elements while retaining the essential centering function through the simplified jacket plate configuration

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The jacket plate is designed to perform multiple functions: it centers the stator core, provides structural support, and enables cooling, eliminating the need for separate press rings and reducing overall construction complexity

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

2Reliability

If a casing is arranged between the casing plate and laminated core with a recess for the weld seam, then the weld seam is positioned away from the casing, but heat dissipation becomes complicated

Engineering Contradiction:
Improveweld seam positioningVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent eliminates the intermediate casing and its recess structure, removing the thermal barrier that impeded heat dissipation while maintaining reliable weld seam positioning through direct contact between the jacket plate and stator core

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The design transitions from a multi-layer radial structure (casing plate-casing-jacket plate-stator core) to a more direct configuration, improving thermal conduction pathways from the stator core through the jacket plate to the cooling medium

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the abutting edges of the jacket plate are welded together, then a liquid-tight seal is formed, but the contact area between jacket plate and stator core is reduced

Engineering Contradiction:
Improveliquid-tight sealVSAvoidcontact area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The intermediate element acts as a mediator that enables the weld seam to be positioned optimally for creating a liquid-tight seal while simultaneously maintaining maximum contact area between the jacket plate and stator core, resolving the spatial conflict between sealing and thermal contact requirements

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration simplifies the construction of the electrical machine, improves heat dissipation by maximizing the contact surface area, and allows for efficient cooling while maintaining a liquid-tight seal, thereby enhancing the overall performance of the machine.

Implementation Method 1

the weld seam exerts a tensile stress on the shell sheet due to its thermal shrinkage

Methodology Applied
Scientific EffectThermal shrinkage: Thermal Contraction

Data Source

PatentEP2870679B1Stator comprising a stator laminate stack surrounded by a jacket plate
Publication Date: 2016.09.28 SIEMENS AG
  • EP2870679B1 patent drawingFigure 1~2
  • EP2870679B1 patent drawingFigure 3~4
  • EP2870679B1 patent drawingFigure 5~6

AI summary

A stator (1) of an electric machine has a stator laminate stack (6), which extends, when viewed in the direction of an axis of symmetry (5) of the stator laminate stack (6), from a first to a second axial end side (8, 9) of the stator laminate stack (6). The stator laminate stack (6) is surrounded on its outer side (10) by a jacket plate (11), which extends, when viewed around the axis of symmetry (5), from a first to a second abutment edge (12, 13) of the jacket plate (11). The abutment edges (12, 13) extend, when viewed in the direction of the axis of symmetry (5), at least from the first to the second axial end side (8, 9). They are welded to one another, when viewed in the direction of the axis of symmetry (5), by means of a continuous weld seam (14) over the entire length (1) of said abutment edges. The weld seam (14), owing to its thermal shrinkage, exerts a tensile stress on the jacket plate (11). When viewed around the axis of symmetry (5), an intermediate element (15) is arranged in the region of the weld seam (14) and only there between the jacket plate (11) and the stator laminate stack (6). In the remaining region, the jacket plate (11) rests directly on the stator laminate stack (6). Owing to the tensile stress, in the region of the intermediate element (15) the weld seam (14) is pressed in the direction towards the axis of symmetry (5) against the intermediate element (15) and, in the remaining region, the jacket plate (11) is pressed in the direction towards the axis of symmetry (5) against the stator laminate stack (6).