Stator Sleeve Axial Locking for Space-Saving Anti-Rotation

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Solution Overview

Problem

Existing electric machines require complex and space-intensive anti-rotation devices to secure the stator sleeve within the housing, which is exacerbated by stator laminated core deformation during assembly, necessitating additional tolerance compensation.

Innovation Solution

An axial securing element, such as a screw bolt, is extended beyond the stator sleeve and engages with a counter contour on the housing, providing anti-twist protection without additional radial or inner space, with a press fit or screw connection that compensates for tolerances through a groove-shaped recess and hole clearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional anti-rotation devices (pressing, welding, screwing) are used to secure the stator sleeve in the housing, then rotationally secure positioning is achieved, but the installation space requirement becomes excessively large

Engineering Contradiction:
Improverotationally secure positioningVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The locking element utilizes the axial dimension (z-direction) by extending beyond the end edge of the stator sleeve to engage with the housing, rather than requiring additional radial space. This dimensional shift allows anti-rotation functionality without increasing the radial footprint of the stator assembly.

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

Solution Approach 2:

The anti-rotation function is segmented into a dedicated locking element that is axially extended from the stator sleeve, separating the anti-rotation mechanism from the main stator body. This segmentation allows the locking element to engage with the housing in a space-efficient manner while maintaining rotational security.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the stator sleeve is pressed into the housing to achieve anti-rotation, then rotationally secure positioning is achieved, but the stator sleeve deformation requires complex anti-rotation device design to compensate for tolerances

Engineering Contradiction:
Improverotationally secure positioningVSAvoidanti-rotation device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking element's axial height and engagement geometry are designed to accommodate tolerance variations caused by stator sleeve deformation. By adjusting these parameters, the device maintains effective anti-rotation engagement despite dimensional variations in the pressed-fit stator sleeve.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The locking element acts as an intermediary component between the stator sleeve and housing, providing a dedicated engagement interface that compensates for deformation-induced tolerances. This intermediary structure simplifies the overall design by isolating the tolerance compensation function from the main anti-rotation mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If additional radial or inner space is used for anti-rotation devices, then rotationally secure positioning is achieved, but the available installation space in the electric machine housing is reduced

Engineering Contradiction:
Improverotationally secure positioningVSAvoidavailable installation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The solution transitions the anti-rotation mechanism from radial space consumption to axial space utilization. The locking element extends in the axial direction beyond the stator sleeve's end edge, engaging with the housing without encroaching on the radial installation space required by conventional anti-rotation devices.

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

Data Source

PatentEP4485760A1Electric machine with stator sleeve Anti-rotation lock
Publication Date: 2025.01.01 AUDI AG
  • EP4485760A1 patent drawingFigure 1
  • EP4485760A1 patent drawingFigure 2~3
  • EP4485760A1 patent drawingFigure 4~5

AI summary

The invention relates to an electric machine with an assembly consisting of a stator sleeve (17) and a stator lamination stack (15), in which the stator sleeve (17) is inserted into a hollow cylindrical electric machine housing (1) in a rotationally secure manner. According to the invention, the stator sleeve (17) is extended in the axial direction by at least one locking element (27). The locking element (27) is positively engaged with a counter contour (31) on the housing side, thereby providing a rotational locking mechanism for the stator sleeve (17) relative to the electric machine housing (1).