Dual-Sided Impeller Wheel for Cooling Stator Winding Heads

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Solution Overview

Problem

Existing electric machines for motor vehicles lack effective cooling of the stator winding heads, which hinders efficiency improvements.

Innovation Solution

A fan wheel design with an annular base body featuring intake openings, air deflection zones, and fan blades on both sides to direct airflow specifically towards stator winding heads, combined with opposing cooling channels within the rotor to enhance cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional fan wheel design is used, then the structure is simple, but the cooling effect on stator winding heads is insufficient

Engineering Contradiction:
Improvecooling effect on stator winding headsVSAvoidfan wheel structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The fan wheel is segmented into multiple functional zones: a first region with fan blades for generating airflow, a second region with deflection surfaces for directing airflow radially outward, and a third region with intake openings for cooling medium passage. This segmentation allows each zone to perform its specific function optimally, improving cooling effectiveness while maintaining manageable structural complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the fan wheel are designed with different structural characteristics tailored to their specific functions. The first region has blades optimized for air generation, the second region has deflection surfaces for radial flow direction, and the third region has openings for cooling medium intake. This local differentiation of structural quality enables effective cooling of stator winding heads without requiring uniform complexity throughout the entire structure.

Inventive Principle:
Principle #3Local quality

2Temperature

If cooling channels are added to improve cooling, then the cooling effect increases, but the device complexity increases

Engineering Contradiction:
Improvecooling effectVSAvoidcooling channel structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The fan wheel structure serves multiple functions simultaneously: it generates airflow through its blades, directs airflow radially outward through deflection surfaces, and provides pathways for cooling medium passage through intake openings. By combining these functions into a single multi-functional component, the design achieves effective cooling without proportionally increasing device complexity.

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

Solution Approach 2:

The fan wheel merges the functions of air generation, flow direction, and cooling medium passage into a single integrated structure. The first, second, and third regions are combined in one component, eliminating the need for separate cooling devices and reducing overall system complexity while maintaining effective cooling performance.

Inventive Principle:
Principle #5Merging (Combining)

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

The design effectively cools the stator winding heads, enhancing the performance and efficiency of the electric machine by targeted airflow and counter-rotating cooling medium flows.

Implementation Method 1

a volume flow of a cooling medium can be guided through the intake opening

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

an air deflection area is formed in the circumferential direction of the base body next to the intake opening

Methodology Applied
Scientific EffectFlow deflection:

Data Source

PatentEP4073389B1Impeller wheel for a rotor, and electric machine
Publication Date: 2026.01.28 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4073389B1 patent drawingFigure 1
  • EP4073389B1 patent drawingFigure 2
  • EP4073389B1 patent drawingFigure 3

AI summary

The invention relates to an impeller wheel (10) for an electric machine (14) of a motor vehicle, with a main body (16) of annular configuration which has at least one intake opening (28) and an air deflection region (30) which is configured next to the intake opening (28) in the circumferential direction of the main body (16), wherein the main body (16) of annular configuration has a first side (18) and a second side (20) which is configured so as to be spaced apart from the first side (18) in the axial direction of the main body (16), a plurality of first impeller wheel blades (36) which are arranged spaced apart from one another in the circumferential direction of the main body (16) are arranged on the first side (18), and a plurality of second impeller wheel blades (50) which are arranged spaced apart from one another in the circumferential direction of the main body (16) are arranged on the second side (20).