Double-Walled E-Axle Housing for Cooling and Modular Assembly

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Solution Overview

Problem

E-axle module housings in electric vehicles face challenges due to complex and heavy cast components, which are costly to produce and assemble, and modular gearbox housings have numerous components leading to assembly errors and high costs.

Innovation Solution

A double-walled extruded housing system for the e-axle module with a channel system for cooling and adaptable geometry for various installation conditions, featuring ribs and grooves for flexible mounting and reduced component count, along with an integrated bearing carrier for separating wet and dry components, enabling direct and indirect cooling of power electronics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cast components are used for e-axle module housings, then good thermal conductivity and adaptability to operating conditions are achieved, but manufacturing complexity and weight increase

Engineering Contradiction:
Improvethermal conductivityVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The housing is divided into a modular assembly consisting of a housing body, bearing plates, and integrated cooling elements. This segmentation allows each component to be manufactured separately using simpler processes and then assembled, reducing overall manufacturing complexity while maintaining the thermal conductivity benefits through dedicated cooling channels in the housing body.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If modular gearbox housings are used, then ease of assembly is improved, but the number of components and interfaces increases leading to assembly errors and higher costs

Engineering Contradiction:
Improveease of assemblyVSAvoidnumber of components
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The housing body integrates multiple functions that were previously separate components: the cooling channels are built into the housing structure itself, bearing plates are directly mounted to the housing, and mounting interfaces are incorporated into the housing geometry. This merging reduces the total component count and eliminates numerous interfaces while maintaining modular assembly advantages.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If cast components are used for housings, then individual adaptation to operating conditions is possible, but large-scale production becomes more difficult

Engineering Contradiction:
Improveadaptability to operating conditionsVSAvoidlarge-scale production efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The housing design incorporates universal mounting interfaces and standardized bearing plate connections that can accommodate various operating conditions and configurations. The integrated cooling channels are designed with adjustable flow paths that can be configured for different thermal requirements, allowing a single housing design to serve multiple applications while maintaining high production efficiency through standardization.

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

4Adaptability or versatility

If the housing geometry is made flexible for various installation conditions, then adaptability increases, but manufacturing complexity may increase

Engineering Contradiction:
Improveflexibility for installation conditionsVSAvoidhousing geometry complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The housing incorporates adjustable and reconfigurable elements such as movable mounting brackets, adjustable cooling channel configurations, and flexible connection interfaces. These dynamic features allow the housing geometry to be adapted to different installation conditions without requiring completely different housing designs, maintaining manufacturing simplicity while achieving high flexibility.

Inventive Principle:
Principle #15Dynamics

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 solution provides a cost-effective, lightweight, and flexible housing system with reduced assembly errors, effective heat management, and adaptable installation options, suitable for large-scale production and individual customer configurations.

Implementation Method 1

a channel system for cooling extending beneath a cooling surface of an assembly space for a power electronics system

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

channel system for cooling

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4155111B1System housing of an e-axle module
Publication Date: 2024.06.05 ROBERT BOSCH GMBH
  • EP4155111B1 patent drawingFigure 1
  • EP4155111B1 patent drawingFigure 2
  • EP4155111B1 patent drawingFigure 3

AI summary

The invention relates to a system housing (12) of an e-axle module (10) with a stator winding (50) and a rotor (76) of an electric machine, which is supported in at least a first end shield (54) and a second end shield (56). The system housing (12) is designed as a double-walled extruded housing (14) and includes a cooling system (16). This extends below a cooling surface of a mounting space (18) for accommodating power electronics (70). Furthermore, the invention relates to the use of the system housing (12) of an e-axle module for driving an electric vehicle.