Electric Axle Assembly Layout for Motor Cooling and Serviceability

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Solution Overview

Problem

Existing axle assemblies with electric motors face challenges in heat conduction and cooling efficiency, leading to reduced performance and maintenance complexity due to integrated components.

Innovation Solution

The axle assembly design includes a mounting plate that separates the electric motor module from the support structure, allowing for improved cooling through a coolant jacket and air gaps, and positions the transmission module on the opposite side to reduce heat conduction, with a skid plate for protection and a simplified assembly process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the electric motor module is integrated with the support structure, then the assembly is more compact, but heat conduction increases and cooling efficiency decreases

Engineering Contradiction:
Improveaxle assembly compactnessVSAvoidheat conduction
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The electric motor module is segmented from the support structure by the mounting plate, creating a distinct separation that allows independent thermal management. The mounting plate acts as a thermal barrier while maintaining structural integrity, enabling the motor to be positioned optimally for cooling without compromising overall assembly compactness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mounting plate serves as an intermediary element between the electric motor module and the support structure. It provides both mechanical mounting functionality and thermal isolation, preventing direct heat conduction paths while maintaining the structural connection required for load bearing and positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If integrated components are used, then device complexity is reduced, but maintenance complexity increases

Engineering Contradiction:
Improvecomponent integrationVSAvoidmaintenance complexity
Core Design Contradiction:
Device complexityVSEase of repair

Solution Approach 1:

The electric motor module is designed as a segmented, modular unit that can be independently removed from the axle assembly. The mounting plate provides standardized mounting interfaces that facilitate quick detachment and reattachment, enabling maintenance personnel to service the motor without disassembling the entire axle assembly.

Inventive Principle:
Principle #1Segmentation

3Volume of moving object

If the wheel axis is positioned below the rotor axis, then the axle assembly is more compact, but the aisle width in vehicles is reduced

Engineering Contradiction:
Improveaxle assembly compactnessVSAvoidaisle width
Core Design Contradiction:
Volume of moving objectVSLength of moving object

Solution Approach 1:

The mounting plate enables the electric motor module to be positioned in a different spatial arrangement relative to the wheel end assembly. By extending the motor from the first side of the mounting plate while the transmission extends from the second side, the design accommodates the wheel axis positioned above the rotor axis, thereby increasing aisle width without significantly compromising axial compactness.

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

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 design enhances cooling efficiency, reduces heat conduction, simplifies maintenance, and increases the aisle width in vehicles by positioning the wheel axis above the rotor axis, improving performance and ease of assembly.

Implementation Method 1

The coolant jacket may encircle the stator. The coolant jacket may further comprise a set of channels.

Methodology Applied
Scientific EffectHeat transfer: Convection

Implementation Method 2

The bearing assembly may rotatably support the rotor shaft.

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The cover may receive a seal. The seal may extend between the cover and the rotor shaft.

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP4574498A1Axle assembly having an electric motor
Publication Date: 2025.06.25 ARVINMERITOR TECHNOLOGY LLC
  • EP4574498A1 patent drawingFigure 1
  • EP4574498A1 patent drawingFigure 2
  • EP4574498A1 patent drawingFigure 3

AI summary

An axle assembly comprising a support structure, a mounting plate, an electric motor module, a transmission module, and a wheel end assembly. The electric motor module extends from a first side of the mounting plate. The transmission module extends from the second side of the mounting plate. The wheel end assembly extends from the transmission module.