Remote Electric Drive Axle Layout for Easier EV Retrofitting

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Solution Overview

Problem

Existing electric drive units are inefficiently integrated with axle assemblies, leading to space constraints and increased retrofitting costs when converting internal combustion engines to electric propulsion systems.

Innovation Solution

A remotely positioned electric drive unit with a housing assembly that includes a support housing and drop gear set, allowing for independent installation from the axle assembly, and a lubricant pump system for efficient lubrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the electric drive unit is integrated with the axle assembly, then the torque transmission efficiency is improved, but the space constraints and retrofitting costs increase

Engineering Contradiction:
Improvetorque transmission efficiencyVSAvoidintegration complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The electric drive unit is divided into separate modular components: the electric motor module (with motor and transmission) and the drop gear module (with differential and axles). This segmentation allows independent installation and positioning, reducing integration complexity while maintaining functional efficiency through separate torque transmission paths.

Inventive Principle:
Principle #1Segmentation

2Loss of time

If the electric drive unit is remotely positioned from the axle assembly, then the retrofitting time and costs are reduced, but the torque transmission path becomes longer

Engineering Contradiction:
Improveretrofitting timeVSAvoidtorque transmission path length
Core Design Contradiction:
Loss of timeVSLength of moving object

Solution Approach 1:

A drive shaft serves as an intermediary component connecting the electric motor module to the drop gear module. This intermediary element enables remote positioning of the motor module (reducing retrofitting complexity) while efficiently transmitting torque over the extended distance through the drive shaft, which can be routed through the vehicle frame or chassis.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If the housing assembly is designed to receive all components, then the structural integrity is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvestructural integrityVSAvoidhousing assembly complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The housing assembly merges multiple functions into a single structural component: it houses the electric motor, transmits torque through the drive shaft, supports the drop gear module, and provides mounting points for the entire assembly. This consolidation maintains structural integrity while simplifying manufacturing compared to multiple separate housing components.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4282679B1Electric drive unit and drive axle system
Publication Date: 2026.04.01 ARVINMERITOR TECHNOLOGY LLC
  • EP4282679B1 patent drawingFigure 1
  • EP4282679B1 patent drawingFigure 2
  • EP4282679B1 patent drawingFigure 3

AI summary

An electric drive unit (22) and a drive axle system (12) having an electric drive unit (22). The drive axle system also includes a drive shaft (40) and an axle assembly (20) that that is remotely positioned from the electric drive unit. The drive shaft operatively connects the electric drive unit to the axle assembly.