Axle Assembly Layout With Nested Motor and External Gear Reduction

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Solution Overview

Problem

Existing axle assemblies with electric motor modules face challenges in optimizing package space, balancing, and efficient cooling, particularly when integrating gear reduction modules and differential assemblies.

Innovation Solution

The axle assembly design incorporates an electric motor module positioned inside the differential carrier, with a gear reduction module externally mounted, enhancing compactness and balance, and includes a cooling system with a water jacket to manage heat effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the electric motor module is positioned inside the differential carrier, then the axial length is reduced and compactness is improved, but the manufacturing complexity and assembly difficulty increase

Engineering Contradiction:
Improveaxial lengthVSAvoidassembly complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The electric motor module is nested inside the differential carrier, with the motor positioned within the internal cavity of the carrier structure. This nesting arrangement allows the motor to occupy space that would otherwise be unused, reducing the overall axial length of the axle assembly while maintaining a compact configuration.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The axle assembly is divided into modular components including the differential carrier, electric motor module, and gear reduction module that can be manufactured separately and then assembled. This segmentation allows for specialized manufacturing of each component while enabling flexible assembly configurations to achieve the desired compact layout.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the gear reduction module is externally mounted, then the balance and compactness are improved, but the device complexity increases

Engineering Contradiction:
ImprovebalanceVSAvoiddevice complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The gear reduction module is mounted on the external surface of the differential carrier rather than being integrated within the internal cavity. This external mounting on a different dimensional plane (outer surface vs. inner volume) allows the motor to remain centrally positioned for balance while the gear module occupies external space, achieving both balance and compactness.

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

3Temperature

If the cooling system with water jacket is integrated, then the cooling efficiency is enhanced, but the manufacturing complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The water jacket cooling system is merged with the differential carrier structure, where the carrier serves dual functions as both a structural housing and a thermal management component. The water jacket is integrated into the carrier's wall structure, allowing coolant flow paths to be formed within the existing structural geometry, thereby enhancing cooling efficiency while utilizing the structural form already required for mechanical support.

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

This configuration reduces axial length, improves balance, and enhances cooling efficiency, allowing for a more compact and efficient axle assembly design.

Implementation Method 1

includes a cooling system with a water jacket to manage heat effectively

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3791089B1Method of making a first axle assembly and a second axle assembly
Publication Date: 2026.01.07 ARVINMERITOR TECHNOLOGY LLC
  • EP3791089B1 patent drawingFigure 1
  • EP3791089B1 patent drawingFigure 2
  • EP3791089B1 patent drawingFigure 3

AI summary

An axle assembly and a method of manufacture. The axle assembly may include a differential carrier and a bearing support wall. The differential carrier may be made of a first material. The bearing support wall may be mounted to the differential carrier and may be made of a second material. The second material may have a greater stiffness than the first material.