Disconnectable Axle Assembly with Planetary Differential

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Solution Overview

Problem

Modern automotive vehicles with all-wheel drive or four-wheel drive drivelines require a compact, robust, and cost-effective disconnect mechanism for the axle assembly that enhances traction and fuel economy, but existing solutions are not optimized for reduced size and mass.

Innovation Solution

The axle assembly incorporates a housing assembly with an input pinion, ring gear, differential assembly, and a clutch system featuring a coupling member with external and internal teeth, a spring bias, and a linear motor for selective engagement, allowing for compact design and efficient power transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a disconnect mechanism is added to enhance traction and fuel economy, then driveline functionality is improved, but device complexity increases

Engineering Contradiction:
Improvedriveline functionalityVSAvoidaxle assembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The disconnect mechanism is merged with the differential assembly by integrating the clutch directly into the differential housing. The clutch assembly includes a clutch drum, clutch plates, and springs that are combined with the differential components, allowing the disconnect function to be performed without adding a separate complex disconnect mechanism. This merging reduces overall device complexity while maintaining enhanced driveline functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The differential housing serves multiple functions: it houses the differential mechanism, contains the disconnect clutch assembly, and provides mounting for bearings and gears. The clutch assembly itself performs both the disconnect function and transmits power when engaged. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity while maintaining adaptability.

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

2Weight of moving object

If the axle assembly is made more compact to reduce size and mass, then vehicle efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveaxle assembly massVSAvoidcomponent alignment precision
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The clutch assembly is nested within the differential housing, with the clutch drum positioned inside the differential assembly. The clutch plates are nested between the clutch drum and the differential case. This nested arrangement allows multiple components to occupy the same spatial envelope, reducing the overall size and mass of the axle assembly while maintaining proper component alignment through the hierarchical nesting structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The planet gears are arranged in a three-dimensional configuration around the sun gear, utilizing radial and axial dimensions to achieve compact packaging. The clutch components are arranged axially within the differential housing, using the axial dimension to stack components efficiently. This multi-dimensional arrangement reduces the overall footprint and mass of the assembly while maintaining manufacturing precision through standardized component interfaces.

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 configuration enables a compact, robust, and cost-effective disconnect mechanism that optimizes traction and fuel economy by allowing selective coupling of output members, reducing size and mass while maintaining efficient power transmission.

Implementation Method 1

a linear motor for selective engagement

Methodology Applied
Scientific EffectLinear motor: Linear Motor

Implementation Method 2

a spring bias

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3408111B1Disconnectable axle assembly having a planetary differential
Publication Date: 2021.09.22 AMERICAN AXLE & MANUFACTURING INC
  • EP3408111B1 patent drawingFigure 1
  • EP3408111B1 patent drawingFigure 2

AI summary

A disconnecting axle assembly with a planetary differential assembly and a coupling that selectively couples a planet carrier of the planetary differential assembly to an axle shaft.