Clutch Collar Axle Shift Mechanism for Compact Differential Packaging

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Solution Overview

Problem

Existing axle assemblies with clutch collars lack an efficient mechanism for shifting the clutch collar between engagement and disengagement positions, leading to complexity and weight in the drivetrain.

Innovation Solution

The axle assembly incorporates a clutch collar shift mechanism that includes a piston, a bearing assembly, and a biasing member, allowing the clutch collar to move between positions using pressurized fluid and a compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a traditional clutch collar shift mechanism is used, then the clutch collar can be shifted between engagement and disengagement positions, but the mechanism becomes complex and heavy

Engineering Contradiction:
Improveshift mechanism complexityVSAvoiddrivetrain weight
Core Design Contradiction:
Device complexityVSWeight of moving object

Solution Approach 1:

The patent combines the clutch collar shift mechanism with the interaxle differential unit by integrating the piston, bearing assembly, and biasing member directly into the differential housing. This merging eliminates the need for separate shift mechanism components, reducing overall complexity and weight while maintaining the ability to shift the clutch collar between engagement and disengagement positions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The differential housing serves multiple functions: it houses the interaxle differential mechanism, contains the clutch collar shift mechanism components (piston, bearing assembly, biasing member), and provides the cavity for pressurized fluid actuation. This multi-functionality reduces the number of separate components needed, thereby simplifying the overall system and reducing weight.

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

2Volume of moving object

If a compact clutch collar shift mechanism is implemented, then packaging efficiency improves, but the mechanism for shifting the clutch collar becomes more complex

Engineering Contradiction:
Improveaxle assembly volumeVSAvoidshift mechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The clutch collar shift mechanism components (piston, bearing assembly, biasing member) are nested within the interaxle differential unit housing. The piston encircles the clutch collar, the bearing assembly is positioned between the piston and clutch collar, and the biasing member is disposed within the differential unit. This nesting arrangement achieves compact packaging while maintaining functional simplicity through integrated design.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If pressurized fluid is used to move the clutch collar, then the shift mechanism becomes simpler, but fluid sealing requirements increase complexity

Engineering Contradiction:
Improveshift mechanism complexityVSAvoidfluid sealing reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces seals as intermediary elements between the pressurized fluid cavity and the external environment. The seals are integrated into the piston and housing structure, creating reliable fluid barriers that maintain pressurized fluid containment while allowing the piston to move axially. This intermediary sealing approach enables simple pressurized fluid actuation while ensuring reliability through properly positioned seal elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution simplifies the shift mechanism, reduces weight, and improves packaging efficiency, leading to a more compact and lightweight axle assembly with enhanced fuel economy.

Implementation Method 1

The bearing assembly facilitates rotation of the clutch collar with respect to the piston

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The clutch collar is moveable along the axis when a pressurized fluid is provided to the cavity

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 3

The biasing member may urge the clutch collar and the piston to move along the axis from the second position toward the first position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4542071A1Axle assembly having a clutch collar
Publication Date: 2025.04.23 ARVINMERITOR TECHNOLOGY LLC
  • EP4542071A1 patent drawingFigure 1
  • EP4542071A1 patent drawingFigure 2
  • EP4542071A1 patent drawingFigure 3

AI summary

An axle assembly having a clutch collar. The axle assembly includes a shaft, a piston, a bearing assembly, and the clutch collar. The piston encircles the clutch collar. The bearing assembly extends from the piston to the clutch collar and facilitates rotation of the clutch collar with respect to the piston.