Magnetic Coil Locking Differential Actuation

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Solution Overview

Problem

Conventional electronically triggered locking differentials are complex and costly, and their integration with existing mechanical locking differentials is complicated, posing compatibility issues with anti-lock braking and electronic stability control systems.

Innovation Solution

An electronically triggered vehicle differential design featuring a magnetic coil, flux conductor, and spur gear mechanism that slows the rotation of the cam member to engage the clutch pack, allowing for electronic actuation of the locking mechanism, which is compatible with existing mechanical systems and cost-effective.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If conventional electronically triggered locking differentials are used, then electronic actuation capability is achieved, but device complexity and cost increase significantly

Engineering Contradiction:
Improveelectronic actuation capabilityVSAvoidnumber of parts
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent replaces complex electromagnetic actuators with a simplified magnetic coil system that interacts with existing differential components. The magnetic coil generates a magnetic field that directly influences the cam member's movement, substituting elaborate mechanical or electromagnetic actuation mechanisms with a more straightforward magnetic field-based system that integrates with the differential's inherent geometry.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic coil serves multiple functions: it acts as both the actuating mechanism for electronic triggering and integrates with the existing differential case structure. The flux conductor and bearing race support system further multi-function by providing both magnetic flux path and structural support, reducing the need for separate components.

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

2Extent of automation

If piston-cylinder actuators or electromagnetic systems are used, then electronic triggering is achieved, but the total number of parts increases

Engineering Contradiction:
Improveelectronic triggeringVSAvoidtotal number of parts
Core Design Contradiction:
Extent of automationVSQuantity of substance

Solution Approach 1:

The patent merges the actuating mechanism with existing differential components. The magnetic coil is positioned within the differential case, utilizing the case structure itself as part of the magnetic circuit. The bearing race support and flux conductor are integrated into the existing geometry, combining multiple functions into unified components rather than adding separate discrete parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The flux conductor acts as an intermediary element that guides and concentrates the magnetic field from the coil to the cam member. This intermediary allows the magnetic field to effectively actuate the cam member without requiring direct mechanical contact or complex electromagnetic assemblies, simplifying the overall part structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If mechanical locking differentials are used, then simplicity is maintained, but compatibility with anti-lock braking and electronic stability control systems is reduced

Engineering Contradiction:
Improvesimplicity of designVSAvoidcompatibility with control systems
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the purely mechanical actuation system with an electronically controllable magnetic coil system. This substitution maintains the mechanical simplicity of the locking mechanism while adding electronic triggering capability, enabling compatibility with anti-lock braking and electronic stability control systems that require electrical actuation signals.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system transitions from a static mechanical locking mechanism to a dynamic system where the magnetic coil can be selectively energized and de-energized based on electronic control signals. This dynamic capability allows the differential to respond to inputs from electronic control systems while maintaining the proven reliability of mechanical locking when activated.

Inventive Principle:
Principle #15Dynamics

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

The solution provides a simple, cost-effective means to convert mechanical locking differentials to electronically triggered systems, ensuring compatibility with existing systems and reducing complexity, thereby enhancing operational efficiency and compatibility with advanced vehicle control systems.

Implementation Method 1

a magnetic coil operable between a de-energized condition and an energized condition where the magnetic coil generates magnetic flux

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

When the magnetic coil is in the energized condition, magnetic drag slows rotation of the sprocket relative to the differential case

Methodology Applied
Scientific EffectMagnetic drag: Magnetic Field

Data Source

PatentEP2635826B1Electronically triggered locking differential
Publication Date: 2020.08.26 EATON INTELLIGENT POWER LTD
  • EP2635826B1 patent drawingFigure 1~2
  • EP2635826B1 patent drawingFigure 3~4
  • EP2635826B1 patent drawingFigure 5

AI summary

An electronically triggered locking differential includes a differential case, at least one pinion gear and a pair of side gears. A clutch pack is disposed between one of the side gears and the differential case and retards relative rotation between the differential case and the side gear. A cam member is disposed adjacent the clutch pack so that the clutch pack engages when the cam member ramps up. An engagement shaft has one end engaged with the cam member and an opposite end extending through the differential case and engaged with a sprocket. A magnetic coil and flux conductor magnetically couple the sprocket to the differential case when the coil is energized. This coupling retards rotation of the engagement shaft and the cam member relative to the gear case, initiating engagement of the clutch pack to lock the differential.