Locking Differential With Discontinuous Coil Brake Actuation

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Solution Overview

Problem

Existing differential assemblies for motor vehicles lack an effective electromagnetic locking mechanism that can prevent differential rotation of output shafts without continuous electromagnetic coils, which are inefficient and not suitable for all applications.

Innovation Solution

A locking differential assembly with a discontinuous electromagnetic coil that actuates a brake plate to create a frictional contact with a brake disc, generating an opposing torque force to lock the differential rotation, utilizing a dog clutch mechanism and a position sensor for bi-stable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a continuous electromagnetic coil is used to actuate the locking mechanism, then the locking mechanism can be actuated, but the energy consumption increases and the device complexity increases

Engineering Contradiction:
Improvelocking mechanism actuationVSAvoidelectromagnetic coil energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The continuous electromagnetic coil is divided into multiple discontinuous coil segments arranged around the brake disc circumference. This segmentation reduces the total amount of wire and active electromagnetic material required, thereby reducing energy consumption while still providing sufficient electromagnetic force to actuate the brake plate and engage the locking mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using a complete continuous coil around the entire circumference, only partial coil segments are used at strategic positions. These segments provide just enough electromagnetic force to actuate the locking mechanism, avoiding the excessive energy consumption of a full continuous coil while maintaining reliable operation.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If a continuous electromagnetic coil is used around the brake disc, then the electromagnetic force is distributed, but the manufacturing complexity and material usage increase

Engineering Contradiction:
Improveelectromagnetic force distributionVSAvoidelectromagnetic coil structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electromagnetic coil is segmented into discrete sections rather than forming a continuous ring. Each segment is independently positioned to provide electromagnetic force at critical points around the brake disc, simplifying manufacturing and assembly while maintaining effective force distribution for reliable locking mechanism actuation.

Inventive Principle:
Principle #1Segmentation

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 effectively prevents differential rotation while being energy-efficient and adaptable, ensuring stable locking and unlocking positions without continuous power consumption.

Implementation Method 1

an electromagnetic coil. The electromagnetic coil actuates a brake plate, the brake plate comes into frictional contact with a brake disc

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The brake plate comes into frictional contact with a brake disc. The friction creates a second torque force which is an opposing torque force to the first torque force

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3841317B1Locking differential
Publication Date: 2023.06.21 LINAMAR CORPORATION
  • EP3841317B1 patent drawingFigure 1
  • EP3841317B1 patent drawingFigure 2
  • EP3841317B1 patent drawingFigure 3~4

AI summary

Disclosed is a locking differential assembly which includes a differential case, a first output shaft and a second output shaft. Further included is a first side gear non- rotatably coupled to the first output shaft and a second side gear non-rotatably coupled to the second output shaft. A differential pin is also included, the differential pin having differential gears. The differential gears are rotatably supported by the differential case and drivingly engaged with the first and second side gears to allow differential rotation thereof. Also included is a locking mechanism, the locking mechanism being actuated when a first torque force is applied to a drive cam and a driven cam. Finally included is an electromagnetic coil. The electromagnetic coil actuates a brake plate, the brake plate comes into frictional with a brake disc. Furthermore the electromagnetic coil is discontinuous around the circumference of the brake disc.