Differential Assembly with Electromagnetic Torque Vectoring

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Solution Overview

Problem

Existing differential arrangements lack the ability to dynamically change torque distribution to output elements, limiting their application in vehicles for advanced control and stability during cornering and varying terrain conditions.

Innovation Solution

A differential arrangement with at least one output element connected to an electrical device, allowing for dynamic torque control and distribution, utilizing a magnetic three-shaft epicyclic gear with integrated electrical machines to achieve asymmetrical torque distribution and torque vectoring, eliminating the need for mechanical contact and lubrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a classic open differential is used, then the transmission is free from yaw moments and both wheels transmit the same moment, but the torque distribution cannot be dynamically changed and cornering control is limited

Engineering Contradiction:
Improvetorque distribution capabilityVSAvoiddifferential structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical torque distribution mechanism with an electromagnetic system. Electrical machines (motors or generators) are coupled to the differential carrier and output shafts to actively control torque distribution. This substitution enables dynamic torque vectoring without requiring complex mechanical linkages or clutch mechanisms, thereby achieving adaptable torque distribution while maintaining relatively simple differential structure.

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

2Adaptability or versatility

If a limited slip differential is used, then torque can be shifted from the faster rotating wheel to the slower rotating wheel, but steering effects occur during cornering and the system resists steering

Engineering Contradiction:
Improvetorque distribution controlVSAvoidsteering responsiveness
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent incorporates sensors to detect wheel speeds, differential carrier speed, and vehicle state parameters. This feedback information is processed by a control unit that calculates the required torque distribution to achieve desired vehicle dynamics. The electrical machines adjust torque in real-time based on this feedback, enabling precise control that prevents unwanted steering resistance while maintaining torque vectoring capabilities.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from static torque distribution (fixed mechanical limited-slip characteristics) to dynamic torque distribution. Electrical machines coupled to the differential carrier and output shafts can actively modulate torque in real-time based on driving conditions, cornering status, and vehicle speed. This dynamic control allows the system to adapt torque distribution continuously, improving steering responsiveness while maintaining torque vectoring benefits.

Inventive Principle:
Principle #15Dynamics

3Power

If mechanical contact and lubrication are used in differential gears, then power transmission is achieved, but wear and friction losses occur

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidfriction losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent replaces mechanical friction-based torque distribution with an electromagnetic system. Electrical machines coupled to the differential carrier and output shafts use electromagnetic fields rather than mechanical contact to control torque distribution. This substitution eliminates or significantly reduces friction losses and wear associated with traditional mechanical limited-slip mechanisms while maintaining effective power transmission and torque vectoring capabilities.

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

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

Enables targeted torque distribution and improved vehicle stability by dynamically adjusting torque to wheels, reducing wear and friction losses, and allowing for efficient power circulation and reactive power utilization, enhancing cornering performance and reducing installation space and costs.

Implementation Method 1

utilizing a magnetic three-shaft epicyclic gear with integrated electrical machines

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

at least one output element for distributing torque is connected to an electrical device

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP3480493B1Differential assembly
Publication Date: 2022.03.16 DEERE & CO
  • EP3480493B1 patent drawingFigure 1
  • EP3480493B1 patent drawingFigure 2
  • EP3480493B1 patent drawingFigure 3

AI summary

The invention relates to a differential arrangement (24) with at least one input element (20) and at least two output elements (26, 28). At least one output element (26) is connected to at least one electrical device (36) for the distribution of torque.