Torque Vectoring Device Using Electrical Motor and Planetary Gear Set

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Solution Overview

Problem

Existing torque vectoring devices for vehicles are heavy, expensive, and consume high power due to their mechanical design, which affects rotational speed and increases energy consumption.

Innovation Solution

A torque vectoring device utilizing an electrical motor connected to a differential mechanism on an axle, with a control system that adjusts drive currents based on vehicle state variables, allowing for efficient torque distribution between drive shafts, reducing size and energy consumption by operating at differential rotational speed rather than absolute rotational speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If mechanical gear devices are used to increase rotational speed of drive shafts, then torque vectoring capability is achieved, but device weight and size increase significantly

Engineering Contradiction:
Improvetorque vectoring capabilityVSAvoiddevice weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent replaces traditional mechanical gear devices with an electrical motor system. The electrical motor is connected to the differential mechanism and controlled by control means that receive vehicle state variables. This substitution eliminates heavy mechanical gearing while achieving the same torque vectoring function through electrical actuation, directly resolving the contradiction between torque vectoring capability and device weight.

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

Solution Approach 2:

The invention changes the operational parameters of the torque vectoring system by operating the electrical motor at differential rotational speed rather than absolute rotational speed. This parameter change reduces the speed and torque requirements of the motor, allowing for a more compact and lighter design while maintaining effective torque distribution between drive shafts.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If mechanical gear devices operate at absolute rotational speed, then torque distribution is achieved, but energy consumption increases

Engineering Contradiction:
Improvetorque distribution capabilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent fundamentally changes the operational parameter from absolute rotational speed to differential rotational speed. The electrical motor operates based on the speed difference between left and right drive shafts rather than the absolute speed of the drive shafts themselves. This parameter change dramatically reduces the energy required for torque vectoring, especially during steady-state driving where differential speed is minimal, directly resolving the energy consumption contradiction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Replacing the mechanical gear system with an electrical motor system controlled by differential speed parameters reduces energy losses associated with mechanical friction and inefficiencies. The electrical system can more efficiently convert energy to produce the required torque difference, lowering overall power consumption while maintaining torque distribution capability.

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

3Adaptability or versatility

If mechanical torque vectoring devices are implemented, then driving dynamics are enhanced, but device complexity and cost increase

Engineering Contradiction:
Improvedriving dynamics enhancementVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical gear devices with a more compact electrical motor system. The electrical motor, differential mechanism, and control means form a simpler integrated system compared to traditional mechanical torque vectoring devices. This substitution reduces the number of mechanical components, simplifies the overall device architecture, and lowers manufacturing costs while maintaining the ability to enhance driving dynamics through torque vectoring.

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

4Ease of operation

If electrical motor operates at absolute rotational speed, then torque control is achieved, but device size and energy consumption increase

Engineering Contradiction:
Improvetorque control capabilityVSAvoiddevice size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent changes the operational parameter from absolute rotational speed to differential rotational speed for the electrical motor. This parameter change allows the motor to operate at lower speeds and with reduced power requirements, enabling a more compact motor design. The differential mechanism translates this differential speed operation into effective torque control, achieving torque control capability with a smaller device volume.

Inventive Principle:
Principle #35Parameter changes

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 results in a compact, energy-efficient torque vectoring device that enhances driving dynamics, reduces energy losses, and allows for real-time traction control on surfaces with inhomogeneous friction, while also enabling regenerative braking to further decrease energy consumption.

Implementation Method 1

an electrical power source connected to an electrical motor, said electrical motor being connectable to said axle for torque vectoring between said first drive shaft and said second drive shaft

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP2738425B1A device for torque vectoring
Publication Date: 2019.12.25 BORGWARNER SWEDEN AB
  • EP2738425B1 patent drawingFigure 1~3
  • EP2738425B1 patent drawingFigure 4~6
  • EP2738425B1 patent drawingFigure 7

AI summary

A device for torque vectoring in a wheeled vehicle is provided. The device comprises a differential mechanism (130, 220a, 220b, 320, 406) arranged on an axle (110, 210, 310, 402) having a first drive shaft (214, 314, 402L) and a second drive shaft (216, 316, 402R), an electrical power source (424) connected to an electrical motor (140, 230, 330, 410), said electrical motor (140, 230, 330, 410) being connectable to said axle (110, 210, 310, 402) for torque vectoring between said first drive shaft (214, 314, 402L) and said second drive shaft (216, 316, 402R), wherein said electrical motor (330) is connected to said first drive shaft (314) and said second drive shaft (316) by means of a planetary gear set (340), and control means (150, 420, 430, 440) connected to said power source (424) and configured to receive a plurality of variables (442, 444) representing the current vehicle state and to determine drive currents (412) being dependent on said variables (442, 444), wherein said drive currents (412) are supplied to said electrical motor (140, 230, 330, 410) from said power source (424) for introducing a torque increase to either one of said first or second drive shafts (214, 216, 314, 316, 402L, 402R) and a corresponding torque decrease to the other one of said first or second drive shafts (214, 216, 314, 316, 402L, 402R).