Variable Torque Distribution System with Off-Axis Main Drive

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Solution Overview

Problem

Current systems for torque distribution in motor vehicle axles lack a modular structure with high power density, limiting their efficiency and space utilization.

Innovation Solution

A system featuring a main drive, arranged off-axis relative to the axle, transmitting torque to a differential via an upstream gear stage, which can be either a hypoid gear or a single-stage spur gear, coupled with a torque vectoring motor that uses power-split planetary gears and a load-balancing gear stage for dynamic torque distribution to individual wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional torque distribution systems are used, then torque can be transmitted to drive shafts, but the systems lack modular structure and high power density

Engineering Contradiction:
Improvemodular structureVSAvoidpower density
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The system is divided into modular components: a main drive unit with upstream gear stage, a differential unit with power-split planetary gears, and a torque vectoring motor unit. Each module can be independently designed, manufactured, and maintained, achieving modular structure while maintaining high power density through optimized component integration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The torque vectoring motor is integrated within the differential unit, with the motor shaft directly connected to the planetary gear mechanism. This nested arrangement allows the smaller motor to be housed within the larger differential structure, achieving compact modular design with high power density.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Area of stationary object

If the main drive is arranged on-axis with the axle, then torque transmission is straightforward, but axial installation space is increased

Engineering Contradiction:
Improveaxial installation spaceVSAvoidtorque transmission arrangement
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The main drive is positioned off-axis relative to the axle, utilizing the radial dimension rather than the axial dimension for torque transmission. The upstream gear stage (hypoid or spur gears) transmits torque from the off-axis main drive to the differential unit, reducing axial installation space while maintaining effective torque transmission through three-dimensional gear engagement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Volume of stationary object

If traditional differential designs are used, then torque distribution is simple, but the differential size is limited by available space

Engineering Contradiction:
Improvedifferential sizeVSAvoidtorque distribution mechanism
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

The differential unit combines traditional torque distribution functionality with power-split planetary gear mechanisms and integrated torque vectoring motor control. This merged design enables the differential to perform multiple functions (torque splitting, torque vectoring, and motor integration) within a compact volume, increasing differential size capability while managing complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If torque vectoring motor is continuously activated, then precise torque distribution is achieved, but energy consumption increases

Engineering Contradiction:
Improvetorque distribution precisionVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The torque vectoring motor is activated only when torque redistribution is required (such as during cornering, acceleration, or deceleration), rather than continuous operation. The control system monitors driving conditions and engages the torque vectoring motor periodically when needed, achieving precise torque distribution while minimizing energy consumption during normal straight-line driving.

Inventive Principle:
Principle #19Periodic action

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 configuration reduces axial installation space, allows for larger differentials, and enables efficient torque distribution for improved vehicle handling and energy savings by optimizing gear ratios and reducing unnecessary motor activation during straight driving.

Implementation Method 1

an upstream gear stage, which can be either a hypoid gear or a single-stage spur gear

Methodology Applied
Scientific EffectGear: Gear

Implementation Method 2

two power-split planetary gears, which are followed by a load-balancing gear stage in the form of a planetary gear

Methodology Applied
Scientific EffectPlanetary gear mechanism: Epicyclic Gearing

Data Source

PatentEP2516191B1System for variable torque distribution
Publication Date: 2013.11.06 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP2516191B1 patent drawingFigure 1~2
  • EP2516191B1 patent drawingFigure 3

AI summary

The invention relates to a system (1) for variable torque distribution within at least one axle (3) of a motor vehicle that comprises a main drive (10) and a torque vectoring motor (20).