Planetary Gear All-Wheel Drive Torque Vectoring
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Solution Overview
Problem
Existing all-wheel drive systems face inefficiencies in fuel consumption and driving characteristics, particularly in controlling wheel slip between the front and rear axles, often relying on frictional clutches that increase complexity and response time.
Innovation Solution
The proposed system employs a planetary gear set with an electrical motor connected to a gearbox output shaft or ground via a coupling, allowing for fast and accurate torque allocation between the front and rear axles, eliminating the need for friction clutches and enabling various drive modes, including longitudinal torque vectoring and hybrid all-wheel drive, using switchable or non-switchable couplings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frictional clutches are used to control wheel slip between front and rear axles, then the system can provide all-wheel drive functionality, but the response time increases and system complexity increases
Solution Approach 1:
The patent replaces frictional clutches with an electrical motor connected to a planetary gear set. The electrical motor provides direct electromagnetic control of torque distribution between front and rear axles, eliminating the mechanical friction-based slip control mechanism. This substitution reduces response time because electrical motors can adjust torque instantly through electronic control signals, whereas frictional clutches require mechanical engagement and slip modulation that takes longer to respond.
2Reliability
If frictional clutches are used to control wheel slip between front and rear axles, then the system can provide all-wheel drive functionality, but the device complexity increases
Solution Approach 1:
The patent extracts and removes the frictional clutch mechanism from the drivetrain, replacing it with an electrical motor coupled to a planetary gear set. This extraction eliminates the complex friction-based torque modulation mechanism while maintaining the essential function of controlling wheel slip through direct electromagnetic torque application to the axles.
Solution Approach 2:
The patent substitutes the mechanical frictional clutch system with an electrical motor system. The electrical motor, combined with the planetary gear set, provides a more compact and controllable mechanism for torque distribution. The substitution reduces device complexity by replacing multiple mechanical components (clutch plates, friction surfaces, actuation mechanisms) with an electrical motor that can be controlled through simple electronic signals.
3Reliability
If conventional all-wheel drive systems are used, then basic drive functionality is provided, but fuel consumption increases and energy efficiency decreases
Solution Approach 1:
The patent implements dynamic torque distribution between front and rear axles using an electrical motor controlled by a control unit. The system continuously adjusts torque allocation based on actual driving conditions, vehicle speed, acceleration demands, and wheel slip detection. This dynamic control allows the system to operate in optimal efficiency modes (such as front-wheel or rear-wheel drive when conditions permit) while maintaining all-wheel drive capability when needed, thereby reducing overall energy consumption compared to conventional systems that may continuously engage all wheels.
Solution Approach 2:
The patent changes the operational parameters of the drivetrain by using an electrical motor to vary torque output and distribution ratios between axles. The control unit monitors multiple parameters (wheel speed, vehicle acceleration, throttle position) and dynamically adjusts motor torque and planetary gear set configuration to optimize energy efficiency. This parameter-based control enables the system to minimize fuel consumption by engaging electric torque assistance only when necessary and adjusting the degree of all-wheel drive engagement continuously.
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 solution significantly reduces response time and improves torque accuracy, decreases fuel consumption, and enhances energy efficiency by synchronizing rotational speeds, while maintaining low system complexity and eliminating the need for friction clutches.
Implementation Method 1
an electrical motor being connected to a first axle of a planetary gear set arranged at an output side of a vehicle gearbox
Implementation Method 2
a planetary gear set with an electrical motor connected to a gearbox output shaft or ground via a coupling, allowing for fast and accurate torque allocation between the front and rear axles
Data Source
AI summary
The present disclosure refers to an all-wheel drive system (10) for a vehicle (12), including: an electrical motor (24) being connected to a first axle (26) of a planetary gear set (28) arranged at an output side (30) of a vehicle gearbox (32), and a second axle (34) of the planetary gear set (28) being connected or connectable to the gearbox output shaft (36) or to ground (G) by a coupling (I).