Integrated Electric Motor Torque Transfer Unit
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Solution Overview
Problem
Current power transmission systems in four-wheel drive vehicles lack advanced technology for adaptive torque transfer and efficient operation across varying vehicle conditions, relying on mechanical clutch actuation and limited electric assistance.
Innovation Solution
An axle assembly with a power transmission device incorporating a friction clutch and an electric motor, where the electric motor can provide positive or negative torque input, and the clutch can be actuated electronically to manage torque transfer between input and output members, enabling multiple drive modes including electric motor assist, regenerative braking, and sole electric drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electric motor is integrated into the torque transfer unit, then adaptability and versatility of drive modes are improved, but device complexity increases
Solution Approach 1:
The electric motor is integrated directly into the torque transfer unit by mounting the motor assembly onto the housing, with the motor shaft coupled to the input member. This merging of functions allows the same device to provide both mechanical torque transfer via clutch and electric torque assistance, enabling multiple drive modes (2WD, 4WD, electric motor assist, regenerative braking) without requiring separate systems.
2Extent of automation
If electronic clutch actuation is implemented, then ease of operation and automation are improved, but device complexity increases
Solution Approach 1:
The clutch actuation mechanism is replaced from a purely mechanical system to an electronically-controlled system. An electric motor-driven actuator is coupled to the clutch mechanism, allowing electronic control signals to regulate clutch engagement and disengagement. This substitution enables automated torque transfer control based on vehicle operating conditions, improving responsiveness and ease of operation while reducing the need for manual mechanical linkages.
3Loss of energy
If regenerative braking capability is added, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The electric motor integrated in the torque transfer unit serves multiple functions: it provides torque assistance during acceleration, enables regenerative braking by operating as a generator, and can function as a standalone drive source. This multi-functionality allows the same component to recover braking energy and convert it to electrical energy for storage, improving overall energy efficiency without requiring a separate dedicated regenerative braking 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 adaptive torque management across different drive modes, improving vehicle traction and efficiency by integrating electric motor assistance and regenerative capabilities, enhancing the vehicle's ability to respond to dynamic operating conditions.
Implementation Method 1
An electric motor comprising a coil and a plurality of magnets is provided on the axle assembly. In one example, the coil is disposed on the housing and the magnets are disposed on the second clutch member. The coil can be selectively energized to provide one of a positive or negative torque input to the output member.
Implementation Method 2
A friction clutch is disposed in the housing and can be actuated to selectively transfer torque between the input member and the output member.
Data Source
AI summary
An axle assembly comprises a power transmission device including a housing having a cylindrically shaped sidewall. The power transmission device selectively communicates rotatable motion from an input member to an output member. A frictional clutch is disposed in the housing and includes a drum. A first and a second axle shaft selectively drive a first and a second drive wheel, respectively. A differential selectively transfers drive torque from the output member to at least one of the first and second axle shafts. An electric motor comprising a coil and a plurality of magnets is provided on the axle assembly. In one example, the coil is disposed on the housing and the magnets are disposed on the drum. The coil is configured to selectively energize to provide one of a positive or negative torque input to the output member.