Torque Vectoring Device With Integrated Planetary Brake
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Solution Overview
Problem
Conventional torque vectoring devices for vehicles increase unsprung load and vibrations due to heavy brake devices, which are necessary for controlling torque split ratio between drive wheels.
Innovation Solution
A torque vectoring device with a downsized brake system that applies braking force through a rotary member connected to the drive motor's output shaft, using planetary gear units and a differential motor to distribute torque, and an electromagnetic brake mechanism to control frictional contact for braking, reducing the need for separate brake devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional brake devices with rotary members, friction members, and hydraulic actuators are used to control braking force on drive wheels, then sufficient braking force can be ensured, but the brake device weight increases significantly
Solution Approach 1:
The brake device is merged with the differential unit by integrating the friction member into the reaction element structure. The reaction element serves dual functions: establishing reaction torque for differential operation and providing a friction surface for braking. This consolidation eliminates separate brake components while maintaining both differential and braking functions.
Solution Approach 2:
The reaction element is designed with multi-functionality, serving as both a structural component for torque reaction in the differential unit and as a brake friction surface. This allows the same component to fulfill multiple roles: mechanical support for differential operation and friction surface for braking force generation.
2Force
If heavy brake devices with rotary members and hydraulic actuators are installed on drive wheels, then adequate braking performance is achieved, but the unsprung load of the vehicle increases
Solution Approach 1:
The brake friction member is integrated into the reaction element of the differential unit, which is already part of the driven mechanism. This merger eliminates the need for separate brake assemblies on drive wheels, reducing unsprung mass while maintaining braking capability through the combined differential-brake system.
3Ease of operation
If conventional separate brake devices are used for each drive wheel, then individual wheel braking control is achieved, but the overall vehicle vibration increases
Solution Approach 1:
The brake friction member is integrated into the reaction element structure of the differential unit, creating a unified brake-differential assembly. This integration reduces the number of separate braking components and mounting points, thereby reducing vehicle vibrations while maintaining the ability to control braking force distribution to individual drive wheels through differential motor torque control.
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 unsprung load, stabilizes vehicle behavior, and improves comfort by eliminating the need for heavy brake devices, while allowing for adjustable brake torque sharing and reduced power loss through thermal management.
Implementation Method 1
a brake device that is contacted frictionally to the rotary member to establish a braking force
Data Source
AI summary
A torque vectoring device has a downsized brake device for stopping drive wheels. The torque vectoring device comprises: a drive motor; a differential unit including a first planetary gear unit connected to a right drive wheel, and a second planetary gear unit connected to a left drive wheel; a differential motor that applies torque to any one of reaction elements; a torque reversing mechanism that transmits torque between the reaction elements while reversing; a rotary shaft connecting input elements; a rotary member that transmits torque of an output shaft of the drive motor; and a brake device that is contacted frictionally to the rotary member to establish a braking force.