Nested Drive Gears for Compact EV Powertrain Torque Vectoring
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Solution Overview
Problem
Existing electric vehicle powertrains face challenges in achieving a compact and efficient arrangement that allows for torque vectoring while maintaining performance and crash considerations.
Innovation Solution
A drivetrain system with nested drive gears and bearings, including a clutch assembly, that allows for compact packaging, torque vectoring, and independent speed and torque control, utilizing taper roller bearings and a seal to transmit axial forces and maintain alignment, and a clutch assembly for locking the outputs to transfer torque between motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional separate drive gear arrangements are used, then each motor has independent control, but the powertrain assembly occupies excessive space and lacks compactness
Solution Approach 1:
The patent implements nested drive gears where the second drive gear is positioned radially within and axially overlaps the first drive gear, creating a compact nested arrangement that reduces the overall volume of the powertrain assembly while maintaining independent motor control capability
Solution Approach 2:
The patent transitions from traditional side-by-side gear arrangements to a three-dimensional nested configuration where gears overlap in both radial and axial dimensions, effectively utilizing spatial volume to reduce the assembly's external footprint
2Volume of moving object
If nested drive gears are used to achieve compactness, then space is reduced, but torque vectoring capability and independent speed control become more difficult to implement
Solution Approach 1:
The patent segments the powertrain into two independent motor-gear units (first motor with first drive gear, second motor with second drive gear) that maintain independent control capability despite being nested together, enabling torque vectoring by independently controlling each motor's speed and torque output
Solution Approach 2:
The patent introduces a clutch assembly as an intermediary mechanism between the nested drive gears that can selectively couple or decouple the two drive gears, providing additional versatility for torque management and speed control configurations
3Volume of moving object
If drive gears are arranged to overlap axially, then compact packaging is achieved, but alignment precision and force transmission requirements increase
Solution Approach 1:
The patent introduces bearings as intermediary support elements between the nested drive gears that precisely locate and align the gears axially and radially, accommodating manufacturing tolerances while ensuring proper meshing and force transmission in the compact nested arrangement
4Loss of energy
If nested shafts and bearings are used, then mechanical efficiency is improved through compact design, but thermal management challenges increase due to reduced space for cooling
Solution Approach 1:
The patent extracts the lubrication and thermal management function into a dedicated system with lubricating grease held in recesses and sealed from the nested gear arrangement, allowing the compact mechanical design to be maintained while providing separate thermal management pathways
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 enables a compact, efficient, and mechanically robust powertrain system that improves off-road capability, thermal management, and mechanical efficiency, allowing for independent control of output shafts and efficient power transfer.
Implementation Method 1
the bearing includes a taper roller bearing for transmitting axial force between the first drive gear and the second drive gear
Implementation Method 2
a seal interfacing with the first drive gear and with the second extension to at least partially seal the recess
Data Source
AI summary
A drivetrain system includes a first drive gear driven by a first motor and a second drive gear driven by a second motor. The first drive gear and the second drive gear are arranged along the axis. The first drive gear includes a first extension and the second drive gear includes a second extension arranged radially within and axially overlapping the first extension. The drivetrain system includes a system of bearings arranged between the first drive gear and the second drive gear, either drive gear and a stationary component, or a combination thereof. In some embodiments, the drivetrain system includes a clutch assembly arranged between the first drive gear and the second drive gear that interfaces to the first drive gear and to the second drive gear. The clutch assembly allows the drive gears to be locked or otherwise engaged to improve torque transfer.