Nested Shaft Powertrain Assembly With Shared Bearings and Clutch
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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 mechanical efficiency and off-road capability.
Innovation Solution
A drivetrain system with nested drive gears and bearings, including a clutch assembly, that allows for independent speed and torque control, reduces the number of bearings, and provides a compact package with high mechanical efficiency, enabling torque transfer between two electric motors to a single output shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional separate drivetrain arrangements are used for multiple electric motors, then each motor can be independently controlled, but the overall system size and complexity increase
Solution Approach 1:
The patent implements nested drive gears where the second drive gear is positioned radially within the first drive gear, and both share a common rotational axis. This nesting arrangement allows multiple drivetrains to occupy the same spatial envelope, reducing overall system size while maintaining independent motor control capability
Solution Approach 2:
The patent combines multiple drivetrain components into a unified structure with shared elements. Multiple drive gears share common bearings and a common rotational axis, merging what would traditionally be separate assemblies into an integrated unit that reduces the total number of components
2Volume of moving object
If multiple drive gears are arranged in a compact nested configuration, then the system becomes more compact, but thermal management during high-load events becomes more challenging
Solution Approach 1:
The patent segments the drivetrain into multiple independent drivetrains, each with its own motor and drive gear. This segmentation allows for distributed thermal management where each motor-gear assembly can be cooled independently, preventing heat accumulation in a single centralized component while maintaining compact overall dimensions
3Device complexity
If nested drive gears share common bearings, then the number of bearings is reduced, but the bearing load and stress increase
Solution Approach 1:
The patent introduces a clutch assembly as an intermediary mechanism between the nested drive gears. The clutch can selectively engage or disengage torque transfer between the first and second drive gears, allowing the system to distribute bearing loads more effectively and prevent excessive stress accumulation on shared bearings during high-torque operations
Data Source
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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.