Torque Vectoring Driveline Assembly with Segmented Wheel-End Reducers
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Solution Overview
Problem
Conventional electric vehicle driveline assemblies face challenges due to heavy torque loading and structural requirements, leading to high mass and bulky packaging, particularly because torque vectoring hardware must withstand high final drive torque.
Innovation Solution
A driveline assembly with a differential coupled to an electric motor, featuring primary shafts with reducers and clutches that allow for torque vectoring by shifting between locked and unlocked positions, and upshift clutches that adjust gear ratios to provide high speed and low torque or low speed and high torque outputs, positioning torque multiplication near the wheel outputs to reduce overall mass and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If final drive gearing is positioned adjacent to the electric motor to transmit torque, then torque transmission is achieved, but the torque vectoring hardware must withstand high final drive torque leading to heavy mass and bulky packaging
Solution Approach 1:
The driveline is segmented into multiple functional sections: the electric motor section, the differential section, and the wheel-end reducer sections. By dividing the torque transmission path into discrete segments with independent gear reduction stages, the torque vectoring hardware at each wheel end only needs to handle reduced torque levels rather than the full final drive torque, thereby reducing mass while maintaining power transmission capability
Solution Approach 2:
The patent redistributes gear reduction functionality from a single location (adjacent to motor) to multiple locations along the torque path (at each wheel end). This spatial redistribution allows torque vectoring hardware to be positioned where it operates at lower torque levels, effectively reducing the dimensional requirements and mass of each individual torque vectoring unit while achieving the same overall torque multiplication
2Force
If a gear reducer is positioned between the output shaft and differential for providing gear reduction, then torque loading on primary axles is reduced, but the overall package space and mass requirements remain high
Solution Approach 1:
Instead of using a single large gear reducer between the motor and differential, the system segments the gear reduction into multiple smaller stages distributed at each wheel end. Each wheel-end reducer handles a portion of the total gear reduction ratio, which reduces the torque loading on individual components and allows for more compact packaging of each reduction stage
Solution Approach 2:
The system employs dynamically selectable gear ratios through the clutch mechanisms in the wheel-end reducers. This allows the driveline to adaptively change the gear reduction ratio based on driving conditions, optimizing torque delivery while maintaining a compact physical footprint that would be impossible with a fixed-ratio single-stage reducer
3Power
If torque vectoring hardware is designed to withstand high final drive torque, then torque transmission capability is ensured, but the system complexity and cost increase
Solution Approach 1:
The torque vectoring system is segmented into independent wheel-end units, each with its own reducer and clutch mechanism. This modular segmentation allows each unit to be designed and optimized for lower torque levels, simplifying the overall system architecture while maintaining the capability to provide independent torque control to each wheel
Solution Approach 2:
Instead of designing the entire torque vectoring system to handle maximum final drive torque at all times, the patent uses partial action by engaging clutch mechanisms only when torque vectoring is required. The wheel-end reducers provide gear reduction continuously, but the active torque vectoring control is applied selectively, reducing system complexity while maintaining full torque transmission capability when needed
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 results in a low-cost, low-mass, and packagable torque vectoring system that efficiently manages torque distribution, reducing the overall size and weight of the driveline assembly while enabling effective torque vectoring during both high and low range drive operations.
Implementation Method 1
Each reducer includes a sun gear fixed about the primary shaft for rotating with the primary shaft. A plurality of planet gears are meshed with and rotatable about the sun gear. A ring is positioned about and meshed with the planet gears.
Data Source
AI summary
A driveline assembly including a pair of reducers each having a sun gear fixed about a primary shaft. A plurality of planet gears are meshed with and rotatable about the sun gear. A ring is positioned about and meshed with the planet gears. A planet carrier is connected to a center of each of the planet gears and fixed to a wheel output. A low gear clutch is moveable between an engaged position fixing the ring to a ground in the engaged position, and a disengaged position disconnecting the ring from the ground. An upshift clutch is moveable between a contact position fixing the primary axle to the wheel output, and a released position disconnecting the primary axle from direct connection with the wheel output. A controller selectively shifts the center clutch, the low gear clutch and the upshift clutch. Methods of using the driveline assembly are also provided.