Electric Axle Layout With Lateral Motor Offset for Suspension Clearance
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Solution Overview
Problem
Vehicle platform electrification poses challenges with space constraints for electric axles due to the carry-over of hybrid powertrain components, particularly affecting electrified rigid beam axles and suspension systems.
Innovation Solution
An electric axle assembly with an electric machine laterally positioned between drive wheels and axially offset from their rotational axes, utilizing a pseudo dual-layshaft arrangement and a locking differential, allowing for compact packaging that avoids interference with vehicle frames during suspension movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the electric machine is positioned in a conventional location in the axle assembly, then the packaging is simpler, but it interferes with the vehicle frame during suspension jounce and rebound
Solution Approach 1:
The electric machine is positioned in a lateral direction between the drive wheels rather than in the conventional axial direction, utilizing the lateral dimension of the axle assembly. This dimensional repositioning allows the electric machine to be located in a space that does not interfere with suspension movements, thereby resolving the conflict between packaging simplicity and suspension performance.
2Device complexity
If hybrid powertrain components are carried over during electrification, then investment costs and project management complexity are reduced, but space constraints are imposed on the electric axle
Solution Approach 1:
By repositioning the electric machine laterally between the drive wheels and offsetting its rotational axis from the wheel rotational axes, the design utilizes previously unused lateral space in the axle assembly. This dimensional approach allows accommodation of the electric machine without increasing the axial footprint, thereby maintaining compatibility with existing hybrid powertrain component layouts.
Solution Approach 2:
The electric machine's rotational axis is deliberately offset from the rotational axes of the drive wheels, creating an asymmetric configuration. This asymmetric positioning allows the electric machine to occupy lateral space without interfering with the symmetric arrangement of other powertrain components, effectively resolving the space constraint issue.
3Device complexity
If other vehicle components such as the vehicle frame are positioned conventionally, then the overall vehicle structure is simpler, but they pose space constraints on the electric drive unit during suspension movements
Solution Approach 1:
The electric machine is relocated to the lateral dimension between the drive wheels, offset from the axial dimension where suspension components operate. This dimensional separation allows the conventional vehicle frame and suspension components to remain in their traditional positions while the electric machine occupies a non-interfering lateral space, maintaining simple vehicle structure while providing adequate space for the electric drive unit.
Data Source
AI summary
An electric axle is provided. The electric axle includes, in one example, an electric machine rotationally coupled to a layshaft via a first gear reduction and a differential rotationally coupled to the first gear reduction, a first axle shaft, and a second axle shaft. In the electric axle, the electric machine is positioned laterally between at least two drive wheels that are rotationally coupled to the first axle shaft and the second axle shaft and a rotational axis of the electric machine is axially offset from rotational axes of the at least two drive wheels.