Off-Axis Electric Traction Axle With Compact Epicyclic Transmission
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Solution Overview
Problem
Existing electric traction axles and beams face challenges with bulky electric machines that limit the positioning of other components, necessitating resized transmissions and reducing power and performance due to increased dimensions, undermining versatility in vehicle operating conditions.
Innovation Solution
An off-axis configuration with a parallel shaft reduction system and epicyclic assemblies allows for a compact design, maintaining high torque and power delivery while housing the electric machine separately from transmission elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the electric machine is positioned in an on-axis configuration (coaxial to the axle/beam drive shafts), then the assembly of elements on the axles is facilitated, but the longitudinal dimension of the axle increases, limiting the positioning of other functional elements and requiring resizing of the transmission
Solution Approach 1:
The patent transitions from a one-dimensional on-axis arrangement to a two-dimensional off-axis arrangement. The electric machine is positioned with its axis parallel to but spaced apart from the drive shaft axis, utilizing the radial dimension to accommodate the bulky electric machine without increasing the longitudinal dimension of the axle assembly.
2Ease of operation
If the longitudinal dimension of the axle is increased to accommodate the electric machine, then the electric machine can be properly positioned, but the transmission must be resized, decreasing the power and performance available to the axle
Solution Approach 1:
By utilizing the radial dimension through off-axis positioning, the patent accommodates the electric machine without increasing longitudinal space requirements. This preserves the size of the transmission components and maintains the power and performance characteristics of the original design.
3Length of moving object
If the transmission is resized to fit within the limited longitudinal space, then the axle dimensions are reduced, but the versatility of torque and power provision over an extended interval is undermined
Solution Approach 1:
The off-axis configuration creates sufficient longitudinal space to maintain a transmission designed for extended torque and power versatility. The radial offset provides the necessary clearance along the longitudinal axis while preserving the transmission's ability to deliver varied power characteristics.
4Length of moving object
If the electric machine is positioned off-axis (parallel and spaced apart from the drive shaft axis), then the longitudinal dimensions are reduced and component assembly is facilitated, but the transmission mechanism becomes more complex
Solution Approach 1:
The patent introduces an intermediary transmission mechanism (epicyclic gear system with speed ratio change) that mediates between the off-axis electric machine and the drive shafts. This intermediary mechanism efficiently transfers power while accommodating the spatial offset, managing the complexity through well-established mechanical principles.
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 provides an electric traction axle with reduced longitudinal dimensions, enabling high torque and power delivery, facilitating assembly and lubrication, and maintaining operational versatility across diverse vehicle conditions.
Implementation Method 1
The electric traction axle/beam employs an off-axis configuration where the electric machine's axis is parallel and spaced apart from the axle/beam's longitudinal axis, allowing for reduced longitudinal dimensions while maintaining high torque and power delivery through advanced epicyclic mechanisms
Implementation Method 2
The electric traction axle/beam employs an off-axis configuration where the electric machine's axis is parallel and spaced apart from the axle/beam's longitudinal axis, allowing for reduced longitudinal dimensions while maintaining high torque and power delivery
Data Source
AI summary
An electric traction axle/beam, e-axle/e-beam, for a vehicle comprising at least one electric machine, a pair of drive shafts each connected to a respective wheel of the vehicle and a transmission chain operatively connecting the electric machine to the pair of drive shafts,the transmission chain comprising a first transfer system, a second transfer system, and a differential unit operationally interposed in series between them,the drive shafts being coaxial to a longitudinal axis of the axle, the electric machine being subtended by a parallel and separate axis of the longitudinal axis.