Off-Axis Electric Traction Axle Layout for Compact High-Torque Drive
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Solution Overview
Problem
Existing electric traction axles/beans face challenges in reducing dimensions while maintaining a wide operational range of torque and power, which is essential for diverse vehicle operating conditions.
Innovation Solution
The electric traction axle/beam employs an off-axis configuration with a speed ratio change system and a differential unit, allowing for a compact design that maintains high torque and power delivery through epicyclic mechanisms and transfer systems.
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 axle is facilitated, but the longitudinal dimension of the axle increases, limiting the positioning of other functional elements
Solution Approach 1:
The patent transitions from a one-dimensional coaxial arrangement to a three-dimensional off-axis configuration. The electric machine is positioned with its axis offset from and at an angle to the drive shaft axis, utilizing spatial dimensions to reduce the longitudinal footprint while maintaining functional connectivity through bevel gears and intermediate shafts.
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 versatility of torque and power provision over an extended interval is undermined due to space constraints on other components
Solution Approach 1:
The patent incorporates a variable ratio transmission system with selectable gear sets that allow dynamic adjustment of torque and power delivery characteristics. This enables the system to adapt to different vehicle operating conditions (traction, braking, steering) without requiring increased longitudinal dimensions, as the gear selection mechanism optimizes performance within the available space.
3Length of moving object
If the electric machine is resized to fit within the constrained longitudinal dimension, then the axle dimensions are reduced, but the power and performance available to the axle or beam decreases
Solution Approach 1:
The patent employs a compact off-axis gear train arrangement where bevel gears, intermediate shafts, and differential components are nested within each other in three-dimensional space. This nesting allows the electric machine to maintain its power-producing dimensions while the overall axle assembly fits within reduced longitudinal constraints, as components are arranged in multiple spatial layers rather than linear sequence.
Data Source
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AI summary
An electric traction axle/beam, e-axle/e-beam, (1) for a vehicle comprising at least one electric machine (2), a pair of drive shafts (4', 4") each connected to a respective wheel of the vehicle and a transmission chain operatively connecting the electric machine (2) to the pair of drive shafts (4', 4''), the transmission chain comprising a first transfer system (5), a second transfer system (7), and a differential unit (8) operationally interposed in series between them, the drive shafts (4', 4") being coaxial to a longitudinal axis (A) of the axle (1), the electric machine (2) being subtended by a parallel and separate axis (B) of the longitudinal axis (A).