Electric Axle Planetary Gear Layout for Compact Multi-Ratio Drive
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Solution Overview
Problem
Existing axle assemblies with electric motor modules and planetary gear sets face challenges in providing a compact and efficient torque transmission system that allows for multiple gear ratios while maintaining a reduced overall length and weight.
Innovation Solution
The axle assembly incorporates a planetary gear set with a shift mechanism that connects the electric motor to the countershaft and differential assembly through a drive pinion, utilizing a support module with arms and a center support to position the planet gear carrier and countershaft, allowing for adjustable gear ratios and a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a planetary gear set is used to provide multiple gear ratios, then the gear ratio variability is improved, but the device complexity increases
Solution Approach 1:
The patent combines the planetary gear set and countershaft transmission into a single integrated assembly where the planetary ring gear serves as the countershaft support. This merging of functions reduces the number of separate components and simplifies the overall structure while maintaining multiple gear ratio capabilities through the planetary mechanism.
Solution Approach 2:
The planetary ring gear performs multiple functions: it acts as a gear in the planetary set, provides support for the countershaft, and serves as a structural element of the housing. This multi-functionality reduces the total number of components needed while achieving the desired gear ratio variability.
2Volume of moving object
If the planetary gear set and transmission are positioned on opposite sides of the differential assembly, then the package space is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent arranges the planetary gear set and transmission components in a distributed spatial configuration around the differential assembly rather than stacking them linearly. By utilizing opposite sides and three-dimensional spacing, the design achieves compact packaging while maintaining adequate alignment tolerances through strategic component placement.
3Length of moving object
If a compact design is implemented to reduce overall length, then the length is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The transmission assembly is divided into modular segments including the planetary gear set, countershaft with connecting gear, and drive pinion, which can be manufactured and assembled separately then integrated. This segmentation allows for simplified manufacturing of individual components while achieving a compact overall assembly through precise modular integration.
Data Source
AI summary
An axle assembly that has an electric motor, a countershaft, a planetary gear set, a drive pinion, and a differential assembly. The electric motor has a rotor that is rotatable about a rotor axis. The planetary gear set operatively connects the rotor to the countershaft. The drive pinion operatively connects the differential assembly to the countershaft.