Planetary Axle Assembly Layout for Compact Multi-Ratio Torque Transfer
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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 sun gear, planet gears, and a planet gear carrier, along with a shift mechanism that can move between two positions to connect the rotor to either the sun gear or the planet gear carrier, allowing for multiple gear ratios and a compact design by positioning the planetary gear set and transmission on opposite sides of the differential assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a planetary gear set with multiple gear ratios is implemented, then torque transmission efficiency and versatility are improved, but device complexity and overall length increase
Solution Approach 1:
The patent implements a nested planetary gear set where a first planetary gear set and a second planetary gear set are arranged concentrically around a common sun gear. The planet gears of the first planetary gear set are positioned radially outward from the planet gears of the second planetary gear set, creating a compact nested configuration that achieves multiple gear ratios without proportionally increasing overall assembly complexity
Solution Approach 2:
The common sun gear serves multiple functions by being the central element for both the first and second planetary gear sets. This universal component enables the system to achieve multiple gear ratios through different planetary gear configurations while reducing the total number of independent components needed
2Adaptability or versatility
If a planetary gear set with multiple gear ratios is implemented, then torque transmission efficiency and versatility are improved, but the overall length and weight of the axle assembly increase
Solution Approach 1:
The nested arrangement of planetary gear sets allows compact packaging of multiple gear ratios in a radially distributed configuration rather than requiring axial stacking. This nesting reduces the overall length of the axle assembly while maintaining multiple gear ratio capabilities, thereby reducing the weight of moving components
3Volume of moving object
If the planetary gear set and transmission are positioned on opposite sides of the differential assembly, then package space is reduced, but device complexity increases
Solution Approach 1:
The patent transitions from a conventional linear or axial arrangement of components to a three-dimensional spatial configuration where the planetary gear set and transmission are positioned on opposite sides of the differential assembly. This dimensional reorganization optimizes package space utilization while distributing complexity across different spatial zones
Data Source
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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.