Multi-speed Electric Drive Axle with Planetary Gear Set
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Solution Overview
Problem
Existing electric drive axles for vehicles lack a compact and lightweight design that can generate multiple gear ratios, limiting their efficiency and versatility in various driving conditions.
Innovation Solution
The electric drive axle incorporates a planetary gear set with a differential and clutches to facilitate multiple gear ratios, allowing for a compact and lightweight configuration that can shift between different ratios for optimal performance in various applications, including highway driving and off-roading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multi-speed gearbox is implemented in an electric drive axle, then gear ratio versatility is improved, but device complexity and weight increase
Solution Approach 1:
The patent employs a planetary gear set where planet gears are nested around a sun gear, with the annulus surrounding the planet gears. This nested configuration allows multiple gear ratios to be achieved within a compact structure by selectively engaging different components (sun gear, planet gears, annulus) through clutches, without requiring separate gear trains for each ratio.
Solution Approach 2:
The planetary gear set serves multiple functions: it provides multiple gear ratios (first and second gear ratios), enables direct drive mode, and maintains a compact layout. The same planetary components are used to achieve different gear ratios by changing which elements are engaged, rather than using separate mechanisms for each ratio.
2Adaptability or versatility
If a planetary gear set with multiple clutches is used, then multiple gear ratios are achieved, but weight increases
Solution Approach 1:
The planetary gear arrangement nests multiple gears in a compact configuration where planet gears orbit a sun gear within an annulus, achieving multiple gear ratios in a space-efficient manner that minimizes overall weight compared to sequential gear trains.
Solution Approach 2:
The patent combines the differential function with the multi-speed gearbox function in a single integrated assembly. The planetary gear set and differential share common components and housing, eliminating the need for separate differentials and reducing overall weight.
3Adaptability or versatility
If clutches are added to facilitate gear ratio changes, then adaptability improves, but device complexity increases
Solution Approach 1:
The system dynamically switches between different gear ratios and direct drive modes by engaging and disengaging clutches based on operating conditions. The clutch control system adapts to different driving scenarios (highway driving, off-roading) by selecting appropriate gear ratios, providing dynamic adaptability without requiring complex mechanical reconfiguration.
Data Source
AI summary
A drive axle of a vehicle includes an electric motor having an output shaft. At least one of a gear and a planetary gear set is operably connected to the output shaft of the electric motor. The at least one of the gear and the planetary gear set is operably connected to a differential configured to transfer torque to two axle half shafts of the vehicle. At least one clutch configured to facilitate a plurality of gear ratios between the electric motor and the differential.