Nested Planetary EV Drive Unit for More Gears in Less Space
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Solution Overview
Problem
Existing drive units for vehicles lack the ability to increase the number of gears while maintaining compactness and energy efficiency, particularly in electric vehicles.
Innovation Solution
A drive unit comprising a single electric machine and a manual gearbox with multiple shift elements and planetary gear sets, allowing for a higher number of gears through interlocking shift elements and a compact design, including a differential and planetary gear sets to optimize energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of gears is increased in existing drive units, then the transmission ratio range is improved, but the device complexity and installation space increase
Solution Approach 1:
The patent implements nesting by placing the first planetary gear set inside the second planetary gear set, with the first sun shaft positioned within the second sun shaft and the first hollow gear shaft nested within the second hollow gear shaft. This nested configuration allows multiple gears to be achieved within a compact structure without proportionally increasing device complexity or installation space.
Solution Approach 2:
The common hollow gear shaft serves multiple functions by being connected to both planetary gear sets and participating in multiple gear formation operations. This single component enables the system to achieve multiple transmission ratios through different combinations of shift elements, reducing the need for separate dedicated components for each gear.
2Adaptability or versatility
If multiple planetary gear sets are used to increase the number of gears, then the transmission capability is improved, but the weight and installation space increase
Solution Approach 1:
The first planetary gear set is nested within the second planetary gear set, allowing both gear sets to occupy overlapping spatial volumes. This arrangement achieves multiple transmission ratios without proportionally increasing the overall volume and weight of the drive unit.
Solution Approach 2:
The patent merges several components into common structures: a common sun shaft for both planetary gear sets, a common hollow gear shaft, and a common web shaft. This merging reduces the total number of separate components, thereby reducing weight while maintaining the capability for multiple gears.
3Volume of moving object
If a compact design is implemented to reduce installation space, then the vehicle integration is improved, but the number of gears is limited
Solution Approach 1:
The nested configuration of planetary gear sets allows the system to achieve multiple gears within a reduced installation space. The first planetary gear set is positioned within the second, maximizing space utilization while maintaining six forward gears and reverse gear capability.
Solution Approach 2:
The patent utilizes radial arrangement of planetary gears around common shafts to achieve multiple transmission ratios without increasing axial length. This dimensional approach allows compact design while maintaining versatility.
Data Source
AI summary
A drive unit for a vehicle includes an electric machine and a manual gearbox with at least a first shift element, a second shift element, a third shift element and two planetary gear sets coupled to one another and each having a sun shaft, a hollow gear shaft, and a web shaft. The second hollow gear shaft is connected rotationally fixed to the first web shaft. The first sun shaft is connected to a stationary component. In the respective actuated states, the first shift element locks the first planetary gear set to shift a first gear, the second shift element connects the first hollow gear shaft to the second web shaft to shift a second gear, and the third shift element connects the first hollow gear shaft to the second sun shaft to shift a third gear.