Multi-step Planetary Gear Drive Device Axial Overlap
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Solution Overview
Problem
Current drive devices for motor vehicles lack a compact and efficient transmission system that effectively distributes drive power to multiple output shafts, resulting in suboptimal power density and transmission ratios.
Innovation Solution
A drive device featuring a transmission device with a first planetary set, a multi-step planetary set, and a differential transmission with second and third planetary sets, where the planetary gears are arranged on carriers to achieve a high transmission ratio and power density, with a spur gear differential configuration for power distribution to two output shafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional transmission system is used, then the structure is simple, but the power density and transmission ratio are suboptimal
Solution Approach 1:
The patent combines multiple planetary gear sets (first planetary set with planetary gears on first planetary carrier, second planetary set with planetary gears on second planetary carrier, and third planetary set) into a single integrated transmission device. The first internal gear is fixed on the housing while the second internal gear is connected to the third planetary carrier, creating a merged structure that achieves high transmission ratios and power density without requiring separate transmission units.
Solution Approach 2:
The transmission device employs a nested arrangement where planetary gears are arranged within planetary carriers, which are themselves connected to other planetary sets. The first planetary carrier connects to the second sun, which connects to the second planetary carrier, creating a nested hierarchy of rotating components that maximize space utilization and power density.
2Adaptability or versatility
If multiple output shafts are added for power distribution, then the power distribution capability is improved, but the device complexity increases
Solution Approach 1:
The transmission device is designed with multi-functionality to serve multiple purposes: it provides power distribution to multiple output shafts (second and third output shafts), achieves high transmission ratios, and maintains a compact structure. The differential transmission section with the third planetary carrier and multiple planetary sets enables the single device to perform both transmission and differential functions simultaneously.
Solution Approach 2:
The patent merges the transmission function and differential function into a single integrated device. The first planetary set handles transmission, while the second and third planetary sets on the third planetary carrier handle differential power distribution to two output shafts, eliminating the need for separate differential gear units.
3Volume of moving object
If a compact transmission system is designed, then the volume is reduced, but the manufacturing complexity increases
Solution Approach 1:
The compact design is achieved through nested arrangement of planetary gears within planetary carriers, which are themselves nested within the housing structure. The first planetary carrier connects to the second sun, which connects to the second planetary carrier, creating a space-efficient nested hierarchy that reduces overall volume while maintaining functional complexity.
Solution Approach 2:
By merging multiple transmission stages and differential functions into a single compact device with shared components (such as the housing that supports both internal gears and the third planetary carrier), the patent reduces the total volume required compared to separate transmission and differential units.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a compact and efficient power distribution system with high transmission ratios, enhancing power density and enabling effective drive power distribution to multiple output shafts, suitable for electric drive axles in motor vehicles.
Implementation Method 1
a first planetary set with a plurality of planetary gears, a multi-step planetary set with a plurality of multi-step planetary gears, and a differential transmission with a second and third planetary set with in each case a plurality of planetary gears
Data Source
AI summary
A drive device includes a drive machine, such as an electric motor, gear reduction planetary gear sets, and a differential. One of the gear reduction planetary gear sets utilizes multi-step planetary gears. The differential is a spur gear differential. To reduce axial length, one of the gearwheels of each multi-step planetary gears axially overlaps with planetary gears of the spur gear differential.