Electric Axle Drive With Planetary Differential for Compact Packaging
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Solution Overview
Problem
Existing electric axle drives for motor vehicles are bulky, heavy, and costly, requiring multiple components like gear stages and differentials, which increase space, weight, and installation complexity.
Innovation Solution
An electric axle drive utilizing a planetary gear set that functions as both a differential and a gear unit, with an intermediate element to reverse the direction of rotation of one output shaft, eliminating the need for additional differentials and gear stages, thereby optimizing space, weight, and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional differentials and gear stages are used in electric axle drives, then speed compensation between vehicle wheels is achieved, but device complexity, weight, and installation space increase
Solution Approach 1:
The patent combines the differential function and gear stage function into a single integrated planetary gear set. The planetary gear set simultaneously provides speed reduction and differential action for speed compensation between wheels, eliminating the need for separate differentials and multiple gear stages. This merging of functions directly reduces device complexity while maintaining speed compensation capability.
Solution Approach 2:
The planetary gear set is designed to perform multiple functions: it acts as both a differential mechanism for speed compensation and as a gear stage for speed reduction. This multi-functionality allows a single component to replace what would traditionally require multiple separate components, thereby reducing overall device complexity and part count.
2Adaptability or versatility
If additional differentials and gear stages are used in electric axle drives, then speed compensation between vehicle wheels is achieved, but weight increases
Solution Approach 1:
By merging the differential and gear stage functions into a single planetary gear set, the total weight of the axle drive is reduced. Instead of having separate differentials and multiple gear stages that would add cumulative weight, the integrated design uses one compact planetary gear set to accomplish both functions simultaneously.
Solution Approach 2:
The planetary gear set serves as a universal component that performs both differential action and speed reduction. This multi-functionality eliminates the need for additional weight-bearing components, as the same planetary gears and carrier structure provide both speed compensation and torque transmission functions.
3Adaptability or versatility
If additional differentials and gear stages are used in electric axle drives, then speed compensation between vehicle wheels is achieved, but installation space increases
Solution Approach 1:
The integration of differential and gear stage functions into a single planetary gear set significantly reduces the installation space required. Instead of accommodating multiple separate components (differential housing, multiple gear stages, shafts), the design fits all functionality within one compact planetary gear assembly, reducing the overall volume occupied by the axle drive.
Solution Approach 2:
The planetary gear set's ability to perform multiple functions in a single compact structure allows for space-efficient packaging. The same gears and components that provide differential action also provide speed reduction, eliminating the need for additional space-consuming components and allowing for a more compact axle drive installation.
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 enables a compact, lightweight, and cost-effective drive system that achieves efficient speed reduction and differential function, allowing vehicle wheels to rotate at different speeds for cornering while maintaining a small turning circle without additional components.
Implementation Method 1
The electric axle drive has exactly one planetary gear set, having exactly one ring gear, exactly one planet carrier and exactly one sun gear as drive unit for the planetary gear set
Data Source
AI summary
An electric axle drive (10) for an axle (16) of a motor vehicle is provided for use on two vehicle wheels (12, 14). The electrical axle drive has an electric machine (18) having a stator (20) and a rotor (22), and a gear set such that torque, is provided by the rotor (22), and is introduced into the planetary gear set (26) and a first output shaft (36), for driving one of the vehicle wheels (12, 14). A second output shaft (40), from which the other vehicle wheel (14) can be driven, is connected in a torque-transmitting manner to the planet carrier (32) as the second output (42) of the planetary gear set (26), via the outputs (38, 42). The respective output torques resulting from the respective drive torques can be dissipated from the planetary gear set (26) for driving the vehicle wheels (12, 14).