Electric Drive Axle with Nested Planetary Reduction Gear
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Solution Overview
Problem
Existing work machines with electric drive systems lack efficient and compact powertrain configurations that enable high reduction ratios and efficient energy distribution, particularly in compact designs, limiting their efficiency and size optimization.
Innovation Solution
A drive axle configuration featuring a spur gear stage with a differential gear unit and an additional planetary reduction gear unit, coupled with an electric drive machine, which allows for high reduction ratios and efficient energy distribution, enabling compact and efficient operation. This configuration includes a transfer case for drive force transfer between axles and independent power electronics units for each stator section, allowing for regulated energy feeding and phase synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional electric drive machine is used in work machines, then the drive system can be simplified compared to hydraulic systems, but the machine dimensions and powertrain size cannot be optimized efficiently
Solution Approach 1:
The patent applies nesting by integrating the reduction gear unit directly into the drive axle housing, where the planetary gear mechanism is contained within the axial space. This nested configuration allows the powertrain components to be compactly arranged without increasing overall machine dimensions, resolving the contradiction between drive efficiency and compact size.
Solution Approach 2:
The patent utilizes the radial dimension by positioning the planetary gear mechanism with sun gear, planetary gears, and ring gear in a radial arrangement around the input shaft. This dimensional optimization enables high reduction ratios without extending the axial length, thus maintaining compact machine dimensions while achieving efficient power transmission.
2Force
If high reduction ratios are implemented in the powertrain, then torque multiplication is improved, but the transmission system becomes more complex
Solution Approach 1:
The patent replaces conventional multi-stage reduction mechanisms with a single-stage planetary gear unit that achieves high reduction ratios through the inherent mechanical advantage of the sun-planet-ring gear configuration. This substitution maintains torque multiplication capability while significantly reducing transmission system complexity compared to traditional multi-stage arrangements.
Solution Approach 2:
The planetary gear unit serves multiple functions simultaneously: it provides high reduction ratio, torque multiplication, and compact packaging in a single integrated mechanism. The differential gear unit also performs dual functions of power distribution and steering enablement, reducing overall system complexity while achieving desired performance.
3Use of energy by moving object
If independent power electronics units are provided for each stator section, then energy distribution control is improved, but the device complexity increases
Solution Approach 1:
The patent segments the power electronics system into independent control units for each stator section, allowing separate energy distribution control. This segmentation enables optimized energy management for each motor phase while maintaining overall system efficiency, resolving the contradiction between control precision and system complexity through modular architecture.
Data Source
AI summary
A drive axle for a work machine for driving wheels that are coupled to the drive axle. The drive axle includes a spur gear stage with an input shaft. A differential gear unit couples to the spur gear stage and to the wheels via wheel drive shafts. The drive axle further includes a reduction gear unit with an output element couples to the input shaft of the spur gear stage—and an input element which couples to an output shaft of an electric drive machine.