Electric Drive Axle Gearbox With Nested Multi-Stage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric and hybrid vehicles face challenges in accommodating a compact and lightweight gearbox due to space constraints, particularly in electric vehicles where the gearbox and electric motor need to be positioned near the drive wheel axle, requiring a wide gear reduction ratio and limited space for other components like batteries and suspension assemblies.
Innovation Solution
A compact gearbox design featuring a primary shaft with a distribution gear and an auxiliary shaft, allowing the output gear to rotate around the same axis as the primary shaft, enabling a compact and lightweight solution with variable rotational speeds and multiple gear stages, and incorporating roller and needle bearings for high torque and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a wide gear reduction ratio is achieved through multiple reduction stages, then the torque demand at the wheel is fulfilled, but the gearbox occupies more space and leaves limited volume for other components
Solution Approach 1:
The patent implements a nested gear arrangement where gears are positioned concentrically around a central axis. The first gear is rotatably mounted on the input shaft, the second gear is mounted on the output shaft and positioned around the first gear, and the third gear is mounted on the output shaft and positioned around the second gear. This nesting allows multiple reduction stages to be compacted into a small radial space, achieving wide gear reduction ratio without increasing gearbox volume.
Solution Approach 2:
The patent transitions from a linear arrangement of gears to a concentric/circular arrangement around a central axis. By organizing gears in radial layers rather than sequential linear stages, the design achieves multiple reduction ratios within a compact radial footprint, effectively utilizing the third dimension (radial space) to reduce the overall gearbox volume while maintaining multiple reduction stages.
2Force
If a gearbox with multiple reduction stages is used, then the torque demand is met, but the gearbox becomes heavy which reduces vehicle mobility and limits autonomy
Solution Approach 1:
The nested gear configuration allows multiple reduction stages to share common mounting spaces and support structures. Gears are positioned concentrically, enabling compact integration of multiple functional elements into a single compact unit, reducing the overall mass required for housing, mounting brackets, and support components compared to distributed linear arrangements.
Solution Approach 2:
The patent combines multiple gear stages and their support structures into a single integrated compact assembly. The input shaft, output shaft, and multiple gears are arranged to share common mounting points and housing structures, merging what would otherwise be separate components into one unified lightweight assembly.
3Ease of operation
If the gearbox is positioned near the drive wheel axle in electric vehicles, then space for batteries and other components is limited, but the electric motor and gearbox must be accommodated in the vicinity of the drive wheel axle
Solution Approach 1:
The nested gear arrangement concentrates all transmission components within a small radial envelope centered on the output shaft axis. This compact concentric layout allows the entire gearbox assembly to fit within a minimal volume near the drive wheel axle, preserving maximum space for batteries, suspension, and other vehicle components.
Solution Approach 2:
By arranging gears concentrically around the output shaft rather than in a linear sequence, the design minimizes the axial and radial dimensions of the gearbox. This dimensional reorganization allows the gearbox to occupy a compact cylindrical volume near the drive wheel axle, freeing up surrounding space for other essential vehicle components.
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 design achieves a compact and efficient gearbox that meets high-torque and high-speed demands, improving reliability and reducing maintenance needs, while allowing for more space in vehicles for other essential components.
Implementation Method 1
incorporating roller and needle bearings for high torque and reliability
Data Source
AI summary
A gearbox for a vehicle includes a primary shaft configured to rotate about a first axis, a distribution gear, a transmission gear arranged around the primary shaft, an auxiliary shaft configured to rotate around a second axis, an auxiliary output gear and an auxiliary transmission gear arranged around the auxiliary shaft, an output gear arranged around the primary shaft for transmitting a power out of the gearbox, and a gear shift system slidable between at least two positions. The gear shift system is configured to rotationally engage the distribution gear and the output gear for transmitting the power directly from the primary shaft to the output gear, or the distribution gear and the transmission gear for transmitting the power indirectly from the primary shaft to the output gear through the auxiliary shaft.