Modular Multi-Speed E-Axle Layout for Compact Gear Selection
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Solution Overview
Problem
Existing electric drive axles face challenges related to axle assembly packaging, gear selectability, and structural integrity, often making tradeoffs between gearbox compactness and gear range.
Innovation Solution
A multi-speed and multi-reduction electric axle system with a modular and adaptable arrangement, featuring a housing, electric motor, planetary gearset systems, synchronizers, helical gears, and a pinion gear, allowing for various gear ratio configurations and improved assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearset systems are added to expand gear range, then gear selectability is improved, but gearbox compactness deteriorates
Solution Approach 1:
The patent combines multiple planetary gearset systems (first and second planetary gearsets) into a single integrated transmission assembly that shares common components such as the sun gear, planet gears, and carrier. This merging approach enables multiple gear ratios to be achieved within a compact volume by having the gearsets share structural elements rather than being separate assemblies.
Solution Approach 2:
The planetary gearset system is designed with multi-functionality where the same physical components (sun gear, planet gears, carrier, annulus gear) serve multiple purposes across different gear ratios. The synchronizers selectively engage different combinations of these universal components to achieve various reduction ratios, allowing one gearset structure to provide multiple gear selection options without requiring separate dedicated gearsets for each ratio.
2Adaptability or versatility
If synchronizers are added to enable gear shifting, then gear selectability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the gear-shifting function into separate synchronizer components that are distinct from the planetary gearset structure itself. The synchronizers are independently mounted and selectively engage with specific gears (sun gear, planet carrier, annulus gear) to enable gear changes, separating the shifting mechanism from the gear transmission mechanism and reducing overall system complexity.
Solution Approach 2:
The synchronizers act as intermediary components between the input shaft and the planetary gearset elements. They mediate the power flow by selectively connecting or disconnecting the input shaft from different gear elements, enabling smooth gear transitions without requiring complex direct engagement mechanisms between the shafts and gears.
3Adaptability or versatility
If more gear reduction stages are added, then speed control range is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the transmission into modular components including the planetary gearset assembly, synchronizer assembly, housing, and differential assembly. Each module can be manufactured and tested independently, then assembled together. The planetary gearset itself is segmented into discrete elements (sun gear, planet gears, carrier, annulus gear) that can be manufactured separately and precision-assembled, facilitating easier manufacturing and quality control.
Solution Approach 2:
The patent incorporates preliminary assembly features such as pre-positioned synchronizers, pre-assembled planetary gear sets with predetermined gear meshing, and pre-configured housing mounting points. These preliminary actions are built into the design to simplify final assembly, reduce assembly errors, and enable faster manufacturing cycles by eliminating complex alignment procedures during final assembly.
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 system achieves compactness, versatility, and ease of assembly while providing a range of speed and reduction capabilities, reducing assembly errors and enhancing structural integrity.
Implementation Method 1
no more than two planetary gearset systems, each planetary gearset system comprising an annulus gear, a sun gear, planet gears, and a planet carrier
Implementation Method 2
no more than two synchronizers wherein each synchronizer is coupled to a respective sun gear and axially moveable to engage the sun gear with one of the at least one cover of the housing or planet carrier
Implementation Method 3
at least two helical gears wherein at least one helical gear is positioned above another helical gear enabling the at least two helical gears to engage with each other
Implementation Method 4
a pinion gear that is coupled to one helical gear via a spline and engages with a ring gear, the ring gear being coupled to a differential
Data Source
AI summary
Systems and methods for a modular multi-speed and multi-reduction electric axle, comprising an electric motor rotationally coupled to a motor shaft, the motor shaft being coupled to an input shaft via splines, no more than two planetary gearset systems that comprise an annulus gear, planet gears, planet carriers, and a cover, no more than two synchronizers that are coupled to a respective sun gear and axially moveable to engage the sun gear with one of a cover or planet carrier of the respective planetary gearset system, at least two helical gears that engage with each other; and a pinion gear that engages with a ring gear, the ring gear being coupled to a differential.