Parallel Twin Gear Electric Drive Module for Compact Packaging
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Solution Overview
Problem
Existing electric drive modules face challenges in compact design due to insufficient space for coaxial arrangements, making it difficult to package them in vehicles, especially in lateral or radial directions.
Innovation Solution
The electric drive module incorporates a transmission with parallel gear pairs that share load to a final drive gear, featuring a drive gear, first and second reduction gears, and a differential assembly, allowing for a compact design by reducing the size of the final drive gear and enabling high-speed operation with low torque, thus accommodating smaller motor assemblies and reducing overall package size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a coaxial arrangement is used for the electric motor, differential assembly and transmission, then the power transmission path is simplified, but the lateral and radial space requirements increase making it difficult to package in vehicles
Solution Approach 1:
The patent transitions from a coaxial arrangement to a parallel axis arrangement, changing the spatial dimension of power transmission. The input shaft and output shaft are positioned parallel to each other rather than coincident, allowing the transmission components to be distributed in a planar configuration that reduces lateral footprint while maintaining functional complexity.
2Force
If a single large final drive gear is used to handle high torque, then the torque capacity is sufficient, but the gear size and overall transmission package size increase
Solution Approach 1:
The patent divides the single large final drive gear into multiple smaller parallel gears (first final drive gear and second final drive gear). These segmented gears share the torque load collectively, allowing each individual gear to be smaller in size while the aggregate system maintains sufficient torque capacity. This segmentation reduces the overall transmission package volume.
Solution Approach 2:
The patent combines multiple parallel gear trains (first gear train with first pinion and first final drive gear, second gear train with second pinion and second final drive gear) to work together in unison. The merged system of multiple smaller gears achieves the torque capacity of a single large gear while occupying less space.
3Area of stationary object
If the transmission uses a compact parallel gear configuration, then the lateral space is reduced, but the gear meshing complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs symmetric replication of gear train components - the first gear train is essentially a mirror image or copy of the second gear train. Both trains have corresponding elements (pinions, final drive gears, reduction gears) that are identical or similar in design. This copying approach simplifies manufacturing by allowing the same gear patterns and specifications to be reused across multiple components, reducing the actual complexity despite the increased number of parts.
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
This configuration allows for a compact and efficient electric drive module that can operate at high rotational speeds with low pitch line velocity, reducing the load on gears and enabling easier packaging within vehicles while using smaller, less expensive motor components.
Implementation Method 1
The first reduction gears are meshingly engaged to the drive gear... Each of the second reduction gears is being meshingly engaged to the driven gear
Implementation Method 2
parallel twin gear pairs sharing load to a final drive gear
Data Source
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AI summary
An electric drive module that includes an electric motor, a differential assembly, and a transmission that transmits rotary power between the electric motor and the differential assembly. The transmission has first and second reductions. The first reduction has a drive gear, which is rotatable about a first axis, and a pair of first reduction gears that are each meshingly engaged to the drive gear rotatable about a respective second axis. The second axes are spaced apart from one another and are parallel to the first axis. The second reduction has a driven gear and a pair of second reduction gears. The driven gear is rotatable about a third axis that is parallel to the first axis. Each of the second reduction gears is being meshingly engaged to the driven gear and non-rotatably coupled to an associated one of the first reduction gears.