Electric Vehicle Drive Device Radial Space Reduction
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Solution Overview
Problem
Existing drive devices for electric vehicles require significant installation space due to the need for separate housing components between the electric machine and output shaft, which increases the size and complexity of the system.
Innovation Solution
A drive device design where the electric machine and output shaft are arranged parallel to each other within a shared housing cavity, eliminating the need for a radial housing wall between them, thereby reducing the radial installation space and allowing for a more compact gear stage with a higher transmission ratio without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If separate housing components are arranged radially between the electric machine and output shaft, then structural support and component protection are improved, but radial installation space increases
Solution Approach 1:
The patent merges the housing components into a single integrated housing structure that accommodates both the electric machine and output shaft in a shared cavity. The housing forms a unified protective enclosure with bearing supports integrated directly into the housing walls, eliminating the need for separate intermediate housing components and reducing radial space requirements.
Solution Approach 2:
The patent transitions from a radial arrangement with intermediate components to a parallel arrangement where the electric machine and output shaft are positioned side-by-side along the axial direction. This dimensional reconfiguration allows the components to share the same radial space without requiring intermediate housing structures, thereby reducing the overall radial installation footprint.
2Reliability
If intermediate shafts and bearings are included in the drive train, then power transmission reliability is improved, but device complexity and installation space increase
Solution Approach 1:
The patent extracts and eliminates the intermediate shaft from the power transmission path by directly coupling the electric machine rotor shaft to the output shaft through the housing. This removal of the intermediate component simplifies the system architecture while maintaining reliable power transmission through direct mechanical connection and integrated bearing supports.
Solution Approach 2:
The housing serves multiple functions simultaneously: it provides structural support, houses the bearing elements, protects internal components, and facilitates direct power transmission from the electric machine to the output shaft. This multi-functionality eliminates the need for separate intermediate shafts and bearings, reducing complexity while maintaining reliability.
3Ease of manufacture
If the center distance between input axis and output axis is increased, then gear stage dimensions are improved for manufacturing, but radial installation space increases
Solution Approach 1:
The patent changes the geometric parameters of the gear stage by reducing the center distance between the input and output axes through the parallel arrangement configuration. This parameter optimization allows for compact gear dimensions that are easier to manufacture while fitting within a reduced radial installation space, achieving both manufacturing ease and space efficiency.
Data Source
AI summary
A drive device (2) for an at least partially electrically driven vehicle (1) includes an electric machine (3) having a rotor shaft (8) extending longitudinally along an input axis (4). The drive device further includes a first output shaft (6a) extending longitudinally along an output axis (7) and parallel to the rotor shaft (8). Moreover, the drive device includes a gear stage (5) having a first gearwheel (9) rotationally fixed to the rotor shaft (8), and a second gearwheel (10) meshed with the first gearwheel (9) and drivingly connected to the first output shaft (6a). Additionally, the drive device includes a housing (11) having a shared housing cavity (12), wherein the first output shaft (6a) and the electric machine (3) are parallel to one another in the housing cavity (12), and wherein an air gap (18) extends radially between the electric machine (3) and the first output shaft (6a).