Electric Drive Device Compact Design via Propeller Shaft Elimination
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Solution Overview
Problem
Conventional electric drive devices for vehicles, which include a propeller shaft, tend to be large in scale due to weight balance and strength requirements, restricting cabin and trunk space in passenger cars.
Innovation Solution
The electric drive device eliminates the propeller shaft by arranging the rotating machine and retarder on opposite sides of the differential device's axis in a front-rear direction, allowing for a compact design with improved weight balance and reduced dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a propeller shaft is provided in the power transmission path, then the structural strength is improved, but the device size increases and cabin space is restricted
Solution Approach 1:
The patent removes the propeller shaft from the power transmission path by directly connecting the rotating machine to the differential device. This extraction of the unnecessary component eliminates the need for additional reinforcement structures, thereby reducing device size and increasing cabin space while maintaining sufficient structural strength through the direct connection design
Solution Approach 2:
The patent merges the functions of the rotating machine, differential device, and braking device into a more integrated arrangement. By positioning these components adjacent to each other and eliminating intermediate transmission elements like the propeller shaft, the overall device size is reduced while maintaining structural integrity through the combined configuration
2Stability of the object's composition
If the rotating machine and retarder are arranged on opposite sides of the differential device axis, then the weight balance is improved, but the arrangement complexity increases
Solution Approach 1:
The patent employs asymmetric arrangement of components around the differential device axis, with the rotating machine and braking device positioned on opposite sides. This asymmetric configuration achieves optimal weight balance and center of gravity distribution while the overall compact design keeps the arrangement complexity manageable
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 enables a more compact electric drive device with improved weight balance, reducing the need for additional reinforcement and allowing for a smaller footprint, enhancing space efficiency and reducing weight, thus facilitating downsizing.
Implementation Method 1
a retarder provided in a power transmission path between the rotating machine and the differential device and configured to generate a braking force. The retarder is either an electromagnetic retarder or a fluid retarder.
Implementation Method 2
a retarder provided in a power transmission path between the rotating machine and the differential device and configured to generate a braking force. The retarder is either an electromagnetic retarder or a fluid retarder.
Data Source
AI summary
An electric drive device for a vehicle includes: a rotating machine that is used as a driving force source for traveling of the vehicle; a differential device configured to distribute power transmitted from the rotating machine to right and left driving wheels; and a retarder provided in a power transmission path between the rotating machine and the differential device and configured to generate a braking force. The retarder is either an electromagnetic retarder or a fluid retarder. The rotating machine and the retarder are arranged on opposite sides of an axis of the differential device in a front-rear direction of the vehicle in a plan view seen from above the vehicle, the axis of the differential device being parallel to a width direction of the vehicle.