Vehicle Drive Unit Layout for Compact Radial Packaging
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Solution Overview
Problem
The existing vehicle drive devices face challenges in minimizing their radial dimension due to the large diameter of the inverter device and differential gear components, making it difficult to fit them in spaces with limited radial margin, such as under the vehicle floor.
Innovation Solution
The configuration includes a rotary electric machine disposed coaxially with the input member, with the inverter device positioned to overlap the differential gear mechanism, and specific portions of the inverter device placed between the rotary electric machine and the differential gear, allowing for a more compact arrangement by utilizing the space created by the counter gear mechanism's lower positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inverter device is disposed above the differential gear mechanism and the fourth gear has a larger radial dimension, then the control function is achieved, but the radial dimension of the vehicle drive device increases
Solution Approach 1:
The inverter device is repositioned from a vertical arrangement (above the differential gear mechanism) to a horizontal arrangement (radially inside the fourth gear). This dimensional change allows the inverter device to occupy radial space rather than axial space, thereby reducing the overall radial dimension of the vehicle drive device while maintaining the control function.
Solution Approach 2:
The inverter device is nested within the radial space of the fourth gear, utilizing the internal space of the larger component. This nesting arrangement allows the inverter device to be housed within the radial envelope of the differential gear mechanism, effectively reducing the external radial dimension of the entire assembly.
2Reliability
If the fourth gear has a larger radial dimension than the first and second gears, then the differential function is achieved, but the device becomes difficult to dispose in spaces with small radial margin
Solution Approach 1:
The arrangement of gears is optimized by positioning the larger fourth gear such that its radial space is efficiently utilized. The inverter device is placed within this radial space, converting the fourth gear's larger radial dimension from a space-consuming feature into a space-providing feature that accommodates the inverter device, thereby improving space adaptability.
Solution Approach 2:
The fourth gear serves dual functions: it performs the differential function by meshing with the third gear and distributing rotation, and simultaneously provides radial space for housing the inverter device. This multi-functionality allows the larger radial dimension of the fourth gear to benefit both the differential operation and the compact integration of the inverter device.
Data Source
AI summary
A rotary electric machine is disposed coaxially with an input member more toward a first side in an axial direction than a first gear that meshes with a second gear. A third gear rotates integrally with second and fourth gears that mesh with third gear more toward second side in axial direction than first and second gears. An axis of a counter gear mechanism is below axis of rotary electric machine and axis of differential gear mechanism. An inverter device more toward first side in axial direction than fourth gear and above axis of differential gear mechanism while that inverter device overlaps fourth gear as seen in axial direction. A specific portion of inverter device is between rotary electric machine and fourth gear in axial direction, such hat specific portion overlaps counter gear mechanism as seen in up-down direction and overlaps rotary electric machine as seen in axial direction.