Vehicle Drive Layout With Nested Inverter for Reduced Radial Size
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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 position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
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 purely radial arrangement to a three-dimensional configuration where it overlaps the fourth gear in the radial direction while extending axially beyond the rotary electric machine. This dimensional transition allows the inverter device to utilize space in both radial and axial directions, reducing the overall radial dimension of the vehicle drive device while maintaining adequate control functionality.
2Ease of operation
If the fourth gear has a larger diameter than other gears, then the differential gear mechanism functions properly, but the radial space requirement increases
Solution Approach 1:
The inverter device is nested within the radial space occupied by the fourth gear, with part of the inverter device overlapping the fourth gear in the radial direction. This nesting arrangement allows the inverter device to share the radial space with the fourth gear, reducing the overall radial dimension requirement of the vehicle drive device while maintaining the proper function of the differential gear mechanism.
3Length of stationary object
If the inverter device overlaps the fourth gear in the axial direction, then the radial dimension is reduced, but the axial space arrangement becomes more complex
Solution Approach 1:
The inverter device is divided into multiple parts: a first part that overlaps the fourth gear in the radial direction and is disposed within the axial space of the differential gear mechanism, and a second part that extends axially beyond the rotary electric machine. This segmentation allows the inverter device to efficiently utilize both radial and axial spaces, reducing the overall radial dimension while managing axial space complexity through functional zoning.
Data Source
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AI summary
A rotary electric machine (1) is disposed coaxially with an input member (3) and is disposed more toward a first side (L1) in an axial direction than a first gear (32) that meshes with a second gear (42).A third gear (43) that rotates integrally with the second gear (42) and a fourth gear (51) that meshes with the third gear (43) are disposed more toward a second side (L2) in the axial direction than the first gear (32) and the second gear (42).An axis (A2) of a counter gear mechanism (4) is disposed below both an axis (A1) of the rotary electric machine (1) and an axis (A3) of a differential gear mechanism (5).An inverter device (7) is disposed more toward the first side (L1) in the axial direction than the fourth gear (51) and above the axis (A3) of the differential gear mechanism (5) while being disposed at such a position that the inverter device (7) overlaps the fourth gear (51) as seen in the axial direction.A specific portion (P) of the inverter device (7) is disposed between the rotary electric machine (1) and the fourth gear (51) in the axial direction (L), at such a position that the specific portion (P) overlaps the counter gear mechanism (4) as seen in the up-down direction and overlaps the rotary electric machine (1) as seen in the axial direction.