Vehicle Drive Unit Layout With Radial Inverter Packaging
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Solution Overview
Problem
The existing vehicle drive apparatuses with integrated rotary electric machines and inverter devices face space constraints, leading to increased size due to the overlapping of the inverter device with the rotary electric machine, necessitating larger vertical installations.
Innovation Solution
A vehicle drive apparatus design featuring a single-piece case with a partition dividing the housing chambers for the rotary electric machine and inverter device, allowing the inverter device to be housed without expanding the apparatus's size by overlapping it with the output member in a radial direction, thus reducing the overall dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the inverter device is disposed in a region where it overlaps with the rotary electric machine in a vertical view, then the installation region for the inverter device is limited, but this may require increasing the installation space in a vertical direction, resulting in an increase in the size of the vehicle drive apparatus
Solution Approach 1:
The patent transitions from a vertical stacking arrangement to a radial arrangement where the inverter device is positioned in the radial direction relative to the rotary electric machine. This dimensional change allows the inverter device to be installed in the radial space around the rotary electric machine rather than vertically above or below it, effectively utilizing previously unused radial installation region while maintaining a compact overall footprint.
Solution Approach 2:
The inverter device is positioned within the radial envelope of the rotary electric machine, effectively nesting the inverter device in the radial space around the rotary electric machine's stator. This nesting arrangement allows both components to occupy overlapping vertical projections while maintaining separate functional spaces, maximizing space utilization without increasing the overall apparatus size.
2Stability of the object's composition
If a single-piece case is used to house both the rotary electric machine and inverter device, then the case rigidity is enhanced, but the manufacturing complexity and weight may increase
Solution Approach 1:
The single-piece case is segmented into distinct functional regions: a first housing chamber for the rotary electric machine and a second housing chamber for the inverter device. This segmentation is achieved through a partition wall that divides the internal space while maintaining the external integrity of the single-piece case structure. The segmentation allows for optimized component placement and thermal management while preserving the rigidity benefits of a monolithic external structure.
Solution Approach 2:
The single-piece case serves multiple functions simultaneously: it provides structural support and rigidity, acts as a thermal management system with dedicated chambers, provides mechanical protection for both the rotary electric machine and inverter device, and facilitates radial mounting of the inverter device. This multi-functionality reduces the need for additional separate components, thereby managing manufacturing complexity while achieving enhanced rigidity.
3Volume of stationary object
If the inverter device is positioned to overlap with the output member in a radial direction, then the second housing chamber expansion in vertical direction is prevented, but the installation space for the inverter device is constrained
Solution Approach 1:
The inverter device is repositioned from a vertical arrangement to a radial arrangement around the output member. This dimensional change allows the inverter device to utilize the radial space that would otherwise be unused, preventing vertical expansion while providing adequate installation space through the circumferential area available in the radial direction.
Data Source
AI summary
A vehicle drive apparatus includes: a rotary electric machine disposed on a first axis; a differential gear mechanism disposed on a second axis; an output member disposed on the second axis; an inverter device; and a case. The case is a single-piece case internally including: a first housing chamber housing the rotary electric machine; and a second housing chamber housing the inverter device and divided from the first housing chamber with a partition. At least a specified portion of the output member is housed in the first housing chamber. A location of the specified portion in an axial direction overlaps with the rotary electric machine. The partition is provided between the specified portion and the inverter device.