Vehicle Drive Unit Case Structure for Shorter Motor-Differential Spacing
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Solution Overview
Problem
Existing vehicle drive devices face challenges in minimizing the inter-axial distance between the rotary electric machine and the differential gear mechanism, which affects the size and weight of the case, due to interference and structural limitations.
Innovation Solution
The vehicle drive device configuration includes a rotary electric machine with a stator on the outer side of the rotor, an input member connected to the rotor, and a differential gear mechanism arranged on a separate axis, with a case that supports the stator core using an outer peripheral support portion and notch portions to facilitate closer alignment and reduce interference, allowing for a shorter inter-axial distance and reduced case size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the inter-axial distance between the rotary electric machine and differential gear mechanism is reduced, then the case size is reduced, but structural interference and manufacturing complexity increase
Solution Approach 1:
The patent positions the differential gear mechanism axially adjacent to the rotary electric machine, utilizing the axial dimension to reduce the inter-axial distance. This spatial rearrangement allows the differential mechanism to be located near the rotary electric machine's axis, thereby reducing the case size in the radial direction while maintaining functional integrity.
Solution Approach 2:
The case is divided into multiple portions with different numbers of divisions: the first case portion has a different number of divisions than the second case portion. This segmentation allows optimized structural design for each region, reducing overall complexity while accommodating the reduced inter-axial distance configuration.
2Ease of manufacture
If the number of case divisions is reduced, then manufacturing cost is reduced, but structural support and alignment precision may be compromised
Solution Approach 1:
Different case portions have different numbers of divisions tailored to their specific functional requirements. The first case portion has a different division count than the second case portion, allowing each region to be optimized for its specific support and alignment needs while reducing overall manufacturing complexity.
Data Source
AI summary
An input member and a differential gear mechanism include a part arranged on an axial first side with respect to a rotary electric machine. The differential gear mechanism is connected to first wheel via shaft member including part that is arranged on axial second side with respect to differential gear mechanism. A case includes an outer peripheral support portion that is formed along core outer peripheral surface that is an outer peripheral surface of stator core, and that supports core outer peripheral surface in radial direction. A notch portion in which outer peripheral support portion is notched over entire area of arrangement area of stator core in an axial direction is formed in outer peripheral support portion, and notch portion is arranged at position that is between core outer peripheral surface and shaft member in radial direction, and that overlaps shaft member as seen in radial direction along radial direction.