Vehicle Drive Layout for Larger Smoothing Capacitors

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Solution Overview

Problem

The related art structure limits the size of the smoothing capacitor due to its overlap with the power switching element in the axial direction, preventing an increase in size without increasing the axial size of the vehicle drive device.

Innovation Solution

The smoothing capacitor is positioned radially outer to the power switching element when viewed in the axial direction, with the cover member supporting both and integrating the motor drive device, reducing the axial size by eliminating the need for a separate cover and minimizing the axial distance between components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the power switching element and smoothing capacitor are disposed to overlap each other in the axial direction, then the axial size of the vehicle drive device is reduced, but the size of the smoothing capacitor cannot be increased

Engineering Contradiction:

Improvesize of smoothing capacitorVSAvoidaxial size of vehicle drive device

Core Design Contradiction:

Volume of moving objectVSLength of moving object

Solution Approach 1:

The patent transitions from axial stacking (one-dimensional arrangement) to radial placement (two-dimensional arrangement). The smoothing capacitor is positioned on the radially outer side of the power switching element, utilizing the radial dimension instead of the axial dimension. This allows the capacitor to be enlarged without increasing the axial length of the device, effectively resolving the contradiction between capacitor size and axial compactness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If a separate cover member is used to support the power switching element and smoothing capacitor, then the components can be properly supported, but the axial size increases

Engineering Contradiction:

Improveassembly easeVSAvoidaxial size

Core Design Contradiction:

Ease of operationVSLength of moving object

Solution Approach 1:

The patent merges the cover member with the housing member by integrating the power switching element support structure directly into the housing. The housing member now performs dual functions: supporting the rotary electric machine and supporting the power switching element. This eliminates the need for a separate cover member, reducing the axial size while maintaining proper component support and assembly ease.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The housing member is designed to serve multiple functions: it houses the rotary electric machine, supports the power switching element, and provides structural support for the overall assembly. This multi-functional design eliminates the need for additional dedicated support structures, thereby reducing axial dimension while maintaining structural integrity and ease of assembly.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12556062B2Vehicle drive device

Publication Date: 2026.02.17 AISIN CORP

AI summary

A vehicle drive device includes: a rotary electric machine including a rotor and a stator; a housing member forming a housing chamber that houses the rotary electric machine; a cover member connected to one end side of the housing member in an axial direction, facing the rotary electric machine in the axial direction, and including a bearing support portion that rotatably supports the rotor; a power switching element electrically connected to a coil of the stator; and a smoothing capacitor electrically connected to the power switching element. The smoothing capacitor is disposed on a radially outer side of the power switching element when viewed in the axial direction.