Vehicle Drive Inverter Layout for Compact Dual-Motor Packaging

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Solution Overview

Problem

Existing vehicle drive devices face challenges in compactly mounting inverters due to surplus space and component arrangements that expand the height dimension, particularly with components like capacitors and semiconductor modules.

Innovation Solution

The vehicle drive device incorporates a layout where the inverter is arranged over the left and right motors and gearbox, with a capacitor and semiconductor module suspended on a cover, and a gearbox offset to create a depressed portion for efficient space utilization, eliminating the need for a base plate and allowing components to be positioned without overlapping the rotating shafts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the inverter is installed on a partitioning wall that partitions the accommodating space, then the inverter can be mounted in a structured manner, but there is likely to be a surplus space above the inverter which requires improvement for the compactness

Engineering Contradiction:
Improvemounting structureVSAvoidcompactness
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The inverter is mounted on the ceiling surface (top surface) of the accommodating space rather than on a vertical partitioning wall. This dimensional change from vertical to horizontal mounting utilizes the previously wasted vertical space above the inverter, thereby improving compactness while maintaining ease of manufacture through a simplified mounting structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the components of an inverter are arranged by overlaying in the up-down direction, then the inverter can be structured, but the height dimension of the inverter is expanded

Engineering Contradiction:
Improvecomponent arrangementVSAvoidheight dimension
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The capacitor and semiconductor module are arranged in the left-right direction (horizontal plane) rather than overlaying in the up-down direction. This dimensional rearrangement reduces the height dimension of the inverter while maintaining ease of manufacture through a planar layout that simplifies assembly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The semiconductor module is specifically positioned at a location displaced from the rotating shafts when viewed from above, creating a localized arrangement that optimizes space utilization. This local positioning quality allows for reduced height while maintaining functional requirements and ease of assembly.

Inventive Principle:
Principle #3Local quality

3Power

If the gearbox is positioned centrally between the motors, then the torque transmission is optimized, but the space utilization above the motors is reduced

Engineering Contradiction:
Improvetorque transmissionVSAvoidmounting space
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The inverter is mounted on the ceiling surface of the accommodating space, utilizing the vertical space above the motors and gearbox. This dimensional utilization of previously wasted space allows the gearbox to remain centrally positioned for optimized torque transmission while increasing the overall mounting space availability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This layout enables a compact design by effectively using space, reducing the vertical dimension of the inverter, simplifying assembly, and enhancing cost efficiency while maintaining cooling performance.

Implementation Method 1

an inverter that is arranged in a mounting space over the left and right motors and the gearbox and that includes a capacitor smoothing electric power

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4412073B1Vehicle drive device
Publication Date: 2025.11.26 MITSUBISHI MOTORS CORP
  • EP4412073B1 patent drawingFigure 1
  • EP4412073B1 patent drawingFigure 2
  • EP4412073B1 patent drawingFigure 3

AI summary

The disclosed vehicle drive device (10) includes: left and right motors (1,2) that drive left and right wheels of the vehicle; a gearbox (3) that is sandwiched between the left and right motors (1,2); and an inverter (4) that is arranged in a mounting space (S) over the left and right motors (1,2) and the gearbox (3). The gearbox (3) forms, in conjunction with respective motor housings (11,12) of the left and right motors (1,2), a depressed portion (8) depressed downward. The inverter (4) includes a cover (15) that is in a flat-plate shape, is attached to a tray unit (16), and covers the capacitor (5) and a semiconductor module (6) from above the capacitor (5) and the semiconductor module (6). The capacitor (5) is attached to a lower surface of the cover (15) and is arranged in the depressed portion (8). The semiconductor module (6) is attached to the lower surface of the cover (15) and is displaced from each of the capacitor (5) and the rotating shafts (C) of the motors (1,2) when seen from above.