Vehicle Drive Unit Cooling Layout for Motor and Inverter

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing vehicle driving devices face challenges in effectively cooling both the rotary electrical machine and the inverter module, leading to insufficient cooling of the rotary electrical machine.

Innovation Solution

The vehicle driving device incorporates a case with a first accommodating chamber for the rotary electrical machine, a second accommodating chamber for the inverter module, and a division wall. An oil storage portion is located in the lower portion of the first chamber, and a first water passage for cooling the inverter module connects to a second water passage facing the lower surface of the rotary electrical machine, allowing cooling water to efficiently cool both components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single water passage is used to cool the inverter module, then the structure is simple, but both the inverter module and rotary electrical machine cannot be appropriately cooled simultaneously

Engineering Contradiction:
Improvecooling system structureVSAvoidcomponent cooling effectiveness
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The cooling system is segmented into two distinct water passages within the case: the first water passage positioned to cool the inverter module, and the second water passage positioned to cool the rotary electrical machine through the oil. This segmentation increases cooling effectiveness for both components while maintaining a relatively simple integrated case structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The case structure serves multiple functions: it accommodates both the inverter module and rotary electrical machine, stores oil for cooling the rotary electrical machine, and incorporates both water passages to provide dual cooling paths. This multi-functionality allows effective cooling of both components without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration ensures that the inverter module is appropriately cooled by the first water passage, the oil stored in the oil storage portion is cooled by the second water passage, and ultimately, the rotary electrical machine is effectively cooled, addressing the issue of insufficient cooling in existing devices.

Implementation Method 1

a first water passage through which cooling water for cooling the inverter module (40) flows is provided in the second accommodating chamber (A2) or the division wall (58)

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

cooling water for cooling the inverter module (40) flows is provided in the second accommodating chamber (A2) or the division wall (58)

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

a second water passage (66) connected to the first water passage (61) is provided in a region facing a lower surface of the rotary electrical machine (10) in the case (50)

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

the oil stored in the oil storage portion can be cooled by the cooling water flowing from the first water passage (61) to the second water passage (66)

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 5

ultimately the rotary electrical machine can be appropriately cooled

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP4530106A1Vehicle driving device
Publication Date: 2025.04.02 AISIN CORP
  • EP4530106A1 patent drawingFigure 1
  • EP4530106A1 patent drawingFigure 2
  • EP4530106A1 patent drawingFigure 3

AI summary

A vehicle driving device (1) includes: a rotary electrical machine (10); an output member (30) configured to be drivingly coupled to a wheel (W); a power transmission mechanism (20) configured to transmit a driving force between the rotary electrical machine and the output member; an inverter module (40) configured to control driving of the rotary electrical machine; and a case (50) configured to accommodate the rotary electrical machine, the power transmission mechanism, and the inverter module. The case includes a first accommodating chamber (A1) in which the rotary electrical machine is accommodated, a second accommodating chamber (A2) in which the inverter module is accommodated, and a division wall (58, 52B) dividing the first accommodating chamber and the second accommodating chamber. An oil storage portion (R1) configured to store oil is formed in a lower portion of the first accommodating chamber. A first water passage (61) through which cooling water for cooling the inverter module flows is provided in the second accommodating chamber or the division wall. A second water passage (66) connected to the first water passage is provided in a region facing a lower surface of the rotary electrical machine in the case.