Integrated Rotating Electrical Machine Molded Modules

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Solution Overview

Problem

The existing drive unit integrated rotating electrical machines face issues with poor productivity, thermal resistance, and vibration resistance due to the use of ceramic boards and bare chip mounting of semiconductor switching elements, which lead to cracking and detachment from heat sinks.

Innovation Solution

The solution integrates power switching elements and conductors into mold modules with exposed terminals, which are insert-molded into a frame and firmly fixed to a heat sink, eliminating the need for ceramic boards and improving connection and vibration resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ceramic board and bare chip mounting are used, then semiconductor switching elements can be mounted, but productivity is poor

Engineering Contradiction:
Improveassembly productivityVSAvoidmounting complexity
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent combines the ceramic board, semiconductor switching elements, and connection terminals into an integrated molded module. The molding process simultaneously encapsulates the semiconductor elements and forms the connection terminals, eliminating separate mounting steps and significantly improving productivity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The semiconductor switching elements and connection terminals are pre-assembled and encapsulated in a molded state before being installed on the heat sink. This preliminary assembly and encapsulation simplifies the final installation process and improves manufacturing efficiency.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If ceramic board is soldered to heat sink, then electrical connection is achieved, but cracking occurs over temperature cycles increasing thermal resistance

Engineering Contradiction:
Improvethermal connection reliabilityVSAvoidthermal resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the connection method from soldering to a molded mechanical-electrical connection. The molding material creates a robust connection between the module and heat sink that is resistant to thermal cycling, preventing cracking and maintaining low thermal resistance over temperature variations.

Inventive Principle:
Principle #35Parameter changes

3Strength

If ceramic board is fixed to heat sink by soldering, then thermal conduction is achieved, but the ceramic board comes off due to environmentally-induced vibrations

Engineering Contradiction:
Improvevibration resistanceVSAvoidattachment reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent uses a composite molded structure that integrates the ceramic board, semiconductor elements, and connection terminals into a single robust unit. The molding material provides mechanical strength and vibration resistance, creating a reliable attachment to the heat sink that withstands environmental vibrations.

Inventive Principle:
Principle #40Composite materials

4Ease of operation

If bare chip mounting is used, then semiconductor elements can be connected, but connection between mold modules and frame is difficult

Engineering Contradiction:
Improveconnection easeVSAvoidconnection complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the semiconductor switching elements and connection terminals into an integrated molded module. The terminals are exposed and pre-positioned, making connection to the frame straightforward and reducing operational complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 simplifies connections, enhances vibration resistance, and improves heat transfer and productivity by allowing easier assembly and more reliable attachment of mold modules to the heat sink, reducing thermal resistance and increasing the machine's operational efficiency.

Implementation Method 1

a heat sink cooling the drive unit

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP2713484B1Driving-apparatus integrated type rotating electrical machine
Publication Date: 2017.05.03 MITSUBISHI ELECTRIC CORP
  • EP2713484B1 patent drawingFigure 1
  • EP2713484B1 patent drawingFigure 2
  • EP2713484B1 patent drawingFigure 3

AI summary

Problem To obtain a drive unit integrated rotating electrical machine that makes it easier to connect power circuits and achieves not only excellent vibration resistance but also excellent heat releasing properties. Means for Solution A drive unit integrated rotating electrical machine has a motor, a drive unit driving the motor under control and provided with power switching elements and conductors passing a current to the power switching elements, and a heat sink cooling the drive unit, which are combined into one unit. The drive unit integrated rotating electrical machine is characterized in that: the power switching elements are molded and formed into mold modules in a state in which terminals thereof are exposed; the conductors are insert-molded in a frame in a state in which terminals thereof are exposed; and the exposed terminals of the mold modules are connected to the exposed terminals of the insert-molded conductors and the mold modules are firmly fixed to the heat sink.