Rotary Electric Machine Terminal Block Insulation and Cooling

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Solution Overview

Problem

Existing rotary electric machines face issues with insulation degradation due to coolant-borne impurities accumulating around connection portions, which can lead to insulation failure over time.

Innovation Solution

The design incorporates a terminal block with partition walls and slits that allow coolant to flow through, preventing impurity accumulation by directing it to the housing, while also accommodating relative expansion differences through orthogonal plate-shaped conductors and curved or bent portions to manage stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If partition walls are added to insulate connection portions, then insulation reliability is improved, but coolant flow is obstructed causing impurity accumulation

Engineering Contradiction:

Improveinsulation reliabilityVSAvoidimpurity accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The terminal block body is divided into multiple insulated chambers by partition walls, with each chamber housing a connection portion. This segmentation provides electrical insulation between phases while the chambers are designed to allow coolant flow through, preventing impurity accumulation around the connection portions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The partition walls are positioned to provide insulation only where needed around connection portions, while maintaining open coolant flow paths through the terminal block. This localized insulation approach ensures electrical isolation without completely blocking coolant circulation, allowing impurities to be flushed away rather than trapped.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If relay conductors are rigidly fixed in terminal block, then connection stability is improved, but thermal expansion stress accumulates

Engineering Contradiction:

Improveconnection stabilityVSAvoidthermal expansion stress

Core Design Contradiction:

Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The relay conductors are designed with flexible portions that allow them to expand and contract in response to thermal changes. This dynamic design enables the conductors to accommodate thermal expansion without generating excessive stress, while maintaining stable electrical connections through the flexible but reliable contact interfaces.

Inventive Principle:

Principle #15Dynamics

3Ease of manufacture

If terminal block structure is simplified, then manufacturing ease is improved, but insulation maintenance over time deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidlong-term insulation maintenance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The terminal block body serves multiple functions simultaneously: it provides structural support for mounting, electrical insulation between phases through partition walls, coolant flow management with integrated channels, and stress accommodation through flexible conductor design. This multi-functionality achieves reliable long-term operation without requiring complex additional components.

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 maintains insulation integrity by preventing impurity accumulation and managing thermal expansion, ensuring long-term insulation and reducing stress on the terminal block.

Implementation Method 1

a plurality of partition walls that extend toward the base wall from the outer wall and insulate peripheral portions of the respective connection portions together with the outer wall

Methodology Applied

Scientific EffectInsulation: Thermal Insulation

Implementation Method 2

when a coolant for cooling the stator enters the terminal block, the flow of the coolant is obstructed by the partition walls

Methodology Applied

Scientific EffectFluid flow: Convection

Implementation Method 3

each of the relay conductors may include a plate-shaped portion that has a constant thickness smaller than the width of the slit, and the plate-shaped portion may be inserted into the slit in a direction orthogonal to a thickness direction

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9136739B2Rotary electric machine

Publication Date: 2015.09.15 HONDA MOTOR CO LTD

AI summary

A rotary electric machine includes a stator around which coil conductor wires for a plurality of phases are wound, a housing that contains the stator, and a terminal block that is mounted on the housing and connects end portions of the coil conductor wires for the respective phases led from the stator to corresponding external power supply lines. A coolant is supplied to the stator in the housing. The terminal block includes: a plurality of relay conductors, each relay conductor having one end connected to an external power supply line and the other end connected to an end portion of the coil conductor wires for 10 the respective phases, and a terminal block body that is made of an insulating material and holds the plurality of relay conductors.