Power Conversion Device Annular Seal Water Infiltration

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Solution Overview

Problem

Existing power conversion devices, such as those in electric vehicles and hybrid cars, face watertightness issues due to water infiltration at the interface between grommets and the housing, leading to potential corrosion and compromised sealing during exposure to water, such as during car washes.

Innovation Solution

A power conversion device design featuring an annular seal member with a flange portion and an annular groove to prevent water from reaching the interface between the protruding pipes and the housing, ensuring effective sealing and preventing corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If grommets are used to seal the interface between the refrigerant pipes and the housing, then the sealing function is provided, but water infiltration and corrosion occur at the grommet-housing interface

Engineering Contradiction:

Improvesealing functionVSAvoidwater infiltration and corrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an annular seal member as an intermediary component between the refrigerant pipe and the housing. This seal member includes a seal body portion that contacts both the pipe and housing, and a flange portion that extends radially outward to contact the housing outer surface, creating an additional sealing interface that prevents water infiltration at the grommet-housing interface.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent adds a radial dimension to the sealing structure by extending the flange portion of the seal member radially outward from the seal body. This creates a multi-dimensional sealing approach where sealing occurs both axially (at the pipe-housing interface) and radially (at the flange-housing interface), preventing water infiltration from multiple directions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the housing is exposed to water during car washes or rainfall, then the device operates in normal conditions, but water accumulates at the interface causing corrosion

Engineering Contradiction:

Improveoperation under wet conditionsVSAvoidwater accumulation and corrosion

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by providing the annular seal member with flange portion before water infiltration occurs. The flange portion protruding from the housing outer surface creates a preventive barrier that stops water from reaching and accumulating at the critical pipe-housing interface, thereby preventing corrosion before it can occur.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the potential harm of water exposure into a benefit by designing the flange portion to actively redirect water flow away from the housing interface. The flange structure transforms the harmful water infiltration into a controlled flow path that protects rather than damages the housing and pipe connection.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11252845B2Power conversion device

Publication Date: 2022.02.15 DENSO CORP

AI summary

A power conversion device includes an electronic component, a cooler, a housing, protruding pipes, and annular seal members. Each of the seal members includes a seal body portion interposed between a corresponding one of the protruding pipes and the housing, and a flange portion extending outward from the seal body portion in a radial direction and contacting an outer surface of the housing from an axial direction. The housing includes a peripheral wall surface formed to surround the flange portion from an outer peripheral side, and an annular groove portion formed along an outer peripheral edge of the flange portion inside the peripheral wall surface. The peripheral wall surface is formed to extend outward, in the axial direction, from an axial contact surface of the housing contacted by the flange portion.