Multi-Part Bushing Assembly for Sealed Housing Replacement

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Solution Overview

Problem

Existing bushing designs for electrical equipment, such as capacitors, do not allow for easy replacement of damaged bushing members after the capacitor unit is sealed, as the inner nut is inaccessible once the lid is welded, leading to the need for replacing the entire unit.

Innovation Solution

A bushing assembly comprising multiple first bushing members with radial protrusions to prevent movement through openings and a second bushing member for secure attachment, allowing for releasable connection without exposing the second bushing member outside the housing, enabling replacement without disassembling the sealed unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the lid is welded onto the rest of the capacitor housing, then the capacitor unit is sealed and protected, but the inner nut becomes inaccessible and the outer bushing member cannot be replaced

Engineering Contradiction:
Improvesealing integrityVSAvoidbushing replacement accessibility
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The bushing assembly is divided into multiple independent components: an outer bushing member, an inner bushing member, and a retention member. This segmentation allows the outer bushing to be replaced by accessing only the retention member through the sealed housing, without needing to open the lid or access the inner bushing member directly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bushing assembly uses a nested structure where the inner bushing member is positioned within the outer bushing member, and the retention member secures the inner bushing. This nested arrangement allows the retention member to be accessed from the outside through the sealed housing while still providing secure attachment of both bushing members.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Strength

If the outer bushing member is secured by screwing the inner bushing member onto a threaded portion, then the bushing is firmly attached, but the entire unit must be replaced if the outer bushing is damaged after sealing

Engineering Contradiction:
Improvebushing attachment strengthVSAvoidcomponent replaceability
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The attachment mechanism is segmented into a retention member that threads onto the inner bushing member and engages with the outer bushing member. This segmentation allows the outer bushing to be independently replaced by manipulating only the retention member through the sealed housing opening, while the inner bushing member and threaded connection remain intact.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retention member acts as an intermediary component between the inner and outer bushing members. It provides the threaded connection point that can be accessed from outside the sealed housing, allowing the outer bushing to be secured or replaced without direct access to the inner bushing or the threaded portion itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the second bushing member is positioned inside the sealed housing, then it is protected from damage, but it cannot be accessed for manual securing during assembly

Engineering Contradiction:
Improveprotection from damageVSAvoidassembly accessibility
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The bushing assembly is segmented so that the retention member can be manipulated through the sealed housing opening to secure the second bushing member from the outside. This allows the second bushing member to remain positioned inside the sealed housing for protection while still being accessible for assembly operations through the opening.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retention member serves as an intermediary that translates external manipulation into internal securing action. It can be inserted through the sealed housing opening, engaged with the inner bushing member, and used to secure the outer bushing member, all without requiring direct access to the second bushing member inside the housing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4254436A1Bushing assembly for a housing for electrical
Publication Date: 2023.10.04 HITACHI ENERGY LTD
  • EP4254436A1 patent drawingFigure 1~3
  • EP4254436A1 patent drawingFigure 4~7
  • EP4254436A1 patent drawingFigure 8

AI summary

A bushing assembly (1) for mounting in openings (2) of a panel (3) of a housing (4) for electrical equipment, such as a capacitor housing. The bushing assembly (1) comprises a plurality of first bushing members (5) releasably attachable through a respective one of said openings (2) of the panel (3) to a single second bushing member (11) positioned on an inside of the panel inside the housing (4).