Resin Molded Bushing Elastic Shield Positioning

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Solution Overview

Problem

The existing methods for positioning an electric field relaxation shield within a resin molded bushing in switchgear often result in center deviation and require complex processing and assembly, leading to non-uniform electric field distribution and increased assembly and disassembly work.

Innovation Solution

A resin molded bushing design that incorporates an elastic member, such as a spiral ring, embedded in the cast resin to position the electric field relaxation shield concentrically around the internal conductor, eliminating the need for special mold tool processing and reducing assembly complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If plastic spacers are used to fix the electric field relaxation shield, then the shield can be positioned in the radial direction, but the fixing interval must be elongated when the shield length increases, leading to center deviation

Engineering Contradiction:

Improveease of positioningVSAvoidcoaxiality alignment

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the material parameter from plastic spacer to elastic member (such as coil spring), which fundamentally alters the positioning mechanism from rigid spacing to elastic constraint, enabling the positioning system to adapt to varying shield lengths while maintaining precision

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces dynamic elasticity through the elastic member that can adapt its constraint force based on the shield length and positioning requirements, replacing the static plastic spacer system that requires fixed intervals

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If embedded metal is used to fix the electric field relaxation shield, then positioning can be achieved, but special processing and mounting work must be previously made on the mold tool

Engineering Contradiction:

Improvepositioning accuracyVSAvoidmold tool processing

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts the positioning function from the mold tool structure and transfers it to a separate elastic member that can be independently positioned and installed, eliminating the need for special mold tool processing

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the positioning system into separate components: the elastic member is distinct from both the shield and the mold tool, allowing independent installation and removal without affecting the mold tool structure

Inventive Principle:

Principle #1Segmentation

3Strength

If embedded metal is disposed on the electric field relaxation shield, then fixing can be achieved, but extra work in assembling and disassembling of the mold tool is required

Engineering Contradiction:

Improvefixing strengthVSAvoidassembly and disassembly time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The elastic member is designed to be self-contained and self-sufficient, requiring no additional fasteners, bolts, or external fixing mechanisms that would require assembly and disassembly operations

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The elastic member provides sufficient fixing strength through its elastic properties alone, eliminating the need for additional fixing mechanisms or procedures

Inventive Principle:

Principle #16Partial or excessive action

4Manufacturing precision

If the electric field relaxation shield is fixed by plastic spacer and embedded metal, then positioning can be achieved, but locating more fixing places is difficult

Engineering Contradiction:

Improvepositioning accuracyVSAvoidfixing location flexibility

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The elastic member serves multiple functions: it provides positioning, maintains spacing, and ensures concentricity simultaneously, eliminating the need for multiple separate fixing locations and 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 design prevents center deviation, simplifies assembly, and reduces the time required for mounting, while maintaining effective electric field relaxation without additional processing or disassembly work.

Implementation Method 1

an elastic member which is disposed on the outer periphery of the electric field relaxation shield and is embedded in the cast resin

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2899734B1Resin molded bushing and switch

Publication Date: 2017.06.14 MITSUBISHI ELECTRIC CORP

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AI summary

An object of the present invention is to obtain a resin molded bushing which can easily perform positioning of an electric field relaxation shield in a switchgear. The resin molded bushing includes: an electric field relaxation shield which concentrically surrounds the outer periphery of an internal conductor made of conductor; a cast resin which covers the internal conductor and the electric field relaxation shield; and an elastic member which is disposed on the outer periphery of the electric field relaxation shield and is embedded in the cast resin. The height of the elastic member is equal to the thickness of the cast resin which covers the electric field relaxation shield.