Insulating Film Segmentation for Temperature-Dependent Switch Sealing

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Solution Overview

Problem

Existing temperature-dependent switches face issues with thermal connection complexity and leakage due to the waviness of insulating films when bent, allowing liquids and paint to penetrate the housing, compromising the seal and electrical insulation.

Innovation Solution

The insulating film is modified with radially extending slots in its edge region, allowing it to lie flat and reduce counter-pressure, ensuring a secure seal and preventing liquid ingress, with preferred distribution and design of slots for optimal sealing and dielectric strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the insulating film is bent over the cover part to provide electrical insulation, then electrical insulation between lower part and cover part is improved, but the insulating film becomes wavy and allows liquid penetration

Engineering Contradiction:
Improveelectrical insulationVSAvoidliquid penetration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The insulating film is segmented by providing radially extending slots in its edge region, which divides the film into multiple sections. This segmentation allows the film to lie flat against the cover part without waviness, while maintaining electrical insulation between the lower part and cover part, and preventing liquid penetration through the housing.

Inventive Principle:
Principle #1Segmentation

2Strength

If the wall of lower part is bent over to hold cover part firmly, then mechanical seal is improved, but insulating film counter-pressure increases causing waviness

Engineering Contradiction:
Improvemechanical sealVSAvoidinsulating film counter-pressure
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

By segmenting the insulating film through radially extending slots, the counter-pressure from the bent wall is distributed across multiple sections rather than concentrating on a continuous film. This reduces the overall waviness and allows the mechanical seal to remain strong while minimizing film deformation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The slots are strategically positioned in the edge region of the insulating film, creating local variations in film structure. This allows the film to have different properties in different regions - more flexible at the slots to accommodate bending, and intact in other areas to maintain insulation and sealing.

Inventive Principle:
Principle #3Local quality

3Reliability

If insulating film edge area extends to top of cover part, then electrical insulation is improved, but liquid creepage paths are created on peripheral end face

Engineering Contradiction:
Improveelectrical insulationVSAvoidliquid creepage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The radially extending slots segment the insulating film's edge area, which eliminates continuous liquid creepage paths along the peripheral end face. The slots create discontinuities that prevent liquid from creeping along the film edge, while the film still extends to the top of the cover part to provide adequate electrical insulation.

Inventive Principle:
Principle #1Segmentation

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

The solution provides a structurally simple and cost-effective enhancement to the switch, ensuring a reliable mechanical seal and electrical insulation, preventing paint and liquid penetration while maintaining excellent dielectric strength.

Implementation Method 1

a bimetallic disc slipped over the moving contact part... the bimetallic disc changes its configuration and works against the spring snap-in disc in such a way that it separates the movable contact part from the stationary counter-contact

Methodology Applied
Scientific EffectBimetallic effect: Bi-Metallic Strip

Implementation Method 2

The spring snap-action disc presses the movable contact part against a stationary mating contact inside the cover part

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

The insulating film has at least two radially extending slots in its edge region... ensuring a secure seal and preventing liquid ingress

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2775495B1Temperature-dependent switch with insulating disc
Publication Date: 2015.07.22 HOFSAESS MARCEL P
  • EP2775495B1 patent drawingFigure 1
  • EP2775495B1 patent drawingFigure 2
  • EP2775495B1 patent drawingFigure 3

AI summary

The switch (10) has an insulating film (15) arranged between a lower portion (12) and a cover portion (16). An edge area (21) of the film is bent to a top (18) of the cover portion and a wall (22) of the lower portion on the top, to hold the cover portion under an intermediate layer of the insulating film on the lower portion. A temperature-dependent switching mechanism (24) is arranged in a housing (11), to open two conductive connection between contact surfaces (32, 33) in outside of the housing. Two radially extending slits are provided in the edge region of the insulating film.