Electric Fuse Device With Bent Wire Tripping Mechanism

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Solution Overview

Problem

Conventional electrical safety devices for motor vehicles face challenges in achieving a defined and reproducible tripping characteristic due to difficulties in applying and positioning low-melting metal bodies, leading to fluctuations in triggering behavior.

Innovation Solution

An electrical safety device featuring a bent wire made of low-melting metal, inserted through openings in an electrically insulating carrier, which melts and breaks when overloaded, providing precise control over tripping characteristics by varying wire dimensions and configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a metal body is melted onto the conductor tracks to bridge the gap, then the fuse can be manufactured, but the tripping characteristics show significant fluctuations due to inconsistent size, shape, and positioning of the metal body

Engineering Contradiction:
Improvetripping characteristic reproducibilityVSAvoidmetal body application consistency
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention changes the geometric parameters of the fusible element from an irregular metal body to a wire with controlled diameter (0.2-1.0 mm) and length (5-20 mm). This parameter standardization ensures consistent tripping characteristics while maintaining ease of manufacture through simple insertion into pre-drilled holes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The wire is pre-formed with specific dimensions and inserted into pre-drilled holes in the carrier before the conductor tracks are applied. This preliminary positioning ensures consistent location and orientation, eliminating positioning variations that would affect tripping characteristics.

Inventive Principle:
Principle #10Preliminary action

2Speed

If the wire diameter is decreased to reduce heat capacity for faster tripping, then the response time improves, but the wire becomes more fragile and harder to handle during manufacturing

Engineering Contradiction:
Improvetripping response timeVSAvoidwire handling difficulty
Core Design Contradiction:
SpeedVSEase of manufacture

Solution Approach 1:

The invention defines an optimal parameter range for wire diameter (0.2-1.0 mm) and length (5-20 mm) that balances thermal response speed with mechanical handleability. Wires within this range have sufficient heat capacity for reliable manufacturing handling but low enough thermal mass to trip quickly under overload conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The wire dimensions can be dynamically adjusted within the specified ranges to match different application requirements. Thinner, shorter wires provide faster tripping for sensitive applications, while thicker, longer wires offer more handling margin for robust manufacturing processes.

Inventive Principle:
Principle #15Dynamics

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 ensures a reliable and reproducible tripping mechanism with minimal production-related fluctuations, allowing for precise setting of current levels and response times, while maintaining a compact design and easy manufacturing.

Implementation Method 1

If the bent wire heats up above its melting point as a result of an overload, the wire begins to melt

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The molten metal collects in a droplet, which falls from the wire due to gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3420575B1Electric fuse device
Publication Date: 2020.08.12 LISA DRAXLMAIER GMBH
  • EP3420575B1 patent drawingFigure 1~3
  • EP3420575B1 patent drawingFigure 4~5
  • EP3420575B1 patent drawingFigure 6~7b

AI summary

The invention relates to an electric fuse device (1) and a method for producing same. The fuse device comprises: at least one electrically insulating carrier (2); a first conductor track (3) and a second conductor track (4), which are mounted on the carrier (2) and are mutually spaced and electrically insulated from one another by a gap (5); a first through-passage (6) through the carrier (2) and the first conductor track (3) and a second through-passage (7) through the carrier (2) and the second conductor track (4), the gap (5) being bridged by a bent wire (8) consisting of a low-melting metal pushed through the through-passages (6, 7) from one side of the carrier (2) and fused onto the other side of said carrier (2).