Dual-Contact Relay Layout for Inrush Resistance and Contact Reliability

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Solution Overview

Problem

Existing relays face a trade-off between inrush resistance and contact reliability, with materials like silver-tin-based contacts offering high inrush resistance but poor reliability, and silver-nickel-based contacts providing better reliability but lower melting points, leading to potential welding during high currents.

Innovation Solution

A relay design with separate contact sets using silver-tin-based material for high inrush resistance and silver-nickel-based material for improved reliability, where the contact sets are opened and closed at different timings, with the second contact set closer to the fulcrum for reduced heat generation and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If silver-tin-based material is used for contact, then inrush resistance is improved, but contact reliability deteriorates

Engineering Contradiction:
Improveinrush resistanceVSAvoidcontact reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The contact part is divided into two separate contact sets: a first contact set using silver-tin-based material for high inrush resistance, and a second contact set using silver-nickel-based material for high contact reliability. This segmentation allows each material to be optimized for its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different materials are assigned to different contact sets based on their specific functional requirements. The silver-tin-based material is locally applied to the first contact set where inrush resistance is critical, while silver-nickel-based material is applied to the second contact set where contact reliability is paramount.

Inventive Principle:
Principle #3Local quality

2Reliability

If silver-nickel-based material is used for contact, then contact reliability is improved, but inrush resistance deteriorates

Engineering Contradiction:
Improvecontact reliabilityVSAvoidinrush resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The contact part is divided into two separate contact sets: a first contact set using silver-tin-based material for high inrush resistance, and a second contact set using silver-nickel-based material for high contact reliability. This segmentation allows each material to be optimized for its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different materials are assigned to different contact sets based on their specific functional requirements. The silver-tin-based material is locally applied to the first contact set where inrush resistance is critical, while silver-nickel-based material is applied to the second contact set where contact reliability is paramount.

Inventive Principle:
Principle #3Local quality

3Reliability

If the direction of roll marks on movable terminal is changed, then contact reliability may be improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvecontact reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of changing the roll mark direction of the entire movable terminal, the invention segments the contact function into two separate contact sets with different materials, allowing the original roll mark configuration to be maintained while achieving improved overall reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable terminal uses composite material construction with silver-tin-based material for the first contact set and silver-nickel-based material for the second contact set, combining the advantages of both materials without requiring changes to the roll mark configuration.

Inventive Principle:
Principle #40Composite materials

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 design achieves enhanced inrush resistance and contact reliability by utilizing optimal materials for each contact set, reducing heat generation and extending relay life through separate contact operations.

Implementation Method 1

a movable contact spring member having an intermediate portion; a first movable contact provided at a first end of the movable contact spring member; a second movable contact provided at the intermediate portion

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a contact made of a material having a relatively high melting point and high hardness is used

Methodology Applied
Scientific EffectThermal resistance: Thermal Insulation

Implementation Method 3

a contact made of a material having a relatively low melting point and low hardness is often used

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4668309A1relay
Publication Date: 2025.12.24 FCL COMPONENTS LTD
  • EP4668309A1 patent drawingFigure 1
  • EP4668309A1 patent drawingFigure 2
  • EP4668309A1 patent drawingFigure 3

AI summary

A relay having high inrush resistance and energization/contact reliability is provided. The relay comprising an electromagnet, a base part at which the electromagnet is positioned, a fixed contact member fixed to the base part, and a movable contact spring supported by the base part and configured to elastically deformed by an operation of the electromagnet. The fixed contact member has a first fixed contact and a second fixed contact. The movable contact spring has a first movable contact opposed to the first fixed contact and a second movable contact opposed to the second fixed contact. A distance along a shape of the movable contact spring from a portion which serves as a fulcrum for elastic deformation of the movable contact spring, to the first movable contact, is longer than a distance along the shape of the movable contact spring from the portion to the second movable contact.