Contact Device with Nested Auxiliary Yoke for Magnetic Efficiency

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Solution Overview

Problem

Conventional contact devices face challenges in reducing power consumption while maintaining magnetic efficiency and minimizing floor area, as increasing the thickness of the auxiliary yoke either leads to magnetic saturation or reduces the winding space.

Innovation Solution

The contact device features a spool wound with a coil between U-shaped yokes, with a movable iron core inserted into the spool's center hole, and an annular auxiliary yoke fitted to the lower surface of the first yoke, reducing magnetic resistance and allowing for a wider winding space, thus achieving a smaller floor area and lower power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the thickness of the auxiliary yoke is increased to reduce magnetic resistance, then magnetic efficiency is improved, but the floor area increases and the device enlarges

Engineering Contradiction:
Improvemagnetic resistanceVSAvoidfloor area
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The auxiliary yoke is nested within the first yoke structure, with the auxiliary yoke's outer circumference fitted into the first yoke. This nesting arrangement allows the auxiliary yoke to reduce magnetic resistance while occupying minimal additional floor area, as it utilizes the existing spatial envelope of the first yoke rather than extending outward.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of increasing the auxiliary yoke thickness in the horizontal plane (which would increase floor area), the invention positions the auxiliary yoke in a vertical or depth dimension within the first yoke's structure. This dimensional repositioning allows the auxiliary yoke to provide its magnetic resistance-reducing function without expanding the device's footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If the thickness of the auxiliary yoke is increased without increasing floor area, then magnetic resistance is reduced, but the winding space cannot be ensured

Engineering Contradiction:
Improvemagnetic resistanceVSAvoidwinding space
Core Design Contradiction:
Loss of energyVSVolume of moving object

Solution Approach 1:

The auxiliary yoke is positioned locally at specific critical positions within the magnetic circuit (fitted to the lower surface of the first yoke) where it provides the most effective magnetic flux path improvement. This localized placement optimizes magnetic resistance reduction while minimizing interference with the coil winding space, as the auxiliary yoke is placed only where most needed rather than uniformly throughout the structure.

Inventive Principle:
Principle #3Local quality

3Area of stationary object

If the thickness of the auxiliary yoke is reduced, then the floor area decreases, but the magnetic resistance becomes large and magnetic saturation easily occurs

Engineering Contradiction:
Improvefloor areaVSAvoidmagnetic resistance
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The auxiliary yoke is nested within the first yoke's structural envelope, allowing it to provide enhanced magnetic flux conduction without increasing the overall device footprint. The auxiliary yoke fits into the existing spatial configuration of the first yoke, maintaining a compact floor area while still providing sufficient thickness to prevent magnetic saturation at critical flux paths.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Loss of energy

If a conventional auxiliary yoke configuration is used, then the magnetic circuit is improved, but the device complexity and assembly difficulty increase

Engineering Contradiction:
Improvemagnetic efficiencyVSAvoidassembly ease
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The auxiliary yoke is designed to be fitted into the first yoke in a nested configuration, creating a integrated assembly where the auxiliary yoke becomes part of the first yoke's structure. This nested design simplifies assembly compared to separate, complex auxiliary yoke arrangements, as the auxiliary yoke can be directly fitted or pressed into the first yoke's designated space, reducing the number of separate assembly steps and fastening operations required.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 configuration enhances magnetic efficiency, reduces power consumption, and ensures a predetermined attractive force while maintaining a compact design, facilitating assembly and productivity.

Implementation Method 1

a movable iron core is inserted to a center hole of the spool in a reciprocating manner, and a contact mechanism unit formed above the second yoke is driven with a drive shaft having a lower end fixed to the movable iron core, which reciprocates based on excitation and demagnetization of the coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an annular auxiliary yoke including an insertion hole communicating to the insertion hole of the first yoke and through which the movable iron core reciprocates is provided at a lower surface of the first yoke

Methodology Applied
Scientific EffectMagnetic resistance reduction: Magnetic Reluctance

Data Source

PatentEP2141724B1Contact device
Publication Date: 2018.12.19 OMRON CORP
  • EP2141724B1 patent drawingFigure 1A~1B
  • EP2141724B1 patent drawingFigure 2
  • EP2141724B1 patent drawingFigure 3

AI summary

This invention provides a contact device having a small floor area and capable of reducing power consumption. A spool wound with a coil is disposed between a first yoke and a second yoke, a movable iron core is inserted to a center hole of the spool in a reciprocating manner, and a contact mechanism unit formed above the second yoke is driven with a drive shaft having a lower end fixed to the movable iron core, and an upper end projecting out from an upper surface of the second yoke. An insertion hole communicating to the center hole of the spool and through which the movable iron core reciprocates is formed in the first yoke. An auxiliary yoke including an insertion hole communicating to the insertion hole of the first yoke and through which the movable iron core reciprocates is provided at a lower surface of the first yoke.