Solenoid With Separate Magnetic Paths For Reliable Release

Solution Overview

Problem

In solenoids with both permanent magnets and coils, the release operation is incomplete due to the magnetic flux generated by the coil counteracting the magnet's flux, leading to an unreliable decrease in attraction force when the coil's magnetic flux exceeds the magnet's.

Innovation Solution

A solenoid design where a permanent magnet and coil are housed in a cylindrical case with a ring member and a metallic coil cover, ensuring separate magnetic paths for the magnet's and coil's flux, preventing the attraction portion from being in the middle of these paths, and maintaining a specific distance between the case's inner wall and the ring member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coil generates sufficient magnetic flux to counteract the permanent magnet's flux for complete release operation, then the release operation becomes complete, but the magnetic flux passing through the attraction portion is switched back to the coil's magnetic flux and attraction force is generated again

Engineering Contradiction:

Improverelease operation completenessVSAvoidattraction force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent divides the magnetic flux paths into separate segments: one path for the permanent magnet's flux and another path for the coil's flux. This is achieved by positioning the attraction portion (where the movable iron core contacts the ring member) outside the middle of both magnetic paths, ensuring that the two flux paths do not overlap or interfere with each other at the attraction portion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a metallic coil cover as an intermediary component that covers the entire coil. This coil cover acts as a magnetic shield or mediator that directs the coil's magnetic flux through a specific path that does not pass through the attraction portion, thereby preventing the coil's flux from generating unwanted attraction force at the contact point between the movable iron core and ring member.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the coil's magnetic flux is increased to ensure complete release operation, then the release operation is reliable, but the attraction force cannot be reliably decreased when the coil's flux exceeds the magnet's flux

Engineering Contradiction:

Improverelease operation reliabilityVSAvoidattraction force control

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent divides the magnetic flux paths into separate segments: one path for the permanent magnet's flux and another path for the coil's flux. This is achieved by positioning the attraction portion (where the movable iron core contacts the ring member) outside the middle of both magnetic paths, ensuring that the two flux paths do not overlap or interfere with each other at the attraction portion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a metallic coil cover as an intermediary component that covers the entire coil. This coil cover acts as a magnetic shield or mediator that directs the coil's magnetic flux through a specific path that does not pass through the attraction portion, thereby preventing the coil's flux from generating unwanted attraction force at the contact point between the movable iron core and ring member.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 allows for a reliable quick release operation by suppressing the increase in magnetic flux through the attraction portion, effectively reducing the attraction force of the movable iron core even when the coil's flux exceeds the magnet's.

Implementation Method 1

magnetic flux generated by the permanent magnet passes through a portion (attraction portion) where a movable iron core and another part are attracted to each other, so that attraction force is generated

Methodology Applied

Scientific EffectMagnetic flux generation: Magnetism

Implementation Method 2

When the coil is energized, magnetic flux generated by the coil flows so as to counteract the magnetic flux generated by the magnet

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a magnetic path through which magnetic flux generated by the permanent magnet passes, and a magnetic path through which magnetic flux generated by energizing the coil passes are separately and independently generated

Methodology Applied

Scientific EffectMagnetic path separation: Magnetic Field

Data Source

PatentUS11049635B2Solenoid

Publication Date: 2021.06.29 NACHI FUJIKOSHI CORP

AI summary

Provided according to the present invention is a solenoid with a built-in permanent magnet, with which it is possible to suppress an increase in the amount of magnetic flux that passes through the chuck part, even when the magnetic flux generated by a coil is greater than the magnetic flux of the magnet, and to reliably reduce attraction force. In this solenoid, a permanent magnet and a coil are both built into a cylindrical case having an opening part; the permanent magnet and the coil are both separated and arranged inside the case; a ring member is arranged adjacent to the permanent magnet; a movable iron core is inserted inside the coil; and between the movable iron core and the coil, a metal coil cover is provided so as to cover the coil. The distance d between the case inner wall and the ring member can also be in the range of 0.1-0.3 mm.