Ferrofluid Shaft Seal for Swing and Movement

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing sealed bearing assemblies fail to maintain a reliable seal when the shaft is adjusted in angle or displaced, especially under high-speed rotation, high temperature, or alkaline conditions, leading to leakage and increased costs due to inadequate sealing mechanisms.

Innovation Solution

A sealed bearing assembly incorporating a bellows with a fixed and free end, a cylindrical sealing ring, and ferrofluid attracted by magnetic forces to form a shaft seal, allowing linear and rotational movement of the shaft without compromising the sealing effect, using a ferrofluid composed of magnetic particles, surfactant molecules, and a liquid carrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a general seal is used to prevent leakage, then sealing effect is maintained, but the seal cannot work under high rotational speed, high temperature, or alkaline conditions

Engineering Contradiction:

Improvesealing effectVSAvoidadaptability to high speed, temperature, and chemical conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the sealing mechanism from a static mechanical seal to a dynamic magnetic seal using ferrofluid. The ferrofluid's magnetic properties allow it to maintain sealing under varying conditions (high speed, temperature, chemical exposure) by responding to magnetic field changes rather than relying on mechanical contact, thus adapting to different operational parameters.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses ferrofluid, a composite material consisting of ferromagnetic particles suspended in a carrier fluid. This composite enables the seal to function under conditions where traditional single-material seals fail, combining magnetic responsiveness with fluidity to maintain sealing effectiveness across diverse environmental conditions.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If the shaft is adjusted for displacement and swing, then adaptability is improved, but the sealing effect is damaged

Engineering Contradiction:

Improveshaft adjustment capabilityVSAvoidsealing effect

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a dynamic sealing system where the ferrofluid continuously adapts to shaft movement. Unlike static seals that fail with displacement, the ferrofluid maintains its magnetic barrier dynamically, allowing the shaft to swing and displace while preserving the sealing effect through real-time magnetic field adjustment.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The ferrofluid acts as an intermediary between the moving shaft and the stationary seal housing. It transfers the sealing function from a rigid mechanical interface to a flexible magnetic field interface, enabling shaft adjustment while maintaining the seal through the ferrofluid's ability to conform to positional changes.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If air or gas curtain isolation is used, then shaft adjustment is enabled, but crystallization problem occurs and costs rise

Engineering Contradiction:

Improveshaft movement capabilityVSAvoidcrystallization and cost

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the mechanical air/gas curtain isolation system with a magnetic field-based ferrofluid seal. This substitution eliminates the crystallization problem associated with gas curtains and reduces costs by using a more efficient sealing mechanism that enables shaft movement without the harmful side effects of the previous system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 maintains a good sealing effect across various conditions, including high rotational speeds, temperature ranges, and linear displacements, preventing gas and liquid leakage while allowing shaft adjustment, as demonstrated by experimental results achieving 1*E-7 torr vacuum, 2 atm pressure difference, and 0˜80° C temperature range.

Implementation Method 1

a ferrofluid being attracted by a magnetic force of the external magnetic ring to be distributed on a surface of the shell toward the shaft

Methodology Applied

Scientific EffectMagnetic force: Magnetism

Implementation Method 2

a ferrofluid being attracted by a magnetic force of the external magnetic ring to be distributed on a surface of the shell toward the shaft, wherein when the shaft moves linearly relative to the shell and the inner magnetic ring moves with the sealing ring to a section of the external magnetic ring, a magnetic force is generated between the inner magnetic ring and the section of the external magnetic ring to attract the ferrofluid to flow, and thus the ferrofluid forms a shaft seal between the inner magnetic ring and the section of the external magnetic ring by surrounding a periphery of the sealing ring to block gas or liquid in the sealing ring

Methodology Applied

Scientific EffectFerrofluid: Ferrofluid