Rocket Fuel Pump Magnetic Coupling to Eliminate Shaft Leakage

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Solution Overview

Problem

Rocket fuel pumps with mechanical bearings suffer from fuel leakage through the rotating shaft, which is a significant issue for long-duration rocket engines as it affects the engine's service life.

Innovation Solution

A magnetic coupling system is implemented, using permanent magnets on both the rotating shaft and drive shaft to magnetically couple them, eliminating the need for mechanical contact and thus preventing fuel leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a mechanical bearing is used to support the rotating shaft, then the rotating shaft can be rotatably supported, but fuel leakage occurs between the rotating shaft and the casing

Engineering Contradiction:
Improverotational supportVSAvoidfuel leakage
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The patent replaces the mechanical bearing system with a magnetic coupling system. The magnetic coupling includes drive side magnets on the drive shaft and driven side magnets on the rotating shaft, transmitting rotational force through magnetic fields without mechanical contact. This eliminates the fuel leakage path that exists in mechanical bearing systems while maintaining the rotational support function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Loss of substance

If a sealing mechanism is provided between the rotating shaft and the casing, then fuel leakage is reduced, but the leakage amount cannot be made zero and leaked fuel is discarded

Engineering Contradiction:
Improvefuel leakage reductionVSAvoidservice life
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

Instead of using sealing mechanisms that reduce but cannot eliminate leakage, the patent completely eliminates the leakage source by replacing the mechanical contact system with a magnetic coupling system. The magnetic coupling transmits torque through magnetic fields across a gap, creating no physical fuel leakage path and enabling near-zero fuel loss.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If permanent magnets are used in the magnetic coupling, then fuel leakage is prevented, but the structure becomes more complex with multiple magnets arranged at specific polarities

Engineering Contradiction:
Improvefuel leakage preventionVSAvoidmagnetic coupling structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic coupling is segmented into distinct drive side magnets and driven side magnets with specific polarity arrangements. The drive side magnets include alternating N and S poles, while the driven side magnets have corresponding polarity patterns. This segmentation allows for systematic design and assembly while achieving effective magnetic coupling without excessive complexity.

Inventive Principle:
Principle #1Segmentation

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 magnetic coupling effectively prevents rocket fuel from leaking through the rotating shaft, enhancing the reliability and longevity of long-duration rocket engines by reducing fuel loss.

Implementation Method 1

a magnetic coupling which is configured to magnetically couple the rotating shaft and a drive shaft of the drive source

Methodology Applied
Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

the magnetic coupling includes a plurality of driven side magnets provided on the rotating shaft and a plurality of drive side magnets provided on the drive shaft of the drive source, the driven side magnets and the drive side magnets are permanent magnets

Methodology Applied
Scientific EffectMagnetic force between permanent magnets: Magnetism

Data Source

PatentEP3543517B1Pump for rocket fuel
Publication Date: 2024.07.24 IHI CORP
  • EP3543517B1 patent drawingFigure 1
  • EP3543517B1 patent drawingFigure 2A~2B
  • EP3543517B1 patent drawingFigure 2C

AI summary

The present invention provides a rocket fuel pump including a rotating body (4) mounted on a rotating shaft (3) and pressure-feeding rocket fuel when the rotating body (4) is rotationally driven by a drive source (T), and the rocket fuel pump includes a magnetic coupling (R) which is configured to magnetically couple the rotating shaft (3) and a drive shaft (10) of the drive source (T).