Linear Compressor Magnet Fixation Without Adhesive for Cryocoolers

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The use of adhesives in linear compressors for cryocoolers leads to outgassing, which contaminates the refrigerant gas and reduces the cooling capacity over time, posing a risk to stable operation, especially in long-term applications like spacecraft where maintenance is impractical.

Innovation Solution

A linear compressor design that fixes a permanent magnet to a magnet holder without adhesives, using a pressing mechanism to secure the magnet in place, preventing outgassing and maintaining the cooling capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive is used to fix the magnet in the linear actuator, then the magnet can be securely fixed, but outgassing from the adhesive contaminates the refrigerant gas and decreases cooling capacity over time

Engineering Contradiction:
Improvemagnet fixation strengthVSAvoidadhesive outgassing contamination
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes the adhesive from the magnet fixation system entirely. Instead of using adhesive to fix the magnet to the magnet holder, a pressing mechanism (spring) is introduced to apply mechanical pressure, eliminating the source of outgassing contamination while maintaining secure magnet fixation.

Inventive Principle:
Principle #2Taking out (Extraction)

2Stability of the object's composition

If adhesive is used to fix the magnet, then the magnet can be fixed in place, but the adhesive contamination becomes irreversible in sealed systems like spacecraft cryocoolers

Engineering Contradiction:
Improvemagnet position stabilityVSAvoidlong-term operational reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The adhesive is extracted from the system and replaced with a mechanical pressing mechanism. This eliminates the irreversible contamination issue while maintaining magnet position stability through continuous spring pressure, ensuring long-term reliability in sealed spacecraft environments.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If adhesive is used for magnet fixation, then assembly is simplified, but maintenance and magnet replacement become impractical in sealed systems

Engineering Contradiction:
Improveassembly simplicityVSAvoidmagnet replacement difficulty
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The magnet fixation system is segmented into separable components: the magnet holder, the spring pressing mechanism, and the magnet itself. This segmentation allows the magnet to be independently removed and replaced by accessing the magnet holder, making maintenance practical while maintaining assembly simplicity through modular design.

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

This design suppresses the decrease in cooling capacity by eliminating outgassing and allowing for easier magnet replacement, ensuring stable operation without adhesive-related contamination issues.

Implementation Method 1

the magnet holder includes a pressing mechanism that presses the permanent magnet against the magnet receiving recessed part

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

a linear actuator that drives the piston in the axial direction

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3699426B1Linear compressor for cryocooler
Publication Date: 2021.09.22 SUMITOMO HEAVY IND LTD
  • EP3699426B1 patent drawingFigure 1
  • EP3699426B1 patent drawingFigure 2
  • EP3699426B1 patent drawingFigure 3

AI summary

A linear compressor (12) for a cryocooler (10) includes a piston (12a) that extends in an axial direction, a linear actuator (12b) that drives the piston (12a) in the axial direction, a housing (12c) that accommodates the piston (12a) and the linear actuator (12b) and supports the piston (12a) to be oscillatable in the axial direction. The linear actuator (12b) includes an outer yoke (26) that is fixed to the housing (12c), an inner yoke (28) that is disposed on a radially inner side of the outer yoke (26) and is fixed to the housing (12c), a magnet holder (30) that includes a magnet receiving recessed part (30a) positioned between the inner yoke (28) and the outer yoke (26) in a radial direction and is fixed to the piston (12a), and a permanent magnet (32) that is housed in the magnet receiving recessed part (30a) and is fixed to the magnet holder (30) without using an adhesive.