Stirling Cycle Cooler One-Piece Support to Reduce Vibration and Noise

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Solution Overview

Problem

Current Stirling cycle cooling devices face challenges with vibration and acoustic noise due to hyperstatic mechanisms, lubricant contamination, and tight manufacturing tolerances, which increase production costs and friction losses.

Innovation Solution

A Stirling cycle cooling device with a one-piece support that integrates the compressor and regenerator cylinders, eliminating intermediate mechanical parts and using a single bearing for the crankshaft, along with an external rotor motor to reduce vibration and noise, and simplify assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If intermediate mechanical parts and multiple bearings are used to support the crankshaft, then the mechanism can accommodate manufacturing tolerances and ensure proper alignment, but the device complexity and friction losses increase

Engineering Contradiction:
Improvealignment toleranceVSAvoidnumber of mechanical parts
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the support structure for the crankshaft with the existing housing or frame of the cooling device, eliminating the need for separate intermediate mechanical parts and multiple bearings. The crankshaft is directly supported by integrated bearing surfaces formed as part of the main structure, reducing the number of components while maintaining proper alignment through precise monoblock manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing or frame structure serves multiple functions: it provides structural support, houses the compression and expansion spaces, and simultaneously supports the crankshaft through integrated bearing surfaces. This multi-functionality eliminates the need for dedicated intermediate support parts, reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If lubricant is used in kinematic connections, then friction and wear are reduced, but the refrigerant becomes contaminated and may blockage at cryogenic temperatures

Engineering Contradiction:
Improvereduction of friction and wearVSAvoidrefrigerant contamination
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the lubrication function from the kinematic connections by eliminating relative motion between the crankshaft and support structure. The crankshaft is designed to rotate within integrated bearing surfaces that accommodate motion without requiring lubricant, thereby removing the source of refrigerant contamination while maintaining reliable operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the traditional lubricated mechanical connection system with a bearing surface system that relies on distributed pressure and material compliance rather than lubricant films. This substitution eliminates the need for lubricant in the kinematic chain, preventing refrigerant contamination while still reducing friction and wear through proper bearing surface design.

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

3Ease of manufacture

If functional play is provided at the crankpin to limit hyperstatism, then assembly is simplified, but shocks and vibrations are generated due to alternating forces

Engineering Contradiction:
Improveassembly simplicityVSAvoidvibration and acoustic noise
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent merges the crankshaft support function with the main housing structure, eliminating the need for separate crankpin connections that would require functional play. The integrated bearing surfaces provide continuous support without gaps or clearance, preventing shocks and vibrations while simplifying assembly through monoblock construction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent incorporates bearing surfaces with inherent compliance and distributed pressure capabilities that cushion the alternating forces before they can generate shocks or vibrations. The bearing design anticipates the cyclic loading and provides continuous contact with slight deformation capacity, preventing impact loads and reducing vibration and noise.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 achieves a silent and low-vibration isostatic mechanism, reducing production costs and complexity while maintaining efficient cooling performance.

Implementation Method 1

The cooling is carried out by means of a refrigerant fluid circulating in a circuit

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 2

The regenerator includes a regeneration piston also movable in a second cylinder... acting as a heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

The two pistons are each driven by a connecting rod/crank system, consisting of a crankshaft (which can carry one or more crankpins) and one or more connecting rods. The crankshaft is driven in rotation by a rotary motor.

Methodology Applied
Scientific EffectMechanical conversion: Crankshaft

Implementation Method 4

isothermal compression of a fluid at a hot temperature, obtained by the movement of a compression piston in a compression cylinder

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3674626B1Stirling cycle cooling device with integral mounting
Publication Date: 2021.04.07 THALES SA
  • EP3674626B1 patent drawingFigure 1
  • EP3674626B1 patent drawingFigure 2
  • EP3674626B1 patent drawingFigure 3~4

AI summary

The invention relates to a cooling device implementing a reverse Stirling thermodynamic cycle. The device (10) comprises a reciprocating piston compressor (16) driven by a rotary motor (14) about an axis (24) via a crankshaft (46). The device (10) further comprises a one-piece support (32) forming a cylinder (18) in which the piston (16) of the compressor (12) moves. The crankshaft (46) is supported by a single bearing (40). The bearing (40) is arranged without an intermediate part in a housing (38) of the one-piece support (32).