Linear Compressor Mover Wave Retaining Ring Thermal Compensation

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Solution Overview

Problem

Linear compressors with linear electric motors are prone to damage from severe temperature changes during refrigerant compression, which can shorten their service life.

Innovation Solution

The linear compressor design incorporates a mover with a magnet ring, yoke, and cylinder, equipped with wave retaining rings to cushion compressive forces and compensate for thermal expansions and contractions, ensuring reliable operation across varying temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the linear compressor operates during refrigerant compression, then cooling effect is achieved, but severe temperature changes damage moving parts and shorten service life

Engineering Contradiction:
Improveservice lifeVSAvoidtemperature changes
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by introducing a damping element between the cylinder and the piston that anticipates and absorbs thermal expansion forces before they can damage the moving parts. The damping element is pre-installed in the compression chamber to cushion against future thermal stress during operation.

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

Solution Approach 2:

The patent applies parameter changes by modifying the physical state of the damping element to accommodate thermal expansion. The damping element changes its stiffness or damping characteristics in response to temperature changes, allowing it to effectively cushion thermal expansion forces while maintaining proper function across the operating temperature range.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the cylinder moves linearly to minimize friction, then energy loss is reduced, but thermal expansion causes misalignment and increased friction

Engineering Contradiction:
Improveenergy lossVSAvoidalignment stability
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The damping element is installed beforehand in the compression chamber to cushion thermal expansion before it causes misalignment. This pre-positioned cushioning element absorbs the thermal growth of the cylinder, preventing it from pushing the piston out of alignment and maintaining stable friction characteristics throughout operation.

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

Solution Approach 2:

The patent applies local quality by placing the damping element specifically at the location where thermal expansion occurs (in the compression chamber between cylinder and piston). This localized solution addresses the thermal expansion problem at its source without affecting other parts of the compressor, maintaining linear motion efficiency while stabilizing alignment locally.

Inventive Principle:
Principle #3Local quality

3Reliability

If components are made of different materials with different thermal expansion coefficients, then thermal compensation is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvethermal compensationVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The damping element is designed with specific material parameters (thermal expansion coefficient, stiffness, damping characteristics) that change or adapt to compensate for thermal expansion. By carefully selecting and tuning these parameters, the patent achieves effective thermal compensation through a single well-designed component rather than complex multi-material assemblies.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The damping element may utilize composite material structures that combine materials with different thermal expansion properties to achieve near-zero thermal expansion or controlled expansion characteristics. This allows the single component to compensate for thermal effects in the overall assembly without requiring multiple different materials to be precisely fitted together.

Inventive Principle:
Principle #40Composite materials

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 effectively compensates for thermal expansions and contractions, enhancing the operational reliability and extending the service life of the linear compressor by mitigating the effects of severe temperature changes.

Implementation Method 1

The elastic properties of the first wave retaining ring in the first circular groove in the yoke next to the magnet ring make it possible to cushion the compressive forces and compensate for the expansion and contraction of the components of the mover caused by temperature changes.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a linear electric motor can have a stator in the form of a cylindrical coil with further stator segments and the mover inside the stator

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4571108A1Linear compressor with a linear electric motor
Publication Date: 2025.06.18 BOSCH SIEMENS HAUSGERATE GMBH
  • EP4571108A1 patent drawingFigure 1~2
  • EP4571108A1 patent drawingFigure 3~4
  • EP4571108A1 patent drawingFigure 5

AI summary

The invention relates to a linear compressor (1) with a linear electric motor comprising a stator (2) with a coil (3) and a mover (4), wherein the mover (4) has a magnet ring (5) made of a permanent magnet, a yoke (6) for distributing the magnetic field and a cylinder (7), wherein a first wave retaining ring (8) is arranged in a first circular groove (9) in the yoke (6) next to the magnet ring (5).