Annular Linear Actuator Magnetic Circuit Design

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Solution Overview

Problem

Existing linear actuators, compressors, and pumps in household appliances face inefficiencies and complexity due to their design, which affects the electromagnetic force and resilience of these components.

Innovation Solution

A linear actuator comprising a stator with annular iron core elements and a solenoid coil, an annular magnet component with radially oriented permanent magnet segments, and an annular yoke, which together form a magnetic circuit that enhances efficiency and electromagnetic force by allowing full circumferential magnetic flux generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional linear actuator designs are used, then the device can operate, but the electromagnetic force is insufficient and efficiency is reduced

Engineering Contradiction:

Improveelectromagnetic forceVSAvoidefficiency

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The magnet component is segmented into multiple permanent magnet segments arranged circumferentially, creating multiple magnetic flux paths that increase the overall electromagnetic force while maintaining energy efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design transitions from conventional linear magnetic flux to three-dimensional circumferential magnetic flux by arranging permanent magnets in a circular pattern around the solenoid coil, utilizing radial and axial components simultaneously to enhance electromagnetic force

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If conventional linear actuator designs are used, then the device can operate, but the complexity and assembly effort are high

Engineering Contradiction:

ImprovecomplexityVSAvoidassembly effort

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The stator, magnet component, and yoke are integrated into a unified annular magnetic circuit structure where components share common geometric features and mounting interfaces, reducing the number of separate assembly operations required

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The annular yoke serves multiple functions simultaneously: it provides the magnetic flux return path, acts as a structural support for the permanent magnet segments, and forms part of the compression chamber boundary, eliminating the need for separate components for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If conventional linear actuator designs are used, then the device can operate, but the resilience is reduced

Engineering Contradiction:

ImproveresilienceVSAvoidresilience

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The magnetic circuit utilizes composite construction with soft magnetic composite material for the stator and yoke components, providing both magnetic conductivity and mechanical resilience, while the permanent magnet segments are securely retained in their radial positions within the annular structure

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Instead of mounting permanent magnets on the stator as in conventional designs, the permanent magnets are mounted on the moving plunger assembly, inverting the traditional arrangement to reduce stress on stationary components and improve overall system resilience

Inventive Principle:

Principle #13The other way round (Inversion)

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 proposed design achieves increased efficiency and electromagnetic force, reduces complexity and assembly effort, and enhances resilience of the linear actuator, compressor, and pump, leading to improved performance in household appliances.

Implementation Method 1

the linear actuator according to the present invention is configured to generate an alternating magnetic flux in response to alternately poled electric power input to the solenoid coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Mutual electromagnetic force between the permanent magnet, the inner stator, and the outer stator causes a linear motion of the permanent magnet

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4571107A1Linear actuator, compressor, pump, and household appliance

Publication Date: 2025.06.18 BOSCH SIEMENS HAUSGERATE GMBH

Figure 1a~1c

AI summary

Disclosed is a linear actuator 1 comprising a stator 10, an annular yoke 30, and an annular magnet component 20. The stator 10 comprises two annular iron core elements 11a, 11b and a solenoid coil 12 having a common centre axis X, wherein the iron core elements 11a, 11b are spaced apart from each other. The annular yoke 30 is assembled coaxial to and radially outwards of the iron core elements 11a, 11b. The annular magnet component 20 comprises a plurality of radially oriented permanent magnet segments 21 and is collocated radially between the stator 10 and the annular yoke 30 so as to be movable in axial direction. Further disclosed are a pump and a compressor respectively comprising such linear actuator 1, and a household appliance comprising such pump and/or such compressor.