Magnetic Shielding in Electric Shaver Drive Unit

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Solution Overview

Problem

In compact personal care devices like electric shavers, existing magnetic shielding solutions are difficult to integrate without increasing the device's size, as they require additional space and complex mounting structures to prevent magnetic field propagation, which can interfere with other appliances and user safety.

Innovation Solution

The magnetic shielding is integrated into a structural part of the drive train, made of soft magnetic material, surrounding the magnetically interacting components, thereby serving both as a shield and a support for the drive unit, eliminating the need for additional space and simplifying installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a magnetic shielding is added to prevent magnetic field propagation, then user safety and interference prevention are improved, but the device size and complexity increase

Engineering Contradiction:
Improvemagnetic field propagationVSAvoiddevice size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The magnetic shielding is merged with the drive support structure. The drive support serves dual functions: mechanically supporting the drive unit and providing magnetic shielding through its ferromagnetic material composition. This integration eliminates the need for separate shielding components, maintaining safety while preserving compact device dimensions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The drive support is designed with multi-functionality, acting both as a mechanical mounting structure and as a magnetic shield. By using ferromagnetic materials in the drive support, it simultaneously provides structural support and magnetic field containment, reducing the overall component count and device volume.

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

2Object-affected harmful factors

If a magnetic shielding is added to prevent magnetic field propagation, then user safety and interference prevention are improved, but the device complexity and mounting structure complexity increase

Engineering Contradiction:
Improvemagnetic field propagationVSAvoidmounting structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The magnetic shielding function is merged into the existing drive support structure. This integration eliminates the need for separate shielding components and their associated mounting hardware, thereby reducing device complexity while maintaining effective magnetic field containment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The drive support is designed with multi-functionality, acting both as a mechanical mounting structure and as a magnetic shield. By using ferromagnetic materials in the drive support, it simultaneously provides structural support and magnetic field containment, reducing the overall component count and device complexity.

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

3Object-affected harmful factors

If additional magnetic shielding components are added, then magnetic field containment is improved, but the available space for other components is reduced

Engineering Contradiction:
Improvemagnetic field containmentVSAvoidavailable space
Core Design Contradiction:
Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The magnetic shielding is merged with the drive support structure. The drive support serves dual functions: mechanically supporting the drive unit and providing magnetic shielding through its ferromagnetic material composition. This integration eliminates the need for separate shielding components, maintaining safety while preserving compact device dimensions.

Inventive Principle:
Principle #5Merging (Combining)

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 approach effectively reduces magnetic field propagation while maintaining a compact design, ensuring efficient magnetic shielding without adding bulk or requiring redesign of ergonomic housings, thus enhancing user safety and device functionality.

Implementation Method 1

a magnetic shielding at least partially surrounding said drive unit

Methodology Applied
Scientific EffectMagnetic shielding: Magnetic Field

Implementation Method 2

drive unit having first and second drive components adapted to magnetically interact with each other

Methodology Applied
Scientific EffectMagnetic interaction: Magnetic Field

Implementation Method 3

The said electric drive may include an electric or magnetic type linear motor

Methodology Applied
Scientific EffectLinear motor: Linear Motor

Data Source

PatentEP3396821B1Electric shaver
Publication Date: 2023.06.14 BRAUN GMBH
  • EP3396821B1 patent drawingFigure 1
  • EP3396821B1 patent drawingFigure 2
  • EP3396821B1 patent drawingFigure 3

AI summary

The present invention relates to electric appliances for personal care, in particular electric shavers, comprising a drive unit having first and second drive components adapted to magnetically interact with each other, and a magnetic shielding at least partially surrounding the drive unit. Said magnetic shielding is formed by structural parts supporting the drive unit and/or transmitting drive movements of the drive unit, wherein such structural parts are made of a soft magnetic material. More particularly, a mounting frame and a transmitter frame together form a magnetic shielding cage which is movable as the mounting frame and the transmitter frame are movable relative to each other.