Electromagnetic Drivetrain for Power Tapping and Sweeping Motion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current power toothbrush devices rely on rotary sweeping motion, which has limitations in cleaning efficiency, particularly in removing plaque from interproximal zones, gumline areas, and gum pockets, and are heavily dependent on user position and pressure.

Innovation Solution

Incorporating an electromagnetic assembly to generate a controllable power tapping motion parallel to the bristle direction, either coupled with or decoupled from the sweeping motion, using a drivetrain assembly that includes a motor and electromagnetic components to independently control the bristle movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rotary sweeping motion is used to clean teeth, then overall surface cleaning is achieved, but cleaning efficiency in interproximal zones and gum pockets is insufficient

Engineering Contradiction:
Improvecleaning efficiencyVSAvoidplaque removal effectiveness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the cleaning function into two distinct motion components: rotary sweeping motion for overall surface cleaning and linear tapping motion for interproximal and gum pocket cleaning. This segmentation allows each motion type to specialize in specific cleaning zones, resolving the contradiction between overall coverage and targeted effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of linear tapping motion perpendicular to the traditional rotary sweeping plane. By adding this vertical dimension of motion parallel to bristle orientation, the system achieves effective cleaning in previously inaccessible areas like gum pockets and interproximal zones while maintaining overall surface cleaning capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If two separate mechanical systems are used to drive tapping and sweeping motions, then controllable power tapping motion is achieved, but device cost, size, and complexity increase

Engineering Contradiction:
Improvecontrollable tapping motionVSAvoidmechanical system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the sweeping and tapping drive functions into a single integrated electromagnetic assembly. The stator generates magnetic fields that simultaneously control both the rotary sweeping motion and linear tapping motion of the brush head, eliminating the need for separate mechanical systems and reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electromagnetic assembly serves multiple functions: it generates both sweeping and tapping motions, provides independent control of each motion type, and replaces what would traditionally require separate motors and mechanical transmissions. This multi-functionality resolves the contradiction between controllability and complexity.

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

3Productivity

If bristles are subjected to heavy loads during cleaning, then thorough plaque removal is achieved, but bristles become trapped and cleaning efficiency suffers

Engineering Contradiction:
Improveplaque removalVSAvoidbristle performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements periodic linear tapping motion that rhythmically impacts the brush head against the teeth. This periodic action prevents bristles from becoming continuously trapped under heavy load by repeatedly resetting their position, maintaining cleaning efficiency while achieving thorough plaque removal through the combined sweeping and tapping motions.

Inventive Principle:
Principle #19Periodic action

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

Improves plaque and stain removal, achieves deeper gum pocket cleaning, reduces bristle constraint, and makes the device less dependent on user technique, enhancing overall cleaning performance.

Implementation Method 1

an electromagnetic assembly configured to drive the drivetrain shaft and the brush head member having bristles about a second axis of the device, different than the central axis, or in a direction parallel to a third axis of the device, that is different that the central axis

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4432973B1Drivetrain assemblies for generating sweeping motion and power tapping motion
Publication Date: 2025.09.24 KONINKLIJKE PHILIPS NV
  • EP4432973B1 patent drawingFigure 1~3
  • EP4432973B1 patent drawingFigure 4
  • EP4432973B1 patent drawingFigure 5~7

AI summary

Drivetrain assemblies for personal care devices using electromagnetic components to generate a combination of controllable power tapping and sweeping motions. The drivetrain assemblies include a drivetrain shaft at least partially contained within a body portion of the device. The drivetrain shaft is further configured to engage a brush head member of the device. The drivetrain assemblies further include a motor mounted on the drivetrain shaft, where the motor is configured to periodically rotate the drivetrain shaft about a first axis of the device, and an electromagnetic assembly configured to drive the drivetrain shaft and thereby the brush head member about an second axis of the device or in a direction parallel to a third axis of the device. The electromagnetic assembly includes a stator, a voice coil actuator, a rotor, or a linear solenoid actuator, for example.