Electric Toothbrush Motor Eliminating Elastic Structures

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Solution Overview

Problem

Conventional electric toothbrush motors have a low carrying capacity and short service life due to the use of easily damaged elastic structures, resulting in unstable oscillation and limited torque per unit volume.

Innovation Solution

A motor device with a stator core, coil winding, insulating coil holder, and magnetic steel structures fixed to a shaft coupling, which generates a magnetic field to drive the motor shaft via electromagnetic effect, eliminating the need for elastic structures and enhancing torque and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastic structures (spring or torsion bar) are installed in the motor, then the motor can be driven to oscillate, but the service life is short and reliability is low due to easy damage

Engineering Contradiction:
Improveservice lifeVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the elastic structures (spring or torsion bar) from the motor system entirely. The oscillation function is achieved through the interaction between the magnetic steel structures on the shaft coupling and the stator core poles, eliminating the need for separate elastic components and their associated reliability issues.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical elastic structure-based oscillation system with an electromagnetic field-based system. The magnetic steel structures interact with the stator poles through magnetic fields to produce oscillation, substituting mechanical elasticity with electromagnetic forces.

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

2Power

If conventional motor structures are used, then the motor can operate, but the torque per unit volume is low and carrying capacity is limited

Engineering Contradiction:
Improvetorque per unit volumeVSAvoidmotor volume
Core Design Contradiction:
PowerVSVolume of stationary object

Solution Approach 1:

The patent uses magnetic steel structures with specific magnetic properties positioned at specific locations on the shaft coupling periphery. These localized magnetic elements create concentrated magnetic fields that interact with the stator poles to generate high torque density in a compact volume.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent combines magnetic steel structures with non-magnetic materials to create a composite rotor assembly. This composite structure optimizes both magnetic performance for high torque and structural integrity, achieving high torque per unit volume.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If the motor shaft is subjected to different loads, then the motor can adapt to various conditions, but the oscillation range varies greatly and application effect is unstable

Engineering Contradiction:
Improveload adaptationVSAvoidoscillation stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent creates a dynamic magnetic interaction system where the magnetic steel structures on the rotating shaft coupling continuously interact with the stator poles. This dynamic electromagnetic coupling maintains stable oscillation characteristics across different load conditions, as the magnetic field interaction automatically adapts to load variations.

Inventive Principle:
Principle #15Dynamics

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 motor device achieves a longer service life, greater torque per unit volume, reduced size and weight, and stable power transmission, improving user experience and oscillation consistency.

Implementation Method 1

generates a magnetic field to drive the motor shaft via electromagnetic effect

Methodology Applied
Scientific EffectElectromagnetic effect: Electromagnetic Induction

Data Source

PatentEP3379698B1Electric toothbrush and motor device thereof
Publication Date: 2020.02.12 JINLONG MASCH & ELECTRONICS DONGGUAN CO LTD
  • EP3379698B1 patent drawingFigure 1~2
  • EP3379698B1 patent drawingFigure 3~4

AI summary

A motor device includes a motor housing, a stator core having at least two poles fixedly installed in the stator housing symmetrically, a coil winding wound around the stator core, and an insulating coil holder for insulating the stator core from the coil winding, and the motor device further includes at least two pairs of magnetic steel structures cooperating with the stator core. All of the magnetic steel structures are fixedly connected to the periphery of the shaft coupling, and the shaft coupling is fixedly connected to the motor shaft. By adopting the above structural design, the movement transmission is realized by electromagnetic effect, and elastic structures such as a torsion bar is no longer needed. Thus, on the one hand, the problem that the service life of the motor is short because the elastic structure is easily damaged during use is avoided, and on the other hand, the motor can have a greater torque per unit volume, which, on the premise of reaching the rated torque, reduces the size of the motor as much as possible and reduces the weight of the electric toothbrush as much as possible, thereby improving the user experience. An electric toothbrush having the above motor device is further provided.