Adjustable Spring Mechanism for Electromagnetic Drive Vibration Control

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Solution Overview

Problem

Existing electromagnetic drive units in electric toothbrushes face challenges in converting linear oscillation into rotational motion efficiently, often resulting in undesirable vibrations and noise, especially when the frequency approaches the resonant frequency of the drive shaft and workpiece.

Innovation Solution

A spring mechanism is introduced that includes a housing, a movable spring connected to the housing, a drive shaft with a magnet, and adjustable tuning elements connecting the drive shaft to the spring, allowing for tension adjustment and control of the workpiece movement, enabling efficient conversion of electromagnetic movement into desired rotational motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the electromagnet frequency is increased to improve cleaning efficiency, then the cleaning performance is improved, but vibrations and noise increase due to approaching resonant frequency

Engineering Contradiction:
Improvecleaning efficiencyVSAvoidvibrations and noise
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the system adjustable through the spring tension mechanism. The spring tension can be dynamically modified to change the resonant frequency of the drive shaft and workpiece assembly, allowing the system to adapt to different operating conditions and avoid harmful resonance while maintaining high cleaning efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes physical parameters by adjusting the spring tension to modify the resonant frequency of the mechanical system. This parameter adjustment allows the electromagnet to operate at optimal frequencies for cleaning efficiency without coinciding with the resonant frequency that causes vibrations and noise.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the spring tension is increased to reduce vibrations, then vibrations and noise are reduced, but the workpiece movement amplitude decreases

Engineering Contradiction:
Improvevibrations and noiseVSAvoidworkpiece movement amplitude
Core Design Contradiction:
Object-affected harmful factorsVSSpeed

Solution Approach 1:

The patent applies dynamics by providing an adjustable spring tension mechanism that allows the user to optimize the balance between vibration reduction and movement amplitude. The system can be dynamically tuned to achieve the desired performance characteristics for different operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes physical parameters by allowing adjustment of spring tension to modify the system's vibrational characteristics and movement amplitude, enabling optimization of both vibration reduction and cleaning effectiveness.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If a fixed electromagnetic drive design is used to simplify manufacturing, then manufacturing complexity is reduced, but the ability to control and tune workpiece movement is limited

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidworkpiece movement control
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by introducing an adjustable spring tension mechanism that transforms a static system into a dynamically可调 system. This allows the same basic manufacturing design to provide multiple operational configurations for controlling workpiece movement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies segmentation by separating the spring tension adjustment function from the main electromagnetic drive assembly, allowing independent optimization of manufacturing simplicity while adding controllability through a modular adjustment mechanism.

Inventive Principle:
Principle #1Segmentation

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 spring mechanism effectively tunes the workpiece movement, reducing vibrations and noise, and allows for adjustable frequency and amplitude, enhancing the user experience by providing a more efficient and desirable motion for the toothbrush bristles.

Implementation Method 1

The electromagnet can be actuated by a switch to alternate polarity at a desired frequency. A movable permanent magnet (or a pair of permanent magnets) is positioned proximate to the electromagnet, such that the permanent magnet is driven to oscillate at an oscillating frequency by the electromagnet

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Implementation Method 2

A spring mechanism is introduced that includes a housing, a movable spring connected to the housing, a drive shaft with a magnet, and adjustable tuning elements connecting the drive shaft to the spring, allowing for tension adjustment and control of the workpiece movement

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3069833B1Spring mechanism for power device
Publication Date: 2018.09.19 RANIR LLC
  • EP3069833B1 patent drawingFigure 1~2
  • EP3069833B1 patent drawingFigure 3~5
  • EP3069833B1 patent drawingFigure 6~6A

AI summary

A spring mechanism for an electromagnetic drive unit converts or translates the movement and/or actuation of the electromagnet into a desired movement of the workpiece and enables simple and efficient tuning of the workpiece movement. The spring mechanism includes a housing, a spring connected to the housing, wherein at least two sections of the spring are movable with respect to the housing, a drive shaft that includes a first end having a magnet and a second end for attachment to a workpiece, and at least two tuning elements connecting the drive shaft to the movable portion of the spring. At least one of the tuning elements is adjustable. In one embodiment, the spring may be a flat spring, and the movable sections may each be positioned between a pair of cutouts defined in the spring.