Compact Electric Toothbrush Motor Nesting

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Solution Overview

Problem

Conventional electric toothbrushes are bulky and inconvenient for portability due to their size, which compromises their usability when carried in bags or pockets, despite providing superior brushing performance.

Innovation Solution

The design incorporates a toothbrush head with a brush attachment shaft tube that is biased towards the rear of the main body case, a cap to accommodate the toothbrush head, and a main body case with a motor and battery accommodation portion, along with seal rings for watertightness, allowing the motor to be press-fitted into the shaft tube, ensuring efficient oscillation transmission and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the toothbrush includes an oscillation generator, battery, and other components, then the teeth brushing performance is improved, but the toothbrush becomes bulky and inconvenient for portability

Engineering Contradiction:
Improveteeth brushing performanceVSAvoidtoothbrush size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The toothbrush is divided into two separable parts: a compact main body containing the oscillation generator and battery, and a removable toothbrush head. This segmentation allows the main body to be small and portable while the head can be replaced or stored separately, resolving the contradiction between having complete functionality and maintaining compact size for portability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The brush attachment shaft tube is arranged biased toward the rear surface side of the main body case, utilizing the longitudinal dimension of the main body to accommodate the shaft tube. This spatial arrangement allows the oscillation transmission mechanism to be integrated within the compact main body volume without increasing the overall footprint, enabling portable size while maintaining brushing functionality.

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

2Productivity

If the brush attachment shaft tube is arranged in the main body case, then oscillation transmission efficiency is improved, but the main body case size increases

Engineering Contradiction:
Improveoscillation transmission efficiencyVSAvoidmain body case volume
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The brush attachment shaft tube is arranged biased toward the rear surface side of the main body case, utilizing the longitudinal dimension rather than increasing lateral dimensions. This spatial optimization allows the shaft tube to be integrated within the existing main body volume, maintaining compact size while achieving effective oscillation transmission from the motor to the toothbrush head.

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

Solution Approach 2:

The brush attachment shaft tube is nested within the main body case structure, with the motor positioned to drive the shaft tube. This nested arrangement allows the transmission mechanism to be contained within the main body volume without requiring additional external space, resolving the contradiction between transmission efficiency and compact dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 configuration results in a compact, portable electric toothbrush that maintains superior teeth brushing performance, with improved ergonomics and protection of the brush head, preventing accidental activation and maintaining hygiene during storage.

Implementation Method 1

the toothbrush rotates an eccentric weight with a motor to generate oscillation and transmit the oscillation to the toothbrush bristles

Methodology Applied
Scientific EffectEccentric rotation: Eccentric

Implementation Method 2

The inner case is accommodated in the outer case so that the motor accommodation portion is press-fitted into the brush attachment shaft tube of the outer case

Methodology Applied
Scientific EffectPress-fit: Mechanical Fastener

Implementation Method 3

the main body case includes an outer case, which includes the brush attachment shaft tube, and an inner case, which includes a motor accommodation portion that accommodates the motor at one end and a battery accommodation portion that accommodates a battery for driving the motor at another end. The inner case is accommodated in the outer case so that the motor accommodation portion is press-fitted into the brush attachment shaft tube of the outer case

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP2517668B2Electric toothbrush
Publication Date: 2020.03.04 PANASONIC HOLDINGS CORP
  • EP2517668B2 patent drawingFigure 1~4
  • EP2517668B2 patent drawingFigure 5
  • EP2517668B2 patent drawingFigure 6

AI summary

On a tip of a main body case (2) is formed a cylindrical brush attachment barrel (11) to which a toothbrush head (5) (holding unit (51)) is removably attached. In a space (S1) within the cylindrical brush attachment barrel (11) is disposed a motor (M) to which an eccentric weight (29) generating vibration is attached. Therefore, it is possible for the tip of the toothbrush head (5) to approach the main body case (2) side by the length of the cylindrical brush attachment barrel (11), thereby shortening the total length of an electric toothbrush (1).