Electric Toothbrush Motor Assembly for Stable Position Feedback

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Solution Overview

Problem

The mounting of the position feedback member in existing electric toothbrushes is not stable, leading to poor control over the brush head assembly.

Innovation Solution

A motor assembly for an electric toothbrush that includes a mounting seat fixedly sleeved on the output shaft, with a position feedback member rotatable within a mounting slot and a position sensor spaced apart to detect the feedback member's motion position, enhancing stability and reducing mounting force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the position feedback member is mounted directly on the output shaft without a mounting seat, then the device complexity is reduced, but the mounting stability deteriorates

Engineering Contradiction:
Improvestructure complexityVSAvoidmounting stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a mounting seat as an intermediary component between the output shaft and the position feedback member. The mounting seat provides a stable mounting platform with a dedicated mounting slot, ensuring reliable fixation of the position feedback member while maintaining a clear separation of functions and reducing overall structural complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the position sensor is mounted close to the mounting seat, then the device complexity is reduced, but the detection accuracy deteriorates

Engineering Contradiction:
Improvestructure complexityVSAvoidposition detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by creating a localized detection space between the position sensor and the mounting seat. This spatial separation ensures that the position sensor can accurately detect the position feedback member's movement without interference from the mounting seat structure, while the rest of the system maintains compact dimensions.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the mounting slot is made large to accommodate the position feedback member, then the ease of manufacture is improved, but the mounting stability deteriorates

Engineering Contradiction:
Improveassembly easeVSAvoidmounting stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent resolves this contradiction by transitioning from a single-dimensional fit to a multi-dimensional engagement. The mounting slot is designed with specific width and depth dimensions that work together with corresponding features on the position feedback member, creating a stable three-dimensional connection that is both easy to manufacture and highly stable.

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

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 the reliability of position detection and control over the brush head assembly by stabilizing the position feedback member, preventing damage and ensuring a stable oscillation process.

Implementation Method 1

a position sensor, spaced apart from the mounting seat and disposed on a side toward which an opening of the mounting slot is oriented; wherein the position sensor is configured to detect a motion position of the position feedback member

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP4461259B1Motor assembly and brush handle assembly for electric toothbrush, and electric toothbrush
Publication Date: 2025.11.19 SHENZHEN SHUYE INNOVATION TECH CO LTD
  • EP4461259B1 patent drawingFigure 1
  • EP4461259B1 patent drawingFigure 2
  • EP4461259B1 patent drawingFigure 3

AI summary

A motor assembly for an electric toothbrush, a brush handle assembly for an electric toothbrush, and an electric toothbrush. The motor assembly includes: a motor body, a mounting seat, a position feedback member, and a position sensor. The motor body is arranged with an output shaft. The mounting seat defines a connection hole; wherein the mounting seat is fixedly sleeved on the output shaft through the connection hole to be rotatable with the output shaft; the mounting seat further defines a mounting slot disposed on a peripheral side of the connection hole. The position feedback member is arranged at the mounting slot to be rotatable with the output shaft. The position sensor is spaced apart from the mounting seat and disposed on a side toward which an opening of the mounting slot is oriented; wherein the position sensor is configured to detect a motion position of the position feedback member.