Electric Toothbrush Linkage Mechanism for Smooth Low-Noise Rotation

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Solution Overview

Problem

Existing rotating toothbrush designs, such as those using gear or runway groove mechanisms, suffer from unstable quality due to high assembly precision requirements and irregular movement, leading to deformation and increased power consumption.

Innovation Solution

A rotating mechanism for electric toothbrushes that connects the eccentric wheel and drive shaft through two connecting rods and a swing rod, allowing for stable and smooth transmission, reducing power consumption and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gear engagement is used to achieve eccentric positions, then the rotating toothbrush can be driven, but extremely high requirements on gear clearance are needed resulting in unstable quality

Engineering Contradiction:
Improveproduct quality stabilityVSAvoidgear clearance requirement
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces a runway groove as an intermediary element between the eccentric wheel and the connecting rod. The runway groove guide hole and runway groove connecting rod form a guided connection that mediates the motion transmission, eliminating the need for precise gear clearance while maintaining reliable motion transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If runway groove connecting rod driven by eccentric wheel is used, then the rotating toothbrush can be driven, but the large contact area and forced change of movement direction cause irregular movement and deformation

Engineering Contradiction:
Improvemovement regularityVSAvoidcontact area between components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the motion transmission path into distinct rotational and translational components. The eccentric wheel provides rotational motion, while the runway groove connecting rod converts it to translational motion of the drive shaft, avoiding forced directional changes and irregular movement.

Inventive Principle:
Principle #1Segmentation

3Duration of action of moving object

If conventional rotating mechanisms are used, then the toothbrush can rotate, but power consumption increases and functional life is reduced

Engineering Contradiction:
Improvefunctional lifeVSAvoidpower consumption
Core Design Contradiction:
Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent employs dynamic motion conversion where the eccentric wheel's rotation is transformed into the drive shaft's translational oscillation through the runway groove mechanism. This dynamic conversion optimizes energy utilization, reducing power consumption and extending the functional life of the battery-powered toothbrush.

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 mechanism achieves stable and smooth operation, reducing power consumption and noise while prolonging the functional life of the electric toothbrush.

Implementation Method 1

an eccentric wheel arranged on an output shaft of the motor; the first connecting rod is respectively rotatably connected to a wheel axle of the eccentric wheel and a second end of the swing rod; when the eccentric wheel rotates, the swing rod is driven by the first connecting rod to swing relative to the motor holder within a preset angle range

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Implementation Method 2

The connecting rod assembly comprises a first connecting rod and a second connecting rod; the first connecting rod is respectively rotatably connected to a wheel axle of the eccentric wheel and a second end of the swing rod; the second connecting rod is respectively rotatably connected to the drive shaft and a second end of the eccentric wheel

Methodology Applied
Scientific EffectMechanical force transmission: Mechanical Force

Data Source

PatentEP4729024A1Rotating mechanism and electric toothbrush
Publication Date: 2026.04.22 GUANGDONG XINBAO ELECTRICAL APPLIANCES HLDG CO LTD
  • EP4729024A1 patent drawingFigure 1~2
  • EP4729024A1 patent drawingFigure 3~4
  • EP4729024A1 patent drawingFigure 5~6

AI summary

A rotating mechanism and an electric toothbrush. The electric toothbrush comprises a motor (16), an eccentric wheel (17) provided on an output shaft of the motor (16), and a drive shaft (18), wherein the drive shaft (18) is provided with a brush head. A rotating drive mechanism comprises: a motor holder (10) for mounting the motor (16); a swing rod (11), a first end of which is rotationally connected to the motor holder (10); and a connecting rod assembly (12), which comprises a first connecting rod (121) and a second connecting rod (122), the first connecting rod (121) being rotationally connected to both a wheel axle of the eccentric wheel (17) and a second end of the swing rod (11), and the second connecting rod (122) being rotationally connected to both the drive shaft (18) and the second end of the swing rod (11). When the eccentric wheel (17) rotates, the swing rod (11) can be driven by means of the first connecting rod (121) to swing relative to the motor holder (10) within a preset angle range, and when the swing rod (11) swings, the drive shaft (18) is driven by means of the second connecting rod (122) to swing synchronously. The rotating mechanism has low assembly precision requirements and involves stable and smooth transmission.