Sonic Toothbrush Brush Geometry for Controlled Figure-Eight Bristle Motion
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Solution Overview
Problem
Current sonic toothbrushes lack a defined and controlled two-dimensional bristle movement, leading to inefficient cleaning and potential harm to gums, while existing technologies fail to effectively apply manual toothbrush cleaning principles to sonic toothbrushes.
Innovation Solution
A sonic toothbrush design featuring a brush head with a specific bending angle (8° to 15°) and modulus of elasticity (2000 to 6000 MPa) that generates a figure-eight motion, combining longitudinal and perpendicular bristle movements for enhanced cleaning and gum protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the brush head is designed to rotate around an axis parallel to the bristle direction, then the moving part size is reduced and drive energy requirement is lowered, but the bristle movement becomes inhomogeneously distributed across the bristle field
Solution Approach 1:
The patent transitions from one-dimensional rotation around an axis parallel to bristles to two-dimensional oscillation around a pendulum axis perpendicular to both handle and brush longitudinal axes. This dimensional change allows homogeneous bristle movement distribution while maintaining compact design and low energy consumption.
Solution Approach 2:
The patent employs asymmetric oscillation geometry where the pendulum axis is positioned to create optimal movement patterns. The brush head oscillates in an arc rather than rotating symmetrically, creating homogeneous bristle engagement across the entire bristle field while maintaining mechanical efficiency.
2Manufacturing precision
If the brush oscillates around a pendulum axis perpendicular to the handle and brush, then the bristle movement intensity is homogeneously distributed, but relatively large forces occur due to the brush head mass being far from the pendulum axis
Solution Approach 1:
The patent optimizes the pendulum axis position and brush head mass distribution to balance oscillation force requirements. By carefully selecting the pendulum axis location and adjusting the center of gravity position, the system achieves homogeneous bristle movement with minimized oscillation forces through parameter optimization.
3Device complexity
If the entire housing is vibrated to transmit cleaning motion, then the technical details of motion transmission are simplified, but more drive energy is required and the vibration strength must be limited for comfort
Solution Approach 1:
The patent extracts the vibration generation function from the entire housing and concentrates it in a compact drive unit. Only the necessary components (drive unit and brush head) are vibrated, while the handle housing remains stationary, reducing energy consumption while maintaining simple motion transmission.
4Productivity
If the brush neck is made more flexible to allow greater movement, then the cleaning action is enhanced, but the brush head stability decreases and uncontrolled movement occurs
Solution Approach 1:
The patent optimizes the neck section material properties and geometric dimensions to achieve the desired balance. By selecting appropriate material composition and cross-sectional area, the neck provides sufficient flexibility for effective cleaning movement while maintaining adequate stiffness to prevent uncontrolled brush head movement.
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 figure-eight motion provides a gentle yet effective cleaning action, improving access to interdental spaces and optimizing cleaning efficiency while minimizing gum damage.
Implementation Method 1
The base body (10) has a bend angle and a modulus of elasticity such that the longitudinal axis vibrations generate a figure-eight motion
Implementation Method 2
sonic toothbrush drive with longitudinal axis vibration... generates a longitudinal axis vibration
Data Source
Figure 1~3
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Figure 9~11
AI summary
A brush (10) for a sonic toothbrush with longitudinal axis vibration has an elongated base body with a foot section (11) and a drive adapter (14) for rotationally fixed coupling to a sonic toothbrush drive with longitudinal axis vibration, the drive adapter (14) defining a geometric longitudinal axis of the brush. The base body further has a head section (13) with a head section alignment axis (21) and a bristle carrier in which a plurality of bristles are anchored, the bristles projecting substantially perpendicularly from the head section alignment axis (21) of the brush (10). The base body also has an elongated neck section (12) connecting the foot section (11) and the head section (13). The basic body forms a kink angle such that the geometric longitudinal axis of the foot section (20) and a geometric alignment axis of the head section (21) enclose an angle γ (gamma) in the range of 8° to 15°.The main body is made of a load-bearing material with a modulus of elasticity of no more than 6000 MPa and no less than 2000 MPa. A sonic toothbrush with longitudinal axis vibration comprises a brush (10) and a handle with a brush coupling for detachably attaching the brush (10) to the handle, as well as a drive (16) that generates a longitudinal axis vibration at the brush coupling. The sonic toothbrush achieves a better cleaning effect, particularly gentle on the gums. In particular, a defined and controlled two-dimensional movement of the bristles is generated.