Electric Toothbrush Head Support Shaft Forward Positioning
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Solution Overview
Problem
Existing electric toothbrushes face issues with increased size in the front-rear direction due to the location of the head support shaft, leading to reduced operability, especially in cleaning the back side of molar teeth, and increased frictional resistance, which affects stability and power consumption.
Innovation Solution
The electric toothbrush design features a head support shaft located forward of the planting base's rear surface, with a power transmission portion connected to the rear of the fitting shaft, reducing the moment on the brush head and enhancing stability, while the head-side conversion portion includes a swing lever to convert linear motion to rotational motion, minimizing the stroke of the connection bar and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the head support shaft is located rearward of the planting base to ensure sufficient fitting length and reduce looseness, then the brush head size in the front-rear direction increases, but the operability in the oral cavity deteriorates
Solution Approach 1:
The patent moves the head support shaft from a rearward position to a forward position relative to the planting base, changing the spatial dimension of the support structure. This dimensional repositioning allows the shaft to extend forward of the planting base, reducing the front-rear thickness of the brush head while maintaining sufficient fitting length through optimized shaft geometry and support structure configuration.
2Reliability
If the head support shaft is located rearward to ensure fitting length, then the frictional resistance increases when the brush head tilts during brushing, but the stability of brush head action deteriorates
Solution Approach 1:
The patent repositions the head support shaft forward relative to the planting base, changing the spatial arrangement to optimize the moment arm geometry. This dimensional change reduces the moment arm length when the brush head tilts during brushing, thereby reducing the frictional resistance generated at the support shaft while maintaining adequate fitting length through optimized shaft design.
3Reliability
If the head support shaft is located rearward of the planting base, then the brush head size increases, but the cleaning performance on the back side of molar teeth deteriorates
Solution Approach 1:
The patent repositions the head support shaft forward of the planting base, changing the spatial configuration to reduce the front-rear thickness of the brush head. This dimensional optimization enables the brush head to access and clean hard-to-reach areas such as the back side of molar teeth, thereby improving cleaning performance while maintaining sufficient fitting length through optimized shaft geometry.
4Reliability
If the crank arms are provided at the rear surface of the rotation shaft to prevent brush head from coming off, then the size of the head part increases in the front-rear direction, but the compactness deteriorates
Solution Approach 1:
The patent integrates the coming-off prevention function directly into the crank arm structure by forming protrusions on the crank arms that engage with corresponding recesses in the support wall portion. This merging of functions eliminates the need for separate prevention mechanisms, thereby maintaining compact head part dimensions while ensuring reliable brush head retention.
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 design results in a more compact toothbrush head, improved operability, reduced frictional resistance, enhanced stability, and lower power consumption, allowing for effective cleaning of hard-to-reach areas with reduced energy use.
Implementation Method 1
the frictional resistance between a brush head and a neck body can be reduced
Implementation Method 2
a power transmission portion configured to transmit power from the driving portion to the brush head so that the brush head rotationally reciprocates
Implementation Method 3
the head-side conversion portion includes a swing lever to convert linear motion to rotational motion
Data Source
Figure 1
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AI summary
Provided is an electric toothbrush (10) in which a head portion (34) of a replaceable brush (30) has a reduced size in the front-rear direction so that operability of the head portion (34) in an oral cavity can be improved, and the frictional resistance between a brush head (40) and a neck body (32) and vibration of the brush head (40) are reduced so that stability of action of the brush head (40) can be improved and power consumption can be reduced. The brush head (40) is provided on the front surface at a distal-end-side part of a neck (31) of the replaceable brush (30). A fitting shaft portion (45) is provided on a planting base (42) of the brush head (40) so as to protrude rearward and penetrate through a support wall portion (37) of the neck (31). A shaft hole (41a) is formed at a rotation center of a brush head body (41) of the brush head (40) so as to extend frontward from a rear surface of the brush head body (41). The neck (31) has a head support shaft (49) mounted to the shaft hole (41a) so as to rotatably support the brush head (40). A front end of the head support shaft (49) is located frontward of a rear surface of the planting base (42), and power from the driving portion (13) is transmitted to a rear part of the fitting shaft portion (45).