Electric Toothbrush Motor Control for Smooth Intensity Adjustment
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Solution Overview
Problem
Existing electric toothbrushes lack the ability to smoothly and continuously adjust oscillation intensity without steps or jumping, limiting their effectiveness in teeth cleaning.
Innovation Solution
A personal care appliance with an electric motor and control circuit that varies the frequency and duty cycle of a voltage signal in response to user inputs, allowing for a substantially linear change in oscillation amplitude, enabling smooth intensity adjustments between different modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional electric toothbrushes are used with fixed oscillation modes, then the device structure is simple, but the oscillation intensity cannot be smoothly adjusted without steps or jumping
Solution Approach 1:
The patent implements dynamic oscillation intensity adjustment by continuously varying the oscillation amplitude from first to second intensity levels without discrete steps. The control circuit dynamically modifies the drive signal parameters (frequency and/or duty cycle) in real-time based on user input, enabling smooth transition between oscillation intensities rather than fixed discrete modes.
Solution Approach 2:
The patent changes the parameters of the oscillation signal (frequency and/or duty cycle) to control the oscillation amplitude. By varying these parameters continuously in response to user input through the user interface, the system achieves smooth intensity adjustment. The control circuit processes user input signals and translates them into corresponding parameter changes in the motor drive signal.
2Productivity
If oscillation amplitude is varied without linear rate of change control, then the control is simple, but the brushing experience is inconsistent
Solution Approach 1:
The patent implements a controlled feedback mechanism where the control circuit monitors the oscillation amplitude and adjusts the drive signal parameters accordingly to maintain a substantially linear rate of change. The system receives user input through the user interface and processes it through the control algorithm to ensure the oscillation amplitude transitions at a controlled linear rate, providing consistent brushing experience.
Solution Approach 2:
The patent pre-defines the substantially linear rate of change profile for oscillation amplitude variation. The control circuit is programmed with this rate of change characteristic, so when user input is received, the system automatically applies the predetermined linear transition profile rather than requiring real-time calculation, thus maintaining consistency while managing complexity.
3Ease of operation
If discrete oscillation modes are used, then the device is easier to manufacture, but the intensity adjustment has steps or jumping
Solution Approach 1:
The patent replaces mechanical discrete mode switching with electronic continuous control. Instead of using separate mechanical components for each oscillation mode, the system uses electronic control circuits that can continuously vary the drive signal parameters. This substitution of mechanical systems with electronic control enables smooth intensity transitions while maintaining manufacturing feasibility through integrated circuit design.
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
Enables smooth and continuous adjustment of oscillation intensity, enhancing teeth cleaning performance by ensuring a consistent and effective brushing experience.
Implementation Method 1
an electric motor configured to, in response to a voltage signal, oscillate the drive shaft in an oscillatory motion
Implementation Method 2
a pulse width modulation signal generator... the voltage signal having a frequency and a duty cycle, the control circuit configured to vary the frequency and the duty cycle of the voltage signal
Data Source
Figure 1
Figure 2
Figure 3A~4
AI summary
In one embodiment, a personal care appliance includes an electric motor having a drive shaft. In response to a voltage signal, the drive shaft is oscillated in an oscillatory motion having an oscillation amplitude. A control circuit includes, in operable cooperation, a user interface, a processor, a pulse width modulation signal generator, and a power source. The control circuit supplies the voltage signal to the electric motor, the voltage signal having a frequency and a duty cycle. The control circuit varies the frequency and the duty cycle of the voltage signal in response to an oscillation adjustment input received from the user interface so that the oscillation amplitude of the drive shaft is varied along a substantially linear rate of change profile relative to the frequency.