Driving method of sound wave motor of electric toothbrush and electric toothbrush

Abstract

The invention belongs to the field of motor control, and particularly relates to a driving method of a sound wave motor of an electric toothbrush and the electric toothbrush, the method comprises the steps that a preset signal is transmitted to the sound wave motor, a preset displacement characteristic is output, and the movement of the sound wave motor has a degree of freedom in one direction; the preset signal comprises a first sub-signal and a second sub-signal, the first sub-signal is a periodic waveform, the frequency of the second sub-signal changes with time, and the frequency of the second sub-signal is greater than that of the first sub-signal; under the influence of the first sub-signal, the sound wave motor generates a response of the first displacement characteristic; under the influence of the second sub-signal, the acoustic wave motor generates a response to a second displacement characteristic, and the second displacement characteristic generates pulses to massage the teeth or gingiva.

Description

Technical Field

[0001] The invention belongs to the field of motor control, and in particular relates to a driving method of an electric toothbrush sonic motor and an electric toothbrush. Background Art

[0002] In the prior art, an electric toothbrush often uses a sonic motor as a power source to drive the brush head and bristles to vibrate, thereby cleaning teeth. The rotor of the sonic motor vibrates near the equilibrium position, and its operating frequency is generally several hundred hertz, which is within the frequency range of normal human voice, so it is called a sonic motor, and the sonic motor is a single-phase AC motor.

[0003] Driving the sonic motor requires an AC power signal, usually a single-frequency or variable-frequency square wave or sine wave. The variable frequency means using single-frequency signals with different frequencies in different time periods, but still using a single-frequency signal in a single time period. For example, the signal in the first time period is 300 Hz, the signal in the second time period is 250 Hz, the signal in the third time period is 300 Hz, and the signal in the fourth time period is 250 Hz.

[0004] A single-frequency signal driving a sonic motor can only produce corresponding single-frequency vibration. Even if it is a variable frequency signal, since each individual time period is still a single-frequency signal, the generated vibration is also single-frequency, and the composite vibration of the sonic motor cannot be achieved.

[0005] Most of the motors used in electric toothbrushes in the prior art have only one degree of freedom in one direction. When a single-frequency driving signal is used to drive the motor of the electric toothbrush, it can only vibrate in a single vibration mode, so that the cleaning ability at any position in the oral cavity during brushing is certain. Since the directions of the various grooves of human teeth are different, the cleaning ability for areas that are prone to accumulation of food residues is limited.

[0006] For manual toothbrushing, the Chinese Stomatological Association recommends the horizontal vibration brushing method, also known as the Bass brushing method, which can focus on cleaning individual positions to obtain a clean oral environment. However, a good cleaning effect cannot be achieved in the single vibration mode of a unidirectional motor.

[0007] In the prior art, although some electric toothbrush products can achieve oscillating sweeping vibration, their corresponding structures are relatively complex and the cost is relatively high. Summary of the invention

[0008] The present invention is proposed based on the above-mentioned needs of the prior art. The technical problem to be solved by the present invention is to provide a driving method of an electric toothbrush sonic motor and an electric toothbrush so that the sonic motor can massage teeth and gums while improving the cleaning ability.

[0009] In order to solve the above problems, the technical solution provided by the present invention includes:

[0010] A driving method for a sonic motor of an electric toothbrush is provided, comprising: transmitting a preset signal to the sonic motor and outputting a preset displacement characteristic, wherein the movement of the sonic motor has a degree of freedom in one direction; the preset signal comprises a first sub-signal and a second sub-signal, wherein the first sub-signal is a periodic waveform, the frequency of the second sub-signal changes with time, and the frequency of the second sub-signal is greater than the frequency of the first sub-signal; under the influence of the first sub-signal, the sonic motor generates a response of a first displacement characteristic; under the influence of the second sub-signal, the sonic motor generates a response of a second displacement characteristic, and the second displacement characteristic generates pulses to massage teeth or gums.

[0011] The above-mentioned setting is used to realize the composite vibration of the sonic motor, that is, applying a composite signal at both ends of the sonic motor can drive the sonic motor to produce a preset characteristic displacement corresponding thereto, wherein the preset characteristic displacement includes a first characteristic displacement and a second characteristic displacement, and the two have different frequencies, thereby forming a composite swing vibration. With the aid of the swing vibration, the teeth can be further cleaned to keep the oral cavity clean. In one degree of freedom, when the motor moves from a certain position along one of the directions of the degree of freedom, it is accompanied by multiple vibrations along the direction, that is, composite vibration is realized by a composite drive signal, so that the teeth are well cleaned. The high-frequency signal is set as a variable frequency signal to form an action with different sweep vibration degrees, and the sweep vibration brought by the low-frequency signal is superimposed at the same time, which can produce an effect similar to massage, so as to prevent damage to the gums caused by excessive force while cleaning the teeth.

[0012] Preferably, the first sub-signal is expressed as: U2(t)=V2sinω2t, wherein V2 represents the peak value of the first sub-signal, and ω2 represents the angular frequency of the first sub-signal; the corresponding first displacement characteristic is expressed as: X1(t)=A1sinω1t, X1(t) is the displacement function of the acoustic wave motor with the equilibrium position as the origin under the first sub-signal, and A1 is the maximum displacement relative to the origin under the first sub-signal; the second sub-signal is expressed as: U2(t)=V2sinω2(t)t, wherein V2 represents the peak value of the second sub-signal, and ω2 represents the angular frequency of the second sub-signal; the corresponding second displacement characteristic is expressed as: X2(t)=A2sinω2(t)t, X2(t) is the displacement function of the acoustic wave motor with the equilibrium position as the origin under the second sub-signal, and A2 is the maximum displacement relative to the origin under the second sub-signal.

[0013] Theoretically, any periodic waveform can be decomposed into the superposition of several sine waves of different periods, that is, any periodic waveform can be formed by superposition of several sine waves of different periods, that is, the above setting can realize the superposition of multiple waveforms of different frequencies, thereby forming the composite vibration of the acoustic wave motor, and can also realize swing vibration. In addition, the sine wave does not generate high-frequency components in the frequency domain, so as to effectively avoid high-frequency noise.

[0014] Preferably, the frequency of the second sub-signal varies continuously over time.

[0015] Preferably, the frequency of the second sub-signal is expressed as: ω2(t)=απ+βπsinω3t, where ω2(t) is the angular frequency, a function that changes continuously with time and is periodic, and the period is The average value of ω2(t) is απ, the maximum value is (α+β)π, and the minimum value is (α-β)π.

[0016] Preferably, the frequency of the second sub-signal changes in a step-by-step manner over time.

[0017] Preferably, the frequency of the second sub-signal is expressed as: ω2(t) is a function that changes step by step with time, and the value of ω2(t) switches between aπ and bπ.

[0018] Preferably, an adaptation duty cycle of an adaptation formula wave is obtained according to a power supply voltage and a preset signal in a digital signal system; the preset signal is expressed as U(t)=V1sinω1t+V2sinω2(t)t, V1 represents a peak value of a first sub-signal, ω1 represents an angular frequency of the first sub-signal, V2 represents a peak value of a second sub-signal, ω2 represents an angular frequency of the second sub-signal, the power supply voltage is V0, and V0≥V2+V2 is satisfied; the adaptation duty cycle is expressed as: Wherein, k[n] represents the nth adaptation duty cycle, Δt represents the period of the adaptation waveform, and Δt≤0.05ms.

[0019] Through the above setting, digital signals can be input at both ends of the sonic motor to realize multi-frequency composite swing vibration, which can ensure that the effect produced by the sonic motor is consistent with the effect produced by the sonic motor under the preset AC power signal represented by the simulated sine wave signal when the adaptive square wave signal is input. And Δt≤0.05ms. This setting makes the digital signal close to the analog signal while making the introduced additional vibration greater than 20kHz. The sound generated by the introduced frequency component belongs to ultrasonic wave, which cannot be heard by human ears, and noise will be effectively avoided.

[0020] Preferably, when the period of the adaptation waveform and the period of the first power signal satisfy Where Δt represents the period of the adaptive waveform, and the period of the adaptive waveform and the period of the second power signal satisfy When , the adaptation duty cycle is expressed as:

[0021] Preferably, the preset signal is expressed as U(t)=U2(t)+U2(t)+…+U m (t), where U1(t) = V1sinω1t, V1 represents the peak value of the first sub-signal, ω1 represents the angular frequency of the first sub-signal; U2(t) = V2sinω2(t)t, V2 represents the peak value of the second sub-signal, ω2(t) represents the angular frequency of the second sub-signal, and ω2(t) is the maximum angular frequency in the m sub-systems; U m (t) = V m sinω m (t)t,U m (t) represents the mth sub-signal, V m represents the peak value of the mth sub-signal, ω m (t) represents the angular frequency of the mth sub-signal, and the supply voltage V0 satisfies V0≥V1+V2+…+V m ; The adapted duty cycle is expressed as: Wherein, k[n] represents the nth adaptation duty cycle, Δt represents the period of the adaptation waveform, and Δt≤0.05ms.

[0022] Also provided is an electric toothbrush, comprising: a brush head for cleaning teeth; a motor output shaft connected to the sonic motor to transmit the response of the sonic motor; a brush handle connected to the brush head and the motor output shaft, respectively, to transmit the response of the sonic motor to the brush head; and a controller electrically connected to the sonic motor, the controller driving the motor by any of the above-mentioned driving methods for the sonic motor of an electric toothbrush.

[0023] The above-mentioned setting drives the brush head to perform a composite frequency swing vibration, so as to better play the role of cleaning teeth. Compared with a single vibration mode, it can clean all angles of the teeth, thereby improving the user experience. In other words, when the brush head is driven by the first sub-signal, it is also driven by the second sub-signal, so that the brush head has a first characteristic displacement in a certain direction and a second characteristic displacement at the same time, thereby achieving a conforming vibration mode and achieving a better cleaning effect. In addition, since the frequency of the second sub-signal changes with time, it forms movements with different sweep vibration degrees, and the sweep vibration brought by the superimposed low-frequency signal can produce an effect similar to massage, so as to prevent damage to the gums caused by excessive force while cleaning the teeth.

[0024] Compared with the prior art, the present invention applies multiple AC power signals with different frequencies at both ends of the sonic motor to form a preset AC power signal. At this time, the vibration of the sonic motor will correspond to the preset AC power signal applied, that is, it can generate a composite frequency swing vibration. The driving method of the electric toothbrush motor is applied to the electric toothbrush, so that the sonic motor can drive the brush head and the bristles on the brush head to vibrate at a composite frequency, so that the teeth can be better cleaned. Specifically, the following vibration mode will be generated. When the brush head moves to the leftmost end within the swingable range, it swings several times with a small amplitude, that is, the vibration of the brush head driven by the motor meets the preset displacement characteristics; similarly, when the brush head moves to the rightmost end within the swingable range, it also swings several times with a small amplitude, and the vibration of the brush head driven by the motor meets the preset displacement characteristics. Based on the above swing mode, the electric toothbrush can better clean the teeth and ensure the cleanliness of the inside of the oral cavity. In addition, for other motors, after upgrading or improving the method of controlling the motor, the swing sweep vibration can also be realized, saving user costs and promoting healthy brushing methods. In addition, one of the sub-signals forming the preset signal is a variable frequency signal. The vibration displacement generated under the drive of the variable frequency signal is different. At the same time, the sweeping vibration brought by the superimposed low-frequency signal can produce an effect similar to massage, so as to prevent damage to the gums caused by excessive force while cleaning the teeth. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this specification. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0026] Figure 1 This is a schematic diagram of angular frequency fluctuation corresponding to the second sub-signal in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of a preset signal in an embodiment of the present application;

[0028] Figure 3 is a schematic diagram of angular frequency fluctuation corresponding to another second sub-signal in an embodiment of the present application;

[0029] Figure 4 This is another schematic diagram of a preset signal in an embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connected" should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or an integral connection, which can be a mechanical connection, or an electrical connection, which can be a direct connection, or can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] The terms "top", "bottom", "above", "lower", and "on" used throughout the description are relative to the relative positions of components of a device, such as the relative positions of the top and bottom substrates within a device. It is understood that devices are multifunctional regardless of their orientation in space.

[0033] To facilitate understanding of the embodiments of the present application, further explanation will be given below with reference to specific embodiments in conjunction with the accompanying drawings. The embodiments do not constitute a limitation on the embodiments of the present application.

[0034] Example 1

[0035] This embodiment provides a method for driving a sonic motor of an electric toothbrush.

[0036] When the acoustic wave motor generates vibration based on the AC power signal it receives, the displacement characteristics of the vibration and the AC power signal are basically positively correlated. Therefore, based on the above relationship, when an AC power signal with a frequency of f is added to both ends of the acoustic wave motor, the acoustic wave motor will correspondingly generate vibration with a frequency of f.

[0037] The AC power signal can be a square wave, a sine wave, a triangle wave or other waveforms. Based on the above principle, when the AC power signal is a square wave, the displacement near the equilibrium position when the motor vibrates is also close to the square wave function; when the AC power signal is a sine wave, the displacement near the equilibrium position when the motor vibrates is also close to the sine function.

[0038] By utilizing the relationship between the AC power signal and the acoustic wave motor, a composite AC power signal can be applied to both ends of the acoustic wave motor to make the motor vibrate in a manner having a displacement characteristic corresponding to the composite function.

[0039] That is to say, a preset AC power signal is applied to both ends of the acoustic wave motor to obtain the preset displacement characteristics of the acoustic wave motor. The waveform of the preset AC power signal is a waveform formed by a composite function, that is, the preset AC power signal is formed by superposition of multiple AC power signals of different frequencies, and the waveform of the preset displacement characteristics is also a waveform formed by a composite function.

[0040] Furthermore, when the superimposed signal includes a variable frequency drive signal, pulses are usually generated on the motor, and the pulses can have a massage effect.

[0041] The preset signal is composed of a first sub-signal and a second sub-signal, which is expressed as: U(t)=U1(t)+U2(t), wherein U(t) represents the preset signal, U1(t) is the first sub-signal, and U2(t) is the second sub-signal. The first sub-signal is a periodic waveform, and the frequency of the second sub-signal changes with time. When only the first sub-signal is input to the sonic wave motor, the first displacement characteristic of the sonic wave motor is X1(t); when only the first sub-signal is input to the sonic wave motor, the second displacement characteristic of the sonic wave motor is X2(t); when the preset signal is input to the sonic wave motor, the displacement of the sonic wave motor is X(t)=X1(t)+X2(t).

[0042] Furthermore, since the composite frequency vibration of the acoustic wave motor can be not only the vibration formed by the superposition of two frequencies, but also the vibration formed by the superposition of three frequencies or four frequencies, the preset signal is expressed as U(t)=U1(t)+U2(t)+…+U m (t), the corresponding preset displacement characteristic is expressed as: X(t) = X1(t) + X2(t) + ... + X m (t). Where U m (t) is the mth sub-signal, X m (t) is the displacement characteristic corresponding to the mth sub-signal.

[0043] When the preset AC power signal is an analog signal, in theory, any periodic waveform can be decomposed into the superposition of several sine waves of different periods, that is, any periodic waveform can be formed by superposition of several sine waves of different periods, that is, the superposition of multiple waveforms of different frequencies can be achieved through the above setting, thereby forming a composite vibration of the acoustic wave motor, and also realizing swing vibration. In addition, no high-frequency component is generated in the frequency domain of the sine wave, so as to effectively avoid high-frequency noise.

[0044] Therefore, the above U1(t)=V1sinω1t, U1(t) represents the first sub-signal, V1 represents the peak value of the first sub-signal, and ω1 represents the angular frequency of the first sub-signal; U2(t)=V2sinω2(t)t, U2(t) represents the second sub-signal, V2 represents the peak value of the second sub-signal, and ω2(t) represents the angular frequency of the second sub-signal; Um (t) = V m sinω m (t)t, where U m (t) represents the mth sub-signal, V m represents the peak value of the mth sub-signal, ω m (t) represents the angular frequency of the mth sub-signal. The corresponding X1(t) = A1sinω1t, X1(t) is the displacement function of the acoustic wave motor with the equilibrium position as the origin under the first sub-signal, and A1 is the maximum displacement with the equilibrium position as the origin under the first sub-signal; X2(t) = A2sinω2(t)t, X2(t) is the displacement function of the acoustic wave motor with the equilibrium position as the origin under the second sub-signal, and A2 is the maximum displacement with the equilibrium position as the origin under the second sub-signal; where X m (t) = A m sinω m (t)t,X m (t) is the displacement function of the acoustic wave motor with the equilibrium position as the origin under the mth sub-signal, A m is the maximum value of the displacement with the equilibrium position as the origin under the mth sub-signal.

[0045] Preferably, when the preset signal includes only the first sub-signal and the second sub-signal, it is expressed as U(t)=V1sinω1t+V2sinω2(t)t. Since the displacement characteristic of the acoustic wave motor vibration is basically positively correlated with the applied AC power, the corresponding preset displacement characteristic is expressed as: X(t)=A1sinω1t+A2sinω2(t)t. Among them, ω1=2πf1, f1 is the frequency of the first sub-signal, ω2(t)=2πf2(t), f2(t) is the frequency of the second sub-signal, and the frequency of the second sub-signal is greater than the frequency of the first sub-signal. V1 and V2 can be combined in any proportion, and the desired vibration effect can be produced by adjusting the numerical value.

[0046] In some cases there are: This is because the sonic motor has different frequency responses to different frequencies, that is, some frequencies can produce larger amplitude vibrations under a smaller voltage excitation; while other frequencies can only produce smaller amplitude vibrations under a larger voltage.

[0047] The frequency of the second sub-signal changes with time. The frequency may change continuously with time or change gradually with time.

[0048] When the frequency of the second sub-signal changes continuously with time, the angular frequency of the second sub-signal is expressed as ω2(t)=απ+βπsinω3t, where ω2(t) changes continuously with time and is a periodic function with a period of The average value of ω2(t) is απ, the maximum value is (α+β)π, and the minimum value is (α-β)π.

[0049] For example, ω2(t)=520π+60πsinω3t, the average value of ω2(t) is 520π, the maximum value is 580π, and the minimum value is 460π. If converted into frequency, it is equivalent to an average value of 260Hz, a maximum value of 290Hz, and a minimum value of 230Hz.

[0050] like Figure 1 and Figure 2 As shown, when the first sub-signal is U1(t)=3sin10πt and the second sub-signal is U2(t)=2sin(520π+15πsin20πt)t, the preset signal is expressed as: U(t)=3sin10πt+2sin(520π+15πsin20πt)t.

[0051] When the frequency of the second signal changes in stages over time, the angular frequency of the second sub-signal is expressed as: ω2(t) is a function that changes stepwise with time, and its value switches between aπ and bπ.

[0052] For example, In the above formula, ω2(t) is a function that changes stepwise over time. The value of ω2(t) switches between 520π and 500π every 0.1 seconds. Converted to frequency, it is equivalent to 260Hz and 250Hz.

[0053] like Figure 3 and Figure 4 As shown, when the first sub-signal is U1(t)=3sin10πt, the second sub-signal is When , the preset signal is expressed as:

[0054] That is, when the sonic wave motor moves along the first direction of freedom, multiple swinging vibrations between the first direction and the second direction will be generated at the same time, that is, gradually approaching the boundary position of the first direction by swinging; when the sonic wave motor moves along the second direction of freedom, multiple swinging vibrations of the first direction and the second direction brackets will also be generated at the same time, gradually approaching the boundary position of the second direction by swinging vibrations.

[0055] When narrow pulses with equal impulses but different shapes are added to a link with inertia, the effect is basically the same; impulse is the area of ​​the narrow pulse, and the effect is basically the same means that the output waveform of the link is basically the same. If the input waveforms are analyzed by Fourier transform, their low frequency bands are very close, with only slight differences in high frequencies. Since the acoustic wave motor itself is an inductive device, when the voltage at both ends of the motor suddenly changes, the current of the motor will not suddenly change, but will rise or fall according to the voltage with its own inductance as the gradient, so the current of the motor has inertia to the external voltage excitation, which meets the conditions of the area equivalence principle.

[0056] When the preset AC power signal is a digital signal, the area equivalence principle can be used, that is, the principle that when narrow pulses with equal impulses but different shapes are added to a link with inertia, the effect is basically the same. Here, the link with inertia refers to the acoustic wave motor, which is an inductive device. When stimulated by a voltage signal, its current has inertia. Digital signals only output two states: low / high. If an analog signal is divided into a large number of small segments (i.e., narrow pulses) on the time axis, and each small segment of digital signal uses a square wave to approximate the corresponding analog signal, as long as the digital signal and the analog signal in the small segment have the same integral over time (i.e., the impulse is equal but the shape is different), the effects produced by the two are basically the same.

[0057] The adapted duty cycle of the adapted formula wave is obtained according to the power supply voltage and the preset AC power signal in the digital signal system.

[0058] For the nth segment, that is, the time period from (n-1)Δt to nΔt, n = 1, 2, 3, ..., the integral of U(t) over time is U[n]:

[0059]

[0060] In each time period Δt, the digital signal uses a square wave pulse to generate the corresponding impulse. Let the adaptation duty cycle of the nth time period be k[n], then the integral of the digital signal over time in this time period is:

[0061] U′[n]=k[n]V0Δt

[0062] The area equivalence principle requires that U[n] = U'[n], then

[0063]

[0064] For example, for the analog signal U(t)=V1sinω1t+V2sinω2(t)t, the signal is divided into small segments on the time axis, and the length of each segment is Δt. And Δt≤0.05ms. This setting makes the digital signal close to the analog signal, while making the introduced additional vibration greater than 20kHz. The sound generated by the introduced frequency component belongs to ultrasonic wave, which cannot be heard by human ears, and noise will be effectively avoided.

[0065] For the nth segment, let the integral of U(t) over time be U[n], then

[0066]

[0067] Assume that the power supply voltage of the digital signal system is V0. In order to make the maximum value generated by the digital signal correspond to the maximum value generated by the analog signal so as to achieve equal impulses of the two, set V0≥V1+V2.

[0068] According to the area equivalence principle, we know that:

[0069]

[0070] That is to say, a digital square wave signal with a supply voltage of V0 and a period of Δt has a duty cycle of nth period satisfying When , the vibration effect produced on the sonic motor is basically the same as U(t)=V1sinω1t+V2sinω2(t)t.

[0071] The duty cycle refers to the proportion of the power-on time to the total time in a pulse cycle. But in fact, the integral of the sine signal will have a negative value, that is, k[n] may be positive or negative. When k[n] is a positive number, it means that the sonic motor is powered in the forward direction when powered on; when k[n] is a negative number, it means that the sonic motor is powered in the reverse direction when powered on.

[0072] The sonic motor is a single-phase motor with a pair of lead wires, one of which is marked as A and the other as B. If k[n]>0 means that power is supplied from A to B, then when k[n]<0, power is supplied from B to A. For example, k[n]=0.4 means that the motor is supplied with power from A to B with voltage V0 for 0.4Δt, and no power is supplied for the remaining 0.6Δt. k[n]=-0.7 means that the motor is supplied with power from B to A with voltage V0 for 0.7Δt, and no power is supplied for the remaining 0.3Δt.

[0073] When the period of the square wave and the period of the first sub-signal meet Where Δt represents the period of the adaptive wave, and the period of the adaptive wave and the period of the second sub-signal satisfy When , the duty cycle is expressed as:

[0074]

[0075] In addition, the above method is not only for motors that can only vibrate in a single degree of freedom, but can also be applied to motors that can vibrate in multiple degrees of freedom. It can combine more vibration conditions that are suitable for different oral conditions and brushing environments, thereby forming a corresponding cleaning effect. In addition, if the effects of multiple degrees of freedom can be achieved in one degree of freedom, other vibration settings can be made for motors that vibrate in other degrees of freedom to effectively save and utilize resources. Furthermore, frequency conversion of high-frequency signals can generate pulses on the electrodes, which can have a massage effect.

[0076] Example 2

[0077] This embodiment provides an electric toothbrush.

[0078] An electric toothbrush includes a brush head, a brush handle, a motor assembly and a controller.

[0079] The brush head is provided with a cleaning part for cleaning teeth, and the cleaning part can be bristles.

[0080] The motor assembly comprises a sonic motor and a motor output shaft, wherein the sonic motor is arranged inside the electric toothbrush, one end of the motor output shaft is connected to the sonic motor, and the other end is connected to the brush head.

[0081] A controller is electrically connected to the sonic wave motor, and the controller controls the sonic wave motor to drive the sonic wave motor to work through the driving method of the electric toothbrush motor in Example 1.

[0082] Taking the example that both the first sub-signal and the second sub-signal are input as sine waves, the brush head produces corresponding left and right swings. In the process of the brush head swinging to the left to the leftmost end, this process corresponds to the displacement of the brush head driven by the first sub-signal; in this process, multiple left and right swings are performed simultaneously, corresponding to the displacement driven by the second sub-signal; similarly, in the process of the brush head swinging to the right to the rightmost end, multiple left and right swings are performed simultaneously, and the above process is repeated continuously, thereby effectively cleaning the teeth.

[0083] Common electric toothbrushes usually vibrate at an overall frequency when working, which makes it difficult to achieve good cleaning. The driving method of the electric toothbrush motor allows the electric toothbrush to have a variety of different oscillation frequencies to enhance the cleaning effect on teeth. In addition, the above setting can make the sonic motor no longer emit a sharp sound when brushing teeth with an electric toothbrush, so as to improve the user experience. When the user experience is good, the user will inadvertently extend the use time, thereby achieving a better tooth cleaning effect.

[0084] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation method of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for driving an electric toothbrush sonic motor, characterized in that: include: Transmitting a preset signal to the sonic motor to output a preset displacement characteristic, wherein the movement of the sonic motor has a degree of freedom in one direction; The preset signal includes a first sub-signal and a second sub-signal, wherein the first sub-signal is a periodic waveform, the frequency of the second sub-signal changes with time, and the frequency of the second sub-signal is greater than the frequency of the first sub-signal; Under the influence of the first sub-signal, the acoustic wave motor generates a response with a first displacement characteristic; Under the influence of the second sub-signal, the sonic motor responds with a second displacement characteristic, which generates pulses to massage the teeth or gums.

2. The driving method of the electric toothbrush sonic motor according to claim 1, characterized in that: The first sub-signal is expressed as: U1(t)=V1sinω1t, where V1 represents the peak value of the first sub-signal, and ω1 represents the angular frequency of the first sub-signal; The corresponding first displacement characteristic is expressed as: X1(t)=A1sinω1t, X1(t) is the displacement function of the acoustic wave motor under the first sub-signal with the equilibrium position as the origin, and A1 is the maximum displacement relative to the origin under the first sub-signal; The second sub-signal is expressed as: U2(t)=V2sinω2(t)t, where V2 represents the peak value of the second sub-signal, and ω2 represents the angular frequency of the second sub-signal; The corresponding second displacement characteristic is expressed as: X2(t)=A2sinω2(t)t, where X2(t) is the displacement function of the acoustic wave motor with the equilibrium position as the origin under the second sub-signal, and A2 is the maximum displacement relative to the origin under the second sub-signal.

3. The driving method of the electric toothbrush sonic motor according to claim 1, characterized in that: The frequency of the second sub-signal varies continuously over time.

4. The driving method of the electric toothbrush sonic motor according to claim 3, characterized in that: The frequency of the second sub-signal is expressed as: ω2(t)=απ+βπsinω3t ω2(t) is the angular frequency, which changes continuously with time and is a periodic function with a period of The average value of ω2(t) is απ, the maximum value is (α+β)π, and the minimum value is (α-β)π.

5. The driving method of the electric toothbrush sonic motor according to claim 1, characterized in that: The frequency of the second sub-signal changes step by step over time.

6. The driving method of the electric toothbrush sonic motor according to claim 5, characterized in that: The frequency of the second sub-signal is expressed as: ω2(t) is a function that changes stepwise over time, and the value of ω2(t) switches between aπ and bπ.

7. The driving method of the electric toothbrush sonic motor according to claim 1, characterized in that: Obtaining an adapted duty cycle of an adapted formula wave according to a power supply voltage and a preset signal in a digital signal system; The preset signal is expressed as U(t)=V1sinω1t+V2sinω2(t)t, V1 represents the peak value of the first sub-signal, ω1 represents the angular frequency of the first sub-signal, V2 represents the peak value of the second sub-signal, ω2 represents the angular frequency of the second sub-signal, and the supply voltage is V0, and V0≥V1+V2 is satisfied; The adapted duty cycle is expressed as: Wherein, k[n] represents the nth adaptation duty cycle, Δt represents the period of the adaptation waveform, and Δt≤0.05ms.

8. The driving method of the electric toothbrush sonic motor according to claim 1, characterized in that: When the period of the adaptive waveform and the period of the first power signal meet Where Δt represents the period of the adaptive waveform, and the period of the adaptive waveform and the period of the second power signal satisfy When , the adaptation duty cycle is expressed as:

9. The driving method of the electric toothbrush sonic motor according to claim 7, characterized in that: The preset signal is expressed as U(t)=U1(t)+U2(t)+…+U m (t), where U1(t) = V1sinω1t, V1 represents the peak value of the first sub-signal, ω1 represents the angular frequency of the first sub-signal; U2(t) = V2sinω2(t)t, V2 represents the peak value of the second sub-signal, ω2(t) represents the angular frequency of the second sub-signal; U m (t) = V m sinω m (t)t,U m (t) represents the mth sub-signal, V m represents the peak value of the mth sub-signal, ω m (t) represents the angular frequency of the mth sub-signal, and the supply voltage V0 satisfies V0≥V1+V2+…+V m ; The adapted duty cycle is expressed as: Wherein, k[n] represents the nth adaptation duty cycle, Δt represents the period of the adaptation waveform, and Δt≤0.05ms.

10. An electric toothbrush, characterized in that: include: A brush head for cleaning teeth; A motor output shaft is connected to the sonic motor to transmit the response of the sonic motor; A brush handle, connected to the brush head and the motor output shaft, respectively, to transmit the response of the sonic motor to the brush head; A controller is electrically connected to the sonic wave motor, and the controller drives the motor by the driving method of the electric toothbrush sonic wave motor according to any one of claims 1-9.

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