Ultrasonic vibration device and ultrasonic cleaning device

Abstract

To achieve low power consumption.SOLUTION: An ultrasonic vibration device 100 includes an ultrasonic vibrator 11A, and a driving part 12. When receiving an oscillation signal S1 having a predetermined oscillation frequency fc, the ultrasonic vibrator 11A ultrasonically vibrates at an oscillation frequency fc. The driving part 12 outputs the oscillation signal S1, and drives the ultrasonic vibrator 11A. The driving part 12 and the ultrasonic vibrator 11A contain capacitor components C0 and C1 and an inductance component L1, and impedance characteristics having a resonance frequency fa and an antiresonance frequency fb on the basis of a relation between the capacitor components C0 and C1 and the inductance component L1. The oscillation frequency fc is set to be between the resonance frequency fa and the antiresonance frequency fb, and be closer to the side of the antiresonance frequency fb than a middle frequency between the resonance frequency fa and the antiresonance frequency fb.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an ultrasonic vibration device and an ultrasonic cleaning device. [Background technology]

[0002] The ultrasonic treatment device of Patent Document 1 comprises a device body having an ultrasonic transducer and an ultrasonic transmitter that transmits ultrasonic waves generated by the ultrasonic transducer, a detection means that detects the impedance or Q value of the device body at resonance, and a control means that controls the power supplied to the ultrasonic transducer using a signal from the detection means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent application No. 63-212342 Summary of the Invention [Problem to be solved by the invention]

[0004] The ultrasonic transducer used in the ultrasonic treatment device of Patent Document 1 is most likely to resonate at the resonant frequency. Therefore, the oscillation frequency of the ultrasonic transducer is generally set based on the resonant frequency. On the other hand, if the oscillation frequency of the ultrasonic transducer is set based on the resonant frequency, the current flowing through the ultrasonic treatment device increases, and the power consumption of the ultrasonic treatment device increases.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic vibration device and an ultrasonic cleaning device that are capable of keeping power consumption low. [Means for solving the problem]

[0006] The ultrasonic vibration device according to the present invention includes an ultrasonic transducer and a driving unit. When the ultrasonic transducer receives an oscillation signal having a predetermined oscillation frequency, it ultrasonically vibrates at the oscillation frequency. The driving unit outputs the oscillation signal to drive the ultrasonic transducer. The driving unit and the ultrasonic transducer include a capacitance component and an inductance component, and an impedance characteristic having a resonant frequency and an anti-resonant frequency based on the relationship between the capacitance component and the inductance component. The oscillation frequency is set between the resonant frequency and the anti-resonant frequency and on the anti-resonant frequency side of the intermediate frequency between the resonant frequency and the anti-resonant frequency. Effect of the Invention

[0007] According to the present invention, it is possible to keep power consumption low. [Brief description of the drawings]

[0008] [Figure 1] 1 is an external view of an ultrasonic cleaner according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a functional block diagram of the ultrasonic cleaner according to the present embodiment. [Diagram 3] FIG. 2 is a diagram showing an equivalent circuit of the ultrasonic vibration device according to the embodiment. [Figure 4] FIG. 4 is a diagram showing frequency characteristics of impedance in the ultrasonic vibration device according to the present embodiment. [Diagram 5] 4 is a flowchart showing a method for setting an oscillation frequency in an ultrasonic vibration device. [Figure 6] 1 is a graph showing changes over time in the current flowing through an ultrasonic transducer. [Figure 7] FIG. 5 is an enlarged view of the impedance frequency characteristics shown in FIG. 4 in the vicinity of an anti-resonance frequency. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0010] The configuration of an ultrasonic cleaner 1 according to this embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is an external view of the ultrasonic cleaner 1 according to this embodiment. Fig. 2 is a functional block diagram of the ultrasonic cleaner 1 according to this embodiment.

[0011] The ultrasonic cleaner 1 includes a main body cover 10A, a push button switch 10C, an ultrasonic horn 11, a drive unit 12, and a temperature sensor 13. The ultrasonic cleaner 1 is an example of an ultrasonic cleaning device.

[0012] The body cover 10A is a cylindrical member that covers the ultrasonic horn 11, the driving unit 12, and the temperature sensor 13. A bottom cover 10B is attached to one axial side of the body cover 10A. In this embodiment, a push button switch 10C is provided in the center of the bottom cover 10B. The push button switch 10C is, for example, a power switch that switches the driving unit 12 between driving and stopping.

[0013] The ultrasonic horn 11 is ultrasonically vibrated. Specifically, the ultrasonic horn 11 includes an ultrasonic transducer 11A and a horn body 11B. When the ultrasonic transducer 11A receives an oscillation signal S1, which is an AC voltage having a predetermined frequency, the ultrasonic transducer 11A is ultrasonically vibrated at the frequency of the oscillation signal S1. The horn body 11B is, for example, a flat metal member. Typically, the horn body 11B is made of iron, titanium, or aluminum. The horn body 11B is attached to the ultrasonic transducer 11A. As shown in FIG. 1, the horn body 11B is disposed on the body cover 10A so that a portion of the horn body 11B is exposed from the body cover 10A. The horn body 11B vibrates in accordance with the vibration of the ultrasonic transducer 11A.

[0014] In other words, the ultrasonic vibration of the ultrasonic vibrator 11A is transmitted through the horn body 11B to a medium such as air or water, or to an object to be cleaned by the ultrasonic cleaner 1. That is, the horn body 11B transmits the ultrasonic vibration of the ultrasonic vibrator 11A to the outside of the body cover 10A. The horn body 11B is an example of a transmission section.

[0015] The driving unit 12 outputs an oscillation signal S1 to drive the ultrasonic transducer 11A. For example, the driving unit 12 includes a driving circuit (not shown), a battery (not shown) that supplies power to the driving circuit, and a signal output unit 121. The driving circuit may include circuit elements such as resistors, capacitors, coils, and a power supply, a processor such as a CPU (Central Processing Unit), a storage device such as a memory that stores data, computer programs, and the like, and a circuit board on which the circuit elements, the processor, the storage device, and the like are mounted.

[0016] As an example, a processor functioning as a signal output unit 121 is implemented in the drive circuit of the drive unit 12. Specifically, when the processor of the drive unit 12 executes a computer program, the processor functions as the signal output unit 121. The signal output unit 121 outputs an oscillation signal S1 having a preset predetermined frequency to the ultrasonic transducer 11A. Hereinafter, the oscillation signal S1 and the predetermined frequency of the ultrasonic transducer 11A will be referred to as an oscillation frequency. In this embodiment, the ultrasonic transducer 11A and the drive unit 12 constitute an ultrasonic vibration device 100.

[0017] The signal output unit 121 is not limited to a processor, and may be an analog circuit or a digital circuit capable of outputting an AC voltage with a variable frequency.

[0018] Next, the setting of the oscillation frequency will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing an equivalent circuit T1 of the ultrasonic vibration device 100 according to this embodiment. Fig. 4 is a diagram showing the frequency characteristic of the impedance Z in the ultrasonic vibration device 100 according to this embodiment. Hereinafter, the frequency characteristic of the impedance Z may be simply referred to as the impedance characteristic.

[0019] In this embodiment, the ultrasonic transducer 11A and the driving unit 12 include a capacitance component and an inductance component. Therefore, the circuit configuration of the ultrasonic vibration device 100 can be expressed by an equivalent circuit including a capacitance component and an inductance component, as shown in FIG.

[0020] 3, the equivalent circuit T1 of the ultrasonic vibration device 100 is expressed by a parallel connection of a series connection of an inductance component L1, a capacitor component C1, and a resistance component R1, and a capacitor component C0. Therefore, the equivalent circuit T1 has a resonant frequency fa and an anti-resonant frequency fb based on the relationship between the capacitor component and the inductance component.

[0021] The resonance frequency fa is calculated by the following formula (1) using an inductance component L1, capacitance components C1 and C0, and a resistance component R1.

[0022]

number

[0023] The anti-resonant frequency fb is calculated by the following formula (2) using an inductance component L1, capacitance components C1 and C0, and a resistance component R1.

[0024]

number

[0025] As shown in Fig. 4, the impedance Z in the equivalent circuit T1 is minimum (local minimum) at the resonant frequency fa, while it is maximum (local maximum) at the anti-resonant frequency fb. In other words, the resonant frequency fa is a frequency at which current easily flows through the circuit, and is a frequency suitable for driving the circuit at a low voltage. In contrast, the anti-resonant frequency fb is a frequency at which current does not easily flow through the circuit, and while a high voltage is required to drive the circuit, it is a frequency at which power consumption can be kept low. In the example of Fig. 4, the resonant frequency fa is about 38 [kHz], and the anti-resonant frequency fb is about 39 [kHz].

[0026] Here, the ultrasonic transducer 11A can generate ultrasonic vibrations at frequencies greater than the resonance frequency fa and less than the anti-resonance frequency fb. In other words, the ultrasonic transducer 11A does not generate normal ultrasonic vibrations at frequencies less than the resonance frequency fa or greater than the anti-resonance frequency fb. That is, in the ultrasonic vibration device 100, the oscillation frequency is set to a frequency greater than the resonance frequency fa and less than the anti-resonance frequency fb shown in FIG. 4.

[0027] Next, a method for setting the oscillation frequency in the ultrasonic vibration device 100 will be described with reference to Fig. 5. Fig. 5 is a flowchart showing a method for setting the oscillation frequency in the ultrasonic vibration device 100.

[0028] In this embodiment, the inductance component L1, the capacitor components C1 and C0, and the resistance component R1 in the ultrasonic vibration device 100 have individual differences. That is, the inductance component L1, the capacitor components C1 and C0, and the resistance component R1 in the ultrasonic vibration device 100 differ for each individual. For this reason, in the ultrasonic vibration device 100, the oscillation frequency is set individually for each individual during manufacturing.

[0029] In detail, first, for example, a signal generator other than the signal output unit 121 is electrically connected to the ultrasonic vibration device 100, and an oscillation signal S2, which is an AC voltage having a predetermined frequency output from the signal generator, is input to the ultrasonic vibration device 100 (step S11). At this time, the frequency of the oscillation signal S2 is set to a frequency assumed to be between the resonance frequency fa and the anti-resonance frequency fb.

[0030] Next, with the oscillation signal S2 being input to the ultrasonic vibration device 100, the current J1 flowing through the ultrasonic transducer 11A is measured (step S12).

[0031] Next, the measured current J1 is compared with a threshold min (step S13). The threshold min corresponds to the current when an oscillation signal having a frequency just below the anti-resonance frequency fb flows through the ultrasonic transducer 11A. If the current J1 is equal to or greater than the threshold min (No in step S13), the frequency of the oscillation signal S2 is increased (step S15). With the oscillation signal S2 with the increased frequency input to the ultrasonic vibration device 100, the current J1 flowing through the ultrasonic transducer 11A is measured (step S12).

[0032] On the other hand, if the current J1 is smaller than the threshold min (Yes in step S13), the frequency of the oscillation signal S2 is lowered by fs [Hz] and set to fc [Hz] (step S14). Next, the frequency of the oscillation signal S1 output from the signal output unit 121 is set to fc [Hz] (step S16).

[0033] Here, the relationship between temperature change and anti-resonance frequency fb in the ultrasonic vibration device 100 will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a graph showing the change over time of the current J1 flowing through the ultrasonic transducer 11A. In Fig. 6, the vertical axis shows the current J1 flowing through the ultrasonic transducer 11A, and the horizontal axis shows the elapsed time from when the current J1 starts to flow. Fig. 7 is an enlarged view of the frequency characteristic of the impedance Z shown in Fig. 4, in the vicinity of the anti-resonance frequency fb.

[0034] As shown in Fig. 6, the current J1 decreases as time passes. In other words, this means that in the ultrasonic vibration device 100, the impedance Z for the same frequency increases as time passes. This is thought to be because, as shown in Fig. 7, the temperature of the ultrasonic horn 11 including the ultrasonic vibrator 11A and the horn body 11B increases as time passes due to ultrasonic vibration, changing the capacitance component of the ultrasonic horn 11 and shifting the anti-resonance frequency fb to a frequency fb2 on the lower wave number side.

[0035] In other words, even if the frequency fc of the oscillation signal S1 is lower than the anti-resonant frequency fb when the current J1 starts to flow, over time it may become equal to or higher than the anti-resonant frequency fb2 that has shifted with the rise in temperature. In this case, the ultrasonic vibrator 11A does not normally vibrate ultrasonically.

[0036] To avoid this, as shown in step S14 of Fig. 5, in the ultrasonic vibration device 100, the frequency of the oscillation signal S1 is set to fc [Hz], which is lower by fs [Hz] than the frequency at which the current J1 becomes smaller than the threshold min. As an example, fs [Hz] is 200 [Hz]. This is because it has been found through experiments that the anti-resonance frequency fb is lower by about 10 [Hz] for a temperature rise of 1°C, and that the temperature rise when the ultrasonic horn 11 is continuously driven is suppressed to less than 20°C. Note that fc [Hz] is a frequency closer to the anti-resonance frequency fb than the resonance frequency fa.

[0037] In this way, by setting the oscillation frequency fc in the ultrasonic vibration device 100 to a frequency greater than the resonant frequency fa and less than the anti-resonant frequency fb, and closer to the anti-resonant frequency fb than the intermediate frequency between the resonant frequency fa and the anti-resonant frequency fb, the current flowing through the ultrasonic vibration device 100 is smaller than when the oscillation frequency is set closer to the resonant frequency fa, and therefore it is possible to keep the power consumption in the ultrasonic vibration device 100 low.

[0038] Next, with reference to FIG. 4, a change in the frequency characteristic of the impedance Z in the ultrasonic vibration device 100 according to the usage state of the ultrasonic cleaner 1 will be described.

[0039] In this embodiment, it has been found that the frequency characteristics (impedance characteristics) of the impedance Z in the ultrasonic vibration device 100 differ when the ultrasonic horn 11 is in contact with air, water, etc. (unloaded state) from when the ultrasonic horn 11 is in contact with the object to be cleaned (loaded state).

[0040] In FIG. 4, the frequency characteristic Za of the impedance Z in the unloaded state is shown by a solid line, and the frequency characteristic Zb of the impedance Z in the loaded state is shown by a dashed line. In the frequency characteristic Zb, the impedance Z is larger in a predetermined frequency band centered on the resonant frequency fa, and the impedance Z is smaller in a predetermined frequency band centered on the anti-resonant frequency fb, compared to the frequency characteristic Za. Specifically, the impedance at the frequency fc set as the oscillation frequency of the oscillation signal S1 decreases from the impedance Z1 in the frequency characteristic Za to the impedance Z2 in the frequency characteristic Zb. That is, at the frequency fc, the current flowing through the ultrasonic horn 11 in the loaded state is larger than that in the unloaded state, so that the ultrasonic horn 11 is driven to a higher output in the loaded state than in the unloaded state. Therefore, the ultrasonic cleaner 1 can be driven with low power consumption in the unloaded state, and can be driven to a higher output in the loaded state than in the unloaded state.

[0041] The frequency fc set as the oscillation frequency of the oscillation signal S1 is set lower than the anti-resonance frequency fb by at least fs, so that even if the impedance Z in the ultrasonic vibration device 100 fluctuates within the range in which the temperature rise of the ultrasonic horn 11 is expected, the ultrasonic vibration can be normally performed. As shown in Fig. 6, the current J1 decreases as the temperature of the ultrasonic horn 11 rises, so that the temperature of the ultrasonic horn 11 reaches a plateau due to the decrease in the amount of heat generated and the increase in the difference with the ambient temperature. Therefore, by appropriately setting the threshold min of the current J1, the temperature rise range of the ultrasonic horn 11 can be controlled.

[0042] Next, adjustment of the oscillation frequency based on the usage environment of the ultrasonic cleaner 1 will be described with reference to FIGS.

[0043] As described above, the frequency characteristic of the impedance Z changes based on the ambient temperature. That is, the anti-resonant frequency fb changes based on the air temperature when the ultrasonic cleaner 1 is used. As a result, the anti-resonant frequency fb may be shifted to a lower frequency side than the oscillation frequency of the oscillation signal S1.

[0044] To avoid this, in this embodiment, the ultrasonic cleaner 1 measures the ambient air temperature or the temperature of the horn body 11B, and adjusts the oscillation frequency of the oscillation signal S1 according to the measurement result. As an example, the ultrasonic cleaner 1 measures the ambient air temperature or the temperature of the horn body 11B when the ultrasonic cleaner 1 is powered on.

[0045] Specifically, when the drive unit 12 is switched from a stopped state to a driven state by pressing the push button switch 10C shown in Fig. 2, the temperature sensor 13 shown in Fig. 2 measures the ambient air temperature or the temperature of the horn body 11B. The type and measurement method of the temperature sensor 13 are not particularly limited as long as the measurement result can be output as an electrical signal. The temperature sensor 13 is disposed, for example, in a portion of the body cover 10A that covers the horn body 11B, or on the circuit board of the drive unit 12.

[0046] Temperature sensor 13 outputs temperature information, which is an electrical signal indicating the measured temperature, to the processor of drive unit 12. When the processor of drive unit 12 receives the temperature information, signal output unit 121 adjusts the frequency of oscillation signal S1 based on the temperature information. This maintains the oscillation frequency in the range from resonance frequency fa to anti-resonance frequency fb, regardless of the ambient air temperature or the temperature of horn body 11B. Therefore, ultrasonic vibration is possible in ultrasonic cleaner 1, regardless of the ambient air temperature or the temperature of horn body 11B.

[0047] As an example, when the ultrasonic cleaner 1 is manufactured, the manufacturing environment is adjusted to 25° C. In other words, the frequency fc, which is the oscillation frequency of the oscillation signal S1 set when the ultrasonic cleaner 1 is manufactured, is set based on the anti-resonance frequency fb at 25° C. Therefore, when the temperature indicated by the measurement result by the temperature sensor 13 is different from 25° C., the signal output unit 121 changes the frequency fc of the oscillation signal S1.

[0048] Specifically, the signal output unit 121 sets the oscillation frequency of the oscillation signal S1 lower as the temperature indicated by the measurement result increases. This allows the oscillation frequency to be maintained lower than the anti-resonance frequency even when the ambient air temperature or the temperature of the horn body 11B is high. For example, when the temperature indicated by the measurement result is 30°C, the anti-resonance frequency fb shown in FIG. 7 is considered to be a frequency fb2 that is shifted to the lower frequency side. For the sake of simplicity, the anti-resonance frequency when the temperature is 30°C is the frequency fb2 based on the temperature rise caused by oscillation, but there is no correlation between 30°C and the temperature rise caused by oscillation.

[0049] For example, the signal output unit 121 calculates the temperature difference between the temperature indicated by the measurement result and 25°C, and determines the amount of shift in the frequency of the oscillation signal S1 according to the calculated temperature difference. Specifically, the signal output unit 121 calculates the amount of shift in frequency corresponding to a temperature difference of "5°C". As described above, since the anti-resonant frequency changes by about 10 [Hz] for a change of 1°C, the signal output unit 121 calculates the amount of shift in frequency to be 50 [Hz]. The signal output unit 121 sets the frequency fc2, which is 50 [Hz] lower than the frequency fc, as the oscillation frequency.

[0050] On the other hand, if the temperature indicated by the measurement result is lower than 25°C, the signal output unit 121 calculates the amount of frequency shift corresponding to the temperature difference, and sets the oscillation frequency to frequency fc3, which is obtained by shifting the frequency fc to the higher frequency side by the calculated amount of shift.

[0051] Note that, other than calculating the amount of frequency shift based on the temperature difference, the signal output section 121 may select, for example, one of a plurality of stages of oscillation frequencies according to the temperature difference.

[0052] As an example, the signal output unit 121 sets the oscillation frequency to frequency fc2 when the temperature difference is between "0° C." and "+5° C.", and sets the oscillation frequency to frequency fc4 (not shown) lower than frequency fc2 when the temperature difference is greater than "+5° C." In this case, for example, information indicating the relationship between the temperature difference and the oscillation frequency is stored in a storage device.

[0053] In the ultrasonic cleaner 1, the temperature sensor 13 may measure the ambient air temperature or the temperature of the horn body 11B periodically during operation, not only when the power is turned on. In this case, the signal output unit 121 adjusts the frequency of the oscillation signal S1 every time it receives temperature information from the temperature sensor 13.

[0054] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments, and can be implemented in various aspects without departing from the gist of the present invention. In addition, the components disclosed in the above embodiments can be modified as appropriate. For example, a certain component among all the components shown in one embodiment may be added to a component of another embodiment, or some components among all the components shown in one embodiment may be deleted from the embodiment.

[0055] In addition, the drawings are mainly schematic illustrations of each component to facilitate understanding of the invention, and the thickness, length, number, spacing, etc. of each component shown in the drawings may differ from the actual ones due to the convenience of creating the drawings. In addition, the configurations of each component shown in the above embodiment are merely examples and are not particularly limited, and it goes without saying that various modifications are possible within a range that does not substantially deviate from the effects of the present invention. [Industrial Applicability]

[0056] The present invention can be used in the field of ultrasonic vibration. [Explanation of symbols]

[0057] 1: Ultrasonic cleaner 11A: Ultrasonic transducer 11B: Horn body 12: Drive unit 13: Temperature sensor 100: Ultrasonic vibration device C0: Capacitor component C1: Capacitor component L1: Inductance component S1: Oscillation signal S2: Oscillation signal Z: Impedance Z1: Impedance Z2: Impedance fa: resonant frequency fb: Anti-resonance frequency

Claims

1. an ultrasonic transducer that, upon receiving an oscillation signal having a predetermined oscillation frequency, ultrasonically vibrates at the oscillation frequency; a drive unit that outputs the oscillation signal and drives the ultrasonic transducer; Equipped with The driving unit and the ultrasonic transducer are A capacitance component and an inductance component, an impedance characteristic having a resonant frequency and an anti-resonant frequency based on a relationship between the capacitance component and the inductance component; Including, An ultrasonic vibration device, wherein the oscillation frequency is set between the resonant frequency and the anti-resonant frequency and on the anti-resonant frequency side of an intermediate frequency between the resonant frequency and the anti-resonant frequency.

2. The impedance characteristic has a characteristic that the resonant frequency and the anti-resonant frequency decrease with an increase in temperature, The ultrasonic vibration device according to claim 1 , wherein the oscillation frequency is set to a value lower than the anti-resonance frequency by a predetermined frequency or more.

3. The ultrasonic vibration device according to claim 1 or 2, A transmission unit that transmits the ultrasonic vibration of the ultrasonic transducer to an outside. An ultrasonic cleaning device comprising:

4. Further comprising a temperature measuring unit for measuring the temperature of the outside, The ultrasonic cleaning device according to claim 3 , wherein the driving unit adjusts the oscillation frequency based on the external temperature measured by the temperature measuring unit.

5. The ultrasonic cleaning device according to claim 3 , wherein the driving unit sets the oscillation frequency to a lower value as the temperature increases.

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