Ultrasonic vibration device and ultrasonic cleaning device

Abstract

The invention provides an ultrasonic vibration device and an ultrasonic cleaning device. An ultrasonic vibration device is provided with an ultrasonic vibrator and a drive unit. When an oscillation signal having a predetermined oscillation frequency is received, the ultrasonic vibrator operates at the oscillation frequency. The drive unit outputs an oscillation signal to drive the ultrasonic vibrator. The drive unit and the ultrasonic transducer include impedance characteristics having a resonance frequency and an anti-resonance frequency on the basis of the relationship between the capacitance component and the inductance component. The oscillation frequency is set at the resonance frequency and the anti-resonance frequency and is closer to the anti-resonance frequency side than a frequency between the resonance frequency and the anti-resonance frequency.

Description

Technical Field

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

[0002] The ultrasonic treatment device disclosed in Japanese Patent Laid-Open No. 63-212342 comprises: a device body having an ultrasonic vibrator and an ultrasonic transmitter for transmitting ultrasonic waves generated in the ultrasonic vibrator; a detection unit for detecting the impedance or Q value of the device body at the time of resonance; and a control unit for controlling the power supplied to the ultrasonic vibrator using a signal from the detection unit.

[0003] The ultrasonic vibrator used in the ultrasonic treatment device disclosed in Japanese Patent Laid-Open No. 63-212342 is most likely to resonate at the resonance frequency. Therefore, usually, the oscillation frequency of the ultrasonic vibrator is often set based on the resonance frequency. On the other hand, if the oscillation frequency of the ultrasonic vibrator is set based on the resonance frequency, the current flowing through the ultrasonic treatment device becomes larger, and the power consumption in the ultrasonic treatment device becomes larger.

[0004] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an ultrasonic vibration device and an ultrasonic cleaning device capable of suppressing power consumption to a low level. Summary of the invention

[0005] The ultrasonic vibration device involved in the present invention includes an ultrasonic vibrator and a driving unit. When receiving an oscillation signal having a predetermined oscillation frequency, the ultrasonic vibrator operates at the oscillation frequency. The driving unit outputs the oscillation signal to drive the ultrasonic vibrator. The driving unit and the ultrasonic vibrator include: a capacitance component and an inductance component; and an impedance characteristic, which has 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 at the anti-resonant frequency side compared to the middle frequency between the resonant frequency and the anti-resonant frequency.

[0006] According to the present invention, power consumption can be suppressed to be low. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is an external view of the ultrasonic cleaner according to this embodiment. Figure 2 This is a functional block diagram of the ultrasonic cleaner according to this embodiment. Figure 3 It is a diagram showing an equivalent circuit of the ultrasonic vibration device according to the present embodiment. Figure 4 It is a diagram showing the frequency characteristics of impedance in the ultrasonic vibration device according to the present embodiment. Figure 5This is a flowchart showing a method for setting the oscillation frequency in the ultrasonic vibration device. Figure 6 This is a diagram showing the temporal change of the current flowing through the ultrasonic transducer. Figure 7 yes Figure 4 An enlarged view of the impedance frequency characteristics near the antiresonance frequency is shown. DETAILED DESCRIPTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same reference numerals are attached to the same or corresponding parts in the drawings, and their description will not be repeated.

[0009] Reference Figure 1 and Figure 2 , the structure of the ultrasonic cleaner 1 according to the embodiment of the present invention will be described. Figure 1 1 is a diagram showing the appearance of an ultrasonic cleaner 1 according to the present embodiment. Figure 2 This is a functional block diagram of the ultrasonic cleaner 1 according to the present embodiment.

[0010] The ultrasonic cleaner 1 includes a main body cover 10A, a push button switch 10C, an ultrasonic oscillator 11, a driving unit 12, and a temperature sensor 13. The ultrasonic cleaner 1 is an example of an ultrasonic cleaning device.

[0011] The main body cover 10A is a cylindrical member covering the ultrasonic vibrator 11, the driving unit 12 and the temperature sensor 13. A bottom cover 10B is installed on one axial side of the main body cover 10A. In this embodiment, a button switch 10C is provided in the center of the bottom cover 10B. The button switch 10C is, for example, a power switch, and is a switch for switching the driving and stopping of the driving unit 12.

[0012] The ultrasonic vibrator 11 performs ultrasonic vibration. Specifically, the ultrasonic vibrator 11 includes an ultrasonic vibrator 11A and a vibrator body 11B. When the ultrasonic vibrator 11A receives an oscillation signal S1 which is an alternating voltage having a predetermined frequency, it performs ultrasonic vibration at the frequency of the oscillation signal S1. The vibrator body 11B is, for example, a flat metal component. Typically, the vibrator body 11B is made of iron, titanium, or aluminum. The vibrator body 11B is attached to the ultrasonic vibrator 11A. Figure 1 As shown in FIG. 1 , the head main body 11B is disposed in the main body cover 10A so that a part of the head main body 11B is exposed from the main body cover 10A. The head main body 11B vibrates in accordance with the vibration of the ultrasonic vibrator 11A.

[0013] In other words, the ultrasonic vibration of ultrasonic vibrator 11A is transmitted to a medium such as air or water or an object to be cleaned by ultrasonic cleaner 1 via head body 11B. That is, head body 11B transmits the ultrasonic vibration of ultrasonic vibrator 11A to the outside of body cover 10A. Head body 11B is an example of a transmission unit.

[0014] The driving unit 12 outputs an oscillation signal S1 to drive the ultrasonic vibrator 11A. For example, the driving unit 12 includes a driving circuit (not shown), a battery (not shown) for supplying power to the driving circuit, and a signal output unit 121. The driving circuit may also include: circuit elements such as resistors, capacitors, coils, and power supplies; processors such as CPUs (Central Processing Units); storage devices such as memories for storing data and computer programs; and circuit substrates on which circuit elements, processors, and storage devices are mounted.

[0015] As an example, a processor that functions as a signal output unit 121 is installed as a driving circuit of the driving unit 12. Specifically, when the processor of the driving 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 predetermined frequency to the ultrasonic vibrator 11A. Hereinafter, the oscillation signal S1 and the predetermined frequency in the ultrasonic vibrator 11A are referred to as oscillation frequencies. In the present embodiment, the ultrasonic vibrator 11A and the driving unit 12 constitute the ultrasonic vibration device 100.

[0016] It should be noted that 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.

[0017] Next, refer to Figure 3 and Figure 4 , the setting of the oscillation frequency is explained. Figure 3 1 is a diagram showing an equivalent circuit T1 of the ultrasonic vibration device 100 according to the present embodiment. Figure 4 : is a graph showing the frequency characteristic of the impedance Z in the ultrasonic vibration device 100 according to the present embodiment. Hereinafter, the frequency characteristic of the impedance Z may be simply described as the impedance characteristic.

[0018] In this embodiment, the ultrasonic vibrator 11A and the driving unit 12 include capacitance components and inductance components. Figure 3 As shown, the circuit configuration of the ultrasonic vibration device 100 can be expressed by an equivalent circuit including a capacitance component and an inductance component.

[0019] like Figure 3As shown, the equivalent circuit T1 of the ultrasonic vibration device 100 is represented by the parallel connection of the inductance component L1, the capacitance component C1 and the resistance component R1 connected in series and the capacitance component C0. Therefore, in the equivalent circuit T1, the resonance frequency fa and the anti-resonance frequency fb exist based on the relationship between the capacitance component and the inductance component.

[0020] The resonance frequency fa is obtained by the following equation (1) using the inductance component L1, the capacitance components C1 and C0, and the resistance component R1.

[0021] [Mathematical formula 1]

[0022] The anti-resonance frequency fb is obtained by the following equation (2) using the inductance component L1, the capacitance components C1 and C0, and the resistance component R1.

[0023] [Mathematical formula 2]

[0024] like Figure 4 As shown in FIG. 1 , the impedance Z in the equivalent circuit T1 is minimum (extremely small) at the resonant frequency fa, and maximum (extremely large) at the anti-resonant frequency fb. That is, the resonant frequency fa is a frequency at which current can easily flow 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 cannot easily flow through the circuit, and a high voltage is required for driving the circuit, but on the other hand, it is a frequency at which power consumption can be suppressed to a low level. Figure 4 In the example of , the resonant frequency fa is approximately 38 [kHz] and the anti-resonant frequency fb is approximately 39 [kHz].

[0025] Here, the ultrasonic vibrator 11A can perform ultrasonic vibration at a frequency greater than the resonance frequency fa and less than the anti-resonance frequency fb. In other words, the ultrasonic vibrator 11A does not perform ultrasonic vibration normally at a frequency below the resonance frequency fa or at a frequency above the anti-resonance frequency fb. That is, in the ultrasonic vibration device 100, the oscillation frequency is set to be greater than Figure 4 The resonant frequency fa shown is large and smaller than the anti-resonant frequency fb.

[0026] Next, refer to Figure 5 , a method for setting the oscillation frequency in the ultrasonic vibration device 100 is described. Figure 5 : is a flowchart showing a method of setting the oscillation frequency of the ultrasonic vibration device 100 .

[0027] In the present embodiment, the inductance component L1, the capacitance components C1, C0, and the resistance component R1 in the ultrasonic vibration device 100 have individual differences. In other words, the inductance component L1, the capacitance components C1, C0, and the resistance component R1 in the ultrasonic vibration device 100 are different from one unit to another. Therefore, in the ultrasonic vibration device 100, the oscillation frequency is set individually for each unit during manufacturing.

[0028] Specifically, first, a signal generating device 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 outputted from the signal generating device, is inputted 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.

[0029] Next, in a state where the oscillation signal S2 is input to the ultrasonic vibration device 100, the current J1 flowing through the ultrasonic vibrator 11A is measured (step S12).

[0030] Next, the measured current J1 is compared with the threshold value min (step S13). The threshold value min corresponds to the current when an oscillation signal having a frequency before the anti-resonance frequency fb flows through the ultrasonic vibrator 11A. When the current J1 is greater than the threshold value min ("No" in step S13), the frequency of the oscillation signal S2 is increased (step S15). While the oscillation signal S2 after the frequency increase is input to the ultrasonic vibration device 100, the current J1 flowing through the ultrasonic vibrator 11A is measured (step S12).

[0031] On the other hand, when the current J1 is less than the threshold value min (Yes in step S13), the frequency of the oscillation signal S2 is reduced by fs [Hz] and the frequency of the oscillation signal S2 is 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).

[0032] Here, refer to Figure 6 as well as Figure 7 , the relationship between the temperature change of the ultrasonic vibration device 100 and the anti-resonance frequency fb is described. Figure 6 It is a graph showing the temporal change of the current J1 flowing through the ultrasonic transducer 11A. Figure 6 The vertical axis represents the current J1 flowing through the ultrasonic vibrator 11A, and the horizontal axis represents the elapsed time after the current J1 starts to flow. Figure 7 yes Figure 4 An enlarged view of the frequency characteristics of the impedance Z near the anti-resonance frequency fb is shown.

[0033] like Figure 6 As shown in FIG. 1 , the current J1 decreases with the passage of time. In other words, in the ultrasonic vibration device 100, the impedance Z relative to the same frequency increases with the passage of time. This is because, as Figure 7 As shown, the ultrasonic head 11 including the ultrasonic vibrator 11A and the head body 11B increases in temperature over time due to ultrasonic vibration, and the capacitance component of the ultrasonic head 11 changes, so that the antiresonance frequency fb shifts to a frequency fb2 on the lower frequency side.

[0034] That is, even if the frequency fc of the oscillation signal S1 is lower than the antiresonance frequency fb when the current J1 starts to flow, it may become higher than the antiresonance frequency fb2 as time passes, which is shifted with the temperature rise. In this case, the ultrasonic transducer 11A does not normally perform ultrasonic vibrations.

[0035] To avoid this situation, Figure 5 As shown in step S14, in the ultrasonic vibration device 100, the frequency of the oscillation signal S1 is set to fc [Hz] which is lower than the frequency at which the current J1 is lower than the threshold value min by fs [Hz]. As an example, fs [Hz] is 200 [Hz]. This is because it is known through experiments that the anti-resonance frequency fb decreases by about 10 [Hz] with respect to a temperature rise of 1°C, and the temperature rise is suppressed to less than 20°C when the ultrasonic vibration head 11 is continuously driven. In addition, fc [Hz] is a frequency closer to the anti-resonance frequency fb than the resonance frequency fa.

[0036] In this way, by setting the oscillation frequency fc in the ultrasonic vibration device 100 to a frequency that is greater than the resonance frequency fa and less than the anti-resonance frequency fb, and the oscillation frequency fc is closer to the anti-resonance frequency fb side than the intermediate frequency between the resonance frequency fa and the anti-resonance frequency fb, the current flowing through the ultrasonic vibration device 100 becomes smaller than when the oscillation frequency is set to the resonance frequency fa side, so that the power consumption in the ultrasonic vibration device 100 can be suppressed to a lower level.

[0037] Next, refer to Figure 4 , the change in the frequency characteristic of the impedance Z in the ultrasonic vibration device 100 according to the use condition of the ultrasonic cleaner 1 is described.

[0038] In this embodiment, it can be seen that the frequency characteristics (impedance characteristics) of the impedance Z in the ultrasonic vibration device 100 are different when the ultrasonic oscillator 11 is in contact with air, water, etc. (unloaded state) and when the ultrasonic oscillator 11 is in contact with the object to be cleaned (loaded state).

[0039] exist Figure 4In FIG. 1 , the frequency characteristic Za of the impedance Z in the no-load state is represented by a solid line, and the frequency characteristic Zb of the impedance Z in the load state is represented by a dotted line. Compared with the frequency characteristic Za, the frequency characteristic Zb has a larger impedance Z in a frequency band within a specified range centered on the resonant frequency fa, and a smaller impedance Z in a frequency band within a specified range centered on the anti-resonant frequency fb. 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 in the ultrasonic vibrator 11 in the load state is larger than that in the no-load state, so the ultrasonic vibrator 11 is driven with a higher output in the load state than in the no-load state. Therefore, in the ultrasonic cleaner 1, it can be driven with low power consumption in the no-load state, and can be driven with a higher output in the load state than in the no-load state.

[0040] Furthermore, since the frequency fc set as the oscillation frequency of the oscillation signal S1 is lower than the anti-resonance frequency fb by at least an amount fs, even if the impedance Z in the ultrasonic vibration device 100 changes within the range in which the temperature of the ultrasonic vibration head 11 is assumed to rise, ultrasonic vibration can be performed normally. Figure 6 As shown, as the temperature of the ultrasonic oscillator 11 rises, the current J1 decreases, so the temperature of the ultrasonic oscillator 11 reaches a limit due to the decrease in heat generation and the increase in the difference in ambient temperature. Therefore, by appropriately setting the threshold min of the current J1, the temperature rise range of the ultrasonic oscillator 11 can be controlled.

[0041] Next, refer to Figure 2 and Figure 7 , adjustment of the oscillation frequency based on the use environment of the ultrasonic cleaner 1 will be described.

[0042] As described above, the frequency characteristic of the impedance Z changes depending on the ambient temperature. That is, the antiresonance frequency fb changes depending on the air temperature when the ultrasonic cleaner 1 is used. As a result, the antiresonance frequency fb may shift to a lower frequency side than the oscillation frequency of the oscillation signal S1.

[0043] To avoid this, in this embodiment, the ultrasonic cleaner 1 measures the ambient temperature or the temperature of the oscillator 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 temperature or the temperature of the oscillator body 11B when the ultrasonic cleaner 1 is powered on.

[0044] Specifically, when Figure 2 When the push button switch 10C shown is pressed, the driving unit 12 switches from the stopped state to the driven state. Figure 2The temperature sensor 13 shown measures the ambient temperature or the temperature of the vibration head 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, for example, arranged in a portion of the body cover 10A that covers the vibration head body 11B, or in a circuit board of the drive unit 12.

[0045] The temperature sensor 13 outputs an electrical signal indicating the measured temperature, i.e., temperature information, to the processor of the driving unit 12. When the processor of the driving unit 12 receives the temperature information, the signal output unit 121 adjusts the frequency of the oscillation signal S1 based on the temperature information. Thus, regardless of the ambient temperature or the temperature of the vibration head body 11B, the oscillation frequency is maintained within the range from the resonance frequency fa to the anti-resonance frequency fb. Therefore, regardless of the ambient temperature or the temperature of the vibration head body 11B, ultrasonic vibration can be performed in the ultrasonic cleaner 1.

[0046] As an example, when manufacturing the ultrasonic cleaner 1, the manufacturing environment is adjusted to 25° C. That is, the frequency fc, which is the oscillation frequency of the oscillation signal S1 set when manufacturing the ultrasonic cleaner 1, is set based on the anti-resonance frequency fb at 25° C. Therefore, when the temperature indicated by the measurement result of the temperature sensor 13 is different from 25° C., the signal output unit 121 changes the frequency fc of the oscillation signal S1.

[0047] Specifically, the higher the temperature indicated by the measurement result, the lower the oscillation frequency of the oscillation signal S1 is set by the signal output unit 121. Thus, even when the ambient temperature or the temperature of the vibration head body 11B is high, the oscillation frequency can be maintained lower than the anti-resonance frequency. For example, when the temperature indicated by the measurement result is 30°C, Figure 7 The antiresonant frequency fb shown is a frequency fb2 shifted to a lower frequency side. In order to simplify the description, the antiresonant frequency at 30°C is set to the frequency fb2 based on the temperature rise due to oscillation, but there is no correlation between 30°C and the temperature rise due to oscillation.

[0048] For example, the signal output unit 121 calculates the temperature difference between the temperature shown in the measurement result and 25°C, and determines the frequency shift of the oscillation signal S1 based on the calculated temperature difference. Specifically, the signal output unit 121 calculates the frequency shift corresponding to the temperature difference "5°C". As described above, since the anti-resonance frequency changes by about 10 [Hz] with respect to a change of 1°C, the signal output unit 121 calculates the frequency shift as 50 [Hz]. The signal output unit 121 sets the frequency fc2, which is 50 [Hz] lower than the frequency fc, as the oscillation frequency.

[0049] On the other hand, when the temperature indicated by the measurement result is lower than 25° C., the signal output unit 121 calculates the frequency shift amount according to the temperature difference, and sets the frequency fc3 obtained by shifting the calculated shift amount from the frequency fc to the high frequency side as the oscillation frequency.

[0050] In addition, the signal output unit 121 may select one of a plurality of stages of oscillation frequencies according to the temperature difference, for example, in addition to calculating the frequency shift amount according to the temperature difference.

[0051] As an example, the signal output unit 121 is When the temperature difference is greater than +5°C, frequency fc2 is set as the oscillation frequency, and when the temperature difference is greater than +5°C, frequency fc4 (not shown) which is less than frequency fc2 is set as the oscillation frequency. In this case, for example, information indicating the relationship between the temperature difference and the oscillation frequency is stored in the storage device.

[0052] In the ultrasonic cleaner 1 , the temperature sensor 13 may measure the ambient temperature or the temperature of the horn body 11B periodically, not only when the power is turned on, but also when the ultrasonic cleaner 1 is driven. In this case, the signal output unit 121 adjusts the frequency of the oscillation signal S1 each time it receives temperature information from the temperature sensor 13 .

[0053] The embodiments of the present invention are described above with reference to the accompanying drawings. However, the present invention is not limited to the above-mentioned embodiments, and can be implemented in various ways within the scope of the main purpose thereof. In addition, the multiple components disclosed in the above-mentioned embodiments can be appropriately changed. For example, a component of all the components shown in a certain embodiment can be added to the components of another embodiment, or some of the components of all the components shown in a certain embodiment can be deleted from the embodiment.

[0054] In addition, in the drawings, for easy understanding, each component is schematically shown as a main body, and for the convenience of drawing, the thickness, length, number, spacing, etc. of each component shown in the drawings may be different from the actual one. In addition, the configuration of each component shown in the above embodiment is only an example and is not particularly limited. Of course, various changes can be made within the scope that does not substantially deviate from the effect of the present invention.

Claims

1. An ultrasonic vibration device, characterized in that: include: The ultrasonic vibrator, when receiving an oscillation signal having a prescribed oscillation frequency, performs ultrasonic vibration at the oscillation frequency; as well as A driving unit outputs the oscillation signal to drive the ultrasonic vibrator. The driving unit and the ultrasonic vibrator include: capacitive and inductive components; and The impedance characteristic has 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 is set closer to the anti-resonant frequency than a frequency in between the resonant frequency and the anti-resonant frequency.

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

3. An ultrasonic cleaning device, characterized in that: include: The ultrasonic vibration device according to claim 1 or 2; and The transmitting unit transmits the ultrasonic vibration of the ultrasonic vibrator to the outside.

4. The ultrasonic cleaning device according to claim 3, characterized in that: further comprising a temperature measuring unit for measuring the external temperature, The driving unit adjusts the oscillation frequency according to the temperature of the outside measured by the temperature measuring unit.

5. The ultrasonic cleaning device according to claim 3, characterized in that: The drive unit sets the oscillation frequency to a lower value as the temperature increases.

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