JP7514243B2 - Ultrasonic cleaner - Google Patents

Description

The present invention relates to a handheld ultrasonic cleaner. This application claims priority to Japanese Patent Application No. 2019-152268, filed on August 22, 2019, the contents of which are incorporated herein by reference.

In recent years, handheld ultrasonic cleaners that can be used for spot washing of clothing and remove dirt by ultrasonic vibration have been commercialized. Such ultrasonic cleaners are configured with a vibration part (e.g., an ultrasonic horn) attached to an ultrasonic vibration element using a piezoelectric material, and the ultrasonic vibration element is driven to apply vibrations at ultrasonic frequencies to the vibration part (e.g., Patent Document 1).

JP 2002-11424 A

Handheld ultrasonic cleaners are usually powered by batteries (including rechargeable batteries). For this reason, in order to extend the continuous use time, it is required to operate with low power consumption. Possible means for reducing power consumption include reducing the driving voltage and driving time. For example, when driving an ultrasonic vibration element with a pulse waveform, the duty ratio of the driving pulse in the driving pulse waveform is reduced to reduce the pulse width. In other words, when the driving pulse waveform when driving at full power is the waveform shown in Figure 9 (a) (e.g., duty ratio 100%), the driving pulse waveform during power saving operation is the waveform shown in Figure 9 (b) (e.g., duty ratio 50%).

However, simply reducing the driving voltage or driving time also reduces the driving power, resulting in a problem of reduced cleaning power.

One aspect of the present invention has been made in consideration of the above problems, and aims to provide an ultrasonic cleaner that can achieve both low power consumption operation and prevention of a decrease in cleaning power.

In order to solve the above problems, an ultrasonic cleaner according to one embodiment of the present invention comprises a vibration generating unit which generates ultrasonic vibrations by application of a drive pulse waveform, a vibration transmission unit which is capable of contacting the object to be cleaned and which transmits the vibrations generated by the vibration generating unit to the object to be cleaned, and a drive pulse generating unit which generates the drive pulse waveform of a predetermined period to be applied to the vibration generating unit, and is characterized in that the drive pulse waveform alternates between ON times during which a drive pulse is applied to the vibration generating unit and OFF times during which no drive pulse is applied.

According to the above configuration, maximum cleaning power can be achieved by applying a drive pulse equivalent to full power drive during the ON time, and cleaning power almost the same as during the ON time can be achieved by maintaining the vibration of the vibration transmission part by inertia during the OFF time. Therefore, by providing an OFF time in the drive pulse waveform, it is possible to reduce the amount of power consumption according to the OFF time while also suppressing a decrease in cleaning power.

In addition, in the above ultrasonic cleaner, the length of the OFF time can be configured to be an integer multiple of the specified period of the drive pulse during the ON time.

According to the above configuration, a drive pulse of the same phase can be applied during all of the repeatedly occurring ON times, thereby preventing unnecessary power consumption due to phase shifts.

In addition, in the above ultrasonic cleaner, the switching from the ON time to the OFF time, and the switching from the OFF time to the ON time can be configured to occur at the timing when the voltage polarity of the driving pulse waveform is reversed.

According to the above configuration, when the vibration transmission unit is at the maximum amplitude position (the position farthest from the vibration center), switching from ON time to OFF time and from OFF time to ON time can be performed, and the amplitude of the vibration transmission unit can be prevented from becoming smaller when switching.

The ultrasonic cleaner can also be configured so that the polarity of the drive pulse immediately before switching from the ON time to the OFF time and the polarity of the drive pulse immediately after switching from the OFF time to the ON time are opposite to each other.

The above configuration makes it possible to prevent power loss when switching from OFF time to ON time.

The ultrasonic cleaner may further include a load detection unit that detects the presence or absence of a load on the vibration transmission unit, and the drive pulse generation unit may be configured to make the OFF time in the drive pulse waveform when there is no load longer than the OFF time in the drive pulse waveform when there is a load.

According to the above configuration, when there is no load on the vibration transmission section, i.e., when the ultrasonic cleaner is not performing cleaning, the OFF time can be extended to further reduce power consumption.

One embodiment of the ultrasonic cleaner of the present invention provides an OFF time in the driving pulse waveform, and maintains the vibration of the vibration transmission part inertially during the OFF time, thereby achieving the effect of achieving both low power consumption driving and prevention of a decrease in cleaning power.

1A to 1D are diagrams showing the appearance of an ultrasonic cleaner according to a first embodiment, where FIG. 1A is a front view, FIG. 1B is a side view, FIG. 1A is a cross-sectional view taken along line AA in FIG. FIG. 2 is a block diagram showing a circuit configuration of the ultrasonic cleaner. 4 is a waveform diagram showing a driving pulse waveform of an ultrasonic cleaner in a power-on state. FIG. 1 is a graph showing the cleaning power-power consumption characteristics of an ultrasonic cleaner. 10A is a waveform diagram showing a driving pulse waveform on which phase control has been performed in accordance with the second embodiment, and FIG. 10B is a waveform diagram showing a driving pulse waveform on which phase control has not been performed. FIG. 2A is a waveform diagram showing one period of a driving pulse waveform, and FIG. 2B is a diagram showing a schematic diagram of the position of a vibrating ultrasonic horn. 1A and 1B are diagrams showing the vibration of the vibration generating part and the horn part of an ultrasonic horn, in which (a) shows the vibration during ON time, (b) shows the vibration during OFF time, and (c) shows the vibration immediately after switching from OFF time to ON time. 1A and 1B are waveform diagrams showing driving pulse waveforms of a conventional ultrasonic cleaner, in which (a) shows the driving pulse waveform when driven at full power, and (b) shows the driving pulse waveform when driven in power-saving mode.

[First embodiment]
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. First, a basic structure of an ultrasonic cleaner 10 (hereinafter simply referred to as cleaner 10) according to the first embodiment will be described with reference to Figs. 1 and 2. Fig. 1 shows the appearance of the cleaner 10, with (a) being a front view, (b) being a side view, (c) being a top view, and (d) being a bottom view. Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1(a). Here, for convenience of explanation, the longitudinal direction of the cleaner 10 is taken as the up-down direction, and the side on which the tip portion 12 is provided is taken as the upper side.

As shown in Figure 1, the appearance of the cleaner 10 is composed of a grip portion 11 and a tip portion 12. The grip portion 11 is the portion that is held by the user, and has a cross section perpendicular to the longitudinal direction that is substantially rectangular. The grip portion 11 is made of a metal such as aluminum.

The tip 12 is tapered from the connection side with the grip 11 toward the tip, and a long and narrow rectangular opening 121 is provided at the tip (upper end) (see FIG. 1(c)). A flat horn 22 is arranged to protrude from the opening 121 to the outside. The tip 12 can be protected by covering it with a cap (not shown) when the cleaner 10 is not in use.

A push button switch 13 and a power cover 14 are provided on the bottom of the cleaner 10 (see FIG. 1(d)). The push button switch 13 switches the power of the cleaner 10 ON/OFF each time the user presses it. The power cover 14 is provided to cover the power jack (not shown) located inside. The cleaner 10 is designed to charge the battery 30 (see FIG. 2) by removing the power cover 14 and inserting a power plug into the power jack. In addition to contact charging using a power source, the cleaner 10 may also be capable of contactless charging by placing the cleaner 10 on an attached charging stand.

2, the cleaning device 10 contains an ultrasonic horn 20, a battery 30, a main circuit board 40, an operation circuit board 41, a step-up transformer 50, etc. The ultrasonic horn 20, the battery 30, the operation circuit board 41, and the step-up transformer 50 are each connected to the main circuit board 40, which is controlled by a control microcomputer 63 (see FIG. 3).

The ultrasonic horn 20 is disposed on the tip side of the cleaner 10, i.e., inside the tip portion 12, and has a vibration generating unit 21 and a horn portion 22 which is a vibration transmitting unit. The vibration generating unit 21 has a piezoelectric body, and ultrasonic vibrations of a predetermined frequency and amplitude are generated when a predetermined drive signal is applied to this piezoelectric body. In the cleaner 10 according to the first embodiment, the vibration generating unit 21 is driven to generate vibrations of 30 to 40 kHz which are suitable for washing clothes.

The horn part 22 is made of metal, and as described above, its tip protrudes outward from the opening 121 of the tip part 12. That is, when the cleaner 10 is in use, the horn part 22 transmits the vibrations generated by the vibration generating part 21 to the object to be cleaned (such as clothes) by contacting its tip with the object to be cleaned. The horn part 22 also has a resonant frequency, which is the same as or close to the predetermined frequency generated by the vibration generating part 21. As a result, the vibrations generated by the vibration generating part 21 are amplified by the horn part 22.

The operation circuit board 41 detects operation of the push button switch 13 and transmits this to the main circuit board 40.

Next, the circuit configuration for driving the cleaner 10 will be described with reference to Figure 3. Figure 3 is a block diagram showing the circuit configuration of the cleaner 10.

The battery 30 is connected to the charging terminal 60 via a boost circuit 61 and a charging control circuit 62. The charging terminal 60 corresponds to the power jack described above, and a voltage of 5 V is applied to it via an adapter, for example. The boost circuit 61 boosts the voltage applied to the charging terminal 60. The charging control circuit 62 controls the battery 30 so that it is appropriately charged by the boosted power source.

The control microcomputer 63 is a main control unit that controls the overall operation of the cleaner 10. The control microcomputer 63 is connected to a display unit 64, a push button switch 13, a drive circuit (drive pulse generating unit) 65, a voltage detection unit 66, and a current detection unit 67. The control microcomputer 63, the drive circuit 65, the voltage detection unit 66, and the current detection unit 67 are mounted on the main circuit board 40.

The display unit 64, which will be described in detail later, is a means for notifying the user of the operating state of the cleaner 10 by displaying it. The push button switch 13 is operated by the user to drive the control microcomputer 63. The drive circuit 65 generates a drive signal for the ultrasonic horn 20, i.e., a drive pulse waveform, based on the drive frequency of the drive signal input from the control microcomputer 63. The step-up transformer 50 is connected to the battery 30, the drive circuit 65, and the ultrasonic horn 20, and boosts the voltage from the battery 30 based on the drive pulse waveform input from the drive circuit 65, and applies an AC voltage to the ultrasonic horn 20 (more specifically, the vibration generating unit 21). Here, the AC voltage waveform applied to the ultrasonic horn 20 reflects the drive pulse waveform, so it can be considered as a boosted drive pulse waveform.

The voltage detection unit 66 detects the voltage of the battery 30 and inputs the detected voltage to the control microcomputer 63. When the voltage detected by the voltage detection unit 66 falls below a certain voltage, the control microcomputer 63 detects a low battery and turns off the power to the cleaner 10. The current detection unit 67 detects the drive current of the ultrasonic horn 20 (for example, the drive current generated in the drive circuit 65) and inputs the detected current to the control microcomputer 63.

When using the cleaner 10, the push button switch 13 is operated to turn the cleaner 10 on, and the tip of the vibrating horn 22 is pressed against the part of the object to be cleaned. At this time, the part of the object to be cleaned contains a cleaning medium (water, or water containing detergent). The vibration of the horn 22 is transmitted to the object to be cleaned via the cleaning medium, causing dirt adhering to the object to float and flow into the cleaning medium. This removes the dirt adhering to the object to be cleaned.

The cleaner 10 according to the first embodiment is characterized by a driving method that can achieve both low power consumption and suppression of deterioration of cleaning power. This characteristic is described in detail below.

Figure 4 is a waveform diagram showing the driving pulse waveform of the cleaner 10 when the power is ON. As shown in Figure 4, the driving pulse waveform of the cleaner 10 alternates between ON time and OFF time.

During the ON time of the driving pulse waveform, the duty ratio of each driving pulse is not changed, and the same driving pulse (for example, a driving pulse with a duty ratio of 100%) as that during full power driving shown in FIG. 9(a) is applied. That is, the cleaner 10 can exert maximum cleaning power during the ON time. On the other hand, during the OFF time of the driving pulse waveform, no driving pulse is applied (duty ratio 0%). However, during this OFF time, the vibration of the ultrasonic horn 20 during the ON time is maintained by inertia due to the resonance of the horn part 22, and although there is some attenuation, the ultrasonic horn 20 vibrates at approximately the same frequency and amplitude as during the ON time. That is, the cleaner 10 during the OFF time can exert approximately the same cleaning power as during the ON time.

In this way, the cleaner 10 according to the first embodiment can reduce power consumption according to the OFF time by providing an OFF time in the driving pulse waveform when the power is ON. Also, by operating the ultrasonic horn 20 inertially even during the OFF time, it is possible to suppress a decrease in cleaning power while maintaining low power consumption. In addition, in an experiment conducted by the inventor of the present application, it was confirmed that up to an ON duty (the ratio of ON time to the total driving time (ON time + OFF time)) of 80%, a cleaning power equivalent to that during full power driving with an ON duty of 100% can be maintained.

In addition, the cleaner 10 according to the first embodiment can further reduce power consumption by further reducing the ON duty, if a certain degree of reduction in cleaning power is allowed. Here, the evaluation results of cleaning power when the ON duty is changed to reduce power consumption in the cleaner 10 are shown in FIG. 5 below. In FIG. 5, when changing the ON duty, the ON time is fixed at 2.7 ms while the OFF time is changed. The frequency of the driving pulse waveform is set to approximately 38 kHz.

As shown in Figure 5, the cleaning power of the cleaner 10 decreases as power consumption decreases (the amount of power consumption reduction increases). As shown by the results in Figure 5, power consumption can be reduced according to the tolerable limit of the reduction in cleaning power in the cleaner 10. For example, if the cleaning power of the cleaner 10 can be tolerated up to 80%, power consumption can be reduced to 30% (power consumption reduction of 70%) by reducing the ON duty.

Furthermore, the cleaner 10 according to the first embodiment may have a plurality of power levels with different cleaning powers. For example, based on the results shown in FIG. 5, the power level may be set to "large" when the cleaning power is 100% (ON duty with power consumption of about 80%), "medium" when the cleaning power is 90% (ON duty with power consumption of about 60%), and "small" when the cleaning power is 80% (ON duty with power consumption of about 30%), so that the user can select any power level. This allows the user to lower the power level of the cleaner 10 when using the cleaner 10 depending on the degree of dirt on the object to be cleaned and the fabric quality of the object to be cleaned. In addition, it is preferable that the power level selected by the user is notified by a display (e.g., an indicator display) on the display unit 64. In addition, the cleaner 10 may have a full power level with no OFF time in the driving pulse waveform (ON duty is 100%) as one of the power levels that the user can select.

In addition, in the above-mentioned driving method, the switching cycle of the ON time and the OFF time must also be set appropriately. That is, if the switching cycle is long, the ON time and the OFF time will be long accordingly, and the vibration damping of the ultrasonic horn 20 during the OFF time will be large, leading to a decrease in cleaning power. For this reason, it is necessary to adjust the ON time to an appropriate length so that the vibration damping of the ultrasonic horn 20 does not become too large (the OFF time is determined based on the ON time). However, the appropriate ON time depends on the damping vibration characteristics of the ultrasonic horn 20, and the allowable range of the appropriate ON time is appropriately set according to the design dimensions of the cleaner 10, etc. For example, when the ultrasonic horn 20 is large and the damping vibration time is long, the inertial force on the ultrasonic horn 20 is large, so the ON time is made longer (the switching cycle is made longer) compared to when the ultrasonic horn 20 is small.

In addition, it is preferable that the ON time is at least the time that includes multiple consecutive driving pulse waveforms, for example, a time that includes 10 pulses or more. This allows the ultrasonic horn 20 to efficiently provide the vibrations necessary to resonate. It is also preferable that the ON time is such that the period consisting of the sum of the ON time and the OFF time is not too long. For example, the period consisting of the sum of the ON time and the OFF time is not more than 20 ms, more preferably not more than 10 ms. This prevents the cleaner 10 from generating low-frequency vibrations that cause discomfort to the user.

[Embodiment 2]
In the above embodiment 1, the basic driving method of the cleaner 10 was described, but if the intermittent driving inhibits the vibration due to the inertia of the ultrasonic horn 20, the ultrasonic horn 20 cannot be vibrated efficiently, resulting in wasteful power consumption. In order to prevent this wasteful power consumption, it is preferable to perform phase control of the driving pulse waveform. In this embodiment 2, the phase control of the driving pulse waveform will be described.

As described in the first embodiment, in the driving method of the cleaner 10, ON and OFF times are alternately generated in the driving pulse waveform. In this case, if the phase of the driving pulse applied when the OFF time changes to the ON time is out of phase with respect to the phase of the driving pulse applied during the previous ON time, it inhibits the vibration due to the inertia of the ultrasonic horn 20, leading to unnecessary power consumption.

In order to prevent such inhibition of the inertial vibration of the ultrasonic horn 20, in this embodiment, as shown in Fig. 6(a), the phase of the drive pulse applied during the ON time is controlled so that it is the same phase during all the repeatedly occurring ON times. In other words, the length of the OFF time is set to an integer multiple of one period of the drive pulse during the ON time.

The driving pulse waveform shown in FIG. 6(b) is a comparative example, and shows a case where no phase control is performed and the phase of the driving pulse is shifted between the first ON time and the second ON time. In the driving pulse waveform shown in FIG. 6(b), the vibration of the ultrasonic horn 20 generated during the first ON time continues inertially even during the subsequent OFF time. That is, the vibration of the ultrasonic horn 20 generated during the OFF time can be considered to be a vibration generated by a virtual pulse having the same phase as the driving pulse waveform of the previous ON time. If the phase of the driving pulse waveform applied when switching from this OFF time to the second ON time is shifted from the virtual pulse, an action that inhibits the vibration generated during the OFF time occurs. That is, at the timing of switching from the OFF time to the ON time, the vibration frequency of the ultrasonic horn 20 changes or the amplitude is reduced (i.e., the inertial vibration is inhibited). Since the driving pulse waveform consumes power to return from this state to the original vibration, unnecessary power consumption occurs.

On the other hand, in the drive pulse waveform shown in FIG. 6(a), the vibration of the ultrasonic horn 20 that occurs during the first ON time continues inertially during the subsequent OFF time. The phase of the drive pulse applied during the second ON time is the same as the phase of the drive pulse applied during the first ON time, and is the same as the phase of the virtual pulse during the OFF time. Therefore, when switching from the OFF time to the ON time, the vibration that occurred during the OFF time is not inhibited. As a result, the vibration of the ultrasonic horn 20 can be smoothly maintained without generating unnecessary power consumption.

Furthermore, in the cleaner 10 according to the second embodiment, it is more preferable to perform the following phase control. Note that the driving pulse waveform shown in FIG. 6A is adapted to perform these phase controls as well.
(1) The switching from ON time to OFF time, and from OFF time to ON time, occurs at the timing when the voltage polarity is reversed (the timing of the zero crossing).
(2) The polarity of the drive pulse immediately before switching from an ON time to an OFF time and the polarity of the drive pulse immediately after switching from an OFF time to an ON time are opposite to each other.

By controlling (1) above, when the ultrasonic horn 20 is at the maximum amplitude position (the position farthest from the vibration center), it is possible to switch from ON time to OFF time and from OFF time to ON time. This will be specifically explained with reference to Figure 7.

The ultrasonic horn 20 vibrates for one round trip when a driving pulse for one period shown in FIG. 7(a) is applied. FIG. 7(b) is a diagram showing the position of the vibrating ultrasonic horn 20, where 20A shows the ultrasonic horn 20 at the vibration center (reference position), and 20B and 20C show the ultrasonic horn 20 at the maximum amplitude position. When a pulse of positive polarity is applied to the ultrasonic horn 20 (section P1 to P3 in FIG. 7(a)), the ultrasonic horn 20 moves to the right in FIG. 7(b) (movement from 20B to 20C). And when a pulse of negative polarity is applied to the ultrasonic horn 20 (section P3 to P5 in FIG. 7(a)), the ultrasonic horn 20 moves to the left in FIG. 7(b) (movement from 20C to 20B). Note that FIG. 7 is a schematic diagram, and the direction of movement of the ultrasonic horn 20 is not limited to this figure.

7(a) at the timings of P1 and P5, at the timing of 20C, and at the timings of P2 and P4 at the position of 20A. As a result, when switching from ON time to OFF time and switching from OFF time to ON time are performed at the timing of the zero crossing of the drive pulse waveform (timing of P1, P3 or P5), the switching will be performed when the ultrasonic horn 20 is at the maximum amplitude position.

In contrast, if the drive pulse waveform is switched at a timing other than the zero crossing, for example, at timing P2 or P4, the switch occurs when the ultrasonic horn 20 is not at the maximum amplitude position. As a result, the drive pulse waveform does not drive the ultrasonic horn 20 sufficiently, and the amplitude of the ultrasonic horn 20 becomes small.

In addition, the control in (2) above can prevent power loss when switching from OFF time to ON time. This will be explained in detail with reference to Figure 8. Note that Figure 8 is also a schematic diagram, and the direction of movement of the ultrasonic horn 20 is not limited to that shown in this diagram.

When a drive pulse is applied to the ultrasonic horn 20 during the ON time, this drive pulse acts on the vibration generating unit 21 of the ultrasonic horn 20, causing vibrations in the vibration generating unit 21. The vibrations generated in the vibration generating unit 21 are then transmitted to the horn unit 22. The state at this time is shown in Figure 8 (a).

When switching from ON time to OFF time, the vibration generating unit 21 stops vibrating and only the horn unit 22 vibrates inertially. The state at this time is shown in Figure 8 (b). At this time, the stopping position of the vibration generating unit 21 depends on the polarity of the drive pulse immediately before switching from ON time to OFF time. In the example of Figure 8 (b), the polarity of the drive pulse immediately before switching is positive polarity, and the vibration generating unit 21 stops at the end (right end) of the movement direction (right direction) when the positive polarity pulse is applied.

Next, when the time switches from OFF to ON, a drive pulse is applied again and the vibration generating unit 21 starts vibrating. However, if the polarity of the drive pulse immediately after switching from OFF to ON is the same positive polarity as the polarity of the drive pulse immediately before switching from ON to OFF, the vibration generating unit 21 stops at the end of the movement direction when the positive polarity pulse is applied, so the vibration generating unit 21 cannot move any further immediately after the application of the drive pulse, resulting in a power loss.

On the other hand, if the polarity of the drive pulse immediately after switching from OFF time to ON time is opposite to the polarity of the drive pulse immediately before switching from ON time to OFF time, the vibration generating unit 21 becomes movable immediately after the application of the drive pulse, so no power loss occurs.

In the phase control described in the second embodiment, the control microcomputer 63 controls the timing of switching between the ON time and the OFF time by time control using a timer (not shown). At this time, the timer is configured to count using an oscillation source (clock) for the drive pulse waveform. This makes it possible to prevent misalignment between the drive pulse waveform and the timer. The control microcomputer 63 may also generate the drive pulse waveform directly.

Third Embodiment
In the third embodiment, a description will be given of more suitable drive control for cleaner 10. Specifically, a description will be given of a method for further reducing power consumption by changing the OFF time depending on the presence or absence of a load (contact with water or an object to be cleaned) when cleaner 10 is driven.

When the cleaner 10 is in use, the tip of the cleaner 10 (i.e., the horn portion 22) is not always in contact with water or the object being cleaned, and the cleaner 10 is not always under load. For this reason, a load detection unit that detects the presence or absence of a load is provided in the cleaner 10, and when there is no load, the OFF time is automatically lengthened compared to when there is a load, thereby further reducing power consumption. In addition, when a no-load state is detected for a predetermined period of time or longer, the cleaner 10 may be stopped (ON duty is 0%) by auto power off.

In the cleaner 10, the method of detecting the presence or absence of a load is not particularly limited, but one example is a method of detecting the presence or absence of a load based on the drive current of the ultrasonic horn 20. In this case, the current detection unit 67 shown in FIG. 3 detects the drive current during the ON time and inputs it to the control microcomputer 63. The drive current when there is a load increases compared to the drive current when there is no load. For this reason, the control microcomputer 63 can compare the drive current input from the current detection unit 67 with a predetermined threshold value, and determine that there is a load when the drive current is equal to or greater than the threshold value, and determine that there is no load when the drive current is less than the threshold value. In this example, the current detection unit 67 and the control microcomputer 63 correspond to the load detection unit described in the claims. In addition, when there is no load in the cleaner 10 and the OFF time is extended or the auto power off is set, it is preferable to notify this by the display (e.g., an indicator display) of the display unit 64.

Another method for detecting the presence or absence of a load on the cleaner 10 is, for example, to determine the load based on the phase difference between the voltage and current on the secondary side of the step-up transformer 50. With this method, when there is a load, the voltage and current are close to the same phase, but when there is no load, the voltage and current are out of phase with each other by 90°. This makes it possible to detect the presence or absence of a load on the cleaner 10.

The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention is not interpreted solely by the above-described embodiments, but is defined by the claims. Also, all modifications within the scope and meaning equivalent to the claims are included.

Claims (4)

a vibration generating unit that generates ultrasonic vibrations by applying a driving pulse waveform;
a vibration transmission unit capable of contacting an object to be cleaned and transmitting vibrations generated by the vibration generation unit to the object to be cleaned;
a drive pulse generating unit that generates the drive pulse waveform having a predetermined period and amplitude to be applied to the vibration generating unit,
In the driving pulse waveform, an ON time during which a driving pulse is applied to the vibration generating unit and an OFF time during which a driving pulse is not applied are alternately generated,
The ON time is a time during which a plurality of the drive pulses are consecutively included, and during the ON time, the duty ratio of the drive pulses is constant;
An ultrasonic cleaner according to claim 1, wherein the length of the OFF time is an integer multiple of the predetermined period of the drive pulse during the ON time . 2. The ultrasonic cleaner according to claim 1 ,
The ultrasonic cleaner according to claim 1, wherein the switching from the ON time to the OFF time and the switching from the OFF time to the ON time are performed at a timing when the voltage polarity of a driving pulse waveform is switched. 3. The ultrasonic cleaner according to claim 1 ,
An ultrasonic cleaner characterized in that the polarity of the drive pulse immediately before switching from the ON time to the OFF time and the polarity of the drive pulse immediately after switching from the OFF time to the ON time are opposite to each other. a vibration generating unit that generates ultrasonic vibrations by applying a driving pulse waveform;
a vibration transmission unit capable of contacting an object to be cleaned and transmitting vibrations generated by the vibration generation unit to the object to be cleaned;
a drive pulse generating unit that generates the drive pulse waveform having a predetermined period to be applied to the vibration generating unit,
In the driving pulse waveform, an ON time during which a driving pulse is applied to the vibration generating unit and an OFF time during which a driving pulse is not applied are alternately generated,
a load detection unit that detects the presence or absence of a load on the vibration transmission unit,
An ultrasonic cleaner characterized in that the drive pulse generating unit makes the OFF time in the drive pulse waveform when there is no load longer than the OFF time in the drive pulse waveform when there is a load.

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