JP4850043B2 - Vibration application equipment - Google Patents

Description

The present apparatus relates to a vibration application apparatus, and more particularly to a vibration application apparatus using a piezoelectric body. Specifically, the present invention relates to an ultrasonic cleaning device, a vibration cutting device, a vibration surface treatment device, a material agitation device, and a material condensation device. In particular, the present invention relates to a dental vibration application apparatus and a dental vibration application apparatus using a piezoelectric body. Specifically, the present invention relates to a dental ultrasonic cleaning device, an ultrasonic calculus removing device, a dental vibration cutting device, a dental vibration surface treatment device, a dental material stirring device, and a dental material condensing device. In addition, these dental devices relate to devices that are sold and used around the world with the same specifications.

(Dental material condensing device)
First, a dental material condensing device will be described. This is because when porcelain is built up by building a ceramic crown on a metal crown created according to the shape of the patient's teeth, preparing the shape and firing it, a ceramic powder and liquid such as water are first added. Mix to make porcelain mud, and swell with a brush or spatula on the metal crown to create a porcelain built-up metal crown. Next, excess moisture exudes from the surface of the porcelain that has been raised by applying vibration to the porcelain built-up metal crown, and the porcelain is condensed. Excess water is wiped off or evaporated in some way. By repeating this, the gap between the porcelain powders is narrowed and high-density construction is possible. This action is called condensation, and it is generally said in the dental field that porcelain built up by such a method has little shape shrinkage and shape deformation and increases strength when fired.

Conventionally, two methods have been adopted as methods for applying vibration for condensation during the construction of dental porcelain. One is a manual method to apply a vibration to the dental material holder holding the porcelain built-up metal crown by applying a reciprocating motion to the uneven part on the handle of a legron sword, etc. How to give vibration by giving. The other is to use a machine to attach a metal diaphragm (typical shape of a vibration member) to an electrostrictive or piezoelectric vibrator, and hold the end of the diaphragm and a ceramic-built metal crown. A dental material holding device (a typical vibration load) is brought into contact with each other to apply vibration, and such a device is called a dental material condensing device.
One of the products often used in dental material condensing devices is Ceracon 2 sold by Matsukaze Co., Ltd. FIG. 1 is a schematic diagram showing the operation of the ceramic capacitor 2, FIG. 2 is a block diagram, and FIG. 3 shows drive voltage waveforms and drive current waveforms. In FIG. 1, 1 is a ceramic body 2 body, 2 is a piezoelectric bolted Langevin type vibrator that is a vibrator, 3 is a vibration plate that is a vibration output part, A is a porcelain built-up metal crown, and B is a dental material holding instrument. is there. In FIG. 2, 4 is a commercial power input unit, 5 is a DC power source, 6 is a power converter, 2 is a vibrator, and 7 is a control unit. The power supply path is indicated by a thick line, and the signal supply path is indicated by a thin line. FIG. 3 shows the drive voltage waveform (upper) and drive current waveform (lower) of the bolted Langevin type vibrator 2 at the output of the power converter 6, and the horizontal axis is the time axis. As shown in FIG. 3, the drive voltage is a rectangular wave and the drive current is a sine wave. Dashed lines indicate the upper and lower envelopes of these waveforms.

The frequency of these waveforms is the resonance frequency of the bolt-clamped Langevin type vibrator 2 to which the diaphragm 2 is attached, and is configured to obtain as large a drive vibration speed and drive current as possible with a small voltage. This is realized by a feedback signal from the vibrator 2 to the power converter 6 shown in FIG. In other words, when the power converter 6 is turned on and some voltage is provided to the vibrator 2, the vibrator 2 performs some response, which becomes a feedback signal and is fed back to the power converter. If the open-loop gain at the resonance frequency of the vibrator assuming that feedback is cut off is made larger than 1, the phase is set in the range of -90 degrees (delay) to 90 degrees, and so-called positive feedback is performed, the power converter 6 And the vibrator 2 starts to operate at the resonance frequency of the vibrator 2. FIG. 4 shows the envelope of the waveform of FIG. 3 on a long time axis, and the repetition frequency of the envelope reflects the commercial power supply frequency.

The envelope of the driving voltage in the upper waveform reflects that the DC power supply is half-wave rectifying the commercial power supply input. The drive current is substantially proportional to the drive vibration speed, and even when the envelope of the drive voltage is zero, that is, when the drive voltage becomes zero, the vibration is gradually attenuated.
As for commercial power input, 100V specification products and 240V specification products are separately manufactured and sold in order to cope with different power supply voltages in Japan or outside Japan.
Further, the controller 7 of the ceramic controller 2 can adjust the vibration amplitude by adjusting the magnitude of the driving voltage, and is adjusted from the weakest to the strongest by the amplitude adjustment knob on the panel of the main body 1. However, the maximum strength can be used for various purposes and usage. For example, when a porcelain built-up metal crown A, which is constructed of porcelain without using the aforementioned dental material holding device B as a vibration load, is placed on a dental model and the dental model is condensed as a vibration load. Requires a large amount of vibration, but requires a large vibrator, large power, and a large device. Therefore, in Ceracon 2, while increasing the maximum amplitude as shown in Fig. 4 and suppressing the average power by giving strength to the vibration, the large vibration is periodically generated with a small vibrator, small power, and a small device. It is applied to the load and realizes an efficient condensation effect. For this reason, a so-called half-wave rectified DC power source that only rectifies commercial AC power is used as the DC power source 5.

The vibration of the ceramic controller 2 can be activated / stopped by a switch on the panel between a continuous mode linked with power ON / OFF and a sensor mode activated / stopped by a sensor. Usually, porcelain build-up work is because both hands are often blocked, and it is difficult to start and stop with a switch on the panel. This sensor is an infrared pyroelectric sensor disposed near the diaphragm, and operates to detect the temperature when a hand holding a dental material holder approaches and to stop when the hand is released.

(Ultrasonic calculus removal device)
Next, an ultrasonic calculus removing device will be described. Ultrasonic calculus remover removes tartar plaque, periodontal pocket cleaning, filling of dental filling material, removal of prosthesis, root canal widening, cavity formation, dental cement condensation, implant deposit removal It is widely used to perform such treatments. The ultrasonic calculus removal device uses a vibration member called a tip directly on the teeth, so that a body containing a DC power supply, power converter and control unit, and a handpiece equipped with a vibrator and vibration output unit are included. The structure is connected by a flexible tube that supplies electric power, etc., but the basic configuration is the same as that of a dental material condensing device, except that the shape and characteristics of the vibrator / vibration output unit are different. The vibrator has a long and narrow structure so that it fits in a handpiece having a circular cross section, and the vibration output portion connected to the vibrator is thinly bent at the tip that contacts the teeth, and is called a chip. A tooth surface that becomes a vibration load is applied to this tip. If necessary, a desired treatment is performed by the action of a cleaning liquid ejected from the chip. In this case, the cleaning liquid also becomes a vibration load.
The vibration of the ultrasonic calculus removing device is usually started and stopped by a separate foot pedal. This is also because both hands are often closed when the dentist or dental hygienist who is the operator is facing the patient. Regarding the commercial power input of these ultrasonic calculus removal devices, devices with 100 to 120 V input specifications and devices with 220 to 240 V input specifications are often sold in different specifications. Moreover, in the latest ultrasonic calculus removal apparatus, the example which uses the DC power supply of a fixed voltage output in the commercial power supply input range of 90V-264V, and is used as the power supply of a power converter is seen. As a specific example of such an ultrasonic calculus removing apparatus, there is a piezo master 600 sold by EMS.

(Ultrasonic cleaning device)
The ultrasonic cleaning device is a device in which a cleaning tank containing a liquid such as water is fixedly connected to a vibrator instead of the vibration plate 3 in the material condensing device shown in FIG. 1, and the vibration is propagated in the liquid. . The basic configuration is the same as that of the material condensing device.
The same applies to the vibration cutting device, the vibration surface treatment device, and the material stirring device.
(Other vibration application equipment)
In addition to the above, vibration applied devices include ultrasonic processing machines, ultrasonic welding machines, vibration cutting devices, vibration surface treatment devices, material agitation devices, etc., all of which are fundamental in the sense that they give vibration to the load. The configuration is the same as that of the material condenser. Patent documents 1, 2, and 3 are patent documents that can be applied to an ultrasonic machine. According to these patent documents, a power amplifier is used as a power converter for vibration output, and a fixed output DC power source is used as a power source for the power amplifier.

(General technology and its applicability to vibration application equipment)
The vibration level of these vibration application devices needs to be adjusted in a wide range, and is generally realized by changing the driving voltage of the vibrator. Specifically, the control is performed so that the drive voltage becomes a predetermined value determined by the operation of the operator or the control unit. In a power converter such as a general inverter used for a motor or the like that is not limited to a vibration application device, this drive voltage is inverted between plus and minus without changing the peak voltage within one cycle of the voltage waveform in FIG. A time zone of zero voltage is provided at the timing, and the time zone is adjusted by controlling the average voltage within one period by adjusting the time zone. This is shown in FIG. Note that the ratio of the period of zero voltage within one cycle is called duty. Such a PWM waveform is often expressed as a superposition of a fundamental frequency and a sine wave of a plurality of harmonics, with the repetition frequency of the waveform as the fundamental frequency and a frequency that is an integral multiple of that frequency as a harmonic. A vibration speed is generated in proportion to the fundamental frequency which is the resonance frequency of the vibrator. The amplitude of the sine wave component of the fundamental frequency in this voltage waveform is proportional to the PWM duty. That is, it is conceivable to adjust the vibration level of the vibration application device by controlling the duty.

In addition, if the same device is compatible with a wide range of commercial power inputs from 90V to 264V, it is convenient that only the power cord can be made different specifications and the rest can be made universal specifications, but it is not limited to vibration application devices. In the DC power supply, such a technique has been established, and this is often realized by a PWM type or PFM type switching regulator. In the PWM method, the method used for the power converter in the above description of the general technique is applied to a switching regulator that obtains a constant output voltage even when the commercial input voltage is different. The PFM method adjusts the period of zero voltage by fixing the basic frequency in the PWM method, whereas the PFM method adjusts the period, that is, the basic frequency by fixing the period of zero voltage or voltage peak. . Some also serve as PWM and PFM.
JP-A-5-30107 Ultrasonic generator Method of controlling ultrasonic apparatus JP-A-2005-080463 DC-DC converter and piezoelectric vibrator driving circuit EMS Piezon Master 600 Instruction Manual and Specifications

These vibration application devices are not limited to dental material condensers and ultrasonic calculus removal devices, but are compatible with different commercial power supply voltages in Japan or outside Japan. In many cases, 240V specification products to be operated are manufactured and sold separately. In this case, the difference in commercial power supply voltage has caused problems such as limitation of the country of use and necessity of an external voltage converter. For this reason, it is required to operate from 90V to 264V with the same device.
In addition, if the vibration level of these vibration application devices fluctuates due to the hardness of the load, the mass, the degree of mechanical coupling between the load and the vibration member, the frequency of contact, the fluctuation of the commercial power supply voltage, the temperature characteristics of the vibrator, and the secular change. May be in trouble. For example, in an ultrasonic calculus removal device, a chip that is a vibration member is provided with a through-hole for injecting cleaning liquid, but the cleaning liquid that is part of the vibration load does not reach the chip, and only vibration of the chip without injection Driving has started, and there has been a problem of generating excessive vibration amplitude that greatly exceeds the required amplitude. This excessive amplitude is generated as a result of the influence of the fluctuation of the vibration load even when the tip which is the vibration member contacts the tooth surface which is the vibration load. This excessive amplitude has caused a problem that the chip breaks.

In a dental material condensing device and an ultrasonic cleaning device, a device that maintains a predetermined vibration level determined by an operator and a level set by an operator in a wide commercial power input range of 90 V to 264 V is required.
As a method of keeping these vibration levels at a predetermined level determined by the level set by the operator and the device in a wide commercial power input range of 90V to 264V, the conventional power converter is a PWM method or PFM method. A method for driving control is conceivable. That is, a commercial power supply input voltage or a voltage reflecting the same is detected, or a vibrator current reflecting the vibration speed of the vibrator is detected, and the power converter is set to a PWM method or a PFM method so as to keep these constant values. The drive is controlled by this. In other words, when the commercial power input is large or when the vibration speed of the vibrator is larger than a predetermined value, the duty of the power converter may be reduced, and when it is vice versa, it may be increased. In FIG. 2, the output voltage Vdc of the DC power source 5 is feed-forward input to the control unit 7 or current feedback from the vibrator 2 is input to the control unit 7, and the control unit 7 vibrates when Vdc is large or vibrates. The duty may be reduced when the child current is large, and vice versa. However, there is one major problem with this method. That is, the vibrator 2 performs positive feedback oscillation in which the power converter 6 oscillates in cooperation with the resonance frequency of the vibrator 2 simultaneously with the control by the PWM method or the PFM method. Therefore, in principle, control by the PFM method is impossible. In addition, the oscillation of the vibrator is very sensitive. Abnormal oscillation at a frequency that tends to vibrate, which is called spurious other than the resonance frequency, and abnormal noise caused by excessive vibration level (normal resonance frequency is designed in the ultrasonic region) Therefore, the vibration level is likely to decrease due to the occurrence of abnormal noise) and the phase shift between the drive voltage and the drive current. Further, since it is based only on the PWM method, it is necessary to drive with an extremely short duty, and as a result, it is necessary to take a very large output voltage of the DC power source 5, and the withstand voltage and safe operation area of the elements used in the power converter In addition to the need to increase the electromagnetic field noise, the electromagnetic field noise due to switching of high voltage and large current increases, making it difficult to meet EMC regulations that have recently been tightened worldwide.

In addition, it is necessary to reduce the power consumption by reducing the size of the apparatus as much as possible while realizing the necessary vibration level. For this reason, in the above-mentioned dental material condenser Ceracon 2 for dental use, while increasing the maximum amplitude as shown in FIG. There was one that realized an efficient condensation effect by periodically applying a large vibration to the load with a small power and a small device. However, the ceramic capacitor 2 realized this by adopting a simple circuit for half-wave rectifying the commercial power supply voltage in the DC power supply 5, but the same thing was specified by the operator with the commercial power supply voltage of 90V to 264V. It was difficult to achieve the vibration level.
In addition, there is a problem as to how and when the vibration of the vibration application device is started and stopped. For example, in the case of a dental material condenser, it is usual to repeatedly apply a dental material holding device to the diaphragm to give vibration or to visually check it away from it, and each time the vibration plate of the material condenser is vibrated. While the work of starting and stopping is very complicated, it is a wasteful power consumption to continue the vibration throughout the work. In the above-described Ceracon 2, for this measure, when the dental material holding device is brought close to the vibration plate, the photoelectric sensor provided separately detects that the dental material holding device is approaching, Although it is known that the operation is stopped, the circuit is complicated and large, and a complicated and high-grade photoelectric sensor is used, and there is a problem that it takes time to adjust the sensitivity. Further, in the ultrasonic calculus removing device, a separate foot pedal is required to perform the start / stop control of vibration.

Further, in a general vibration application device, there is a problem that a transient large amplitude generated at the time of start-up or load fluctuation, particularly when contacting a load, deteriorates the vibrator and the bonded portion connecting the vibrator and the vibration member. Further, when feedback control is used for the control unit, there is a risk that this transient amplitude will increase significantly. For example, when a chip that requires a cleaning liquid is used in an ultrasonic calculus removing device, there is a risk that abnormal vibration will start in the absence of the cleaning liquid. Further, in the ultrasonic calculus remover, the stepping pedal is used to control the drive stop of vibration and supply and stop of the cleaning liquid. However, there is a possibility that the supply of the cleaning liquid may be delayed and lead to abnormal vibration. This excessive amplitude has caused a problem that the chip breaks.

In order to solve these problems, in the present invention,
A switching element is provided inside the DC power supply, and one or more voltage detectors / current detectors are provided in the current path from the DC power supply to the load side, and the control unit combines this detection voltage or detection current or detection voltage and detection current. High-speed ON / OFF control of the switch element so that any of the values becomes constant, and the ON / OFF control is performed with respect to the commercial AC power input including at least the range of 90V to 264V. By performing high-speed ON / OFF control of this switch element so that either the detection current or the combined value of the detection voltage and the detection current becomes a predetermined value determined by the operation of the operator or the control unit,
Achieves a wide range of commercial power supply voltage of 90 to 264V and a predetermined vibration level according to a wide range of operator settings. Furthermore, the hardness of the load, the mass, the degree of mechanical coupling between the load and the vibrating member, the frequency of contact, This makes it possible to prevent fluctuations in the vibration level due to fluctuations in commercial power supply voltage, temperature characteristics of the vibrator, and changes over time.
Further, the control unit performs low-speed ON / OFF control of the power converter at a period and time ratio longer than the ON / OFF period of the high-speed ON / OFF control, and the load in the high-speed ON / OFF control. By providing a filter having a cutoff frequency at a frequency lower than the center frequency of the low-speed ON / OFF control in the current detector and the voltage detector,
The device is made as simple as possible to reduce power consumption while enabling a wide range of operator-specified vibration levels.

Further, a DC power source that converts commercial AC power input into a DC voltage, a power converter that converts DC power output from the DC power source into AC, a vibrator that vibrates with AC power output from the power converter, and a vibration load In a vibration application apparatus including a vibration output unit connected to a vibrator for applying vibration to the vibrator and contacting a vibration load, and a control unit for controlling a DC power supply / power converter, A vibrator voltage detector is provided in parallel in a circuit or a vibrator current detector in series, and the control unit has a vibrator with a frequency in a certain range at a level equal to or higher than a certain value in the vibrator voltage detector or the vibrator current detector. By turning on the power converter from the OFF state when a signal appears,
Further, after the power converter is turned on from the OFF state, the control unit continues to turn on the power converter when the vibrator signal appears, and further the vibrator signal is detected or detected. When the power converter is in the OFF state by continuing to turn on the power converter for a certain period from the time when it disappears, the power converter side between the vibrator voltage detector or vibrator current detector and the power converter By providing a vibrator switch element that shuts off the circuit, the control unit further turns off the vibrator switch element when the power converter is OFF, and the vibrator switch element when a vibrator signal is detected By turning on
This makes it possible to perform start / stop control of vibration without using a complicated and high-grade photoelectric sensor or a separate foot pedal.

Also, immediately after the power converter is turned on or when the load fluctuates, the control unit starts vibration at a vibration level smaller than a predetermined vibration level determined by the operator, and the predetermined vibration determined by the operator By controlling the time to reach the level at a time longer than either the response time of the control system or the time of one cycle of the commercial power supply frequency, a transient large amplitude that occurs during startup, load fluctuation, and load contact It is possible to prevent this.
In addition, by using a piezoelectric vibrator as the vibrator, the above-described solution can be realized with a simpler and smaller circuit.
Further, by making the temporal change of the low-speed ON / OFF control frequency or the ON / OFF duty into a function set in advance or a function inputted from the outside, it is painful for the operator or those around the device. Or it reduces the discomfort or brings comfort.

As a general vibration application device including a material condensing device, an ultrasonic calculus removing device, and an ultrasonic cleaning device, a 100V specification product and a 220V specification product are separately manufactured to correspond to different power supply voltages in Japan or outside Japan. Although it is sold, the power supply input voltage is different, so that the problem of limitation of the country of use and the necessity of an external voltage converter is solved, and at the same time, the operator can set a wide range of vibration levels. Further, the vibration level can be kept constant against commercial power supply fluctuations, load fluctuations, vibrator temperature fluctuations and secular fluctuations.
In addition, the apparatus can be made as simple as possible to reduce power consumption while allowing a wide range of operator-specified vibration levels.
Further, it is possible to perform vibration start / stop control without using a complicated and high-grade photoelectric sensor or a separate foot pedal for starting and stopping vibration.
Further, it is possible to prevent a transient large amplitude that occurs at the time of start-up, load fluctuation, and load contact.
It also reduces the pain or discomfort of the operator or those who are in the vicinity of the device, or provides a feeling of comfort.

(Embodiment 1 of the invention)
A switch element is provided inside the DC power supply, a voltage detector is provided at the output of the DC power supply, a load current detector is provided in the current path to the vibrator, and this switch is set so that the control unit keeps this detection current or detection voltage constant. The element is controlled at high speed ON / OFF, and the ON / OFF control corresponds to a commercial AC power input including a range of at least 90V to 264V, and one of the detected currents is determined by an operator's operation or a control unit. The best mode of the present invention configured to satisfy the following values will be described with reference to FIG.
FIG. 6 is a configuration block diagram of a vibration application apparatus according to the present invention. In FIG. 6, 8 is a voltage detector, 9 is a current detector, 10 is a voltage detection amplifier (input voltage Vdc), 11 is a current detection amplifier (input current Iv), 12 is an operator adjustment input, and 13 is an operator input amplifier. (Output voltage Vs), 14 is an error amplifier (output voltage Ve), 15 is a switch element drive circuit (output voltage Vd), and 16 is a switch element. The device according to FIG. 6 operates as follows. In the following description, (1) and (2) indicate both cases of (1) and (2). In the present invention, either one of the voltage detector 8 and the current detector 9 may be provided, but both may be provided.
First, when the commercial power input to the commercial power input unit 4 increases (1) and (2) decreases, the output voltage of the voltage detector 8 and the input voltage Vdc of the voltage detection amplifier 10 increase (1) and (2). Try to decrease. In addition, when the load on the vibrator 2 is (1) decreased or (2) increased, the vibrator is (1) easy to vibrate, (2) it is difficult to vibrate, and the vibration speed and the vibrator current proportional thereto are ( 1) Increase / (2) decrease, and the input Iv of the current detector 9 and the current detection amplifier 11 increases (1) / (2) decreases. Then, the error amplifier 14 compares the output voltage Vs of the operator input amplifier reflecting the operator adjustment input 12 with Vdc and Iv, and when Vdc and Iv increase (1) and decrease (2), the output Ve becomes (1 ) Decrease, (2) Increase. Specifically, the output Ve operates, for example, as follows.

Here, the coefficients a, b, and Zi are appropriately determined positive constants. Both the voltage detector 8 and the current detector 9 may be provided, but it is assumed that b is present when there is no voltage detector 8, and Zi is zero when there is no current detector. The switch element drive circuit 15 is a circuit for driving the switch element with PWM and PFM at an appropriate frequency, and receives the output Ve of the error amplifier 14 and its duty D operates as follows.

The output voltage Vdc of the DC power supply 5 operates as shown in the following equation with the commercial power supply input voltage as Vac.

Further, assuming that the electromechanical transmission admittance of the vibrator is Yem, the vibration speed v (rms value) of the vibrator operates as follows.

The vibration speed is reflected in the current Iv of the vibrator which is an input to the current detector as in the following equation.

Kem is an energy conversion constant corresponding to the current of the vibrator per unit vibration speed, and is called an electromechanical conversion coefficient.
When a voltage detector is used to make the output voltage Vdc of the DC power supply constant according to Equations 1 to 5, Zi is set to zero and the operation is performed as shown in the following equation.

The second equation of this equation is approximated when the gain g of the error amplifier is increased. If the gain g of the error amplifier is increased, a stable output Vdc of the DC power supply 5 can be obtained against a large fluctuation of the commercial power input Vac.
Further, the vibration velocity v operates according to the following equation according to Equations 1 to 5.

By increasing the gain g of the error amplifier 14 by the second factor of Equation 7, the vibration speed v is set to a constant value proportional to the operator input voltage Vs with respect to the fluctuation of the electromechanical admittance Yem due to the commercial power input Vac and the load. It is possible to keep. In this case, it is a condition that the third factor of Equation 7 is close to 1. However, since the specification of the normal vibrator is preferentially determined over the specification of the circuit, the electromechanical conversion coefficient kem of the vibrator is determined according to the present invention. It cannot be designed as a parameter. Further, the electromechanical admittance Yem represents the load fluctuation itself. Therefore, the third factor of Equation 7 may be made close to 1 by reducing the gain b of the voltage detector amplifier and increasing the sensitivity Zi of the current detector.
Of course, in the best practice of the invention, if a voltage detector is not used, that is, if b is set to zero, Equation 7 becomes the following equation.

By increasing the gain g of the error amplifier 14 according to Equation 8, the fluctuation of the electromechanical conversion coefficient kem due to the secular change of the vibrator and the temperature change can be further reduced against the fluctuation of the electromechanical admittance Yem due to the commercial power input Vac and the load. The vibration speed v can be kept at a constant value proportional to the operator input voltage Vs even with respect to the fluctuation of the electromechanical admittance Yem.
In this way, it corresponds to a wide range of commercial power supply voltage of 90 to 264 V and vibration level setting by a wide range of operators, and further, the hardness of the load, the degree of mechanical coupling between the load and the vibration member, and the contact This makes it possible to prevent the vibration level from fluctuating due to fluctuations in frequency, fluctuations in commercial power supply voltage, temperature characteristics of the vibrator, and secular changes. In addition, not only the PWM method but also the PFM method can be used for controlling the DC power source, or a combination thereof can be used freely, so that the switching element in the DC power source 5 and the control element in the power converter 6 can withstand. It is possible to use an element with a small voltage and a safe operating area, and thus an element that is small, generates little heat, and is inexpensive. Further, the power converter uses the output voltage Vdc of the DC power supply 6 that is stably supplied by the DC power supply 6 without being affected by the difference or fluctuation of the commercial power supply and the fluctuation of the load, and is used as a positive feedback from the vibrator 2. This makes it possible to design a dedicated system for cooperative oscillation, and to maintain stable vibration for a long period of time without causing abnormal noise due to spurious vibrations or abnormal noise due to vibration level fluctuations. It is more preferable to use a signal from the current detector 9 for positive feedback from the vibrator 2 to the power converter 6.

(Embodiment 2 of the invention)
Next, the control unit performs low-speed ON / OFF control of the power converter at a cycle and time ratio longer than the ON / OFF period of the high-speed ON / OFF control, and the high-speed ON / OFF control By providing the load current detector and the voltage detector with a filter having a cutoff frequency at a frequency lower than the center frequency of the low-speed ON / OFF control, the low-speed ON / OFF control frequency or ON / OFF By making the temporal change of the duty of the function a preset function or a function input from the outside, the device can be made as small and compact as possible, while suppressing power consumption, enabling a wide range of operator-specified vibration levels, The best embodiment of the invention that reduces the pain or discomfort of the operator or those who are in the vicinity of the device, or provides comfort It described using FIGS. 7 to 9.

FIG. 7 is a block diagram showing the configuration of a vibration application apparatus that performs ON / OFF control of a power converter at a low frequency. Compared to FIG. 6, a low-frequency duty oscillator 17 is added, and its output signal is input to the power converter, and the power converter is turned ON / OFF by this signal. The output signal of the low frequency duty oscillator is shown in FIG. The low-frequency duty oscillator 17 is an oscillator that oscillates in a rectangular wave with a cycle longer than the time constant of the vibrator. The power converter is turned on during the ON period when the voltage is generated, and the power converter is turned off during the OFF period when the voltage is zero. To do. As a result, the envelope connecting the maximum value and the minimum value of the drive voltage waveform applied to the vibrator is as shown in the upper diagram of FIG. In the upper diagram, the ON period of the power converter oscillating with voltage is the ON period of FIG. 8, and the OFF period of the power converter not generating the voltage is the OFF period of FIG. Further, an envelope connecting the maximum value and the minimum value of the drive current flowing through the vibrator is as shown in the lower diagram of FIG. The drive current gradually increases during the ON period of the power converter, and the drive current gradually decreases and attenuates during the OFF period of the power converter. When the drive current operates at the resonance frequency of the vibrator, most of the drive current is an oscillating current having substantially the same phase as that of the drive voltage, and is almost proportional and similar to the mechanical vibration speed of the vibrator. Therefore, when operating at the resonance frequency, the drive current waveform can be regarded as substantially the same as the vibration velocity waveform of the vibrating body. When the vibrator is driven by a piezoelectric body, a part of the driving current flows as a dielectric current of the piezoelectric body. This has a phase of 90 degrees with respect to the drive voltage, and the drive current slightly advances with respect to the drive voltage at the resonance frequency at which the maximum vibration speed can be obtained.
In this way, the vibration velocity waveform of the vibrator takes an envelope like the drive current waveform shown in the lower diagram of FIG. That is, the maximum vibration speed can be increased with respect to the average vibration speed. This is nothing but to give low-frequency modulation to the vibrator. For example, in the case of a dental material condensing device, the vibration plate 3 is in contact with a dental material holding tool holding a porcelain built-up metal crown as a load while vibrating. The material holding device leaves the diaphragm and the diaphragm vibrates without load until it comes into contact again. The contact timing is more likely to be established when the amplitude of the envelope in the lower diagram of FIG. 9 is larger. That is, the time when the amplitude of the envelope is small does not contribute to driving the load. This means that the drive efficiency of the load increases when the vibrator is modulated. On the other hand, in the case of continuous driving without modulation, the vibrator maintains the maximum vibration during the period from when the load comes in contact to when it is separated and then comes into contact again, which is inefficient. This is not limited to dental material condensing devices, but can be applied to all vibration application devices that drive a contact load.

That is, the load can be efficiently driven by applying the modulation.
Further, in the case of continuous driving, the period of driving with no load is long, but the state of operating at the maximum vibration speed without load for the vibrator is close to the limit vibration speed of the vibrator. The state will be long. All devices are usually designed, manufactured and used to ensure maximum operation while maintaining a certain safe operating range with respect to all of their allowable limits. You are designing. In the case of continuous driving, not only unnecessary power is applied to the vibrator to accelerate the deterioration of the vibrator, but also the temperature of the equipment rises and unnecessary ultrasonic noise is generated in the case of non-ultrasonic operation. Will affect. In addition, a large and expensive power converter, DC power source, and commercial power source are required, and energy consumption is large. A vibrator designed to the limit of the tolerance limits deterioration and aging.
In addition, this phenomenon is remarkable in the case of an application for driving a diaphragm like the dental material condenser Ceracon 2, but there are many resonance modes in the diaphragm, which are caused by random contact of the load. When low-frequency waves are adapted to the resonance mode of the diaphragm (when the frequency approaches, it is easy to vibrate), low-frequency energy accumulates in the diaphragm, and the resonance frequency of the vibrator becomes the ultrasonic region. Although it should be aiming for silent operation, strong low-frequency abnormal noise such as howling that occurs in so-called acoustic equipment tends to occur.

As shown in FIG. 3, the same configuration, operation, and effect as the modulation are also brought about when the DC power source is converted by the half-wave rectification of the commercial power frequency in the dental material condensing device Ceracon 2. . However, this half-wave rectifier circuit cannot be used in the vibration application apparatus corresponding to the commercial power supply voltage of 90 V to 264 V and the vibration level setting operation by the operator shown in FIG. Further, the frequency is limited to the commercial power supply frequency, and the duty is limited to 50%. A vibrator has a time constant related to starting and stopping. This is the time constant of the curve increasing in the ON period and the curve decaying in the OFF period (time until the amplitude becomes 1 / e) in the envelope of the drive current, that is, the vibration velocity shown in the lower diagram of FIG. Is unique to the vibrator and its resonance frequency, and is not necessarily a time constant corresponding to the 16.7 msec to 20 msec OFF period of 50% duty of the commercial frequency.
In the present invention, the oscillation frequency of the low-frequency oscillator 17 may be introduced from the commercial power supply input unit 4 when the modulation is limited to the commercial power supply frequency by half-wave rectification such as the ceramic converter 2. However, this method has a limited modulation frequency. As the best mode of the present invention, a low-frequency oscillator having an oscillation mechanism that is independent from both the commercial power supply frequency and the resonance frequency of the vibrator, and the duty can be arbitrarily designed and set. For example, it is very suitable to be constituted by a microcomputer.

By adopting a low-frequency oscillator that can arbitrarily design and set the modulation frequency and modulation duty of the modulation in this way, it is possible to select the modulation frequency and modulation duty that optimally correspond to the time constant and resonance frequency of the vibrator. . Also, in the case of a dental material condensing device, various types of dental material holders are used, and sometimes the dental model becomes a load, and the modulation frequency and modulation duty are arbitrarily set accordingly. By doing so, the load can always be driven with the optimum efficiency and the optimum feeling. Even when the patient's teeth become a load, as in the case of an ultrasonic calculus removal device, this modulation frequency and modulation duty can be set appropriately to not only provide the teeth with optimal driving, but also to the patient. And driving with reduced discomfort can be realized.
Furthermore, it is also very suitable to make the temporal change of the low-speed ON / OFF control frequency or the ON / OFF duty as a preset function, for example, a function of a sound waveform of water or a waveform of music. is there. It is also very suitable to use a function such as music input from the outside. Since this low frequency modulation induces vibration of the modulation frequency in the vibrator and the vibration output section and load connected thereto, it is possible to bring about a change in sound by these functions. By making these sounds mellow, birdsongs, internal or externally input music, the pain or discomfort of the operator or those around the device, especially patients in dentistry, is reduced or brought to a comfortable feeling Is.
Furthermore, as an embodiment of the present invention, it is preferable that the current detector 9 or the voltage detector 8 is provided with a filter having a cutoff frequency at a frequency lower than the modulation frequency. This is to prevent the influence of the modulation from adversely affecting the output control of the DC power supply by the feedback of the drive voltage or drive current when the vibration is modulated.

(Embodiment 3 of the invention)
Next, a DC power source that converts commercial AC power input into DC voltage, a power converter that converts DC power output from the DC power source into AC, a vibrator that vibrates with AC power output from the power converter, and vibration In a vibration application apparatus including a vibration output unit connected to a vibrator to apply vibration to a load and contacting the vibratory load, and a control unit for controlling a DC power supply / power converter, the vibrator and A vibrator voltage detector is provided in parallel with the electric circuit or a vibrator current detector is provided in series, and the control unit vibrates the vibrator voltage detector or vibrator current detector with a frequency within a certain range at a level higher than a certain value. By turning on the power converter from the OFF state when the child signal appears,
Further, after the power converter is turned on from the OFF state, the control unit continues to turn on the power converter when the vibrator signal appears, and further the vibrator signal is detected or detected. When the power converter is in the OFF state by continuing to turn on the power converter for a certain period from the time when it disappears, the power converter side between the vibrator voltage detector or vibrator current detector and the power converter By providing a vibrator switch element that shuts off the circuit, the control unit further turns off the vibrator switch element when the power converter is OFF, and the vibrator switch element when a vibrator signal is detected By turning on
A preferred embodiment of the present invention that performs start / stop control of vibration without using a complicated and expensive photoelectric sensor or a separate foot pedal will be described with reference to FIGS.
FIG. 10 is a diagram showing an impact (hit) that triggers the start-up, in which a dental material holder B holding a metal crown A made of porcelain is brought into contact with a diaphragm 3 of a dental material condensing device that imitates a ceramic contact 2 The generation | occurrence | production and the point X of the impact which generate | occur | produce at the moment made to show are shown. Even if it is called an impact, even a very weak contact can be detected. Here, this is called hit detection.

FIG. 11 is a configuration block diagram of hit detection, in which the diaphragm 3 and the vibrator 2 are extracted from the dental material condensing apparatus simulating the ceramic condenser 2, and related circuit blocks are extracted and drawn. In FIG. 11, 18 is a piezoelectric body. The piezoelectric body 18 is a state in which two piezoelectric bodies are put together with an intermediate electrode in between and end face electrodes are attached to the top and bottom. Furthermore, the vibrator 2 is configured by combining aluminum blocks 18 and 19 on the upper and lower sides of the piezoelectric body 18. Therefore, the vibrator 2 is a piezoelectric vibrator. These are all bolt-clamped Langevin type piezoelectric vibrators having a circular cross section and fixed by bolts provided inside. In many cases, the two piezoelectric bodies 18 have a two-terminal structure in which two end face electrodes are electrically connected and only the intermediate electrode is insulated. However, in FIG. It is drawn to connect. An external circuit as shown in FIG. 11 is connected to the piezoelectric vibrator having such a two-terminal structure. Reference numeral 20 denotes a vibrator voltage detector using a resistor having a large resistance value, and reference numeral 21 denotes a vibrator current detector using a resistor having a small resistance value. Various other configurations of the current detector and voltage detector are conceivable. For example, the voltage detector 8 and the current detector 9 may also be used. 22 is a transducer voltage detection amplifier, 23 is a transducer current detection amplifier, 7 is a control unit, and 6 is a power converter 6 which is redrawn in a voltage source expression in which a rectangular wave waveform is symbolized. Reference numeral 24 denotes a piezoelectric vibrator opening switch element. Each component block is connected by wiring as shown in FIG. 11, and a part of the blocks is represented by an arrow means a signal.

The operation of hit detection configured as described above will be described below. First, when an impact X is applied to the diaphragm 3 while the power converter 6 shown in FIG. 11 is OFF, the piezoelectric body 18 is moved in the vertical direction via the vibrator 2 connected to the diaphragm 3. Tensile / compressive stress is generated. In the case of a piezoelectric body of the type used in a bolted Langevin type piezoelectric vibrator, it is polarized in the vertical direction with respect to the tensile and compressive stress in the vertical direction. Since the two piezoelectric bodies are arranged in opposite polarities through the intermediate electrode, polarization charges are generated in the end face electrode and the intermediate electrode. This polarization charge flows through the resistance of the vibrator voltage detector 20 to generate a voltage, which becomes an input to the vibrator voltage detection amplifier 22, that is, a vibrator signal. Alternatively, this polarization charge flows through the resistance of the transducer current detector 21 to generate a voltage, and becomes an input to the transducer current detection amplifier 23. A hit detection waveform 25 which is a transducer signal is shown by a solid line in FIG.
When a transducer signal is generated and a signal of a certain value or more is output from the transducer voltage detection amplifier 22 or the transducer current detection amplifier 23, the control unit 7 turns on the power converter 6 and starts driving the transducer 2. Is.

  Further, the control unit 7 turns on the power converter 6 and then turns on the power converter 6 after continuing to turn on the power converter 6 for a certain period of time designated by the operator or defined in the device specifications. is there. Alternatively, the control unit 7 keeps turning on the power converter 6 as long as the operator applies the dental material holding tool B to the diaphragm 3, that is, as long as the vibrator signal is detected, and the operator keeps the dental material. When the holding device B is separated from the diaphragm 3, that is, when the vibrator signal is no longer detected, the power converter 6 is turned off at that time or after a certain time has elapsed from that time, the power converter 6 Is to turn off. In this case, the transducer voltage detector or transducer current detector should also have a signal reflecting the drive voltage and drive current in addition to the transducer signal. Since the drive current has a different frequency band, the vibrator voltage detector 20, the vibrator current detector 21, the vibrator voltage detection amplifier 22, and the vibrator current detection amplifier 23 are provided with a filter so that a signal based on the drive voltage or the drive current is output. It is preferable to remove. Since the drive frequency of the drive voltage and drive current is the resonance frequency of the vibrator, this filter is more preferably a band elimination filter that removes only the drive frequency component.

Furthermore, as shown by a broken line 26 in FIG. 12, when the vibrator starts vibration, that is, when the power converter 6 is OFF, the piezoelectric body is very A small noise current 26 due to minute vibrations and temperature changes is generated in this case. When the sensitivity of hit detection is increased, these currents are detected as piezoelectric signals when there is no impact input X, and the power converter 6 The malfunction that turns ON is likely to occur. Since the output impedance of the power converter 6 that is turned off flows as a load on the piezoelectric body, the noise current 26 flows as a best mode of the present invention to eliminate the noise current 26. A piezoelectric vibrator opening switch element 24 is provided between the piezoelectric bodies, and the control section 7 turns on the piezoelectric vibrator opening switch element 24 when the power converter is turned on by detecting the piezoelectric signal. .
By detecting hits in this way and turning vibrations on and off, even operators with full hands can use the vibration application device itself without extra accessories such as a foot pedal or extra effort. The device can be easily turned ON / OFF.

(Embodiment 4 of the Invention)
Next, immediately after the power converter is turned on or when the load fluctuates, the control unit starts to vibrate at a vibration level smaller than a predetermined vibration level determined by the operator. An embodiment in which the time to reach the vibration level is controlled in a longer time than both the response time of the control system and the time of one cycle of the commercial power supply frequency will be described below.
In the present invention, as described in the first embodiment, it is possible to drive the vibration application device with a wide commercial power supply voltage input of 90 V to 264 V and a specified vibration level specified by an operator in a wide range. Accordingly, the control unit 7 can gradually increase the vibration level from the vibration level lower than the specified vibration level at the time of activation so as to reach the specified vibration level with a certain time. For this purpose, it is preferable that the control unit 7 is provided with a timer circuit having a time constant, or the vibration level is gradually increased by software by the control unit 7 using a microcomputer.
In this way, it is possible to prevent a transient large amplitude occurring at the time of start-up, load fluctuation, or load contact. That is, since it can be used without exceeding the specified vibration level and the allowable vibration level, the load and the device are not damaged.

(Embodiment 5 of the invention)
As described in the third embodiment, the vibration application device according to the present invention described in the first to fourth embodiments can be realized more compactly and simply by using the vibrator as a piezoelectric vibrator.

The present invention can deal with a wide range of commercial power inputs and a wide range of operator-set vibration levels with the same specification model for vibration application devices, particularly vibration application devices using a piezoelectric material, It can be used for vibration application equipment. Also, by using modulation, a large vibration effect can be obtained with a smaller vibrator, contributing to downsizing and energy saving. In addition, it can be started / stopped by the operation itself to achieve the purpose of the vibration application device, without any accessories or additional parts such as foot pedals, infrared pyroelectric sensors, etc. Think of things. Further, since the vibration can be used without exceeding the specified vibration level or the allowable vibration level at the time of start-up, the load or the device is not damaged.
The present invention can be suitably used particularly for an ultrasonic cleaning device, a vibration cutting device, a vibration surface treatment device, a material stirring device, and a material condensing device. In particular, it is suitable for a dental vibration application apparatus and a dental vibration application apparatus using a piezoelectric body. Specifically, it is suitable for a dental ultrasonic cleaning device, an ultrasonic calculus removing device, a dental vibration cutting device, a dental vibration surface treatment device, a dental material stirring device, and a dental material condensing device. .

Operational schematic diagram of a conventional dental material condensing device Ceracon 2 Block diagram of Ceracon 2 Drive voltage waveform and drive current waveform of power converter of Ceracon 2 Envelope of driving voltage waveform and driving current waveform of power converter of Ceracon 2 Voltage waveform of power converter by general PWM control Configuration block diagram of vibration application apparatus according to the present invention Diagram for ON / OFF control of power converter at low frequency Signal to turn on / off power converter at low frequency Envelope of drive voltage and drive current that is ON / OFF controlled at low frequency Diagram showing impact that triggers startup Block diagram of hit detection Hit detection waveform

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceracon 2 main body 2 Bolt tightening Langevin type vibrator | oscillator which is a vibrator | oscillator of Ceracon 2 3 Diaphragm which is a vibration output part of Ceracon 2 Commercial power supply input part 5 DC power supply 6 Power converter 7 Control part 8 Voltage detector 9 Current Detector 10 Voltage detection amplifier 11 Current detection amplifier 12 Operator adjustment input 13 Operator input amplifier 14 Error amplifier 15 Switch element drive circuit 16 Switch element 17 Low frequency oscillator 18 Piezoelectric body 19 Aluminum block 20 Vibrator voltage detector 21 Vibrator Current detector 22 Transducer voltage detection amplifier 23 Transducer current detection amplifier 24 Piezoelectric transducer opening switch element 25 Hit detection waveform 26 Noise current
A Porcelain built-up metal crown
B Dental material holder X The point of impact generated at the moment when the dental material holder B holding the ceramic crown B is brought into contact with the diaphragm 3

Claims (7)

A DC power source that converts commercial AC power input into DC voltage, a power converter that converts DC power output from the DC power source into AC, a vibrator that vibrates with AC power output from the power converter, and a vibration that vibrates In a vibration application device including a vibration output unit for connecting to a vibrator and applying contact with a vibration load, and a control unit for controlling a DC power supply / power converter, A transducer voltage detector or a transducer current detector in series is provided in parallel, and the control unit sends a transducer signal of a certain range of frequencies at a level equal to or higher than a certain value to the transducer voltage detector or transducer current detector. A vibration application device characterized by turning on the power converter from the OFF state when it appears. 2. The vibration application device according to claim 1, wherein after the power converter is turned on from the OFF state, the control unit continues to turn on the power converter when the vibrator signal appears. 3. 3. The vibration application apparatus according to claim 1, wherein the power converter is continuously turned on for a certain period from when the vibrator signal is detected or no longer detected. When the power converter is in an OFF state, a vibrator switch element is provided between the vibrator voltage detector or the vibrator current detector and the power converter to cut off the circuit on the power converter side. Item 4. The vibration application device according to Items 1 to 3. 5. The vibration application device according to claim 4, wherein the control unit turns off the vibrator switch element when the power converter is in the OFF state, and turns on the vibrator switch element when the vibrator signal is detected. . Immediately after turning on the power converter or when the load fluctuates, the control unit starts to vibrate at a vibration level smaller than the predetermined vibration level determined by the operator, and reaches the predetermined vibration level determined by the operator. The vibration application apparatus according to claim 1, wherein the time until reaching the control time is controlled by a time longer than any one of a response time of the control system and a time of one cycle of the commercial power supply frequency. The vibration application apparatus according to claim 1, wherein the vibrator is a piezoelectric vibrator.