JPS60172376A - Atomizing device - Google Patents

Abstract

PURPOSE:To obtain always a stabilized and specified amt. to be atomized by providing a pressure detector in the pressurized chamber of an atomizer, and controlling the output signal to a specified value. CONSTITUTION:A pressure detector 16 is provided at a position opposing to a nozzle part 5 in a pressurized chamber 2. In this case, a piezoelectric element which is polarized in the thicknesswise direction is used as the detector. One surface of the detector is bonded to a body 1 through an electrode, and a lead wire 17 is taken out from an electron on the other surface side. By this constitution, the pressure change of the liquid in the pressurized chamber 2 due to the action of a nozzle part 5 oscillated by a piezoelectric element 6 is caugth by the pressure detector 16, and the electric power to be impressed is regulated to a specified value with an operating part. Accordingly, a specified amt. to be atomized can be stably obtained regardless of the change and deterioration in characteristics due to the environmental changes in surrounding temps., etc. and aged deterioration.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid atomization device that uses a piezoelectric element to atomize liquid fuel such as kerosene or light oil, water, medicinal solution, stirrup fluid, etc.

Conventional configurations and their problems Various types of liquid atomization devices have been proposed in the past, and many of them use piezoelectric elements.

In recent years, an atomizer having a structure as shown in FIG. 1 has been proposed as an atomizer that has a small driving power, is compact, and can obtain an atomization amount of 20 cc/lII+1 or more. The body 1 of the atomizer includes a pressurized chamber 2 filled with liquid, and the liquid enters the pressurized chamber 2 through a supply pipe 3, and during the atomizing operation, the gas discharge pipe 4 is filled halfway. It will be done. 5
A nozzle portion is arranged facing one side of the pressurizing chamber 2, and its outer periphery is joined to the body 1. In the center of the nozzle part 5, there is a fine hole (50 to 100 μm) for ejecting M droplets.
It's stuck open. Furthermore, the nozzle part 5 has a thickness of 0, 5
~llffil outer diameter 10~20mm (0 annular pressure'
Its child 6 is joined. This piezoelectric element 6 is a piezoelectric ceramic polarized in the thickness direction, and has electrodes on the surface to be joined to the nozzle and on the opposite surface. 7.

Reference numeral 8 denotes a cross-body wire for transmitting a drive signal to the piezoelectric element 6, which is connected to one electrode of the piezoelectric element and the body 1, respectively. When the mechanical vibration of the piezoelectric element 6 is excited by the drive signal, the nozzle part 5 is also energized and vibrated, so that the pressure chamber 2
A pressure increase oscillates inside the chamber, and as a result, the liquid becomes atomized particles 9 and is discharged. 010 is a fan for generating negative pressure, which pulls up the liquid from the liquid tank 11 through the supply pipe 3 and supplies it to the pressurized chamber. 2 and the exhaust pipe 4 are filled halfway with liquid. According to this configuration, the power consumption of the piezoelectric element is several hundred milliwatts, and atomization of more than 200C/TMn is achieved. As a driving method for this atomizer, the method shown in Figs. 2 and 3 is used. There is. In FIG. 2, an oscillation signal of a predetermined period is applied from an oscillator 12 to an amplifier 13 to drive a piezoelectric element 6 configured as an atomizer.

In FIG. 3, the current flowing through the piezoelectric element is detected by a current detector 14 and fed back to the amplifier 13 via a bandpass filter 15 to cause self-oscillation. In the configuration shown in FIG. 3, in order to continue oscillation at the resonance point of the piezoelectric element where the liquid is efficiently atomized, a bandpass filter is arranged to suppress oscillation in spurious mode.

However, the above-mentioned conventional atomization devices had various drawbacks. The temperature characteristics of an atomizer that incorporates all piezoelectric elements include fluctuations in the resonance point, as shown in Figure 4. However, in the method shown in Figure 2, the oscillation frequency is determined by detecting the temperature of the piezoelectric element itself. corrections had to be made. but,
It has been very difficult to detect the temperature of piezoelectric elements.

In addition, with the method shown in Figure 3, frequency tracking is also extremely difficult when the resonance characteristic of the piezoelectric element has a low Q. Furthermore, Figure 5 shows the impedance looseness of the conventional atomizer. As shown, loop 1 is in a state where the pressurizing chamber is empty, and loop 2 is in a state filled with liquid. As can be seen from this figure, the capacitive characteristics are particularly strong during the atomization operation. In other words, the effect of braking impedance is large, including temperature characteristics,
It was difficult to detect an electrical signal proportional to the amount of spray.

Therefore, in the past, a method was adopted in which the gain of the amplifier was adjusted to match the spray amount characteristics of the atomizer, and furthermore, the gain was changed according to a preset characteristic in response to temperature changes. However, if the bond between the nozzle portion and the piezoelectric element or the bond between the nozzle portion and the body deteriorates due to environmental changes, changes over time, etc., a predetermined amount of spray cannot be obtained using conventional correction methods.

Purpose of the Invention The present invention eliminates such conventional drawbacks, and provides a fog that can obtain a predetermined amount of spray even when the characteristics change due to environmental changes such as ambient temperature, changes over time, or deterioration. The purpose is to provide a

Structure of the Invention In order to achieve this object, the present invention provides a pressure sensor in the pressurizing chamber 2 in addition to the structure of the atomizer shown in the conventional example. A drive unit that drives the piezoelectric element 6 connected to the nozzle unit receives the signal from the pressure sensor.

With this configuration, the pressure sensor detects fluctuations in the liquid pressure in the pressurizing chamber due to the action of the nozzle section excited by the piezoelectric element 6, and the drive section adjusts the applied power so that it reaches a predetermined value. conduct. As a result, a predetermined amount of spray is always obtained.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. 1st
Components with the same numbers as those in the drawings have the same functions. The pressure detector 16 is provided in the pressurizing chamber 2 at a position facing the nozzle portion 5 . In Figure 6, a piezoelectric element polarized in the thickness direction is used as a pressure sensor.
One side thereof is joined to the body 1 via an electrode, and a conductive wire 17 comes out from the electrode formed on the other side.

FIG. 7 shows the operation of the pressure sensor. Components with the same numbers as in FIG. 6 are components having the same functions. In the figure, the conductive wires 7 and 17 are omitted.The nozzle portion 5 undergoes a deflection movement as shown in the figure due to mechanical strain caused by the radial vibration of the piezoelectric element 6. This deflection causes pressure propagation within the pressurizing chamber 2 as shown. This pressure fluctuation becomes a mechanical vibration in the pressure sensor 16 and is further converted into an electrical signal, and the amount of spray droplets is determined by the pressure increase value in the pressurizing chamber 2. Therefore, if the pressure detector 16 is arranged at a position where pressure fluctuations contributing to spray can be detected, that is, at a position facing the vibrating nozzle part, and the detection signal is controlled to a predetermined value, the amount of spray can be increased. control is possible.

FIG. 8 shows an embodiment of the driving device according to the present invention, in which the driving section 17 includes an oscillator 12. It consists of an amplifier 13 and a gain adjuster 1. The signal from the pressure sensor 16 is input to a gain adjuster in the drive section, and the gain of the amplifier 13 is controlled to a predetermined value. In other words, the power applied to the piezoelectric coil 6 that energizes the nozzle section is adjusted so that a predetermined amount of spray is obtained.

By using the pressure sensor configuration of the present invention and controlling the applied power to the drive circuit that tracks the frequency of the resonance point as shown in Figure 3, even more efficient atomization operation is achieved. can do.

Furthermore, it is possible to determine whether or not the pressurized chamber is filled with liquid by determining the fluctuation range of the pressure sensor. That is, since it is possible to distinguish between air and liquid, it is also possible to completely suppress damage caused by empty vibration of the nozzle part.

Effects of the Invention According to the atomizing device of the present invention, a pressure sensor is installed in the pressurizing chamber of the atomizer that has been proposed in the past and has a unique configuration that allows a large amount of spray to be obtained with a small amount of power. By controlling the output signal to a predetermined value, it is possible to compensate for variations in the characteristics of the atomizer due to environmental changes or changes over time, and it is possible to stably atomize a predetermined amount of spray.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a conventional atomizer, Fig. 2 is a block diagram of a drive device of a conventional atomizer, Fig. 3 is a block diagram of another drive device of a conventional atomizer, and Fig. 4 5 is an impedance loose diagram of the atomizer, FIG. 6 is a sectional view of the main part of an embodiment of the atomizer of the present invention, and FIG. 7 is a 1π degree characteristic diagram of the resonance frequency of the atomizer. 8 is a diagram showing the operation of the atomization device of the present invention.
The figure shows an embodiment of the atomization device of the present invention. 1... Body, 2... Old pressurization chamber, 3...
...Liquid supply section, 5...Nozzle section, 6...
... Piezoelectric vibrator, 16 ... Pressure detector, 17
・Old drive unit. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2 Figure 4 Figure 5 Figure 7Fl Figure 6 7

Claims (2)

[Claims] (1) A body including a pressurizing chamber filled with liquid, a supply section for supplying liquid to the pressurizing chamber, a nozzle section having a nozzle facing the pressurizing chamber, and the nozzle. a piezoelectric vibrator that vibrates the nozzle by energizing the piezoelectric vibrator;
A device comprising a pressure sensor provided in the pressurizing chamber, and a drive section that receives a signal from the pressure sensor and applies a drive signal to the piezoelectric vibrator. (2) The atomization device according to claim 1, wherein the pressure detector is provided in the pressurizing chamber at a position facing the nozzle portion.