JPH0373342B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a liquid atomization device that atomizes liquid fuel such as kerosene or light oil, water, medicinal solution, recording liquid, etc. using an electric vibrator. .

Prior Art A conventional technology for tracking a mechanical resonance point where an atomizer operates efficiently is disclosed in Japanese Patent Application Laid-Open No. 154159/1983.

Problems to be Solved by the Invention In conventional atomizers, it was possible to track mechanical resonance points as long as the characteristics of the atomizer itself did not change over time. During the repetition, a change in characteristics occurred, and the mechanical resonance point of the atomizer itself shifted to a lower frequency side. but,
The equivalent capacity of the atomizer was also becoming smaller. Therefore, when calculating from the following equation in the conventional example, the oscillation frequency becomes high, and there is a problem that it cannot be said that the mechanical resonance point is reliably tracked.

f = 1/2π L (C _T +C ₁ ) or f = 1/2π L (C _T C ₂ ) Therefore, the present invention reliably maintains the mechanical resonance point of the atomizer even if the mechanical resonance point of the atomizer shifts due to changes over time, etc. The aim is to provide a drive device that can track the object.

Means for Solving the Problems A nozzle having a body including a pressurized chamber filled with liquid, a supply section for supplying liquid to the pressurized chamber, and a nozzle provided facing the pressurized chamber. an atomizer comprising a part, an electric vibrator that energizes the nozzle to vibrate the nozzle, and an electrode part that detects mechanical strain of the electric vibrator; A phase shifter that shifts the phase of a strain detection signal or a drive signal to the electric vibrator, and a mixture that adds the output signal of the phase shifter and the strain detection signal or drive signal that does not go through the phase shifter. an amplifying section that amplifies the signal of the mixing section;
An atomizer driving device is constituted by a driving section that transmits a signal from the amplifying section to the electric vibrator.

Effect In the above-mentioned atomizer configuration, looking at the frequency characteristics of the phase difference between the drive voltage signal to the electric vibrator and the strain detection signal, the phase difference is π at the mechanical resonance point where the amount of atomization is maximum. /2. Therefore, if either of the above-mentioned signals is phase-shifted by π/2 and added to the other original signal, its frequency characteristics will exhibit a maximum value at the above-mentioned mechanical resonance point. Therefore, if this added signal is fed back to the amplification section, the predetermined frequency, that is,
A self-oscillating system that oscillates at a mechanical resonance point can be constructed.

Embodiment First, FIG. 2 shows the configuration of an atomizer. A body 2 including a pressurized chamber 1 filled with liquid is fixed to a mounting plate 4 with screws 3. Liquid is supplied through pipe 5
The gas enters the pressurized chamber 1 through the gas discharge pipe 6, and is filled to the middle of the gas discharge pipe 6 during the atomization operation. Reference numeral 7 denotes a nozzle portion facing one side of the pressurizing chamber 1, and its outer periphery is joined to the body 2. A spherical protrusion 8 having a fine hole for ejecting droplets is formed in the center of the nozzle portion 7 . Further, the nozzle portion 7 includes an annular electric vibrator, here a piezoelectric element 9.
is installed. This piezoelectric element 9 is a piezoelectric ceramic polarized in the thickness direction, and has electrodes on the joint surface with the nozzle and the opposite surface. 10 is a lead wire that transmits a drive signal to the piezoelectric element 9. One side is soldered to one electrode surface of the piezoelectric element 9, and the other side is connected to the body 2 with screws 11. When the mechanical vibration of the piezoelectric element 9 is excited by the drive signal, the nozzle part 7 is also energized and vibrates, and as a result, the liquid in the pressurizing chamber 1 is ejected as atomized particles 12. A signal detection lead from the electrode part that detects the voltage generated by the strain of the measure.
It is formed on one electrode side of the piezoelectric element.

Next, FIG. 3 shows the configuration of an electrode section for strain voltage detection. Components with the same numbers as in FIG. 2 have the same functions. 2 in Figure 3 is 1 a-
FIG. 14 is an electrode section for drive signals, and 15 is an electrode section for strain voltage detection.
Reference numeral 16 denotes an electrode section formed between each of the electrode sections 14 and 15. By making this electrode section the same potential as 17 which is paired with the electrode section 14 for drive signal transmission, the drive signal and strain detection signal can be transmitted. Electrical interference between the two can be significantly reduced. In the figure, a conductive wire that brings 16 and 17 to the same potential is not shown. Reference numeral 18 indicates a bonding layer between the electrode section 17 and the nozzle section 7.

Next, FIG. 1 shows a block diagram of the present invention. Components with the same numbers as in FIGS. 2 and 3 have the same functions. 19 is a phase shifter that shifts the drive signal of the piezoelectric element 9; 20 is a mixer that adds the output signal of the phase shifter and the signal of the strain detection electrode 15; and 21 is a mixer that adds the output signal of the mixer 20. The amplifying section 22 is a driving section that transmits a driving signal to the piezoelectric element. The example in FIG. 1 is a case where the drive signal is phase-shifted, but a similar block configuration will be obtained when the strain detection signal is phase-shifted. The phase relationship is explained in detail in Figure 4, but if one of the drive signal or the distortion detection signal is phase-shifted and added to the other original signal, self-oscillation will occur at the point where the added signal is maximum in the frequency characteristics. continues.

FIG. 4 shows the frequency characteristics of each signal of the atomizer, and 1 in FIG. 4 shows the frequency characteristics of the spray amount and the phase difference between the piezoelectric element drive signal and the strain detection signal. At the frequency frm at which the spray amount is maximum, the phase difference is just π/2. Here, at the mechanical resonance point where the spray amount is maximum, the vibration speed and the drive voltage signal are in phase, and the vibration speed is the time differential of the displacement of the piezoelectric element. Further, the strain voltage is mainly generated by the strain rate, which is the position differential of the displacement. Therefore, the drive voltage, which is in phase with the vibration velocity, which is the time differential of displacement, and the strain voltage are deviated by π/2. Further, 2 in FIG. 4 shows the frequency characteristics of the drive current of the piezoelectric element and the strain detection voltage. fre and fare in the figure are the electrical resonance point and the electrical anti-resonance point. The peak of the detection voltage is
It is shifted toward the electrical anti-resonance point rather than the mechanical resonance point. The characteristics shown in FIG. 4 are obtained when the drive voltage is kept constant.

Based on the characteristics shown in Figure 4, it is necessary to divide the drive voltage and strain detection voltage to a predetermined level by dividing the resistance, etc., and mix by shifting the phase by π/2 as shown in the system diagram shown in Figure 1. For example, a voltage characteristic that is maximum at the mechanical resonance point can be obtained.

FIG. 5 is a specific circuit diagram of the present invention. Components with the same numbers as in the previous figure are components having the same functions. The amplifying section 21 includes resistors 23, 24, 25,
26, 27, 28, 29 and capacitor 30
and transistors 31, 32, 33, and 34. The switching signal that is the output of the amplifier section 21 is transmitted to the piezoelectric element 9 via a capacitor 35, a pulse transformer 36, and an inductor 37. The inductor 37 forms a tank circuit with the capacitance of the piezoelectric element. capacitor 38
is inserted in parallel with the piezoelectric element to perform some crosstalk compensation. The driving voltage is divided by resistors 39 and 40, and resistors 41, 42, 43 and capacitor 4
The drive signal is phase-shifted via a phase shifter 19 consisting of 4 and 45. In addition, the strain detection signal is transmitted by the resistor 4
The pressure is divided by 6 and 47. The capacitor 48 is for reducing high frequencies and the like. The respective signals are transmitted to the mixing section 20 via capacitors 49 and 50. The capacitor 51 includes a piezoelectric element portion,
This is for connecting reference potentials of other circuit sections. The mixing section 20 includes resistors 52, 53, 54, 5
5, capacitors 56, 57, transistor 5
It consists of 8. 59 is a phase shift section inserted to continue self-oscillation in this specific circuit example,
Resistors 60, 61, 62, 63 and capacitor 6
4 and a transistor 65. A signal is transmitted from the mixing section via a capacitor 66, and a signal is transmitted from the phase shift section 59 via a capacitor 67 to the amplifier section.

Effects of the Invention According to the atomizer drive device of the present invention, even if the frequency characteristics of the atomizer change due to changes over time, etc., it is possible to reliably track the mechanical resonance point where maximum atomization can be obtained efficiently, and to maintain stable Atomization operation can be achieved.

[Brief explanation of drawings]

Fig. 1 is a block configuration diagram showing an embodiment of the present invention, Fig. 2 is a sectional view of the atomizer of the present invention, and Fig. 3 is a view showing the electrode part of the atomizer of the present invention (1 is a top view). figure,
2 is a sectional view), FIG. 4 is a frequency characteristic diagram of spray amount, phase difference, drive current, and detection voltage, and FIG. 5 is a specific circuit diagram of the present invention. 1... Pressurization chamber, 2... Body, 3... Supply section, 7... Nozzle section, 9... Piezoelectric element, 15...
Strain detection electrode section, 19...phase shift section, 20...mixing section, 21...amplification section, 22...drive section.

Claims (1)

[Claims] 1. A body equipped with a pressurized chamber filled with liquid;
a supply unit for supplying liquid to the pressurizing chamber; a nozzle unit having a nozzle facing the pressurizing chamber; and an electric vibrator that biases the nozzle unit and vibrates the nozzle. and an electrode section for detecting mechanical strain of the electric vibrator;
A phase shifter that shifts the phase of a strain detection signal from the electrode section or a drive signal to the electric vibrator, an output signal of the phase shifter, and the strain detection signal or drive signal that does not go through the phase shifter. a mixing section that adds the signals; an amplifying section that amplifies the signal of the mixing section;
An atomizer driving device comprising: a driving section that transmits a signal from the amplifying section to the electric vibrator. 2. The atomizer drive device according to claim 1, wherein the phase shift degree of the phase shift section is π/2.