JPS6125436B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circular ultrasonic transducer developed especially for large-sized cleaners.

This type of circular vibrator used in cleaning equipment is the first
As shown in the figure, a piezoelectric transducer 2 that exhibits longitudinal vibration at a half wavelength is integrally coupled to the center of a circular diaphragm 1, but the diameter of the diaphragm is Since it cannot be made much larger than the acoustic radiation surface of the piezoelectric transducer connected to it, the ultrasonic irradiation area is small, and it is mainly applied to small-sized cleaners.

On the other hand, if the diameter of the diaphragm is increased as shown by the chain line in order to widen the ultrasonic irradiation area, transverse vibration (indicated by the dotted line A) will be induced in addition to the longitudinal vibration, resulting in a large vibration loss and insufficient cleaning. It was not effective and therefore it was considered impossible to apply it to large cleaning machines.

In the present invention, the diameter of the diaphragm is made large enough to fit a large-sized washing machine, one piezoelectric transducer is coupled to the center of one side of the diaphragm, and the piezoelectric transducer at the center is connected to the diaphragm. By coupling a large number of piezoelectric transducers concentrically arranged around the diaphragm at intervals of 1/4 wavelength or less of the lateral vibration generated in the diaphragm during excitation, To develop a circular ultrasonic vibrator particularly suitable for large-sized cleaners, which suppresses vibration and generates only a single longitudinal vibration to radiate uniform ultrasonic waves without loss from a wide irradiation surface of a diaphragm. This was particularly successful, and the drawings from FIG. 2 onwards will be explained.

FIG. 2 shows the basic aspect of the present invention, 1
1 is a diaphragm made of stainless steel or the like in a circular shape with a desired diameter.Generally, in adhesive type cleaners, a cylindrical cleaning tank is used instead, and in immersion type cleaners, it is immersed in the cleaning liquid. The upper plate of the cylindrical sealed case is used as a diaphragm. 12... are a plurality of piezoelectric transducers exhibiting longitudinal vibration at a half wavelength, for example, as shown in FIG. 4, a pair of piezoelectric elements 21,
A so-called Languevin type vibrator is generally used, in which a transducer 22 is sandwiched between a pair of metal blocks 23 and 24 and these are fastened together with bolts 25 or the like. These piezoelectric transducers 12... are connected to one side 1 of the diaphragm.
1', the central piezoelectric transducer 12a and the intermediate piezoelectric transducer group 12b are arranged at a central point and at positions on a plurality of concentric circles centered on the central point, and are integrally connected by means such as bolts or adhesives. . . . and the interval between the intermediate piezoelectric transducer group 12b . . . and the outer peripheral piezoelectric transducer group 12c . or 1/4 wavelength or less. Figure 2 above shows an embodiment in which the piezoelectric transducers of the intermediate and outer piezoelectric transducer groups 12b and 12c are provided close to each other. However, as shown in FIG. 3, when annular acoustic radiation plates 13a and 13b are interposed between the intermediate and outer peripheral piezoelectric transducer groups 12b and 12c and the diaphragm 11, This is economically advantageous because the distance between adjacent piezoelectric transducers can be increased and the number of transducers used can be reduced compared to the one shown in FIG. In this case, the thickness of the acoustic radiation plates 13a, 13b is adjusted to the piezoelectric transducer group 12b..., 12
It goes without saying that the total length including the length of c... is set to be equal to the half wavelength length.

According to the present invention having the above configuration, when a plurality of piezoelectric transducers 12 connected to the diaphragm 11 in a predetermined pattern are simultaneously driven at the same frequency and the same phase, the central piezoelectric transducers 12a and Parts 11a, 1 of the diaphragm that join the intermediate piezoelectric transducer 12b... and the outer piezoelectric transducer group 12c...
1b and 11c produce amplitude displacements as shown by small curves B, C, and D, respectively, and the whole exhibits longitudinal vibration with an amplitude displacement as shown by curve E. Note that the center piezoelectric transducer 12
a and the intermediate piezoelectric transducer group 12b... and the transducer group 12b... and the outer circumferential piezoelectric transducer group 1
It is desirable to set the distance between 2c to 1/4 wavelength of the transverse vibration that occurs in the diaphragm during excitation or less.If it is longer than 1/4 wavelength, the distance between This is because unnecessary lateral vibrations are added and the intended purpose cannot be achieved.

In addition, in the present invention described above, since a large number of piezoelectric transducers with the same impedance are used, the diaphragm exhibits longitudinal vibration with a displacement that increases in amplitude toward the center, as shown by curve E; Either the piezoelectric transducer group 12c has the lowest impedance and the center piezoelectric transducer 12a has the highest impedance, or the center piezoelectric transducer 12a is replaced by the middle and outer piezoelectric transducers 12b. ...,12c...
By connecting the diaphragm with a polarity opposite to that of the diaphragm, the diaphragm can be vertically vibrated with a uniform amplitude over the entire surface.

The present invention has hitherto shown embodiments in which the diaphragm is coupled to the center on one side of the diaphragm, or in which two sets of piezoelectric transducers each forming a concentric circle are coupled around one piezoelectric transducer, but the diaphragm Needless to say, one to three or more concentric piezoelectric transducer groups can be combined depending on the size of the piezoelectric transducer.

By having the above-mentioned configuration, the disk-type ultrasonic vibrator of the present invention can freely increase the diameter of the diaphragm, making it possible to apply it to large-sized cleaners, which was previously considered impossible. It has the great effect of reducing waste and exhibiting high efficiency.

[Brief explanation of the drawing]

FIG. 1 shows a conventional circular ultrasonic transducer, in which A is a plan view and B is a sectional view taken along line a-a in FIG. Fig. 2 shows a circular ultrasonic transducer according to an embodiment of the present invention, A is a plan view, B is a sectional view taken along line bb in Fig. A, and Fig. 3 shows another embodiment of the present invention. show,
A is a plan view, B is a cross-sectional view taken along line c-c in figure A,
FIG. 4 shows an embodiment of a typical Languevin type vibrator used as a piezoelectric transducer. 11...Circular diaphragm, 12...Plural piezoelectric transducers, 13a, 13b...Annular acoustic radiation plate.

Claims (1)

[Claims] 1. On one side of a circular diaphragm with a relatively large diameter, one piezoelectric transducer is coupled to the center of the diaphragm, and 1/1 of the transverse vibration that occurs in the diaphragm during excitation is applied around the piezoelectric transducer. A circular ultrasonic transducer consisting of a group of piezoelectric transducers arranged concentrically at intervals of four wavelengths or less. 2 A piezoelectric transducer is connected to the center of one side of a circular diaphragm with a relatively large diameter, and a piezoelectric transducer is connected around it to the center of the circular diaphragm, and a transverse vibration of 1/4 wavelength or less is generated in the diaphragm during excitation. A group of piezoelectric transducers arranged concentrically with a length interval is coupled, and an annular acoustic radiating plate is interposed between the joint surface of the diaphragm and the group of piezoelectric transducers arranged concentrically. A circular ultrasonic transducer. 3 A piezoelectric transducer is connected to the center of one side of a circular diaphragm with a relatively large diameter, and a piezoelectric transducer is connected around it at the 1/4 wavelength or less of the transverse vibration that occurs in the diaphragm during excitation. A group of piezoelectric transducers arranged concentrically with a length interval is coupled, and the piezoelectric transducer coupled to the center of the diaphragm and the group of piezoelectric transducers arranged concentrically are made to have different impedances. , a circular ultrasonic vibrator with the center piezoelectric transducer side being the highest. 4 A piezoelectric transducer is connected to the center of one side of a circular diaphragm with a relatively large diameter, and a piezoelectric transducer is connected around it to the center of the circular diaphragm, and a piezoelectric transducer is placed around it at a wavelength of 1/4 wavelength or less of the transverse vibration that occurs in the diaphragm during excitation. A group of piezoelectric transducers arranged concentrically with a length interval is coupled, and the piezoelectric transducer coupled to the center of the diaphragm has opposite polarity to the group of piezoelectric transducers arranged concentrically. A circular ultrasonic transducer connected to the