WO2007026872A1

WO2007026872A1 - Ultrasonic vibration unit and ultrasonic atomizer

Info

Publication number: WO2007026872A1
Application number: PCT/JP2006/317328
Authority: WO
Inventors: Seichin Kinuta; Daisuke Takahata
Original assignee: Optnics Precision Co., Ltd.; Fukoku Co., Ltd.
Priority date: 2005-09-02
Filing date: 2006-09-01
Publication date: 2007-03-08
Also published as: JP4906728B2; JPWO2007026872A1

Abstract

[PROBLEMS] An ultrasonic vibration unit having a piezoelectric ceramics and used in an atomizer, wherein the vibration efficiency of a plate to be vibrated fixed to the piezoelectric ceramics is enhanced. [MEANS OF SOLVING PROBLEMS] The ultrasonic vibration unit (21) comprises a ring-plate-form piezoelectric ceramics (23) and an oblong plate to be vibrated (27) fixed to it. The piezoelectric ceramics (23) has first and second electrodes (29a, 29b) on opposing first and second surfaces (d3, d4). The plate to be vibrated (27) has many fine pores (33), is disposed so as to cross the hollow portion (25) of the piezoelectric ceramics (23) and is fixed with its opposite ends overlaid on the piezoelectric ceramics (23).

Description

Specification

Ultrasonic vibration unit and ultrasonic atomizer

Technical field

The present invention relates to an ultrasonic vibration unit and an ultrasonic atomizer, and more particularly to an ultrasonic vibration unit suitable for atomizing a liquid such as water or a chemical solution and an ultrasonic atomizer using the ultrasonic vibration unit.

Background art

Conventionally, for example, a configuration shown in FIG. 10 is known as an atomizing device for atomizing a liquid such as water or a chemical solution.

[0003] That is, for example, water 3 is stored in the lower part inside the liquid storage unit 1 that also serves as the main body case of the apparatus, and the ultrasonic vibration unit 7 is supported by the support member 5 provided inside the upper part of the liquid storage unit 1. A conical column-shaped supply section 9 that consists of a dice or the like and supplies water 3 in the liquid storage section 1 upwardly extends from the inner bottom of the liquid storage section 1 to the ultrasonic vibration unit 7. Japanese Patent No. 2698488 (Patent Document 1) is in this field.

For example, as shown in FIGS. 11A and 11B, the ultrasonic vibration unit 7 includes a ring-plate-shaped piezoelectric ceramic 13 in which electrodes l la and l ib are formed on the first and second surfaces dl and d2 facing each other. The outer surface of the disc-shaped vibrating plate 15 is overlapped with the second surface (bottom surface) d2 of the piezoelectric ceramic 13 to close the through-hole, and the vibrating plate 15 has a number of small holes 17 in the thickness direction. And a structure in which the outer peripheral portion of the piezoelectric ceramic 13 is sandwiched between support members 5 made of an insulating elastic body.

[0005] Note that the small holes 17 of the vibration plate 15 are fine, and are not shown in FIG. 11A, but are exaggerated in FIG.

[0006] Then, the ultrasonic atomizer shown in FIG. 10 applies a predetermined AC drive voltage to the electrodes l la and l ib of the ultrasonic vibration unit 7 and spreads (lengths) vibrations to the piezoelectric ceramic 13. The vibration plate 15 is ultrasonically vibrated based on this vibration, and the water 3 supplied from the lower part of the liquid storage unit 1 to the vibration plate 15 by the supply unit 9 is atomized from a large number of small holes 17 to the outside. To send to. Reference numeral 19 in FIG. 10 is a stopper plugging the water 3 entrance. Patent Document 1: Japanese Patent No. 2698488

Disclosure of the invention

Problems to be solved by the invention

However, in the ultrasonic vibration unit 7 described above, the outer peripheral portion of the disk-shaped vibrating plate 15 is overlaid on the second surface d2 so as to close the through hole of the ring-shaped piezoelectric ceramic 13. The entire circumference of the outer periphery of the disc-shaped vibrating plate 15 is fixed to the second surface d 2 of the piezoelectric ceramic 13. For this reason, stress is applied from the entire circumference to the center of the vibration plate 15 which is ultrasonically vibrated by expansion vibration (radial expansion and contraction) of the piezoelectric ceramic 13, so that the vibration plate 15 is sufficiently There is a difficulty that vibration deformation (deflection deformation) is difficult.

Therefore, even if an ultrasonic atomizer is configured using the ultrasonic vibration unit 7 described above, the atomization efficiency is difficult to improve for the amount of electric energy applied to the piezoelectric ceramic 13. Improvement was desired.

[0009] The present invention has been made to solve such a problem, and an ultrasonic vibration unit capable of improving the vibration efficiency of a vibration plate fixed to piezoelectric ceramics and a superfine atomization efficiency. An object is to provide a sonic atomizer.

Means for solving the problem

[0010] In order to solve such a problem, the ultrasonic vibration unit according to the present invention has first and second electrodes on the first and second surfaces facing each other in the thickness direction, and spread vibration. And a vibrating plate having a large number of small holes and fixed at opposite ends of the piezoelectric ceramic. The vibrating plate is mounted on the basis of the vibration of the piezoelectric ceramic. It is to vibrate ultrasonically.

Here, in the present invention, a frame-type piezoelectric ceramic means a piezoelectric ceramic having a through hole in its thickness direction (polarization direction) and having an overall shape of a rectangular shape or a ring shape. Also, the width and thickness dimensions of the frame portion are arbitrary. In addition, a piezoelectric ceramic having a shape having a notch in a part of the frame portion is also included in the frame-type piezoelectric ceramic.

[0012] In the ultrasonic vibration unit according to the present invention, a gap may be formed between a width direction end portion orthogonal to the both end direction of the vibration plate and the piezoelectric ceramic. [0013] Further, the ultrasonic vibration unit according to the present invention may have a configuration in which a plurality of the plates to be vibrated are arranged side by side on the piezoelectric ceramics at intervals.

[0014] Furthermore, in the ultrasonic vibration unit according to the present invention, a single notch is formed in the piezoelectric ceramic on one end side of the plurality of vibrating plates, and the notch is avoided. It is also possible to arrange these vibrating plates.

[0015] Further, in the ultrasonic vibration unit according to the present invention, it is possible to provide a protrusion on the vibration plate.

[0016] In the ultrasonic vibration unit according to the present invention, it is also possible to adopt a configuration in which the slope of the protrusion is a drainage gradient of the liquid adhering to the vibration plate.

And the ultrasonic atomizer which concerns on this invention is comprised using one of the ultrasonic vibration units mentioned above.

The invention's effect

[0017] The ultrasonic vibration unit of the present invention having such means has first and second electrodes facing each other in the thickness direction, and has a large number of small holes at the opposing portion of the piezoelectric ceramic. Both ends of the driven plate are fixed to a frame-type piezoelectric ceramic. Therefore, no stress is applied from the entire circumference to the central portion of the vibration plate 15 that is ultrasonically vibrated by the expansion vibration (radial expansion and contraction) of the piezoelectric ceramic 13. Therefore, based on the vibration of the piezoelectric ceramic, Since the vibration plate is easily deformed by vibration (flexure deformation), the vibration efficiency of the vibration plate can be improved.

[0018] In the configuration in which a gap is formed between the width direction end portion orthogonal to the both end portions direction of the vibration plate and the piezoelectric ceramic, the width direction end portion of the vibration plate is the piezoelectric ceramic and the machine. Therefore, it is possible to further improve the efficiency of ultrasonic vibration of the vibration plate.

[0019] Further, in the configuration in which a plurality of the vibration plates are arranged side by side on the piezoelectric ceramic, when an ultrasonic atomizer is configured using the piezoelectric ceramics, different liquids can be atomized. .

[0020] Furthermore, in the configuration in which one notch is formed in the piezoelectric ceramic on one end side of the plurality of the vibration plates, and the vibration plate is disposed avoiding the notches, There is an advantage that there is no restriction of polarity in the electrical drive of the piezoelectric ceramic.

[0021] Further, in the configuration in which the vibration plate is provided with a protrusion, a portion having a different rigidity is formed on the vibration plate, and thus when the ultrasonic atomizer is configured using the vibration plate, the atomization efficiency is improved. There is an advantage to improve.

In addition, in the configuration in which the inclined surface of the protrusion is the drainage gradient of the liquid adhering to the vibration plate, the liquid atom adhering to the vibration plate is formed when the ultrasonic atomizer is configured using the slope. Is easy to flow into the air gap, which has the advantage of further improving the atomization efficiency.

[0023] Then, in the ultrasonic atomization apparatus configured using any of the ultrasonic vibration units described above, high atomization efficiency can be obtained.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 are a plan view and a cross-sectional view showing an ultrasonic vibration unit according to the present invention.

In FIG. 1 and FIG. 2, the ultrasonic vibration unit 21 is a ring plate-shaped piezoelectric ceramic 2

3 and a rectangular vibration plate 27 that is stacked across the through hole 25 of the piezoelectric ceramic 23 and overlapped therewith.

Although the ultrasonic vibration unit 21 is supported by the apparatus by the support member 5 as shown in FIG. 10 described above, the support member is not shown because it is not a main part of the present invention.

[0028] The piezoelectric ceramic 23 is formed into a thin plate shape from a conventionally known ultrasonic piezoelectric material, for example, lead zirconate titanate or a material in which this lead is replaced by molybdenum, and is provided with polarization in the thickness direction. .

As shown in FIG. 2, the piezoelectric ceramic 23 has a first surface 29a made of a conductive material such as gold on the first surface (upper surface in the drawing) d3 facing in the thickness direction. On the surface (lower surface in the figure) d4, a similar second electrode 29b is formed in a ring band shape slightly smaller than the outer shape of the piezoelectric ceramic 23, and lead wires (not shown) are connected to each other.

[0030] The vibration plate 27 is made of a thin conductive material plate such as a nickel material, for example, and its both end portions are overlapped with the opposite portion of the second surface d4 of the piezoelectric ceramic 23, and a conventionally known method such as an adhesive is used. It is fixed.

[0031] Therefore, in the vibration plate 27, the width direction orthogonal to the direction between both ends (arrow T in FIG. 1). Gaps 31 are formed between both sides in the direction (the arrow W direction in FIG. 1) and the inner surface of the through hole 25 of the piezoelectric ceramic 23.

[0032] The vibrating plate 27 is formed with a plurality of (numerous) fine holes 33 penetrating in the thickness direction. These small holes 33 are tapered such that the diameter on the contact surface (upper surface) side with the piezoelectric ceramic 23 is smaller than the diameter on the opposing surface (lower surface) side. In FIG. 1, the illustration of the small hole 33 is omitted, and in FIG. 2, it is exaggerated.

[0033] When such an ultrasonic vibration unit 21 applies an AC drive voltage of 20 Vp-p at 133 KHz, for example, between the first and second electrodes 29a and 29b via the lead wires, the piezoelectric ceramic 23 becomes long. It spreads and vibrates in the direction (radial direction). Then, the vibrating plate 27 supported by the opposing portion of the piezoelectric ceramic 23 is deformed (flexed) by vibration of the piezoelectric ceramic 23. That is, the vibration plate 27 is ultrasonically vibrated by the vibration of the piezoelectric ceramic 23.

Therefore, as shown in FIG. 2, a liquid supply unit 35 such as a sponge is applied to the lower surface of the vibration plate 27, and from the lower part of the liquid storage unit as in the ultrasonic atomizer shown in FIG. When water is supplied by the supply unit 35, the water 3 is atomized and sent out through a large number of small holes 33.

[0035] Thus, the ultrasonic vibration unit 21 of the present invention has the first and second electrodes 29a on the first and second surfaces d3 and d4, which are opposite surfaces in the thickness direction of the piezoelectric ceramic 23, A rectangular vibrating plate 27 having a large number of small holes 33 formed by forming 29b is arranged so as to cross the hollow portion 25 of the piezoelectric ceramic 23, and both end portions thereof are overlapped and fixed. .

[0036] Therefore, in the ultrasonic vibration unit 21, when the piezoelectric ceramic 23 vibrates due to expansion, the vibration plate 27 whose both ends are fixed to the opposing portion of the piezoelectric ceramic 23 is mainly long in the longitudinal direction. Stress is applied in the direction T, that is, mainly in a single direction. Therefore, the vibration plate 27 is easily subjected to vibration deformation (bending deformation) due to the vibration of the piezoelectric ceramic 23, and large ultrasonic vibration is easily generated. The vibration efficiency of the vibration plate 27 can be improved.

[0037] Therefore, when an ultrasonic atomizer is configured using such an ultrasonic vibration unit 21, good atomization efficiency can be obtained.

FIG. 3 shows the amount of atomization when the width W of the vibration plate 27 is changed without changing the shape of the piezoelectric ceramic 23 and the length direction の of the vibration plate 27. [0039] In the vibrating plate 27, if the width W1 is narrowed from the wide width W1 that closes the through hole 25 of the piezoelectric ceramic 23, the amount of atomization increases as the vibrating plate 27 becomes easier to vibrate. Maximum at W2. When the width is narrowed to some extent, it can be seen that the area of the diaphragm 27 itself is narrowed, the number of small holes 33 is reduced, and the amount of atomization is reduced.

[0040] The vibration plate 27 in the present invention is not limited to a rectangular shape as shown in FIG.

[0041] That is, the vibration plate 27 is oblong as shown in Fig. 4A, rectangular as shown in Fig. B, with four corners cut diagonally in a straight line, and cut out into four curves as shown in Fig. C. Rectified rectangle, rectangle with four corners cut out in an L shape as shown in Fig. D, rough rectangle with the center in the longitudinal direction bulged as shown in Fig. E, both ends as shown in Fig. F It can be implemented in various shapes such as a substantially rectangular shape that is narrowed by cutting into a concave shape near the portion, and a somewhat elongated shape formed in the direction of both ends overlapping the piezoelectric ceramic 23 is preferable. In addition, it is preferable that the vibrating plate 27 has a large area at the central portion with which the supply unit 35 contacts in terms of atomization efficiency.

[0042] Furthermore, as shown in FIGS. 5A and 5B, the vibration plate 27 according to the present invention has a protrusion 37 at the center in the longitudinal direction. By providing a portion with different rigidity on the vibration plate 27, there is an advantage of improving the atomization efficiency. Further, since the slope of the protrusion 37 functions as a drainage gradient of the liquid adhering to the vibration plate 27, it is easier to improve the atomization efficiency than the liquid adhering to the vibration plate 27 easily flows down.

In the above-described embodiment, a force exemplifying the case where gaps 31 are formed between the both sides of the vibration plate 27 and the inner surface of the through hole 25 of the piezoelectric ceramic 23, respectively. By forming one side of the plate 27 into a semicircular shape, it is possible to close one of the gaps 31. In addition, each of the vibration plates 27 can be formed in a disk shape, so that each of the gaps 31 can be closed. However, in any case, only the both ends of the vibration plate 27 are fixed to the facing portion of the piezoelectric ceramic 23.

Next, another embodiment of the ultrasonic vibration unit according to the present invention will be described with reference to FIGS.

[0044] The configuration shown in Fig. 6 includes a first or second electrode 41a, 41b (second electrode 41b) on the opposing surfaces of a pair of opposing sides 39a, 39b of a rectangular or quadrangular frame-type piezoelectric ceramic 39. Can't see . The first and second electrodes 41a, 41b are not formed, and the other ends of the pair of opposing sides 39c, 39d are overlapped and fixed to the center of the above-mentioned rectangular vibration plate 27. This is an ultrasonic vibration unit 43.

In the ultrasonic vibration unit 43 having such a configuration, when the same AC drive voltage is applied between the first and second electrodes 41a and 41b, the distance between the opposing sides 39c and 39d of the frame-type piezoelectric ceramic 39 increases. In other words, the vibrating plate 27 vibrates so as to narrow, and stress is applied to the vibrating plate 27 in a single longitudinal direction. Therefore, the vibration plate 27 is easily subjected to vibration deformation (flexure deformation), and the above-described effect can be obtained in which large ultrasonic vibration is easily generated.

Further, the configuration shown in FIG. 7 is the same as that of the frame-type piezoelectric ceramic 39 shown in FIG. 6, except that the first and second electrodes 41a and 41b (not shown) are not formed on the pair of opposing sides 39c and 39d. This is an ultrasonic vibration unit 45 in which three vibration plates 27 are arranged in parallel and fixed at intervals. The first and second electrodes 41a and 41b are not shown (the same applies to FIG. 9).

[0047] In such an ultrasonic vibration unit 45, it is possible to vibrate the three vibrating plates 27 independently. Therefore, not only can the amount of atomization be improved, but also, as shown in FIG. 8, a supply portion 35 can be arranged and brought into contact with each vibration plate 27 to supply different liquids.

[0048] When it is not preferable to mix a plurality of liquids in advance, in such an ultrasonic vibration unit 45, different liquids can be independently supplied from the individual supply units 35 to the vibration plate 27 and atomized. Thus, it is possible to avoid the problem of mixing in advance.

[0049] It is also possible to simultaneously atomize liquids containing pigments and the like of different colors to generate mist of new colors, and to drive intermittently by shifting the driving time of each vibration plate 27 Thus, it is possible to continuously generate fog having different colors at a predetermined cycle.

Furthermore, as shown in FIG. 9, in the configuration in which a plurality of vibration plates 27 are arranged in parallel at intervals on the frame-type piezoelectric ceramic 39, a notch 47 is formed on one of the opposing sides 39c and 39d. However, it is possible to construct the ultrasonic vibration unit 49 by avoiding the notch 47 and arranging the vibration plates 27 in two groups.

[0051] In the ultrasonic vibration unit 49 having such a notch 47, when an AC drive voltage of +/- is applied to the first and second electrodes 41a and 41b on the opposing side 39a, 1st, 2nd It is possible to apply a reverse AC drive voltage of _Z + with the electrodes 41a and 41b, and there is an advantage that the polarity of the applied voltage is not limited.

[0052] Thus, in the ultrasonic vibration units 21, 43, 45, 49 of the present invention, the frame-shaped piezoelectric ceramic includes a ring plate shape, and in addition to the closed frame shape, a cutout portion 47 is provided. Includes C-shapes.

[0053] Further, the ultrasonic vibration units 21, 43, 45, and 49 according to the present invention can be used as vibration sources for various devices and applications, such as when powder is scattered.

By the way, the ultrasonic atomization apparatus of the present invention using the above-described ultrasonic vibration units 21, 43, 45, and 49 includes a supply unit 35 that supplies a stored liquid in a desired direction, and a thickness direction. The first and second surfaces d3 and d4 that face each other at the first and second electrodes 29a, 29b, 41a, and 41b, respectively, and the frame-type piezoelectric ceramics 23 and 39 that spread and vibrate, and a number of small holes And a vibrating plate 27 having piezoelectric ceramics 23 and 39, both ends of which are fixed to opposite portions. The liquid force supplied by the supply unit 35 has a configuration that is atomized by the ultrasonic vibration of the vibration plate 27 based on the vibration of the piezoelectric ceramics 23 and 39. Industrial applicability

[0055] The present invention is suitable for atomizing a liquid such as water or a chemical solution.

Brief Description of Drawings

FIG. 1 is a plan view showing an embodiment of an ultrasonic vibration unit according to the present invention.

2 is a cross-sectional view of the ultrasonic vibration unit shown in FIG.

FIG. 3 is a diagram showing the atomization characteristics when the ultrasonic vibration unit shown in FIG. 1 is used in an ultrasonic atomizer.

4 is a view showing still another example of a vibration plate used in the ultrasonic vibration unit of FIG.

FIG. 5 is a perspective view A and a sectional view B (a cross section between bb in FIG. 5A) showing another example of a vibration plate used in the ultrasonic vibration unit of FIG.

FIG. 6 is a plan view showing another embodiment of the ultrasonic atomizer according to the present invention.

FIG. 7 is a plan view showing another embodiment of the ultrasonic atomizer according to the present invention.

8 is a cross-sectional view showing an example of use of the ultrasonic vibration unit shown in FIG. FIG. 9 is a plan view showing still another embodiment of the ultrasonic atomizer according to the present invention.

FIG. 10 is a schematic cross-sectional view showing an atomizing apparatus that serves as a reference for the present invention.

FIG. 11 is a plan view A and a sectional view B showing a conventional ultrasonic vibration unit.

Explanation of symbols

1 Liquid reservoir (device main unit)

3 Water (liquid)

5 Support member

7, 21, 43, 45, 49 Ultrasonic vibration unit

9, 35 Supply section

l la, l ib electrode

13, 23, 39 Piezoelectric ceramics

15, 27 Vibrated plate

17, 33 / J

19 Stopper

25 Through hole

29a, 41 a 1st electrode

29b, 41b Second electrode

31 Air gap

37 Projections

39a, 39b, 39c, 39d Opposite sides

47 Notch

dl, d3 first surface

d2, d4 second side

Claims

The scope of the claims

[1] A frame-type piezoelectric ceramic having first and second electrodes on the first and second surfaces facing each other in the thickness direction, and expanding and vibrating,

A vibrating plate having a large number of small holes and having both end portions fixed to opposing portions of the piezoelectric ceramic;

Comprising

An ultrasonic vibration unit, wherein the vibration plate is ultrasonically vibrated based on the vibration of the piezoelectric ceramic.

2. The ultrasonic vibration unit according to claim 1, wherein a gap is formed between the piezoelectric ceramics and a width direction end perpendicular to the direction of both ends of the vibration plate.

[3] The ultrasonic vibration unit according to [1] or [2], wherein the plurality of vibration plates are arranged in parallel with the piezoelectric ceramics at intervals.

[4] The piezoelectric ceramic has one notch portion on one end side of the plurality of the vibration plates, and the vibration plate is arranged avoiding the notches. The ultrasonic vibration unit according to claim 3.

[5] The ultrasonic vibration unit according to any one of [1] to [4], wherein the vibration plate has a protrusion.

6. The ultrasonic vibration unit according to claim 2, wherein the vibration plate has a protrusion, and becomes a drainage gradient of the liquid to which the inclined surface of the protrusion adheres.

[7] An ultrasonic atomizer using the ultrasonic vibration unit according to any one of claims 1 to 6.