Ultrasonic radiation unit

Abstract

The present application provides an ultrasonic radiation unit (21) having a vibrating plate (12), BLT-type ultrasonic transducers (31), and resonance rods (51, 59) resonating at the same frequency as the ultrasonic transducers (31) and in a longitudinal vibration mode. The plurality of ultrasonic transducers (31) is formed using four or more lead-free piezoelectric ceramic piezoelectric elements (42) and is arranged at each vertex (p2) of a virtual regular hexagon (H1) in the central portion of the vibrating plate (12). A first resonance rod (51) having a large cross-sectional area is arranged at the center (p1) of the regular hexagon (H1) and at a position adjacent to the regular hexagon (H1) from the outside on the short side (12b) side of the vibrating plate (12). A second resonance rod (59) having a small cross-sectional area is arranged at a position adjacent to the regular hexagon (H1) from the outside on the long side (12a) side of the vibrating plate (12). According to the present application, an ultrasonic radiation unit having excellent corrosion resistance and thus a long service life and excellent uniformity of vibration displacement distribution and thus less cleaning unevenness can be provided at low cost.

Description

Technical Field

[0001] The present invention relates to an ultrasonic emission unit that emits ultrasonic waves from an ultrasonic transducer. Background Technology

[0002] Previously, ultrasonic cleaning devices equipped with ultrasonic emission units, which clean objects by irradiating them with ultrasonic waves (ultrasonic cleaning), have been put into practical use. Ultrasonic cleaning combines the physical action of ultrasonic waves with the chemical action of the cleaning fluid, enabling it to reach even the smallest, most complex parts of objects, achieving highly efficient cleaning. Therefore, it has become an indispensable piece of equipment in the manufacturing of precision mechanical components, optical components, liquid crystal displays, semiconductors, and other related products.

[0003] Figure 8 The existing ultrasonic cleaning apparatus 200 shown includes a vibrating plate 201, also known as a radiating plate. The vibrating plate 201, which in most cases also serves as the bottom of the cleaning tank 202, is formed of a stainless steel plate several millimeters thick. Multiple bolts fasten a Rangevin-type ultrasonic transducer 204 to the non-radiating surface 203 of the vibrating plate 201, which constitutes the ultrasonic radiating unit. The side of the vibrating plate 201 opposite to the non-radiating surface 203 is the ultrasonic radiating surface 205. For example, when using an ultrasonic radiating unit that generates ultrasonic waves of tens of kilohertz, an ultrasonic cleaning apparatus 200 can be constructed that cleans the object 207 being cleaned by strong shock waves generated by cavitation phenomena induced by ultrasonic waves in the cleaning fluid 206.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-058883 ( Figure 1 wait).

[0005] However, as the cleaning area of ​​the ultrasonic cleaning device 200 expands, the radiating surface of the vibrating plate 201 also increases. Therefore, when constructing an ultrasonic radiating unit, it is originally desirable to set multiple ultrasonic transducers 204 on the vibrating plate 201 with a larger radiating surface. However, attempting to use multiple ultrasonic transducers 204 to construct an ultrasonic radiating unit would increase the manufacturing cost of the device. On the other hand, if the number of ultrasonic transducers 204 that matches the size of the vibrating plate 201 is not set, gaps (transducer-free areas) will be generated between adjacent transducers. As a result, there is a problem of erosion 208 of the vibrating plate 201 due to cavitation. In addition, there is a problem of uneven cleaning due to uneven vibration displacement distribution of the vibrating plate 201 (i.e., sound pressure distribution deviation).

[0006] Therefore, the inventors of this application have proposed an ultrasonic radiating unit with a structure in which resonant rods are arranged between multiple ultrasonic transducers (for example, see Patent Document 1). According to this structure, the area without transducers and resonant rods on the non-radiating surface can be reduced. However, even with such a structure, it cannot be said that sufficient reduction in erosion and uniformity of vibration displacement distribution are achieved.

[0007] The present invention was made in view of the above-mentioned problems, and its object is to provide an ultrasonic radiation unit that has excellent corrosion resistance and thus a long lifespan, excellent uniformity of vibration displacement distribution and thus less cleaning unevenness, and can be implemented at low cost. Summary of the Invention

[0008] To address the aforementioned issues, the present invention provides a first ultrasonic emitting unit having an ultrasonic emitting surface and a non-emitting surface located opposite the ultrasonic emitting surface. The non-emitting surface comprises: a rectangular vibrating plate with protruding bolts; a plurality of bolts securing a Langevin-type ultrasonic transducer, the transducer's front panel being joined to the non-emitting surface; and a plurality of resonant rods resonating at the same frequency as the ultrasonic transducers and in a longitudinal vibration mode. The plurality of ultrasonic transducers and resonant rods are fastened to the plurality of bolts. The ultrasonic transducers are characterized by being constructed using four or more lead-free piezoelectric ceramic piezoelectric elements, disposed at the vertices of at least one virtual regular hexagon in the center of the vibrating plate; the resonant rods consist of a first resonant rod with a relatively large cross-sectional area and a second resonant rod with a relatively small cross-sectional area; the first resonant rod is disposed at the center of the regular hexagon and is located on the short side of the vibrating plate, adjacent to the regular hexagon from the outside; the second resonant rod is disposed on the long side of the vibrating plate, adjacent to the regular hexagon from the outside.

[0009] Therefore, by employing the first type of ultrasonic radiating unit, since the ultrasonic transducer is composed of four or more lead-free piezoelectric ceramic piezoelectric elements, a greater driving power can be supplied to a single transducer compared to using only two. Furthermore, by arranging the ultrasonic transducers of the above structure at the vertices of at least one virtual regular hexagon in the center of the rectangular vibrating plate from top view, the vibrating plate can be vibrated efficiently even with a small number of transducers. Additionally, by arranging the first and second resonant rods with different cross-sectional areas in a prescribed manner, uniform longitudinal vibration can be obtained on a wider radiating surface of the vibrating plate. As a result, erosion of the vibrating plate is reduced, and a uniform vibration displacement distribution is easily obtained.

[0010] Furthermore, the structure of a resonant rod is simpler than that of an ultrasonic transducer, which consists of multiple components, and therefore can be manufactured at a lower cost. Thus, for example, in an ultrasonic emission unit with a vibrating plate requiring a wide cleaning area, by reducing the number of ultrasonic transducers used and using a low-cost resonant rod, a device with excellent corrosion resistance and uniform vibration displacement distribution can be achieved at a low cost.

[0011] The second type of ultrasonic emission unit provided by the present invention is based on the first type of ultrasonic emission unit, wherein there are two virtual regular hexagons sharing one side in the central part of the vibrating plate, and a plurality of ultrasonic transducers are arranged at each vertex of the two regular hexagons.

[0012] The third type of ultrasonic emission unit provided by the present invention is based on the first type of ultrasonic emission unit, wherein the number of ultrasonic transducers is less than the sum of the number of the first resonant rod and the number of the second resonant rod, and the number of the first resonant rod is greater than the number of the second resonant rod.

[0013] The fourth type of ultrasonic emission unit provided by the present invention is based on the first type of ultrasonic emission unit, wherein three or more of the first resonant rods are arranged along the short side of the vibrating plate.

[0014] The fifth type of ultrasonic emission unit provided by the present invention is based on the first type of ultrasonic emission unit, wherein the first resonant rod has a diameter equal to the maximum diameter of the front panel of the ultrasonic transducer, and the second resonant rod has a diameter of more than 1 / 2 and less than 3 / 4 of the maximum diameter of the front panel of the transducer.

[0015] The sixth ultrasonic emission unit provided by the present invention is based on the first ultrasonic emission unit, wherein the center distance between the first resonant rod and the adjacent ultrasonic transducer is equal to the center distance between two adjacent ultrasonic transducers, and the center distance between the second resonant rod and the adjacent ultrasonic transducer is shorter than the center distance between two adjacent ultrasonic transducers.

[0016] As detailed above, by using the first to sixth types of ultrasonic radiating units, it is possible to achieve ultrasonic radiating units with excellent corrosion resistance and thus long lifespan, and excellent uniformity of vibration displacement distribution and thus less uneven cleaning at low cost. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the ultrasonic cleaning apparatus according to the embodiment. Figure 2 This is a top view of the vibrating plate type ultrasonic radiation unit of the embodiment; Figure 3 yes Figure 2 AA-line sectional view; Figure 4 yes Figure 2 BB line section view; Figure 5 This is a table showing the vibration displacement analysis results of Comparative Example 1, Comparative Example 2, and the Example; Figure 6 This is a top view of a vibrating plate type ultrasonic radiation unit according to another embodiment; Figure 7 This is a top view of a vibrating plate type ultrasonic radiation unit according to another embodiment; Figure 8 This is a schematic diagram of an existing ultrasonic cleaning device. Detailed Implementation

[0018] The following is based on Figures 1 to 5 The following detailed description embodies the present invention as an ultrasonic cleaning device.

[0019] like Figure 1 As shown, the ultrasonic cleaning apparatus 10 includes a metal cleaning tank 11 for storing cleaning fluid W1 and an ultrasonic emitting unit 21. The lower end of the cleaning tank 11 has multiple bolt holes 11a. The vibrating plate 12 of the ultrasonic emitting unit 21 forms the bottom of the cleaning tank 11 and is a rectangular metal plate (in this embodiment, a stainless steel plate) with a length of 390mm × width of 240mm × thickness of 2.5mm. That is, the ultrasonic emitting unit 21 of this embodiment is a vibrating plate type ultrasonic emitting unit in which the vibrating plate 12 is disposed at the lower end of the cleaning tank 11 via a gasket 1 and is threadedly fixed by bolts 2 and nuts 3. The vibrating plate 12 has an emitting surface 13 for emitting ultrasonic waves and a non-emitting surface 14 located opposite the emitting surface 13. Positioning bolts 15 protrude from multiple locations on the non-emitting surface 14 of the vibrating plate 12 (see reference). Figure 3 , Figure 4 The outer periphery of the vibrating plate 12 is provided with a plurality of fixing holes 16 at approximately equal intervals along its entire circumference.

[0020] like Figure 1 , Figure 2 As shown, the ultrasonic emission unit 21 includes the aforementioned vibrating plate 12, multiple bolt-fastened Rangevin-type ultrasonic transducers 31, and multiple resonant rods 51 and 59. Furthermore, the ultrasonic cleaning apparatus 10 of this embodiment, using the aforementioned ultrasonic emission unit 21, irradiates the cleaning liquid W1 in the cleaning tank 11 with ultrasonic waves through each ultrasonic transducer 31, thereby cleaning the object 17 (see reference 11) contained in the cleaning tank 11. Figure 1 ) surface device.

[0021] like Figure 3 , Figure 4As shown, each ultrasonic transducer 31 is a device for irradiating ultrasonic waves, and is composed of a transducer front panel 32, a transducer back plate 33, a drive unit 41, and transducer assembly bolts 34 and nuts 38. That is, each ultrasonic transducer 31 in this embodiment is a bolt-fastened Rangevin type transducer (BLT). The transducer front panel 32 is disposed on the front end side of the ultrasonic transducer 31. The transducer front panel 32 is circular and approximately cylindrical when viewed from above. Furthermore, the circular radiating surface of the transducer front panel 32 is bonded to the non-radiating surface 14 of the vibrating plate 12 by an adhesive such as epoxy resin. In addition, the transducer front panel 32 is formed of metal materials such as aluminum, aluminum alloy, stainless steel, and titanium alloy.

[0022] The transducer backplate 33 is disposed at the rear end of the ultrasonic transducer 31. The transducer backplate 33 is circular and approximately cylindrical in plan view, and in this embodiment, it is designed to have a diameter slightly smaller than the transducer front panel 32. The drive unit 41 is formed by alternating layers of four piezoelectric elements 42 and four electrode plates 43, sandwiched between the transducer front panel 32 and the transducer backplate 33. Furthermore, the transducer backplate 33 is formed using metal materials such as aluminum, aluminum alloy, stainless steel, or titanium alloy.

[0023] Since the piezoelectric element 42 is annular and the electrode plate 43 is a roughly annular shape with a flange portion, the drive unit 41 has a bolt insertion hole 44 that passes through its center. Each piezoelectric element 42 is polarized in the thickness direction.

[0024] The piezoelectric element 42 in this embodiment is formed using a lead-free piezoelectric ceramic material. Lead-free piezoelectric ceramics are not particularly limited, but preferred examples include, for instance, potassium aluminate niobate-based piezoelectric ceramic materials and BNT-BT-based piezoelectric ceramic materials whose main components are bismuth magnesium titanate and barium titanate.

[0025] like Figure 3 , Figure 4 As shown, at the center of the rear end side of the front panel 32 of the oscillator, a feature is formed along the height direction of the front panel 32 of the oscillator. Figure 3 , Figure 4 An internally threaded hole 35 extends in the vertical direction. This internally threaded hole 35 does not penetrate the front panel 32 of the oscillator. That is, the internally threaded hole 35 only opens on the rear surface of the front panel 32 of the oscillator. On the other hand, at the center of the front end side of the front panel 32 of the oscillator, a bolt insertion hole 56 for inserting a positioning bolt 15 is provided, which extends in the height direction.

[0026] The internal threaded hole 35 of the oscillator front panel 32 communicates with the bolt insertion hole 44 of the drive unit 41. On the other hand, at the center of the oscillator back plate 33, a groove is formed along the height direction of the oscillator back plate 33. Figure 3 , Figure 4A through hole 36 extends vertically. The through hole 36 opens on the front surface and communicates with the bolt insertion hole 44, and also opens on the rear surface. Furthermore, an oscillator assembly bolt 34 with external threads formed on its outer peripheral surface is inserted from the oscillator back plate 33 side, and its front end reaches the internal threaded hole 35 on the oscillator front panel 32 side via the through hole 36 and the bolt insertion hole 44. That is, the front end of the oscillator assembly bolt 34 stops at the middle of the oscillator front panel 32 and does not reach the vibrating plate 12. The oscillator assembly bolt 34 is screwed into the internal threaded hole 35. Furthermore, by screwing a nut 38 onto the protruding portion of the oscillator assembly bolt 34 that passes through the oscillator back plate 33, the oscillator front panel 32, the drive unit 41, and the oscillator back plate 33 are mutually fastened and integrated. Furthermore, the metal material forming the oscillator assembly bolt 34 and the nut 38 is not particularly limited; stainless steel is used here.

[0027] Multiple positioning bolts 15 protruding from the non-radiating surface 14 of the vibrating plate 12 are screwed into bolt insertion holes 56 on the front panel 32 of the transducer. Through this screwing, multiple ultrasonic transducers 31 are securely fixed to the vibrating plate 12.

[0028] Each ultrasonic transducer 31 in this embodiment (e.g.) Figure 1 (As shown) is a longitudinal vibration type bolt-fastening Rangevin type oscillator with a longitudinal first vibration mode (single resonant frequency 28kHz) where the longitudinal vibration component in the axial direction resonates at λ / 2 (λ: longitudinal vibration wavelength). Each ultrasonic oscillator 31 is an oscillator that vibrates at the same frequency as each other.

[0029] In addition, such as Figure 1 As shown, each ultrasonic transducer 31 is electrically connected to an ultrasonic oscillator 19. The ultrasonic oscillator 19 supplies high-frequency power to make each ultrasonic transducer 31 vibrate continuously. Driven by this high-frequency power, each ultrasonic transducer 31 irradiates the cleaning liquid W1 in the cleaning tank 11 with ultrasonic waves of 25kHz (the resonant frequency of the ultrasonic transducer 31 when it is engaged with the vibrating plate 12). In addition, the output of the ultrasonic waves (driving power) in this embodiment is set to 600W, but it is not particularly limited to this and can be set arbitrarily.

[0030] like Figures 1 to 4 As shown, the plurality of resonant rods in this embodiment are composed of a first resonant rod 51 with a relatively large cross-sectional area and a second resonant rod 59 with a relatively small cross-sectional area.

[0031] The first resonant rod 51 is a resonator that resonates at the same frequency (single resonant frequency 28kHz) as the ultrasonic transducer 31 and in a longitudinal vibration mode. The first resonant rod 51 is circular and approximately cylindrical in top view. In this embodiment, the first resonant rod 51 has a diameter D1 equal to the maximum diameter D0 of the transducer front panel 32, and is formed to be slightly longer than the ultrasonic transducer 31 (see reference). Figure 4Specifically, since the maximum diameter D0 of the front panel 32 of the oscillator is 45mmφ, the diameter D1 of the first resonant rod 51 is also 45mmφ. A bolt insertion hole 56 for inserting a positioning bolt 15 is provided at the center of the front end of the first resonant rod 51, extending along the height direction. Furthermore, by screwing the positioning bolt 15 into the bolt insertion hole 56 of the first resonant rod 51, the first resonant rod 51 is securely fixed to the vibrating plate 12.

[0032] Similar to the first resonant rod 51, the second resonant rod 59 is a resonator that resonates at the same frequency (single resonant frequency 28kHz) as the ultrasonic transducer 31 and in a longitudinal vibration mode. The second resonant rod 59 is circular in top view and approximately cylindrical. In this embodiment, the second resonant rod 59 has a diameter D2 that is more than 1 / 2 and less than 3 / 4 of the maximum diameter D0 of the transducer front panel 32 (see reference). Figure 3 This is because if the diameter D2 is too large, it will be difficult not only to position the second resonant rod 59 close to the ultrasonic transducer 31, but also to ensure the proper spacing between it and the long side 12a of the vibrating plate 12. Conversely, if the diameter D2 is too small, the effect of setting the second resonant rod 59 may not be fully achieved. Specifically, the maximum diameter D0 of the transducer front panel 32 is 45 mmφ, and the diameter D2 of the second resonant rod 59 is 30 mmφ, which is 2 / 3 of its diameter. Furthermore, the second resonant rod 59 is formed to be slightly longer than the ultrasonic transducer 31. At the center of the front end side of the second resonant rod 59, a bolt insertion hole 56 for inserting a positioning bolt 15 is provided, which extends along the height direction. And, by screwing the positioning bolt 15 into the bolt insertion hole 56 of the second resonant rod 59, the second resonant rod 59 is securely fixed to the vibrating plate 12.

[0033] The first resonant rod 51 and the second resonant rod 59 are formed using metallic materials such as aluminum, aluminum alloy, stainless steel, and titanium alloy. In this embodiment, the first resonant rod 51 and the second resonant rod 59 are formed using the same metallic material (specifically stainless steel), but of course, dissimilar metallic materials can also be used.

[0034] Next, the quantity and arrangement of the ultrasonic transducers 31, the first resonant rod 51, and the second resonant rod 59 in the ultrasonic emission unit 21 will be described in detail. In this ultrasonic emission unit 21, multiple ultrasonic transducers 31 are arranged at each vertex p2 of at least one virtual regular hexagon H1 in the center of the vibrating plate 12 (refer to...). Figure 2 More specifically, in this embodiment, two virtual regular hexagons H1 sharing one side are present in the central part of the vibrating plate 12. Furthermore, a plurality of ultrasonic transducers 31 are arranged at each vertex p2 of these two regular hexagons H1. That is, as... Figure 2 As shown, since there are 10 vertices p2 within one vibrating plate 12, the ultrasonic emission unit 21 has 10 ultrasonic transducers 31.

[0035] The first resonant rod 51 is disposed at the center p1 of the regular hexagon H1, and in this embodiment, there are two such first resonant rods 51. Furthermore, the first resonant rod 51 is also disposed on the short side 12b of the vibrating plate 12, adjacent to the regular hexagon H1 from the outside. Specifically, three or more first resonant rods 51 are disposed along the short side 12b of the vibrating plate 12. In this embodiment, there are six such first resonant rods 51. Therefore, the ultrasonic emission unit 21 has a total of eight first resonant rods 51.

[0036] The second resonant rod 59 is disposed on the long side 12a of the vibrating plate 12 and adjacent to the regular hexagon H1 from the outside. In this embodiment, there are 6 such second resonant rods 59. That is, in this embodiment, the number of ultrasonic transducers 31 is 10, which is less than the total number of the first resonant rods 51 and the second resonant rods 59 (8 + 6 = 14); the number of first resonant rods 51 is 8, which is more than the number of second resonant rods 59 (6).

[0037] Further as Figure 2 As shown, the center-to-center distance L1 between the first resonant rod 51 and the adjacent ultrasonic transducer 31 is equal to the center-to-center distance L0 between two adjacent ultrasonic transducers 31. Furthermore, the center-to-center distance L2 between the second resonant rod 59 and the adjacent ultrasonic transducer 31 is slightly shorter than the center-to-center distance L0 between two adjacent ultrasonic transducers 31. Moreover, the aforementioned center-to-center distances L0 and L1 are set to approximately 1.1 to 1.5 times the maximum diameter D0 of the transducer front panel 32. Additionally, the aforementioned center-to-center distance L2 is set to approximately 0.8 to 0.95 times the aforementioned center-to-center distances L0 and L1.

[0038] When the ultrasonic cleaning device 10 configured in this way is operated, the ultrasonic cleaning device 10 is first driven to supply high-frequency power from the ultrasonic oscillator 19 to the multiple ultrasonic transducers 31, causing each ultrasonic transducer 31 to vibrate continuously. As a result, ultrasonic waves are irradiated into the cleaning fluid W1 from the ultrasonic transducers 31. At this time, cavitation occurs in the cleaning fluid W1 along with the irradiation of ultrasonic waves, and the object to be cleaned 17 is cleaned by the impact force of the cavitation breaking.

[0039] Next, the evaluation test of the ultrasonic radiation unit 21 and its results will be described.

[0040] In this evaluation test, the sample for measurement is prepared as follows. An identical unit to the ultrasonic emission unit 21 of this embodiment is prepared as an example. Furthermore, the ultrasonic emission unit 21 of the example is... Figure 5The right column of the table states "connected with 10 BLTs + 8 φ45 resonant rods + 6 φ30 resonant rods". Additionally, an ultrasonic emission unit omitting the 6 first resonant rods 51 of the ultrasonic emission unit 21 of this embodiment is prepared as Comparative Example 2. Furthermore, the ultrasonic emission unit 21 of Comparative Example 2... Figure 5 The table column states "connected to 10 BLTs + 2 φ45 resonant rods + 6 φ30 resonant rods". Furthermore, an ultrasonic emission unit omitting all resonant rods 51 and 59 of the ultrasonic emission unit 21 of this embodiment is prepared as Comparative Example 1. In addition, the ultrasonic emission unit 21 of Comparative Example 1... Figure 5 The left column of the table states "Connect 10 BLTs".

[0041] Next, using the well-known finite element method, the vibration displacement distribution of the vibrating plate 12 of the ultrasonic emission unit of each test sample (Example, Comparative Example 1, Comparative Example 2) under water load was analyzed. Furthermore, in this analysis, a vibrating plate 12 with a length of 390 mm × width of 240 mm × thickness of 2.5 mm was used, and ten ultrasonic transducers 31 (manufactured by Honda Electric Co., Ltd., "HEC-45282Z") with a nominal frequency of 28 kHz were mounted on its non-radiating surface 14 to form an ultrasonic emission unit. The driving power of each ultrasonic transducer 31 was set to 600 W. The results are shown below. Figure 5 .

[0042] In Comparative Example 1, which did not use either the first resonant rod 51 or the second resonant rod 59, it was confirmed that the vibration displacement at the center of the vibrating plate 12 increased in a roughly cross shape, while the vibration displacement decreased in other areas. That is, it can be seen that the deviation in the vibration displacement distribution in Comparative Example 1 was very large. In addition, the deviation in the vibration displacement distribution was particularly large near the center p1 of the regular hexagon H1, and this part was prone to erosion.

[0043] In contrast, in Comparative Example 2, where multiple second resonant rods 59 were added to Comparative Example 1 and a first resonant rod 51 was added to the center p1 of the regular hexagon H1, it was confirmed that the approximately cross-shaped region with large vibration displacement was slightly wider, indicating that the deviation in the vibration displacement distribution was smaller than in Comparative Example 1. This improvement is believed to be due to the addition of multiple second resonant rods 59, etc. However, in Comparative Example 2, it was found that the vibration displacement in the peripheral region of the vibrating plate 12 was not as large.

[0044] Furthermore, in the embodiment where multiple first resonant rods 51 are added from the outer edge adjacent to the regular hexagon H1, it was confirmed that the area with large vibration displacement further expands outwards. Specifically, for example, in Comparative Example 2, although the ultrasonic transducer 31 and the second resonant rod 59 are present in the area shown by circle R1, the vibration displacement is not that large. On the other hand, in the embodiment, the vibration displacement in the area shown by circle R1 is sufficiently increased, and it can be seen that the deviation of the vibration displacement distribution is significantly reduced compared to Comparative Example 2. This improvement is considered to be due to the addition of multiple first resonant rods 51 to the outer edge adjacent to the embodiment. That is, in the embodiment, by adding multiple first resonant rods 51, the "vibration efficiency in the diagonal direction of the vibrating plate 12 is improved," thereby achieving the expansion of the area with large vibration displacement and the homogenization of the vibration displacement distribution.

[0045] Therefore, the following effects can be obtained according to this embodiment.

[0046] (1) In the ultrasonic emission unit 21 of this embodiment, the ultrasonic transducer 31 is composed of four or more lead-free piezoelectric ceramic piezoelectric elements 42. Therefore, compared with the case of using only two piezoelectric elements 42, a larger driving power can be supplied to one transducer. In addition, the ultrasonic emission unit 21 adopts a method in which the ultrasonic transducer 31 of the above structure is arranged at each vertex p2 of two virtual regular hexagons H1 in the center of the vibrating plate 12, which is rectangular in plan view. Therefore, even if the number of ultrasonic transducers 31 is small, the vibrating plate 12 can be vibrated efficiently. Furthermore, by arranging the first resonant rod 51 and the second resonant rod 59 with different cross-sectional areas in a prescribed manner, uniform longitudinal vibration can be obtained on the wider radiating surface of the vibrating plate 12. As a result, the erosion of the vibrating plate 12 is reduced, the vibrating plate 12 is not easily worn, and thus the life of the device can be extended. In addition, a uniform vibration displacement distribution is easily obtained, which can reduce the generation of uneven cleaning. As a result, an excellent ultrasonic cleaning device 10 that can clean uniformly can be provided.

[0047] Furthermore, the first resonant rod 51 and the second resonant rod 59 of this embodiment, which are made of a single material, have a simpler structure than the ultrasonic transducer 31, which is composed of multiple components. Therefore, they can be manufactured at a lower cost. Thus, for example, in an ultrasonic emission unit 21 that has a vibrating plate 12 requiring a wide cleaning area, the number of ultrasonic transducers 31 used can be reduced, and low-cost resonant rods 51 and 59 can be used. As a result, a device with excellent corrosion resistance and uniform vibration displacement distribution can be achieved at a low cost.

[0048] (2) In the ultrasonic emission unit 21 of this embodiment, specifically, two first resonant rods 51 are arranged at the center p1 of the regular hexagon H1, and six first resonant rods 51 are arranged on the short side 12b of the vibrating plate 12 and adjacent to the regular hexagon H1 from the outside. Furthermore, along... Figure 2 Three first resonant rods 51 are arranged along the short side 12b on the right side of the middle section, and along... Figure 2 Three first resonant rods 51 are also arranged in a straight line on the short side 12b of the left side. Furthermore, six second resonant rods 59 are arranged on the long side 12a of the vibrating plate 12, adjacent to the regular hexagon H1 from the outside. Further, the number of ultrasonic transducers 31 is less than the sum of the number of first resonant rods 51 and second resonant rods 59, and the number of first resonant rods 51 is greater than the number of second resonant rods 59. By adopting the above structure, the vibration efficiency in the diagonal direction of the vibrating plate 12 can be improved in particular. Therefore, the area with large vibration displacement can be expanded, and the uniformity of the vibration displacement distribution can be improved.

[0049] Furthermore, the above implementation method can be modified as follows.

[0050] In the above embodiment, two virtual regular hexagons H1 sharing one side exist in the center of the vibrating plate 12. Multiple ultrasonic transducers 31 are arranged at each vertex p2 of these two regular hexagons H1 to form an ultrasonic emission unit 21, but the embodiment is not limited to this. For example, such as... Figure 6 As shown in another embodiment of the ultrasonic emission unit 21A, three virtual regular hexagons H1 sharing at least one side are present in the center of the vibrating plate 12, and multiple ultrasonic transducers 31 can be arranged at each vertex p2 of these three regular hexagons H1. Furthermore, in the ultrasonic emission unit 21A, a unit is constructed using 14 ultrasonic transducers 31, 9 first resonant rods 51, and 8 second resonant rods 59. Alternatively, as... Figure 7 As shown in another embodiment of the ultrasonic emission unit 21B, a virtual regular hexagon H1 exists in the center of the vibrating plate 12, and multiple ultrasonic transducers 31 can be arranged at each vertex p2 of this regular hexagon H1. Furthermore, in the ultrasonic emission unit 21B, a unit is constructed using six ultrasonic transducers 31, seven first resonant rods 51, and four second resonant rods 59.

[0051] In the above embodiment, the multiple ultrasonic transducers 31 are constructed using four lead-free piezoelectric ceramic piezoelectric elements 42, but this is not a limitation. For example, six or eight piezoelectric elements 42 can also be used to construct the multiple ultrasonic transducers 31.

[0052] In the above embodiment, the ultrasonic emission unit 21 is constructed using a first resonant rod 51 and a second resonant rod 59 that are circular and approximately cylindrical in plan view, but this is not a limitation. For example, the ultrasonic emission unit 21 can also be constructed using a first resonant rod 51 and a second resonant rod 59 that are rectangular and approximately square prism in plan view. Furthermore, in this case, the shapes of the first resonant rod 51 and the second resonant rod 59 can be the same or different.

[0053] In the above embodiment, the diameter D1 of the first resonant rod 51 is equal to the maximum diameter D0 of the front panel 32 of the oscillator, both being 45 mmφ, but it is not limited to this. For example, the diameter D1 of the first resonant rod 51 can be greater than or less than the maximum diameter D0 of the front panel 32 of the oscillator. Incidentally, as in the above embodiment, when the diameter D1 of the first resonant rod 51 is equal to the maximum diameter D0 of the front panel 32 of the oscillator, it is beneficial to achieve uniformity in the vibration displacement distribution.

[0054] In the above embodiment, a headless bolt, i.e., a positioning bolt 15, is used as a bolt protruding from the non-radiating surface 14 of the vibrating plate 12. However, bolts with heads, such as hex bolts, socket head cap screws, and wing bolts, can also be used as bolts protruding from the non-radiating surface 14.

[0055] In the above embodiments, the vibrating plate type ultrasonic emitting units 21, 21A, and 21B are installed at the bottom of the cleaning tank 11 of the ultrasonic cleaning device 10 via a gasket 1, but this is not a limitation. For example, the ultrasonic emitting units 21, 21A, and 21B can be cleaning tank type units installed on positioning bolts protruding from the non-radiating surface of the bottom plate of the cleaning tank 11. Alternatively, the ultrasonic emitting units 21, 21A, and 21B can be submersible type units used in the cleaning fluid W1 added to the cleaning tank 11.

[0056] The ultrasonic emission units 21, 21A, and 21B described above are applied to an ultrasonic cleaning apparatus 10 that uses ultrasonic waves for cleaning. However, in addition to cleaning, they can also be applied to apparatuses for extraction, emulsification, dispersion, mixing, stirring, crushing, atomization, and other processing. Specifically, for example, when the ultrasonic emission unit is applied to an ultrasonic emulsification apparatus, the emulsion can be efficiently refined to nanoparticles, which can be expected to achieve long-term stabilization and reduce surfactants. Furthermore, when the ultrasonic emission unit is applied to an ultrasonic dispersion apparatus, nanoparticles (metal nanoparticles, carbon nanotubes, ceramic nanoparticles, magnetic nanoparticles, etc.) can be efficiently dispersed. Further, the ultrasonic emission unit can also be specifically embodied as an ultrasonic treatment apparatus utilizing chemical action. In this case, cavitation can be efficiently generated over a uniform and wide range, thus increasing the generation of free radicals such as hydroxyl groups generated by the high temperature and high pressure field during bubble collapse. Therefore, the reaction efficiency of chemical substances caused by free radicals can be improved, enabling efficient decomposition and neutralization of harmful substances, sterilization, and polymer polymerization.

[0057] Explanation of reference numerals in the attached figures 12: Vibrating plate 12a: Long side of the vibrating plate 12b: Short side of the vibrating plate 13: Radial surface 14: Non-radiative surface 21, 21A, 21B: Ultrasonic Emission Units 31: Ultrasonic transducer 32: Oscillator front panel 42: Piezoelectric element 51: First Resonant Rod 59: Second resonant rod D0: Maximum diameter of the front panel of the oscillator D1: Diameter of the first resonant rod D2: Diameter of the second resonant rod H1: Regular hexagon L0: Center-to-center distance between two adjacent ultrasonic transducers L1: Center-to-center distance between the first resonant rod and the adjacent ultrasonic transducer L2: Center-to-center distance between the second resonant rod and the adjacent ultrasonic transducer p1: The center of the regular hexagon p2: Vertex of the regular hexagon

Claims

1. An ultrasonic emitting unit having a radiating surface for emitting ultrasonic waves and a non-radiating surface located opposite the radiating surface, the non-radiating surface comprising: a rectangular vibrating plate with bolts protruding therefrom; a plurality of bolts securing a Langevin-type ultrasonic transducer, the front panel of which is joined to the non-radiating surface; and a plurality of resonant rods resonating at the same frequency as the ultrasonic transducer and in a longitudinal vibration mode; wherein the plurality of ultrasonic transducers and the plurality of resonant rods are fastened and fixed relative to the plurality of bolts, characterized in that... The multiple ultrasonic transducers are composed of four or more lead-free piezoelectric ceramic piezoelectric elements, and are arranged at each vertex of at least one virtual regular hexagon in the center of the vibrating plate. The plurality of resonant rods are composed of a first resonant rod with a relatively large cross-sectional area and a second resonant rod with a relatively small cross-sectional area; The first resonant rod is disposed at the center of the regular hexagon and is disposed on the short side of the vibrating plate and adjacent to the regular hexagon from the outside; The second resonant rod is positioned on the long side of the vibrating plate and adjacent to the regular hexagon from the outside.

2. The ultrasonic emission unit as described in claim 1, characterized in that: The central part of the vibrating plate contains two virtual regular hexagons sharing one side. Multiple ultrasonic transducers are arranged at each vertex of the two regular hexagons.

3. The ultrasonic emission unit as described in claim 1, characterized in that: The number of ultrasonic transducers is less than the sum of the numbers of the first resonant rod and the second resonant rod. The number of the first resonant rods is greater than the number of the second resonant rods.

4. The ultrasonic radiation unit as described in claim 1, characterized in that: Three or more of the first resonant rods are arranged along the short side of the vibrating plate.

5. The ultrasonic emission unit as described in claim 1, characterized in that: The first resonant rod has a diameter equal to the maximum diameter of the front panel of the ultrasonic transducer. The second resonant rod has a diameter that is more than 1 / 2 and less than 3 / 4 of the maximum diameter of the front panel of the oscillator.

6. The ultrasonic emission unit as described in claim 1, characterized in that: The center-to-center distance between the first resonant rod and the adjacent ultrasonic transducer is equal to the center-to-center distance between two adjacent ultrasonic transducers. The center-to-center distance between the second resonant rod and the adjacent ultrasonic transducer is shorter than the center-to-center distance between two adjacent ultrasonic transducers.

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