Acoustic wave transmitting and receiving device and method for constructing acoustic wave transmitting and receiving device

Abstract

To an acoustic wave transmitting and receiving device and a method for constructing the acoustic wave transmitting and receiving device, which are capable of lowering the frequency of the resonance mode of a front mass.SOLUTION: An acoustic wave transmitting and receiving device according to the present disclosure includes a driving element having a first end and a second end, a gap portion having a plurality of gaps distributed in a direction away from the first end, a front mass connected to the first end, and a rear mass connected to the second end.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to an acoustic wave transmitting and receiving device and a method for constructing an acoustic wave transmitting and receiving device. [Background technology]

[0002] 2. Description of the Related Art Known acoustic wave transmitting and receiving devices include an acoustic wave transmitting and receiving device that includes a front mass.

[0003] As this type of acoustic wave transmitting and receiving device, Patent Document 1 discloses a bolt-clamped Langevin type wave transmitting and receiving device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-183996 Summary of the Invention [Problem to be solved by the invention]

[0005] The electroacoustic transducer disclosed in Patent Document 1 has a configuration in which an acoustic matching layer is bonded to a front mass in order to widen the frequency band of several tens of kHz in water. However, in the electroacoustic transducer disclosed in Patent Document 1, due to constraints such as size, sound speed, and density, a resin material is mainly used for the acoustic matching layer, and bonding to a ceramic vibrator or a Langevin vibrator is required. For this reason, for example, in the electroacoustic transducer disclosed in Patent Document 1, there is a risk that the acoustic matching layer will peel off from the vibrator. Furthermore, in a resin acoustic matching layer, the stress-strain relationship easily reaches a nonlinear region during high-power wave transmission, causing problems such as distortion of the transmitted wave waveform and deterioration of the linearity of the acoustic radiation power relative to the input power. Furthermore, because the vibration mode is determined by the material of the acoustic matching layer, there is also the problem of limited design freedom.

[0006] An object of the present disclosure is to provide an acoustic wave transmitting and receiving device and a method for constructing an acoustic wave transmitting and receiving device that solves the above-mentioned problems. [Means for solving the problem]

[0007] An acoustic wave transmitting / receiving device according to one aspect of the present disclosure includes a driving element having a first end and a second end, a gap portion having a plurality of gaps distributed in a direction away from the first end, a front mass connected to the first end, and a rear mass connected to the second end.

[0008] A method for constructing an acoustic wave transmitting / receiving device according to one aspect of the present disclosure includes forming a front mass having a void portion with a plurality of voids, and connecting the front mass to a first end of a driving element having a first end and a second end and connecting a rear mass to the second end so that the plurality of voids are distributed in a direction away from the first end. [Effects of the Invention]

[0009] According to the above aspect, the resonance mode of the front mass can be easily shifted to a lower frequency. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view of an acoustic wave transmitting and receiving device according to the present disclosure. [Figure 2] FIG. 2 is a front view of FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] 1 is a side cross-sectional view of the upper half of an acoustic wave transmitting and receiving device according to the present disclosure. [Figure 5] 5 is a side cross-sectional view of the entire acoustic wave transmitting and receiving device shown in FIG. [Figure 6] 5 is a cross-sectional view schematically showing an area occupied by a gap in the acoustic wave transmitting and receiving device shown in FIG. 4. FIG. [Figure 7] FIG. 10 is a side cross-sectional view of the upper half of an acoustic wave transmitting and receiving device according to a comparative example. [Figure 8]10 is a graph showing the relationship between frequency and wave transmission voltage sensitivity in acoustic wave transmitting and receiving devices according to the present disclosure and comparative examples. [Figure 9] 1 is a side cross-sectional view of an acoustic wave transmitting and receiving device according to the present disclosure. [Figure 10] 1 is a flowchart illustrating steps in a method for constructing an acoustic wave transmitting and receiving device according to the present disclosure. [Figure 11] 1 is a flowchart illustrating steps in a method for constructing an acoustic wave transmitting and receiving device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Each embodiment will be described below with reference to the drawings. In all drawings, the same or corresponding components are designated by the same reference numerals, and common descriptions will be omitted. It should be noted that in this disclosure, the drawings may relate to one or more embodiments.

[0012] First Embodiment An acoustic wave transmitting and receiving device according to the present disclosure will be described below with reference to FIGS. 1 to 3 are schematic diagrams of an acoustic wave transmitting and receiving device 1 according to the present invention, in which FIG. 1 is a side view, FIG. 2 is a front view, and FIG. 3 is a cross-sectional view taken along line III-III in FIG.

[0013] As shown in FIGS. 1 and 3, the acoustic wave transmitting and receiving device 1 includes a driving element 2 which is a Langevin type wave transmitting and receiving element. The acoustic wave transmitting and receiving device 1 further includes a front mass 3 and a rear mass 4 .

[0014] The driving element 2 has a first end 2A and a second end 2B. A front mass 3 is connected to the first end 2A, and a rear mass 4 is connected to the second end 2B. The driving element 2 is a cylindrical piezoelectric element 5 including PZT (Lead Titanate Zirconate) or the like, with electrodes 2C on both ends, and is driven by an AC voltage supplied from a driving circuit (not shown). The driving element 2 is configured such that a plurality of cylindrical piezoelectric elements 5 are connected along a central axis O extending from a first end 2A to a second end 2B.

[0015] The front mass 3 is made of a lightweight material such as an aluminum alloy. As shown in FIG. 2, the front mass 3 has a hexagonal shape when viewed from the front (the left side in FIG. 1 along the central axis O of the drive element 2). The rear mass 4 is made of a high density material such as steel.

[0016] As shown in FIG. 3, the front mass 3 and rear mass 4 are connected to the cylindrical driving element 2 by tightening bolts 6 that pass through the driving element 2 . When the bolts 6 that connect the front mass 3 and rear mass 4 are tightened, compressive stress is applied to the drive element 2 from both sides, compensating for the low tensile strength. Although a piezoelectric element 5 including a piezoelectric ceramic laminate or the like is used as the driving element 2, it is not limited to this and any element capable of converting electrical signals to mechanical vibrations, such as a magnetostrictive vibrator or a voice coil, can be used. The front surface of the front mass 3 is in contact with an acoustic medium such as water or seawater via a watertight seal material (not shown) such as natural rubber or urethane.

[0017] In such an acoustic wave transmitting and receiving device 1, when a voltage is applied from a driving circuit (not shown) to excite the piezoelectric element 5 of the driving element 2, the entire transmitter / receiver undergoes translational displacement at the frequency of the longitudinal vibration mode, causing the entire device to vibrate greatly. The vibrations generated here are radiated as sound waves to an acoustic medium such as water via a sealing material such as rubber.

[0018] Next, the gap structure formed in the front mass 3 will be described with reference to FIG. The cavity 10 of the front mass 3 has a cavity structure. The void portion 10 has a plurality of voids 11 formed inside the front mass 3, and the front mass 3 has an unfilled structure, thereby reducing the rigidity of the front mass 3. These voids 11 are distributed in the direction away from the first end 2A of the driving element 2 (the direction of arrow A), and each is formed to have a square cross section. The rigidity of the front mass 3 at this time can be designed arbitrarily by adjusting the size of the gap 11 and the overall size of the front mass 3.

[0019] In this front mass 3, the cavity portion 10 including a plurality of cavities 11 distributed in the direction away from the first end 2A of the drive element 2 can lower the frequency of the longitudinal resonance mode of the front mass 3. Furthermore, with such a front mass 3, the resonance mode is lowered in frequency, and the longitudinal vibration mode in which the entire transducer undergoes translational displacement is superimposed on the vibration mode in which the front mass 3 undergoes displacement in the longitudinal direction (direction along the central axis O), thereby enabling the acoustic transmission and reception band to be broadened (as will be described later).

[0020] Next, an analytical model of the acoustic wave transmitting and receiving device 1' according to the present disclosure will be described with reference to FIGS. FIG. 4 is a model of the upper half of the acoustic wave transmitting and receiving device 1' with the center line O as the boundary, and FIG. 5 is a side cross-sectional view showing the entire acoustic wave transmitting and receiving device 1'. In this acoustic wave transmitting and receiving device 1', a gap portion 10' having a plurality of gaps 11' in a ring shape is formed around a center line O as shown in FIG. That is, each gap 11' of the gap portion 10' is formed in a ring shape around the center line O, and has a square cross section perpendicular to the circumferential direction.

[0021] Furthermore, in the acoustic wave transmitting and receiving device 1', the front mass 3' is formed in a circular shape, not a hexagonal shape as shown in FIG. This acoustic wave transmitting and receiving device 1' has the same configuration as the acoustic wave transmitting and receiving device 1 shown in Figs. 1 to 3, except that the shapes of the gap 11' and the front mass 3' are different.

[0022] Also, an acoustic wave transmitting and receiving device 20 having no cavity in the front mass 21 is shown as a comparative example in FIG. This acoustic wave transmitting and receiving device 20 has the same configuration as the acoustic wave transmitting and receiving device 1' described above, except that it does not have a gap.

[0023] The acoustic performance of the acoustic wave transmitting and receiving device 1' according to the present disclosure (see FIGS. 4 to 6) and the acoustic wave transmitting and receiving device 20 according to the comparative example (see FIG. 7) was measured, and the results are summarized in FIG. Figure 8 shows the relationship between frequency [kHz] and transmission voltage sensitivity [dB], where the dotted line (indicated by symbol M) shows the measurement results of the acoustic transmission and reception device 1' according to the present disclosure, and the solid line (indicated by symbol N) shows the measurement results of the acoustic transmission and reception device 20 of the comparative example. In FIG. 8, symbol m1 indicates a longitudinal vibration mode in which the entire acoustic wave transmitting and receiving device serving as a transducer undergoes translational displacement, and symbol m2 indicates a region of a vibration mode in which the front mass undergoes displacement in the longitudinal direction.

[0024] Furthermore, as can be seen from the measurement results shown in Figure 8, in the acoustic wave transmitting and receiving device 1' according to the present disclosure, it can be confirmed that the resonance modes that displace in the longitudinal direction of the front mass 3', particularly the vibration mode (m2), have lower frequencies compared to the measurement results of the acoustic wave transmitting and receiving device 20. As a result, in the acoustic wave transmitting and receiving device 1' according to the present disclosure, the bandwidth of acoustic wave transmission and reception can be widened by superimposing two modes: a longitudinal vibration mode (m1) in which the entire transmitter / receiver undergoes translational displacement, and a vibration mode (m2) in which the front mass 3' undergoes displacement in the longitudinal direction (direction along the central axis O).

[0025] As described in detail above, in the acoustic wave transmitting / receiving device 1 / 1' according to the present disclosure, a void portion 10 / 10' having a plurality of voids 11 / 11' distributed in the direction away from the first end 2A of the driving element 2 (in the direction of arrow A) is formed in the front mass 3 / 3', thereby making it possible to lower the frequency of the resonant mode in the longitudinal direction (direction along the central axis O) of the front mass 3 / 3'. Furthermore, in an acoustic wave transmitting and receiving device 1 / 1' having such a front mass 3 / 3', the frequency of the resonance mode is lowered, and the longitudinal vibration mode (m1) in which the entire transducer undergoes translational displacement is superimposed on the vibration mode (m2) in which the front mass 3 / 3' is displaced in the longitudinal direction, thereby enabling the acoustic wave transmission and reception to be broadened in frequency.

[0026] Moreover, according to one example of this embodiment, the plurality of voids 11 are distributed around the central axis O in a ring shape. Therefore, the anisotropy and periodicity of the distribution of the plurality of voids 11 in the circumferential direction of the central axis O are easily suppressed. With the plurality of voids 11 distributed in such a ring shape, it is possible to achieve a low frequency regardless of the position in the circumferential direction of the central axis O.

[0027] The above embodiment can be modified as follows.

[0028] (Variation 1) Although the gap portion 10 of the front mass 3 of this embodiment has a gap structure, any structure having a plurality of gaps may be used. As a modified example, the cavity 10 of the front mass 3 may have a porous structure. Such a porous structure makes it easy to provide a plurality of dense cavities. As another modification, the cavity 10 of the front mass 3 may include porous metal. A cavity including such porous metal can provide a porous structure with high strength.

[0029] (Variation 2) In the front mass 3 of this embodiment, the structure of the gap portion 10 having the plurality of gaps 11 is not limited to the above, and may be a structure in which holes are simply drilled from the side of the front mass by simple cutting or the like.

[0030] (Variation 3) In this embodiment, the front mass 3 is formed in a hexagonal or circular shape when viewed from the front, but is not limited to this and various shapes can be adopted.

[0031] (Variation 4) In the above embodiment, an example of a Langevin type wave transmitting / receiving element in which the front mass 3 and rear mass 4 are connected to the driving element 2 by fastening the bolt 6 that passes through the driving element 2 is shown, but the present disclosure may also be applied to a Langevin type transducer that is joined by adhesive or the like without bolting.

[0032] (Variation 5) In the above embodiment, the void portion 10 of the front mass 3 is formed by a plurality of voids 11, but in this case, the void portion 10 may have a repeating structure in which a plurality of voids 11 are regularly arranged, such as a gyroid structure, a honeycomb structure, or a lattice structure. According to the void portion 10 in which the plurality of voids 11 are regularly arranged, it is easy to reproduce the distribution of the plurality of voids 11. Therefore, variations in the characteristics of the acoustic wave transmitting and receiving device 1 between products are suppressed.

[0033] Furthermore, the void portion 10 of the front mass 3 may have a structure in which a plurality of voids 11 are irregularly distributed, other than the repeating structure. According to the void portion 10 in which the plurality of voids 11 are irregularly arranged, the anisotropy and periodicity of the distribution of the plurality of voids 11 are likely to be suppressed. This allows the resonance mode of the front mass to be isotropic and wideband low frequency.

[0034] Furthermore, the cavity 10 of the front mass 3 may have a spring structure such as a coil spring in addition to these repeating structures. Such a spring structure reduces the rigidity of the front mass 3 in the same way as a structure having a gap.

[0035] (Variation 6) In the above embodiment, the cross-sectional shape of the gap 11 in the front mass 3 is rectangular, but this is not limitative and the gap 11 may be circular or triangular. Furthermore, the void 10 within the front mass 3 may be a mixture of voids 11 having a cross-sectional shape such as a square, round, or triangular shape.

[0036] Second Embodiment The acoustic wave transmitting and receiving device according to the present disclosure will be described below with reference to FIG. As shown in FIG. 9, the acoustic wave transmitting and receiving device 100 includes a driving element 101, a front mass 102, and a rear mass 103.

[0037] The driving element 101 has a first end 101A and a second end 101B. The front mass 102 includes a gap portion 105 having a plurality of gaps 104 distributed in a direction away from the first end 101A (in the direction of arrow A), and is connected to the first end 101A. Rear mass 103 is coupled to second end 101B.

[0038] According to the acoustic wave transmitting and receiving device 100 as described above, the cavity portion 105 having the plurality of cavities 104 distributed in the direction away from the first end 101A of the driving element 101 is formed in the front mass . Therefore, by adjusting the distribution of the plurality of voids 104, it is possible to control the resonance mode along the direction away from the first end 101A. Therefore, according to the acoustic wave transmitting and receiving device 100, the resonance mode of the front mass 102 can be easily shifted to a lower frequency.

[0039] Third Embodiment A method for constructing an acoustic wave transmitting and receiving device according to the present disclosure will be described below with reference to the above-mentioned FIGS. FIG. 10 is a flowchart showing the steps of a method for constructing an acoustic wave transmitting and receiving device.

[0040] [Step S1] A front mass 102 is formed that includes a cavity portion 105 having a plurality of cavities 104. The front mass 102 is formed using a 3D printer (3-dimensional printer).

[0041] [Step S2] A front mass 102 is connected to the driving element 101 so that a plurality of voids 104 are distributed in a direction away from the first end 101A of the driving element 101 (in the direction of arrow A).

[0042] [Step S3] The construction of the acoustic wave transmitting and receiving device 100 is completed by connecting the rear mass 103 to the second end 101B of the driving element 101.

[0043] In the method of constructing the acoustic wave transmitting and receiving device 100 described above, by forming a void portion 105 in the front mass 102 having a plurality of voids 104 distributed in a direction away from the first end 101A of the driving element 101 (in the direction of arrow A), the resonant mode in the longitudinal direction of the front mass 102 (in the direction along the central axis O) can be made low frequency. Furthermore, in the acoustic wave transmitting and receiving device 100 having such a front mass 102, the frequency of the resonance mode is lowered, and the longitudinal vibration mode (m1) in which the entire transducer undergoes translational displacement is superimposed on the vibration mode (m2) in which the front mass 102 undergoes longitudinal displacement, thereby enabling the acoustic wave transmission and reception to be performed at a wider bandwidth.

[0044] According to one example of the substrate of this embodiment, the front mass is formed by a 3D printer, so that the distribution of the plurality of voids 104 is easily controlled.

[0045] <Fourth embodiment> A method for constructing an acoustic wave transmitting and receiving device according to the present disclosure will be described below with reference to FIG. FIG. 11 is a flowchart showing the steps of a method for constructing an acoustic wave transmitting and receiving device.

[0046] [Step S101] A front mass having a cavity portion with a plurality of cavities 104 is formed.

[0047] [Step S102] A drive element has a first end and a second end, and a front mass is connected to the first end and a rear mass is connected to the second end such that a plurality of air gaps are distributed in a direction away from the first end.

[0048] In the method for constructing an acoustic wave transmitting and receiving device as described above, the front mass includes a gap portion having a plurality of gaps distributed in a direction away from the first end of the driving element. Therefore, by adjusting the distribution of the plurality of voids, it is possible to control the resonance mode along the direction away from the first end. Therefore, with the acoustic wave transmitting and receiving device, the resonance mode of the front mass can be easily shifted to a lower frequency.

[0049] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0050] Some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes.

[0051] (Appendix 1) An acoustic wave transmitting and receiving device comprising: a driving element having a first end and a second end; a gap portion having a plurality of gaps distributed in a direction away from the first end; a front mass connected to the first end; and a rear mass connected to the second end.

[0052] (Appendix 2) 2. The acoustic wave transmitting and receiving device according to claim 1, wherein the void portion has a porous structure.

[0053] (Appendix 3) 3. The acoustic wave transmitting and receiving device according to claim 1, wherein the void portion comprises a porous metal.

[0054] (Appendix 4) 4. The acoustic wave transmitting and receiving device according to any one of claims 1 to 3, wherein the void portion has a gyroid structure, a honeycomb structure, or a lattice structure.

[0055] (Appendix 5) 5. The acoustic wave transmitting and receiving device according to any one of claims 1 to 4, wherein the plurality of voids are regularly distributed.

[0056] (Appendix 6) 6. The acoustic wave transmitting and receiving device according to any one of claims 1 to 5, wherein the plurality of voids are irregularly distributed.

[0057] (Appendix 7) 7. The acoustic wave transmitting and receiving device according to any one of claims 1 to 6, wherein the plurality of voids are distributed in a ring shape around a central axis extending from the first end to the second end.

[0058] (Appendix 8) 8. The acoustic wave transmitting and receiving device according to any one of claims 1 to 7, wherein the gap has a spring structure.

[0059] (Appendix 9) 9. The acoustic wave transmitting and receiving device according to any one of claims 1 to 8, wherein the cross section of the gap is formed in a quadrangular shape.

[0060] (Appendix 10) 10. The acoustic wave transmitting and receiving device according to any one of claims 1 to 9, wherein the cross section of the gap is formed to be round.

[0061] (Appendix 11) 11. The acoustic wave transmitting and receiving device according to any one of claims 1 to 10, wherein the cross section of the gap is formed in a triangular shape.

[0062] (Appendix 12) 12. The acoustic wave transmitting and receiving device according to any one of appendices 1 to 11, wherein the front mass is formed by a 3D printer.

[0063] (Appendix 13) A method for constructing an acoustic wave transmitting and receiving device, comprising: forming a front mass having a gap portion with a plurality of gaps; connecting the front mass to a first end of a driving element having a first end and a second end, and connecting a rear mass to the second end, so that the plurality of gaps are distributed in a direction away from the first end.

[0064] (Appendix 14) 14. A method for constructing an acoustic wave transmitting and receiving device according to claim 13, wherein the front mass is formed using a 3D printer.

[0065] (Appendix 15) 15. The method for constructing an acoustic wave transmitting and receiving device according to claim 13 or 14, wherein the void portion has a porous structure.

[0066] (Appendix 16) 16. The method for constructing an acoustic wave transmitting and receiving device according to any one of claims 13 to 15, wherein the void portion comprises porous metal.

[0067] (Appendix 17) 17. The method for constructing an acoustic wave transmitting and receiving device according to any one of claims 13 to 16, wherein the void portion has a gyroid structure, a honeycomb structure, or a lattice structure.

[0068] (Appendix 18) 18. The method for constructing an acoustic wave transmitting and receiving device according to any one of claims 13 to 17, wherein the plurality of voids are regularly distributed.

[0069] (Appendix 19) 19. The method for constructing an acoustic wave transmitting and receiving device according to any one of appendices 13 to 18, wherein the plurality of voids are irregularly distributed.

[0070] (Appendix 20) 20. The method for constructing an acoustic wave transmitting and receiving device according to any one of appendices 13 to 19, wherein the plurality of voids are distributed in a ring shape around a central axis extending from the first end to the second end.

[0071] (Appendix 21) 21. The method for constructing an acoustic wave transmitting and receiving device according to any one of claims 13 to 20, wherein the gap has a spring structure.

[0072] (Appendix 22) 22. The method for constructing an acoustic wave transmitting and receiving device according to any one of claims 13 to 21, wherein the cross-sectional shape of the gap is formed to be rectangular.

[0073] (Appendix 23) 23. The method for constructing an acoustic wave transmitting and receiving device according to any one of claims 13 to 22, wherein the cross-sectional shape of the gap is formed to be round.

[0074] (Appendix 24) 24. The method for constructing an acoustic wave transmitting and receiving device according to any one of claims 13 to 23, wherein the cross-sectional shape of the gap is formed to be triangular. [Explanation of symbols]

[0075] 1. Acoustic wave transmitting and receiving device 2. Drive element 2A First end 2B Second end 2C electrode 3 Front Mass 3' Front Mass 4 Rear Mass 5 Piezoelectric element 6 volts 10 Cavity 10' void 11 void 11' void 12 Flexural vibration plate 20 Acoustic Transmitting and Receiving Device 21 Front mass 100 Acoustic wave transmitting and receiving device 101 Drive element 101A First end 101B Second end 102 Front Mass 103 Rear Mass 104 void 105 Cavity О Center axis

Claims

1. a drive element having a first end and a second end; a front mass connected to the first end, the front mass including a gap portion having a plurality of gaps distributed in a direction away from the first end; a rear mass coupled to the second end; Equipped with Acoustic wave transmitting and receiving device.

2. The void portion has a porous structure. The acoustic wave transmitting and receiving device according to claim 1 .

3. The void portion has a porous metal. The acoustic wave transmitting and receiving device according to claim 1 or 2.

4. The void portion has a gyroid structure, a honeycomb structure, or a lattice structure. The acoustic wave transmitting and receiving device according to claim 1 or 2.

5. The plurality of voids are regularly distributed. The acoustic wave transmitting and receiving device according to claim 1 or 2.

6. The plurality of voids are irregularly distributed. The acoustic wave transmitting and receiving device according to claim 1 or 2.

7. the plurality of voids are distributed in a ring shape around a central axis extending from the first end to the second end; The acoustic wave transmitting and receiving device according to claim 1 or 2.

8. The gap portion has a spring structure. The acoustic wave transmitting and receiving device according to claim 1 or 2.

9. forming a front mass having a gap portion with a plurality of gaps; a driving element having a first end and a second end, the front mass being connected to the first end and the rear mass being connected to the second end such that the plurality of gaps are distributed in a direction away from the first end; A method for constructing an acoustic wave transmitting and receiving device.

10. Forming the front mass using a 3D printer. A method for constructing the acoustic wave transmitting and receiving device according to claim 9.

Images