CN110639784B - Low frequency narrow beam transducer and transducer method and application - Google Patents

Abstract

The invention proposes a low-frequency narrow beam transducer, an energy conversion method and application, belonging to the technical field of acoustic transducers, and specifically includes a front cover plate and a rear cover plate, and also includes a vibration radiation plate and a piezoelectric ceramic crystal stack , the vibration radiation plate is arranged at the vibration output end of the front cover plate, and the piezoelectric ceramic crystal stack is arranged between the front cover plate and the rear cover plate. The low-frequency narrow beam transducer of the present invention can control the emission voltage response value and the beam width at the resonant frequency of the transducer, realize a small-sized transducer with a low-frequency narrow beam, and make the overall structure and manufacturing process of the transducer device simple and low in cost. , reduce energy consumption.

Description

Low frequency narrow beam transducer and transducer method and application

technical field

The invention belongs to the technical field of acoustic transducers, and in particular relates to a low-frequency narrow-beam transducer and a transducer method and application.

Background technique

With the continuous application of finite element analysis method in transducer design, various new theories and new structures of underwater acoustic transducers emerge one after another. However, piezoelectric transducers are still the focus of current underwater acoustic transducer research. Underwater acoustics mainly studies the transmission, propagation, reception, processing and underwater information transmission technology of underwater sound. Using the propagation of sound waves in water, it can realize the detection, positioning, identification, tracking and underwater communication of underwater targets. Shipping, fish exploration, and development of seabed resources are also of great significance. Because the high-frequency signal has a large loss when transmitted in water, while the low-frequency signal has a small loss and a long distance when transmitted in the water. Therefore, the research of low-frequency transducers has become an important research direction of underwater acoustic transducers. At present, the commonly used methods to reduce the frequency of transducers include bending vibration, liquid cavity resonance and modal coupling.

When using sound waves for underwater detection, the sound waves are generated by the vibration of the transducer wafer, and the narrower the beam width of the sound waves is, the more concentrated the sound field energy is. Accuracy and improving the resolution of imaging have a good effect. The beam width (directivity opening angle) refers to the angle between the corresponding directions in the directional main lobe when the amplitude decreases by 3dB, 6dB, etc. from the maximum value, which are called -3dB beamwidth, -6dB beamwidth, etc. respectively. The size of the beam width of the transducer is related to the size of the radiation surface of the transducer. When the frequency is constant, the beam width of the radiated sound field generated by the larger aperture transducer is smaller; on the contrary, the smaller aperture corresponds to the larger one. beam width. By changing the vibration velocity distribution of the radiation surface of the transducer, the beam width of the sound field radiated by the transducer can be controlled, so that a smaller beam width can be achieved with a smaller aperture size.

SUMMARY OF THE INVENTION

In order to solve the shortcomings of the transducers in the prior art, the present invention provides a low-frequency narrow beam transducer that can realize small size, low frequency and small beam width.

At the same time, the present invention provides a transduction method that can be realized by the above-mentioned low-frequency narrow-beam transducer and a low-frequency narrow-beam transducer device suitable for underwater detection, so as to improve the response level of the emission voltage, and realize the low-frequency and low-frequency operation of the small-sized transducer. The purpose of working within a narrow beam range.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A low-frequency narrow beam transducer, comprising a front cover plate 5 and a rear cover plate 8, it also includes a vibration radiation plate 4 and a piezoelectric ceramic crystal stack, and the vibration radiation plate 4 is arranged at the vibration output end of the front cover plate 5 , the piezoelectric ceramic crystal stack is arranged between the front cover plate 5 and the rear cover plate 8;

The piezoelectric ceramic crystal stack is a cavity structure composed of multiple piezoelectric ceramic groups connected in series. The butterfly-shaped elastic gasket 7 is composed of a butterfly-shaped ring structure, and its flared end is directly opposite to the piezoelectric ceramic ring 6, so that the cavity of the piezoelectric ceramic ring 6 and the upper and lower butterfly-shaped elastic gaskets 7 are empty. The cavity combination forms a vibration cavity whose longitudinal section is a combination of quasi-octagonal units inside the piezoelectric ceramic crystal stack.

The opening diameter of the butterfly-shaped elastic gasket 7 is less than or equal to the outer diameter D1 of the piezoelectric ceramic ring 6, and the angle between the side of the butterfly-shaped elastic gasket 7 and the horizontal plane is 10-20°;

The opening diameter of the butterfly-shaped elastic gasket 7 is 1.5 to 2 times the diameter of the smaller opening at the other end;

The relationship between the diameter D2 of the vibration radiation plate 4 and the diameter D1 of the front cover plate 5 is: D2=D1˜2D1;

Further preferably, the included angle between the side and the bottom of the butterfly-shaped elastic gasket 7 is 11.3°, so that the self-elasticity of the butterfly-shaped elastic gasket 7 can produce a synergistic effect of longitudinal stress and longitudinal vibration.

A transduction method realized by the above-mentioned low-frequency narrow beam transducer, which comprises the following steps:

(1) The piezoelectric ceramic ring 6 is excited to generate radial vibration, the radial vibration stimulates the bottom of the butterfly-shaped elastic gasket 7 to generate bending vibration, and the side wall of the butterfly-shaped elastic gasket 7 converts the bending vibration into longitudinal vibration. The electric ceramic group is connected in series, so that the longitudinal vibration displacement acting on the front cover plate 5 increases and the working frequency decreases;

(2) The longitudinal vibration of the front cover plate 5 acts on the vibration radiation plate 4, and an inner longitudinal vibration is formed on the contact surface of the vibration radiation plate 4 and the front cover plate 5, and the ring of the vibration radiation plate 4 protrudes from the front cover plate 5. Part of the external bending vibration is formed and the phase of the external bending vibration is opposite to the phase of the internal longitudinal vibration. The radiation sound pressure of the two parts of the vibration is superimposed to narrow the beam. The diameter difference between the vibration radiation plate 4 and the front cover plate 5 can be adjusted by adjusting , and adjust the emission voltage response value and beam width of the output end of the vibration radiation plate 4 .

A low-frequency narrow-beam transducer device suitable for underwater detection, which comprises the above-mentioned low-frequency narrow-beam transducer, a casing 1 arranged outside the low-frequency narrow-beam transducer, and a low-frequency narrow beam transducer connected to the The positive lead 12 and the negative lead 11, the polarization directions of the adjacent two piezoelectric ceramic rings 6 of the low-frequency narrow beam transducer are opposite, one side of the piezoelectric ceramic ring 6 is connected to the positive lead 12, and the other side is connected to the negative lead 11 ;Using the cavity type piezoelectric ceramic crystal stack of the low frequency narrow beam transducer to increase the longitudinal vibration displacement and reduce the operating frequency, and then adjust the vibration radiation plate 4 by adjusting the diameter difference between the vibration radiation plate 4 and the front cover plate 5. Transmit voltage response and beamwidth at the output.

It is further limited that the outer surface of the vibration radiation plate 4 of the low-frequency narrow beam transducer is provided with a sound-transmitting rubber layer 2, and a sealed cavity is formed between the sound-transmitting rubber layer 2 and the port of the housing 1, and the low-frequency narrow beam transducer is packaged. in the sealed cavity.

Further limited, the casing 1 is filled with a polyurethane foam layer 3; the positive lead 12 and the negative lead 11 are connected to the cable 13 passing through the bottom of the casing 1, so as to use the polyurethane foam layer 3 to realize the positioning of the low-frequency narrow beam transducer and suspension, making it suitable for sound wave radiation in water.

Further limited, the relationship between the diameter D2 of the vibration radiation plate 4 and the diameter D1 of the front cover plate 5 is: D2=D1～2D1, which ensures that the part of the vibration radiation plate 4 in contact with the front cover plate 5 produces longitudinal vibration, On the other hand, the annular portion on the outer side of the front cover plate 5 generates bending vibration.

Compared with the prior art, the beneficial effects of the present invention are:

The low-frequency narrow-beam transducer of the present invention vibrates longitudinally and radiates sound wave energy outwardly under the excitation of an applied voltage signal. The combination of the transducer, the butterfly-shaped elastic gasket 7 and the piezoelectric ceramic sheet is to reduce the resonant frequency of the transducer. When the vibration radiating plate 4 at the radiation end of the front cover of the transducer is combined, when the longitudinal vibration of the transducer is transmitted. When the vibration radiating plate is reached, it will produce bending vibration, change the directivity of the transducer and the response level of the emission voltage. By adjusting the diameter of the vibration radiating plate, the emission voltage response value and beam width at the resonant frequency of the transducer are controlled to achieve low frequency. The small size transducer with narrow beam makes the overall structure and manufacturing process of the transducer device simple, low cost and energy consumption.

Description of drawings

FIG. 1 is a schematic structural diagram of a low-frequency narrow beam transducer of the present invention.

FIG. 2 is a schematic structural diagram of the piezoelectric ceramic group in FIG. 1 .

FIG. 3 is a mode diagram of a sandwich piezoelectric transducer.

FIG. 4 is a graph showing the emission voltage response curve of the sandwich piezoelectric transducer in water.

FIG. 5 is a directivity diagram of a sandwich piezoelectric transducer in water.

FIG. 6 is a mode shape diagram of a low-frequency small-sized transducer in Embodiment 1 of the present invention.

FIG. 7 is a mode shape diagram of a low-frequency small-sized transducer in Embodiment 2 of the present invention.

FIG. 8 is a mode shape diagram of a low-frequency small-sized transducer in Embodiment 3 of the present invention.

FIG. 9 is a graph showing the emission voltage response curve of the low-frequency small-sized transducer in water in Example 3 of the present invention.

10 is a directivity diagram of a low-frequency small-sized transducer in water in Embodiment 3 of the present invention.

FIG. 11 is a graph of the emission voltage response curve of the low-frequency narrow-beam transducer in water in Embodiment 4 of the present invention.

FIG. 12 is a directivity diagram of a low-frequency narrow beam transducer in water in Embodiment 4 of the present invention.

FIG. 13 is a graph showing the emission voltage response curve of the low-frequency narrow-beam transducer in water in Embodiment 5 of the present invention.

FIG. 14 is a directivity diagram of a low-frequency narrow beam transducer in water in Embodiment 5 of the present invention.

FIG. 15 is a mode shape diagram of a low-frequency narrow beam transducer in Embodiment 6 of the present invention.

FIG. 16 is a sound pressure diagram of a low-frequency narrow beam transducer in water in Embodiment 6 of the present invention.

FIG. 17 is a diagram of the sound pressure level of the low-frequency narrow-beam transducer in water in Embodiment 6 of the present invention.

FIG. 18 is a graph showing the emission voltage response curve of the low-frequency narrow-beam transducer in water in Embodiment 6 of the present invention.

FIG. 19 is a directivity diagram of a low-frequency narrow beam transducer in water in Embodiment 6 of the present invention.

In the picture: 1- Shell, 2- Sound-transmitting rubber layer, 3- Polyurethane foam layer, 4- Vibration radiation plate, 5- Front cover plate, 6- Piezoelectric ceramic ring, 7- Butterfly elastic gasket, 8- Rear Cover plate, 9-bolt, 10-nut, 11-negative lead, 12-positive lead, 13-cable, 14-sealing rubber.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments.

Referring to FIG. 1, the low-frequency narrow beam transducer of the present invention includes a vibration radiation plate 4, a front cover plate 5, a piezoelectric ceramic crystal stack and a rear cover plate 8 arranged in sequence, wherein the front cover plate 5, the piezoelectric ceramic crystal stack The rear cover plate 8 is fixed coaxially with the bolts 9 passing through the shaft center, and the vibration radiation plate 4 is fixed on the vibration output end of the front cover plate 5 by adhesive glue. 30-60mm aluminum circular thin plate, the front cover plate 5 is an aluminum cylindrical shape with a thickness of 35-45mm and a diameter D1 of 20-30mm, the diameter D1 of the front cover plate and the diameter D2 of the vibration radiation plate 4 satisfy the : D2 = 1 to 2D1, the rear cover 8 is a steel cylinder with a thickness of 35 to 45 mm and a diameter of 20 to 30 mm. A piezoelectric ceramic crystal stack is arranged between the rear cover plate 8 and the front cover plate 5, and the piezoelectric ceramic crystal stack is composed of multiple groups of piezoelectric ceramic groups connected in series.

Referring to FIG. 2, the piezoelectric ceramic group is composed of a piezoelectric ceramic ring 6 and butterfly elastic gaskets 7 arranged on both ends of the piezoelectric ceramic ring 6. The piezoelectric ceramic ring 6 is a circular shape made of PZT-4 piezoelectric ceramics. Ring-shaped piezoelectric ceramic ring, butterfly elastic gasket 7 is a butterfly ring structure made of aluminum material, its flared end is directly opposite to piezoelectric ceramic ring 6, and the cavity of piezoelectric ceramic ring 6 is connected to the upper and lower butterfly rings. The combination of the cavities of the shaped elastic gasket 7 forms a vibration cavity with a longitudinal cross-section composed of an octagonal-like unit inside the piezoelectric ceramic stack. The piezoelectric ceramic ring 6 is excited to generate radial vibration, the radial vibration stimulates the bottom of the butterfly-shaped elastic gasket 7 to generate bending vibration, and the side wall of the butterfly-shaped elastic gasket 7 converts the bending vibration into longitudinal vibration. In series, the longitudinal vibration displacement acting on the front cover plate 5 is increased, and the operating frequency is decreased. By adjusting the geometric dimensions of the piezoelectric ceramic ring 6 and the butterfly-shaped elastic gasket 7, transducers with different resonant frequencies can be obtained without changing the thickness.

It is further limited that the diameter of the opening of the butterfly-shaped elastic gasket 7 is less than or equal to the outer diameter of the piezoelectric ceramic ring 6, and the opening diameter of the butterfly-shaped elastic gasket 7 is 1.5 to 2 times the diameter of the smaller opening at the other end. The angle between the side part and the bottom part of the gasket 7 is 10-20°, preferably 11.3°.

The transduction method realized by the above-mentioned low-frequency narrow beam transducer includes the following steps:

(1) The piezoelectric ceramic ring 6 is excited to generate radial vibration, the radial vibration stimulates the bottom of the butterfly-shaped elastic gasket 7 to generate bending vibration, and the side wall of the butterfly-shaped elastic gasket 7 converts the bending vibration into longitudinal vibration. The electric ceramic group is connected in series, so that the longitudinal vibration displacement acting on the front cover plate 5 increases and the working frequency decreases;

(2) The longitudinal vibration of the front cover plate 5 acts on the vibration radiation plate 4, and an inner longitudinal vibration is formed on the contact surface of the vibration radiation plate 4 and the front cover plate 5, and the ring of the vibration radiation plate 4 protrudes from the front cover plate 5. Part of the external bending vibration is formed and the phase of the external bending vibration is opposite to the phase of the internal longitudinal vibration. The radiation sound pressure of the two parts of the vibration is superimposed to narrow the beam. The diameter difference between the vibration radiation plate 4 and the front cover plate 5 can be adjusted by adjusting , and adjust the emission voltage response value and beam width of the output end of the vibration radiation plate 4 .

Because the low frequency narrow beam transducer has the advantages of low frequency, small size and narrow beam, it can be made into a low frequency narrow beam transducer device suitable for underwater detection.

The low frequency narrow beam transducer device suitable for underwater detection includes a casing 1 , a low frequency narrow beam transducer, a positive lead 12 , a negative lead 11 , a sound-transmitting rubber layer 2 , a polyurethane foam layer 3 and a cable 13 .

The interior of the casing 1 is filled with a polyurethane foam layer 3, and the positioning and suspension of the low-frequency narrow-beam transducer is realized by using the polyurethane foam layer 3, so that it is suitable for sound wave radiation in water. A sound-transmitting rubber layer 2 is arranged at the port of the casing 1, so that a sealed cavity is formed between the sound-transmitting rubber layer 2 and the port of the casing 1, and the low-frequency narrow beam transducer is encapsulated in the sealed cavity. The vibration radiation plate 4 of the low-frequency narrow beam transducer is directly opposite to the sound-transmitting rubber layer 2, and the polarization directions of the adjacent two piezoelectric ceramic rings 6 of the low-frequency narrow beam transducer are opposite, and one side of the piezoelectric ceramic rings 6 is connected. The positive lead 12 is connected to the negative lead 11 on the other side, and the positive lead 12 and the negative lead 11 are connected to the cable 13 passing through the bottom of the casing 1 . In order to ensure the sealing effect, a sealing rubber 14 is provided at the connection between the cable 13 and the casing 1 . Under the condition that the thicknesses of the piezoelectric ceramic crystal stack, the front cover 5 and the rear cover 8 are kept unchanged, the polarization directions of the two adjacent piezoelectric ceramic rings 6 are opposite. The geometric dimensions of the elastic gasket 7 can obtain transducers with different resonant frequencies without changing the thickness. Voltage response value and beam width, that is, adjusting the transmit voltage response value and beam width of the transducer.

Example 1

The low-frequency small-sized transducer of this embodiment includes a front cover plate 5 , a piezoelectric ceramic ring 6 , a butterfly-shaped elastic gasket 7 , a rear cover plate 8 , bolts 9 , and nuts 10 . Among them, the front cover plate 5 and the butterfly elastic gasket 7 are made of aluminum material, and the rear cover plate 8, the bolts 9 and the nuts 10 are made of steel materials. The bolt 9 penetrates the rear cover plate 8, the piezoelectric ceramic ring 6, the butterfly elastic gasket 7 and extends into the front cover plate 5 to a certain depth, so that the rear cover plate 8 and the front cover plate 5 are connected in series into an integrated structure, and the middle part is connected to the front cover plate 5. The butterfly-shaped elastic gaskets 7 connecting the rear cover plate 8 and the front cover plate 5 are respectively bonded by adhesive. A nut 10 is installed at the bottom of the bolt 9 for fastening.

The piezoelectric ceramic crystal stack of this embodiment is composed of 4 groups of piezoelectric ceramic groups connected in series, and each group of piezoelectric ceramic groups is a circular piezoelectric ceramic ring 6 and 2 made of one PZT-4 piezoelectric ceramic. The butterfly-shaped elastic gaskets 7 respectively disposed on the two ends of the piezoelectric ceramic ring are bonded together as a whole. The butterfly-shaped elastic gasket 7 in this embodiment is a butterfly-shaped ring structure made of aluminum material, and its flared end is connected to the piezoelectric ceramic ring. The ceramic rings are facing each other, so that the cavity of the piezoelectric ceramic ring 6 and the cavity of the upper and lower butterfly-shaped elastic spacers 7 are combined to form a vibration cavity whose longitudinal section is a combination of octagonal units.

The thickness of the front cover plate 5 in this embodiment is 45 mm and the diameter D1 is 30 mm, and the thickness of the rear cover plate 8 is 39 mm and the diameter is 30 mm. The outer diameter of the piezoelectric ceramic ring is 30mm, the inner diameter is 24mm, the opening diameter of the butterfly elastic gasket 7 is 24mm, the diameter of the smaller opening is 18mm, and the angle between the side and the bottom of the butterfly elastic gasket 7 is 18.26°.

Example 2

The low-frequency small-sized transducer of this embodiment includes a front cover plate 5 , a piezoelectric ceramic ring 6 , a butterfly-shaped elastic gasket 7 , a rear cover plate 8 , bolts 9 , and nuts 10 . Among them, the front cover plate 5 and the butterfly elastic gasket 7 are made of aluminum material, and the rear cover plate 8, the bolts 9 and the nuts 10 are made of steel materials. The bolt 9 penetrates the rear cover plate 8, the piezoelectric ceramic ring 6, the butterfly elastic gasket 7 and extends into the front cover plate 5 to a certain depth, so that the rear cover plate 8 and the front cover plate 5 are connected in series into an integrated structure, and the middle part is connected to the front cover plate 5. The butterfly-shaped elastic gaskets 7 connecting the rear cover plate 8 and the front cover plate 5 are respectively bonded by adhesive. A nut 10 is installed at the bottom of the bolt 9 for fastening.

The piezoelectric ceramic crystal stack of this embodiment is composed of 4 groups of piezoelectric ceramic groups connected in series, and each group of piezoelectric ceramic groups is a circular piezoelectric ceramic ring 6 and 2 made of one PZT-4 piezoelectric ceramic. The butterfly-shaped elastic gaskets 7 respectively disposed on the two ends of the piezoelectric ceramic ring are bonded together as a whole. The butterfly-shaped elastic gasket 7 in this embodiment is a butterfly-shaped ring structure made of aluminum material, and its flared end is connected to the piezoelectric ceramic ring. The ceramic rings are facing each other, so that the cavity of the piezoelectric ceramic ring 6 and the cavity of the upper and lower butterfly-shaped elastic spacers 7 are combined to form a vibration cavity whose longitudinal section is a combination of octagonal units.

The thickness of the front cover plate 5 in this embodiment is 45 mm and the diameter D1 is 30 mm, and the thickness of the rear cover plate 8 is 39 mm and the diameter is 30 mm. The outer diameter of the piezoelectric ceramic ring is 30mm, the inner diameter is 22mm, the opening diameter of the butterfly elastic gasket 7 is 22mm, the diameter of the smaller opening is 14mm, and the angle between the side and the bottom of the butterfly elastic gasket 7 is 14°.

Example 3

The low-frequency small-sized transducer of this embodiment includes a front cover plate 5 , a piezoelectric ceramic ring 6 , a butterfly-shaped elastic gasket 7 , a rear cover plate 8 , bolts 9 , and nuts 10 . Among them, the front cover plate 5 and the butterfly elastic gasket 7 are made of aluminum material, and the rear cover plate 8, the bolts 9 and the nuts 10 are made of steel materials. The bolt 9 penetrates the rear cover plate 8, the piezoelectric ceramic ring 6, the butterfly elastic gasket 7 and extends into the front cover plate 5 to a certain depth, so that the rear cover plate 8 and the front cover plate 5 are connected in series into an integrated structure, and the middle part is connected to the front cover plate 5. The butterfly-shaped elastic gaskets 7 connecting the rear cover plate 8 and the front cover plate 5 are respectively bonded by adhesive. A nut 10 is installed at the bottom of the bolt 9 for fastening.

The piezoelectric ceramic crystal stack of this embodiment is composed of 4 groups of piezoelectric ceramic groups connected in series, and each group of piezoelectric ceramic groups is a circular piezoelectric ceramic ring 6 and 2 made of one PZT-4 piezoelectric ceramic. The butterfly-shaped elastic gaskets 7 respectively disposed on the two ends of the piezoelectric ceramic ring are bonded together as a whole. The butterfly-shaped elastic gasket 7 in this embodiment is a butterfly-shaped ring structure made of aluminum material, and its flared end is connected to the piezoelectric ceramic ring. The ceramic rings are facing each other, so that the cavity of the piezoelectric ceramic ring 6 and the cavity of the upper and lower butterfly-shaped elastic spacers 7 are combined to form a vibration cavity whose longitudinal section is a combination of octagonal units.

The thickness of the front cover plate 5 in this embodiment is 45 mm and the diameter D1 is 30 mm, and the thickness of the rear cover plate 8 is 39 mm and the diameter is 30 mm. The outer diameter of the piezoelectric ceramic ring is 30mm, the inner diameter is 20mm, the opening diameter of the butterfly elastic gasket 7 is 20mm, the diameter of the smaller opening is 10mm, and the angle between the side and the bottom of the butterfly elastic gasket 7 is 11.3°.

Example 4

The low-frequency narrow beam transducer device of this embodiment includes a casing 1, a sound-transmitting rubber layer 2, a polyurethane foam layer 3, a vibration radiation plate 4, a front cover 5, a piezoelectric ceramic ring 6, a butterfly-shaped elastic gasket 7, and a rear cover Plate 8 , bolts 9 , nuts 10 , negative lead 11 , positive lead 12 and cable 13 .

The housing 1 is made of aluminum alloy, the front cover 5, butterfly elastic gasket 7 and vibration radiation plate 4 are made of aluminum, and the rear cover 8, bolts 9 and nuts 10 are made of steel. A hole is opened at the bottom of the casing 1 to allow the cable 13 to pass through, and the opening is sealed with a sealing rubber 14 . The bolt 9 penetrates the rear cover plate 8, the piezoelectric ceramic ring 6, the butterfly elastic gasket 7 and extends into the front cover plate 5 to a certain depth, so that the rear cover plate 8 and the front cover plate 5 are connected in series into an integrated structure, and the middle part is connected to the front cover plate 5. The butterfly-shaped elastic gaskets 7 connecting the rear cover plate 8 and the front cover plate 5 are respectively bonded by adhesive. A nut 10 is installed at the bottom of the bolt 9 for fastening.

The piezoelectric ceramic crystal stack of this embodiment is composed of 4 groups of piezoelectric ceramic groups connected in series, and each group of piezoelectric ceramic groups is a circular piezoelectric ceramic ring 6 and 2 made of one PZT-4 piezoelectric ceramic. The butterfly-shaped elastic gaskets 7 respectively disposed on the two ends of the piezoelectric ceramic ring are bonded together as a whole. The butterfly-shaped elastic gasket 7 in this embodiment is a butterfly-shaped ring structure made of aluminum material, and its flared end is connected to the piezoelectric ceramic ring. The ceramic rings are facing each other, so that the cavity of the piezoelectric ceramic ring 6 and the cavity of the upper and lower butterfly-shaped elastic spacers 7 are combined to form a vibration cavity whose longitudinal section is a combination of octagonal units.

The vibration radiation plate 4 of this embodiment is an aluminum circular thin plate with a thickness of 2 mm and a diameter D2 of 40 mm. The thickness of the front cover plate 5 is 45 mm and the diameter D1 is 30 mm, which satisfies the diameter D2 of the vibration radiation plate 4: D2= Any one of 1 to 2D1 may be used. The thickness of the rear cover plate 8 is 39 mm and the diameter is 30 mm. The outer diameter of the piezoelectric ceramic ring is 30mm, the inner diameter is 20mm, the opening diameter of the butterfly elastic gasket 7 is 20mm, the diameter of the smaller opening is 10mm, and the angle between the side and the bottom of the butterfly elastic gasket 7 is 11.3°.

Example 5

The low-frequency narrow beam transducer device of this embodiment includes a casing 1, a sound-transmitting rubber layer 2, a polyurethane foam layer 3, a vibration radiation plate 4, a front cover 5, a piezoelectric ceramic ring 6, a butterfly-shaped elastic gasket 7, and a rear cover Plate 8 , bolts 9 , nuts 10 , negative lead 11 , positive lead 12 and cable 13 .

The housing 1 is made of aluminum alloy, the front cover 5, butterfly elastic gasket 7 and vibration radiation plate 4 are made of aluminum, and the rear cover 8, bolts 9 and nuts 10 are made of steel. A hole is opened at the bottom of the casing 1 to allow the cable 13 to pass through, and the opening is sealed with a sealing rubber 14 . The bolt 9 penetrates the rear cover plate 8, the piezoelectric ceramic ring 6, the butterfly elastic gasket 7 and extends into the front cover plate 5 to a certain depth, so that the rear cover plate 8 and the front cover plate 5 are connected in series into an integrated structure, and the middle part is connected to the front cover plate 5. The butterfly-shaped elastic gaskets 7 connecting the rear cover plate 8 and the front cover plate 5 are respectively bonded by adhesive. A nut 10 is installed at the bottom of the bolt 9 for fastening.

The piezoelectric ceramic crystal stack of this embodiment is composed of 4 groups of piezoelectric ceramic groups connected in series, and each group of piezoelectric ceramic groups is a circular piezoelectric ceramic ring 6 and 2 made of one PZT-4 piezoelectric ceramic. The butterfly-shaped elastic gaskets 7 respectively disposed on the two ends of the piezoelectric ceramic ring are bonded together as a whole. The butterfly-shaped elastic gasket 7 in this embodiment is a butterfly-shaped ring structure made of aluminum material, and its flared end is connected to the piezoelectric ceramic ring. The ceramic rings are facing each other, so that the cavity of the piezoelectric ceramic ring 6 and the cavity of the upper and lower butterfly-shaped elastic spacers 7 are combined to form a vibration cavity whose longitudinal section is a combination of octagonal units.

The vibration radiation plate 4 of this embodiment is an aluminum circular thin plate with a thickness of 2 mm and a diameter D2 of 50 mm. The thickness of the front cover plate 5 is 45 mm and the diameter D1 is 30 mm. The diameter D2 of the vibration radiation plate 4 satisfies: D2= Any one of 1 to 2D1 may be used. The thickness of the rear cover plate 8 is 39 mm and the diameter is 30 mm. The outer diameter of the piezoelectric ceramic ring is 30mm, the inner diameter is 20mm, the opening diameter of the butterfly elastic gasket 7 is 20mm, the diameter of the smaller opening is 10mm, and the angle between the side and the bottom of the butterfly elastic gasket 7 is 11.3°.

Example 6

The low-frequency narrow beam transducer device of this embodiment includes a casing 1, a sound-transmitting rubber layer 2, a polyurethane foam layer 3, a vibration radiation plate 4, a front cover 5, a piezoelectric ceramic ring 6, a butterfly-shaped elastic gasket 7, and a rear cover Plate 8 , bolts 9 , nuts 10 , negative lead 11 , positive lead 12 and cable 13 .

The housing 1 is made of aluminum alloy, the front cover 5, butterfly elastic gasket 7 and vibration radiation plate 4 are made of aluminum, and the rear cover 8, bolts 9 and nuts 10 are made of steel. A hole is opened at the bottom of the casing 1 to allow the cable 13 to pass through, and the opening is sealed with a sealing rubber 14 . The bolt 9 penetrates the rear cover plate 8, the piezoelectric ceramic ring 6, the butterfly elastic gasket 7 and extends into the front cover plate 5 to a certain depth, so that the rear cover plate 8 and the front cover plate 5 are connected in series into an integrated structure, and the middle part is connected to the front cover plate 5. The butterfly-shaped elastic gaskets 7 connecting the rear cover plate 8 and the front cover plate 5 are respectively bonded by adhesive. A nut 10 is installed at the bottom of the bolt 9 for fastening.

The piezoelectric ceramic crystal stack of this embodiment is composed of 4 groups of piezoelectric ceramic groups connected in series, and each group of piezoelectric ceramic groups is a circular piezoelectric ceramic ring 6 and 2 made of one PZT-4 piezoelectric ceramic. The butterfly-shaped elastic gaskets 7 respectively disposed on the two ends of the piezoelectric ceramic ring are bonded together as a whole. The butterfly-shaped elastic gasket 7 in this embodiment is a butterfly-shaped ring structure made of aluminum material, and its flared end is connected to the piezoelectric ceramic ring. The ceramic rings are facing each other, so that the cavity of the piezoelectric ceramic ring 6 and the cavity of the upper and lower butterfly-shaped elastic spacers 7 are combined to form a vibration cavity whose longitudinal section is a combination of octagonal units.

The vibration radiation plate 4 of this embodiment is an aluminum circular thin plate with a thickness of 2 mm and a diameter D2 of 53 mm. The thickness of the front cover plate 5 is 45 mm and the diameter D1 is 30 mm. The diameter D2 of the vibration radiation plate 4 satisfies: D2= Any one of 1 to 2D1 may be used. The thickness of the rear cover plate 8 is 39 mm and the diameter is 30 mm. The outer diameter of the piezoelectric ceramic ring is 30mm, the inner diameter is 20mm, the opening diameter of the butterfly elastic gasket 7 is 20mm, the diameter of the smaller opening is 10mm, and the angle between the side and the bottom of the butterfly elastic gasket 7 is 11.3°.

Figure 3, Figure 4, Figure 5 are the mode shape of the sandwich piezoelectric transducer, the emission voltage response curve and the directivity diagram in water, respectively.

6 , 7 , and 8 are respectively the mode shape diagrams of the low-frequency small-sized transducers (that is, the transducers without the vibration radiating plate 4 ) in Embodiments 1, 2, and 3 of the present invention. Comparing Fig. 3 with Fig. 6, Fig. 7, Fig. 8, it can be seen that the resonant frequency of the low-frequency small-sized transducer in Example 3 is 8658 Hz lower than that of the sandwich transducer, and from the comparison of the size data of Examples 1-3 It can be seen that changing the size of the butterfly gasket and the piezoelectric ceramic ring can change the frequency of the transducer.

FIG. 9 and FIG. 10 are respectively the emission voltage response curve and the directivity diagram of the low-frequency small-sized transducer in water in Embodiment 3 of the present invention. Comparing FIG. 4 and FIG. 9 , it can be seen that the emission voltage response value at the resonance frequency of the low-frequency small-sized transducer in Example 3 is reduced by 14.67 dB compared with that of the sandwich transducer. According to the definition of the beam width, it can be seen from Fig. 5 and Fig. 10 that the -3dB beam width at the resonance frequency of the low-frequency small-sized transducer and the sandwich transducer in Example 3 are both 180°.

FIG. 11 , FIG. 13 , and FIG. 18 are respectively the emission voltage response curves of the low-frequency narrow-beam transducers in water in Embodiments 4, 5, and 6 of the present invention. Comparing each emission voltage response curve, it can be seen that the emission voltage response value at the resonant frequency of the low-frequency narrow beam transducer in Example 6 is the largest, which is increased by 5.2 dB compared with the sandwich transducer, and the low-frequency small size in Example 3 is changed. Compared with the energizer, it increases by 19.87dB. By changing the diameter of the vibration radiation plate 4, the maximum emission voltage response value and the minimum beam width can be adjusted and changed.

FIG. 12 , FIG. 14 , and FIG. 19 are the directivity diagrams of the low-frequency narrow-beam transducers in water in Embodiments 4, 5, and 6 of the present invention, respectively. According to the definition of beam width, it can be seen from Figure 12, Figure 14, and Figure 19 that the -3dB beam width at the resonance frequency of the low-frequency narrow beam transducer in Embodiments 4, 5, and 6 are 180°, 92.6°, and 44.6°, respectively.

FIG. 15 , FIG. 16 , and FIG. 17 are respectively the mode shape diagram, the sound pressure diagram and the sound pressure level diagram of the low-frequency narrow beam transducer in Embodiment 6 of the present invention. It can be seen from FIG. 15 that when the longitudinal vibration of the transducer is transmitted to the vibration radiation plate 4, the center part of the vibration radiation plate 4 is subjected to longitudinal vibration, and the edge part is subjected to bending vibration.

In summary, the piezoelectric ceramic crystal stack formed by the combination of the plurality of piezoelectric ceramic rings 6 and the butterfly-shaped elastic gasket 7 of the present invention is combined with the disc-shaped vibration radiation plate 4, so that the longitudinal vibration and the bending vibration can be superimposed, so as to improve the performance. The emission voltage response stage narrows the beam at the output end. By adjusting the diameter of the vibrating radiation plate 4, the emission voltage response value and beam width at the resonant frequency of the transducer are controlled, so as to realize the small-sized transducer within the range of low frequency and narrow beam. Work.

Claims (7)

1. A low frequency narrow beam transducer comprising a front cover plate (5) and a back cover plate (8), characterized in that: the vibration radiation plate (4) is arranged at the vibration output end of the front cover plate (5), and the piezoelectric ceramic crystal pile is arranged between the front cover plate (5) and the rear cover plate (8);

the piezoelectric ceramic crystal stack is of a cavity type structure consisting of a plurality of groups of piezoelectric ceramic groups which are connected in series, each piezoelectric ceramic group consists of a piezoelectric ceramic ring (6) and butterfly-shaped elastic gaskets (7) arranged on the upper end surface and the lower end surface of the piezoelectric ceramic ring (6), each butterfly-shaped elastic gasket (7) is of a butterfly-shaped ring structure, the flared end of each butterfly-shaped elastic gasket is opposite to the piezoelectric ceramic ring (6), and the cavity of each piezoelectric ceramic ring (6) and the cavities of the upper and lower butterfly-shaped elastic gaskets (7) are combined in the piezoelectric ceramic crystal stack to form a vibration cavity with an octagonal unit combined longitudinal section;

the opening diameter of the butterfly elastic gasket (7) is smaller than or equal to the outer diameter D1 of the piezoelectric ceramic ring (6), and the included angle between the side part of the butterfly elastic gasket (7) and the horizontal plane is 10-20 degrees;

the diameter of an opening of the butterfly elastic gasket (7) is 1.5-2 times of that of a smaller opening at the other end;

the relation between the diameter D2 of the vibration radiation plate 4 and the diameter D1 of the front cover plate (5) is: d2 is D1 ~ 2D 1.

2. The low frequency narrow beam transducer of claim 1, wherein: the included angle between the side part and the bottom part of the butterfly-shaped elastic gasket (7) is 11.3 degrees.

3. A method of transduction by a low frequency narrow beam transducer according to claim 1, characterized by the steps of:

(1) the piezoelectric ceramic rings (6) are excited to generate radial vibration, the bottom of the butterfly elastic gasket (7) is excited to generate bending vibration by the radial vibration, the bending vibration is converted into longitudinal vibration by the side wall of the butterfly elastic gasket (7), and the multiple groups of piezoelectric ceramic groups are connected in series, so that the longitudinal vibration displacement acting on the front cover plate (5) is increased, and the working frequency is reduced;

(2) the longitudinal vibration action of the front cover plate (5) is used on the vibration radiation plate (4), the inner longitudinal vibration is formed on the contact surface of the vibration radiation plate (4) and the front cover plate (5), the outer bending vibration is formed on the annular part of the vibration radiation plate (4) protruding out of the front cover plate (5), the phase of the outer bending vibration is opposite to that of the inner longitudinal vibration, the radiation sound pressures of the two parts of vibration are superposed to narrow a wave beam, and the transmission voltage response value and the wave beam width of the output end of the vibration radiation plate (4) can be adjusted and controlled by adjusting the diameter difference of the vibration radiation plate (4) and the front cover plate (5).

4. A low-frequency narrow-beam transducer device suitable for underwater exploration, characterized in that: the low-frequency narrow-beam transducer comprises the low-frequency narrow-beam transducer as claimed in claim 1, a housing (1) arranged outside the low-frequency narrow-beam transducer, and a positive electrode lead (12) and a negative electrode lead (11) connected to the low-frequency narrow-beam transducer, wherein the polarization directions of two adjacent piezoelectric ceramic rings (6) of the low-frequency narrow-beam transducer are opposite, one surface of each piezoelectric ceramic ring (6) is connected with the positive electrode lead (12), and the other surface of each piezoelectric ceramic ring is connected with the negative electrode lead (11); the longitudinal vibration displacement is increased and the working frequency is reduced by utilizing the cavity type piezoelectric ceramic crystal stack of the low-frequency narrow-beam transducer, and the emission voltage response value and the beam width of the output end of the vibration radiation plate (4) are regulated and controlled by regulating the diameter difference value of the vibration radiation plate (4) and the front cover plate (5).

5. The low frequency narrow beam transducer apparatus adapted for underwater exploration of claim 4, wherein: the outer surface of a vibration radiation plate (4) of the low-frequency narrow-beam transducer is provided with an acoustic transmission rubber layer (2), a sealing cavity is formed between the acoustic transmission rubber layer (2) and a port of the shell (1), and the low-frequency narrow-beam transducer is packaged in the sealing cavity.

6. The low frequency narrow beam transducer apparatus adapted for underwater exploration of claim 4, wherein: the shell (1) is filled with a polyurethane foam layer (3); the positive lead (12) and the negative lead (11) are connected with a cable (13) penetrating through the bottom of the shell (1).

7. The low frequency narrow beam transducer apparatus adapted for underwater exploration of claim 4, wherein: the relation between the diameter D2 of the vibration radiation plate (4) and the diameter D1 of the front cover plate (5) is: d2 is D1 ~ 2D 1.

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