CN214052411U - Piezoelectric patch and ultrasonic transducer for gas flow measurement - Google Patents

Abstract

The utility model discloses a piezoelectric patches and be used for ultrasonic transducer of gas flow measurement. A piezoelectric piece comprises a piezoelectric body with a rectangular section, and is characterized in that the piezoelectric body is divided into a plurality of strip-shaped piezoelectric vibrators only the bottoms of which are connected together to form a common connection surface by a plurality of parallel gaps, and the width of the piezoelectric vibrator positioned on the inner side is not equal to that of the piezoelectric vibrator positioned on the outer side. The utility model provides a piezoelectric patch comprises the piezoelectric vibrator of the bar of the different width, constitutes inhomogeneous piezoelectric vibrator array, because its piezoelectric vibrator width is different, and the resonant frequency of the piezoelectric vibrator of the difference in width is different to can constitute multifrequency resonance system, can obtain than the wideer work bandwidth of even piezoelectric vibrator array.

Description

Piezoelectric patch and ultrasonic transducer for gas flow measurement

Technical Field

The utility model relates to a piezoelectric patch still relates to an ultrasonic transducer who is used for gas flow measurement who utilizes above-mentioned piezoelectric patch, belongs to ultrasonic wave gas flow measuring device technical field.

Background

An ultrasonic transducer for gas flow measurement, the basic components of which comprise: a piezoelectric patch, a matching layer, a backing and a housing, one of the key components of which is the piezoelectric patch. For the transducer with the working frequency more than 300kHz, the adopted piezoelectric sheet is generally uniformly slotted on the cubic piezoelectric sheet to form a uniform array of strip-shaped vibrators, namely, the length of the side isaHas a thickness ofhThe cubic piezoelectric plate is provided with a plurality of gaps, the piezoelectric plate with the square cross section is divided into a plurality of strip-shaped vibrators which are uniformly distributed, and the strip-shaped vibrators form a uniform array. The size and piezoelectric parameters of the cubic piezoelectric sheet, the number, size, slotting depth and width of the uniform strip-shaped vibrators determine the working frequency, directivity, sensitivity, bandwidth and the like of the ultrasonic wave. The piezoelectric patch of the uniform array of the strip-shaped vibrators has the defect of relatively narrow working bandwidth, and the application range of the ultrasonic transducer is influenced. In addition, the existing ultrasonic transducer has the defect that the assembly of each component in the transducer is inconvenient in structure.

Disclosure of Invention

To the above-mentioned defect that exists among the prior art, the utility model provides a piezoelectric patch with the work bandwidth of broad.

The utility model discloses a realize through following technical scheme: a piezoelectric piece comprises a piezoelectric body with a rectangular section, and is characterized in that the piezoelectric body is divided into a plurality of strip-shaped piezoelectric vibrators only the bottoms of which are connected together to form a common connection surface by a plurality of parallel gaps, and the width of the piezoelectric vibrator positioned on the inner side is not equal to that of the piezoelectric vibrator positioned on the outer side.

The utility model discloses in, its resonant frequency of the piezoelectric vibrator that the width is different to can constitute multifrequency resonance system. By adjusting the size of the piezoelectric vibrators and the width and depth of the gaps among the piezoelectric vibrators, the working bandwidth wider than that of a uniform piezoelectric vibrator array can be obtained under the condition of meeting the requirements of working frequency, sensitivity and other relevant performances. The structure that the bottom of piezoelectric vibrator links to each other is convenient for piezoelectric vibrator's processing and assembly.

Further, the width of the piezoelectric vibrator is gradually increased or gradually decreased from the middle to two sides; or the width of the piezoelectric vibrator is increased or decreased from the middle to two sides according to a certain gradient. The piezoelectric vibrator has the advantages that: the width is gradually changed, the resonance frequency is gradually changed, and the synthetic frequency response is good.

Furthermore, the piezoelectric vibrators are symmetrically distributed on the central line of the piezoelectric body or on two sides of the middle piezoelectric vibrator. The pattern is such that its pattern is symmetrical about the normal center of the array plane.

Furthermore, the number of the piezoelectric vibrators is 3-8.

In order to ensure that the frequency characteristic, the sensitivity and other related parameters meet the requirements and reduce the processing difficulty, the width of the gap between the piezoelectric vibrators is 0.1mm-0.5 mm; the depth of the gap between the piezoelectric vibrators is 70-90% of the thickness of the piezoelectric sheet.

The utility model also provides an adopt the ultrasonic transducer who is used for gas flow measurement of foretell piezoelectric patches, the technical scheme of its adoption is: the utility model provides an ultrasonic transducer for gas flow measurement, includes the transducer casing, sets gradually backing material layer, piezoelectric patch, matching layer in the transducer casing from bottom to top, characterized by: the piezoelectric patch is any one of the piezoelectric patches, a common connection surface of the piezoelectric patch is positioned at the lower part and is in contact with the backing material layer, a piezoelectric patch fixing box made of metal is further arranged between the matching layer and the piezoelectric patch, the piezoelectric patch fixing box is a rectangular box which is provided with a top surface and is matched with the piezoelectric patch, the piezoelectric patch fixing box is covered on the piezoelectric patch, the top surface of the piezoelectric patch fixing box is used for connecting the top surface of the piezoelectric vibrator to form a common electrode, a first signal wire is connected to the common connection surface of the piezoelectric patch, and a second signal wire is connected to the piezoelectric patch fixing box.

The utility model discloses in, because the piezoelectric vibrator width of its piezoelectric patches is different, and the resonant frequency of the piezoelectric vibrator of width difference is different to can constitute multifrequency resonance system, can obtain than the wideer work bandwidth of even piezoelectric vibrator array. The utility model discloses well fixed box of piezoelectric patches who adopts can make things convenient for the installation and the location of piezoelectric patches through the fixed box of piezoelectric patches on the one hand, reduces the assembly degree of difficulty, and on the other hand can form common electrode through the top surface of the fixed box of piezoelectric patches and being connected of each piezoelectric vibrator, can simplify structural design and reduce the assembly degree of difficulty.

Furthermore, an ear-shaped structure is arranged on the side wall of the piezoelectric patch fixing box, and the second signal line is connected with the ear-shaped structure. The second signal line is connected with the ear-shaped structure of the piezoelectric patch fixing box, the area of a heat conduction path is small, and welding is facilitated.

Further, for the installation of the piezoelectric patch fixing box and the fixation, the lower end of the piezoelectric patch fixing box is provided with an edge protruding outwards, the middle part of the inner side of the transducer shell is a square cavity structure matched with the piezoelectric patch fixing box, and an embedded groove matched with the edge of the piezoelectric patch fixing box is formed in the side wall of the square cavity structure.

Furthermore, the upper part and the lower part of the inner side of the transducer shell are respectively provided with a cylindrical cavity structure which is coaxial with the square cavity structure. The utility model discloses in two that set up cylindrical cavity structures is used for installing matching layer and backing material layer respectively, can be convenient for the assembly on matching layer and backing material layer, can guarantee that matching layer, piezoelectric patches, backing material layer are coaxial simultaneously.

Furthermore, a transducer rear cover is arranged and is arranged at the lower end of the transducer shell in a sealing mode. The transducer rear cover is arranged to replace the traditional glue pouring process, so that the assembly process is simple and easy to implement.

The utility model has the advantages that: the utility model provides a piezoelectric patch comprises the piezoelectric vibrator of the bar of the different width, constitutes inhomogeneous piezoelectric vibrator array, because its piezoelectric vibrator width is different, and the resonant frequency of the piezoelectric vibrator of the difference in width is different to can constitute multifrequency resonance system, can obtain than the wideer work bandwidth of even piezoelectric vibrator array. The utility model provides an ultrasonic transducer, owing to adopted inhomogeneous piezoelectric vibrator array, its working bandwidth is wider than the working bandwidth of even piezoelectric vibrator array, and accommodation is bigger, simultaneously, the utility model discloses an adopt the piezoelectric patches fixed box of square box structure, can not only make things convenient for the installation and the location of piezoelectric patches, reduce the assembly degree of difficulty, the top surface of accessible piezoelectric patches fixed box can form common electrode with being connected of each piezoelectric vibrator again, can simplify the structural design of transducer and reduce the assembly degree of difficulty; the ear-shaped structure is arranged on the side wall of the piezoelectric patch fixing box, so that the signal wire can be welded conveniently; the square cavity structure is arranged on the inner side of the transducer shell, so that the piezoelectric sheet fixing box and the piezoelectric sheet can be conveniently installed and positioned.

Drawings

FIG. 1 is a schematic cross-sectional view of a piezoelectric patch in an embodiment;

FIG. 2 is a schematic view of a first segmentation of a piezoelectric sheet in an embodiment;

FIG. 3 is a schematic diagram of a second segmentation of a piezoelectric patch in an embodiment;

FIG. 4 is a schematic view of a third division of a piezoelectric sheet in an embodiment;

FIG. 5 is a schematic view of a fourth division of a piezoelectric sheet in an embodiment;

fig. 6 is a schematic top view of the present invention;

FIG. 7 is a schematic sectional view A-A of FIG. 6;

FIG. 8 is a schematic cross-sectional view B-B of FIG. 7;

fig. 9 is a schematic top view of a transducer housing in accordance with the present invention;

FIG. 10 is a schematic cross-sectional view of C-C of FIG. 9;

FIG. 11 is a schematic cross-sectional view D-D of FIG. 10;

fig. 12 is an exploded schematic view of the present invention;

fig. 13 is a schematic diagram of the welding position of the signal line according to the present invention;

FIG. 14 is an impedance curve real-time graph of a prior art piezoelectric patch having four uniform width piezoelectric vibrators;

fig. 15 is an impedance curve real-time diagram of a piezoelectric sheet having four piezoelectric vibrators with non-uniform widths (inner narrow and outer wide structures) according to the present invention;

fig. 16 is an impedance curve real-time diagram of a piezoelectric sheet having four piezoelectric vibrators with non-uniform widths (inner wide and outer narrow structures) according to the present invention;

in the figure, 1, a piezoelectric patch, 1-1, a piezoelectric vibrator, 1-2, a gap, 1-3, a common connection surface, 2, a piezoelectric patch fixing box, 2-1, a top surface of the piezoelectric patch fixing box, 2-2, an edge of the piezoelectric patch fixing box, 2-3, an ear-shaped structure, 3, a transducer shell, 3-1, a first cylindrical cavity structure, 3-2, a square cavity structure, 3-3, a second cylindrical cavity structure, 3-4, an embedded groove, 4, a matching layer, 5, a first signal line, 6, a second signal line, 7, a backing material layer, 8 and a transducer rear cover.

Detailed Description

The invention will now be further described by way of non-limiting examples with reference to the accompanying drawings:

as shown in fig. 1 to 5, a piezoelectric patch includes a piezoelectric body having a rectangular cross section, the length, width and height of the piezoelectric body are a × b × h, the piezoelectric body is divided into a plurality of strip-shaped piezoelectric vibrators 1-1 having only bottoms connected together to form a common connection surface 1-3 by a plurality of parallel slits 1-2, wherein the width of the piezoelectric vibrator 1-1 located on the inner side is not equal to the width of the piezoelectric vibrator 1-1 located on the outer side, so as to form a non-uniform piezoelectric vibrator array.

Under the condition that the size a x b x h of the piezoelectric sheet and the parameters of the piezoelectric material are fixed, the piezoelectric vibrators 1-1 with different widths have different resonant frequencies, namely, a multi-frequency resonant system is formed, the sizes of the piezoelectric vibrators 1-1 and the width and the depth of a gap 1-2 between the piezoelectric vibrators 1-1 are properly adjusted, and the working bandwidth wider than that of a uniform piezoelectric vibrator array can be obtained under the condition that the working frequency, the sensitivity and other related performances are met. The dimensions a, b and h of the piezoelectric patch 1 may be determined according to the operating frequency, material parameters, electrostatic capacitance, directivity and transducer structure dimensions.

The preferred distribution rule of the piezoelectric vibrators is as follows: the width of the piezoelectric vibrator 1-1 gradually increases from the middle to two sides, namely the inner part is narrow and the outer part is wide, as shown in fig. 2 and 4; or the width of the piezoelectric vibrator 1-1 gradually decreases from the middle to the two sides, i.e., the inside is wide and the outside is narrow, as shown in fig. 3 and 5. Or the width of the piezoelectric vibrator 1-1 may be increased or decreased from the middle to both sides according to a certain gradient, for example, every two piezoelectric vibrators are in a group and have the same width, and then the width is gradually increased or gradually decreased from the middle to both sides according to the way that every two piezoelectric vibrators are in a group.

Further preferably, the piezoelectric vibrators 1-1 are symmetrically distributed around the center line of the piezoelectric body, in this case, the number of the piezoelectric vibrators is even, and the width of the piezoelectric vibrator close to the center line of the piezoelectric body is the largest or the smallest; or the piezoelectric vibrators 1-1 are symmetrically distributed on two sides of the middle piezoelectric vibrator, the number of the piezoelectric vibrators is odd, and the width of the middle piezoelectric vibrator is the maximum or the minimum.

In the present invention, the number of the piezoelectric vibrators 1-1 is preferably 3-8.

In the utility model, preferably, the width of the gap 1-2 between the piezoelectric vibrators is 0.1mm-0.5 mm; the depth of the gap 1-2 between the piezoelectric vibrators is 70% -90% of the thickness of the piezoelectric sheet.

Fig. 14 is a diagram showing an impedance curve of a piezoelectric sheet having four piezoelectric vibrators with uniform width in the prior art. As can be seen from fig. 14, the operating bandwidth BW =46kHz (477 kHz to 523 kHz) of the uniformly distributed piezoelectric sheets with a certain size.

Fig. 15 is an impedance curve real-time diagram of a piezoelectric plate having four piezoelectric vibrators with non-uniform widths (inner narrow and outer wide structures) according to the present invention. As can be seen from fig. 15, the operating bandwidth BW =59kHz (472 kHz to 531 kHz) of the piezoelectric sheets with the same size in the non-uniform distribution is improved by 28.26% compared with the bandwidth of the piezoelectric sheets with the uniform distribution.

Fig. 16 is an impedance curve real-time diagram of a piezoelectric plate having four piezoelectric vibrators with non-uniform widths (inner wide and outer narrow structures) according to the present invention. As can be seen from fig. 16, the operating bandwidth BW =57kHz (469 kHz to 526 kHz) of the piezoelectric sheets with the same size is increased by 23.91% compared with the bandwidth of the piezoelectric sheets with the uniform distribution.

It can be seen that the piezoelectric patches of the present invention have wider operating bandwidths than those of the piezoelectric patches with uniform distribution in the prior art.

As shown in fig. 1 to 16, the present embodiment also provides an ultrasonic transducer for gas flow measurement using the piezoelectric sheet described above. The technical scheme is as follows: an ultrasonic transducer for measuring gas flow comprises a transducer shell 3, and a backing material layer 7, a piezoelectric plate 1 and a matching layer 4 which are sequentially arranged in the transducer shell 3 from bottom to top. The piezoelectric sheet 1 is any one of the piezoelectric sheets described above, and the common joined surface 1-3 of the piezoelectric sheet 1 is located at the lower part and in contact with the backing material layer 7. The backing material layer 7 and the matching layer 4 are both in the prior art, the matching layer 4 is made of composite hard closed-cell materials, and the backing material layer 7 is made of open-cell sound-absorbing materials. A piezoelectric patch fixing box 2 made of metal is further arranged between the matching layer 4 and the piezoelectric patch 1, and the piezoelectric patch fixing box 2 is a rectangular box with a top surface 2-1 and four side walls. In this embodiment, one of the side walls of the piezoelectric patch fixing box 2 is further provided with an ear-shaped structure 2-3, and the lower ends of the four side walls of the box body of the piezoelectric patch fixing box 2 are provided with edges 2-2 protruding outwards. The piezoelectric patch fixing box 2 can be matched with the piezoelectric patch 1 in shape, the piezoelectric patch fixing box 2 covers the piezoelectric patch 1, and the top surfaces 2-1 of the piezoelectric patch fixing box 2 connect the top surfaces of all the piezoelectric vibrators 1-1 in a coplanar manner to form a common electrode. The utility model provides a piezoelectric patches fixed box 2's major structure is convenient for piezoelectric patches 1's installation and location, and piezoelectric patches fixed box 2 also regards as the public electrode of the non-connection face of piezoelectric vibrator array simultaneously. A first signal wire 5 is welded on the common connection surface 1-3 of the piezoelectric patch 1, and a second signal wire 6 is welded on the ear-shaped structure 2-3 of the piezoelectric patch fixing box 2. The outer side of the transducer shell 3 is of a stepped circular truncated cone structure, so that the gas flow channel is convenient to mount and position. For convenience of assembly, in this embodiment, the middle part of the inner side of the transducer housing 3 is a square cavity structure 3-2 capable of being matched with the piezoelectric patch fixing box 2, the upper part of the inner side of the transducer housing 3 is provided with a first cylindrical cavity structure 3-1, the lower part of the inner side of the transducer housing 3 is provided with a second cylindrical cavity structure 3-3, the first cylindrical cavity structure 3-1, the square cavity structure 3-2 and the second cylindrical cavity structure 3-3 are coaxial, wherein the first cylindrical cavity structure 3-1 is used for placing the circular matching layer 4, the square cavity structure 3-2 is matched with the piezoelectric patch fixing box 2, it is ensured that the axis of the piezoelectric patch is coaxial with the axis of the transducer housing, and the second cylindrical cavity structure 3-3 is used for placing the circular backing material layer. The matching layer 4, the piezoelectric sheet 1 and the backing material layer 7 are coaxial. In order to facilitate the installation and the fixation of the piezoelectric patch fixing box 2, in this embodiment, an embedded groove 3-4 capable of being matched with the edge 2-2 of the piezoelectric patch fixing box 2 is arranged on the side wall of the square cavity structure 3-2. The edge 2-2 of the piezoelectric patch fixing box 2 can be clamped into the embedded groove 3-4, so that the piezoelectric patch fixing box 2 is connected with the transducer shell 3.

In order to simplify the assembly process, in the present embodiment, a transducer back cover 8 is further provided, and the transducer back cover 8 is hermetically disposed at the lower end of the transducer housing 3. The transducer rear cover 8 can replace the traditional glue pouring process, so that the assembly process of the transducer is simple and easy to implement.

The utility model discloses an assembly process is:

(1) brushing glue on the opposite surface of the common connection surface 1-3 of the piezoelectric sheet 1; (2) brushing glue on the top surface 2-1 of the piezoelectric patch fixing box 2; (3) sleeving the piezoelectric sheet fixing box 2 on the piezoelectric sheet 1; (4) sleeving the transducer shell 3 on the piezoelectric patch fixing box 2; (5) placing the matching layer 4 within a first cylindrical cavity structure of the transducer housing 3; (6) welding a first signal wire 5 on the common connection surface 1-3 of the piezoelectric sheet 1 and welding a second signal wire 6 on the ear-shaped structure 2-3; (7) a backing material layer 7 is arranged on the common connection surface 1-3 of the piezoelectric sheet 1; (8) gluing the transducer housing 3 on the periphery of the backing material layer; (9) mounting the transducer back cover 8; (10) and fixing the transducer, pressurizing along the height direction, and releasing the pressure after the colloid is solidified to obtain a finished product of the molding transducer.

Other parts in this embodiment are the prior art, and are not described herein again.

Claims (10)

1. A piezoelectric piece comprises a piezoelectric body with a rectangular section, and is characterized in that the piezoelectric body is divided into a plurality of strip-shaped piezoelectric vibrators only the bottoms of which are connected together to form a common connection surface by a plurality of parallel gaps, and the width of the piezoelectric vibrator positioned on the inner side is not equal to that of the piezoelectric vibrator positioned on the outer side.

2. A piezoelectric patch as claimed in claim 1, wherein: the width of the piezoelectric vibrator is gradually increased or decreased from the middle to two sides; or the width of the piezoelectric vibrator is increased or decreased from the middle to two sides according to a certain gradient.

3. A piezoelectric patch as claimed in claim 2, wherein: the piezoelectric vibrators are symmetrically distributed on the central line of the piezoelectric body or on two sides of the piezoelectric vibrator in the middle.

4. A piezoelectric patch as claimed in claim 1, wherein: the number of the piezoelectric vibrators is 3-8.

5. A piezoelectric patch as claimed in claim 1 or claim 2 or claim 3 or claim 4, wherein: the width of the gap between the piezoelectric vibrators is 0.1mm-0.5 mm; the depth of the gap between the piezoelectric vibrators is 70-90% of the thickness of the piezoelectric sheet.

6. The utility model provides an ultrasonic transducer for gas flow measurement, includes transducer casing (3), sets gradually backing material layer (7), piezoelectric patches (1), matching layer (4) in transducer casing (3) from bottom to top, characterized by: the piezoelectric patch (1) is the piezoelectric patch according to any one of claims 1 to 5, a common connection surface of the piezoelectric patch (1) is located at the lower part and is in contact with the backing material layer (7), a piezoelectric patch fixing box (2) made of a metal material is further arranged between the matching layer (4) and the piezoelectric patch (1), the piezoelectric patch fixing box (2) is a rectangular box with a top surface and matched with the piezoelectric patch (1), the piezoelectric patch fixing box (2) is covered on the piezoelectric patch (1), the top surface of the piezoelectric patch fixing box (2) connects the top surfaces of the piezoelectric vibrators (1-1) to form a common electrode, a first signal line (5) is connected to the common connection surface of the piezoelectric patch (1), and a second signal line (6) is connected to the piezoelectric patch fixing box (2).

7. The ultrasonic transducer for gas flow measurement of claim 6, wherein: the side wall of the piezoelectric patch fixing box (2) is provided with an ear-shaped structure (2-3), and the second signal line (6) is connected with the ear-shaped structure (2-3).

8. The ultrasonic transducer for gas flow measurement according to claim 6 or 7, wherein: the piezoelectric patch fixing device is characterized in that the lower end of the piezoelectric patch fixing box (2) is provided with an edge protruding outwards, the middle part of the inner side of the transducer shell (3) is a square cavity structure (3-2) matched with the piezoelectric patch fixing box (2), and an embedded groove (3-4) matched with the edge of the piezoelectric patch fixing box (2) is formed in the side wall of the square cavity structure (3-2).

9. The ultrasonic transducer for gas flow measurement of claim 8, wherein: and the upper part and the lower part of the inner side of the energy converter shell (3) are respectively provided with a cylindrical cavity structure which is coaxial with the square cavity structure (3-2).

10. The ultrasonic transducer for gas flow measurement according to claim 6 or 7, wherein: the energy converter is further provided with a rear energy converter cover (8), and the rear energy converter cover (8) is arranged at the lower end of the energy converter shell (3) in a sealing mode.

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