CN104646263A - Conical hole front cover plate broadband longitudinal vibration transducer - Google Patents

Abstract

A conical hole front cover plate broadband longitudinal vibration transducer comprises a front cover plate and a rear cover plate. A piezoelectric crystal is mounted between the front cover plate and the rear cover plate, a conical hole is dug in the front cover plate, and the depth of the conical hole is smaller than the thickness of the front cover plate. The front cover plate comprises a first cone frustum portion and a second cone frustum portion with the conical hole. A portion is dug out from the front cover plate to form the conical hole, the proper size of the hole is selected, and the frequency bandwidth of the transducer with the conical hole front cover plate is about doubled as compared with that of a transducer with a front cover plate as a solid cone frustum.

Description

Cone hole front shroud broadband extensional vibration transducer

Technical field

The present invention relates to a kind of transducer, particularly a kind of cone hole front shroud broadband extensional vibration transducer.

Background technology

Compound bar extensional vibration transducer is a kind of conventional high power transmitter, and it has that structure is simple, handling ease, efficiency are high and the advantage such as power is large, is widely used in underwater acoustic technology.Broadband technology is the important trend developed in underwater sound field, in order to expand the bandwidth of compound bar extensional vibration transducer, recent domestic scholar has carried out much research, propose several method widening transducer bandwidth: 1), utilize the coupling between the flexural vibrations of front shroud and the extensional vibration of transducer to expand the bandwidth of transducer, the method needs frequency interval and the amplitude size of control two kinds of mode; 2), adopt double excitation source to expand the bandwidth of transducer, this method expands the bandwidth of transducer, because restriction the method for the physical dimension of transducer has certain difficulty on the implementation by the resonant frequency that two driving sources produce; 3), add at the previous irradiation head of transducer the transmission characteristic that appropriate characteristics impedance matching layer also can improve transducer.This technology obtains application in transducer array.

Summary of the invention

The object of this invention is to provide a kind of cone hole front shroud broadband extensional vibration transducer, cone hole front shroud is formed to the process of digging a hole of transducer front shroud, chooses the size in suitable hole, effectively can widen the frequency bandwidth of transducer.

The technical scheme that the present invention takes is: cone hole front shroud broadband extensional vibration transducer, comprise front shroud, back shroud, be provided with piezo-electric crystal between described front shroud and back shroud, described front shroud has dug a conical cone hole, and the degree of depth in described cone hole is less than the thickness of front shroud.Described front shroud comprises: the first round platform part and the second round platform part with cone hole.

The basal diameter in described cone hole is 0.8 times of front shroud basal diameter, and the degree of depth in described cone hole is 0.5 times of front shroud thickness.

Described back shroud is fluted body.

Described front shroud is that aluminum material is made, and described back shroud is that copper material is made, and described piezo-electric crystal is PZT-4 material.

The present invention's one cone hole front shroud broadband extensional vibration transducer, utilize on front shroud, dig up part formation cone hole, select the size in suitable hole, about being with the frequency bandwidth of the transducer of cone hole front shroud to improve twice than the transducer that front shroud is solid round platform.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described:

Fig. 1 is transducer architecture schematic diagram of the present invention;

Fig. 2 is transducer front shroud cross-sectional view of the present invention;

Fig. 3 is equivalent circuit of transducer figure of the present invention;

Fig. 4 is the transducer architecture schematic diagram of fluted body back shroud of the present invention.

Detailed description of the invention

As Figure 1 and Figure 4, cone hole front shroud broadband extensional vibration transducer, comprises front shroud 3, back shroud 1, is provided with piezo-electric crystal 2 between described front shroud 3 and back shroud 1, described front shroud 3 has dug a conical cone hole 6, and the degree of depth h1 in described cone hole 6 is less than the thickness h 0 of front shroud 3.Described front shroud 3 comprises: the first round platform part 4 and the second round platform part 5 with cone hole 6.Described back shroud 1 is fluted body.

The basal diameter D1 in described cone hole 6 is 0.8 times of front shroud 3 basal diameter D0.The degree of depth h1 in described cone hole 6 is 0.5 times of front shroud 3 thickness h 0.

Described front shroud 3 is made for aluminum material, and described back shroud 1 is made for copper material, and described piezo-electric crystal 2 is PZT-4 material.

Theory analysis:

Structural representation of the present invention is as shown in Figure 1: in Fig. 1, A-B is transducer nodel line position.

According to the theory analysis to extensional vibration transducer in " underwater acoustic transducer and basic matrix " book, the equivalent circuit of extensional vibration transducer as shown in Figure 3.In Fig. 3:

$Z_{b1}=j{\mathrm{\ρ}}_1{c}_1{s}_1\mathrm{tg}\left(\frac{k_1{l}_b}{2}\right);Z_{b2}=\frac{{\mathrm{\ρ}}_1{c}_1{s}_1}{j\sin \left(k_1{l}_b\right)};$

$Z_{c2}=j{\mathrm{\ρ}}_0{\mathrm{cs}}_1\mathrm{tg}\left(\frac{\mathrm{nkl}}{2}\right);Z_{c2}=\frac{{\mathrm{\ρ}}_0\mathrm{cs}}{j\sin \left(\mathrm{nkl}\right)}.$

ρ in formula ₁, c ₁, k ₁, l _band s ₁be respectively the density of cylindrical metal, the velocity of sound, wave number, length and cross-sectional area; Zf ₁, Zf ₂, Zf ₃₁for front shroud equiva lent impedance, Z _r1, Z _r2be respectively the load impedance of front shroud and back shroud and liquid medium touching position.

Front shroud theory analysis:

Front shroud 3 is divided into two parts, the first round platform part 4 and the second round platform part 5 with cone hole 6.

The vibration equation of general bar of variable cross-section is:

$\frac{{\∂}^2\mathrm{\ξ}}{{\∂x}^2}+\frac{1}{S\left(x\right)}\frac{\∂S\left(x\right)}{\∂x}\frac{\∂\mathrm{\ξ}}{\∂x}+k^2\mathrm{\ξ}=0$

For simple harmonic oscillation:

ξ=ξ(x)e ^jωt

For the first round platform part 4, order:

$D=\frac{r_3}{a},S_4\left(x_4\right)={\mathrm{\πr}}_4^2\left(x_4\right)$

r ₄(x ₄)=r ₃+Dx ₄，S ₄(x ₄)=π(r ₃+Dx ₄) ²

Vibration equation can be written as

$\frac{{\∂}^2\mathrm{\ξ}}{{\∂x}_4^2}+\frac{2D}{{\mathrm{Dx}}_4+r_2}\frac{\∂\mathrm{\ξ}}{{\∂x}_4}+k^2\mathrm{\ξ}=0$

Cause

$u=\frac{\∂\mathrm{\ξ}}{\∂t}=\mathrm{j\ω\ξ}$

Then can obtain

$u_4\left(x_4\right)=\frac{A_4}{x_4+a}\cos [k_4(x_4+a)+{\mathrm{\δ}}_4]$

$F_4\left(x_4\right)=\frac{j{\mathrm{\ρ}}_4{c}_{4}S\left(x_4\right)}{x_4+a}{A}_4\left\{\sin \right[k_4(x_4+a)+{\mathrm{\δ}}_4]+\frac{1}{k_4(x_4+a)}\cos [k_4(x_4+a)+{\mathrm{\δ}}_4\left]\right\}$

A in formula ₄, δ ₄for undetermined constant.

For the second round platform part 5:

If arbitrary section radius of round platform is r ₆x (), arbitrary section radius of circular cone is r ₅(x).Then have

$S_5\left(x\right)=\mathrm{\π}[r_6^2\left(x\right)-r_5^2\left(x\right)]$

If

θ ₁=θ ₂，r ₆(x)=(a+l ₄+x)tanθ ₁，r ₅(x)=xtanθ ₂

Like this

$S_5\left(x\right)=\mathrm{\π}[{(a+l_4)}^2+2(a+l_4)x]\frac{r_4^2}{{(a+l_4)}^2}$

So have:

$\frac{{\∂}^{2}u}{{\∂x}^2}+\frac{2}{2x+a+l_4}\frac{\∂u}{\∂x}+k_4^{2}u=0$

Make replacement y=2x, then above formula becomes:

$\frac{{\∂}^{2}u}{{\∂y}^2}+\frac{2}{y+a+l_4}\frac{\∂u}{\∂y}+{2k}_4^{2}u=0$

Its general solution is:

$u_5\left(x_5\right)=\frac{A_5}{{2x}_5+a+l_4}\cos [k_5({2x}_5+a+l_4)+{\mathrm{\δ}}_5]$

$F_5\left(x_5\right)=\frac{j{\mathrm{\ρ}}_4{c}_4{S}_5\left(x_5\right)}{{2x}_5+a+l_4}{A}_5\left\{\sin \right[k_5({2x}_5+a+l_4)+{\mathrm{\δ}}_5]+\frac{\cos [k_5({2x}_5+a+l_4)+{\mathrm{\δ}}_5]}{k_5({2x}_5+a+l_4)}\}$

A in formula ₅, δ ₅for undetermined coefficient, can in the hope of A by boundary condition ₄, δ ₄, A ₅, δ ₅, u ₄(x ₄), F ₄(x ₄) be respectively x=x ₄the vibration velocity in face and stressed, u ₅(x ₅), F ₅(x ₅) be then x=x ₅the vibration velocity in face and stressed, obtains u ₄, F ₄, u ₅, F ₅network theory just can be utilized afterwards to draw the isoboles of front shroud, analyze its performance further.

Design and produce longitudinal transducer that resonant frequency in water is 8kHz, back shroud 1 is designed to groove-like: namely barrel-shaped.Can effectively reduce transducer longitudinal size, its structure as shown in Figure 4.Open cone hole 6 to front shroud 3 to process, the basal diameter D1 in described cone hole 6 is 0.8 times of front shroud 3 basal diameter D0.The degree of depth h1 in described cone hole 6 is 0.5 times of front shroud 3 thickness h 0.

The main performance of two kinds of transducers:

The transducer of common front shroud:

(a), resonant frequency 8kHz;

B (), resonance point voltage discharge respond: 142dB;

(c), bandwidth: 2.8kHz.

Punch the transducer of front shroud:

(a), resonant frequency 8kHz;

B (), resonance point voltage discharge respond: 140dB;

(c), bandwidth: 5.4kHz.

Claims (8)

1. bore hole front shroud broadband extensional vibration transducer, comprise front shroud (3), back shroud (1), piezo-electric crystal (2) is installed between described front shroud (3) and back shroud (1), it is characterized in that, described front shroud (3) has dug a conical cone hole (6), and the degree of depth of described cone hole (6) is less than the thickness of front shroud.

2. bore hole front shroud broadband extensional vibration transducer according to claim 1, it is characterized in that, described front shroud (3) comprising: the first round platform part (4) and the second round platform part (5) with cone hole (6).

3. bore hole front shroud broadband extensional vibration transducer according to claim 1, it is characterized in that, 0.8 times that the basal diameter (D1) of described cone hole (6) is front shroud (3) basal diameter (D0).

4. bore hole front shroud broadband extensional vibration transducer according to claim 1, it is characterized in that, 0.5 times that the degree of depth (h1) of described cone hole (6) is front shroud (3) thickness (h0).

5. bore hole front shroud broadband extensional vibration transducer according to claim 1, it is characterized in that, described back shroud (1) is fluted body.

6. according to claim 1 or 2, bore hole front shroud broadband extensional vibration transducer, it is characterized in that, described front shroud (3) is made for aluminum material.

7. according to claim 1 or 5, bore hole front shroud broadband extensional vibration transducer, it is characterized in that, described back shroud (1) is made for copper material.

8. bore hole front shroud broadband extensional vibration transducer according to claim 1, it is characterized in that, described piezo-electric crystal (2) is PZT-4 material.