CN103843366A

CN103843366A - Ultrasonic sensor and manufacturing method therefor

Info

Publication number: CN103843366A
Application number: CN201280048808.6A
Authority: CN
Inventors: 矶元真弓
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2011-10-04
Filing date: 2012-10-02
Publication date: 2014-06-04
Anticipated expiration: 2032-10-02
Also published as: KR101491509B1; KR20140053405A; JPWO2013051524A1; CN103843366B; WO2013051524A1; JP5522311B2

Abstract

An ultrasonic sensor (101) is provided with: a bottomed cylindrical case (31) having a bottom section (31b) and side wall section (31a); a piezoelectric element (32) disposed inside the bottom of the case (31); terminals (43), which are electrically connected to the piezoelectric element (32) via a conductive member inside the case (31), and protrude to the outside of the case (31); a terminal holding member (41) which holds the terminals (43); a buffer member (33) which holds the terminal holding member (41) inside the case (31); a damping member (39) which is disposed along the inner peripheral surface of the side wall section (31a) of the case (31); and a filler member (36) which is filled in above the damping member (39) and the buffer member (33), inside the case (31). A gap (40) is disposed between the damping member (39) and the buffer member (33). This configuration prevents vibration leakages to the terminals, improving reverberation characteristics resulting from vibration leakages.

Description

Ultrasonic sensor and manufacture method thereof

Technical field

The present invention relates to ultrasonic sensor and manufacture method thereof, especially relate to the input and output terminal, for example ultrasonic sensor and the manufacture method thereof of use in turning sonar, the reversing sonar etc. of motor vehicle that there is piezoelectric element and be electrically connected with this piezoelectric element.

Background technology

Ultrasonic sensor is the device that detects object by indirectly sending ultrasonic pulse signal and being received in the reflected signal reflecting after the ultrasonic pulse signal arrival object sending out.At the reversing sonar of motor vehicle, turning sonar and then while detecting parallel parking and in the parking spot sensor of the distance of the barrier such as sidewall, adopt ultrasonic sensor.This ultrasonic sensor has open in patent documentation 1～3.

Fig. 9 is the partial cutoff front view of the ultrasonic sensor of patent documentation 1.This ultrasonic sensor possesses ultrasonic oscillator 1, buffer component 2, shielding conductor 5, sound-absorbing part 6 and housing 3.Buffer component 2 have ultrasonic wave send receive use opening and around ultrasonic oscillator 1.Housing 3 is molded part, and ultrasonic oscillator 1 and buffer component 2 are received.One end of shielding conductor 5 is connected with ultrasonic oscillator 1 in the inside of housing 3, and draw to outside from housing 3 the other end.And, in the inside of buffer component 2 and the part corresponding with the side of ultrasonic oscillator 1, be formed with air layer 4 to surround the mode of ultrasonic oscillator 1.

In patent documentation 2, disclose the structure of ultrasonic sensor as described below, that is, this ultrasonic sensor possesses: ultrasonic oscillator; There is the bottom surface sections that is stained with ultrasonic oscillator and forms ultrasonic wave radiation wall and the interior side box body of cylindrical sidewall; There is the outer side box body that is the cylindrical sidewall of coaxial shape configuration with the cylindrical sidewall of interior side box body, outer side box body supports at the internal side box body of multiple supporting portions of ultrasonic wave radiation wall side, beyond multiple supporting portions, locate, between the outer wall of cylindrical sidewall of interior side box body and the outer wall of the cylindrical sidewall of outer side box body, be formed with gap.

In patent documentation 3, disclose the structure of ultrasonic sensor as described below, that is, this ultrasonic sensor possesses: ultrasonic oscillator; There is ultrasonic wave and send the opening that receives use and the retaining member that surrounds ultrasonic oscillator; For molded part and to the housing that ultrasonic oscillator and retaining member are received, be provided with protuberance by the inner side at retaining member, thus the generation gap, position beyond protuberance.

Formerly technical literature

Patent documentation

Patent documentation 1: 4-No. 238497 communiques of Japanese kokai publication hei

Patent documentation 2: 2003-No. 315443 communiques of TOHKEMY

Patent documentation 3: 5-No. 207594 communiques of Japanese kokai publication hei

Summary of the invention

Invent problem to be solved

In the existing ultrasonic sensor shown in patent documentation 1～3, under the effect in above-mentioned air layer and gap, the vibration of ultrasonic oscillator is difficult to transmit to shell (housing, casing).Therefore, there is the shortening effect of reverberation time.

But, in the case of carry out the signal of telecommunication input and output member not for lead-in wire (or shielding conductor) be made as pin terminal, the vibration of shell is propagated to pin terminal, producing this vibration makes the problem of the external circuit substrate vibration that ultrasonic sensor is installed (be called below, " vibration is leaked ".)。Because this vibration leakage makes the reverberation time elongated (reverberation characteristic deterioration).And, if the reverberation time spin out, in the time that detection is positioned at in-plant object, owing to receiving reflected signal within the duration of the reverberation of the ultrasonic pulse signal based on sending out, therefore cannot realize the detection that is positioned at in-plant object.

The object of the invention is to, provide a kind of preventing to leak, improve to the vibration of terminal the ultrasonic sensor that is leaked the reverberation characteristic causing by vibration.

For solving the mode of problem

(1) ultrasonic sensor of the present invention is characterised in that to possess:

Have the shell of bottom tube-like, it has bottom and side wall portion;

Piezoelectric element, it is located at the inner bottom surface of described shell;

Terminal, it is electrically connected with described piezoelectric element via conducting member in described shell, and outstanding to the outside of described shell;

Terminal retaining member, it keeps described terminal;

Buffer component, it keeps described terminal retaining member in described shell;

Damping member, it is along the inner peripheral surface setting of the side wall portion of described shell;

Noggin piece, it is filled in the top of damping member in described shell, described and described buffer component,

Between described damping member and described buffer component, be provided with gap (air layer).

According to this structure, the damped member of vibration, buffer component and gap (air layer) decay (blocking) that come from shell transmission, almost cannot propagate to terminal by terminal retaining member, therefore, can reduce significantly the vibration producing when terminal is installed on to outside circuit substrate leaks.

(2) preferably, described in the modular ratio of described noggin piece, damping member is little.According to this structure, can reduce the vibration of directly transmitting to terminal from the little noggin piece of modular ratio damping member and leak.In addition, damping member becomes not the structure of directly joining with terminal, and the modulus of elasticity of damping member is difficult to impact vibration leakage characteristics, therefore the range of choice of damping member broadens.

(3) interface (peristome of air layer) preferably, also possessing described gap and described noggin piece is carried out inaccessible obstruction component (inserting mortar resin).According to this structure, can make simplifying the structure of buffer component.

(4) preferably, the side wall portion of described shell possesses thinner wall section and possesses heavy section at bottom side in open side,

On heavy section, be provided with the reinforcement that acoustic impedance is higher than shell.According to this structure, the rigidity of the surrounding of the bottom surface of shell uprises, and the vibration of shell bottom surface is suppressed to the propagation of side wall of outer shell portion, and is improved as the sensitivity of transducer.

(5) preferably, between described piezoelectric element and described buffer component, be provided with Sound-absorbing member.According to this structure, utilize sound-absorbing part to absorb useless sound wave, efficiency makes the useless SATT from piezoelectric element to shell internal delivery well more.

(6) manufacture method of ultrasonic sensor of the present invention is the manufacture method of the ultrasonic sensor of (1)～(5) either side, it is characterized in that, comprising:

By external diameter than the large circular shaping mould of described buffer component to the operation of inserting in described shell;

The operation that the elastic resin that described damping member is formed to use is filled to the surrounding of the described shaping mould in described shell;

Described shaping mould is removed and is carried the operation of described buffer component in described shell from described shell.

Invention effect

According to the present invention, the damped member of vibration, buffer component and gap (air layer) decay (blocking) that come from shell transmission, can not propagate to terminal by terminal retaining member substantially, therefore, can reduce significantly vibration and leak.Therefore, can prevent from being leaked by vibration the deterioration of the reverberation characteristic causing, thereby can realize the detection that is positioned at more in-plant object.

Accompanying drawing explanation

Fig. 1 is the cutaway view of the related ultrasonic sensor of the first execution mode 101.

Fig. 2 is the exploded perspective view of the removal part of ultrasonic sensor 101.

Fig. 3 in Fig. 3 (A) is the figure that represents the reverberation characteristic of the related ultrasonic sensor of the first execution mode 101, and Fig. 3 (B) is the figure that represents the reverberation characteristic of ultrasonic sensor as a comparative example.

Fig. 4 is the figure that represents the gap 40 between damping member 39 and buffer component 33 and vibrate the relation of leak time.

Fig. 5 is the figure that represents the operation that forms damping member 39 and gap 40.

Fig. 6 is the cutaway view of the related ultrasonic sensor of the second execution mode 102.

Fig. 7 is the cutaway view of the related ultrasonic sensor 103 of the 3rd execution mode.

Fig. 8 is the cutaway view of the related ultrasonic sensor 104 of the 4th execution mode.

Fig. 9 is the partial cutoff front view of the ultrasonic sensor of patent documentation 1.

Embodiment

" the first execution mode "

Fig. 1 is the cutaway view of the related ultrasonic sensor of the first execution mode 101.Fig. 2 is the exploded perspective view of the removal part of ultrasonic sensor 101.

Ultrasonic sensor 101 comprises: have the shell that has bottom tube-like 31 of the aluminum of the side wall portion 31a of discoideus bottom 31b and tubular, the piezoelectric element 32 that is attached at the inner bottom surface of shell 31, reinforcement (spindle) 37, terminal 43, keep the terminal retaining member 41 of terminal 43 etc.Terminal 43 is electrically connected by the unshowned distribution part of Fig. 1 (conducting member) with piezoelectric element 32.Distribution part (conducting member) is for example lead-in wire, flexible base, board etc.Piezoelectric element 32 is tabular, in the time being applied in driving voltage along Directional Extension vibration in face.Piezoelectric element 32 engages with the bottom 31b of shell 31.Piezoelectric element 32 is for example made up of piezoelectric ceramic, has the piezoelectric substrate of circular plate shape and is located at respectively the electrode on the mutual opposed interarea of piezoelectric substrate.

As shown in Figure 2, the opposition side opening that shell 31 is bottom 31b side obturation, bottom 31b side have a bottom tube-like, the opening of shell 31 overlook under observation rounded.The side wall portion 31a of shell 31 possesses thinner wall section 31t and has heavy section 31h at bottom side in open side.Side wall portion 31a at shell 31 is formed with stage portion 31ST.

Reinforcement (spindle) 37 is for having the annular component of opening 37h in central authorities, be configured in the heavy section 31h of shell 31 upper and be configured in the position not joining with the inner peripheral surface of the thinner wall section 31t of side wall portion 31a.Reinforcement 37 is for acoustic impedance is compared with the high member as spindle performance function.Therefore, reinforcement 37 can be the member by the material identical with shell 31, being made up of aluminium by adjusting thickness equidimension, but is preferably made up of the material high and that rigidity is high of the material phase specific density with forming shell 31 as stainless steel, zinc.

As shown in Figure 2, in the 31b of bottom by stage portion 31ST around region be main vibration area.The main vibration area of shell 31 is rectangle overlooking under observation, and y direction of principal axis is long therefore y direction of principal axis is major axis, and x direction of principal axis is short therefore x direction of principal axis is minor axis.Like this, main vibration area has anisotropic shape, therefore hyperacoustic directive property produces anisotropy.That is, the sensing angle of described long axis direction (y direction of principal axis) is narrow, the sensing angular width of described short-axis direction (x direction of principal axis).

On piezoelectric element 32, be provided with flat sound-absorbing part 38.Sound-absorbing part 38 be configured in shell 31 inside by stage portion 31ST around space in.Sound-absorbing part 38 is made up of such as polyester felt, Porous silicone etc., and the useless ultrasonic wave that the open side from piezoelectric element 32 to shell 31 is discharged absorbs.Between reinforcement 37 and sound-absorbing part 38 and terminal retaining member 41, be provided with the buffer component 33 being formed by the elastomer such as silicone rubber, polyurethane rubber.Buffer component 33 is at the interior maintenance terminal of shell 31 retaining member 41.Be provided with along the inner peripheral surface of the side wall portion 31a of shell 31 by the elastomer such as polyurethane rubber, silicone rubber and form and as the damping member 39 in central authorities with the cylindrical member of opening.And, between damping member 39 and buffer component 33, be formed with gap (air layer) 40.Particularly, buffer component 33 has the part of flange shape (the chimb shape) that contact with damping member 39, forms gap (air layer) 40 by the part of this flange shape (chimb shape) between damping member 39 and buffer component 33.

In the inside of shell 31, in the space on the top of damping member 39 and buffer component 33, be filled with the noggin piece 36 being formed by the elastomer such as silicone rubber, polyurethane rubber.Noggin piece 36 and damping member 39 can adopt identical material.

Shell 31 can form by for example forging.The member that bolster 33 is cup-shaped, comprises and has the bottom of holding section 33e and the side wall portion of tubular that engage with the opening 37h of reinforcement 37.By bolster 33 is set, can suppress the situation that the vibration in the bottom 31b of shell 31 is transmitted to terminal keeper 41.

Terminal retaining member 41 is made up of resins such as polybutylene terephthalate (PBT)s (PBT), and two pin-shaped terminals 43 are kept.Terminal retaining member 41 have the flange shape holding section that engages with the inner surface of the side wall portion of the tubular of buffer component 33 (following, be called " flange part ".)41f。The upper surface 41s of the flange part 41f of terminal retaining member 41 is covered by noggin piece 36.

So, owing to being provided with the damping member 39 joining with the inner peripheral surface of the side wall portion 31a of shell 31, therefore the damped member 39 of the vibration of the side wall portion 31a of shell 31 is decayed.And by be formed with gap (air layer) 40 between damping member 39 and buffer component 33, the vibration of the side wall portion 31a of shell 31 is difficult to propagate to buffer component 33 via damping member 39., can, according to the propagated vibration of buffer component 33 → terminal retaining member 41 → terminal 43, can effectively press down the moving leakage of vibration damping hardly.In addition, the vibration of propagating from shell 31 via the part beyond gap (air layer) 40 decays among noggin piece 36, propagates hardly via terminal retaining member 41 to terminal 43.

According to above-mentioned effect, can significantly reduce the vibration producing when ultrasonic sensor 101 is installed on to outside circuit substrate and leak.

In addition, the upper surface 41s of the flange part 41f by terminal retaining member 41 is covered by noggin piece 36, can prevent the situation that terminal retaining member 41 departs from from shell 31.

Buffer component 33 is the structures that are difficult to propagate vibration, and damping member 39 and noggin piece 36 are the structures that suppress the vibration of the side wall portion 31a of (vibration damping) shell 31.Be damping member 39 and noggin piece 36 preferred elastomeric modular ratio buffer component 33 height.More specifically, modulus of elasticity comprises energy storage modulus of elasticity and loss elastic modulus, and preferably the loss elastic modulus of damping member 39 and noggin piece 36 is large and the energy storage modulus of elasticity of buffer component 33 is little.

Fig. 3 (A) is the figure that represents the reverberation characteristic of the related ultrasonic sensor of the first execution mode 101, and Fig. 3 (B) is the figure that represents the reverberation characteristic of ultrasonic sensor as a comparative example.The ultrasonic sensor of this comparative example does not have the gap 40 shown in Fig. 1, and in this part, expansion has buffer component 33, except not having gap 40 these one side, is the ultrasonic sensor 101 identical structure related with the first execution mode.In Fig. 3 (A) and Fig. 3 (B), represent transverse axis 500, represent the longitudinal axis by 1V/div by μ s/div.In addition, be all to utilize soldering that terminal 43 is fixed on outside circuit substrate, the pulse train ripple that sends eight ripples according to transmitting time 0.13ms, amplifies to observe to the voltage waveform manifesting in piezoelectric element.Although reality is the decay of beginning amplitude from transmission has just finished, owing to temporarily exceeding the dynamic range of amplifying circuit, therefore the waveform of its time is saturated.

From Fig. 3 (A) and Fig. 3 (B) contrast can be known and be obtained, in the related ultrasonic sensor 101 of the first execution mode, amplitude is convergence early, vibration leak be inhibited and the reverberation time short.

Fig. 4 is the figure that represents the gap 40 between damping member 39 and buffer component 33 and vibrate the relation of leak time.At this, " vibration leak time " is as terminal 43 being utilized soldering be fixed on the common reverberation time under the state on outside circuit substrate and utilizing the vibration that the clampings such as silicone rubber are leaked to terminal 43 to suppress to vibrate the time that the variation reverberation time, reverberation under the state leaking defines.The deviation of vibrating leak time in the situation that of in the situation that gap 40 is not set, at comparative example is larger, and by gap 40 is set, vibration leak time becomes very little, and deviation also diminishes.Known according to its result, by being provided with the gap that exceedes 0mm, vibration leak time be suppressed to as the grade that can use, be less than 0.1ms.

It should be noted that, according to the first execution mode, because the peristome of shell 31 is airtight by terminal retaining member 41 and noggin piece 36, therefore, in the inside of shell 31, do not have water to be immersed in the problem that inside causes sensitivity or generation is corroded between dissimilar metal.

About illustrate above for describing with reference to figure 5 in the interior manufacture method that gap 40 is set of ultrasonic sensor 101.

Fig. 5 is the figure that represents the operation that forms damping member 39 and gap 40.First, as shown in Fig. 5 (A), at the interior joint piezoelectric element 32 of shell 31, reinforcement 37 is installed, Sound-absorbing member 38 is configured on piezoelectric element 32, be assembled into pattern 51.Shaping mould 51 to exist the mode having with the gap of damping member 39 same shapes to configure between the side wall portion 31a of itself and shell 31.Then,, as shown in Fig. 5 (B), inserting mortar resin 39P be coated in the part in the gap between the side wall portion 31a of shaping mould 51 and shell 31 and make it sclerosis.Inserting mortar resin 39P is made up of the material identical with damping member 39, becomes afterwards a part for damping member 39.Then, as shown in Fig. 5 (C), in the gap by resin-coated (filling) of damping member 39 use between the side wall portion 31a of shaping mould 51 and shell 31 and make it sclerosis.Afterwards, as shown in Fig. 5 (D), remove shaping mould 51, as Fig. 5 (E), assemble buffer component 33.

According to above operation, between damping member 39 and buffer component 33, be provided with gap 40.

" the second execution mode "

Fig. 6 is the cutaway view of the related ultrasonic sensor of the second execution mode 102.The structure of ultrasonic sensor 102 is identical with the ultrasonic sensor 101 shown in the first execution mode.But, noggin piece 36 is made up of the material different from damping member 39.In the ultrasonic sensor 102 of the second execution mode, the modulus of elasticity of the modular ratio damping member 39 of noggin piece 36 is little.

For example damping member 39 is made up of polyurethane rubber, and noggin piece 36 is made up of silicone rubber.In addition, as long as make the modulus of elasticity of noggin piece 36 different from the modulus of elasticity of damping member 39, both also can be polyurethane rubber.Damping member 39 is the high elastic component of side wall portion 31a vibration damping with respect to shell 31, the elastic component of noggin piece 36 for being difficult to the vibration of side wall portion 31a to be propagated to terminal retaining member 41.

" the 3rd execution mode "

Fig. 7 is the cutaway view of the related ultrasonic sensor 103 of the 3rd execution mode.In ultrasonic sensor 103, possess gap 40 and the interface of noggin piece 36 are carried out to inaccessible obstruction component 34.Other structure is identical with the ultrasonic sensor 101 shown in the first execution mode.

Obstruction component 34 can be by utilizing distributor coating thixotropy to arrange up to the resin that can not be immersed in the degree in gap 40.

So, by utilizing obstruction component 34 to carry out obturation (inserting mortar) to gap 40 and the interface (peristome of air layer) of noggin piece 36, prevented the inflow to gap 40 of potting resin in the time of the filling of noggin piece 36.

In addition, by employing obstruction component 34 like this, without the part that forms flange shape (the chimb shape) that contact with damping member 39 at buffer component 33, therefore, can make the simple shape of buffer component 33.

" the 4th execution mode "

Fig. 8 is the cutaway view of the related ultrasonic sensor 104 of the 4th execution mode.In ultrasonic sensor 104, utilize noggin piece 36 to carry out obturation to the opening in the gap 40 between damping member 39 and buffer component 33.Other structure is identical with the ultrasonic sensor 101 shown in the first execution mode.

In noggin piece 36, adopt thixotropy can not flow into the resin material of the degree in gap 40 up to resin in the time that it is filled.

Reference numeral explanation

31 ... shell

31a ... side wall portion

31b ... bottom

31h ... heavy section

31ST ... stage portion

31t ... thinner wall section

32 ... piezoelectric element

33 ... buffer component

33e ... holding section

34 ... obstruction component

36 ... noggin piece

37 ... reinforcement

37h ... opening

38 ... Sound-absorbing member

39 ... damping member

40 ... gap

41 ... terminal retaining member

41f ... flange part

41s ... upper surface

43 ... terminal

51 ... shaping mould

101～104 ... ultrasonic sensor

Claims

1. a ultrasonic sensor, is characterized in that, possesses:

Have the shell of bottom tube-like, it has bottom and side wall portion;

Terminal retaining member, it keeps described terminal;

Between described damping member and described buffer component, be provided with gap.

2. ultrasonic sensor as claimed in claim 1, is characterized in that,

Described in the modular ratio of described noggin piece, damping member is little.

3. ultrasonic sensor as claimed in claim 1 or 2, is characterized in that,

Also possess obstruction component, it carries out obturation to the interface of described gap and described noggin piece.

4. the ultrasonic sensor as described in any one in claim 1～3, is characterized in that,

The side wall portion of described shell possesses thinner wall section and possesses heavy section at described bottom side in open side,

On described heavy section, be provided with the reinforcement that acoustic impedance is higher than described shell.

5. the ultrasonic sensor as described in any one in claim 1～4, is characterized in that,

Between described piezoelectric element and described buffer component, be provided with Sound-absorbing member.

6. a manufacture method for ultrasonic sensor, the method is the manufacture method of the ultrasonic sensor described in any one in claim 1～5, it is characterized in that, comprising:

The elastic resin of described damping member formation use is filled in to the operation of the surrounding of the described shaping mould in described shell;