JP3213818B2 - Ultrasonic sensor - Google Patents
Ultrasonic sensorInfo
- Publication number
- JP3213818B2 JP3213818B2 JP01192492A JP1192492A JP3213818B2 JP 3213818 B2 JP3213818 B2 JP 3213818B2 JP 01192492 A JP01192492 A JP 01192492A JP 1192492 A JP1192492 A JP 1192492A JP 3213818 B2 JP3213818 B2 JP 3213818B2
- Authority
- JP
- Japan
- Prior art keywords
- holding member
- ultrasonic
- vibration
- ultrasonic transducer
- housed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Transducers For Ultrasonic Waves (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、間欠発信された超音波
の反射波を検知して障害物の存在を判別するようにした
超音波センサに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic sensor which detects reflected waves of intermittently transmitted ultrasonic waves to determine the presence of an obstacle.
【０００２】[0002]
【従来の技術】超音波センサより障害物に向けて超音波
パルスを間欠発信させたとき、障害物より返信されて来
る反射波を検知して、障害物の有無を判別するようにし
た超音波センサは公知であるが、この種の超音波センサ
は図３、図４に示したような構造をしている。すなわ
ち、このような超音波センサでは、超音波振動子１は、
先端に開口部５ａを形成した保持部材５で側面全体を取
り囲み、この保持部材５を更に成形品より成るハウジン
グ４内に収納した構造となっており、超音波振動子１に
駆動信号を与えたときに、内蔵された圧電素子１０を振
動させ、そのときに発生される超音波を保持部材５の先
端開口部５ａより放射させる構造となっている。ここ
に、超音波振動子１は、図３に見るように、円筒ケース
１１の内部上面に圧電素子１０を貼付け、この圧電素子
１０をリード線１２で下部導体１３に接続し、この下部
導体にリード線３ａ，３ｂを接続し、このリード線３
ａ，３ｂを円筒ケース１１の下方より引き出したシール
ド線３で被覆し導出させている。このような構造のもの
では、超音波振動子１のリード線３ａ，３ｂより駆動信
号が送られると、ピエゾ効果によって圧電素子１０は振
動して超音波を発生する。すなわち、圧電素子１０を、
図５に示したようなバ−スト信号で駆動させると、超音
波振動子１は、送波時間Ｔａの間バースト信号に応じて
振動して超音波を出力するが、バースト信号が停止した
後も、超音波振動子１の振動は、図６（ａ）に示したよ
うに残響時間Ｔｂの間は減衰しながら継続する。そこ
で、従来はこのような残響時間Ｔｂを短縮するため、超
音波振動子１の側面全体を上記した保持部材５で取り囲
んで加圧し防振させる構造をとっているが、このような
保持部材５で取り囲んだ構造のものでは図６（ｂ）に示
したように、超音波振動子１の残響時間Ｔｂが短縮され
る。2. Description of the Related Art When an ultrasonic pulse is intermittently transmitted from an ultrasonic sensor toward an obstacle, an ultrasonic wave is detected by detecting a reflected wave returned from the obstacle to determine the presence or absence of the obstacle. Although a sensor is known, this type of ultrasonic sensor has a structure as shown in FIGS. That is, in such an ultrasonic sensor, the ultrasonic vibrator 1
The entire side surface is surrounded by a holding member 5 having an opening 5a formed at the tip, and the holding member 5 is further housed in a housing 4 made of a molded product. Sometimes, the built-in piezoelectric element 10 is vibrated, and the ultrasonic wave generated at that time is radiated from the distal end opening 5a of the holding member 5. Here, as shown in FIG. 3, the ultrasonic vibrator 1 has a piezoelectric element 10 adhered to the inner upper surface of a cylindrical case 11, and the piezoelectric element 10 is connected to a lower conductor 13 by a lead wire 12. Connect the lead wires 3a and 3b, and
a and 3b are covered with a shield wire 3 drawn out from below the cylindrical case 11 and led out. In such a structure, when a drive signal is sent from the lead wires 3a and 3b of the ultrasonic vibrator 1, the piezoelectric element 10 vibrates by the piezo effect to generate ultrasonic waves. That is, the piezoelectric element 10 is
When driven by a burst signal as shown in FIG. 5, the ultrasonic vibrator 1 vibrates according to the burst signal during the transmission time Ta and outputs ultrasonic waves, but after the burst signal is stopped. However, the vibration of the ultrasonic transducer 1 continues to attenuate during the reverberation time Tb as shown in FIG. Therefore, conventionally, in order to shorten such a reverberation time Tb, a structure is adopted in which the entire side surface of the ultrasonic vibrator 1 is surrounded by the above-described holding member 5 and pressurized to prevent vibration. 6B, the reverberation time Tb of the ultrasonic vibrator 1 is shortened, as shown in FIG.
【０００３】[0003]
【発明が解決しようとする課題】ところが、図４に示し
たように、超音波振動子１の側面全体を保持部材５で加
圧させ防振保持させてから、更に成形品で形成されたハ
ウジング５内に収納させると、超音波振動子１の側面か
ら発生した振動が保持部材５を介してハウジング４側へ
伝わり、ここで生じた振動が保持部材５を伝搬して超音
波振動子１側に返され、このような振動干渉のため、残
響時間Ｔｂがかえって不安定となって、図７に示したよ
うに残響時間Ｔｂが長びいてしまい、その結果近距離分
解能が低下するという問題点があつた。本発明は、上記
問題点を解決することを目的とするものであり、超音波
振動子の保持部材を成形品で構成されたハウジングに収
納させた場合にも、不安定要素となる振動干渉を抑制し
て残響特性を改善することにより、近距離分解能を向上
させた超音波センサを提供することを目的としている。However, as shown in FIG. 4, the entire side surface of the ultrasonic vibrator 1 is pressurized by the holding member 5 so as to be vibration-proof and held, and then the housing is formed of a molded product. When housed in the ultrasonic transducer 1, the vibration generated from the side surface of the ultrasonic vibrator 1 is transmitted to the housing 4 side via the holding member 5, and the vibration generated here propagates through the holding member 5 and the ultrasonic vibrator 1 side And the remaining
The reverberation time Tb becomes rather unstable, and the reverberation time Tb becomes longer as shown in FIG. 7, resulting in a problem that the short-range resolution is reduced. An object of the present invention is to solve the above-described problems. Even when a holding member of an ultrasonic vibrator is housed in a housing formed of a molded product, vibration interference that becomes an unstable element is prevented. It is an object of the present invention to provide an ultrasonic sensor with improved short-range resolution by suppressing and improving reverberation characteristics.
【０００４】[0004]
【課題を解決するための手段】請求項１に記載の超音波
センサは、内部上面に圧電素子を有する超音波振動子
を、超音波を送受信するための開口部を有した保持部材
で、側面より取り囲んでから、保持部材を成形品より成
るハウジング内に収納した構造とされた超音波センサに
おいて、保持部材は、開口部を有する中空部を有し、且
つ、中空部の開口部の先端の内周面に、中空部の中心方
向に張り出すように設けられた凸状部を有し、超音波振
動子を保持部材の中空部内に収容した際に、超音波振動
子の下端の振動の腹部分が、保持部材の中空部内に収容
した際に、保持部材の中空部の底隅部で加圧保持され、
超音波振動子の圧電素子に最も近い部分である、振幅の
大きい振動の腹部分が凸状部で加圧保持され、且つ、超
音波振動子と保持部材との間には、保持部材の中空部の
底隅部と保持部材の中空部の先端の内周面に設けられて
いる凸状部との間の領域に隙間が形成されることによ
り、超音波発生時に超音波振動子の側面の腹部分のみを
加圧防振するように、保持部材の内部に凸状部を設けた
構造とした。According to a first aspect of the present invention, there is provided an ultrasonic sensor comprising: an ultrasonic vibrator having a piezoelectric element on an inner upper surface; a holding member having an opening for transmitting and receiving ultrasonic waves; In the ultrasonic sensor having a structure in which the holding member is housed in a housing made of a molded product after being surrounded, the holding member has a hollow portion having an opening, and
The center of the hollow part on the inner peripheral surface at the tip of the opening of the hollow part.
Having a protruding portion provided so as to protrude in the
When the moving element is housed in the hollow part of the holding member,
Antinode of vibration at the lower end of the child is housed in the hollow part of the holding member
When pressed, it is pressed and held at the bottom corner of the hollow part of the holding member,
The portion of the ultrasonic transducer closest to the piezoelectric element
The antinode of the large vibration is pressed and held by the convex part, and
Between the acoustic transducer and the holding member, the hollow part of the holding member
Provided on the inner peripheral surface at the bottom corner and at the tip of the hollow part of the holding member
Gaps are formed in the area between
That is, a convex portion is provided inside the holding member so that only the antinode of the side surface of the ultrasonic vibrator is subjected to pressurized vibration isolation when generating ultrasonic waves.
【０００５】[0005]
【作用】上記構造によれば、超音波振動子より超音波を
発生させたとき、前面の振動と同時に振動する超音波振
動子の側面の腹部分、つまり振幅の大きな部分のみを保
持部材に形成した凸状部で加圧して振動を抑制する構造
となっているので、超音波振動子の側面より発生した振
動が保持部材を介して成形品のハウジングに伝達され、
ここでの振動が超音波振動子の側面に干渉を与えること
が防止できるので、残響振動の不安定さが解消される。According to the above structure, when an ultrasonic wave is generated from the ultrasonic vibrator, only the antinode portion of the side surface of the ultrasonic vibrator vibrating simultaneously with the vibration of the front surface, that is, only the large amplitude portion is formed on the holding member. Vibration generated from the side of the ultrasonic vibrator is transmitted to the housing of the molded product via the holding member, because it has a structure that suppresses vibration by pressing with the convex part
Since the vibration here can prevent interference with the side surface of the ultrasonic vibrator, the instability of reverberation vibration is eliminated.
【０００６】[0006]
【実施例】以下に、本発明の一実施例を示す。図１は本
発明の要部を示した保持部材の構造を示す図であり、図
２は超音波振動子を保持部材内に収容した状態の断面構
造を示している。図に見るように、保持部材２は防振性
に優れたゴム材などで製され、先端に開口部２ａを形成
し、下端中央には超音波振動子１の下方より導出された
シールド線３を貫通させる孔２ｃを形成した中空部２ｂ
を有した円筒体に形成されており、上記開口部２ａの内
周面には、超音波振動子１の前面より超音波を出力させ
たとき、側面の腹部分を加圧保持させる凸状部２ａが形
成されている。ここに、超音波振動子１は、図３にも示
したように、超音波発生時にその側面より３ヶ所の振幅
が大きい腹部分と２ヶ所の振幅が小さい節部分が現れる
ように振動するものを想定しており、図例では超音波振
動子１の圧電素子１０に最も近い部分である振幅の大き
い腹の部分は上記した凸状部２ａで、超音波振動子１の
下端の腹部分は保持部材２の底隅部２ｄで加圧保持され
ている。また、図１に示した構造のものでは、超音波振
動子１を保持部材２内に収容させたときには、凸状部２
ａと底隅部２ｄとの間には隙間２ｅが形成されるため、
超音波振動子１の隙間２ｅに対応した側面部分が振動し
ても、隙間２ｅが存在するために振動が保持部材５に伝
達するのが防止され、それだけ残響時間を安定化させる
ことが出来る。このように、本発明の超音波センサによ
れば、従来構造のように超音波振動子の側面全体を保持
部材で加圧保持するのではなく、振動の大きい腹部分の
みを加圧保持しているため、超音波振動子の側面が振動
したときに振動が保持部材へ伝達するが抑制される。こ
のため、超音波振動子を保持部材に収容させ、更に保持
部材を成形品ハウジングに収納した構造としても残響時
間の不安定さがなくなり、残響時間の短い超音波センサ
が安価に得られ、安定した近距離分解能を持つことが可
能となる。また、このような構造のものでは、外的要因
によりハウジング４が振動しても保持部材２の凸状部２
ａが超音波振動子１の側面の腹部分に圧接しているた
め、ハウジング４の振動が超音波振動子１へ伝搬される
こともない。このため、ハウジング４の振動による悪影
響も受けにくくなり、外的要因による誤動作防止も可能
となる。An embodiment of the present invention will be described below. FIG. 1 is a diagram showing a structure of a holding member showing a main part of the present invention, and FIG. 2 shows a cross-sectional structure in a state where an ultrasonic vibrator is accommodated in the holding member. As shown in the figure, the holding member 2 is made of a rubber material or the like having excellent vibration damping properties, has an opening 2a at the tip, and has a shield wire 3 led out from below the ultrasonic vibrator 1 at the center of the lower end. 2b formed with a hole 2c through which
The formed into a cylindrical body having, on the inner peripheral surface of the opening 2a, when to output a ultrasonic wave from the front surface of the ultrasonic vibrator 1, the convex portion to the ventral portion of the side dwell 2a is formed. Here, as shown in FIG. 3, the ultrasonic vibrator 1 vibrates so that, when an ultrasonic wave is generated, an antinode part having three large amplitudes and a node part having two small amplitudes appear from its side. In the illustrated example, the antinode of the ultrasonic transducer 1 which is closest to the piezoelectric element 10 and whose antinode has a large amplitude is the above-mentioned convex part 2a, and the antinode of the lower end of the ultrasonic transducer 1 is The holding member 2 is pressed and held at the bottom corner 2d. Further, those of the structure shown in FIG. 1, when allowed housed in the holding member 2 of the ultrasonic vibrator 1, the convex portion 2
Since a gap 2e is formed between a and the bottom corner 2d,
Even if the side portion corresponding to the gap 2e of the ultrasonic vibrator 1 vibrates, the vibration is prevented from being transmitted to the holding member 5 due to the presence of the gap 2e, and the reverberation time can be stabilized accordingly. As described above, according to the ultrasonic sensor of the present invention, the entire side surface of the ultrasonic vibrator is not pressurized and held by the holding member as in the conventional structure, but only the antinode portion having large vibration is pressurized and held. Therefore, transmission of the vibration to the holding member when the side surface of the ultrasonic vibrator vibrates is suppressed. For this reason, even when the ultrasonic transducer is housed in the holding member and the holding member is housed in the molded product housing, the instability of the reverberation time is eliminated. It becomes possible to have the short distance resolution which was improved. Further, with such a structure, even if the housing 4 vibrates due to an external factor, the convex portion 2
Since “a” is in pressure contact with the antinode portion on the side surface of the ultrasonic transducer 1, the vibration of the housing 4 is not transmitted to the ultrasonic transducer 1. For this reason, it is hard to be affected by the vibration of the housing 4, and it is possible to prevent malfunction due to external factors.
【０００７】[0007]
【発明の効果】以上のように本発明によれば、超音波振
動子の側面のうちの振動が大きくなる部分のみを保持部
材で加圧して防振させる構造となっているので、ハウジ
ングに収納した場合の残響時間を短縮することができ、
そのため近距離分解能が向上され、近距離死角も縮小さ
れる。また、従来構造に比べて、超音波振動子の側面と
保持部材との接触面積が減少したため、この部分の摩擦
力も小さくなって、超音波振動子を保持部材内に容易に
挿着でき、組立時の作業性も向上される。As described above, according to the present invention, since only the portion of the side surface of the ultrasonic vibrator where the vibration is increased is pressurized by the holding member to prevent vibration, the ultrasonic vibrator is housed in the housing. Can reduce the reverberation time,
Therefore, the short distance resolution is improved and the short distance blind spot is reduced. Also, as compared with the conventional structure, the contact area between the side surface of the ultrasonic vibrator and the holding member is reduced, so that the frictional force at this portion is also reduced, so that the ultrasonic vibrator can be easily inserted into the holding member, and assembling can be performed. Workability at the time is also improved.
【図１】本発明の超音波センサの要部をなす保持部材の
半裁縦断面構造図である。FIG. 1 is a half longitudinal sectional structure view of a holding member forming a main part of an ultrasonic sensor according to the present invention.
【図２】本発明の超音波センサの一実施例を示す図で、
保持部材内に収容された超音波振動子を更にハウジング
内に収容させた構造を示した縦断面構造図である。FIG. 2 is a view showing one embodiment of an ultrasonic sensor according to the present invention;
FIG. 7 is a longitudinal sectional structural view showing a structure in which an ultrasonic transducer housed in a holding member is further housed in a housing.
【図３】超音波振動子の半裁縦断面構造図である。FIG. 3 is a half longitudinal sectional structure view of an ultrasonic transducer.
【図４】従来の超音波センサの縦断面構造を示す図であ
る。FIG. 4 is a view showing a longitudinal sectional structure of a conventional ultrasonic sensor.
【図５】超音波振動子の駆動動作を示す図である。FIG. 5 is a diagram showing a driving operation of the ultrasonic transducer.
【図６】（ａ），（ｂ）は超音波振動子の残響時間を示
す図である。FIGS. 6A and 6B are diagrams showing reverberation times of an ultrasonic transducer. FIGS.
【図７】従来の超音波センサにおける問題点を示す図で
ある。FIG. 7 is a diagram showing a problem in a conventional ultrasonic sensor.
１・・・超音波振動子 ２・・・保持部材 ２ａ・・・凸条部 ４・・・成形品ハウジング DESCRIPTION OF SYMBOLS 1 ... Ultrasonic vibrator 2 ... Holding member 2a ... Protrusion part 4 ... Molded product housing
Claims (1)
を、超音波を送受信するための開口部を有した保持部材
で、側面より取り囲んでから、前記保持部材を成形品よ
り成るハウジング内に収納した構造とされた超音波セン
サにおいて、前記保持部材は、開口部を有する中空部を有し、且つ、
前記中空部の開口部の先端の内周面に、前記中空部の中
心方向に張り出すように設けられた凸状部を有し、 前記超音波振動子を前記保持部材の中空部内に収容した
際に、 前記超音波振動子の下端の振動の腹部分が、前記保持部
材の中空部内に収容した際に、前記保持部材の中空部の
底隅部で加圧保持され、 前記超音波振動子の圧電素子に最も近い部分である、振
幅の大きい振動の腹部分が前記凸状部で加圧保持され、
且つ、 前記超音波振動子と前記前記保持部材との間には、前記
保持部材の中空部の底隅部と前記保持部材の中空部の先
端の内周面に設けられている凸状部との間の領域に隙間
が形成されることにより、 超音波発生時に超音波振動子の側面の腹部分のみを加圧
防振するように、保持部材の内部に凸状部を設けた構造
とした超音波センサ。(1)Has a piezoelectric element on the inner top surfaceUltrasonic transducer
A holding member having an opening for transmitting and receiving ultrasonic waves
Then, after surrounding from the side, the holding member is
Ultrasonic sensor housed in a housing
In sa,The holding member has a hollow portion having an opening, and
On the inner peripheral surface at the tip of the opening of the hollow part,
It has a convex portion provided so as to project in the center direction, The ultrasonic transducer was housed in the hollow part of the holding member.
At that time, The antinode of the vibration at the lower end of the ultrasonic transducer is
When housed in the hollow part of the material, the hollow part of the holding member
Pressed and held at the bottom corner, The vibrator, which is the portion of the ultrasonic transducer closest to the piezoelectric element,
The antinode portion of the vibration having a large width is held under pressure by the convex portion,
and, Between the ultrasonic transducer and the holding member, the
The bottom corner of the hollow portion of the holding member and the tip of the hollow portion of the holding member
A gap is formed in the region between the convex portion provided on the inner peripheral surface of the end.
Is formed, Pressurizes only the antinode on the side of the ultrasonic transducer when generating ultrasonic waves
A structure in which a convex portion is provided inside the holding member so as to prevent vibration
Ultrasonic sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01192492A JP3213818B2 (en) | 1992-01-27 | 1992-01-27 | Ultrasonic sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01192492A JP3213818B2 (en) | 1992-01-27 | 1992-01-27 | Ultrasonic sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05207594A JPH05207594A (en) | 1993-08-13 |
| JP3213818B2 true JP3213818B2 (en) | 2001-10-02 |
Family
ID=11791236
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP01192492A Expired - Fee Related JP3213818B2 (en) | 1992-01-27 | 1992-01-27 | Ultrasonic sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3213818B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5741703B2 (en) * | 2011-10-21 | 2015-07-01 | 株式会社村田製作所 | Ultrasonic transducer |
| JP6581712B2 (en) * | 2013-08-05 | 2019-09-25 | キヤノン株式会社 | Ultrasonic transmission device, ultrasonic reception device, sheet discrimination device and image forming device |
-
1992
- 1992-01-27 JP JP01192492A patent/JP3213818B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05207594A (en) | 1993-08-13 |
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