JPS6127280Y2 - - Google Patents

Description

【考案の詳細な説明】[Detailed explanation of the idea]

本考案は圧電磁器素子板を金属振動板上に貼り
合せて成る圧電振動子を音響効果等を有するケー
スに支持構成した圧電ブザー発音体の改良に関す
る。 圧電ブザーは、小型、薄型、軽量で消費電力が
小さく、長寿命であり更にトランジスター回路と
の組合せによつて種々の音色を発生できる利点を
有するため従来の電磁ブザーの替りに、各種電子
機器の信号音、警報、報知用として時計、防災機
器から玩具まで広い分野で使用されている。 このように用途が広がるにつれ、音色の多様
化、大音量化、信頼性の向上、装着のし易さや低
価格化等の要求が強くなつている。 考案者らはこれ等の要求に対して、小型軽量で
低周化が可能でしかも回路基板等への装着のし易
い圧電ブザー発音体を考案した。（実開昭56〜
88298号公報及び実開昭56〜92199号公報）しかし
ながら、この圧電ブザー発音体は上記の利点があ
るものの機器の中に組込んだ場合に音圧が低下す
る場合があつたり、防塵性、防湿性の面で問題が
あり、これらの欠点に対し種々検討した結果本考
案に想到したものである。 圧電ブザーの本体は第１図に示す如く、圧電磁
器素子板３を金属振動板２に接着剤等で貼合わせ
た圧電振動子１，５であり、リード線４に駆動回
路から供給される交番電圧により屈曲振動を起し
音を発生するものである。第１図イは２端子型振
動子、ロは３端子型振動子であり、後者は自励発
進型駆動回路によつて利用されるもので圧電磁器
素子板の上面にフイードバツク電極が設けられリ
ード線４′を附して利用される。この圧電振動子
は屈曲振動において圧電素子板の直径円周近辺に
振動の節があり、この節を支持固定する場合が振
動効率が良いが、支持しにくいため通常金属振動
板２の外周でプラスチツクケース等に支持固定し
たものを発音体として利用することも多い。第２
図はその一例を示すものであり、圧電振動子８が
開孔１０′を有するケース１０の内側にその外周
部で固定した発音体６として製造し、基板７にネ
ジ９等によつて固定し、同じ基板上に装着された
回路素子１５等から駆動回路（図示せず）によつ
て音を発生する。この場合、ケース１０は固定さ
れており、振動は振動子８のみで生ずる。そして
これらは外囲ケース１２の中に収納され発生する
音は外部で利用することが多い。外囲ケースには
音響室１３を形成するための音響筒１３′と開孔
１２を設けることが多い。このような場合、発音
体６を基板に取り付けるのが面倒であり、しかも
振動子８は振動の節で支持されるために円周状に
軟質の接着剤を使用して支持するため組立てが面
倒であり、製造コスト上問題が多い。 更にこのケース固定型発音体を外囲ケース内に
収納された場合外部で聞く音圧が更に低下する等
の問題があつた。このような問題を解決するため
考案者らは先に第３図に示す構造の発音体を開発
した。即ち圧電振動子１８はケース１７の内側に
金属振動板の外周部で支持固定されており、圧電
素子板の電極面及び金属振動板にハンダ付け等に
よつて電気的に接続された給電用を兼ねた導電性
でかつばね性を持つた複数本の端子１９で支持固
定したものである。端子の先端は基板７に挿入し
ハンダ２０によつて固定される。このような構造
の圧電ブザー発音体は圧電振動子１８の屈曲振動
に伴つてケース１７全体が一体となつて振動する
ために振動効率が高く、しかも小型の振動子によ
つて可成り低周波で高い音を発生することがで
き、更に強度の弱い通常のリード線に較べてはる
かに強固であり、基板への装着も他の回路素子の
装着と同じようにすることができるなどの利点を
もつており、各種用途の実用に供している。 しかしながら、このケース一体振動型発音体１
６を第３図に示す如く外囲ケース１１の中に組込
まれた場合に外部で利用する音圧が低下したり、
ビビリなどの音が不安定になる場合が対象機器に
よつては発生した。これはこのタイプの発音体の
場合ケース１７と振動子８は一体となつて振動す
るため外囲ケースの一部に接触するとか発音体１
６と外囲ケースの音響筒１３′又は外囲ケース間
の隙間１４から音の１部が外囲ケース内に漏れる
ためと思われる。更にこの隙間を設ける必要があ
るために外囲ケースの開孔１２から侵入する塵と
湿気のために機器内部の回路部品への悪影響が起
る場合もあつた。この問題を解決するため種々検
討した結果次に述べる考案に想到した。 第４図は本考案の圧電ブザー発音体の実施例を
示す断面図である。発音体１６は上記に述べたケ
ース一体振動型発音体であり、ケース１７の上部
の外囲ケースの開孔１２側に面する箇所に発泡ポ
リエチレン樹脂等の緩衝部材２１を貼り付けたも
のである。この緩衝部材としては軟質でクツシヨ
ン性があり振動伝達効率の高い独立気泡体の樹脂
が最も好ましい。独立気泡体であれば透水せず湿
気を殆んど通さず耐熱性、断熱性に優れて発音体
や機器内の回路部品の保護にも役立つ。実用に際
しては上記の緩衝部材シートをケース１７の上面
の大きさに合わせた大きさに切り取り適当な接着
剤で貼り付けるだけでよい。緩衝部材として軟質
の樹脂でも連続気孔を有するスポンジ等では以下
に述べる本考案の効果はでてこない。 上記独立気泡体の緩衝部材の厚みは特に限定は
ないが２〜10mmの範囲が実用的である。 第５図は第４図に示した本考案の圧電ブザー発
音体を外囲ケース１１に収納する場合の実施例を
示す断面図である。緩衝部材２１を貼り付けた発
音体１６を外囲ケースの開孔１２の下にくるよう
に基板７に他の回路部品１５等と共に装着し、外
囲ケースの音響筒１３′に緩衝部材２１の上面が
密着するように外囲ケース１１内に取り付けられ
る。このようにすることにより、圧電ブザー発音
体１６が一体で振動しても、密着している緩衝部
材２１はその振動を抑制することなく、ケース１
７の上面の振動をたて方向に効率よく表面に伝搬
させることにより音響室１３の音響増巾効果が充
分得られ、かえつて外部で利用できる音量が高く
なり、しかも開孔１２と外囲ケース内部の間には
隙間が完全になくなつたことにより防湿性、防塵
性の面でも抜群の効果を発揮することができた。 次に本考案による圧電ブザー発音体による実施
例を従来の発音体の場合と比較した。 第１表は、第２図で示したケース固定型の発音
体（振動子35φ）と第３図及び第４図（本考案）
で示したケース一体振動型発音体（振動子27φ）
の自励発振回路で駆動した場合の10cm前方での音
圧を種々の状態で比較したものである。 即ち、発音体を基板上に装着した状態(イ)では両
者共同じ音圧であるが、ケース固定型の場合は緩 The present invention relates to an improvement in a piezoelectric buzzer sounding body in which a piezoelectric vibrator made by bonding a piezoelectric ceramic element plate to a metal diaphragm is supported in a case having acoustic effects. Piezoelectric buzzers are small, thin, lightweight, have low power consumption, have a long lifespan, and can generate various tones when combined with transistor circuits, so they are used in various electronic devices instead of conventional electromagnetic buzzers. It is used in a wide range of fields, from clocks, disaster prevention equipment, to toys, for signal tones, alarms, and notifications. As the applications have expanded in this way, there has been a growing demand for more diverse tones, higher volumes, improved reliability, ease of installation, and lower prices. In response to these demands, the inventors devised a piezoelectric buzzer sounding body that is small, lightweight, can have a low frequency, and is easy to attach to a circuit board or the like. (Jitsukai 1986~
However, although this piezoelectric buzzer sounding body has the above-mentioned advantages, the sound pressure may decrease when it is incorporated into equipment, and it is not dust-proof or moisture-proof. There are problems in terms of performance, and as a result of various studies to address these drawbacks, the present invention was conceived. As shown in Fig. 1, the main body of the piezoelectric buzzer is a piezoelectric vibrator 1, 5 made by bonding a piezoelectric ceramic element plate 3 to a metal diaphragm 2 with an adhesive or the like, and an alternating current supplied from a drive circuit to a lead wire 4. It causes bending vibration due to voltage and generates sound. Figure 1 A shows a two-terminal type vibrator, and B shows a three-terminal type vibrator.The latter is used in a self-excited starting type drive circuit, and has a feedback electrode on the top surface of the piezoelectric ceramic element plate. It is used with a line 4' attached. This piezoelectric vibrator has a vibration node near the diameter of the piezoelectric element plate during bending vibration, and vibration efficiency is good if this node is supported and fixed, but since it is difficult to support it, the outer periphery of the metal diaphragm 2 is usually covered with a plastic case. It is often used as a sounding body by supporting and fixing it on a holder or the like. Second
The figure shows one example, in which a piezoelectric vibrator 8 is manufactured as a sounding body 6 whose outer periphery is fixed inside a case 10 having an opening 10', and is fixed to a substrate 7 with screws 9 or the like. , a drive circuit (not shown) generates sound from circuit elements 15 and the like mounted on the same board. In this case, the case 10 is fixed and vibrations occur only in the vibrator 8. These are often housed in the outer case 12 and the generated sound is used externally. The outer case is often provided with an acoustic tube 13' and an opening 12 for forming an acoustic chamber 13. In such a case, it is troublesome to attach the sounding body 6 to the board, and furthermore, since the vibrator 8 is supported at the nodes of vibration, it is difficult to assemble it because it is supported using a soft adhesive around the circumference. Therefore, there are many problems in terms of manufacturing cost. Furthermore, when this case-fixed sounding body is housed in an outer case, there is a problem that the sound pressure heard outside is further reduced. In order to solve these problems, the inventors previously developed a sounding body having the structure shown in FIG. That is, the piezoelectric vibrator 18 is supported and fixed inside the case 17 by the outer periphery of a metal diaphragm, and a power supply device is electrically connected to the electrode surface of the piezoelectric element plate and the metal diaphragm by soldering or the like. It is supported and fixed by a plurality of terminals 19 which are conductive and have spring properties. The tip of the terminal is inserted into the board 7 and fixed with solder 20. The piezoelectric buzzer sounding body having such a structure has high vibration efficiency because the entire case 17 vibrates as a unit with the bending vibration of the piezoelectric vibrator 18. Moreover, the small vibrator allows it to operate at a considerably low frequency. It can generate high-pitched sounds, is much stronger than ordinary lead wires, and has the advantage that it can be attached to the board in the same way as other circuit elements. It is used for various practical purposes. However, this case-integrated vibrating sounding body 1
6 is incorporated into the outer case 11 as shown in FIG. 3, the sound pressure used externally decreases,
Depending on the target device, the sound such as chatter may become unstable. In the case of this type of sounding body, the case 17 and the vibrator 8 vibrate as a unit, so the sounding body 1 may come into contact with a part of the outer case.
This is thought to be because a part of the sound leaks into the outer case from the acoustic cylinder 13' of the outer case and the sound tube 13' of the outer case, or from the gap 14 between the outer case and the sound tube 13'. Furthermore, since it is necessary to provide this gap, there are cases in which dust and moisture entering through the opening 12 in the outer case have an adverse effect on the circuit components inside the device. As a result of various studies to solve this problem, we came up with the idea described below. FIG. 4 is a sectional view showing an embodiment of the piezoelectric buzzer sounding body of the present invention. The sounding body 16 is the case-integrated vibration type sounding body described above, and has a buffer member 21 made of foamed polyethylene resin or the like affixed to the upper part of the case 17 facing the opening 12 side of the outer case. . The most preferable material for this cushioning member is a closed-cell resin that is soft, has cushioning properties, and has high vibration transmission efficiency. Closed-cell foams are impermeable to water, almost impermeable to moisture, and have excellent heat resistance and insulation properties, making them useful for protecting the sounding body and circuit components inside equipment. In practical use, it is sufficient to simply cut the above-mentioned cushioning member sheet into a size that matches the size of the upper surface of the case 17 and paste it with a suitable adhesive. Even if a soft resin is used as a cushioning member, the effects of the present invention described below will not be achieved when using a sponge or the like having continuous pores. The thickness of the closed cell cushioning member is not particularly limited, but a range of 2 to 10 mm is practical. FIG. 5 is a sectional view showing an embodiment in which the piezoelectric buzzer sounding body of the present invention shown in FIG. 4 is housed in the outer case 11. The sounding body 16 with the buffer member 21 pasted thereon is attached to the board 7 along with other circuit components 15, etc., so as to be below the aperture 12 of the outer case, and the buffer member 21 is attached to the sound cylinder 13' of the outer case. It is installed in the outer case 11 so that the upper surface is in close contact with the outer case 11. By doing this, even if the piezoelectric buzzer sounding body 16 vibrates as a unit, the buffer member 21 that is in close contact with the case 1 does not suppress the vibration.
By efficiently propagating the vibration of the upper surface of 7 to the surface in the vertical direction, a sufficient acoustic amplification effect of the acoustic chamber 13 can be obtained, and the sound volume that can be used externally can be increased. Since there are no gaps between the insides, it is extremely effective in terms of moisture and dust resistance. Next, an embodiment using a piezoelectric buzzer sounding body according to the present invention was compared with a conventional sounding body. Table 1 shows the case-fixed sounding body (vibrator 35φ) shown in Fig. 2, and Figs. 3 and 4 (this invention).
Case-integrated vibrating sounding body shown in (vibrator 27φ)
This is a comparison of the sound pressure at a distance of 10 cm in front of the device under various conditions when driven by a self-excited oscillation circuit. In other words, when the sounding body is mounted on the board (a), the sound pressure is the same in both cases, but in the case of the case fixed type, the sound pressure is the same.

【表】 衝部材を貼付けることによつて27dBも低下する
が本考案の場合は6dBしか低下していない。又、
緩衝部材なしで外囲ケースに収納した場合両者と
も音圧が低下するが、緩衝部材（４mm）を貼付け
た状態で外囲ケースに収納した場合ニは驚くべき
ことに単体(イ)の時よりも更に音圧が高くなり、従
来のケース固定型の場合は20dB低下することが
わかる。即ち、本考案の効果は圧電振動子とこれ
を支持するケースとが一体となつて振動するケー
ス一体振動型発音体 効果を発揮することがわ
かる。この場合開孔１７′がない場合も効果は同
じである。 上記は第１図の３端子型振動子ロを利用した場
合について述べたが、２端子型振動子イを用いて
も第３図の発音体１６の端子１９の２本のみ給電
用リード線として導通させることによつて使用可
能であり、緩衝部材２１を貼付けることによる効
果は同じである。又、第５図は緩衝部材２１を外
囲ケースの音響筒１３′に密着させた例であるが
この音響筒が無い場合には外囲ケースの開孔１２
の下に直接密着させても本考案の効果は同じであ
り、緩衝部材を環状のものにして発音体１６の上
面に貼合せるのでなく外囲ケースの内側に予め貼
付けておいて第５図の如き状態で用いる発音体構
造も本考案の範囲である。 以上説明した如く、外囲ケースに収納して用い
る発音体として音量が高く、かつ安定で防湿性、
防塵性の優れた信頼性の高い圧電ブザー発音体と
して実用価値が高く応用範囲がますます広がるも
のである。[Table] Attaching a shock member reduces the noise by 27 dB, but in the case of the present invention, the reduction is only 6 dB. or,
When both are stored in the outer case without a buffer material, the sound pressure decreases in both cases, but when the shock absorber (4 mm) is attached and the sound pressure is stored in the outer case, D is surprisingly lower than when it is alone (A). It can be seen that the sound pressure becomes even higher, and in the case of the conventional fixed case type, it decreases by 20 dB. That is, it can be seen that the effect of the present invention is that the piezoelectric vibrator and the case supporting the vibrator vibrate as one, producing a case-integrated vibrating sounding body effect. In this case, the effect is the same even if there is no opening 17'. The above describes the case where the three-terminal type vibrator B in Figure 1 is used, but even if the two-terminal type vibrator A is used, only the two terminals 19 of the sounding body 16 in Figure 3 are used as the power supply lead wires. It can be used by making it conductive, and the effect of attaching the buffer member 21 is the same. FIG. 5 shows an example in which the buffer member 21 is brought into close contact with the acoustic tube 13' of the outer case, but if this acoustic tube is not provided, the opening 12 of the outer case
The effect of the present invention is the same even if it is attached directly to the bottom of the sounding body 16, and instead of making the buffer member into an annular shape and attaching it to the top surface of the sounding body 16, it is attached in advance to the inside of the outer case, as shown in FIG. The structure of the sounding body used in such conditions is also within the scope of the present invention. As explained above, as a sounding device that is housed in an outer case, it has a high volume, is stable, and is moisture-proof.
The piezoelectric buzzer has high practical value as a highly reliable piezoelectric buzzer sounding body with excellent dust resistance, and its range of applications is expanding.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は圧電振動子の斜視図でイが２端子型振
動子、ロが３端子型振動子であり、第２図は市販
のケース固定型発音体を基板、外囲ケースに収納
した場合の従来例を示す断面図、第３図はケース
一体振動型発音体の断面図、第４図は本考案の発
音体の実施例を示す断面図、第５図は本考案の発
音体を外囲ケースに収納した場合の実施例を示す
断面図である。 １，５，８，１８；圧電振動子、２；金属振動
板、３；圧電磁器振動板、４，４′；リード線、
６，１６；発音体、７；基板、９；ネジ、１０，
１７；ケース、１１；外囲ケース、１０′，１
２；開孔、１３；音響室、１３′；音響筒、１
４；隙間、１５；回路部品、１９；端子、２０；
ハンダ、２１；緩衝部材。 Figure 1 is a perspective view of a piezoelectric vibrator, where A is a two-terminal type vibrator, B is a three-terminal type vibrator, and Figure 2 is a case in which a commercially available case-fixed sounding body is housed in a substrate and an outer case. 3 is a cross-sectional view of a case-integrated vibrating sounding body, FIG. 4 is a cross-sectional view showing an embodiment of the sounding body of the present invention, and Figure 5 is a cross-sectional view of a conventional example of the sounding body of the present invention. FIG. 3 is a cross-sectional view showing an embodiment when the device is housed in a surrounding case. 1, 5, 8, 18; piezoelectric vibrator, 2; metal diaphragm, 3; piezoelectric ceramic diaphragm, 4, 4'; lead wire,
6, 16; sounding body, 7; board, 9; screw, 10,
17; case, 11; outer case, 10', 1
2; Opening, 13; Acoustic chamber, 13'; Acoustic tube, 1
4; Gap, 15; Circuit component, 19; Terminal, 20;
Solder, 21; buffer member.

Claims (1)

【実用新案登録請求の範囲】 (1) 外囲ケース内に収納されて利用する、圧電振
動子の外周がケース内側に支持固定され、ばね
性を有する端子に支持されてケースと圧電振動
子とが一体になつて振動するケース一体振動型
発音体において、外囲ケースの開孔部と上記ケ
ースの上面の間に軟質で独立気泡体の緩衝部材
を密着してなることを特徴とする圧電ブザー発
音体。 (2) 実用新案登録請求の範囲第１項において、緩
衝部材が厚み２〜10mmで独立気泡体の発泡ポリ
エチレン樹脂であることを特徴とする圧電ブザ
ー発音体。 (3) 実用新案登録請求の範囲第１項において、該
緩衝部材が圧電振動子を支持するケースの上面
に接着固定されていることを特徴とする圧電ブ
ザー発音体。 (4) 実用新案登録請求の範囲第１項において、該
緩衝部材が外囲ケース内側の音響筒と発音体と
の間に密着されてなることを特徴とする圧電ブ
ザー発音体。[Claims for Utility Model Registration] (1) The outer periphery of a piezoelectric vibrator, which is housed and used in an outer case, is supported and fixed inside the case, and is supported by terminals having spring properties to connect the case and the piezoelectric vibrator. A piezoelectric buzzer characterized in that a case-integrated vibrating sounding body vibrates as a unit, characterized in that a soft, closed-cell cushioning member is in close contact between an opening in an outer case and an upper surface of the case. pronunciation body. (2) Utility Model Registration Claim 1: The piezoelectric buzzer sounding element according to claim 1, characterized in that the cushioning member is a closed-cell foamed polyethylene resin having a thickness of 2 to 10 mm. (3) A piezoelectric buzzer sounding element according to claim 1, characterized in that the buffer member is adhesively fixed to the upper surface of a case that supports a piezoelectric vibrator. (4) A piezoelectric buzzer sounding body according to claim 1 of the utility model registration claim, characterized in that the buffer member is closely attached between the sound tube and the sounding body inside the outer case.