JP2006118397A - Piezoelectric diaphragm pump - Google Patents

Piezoelectric diaphragm pump Download PDF

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JP2006118397A
JP2006118397A JP2004305536A JP2004305536A JP2006118397A JP 2006118397 A JP2006118397 A JP 2006118397A JP 2004305536 A JP2004305536 A JP 2004305536A JP 2004305536 A JP2004305536 A JP 2004305536A JP 2006118397 A JP2006118397 A JP 2006118397A
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voltage
time
fluid
discharge
piezoelectric element
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JP4419790B2 (en
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Harutomo Kitahara
治倫 北原
Tsukasa Hojo
司 法上
Takeshi Nakasuji
威 中筋
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Panasonic Electric Works Co Ltd
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Matsushita Electric Works Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To reduce pulsation of delivered fluid by changing a control method of voltage applied on a piezoelectric element in a piezoelectric diaphragm pump. <P>SOLUTION: A diaphragm plate bends in a direction in which a space sucking and delivering fluid swells under an initial condition and fluid in the space is delivered by applying voltage on the piezoelectric element in this structure, and voltage apply on the piezoelectric element is controlled to keep voltage apply time (time t1 - time t3) for fluid delivery longer than voltage apply time (time t3 - time t4) for fluid suction. Consequently, the maximum value of instant flow rate in a delivery side becomes small and pulsation of delivery fluid is reduced as compared with that at a time that voltage apply time for suction and voltage apply time for delivery are equal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、圧電素子を用いたダイヤフラムポンプに関するものである。   The present invention relates to a diaphragm pump using a piezoelectric element.

従来の圧電ダイヤフラムポンプは、ダイヤフラム板のたわみが増減し、ポンプの筐体内部の空間の容積が増減することで吸入側の弁より動作流体を吸入し、吐出側の弁より動作流体を吐出する。ダイヤフラム板のたわみの増減は、円盤状の圧電素子の両面に設けられた電極に電圧が印加されることにより、圧電素子が変形することで実現される。   The conventional piezoelectric diaphragm pump sucks the working fluid from the suction side valve and discharges the working fluid from the discharge side valve as the deflection of the diaphragm plate increases and decreases, and the volume of the space inside the pump housing increases and decreases. . The increase / decrease in the deflection of the diaphragm plate is realized by deforming the piezoelectric element by applying a voltage to the electrodes provided on both sides of the disk-shaped piezoelectric element.

一般に、ポンプによる液体吐出用途の一つとして、燃料電池へのアルコールの微少量供給や、静電噴霧する水の供給などが挙げられる。これらの用途では、吐出先の液体の液面状態や表面位置が重要な問題となるため、吐出液体の流量は安定していることが望ましい。しかし、ダイヤフラムポンプ等の往復動ポンプでは、吸入行程と吐出行程が交互に行われることで動作するため、一般に脈動量が大きくなる。   In general, as a liquid discharge application by a pump, there is a supply of a small amount of alcohol to a fuel cell, supply of water to be electrostatically sprayed, or the like. In these applications, the liquid level and the surface position of the liquid at the discharge destination are important problems, so it is desirable that the flow rate of the discharged liquid be stable. However, since a reciprocating pump such as a diaphragm pump operates by alternately performing a suction stroke and a discharge stroke, the amount of pulsation generally increases.

この往復動ポンプにおける脈動量を小さくするための技術として、例えば特許文献１に開示されるように、プランジャ往復動型液体クロマトグラフ用ポンプにおいて、プランジャの液体吐出行程時間を液体吸入行程時間に比較して短くし、液体の脈動を小さくするプランジャ動作制御手段がある。なお、この特許文献１の従来技術として、送液ポンプにおいて、吸入行程時間を吐出行程時間に比べて短くすることが示されている。   As a technique for reducing the amount of pulsation in this reciprocating pump, for example, as disclosed in Patent Document 1, in a plunger reciprocating liquid chromatograph pump, the liquid discharge stroke time of the plunger is compared with the liquid suction stroke time. Therefore, there is a plunger operation control means for shortening and reducing the pulsation of the liquid. In addition, as a prior art of this patent document 1, it is shown that the suction stroke time is shortened compared with the discharge stroke time in the liquid feed pump.

また、ポンプではないが、例えば、特許文献２に開示されるように、一般に管路を流れる流体の脈動を低減させるための技術として、流体の脈動とは逆位相で同振幅の反転信号を出力し、該反転信号に応じて、管路の流体が導入される流体室に配された圧力調節部材に、脈動を打ち消す圧力変化を生じさせるように変位を与えるとともに、該圧力調節部材を流体の静圧に抗する方向に付勢する静圧低減手段が知られている。
特開昭６４−３２１６３号公報 特開平６−１０１７９３号公報 Although not a pump, for example, as disclosed in Patent Document 2, as a technique for reducing the pulsation of fluid flowing through a pipeline, an inverted signal having the same phase and the same amplitude as the fluid pulsation is output. In response to the inversion signal, the pressure adjusting member disposed in the fluid chamber into which the fluid in the pipeline is introduced is displaced so as to cause a pressure change that cancels the pulsation, and the pressure adjusting member is Static pressure reducing means for urging in a direction against static pressure is known.
JP-A 64-32163 JP-A-6-101793

しかしながら、上記特許文献１に示されるように、吐出行程時間を短くすると、ダイヤフラムポンプにおいては脈動がむしろ目立つことになり、また、同文献１の従来技術としての記載は、プランジャ式のポンプではキャビテーションの問題があることを説明するものであって、ダイヤフラム式のポンプで適用されるものではない。また、特許文献２に示される技術は、ダイヤフラム式ポンプにそのまま適用できるものではない。本発明は、上記問題点に鑑みてなされたもので、圧電素子に印加する電圧の制御方法を変更することで、吐出流体の脈動を低減することができる圧電ダイヤフラムポンプを提供することを目的とする。   However, as shown in Patent Document 1, when the discharge stroke time is shortened, the pulsation is rather conspicuous in the diaphragm pump, and the prior art described in Patent Document 1 describes the cavitation in the plunger type pump. However, the present invention is not applied to a diaphragm type pump. Further, the technique disclosed in Patent Document 2 is not directly applicable to a diaphragm pump. The present invention has been made in view of the above problems, and an object of the present invention is to provide a piezoelectric diaphragm pump that can reduce pulsation of discharged fluid by changing a control method of a voltage applied to a piezoelectric element. To do.

上記目的を達成するため請求項１の発明は、平板形状の圧電素子と、前記圧電素子の一面に配された導電部材よりなる電極層と、前記圧電素子の他面を覆うように接合され、圧電素子の変形に応じて弾性変形可能な導電部材よりなるダイヤフラム板と、前記ダイヤフラム板の圧電素子が接合された面の反対面を覆うように配された絶縁層と、前記ダイヤフラム板の端部近傍を保持し、前記絶縁層の下面に気体または液体である流体を圧縮するための空間を持ち、該空間に連通して前記流体を該空間に吸入する吸入口および前記流体を該空間から吐出する吐出口とを持つ筐体と、前記電極層と前記ダイヤフラム板の間に電圧を印加することにより圧電素子を変形させて前記流体の吸入時間および吐出時間を制御する制御部とを備えた圧電ダイヤフラムポンプにおいて、前記ダイヤフラム板を、圧電素子の接合に因り、電圧を印加していない初期状態において前記空間が膨らんだ方向に湾曲しており、電圧印加により空間内の流体を吐出するように構成されており、さらに、前記制御部を、流体吸入のための電圧印加時間よりも流体吐出のための電圧印加時間が長くなるように設定したものである。   In order to achieve the above object, the invention of claim 1 is joined so as to cover a plate-shaped piezoelectric element, an electrode layer made of a conductive member disposed on one surface of the piezoelectric element, and the other surface of the piezoelectric element, A diaphragm plate made of a conductive member that can be elastically deformed in accordance with the deformation of the piezoelectric element, an insulating layer arranged to cover the opposite surface of the diaphragm plate to which the piezoelectric element is bonded, and an end of the diaphragm plate There is a space for compressing a fluid that is a gas or a liquid on the lower surface of the insulating layer, and a suction port that communicates with the space and sucks the fluid into the space, and discharges the fluid from the space. A piezoelectric diaphragm comprising: a housing having a discharge port for controlling the fluid; and a controller for controlling a suction time and a discharge time of the fluid by deforming the piezoelectric element by applying a voltage between the electrode layer and the diaphragm plate In the ram pump, the diaphragm plate is curved in a direction in which the space swells in an initial state where no voltage is applied due to bonding of the piezoelectric elements, and is configured to discharge fluid in the space by applying a voltage. Further, the control unit is set so that the voltage application time for fluid ejection is longer than the voltage application time for fluid suction.

請求項２の発明は、請求項１の発明において、前記制御部を、吐出時に印加する電圧が、積分波形の電圧となるように設定したものである。   According to a second aspect of the present invention, in the first aspect of the present invention, the control unit is set such that a voltage applied at the time of ejection is an integrated waveform voltage.

請求項３の発明は、請求項１の発明において、前記制御部を、吐出時に印加する電圧が階段状のステップ波形の電圧となるように設定したものである。   According to a third aspect of the present invention, in the first aspect of the present invention, the control unit is set such that a voltage applied at the time of ejection is a stepped step waveform voltage.

請求項４の発明は、請求項１の発明において、前記制御部を、吐出時に印加する電圧が三角波形の電圧となるように設定したものである。   According to a fourth aspect of the present invention, in the first aspect of the present invention, the control unit is set such that a voltage to be applied at the time of ejection is a triangular waveform voltage.

請求項５の発明は、請求項１の発明において、前記制御部に、ポンプの始動開始時か定常状態時かに応じ、又は流体の種類に応じて、吐出時に印加する電圧を、パルス波形と積分波形とを含む複数の波形のいずれかに切替え可能とする回路を備えたものである。   According to a fifth aspect of the present invention, in the first aspect of the present invention, the voltage applied at the time of discharge according to whether the pump is started or at a steady state, or according to the type of fluid, A circuit capable of switching to any one of a plurality of waveforms including an integrated waveform is provided.

請求項１の発明によれば、圧電ダイヤフラムポンプの流体吐出時間が長くなることから、一定の吐出流量としたとき、流体吸入のための電圧印加時間と流体吐出のための電圧印加時間が等しいときと比べて、吐出時間が長くなる分、吐出流の脈動量を低減することができる。ダイヤフラムポンプにおいては、動作周波数をプランジャ式などのポンプに比べて高くすることができるので、一回当りの吸入と吐出の流量が少なくても、時間当たりの流量は通常用途での所要量が得られ、吸入の脈動量が大きくなってもキャビテーションの発生は少ない。従って、吸入時間を吐出時間に比べ相対的に短くしても問題はない。   According to the first aspect of the present invention, since the fluid discharge time of the piezoelectric diaphragm pump becomes long, the voltage application time for fluid suction is equal to the voltage application time for fluid discharge when the discharge flow rate is constant. As compared with, the amount of pulsation of the discharge flow can be reduced by the increase of the discharge time. In diaphragm pumps, the operating frequency can be increased compared to plunger pumps, so even if the suction and discharge flow rate per stroke is small, the flow rate per hour can be as much as required for normal applications. Therefore, even if the amount of pulsation of inhalation increases, the occurrence of cavitation is small. Therefore, there is no problem even if the suction time is made relatively shorter than the discharge time.

また、圧電ダイヤフラムポンプにおいて、電圧を印加していない初期状態でダイヤフラム板はポンプ内の空間が膨らんだ方向に湾曲しており、この状態から電圧印加によりフラットに戻るように変位することで空間内の流体を吐出し、ダイヤフラム板自体の復元力で元の状態に戻るときに流体を吸入する。ここに、電圧を印加する吐出時間の方が電圧を印加しない吸入時間より長いことで、吐出側の脈動を低減することが容易となる。   Further, in the piezoelectric diaphragm pump, the diaphragm plate is bent in a direction in which the space in the pump swells in an initial state where no voltage is applied, and is displaced so as to return to a flat state by applying a voltage from this state. This fluid is discharged, and the fluid is sucked when returning to the original state by the restoring force of the diaphragm plate itself. Here, since the discharge time during which the voltage is applied is longer than the suction time during which no voltage is applied, it is easy to reduce the pulsation on the discharge side.

請求項２の発明によれば、電圧印加に対する圧電素子の変形は緩やかに起こり、流体の吐出流量は急激に増加することなく徐々に増加していくため、吐出時に矩形波形の電圧を印加したときと比べて吐出流体の脈動を小さくすることができる。   According to the second aspect of the present invention, deformation of the piezoelectric element with respect to voltage application occurs gradually, and the discharge flow rate of the fluid gradually increases without increasing rapidly. Therefore, when a rectangular waveform voltage is applied during discharge Compared with, the pulsation of the discharged fluid can be reduced.

請求項３の発明によれば、電圧印加に対して圧電素子は段階的に変形し、瞬間吐出流量は直接吐出時電圧を印加したときと比べて小さくなり、吐出流体の脈動を小さくすることができる。   According to the invention of claim 3, the piezoelectric element is deformed stepwise with respect to the voltage application, the instantaneous discharge flow rate becomes smaller than when the direct discharge voltage is applied, and the pulsation of the discharge fluid can be reduced. it can.

請求項４の発明によれば、電圧印加に対する圧電素子の変形は緩やかに起こり、瞬間吐出流量が平均的となって平均吐出流量との乖離も小さくなるので、吐出時に矩形電圧を印加したときと比べて吐出流体の脈動を小さくすることができる。   According to the fourth aspect of the present invention, the piezoelectric element is gradually deformed with respect to the voltage application, and the instantaneous discharge flow rate becomes average and the deviation from the average discharge flow rate becomes small. In comparison, the pulsation of the discharged fluid can be reduced.

請求項５の発明によれば、構造を変更することなく粘度の異なる複数の流体に対応可能となり、また、ポンプの作動開始時には流体搬送効率の良い矩形波形の電圧を印加して流体吐出までの時間を短縮させ、定常状態においては積分波形等の印加電圧を用いて脈動の少ない吐出流を得ることができ、より効率的に請求項１の発明の効果を得ることができる。   According to the invention of claim 5, it becomes possible to deal with a plurality of fluids having different viscosities without changing the structure, and at the start of the pump operation, a rectangular waveform voltage with good fluid conveyance efficiency is applied to the fluid discharge. The time can be shortened, and a discharge flow with less pulsation can be obtained using an applied voltage such as an integrated waveform in a steady state, and the effect of the invention of claim 1 can be obtained more efficiently.

以下、本発明の実施の形態に係る圧電ダイヤフラムポンプについて、図面を参照して説明する。   Hereinafter, a piezoelectric diaphragm pump according to an embodiment of the present invention will be described with reference to the drawings.

図１は、本実施の形態による圧電ダイヤフラムポンプの概略構成を示す。圧電ダイヤフラムポンプは、平板形状の圧電素子１と、圧電素子１の一面に配された導電部材よりなる電極層２と、圧電素子１の他面を覆うように接合され、圧電素子１の変形に応じて弾性変形可能な導電部材よりなるダイヤフラム板３と、ダイヤフラム板３の圧電素子１が接合された面の反対面を覆うように配された絶縁層３ａと、ダイヤフラム板３の端部近傍を保持し、絶縁層３ａの下面に気体または流体を圧縮するための空間４と、該空間４に連通した吸入口７ｃおよび吐出口７ｄとを備えた筐体５と、電極層２とダイヤフラム板３に接続された電極１０の間に電圧を印加することにより、圧電素子１を変形させて吸入・吐出時間を制御する制御部６を備える。   FIG. 1 shows a schematic configuration of a piezoelectric diaphragm pump according to the present embodiment. The piezoelectric diaphragm pump is joined so as to cover the other surface of the piezoelectric element 1 by joining the plate-shaped piezoelectric element 1, the electrode layer 2 made of a conductive member disposed on one surface of the piezoelectric element 1, and the other surface of the piezoelectric element 1. Accordingly, the diaphragm plate 3 made of a conductive member that can be elastically deformed, the insulating layer 3a disposed so as to cover the surface opposite to the surface to which the piezoelectric element 1 of the diaphragm plate 3 is bonded, and the vicinity of the end of the diaphragm plate 3 A housing 5 having a space 4 for holding and compressing a gas or a fluid on the lower surface of the insulating layer 3a, a suction port 7c and a discharge port 7d communicating with the space 4, the electrode layer 2 and the diaphragm plate 3 A control unit 6 is provided that controls the suction / discharge time by deforming the piezoelectric element 1 by applying a voltage between the electrodes 10 connected to.

本実施形態では、円形の真鍮製のダイヤフラム板３上に円形の圧電素子（ＰＺＴ）１が貼り付けられ、前記ダイヤフラム板３は、円形に成形されたプラスチック、例えばポリアセタール（ＰＯＭ）やポリカーボネイト（ＰＣ）、ポリフェニルスチレン（ＰＰＳ）等からなる筐体５に固定される。圧電素子１の寸法は、例えば直径１４ｍｍ、厚み０．１３ｍｍであり、ダイヤフラム板３は、例えば直径２０ｍｍ、厚み０．１０ｍｍの真鍮板である。   In the present embodiment, a circular piezoelectric element (PZT) 1 is attached on a circular brass diaphragm plate 3, and the diaphragm plate 3 is made of a plastic, for example, polyacetal (POM) or polycarbonate (PC). ), Polyphenylstyrene (PPS) or the like. The dimensions of the piezoelectric element 1 are, for example, a diameter of 14 mm and a thickness of 0.13 mm, and the diaphragm plate 3 is a brass plate having a diameter of 20 mm and a thickness of 0.10 mm, for example.

吸入口７ｃ、吐出口７ｄにはそれぞれ連通して吸入弁７ａ、吐出弁７ｂが接続される。これらの弁は筐体５と弁押え８との間に配置される。弁部分の構造に関しては本発明で限定するものではないが、例えば弁前後の圧力差により開閉するゴム製の片持ち弁を用いることが可能である。吸入される流体は、流体容器１２から吸入管路１１ａを経て吸入口７ｃよりポンプに吸入される。吐出される流体は、吐出口７ｄより吐出管路１１ｂを経て吐出される。   A suction valve 7a and a discharge valve 7b are connected to the suction port 7c and the discharge port 7d, respectively. These valves are arranged between the housing 5 and the valve presser 8. The structure of the valve portion is not limited in the present invention. For example, it is possible to use a rubber cantilever valve that opens and closes due to a pressure difference before and after the valve. The fluid to be sucked is sucked into the pump from the fluid container 12 through the suction pipe 11a through the suction port 7c. The fluid to be discharged is discharged from the discharge port 7d through the discharge pipe 11b.

また、本実施形態の圧電ダイヤフラムポンプの製造工程において、ダイヤフラム板３上に圧電素子１が接着（接合）されるが、このときダイヤフラム板３が熱収縮し、ダイヤフラム板３は湾曲した状態となる。圧電素子１に電圧が印加されていない初期状態においては、ダイヤフラム板３は空間４が膨らんだ方向となるように筐体５に固定される。   Further, in the manufacturing process of the piezoelectric diaphragm pump of the present embodiment, the piezoelectric element 1 is bonded (bonded) on the diaphragm plate 3. At this time, the diaphragm plate 3 is thermally contracted, and the diaphragm plate 3 is in a curved state. . In an initial state in which no voltage is applied to the piezoelectric element 1, the diaphragm plate 3 is fixed to the housing 5 so that the space 4 is in a bulging direction.

図２（ａ）（ｂ）は圧電素子１の電圧印加による変形を説明する図である。ここでは、圧電素子１の厚み方向を上下方向として示し、＋−は分極方向を示す。図１に示した電極層２とダイヤフラム板３に設けられた電極１０間に電圧を印加することで、圧電素子１の厚み方向に電界（白抜き矢印）が発生し、この電界により圧電素子１は黒矢印方向に変形する。図２（ａ）のように正電圧を印加し電界の向きが圧電素子１の分極の向きと同じ方向となるとき、圧電素子１は厚み方向に伸び、径方向に縮む。逆に、図２（ｂ）のように負電圧を印加し電界の向きが圧電素子１の分極の向きと逆方向となるとき、圧電素子１は厚み方向に縮み、径方向に伸びる。   2A and 2B are diagrams for explaining deformation of the piezoelectric element 1 due to voltage application. Here, the thickness direction of the piezoelectric element 1 is shown as the vertical direction, and + − indicates the polarization direction. By applying a voltage between the electrode layer 2 shown in FIG. 1 and the electrode 10 provided on the diaphragm plate 3, an electric field (open arrow) is generated in the thickness direction of the piezoelectric element 1. Deforms in the direction of the black arrow. When a positive voltage is applied and the direction of the electric field is the same as the direction of polarization of the piezoelectric element 1 as shown in FIG. 2A, the piezoelectric element 1 extends in the thickness direction and contracts in the radial direction. In contrast, when a negative voltage is applied and the direction of the electric field is opposite to the direction of polarization of the piezoelectric element 1 as shown in FIG. 2B, the piezoelectric element 1 contracts in the thickness direction and extends in the radial direction.

図３（ａ）（ｂ）は本実施形態による圧電ダイヤフラムポンプの動作を示す。同ダイヤフラムポンプは、図１に示したように電圧を印加していない初期状態から、正電圧を印加すると、圧電素子１は径方向に縮むが、ダイヤフラム板３は伸びないため、図３（ａ）のように圧電素子１の変形に伴ってダイヤフラム板３のたわみが減少する。これにより、絶縁層３ａと筐体５によって構成されている空間４の体積が減少して空間４内の圧力が増加し、吸入弁７ａが閉じて吐出弁７ｂが開き、吐出行程となり、吐出口７ｄより流体を吐出する。   3A and 3B show the operation of the piezoelectric diaphragm pump according to the present embodiment. In the diaphragm pump, when a positive voltage is applied from the initial state where no voltage is applied as shown in FIG. 1, the piezoelectric element 1 is contracted in the radial direction, but the diaphragm plate 3 is not expanded. As the piezoelectric element 1 is deformed, the deflection of the diaphragm plate 3 is reduced. As a result, the volume of the space 4 formed by the insulating layer 3a and the housing 5 is reduced, the pressure in the space 4 is increased, the suction valve 7a is closed, the discharge valve 7b is opened, and the discharge stroke is started. The fluid is discharged from 7d.

上記のように正電圧を印加した状態から、印加電圧を接地電圧とすると、ダイヤフラム板３は、図３（ｂ）のようにダイヤフラム板３自身の復元力によって初期状態の形状まで戻る。つまり、ダイヤフラム板３のたわみが増加することにより、空間４の体積が増加して空間４内の圧力が減少し、吐出弁７ｂが閉じて吸入弁７ａが開き、吸入行程となり、吸入口７ｃより流体を吸入する。   If the applied voltage is the ground voltage from the state where the positive voltage is applied as described above, the diaphragm plate 3 returns to the initial shape by the restoring force of the diaphragm plate 3 itself as shown in FIG. That is, as the deflection of the diaphragm plate 3 increases, the volume of the space 4 increases and the pressure in the space 4 decreases, the discharge valve 7b closes, the suction valve 7a opens, and the suction stroke starts. Inhale fluid.

ここで、印加電圧を正電圧と接地電圧の交番電圧としたとき、ダイヤフラム板３は厚み方向に振動し、ポンプは前記吐出行程と前記吸入行程を交互に繰り返す。交番電圧の周波数（駆動周波数）が低い時には、吐出のための電圧を印加したとき、圧電素子１が急激に変形するため、吐出される流体は電圧の印加直後が最も流量が多く、吐出によりポンプ内部の流体が減少することにより瞬間の流量は徐々に減少していき、ほぼ零に収束する。その後、印加電圧が接地電圧となると、吸入行程が始まり、吐出行程と同様に、流体の瞬間吸入量は印加電圧を接地電圧とした瞬間がもっとも大きく、その後、徐々に減少していく。   Here, when the applied voltage is an alternating voltage of a positive voltage and a ground voltage, the diaphragm plate 3 vibrates in the thickness direction, and the pump repeats the discharge stroke and the suction stroke alternately. When the frequency of the alternating voltage (driving frequency) is low, the piezoelectric element 1 deforms abruptly when a voltage for ejection is applied. Therefore, the fluid to be ejected has the highest flow rate immediately after application of the voltage, and the pump is pumped by ejection. As the internal fluid decreases, the instantaneous flow rate gradually decreases and converges to almost zero. Thereafter, when the applied voltage becomes the ground voltage, the suction stroke starts, and the instantaneous suction amount of the fluid is greatest at the moment when the applied voltage is the ground voltage, and then gradually decreases, as in the discharge stroke.

駆動周波数を増加させていくと、瞬間の吸入流量または吐出流量が減少して零となった瞬間に逆方向の電圧が印加される状態となる。この場合がポンプを流れる流体の流量が最も大きくなる。被駆動流体が水である場合、駆動周波数が約４０Ｈｚで最も流体流量が大きくなる。駆動周波数を上記より高くすると、吐出行程において瞬間の吐出流量が零となる前に吸入行程に移る。このとき、ポンプを流れる流体の流量は、上記の場合よりも減少し、印加した電圧により期待される流量は確保されない。   When the drive frequency is increased, a reverse voltage is applied at the moment when the instantaneous suction flow rate or discharge flow rate decreases to zero. In this case, the flow rate of the fluid flowing through the pump becomes the largest. When the driven fluid is water, the fluid flow rate becomes the highest at a driving frequency of about 40 Hz. If the drive frequency is higher than the above, the suction stroke starts before the instantaneous discharge flow rate becomes zero in the discharge stroke. At this time, the flow rate of the fluid flowing through the pump is smaller than in the above case, and the flow rate expected by the applied voltage is not ensured.

次に、圧電素子１に印加する電圧波形の例について、図４〜図７を参照して説明する。   Next, examples of voltage waveforms applied to the piezoelectric element 1 will be described with reference to FIGS.

図４は、請求項１の発明に係る実施例１における印加電圧の波形と、同時刻でのポンプを流れる流体の流量を模式的に示す。本実施例では、印加電圧は＋１２０Ｖと０Ｖの交番電圧とし、図４に実線にて示されるようなＤｕｔｙ比（正電圧印加時間比）が７０％とした電圧を用いる。図４において時刻ｔ１に＋１２０Ｖの電圧を印加したときにポンプは吐出行程を開始し、時刻ｔ３に０Ｖの電圧を印加した時にポンプは吸入行程を開始する。印加する交番電圧の周波数を１００Ｈｚとすると、図４の時刻ｔ３から時刻ｔ４に示される吸入電圧印加時間は３ｍｓとなる。時刻ｔ１から時刻ｔ３に示される吐出電圧（０Ｖ）印加時間は７ｍｓであり、この時間で完全に吐出が終了するような条件を設定することで、ポンプの平均流量が最も大きくなるため、最大流量と平均流量との差が最も小さくなり吐出流の脈動を小さくすることができる。   FIG. 4 schematically shows the waveform of the applied voltage in Example 1 according to the invention of claim 1 and the flow rate of the fluid flowing through the pump at the same time. In this embodiment, the applied voltage is an alternating voltage of +120 V and 0 V, and a voltage with a duty ratio (positive voltage application time ratio) of 70% as shown by a solid line in FIG. 4 is used. In FIG. 4, the pump starts the discharge stroke when a voltage of +120 V is applied at time t1, and the pump starts the suction stroke when a voltage of 0 V is applied at time t3. When the frequency of the alternating voltage to be applied is 100 Hz, the suction voltage application time shown from time t3 to time t4 in FIG. 4 is 3 ms. The discharge voltage (0V) application time shown from time t1 to time t3 is 7 ms. By setting conditions such that discharge is completely completed within this time, the average flow rate of the pump becomes the largest, so the maximum flow rate And the average flow rate becomes the smallest, and the pulsation of the discharge flow can be reduced.

このための条件は、例えば吐出側の流路抵抗を吸入側よりも大きくして、流体を完全に吐出するのに要する時間を電圧の印加時間と一致させ、また吸入側の流路抵抗を小さくし、吸入に要する時間を電圧の印加時間と一致させることで設定できる。このとき、吸入流量波形は図４の実線のようになり、時刻ｔ３に最大となる瞬間吸入流量は、破線にて示したようなＤｕｔｙ比が５０％のときの、時刻ｔ２に最大となる瞬間吸入流量と比較して大きくなるが、この吸入側の脈動は吐出側の脈動には影響しない。また、ダイヤフラムポンプにおいては、動作周波数をプランジャ式などのポンプに比べて高くすることができるので、一回当りの吸入と吐出の流量が少なくても、時間当たりの流量は、例えば液体噴霧装置などに液体を供給するなど、通常の用途での所要量が得られ、吸入の脈動量が大きくなってもキャビテーションの発生は少ない。したがって、吸入時間を吐出時間に比べ相対的に短くしても問題はない。   The condition for this is, for example, that the flow path resistance on the discharge side is made larger than that on the suction side so that the time required to completely discharge the fluid coincides with the voltage application time, and the flow path resistance on the suction side is reduced. The time required for inhalation can be set to coincide with the voltage application time. At this time, the suction flow waveform is as shown by the solid line in FIG. 4, and the instantaneous suction flow that becomes maximum at time t3 is the maximum at time t2 when the duty ratio is 50% as shown by the broken line. Although larger than the suction flow rate, the suction side pulsation does not affect the discharge side pulsation. Moreover, in the diaphragm pump, since the operating frequency can be made higher than that of a plunger type pump, even if the suction and discharge flow rate per time is small, the flow rate per time is, for example, a liquid spray device, etc. The required amount for normal use such as supplying liquid to the tube can be obtained, and even if the amount of pulsation of inhalation increases, the occurrence of cavitation is small. Therefore, there is no problem even if the suction time is made relatively shorter than the discharge time.

図５は、請求項２の発明に係る実施例２における印加電圧の波形と、同時刻でのポンプを流れる流体の流量を模式的に示す。本実施例では、印加電圧は＋１２０Ｖと０Ｖの交番電圧とし、図５に実線で示されたような積分波形の電圧とする。このような波形は、例えば電圧印加時に高電圧と圧電素子電極の中間に適切な抵抗を挿入するか、あるいはトランジスタにより印加電圧をコントロールすることにより実現可能であるが、実現手段はこれに限定されない。矩形波形の印加電圧を用いると、吐出直後の瞬間流量が大きくなる問題があったが、本実施例では図５の実線に示されるように、時刻ｔ１から時刻ｔ３まで吐出時に印加する電圧が連続的に増加することにより、電圧印加に対する圧電素子の変形は緩やかに起こるため、吐出流量は急激に増加することなく徐々に増加する。時刻ｔ３から時刻ｔ４の間は吸入電圧印加時間である。こうして、矩形波形の印加電圧を用いたときより瞬間吐出流量の最大値が小さくなるため、吐出流の脈動が小さくなる。また、吐出電圧を印加する時間割合が大きいため、最終的な吐出流量は、矩形電圧を印加するときと同等の流量が得られる。   FIG. 5 schematically shows the waveform of the applied voltage in Example 2 according to the invention of claim 2 and the flow rate of the fluid flowing through the pump at the same time. In this embodiment, the applied voltage is an alternating voltage of +120 V and 0 V, and is an integrated waveform voltage as shown by a solid line in FIG. Such a waveform can be realized, for example, by inserting an appropriate resistance between the high voltage and the piezoelectric element electrode during voltage application, or by controlling the applied voltage with a transistor, but the implementation means is not limited to this. . When the application voltage having a rectangular waveform is used, there is a problem that the instantaneous flow rate immediately after the discharge becomes large, but in this embodiment, as shown by the solid line in FIG. 5, the voltage applied during the discharge from time t1 to time t3 is continuous. Therefore, the piezoelectric element is gradually deformed with respect to voltage application, so that the discharge flow rate gradually increases without increasing rapidly. The period from time t3 to time t4 is the suction voltage application time. Thus, since the maximum value of the instantaneous discharge flow rate is smaller than when the applied voltage having the rectangular waveform is used, the pulsation of the discharge flow is reduced. Moreover, since the time ratio during which the discharge voltage is applied is large, the final discharge flow rate is the same as that when the rectangular voltage is applied.

図６は、請求項３の発明に係る実施例３における印加電圧の波形と、同時刻でのポンプを流れる流体の流量を示す。本実施例において、吸入時電圧を０Ｖ、吐出時電圧を＋１２０Ｖに定める。図６の時刻ｔ１以前の印加電圧が０Ｖである状態において、時刻ｔ１より、吸入時電圧と吐出時電圧の中間の電圧として＋６０Ｖを印加した後、時刻ｔ２より印加電圧を＋１２０Ｖまで上昇させる。つまり、吐出時に段階上のステップ波形の電圧を印加する。時刻ｔ１における圧電素子１の初期状態からの変形量は、時刻ｔ１に＋１２０Ｖの電圧を印加したときより小さくなるため、図６の実線で示されるように、瞬間的な吐出流量は＋１２０Ｖを印加したときより少なくなる。この定常状態を時刻ｔ１から時刻ｔ２まで一定時間維持することで、瞬間の流量はこの時間徐々に減少する。その後、時刻ｔ２から＋１２０Ｖを印加したときの圧電素子１の変形は、＋６０Ｖ印加時の状態からの変形量となるため、やはり瞬間吐出流量は０Ｖから直ぐに＋１２０Ｖを印加するときよりも小さくなる。これらの結果として、吸入時電圧と吐出時電圧の間の電位を、吐出行程中に挿入することで、矩形波形の印加電圧を用いたときより瞬間吐出流量の最大値が小さくなるため、吐出流体の脈動は減少することになる。   FIG. 6 shows the waveform of the applied voltage in Example 3 according to the invention of claim 3 and the flow rate of the fluid flowing through the pump at the same time. In this embodiment, the suction voltage is set to 0V and the discharge voltage is set to + 120V. In a state where the applied voltage before time t1 in FIG. 6 is 0V, + 60V is applied as an intermediate voltage between the suction voltage and the discharge voltage from time t1, and then the applied voltage is increased to + 120V from time t2. That is, a stepped waveform voltage is applied during ejection. Since the deformation amount from the initial state of the piezoelectric element 1 at time t1 is smaller than when a voltage of +120 V is applied at time t1, as shown by the solid line in FIG. 6, an instantaneous discharge flow rate of +120 V was applied. Less than when. By maintaining this steady state for a certain period of time from time t1 to time t2, the instantaneous flow rate gradually decreases during this time. After that, the deformation of the piezoelectric element 1 when +120 V is applied from time t2 becomes the deformation amount from the state when +60 V is applied, so that the instantaneous discharge flow rate is also smaller than when +120 V is applied immediately from 0 V. As a result, by inserting a potential between the suction voltage and the discharge voltage during the discharge stroke, the maximum value of the instantaneous discharge flow rate becomes smaller than when the applied voltage having a rectangular waveform is used. The pulsation will decrease.

図７は、請求項４の発明に係る実施例４における印加電圧の波形と、同時刻でのポンプを流れる流体の流量を模式的に示す。本実施例において、印加電圧は＋１２０Ｖと０Ｖの交番電圧とし、図７に実線で示されたような三角波形の電圧とする。このような波形は、例えばトランジスタまたはオペアンプにより電圧の増幅を行うことによって実現可能であるが、実現手段はこれに限定されない。吐出時に矩形波形の電圧を印加したときには、吐出直後の瞬間吐出流量が大きい問題があったが、時刻ｔ１からｔ２まで吐出時に印加する電圧の上昇を一定割合にすることで、圧電素子１は緩やかに変形するので、瞬間吐出流量を平均的にすることができ、平均流量との乖離も小さくなる。つまり、矩形波形の印加電圧を用いたときより瞬間吐出流量の最大値が小さくなるため、吐出流の脈動が小さくなる。また、吐出電圧を印加する時間割合が大きいため、最終的な吐出流量は、矩形電圧を印加するときと同等の流量が得られる。   FIG. 7 schematically shows the waveform of the applied voltage in Example 4 according to the invention of claim 4 and the flow rate of the fluid flowing through the pump at the same time. In this embodiment, the applied voltage is an alternating voltage of +120 V and 0 V, and is a triangular waveform voltage as shown by the solid line in FIG. Such a waveform can be realized, for example, by amplifying the voltage with a transistor or an operational amplifier, but the realization means is not limited to this. When a voltage having a rectangular waveform is applied during discharge, there is a problem that the instantaneous discharge flow rate immediately after discharge is large. However, by increasing the voltage applied during discharge from time t1 to t2, the piezoelectric element 1 is moderated. Therefore, the instantaneous discharge flow rate can be averaged, and the deviation from the average flow rate is also reduced. That is, since the maximum value of the instantaneous discharge flow rate is smaller than when a rectangular waveform applied voltage is used, the pulsation of the discharge flow is reduced. Moreover, since the time ratio during which the discharge voltage is applied is large, the final discharge flow rate is the same as that when the rectangular voltage is applied.

図８は、請求項５の発明に係る実施例５における回路図と、印加電圧の波形を模式的に示す。本実施例では、印加電圧の波形として、図８（ｂ）のような矩形波形と、図８（ｃ）のような積分波形を切替え可能な制御部６を持つ。この制御部６は、図８（ａ）に例示されるように、抵抗Ｒが挿入された経路（Ｙ）と挿入されていない経路（Ｘ）を切替えるスイッチＳＷと、このスイッチＳＷと電圧印加時間を制御する部位（Ｚ）とを備える。矩形波形の電圧を印加するとき、一般に流体の脈動は大きいが流量は大きい。これに対して、積分波形の電圧を印加したときは、流量は小さいが脈動は小さくなる。このことから、ポンプの始動開始時に吐出口７ｄの先端まで流体を送るときは、吐出流への脈動の影響はないため、図８（ｂ）に示した吸入効率の高い矩形波形の印加電圧で作動させて、吐出口７ｄから流体が吐出し始めた後（定常状態）は、図８（ｃ）に示した積分波形の印加電圧に切替えることで、定常状態において吐出流の脈動の低減が実現できる。   FIG. 8 schematically shows a circuit diagram and a waveform of an applied voltage in the fifth embodiment according to the invention of claim 5. In the present embodiment, as the waveform of the applied voltage, the control unit 6 that can switch between a rectangular waveform as shown in FIG. 8B and an integrated waveform as shown in FIG. 8C is provided. As illustrated in FIG. 8A, the control unit 6 includes a switch SW that switches a path (Y) in which the resistor R is inserted and a path (X) in which the resistor R is not inserted, and the switch SW and the voltage application time. And a part (Z) for controlling the. When a voltage having a rectangular waveform is applied, fluid pulsation is generally large but flow rate is large. On the other hand, when an integral waveform voltage is applied, the flow rate is small but the pulsation is small. Therefore, when the fluid is sent to the tip of the discharge port 7d at the start of the pump start, there is no influence of the pulsation on the discharge flow, so the applied voltage of the rectangular waveform having a high suction efficiency shown in FIG. After the operation and the fluid starts to be discharged from the discharge port 7d (steady state), the pulsation of the discharge flow is reduced in the steady state by switching to the applied voltage of the integral waveform shown in FIG. 8C. it can.

図９には、請求項５の発明に係る、実施例６における回路図と、印加電圧の波形を模式的に示す。本実施例では、印加電圧の波形として、図９（ｂ）のような電圧上昇速度が高い積分波形と、図９（ｃ）のような電圧上昇速度が低い積分波形を切替え可能な制御部６を持つ。この制御部６は、図９（ａ）に例示されるように、抵抗Ｒが挿入された経路（Ｘ）と２つの抵抗Ｒが挿入された経路（Ｙ）を切替えるスイッチＳＷと、このスイッチＳＷと電圧印加時間を制御する部位（Ｚ）とを備える。このような構成によれば、ポンプを、粘度の異なる流体として、例えば油（粘度０．０２）と水（粘度０．００１Ｐａ・ｓ）とを吐出する用途に用いる場合、粘度が２０倍異なるため、同一の電圧波形で制御すると、流量は油と水で異なるが、スイッチＳＷを切替えて、流体の粘度に合った積分波形の電圧上昇速度に変更することで、ポンプの流路径などの構造を変更することなく複数の流体の種類に対応することが可能となる。なお、図９（ｂ）は油用電圧波形であり、（ｃ）は水用電圧波形である。   FIG. 9 schematically shows a circuit diagram and a waveform of an applied voltage in Example 6 according to the invention of claim 5. In the present embodiment, as the waveform of the applied voltage, the control unit 6 capable of switching between an integrated waveform with a high voltage rising speed as shown in FIG. 9B and an integrated waveform with a low voltage rising speed as shown in FIG. 9C. have. As illustrated in FIG. 9A, the control unit 6 includes a switch SW that switches a path (X) in which the resistor R is inserted and a path (Y) in which the two resistors R are inserted, and the switch SW. And a portion (Z) for controlling the voltage application time. According to such a configuration, when the pump is used as a fluid having different viscosities, for example, for discharging oil (viscosity 0.02) and water (viscosity 0.001 Pa · s), the viscosities differ by 20 times. When controlled with the same voltage waveform, the flow rate differs between oil and water, but by switching the switch SW and changing to the voltage rise rate of the integral waveform that matches the viscosity of the fluid, the structure such as the flow path diameter of the pump It becomes possible to cope with a plurality of types of fluids without changing. In addition, FIG.9 (b) is a voltage waveform for oil, (c) is a voltage waveform for water.

図１０は、実施例７による圧電ダイヤフラムポンプの概略構成を示す。実施例７は、上記実施例１〜実施例４において、吐出管路１１ｂの吐出口７ｄの近傍にポンプからの吐出流量の変動を測定するための流量センサ１３を配設し、制御部６によって流量センサ１３からの値を基に吸入の電圧印加時間と吐出の電圧印加時間をフィードバック制御するものである。その他の構成は図１に示したものと同等である。   FIG. 10 shows a schematic configuration of the piezoelectric diaphragm pump according to the seventh embodiment. In the seventh embodiment, the flow rate sensor 13 for measuring the fluctuation of the discharge flow rate from the pump is arranged in the vicinity of the discharge port 7d of the discharge pipe 11b in the first to fourth embodiments. The suction voltage application time and the discharge voltage application time are feedback-controlled based on the value from the flow sensor 13. Other configurations are the same as those shown in FIG.

本実施例において、流量センサ１３より計測された流量値が設定値よりも大きくなったとき、制御部６は吸入の電圧印加時間を短くすることにより、総流量を減少させる。また、流量が設定値よりも小さいとき、制御部６は吸入の電圧印加時間を長くすることで、総流量を増加させる。吸入と吐出の電圧印加時間比率は任意に変更可能であるが、吐出流の脈動を低減するためには吐出の印加電圧の時間割合が大きい範囲に設定しておくことが望ましい。このように、吐出流量を計測しながら吸入と吐出の電圧印加時間比率をフィードバック制御するので、吐出流の脈動を小さくしながら、安定した設定流量を確保することが可能となり、吸入の電圧印加時間が不足して流体が完全に吸入できないことによる流量の低下を防止することができる。   In this embodiment, when the flow rate value measured by the flow rate sensor 13 becomes larger than the set value, the control unit 6 decreases the total flow rate by shortening the suction voltage application time. When the flow rate is smaller than the set value, the control unit 6 increases the total flow rate by extending the voltage application time for suction. Although the voltage application time ratio of suction and discharge can be arbitrarily changed, it is desirable to set the time ratio of the discharge application voltage in a large range in order to reduce the pulsation of the discharge flow. In this way, since the suction and discharge voltage application time ratio is feedback controlled while measuring the discharge flow rate, it becomes possible to secure a stable set flow rate while reducing the pulsation of the discharge flow, and the suction voltage application time Therefore, it is possible to prevent a decrease in the flow rate due to the fact that the fluid cannot be completely sucked due to the shortage of the fluid.

図１１は、実施例８による圧電ダイヤフラムポンプの概略構成を示す。実施例８は、上記実施例１〜実施例４において、吸入管路１１ａの吸入口７ｃの近傍に流体容器１２からの吸入流量の変動を測定するための流量センサ１４を配設し、制御部６によって流量センサ１４の値を基に吸入の電圧印加時間をフィードバック制御するものである。その他の構成は図１に示したものと同等である。   FIG. 11 shows a schematic configuration of the piezoelectric diaphragm pump according to the eighth embodiment. In the eighth embodiment, the flow rate sensor 14 for measuring the fluctuation of the suction flow rate from the fluid container 12 is disposed in the vicinity of the suction port 7c of the suction pipe 11a in the first to fourth embodiments, and the control unit 6, feedback control of the suction voltage application time is performed based on the value of the flow sensor 14. Other configurations are the same as those shown in FIG.

本実施例において、流量センサ１４により計測された流量値が設定値よりも大きくなったとき、制御部６は吸入の電圧印加時間を短くすることにより、総流量を減少させる。また、流量が設定値よりも小さいとき、制御部６は吸入の電圧印加時間を長くすることで、総流量を増加させる。この制御は予め最適化された吐出流量の脈動低減の条件には影響しない。吐出流の脈動を低減するには、吸入と吐出の電圧印加時間比率は、実施例７と同様に設定しておくことが望ましい。このように、吸入流量を計測しながら電圧印加時間をフィードバック制御するので、吸入の電圧印加時間が不足して流体が完全に吸入できないことによる流量の低下を防止することができる。また、吐出流量の脈動を低減した最適化条件を変更することなく、吸入量（吐出量）の確保が可能となる。   In the present embodiment, when the flow rate value measured by the flow rate sensor 14 becomes larger than the set value, the control unit 6 decreases the total flow rate by shortening the suction voltage application time. When the flow rate is smaller than the set value, the control unit 6 increases the total flow rate by extending the voltage application time for suction. This control does not affect the pre-optimized discharge flow pulsation reduction conditions. In order to reduce the pulsation of the discharge flow, it is desirable to set the voltage application time ratio between suction and discharge in the same manner as in the seventh embodiment. As described above, since the voltage application time is feedback-controlled while measuring the suction flow rate, it is possible to prevent a decrease in the flow rate due to the shortage of the suction voltage application time and the inability to completely suck the fluid. In addition, it is possible to secure the suction amount (discharge amount) without changing the optimization condition for reducing the pulsation of the discharge flow rate.

図１２及び図１３は、実施例９における印加電圧の波形を模式的に示す。本実施例は、上記実施例８の構成において、制御部６にて流量センサ１４からの最大流量値を基に、図１２及び図１３に示したような定常電圧の領域を含んだ積分波形の印加電圧の、定常電圧である時間をフィードバック制御するものである。図１２は定常電圧時間を短くしたとき、図１３は定常電圧時間を長くしたときを示す。いずれも、時刻ｔ１から時刻ｔ３までが吐出の電圧印加時間であり、時刻ｔ３から時刻ｔ４までが吸入の電圧印加時間であり、吸入時電圧を０Ｖ、吐出時電圧を＋１２０Ｖに定め、吸入時電圧と吐出時電圧の中間の定常電圧として＋６０Ｖを設定し、時刻ｔ１より積分波形で電圧を上昇させ、時刻ｔ2-1 より所定時間後の時刻ｔ2-2 まで印加電圧＋６０Ｖの定常状態とし、時刻ｔ2-2 より再び積分波形にて＋１２０Ｖまで印加電圧を上昇させる。   12 and 13 schematically show the waveform of the applied voltage in Example 9. FIG. In the present embodiment, in the configuration of the above-described eighth embodiment, an integrated waveform including a steady voltage region as shown in FIGS. 12 and 13 is based on the maximum flow rate value from the flow rate sensor 14 in the control unit 6. Feedback control is performed on the time during which the applied voltage is a steady voltage. FIG. 12 shows a case where the steady voltage time is shortened, and FIG. 13 shows a case where the steady voltage time is lengthened. In any case, the discharge voltage application time is from time t1 to time t3, the suction voltage application time is from time t3 to time t4, the suction voltage is set to 0V, the discharge voltage is set to + 120V, and the suction voltage is set. + 60V is set as a steady voltage intermediate between the discharge voltage and the discharge voltage, the voltage is increased with an integrated waveform from time t1, and the applied voltage + 60V is steady until a time t2-2 a predetermined time after time t2-1. From -2, increase the applied voltage to + 120V again with the integrated waveform.

本実施例において、流量センサ１４によって測定された瞬間流量の最大値が設定値よりも大きくなったときには、図１３に示すように、制御部６により時刻ｔ2-1 から時刻ｔ2-2 までの定常電圧の印加時間を長くすることにより、ポンプの総流量を減少させることができ、逆に、流量の最大値が設定値よりも小さくなったときには、図１２に示すように定常電圧の印加時間を短くすることにより、流量を増加させることができる。この定常電圧印加時間を制御することによる流量調整は、脈動低減のための条件とは独立して設定可能であり、最適な吐出条件を維持したまま安定して設定流量を確保することができる。また、吸入時電圧と吐出時電圧の中間の電位を吐出行程の間に挿入し、また積分波形で電圧を印加しているので、実施例３と同様に脈流低減効果が得られるとともに、圧電素子が段階的に、緩やかに変形するため、圧電素子が過変形することを防ぐことができる。   In this embodiment, when the maximum value of the instantaneous flow rate measured by the flow rate sensor 14 becomes larger than the set value, the control unit 6 makes a steady state from time t2-1 to time t2-2 as shown in FIG. By increasing the voltage application time, the total flow rate of the pump can be reduced. Conversely, when the maximum value of the flow rate becomes smaller than the set value, the application time of the steady voltage is reduced as shown in FIG. By shortening, the flow rate can be increased. The flow rate adjustment by controlling the steady voltage application time can be set independently of the conditions for reducing the pulsation, and the set flow rate can be secured stably while maintaining the optimum discharge conditions. In addition, since an intermediate potential between the suction voltage and the discharge voltage is inserted between the discharge strokes, and the voltage is applied with an integral waveform, the pulsating flow reducing effect can be obtained as in the third embodiment, and the piezoelectric Since the element is gradually deformed step by step, the piezoelectric element can be prevented from being excessively deformed.

なお、本発明は上記実施形態の構成に限定するものではなく、発明の範囲を変更しない範囲で適宜に種々の変形が可能である。例えば、吸入のために印加する電圧を負電圧としてもよい。また、圧電素子の分極の向きが逆である場合も、圧電素子に印加する電圧を負電圧とする、あるいは圧電素子に電圧を印加する向きを逆にすることでまったく同等の動作を実現できる。   In addition, this invention is not limited to the structure of the said embodiment, A various deformation | transformation is suitably possible in the range which does not change the scope of the invention. For example, the voltage applied for inhalation may be a negative voltage. In addition, even when the direction of polarization of the piezoelectric element is reversed, a completely equivalent operation can be realized by setting the voltage applied to the piezoelectric element to a negative voltage or reversing the direction of applying the voltage to the piezoelectric element.

本発明の実施の形態による圧電ダイヤフラムポンプの概略構成を示す図。The figure which shows schematic structure of the piezoelectric diaphragm pump by embodiment of this invention. （ａ）は同上圧電ダイヤフラムポンプに用いられる圧電素子に正電圧を印加したときの動作を示す図、（ｂ）は同圧電素子に負電圧を印加した時の動作を示す図。(A) is a figure which shows operation | movement when a positive voltage is applied to the piezoelectric element used for a piezoelectric diaphragm pump same as the above, (b) is a figure which shows operation | movement when a negative voltage is applied to the piezoelectric element. 本発明の実施の形態による圧電ダイヤフラムポンプの動作を示す図であり、（ａ）は吐出の電圧を印加した状態を示す図、（ｂ）は吸入の電圧を印加した状態を示す図。It is a figure which shows operation | movement of the piezoelectric diaphragm pump by embodiment of this invention, (a) is a figure which shows the state which applied the voltage of discharge, (b) is a figure which shows the state which applied the voltage of inhalation. 実施例１に係る圧電ダイヤフラムポンプの制御を説明する図。FIG. 3 is a diagram for explaining control of the piezoelectric diaphragm pump according to the first embodiment. 実施例２に係る圧電ダイヤフラムポンプの制御を説明する図。FIG. 6 is a diagram for explaining control of a piezoelectric diaphragm pump according to a second embodiment. 実施例３に係る圧電ダイヤフラムポンプの制御を説明する図。FIG. 6 is a diagram for explaining control of a piezoelectric diaphragm pump according to a third embodiment. 実施例４に係る圧電ダイヤフラムポンプの制御を説明する図。FIG. 6 is a diagram for explaining control of a piezoelectric diaphragm pump according to a fourth embodiment. （ａ）は実施例５に係る圧電ダイヤフラムポンプの制御のための回路図、（ｂ）、（ｃ）は制御を説明する図。(A) is a circuit diagram for controlling the piezoelectric diaphragm pump according to the fifth embodiment, and (b) and (c) are diagrams for explaining the control. （ａ）は実施例６に係る圧電ダイヤフラムポンプの制御のための回路図、（ｂ）、（ｃ）は制御を説明する図。(A) is a circuit diagram for controlling the piezoelectric diaphragm pump according to the sixth embodiment, and (b) and (c) are diagrams for explaining the control. 実施例７に係る圧電ダイヤフラムポンプの概略構成を示す図。FIG. 10 is a diagram illustrating a schematic configuration of a piezoelectric diaphragm pump according to a seventh embodiment. 実施例８に係る圧電ダイヤフラムポンプの概略構成を示す図。FIG. 10 is a diagram illustrating a schematic configuration of a piezoelectric diaphragm pump according to an eighth embodiment. 実施例９に係る圧電ダイヤフラムポンプの制御を説明する図。FIG. 10 is a diagram for explaining control of a piezoelectric diaphragm pump according to a ninth embodiment. 同上の圧電ダイヤフラムポンプの制御を説明する図。The figure explaining control of a piezoelectric diaphragm pump same as the above.

符号の説明Explanation of symbols

１ 圧電素子
２ 電極層
３ ダイヤフラム板
３ａ 絶縁層
４ 空間
５ 筐体
６ 制御部
７ｃ 吸入口
７ｄ 吐出口
DESCRIPTION OF SYMBOLS 1 Piezoelectric element 2 Electrode layer 3 Diaphragm plate 3a Insulating layer 4 Space 5 Case 6 Control part 7c Inlet 7d Inlet

Claims (5)

平板形状の圧電素子と、前記圧電素子の一面に配された導電部材よりなる電極層と、前記圧電素子の他面を覆うように接合され、圧電素子の変形に応じて弾性変形可能な導電部材よりなるダイヤフラム板と、前記ダイヤフラム板の圧電素子が接合された面の反対面を覆うように配された絶縁層と、前記ダイヤフラム板の端部近傍を保持し、前記絶縁層の下面に気体または液体でなる流体を圧縮するための空間を持ち、該空間に連通して前記流体を該空間に吸入する吸入口および前記流体を該空間から吐出する吐出口とを持つ筐体と、前記電極層と前記ダイヤフラム板の間に電圧を印加することにより圧電素子を変形させて前記流体の吸入時間および吐出時間を制御する制御部とを備えた圧電ダイヤフラムポンプにおいて、
前記ダイヤフラム板は、圧電素子の接合に因り、電圧を印加していない初期状態において前記空間が膨らんだ方向に湾曲しており、電圧印加により空間内の流体を吐出するように構成されており、
前記制御部は、流体吸入のための電圧印加時間よりも流体吐出のための電圧印加時間が長くなるように設定されていることを特徴とする圧電ダイヤフラムポンプ。 A flat plate-shaped piezoelectric element, an electrode layer made of a conductive member disposed on one surface of the piezoelectric element, and a conductive member bonded so as to cover the other surface of the piezoelectric element and elastically deformable according to the deformation of the piezoelectric element A diaphragm plate, an insulating layer disposed so as to cover a surface opposite to a surface to which the piezoelectric element of the diaphragm plate is bonded, and a vicinity of an end portion of the diaphragm plate, and a gas or A housing having a space for compressing a fluid made of a liquid, a suction port that communicates with the space and sucks the fluid into the space, and a discharge port that discharges the fluid from the space; and the electrode layer A piezoelectric diaphragm pump comprising: a control unit for controlling the suction time and the discharge time of the fluid by deforming the piezoelectric element by applying a voltage between the diaphragm plate and the diaphragm plate;
The diaphragm plate is curved in a direction in which the space swells in an initial state where no voltage is applied due to bonding of the piezoelectric elements, and is configured to discharge a fluid in the space by applying a voltage.
The piezoelectric diaphragm pump characterized in that the control unit is set so that a voltage application time for fluid ejection is longer than a voltage application time for fluid suction. 前記制御部は、吐出時に印加する電圧が積分波形の電圧に設定されていることを特徴とする請求項１記載の圧電ダイヤフラムポンプ。   2. The piezoelectric diaphragm pump according to claim 1, wherein the control unit is configured such that a voltage to be applied at the time of discharge is set to an integral waveform voltage. 前記制御部は、吐出時に印加する電圧が階段状のステップ波形の電圧に設定されていることを特徴とする請求項１記載の圧電ダイヤフラムポンプ。   2. The piezoelectric diaphragm pump according to claim 1, wherein the control unit is configured such that a voltage to be applied at the time of discharge is set to a voltage having a stepped step waveform. 前記制御部は、吐出時に印加する電圧が三角波形の電圧に設定されていることを特徴とする請求項１記載の圧電ダイヤフラムポンプ。   2. The piezoelectric diaphragm pump according to claim 1, wherein the controller applies a voltage applied at the time of discharge to a triangular waveform voltage. 前記制御部は、ポンプの始動開始時か定常状態時かに応じ、又は流体の種類に応じて、吐出時に印加する電圧を、パルス波形と積分波形とを含む複数の波形のいずれかに切替え可能とする回路を備えたことを特徴とする請求項１記載の圧電ダイヤフラムポンプ。
The control unit can switch the voltage applied at the time of discharge to one of a plurality of waveforms including a pulse waveform and an integrated waveform, depending on whether the pump starts or is in a steady state, or depending on the type of fluid The piezoelectric diaphragm pump according to claim 1, further comprising:
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