JP2002130137A - Piezoelectric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric pump preventing the leakage of liquid from a pump chamber. SOLUTION: In the piezoelectric pump 1, an inner plate 13 having check valves 11 and 12 and a cartridge 5 with a piezoelectric vibrator 14 affixed thereto are assembled in an overlapping relationship and incorporated into a pump body 2 and the space between the inner plate 13 and the cartridge 15 is used as the pump chamber 18. The cartridge 15 comprises a bottom surface vibrating portion 15B with the piezoelectric vibrator 14 affixed thereto, and a thick-walled, cylindrical guide portion 15A located at the peripheral edge of the vibrating portion and pressed against the inner plate 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric pump for sucking, pumping and conveying a liquid by vibrating a piezoelectric vibrator, and more particularly to a piezoelectric pump for preventing liquid leakage to the piezoelectric vibrator side.

[0002]

2. Description of the Related Art Conventionally, a piezoelectric pump for sucking, pumping and conveying a liquid by vibrating a piezoelectric vibrator has a structure as shown in FIG. FIG. 4 is a sectional view showing a conventional piezoelectric pump. The piezoelectric pump 100 has a pump body 10 having an input port 101 and an output port 102 formed therein.
3 is fitted with an inner plate 104 having a concave cross section.
The diaphragm 106 with the adhesive 05 is fitted into the pump chamber 1
07. The vibrating plate 106 has its peripheral edge pressed down by a lid 109 with a sealing O-ring 108 interposed therebetween to prevent liquid leakage in the pump chamber 107.

In the piezoelectric pump 100, a pump chamber 107 is formed to have a variable volume by a vibration plate 106, and an input side valve hole 113 and an output side valve hole are connected so that a primary side flow path 111 and an output port 112 communicate with each other. 114 are formed. A check valve 115 is attached to the input side valve hole 113 with the head portion facing the pump chamber 107, and a check valve 116 is connected to the output side valve hole 114 with the head portion facing the output port 102. Attached, the liquid entering from the input port 101 is configured to flow to the output port 102 through the pump chamber 107 without backflow.

Therefore, such a piezoelectric pump is provided with a vibration plate 106 due to distortion of a piezoelectric vibrator 105 to which a voltage is applied.
When flexing and vibrating, the volume in the pump chamber 107 changes, and the liquid is transported by the pump operation. Specifically, when the pump chamber 107 is widened and the pressure is low,
The liquid is sucked into the pump chamber 107 by bending the check valve 115 from the input port 101, and then, when the pump chamber 107 becomes narrow and the pressure increases, the liquid in the pump chamber 107 is pressurized and the check valve 116 is released. Is bent and discharged to the output port 102 to be conveyed.

[0005]

However, in such a conventional piezoelectric pump, a pump chamber 1 for performing a pump operation is provided.
There is a problem that the liquid pressurized in 07 leaks to the opposite side around the vibrating plate 106, causing corrosion of the piezoelectric vibrator touching the liquid or causing dielectric breakdown. This is because, during the pump operation for transferring the liquid, the vibration plate 106 bends and the movement is transmitted to the seal portion sandwiched between the inner plate 104 and the lid 109. It is considered that the gap has made it easy to leak.

Accordingly, an object of the present invention is to provide a piezoelectric pump in which liquid leakage from a pump chamber is prevented.

[0007]

According to the present invention, there is provided a piezoelectric pump comprising:
A pump chamber having a vibration surface vibrated by a piezoelectric vibrator, a check valve is provided on each of a primary flow path side and a secondary flow path side, and a liquid is conveyed by a pump operation due to vibration of the vibration surface. Inside, an inner plate having the check valve and a cartridge to which the piezoelectric vibrator is adhered are incorporated in a stack, and a space between the inner plate and the cartridge is used as the pump chamber, The cartridge is characterized by comprising a vibrating portion on the bottom surface to which the piezoelectric vibrator is adhered, and a thick-walled cylindrical guide portion pressed against the inner plate side at a peripheral portion thereof.

Therefore, in the piezoelectric pump of the present invention, when the piezoelectric vibrator expands and contracts in the radial direction and generates bending vibration, the vibrating portion of the cartridge also generates bending vibration.
The volume of the pump chamber expands and contracts, and the suction and discharge of the liquid are repeated. At that time, the cartridge is positioned around the vibrating portion that vibrates by the guide portion having high rigidity, so that the sealing portion around the pump chamber has good stability and liquid leakage from the pump chamber can be prevented. became.

Further, the piezoelectric pump of the present invention is characterized in that the pump chamber communicates with the primary flow path side and the secondary flow path side, and a valve hole which is opened and closed by the check valve is a long hole.
Therefore, according to the piezoelectric pump of the present invention, the passage cross-sectional area can be increased as compared with the conventional one in which a plurality of valve holes having a circular cross section are provided, the pressure loss of the liquid is suppressed, and the liquid is efficiently transported. Is now available.

Further, in the piezoelectric pump according to the present invention, the inner plate is pressed against the cartridge, and an annular groove for inserting a sealing O-ring is formed in a peripheral portion surrounding the pump chamber. A discharge groove connected to the valve hole of the check valve on the secondary flow path side is formed. Therefore, according to the present invention, if the piezoelectric pump is arranged so that the discharge groove is straight up and down at the center, the air in the pump chamber rises into the annular groove and rises through the discharge groove according to the pump operation. It is gradually pushed out from. Therefore, the air in the pump chamber can be discharged by its own pump operation, and the deterioration of the pump characteristics due to the air can be avoided.

Further, in the piezoelectric pump of the present invention, the primary flow path and the secondary flow path are made common, and two pump chambers formed in a space between the inner plate and the cartridge are provided in one pump main body. It is characterized by having. Therefore,
ADVANTAGE OF THE INVENTION According to the piezoelectric pump of this invention, the liquid of a suitable flow can be conveyed by controlling single or double, or the vibration frequency of a piezoelectric vibrator suitably according to the viscosity of the liquid to convey. In addition, the piezoelectric pump itself can be made compact while being a double pump.

[0012]

Next, an embodiment of a piezoelectric pump according to the present invention will be described with reference to the drawings. FIG.
FIG. 2 is a sectional view showing such a piezoelectric pump of the present embodiment, and FIG. 2 is an exploded perspective view in which one of the same piezoelectric pump is disassembled. The piezoelectric pump 1 of the present embodiment is of a double pump type in which two pumps are integrally provided between input / output ports.

The pump body 2 is formed with circular concave pump assembly portions 5 and 6 on both sides of the flow path.
A primary side flow path 7 communicating with the pump assembly parts 5, 6 and a secondary side flow path 8 communicating with the output port 4 from the pump assembly parts 5, 6 are formed. The pumps having the same configuration are provided in both of the pump assembly sections 5 and 6. Therefore, regarding the configuration of the pump, the same numbers will be assigned to both members, and only one side will be described.

The pump assembly 5 is loaded with an inner plate 13 having check valves 11 and 12 and a cartridge 15 to which a piezoelectric vibrator 14 is adhered, and a cover screwed to the pump body 2. It is closed by 16. The inner plate 13 is a disk slightly smaller than the diameter of the pump assembly section 5 so that the check valves 11 and 12 are appropriately arranged at the opening portions of the primary flow path 7 and the secondary flow path 8. The pump assembly 5 is fitted into the projection and positioned.

On the other hand, the cartridge 15 includes the piezoelectric vibrator 1
4 is a so-called container-shaped structure including a vibrating portion 15B on the bottom surface to which the adhesive member 4 is adhered and a thick cylindrical guide portion 15A standing upright on the peripheral portion thereof. The inner plate 13 is mounted in such a manner that the inner plate 13 is pressed tightly against the pump body 2 at the guide portion 15A. Inner plate 13
An annular groove 31 is formed on the surface of the guide portion 15A against which the guide portion 15A is pressed, and an O-ring 17 for sealing is mounted. The pump chamber 18 is formed with a small gap formed by being shallowly recessed on the inside surrounded by the annular groove 31 and closed by the vibrating portion 15B of the cartridge 15.

FIG. 3 is a plan view showing the pump chamber 18 side of the inner plate 13. The check valve 11 for the input side is provided symmetrically with respect to the center point of the inner plate 13.
And a check valve 12 for the output side. Piezoelectric pump 1
Check valves 11 and 12 are umbrella valves. Positioning holes 32 and 33 for inserting and fixing a handle portion are provided at symmetrically provided mounting points, and valves which become liquid passages are provided. Holes 34 and 35 are formed. In particular, in this embodiment, the shape of the valve holes 34 and 35 is made into a curved long hole so that the flow path cross-sectional area becomes large. Further, a recess 36 in which the output valve 12 is mounted and the annular groove 31 are connected to the inner plate 13 by a discharge groove 37.

The cartridge 15 is formed thin so that the vibrating portion 15B to which the piezoelectric vibrator 14 is bonded does not affect the pump operation. As described above, in the piezoelectric pump 1, the vibrating portion 15 </ b> B forms one surface of the pump chamber 18, and the surface performs amplitude operation by the piezoelectric vibrator 14 to perform the pumping operation. Is reduced, and the carrying capacity is reduced. For this reason, the vibrating portion 15B is formed with a thickness enough to exhibit the required transfer capability.

The piezoelectric vibrator 14 bonded to the vibrating part 15B
Is a bimorph type in which two piezoelectric bodies are bonded, a membrane electrode is adhered, and a lead wire 21 connected to the membrane electrode extends out of the pump body. And
The piezoelectric vibrator 14 is bonded to a thin portion formed in the vibrating portion 15B by an elastic adhesive. In the present embodiment, the bimorph type piezoelectric vibrator 14 in which the piezoelectric bodies are laminated as described above is used.
In addition, a single-layer unimorph type may be used. Therefore,
In the piezoelectric pump 1, the inner plate 13 and the cartridge 15 configured as described above are sequentially fitted into the pump assembly unit 5, and they are pressed down by the cover 16 screwed to the pump body 2 so that there is no play as shown in FIG. It has become one.

Subsequently, in the piezoelectric pump 1 configured as described above, the liquid is conveyed by the following operation. In the piezoelectric pump 1, when a voltage is applied to the piezoelectric vibrator 14, the piezoelectric vibrator 14 expands and contracts in the radial direction and generates bending vibration. Therefore, the vibration part 15B of the cartridge 15 bends and vibrates in the same manner as the piezoelectric vibrator 14 to which the adhesive is bonded, and the volume of the pump chamber 18 expands / contracts, so that the chamber becomes a negative pressure or is pressurized. A pump operation that repeats suction and discharge is performed. Specifically, first, when the vibrating portion 15B of the cartridge 15 bends in the direction in which the volume of the pump chamber 18 is expanded according to the piezoelectric vibrator 14, the liquid is sucked and flows into the pump chamber 18 which has become a negative pressure. At this time, the liquid on the secondary side does not flow into the pump chamber 18 because the valve hole 34 is closed by the check valve 12.

Then, the pump chamber 18 is sucked by the liquid.
Is filled, a reverse voltage is applied to the piezoelectric vibrator 14, and if the vibrating part 15B flexes in a direction to reduce the volume of the pump chamber 18, the filled liquid is pressurized and pushed out. The pressurized liquid does not flow back to the primary side by the check valve 11, but is discharged from the check valve 12 side to the secondary side. Therefore, in the piezoelectric pump 1, by controlling the switching of the voltage applied to the piezoelectric vibrator 14, the vibration part 15B of the cartridge 25 constituting the pump chamber 18 is vibrated, and the liquid sucked from the primary side is continuously discharged. The liquid to be discharged to the next side is conveyed.

Therefore, according to the piezoelectric element pump 1 of the present embodiment, the use of the cartridge 15 can prevent the leakage of the liquid entering the pump chamber 18,
Problems such as corrosion and dielectric breakdown of the piezoelectric vibrator 14 have been eliminated. This is because the guide portion 15A having high rigidity is provided in the seal portion.
Is pressed and sealed, even if the vibrating portion 15B is subjected to bending vibration by the piezoelectric vibrator 14, the movement is not transmitted to the sealing portion, and the movement between the inner plate 13 including the O-ring 17 and the cartridge 15 is prevented. This is because the adhesion has improved. In the present embodiment, the O-ring 17 is fitted in the annular groove 31 formed in the inner plate 3 for the purpose of air bleeding described later.
You may make it seal with the pump main body 2.

If the piezoelectric vibrator 14 adhered to the bottom surface of the cartridge 15 is covered with an elastic adhesive, depending on the type of liquid to be conveyed, even if the liquid leaks, it is necessary to take measures for explosion-proof measures. Can be. Further, the piezoelectric element pump 1 has the valve holes 34 and 35 which flow into and out of the pump chamber 18 and have long holes, so that the piezoelectric element pump 1 has a plurality of valve holes having a circular cross section. As a result, the passage cross-sectional area can be increased, the pressure loss of the liquid can be suppressed, and the liquid can be transported efficiently. Further, the inner plate 13 is attached to the pump assembly parts 5 and 6.
And the cartridge 15 are fitted and pressed by the cover 16, so that maintenance can be easily performed simply by removing the cover 16.

Incidentally, the conventional piezoelectric pump has a problem in that when pumping a liquid, pump characteristics are not stabilized due to air accumulated in the pump chamber 18. This is because the air is a compressive fluid, and is compressed by the pressing force when the liquid is discharged, so that the volume decreases, and the liquid is not efficiently pushed out by the pump operation of the diaphragm 15B. Therefore, in the present embodiment, air is evacuated so that such air can be removed and the pump characteristics can be kept stable.

In the present embodiment, in order to perform such air bleeding, the output port 4 is turned upward, and the piezoelectric pump 1 is arranged vertically and used. That is, as shown in FIG. 3, the inner plate 13 is disposed such that the discharge groove 37 is vertically straight at the center position. It should be noted that even when the piezoelectric pump 1 is placed horizontally as shown in FIG. 2, a design change for achieving the effect is possible, and there is no particular way to achieve other effects in the present invention. is not a problem. In the piezoelectric pump 1, the pump chamber 1
The liquid sucked by the liquid 8 and discharged therefrom is sucked from the lower valve hole 34 shown in FIG. 3 and discharged from the upper valve hole 35. May be left without being ejected.

On the other hand, in the present embodiment, the air in the pump chamber 18 rises as it is, or enters the annular groove 13A by the pressurization in the pump chamber 18 and rises as shown by a broken line, and The air collected in 18 collects in the upper part of the annular groove 13A. And
When the pump operation is repeated, the pressurized liquid is also pushed outward and enters the annular groove 13A.
The air is gradually pushed up from below in the annular groove 13A. The air that has no place to go to is discharged only along the discharge groove 37 connected to the valve hole 35 as the liquid is discharged by the pump operation because the outlet is only at the discharge groove 37 portion. The Rukoto.

Therefore, in the piezoelectric pump 1, the pump chamber 18
The inside air can be discharged by its own pump operation, so that the pump characteristics can be prevented from deteriorating due to the air, and the liquid can be transported efficiently.

Next, in the piezoelectric pump 1 according to the present embodiment, the liquid transfer as described above is performed simultaneously by two pumps.
That is, the liquid that has flowed in from the input port 3 is sucked by being divided into two pump chambers 18, 18 from one primary channel 7, and one secondary channel 8 from each pump chamber 18, 18 again.
And are merged. The piezoelectric pump 1 has a double pump structure, and both piezoelectric vibrators 14, 1
By controlling the number 4, the liquid having a flow rate almost twice that of the case where one of the piezoelectric vibrators 14 is driven can be conveyed.

By the way, even when the piezoelectric pumps having the same performance are controlled in the same manner, the transport flow rate may decrease depending on the transported liquid. This is because as the liquid becomes higher in viscosity, the power of the piezoelectric vibrator 14 that pushes out the liquid becomes insufficient or the pressure loss increases. However, the piezoelectric pump 1 of the present embodiment has a double pump structure, so that the piezoelectric vibrator 1 driven according to the difference in liquid viscosity is used.
It is possible to switch the control of 4, 14 to obtain the required flow rate.

If the liquid has low viscosity, it is used as a single pump for controlling only one of the piezoelectric vibrators 14. If the viscosity increases and the transport amount decreases, both piezoelectric vibrators 14, 14 are used. This is because a proper amount of liquid can be efficiently transported by using the double pump to be driven. Therefore, according to the piezoelectric pump 1,
By appropriately controlling the vibration frequency of the single or double or piezoelectric vibrators 14 according to the viscosity of the liquid to be conveyed, it is possible to convey the liquid at an appropriate flow rate.
Moreover, the piezoelectric pump 1 itself could be made compact while being a double pump.

The embodiment of the piezoelectric pump according to the present invention has been described above. However, the present invention is not limited to this, and various changes can be made without departing from the gist of the present invention. For example, in the above embodiment, two pumps are provided in order to obtain the effect of the double pump, but only one pump may be used.

[0031]

According to the present invention, the pump chamber is provided by providing a vibrating portion on the bottom surface to which the piezoelectric vibrator is adhered and a thick cylindrical guide portion for pressing against the inner plate side at the peripheral portion thereof. It has become possible to provide a piezoelectric pump that prevents liquid leakage from the pump.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a piezoelectric pump according to the present invention.

FIG. 2 is an exploded perspective view showing one embodiment of the piezoelectric pump according to the present invention.

FIG. 3 is a plan view showing an inner plate.

FIG. 4 is a sectional view showing a conventional piezoelectric pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric pump 2 Pump main body 5, 6 Pump assembly part 11, 12 Check valve 13 Inner plate 14 Piezoelectric vibrator 15 Cartridge 15A Vibration part 15B Guide part 18 Pump room

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H071 AA01 BB01 BB13 CC11 CC28 CC33 CC41 DD04 DD14 DD60 3H075 AA01 AA17 BB04 BB14 BB16 BB20 CC16 CC25 CC34 DA09 DB02 3H077 AA01 CC02 CC09 CC17 DD06 EE02 FF26 FF12 FF

Claims (4)

[Claims] 1. A pump chamber having a vibration surface vibrated by a piezoelectric vibrator is provided with a check valve on each of a primary flow path side and a secondary flow path side, and a liquid is conveyed by a pump operation by vibration of the vibration surface. Further, an inner plate provided with the check valve and a cartridge to which the piezoelectric vibrator is adhered are superposed and incorporated in a pump body, and a space between the inner plate and the cartridge is used as the pump chamber. In the pump, the cartridge may include a vibrating portion on a bottom surface to which the piezoelectric vibrator is adhered, and a thick cylindrical guide portion pressed against a peripheral portion of the cartridge toward the inner plate. pump. 2. The piezoelectric pump according to claim 1, wherein the pump chamber communicates with a primary channel and a secondary channel.
The valve pump which is opened and closed by the check valve is a long hole. 3. The piezoelectric pump according to claim 1, wherein the inner plate is pressed against the cartridge, and an annular groove for inserting an O-ring for sealing is formed in a peripheral portion surrounding the pump chamber. And a discharge groove formed from the annular groove to a valve hole of the check valve on the secondary flow path side. 4. The piezoelectric pump according to claim 1, wherein the primary flow path and the secondary flow path are shared, and the piezoelectric pump is formed in a space between the inner plate and the cartridge. A piezoelectric pump, wherein one pump chamber is provided in one pump body.