JP2001020866A - Piezo pump - Google Patents

Abstract

(57) [Problem] To provide a piezoelectric pump which does not require a complicated control circuit. SOLUTION: A first pump chamber 2 provided in a case 1 is connected to a second pump chamber 3 via a first fluid moving path 5;
Inflow path 4 for moving fluid into first pump chamber 2
And an outflow passage 6 for moving fluid from the second pump chamber 3.
And diaphragms 9, 10 provided in the first and second pump chambers 2, 3.
First and second piezoelectric vibrators 7 and 8 having piezoelectric elements 11 and 12 attached thereto, and lead terminals 13a, 13b, 14a and 14b connected to the first and second piezoelectric vibrators 7 and 8, respectively. The outer peripheral portions of the first and second piezoelectric vibrators 7 and 8 are fixed to the first and second pump chambers 2 and 3 inner wall surfaces.
Thus, the opening of the inflow path 4 on the first pump chamber 2 side was covered, and the second piezoelectric vibrator 8 covered the opening of the first fluid transfer path 5 on the second pump chamber 3 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric pump that requires strict control of a flow rate such as a medical instrument.

[0002]

2. Description of the Related Art As shown in FIG. 17, a conventional pump has first and second piezoelectric vibrators 103 and 104 in which a piezoelectric element is attached to a vibration plate inside a case 102 having an inflow path 100 and an outflow path 101. The first and second piezoelectric vibrators 103 and 104 are provided with a case 102, respectively.
And the inner wall surface of the inner wall and the projection 105 provided at the center of the inner wall, and seals the inflow channel 100 and the outflow channel 101.

[0003] First and second piezoelectric vibrators 103, 10
4 are lead terminals 106a, 106b, 107a, 107
b is connected to one end and the other end is connected to the case 10.
2 and connected to a drive power source 108 having a control circuit.

In this pump, a fluid is moved by applying a voltage from a driving power supply 108 to vibrate the first and second piezoelectric vibrators 103 and 104 to open and close the inflow path 100 and the outflow path 101 alternately. Things.

[0005]

According to this configuration, the first
As shown in FIG. 18, the first piezoelectric vibrator 103 and the second piezoelectric vibrator
It is necessary to apply a voltage for shifting the waveform of No. 4. There is a problem that a complicated control circuit is required to control the voltage having the shifted waveform.

Accordingly, an object of the present invention is to provide a piezoelectric pump that does not require a complicated control circuit.

[0007]

In order to achieve this object, a piezoelectric pump according to the present invention comprises a case, a first pump chamber provided in the case, and a first pump chamber and a first fluid moving path. A second pump chamber connected to the first pump chamber via the second pump chamber, an inflow passage for moving the fluid from outside the case to the inside of the first pump chamber, and a flow path for moving the fluid from the second pump chamber to the outside of the case. Outgoing passages and first and second piezoelectric elements attached to diaphragms provided in the first and second pump chambers.
A piezoelectric vibrator, and a lead terminal having one end connected to the first and second piezoelectric vibrators and the other end drawn out of the case, and an outer peripheral portion of the first and second piezoelectric vibrators, The first piezoelectric vibrator fixes the first pump chamber side opening of the inflow path with the first piezoelectric vibrator, and the second piezoelectric vibrator fixes the first fluid moving path of the first fluid moving path. 2 Covers the pump chamber side opening,
The above object can be achieved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a case, a first pump chamber provided in the case,
A second pump chamber connected to the first pump chamber via a first fluid movement path, an inflow path for moving fluid from outside the case to the inside of the first pump chamber, and the second pump chamber. Outflow passages for fluid to move from the case to the outside of the case; first and second piezoelectric vibrators each having a piezoelectric element attached to a vibration plate provided in the first and second pump chambers; A lead terminal having one end connected to the second piezoelectric vibrator and the other end drawn out of the case; and an outer peripheral portion of the first and second piezoelectric vibrators being connected to the first and second piezoelectric vibrators.
The first piezoelectric vibrator fixes the opening of the inflow path on the first pump chamber side with the second piezoelectric vibrator.
This is a piezoelectric pump in which a piezoelectric vibrator covers the opening of the first fluid movement path on the second pump chamber side, and can be driven without using a complicated control circuit.

According to a second aspect of the present invention, in the first and second piezoelectric vibrators, the vibrating plates are installed on the inflow path and the second fluid moving path side, and the polarities of the piezoelectric elements on the vibrating plate side are different from each other. Item 1. The piezoelectric pump according to item 1, wherein the first and second
Since the diaphragm applied to the diaphragm in contact with the fluid can be reduced to zero while driving the diaphragm of the pump chamber in the opposite phase,
It can prevent short-circuit and leakage due to fluid.

According to a third aspect of the present invention, an elastic body is provided between the inflow path and the first piezoelectric vibrator and between the second piezoelectric vibrator and the fluid moving path in contact with the second piezoelectric vibrator. The piezoelectric pump according to claim 1, wherein the flow rate can be increased by facilitating the displacement of the piezoelectric vibrator in the fluid pumping direction after the diaphragm seals the inflow path and the fluid moving path.

According to a fourth aspect of the present invention, the outer peripheral surface of the elastic body, the inner wall surface of the first pump chamber side opening of the inflow passage, and the inner wall surface of the second pump chamber side opening of the fluid moving passage are tapered in the same direction. The piezoelectric pump according to claim 3, wherein the elastic body has a larger taper angle than each of the inner wall surfaces, and can improve sealing when the inflow path and the fluid movement path are closed, Loss due to backflow can be prevented.

According to a fifth aspect of the present invention, there is provided the piezoelectric pump according to any one of the first to fourth aspects, wherein the first and second pump chambers have curved corners. The occurrence of turbulence in the fluid can be suppressed, and an increase in the flow resistance of the fluid can be prevented.

According to a sixth aspect of the present invention, the voltage applied to the first and second piezoelectric vibrators has a shift of 1/4 cycle or less (excluding the same cycle). The piezoelectric pump according to any one of the above, wherein a flow loss due to a backflow is suppressed, and the flow rate can be increased.

According to a seventh aspect of the present invention, a third pump chamber is provided between the first fluid movement path and the second pump chamber.
A third piezoelectric vibrator having an outer peripheral portion fixed to the wall surface of the third pump chamber is provided in the third pump chamber, one end of a lead terminal is connected to the third piezoelectric vibrator, and the other end is drawn out of the case. The piezoelectric pump according to any one of claims 1 to 5, wherein the third pump chamber and the second pump chamber are connected by a second fluid passage, and the pump chamber is increased. , The flow rate can be increased.

According to an eighth aspect of the present invention, the polarity of the piezoelectric element of the third piezoelectric vibrator on the diaphragm side is the same as the polarity of the piezoelectric element of the first piezoelectric vibrator on the diaphragm side. Since this is a piezoelectric pump, the third piezoelectric vibrator can be driven in the same phase as the first piezoelectric vibrator and in the opposite phase to the second piezoelectric vibrator, and the potential applied to the diaphragm in contact with the fluid can be made zero. Short circuit and leakage due to fluid can be prevented.

According to a ninth aspect of the present invention, the voltages applied to the first and second piezoelectric vibrators are in phase, and the voltage applied to the third piezoelectric vibrator is applied to the first and second piezoelectric vibrators. The piezoelectric pump according to claim 7, wherein the applied voltage has a shift of 1/4 cycle or less (excluding the same cycle) with respect to the applied voltage, wherein the flow rate loss due to the backflow is suppressed and the flow rate is increased. it can.

According to a tenth aspect of the present invention, there is provided the piezoelectric pump according to any one of the first to eighth aspects, wherein a gas is present in at least the first and second pump chambers when the pump is driven. Yes, the gas expands and contracts due to pressure fluctuations in the pump chamber, and maintains the pressure between the pump chambers, and the opening and closing of the inflow path and the fluid transfer path due to dimensional variations of the components when manufacturing the piezoelectric pump. Variations in flow rate due to timing deviation can be suppressed.

According to an eleventh aspect of the present invention, in the piezoelectric pump according to any one of the first to tenth aspects, the connection between the lead terminal and each of the piezoelectric vibrators is performed using a conductive adhesive. In addition, since the connection is made by an elastic body, it is possible to suppress the vibration of the piezoelectric vibrator from being hindered.

According to a twelfth aspect of the present invention, there is provided the piezoelectric pump according to any one of the first to eleventh aspects, wherein a marking is provided on at least one of the inflow path side and the outflow path side of the case. Errors can be prevented.

According to a thirteenth aspect of the present invention, there is provided the piezoelectric pump according to any one of the first to twelfth aspects, wherein the diaphragm is formed using metal. It suppresses abrasion due to contact with steel and has excellent long-term reliability.

According to a fourteenth aspect of the present invention, there is provided the piezoelectric pump according to any one of the first to thirteenth aspects, wherein a sectional shape of each pump chamber parallel to each piezoelectric vibrator is circular. It suppresses the generation of a flow and prevents an increase in the flow resistance of the fluid.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a piezoelectric pump according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view of the same.

In the figure, reference numeral 1 denotes a case. First and second pump chambers 2 and 3 are provided inside the case 1. The first pump chamber 2 includes a first piezoelectric vibrator 7 in which a piezoelectric element is attached to a vibration plate 9. Similarly, in the second pump chamber 3, a second piezoelectric element is attached to the vibration plate 10.
A piezoelectric vibrator 8 is provided.

The first and second piezoelectric vibrators 7 and 8 are
Piezoelectric elements 11 and 12 having electrodes on both surfaces are provided with lead terminals 13a, 13b, 14a and 14b for electrically connecting one ends of the piezoelectric elements 11 and 12 and the vibrating plates 9 and 10, respectively. The power supply 15 is electrically connected to the middle point between the lead terminals 13a and 13b and the middle point between the lead terminals 14a and 14b.

Also, the first pump chamber 2
The inflow passage 4 for moving fluid to the first pump chamber 2 and the second
The pump chamber 3 connects the first fluid movement path 5 and the outflow path 6 through which the fluid is moved from the second pump chamber 3 to the outside of the case 1.

The first pump chamber 2 configured as described above has a substantially circular shape when viewed from the upper surface, and has lead terminals 13a and 13b on the upper surface side of the case 1. The first piezoelectric vibrator 7 is also substantially circular when viewed from above, and has a state in which the entire outer peripheral portion of the diaphragm 9 is supported by the inner wall surface in the thickness direction of the first pump chamber 2. 4 is closed. The first piezoelectric vibrator 7 other than the outer peripheral portion of the vibrating plate 9 and the portion blocking the inflow path 4 is in a non-contact state with the inner wall surface of the first pump chamber 2. Further, the lead terminals 13a, 13b, the diaphragm 9 of the first piezoelectric vibrator 7, and the electrodes of the piezoelectric element 11 are electrically connected and fixed with a conductive adhesive.

The second pump chamber 3 has almost the same configuration as the first pump chamber 2, and only different portions will be described. In the first pump chamber 2, the inflow path 4 is closed by the diaphragm 9, but in the second pump chamber 3, the first fluid transfer path 5 is closed by the diaphragm 10. Lead terminals 13a and 14
a, 13b and 14b are electrically connected outside the case 1 and then to the power supply 15 and the ground.

The first and second piezoelectric vibrators 7 and 8 have vibration plates 9 and 10 installed on the inflow path 4 and the first fluid movement path 5 side, and have the piezoelectric elements 11 and 12 on the vibration plate 9 and 10 side. Have opposite polarities. This is to drive the first and second piezoelectric vibrators 7 and 8 in opposite phases while setting the potential applied to the vibrating plates 9 and 10 in contact with the fluid to 0, thereby preventing short-circuit and leakage due to the fluid.

FIG. 3 shows the operation of the piezoelectric pump.
This will be described with reference to FIG. In FIGS. 3A and 3B, arrows indicate the direction in which the fluid flows.

First, when a voltage is applied by the power supply 15, FIG.
3A and 3B are alternately repeated.

That is, in FIG. 3A, the first piezoelectric vibrator 7 bends above the case 1 and, conversely, the second piezoelectric vibrator 8 bends below the case 1. At this time, a gap is generated between the diaphragm 9 and the inflow path 4, and the fluid flows into the first pump chamber 2. Further, in the second pump chamber 3, the diaphragm 10 keeps closing the first fluid moving path 5, and the fluid in the second pump chamber 3 is pushed out of the case 1 from the outflow path 6 by flexing below the case 1. Will be.

In FIG. 3B, when the first piezoelectric vibrator 7 bends below the case 1 and the second piezoelectric vibrator 8 bends above the case 8, the diaphragm 9 in the first pump chamber 2 is bent.
While the inflow channel 4 is closed, the first
The fluid is pushed out to the second pump chamber 3 through the fluid moving path 5. In the second pump chamber 3, a gap is formed between the diaphragm 10 and the first fluid moving path 5, so that the fluid pushed out in the first pump chamber 2 moves to the second pump chamber 3. By alternately repeating the operations shown in FIGS. 3A and 3B, the fluid moves smoothly.

(Second Embodiment) FIG. 4 is a sectional view of a piezoelectric pump according to a second embodiment. Here, the same components as those of FIG. 4 in the present embodiment and FIGS. 1 to 3 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The difference from the first embodiment is that the piezoelectric element 1
1 and 12 are formed on one diaphragm 20.
With this configuration, the number of lead terminals 21 connected to the first and second piezoelectric vibrators 7 and 8 can be reduced, and
The connection between the lead terminal 21 and the diaphragm 20 can be easily performed. Also, the manufacturing process is easier than that of the piezoelectric pump of the first embodiment.

Third Embodiment FIGS. 5 and 6 are sectional views of a piezoelectric pump according to a third embodiment. Here, the same components as those in FIGS. 1 to 3 of the present embodiment and the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the inflow path 4 and the first
An elastic body 30 is provided between the piezoelectric vibrators 7 and between the first fluid moving path 5 and the second piezoelectric vibrator 8. This elastic body 30 is shown in FIG.
May be provided on the diaphragms 9 and 10 side, or may be provided on the inflow path 4 and the first fluid moving path 5 side as shown in FIG.

After the vibrating plates 9 and 10 seal the inflow path 4 and the first fluid moving path 5 by providing the elastic body 30, the first and second piezoelectric vibrators 7 and
By making it easier to displace 8, the flow rate can be increased.

(Fourth Embodiment) FIGS. 7 and 8 are sectional views of a piezoelectric pump according to a fourth embodiment. Here, the same components as those in FIGS. 1 to 3 of the present embodiment and the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 7, the elastic members 30 are provided on the diaphragms 9 and 10, and the portions of the elastic members 30, the inflow passage 4 and the inner wall surface of the first fluid moving passage 5 which contact the elastic member 30 are tapered in the same direction. It is formed in a shape. The elastic body 30 has a taper angle of the inflow path 4 and the first fluid movement path 5.
Larger than.

In FIG. 8, an elastic body 30 is provided on the inflow path 4 and the first fluid moving path 5 side,
10 is provided with a tapered projection 31. At this time, the taper angle of the projection 31 is larger than the taper angle of the elastic body 30.

With such a structure, the sealing state of the inflow path 4 and the first fluid moving path 5 by the vibration plates 9 and 10 is further improved, and the backflow of the fluid can be further reduced.

(Fifth Embodiment) FIG. 9 is a sectional view of a piezoelectric pump according to a fifth embodiment, and FIGS.
5 is a waveform diagram of a voltage applied to the piezoelectric pump shown in FIG. Here, the same components as those in FIGS. 1 to 3 of the present embodiment and the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, the voltage applied to the first and second piezoelectric vibrators 7 and 8 by the drive power supply 40 is 1 /
It is shifted within a range of four cycles or less. This is the same whether the applied voltage is a sine wave as shown in FIG. 10 or a rectangular wave as shown in FIG.

As described above, the first and second piezoelectric vibrators 7, 8
By shifting the cycle (T) of the voltage to be applied to the fluid in a range of 1/4 cycle or less, it is possible to optimize the timing of the opening and closing of the inflow passage 4 and the first fluid moving passage 5 and the timing of the fluid pumping operation. Can be increased to increase the flow rate.

The amount by which the cycle of the applied voltage is shifted (Δ
t) is determined in consideration of the frequency characteristics of the entire piezoelectric pump including the fluid, as well as the first and second piezoelectric vibrators 7 and 8.

(Sixth Embodiment) FIG. 12 is a sectional view of a piezoelectric pump according to a sixth embodiment. Here, the same components as those in FIGS. 1 to 3 of the present embodiment and the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, a third pump chamber 50 is provided in addition to the first and second pump chambers 2 and 3, so that the first
It is connected to the pump chamber 2 via the first fluid moving path 5 and connected to the second pump chamber 3 via the second fluid moving path 51.

The third pump chamber 50 is provided with a vibration plate 52 and a third piezoelectric vibrator 54 composed of a piezoelectric element 53, similarly to the first and second pump chambers 2 and 3. Also lead terminals 5
One end of each of 5a and 55b is electrically connected to the vibration plate 52 and the piezoelectric element 53, and the other end is drawn out of the case 1 and connected to the power supply 15 and the ground.

The polarity of the piezoelectric element 53 on the diaphragm 52 side is the same as that of the piezoelectric element 11 and opposite to that of the piezoelectric element 12. This is because the third piezoelectric vibrator 54 is driven in the same phase as the first piezoelectric vibrator 7 and in the opposite phase to the second piezoelectric vibrator 8, and the potential applied to the vibrating plates 9, 10 and 52 in contact with the fluid is set to 0. In order to prevent short-circuit and leakage due to fluid.

FIG. 13 shows the operation of the piezoelectric pump.
This will be described with reference to FIG. In the figure, the direction of movement of the fluid is indicated by arrows.

When a voltage is applied to the piezoelectric pump by the power supply 15, the operations shown in FIGS. 13A and 13B are alternately repeated.

That is, in FIG. 13A, the first
The piezoelectric vibrator 7 bends upward, and the second and third piezoelectric vibrators 8 and 54 bend downward. Therefore, the inflow path 4 and the diaphragm 9
A space is created between the first and second pump chambers, and the fluid flows from the first pump chamber 2 to the third pump chamber 50. At this time, the second pump chamber 3
Since the fluid passage 51 is sealed with the diaphragm 10,
The pumping of the fluid from the pump chamber 50 to the second pump chamber 3 is not performed, but the case 1
Will be pumped out of the device.

On the other hand, as shown in FIG. 13B, when the first piezoelectric vibrator 7 bends downward and the second and third piezoelectric vibrators 8 and 54 bend upward, the first piezoelectric vibrator 7 flows into the first pump chamber 2. Since the passage 4 is sealed by the vibration plate 9, the fluid is not pumped from the inflow passage 4 to the first pump chamber 2, but the fluid is pumped from the first pump chamber 2 to the third pump chamber 50. You.

In the second pump chamber 3, a space is formed between the second fluid moving path 51 and the diaphragm 10, so that fluid is pumped from the third pump chamber 50 to the second pump chamber 3 and the second pump chamber 3 Fluid is pumped from the pump chamber 3 to the outside of the case 1 via the outflow passage 6.

By performing the operations shown in FIGS. 13A and 13B alternately and repeatedly, the fluid moves smoothly via the piezoelectric pump.

(Embodiment 7) FIG. 14 shows Embodiment 7 of the present invention.
It is sectional drawing of the piezoelectric pump in FIG. Here, the same components as those in FIGS. 1 to 3 of the present embodiment and the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, as in the second embodiment, the piezoelectric elements 11 and 12 are formed on one vibration plate 20. With this configuration, the number of lead terminals 21 connected to the first and second piezoelectric vibrators 7 and 8 can be reduced, and the connection between the lead terminals 21 and the diaphragm 20 can be easily performed.

(Eighth Embodiment) FIG. 15 shows the eighth embodiment.
It is sectional drawing of the piezoelectric pump in FIG. Here, the same components as those in FIGS. 1 to 3 of the present embodiment and the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, the voltages applied to the first and second piezoelectric vibrators 7 and 8 by the driving power supply 40 are in phase, and the voltages applied to the third piezoelectric vibrator 54 are changed to the first and second piezoelectric vibrators 54. The voltage applied to the piezoelectric vibrators 7 and 8 is shifted in a range of 1/4 cycle or less (excluding the same cycle). As a result, the flow rate loss due to the backflow can be suppressed, and the flow rate can be increased.

This is the same regardless of whether the applied voltage is a sine wave as shown in FIG. 10 or a rectangular wave as shown in FIG.

As described above, the first and second piezoelectric vibrators 7 and 8
The period (T) of the voltage applied to the third piezoelectric vibrator 54 and the period (T) of the voltage applied to the third piezoelectric vibrator 54 are shifted in a range of 以下 cycle or less, so that the inflow path 4 and the second fluid moving path 51 are opened and closed. And the timing of the fluid pumping operation can be optimized, the backflow can be reduced and the flow rate can be increased.

The amount by which the cycle of the applied voltage is shifted (Δ
t) is determined in consideration of the frequency characteristics of the entire piezoelectric pump including the fluid, as well as the first to third piezoelectric vibrators 7, 8, and 54.

Embodiments 6 to 8 correspond to Embodiments 1 to 5
In comparison with the piezoelectric pump described above, the piezoelectric pump has a larger flow rate by one pump chamber.

In the sixth to eighth embodiments, similarly to the fourth embodiment, the space between the inflow passage 4 and the diaphragm 9 and the second
The same effect can be obtained by providing an elastic body between the fluid moving path 51 and the vibration plate 10.

Hereinafter, the point of the piezoelectric pump according to the embodiment of the present invention will be described.

(1) In each of the above embodiments, the case where an AC voltage is applied has been described. However, the piezoelectric pump operates even when a DC voltage is applied. However, in order to alternately bend the first to third piezoelectric vibrators 7, 8, and 54 up and down by applying a DC voltage, it is necessary to apply a potential to the vibration plates 9, 10, and 52. Also, when a potential is applied to the diaphragms 9, 10, 52, a short circuit or a short circuit occurs due to the fluid. Therefore, when a DC voltage is applied, the diaphragm 9,
It is necessary to insulate the contact surfaces of the fluids 10 and 52 with the fluid. Therefore, it is desirable to apply an AC voltage.

(2) As shown in FIG. 16, the electrical connection between the second piezoelectric vibrator 8 and the lead terminals 14a, 14b is made by using a conductive adhesive 60. With this configuration, the inhibition of the vibration of the second piezoelectric vibrator 8 can be suppressed, and the thickness of the joint can be reduced as compared with the case of the solder connection, that is, the thickness of the pump can be reduced. . Also, the conductive adhesive 60 is applied to the lead terminals 14a, 14b.
It is desirable to apply the coating so as to cover the joining-side end surface of the substrate to obtain a stronger joining.

This means that the first and third piezoelectric vibrators 7, 5
The same applies to No. 4.

(3) The piezoelectric pump is composed of piezoelectric elements 11, 12,
Since the frequency band 53 is used, it can be used in a wide frequency band. For example, if it is desired to make the generated sound difficult to hear, it is desirable to operate in a frequency range lower or higher than the audible range.

(4) The appearance of the piezoelectric pump is
And outflow path 6 are difficult to determine. Therefore, by marking at least one of the inflow path 4 and the outflow path 6 side of the case 1 to indicate the installation direction, it is possible to prevent the installation direction from being erroneous.

(5) By making the corners of the first to third pump chambers 2, 3, and 50 curved, the generation of turbulence at the corners is suppressed, and the flow resistance of the fluid is prevented from increasing. Can be.

(6) The diaphragms 9, 10, and 20 are made of metal to suppress wear due to contact with the inflow path 4 and the first or fluid moving paths 5, 51, and to provide excellent long-term reliability. It may be formed.

(7) In the first to third pump chambers 2, 3, and 50, gas is made to exist when the piezoelectric pump is driven, and the gas expands due to pressure fluctuations in the pump chambers 2, 3, and 50.
It contracts to maintain the pressure between the pump chambers 2, 3, and 50, and shifts in the opening and closing timing of the inflow passage 4 and the fluid transfer passages 5 and 51 due to dimensional variations of components when manufacturing the piezoelectric pump. The variation of the flow rate due to is suppressed.

(8) The diaphragms 9, 10, 20, 52 are larger than the inner peripheral shape of each pump chamber 2, 3, 50, and the piezoelectric elements 11, 12, 53 are smaller than the inner peripheral shape. Further, the shape of the piezoelectric elements 11, 12, 53 is desirably a disk shape in order to efficiently vibrate the first to third piezoelectric vibrators 7, 8, 54.

(9) The cross-sectional shape of the first to third pump chambers 2, 3, and 50 parallel to the first to third piezoelectric vibrators 7, 8, and 54 is circular, thereby reducing the flow resistance of the fluid. can do. This is because the presence of the corner generates turbulence and increases the flow resistance of the fluid.

(10) When no voltage is applied to the piezoelectric pump, the diaphragms 9, 10 and 20, the opening of the inflow passage 4 on the first pump chamber 2 side, and the second pump chamber of the first fluid transfer path 5 Even if there is a gap between the opening on the third side or the opening on the second pump chamber 3 side of the second fluid movement path 51, the operation is performed by applying a voltage.

However, in order to prevent the fluid from flowing backward when no voltage is applied, the diaphragms 9, 10, and 20 cover the openings as described in the above embodiments.

[0079]

According to the present invention, it is possible to provide a piezoelectric pump which does not require a complicated control circuit.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of the same.

FIG. 3 is a cross-sectional view for explaining the operation.

FIG. 4 is a sectional view of a piezoelectric pump according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a piezoelectric pump according to a third embodiment of the present invention.

FIG. 6 is a sectional view of the same.

FIG. 7 is a sectional view of a piezoelectric pump according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view of the same.

FIG. 9 is a sectional view of a piezoelectric pump according to a fifth embodiment of the present invention.

FIG. 10 is a waveform diagram of a voltage applied to the piezoelectric pump according to the fifth and eighth embodiments of the present invention.

FIG. 11 is a waveform diagram of a voltage applied to the piezoelectric pump according to the fifth and eighth embodiments of the present invention.

FIG. 12 is a sectional view of a piezoelectric pump according to a sixth embodiment of the present invention.

FIG. 13 is a sectional view for explaining the operation.

FIG. 14 is a sectional view of a piezoelectric pump according to a seventh embodiment of the present invention.

FIG. 15 is a sectional view of a piezoelectric pump according to an eighth embodiment of the present invention.

FIG. 16 is an enlarged sectional view of a main part of a piezoelectric pump according to an embodiment of the present invention.

FIG. 17 is a sectional view of a conventional piezoelectric pump.

18 is a waveform diagram of a voltage applied to the piezoelectric pump shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 1st pump chamber 3 2nd pump chamber 4 Inflow path 5 1st fluid movement path 6 Outflow path 7 1st piezoelectric vibrator 8 2nd piezoelectric vibrator 9 diaphragm 10 diaphragm 11 piezoelectric element 12 piezoelectric element 13a lead Terminal 13b Lead terminal 14a Lead terminal 14b Lead terminal 15 Power supply 20 Vibration plate 21 Lead terminal 30 Elastic body 31 Projection 40 Drive power supply 50 Third pump chamber 51 Second fluid movement path 52 Vibration plate 53 Piezoelectric element 54 Third piezoelectric vibrator 55a Lead terminal 55b Lead terminal 60 Conductive adhesive

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroyasu Ikeda 1006 Kadoma, Kazuma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. (reference) EE40 FF12 FF14 FF34 FF36

Claims (14)

[Claims] A first pump chamber provided in the case; a second pump chamber connected to the first pump chamber via a first fluid movement path; (1) an inflow passage for moving fluid into the pump chamber, an outflow passage for moving fluid from the second pump chamber to the outside of the case, and a diaphragm provided in the first and second pump chambers. A first and a second piezoelectric vibrator to which a piezoelectric element is attached, and a lead terminal having one end connected to the first and the second piezoelectric vibrator and the other end drawn out of the case; And fixing the outer peripheral portion of the second piezoelectric vibrator on the first and second pump chamber wall surfaces,
A piezoelectric pump in which a piezoelectric vibrator covers the first pump chamber side opening of the inflow path, and the second piezoelectric vibrator covers the second pump chamber side opening of the first fluid moving path. 2. The piezoelectric pump according to claim 1, wherein the first and second piezoelectric vibrators have the diaphragms installed on the inflow path and the second fluid movement path side, and the polarities of the piezoelectric elements on the diaphragm side are different from each other. . 3. The piezoelectric pump according to claim 1, wherein an elastic body is provided between the inflow path and the first piezoelectric vibrator and between the second piezoelectric vibrator and a fluid moving path in contact with the second piezoelectric vibrator. 4. The outer peripheral surface of the elastic body, the inner wall surface of the first pump chamber side opening of the inflow path, and the inner wall surface of the second pump chamber side opening of the fluid transfer path are tapered in the same direction, and the elastic body is more tapered. 4. The piezoelectric pump according to claim 3, which has a larger taper angle than each of said inner wall surfaces. 5. The piezoelectric pump according to claim 1, wherein corners of the first and second pump chambers are curved. 6. The piezoelectric device according to claim 1, wherein the voltage applied to the first and second piezoelectric vibrators has a shift of １ ／ cycle or less (excluding the same cycle). pump. 7. A third piezoelectric vibrator having a third pump chamber provided between the first fluid moving path and the second pump chamber, and an outer peripheral portion fixed to the wall surface of the third pump chamber in the third pump chamber. Wherein one end of a lead terminal is connected to the third piezoelectric vibrator and the other end is drawn out of the case, and the third pump chamber and the second pump chamber are connected by a second fluid moving path. The piezoelectric pump according to any one of claims 1 to 5. 8. The piezoelectric pump according to claim 7, wherein the polarity of the piezoelectric element of the third piezoelectric vibrator on the diaphragm side is the same as the polarity of the piezoelectric element of the first piezoelectric vibrator on the diaphragm side. 9. The voltage applied to the first and second piezoelectric vibrators is in phase, and the voltage applied to the third piezoelectric vibrator is one with respect to the voltage applied to the first and second piezoelectric vibrators. The piezoelectric pump according to claim 7, wherein the piezoelectric pump has a shift of ４ cycle or less (excluding the same cycle). 10. The piezoelectric pump according to claim 1, wherein gas is present in at least the first and second pump chambers when the pump is driven. 11. The connection between each piezoelectric vibrator and a lead terminal using a conductive adhesive.
0. The piezoelectric pump according to any one of 0. 12. The piezoelectric pump according to claim 1, wherein at least one of an inflow path side and an outflow path side of the case is marked. 13. The piezoelectric pump according to claim 1, wherein the diaphragm is formed using metal. 14. The piezoelectric pump according to claim 1, wherein a sectional shape of each pump chamber parallel to each piezoelectric vibrator is circular.