JP2001271756A - Piezoelectric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a piezoelectric pump for reducing manufacturing costs as well as facilitating assembly of a conventional piezoelectric pump. SOLUTION: In the piezoelectric pump for driving a diaphragm by enlarging displacement of a piezoelectric actuator with a lever, a center point of the diaphragm is positioned on either one side in the vicinity of a point where circular arc motion around the lever and a center axis of the diaphragm are brought into contact with each other, or a point which is brought into contact with the center axis of the diaphragm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a piezoelectric pump which has been made to facilitate assembly of a conventional piezoelectric pump and to reduce manufacturing costs.

[0002]

2. Description of the Related Art The structure of a conventional piezoelectric pump is shown in FIGS. 8, 9, 10, 11 and 12. FIG. 8 is a front view of a conventional piezoelectric pump, FIG. 9 is a longitudinal sectional view showing the internal structure of a conventional piezoelectric pump, FIG. 10 is a cross-sectional view showing the internal structure of a conventional piezoelectric pump, and FIG.
Is an enlarged longitudinal sectional view of a diaphragm portion attached to a conventional piezoelectric pump, and FIG. 12 is an enlarged longitudinal sectional view of a diaphragm attached to a conventional piezoelectric pump.

A conventional piezoelectric pump 31 includes a driving unit 31a and a pump unit 31b, as shown in FIGS. The driving unit 31a includes a diaphragm holder 45, a cover 48, a back plate 49, as shown in FIGS.
And an H-shaped hinge 52 in a casing composed of
Is fixed to one end and a piezoelectric actuator 54 to which a printed wiring board 55 is connected, a lever supporting leaf spring 53 is attached to one end, and a diaphragm joint 34 and a spring 47 are attached to the other end. An enlargement mechanism 31c, which is attached to the lever 43 to which the spring 33 is attached and the driving leaf spring 33 and includes a diaphragm fitting 32 for fixing the diaphragm 42 at the tip, is housed and installed. The lever 43
Is in contact with the H-shaped hinge 52 fixed to the piezoelectric actuator 54. Reference numeral 51 is a fulcrum. FIG.
Reference numerals 56, 56a, 56b, and 56c shown therein are bolts.

[0004] A pump section 31b is connected to the driving section 31a. The pump section 31b includes a discharge section including a discharge port 35, a ball guide 36, a check valve 37, a valve seat 38, and an O-ring 39, and an inflow port 46, a ball guide 36a, a check valve 37a, a valve seat 38a and an O Ring 3
9a and a function of sucking and discharging the fluid in the pump chamber by micro-vibration.
2 comprises a diaphragm 42 fixed to the diaphragm 2, a diaphragm holder 45 for supporting the diaphragm 42, and a pump head 40 pressed by a pump head retainer 44.

[0005]

However, the conventional piezoelectric pump 31 has a very large number of components that make up the conventional piezoelectric pump 31 in order to convert the circular motion of the lever 43 of the magnifying mechanism 31c into a linear motion. There was a drawback that it was too much. Specifically, components such as the driving leaf spring 33 and the diaphragm joint 34 were essential.

As shown in FIG. 11, sealing beads 42a, 42b formed on a diaphragm 42 are provided.
Since the sealing surface 40a of the pump head 40 to which the sealing surface 40a contacts is located in the recess 40b where the pump chamber 41 of the pump head 40 is located, there is a disadvantage that the finish polishing for finishing the sealing surface 40a cannot be easily performed.

Further, as shown in FIGS. 11 and 12, since the method of attaching the diaphragm fitting 32 to the diaphragm 42 is performed by insert molding, the cost of the parts constituting the piezoelectric pump 31 increases and the manufacturing cost increases significantly. There was a disadvantage that it would go up.

Therefore, in the piezoelectric pump 1 according to the present invention,
The design is such that the number of parts constituting the piezoelectric pump 1 is reduced as much as possible, and the diaphragm 22 attached to the tip of the enlargement mechanism 31c is installed at the position closest to the direct motion.

Also, sealing beads 42a, 42 projecting from the outer peripheral surface of the surface of the diaphragm 42 are formed.
The shape was such that the sealing surface 40a of the pump head 40 to which b adheres could easily be polished.

It is still another object of the present invention to provide a piezoelectric pump having a diaphragm structure which has a rigidity and is easy to mount, and which is designed to reduce the cost of components.

[0011]

According to the present invention, there is provided a piezoelectric pump for driving a diaphragm by enlarging a displacement of a piezoelectric actuator by a lever to solve the above-mentioned problem.
That the center point of the diaphragm surface is located at one of the point where the circular motion centering on the fulcrum of the lever and the center axis of the donut-shaped disk-shaped diaphragm touches or near the point where the center axis of the diaphragm touches. The configuration of the characteristic piezoelectric pump was adopted.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piezoelectric pump according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a front view of a piezoelectric pump according to the present invention, and FIG. 3 is a right side view of the piezoelectric pump according to the present invention.

The piezoelectric pump 1 according to the present invention comprises a pump body 1a and supporting legs 1b fixed to the pump body 1a by bolts 4. In the pump body 1a, an inflow port 2a into which a fluid flows is formed to protrude downward, and a discharge port 3a for discharging the inflow fluid is formed to protrude upward.

FIG. 2 is a partial longitudinal sectional view of the left side showing the internal structure of the piezoelectric pump according to the present invention, and FIG. 4 is a horizontal cross sectional view showing the internal structure of the piezoelectric pump according to the present invention.
The pump body 1a of the piezoelectric pump 1 according to the present invention includes a driving unit 1c and a pump unit 1d as shown in FIGS.

As shown in FIGS. 2 and 4, the drive unit 1c includes a back plate 20, a U-shaped cover 24a.
And a casing formed of a diaphragm holder 27, a printed wiring board 8 mounted in the casing, and a bolt 4 for supporting a lever 28.
, A piezoelectric spring 21 fixed to the
It comprises a lever 28 bent in a crank shape, a spring 19 having a pulling function, a diaphragm 22 fixed to a diaphragm fitting 23, a diaphragm holder 27 and the like.

The pump section 1d comprises an inflow section 2, a discharge section 3 and a pump chamber 18, as shown in FIGS. The pump chamber 18 includes a pump head 16, a diaphragm holder 27, and a diaphragm 22, and the diaphragm 22 includes the pump head 16 and the diaphragm holder 2.
7 between.

As shown in FIG. 4, the diaphragm 22
One end of the lever 28 is sandwiched by the diaphragm fitting 23 together with the spacer 19b, and the other end of the lever 28 is fixed to the leaf spring 9 by a bolt 4b. Code 26
Indicates a fulcrum of the lever 28.

The center point c of the surface of the diaphragm 22 is located at the point where the center axis b of the diaphragm 22 contacts. Alternatively, the center point c of the diaphragm surface is located near the point where the center axis b of the diaphragm 22 contacts. With such a structure, the diaphragm 2
Numeral 2 makes a motion closest to a linear motion on an arc motion as shown by an arrow a around the fulcrum 26 of the lever 28.

An H-shaped hinge 21a fixed to the piezoelectric actuator 21 is attached to the other end of the lever 28 bent in a crank shape and fixed to the leaf spring 9 so as to come into contact with the lever. A cord 25 from the printed wiring board 8 is connected to the piezoelectric actuator 21 to control the piezoelectric actuator 21.

The printed wiring board 8 is connected to a cord 25a of a power supply cable 7 which is drawn into a holder 5 for holding the cable 7 by tightening a nut 6.

A locking pin 23b is press-fitted into the distal end portion 28a of the lever 28, and the locking pin 23b
A spring 19 for pulling the lever 28
Is locked at one end. The other end of the spring 19 is locked by a locking pin 20 a fixed to the back plate 20.

As shown in FIG. 2, the pump section 1d includes an inflow section 2, a discharge section 3, a pump head 16, a pump chamber 18, and the like. The pump chamber 18 is located between a concave portion formed in the pump head 16 and a concave portion formed in the diaphragm holder 27.
8 is fixed to the pump head 1
The outer periphery of the diaphragm 22 is sandwiched and attached between the diaphragm 6 and the diaphragm holder 27.

Also, as shown in FIG.
The inflow section 2 that flows into the pump chamber 18 includes an inflow port 2a, a tube joint 10a, an inflow side flow path 29, an O-ring 11a,
A ball guide 12 and a check valve 13a are provided below the pump head 16.

The check valve 1 which is guided by the ball guide 12a into the inflow side flow passage 29 communicating with the pump chamber 18 and is a spherical body
3a. Then, the inflow-side flow path 2 having the check valve 13a
9 has a tube joint 10a, and an inflow port 2a is formed below the tube joint 10a.

The discharge section 3 from which the fluid in the pump chamber 18 is discharged
Is a discharge port 3a, a tube joint 10, a discharge side flow path 30,
An O-ring 11, a ball guide 12, and a check valve 13 are provided above the pump head 16.

The check valve 13 which is guided by the ball guide 12 into the discharge side flow path 30 communicating with the pump chamber 18 and is a spherical body
There is. The tube joint 10 is provided in the inflow-side flow path 29 where the check valve 13 is located, and the tube joint 10 is formed with a discharge port 3a.

As described above, the piezoelectric pump 1 of the present invention
As shown in FIG. 4, the lever 28 directly drives the diaphragm 22 by an arc motion as shown by an arrow a, and a mechanism for converting the motion into direct motion is removed. In this case, an arrangement satisfying the following conditions is adopted so that the movement becomes the closest to the linear movement.

That is, the center point of the diaphragm surface is located at or near the point c where the arc line indicated by the arrow a centering on the fulcrum 26 of the lever 28 and the center line b of the diaphragm 22 are in contact. It is characterized by being arranged.

FIG. 5 is an enlarged sectional view of a portion of the piezoelectric pump according to the present invention to which the diaphragm is attached.
As shown in FIG. 5, an inflow-side flow path 29 into which the fluid is sucked and flows into the pump head 16 and a discharge-side flow path 30 which is discharged from the pump chamber 18 and flows out are formed. Pump room 1
8, the inflow side flow path 29 and the discharge side flow path 30 communicate with each other.

The pump chamber 18 is a space surrounded by the diaphragm 22, the diaphragm fitting 23, and the pump head 16, and the outer periphery of the diaphragm 22 is sandwiched between the pump head 16 and the diaphragm holder 27. A diaphragm fitting 23 is fixed to the diaphragm 22, and a projection 19 d of the diaphragm fitting 23 is provided with a spacer 19.
b and the lever 28 are fastened and fixed by the nut 19.

As shown in FIG. 5, the diaphragm 22
Through-hole 22 formed at the center of diaphragm 22
i, the protruding portion 23d of the diaphragm fitting 23 is inserted, the protruding portion 23d is further inserted into the spacer 19b and the lever 28, and the nut 19a is connected to the protruding portion 23 of the diaphragm fitting 23.
d, and the protrusion 23d of the diaphragm fitting 23
It is fixed to.

As described above, in the piezoelectric pump 1 according to the present invention, the diaphragm 22 is made of a rubber diaphragm and the diaphragm fitting 23 is used instead of the conventional structure in which the diaphragm fitting is inserted into the diaphragm.
Is fixed by inserting it into a through hole 22i formed in the center of the diaphragm 22.

The diaphragm 22 used in the piezoelectric pump 1 according to the present invention is a donut-shaped disk-shaped diaphragm. Further, as shown in FIG. 5, the sealing surface 16a of the pump head 16 joined to the diaphragm 22 is formed at a position protruding from the surface 16b of the pump head 16.

FIG. 6 is an enlarged longitudinal sectional view of a diaphragm attached to the piezoelectric pump according to the present invention, and FIG. 7 is an enlarged longitudinal sectional view of a part of the diaphragm shown in FIG.

An outer bead 22a and an inner bead 22b for sealing the pump chamber 18 are formed in a ring shape on the outer peripheral portion of the surface of the diaphragm 22 formed in a donut-shaped disk shape.

A ring-shaped recess 22c is formed between the outer bead 22a and the inner bead 22b projecting from the outer peripheral surface of the diaphragm 22. A recess 22d larger than the recess 22c is formed in a ring shape closer to the inside of the through hole 22i than the inner bead 22b.

Further, on the surface of the diaphragm 22, there is a flat portion which is formed flat near the through hole 22i from the concave portion 22d. After the flat portion 22j, the diaphragm metal fitting 23 and the diaphragm 22 are sealed. The outer small bead 22f and the inner small bead 22h protrude in a ring shape. A concave portion 22g projects in a ring shape between the outer small bead 22f and the inner small bead 22h.

On the back surface of the diaphragm 22, a ridge 22e is provided.
Project in a ring shape. That is, the projection 22 is provided on the back surface opposite to the concave portion 22d formed on the surface of the diaphragm 22.

As shown in FIG. 5, an outer small bead 22f and an inner small bead 22h are tightly joined to an inner surface 23c of a flange 23a of a diaphragm fitting 23 having a T-shaped cross section. Threads for applying the surface pressure of the outer small bead 22f and the inner small bead 22h are formed on the outer peripheral surface of the protrusion 23d. A nut 19a is screwed into the thread.

In order for the tips of the outer small bead 22f and the inner small bead 22h to be in close contact with the inner surface 23c of the flange 23a of the diaphragm fitting 23, the flange 2 of the diaphragm fitting 23 is required.
The outer small bead 22f and the inner small bead 22h are configured to deform by applying a surface pressure to the ring-shaped bead of the inner surface 23c of 3a.

As described above, by pressing the outer small bead 22f and the inner small bead 22h, the inner bead 23f and the inner bead 22h are deformed.
c, the diaphragm 22, the spacer 19b, and the lever 28 are sequentially stacked on the diaphragm fitting 23 and attached to the protrusion 23d, and the nut 19a can be screwed into the diaphragm 22, the spacer 22, the spacer 19b, the lever 28, etc. Are assembled by screwing them so as to sandwich them.

At this time, the diaphragm metal fittings 23, the spacer 19b, and the metal parts of the lever 28 are all tightened with a strong force by tightening the nut 19a so that the diaphragm 22 is not excessively pressed. A step is formed on the outer periphery of the protruding portion 23d to form a stepped structure.

With such a structure, the diaphragm 2
Since it is not necessary to insert the diaphragm fitting 23 into the component 2, the cost of parts can be reduced, the assembling becomes easy, the number of parts can be reduced, and the number of parts can be reduced.

The pump section 1d of the piezoelectric pump 1 according to the present invention.
The sealing surface 16a of the pump head 16 attached to the diaphragm 22 with the diaphragm 22 may not be projected. That is, they may be on the same surface.

The piezoelectric pump 1 according to the present invention may have a structure in which the spacer 19b sandwiching the diaphragm 22 and the diaphragm fitting 23 is formed integrally with the lever 28.

In the piezoelectric pump 1 according to the present invention, the diaphragm 22 is clamped by tightening the male screw of the projection 23d of the diaphragm fitting 23 and the nut 19a, but the diaphragm 22 is directly connected to the lever 28 without using the nut 19a. A female screw may be formed and a diaphragm fitting may be screwed in.

Further, a female screw may be formed in the diaphragm fitting 23 itself and tightened by using a bolt which is a male screw.

As a sealing method, a bead for sealing is formed on the diaphragm 22, but the bead is formed on the seal surface of the pump head 16 and the seal surface of the diaphragm fitting without forming a bead on the diaphragm 22. You may.

[0049]

Since the present invention has the above-described configuration, the following effects can be obtained. In other words, the piezoelectric pump according to the present invention has a rigidity and a structure in which the diaphragm attached to the tip of the enlarging mechanism of the driving unit is installed at a position closest to the direct movement, so that the sealing surface of the diaphragm can be easily polished. Since the diaphragm structure is easy to mount, the number of parts is extremely small compared to the conventional piezoelectric pump, and the design is easy. The processing cost of the parts is reduced, and the number of assembling steps is reduced, so that the manufacturing cost can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a piezoelectric pump according to the present invention.

FIG. 2 is a left side sectional view showing the internal structure of the piezoelectric pump according to the present invention.

FIG. 3 is a right side view of the piezoelectric pump according to the present invention.

FIG. 4 is a cross-sectional plan view showing the internal structure of the piezoelectric pump according to the present invention.

FIG. 5 is an enlarged sectional view of a portion of the piezoelectric pump according to the present invention to which a diaphragm is attached.

FIG. 6 is an enlarged vertical sectional view of a diaphragm attached to the piezoelectric pump according to the present invention.

FIG. 7 is a partially enlarged longitudinal sectional view of a diaphragm attached to the piezoelectric pump according to the present invention.

FIG. 8 is a front view of a conventional piezoelectric pump.

FIG. 9 is a longitudinal sectional view showing the internal structure of a conventional piezoelectric pump.

FIG. 10 is a plan view showing the internal structure of a conventional piezoelectric pump.

FIG. 11 is an enlarged vertical sectional view of a diaphragm portion attached to a conventional piezoelectric pump.

FIG. 12 is an enlarged vertical sectional view of a diaphragm attached to a conventional piezoelectric pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric pump 1a Pump main body 1b Support leg 1c Drive part 1d Pump part 2 Inflow part 2a Inflow port 3 Discharge part 3a Discharge port 4 Bolt 5 Retraction cylinder 6 Tightening nut 7 Cable 8 Printed wiring board 9 Leaf spring 10 Tube joint 11 O Ring 12 Ball guide 12a Ball guide 13 Check valve 14, 14a Bolt 15 Valve seat 16 Pump head 16a Seal surface 17 Bolt 17a Bolt 18 Pump chamber 19 Spring 19a Nut 19b Spacer 20 Back plate 21 Piezoelectric actuator 21a H-type hinge 22 Diaphragm 22a Outer bead 22b Inner bead 22c, 22d Recess 22e Ridge 22f Outer small bead 22g Recess 22h Inner small bead 22i Through hole 22j Flat portion 23 Diaphragm fitting 23a Flange 23b Lock pin 23c Inner surface 23d Projecting portion 24 Bottom plate 24a Cover 25, 25a Cord 26 Supporting point 27 Diaphragm holder 28 Lever 28a Tip 29 Inflow-side flow path 30 Discharge-side flow path 31 Conventional piezoelectric pump 31a Drive unit 31b Pump unit 31c Enlargement mechanism 32 Diaphragm fitting 33 Drive plate Spring 34 Diaphragm joint 35 Discharge port 36 Ball guide 37 Check valve 38 Valve seat 39 O-ring 40 Pump head 40a Seal surface 40b Depression 41 Pump chamber 42 Diaphragm 42a, 42b Bead for sealing 43 Lever 44 Pump head presser 45 Diaphragm holder 46 Inflow port 47 Spring 48 Cover 49 Back plate 50 Bottom plate 51 Support point 52 H-shaped hinge 53 Lever support leaf spring 54 Piezoelectric actuator 55 Printed wiring board 56 to 56c Bolt

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideki Abe 1-13-6, Minakugahara, Ota-ku, Tokyo F-term in Nippon Keiki Seisakusho Co., Ltd. 3H075 AA01 BB04 CC32 CC33 CC35 DA05 DB02 DB34 3H077 AA01 CC02 DD06 EE34 EE35 EE37 FF09 FF36 FF39 FF42

Claims (3)

[Claims] 1. A piezoelectric pump 1 for driving a diaphragm by enlarging the displacement of a piezoelectric actuator with a lever,
A piezoelectric pump characterized in that the center point of the diaphragm surface is located at one of a point where the circular motion centered on the fulcrum of the lever contacts the center axis of the diaphragm or near a point where the center axis of the diaphragm touches. . 2. The piezoelectric pump according to claim 1, wherein a sealing surface of the pump head to be joined to the diaphragm is formed at a position protruding from a surface of the pump head. 3. An outer bead for sealing with a pump head and an inner bead are provided on the outer peripheral portion of the surface of the donut-shaped disk-shaped diaphragm, and a diaphragm fitting for fixing to the driving portion is provided on the inner peripheral portion of the surface. 2. The piezoelectric pump according to claim 1, wherein an outer small bead and an inner small bead are provided for sealing.