JPH03149370A - Piezoelectric vibrator and piezoelectric type pump therewith - Google Patents

Abstract

PURPOSE:To secure a stable vibro-characteristic and perform an effective fluid transfer with this characteristic by making a holding member support the more outside than the peripheral edge of an elastic plate and setting a distance from an elastic plate center to the elastic plate peripheral edge and a distance from the elastic plate center to a holding member supporting point to the specified relationship. CONSTITUTION:In a piezoelectric pump, an elastic plate 8 of a piezoelectric vibrator 7 is supported free of elastic deformation in using seal rings 12, 13 of a mold body 11 as supporting points via this mold body 11, and such a supporting structure as setting a distance R1 from the center of the elastic plate 8 to the peripheral edge and a distance R2 from the center of the elastic plate 8 to each supporting point of the seal rings 12, 132 to a relationship of (R2-R1)/R2=0.05 - 0.3, if possible 0.1 - 0.15 is adopted. With this constitution, assuming that the piezoelectric vibrator 7 is the same magnitude, it vibrates with amplitude in a large range which is impossible to secure in any other supporting structure. Moreover, this large amplitude is thus stably maintainable.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a piezoelectric vibrator and a piezoelectric pump using the same.

(Prior Art) Recently, pumps employing piezoelectric elements are being used, for example, as pumps for liquid transfer. A pump that uses this piezoelectric element has a part of the pump chamber that communicates with the suction port and the discharge port that is made up of a piezoelectric vibrating body made by superimposing a piezoelectric element on an elastic plate. By applying an alternating voltage to the elastic plate, the elastic plate vibrates, and depending on the direction of the vibration, fluid is sucked into the pump chamber from the suction port, and the fluid is further pressurized and discharged from the discharge port.

This piezoelectric pump has low power consumption and is compact, making it suitable for relatively small capacity pumps.

However, conventional piezoelectric pumps have a problem in that when operated under the conditions of maximum fluid transfer characteristics, the amount of fluid transferred per unit time is unstable and the transfer characteristics may become unstable. .

The above problems are not limited to piezoelectric pumps, but also to piezoelectric vibrators in general. The problem is that vibration characteristics such as vibration variation become unstable.

(Problems to be Solved by the Invention) As described above, the conventional piezoelectric pump has unstable transfer characteristics and cannot transfer fluid effectively.

Furthermore, the vibration characteristics of a single piezoelectric vibrator may be unstable, making it impossible to utilize the piezoelectric vibrator effectively.

The present invention was made based on the above circumstances, and an object of the present invention is to provide a piezoelectric pump for transferring.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to achieve the above object, the piezoelectric vibrating body of the present invention has a piezoelectric vibrating body in which a piezoelectric element is superimposed on an elastic plate. A holding member is provided at the periphery, and this holding member is supported at a location outside the periphery of the elastic plate, and the distance R1 from the center of the elastic plate to the periphery of the elastic plate and the distance R1 from the center of the elastic plate to the support point of the holding member are Distance 1itIR2, (R2-R1:1
/R2=0.05 to 0.3.

Furthermore, in order to achieve the above object, a piezoelectric pump using the piezoelectric vibrating body of the present invention has a piezoelectric pump in which a piezoelectric element is superimposed on an elastic plate in a part of the pump chamber that communicates with the suction port and the discharge port. In this pump, a holding member is provided at the periphery of an elastic plate, and this holding member is supported at a portion outside the periphery of the elastic plate, In addition, the distance R1 from the center of the elastic plate to the periphery and the distance R2 from the center of the elastic plate to the support point of the holding member are (R2-RL)/R2=0.05 to 0.
．． It is characterized by having a relationship of 3.

The inventor of the present invention has repeatedly researched the vibration characteristics of piezoelectric vibrators, for example, the fluid transfer characteristics of piezoelectric pumps. It turned out that this was due to the fact that this was not done properly.

It was also found that the reason why the vibration characteristics of the piezoelectric vibrating body are not sufficient as described above is due to the structure that supports the piezoelectric vibrating body. In other words, in conventional piezoelectric pumps, the piezoelectric element is superimposed on an elastic plate larger than the piezoelectric element, and the periphery of this elastic plate is supported to vibrate the entire piezoelectric vibrating body. It was found that the vibrating body could not be vibrated with a sufficiently large amplitude, and that the vibration was unstable.

Instead of this conventional support structure, the inventor provided a holding member on the periphery of the elastic plate of the piezoelectric vibrator as a new support structure that can stably vibrate the piezoelectric vibrator with a large amplitude. We have discovered a structure in which the holding member is supported at a location outside the peripheral edge of the elastic plate by utilizing the following. That is, in this support structure, by setting the distance from the periphery of the elastic plate to the holding member support point to a predetermined size with respect to the radius of the elastic plate, the piezoelectric vibrating body can be stably vibrated with a large amplitude. I discovered that it can be done.

The present invention has been made based on this knowledge.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the piezoelectric pump of the present invention using the piezoelectric vibrator of the present invention.

In the figure, 1 is a circular base, and 2 is a circular force bar that is combined and provided above the base. force bar 2
A suction port 3 and a discharge port 4 are respectively provided in the earthen wall, and a suction valve 5 and a discharge valve 6 are provided in the suction port 3 and the discharge port 4, respectively.

A piezoelectric vibrator 7 is provided between the base 1 and the force bar 2. This piezoelectric vibrating body 7 is constructed by joining piezoelectric elements 9 and 10, each of which is a disk with a smaller diameter, on both sides of a metal elastic plate 8 that is a disk.

Further, the piezoelectric vibrating body 7 is molded with a molded body 11 made of a soft synthetic resin having electrical insulation and elasticity, and is disposed inside the molded body 11. This molded body 11 has a disk shape with a larger diameter than the piezoelectric vibrating body 7,
It has a diameter that can stably support the piezoelectric vibrating body 7, and a thickness that allows the molded body itself to have good elasticity without hindering the vibration of the piezoelectric vibrating body 7. The periphery of the molded body 11 also serves as a holding member that holds the periphery of the piezoelectric vibrating body 7 therebetween. Annular seal rings 12 and 13 are integrally formed on both side surfaces of the peripheral edge of the molded body 11, that is, the holding member portion, and are located outside the peripheral edge of the elastic plate 8 of the piezoelectric vibrating body 7, respectively. be. The seal rings 12 and 13 are formed around the entire circumference of the molded body 11 with a radius R2 larger than the radius R1 from the center O to the periphery of the elastic plate 8, with the center 0 of the elastic plate 8 of the piezoelectric vibrating body 7 as the center. It has a semicircular cross section. The radius R2 has a relationship of (R2-RI)/R2 of 05 to 3, preferably 0.1 to 0.15.
The size is set to .

On the other hand, a circular recess 14 is formed in the base. An annular groove 7516 having a semicircular cross section is formed on the bottom surface of the recess 14, and an annular groove 15 facing the groove 16 of the base 1 is formed on the bottom surface of the force bar 2. and,
The molded body 11 surrounding the piezoelectric vibrating body 7 is located in the recess 1 of the base 1.
4, and by combining the force bar 2 with the base 1, the force bar 2 is sandwiched between the base 1 and the force bar 2. Here, one seal ring 12 of the molded body 11 is fitted into the groove 15 of the force bar 2, and the other seal ring 13 is fitted into the groove 16 of the base 1.

The sealing rings 12 , 13 thereby seal between the mold body 11 and the force bar 2 and between the mold body 1 ] and the base 1 . In addition, the seal ring 1 of the mold body 11
2.13 is applied with force from the force bar 2 and the base 1 to press the mold body 11 from both sides. That is, the seal rings 12 and 13 support the molded body 11 at a position outside the periphery of the elastic plate 8 of the piezoelectric vibrating body 7. In other words, the seal rings 12 and 13 support the holding member provided on the periphery of the elastic plate 8 of the piezoelectric vibrating body 11 at a position outside the periphery of the elastic plate 8. A pump chamber 17 is constituted by the force bar 2 and the molded body 11 of the piezoelectric vibrating body 7.

Note that an air vent hole 18 is formed at the bottom of the base 1.

The suction 3 and discharge port 4 of the force bar 2 are connected to a pipe (not shown) through which fluid flows.

The operation of the piezoelectric pump configured in this way will be explained with reference to FIG. 2 as well.

In the piezoelectric vibrating body 7, the piezoelectric elements 9.10 are polarized at right angles to the elastic plate 8, and the piezoelectric elements 9.10 and the elastic plate 8 are connected to an alternating current power source AC as a common as shown in FIG. has been done. When an AC voltage is applied from the AC power supply AC to the elastic plate 8 and the piezoelectric element 9.10 of the piezoelectric vibrating body 7, the piezoelectric cords 9.10 sandwiching the elastic plate 8 are displaced in opposite directions.
The elastic plate 8 also elastically deforms and curves accordingly. As a result, the entire piezoelectric vibrating body 7 curves and vibrates as shown by the imaginary line in the figure. Therefore, the molded body 11 is elastically deformed and curved using the seal ring 12.13 as a fulcrum in the same manner as the piezoelectric vibrating body 7. That is, the piezoelectric vibrating body 7 is the elastic plate 8
The seal rings 12 and 13 are elastically deformed, curved, and vibrated through the molded body 11 that holds the peripheral edges of the seal rings 12 and 13 as fulcrums. Then, as the piezoelectric vibrating body 7 alternately repeats this operation in accordance with the cycle of the AC voltage, the piezoelectric vibrating body 7 and the molded body 11 repeat vibrations using the seal rings 12 and 13 as fulcrums.

When the piezoelectric vibrating body 7 and the molded body 11 are deformed toward the base 1 side, external fluid is sucked into the pump chamber 17 from the suction port 3, and conversely, the piezoelectric vibrating body 7 and the molded body 1
When the pump 1 is deformed toward the cover 21, the fluid in the pump chamber 17 is discharged from the discharge port 4 to the outside.

However, in this piezoelectric pump, the mold material 1
The elastic plate 8 of the piezoelectric vibrating body 7 is supported elastically deformably through the molded body 11 using the seals 12 and 13 of 1 as a support point, and the distance R1 from the center of the elastic plate 8 to the periphery and the elastic plate 8
The distance R2 from the center of the seal ring 12.13 to the support point (seal ring center point) is (R2-R1)
/R2=0.05-063, preferably 0.1-0.
15, and the piezoelectric vibrating body 7 vibrates with a wide amplitude that cannot be obtained with other support structures of the same size.

Moreover, this large amplitude vibration can be stably maintained.

FIG. 3 shows the relationship between the magnitude of (R2-R1)/R2 and the amplitude of vibration of the piezoelectric vibrating body 7, when the diameter of the elastic plate 8 of the piezoelectric vibrating body 7 is 35a+m. I'm taking this as an example. According to this diagram, (R2-R1)/R2
is in the range of 0.05 to 0.3, especially 0.1 to 0.
15, it can be seen that the amplitude of the piezoelectric vibrator 7 is large.

FIG. 4 shows the diameter of the elastic plate 8 of the piezoelectric vibrating body 7 to be 35111.
1, and the (R2-R1)/R2(7) value is 0. 1 and 0.101 are diagrams showing the relationship between capacity and pressure in a piezoelectric pump.

This diagram also shows that stable pump characteristics can be obtained by setting the dimensions so that the value of (R2-R1)/R2 falls within the above range.

Furthermore, in this embodiment, the piezoelectric vibrating body 7 is entirely molded with the mold body 11, so that the piezoelectric vibrating body 7 can be prevented from being corroded by the fluid transferred by the piezoelectric pump. In addition, the piezoelectric vibrating body 7 is connected to an AC power source p, c i,:
The electrically connected portion can be insulated from the fluid. Seal ring 12.1 integrated into mold body 11
3, the support point of the mold body 11 by the seal ring is fixed. A highly accurate support structure can be obtained by preventing shifts in support points due to errors in component dimensions or assembly dimensions. The mold body 11 is made of a soft resin material in order to have elasticity, but by forming the seal ring 12.1B integrally with the mold body 11, the shield ring 12.13 can be attached to the mold body 1.
1 can be made of the same soft material. Therefore, the shield rings 12, 13 do not press the mold body 11 and crush the support portion of the mold body 11, thereby preventing any adverse effect on the elastic deformation.

In the embodiment described above, the mold body 11 is provided with a seal ring 12.
13 is formed integrally with the force bar 2 and the base. However, as shown in FIG. 115. in the groove 15.16 formed in 1. It is also possible to adopt a configuration in which the molded body 11 is supported at the same time.

In addition, in the embodiments shown in FIGS. 1 and 5, the entire piezoelectric vibrating body is molded with the mold body 11, but the structure is not limited to this, and as shown in FIGS. 6 and 7, Alternatively, a holding member 9 made of synthetic resin and having an annular U-shaped cross section may be attached to the peripheral edge of the elastic plate 8 of the piezoelectric vibrating body 7 by one step such as adhesive bonding. this/! ? The use of the piezoelectric vibrator of the present invention is not limited to piezoelectric pumps, and is not equally limited to any device that utilizes a piezoelectric vibrator.

[Effects of the Invention] As explained above, according to the piezoelectric vibrating body of the present invention and the piezoelectric pump using the same, the periphery of the elastic plate of the piezoelectric vibrating body is supported by the holding member, and this holding member is supported by the elastic plate. The piezoelectric vibrator is supported at a location outside the periphery, and the distance from the center of the elastic plate to the periphery and the distance from the center of the elastic plate to the support point of the holding member are set in a predetermined relationship, so that the piezoelectric vibrator has a sufficiently large amplitude. This makes it possible to stably perform vibrations, and even when used as a pump, fluid can be transferred effectively and stably, and high pump characteristics can be exhibited.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, FIG. 1 is a sectional view showing a piezoelectric pump, FIG. 2 is a diagram showing the electrical configuration and vibration state of a piezoelectric vibrator, and FIG. is a diagram showing the relationship between the position of the support point of the piezoelectric vibrator and the piezoelectric vibration -〇T The position of the support point of the piezoelectric vibrator and the bomb characteristics of the piezoelectric pump. FIG. 3 is a sectional view showing another embodiment of the invention. 1...Base, 2...Power bar, 3-Suction port, 4...
・Discharge port, 7...-piezoelectric vibrator, 8... elastic plate, 9.
10... Piezoelectric element, 11... Mold body, 12.1
3... Seal ring. Applicant's representative Patent attorney Takehiko Suzue ~ Issun (1 "7"-Hill / Spear -\2. Hitting the box 1 Mechi Korozuke)

Claims (1)

[Claims] (1) In a piezoelectric vibrator formed by superimposing a piezoelectric element on an elastic plate, a holding member is provided at the periphery of the elastic plate, the holding member is supported at a portion outside the periphery of the elastic plate, and has an elastic The distance R1 from the center of the plate to the periphery of the elastic plate and the distance R2 from the center of the elastic plate to the support point of the holding member are (R2-R
1) A piezoelectric vibrating body characterized by having a relationship of /R2=0.05 to 0.3. (2) A pump in which a part of the pump chamber that communicates with the suction port and the discharge port is composed of a piezoelectric vibrating body made by superimposing a piezoelectric element on an elastic plate, and sucks in and discharges fluid by the vibration of this piezoelectric vibrator. , a holding member is provided at the peripheral edge of the elastic plate of the piezoelectric vibrating body, and this holding member is supported at a location outside the peripheral edge of the elastic plate, and the distance R1 from the center of the elastic plate to the peripheral edge of the elastic plate and the center of the elastic plate are The distance R2 from to the holding member support point is (R2-R1)
A piezoelectric pump characterized by having a relationship of /R2=0.05 to 0.3.