JPH0350300Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The invention uses a vibrator that uses a piezoelectric ceramic plate that generates distortion when a voltage is applied to alternately increase and decrease the volume of the pump chamber to increase or decrease the volume of fluid sucked in from the suction port. The present invention relates to a piezo pump configured to discharge fluid from a discharge port, and particularly to a piezo pump suitable for use in pumping conductive fluid.

Problems to be solved by conventional techniques and ideas Piezo pumps, especially piezo pumps used for pumping conductive fluids, elongate the surface of a thin metal plate in the direction along the surface by applying an alternating voltage. A pump chamber is formed by stretching a piezoelectric ceramic plate, which is made of a piezoelectric ceramic plate with an electrode coating formed on both the front and back sides with adhesive, which alternately shrinks and shrinks, over a hole formed in the pump chamber. By connecting the electrode coating on the front side of the plate and the thin metal plate that is conductive to the electrode coating on the back side to an AC power source, and applying an AC voltage to the piezoelectric ceramic plate, the vibrator is alternately bent inward and outward. The volume of the pump chamber is alternately increased and decreased so that the fluid sucked in from the suction port is discharged from the discharge port. At the same time, a metal It has a structure in which an insulating film is attached to the surface of the thin plate facing the pump chamber.

However, in conventional piezo pumps, the vibrator has a structure in which a piezoelectric ceramic plate is attached to a thin metal plate with adhesive, and the hardness of the adhesive changes depending on the temperature, causing the thin metal plate and piezoelectric Since the amount of slippage that occurs between the ceramic plates changes, even if the piezoelectric ceramic plate expands and contracts by a certain amount, the amount of deflection of the thin metal plate changes, causing variations in the flow rate of the fluid. The coefficient of thermal expansion of the metal sheet and the hardness of the insulating film also change, and these also change the amount of deflection of the thin metal plate, causing variations in the flow rate of the fluid. Furthermore, as for measures to prevent electric leakage, insulating films are not always sufficient because pinholes are easily formed.

Means for Solving the Problems As a means for solving the above problems, the piezo pump of the present invention is made by laminating multiple piezoelectric ceramic plates that expand and contract in the direction along the surface when an alternating current voltage is applied. A pump chamber is formed by extending the vibrator over a hole formed in the pump body, and insulates the piezoelectric ceramic plate of the innermost layer of the vibrator facing the pump chamber from the AC power source. The piezoelectric ceramic plates other than the innermost piezoelectric ceramic plate are connected to an AC power source, and the vibrator is alternately bent inward and outward by application of an AC voltage, thereby alternately increasing and decreasing the volume of the pump chamber. The structure is such that the fluid inhaled through the mouth is discharged from the discharge port.

Functions and Effects The present invention has the above configuration, and when an alternating current voltage is applied to the piezoelectric ceramic plates other than the innermost piezoelectric ceramic plate facing the pump chamber of the vibrator made of a plurality of laminated piezoelectric ceramic plates, As the piezoelectric ceramic plate expands and contracts in the direction along the surface, the vibrator alternately expands and flexes outward, and concave and flex inward, which alternately increases and decreases the volume of the pump chamber. Then, the fluid sucked in from the suction port is discharged from the discharge port, and the fluid is completely cut off from the AC power source by the piezoelectric ceramic plate in the innermost layer. Because of its structure, unlike conventional vibrators in which a piezoelectric ceramic plate is bonded to a thin metal plate with adhesive, the curing state of the adhesive changes with changes in temperature, and the coefficient of thermal expansion of the thin metal plate changes due to changes in temperature. Furthermore, the amount of deflection is always constant without being affected by changes in the hardness of the insulating film for preventing leakage, making it possible to stabilize the flow rate of the fluid, and also to stabilize the flow rate of the fluid. By using the inner layer piezoelectric ceramic plate as an insulator,
Unlike conventional insulating films, there is no risk of pinholes occurring, and complete insulation can be achieved, which has the effect of reliably preventing electrical leakage accidents.

Embodiment Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 3.

In the figure, reference numeral 1 denotes a frame made of synthetic resin constituting the pump body, and the inner circumference is formed into a circular shape. 2 is provided around the frame 1, and a fluid inlet 5 and a fluid outlet 6 each equipped with a check valve 4 are formed on both sides sandwiching the center of the outer circumferential surface of the frame 1.
The frame 1 is connected by the communicating holes 7, 7 formed in the collar 2, respectively.
It is connected to the inner circumferential side.

A pair of disc-shaped oscillators 9, 9 are stretched on both the upper and lower surfaces of the flange 2, and this oscillator 9
consists of two piezoelectric ceramic plates 10, 10 that expand and contract in the radial direction when an alternating current voltage is applied.
An internal electrode layer 11 is placed between both piezoelectric ceramic plates 10.
The outer electrode layers 12 and 12 are laminated and integrally bonded to the outer surfaces of both piezoelectric ceramic plates 10, respectively, as shown in FIGS. 2 and 3. The peripheral edge portion of the external electrode layer 12 is removed, and a connection portion 13 is connected to the internal electrode layer 11 through a connecting portion 14 welded in a hole 10a extending from the front surface to the back surface of the outer piezoelectric ceramic plate 10. A conductive layer 15 that conducts electrically is formed,
The outer periphery of this vibrator 9 is applied to both upper and lower surfaces of the collar 2 via an O-ring 17, and a press ring 18 made of synthetic resin is applied to the outer side of the O-ring 17. The vibrators 9, 9 are stretched by fastening 19 with a fastener (not shown), and a pump chamber 20 is formed between both vibrators 9.

The external electrode layer 12 on the surface of the piezoelectric ceramic plate 10 on the outside of each vibrator 9 is attached to one of the pair of electrode rods 22, 22 connected to the AC power supply 21 installed in the frame 1, and the external electrode layer 12 is attached to the other side. Conductive layer 15 of each vibrator 9
are connected by lead wires 24 and 25, respectively,
A piezoelectric ceramic plate 10 inside each vibrator 9 is insulated from an AC power source 21.

This embodiment has the above structure, and the electrode rods 22, 2
2 is connected to an AC power source 21 and an AC voltage is applied to the piezoelectric ceramic plate 10 on the outside of both vibrators 9. As the piezoelectric ceramic plate 10 on the outside repeats expansion and contraction in the radial direction, both vibrators 9, 9 alternately swell and bend outward and dent and bend inward, thereby alternately increasing and decreasing the volume of the pump chamber 20, and the fluid sucked into the pump chamber 20 from the suction port 5 is discharged. The external electrode layer 12 on the surface of the piezoelectric ceramic plate 10 inside both vibrators 9 is not connected to the AC power supply 21, and the inner piezoelectric ceramic plate 10 functions as an insulator. Therefore, the fluid flowing through the pump chamber 20 is electrically isolated from the AC power source 21.

4 and 5 show other embodiments. In the example in FIG. 4, the vibrator 29 is made of three piezoelectric ceramic plates 3.
0, internal electrode layers 31, 31 between each piezoelectric ceramic plate 30, outer and inner piezoelectric ceramic plates 3
The outer electrode layer 32 on the surface of the piezoelectric ceramic plate 30 is connected to one terminal of the AC power source 21 and the lead wire 34 is connected to one terminal of the AC power source 21. The internal electrode layer 31 between the middle and inner piezoelectric ceramic plates 30 is connected to the other terminal with a lead wire 35, and when an alternating current voltage is applied, the outer and middle piezoelectric ceramic plates 30 By expanding and contracting together in the radial direction, the entire vibrator 29 including the inner piezoelectric ceramic plate 30 bends inward and outward to vibrate, and the inner piezoelectric ceramic plate 30 functions as an insulator. Furthermore, the example in FIG. 5 has a three-layer vibrator 2 similar to the example in FIG.
9 is used to connect the external electrode layer 3 on the surface of the outer piezoelectric ceramic plate 30 to one terminal of the AC power source 21.
2 and the internal electrode layer 31 between the middle and inner piezoelectric ceramic plates 30 are connected with lead wires 36 and 37, respectively, and the internal electrode layer 31 between the outer and middle piezoelectric ceramic plates 30 is connected to the other terminal. They are connected by lead wires 38, and when an alternating current voltage is applied, the outer and middle piezoelectric ceramic plates 30 expand and contract in opposite directions, causing the outer and middle piezoelectric ceramic plates 30 to bend inward and outward. As a result, the entire vibrator 29 including the inner piezoelectric ceramic plate 30 bends inward and outward to vibrate, and the inner piezoelectric ceramic plate 30 functions as an insulator. Since the outer and middle piezoelectric ceramic plates 30 have a structure in which they expand and contract oppositely to each other, there is an advantage that the amount of deflection of the vibrator 29 can be increased.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a perspective view of the vibrator, FIG. 3 is a sectional view showing the connection between the vibrator and the AC power supply, and FIGS. FIG. 5 is a sectional view showing a connection state between a vibrator and an AC power source according to other embodiments. 1: Frame (pump body), 2: Tsuba, 5: Suction port,
6: Discharge port, 9: Vibrator, 10: Piezoelectric ceramic plate, 11: Internal electrode layer, 12: External electrode layer, 1
5: Conduction layer, 20: Pump chamber, 21: AC power supply,
29: Vibrator, 30: Piezoelectric ceramic plate, 31:
Internal electrode layer, 32: external electrode layer.

Claims (1)

[Scope of utility model registration request] A pump chamber is formed by stretching a vibrator made of a plurality of laminated piezoelectric ceramic plates that expand and contract in the direction along the surface when an alternating current voltage is applied, over a hole formed in the pump body, and the vibration The innermost layer piezoelectric ceramic plate facing the pump chamber of the child is insulated from the AC power source, and the piezoelectric ceramic plates other than the innermost layer piezoelectric ceramic plate are connected to the AC power source, and the vibrator is activated by applying an AC voltage. A piezo pump characterized in that the fluid sucked in from the suction port is discharged from the discharge port by alternately increasing and decreasing the volume of the pump chamber by alternately deflecting the pump chamber inward and outward.