JP3398801B2 - Micro pump - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm type micropump which performs a pump operation by bending vibration of a diaphragm to which a piezo vibrator is attached. 2. Description of the Related Art Generally, as shown in FIGS. 6 and 7, a diaphragm type micropump has a ceramic plate 2 on which a piezoelectric vibrator 1 is mounted as a diaphragm 3 which can bend and vibrate back and forth. As in the upper case 9
1 ′ and the lower case 92 ′.
An orifice 4 is opened in the diaphragm 3, a suction port 6 and a discharge port 7 are provided in a chamber 5 in front of the diaphragm 3, and a pump chamber 8 is formed on the rear surface of the diaphragm 3 as a pump chamber 8. The operation is configured to be performed. Conventionally, in this type of micropump, although not specifically shown, Li connected to the piezoelectric vibrator 1
The lead wire is drawn out in a direction perpendicular to the piezoelectric vibrator 1. [0004] In the conventional micropump, in particular,
If the soldered part of the positive side lead wire connection of the piezo vibrator 1 in the movable part is in contact with the inner wall of the case at a negative potential, the pump operation is stopped due to an electrical short circuit.
The diaphragm 3 and the upper case 91 taking sufficient intervals between 'intervals Oyo <br/> Beauty lower casing 92 and the inner wall of the' inner wall of the soldering portion is prevented from contact with the casing inner wall. A problem to be solved is that in a conventional micropump, a lead wire connected to the piezoelectric vibrator 1 is drawn out in a direction perpendicular to the piezoelectric vibrator 1. Therefore, the lead wire must be soldered to the piezo vibrator 1 in a bent state, and the connection by the soldering is weak against pulling of the lead wire . The tension caused by the lead wire acts in the direction of vibration of the diaphragm 3 to hinder the vibration and lowers the pump characteristics. In addition, the tension cannot be made uniform during manufacturing, and the pump characteristics vary. Is caused. In particular, when this micropump is used in a flow path having a large load resistance, the magnitude of the amplitude of the piezoelectric vibrator 1 at resonance greatly affects the discharge performance of the pump, and the vibration of the diaphragm 3 due to the tension of the lead wire . Restraint becomes a problem.
In addition, it is difficult to quantify the influence of the tension of the lead wire on the vibration of the diaphragm 3 due to its manufacture, and it is measured as variations in pump discharge performance and variations in electrical characteristics such as resonance impedance and resonance frequency. Is done. [0008] Conventionally, a lead is used in a pump case.
Although the wire is pulled out to the outside with the wire slackened, the stress applied to the diaphragm 3 is reduced as much as possible. However, this alone is not so effective, and the micropump has enough space to slack the lead wire. There is no. In the conventional micropump, in particular,
Since the distance between the diaphragm 3 and the inner wall of the lower case 92 'is large, the pump as a whole is correspondingly large, and the pump chamber 8 is large, so that a sufficient cavity pressure cannot be obtained. Inferior ability. In the case where the conventional micropump is used in a semiconductor type ultra-miniaturized gas rate sensor for electrically detecting a deflection state of a gas flow generated when an angular velocity acts on a sensor main body, particularly, The following problems arise. That is, as shown in FIG.
6 and a gas passage 18 provided with heat wire pairs 171 and 172 therein, a sensor main body 19 is formed by etching a semiconductor substrate, and as shown in FIG. After connecting the micropump 20, the entirety is installed in a package 21 in which gas is sealed, and the gas is ejected from the nozzle hole 16 by driving the micropump 20 to form the gas passage 1.
In the semiconductor type ultra-miniaturized gas rate sensor having an open flow path for generating a gas flow in the nozzle 8, the diameter of the nozzle hole 16 is small and the load conductance at that portion is 10 ² to 10 ³ ( cm ³ / S)
With the limited pumping capability of the conventional micropump 20, it becomes difficult to increase the differential pressure in the flow path, and a sufficient gas flow rate cannot be obtained. According to the present invention, there is provided a piezoelectric vibrator.
Of the lead wire does not corrode the inner wall of the case
While securing the space for that part,
Make the distance between the ram and the inner wall of the lower case as small as
Increase the cavity pressure in the pump chamber and reduce the overall size
To the lead wire connection of the piezo oscillator.
Each of the upper case and lower case
When the two cases are combined, the concave groove
Are facing each other to accommodate the lead wire connection.
An interval is formed . The present invention relates to a piezoelectric vibrator.
Make the connection part of the lead wire strong against pulling
And the tension caused by the lead wire
The pump characteristics by impeding the vibration of
To ensure that the characteristics do not vary.
Lead wire connected to the piezoelectric resonator is parallel to the diaphragm
To the outside . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a micropump according to the present invention, as shown in FIGS. 1 to 5, the pump case is divided into an upper case 91 and a lower case 92. After being fitted in the lower case 92, the two parts are integrally joined by tightening a plurality of parts with screws (not shown). In the figure,
Reference numeral 12 denotes a screw hole for joining. Reference numeral 13 denotes a screw hole for mounting the micropump. Thus, the upper case 91 and the lower case 9
Since the joining with the case 2 is performed by tightening with screws, the processing accuracy of both cases is not so required as compared with the case where joining means by press fitting, screwing, or the like is used, which is suitable for mass production. The edge of the ceramic plate 2 is formed as a diaphragm 9 so that the ceramic plate 2 on which the piezo vibrator 1 is mounted can bend and vibrate back and forth.
The orifice 4 is opened in the diaphragm 3, and a plurality of suction ports 6 are provided on the side of the chamber 5 on the front surface of the diaphragm 3. Further, a discharge port 7 is provided in front of each of them, and a pump operation is performed by bending vibration of the diaphragm 3 with a back surface of the diaphragm 3 as a pump chamber 8. Note that the discharge port 7 is provided at a position facing the orifice 4. The diameter of the orifice 4 is set to be smaller than that of the discharge port 7. In this case, the diameter of the suction port 6 is made larger than that of the discharge port 7 so that a sufficient pump pressure can be discharged into the open flow path having a relatively large load resistance. Also, a part of the discharged pump pressure is prevented from leaking from the suction port 6 as much as possible. A plurality of suction ports 6 having a smaller diameter than the discharge port 7 are provided so that sufficient suction can be performed even if the diameter of the suction port 6 is smaller than that of the discharge port 7. The total area is set to be larger than the area of the discharge port 7. In the present invention, in the present invention, as shown in FIGS. 1 and 3, a hole 14 for drawing out a lead wire is formed in a side surface of the upper case 91, and the piezo is passed through the hole 14. A lead wire 10 connected to the vibrator 1 is drawn out to the outside in parallel with the diaphragm 3. Thus, the lead wire 10 can be easily and reliably soldered to the piezo vibrator 1 with the tip end extended, and the connection state by the soldering is strong against the pulling of the lead wire 10. It will be. Since the tension of the lead wire 10 acts in a direction different from the vibration direction of the tire flam 3, the vibration is hardly obstructed, and sufficient pump performance can be exhibited. Also, structurally, the lead wire 10
As a result, a state in which the tension is most stable can be obtained, the tension at the time of pulling out the lead wire 10 during manufacturing can be easily controlled to be substantially constant, and micro pumps having uniform pump characteristics can be mass-produced. Further, according to the present invention, circular concave portions are formed at respective locations of the upper case 91 and the lower case 92 corresponding to the soldering portion 11 (lead wire connecting portion) of the lead wire 10 to the piezo vibrator 1. When the grooves 151 and 152 are provided and the two cases are combined, the concave grooves 151 and 152 are formed.
By facing, the soldered portion 1 of the lead wire 10
1 accommodates that part so as not to contact the inner wall of the case
A space is formed. Thus, the diaphragm 3 and the upper case 9
1 and the distance D2 between the diaphragm 3 and the inner wall of the lower case 92 can be reduced, and miniaturization can be effectively achieved. In particular, by reducing the distance D2 between the diaphragm 3 and the inner wall of the lower case 92, the volume of the pump chamber 8 can be reduced, and the cavity pressure increases by that much, thus making the pump discharge pressure effective. Can be increased. The volume of the pump chamber 8 is an important factor for determining the discharge pressure of the pump. The discharge pressure increases as the ratio of the vibration volume due to the amplitude of the piezoelectric vibrator 1 to the volume of the pump chamber 8 approaches 1. The pump characteristics of the discharge flow rate with respect to the load are improved. According to the present invention, the distance D2 between the diaphragm 3 and the inner wall of the lower case 92 is set to 0.6, which is about half the conventional value.
mm. As described above, in the micropump according to the present invention , the connecting portion of the lead wire to the piezo vibrator is
Upper case and lower case so that they do not
The concave groove provided at each corresponding location
Downsizing while securing the space for storing the wire connection part
Especially in the pump room.
Reduce the distance between the diaphragm and the inner wall of the lower case to
Pump discharge pressure can be effectively increased.
Have . Further, in the micro-pump according to the invention, Daiyafura a lead wire connected to the piezoelectric vibrator
Lead to the outside in parallel with the
The wire can be easily and securely connected to the piezo oscillator.
The connection is strong against pulling the lead wire.
It becomes And the tension of the lead wire
Acts in a direction different from the ram's vibration direction.
Almost no hindrance to movement, sufficient pumping properties
Ability can be demonstrated. And the structure
As a result, the state where the tension from the lead wire is most stable is obtained,
Almost constant tension when pulling out lead wires during manufacturing
Can be easily managed so that the pump characteristics
It has the advantage of mass-producing a complete micropump
Have .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view showing a micropump according to one embodiment of the present invention. FIG. 2 is a plan view showing an upper case of the micropump according to the embodiment. FIG. 3 is a front view of the upper case. FIG. 4 is a plan view showing a lower case of the micro pump in the embodiment. FIG. 5 is a sectional view of the lower case taken along line AA. FIG. 6 is a side sectional view showing a conventional micropump. FIG. 7 is a plan view showing a conventional micropump. FIG. 8 is a perspective view showing a sensor body of a miniaturized semiconductor type gas rate sensor. FIG. 9 is a simplified configuration diagram of a gas rate sensor when a micropump is combined with its sensor main body. [Description of Signs] 1 Piezoelectric vibrator 2 Ceramic plate 3 Diaphragm 4 Orifice 6 Inlet 7 Outlet 8 Pump chamber 91 Upper case 92 Lower case 10 Lead wire 11 Solder part (lead wire connection part) 151 Recessed groove 152 Concave groove

Continuation of the front page (56) References JP-A-4-101082 (JP, A) JP-A-5-296150 (JP, A) JP-A-1-272166 (JP, A) JP-A-62-147881 (JP) , A) Japanese Utility Model Sho 62-72481 (JP, U) Japanese Utility Model 1-28313 (JP, Y2) Japanese Utility Model 4-45245 (JP, Y2) (58) Fields surveyed (Int. Cl. ⁷ , DB) Name) F04B 9/00-15/08 F04B 43/00-47/14 F04B 53/00-53/22

Claims (1)

(1) A piezoelectric vibrator (1) is attached, a pump operation is performed by bending vibration of a diaphragm (3) having an orifice (4), and a pump operation is performed on the front surface of the diaphragm. In a micro pump in which a suction port (6) and a discharge port (7) are provided in the chamber (5), and the back of the diaphragm is a pump chamber (8), an upper case (91) and a lower case (92) are combined. To form a pump case, by providing concave grooves (151, 152) at respective locations of the upper case and the lower case corresponding to the lead wire connection portion of the piezo vibrator, and combining the two cases. in result bets as space for accommodating the lead wire connection portion is formed by a groove of the concave faces when the
First, the lead wire (10) connected to the piezoelectric vibrator is
A micropump characterized in that it is drawn out in parallel with the diaphragm .