JPS59200082A - Liquid feed pump - Google Patents

Abstract

PURPOSE:To reduce the size of pump and to simplify the structure by employing an unimolf vibration chip for directly converting the electric energy to reciprocal motion or vibration in the pump mechanism thereby eliminating an intermediate transmission mechanism. CONSTITUTION:In a liquid feed pump employing an unimolf vibration chip 1 sticked of a thin metal plate 5 and a thin Piezo ceramic plate 2 for directly converting the electricity into vibration at the vibrating section for pressurizing the liquid, the thickness of said plate 2 is made to 0.4-0.7mm. and the outer diameter to 18-25mm. while the thickness of said plate 5 is made to 0.2-0.5mm. and the outer diameter to 25-30mm. for the delivery pressure of pump in the range of 0-0.20kg/cm<2>. Consequently even upon application of A.C. allowable voltage of 50Hz or 60Hz, required amount of warming fuel can be delivered continuously without causing aging to enable elimination of an intermediate transmission mechanism resulting in reduction of entire size of pump and simplification of internal structure.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a liquid pump that uses a unimorph vibrator made of a piezoelectric ceramic thin plate and a metal thin plate bonded together, which directly converts electricity into vibration, in a vibrating part that pressurizes a liquid.

<Prior art> Conventional liquid pumps use electric motors and solenoids to operate impellers, pistons, or plungers, and their rotational and reciprocating motions apply centrifugal force to liquid fuel and discharge it.
It had a structure in which it was discharged by expanding and contracting the internal volume. However, in this conventional pump, the impeller, piston, plunger, etc. that act directly on the liquid fuel cannot move by themselves even if an electric signal is applied. In addition, the plunger completes its operation using the magnetic field (electromagnetic force) caused by the current flowing through the plunger/id, but having such an intermediate transmission mechanism increases the size of the pump itself and also causes internal problems. The structure was complicated.

<Prior Application Technology> In view of the above points, the present inventor simplified the structure by using a unimorph vibrator that directly converts electrical energy into vibration, which is a reciprocating motion, in the mechanical part of the pump.
We have already proposed a new, smaller liquid pump.

First, an example of the fuel pump using a single disc-shaped unimorph resonator will be described with reference to the drawings.

Figures 1, 2, and 3 are a plan view, a sectional view, and a bottom view of the liquid pump, respectively, and Figures 4 and 5 are a piezoelectric ceramic thin plate and a metal thin plate used for the vibrating part, respectively. FIG. 2 is a bottom view and a cross-sectional view of a disc-shaped unimorph resonator made by bonding together the following.

In Figure 1.2.3, 1 is a piezoelectric ceramic thin plate (
It is a disk-shaped unimorph oscillator using a piezo element) 2, and it is used to expand or contract the volume of the liquid pressurizing part 4 inside the pump body 3 consisting of three component pieces 3a, 3b, and 3c. A disk-shaped unimorph resonator 1 is arranged.

Reference numeral 5 denotes a metal thin plate that constitutes the unimorph vibrator 1 together with the piezoelectric ceramic thin plate 2, 6 a discharge side check valve, 7 a suction side check valve, 8 a discharge side joint, 9 a conductive wire, and 10 a unimorph vibrator. The fixing ring 11 is a suction side joint.

In the liquid pump having the above structure, when positive and negative voltages of a constant frequency are applied to the conducting wire 9 connected to the unimorph vibrator 1, the unimorph vibrator 1 becomes uneven as shown in FIGS. 5(a) and 5(b). transforms alternately.

There are two check valves 6°7 in front of this unimorph vibrator 1, and when the unimorph vibrator 1 changes into a concave shape as shown in Figure 5 (I)), the discharge side check valve 6 closes. The suction side check valve 7 opens and the bookbinding fuel flows into the liquid pressurizing section 4.

Next, when the unimorph vibrator 1 changes from a planar shape to a convex shape as shown in FIG. 5(a), the suction side check valve 7 closes and the discharge side check valve 6 opens. The fuel is pumped through the discharge side check valve 6.

When a positive and negative voltage of a constant frequency is applied to the conductor @9, the unimorph resonator 1 deforms into an uneven shape alternately as shown in Fig. 5(a) and (+), but the magnitude Δρ is The amount of deflection is obtained in proportion to the magnitude of the voltage, and the discharge flow rate of the pump can be controlled by the voltage.
□1 As mentioned above, this liquid pump is characterized by using a disc-shaped Unimol 7 vibrator 1 that directly converts electricity into vibration in the vibrating part that pressurizes the liquid, and has the following characteristics. You can get the following effect.

(b) Functions and structures are simplified, allowing for miniaturization.

(b) (The number of geometric parts is reduced, the cumulative influence of shape accuracy of each part is reduced, and high quality can be expected.

(c) The conventional intermediate transmission mechanism can be omitted, and loss in the intermediate transmission mechanism can be eliminated, resulting in high efficiency.

(d) It is inexpensive in terms of cost.

(e) Since there is no reciprocating movement, there are no quality problems due to wear and tear.

(f) The discharge amount is controlled linearly depending on the voltage level.

However, when using a general household power supply, frequency 5
There are both 0Hz and 60Hz, and since the two conductive wires 9 connected to the unimorph vibrator 1 are AC, positive and negative voltages are applied alternately. Under such conditions, the durability of the unimorph resonator 1 becomes a problem.

Therefore, the present invention aims to develop a unimorph vibrator that can discharge the required amount of fuel for use as a general household heater without causing any change over time even when positive and negative allowable voltages are alternately applied to the unimorph vibrator. This paper proposes the shapes of the piezoelectric ceramic thin plate and the metal thin plate.

<Example> Hereinafter, embodiments of the present invention will be described with reference to FIG. 6 and subsequent figures.

As shown in FIGS. 6 and 7, in order to downsize the liquid pump, the unimorph vibrator 1 of the present invention has an outer diameter 5D of the metal thin plate 5 in the range of 25 to 30 mm, and a piezoelectric ceramic thin plate bonded thereto. The outer diameter 2D of No. 2 is set in the range of 18 to 25 mm. And this unimorph oscillator 1 is the second,
As shown in Figure 3, it is assembled into a liquid feed pump. Now, an example of the measurement result due to the pressure fluctuation of the liquid feed pump using this unimorph vibrator 1 will be explained with reference to FIG. 8. As can be seen from this figure, the discharge flow rate Q and the discharge pressure P increases, or there is a limit to the applied voltage. This applied voltage must be within a permissible voltage range in which the direction of polarization, which is polarized during the manufacturing process of the piezoelectric ceramic thin plate 2, does not disappear due to the applied alternating current reverse voltage. The allowable voltage increases in proportion to the thickness of the piezoelectric ceramic thin plate 2. The material of the piezoelectric ceramic thin plate 2 is a lead zirconate titanate based piezoelectric ceramic material having a relatively high piezoelectric constant.

Figures 9(a) and (b) are 60Hz, 90■ and 501, respectively.
(Characteristics of the liquid pump due to the difference in the thickness of the thin metal plate 5 at Z, 90 to 7. The maximum discharge flow rate and maximum discharge pressure vary depending on the thin metal plate 5, and as the thickness t of the metal thin plate 5 increases, the discharge flow rate at the same voltage decreases.

However, the rate of change in the discharge flow rate with respect to pressure fluctuations becomes small.

Therefore, it is possible to secure a certain allowable voltage \j, and the voltage range from 0 to 0
．． The thickness of the piezoelectric ceramic thin plate 2 and metal thin plate 5 of the unimorph vibrator 1 when a discharge pressure of 20 kg/cm2 is required is 4 000 Kc, which is the general household heating capacity.
In order to satisfy the required fuel consumption of less than al/hr, it is appropriate that the thickness of the thin metal plate 5 is 0.2 to 0.5 mm, and the thickness of the piezoelectric ceramic thin plate 2 is 0.4 to 0.7 mm. .

In addition, when the metal thin plate 5 becomes 0.6 mm or more, the discharge flow rate becomes insufficient, and the function as a household heating appliance is lost.

<Effects> As is clear from the above description, the present invention provides a liquid pump that uses a unimorph vibrator in which a piezoelectric ceramic thin plate and a metal thin plate are bonded together to directly convert electricity into vibration in a vibrating part that pressurizes a liquid. , the pump discharge pressure is 0 to 0.20 kg
/cm2, the shape and dimensions of the unimorph resonator are such that the thickness of the piezoelectric ceramic thin plate is 0.4 to 0.7 mm, the outer diameter thereof is 18 to 25 mm, and the thickness of the metal thin plate is 0.4 to 0.7 mm.
The diameter is 2 to 0°Smm, and the outer diameter is 25 to 30mm.
・] Therefore, in the present invention, the unimorph oscillator has a frequency of 50 Hz or 60 Hz.
Even when a permissible alternating current voltage of Hz is applied, there is an excellent effect in that the required consumption amount of fuel for use as a general household heating island can always be discharged satisfactorily without causing any change over time.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway plan view of the liquid feeding pump of the prior art;
Figure 3 is a partially cutaway bottom view of the same, Figure 4 is a bottom view of the disc-shaped unimorph vibrator used in the vibrating part of the pump, Figures 5 (a), (1)) is an explanatory diagram of its action,
FIG. 6 is a bottom view of the disc-shaped unimorph resonator 1 of the present invention;
Fig. 7 is a side view of the same side, Fig. 8 is a line diagram showing measurement results due to pressure fluctuations in an embodiment of the liquid feeding pump of the present invention, and Fig. 9 (
a) is a diagram showing the pressure fluctuation characteristics due to the difference in the thickness of the thin metal plate at an applied voltage of 60 Hz and 90 V;
1)) is a diagram showing the pressure fluctuation characteristics mainly due to the difference in the thickness of the thin metal plate at 50 Hz and 90 V. 1: Unimol 7 vibrator, 2: Piezoelectric ceramic thin plate, 3: Pump body, 4: Liquid pressurizing part, 5: Metal thin plate, 6: Discharge side check valve, 7: Suction side check valve, 8: Discharge Side joint, 9: Conductor. Applicant Sharp Corporation Figure 1 Figure 49 Figure 6 Figure 5 (a)

Claims (1)

[Claims] In a liquid pump that uses a unimorph oscillator (1) made by laminating a piezoelectric ceramic thin plate (2) and a metal thin plate (5) that directly convert electricity into vibrations in the vibrating part that pressurizes the liquid, the pump discharge pressure is In the range of 0 to 0.20 kg/cm2,
The shape and dimensions of the unimorph resonator (1) are such that the piezoelectric ceramic thin plate (2) has a thickness of 0.4 to 0.7 m, the outer diameter thereof is 18 to 25 mm, and the metal thin plate (5) has a thickness of 0.4 to 0.7 m. 0.
2-0. 5+nm, its outer diameter is 25~3011111
1. A liquid feeding pump characterized by: