JPS60160187A - Manufacture of vibrator - Google Patents

Abstract

PURPOSE:To maintain the constant amplitude without correction of an applied voltage to a vibrator by applying a d.c. voltage by which a piezoelectric ceramic thin plate shows an extending direction or a shortening direction to this plate when sticking the plate and a metallic thin film together. CONSTITUTION:The disc-shaped piezoelectric ceramic thin plate 2 is stuck to the disc-shaped metallic thin plate 5 under the condition that the voltage by which said piezoelectric thin plate 2 shows an extending direction is applied to this plate 2. Namely, the flat thin plates 2 and 5 both of which do not bend under the condition that a d.c. is applied with the thin plate 2 side as a negative pole are stuck together by use of an adhesive to fabricate an unimorph vibrator 1. After completing the sticking, the vibrator 1 bends as shown in the drawing when application of a voltage stops. Thus, an internal stress is applied to the plate 2 is inverse direction to the variation in a low-temperature region in advance. Consequently, the thin plate 5 shrinks more than the thin plate 2 according to the variation of temperature toward the low-temperature region and the internal stress is alleviated and the amplitude is enlarged. Then the reduction of discharge quantity due to enhancement of viscosity in the low-temperature region can be compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for manufacturing a vibrator made by bonding a piezoelectric ceramic thin plate and a metal thin plate together for directly converting electricity into vibration.

<Prior art> Conventionally, pumps for liquid fuel use electric motors or solenoids to operate impellers, pistons, or plungers, and their rotational or reciprocating motion applies centrifugal force to the liquid fuel and discharges it, or pumps the liquid into a cylinder. It had a structure that discharged water 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, and the impeller and piston receive the rotational movement of the electric motor through the transmission shaft. In addition, the plunger performs its function using the magnetic field (electromagnetic force) generated by the current flowing through the solenoid, but having such an intermediate transmission mechanism increases the size of the pump itself, and the internal structure. I was making it complicated.

In view of the above points, the applicant of the present application has simplified the structure and miniaturized the pump by using a unimorph vibrator that directly converts electrical energy into vibration, which is a reciprocating motion, in the pressurizing part of the pump. Patent application 1987-7538 has already been filed for the pump to be obtained.
I proposed this in issue 1.

First, this technology will be explained based on the drawings.

Figures 1, 2 and 3 are plan views of liquid fuel pumps, respectively;
4 and 5 are a sectional view and a bottom view, respectively, and FIGS. 4 and 5 are a bottom view and a side view, respectively, of a disc-shaped unimorph vibrator in which two metal thin plates are bonded to one piezoelectric ceramic thin plate used for the vibrating part. It is.

In Figures 1', 2, and 3, 1 is a disk-shaped unimorph vibrator using a piezoelectric ceramic thin plate (piezo element) 2 as a vibrating part, and a pump body consisting of three component pieces 3a, 3b, and 3c. A disk-shaped unimorph vibrator 1 is arranged in a liquid pressurizing chamber 4 inside the liquid pressurizing chamber 3 so that its volume can be expanded or contracted. Reference numeral 5 denotes a metal thin plate which constitutes the unimorph vibrator 1 together with the piezoelectric ceramic thin plate 2, 6 a discharge side check valve, 6a a discharge passage, 7 a suction side check valve, 7a a suction passage, and 6b a discharge side joint. ,? b is a suction side joint, 8 is an annular elastic body, 9 is a conducting wire, and 10 is an annular elastic body.

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 FIG. 5(b), the discharge side check valve 6 closes and the suction side check valve 6 closes. Check valve 7
opens and liquid fuel flows into the liquid pressurizing chamber 4.

Next, when the unimorph oscillator 1 changes from a planar shape to a convex shape as shown in FIG. The fuel is 1) pressure-fed 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 is deformed into an uneven shape alternately as shown in FIGS. 5(a) and (b), and the magnitude Δρ depends on the magnitude of the voltage. A proportional amount of deflection is obtained, and the discharge flow rate of the pump is controlled by voltage.

According to the above-mentioned prior art, the following effects are expected.

(b) By using a unimorph resonator, the function and structure are simplified and miniaturization becomes possible.

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

(c) The conventional intermediate transmission mechanism can be omitted, and loss in this 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, the ambient temperature of the pump is low (-10 to -20℃)
), the pump discharge flow rate decreases due to the difference in thermal contraction of the piezoelectric ceramic thin plate and the metal thin plate and the increase in the viscosity of the liquid to be pumped.

As a countermeasure, it is necessary to understand the relationship between the discharge flow rate and temperature and correct the voltage applied to the vibration circuit section of the unimorph vibrator 1.

The reason why the unimorph resonator 1 curves due to the difference in thermal contraction is as follows. Normally, the piezoelectric ceramic thin plate 2 and the metal thin plate 5 are bonded together at around room temperature (around 20°C), and as shown in FIG. The test is carried out in a state where no voltage is applied to the thin porcelain plate 2.

However, when the temperature becomes low, the thermal contraction of the piezoelectric ceramic thin plate 2 and the metal thin plate 5 is different, so that internal stress is applied to the piezoelectric ceramic thin plate 2 as shown in FIG. 5(b).
The amount of deflection (amplitude) becomes smaller. Further, the viscosity of the pressure-fed liquid is large (for example, kerosene has a kinematic viscosity of 1.6-3.5 cgL at a temperature of 20 to -10°C). For the above reasons, the pump discharge flow rate tends to decrease in the low temperature range (-10 to -20°C).

Purpose The present invention has been made in view of the above-mentioned problems, and is aimed at manufacturing a vibrator that can maintain an almost constant amplitude even when the ambient temperature is low or high without correcting the voltage applied to the vibrator. The purpose is to provide a method.

<Example> Hereinafter, an example of the present invention will be explained based on FIGS. 6(a) and (b). First, as shown in FIG.
A disc-shaped piezoelectric ceramic thin plate 2 having a thickness of 0.4 to 0.7 mm is bonded to a disc-shaped metal thin plate 5 while applying a voltage in the direction of elongation. That is, the piezoelectric ceramic thin plate 2 side is the negative electrode, and 6
A flat piezoelectric ceramic thin plate 2 that does not bend when a direct current of 0 to 45 V is applied and a metal thin plate 5 are bonded together using an adhesive such as epoxy resin in an atmosphere of about 30° C. for about 8 hours. The alignment is completed and the unimorph resonator 1 is manufactured.

After this bonding is completed, when the voltage application is stopped, the unimorph vibrator 1 curves by 7 to 8 μ as shown in FIG. 6(b). Note that the amplitude during vibration is about 10 to 15 μ.

As described above, in the present invention, internal stress is applied to the piezoelectric ceramic thin plate 2 in the direction opposite to the change in the low temperature range, and as the temperature changes to the low temperature range, the metal thin plate 2
shrinks more than the piezoelectric ceramic thin plate 2, and its internal stress is relaxed, creating an amplitude force (which compensates for the decrease in discharge flow rate due to increased viscosity in the low temperature range).

In addition, above, we have explained the manufacturing method of the Unimol 7 vibrator that can compensate for pressure-fed materials (liquids, gases, powders) in low-temperature ranges, but conversely, for pressure-fed materials that require correction in high-temperature ranges. Of course, the unimorph resonator may be manufactured in a state where a voltage is applied in the direction in which the piezoelectric ceramic thin plate contracts.

<Effects> As is clear from the above description, the present invention provides a method for manufacturing a vibrator in which a piezoelectric ceramic thin plate and a metal thin plate are bonded together, which directly converts electricity into vibration. The present invention relates to a method for manufacturing a vibrator, characterized in that a DC voltage is applied to the piezoelectric ceramic thin plate in an elongating direction or a shortening direction when bonding the piezoelectric ceramic thin plates together.

Therefore, according to the present invention, there is an excellent effect that it is possible to easily manufacture a vibrator whose amplitude can be maintained substantially constant even when the ambient temperature is low or high without correction of the voltage applied to the vibrator.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway plan view of the liquid feeding pump of the prior art;
The figure is a longitudinal sectional view of the same, Figure 3 is a partially cutaway plan view of the same, Figure 4 is a bottom view of the disc-shaped unimorph vibrator used in the vibrating part of the pump, and Figures 5 (a) and (b) are 6(a) and 6(b) are side views for explaining the method of manufacturing a unimorph resonator of the present invention. 1: Unimol 7 vibrator, 2: piezoelectric ceramic thin plate, 4: pressurizing chamber, 5: metal thin plate. Procedural amendment (Kamemu) 1939 ζ to May 3Q 1, Manufacturing method of display vibrator 3, Person making the amendment Relationship to the case Applicant name (L 8) < s O 4) Sharp Corporation 4, Agent Muku 541 Address Imperial Senba 5, 4-57 Minamihonmachi, Higashi-ku, Osaka City Date of amendment order (Showa date) Month, day (shipment date) 6, Number of inventions increased by amendment 7, Page 6 14 of the specification subject to amendment The description in line 16 is "Disc-shaped metal thin plate 5 with a voltage applied in the direction in which the disc-shaped piezoelectric ceramic thin plate 2 extends" is changed to "The disc-shaped piezoelectric ceramic thin plate 2 made of lead zirconate titanate porcelain is extended." The diameter is 33 mm and the thickness is 0.4 m when the voltage in the direction is applied.
Corrected as ``Stainless steel plate type thin metal plate 5''.

Claims (1)

[Claims] In a method for manufacturing a vibrator in which a piezoelectric ceramic thin plate and a metal thin plate are bonded together, which directly converts electricity into vibration, when the piezoelectric ceramic thin plate and the metal thin plate are bonded together, the piezoelectric ceramic thin plate has a direction in which the piezoelectric ceramic thin plate is stretched or shortened. A method for manufacturing a vibrator, characterized by applying a direct current voltage in a direction.