JP3209935B2 - Piezoelectric element characteristic test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element characteristic test apparatus for easily measuring the characteristics of a piezoelectric element.

[0002]

2. Description of the Related Art Conventionally, in order to measure the electromechanical characteristics of a piezoelectric element such as zircon / lead titanate, a specially shaped test piece is prepared, polarized, and an electric signal is supplied between electrodes.
The electrical and mechanical properties were measured by the response to the electrical signal. That is, a two-terminal network having a mechanical terminal and an electric terminal supplies an electric signal from the electric terminal side,
Data of electrical and mechanical characteristics has been obtained from various electrical responses, for example, impedance response, height of resonance point, resonance frequency, and the like.

[0003]

However, such a test method can only obtain data as viewed from the electrical terminal side of a two-port network, so that the d constant and the like of a piezoelectric element having a complicated shape can be accurately determined. It was difficult to get. Further, since it is necessary to produce a test piece having a special shape, it is not possible to easily obtain the characteristics of the piezoelectric element itself flowing in an actual production line.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a piezoelectric element characteristic test capable of easily and accurately measuring the characteristics of a piezoelectric element. It is intended to provide a device.

[0005]

According to a first aspect of the present invention, there is provided a piezoelectric element characteristic test apparatus, wherein a piezoelectric element to be measured is applied by applying a magnetic attraction force between a base member and a holding member. It comprises a piezoelectric element holding section for holding, a vibrator for exciting the piezoelectric element holding section, and an indicator for indicating an output voltage or an output charge of the piezoelectric element.

According to a second aspect of the present invention, one of the base member and the holding member is an electromagnet, and the other is a magnetic member so that a magnetic attraction force acts between the base member and the holding member. A piezoelectric element holding section for holding the piezoelectric element to be measured by the vibration sensor, a vibrator for exciting the piezoelectric element holding section, and an indicator for indicating an output voltage or an output charge of the piezoelectric element. .

According to a third aspect of the present invention, there is provided a piezoelectric element characteristic testing apparatus in which one of a base member and a holding member is an electromagnet, and the other is a magnetic member to act a magnetic attraction between the base member and the holding member. A piezoelectric element holding unit for holding a piezoelectric element to be measured by the measuring means, and an indicator for indicating an output voltage or an output charge of the piezoelectric element, and the electromagnet is driven by a current in which DC and AC are superimposed. .

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a sectional view of the piezoelectric element characteristic test apparatus according to claim 1, FIG. 2 is an explanatory view of an annular shear type piezoelectric element to be measured, and FIG. 3 is claim 2 or 3.
FIG. 4 is a cross-sectional view of a piezoelectric element characteristic test apparatus according to the first embodiment.
It is sectional drawing of another embodiment of the piezoelectric element characteristic test apparatus which concerns on FIG.

The piezoelectric element characteristic test apparatus according to the first aspect is shown in FIG.
As shown in (1), it comprises a piezoelectric element holding unit 1, a voltmeter 2, and a vibrator (not shown). Note that the arrow A indicates the direction of vibration by the vibrator. The piezoelectric element holding portion 1 includes a base member 3 and
The holding member 4 includes a base member 3 and a holding member 4.
Each is connected to the input terminal of the voltmeter 2.

The base member 3 is made of, for example, a soft magnetic material such as a magnetic SUS alloy, and has a column 6 for supporting a piezoelectric element 5 to be measured on its upper end surface and a base member 3 on its lower end surface. A male screw 3a for attaching to a shaker is formed. Further, a tapered step 6 a is formed in the middle of the support 6.

The holding member 4 is formed in a thick cylindrical shape by a magnet such as a metal magnet, for example, and has a tapered step 4a formed on the upper inner peripheral surface thereof.

As shown in FIG. 2, the piezoelectric element 5 to be measured has a thick cylindrical shape, is polarized in the axial direction B, and has electrodes provided on the inner peripheral surface 5a and the outer peripheral surface 5b. An annular shear type piezoelectric element. Note that the inner diameter of the piezoelectric element 5 is slightly larger than the diameter of the column 6, and the outer diameter is slightly smaller than the inner diameter of the holding member 4.

Accordingly, when the piezoelectric element 5 is fitted to the column 6, the lower surface inner peripheral edge 5c contacts the step 6a, and the holding member 4 is further fitted to the piezoelectric element 5 fitted to the column 6. As a result, the outer peripheral edge 5d of the upper surface comes into contact with the step portion 4a and is held by the piezoelectric element holding portion 1.

In the embodiment of the present invention, the holding member 4 is a magnet, but the point is that a magnetic attraction force should be applied between the base member 3 and the holding member 4. It may be configured. For example, the base member 3
A part or the whole may be a magnet, and the holding member 4 may be a magnetic member. Further, a configuration in which a part of the holding member 4 is a magnet may be employed. Further, both the base member 3 and the holding member 4 may be magnets. However, in this case, they must be opposed with different polarities.

The operation of the apparatus for testing the characteristics of a piezoelectric element according to the present invention will be described. First, the base member 3 is screwed to the vibrator, the support 6 is inserted into the piezoelectric element 5,
Further, the holding member 4 is fitted to the piezoelectric element 5 into which the column 6 has been fitted. Then, the piezoelectric element 5 is reliably held between the base member 3 and the holding member 4 by the magnetic attraction acting in the direction of arrow C.

Next, the piezoelectric element 5 and the piezoelectric element holding section 1 are vibrated at a predetermined level in the direction of arrow A by the vibrator. A force, which is the product of the acceleration of the vibration and the mass of the holding member 4, is applied to the piezoelectric element 5. Then, a voltage corresponding to this force is generated between the two electrodes 5a and 5b of the piezoelectric element 5.
Therefore, if this voltage is measured by the voltmeter 2, the force-voltage characteristics of the piezoelectric element 5 can be obtained.

Further, if the holding member 4 is detached against the magnetic attraction acting between the base member 3 and the holding member 4, the holding state of the piezoelectric element 5 is released. They can be exchanged and characteristic tests can be performed one after another.

FIG. 3 shows a piezoelectric element characteristic test apparatus according to the present invention.
As shown in FIG. 5, a piezoelectric element holding unit 11, a voltmeter 12,
It consists of a vibrator (not shown). Note that the arrow D indicates the direction of vibration by the vibrator. The piezoelectric element holding section 11 includes a base member 13 and a holding member 14, and the base member 13 and the holding member 14 are connected to input terminals of the voltmeter 12, respectively.

The base member 13 is formed of, for example, a soft magnetic material such as a magnetic SUS alloy, and has a column 16 for supporting the piezoelectric element 5 to be measured on its upper end surface and a base member 13 on its lower end surface. Male screw 1 for mounting on a shaker
3a is formed. Further, a tapered step 16 a is formed in the middle of the support 16.

Further, on the outer periphery of the base member 13, the coil 1
7 is wound, and a current source 18 for supplying an exciting current to the coil 17 is connected. Therefore, by supplying an exciting current to the coil 17, the base member 13 functions as an electromagnet. Reference numeral 19 denotes a power on / off switch.

The holding member 14 is formed of a magnetic material such as a magnetic SUS alloy into a thick cylindrical shape, and has a tapered step 14a formed on the upper portion of the inner peripheral surface thereof. Note that the holding member 14 may be an electromagnet, and the base member 13 may be formed of a magnetic material.

The inner diameter of the piezoelectric element 5 is slightly larger than the diameter of the column 16, and the outer diameter is slightly smaller than the inner diameter of the holding member 14. Accordingly, the lower surface inner peripheral edge 5c of the piezoelectric element 5 is fitted to the column 16 by fitting the step 16a, and the holding member 14 is fitted to the piezoelectric element 5 fitted to the column 16 by fitting. The outer peripheral edge 5d of the upper surface abuts on the step portion 14a and is held by the piezoelectric element holding portion 11.

The operation of the piezoelectric element characteristic test apparatus according to the second aspect will be described. First, the base member 13 is screwed into the vibrator, the support 16 is inserted into the piezoelectric element 5, and the holding member 14 is further inserted into the piezoelectric element 5 into which the support 16 is inserted.
Is fitted. When the switch 19 is turned on, the coil 17 is excited by a direct current, an electromagnetic force, which is a static attraction, acts between the base member 13 and the holding member 14 in the direction of arrow E, and the piezoelectric element 5 It is securely held by the member 13 and the holding member 14.

Next, the piezoelectric element 5 and the piezoelectric element holding section 11 are vibrated at a predetermined level in the direction of arrow D by the vibrator. The piezoelectric element 5 includes the acceleration of vibration and the holding member 14.
A force is applied which is the product of the mass of Then, a voltage corresponding to this force is generated between the two electrodes 5a and 5b of the piezoelectric element 5. Then, if this voltage is measured by the voltmeter 12,
The force-voltage characteristics of the piezoelectric element 5 can be obtained.

Further, if the switch 19 is turned off,
Since the base member 13 does not function as an electromagnet, the holding state of the piezoelectric element 5 is released, and the piezoelectric element 5 can be easily replaced with the next piezoelectric element to be measured, and a characteristic test can be performed one after another.

FIG. 3 shows a piezoelectric device characteristic test apparatus according to the present invention.
A current source 18 supplies an exciting current in which alternating current is superimposed on direct current to a coil 17 shown in FIG.
In addition, the alternating force required as a vibrator according to the AC component is applied together with the static suction force required to hold the piezoelectric element 5 according to the DC component. Other configurations are the same as those of the piezoelectric element characteristic test apparatus of the second aspect.

The operation of the apparatus for testing the characteristics of a piezoelectric element according to the third aspect will be described. First, the support 16 is fitted into the piezoelectric element 5, and the holding member 14 is fitted into the piezoelectric element 5 into which the support 16 has been fitted. And switch 1
When the switch 9 is turned on, the coil 17 is excited by a direct current component, and an electromagnetic force, which is a static attractive force, acts between the base member 13 and the holding member 14 in the direction of arrow E. It is securely held by the holding member 14.

At the same time, the coil 17 is excited by an alternating current,
An alternating force generated in the direction of arrow D is applied to the piezoelectric element 5. Therefore, if the output voltage of the piezoelectric element 5 according to the alternating force generated in the direction of the arrow D is measured by the voltmeter 12, it is possible to realize a characteristic test apparatus that does not require a vibrator.

In the above-described embodiment, the case where the piezoelectric element 5 to be measured is the annular shear type piezoelectric element 5 has been described. However, the present invention is not limited to this. Also applicable to However, in this case, it is necessary to appropriately change the shape and function of the piezoelectric element.

FIG. 4 shows a piezoelectric element characteristic test apparatus for measuring a disk-shaped compression type piezoelectric element 25.
1, a voltmeter 22, and a vibrator (not shown). The piezoelectric element holding portion 21 includes a base member 23 and a holding member 24, and has a concave portion 23 a on an upper end surface of the base member 23 and a concave portion 24 a on a lower end surface of the holding member 24.

The piezoelectric element 25 is held between the base member 23 and the holding member 24 while being fitted in the recesses 23a and 24a. The recesses 23a and 24a can prevent the piezoelectric element 25 from deviating from a predetermined position due to vibration or the like.

In the above embodiment, the output voltage of the piezoelectric element 5.25 is measured by the voltmeters 2, 12, 22. However, the output charge may be measured. Further, in FIGS. 1 and 3, the columns 6, 16 are formed integrally with the base members 3, 13, but they may be formed separately. In this case, the columns 6, 16 are made of non-magnetic members. It may be formed.

[0033]

As described above, according to the first aspect of the present invention, the piezoelectric element is held between the base member and the holding member by magnetic attraction, so that the piezoelectric element can be formed with high precision and ease. Element characteristics can be measured.

According to the second aspect of the present invention, one of the base member and the holding member has an electromagnet function, the piezoelectric element to be measured is disposed between the base member and the holding member, and the electromagnet is driven to drive the electromagnet. Since the element is held, the attachment / detachment of the piezoelectric element to / from the piezoelectric element holding portion becomes easy.

According to the third aspect of the present invention, since the electromagnet is driven by a current in which DC and AC are superimposed, a vibrator is not required and the configuration is simplified.

[Brief description of the drawings]

FIG. 1 is a sectional view of a piezoelectric element characteristic test apparatus according to claim 1.

FIG. 2 is an explanatory view of an annular shear type piezoelectric element to be measured.

FIG. 3 is a sectional view of a piezoelectric element characteristic test apparatus according to claim 2 or 3;

FIG. 4 is a sectional view of another embodiment of the piezoelectric element characteristic test apparatus according to claim 1;

[Explanation of symbols]

1,11,21 ... piezoelectric element holding part, 2,12,22 ... voltmeter (indicator), 3,13,23 ... base member, 4,1
4, 24 ... holding member, 5, 25 ... piezoelectric element, 6, 16 ...
Prop, 17 ... Coil, 18 ... Current source, 19 ... Power on / off switch.

Claims (3)

(57) [Claims] A piezoelectric element holding portion for holding a piezoelectric element to be measured by applying a magnetic attraction force between a base member and a holding member; and a vibrator for exciting the piezoelectric element holding portion. An indicator for indicating an output voltage or an output charge of the piezoelectric element. 2. A piezoelectric element to be measured is held by applying a magnetic attraction force between the base member and the holding member using one of the base member and the holding member as an electromagnet and the other as a magnetic member. A piezoelectric element characteristic test apparatus, comprising: a piezoelectric element holding unit that vibrates the piezoelectric element holding unit; a vibrator that vibrates the piezoelectric element holding unit; and an indicator that indicates an output voltage or an output charge of the piezoelectric element. 3. A piezoelectric element to be measured is held by applying a magnetic attraction force between the base member and the holding member using one of the base member and the holding member as an electromagnet and the other as a magnetic member. A piezoelectric element holding section, and an indicator for indicating an output voltage or an output charge of the piezoelectric element, and the electromagnet is driven by a current in which DC and AC are superimposed.