JP2990634B2 - Polarizing device for piezoelectric element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization device for a piezoelectric element, and more particularly to a polarization device for performing a polarization process on a piezoelectric element in a polarized liquid.

[0002]

2. Description of the Related Art Conventionally, a polarization treatment of a piezoelectric ceramic element is performed by applying a high voltage in an insulating polarization liquid such as silicon oil. However, this type of polarized liquid has a high viscosity and is poor in drainage. For this reason, the piezoelectric element after polarization must be cleaned, and a cleaning step is required separately from the polarization step. In addition, a solvent such as trichloroethane is used for washing,
Since this type of solvent is an ozone depleting substance, its use tends to be restricted.

[0003]

On the other hand, when a fluorine-based inert liquid is used as the polarizing liquid, the inert liquid has not only excellent insulating properties but also very low viscosity, so that the liquid runs out well and the cleaning is performed. There is an effect that a process is not required. Moreover,
The fluorine-based inert liquid is a substance that is harmless to the environment and the human body, and is therefore convenient for use. However, a fluorine-based inert liquid is very expensive, and for example, in the case of a commercially available fluorine-based inert liquid, Fluorinert (trade name), the cost is about 8,000 yen / kg. Therefore, it is important to reduce the consumption of the inert liquid as much as possible in order to reduce the polarization cost.

Accordingly, an object of the present invention is to provide a polarization device for a piezoelectric element which can reduce the consumption of a fluorine-based inert solution used as a polarization solution. Another object of the present invention is to provide a polarization device for a piezoelectric element which can improve work efficiency and easily control temperature.

[0005]

In order to achieve the above object, a polarization apparatus according to the present invention is provided with an intake chamber into which a piezoelectric element before polarization treatment is introduced, and is provided adjacent to the intake chamber, and is provided with a fluorine-based inert gas. A polarization bath for storing a polarization solution composed of a liquid, and performing a polarization process on the piezoelectric element in the polarization solution; a drying chamber provided adjacent to the polarization bath, for drying the piezoelectric element after the polarization process; and a drying chamber. An extraction chamber provided adjacent to the extraction chamber for taking out the dried piezoelectric element to the outside, and a recovery unit connected to the intake chamber and the extraction chamber for condensing and recovering the vapor of the polarized liquid in the chamber are provided. Things.

[0006]

The piezoelectric element before the polarization treatment is introduced into the polarization tank through the intake chamber. In the polarization tank, the piezoelectric element is immersed in a polarization liquid, and a high voltage is applied to perform polarization processing. After the polarization treatment, the polarizer is pulled up from the polarizer. However, since the polarizer is a fluorine-based inert liquid, the liquid is well drained and most of the inert liquid attached to the piezoelectric element flows down. Next, the polarized piezoelectric element enters the drying chamber, and the polarized liquid adhering to the piezoelectric element evaporates by means such as heating or blowing, and the polarized liquid is completely removed from the piezoelectric element. The piezoelectric element from which the polarized liquid has been removed is taken out of the drying chamber via the take-out chamber. When the piezoelectric element is introduced from the intake chamber into the polarization chamber, and when the piezoelectric element is taken out from the drying chamber to the extraction chamber, the inert liquid vapor in the polarization tank or the drying chamber flows out to the intake chamber or the extraction chamber. If this vapor is directly discharged into the atmosphere, the consumption of the inert liquid increases. Therefore, in the present invention, the recovery means is connected to the intake chamber and the extraction chamber to recover the vapor, thereby reducing the consumption of the inert liquid to the minimum.

When a drying means for heating and drying the piezoelectric element is provided in the drying chamber, the inert liquid vapor evaporated in the drying chamber is saturated, and the drying efficiency is deteriorated. Therefore, it is desirable that the evaporated inert liquid is condensed and collected by the collecting means, and the collected inert liquid is returned to the polarizing tank by the returning means. Thereby, the drying step can be performed efficiently, and the consumption of the inert liquid can be further reduced.

[0008]

FIG. 1 shows an example of a polarization device according to the present invention. The polarization device of this embodiment has an intake chamber 1 in order from the front,
It comprises four chambers, a polarization tank 2, a drying chamber 3, and an extraction chamber 4. Openable and closable doors 5 to 7 are provided between the respective rooms, and openable and closable doors 8 and 9 are also provided at the inlet of the intake chamber 1 and the outlet of the extraction chamber 4. Of the above doors, doors 5, 8 and 7, 9 provided on both sides of the intake chamber 1 and the extraction chamber 4 are highly airtight doors.

[0009] A circulation pipe 10 is connected to the intake chamber 1, and a blower 11 and a recovery unit 12 are provided in the pipe 10. As the recovery unit 12, for example, a cooling coil or the like can be used. The air in the intake chamber 1 flows to the collector 12 by the blower 11, where vapor in the air is condensed, and the dried air is returned to the intake chamber 1 through the pipe 10. The liquid (inert liquid) condensed in the recovery unit 12 is appropriately returned to the polarization tank 2.

A polarizing liquid 13 made of a fluorine-based inert liquid is stored in the lower part of the polarizing tank 2, and the polarizing liquid 13 is set at a predetermined temperature by a heater 14. Also,
A pair of electrodes 15 and 15 are arranged in the polarization liquid 13. The electrodes 15 and 15 sandwich the front and back surfaces of the piezoelectric element A, and perform a polarization process by applying a high voltage. A cooling coil 16 is arranged on the upper part of the polarization tank 2,
Has the function of condensing the vapor from the tank and returning it to the lower storage tank.

The drying chamber 3 is provided adjacent to the polarization tank 2,
The piezoelectric element A after the polarization treatment introduced through the communication port 17 with the polarization tank 2 is dried. In the upper part of the drying chamber 3, a blower 18 as a drying means and a heater 19 are arranged.
Further, the bottom of the drying chamber 3 is formed in a funnel shape, and after the steam in the drying chamber 3 is condensed by the cooling coil 20 for recovery,
The polarized liquid is stored at the bottom. A return pipe 21 is connected between the bottom of the drying chamber 3 and the bottom of the polarization tank 2, and a hydraulic pump 22 for returning the polarized liquid in the drying chamber 3 to the polarization tank 2 in the middle of the pipe 21. Is provided. The hydraulic pump 22 is driven when the amount of polarized liquid accumulated at the bottom of the drying chamber 3 exceeds a predetermined amount, and prevents the liquid level in the polarization tank 2 from dropping below a certain amount.

The take-out chamber 4 is provided adjacent to the drying chamber 3,
The dried piezoelectric element A is introduced through the communication port 23.
The take-out room 4 is a small room like the take-in room 1 and has a circulation pipe 24 connected thereto. In the middle of this pipe 24, blower 2
5 and a recovery unit 26 including a cooling coil and the like. The air in the extraction chamber 4 is collected by a blower 25 into a collecting device 26.
Where the vapor in the air is condensed, and the dried air is returned to the extraction chamber 4 through the pipe 24. Collection device 2
The liquid (inert liquid) condensed in 6 is appropriately returned to the polarization tank 2. The operations of the doors 5 to 9, the blowers 11 and 25, the hydraulic pump 22, the temperature of the polarizing liquid 13, and the temperature of the drying chamber 3 are integrally controlled by a controller (not shown).

Next, the operation of the polarization device having the above configuration will be described. First, the first door 8 is opened to take the piezoelectric element A before the polarization process into the entrance chamber 1, and then the door 8 is closed. Next, the second door 5 is opened, and the piezoelectric element A is introduced into the polarization tank 2. After the introduction,
Although the second door 5 is closed, the polarization liquid vapor in the polarization tank 2 enters the intake chamber 1 while the second door 5 is open.
1 is driven and this vapor is collected by the collecting device 12. In the polarization tank 2, the piezoelectric element A is immersed in the polarization liquid 13, and the electrodes 15,
In 15, the front and back surfaces of the piezoelectric element A are sandwiched, and a high voltage is applied to perform polarization processing. At this time, since the polarization liquid 13 is a fluorine-based inert liquid having a high insulating property, the polarization treatment can be performed safely similarly to the conventional silicon oil. When the piezoelectric element A is pulled up after the polarization, the polarization liquid 13 has a low viscosity, so that the liquid runs out well, and the polarization liquid 13 only adheres to the surface of the piezoelectric element A in a thin film form. Next, the third door 6 of the communication port 17 is opened, and after introducing the piezoelectric element A after the polarization process into the drying chamber 3,
The third door 6 is closed. The polarized liquid adhered to the piezoelectric element A in the drying chamber 3 evaporates instantly by the warm air blown by the blower 18. The evaporated polarized liquid is cooled and condensed by the cooling coil 20, and is stored at the bottom. The stored polarized liquid is returned to the polarization tank 2 by driving the hydraulic pump 22. Next, the fourth door 7 is opened, the piezoelectric element A after the drying process is introduced into the extraction chamber 4, and the fourth door 7 is closed. When the piezoelectric element A is introduced into the extraction chamber 4,
Part of the residual steam in the drying chamber 3 also enters the extraction chamber 4. Therefore, the vacuum pump 25 is driven with the doors 7, 9 closed,
The polarized liquid vapor in the extraction chamber 4 is recovered by the recovery device 26.
After the collection, the fifth door 9 is opened, and the piezoelectric element A is taken out.

In the above description, the case where one piezoelectric element A is subjected to polarization processing has been described.
May be set in a holder, and a series of processes may be performed while moving the holder in each room. In this case, the holders on which the piezoelectric elements A are set are intermittently introduced into the intake chamber 1 at regular intervals, and various processes such as polarization and drying are performed on the piezoelectric elements A set on the holders in parallel. You may do so.

In general, the degree of polarization of the piezoelectric element A changes according to the applied voltage, the applied time, and the temperature of the polarized liquid 13.
In the polarization tank 2, the temperature of the polarization liquid 13 is controlled by the heater 14. On the other hand, in the drying furnace 3, the temperature is controlled by the heater 19 in order to evaporate the polarized liquid. Therefore, it is necessary to control the temperature in the polarization tank 2 and the temperature in the drying furnace 3 separately. In the above embodiment, the polarization tank 2 and the drying chamber 3 are separated by the door 6, so that the temperatures of both chambers can be controlled independently, highly accurate polarization processing can be performed, and drying can be performed in a short time. . Furthermore, since the polarization tank 2 and the drying chamber 3 are separate rooms, the polarization processing and the drying processing can be performed in parallel, and the working efficiency is improved.

In the above-described embodiment, the blower 18 and the heater 19 are provided as drying means, and the piezoelectric element A is dried by blowing warm air thereon. Is very large, so that the inert liquid on the surface of the piezoelectric element A can be easily dried and removed simply by blowing cold air or applying mechanical force such as vibration, swing, rotation, or the like. . In the above embodiment, a door that can be opened and closed is provided between the polarization chamber and the drying chamber. However, a simple partition may be provided instead of the door. However, if the temperature of the polarization chamber and the temperature of the drying chamber are to be controlled separately, it is preferable to provide a door to separate the temperature. further,
In the above embodiment, the polarization tank and the drying chamber are arranged in parallel in the horizontal direction, but the drying chamber may be arranged above the polarization tank.
In this case, the polarization-treated piezoelectric element is raised and introduced into the drying chamber, and a door that opens and closes in the horizontal direction may be provided between the polarization tank and the drying chamber. In this case, the polarized liquid recovered in the drying chamber can be returned to the polarization tank under natural flow.

[0017]

As is apparent from the above description, according to the present invention, the polarization treatment is performed in a fluorine-based inert liquid having good drainage. It can be removed from the element, eliminating the need for a cleaning step and reducing the consumption of the inert liquid. In addition, an inlet chamber and an outlet chamber are provided before the polarization tank and after the drying chamber, respectively, and the inert liquid vapor in these chambers is collected by the collecting means, so that the inert liquid vapor leaking into the atmosphere is markedly reduced. Can be reduced, and the consumption of the inert liquid can be further reduced. Furthermore, since the polarization tank and the drying chamber are separated, the polarization processing and the drying processing can be performed simultaneously and in parallel, thereby improving the working efficiency and facilitating the temperature control in each chamber. .

[Brief description of the drawings]

FIG. 1 is a system diagram of an example of a polarization device according to the present invention.

[Explanation of symbols]

 A Piezoelectric element 1 Intake chamber 2 Polarization tank 3 Drying chamber 4 Extraction chamber 5-9 Door 12 Collector 13 Polarizer (fluorinated inert liquid) 18 Blower 19 Heater 20 Cooling coil 22 Hydraulic pump 26 Collector

Claims (2)

(57) [Claims] 1. An intake chamber into which a piezoelectric element before polarization treatment is introduced, and a polarized liquid made of a fluorine-based inert liquid, which is provided adjacent to the intake chamber and stored therein. A polarization tank for performing the treatment, a drying chamber provided adjacent to the polarization tank for drying the piezoelectric element after the polarization treatment, and a takeout provided adjacent to the drying chamber for taking out the dried piezoelectric element to the outside A polarization device for a piezoelectric element , comprising: a chamber ; and a recovery unit connected to the intake chamber and the extraction chamber, for condensing and recovering the vapor of the polarized liquid in the chamber. 2. The polarization device for a piezoelectric element according to claim 1, wherein the drying chamber includes a drying unit for heating and drying the piezoelectric element to which the polarization liquid has adhered, and a vapor of the polarization liquid in the drying chamber being condensed. A polarizing device for a piezoelectric element, comprising: a collecting means for collecting and a returning means for returning the collected polarized liquid to a polarizing tank.