JP2000350964A - Langevin type oscillator fastened by bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost bolt-fastened Langevin type oscillator with excellent vibration efficiency. SOLUTION: An even number of piezoelectric ceramics 2 respectively having electrode faces bearing electrodes formed thereon are so set as to set the faces with the same polarity to be faced and an even number of the piezoelectric ceramics 2 are overlaid while sandwiching electrodes 4 between neighboring piezoelectric ceramics. The resultant body of the piezoelectric ceramics 2 in the even number is sandwiched between a pair of metal blocks 5, 6 and the metal blocks 5, 6 are fastened by bolts 8 to obtain a Langevin type oscillator 1 fastened with bolts. As the electrodes, carbon electrodes 3 are formed on the electrode faces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolted vibrator used as a source of ultrasonic waves used in a washing machine or the like utilizing ultrasonic vibration or as a processing machine for welding plastics or the like.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, a structure of a bolted vibrator of this type is composed of a piezoelectric ceramic 9, an electric terminal (electrode plate) 4, a front plate (metal block) 5, and a backing plate (metal block). ) 6, insulating material 7, bolts 8 and other components.

Here, electrodes (not shown) are formed on both end surfaces (electrode surfaces) in the thickness direction of the piezoelectric ceramics 9. Conventionally, this electrode is formed by depositing silver or the like on the electrode surface of the piezoelectric ceramics 9 using a high-vacuum deposition apparatus.

[0004]

Electric power is supplied to the piezoelectric ceramics by electric terminals in contact with the electrodes, and a front plate and a backing plate. These contact surfaces simultaneously oscillate the vibration of the piezoelectric ceramics. Since the boundary is a boundary surface that is transmitted to the entire system, if there is a layer having a different acoustic impedance such as a foreign substance or an air layer on these boundary surfaces, problems such as a large vibration transmission loss and a large variation in vibration amplitude or efficiency will occur. was there.

In the above-described method for forming an electrode,
Since the electrodes are formed in a high vacuum space, there is a problem in terms of manufacturing cost.

It is therefore an object of the present invention to provide a bolted Langevin type vibrator which is excellent in vibration efficiency and low in cost.

[0007]

According to the present invention, an even number of piezoelectric ceramics each having an electrode formed on an electrode surface face the same polarity surfaces, and an electrode plate is sandwiched between the piezoelectric ceramics to sandwich the even number of piezoelectric ceramics. In a bolted Langevin type vibrator in which ceramics are overlapped, an even number of the overlapped piezoelectric ceramics are sandwiched between a pair of metal blocks, and the metal blocks are fastened with bolts, a carbon electrode is provided on the electrode surface as the electrode. A bolted Langevin type vibrator characterized by being formed is obtained.

[0008]

By forming a carbon electrode as an electrode formed on the electrode surface of the piezoelectric ceramic used in the bolted Langevin type vibrator of the present invention by, for example, printing (mesh printing, transfer printing, etc.), the electrode and the electrode are formed. The adhesion between the plate and the bonding surface between the electrode and the piezoelectric ceramics is improved, resulting in less variation in vibration amplitude and efficiency, and the formation of electrodes in the atmosphere at room temperature and pressure without using a high vacuum space. Because it is possible, it is excellent in cost performance.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of a bolted Langevin type vibrator according to an embodiment of the present invention.

This bolted Langevin type vibrator 1
Is composed of two piezoelectric ceramics 2, two electrode plates 4, a front plate (metal block) 5, a backing plate 6, an insulating material 7, and bolts 8.

Each of the piezoelectric ceramics 2 is substantially ring-shaped, and has an insertion hole 21 at the center thereof. Both end faces in the thickness direction of each piezoelectric ceramic 2 are electrode faces.

A carbon electrode 3 is formed on the electrode surface of each piezoelectric ceramic 2. The carbon electrode 3 is formed on the electrode surface of each piezoelectric ceramic 2 by printing (mesh printing, transfer printing, etc.).

Each electrode plate 4 has an insertion hole 41.
One of the two electrode plates 4 is sandwiched between the two piezoelectric ceramics 2, and the other electrode plate 4 is sandwiched between the piezoelectric ceramic 2 and the backing plate 6. When sandwiching the electrode plate 4 between the two piezoelectric ceramics 2, the two piezoelectric ceramics 2 face each other with the same polar face,
The electrode plate 4 is sandwiched therebetween.

The front plate 5 has a substantially columnar shape, and a central portion thereof has a concave portion 51 for receiving one end of the insulating material 7.
A female screw 52 is formed adjacent to the recess 51 and screwed to one end of the bolt 8.

The backing plate 6 is also substantially columnar, and has a central portion provided with a recess 61 for receiving the other end of the insulating material 7.
A female screw 62 is formed adjacent to the recess 61 and screwed to the other end of the bolt 8.

The insulating material 7 has a cylindrical shape, and the piezoelectric ceramics 2 stacked alternately and the insertion holes 21, 4 of the electrode plate 4.
1 is inserted. The alternately stacked piezoelectric ceramics 2 and electrode plates 4 are combined with a front plate 5 and a backing plate 6.
One end of the insulating material 7 fits into the recess 51 of the front plate 5 and the other end of the insulating material 7 fits into the recess 6 of the backing plate 6.
Fit into 1.

The bolt 8 is connected to the piezoelectric ceramic 2 and the electrode plate 4.
Are inserted into the insulating material 7 inserted through the insertion holes 21 and 41. Then, one end of the bolt 8 inserted into the insulating material 7 is screwed into the female screw 52 of the front plate 5, and the other end is screwed into the female screw 62 of the backing plate 6, so that the bolts 8 are stacked in a mating manner. The piezoelectric ceramics 2 and the electrode plate 4 are sandwiched between a front plate 5 and a backing plate 6.

As is apparent from the above description, the configuration of the conventional bolted Langevin type vibrator 1 shown in FIG. On the surface, a carbon electrode 3 is formed with a carbon paste. Conventionally, as described above, the electrodes have been formed by depositing a metal such as silver on the electrode surface using a high-vacuum deposition apparatus.

In the present embodiment, the carbon electrode 3 is screen-printed on the upper and lower surfaces (electrode surfaces) of the piezoelectric ceramics 2 at a temperature of 120 ° C. in a process before assembling the bolted vibrator 1. It is formed by drying for 60 minutes.

The carbon electrode 3 has a thickness of about 2 to 5 microns. Since the electrode formed by the conventional vapor deposition has a thickness of 0.1 μm or less, this electrode has almost no effect on the bonding surface with the backing plate 6 and the electrode plate 4. The contact area was influenced by the surface accuracy of each of the plate 6 and the electrode plate 4. By forming the carbon electrode 3, the material becomes a material filling the space between the joint surfaces, the contact area increases, and the reflection of vibration decreases. As a result, the efficiency of the vibration system using the bolted vibrator is improved, and variations in the piezoelectric characteristics (resonance frequency, amplitude, etc.) are reduced.

[0021]

As described above, according to the present invention, by making the electrode portion of the piezoelectric ceramics a carbon electrode made of carbon paste, the vibration efficiency can be improved and the cost of manufacturing the piezoelectric ceramics can be reduced. Since it can be reduced, it is possible to provide a bolted Langevin type vibrator having high quality.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a bolted Langevin type vibrator according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an example of a conventional bolted Langevin type vibrator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bolt-fastened Langevin type vibrator 2 Piezoelectric ceramics 3 Carbon electrode 4 Electrode plate 5 Front plate (metal block) 6 Backing plate (metal block) 7 Insulation material 8 Bolt 9 Piezoelectric ceramic

Claims (1)

[Claims] 1. An even number of piezoelectric ceramics, each having an electrode formed on an electrode surface, facing the same polarity surface,
During this, the even-numbered piezoelectric ceramics are overlapped by sandwiching the electrode plate, the even-numbered piezoelectric ceramics overlapped are sandwiched by a pair of metal blocks, and the metal blocks are fastened by bolts. , Wherein a carbon electrode is formed on the electrode surface as the electrode.