JPH1042386A - Planner vibrator and echo sounder using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently transmit the extending movement in the radius direction of an active disk body to a disk to easily generate bending movement and the make a planer vibrator high in power by the same driving signal by providing plural grooves on a junction face with the active disk body in the disk. SOLUTION: The plural grooves having prescribed depth are malformed on the adhering face side of the active disk body 1 of the metallic disc 2 in the radium. The groove parts are not adhered to the active disk body 1. The circle face of the metallic disk 2, which is viewed from the active disk body 1, is separated into fan-type boards which are substantially approximated to a rectangle and which can easily be bent. The driving force of expansion and contraction in the direction of the radius effectively operate and the gas-type boards can efficiently be bent. Since the plural grooves are formed as compared to the metallic disk 2 without the groove, the rigidity of thematic disk 2 is deteriorated as a whole and the displacement of the bending vibration of the metallic disk 2 can be increassed for the same driving force by the active disk body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroacoustic transducer, and more particularly to a plate-shaped vibrator used for a sonar or the like and a transmitter using the plate-shaped vibrator.

[0002]

2. Description of the Related Art Detection of underwater objects and targets by sonar,
2. Description of the Related Art In the fields of exploration of marine resources, investigation of ocean currents, and the like, low-frequency ultrasonic waves are used because of their advantages such as low propagation loss in water and propagation to distant places.

[0003] As such a transmitter for ultrasonic radiation,
2. Description of the Related Art A piezoelectric ceramic oscillator type transmitter using a piezoelectric ceramic as an electromechanical energy conversion material is used. In particular, as a transmitter with high vibration generation efficiency and good low-frequency transmission characteristics, the displacement is expanded by a transmitter structure combining a metal disk and an active disc such as a piezoelectric ceramic. Has been proposed (Japanese Patent Application No. 4-22560).
No. 4-147026, Japanese Patent Application No. 4-1702
No. 8).

FIG. 5 shows a conventional plate-shaped vibrator and a wave transmitter combining the same. The plate-shaped vibrating body has a plate-shaped vibrating body configuration including a metal disk 2 made of an aluminum alloy or the like having a depression on a main surface, and an active disk 1 of a piezoelectric ceramic which is fitted into and bonded to the depression of the metal disk 2.

The driving principle of this plate-shaped vibrator is that the active disc 1 is displaced in the radial direction by applying a drive signal to the electrodes provided on both sides of the active disc 1, and the active disc 1 is displaced in the radial direction. The metal disk 2 to be bonded to the disc 1 is driven by the bonding surface of the recessed portion to bend the metal disk 2 to convert the vibration into bending vibration of the entire plate-shaped vibrator.

[0006] Further, as the wave transmitter, two plate-shaped vibrators are joined at a peripheral portion. As an actual transmitter, a junction at a peripheral portion is formed by FRP (Fiber Reinfo).
rced plastics) or a structure in which the periphery thereof is joined by a metal ring of a material having high hardness and the metal ring portion is fixed by a spring band or the like.

[0007]

The above-mentioned plate-shaped vibrating body is
It has a relatively simple and thin basic structure, and has the advantage that a thin and light-weight flexural vibrator can be realized without deteriorating water pressure resistance. By combining them, an efficient transmitter can be configured.

However, in the structure of the conventional plate-shaped vibrating body, since the entire joining surface between the active disc 1 and the metal disk 2 is firmly joined, the active disc 1 in the circumferential direction of the disc 1 is firmly joined. Spreading vibration is restrained at the joint surface of the metal disk 2, and radial expansion and contraction, which is effective for bending motion, is also suppressed. Loss occurs in converting the spreading motion of the active disc 1 into bending motion. There was a problem.

In the structure of the conventional plate-shaped vibrator, the vibration frequency depends on the hardness of the metal disk 2, and it is difficult to lower the frequency determined by the selected metal disk 2 to a lower frequency.

The present invention provides a plate-shaped vibrator capable of efficiently converting a spreading motion of an active disc into a bending motion and easily reducing the frequency of vibration, and a wave transmission using the plate-shaped vibrator. The purpose is to provide a vessel.

[0011]

A plate-shaped vibrator according to the present invention is a plate-shaped vibrator comprising a disk and an active disk bonded to the disk, wherein the disk is bonded to the active disk in the disk. A plurality of grooves are formed on the surface toward the outer peripheral direction from the center of the active disk body. The disk may be a metal disk having a depression on one surface, and the disk may have the plurality of grooves into which the active disk is fitted. Further, it is preferable to use a piezoelectric ceramic for the active disk.

Further, the transmitter according to the present invention is characterized in that the two plate-shaped vibrators are used and are connected to each other by a ring at the peripheral portion so that the active disks are on the outer surfaces. The ring may include two rings coupled to each plate-shaped vibrating body, and may have a structure in which a cross section of the coupling portion has an uneven shape.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A shows an example of a disk-shaped vibrator as one embodiment of the plate-shaped vibrator of the present invention.
And (B). FIG. 1A is a plan view of the plate-shaped vibrator of the present embodiment as viewed from the main surface side on which the active disc of the piezoelectric ceramic is mounted, and FIG. 1B is a plate-shaped vibrator. It is sectional drawing of the II 'plane of FIG.

In the present embodiment, a disk-shaped vibrator is used as the active disk 1. For example, a piezoelectric ceramic using a piezoelectric ceramic electromechanical energy conversion material such as a lead zircon titanate piezoelectric ceramic is used, and the metal disk 2 is a disk-shaped disk made of a metal such as an aluminum alloy. The main surface of the metal disk 2 has a depression of a corresponding shape such that the active disk 1 of a disk-shaped piezoelectric ceramic is fitted therein. The active disk 1 of the piezoelectric ceramic and the metal disk fitted in this recess are provided. 2 is firmly adhered to the contact surface, and its basic structure is almost the same as that of the conventional example.

The plate-shaped vibrator of the present embodiment is characterized in that the metal disk 2 is provided with a groove having a predetermined width and a predetermined depth radially from the center of the circular surface to which the active disc 1 of the piezoelectric ceramic is bonded. There. That is, as shown in FIG. 1 (A), a plurality of grooves 3 are formed in the radial direction from the center of the circular shape on the main surface side of the metal disk 2, so that the groove 3 is formed by the active disk of the piezoelectric ceramic. It has a structure that does not join with the body 1.

Next, the principle of driving the vibration of the plate-shaped vibrating body of this embodiment will be described.

As in the prior art, the active disk 1 of the piezoelectric ceramic has an electrode pattern (not shown) formed on substantially the entire main surface side and the rear side thereof, and a predetermined frequency between the two electrodes. A drive signal is applied. For this reason, the active disk 1 of the piezoelectric ceramic generates respiratory vibration in the radial direction, and as a result, the surface of the active disk 1 of the piezoelectric ceramic changes in area. Here, since the active disk of the piezoelectric ceramic is bonded to the metal disk 2, the change in the area of the active disk 1 of the piezoelectric ceramic expands and contracts the bonding surface of the metal disk 2 in the radial direction. The metal disk 2 is driven such that the bonding surface is bent in a vertical direction perpendicular to the metal disk 2 and generates bending vibration as in the conventional example. Here, in a structure in which the active disk 1 is bonded to the metal disk 2 on the entire surface as in the conventional example, in order to cause the plate-shaped vibrator to generate bending vibration, in addition to the radial driving of the piezoelectric ceramic 1, the circular vibration is applied. Since a driving force is also required in the circumferential direction, it is difficult to bend the disc and the displacement expansion efficiency is low.

In this embodiment, the metal disk 2
A plurality of grooves having a predetermined depth are formed in the radial direction on the bonding surface side of the active disk 1, and the grooves are not bonded to the active disk 1, and the metal is viewed from the active disk 1. The circular surface of the disk 2 is divided into a substantially rectangular and easily bendable fan-shaped plate, and a driving force for radial expansion and contraction works effectively, so that each fan-shaped plate can be bent efficiently.

Further, according to this configuration, since a plurality of grooves are formed as compared with the conventional metal disk 2 having no groove, the rigidity of the metal disk is reduced as a whole, and the same driving force is exerted by the active disk 1. In contrast, it can be seen that the displacement of the bending vibration of the metal disk can be increased.

Further, generally, the vibration (resonance) frequency (f) of such a plate-like vibrator is f = (1 / 2π) (s /
m) ^1/2 (s: stiffness, m: equivalent mass). In the present embodiment, it is possible to reduce the s by reducing the elastic modulus of the metal disk by providing a groove in the metal disk. Since the vibration (resonance) frequency is reduced as can be understood from the above equation, the frequency of the plate-shaped vibrator can be reduced.

The tendency of the characteristics of the present embodiment as described above increases as the number of grooves formed in the metal disk increases.
It becomes more noticeable as the depth of the groove is increased.

FIGS. 2 and 3 show another embodiment of the present invention. FIG. 2 shows various forms of the arrangement or shape of the grooves formed in the metal disk 2.
Indicates various forms of the depth and shape of the groove. The bending mode of the plate-shaped vibrator can be controlled by combining the arrangement of such various grooves and the shape such as the depth direction. In general, bending vibration of a plate-shaped vibrator is basically uneven vibration that occurs in the medium direction around the center, so to increase this efficiency, the groove should be formed so that the depth of the groove also becomes deeper toward the center. It is valid.

FIG. 4 is a view showing an embodiment of the transmitter according to the present invention in which a transmitter is formed by using the two plate-shaped vibrators.

In the present embodiment, a metal disk 2 made of aluminum alloy or the like having a main surface depressed in a circular shape and having a plurality of grooves on the inner surface of the depression, and a disc-shaped piezoelectric ceramic vibrator (PZT) inside the depression The disk-shaped vibrating bodies in which the active disks 1 are attached are connected via metal rings 3 along the vicinity of the circumference of a metal disk 2 made of two high-strength materials so that the active disks 1 are on the outer surface sides. Adopted a structure that has been. As the detailed shape and structure of the metal ring, two rings connected to each active disk body 1 are used, and the connecting portion of each ring has a concave and convex portion having a circular cross section that is engaged with each other and has a circular cross section. Have.

In the structure of the above embodiment, a drive signal is applied between the electrodes to the active disc 1 of the piezoelectric ceramic of each active disc 1 so that radial expansion and contraction vibrations are generated synchronously. This causes the plate-shaped vibrator to generate bending vibration. The metal disk 2 is formed by the uneven structure of the metal ring.
Of the active disk 1 and the metal disk 2
And high power can be efficiently obtained. In the present embodiment, since each disk-shaped vibrator employs the groove structure provided in the metal disk 2, the rigidity of the metal disk 2 is reduced, and bending motion is likely to occur. Is reduced in frequency, and very good vibration characteristics can be obtained.

In the above-described embodiment, the shape of the active disk has been described as being circular. However, the active disk may have an elliptical shape or a shape close to a rectangle that causes spread vibration. Further, it is apparent from the above principle that the active disk is not limited to a single body but may be divided into a plurality of portions as long as the active disk has a configuration that causes spreading vibration. As the material of the metal disk, stainless steel and other metals can be used in addition to the aluminum alloy.

[0027]

According to the present invention, since a plurality of grooves are provided on the joint surface of the disk with the active disk, the radial movement of the active disk is efficiently transmitted to the disk and bent. Motion easily occurs and higher power can be achieved by the same drive signal. In addition, the rigidity of the disk is reduced, and the vibration frequency can be reduced, so that good vibration characteristics can be obtained. Further, since the plate-shaped vibrator has a simple structure, a thinner and lighter transmitter can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of the present invention. FIG. 1A is a plan view seen from the main surface of the plate-shaped vibrating body,
FIG. 1B is a cross-sectional view taken along the line II ′.

FIG. 2 shows various forms of arrangement of grooves of a metal disk of the present invention.

FIG. 3 shows various forms of the depth and shape of the groove of the metal disk of the present invention.

FIG. 4 is a diagram showing an embodiment of the transmitter of the present invention.

FIG. 5 is a view showing a conventional plate-shaped vibrating body.

[Explanation of symbols]

 1 Piezoelectric ceramic 2 Metal disk 3 Metal ring 4 Groove

Claims (5)

[Claims] 1. A plate-shaped vibrating body comprising a disk and an active disk adhered to the disk, wherein a surface of the disk to be bonded to the active disk is directed outward from a center of the active disk. A plate-shaped vibrating body characterized in that a plurality of grooves are formed in the vibrator. 2. A plate-shaped vibrating body comprising a metal disk having a depression on one surface and an active disk body fitted into the depression of the metal disk, wherein a bonding surface of the metal disk with the active disk body in the depression is provided. A plate-shaped vibrator in which a plurality of grooves are formed in a radial direction. 3. The plate-shaped vibrating body according to claim 1, wherein the active disk body is constituted by a piezoelectric ceramic. 4. The plate-like vibration according to claim 1, wherein the two plate-like vibrators are connected to each other by a ring at the periphery thereof such that the active disks are on the outer surfaces. Transmitter using body. 5. The ring according to claim 2, wherein said ring is connected to each plate-shaped vibrator.
5. The transmitter according to claim 4, wherein the transmitter comprises a plurality of rings, and a cross-section of a connecting portion has an uneven shape.