JPH0576099A - Ultrasonic wave transmitter and receiver - Google Patents

Abstract

PURPOSE:To prevent the mechanical destruction of a vibrator without applying the tension on the vibrator even in the deep water. CONSTITUTION:An active pole 3 is arranged in an elliptic shell 1 in the ultrasonic transmitter and receiver. A cylindrical internal shell 2 with the octagon section is housed in the elliptic shell 1 with the both opening port terminals turned to a wall 1a in the short-axis direction of the elliptic shell 1. Simultaneously, the first side wall 2a of this internal shell 2 is linked to a side wall 1b in the longitudinal direction of the elliptic shell 1. The active pole 3 is arranged between the second side walls 2b of the internal shell 2. The stuck laminated direction of this active pole 3 is arranged in the axis direction of the elliptic shell 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic wave transmitter / receiver for transmitting and receiving in deep water.

[0002]

2. Description of the Related Art Among conventional ultrasonic wave transmitters / receivers, a flextensional type wave transmitter / receiver 30 disclosed in U.S. Pat. No. 3,277,433 is shown in FIG. There is. The wave transmitter / receiver 30 includes an elliptical shell 31, an active columnar body 32 laminated in the major axis direction of the elliptical shell 31, and an end piece 33 connecting both ends of the active columnar body 32 and the inner wall of the elliptical shell 31. Has been done. In the operation of the wave transmitter / receiver 30, the longitudinal vibration of the active columnar body 32 is transmitted to the elliptical shell 31 via the end piece 33, and the elliptical shell 31 bends and vibrates to emit sound waves into the water. Here, since the piezoelectric ceramic or the magnetostrictive material forming the active columnar body 32 is weak against tensile stress, a compressive force is applied to the vibrator in advance in order to cancel the tensile stress that acts on the vibrator during excitation.

[0003]

However, as shown in FIG. 4, when hydrostatic pressure F ₀ is applied to the elliptical shell 31, tension F ₁₀ acts in the major axis direction of the elliptical shell 31 due to the nature of the elliptical shape. Then, it acts as a tensile stress on the active columnar body 32 via the end piece 33. Therefore,
In deep water, when the transducer is driven, if the sum of the tension due to the hydrostatic pressure and the tension due to the excitation exceeds the limit of the tensile stress of the transducer, mechanical breakdown occurs in the transducer. there were.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic transducer which does not exert a tensile stress on a vibrator even in deep water.

[0005]

In order to achieve the above object, the present invention provides an ultrasonic transducer in which an active columnar body is arranged in an elliptical shell, wherein an elliptical shell has a cylindrical inner shell, The first side wall of the inner shell, which does not hold the active columnar body, is connected to the long side wall of the elliptical shell, while the open side ends of the elliptical shell are connected to the short side wall of the elliptical shell. The second side wall for holding the columnar body is arranged in the axial direction of the elliptical shell. Further, in the invention according to claim 2, the inner shell is a tubular shape having an octagonal cross section,
The active columnar body is composed of a piezoelectric ceramic or a magnetostrictive vibrator.

[0006]

According to the first aspect of the present invention configured as described above, even when tension acts in the major axis direction of the elliptical shell due to hydrostatic pressure, a compressive force acts on the active columnar body by the inner shell. In addition, the vibration amplitude is doubly amplified by the bending motion of the inner shell and the elliptical shell. Further, in the present invention according to claim 2 configured as described above, the internal shell having an octagonal cross section acts on the active columnar body of the piezoelectric ceramic or the magnetostrictive vibrator by using the tension in the major axis direction of the elliptical shell as a compressive force. Let

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes an elliptic shell in the shape of an elliptic cylinder, the upper and lower open ends of which are sealed by a watertight cover (not shown).

Reference numeral 2 denotes a cylindrical inner shell having an octagonal cross section, which is housed in the elliptical shell 1. The inner shell 2 has a first side wall 2a, which has an open end directed toward the short-axis direction side wall 1a of the elliptical shell 1 and does not hold an active columnar body 3 to be described later, and a long-side direction side wall 1b of the elliptical shell 1.
To hold the active columnar body 3
The side wall 2b is located in the axial direction perpendicular to the major axis direction of the elliptical shell 1. Also, on the upper surface of the inner shell 2,
Reference numeral 5 is a prestress bolt for applying a compressive force to the active columnar body 3 in advance, and reference numeral 6 is a through hole used for positioning the inner shell 2 and attaching a watertight cover (not shown).

Reference numeral 3 is an active columnar body in which piezoelectric ceramics or magnetostrictive vibrators are laminated, and the stacking direction thereof is aligned with the opening end direction which is the axial center direction of the elliptical shell 1, and the second side wall 2b of the inner shell 2 is formed. It is arranged in between. Reference numeral 7 is an electrode of each piezoelectric ceramic, 8 is a lead wire for supplying an AC electric signal to the active columnar body 3, and 9 is a spring electrode for conducting to each piezoelectric ceramic.

Next, the operation of this embodiment will be described.
First, when an AC electric signal is input to the active columnar body 3, longitudinal vibration is excited. The vibration amplitude generated from the active columnar body 3 is transmitted to the inner shell 2 in contact with both ends, amplified by the bending motion of the inner shell 2, and further transmitted to the elliptical shell 1 via the end piece 4. And
Even in the elliptic shell 1, the bending amplitude amplifies the vibration amplitude again to obtain a large amplitude.

Further, as shown in FIG. 2, when hydrostatic pressure F ₀ acts on the elliptical shell 1 in deep water, the elliptical shell 1 extends in the direction of its major axis and the first side wall 2a of the inner shell 2 is extended. It acts as a tension F _{1 on} the contact surface with the end piece 4. This tension F ₁ is, as shown in FIG. 3, a compression force F ₂ that vertically compresses the second side wall 2b of the inner shell _2.
Acts on the active columnar body 3. Therefore, even in deep water, due to hydrostatic pressure, the tension does not act on the active columnar body 3 but acts as a compressive force.
Mechanical destruction is prevented.

In the above embodiment, the cross-sectional shape of the inner shell 2 is octagonal, but if the cross-sectional shape is such that tension is applied in one direction and a compressive force acts in a direction perpendicular to that direction, Other common shapes other than octagons, such as ellipses, can be used.

[0013]

As described above, according to the present invention as set forth in claim 1, by providing the cylindrical inner shell between the elliptical shell and the active columnar body, the hydrostatic pressure acts in the major axis direction of the elliptical shell. Since the tension acts on the active columnar body as a compressive force, the active columnar body is not mechanically broken by the tensile stress even in deep water. Also, since the inner shell and the elliptical shell are made to do double bending motion,
The vibration amplitude is significantly amplified. Further, according to the present invention of claim 2, the tension in the major axis direction of the elliptical shell efficiently acts as a compressive force on the active columnar body such as the piezoelectric ceramic due to the inner shell having an octagonal cross section.

[Brief description of drawings]

FIG. 1 is a perspective view showing an ultrasonic wave transmitter / receiver according to an embodiment.

FIG. 2 is a plan view for explaining the action of the above force.

FIG. 3 is a cross-sectional view explaining the action of the above force.

FIG. 4 is a plan view showing the action and structure of a force of a conventional example.

[Explanation of symbols]

 1 Elliptical shell 1a Short side wall 1b Long side wall 2 Inner shell 3 Active columnar body 4 End piece

Claims (2)

[Claims] 1. An ultrasonic transducer in which an active columnar body is arranged in an elliptical shell, wherein a cylindrical inner shell is oriented in the elliptical shell so that both open ends of the cylindrical inner shell are directed toward the side wall in the minor axis direction of the elliptical shell. A first side wall of the inner shell which does not hold the active columnar body and is connected to the longitudinal side wall of the elliptical shell, while the second side wall which holds the active columnar body is connected to the axial center of the elliptical shell. An ultrasonic wave transmitter / receiver, which is arranged in a direction. 2. The ultrasonic transducer according to claim 1, wherein the inner shell has a tubular shape with an octagonal cross section, and the active columnar body is made of a piezoelectric ceramic or a magnetostrictive oscillator.