JPS62250800A - Transmitter-receiver - Google Patents

Abstract

PURPOSE:To attain multiplex functions for both active and passive uses by laminating plural piezoelectric oscillators with their polarities alternate with each other. CONSTITUTION:The piezoelectric oscillators 1a-1d are laminated with their polarities alternate with each other via a supporter 5, and a front mass 2a and a rear mass 3a at both ends are tightened with a bolt 4a, and thus constitute a Langevine oscillator being applied with a static compressing stress sigma0 by the tightening of the bolt. Only the front surface of the front mass 2a contacts the external acoustic medium, and the sound transmission or the sound reception is executed through the front mass 2a. All negative electrodes are ocnnected with each other, drawn out, and grounded 13b. Positive electrodes are connected in two blocks, drawn out, and connected to the terminals 11a and 11b of a changeover switch 11 rspectively. When the switching switch 11 is connected to an S2-side, the electrodes are connected in sum connection and drawn out to a terminal 13a, and made the I/0 terminal of an active transmitter- receiver. When the switching switch 11 is connected to an S1-side, the electrodes are connected in difference connection, and the terminals 12a and 12b are made to the output terminals of a passive receiver that receives the wave in low frequency band.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a transducer using a bolted Langevin oscillator, and in particular, a transducer that combines a transceiver function in a resonant frequency band as well as a wide band receiving function in a low frequency region. Related to active/passive sonar transducers.

[Conventional technology]

Conventionally, transducers for active sonar use piezoelectric vibrators 18 to 1 h as shown in Fig. 4 to obtain high acoustic output.
is sandwiched between the front mass 2b and the rear mass 3b, and using a bolted Langevin oscillator tightened with bolts 4b,
The front mass 2b was supported by a rubber plate 15 serving as a propagation path for sound waves and a buffer material 14 blocking vibrations. 6
b is the case, and 7b is the spacer.

8b is a lid, 9c is an O-ring, 10b and 10c are screws, and 16 is a holding plate.

The bolted Langevin resonator has a structure suitable for compensating the low tensile strength for the high compressive strength of the piezoelectric resonator, and by applying a compressive load to the piezoelectric resonator with bolts, the mechanical resonance point is It has a structure that can withstand large amplitude vibrations.

By using the bolted Langevin oscillator near the first-order resonance frequency of longitudinal vibration, a transducer with high conversion efficiency is constructed.

In addition, the conventional receiver for passive sonar is shown in Figure 5 (
As shown in a), using the cylindrical piezoelectric vibrator 17, even a sound wave with a frequency lower than the resonant frequency f0 due to respiratory vibration can directly cause the cylindrical piezoelectric vibrator 17 to vibrate. As shown in (b), a flat reception voltage sensitivity is obtained over a wide range of low frequencies. 18a is a cap, 19 is a bolt, 20a and 20b are cushioning materials, 21
is a mold.

[Problem that the invention seeks to solve]

However, since conventional transducers using bolted Langevin transducers support the front mass, vibrations in the passive sonar frequency band lower than the primary resonance frequency of longitudinal vibration are transmitted from the front mass, which is the sound receiving surface. The signal could not be transmitted to the piezoelectric vibrator, and the received voltage sensitivity became too low to be used as a passive transducer.In addition, the conventional cylindrical piezoelectric vibrator was used to transmit and receive waves. The vessel is
Unlike bolted Langevin transducers, compressive loads cannot be applied, and the piezoelectric transducer's low tensile strength limits its acoustic output, making it unsuitable for high-output active sonar transducers.

An object of the present invention is to provide a transducer having multiple active/passive functions.

[Means for solving problems]

The present invention stacks a plurality of piezoelectric vibrators with alternating polarities,
In a transducer using a bolted Langevin oscillator, a front mass and a rear mass are attached to both ends, and the front mass and rear mass are connected by tightening bolts.
The bolted Langevin oscillator is supported by a supporter installed in advance at the vibration node in the first resonance mode of longitudinal vibration, and the casing structure is acoustically damped except for the front surface of the front l-mass. The positive and negative input terminals are electrically connected in parallel with the electrodes of the same polarity of the stacked piezoelectric vibrators, and one electrode (for example, the negative voltage I
and the other electrode (for example, the positive electrode) between the front mass and the supporter with the f ri connected.

This is a transducer characterized by having an output end between a supporter and the other electrode (for example, a positive electrode) between the rear mass.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, piezoelectric vibrators 1a''ld are stacked with opposite polarities via supports 5, and the front mass 2a and rear mass 3a at both ends are tightened with bolts 4a to reduce static compressive stress σ. Added bolts make up the Langevin oscillator.

The supporter 5 located at the node of the bolted Langevin oscillator is fixed by the case 6a, the spacer 7a, and the lid 8a, contacts the external acoustic medium only in the front of the front mass 2a, and transmits or receives sound through the front mass 2a. do. 9a and 9b are O-rings, and 10a is a screw.

All polarized electrodes (hereinafter referred to as -electrodes) of the piezoelectric vibrators 1a to 1d are connected and drawn out to form a ground 13b, and the polarization of the piezoelectric vibrators 10 to 1d between the front mass 2a and the supporter 5 is A piezoelectric vibrator 18 ~ between the polar live electrode (hereinafter referred to as ten electrodes), the supporter 5, and the rear mass 38
The live electrodes 1b are connected and drawn out for each section, and are connected to terminals 11a and 11b of the changeover switch 11, respectively.

When the changeover switch 11 is connected to the 82 side, all the live electrodes are connected, that is, they are phase connected and the terminal 13a
Together with the terminal Llb, it becomes the input/output terminal of an active transducer that transmits and receives sound near the first-order resonance frequency of the longitudinal vibration of the Langevin oscillator.

At this time, the vibration mode is such that the front mass 2a and the rear mass 3a move in opposite directions with the supporter 5 as a node, as shown in FIGS. 2(a) to 2(c). Static compressive stress σ. An alternating stress with the same phase is generated with reference to , and a voltage with the same phase is induced. Since the piezoelectric vibrators are phase-connected, the sensitivity of the transducer is determined by the total length of the bolted Langevin vibrator being λ, as shown in FIGS. 2(d) to (e). It reaches a maximum at the first-order resonance frequency f0 of longitudinal vibration, which is /2 (λ is the wavelength). Changeover switch 1
1 is connected to the 51 side, the raw electrode is connected to the terminal 11
They are directly drawn out from a and llb to terminals 12a and 12b, that is, they are differentially connected, and the terminals 12a and 12b serve as output ends of a passive wave receiver that receives waves in a low frequency band.

When a sound wave with a frequency lower than the first resonance frequency of longitudinal vibration is received from the front mass 2a by differential connection, the front mass 2a is moved by the driving force due to the sound pressure as shown in FIGS. 3(a) to (c).
Since the rear mass 3a and the front mass 3a move in the same direction via the bolt 4a, the piezoelectric vibrator 10 between the front mass and the supporter
~1d and the piezoelectric vibrator 18 between the supporter and the rear mass~
lb, stresses in opposite directions are generated and voltages with opposite phases are induced, but since the terminals 12a and 12b are differentially connected, a low frequency wide band is generated as shown in Figure 3 (4). The received voltage sensitivity characteristics are stable and flat over the period of time.

However, the primary resonance frequency f of longitudinal vibration. Since stress is generated in the same direction in all of the piezoelectric vibrators 1a to 1d, the voltage generated in the piezoelectric vibrators 18 to 1b and the piezoelectric vibrator 1c are
Since the voltage generated at =ld cancels each other out, the reception sensitivity is significantly reduced.

〔Effect of the invention〕

As explained above, in the transducer of the present invention, a plurality of piezoelectric vibrators are stacked with their polarities alternately reversed, a front mass and a rear mass are attached to both ends of the piezoelectric vibrator, and the front mass and rear mass are connected by bolts. The Langevin oscillator is supported by bolts with a supporter installed in advance at the vibration node in the first resonance mode of the longitudinal vibration of the Langevin oscillator, and the electrodes of the stacked piezoelectric oscillators are electrically connected in parallel for input/output. The other electrode (live electrode in the embodiment according to the present invention) between the front mass and the supporter is connected between the end and one electrode (one electrode in the embodiment according to the present invention) and between the supporter and the rear mass. Since the output end between the other electrode and the other electrode is switched using a changeover switch to create phase connection and differential connection, conversion efficiency is high near the primary resonance frequency of the longitudinal vibration of the bolted Langevin oscillator, resulting in high output. It can be used as an active transducer, and it can also be used as a passive receiver that can obtain flat reception voltage sensitivity over a wide range of low frequencies, making it an active/passive multifunctional transducer. .

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a transducer according to the present invention, and FIGS. 2(a) to (c) show that the changeover switch in FIG.
Vibration state diagram of the first-order resonance mode of longitudinal vibration of the bolted Langevin oscillator when connected to the second side, ((1) is the transmitting voltage sensitivity characteristic diagram, (e) is the receiving voltage sensitivity characteristic diagram, 3
Figures (a) to (c) are vibration state diagrams of the bolted Langevin oscillator when the changeover switch in Figure 1 is connected to the 81 side, (d) is a received voltage sensitivity characteristic diagram, and Figure 4 is the conventional Fig. 5(a) is a vertical cross-sectional view of an example of a conventional passive sonar transducer using a bolted Langevin transducer;
b) is a delivery voltage sensitivity characteristic diagram. 1a to lh, 17... piezoelectric vibrator, 2a, 2b.
...Front mass, 3a, 3b...Rear mass, 4
a, 4b, 19...Pol 1-15...Supporter-1
6a, 6b-case, 7a, 7b-spacer, 8a.

Claims (1)

[Claims] (1) A transducer using a bolted Langevin oscillator in which multiple piezoelectric oscillators are stacked with alternate polarities, a front mass and a rear mass are attached to both ends, and the front mass and rear mass are connected by tightening bolts. In this case, the vibration node in the first resonance mode of the longitudinal vibration of the bolted Langevin vibrator is supported by a supporter, and the housing structure is designed to acoustically shield the area other than the front surface of the front mass, and one polarity of the piezoelectric vibrator is A transducer characterized by having an input terminal having electrodes connected in parallel, a terminal of the other polarity connected between the front mass and the supporter, and a terminal connected between the supporter and the rear mass.