JPH07118838B2 - Transceiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has a transducer using a bolted Langevin oscillator, and in particular has a wideband receiving function in a low frequency region in addition to a transmitting / receiving function in a resonance frequency band. Active / passive sonar transmitter / receiver.

[Conventional technology]

Conventionally, in order to obtain a high acoustic output, a transducer for an active sonar has piezoelectric vibrators 1e to 1h as shown in Fig. 4 sandwiched between a front mass 2b and a rear mass 3b and tightened with a bolt 4b Langevin vibration. A child is used, and the front mass 2b is used by being supported by a rubber plate 15 that serves as a propagation path of sound waves and a cushioning material 14 that blocks vibration. 6b is a case, 7b is a spacer, 8b is a lid, 9c is an O-ring, 10b and 10c are screws, and 16 is a holding plate.

The bolted Langevin oscillator has a structure that is suitable for compensating the low tensile strength against the high compressive strength of the piezoelectric oscillator. By applying a compressive load to the piezoelectric oscillator with a bolt, the mechanical resonance point It has a structure that can withstand large amplitude vibrations in.

Then, by using the bolted Langevin oscillator near the primary resonance frequency of the longitudinal vibration, a transducer having a high conversion efficiency is configured.

Further, as shown in FIG. 5 (a), a conventional passive sonar receiver uses a cylindrical piezoelectric vibrator 17, and even a sound wave having a frequency lower than the resonance frequency f ₀ due to respiratory vibration,
The cylindrical piezoelectric vibrator 17 can be directly made to vibrate and vibrate, and flat received voltage sensitivity is obtained over a wide range of low frequencies as shown in FIG. 5 (b). 18a is a cap, 1
9 is a bolt, 20a and 20b are cushioning materials, and 21 is a mold.

[Problems to be solved by the invention]

However, since the transducer using the conventional bolted Langevin oscillator supports the front mass, vibrations in the frequency band of the passive sonar lower than the primary resonance frequency of longitudinal vibration are received from the front mass, which is the sound receiving surface. It could not be transmitted to the piezoelectric vibrator, and the sensitivity of the received voltage was too low to be used as a passive wave transmitter / receiver.

In addition, the transducer using the conventional cylindrical piezoelectric vibrator,
Since it is not possible to apply a compressive load like a bolted Langevin oscillator, the acoustic output is limited by the low tensile strength of the piezoelectric oscillator, so it is not suitable for a high output active sonar transducer.

An object of the present invention is to provide a transmitter / receiver having both active / passive functions.

[Means for solving problems]

In the present invention, the polarities of a plurality of piezoelectric vibrators are alternately laminated in reverse,
Front and rear masses are attached to both ends, and a transducer that uses a bolted Langevin transducer in which the front and rear masses are tightened and connected by bolts is a supporter that is provided in advance at the node of vibration in the primary resonance mode of longitudinal vibration. Supports the bolted Langevin vibrator with a casing structure that acoustically shields parts other than the front surface of the front mass, and electrically connects the electrodes of the same polarity of the piezoelectric vibrator in which the bolted Langevin vibrator is stacked in parallel. The positive and negative input terminals are connected to one electrode (for example, a negative electrode) while the other electrode (for example, a positive electrode) between the front mass and the supporter and the other electrode between the supporter and the rear mass (for example, a positive electrode) are connected. And an output end between the electrode and the transducer.

〔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, the piezoelectric vibrators 1a to 1d are laminated with the polarities alternately reversed via the supporter 5, the front mass 2a and the rear mass 3a at both ends are fastened with bolts 4a, and a static compressive stress σ ₀ is applied. The bolted Langevin oscillator constitutes the

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

All of the polarization-polarized negative electrodes (hereinafter referred to as negative electrodes) of the piezoelectric vibrators 1a to 1d are connected and drawn out to form a ground 13b, and the piezoelectric vibrator 1a between the front mass 2a and the supporter 5 is
The + electrode (hereinafter referred to as the + electrode) having the polarization polarity of 1d and the + electrode of the piezoelectric vibrators 1a to 1b between the supporter 5 and the rear mass 3a are connected and drawn out for each section, and the terminals 11a and 1 of the changeover switch 11 are connected.
They are connected to 1b respectively.

When the change-over switch 11 is connected to the S ₂ side, all the + electrodes are connected, that is, they are summed and drawn to the terminal 13a, and together with the terminal 13b, one of the longitudinal vibrations of the Langevin vibrator is generated.
It becomes the input / output terminal of the active transducer that transmits and receives sound near the next resonance frequency.

As shown in FIGS. 2 (a) to (c), the vibration mode at this time moves in the opposite directions of the front mass 2a and the rear mass 3a with the supporter 5 as a node, so that the piezoelectric vibrator 1a
In 1d, in-phase alternating stress is generated with static compressive stress σ ₀ as a reference, and in-phase voltage is induced. The piezoelectric vibrator is the sum connected, the sensitivity of the transducer has an overall length is λ _0/2 (λ ₀ bolting Langevin transducer as shown in the FIG. 2 (d) ~ (e) the Wavelength ) Is the maximum at the primary resonance frequency f ₀ of the longitudinal vibration. When the changeover switch 11 is connected to the S ₁ side, the + electrode is connected to the terminals 11a and 11b to the terminal 12
Directly connected to a and 12b, i.e. differentially connected, terminal 12a
And 12b are the output terminals of the passive wave receiver that receives in the low frequency band.

When a sound wave of a frequency lower than the primary resonance frequency of the longitudinal vibration is received from the front mass 2a by the differential connection, the front mass 2a and the rear mass 3a are driven by the sound pressure as shown in FIGS. 3 (a) to 3 (c). And move in the same direction via bolt 4a,
The piezoelectric vibrators 1a to 1d between the front mass and the supporter and the piezoelectric vibrators 1a to 1b between the supporter and the rear mass generate stresses in directions opposite to each other and induce voltages in phases opposite to each other. Since 12b and 12b are differentially connected, a stable flat received voltage sensitivity characteristic is obtained over a wide range of low frequencies as shown in FIG. 3 (d).

However, at the primary resonance frequency f ₀ of the longitudinal vibration, stress in the same direction is generated in all of the piezoelectric vibrators 1a to 1d, so that the voltage generated in the piezoelectric vibrators 1a to 1b and the voltage generated in the piezoelectric vibrators 1a to 1d are generated. Since the voltage and the voltage cancel each other out, the receiving sensitivity is significantly reduced.

〔The invention's effect〕

As described above, in the transducer of the present invention, the polarities of a plurality of piezoelectric vibrators are alternately laminated in reverse, the front mass and the rear mass are attached to both ends of the piezoelectric vibrator, and the front mass and the rear mass are fastened with bolts to connect the bolts. The Langevin vibrator is supported at the node of the vibration in the first resonance mode of the longitudinal vibration of the Langevin vibrator by bolts, which are supported in advance by the supporter, and the electrodes of the laminated piezoelectric vibrator are electrically connected in parallel to each other. And the other electrode (+ electrode in the embodiment according to the present invention) between the front mass and the supporter and the other electrode between the supporter and the rear mass in a state in which one electrode (-electrode in the embodiment according to the present invention) is all connected. The output terminal between the two is switched by a changeover switch to create a sum connection and a difference connection. It becomes a high-output active transceiver with high conversion efficiency near the frequency, and it becomes a passive transceiver that can obtain flat receiving voltage sensitivity over a wide range of low frequencies. There is an effect that can be a wave instrument.

[Brief description of drawings]

Figure 1 is a longitudinal sectional view showing an embodiment of a transducer according to the present invention, FIG. 2 (a) ~ (c) is the change-over switch of FIG. 1 S ₂
Of the first resonance mode of longitudinal vibration of the bolted Langevin oscillator when connected to the side, (d) is a transmitted voltage sensitivity characteristic diagram, (e) is a received voltage sensitivity characteristic diagram, FIG. 3 (A) to (c) are vibration state diagrams of the bolted Langevin oscillator when the changeover switch of FIG. ₁ is connected to the S ₁ side, (d) is a received voltage sensitivity characteristic diagram, and FIG. 4 is conventional. FIG. 5A is a vertical cross-sectional view showing an example of an active sonar transducer / receiver using the bolted Langevin transducer of FIG. 5, FIG. 5A is a longitudinal sectional view of an example of a conventional passive sonar transducer / receiver,
(B) is a received voltage sensitivity characteristic diagram. 1a to 1h, 17 ... Piezoelectric vibrator, 2a, 2b ... Front mass, 3a, 3b
… Rear mass, 4a, 4b, 19… Bolts, 5… Supporters, 6a, 6
b ... case, 7a, 7b ... spacer, 8a, 8b ... lid, 9a, 9b ... O-ring, 10a-10c ... screw, 11 ... changeover switch, 12a, 12b, 13
a ... terminal, 13b ... ground, 14,20a, 20b ... buffer material, 15 ... rubber plate, 16 ... holding plate, 18a, 18b ... cap, 21 ... mold

Claims (1)

[Claims] 1. A transmission / reception using a bolt-tightened Langevin vibrator in which polarities of a plurality of piezoelectric vibrators are alternately laminated to each other, a front mass and a rear mass are attached to both ends of the piezoelectric vibrators, and the front mass and the rear mass are tightened and connected by bolts. In the wave instrument,
A casing structure that supports the vibration nodes in the first resonance mode of the longitudinal vibration of the bolted Langevin oscillator with a supporter and acoustically shields other than the front surface of the front mass,
The piezoelectric vibrator has an input terminal in which electrodes of one polarity are connected in parallel, a terminal connected between the front mass and the supporter of the other polarity, and a terminal connected between the supporter and the rear mass. Transceiver.