JPS59120000A - Transmitter for depth - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an electroacoustic transducer used underwater, and particularly to a transmitter suitable for transmitting sound waves at depth.

[Prior art]

The conventional Langevin type transmitter, as shown in Figure 1,
Front mass 1. Piezoelectric element 2. The vibrator consisting of the rear mass 6 is connected to the case 5 by the support rubber 4 to maintain watertightness, and the vibration of the vibrator is transmitted to the case by utilizing the low stiffness of the support rubber. A configuration that prevents secondary acoustic radiation and keeps the amount of damping of the vibrator small is common. However, this configuration has the drawback that as the depth increases, the support rubber is compressed, and as the stiffness increases, the resonance frequency and electrical impedance change widely.

[Purpose of the invention]

An object of the present invention is to provide an electroacoustic transducer that can be used from shallow depths to deep depths where high water pressure is applied, and causes almost no change in electroacoustic characteristics as a transmitter.

[Summary of the invention]

In the transmitter shown in FIG. 1, the vibration amplitude is maximum at the front of the front mass on the front mass side, and at the back of the rear mass on the rear mass side, and there is a so-called vibration node where the vibration amplitude is zero at the piezoelectric element. There is, and the first thing to do is to follow
Firstly, support should be avoided at points where the vibration amplitude is large, and should be supported at the vibration nodes.Secondly, the front mass side of the vibration nodes should be entirely exposed to the sea and made of materials whose characteristics do not change due to water pressure. Sixthly, it is characterized by adopting a structure that does not emit unnecessary acoustic radiation. [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to FIG. 2. Second
In the figure, 11 is a metal front mass with one side (acoustic radiation surface side) closed of a hollow cylinder, 12 is a piezoelectric element, 15 is a rear mass, 14 is a front mass 11, a piezoelectric element 12. This is a support plate placed at the vibration node position of the vibration system of the rear mass 13. The front mass 11 and the support plate 14 are joined by welding or the like, and the support plate 14, the piezoelectric element 12, and the rear mass 13 are bonded. 15 is a watertight case to prevent water from coming into direct contact with the piezoelectric element 12 and the rear mass, and 16 is a cable for electrical connection with the piezoelectric element.

The piezoelectric element 1 is activated by the alternating voltage supplied from the cable 16.
2. The rear mass 13 system is driven, and this causes 1/4
A front mass 11 having a wavelength is excited and a sound wave is emitted. If the front mass 11 is made of a solid metal, vibration in the longitudinal direction will cause vibration in the radial direction of the cylinder perpendicular to this due to the Poisson's ratio of the material, and this radiation with an opposite phase will reduce the conversion efficiency. According to this embodiment, the amplitude in the radial direction becomes weak, which is efficient and has the effect of eliminating characteristic changes with depth.

〔Effect of the invention〕

According to the present invention, there is almost no distortion due to water pressure, changes in stay7ness, etc. in the part that comes in contact with water, and unnecessary acoustic radiation from parts other than the acoustic radiation surface of the front mass can be almost eliminated, so it is possible to It has the effect of minimizing changes in electroacoustic characteristics from deep to deep, and maintaining high electroacoustic conversion efficiency.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a general Langevin type transducer seen from the side, and FIG. 2 is a partial cross-sectional view of a wave transmitter according to an embodiment of the present invention seen from the side. 11...Front mass 12...Piezoelectric element 13...Rear mass 14...Support plate 15...Case 16...Cable exposure II ¥1 No.? figure

Claims (1)

[Claims] In a Langevin type vibrator consisting of a front mass, a piezoelectric element, and a rear mass, a support plate is provided between the Coulomb mass and the piezoelectric element, and the front mass is hollow and has a length equal to one quarter wavelength with respect to the resonance frequency. A transmitter for deep depth, characterized in that it is configured so that the entire resonance is 1/2 wavelength.