JPS6117668Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultrasonic transducer used underwater, such as a depth sounder or a fish finder, and the embodiments shown in the drawings will be described below.

FIG. 1 shows an embodiment of the present invention, in which 1 is an ultrasonic transducer made of a lead zirconate titanate compound and polarized with electrode surfaces 1a and 1b formed by baking silver on both main surfaces; An acoustic reflecting member made of a porous material such as cork or foam rubber is disposed on the outer surface of the vibrator except for one electrode surface (1b side in the figure) which becomes the acoustic wave transmitting/receiving surface; 3 indicates both electrode surfaces 1a of the vibrator; ,1
4 is an insulating wire such as synthetic resin or rubber that liquid-tightly covers and protects a part of the vibrator 1, the acoustic reflection member 2, and the insulated wire 3. mold material, 5
indicates a protective case made of metal or hard synthetic resin that covers the outer surface of the molding material, and up to this point, it protects the ultrasonic transducer 1 equipped with the insulated wire 3 and the acoustic reflection member 2, as in the conventional case. After being set in the case 5, it is integrally formed by insert molding in which the welded material of the mold material 4 is injected.
In this example, the lower end surface of the protective case 5 covering the outer surface of the mold material 4 is cut out 5a over the entire surface.

Conventionally, underwater ultrasonic transducers are made by covering the outer surface of this type of insulating molded material with a protective case.
As shown by the dotted line, the lower end surface of the protective case 5 is on the same plane as the outer end surface of the bottom part 4a of the mold material 4, which serves as the wave transmission/reception surface for sound waves, so that the entire outer surface of the mold material is covered. On the other hand, since the bottom part 4a of the molding material needs to have a sufficient wall thickness to withstand water pressure, the lower end surface of the protective case inevitably falls within the directivity range θ of the sound waves, and part of the sound waves transmitted through the molding material. This has the disadvantage that the noise propagates and leaks into the protective case, which has a different acoustic impedance than the molding material, resulting in noise.

The above-mentioned drawbacks can be solved by increasing the diameter of the mold material and the protective case, but in this case, there was a dissatisfaction with the increase in size.

On the other hand, in the present invention, the mold material 4
By making a notch 5a in the lower end surface of the protective case 5 that covers the protective case, it can be positioned outside the directional range of the sound waves, so it is an excellent method for preventing the propagation and leakage of sound waves to the protective case without increasing the size. be effective.

Therefore, the notch 5a on the lower end surface of the protective case
is preferably as small as possible in order to prevent water pressure from the outer periphery from exerting an influence on the bottom 4a of the molding material, which serves as the wave transmission/reception surface for sound waves.However, as shown in another embodiment of the present invention in FIG. With the lower end surface flush with the bottom 4a of the mold material 4,
By forming the tapered notch 5a' on the inside of the lower end surface, it is possible to reliably prevent the propagation and leakage of sound waves to the protective case, and also to completely eliminate the influence of external water pressure.

[Brief explanation of the drawing]

1 and 2 are longitudinal cross-sectional views showing essential parts of the underwater ultrasonic transducer of the present invention. Note that the symbols in the figures indicate the same parts. 1... Ultrasonic transducer, 1a, 1b... Electrode surface,
2... Acoustic reflecting member, 3... Insulated wire, 4... Mold material, 5... Protective case, 5a, 5a'... Cut portion on lower end surface.

Claims (1)

[Scope of utility model registration request] An ultrasonic transducer, an acoustic reflecting member disposed on the outer surface of the transducer excluding the acoustic wave transmitting/receiving surface, and a portion of an insulated wire connected to electrode surfaces formed on both main surfaces of the transducer are arranged in a liquid-tight manner. A mold material coated with a mold material and a protective case covering the outer surface of the mold material, the lower end surface of the protective case is designed to prevent propagation and leakage of sound waves emitted from the vibrator to the lower end surface of the protective case. An underwater ultrasonic transducer characterized by having a part or the entire surface cut out.