JPH0147079B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an ultrasonic sensor used as an ultrasonic transmitter or receiver.

[Background technology] Ultrasonic sensors used for transmitting and receiving ultrasonic waves are
In order to provide directivity for transmitting or receiving waves, conventionally, as shown in FIG. It was set up. Horn 3 is designed not only to provide narrow directivity, but also to provide wide directivity because, without horn 3, variations in microphone characteristics would appear as variations in directivity. However, the use of such a horn 3 inevitably led to an increase in size and could not meet the demand for miniaturization and resource saving.

[Objective of the Invention] The present invention has been made in view of the above points, and its purpose is to reduce the variation in the directivity due to the variation in the characteristics of the microphone, even though a separate horn is not required. An object of the present invention is to provide an ultrasonic sensor that can be miniaturized and save resources without causing such problems.

[Disclosure of the Invention] Accordingly, the present invention provides a structure in which the outer periphery of a microphone case provided with a vibrating piece at its tip is held by a cylindrical elastic body for vibration isolation, and the outer periphery of the vibrating piece at the tip of the microphone case is The feature is that a space is provided between the microphone case and the elastic body, and the space is provided between the tip of the microphone case and the cylindrical elastic body that holds the outer periphery of the microphone case. However, it is designed to prevent ultrasonic waves from going around and exhibit a predetermined directivity.

The present invention will be described below in detail based on the illustrated embodiment. As shown in FIG. It is said to be 5. As shown in FIGS. 1 to 3, the outer periphery of the microphone case 1 is provided with a cylindrical structure for vibration isolation, which quickly damps vibrations after the electric drive signal to the vibrating element 4 is stopped. An elastic body 2 is provided, and this elastic body 2 holds the microphone case 1.
A space 6 is provided between the outer circumference of the tip of the microphone case 1 and the inner circumference of the tip of the elastic body 2, making use of the fact that the outer circumference of the tip of the microphone case 1 is made into a tapered surface 5. The presence of the space 6 prevents ultrasonic waves from going around. In the case shown in FIG. 1, the inner diameter of the tip of the elastic body 2 is the same as the outer diameter of the microphone case 1, and the tip surface of the elastic body 2 is set back from the tip surface of the microphone case 1. , the volume of the space 6 is reduced. Also the second
In the case shown in the figure, the inner diameter of the inner peripheral surface of the tip of the elastic body 2 is made larger than the outer diameter of the microphone case 1, and a recess 7 is formed in the tip of the elastic body 2.
As a result, a space 6 having a diameter larger than the outer diameter of the microphone case 1 is formed. In this case, the outer periphery of the tip end of the microphone case 1 does not have to be the tapered surface 5. Furthermore, in the one shown in FIG. 3, the recess 7 provided at the tip of the elastic body 2 is eccentric with respect to the microphone case 1, and the space 6 in the upper part of the microphone case 1 in the figure is small. The space 6 at the bottom is made large so that the directivity is slanted to one side.

[Effects of the Invention] As described above, in the present invention, the outer periphery of the tip of the microphone case where the vibrating piece is disposed, and the tip of the cylindrical elastic body for vibration isolation that holds the outer periphery of the microphone case. A space is provided in between, and this space prevents the ultrasonic waves from going around, and although it has wide directivity, it can have directivity, and it is a device that has a characteristic of a microphone. Since variations do not appear as directivity variations and the elastic body functions as a horn, a separate horn is not required, making it possible to downsize and save resources.

[Brief explanation of drawings]

Figures 1a and b are sectional views and front views of one embodiment of the present invention, Figures 2 a and b are sectional views and front views of another example, and Figures 3 a and b are sectional views of yet another example. 4 is a sectional view of the same microphone case as above, and FIG. 5 is a sectional view of a conventional example, in which 1 is a microphone case, 2 is an elastic body, 4 is a vibrating piece, and 5
indicates a tapered surface, and 6 indicates a space.

Claims (1)

[Scope of Claims] 1. The outer periphery of a microphone case having a vibrating piece at its tip is held by a cylindrical elastic body for vibration isolation, and the outer periphery of the vibrating piece at the tip of the microphone case is connected to the microphone case. An ultrasonic sensor characterized by having a space between it and an elastic body. 2. The ultrasonic device according to claim 1, wherein the outer circumference of the tip of the microphone case is a tapered surface, and a space is formed between the tapered surface and the inner circumferential surface of the tip of the elastic body. sonic sensor.