JP3242183B2 - Drip-proof ultrasonic microphone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drip-proof ultrasonic microphone which is integrated with a transmitter and a receiver.

[0002]

2. Description of the Related Art A conventional drip-proof ultrasonic microphone is a transmission / reception integrated type driven by inputting a tone burst wave to a piezoelectric element such as piezoelectric ceramic at a constant or arbitrary cycle. It is configured as shown in FIG. The vibrating body A is formed by fixing the piezoelectric element 1 to the inner surface of the bottom of a vibrating case 2 having a tapered portion on the bottom side of a bottomed cylindrical shape. The vibration case 2 is formed of an aluminum material, and serves as one conductor when the piezoelectric element 1 is driven. The piezoelectric element 1 is formed of a PZT-based piezoelectric ceramic in a disk shape, and has electrodes on both surfaces. One surface of the piezoelectric element 1 is adhered to the bottom inner surface of the vibration case 2 with an adhesive, and a lead wire 7 on the + side is connected to the other surface. The terminal block 3 is formed in a disk shape on a printed circuit board, is fitted and fixed in a middle position in the vibration case 2, and prevents a change in resonance frequency when the straight pipe portion of the vibration case 2 is held. ing. The terminal block 3 has + and-terminals 9 and 10, and the terminals 9 and the lead wires 7 are electrically connected by a circuit on a printed circuit board. The terminal 10 is electrically connected to the vibration case 2 by a circuit on a printed circuit board. A sound absorbing material 5 made of a sound absorbing felt is provided between the piezoelectric element 1 and the terminal block 3 in the vibration case 2. An elastic body 4 is disposed in an opening at the upper end of the vibration case 2, and prevents the terminal block 3 from being excited by the vibration body A by the elastic body 4. Further, in the figure, 8 is a conductive adhesive, and 11 is solder.

[0003]

The above-described drip-proof ultrasonic microphone has the following problems when used for a human body detection sensor for an automatic door or a car detection sensor for a parking lot. . When the radial expansion and contraction of the piezoelectric element 1 described above is converted into longitudinal vibration by the vibrating body A, efficient amplitude cannot be obtained because the vibrating case 2 is a rigid body, and the output sound pressure level becomes low. It is in a state where it is impossible to detect an object at a distance. For this reason, there is a problem that an open ultrasonic microphone having no drip-proof structure is used as an element for a sensor for an automatic door and a sensor for a parking lot, though it is likely to be installed outdoors.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent long distance detection by mounting a resonator that amplifies longitudinal vibration of a vibrating body. A drop-type ultrasonic microphone is provided.

[0005]

According to a first aspect of the present invention, there is provided a drip-proof ultrasonic microphone according to the first aspect, wherein the vibrating case has a bottomed cylindrical shape and has a tapered portion on a bottom side.
And the piezoelectric element 1 fixed to the bottom inner surface of the vibration case 2
+ -Terminal 9, which is fixed in the middle of the vibration case 2,
In a drip-proof ultrasonic microphone comprising a terminal block 3 having an elastic member 4 for sealing the opening of the vibration case 2 and a sound absorbing member 5 provided between the piezoelectric element 1 and the terminal block 3. The resonator 12 is provided on the outer surface of the bottom of the vibration case 2.

[0008] A drip-proof ultrasonic microphone according to a second aspect is characterized in that a protection net 13 is provided on the front side of the resonator 12. A drip-proof ultrasonic microphone according to a third aspect is characterized in that an elastic body 14 is mounted around a resonator 12. According to a fourth aspect of the present invention, there is provided a drip-proof ultrasonic microphone in which an elastic body is attached to an open end of a conical cylindrical resonator.

According to a fifth aspect of the present invention, there is provided a drip-proof type ultrasonic microphone, wherein the projection portion is integrally formed from the center of the bottom outer surface of the vibration case.
6 protruding, and the resonator 12 is mounted on the projection 16. In the drip-proof ultrasonic microphone according to the sixth aspect, an opening 17 is provided at the center of the bottom of the vibration case 2 and a resonator shaft 18 integrally provided with the resonator 12 is provided in the opening 1.
7 and the resonator 12 is attached thereto.

In the drip-proof ultrasonic microphone according to the present invention, an opening 19 is provided so as to penetrate the center of the bottom of the vibration case 2 and the center of the piezoelectric element 1 so that the resonator 12 can be cut to a length that can be cut. The present invention is characterized in that a resonator shaft 20 is integrally provided and the resonator shaft 20 is fitted into an opening 19 to mount the resonator 12. The drip-proof ultrasonic microphone according to claim 8 is characterized in that the resonator 12 is attached to the outer surface of the bottom of the vibration case 2 by ultrasonic welding.

According to a ninth aspect of the present invention, there is provided a drip-proof type ultrasonic microphone, wherein the opening hole is provided so as to penetrate the center of the bottom of the vibration case, the center of the piezoelectric element, and the center of the resonator.
1 is characterized in that a connection shaft 22 having a length that can be cut is fitted.

[0010]

The drip-proof ultrasonic microphone according to claim 1 is
Vibration of the vibrating body A at the time of transmitting waves is amplified by the resonator 12 provided on the bottom outer surface of the vibration case 2 and at the same time, the efficiency of piezoelectric conversion at the time of receiving reflected waves is improved, so that a long-distance object can be easily detected. it can. In the drip-proof ultrasonic microphone according to the second aspect, the protection net 13 is provided on the front face of the resonator 12 to prevent the resonator 12 and the vibration case 2 from being damaged by an external impact, and to improve weather resistance. it can.

The drip-proof ultrasonic microphone according to the third aspect of the invention can reduce reverberation and improve short-distance detection performance by mounting the elastic body 14 around the resonator 12. The drip-proof ultrasonic microphone according to claim 4,
By attaching the elastic body 15 to the open end of the conical cylindrical resonator 12, reverberation can be reduced and short-range detection performance can be improved.

According to a fifth aspect of the present invention, there is provided a drip-proof ultrasonic microphone.
6 is provided in a protruding manner, and the resonator 12 is mounted on the projection 16, so that the holding strength of the resonator 12 can be improved. In the drip-proof ultrasonic microphone according to the sixth aspect, an opening 17 is provided in the center of the bottom of the vibration case 2, and a resonator shaft 18 provided integrally with the resonator 12 is fitted into the opening 17. 12
The holding strength of the resonator 12 can be improved by attaching the.

According to a seventh aspect of the present invention, there is provided a drip-proof ultrasonic microphone, wherein an opening hole is provided so as to penetrate the center of the bottom of the vibration case and the center of the piezoelectric element, and the resonator has a length which can be cut. The resonator shaft 20 is provided integrally and the resonator shaft 20 is fitted in the opening 19 and the resonator 12 is attached, so that the length of the resonator shaft 20 is adjusted by cutting, and the resonance frequency is adjusted. Can be adjusted.

In the drip-proof ultrasonic microphone according to the eighth aspect, the resonator holding strength can be improved by ultrasonically welding the resonator 12 to the bottom outer surface of the vibration case 2. The drip-proof ultrasonic microphone according to the ninth aspect has a length that can be cut into an opening hole 21 provided so as to penetrate the center of the bottom of the vibration case 2, the center of the piezoelectric element 1, and the center of the resonator 12. The resonance frequency can be adjusted by adjusting the length of the connection shaft 22 in the state of the completed drip-proof ultrasonic microphone by fitting the connection shaft 22 having the same.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment shown in FIG. 1 will be described.
Since the basic structure of the drip-proof ultrasonic microphone of the present invention is the same as that of the conventional example, substantially the same members are denoted by the same reference numerals, detailed description thereof will be omitted, and only essential parts will be described. I do. In the case of the present embodiment, the conical cylindrical resonator 12 is attached to the bottom outer surface of the vibration case 2 by bonding with an adhesive 23. This resonator 12 is adhered to the outer surface at the center of the bottom where the vertical vibration of the vibration case 2 is at its peak, and amplifies the vertical vibration by excitation from the vibration case 2 and simultaneously efficiently reflects the reflected wave from the reflecting object. Converted to vibration.

Next, a second embodiment shown in FIG. 2 will be described. As in the first embodiment, the resonator 12 is mounted, a cylindrical collar 24 is fitted around the outer periphery of the vibration case 2, and held by press-fitting or bonding. A metal protection net 13 such as a wire net is attached to the opening of the collar 24 on the front side of the side where the resonator 12 is mounted. By providing the protection net 13 on the front side of the resonator 12, the resonator 1 due to an external impact is provided.
2 and the vibration case 2 are prevented from being damaged.

Next, a third embodiment shown in FIG. 3 will be described. In the case of this embodiment, in the second embodiment, the resonator 12
And the outer periphery of the tapered portion of the vibration case 2 and the collar 24
The elastic body 14 is loaded in a portion surrounded by the inner periphery of the elastic member 14.
The elastic body 14 is formed of a member made of silicon or the like having a small change in viscoelasticity due to a change in temperature, suppresses unnecessary vibration of the resonator 12 at the time of amplitude, reduces reverberation, and enables detection of a short-distance object.

Next, a fourth embodiment shown in FIG. 4 will be described. An elastic body 15 is mounted between the opening edge of the resonator 12 and the tapered portion of the vibration case 2. This elastic body 15 also
It is formed of a member made of silicon or the like having a small change in viscoelasticity due to a temperature change, and suppresses unnecessary vibration at the time of the amplitude of the resonator 12, reduces reverberation, and enables detection of a short-range object.

Next, a fifth embodiment shown in FIG. 5 will be described. In the case of the present embodiment, an axial projection 16 is provided below the center of the bottom of the vibration case 2, an opening 25 is formed in the center of the resonator 12, and the projection 16 is formed as an opening. 2
5 and reinforced with an adhesive 23 for attachment. By attaching the resonator 12 in this manner, the holding strength of the resonator 12 can be improved.

Next, a sixth embodiment shown in FIG. 6 will be described. In the case of the present embodiment, an opening 17 is provided in the center of the bottom of the vibration case 2, and the resonator shaft 18 is integrated with the resonator 12.
Is provided. Then, the resonator shaft 18 is fitted in the opening hole 17, and after the fitting, it is reinforced by bonding with an adhesive 23.
The holding strength of the resonator 12 is stabilized. Next, a seventh embodiment shown in FIG. 7 will be described. An opening 19 is provided so as to penetrate the center of the bottom of the vibration case 2 and the center of the piezoelectric element 1, and a resonator shaft 20 having a cuttable length is provided integrally with the resonator 12. Then, the resonator shaft 20 is fitted into the opening hole 19, the length of the resonator shaft 20 is adjusted as required, and after the fitting, the reinforcement is reinforced by bonding with an adhesive 23. In this case, the holding strength of the resonator 12 can be improved, and the resonance frequency can be adjusted by adjusting the length of the resonator shaft 20.

Next, an eighth embodiment shown in FIG. 8 will be described. In the case of this embodiment, the resonator 12 is attached to the center of the outer surface of the bottom of the vibration case 2 by ultrasonic welding. 27 is a welding part. In this case, the metal bonding between the vibration case 2 and the resonator 12 can be stabilized, and the holding of the resonator 12 can be stabilized. Next, a ninth embodiment shown in FIG. 9 will be described. In the case of this embodiment, the center of the bottom of the vibration case 2
An opening 21 is provided so as to penetrate the center of the piezoelectric element 1 and the center of the resonator 12, and a connection shaft 22 having a cuttable length is fitted into the opening 21. 23 for reinforcement. In this case, the holding strength of the resonator 12 can be improved, and the resonance frequency in the completed product state of the drip-proof ultrasonic microphone can be adjusted by cutting the connecting shaft 22.

[0022]

According to the present invention, since the resonator is provided on the outer surface of the bottom of the vibration case as described above, the vibration of the vibrating body at the time of transmitting waves is amplified by the resonator provided on the outer surface of the bottom of the vibration case. In addition, the present invention can improve the piezoelectric conversion efficiency at the time of receiving a reflected wave, and can easily detect an object at a long distance.

Further, in the invention according to the second aspect of the present invention, since the protection net is provided on the front surface of the resonator, damage to the resonator and the vibration case due to an external impact is prevented and weather resistance is improved. You can do it. According to the third aspect of the present invention, since the elastic body is mounted around the resonator, the reverberation can be reduced and the short-range detection performance can be improved.

In the invention according to claim 4 of the present invention,
Since an elastic body was attached to the open end of the conical cylindrical resonator,
The reverberation can be reduced and the short-range detection performance can be improved. In the invention according to claim 5 of the present invention, since the projection is integrally provided from the center of the bottom outer surface of the vibration case and the resonator is mounted on the projection, the holding strength of the resonator can be improved. It is.

In the invention according to claim 6 of the present invention,
An opening is provided in the center of the bottom of the vibration case, and a resonator shaft integrally provided with the resonator is fitted into the opening to mount the resonator, so that the holding strength of the resonator can be improved. In the invention according to claim 7 of the present invention, an opening hole is provided so as to penetrate the center of the bottom of the vibration case and the center of the piezoelectric element, and the resonator shaft having a length that can be cut into the resonator is provided. Since the resonator is integrally provided and the resonator shaft is fitted in the opening, and the resonator is mounted, the resonance frequency can be adjusted by adjusting the length of the resonator shaft by cutting.

In the invention according to claim 8 of the present invention,
Since the resonator was ultrasonically welded to the bottom outer surface of the vibration case,
The resonator holding strength can be improved.
According to the ninth aspect of the present invention, a connection having a length that can be cut into an opening provided through the center of the bottom of the vibration case, the center of the piezoelectric element, and the center of the resonator. Since the shaft is fitted, the resonance frequency can be adjusted by adjusting the length of the connecting shaft in the state of the completed drip-proof ultrasonic microphone.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a second embodiment of the same.

FIG. 3 is a sectional view of a third embodiment of the same.

FIG. 4 is a sectional view of a fourth embodiment of the above.

FIG. 5 is a sectional view of the fifth embodiment of the above.

FIG. 6 is a sectional view of a sixth embodiment of the above.

FIG. 7 is a cross-sectional view of a seventh embodiment of the above.

FIG. 8 is a cross-sectional view of an eighth embodiment of the present invention.

FIG. 9 is a sectional view of a ninth embodiment of the above.

FIG. 10 is a sectional view of a conventional example.

[Explanation of symbols]

 A Vibration body 1 Piezoelectric element 2 Vibration case 3 Terminal block 4 Elastic body 5 Sound absorbing body 7 + lead wire 8 Conductive adhesive 9 + side terminal 10-side terminal 11 Solder 12 Resonator

Claims (9)

(57) [Claims] 1. A vibration case having a bottomed cylindrical shape and having a tapered portion on the bottom side, a piezoelectric element fixed to an inner surface of the bottom of the vibration case, and a piezoelectric element fixed in the middle of the vibration case.
In a drip-proof ultrasonic microphone including a terminal block having a terminal, an elastic body sealing an opening of the vibration case, and a sound absorbing body provided between the piezoelectric element and the terminal block, a bottom portion of the vibration case is provided. A drip-proof ultrasonic microphone, characterized in that a resonator is provided on the outer surface side of the microphone. 2. The drip-proof ultrasonic microphone according to claim 1, wherein a protection net is provided on the front side of the resonator. 3. The drip-proof ultrasonic microphone according to claim 1, wherein an elastic body is mounted around the resonator. 4. The drip-proof ultrasonic microphone according to claim 1, wherein an elastic body is attached to an opening end of the conical cylindrical resonator. 5. The drip-proof ultrasonic microphone according to claim 1, wherein a projection is integrally provided from the center of the bottom outer surface of the vibration case, and a resonator is mounted on the projection. 6. The resonator according to claim 1, wherein an opening is provided in the center of the bottom of the vibration case, and the resonator is mounted by fitting a resonator shaft integrally provided with the resonator into the opening. Drip-proof ultrasonic microphone. 7. An opening is provided so as to penetrate the center of the bottom of the vibration case and the center of the piezoelectric element, and a resonator shaft having a length that can be cut is provided integrally with the resonator, and the resonator shaft is connected to the resonator shaft. 2. The drip-proof ultrasonic microphone according to claim 1, wherein the resonator is attached by fitting into the opening. 8. The drip-proof ultrasonic microphone according to claim 1, wherein a resonator is attached to an outer surface of a bottom portion of the vibration case by ultrasonic welding. 9. A connection shaft having a cuttable length is fitted in an opening provided to penetrate the center of the bottom of the vibration case, the center of the piezoelectric element, and the center of the resonator. The drip-proof ultrasonic microphone according to claim 1.