JPH0749915Y2 - Ultrasonic transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an ultrasonic transducer used for a back sensor or the like of an automobile.

(Prior Art) Conventionally, a drip-proof airborne ultrasonic transducer having a structure as shown in FIG. 4 has been used for a back sensor of an automobile.

In the above-mentioned drip-proof airborne ultrasonic transducer, the piezoelectric element 3 is attached to the inner surface of the ceiling portion 2a of the space 2 formed in the aluminum case member 1, while the inner diameter of the case member is larger than that of the space 2. The sound absorbing material 5 and the base plate 6 are sequentially fitted into the opening 4 of 1 and sealed with the resin sealing material 7. The electrode 3a of the piezoelectric element 3 is drawn out to the pin terminal 9 attached to the base plate 6 through the lead wire 8. The other electrode 3b of the piezoelectric element 3 is attached to the ceiling portion 2a of the space inside the case member 1 with a conductive adhesive, and is attached to the case member 1 and the case member 1 and the base plate 6. It is drawn out to the pin terminal 10 through a conductive paint 11 which electrically connects with one pin terminal 10.

By the way, the drip-proof airborne ultrasonic transducer
Although the bending vibration of the ceiling portion 2a of the space 2 in the case member 1 is utilized, the conventional drip-proof aerial ultrasonic transducer attenuates the leakage of the bending vibration, and therefore the case member 1 as a whole. It is necessary to increase the height of the above and increase the wall thickness of the supporting portion 1a of the case member 1 supporting the ceiling portion 2a. further,
In order to absorb the leakage of the bending vibration, the opening 4 of the case member 1 is sealed by the resin sealing material 7 having elasticity, while the case member 1 needs the sound absorbing material 5 to absorb the internal resonance. To do. For this reason, the drip-proof airborne ultrasonic transducer of FIG. 4 has a large shape, has a complicated structure, and is troublesome to assemble.

(Object of the Invention) An object of the present invention is to provide a drip-proof ultrasonic transducer that is thin, has a simple structure, and is easy to assemble.

Therefore, according to the present invention, a sheet-shaped elastic body is arranged along the node line on the front side of the diaphragm, and an anisotropic conductive rubber sheet is arranged so as to cover the back side of the diaphragm. The upper and lower open end portions of the case member are bent over the peripheral edge of the elastic body and the peripheral edge of the base plate disposed below the anisotropic conductive rubber sheet, and the diaphragm has its node. The elastic member is elastically supported by a line between the elastic body and the anisotropic conductive rubber sheet, and the vibrating plate has a bonding portion of the piezoelectric element protruding outside the case member, and the thickness of the protruding portion is changed. The feature is that the frequency adjustment is performed by using this. One electrode of the piezoelectric element electrically conductively adhered to the substantially central portion of the diaphragm is drawn out to the terminal portion of the base plate through the diaphragm and the anisotropic conductive rubber sheet, and the other electrode of the piezoelectric element is also provided. Is drawn out to the other terminal portion of the base plate through the anisotropic conductive rubber sheet.

According to the present invention, the upper and lower opening ends of the case member are bent inward, and the diaphragm is different from the sheet-like elastic body at the node line between the upper and lower opening ends. Since it is elastically supported from both sides by one-sided conductive rubber sheet, the vibration leakage of the vibration plate is reduced, there is no need for members etc. to absorb this vibration leakage, and the structure is simple and the thin type is easy to assemble. It is possible to obtain a drip-proof ultrasonic transducer whose inside is sealed. Further, according to the present invention, since both electrodes of the piezoelectric element are electrically connected to the terminal portion provided on the base plate by the anisotropic conductive rubber sheet, the electrode of the piezoelectric element and the terminal portion of the base plate are connected to the ultrasonic transducer. It is possible to conduct electricity at the same time as assembling, and the wiring of the electrode of the piezoelectric element becomes unnecessary.

Further, according to the present invention, since the portion where the piezoelectric element of the vibration plate is adhered is protruded to the outside of the case member, the frequency after assembly is adjusted by adjusting the thickness of this protruding portion of the vibration plate. It is also possible to use as a waterproof ultrasonic transducer with little deterioration in characteristics even if water droplets adhere to the large amplitude portion of the vibration plate protruding to the outside of the case member. In addition, the elastic body can be easily positioned, and the piezoelectric element can be easily positioned.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1, a vibration plate 21 having a piezoelectric element 20 bonded to a central portion thereof and performing bending vibration has a supporting portion 21 including a node line (not shown) located inside a peripheral edge portion 21a thereof.
At b, the sheet side elastic body 22 having elasticity such as rubber and the anisotropic conductive rubber sheet 23 are elastically supported from the front side and the back side thereof. Above anisotropic conductive rubber sheet
An insulating base plate 24 having a diameter substantially equal to that of the vibrating plate 21 is arranged below the diaphragm 23, and the lower and upper open end portions of the case member 25 are provided on the base plate 24 and the elastic body 22. 25a and 25b are respectively folded. A coil spring-shaped first spring terminal 26 and a leaf spring-shaped second spring terminal 27 are both elastically deformed between the base plate 24 and the anisotropic conductive rubber sheet 23. ing.

The vibrating plate 21 is a metal plate (not shown) such as stainless steel.
Is punched into a disc shape, and the inside of the peripheral edge portion 21a is extruded in two steps in one step to have an outer shape as shown in FIG. The electrode 20a of the disk-shaped piezoelectric element 20 is adhered to the ceiling surface of the space 28 inside the protrusion 21c formed by extrusion molding of the diaphragm 21 with an adhesive.

On the other hand, the elastic body 22 has a ring shape that is fitted onto the protruding portion 21c of the diaphragm 21, and the support portion 21b is provided on the front side of the diaphragm 21.
Abut. Further, the anisotropic conductive rubber sheet 23 has a diameter that extends from the electrode 20b of the piezoelectric element 20 substantially along the inner surface of the protruding portion 21c of the diaphragm 21 to the supporting portion 21b of the diaphragm 21. This anisotropically conductive rubber sheet 23 is pressed against the supporting portion 21b of the diaphragm 21 by the spring force of the first spring terminal 26, and electrically connects the diaphragm 21 and the first spring terminal 26. The anisotropic conductive rubber sheet 23 is also pressed by the spring force of the second spring terminal 27 against the electrode 20b of the piezoelectric element 20 to electrically connect the electrode 20b and the second spring terminal 27.

Base plate located under the anisotropic conductive rubber sheet 23
24 is made of an insulating material such as glass epoxy, and a pattern 29 for electrically connecting the first spring terminals 26 is formed on the main surface 24a facing the anisotropic conductive rubber sheet 23. There is. On the other main surface 24b of the base plate 24, terminal patterns 29a and 30 functioning as terminals are formed. Terminal pattern 29a and pattern 2
The 9 and 9 are electrically connected to each other by the through hole film 31a of the through hole 31 formed in the base plate 24. In addition, the base plate 24 has claws 27a formed on the second spring terminal 27,
Insertion holes 32, 32 for inserting 27a and soldering to the terminal pattern 30 are formed.

The upper end surface and the lower end surface of the first spring terminal 26 are parallel to each other, and the upper end surface and the lower end surface are evenly applied to the anisotropic conductive rubber sheet 23 and the main surface 24a of the base plate 24, respectively. The thickness is gradually reduced at the upper and lower portions so that they are pressed against each other.

Also, the second spring terminal 27 has both ends of the claws 27a, 27a formed at the center of the spring piece having a constant width bent to the same side, and arcuate contact portions 27b, 27b are formed at both ends. It was done.

The elastic body 22, the vibrating plate 21 in which the piezoelectric element 20 is bonded to the ceiling surface of the projecting portion 21c, the anisotropic conductive rubber sheet 23, and the base plate 24 have the upper opening end 25b in advance in this order.
It is fitted into a cylindrical case member 25 that is bent inward at 0 degree or slightly larger than 0 degree, and the lower open end 25a of the case member 25 is bent onto the base plate 24.

It should be noted that the first spring terminal 26 is electrically conductively bonded to the pattern 29 of the base plate 24 by soldering or a conductive adhesive before being assembled in the case member 25.
Further, the claws 27a, 27a of the second spring terminal 27 are inserted into the insertion holes 32, 32 of the base plate 24, and the tip portions thereof are the base plate 24.
Is soldered to the terminal pattern 30 of. This soldering is
After assembling the base plate 24 into the case member 25, it may be performed at the same time as the soldering process of the terminal patterns 29a, 30 by dip soldering or the like.

With such a configuration, the spring force of the first spring terminal 26 and the second spring terminal 27 acts on the diaphragm 21,
The diaphragm 21 has an elastic body 2 on its support portion 21b including the node line.
2 and the anisotropic conductive rubber sheet 23 are pressed against each other and elastically supported by the elastic body 22 and the anisotropic conductive rubber sheet 23. Further, in the piezoelectric element 20, the electrode 20a thereof has a vibration plate 21
Through the anisotropically conductive rubber sheet 23 to the first spring terminal 26, and the first spring terminal 26 is connected to the base plate.
The electrode 20b is led out to the terminal pattern 29a of the base plate 24 through the through holes 31 of 24, and the other electrode 20b is conducted to the second spring terminal 27 through the anisotropic conductive rubber sheet 23. 24 terminal patterns 30
Be derived to.

Although the upper end surface of the first spring terminal 26 and the contact portions 27a, 27b of the second spring terminal 27 are both in pressure contact with the anisotropic conductive rubber sheet 23, the anisotropic conductive rubber sheet 23 has the thickness direction thereof. Since the first spring terminal 26 and the second spring terminal 27 are not electrically connected to each other through the anisotropically conductive rubber sheet 23, the first and second spring terminals 26 and 27 are not electrically connected to each other.

The ultrasonic transducer having the structure of FIG. 1 has a thickness of about the sum of the thickness of the sheet-shaped elastic body 22, the anisotropic conductive rubber sheet 23 and the base plate 24, and is thin and has drip-proof property. It is possible to obtain an ultrasonic transducer suitable for a back sensor of an automobile.

Further, since the protrusion 21c of the diaphragm 21 protrudes to the outside of the case member 25, the thickness can be changed by shaving the protrusion 21c from the outside, and the frequency of the ultrasonic transducer can be easily adjusted. .

The opening end 25b on the upper side of the case member 25 has a third
As shown in the drawing, the first elastic body 22 may be bent in the middle so as to evenly contact the first elastic body 22.

[Brief description of drawings]

1 is a longitudinal sectional view of an embodiment of the ultrasonic transducer according to the present invention, FIG. 2 is an exploded perspective view of the ultrasonic transducer of FIG. 1, and FIG. 3 is a modification of the ultrasonic transducer of FIG. FIG. 4 is a vertical sectional view showing the internal structure of a conventional ultrasonic transducer. 20 ... Piezoelectric element, 21 ... Vibration plate, 21a ... Peripheral part, 21b ... Support part, 21c ... Projection part, 22 ... Elastic body, 23 ... Anisotropic conductive rubber sheet, 24 ... Base plate, 25 ... Case member, 25a , 25b ... Open end, 29 ... Pattern, 29a, 30 ... Terminal pattern, 31 ... Through hole.

Claims (1)

[Scope of utility model registration request] 1. A vibrating plate made of metal, a piezoelectric element bonded to substantially the central portion of the vibrating plate to bend and vibrate the vibrating plate, and closely attached to the front side of the vibrating plate along a node line of the vibrating plate. A sheet-shaped elastic body, an anisotropic conductive rubber sheet arranged in close contact with one electrode of the piezoelectric element and a node line located outside the electrode on the back side of the diaphragm, and the anisotropic conductive rubber sheet. One side of the conductive rubber sheet, which has an insulative base plate that covers the vibrating plate with its piezoelectric element bonding side and an inner diameter into which the vibrating plate and the base plate fit, and the upper and lower open ends are A case member that is bent over the peripheral portion of the elastic body and the base plate and elastically supports the diaphragm between the elastic body and the anisotropic conductive rubber sheet; and one of the diaphragm and the piezoelectric element The electrode is an anisotropic conductive rubber sheet Through which the terminals are provided respectively on the base plate, and the vibrating plate is such that the bonding portion of the piezoelectric element projects to the outside of the case member, and the thickness of this projecting portion is changed to adjust the frequency. An ultrasonic transducer characterized by doing so.