JP3763531B2 - Piezoacoustic transducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric acoustic transducer used in various sound reporting devices, telephones, and the like.
[0002]
[Prior art]
As this type of piezoelectric acoustic transducer, a surface mount type is known. Surface mount type piezoelectric acoustic transducers are known, for example, from Japanese Unexamined Patent Publication No. 2000-175296 and Japanese Utility Model Laid-Open No. 05-75798. The surface-mount type piezoelectric acoustic transducers described in these known documents employ a structure in which a power supply terminal is embedded in a resin case supporting the periphery of the piezoelectric acoustic transducer by insert molding. According to this insert molding, the product can be miniaturized and a high terminal fixing force can be secured even when the product is miniaturized.
[0003]
[Problems to be solved by the invention]
However, in order to perform insert molding efficiently, it becomes necessary to form a hoop in the terminal part for conveyance to the molding machine, new equipment for taking out the molded product after molding, and a dedicated molding machine. There was a problem that the equipment cost increased.
[0004]
Moreover, since it is a resin molding process, production efficiency that satisfies industrial mass production could not be achieved. Further, there is a problem that the adaptability to the product shape change is low.
[0005]
The various problems described above eventually rebound to the product cost, and it has been difficult to provide a piezoelectric acoustic transducer with low cost and high reliability.
[0006]
An object of the present invention is to provide a piezoelectric acoustic transducer having a low cost and high reliability.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described problems, a piezoelectric acoustic transducer according to the present invention includes a case, a piezoelectric acoustic transducer, and a pair of terminal members. The case is made of a thermoplastic synthetic resin material and has a protrusion on the inner bottom surface. The periphery of the piezoelectric acoustic transducer is supported by a case.
[0008]
Each of the pair of terminal members constitutes a feeding path for the piezoelectric acoustic transducer and is made of a metal plate material. Each of the pair of terminal members has a recess formed by a notch at one end edge, and is disposed on the inner bottom surface on both sides of the protrusion so that the protrusion is positioned in the recess. It is fixed to the case by welding.
[0009]
As described above, the periphery of the piezoelectric acoustic transducer is supported by the case, and each of the pair of terminal members constitutes a power feeding path to the piezoelectric acoustic transducer, so that the piezoelectric acoustic transducer is formed using the pair of terminal members. An electrical signal can be supplied to the conversion element and excited.
[0010]
Since each of the pair of terminal members is made of a metal plate and is disposed on the inner bottom surface of the case, the internal space of the case can be set to a thickness that takes into account the plate thickness of the terminal member, and can be thinned. .
[0011]
The case is made of a thermoplastic synthetic resin material and has a protrusion on the inner bottom surface. Each of the pair of terminal members has a notch at one end edge, and is disposed on the inner bottom surface on both sides of the protrusion so that the protrusion is positioned in the recess, and is fixed to the case by welding the protrusion. Has been. According to such a structure, the pair of terminal members can be fixed to the case by melting the protrusion and subsequent welding treatment. Since the protrusion is a part of the case and is made of a thermoplastic synthetic resin material, the protrusion can be melted and welded to the pair of terminal members by simply pressing a heating means such as a thermal iron.
[0012]
This eliminates the need for hooping of the terminal portion necessary for the insert molding process, new equipment for taking out the molded product after molding, and a dedicated molding machine. In addition, production efficiency is improved and adaptability to product shape changes is extremely high. Therefore, according to the present invention, a highly reliable piezoelectric acoustic transducer can be obtained at low cost.
[0013]
In a specific aspect, the pair of terminal members includes a contact portion and a terminal portion. The contact portion has the recess, and the terminal portion is narrower than the contact portion and continues to the contact portion. The case has two openings on the side wall surface. In each of the pair of terminal members, the terminal portion is led to the outside of the case through the opening. According to this structure, it is possible to obtain a surface mount type piezoelectric acoustic transducer in which the terminal portions of the pair of terminal members are faced to the outside.
[0014]
As a preferable aspect in this case, the case has a cave portion into which the end edge of the contact portion located at the connection position with the terminal portion is inserted. The cave has an inclined inner surface that is inclined downward toward the outside of the case. According to such a structure, the terminal portions of the pair of terminal members can be pressed using the inclined surfaces of the cave portions, so that the fixing force for the pair of terminal members can be increased and the reliability can be improved.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
1 is a front cross-sectional view of an acoustic transducer according to the present invention, FIG. 2 is a plan view of the piezoelectric sound shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. The illustrated piezoelectric acoustic transducer includes a case 1, a piezoelectric acoustic transducer 2, and a pair of terminal members 3 and 4. A lid 5 having an alarm hole 51 is attached to the upper opening of the case 1.
[0016]
The case 1 is made of a thermoplastic synthetic resin material and has a protrusion 11 on the inner bottom surface 12. 4 is a front sectional view of the case, and FIG. 5 is a plan view of the case 1 shown in FIG. The illustrated case 1 has two openings 14, 15 on the side wall surface 13, an upper surface facing the inner bottom surface 12, and a ring-shaped step surface 18 at a portion close to the inner bottom surface 12. The step surface 18 is divided by openings 14 and 15 provided in the side wall surface 13.
[0017]
Further, in the embodiment, the case 1 has the cave portions 16 on both sides of the openings 14 and 15. The cave portion 16 has an inclined inner surface 17 that is inclined downward toward the outside of the case 1.
[0018]
The periphery of the piezoelectric acoustic transducer 2 is supported by the case 1. The piezoelectric acoustic transducer 2 has a structure in which a disk-shaped piezoelectric vibrator 22 having a diameter smaller than that of the metal diaphragm 21 is bonded to one surface of a disk-shaped metal diaphragm 21. The piezoelectric acoustic transducer 2 is built in the case 1 by placing the periphery of the metal diaphragm 21 on the step surface 18 and pressing it from above with the lid 5. The piezoelectric acoustic transducer 2 is supported at the periphery so that the piezoelectric vibrator 22 faces the inner bottom surface 12 of the case 1.
[0019]
Each of the terminal members 3 and 4 constitutes a feeding path for the piezoelectric acoustic transducer 2 and is made of a metal plate material. Each of the terminal members 3, 4 has a recess 31, 41 with a notch at one end edge, and is disposed on the inner bottom surface 12 on both sides of the protrusion 11 so that the protrusion 11 is positioned in the recess 31, 41. And it is being fixed to case 1 by welding 10 of projection 11. In the illustrated embodiment, the recesses 31 and 41 constitute a triangular space, but may be another polygonal shape such as a quadrangular shape, or a spatial shape such as an arc or an elliptical shape.
[0020]
In each of the terminal members 3 and 4, the terminal portions 33 and 43 are led to the outside of the case 1 through the openings 14 and 15. In the embodiment, the terminal member 3 includes a contact portion 32 and a terminal portion 33. The contact portion 32 has a recess 31, and the terminal portion 33 is narrower than the contact portion 32 and continues to the contact portion 32. The terminal member 4 also includes a contact portion 42 and a terminal portion 43. The contact part 42 has a recess 41, and the terminal part 43 is narrower than the contact part 42 and continues to the contact part 42.
[0021]
Further, the terminal members 3 and 4 have contact pieces 34 and 44 cut and raised. The contact pieces 34 and 44 are in spring contact with the electrodes of the piezoelectric acoustic transducer 2. An electrode arrangement structure for contacting the contact pieces 34 and 44 is well known.
[0022]
As described above, the periphery of the piezoelectric acoustic conversion element 2 is supported by the case 1, and each of the terminal members 3 and 4 constitutes a feeding path for the piezoelectric acoustic conversion element 2. It is possible to supply an electric signal to the piezoelectric acoustic transducer 2 and excite it.
[0023]
Since each of the terminal members 3 and 4 is made of a metal plate and is disposed on the inner bottom surface 12 of the case 1, the internal space of the case 1 is set to a thickness considering the plate thickness of the terminal members 3 and 4. It is possible to reduce the thickness.
[0024]
The case 1 is made of a thermoplastic synthetic resin material and has a protrusion 11 on the inner bottom surface 12. Each of the terminal members 3, 4 has recesses 31, 41 with notches at one end edge, and the protrusions 11 are positioned inside the recesses 31, 41 so that the protrusions 11 are located on the inner bottom surfaces 12 on both sides of the protrusions 11. Arranged and fixed to the case 1 by welding 10 of the protrusions 11. According to such a structure, the terminal members 3 and 4 can be fixed to the case 1 by melting the protrusions 11 and subsequent welding 10 treatment. Since the protrusion 11 is a part of the case 1 and is made of a thermoplastic synthetic resin material, the protrusion 11 is melted by a simple operation of simply pressing a heating means such as a thermal iron or an ultrasonic probe, and a pair of terminal members. 3 and 4 can be welded 10.
[0025]
6-9 is a figure which shows the terminal member incorporating process in the piezoelectric acoustic transducer shown in FIGS. 1-3. First, as shown in FIGS. 6 and 7, the terminal members 3 and 4 are arranged on the inner bottom surfaces 12 on both sides of the protrusion 11 so that the protrusion 11 is positioned inside the recesses 31 and 41.
[0026]
Next, as shown in FIGS. 8 and 9, a heating means such as a thermal iron or an ultrasonic probe is pressed against the tip surface of the protrusion 11. As a result, the protrusion 11 is melted at the tip thereof, and the melted resin flows out and adheres onto the terminal members 3 and 4. Since the protrusion 11 is a part of the case 1 and is made of a thermoplastic synthetic resin material, such a welding 10 processing operation is possible.
[0027]
As described above, since the terminal members 3 and 4 can be fixed to the case 1 by melting the protrusion 11 and the subsequent welding 10 process, the hoop of the terminal portion that was conventionally necessary in the insert molding process. New equipment for taking out the molded product after conversion and molding, and a dedicated molding machine are completely unnecessary. In addition, production efficiency is improved and adaptability to product shape changes is extremely high. Therefore, according to the present invention, a highly reliable piezoelectric acoustic transducer can be obtained at low cost.
[0028]
In the embodiment, the terminal member 3 includes a contact portion 32 and a terminal portion 33. The contact portion 32 has a recess 31, and the terminal portion 33 is narrower than the contact portion 32 and continues to the contact portion 32. The terminal member 4 also includes a contact portion 42 and a terminal portion 43. The contact part 42 has a recess 41, and the terminal part 43 is narrower than the contact part 42 and continues to the contact part 42.
[0029]
On the premise of the terminal member structure described above, the case 1 has the cave portions 16 on both sides of the openings 14 and 15 for inserting the edges of the contact portions 32 and 42 that are connected to the terminal portions 33 and 43. The cave portion 16 has an inclined inner surface 17 that is inclined downward toward the outside of the case 1. According to such a structure, since the terminal portions 33 and 43 of the pair of terminal members 3 and 4 can be pressed using the inclined surface 17 of the cave portion 16, the fixing force with respect to the terminal members 3 and 4 is increased and the reliability is improved. Can be improved.
[0030]
Further, in the embodiment, the case 1 has two openings 14 and 15 on the side wall surface 13. In each of the terminal members 3 and 4, the terminal portions 33 and 43 are led to the outside of the case 1 through the openings 14 and 15. According to this structure, it is possible to obtain a surface mount type piezoelectric acoustic transducer in which the terminal portions 33 and 43 of the terminal members 3 and 4 are attached to the outside.
[0031]
【The invention's effect】
As described above, according to the present invention, a highly reliable piezoelectric acoustic transducer can be provided at low cost.
[Brief description of the drawings]
FIG. 1 is a front sectional view of an acoustic transducer according to the present invention.
FIG. 2 is a plan view of the piezoelectric sound shown in FIG.
3 is a cross-sectional view taken along line 3-3 in FIG.
FIG. 4 is a front sectional view of the case.
5 is a plan view of the case shown in FIG. 4. FIG.
6 is a diagram showing a terminal member assembling step in the piezoelectric acoustic transducer shown in FIGS. 1 to 3; FIG.
7 is a plan view of the process shown in FIG. 6. FIG.
8 is a cross-sectional view showing a step subsequent to FIGS. 6 and 7. FIG.
9 is a plan view of the step shown in FIG. 8. FIG.
[Explanation of symbols]
1 Case 2 Piezoacoustic transducer 3, 4 Terminal member 11 Protrusion 31, 41 Recess

Claims (3)

A piezoelectric acoustic transducer including a case, a piezoelectric acoustic transducer, and a pair of terminal members,
The case is made of a thermoplastic synthetic resin material, and has a protrusion on the inner bottom surface.
The piezoelectric acoustic transducer has a periphery supported by the case,
Each of the pair of terminal members constitutes a feeding path for the piezoelectric acoustic transducer, is made of a metal plate material, has a recess formed by a notch at one end edge, and the protrusion is located in the recess. In this manner, the piezoelectric acoustic transducer is disposed on the inner bottom surface on both sides of the protrusion and is fixed to the case by welding of the protrusion. The piezoelectric acoustic transducer according to claim 1,
The pair of terminal members includes a contact portion and a terminal portion,
The contact portion has the recess,
The terminal portion is narrower than the contact portion and is continuous with the contact portion,
The case has two openings on the side wall surface,
Each of the pair of terminal members is a piezoelectric acoustic transducer in which the terminal portion is guided to the outside of the case through the opening. The piezoelectric acoustic transducer according to claim 2,
The case has a cave portion for inserting an end edge of the contact portion at a position connected to the terminal portion,
The cave portion is a piezoelectric acoustic transducer having an inclined inner surface that is inclined downward toward the outside of the case.

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