JPH0641299U - Piezoelectric transducer - Google Patents

Abstract

(57) [Abstract] [Purpose] Prevents the sealant from flowing out and adhering to the lead wire lead-out part. [Structure] In a case 1, an outer wall portion 10 forms an internal space 12 inside, and a stepped ring-shaped end face 13 is provided around the internal space 12. The protruding portion 11 is provided so as to protrude from the outer wall portion 10 and has a recessed groove 14 which is continuous with the end face 13. The piezoelectric vibrating plate 2 has its periphery fixed on the end face with an adhesive 3 and a cavity 121 formed by the internal space 12 on the adhesive face side,
The lead wires 4 and 5 are led out from the cavity 121 side through the concave groove 14.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a piezoelectric transducer, and more particularly, to improvement of a piezoelectric transducer used in telephones, intercoms and the like.

[0002]

[Prior art]

 As a prior art document of this type of piezoelectric transducer, Japanese Utility Model Laid-Open No. Sho 63-68298 can be cited. In the conventional piezoelectric transducer, the case has a ring-shaped inner space and a ring-shaped end face around the inner space. The periphery of the piezoelectric vibrating plate is fixed on the end face of the case by an adhesive, a cavity is formed on the side of the bonding surface by the internal space, and the lead wire is led out from the cavity side. The lead wire is led out to the outside of the case through a notch provided in a part of the case. The notch is sealed with, for example, a silicone resin in order to keep the cavity airtight.

[0003]

[Problems to be solved by the device]

 As described above, in the conventional piezoelectric transducer, the lead wire for feeding is led out to the outside of the case through the notch provided in part of the case, so that the sealing agent that keeps the airtightness of the cavity is cut off. Through the notch, it could flow out to the outer peripheral surface of the case, resulting in a defective product.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems and to provide a piezoelectric transducer capable of preventing the sealing agent from flowing out and adhering to the lead wire lead portion.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is a piezoelectric transducer including a case and a piezoelectric vibrating plate, wherein the case has an outer wall portion and a protrusion, and the outer wall portion has an internal space inside. And has a stepped ring-shaped end face around the inner space, the protrusion has a concave groove protruding from the outer wall, and connected to the end face. Has a periphery fixed to the end face with an adhesive and forming a cavity by the internal space on the adhesion surface side, and a lead wire is led out from the cavity side through the concave groove.

[0006]

[Action]

 The case has an outer wall that forms an internal space inside and a stepped ring-shaped end face around the internal space.The periphery of the piezoelectric vibrating plate is fixed on the end face by an adhesive and Since the cavity is formed by the internal space, a piezoelectric transducer that performs electro-acoustic conversion by the piezoelectric effect of the piezoelectric element can be obtained.

The case has a protrusion protruding from the outer wall and has a concave groove connected to the ring-shaped end face. Since the lead wire is led out from the cavity side through the concave groove, the lead wire lead-out portion Is enlarged, the sealant is less likely to adhere to the outer peripheral surface of the case, and the probability of appearance failure is reduced. In addition, the pressing member can be inserted into the groove for more reliable sealing.

[0008]

【Example】

 1 is an exploded perspective view of a piezoelectric converter according to the present invention, and FIG. 2 is a sectional view of the piezoelectric converter shown in FIG. Reference numeral 1 is a case, 2 is a piezoelectric diaphragm, 3 is an adhesive, and 4 and 5 are lead wires. The case 1 is made of a suitable material such as synthetic resin and has an outer wall portion 10 and a protrusion portion 11. The outer wall portion 10 has an inner space 12 formed therein, and also has a stepped ring-shaped end face 13 around the inner space 12. The protruding portion 11 is provided so as to protrude from the outer wall portion 10, and has a recessed groove 14 that is continuous with the end surface 13.

The piezoelectric vibrating plate 2 has its periphery fixed on the end face 13 with the adhesive 3 and forms a cavity 121 by the inner space 12 on the adhesive face side, and the lead wires 4 and 5 pass through the concave groove 14 from the cavity 121 side. It has been derived. The piezoelectric diaphragm 2 has a piezoelectric element 21 and a diaphragm 22. The piezoelectric element 21 is attached to the one surface 221 side of the diaphragm 22. The piezoelectric element 21 has electrodes 212 and 213 on opposite sides of the piezoelectric ceramic 211. The diaphragm 22 is usually composed of a thin metal plate such as an iron-nickel alloy. The lead wires 4 and 5 are connected to the electrodes 212 and 213 of the piezoelectric element 21.

As described above, the case 1 has the outer wall portion 10 forming the internal space 12 therein, and also has the stepped ring-shaped end face 13 around the internal space 12, and the piezoelectric vibration plate The peripheral portion of the piezoelectric element 2 is fixed on the end face 13 by the adhesive 3 and the cavity 121 formed by the internal space 12 is formed on the adhesive surface side. Is obtained.

The case 1 is provided with a protruding portion 11 protruding from the outer wall portion 10 and has a recessed groove 14 continuous with the ring-shaped end face 13. The lead wires 4 and 5 pass through the recessed groove 14 from the cavity 121 side. Since the lead wire lead-out portion is enlarged, the sealant is less likely to adhere to the outer peripheral surface of the case, and the probability of appearance failure is reduced.

The recessed groove 14 has a wide portion 141 at an intermediate portion, and the pressing member 6 is inserted into the wide portion 141. By inserting the pressing member 6 made of silicon rubber or the like into the wide portion 141, the lead wires 4 and 5 can be pressed and can be sealed.

Further, the case 1 has a hole 15, the hole 15 is provided in the outer wall portion 10 forming the inner space 12, and the piezoelectric vibrating plate 2 has a cavity 121 including the hole 15 formed therein. Peripherally supported on 1. Reference numeral 7 is an acoustic resistance sheet made of mesh cloth, and the acoustic resistance sheet 7 is adhered to the outer wall portion 10 with an adhesive 8 to close the hole 15. With such a structure, the acoustic resistance sheet 7 and the holes 15 can provide appropriate acoustic resistance damping, flatten the frequency characteristic, and improve the frequency characteristic.

Further, in the case 1, the outer wall portion 10 forming the inner space 12 has a recessed portion 16 around the hole 15, and the acoustic resistance sheet 7 is covered with the adhesive 5 filled in the recessed portion 16 to form the outer wall portion 10. Is glued to. With such a structure, the concave portion 16 functions as a reservoir for the adhesive 8 and can absorb a variation in the filling amount of the adhesive 8. Further, even when the adhesive 8 is set to a relatively large amount that is easy to work, the amount overflowing from the recess is reduced and the same result as when a very small amount of adhesive is applied can be obtained. You can For this reason, it is possible to prevent defective adhesion due to the outflow of the adhesive and excessive adhesion due to the outflow, and it is possible to prevent braking failure due to excessive penetration of the adhesive 8 into the acoustic resistance sheet 7 made of mesh cloth.

FIG. 3 is an exploded perspective view showing another embodiment of the piezoelectric converter according to the present invention, and FIG. 4 is a sectional view thereof.

The case 1 is provided with three or more protrusions 17 on the end surface 13 at intervals, and the piezoelectric diaphragm 2 has the diaphragm 22 arranged on the protrusion 17. With such a structure, three or more fulcrums necessary for stable support of the piezoelectric diaphragm 2 are secured. Therefore, it is possible to stably support the piezoelectric diaphragm 2 in a substantially horizontal state without tilting it and to secure a predetermined frequency characteristic. The protrusions 17 have a triangular shape, a quadrangular shape, another polygonal shape, or a semicylindrical shape, and three or more protrusions 17 are provided.

[0017]

[Effect of device]

 As described above, according to the present invention, the following effects can be obtained. (A) In the case, the outer wall part forms an internal space inside and has a stepped ring-shaped end face around the internal space. The periphery of the piezoelectric diaphragm is fixed on the end face by an adhesive. Since the cavity is formed by the internal space on the adhesive surface side, a piezoelectric transducer that performs electro-acoustic conversion by the piezoelectric effect of the piezoelectric element can be obtained. (B) The case has a protrusion protruding from the outer wall and has a groove extending to the ring-shaped end face. The lead wire is led out from the cavity side through the groove. As a result, the sealant is less likely to adhere to the outer peripheral surface of the case, the probability of occurrence of poor appearance is reduced, and sealing by the pressing member is possible.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a piezoelectric transducer according to the present invention.

FIG. 2 is a sectional view of the piezoelectric converter shown in FIG.

FIG. 3 is an exploded perspective view showing another embodiment of the piezoelectric converter according to the present invention.

FIG. 4 is a cross-sectional view of the piezoelectric converter shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 10 Outer wall part 11 Projection part 12 Internal space 13 End surface 14 Recessed groove 2 Piezoelectric diaphragm

Claims (4)

[Scope of utility model registration request] 1. A piezoelectric transducer including a case and a piezoelectric vibrating plate, wherein the case has an outer wall portion and a protrusion portion, the outer wall portion forming an internal space therein, and It has a stepped ring-shaped end face around the inner space, and the protrusion has a recessed groove that is provided so as to project from the outer wall and is continuous with the end face.The periphery of the piezoelectric vibrating plate is on the end face. Is fixed with an adhesive to form a cavity with the internal space on the adhesive surface side,
A piezoelectric transducer in which a lead wire is led out from the cavity side through the concave groove. 2. The piezoelectric transducer according to claim 1, further comprising a sealing member, wherein the sealing member is inserted into the groove and holds the lead wire. 3. The case according to claim 1, wherein the case has three or more protrusions spaced apart from each other on the end face, and the periphery of the piezoelectric vibrating plate is received by the protrusions. Piezoelectric transducer. 4. The case has a hole provided in the outer wall portion, the hole is covered with an acoustic resistance sheet, and the wall portion has a recessed portion around the hole. The plate is supported so that a cavity including the hole is formed in the internal space, and the acoustic resistance sheet is adhered to the wall portion by an adhesive agent filled in the recess. 2. The piezoelectric converter according to 2 or 3.