JPH02182100A - Piezoelectric speaker - Google Patents

Abstract

PURPOSE:To increase mechanical strength without increasing weight and deteriorating flexibility by adhering a synthetic resin tape to one side of a lead wire and placing the adhered part to at least the start part in the part prolonged from the soldered point toward a diaphragm so as to protect the lead wire. CONSTITUTION:A synthetic resin tape 8 is adhered to a part of lead wires 7a, 7b placed in a space so as to cover the part. The left side of the synthetic resin tape 8 is adhered to the circumferential ridge of a piezoelectric body 6a and a metallic plate 6b respectively while covering electrodes 70a, 70b. On the other hand, the right side of the synthetic resin tape 8 is formed to be U-shape corresponding to bents 71a, 71b and adhered over the entire length. Then the right terminal of the synthetic resin tape 8 is inserted by a proper length between butted faces of both foamed resin plates 4, 5. Since the mechanical strength of the lead wire is increased without losing the weight and flexibility, a broken lead wire is surely prevented and the mounting workability is improved.

Description

[Detailed Description of the Invention] Lord! The present invention relates to a piezoelectric speaker in which a piezoelectric sounding body is attached to a diaphragm made of a foamed resin.

Figure 4 shows a conventional example of this type of piezoelectric speaker. In this piezoelectric speaker, a diaphragm 3 is formed by abutting two foamed resin plates 4.5 made of foamed polystyrene, foamed polyethylene, etc., facing each other, and a piezoelectric sounding body 6 is sandwiched between the foamed resin plates 4.5. It has a retained structure.

Specifically, annular grooves 4a and 5a are formed in the center of the opposing surfaces of the foamed resin plate 4.5, and the piezoelectric sounding body 6 is inserted between the protrusions 4b and 5b remaining at the center of the grooves 4a and 5a. The structure is such that it is held under pressure. In addition, in FIG. 4, grooves 4a and 5a
Only one side of is visible. The piezoelectric sounding body 6 has a piezoelectric body 6a (with a smaller diameter) on one side of a circular metal plate 6b.
For example, it is made of PZT, etc.) and is pasted concentrically.

Then, one end side of the lead wires 7a and 7b are soldered to positions near the circumferential ends of the piezoelectric body 6a and the metal plate 6b, respectively, and the electric wires 7a and 7b are soldered.
70a and 70b are formed.

The other ends of the lead wires 7a and 7b are led out through the opposing surfaces of the foamed resin plate 4.5, and are connected to an amplifier (not shown) that vibrates the piezoelectric sounding body 6 via the lead wires 7a and 7b. has been done. A U-shaped bent portion 7 is provided in the portion of the lead wires 7a, 7b located in the space formed by the grooves 4a, 5a.
1a and 71b are formed. These bent portions 71a, 71
b is provided to prevent breakage of the lead wires 7a, 7b and damage to the vibration characteristics of the piezoelectric sounding body 6 during vibration (when the piezoelectric speaker sounds).

However, in the case of the above conventional example, the lead wire 7a
, 7b do not have sufficient mechanical strength, the piezoelectric sounding element 6 and the lead wire 7 are
The vibrations (amplitudes of vibrations) of a and 7b were very large, and there was a limit to preventing wire breakage.

In order to prevent such disconnection, the wire diameters of the lead wires 7a and 7b may be increased to increase their mechanical strength, but in this case, the vibration characteristics of the piezoelectric sounding body 6 may be impaired and the sound pressure level may be reduced. It has the disadvantage of coming. Therefore, the lead wire 7a,
There is a limit to increasing the wire diameter of 7b.

Also, in the conventional example above, are the two lead wires in a non-binding relationship with each other? Since the lead wires 7a and 7b are disposed in close proximity to each other, there is a drawback in that when vibrating, the lead wires 7a and 7b vibrate into contact with each other to generate chattering vibrations, resulting in abnormal noises such as chattering noise.

In order to suppress the occurrence of such abnormal noise, the lead wires 7a, 7b
It is possible to integrate them by resin coating, but in this case, the workability of assembly becomes extremely poor, and the lead wire 7
This is not practical because it impairs the flexibility of parts a and 7b and the mechanical strength against vibration.

The present invention has been made in view of the current situation, and it is an object of the present invention to provide a piezoelectric speaker that can eliminate the above-mentioned drawbacks.

In the present invention, a piezoelectric sounding body having a piezoelectric body provided on one side of a metal plate is attached to a diaphragm made of a foamed resin, and one end of two lead wires is connected to the metal plate and the piezoelectric body. In a piezoelectric speaker that has a structure in which the lead wires are soldered to one side of each lead wire, and the other end with a U-shaped bent part formed in the middle is drawn out to the outside along the diaphragm, the lead wire is soldered to one side of the lead wire. It is characterized in that a resin tape is bonded, and the bonded portion extends from the solder point to at least the starting end of the portion along the diaphragm.

In certain cases, the lead wires are protected by the synthetic resin tape, making it possible to increase their mechanical strength without sacrificing their weight and flexibility.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view showing a piezoelectric speaker according to the present invention;
- Fig. 2 is an enlarged sectional view showing the main part, and Fig. 3 is a plan view of the main part.

It is.

The diaphragm 3, which emits sound from the front side corresponding to the upper side in the figure when vibration is applied, is formed by adhering two foamed resin plates 4.5 made of foamed polystyrene, foamed polyethylene, etc. in a facing manner. . Both foamed resin plates 4.5 have a rectangular shape, but the upper (front) foamed resin plate 4 is longer than the lower foamed resin plate 5, and a stepped portion is formed at the bonded portion of both. Ru.

A ring-shaped 1JI4 is placed in the center of the opposite surface of the foamed resin plate 4.50.
a, 5a are provided in abutting manner, and these grooves 4a
, 5a, a piezoelectric sounding body 6 is sandwiched and held between them. Specifically, a circular protrusion 4b remaining in the center of the grooves 4a and 5a,
It has a structure in which a piezoelectric sounding body 6 is attached between 5b using adhesive or the like. Therefore, the height of the protrusions 4b, 5b is slightly shorter than the depth of the grooves 4a, 5a.

The piezoelectric sounding body 6 has a structure in which a circular piezoelectric body 6a (for example, made of PZT or the like) having a smaller diameter is attached concentrically to the upper surface of a circular metal plate 6b. Note that the foamed resin plate 5 located on the lower side has a function not only as a diaphragm but also as a holder for attaching it to the frame 1 described below.

A frame 1 is provided on the peripheral edge of the diaphragm 3 to cover it. The frame 1 has a picture frame shape, and the peripheral edge of the diaphragm 30 is inserted into and connected to a groove 1a having a U-shaped cross section formed over the entire length of the inner peripheral surface. In addition, an elongated tape-shaped elastic support piece 2 is interposed around the entire circumference of the stepped portion, and the diaphragm 3 is supported by the frame I by this elastic support piece 2.

Now, there is a lead '! at a position near the circumferential edge of the piezoelectric body 6a and the metal plate 6b! Electrodes 70a and 70b are formed by soldering one ends of IA 1a and 7b, respectively. Lead wires 7a, 7
The other end side of b is drawn out to the outside through the opposing surfaces of the foamed resin plate 4.5, and connected to the piezoelectric sounding body 6 via lead wires 7a and 7b.
It is connected to an amplifier (not shown) that vibrates. U-shaped bent portions 71a, 71b are formed in the portions of the lead wires 7a, 7b located within the spaces formed by the grooves 4a, 5a. The bent portions 71a, 71b are provided to prevent breakage of the lead wires 7a, 7b and damage to the vibration characteristics of the piezoelectric sounding body 6 during vibration (when the piezoelectric speaker sounds).

Then, a synthetic resin tape 8 is placed on the parts of the lead wires 7a and 7b located in the space so as to cover them.
It is glued together. The synthetic resin tape 8 is connected to the lead wires 7a, 7.
b is mechanically reinforced, and the two are integrated to prevent vibration contact between the two and generation of chatter vibration when the piezoelectric body 6a vibrates.

The left side of the synthetic resin tape 8 is adhered to the peripheral edges of the piezoelectric body 6a and the metal plate 6b, respectively, while covering the electrodes 70a and 70b. On the other hand, the right side of the synthetic resin tee 18 is formed into a U-shape corresponding to the bent portions 71a and 71b, and is bonded over its entire length. The right end of the synthetic resin tape 8 is inserted for an appropriate length between the abutted surfaces of the re-foamed resin plates 4.5. Here, we decided to adhere the synthetic resin tape 8 in this state because these parts,
In other words, a large stress that can cause wire breakage is generated in the soldered portion, the piezoelectric body 6a, the portion located at the peripheral edge of the metal plate 6b, and the edge portion 9 at the abutting surface of the re-foamed resin plate 4.5 during vibration. 4゜By being born. That is, in order to reliably protect the dangerous parts of the lead wires 7a and 7b, it was decided to adhere the synthetic resin tape 8 to these parts. Note that the material of the synthetic resin tape 8 is preferably one that is lightweight and highly flexible.

In the above embodiment, the present invention is applied to a piezoelectric speaker in which the diaphragm is composed of two foamed resin plates facing each other, but the diaphragm is composed of one foamed resin plate, The present invention can be similarly applied to a piezoelectric speaker having a structure in which a piezoelectric sounding body is attached to one side of the piezoelectric speaker.

In the case of the present invention, which has existed for some time, it is possible to increase the mechanical strength of the lead wire without reducing its weight and flexibility, so it is possible to reliably prevent wire breakage and improve vibration characteristics, i.e. No reduction in sound pressure level occurs. Furthermore, the assembly is easy to work with, and there is no risk of generating abnormal noises such as chatter.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a piezoelectric speaker according to the present invention, FIG. 2 is an enlarged sectional view showing the main part thereof, and FIG. 3 is a plan view of the main part. FIG. 4 is a partial sectional view showing a conventional example. 3... Vibration plate, 4.5... Foamed resin plate, 6... Piezoelectric sounding body, 7a, 7b... Lead wire, 8... Synthetic resin tape. Patent applicant Murata Manufacturing Co., Ltd. Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) A piezoelectric sounding body with a piezoelectric body provided on one side of a metal plate is attached to a diaphragm made of foamed resin, and one end of two lead wires is soldered to one side of the metal plate and piezoelectric body, respectively. On the other hand, in a piezoelectric speaker having a structure in which a U-shaped bent part is formed in the middle and the other end is drawn out along the diaphragm, a synthetic resin tape is glued to one side of the lead wire, and this A piezoelectric speaker characterized in that an adhesive portion extends from a soldering point to at least a starting end of a portion along a diaphragm.