JP2001258096A - Manufacturing method for piezoelectric diaphragm for loudspeaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a ceramics layer from cracking in the case of forming a center hole to a piezoelectric diaphragm. SOLUTION: A through-hole 32 is formed at the center of a metallic thin plate 30 formed to be a prescribed shape, ceramics layers 34, 36 are adhered to both sides of the metallic thin plate 30, a punch P' whose outer diameter is equal to or smaller than an inner diameter of the through-hole 32 is positioned with respect to the through-hole 32 on the surface of the one ceramics layers 34 adhered to the metal-made thin plate 30, the punch P' is penetrated from the surface of the ceramic layer 34 to the other ceramic layer 36 via the through-hole 32 to form a center hole 38, and a center support member 18 is penetrated and fixed at the center hole 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a piezoelectric vibrator for a speaker.

[0002]

2. Description of the Related Art Conventionally, a piezoelectric vibrating plate has been supported at the center thereof, and attached to the acoustic vibrating plate to transmit the vibration of the piezoelectric vibrating plate to the acoustic vibrating plate and to transmit the vibration from the acoustic vibrating plate to the surrounding air. 2. Description of the Related Art A speaker using a piezoelectric vibrator that transmits and emits a sound is known. In a speaker using such a piezoelectric vibrator, a center hole must be formed in the center of the piezoelectric diaphragm in order to support the piezoelectric diaphragm at the center with respect to the acoustic diaphragm.

[0003]

Conventionally, the center hole is formed by attaching a ceramic layer having no hole at the center to both sides of a metal plate having no hole at the center, and then using a punch. A central hole penetrating the three layers is formed. This method has an advantage that the relative positioning of the holes in each layer can be completely completed, as compared with the case where the holes are formed in the metal plate and the ceramic layer in advance and then attached. However, when the punch penetrates the metal plate, the central region of the metal plate swells and deforms in the direction of advance of the punch, causing a problem that the central region of the lower ceramic layer breaks larger than desired dimensions. Furthermore, if the method of fixing the piezoelectric vibrating plate is incomplete or the accuracy of the mold for fixing the piezoelectric vibrating plate is poor, not only the central region of the metal plate when the punch penetrates the metal plate, but also the entire metal plate Deformation may cause cracks to spread throughout the ceramic layer.

An object of the present invention is to solve such problems of the prior art, and a method of manufacturing a piezoelectric vibrating body for a speaker in which a ceramic layer is prevented from cracking when a center hole is formed in a piezoelectric vibrating plate. It is intended to provide. Still another object of the present invention is to form the center hole of the piezoelectric diaphragm with high accuracy.

[0005]

According to the present invention, a through hole is formed in the center of a thin metal plate molded into a predetermined shape, and a ceramic layer is attached to both surfaces of the thin metal plate. A punch having an outer diameter of is positioned with respect to the through hole on the surface of one ceramic layer attached to the metal thin plate, and from the surface of the one ceramic layer to the other ceramic layer through the through hole. A gist of the present invention is a method for manufacturing a piezoelectric vibrating body for a speaker, comprising forming a center hole by penetrating a punch, and inserting and fixing a center support member through the center hole.

[0006]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, a piezoelectric vibrating body 10 includes a circular metal plate 14 and a metal plate 14 made of a thin metal plate such as aluminum, stainless steel, and brass.
The piezoelectric vibrating plate 12 includes an annular rubber damper 20 provided along the periphery of one ceramic layer 16 attached to both surfaces of the ceramic layer 16 with an appropriate adhesive. The ceramic layer 16 is formed over substantially the entire surface of both surfaces of the metal plate 14. Piezoelectric diaphragm 12
Has a rod 18a and a bracket 1 at its center.
It is attached to one side surface of the acoustic diaphragm 22 by a center support member 18 made of 8c. More specifically, the piezoelectric diaphragm 1
A center hole 12a is formed at the center of the second member 2. A rod 18a at the tip of the center support member 18 is inserted into the center hole 12a, and the piezoelectric vibration plate 12 is screwed to the center support member 18 by a nut 18b. Thus, the piezoelectric vibrator 10 is formed. The piezoelectric vibrating body 10 is bonded to one surface of the acoustic vibration plate 22 with a suitable adhesive at a bracket 18c formed in a divergent shape on the opposite side of the rod 18a of the center support member 18. The acoustic diaphragm 22 includes the piezoelectric vibrator 1
Materials suitable for efficiently exciting air and emitting sound by vibration transmitted from 0, for example, plastic plate material, synthetic resin as a binder, aramid fiber, carbon fiber,
It can be formed of a plate made of a composite material using glass fiber as a reinforcing fiber, a plaster board, or a plate made of styrene foam.

Next, a method of manufacturing a piezoelectric vibrator according to the embodiment of the present invention will be described with reference to FIGS. First,
In FIG. 2, a circular material 30 for forming the metal plate 14 is formed from a plate material or a strip W having the same material and thickness as the metal plate 14 by punching with a press die P. At this time, a through hole 32 is formed at the center of the circular material 30 by the press die P at the same time.

Next, as shown in FIGS.
A circular ceramic layer 34, 36 having a diameter substantially equal to or slightly smaller than that of the circular material 30 is attached to both surfaces of the “0” with an appropriate adhesive. The ceramic layers 34, 36
It can be formed of a ferroelectric ceramic material such as barium titanate or lead zirconate titanate. Then
A punch P ′ having an outer diameter equal to or slightly smaller than the inner diameter of the through-hole 32 of the circular material 30 is formed in the through-hole 32 on the surface of one ceramic layer (the upper ceramic layer 34 in FIG. 5) attached to the circular material 30. The circular material 30 and the punch P 'are relatively positioned such that the center of the through hole 32 and the central axis of the punch P' coincide. Then, the punch P ′ is moved closer to the upper ceramic layer 36 as shown by an arrow in FIG. 5 so that the surface of the one ceramic layer 34 (upper ceramic layer 34) passes through the through-hole 32 to the other ceramic layer. The center hole 38 (the center hole 12a in the embodiment of FIG. 1) is formed by penetrating the punch P 'into the (lower ceramic layer 36). Finally, the center support member 18 (see FIG. 1) is inserted into and fixed to the center hole 38 (12a), and the piezoelectric vibrating body 10 is formed.

According to the present embodiment, since the through hole 32 is formed in advance in the center of the circular material 30 constituting the metal plate 14, when the center hole 38 is formed by the punch P ', the circular material 30 is used. No substantial force is applied to 30 from the punch P '. Therefore, the circular material 30 is not deformed when the center hole 38 is formed, and the ceramic layers 34 and 36, particularly the lower ceramic layer (that is, the metal circular material 30 with respect to the progress of the punch) due to the deformation of the circular material 30 are not deformed. The next ceramic layer) is prevented from cracking.

Having described the preferred embodiment of the invention,
It is obvious to those skilled in the art that the present invention is not limited to this, and various changes and modifications are possible. For example,
In FIG. 5, the punch P 'is illustrated as a cylindrical punch, but the punch P' is not limited to a simple cylindrical punch. For example, a spherical recess may be formed on the tip end surface of the punch P 'and a cutting blade may be provided along the peripheral edge. Alternatively, the punch P 'may be formed in a hollow cylindrical shape, and a cutting blade may be provided along the peripheral edge of the opening facing the piezoelectric vibration plate. Thus, by providing the cutting edge at the tip of the punch P ', it is possible to form the inner circumference of the ceramic layer 36 along the center hole 38 with high precision. At this time, according to the present embodiment, the through hole 32 is formed in the center of the metal circular material 30 in advance, so that the wear of the cutting blade can be removed or reduced.

Further, the punch P 'is not a simple cylindrical punch, but can be provided with a taper in a tip region which engages with the piezoelectric vibrating plate. That is, the outer diameter of the tip of the punch P 'is made smaller than the inner diameter of the through hole 32, and the taper is provided in the tip region of the punch P' so as to gradually approach the inner diameter of the through hole 32 behind the punch P '. Can be. By providing the taper, when the punch P 'is engaged with the through hole 32, the through hole 32 acts as a guide, and the punch P' and the piezoelectric vibration plate are automatically aligned. This facilitates the positioning of the punch P 'and the piezoelectric vibration plate in the step of forming the center hole 38. In this embodiment, the relative positioning between the through hole 32 and the punch P 'does not need to completely coincide with the center axis of the through hole 32 and the center axis of the punch P'. The term “positioning” according to claim 1 includes such examples.

Further, the circular material 30 made of metal is provided with through holes 32.
, The tip of the punch P ′ can be formed into a needle-like point, thereby generating a concentrated stress in a smaller area and applying a very small force to the center hole 3.
8 can be easily formed.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a speaker using a piezoelectric vibrator.

FIG. 2 is a schematic view showing one step of a method for manufacturing a piezoelectric vibrator according to a preferred embodiment of the present invention.

FIG. 3 is a schematic view showing one step of a method for manufacturing a piezoelectric vibrator according to an embodiment of the present invention.

FIG. 4 is a schematic view showing one step of a method for manufacturing a piezoelectric vibrator according to an embodiment of the present invention.

FIG. 5 is a schematic view showing one step of a method for manufacturing a piezoelectric vibrator according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Piezoelectric vibration body 12 ... Piezoelectric vibration plate 14 ... Metal plate 16 ... Ceramic layer 18 ... Center support member 20 ... Damper 22 ... Acoustic vibration plate 30 ... Circular material 32 ... Through hole 34 ... Ceramic layer 36 ... Ceramic layer

Claims (1)

[Claims] 1. A through-hole is formed in a central portion of a metal thin plate molded into a predetermined shape, ceramic layers are stuck on both surfaces of the metal thin plate, and a punch having an outer diameter equal to or less than the inner diameter of the through-hole is provided. Positioning the surface of the one ceramic layer attached to the metal thin plate with respect to the through hole, and passing the punch from the surface of the one ceramic layer through the through hole to the other ceramic layer to form a center hole. A method for manufacturing a piezoelectric vibrating body for a speaker, comprising: forming and fixing a center support member through the center hole.