JPS6366480B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a small speaker, particularly to automatic assembly.

Speakers have high sound pressure, good frequency characteristics over a wide band, low power consumption, low processing costs, and easy assembly. It is required to be small and thin.

In particular, in the case of wristwatches, it is necessary to make them smaller and thinner, and at the same time, to achieve high sound pressure and good frequency characteristics with low power consumption, as well as environmental resistance such as heat resistance, cold resistance, moisture resistance, vibration resistance, and equilibrium resistance. Various structural efforts have been made to improve performance, sweat and waterproof properties, etc., but even if a prototype product with good performance is produced, it is often expensive and problematic. Ta.

FIG. 1 is a partial cross-sectional view showing an example of the structure of a conventional small speaker.

A magnet 2, an upper yoke 3, and a lower yoke 4 are incorporated into the frame 1. A voice coil 6 is bonded to the diaphragm 5, and its terminal is connected to a terminal electrode sheet 7 and soldered. Frame 1 and diaphragm 5 are fixed with adhesive 8.

However, when applying the adhesive 8, since the adhesive part is long on the outer periphery of the diaphragm 5, it is difficult to supply and apply the adhesive 8 uniformly.
The adhesive surface became uneven, causing variations in frequency characteristics, and in some cases, the adhesive surface was broken, resulting in defects in waterproofness. Furthermore, if the bonded portion is long, assembly becomes difficult, resulting in a major problem in terms of cost.

This speaker is designed to be installed just inside the perforated case of the watch, and the diaphragm 5
is exposed to the outside air. In addition, in case strong pressure such as water pressure is applied, the frame 1 is placed immediately inside the diaphragm 5 to prevent the diaphragm 5 from being bent greatly.

Although the structure for waterproofing the inside of the watch body is not shown, it is provided around the speaker, and waterproofing is performed using a known structure to prevent water from entering the inside of the speaker and the watch body from the outside. .

However, it takes time to cure the adhesive, requires extra cost for positioning during automatic assembly, and tends to result in products with poor waterproof properties.

The present invention aims to reduce the cost of automatic assembly by using a vibrating membrane as a belt for positioning.

FIG. 2 is a schematic diagram of a diaphragm sheet showing the process of manufacturing a small speaker according to an embodiment of the present invention.

For stationery, thickness is 100 (80 to 120 is good)
A thermoplastic plastic sheet (for example, an engineering plastic of polycarbonate or allyl ester resin (for example, one made of U-polymer (trademark) is preferable) of about μm size is supplied, and thermoformed as the diaphragm 25 and subsequent steps. A pilot hole 20 is drilled to serve as a positioning reference. The cross section here is as shown in FIG.

At the station rotor, an adhesive 28 such as UV adhesive (ultraviolet curable adhesive) is transferred into a ring shape in order to fix the diaphragm 25 and the voice coil 26 together. Please refer to Figure 4 for the cross-sectional view.

The voice coil 26, which has been pre-wound into a ring and is fed, is automatically supplied to the station 2, and then ultraviolet rays are irradiated from the upper surface or the lower surface through the diaphragm 25 at the station 2, and the adhesive 28 is cured. . Please refer to Figure 5 for the cross section here.

The sheet material is then inverted and sent to the station.

At the station, a magnetic circuit consisting of a frame 21, a magnet 22, an upper yoke 23, a lower yoke 24, an electrode sheet 27, etc., assembled in advance on a separate automatic assembly line, is sorted and automatically supplied.
They are positioned on the lower surface side of the diaphragm 25 and then overlapped. Next, the frame 21 and the diaphragm 25 are fixed to the station along the outer periphery by ultrasonic welding. In this ultrasonic welding method, the contact surfaces of the diaphragm 25 and the frame 21 are melted and joined by frictional heat generated by ultrasonic vibration, and the bonding force is extremely strong. In addition, when performing ultrasonic welding, a 0.75 mm wide ring-shaped welding tool is used at the tip of the horn, and a certain pressure is applied to transmit ultrasonic vibrations.
By using this welding tool with high precision in terms of ring width and height, and by accurately adjusting the pressure applied to the welded object, the width of the ultrasonic welded portion 29 was made uniform. The outer diameter is 20φ as a condition for ultrasonic welding.
In the case of a small speaker of about mm, the pressure is 40 to 60
Pound, swing width 30~60μm, welding time 0.5~0.8
If the hold time is 0.8 to 1.2 seconds,
The quality was relatively good. However, the output of the ultrasonic welding device was 450W and the frequency was 20KHz.
The cross section here is as shown in FIG.

Also, when welding, the welded part of the frame 21,
It is effective to provide a protrusion with a height of 0.2 to 0.3 mm in advance and crush it with the welding tool 30. In particular, as shown in FIG. 9, a protrusion 32 is raised from inside the annular groove 31,
If the amount of protrusion and the amount of recess are made almost equal, the finishing accuracy will be very good.

At the station, the speaker is separated from the sheet material 25. Thereafter, the terminal of the voice coil 26 is connected to the electrode sheet 27, and the small speaker is completed.

According to this example, the frequency characteristics are more stable than when adhesive was used for bonding.
Products that have no problems with waterproofing are now being manufactured. Also, the number of assembly steps during manufacturing is
Compared to the adhesive method, the cost can be significantly reduced to 1/3 to 1/5, and since the vibrating membrane is used as a belt, the cost of the jig is also extremely advantageous.

As described above, the present invention has the effect of significantly reducing the cost of the jig.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an example of the structure of a small speaker, and FIG. 2 is a process diagram showing an outline of the process order on a plastic sheet. 3, 4, 5, and 6 are sectional views corresponding to steps A, B, C, and E in FIG. 2, and FIG. 7 is a sectional view showing the finished product. Eighth,
FIG. 9 is a partial sectional view of the processing tool. 1, 21... Frame, 2, 22... Magnet,
3,23...upper yoke, 4,24...lower yoke,
5, 25... Vibration plate, 6, 26... Voice coil, 7, 27... Electrode sheet, 8, 28... Adhesive, 29... Ultrasonic welding part, 20... Pilot hole.

Claims (1)

[Claims] 1 Diaphragm, frame, voice coil, yoke,
In a speaker composed of a magnet or the like, the material of the diaphragm is used as a conveying sheet, pilot holes for progressive positioning are passed through the sheet, and the sheet itself is guided by the pilot holes at each location. molding and voice coil installation,
1. A method of manufacturing a small speaker, which comprises sequentially attaching necessary members, including attaching a frame having a preset yoke magnet, etc., onto the sheet, and punching out a speaker assembly from the sheet.