JP2000153231A - Electro-mechanical-acoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electro-mechanical-acoustic transducer having excellent reliability relating to the electro-mechanical-acoustic transducer which is used for call sounds and call vibration of portable telephones, etc., and operates to generate vibration or sounds. SOLUTION: This electro-mechanical-acoustic transducer is formed by using a yoke 4a consisting of a metal of magnetic material tinned at least on its surface, a magnet 5 adhered and fixed onto this yoke 4a and a metallic sheet laser welded to the yoke 4a. The surface of the yoke 4a is tinned to improve the strength of adhesion. The yoke 4a and suspensions 9a and 9b are laser- welded to each other, to improve the reliability of joining of electric circuits. The electro-mechanical-acoustic converter having the excellent reliability is thus obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electro-mechanical-acoustic converter which vibrates or generates sound by an electric signal used for a ringing sound or a ringing vibration of a portable telephone or the like.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIG. FIG.
FIG. 1 is a cross-sectional view of a conventional electromechanical-acoustic transducer. Referring to FIG. 1, reference numeral 1 denotes a diaphragm whose outer periphery is connected to a frame 2; Numeral 5 is a magnet adhesively bonded on the yoke 4, and numeral 6 is an upper plate adhesively bonded on the magnet 5, and a magnetic circuit 7 is formed by the yoke 4, the magnet 5 and the upper plate 6. At the same time, the other end of the voice coil 3 is fitted into the magnetic gap 8 between the yoke 4 and the upper plate 6 so as not to come into contact therewith.

[0003] Reference numerals 9a and 9b denote a pair of suspensions respectively connected to the upper and lower sides of the yoke 4, and one ends thereof are respectively connected to and supported by the frame 2. 2a is a cover.

Next, the operation of the above-described conventional electro-mechanical-acoustic converter will be described. A signal is input to the voice coil 3 from a signal source (not shown). When the frequency of this signal matches the resonance frequency of the magnetic circuit 7 including the suspensions 9a and 9b, the magnetic circuit 7 resonates and vibrates largely up and down, and the vibration is tactile.

When the resonance frequency of the vibrating portion composed of the diaphragm 1 and the voice coil 3 matches the frequency of the input signal from the signal source, the diaphragm 1 vibrates largely up and down and is sensed as sound.

The resonance frequency of the magnetic circuit 7 is 10
The electric-mechanical-acoustic transducer senses the vibration by switching the frequency of the input signal from the signal source by setting the resonance frequency of the vibrating section to about 1 KHz by setting the resonance frequency to about 0 Hz. Or let
It is possible to sense pronunciation.

That is, when the frequency of the resonance point of the magnetic circuit 7 is input from a signal source, the magnetic circuit 7 largely vibrates due to the resonance and the vibration is tactile. The vibration of the diaphragm 1 does not produce a sound that can be sensed due to the low frequency, and when the frequency of the resonance point of the vibrating portion of the diaphragm 1 is input from a signal source, the diaphragm 1 vibrates greatly due to resonance and generates sound. However, the vibration of the magnetic circuit 7 generated as a reaction of the vibration of the vibration plate 1 does not have such a large amplitude that the mass of the magnetic circuit 7 is large and cannot be followed due to the high frequency, so that it cannot be touched. .

[0008]

As described above, in the above-mentioned electro-mechanical-acoustic converter, the suspension 9a,
Since the relatively large weight of the magnetic circuit 7 including the magnetic circuit 9b vibrates greatly, it is more demanded to improve the reliability of the joint in order to improve the reliability quality of the electro-mechanical-acoustic transducer. It has been.

According to the present invention, the reliability of the joint is improved.
It is intended to improve the quality of the electric-mechanical-acoustic transducer.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an electro-mechanical-acoustic transducer according to the present invention is adhered and fixed on a diaphragm and a yoke made of a metal of a magnetic material having at least a surface plated with tin. A magnetic circuit formed of a magnet and disposed opposite the diaphragm, a voice coil having one end attached to the diaphragm and fitted in a magnetic gap of the magnetic circuit, and a metal obtained by laser welding the magnetic circuit. The suspension consists of a thin plate and a frame supporting the suspension. The surface of the yoke is tin-plated to improve the bonding strength, and the magnetic circuit is formed by laser welding between the yoke and the suspension. This is intended to improve the reliability of the bonding.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to the vibration plate formed of a magnet adhered and fixed on a yoke made of a metal of a magnetic material having at least a surface plated with tin. A magnetic circuit arranged opposite to the voice coil, a voice coil having one end attached to the diaphragm and fitted in a magnetic gap of the magnetic circuit, and a suspension made of a metal thin plate obtained by laser welding the magnetic circuit,
Each frame of the magnetic circuit is composed of a frame supporting this suspension, tin-plated on the surface of the yoke to improve the bonding strength with the magnet, and firmly joining the yoke and the suspension by laser welding. This is intended to improve the reliability of the bonding.

According to a second aspect of the present invention, the yoke according to the first aspect has a tin plating thickness of 3 μm or less, while maintaining the reliability of joining by laser welding between the yoke and the suspension. It can maintain the adhesive strength between the magnet and the magnet.

According to a third aspect of the present invention, the plating applied to the yoke according to the first aspect is tin plating under nickel, and the thickness of each plating is set to 3 μm or less, respectively, so that the distance between the yoke and the suspension is reduced. While maintaining the reliability of the joining by laser welding, the adhesion strength between the yoke and the magnet is maintained by tin plating, and the yoke can be rust-proofed by nickel plating on the base.

An embodiment of the electro-mechanical-acoustic converter according to the present invention will be described below with reference to FIGS. The same parts as in the prior art are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the same. A description will be given of a magnetic circuit including a suspension, particularly a relationship between a yoke and a suspension, which is a difference from the related art.

Reference numeral 4a denotes a yoke, which is a steel plate plated with tin under nickel (nickel plating aims to prevent rust, and tin plating aims to improve adhesion to the magnet 5).
The plating thickness is 3 microns or less for both nickel and tin. The suspensions 9a and 9b are formed of a stainless steel plate (thin plate).

Next, as a comparative example, Table 1 shows the results of comparison with a yoke made of a general plated steel plate (zinc plating under copper).

The yoke 4a and the suspension 9a,
9b, a YAG laser is used, and the laser beam guided from the optical fiber 10 is applied to the lens unit 1 as shown in FIG.
1, the yoke 4a and the suspensions 9a, 9b
At two opposite spots.

[0019]

[Table 1]

As shown in the above (Table 1), the yoke 4a
The bonding property of the magnet and the magnet 5 was such that the comparative example was judged to be slightly inferior, but the welding state was cracked in the comparative example, and that of the present embodiment was superior. Was observed, and in the case of the comparative example, the scattering of the plating metal on the lens of the laser device was observed.

These phenomena are as follows. In the comparative example, the boiling point of zinc plating is lower than the melting point of the stainless steel of the suspensions 9a and 9b, and the zinc plating evaporates or scatters during heating by laser irradiation, and welding cracks and blow holes are generated. It is considered that welding quality is degraded and inefficiency due to diffusion of heat on the plated surface by copper underplating promotes the above phenomenon.

It should be noted that scattering to the lens portion of the laser device
Adhesion of the evaporant is not preferable for maintenance.

On the other hand, in this embodiment, the melting point of stainless steel, tin plating, nickel plating, and steel sheet are each set to about 1500 ° C. or less and the boiling point is about 2300 ° C. It is considered that the welding was performed without increasing the depth and relatively scattering and evaporating the plated metal.

Next, the suspension 9 due to the difference in plating thickness is used.
Table 2 shows the comparison results of the welding states of the a, 9b and the yoke 4 with the YAG laser.

[0025]

[Table 2]

As shown in the above (Table 2), when the tin plating thickness is 3 μm or less, or when the nickel plating thickness is 3 μm or less.
It was confirmed that good welding was performed when the diameter was less than micron.

The thickness of the nickel plating and the thickness of the tin plating may be appropriately set to 3 μm or less in accordance with the required rust-preventive bonding purpose.

[0028]

As described above, according to the present invention, by applying tin plating under nickel to a yoke made of a magnetic material, it becomes possible to perform good welding of the yoke and the suspension by laser while maintaining the adhesive strength with the magnet. It is possible to provide an electro-mechanical-acoustic transducer excellent in practicality.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the electro-mechanical-acoustic transducer of the present invention.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is an explanatory view for explaining a state of welding between the yoke and the suspension, which is the main part.

FIG. 4 is a cross-sectional view of a conventional electro-mechanical-acoustic transducer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diaphragm 2 Frame 3 Voice coil 4a Yoke 5 Magnet 6 Upper plate 7 Magnetic circuit 8 Magnetic gap 9a, 9b Suspension

Claims (3)

[Claims] 1. A vibrating plate, a magnetic circuit formed of a magnet adhered and fixed on a yoke made of a metal of at least tin-plated magnetic material and disposed facing the vibrating plate, An electro-mechanical device comprising: a voice coil attached to a diaphragm and fitted into a magnetic gap of the magnetic circuit; a suspension made of a thin metal plate obtained by laser welding the magnetic circuit; and a frame supporting the suspension. Sound transducer. 2. The electro-mechanical-acoustic transducer according to claim 1, wherein the thickness of the tin plating applied to the yoke is 3 microns or less. 3. The electro-mechanical-acoustic converter according to claim 1, wherein the plating applied to the yoke is tin plating under nickel, and each plating thickness is 3 microns or less.