JP2001016686A - Electro-mechanical-acoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce assembling man-hours due by reduction of components and to enhance vibration of an electro-mechanical-acoustic transducer used for a mobile phone or the like and having a vibration.sounding function. SOLUTION: The electro-mechanical-acoustic transducer consists of at least one suspension 16 whose one end is molded to a weight section 15 and whose other end is molded to a frame 17 that supports a moving section 18 consisting of a magnetic circuit 13 and the weight section 15 and of a baffle 8 fitted to the frame 17 supporting a diaphragm 8. Thus, the precision and the strength of a fulcrum of the suspension 16 can be enhanced and the vibration function can be enhanced by the weight section 15 provided through molding.

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.

[0002]

2. Description of the Related Art Conventionally, in a portable terminal device such as a portable telephone, as a means for notifying an incoming call, a small sounding body for generating a bell sound and a micromotor having a weight eccentrically attached to a rotating shaft for causing vibration are individually provided. It has been used by attaching. Furthermore, in order to listen to the talk of the other party, it is necessary to attach a speaker for receiving. 2. Description of the Related Art In recent years, along with the trend toward smaller, thinner, and lighter portable terminal devices such as portable telephones, those in which sound and vibration are realized by one electric-mechanical-acoustic converter have been commercialized.

FIG. 3 is a side sectional view of such an electro-mechanical-acoustic transducer, which explains the prior art.

According to FIG. 1, an outer peripheral portion of a diaphragm 1 is attached to a frame 2. A magnetic circuit 3a disposed opposite to the diaphragm 1 and a movable unit 3 formed of a weight 3b integrally formed with the magnetic circuit 3a or as a separate component mounted on the magnetic circuit 3a are provided. It is supported by the suspension 5 to form a mechanical vibration system. The suspension 5 is supported by the frame 2 to which the cover 6 is attached. A voice coil 7 has one end fixed to the diaphragm 1 and the other end inserted into the magnetic gap of the magnetic circuit 3a with a certain gap.

Next, the operation of the electro-mechanical-acoustic converter will be described. In the above-described electro-mechanical-acoustic converter, when an electric signal is applied to the voice coil 7, the voice coil 7 and the magnetic circuit 3a are connected. , The action / reaction force acts. Assuming that the force acting on the voice coil 7 is the acting force,
Due to the force, the diaphragm 1 on which the voice coil 7 is attached vibrates and emits sound.

The movable part 3 supported by the suspension 5 vibrates due to the reaction force acting on the magnetic circuit 3a, and the vibration is transmitted to the frame 2 via the suspension 5, and the frame 2 vibrates. Since the resonance frequency of the movable portion 3 is in a low frequency range, a remarkable vibration is obtained by applying the low frequency to the voice coil 7.

[0007]

However, the above-mentioned electro-mechanical-acoustic converter includes: One end of the suspension 5 is connected to the magnetic circuit 3a and the weight 3
Since the suspension 5 is attached by bonding or welding when it is attached to the movable portion 3 made of b or when one end of the suspension 5 is attached to the frame 2, the fulcrum of the suspension 5 is likely to vary, and the resonance frequency and vibration level of vibration are not stable. 2. The number of steps for joining the suspension 5 is large. 3. In order to obtain the joint strength of the suspension 5, it is necessary to secure a joint area, and it is difficult to reduce the size of the electric-mechanical-acoustic transducer. 4. A portable terminal device such as a mobile phone has a possibility of dropping due to its portability due to its portability, and a shock such as a drop applies a shock to a built-in electro-mechanical-acoustic converter, thereby deforming the suspension 5 or forming a joint. Damage occurs,
The vibration resonance frequency and vibration level change. There was a problem that.

[0008] The present invention solves the above-mentioned problems, stabilizes the assembling accuracy, and has little change in performance even when subjected to an impact.
It is intended to realize a small-sized electro-mechanical-acoustic transducer.

[0009]

In order to solve the above-mentioned problems, an electro-mechanical-acoustic transducer of the present invention comprises a frame, a diaphragm directly or indirectly mounted on an opening of the frame, and a vibration plate. A magnetic circuit disposed opposite to the plate, a voice coil having one end attached to the diaphragm and having a fixed gap provided in a magnetic gap of the magnetic circuit,
A weight portion formed by molding or attached to the magnetic circuit by a mold, and one end supporting a movable portion formed by the magnetic circuit and the weight portion is integrally formed with a mold portion of the movable portion, and the other end is formed. Consisting of at least one suspension integrally molded with the frame, both ends of the suspension can be accurately assembled by molding, so that the vibration resonance frequency and the vibration level can be stabilized. Can be obtained.

[0010]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, there is provided a frame, a diaphragm mounted directly or indirectly on an opening of the frame, and a magnetic plate arranged opposite to the diaphragm. A circuit, a voice coil having one end attached to the diaphragm and provided with a fixed gap in the magnetic gap of the magnetic circuit, and a weight portion formed by molding or attached to the magnetic circuit by molding,
One end supporting a movable portion formed by the magnetic circuit and the weight portion is integrally formed with a mold portion of the movable portion, and the other end is configured by at least one suspension integrally formed with the frame. By molding the suspension at the time of molding the weight and the frame, the fulcrum at both ends of the suspension can be assembled with high accuracy, and the vibration resonance frequency and the vibration level can be stabilized.

Further, even if the area of the joint portion of the suspension is small, the joining strength of the suspension can be obtained.
In addition to reducing the size of the electro-mechanical-acoustic transducer, even when the portable terminal device is dropped and a shock is applied to the built-in electro-mechanical-acoustic transducer, the vibration resonance frequency and the vibration due to the damage of the suspension joint are increased. The change in level can be prevented.

The invention according to claim 2 of the present invention uses a resin molding material in which a high specific gravity metal is blended in a mold part constituting a movable part, and increases the mass of a vibrating part even if it is small. And a large vibration level can be obtained.

According to a third aspect of the present invention, the suspension according to the first aspect prevents the rolling motion of the movable portion by supporting the movable portion at a position vertically symmetrical from the center of gravity of the movable portion. It is possible to prevent occurrence of abnormal sound due to contact of the movable portion with the frame due to rolling.

According to a fourth aspect of the present invention, the suspension according to the first aspect is formed three-dimensionally in an up-down direction, and the portable terminal device is dropped and incorporated therein. -Even if the sound transducer is impacted,
The stress generated in the suspension can be dispersed,
This prevents changes in vibration resonance frequency and vibration level by preventing permanent deformation of the suspension and preventing damage to the suspension joint.

According to a fifth aspect of the present invention, the gap between the baffle and the movable portion according to the first aspect is set within a range of elastic deformation of the suspension, and the suspension of the suspension caused by an external impact is provided. This prevents changes in the vibration resonance frequency and vibration level due to damage.

According to a sixth aspect of the present invention, the frame and the baffle according to the first aspect are provided with a fitting portion, and the weight portion and the frame are molded by a mold when the suspension is molded. The position of the movable part and the magnetic gap of the magnetic circuit with respect to the frame is precisely determined, and the movable part, the baffle, and the magnetic circuit A magnetic gap and a voice coil attached to a baffle via a diaphragm are assembled with a certain gap with high accuracy.

According to a seventh aspect of the present invention, the suspension of the first aspect is formed from a hoop-shaped lead frame. The suspension is formed by a lead frame, and is integrated with the weight portion and the frame by molding. The formation can contribute to reduction of the number of parts and automation of assembly.

Hereinafter, an embodiment of the electro-mechanical-acoustic converter of the present invention will be described with reference to FIGS.

(Embodiment 1) FIG. 1A is a side sectional view of an electro-mechanical-acoustic converter according to an embodiment of the present invention, and FIG. 1B is an exploded perspective view of the same. .

Referring to FIG. 1, reference numeral 8 denotes a diaphragm made of, for example, a film having a thickness of about 50 μm, which is attached to a baffle 9 made of resin or the like at the outer periphery. Reference numeral 10 denotes a yoke, which is a ferromagnetic material such as soft iron and has a bottomed cylindrical shape. 11
Is a magnet, which is formed of a neodymium permanent magnet, has a columnar shape, and is fixed to the center of the yoke 10. Numeral 12 denotes a plate made of a ferromagnetic material, which is arranged and fixed on the side of the diaphragm 8 of the magnet 11.

A magnetic circuit 13 is formed by the yoke 10, the magnet 11, and the plate 12, and a magnetic gap is formed by an inner peripheral surface of the yoke 10 and an outer peripheral surface of the plate 12.

Reference numeral 14 denotes a cylindrical voice coil, which is inserted into the magnetic gap, and one end of the voice coil 14 is attached to the diaphragm 8.

Reference numeral 15 denotes a weight portion formed of a material having a specific gravity of about 12 in which tungsten powder is mixed with a resin, and is fixed to the yoke 10 by molding.

Reference numeral 16 denotes a suspension having two arms extending in the circumferential direction extending in the circumferential direction. The central portion is formed into an arc shape in the vertical direction. One pair is symmetrically arranged around the position of the center of gravity, and one end is fixed to the weight portion 15 and the other end is fixed to the frame 17.

The magnetic circuit 13 and the weight 15 constitute a movable part 18 which operates relative to the frame 17, and the suspension 16 and the movable part 18 constitute a mechanical vibration system. In addition, 19 is a cover.

Since the magnitude of the vibration of the mechanical vibration system is proportional to the product of the mass and the acceleration of the movable part 18, the weight 15 is made smaller by using a composite material of resin and a metal powder of high specific gravity such as tungsten. Even in this case, the mass of the mechanical vibration system increases, and a large vibration can be taken out.

Since the suspension 16 is molded and fixed to the weight portion 15 and the frame 17 in a mold, the fulcrum of the suspension 16 is determined with high accuracy, the performance is stabilized, and the joint portion comes off unless the weight portion 15 and the frame 17 are broken. The bonding strength can be obtained even with a small area.

Since the suspension is formed three-dimensionally in the vertical direction by the arcuate shaped portion 16a of the suspension 16, the stress generated in the suspension 16 at the time of impact is dispersed, and the outer periphery of the movable portion 18 and the baffle 9 are formed. A gap 20 within the elastic deformation range of the suspension 16 is provided between the inner diameters of the suspension 16 and the inner diameter of the baffle 9 receives the outer circumference of the movable part 18 even when the movable part 18 moves by impact. The movable part 18 is returned to the original position without causing permanent deformation.

Further, the gap 20 between the movable portion 18 and the baffle 9 is set smaller than the gap between the magnetic gap and the voice coil 14, and the outer periphery of the movable portion 18 is received by the baffle 9 before the magnetic gap hits the voice coil 14. Therefore, the voice coil 14 can be prevented from being damaged.

The baffle 9 has a projection 9a fitted to the inner diameter of the frame 17, and the projection 9a and the frame 17
And the baffle 9 is attached to the frame 17. Movable part 18 and magnetic circuit 1 for frame 17
The position of the magnetic gap 3 is precisely determined because one end of the suspension 16 is fixed to the weight portion 15 and the other end is fixed to the frame 17. Therefore, it is only necessary to provide a fitting portion between the frame 17 and the baffle 9 and to assemble. The movable part 18 and the baffle 9, the magnetic gap of the magnetic circuit 13, and the voice coil 14 attached to the baffle 9 via the diaphragm 8 can be accurately assembled and provided with a certain gap.

The operation of the electro-mechanical-acoustic converter configured as described above will be described. Voice coil 1
When an electric signal is applied to 4, an action / reaction force acts between the voice coil 14 and the magnetic circuit 13. Assuming that the force acting on the magnetic circuit 13 is a reaction force, the reaction force is applied to the movable portion 18 including the weight portion 15 supported by the suspension 16 and the magnetic circuit 13, and the movable portion 18 vibrates. Become.

In particular, when the frequency of the electric signal applied to the voice coil 14 matches the resonance frequency of the mechanical vibration system, the movable part 18 vibrates greatly. The vibration of the movable portion 18 is transmitted from the suspension 16 to the frame 1.
7, the frame 17 vibrates. If the frame 17 is fixed to, for example, the housing of the portable terminal device, the housing can be vibrated to perform an operation such as calling.

However, if the movable portion 18 makes a rolling motion when vibrating, the outer periphery of the movable portion 18 and the inner diameter of the baffle 9 come into contact with each other and an abnormal sound is produced. Moving part 1 at equal distance to
8 is supported.

On the other hand, the diaphragm 8 vibrates due to an electric signal applied to the voice coil 14, and a sound is generated from the diaphragm 8.

Therefore, by constructing the electro-mechanical-acoustic converter as in the present embodiment, it is possible to stabilize the vibration performance and to prevent damage due to impact such as dropping and prevention of performance degradation.

Note that the weight 15 in the above embodiment is used.
Is provided integrally with the yoke 10 by molding, but the weight 15 may be separately provided and then both may be integrated by molding.

(Embodiment 2) Another embodiment of the present invention will be described with reference to FIGS. 2 (a) and 2 (b). The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 2 (a) is a side sectional view of an electro-mechanical-acoustic transducer according to another embodiment of the present invention, and FIG. 2 (b) is an exploded perspective view thereof.

According to the figure, the outer periphery of the diaphragm 8 is directly mounted on the frame 17 without using the baffle 9 of the first embodiment.

The suspension 16 and the lead terminals 21 are integrally formed by a lead frame 22 and are molded on the frame 17. As a result, the integration of parts and simplification of the assembling process can be further achieved.

[0041]

As described above, according to the electro-mechanical-acoustic converter of the present invention, the performance at the time of assembling is stabilized, and when the portable terminal device is dropped, the electro-mechanical-acoustic converter is subjected to impact. Even under the condition, the suspension, the voice coil, and the joint of the suspension can be prevented from being damaged, and the performance of vibration or sound generation can be prevented from deteriorating.

[Brief description of the drawings]

FIG. 1 (a) is a side sectional view of an embodiment of the electromechanical-acoustic converter of the present invention, and (b) is an exploded perspective view of the same.

FIG. 2 (a) is a side sectional view of the other embodiment, and (b) is an exploded perspective view of the same.

FIG. 3 is a side sectional view of a conventional electro-mechanical-acoustic transducer.

[Explanation of symbols]

 Reference Signs List 8 diaphragm 9 baffle 9a protrusion 10 yoke 11 magnet 12 plate 13 magnetic circuit 14 voice coil 15 weight 16 suspension 17 frame 18 movable part 19 cover 20 gap 21 lead terminal 22 lead frame

Claims (7)

[Claims] 1. A frame, a diaphragm mounted directly or indirectly on an opening of the frame, a magnetic circuit disposed to face the diaphragm, and a magnetic circuit having one end attached to the diaphragm. Supports a voice coil inserted with a certain gap in the magnetic gap, a weight portion formed by molding or attached to the magnetic circuit, and a movable portion composed of the magnetic circuit and the weight portion. An electro-mechanical-acoustic transducer comprising at least one suspension having one end integrally formed with the mold portion of the movable portion and the other end integrally formed with the frame. 2. The electric-mechanical-acoustic converter according to claim 1, wherein a resin molding material in which a high specific gravity metal is blended is used for a mold part constituting the movable part. 3. The electro-mechanical-acoustic converter according to claim 1, wherein the suspension supports the movable portion at a position vertically symmetrical from the center of gravity of the movable portion. 4. The electro-mechanical-acoustic transducer according to claim 1, wherein the suspension is formed three-dimensionally in a vertical direction. 5. The electro-mechanical-acoustic converter according to claim 1, wherein the diaphragm is mounted on the frame via a baffle, and a gap is provided between the baffle and the movable part at least within a range of elastic deformation of the suspension. vessel. 6. The electro-mechanical-acoustic converter according to claim 1, wherein a fitting portion is provided between the frame and the baffle. 7. The electro-mechanical-acoustic transducer according to claim 1, wherein the suspension is formed from a hoop-shaped lead frame.