JP2004007761A - Electrical-to-mechanical-to-acoustic transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce man-hour for assembly by reducing the number of parts and to improve a vibrating function in an electrical-to-mechanical-to-acoustic transducer having a vibrating/sounding function to be used for a mobile telephone or the like. <P>SOLUTION: The electro-mechanical-acoustic transducer is composed of at least one suspension 16 whose one end for supporting a movable part 18 composed of a magnetic circuit 13 and a weight part 15 is fixed on the weight part 15 and whose other end is fixed on a frame 17, and a baffle 9 mounted on the frame 17 for supporting a diaphragm 8, accuracy and a strength of a supporting point of the suspension 16 can be improved and the vibrating function is also improved by the weight part 15 formed by molding a resin molding material in which a metal having high specific gravity is mixed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electro-mechanical-acoustic converter that performs a vibration or a sounding operation by an electric signal.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a portable terminal device such as a mobile phone uses a small generator that generates a bell sound and a micromotor with a weight eccentrically attached to a rotating shaft that causes vibration to be individually attached as means for notifying an incoming call. . 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, 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.
[0003]
FIG. 3 is a sectional side view of such an electro-mechanical-acoustic transducer, which explains the prior art.
[0004]
According to the figure, the outer peripheral portion of the diaphragm 1 is attached to the frame 2. A magnetic circuit 3a disposed opposite to the diaphragm 1 and a movable part 3 formed integrally with the magnetic circuit 3a or as a separate part and constituted by a weight 3b attached to the magnetic circuit 3a. A mechanical vibration system is supported by the suspension 5. 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.
[0005]
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, a signal is generated between the voice coil 7 and the magnetic circuit 3a. The action / reaction force works. Assuming that the force acting on the voice coil 7 is the acting force, the force causes the diaphragm 1 to which the voice coil 7 is attached to vibrate and emit sound.
[0006]
Also, 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]
[Problems to be solved by the invention]
However, the above-described electro-mechanical-acoustic transducer comprises:
1. When one end of the suspension 5 is attached to the movable portion 3 including the magnetic circuit 3a and the weight portion 3b or when one end of the suspension 5 is attached to the frame 2 by bonding or welding, the fulcrum of the suspension 5 tends to vary. Vibration resonance frequency and vibration level 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, which makes it difficult to reduce the size of the electric-mechanical-acoustic transducer.
It had the subject of.
[0008]
An object of the present invention is to solve the above-described problems and to realize a small-sized electro-mechanical-acoustic transducer with stable assembly accuracy, small performance change even when subjected to impact, and stable vibration characteristics. Things.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, an electro-mechanical-acoustic transducer according to the present invention includes a frame, a diaphragm directly or indirectly attached to an opening of the frame, and a magnetic plate arranged to face the diaphragm. A circuit, a voice coil having one end attached to the diaphragm and provided with a fixed gap in a magnetic gap of the magnetic circuit, and a weight formed or attached to the magnetic circuit by molding; One end supporting a movable portion composed of a magnetic circuit and the weight portion is integrally formed with a mold portion of the movable portion, and the other end is constituted by at least one suspension fixed to the frame, and the suspension is precisely formed by molding. Because it can be assembled, the vibration resonance frequency and vibration level can be stabilized, and even if the joint area is small, In which it is possible to obtain a bonding strength of Deployment.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
According to a first aspect of the present invention, there is provided a frame, a diaphragm mounted directly or indirectly on an opening of the frame, a magnetic circuit disposed to face the diaphragm, and one end of the vibration circuit. A voice coil attached to a plate and inserted with a certain gap in the magnetic gap of the magnetic circuit, a weight formed by molding or attached to the magnetic circuit, and the magnetic circuit and the weight One end supporting the movable portion is integrally formed with the mold portion of the movable portion, and the other end is constituted by at least one suspension fixed to the frame, and the weight portion and the suspension are molded. The fulcrum of the suspension can be assembled with high accuracy, and the vibration resonance frequency and the vibration level can be stabilized.
[0011]
In addition, even if the area of the joint portion of the suspension is small, the joining strength of the suspension can be obtained, the size of the electro-mechanical-acoustic transducer can be reduced, and the electric-mechanical device in which the portable terminal device falls and is built-in. Resin molding material that can prevent changes in vibration resonance frequency and vibration level due to damage to the suspension joint even when impact is applied to the acoustic transducer, and that mixes high specific gravity metal into the mold part that constitutes the movable part However, even if it is small, the mass of the vibrating part can be increased, and a large vibration level can be obtained.
[0012]
According to the second aspect of the present invention, the suspension according to the first aspect can prevent rolling motion of the movable part by supporting the movable part at a position vertically symmetrical from the center of gravity of the movable part. It is intended to prevent the occurrence of abnormal sound due to the contact of the movable part with the frame due to rolling of the movable part.
[0013]
According to a third aspect of the present invention, the suspension according to the first aspect is formed three-dimensionally in a vertical direction. Even if a shock is applied to the vessel, it can disperse the stress generated in the suspension, prevent permanent deformation of the suspension, and prevent changes in the vibration resonance frequency and vibration level by preventing damage to the suspension joint. is there.
[0014]
According to a fourth aspect of the present invention, the gap between the baffle and the movable part according to the first aspect is set within a range of elastic deformation of the suspension. This prevents changes in the resonance frequency and vibration level.
[0015]
According to a fifth 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 formed in a mold when the suspension is molded. Therefore, the position of the magnetic gap between the movable part and the magnetic circuit with respect to the frame is accurately determined, and the movable part and the baffle, and the magnetic gap between the magnetic circuit and the magnetic circuit can be formed simply by providing the frame and the baffle with the fitting part and assembling them. A voice coil attached to a baffle via a diaphragm can be assembled with a fixed gap with high accuracy.
[0016]
According to a sixth aspect of the present invention, the suspension of the first aspect is formed from a hoop-shaped lead frame, and the suspension is constituted by a lead frame, and is integrally formed with the weight portion and the frame by molding. This contributes to a reduction in the number of parts and automation of assembly.
[0017]
Hereinafter, an embodiment of the electro-mechanical-acoustic converter of the present invention will be described with reference to FIGS.
[0018]
(Embodiment 1)
FIG. 1A is a side sectional view of an electric-mechanical-acoustic converter according to an embodiment of the present invention, and FIG. 1B is an exploded perspective view of the same.
[0019]
According to the drawing, reference numeral 8 denotes a diaphragm made of a film having a thickness of, for example, about 50 μm, which is attached to a baffle 9 made of resin or the like at an outer peripheral portion. A yoke 10 is a ferromagnetic material such as soft iron and has a bottomed cylindrical shape. Reference numeral 11 denotes a magnet, which is formed of a neodymium permanent magnet, has a columnar shape, and is fixed to the center of the yoke 10. Reference 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.
[0020]
The yoke 10, the magnet 11, and the plate 12 form a magnetic circuit 13, and an inner peripheral surface of the yoke 10 and an outer peripheral surface of the plate 12 form a magnetic gap.
[0021]
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.
[0022]
Reference numeral 15 denotes a weight portion formed of a material having a specific gravity of about 12 obtained by mixing tungsten powder with a resin, and is fixed to the yoke 10 by molding.
[0023]
Reference numeral 16 denotes a suspension having two arms extending in the circumferential direction extending in the circumferential direction. The center portion is formed into an arc shape in the vertical direction, and the position of the center of gravity of the movable portion 18 in the vertical direction of the weight portion 15 is determined. And one end is fixed to the weight portion 15 and the other end is fixed to the frame 17.
[0024]
The magnetic circuit 13 and the weight 15 constitute a movable part 18 which operates relatively to the frame 17, and the suspension 16 and the movable part 18 constitute a mechanical vibration system. In addition, 19 is a cover.
[0025]
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 compact by using a material in which a resin and a metal powder having a high specific gravity such as tungsten are mixed. Also, the mass of the mechanical vibration system increases, and a large vibration can be taken out.
[0026]
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 accurately determined and the performance is stabilized, and the joint portion does not come off unless the weight portion 15 and the frame 17 are broken. The bonding strength can be obtained even in a small area.
[0027]
Further, 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 circumference of the movable portion 18 and the inner diameter of the baffle 9 are reduced. A gap 20 within the elastic deformation range of the suspension 16 is provided between the suspension 16 and the inner diameter of the baffle 9 receives the outer periphery of the movable portion 18 even when the movable portion 18 is moved by impact. The movable part 18 is returned to the original position without being raised.
[0028]
Further, the gap 20 between the movable part 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 part 18 is received by the baffle 9 before the magnetic gap hits the voice coil 14. Damage to the coil 14 can also be prevented.
[0029]
The baffle 9 has a projection 9 a that fits into the inner diameter of the frame 17. The baffle 9 is attached to the frame 17 by fitting the projection 9 a with the inner diameter of the frame 17. The position of the magnetic gap between the movable part 18 and the magnetic circuit 13 with respect to the frame 17 is accurately determined because one end of the suspension 16 is fixed to the weight 15 and the other end is fixed to the frame 17. The movable part 18 and the baffle 9, and the magnetic gap of the magnetic circuit 13 and the voice coil 14 attached to the baffle 9 via the diaphragm 8 are accurately provided with a fixed gap by merely assembling the fitting part. Can be.
[0030]
The operation of the electro-mechanical-acoustic converter configured as described above will be described. When an electric signal is applied to the voice coil 14, 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 composed of the weight portion 15 supported by the suspension 16 and the magnetic circuit 13, and the movable portion 18 vibrates. Become.
[0031]
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 section 18 vibrates greatly. The vibration of the movable portion 18 is transmitted from the suspension 16 to the frame 17, and the frame 17 vibrates. If the frame 17 is fixed to, for example, a housing of the portable terminal device, the housing can be vibrated to perform an operation such as calling.
[0032]
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. Supports the movable part 18.
[0033]
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.
[0034]
Therefore, by configuring the electro-mechanical-acoustic transducer as in the present embodiment, it is possible to realize stabilization of vibration performance and prevention of damage due to an impact such as a drop and performance degradation.
[0035]
Although the weight portion 15 in the above embodiment is provided integrally with the yoke 10 by molding, the weight portion 15 may be provided separately and then both may be integrated by molding.
[0036]
(Embodiment 2)
Another embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0037]
FIG. 2A is a side sectional view of an electro-mechanical-acoustic converter according to another embodiment of the present invention, and FIG. 2B is an exploded perspective view of the same.
[0038]
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.
[0039]
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 the simplification of the assembling process are further enabled.
[0040]
In each of the above-described embodiments, the weight portion 15 has been described as being made of a mixture of a resin and a high specific gravity metal such as tungsten. However, the weight portion 15 is made of a metal powder so that the specific gravity is higher than that of the magnetic circuit. Then, the weight portion 15 may be formed.
[0041]
【The invention's effect】
ADVANTAGE OF THE INVENTION As mentioned above, according to the electro-mechanical-acoustic converter of this invention, while the performance at the time of an assembly is stabilized, even if an electro-mechanical-acoustic converter receives a shock when a portable terminal device is dropped, a suspension will be sufficient. And the voice coil and the suspension joint 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 one embodiment of an electro-mechanical-acoustic converter of the present invention, FIG. 2 (b) is an exploded perspective view thereof, and FIG. 2 (a) is a side sectional view of another embodiment. (B) Exploded perspective view of the same [FIG. 3] Side sectional view of a conventional electric-mechanical-acoustic converter [Description of reference numerals]
Reference Signs List 8 diaphragm 9 baffle 9a projection 10 yoke 11 magnet 12 plate 13 magnetic circuit 14 voice coil 15 weight 16 suspension 17 frame 18 movable section 19 cover 20 gap 21 lead terminal 22 lead frame

Claims (6)

A frame, a diaphragm directly or indirectly attached to an opening of the frame, a magnetic circuit disposed opposite to the diaphragm, and one end attached to the diaphragm and fixed to a magnetic gap of the magnetic circuit. A voice coil inserted with a gap therebetween, a weight formed or attached to the magnetic circuit by molding, and one end supporting a movable portion composed of the magnetic circuit and the weight being movable. An electro-mechanical-acoustic converter comprising at least one suspension fixed to the frame at the other end integrally formed with a mold portion of the movable portion, wherein a resin having a high specific gravity metal blended in the mold portion constituting the movable portion An electro-mechanical-acoustic transducer using a molding material. 2. The electro-mechanical-acoustic transducer according to claim 1, wherein the suspension supports the movable part at a position vertically symmetrical from the center of gravity of the movable part. The electro-mechanical-acoustic transducer according to claim 1, wherein the suspension is formed three-dimensionally in a vertical direction. The electro-mechanical-acoustic transducer according to claim 1, wherein the diaphragm is mounted on the frame via a baffle, and further, a gap is provided between the baffle and the movable portion at least within a range of elastic deformation of the suspension. The electro-mechanical-acoustic converter according to claim 1, wherein one end of the suspension is integrally formed with the weight portion, the other end is also integrally formed with the frame, and a fitting portion is provided between the frame and the baffle. 2. The electro-mechanical-acoustic converter according to claim 1, wherein the suspension has one end integrally formed with the weight portion and the other end integrally formed with the frame, the suspension being formed from a hoop-shaped lead frame.

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