JP2001103586A - Multifunctional sounding body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multifunctional sounding body where a different shape from that of a conventional sounding body is given to a part of components of the multifunctional sounding body so as to increase a vibration mass by itself or together with other means as the major purpose, where the vibration mass is increased while effectively utilizing the internal space of the sounding body as another purpose and where an effective shock resistant means is provided at the same time to prevent the sounding body from being damaged due to the increased mass of its magnetic circuit as the other purpose. SOLUTION: Magnetic pole pieces or permanent magnets being components of the magnetic circuit are formed to be a shape of convex lenses, the convex face is nearly set along with a projection face of a diaphragm, and a motion limit member is provided to the sounding body to provide anti-shock performance to the increased mass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a multifunctional sounding body which responds to a plurality of frequency bands and outputs an acoustic frequency or a lower frequency vibration.

[0002]

2. Description of the Related Art For example, an acoustic signal is output in response to an electric input having an acoustic frequency of several hundreds to several kHz, and
2. Description of the Related Art There is known a multifunctional sounding body that also performs vibration (vibration) output that can be sensed in response to an electrical input at a low frequency of about 0 to 100 Hz. Since a single acoustic transducer can generate a plurality of types of signals, it is highly effective as a means for reducing the size and cost of devices such as mobile phones. FIG. 3 schematically shows the structure of the conventional multifunctional sounding body.

FIG. 3 is a schematic cross-sectional view of a conventional multifunctional sounding body in which main parts have a substantially cylindrical shape. Reference numeral 1 denotes a housing which is made of synthetic resin and has a substantially cylindrical shape. Reference numeral 2 denotes a diaphragm for sound output, and the drive coil 3 is integrated. 4
Is a magnetic circuit, and a yoke 4a, a permanent magnet 4b, and a circular plate-shaped pole piece (also referred to as a top plate) 4c concentrate a driving magnetic field in a magnetic gap 4d. The magnetic circuit 4 is connected to the housing 1 by a support spring 5. 4e
Is a cylindrical additional mass which is fixed to the magnetic circuit 4 and serves as a weight for sufficiently lowering the natural frequency, and is included in the mass of the magnetic circuit 4 to increase the bodily sensation of low-frequency vibration in the audible range. The natural frequency of the magnetic circuit is about 10 to several tens Hz. The upper or lower surface of the housing 1 is fixed to an outer wall of a small electroacoustic device, a circuit board, or the like (not shown).

[0004] With such a configuration, the drive coil 3
When a driving current is input from an external circuit (not shown) to the magnetic circuit 4, an electromagnetic force is generated relatively to the magnetic circuit 4. If the driving current is at an acoustic or audio frequency, the magnetic circuit 4 does not respond because its natural frequency is much lower, and
Only vibrates and outputs sound. However, if the driving current has a low frequency close to the natural frequency of the magnetic circuit 4, the diaphragm 3 hardly responds, and the magnetic circuit 4 resonates and vibrates in the axial direction with a large amplitude. Then, in an environment where sound is disliked or, conversely, in an environment where noise is loud and an acoustic signal is inappropriate, a signal due to silent and sensible vibration is generated.

[0005]

When trying to enhance bodily sensation at low frequencies below the audible frequency, it is important that the vibrating mass be as large as possible. Therefore, in the prior art, as shown in FIG. 3, a ring-shaped additional mass 4e is fitted into the yoke 4a to increase the vibration mass. However, this additional mass is independent of the magnetic properties of the sounding body. If the mass of the magnetic circuit is increased anyway, the mass of the parts originally required for the magnetic circuit should be increased, and even if the increase in the mass is slight, the magnetic characteristics of the sounding body should be positive. It is desirable. In view of the demand for downsizing and thinning of the sounding body, and furthermore, of the acoustic electronic device in which the sounding body is built, it is desirable that the increased mass be placed in a space that has not been effectively used conventionally.

[0006] There is also a single-function sounding body as a speaker or a buzzer, which is an older technique, which can generate only sound output and cannot generate low-frequency sensible vibration. In these sounding bodies, the magnetic circuit is fixed to the housing, but in the above-mentioned conventional example, the magnetic circuit is movable and also serves as a vibrating mass, so that multiple functions can be realized. However, that created new problems. That is, since a magnetic circuit having a large mass is supported by a relatively soft support spring, when an impact due to a drop or the like is applied to an electronic device equipped with the sounding body, the heavy magnetic circuit is greatly displaced and the sounding body itself is displaced. This may cause deformation or breakage of the housing, the support spring, the coil, the diaphragm, or other adjacent components.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multifunctional sounding body, in particular, by giving a part of a magnetic circuit an unusual shape to increase the vibrating mass by itself or by using other means. It is to plan. Another object is to effectively utilize the internal space of the sounding body when increasing the mass of some parts of the magnetic circuit. Still another object is to simultaneously provide an effective shock-resistant means for preventing the sounding body from being damaged by the increased mass of the magnetic circuit.

[0008]

The structure of the multifunctional sounding body of the present invention has the following feature (1) in order to solve this problem. In addition, (2) the following features may be simultaneously provided.

(1) A housing, a diaphragm supported by the housing and vibrating by receiving an electromagnetic force of an acoustic frequency, and a relatively low-frequency vibration system elastically supported by the housing, A magnetic circuit having a relatively large mass including a permanent magnet for applying a magnetic field for generating the electromagnetic force to the diaphragm, wherein the diaphragm or the magnetic field corresponds to an electric input in a plurality of frequency bands. In a multifunctional sounding body whose circuit mainly oscillates in response, a pole piece forming a part of the magnetic circuit or a central portion of the permanent magnet is thickened.

(2) The diaphragm has a convex surface facing the outside of the housing, and the surface of the pole piece or the permanent magnet has a convex surface substantially parallel to the convex surface of the diaphragm.

(3) Most of the mass elements constituting the relatively low-frequency vibration system are the sum of the masses of the respective components constituting the magnetic circuit, and the spring element is a spring of a leaf spring supporting the magnetic circuit. Sex.

(4) The housing and the magnetic circuit are provided with a movement restricting member that comes into contact when the two attempt to make a relative displacement exceeding a predetermined value.

(5) The movement restricting member provided on the housing side projects in the inner circumferential direction, the movement limiting member provided on the magnetic circuit side projects in the outer circumferential direction, and one of them has the other thickness. That it is sandwiched while maintaining a gap in the vertical direction.

[0014]

FIG. 1 is a sectional view of a multifunctional sounding body according to a first embodiment of the present invention. Portions having functions common to those already described with reference to FIG. 3 are denoted by the same symbols and names, and redundant description will be omitted, and different portions will be described. First, what is characteristic of the present invention is that the pole piece (top plate) 4c is not formed in a disk shape as in the conventional example, but is provided with a shape having a thick central portion like a plano-convex lens. Is added to the oscillating mass. The outer wall of the yoke 4a has a sufficient thickness in the radial direction to further supplement the mass. Thus, the magnetic circuit 4 obtains a sufficient mass, and the additional mass (conventional example 4e) is omitted.

The yoke 4a is not fixed to the housing 1, but is supported by a flat support spring 5 having a flat shape as shown in FIG. ). The support spring 5 has an inner ring-shaped portion welded to the upper surface of a yoke 4a (not shown in FIG. 3) and four flexible arms outside the yoke 4a. Is insert-molded and fixed to the upper case 1a. As a result, the magnetic circuit 4 has a structure in which the housing 1 is hooked by a spring.

The mass of the magnetic circuit 4 mainly composed of the yoke 4a, the permanent magnet 4b and the pole piece 4c,
The natural frequency of the magnetic circuit 4 in the vertical direction is substantially determined by the spring property of the arm portion. Therefore, when a low frequency current input close to the natural frequency is applied to the drive coil 3, the magnetic circuit 4 resonates and vibrates with a large amplitude, and outputs a low frequency vibration that can be sensed.

The thicker central portion of the pole piece 4c is a magnetically significant and preferable shape. In this case, the pole piece 4c plays a role of radially bending the magnetic flux generated in the axial direction over the entire surface of the cylindrical permanent magnet 4b almost at right angles to reach the ring-shaped magnetic gap 4d from the inside. Since the magnetic flux density in the state should be large at the central portion of the pole piece 4c and small at the peripheral portion, a thicker cross section at the central portion can equalize the internal magnetic flux density, reduce the leakage magnetic flux, and reduce the magnetic properties of the material used. The magnetic permeability can also have a margin.

The fact that the central portion of the pole piece 4c is thickened has a meaning in effective use of the internal space of the multifunctional sounding body. Since the diaphragm 2 needs to provide rigidity even if it is thin, the diaphragm 2 usually has a convex surface (substantially a part of a spherical surface) whose outside faces outward. The substantially spherical surface of the pole piece 4c is substantially parallel to the curve of the diaphragm 2, and the increased thickness of the pole piece 4c fits well in the space behind the diaphragm 2 and the thickness of the multifunctional sounding body. Does not increase.

An upper case 1a and a lower case 1b are fixedly overlapped on a resin-made casing 1, and movement restricting members 1c and 1d projecting inward of a cylindrical main body, respectively.
Is provided. A ring-shaped space having a U-shaped cross section is formed in an intermediate portion between the two movement restricting members. The yoke 4a is integrally formed from a soft magnetic metal material, and has a movement limiting member 4f protruding outward on the outer peripheral portion.

The movement restricting member 4f on the outer periphery of the yoke 4a is fitted in the ring-shaped space formed in the housing 1 and having a "U" cross section. However, the interval is set so as not to come into contact with the inner wall at the amplitude giving the specified vibration output.
However, when an impact or the like is applied and the magnetic circuit 4 is excessively displaced in any direction with respect to the housing 1, the movement limiting member 4f
Comes into contact with the movement limiting member 1c or 1d on the housing side, and the maximum amount of displacement is limited. When the direction of displacement is also substantially cylindrical and the radial direction (lateral direction) of the sounding body is also the outermost deep portion of the "U" -shaped sectional space and the cylindrical surface at the root of the motion restricting member 4f, the motion restricting function. May be fulfilled.

FIG. 2 is a sectional view of a multifunctional sounding body according to a second embodiment of the present invention. The difference from the first embodiment in FIG. 1 lies in the shapes of the permanent magnet 4b and the pole piece 4c, both of which show cross sections different from FIG. Other structures are common to those of the first embodiment. In this example, the permanent magnet 4b has a convex lens shape to gain the vibration mass,
A dish-shaped pole piece 4c is adhered to the convex surface. In the case of this example, the volume of the permanent magnet 4b itself increases, and therefore, the amount of magnetic flux can also increase. Although the magnetic flux distribution inside the pole piece 4c is not as ideal as that of the first embodiment, the effective magnetic flux collected in the magnetic gap can be increased even if the leakage magnetic flux increases somewhat. In an extreme case, a structure in which the dish-shaped pole piece 4c is omitted can be considered. In any case, the space behind the diaphragm 2 can be effectively used as in the first embodiment. As a modified example of the present embodiment, a meniscus lens-shaped magnetic pole piece having a convex lens-shaped permanent magnet and a concave surface adapted to the surface thereof may be used.

FIGS. 4A and 4B show a plan view of a movement restricting member according to the present invention. FIG. 4A is a plan view showing a part of one embodiment of the present invention, and FIG. 4B is a plan view showing another embodiment. It is. Each plan view shows only the housing 1 and the yoke 4a, and the other parts are not shown. Since the motion restricting members of the present invention have a complicated structure, (1) when the magnetic circuit generates a vibration output, the air inside the "U" -shaped cross-sectional space is generated by the motion restricting member 4f. It has to move around the outer narrow flow path, causing fluid resistance to the vibration of the yoke,
There is a problem of insufficient vibration amplitude. (2) There is a problem in assembling the housing and the yoke. The solutions to these problems in each embodiment will be described below.

In the first embodiment shown in FIG.
As a countermeasure of the above (1), a large number of small holes 4g are formed in the movement restricting member 4f, and the flow path of air is increased to avoid an increase in fluid resistance. In the figure, a small hole is provided only on the yoke side. However, if a hole is also provided on the movement restricting member on the facing housing side to allow air to escape to the outside, the resistance will be further reduced. The position and shape of the small holes are also free, and a number of notches may be provided instead of the holes. As a countermeasure of the above (2) for providing the movement restricting member without interruption over the entire circumference, as described in the description of FIG. 1, the housing is made of the two cases of the case 1 and the case 2 and the yoke 4a is sandwiched between the cases. While assembling.

In the second embodiment shown in FIG. 4 (b), each movement restricting member is not provided on the entire circumference but is divided by a large notch, and a space region in which air is confined as a plurality of sectors is defined by a circumferential length. Only part of the height was reduced, and only one of the upper and lower sides was significantly reduced. Of course, a small hole may be further provided on each sector. Also, since the movement restricting members 1c and 1d are provided so as not to overlap with each other,
And facilitates integral injection molding without separating them. When the yoke 4a is assembled, the movement limiting member 4f is moved to the movement limiting member 1.
By rotating about 22.5 ° (in the case of 4 sectors) from the position overlapping with the moving members 1c and 1d
Then, the yoke 4a and the support spring (not shown) are fixed to each other by welding or the like.
Take measures. Alternatively, the yoke and the support spring may be fixed first, the structure may be fitted from the back side of the housing, and then the periphery of the support spring and the housing may be fixed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Although the shape of the pole piece or the permanent magnet in the present invention is relatively clearly defined, their materials and detailed shapes, or the basic structure of the sounding body combined with them, the presence or absence of the motion limiting member or its shape structure, By changing the shape of the spring or the like or mixing the features of the components, it is possible to adopt other different embodiments. For example, the movement limiting member may be provided at a different position or on another member, or at least one of the movement limiting members may be made of a soft material or coated. Further, in the illustrated embodiment, two movement restricting members are provided on the housing side and one yoke side. However, it is obvious that substantially the same configuration and effect can be obtained even if the number relation is reversed.

[0026]

(1) In the present invention, the mass of the magnetic circuit can be increased by first devising the shape of the pole piece or the permanent magnet to make it convex.

(2) By making the convex shape of the pole piece or the permanent magnet conform to the convex shape of the diaphragm, the internal space of the multifunctional sounding body can be effectively used and the size can be prevented from being increased.

(3) By using only the mass of the magnetic circuit as the vibration mass, no additional mass is required, and the number of parts of the multifunctional sounding body can be reduced.

(4) Further, by providing a movement restricting member in the housing and the magnetic circuit, it is possible to prevent the sounding body from being damaged by the application of a shock to a large mass.

(5) An effective movement limiting member structure can be provided by engaging a member projecting inward from the housing with a member projecting outward from the magnetic circuit side.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a multifunctional sounding body according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a multifunctional sounding body according to a second embodiment of the present invention.

FIG. 3 is a schematic sectional view of a conventional multifunctional sounding body.

FIG. 4 is a plan view of a movement restricting member used in the present invention, wherein (a) and (b) show different embodiments.

FIG. 5 is a plan view showing an example of a shape of a support spring used in the present invention.

[Explanation of Signs] 1 housing 1a upper case 1b lower case 1c movement limiting member 1d movement limiting member 2 diaphragm 3 drive coil 4 magnetic circuit 4a yoke 4b permanent magnet 4c magnetic pole piece 4d magnetic gap 4e additional mass 4f movement limiting member 4g Hole 5 Support spring 5a Spoke

Continued on the front page (72) Inventor Tetsuya Akasaki 1-23-1 Kagureji, Fujiyoshida-shi, Yamanashi F-term in Citizen Electronics Co., Ltd. (Reference) 5D012 BB03 FA04 FA10 GA01 5D017 AA11

Claims (5)

[Claims] 1. A housing, a vibrating plate supported by the housing and vibrating by receiving an electromagnetic force of an acoustic frequency, and a relatively low-frequency vibration system elastically supported by the housing, A magnetic circuit having a relatively large mass including a permanent magnet for applying a magnetic field for generating the electromagnetic force to the plate, wherein the diaphragm or the magnetic circuit corresponds to electrical inputs in a plurality of frequency bands. 1. A multi-function sounding body which vibrates mainly in response to the problem, wherein a pole piece forming a part of the magnetic circuit or a central portion of the permanent magnet is thickened. 2. The vibration plate according to claim 1, wherein the surface of the pole piece or the permanent magnet has a convex surface substantially parallel to the convex surface of the vibration plate. Item 1. The multifunctional sounding body of Item 1. 3. Most of the mass elements constituting the relatively low-frequency vibration system are the sum of the masses of the respective parts constituting the magnetic circuit, and the spring element is a spring property of a leaf spring supporting the magnetic circuit. The other function type sounding body according to claim 1 or 2, wherein: 4. A movement restricting member provided on the housing and the magnetic circuit, wherein the movement restricting member comes into contact when the two attempt to make a relative displacement exceeding a predetermined value. 3 multifunctional sounding body. 5. The movement restricting member provided on the housing side projects in an inner peripheral direction, the movement restricting member provided on the magnetic circuit side protrudes in an outer peripheral direction, and one of them has the other thickness. 5. The multi-function sounding body according to claim 4, wherein the multi-function sounding body is configured to be sandwiched while maintaining a gap in the direction.