JP2972108B2 - Sealed sound transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed acoustic transducer for use in, for example, a pool, a hot tub, or the sea.

[0002]

2. Description of the Related Art FIG. 3 shows a speaker as a conventional sealed acoustic transducer. In this, a diaphragm 2 is formed in a part of a container 1. This is configured by bonding a diaphragm to a cup-shaped vessel and sealing it. In the center of the diaphragm 2, a synthetic resin voice coil cylinder 3 constituting the voice coil unit 3.
0 is attached by an adhesive. A voice coil 31 is wound around the voice coil cylinder 30. Reference numeral 4 denotes a permanent magnet portion, which includes a central magnetic pole 40, a ring-shaped permanent magnet 41, and a ring-shaped magnetic pole 42.
The center magnetic pole 40 is attached to the bottom of the container 1 by the attaching portion 10 and is inserted into the cylinder 30. The permanent magnet 41 is mounted on the center magnetic pole 40 outside the cylinder 30. The magnetic pole 42 has a closed magnetic path formed so that the magnetic flux generated from the permanent magnet 41 intersects the voice coil 31 via the central magnetic pole 40 and the magnetic pole 42. Therefore, when a signal current is supplied to the voice coil 31, the voice coil unit 3 is displaced according to the magnitude of the signal current, and vibrates the diaphragm 2.

[0003]

However, as shown in FIG. 4, when the diaphragm 2 is used in water, the diaphragm 2 bends inward due to water pressure. Therefore, the cylinder 30 is distorted and abnormally approaches or separates from the permanent magnet portion 4, and the gap between the cylinder 30 and the permanent magnet portion 4 changes greatly. As a result, the conversion efficiency especially in the low frequency range is deteriorated, and a speaker device having desired frequency characteristics cannot be obtained. In addition, heat is generated due to the deterioration of the conversion efficiency, thereby distorting the cylinder 30 and the like. As a result, not only the conversion efficiency is deteriorated, but also the adhesive is deteriorated. Since this water pressure changes depending on water depth, waves, and the like, it is impossible to predict and design in advance.

Accordingly, an object of the present invention is to provide a hermetic acoustic converter in which the conversion efficiency is not affected even when the external pressure changes, and the frequency characteristics are kept good.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a sealed container having a diaphragm formed in part, and a diaphragm disposed opposite a voice coil portion attached to the diaphragm. And a permanent magnet section elastically attached to the acoustic transducer.

[0005]

In the sealed acoustic transducer according to the present invention, since the permanent magnet is attached to the diaphragm, the relative position with respect to the voice coil does not change even if the diaphragm bends due to external pressure.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a speaker of a sealed acoustic converter according to an embodiment of the present invention will be described. The same parts as those of the conventional device are denoted by the same reference numerals, and description thereof will be omitted.

The permanent magnet section 4 includes a voice coil cylinder 30.
Is attached to the diaphragm 2 by a ring-shaped elastic member 5 on the outside. 6 is a permanent magnet portion 4, a diaphragm 2, an elastic member 5
And a first space formed by the cylinder 30. 7
Is a second space formed by the center magnetic pole 40, the diaphragm 2, and the cylinder 30. 43 is the second space 7 is the container 1
These are through holes formed in the central magnetic pole 40 to communicate with the entire third space 8. Reference numeral 32 denotes a plurality of ventilation holes formed at the base of the cylinder 30 to communicate the first space 6 and the second space 7.

The elastic member 5 attaches and supports the permanent magnet portion 4 to the diaphragm 2 and does not resonate the permanent magnet portion 4 with respect to the sound signal frequency of the diaphragm 2. It has an elastic force to simultaneously displace the permanent magnet portion 4 inward when flexing inward by water pressure. This elastic force is formed in the elastic member 5 and a predetermined value is obtained by the slit 51.

Next, the operation of the embodiment of the present invention will be described. When a voice current is supplied to the voice coil 31, a relatively displacing force is generated between the voice coil unit 3 and the permanent magnet unit 4. Since the permanent magnet portion 4 is heavy, it is not substantially displaced, and the voice coil portion 3 is displaced so as to vibrate the diaphragm 2. On the other hand, the permanent magnet portion 4 does not vibrate due to the vibration of the diaphragm 2. This is because the permanent magnet portion 4 does not resonate with the audio frequency due to the support of the predetermined elastic member 5.

[0010] Therefore, the permanent magnet unit 4 for the audio signal.
Does not substantially displace, and only the diaphragm 2 vibrates. When the water pressure is large, the diaphragm 2 tries to bend inward, but the ring-shaped elastic member 5 acts to prevent the bending. Therefore, it does not bend greatly. However, some deflection occurs. In that case, the permanent magnet part 4
Also displaces inward and does not cause a change in the relative position with respect to the voice coil unit 3. Of course, even when the environment is lower than the external pressure or the internal pressure, the permanent magnet portion 3 is similarly displaced.

On the other hand, since the voice coil unit 3 does not directly contact the outside air, it is difficult to radiate the heat generated from this. In particular, the temperature of the first space in contact with the voice coil unit 3 is significantly increased.
Is connected to the space 8, so that the convection of air with this space is made smooth. Further, the through hole 43 communicates with the third space 8 to provide a busless effect.

In the present invention, the back side of the permanent magnet unit 4 is combined with the prevention of resonance of the permanent magnet unit 4 with respect to an audio signal and the smooth follow-up of deflection of the diaphragm 2 due to water pressure. It is also possible to fill the space with silicone rubber or the like having appropriate elasticity. Further, the contact-type acoustic transducer of the present invention can be used for outdoor use to withstand rain and humidity. Further, the sealed acoustic device of the present invention can be applied not only to a speaker but also to a microphone.

[0013]

According to the present invention, since the permanent magnet is attached to the diaphragm, even if the diaphragm bends due to external pressure, the relative position with respect to the voice coil does not change and the predetermined gap is always maintained. Therefore, it is possible to provide a sealed acoustic transducer that does not cause deterioration or fluctuation in sound quality even when a large external pressure is applied or the external pressure fluctuates during use.

The periphery of the voice coil section is separated from the entire space of the container by an elastic member for attaching the permanent magnet section to the diaphragm, but the heat generated from the voice coil section is formed by a hole formed in the voice coil cylinder. Convection is smoothly performed, and the heat radiation effect is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a hermetic acoustic device shinker showing one embodiment of the present invention.

FIG. 2 is a perspective view showing a voice coil unit of FIG. 1;

FIG. 3 is a cross-sectional view of a conventional sealed speaker device.

FIG. 4 is a sectional view showing a state where a large water pressure is applied in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Diaphragm 3 Voice coil part 30 Cylinder for voice coil 31 Voice coil 32 Vent hole 4 Permanent magnet part 43 Through hole

Claims (2)

(57) [Claims] 1. A sealed container having a diaphragm formed in a part thereof, and a permanent magnet portion disposed opposite to a voice coil portion attached to the diaphragm and elastically attached to the diaphragm. A waterproof acoustic converter characterized by the above-mentioned. 2. A closed magnetic circuit for a hermetically sealed container partially formed with a diaphragm, a voice coil cylinder mounted at the center of the diaphragm, and a voice coil wound around the voice coil cylinder. Forming a permanent magnet portion disposed to cover the voice coil portion, a ring-shaped elastic member for attaching the permanent magnet portion to the diaphragm at an outer periphery of a mounting position of the voice coil portion, and A sealed acoustic transducer comprising: a through hole formed in a position corresponding to the inside of the voice coil cylinder of the permanent magnet portion; and a ventilation hole formed in the voice coil cylinder.