JPH05183990A - Dome-shaped speaker - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the magnetic flux density in a magnetic gap section by installing an acoustic absorbing material containing magnetic material inside the pole section to reduce the adverse effect due to the back pressure on a speaker diaphragm. CONSTITUTION:A ring-shaped magnet 6 is installed near the upper outer peripheral section of a discoid bottom plate 7 with a through hole whose thickness of the pole is as thick as thickness t1 of a top plate 5, and at the top of which a doughnut-shaped top plate 5 is installed. The conventional acoustic absorbing material is made of non-magnetic substance, while a magnetic substance (for example, steel wool) is used for an acoustic absorbing material 8. The foamed resin containing the magnetic substance may be used for it as the acoustic absorbing material 8. Thus, the magnetic flux density in the magnetic gap section can be improved by using the magnetic acoustic absorbing material 8 acoustic absorbing material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dome type speaker used for an audio output device and the like.

[0002]

2. Description of the Related Art A typical conventional example will be described with reference to FIG.
Reveal FIG. 2 is a half sectional view of a conventional dome type speaker.
The pole thickness of the top plate 5 is
Thickness t ₁Has a through hole that is about the same size as
In the vicinity of the upper outer peripheral edge of the disk-shaped bottom plate 7,
A magnet-shaped magnet 6 is attached, and further above it
Donut-shaped top plate 5 is attached
It In addition, a non-magnetic sound absorbing material 18 is provided inside the through hole.
(For example, glass wool) is attached. vibration
The edge 2 of the plate 1 is mounted on top of the top plate 5.
It is fixed to the frame 3. Of the bottom plate 7
A magnetic gap is provided between the upper end 9 and the inner surface 10 of the top plate 5.
Is supported by the diaphragm 1 and the edge 2 here.
The voice coil 4 is located.

[0003]

In the dome type speaker, the through hole diameter of the pole portion of the bottom plate must be made as large as possible in order to minimize the adverse effect of back pressure on the speaker diaphragm. However, in the above-described conventional configuration, there is a problem in that the cross-sectional area of the pole portion of the speaker magnetic circuit becomes small, so that magnetic saturation occurs and the magnetic flux density in the magnetic gap portion decreases.

The present invention solves the above-mentioned conventional problems, makes it possible to minimize the adverse effect of back pressure on the speaker diaphragm, and prevent the decrease in the magnetic flux density in the magnetic gap. .

[0005]

In order to solve the above problems, the speaker of the present invention has a structure in which a sound absorbing material containing a magnetic material is used inside the through hole of the pole portion of the bottom plate.

[0006]

With this structure, the sound absorbing material attached to the inside of the through hole of the pole portion of the bottom plate can also be used as the magnetic path, so that the reduction of the magnetic flux density in the magnetic gap portion can be suppressed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The sound absorbing material attached to the inside of the pole is different from that of the related art, and the other structures are the same as those described in the related art. Therefore, the same reference numerals are given and the description thereof will be omitted. Although the conventional sound absorbing material 18 is a non-magnetic material,
In the embodiment of the present invention, a magnetic material (for example, steel wool) is used as the sound absorbing material 8. Although steel wool is used as the sound absorbing material in this embodiment, it goes without saying that a foamed resin containing a magnetic material may be used as the sound absorbing material.

[0008]

As is apparent from the description of the above embodiment, the present invention uses the magnetic sound absorbing material as the sound absorbing material.
The magnetic flux density in the magnetic gap portion can be increased as compared with the case where a non-magnetic sound absorbing material is used. For example, the outer diameter φ125 of the bottom plate, the through hole diameter φ46 of the pole, the thickness 8 of the bottom plate, the outer diameter φ130 of the magnet, the inner diameter φ75, the thickness 20, the outer diameter φ125 of the top plate,
Inner diameter 62, thickness 7, sound absorbing material thickness 14 (all units are in millimeters), when steel wool is used as the sound absorbing material, the magnetic flux in the magnetic gap is greater than when using conventional non-magnetic sound absorbing material. The density can be increased by about 5%.

Further, since the sound absorbing material attached to the inside of the through hole of the pole portion of the bottom plate can also be used as the magnetic path, the adverse effect of back pressure on the speaker diaphragm can be minimized and the magnetic gap portion The reduction of magnetic flux density can be suppressed, the output sound pressure can be increased, the electric braking works well, the damping improves, and the sound with a good sense of speed can be produced with great industrial value. It is a thing.

[Brief description of drawings]

FIG. 1 is a half sectional view of a dome type speaker according to an embodiment of the present invention.

FIG. 2 is a half sectional view of a conventional dome type speaker

[Explanation of symbols]

 5 Top plate 6 Magnet 7 Bottom plate 8 Sound absorbing material containing magnetic material (steel wool, etc.)

Claims (1)

[Claims] 1. An air-core thick-walled ring-shaped bottom plate is provided under a cylindrical pole portion, a ring-shaped magnet is provided in the vicinity of an upper outer peripheral edge of the bottom plate, and a thick-walled ring-shaped top is provided on the upper portion thereof. A dome-shaped speaker having a plate, a magnetic gap being formed in the gap between the upper portion of the pole portion and the air core portion of the top plate, and a sound absorbing material containing a magnetic material being attached to the inner surface of the pole portion.