JPH02268595A - Low leakage magnetic flux speaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a low leakage flux type speaker used in various audio equipment and video equipment.

2. Description of the Related Art A conventional low leakage magnetic flux type speaker of this type has a configuration as shown in FIG. That is, a diaphragm e is bonded to the periphery of a frame 6, which is formed by molding a magnetic circuit 4 formed by sandwiching a main magnet 1 between an upper plate 2 and a lower plate 3, and this diaphragm A voice coil 7 for driving the diaphragm 6 is held in the center by a damper 8 and coupled to fit into the magnetic gap 9, and paper is placed on the surface of the coupling portion of the diaphragm 6 with the voice coil 7. The speaker body was constructed by adhering a dust cap 1Q made of non-magnetic material such as cloth, resin film, or aluminum. Furthermore, a canceling magnet 11 magnetized in the opposite direction to the main magnet 1 was provided on the back surface of the lower plate 3, and a shield cover 12 was provided to cover the entire magnetic circuit.

Problems to be Solved by the Invention However, the conventional low leakage magnetic flux type subey force of this type is
The leakage magnetic flux from the magnetic circuit 4 is reduced by the effect of However, the problem is that there are cases where

The present invention solves these conventional problems and provides a low-leakage magnetic flux type speaker that has excellent performance against leakage magnetic flux.

Means for Solving the Problems In order to solve the above problems, the present invention has developed a dust cap made of magnetic metal in order to reduce the leakage magnetic flux generated from the center ball of the lower plate to the front of the speaker, which normally has a large amount of leakage magnetic flux. Something consisting of a body, a magnetic metal body made of paper,
The dust cap itself is made of paper mixed with magnetic material powder, which is covered with resin, etc., and the dust cap itself has a magnetic shielding effect to absorb magnetic flux leaking from the center ball of the lower plate toward the front of the speaker. This is what I did.

Effects With the above configuration, in addition to the magnetic shielding effect of the conventional canceling magnet and shield cover, it also prevents magnetic leakage from the center ball of the lower plate toward the front of the speaker by preventing dust from forming on magnetic metal bodies. Magnetic shielding is provided by a cap, a dust cap made of a composite of a magnetic metal body, paper, resin, etc., or a dust cap made of paper mixed with magnetic material powder, and leakage of magnetic flux to the outside is significantly reduced.

Embodiment Hereinafter, a low leakage flux type speaker which is an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a diaphragm 26 is attached to the periphery of a frame 25, which is constructed by molding a magnetic circuit 24 formed by sandwiching a main magnet 21 between an upper plate 22 and a lower plate 23 using resin. A voice coil 27 for driving this diaphragm 26 is attached to a damper 2 at the middle part.
A dust cap 30 made of a magnetic metal such as iron is adhered to the surface of the diaphragm 26 to form a speaker body. It consists of a cancellation magnet 31 magnetized in the opposite direction to the main magnet 21 on the back side, and a shield cover 32 that covers the entire magnetic circuit.

Here, regarding the dust cap 3o, in addition to the embodiment shown in FIG. 1, there are dust caps made of a composite with paper or a composite with resin that have a structure to suppress iron resonance as shown in FIG. 33, and as yet another example,
As shown in Figure 3, in order to prevent the sound pressure level of the speaker from decreasing due to the increased weight of the dust cap due to the use of magnetic metal bodies, the dust cap is made by mixing paper with magnetic material powder such as iron powder. 34.

By doing this, the dust caps 30, 33, and 34 in the embodiment described above can magnetically shield magnetic leakage from the center ball of the lower plate 23, which usually causes a lot of magnetic leakage, from the outside. The leakage magnetic flux to is significantly reduced.

Effects of the Invention As described above, in addition to the magnetic shielding effect of the conventional canceling magnet and shield cover, the present invention provides a dust cap made of a magnetic metal body, a dust cap made of a composite of a magnetic metal body and paper or resin, and a dust cap made of a composite of a magnetic metal body and paper or resin. Since it is also magnetically shielded by a dust cap mixed with magnetic material powder, it is possible to provide an unprecedented ultra-low magnetic leakage speaker, and its industrial value is extremely large.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a speaker in an embodiment of the present invention;
2 and 3 are sectional views of a speaker according to another embodiment of the present invention, and FIG. 4 is a sectional view of a conventional speaker. 21... Main magnet, 22... Upper plate, 23... Lower plate, 24...
...Magnetic circuit, 25...Frame, 26...
...Diaphragm, 27...Voice coil, 28.
...damper, 29...magnetic cap,
30...Dust cap made of magnetic metal material,
31...Cancellation magnet, 32...
・・Shield cover, 33・・・・Dust cap made of a composite of magnetic metal body and paper or resin, 34・
...Dust cap mixed with magnetic material powder. Name of agent: Patent attorney Shigetaka Awano and one other person

Claims (1)

[Claims] A frame made of resin is made by integrally molding an outer magnetic type magnetic circuit consisting of a main magnet sandwiched between an upper plate and a lower plate, and a diaphragm is bonded to the periphery of this frame. A voice coil that fits into the magnetic gap of the magnetic circuit is coupled to the diaphragm, and a dust cap made of a magnetic metal material is attached to the front of the diaphragm, a composite dust cap in which the magnetic metal material is covered with a material such as paper or resin, or a magnetic metal material. A low leakage magnetic flux type speaker having a paper dust cap made of a mixed material adhered thereto, a canceling magnet adhered to the back surface of the lower plate, and a shield cover disposed to cover the magnetic circuit.