JP3188825B2 - Speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin speaker having a magnetic circuit utilizing a repulsive magnetic field.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, two thin disk-shaped or ring-shaped magnets 1 and 2 are arranged with the same polarity facing each other via a nonmagnetic spacer or a magnetic yoke 3. Various thin speakers having a magnetic circuit have already been proposed and provided. The arrow in the figure indicates the flow of the magnetic flux, and the voice coil (not shown) is in a strong repulsive magnetic field.
To efficiently drive the voice coil and, consequently, the diaphragm.

[0003] In such a repulsive magnetic field type magnetic circuit, since the magnetic flux density distribution is symmetric, the distortion due to the driving force in the low frequency range is reduced, but the current distortion in the middle and high frequency range due to the eddy current is reduced. There is a growing demand for reduction. As a method of reducing this kind of current distortion, for example, as shown in FIG. 5, there is a method in which a so-called center pole 20 of an inner magnet type magnetic circuit is covered with a non-magnetic short ring 21. In the drawing, reference numeral 22 denotes a plate, and 23 denotes a magnetic gap between the plate 22 and the center pole 20. In addition, an external magnet type is known in which a short ring is provided in a similar portion.

[0004]

However, in the magnetic circuit having such a configuration, since the magnetic gap 23 between the center pole 20 and the plate 22 is provided with a short ring, the magnetic gap 23 must be widened accordingly. And the magnetic flux density is reduced.

The present invention has been proposed in view of the above, and it is an object of the present invention to provide a loudspeaker capable of reducing current distortion without lowering magnetic flux density and improving high-frequency characteristics. To provide.

[0006]

According to the present invention, there is provided a loudspeaker in which two magnets 1 and 2 opposing surfaces are arranged at the same polarity to form a magnetic circuit, and a voice coil 6 is arranged in a magnetic field on the outer periphery thereof. In the above, the short ring 4 is provided on the outer peripheral surface of the magnets 1 and 2, and the outer peripheral portion of the yoke or the spacer 3 interposed between the magnets 1 and 2 is protruded to be substantially flush with the outer peripheral surface of the short ring 4. By doing so, the above object is achieved.

[0007]

According to the present invention, the same poles of the magnets 1 and 2 are arranged to face each other, and the voice coil is arranged in a strong repulsive magnetic field generated on the outer peripheral side thereof. For this reason, even if the short ring is provided, there is no disadvantage that the magnetic flux density decreases as in the case of the magnetic circuit shown in the conventional example. Then
In the present invention, the short ring 4 made of a non-magnetic conductive material is used.
Are provided on the outer periphery of the two magnets 1 and 2 arranged opposite to each other, thereby short-circuiting the eddy current generated in the magnetic circuit to reduce the electromagnetic distortion, suppress the impedance rise in the middle to high range of the voice coil 6, and increase the height of the speaker. The region characteristics have been improved.

[0008]

FIG. 1 shows an embodiment of the present invention. 1, 2
Are two thin disk-shaped or ring-shaped magnets which are opposed to each other with a ring yoke or spacer 3 interposed therebetween. These magnets 1 and 2 are magnetized in the thickness direction thereof and are arranged to face each other with the same polarity. A repulsive magnetic field is generated between the opposing surfaces. As these magnets 1 and 2 constituting the magnetic circuit, for example, an anisotropic sintered magnet (neodymium magnet) is used.

Reference numeral 4 denotes a ring-shaped non-magnetic conductive material provided on the entire outer periphery of each of the magnets 1 and 2, which is generally called a short ring. This material is gold,
Appropriate ones among silver, copper, aluminum etc. were adopted,
Also, the thickness is appropriately selected as needed, such as the shapes of the magnets 1 and 2.

[0010] In a magnetic circuit of a loudspeaker, electromagnetic distortion occurs due to the non-linearity of the magnetic permeability due to the material, and as described above, it is known to use a short ring as a measure for improving this adverse effect. However, as a method of using a conventional dynamic type speaker, a method of covering a short ring on a pole piece of a magnetic circuit is generally adopted. In this case,
The magnetic flux density decreases.

In the present invention, in a so-called double magnet type magnetic circuit utilizing a repulsive magnetic field, attention is paid to the fact that a strong magnetic field is obtained on the outer periphery of the magnets 1 and 2 and the magnetic flux density does not decrease. 1,2
A short ring 4 is provided on the entire outer circumference of the to short-circuit the eddy current generated in the magnetic circuit, thereby suppressing an increase in impedance in middle and high frequencies. In this case, the outer peripheral surface of the short ring 4 and the outer peripheral surface of the yoke or the spacer 3 are substantially flush.

FIG. 3 shows an example of a speaker provided with the magnetic circuit of the present invention. In this example, a yokeless type having two magnets 1 and 2 opposed to each other with a spacer 3 interposed therebetween is used to reduce the thickness and weight of the magnetic circuit. It may be what was.

In FIG. 1, reference numeral 5 denotes a substantially bowl-shaped frame having a window 5a. The magnets 1 and 2 constituting a magnetic circuit are disposed substantially at the center of the frame 5, and a surrounding repulsive magnetic field is generated. A voice coil 6 is provided.

An inner peripheral portion of a cone-shaped diaphragm 7 is connected to a central portion of an outer periphery of the voice coil 6, and an outer end portion of the diaphragm 7 is connected to an outer peripheral portion of the frame 5 through an edge 8. ing.

A small-diameter conical sub-cone 9 is provided at the center of the diaphragm 7 on the front side. The neck of the inner periphery of the sub-cone 9 is coupled to the outer periphery of the voice coil 6, and a dust-proof center cap 10 is provided at the center of the sub-cone 9. The inner periphery of the damper 11 is connected to a substantially central portion of the outer periphery of the voice coil 6, and the outer periphery of the damper 11 is connected to a supporting portion 5 b formed on the frame 5 and formed of a step. Further, the magnetic circuit is fixed on a supporting portion 5c formed of a convex step formed at the center of the bottom of the frame 5, and a speaker is configured.
Needless to say, the magnetic circuit can be applied to other flat speakers.

FIG. 3 shows impedance characteristics with respect to frequency. In the figure, a is the present invention, and b is a conventional example without the short ring 4. According to the present invention, an increase in impedance can be suppressed and the mid-high frequency characteristics can be improved.

[0017]

As described above, according to the present invention, in a speaker in which the opposing surfaces of the two magnets 1 and 2 are arranged at the same polarity and the voice coil 6 is arranged in a magnetic field on the outer periphery thereof, Since the short ring 4 is provided on the entire outer periphery of the first and second parts to reduce the electromagnetic distortion, there is an effect that an increase in impedance in a high frequency range is suppressed and high frequency characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic half sectional view of a magnetic circuit used in the present invention.

FIG. 2 is an example of a speaker of the present invention.

FIG. 3 is an explanatory diagram illustrating impedance characteristics with respect to frequency.

FIG. 4 shows characteristics of a conventional magnetic circuit.

FIG. 5 is an explanatory cross-sectional view of an inner-magnet type speaker provided with a conventional short ring.

[Explanation of symbols]

 1, 2 magnet 3 yoke or spacer 4 short ring 5 frame 6 voice coil 7 diaphragm 8 edge 9 sub cone 10 dustproof cap 11 damper

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04R 9/06 H04R 1/24 H04R 9/00 H04R 9/02 102

Claims (1)

(57) [Claims] A loudspeaker in which a magnetic circuit is formed by arranging opposed surfaces of two magnets (1) and (2) at the same polarity, and a voice coil (6) is arranged in a magnetic field on the outer periphery thereof. A short ring (4) is provided on the outer peripheral surface of the magnets (1) and (2), and the outer peripheral portion of a yoke or spacer (3) interposed between the magnets (1) and (2) is projected.
A speaker characterized in that it is substantially flush with the outer peripheral surface of said short ring (4).