JP2002374595A - Eccentric speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eccentric speaker that adopts a very simple and easy means of ununiformizing the magnetic flux density in the gap of a magnetic circuit so as to cancel unbalanced moment of inertia caused by a biased center hole. SOLUTION: The speaker comprises; the magnetic circuit comprising a top plate 2 and a magnet and a yoke; and a vibration system comprising a voice coil 4, a diaphragm 1 with a center hole in a biased axis X, and a damper 5. In order to increase the magnetic flux density of a gap close to the center axis O of the diaphragm 1, the magnetic gap G1 between the pole and the top plate 2 is reduced, in order to reduce the magnetic flux density of a gap remote from the center axis O of the diaphragm 1, the magnetic gap G2 between the pole and the top plate 2 is increased so as to ununiformize the magnetic flux thereby correcting unbalanced moment of inertia.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentric loudspeaker for use in audio equipment, and more particularly, to an eccentric center hole formed in a cone, which eliminates imbalance in inertia moment by improving a magnetic circuit. The present invention relates to an eccentric loudspeaker in which the generation of abnormal sound at the time of cone vibration caused by the unbalance is improved.

[0002]

2. Description of the Related Art As one of deformed cones, there is known an eccentric cone in which a center hole of a diaphragm on which a voice coil is mounted is shifted to one side from an original center axis.

That is, in this type of loudspeaker, as shown in FIG. 4, a center hole is formed in an offset axis X which is deviated from an original center axis O of a diaphragm 30.
Since the width of the magnetic gap G formed between the inner peripheral portion 1 and the outer peripheral portion of the pole (not shown) is constant over the entire circumference, the center axis of the diaphragm 30 is naturally formed.
The mass of the diaphragm located outside (the left side in FIG. 4) of the biasing axis X in which the center hole is formed is smaller than the mass of the diaphragm on the opposite side (the right side in FIG. 4). , The whole diaphragm is on the left side (axis X
Vibration occurs in the state inclined to ₁ ), that is, the left side is lowered as shown by the dotted line, so that the voice coil 32 comes into contact with the inner peripheral portion of the top plate 31, generating abnormal noise or damaging the collision portion. And other problems arise.

For the purpose of preventing a problem (unbalance) at the time of vibration of the eccentric cone, for example, by partially changing the hardness of a damper or an edge, and further by the weight balance of the diaphragm, the deviation is controlled. In order to eliminate the imbalance of the moment of inertia caused by this, further, in Japanese Patent Application Laid-Open No. H11-155189, means for eliminating the imbalance of the moment of inertia by the weight balance of the diaphragm is specifically disclosed. .

[0005]

SUMMARY OF THE INVENTION In the above solution,
To change the hardness of the damper or the edge, it is necessary to change the shape of the damper or the edge to a complicated shape in accordance with the change. The means of adding a balancer to the diaphragm that has been eliminated substantially increases the mass of the diaphragm, which may cause a new problem and increase the manufacturing process of the diaphragm, thereby increasing costs. This is not a preferable means.

SUMMARY OF THE INVENTION In view of the above situation, the present invention eliminates the unbalance of the moment of inertia caused by displacing the center hole by extremely simple and easy means of making the magnetic flux density of the magnetic gap in the magnetic circuit non-uniform. It is intended to provide an eccentric loudspeaker which can be used.

In order to achieve the above object, an eccentric speaker according to the present invention comprises a magnetic circuit comprising a top plate, a magnet and a yoke, and a vibration system comprising a voice coil, a diaphragm having a center hole deviated, and a damper. In configuring, by making the magnetic flux density of the portion near the center of the diaphragm and the magnetic flux density of the portion far from the center non-uniform,
It is characterized by correcting imbalance of the moment of inertia.

More specifically, the eccentric loudspeaker of the present invention comprises a magnetic circuit comprising a top plate, a magnet and a yoke, a voice coil, a diaphragm having a center hole deviated,
When configuring a speaker with a vibration system composed of a damper, the magnetic gap formed between the pole and the top plate is reduced to increase the magnetic flux density of the magnetic gap located near the center of the diaphragm. In order to reduce the magnetic flux density of the magnetic gap located in the area, a large magnetic gap is formed between the pole and the top plate, and the imbalance of the moment of inertia is corrected by making the magnetic flux density non-uniform. It is an eccentric speaker.

[0009] In the present invention, the "center portion of the diaphragm" means a portion where the original center axis of the diaphragm exists.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an eccentric loudspeaker according to the present invention will be specifically described below with reference to the accompanying drawings.

As shown in FIG. 1, the eccentric loudspeaker of the present invention has a center hole on an offset axis X whose center is shifted in any direction (right side in FIG. 1) from the original center axis O of the diaphragm 1. In forming the magnetic gap, a magnetic gap G formed between the top plate 2 and a pole (not shown) constituting a magnetic circuit is formed on the left side with respect to the center of the bias axis X. ₁ and the magnetic gap G ₂ formed on the right side is made non-uniform as in the case of magnetic gap G ₁ <magnetic gap G ₂ , thereby eliminating the imbalance of the moment of inertia caused by biasing the center hole. Is the biggest feature.

More specifically, as shown in FIG. 2, when the magnetic gap G is formed between the pole 6 and the top plate 2 as shown in FIG. half portion which is positioned forms a magnetic gap G ₁ and a gap formed between the pole 6 and the top plate 2 constant, half portion which is positioned farther from the center axis side, pole 6 and the top a magnetic gap G ₂ is formed between the plate 2 and forms made wider than the magnetic gap G ₁ of the.

In FIG. 2, a half-circumferential portion of the diaphragm 1 which is located on the original center axis side of the diaphragm 1 with respect to the bias axis X is a pole 6.
Although forming a magnetic gap G _1, the magnetic gap G ₂ is formed on the half portion which is positioned farther from the center axis side of the magnetic gap formed between the top plate 2 and a uniform interval, against external constant pole 6, and the width to the inner diameter portion of the top plate 2 is fixed, a plurality of recesses 2a only different lengths, 2b, and the magnetic gap G ₂ to form 2c, the magnetic gap G ₁ <Although are configured to be magnetic gap G _2, short, about the offset axis X, the magnetic gap G ₁ is formed on the half portion which is positioned on the diaphragm 1 original central axis side, the central axis relationship between the magnetic gap G ₂ is formed on the half portion located farther from the side the side is, the magnetic gap G ₁ <long as the magnetic gap G ₂ the shape of the pole 6 and the top plate 2 particular of There is no limit and the gap is large How to set the like it is can be chosen freely as design parameters.

When the voice coil / coil section 4 is arranged in the magnetic gap G having the above-mentioned configuration in accordance with the center of the pole 6 to form a magnetic circuit, the magnetic gap G ₂
Since the magnetic force of naturally weaker than the magnetic force acting on the magnetic gap G ₁ side, the entire balance is maintained by appropriately determining the difference, the time of the vibration damper 5
Accurate up and down movement is achieved. In FIG. 1, reference numeral 3 denotes a voice coil bobbin.

[0015]

FIG. 3 is a schematic explanatory view showing an example of a composite speaker 10 using the eccentric speaker of the present invention.
Reference numeral 1 denotes a yoke having a pole 12 at its center, 13 denotes a ring-shaped magnet fixed on the yoke 11, 14
Is a top plate fixed on the magnet 13,
15 is a frame fixed on the top plate 14, 18 is an outer peripheral portion of the pole 12 and the top plate 1
4, a voice coil held in a magnetic gap formed between the voice coil and the inner peripheral portion, 16 a damper holding a voice coil bobbin 19 holding the voice coil 18 at a base end, and 17 a voice coil holding the voice coil An elliptical low-frequency vibration formed by fixing the neck portion to the outer peripheral portion of the upper end of the bobbin 19, fixing the outer peripheral portion to the outer peripheral portion of the frame 15 via the edge 23, and displacing the center hole. Board, 2
Reference numeral 2 denotes a mid / treble speaker mounted on a spacer 20 fixed to the pole 12 with bolts 21.

The magnetic circuit in the bass speaker constituting the composite speaker 10 employs the configuration shown in FIG. 2 described above. The magnetic gap on the semi-circumferential portion located on the original center axis side of the diaphragm 17 is The gap between the pole 12 and the top plate 14 is made uniform, and the magnetic gap on the semi-peripheral portion located farther from the center axis side is wider than the pole 12 having a constant outer diameter at the inner diameter portion of the top plate 14. Are formed by providing a plurality of concave portions having a constant length and different lengths.

The voice coil 18 of the loudspeaker having such a configuration is located in a magnetic gap set so that the magnetic flux density is high in the half circumference near the center axis of the diaphragm 17 and low in the far half circumference. Therefore, when the voice coil 18 is vibrated, the voice coil 18 can be moved up and down accurately without being biased to one side with the damper 16 as a center.

[0018]

According to the eccentric speaker of the present invention, when assembling a speaker using a diaphragm having a center hole at a position deviated from the original center, the magnetic flux density of the magnetic gap at the center is increased, and Extremely simple means of lowering the magnetic flux density of the magnetic gap on the opposite side farther away eliminates the unbalance of the moment of inertia caused by displacing the center hole from the original center axis and prevents high frequency resonance It was done.

In particular, in the eccentric speaker of the present invention, when forming the magnetic gap in which the voice coil moves up and down, the magnetic flux density of the original center axis side of the diaphragm and the magnetic gap density of the magnetic gap on the opposite side to the center axis side are determined. By making the voice coil non-uniform, contact with the pole due to rolling of the voice coil, generation of abnormal sound due to this contact, and damage to the speaker can be eliminated, and the mass of the diaphragm Has many advantages such as not increasing the

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a basic concept of an eccentric speaker of the present invention.

FIG. 2 is a plan view showing an embodiment of a magnetic gap which is a main part of the eccentric speaker of the present invention.

FIG. 3 is a schematic explanatory view of a composite speaker using the eccentric speaker of the present invention.

FIG. 4 is an explanatory diagram showing a vibration state of a conventional eccentric speaker.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Diaphragm 2, 14 Top plate 3, 19 Voice coil / bobbin 4, 18 Voice coil / coil part 6 Pole O Original center axis of diaphragm X Deflection axis G Magnetic gap G ₁ Magnetic gap with high magnetic flux density G ₂ Magnetic flux density Low magnetic gap 10 Composite speaker 11 Yoke 12 Pole 13 Magnet 15 Frame 16 Damper 17 Diaphragm 20 Spacer 21 Bolt 22 Medium / treble speaker

Claims (3)

[Claims] 1. A speaker comprising a magnetic circuit comprising a top plate, a magnet and a yoke, and a vibration system comprising a voice coil, a diaphragm having a center hole deviated, and a damper, which is close to a center of the diaphragm. An eccentric loudspeaker characterized by correcting the imbalance of the moment of inertia by making the magnetic flux density of a part and the magnetic flux density of a distant part non-uniform. 2. The method according to claim 1, wherein the non-uniformity of the magnetic flux density is achieved by increasing the magnetic flux density of a magnetic gap located near a central portion of the diaphragm and decreasing the magnetic flux density of a magnetic gap located far from the central portion. The eccentric speaker according to claim 1, wherein: 3. The method according to claim 2, wherein the non-uniformity of the magnetic flux density is achieved by forming a small magnetic gap at a position near the center of the diaphragm and a large magnetic gap at a position far from the center. Item 2. An eccentric speaker according to item 1.