JP2000308182A - Magnetic circuit and loudspeaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the magnetomotive force in magnetic void by providing a center yoke, a 1st plate on which a cylindrical magnetic is provided side by side in one direction of the center yoke and the outer circumference of the center yoke is provided with a through hole and a box-shaped yoke surrounding an almost rectangular 2nd plate where the other ends of plural magnets are connected. SOLUTION: This magnetic circuit 10 comprises a bottom plate yoke 11 composed of rectangular plate material, a yoke 13 being also used as a plate and a subplate 14 composed of a 1st plate. Left and right, and front and rear side wall parts where the rectangular cover part of the yoke 13 is made a 2nd plate 13a are made a yoke 13b, and a through hole 13c through which a center yoke 15 can pass is made on one side of the plate 13. Ferrite magnets 16a to 16c including the subplate 14 and the yoke 15 are included in the yoke 13, and subsequently the yoke 11 is fixed to the bottom plate of the yoke 13 by spot welding, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small elliptical speaker and a magnetic circuit suitable for use in the speaker, and more particularly to a small-sized magnetic circuit having a strong magnetomotive force and a speaker.

[0002]

2. Description of the Related Art Conventionally, as a magnetic circuit used for a small speaker, a magnetic shield type cancel magnet has been used.
The present application proposes a magnetic circuit in which the magnetomotive force of a magnetic gap in which a voice coil is pivotally pivoted is increased and the driving force is approximately twice as large as that of a conventional magnetic circuit using one magnet. ing.

FIG. 5 is a sectional side view of a main part of the above-described magnetic circuit. In FIG. 5, reference numeral 1 denotes a yoke made of a substantially disk-shaped metal, which has a columnar center pole 2 at the center of the disk, is integrated with the yoke 1, and has a substantially inverted T-shaped cross section. Have been. S, N on the yoke 1 in the thickness direction
Concentric first magnet that becomes a cancellation magnet magnetized with
The magnets 3 are joined via an adhesive or the like.

[0004] A first plate 4 made of concentric metal is bonded on the first magnet 3 with an adhesive or the like, and a first concentric metal plate serving as a second main magnet is formed in the first direction in the thickness direction.
A second magnet 5 magnetized with N and S in the direction opposite to the thickness direction of the magnet 3 is bonded on the first plate 4 with an adhesive, and the second magnet 5 is formed of a concentric metal. The second plate 6 is joined with an adhesive or the like to form a magnetic circuit.

A magnetic gap 9 formed between the inner diameter of the first plate 4 and the outer diameter of the center pole 8 in such a magnetic circuit.
A voice coil 8 wound around a voice coil bobbin 7 pivotally attached to a frame or the like in a vertical direction via a diaphragm is interposed therein, and an acoustic signal is supplied to the voice coil 8 to drive the diaphragm. are doing.

[0006] According to the magnetic circuit having the above-described configuration, the N pole of the first magnet 3 passes through the magnetic gap 9 via the yoke 1 and the center pole 2 and the S plate of the first magnet 3 from the first plate 4. First magnetic flux φ flowing in the magnetism to the pole
₁ and the second plate 6 from the N pole of the second magnet 5
And the magnetic flux φ ₂ flowing from the first plate 4 to the S pole of the second magnet 2 via the magnetic gap 9 via the center gap 2 and the magnetic gap 9 via the center pole 2. As compared with the case where the use efficiency of the outer magnet type magnet is only about 1/3, the magnetomotive force of the magnetic gap 9 can be increased and the driving force of the diaphragm can be almost doubled. Have been.

[0007]

In the above-described conventional magnetic circuit and the loudspeaker using this magnetic circuit, since the outer magnetic circuit is used, the inner diameters of the first and second magnets 3 and 5 are reduced. Since the center pole 2 cannot have a diameter larger than the diameter of the center pole, a voice coil having a large diameter cannot be used when a small-diameter magnet is used, so that the driving force is limited.

Further, in an external magnet type magnetic circuit, the amplitude due to the movement of the diaphragm is generally determined by the thickness of the magnet. In the case of a thin and small magnet, the amplitude of the diaphragm cannot be increased, so that a large input is applied to the speaker. In this case, the height direction of the magnetic circuit is increased, and the depth of the speaker is increased as a whole.

The present invention is intended to solve the above-mentioned problems, and it is possible to increase the magnetomotive force of the magnetic gap 9 by using a small magnet in a magnetic circuit, and to double or more the driving force of the diaphragm. It is an object to provide a magnetic circuit and a magnetic shield type speaker.

[0010]

According to the magnetic circuit of the present invention, a substantially rectangular first plate having a center yoke and a plurality of columnar magnets arranged in one direction of the center yoke, and an outer periphery of the center yoke are transparent. A second plate having a substantially rectangular shape having a through hole serving as a magnetic gap portion to which the other of the plurality of magnets is joined, and a box-shaped yoke surrounding the second plate. is there.

The speaker according to the present invention is a speaker having a vibration system driven by a voice coil swingably pivoted in a magnetic gap formed between a center yoke and a hole formed in a plate. And a magnetic circuit in which a plurality of columnar magnets are arranged in a direction deviated from.

According to the magnetic circuit of the present invention and the loudspeaker using the magnetic circuit, the magnetomotive force of the plurality of small magnets is concentrated in one magnetic gap, and the driving force of the diaphragm can be more than doubled. Since there is no need to insert a center pole into the inside diameter of the magnet, the voice coil diameter can be selected to any size regardless of the magnet diameter. Further, since the small columnar magnets are juxtaposed in the longitudinal direction of the longitudinal plate, a magnet suitable for a tone soil type cabinet or an elliptical speaker having a small minor axis and a large major axis can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic circuit of the present invention and a speaker using the magnetic circuit will be described below with reference to FIGS.

FIG. 1 is a perspective view showing an assembled state of the magnetic circuit of the present invention, FIG. 2 is an explanatory view of mounting a magnet on the magnetic circuit of the present invention, FIG. 3 is an explanatory view of a magnetic path of the magnetic circuit of the present invention, and FIG. It is a top view and a side sectional view showing one example of a form of a speaker using a magnetic circuit of the present invention.

The configuration of the magnetic circuit of the present invention will be described with reference to FIGS. 1 and 2A to 2C. In FIG. 1, a magnetic circuit 10 includes a bottom plate yoke 11 made of a substantially rectangular plate material, a box-shaped plate / yoke 13, and a sub-plate 14 serving as a first plate.

The left, right, front and rear side walls of the box-shaped plate / yoke 13 having a rectangular lid portion formed as the second plate 13a are formed as yokes 13b, and the center yoke 15 can pass through one side of the plate 13. A through hole 13c is formed.

As shown in the plan view of FIG. 2C and the side sectional view of FIG. 2D, the sub-plate 14 is formed by bending a part of one end of a substantially rectangular metal plate downward at a right angle. A step 14a having a stepped cross section is formed, and a magnet guide 14b is formed.
The through-holes 14c are formed by pressing at the same time when the rectangular sub-plate 14 is formed.

A convex portion 14d (or a through hole) is provided on the step portion 14a.
Is formed, and guided by a through hole (or a convex portion) formed in the center of the bottom of the center pole 15, and the stepped portion 1 is formed through an adhesive.
4a.

Similarly, a plurality of small-diameter concentric cylindrical ferrite magnets 16a, 1 having a counterbore hole at the bottom guided by a magnet guide 14b of the sub-plate 14.
6b, 16c} are bonded onto the sub-plate 14 via an adhesive.

Next, a plurality of ferrite magnets 16a,
An adhesive is applied to the upper surfaces of the plates 16b and 16c and is bonded to the back side of the second plate 13a of the plate / yoke 13. At this time, a gap guide is inserted into the outer periphery of the center yoke 15 through the through hole 13c to insert a magnetic gap (FIG. 2).
(See (B)) 17 is assembled so as to have a predetermined gap width.

In the above description, a case has been described where a plurality of ferrite magnets 16a, 16b, 16c # and a center pole 15 are mounted on the sub-plate 14 and mounted on the plate / yoke 13. However, the center pole 15 is joined to the sub-plate 14. Is a plurality of ferrite magnets 1
6a, 16b, 16c} are bonded to the back side of the plate 13a of the plate / yoke 13 and then fixed on the step portion 14a of the sub-plate 14 through the gap 13c via the gap guide. .

As described above, the ferrite magnets 16 a and 16 including the sub-plate 14 in the plate / yoke 13
b, 16c} and the center yoke 15 are built in,
A magnetic circuit 10 as shown in FIG. 3 is formed by fixing the bottom plate yoke 11 to the bottom surface of the plate / yoke 13 by an appropriate method such as spot welding.

The sub-plate 14 described with reference to FIGS. 2C and 2D is formed by bending the substantially rectangular sub-plate 14 to form a step 14a, and the center pole 15 is fixed to the step 14a. 2 (A) and 2 (B)
May be configured as shown in FIG.

FIG. 2A is a plan view of the sub-plate 14 shown in FIG. 2B, FIG. 2B is a side sectional view of a main part, and the sub-plate 14 is formed as shown in FIG. The center pole 15 is formed of a simple rectangular metal plate, and the center pole 15 is provided with guide through holes 14f and ferrite magnets 16a, 16b, 16c.
Drill a through hole 14g slightly larger than the outer diameter of c ‥‥, insert cylindrical ferrite magnets 16a, 16b, 16c ‥‥ into the through hole 14g, and fix them together with an adhesive or the like, and at the bottom of the center pole 15 The guide protrusion formed in the above is inserted into the guide hole 14f, and the gap guide is covered with the center pole to be joined to the second plate 13a formed of a single plate via the plurality of ferrite magnets 16a, 16b, 16c. .

The yoke 18 shown in FIG. 2B has a box-like shape made of a metal, in which the bottom plate yoke 11 and the left and right front and rear yokes 13b are integrated with each other, in contrast to the configuration shown in FIG.
In this case, not only the gap of the magnetic gap 17 can be easily set but also the sub-plate 14 can be easily configured as compared with FIG.

Further, a plurality of ferrite magnets 16a, 16b, 16c # may be joined between the lower side of the sub-plate 14 and the bottom plate yoke 11, as shown by the broken line in FIG. In this case, the centering of the magnetic gap 17 with respect to the second plate 13a of one sheet is further facilitated.

In the above description, the magnetic gap 17 is connected to the center pole 1
Although only the through-hole 13c opposed to No. 5 is drilled, when a plurality of driving units are provided, a plurality of ferrite magnets 16a, 16
The diaphragm is driven at a plurality of positions by increasing the heights of the b and 16c by the thickness of the plate 13a and forming a through hole having a diameter larger than the required outer diameter of the ferrite magnet 16c and interposing a voice coil or the like. Alternatively, it is possible to easily configure a multi-way speaker.

FIG. 3 is a side sectional view of one embodiment of the magnetic circuit 10 assembled as described above. Referring to FIG. 3, the magnetomotive force (magnetic force) of the magnetic gap 17 is large. The point will be described.

In FIG. 3, three small-diameter ferrite magnets 16a, 16b and 16c are arranged in parallel on the sub-plate 14. However, since each magnet operates in the same manner, only the magnetic flux of the magnetic path of the first magnet 16a is provided. Will be described.

The magnetic flux emitted from the N pole of the first magnet 16a is applied to the second plate 13a → the magnetic gap 17 → the center pole 15 → the sub plate 14 → the first magnet 1
The magnetic flux φ ₁ passing through the magnetic gap 17 via the magnetic path of the S pole of 6a and the N pole of the first magnet 16a → the second plate 13a → the yoke 18 → the second plate 13a → the magnetic gap 17 → Center pole 15 → Sub plate 14 →
The magnetic flux φ passing through the magnetic path to the S pole of the first magnet 16a
₂

Second and third magnets 16b, 16c
‥‥ also generates the same magnetic flux φ ₁ and φ ₂
3a, the yoke 18, and the magnetic saturation in the sub-plate 14 and the case where the magnetic fluxes cancel each other, the number of magnets is set to N
In this case, the total magnetic flux φ ₀ = N × (φ ₁ + φ ₂ ) is not obtained, but the driving force (magnetomotive force) almost twice as large as that of the conventional driving force is obtained as in FIG. I have confirmed.

FIGS. 4A and 4B show a configuration in which the above-described magnetic circuit is used for an elliptical speaker. FIG.
4A is a plan view of the elliptical speaker, and FIG. 4B is a side sectional view.

In FIG. 4A and FIG.
A frame 20 formed in an elliptical shape is attached to a.
An edge 21 is provided on an outer peripheral portion of the frame 20, and the outer peripheral portion of the cone-shaped elliptical diaphragm 22 is held by the edge 21 with an arrow paper 29 or the like.

On the other hand, a voice coil bobbin 23 is mounted on the inner peripheral portion of the diaphragm 22. A voice coil 24 is wound around the voice coil bobbin 23. The voice coil 24 is formed by the plate 13a and the center pole 15. It is designed to be inserted into the magnetic gap 17.
Reference numeral 25 denotes a damper for holding the voice coil 24 in the magnetic gap 17, and reference numeral 28 denotes a cap joined to an upper portion of the voice coil bobbin.

An audio signal from an input terminal provided at a predetermined position outside the speaker box is supplied to a speaker terminal 26 via a connection line, and the audio signal from the terminal 26 is supplied to a voice via a tinsel wire 27. It is supplied to the coil 24.

In the above-described configuration, since the magnetic circuit 10 can use a very small ferrite magnet or the like, the width of the magnetic circuit (see the horizontal width w in FIG. 1) can be reduced, and the width direction is short and the length direction is long. This is a magnetic circuit advantageous for the elliptical speaker. The speaker is not limited to the elliptical speaker, and may be a rectangular speaker that can be housed in an elongated cabinet like a tone soil.

According to the magnetic circuit and the loudspeaker of the present invention, the mass production is excellent with a very simple structure, the width w of the magnetic circuit can be reduced, and a strong magnetomotive force (magnetic force) can be generated in the magnetic gap. The effect is high, and a voice coil having a diameter which is not affected by the inner diameter of the magnet to be used can be obtained.

[0038]

According to the present invention, the following effects (1) to (6) can be obtained. (1) A sub-plate and a yoke plate are bonded to both sides of a set of magnets using two or more magnets, and a magnetic gap of an arbitrary size can be created between the sub-plate and the yoke plate. (2) The magnetic force of one set of magnets is concentrated on one circular magnetic gap, and the magnetic force (magnetomotive force) of the magnetic gap becomes almost 2, which is very strong. (3) Since there is no need to create a magnetic gap by inserting a center pole into the inside diameter of the magnet, the voice coil diameter can be set to any size regardless of the opening of the inside diameter of the magnet. (4) A plurality of magnetic gaps can be easily formed, and a speaker having a wide directivity can be obtained. (5) Since a very small magnet can be used, the width of the magnetic circuit can be made extremely small, and the width of the magnetic circuit is very short, and the magnetic circuit is very advantageous for a speaker having a long diameter in the length direction. (6) A magnetic shield type speaker and a magnetic circuit can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an assembled state of an embodiment of a magnetic circuit according to the present invention.

FIG. 2 is an explanatory view of mounting a magnet showing one embodiment of the magnetic circuit of the present invention.

FIG. 3 is an explanatory diagram of a magnetic path showing one embodiment of the magnetic circuit of the present invention.

4A and 4B are a plan view and a side sectional view illustrating one embodiment of the speaker of the present invention.

FIG. 5 is a side sectional view of a main part showing an embodiment of a conventional magnetic circuit.

[Explanation of symbols]

10 ‥‥ magnetic circuit, 13 ‥‥ plate combined yoke, 13
a ‥‥ second plate, 14 ‥‥ subplate (first plate), 15 ‥‥ center pole, 16a, 16b,
16c @ magnet

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[Procedure amendment]

[Submission date] April 26, 1999 (1999.4.2
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art Conventionally, as a magnetic circuit used for a small speaker, a magnetic shield type cancel magnet has been used.
The present applicant proposes a magnetic circuit in which the magnetomotive force of the magnetic gap where the voice coil is pivotally pivoted is increased and the driving force is approximately twice as large as that of the conventional magnetic circuit using one magnet. are doing.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

A magnetic gap 9 formed between the inner diameter of the first plate 4 and the outer diameter of the center pole 2 in such a magnetic circuit.
A voice coil 8 wound around a voice coil bobbin 7 pivotally attached to a frame or the like in a vertical direction via a diaphragm is interposed therein, and an acoustic signal is supplied to the voice coil 8 to drive the diaphragm. are doing.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006] According to the magnetic circuit having the above-described configuration, the N pole of the first magnet 3 passes through the magnetic gap 9 via the yoke 1 and the center pole 2 and the S plate of the first magnet 3 from the first plate 4. First magnetic flux φ flowing in the magnetism to the pole
₁ and the second plate 6 from the N pole of the second magnet 5
And the magnetic flux φ ₂ flowing through the magnetic path from the first plate 4 to the S pole of the second magnet 5 via the magnetic gap between the center pole 2 and the magnetic gap 9 via the center pole 2. As compared with the case where the use efficiency of the outer magnet type magnet is only about 1/3, the magnetomotive force of the magnetic gap 9 can be increased and the driving force of the diaphragm can be almost doubled. Have been.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010]

According to the magnetic circuit of the present invention, a substantially rectangular first plate in which a center pole and a plurality of columnar magnets are juxtaposed in one direction of the center pole, and an outer periphery of the center pole are transmitted. A second plate having a substantially rectangular shape having a through hole serving as a magnetic gap portion to which the other of the plurality of magnets is joined, and a box-shaped yoke surrounding the second plate. is there.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

A speaker according to the present invention has a vibration system driven by a voice coil pivotally mounted in a magnetic gap formed between a center pole and a through hole formed in a plate. And a magnetic circuit in which a plurality of columnar magnets are arranged in a direction deviated from.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

The configuration of the magnetic circuit according to the present invention will be described with reference to FIGS. 1 and 2A to 2D. In FIG. 1, a magnetic circuit 10 includes a bottom plate yoke 11 made of a substantially rectangular plate material, a box-shaped plate / yoke 13, and a sub-plate 14 serving as a first plate.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

As described above, the magnet 16a such as ferrite including the sub-plate 14 in the plate / yoke 13
The magnetic circuit 10 as shown in FIG. 3 is formed by fixing the bottom plate yoke 11 to the bottom surface of the plate / yoke 13 by an appropriate method such as spot welding after the center poles 16b, 16c} and the center pole 15 are built in. .

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

[0038]

According to the present invention, the following effects (1) to (6) can be obtained. (1) Since the center pole is arranged at a position deviated from the magnet, the center pole diameter can be selected to an arbitrary size. (2) The magnetic force of one set of magnets is concentrated in one circular magnetic gap, and the magnetic force (magnetomotive force) of the magnetic gap becomes almost twice as large as the conventional one, and becomes very strong. (3) Since there is no need to create a magnetic gap by inserting a center pole in the inside diameter of the magnet, the voice coil diameter can be set to an arbitrary size regardless of the opening of the inside diameter of the magnet. (4) A plurality of magnetic gaps can be easily formed, and a speaker having a wide directivity can be obtained. (5) Since a very small magnet can be used, the width of the magnetic circuit can be extremely reduced, and the magnetic circuit is very short and is advantageous for a speaker having a long diameter in the length direction. (6) A magnetic shield type speaker and a magnetic circuit can be easily obtained.

[Procedure amendment 10]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ikuo Shinohara 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term in Sony Corporation (reference) 5D012 AA03 BB09 BD09 CA09 EA03 EA06 FA08 GA01 HA01

Claims (4)

[Claims] 1. A center yoke, a substantially rectangular first plate having a plurality of columnar magnets juxtaposed in one direction of the center yoke, and a through hole serving as a magnetic gap through which an outer periphery of the center yoke passes. A magnetic circuit comprising: a substantially rectangular second plate to which the other of the plurality of magnets is joined; and a box-shaped yoke surrounding the second plate. 2. The magnetic circuit according to claim 1, wherein the second plate is formed as the box-shaped yoke. 3. The magnetic circuit according to claim 1, wherein the plurality of magnets are arranged in parallel on an upper surface or a lower surface of the first plate. 4. A loudspeaker having a vibration system driven by a voice coil swingably mounted in a magnetic gap formed between a center yoke and a hole formed in a plate, wherein the loudspeaker is offset from the center of the center pole. A speaker comprising a magnetic circuit having a plurality of columnar magnets arranged in different directions.