JPH11215592A - Loudspeaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a loudspeaker with a simple structure and a high driving force by increasing magnetic flux interlinked with a voice coil placed in a magnetic air gap of a magnetic circuit. SOLUTION: A ring-shaped inner magnet 5 is placed inside a ring-shaped outer magnet 3 which is a component of a magnetic circuit, and one or two plates 1 and/or 6, each having a center hole are placed close to each other on an upper face of inner/outer magnets 5, 3, and one voice coil 8a is placed in a magnetic air gap 17 formed between an outer diameter of a center pole 4a and an inner diameter of the center hole of the plates 1 and/or 6 finally to configure a loudspeaker.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker capable of increasing the driving force of a cone in a magnetic circuit having a limited size, and more particularly to a loudspeaker capable of increasing a magnetomotive force in a magnetic gap of a magnetic circuit. It relates to improvement of speakers.

[0002]

2. Description of the Related Art Hitherto, various types of loudspeakers have been proposed in which a magnetomotive force in a magnetic gap of a magnetic circuit is increased. The applicant of the present invention has previously proposed a loudspeaker in which a strong magnetomotive force is obtained by a magnetic flux linked in a magnetic gap of such a magnetic circuit. Hereinafter, this speaker will be described in detail with reference to FIG.

FIG. 4 is a side sectional view taken along a diameter direction passing through the center of the opening when viewed from the plane of the small speaker. The yoke 4 of the speaker 20 is a disk made of a plate material such as pure iron. A cylindrical center pole 4a erected at the center of the disk-shaped part;
A magnet guide portion 4b is integrally formed with a stepped portion formed in a disc-shaped portion concentrically with a.

On the above-mentioned disk-shaped portion of the yoke 4, N.I. S and the magnetized or non-magnetized ring-shaped outer magnet 3 are bonded via an adhesive. The inner diameter of the ring-shaped outer magnet 3 is fitted and positioned in the step portion of the magnet guide portion 4b formed in the disk-shaped portion of the yoke 4.

In a general small loudspeaker 20, the width W between the outer diameter of the center pole 4a and the inner diameter of the outer magnet 3 is considerably large, and forms a substantially cylindrical space portion 18.

Therefore, in the speaker 20, the inner magnet 5 is disposed in the space 18 formed in the inner diameter of the center pole 4a and the outer magnet 3.

[0007] The inner magnet 5 has a thickness of N.M. in the thickness direction of a samarium-cobalt magnet or a neodymium magnet. S is formed into a ring shape magnetized or non-magnetized.
Is bonded via an adhesive on the stepped portion.

Next, a cylindrical gap guide (not shown) having a thickness of a gap width is inserted into the outer diameter of the center pole 4a, and adhesive is applied to the upper surfaces of the inner and outer magnets 5 and 3, respectively. Then, the inner diameter of the through hole formed in the second plate 6 and the first plate 1 is inserted into the outer diameter of the gap guide, and the second and first plates 6 and 1 are placed on the upper surfaces of the magnets 5 and 3, respectively. Join.

A funnel-shaped frame 7 made of steel or the like is fixed on the first plate 1 in advance with a stud or the like, or is screwed onto the first plate 1 via a screw or the like. The metal part of the magnetic circuit is completed.

The above-described gap guide is connected to the center pole 4a.
After being removed from the space, a spacer is inserted into the inner periphery of the voice coil bobbin 8, and the voice coils 8a and 11 (or the short coil) are set so as to be at predetermined positions in the first and second magnetic gaps 17 and 19, The voice coil bobbin 8 and the spacer are inserted from the tip of the center pole 4a.

Next, a corrugated damper 9 is joined between the outer periphery of the voice coil bobbin 8 and the bottom of the frame 7. In addition, the length of the voice coil bobbin 8 is increased by a predetermined length, and the end of the voice coil bobbin 8 extends at least to the lower surface from the second magnetic gap 19 in the space 18.

Further, the inner diameter of the funnel-shaped cone 10 having an edge 13 made of paper or the like is joined to the upper outer diameter of the voice coil bobbin 8, and the maximum diameter of the cone 10 is connected to the frame 7.
Is fixed to the peripheral edge of the upper opening via an arrow paper 12, and after removing the spacer inserted into the inner periphery of the voice coil bobbin 8, a cap 14 for preventing dust intrusion is adhered to the upper end of the voice coil bobbin 8. Kinshi wire 16 is voice coil 8a
And the input terminal 15 attached to the frame 7
The audio signal is supplied to the voice coils 8a and 11 via.

In addition, the magnets 3 on the outside and inside of the magnetized non-magnetized
When 5 and 5 are used, the magnets are magnetized in the same direction when the bonding of the adhesive is completed.

According to the speaker having the above-described structure, the voice coil 8 in the first magnetic gap 17 and the second magnetic gap 19 is formed.
If a and 11 are connected in series or in parallel, the cone 10
Obtains the induced force generated by the magnetic flux linking in the two magnetic paths of the first and second magnetic gaps 17 and 19, so that a loudspeaker emitting high sound quality and strong radiation by the added driving force can be obtained. . Further, when the voice coil 11 wound around the voice coil bobbin 8 is formed of a conductor, for example, a copper short ring, a braking force can be applied to the short ring 15. A small loudspeaker which can change the acoustic impedance of the vibration system of the above and can dump Q at the time of resonance particularly at a low-band resonance frequency is obtained.

[0015]

According to the above-described conventional loudspeaker, the voice coil bobbin 8 extends further downward from the first magnetic gap 17, so that the thickness of the outer ring-shaped magnet is large. Not only hinder miniaturization, but also the mass of the vibration system [the voice coil and the first
And the mass of the second voice coils 8a and 11 (short coil)], the damper 9 needs to have a double structure, and it is necessary to wind two voice coils around one voice coil bobbin. Is complicated.

Furthermore, even if a magnet having a large product (energy product) of the residual magnetic flux B and the coercive force H is used by using two magnets, magnetic saturation occurs at the yoke and the center pole portion, and a magnetic flux corresponding to the energy product is generated. There is a problem that it cannot be generated in the magnetic gap.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a speaker capable of radiating high sound quality and powerful, particularly suitable for a small speaker. It is an object of the present invention to provide a speaker which can be easily manufactured using one voice coil by increasing the magnetic flux intersecting the magnetic field and increasing the magnetic force.

[0018]

A speaker according to the present invention comprises: a first ring-shaped magnet forming a magnetic circuit;
A second ring-shaped magnet is arranged on the yoke between the center poles erected on the yoke, and one or two plates having the same inner diameter are arranged on the first and second ring-shaped magnets. Then, one magnetic gap is formed between the inner diameter of the one or two plates and the outer diameter of the center pole, and one voice coil for driving force is formed in this one magnetic gap. It is arranged.

According to the present invention, it is possible to obtain a loudspeaker capable of increasing the magnetomotive force of the magnetic gap without making the center pole thin.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a speaker according to the present invention will be described below in detail with reference to FIGS. The same parts as those in FIG. 4 are denoted by the same reference numerals, and redundant description will be omitted. FIG. 1 is a cross-sectional side view taken along a diameter direction passing through a center portion of an opening when viewed from a plane of a speaker showing one embodiment of the present invention;
FIG. 2 is a side sectional view of another similar loudspeaker, and FIG. 3 is a side sectional view of another similar loudspeaker.

In FIGS. 1 and 2, the difference in configuration from FIG. 4 is that the thickness T ₁ of the outer magnet 3 is small.
A 10 mm thick ferrite magnet is selected.

Further, on a first step portion comprising a first magnet guide 4b fitted to the inner diameter of the outer magnet 3 formed concentrically with the center pole 4a of the yoke 4 formed in the disk-shaped portion, A second step is formed from a second magnet guide 4c fitted with the inner diameter of the magnet 5, and a center pole 4a is formed at a center position on the second step.
Has been planted.

The first and second magnet guides 4
b and 4c are the first and second outer and inner magnets 3
By selecting thicknesses T ₃ and T ₄ that are sufficiently large so that the joint area of the step portion that fits with the inner diameter of 5 and 5 is large,
The yoke 4 and the first and second magnets 3 and 5 have a large energy product from the lower surface (S pole side) of the outer and inner magnets 3 and 5.
Further, a large amount of interlinkage magnetic flux can be given to the magnetic gap 17 without saturating the magnetic flux flowing into the center pole through the steps of the second magnet guides 4b and 4c.

In the present embodiment, the thickness T ₂ of the second magnet guide 5 is selected to be about 6 mm, an adhesive is applied to the upper surface of the inner magnet 5, and a through hole whose center hole is larger than the diameter of the center pole 4 a is formed. The disc-shaped second plate 6 is joined to the inner magnet 5 via a gap guide (not shown).

Similarly, an adhesive is applied to the upper surface of the outer magnet 3, and the disc-shaped first plate 3 having the same through-hole as the second plate 6 is attached to the outer diameter of the gap guide by the first diameter.
The inner diameter of the through hole of the plate is inserted, and the plate is joined to the outer magnet 1.

In this case, the lower surface of the first plate 1 and the second plate
The gap between the upper surfaces of the plates 6 is set to a value close to about 1 to 2 mm. Therefore, the magnetic gap 17 formed between the inner diameter of the through hole of the first plate 1 and the outer diameter of the center pole 4a has the first plate 1 → the N pole of the outer magnet 3 →
The magnetic flux indicated by φ ₁ interlinks the S pole of the outer magnet 3 → the upper surface portion outside the yoke 4 and the step portion of the first magnet guide 4 b → the yoke 4 → the center pole 4 a → the magnetic path of the magnetic gap 17. The driving force is generated by the voice coil 8a swinging up and down in the magnetic gap 17.

Similarly, the magnetic gap 17 provided in the second plate 6 disposed close to the first plate 1 is provided in the magnetic gap 17 of the second plate 6 → N pole of the inner magnet 5 → S The magnetic flux indicated by φ ₂ interlinks the magnetic path of the pole → the middle upper surface portion of the yoke 4 and the step portion of the second magnet guide 4 c → the yoke 4 → the center pole 4a → the magnetic gap 17; A driving force is generated by the magnetomotive force obtained by adding the magnetic flux φ ₁ + φ ₂ by the voice coil 8 a swinging up and down in the inside.

Accordingly, only one voice coil 8a of this embodiment is wound around the voice coil bobbin 8, and it is not necessary to wind two voice coils as shown in FIG. A magnet with a large energy product can be used for a small size.

Frame 7 and cone 10 and damper 9
Can be configured the same as in FIG.

In the case of FIG. 2, the loudspeaker shown in FIG. 1 is a magnetic shield type.
→ The ring-shaped cancel magnet 21 magnetized with N is joined via an adhesive or the like, and the bottom surface of the shield cover 22 made of a conductor or the like formed into a substantially bottomed cylindrical shape is joined to the N pole side of the cancel magnet 21. In addition, by joining the rising portion of the shield cover 22 to the outer periphery of the first plate 1, it is possible to easily provide a magnetically shielded speaker and to further increase the magnetic flux φ ₁ in the magnetic gap 17. Become.

FIG. 3 shows still another configuration of the loudspeaker of the present invention, and only differences from FIGS. 1 and 2 will be described in detail below.

In FIG. 3, the outer diameter of the ring-shaped outer magnet 3 is 70 mmφ, the inner diameter is 32 mmφ, and the thickness T _{1 is} 10 m.
m, the outer diameter of the inner magnet 5 is 32 mmφ, the inner diameter is 18 mmφ, and the thickness T ₁ = T ₂ = 10 mm.
₁ = T ₂ , the distance between the first plate 1 and the second plate 6 in FIGS. 1 and 2 is set to zero, the second plate 6 is omitted, and the outer and inner magnets 3 and 5 First
By joining the plate 1 only, thicker diameter D ₁ of the base portion of the second magnet guide 4c, taking enough height H, a case taken increase the contact area between the inner magnet 5.

When strontium ferrite is used as the outer and inner magnets 3, 1400 is used.
A magnetic flux of about 0 Gauss could be obtained.

In the conventional configuration shown in FIG. 4, the center pole 4a is substantially straight, and the magnet guide 4b is merely used as a guide for joining the outer magnet 3 onto the yoke 4, so that the limit is 11500 gauss. Was. This is because even if the energy products of the inner and outer magnets 5 and 3 are increased, magnetic saturation occurs at the step of the magnet guide. In the above embodiment, the volume of the inner magnet 5 is approximately 18% of the volume of the outer magnet 1.
It corresponds to.

That is, in FIG. 3, there is only one magnetic gap 17 formed between the inner diameter of the first plate 1 and the outer diameter of the center pole 4a. This magnetic gap is extremely narrow, so that the thin flow resistance in the magnetic gap is reduced. Indicates a large value.

When the inner and outer magnets have the same dimensions as described above, and the inner magnet 5 of the speaker shown in FIG. 1 is a magnet having a high energy product such as samarium, cobalt or neodymium, the magnetomotive force is substantially close. flux phi ₁ and phi ₂ of the two gaps arranged is summed, because they act on a single voice coil 8a 11500 Gauss +
A strong magnetic flux of 13000 gauss = 24500 gauss could be obtained.

[0037]

According to the loudspeaker of the present invention, the magnetic fluxes of the outer and inner magnets are added to one voice coil, and a stronger magnetic flux is provided in the magnetic air gap, so that the driving force of the loudspeaker can be increased. . Further, since the magnetic gap is formed narrow and the thin flow resistance due to a thin fluid which voice coil is subjected increases, that the magnetic flux can be reduced in the resonance sharpness Q ₁ to the lowest resonance frequency of the loudspeaker The Q can be made smaller by both actions of the increase and the sound quality of the small speaker can be improved and the size can be reduced. In addition, since only one voice coil needs to be wound around the voice coil bobbin structurally, a simple configuration can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a speaker of the present invention.

FIG. 2 is a sectional view of another speaker of the present invention.

FIG. 3 is a sectional view of still another speaker of the present invention.

FIG. 4 is a cross-sectional view of a conventional speaker.

[Explanation of symbols]

1,6 mm plate, 3 mm outer magnet, 4 mm
Center pole, 5 mm inner magnet, 8 mm voice coil bobbin, 8a voice coil, 17, 19 mm magnetic gap, 18 mm space

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akihiro Akiyama 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Kenji Tokushige 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (3)

[Claims] A second ring-shaped magnet is provided on a yoke between an inner diameter of a first ring-shaped magnet forming a magnetic circuit and a center pole erected on a yoke, and the first and second ring-shaped magnets are provided. One or two plates having the same inner diameter are disposed on the ring-shaped magnet, and one or two plates having the same inner diameter are located close to each other between the inner diameter of the one or two plates and the outer diameter of the center pole.
A speaker comprising: two magnetic gaps; and one drive coil disposed in the one magnetic gap. 2. A step for fitting an inner diameter of first and second ring-shaped magnets to the center pole,
2. The speaker according to claim 1, wherein a contact surface in a height direction between the second ring-shaped magnet and the step is increased. 3. The speaker according to claim 1, wherein the second ring-shaped magnet is a magnet having a large energy product, such as a neodymium magnet.