JP2000078689A - Electroacoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroacoustic transducer that is thin and capable of reproducing sound over a wide band where no high-cut filter for a network is required in the case of obtaining a coaxial speaker unit or a coaxial headphone unit. SOLUTION: A diaphragm 17 is placed behind a frame 14 or a flange part 12a, a double outer magnet type magnetic circuit and an inner magnet type magnetic circuit are placed coaxially in front of the frame 14 or the flange 12a, a diaphragm 9 for a high frequency sound is provided to the outer magnet type magnetic circuit, the inner magnet type magnetic circuit drives the diaphragm 17 behind the frame 14 or the flange part 12a to be able to sum the magnetomotive forces of the magnets of the inner/outer magnetic circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electro-acoustic converter suitable for use in a small speaker device or headphone device, and more particularly to a coaxial type having high sound quality and high sensitivity having a wide reproduction band from a high frequency range to a low frequency range. The present invention relates to a small electric / acoustic conversion device.

[0002]

2. Description of the Related Art Conventionally, coaxial speaker units have been widely used because high-, low-, and mid-range sound sources can be emitted from the same location. A low-pitched speaker unit is assembled, and a separately assembled high-pitched tweeter is coaxially arranged approximately at the center of the diaphragm of the low-pitched speaker unit. Since the magnetic circuit and the magnetic circuit of the loudspeaker unit are provided independently, the coaxial type speaker unit has a large depth, and even when it is put into a speaker box or the like, it is difficult to reduce the size.

In particular, a case where a coaxial type speaker device in which a speaker unit having a diameter of about 65 mmφ and a book shell type speaker box is used to emit middle to low to high sounds with high sensitivity without deteriorating sound quality is obtained. However, since the magnet used in the magnetic circuit is small and a strong magnet cannot be used, it is difficult to reproduce with good sound quality over a wide reproduction band.

In the case where reproduction is performed over a wide frequency band using a network system, a high-frequency cutoff filter (high cut filter) using a choke coil or the like is conventionally used to determine a crossover point. Therefore, there is a problem such as an increase in the impedance of the speaker voice coil.

An object of the present invention is to provide an electro-acoustic conversion device such as a speaker device or a headphone device which has solved the above-mentioned problems. It is an object of the present invention to obtain an electro-acoustic converter with good sound quality and high sensitivity from middle to low to high tones.

[0006]

According to the electro-acoustic converter of the present invention, a magnetic circuit is arranged in front of a funnel-shaped frame, and a vibration for middle and low sounds is surrounded by the frame behind the frame. A plate is arranged, and a diaphragm for high sound is coaxially arranged in front of the magnetic circuit, and the sound from the diaphragm for middle and low sound is emitted forward through the opening in the frame. It is.

According to the electro-acoustic converter of the present invention, a dome-shaped high-frequency sound diaphragm is arranged in the magnetic gap of the two external magnet type magnetic circuits formed in front of the frame. An inner-magnet-type magnetic circuit is configured on the back side of the magnetic-type magnetic circuit, and this inner-magnet-type magnetic circuit is fixed to the frame, and a diaphragm for middle and low-frequency sounds is arranged behind the frame. A coaxial type conversion means having a diaphragm and a treble diaphragm can be configured, and a high cut filter can be configured by a magnetic circuit placed in front of the middle and low frequency diaphragm, eliminating the need to use an electrical high cut filter. In addition, the center of the sound source from the bass to the treble can be easily adjusted, and a device suitable for a small-sized electro-acoustic converter can be obtained.

Further, according to the present invention, the magnetic flux of the magnet of the inner magnetic circuit is added to the magnets of the two outer magnetic circuits, so that the electric / acoustic conversion means for high and middle / low sounds can be provided with a stronger magnetic flux. Thus, an electro-acoustic conversion device that can be driven by the above-described method can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a speaker, a speaker device, a headphone unit and a headphone device as an electric / acoustic converter of the present invention will be described in detail with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a coaxial type speaker unit as a whole. It is arranged.

First, description will be made from the configuration of the tweeter 2.
The magnetic circuit of the tweeter 2 is of an outer magnet type, and the first yoke 4 is formed in a substantially disk shape, and its cross section is substantially reversed by a conductive metal having a columnar center pole 4a erected at the center of the disk. It is molded integrally so as to form a T shape.

The first magnet 6 is formed in a ring shape and is fixed on the disk of the first yoke 4 via an adhesive. The magnet 6 may be magnetized in advance in the thickness direction with, for example, NS, but may be magnetized after the tweeter 2 is assembled.

An adhesive is applied to the upper surface of the ring-shaped magnet 6 to form a plate 7 made of a ring-shaped conductive metal.
To join. At this time, a jig is inserted into the center pole 4a, and the plate 7 is fixed so that the first magnetic gap 8 formed between the inner diameter of the plate 7 and the center pole 4a has a constant interval.

The outer diameter of the plate 7 is selected to be larger than the outer diameter of the first yoke 4, and has an outer diameter substantially equal to the outer diameter of the plate 7, and the inner diameter is the outer diameter of the first magnet 6. An outer magnet type ring-shaped second magnet 6a having a larger inner diameter is joined to the lower side of the plate 7 along the outer periphery of the plate 7 with an adhesive or the like. In this case, the second magnet 6a
Is magnetized with S · N in the thickness direction opposite to the first magnet 6.

Next, a voice coil 10 for a tweeter is inserted into the magnetic gap 8. The diaphragm 9 and the voice coil bobbin 9a are integrally formed, and the voice coil 10 is wound around the voice coil bobbin 9a. ing.

The diaphragm 9 is integrated with the edge 9b, and is formed using, for example, a polyester film or the like.

The voice coil 10 wound around the voice coil bobbin 9a is inserted into the magnetic gap 8, and the outer periphery of the edge portion 9b is fixed on the plate 7 with an adhesive or the like. It is pivotally mounted so that it can swing up and down.

A cylindrical third magnet 11 serving as an inner magnetic circuit for the squawker 3 is bonded and fixed to the lower side of the yoke 4 of the tweeter 2 assembled as described above via an adhesive. This magnet 11 is magnetized in advance with N · S in the thickness direction, and is joined to the lower surface of the first yoke 4 so that the center position of the center pole 4a and the center position of the third magnet 11 coincide. .

Next, a second yoke 12 made of a substantially funnel-shaped (or dish-shaped) conductive metal is prepared. The second yoke 12 has a flange portion 12a on the upper side, and one through hole 12c is formed around the center of the bottom surface portion 12b.

The flange portion 1 of such a second yoke 12
When joining the second magnet 2a to the lower surface of the second magnet 6a via an adhesive, a gap guide is inserted into the outer periphery of the third magnet 11, and the through hole of the second yoke 12 is formed in the outer diameter of the gap guide. The second magnetic gap 13 having a predetermined gap is formed between the outer diameter of the cylindrical third magnet 11 and the inner diameter of the through hole 12c formed in the bottom surface 12b of the second yoke 12 by inserting and joining the second magnet 12c. By forming, the inner-magnet type magnetic circuit portion of the squawker 3 for middle and low frequency is completed.

Next, the bottom surface 12b of the second yoke 12 is placed on the inner surface of the bottom of the metal frame 14 formed in a substantially funnel shape, and is fixed with rivets or the like.

Next, the gap guide is inserted into the cylindrical magnet 11, and the voice coil bobbin 15 around which the voice coil 5 for the squawker 3 is wound is inserted outside the cap guide.

Next, the inner diameter of a ring-shaped normal damper 16 having a corrugated corrugation is joined to a substantially middle position of the voice coil bobbin 15, and the outer diameter of the damper 16 is adjusted to the vicinity of the outer periphery on the back side of the bottom of the frame 14. To hold the voice coil 5 swingably in the up-down direction.

Next, the inner diameter portion of the diaphragm 17 having a parabolic cone shape is joined to the lower end portion of the voice coil bobbin 15.

The diaphragm 17 may be a fixed edge integrated with the edge 18 or a configuration in which a ring-shaped edge having a small convex portion is joined to an outer peripheral portion of a parabolic cone-shaped diaphragm.

The outermost peripheral portion of the edge 18 is joined to the outermost diameter portion of the frame 14 via arrow paper 19.

When the joining and drying of the damper 16 and the diaphragm 17 are completed, the gap guide is removed and the cap 20 is covered on the lower end of the voice coil bobbin 15 and joined.

The cap 20 is concave so as to reduce the depth of the entire speaker unit 1. Further, the frame 14 is provided with a plurality of relatively large openings 14a in order to transmit the direction of sound emission from the diaphragm 17 at the rear of the frame 14 to the front (upward in FIG. 1).

In FIG. 1, the magnetization direction of the first magnet 6 is set to NS in the thickness direction of the magnet, the magnetization direction of the second magnet 6a is set to SN in the thickness direction of the magnet, Although the magnetization direction of the magnet 11 is set to N · S in the thickness direction of the magnet, as shown in FIG. 2, the magnetization directions of the second magnet 6a and the third magnet 11 are set to N · S in the thickness direction of the magnet, respectively. S and SN may be reversed from FIG. 2 is exactly the same as FIG. 1 except for the magnetizing direction of the magnet described above. Therefore, the same reference numerals are given to portions corresponding to FIG.

A speaker device in which the above-described speaker unit 1 is built in a speaker box 22 will be described with reference to a sectional side view of FIG.

The speaker box 22 is made of a synthetic resin such as ABS and is formed in a box shape integrally with the baffle plate 22a and the phase inversion type duct 23, and the back plate is formed of a substantially square plate.

The speaker unit 1 is fixed in a usual manner so as to face the speaker sound emission hole 24 formed above the baffle board 22a, and a phase inversion type speaker device 25 using a coaxial type speaker is constructed.

In the speaker unit 1 of this embodiment, one end of the lead wire taken out from the voice coil 5 for the squawker 3 and one end of the lead wire taken out from the voice coil 10 of the tweeter 2 are fixed to the frame 14 by insulating terminals 26a. And a lead wire 28 connected between the insulating terminal 26a and the insulating terminals 26a and 26a fixed to the frame 14.
Are connected to respective input terminals 27 and 27 fixed to the back plate. The sound signal is input to the squawker 3 and the tweeter 2 from the respective input terminals 27 and 27 in parallel. Of course, the acoustic signal may be supplied in series with one tweeter insulated terminal 26a and 26b.

According to the configuration of the speaker device as described above, the depth direction of the speaker unit 1 is extremely thin without projecting backward by the amount of the magnetic circuit, so that the depth of the speaker box 22 can be reduced, and a speaker suitable for a book shell type. The device can be provided. The magnetic circuit for the tweeter and the magnetic circuit for the squawker can add the magnetic flux of the magnetomotive force of one magnet to the magnetic flux of the magnetomotive force of the other magnet by appropriately selecting the magnetization direction as described later. Therefore, even a speaker unit having a small diameter can increase the magnetomotive force.

FIG. 4 shows another embodiment of the present invention, and is a sectional side view in the case where the electric / acoustic converter is used for the headphone unit 28 or the headphone device 29.

First, the structure of the headphone unit 28 will be described with reference to a side sectional view shown by a solid line in FIG. In the headphone unit 28 of FIG. 4, the magnetic circuit and the vibration system have exactly the same configuration as that described in FIG. 1 and FIG. 2, and are small enough to be able to abut the right and left ears. A dome-shaped protector 35 is held at the maximum outer diameter position of the frame 14 so as to surround the outer periphery of the diaphragm 17 for middle and low sounds, and a plurality of openings 36 are formed in the bottom surface of the protector 35 to form a resistance such as resistance paper. The headphone unit 28 is formed by attaching the body 37 so as to cover the opening 36.

The above configuration shows the configuration of the headphone unit 28. The headphone unit 28 is connected to the left and right headphone units 28 provided with the earpieces 42 and the casing 41 as shown by phantom lines by a headband. Thus, the headphone device 29 is formed.

It is assumed that the magnetic flux of the magnetic circuit of the magnetic circuit used in the electro-acoustic converter composed of the above-described speaker unit 1 and speaker device 25 and the headphone unit 28 and headphone device 29 is added to one magnetic path. This will be described in detail with reference to FIGS.

First, of the first to third magnets 6, 6a and 11 used in the magnetic circuit shown in FIGS. 1 and 3, the magnetic gap 8 between the outer magnet type magnet 6 and the center pole 4a is formed. The magnetic flux linked to the voice coil 10 for the tweeter 2 inserted into the
→ Voice coil 10 in magnetic gap 8 → Center pole 4
a → yoke 4 → drives the voice coil 10 by the closed circuit phi ₁ of S pole of the magnet 6, similarly interlinked to the voice coil 5 the diaphragm 17 is inserted into the magnetic gap 13 which is held for squawker The magnetic flux is the N pole of the third magnet 11 → the disk portion of the yoke 4 → the S pole of the first magnet 6 → the first pole.
N pole of magnet 6 → plate 7 → S pole of second magnet 6a → N pole of second magnet 6a → second yoke 12 → voice coil 5 for squawker in magnetic gap 13
→ S pole of the third magnet 11 → Third magnet 11
A magnetic flux closed circuit φ ₂ is generated like the N pole of FIG. In this case, the squawker diaphragm 17 is driven by a magnetic flux to which the magnetomotive force of the first magnet 6, the second magnet 6a, and the third magnet 11 is added, so that the squawker diaphragm 17 for middle and low frequency sounds. Sound quality can be improved.

Also, as shown in FIGS. 2 and 4, the magnetization directions of the second magnet 6a and the third magnet 11 are shown in FIGS.
Conversely, when N and S are magnetized in the thickness direction of each magnet, a closed circuit φ ₁ of the magnetic flux driving the voice coil 10 of the tweeter 2 and the first to third magnets 6, 6
The squawker 3 driven by the closed circuit φ ₂ of the magnetic flux to which the magnetomotive forces of the a and 11 are added (in this case, the direction of the magnetic flux is opposite to that in FIG. 1)
The voice coil 5, further by a closed circuit of the magnetic flux indicated by phi _3, the magnetomotive force of the tweeter 2 side can be increased.

That is, the N pole of the third magnet 11 → the voice coil 5 in the magnetic gap 13 → the second yoke 12 → the S pole of the second magnet 6a → the N pole of the second magnet 6a →
Plate 7 → Magnetic gap 8 in which voice coil 10 of tweeter 2 is inserted → Center pole 4 a → Disk portion of first yoke 4 → S pole of third magnet 11 → Magnetic flux indicated by N pole of third magnet 11 The tweeter 2 and the squawker 3 can further increase the magnetomotive force by the closed circuit φ ₃ through which the high frequency sound and the medium / low frequency sound can be reproduced.

Further, according to the electro-acoustic converter of this embodiment, since the magnetic circuit of the tweeter 2 and the magnetic circuit of the squawker 3 are coaxially provided on the front surface of the squawker diaphragm 17, the frequency characteristic curve of FIG. In the case of FIG. 30, the frequency greatly attenuates as shown by a curve 31 from the middle frequency f _M to the high frequency f _H.

Normally, when reproducing with high sensitivity and high sound quality over a wide band, the frequency of the crossover point is determined by connecting a high cut filter such as a choke coil in series to the speaker, and the frequency from the tweeter in the high frequency range is determined. Although the high-pitched sound is emitted as indicated by the curve 32, the impedance rises because the choke coil is connected in series to the voice coil of the speaker. In this case, the voice coil 5 for the squawker 3 and the diaphragm 9 of the tweeter 2 vibrate in one body, and the sound pressure level of the squawker 3 in the middle to high range has a magnetic circuit in front of the squawker diaphragm 17. Therefore, it attenuates sharply,
In this band, tweeter 2 is at a high level and tweeter 2
Since a high-frequency sound is radiated from the diaphragm 9 for high efficiency, a configuration that does not require a high-cut filter for a network can be achieved by appropriately selecting a crossover point.

Furthermore, since the magnetomotive force can be made very large,
Since the resonance sharpness (Q) at the lowest resonance frequency of the electro-acoustic converter can be reduced, bass reproduction can be easily performed even with a small speaker unit and a speaker device or a headphone unit and a headphone device.

[0045]

According to the present invention, the diaphragm of the tweeter is driven by the double outer magnetic type magnetic circuit, and the diaphragm (diaphragm) for the squawker (for middle and low frequency sounds) is driven by the inner magnetic type magnetic circuit. In the same way, a frame with an opening is provided in front of the squawk diaphragm (diaphragm), and the inner and outer magnetic circuits are coaxially arranged on the front surface of the diaphragm, so that the depth direction of the speaker unit, headphone unit, etc. is greatly reduced. Thus, the depth of the speaker device or the headphone device can be reduced, and the magnetomotive force of the magnet of the magnetic circuit can be added to improve the sound quality of the high-range speaker unit or the headphone unit.

According to the present invention, the magnetic flux obtained by adding the magnetic fluxes of the first to third magnets to the first and second magnetic air gaps flows, so that the first or second magnetic air gap is generated. The magnetic force is increased, the sound quality is improved, and the resonance sharpness Q at the lowest resonance frequency of the diaphragm for middle and low sounds can be reduced, and the bass reproduction band can be easily expanded using a small speaker box.

Further, since the frame 14 and the magnetic circuit are provided on the front surface of the diaphragm 17 for the squawker 3, an electro-acoustic converter capable of reproducing with high sensitivity over a wide band without using an electric network can be obtained. Can be

[Brief description of the drawings]

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

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

FIG. 3 is a side sectional view of the speaker device of the present invention.

FIG. 4 is a side sectional view of the headphone unit of the present invention.

FIG. 5 is a frequency characteristic curve diagram for explaining the present invention.

[Explanation of symbols]

1 Speaker unit, 2 Loudspeaker (tweeter), 3 Loudspeaker (squawker), 6, 6
a, 11 ‥‥ magnet, 28 ‥‥ headphone unit, 29 ‥‥ headphone device

Continued on the front page (72) Inventor Ryo Yamagishi 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Naotaka Kadota 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Stock In-house F term (reference) 5D012 BB01 BB02 CA09 DA04 GA02

Claims (3)

[Claims] 1. A magnetic circuit is provided in front of a funnel-shaped frame, a diaphragm for middle and low sounds is provided behind the frame so as to surround the frame, and a treble sound is provided in front of the magnetic circuit. An acoustic-to-acoustic converter characterized in that a diaphragm for coaxial use is disposed coaxially, and sound from the diaphragm for middle and low sounds is emitted forward through an opening formed in the frame. . 2. The electric / acoustic converter according to claim 1, wherein a magnetic circuit disposed coaxially on the front surface of said middle / low-frequency sound diaphragm serves as high-frequency cutoff filtering means. 3. The electric / acoustic converter according to claim 1, wherein said electric / acoustic converting means comprising said high frequency and low frequency diaphragms is used for a speaker or a headphone.
Sound conversion device.