JPH09284893A - Speaker equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain excellent acoustic reproduction by forming a nearly enclosed space between 1st and 2nd diaphragms fitted overlappingly to a coil bobbin so as to prevent split vibration of the diaphragms without components having a large size and a heavy weight. SOLUTION: A coil bobbin 6 is fitted with a voice coil 7 and the voice coil 7 is supported in a moving enable way while located in a magnetic gap. A 1st diaphragm 5a and a 2nd diaphragm 5b are supported by the coil bobbin 6. The 1st and 2nd diaphragms 5a, 5b are arranged close to each other and a nearly enclosed space is formed between them. Since stiffness of air layer in the enclosed space between the diaphragms 5a, 5b is very high (nearly one hundred and several tens of thousands (N/M)), the diaphragms 5a, 5b are damped to prevent split vibration of the diaphragms 5a, 5b. The stiffness in this speaker box is nearly several hundreds (N/M).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a speaker device for converting an electric signal into sound.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a voice coil 107 having a magnetic circuit and attached to a movably supported diaphragm 105 is arranged in a magnetic gap 114 of the magnetic circuit. Speaker devices have been proposed. In this speaker device, the voice coil 1
07 is converted into sound generated by the vibration of the diaphragm 105.

In such a speaker device, the voice coil 107 moves along with the diaphragm 105 in the magnetic flux in the magnetic gap 114 by being supplied with an electric signal. 105 is vibrated. The driving force for vibrating the diaphragm 105 is F, the magnetic flux density in the magnetic gap 114 is B, the current flowing through the voice coil 107 is I, and the length of the wire of the voice coil 107 is L. Then, F = IBL holds.

The magnetic circuit of this speaker device is
The yoke 102 has a substantially disk-like shape made of a magnetic material and has an annular driving magnet 103 attached to the front surface thereof. At the center of the front surface of the yoke 102, a columnar center pole portion 101 protrudes coaxially with the drive magnet 103. On the front surface of the drive magnet 103, a plate 104 formed of a magnetic material and formed in a disk shape having a through hole in the center is attached. The through hole of the plate 104 and the front end portion of the center pole portion 101 face each other to form the magnetic gap portion 114.

[0005] A frame 108 for supporting the diaphragm 105 is attached to the front surface of the plate 104 to form a speaker device. The diaphragm 10
The voice coil 107 is mounted on the rear surface of the fifth through a cylindrical bobbin 106. The voice coil 107 is located in the magnetic gap 114.

The diaphragm 105 has a through hole at the center where the bobbin 106 is mounted, which is closed by a cap portion 112. The diaphragm 105 has a peripheral portion attached to a front end portion of the frame 108 by a gasket 115 via a peripheral edge member 113. The bobbin 106 is mounted on the frame 1
08 is supported via a damper 109.

[0007] The lead 110 from the voice coil 107 is connected to a terminal 111 provided on the frame 108.

As for the sound reproduction characteristic of this speaker device, as shown in FIG.
L (dB)) (a ₀ , a ₃₀ , a _{60 in} FIG. 5), impedance characteristic with respect to frequency (Imp (Ω)) (b in FIG. 5), second-order distortion characteristic with respect to frequency (Dist (%))
(C in FIG. 5), third-order distortion characteristic with respect to frequency (Dist
(%)) (D in FIG. 5), the sound pressure characteristic (a ₀ ) with respect to the frequency in the front of the speaker device,
The sound pressure characteristic with respect to frequency (a ₃₀ ) at a position ₃₀ ° from the front of the speaker device and the sound pressure characteristic with respect to frequency (a ₆₀ ) at a position ₆₀ ° from the front of the speaker device are different from each other.

[0009]

By the way, in the speaker device as described above, particularly in the case of being configured as a small-sized full-band speaker, the sound pressure characteristic with respect to the frequency in the front face of the speaker device and the front face of the speaker device The sound pressure characteristic with respect to the frequency at the moved place is different because the diaphragm 105 does not vibrate uniformly and causes division vibration.

When such divisional vibration occurs, the reproduction characteristics and reproduction sound quality of the speaker device deteriorate. Such divided vibration can be suppressed by increasing the rigidity of the diaphragm, but it cannot be said to be sufficient suppression. Further, if an attempt is made to increase the rigidity of the diaphragm, the weight of the diaphragm is increased, and good sound reproduction cannot be performed.

Therefore, the present invention is proposed in view of the above-mentioned circumstances, and the division vibration of the diaphragm is prevented and the good sound is produced without increasing the size and weight of the apparatus. An object of the present invention is to solve the problem of providing a speaker device capable of reproducing.

[0012]

In order to solve the above-mentioned problems, a speaker device according to the present invention is provided with a magnetic circuit having a magnetic gap portion, and a voice coil attached to the voice circuit, and the voice coil is positioned in the magnetic gap portion. A coil bobbin movably supported in a closed state, a first vibrating plate supported by the coil bobbin, and a second vibrating plate supported by the coil bobbin. They are arranged so as to form a substantially sealed space between them.

Further, according to the present invention, in the above speaker device, a spacer made of a buffer material is provided in a sealed space between the first and second diaphragms.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the speaker device according to the present invention comprises a magnetic circuit and a frame 8 supported on the magnetic circuit.

The magnetic circuit has a disk-shaped yoke 2 made of a magnetic material, and an annular magnet 3 fixedly arranged on the front surface of the yoke 2. This magnet 3 generates a magnetic flux in the thickness direction.
That is, the magnet is magnetized such that the front and rear surfaces become magnetic poles. In the center of the front surface of the yoke 2, a cylindrical center pole portion 1 is integrally protruded.
The magnet 3 is coaxial with the center pole portion 1. The center pole portion 1 is inserted into the central through hole portion of the magnet 3.

On the front surface of the magnet 3 is attached a top plate 4 made of a magnetic material and formed in a disk shape having a through hole in the central portion. This top plate 4
The front end portion of the center pole portion 1 is inserted through a through hole at the center of the center pole.

That is, when the top plate 4 is attached to the magnet 3, a gap guide is inserted between the outer peripheral surface of the center pole portion 1 and the inner peripheral surface of the through hole at the center of the top plate 4. While the top plate 4 is positioned with respect to the center pole portion 1, the top plate 4 is bonded to the magnet 3. Then, after the adhesive for bonding the top plate 4 to the magnet 3 is solidified,
By removing the gap guide, the top plate 4 is fixed while being positioned with respect to the center pole portion 1.

The inner peripheral surface of the through hole in the central portion of the top plate 4 and the outer peripheral surface of the center pole portion 1 in the middle thereof face each other to form a magnetic gap portion 14.

The frame 8 is formed of a material having sufficient rigidity such as metal into a cylindrical shape whose front end side is expanded in a substantially conical shape, and the rear end side portion is the top plate 4 described above.
It is fixed to the front part.

In the holding portion on the front end side of the frame 8, the peripheral portion of the first diaphragm 5b is provided with the first edge member 13b.
It is attached by the first gasket 15b via. Further, in the holding portion on the front end side of the frame 8, the peripheral portion of the second diaphragm 5a is provided with the second edge member 13a.
It is attached by the second gasket 15a. These gaskets 15b and 15a are respectively
It is a ring-shaped sheet of paper coated with an adhesive.

Each of the edge members 13b and 13a is formed so as to have flexibility and is displaceable in the front-rear direction. These edge members 13b and 13a are formed in an annular shape and have a shape that bulges in a cylindrical surface shape toward the front side (sound emission direction). These edge members 13b and 13a are made of paper, cloth, or rubber. These edge members 13b and 13a are overlapped with each other in the front-rear direction via a minute gap (for example, about 1 mm).

Each of the vibrating plates 5b and 5a is formed in a substantially conical shape, and has a through hole in the center. The coil bobbin 6 is fitted and attached to the through holes at the central portions of the diaphragms 5b and 5a. The coil bobbin 6 is formed in a cylindrical shape and supports the diaphragms 5b and 5a at the front end side portion. The front end of the coil bobbin 6 is closed by a cap 12.
These vibrating plates 5b and 5a have minute gaps (for example, 1 mm).
Degree), they are overlapped with each other in the front-back direction.

The respective vibrating plates 5b and 5a cooperate with the outer peripheral surface of the coil bobbin 6, the respective edge members 13b and 13a and the first gasket 15b between the vibrating plates 5b and 5a, and are substantially It forms a closed space. Although this closed space cannot be said to be a closed space in consideration of the air permeability of the paper making cone paper (thickness of about 0.15 mm to 0.2 mm) forming each of the vibrating plates 5b and 5a, these vibrating plates 5 cannot be called.
It is a closed space as long as the air permeability of b and 5a is ignored. Further, when the diaphragms 5b and 5a are made of a material having almost no air permeability such as rubber or plastic, the diaphragms 5b and 5a are substantially completely closed spaces.

It is desirable that the coil bobbin 6 has a high rigidity and a light weight. Therefore, this coil bobbin 6 is made of paper or cloth impregnated with epoxy resin,
It is desirable to form a synthetic resin material such as a glass-epoxy plate (a glass fiber material solidified with an epoxy resin) into a cylindrical shape. Further, the coil bobbin 6 may be formed of a metal plate, paper, or the like.

A voice coil 7 is adhered to the outer peripheral surface of the coil bobbin 6 on the rear end side. The voice coil 7 is wound into a cylindrical shape and has lead wires at the beginning and end of winding. These lead wires are soldered to the tinsel wire 10 and are connected to the input terminal 11 provided on the frame 8 via a supporting member via the tinsel wire 10.

The voice coil 7 is located in the magnetic gap portion 14. That is, the voice coil 7 is coaxial with the center pole portion 1, and the center pole portion 1 and the top plate 4 are arranged.
And between the inner surface of the through hole at the center of the hole.

That is, when the coil bobbin 6 to which the voice coil 7 is attached is attached to the diaphragm 5, a voice coil spacer is inserted between the outer peripheral surface of the center pole portion 1 and the inner peripheral surface of the coil bobbin 6. Then, with the coil bobbin 6 positioned with respect to the center pole portion 1, the coil bobbin 6 is bonded to the diaphragm 5. Then, after the adhesive for bonding the coil bobbin 6 to the diaphragm 5 is solidified, the voice coil spacer is removed.
The coil bobbin 6 is fixed while being positioned with respect to the center pole portion 1.

The front end portion of the coil bobbin 6 is provided with a damper 9 having flexibility and vibration absorption,
The frame 8 is suspended by a rear end portion thereof so as to be movable in the front-rear direction.

The damper 9 is formed of a material such as cloth or paper in a substantially disc shape having a plurality of concentric bent portions (corrugation portions) serving as displacement portions, and a circular through hole is formed in the central portion. have. This damper 9 suspends the coil bobbin 6 by joining the outer peripheral surface of the coil bobbin 6 to the inner peripheral edge of the central through hole and attaching the outer peripheral edge to the frame 8.

In the speaker device according to the present invention configured as described above, an electric signal is supplied as a drive current to the voice coil 7 via the input terminal 11, whereby the coil bobbin 6 is moved to the center pole. The diaphragm 5 is driven in the axial direction of the unit 1 to vibrate, and sound is reproduced.

In this speaker device, since the stiffness of the air layer in the enclosed space between the diaphragms 5b and 5a is very large (for example, about several ten thousand (N / M)), the diaphragms are not provided. 5b and 5a are braked, and the respective vibration plates 5
The divided vibration of b and 5a is prevented. The air stiffness in the speaker box to which this speaker device is attached is about several hundred (N / M).

When air leaks from the main surface portions of the diaphragms 5b and 5a, the resistance of the air passing through the diaphragms 5b and 5a in this way also causes the leakage of air. The diaphragms 5b and 5a are braked, and the respective diaphragms 5b
The divided vibration of b and 5a is prevented.

As for the sound reproduction characteristics of this speaker device, as shown in FIG.
L (dB)) (A in FIG. 3), impedance characteristic with respect to frequency (Imp (Ω)) (B in FIG. 3), second-order distortion characteristic with respect to frequency (Dist (%)) (C in FIG. 3) ,
When the third-order distortion characteristic with respect to frequency (Dist (%)) (D in FIG. 3) is measured, the sound pressure characteristic with respect to frequency in the middle-high frequency band is smooth.

Since the two vibrating plates 5b and 5a are driven simultaneously, in terms of sound pressure characteristics,
It is desirable to reduce the weight per sheet as much as possible. Further, it is desirable that the diaphragms 5b and 5a are not in contact with each other. Therefore, a spacer made of a buffer material (for example, urethane foam) may be provided in the closed space between the diaphragms 5b and 5a.

Further, in this speaker device, the edge members 13b and 13a are brought close to each other, and the stiffness of the air between the edge members 13b and 13a causes the edge members 13b and 13a.
The divided vibration of is also suppressed. In addition, each of the edge members 13
When b and 13a are symmetrical with respect to each other in the front-rear direction, the non-linearities of the edge members 13b and 13a cancel each other out, so that the non-linear distortion can be suppressed.

As shown in FIG. 2, this speaker device has the first diaphragm 5b and the second diaphragm 5a.
May have different shapes, and the first edge member 13b and the second edge member 13a may have different shapes.

[0038]

As described above, in the speaker device according to the present invention, the space between the first and second diaphragms 5a and 5b mounted on the coil bobbin so as to overlap each other is a substantially sealed space. Therefore, the stiffness of the air in this space prevents the divided vibrations of the diaphragms 5a and 5b.

That is, the present invention can provide a speaker device in which division vibration of the diaphragm is prevented and good sound reproduction can be performed without causing an increase in size and weight of the device structure. It is possible.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a speaker device according to the present invention.

FIG. 2 is a longitudinal sectional view showing another example of the configuration of the speaker device according to the present invention.

FIG. 3 shows frequency-sound pressure characteristics, frequency-impedance characteristics, frequency-second-order distortion characteristics, frequency-of the above speaker device.
It is a graph which shows a 3rd-order distortion characteristic.

FIG. 4 is a vertical sectional view showing a configuration of a conventional speaker device.

FIG. 5 is a graph showing frequency-sound pressure characteristics, frequency-impedance characteristics, frequency-second order distortion characteristics, and frequency-third order distortion characteristics of a conventional speaker device.

[Explanation of symbols]

1 Center pole, 2 yokes, 3 magnets,
4 top plate, 5 diaphragm, 6 coil bobbin,
7 voice coil, 8 frame, 14 magnetic gap

Claims (2)

[Claims] 1. A magnetic circuit having a magnetic gap portion, a voice coil attached, a coil bobbin movably supported with the voice coil positioned in the magnetic gap portion, and a coil bobbin supported by the coil bobbin. 1 diaphragm and a 2nd diaphragm supported by the said coil bobbin, each said diaphragm is arrange | positioned in close proximity to each other, and the substantially sealed space is formed between each other. The speaker device that was made to exist. 2. The speaker device according to claim 1, wherein a spacer made of a cushioning material is provided in a sealed space between the first and second diaphragms.