JP3271075B2 - Speaker unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker unit and, more particularly, to a sound absorbing process on the rear side of a diaphragm for preventing reverberation and vibration due to sound in the unit.

[0002]

2. Description of the Related Art In order to reproduce a faithful tone with a speaker device, it is required that there is no reverberation or vibration due to sound in the speaker device. In view of the above, conventionally, various types of sound absorbing materials provided in a speaker box or a back cavity of a speaker device have been proposed. This sound absorbing material is intended to prevent the sound emitted from the speaker unit from being reflected on the back plate or the like on the inner surface of the speaker box or the like, thereby preventing the reflected sound or resonance.

[0003] Further, the speaker unit itself attached to the speaker device also has a
In order to prevent a sound from being reflected on the magnetic circuit portion to generate a reflected sound or to cause the magnetic circuit itself to resonate, there is a type in which a sound absorbing material is provided in the magnetic circuit portion. As a sound absorbing material provided in the speaker unit, a soft sound absorbing material such as glass wool, cotton, or felt has been conventionally used.

[0004]

However, the sound pressure inside the speaker unit is high due to the vibration of the diaphragm.
The air velocity is fast. As a specific example, when a sound pressure of about 90 dB is obtained at a distance of 1 m from the front of the speaker device, the sound pressure on the back side of the diaphragm is 160 dB.
Therefore, when a sound absorbing material made of a soft material such as the above-mentioned conventional glass wool is disposed inside the speaker unit, the sound absorbing material itself is generated by sound pressure or air flow generated by driving the diaphragm. Was sometimes vibrated.

[0005] When the sound absorbing material provided in the speaker unit is vibrated by the sound pressure or the flow of air in the speaker unit, the fibers of the sound absorbing material rub against each other to generate unnecessary friction noise. In addition, the loss of the sound energy increases due to the vibration of the speaker unit itself. These phenomena are acoustically perceived by the listener as a noisy rising noise with a lot of noise.

Therefore, the present invention solves the above-mentioned problems, and provides a bright and clear sound with little noise by installing a strong sound absorbing material which does not vibrate even in an environment where a high sound pressure and a high air flow velocity in the speaker unit are high. An object of the present invention is to provide a speaker unit with a good start-up.

[0007]

According to the present invention, there is provided a speaker unit including at least a diaphragm to which a voice coil is attached, and a magnetic circuit unit having a magnet and a yoke. In the speaker unit, a porous hard sound absorbing material and a soft sound absorbing material having a sound absorbing effect of a frequency different from that of the sound absorbing material are superimposed on a member constituting the magnetic circuit portion on the back side of the diaphragm. And a sound absorbing member having a cross-sectional shape adapted to the shape of the diaphragm. Further, the speaker unit according to the present invention is a speaker unit including at least a diaphragm on which a voice coil is attached, and a magnetic circuit unit having a magnet and a center pole, wherein the center pole is a rear surface of the diaphragm. And a ventilation hole communicating with the outside of the speaker unit, and a porous hard acoustic material formed in a ring shape in accordance with the ventilation hole is attached to a tip end surface of the center pole. is there. Further, the speaker unit according to the present invention is a speaker unit including at least a diaphragm on which a voice coil is mounted, and a magnetic circuit unit having a magnet and a center pole, wherein the center pole is a rear surface of the diaphragm. And a ventilation hole communicating the outside of the speaker unit with the outside of the speaker unit, and closing an inner wall portion and an opening of the ventilation hole of the center pole.
In this case, a porous and hard sound absorbing material is attached.

As the porous and hard sound-absorbing material provided on the member constituting the magnetic circuit section on the back side of the vibration plate, a porous metal, a porous ceramic or the like may be used.

The magnetic circuit section of the speaker unit to which the present invention is applied can be used in either an external magnetic type or an internal magnetic type.

[0010]

According to the present invention, since a porous and hard sound absorbing material is attached to the member constituting the magnetic circuit portion on the back side of the diaphragm, the high sound pressure and the air flow rate in the speaker unit are reduced. Even under a fast environment, the sound absorbing material itself can be prevented from vibrating.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a case where the speaker unit 1 according to the present invention is applied to a unit having an external magnet type magnetic circuit unit.

The speaker unit 1 shown in FIG. 1 includes a magnetic circuit section 2, a diaphragm 3, and a support frame 4 for supporting the diaphragm 3 with respect to the magnetic circuit section 2. The magnetic circuit section 2 is configured as an external magnet type magnetic circuit, and is arranged on a yoke 6 having a center pole 5 at the center and on the yoke 6 around the center pole 5. A ring-shaped magnet 7 and a ring-shaped plate 8 mounted on the upper part of the magnet 7
And The magnetic circuit section 2 forms a magnetic circuit by the magnet 7, the center pole 5 of the yoke 6, and the plate 8, and has an inner opening side end face of the plate 8 and a tip outer peripheral face of the center pole 5. The magnetic flux of the magnet 7 is concentrated in a magnetic gap 9 provided between the magnets.

Next, the diaphragm 3 is formed as a hemispherical dome-shaped diaphragm, and a cylindrical voice coil bobbin 11 around which the voice coil 10 is wound is provided at the base end side.
Is installed. The voice coil 10 faces the inside of the magnetic gap 9 of the magnetic circuit section 2. Although not shown, the voice coil 10 is connected to an external connection terminal via, for example, a tinsel wire.

The edge 3a of the diaphragm 3 is
It is supported by the support frame 4. The speaker unit 1 configured as described above includes the voice coil 1
A driving force is generated in the voice coil 10 in the magnetic gap 9 by the signal current applied to 0, and the diaphragm 3 is vibrated to generate sound.

In the speaker unit 1 configured as described above, a sound absorbing material 12 is attached to the front end face 5a of the center pole 5 constituting the magnetic circuit section 2 so as to face the rear side of the diaphragm 3. . This sound absorbing material 12 is made of a porous and hard material. Specifically, a porous metal or a porous ceramic is used. Examples of the porous metal include Celmet (trade name) manufactured by Sumitomo Electric Industries, Ltd.

The means for attaching the sound absorbing material 12 to the tip end surface 5a of the center pole 5 may be any as long as the sound absorbing material 12 is fixedly attached to the tip end surface 5a of the center pole 5; Various fixing means such as stoppers can be used.

The rear side of the diaphragm 3 is an internal space A closed by the edge 3a of the diaphragm 3 and the magnetic circuit section 2. The distance between the magnetic circuit section 2 and the diaphragm 3 is short. Therefore, when the diaphragm 3 vibrates, the sound pressure in the closed internal space A becomes very high, and the flow velocity of the air also becomes high. However, the sound absorbing material 12 made of the porous and hard material is used.
The sound absorbing material 12 itself has a high sound absorbing power due to its porous nature, and can prevent the vibration of the sound absorbing material 12 itself due to the sound pressure and the flow of air due to its hard nature. Therefore, the sound absorbing material 12
Can exhibit excellent sound absorbing power even in an environment with a high sound pressure of the internal space A in the speaker unit 1 and a high flow velocity of air, generation of frictional sound and the like due to vibration of the sound absorbing material 12 and generation of sound energy. Loss can be prevented, and the speaker unit 1 can exhibit high-quality reproduction characteristics with low noise and a bright and clear start-up.

The sound absorbing material 12 is not only attached to the front end face 5a of the center pole 5, but also formed from the above material in a circumferential shape along the inner peripheral edge of the magnet 7 as shown by a broken line in FIG. The second sound absorbing member 14 may be arranged together.

FIGS. 2A and 2B show an example in which the shape of the sound absorbing material 12 provided on the front end face 5a of the center pole 5 is changed. FIG. 2A shows the sound absorbing material 12 formed in a circular arc shape in accordance with the dome shape of the diaphragm 3, and FIG. 2B shows the sound absorbing material 12 formed in a trapezoidal cross section. With such a shape, the sound absorbing material 12 can be disposed more on the distal end surface 5a of the center pole 5, and the sound absorbing effect can be enhanced.
The resistance to the flow of air generated by the vibration of the diaphragm 3 can be reduced.

As shown by broken lines in FIGS. 2 (a) and 2 (b), a conventional soft sound absorbing material 13 made of glass wool or felt is disposed above the sound absorbing material 12 so as to be superposed. And the conventional sound absorbing material 13 may be used together. Thus, by using different kinds of sound absorbing materials 12 and 13 together, sound absorbing effects of different frequencies can be exhibited. In particular, the soft sound absorbing material 13 can enhance a sound absorbing effect in a high-frequency range.

FIG. 3 shows the speaker unit 1 in which a vent hole 15 is provided in the center pole 5. The ventilation holes 15 are for sucking or discharging air between the internal space B of the speaker unit 1 formed by the diaphragm 3 and the magnetic circuit unit 2 and the outside of the unit, as indicated by an arrow x in the drawing. It is. That is, this vent 1
5 is to reduce the sound pressure of the internal space B of the speaker unit 1 by discharging air from the internal space B to the outside of the unit or by sucking air from the outside of the unit into the internal space B. It is for planning.

In this case, the porous hard sound absorbing material 12 disposed on the front end face 5a of the center pole 5 is used.
If a is formed in a ring shape according to the ventilation hole 15,
The sound to be reflected by the center pole 5 or the like can be absorbed by the sound absorbing material 12a without blocking the flow of the air.

Further, as shown in FIG. 4, a sound absorbing material made of the porous hard material may be attached to the inner wall portion of the ventilation hole 15. In this way, resonance in the ventilation hole 15 can be prevented.

The sound-absorbing material mounted in the ventilation hole 15 includes a first sound-absorbing material 16a formed in a cylindrical shape so as to be mounted on the inner wall of the cylindrical portion on the upper end side of the ventilation hole 15. The second sound absorbing material 1 formed in a conical shape so as to be attached to the inner wall of the conical portion on the lower end side of the pore 15.
6b, any one of the third sound absorbing members 16c formed in a disc shape so as to close the opening of the ventilation hole 15 may be attached in combination of two or more. At this time, the third sound absorbing material 16c is most effective in suppressing the vertical air column resonance in the vent hole 15.

Next, a case where the present invention is applied to a speaker unit 20 having an inner magnet type magnetic circuit will be described with reference to FIGS. The magnetic circuit portion 21 of the speaker unit 20 shown in FIG.
The magnet 23 is arranged inside the bottom of the yoke 22. On the upper end side of the magnet 23, a center pole 25 constituting a magnetic gap 24 is disposed so as to face the inner opening side end surface of the yoke 22. The magnetic circuit portion 21 forms a magnetic circuit by the magnet 23, the pot-shaped yoke 22, and the center pole 25, and has an inner opening side end face of the yoke 22 and a tip outer peripheral face of the center pole 25. The magnetic flux of the magnet 23 is concentrated on a magnetic gap 24 provided between the magnets.

In the loudspeaker unit 20 having the inner magnetic type magnetic circuit portion 21 constructed as described above, the diaphragm 26 is attached to the distal end surface 25a of the center pole 25 similarly to the outer magnetic type loudspeaker unit 1. If a sound absorbing material 27 made of a porous and hard material is attached to the rear side of the speaker unit, vibrations and the like of the sound absorbing material 27 are prevented as in the case of the external magnet type speaker unit 1, and high sound absorption is achieved. An effect and good reproduction characteristics can be obtained.

As shown in FIG. 6, in the speaker unit 20 having the above-described inner-magnet type magnetic circuit section 21,
The center pole 25 and the magnet 23 are provided with the ventilation holes 2.
The present invention can be applied to a device provided with 8. As in the embodiment shown in FIG. 3, the ventilation hole 28 extends from the internal space C of the speaker unit 20 including the diaphragm 26 and the magnetic circuit unit 21 to the outside of the unit as indicated by an arrow y in the drawing. To reduce the sound pressure in the internal space C of the speaker unit 20.

In this case as well, as in the case shown in FIG. 3, the sound absorbing material 27 made of a porous and hard material disposed on the tip end surface 25a of the center pole 25 is aligned with the vent hole 28. If it is formed in a ring shape, the sound to be reflected by the center pole 25 and the like can be absorbed by the sound absorbing material 27 without blocking the flow of the air.

In some internal magnet type magnetic circuit sections, a magnetic gap is formed with the side surface on the leading end side of the magnet itself facing the inner opening side end surface of the pot-shaped yoke, and there is no magnetic pole having a center pole. . In this case, the same effect can be obtained by mounting the sound absorbing material so as to face the rear surface of the diaphragm at the front end surface of the magnet.

Further, according to the present invention, a cone-shaped diaphragm 31 is provided.
Can also be applied to the speaker unit 30 having An example is shown in FIG. The speaker unit 30 shown in FIG. 7 includes a magnetic circuit portion 32, a diaphragm 31, and a support frame 33 that supports the diaphragm 31 with respect to the magnetic circuit portion 32.

The magnetic circuit section 32 is configured as an external magnet type magnetic circuit, and includes a yoke 35 having a center pole 34 at the center and a yoke 35 on the yoke 35 and around the center pole 34. It has a ring-shaped magnet 36 arranged and a ring-shaped plate 37 attached to the upper part of the magnet 36. The magnetic circuit section 32 forms a magnetic circuit by the magnet 36, the center pole 34 of the yoke 35, and the plate 37, and is formed by an inner end side end surface of the plate and a front end outer peripheral surface of the center pole 34. The magnetic flux of the magnet 36 is concentrated in the magnetic gap 38 provided therebetween.

Next, the diaphragm 31 is formed in a cone shape, and a cylindrical voice coil bobbin 40 around which a voice coil 39 is wound is attached to the base end side. The voice coil 39 faces the inside of the magnetic gap 38 of the magnetic circuit section 32. The voice coil 39 is connected to an external connection terminal 42 via a tinsel wire 41.

The edge portion 31a of the diaphragm 31
Are supported by a gasket 43 attached to the leading edge of the support frame 33. In addition, the diaphragm 3
A damper 44 for holding the voice coil 39 at the center of the magnetic gap 38 is provided on the base end side of the first. Further, a cap 45 for closing the center hole is attached to the center of the diaphragm 31.

In the speaker unit 30 configured as described above, the front end surface 34a of the center pole 34
The sound absorbing member 46 made of a porous and hard material may be attached to the diaphragm 31 so as to face the rear side of the diaphragm 31.

As described above, in the speaker unit 30 having the cone-shaped diaphragm 31 as well, the center pole 3 constituting the magnetic circuit portion 32 is provided on the back side of the diaphragm 31.
If the sound absorbing material 46 is attached to the front end surface 34a of the speaker unit 4, the sound absorbing material 46 can exhibit excellent sound absorbing power even in an environment where a high sound pressure and a high flow velocity in the speaker unit 30 are provided. It is possible to prevent the generation of frictional sound and the like and the loss of sound energy due to the vibration of the sound absorbing material 46, and the speaker unit 30 can exhibit high-quality reproduction characteristics with little noise and a bright and clear start-up.

[0036]

According to the speaker unit of the present invention, the member constituting the magnetic circuit portion on the back side of the diaphragm is provided with a porous and hard sound absorbing material and a frequency different from that of the sound absorbing material. And a sound absorbing member having a cross-sectional shape corresponding to the shape of the diaphragm is attached, so that excellent sound absorbing power can be exhibited, and this sound absorbing material is also provided. It can prevent itself from being vibrated. Further, the center pole according to the speaker unit of the present invention has a ventilation hole communicating the back side of the diaphragm and the outside of the speaker unit , and a ring is formed on a tip end surface of the center pole in accordance with the ventilation hole. A porous, hard sound absorbing material is attached, and a porous, hard sound absorbing material is attached so as to close the inner wall and the opening of the vent hole of the center pole. Therefore, similarly excellent sound absorbing power can be exhibited, and the sound absorbing material itself can be prevented from being vibrated.

Therefore, even if the internal space on the back side of the diaphragm in the speaker unit has a high sound pressure and a high air flow rate, it can sufficiently absorb the reflected sound and the like reflected on the magnetic circuit section and the like, and the sound absorbing material itself can be absorbed. It is possible to provide a speaker unit having a bright, clear, and well-starting reproduction characteristic with less noise, which can prevent generation of frictional noise and loss of sound energy due to vibration of the sound.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view showing a case where the present invention is applied to a speaker unit having an external-magnet type magnetic circuit unit.

FIGS. 2A and 2B are enlarged fragmentary side views showing a sound absorbing material mounting portion of the speaker unit, wherein FIGS. 2A and 2B show modified examples of the shape of the sound absorbing material. FIGS.

FIG. 3 is a cross-sectional side view showing many examples of the speaker unit.

FIG. 4 is a cross-sectional side view showing still another example of the speaker unit.

FIG. 5 is a cross-sectional side view showing a case where the present invention is applied to a speaker unit having an inner-magnet type magnetic circuit unit.

FIG. 6 is a cross-sectional side view showing another example when used for the speaker unit.

FIG. 7 is a cross-sectional side view showing a case where the present invention is applied to a speaker unit having a cone-shaped diaphragm.

[Explanation of symbols]

 1, 20, 30 ... speaker unit 2, 21, 32 ... magnetic circuit section 3, 26, 31 ... diaphragm 5, 25, 34 ... center pole 6, 22, 35 ... yoke 7, 23, 36 ... magnet 10, 39 ... voice coil 12, 16, 27, 46 ... sound absorbing material

Claims (3)

(57) [Claims] 1. A speaker unit comprising at least a diaphragm to which a voice coil is attached, and a magnetic circuit unit having a magnet and a yoke, wherein the magnetic circuit unit is located on the back side of the diaphragm. The constituent member is provided with a porous and hard sound absorbing material and a soft sound absorbing material having a sound absorbing effect of a different frequency from the sound absorbing material, which are overlapped with each other, and have a cross-sectional shape adapted to the shape of the diaphragm. A speaker unit comprising a sound absorbing member. 2. A speaker unit comprising at least a diaphragm to which a voice coil is attached, and a magnetic circuit unit having a magnet and a center pole, wherein the center pole is located on the back side of the diaphragm and the speaker unit. A speaker unit having a ventilation hole communicating with the outside of the speaker unit, and a porous and hard sound absorbing material formed in a ring shape in accordance with the ventilation hole is attached to a tip end surface of the center pole. . 3. A speaker unit comprising at least a diaphragm to which a voice coil is attached, and a magnetic circuit unit having a magnet and a center pole, wherein the center pole is located on the back side of the diaphragm and the speaker unit. Having a ventilation hole communicating with the outside of the center pole, and closing an inner wall portion and an opening of the ventilation hole of the center pole .
Cormorants, the speaker unit, characterized by comprising attaching the sound absorbing material of the rigid porous.