JP2009164694A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin speaker suppressing sound pressure drop. <P>SOLUTION: This speaker is provided with: a first diaphragm, a magnetic circuit having an annular first magnetic gap for vibrating the first diaphragm, and an annular first voice coil inserted in the first magnetic gap. The magnetic circuit is provided with: a plate arranged inside the first voice coil; a first magnet superposed on the plate; and a yoke superposed on the first magnet, surrounding the circumference of the first voice coil, and thereby making a gap between the first magnet and itself through the first voice coil the first magnetic gap. A second gap being an annular groove is formed in the front part of the yoke, A second magnet repelling the first magnet is superposed to be arranged in the circumference of the second magnetic gap. An annular second voice coil jointed to the back surface of a second diaphragm is inserted in the second magnetic gap, and the second magnet is housed in the second diaphragm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a speaker.

Conventionally, a speaker has a magnetic circuit on the back side of the sound reflecting surface of the diaphragm. However, in order to reduce the thickness of the entire speaker, the Jinkasa type is configured to have a magnetic circuit on the front of the diaphragm. The speaker called is being developed. In addition, in such a Jinkasa type speaker, by mounting another magnetic circuit and a diaphragm on the magnetic circuit provided on the front surface of the diaphragm, the vibration of the bass speaker is placed in front of the bass speaker. A coaxial 2WAY speaker in which a high-frequency speaker is arranged coaxially with a plate has also been developed (see, for example, Patent Document 1). More specifically, as shown in FIG. 5, the conventional 2WAY speaker 100 is provided with a low-frequency speaker 110 and a high-frequency speaker 120.
The low-frequency speaker 110 includes a low-frequency diaphragm 112 held around a frame 111, a low-frequency voice coil 113 extending forward from the center of the low-frequency vibration plate 112, and a tip of the low-frequency voice coil 113. And a low-pitched magnetic circuit 114 for driving the low-pitched voice coil 113 is provided. The low-frequency magnetic circuit 114 has a configuration in which a yoke 115, a magnet 116, and a plate 117 are stacked and integrated. The yoke 115 is formed in a columnar shape, and a part of its side surface extends outward. An annular magnet 116 and an annular plate 117 are attached to the inner surface of the extension portion 118. At this time, the magnet 116 and the plate 117 are attached so that a predetermined gap is formed between the inner peripheral surface of the plate 117 and the yoke 115. As a result, the tip of the bass voice coil 113 is inserted into the magnetic gap 119 formed between the plate 117 and the yoke 115.
When a music signal is applied to the bass voice coil 113, the bass voice coil 113 slides up and down by the magnetic flux of the bass magnetic circuit 114 and is joined to the bass voice coil 113. The plate 112 is vibrated and emits sound.

On the other hand, the treble speaker 120 includes a treble magnetic circuit 121 and a treble diaphragm 122. The treble magnetic circuit 121 is provided with a magnet 123 attached to the outer surface of the extending portion 118 of the yoke 115 in the bass magnetic circuit 114 and a plate 124. Here, similarly to the low-frequency magnetic circuit 114, the magnet 123, the inner peripheral surface of the plate 124, and the yoke 115 are attached so as to form a predetermined gap. The treble diaphragm 122 is formed in a dome shape, and a peripheral portion thereof is a treble voice coil 126 disposed in a magnetic gap 125 between the yoke 115 and the plate 124.
When a music signal is applied to the treble voice coil 126, the treble voice coil 126 slides up and down by the magnetic flux of the treble magnetic circuit 121 and is joined to the treble voice coil 126. The plate 122 is vibrated and emits sound.
JP 2003-299192 A

By the way, as with other electronic devices, a speaker is required to be thin. However, it is desired that the speaker be thin while suppressing a decrease in sound pressure.
For this reason, the subject of this invention is providing the thin speaker which suppressed the sound pressure fall.

The speaker according to the invention of claim 1 is:
A first diaphragm;
A magnetic circuit disposed in front of the first diaphragm and having an annular first magnetic gap for vibrating the first diaphragm at a rear portion;
An annular first voice coil joined to the front surface of the first diaphragm and inserted into the first magnetic gap;
The magnetic circuit is:
A plate disposed inside the first voice coil;
A first magnet superimposed on the front surface of the plate inside the first voice coil;
A metal yoke that overlaps the front surface of the first magnet and surrounds the periphery of the first voice coil so that a gap with the first magnet via the first voice coil serves as the first magnetic gap. And
A second magnetic gap, which is an annular groove, is formed in the front portion of the yoke, and a second magnet whose magnetic pole direction is opposite to that of the first magnet is within the circumference of the second magnetic gap. It ’s layered to fit,
An annular second voice coil joined to the back surface of the second diaphragm is inserted into the second magnetic gap, and the second magnet is housed in the second diaphragm. .

The invention according to claim 2 is the speaker according to claim 1,
An annular notch is formed so as to surround the joint portion at a position outside the joint portion of the yoke with the first magnet and outside the second magnetic gap. It is said.

The invention according to claim 3 is the speaker according to claim 2,
The cutout portion is characterized in that a front end surface of the cutout portion is formed in front of the bottom surface of the second magnetic gap.

Invention of Claim 4 is a speaker as described in any one of Claims 1-3,
The second magnetic gap is characterized in that the depths of at least one portion and other portions are different.

  According to the present invention, the main magnet is joined to the yoke, and the first magnetic gap is formed by surrounding the first voice coil in a state where the yoke leaves a gap with respect to the main magnet. The first magnetic flux emitted from the side surface of the main magnet passes through the first voice coil from the first magnetic gap and reaches the yoke.

  In addition, since the second magnetic gap into which the second voice coil is inserted is formed in the front part of the yoke, the second magnetic flux emitted from the main magnet enters the yoke and the second magnetic gap is formed. From this time, it passes through the second voice coil and reaches the yoke again. Here, since the cross section of a part of the yoke is narrower than the other cross section by the annular groove, the part functions as a magnetoresistive part. As a result, the second magnetic flux passing through the yoke passes through the second magnetic cap having a smaller resistance than the magnetoresistive portion.

  Here, a high sound pressure cannot be obtained only by the induction of the second magnetic flux to the second magnetic gap by the magnetoresistive portion, but in the present invention, it is further within the circumference of the second magnetic gap at the front portion of the yoke. Since the sub-magnet repelling the main magnet is arranged, the second magnetic flux is attracted by the sub-magnet and easily passes through the second magnetic gap. Thereby, the driving force of the second voice coil is sufficiently obtained, and a high sound pressure is obtained.

The sub-magnet only induces the second magnetic flux into the second magnetic gap and is housed inside the second diaphragm. The entire speaker can be made thinner than the speaker that requires each of the magnetic circuits.
From the above, it is possible to provide a thin speaker that suppresses a decrease in sound pressure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of the speaker according to the present embodiment, and FIG. As shown in FIGS. 1 and 2, the speaker 1 includes a frame 2, a low-frequency diaphragm (first diaphragm) 3 supported by the frame 2, and a protrusion 21 provided at the center of the bottom surface of the frame 2. And a treble diaphragm (second diaphragm) 4 provided in the magnetic circuit 9 is provided. For convenience of explanation, as shown in FIG. 1, the upper part of the drawing is “front” in the speaker 1, and the lower part of FIG.

  The frame 2 covers the back side of the diaphragm 3 for bass and supports the diaphragm 3 for bass. A projection 21 projecting forward is formed at the center of the frame 2, and a plate 8 constituting the magnetic circuit 9, a main magnet (first magnet) 5, and a yoke 6 are formed at the tip thereof. It is locked by a screw 7.

  The low-frequency sound diaphragm 3 is formed in a substantially conical shape so as to be recessed rearward, and a through hole 31 through which the projection 21 of the frame 2 passes is formed at the center. An annular bass voice coil (first voice coil) 32 extending forward from the front surface is joined around the through hole 31 on the front surface of the bass diaphragm 3.

  The treble diaphragm 4 is formed in a dome shape so as to be convex toward the front, and on the rear surface of the periphery thereof, an annular high-pitched voice coil (second sound) extending rearward from the rear surface. Voice coil) 41 is joined.

  The plate 8 is formed of a metal in a cylindrical shape, and a through hole 81 through which the screw 7 passes is formed at the center. The plate 8 is disposed between the low-pitched diaphragm 3 and the high-pitched diaphragm 4 and inside the low-pitched voice coil 32.

  The main magnet 5 is formed in a cylindrical shape, and a through hole 51 through which the screw 7 passes is formed at the center. The main magnet 5 is superimposed on the front surface of the plate 8 so as to be disposed between the low-frequency diaphragm 3 and the high-frequency diaphragm 4 and inside the low-frequency voice coil 32. Here, the main magnet 5 is disposed so that the south pole is the front and the north pole is the rear. Moreover, the outer periphery of the main magnet 5 is set larger than the circumference of a high-frequency magnetic gap described later.

  The yoke 6 is made of metal, and is disposed between the main magnet 5 and the treble diaphragm 4 so as to be superimposed on the front surface of the main magnet 5 and to surround the bass voice coil 32. The yoke 6 is integrally provided with a main body portion 61 to which the main magnet 5 is joined on the rear surface and an extending portion 62 extending rearward from the peripheral edge portion of the main body portion 61.

  The extending portion 62 surrounds the low-pitched voice coil 32 with a gap 66 formed on the side surface of the main magnet 5. As a result, the bass voice coil 32 is disposed in the gap 66, so that the gap 66 acts as a bass magnetic gap (first magnetic gap).

  On the rear surface of the main body 61, a protrusion 63 that protrudes rearward and a screw hole 65 into which the screw 7 is screwed at the center of the protrusion 63 are formed. The protrusion 63 is formed in a circular shape, and its outer diameter is set smaller than the outer diameter of the main magnet 5.

  On the front surface of the main body 61, an annular groove 64 in which the tip of the treble voice coil 41 is inserted is formed. Thus, since the high-pitched voice coil 41 is inserted into the annular groove 64, the annular groove 64 acts as a high-pitched magnetic gap (second magnetic gap). Thereby, the joint portion between the main body 61 of the yoke 6 and the main magnet 5 is accommodated within the circumference of the annular groove 64.

  FIG. 3 is a front view of the yoke 6 showing the outer shape of the annular groove 64. The annular groove 64 is radially divided into six, and the depths are alternately different. Specifically, in FIG. 3, the depth of the black portion B is set deeper than the white portion W.

  A circular recess 61 a is formed in the circumference of the annular groove 64 on the front surface of the main body 61. As shown in FIGS. 1 and 2, the disc-shaped submagnet (second magnet) 10 is fitted in the recess 61 a, so that the submagnet 10 is accommodated in the treble diaphragm 4. Become. The submagnet 10 is fitted in the recess 61a so that the S pole is the rear and the N pole is the front, that is, the direction of the magnetic pole is opposite to that of the main magnet 5. The magnet 5 is repelled.

  An annular notch 11 is formed on the rear surface of the main body 61 outside the joint portion with the main magnet 5 and outside the annular groove 64 so as to surround the joint portion. . The notch 11 is formed such that the front end surface 11 a of the notch 11 is positioned in front of the bottom surface 64 a of the annular groove 64.

FIG. 4 is a cross-sectional perspective view showing the flow of magnetic flux in the plate 8, the main magnet 5, the sub magnet 10, and the yoke 6. In the figure, arrows indicate the flow of magnetic flux. As shown in FIG. 4, the section of the main body 61 of the yoke 6 is narrower than the other sections by the annular groove 64, so that the section functions as the magnetoresistive section 68. Further, the high-frequency magnetic flux (arrow Q) is guided to the high-frequency magnetic gap (annular groove 64) by the notch 11. As a result, the treble magnetic flux (arrow Q) passing through the body 61 of the yoke 6 passes through the treble magnetic cap having a smaller resistance than the magnetoresistive portion 68. Further, since the sub-magnet 10 repelling the main magnet 5 attracts high-frequency magnetic flux, the high-frequency magnetic flux easily passes through the high-frequency magnetic gap.
The inner diameter of the annular groove 64 is set to be larger than the outer diameter of the protrusion 63 in order to allow the magnetic flux to flow efficiently through the treble magnetic gap. Further, the optimum value of the depth of the annular groove 64 is determined by the size and output of the speaker 1, but this value is determined by various simulations and experiments.

Next, the operation of this embodiment will be described.
The low-frequency magnetic flux emitted from the side surface of the main magnet 5 passes through the low-frequency voice coil 32 from the low-frequency magnetic gap (gap 66) and reaches the extending portion 62 of the yoke 6. Here, when the audio signal is input to the bass voice coil 32, the bass voice coil 32 reacts with the magnetic force and vibrates back and forth. Since the bass voice coil 32 is connected to the bass diaphragm 3, the vibration of the bass voice coil 32 is transmitted to the bass diaphragm 3. Thereby, sound wave radiation is performed from the diaphragm 3 for bass.
On the other hand, the treble magnetic flux emitted from the main magnet 5 enters the yoke 6, passes through the treble voice coil 41 from the treble magnetic gap (annular groove 64) while avoiding the magnetic resistance portion 68, and again. The yoke 6 is reached. Here, when an audio signal is input to the treble voice coil 41, the treble voice coil 41 reacts with the magnetic force and vibrates back and forth. Since the treble voice coil 41 is connected to the treble diaphragm 4, the vibration of the treble voice coil 41 is transmitted to the bass diaphragm 4. Thereby, sound waves are emitted from the treble diaphragm 4.

  As described above, according to the present embodiment, the sub-magnet 10 that repels the main magnet 5 is disposed within the circumference of the annular groove 64 in the front portion of the yoke 6. The magnetic flux is attracted and easily passes through the treble magnetic gap. As a result, the driving force of the high-pitched voice coil 41 can be sufficiently obtained, and a high sound pressure can be obtained.

The sub-magnet 10 merely guides the high-frequency magnetic flux into the high-frequency magnetic gap, and further, is housed in the high-frequency vibration plate 4. Even when compared with a speaker that requires each magnetic circuit for bass, the entire speaker can be made thinner.
From the above, it is possible to provide a thin speaker that suppresses a decrease in sound pressure.

  In addition, an annular notch 11 is formed so as to surround the joint portion at a position outside the joint portion of the yoke 6 with the main magnet 5 and outside the treble magnetic gap. This notch portion 11 becomes an obstacle to the magnetic flux path to the magnetoresistive portion 68. As a result, the magnetic flux passing through the yoke 6 easily passes through the treble magnetic gap.

  Furthermore, since the front end surface 11 a of the notch portion 11 is positioned in front of the bottom surface 64 a of the high-frequency magnetic gap, the notch portion 11 covers the side of the magnetoresistive portion 68, and the magnetoresistive portion 68 is covered. High-frequency magnetic flux is less likely to flow.

Further, since the treble magnetic gap has different depths between at least one portion and the other portion, the thickness of the magnetoresistive portion 68 also varies depending on the location. For this reason, the resistance of the magnetoresistive portion 68 also increases, and the high-frequency magnetic flux easily passes through the high-frequency magnetic gap.
In the present embodiment, the treble magnetic gap (annular groove 64) is divided into six so as to have different depths alternately, but the present invention is not limited to this. Here, by partially increasing the depth of the annular groove 64, the magnetic conducting portion is reduced and the magnetoresistive portion is increased, thereby encouraging the flow of magnetic force to the treble magnetic gap, resulting in high magnetic flux. It becomes possible. Therefore, in addition to the above-described embodiment, it is also possible to increase the magnetoresistive portion by providing a plurality of through holes in the annular groove 64, for example.

  Further, since the joint portion between the main body 61 of the yoke 6 and the main magnet 5 is within the circumference of the high-pitched magnetic gap that is the annular groove 64, the magnetic flux emitted from the main magnet 5 and passed through the joint portion. It becomes easier to enter the magnetic gap for high sound, and the sound output efficiency can be increased.

  The protrusion 63 of the yoke 6 is set to have an outer periphery smaller than the circumference of the high sound magnetic gap, and the protrusion 63 and the main magnet 5 are joined, so that the main magnet 5 is connected to the high sound magnetic gap. Even if the outer circumference is larger than the circumference, the joint portion between the yoke 6 and the main magnet 5 is within the circumference of the treble magnetic gap. This makes it possible to make the size of the main magnet 5 larger than the high-frequency magnetic gap while making it easier for the magnetic flux to enter the high-frequency magnetic gap. Therefore, the magnetic force of the magnetic circuit 9 can be further maintained, and the sound pressure can be easily maintained.

Of course, the present invention is not limited to the above-described embodiment and can be modified as appropriate.
For example, in the present embodiment, a case where three black portions B of the six-divided annular grooves 62 are formed deeper than the other white portions W is illustrated. It may be. Further, the deep portion is not limited to three portions as long as it is at least one portion.

It is sectional drawing which shows schematic structure of the speaker which concerns on this embodiment. It is an enlarged view which shows the inside of the dashed-dotted line part of FIG. It is a front view of the yoke which shows the external shape of the annular groove with which the speaker of FIG. 1 is equipped. It is a cross-sectional perspective view which shows the flow of the magnetic flux in the plate which concerns on this embodiment, a magnet, and a yoke. It is sectional drawing which shows schematic structure of the conventional speaker.

Explanation of symbols

1 Speaker 2 Frame 3 Diaphragm for low sound (first diaphragm)
4 Diaphragm for high sound (second diaphragm)
5 Main magnet (first magnet)
6 Yoke 7 Screw 8 Plate 9 Magnetic circuit 10 Sub magnet (second magnet)
11 Notch 11a Tip surface 21 Projection 31 Through hole 32 Voice coil for low sound (first voice coil)
41 Voice coil for treble (second voice coil)
51 through-hole 61 main body 62 extension 63 protrusion 64 annular groove (second magnetic gap)
64a Bottom surface 65 Screw hole 66 Clearance (first magnetic gap)

Claims (4)

A first diaphragm;
A magnetic circuit disposed in front of the first diaphragm and having an annular first magnetic gap for vibrating the first diaphragm at a rear portion;
An annular first voice coil joined to the front surface of the first diaphragm and inserted into the first magnetic gap;
The magnetic circuit is:
A plate disposed inside the first voice coil;
A first magnet superimposed on the front surface of the plate inside the first voice coil;
A metal yoke that overlaps the front surface of the first magnet and surrounds the periphery of the first voice coil so that a gap with the first magnet via the first voice coil serves as the first magnetic gap. And
A second magnetic gap, which is an annular groove, is formed in the front portion of the yoke, and a second magnet whose magnetic pole direction is opposite to that of the first magnet is within the circumference of the second magnetic gap. It ’s layered to fit,
An annular second voice coil joined to the back surface of the second diaphragm is inserted into the second magnetic gap, and the second magnet is housed in the second diaphragm. Speaker. The speaker according to claim 1, wherein
An annular notch is formed so as to surround the joint portion at a position outside the joint portion of the yoke with the first magnet and outside the second magnetic gap. Speaker. The speaker according to claim 2, wherein
The speaker is characterized in that the cutout portion is formed such that a front end surface of the cutout portion is located in front of a bottom surface of the second magnetic gap. The speaker according to any one of claims 1 to 3,
The speaker according to claim 2, wherein the second magnetic gap has different depths at least in one part and the other part.

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