JP2009100292A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease the number of components and assembly man-hours while making a speaker thin by using a common magnet for the upper-and lower-pitched sounds. <P>SOLUTION: The speaker includes a first diaphragm, a magnetic circuit having an annular magnetic gap for vibrating the first diaphragm at a rear portion, and an annular first voice coil bonded to the front of the first diaphragm to be inserted into the magnetic gap. The magnetic circuit includes a plate disposed inside the first voice coil, a magnet stacked on the front of the plate inside the first voice coil, and a metallic yoke stacked on the front of the magnet and enclosing a periphery of the first voice coil to formed a gap with the magnet as a first magnetic gap. An second magnetic gap which is an annular groove is formed on the front of the yoke. The annular second voice coil bonded to the back of the second diaphragm is inserted into the second magnetic gap to drive two diaphragms by the one magnetic circuit. <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, like other electronic devices, a speaker is also required to be thin and have a reduced number of parts and assembly man-hours.
For this reason, an object of the present invention is to realize a thinner speaker and to reduce the number of parts and the number of assembly steps by making it possible to use a common magnet for the low-frequency magnetic circuit and the high-frequency magnetic circuit. It is.

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 magnet superimposed on the front surface of the plate inside the first voice coil;
A metal yoke that overlaps with the front surface of the magnet and surrounds the periphery of the first voice coil so that a gap with the magnet via the first voice coil is the first magnetic gap;
A second magnetic gap that is an annular groove is formed at the front of the yoke,
An annular second voice coil joined to the back surface of the second diaphragm is inserted into the second magnetic gap, thereby driving the first diaphragm and the second diaphragm with one magnetic circuit. It is characterized by that.

The invention according to claim 2 is the speaker according to claim 1,
The junction between the yoke and the magnet is characterized in that it is within the circumference of the second magnetic gap, which is the annular groove.

The invention according to claim 3 is the speaker according to claim 2,
The magnet has an outer periphery larger than a circumference of the second magnetic gap;
The yoke is characterized in that a protrusion having an outer periphery smaller than the circumference is formed so that the joint portion is within the circumference of the second magnetic gap.

According to the present invention, the 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 magnet. The first magnetic flux emitted from the side surface of the magnetic flux 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 front surface of the magnet (joint surface with the yoke) is applied to the yoke. It enters, passes through the second voice coil from the second magnetic gap, 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.

  As described above, conventionally, high-frequency and low-frequency magnets are required, respectively, but in the present invention, one magnet can be shared for high-frequency and low-frequency sounds. As a result, the number of magnets installed can be reduced, and the entire speaker can be made thinner. Further, the number of assembly steps can be reduced accordingly.

  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 protruding forward is formed at the center of the frame 2, and the plate 8, the magnet 5, and the yoke 6 constituting the magnetic circuit 9 are locked by screws 7 at the tip thereof. ing.

  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 magnet 5 is formed in a columnar shape, and a through hole 51 through which the screw 7 passes is formed at the center thereof. The 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. The outer circumference of the magnet 5 is set larger than the circumference of a high-frequency magnetic gap described later.

  The yoke 6 is made of metal, is placed on the front surface of the magnet 5, and is disposed between the magnet 5 and the treble diaphragm 4 so as to surround the bass voice coil 32. The yoke 6 is integrally provided with a main body portion 61 to which the 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 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 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). As a result, the joint portion between the main body 61 of the yoke 6 and the magnet 5 is accommodated within the circumference of the annular groove 64. FIG. 3 is a cross-sectional perspective view showing the flow of magnetic flux in the plate 8, the magnet 5, and the yoke 6. In the figure, arrows indicate the flow of magnetic flux. As shown in FIG. 3, 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. As a result, the treble magnetic flux (arrow Q) passing through the main body 61 of the yoke 6 passes through the treble magnetic cap having a smaller resistance than the magnetoresistive portion 68. The inner diameter of the annular groove 64 is set 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.
When an audio signal is input, the low-frequency magnetic flux emitted from the side surface of the magnet 5 based on the signal passes through the low-frequency voice coil 32 from the low-frequency magnetic gap (gap 66) and extends from the yoke 6. Part 62 is reached. Thereby, sound wave radiation is performed from the diaphragm 3 for bass.
On the other hand, the high-frequency magnetic flux emitted from the upper surface of the magnet 5 (joint surface with the yoke 6) based on the audio signal enters the main body portion 61 of the yoke 6 and avoids the magnetoresistive portion, thereby generating high-frequency magnetism. The treble voice coil 41 passes through the gap (annular groove 64) and reaches the main body 61 of the yoke 6 again. Thereby, sound waves are emitted from the treble diaphragm 4.

  As described above, according to this embodiment, even with one magnet 5, it is possible to cause a high-frequency magnetic flux and a low-frequency magnetic flux to flow in the magnetic gap. That is, the low-frequency diaphragm 3 and the high-frequency diaphragm 4 can be driven by one magnetic circuit 9. Thus, if one magnet 5 can be shared for high and low sounds, the number of magnets 5 can be reduced, and accordingly, the speaker 1 can be made thinner, Assembly time can also be reduced.

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

  The projection 63 of the yoke 6 is set to have an outer periphery smaller than the circumference of the treble magnetic gap, and the projection 63 and the magnet 5 are joined, so that the magnet 5 is the circumference of the treble magnetic gap. Even if it has a larger outer periphery, the joint portion between the yoke 6 and the magnet 5 will fit within the circumference of the high-frequency magnetic gap. This makes it possible to make the size of the magnet 5 larger than the magnetic gap for treble while making it easier for the magnetic flux to enter the treble 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, the case where the magnet 5 is joined to the projection 63 of the yoke 6 has been described as an example, but the magnet 5 may be joined to the rear surface of the yoke 6a without the projection 63 as shown in FIG. In this case, the outer periphery of the magnet 5a needs to be smaller than the circumference in order to fit the joint portion between the main body 61a of the yoke 6a and the magnet 5a within the circumference of the treble magnetic gap. For this reason, in order to ensure the size of the magnet as large as possible, it is preferable to join the magnet 5 to the protrusion 63.

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 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 the modification of the speaker of FIG. 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 Magnet 6 Yoke 7 Screw 8 Plate 9 Magnetic circuit 21 Protrusion 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)
65 Screw hole 66 Clearance (first magnetic gap)

Claims (3)

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 magnet superimposed on the front surface of the plate inside the first voice coil;
A metal yoke that overlaps the front surface of the magnet and surrounds the periphery of the first voice coil so that a gap with the magnet via the first voice coil is the first magnetic gap;
A second magnetic gap that is an annular groove is formed at the front of the yoke,
An annular second voice coil joined to the back surface of the second diaphragm is inserted into the second magnetic gap, thereby driving the first diaphragm and the second diaphragm with one magnetic circuit. A speaker characterized by that. The speaker according to claim 1, wherein
The joint part of the said yoke and a magnet is settled in the circumference | surroundings of the said 2nd magnetic gap which is the said annular groove. The speaker according to claim 2, wherein
The magnet has an outer periphery larger than a circumference of the second magnetic gap;
The speaker according to claim 1, wherein a protrusion having an outer periphery smaller than the circumference is formed on the yoke so that the joint portion is within the circumference of the second magnetic gap.

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