JP6397494B2 - Speaker unit and speaker provided with the speaker unit - Google Patents

Description

  The present invention relates to a speaker unit and a speaker including the speaker unit.

A speaker unit that improves acoustic characteristics is known.
For example, the speaker unit described in Patent Document 1 includes a magnetic circuit, a voice coil, a dome-shaped diaphragm, and a support column that supports the diaphragm.

  A dome-shaped space between the diaphragm and the magnetic circuit communicates with a space behind the magnetic circuit through a hole provided in the support column. According to such a configuration, since the space on the back side of the diaphragm is enlarged, the suppression of back pressure fluctuation is alleviated and the acoustic characteristics are improved.

International Publication No. 2010/023759

Incidentally, a speaker unit having a ring-shaped diaphragm is known.
This type of speaker unit is often used as a loudspeaker (tweeter). For this reason, the actual situation is that there has been no improvement in the mid-low range.

  The present invention has been made in view of such circumstances, and an object of the present invention is a speaker unit having a ring-shaped diaphragm, which has superior acoustic characteristics in a mid-low range compared to a conventional structure. To provide a unit and a speaker including the speaker unit.

(1) A speaker unit that solves the above problems includes a ring-shaped diaphragm, a ring-shaped voice coil provided in a circumferential direction of the diaphragm at a radial intermediate portion of the diaphragm, and the voice coil In a speaker unit comprising a magnetic circuit having a magnetic gap to be inserted and a case having a sound path for guiding sound emitted from the diaphragm to the outside, at least an inner side of the voice coil of the diaphragm A first space is defined by the first portion, the voice coil, and the magnetic circuit, and at least a second portion outside the voice coil of the diaphragm, the voice coil, and the magnetic circuit. A second space is defined, at least one first communication hole communicating the first space and a rear space at the rear of the magnetic circuit, and the second space And at least one second communicating hole communicating the side space on the side of the magnetic circuit.
Another speaker unit for solving the above problems is a speaker unit, which is a ring-shaped diaphragm and a ring-shaped voice provided at a radial intermediate portion of the diaphragm along the circumferential direction of the diaphragm. A coil, a ring-shaped magnetic circuit having a magnetic gap through which the voice coil is inserted, a sound path for guiding the sound emitted from the diaphragm to the outside, and a rear space provided behind the diaphragm A ring-shaped first space is defined by at least a first portion inside the voice coil of the diaphragm, the voice coil, and the magnetic circuit, and at least of the diaphragm. A ring-shaped second space is defined by the second portion outside the voice coil, the voice coil, and the magnetic circuit. An internal space radially inside the air circuit, a side space radially outside the magnetic circuit, and a bottom space connecting the internal space and the side space, the first space and the internal space At least one first communication hole that communicates with each other, and at least one second communication hole that communicates between the second space and the side space.

  According to this configuration, the first space on the back side of the diaphragm is enlarged by the first space on the back side of the diaphragm and radially inward of the voice coil communicating with the rear space of the magnetic circuit. Is done. Further, the second space on the back side of the diaphragm and the outer side in the radial direction from the voice coil and the side space on the side of the magnetic circuit communicate with each other, so that the second space on the back side of the diaphragm is Enlarged. This enlarges the back cavity and improves the acoustic characteristics in the mid-low range.

  (2) The speaker unit may further include a phase plug provided on the diaphragm, and the sound path includes a ring-shaped portion formed between the case and the phase plug, The ring-shaped portion has a cross-sectional area that gradually decreases from the inner opening end toward the output opening end.

  In a speaker unit having a predetermined output opening end, a large-diameter diaphragm may be used to improve sound output. In this case, it is difficult to make the cross-sectional area of the output opening end of the speaker unit sufficiently large with respect to the size of the diaphragm. In this configuration, when the sound path is formed so that the cross-sectional area of the sound path gradually increases, the sound path width at the inner opening end of the sound path (the width of the ring-shaped inner opening end) becomes too narrow, and acoustic energy is released. The amount is limited.

  With respect to such a problem, according to the above configuration, the sound path width at the inner opening end of the sound path is sufficiently ensured, so that the utilization rate of acoustic energy is improved. Further, the transmission loss of the sound path is suppressed by gradually reducing the cross-sectional area of the ring-shaped portion in the sound path from the inner opening end toward the output opening end. For this reason, the efficiency of the speaker unit is improved.

  (3) In the speaker unit, the case includes a cover having the sound path and a case main body that houses the magnetic circuit, and the speaker unit is disposed between the cover and the magnetic circuit. A sealing member made of resin, wherein the diaphragm is disposed inside the sealing member between the cover and the magnetic circuit, and the at least one second communication hole is formed in the sealing member Including a groove or a through hole.

  The resin sealing member is easier to process than the plate. For this reason, according to the said structure, the productivity of a speaker unit improves compared with the case where a 2nd communicating hole is provided in a plate.

  (4) In the speaker unit, the magnetic circuit is provided on a ring-shaped magnet disposed on a radially outer side of the diaphragm than the voice coil, and on a surface of the magnet facing the diaphragm. A ring-shaped plate and a yoke disposed so as to form the magnetic gap with respect to the inner peripheral surface of the plate, and the yoke is provided on a surface of the magnet opposite to the plate. A back plate portion, a peripheral wall portion along the inner peripheral surface of the magnet, and a front plate portion covering the front end of the peripheral wall portion, and the first communication hole penetrates the front plate portion of the yoke. That is, in the case of an outer magnet type speaker unit, the first communication hole is provided in the yoke.

  (5) In the speaker unit, the magnetic circuit is provided on a ring-shaped magnet disposed on the radially inner side of the diaphragm with respect to the voice coil, and on a surface of the magnet facing the diaphragm. A circular plate; and a yoke provided on a surface of the magnet opposite to the plate and disposed so as to form the magnetic gap with respect to an outer peripheral surface of the plate. The communication hole penetrates the plate. That is, in the case of an internal magnet type speaker unit, the first communication hole is provided in the plate.

  (6) In the speaker unit, the case houses the diaphragm, the voice coil, and the magnetic circuit, and the rear space includes at least a portion of the magnetic circuit opposite to the diaphragm, The side space is partitioned by at least the side of the magnetic circuit and the case.

(7) The speaker unit includes a sealing member that is provided between the magnetic circuit and the case and partitions the second space and the side space, and the at least one second communication hole includes And a groove or a through hole formed in the sealing member so as to communicate the second space and the side space.
The other side speaker unit includes a ring-shaped diaphragm, a ring-shaped voice coil provided along a circumferential direction of the diaphragm at a radial intermediate portion of the diaphragm, and a magnetic gap through which the voice coil is inserted. A magnetic circuit, a case having a sound path for guiding the sound emitted from the diaphragm to the outside, and a phase plug provided on the diaphragm, wherein the sound path includes the case and the sound path. It includes a ring-shaped portion formed between the phase plug, and the ring-shaped portion of the sound path has a cross-sectional area that gradually decreases from the inner opening end toward the output opening end.

  (8) A speaker that solves the above problem includes the speaker unit described above. For this reason, this speaker is superior in acoustic characteristics in the mid-low range compared to a speaker having a ring-shaped diaphragm having a conventional structure.

  The speaker unit and the speaker have excellent acoustic characteristics in the mid-low range compared to the conventional structure.

The exploded view of the speaker unit concerning a 1st embodiment. The cross-sectional perspective view of a speaker unit. Enlarged view of the sound path. The graph which shows the change of the cross-sectional area of a sound path. The graph which shows an acoustic characteristic. The graph which shows an acoustic characteristic. The graph which shows an acoustic characteristic. The graph which shows an acoustic characteristic. Sectional drawing of the speaker unit which concerns on 2nd Embodiment.

(First embodiment)
The speaker unit according to the first embodiment will be described with reference to FIGS.
In the description of the first embodiment, “front side” and “front” indicate the side from which sound is output, and “rear side” and “rear” indicate the side opposite to the side from which sound is output. Further, the “back surface” indicates a surface opposite to a surface from which sound is output.

  As shown in FIG. 1, the speaker unit 1 includes a magnetic circuit 10, a diaphragm 20, a voice coil 21, a phase plug 30, and a case 40 (see FIG. 2) that accommodates these components. The phase plug 30 is a component for aligning the phases of sound waves.

FIG. 2 is a cross-sectional perspective view of the speaker unit 1.
As shown in FIGS. 1 and 2, the magnetic circuit 10 includes a ring-shaped magnet 11, a ring-shaped plate 12 disposed on the front surface of the magnet 11, and a magnetic gap G with respect to the inner peripheral surface 12 b of the plate 12. And a yoke 13 arranged so as to form

The yoke 13 has a back plate portion 14 disposed on the rear surface of the magnet 11 and a center portion 15 inserted through the center hole 11 a of the magnet 11.
The center portion 15 includes a peripheral wall portion 16 along the circumferential direction of the inner peripheral surface of the magnet 11, and a front plate portion 17 that covers the front end of the peripheral wall portion 16. There is an internal space SN inside the peripheral wall portion 16. That is, the internal space SN is partitioned by at least the peripheral wall portion 16 and the front plate portion 17. Note that the internal space SN is a concept belonging to a rear space existing behind the front surface of the magnetic circuit 10.

  The front plate portion 17 of the center portion 15 is located in the center hole 12a (see FIG. 1) of the plate 12. A gap (that is, a magnetic gap G) through which the voice coil 21 is inserted is provided between the outer peripheral surface 15a (see FIG. 1) of the center portion 15 and the inner peripheral surface 12b (see FIG. 1) of the plate 12.

  Further, the front plate portion 17 of the center portion 15 is provided with a connection portion 18 to which the phase plug 30 is connected. The connecting portion 18 protrudes from the center portion of the center portion 15. The diameter of the connecting portion 18 is smaller than the diameter of the front plate portion 17 of the center portion 15. A plurality of first communication holes 17 a are formed at equal intervals along the circumferential direction of the connection portion 18 in the front plate portion 17. Each first communication hole 17a communicates a first space SA, which will be described later, and an internal space SN (that is, the rear space). The first space SA is partitioned by at least a first portion (a portion including an inner ring portion 20a described later) inside the voice coil 21 of the diaphragm 20, the voice coil 21, and the yoke 13 of the magnetic circuit 10. Has been.

  The diaphragm 20 is formed of a ring-shaped plate member. A cylindrical voice coil 21 is attached to an intermediate portion in the radial direction of the diaphragm 20. In other words, a ring-shaped voice coil 21 provided along the circumferential direction of the diaphragm 20 is attached to a radially intermediate portion of the diaphragm 20. The diameter of the voice coil 21 is larger than the diameter of the output opening end 45 b of the speaker unit 1.

  The angle formed between the surface of the diaphragm 20 on the radially inner side of the voice coil 21 (hereinafter referred to as “inner ring portion 20a”) and the peripheral surface of the voice coil 21 is greater than 90 degrees. Similarly, the angle formed between the surface of the diaphragm 20 on the radially outer side of the voice coil 21 (hereinafter referred to as “outer ring portion 20 b”) and the peripheral surface of the voice coil 21 is more than 90 degrees. Is also big.

The inner peripheral portion of the inner ring portion 20 a of the diaphragm 20 is sandwiched between the base portion 31 of the phase plug 30 and the connecting portion 18 of the yoke 13.
The outer peripheral portion of the outer ring portion 20 b of the diaphragm 20 is sandwiched between a sealing member 49 and a cover 41 described later.

  The phase plug 30 includes a base portion 31 (see FIG. 3) connected to the connecting portion 18 of the yoke 13 via an intervening part 19, and a main body portion 32 provided on the base portion 31 and constituting the inner surface of the sound path LS. And have.

  The schematic shape of the main body portion 32 is a conical shape, and the main body portion 32 is formed so as to be narrowed from the base portion 31 toward the tip. The cross-sectional shape (cross-sectional outer shape) cut perpendicularly to the central axis C1 of the main body 32 is circular regardless of the position of the central axis C1. The side surface 32a of the main body 32 is warped toward the central axis C1. A ring-shaped space exists between the base 31 side portion of the main body portion 32 and the front plate portion 17 of the yoke 13. In this space, the inner ring portion 20a of the diaphragm 20 is disposed.

  The phase plug 30 is fastened by a bolt 33 inserted through a hole along the central axis C1. The head of the bolt 33 is disposed on the top of the phase plug 30. The head of the bolt 33 is preferably hemispherical or a similar shape.

The case 40 includes a cover 41 that covers the front side of the diaphragm 20, and a case body 46 that houses the diaphragm 20 and the magnetic circuit 10.
The case body 46 includes a side wall 47 that surrounds the side surface of the magnetic circuit 10 and a bottom wall 48.

  A space (hereinafter referred to as “side space SO”) is provided between the side wall 47 of the case body 46 and the magnetic circuit 10. A space (hereinafter referred to as “bottom space SD”) is provided between the bottom wall 48 of the case body 46 and the magnetic circuit 10. The bottom space SD is a concept belonging to the rear space of the magnetic circuit 10.

  The cover 41 includes a central portion 42 having a through hole 45 for focusing sound, a circumferential portion 43 provided around the central portion 42 and covering the front surface of the magnetic circuit 10, and provided around the circumferential portion 43. And an outer peripheral portion 44 connected to the side wall 47 of the case body 46.

  A ring-shaped sealing member 49 is disposed between the circumferential portion 43 of the cover 41 and the plate 12 of the magnetic circuit 10. The sealing member 49 is formed of resin or metal (for example, aluminum). The sealing member 49 is molded by, for example, a mold.

The diaphragm 20 is disposed in a space between the cover 41 and the magnetic circuit 10 and inside the sealing member 49.
A plurality of second communication holes 49 a are provided at equal intervals in the circumferential direction between the sealing member 49 and the plate 12. Each second communication hole 49 a extends along the radial direction of the sealing member 49 and the plate 12.

  For example, each second communication hole 49 a is configured as a groove in which a part of the surface of the plate 12 of the sealing member 49 is cut out. Each second communication hole 49 a allows the space on the back surface side of the outer ring portion 20 b (hereinafter referred to as “second space SB”) and the side space SO in the case 40 to communicate with each other. The second space SB is partitioned by at least a second portion outside the voice coil 21 of the diaphragm 20 (a portion including the outer ring portion 20b), the voice coil 21, and the plate 12 of the magnetic circuit 10. Yes.

  The through hole 45 provided in the center portion 42 of the cover 41 is formed so as to gradually narrow from the inner opening end 45a toward the output opening end 45b. The cross-sectional shape (cross-sectional outer shape) cut perpendicularly to the central axis C2 of the through hole 45 is circular regardless of the position of the central axis C2. A phase plug 30 is disposed in the through hole 45. The space between the through hole 45 and the phase plug 30 constitutes a part of the sound path LS that guides sound. The sound path LS guides the sound emitted from the diaphragm 20 to the outside.

  As described above, the speaker unit 1 includes a plurality of first communication holes 17a that allow the first space SA on the back side of the diaphragm 20 and the internal space SN to communicate with each other, and the second space SB on the back side of the diaphragm 20 and the side. A plurality of second communication holes 49a for communicating with the partial space SO are provided. Below, the effect | action by the some 1st communicating hole 17a and the some 2nd communicating hole 49a is demonstrated.

  It is known that the efficiency of the mid-low range can be improved by enlarging the space on the back side of the diaphragm 20. When the speaker unit 1 has the above-described structure, that is, when the space on the back surface side of the diaphragm 20 is partitioned by the voice coil 21 into the inner first space SA and the outer second space SB, It is conceivable that either one of the first space SA and the second space SB communicates with the bottom space SD.

  However, although the first space SA and the second space SB communicate with each other through the magnetic gap G, the magnetic gap G is a barrier for air movement because the width of the magnetic gap G is small. In addition, when a communication hole communicating with the rear space is provided in only one of the first space SA and the second space SB, a resonance mode sound wave can be formed. In consideration of this, in the present embodiment, a communication hole is provided separately for each of the first space SA and the second space SB that are separated from each other by the voice coil 21 on the back side of the diaphragm 20.

  Further, in the first embodiment, the first space SA on the inner side of the voice coil 21 is communicated with the internal space SN of the yoke 13 disposed with the plate 12 interposed therebetween. That is, the first space SA is communicated with the internal space SN by the first communication hole 17a having a relatively short length. For this reason, the communication space constituted by the first space SA and the internal space SN is less stiff than the communication space constituted by the communication between the first space SA and the bottom space SD. Also, the second space SB outside the voice coil 21 is communicated with the side space SO arranged with the sealing member 49 interposed therebetween. That is, the second space SB communicates with the side space SO through the second communication hole 49a having a relatively short length. For this reason, the communication space constituted by the second space SB and the side space SO has a smaller stiffness than the communication space constituted by the communication between the second space SB and the bottom space SD. As a result, both the influence on the inner ring part 20a of the diaphragm 20 due to the pressure fluctuation in the first space SA and the influence on the outer ring part 20b of the diaphragm 20 due to the pressure fluctuation in the second space SB become relatively small. Conceivable.

  That is, when a communication hole is provided in one of the first space SA and the second space SB, the efficiency may be reduced in a part of the midrange due to the resonance mode, but the first space SA and the second space SB By providing the communication holes in both, the generation of the resonance mode is suppressed and the efficiency reduction in the mid range is reduced. In addition, since it is considered that the suppression of back pressure fluctuation is alleviated as both the stiffness of the communication space including the first space SA and the stiffness of the communication space including the second space SB are reduced, the first communication hole 17a and the second communication hole 17a. It is considered that the reduction in efficiency in the mid-range is further suppressed by shortening the hole 49a.

  The cross-sectional area of the first communication hole 17a and the cross-sectional area of the second communication hole 49a are appropriately set. By adjusting the cross-sectional area of the first communication hole 17a and the cross-sectional area of the second communication hole 49a, it is possible to adjust the efficiency improvement width in the mid-low range. For example, by reducing these cross-sectional areas, the efficiency improvement range in the mid-low range can be suppressed, and thereby the clarity of the sound (easy to hear the sound) can be improved.

Next, the structure of the sound path LS will be described with reference to FIG. FIG. 3 shows an enlarged view of the sound path LS.
The sound path LS includes a portion configured as a space between the through hole 45 and the phase plug 30 (hereinafter, a ring-shaped portion), and a portion where the phase plug 30 is not disposed in the through hole 45 (hereinafter, a cylindrical portion). ).

The cross-sectional shape of the ring-shaped portion in the sound path LS gradually decreases from the inner opening end 45a toward the output opening end 45b.
In addition, at least the cross-sectional area of the ring-shaped portion in the sound path LS gradually decreases from the inner opening end 45a toward the output opening end 45b. As a result, in the first embodiment, the sound path LS is configured such that the cross-sectional area of the inner opening end 45a is larger than the cross-sectional area of the output opening end 45b.

In the prior art, for the purpose of improving the efficiency of the speaker unit 1, the cross-sectional area of the sound path LS is gradually enlarged from the inner opening end 45a toward the output opening end 45b.
On the other hand, the present technology has a configuration opposite to that of the conventional technology. The advantages obtained by such a configuration will be described below.

  The diameter of the output opening end 45b is set by a standard, for example. On the other hand, the size of the diaphragm 20 is arbitrarily set. When a high output speaker unit 1 is required, a large diaphragm 20 is used. In the first embodiment, the diameter of the diaphragm 20 (the diameter at the portion corresponding to the voice coil 21) is larger than the diameter of the output opening end 45b. As the diameter of the diaphragm 20 increases, the diameter of the inner opening end 45a of the sound path LS also increases correspondingly. In such a case, if it is assumed that the cross section of the sound path LS is gradually enlarged as in the conventional art, the diameter of the sound path LS is increased in accordance with the increase in the diameter of the inner opening end 45a of the sound path LS. It is necessary to narrow the sound path width DS of the inner opening end 45a. When the sound path width DS is narrowed, the ratio of the amount released to the outside (hereinafter referred to as “energy utilization rate”) with respect to the total acoustic energy output from the diaphragm 20 becomes small, so that the efficiency is improved in the mid-low range. The problem that it falls is caused.

  In view of this, in the speaker unit 1 according to the first embodiment, the opening area of the inner opening end 45a of the sound path LS is made larger than the opening area of the output opening end 45b of the sound path LS in order to increase the energy utilization rate. Enlarge. Thereby, energy use efficiency is improved.

  However, if the opening area of the inner opening end 45a of the sound path LS is simply made larger than the opening area of the output opening end 45b of the sound path LS, the efficiency may not be improved. This will be described next.

FIG. 4 shows a curve (schematically shown curve) in which the cross-sectional area of the sound path LS with respect to the distance starting from the inner opening end 45a is plotted.
These curves are derived by regarding the portion corresponding to the phase plug 30 in the through hole 45 of the cover 41 as a truncated cone, and regarding the phase plug 30 as a cone (however, the tip is hemispherical). . The middle point in FIG. 4 indicates the end point of the ring-shaped portion of the sound path LS (the connection point between the ring-shaped portion and the cylindrical portion. The apex of the bolt 33).

  In the curve L2, the sectional area of the inner opening end 45a (hereinafter referred to as “inner opening sectional area”) is slightly larger than the sectional area of the output opening end 45b (hereinafter referred to as “output opening area”). The change of the cross-sectional area of the sound path LS of the speaker unit 1 when set in this way is shown.

  In the curve L2, there is a cross-sectional peak from the inner opening end 45a of the sound path LS to the middle point. That is, the curve L2 indicates that the cross-sectional area of the sound path LS gradually increases and then decreases after exceeding the peak of the cross-sectional area. In the speaker unit 1 having such a sound path LS, the efficiency is lowered. This is because transmission loss of sound waves occurs in a range from the expansion of the cross-sectional area of the sound path LS to the contraction.

  A curve L1 shows a change in the cross-sectional area of the sound path LS of the speaker unit 1 when the inner opening area is larger than the output opening area and the cross-sectional area of the sound path LS is gradually reduced. According to the speaker unit 1 having such a sound path LS, the efficiency is higher than that of the speaker unit 1 having the sound path LS of the curve L2. Since the cross-sectional area of the sound path LS gradually decreases, it is considered that transmission loss of sound waves is suppressed.

  With reference to FIGS. 5-8, the effect by having provided the 1st communicating hole 17a and the 2nd communicating hole 49a in the speaker unit 1 and the effect by gradually reducing the cross-sectional area of the said sound path are demonstrated. In addition, the acoustic characteristic graph shown in FIGS. 5-8 shows the sound pressure with respect to a frequency.

FIG. 5 shows acoustic characteristics SP1 and SP2 of the speaker units of the first reference example and the second reference example.
In the speaker unit of the first reference example, the first communication hole 17a and the second communication hole 49a are not provided, and the inner opening area is smaller than the output opening area. Other configurations are the same as those of the speaker unit 1 described above. That is, the speaker unit of the first reference example is a speaker unit having a conventional structure.

  In the speaker unit of the second reference example, a first communication hole 17a is provided for the speaker unit of the first reference example. That is, in the speaker unit of the second reference example, the first space SA on the back side of the inner ring portion 20a of the diaphragm 20 and the internal space SN of the yoke 13 are communicated with each other through the first communication hole 17a.

  As shown in FIG. 5, the acoustic characteristic SP2 of the speaker unit of the second reference example has higher efficiency than the acoustic characteristic SP1 of the speaker unit of the first reference example in the middle and low sound range (70 Hz to 500 Hz) (arrows). A). This is an effect obtained by providing the first communication hole 17a. However, the acoustic characteristic SP2 of the speaker unit of the second reference example has a lower efficiency than the acoustic characteristic SP1 of the speaker unit of the first reference example in the middle sound range (500 Hz to 1 kHz) (see arrow B). This is thought to be due to the occurrence of a resonance mode.

FIG. 6 shows acoustic characteristics of the speaker units of the first reference example and the third reference example.
The speaker unit of the third reference example is provided with a second communication hole 49a with respect to the speaker unit of the first reference example. That is, in the speaker unit of the third reference example, the second space SB on the back side of the outer ring portion 20b of the diaphragm 20 and the side space SO are communicated with each other through the second communication hole 49a.

  As shown in FIG. 6, the acoustic characteristic SP3 of the speaker unit of the third reference example has higher efficiency than the acoustic characteristic SP1 of the speaker unit of the first reference example in the middle to low range (70 Hz to 500 Hz) (arrows). C). This is an effect of providing the second communication hole 49a. However, the acoustic characteristic SP3 of the speaker unit of the third reference example has a lower efficiency than the acoustic characteristic SP1 of the speaker unit of the first reference example in the middle sound range (500 Hz to 1 kHz) (see arrow D). This is thought to be due to the occurrence of a resonance mode.

FIG. 7 shows the acoustic characteristics of the speaker unit 1 of the first reference example and the first embodiment.
The speaker unit 1 of the first embodiment is provided with a first communication hole 17a and a second communication hole 49a with respect to the speaker unit of the first reference example.

  As shown in FIG. 7, the acoustic characteristic SPA of the speaker unit 1 of the first embodiment has a higher efficiency than the acoustic characteristic SP1 of the speaker unit of the first reference example in the mid-low range (70 Hz to 500 Hz). (Refer to arrow E) In the middle sound range (500 Hz to 1 kHz), a decrease in efficiency is suppressed (see arrow F). That is, according to this configuration, in addition to improving the efficiency of the mid-low range, an effect that does not occur when only one of the first communication hole 17a and the second communication hole 49a is provided (efficiency reduction in the mid-range). Suppression effect).

FIG. 8 shows acoustic characteristics of the speaker units of the first reference example and the second embodiment.
The speaker unit 1 of the second embodiment is provided with the first communication hole 17a and the second communication hole 49a with respect to the speaker unit of the first reference example, and the cross-sectional area of the ring-shaped portion is gradually reduced in the sound path LS. It is configured.

  As shown in FIG. 8, the acoustic characteristic SPB of the speaker unit 1 of the second embodiment has a higher efficiency than the acoustic characteristic SP1 of the speaker unit of the first reference example in the mid-low range (70 Hz to 500 Hz). (Refer to arrow G), efficiency is almost maintained in the middle sound range (500 Hz to 1 kHz) (see arrow H), and higher efficiency than the acoustic characteristic SP1 of the speaker unit of the first reference example in the high sound range (3 kHz to 20 kHz). (See arrow I).

The efficiency improvement in the mid-low range (70 Hz to 500 Hz) is an effect obtained by providing the first communication hole 17a and the second communication hole 49a.
The efficiency improvement in the high sound range (3 kHz to 20 kHz) is an effect due to the configuration in which the cross-sectional area of the sound path LS is gradually reduced.

  The efficiency reduction suppression in the middle sound range (500 Hz to 1 kHz) is comprehensive because the first communication hole 17a and the second communication hole 49a are provided and the cross-sectional area of the sound path LS is gradually reduced. It is considered to be an effect.

According to the first embodiment, the following effects can be obtained.
(1) The speaker unit 1 according to the first embodiment includes at least one first communication hole 17a that communicates the first space SA on the back surface side of the diaphragm 20 with the internal space SN (rear space) of the magnetic circuit 10. And at least one second communication hole 49 a that communicates the second space SB on the back surface side of the diaphragm 20 and the side space SO of the magnetic circuit 10.

  According to this configuration, the first space SA on the back side of the diaphragm 20 and the internal space SN of the magnetic circuit 10 communicate with each other, so that the space on the back side of the diaphragm 20 is expanded. Further, the second space SB on the back surface side of the diaphragm 20 and the side space SO of the magnetic circuit 10 communicate with each other, so that the space on the back surface side of the diaphragm 20 is expanded. Thereby, since the so-called back cavity is enlarged, the acoustic characteristics of the mid-low range of the speaker unit 1 are improved. Moreover, the efficiency fall in a mid range is suppressed as demonstrated above. Further, there is almost no influence in the high sound range, and a slight improvement in efficiency can be obtained.

  (2) In the speaker unit 1, the sound path LS has a link-like portion formed between the through hole 45 provided in the case 40 and the phase plug 30 disposed in the through hole 45. The cross-sectional area of the ring-shaped portion in the sound path LS gradually decreases from the inner opening end 45a toward the output opening end 45b.

  According to this configuration, the inner area of the sound path LS is larger than the sound path LS configured so that the cross-sectional area of the ring-shaped portion in the sound path LS gradually increases from the inner opening end 45a toward the output opening end 45b. The direction opening end 45a is enlarged. For this reason, the energy utilization rate of acoustic energy improves. Further, the transmission loss of the sound path LS is suppressed by the configuration in which the cross-sectional area of the ring-shaped portion in the sound path LS is gradually reduced from the inner opening end 45a toward the output opening end 45b. From these things, the efficiency of the speaker unit 1 improves.

  (3) In the speaker unit 1, a resin sealing member 49 is disposed between the cover 41 and the magnetic circuit 10. The diaphragm 20 is disposed between the cover 41 and the magnetic circuit 10 and inside the sealing member 49. The second communication hole 49 a is provided as a groove in the sealing member 49.

  The resin sealing member 49 is easier to process than the plate 12. For this reason, according to this configuration, the productivity of the speaker unit 1 is improved as compared with the case where the second communication hole 49 a is provided in the plate 12.

  Moreover, since the sealing member 49 has the 2nd communicating hole 49a comprised not as a through-hole but as a groove | channel, it can be shape | molded by resin molding or die-casting. For this reason, it contributes to the productivity improvement of the speaker unit 1.

  (4) In the speaker unit 1, the yoke 13 includes the back plate portion 14 connected to the rear surface of the magnet 11, the peripheral wall portion 16 along the inner peripheral surface of the magnet 11, and the front plate portion that covers the front end of the peripheral wall portion 16. 17. The first communication hole 17 a passes through the front plate portion 17 of the yoke 13. That is, in the case of the outer magnet type speaker unit 1, the first communication hole 17 a is provided in the yoke 13.

(Second Embodiment)
In the first embodiment, the speaker unit 1 having the outer magnet type magnetic circuit 10 has been described. However, the technique described above is also applied to the speaker unit 1 having the inner magnet type magnetic circuit 10. . Hereinafter, the same reference numerals are given to the same components as those of the speaker unit 1 shown in the first embodiment, and the speaker unit 1 will be described.

FIG. 9 shows an example of the speaker unit 1 having an inner magnet type magnetic circuit 10.
The speaker unit 1 includes a magnetic circuit 10, a diaphragm 20, a voice coil 21, a phase plug 30, and a case 40 that accommodates these components. The magnetic circuit 10 includes a ring-shaped magnet 11, a circular plate 112 disposed on the front surface of the magnet 11, and a yoke 113 disposed so as to form a magnetic gap G with respect to the outer peripheral surface 112 c of the plate 112. Is provided.

The yoke 113 has a ring-shaped back plate portion 113 a disposed on the rear surface of the magnet 11 and an outer wall portion 113 b along the outer peripheral surface of the magnet 11.
An inner sealing member 114 for connecting the phase plug 30 is disposed at the center of the front surface of the plate 112. The diameter of the inner sealing member 114 is smaller than the diameter of the center hole 11 a of the magnet 11. A plurality of first communication holes 112a are formed around the inner sealing member 114 in the plate 112 at equal intervals along the circumferential direction. Each first communication hole 112 a allows the space on the back surface side of the inner ring portion 20 a (first space SA) and the internal space SM in the magnet 11 to communicate with each other. The first space SA is partitioned by at least a first portion inside the voice coil 21 of the diaphragm 20, the voice coil 21, and the plate 112 of the magnetic circuit 10. The internal space SM is a concept that belongs to a rear space that exists on the rear side of the front surface of the magnetic circuit 10.

The cover 41 has the same structure as that of the first embodiment, and includes a center portion 42, a circumferential portion 43, and an outer peripheral portion 44 provided around the circumferential portion 43.
A ring-shaped sealing member 49 is disposed between the circumferential portion 43 of the cover 41 and the outer wall portion 113 b of the yoke 113. The sealing member 49 is made of resin.

  Further, a plurality of second communication holes 49 a are provided at equal intervals in the circumferential direction between the sealing member 49 and the outer wall portion 113 b of the yoke 113. Each second communication hole 49 a extends along the radial direction of the sealing member 49 and the outer wall 113 b of the yoke 113. For example, each second communication hole 49 a is configured as a groove in which a part of the surface of the yoke 113 of the sealing member 49 is cut out. Each of the second communication holes 49 a allows the space on the back surface side (second space SB) of the outer ring portion 20 b to communicate with the side space SO in the case 40. The second space SB is partitioned by at least a second portion outside the voice coil 21 of the diaphragm 20, the voice coil 21, and the yoke 113. Other configurations are the same as those of the speaker unit 1 shown in the first embodiment.

  As described above, in the case of the inner magnet type speaker unit 1, each first communication hole 112 a is provided in the plate 112, unlike the outer magnet type speaker unit 1. Each of the second communication holes 49 a is provided as a groove in the sealing member 49 as in the outer magnet type speaker unit 1. Also with this configuration, the effect according to the above (1) described in the first embodiment can be obtained.

  Further, in the speaker unit 1 having the inner-magnet-type magnetic circuit 10, the sound path LS is configured so that the cross-sectional area of the sound path LS is gradually reduced. The effect 2) can be obtained.

(Other embodiments)
-In 1st Embodiment, although the front-plate part 17 and the connection part 18 are integrally formed, these can be comprised as another member. In this case, it is preferable that the separated connecting portion 18 and the intervening component 19 (seal member) are integrally formed. According to such a configuration, since the structure of the yoke 13 is simplified, there is no increase in the number of parts, so that the production efficiency is improved.

  The sound path LS shown in the first and second embodiments is an example, and the structure of the sound path LS is not limited to this. For example, the sound path LS can be configured in a ring shape from the inner opening end 45a to the output opening end 45b of the sound path LS. Further, the cylindrical portion may be configured such that the cross-sectional area gradually increases toward the output opening end 45b, or may be configured so that the cross-sectional area gradually decreases toward the output opening end 45b. Good.

  -In 1st and 2nd embodiment, each 2nd communicating hole 49a is arrange | positioned between the sealing member 49 and the plate 12, and each 2nd communicating hole 49a cuts off a part of sealing member 49 However, the configuration of each second communication hole 49a is not limited to this. For example, each second communication hole 49 a can be configured as a through hole that penetrates the sealing member 49.

-The technique shown in 1st and 2nd embodiment is applied to a speaker.
Such a speaker is provided with the speaker unit 1 so that the efficiency of the mid-low range is improved.

  In the first and second embodiments, the speaker unit 1 includes the plurality of first communication holes 17a and the plurality of second communication holes 49a. However, the speaker unit 1 includes at least one first communication hole 17a and at least one second communication hole. The number of the first communication holes 17a and the number of the second communication holes 49a are not particularly limited as long as the communication holes 49a are provided.

  DESCRIPTION OF SYMBOLS 1 ... Speaker unit, 10 ... Magnetic circuit, 11 ... Magnet, 11a ... Center hole, 12 ... Plate, 12a ... Center hole, 12b ... Inner peripheral surface, 13 ... Yoke, 14 ... Back plate part, 15 ... Center part, 15a DESCRIPTION OF SYMBOLS ... Outer peripheral surface, 16 ... Peripheral wall part, 17 ... Front plate part, 17a ... 1st communicating hole, 18 ... Connection part, 19 ... Interposition part, 20 ... Diaphragm, 20a ... Inner ring part, 20b ... Outer ring part, 21 DESCRIPTION OF SYMBOLS ... Voice coil, 30 ... Phase plug, 31 ... Base part, 32 ... Main body part, 32a ... Side surface, 33 ... Bolt, 40 ... Case, 41 ... Cover, 42 ... Center part, 43 ... Circumferential part, 44 ... Outer peripheral part, 45 ... through hole, 45a ... inward opening end, 45b ... output opening end, 46 ... case body, 47 ... side wall, 48 ... bottom wall, 49 ... sealing member, 49a ... second communication hole, 112 ... plate, 112a ... 1st communication hole, 112c ... Circumferential surface, 113 ... York, 113a ... backplate portion, 113b ... outer wall portion, 114 ... inner sealing member.

Claims (9)

A speaker unit,
A ring-shaped diaphragm;
A ring-shaped voice coil provided along the circumferential direction of the diaphragm at a radial intermediate portion of the diaphragm;
A ring-shaped magnetic circuit having a magnetic gap through which the voice coil is inserted;
E Bei and a case of forming the rear space provided behind than the sound path between the diaphragm for guiding the sound emitted from the diaphragm to the outside,
A ring-shaped first space is defined by at least a first portion inside the diaphragm with respect to the voice coil, the voice coil, and the magnetic circuit,
A ring-shaped second space is defined by at least a second portion outside the voice coil of the diaphragm, the voice coil, and the magnetic circuit,
The rear space includes an inner space radially inward of the magnetic circuit, a side space radially outer of the magnetic circuit, and a bottom space connecting the inner space and the side space,
A speaker unit comprising: at least one first communication hole that communicates the first space and the internal space; and at least one second communication hole that communicates the second space and the side space . The speaker unit is
Further comprising a phase plug provided on the diaphragm,
The sound path includes a ring-shaped portion formed between the case and the phase plug,
The speaker unit according to claim 1, wherein the ring-shaped portion of the sound path has a cross-sectional area that gradually decreases from an inner opening end toward an output opening end. The case includes a cover having the sound path, and a case body that houses the magnetic circuit,
The speaker unit includes a resin sealing member provided between the cover and the magnetic circuit,
The diaphragm is disposed inside the sealing member between the cover and the magnetic circuit,
The speaker unit according to claim 1, wherein the at least one second communication hole includes a groove or a through hole formed in the sealing member. The magnetic circuit includes a ring-shaped magnet disposed on a radially outer side of the diaphragm than the voice coil, a ring-shaped plate provided on a surface of the magnet facing the diaphragm, and the plate And a yoke arranged to form the magnetic gap with respect to the inner peripheral surface of
The yoke includes a back plate portion provided on a surface of the magnet opposite to the plate, a peripheral wall portion along an inner peripheral surface of the magnet, and a front plate portion covering a front end of the peripheral wall portion. ,
The speaker unit according to any one of claims 1 to 3, wherein the first communication hole penetrates the front plate portion of the yoke. The magnetic circuit includes a ring-shaped magnet disposed radially inward of the diaphragm relative to the voice coil, a circular plate provided on a surface of the magnet facing the diaphragm, and the magnet And a yoke disposed on a surface opposite to the plate and arranged to form the magnetic gap with respect to an outer peripheral surface of the plate,
The speaker unit according to any one of claims 1 to 3, wherein the first communication hole penetrates the plate. The case houses the diaphragm, the voice coil, and the magnetic circuit,
The rear space is partitioned by at least a portion of the magnetic circuit opposite to the diaphragm and the case.
The speaker unit according to any one of claims 1 to 5, wherein the side space is partitioned by at least a side portion of the magnetic circuit and the case. The speaker unit is provided between the magnetic circuit and the case, and includes a sealing member that partitions the second space and the side space,
The speaker unit according to claim 6, wherein the at least one second communication hole includes a groove or a through hole formed in the sealing member so as to communicate the second space and the side space. A speaker unit,
A ring-shaped diaphragm;
A ring-shaped voice coil provided along the circumferential direction of the diaphragm at a radial intermediate portion of the diaphragm;
A magnetic circuit having a magnetic gap through which the voice coil is inserted;
A case having a sound path for guiding the sound emitted from the diaphragm to the outside;
A phase plug provided on the diaphragm ;
The sound path includes a ring-shaped portion formed between the case and the phase plug,
The ring unit of the sound path has a cross-sectional area that gradually decreases from an inner opening end toward an output opening end. A speaker provided with the speaker unit as described in any one of Claims 1-8 .

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