JP5920160B2 - Speaker - Google Patents

Description

  The present invention relates to a loudspeaker, and more particularly, to a loudspeaker having a heat dissipation structure for suppressing a temperature rise due to heat generated by vibration.

In the speaker, heat is generated when an input audio signal is converted into mechanical vibration as an audio output.
If this heat accumulates and the temperature of the magnetic circuit, voice coil, etc. becomes excessively high, there is a concern that problems such as peeling of the adhesive used to fix the members and burning of the voice coil may occur.
For this reason, various speakers having a heat dissipation structure have been proposed in order to prevent the magnetic circuit, voice coil, and the like from becoming excessively hot.

As an example, there is a speaker described in Patent Document 1.
The speaker described in Patent Document 1 has a heat dissipating structure in which an air intake hole and an exhaust hole communicating with an external space and an internal space of the speaker are formed in the center pole so as to penetrate in the drive axis direction. Is provided with a valve for limiting the flow of air passing through the speaker in the direction of intake into the speaker, and a valve for limiting in the direction of exhaust to the outside at the exhaust hole.

  With this heat dissipation structure, intake and exhaust are alternately performed from the intake and exhaust holes as the diaphragm vibrates, replacing the hot air in the internal space and the room temperature air in the external space, thereby replacing the magnetic circuit of the speaker. It is said that the temperature rise such as can be suppressed.

JP-A-8-102994 (paragraph numbers: 0024 to 0027, FIG. 2)

By the way, in the speaker described in Patent Document 1, the space opened on the speaker inner side of the intake hole and the exhaust hole is a space generally surrounded by a center pole, a voice coil bobbin, and a center cap (hereinafter referred to as an internal space A). Called).
Therefore, when the diaphragm including the center cap vibrates, most of the air that replaces the air in the external space becomes hot air in the internal space A, and the space connected to the internal space A by a narrow flow path, that is, the voice coil It is difficult to say that sufficient replacement of the hot air in the magnetic circuit internal space (see paragraph No. 0025 of Patent Document 1) where the heat is generated by heat generation and the air in the external space is performed.

On the other hand, the position where the intake hole and the exhaust hole are opened in the external space of the speaker is in the outer surface of the center pole, and the holes are relatively close to each other.
Therefore, even when hot air in the internal space A is discharged from the exhaust hole to the external space, there is a possibility that a part of the discharged hot air is again sucked from the intake hole.
In particular, when the installation position of the speaker is such that the intake hole is above the exhaust hole, it can happen that most of the outside air that has been sucked becomes hot air.

  Therefore, it is considered that the speaker described in Patent Document 1 has sufficient room for further improving the heat dissipation effect of the heat dissipation structure for suppressing an excessively high temperature such as a magnetic circuit.

  Therefore, the problem to be solved by the present invention is to provide a speaker that can dissipate heat generated in the process of converting an audio signal into mechanical vibration to the outside in order to suppress excessive heating of a magnetic circuit or the like. It is in.

In order to solve the above problems, the present invention has any one of the following configurations 1) to 5 ).
1) a diaphragm,
A magnetic circuit;
A voice coil arranged to vibrate integrally with the diaphragm in the gap of the magnetic circuit;
A speaker with
A ventilation path formed including the gap in the middle;
A flow restricting portion that is provided in the ventilation path and restricts the flow rate in one direction of the passing air to be smaller than the flow rate in the other direction;
A frame having one side integrated with the magnetic circuit, an outer peripheral edge of the diaphragm connected to the other side via an edge, and an opening between the one side and the other side ;
Equipped with a,
The magnetic circuit has a through hole that communicates the internal space and the external space of the speaker;
One end side of the ventilation path communicates with the external space through the opening of the frame, and the other end side communicates with the external space through the through hole of the magnetic circuit. It is a speaker.
2 ) The speaker according to 1 ), wherein the flow restricting portion restricts a flow rate of air flowing through the through hole of the magnetic circuit.
3 ) The speaker according to 1 ), wherein the flow restricting portion restricts a flow rate of air flowing through the opening of the frame.
4 ) The speaker according to any one of 1) to 3 ), wherein the flow restricting portion is detachably provided.
5 ) The speaker according to any one of 1 to 4 ), wherein the flow restriction unit is capable of adjusting a ratio of the flow rate of the air in one direction and the flow rate in the other direction. is there.

  According to the present invention, it is possible to obtain an effect that heat generated in the process of converting an audio signal into mechanical vibration can be radiated well to the outside.

It is sectional drawing for demonstrating Example 1 of the speaker which concerns on embodiment of this invention. 3 is an enlarged cross-sectional view of a main part in Example 1. FIG. FIG. 3 is a perspective exploded view of a main part in the first embodiment. FIG. 3 is a first cross-sectional view for explaining an operation in the first embodiment. FIG. 6 is a second cross-sectional view for explaining the operation of the first embodiment. It is 1st sectional drawing for demonstrating operation | movement of Example 2 of the speaker which concerns on the form of the Example of this invention. FIG. 10 is a second cross-sectional view for explaining the operation of the second embodiment. It is 1st sectional drawing for demonstrating operation | movement of Example 3 of the speaker which concerns on the form of the Example of this invention. FIG. 10 is a second cross-sectional view for explaining the operation of the third embodiment. It is 1st sectional drawing for demonstrating operation | movement of Example 4 of the speaker which concerns on the form of the Example of this invention. FIG. 10 is a second cross-sectional view for explaining the operation of the fourth embodiment. It is the front view and sectional drawing which show Example 5 of the speaker which concerns on the form of the Example of this invention. FIG. 10 is a partial cross-sectional view for explaining a main part of a fifth embodiment. FIG. 10 is a partial cross-sectional view for explaining a first modification. 11 is a cross-sectional view for explaining the operation of Modification 2. FIG. 10 is a cross-sectional view for explaining a main part of Modification 2. FIG. It is a schematic diagram of the structure of Examples 1-5.

  A speaker according to an embodiment of the present invention will be described with reference to FIGS.

<Example 1>
FIG. 1 is a cross-sectional view for explaining the speaker 51 of the first embodiment. Each direction before and after in the following description is defined by a direction indicated by an arrow in FIG.
The speaker 51 includes a frame 1 that forms a step-shaped annular outer peripheral wall whose diameter decreases toward the rear side with the axis CL1 as the center, a vibration part SD that is attached to the frame 1 so as to vibrate in the front-rear direction, And a magnetic circuit unit ZK that is attached to the rear part and converts an input electric signal into mechanical vibration in cooperation with a voice coil 6 (described later) of the vibration unit SD.
The frame 1 is made of, for example, metal, and a plurality of openings 1c are formed on the outer peripheral wall at predetermined intervals in the circumferential direction.
An annular damper holder 7 is fixed at a position on the inner surface of the frame 1 that substantially corresponds to the opening 1c in the front-rear direction. A plurality of openings 7 a are formed in the damper holder 7 at predetermined intervals in the circumferential direction.
The opening 1c of the frame 1 and the opening 7a of the damper holder 7 may be provided at positions and ranges corresponding to each other in the circumferential direction.

  The vibration part SD is formed in a substantially mortar shape centered on the axis CL1 and an annular edge 2 to which an outer peripheral side edge is attached to a flange 1a formed in an annular shape at the front side end of the frame 1, A diaphragm 3 whose outer peripheral edge is connected to the inner peripheral edge of the edge 2 is attached to the diaphragm 3 so as to close a circular opening 3a formed at the center thereof, and the cross-sectional shape is forward A center cap 4 formed in a projecting arc shape, a voice coil bobbin 5 formed in a cylindrical shape centering on the axis line CL1 and having the front end portion inserted through the opening 3a, and a voice coil bobbin 5 It is formed in a bellows shape by repeating a voice coil 6 wound in a predetermined range from the rear end side to the front and a substantially disc-shaped concentric uneven rib, and an outer peripheral edge portion is fixed to the damper holder 7. It is configured to have a damper 8 that inner peripheral edge portion is fixed to the distal end side outer peripheral surface of the voice coil bobbin 5, a.

  In this configuration, the diaphragm 3 can vibrate in the front-rear direction with respect to the frame 1 through the edge 2 and the damper 8 together with the center cap 4 integrated with the diaphragm 3, the voice coil bobbin 5 and the voice coil 6. It is supported.

  The lead of the voice coil 6 is connected to a connection terminal 10 fixed to the frame 1 via a fiber-coated electric wire 9. Accordingly, an input audio signal coming from the outside is supplied to the voice coil 6 via the connection terminal 10 and the fiber-coated electric wire 9.

The magnetic circuit unit ZK includes a ring-shaped magnet 11, a ring-shaped flat plate top plate 12 fixed to the front side of the magnet 11, and a pole piece 13a inserted from the rear side into the central opening of the magnet 11 and the top plate 12. A yoke 13 fixed to the rear side of the magnet 11 having a flange portion 13b formed so as to project outward in the radial direction on the rear end side of the pole piece 13a.
The magnetic circuit portion ZK is integrated with the rear end portion 1b of the frame 1 by fixing the top plate 12 with screws or the like.

In the above-described configuration, the voice coil 6 is disposed in the gap Gp, which is a narrow annular space between the pole piece 13a and the top plate 12, so as not to contact the pole piece 13a and the top plate 12.
Therefore, when an AC input audio signal is supplied to the voice coil 6 via the connection terminal 10, the voice coil 6 vibrates in the front-rear direction due to the Lorentz force generated corresponding to the input audio signal. That is, the voice coil 6, the voice coil bobbin 5 and the diaphragm 3 integral with the voice coil 6 vibrate integrally in the front-rear direction.
In conjunction with this, the edge 2 connected to the diaphragm 3 and the damper 8 connected to the voice coil 6 also move in the front-rear direction.

The damper 8, together with the edge 2, supports the diaphragm 3 so that the voice coil 6 does not contact the top plate 12 and the pole piece 13 a in the gap Gp, and applies predetermined braking to the vibration.
Moreover, the presence or absence of the air permeability of the damper 8 and the degree of ventilation when the air permeability is provided are not limited.

In the speaker 51, the pole piece 13a is formed with a through hole 13a1 along the front-rear direction. The through hole 13a1 is, for example, a hole centered on the axis line CL1.
A detailed structure near the opening 13a2 on the front side in the through hole 13a1 will be described with reference to FIGS.
2 is an enlarged cross-sectional view of the vicinity of the opening 13a2, and FIG. 3 is a perspective exploded view of the structure of the vicinity of the opening 13a2.

The opening 13a2 of the through hole 13a1 is open to the bottom surface 13a5 of the recess 13a4 that is circularly recessed with respect to the front surface 13a3 of the pole piece 13a.
The front surface 13a3 and the bottom surface 13a5 are connected by an inclined portion 13a6 that decreases in diameter toward the bottom surface 13a5.
The valve regulating member 14 and the valve member 15 are attached to the bottom surface 13a5 so as to overlap each other with the valve member 15 as the front side. Hereinafter, the valve regulating member 14 and the valve member 15 are collectively referred to as a valve 16.

The valve regulating member 14 has an annular outer frame portion 14k and a net portion 14a supported by the outer frame portion 14k. The mesh part 14a has sufficient air permeability, and the form of the mesh is, for example, a plain weave.
In the valve restricting member 14, the diameter of the mesh portion 14a is set to be equal to or larger than the inner diameter of the through hole 13a1. Moreover, the net | network part 14a has sufficient clearance gap between weaves so that air can distribute | circulate freely in any direction of back and front. The weaving mode of the net is not limited to the plain weave.
The material of the valve restricting member 14 is not limited to metal in both the outer frame portion 14k and the net portion 14a. Different materials may be used. Examples of materials other than metal are resin, woven fabric, and non-woven fabric.
The net portion 14a may be a so-called punching metal (metal or resin resin) instead of the net. Moreover, the sheet-like woven fabric or nonwoven fabric which has air permeability may be sufficient.

  The valve member 15 has an annular outer frame portion 15k, and a flap 15b extending from the outer frame portion 15k toward the center and divided into a plurality of pieces by a plurality of radial cuts 15a. In this example, the cuts 15a are, for example, cross-shaped and the number of flaps 15b is four. The shape of the cut 15a and the number of the flaps 15b are not limited.

The valve member 15 is formed of a flexible material (for example, silicone rubber).
Each of the flaps 15b formed to extend from the annular outer frame portion 15k in the inner diameter direction has a sufficiently small thickness. Specifically, the thickness of the flap 15b is set so as to allow the flow to be easily deformed with respect to a slight air flow that attempts to pass through the valve member 15 in consideration of the characteristics related to the material. Yes.
Therefore, in FIG. 2, for example, when the pressure on the through-hole 13a1 side (rear side) becomes high and air is about to flow forward through the inside of the through-hole 13a1, the air is the mesh portion of the valve regulating member 14. After passing through 14a, the flap 15b of the valve member 15 can be pushed and bent as shown by a two-dot chain line to form a gap sufficient for air flow. Thereby, the air passes through the valve regulating member 14 and the valve member 15 and escapes to the front side. That is, the air flow from the rear to the front (see the white arrow) is allowed in the valve member 15.

On the other hand, when the pressure on the front side becomes higher than the through-hole 13a1 and the air tries to flow rearward inside the through-hole 13a1, the air first tries to deform the flap 15b to the rear side. To do.
However, since the mesh portion 14a is disposed close to the rear side of the flap 15b, the flap 15b abuts against the mesh portion 14a when it is slightly deformed and cannot be further deformed.
Therefore, almost no gap is formed, and the air flow from the front side to the rear side in the through hole 13a1 is substantially prohibited.
Thus, the valve 16 operates so as to restrict the direction of the air flow in the through hole 13a1 in one direction by the cooperation of the valve restricting member 14 and the valve member 15.

The air flow in the driving state (sound output state) of the speaker 51 provided with the valve 16 will be described in detail with reference to FIGS. 4 and 5.
FIG. 4 is a cross-sectional view showing a state in which the vibration part SD has moved forward with respect to the reference state in the driving state of the speaker 51, and FIG. 5 shows a state in which the vibration part SD has moved backward with respect to the reference state. It is sectional drawing shown. The air flow is indicated by the arrows on the black triangular head. Here, the reference state in which the vibration part SD is not moving is the state shown in FIG.

When an AC audio signal flows through the voice coil 6, the speaker 51 reciprocates (vibrates) in the front-rear direction with respect to the position of the reference state according to the time waveform of the signal.
When moving to the front side from the reference state by this vibration, the volume of the internal space SP1 surrounded by the center cap 4, the diaphragm 3, the voice coil bobbin 5, and the pole piece 13a increases as compared with the reference state. .
The flow path connecting the internal space SP1 and the external space SP includes a gap Gp, a flow path passing through the opening 7a of the damper holder 7 and the opening 1c of the frame 1 (hereinafter referred to as a gap flow path), a valve 16 and a through hole. There are two types of flow paths (hereinafter referred to as through-hole flow paths) passing through the holes 13a1.
Here, when the volume of the space SP1 increases due to the forward movement of the vibration part SD, the pressure in the internal space SP1 becomes negative with respect to the external space SP, so that air inflow from the external space SP to the internal space SP1 is illustrated. It is done.
The flow path resistance of the gap flow path at this time is that the flow path cross-sectional area is small and the valve 16 held by the through-hole flow path allows air to flow forward. It is much larger than resistance.
Therefore, the air on the rear side of the speaker 51 in the external space SP flows into the internal space SP1 through the through-hole channel while deforming the flap 15b of the valve member 15 to open to the front side and forming a channel. . That is, it flows into the internal space SP1 through the through hole 13a1, the valve regulating member 14, and the valve member 15 (see the black triangular head arrow).

The state which moved to the back side with respect to the reference | standard state of the vibration part SD in this structure is shown in FIG.
In the state of moving to the rear side, the volume of the internal space SP1 is reduced as compared with the reference state, and the pressure of the internal space SP1 becomes positive with respect to the external space SP to move from the internal space SP1 to the external space SP. Air outflow.
At this time, the flow path resistance of the gap flow path is smaller than the flow path resistance of the through-hole flow path although the flow path resistance of the gap flow path is small because the valve 16 held by the through-hole path prohibits the backward flow of air. It is getting smaller.
Therefore, the air in the internal space SP1 urges the flap 15b of the valve member 15 toward the rear net 14a, while passing through the gap Gp and from the opening 1c of the frame 1 to the side external space SP. Spill to

When air passes through the gap Gp, it first flows into the gap between the outer peripheral surface of the pole piece 13a and the inner peripheral surface of the voice coil bobbin 5 from the internal space SP1 and escapes backward.
Next, when the rear end face of the voice coil bobbin 5 is crossed outward, the flow direction is reversed forward, and the gap between the outer peripheral face of the voice coil 6 and the inner peripheral face of the magnet 11 is moved forward. Furthermore, it passes through a gap between the outer peripheral surface of the voice coil 6 and the top plate 12, and reaches a space on the rear side of the damper 8 (hereinafter also referred to as a damper rear space SP2).
As the vibration continues, the air flow shown in FIGS. 4 and 5 is performed alternately and continuously.

As described above, in the speaker 51, the positions of the intake holes and the exhaust holes are on the rear surface side and the side surface side with respect to the frame 1, respectively, and both positions are sufficiently separated.
Therefore, hot air does not flow into the internal space SP1, and since the flowing outside air is always at room temperature, a good heat dissipation effect can be obtained.
In addition, the direction of the air flow generated along with the back-and-forth movement of the vibration part SD is determined in a substantially constant direction by the valve 16. That is, the route includes the through hole 13a1 of the pole piece 13a, the internal space SP1, the gap Gp, the damper rear space SP2, the opening 7a of the damper holder 7, and the opening 1c of the frame 1.
Strictly speaking, in the damper rear space SP2, a reciprocating air flow can be generated as the damper 8 moves back and forth. However, the air flow direction in the gap Gp in the region where the temperature rises remarkably is almost completely constant. It is fixed and maintained.

Thereby, normal temperature air flowing in from the outside intermittently is supplied to the gap Gp, and when the normal temperature air passes through the gap Gp, the temperature is raised by sufficiently removing the heat of the voice coil 6 and the vicinity thereof, Since the hot air that has been heated is discharged to the outside without returning to the gap Gp, the speaker 51 exhibits high heat dissipation efficiency.
In addition, an increase in the flow rate due to the air flowing into the narrow gap Gp also contributes to the improvement of the heat dissipation efficiency.

<Example 2>
6 and 7 are cross-sectional views for explaining the operation of the speaker 52 of the second embodiment. 6 is a cross-sectional view showing a state in which the vibration part SD has moved forward relative to the reference state in the driving state of the speaker 52, and FIG. 7 shows a state in which the vibration part SD has moved backward relative to the reference state. It is sectional drawing shown. 6 and 7 are comparable diagrams corresponding to FIGS. 4 and 5, respectively.

The speaker 52 is different from the speaker 51 of the first embodiment in the attachment position of the valve 16 and the front-rear direction.
Specifically, in the speaker 52, the valve 16 is provided at the rear end of the through hole 13a1 of the pole piece 13a. Further, the valve 16 is attached so that the valve regulating member 14 is on the front side (inner space SP1 side) and the valve member 15 is on the rear side (outer space SP side).

More specifically, a recessed portion 13a8 having a larger diameter than the through hole 13a1 is formed at the rear end of the through hole 13a1. An opening 13a7 communicating with the external space SP in the through hole 13a1 is provided on the bottom surface 13a9 of the recess 13a8.
The valve 16 is attached to the bottom surface 13a9.
As described above, since the valve restricting member 14 is disposed on the front side of the valve member 15, the flow of air that attempts to enter the through hole 13a1 from the rear external space SP is prohibited and penetrates from the internal space SP1. The flow of air flowing out to the external space SP through the hole 13a1 is allowed.

In the configuration of the speaker 52, the flow path connecting the internal space SP1 and the external space SP passes through the gap Gp, the opening 7a of the damper holder 7, and the opening 1c of the frame 1 as in the speaker 51 of the first embodiment. There are two types: a gap channel and a through-hole channel passing through the valve 16 and the through-hole 13a1.
Here, as shown in FIG. 6, when the vibration part SD is moved forward with respect to the position of the reference state, the volume of the internal space SP <b> 1 increases from the volume of the reference state, and the volume of the internal space SP <b> 1 is increased. The pressure becomes negative with respect to the external space SP, so that air can flow into the internal space SP1 from the external space SP.
At this time, the valve 16 held by the through hole path prohibits the flow of air from the external space SP into the through hole 13a1, so that the flow path resistance of the gap flow path penetrates though the flow path cross-sectional area is small. It is smaller than the channel resistance of the hole channel.
Therefore, the air on the rear side of the speaker 52 in the external space SP urges the flap 15b of the valve member 15 toward the mesh portion 14a on the front side, while the air on the side of the speaker 52 is the opening of the frame 1. From the part 1c, it flows into the damper rear space SP2 through the opening 7a of the damper holder 7, and further flows into the internal space SP2 through the gap Gp (see black triangle head arrow).

The state which moved to the back side with respect to the reference | standard state of the vibration part SD in this structure is shown in FIG.
In the state of moving to the rear side, the volume of the internal space SP1 is reduced as compared with the reference state, and the pressure of the internal space SP1 becomes positive with respect to the external space SP to move from the internal space SP1 to the external space SP. Air outflow.
At this time, in addition to the small cross-sectional area of the gap channel, the valve 16 held by the through-hole channel allows air to flow backward, that is, to allow air outflow to the external space SP through the through-hole 13a1, The channel resistance of the gap channel is much larger than the channel resistance of the through-hole channel.
Therefore, the air in the internal space SP1 flows out through the through-hole flow path to the external space SP on the rear side while deforming the flap 15b of the valve member 15 to open to the rear side to form a flow path. That is, it flows out through the through hole 13a1, the valve restricting member 14, and the valve member 15 to the external space SP on the rear side (see the black triangular head arrow).
As the vibration continues, the air flow shown in FIGS. 6 and 7 is performed alternately and continuously.

As described above, in the speaker 52, the positions of the intake holes and the exhaust holes are respectively on the side surface side and the rear surface side with respect to the frame 1, and the positions are sufficiently separated from each other.
Accordingly, hot air does not flow into the internal space SP1, and since the flowing outside air is always at room temperature, a good heat dissipation effect can be obtained.
In addition, the direction of the air flow generated with the longitudinal movement of the vibration part SD is determined in a substantially constant direction. That is, the route includes the opening 1c of the frame 1, the opening 7a of the damper holder 7, the damper rear space SP2, the gap Gp, the internal space SP1, and the through hole 13a1 of the pole piece 13a.
Strictly speaking, in the damper rear space SP2, a reciprocating air flow can be generated as the damper 8 moves back and forth. However, the air flow direction in the gap Gp in the region where the temperature is significantly increased is almost completely constant. It is fixed and maintained.

  As a result, room temperature air intermittently flowing from the outside is supplied to the gap Gp, and when the room temperature air passes through the gap Gp, the heat is taken away from the voice coil 6 and the vicinity thereof, and the temperature rises. Since the hot air thus formed is discharged to the outside without returning to the gap Gp again, the speaker 52 exhibits high heat dissipation efficiency.

<Example 3>
8 and 9 are cross-sectional views for explaining the operation of the speaker 53 of the third embodiment. FIG. 8 is a cross-sectional view showing a state in which the vibration part SD has moved forward relative to the reference state in the driving state of the speaker 53, and FIG. 9 shows a state in which the vibration part SD has moved backward relative to the reference state. It is sectional drawing shown. 8 and 9 are comparable diagrams corresponding to FIGS. 4 and 5, respectively.

The speaker 53 differs from the speakers 51 and 52 of the first and second embodiments in that the valve 16 is attached at the center cap 4 and the through hole 13a1 of the pole piece 13a is not formed.
As shown in FIG. 8, the center cap 4 of the speaker 53 has a flat seat 4a at the center. An opening 4b is formed in the center of the seat 4a. The shape of the opening 4b is, for example, a circle.
An annular recess 4c is formed on the outer side in the radial direction of the seat 4a to improve the strength.
The valve 16 is attached to a position corresponding to the opening 4b on the rear surface (surface on the pole piece 13a side) side of the seat portion 4a. Further, the valve 16 is attached so that the valve regulating member 14 is on the front side (external space SP side) and the valve member 15 is on the rear side (internal space SP1 side).
Therefore, the flow of air trying to enter the internal space SP1 from the front external space SP through the opening 4b is allowed, and the flow of air trying to flow out from the internal space SP1 to the external space SP through the opening 4b is prohibited. It has come to be.

In the configuration of the speaker 53, since the through hole 13a1 is not formed in the pole piece 13a in the flow path connecting the internal space SP1 and the external space SP, the gap Gp, the opening 7a of the damper holder 7, and the frame 1 The gap flow path passing through the opening 1 c and the center cap passage passing through the valve 16 and the opening 4 b of the center cap 4.
Here, as shown in FIG. 8, when the vibration part SD is moved forward with respect to the position of the reference state, the volume of the internal space SP1 increases more than the volume of the reference state, and the volume of the internal space SP1 is increased. The pressure becomes negative with respect to the external space SP, so that air can flow into the internal space SP1 from the external space SP.
At this time, in addition to the small cross-sectional area of the gap channel, the valve 16 held by the center cap channel allows the air to flow backward (inflow into the internal space SP1). The channel resistance of the gap channel is much larger than the channel resistance.
Therefore, the air in the external space SP on the front side of the speaker 53 flows into the internal space SP1 through the center cap flow path while deforming the flap 15b of the valve member 15 so as to form a flow path by opening the flap 15b rearward. . That is, it flows into the internal space SP1 through the opening 4b, the valve restricting member 14, and the valve member 15 (see the black triangular head arrow).

The state which moved to the back side with respect to the reference | standard state of the vibration part SD in this structure is shown in FIG.
In the state of moving to the rear side, the volume of the internal space SP1 is reduced as compared with the reference state, and the pressure of the internal space SP1 becomes positive with respect to the external space SP to move from the internal space SP1 to the external space SP. Air outflow.
At this time, since the valve 16 included in the center cap path prohibits the forward flow from the internal space SP1 to the external space SP, the flow path resistance of the gap flow path is small even though the flow path cross-sectional area is small. It is smaller than the flow path resistance.
Therefore, the air in the internal space SP1 urges the flap 15b of the valve member 15 to the mesh part 14a on the front side, while passing through the gap Gp, the opening 7a of the damper holder 7, and the opening 1c of the frame 1. And flows into the external space SP on the side (see the black triangle head arrow).
As the vibration continues, the air flow shown in FIGS. 8 and 9 is performed alternately and continuously.

As described above, in the speaker 53, the positions of the intake holes and the exhaust holes are respectively on the front side and the side surface side with respect to the frame 1, and the positions are sufficiently separated from each other.
Therefore, hot air does not flow into the internal space SP1, and since the flowing outside air is always warm, a good heat dissipation effect can be obtained.
In addition, the direction of the air flow generated with the longitudinal movement of the vibration part SD is determined in a substantially constant direction. That is, the route includes the opening 4b of the center cap 4, the internal space SP1, the gap Gp, the damper rear space SP2, the opening 7a of the damper holder 7, and the opening 1c of the frame 1.
Strictly speaking, in the damper rear space SP2, a reciprocating air flow can be generated as the damper 8 moves back and forth. However, the flow direction in the gap Gp in the region where the temperature is significantly increased is almost completely fixed. Maintained.

  As a result, room temperature air intermittently flowing from the outside is supplied to the gap Gp, and when passing through the gap Gp, the heat is raised by taking away the heat of the voice coil 6 and the vicinity thereof, and the heated hot air is Since it is discharged to the outside without returning to the gap Gp again, high heat dissipation efficiency is exhibited.

<Example 4>
10 and 11 are cross-sectional views for explaining the operation of the speaker 54 of the fourth embodiment. FIG. 10 is a cross-sectional view showing a state in which the vibration part SD has moved forward with respect to the reference state in the driving state of the speaker 54, and FIG. 11 shows a state in which the vibration part SD has moved backward with respect to the reference state. It is sectional drawing shown. 10 and 11 are comparable diagrams corresponding to FIGS. 8 and 9, respectively.

The speaker 54 allows the flow of air flowing from the inner space SP1 toward the outer space SP from the inner surface to the outer surface with respect to the speaker 53 of the third embodiment. However, it is different in that the reverse flow is prohibited.
As shown in FIG. 10, the center cap 4 of the speaker 54 has a recess 4d at the center. The bottom surface 4d1 of the recess 4d is a flat surface, and an opening 4e is formed at the center of the bottom surface 4d1. The shape of the opening 4e is, for example, a circle.
The valve 16 is attached to a position corresponding to the opening 4e on the front surface (surface on the external space SP side) side of the bottom surface 4d1.
The valve 16 is attached so that the valve regulating member 14 is on the rear side and the valve member 15 is on the front side.
Therefore, the flow of air trying to enter the internal space SP1 from the front external space SP through the opening 4e is prohibited, and the flow of air trying to flow out from the internal space SP1 to the external space SP through the opening 4e is allowed. It has come to be.

In the configuration of the speaker 54, since the through hole 13a1 is not formed in the pole piece 13a in the flow path connecting the internal space SP1 and the external space SP, the gap Gp, the opening 7a of the damper holder 7, and the frame 1 The gap flow path passing through the opening 1 c and the center cap passage passing through the valve 16 and the opening 4 e of the center cap 4.
Here, as shown in FIG. 10, when the vibration unit SD is moved forward with respect to the reference state position, the volume of the internal space SP1 increases from the reference state volume, and the internal space SP1 The pressure becomes negative with respect to the external space SP, so that air can flow into the internal space SP1 from the external space SP.
At this time, since the valve 16 held by the center cap path prohibits the flow of air backward (inflow into the internal space SP1), the flow path resistance of the gap flow path is small even though the flow path cross-sectional area is small. It is smaller than the channel resistance of the road.
Therefore, the air on the front side of the speaker 54 in the external space SP urges the mesh portion 14 a on the rear side with respect to the flap 15 b of the valve member 15, while the air on the side of the speaker 54 is an opening of the frame 1. It flows into the damper rear space SP2 from 1c, and further flows into the internal space SP2 through the gap Gp (see black triangle head arrow).

FIG. 11 shows a state in which the vibration part SD in this configuration has moved rearward with respect to the reference state.
In the state of moving to the rear side, the volume of the internal space SP1 is reduced as compared with the reference state, and the pressure of the internal space SP1 becomes positive with respect to the external space SP to move from the internal space SP1 to the external space SP. Air outflow.
At this time, in addition to the small cross-sectional area of the gap channel, the valve 16 held by the center cap channel allows air to flow forward (outflow to the external space SP). The resistance is much larger than the channel resistance of the center cap channel.
Therefore, the air in the internal space SP1 flows out to the front external space SP through the center cap flow path while deforming the flap 15b of the valve member 15 so as to open to the front side. That is, it flows out to the external space SP on the front side of the speaker 54 through the opening 4e, the valve restricting member 14, and the valve member 15 (see the black triangular head arrow).
As the vibration continues, the air flow shown in FIGS. 10 and 11 is performed alternately and continuously.

As described above, in the speaker 54, the positions of the intake holes and the exhaust holes are respectively on the side surface side and the front side of the frame 1, and the positions are sufficiently separated from each other.
Therefore, hot air does not flow into the internal space SP1, and since the flowing outside air is always at room temperature, a good heat dissipation effect can be obtained.
In addition, the direction of the air flow generated with the longitudinal movement of the vibration part SD is determined in a substantially constant direction. That is, the route includes the opening 1c of the frame 1, the opening 7a of the damper holder 7, the damper rear space SP2, the gap Gp, the internal space SP1, and the opening 4e of the center cap 4.
Strictly speaking, in the damper rear space SP2, a reciprocating air flow can be generated as the damper 8 moves back and forth. However, the flow direction in the gap Gp in the region where the temperature is significantly increased is almost completely fixed. Maintained.

  As a result, room temperature air that has flowed in from the outside intermittently is supplied to the gap Gp, and when the gap Gp passes through the gap Gp, the voice coil 6 is deprived of heat and raised in temperature. Since it is discharged outside without returning to Gp, high heat dissipation efficiency is exhibited.

<Example 5>
FIGS. 12A and 12B are a front view and a cross-sectional view for explaining the speaker 55 of the fifth embodiment. In the front view of FIG. 12A, the vibration part SD of the speaker 55 is not shown. FIG. 12B is a cross-sectional view of the speaker 55 including the vibration part SD cut along the cutting line AOB in FIG.

In FIG. 12A, one opening 1c of the frame 1 is formed so as to open within an angle range θa. Four openings 1c are provided in the frame 1 at an angular interval of 90 °.
A through hole 13a1 is formed in the pole piece 13a, and the internal space SP1 and the external space SP communicate with each other.
The damper 8 is formed of a material through which air does not pass or a material through which air passes slightly. Further, the air flow path that substantially communicates the damper rear space SP2 and the external space SP is only the flow path through the opening 1c except for the gap flow path. Therefore, the damper rear space SP2 is a substantially closed space except for these two flow paths.
In the speaker 55, a valve 17 is provided corresponding to each of the plurality of openings 1c. The valve 17 is provided in the damper holder 7, for example.
The valve 17 allows the air flow direction to flow from the external space SP through the opening 1c toward the damper rear space SP2, and vice versa, from the internal space SP1 to the external space SP through the opening 1c. Operates to inhibit air flow.

An example of the structure of the valve 17 is shown in FIG. The valve 17 is attached to the damper holder 7 and has a pair of hook-shaped flaps 17a and 17b.
FIG. 13A is a cross-sectional view illustrating the free state of the valve 17.

In FIG. 13A, the valve 17 abuts at a position where the tip ends of the flaps 17a and 17b are biased inward to close the flow path.
In addition, the flaps 17a and 17b themselves are formed so as not to be deformed outward and to be easily deformed inward.
Therefore, when an air flow (refer to the broken line arrow) going from the inside toward the outside urges the flaps 17a and 17b, the urging acts to strengthen the closure of the flaps 17a and 17b, and further the urging direction. Is a direction in which the flaps 17a and 17b are not easily deformed, so that the valve 17 is kept closed.

  On the other hand, as shown in FIG. 13B, when the air flow from the outside toward the inside (see solid arrows) urges the flaps 17a and 17b, the urging releases the closure of the flaps 17a and 17b. Further, since the urging direction is a direction in which the flaps 17a and 17b are easily deformed, the valve 17 is opened and air flows.

Since the valve 17 having this structure is provided in each opening 1c, when the vibration part SD moves to the front side, the damper rear space SP2 passes through the opening 1c and the valve 17 to the side of the external space SP. Air flows in from. Further, air flows into the internal space SP1 from the external space SP through the normally open through hole 13a1.
Next, when the vibration part SD moves rearward, the internal pressure of the damper rear space SP2 increases. Here, the valve 17 prohibits air outflow from the damper rear space SP2 to the external space SP. The air flows out through the gap path and through the internal space SP1 to the external space SP.
As the vibration continues, the air inflow and outflow are repeated alternately and continuously.

As described above, in the speaker 55, the positions of the intake hole and the exhaust hole are respectively on the side surface side and the rear side of the frame 1, and both positions are sufficiently separated from each other.
Accordingly, hot air does not flow into the internal space SP1, and the outside air that flows in is always outside air at room temperature, so that a good heat dissipation effect can be obtained.
In addition, the direction of the air flow generated with the longitudinal movement of the vibration part SD is determined in a substantially constant direction. That is, the route includes the opening 1c of the frame 1, the valve 17, the damper rear space SP2, the gap Gp, the internal space SP1, and the through hole 13a1.
Strictly speaking, in the internal space SP1, as the diaphragm 3 and the center cap 4 move back and forth, an air flow that reciprocates with the external space SP through the through-hole 13a1 that is always open may occur. The flow direction in the gap Gp at the site where the temperature rises remarkably is determined and maintained almost completely in a constant direction.

As a result, room temperature air that has flowed in from the outside intermittently is supplied to the gap Gp, and when the gap Gp passes through the gap Gp, the voice coil 6 is deprived of heat and raised in temperature. Since it is discharged without returning to Gp, the heat dissipation efficiency is improved.
In the fifth embodiment, in combination with the fourth embodiment, the through hole 13a1 is not formed. Instead, a hole that is always open is provided in the center cap 4, and a valve 17 that regulates the air flow in the opening 1c of the frame 1 is provided. It may be good.

FIG. 14A to FIG. 14E are diagrams schematically showing the configurations of the above-described first to fifth embodiments in a generalized manner.
Specifically, in the speaker 51 of the first embodiment shown in FIG. 14A, the volume of the internal space SP1 is increased or decreased mainly by the diaphragm 3 and the center cap 4 in the vibration part SD. The gap Gp is a narrow passage that has a flow path R1 that communicates with the internal space SP1 and a flow path R2 that communicates with the damper rear space SP2, and is disposed so as to go around the voice coil 6.
The volume of the damper rear space SP <b> 2 increases or decreases due to the vibration of the damper 8. The damper rear space SP2 communicates with the lateral external space SP through the opening 1c.
In this configuration, the internal space SP1 and the external space SP are connected by a flow path R3 via a valve 16 that is a check valve. In the speaker 51, the valve 16 allows only the air flow from the external space SP to the internal space SP1 to pass through.

  In the speaker 52 of the second embodiment shown in FIG. 14B, the flow direction allowed by the valve 16 which is a check valve is opposite to that of the speaker 51 in FIG.

In the speaker 53 of the third embodiment shown in FIG. 14C, the center cap 4 that increases or decreases the volume of the internal space SP1 and the external space SP are connected by a flow path R4 via a valve 16 that is a check valve. Yes. On the other hand, the flow path R3 is not formed.
In the speaker 54 of the fourth embodiment shown in FIG. 14D, the flow direction allowed by the valve 16 which is a check valve is reversed with respect to the speaker 53 of FIG. 14C.

  In the speaker 55 of the fifth embodiment shown in FIG. 14 (e), the damper rear space SP2 and the side space SP are connected by a flow path R5 via a valve 17 that is a check valve. In addition, the internal space SP1 is connected to a flow path R1 that extends toward the gap Gp and a flow path R3 that is always open toward the external space SP.

  As is clear from these schematic diagrams, the speakers 51 to 55 of the first to fifth embodiments have a first space (internal space SP1) that is two spaces whose volumes change due to vibration based on an input audio signal from the outside. The first space (flow path R3 or flow path R4) is connected to the second space (damper rear space SP2) via the gap Gp and directly communicates the first space and the external space. And a second communication path (opening 1c or flow path R5) that directly communicates the second space and the external space, and the flow direction is set to the first communication path or the second communication path. A check valve (valve 16 or valve 17) that restricts the direction is provided.

  Each of the above-described first to fifth embodiments may be modified in various ways without departing from the gist of the present invention.

(Modification 1)
In the first modification, the valves 16 and 17 are detachable. Here, a representative example of the original embodiment will be described as the speaker 52 of the second embodiment with reference to FIG.
FIG. 15 shows the speaker 52 of the second embodiment described with reference to FIG. 6 in which the valve 16 can be replaced.
Specifically, a female screw portion 13e is formed on the bottom surface 13a9 of the recess 13a8 in the pole piece 13a, and the valve restricting member 14 and the valve member 15 are fastened and fixed using the washer 18 and the male screw 19.

According to this structure, the user can easily attach and detach the valves 16 and 17. Therefore, for example, when the speaker product is shipped, the valves 16 and 17 are not attached, and the valves 16 and 17 can be retrofitted according to the usage situation (for example, in a usage application requiring a high volume). is there.
Further, the user can easily replace the valve 16 with a different type.
Examples of different types of the valve 16 include those having different channel cross-sectional areas in the open state and those having different pressure differences in the open state.
The structure in which the valve 16 is detachable is not limited to a screw. For example, it may be detachable using a hook-and-loop fastener. Moreover, you may employ | adopt well-known attachment / detachment structures, such as an uneven | corrugated fitting and a snap fit, providing the nail | claw shape which mutually engages.

(Modification 2)
Modification 2 is an example using the valve 20 that can adjust the threshold value for opening and closing the flow path, and will be described with reference to FIGS. 16 and 17. 16A and 16B are cross-sectional views that can be compared with FIGS. 6 and 7, respectively, and FIG. 17 is a cross-sectional view for explaining the valve 20.
A speaker 52 </ b> A shown in FIG. 16 is obtained by replacing the valve 16 with the valve 20 in the speaker 52 of the second embodiment as a representative example. In the following description, different parts from the speaker 52 will be mainly described.

In the speaker 52A, a stepped recess 13d having a large rear diameter is formed on the rear end face of the pole piece 13a.
A ring-shaped receiving seat 13c is attached to the bottom surface 13d1 of the stepped recess 13d. The receiving seat 13c is formed of a flexible material such as rubber.
A plate 21 is attached to the step 13d2 of the stepped recess 13d.
The plate 21 has a female screw portion 21a formed at the center and a plurality of openings 21b formed around the periphery thereof in the circumferential direction, and is formed of metal or the like.
The male screw portion 22 s of the adjusting screw 22 is screwed into the female screw portion 21 a of the plate 21. A knurling is formed on the peripheral surface of the head 22t of the adjusting screw 22, and the adjusting screw 22 can be easily turned by a user's finger.
A lock nut 23 is screwed between the plate 21 and the head portion 22t of the male screw portion 22s of the adjustment screw 22.
Further, a circular tray-shaped spring seat portion 22 a is attached to the tip end side of the adjusting screw 22.
One end side of the coil spring 24 is fitted to the spring seat portion 22a.
An umbrella-shaped contact portion 25 is fitted to the other end side of the coil spring 24. The contact portion 25 is made of a flexible material such as rubber.
Specific examples of the material of the receiving seat 13c and the contact portion 25 include flexible rubber and elastomer, and silicone rubber excellent in heat resistance and quietness in addition to flexibility.

The above-described valve 20 can adjust the distance Ha from the plate 21 in the natural state to the tip of the contact portion 25 according to the amount of feeding in the screwing of the adjusting screw 22, and locks the adjusted arbitrary position. It can be maintained by tightening the nut 23.
In a state where the valve 20 is attached to the speaker 52A, the coil spring 24 is contracted by a predetermined amount so that the contact portion 25 contacts the receiving seat 13c. That is, the contact portion 25 is pressed against the receiving seat 13c by the urging force of the coil spring 24 in the natural state (state shown in FIG. 16A).

In order to open the valve 20, it is necessary to push back the contact portion 25 with a drag force greater than the biasing force of the coil spring 24. Therefore, the threshold for opening and closing the valve 20 can be adjusted by increasing or decreasing the feed amount of the adjusting screw 22.
That is, in the speaker 52A provided with the valve 20, when the air tries to escape from the internal space SP1 through the valve 20 to the external space SP, the pressure difference between the internal space SP1 and the external space SP is a predetermined value (hereinafter referred to as “the pressure difference”). , Referred to as threshold value Ps) or more, the open state is established, and when it is less, the closed state is established.
Further, air flow from the external space SP to the internal space SP1 when the pressure of the internal space SP1 becomes negative with respect to the pressure of the external space SP is always prohibited because the valve 20 cannot be opened.

In the configuration of the speaker 52A, the flow path connecting the internal space SP1 and the external space SP includes the gap Gp, the gap flow path passing through the opening 7a of the damper holder 7, and the opening 1c of the frame 1, the through hole 13a1, and the valve. And a through-hole flow path through 20.
Here, when the vibration part SD as shown in FIG. 16A is moved forward with respect to the position of the reference state, the volume of the internal space SP1 increases from the volume of the reference state, and the internal space SP1. Is negative with respect to the external space SP, so that air can flow into the internal space SP1 from the external space SP.
The flow path resistance of the gap flow path at this time is because the valve 20 held by the through hole path prohibits the flow of air from the external space SP to flow into the through hole 13a1 even though the flow path cross-sectional area is small. The channel resistance of the through-hole channel is smaller.
Therefore, the air on the side of the speaker 52A in the external space SP flows from the opening 1c of the frame 1 into the damper rear space SP2, and further flows into the internal space SP1 through the gap Gp (see the black triangular head arrow).

When time elapses from the forward movement of the vibration part SD shown in FIG. 16A, the vibration part SD moves rearward with respect to the reference state and enters the state of FIG. 16B.
In the state of moving to the rear side, the volume of the internal space SP1 is smaller than the volume of the standard state, and the pressure of the internal space SP1 becomes positive with respect to the external space SP to move from the internal space SP1 to the external space SP. Air outflow.
The flow path resistance of the gap flow path at this time is greater in the gap flow path than in the through-hole flow path when the pressure difference between the internal space SP1 and the external space SP is less than the opening / closing threshold value Ps of the valve 20. Since the road resistance is small, air flows out from the internal space SP1 to the external space SP through the gap Gp. The pressure difference being less than the threshold value Ps corresponds to the case where the amplitude of the vibration part SD is less than a predetermined value.

On the other hand, when the pressure difference between the internal space SP1 and the external space SP is equal to or greater than the threshold value Ps, the valve 20 held by the through-hole channel allows air to flow backward, that is, to flow out to the external space SP through the through-hole 13a1. Therefore, the channel resistance of the through hole channel is smaller than the channel resistance of the gap channel.
Specifically, when the pressure difference is equal to or greater than the threshold value Ps, the air in the internal space SP can push down the contact portion 25 of the valve 20 toward the rear side against the urging force of the coil spring 24, and the valve 20 Opened.
Thus, while the pressure difference is equal to or greater than the threshold value Ps, the air in the internal space SP flows out through the through-hole flow path, that is, through the through-hole 13a1 and the valve 20 to the external space SP (black triangle head arrow). reference).

As described above, the speaker 52 </ b> A of the second modification can set an arbitrary threshold value Ps by adjusting the opening / closing of the valve 20 by turning the adjusting screw 22.
As a result, the operation of the speaker 52A is such that the valve 20 is always closed even during the forward / backward movement (vibration) of the vibration part SD, and the normal heat radiation mode in which the air flow between the inside and outside is small, and the movement of the vibration part SD to the rear side to some extent In the above case, the valve 20 can be opened to switch between the two modes of the positive heat radiation mode enabling a large amount of air flow between the inside and outside and the gap Gp.
The threshold value Ps corresponds to the magnitude of the amplitude of the vibration part SD (in other words, the strength of the input audio signal), so that, for example, the normal heat dissipation mode is set for normal volume reproduction, and the large volume reproduction having a large amplitude is performed. It is possible to perform the heat dissipation control in which the active heat dissipation mode is shifted to only when the heat transfer is performed and the excessive temperature rise of the magnetic circuit is avoided by the progress of heat storage.

Pressure fluctuations in the internal space SP1 and the damper rear space SP2 of the speaker 52A affect the vibration mode of the vibration part SD. That is, the sound quality is affected.
Therefore, for example, as a speaker system in which the speaker 52A is mounted in a cabinet, sound quality tuning that has been carefully examined with the speaker 52A in the normal heat dissipation mode is performed, and a large volume reproduction that is concerned about excessive temperature rise of the magnetic circuit or the like is possible. The use of the two modes, such as setting the threshold value Ps so as to shift to the active heat dissipation mode to prevent the malfunction of the speaker 52A only when it is performed, is very effective.

  The valves 16, 17, and 20 described in each of the above-described embodiments and modifications are opened and closed because the flaps 15 b, 17 a, and 17 b that contribute to the opening and closing of the air flow and the contact portion 25 are formed of a soft material. As a result, noise such as a hitting sound is not substantially generated. Thereby, a favorable heat dissipation effect can be exhibited without affecting the reproduction sound quality of the speaker.

The flow direction regulating structure (member) including the valve used in each of the above-described embodiments and modifications may be a structure that can arbitrarily adjust the ratio between the flow rate flowing in one direction and the flow rate flowing in the other direction.
For example, the valves 16, 17, and 20 correspond to a case where the flow rate flowing in one direction is substantially zero in a structure in which the flow rate ratio can be adjusted.
Thus, the flow direction regulating member including the valve functions in a broad sense as a flow regulating unit that regulates differently the flow rate in one direction and the flow rate in the other direction or restricts the flow direction in only one direction. do it.

  The above-described embodiments and modifications thereof are not limited to the above-described configurations, and may be further modified examples without departing from the gist of the present invention. Moreover, each Example, each modification, and another modification can be combined suitably.

The above-described valves 16, 17, and 20 are disposed in an air flow path and function as a flow direction regulating structure (member) that limits the flow direction of air in the flow path to only one direction.
Therefore, instead of the valves 16, 17, and 20, a flow direction regulating structure other than a so-called movable valve structure that regulates the flow direction by creating an open state and a closed state of the flow path by mechanical movement or deformation of the members, respectively. (Member) may be applied.
In addition, the flow direction regulating structure (member) including the valve may not completely block the flow in the other direction opposite to the regulated one direction, and prohibits the flow in the allowed direction. If the flow rate in the other direction is different from the flow rate so that the flow rate ratio exceeds 1, the heat radiation effect is exhibited.
Further, the heat dissipation effect generally depends on the flow rate ratio. That is, the heat dissipation effect is expected to increase as the flow rate ratio increases.
As a flow direction regulating structure (member) other than the valve structure, there is a so-called fluidic diode that exhibits a flow resistance that varies depending on the flow direction.

A plurality of flow direction regulating structures (members) may be provided as long as the flow of air in one direction defined in the gap Gp is allowed.
For example, in the speaker 53 of the third embodiment whose schematic structure is shown in FIG. 14C, the flow path R3 including the valve 16 in the speaker 51 of the first embodiment whose schematic structure is shown in FIG. You may provide with flow path R4 with respect to internal space SP1.

In the first embodiment, a circular recess 13a8 is formed on the rear surface of the pole piece 13a to open a through hole 13a1 on the bottom surface 13a9 (see FIG. 1), and the valve 16 is valve-regulated against the bottom surface 13a9. It is good also as a modification which piled up and attached the member 14 as the back side and the valve member 15 as the front side.
Also in the modified example of the first embodiment, the same effect as in the first embodiment can be obtained.
In the second embodiment, the valve 16 is overlapped on the bottom surface 13a5 (see FIG. 6) of the recess 13a4 formed on the front surface of the pole piece 13a with the valve regulating member 14 on the front side and the valve member 15 on the rear side. It is good also as an attached modification.
Also in the modified example of the second embodiment, the same effect as in the second embodiment can be obtained.

1 frame, 1a flange, 1b rear end, 1c opening 2 edge 3 diaphragm, 3a opening 4 center cap 4a seat, 4b through hole, 4c annular recess, 4d recess 4d1 bottom surface, 4e opening 5 voice coil bobbin 6 Voice coil 7 Damper holder, 7a Opening 8 Damper 9 Fiber covered wire, 10 Connection terminal 11 Magnet 12 Top plate 13 Yoke 13a Pole piece, 13a1 Through hole 13a2, 13a7 Opening, 13a3 Front 13a4, 13a8 Recess, 13a5, 13a9 Bottom 13a6 Inclined portion, 13b Flange portion, 13c Receiving seat 13d Recessed stepped portion, 13d1 Bottom surface, 13d2 Stepped portion 13e Female threaded portion 14 Valve regulating member, 14a Net portion, 14k Outer frame portion 15 Valve member 15a Cut, 15b Flap, 15k Outer frame portion 1 , 17, 20 Valves 17a, 17b Flap 21 plate, 21a female screw part, 21b opening 22 adjustment screw 22a spring seat part, 22s male screw part, 22t head 23 lock nut, 24 coil spring, 25 abutting parts 51 to 55, 52A Speaker CL1 Axis Gp Gap Ha Distance Ps (Pressure Difference) Thresholds R1 to R5 Channel SD Vibration Part SP External Space, SP1 Internal Space, SP2 Damper Rear Space ZK Magnetic Circuit Part

Claims (5)

A diaphragm,
A magnetic circuit;
A voice coil arranged to vibrate integrally with the diaphragm in the gap of the magnetic circuit;
A speaker with
A ventilation path formed including the gap in the middle;
A flow restricting portion that is provided in the ventilation path and restricts the flow rate in one direction of the passing air to be smaller than the flow rate in the other direction;
A frame having one side integrated with the magnetic circuit, an outer peripheral edge of the diaphragm connected to the other side via an edge, and an opening between the one side and the other side ;
Equipped with a,
The magnetic circuit has a through hole that communicates the internal space and the external space of the speaker;
One end side of the ventilation path communicates with the external space through the opening of the frame, and the other end side communicates with the external space through the through hole of the magnetic circuit. Speaker. The flow restriction is a speaker of claim 1, wherein the regulating the flow rate of air flowing through the through hole of the magnetic circuit. The flow restriction is a speaker of claim 1, wherein the regulating the flow rate of air flowing through the opening of the frame. The flow restriction is a speaker according to any one of claims 1 to 3, characterized in that detachably provided. The speaker according to any one of claims 1 to 4 , wherein the flow restricting unit is capable of adjusting a ratio of a flow rate of the air in one direction and a flow rate in the other direction.