JP4624468B2 - Speaker device - Google Patents

Description

  The present invention relates to a speaker device, and more particularly to an improvement for realizing a thin speaker device by shortening the axial dimension of the speaker device.

FIG. 1 shows a configuration of a conventional general electrodynamic speaker device.
The speaker device 1 has a magnetic circuit 3, a frame 5 to which the magnetic circuit 3 is attached at the rear, and a cone-like shape in which a roll-like edge 7 on the outer periphery is fixed to a diaphragm support 5 a at the front of the frame 5. The diaphragm 9 and a voice coil 12 wound around a cylindrical voice coil bobbin 11 are provided.

The magnetic circuit 3 includes a yoke 15 having a structure in which a cylindrical center pole 15b protrudes from the center of a disk-shaped plate 15a, a ring-shaped magnet 16 that is loosely fitted on the outer periphery of the center pole 15b, and a plate 15a. A ring-shaped top plate 17 is provided so as to be loosely fitted to the front end side of the center pole 15b so as to sandwich the magnet 16 therebetween.
A gap between the inner periphery of the top plate 17 and the center pole 15b is a magnetic gap 19 in which the voice coil 12 is disposed.

The diaphragm 9 has an opening 9a through which the voice coil bobbin 11 is inserted. The edge 7 joined to the outer peripheral edge of the diaphragm 9 includes a ring-shaped gasket 21 in which a mounting flange portion 7a provided on the outer periphery of the edge 7 is attached to the diaphragm support portion 5a and the diaphragm support portion 5a. And is fixed to the diaphragm support portion 5a. The inner peripheral portion 9b of the diaphragm 9 forming the opening 9a is fixed to the outer periphery of the voice coil bobbin 11 inserted through the opening 9a by adhesion or the like.
In addition, a dust cap 23 is attached to the center of the diaphragm 9. The dust cap 23 covers the front of the voice coil bobbin 11 and prevents entry of dust or the like into the magnetic gap 19.

The cylindrical voice coil bobbin 11 is elastically supported by the frame 5 via a damper 25 so as to be freely fitted on the outer periphery of the center pole 15b so as to be movable in the axial direction and to be restricted from moving in the axial direction.
Usually, as the damper 25, a concentric bellows structure with respect to the voice coil bobbin 11 is widely used (see, for example, Patent Document 1 and Patent Document 2).
The damper 25 has an outer peripheral edge fixed to the damper support part 5b of the frame 5, an inner peripheral part fixed to the outer periphery of the voice coil bobbin 11, and restricts the radial displacement of the voice coil bobbin 11, and the diaphragm When driving 9, the vibration energy is absorbed by the deformation of the bellows, and the vibration plate 9 is damped.

  Normally, the frame 5 has a structure in which an opening 5c is appropriately provided between the diaphragm support portion 5a and the damper support portion 5b. The opening 5c functions as a vent for releasing back pressure when the diaphragm 9 is driven, and at the same time contributes to weight reduction of the frame.

  When the sound signal is input to the voice coil 12 via the input terminal and the tinsel wire (not shown), the speaker device 1 described above vibrates the diaphragm 9 by the reciprocating vibration of the voice coil bobbin 11 and thereby reproduces the sound. do.

JP-A 63-155900 JP-A-11-262085

By the way, recently, an in-vehicle audio system that incorporates a speaker device for reproducing heavy bass such as a woofer or a subwoofer is increasing.
In the case of such a vehicle-mounted speaker device, it is important to make the speaker device thin so that the speaker device can be incorporated even in parts where the depth dimension is limited, such as a vehicle door or a ceiling panel. Yes.

  However, in the conventional speaker device 1 in which the voice coil bobbin 11 is elastically supported by the damper 25 as described above, a space for disposing the damper 25 must be secured between the diaphragm 9 and the magnetic circuit 3. In order to secure the installation space of 25, it is difficult to reduce the axial dimension of the speaker device, which has been a bottleneck for making the speaker device thinner.

Further, since the damper 25 has a stiffness greater than that of the normal edge 7, mechanical fatigue due to long-term use occurs earlier than the edge 7, and there is a possibility that a decrease in control performance may cause a failure.
Further, due to deformation of the bellows during vibration propagation between adjacent bellows on the damper 25, unusual vibrations and rubbing sounds are generated, which adversely affect the vibrations of the voice coil 12 and the diaphragm 9, thereby reducing the sound quality. There was also a possibility of becoming cloudy.

  The problems to be solved by the present invention include the problem that it is difficult to shorten the axial dimension of the speaker device in order to secure the installation space of the damper that occurs in the above-described prior art, and the mechanical fatigue of the damper in long-term use. An example is a problem in which a decrease in support performance causes a failure, and a problem in which a unique vibration or rubbing sound is generated due to deformation of the damper.

  According to a first aspect of the present invention, there is provided a speaker device comprising: a first diaphragm and a second diaphragm arranged coaxially along a driving direction; and a substantially frustoconical frame extending in a sound radiation direction. The outer peripheral part of the diaphragm and the second diaphragm are fixed to the diaphragm support part on the frame via edges provided respectively, and the inner peripheral part of the second diaphragm is a voice Fixed to the coil bobbin, the inner periphery of the first diaphragm is fixed to the second diaphragm, and the space surrounded by the first diaphragm, the second diaphragm and the frame is hermetically sealed The vibration system is supported via the voice coil bobbin by the spring property of the gas in the space.

It is a longitudinal cross-sectional view which shows the structure of the conventional speaker apparatus. It is a longitudinal cross-sectional view of 1st Embodiment of the speaker apparatus based on this invention. FIG. 3 is an explanatory diagram of an operation at the time of driving the speaker device illustrated in FIG. 2. It is a principal part longitudinal cross-sectional view of 2nd Embodiment of the speaker apparatus based on this invention.

  Hereinafter, embodiments of a speaker device according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 2 is a longitudinal sectional view of the first embodiment of the speaker device according to the present invention, and FIG. 3 is a diagram for explaining the operation of the speaker device shown in FIG.
As shown in FIG. 2, the speaker device 30 of the first embodiment includes a magnetic circuit 33, a frame 35 to which the magnetic circuit 33 is attached at the rear, and a first coaxially arranged in the driving direction. The diaphragm 41 and the second diaphragm 42, and a voice coil 46 wound around a cylindrical voice coil bobbin 45. Reference numeral 37 denotes a center line of the speaker device 30. As shown in the figure, the frame 35 has a substantially frustoconical shape spreading in the sound radiation direction, and has a larger diameter in the sound radiation direction.

  The magnetic circuit 33 includes a yoke 51 having a structure in which a cylindrical center pole 51b protrudes from the center of a disk-shaped plate 51a, a ring-shaped magnet 53 loosely fitted on the outer periphery of the center pole 51b, and a plate 51a. A ring-shaped top plate 55 is provided that is loosely fitted to the tip of the center pole 51b so as to sandwich the magnet 53 therebetween. A gap between the inner periphery of the top plate 55 and the center pole 51b is a magnetic gap 57 in which the voice coil 46 is disposed.

The frame 35 has a shallow bowl shape, and the magnetic circuit 33 is attached to the inner surface of the bottom plate portion 35a with the plate 51a of the yoke 51 mounted thereon.
The frame 35 is equipped with a vibration plate support portion 35c of the first vibration plate 41 and a vibration plate support portion 35d of the second vibration plate 42 at positions separated along the driving direction.
The peripheral wall 35b between the two diaphragm support portions 35c and 35d is a sealed wall in which no opening is provided. However, there is no passage between the diaphragm support portion 35d and the bottom plate portion 35a to release the back pressure of the diaphragm. Openings 35f as pores are appropriately provided.
The back surface of the diaphragm support portion 35c of the frame 35 functions as a flange surface that is tightly fixed to the baffle 71 of the speaker cabinet.

The first diaphragm 41 and the second diaphragm 42 are cone-shaped diaphragms, and the edges 61 and 62 that are outer peripheral portions thereof are fixed to the diaphragm support portions 35 c and 35 d on the frame 35. The inner peripheral portions 41 b and 42 b are joined and fixed to the voice coil bobbin 45.
The edges 61 and 62 are preferably made of a material having a high internal loss in order to attenuate the vibration transmitted from the cone paper as the diaphragm main body. Therefore, for example, a member made of a material different from cone paper (a material having higher internal loss than cone paper) may be joined to form the edges 61 and 62.

As for the 1st diaphragm 41 arrange | positioned at the front side of a speaker apparatus, the diameter of the opening of a center part is set larger than the diameter of the opening of the 2nd diaphragm 42 arrange | positioned at the front side of a speaker apparatus. The edge 61 is provided with a bulging portion 61a that bulges outside the sealed space 67 between the diaphragms (front side of the speaker device).
Further, the second diaphragm 42 disposed on the back of the first diaphragm 41 has a central opening whose diameter is set to be substantially equal to the outer diameter of the voice coil bobbin 45, and the edge 62 has a gap between the diaphragms. A bulging portion 62a that swells outside the closed space 67 (on the back side of the speaker device) is provided.
In addition, the direction of the unevenness | corrugation of the bulging part 61a and the bulging part 62a is not limited to the direction of FIG.

The edges 61 and 62 of the first diaphragm 41 and the second diaphragm 42 are fixed to the two diaphragm support portions 35c and 35d of the frame 35, respectively.
Note that the edge 61 of the first diaphragm 41 is fixed to the diaphragm support 35c with the mounting flange 61b connected to the outer periphery thereof held between the gasket 65 and the diaphragm support 35c. Yes.

In addition, the inner peripheral portion 41 b of the first diaphragm 41 is joined to the second diaphragm 42 in a state of being overlaid on the second diaphragm 42 located behind the first diaphragm 41.
In addition, a dust cap 23 is attached to the central portion of the first diaphragm 41. The dust cap 23 covers the front of the voice coil bobbin 45 and prevents entry of dust or the like into the magnetic gap 57.

  Then, the inner peripheral portion 42b of the second diaphragm 42 is bonded and fixed to the outer periphery of the voice coil bobbin 45 with an appropriate adhesive, thereby the inner peripheral portions 41b of the first diaphragm 41 and the second diaphragm 42, 42b is joined and the structure fixed to the voice coil bobbin 45 is obtained.

  The cylindrical voice coil bobbin 45 is freely fitted in the outer periphery of the center pole 51b so as to be movable in the axial direction, and is positioned in the radial direction and the axial direction by the second diaphragm 42 joined to the outer periphery. ing.

In the present embodiment, the space 67 between the diaphragms surrounded by the first diaphragm 41 and the second diaphragm 42 and the frame 35 is sealed.
When the first diaphragm 41 and the second diaphragm 42 are driven by the axial displacement of the voice coil bobbin 45, a gas such as air sealed in a sealed space 67 between the diaphragms as shown in FIG. Is compressed by the displacement of the first diaphragm 41 and the second diaphragm 42 and the displacement of the edges 61a and 62a, and the spring property as an air spring is exhibited.
In the present embodiment, the effective area difference S when the effective area of the first diaphragm is S1 and the effective area of the second diaphragm is S2 is S = S1-S2, and between the diaphragms Assuming that the volume V of the air in the sealed space 67 is, the stiffness, which is a constant representing the spring property of the air spring, can be made proportional to S / V.
In the present embodiment, the frame 35 has a substantially frustoconical shape that spreads in the sound radiation direction, so that a difference S between the effective areas of the first diaphragm 41 and the second diaphragm 42 is easily generated, and S1 ( It becomes easy to configure such that the effective area of the first diaphragm >> S2 (effective area of the second diaphragm). Therefore, the stiffness of the air spring can be increased.
That is, in this embodiment, the voice coil bobbin 45 is supported in a controllable manner by the spring property as an air spring provided in the sealed space 67 between the diaphragms.

In the speaker device 30 of the present embodiment described above, the spring property as an air spring in the sealed space 67 between the diaphragms absorbs the vibration energy of the voice coil bobbin 45 and the diaphragms 41 and 42, and these voice coil bobbins 45. In addition, since the diaphragm is controlled, there is no need to provide a control damper as provided in a conventional speaker device.
In other words, in the speaker device 30 of the present embodiment, the first diaphragm 41 and the second diaphragm 42 themselves also serve as dampers for controlling the vibration of the diaphragm and the voice coil bobbin 45, so that the rear of the diaphragm In addition, it is not necessary to equip a damper for elastically supporting the voice coil bobbin 45, and the axial dimension of the speaker device is shortened by omitting the damper and its installation space, so that the speaker device 30 required for an in-vehicle audio system or the like is thin Can be realized.

  Moreover, the second diaphragm 42 that is coaxially provided behind the first diaphragm 41 in order to realize a sealed space 67 between the sealed diaphragms is made of the same material as that of the first diaphragm 41. As compared with a conventional bellows structure damper, mechanical fatigue is less likely to occur, so that a reduction in vibration damping performance due to mechanical fatigue of the component parts can be prevented, and a longer lifetime of the speaker device can be realized.

  Further, unlike the conventional bellows structure damper in which the deformation moves between adjacent bellows (undulations) during vibration propagation, the first diaphragm 41 and the second diaphragm 42 have a large deformation locally. Therefore, high-quality sound reproduction without turbidity can be realized without generation of singular vibration and rubbing sound that cause turbidity of sound quality.

  In the speaker device 30 of the present embodiment, the edges 61 and 62 of the diaphragms 41 and 42 are resistant to deformation due to back pressure with the aid of the gas pressure in the sealed space 67 between the sealed diaphragms. Further, since the second diaphragm 42 and its edge 62 bear the back pressure, the burden of the back pressure applied to the first diaphragm 41 that performs sound reproduction is reduced, and the reproduction sound quality can be improved.

(Second Embodiment)
FIG. 4 is a longitudinal sectional view of an essential part of a second embodiment of the speaker device according to the present invention.
The speaker device 40 according to the second embodiment is similar to the speaker device 30 according to the first embodiment shown in FIGS. 2 and 3, as shown in FIG. 4. The second diaphragm 42 is connected by a rib 81 (connecting member). The ribs 81 are appropriately provided at a plurality of locations at predetermined intervals.

By the connection by the ribs 81, the rigidity of the first diaphragm 41 and the second diaphragm 42 forming the sealed space 67 between the diaphragms is strengthened, and the propagation speed of acoustic vibration is improved, and the like. High-quality sound playback is possible.
Further, by connecting the first diaphragm 41 and the second diaphragm 42 by the ribs 81, the vibration energy is quickly dispersed over a wide range of the diaphragms 41 and 42, thereby suppressing local distortion of the diaphragm. The burden on the vibration energy to be absorbed can be reduced, and the fatigue resistance of the diaphragms 41 and 42 can be improved.

  In the first and second embodiments described above, the inner diameter of the second diaphragm 42 located on the back side is smaller than the first diaphragm 41 located on the front side, so that the second The inner peripheral part of the diaphragm 42 was joined to the voice coil bobbin 45. However, conversely, the inner diameter of the first diaphragm 41 is made smaller than the second diaphragm 42, and the inner peripheral portion of the second diaphragm 42 is joined and integrated with the intermediate portion of the first diaphragm 41. The inner periphery of the first diaphragm 41 can be joined to the voice coil bobbin 45.

  Further, it may be considered that the inner diameters of the first diaphragm 41 and the second diaphragm 42 are aligned with the outer diameter of the voice coil bobbin 45 and the inner peripheral portions of the respective diaphragms are directly joined to the voice coil bobbin 45. It is done.

  As described above in detail, the speaker devices 30 and 40 according to the first and second embodiments include the first diaphragm 41 and the second diaphragm 42 disposed coaxially along the driving direction. The outer peripheral portions 61 and 62 of the first diaphragm 41 and the second diaphragm 42 are fixed to the diaphragm support portions 35c and 35d on the frame 35, and the first diaphragm 41 and the second diaphragm 41 The inner peripheral portions 41a and 42a of the diaphragm 42 are joined and fixed to the voice coil bobbin 45, and the space 67 surrounded by the first diaphragm 41 and the second diaphragm 42 and the frame 35 is sealed and sealed. The voice coil bobbin 45 is supported by the spring property of the gas in the space 67.

Thereby, since the spring characteristic as an air spring of the sealed space 67 between the diaphragms 41 and 42 controls the vibration of the voice coil bobbin 45 and the diaphragms 41 and 42, it is not necessary to provide a dedicated damper for the control.
Therefore, the axial dimension of the speaker device 30 can be shortened by omitting the damper and its installation space, and in particular, the speaker device that is required in the in-vehicle audio system can be made thinner.

  Further, since the second diaphragm 42 can be made of the same material as the first diaphragm 41, the second diaphragm 42 is lighter in mass and less likely to cause mechanical fatigue as compared with a conventional bellows structure damper. Prevents deterioration of vibration control performance due to mechanical fatigue of parts, can extend the service life of the speaker device, and does not cause significant deformation locally. It is possible to realize high-quality sound reproduction without generating turbidity.

23 Dust cap 30, 40 Speaker device 33 Magnetic circuit 35 Frame 35a Bottom plate part 35b Peripheral wall 35c, 35d Diaphragm support part 37 Central axis 41 First diaphragm 41b Inner circumference part (of the first diaphragm) 42 Second Diaphragm 42b Inner peripheral portion (of second diaphragm) 45 Voice coil bobbin 46 Voice coil 57 Magnetic gap 51 Yoke 53 Magnet 55 Top plate 61, 62 Edge 65 Gasket 67 Sealed space between diaphragms 81 Rib

Claims (4)

A first diaphragm and a second diaphragm disposed coaxially along the drive direction;
A substantially frustoconical frame extending in the sound radiation direction,
The outer peripheries of the first diaphragm and the second diaphragm are fixed to the diaphragm support on the frame via edges provided respectively,
The inner periphery of the second diaphragm is fixed to a voice coil bobbin,
The inner periphery of the first diaphragm is fixed to the second diaphragm,
A space surrounded by the first diaphragm and the second diaphragm and the frame is sealed;
A loudspeaker apparatus, wherein a vibration system is supported via the voice coil bobbin by a gas spring property in the space.   2. The speaker device according to claim 1, wherein the first diaphragm and the second diaphragm are respectively supported by the diaphragm support portion at a position separated along a driving direction.   The speaker device according to claim 1 or 2, wherein the first diaphragm and the second diaphragm are connected by a connecting member. The speaker device according to any one of claims 1 to 3, wherein the first diaphragm and the second diaphragm have a diaphragm main body and the outer peripheral portion made of different members.

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