JP2006333241A - Speaker device with reinforced diaphragm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker device with reinforced diaphragms, wherein an enclosed space is formed between two diaphragms and the diaphragms are reinforced in the enclosed space with a reinforcing member without decreasing the volume of the enclosed space. <P>SOLUTION: The speaker device includes the diaphragms 41 and a drive cone 42 arranged along a drive direction. Outer circumferential parts 61, 62 of the diaphragms 41 and the drive cone 42 are fixed to diaphragm supports 35c, 35d on a frame 35. The enclosed space 67 is formed by a space surrounded by the diaphragms 41, the drive cone 42, and the frame 35. The diaphragms 41 and the drive cone 42 are connected by non-annular connecting plate piece 70 in the enclosed space 67, and a vibration system is supported via a voice coil bobbin 45 by the elasticity of a gas in the enclosed space 67. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a diaphragm-reinforced speaker device.

  As a general example of an electrodynamic speaker device, a magnetic circuit, a frame holding the magnetic circuit at the rear, a cone-shaped diaphragm in which a roll-shaped edge of the outer periphery of the diaphragm is fixed to the front of the frame, And a voice coil wound around a cylindrical voice coil bobbin that is movable in the axial direction. The voice coil bobbin is elastically supported by the frame via a damper for restricting movement in the axial direction. As the damper, a bellows structure that is concentric with the voice coil bobbin is usually employed (Patent Document 1 and Patent Document 2).

  However, in the type in which the vibration system is supported by this damper, the speaker device is elongated in the axial direction, and the vibration system has a large stiffness, and the support performance is likely to be lowered due to mechanical fatigue. Therefore, a damperless speaker device has been developed in which a sealed space is formed between a pair of diaphragms in place of the damper, and the vibration system is supported using the spring property of the gas in the sealed space.

1A and 1B show the damperless speaker device, wherein FIG. 1A is a longitudinal sectional view and FIG. 1B is a plan view of the speaker device as viewed from the front.
First, the magnetic circuit 33 including the magnet 53, the frame 35 carrying the magnetic circuit 33, the cylindrical voice coil bobbin 45 disposed so as to be axially movable with respect to the magnetic circuit 33, and the magnetic circuit 33 are opposed to each other. Thus, the voice coil 46 wound around the voice coil bobbin 45 and the voice coil bobbin 45 are concentrically spaced apart from each other in the axial direction and the outer periphery is fixed to the frame 35, and the inner periphery is joined to each other and fixed to the voice coil bobbin 45. The diaphragm 41 and the drive cone 42 that transmits the drive of the voice coil 46 to the diaphragm 41 are sealed, and the space surrounded by the diaphragm 41, the drive cone 42 and the frame 35 is sealed. The diaphragm 41 and the drive cone 42 are connected and reinforced by a connecting member 75. Reference numeral 23 denotes a dust cap on the front surface of the speaker device.
The rigidity of the diaphragm 41 and the drive cone 42 is reinforced by the reinforcement by the connecting member 75, and the propagation speed of the acoustic vibration is improved.
JP-A 63-155900 JP-A-11-262085 Japanese Utility Model Publication No. 7-5199

The gas in the sealed space between the diaphragms exhibits a function as a spring property, but the volume of the sealed space affects the spring property constant, that is, the stiffness (see Patent Document 3 in which the sealed space is movable). Specifically, the volume of the enclosed space of the vibration plates is reduced, next the stiffness is large, correspondingly, the low frequency reproduction ability of the reproduced sound becomes higher minimum resonance frequency f ₀ decreases.

Further, the connecting member 75 having the structure shown in FIGS. 1A and 1B has a closed annular shape in which a plate material is formed in an annular shape, and the inside of the annular connecting member 75 (shaded portion in FIG. 1). Is not in communication with the sealed space 67, the volume of the sealed space 67 is reduced by the volume of the connecting member 75.
On the other hand, when the number of the connecting members 75 is increased, the rigidity of the diaphragm 41 and the drive cone 42 is increased, but the volume of the sealed space 67 is greatly decreased, which is an obstacle to lowering the lowest resonance frequency.

  As a problem to be solved by the present invention, in a speaker device of a type in which a vibration system is supported by a gas spring in a sealed space between the diaphragms, a rib-like shape for connecting the diaphragms to increase the rigidity of the diaphragms. There is a problem that the volume of the sealed space is reduced by the connecting member, and it is costly to connect the inside of the connecting member and the sealed space by drilling a vent hole by machining or the like in the side portion of the connecting member that is in the closed annular shape. As an example, there is a problem that it is not practical and a problem that it is difficult to achieve both sufficient reinforcement of the diaphragm and volume of the sealed space with the conventional annular connecting member.

  A diaphragm-reinforced speaker device according to claim 1 includes a diaphragm arranged along a driving direction and a drive cone that transmits driving of a voice coil to the diaphragm, and an outer peripheral portion of the diaphragm and the drive cone. Is fixed to the diaphragm support portion on the frame, and the space surrounded by the diaphragm, the drive cone and the frame is a sealed space, and the diaphragm and the drive cone are in the sealed space. It is connected by a non-annular connecting plate piece, and the vibration system is supported via the voice coil bobbin by the gas spring property in the sealed space.

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

2A and 2B show an embodiment of a diaphragm-reinforced speaker device according to the present invention. FIG. 2A is a longitudinal sectional view of the speaker device, and FIG. 2B is a plan view showing the front surface of the speaker device. .
As shown in FIG. 2, the speaker device 30 of this embodiment includes a magnetic circuit 33, a frame 35 on which the magnetic circuit 33 is attached to the rear inner wall, a diaphragm 41 and a voice arranged coaxially in the driving direction. In a sealed space 67 surrounded by the drive cone 42 that transmits the drive of the coil 46 to the diaphragm 41, the voice coil 46 wound around the cylindrical voice coil bobbin 45, the diaphragm 41, the drive cone 42, and the frame 35. This is a configuration including a plurality of semicircular connecting plate pieces 70 for connecting the diaphragm 41 and the drive cone 42.

  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 vibration plate 41 and a vibration plate support portion 35d of the drive cone 42 at positions separated along the driving direction.

The diaphragm 41 and the drive cone 42 are cone-shaped diaphragms, and the edges 61 and 62 that are outer peripheral portions thereof are fixed to the diaphragm supporting portions 35c and 35d on the frame 35, and the inner peripheral portion 41a thereof. , 42a 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, it is preferable to join the members made of a material different from the cone paper (a material having higher internal loss than the cone paper) to form the edges 61 and 62.

The diaphragm 41 disposed on the front side of the speaker device has a central opening diameter set larger than the opening diameter of the drive cone 42, and the edge 61 has an outside of the sealed space 67 between the diaphragms ( A bulging portion 61a that swells is provided on the front side of the speaker device.
Further, the drive cone 42 disposed on the back of the diaphragm 41 has an opening diameter at the center set substantially equal to the outer diameter of the voice coil bobbin 45, and the edge 62 has an outside of the sealed space 67 between the diaphragms. A bulging portion 62a that swells is provided on the back side of the speaker device.

The outer peripheral portions 41b and 42b of the respective edges 61 and 62 of the vibration plate 41 and the drive cone 42 are fixed to the two vibration plate support portions 35c and 35d of the frame 35, respectively.
The edge 61 of the vibration plate 41 is fixed to the vibration plate support portion 35c with a mounting flange portion 61b connected to the outer periphery thereof sandwiched between the gasket 65 and the vibration plate support portion 35c.

Further, the inner peripheral portion 41a of the diaphragm 41 is joined to the drive cone 42 in a state of being superimposed on the drive cone 42 located behind the diaphragm 41.
A dust cap 23 is attached to the center of the 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.

  The inner peripheral portion 42 a of the drive cone 42 is bonded and fixed to the outer periphery of the voice coil bobbin 45 with an appropriate adhesive so that the diaphragm 41 and the inner peripheral portions 41 a and 42 a of the drive cone 42 are joined and fixed to the voice coil bobbin 45. I got the structure.

  The cylindrical voice coil bobbin 45 is freely fitted on 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 a drive cone 42 joined to the outer periphery.

In the sealed space 67, a pedestal 71 formed by bending a plate material into an L shape is fixed to the curved drive cone 42 (only the reinforcing connecting portion). The front surface of the pedestal 71 (the front surface side of the speaker device) is a flat surface that is substantially perpendicular to the center line of the speaker device 30 and is formed substantially parallel to the inner surface of the diaphragm 41 that faces this portion.
A connecting plate piece 70 that is semicircular in a front view (see FIG. 1B) extends from the inner surface of the diaphragm 41 substantially perpendicularly to the inner surface at a portion facing the pedestal 71, and an end portion 70a thereof is a pedestal. It is fixed to 71. A plurality of connecting plate pieces 70 are provided around the center of the diaphragm as appropriate at predetermined intervals, preferably at equal intervals. The connecting plate piece 70 may be formed of the same member as the diaphragm 41.

The semicircular connecting plate piece 70 connects and reinforces the vibration plate 41 and the drive cone 42 via the pedestal 71, thereby enhancing the rigidity of the vibration plate 41 and the drive cone 42 forming the sealed space 67. Thus, the propagation speed of acoustic vibration is improved, and high-quality sound reproduction is possible.
Further, by the connection by the connecting plate piece 70, the vibration energy is quickly distributed over a wide range of the vibration plate 41 and the drive cone 42, the distortion of the local vibration plate is suppressed, and the burden on the vibration energy to be absorbed is reduced. The fatigue resistance of the diaphragm 41 and the drive cone 42 is improved.

  Here, the smaller the difference in vibration area between the air spring diaphragm 41 and the drive cone 42, and the larger the volume of the sealed space 67, the softer. In the present embodiment, if the difference between the effective area of the diaphragm 41 and the effective area of the drive cone 42 is ΔS, and the volume of the sealed space 67 is V, the spring constant, ie, the spring constant representing the spring property of the air spring, Stiffness is proportional to ΔS / V.

Figure 4 is a graph showing the relationship between the volume V and the lowest resonance frequency f ₀ of the closed space 67, Example SP1 (an example of a diaphragm reinforcing speaker device of the present embodiment shown in FIG. 2) and the conventional example SP2 The measured value of (an example of the conventional damperless speaker device shown in FIG. 1) is shown.
Since the diaphragm-reinforced speaker device of the present embodiment has a larger volume V of the sealed space 67 than the conventional damperless speaker device, the stiffness is reduced, and therefore the lowest resonance frequency f ₀ is shown in the graph of FIG. Thus, it is possible to reduce the low frequency reproduction ability of the reproduced sound.

In the above-described embodiment, the connecting plate piece 70 is formed in a semicircular shape when viewed from the front, that is, a cylindrical half. However, the connecting plate piece 70 is not necessarily limited to this shape. For example, the cross section in FIG. Any shape such as a crescent shape as shown in FIG. 3, a mountain shape as shown in FIG. 3B, an L shape as shown in FIG. 3C, or a U shape as shown in FIG. 3D can be adopted. In either case, since one side portion is opened and the concave portion of the connecting plate piece 70 communicates directly with the sealed space 67, the volume reduction of the sealed space 67 due to the connecting plate piece 70 is suppressed, and the sealed space 67 is maximized. it can, spring constant of the air spring in the sealed space 67 can be realized to reduce the minimum resonance frequency f ₀ becomes smaller. Further, since these non-annular connecting plate pieces 70 have an arc shape or a bent shape in cross section, the non-annular connecting plate pieces 70 have a higher reinforcing performance than a flat reinforcing plate and ensure a good rigidity of the diaphragm. .

  When the diaphragm 41 and the drive cone 42 are driven by the axial displacement of the voice coil bobbin 45, a gas such as air enclosed in the sealed space 67 between the diaphragms 41, 42 is displaced by the diaphragm 41 and the drive cone 42. The spring 61 is compressed by the displacement of the edges 61 and 62 to exert the spring property as an air spring, and the voice coil bobbin 45 is controlled by the springs of the edges 61 and 62 themselves and the air spring regulated by the volume of the sealed space 67. Supported as possible.

  In the speaker device 30 of the present embodiment, the diaphragm 41 and the drive cone 42 themselves also serve as a damper having a vibration control function, and the spring property as an air spring of the sealed space 67 between the diaphragms is a voice coil bobbin 45. Further, the vibration energy of the diaphragm 41 and the drive cone 42 is absorbed, and the voice coil bobbin 45, the diaphragm 41 and the drive cone 42 are controlled, so that the conventional bellows damper type speaker device is used for control. There is no need to install a damper. By eliminating the damper and its installation space, the axial dimension of the speaker device is reduced, and the speaker device 30 required for an in-vehicle audio system can be thinned.

  Further, the drive cone 42 coaxially provided behind the diaphragm 41 in order to realize the sealed space 67 between the diaphragms may be made of the same material as that of the diaphragm 41. Compared to a damper having a conventional bellows structure, Since mechanical fatigue is unlikely to occur, it is possible to prevent the vibration damping performance from being lowered due to mechanical fatigue of the component parts and to extend the life of the speaker device.

  In addition, unlike the conventional bellows structure damper in which the deformation moves between adjacent bellows during vibration propagation, the diaphragm 41 and the drive cone 42 are not greatly deformed locally, causing the sound quality to become muddy. There is no generation of singular vibration and rubbing noise, and high-quality sound reproduction without turbidity can be realized.

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

  As described above in detail, the diaphragm-reinforced speaker device 30 according to the embodiment of the present invention includes the diaphragm 41 and the drive cone 42 arranged along the driving direction, and includes the diaphragm 41 and the drive cone. The outer peripheral portions 41b and 42b of the frame 42 are fixed to the diaphragm support portions 35c and 35d on the frame 35, and a space surrounded by the diaphragm 41, the drive cone 42 and the frame 35 is a sealed space 67. The vibration plate 41 and the drive cone 42 are connected to each other by a non-circular connection plate piece 70 in 67, and the vibration system is supported through the voice coil bobbin 45 by the spring property of the gas in the sealed space 67.

As described above, since the reinforcing member for securing the rigidity of the vibration plate 41 and the drive cone 42 is configured by the non-circular curved plate piece or the bent plate piece, the volume of the sealed space can be reduced like a closed annular reinforcing member. without that leads to decrease the volume of the closed space 67 can be suppressed to a minimum from the expense, it can be suppressed as much as possible an increase in the minimum resonance frequency f _0. Since the spring characteristic as an air spring of the sealed space 67 between the diaphragm 41 and the drive cone 42 controls the vibration of the voice coil bobbin 45 and the diaphragm 41 and the drive cone 42, it is necessary to provide a dedicated damper for control. Disappears. Furthermore, the axial dimension of the speaker device 30 can be shortened by eliminating the damper and its installation space, and in particular, the speaker device that is required for an in-vehicle audio system can be thinned.

  Further, since the drive cone 42 can use the same material as that of the diaphragm 41, the mass is lighter and mechanical fatigue is less likely to occur compared to a conventional bellows structure damper. This can prevent the deterioration of the vibration damping performance and extend the service life of the speaker device. In addition, since there is no significant local deformation, there is no occurrence of singular vibration or rubbing noise that causes the sound quality to become turbid. High-quality sound reproduction without noise can be realized.

  The drive cone 42 is not limited to the shape of the above-described embodiment, and may have any shape as long as it transmits the drive of the voice coil 46 to the diaphragm 41.

It is the partial longitudinal cross-sectional view and front view which show the structure of the conventional speaker apparatus. It is the partial longitudinal cross-sectional view and front view of the diaphragm reinforcement type speaker apparatus which concern on embodiment of this invention. It is the cross-sectional view which illustrated the various forms of the non-annular connection board piece applied to this invention. Is a graph showing the relationship between the volume V and the lowest resonance frequency f ₀ of the enclosed space.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 Speaker apparatus 33 Magnetic circuit 35 Frame 35c, 35d Diaphragm support part 41 Diaphragm 42 Drive cone 45 Voice coil bobbin 57 Magnetic gap 61, 62 Edge 67 Sealed space between diaphragms 70 Non-annular connection plate piece 71 Base

Claims (4)

A diaphragm disposed along the drive direction and a drive cone that transmits the drive of the voice coil to the diaphragm,
The diaphragm and the outer periphery of the drive cone are fixed to the diaphragm support on the frame,
The space surrounded by the diaphragm and the drive cone and the frame is a sealed space,
In the sealed space, the diaphragm and the drive cone are connected by a non-annular connecting plate piece,
A diaphragm-reinforced speaker device, wherein a vibration system is supported via the voice coil bobbin by a gas spring property in the sealed space.   The diaphragm-reinforced speaker device according to claim 1, wherein an inner peripheral portion of the drive cone is fixed to the voice coil bobbin.   3. The diaphragm reinforcing die according to claim 1, wherein a plurality of the non-annular connecting plate pieces are provided at equal intervals and concentrically with respect to a center of the diaphragm and the drive cone. Speaker device.   4. The diaphragm reinforcement according to claim 1, wherein the non-annular connecting plate piece is provided on a straight flat base attached to the curved surface of the diaphragm or the drive cone. 5. Type speaker device.

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