JPH0129913Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to an improvement of the vibration system of a dome-shaped speaker in the field of electroacoustic equipment.

[Conventional technology]

A dome-shaped speaker generally has a magnet 31, a center pole 32, a front plate 33, and a back plate 34, as shown in FIG.
The edge 37 supports the diaphragm so that the voice coil 36 fixed to the outer periphery of the diaphragm 35 is positioned in the magnetic gap formed by the center pole 32 and the front plate 33 of the magnetic circuit. The diaphragm 35 is driven through an electric current to emit sound waves.

The diaphragm 35 is usually made of a lightweight and highly rigid material such as duralumin in order to increase the divided vibration frequency as much as possible and improve the frequency characteristics.

Another configuration of the dome-shaped speaker is that the diaphragm is made of a soft material with extremely high internal loss.
There are so-called soft dome speakers.

[Problems to be solved]

In the conventional example described above, the diaphragm using a high-rigidity material has low mechanical internal loss as a material, so at frequencies higher than the piston vibration range,
The vibration energy transmitted from the periphery of the diaphragm and the vibration energy reflected at the center of the diaphragm interfere with each other, causing vibration nodes near the outer periphery of the diaphragm due to so-called anti-resonance. Since the vibration phase of the diaphragm outside and inside this vibration node is opposite to each other, the frequency of the anti-resonance is
A dip occurs in the frequency characteristics in _FR .
Furthermore, a peak was generated at the subsequent high-frequency resonance frequency _FH , resulting in deterioration of the frequency characteristics and transient characteristics, which impaired the sense of hearing.

In addition, in the latter type of soft dome speaker, the internal loss of the diaphragm is extremely large, so resonance and anti-resonance are unlikely to occur, but the diaphragm has a large mass and it is difficult to transmit vibration energy, so the conversion efficiency as a speaker is extremely low. It was hot.

[Purpose of invention]

The present invention eliminates the drawbacks of the conventional example described above and uses an improved vibration system to prevent anti-resonance from occurring.
The purpose is to obtain a dome-shaped speaker with good frequency characteristics and efficiency.

[Means for solving problems]

In order to achieve the above object, the vibration system of the dome-shaped speaker according to the present invention includes a voice coil bobbin, a voice coil wound around the voice coil bobbin, and a dome-shaped hard material diaphragm having a smaller diameter than the voice coil. , and an edge bonded to the upper end of the voice coil bobbin, the edge is made of a composite material in which a thin film of hard material and a sheet of soft material are laminated, and an extension part having the same curvature as the diaphragm is integrally formed on the inner periphery. The thin film of hard material is partially removed from one or more locations of the extended portion to provide a flexible portion made of only a sheet of soft material, and the diaphragm is adhered to the inside and periphery of the extended portion.

[Effect]

In the vibration system having the above configuration, the rigidity of the edge extension that supports the diaphragm is nonuniform over the entire circumference due to the flexible part provided in the edge extension, and as a result, the stiffness of the edge extension that supports the diaphragm is not uniform over the entire circumference. Since the stiffness of the outer periphery of the diaphragm differs along the circumferential direction, significant anti-resonance and resonance in F _R and F _H as in the conventional example are dispersed, and the frequency characteristics caused by these are dispersed. Dips and peaks disappear, resulting in flat frequency characteristics, and at the same time, significant resonance disappears, resulting in good transient characteristics, resulting in a marked improvement in reproduced sound quality.
Furthermore, since the voice coil bobbin is not directly connected to the diaphragm, the stiffness of the extension acts as a high-cut filter, and has the effect of cutting off unnecessary high frequencies.

〔Example〕

The vibration system of the dome-shaped speaker according to the present invention will be explained in detail with reference to FIGS. 1 and 2.

The voice coil bobbin 2 is finished in a cylindrical shape using the same material as the conventional one, and the voice coil 3 is wound around the lower end.

The diaphragm 1 is made of metal, paper impregnated with a hard excipient,
It is made of a lightweight, highly rigid material such as cloth or synthetic resin reinforced with a highly rigid filler, and its diameter is smaller than that of the voice coil bopin 2.

The edge 4 is laminated with a thin film 5 of a hard material such as a synthetic resin reinforced with a highly rigid filler such as metal, ceramic, or graphite, and a sheet 6 of a soft material such as a soft synthetic resin, rubber, cloth, cloth impregnated with a viscoelastic material, etc. An extension part 41 is integrally formed from the inner peripheral part with the same curvature as the diaphragm 1, and the extension part 4
1, the above-mentioned diaphragm 1 is adhered, and the above-mentioned hard material thin film 5 is partially removed from one or more places (four places in the illustrated example) on the front edge 4 extension part 41 outside the diaphragm. The flexible portion 42 is formed of only the soft material sheet 6, and the rigidity of the extension portion 41 is made non-uniform locally.

A voice coil bobbin 2 with a voice coil 3 wound around its lower end is adhered to the lower surface of the edge 4, and the driving force from the voice coil 3 is transmitted through the voice coil bobbin 2 and is applied to the diaphragm 1 via the extension 41 of the edge 4. transmitted to the outer periphery.

The flexible portion 4 provided in this edge 4 extension portion 41
The size of No. 2 is a size that falls within the range of the extension outside the diaphragm, and the radial dimension d ranges from a minimum gap of a mere cut to about 50% of the radius of the inner circumference of the edge. Width W is 3~3 of the entire inner circumference of edge 4
Approximately 50%, and the number of locations provided is one or more (four in the illustrated example) and approximately six provides better results according to experimental results.

Furthermore, the hard material thin film 5 on the edge 4 is partially coated.
Alternatively, it is also possible to adjust the edge compliance by removing the entire layer.

〔effect〕

FIG. 4 shows the frequency characteristics of the dome-shaped speaker according to the present invention in comparison with a conventional example.

The solid line shows the characteristics of the dome-shaped speaker of the present invention, and the dotted line shows the characteristics of the conventional example.

In the conventional example, there are large peaks and dips at approximately 20KHz to 30KHz that are thought to be caused by resonance and anti-resonance, but in the present invention, these peaks and dips are dispersed and disappear, and the frequency characteristics are flat. Therefore, it is clear that the configuration of the vibration system according to the present invention is extremely effective in improving the frequency characteristics of a dome-shaped speaker.

In addition, since the diaphragm is mainly made of hard material and is lighter than a soft dome diaphragm, there is no drop in efficiency, resulting in a dome-shaped speaker with excellent frequency characteristics and transient characteristics not seen in conventional speakers. It is something that can be done.

[Brief explanation of the drawing]

1 and 2 are a front view and a half-sectional view of the vibration system of the dome-shaped speaker of the present invention, FIG. 3 is a sectional view of a general dome-shaped speaker, and FIG. 4 is a frequency characteristic diagram. 1 is a diaphragm, 2 is a voice coil bobbin, 3 is a voice coil, 4 is an edge, 41 is an extension part, and 42 is a flexible part.

Claims (1)

[Scope of utility model registration request] Dome-shaped diaphragm 1, voice coil bobbin 2,
and a dome-shaped speaker having a vibration system consisting of a voice coil 3 wound around the voice coil bobbin 2, and an edge 4 bonded to the upper end of the voice coil bobbin 2. The sheet 6 is made of a laminated composite material, and an extension 41 having approximately the same curvature as the diaphragm 1 is formed on the inner circumference of the edge 4, and the hard material thin film 5 is partially applied to the extension 41 at one or more locations. A dome-shaped vibration system having a vibration system configured such that a flexible portion 42 made of only a soft material sheet 6 is removed, and a diaphragm 1 having a smaller diameter than the voice coil 3 is attached to the inside and periphery of the extension portion 41. speaker.