JPH03795Y2 - - 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 21, a center pole 22, a front plate 23, and a back plate 24, as shown in FIG.
The edge 27 supports the diaphragm so that the voice coil 26 fixed to the outer periphery of the diaphragm 25 is positioned in the magnetic gap formed by the center pole 22 and the front plate 23 of the magnetic circuit. The diaphragm 25 is driven through an electric current to emit sound waves.

The diaphragm 25 is usually made of a lightweight and highly rigid material such as duralumin in order to make the divided vibration frequency as high 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 phases of the diaphragm are opposite to each other outside and inside this vibration node, a dip occurs in the frequency characteristics at the anti-resonance frequency ( _R ).
Furthermore, a peak occurred at the subsequent high resonance frequency ( _H ), deteriorating the frequency characteristics and transient characteristics, and impairing 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.

[Effect of idea]

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 dome-shaped speaker according to the present invention includes a dome-shaped diaphragm 1, a voice coil bobbin 2 coupled to the lower outer circumference of the dome-shaped diaphragm 1, and a voice coil bobbin 2 wound around the voice coil bobbin 2. It has a vibration system consisting of a rotated voice coil 3 and an edge 4 bonded near the joint between the diaphragm 1 and the voice coil bobbin 2, and the voice coil bobbin 2 is made of cloth or nonwoven fabric as a base material, and The upper end of the voice coil 3 and the diaphragm 1 of the base material
At least one flexible part 5 is formed between the lower surface and the corresponding part by impregnating and molding a soft excipient material or by omitting the excipient material, and the flexible part 5 The rest of the voice coil bobbin 2 has a structure in which the rigidity in the circumferential direction of the voice coil bobbin 2 is made non-uniform by impregnating it with a hard excipient material and forming a solid structure.

[Effect]

In the vibration system having the above configuration, the flexible portion of the voice coil bobbin has low rigidity and does not have a sufficient reinforcing effect on the diaphragm. Furthermore, since the propagation of the driving force to the diaphragm becomes partially uneven, the significant anti-resonance and resonance in _R and _H as in the conventional example are dispersed, and the resulting frequency characteristics are The dips and peaks of the sound disappear, resulting in a flat frequency characteristic, and at the same time, the significant resonance disappears, resulting in better transient characteristics, resulting in a marked improvement in the reproduced sound quality.

〔Example〕

The configuration of the vibration system of the dome-shaped speaker of the present invention will be explained in detail with reference to FIG.

1 is a diaphragm made of a lightweight, highly rigid material such as metal or reinforced synthetic resin; 2 is a voice coil bobbin, which is made of cloth or non-woven fabric with two types of excipients, hard and soft, depending on the predetermined parts; It is made of a composite material that is separately impregnated and integrally molded, and a soft excipient is used in a part above the voice coil 3 winding part, or
Alternatively, the rigidity of the upper part of the voice coil bobbin 2 can be reduced by omitting the shaping material, providing at least one flexible part 5 with reduced rigidity, and using a hard shaping material for the remaining parts. The structure changes over time.

The voice coil 3 is wound around the voice coil bobbin 2, and the edge 4 is bonded near the boundary between the voice coil bobbin 2 and the diaphragm 1.

According to the results of experiments, the size of the above-mentioned soft part 5 is that the width W is about 3 to 50% of the total circumference of the diaphragm, and the vertical width d ranges from a simple slit to the entire area excluding the voice coil winding part. Within the range of 1 or more (4 locations in the illustrated example) or about 5 locations, good results are obtained.

As another embodiment, the diaphragm 1 and the voice coil bobbin 2 may be integrally molded from the same material. However, in this case, the portion of the diaphragm 1 is impregnated with a hard excipient material to provide a diaphragm with a solid structure.

Compared to using the diaphragm 1 as a separate member, it has the advantage of reducing the number of manufacturing steps and lowering the manufacturing cost.

Regarding the material of the composite material forming the diaphragm 1 and the voice coil bobbin 2, the material is not limited, and the material of the cloth or nonwoven fabric may be natural fiber, synthetic fiber, or a mixture of both.

As hard excipients, epoxy resins, urethane resins, acrylic resins, phenolic resins, etc. can be used, and as soft excipients, viscoelastic substances such as rubber, silicone resins, UV loss agents, etc. can be used. can.

〔effect〕

FIG. 3 shows a comparison of the frequency characteristics of the dome-shaped speaker according to the present invention and a conventional example.

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

In the characteristics of conventional speakers, there is a dip due to anti-resonance at approximately 20KHz and a peak due to high-frequency resonance around 30KHz, whereas in the dome-shaped speaker of the present invention, significant peaks and dips disappear in the above frequency band. This shows that the structure of the vibration system according to the present invention is effective in dispersing and eliminating significant resonance and anti-resonance.

In addition, since the diaphragm is mainly made of a 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 drawings]

FIG. 1 is a partially cutaway perspective view of the vibration system of the dome-shaped speaker of the present invention, FIG. 2 is a sectional view of a conventional dome-shaped speaker, and FIG. 3 is a frequency characteristic diagram. 1 is a diaphragm, 2 is a voice coil bobbin, 3 is a voice coil, 4 is an edge, and 5 is a flexible portion.

Claims (1)

[Claims for Utility Model Registration] 1. A dome-shaped hard diaphragm 1, a voice coil bobbin 2 coupled to the lower outer periphery of the dome-shaped diaphragm 1, and a voice coil 3 wound around the voice coil bobbin 2. and the diaphragm 1
In the dome-shaped speaker, the voice coil bobbin 2 has a base material made of cloth or nonwoven fabric, and the voice coil bobbin 2 has an upper end portion of the voice coil 3 of the base material. At least one flexible part 5 is formed between the lower surface of the diaphragm 1 and the corresponding part by impregnating and molding a soft excipient material, or by omitting the excipient material, and at least one part other than the flexible part 5 is formed. A dome-shaped speaker characterized by its parts being made of a solid material impregnated with a hard excipient material and molded. 2. Claims for registration of a utility model characterized in that the voice coil bobbin 2 and the diaphragm 1 are made of the same material, and the diaphragm 1 is integrally formed by impregnating only a hard excipient material. The dome-shaped speaker described in item 1.