JPH0614388A - Diaphragm for loudspeaker - Google Patents

Abstract

PURPOSE:To obtain the diaphragm which can be manufactured easily, and also, is light in weight and does not increase a mechanical impedance of a vibrating system, and also, has moderate rigidity and vibration energy absorbing capacity and has an action for suppressing abnormal vibration of the diaphragm, etc., by constituting the diaphragm of a base material obtained by mixing and making a casein fiber and pulp. CONSTITUTION:The diaphragm is manufactured by a base material obtained by mixing and making a casein fiber and pulp. Also, it is desirable that the casein fiber is a fiber obtained by drawing out a solution obtained by dissolving a milk casein in 10% alkali into a nitric acid coagulation bath from a spinneret and coagulating it like a thread, and thereafter, allowing it to pass through a formalin bath, while applying tension, and executing its unsolubilization treatment, and thereafter, executing hot air drying. A full line and a dotted line in the figure show the case when a loudspeaker using an embodiment diaphragm is specified, and the case when a conventional example diaphragm consisting of only pulse is used, respectively, and a one-point chain line shown other conventional example using a carbon fiber laminated material, and in a band of >=2kHz, as for a frequency characteristic of the embodiment, a peak and a dip decrease, and a smooth characteristic is shown.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm of a speaker used in various audio equipment, and more particularly to a diaphragm made of an improved fibrous material.

[0002]

2. Description of the Related Art As is well known, a diaphragm of a speaker is required to have high elasticity and high internal loss, and a metal, a synthetic resin, a fibrous material impregnated with a resin as a shaping material, and a laminate of these materials. However, paper-based diaphragms made from pulp are still widely used because they have low density, high internal loss and are bulky, and their shapes are easy to control. Various attempts have been made. In this attempt, the strength of the diaphragm is usually improved by impregnating pulp with various resins or mixing it with high strength fibers.

[0003]

In any of the conventional hard diaphragms having the above structure, it is difficult to maintain a good balance between the rigidity and the mechanical internal loss, and the reproduced sound is unnatural. There was a problem to be solved that there are many speakers that have become.

Therefore, the present invention solves the drawbacks of the conventional example, is easy to manufacture, is lightweight, does not increase the mechanical impedance of the vibration system, and has appropriate rigidity and vibration energy absorption capability. An object of the present invention is to provide a speaker having excellent quality by obtaining a diaphragm having an action of suppressing abnormal vibration of the diaphragm and the like.

[0005]

A speaker diaphragm according to the present invention for achieving the above object is a speaker diaphragm comprising a base material obtained by mixing casein fiber and pulp. Casein fiber contains 10% milk casein
A solution obtained by dissolving it in alkali is drawn out from the spinneret into a nitric acid coagulation bath to coagulate it into filaments, then passed through a formalin bath while applying tension to insolubilize it and then dry with hot air. Is a diaphragm for a speaker.

[0006]

In the vibrating plate of the present application, the mixed casein fiber has elasticity as compared with the vegetable fiber because the physical properties of the casein fiber are bent, and the vibrating plate of the present invention and the conventional fibrous material As shown in Table 1 by comparing the physical property values of the base material with the diaphragm having the material impregnated with the synthetic resin, the rigidity is not much different from the conventional example due to the presence of pulp, that is, plant fiber,
On the other hand, tan δ, which is a measure of the absorption of vibration energy, is larger than that of the conventional example.

[0007] As a result, it has rigidity and a proper vibration energy absorption capacity in balance with the effect of suppressing significant divisional vibration and abnormal vibration of the diaphragm, and the frequency characteristics in the middle and high frequencies are improved. . FIG. 1 shows frequency characteristics of a speaker using the diaphragm of the present embodiment and a speaker using two types of conventional diaphragms.

[0008]

[Table 1]

[0009]

Example About 5% acetic acid was added to milk and stirred, and the precipitated casein was dehydrated and dried to obtain milk casein powder.
This milk casein powder was dissolved in 10% alkali and the resulting solution was sent to a spinneret with many 3 mil holes, and the filament drawn from the spinneret was 10 m / m.
After passing through a nitric acid coagulation bath at about 0 ° C to coagulate at a speed of in, it is passed through a formalin bath under tension to be insolubilized, and further dried with hot air at 80 ° C to remove unnecessary solvent. Etc. were evaporated to obtain casein fiber.

80% of unbleached kraft pulp and 20% of Manila hemp pulp were beaten with a beater until a beating degree of 25 ° SR, and then dyed and sized.

On the other hand, the casein fiber was crushed with a homogenizer into 0.2 to 2.0 micron and mixed by 5% by weight with respect to the above pulp to adjust the total fiber concentration to 0.05%. Then, it was made into a diaphragm shape, heated and dried to obtain a cone-shaped diaphragm for a speaker with a nominal diameter of 16 cm and a weight of 2 g.

For comparison, as a conventional example, a diaphragm made of only the above pulp, and as another conventional example, a diaphragm made of a carbon fiber laminated material, which is considered to have the highest rigidity at present, is prepared to assemble loudspeakers. The properties were measured. FIG. 1 shows the respective frequency characteristics. The solid line represents the characteristics of the speaker using the example diaphragm, the dotted line represents the characteristics of the speaker using the conventional example diaphragm made of only pulp, and the dashed line represents the speaker of the other conventional example diaphragm using the carbon fiber laminated material. When comparing the two, the frequency characteristics of the example in the band of 2 KHz or more are peaks, dips are reduced, and the characteristics are smooth, and it is predicted from the physical property values shown in Table 1 in the base material that the elasticity is large. It shows the characteristics.

The speaker diaphragm according to the present invention and the method for manufacturing the speaker diaphragm have been described above in detail based on the examples considered to be typical. However, the embodiment of the diaphragm according to the present invention is limited to the structures of the above-mentioned examples. However, the present invention can be appropriately modified and implemented as long as it has the constituent features described in the above-mentioned claims, exhibits the action of the present invention, and has the effects described below.

[0014]

[Effect] The speaker diaphragm according to the present invention has the following effects. (1) Since the diaphragm of the present application simply mixes casein fibers with conventional pulp, it is extremely easy to manufacture as in the conventional case. (2) The molecular chain of casein fiber as a raw material is bent,
Since the elasticity is large, the physical properties of the base material are relatively high as shown in Table 1, and the tan δ is also larger than that of the conventional example. Therefore, the abnormal divided vibration mode of the diaphragm is suppressed and changed, as shown in FIG. As shown in, the frequency characteristic in the high frequency band is improved. Therefore, it is possible to provide a speaker having excellent quality for obtaining a good reproduced sound.

[Brief description of drawings]

FIG. 1 is a frequency characteristic diagram of each speaker using the diaphragm of the example of the present application and a conventional example.

Claims (2)

[Claims] 1. A speaker diaphragm comprising a base material obtained by mixing casein fibers and pulp. 2. The casein fiber comprises 1 part of milk casein.
The solution obtained by dissolving it in 0% alkali is drawn out from the spinneret into a nitric acid coagulation bath to coagulate it into a filamentous form, which is then passed through a formalin bath under tension to insolubilize it and then dried with hot air. The speaker diaphragm according to claim 1, wherein the diaphragm is a casein fiber.