JPS5822382Y2 - speaker unit - Google Patents

Description

[Detailed description of the invention] The present invention relates to the improvement of a speaker unit, and in particular, selects sound absorbing material to be loaded on the inner surface of the diaphragm and near the magnetic circuit, thereby improving sound quality and input resistance characteristics. This is what was planned.

For example, a mood type speaker unit is known in which glass wool is loaded as a sound absorbing material between the diaphragm and the pole piece.

However, the problems found in such conventional sound absorbing materials are (a)
Since the single fibers have high rigidity, they lack flexibility as a sound absorbing material, causing uneven contact with the diaphragm and easily generating abnormal noise.

(b) Since it is a poor conductor of heat, it has the properties of an insulating material, leading to an increase in the temperature of the magnetic circuit section and deterioration of the input resistance characteristics.

(C) When made into a mat, the intertwining of single fibers is poor;
Due to this, the fallen fibers are scattered, but there is a problem that they tend to stick to fingers, etc., and therefore workability is inevitably reduced.

In conclusion, glass wool and similar materials can be seen as materials that are rather unsuitable as sound absorbing materials.

The present invention has been developed in view of these points, and has achieved the purpose of the invention as stated at the beginning by conducting many experiments with this type of sound absorbing material and by making new innovations in the loading structure for the speaker unit. It's in the middle of the day.

A specific example of the present invention will be explained below with reference to the drawings.
The key point is that a fibrous activated carbon mat (mainly refers to an irregularly packed material, hereinafter simply referred to as activated carbon mat in the text) is used as a sound absorbing material, and this activated carbon mat is rationally loaded into the speaker unit. It lies in the structure.

FIG. 1 is a longitudinal sectional view showing the main parts of an example of a dome-shaped speaker unit according to the present invention.

In the figure, 1A is the entire speaker unit, 2 is the front frame, and 3 is a convex spherical shell-shaped diaphragm placed in the opening of the speaker unit (a non-metallic diaphragm made of a thin plate pressed part made of aluminum alloy, titanium alloy, beryllium alloy, etc., or a soft dome). 4 is a coil bobbin, 5 is a damper, 6 is a voice coil, 7 is a plate, 8 is a magnet,
Reference numeral 9 indicates a yoke, 10 indicates a pole piece, and 11 indicates a protective mesh that also serves as a radiator, and the basic structure of such a dome-shaped speaker unit itself is widely known.

In the present invention, as an example, the inner surface of the diaphragm 3, which is a member of the speaker unit 1A shown in the drawing, and the pole piece 10 are used.
The above-mentioned activated carbon mat 12 is placed as a sound absorbing material between the end face of the
By loading the dome with an appropriate density, it avoids the occurrence of abnormal noise without damaging the original characteristics of the dome shape, and suppresses the temperature rise of the magnetic circuit section including the voice coil, and increases its input resistance characteristics. The loading density of the activated carbon mat 12 is determined experimentally.

Therefore, the activated carbon mat 12 as a sound-absorbing material will be described in detail mainly to outline the physical characteristics of the fibrous activated carbon mat.For convenience, the activated carbon mat 12 is shown as a flat rectangular block in FIG. The mat does not mean its form, but simply refers to a dense body of fibers, and the single fibers 12' of this activated carbon mat 12 are fibrous activated carbon made from acrylic resin and have good thermal conductivity. It is made of very flexible fibers with a diameter of 6 to 8μ, and when made into a mat (or felt), the intertwining of the single fibers is far superior to that of glass wool, and there is almost no fiber shedding, and the It is also extremely easy to handle.

Therefore, in the case of this example, such activated carbon mat 1 is used as the sound absorbing material.
2 is loaded in the manner described above, the following actions and effects can be achieved.

That is, (a) the single fiber has sufficient flexibility;
The contact with the diaphragm becomes uniform, and abnormal noise can be prevented from occurring.

(b) The thermal diffusivity is high due to the good thermal conductivity of the entire mat, and therefore the temperature rise in the magnetic circuit portion is also small, so that the input resistance characteristics thereof can be improved.

(C) Workability in the assembly process can be improved because there is almost no fiber falling off from the loading mat.

If these are compared with the drawbacks observed in the conventional sound absorbing materials listed above, the effects of the present invention will become clear.

FIG. 3 is a longitudinal cross-sectional view of the main parts showing another embodiment of the present invention. Corresponding parts to those in FIG. be.

In this embodiment, a through hole 13 of an appropriate diameter is formed in the center of the yoke 9 and the pole piece 10 integrated therewith, and a drive unit cover 14 made of a non-magnetic material is provided to cover the back side of the yoke 9. , the inside of the chamber 15 and the inner surface of the diaphragm 3 are communicated with each other, and the activated carbon mat 12 is loaded in all the spaces extending from the inner surface of the diaphragm 3 to the chamber 15, including the through holes 13. There is.

Note that the reference numeral 1B is the entire speaker unit.

That is, by adopting such a structure, the resonance of the diaphragm 3 increases,
The purpose is to avoid abnormal vibrations, increases in non-linear strain, etc., and to obtain the effect of the perforations 13, and to obtain the unique functions and effects brought about by the activated carbon mat 12 in the same way as in the previous example.
According to this example, since the activated carbon mat 12 is also loaded into the through hole 13 and the chamber 15, the temperature rise in the magnetic circuit section is further suppressed, and therefore the input resistance characteristics are particularly improved, which need no explanation. Will.

Furthermore, FIG. 4 is a longitudinal cross-sectional view of a horn-type speaker unit to which the present invention is applied. A flange 16' is attached to the front of the yoke 9 (in the unit of this example, the yoke 9 is arranged in front of the magnet 8, and the pole piece 10 is hollow, and an equalizer 17 is installed inside it. The diaphragm 3 has a concave spherical shell shape, but this structure itself is well known).

In the case of this embodiment, a cover 14 similar to the example shown in FIG. 3 is attached around the plate 7 to form a chamber 15,
The activated carbon mat 12 is loaded into the chamber 15, and the functions and effects of this example are substantially the same as those of the previous examples.

Therefore, the present invention adopts a fibrous activated carbon mat as a result of many experiments regarding the sound absorbing material of the speaker unit, and if it is possible to improve the sound quality, improve the input resistance characteristics, and streamline the workability as mentioned above, The benefits obtained from this are enormous.

Note that the present invention can also be applied to speaker systems other than the dome type and horn type.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an example of a dome-shaped speaker unit according to the present invention, Fig. 2 is a perspective view illustrating a fibrous activated carbon mat, and Figs. It is a longitudinal cross-sectional view showing an example. In the figure, IA, IB and 1C are speaker units, 3
1 is a diaphragm, 7 is a plate, 8 is a magnet, 9 is a yoke, 10 is a pole piece, 12 is an activated carbon mat, 12' is a single fiber thereof, 13 is a through hole, 14 is a cover, and 15 is a chamber.

Claims (1)

[Scope of utility model registration request] A sound absorbing material made of a fibrous activated carbon mat is loaded on the inner surface of the diaphragm and in the vicinity of the magnetic circuit section that drives the diaphragm,
A speaker unit configured primarily to prevent the generation of abnormal noise from the speaker and improve its human resistance characteristics.