JPS623990Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention relates to the improvement of supporting members such as dampers or edges of speakers. To explain the supporting members of speakers with reference to Fig. 1, 1 is a magnetic circuit, 2 is a voice coil 3 wound around. The voice coil 3 is a coil bobbin, and the voice coil 3 is arranged in the magnetic gap of the magnetic circuit 1.

4 is a damper having a wavy cross section for suppressing the coil bobbin 2 from vibrating only in the axial direction and moving in a direction perpendicular to this; 5 is a diaphragm coupled to the upper end of the coil bobbin 2; 6 is a damper This is an edge portion connected between the outermost peripheral edge of the diaphragm 5 and the opening edge of the frame 7, and has a wavy or semicircular cross section. The edge 6 has the function of supporting the center of the diaphragm and terminating the vibration energy propagated from the diaphragm 5.

Such support members are usually made by impregnating a woven or knitted fabric made of natural or synthetic resin with an excipient, and then heating and pressurizing the excipient in a mold with a wavy or semicircular cross section to harden the excipient. The wavy cross-sectional shape or semicircular cross-sectional shape is maintained, and a viscoelastic material with a large internal loss is applied to the edge 6 in particular to terminate the vibration propagating from the diaphragm, thereby creating a steep peak or dip in the frequency characteristic. suppress the occurrence of

In such a structure, a phenol resin dissolved in a methanol solution has conventionally been frequently used for the following reasons.

That is, the voice coil 3 generates Joule heat due to the sound current flowing through it, and its temperature rises to about 200°C.

This heat is then transferred from the coil bobbin 2 to the damper 4.

For example, when a light metal such as aluminum is used for the coil bobbin 2, the temperature at the root of the damper 4 and the coil bobbin 2 reaches 130°C to 160°C.

Therefore, the excipient material must be heat resistant enough not to deform at this temperature, and as a result, thermosetting resins such as phenolic resins, which have a higher deformation temperature, are used rather than thermoplastic resins, which have a lower deformation temperature. be.

Regarding the Edge 6, if the diaphragm 6 is made of natural fiber or synthetic resin, almost no heat from the voice coil is transferred, but if a metal diaphragm is used, consideration must be given to heat as with the damper 4. becomes.

Next, the molding process will be described in more detail. After impregnating the base fabric with a phenolic resin in a methanol solvent, it is heated and dried at 100°C to 150°C to bring the phenolic resin into a semi-hardened state.

The phenolic resin is completely cured by press molding for about 50 minutes in a mold heated to about 140°C or for 1 to 3 minutes in a mold heated to 200°C to 230°C.

In such a molding process, various problems occur due to variations in the degree of curing of the phenolic resin.

That is, the time from heating and drying to press forming may vary (because a certain amount of press material is retained during the process).

Therefore, the degree of curing differs depending on the time for which it is left to stand, so if press molding is performed under certain conditions, the curing state will vary, and when incorporated into a speaker, f _O , and f _H will vary.

In addition, thermosetting resins require a considerable amount of time to completely cure, and in mass production, it is preferable to perform press molding in a single hour, so press molding must be carried out at high temperatures. It cannot be completely cured.

Therefore, even after being incorporated into a speaker, curing is gradually accelerated, resulting in the drawback that the stiffness changes over time, and the quality at the time of design cannot be maintained.

Furthermore, as mentioned above, the need for press-forming at high temperatures limits the materials for the fabric (particularly fabrics made of thermoplastic fibers can hardly be used), so there is also the drawback that the degree of freedom in design is extremely limited.

Therefore, this invention is a support member using aromatic polysulfone resin, which is a thermoplastic resin with a high heat deformation temperature, as a excipient, and will be described in detail below.

Polyethersulfone resin, which is a type of aromatic polysulfone resin, is shown by the structural formula below. The heat distortion temperature of the resin is approximately 200℃.

Another type of polysulfone resin is a resin shown by the structural formula below, and its heat distortion temperature is approximately 170℃. It is.

Next, we will discuss the molding process using polyether sulfon resin. Polyether sulfon resin is dissolved in a mixed solution of equal amounts of methylene chloride and chloroform as a solvent 12, and this is impregnated into fabric 11 (see Figure 2). a) After at least volatilizing the solvent, press molding is carried out for several seconds in molds 13, 13 heated to 170°C (Fig. 2b).

At that time, the polyether sulfone resin softens under high pressure in the mold at high temperature, and the fabric is formed into the shape of the mold by press pressure, and as it cools, the polyether sulfon resin hardens. The fabric is shaped into the shape of the support member.

The support member with this structure uses thermoplastic resin, which has stable properties after molding and molding, instead of thermosetting resin as the excipient material. Disadvantage,
Defects during the manufacturing process can be completely eliminated.

The aromatic polysulfone resin has an extremely high deformation temperature compared to conventional thermoplastic resins (for example, polyether sulfone resin has a deformation temperature of approximately 200°C, polysulfone resin has a deformation temperature of approximately 170°C, and conventional thermoplastic polycarbonate resins have a (approximately 130°C, polyethylene terephthalate approximately 90°C), so it can sufficiently withstand heating due to Joule heat generated in the voice coil, and the resin also resists changes in mechanical properties due to temperature changes. (Temperature dependence) is extremely small compared to conventional synthetic resins, so it is extremely excellent in practical use, with little deterioration in properties even after long-term continuous use.

Furthermore, it is possible to apply a loss material to the damper or edge obtained by this invention, or to apply heat molding after application to give an internal loss to the diaphragm and block air permeability. may be selected depending on the design purpose.

[Brief explanation of drawings]

Figure 1 is a sectional view of the speaker, Figure 2 a and b
FIG. 2 is a cross-sectional view showing the process of forming the support member of this invention.

Claims (1)

[Scope of utility model registration request] A speaker support member made by impregnating a woven or knitted fabric made of natural or synthetic fibers with an aromatic polysulfone resin and then heat molding the impregnated fabric.