JPS587997A - speaker dust cap - Google Patents

Abstract

PURPOSE:To suppress the resonance of a dust cap and improve the adhesive property, by forming the dust cap for a speaker with a chlorinated olefin resin or a complex consisting partially of this resin. CONSTITUTION:A dust cap 11 for a conical speaker is formed with materials, which is formed with chlorinated polyethylene into a shape like a film, by vacuum or pressure molding. In this cap, the adheisve property is improved by the activated radical of chlorine to obtain a sufficient adhesive strength. Further, a very high adhesive strength is obtained in case that a metallic foil is laminated on chlorinated polyethylene and a thermoplastic resin or reinforced thermoplatic resin having a high Young's modulus is laminated. Chlorinated polyethylene is mixed in polyethylene to increase the adhesive strength. The similar effect is obtained in case of the use of chlorinated polypropylene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dust camp for cone-shaped speakers and the like.

As shown in Figure 1, the cone type speaker has plate 1.
a magnetic circuit 4 including a magnetic gap 3 formed by a center pole 2 and a center pole 2; a voice coil 5 disposed within the magnetic gap 3;
a damper 7 that elastically supports the coil bobbin 6 in the center, a cone paper 8 fixed to the upper end of the coil bobbin 6, an edge 10 that connects the outer edge of the cone paper 8 and a frame 9, and the edge 10 The outer edge of the paper cone is extended and molded integrally, or it is molded from separate parts and then glued together. and a dust cap 11 fixed to the upper edge of the coil bobbin 6 or near the attachment portion of the cone paper 8 to the coil bobbin 6.

As is well known, the dust cap 11 connects the coil bobbin 6 and the center pole 2 from the upper end opening of the coil bobbin 6.
The purpose is to prevent dust in the air from entering the gap between the

Meanwhile, since the dust gap 11 is coupled to the coil bobbin 6 or the cone paper 8, it vibrates according to the vibration of the coil bobbin 6 and radiates sound waves forward.

If this sound wave is in phase with the sound wave radiated from the paper cone 8, there will be no adverse effect; a sharp peak or dip will occur in the high frequency characteristics of the car, causing a significant deterioration of hearing sensation.

However, at present, no consideration has been given to suppressing the resonance of the dust cap 11, and at most, some internal loss is imparted by attaching or painting a viscoelastic material or the like. be.

Generally, a large internal loss and a large Young's modulus are contradictory properties in terms of material properties, and it is extremely difficult to satisfy both.

From this point of view, among synthetic resin materials, polyolefin synthetic resin materials are currently attracting attention as materials that are close to the above objectives.

For example, polyethylene, which is one of the polyolefin synthetic resins mentioned above, has a small density (ρ<10), but E/ρ(
E: Young's modulus, ρ: density) is large, so the second moment of area per unit weight (E b”/12, h: thickness)
Due to the large size, the shape rigidity is large and the internal loss (t
an δ) of 005 to 01, which is a very large characteristic, and is more preferable as a material for the dust cap.

However, as is well known, since the polyolefin resin has a non-polar crystal structure, it has defects in which adhesiveness is extremely poor.

Therefore, when using the polyolefin resin for the dust cap, the adhesive strength with the diaphragm or coil bobbin becomes a problem, and various proposals have been made to solve this problem.

For example, there are methods of activating the surface of the resin by corona discharge, gas flame, or chemical treatment, and surface treatment by sandblasting.

Although these treatments improve adhesion to some extent, it is not desirable to add such treatment means from a cost standpoint.

Therefore, this invention improves adhesion by forming a dust cap with a chlorinated polyolefin resin, minimizes the associated cost increase, and minimizes the deterioration of the properties of the polyolefin resin. The chlorinated polyethylene will be explained in more detail below.

Chlorinated polyethylene is produced by chlorinating polyethylene in a solution or suspension of carbon tetrachloride, chloroform, trichloroethyl V7, etc. (7) at a temperature below 60°C, or by chlorinating polyethylene powder in an aqueous suspension underarm chlorine gas. obtained by converting

By molding these into a film, a chlorinated polyethylene dust cap material is completed.

A dust cap (dome shape, etc.) is obtained by vacuum or pressure forming this as in the conventional manner.

Dust caps made of such chlorinated polyethylene have improved adhesion due to the active groups created by chlorine, and can provide sufficient adhesive strength between the dust cap and the diaphragm and coil bobbin without any other treatment. .

In addition, there are various advantages when the present invention is applied not only to the chlorinated polyethylene alone but also to a composite dust cap in which the chlorinated polyethylene is used as a part of the structure.

For example, in order to impart rigidity to the chlorinated polyethylene diaphragm, titanium, aluminum, magnesium, aluminum, etc., or alloys and compounds thereof, and boron layers may be added to the surface to further increase the rigidity of the above metals. or thermoplastic resins that are more rigid than chlorinated polyethylene, such as polystyrene, styrene-based copolymers, ABS resins, PVC, polycarbonates, polybutylene terephthalate, or carbon fibers, carbon flakes, and polymers. When providing a dust cap laminated with reinforced thermoplastic synthetic resin mixed with carbide, glass fiber, glass flakes, aromatic polyamide fiber, etc., to obtain extremely high adhesive strength with the metal or thermoplastic resin. I can do it.

Moreover, since chlorinated polyethylene with a chlorination content of about 45% has the maximum internal loss at room temperature, it has the most remarkable effect of effectively suppressing resonance, which is a drawback of a rigid diaphragm.

Furthermore, by mixing the chlorinated polyethylene with polyethylene, it is possible to increase the adhesive strength compared to polyethylene alone, and it is possible to minimize the loss of the physical properties of polyethylene. Also, chlorinated polypropylene, which is another chlorinated polyolefin, may be mixed.

Although the above explanation has been made regarding chlorinated polyethylene, the same effect can be obtained also with chlorinated polypropylene.

As explained above, the present invention is a dust cap made of a chlorinated polyolefin or a composite that includes the chlorinated polyolefin as a part of the structure, and it is possible to improve adhesion without involving any other processing steps. It becomes possible,
I was able to assemble it in the same way as before.

On the other hand, the dust cap has an extremely large internal loss, and as mentioned above, it has a very large shape rigidity, and by having a composite structure as mentioned above, it has a high rigidity and a large internal loss. It is possible to have both.

Therefore, since the speaker equipped with the dust camp according to the present invention has a large internal loss, the resonance suppressing effect of the dust cap is remarkable, so it is possible to prevent an adverse effect on the frequency characteristics of the speaker, and the cone paper 8 and It has a remarkable effect of supplementing the strength of the coil bobbin 6 in the radial direction and suppressing abnormal noises caused by gap deviation due to bell vibrations, voice coil short-circuit accidents, etc.

[Brief explanation of drawings]

The drawing is a cross-sectional view of a cone-shaped speaker.

Claims (1)

[Claims] 1. Claim 1, which is characterized by a dust cap for a speaker, which is characterized by being formed from a chlorinated polyolefin resin or a composite material comprising the same as a part of the structure. Dust cap for the speaker listed. 3. Patent claim 1, characterized in that the composite is made by layering a thermoplastic/plastic resin with a higher Young's modulus or a reinforced thermoplastic/plastic resin on the surface of a chlorinated polyolefin resin. Dust cap for the speaker listed. 4. The dust cap for a speaker according to claim 1, wherein the composite is a mixture of a chlorinated polyolefin resin and a polyolefin resin.