JPH04213998A - Dust cap of speaker - Google Patents

Abstract

PURPOSE:To provide the speaker dust cap which has strength to moisture and heat, maintains shape holding power and has a vibration absorbing property. CONSTITUTION:The woven fabric of polymethaphenylene isophthal amide fibers is used as a base material (1) and a resin material (2) for vibration absorption is disposed on and in the front surface and weaving mesh holes thereof.

Description

Description: [0001] The present invention relates to a speaker dust cap that is stable against moisture and heat, has little deformation, is lightweight, and has high input resistance. [0002] As shown in FIG. 4, the structure of a general dynamic speaker is such that a vibration is generated in an annular magnetic gap (9a) formed by a magnetic circuit (9) incorporating a magnet (10). The voice coil (8) attached to the tip of the plate (6)
) is suspended and supported by a frame (7) by an edge (15) attached to the outer edge of the damper (11) and the diaphragm (6). Therefore, a dome-shaped dust cap (5) is pasted on the upper surface of the diaphragm (6) near the base of the voice coil (8), and the annular magnetic gap (
9a) to prevent foreign matter such as iron powder from entering. [0003] Therefore, the diaphragm (6) vibrates together with the dust cap (5), and acts as an additional mass in terms of vibration. And the vibration of the diaphragm (6) is
It is transmitted directly to the dust cap (5), causing noise in the dust cap (5) itself, or causing noise in the dust cap (5).
The vibration of 5) is reflected back to the diaphragm (6) and
6), so the speaker dust cap (5) not only protects from contaminants, but also greatly affects the quality of the speaker's playback sound. Therefore, the dust cap (5) is attached to the diaphragm (
6) as a diaphragm (6) as an acoustic radiator.
A function that supports this is desired. [0004] Conventional speaker dust caps are made of synthetic fiber fabric, which is less deformed by humidity than cotton fabric, as a base material. In practical use, it is impregnated with a vibration absorbing agent such as acrylic resin placed in the holes in the surface and texture. [0005] Problem to be Solved by the Invention: These conventional speaker dust caps have the problem that when the diaphragm is made of a material with good thermal conductivity such as carbon fiber or aluminum sheet, the heat generated from the voice coil is not transmitted. Heat resistance is required, as there are problems such as deformation and defective air gap rubbing. [Means for Solving the Problems] The present invention eliminates the above-mentioned drawbacks, and has excellent heat resistance and moisture resistance, does not soften even with large inputs, has little change in shape, and has excellent heat resistance and moisture resistance. Therefore, it is a highly durable speaker dust cap that does not adversely affect frequency characteristics. As shown in the cross section of FIG. 1, the structure is a speaker dust cap in which a woven fabric of polymetaphenylene isophthalamide fiber is used as a base material, and a vibration-absorbing resin agent is disposed on the surface and inside the holes in the weave. [Function] Since the speaker dust cap of the present invention has the above-described structure, the fabric of the base material is constructed by utilizing the excellent water resistance and heat resistance properties of polymetaphenylene isophthalamide fiber. The vibration-absorbing properties of the vibration-absorbing resin placed on its surface and in the textured holes make it resistant to moisture and heat, making it a dust cap that is stable against heat and moisture and has sufficient shape retention as a speaker dust cap. You can get it. [Embodiment] The present invention will be explained based on the embodiment shown in FIG. (1) is a textile base material, consisting of warp (1a) and weft (1b), warp (1a) x weft (1b)
A polymetaphenylene isophthalamide fiber fabric of 60 x 60 fibers/inch and 96 g/m2 was impregnated with 10% methanol solution phenolic resin and dried with hot air to produce 112 g.
A coat with a total weight of 169 g/m2 was obtained by obtaining a phenol-impregnated textile base material (A) of 169 g/m2, coating its surface and inside the weave holes with a butyl acrylate resin emulsion as an absorbent using a knife coater, and drying with hot air. It is cloth ■. [0009] Similarly, 75 x 75 pieces, 87 g/m2
The polyethylene terephthalate fiber fabric was treated in the same manner as above to obtain a coated fabric (2) with a total weight of 169 g/m2. Then, the coated cloth (1) was heated at 205°C and the coated cloth (2) was heated at 190°C for 15 seconds in a mold and pressure molded to form a similar dome-shaped dust cap (101) with a diameter of 94 mm and a height of 17 mm. , (102) was obtained. [0010] The dust cap thus obtained (10
1), (102) were left in an atmosphere of 130°C for 12 hours, and the change in the flatness of the outer periphery of the lower end of the dome due to thermal deformation was measured using a thickness gauge (t) using the method shown in Figure 2. are shown in Table 1. In this way, the dust cap (101) has almost no gaps, and the dust cap (102) is highly deformed. Also, dust cap (101), (1
Figure 3 shows how the Young's modulus of the material 02) changes with temperature.
The heat shrinkage rates are shown in Table 2. Based on the above, there is almost no difference between the two at 30 to 70°C, but at 100 to 130°C, the dust cap (10
It can be seen that 1) has a stronger shape retention ability at high temperatures. [Table 1] [Table 2] [Effects of the Invention] Due to the above structure, the speaker dust cap of the present invention has excellent water resistance and heat resistance of polymetaphenylene isophthalamide fiber. The fabric of the base material is skillfully utilized, and the vibration-absorbing properties of the vibration-absorbing resin placed on its surface and in the holes in the texture make it resistant to moisture and heat, and can be used as a speaker dust cap to absorb heat and moisture. Since the dust cap is stable and has sufficient shape retention, it is possible to obtain stable sound reproduction quality and sufficient input resistance from the speaker.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional model diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a method for measuring flatness.

FIG. 3 is a diagram showing changes in Young's modulus versus temperature.

FIG. 4 is a cross-sectional view of a dynamic speaker.

[Explanation of symbols]

(1) Resin-impregnated textile base material (2) Resin agent for vibration absorption

Claims (1)

[Claims] 1. A dust cap for a speaker, which uses a polymetaphenylene isophthalamide fiber fabric as a base material, and has a vibration-absorbing resin agent disposed on the surface and inside the holes in the texture.