JP3030904B2 - Speaker diaphragm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm for a speaker used in various audio equipment.

[0002]

2. Description of the Related Art Conventionally, a fixed edge of 100% natural pulp integrated with a diaphragm main body is used as an edge base material of a conventional speaker diaphragm, and a natural pulp sheet or SBR is used as a free edge bonded to a cone portion. Woven fabric, urethane foam, etc. impregnated with resins such as NBR and NBR.

[0003]

Since the fixed edge is integrated with the diaphragm main body, the amplitude cannot be obtained, and the lowest resonance frequency (f _o ) cannot be lowered, so that heavy bass reproduction cannot be performed. The free edge using a natural pulp sheet has a low power input because the strength of the material is weak. SBR, drawbacks such woven fabric impregnated with resin such as NBR are weak in humidity resistance and heat resistance, also due to poor amplitude linearity for the input, a large rate of decrease in the lowest resonance frequency f _o at high input resistance was there.

Further, urethane foams have disadvantages such as low humidity, heat and weather resistance. In some cases, SBR or acrylic coatings were formed on the surface of the urethane foam. SBR coatings are susceptible to deterioration in physical properties under the influence of temperature and humidity. The acrylic coating has a drawback that thermoforming is difficult due to the difference in physical properties from the urethane foam.

[0005] The present invention removes the deficiencies of the prior art as described above, heat, moisture, excellent in reliability such as weather, a little edge portion of reduction rate of a high withstand lowest resonance without deformation even when the input frequency f _o It is an object of the present invention to provide a speaker diaphragm having the same.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a moisture-curable urethane film layer using an ether polyol on the surface or both surfaces of an ether urethane foam, An edge is formed by impregnating the emulsion and heat-molding to form an edge, and is connected to a peripheral portion of the diaphragm main body to form a speaker diaphragm.

[0007]

[Function] As described above, by providing a moisture-curable ether-based urethane coating layer on the surface or both surfaces of an ether-based urethane foam having better wet heat property than the ester-based urethane foam, deterioration of physical properties due to ultraviolet rays can be prevented. It is possible to prevent and improve reliability. Furthermore, waterproofness is also given by impregnating the emulsion.

[0008]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a speaker diaphragm according to the present invention. Reference numeral 1 denotes an edge portion, and reference numeral 2 denotes a diaphragm main body. The edge portion 1 of the diaphragm has a configuration in which a moisture-curable urethane coating layer is provided on an ether-based urethane foam base material.

The conditions for forming the surface coating are as follows. The polyol part is weighed, isocyanate is gradually added, the temperature is slowly raised, and the reaction is carried out at 85 ° C. for 2.5 hours. This is sheeted on a release paper by a predetermined amount, and then urethane foam is placed thereon to be integrated. 60 ~ 80 ℃
After solidifying for 2 to 4 minutes in an oven set to 80,
Aftercure at ~ 110 ° C for 4-8 minutes to about 50μ
Is formed to form the edge portion 1. The whole is impregnated with a rosin-based emulsion and dried.
The above urethane foam was molded into the edge portion 1 shown in FIG. 1 under the conditions of a mold temperature of 190 ° C. and a molding time of about 40 sec, and the diaphragm main body 2 was adhered to the inner peripheral portion.

FIGS. 2 and 3 show the results of a weather resistance test using the speaker diaphragm of the present invention. Edge part 1 of the present invention
Is better in both tensile strength and elongation retention than conventional products using urethane foam edges. Also, the waterproofness becomes very good.

[0012]

As described above, since the speaker diaphragm of the present invention is constituted, the moldability is excellent and the weather resistance and the waterproofness are excellent because the base material and the coating on the edge are made of the same urethane. Thus, a speaker capable of providing a large input can be provided with great industrial value.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a speaker diaphragm according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing tensile strength retention by a weather resistance test of a speaker using the speaker diaphragm of the present invention.

FIG. 3 is a characteristic diagram showing the elongation retention.

[Explanation of symbols]

 1 edge part 2 diaphragm main body

Claims (1)

(57) [Claims] 1. A loudspeaker comprising a moisture-curable ether-based urethane film layer formed on the surface or both surfaces of an ether-based urethane foam, impregnated with a rosin-based emulsion, and heat-molded edges connected to the peripheral edge of the diaphragm main body. Diaphragm.