JPS58106993A - Diaphragm of speaker - Google Patents

Abstract

PURPOSE:To obtain a diaphragm of a speaker which has a high specific elastic modulus and a large internal loss, by laminating a skin material having a high elastic modulus on the surface of a rubber composition which has a foaming structure by converting a natural rubber to an ebonite or hardening the natural rubber. CONSTITUTION:100pts. natural rubber, 1pt. stearic acid, 5pts. zinc oxide, 20pts. carbon black, 6pts. azodicarbonamide, 1.5pts. urea blowing assistant, and 40pts. sulfur are mixed, and this mixture is moved into a primary mold and is vulcanized for about 4min at a temperature of about 150 deg.C. As the result, foaming is caused simultaneously with bridge formation, and a sponge-shaped primary vulcanized material indicating the rubber elasticity is obtained. This primary vulcanized material is moved to a secondary mold, and at this time, skin materials having a high elastic modulus are placed on front and rear faces of the primarily vulcanized rubber composition. The secondary mold is closed, and the primary vulcanized material is vulcanized again for 40min at a temperature of about 170 deg.C. As the result, foaming and conversion to ebonite in a required degree are caused in the mold of the rubber composition, and skin materials are molded as one body, and thus, a diaphragm where skin materials are laminated on surfaces of the rubber composition of the hard foaming material and the specific elastic modulus is high and the internal loss is large is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker diaphragm made of a rubber composition and bonded with a sheet made of a material having a higher elastic modulus to form a multilayer structure with improved characteristics. This invention is an improvement on the invention of Japanese Patent Application No. 56-45441 filed in Hikari.

Conventionally, materials used for speaker diaphragms include paper, aluminum, aluminum honeycomb, polymer graphite, and foamed metal.

These materials meet the requirements for the diaphragm of a speaker, namely ([) high specific elastic modulus B4= (E: Young's modulus, /): density U), (it) large internal loss, We devised the shape, thickness, etc. to satisfy the following.
Designed to maximize performance as a speaker diaphragm.

However, the upper limit of the characteristics of this diaphragm is determined by the material used, so if the same material is used, no dramatic improvement in performance can be expected.

In order to provide a completely new speaker diaphragm with high performance that cannot be obtained with conventional materials, we focused on using a rubber composition as a material. That is, in general, rubber has a very small Young's modulus as it is, but if it is hardened by adding sulfur to form ebonite, the Young's modulus increases. Furthermore, by foaming this hardened rubber, the paper density β also decreases and the specific elastic modulus B/r increases. Furthermore, since 1 rubber is an amorphous material, various reinforcing materials and chemicals can be added.
By performing such addition, the internal loss l can be increased. From this point of view, the invention previously proposed by the present applicant involves hardening natural rubber or synthetic rubber by making it ebonite, reinforcing it by adding an organic or inorganic reinforcing material, or by combining both of these means, and then foaming it. Since the speaker diaphragm is made of a structured rubber composition, it is possible to reduce the size of the speaker.

In other words, if the material is moth, β is 0.5, and even if it is aluminum honeycomb, β is in the practical range of 0.1 to 0.15, but in the case of rubber composite BK material, it is practical to set β to 0.1 or less. Therefore, it is advantageous to increase the specific modulus of elasticity. (
b) Since the thickness of the diaphragm can be made thicker, it is possible to reduce split vibration, and it is possible to construct a speaker that can reproduce reproduced sound with extremely low distortion. (/1 Design flexibility is high. In other words, since the base material is rubber, various additives can be used. By changing the additives, the physical properties of the diaphragm and the character of the reproduced sound can be changed to the market. It can be changed freely to suit your needs.Also, depending on the application, you can create a speaker unit with optimal characteristics for any speaker unit, from bass to treble.Furthermore, since it is molded by melting, there are no restrictions on the shape. Since it can be made into various shapes such as a cone shape and a planar shape, it has the advantage that it can be manufactured with the desired performance in terms of directivity and phase characteristics.

However, the present applicant believes that while the previously presented invention has many features like Jin, it suffers from an internal loss! Although it is desirable to increase both Young's modulus and E, the density I
There is a problem that when the Young's modulus is decreased, the Young's modulus itself becomes smaller, and there is room for improvement in this point.9.

This invention was made by focusing on the above-mentioned problems.
Turn natural rubber or synthetic rubber into ebonite or inorganic rubber.
*Reinforcement by adding a mechanical reinforcing agent or a combination of these two methods to harden and foam the surface of the rubber composition.
The purpose is to solve the above-mentioned problems by forming a structure in which skin materials having a large elastic modulus are laminated.

This invention will be explained in detail below.

The composition of the rubber composition used in this invention is, for example, natural rubber 1
00 Mu Sobe (Hereinafter, all parts indicate heavy wax parts) Stearic acid 1sX1!1! Zinc oxide 5 parts, carbon black 20 parts, azodicarbonamide 6 parts, urea foaming aid 1
．． There are 5 capitals and 40 parts of sulfur.

For example, styrene butadiene rubber (SBI-L) 10
0 parts, stearin version 1 part, 5 parts of oxidizing lead, 50 parts of Rikibo/Black, 6 parts of DNPT, 0.6 part of urea-based foaming aid,
Consists of 30 parts of sulfur. Alternatively, nitrile butadiene rubber (NBR) 10041115, phenol 848m
50 parts, stearin eR 1 part, zinc oxide 5 parts, carbon black 10 parts, sulfur 5 parts, DMI part, ADCA 6 parts, and urea foaming aid 0.6 part.

The material used to manufacture the skin material used in this invention has a Young's modulus of 5 x 10"N/- or more, and a specific elastic modulus of lX
10'#/- or more.

If the Young's modulus and specific modulus of elasticity are below the above values, the Young's modulus of the skin layer made of the rubber composition alone is about 1O"N/d, so there is no reinforcing effect. Therefore, it is not effective in improving the performance of the diaphragm. Some have a Young's modulus of 5 x 10"N7w1 or more, and even if the Young's modulus is large, heavy materials make the speaker diaphragm heavy and deteriorate performance, so the specific elastic modulus is 1 x 10.
Anything above 'd/-' is suitable as a skin material.

For example, a metal sheet that satisfies the above requirements and can be used as the skin material of the present invention.

The metals mentioned above are, for example, pure metals such as beryllium, aluminum, titanium 1, boron, and alloys thereof.

Furthermore, various fibers such as inorganic fibers and organic fibers can be used. Examples of fibers include carbon fiber, glass fiber,
In addition to potassium titanate single crystal fibers, carbonized/silicon fibers, asbestos fibers, aromatic polyamide fibers, etc., it also includes various whiskers.

That is, the skin material may be a so-called cloth-like sheet such as a woven fabric or a non-woven fabric made of the above-mentioned various fibers, or a composite material sheet containing 10 wt% or more of the above-mentioned various fibers, such as F'R, P, F' RTP.

It is also possible to use FRM, a sheet made from the above-mentioned various short fibers together with a thermosetting resin and Vailp fibers.

For example, graphite, mica, calcium carbonate, Merck (calcium powder), etc. can also be used.

That is, the skin material may be a laminated sheet or sintered sheet of the above-mentioned inorganic filler, or the above-mentioned inorganic filler material may be used. A composite sheet containing 10wt or more of A-based material can be used.

This invention will be described in detail below with reference to Examples, but the invention is not limited to these Examples.

[Example 1] 100 parts of natural rubber, 1 part of stearic acid, 5 parts of zinc oxide,
20 parts of carbon black, 1 azodicarbonamide 6s
After mixing 1.5 parts of a urea-based foaming aid and 40 parts of sulfur using a mixer, the mixture was transferred into a puja mold and vulcanized at a temperature of 150 DEG C. for 4 minutes. As a result, foaming occurs at the same time as crosslinking, and a sponge-shaped primary vulcanizate exhibiting rubber elasticity is obtained. Next, this secondary vulcanizate is transferred into a secondary mold, and at this time, a separately manufactured skin material, that is, a single carbon fiber, is
Place a phenolic resin-impregnated sheet containing 0wt on the upper and lower surfaces of the primary vulcanized rubber composition. Close the secondary mold and heat at 170°C.
Reheat for 40 minutes at a temperature of . As a result, foaming and ebonization occur to the extent necessary for molding the rubber composition, and since the skin material is integrally molded, the diaphragm is a molded product in which the skin material is pressed onto the surface of the hard foam rubber composition. can get. The density and Young's modulus of the obtained laminate molded product and the rubber composition alone molded under the same conditions were as follows.

Next, only the skin material was replaced with a material other than the phenolic resin-impregnated sheet containing 5091 carbon single fibers of the first example, and the other conditions were the same as above to obtain a laminate molded product. The results were as follows.

[Example 9] Using the same rubber composition material as in Example 1, a primary vulcanizate is obtained in the same manner as above. The obtained primary vulcanizate is transferred into a secondary mold and similarly re-vulcanized at 170° C. for 40 minutes to obtain a secondary molded product containing only the rubber composition. Next, aluminum foil with a thickness of 30 μm is bonded as a skin material to the surface of the rubber composition after secondary molding using an epoxy adhesive. As a result, an image plate having a skin material laminated on the surface of a hard foam rubber composition is provided. The density and Young's modulus of a single rubber composition molded under the same conditions as the obtained laminate molded product were as follows:0 Note that only the skin material was replaced with other materials other than the thickness of 30 μm in Example 9 above. , Other string properties were obtained in the same manner as in Example 9, and the results of each Example were as follows.

As shown in the above example, in order to laminate a skin material on the surface of a diaphragm manufactured from a rubber composition, it is necessary to mold it or to place the skin material on the opposite side of the rubber composition that has completed secondary molding. It may be attached using adhesive. Which method is selected is determined by taking into consideration the mutual fit between the rubber composition and the skin material.

The thus obtained diaphragm of the rubber composition and the skin material has almost the same internal loss as the diaphragm made of the rubber composition. Moreover, Young's modulus can be increased by 3 to 5 times.

As explained above, according to the present invention, the structure of the diaphragm of a speaker is made hard by converting natural rubber or synthetic rubber into ebonite, by adding an organic reinforcing agent, or by using a combination of these two methods. Since a skin material with a large Young's modulus is laminated on the surface of a foamed rubber composition, the Young's modulus (density ψ is large) is small, so B/7=is extremely 1. It is possible to provide a high-performance speaker diaphragm that is large in size and has a large internal loss.Furthermore, by increasing the thickness and reducing the split vibration, extremely low distortion sound can be obtained. This has the effect of providing a speaker diaphragm that has a high degree of freedom in design and has optimal characteristics that meet market needs. In addition,
1 Speaker in this invention is a device that generates sound by vibrating air, and also includes a sounding body such as an ultrasonic transmitter.〇 (11647-P) Procedural amendment (11030-P) 1972 October 288 2. Name of the invention Speaker diaphragm 3 Relationship to the case of the person making the amendment Applicant address - M - 1-13-13-6 Higashigami Wf 1-chome, Taito-ku, Tokyo
, Number of inventions increased by the amendment 7, Subject of the amendment Specification, rare - 1 (Detailed explanation of the invention column) 8. Contents of the amendment As shown in the attached sheet 8. Contents of the amendment (1) Page 3 of the specification In the second and third lines, "the internal loss is large" is corrected to "1, the internal loss η is large."

Claims (1)

[Scope of Claims] Ill A rubber composition in which natural rubber or synthetic rubber is hardened by evocite formation, reinforcement by addition of an organic or inorganic reinforcing material, or a combination of these means to form a foamed structure, and the surface of the rubber composition has elastic properties. A speaker diaphragm characterized by piling up materials with a high ratio. (2) The diaphragm for a speaker according to claim 1, wherein the skin material is made of gold S having a Young's modulus of 5×1ON/7 or more and a specific elastic modulus of I×10′17w-2 or more. (3) The skin material has a Young's modulus of 5 x 101ON 7
2. The diaphragm for a speaker according to claim 1, wherein the diaphragm is made of an inorganic or organic fiber having a specific elastic modulus of I x 10' d/- or more and a specific elastic modulus of I x 10' d/- or more. (4) The skin material is a sheet of a composite material containing 10wt1 or more of inorganic or organic fibers having a Young's modulus of 5×10”N/ze or more and a specific elastic modulus of I×107wt7wz or more.Claim 1 The diaphragm of the speaker used in the competition.
/pi and specific elastic modulus 'Xl 0'wt/-z'
No more than that! A diaphragm for a speaker that is made of a material sheet or a sintered sheet. (6) Young's modulus for the front 8 Biskin system is 5 x 10”N/j
2. A diaphragm for a speaker according to claim 1, which is a composite sheet containing 10 wt or more of the unscrupulous diaphragm having a specific elastic modulus of I x 107 b/-' or more.