JP2003078998A - Support system component for electroacoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support system component for an electroacoustic transducer with a thinner configuration, reduced weight, ensured flexibility and heat resistance, without possibility of deformation, compatible with various color tones, with ease of manufacture at low costs. SOLUTION: Polypropylene is blended to styrene group thermoplastic elastomer to obtain a composition, which is sheet-processed by the calendar system. The sheeted material is formed by the vacuum forming method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support system component for an electroacoustic transducer such as an edge or a damper for supporting a diaphragm such as a speaker or a microphone.

[0002]

2. Description of the Related Art An edge of an electroacoustic transducer such as a speaker has, for example, good linearity with respect to an input, is unlikely to cause an inverse resonance phenomenon, is lightweight, and is easy and inexpensive to manufacture. Etc.

From this point of view, as the material of the free edge in which the diaphragm body and the edge portion are made of different materials,
Vulcanized rubber edges are relatively well used because they are flexible, have excellent vibration absorption, have high bending fatigue resistance, have high heat resistance, and have excellent waterproofness.

However, due to the global environment and the like, recently, there has been a tendency to attach importance to measures against environmental problems, but this vulcanized rubber edge is difficult to recycle,
Also, in the manufacturing process, the molding time (vulcanization) is relatively long, the manufacturing energy is large, and the degree of contamination of the mold is severe, so that the mold maintenance cost such as the mold cleaning process becomes expensive. I'm holding.

One of the solutions to these drawbacks of the vulcanized rubber edge is a thermoplastic elastomer.

Among these thermoplastic elastomers, the so-called olefin elastomers made of PP (polypropylene) and EPDM (ethylene / propylene / gen terpolymer rubber) are particularly environmentally friendly and relatively thick. Those with high hardness have heat resistance enough to withstand in-vehicle use, but those with thinner walls in order to comply with high compliance and those with lower hardness are prone to deformation, resulting in poor heat resistance. It has a drawback that it will end up.

[0007] The process of manufacturing a support system component for an electroacoustic transducer using this thermoplastic elastomer is as follows: pellet → molded pellet by injection molding into a predetermined shape → extruded sheet molding → molded pellet by a concavo-convex matching mold into a predetermined shape → Extrusion sheet molding → vacuum forming to a predetermined shape is mainly used.

[0008]

The method of [Problems to be Solved by the Invention] is excellent in terms of cost and flexibility of product shape, and in some cases, simultaneous molding and bonding with other parts (such as the diaphragm body and gasket) is possible. Therefore, it is a relatively excellent molding method. However, if residual stress and molding shrinkage at the time of molding are sufficiently calculated and production is performed without establishing the optimum mold structure and molding conditions, problems of product variations such as deformation will occur.

In the method of (1), the degree of freedom of the product shape and the simultaneous bonding with other parts (for example, the vibration plate main body and the gasket) are difficult, but the molding die is inexpensive and the manufacturing process is simple. Moreover, since there is little variation in products, it is possible to stably obtain inexpensive products. But,
Since the sheet is produced by extrusion, it is difficult to produce a thin sheet (stable level is 0.30).
However, it is difficult to meet the requirements for light weight and high compliance, which are increasing in demand due to the recent miniaturization of speakers. In addition, the one that requires high compliance and has a low hardness has a low heat resistance, and is not suitable for in-vehicle use.

There is also a method in which the sheet is thinned by stretching, but the sheet produced by this method has a large directionality and therefore has a drawback that it is easily deformed.

Further, in the extrusion type sheet forming, it takes time to change colors due to the mechanism of the machine, and the cost becomes high when trying to cope with various color tones.

In addition to the method of the method (1), the edge forming die is inexpensive and the manufacturing process is simple. Further, since it is easy to develop into a large number of pieces, a more excellent method for forming a supporting system component is obtained, but the drawbacks are the same.

The present invention has been proposed in view of the above, and an object thereof is to make it thinner, to reduce the weight, to ensure flexibility and heat resistance, and to possibly deform it. It is another object of the present invention to provide a support system component for an electroacoustic transducer that is easy to manufacture and that can cope with various color tones and that is inexpensive.

[0014]

According to the present invention, a composition in which polypropylene is blended into a styrene thermoplastic elastomer having a hard segment made of polystyrene and a soft segment made of an ethylene / propylene copolymer is molded into a predetermined shape, It has achieved the above objectives.

Further, in this case, a sheet material obtained by forming the composition into a sheet by a calendar method is formed into a predetermined shape.

The sheet material is characterized by being formed by a vacuum forming method.

A conventional support system component formed by injection molding using a thermoplastic elastomer of polypropylene and EPDM as a raw material is apt to be deformed at the time of molding, resulting in a serious problem in manufacturing stability. In addition, a support system component that is formed by extruding this material into a sheet and then shaping this sheet into a predetermined shape has less deformation during molding and can simplify the manufacturing process, but it is difficult to produce a thin sheet and high compliance It was difficult to deal with. Also,
Those that have been thinned by stretching or made high compliance by lowering the hardness tend to be deformed, resulting in reduced heat resistance, and for applications that require heat resistance such as in-vehicle use. Was unsuitable.

On the other hand, in the present invention, a composition in which polypropylene is blended with a styrene-based thermoplastic elastomer in which the hard segment is composed of polystyrene and the soft segment is composed of ethylene / propylene copolymer is molded into a predetermined shape to obtain high compliance. It is possible to provide a support system component having excellent heat resistance.

Further, by forming this composition into a sheet by using a calendering method, a thin-walled sheet having less directivity can be produced. By molding this composition into a predetermined shape, it is lightweight, has high compliance and little deformation. A support system component having high heat resistance can be provided. Further, since the color change can be performed relatively easily in the calendar method, it is possible to meet the recent demand for designability at low cost.

Further, in the case where this sheet is formed into a predetermined shape by using the vacuum forming method, the die is inexpensive, the manufacturing process can be simplified, and a large number of pieces can be easily obtained. In addition, excellent productivity can be added.

[0021]

EXAMPLES A method of manufacturing a support system component for an electroacoustic transducer according to an example of the present invention will be described below.

In the present invention, polypropylene is blended with a thermoplastic polymer whose hard segment is polystyrene and whose soft segment is ethylene-propylene polymer. That is, as the thermoplastic polymer, 40 parts by weight of a styrene-based elastomer (trade name Septon 4055 manufactured by Kuraray Co., Ltd.) and polypropylene (trade name PH943B manufactured by Nippon Polyolefin) are added thereto.
20 parts by weight, 40 parts by weight of paraffin oil, and other antioxidants and ultraviolet absorbers are charged into a mixer (not shown) having a well-known structure and heated and kneaded.

Next, the kneaded product is sheeted by a calendar method.

As shown in FIG. 1, the periphery of the sheet material 1 formed into a sheet is supported by a support member 2 and heated in an infrared furnace (heating in the furnace at 200 ° C. for 6.5 seconds). In the figure, 3 is an infrared source. The sheet material 1 is softened by the heating by the infrared source 3.

The heated sheet material 1 is immediately placed on the vacuum forming die 4 as shown in FIG. 2 and is attached to the vacuum forming die 4 by vacuuming as shown in FIG. Form the sheet. (This time, vacuum strength of vacuum pump: 20
0 mmHg, vacuuming time: 10 seconds).

Thereafter, as shown in FIG. 4, the molded product is cooled by forced air cooling by a blower (not shown) (10).
Seconds).

Then, as shown in FIG. 5, air is sent from the vacuuming path to release the molded product 1A.

As shown in FIG. 6, the inner periphery and the outer periphery of the molded product 1A are trimmed to a predetermined size to produce, for example, an edge material 5.

Then, as shown in FIG. 7, the outer peripheral portion of the diaphragm body 6 is adhered to the speaker edge member 5 to obtain a speaker diaphragm.

The features of the product of the present invention thus produced are as follows.

Conventional olefin elastomer (EPD
Compared to an edge material prepared by extruding a thermoplastic elastomer in which M is a soft segment and polypropylene is a hard segment, polypropylene is a polypropylene-based styrene thermoplastic elastomer in which the hard segment is polystyrene and the soft segment is ethylene-propylene copolymer. In the product of the present invention, which is made by using a composition in which the above is blended, and which is formed into a sheet by using a vacuum forming method, since it is thinner (resulting in a lighter weight) and flexible,
When used as a speaker, fo can be lowered. By the way, the conventional product (edge material formed by extruding a thermoplastic elastomer having EPDM as a soft segment and polypropylene as a hard segment by an extrusion method) had a limit of 0.3 mm, but the product of the present invention has a thin wall thickness of 0.1 mm. The sheet of could be produced.

Further, the edge material 5 has excellent heat resistance and, as shown in Table 1 below, has more excellent heat resistance than the conventional product, so that the edge material 5 is stable even under severe temperature conditions such as a car. Performance can be obtained over a long period of time. Table 1

Further, the edge material 5 has less temperature dependency as compared with the conventional product, and when used in a speaker,
As shown in Table 2 below, there is little change in the fo of the speaker with respect to temperature, and stable acoustic performance can be obtained in a wide temperature range. Table 2

FIG. 8 shows the f of the speaker of the present invention and the speaker of the conventional product.
The temperature dependence of o is shown.

In the above embodiment, an example of forming the edge member 5 as the supporting system component has been described. However, other supporting system components, that is, dampers can be prepared in substantially the same manner, and a damper having similar physical properties can be used. Obtainable.

[0036]

As described above, according to the present invention, a composition in which polypropylene is blended with a styrene thermoplastic elastomer whose hard segment is polystyrene and whose soft segment is ethylene / propylene copolymer is molded into a predetermined shape. To provide a support system component for an electroacoustic transducer that is thin, and therefore flexible, has high flex fatigue resistance, is excellent in weather resistance, heat resistance, waterproofness, and is environmentally friendly. You can

Further, by forming the composition into a sheet by using a calendar system, a thin sheet can be easily produced (up to 0.1 mm), and the demand has been increasing due to the recent miniaturization of the speaker. It is lightweight and supports high compliance. Also, since there is little directionality,
Deformation is hard to occur. Further, as compared with the extrusion type sheet forming, the color change is easy, so that various color tones can be dealt with at low cost.

Further, by molding the above-mentioned sheet material using a vacuum forming method, it is possible to reduce the die cost and the manufacturing cost.

Further, since the sheet material obtained with this constitution can be colored freely and, moreover, the sheeting method of the calendar system is used, it is possible to flexibly deal with small lot toning varieties and meet the recent demand for design. Also, it is possible to provide quick response and low cost.

[Brief description of drawings]

FIG. 1 is an explanatory view of a step of manufacturing a support system component for an electroacoustic transducer according to an embodiment of the present invention.

FIG. 2 is an explanatory view of the next manufacturing process of the above.

FIG. 3 is an explanatory view of the next manufacturing process.

FIG. 4 is an explanatory view of the next manufacturing process.

FIG. 5 is an explanatory view of the next manufacturing process.

FIG. 6 is an explanatory view of a final manufacturing process.

FIG. 7 is a schematic explanatory diagram showing a state in which a support portion made according to the present invention is incorporated in a speaker diaphragm.

FIG. 8 shows the temperature dependence of the speaker fo of the present invention and the conventional product.

[Explanation of symbols]

1 sheet material 2 Support parts 3 infrared source 4 Vacuum forming mold 5 Edge material 6 Vibration plate body

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Claims (3)

[Claims] 1. A support system for an electroacoustic transducer, which is obtained by molding a composition obtained by blending polypropylene into a styrene thermoplastic elastomer having a hard segment made of polystyrene and a soft segment made of ethylene / propylene copolymer, in a predetermined shape. parts. 2. A support system component for an electroacoustic transducer, characterized in that a sheet material obtained by forming the composition into a sheet by a calendar method is molded into a predetermined shape. 3. A support system component for an electroacoustic transducer, wherein the sheet material according to claim 2 is formed by a vacuum forming method.