JPH03239098A - Diaphragm for loudspeaker and its manufacture and manufacturing die - Google Patents

Abstract

PURPOSE:To hold internal loss in suitable magnitude, and also, to eliminate the deviation of partial strength and the characteristic by executing compression molding to a film-like member containing at least one of a thermoplastic resin and a thermoplastic elastomer, and a woven cloth-like member containing a high elastic fiber and forming them integrally. CONSTITUTION:The above diaphragm is formed integrally by laminating pan compound carbon fiber woven cloth 1, a polyurethane elastomer film 2, stretching and holding them between molding dies attached to a compression molding machine, and thereafter, pre-heating them by a far infrared radiation ceramic heater 3, and also, fluidizing them by heating of the die and pressurizing and integrating them. The molding die consists of a female die 10 and a male die 20 having the molding die face for installing a laminated sheet material and pressuring and molding it conically, and they are provided with through-holes 11, 21 formed in the axis center part, and annular holes 12, 22 which are formed annularly in the inside of the die and have an entrance port on the outside surface, respectively, the inside of the die is evacuated and deaired, and by allowing vapor to flow into the annular holes 12, 22, the die is heated, and by allowing water to flow, the die is cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diaphragm for a speaker, a method for manufacturing the same, and a mold for manufacturing the same.

[Conventional technology]

There are three typical methods for manufacturing a speaker diaphragm by combining plastics, high elastic fibers, and a third substance for the purpose of improving acoustic characteristics.

(Al thermosetting resin is impregnated into a highly elastic fiber woven fabric, and the semi-cured prepreg is inserted between a pair of heated molds and thermally cured.

(b)! A sheet made by melt-bonding plastic resin powder to high elastic fibers is preheated.

(C) A thermoplastic resin is kneaded with highly elastic fibers or a third substance in the form of powder or scales for improving properties, and the resulting pellet is injection molded.

[Problem to be solved by the invention]

Of the three manufacturing methods mentioned above, when the (al) method is adopted, for example, epoxy resin is used as the thermosetting resin. After curing, this epoxy resin becomes a rigid three-dimensional network molecular structure. Due to its own characteristics, the internal loss is small. Therefore, when composited with high elastic fibers, the internal loss is also small, and good results in terms of sound quality are not necessarily obtained.

In addition, prepregs made by impregnating high elastic fibers with thermosetting resin to a semi-cured state must be stored in a refrigerator in order to delay the progress of the curing reaction.

Furthermore, it took 10 to 15 minutes to heat and cure, resulting in low productivity.

In addition, when method (b) is adopted, the sheet is heated and hardened, and the cooled mold is vacuum-pressed to form the mold, making it difficult to fit the highly rigid composite sheet into the mold. Ta. Furthermore, it was necessary to integrate the high modulus fiber and the thermoplastic resin in advance. Furthermore, it was difficult to press the mold evenly when fitting it into the mold, and the molded product was likely to have uneven thickness.

On the other hand, according to method (C), the reinforcing substance mixed into the matrix reduces the fluidity of the resin.

There is a limit to the amount added (up to about 30% by weight). Also, according to injection molding, the molecular orientation of the resin itself and the orientation of the short fibers in the injection direction are unavoidable, which reduces the strength in the radial direction. It was inevitable that the strength would be significantly lower than the strength in the diameter direction.Also, since it is injection molding, when reinforcing high modulus fibers, it is added in the form of short fibers and cannot be composited into a woven fabric. 1. Local strength and characteristics are biased.

The present invention was made to solve the above problems, and it is possible to maintain internal loss at an appropriate level, eliminate partial deviations in strength and properties, and improve productivity. An object of the present invention is to provide a speaker diaphragm, a method for manufacturing the same, and a mold for manufacturing the same.

[Means to solve the problem]

The speaker diaphragm according to the present invention is formed by compression molding and integrating a film-like member containing at least one of a thermoplastic resin and a thermoplastic elastomer and a woven fabric-like member containing high elastic fibers. .

In this case, it is effective to use a thermoplastic elastomer prepared by heating, melting, and kneading reinforcing materials such as high elastic short fibers or whiskers.

Also, how to manufacture this speaker diaphragm! ! ! A film-like member containing at least one of a plastic resin and a thermoplastic elastomer and a woven fabric-like member containing high-elastic fibers are laminated and stretched between molds for a speaker diaphragm attached to a compression molding machine. After that, these are preheated using a far-infrared ceramic heater or the like, and then the outermost part of the mold is sealed and the inside of the mold is depressurized and degassed.
The film-like member and the woven fabric member are fluidized by heating the mold, and are pressurized with the mold to integrally mold them, and then,
The mold is cooled and the molded part is removed.

Furthermore, the molds used to manufacture this speaker diaphragm consist of a female mold and a male mold, each having a mold surface for pressure forming into a conical shape with a laminated sheet material interposed therebetween. It is preferable to use a mold having a through hole formed in the axial center and an annular hole formed in an annular shape inside the mold and having an entrance and exit on the outer surface.

[Function] A vibration for a speaker obtained by compression molding and integrating a film-like member containing at least one of a thermoplastic resin and a thermoplastic elastomer and a woven fabric-like member containing high-elastic IM fibers as described above. The plate can maintain internal loss to a certain degree larger value than when the epoxy resin is cured, and also has good vibration characteristics without the local unevenness in strength that is inevitable in the case of injection molding. In addition, when using prepreg, there is no need for extra effort such as storing it in the refrigerator to delay the progress of the curing reaction.
This can contribute to improving productivity.

Here, if a material prepared by heating, melting, and kneading reinforcing materials such as high elastic short fibers or whiskers is used as the mature plastic elastomer, the properties can be changed.

In addition, when manufacturing this speaker diaphragm, processability is increased by preheating the laminate of the film-like member and the woven fabric-like member using a far-infrared ceramic heater, etc., and a degassing process is performed during compression molding. By adding steps of heating and cooling the mold, productivity can be significantly improved.

Then, holes are formed in the small parts of the mold and degassed under reduced pressure.
By passing steam through the annular hole to heat the mold and passing water to cool the mold, a speaker diaphragm can be manufactured in an extremely short cycle.

〔Example〕

As shown in FIG. 1(a), the speaker diaphragm according to the present invention is made by laminating a bread-based carbon fiber woven fabric 1 and a polyurethane elastomer film 2, and forming the diaphragm between a mold 312 attached to a compression molding machine. After draping them in the fabric, they are preheated with a far-infrared ceramic heater 3, as shown in Figure 1(b), and then fluidized by heating the mold, as shown in Figure 1(C). At the same time, pressurize and integrate. In this case, preheating with the far-infrared ceramic heater 3 improves workability and at the same time shortens the molding time.

The molding molds include a mold 10 and a male mold 20, each having a mold surface for press-forming into a conical shape with a laminated sheet material interposed therebetween, each of which has a through hole 11 formed in its axial center. ．．
21 and is formed in an annular shape inside the mold.

The mold is provided with an annular hole 12.22 having an entrance and exit on the outer surface, and the inside of the mold is depressurized and degassed through the through hole 11.21.

Steam is passed through the annular hole 12.22 to heat the mold, and water is passed through it to cool the mold. and.

After cooling the mold, the female mold 10 and the male mold 20 are separated, and the molded product 4 is taken out and subjected to post-processing.

Note that steam or water is allowed to flow through the annular hole 12.22 via the switching valve 5.

FIGS. 2(a), 2(b), and 2(c) are a sectional view and a plan view showing the specific structure of the mold. In the figure, a female mold 10 has a conical mold surface 13, a through hole 11 is formed in the axial center of the female mold 10, and five annular holes 12 are formed inside the mold surface 13 along the mold surface 13. There is. Among these, the five annular holes 12 communicate with each other at two locations in the circumferential direction so that the fluid circulates, and the innermost annular hole and the outermost annular hole are connected to the fluid inlet hole 14 and the fluid outlet hole 15 in the circumferential direction. It leads to the sides. In addition, these fluid introduction holes 14 and fluid outlet holes 15
is connected to the aforementioned switching valve 5. Further, bolt holes 16 for fixing the female mold 10 to the molding machine with bolts are provided at four equal positions in the circumferential direction on the outside of the annular hole 12, and bolt holes 16 are provided on the flat surface facing the male mold 20 for positioning. The bosses 11 are also provided at four equal positions in the circumferential direction.

- On the other hand, the male mold 20 also has a conical mold surface 23, and a through hole 21 is formed in the axial center of the mold surface 23.
Five annular holes 22 are formed along the inside thereof. Among these, the five annular holes 22 are connected so that the fluid circulates once, and the innermost annular hole and the outermost annular hole communicate with the circumferential side through a fluid introduction hole 24 and a fluid outlet hole 25. Furthermore, these fluid introduction holes 24 and fluid outlet holes 25 are connected to the aforementioned switching valve 5. Further, bolt holes 26 for fixing the male mold 20 to the molding machine with bolts are provided at four equal positions in the circumferential direction on the outside of the annular hole 22, and are fitted with bosses 17 provided on the tI mold 10. Positioning holes 27 are provided at four equal positions in the circumferential direction.

In particular, a center cap 28 for centering is fitted to the tip of the male mold 20 when viewed from the mold surface 23, and a ring 29 is divided into eight equal parts in the circumferential direction at the base so that the product thickness can be easily changed. screwed in place.

FIG. 3 is a side view of the manufacturing apparatus for the speaker diaphragm. This device mainly consists of a molding machine 30 that attaches a mold and performs pressure molding, a preheating device 40 that preheats the laminated sheet material stretched between the male and female molds 10 and 20, and the outside of the molded product. A press device 50 that removes peripheral edges and unnecessary parts in the center by punching, and a storage device fi60 that stores the punched products.
It is made up of.

Among these, molding 8130 has an upper platen 31 and a lower platen 32 that are integrated by a support, and these are also integrally fixed to a ram cylinder 34 having a ram piston 33, and the ram piston 33 is lowered by hydraulic pressure. It moves up and down through the platen 32, and up to 150
Generates tons of compressive force. The male die 20 is attached to the upper platen 31 via an upper die attachment plate 35. In addition, this upper mold making ff plate 35 has a male mold 20.
A hole 35a is bored through which a pipe connected to the through hole 21 is passed. Further, a holding ring 38 is provided on the lower surface of the upper mold mounting plate 35 and is moved up and down by a small cylinder 31, thereby firmly holding the laminated sheet material. On the other hand, a surface plate is attached to the upper end of the ram piston 33, and the female mold 10 is attached to this surface plate via a lower mold attachment plate 39. Note that this lower mold mounting plate 39 is also provided with a groove 39a through which a pipe connected to the through hole 11 of the female mold 10 passes.

Further, in the preheating device 40, a cylinder 41 is fixed horizontally on a support, and a preheating plate 42 on which a ceramic heater is arranged is attached to the tip of the piston, and when the cylinder 41 is operated, the preheating plate 42 is It extends to the upper surface of the mold 10.

The press device 50 has an upper platen 51 and a lower platen 52 that are integrated by a support. A male punch 53 is attached to the upper platen 51 so as to be movable up and down by a hydraulic cylinder 54, and a male punch 53 is attached to the upper platen 51 so as to be movable up and down by a hydraulic cylinder 54. A female punch 55 is attached. In addition, the press device 5
0 is for a molded speaker, including a vertically moving cylinder,
@Includes a conveying section 56 that depressurizes and adsorbs the moving plate and moves it from the mold position of the molding machine 30 to the female die punch position, and a vertically moving cylinder, and moves the punched product from the female die punch position to the storage device f
Conveying unit 5 to be moved to a predetermined position on storage stand 61 of f160
7, and this conveyance section 56.57 has a conveyance arm 58.
It is designed to be integrally driven by.

The storage device 60 is placed on a storage table 61 with a stacking center 11
62 are planted.

The manufacturing process of a speaker diaphragm using the manufacturing apparatus configured as described above will be described with reference to the case where a speaker diaphragm having a diameter of 2030 is manufactured first.

Bread-based carbon fiber! Trading card C made by Toshi Co., Ltd. as i-woven fabric 1
06343 and Unilon 5-FO manufactured by Japan Unipolymer Co., Ltd. is laminated as the polyurethane elastomer film 2. As a result, a laminated film member containing 50% by weight of carbon fiber and 50% by weight of polyurethane is obtained.

This laminated film member is placed in the molding machine 3 with its center aligned.
0 on the female die 10, and then the cylinder 37 disposed on the upper platen 31 was operated to lower the presser ring 38.

Press the outer edge of the laminated film member with a pressure of about 5 to 30 mm/-.

Next, the cylinder 42 of the preheating device 40 is operated to move the preheating plate 42 on which the ceramic heater is arranged to the upper part of the laminated film member, and the laminated film member is
(After preheating to 1° C., return the preheating plate 42 to the original position shown.

On the other hand, at the same time as the presser ring 38 starts to descend, the switching valve 5 attached to the molding machine 30 is operated to pass steam through the annular holes 12 and 22 of the female mold 10 and the male mold 20. Heat 20 to 180±5℃.

Next, pressurized oil is passed through the ram cylinder 34 of the molding machine 30 to raise the ram piston 33. Regarding this rising, the laminated film member is pressed by the male mold 20 in order from the center part and fits between the female mold 10 and the male mold 20. At this time, the entire outer edge group of the laminated film member is pressed by the presser ring 38. This prevents partial overlapping that is likely to occur during deformation, and enables uniform narrowing.

Next, the ram piston 33 is raised and the parting part of the mold (corresponding to the ring 29 in FIG. 2) is
A pressure of 0 kHz/d is generated to impregnate the carbon fiber l1rH1 with the urethane resin. This makes the inside of the mold airtight. Therefore, the gas inside the mold is sucked through the through hole 11° of the female mold 10 and the through hole 21 of the male mold 20 using a vacuum pump (not shown) to maintain a reduced pressure 1i (755 mHD or less).

Next, stronger pressure (90 to 140 kg/-
) to flow the matrix and impregnate the carbon fibers. Then, before the entire amount of the matrix flows out, the switching valve 5 is switched to allow the cooling water to pass through. As the mold temperature decreases, the shearing force of the matrix increases, and the flow of the matrix eventually stops.

Next, the temperature of the matrix falls below 40°C.

After shaping and solidifying, close the cooling water valve to stop cooling. At the same time, a valve (not shown) connected directly to the vacuum pump is switched to connect it directly to the atmosphere.

Next, at the same time as draining the oil from the ram cylinder 34 of the molding a130, the valve directly connected to the through hole 21 of the male mold 20 is switched to send 5 h/cJ of compressed air into the mold.

This ensures that the molded product adheres to the female mold 10 when the mold is opened.

Next, the ram piston 33 is lowered to a predetermined position.

At the same time as this descent is completed, the valve directly connected to the through hole 21 of the male mold 20 is switched to feed 5 kg/- of compressed air.
As a result, the molded product leaves the mold surface 23 of the male mold 20.

Next, the conveyor arm 58 attached to the press device 50 moves the conveyor section 56 to the center position above the molded product. Therefore, the cylinder of the conveying section 56 is lowered to suck the molded product at the suction port, and then the cylinder is raised to separate the molded product from the male die 20.

Next, the conveying arm 58 moves the conveying section 56 until it comes to the center position of the female punch 55 of the press device 50. Then, the cylinder of the conveying section 56 is lowered, the pressure of the suction port is reduced, the suction is released, and the molded product is transferred to the press device 5.
0 onto the female punch 55, and then the conveying section 56
Yunao raises the suction port of the molded product using a female punch 55.
When the molded product is dropped onto the female punch 55,
The center is aligned.

Next, the conveying arm 58 moves the conveying section 56 to the molding machine 30.
and press device N50, and stop there.

Next, the male punch 53 is lowered by the hydraulic cylinder 54 of the press device 50 to punch out the center hole portion and the peripheral edge portion of the molded product, and then the male punch 53 is raised.

In addition to the punching operation by the press device 50,
In order to obtain the next molded product, the mounting of the laminated film member on the female mold 10 of the molding machine 30 and the subsequent operations are repeated.

In addition to moving and stopping the transport arm 58, the transport unit 5
1 moves to the upper part of the female punch 55 of the press device 50, the cylinder of this conveying section 51 is lowered, and the flat part of the outer edge is sucked by four suction ports. Subsequently, the molded punched product is separated from the female punch 55 by raising the cylinder.

Next, as the transport section 56 moves the next molded product, the transport section 57 moves to the center position of the stock bin of the storage device 60, so at this time, the cylinder of the transport section 57 is lowered to perform suction. Release the negative pressure and raise the cylinder. As a result, the stamped products fall and are stacked.

Next, as described above, the transport arm 5B is moved to the transport section 56.
is moved to a position located between the molding machine 30 and the press device 50 and stopped.

These relationships are shown in a time chart as shown in FIG.

In the above example, one sheet of bread-based carbon kIII textile fabric (Torayka C06343 manufactured by Toshi Co., Ltd.) and one sheet of polyurethane elastomer film (Unilon 5-FO manufactured by Nippon Unipolymer Co., Ltd.) were laminated, and 20 scratches were obtained. This is the manufacturing process for a speaker diaphragm with a different diameter, but by changing the laminated film material,
For example, a polyurethane elastomer film (Lezamin P-1078C, manufactured by Dainichiseika Chemical Co., Ltd.) is attached to two sheets of bread-based carbon fiber woven fabric (Torayca CO6151B manufactured by Toshi Co., Ltd.).
L) is heated and kneaded with aramid short fiber (Kevlar 4941 fiber chop length 9- manufactured by Toshi Shubon Co., Ltd.) using a roll, and the aramid short IIIM1 is crushed and fibrillated and uniformly dispersed in polyurethane. It is also possible to use a film formed by sandwiching and stacking. In this case, carbon fiber is 50% by weight and polyurethane is 40% by weight.
In this case, the aramid short fibers amount to 10% by weight.

Also, by the above molds, devices and methods.

A speaker diaphragm with a diameter of 3010 was manufactured. in this case,
The material used is a piece of bread-based carbon fiber woven fabric.

(Trading Card CO6151B manufactured by Toshi Co., Ltd.), one sheet of Bourethane elastomer film (Unilon 5-FO manufactured by Japan Unipolymer Co., Ltd.), and one sheet of speaker cone paper (cone paper for 30 countries manufactured by Gitsur Co., Ltd.). By using a laminated material of 15g), the carbon edge H1 woven fabric
5% by weight, polyurethane 25% by weight, and cone paper 50% by weight.

An actual speaker was assembled using each speaker diaphragm manufactured as described above, and its characteristics were measured compared to a conventional speaker impregnated with epoxy resin, and the results shown in the table below were obtained.

The frequency characteristics of a diaphragm with a diameter of 20 mm are as shown in Figure 5, and the frequency characteristics of a diaphragm with a diameter of 303 cm are as shown in Figure 5.
As shown in the figure.

As is clear from these tables and characteristic diagrams, the internal loss (tan δ) of this example is significantly improved compared to the conventional product. In other words, the frequency characteristics of the speaker diaphragm are such that the peak of the primary resonance point in the high range is kept low, resulting in smooth characteristics and low second harmonic distortion, resulting in a natural and easy-to-listen sound quality. 6. Also, in the molding of conventional products, a cycle of 10 to 15 minutes was required because a thermosetting resin was used for the matrix, but in this example! If) Since molding can be performed in a 30 second cycle, productivity can be greatly improved.

〔Effect of the invention〕

As is clear from the above description, the speaker diaphragm according to the present invention includes a film-like member containing at least one of a thermoplastic resin and a thermoplastic elastomer;
Since it is integrated with a woven fabric-like member containing high-elastic fibers by compression molding, it is possible to maintain internal loss to a certain degree higher than that of hardened epoxy resin, and it also maintains the strength that is unavoidable in the case of injection molding. Good vibration characteristics can be obtained without any local deviation. Furthermore, when prepreg is used, there is no need to store it in a refrigerator to delay the progress of the curing reaction.

In this case, high elastic short uIi as a thermoplastic elastomer
Properties can be further improved by using reinforcing materials such as fibers or whiskers heated, melted, and kneaded.

In addition, the method for manufacturing a speaker diaphragm according to the present invention increases workability by preheating a laminate of a film-like member and a woven fabric-like member using a far-infrared ceramic heater, etc. Since it includes an air process and mold heating and cooling processes, productivity can be greatly improved.

Furthermore, the mold according to the present invention has a configuration in which a through hole is formed in the shaft center to perform vacuum degassing, steam is passed through the annular hole to heat the mold, and water is passed through the mold to cool the mold. Therefore, speaker diaphragms can be manufactured in an extremely short cycle.

[Brief explanation of drawings]

FIGS. 1(a), (b), and (c) are explanatory diagrams for explaining the schematic structure of the speaker diaphragm of the present invention, and FIG.
Figures (a), (b), and (c) are a cross-sectional view and a plan view showing the configuration of an embodiment of the speaker plate diaphragm manufacturing mold of the present invention,
FIG. 3 is a side view of the above speaker diaphragm manufacturing apparatus, FIG. 4 is a time chart showing the manufacturing process by this manufacturing apparatus, and FIGS. 5 and 6 are frequency characteristics of the speaker diaphragm according to the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1...Bread-based carbon fiber woven fabric, 2...Polyurethane elastomer film, 3...Far-infrared ceramic heater, 10...Female mold, 11.21...Through hole, 12.2
2... Annular hole, 20... Male mold, 30... Molding machine,
40... Preheating device, 50... Pressing device, 60...
・Storage equipment. Figure 2 Figure z9:°Non 7

Claims (4)

[Claims] (1) A speaker diaphragm that is integrally formed with a film-like member containing at least one of a thermoplastic resin and a thermoplastic elastomer and a woven fabric-like member containing high-elastic fibers. (2) The speaker diaphragm according to claim 1, wherein the thermoplastic elastomer is made by heating, melting, and kneading reinforcing materials such as high elastic short fibers or whiskers. (3) A mold for forming a speaker diaphragm, in which a film-like member containing at least one of a thermoplastic resin and a thermoplastic elastomer and a woven fabric-like member containing high-elastic fibers are laminated and attached to a compression molding machine. preheating the film-like member and the woven fabric member stretched and laminated between them, sealing the outermost periphery of the mold, and depressurizing and deaerating the inside of the mold;
A method for manufacturing a speaker diaphragm in which the film-like member and the woven fabric member are fluidized by heating the mold, integrally molded by pressurizing the mold, and the molded member is removed by cooling the mold. . (4) Consists of a female mold and a male mold each having a mold surface that is press-formed into a conical shape with a laminated sheet material interposed therebetween. , an annular hole formed in an annular shape inside the mold and having an entrance and exit on the outer surface, the inside of the mold is depressurized and degassed through the through hole, steam is passed through the annular hole to heat the mold, and water is heated. A mold for manufacturing a speaker diaphragm that has a structure that allows the mold to be cooled by flowing current.