JPH0720311B2 - Manufacturing method of speaker diaphragm and mold for manufacturing the same - Google Patents

Description

The present invention relates to a method for manufacturing a speaker diaphragm and a mold for manufacturing the diaphragm.

[Conventional technology]

There are the following three typical methods for manufacturing a diaphragm for a speaker by compounding a plastic and a highly elastic fiber with a third substance for the purpose of improving acoustic characteristics.

(A) A thermoplastic resin is impregnated into a highly elastic fiber woven cloth, and a cured prepreg is inserted between a pair of heated molds and thermally cured.

(B) Preheat the sheet in which the thermoplastic resin powder is melt-bonded to the high-elasticity fiber.

(C) A thermoplastic resin is kneaded and integrated with a highly elastic fiber or a powder or scale-like third substance for property improvement, and the pelletized one is injection-molded.

[Problems to be Solved by the Invention]

When the method (a) is adopted among the above-mentioned three manufacturing methods, for example, an epoxy resin is used as the thermosetting resin. Since this epoxy resin has a rigid three-dimensional network molecular structure after curing, the internal loss has a small value due to its own characteristics. Therefore, the internal loss in the case of compounding with the high elastic fiber is small, and good results are not always obtained in terms of sound quality. In addition, high elasticity fiber is impregnated with thermoplastic resin,
The semi-cured prepreg had to be stored in a refrigerator in order to delay the progress of the curing reaction, and it took 10 to 15 minutes to be heat-cured, resulting in low productivity.

Further, when the method (b) is adopted, the sheet is heated and hardened, and is suction-pressed and molded in a cooled mold by utilizing a reduced pressure, so that it is difficult to adapt a highly rigid composite sheet to the mold. . Further, it was necessary to previously integrate the high elastic fiber and the thermoplastic resin. Further, it was difficult to uniformly press it when fitting it to the mold, and the thickness of the molded product was likely to be uneven.

On the other hand, according to the method (c), since the reinforcing substance mixed in the matrix lowers the fluidity of the resin, there is a limit to the amount of addition (up to about 30% by weight). Moreover, according to injection molding, molecular orientation of the resin itself in the injection direction and orientation of the short fibers in the injection direction are unavoidable, and it is inevitable that the strength in the radial direction is significantly reduced compared to the strength in the diameter direction. Met. Further, since it is injection molding, when reinforcing the high elastic fiber, it is added in the state of short fiber and cannot be made into a composite as a woven fabric, so that partial strength and unevenness in characteristics occur.

The present invention has been made to solve the above problems, and can maintain internal loss at an appropriate level, eliminate partial bias in strength and characteristics, and improve productivity. It is an object of the present invention to provide a method of manufacturing a diaphragm for a speed reducer and a mold for manufacturing the same.

[Means for Solving the Problems]

A method for manufacturing a speaker diaphragm according to the present invention comprises laminating a film-shaped member containing at least one of a thermoplastic resin and a thermoplastic elastomer, and a woven cloth-shaped member containing high-elasticity fibers, and using the compression molding machine. After being held between the molding dies of the attached speaker diaphragm, these are preheated by a far infrared ceramic heater, etc., and then the outermost periphery of the mold is sealed to degas the inside of the mold under reduced pressure. Further, the film-shaped member and the woven material-like member are fluidized by heating the mold, and pressed by the mold to integrally mold, and subsequently, the mold is cooled to take out the molded member.

The mold used for manufacturing the speaker diaphragm is composed of a female mold and a male mold having a molding die surface for interposing a laminated sheet material and performing pressure molding in a conical shape. Is preferably provided with a through hole formed in the axial center portion and an annular hole formed in the mold in an annular shape and having an entrance and exit on the outer surface.

[Action]

As described above, a diaphragm for a speaker obtained by compression-molding a film-shaped member containing at least one of a thermoplastic resin and a thermoplastic elastomer and a woven cloth-shaped member containing a highly elastic fiber into an epoxy resin is an epoxy resin. The internal loss can be maintained at a value that is somewhat higher than when the resin is cured, and
Good vibration characteristics can be obtained without partial deviation in strength, which cannot be avoided in the case of injection molding. Further, when the prepreg is used, extra work such as storing it in a refrigerator in order to delay the progress of the curing reaction becomes unnecessary, which can contribute to the improvement of productivity.

Here, the characteristics can be changed if a thermoplastic elastomer is obtained by heating, melting, and kneading a reinforcing material such as highly elastic short fibers or whiskers.

Further, in manufacturing the speaker diaphragm, the workability is increased by preheating the laminate of the film state member and the woven material member with a far-infrared ceramic heater or the like. The productivity can be remarkably improved by adding the steps of heating and cooling the mold.

Then, a through hole is formed in the axial center portion of the mold to degas under reduced pressure,
By passing steam through the annular hole to heat the mold and passing water through it to cool the mold, the speaker diaphragm can be manufactured in an extremely short cycle.

〔Example〕

In the method for manufacturing a speaker diaphragm according to the present invention, as shown in FIG. 1 (a), a pan-based carbon fiber woven fabric 1 and a polyurethane elastomer film 2 are laminated and molded by a compression molding machine. After holding between the molds, Fig. 1 (b)
As shown in FIG. 1, these are preheated by the far infrared ceramic heater 3, and further, as shown in FIG. 1 (c), they are fluidized by heating the mold and are pressurized to be integrated.
In this case, preheating with the far-infrared ceramic heater 3 improves the workability and at the same time shortens the molding time for forming a mold. Further, the molding die includes a female die 10 and a male die 20 each having a molding die surface for interposing a laminated sheet material and performing pressure molding in a conical shape, and each has a through hole 11 formed in an axial center portion. ,twenty one
And annular holes 12 and 22 that are formed annularly inside the mold and have inlets and outlets on the outer surface.The inside of the mold is depressurized and degassed through the through holes 11 and 21, and steam is passed through the annular holes 12 and 22. The mold is made to flow to heat the mold, and water is made to flow to cool the mold. Then, after cooling the mold, the female mold 10 and the male mold 20 are separated and the molded product 4 is taken out and post-processed.

Note that steam or water is allowed to flow through the annular holes 12 and 22 via the switching valve 5.

2 (a), (b), and (c) are a cross-sectional view and a plan view showing the specific structure of the mold. In the figure, the female mold 10
Has a conical molding surface 13, and a through hole 11 is formed in the axial center portion thereof.
Five annular holes 12 are formed inside the molding die surface 13 respectively. Of these, the five annular holes 12 are successively communicated at two locations in the circumferential direction so that the fluid circulates, and
The innermost annular hole and the outermost annular hole are fluid introduction holes 14,
A fluid outlet 15 communicates with the peripheral side surface. The fluid introduction hole 14 and the fluid discharge hole 15 are connected to the switching valve 5 described above. Furthermore, bolt holes 16 for fixing the female die 10 to the molding machine with bolts are provided at four circumferentially outer circumferential positions of the annular hole 12, and the bolt holes 16 for fixing the female die 10 to the molding die 20 are aligned on a plane portion facing the male die 20. The bosses 17 are also provided at four equally divided positions in the circumferential direction. On the other hand, the male 20 is also similar to this,
It has a conical molding die surface 23, a through hole 21 is formed in the axial center portion thereof, and five annular holes 22 are formed along the molding die surface 23 therein. Among these, the five annular holes 22 are connected so that the fluid makes one round, and the innermost annular hole and the outermost annular hole are connected to the peripheral side surface by the fluid introduction hole 24 and the fluid outlet hole 25. The fluid introduction hole 24 and the fluid discharge hole 25 are connected to the switching valve 5 described above. Furthermore, an annular hole
Bolt holes 26 for fixing the male die 20 to the molding machine with bolts are provided at four circumferentially divided positions on the outer side of the 22, and a positioning hole for fitting with the boss 17 provided in the female die 10. 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 female die 20 when viewed from the molding die surface 23, and a ring 29 is circumferentially divided into eight equal parts in the base portion so that the product thickness can be easily changed. It is screwed in position.

FIG. 3 is a side view of the manufacturing apparatus of the speaker diaphragm. This device is mainly composed of a molding machine 30 in which a mold is mounted and pressure molding, a preheating device 40 for preheating the laminated sheet material stretched between the male and female molds 10 and 20, and an outer peripheral edge of the molded product. A press device 50 that removes burrs and unnecessary parts in the center by punching,
The storage device 60 stores the punched product.

Of these, the molding machine 30 has an upper platen 31 and a lower platen 32 that are integrated by columns, and these are also integrally fixed to a ram cylinder 34 that has a ram piston 33. It moves up and down through the lower platen 32 and generates a maximum compression force of 150 tons. A male mold is attached to the upper platen 31 via a mold mounting plate 35.
Twenty is attached. The upper mold mounting plate 35 has a groove 35a through which a tube connected to the through hole 21 of the male mold 20 is inserted. Further, a pressing ring 38 which is moved up and down by a small cylinder 37 is provided on the lower surface of the upper die mounting plate 35, and thereby the laminated sheet material is stretched. On the other hand, a surface plate is attached to the upper end of the ram piston 33, and the female die 10 is attached to the surface plate via a lower die attachment plate 39. The lower mold mounting plate 39 also has a groove 39a through which the pipe connected to the through hole 11 of the female mold 10 is inserted.
Is being worn.

Further, in the preheating device 40, a cylinder 41 is laterally fixed on a column, and a preheating plate 42 in which a ceramic heater is arranged is attached to a tip portion of a piston.When the cylinder 41 is operated, the preheating plate 42 is female. It is designed to extend to the upper surface of the mold 10.

The pressing device 50 is an upper platen that is integrated by the columns.
51 and a lower platen 52, of which the upper platen 51
A male punch 53 is attached to the lower platen 52 so as to be vertically movable by a hydraulic cylinder 54, and a female punch 55 is attached to the lower platen 52. Further, the press device 50 includes a vertical movement cylinder, and carries the pressure reduction and suction of the molded speaker diaphragm to move it from the mold position of the molding machine 30 to the female punch position, and the vertical movement cylinder. And a transfer part 57 for moving the punched product from the female punch position to a predetermined position of the storage table 61 of the storage device 60, and the transfer parts 56, 57 are integrally driven by the transfer arm 58. It is like this.

In the storage device 60, a plurality of rods 62, which are the center of stacking, are planted on a storage base 61.

The manufacturing process of the speaker diaphragm using the manufacturing apparatus configured as described above will be described for the case where a 20 cm caliber is first manufactured.

Baking carbon fiber woven cloth 1 Torayca CO63 manufactured by Toray Industries, Inc.
43 is used as a polyurethane elastomer film 2 and Unilon S-FO manufactured by Nippon Unipolymer Co., Ltd. is laminated. This gives 50% by weight of carbon fiber and 50% of polyurethane.
A weight percent of laminated film member is obtained. The laminated film member is placed on the female mold 10 of the molding machine 30 with the centers thereof aligned, and then the cylinder 37 arranged on the upper platen 31 is operated to lower the pressing ring 38, thereby forming the laminated film member. The outer edge of the is pressed down with a pressure of about 5 to 30 kg / cm ² .

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 portion of the laminated film member, and after preheating the laminated film member to 120 to 160 ° C., the preheating plate 42 is illustrated. Return to the original position.

On the other hand, at the same time when the pressing ring 38 starts to descend, the switching valve 5 attached to the molding machine 30 is actuated, and the female die 10 and the male die 10 are
The female mold 10 and the male mold 20 are heated to 180 ± 5 ° C. by passing steam through the annular holes 12 and 22 of 20.

Next, pressure oil is passed through the ram cylinder 34 of the molding machine 30 to raise the ram piston 33. With this rise, the laminated film member is pushed by the male die 20 in order from the center part, and the female die
Fits between 10 and 20 male types. At this time, by pressing the entire outer edge portion of the laminated film member with the pressing ring 38, it is possible to prevent partial overlap that tends to occur during deformation and to perform uniform narrowing.

Next, raise the ram piston 33 and place 60 to 100 kg / cm ^{2 on the} parting part of the mold (corresponding to the ring 29 in Fig. 2).
The pressure is generated to impregnate the urethane resin between the carbon resins. This makes the inside of the mold airtight. Therefore, through the through hole 11 of the female die 10 and the through hole 21 of the male die 20, the gas inside the die is sucked by a vacuum pump (not shown) to maintain a reduced pressure state (755 mmHg or less).

Next, stronger pressure (90 to 140 kg / cm ² ) is applied to the entire mold to flow the matrix and impregnate the carbon fibers. Then, the switching valve 5 is switched to pass the cooling water before the entire amount of the matrix flows out. Then, as the mold temperature decreases, the shearing force of the matrix increases and eventually the flow stops.

Next, when the temperature of the matrix becomes 40 ° C. or less and the shaped and solidified, the valve of the cooling water is closed to stop the cooling. At the same time, a valve (not shown) directly connected to the vacuum pump is switched to directly connect to the atmosphere.

Then, at the same time as removing the oil from the ram cylinder 34 of the molding machine 30, the valve directly connected to the through hole 21 of the male mold 20 was switched to the inside of the mold.
Introduce compressed air of 5kg / cm ² . This ensures that the molded product is attached to the female mold 10 when the molding die is opened.

Next, the ram piston 33 is lowered to a predetermined position. Simultaneously with the end of this descent, the valve directly connected to the through hole 21 of the male die 20 is switched to send compressed air of 5 kg / cm ² . As a result, the molded product leaves the molding surface 23 of the male mold 20.

Next, the transfer arm 58 attached to the press device 50 moves the transfer section 56 to the center position of the upper part of the molded product. Therefore,
The cylinder of this transfer unit 56 is lowered and sucked at the suction port,
Subsequently, the cylinder is raised to separate the molded product from the male mold 20.

Then, the transfer arm 58 moves the transfer section 56 to the center position of the female punch 55 of the pressing device 50. Then, the cylinder of the transfer section 56 is lowered to release the suction by reducing the pressure of the suction port, the molded product is dropped onto the female punch 55 of the press device 50, and then the suction port of the transfer section 56 is changed. To raise. When the molded product is dropped onto the female punch 55, the protrusions of the molded product fit into the female punch 55 and the centers are aligned.

Next, the transfer arm 58 moves the transfer unit 56 to an intermediate position between the molding machine 30 and the pressing device 50, and stops there.

Next, the male punch 53 is lowered by the hydraulic cylinder 54 of the pressing device 50, the center hole portion of the molded product and the peripheral burr portion are punched out, and then the male punch 53 is raised.

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

Further, as the transfer arm 58 moves and stops, the transfer section 57 moves to the upper part of the female punch 55 of the press device 50, so that the cylinder of this transfer section 57 is lowered and the flat portion of the outer edge is moved to 4 mm.
Adsorb with one suction port. Subsequently, the cylinder is raised to separate the molded punch from the female punch 55.

Next, since the transport unit 57 moves to the center position of the stock pin of the storage device 60 along with the operation of the transport unit 56 to move the next molded product, at this time, the cylinder of the transport unit 57 is lowered to absorb the suction. Release the negative pressure to raise the cylinder. As a result, the punched molded products are dropped and stacked.

Next, as described above, the transfer arm 58 is moved to and stopped at the position where the transfer section 56 is located between the molding machine 30 and the pressing device 50.

A time chart showing these relationships is as shown in FIG.

The above is a speaker with a diameter of 20 cm, which is obtained by laminating one pan-based carbon fiber woven cloth (Torayca C06343 manufactured by Toray Industries, Inc.) and one polyurethane elastomer film (Unilon S-FO manufactured by Nippon Unipolymer Co., Ltd.). It is a manufacturing process of the diaphragm for use, but by changing the laminated film member, for example, two pieces of bread-based carbon fiber woven cloth (Torayca trading card C06151B)
In addition, a polyurethane elastomer film (Resamine P-1078CL made by Dainichiseika Co., Ltd.) and aramid short fibers (Kevra 49 fiber chop length 9mm made by Toray-Jupon Co., Ltd., 9 mm length) are heated and kneaded using a roll, and aramid short fibers Crush,
It is also possible to use a material obtained by fibrillating, uniformly dispersing in polyurethane, sandwiching the film-formed product, and laminating it. In this case, the carbon fiber content is 50% by weight, the polyurethane content is 40% by weight, and the aramid short fiber content is 10% by weight.

Further, a diaphragm for a speaker having a diameter of 30 cm was manufactured by the above mold, device and method. In this case, one piece of bread-based carbon fiber woven cloth (Toray Industries, Inc., trading card C06151B) and one piece of polyurethane elastomer film (Japan Unipolymer Co., Ltd., Unilon S-FO) are used as materials.
And a piece of speaker cone paper (30
Cone paper for cm (15 g) is used as a laminate to make 25% by weight of carbon fiber woven cloth, 25% by weight of polyurethane and 50% by weight of cone paper.

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

The frequency characteristic of the diaphragm having a diameter of 20 cm is as shown in FIG. 5, and the frequency characteristic of the diaphragm having a diameter of 30 cm is as shown in FIG.

As is clear from these tables and characteristic diagrams, the internal loss (tan δ) of this example is significantly improved as compared with the conventional product. That is, as the frequency characteristic of the speaker diaphragm, the peak of the primary resonance point in the high frequency range is suppressed to be low, the characteristic becomes smooth, and the second harmonic distortion is also reduced. .

Further, in the molding of conventional products, since a thermosetting resin was used for the matrix, a cycle of 10 to 15 minutes was required, but in this example, it is possible to mold in about 30 seconds cycle, so the productivity is greatly improved. Can be made.

〔The invention's effect〕

As is clear from the above description, according to the method for manufacturing a speaker diaphragm of the present invention, a film-shaped member containing at least one of a thermoplastic resin and a thermoplastic elastomer, and a woven cloth-shaped member containing a highly elastic fiber. Since and are integrated by compression molding, the internal loss can be maintained at a value that is somewhat higher than when the epoxy resin is cured, and there is no partial bias in strength that was unavoidable in the case of injection molding. Good vibration characteristics can be obtained. Further, when the prepreg is used, it is not necessary to store it in the refrigerator in order to delay the progress of the curing reaction.

In this case, the characteristics can be further improved by using a thermoplastic elastomer obtained by heating, melting and kneading a high elastic fiber or a reinforcing material such as whiskers.

Further, in the method for manufacturing the speaker diaphragm according to the present invention, the workability is increased by preheating the laminate of the film-state member and the woven material-like member with a far infrared ceramic heater, etc. Since the gas process and the process of heating and cooling the mold are added, the productivity can be greatly improved.

Further, the mold according to the present invention has a structure in which a through hole is formed in the shaft center portion to perform degassing under reduced pressure, steam is passed through the annular hole to heat the mold, and water is passed to cool the mold. Therefore, the speaker diaphragm can be manufactured in an extremely short cycle.

[Brief description of drawings]

1 (a), (b), and (c) are explanatory views for explaining a schematic configuration of a speaker diaphragm made according to the present invention,
2 (a), 2 (b) and 2 (c) are a sectional view and a plan view showing the configuration of an embodiment of the speaker plate diaphragm manufacturing die of the present invention, and FIG. 3 is the speaker diaphragm manufacturing process. FIG. 4 is a side view of the device, FIG. 4 is a time chart showing the manufacturing process by this manufacturing device, and FIGS. 5 and 6 are frequency characteristic diagrams of the speaker diaphragm according to the present invention. 1 ... Bread-based carbon fiber woven fabric, 2 ... Polyurethane elastomer film, 3 ... Far infrared ceramic heater, 10
...... Female mold, 11,21 …… Through hole, 12,22 …… Annular hole, 20 …… Male mold, 30 …… Molding machine, 40 …… Preheating device, 50 …… Press device, 60 …… Storage device .

Continuation of the front page (56) References JP-A-62-263798 (JP, A) JP-A-57-33893 (JP, A) Practical application Sho-63-52384 (JP, U)

Claims (2)

[Claims] 1. A speaker diaphragm mounted on a compression molding machine, comprising laminating a film-shaped member containing at least one of a thermoplastic resin and a thermoplastic elastomer and a woven cloth-shaped member containing high-elasticity fibers, and mounting the speaker diaphragm on a compression molding machine. The film-shaped member and the woven cloth-shaped member laminated and held between the molds are preheated, the outermost peripheral portion of the mold is sealed and the inside of the mold is deaerated under reduced pressure, and the mold is heated. A method of manufacturing a speaker diaphragm for fluidizing the film-shaped member and the woven material-like member, integrally molding by pressing the mold, and cooling the mold to take out the molded member. 2. A laminate comprising a female die and a male die having a molding die surface for pressure-forming a conical shape with a laminated sheet material interposed therebetween. These female die and male die are respectively formed in the axial center portion. A hole and an annular hole that is formed in an annular shape inside the mold and has an inlet / outlet port on the outer surface, is decompressed and degassed inside the mold through the through hole, and steam is passed through the annular hole to heat the mold, A mold for manufacturing a diaphragm for a speaker, which has a structure capable of cooling water by flowing water.