JP2005323022A - Method for manufacturing diaphragm for electroacoustic transducer, and diaphragm for the electroacoustic transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a diaphragm for an electroacoustic transducer which can easily have a uniform coating formed in superior in appearance on its top surface and also have the coating formed as well, even when a mixture is mixed with a paint to obtain desired properties, and the diaphragm for the electroacoustic transducer which is manufactured by the same. <P>SOLUTION: A specified amount of a liquid body, as a material different from a diaphragm material, is rotated on an axis perpendicular to the center of the diaphragm shape, while the rotating speed is controlled to feed a specified amount of the liquid body to the center part of the diaphragm which is held horizontally or an arbitrary position outside the center part of the diaphragm; and the liquid body is spread with a centrifugal force, to coat the front and/or back surface of the diaphragm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a diaphragm for an electroacoustic transducer such as a speaker or a microphone, which is a kind of acoustic equipment, and a diaphragm for an electroacoustic transducer manufactured thereby.

  The surface of the speaker diaphragm may be painted for the purpose of adding functions such as design and physical properties.

  As a means for painting in general, there are brush painting and spray painting as shown in Japanese Patent Publication No. 7-87636.

  In brush coating, it is difficult to control the coating thickness, and there is a problem that the surface finish becomes dirty because the surface is rubbed with a brush.

  On the other hand, spray coating is relatively clean and the coating thickness is uniform, but high-viscosity paints are difficult due to the high pressure required, and the coating gun clogs when a mixture is added to the paint. There is a drawback.

  Moreover, it is common to add a filler (filler) to the paint for improving various functions. In order to further improve the function of the speaker diaphragm over the paint, it is conceivable to add various fillers. For example, pearl mica, titanium oxide, calcium carbonate or the like is added to improve design properties, or mica or glass fiber is added to improve physical properties.

  The shape of these fillers generally includes fibrous, needle-like, plate-like, spherical and the like, and the size varies from nanometer level to millimeter level depending on the application and function.

In addition, when fibrous materials such as glass, carbon, aramid, and PBO (parabenzoxazaol) are mixed as fillers, it is well known that the physical properties differ depending on the directionality (orientation) of the fibers in the coating film. . When coating is performed for the purpose of improving the physical properties of the diaphragm, it is easily conceivable to reinforce by combining fibers in order to obtain a greater effect.
Japanese Patent Publication No. 7-87636

  However, when a paint mixed with fibers is applied to the diaphragm by brush coating, the brush scratches the fibers and cannot be uniformly distributed. If the diaphragm is coated by spray coating, the coating gun is clogged and cannot be painted.

  Therefore, it has been extremely difficult to paint a paint containing fibers.

  The present invention has been proposed in view of the above, and the object is to form a coating film that is easily uniform and has a good appearance on the surface, and a mixture is mixed in a liquid material. Even so, an object of the present invention is to provide a method for producing a diaphragm for an electroacoustic transducer capable of forming a coating film and obtaining desired physical properties, and a diaphragm for an electroacoustic transducer produced thereby.

  The invention according to claim 1 is a vibration in which a predetermined amount of liquid material made of a material different from the diaphragm material is rotated around an axis perpendicular to the center of the diaphragm shape, and rotated horizontally, and held horizontally. A predetermined amount is charged at the center of the plate or an arbitrary position outside the center of the diaphragm, and the liquid material is spread by centrifugal force to be applied to the front and / or back of the diaphragm to achieve the above object. ing.

  The invention according to claim 2 is the object according to claim 1, wherein the liquid material is a paint, and at least one fibrous material of organic fiber, inorganic fiber and whisker is mixed with the liquid material. Has achieved.

  According to a third aspect of the present invention, in the second aspect, the centrifugal force can be adjusted by controlling the rotational speed, and the fibrous material is oriented radially or circumferentially on the front surface and / or the rear surface of the diaphragm. Has achieved the above objectives.

  The invention according to claim 4 is a diaphragm for an electroacoustic transducer manufactured by any one of the above methods.

  According to the first aspect of the present invention, by rotating the diaphragm main body 1 while controlling the number of rotations, the liquid material dripped at the center thereof is expanded to the outer peripheral side by centrifugal force, and on the surface of the diaphragm main body. Since the coating film 6 is formed, the coating film 6 having a substantially uniform coating thickness can be easily obtained. In this case, a desired coating thickness can be easily obtained by managing and controlling the rotation speed.

  In addition, as described in claim 2, even if a filler is mixed, a substantially uniform coating film 6 can be formed, and desired physical properties can be obtained.

  Further, according to the third aspect, since the centrifugal force can be adjusted by controlling the rotational speed, the force for pushing the fiber to the outer periphery of the rotation can be controlled by changing the centrifugal force, and the fiber orientation The distribution can be arbitrarily controlled, and the orientation can be oriented radially or circumferentially from a disordered state by changing the rotation speed.

  As a result, it is possible to obtain a diaphragm for an electroacoustic transducer having a substantially uniform coating thickness, good appearance, and desired physical properties.

  FIG. 1 shows a side cross-section of a cone-shaped paper diaphragm main body. The diaphragm main body 1 is manufactured through processes such as papermaking, drying, and heat pressing of pulp, and includes a bottomed neck portion 3 having a bottom portion 2, a conical body 4, a flange-shaped outer peripheral portion 5 and the like. ing.

  The present invention is characterized in that a coating film 6 having a substantially uniform thickness is easily formed on, for example, the front surface of the diaphragm main body 1.

  That is, FIG. 2 (a)-(g) shows an example of the coating-film formation process by this invention.

  In FIG. 2 (a), reference numeral 7 denotes a base mold provided with a concave diaphragm body set portion 8 having a shape substantially corresponding to the diaphragm body 1, and this base mold 7 has an appropriate configuration including a motor. It is connected to a rotating device (not shown) and can rotate at a desired rotational speed clockwise or counterclockwise about an axis perpendicular to the center of the diaphragm body 1.

  In forming the coating film 6, first, the diaphragm main body 1 is set horizontally on the base mold 7 as shown in FIG.

  Next, as shown in FIG. 2C, the base mold 7 is rotated in an appropriate direction by driving a rotating device (not shown). The rotational speed of the base mold 7 can be adjusted to an arbitrary rotational speed by controlling the energization of the motor of the rotating device, for example.

  Next, as shown in FIG. 2D, the liquid paint 10 is dropped through the nozzle 9 for dropping the paint. A predetermined amount of the coating material 10 is dropped and charged at an almost central portion of the diaphragm or an arbitrary position outside the central portion.

  The coating material 10 is continuously dropped by a predetermined amount. After the predetermined amount is dropped, the paint dripping is stopped. Since the base mold 7 is rotating, as shown in FIG. 2 (e), the dropped paint 10 spreads toward the outer peripheral side of the body 4 of the diaphragm main body 1 by centrifugal force.

  Then, as shown in FIG. 1 (f), the excess paint scatters outward by centrifugal force. The upper surface 7a of the outer periphery of the diaphragm body set portion 8 of the base mold 7 is substantially horizontal so as not to prevent the paint 10 from spreading in the outer peripheral direction.

  The upper surface 7a may be a tapered surface that is inclined downward toward the outside.

  FIG. 2G shows a state where the diaphragm main body 1 is removed from the base mold 7 and dried.

  In addition, in order to obtain a desired physical property value, the paint 10 may be a mixture of organic fiber, inorganic fiber, and whisker mixed with a filler composed of at least one fibrous material.

  In this case, the rotational speed can be increased or decreased, and the fibrous material 11 can be oriented radially as shown in FIG. 3 or radially as shown in FIG. 4 by the strength of centrifugal force. it can.

  Thus, by changing the orientation of the fibrous material 11, the physical properties of the diaphragm can be changed, and the frequency characteristics and audibility of the speaker can be changed.

  In addition, what is necessary is just to punch through the bottom part of the neck part 3 as shown in FIG.

  Hereinafter, preferred embodiments of the present invention will be described.

  A predetermined amount of an emulsion paint mainly composed of vinyl acetate having a viscosity of 2200 mPa · S and a solid content of 50% is dropped on the center of a pulp cone body having a diameter of approximately 13 cm and a thickness of 0.41 mm, and is rotated for 5 seconds at a rotation speed of 600 rpm. A uniform coating film was obtained on the surface of the diaphragm. This diaphragm was left for 1 hour in a 60 ° C. atmosphere to completely evaporate the solvent component to obtain a coated cone.

  FIG. 6 shows frequency characteristics in the first embodiment.

  The emulsion paint of Example 1 was blended with 1% carbon fiber having an elastic modulus of 215 GPa and a fiber length of 3 mm and dispersed uniformly to obtain a fiber blend paint. When this was rotated at 600 rpm for 5 seconds in the same manner as in Example 1 and coated on the surface of the diaphragm, the blended fibers were oriented in the circumferential direction.

  In the same manner as in Example 1, the rotating speed was rotated at 1280 rpm for 5 seconds, and a coating cone was obtained by the same treatment.

  When it was rotated at 1280 rpm for 5 seconds in the same manner as in Example 3, the blended fibers were oriented in the radial direction (radial direction) with respect to the circumference.

  Samples were cut into strips having a width of 5 mm × 60 mm in the diameter direction of the diaphragms obtained in Examples 1 to 4, and measured by the vibration lead method. The physical property values are shown in Table 1.

  In the above embodiment, the case where the neck portion 3 of the diaphragm main body 1 has a bottomed shape has been described in forming the coating film 6. However, it is of course possible to use a plate having no bottom portion 2 and having a hole formed in advance. It is.

  Further, the diaphragm main body 1 is not limited to a single layer structure but may be a multilayer structure having two or more layers.

  Furthermore, the diaphragm main body 1 is not limited to paper, but may be made of resin, for example.

  Furthermore, the coating film 6 may be formed on the back surface or only the back surface as necessary, in addition to the front surface of the body 4 portion of the diaphragm main body 1.

  When the coating film 6 is formed on the back surface, for example, a rotatable base mold 7A as shown in FIG. The base mold 7A is provided with a convex diaphragm set portion 8A having a conical shape corresponding to the shape of the diaphragm main body.

  The diaphragm body 1 is set on the diaphragm body setting portion 8A as shown in FIG. 7B, and the paint 10 is dropped from the nozzle 9 as shown in FIG. 7C while rotating the base mold 7A. You can do it.

  Other configurations are the same as those in the above-described embodiment.

  Further, the diaphragm main body 1 is not limited to a cone shape, and for example, a rotatable base mold 7B as shown in FIG. 8A is used, and a coating material 10 is applied to a flat diaphragm main body 1 ′ via a nozzle 9. It is also possible to drop and form a coating film on the surface.

The sectional side view of an example of the diaphragm main body of this invention is shown. (A)-(g) shows the process explanatory drawing of this invention. Explanatory drawing which shows the state in which the fibrous material was orientated in the radial direction in the diaphragm of this invention. Explanatory drawing which shows the state with which the fibrous material was orientated in the circumferential direction. The sectional side view of the produced diaphragm of the present invention. The frequency characteristic figure of Example 1 of this invention is shown. (A)-(c) shows explanatory drawing of the coating-film formation process to a diaphragm back surface. (A)-(b) shows explanatory drawing of the coating-film formation process to a flat vibration plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diaphragm main body 2 Bottom part 3 Neck part 4 Body 5 Outer peripheral part 6 Coating film 7, 7A, 7B Base type | mold 8, 8A Diaphragm main body set part 9 Nozzle 10 Paint 11 Fibrous material

Claims (4)

  A predetermined amount of liquid material of a material different from that of the diaphragm material is rotated around an axis perpendicular to the center of the diaphragm shape by controlling the rotation speed, and the center part of the diaphragm or the diaphragm A method for manufacturing a diaphragm for an electroacoustic transducer, wherein a predetermined amount is charged at an arbitrary position outside a center portion, the liquid material is expanded by centrifugal force, and is coated on the front and / or back of the diaphragm.   The diaphragm for an electroacoustic transducer according to claim 1, wherein the liquid material is made of a paint, and at least one fibrous material of organic fiber, inorganic fiber, and whisker is mixed with the liquid material. Production method.   3. The electroacoustic conversion according to claim 2, wherein the centrifugal force can be adjusted by controlling the rotational speed, and the fibrous material is oriented radially or circumferentially on the front surface and / or the back surface of the diaphragm. A method for manufacturing a mechanical diaphragm.   The diaphragm for electroacoustic transducers produced by the method according to any one of claims 1 to 3.

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