JP2000354294A - Loudspeaker and manufacture of the loudspeaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a loudspeaker by which the response of the loudspeaker can be enhanced without especially changing material of a cone and to provide the loudspeaker manufactured by this manufacturing method. SOLUTION: A circular-arc side of arc ribs 4A-4D whose one side is formed nearly to be a circular-arc is opposed to a curved plate (plate) 2, after fixing ends of the ribs 4A-4D to the curved plate 2, the circular-arc side of the ribs 4A-4D is fixed to the curved plate 2 while curving the curved plate 2 to form a diaphragm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a speaker and a speaker manufactured by the method.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional example of a cone type speaker, wherein reference numeral A denotes a frame, B denotes an edge, C denotes a damper, D denotes a cone (diaphragm), E denotes a voice coil, and F denotes a voice coil.
Is a permanent magnet, G is a pole, and H is a damper. In the speaker, by supplying an electric signal to the voice coil E, the energy of the electric signal is converted into kinetic energy of the cone D. Also, the ultimate goal of a speaker is to convert all of the input signals into kinetic energy, and ideally, it is required to be infinitely rigid and infinitely light. It is naturally impossible to fill, and from the viewpoint of cost, a structure in which pulp is made into a predetermined cone shape,
Alternatively, a sheet-shaped pulp is generally formed into a predetermined cone shape by heating and deforming the pulp into a plastic state.

[0003]

By the way, in order to convert all the electric energy supplied to the voice coil E into kinetic energy, the motion of the voice coil E is transmitted to the cone D as it is, that is, the cone D Ideally, the mechanical characteristics of the voice coil E should be good. However, there are various factors that deteriorate the response of a cone used as a diaphragm in a conventional speaker.

[0004] That is, if the cause of the response drop is estimated, (1) When a sudden large current flows through the voice coil E,
A large acceleration will occur in the cone D. In this case, the cone D first deforms as shown by a chain line in FIG. 5, and then returns to the original shape while responding to the movement of the voice coil E. And behave in the same direction. Therefore, due to the above deformation, a time delay occurs in the transfer of the motion from the voice coil E to the cone D, or a part of the kinetic energy of the voice coil E is
Is consumed as heat energy by the deformation of
Insufficient kinetic energy is transmitted to the air, which causes a decrease in response.

(2) The paper pulp is normally in a porous state (having a high porosity) because the fibers are intricately entangled and directed in various directions. By the interference of vibrations diffused in a direction different from the direction of movement of the coil E, or by the voice coil E
Movement in the axial direction of tends to increase the density of the material inside the cone D (to reduce the gap between the fibers) and absorb kinetic energy.

[0006] In order to eliminate some of the above-mentioned factors of the response decrease, for example, plastics, metals,
Alternatively, the density of the pulp is increased by mixing materials such as carbon fiber. However, if these materials are mixed, the weight per unit area of the cone D increases and the efficiency (a predetermined current is applied to the voice coil E). the sound pressure is measured at a position at a predetermined distance of the speaker front) is decreased when the flow, or the lowest resonance frequency f ₀ is a problem of decrease. The decrease in f ₀ is not necessarily a disadvantage because the reproduction frequency of the low-pitched loudspeaker is low, but it is not a favorable tendency because the low-pitched loudspeaker is a factor that impairs the reproduction performance of the middle and high treble range. .

[0007] The present invention has been proposed in view of the above circumstances, and a speaker manufacturing method capable of improving the response of a speaker without making a special change to the material of the cone, and a speaker manufactured by the method. The purpose is to provide.

[0008]

In order to achieve the above object, a speaker manufacturing method according to the present invention is characterized in that a stress is applied to a diaphragm. For example, the diaphragm is formed into a curved surface by elastically bending and deforming the plate body, and the surface on the compression deformation side of the diaphragm is attached to the front.

With the above structure, the stress applied to the diaphragm increases the density of the surface that directly imparts kinetic energy to the air, and generates a unidirectional stress in the tissue constituting the cone. Vibration that has propagated in a random direction is propagated in the direction of the stress with a certain direction. Specifically, the following manufacturing method is employed.

The arc side of the chordal rib having one side formed in a substantially arc shape is opposed to the plate, and first, the end of the rib is fixed to the plate. Then, while bending the plate body,
The rib is fixed to the plate. Usually, a plurality of ribs are fixed. By fixing in this manner, stress can be applied to the plate body.

A vertical beam may be fixed to both sides of the plate in advance. This allows the plate to be curved and fixed to the ribs while holding both sides of the plate in a straight line. If the plate is made of wood and its fibers are fixed in the longitudinal direction of the rib, a greater internal stress can be applied.

Further, after fixing the rib and the plate body,
A paint may be applied to one side of the plate body thicker than the other side. The paint shrinks when it dries, but if the thickness of the paint is varied in this way, stress can be applied to the plate due to the difference in shrinkage force. Note that the paint may not be applied to one side surface. Further, the present invention can be applied to not only a plate body to which the rib is fixed but also a diaphragm of any speaker.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, one embodiment of a speaker manufactured by the speaker manufacturing method of the present invention will be described. In FIG. 1, what is indicated by reference numeral 1 is a diaphragm. As shown in FIG. 2, the diaphragm 1 has a curved plate (plate body) 2.
And flat plates (longitudinal beams) 3 provided on both sides thereof, respectively.
It is composed of The curved plate 2 is curved so that both side portions substantially form a part of a cylindrical (coasted cylinder) surface,
The central part is almost planar. The flat plate 3
Are part of a plane substantially parallel to the axis of the curved plate 2, and are fixed to both side edges of the curved plate 2.

The curved plate 2 has both ends and an intermediate portion having a plane shape substantially equal to a cross-sectional shape orthogonal to the axis of the curved plate 2, and one side of the curved plate 2 is formed in a substantially arc shape. Horizontal ribs (chordal ribs) 4A to 4D are fixed. Between these horizontal ribs 4A to 4D, vertical ribs 5A to 5F directed in a direction perpendicular to the horizontal ribs are provided to connect the horizontal ribs 4A to 4D to each other at respective portions. 5F is also fixed to the surface of the curved plate 2. Further, between the vertical ribs 5A and 5B and the curved plate 2, between the vertical ribs 5C and 5D and the curved plate 2, and between the vertical ribs 5E and 5E.
Between the F and the curved plate 2, the transverse ribs 6 </ b> A, 6 </ b> B having a planar shape corresponding to the cross-sectional shape of the curved plate 2 at a corresponding portion.
6C and 6D and 6E and 6F are fixed respectively,
As a whole, they form a lattice.

The curved plate, the flat plate, and the vertical and horizontal ribs are desirably lightweight and have high rigidity. In this embodiment, a balsa material is used. In addition, all of these members are cut and combined so that the direction of the fiber is directed to the longitudinal direction of the member. Further, in this embodiment, the curved plate 2 is formed into the shape shown in the figure by elastically deforming a flat plate as described later, and this elastically deformed state (state in which internal stress is generated) is maintained. The structure in which each rib is fixed to the curved plate 2 is adopted. As the means for fixing the rib, any of an adhesive and a mechanical means such as a bolt and a nut can be applied.

As shown in FIG. 2, the diaphragm 1 having the above-described structure is arranged inside a frame member 7 having a frame shape. Edge members 8 are provided between the horizontal ribs 4A and 4D and the inner periphery of the frame member 7 to prevent air from flowing therebetween. For example, a material having high elasticity and good vibration damping properties, such as urethane foam resin, is applied to seal the space between the diaphragm 1 and the frame member 7.

Further, six drive units 9 are connected to the diaphragm 1. Three drive units 9 are arranged on the back surface of both flat plates 3, respectively, and supply an electric signal of a voice coil (moving coil) 10 to act between the voice coil 10 and the magnet 11. It functions as driving means for driving the vibration plate 1 by the electromagnetic force generated. The magnet 11 is fixed to an inner surface of a back plate 12 provided on a back surface of the frame member 7. Further, the voice coil 10 is connected to a frame 13 integral with the magnet 11 via a damper 14 which can be elastically deformed. Further, an opening 12a is provided in the back plate 12 to open a space on the back side of the diaphragm 1 so that this space does not become a closed chamber (a space where air is compressed and back pressure is generated). ing.

Further, the reference numeral 15 in the figure denotes a curved plate 2 and a flat plate 3 near the connecting portion of each drive unit 9.
A reinforcement member for reinforcing the connection portion from the front side, and a reinforcement member indicated by reference numeral 16 is a reinforcement member for reinforcing the same from the back side, reference numeral 17.
Is an opening for providing an auxiliary small speaker (not shown) for, for example, treble. When the small speaker is not used, the opening 17 may be omitted.

Next, a method of bonding the curved plate 2 and the horizontal ribs 4A to 4D will be described with reference to FIGS. First, as shown in FIG. 3A, the flat plate 3 is fixed to both ends of the curved plate 2. The curved plate 2
The fiber direction is located in the left-right direction. next,
The horizontal ribs 4A to 4D are arranged at predetermined intervals in the vertical direction (in the drawing, in the depth direction of the drawing), with their arc sides facing the curved plate 2 and their ends fixed to the ends of the curved plate 2. Then, as shown in FIG. 3B, the curved plate 2 and the horizontal ribs 4 </ b> A to 4 </ b> D adhere to each other while bending the curved plate 2,
Stick. Here, when the curved plate 2 is curved, the flat plate 3 holds both side surfaces in a straight line, and the horizontal ribs 4A to 4D.
And the curved plate 2 are securely fixed.

By fixing the curved plate 2 and the lateral ribs 4A to 4D in this manner, the elastically deformed state of the curved plate 2 (state in which internal stress is generated) is maintained. Since the fiber direction of the curved plate 2 is the left-right direction (the rib longitudinal direction), internal stress is effectively generated. After that, the surface of the curved plate 2 is coated with a varnish. At this time, the coating is performed by changing the coating film thickness on the front and back surfaces of the curved plate 2. Painted varnish shrinks when drying, but the thicker the paint, the more shrinkage,
Further internal stress can be applied to the curved plate 2.

In the planar speaker configured as described above, the energy of the electric signal is converted into mechanical energy as reciprocating motion of the voice coil 10 (reciprocating motion in a direction perpendicular to the plane plate 3) by the drive unit 9. Then, the curved plate 2 of the diaphragm 1 is vibrated to generate a musical sound. Further, inside the curved plate 2, as shown, the front surface of the curved plate 2 and the lateral ribs 4A to 4D, 6A to
Since a space surrounded by the space 6F and the vertical ribs 5A to 5F is formed, the air held in this space is pushed forward of the diaphragm 1.

Further, since the diaphragm 1 is in a state of having an internal stress due to elastic deformation, a compressive stress is generated on an inner surface thereof (a surface facing forward), and the tissue becomes dense, and the tissue between the tissues becomes dense. Small deformation such as narrowing the gap is reduced, and the motion of the voice coil 10 can be reproduced as it is, and the vibration can be performed with the minimum attenuation. Furthermore, the direction of propagation of the vibration in the fiber of the wood constituting the diaphragm 1 is generated, and the loss due to the interference of the vibration propagating in a random direction is suppressed. In addition, since the diaphragm 1 has a curved surface with one axis as the center, the left and right sides in FIG. Good directional characteristics can be obtained in the direction. Therefore, when performing two-channel stereo reproduction, good stereo reproduction performance can be exhibited by arranging the planar speakers oriented in the direction shown in FIG. 1 in the left-right direction in FIG.

FIGS. 4 and 5 show examples in which the present invention is applied to a cone type speaker. That is, as described in the related art, the conventional cone is formed by squeezing a pulp dissolved in water into a predetermined cone-shaped net, or by deforming the pulp into a plastic state by heating. Although no internal stress is caused by the deformation, in this embodiment, a fan-shaped sheet as shown in FIG. 5 (a pulp, a wood, a plastic, or a composite material thereof is conceivable as a material). By elastically deforming the sheet 20 into a cone shape as shown in FIG. 4, by forming the sheet 20 by joining the edges 20a and 20b of the sheet 20 in a state where they face each other in a radial direction, internal stress is generated. I have to.

Also in such a cone-shaped diaphragm, an improvement in response can be expected by setting the internal stress state as in the case of the first embodiment. Further, the surface of the sheet 20 is coated with a varnish. At this time, the coating is performed by changing the coating film thickness on the front and back surfaces of the sheet 20. The coated varnish shrinks when it dries, but the thicker the varnish shrinks, the greater the shrinkage.
0 can be further stressed internally.

As shown by the dashed line in FIG.
A tape-like reinforcing material 22 is provided on the front, back, or both of the seams 21 to cover the seam 21 in place of the structure in which the 20b is abutted and adhered.
To the edge 2
0a and 20b may be combined. Alternatively, the edges 20a and 20b may be connected to each other in a partially overlapped state. The front and back surfaces of the cone formed by plastic deformation may be coated with a varnish. At this time, an internal stress can be applied to the cone by applying different coating film thicknesses on the front and back surfaces of the cone.

[0026]

As is apparent from the above description, according to the present invention, the density of the diaphragm or the rigidity of the speaker is increased by using the same material, that is, without mixing other materials. Because of this, it is possible to improve the mechanical response to the input signal and reproduce the musical sound faithfully without lowering the efficiency and lowering the minimum resonance frequency by mixing other materials. Play.

[Brief description of the drawings]

FIG. 1 is a perspective view of a diaphragm used for a speaker shown as one embodiment of the present invention.

FIG. 2 is a sectional view of the speaker.

FIG. 3 is a view showing a manufacturing process of the speaker diaphragm.

FIG. 4 is a perspective view of a speaker diaphragm according to another embodiment of the present invention.

FIG. 5 is a development view of the diaphragm.

FIG. 6 is a sectional view showing a conventional speaker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration board 2 Curved board 3 Flat board 4A-4D Horizontal rib (chordal rib)

Claims (5)

[Claims] 1. A chordal rib having one side formed substantially in an arc shape, the arc side of which is opposed to a plate, and an end of the rib is fixed to the plate, and then the plate is bent. A method of manufacturing a speaker, comprising: forming a diaphragm by fixing an arc side of the rib to a plate. 2. The method for manufacturing a speaker according to claim 1, wherein the ribs are fixed after fixing the vertical beams on both sides of the plate. 3. The method of manufacturing a speaker according to claim 1, wherein the plate is made of wood, and fibers of the plate are fixed in a longitudinal direction of the rib. 4. The speaker manufacturing method according to claim 1, wherein after fixing the rib and the plate, one side surface of the plate is
A method for manufacturing a speaker, comprising applying a paint thicker than other sides. 5. A speaker according to claim 1, wherein one side of the diaphragm of the speaker is coated with a thicker paint than the other side.