JPH01241300A - Speaker diaphragm - Google Patents

Abstract

PURPOSE:To improve sound pressure frequency characteristic while suppressing split resonance and to improve the yield of manufacture by using radial direction threads and circumferential direction threads so as to weave the diaphragm stereoscopically into the shape of a speaker and employing a curved face stereoscopic textile solidified by a matrix member. CONSTITUTION:In case of forming a curved conical honey-comb speaker diaphragm, radial direction threads 1 prolonged in the radial direction from the center and circumferential threads 2 in a direction substantially orthogonal to the radial direction threads 1 are woven together to form a stereoscopical textile. In this case, the curved shape stereoscopic textile solidified by a matrix member is employed, and the deviation of the thread density is within + or -5%, no disturbance in fibers is caused in stereoscopic forming and anisotropy and ununiformity of the raw material characteristic are avoided. Thus, a stereoscopic diaphragm such as cone, dome or parabolic shape with excellent sound pressure frequency characteristic is obtained, and a forming defect (textile uneven weave, flaw or crack) in the manufacture process is not caused, the yield of product is improved and the versatile sound pressure frequency characteristic is obtained with versatile shape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speaker diaphragm having a three-dimensional shape such as a cone shape, a dome shape, or a parabolic shape.

[Conventional technology]

The most important properties required for a speaker diaphragm are the specific elastic modulus of the material used, that is, V/) (1!!; elastic modulus,
ρ (density) is large. Conventional.

Materials used include natural pulp polymer materials, aluminum, and ceramics, which are selected depending on the shape and size.

Recently, as a material for the diaphragm, there is an f'R fiber-reinforced plastic in which the resin is reinforced using high-modulus carbon fiber. These fiber-reinforced plastics are attracting attention as materials that can be designed to have mechanical properties between the reinforcing material and the matrix by combining fibers, which are reinforcing materials, and resin, which is a matrix. For example, if the carbon fiber mentioned above is compared to a resin,
When composited with a high volumetric filling rate, it has a large porosity compared to ceramics, which has the best noise characteristics as a single material.
It is widely used because it can obtain materials that can be used.

By the way, the characteristics of the diaphragm depend not only on p, which is a material characteristic, but also on its shape.

For example, even if diaphragms of different shapes with the same weight are molded from the same material and their sound pressure frequency characteristics are measured, identical characteristic diagrams will not be obtained. The shapes of diaphragms commonly used in the past include flat plates, cone shapes, dome shapes, and parabolic shapes. - Numerically speaking, diaphragms with shell structures such as cone shapes, dome shapes, and parabolic shapes are flat plates. The reproduction frequency band is wider than that of the planar diaphragm, and the upper limit frequency is also large, so it is used as a high-performance diaphragm.

However, these shell structure diaphragms.

In the high-pitched sound region, split resonance occurs in which two points on the vibration surface vibrate in opposite phases to other points, resulting in a low sound pressure level.

The fiber-reinforced plastic imaging plate used is a plain-woven flat cloth made of high-modulus carbon fiber warp and weft impregnated with resin and press-molded into a cone-shaped, dome-shaped, or parabolic-shaped imaging plate. There is. However, these materials have material characteristics (noise).

The mesh lattice of the fabric exhibits different anisotropy in the side direction and diagonal direction.

This mesh lattice (square) is sheared and deformed into a rhombus when it is shaped into a three-dimensional shape such as a cone shape, a dome shape, and a parabolic shape. This deformation is greatest in the diagonal direction), and the above-mentioned anisotropy is strengthened. For this reason, when a plain-woven plane cloth is used for a cone-shaped, dome-shaped, or parabolic-shaped diaphragm, split resonance tends to occur in high-temperature regions.

As a method to solve this anisotropy, Japanese Patent Application Laid-Open No. 61-495
No. 92 proposes a diaphragm using an annular cloth made up of fibers arranged radially from the center and fibers arranged circumferentially. These exhibit isotropy for axisymmetric loads.

However, since these are flat woven fabrics.

After all, when the fabric is shaped into a three-dimensional shape such as a cone shape, a dome shape, or a parabolic shape, the fabric becomes misaligned and the fiber orientation is disturbed. That is, when molding into a diaphragm having a developable surface such as a straight cone, the annular cloth can be cut and pasted together to form the diaphragm without disturbing the fiber orientation.

However, bonding them together increases the fiber density in the area where they are bonded together as an imaging plate and causes discontinuity of the reinforcing fibers arranged in the circumferential direction, so the material properties (V
p) is no longer isotropic.

Furthermore, when an unbroken circular cloth is shaped into a three-dimensional shape such as a cone shape, a dome shape, or a parabolic shape, the mesh lattice of the circular cloth generates misalignment and wrinkles without shearing deformation, and sometimes The fabric may break. These misalignments and wrinkles not only distort the shape of the imaging plate after molding, but also cause molding defects such as grooves and cracks on the surface, making it difficult to suppress single-division resonance, and also reducing manufacturing yield. Deteriorate.

[Problem to be solved by the invention]

As mentioned above, when conventional flat cloth is used to mold a three-dimensional imaging plate such as a cone shape, dome shape, or parabolic shape, misregistration and fiber disorder occur, which affect the material properties (Vp). Since it is made non-uniform and anisotropic, it is not only impossible to suppress the splitting of the treble region, but also the yield rate in the manufacturing process is poor.

The present invention was made to solve the above-mentioned problems, and by making the material characteristics (%) uniform over the entire shape, one-division resonance can be suppressed, and the sound pressure frequency characteristics are excellent. The purpose is to obtain a diaphragm with good yield.

[Means to solve the problem]

The speaker diaphragm of the present invention is three-dimensionally woven into a curved shape using radial threads extending radially from the center and circumferential threads woven in a direction substantially perpendicular to the radial threads, and a matrix It uses a curved three-dimensional fabric made of wood.

Another invention of the present invention uses diagonal yarns extending radially from the center and circumferential yarns woven in a spiral shape in one circumferential direction, and alternately entwining the adjacent diagonal yarns with each other. Each time the directional yarns are intertwined, the circumferential yarns are woven between the yarns, thereby creating a three-dimensional curved weave as a triaxial woven fabric, and using a curved three-dimensional woven fabric that is solidified with a matrix material. It is.

[Effect]

The speaker diaphragm of the present invention uses a curved three-dimensional fabric woven three-dimensionally into the shape of a speaker. Because it can be molded without causing misalignment, the fibers are arranged in the same state as the orientation design of the woven fabric.
The material characteristics (Vp) of the diaphragm are stabilized and the sound pressure frequency characteristics are excellent.

〔Example〕

Examples of the present invention will be described below.

Example 1 FIG. 1 is a schematic diagram showing the structure of a curved three-dimensional fabric according to Example 1 of the present invention, and (1) is a radial yarn.

(2) is a circumferential thread. Outer diameter I2 (ms inner diameter 3Crr
L, height 5c! In order to form the IL curved cone-shaped honeycomb speaker diaphragm, first, as shown in Figure 1, a curved three-dimensional fabric with the same dimensions and shape is made of carbon fiber (T300. a radial thread fl+ extending radially from , and each radial thread +11
Circumferential yarn (2) was woven in a direction substantially orthogonal to the 3D weave. Further, the yarn density of this fabric was 9 radial yarns and 9 circumferential yarns/cWL, and the deviation in yarn density was within ±5%. One method for obtaining a curved three-dimensional fabric having an equal thread density from the center to the periphery is, for example, a method using a weaving machine as disclosed in Japanese Patent Application No. 62-302909. Next, the skin material 100/11) of the honeycomb diaphragm was impregnated to form a prepreg, and the core material was made of aluminum foil with a thickness of 105 m. A honeycomb core with a cell size of 3/16° and a thickness of 1.5n was prepared and cured at 100°C for 3 hours while being pressed in a mold.

A honeycomb diaphragm was formed. The volume content of fibers in the skin material of this diaphragm (that is, the curved three-dimensional fabric solidified with the matrix material) was 50 cm.

On the other hand, for comparison, a diaphragm with the same size and weight as this honeycomb diaphragm was made of plain woven flat cloth (manufactured by Toshi).

IK, $6142) was molded using the same resin, core material, and curing conditions as described above.

The sound pressure frequency characteristics of both of these diaphragms are shown in the characteristic diagram of FIG. In Fig. 2, the vertical axis represents sound pressure (aB), the horizontal axis represents frequency (Hz), characteristic curve (a) is the curved three-dimensional fabric, and characteristic curve (1) is the case when the plain weave plane fabric is used. Shows sound pressure frequency characteristics.

As is clear from FIG. 2, the honeycomb diaphragm of Example 1 is an excellent imaging plate in which split resonance in the high frequency range is suppressed. This is because the diaphragm of the present invention has an isotropic orientation in advance with respect to the axisymmetric load on the vibration surface, and is woven with equal density in the radial and circumferential directions from the center to the periphery. This is because the high elastic fibers stabilize the sound pressure frequency characteristics.

Example 2 FIG. 3 is a schematic diagram showing the structure of a curved three-dimensional fabric according to Example 2 of the present invention, and is similar to FIG. 1.

(3) is a diagonal yarn, and (4) is a circumferential yarn. To mold a speaker diaphragm whose vibration surface is an ellipse with an oval diameter of 15α, a short circle diameter of 10cIIL, an inner diameter of 3cR, and a height of 51.

First, a curved three-dimensional fabric with the same dimensions and shape was made using carbon fiber (manufactured by Toshi, 7300.1K) and aramid fiber (manufactured by DuPont, 380 denier), and a curved three-dimensional fabric with triaxial orientation was made. The fabric was woven three-dimensionally as shown in Figure 3. The orientation of this fabric is determined by using aramid fibers for the diagonal yarns (3) extending radially from the center and the circumferential yarns (4) that are woven in a spiral shape in the circumferential direction of the carbon fibers. The diagonal direction thread (3) is ±30
2 Circumferential threads (4) are set at 90°, and adjacent diagonal threads (3) are intertwined alternately, and each time a diagonal thread (3) is entwined, a circumferential The thread (4) was woven into the fabric. Further, the number of 1c1n points of adjacent triaxial intersections indicating yarn density was 4.5, and the deviation was within ±8 inches in both the diagonal direction and the circumferential direction. Here, as a method for obtaining this curved three-dimensional fabric, there is, for example, a method using a weaving machine shown in Japanese Patent Application No. 302,910/1982. Next, as a skin material for the honeycomb diaphragm, this fabric was coated with a matrix material of epoxy resin ■ (Epicote 828/) Liethylene Tetramine-1.
The core material is made of aluminum foil with a thickness of 0.05 m. Cell size 3/
A honeycomb core having a diameter of 16° and a thickness of 1.5 nm was prepared and cured at 100° C. for 3 hours while being pressed in a mold to form a honeycomb diaphragm. The fiber volume content of the skin material (that is, the curved three-dimensional fabric consolidated with the matrix) was 45 cm.

In addition, as a comparative example, a diaphragm having the same dimensions and weight as this honeycomb diaphragm was fabricated using a plain weave cloth (manufactured by Toshi, hybrid ratio of 300 denier carbon fiber and 380 denier aramid fiber -2/1). Molded using resin, core material, and curing conditions.

Sound pressure frequency characteristic diagrams for both of these are shown in FIG. Fourth
In the figure, the vertical axis is sound pressure (aB), and the horizontal axis is frequency (aB).
Hz), and the characteristic curve (C) represents the curved three-dimensional fabric, (
d) shows the sound pressure frequency characteristics when a plain woven plane cloth is used.

As is clear from FIG. 4, the two-cam damping plate of Example 2 suppresses the split resonance in the high-frequency range.

It can be seen that this is an excellent diaphragm with improved treble limit frequency.

This is because a diaphragm using a plain-woven plane cloth has different fiber disturbances in the oval direction and the small circular direction during molding, resulting in degraded characteristics, but the diaphragm of this invention has an elliptical vibration surface. Even for non-axisymmetric shapes.

Since a curved three-dimensional fabric is used, there is no occurrence of fiber disorder, resulting in improved properties.

The important point of the diaphragm of the present invention is that the fiber orientation and density can be arbitrarily designed during weaving of the curved three-dimensional fabric, and furthermore, this does not change after molding.

Furthermore, as shown in the embodiments, the diaphragm of the present invention has a thin film skin material that provides bending rigidity.

In the case of honeycomb diaphragm which improves vibration characteristics.

It works extremely effectively. The diaphragm of this invention is.

Even if it is a thin film, it is made of a curved three-dimensional fabric that does not disturb the fiber orientation, so there will be no grooves or wrinkles on the surface of the diaphragm after molding, which will not degrade the vibration characteristics.

According to the present invention, high elastic fibers such as carbon fibers, aramid fibers, and alumina fibers are used for the radial yarns, the circumferential yarns, and the diagonal yarns, and the types thereof are not particularly limited.2 Curved three-dimensional fabrics In order to carry out the detailed material design of
Preferably, the number of filaments is small.

In addition, when designing yarn orientation such as hooks to improve sound pressure frequency characteristics and thread density of the curved three-dimensional fabric used, it is not necessarily necessary to make the entire fabric have an equal width of 2. Orientation.

and may be arbitrarily set according to the optimum thread density. For example, the modulus of elasticity of the radial thread or diagonal thread may be different from that of the circumferential thread, or the modulus of elasticity of the radial thread or diagonal thread may be different at a constant period in the circumferential direction.

Further, in the diaphragm of the present invention, whether the nine-curved three-dimensional fabric is configured with the biaxial orientation as in the first embodiment or the triaxial orientation as in the second embodiment can be selected depending on the shape of the diaphragm.

Sara K again. As the matrix material to be used.

In addition to epoxy resin, the matrix material may be heat-resistant imide, phenol resin, etc., or aluminum, ceramics, etc. depending on the required specifications of the speaker.

〔Effect of the invention〕

As described above, according to the present invention, three-dimensional weaving is performed in a curved shape using radial yarns extending radially from the center and circumferential yarns woven in a direction substantially perpendicular to the radial yarns. However, by using a curved three-dimensional fabric hardened with a matrix material.

According to another aspect of the present invention, using diagonal yarns extending radially from the center and circumferential yarns spirally woven in one circumferential direction, the adjacent diagonal yarns are alternately entwined with each other, Each time the diagonal yarns are intertwined, the circumferential yarn is woven between the yarns, thereby weaving the circumferential yarn in a three-dimensional curved shape as a triaxial fabric, and using a curved three-dimensional fabric that is solidified with a matrix material. In addition, when molding into a three-dimensional shape, no fiber disorder occurs.

Cone shape with excellent sound pressure frequency characteristics due to the absence of anisotropy and non-uniformity in material properties (TVp).

A diaphragm with a three-dimensional shape such as a dome shape or a parabolic shape can be obtained. Furthermore, molding defects (fabric misalignment, creases, etc.) do not occur during the manufacturing process, and the yield of waste products is improved. Also, the material characteristics (Vp) of curved three-dimensional fabrics
This design can be directly reflected on the diaphragm, and has the effect of providing diaphragms with various shapes and various sound pressure frequency characteristics.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the structure of a curved three-dimensional fabric according to an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the sound pressure frequency characteristics of a speaker diaphragm according to an embodiment of the present invention together with a comparative example. FIG. 3 is a schematic diagram showing the structure of a curved three-dimensional fabric according to another embodiment of the present invention, and FIG. 4 is a characteristic diagram showing the sound pressure frequency characteristics of a speaker diaphragm of another embodiment of the present invention together with a comparative example. It is a diagram. In the figure, (1) is a radial yarn, (21 (41 is a circumferential yarn), (3) is a diagonal yarn. In Figure 9, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A curved surface woven three-dimensionally into a curved surface using radial yarns extending radially from the center and circumferential yarns woven in a direction substantially perpendicular to the radial yarns, and hardened with a matrix material. A speaker diaphragm using shaped three-dimensional fabric. (2) Using diagonal yarns that extend radially from the center and circumferential yarns that are woven in a spiral shape in the circumferential direction, the adjacent diagonal yarns are alternately entwined, and each time the diagonal yarns are entwined, A speaker diaphragm using a curved three-dimensional woven fabric which is woven with the circumferential yarns between these yarns to three-dimensionally weave a three-dimensional curved fabric as a three-axis woven fabric and solidified with a matrix material.