JPH04340899A - Diaphragm for speaker and its manufacture - Google Patents

Abstract

PURPOSE:To provide a diaphragm for speaker of which transmission loss between a voice coil and the diaphragm is little and acoustic characteristic is excellent. CONSTITUTION:A voice coil bobbin 3 composed of polyimid film is provided with a petaloid notch part 3a on which epoxy resin is applied. After the voice coil bobbin 3 is inserted into the voice coil bobbin insertion part of a recessed type die 5a of a diaphragm forming die 5, the integration is performed by performing thermal press molding by the diaphragm forming die 5 for what is made to couple by epoxy resin to the corn state after performing the plain weave of polyimide fiber bundle and carbon fiber bundle of polyimide fiber having a stretch strength of 300kg/mm<2> and a stretch elastic modulus of 14000kg/mm<2> so that the both fiber bundles may cross each other, and at the same time, by performing thermal melt-sticking of the voice bobbin 3 on a diaphragm 1 by coupling the epoxy resin which is the coupling resin of the diaphragm 1 with the epoxy resin applied on the voice coil bobbin 3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm for a speaker in an electroacoustic transducer and a method for manufacturing the same.

0002

[Prior Art] As is well known, a diaphragm for a speaker needs to have low density and high elasticity in order to increase the output level of the speaker, and also to have high elasticity in order to widen the reproduction band of the speaker. In addition, large internal loss is required in order to reduce distortion caused by split vibration of the diaphragm.

[0003] Furthermore, the voice coil bobbin is required to be lightweight, thin, and highly rigid in order to increase conversion efficiency, and it is also required to have excellent heat resistance so that it will not be deformed by the Joule heat of the current flowing through the coil. Ru.

[0004] Conventional speaker diaphragms are made by bonding woven fabrics, non-woven fabrics, etc. of highly elastic materials such as glass fibers and carbon fibers or mixtures of different types of highly elastic materials using resin. Then, on the diaphragm, paper,
A voice coil bobbin made of metal such as aluminum, resin, or woven fabric made of highly elastic fibers is bonded to it. There are also devices in which the diaphragm and the voice coil bobbin are integrally molded from resin by injection molding.

[0005]

In conventional speaker diaphragms having such a structure, diaphragms made of glass fibers, carbon fibers, etc. have high elasticity but low internal loss. In addition, voice coil bobbins made of paper are inferior in rigidity and heat resistance, those made of metals such as aluminum or woven fabric made of highly elastic fibers are heavy, and those made of resin have poor heat resistance. There are many things that are inferior to. Since the diaphragm and the voice coil bobbin are made of different materials, they are attached using adhesive, but the adhesive increases the weight of the diaphragm, causing vibrations from the voice coil. There was a drawback that transmission loss occurred at the adhesive part of the transmission to the plate. In addition, in the case where the diaphragm and voice coil bobbin are integrally molded with resin by injection molding, the elasticity of the diaphragm is low, so in order to increase the elasticity, it is necessary to add about 20 to 30% filler by weight. It is necessary to mix the diaphragm into the diaphragm, which has the disadvantage of increasing the weight of the diaphragm.

Therefore, the present invention eliminates the drawbacks of the conventional example and provides a diaphragm having high elasticity and appropriate internal loss,
To provide a diaphragm for a speaker and a method for manufacturing the same, in which a voice coil bobbin having high rigidity, excellent heat resistance, and light weight can be attached without increasing weight, and transmission loss between the diaphragm and the voice coil can be reduced. The purpose is to

[0007]

[Means for Solving the Problems] A speaker diaphragm according to the present invention for achieving the above object has a tensile strength of 30
0kg/mm2 or more, tensile modulus 14000kg
/mm2 or more, a woven fabric is made of polyimide fibers and carbon fibers, and the diaphragm 1 is constructed of the woven fabric and a thermoplastic resin or thermosetting resin for bonding the woven fabric. It is characterized in that a voice coil bobbin 3 made of polyimide film is heat-sealed and integrated into the body.

[0008] Furthermore, in the method for manufacturing the speaker diaphragm, after inserting the voice coil bobbin 3 into the diaphragm mold 5,
The present invention is characterized in that, at the same time as the diaphragm 1 is molded, the resin for bonding the woven fabric and the voice coil bobbin 3 are thermally fused and integrated.

Next, the method for manufacturing the speaker diaphragm includes coating a part of the voice coil bobbin 3 with the same type of resin as the bonding resin of the diaphragm 1, and heat-sealing the diaphragm 1 and the voice coil bobbin 3. It is characterized by being integrated.

0010

[Function] In the speaker diaphragm with this structure and its manufacturing method, the diaphragm uses a woven fabric of polyimide fiber and carbon fiber bonded with resin, so it has high elasticity and appropriate internal loss. Since a polyimide film is used for the voice coil bobbin, a lightweight voice coil bobbin with high rigidity and excellent heat resistance can be obtained. Furthermore, since the diaphragm and voice coil are made of the same material, polyimide, the diaphragm and voice coil bobbin can be heat-sealed and integrated at the same time as the diaphragm is molded, without increasing the weight of the diaphragm. , transmission loss between the diaphragm and the voice coil can be reduced. Moreover, the transmission loss between the diaphragm and the voice coil can be reduced even if the voice coil bobbin is coated with a resin of the same type as the bonding resin of the diaphragm and then heat-sealed and integrated.

[0011]

[Example] Referring to FIG. 1, an example of the present invention will be described in detail.
FIG. 1 is a cross-sectional view of a speaker diaphragm and a diaphragm molding die in an embodiment of the present invention, in which 1 is a diaphragm, 2 is a voice coil, 3 is a voice coil bobbin, 3a is a petal-shaped notch, and 4 is an epoxy resin. 5 is a diaphragm mold, 5a is a concave mold, and 6 is a voice coil bobbin insertion portion.

In the embodiment of the present invention, a voice coil bobbin 3 made of a polyimide film is provided with a petal-shaped notch 3a, an epoxy resin 4 is applied to the petal-shaped notch 3a, and a concave mold of a diaphragm mold 5 is formed. After inserting the voice coil bobbin 3 into the voice coil bobbin insertion part 6 of the mold 5a, a polyimide fiber bundle (1000 filaments) of polyimide fibers having a tensile strength of 300 kg/mm2 and a tensile modulus of 14000 kg/mm2 and a carbon fiber bundle (1000 filaments) The diaphragm 1 is plain woven at a fiber bundle density of 12.5 fibers/inch so as to intersect with each other, and bonded by epoxy resin.The diaphragm 1 is then heated and press-molded into a cone shape using a diaphragm mold 5, and at the same time the diaphragm 1 is bonded. The epoxy resin is combined with the epoxy resin 4 applied to the voice coil bobbin 3, and the voice coil bobbin 3 is heat-sealed to the diaphragm 1 and integrated. In this way,
A speaker diaphragm according to the present application is obtained.

Above, the speaker diaphragm and the method for manufacturing the same according to the present invention have been described in detail based on embodiments that are considered to be representative. However, the embodiments of the speaker diaphragm and the method for manufacturing the same according to the present invention are, for example, , presence or absence of a notch in the voice coil bobbin and its shape, presence or absence of resin applied to the voice coil bobbin, method of weaving polyimide fibers and carbon fibers, material of thermoplastic resin or thermosetting resin for bonding polyimide fibers and carbon fibers, etc. However, the structure is not limited to the structure of the above embodiment, and may be modified as appropriate as long as it has the constituent features described in the claims, exhibits the function of the present invention, and has the effects described below. It can be implemented by

[0014]

[Effects] In the speaker diaphragm according to the present invention, the elasticity (Young's modulus E) and the internal loss (
tan δ), the conventional diaphragm has E
= 1500 kg/mm2 and tan δ = 0.018, whereas in the diaphragm of the example, E = 1350 kg/mm2.
mm2, tan δ = 0.030, and although the elasticity (Young's modulus E) of the diaphragm of the example was slightly smaller than that of the conventional diaphragm, a sufficiently high elasticity was still obtained, and the internal loss (tan δ) was It is considerably larger than the conventional diaphragm.

[0015] Furthermore, since the voice coil bobbin was made of polyimide film,
A lightweight, highly rigid product with excellent heat resistance was obtained.

Next, in FIG. 2, A. A diaphragm made of a woven fabric made of polyimide fibers and carbon fibers bonded together using an epoxy resin, and a voice coil bobbin made of a polyimide film bonded together with an adhesive; B. 3 shows sound pressure frequency characteristics with a speaker diaphragm in an example of the present invention.

As is clear from FIG. 2, in the speaker diaphragm according to the embodiment of the present invention, the diaphragm and the voice coil bobbin are integrated by heat fusion, which reduces the transmission loss between the diaphragm and the voice coil. This eliminates the peaks and dips that were seen in the mid-range of the frequency response even when the diaphragm and voice coil bobbin are bonded together, and the frequency response in the mid-range and high range is flattened, creating a speaker diaphragm with excellent acoustic properties. Obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a speaker diaphragm and a diaphragm molding die in an embodiment of the present invention.

FIG. 2 shows the sound pressure frequency characteristics of the speaker diaphragm in the same example.

[Explanation of symbols]

1 Diaphragm 2 Voice coil 3 Voice coil bobbin 3a Petal-shaped notch 4 Epoxy resin 5　　　Diaphragm molding mold 5a Concave mold 6 Voice coil bobbin insertion part

Claims (3)

[Claims] 1. A woven fabric made of polyimide fibers and inorganic or organic fibers having a tensile strength of 300 kg/mm 2 or more and a tensile modulus of 14000 kg/mm 2 or more, and a thermoplastic resin for bonding the woven fabric. Or a diaphragm made of thermosetting resin (
The diaphragm for a speaker according to 1), characterized in that a voice coil bobbin (3) made of a polyimide film is heat-sealed and integrated with the diaphragm (1). 2. After inserting the voice coil bobbin (3) into the diaphragm molding die (5), the diaphragm (1) is molded, and at the same time, a resin for bonding the woven fabric and the voice coil bobbin (3) are molded. 2. The method of manufacturing a speaker diaphragm according to claim 1, wherein the diaphragm for a speaker is integrated by heat-sealing. 3. Applying the same type of resin as the bonding resin of the diaphragm (1) to a part of the voice coil bobbin (3),
3. The method of manufacturing a speaker diaphragm according to claim 2, wherein the diaphragm (1) and the voice coil bobbin (3) are integrated by thermal fusion.