JPH08256397

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DESCRIPTION JPH08256397
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
edge for a speaker, and more particularly to an edge for a speaker which can fully exhibit
responsiveness and vibration absorption characteristics.
[0002]
2. Description of the Related Art In a so-called cone type speaker, an annular edge formed of a
rubber elastic body is fixed to a peripheral portion of a cone. The speaker edge is required to be
able to emit vibration of the vibrator as a sound wave with high responsiveness. Furthermore, the
speaker edge can exert a sufficient damping function so that the previous vibration does not
affect the next transmitted vibration in a state where the vibration of the vibrator is continuously
transmitted to the edge. In other words, a large loss factor is required. In addition, at the speaker
edge, it is required to be able to manufacture in a short time.
[0003]
SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a
speaker edge which can fully exhibit the response and the vibration absorbing characteristics.
Another object of the present invention is to provide a speaker edge which can fully exhibit
responsiveness and vibration absorption characteristics and can reduce manufacturing time.
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[0004]
SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above
object, and is characterized by the following constitution. That is, according to the present
invention, there is provided a speaker edge characterized by being formed from a composition
comprising 98 to 50 parts by weight of butadiene-acrylonitrile rubber and 2 to 50 parts by
weight of polyvinyl chloride. Further, according to the present invention, there is provided a
speaker edge formed by injection molding the above-mentioned composition.
[0005]
DETAILED DESCRIPTION OF THE INVENTION The technical feature of the first aspect of the
present invention is that the speaker edge may be described as butadiene-acrylonitrile rubber
(hereinafter referred to as NBR). ) Has a specific amount of polyvinyl chloride blended therein,
which provides a speaker edge capable of sufficiently exhibiting responsiveness and vibration
absorption characteristics.
[0006]
In the present invention, the composition of butadiene-acrylonitrile rubber and polyvinyl chloride
is 2 to 50 parts by weight of polyvinyl chloride, particularly 95 to 70 parts by weight of
butadiene-acrylonitrile rubber, based on 98 to 50 parts by weight of butadiene-acrylonitrile
rubber. On the other hand, 5 to 30 parts by weight of polyvinyl chloride is preferred in view of
temperature dependency (range of 0 ° C. to 30 ° C.). Further, in the present invention, NBR
preferably has an acrylonitrile content of 20 to 50 wt%, particularly 30 to 40 wt%, in order to
increase the loss factor. In the present invention, by compounding the material for the speaker
edge as described above, the mold release of the product is improved, so that it is possible to
fully automate mechanization and make the molding process unmanned.
[0007]
Further, the NBR may be compounded with additives known per se, such as a foaming agent, a
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crosslinking agent, a filler, and a softener. Examples of the foaming agent include benzene
sulfonyl hydrazide and the like. Examples of the crosslinking agent include sulfur and a thiuram
promoter. Examples of the filler include carbon black and mica. Examples of the softener include
DOP and DBP.
[0008]
In the present invention, polyvinyl chloride is a homopolymer of vinyl chloride and a copolymer
of vinyl chloride as a main component with a copolymerizable monomer, such as copolymer of
vinyl chloride and vinyl acetate. It is included with union. Polyvinyl chloride having an average
polymerization degree in the range of 800 to 3000, particularly 1300 to 1800, is preferable in
terms of compatibility when blended with rubber. As polyvinyl chloride, PX-NHA (trade name)
manufactured by Sumitomo Chemical Co., Ltd. can be suitably used.
[0009]
In addition, the technical feature of the other aspect of the speaker edge according to the present
invention lies in that the speaker edge having the above-mentioned composition is formed by
injection molding, whereby the manufacturing time is shortened compared to press molding.
Thus, the cost of the speaker edge is reduced.
[0010]
According to the present invention as set forth above, according to the present invention, it is
possible to provide a speaker edge which can sufficiently exhibit the response and the vibration
absorbing characteristics.
Further, according to the invention of claim 2, it is possible to provide an edge for a speaker
which can sufficiently exhibit the response and the vibration absorbing characteristics and can
shorten the manufacturing time.
[0011]
The invention will now be described by way of example. Polyvinyl chloride and butadiene-
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acrylonitrile rubber are mixed at a blend ratio of 20:80, 45 parts by weight of carbon, 5 parts by
weight of zinc oxide (ZnO), 1 part by weight of stearic acid, 10 parts by weight of plasticizer with
respect to 100 parts by weight of polymer A compound obtained by adding 1 part by weight of
sulfur and 2 parts by weight of a thiuram based accelerator was injection-molded at 175 ° C. for
1.5 minutes to obtain a speaker edge. The loss factor of the obtained speaker edge is shown in
Table 1, and the frequency characteristic is shown by curve A in FIG. As shown in FIG. 1, in the
present embodiment, the curve is positioned on the upper side, that is, on the high sound
pressure level side of Comparative Example 2 (curve shown by symbol B in FIG. 1) described
later. It turned out that responsiveness is better than 2.
[0012]
Comparative Example 1 50 parts by weight of carbon, 5 parts by weight of zinc oxide (ZnO), 1
part by weight of stearic acid, 10 parts by weight of plasticizer, 1 part by weight of sulfur,
thiuram based accelerator 2 with respect to 100 parts by weight of butadiene-acrylonitrile
rubber The compound added with parts by weight was press vulcanized and formed at 175 ° C.
for 3 minutes to obtain an edge for a speaker. The loss factor of the obtained speaker edge is
shown in Table 1.
[0013]
Comparative Example 2 A blend of 45 parts by weight of carbon, 8 parts by weight of plasticizer,
1 part by weight of stearic acid, 1.5 parts by weight of sulfur and 2 parts by weight of thiuram
based accelerator relative to 100 parts by weight of butyl rubber polymer Press vulcanization
molding was performed under molding conditions of 3 ° C. for 3 minutes to obtain an edge for a
speaker. The loss coefficient (tan δ) of the obtained speaker edge is shown in Table 1, and the
frequency characteristic is shown by curve B in FIG.
[0014]
As shown in Table 1 above, the loss factor of the example is larger than the loss factor of
Comparative Example 1 and Comparative Example 2, and it is clear that the example is excellent
as a speaker edge.
[0015]
Brief description of the drawings
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[0016]
1 is a diagram showing a frequency characteristic curve of a speaker in which the speaker edge
according to the present invention is used, where A indicates the frequency characteristic of the
edge according to the present invention, and B indicates the frequency characteristic of the
conventional edge. There is.
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