JP3143759B2 - Speaker box - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker box having a front plate portion on which a speaker is mounted, wherein at least the front plate portion is formed of a polypropylene resin material.

[0002]

2. Description of the Related Art In an audio system including a cassette tape player, a digital audio disk player, and the like as main components, a speaker may be housed and arranged in an independent speaker box. Many. A speaker housed and used in such an independent speaker box is, for example, mounted on the inner surface side of a front plate portion constituting the speaker box, and its sound emission characteristics are formed behind the speaker. Not only is it affected by the shape and capacity of the acoustic space in the speaker box, the arrangement of the sound absorbing members in the acoustic space in the speaker box, but also affected by the material forming the speaker box. In other words, in order to obtain good sound emission characteristics of a speaker housed and used in a speaker box so that a reproduced sound with excellent fidelity is emitted, the members forming the speaker box must have a sound propagation speed that propagates inside the speaker box. That is, the sound velocity √ (E / ρ) (E is the longitudinal elastic modulus, ρ is the density) is increased, and the internal loss tan of the sound that defines the acoustic vibration characteristics
δ is required to be an appropriate value.

Conventionally, the mainstream speaker box is formed of a plywood member called a particle board. However, when the speaker box is formed by the particle board, the particle board has a sound velocity inside the speaker box.
Since it is difficult to control (E / ρ) and the internal loss tan δ of the sound to have a desired value, it is necessary to obtain good sound emission characteristics of the speaker housed in the speaker box. , Speaker box shape, dimensions,
The sound speed of the particle board, including the internal structure
/ Ρ), internal loss of sound, tan δ, etc., it is required to design in accordance with the acoustic characteristics, and the degree of freedom in designing the speaker box is significantly restricted.

[0004]

Under the circumstances described above, the acoustic characteristics including the speed of sound √ (E / ρ) and the internal loss of sound tanδ can be easily controlled, and the workability is excellent. In addition, there is a demand for a speaker box that is formed using a material that can provide a good appearance and that has improved design flexibility. In order to meet such a demand, a speaker box formed by using a synthetic resin material instead of a particle board has been proposed. In this case, the synthetic resin material is made of polystyrene, acrylonitrile-butadiene. -A resin composition based on styrene, polymethyl methacrylate, polypropylene or the like;

However, in the conventionally proposed speaker box formed by using such a resin composition, the above-mentioned demand is sufficiently satisfied, and excellent sound quality is obtained from the speaker contained therein. Nothing has been made to play the sound.

In view of the above, the present invention provides a sound velocity √ (E /
ρ), internal loss of sound It is easy to control acoustic characteristics including tan δ, etc., and it is formed by using a synthetic resin material that is excellent in workability and can provide a good appearance. It is an object of the present invention to provide a speaker box whose degree is greatly improved.

[0007]

In order to achieve the above-mentioned object, a speaker box according to the present invention has a front plate portion to which a speaker is attached, and at least the front plate portion is based on 100 parts by weight of a polypropylene resin. It is formed of a polypropylene-based resin composition containing 5 to 35 parts by weight of an organic filler and 5 to 35 parts by weight of a fine hollow body. And as an organic filler,
For example, a material selected from the group consisting of wood flour, coconut husk flour, rice husk flour, cork flour, cellulose flour, wood pulp, paper chips, and crushed chips is used. For example, fine glass hollow particles having a pressure resistance of 500 kg / cm ² or more are used.

[0008]

In the loudspeaker box according to the present invention, the front panel portion which has the greatest influence on the sound emission characteristics of the loudspeaker accommodated in the loudspeaker box is different from other portions or different from the other portions. In the same manner as in the above section, the organic fillers 5 to 35 per 100 parts by weight of the polypropylene resin are used.
It is formed of a polypropylene-based resin composition in which parts by weight and 5 to 35 parts by weight of a minute hollow body are mixed. In the polypropylene-based resin composition, the amount of the organic filler mixed in the range of 5 to 35 parts by weight and the amount of the micro hollow body mixed in the range of 5 to 35 parts by weight are selected. Thus, the acoustic characteristics including the speed of sound √ (E / ρ) and the internal loss of sound tanδ are easily controlled. Therefore, in the speaker box according to the present invention, at least the front plate portion to which the speaker is attached has a sound velocity √ (E / ρ).
Is set to a relatively large value and the internal loss of sound t
anδ is set to an appropriate value in consideration of dimensions and the like, so that the speaker emits reproduced sound of excellent sound quality, and at least the front plate portion is formed of a polypropylene resin. The composition is excellent in processability by the mixing amount of the organic filler being in the range of 5 to 35 parts by weight and the mixing amount of the fine hollow body being in the range of 5 to 35 parts by weight, It is assumed that a good appearance is obtained, whereby the sound velocity √ (E / ρ), the internal loss of sound t
Along with easy control of acoustic characteristics including an δ and the like, the degree of freedom in designing is remarkably improved.

[0009]

FIG. 2 is a front view showing an example of a speaker box according to the present invention, and FIG. 1 is a sectional view showing a section taken along line II in FIG.

1 and 2 show a front plate portion 11, a top plate portion 12, a bottom plate portion 13, a pair of side plate portions 14 facing each other, and a rear plate portion facing the front plate portion 11. 15 is provided. A circular opening 18 is formed in the front plate portion 11 at a position in front of the vibrating cone portion of the speaker 17 attached to the inner surface thereof, as indicated by a virtual line in FIG. A plurality of small-diameter mounting holes 19 used for mounting the speaker 17 are provided around the circular opening 18. Further, the front plate portion 11 has a duct hole 21 provided below the circular opening 18 with a duct forming portion 20 extending from the inner surface toward the rear plate portion 15.
The examples shown in FIGS. 1 and 2 are bass-reflex type speaker boxes.

Each of the front plate portion 11, the top plate portion 12, the bottom plate portion 13, the side plate portion 14, the back plate portion 15, and the duct forming portion 20 is formed of a polypropylene resin composition. The resin composition is
5 to 35 parts by weight of an organic filler and 5 to 35 parts by weight of a minute hollow body are mixed with 100 parts by weight of a polypropylene resin.

As the polypropylene resin, a propylene homopolymer, a copolymer of propylene with an olefinic hydrocarbon other than propylene such as ethylene and 1-butene, and an unsaturated carboxylic acid such as maleic anhydride are graft-polymerized. Modified polypropylene or the like is selected and used. Further, as the organic filler, one kind is selected from a group including wood flour, coconut husk flour, rice husk flour, cork flour, cellulose flour, wood pulp, paper chips, and crushed pieces, Alternatively, two types are selected and they are mixed and used. Regardless of which of these organic fillers is selected, it is desirable that the average particle size be 120 μm or less. Further, as the minute hollow body, for example, fine glass hollow particles are used. It is desired that such a minute hollow body has a pressure resistance of not less than 500 kg / cm ² and an average particle diameter of not more than 100 μm, particularly preferably not more than 60 μm. It is desired that the micro hollow body has an average particle density of 0.5 to 0.7 g / cm ³ in the polypropylene resin composition.

As described above, the polypropylene resin 10
0 parts by weight, 5 to 35 parts by weight of an organic filler whose average particle diameter is desirably 120 μm or less, and a pressure resistance of 500 kg / cm ² or more, and the average particle diameter is A polypropylene resin composition containing 5 to 35 parts by weight of a micro hollow body, which is desirably 100 μm or less, has a relatively low density ρ and high rigidity, and has a comparatively high sound velocity √ (E / ρ). In addition to the target value, it is assumed that the internal loss tan δ of the sound takes an appropriate value. By the way, when only the organic filler is mixed with the polypropylene resin and the minute hollow body is not mixed, the rigidity is increased, but the density is not reduced, and the polypropylene resin is When only the minute hollow body is mixed and the organic filler is not mixed, the density δ is reduced, but the rigidity is not increased, and the internal loss tan δ of sound is significantly reduced. The improvement in rigidity due to the mixing of the organic filler is particularly remarkable due to their good dispersibility when wood flour or chaff flour having an average particle size of 120 μm or less is used as the organic filler. It is assumed.

The reason that the mixing ratio of the organic filler to the polypropylene resin is selected such that the organic filler is 5 to 35 parts by weight with respect to 100 parts by weight of the polypropylene resin is that 100 parts by weight of the polypropylene resin. When the amount of the organic filler is less than 5 parts by weight with respect to parts by weight,
It has been experimentally confirmed that the reduction of the density ρ and the improvement of the rigidity due to the cooperative action with the minute hollow body mixed with the polypropylene resin cannot be sufficiently achieved, and that good acoustic characteristics cannot be obtained. When the organic filler exceeds 35 parts by weight based on 100 parts by weight of the polypropylene resin,
This is because it has been experimentally confirmed that the appearance of the surface is degraded in the state where the speaker box is formed, and that the impact resistance is also reduced.

Similarly, the mixing ratio of the micro hollow body to the polypropylene resin is selected so that the ratio of the micro hollow body is 5 to 35 parts by weight with respect to 100 parts by weight of the polypropylene resin. When the micro hollow body is less than 5 parts by weight with respect to 100 parts by weight, it has been experimentally confirmed that it is difficult to reduce the weight, and also, based on 100 parts by weight of the polypropylene resin. If the minute hollow body exceeds 35 parts by weight, it is considered that the internal loss tan δ of sound is reduced and good acoustic characteristics are not obtained, and the appearance of the surface is deteriorated in a state where the speaker box is formed. This is because it was confirmed experimentally.

As described above, the polypropylene resin 10
0 parts by weight, 5 to 35 parts by weight of an organic filler whose average particle diameter is desirably 120 μm or less, and a pressure resistance of 500 kg / cm ² or more, and the average particle diameter is A speaker box formed of a polypropylene resin composition mixed with 5 to 35 parts by weight of a minute hollow body desirably 100 μm or less includes, for example, a front plate portion 11, a top plate portion 12, and a bottom plate portion 13. ,
Side plate portion 14, back plate portion 15, and duct forming portion 20
Are individually formed by a polypropylene-based resin composition, and are obtained by assembling them. At this time, in forming each of the front plate portion 11, the top plate portion 12, the bottom plate portion 13, the side plate portion 14, the back plate portion 15, and the duct forming portion 20, a polypropylene resin, an organic filler, and a minute hollow body are used. May be subjected to direct molding of each part after being dry-blended, but differently, a polypropylene-based resin, an organic-based filler, and a minute hollow body are mixed with a mixer device, an extrusion device, or the like. It is preferable that a method is used in which after kneading is performed to form a composite composition under the use of, is used for molding each part.

Table 1, Table 2, Table 3, Table 4, Table 5, and Table 6
Are different from each other in the mixing amount of the organic filler and the minute hollow body in the plurality of speaker boxes according to the present invention (used in the polypropylene-based resin composition used in the present invention; ) And a plurality of other speaker boxes (different materials used; comparative example) were compiled based on the results of the experiment with the prepared examples (Experimental Examples 1 to 7) and Comparative Examples The results of comparison with Comparative Examples 1 to 13 are shown. In the experiment, the measurement and calculation of the physical properties (sound speed and internal loss) of the material, the sound quality evaluation of the sound emitted from the loudspeaker housed therein, and the appearance evaluation of each of the plurality of experimental examples and the plurality of comparative examples Was to be performed. Each of the plurality of experimental examples and the plurality of comparative examples was a bass-reflex type speaker box, and speakers were mounted on the inner surface side of the front plate portion.

The sound quality is evaluated by actually listening to the sound emitted from the speaker and applying the original sound reproduction degree to the five-level evaluation. The appearance evaluation is performed by visually judging the silver streak on the surface. This was done by applying a grading scale. The five-grade evaluation in the sound quality evaluation is excellent: A, somewhat excellent: AB, standard (equivalent to that made of a particle board): B, slightly poor: BC, poor: C
In addition, the three-grade evaluation in the appearance evaluation was as follows: no silver streak: a, silver streak was present but not noticeable: b, silver streak was noticeable: c. In Tables 1 and 2, the micro hollow body: V-
1, V-2 and V-3 have a density (g / cm ³ ) and a nominal compressive strength (kg / cm ² ) of 0.60 and 700, 0.38 and 280, and 0.50 and 100 to 120.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

[Table 6]

Table 7 shows Experimental Examples 1 to 7 and Comparative Examples 1 to 7.
In each of Comparative Examples 13 and 13, the state of the mixed amount of the fine hollow body and the organic filler is shown.

[0026]

[Table 7]

In Tables 1 to 6, it is found that the speaker boxes according to the present invention, which are experimental examples 1 to 7, obtain "A" or "AB" in the sound quality evaluation and "a" in the appearance evaluation. Or "b", which is superior in both good sound quality evaluation and appearance evaluation as compared with Comparative Example 1 to Comparative Example 13 which are speaker boxes different from the speaker box according to the present invention. Understood.
In addition, at least in Experimental Examples 1 to 7, the change in the amount of the organic filler mixed in the range of 5 to 35 parts by weight, and the change in the amount of the fine hollow body in the range of 5 to 35 parts by weight.音 (E / ρ) and internal loss of sound tan
It can be seen that δ is changed. In Table 7, “ratio” means “comparative example”, and “real” means “experimental example”. And the dotted line
The portion surrounded by () is a range corresponding to the speaker box according to the present invention.

According to Tables 1 to 7, the speaker box according to the present invention has a sound velocity √ (E / ρ) of each component.
It is easy to control the acoustic characteristics including the internal loss of sound, and the sound speed is set to a relatively large value, and the internal loss of sound tanδ is set to an appropriate value in consideration of dimensions etc. It is assumed that the speaker emits reproduced sound of excellent sound quality, and the polypropylene resin composition has an amount of an organic filler mixed within a range of 5 to 35 parts by weight and a fine hollow body. Is in the range of 5 to 35 parts by weight, excellent workability and good appearance can be obtained, and the acoustic characteristics can be easily controlled. It is confirmed that the degree of freedom is significantly improved.

In the above description, the polypropylene-based resin composition forming the speaker box according to the present invention comprises the organic-based filler 5 per 100 parts by weight of the polypropylene-based resin.
However, it is described that the polypropylene-based resin composition for forming the speaker box according to the present invention is a polypropylene-based resin, The polypropylene resin composition forming the speaker box according to the present invention does not mean that only the organic filler and the minute hollow body are used as constituents. In addition to 5 to 35 parts by weight of the system filler and 5 to 35 parts by weight of the minute hollow body, it means that other components are included as necessary. Examples of components other than the polypropylene resin, the organic filler, and the fine hollow body include an antioxidant, an antistatic agent, a dispersant, a flame retardant, an ultraviolet absorber, an organic peroxide, a lubricant, and a colorant. Is mentioned.

Further, in the example of the speaker box according to the present invention shown in FIGS.
Each of the top plate portion 12, the bottom plate portion 13, the side plate portion 14, the back plate portion 15, and the duct forming portion 20 is composed of 5 to 35 parts by weight of an organic filler and 100 parts by weight of a polypropylene resin, and Although the speaker box according to the present invention is not limited to such an example, at least the front plate portion is made of 100 parts by weight of the polypropylene resin. What is necessary is just to be formed of a polypropylene-based resin composition in which 5 to 35 parts by weight of an organic filler and 5 to 35 parts by weight of a minute hollow body are mixed with respect to parts. The front plate portion has a speaker attached to its inner surface side and is a portion that has the greatest influence on the sound emission characteristics of the speaker housed in the speaker box. Therefore, at least the front plate portion is based on 100 parts by weight of the polypropylene resin. 5 to 35 parts by weight of an organic filler and 5 to 3 minute hollow bodies
The object of the present invention is achieved and desired effects can be obtained by being formed from a polypropylene resin composition mixed with 5 parts by weight.

[0031]

As is apparent from the above description, in the speaker box according to the present invention, the front panel portion which has the greatest influence on the sound emission characteristics of the speaker accommodated therein is different from the other portions. Differently or similarly to other parts, a polypropylene-based resin composition comprising 5-35 parts by weight of an organic filler and 5-35 parts by weight of a fine hollow body mixed with 100 parts by weight of a polypropylene-based resin is used. Formed, thereby resulting in the speed of sound √ (E / ρ), the internal loss of sound t
It is assumed that acoustic characteristics including an δ and the like are easily controlled. Therefore, in the speaker box according to the present invention, at least the front plate portion to which the speaker is attached has a sound speed.
(E / ρ) takes a relatively large value, and the internal loss tan δ of the sound takes an appropriate value in consideration of the dimensions and the like, so that the speaker produces a reproduced sound of excellent sound quality. In addition, at least the front plate portion has a polypropylene resin composition forming the same, the mixed amount of the organic filler is in the range of 5 to 35 parts by weight, and the mixed amount of the fine hollow body is 5 to 35 parts by weight. By setting the range of the part, the workability is excellent and a good appearance is obtained, whereby the sound velocity √ (E / ρ), the internal loss of sound tan
Along with the fact that the acoustic characteristics including δ and the like are easily controlled, the degree of freedom in designing is remarkably improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a speaker box according to the present invention.

FIG. 2 is a front view showing an example of the speaker box according to the present invention, and a cross section taken along line II of FIG. 1 is shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Front plate part 12 Top plate part 13 Bottom plate part 14 Side plate part 15 Back plate part 17 Speaker 18 Circular opening 20 Duct formation part 21 Duct hole

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsuyoshi Urano 3600 Gezu, Kita-gaiyama, Komaki-shi, Aichi Tokai Rubber Industries Co., Ltd. (72) Inventor Yoshinori Takahashi 1-1-1, Mikage-cho, Tokuyama-shi, Yamaguchi Tokuyama Soda Co., Ltd. (72) Inventor Hitoshi Inada 1-1, Mikage-cho, Tokuyama-shi, Yamaguchi Pref. Tokuyama Soda Co., Ltd. (72) Inventor Kazuo Fujii 1-1, Mikage-cho, Tokuyama-shi, Yamaguchi Pref. 56) References JP-A-3-223355 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04R 1/02 101 C08K 7/22 C08L 23/12

Claims (5)

(57) [Claims] 1. A front plate portion to which a speaker is attached, wherein at least the front plate portion has 5 to 35 parts by weight of an organic filler and 5 to 35 parts by weight of a minute hollow body with respect to 100 parts by weight of a polypropylene resin. A speaker box formed of a polypropylene resin composition mixed therein. 2. The organic filler is wood flour, coconut husk flour, rice hull flour, cork flour, cellulose flour, wood pulp, paper fines,
The speaker box according to claim 1, wherein the speaker box is selected from a group including crushed pieces. 3. The speaker box according to claim 1, wherein the minute hollow body is made of fine glass hollow particles. 4. The speaker box according to claim 1, wherein the minute hollow body has a pressure resistance of 500 kg / cm ² or more. 5. A speaker box wherein a front plate portion and other portions are entirely formed of the polypropylene resin composition.