JPS6332320B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a speaker box for housing speakers of televisions, stereos, radios, etc., and provides a speaker box that prevents the generation of abnormal sounds, reduces distortion, and provides normal sound pressure frequency characteristics of the speakers. It is. Conventionally, box materials for speakers such as TVs, stereos, radios, etc. and speaker systems (hereinafter referred to as "speaker box materials") have been synthesized into plywood and small pieces of wood and other plant fibers using raw materials such as lauan, beech, pine, and birch. Particle board, which is artificially formed by applying a resin adhesive, has been used. However, boxes made of these materials have low elastic modulus and bending rigidity, and when the speaker is driven with a constant power, the box may generate abnormal noise, or peaks and valleys may occur in the sound pressure-frequency characteristics of the speaker. There were negative effects as the distortion rate increased. The present invention eliminates the above-mentioned drawbacks of the conventional art, and uses a corrugated board made from a fiberboard into a corrugated cardboard shape as a speaker box. The manufacturing process of the fiber boat is shown below. The raw material is wood such as coniferous trees, which is cut into small pieces using a chipper about 3 to 5 mm thick, 30 mm long, and 20 mm wide. A thermomechanical pulping method was used to turn the chipped raw material into fibers. This process uses a high-pressure steamer to process about 20 chips.
Steam in saturated steam of Kg/ ^cm2 for 30 to 40 seconds, then increase the steam pressure to about 70Kg/ ^cm2 and hold for 1 to 5 seconds, then open the discharge valve to release the chips and pulp. Ta. The pulp defibrated by steaming was further refined using a disc ironer, and the freeness (furnace water level) was adjusted to 20 to 80 D.F.sec. Next, add 0.5 to 4 ml of water-soluble phenolic resin or water-soluble melamine resin to the purified pulp liquid as a sizing agent.
%, and a fixing agent such as aluminum sulfate or hydrochloric acid was added, followed by papermaking. The paper-made wet sheet is dried and solidified using a hot press or the like. Heat-pressure solidification was carried out at a pressure of 50-70 kg/cm ² and a temperature of 180°-250° C. for 3 minutes to form a fiberboard. The fiberboard (approximately 1 mm thick) formed by the above process is made into a corrugated board having a two-layer structure of a flat plate 1 and a corrugated plate 2, as shown in FIG. The corrugated plate 2 was subjected to secondary processing using a roller having a corrugated shape, and a polyamide hot melt adhesive was used for adhesion. Note that the radius of curvature of the corrugated plate 2 is 5 mm. When compared with conventional plywood or particle board, the corrugated board produced in this way has a greatly increased bending rigidity due to the thickness effect under conditions of constant weight, and as a result, speakers using this The box has the effect of flattening the sound pressure-frequency characteristics of the speaker and reducing distortion. Examples of the present invention will be described in more detail below. Example 1 In the production of fiberboard, the freeness of the pulp used was adjusted to about 20D.F.sec, the amount of water-soluble phenol resin added was 0 to 4%, and the heat-pressure solidification was performed at a pressure of 60Kg/cm ² and a temperature The test was carried out at 200°C for 3 minutes. FIG. 2 shows the relationship between the amount of water-soluble phenolic resin added and the flexural modulus of the prepared sample. Example 2 In the production of fiberboard, the freeness of the pulp used was adjusted to about 20 D.F.sec, the amount of water-soluble melamine resin added was 0 to 4%, and the heat-pressure solidification was performed at a pressure of 60 Kg/cm ² and a temperature The test was carried out at 200°C for 3 minutes. FIG. 3 shows the relationship between the amount of water-soluble melamine resin added and the flexural modulus of the prepared sample. FIG. 4 shows a speaker box using the materials of Examples 1 and 2 above. As is clear from Figures 2 and 3, in both Examples 1 and 2, as the amount of sizing agent added increases, the bending elastic modulus of the material increases. This is an important physical property value that indicates the evaluation of . If this value is small, abnormal noise will occur in the box, peaks and troughs will occur in the sound pressure-frequency characteristics of the speaker, and the distortion rate will increase. Table 1 shows a comparison of the physical properties of the veneer material using lauan material, Example 1, and Example 2 as a comparison with conventional box materials.

[Table] Table 2 shows that a speaker box with an internal volume of 6 was manufactured using the materials of Examples 1 and 2.
It shows the acceleration at the center of the buff-full surface when driving a 10cm diameter speaker with each input (8Ω impedance). As described above, the boxes of Examples 1 and 2 have small accelerations and do not vibrate much, so they are the most suitable materials for the boxes.

[Table] The present invention has the above structure, and the speaker box material of the present invention has a large bending elastic modulus, so no abnormal noise is generated, and the sound pressure frequency characteristics of the speaker are flat. , the distortion rate is reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a fiberboard used in the speaker box of the present invention, and FIGS. 2 and 3 show the relationship between the amount of sizing agent added and the flexural modulus of the material used in the speaker box of the present invention, respectively. FIG. 4, a diagram showing the relationship, is a perspective view of a speaker box in an embodiment of the present invention. 1...Flat plate, 2...Corrugated plate.

Claims (1)

[Claims] 1. A speaker box made of wood pulp as the main raw material, and a corrugated board made by processing thermoformed fiberboard into a corrugated cardboard shape by adding 2 to 4% of a thermosetting resin as a sizing agent to the raw material.