JPH05241569A - Sound plate - Google Patents

Abstract

PURPOSE:To improve a vibration characteristic and to facilitate the production by integratedly molding a plate material made of a fiber reinforced plastic with cavities in the same sectional shape as a sound plate. CONSTITUTION:The plate 5 is produced by a drawing molding method. That is, reinforcing fibers are aligned so that the directions of the fibers are arranged in one direction and are immersed in the liquid of a thermosetting resin to obtain reinforcing fibers impregnated with the resin. Then, reinforcing fibers impregnated with the resin are oriented in such a manner that the directions of fibers are in one direction to be a molding precursor. The molding precursor is introduced to a cavity forming die which is cylindrical and slender in the same direction along the orientation direction of the fibers and cavities 6 are formed inside the molding precursor along the molding direction by the cavity forming die. Then the molding precursor is introduced to a die for regulating the outer shape with the same sectional shape as the sound plate 4 and immediately after pulling out from the mold outlet of the die, the molding precursor is heated and cured by a heating die provided successively on the molding die to form the plate 5 with the same sectional shape as the sound plate 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound plate for a percussion instrument, and a fiber reinforced resin plate material in which reinforcing fibers are oriented in one direction and a cavity extending in the same direction as the direction of the reinforcing fibers is formed. By integrally molding the sound plate into the same cross-sectional shape, the homogeneity of the sound plate is improved, the vibration characteristics are improved, and the manufacturing work is facilitated.

[0002]

2. Description of the Related Art In recent years, as sound plates for percussion instruments such as xylophone and marimba, various fiber reinforced resin plates have been proposed in place of wooden sound plates whose tone and scale are easily changed depending on weather conditions. .. An example of such a soundboard made of reinforced fiber resin is disclosed in Japanese Patent Laid-Open No. 63-163397. Such a sound plate is formed by forming a large number of cavities extending in the same direction as the orientation direction of the reinforcing fibers in the fiber reinforced resin, and has a good sound spread characteristic of the fiber reinforced resin sound plate and a wooden sound plate. It is an excellent sound board that has the soft and warm tone peculiar to. As shown in FIG. 3, this sound plate was formed by stacking fiber-reinforced resin plate materials having cavities, adhering and fixing these plate materials, and laminating a plurality of plate materials.

[0003]

Since the conventional sound plate has the above-described structure, it takes time to manufacture the sound plate.
There is a drawback that the manufacturing cost increases. Also, if there is an incompletely bonded and fixed part, the vibration characteristics of the sound plate become abnormal.On the other hand, if the adhesive layer becomes thick, the sound plate becomes inhomogeneous and the vibration characteristics vary. There was also a problem that it was likely to occur. The present invention has been made in view of such circumstances, and by integrally molding a fiber-reinforced resin plate material with a cavity with the same cross-sectional shape as the sound plate, while improving the vibration characteristics, the manufacturing work The purpose is to facilitate.

[0004]

In order to solve the above problems, in the invention according to claim 1, a plate material integrally formed of unidirectionally oriented reinforcing fibers, and the reinforcing fibers. And a cavity extending in the orientation direction of. The invention according to claim 2 is characterized in that the cavity is formed by drawing.

[0005]

Since it is integrally formed with the same cross-sectional shape as the sound plate, it is a homogeneous material with no joint surface.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a sound plate according to the present invention. A sound plate 4 shown in FIG. 1 is an integrally molded plate material made of fiber reinforced resin (hereinafter abbreviated as plate material) 5. It consists of The plate member 5 is formed by orienting reinforcing fibers in a resin matrix in one direction. As the reinforcing fibers, long fibers such as glass fibers, carbon fibers and aramid fibers are used, and glass fibers and highly elastic carbon fibers are particularly preferable. Further, short fibers such as silicon carbide and boron nitride may be used in combination.

Examples of the resin include thermosetting resins such as epoxy resin, unsaturated polyester resin, vinyl ester resin, and phenol resin. Considering the adhesiveness between the reinforcing fiber and the resin, for example, the above-mentioned resin is used. If the reinforcing fiber is glass fiber, a combination of unsaturated polyester resin or vinyl ester resin is preferable, and if it is carbon fiber, epoxy resin is preferably used in combination. The amount of the reinforcing fiber is usually 30-
70% by volume, preferably 50-60% by volume. Three
If it is less than 0% by volume, mechanical reinforcement of the resin is not sufficient and only a reinforced resin having a low Young's modulus can be obtained. If it exceeds 70% by volume, wetting of the fiber and the resin deteriorates and a homogeneous reinforced resin is obtained. Can't get Then, the compounding amount and the type thereof are appropriately selected so that the Young's modulus of the composition including the resin and the reinforcing fiber is 2000 (Kg / square millimeter) or more.

The plate material 5 has a proper number of cavities 6 formed therein. The cavity 6 is formed so that its direction is the same as the orientation direction of the reinforcing fibers, and in this embodiment, it is formed parallel to the longitudinal direction of the sound plate 4. The cross-sectional shape of this cavity 6 (the shape of the cross section orthogonal to the longitudinal direction of the plate material 5) may be any shape such as a square shape other than the round shape shown in FIG. Further, the cross-sectional area of the cavity may be arbitrary, and different shapes and different cross-sectional areas may be mixed. And this cavity 6
The total cross-sectional area of the plate material 5 is determined within a range of 5 to 60% with respect to the cross-sectional area of the plate material 5 at the same cross section, and the cross-sectional area of the cavity 6 is determined according to the characteristics required for the sound plate 4. And the number of them and the like are adjusted. When the ratio of the cross-sectional areas is less than 5%, the wood tone is not imparted to the tone color of the sound plate 4, and when it exceeds 60%, the problem that the sound spread is deteriorated occurs. 4, 5 and 6 show an example of the arrangement position of the cavities 6 and an example of the open area ratio. These cavities are placed away from the striking surface (top surface),
Compensates for strength against hits. Further, different shapes of the cavities may be combined, and the open area ratio, which is the ratio of the cavity cross-sectional area to the sound plate cross-sectional area, is, for example, 14.5 to 26.9% in the example of FIG. 21.2% to 2 in the example
It is 6.0%, and in the example of FIG. 6, it is about 19.4% to 29.1%.

Next, an example of a method of manufacturing the sound plate 4 having such a structure will be described. First, the plate material 5 is manufactured by the pultrusion molding method. That is, for example, reinforcing fibers such as glass rovings are aligned so that the fiber direction is unidirectional. Then, the reinforcing fibers aligned in one direction are immersed in a thermosetting resin liquid such as an uncured unsaturated polyester resin to obtain a reinforcing fiber impregnated with the resin. Here, a peroxide curing agent such as benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, etc. (resin 100
0.5 to 1.5 parts by weight relative to 100 parts by weight), for example, a release agent such as zinc stearate (1 to 100 parts by weight of resin)
3 parts by weight), for example, an additive such as a lubricant such as calcium carbonate (5 to 50 parts by weight based on 100 parts by weight of the resin) is preferably mixed in advance.

Next, the resin-impregnated reinforcing fiber is oriented so that the direction of the fiber is unidirectional, and this is used as a molding precursor. Next, the molding precursor is guided to the elongated columnar cavity forming die in the same direction along the fiber orientation direction, and the cavity forming die is used to form a cavity 6 inside the molding precursor along the molding direction. To form. Next, this molding precursor is guided to an outer shape regulating die having the same cross-sectional shape as the sound plate 4, and is pulled out to the outside from the molding outlet of this die, and then immediately heat-cured by a heating die connected to the die. 2 to form a plate member 5 having the same sectional shape as that of the sound plate 4. Here, the sum of the cross-sectional areas of the plate material 5 of the cavity 6 is in the range of 5 to 60% of the cross-sectional area of the plate material 5 in the cross section in the same direction as described above, but easy molding is performed within this range. It is desirable to make the cross-sectional area of one cavity 6 as large as possible in consideration of the property.

Further, the cavity 6 can be mechanically formed inside the plate member 5 having the same cross-sectional shape as the sound plate 4 along the longitudinal direction thereof by using a borer or the like. Next, the other side surface of the plate material 5 opposite to the one side surface 3 is subjected to a scooping process for tuning, and then a post-process such as a coating process is applied to the whole surface of the sound plate 4 as shown in FIG. To get The sound plate 4 thus obtained is a fiber-reinforced resin in which the cavities 6 extending in the same direction as the orientation direction of the reinforcing fibers are appropriately formed. It has both the good sound spread characteristic of a resin sound plate and the soft, woody sound tone unique to a wooden sound plate.

[0012]

As described above, in the sound plate of the present invention, the reinforcing material is oriented in one direction, and the plate material having the cavity extending in the same direction as the orientation direction of the reinforcing fiber is formed into the same sectional shape as the sound plate. Since it is integrally molded, the following excellent effects can be obtained. First, since it is integrally formed with the same cross-sectional shape as the sound plate, it becomes a homogenous one with no joint surface, and has excellent vibration characteristics. Secondly, according to the above configuration, the cavity and the outer shape can be simultaneously formed by drawing, the sound plate can be easily processed, and the man-hours can be reduced to reduce the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a sound plate of the present invention.

FIG. 2 is a schematic configuration diagram showing a plate material used for the sound plate of the present invention.

FIG. 3 is a schematic configuration diagram showing an example of a conventional sound plate.

FIG. 4 is a cross-sectional view of another embodiment.

FIG. 5 is a cross-sectional view of another embodiment.

FIG. 6 is a cross-sectional view of another embodiment.

Claims (2)

[Claims] 1. A sound plate comprising a plate material integrally formed of reinforcing fibers oriented in one direction, and a cavity extending in the direction of orientation of the reinforcing fibers. 2. The sound plate according to claim 1, wherein the cavity is formed by pultrusion.