JPS606001B2 - Head shell for pickup arm and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a head shell for a pickup arm and a method for manufacturing the same.

Conventionally, this gutter head shell consists of a horizontal part 1 for attaching a cartridge and a vertical part 2 for attaching a connector formed at the rear end, as shown in FIG. , screws, adhesive, etc., and A- in Fig. 1.
The shapes seen in the cross section along the A line can be roughly classified as shown in Figure 2 A.
．． The shapes are as shown in B and C.

In terms of materials and molding means, they are made by forging, die-casting, and molding from light alloys such as aluminum, magnesium, and ceramics, or by molding plastics.

- In general, the characteristics required of this type of head shell include being lightweight, being resistant to bending and torsion, and having a high vibration damping rate. However, although the subordinate head shell is fairly light and heavy, it lacks bending and torsion strength, and as a result, it is difficult to generate partial resonance as shown by r in the frequency characteristic diagram in Figure 3. As a result, the sound quality deteriorates.

This is caused by the lack of strength of the head shell when viewed from connector 3. Head shells using carbon fiber have been proposed to improve the above-mentioned drawbacks, but they are either made by cutting carbon fiber into short pieces or mixing it with plastic and molding it, or by mixing long fibers into plastic. Even with the materials used, it was difficult to mold them into the cross-sectional shapes shown in FIGS. 2A and 2B, and they were only in the shape of a flat plate as shown in FIG. 2C.

Therefore, in the former case, the mechanical strength, especially the flexural modulus, is significantly reduced by cutting the fiber to short lengths, and although it is useful for reinforcing plastic, it is not satisfactory as a head seal. In addition, in the latter case, the first
Since a hole is required to attach the connector to the vertical part 2 shown in the figure, the mechanical strength (bending rigidity "torsional rigidity") between the head shell and the connector cannot be increased, and a sufficient effect cannot be obtained. Conventional head shells that utilize carbon fiber have the disadvantage that the excellent properties of carbon fiber, such as light weight and high flexural modulus, are not fully utilized.

The present invention solves the above-mentioned conventional drawbacks, satisfies the characteristics required of a head shell, and provides a head shell that can prevent the occurrence of partial resonance in frequency characteristics and thereby improve sound quality. With the goal. Another object of the present invention is to provide a method for easily manufacturing the above-mentioned excellent head shell.

Embodiments of the present invention will be described below based on the drawings from FIG. 4 onwards. A cylindrical body 4 is obtained by winding a carbon fiber prepreg sheet around a winding shaft (not shown).

In this case, in the case shown in FIG. 4, the fibers are laminated in different directions, with the first layer 5 oriented in the wisteria line direction, the second layer 6 spirally wound around its outer periphery, and the second layer 6 spirally wound around its outer periphery. It consists of a third layer 7 spirally wound around the outer periphery in the opposite direction to the second layer 6, and a fourth layer 8 formed linearly on the same outer periphery as the first layer. By laminating Buripreg sheets as shown in Fig. 4, the linearity of the fibers can be effectively utilized and the bending and torsional strength can be further increased.

The one shown in FIG. 5 is made by knitting carbon fibers into a pipe shape, and because the straightness of the fibers is sacrificed to some extent, it is slightly inferior in strength to the one shown in FIG. 4.

The above-mentioned cylindrical body does not have to be cylindrical and may be prismatic, but cylindrical is preferable from the viewpoint of molding and the shape of the connector.

The cylindrical body 4 obtained as described above is impregnated with an epoxy resin or other thermosetting resin by vacuum immersion method or other means, and a part of the cylindrical body is shown in FIG. 6 by heating and pressure molding. A flat part 9 for attaching the cartridge is formed by crushing it as shown in FIG.

In this case, since the cartridge is attached to the lower surface of the flat portion 9, it is desirable that the flat portion 9 be formed so as to be unevenly distributed in the outer circumferential direction than the axis 48 of the cylindrical body 4. As shown in FIG.
As shown in the figure, terminal insertion holes 13, 13, etc. are cut into the crushed wall portion 12 to form a head shell. Incidentally, as shown in FIG. 8, the connector 3 is attached to the entrance at the rear of the head shell.
14 is a mounting screw.

As mentioned above, carbon fiber was used in the examples, but it is not necessarily limited to this, and carbon fibers that can be used in FRP (fiber reinforced plastic) such as boron fiber and glass fiber and have low specific gravity and high elasticity are also used. In addition, by forming the knot-shaped body 4 into a long length and cutting it into a predetermined length, a large number of uniform head shells can be obtained. It is also possible to provide an offset angle to the angle.

In addition, in the laminated cylindrical body shown in FIG. 4, each layer may be formed of different fibers to take advantage of the characteristics of each fiber. According to the head shell for a pickup arm of the present invention, it is molded from a fiber having low specific gravity and high elasticity, and the flat part for cartridge attachment is formed by pressing a part of the cylindrical body, and the connector is Since it is attached to the entrance of the rear engine, the material is lightweight and mechanically strong, and the flat part is integrally molded from the rear cylindrical part, so it is like a pipe. Since it can be thought of as an extension of , it is possible to increase bending rigidity and torsional rigidity, prevent the occurrence of partial resonance, and improve sound quality.

Furthermore, since at least one layer of the cylindrical body is laminated so that the fiber directions are different, the linearity of the fibers can be effectively utilized.
Since one layer has a spiral shape, bending and torsional strength can be further increased.

In addition, since the connector is attached to the rear end entrance, there is no need for large holes for attachment as in the past, so mechanical strength can be maintained and assembly is easy. .

Regarding the method for manufacturing the head shell of the present invention, it is extremely easy to produce a uniform product because it only involves crushing a part of the cylindrical body molded from carbon fiber or the like to form a flat part for attaching the cartridge. There are features that can be used.

[Brief explanation of the drawing]

Figures 1 and 2 show a conventional head shell for a pickup arm. Figure 1 is a sectional view, and Figure 2 is a sectional view taken along line A-A in Figure 1. FIGS. 4 to 8 show examples of the present invention, FIGS. 4 and 5 are perspective views of the cylindrical body, and FIG. FIG. 7 is an elevated perspective view, and FIG. 8 is a line sectional view showing the state in which the connector is attached. 3...Connector, 4..., Cylindrical body, 4a...Cylinder Body's mari line, 5
~8... Each layer, 9... Flat part, 10... Shell body, 11... Cartridge mounting hole, 12... Wall part, 13... Terminal insertion hole, 14... Mounting screw. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Scope of Claims] 1. A laminate in which fibers having low specific gravity and high elasticity, such as carbon fibers, are impregnated with a thermosetting resin, and at least one layer is spirally wound so that the fiber directions are different. By crushing a part of the cylindrical body under heat and pressure, the flat part is formed so that it is unevenly distributed in the outer circumferential direction rather than the axis of the cylindrical body, and the flat part is the mounting part of the cartridge. A head shell for a pick-up arm, characterized in that the rear end opening is cut so as to serve as a mounting part for a connector to the pick-up arm. 2. A cylindrical body is formed by laminating at least one layer of fibers having low specific gravity and high elasticity such as carbon fibers so that the fiber directions are different, and the cylindrical body is impregnated with a thermosetting synthetic resin and heated. After crushing a part of the cylindrical body by pressure molding so that the flat part is biased in the outer circumferential direction rather than the axis of the cylindrical body, the flat part becomes a mounting part for the cartridge. A method for manufacturing a head shell for a pick-up arm, characterized in that the end opening is cut so as to serve as a mounting part for a connector to the pick-up arm.