JPS6053880B2 - Manufacturing method of piezoelectric transducer for electric stringed instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a piezoelectric transducer for an electric stringed instrument that converts string vibrations into electrical signals.

Figure 1 shows a piezoelectric transducer used in an electric piano.
A polymeric piezoelectric layer 2 and an outer electrode layer 3 are sequentially coated around the outer periphery of a conductive core 1 serving as a center electrode, and this is made of thermoplastic resin and is formed into a long and flat shape by extrusion molding, injection molding, etc. It has an aspect in which it is embedded inside the outer skin material 4.

When such a piezoelectric transducer is used, it is curved with a desired curvature as shown by the dotted line, but the bending operation is extremely difficult because the width is sufficiently large compared to the thickness.

The present invention has been made in view of the above-mentioned circumstances, and provides a method for easily manufacturing a piezoelectric transducer that is long, flat, and curved with a desired curvature.

Examples will be described below. In FIG. 2, a polymeric piezoelectric layer 12 made of, for example, a mixture of 1 part by weight of chloroprene rubber and 800 parts by weight of lead titanate is placed around the outer periphery of a stainless steel stranded wire 11 of 7 O, lwgAφ as a center electrode. .6- is coated, and its outer periphery is further covered with a stainless steel knitted body 13 as an outer electrode, and the outer periphery is further covered with a urethane resin outer skin material 14 having a rectangular cross section of 3-5mm vertically and 5wn horizontally, Then the center electrode 11 and the outer electrode 13
A piezoelectric cable 10 is shown which has been polarized by applying a predetermined DC voltage therebetween.

This piezoelectric cable 10 can be freely bent and deformed as shown by the dotted line. The piezoelectric cable obtained as described above was cut into a length of 300 TfgR to prepare three pieces, and these were cut into a lower plate M that constitutes a mold M as shown in Fig. 3.
The cavity of the intermediate plate (3007
$11 x 157rfmW x 900-''
At the same time, the upper and lower plates M, , Mo and the intermediate plate M2 are fixed together using tightening fittings such as bolts and nuts M5 that pass through the upper and lower plates M, Mo, and the intermediate plate M2 at appropriate locations on the outer periphery, and at the same time, the inside of the cavity c is A constant pressing force is applied to the plurality of piezoelectric cables 10 groups arranged in a row.

Next, the mold M in which a plurality of piezoelectric cables 10 are set under constant pressure as described above is held in a 17-bottom heating furnace, and after cooling, the molded product (piezoelectric transducer P ).

As shown in FIG. 4, the molded product (piezoelectric transducer P) taken out from the mold has a shape in which the contact surfaces of the piezoelectric cables 10 are fused to each other and integrated, and are long, flat, and curved with a desired curvature. was kept.

Although the above embodiment shows an embodiment using a plurality of piezoelectric cables, a combination of at least one piezoelectric cable and a non-piezoelectric cable with a square cross section made only of thermoplastic resin may be used. May be used.

As described above, according to the manufacturing method of the present invention, it is possible to easily obtain a long, flat piezoelectric transducer with a desired curvature, which has the effect of simplifying assembly especially when used in an electric piano.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a piezoelectric transducer according to a conventional example, FIG. 2 is a perspective view of a piezoelectric cable used in the present invention, FIG. 3A is a side sectional view showing an embodiment of the present invention, and FIG. 4 shows an exploded perspective view thereof, and FIG. 4 shows a perspective view of a piezoelectric transducer obtained by the manufacturing method of the present invention. 10... Piezoelectric cable, 11... Conductive core, 12... Polymer piezoelectric layer, 13...
・Outer electrode layer, 14...Outer skin material, P...
・Piezoelectric transducer, M...Mold, C...Cavity.

Claims (1)

[Claims] 1. A flexible piezoelectric cable in which the outer periphery of a conductive core serving as a center electrode is coated with a polymeric piezoelectric layer and an outer electrode layer, respectively, and an outer skin material made of thermoplastic resin having a square outer circumferential cross section. A plurality of piezoelectric cables or a combination of at least one piezoelectric cable and a flexible non-piezoelectric cable made of thermoplastic resin and having a rectangular cross section are placed in the mold cavity in parallel and with a desired curvature. A method for manufacturing a piezoelectric transducer for an electric stringed instrument, which comprises arranging a piezoelectric transducer in a curved manner and integrally molding the piezoelectric transducer into a long, flat shape with a desired curvature by applying pressure and heating.