JPS6220760B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for manufacturing a bimorph piezoelectric pickup element that converts mechanical vibrations such as knock vibrations of internal combustion engines and string vibrations of electric stringed instruments into electrical signals. Regarding.

[Prior Art] In general, piezoelectric pickup elements have high mechanical strength so that they can sufficiently withstand large mechanical vibrations such as knock vibrations of internal combustion engines and string vibrations of electric stringed instruments, and can reliably generate electrical signals. It is composed of a piezoelectric composite.

In other words, piezoelectric pick-up elements are made of a piezoelectric composite made by mixing piezoelectric ceramic powder such as lead zirconate titanate in rubber such as synthetic rubber with an appropriate vulcanizing agent, and then molded into a sheet and vulcanized. After laminating two piezoelectric layers via electrode layers made of thin metal plates and fixing them together with adhesive,
The piezoelectric layer is polarized to impart piezoelectricity.

[Problems to be Solved by the Invention] However, in the conventional piezoelectric pick-up element having the above structure, the piezoelectric layer and the electrode are bonded using an adhesive, which makes the bonding process troublesome. However, it also had the disadvantage of poor productivity due to the need for strict management of adhesive storage.

The present invention eliminates these drawbacks, eliminates the use of adhesives that are troublesome and have poor workability, and makes it possible to mold a large number of piezoelectric pick-up elements at once. The purpose is to provide

[Means for Solving the Problems] The method for manufacturing a bimorph piezoelectric pick-up element of the present invention comprises two sheets molded from a piezoelectric composite made of a piezoelectric ceramic powder mixed in rubber with a sulfurizing agent. a step of obtaining a laminate from a piezoelectric layer and a large number of groups of electrode layers of a predetermined shape sequentially arranged between the piezoelectric layers, and a step of bonding the laminate together under vulcanization treatment of the piezoelectric layer. The gist of the method is to include a step of polarizing the piezoelectric layer, and a step of dividing the laminate into a large number of pieces with each electrode layer as one unit.

[Functions and Effects of the Invention] The manufacturing process of the bimorph piezoelectric pickup element of the present invention has the following functions and effects based on the above structure.

Two piezoelectric layers are formed into sheets from a piezoelectric composite made by mixing piezoelectric ceramic powder in rubber with a sulfurizing agent, and a large number of electrode layers of a predetermined shape are sequentially arranged between the piezoelectric layers. A laminate is made, the laminate is bonded together under vulcanization treatment of the piezoelectric layer, the piezoelectric layer is subjected to polarization treatment, and the laminate is divided into a large number of pieces with each electrode layer as one unit. Therefore, the use of adhesives that are troublesome and have poor workability can be omitted, and a large number of piezoelectric pickup elements can be molded at once, and mass production costs can be reduced.

[Example] Next, a method for manufacturing a bimorph piezoelectric pickup element of the present invention will be described with reference to examples shown in the drawings.

1 to 4 show a first embodiment of the invention.

100 parts by weight of lead zirconate titanate powder as piezoelectric ceramic powder, 12 to 200 parts by weight of a rubber raw material of synthetic rubber such as fluorine rubber, silicone rubber, or natural rubber, corresponding to the amount of rubber raw materials. Sulfurizing agent 0.1~
A piezoelectric composite is prepared by thoroughly kneading the mixture with 10 parts by weight using a roll machine or the like, and then molding it into two piezoelectric sheets 11 and 12, which are two piezoelectric layers having a wide area, using a cold press or the like.

Next, as shown in FIGS. 1 to 3, a lead wire connection terminal 21a is inserted between the piezoelectric sheets 11 and 12.
A large number of ring-shaped electrode layers 21, 22, 23 made of beryllium copper plates having 22a, 23a, 24a,
A laminate 3 is made by arranging 24 groups.

Next, the laminate 3 was heated at 200°C under a pressure of 15Kg/cm ² .
The electrode layers 21, 22, 23,
24, and electrode plates or foils 41 and 4 disposed in contact with the upper and lower surfaces of the material of the constant piezoelectric pickup element.
Polarization treatment is performed for 30 minutes at a polarization electric field of 150 KV/cm between 2 and 2. In addition, if necessary, an electrode plate or foil 41,
42 is also subjected to simultaneous vulcanization treatment to form each electrode layer 21, 22,
Similar to 23 and 24, they may be combined together. Then, the laminate 3 is formed by press molding each electrode layer 21, 22, 23, 24 as a unit, as shown by the dashed line in FIGS. 1 and 2.
By punching out rings having the same shape as 3 and 24, a large number of ring-shaped piezoelectric pickup elements can be obtained at once as shown in Figure 5. 6 and 7 show a second embodiment of the present invention, in which a large number of plate-shaped electrode layers 6 are used in place of the ring-shaped electrode layers 21, 22, 23, 24, and these are spread over a wide area. A piezoelectric sheet 5 which is two piezoelectric layers having an area
The stacked layers arranged in parallel between each other are integrated through the same manufacturing process as in the first embodiment, and this is shown in Fig. 6.
The plate-shaped piezoelectric pickup element shown in FIG. 7 can be mass-produced by cutting each electrode layer 6 into a plate having the same shape as each electrode layer 6 by press molding as a unit, as shown by the dotted chain line.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a first embodiment of the manufacturing process of a bimorph piezoelectric pickup device according to the present invention, and FIG. 2 is a front view showing a first embodiment of the manufacturing process of a bimorph piezoelectric pickup device according to the present invention. 3 is another side sectional view showing the first embodiment of the manufacturing process of the bimorph piezoelectric pickup device according to the present invention, and FIG. 4 is a side sectional view showing the bimorph piezoelectric pickup device according to the present invention. Another side cross-sectional view showing the first embodiment of the manufacturing process, FIG. 5 is a side cross-sectional view of the ring-shaped piezoelectric pickup element obtained by the manufacturing process of the first example, and FIG. 6 is a side cross-sectional view of the bimorph according to the present invention. FIG. 7 is a front view showing a second embodiment of the manufacturing process of a piezoelectric pickup element, and FIG. 7 is a front view showing a plate-shaped pickup element obtained from the second embodiment. In the figure, 3... laminate, 5, 11, 12... piezoelectric sheet, 6, 21, 22, 23, 24... electrode layer.

Claims (1)

[Scope of Claims] 1. Two piezoelectric layers molded into a sheet from a piezoelectric composite made of a piezoelectric ceramic powder mixed with a sulfurizing agent in rubber, and a predetermined shape sequentially arranged between the piezoelectric layers. a step of obtaining a laminate from a large number of electrode layer groups, a step of bonding the laminate together under vulcanization treatment of the piezoelectric layer, a step of polarizing the piezoelectric layer, and a step of attaching the laminate to each electrode. 1. A method for manufacturing a bimorph piezoelectric pick-up element, comprising a press molding step of dividing each layer into multiple pieces. 2. The method of manufacturing a bimorph piezoelectric pickup element according to claim 1, wherein the electrode layer has a ring shape, and the laminate has the same divided shape. 3. The method of manufacturing a bimorph piezoelectric pickup element according to claim 1, wherein the electrode layer has a plate shape, and the laminate has the same divided shape as the electrode layer.