JPS6029210B2 - Capacitor manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved manufacturing method of a capacitor using a ceramic sheet as a transfer body, applying an electrode to the surface of the ceramic sheet, winding it, and firing it. This is an attempt to improve the attachment strength of the cable wire, which has been a problem during assembly.

As shown in FIGS. 1 and 2, conventional capacitors of this type include a ceramic sheet 1 having internal electrodes 3 and 4 provided on the surface thereof, except for the electrodes near one side edge E, E2, respectively. . Electrode 5
, 6, respectively, were attached to the nail head lead wires 7 and 8 with solder, etc.

A is the winding core. However, although the tips of the lead wires 7 and 8 are formed into nail head leads, they are only attached with solder, etc., which creates a large stress, which means that when automatically assembled into a printed circuit board, etc. The force against the applied external force was 4.5%, which was not desirable.

Also, conventionally, a cap terminal 9 has lead wires 7 and 8 attached to both end surfaces of the wound body M as shown in the third figure.
, 10 were press-fitted and fixed in some cases. However, in those that are press-fitted using these cap terminals 9 and 10,
The dimensional accuracy is particularly strict, and the winding body M may break during press-fitting, resulting in poor moisture resistance, and the internal electrode 3
, 4 are exposed. Furthermore, in the case of this press-fitting method, in order to facilitate the press-fitting or to achieve dimensional accuracy, it is necessary to polish the twill part or the circumferential surface of the wound body M, which only requires more time and effort in manufacturing. Moreover, it is necessary to provide an additional layer on the outermost layer in advance to prevent the internal electrodes 3 and 4 from being exposed during polishing, which is not suitable for miniaturization of components. The present invention has been made in view of the above-mentioned conventional drawbacks, and involves inserting a part of the lead wire from both end faces of the winding core of the winding body toward the center in the longitudinal direction, and when firing the winding body. It is an object of the present invention to provide a method for manufacturing a capacitor whose main gist is to shrink the winding core and fix the lead wire.

That is, in the manufacturing method of the present invention, first, as shown in the first figure above, an unfired mother Ti0 is prepared, in which internal electrodes 3 and 4 are respectively provided on the surface except for the vicinity of one side edge E, , E2.
A plurality of ceramic sheets 1 and 2 of 3 series or Ti02 series are stacked one on top of the other so that the side ends to which the electrodes 3 and 4 are not provided alternate, and are also wound around an unfired ceramic winding core A. A rotating body M is formed.

In this case, the internal electrodes 3 and 4 are Pt, Pd, Ag-Pd, Ni, Pt, Pd, Ag-Pd, Ni, etc. because they are fired at the same time as the ceramic.
High melting point metals such as Fe, W, and Mo are used. Further, the number of ceramic sheets 1 and 2 is not limited to two, but three or more may be stacked. That is, the internal electrodes 3 and 4 are alternately led out to both end surfaces S, S2 of the wound body M formed in this manner. Next, as shown in FIG.
Through holes 11 and 12 are formed from the center toward the center in the longitudinal direction,
Parts of lead wires 13 and 14, which are made of a material that does not melt at the degree of firing of the ceramic and are not electrically conductive to each other, are inserted into the through holes 11 and 12, respectively.
In this case, the through holes 11 and 12 may be blind holes or may be drilled in advance in the winding core A before forming the wound body M, and the means for forming them may also be a drill or the like. However, the lead wires 13 and 14 may be formed at the same time as the molding process, or the lead wires 13 and 14 may be embedded in advance. Further, the through holes 11 and 12 may be formed by passing through both ends of the winding core A. The material of the lead wires 13 and 14 may be the same as that of the internal electrodes 3 and 4, but from the viewpoint of cost, Ni, Fe, etc. are preferable. Next, the internal electrodes 3, 4 lead wires 13, 14 led out to both end surfaces are conductively connected to both end surfaces S, S2 of the wound body M to which the lead wires 13, 14 are attached. The external electrodes 15 and 16 are provided to provide the external electrodes 15 and 16. This part electrode 15,1
The same material as the internal electrodes 3 and 4 is used for the material of the electrode 6. Finally, the entire structure thus formed is simultaneously fired to obtain a capacitor. That is, in the present invention, the entire winding is conducted with the lead wires 13 and 14 attached to the winding core A,
By utilizing the shrinkage of the unfired ceramic sheets 1, 2 and the winding core A due to firing, the winding body M is formed with good clogging and the lead wires 13, 14 are firmly fixed.

In this case, due to the shrinkage of this ceramic, the external electrode 1
5, 16 If there is a concern that the conductive connection with the lead wires 13, 14 may be broken, attach an auxiliary electrode in advance near the base of the attachment part of the lead wires 13, 14 to the through holes 11, 12. Just let it happen. FIG. 5 shows another example of the structure of the capacitor manufactured in this way, in which the wound body M
is formed into an elliptical plate shape, and protrusions 13a, 14a are provided at one ends of lead wires 13, 14 attached to the winding core A, and these protrusions 13a, 14a are used as attachment parts.

FIG. 6 shows still another example of the configuration, in which the lead wire 1
There are bulges 13b and 1 in the portions inserted into the winding cores A of 3 and 14.
4b is provided, and these bulging portions 13b and 14b are completely wrapped around the winding core A.
The lead wires 13, 12 are inserted into the through holes 11, 12 of the
14 is inserted, and the lead wires 13 and 14 are prevented from coming off by shrinkage of the ceramic.

Next, another example of the manufacturing method of the present invention will be described.

Note that the following explanation will be given only to the parts that are different from the above-mentioned embodiments. When winding the ceramic sheets 1 and 2 provided with the electrodes 3 and 4, a winding core made of an appropriate material (metal, etc.) is used, and after winding, the winding core is removed and the rolled body M is wound. A through hole is formed, and a newly unfired or temporarily fired ceramic rod is inserted as a winding core A into the through hole.

This winding core A also has a through hole 11 for inserting the lead wires 13 and 14,
Needless to say, 12 holes are provided. In this case, if the outer diameter of the winding core A is appropriately selected in light of its material, the material of the winding body M, etc., the firmness of the winding body M during the final firing can be further improved. Furthermore, to show another embodiment of the method of the present invention, after winding the ceramic sheets 1 and 2, the winding core is removed to form a through hole, and a part of the lead wires 13 and 14 are inserted in advance into the through hole. A ceramic rod, which is embedded and fixed at both ends, may be inserted as the winding core A.

The core A in this case may be unfired, or may be pre-fired or fired. The manufacturing method of the capacitor of the present invention has the above-mentioned configuration, and as a result, not only the overall compaction is improved, but also the adhesion strength of the lead wires is improved to the extent that there is no problem at all compared to the conventional method. can be done.

For example, if the lead wire of a conventional nail head is made of Fe and attached with solder, a tensile strength of only about 2k9 can be obtained, whereas the one obtained by the present invention has a tensile strength of only about 2k9. None of them came off even with 20k9, and as a result of further tensile tests, it was confirmed that all of them had strength until the lead wires broke. In the present invention, if noble metal materials are used as the material for each electrode and lead wire, firing in air is possible, but if base metals are used, these will oxidize during firing in air, so each electrode and lead wire can be fired in air. It no longer has the function of

Therefore, in this case, firing must be carried out in a neutral or reducing atmosphere. Furthermore, in this case, it is necessary to use a non-reducible ceramic material. In addition, although not stated in each of the above examples,
If a slurry made of ceramic powder suspended in varnish is used as an exterior material for the entire product before firing the entire product, there is no need to apply a new exterior material later, which is convenient. In this case, the material of the ceramic powder is preferably the same as that of the ceramic sheet from various points of view. Further, the capacitor obtained according to the present invention can be applied not only as an ordinary fixed capacitor but also as a feedthrough capacitor. In this case, it goes without saying that the lead wires fixed to the winding core may be connected to form a through terminal. As described above, the present invention has the effect that by firing the ceramic sheet, the winding core, the internal electrodes, the external electrodes, and the lead wires at the same time, the overall firing is good and the adhesion of the lead wires is strong. .

Therefore, when used for automatic assembly into a printed circuit board or the like, there is no need to worry even if some external force is applied to the lead wire. In addition, in the present invention, since it is only necessary to attach the lead wire to the winding core and fire it, manufacturing is extremely simple, and the disadvantages that arise when press-fitting the secondary cap terminal, such as cracks and chips in the winding body, can be avoided. , increasing the size of parts, and complicated polishing of the wound body can all be eliminated.

[Brief explanation of the drawing]

Fig. 1 is a state diagram of the wound body, Figs. 2 and 3 are partial side sectional views of a conventional capacitor, Fig. 4 is a side sectional view of a capacitor obtained by the present invention, and Figs. FIG. 6 is an exploded perspective view and a side sectional view showing another example of the shape. 1, 2... Ceramic sheet, 3, 4...
Internal electrode, M...Wound body, A...Ceramic winding core, 11, 12...Through hole, 13, 14
...Lead wire, 15,16...External electrode. Tsutomu's drawings, many Z drawings, Tsutomu's drawings, Tsutomu's illustrations, and the remaining 5 drawings.

Claims (1)

[Scope of Claims] 1. A plurality of unfired ceramic sheets each having internal electrodes provided on the surface except for the vicinity of one side edge are stacked one on top of the other so that the side edges without electrodes alternate, Similarly, a wound body is formed by winding around an unfired ceramic winding core, and holes formed from both end faces of the winding core toward the center in the longitudinal direction are filled with molten material at the firing temperature of the ceramic. Insert a part of a lead wire made of a material that does not cause the winding, and apply external electrodes to the entire surface of both end surfaces of the wound body, and each external electrode leads out to both end surfaces of the wound body. A method for manufacturing a capacitor, comprising the steps of electrically connecting the internal electrodes inserted into the core and the lead wires inserted into the through holes of the winding core, and then firing the whole at the same time. 2 After a plurality of unfired ceramic sheets with internal electrodes attached to the surface except for the vicinity of one side edge are stacked one on top of the other so that the side edges without electrodes alternate and are wound around a core. This winding core is removed to form a through hole, and a similarly unfired or pre-fired ceramic rod is inserted as a winding core into this through hole to form a wound body, and both end surfaces of the winding core of this ceramic rod are inserted. A portion of a lead wire made of a material that does not melt at the firing temperature of the ceramic is inserted into a through hole drilled toward the center in the longitudinal direction, and the entire surface of both end surfaces of the wound body is inserted. each of which is provided with an external electrode, and each external electrode conductively connects the internal electrode led out to both end surfaces of the wound body and the lead wire inserted into the through hole of the winding core, A method for producing a capacitor, which is characterized in that the whole is then fired simultaneously. 3 After a plurality of unfired ceramic sheets with internal electrodes attached to the surface except for the vicinity of one side edge are stacked one on top of the other so that the side edges without electrodes alternate and are wound around a core. This winding core is removed to form a through hole, and a ceramic rod is used as the winding core, with part of the lead wire, which does not melt at the ceramic firing temperature, embedded and fixed in advance at both ends of the through hole. The wound body is inserted through the wound body to form a wound body, and external electrodes are applied to the entire surfaces of both end surfaces of the wound body. A method for manufacturing a capacitor, which comprises making a conductive connection between lead wires fixed to the core, and then firing the whole at the same time.