JPH04206913A - Manufacture of capacitor - Google Patents

Abstract

PURPOSE:To secure a sufficiently long insulation distance, even when the diameter of, a core is small or the protruding length of the core is short, by applying a metal spraying treatment for taking out an electrode to both sides of a capacitor element formed through winding and laminating a dielectric on a cylindrical core and thereafter by grinding at least the inner peripheral face of the core to remove a sprayed metal stuck to that part. CONSTITUTION:A capacitor element is obtained when a dielectric 2 is wound a required number of times on a core 1 composed of a synthetic resin cylinder, cylinder body wound by paper or film, etc. In a capacitor element C1 obtained by applying a metal spraying treatment, i.e., metallikon treatment to that capacitor element, a sprayed metal is stuck to not only the side face 21 of the dielectric 2 but also the exposed parts such as end face 11 and inner peripheral face 12 of the core 1 to form a sprayed metal layer 3. When the sprayed metal stuck to the whole of both end faces 11, 11 of this core 1 and to the both end sides of the inner peripheral face 12 of the core 1 continuing to the both end faces is removed by grinding, it is possible to obtain a capacitor C largely improved in insulating property and excellent in withstand voltage characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a capacitor having sprayed metal layers for taking out electrodes on both sides of a capacitor element.

(Prior Art) It is known to thermally spray a conductive metal on both sides of a capacitor element to form a thermally sprayed metal layer, and to use this thermally sprayed metal layer for electrode extraction.

In the manufacturing method of this type of capacitor, when the metallcon treatment is performed, as shown in FIG. 2, which may impair insulation properties and withstand voltage properties. In the figure, C represents a capacitor element.

Therefore, as disclosed in Japanese Patent Publication No. 2-3290, the applicant removed the melt 1 metal adhering to the 6 end surfaces of the winding core 1,
Tsutsumi devised a manufacturing method for Ndenza, which can improve insulation properties and withstand voltage properties. This method involves grinding the end surface 11 of the winding core of the metallicon-treated condenser element C (see FIG. 3) to remove the sprayed metal deposited on the end surface 11. As shown in FIG. 2, the capacitor manufactured by this method has a sprayed metal layer 3 on the inner circumferential surface 2, the outer circumferential surface 13, and the side surface 21 of the dielectric 2, and the end surface 11 of the core 1. does not have a sprayed metal layer, resulting in improved insulation properties and withstand voltage properties.

(Problem to be solved by the invention) However, the manufacturing method of the above capacitor is based on the research.

Since the end face 11 of the winding core 1 which has been shaved to remove the sprayed metal layer is intended to ensure insulation properties and voltage resistance characteristics, in the case of a capacitor where the diameter of the winding core 1 is small, the end face 11 of the winding core 1 is Since the creepage distance of the end face 11 of the capacitor is short, there is a problem in that it is difficult to secure sufficient insulation 11 [1], and this makes the capacitor unsuitable for manufacturing capacitors that require high withstand voltage characteristics. Furthermore, if the lateral protrusion length of the winding core 1 is shortened in order to convert the capacitor into a condenser, it may become impossible to carry out the above method due to the grinding allowance.

This invention was made to solve the above-mentioned conventional drawbacks, and its ``first purpose is to provide a sufficiently long insulation distance even when the diameter of the winding core is small or the protrusion length of the winding core is short. It is an object of the present invention to provide a method for manufacturing a capacitor that can ensure high reliability.

(Means for Solving the Problem) Therefore, the method for manufacturing a capacitor according to the first claim i8 provides a method for producing a capacitor by winding and laminating a dielectric material around a cylindrical winding core. After the metal spraying process is performed, at least the inner circumferential surface of the winding core is ground to remove the sprayed metal attached to the part.

Further, the capacitor manufacturing method according to the second aspect is characterized in that the end face as well as the inner circumferential face of the winding core is ground.

(Function) This method eliminates warping on the inner circumferential surface of the winding core by metallization treatment. Thermal sprayed metal layer formed with Ur and θ: h: iru
The formed thermal sprayed metal layer is removed.

(Example) Next, a specific example of the method for producing condensate according to the present invention will be described in detail with reference to the drawings.

A capacitor element is obtained by winding a dielectric material a required number of times around a core made of a synthetic resin cylinder, a cylinder wound with paper or film, etc., using well-known means. A metal spraying process, that is, a metallicon process is performed on such a capacitor element 7. Capacitor element C treated with metallicon
6 is the side surface 210 of the dielectric 2, as explained in FIG.
Instead, the sprayed metal adheres to exposed portions such as the end surface 11 and inner circumferential surface 12 of the winding core 1, resulting in a sprayed metal layer 3 (6). In such a capacitor element C1, the surface 11 and the inner circumferential surface 12 of the winding core 1 are ground with a culm, and the sprayed metal adhering to the ground portions is removed.

For grinding, a well-known grinding tool such as a grindstone or a cutter is used.

FIG. 1 shows a capacitor C manufactured according to the present invention, showing the entirety of both end surfaces 11, 1 of the winding core 1, and both end sides of the inner circumferential surface 12 of the winding core 1 following the end surfaces 11 and 11. This is the area where the sprayed metal was removed due to grinding.

According to experiments, in the case of the capacitor element CI explained in Fig. 3, the two electrodes are short-circuited, but in the case of the capacitor C explained in Fig. 1, the insulation characteristics are greatly improved.
It was confirmed that this capacitor has excellent withstand voltage characteristics. In addition, the capacitor C shown in Fig. 1 has significantly improved insulation characteristics, and has excellent strength 7 and withstand voltage characteristics, even compared to the capacitor explained in Fig. 2, in which only the end face 11 of the winding core 1 is ground. I was able to confirm that it was a high quality capacitor. An end surface 11 on one side Lj to the winding core 1 and an inner circumferential surface 12 on one side following it
Satisfactory values for insulation resistance and withstand voltage characteristics could be obtained even for those with rough edges. Further, substantially similar results were obtained for the case where only the inner circumferential surface I2 was ground.

If the core 1 is made of rolled paper or film, the core 1 may be impregnated with a penetrating hardening agent such as Evogishi resin, or the end surface of the core 1 may be welded prior to metallicon treatment. It is desirable to keep it.

This not only prevents the thermal sprayed metal from penetrating between the layers of the winding core 1 during the metallicon treatment and impairing the insulation properties, but also prevents the end surface 1 of the winding core 1 from being damaged.
There is an advantage that the inner circumferential surface 12 can be well ground and the sprayed metal layer can be reliably removed.

(Effects of the Invention) As described above, according to the method for manufacturing a capacitor according to the first aspect, the melt formed by the metallcon treatment. Since the l-1 metal layer is removed from at least the inner peripheral surface of the winding core, the insulation distance can be increased correspondingly to the grinding depth of the inner peripheral surface.Therefore, the insulation distance can be increased by the creepage distance of the end surface. As a result, it becomes possible to manufacture capacitors with excellent withstand voltage characteristics. This has the effect that even a capacitor with a small diameter can be provided with a sufficiently long insulation distance to provide the necessary high withstand voltage characteristics.Also, since the inner peripheral surface of the winding core is ground, the side surface of the dielectric material Another advantage is that even if the protruding width of the winding core from the winding core is small, it will not hinder the implementation of the invention.

Further, if the end face is also ground by grinding as in the capacitor manufacturing method described in the second claim, the above-mentioned effect of improving the electric strength characteristics is further enhanced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a capacitor manufactured according to an embodiment of the invention, FIG. 2 is a cross-sectional view of a capacitor manufactured according to a conventional example, and FIG. 3 is a cross-sectional view of a capacitor element after LA metallicon treatment. C... Capacitor, C4... Capacitor element,
DESCRIPTION OF SYMBOLS 1... Winding core, 2... Dielectric material, 3... Melt 1 metal layer, 11... End surface of winding core, 12... Inner peripheral surface of winding core.

Claims (2)

[Claims] 1. After applying metal spraying treatment to take out the electrodes on both sides of the capacitor element, which is made by winding and laminating a dielectric material around a cylindrical core, at least the inner peripheral surface of the core is ground and attached to the relevant part. A method for manufacturing a capacitor, characterized by removing sprayed metal. 2. 2. The method of manufacturing a capacitor according to claim 1, wherein the end surface of the core is ground as well as the inner circumferential surface of the core.