JPH0310665Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a flat electrolytic capacitor using a metal exterior case.

Conventional technology Foil type electrolytic capacitors are made by forming a capacitor element by alternately overlapping and winding electrode foils on the anode side and cathode side and separator paper, and after impregnating this with an electrolyte, an aluminum plate is formed. It is enclosed in an outer case made of metal plates such as.

Generally, a capacitor element is formed in a cylindrical shape, and its outer case is also formed in a cylindrical shape, but there are cases where the capacitor element is flattened due to the relationship with the casing of an electronic device or the demand for miniaturization.

In this case, the capacitor element is wound into a cylindrical shape with a cavity in its center, formed into a flat shape, and then enclosed in a flat metal exterior case.

In addition, metal exterior cases are superior to those made of synthetic resin in terms of workability, mechanical strength, volumetric efficiency, and ease of maintaining airtightness, and are used in many electrolytic capacitors. .

However, when a metal exterior case is used, the electrolyte impregnated in the electrolytic capacitor has a low resistance value, so the exterior case and the electrode foil on the cathode side of the capacitor element are electrically connected through this electrolyte. It becomes a short-circuited state.

When such a short-circuit condition occurs, harmful spurious radiation may be generated from the outer case due to the alternating current and magnetic field flowing inside the capacitor element, which may cause noise to adjacent electronic circuits.

Therefore, the outer case is grounded, or the outer case is made of an aluminum plate laminated with a synthetic resin film on the surface that contacts the capacitor element.

Problems that the invention aims to solve When the outer case is grounded, noise generation can be reduced to some extent, but it is not possible to completely eliminate the effect on adjacent electronic circuits.

In addition, in the case of an exterior case with a synthetic resin film formed thereon, when cutting and molding an aluminum plate coated with a synthetic resin film, the synthetic resin film may peel off from the aluminum plate during the molding process, or the cut portions may Since there are parts where the synthetic resin film does not exist due to punching by pressing, etc., the molding process is troublesome, the insulation resistance decreases, and noise cannot be sufficiently reduced.

Therefore, the purpose of this invention is to provide an electrolytic capacitor that uses a flat metal exterior case and increases the insulation resistance between the capacitor element and the metal exterior case, thereby increasing the noise reduction effect. shall be.

Means for Solving the Problems In the electrolytic capacitor of this invention, a standing wall (standing wall plate 8) having a width narrower than the width of the bottom plate is formed at the periphery of a bottom plate 6 formed of a metal plate and having a square shape. a container part 3 having a presser part 12 formed on the edge thereof;
A lid plate 4 formed of a metal plate and installed opposite to the bottom plate of the container part, and a first interior part formed of an insulating synthetic resin in a flat plate shape and installed on the bottom plate side of the container part. a second interior body 26b formed of an insulating synthetic resin into a flat plate shape and installed on the lid plate side; and a flat interior body 26b installed between the first and second interior bodies. Capacitor element 40
and the first inner body is placed on the bottom plate side of the container portion, and the second inner body is placed on the lid plate side so as to be sandwiched between the bottom plate and the lid plate of the container portion. and a packing 24 for forming a sealed space for the capacitor element by crimping the presser part of the container part onto the upper surface of the lid plate.

Function: In this invention, a first interior body is installed on the container side that forms the outer case, a second interior body is installed on the lid plate side of the first interior body, and a capacitor element is installed in the sealed space formed by packing between them. Therefore, the insulation resistance between the capacitor element and the outer case is increased.

Embodiments Hereinafter, this invention will be explained in detail with reference to the drawings.

1 and 2 show a flat electrolytic capacitor which is an embodiment of this invention, FIG. 1 is an exploded perspective view thereof, and FIG. 2 is a perspective view showing its external shape.

In FIG. 1, the metal exterior case 2 consists of a container part 3 and a lid plate 4, both of which are made of an aluminum plate.
It is made of a metal plate such as a steel plate.

In the container part 3, a standing wall plate 8 having a width narrower than the width of the bottom plate 6 is integrally formed on the four sides of a bottom plate 6 having a rectangular shape formed of a metal plate. A plurality of thin slits 10 are formed at regular intervals at the bending part with the plate 8 to facilitate the bending, and a vertical wall plate 8 is formed at the tip of the vertical wall plate 8 to hold the lid plate 4. A presser portion 12 is formed which is bent to form a dogleg shape.

Further, the bottom plate 6 is formed with hemispherical protrusions 14 and 16 that protrude from the inner surface thereof, and each protrusion 1
A terminal hole 22 is formed in the center of each of the terminal holes 4 and 16 for attaching the rivet terminals 18 and 20 on the anode side or the cathode side.

Then, as shown in FIG. 1, the standing wall board 8 is bent and raised, and the angle with the bottom board 6 is set to be close to 90 degrees.

Inside the container portion 3 thus formed, a packing 24 is provided in order to form a sealed space in which the capacitor element 40 is to be housed, and a packing 24 is provided inside the container portion 3 formed in this manner. 1
and second inner bodies 26a and 26b are provided, the inner body 26a being disposed on the bottom plate 6 side of the container portion 3, and the inner body 26b being disposed on the lid plate 4 side. The packing 24 is made of an airtight elastic material such as rubber and forms a rectangular frame corresponding to the bottom plate 6. Also,
The interior bodies 26a and 26b are molded with synthetic resin such as polyethylene or polypropylene, and are made of 0.06 mm to prevent the volume of the exterior case 2 from being significantly reduced.
A material having a thickness of about 1 mm can be used.

The inner bodies 26a and 26b of this embodiment are formed to match the shapes of the bottom plate 6 and the lid plate 4 of the container part 3 so that the packing 24 can be gripped at the peripheral edges thereof. That is, the inner body 26a is formed with protrusions 34 and 36 that cover the protrusions 14 and 15 at positions that match the protrusions 14 and 16 of the outer case 2, and a through hole 38 is formed in the center of the protrusions 34 and 36. There is.

In addition, the capacitor element 40 is made by winding electrode foils on the anode side and the cathode side and separator paper in an alternately overlapping manner, and impregnating the inside with an electrolytic solution, and a terminal connection is provided at the end. Therefore, the tabs 42 and 44 are pulled out.

Then, as shown in FIG. 3, after installing the inner body 26a inside the container part 3, the capacitor element 4
Set 0. The rivet portions 46 of the rivet terminals 18 and 20 are inserted from the outside of the container portion 3 into the terminal holes 22 of the protruding portions 14 and 16 of the container portion 3 of the exterior case 2, and the flange portions 48 of the rivet portions 46 are A packing 50 made of an insulating material such as rubber is attached to the upper surface of the rivet portion 46 and the container portion 3 to electrically insulate the rivet portion 46 and the container portion 3.

A synthetic resin washer 52 is attached to the rivet portion 46 protruding into the interior of the container portion 3, and the tabs 42, 44 are attached so as to be sandwiched between the metal washers 54, 56, and then each rivet portion 46 is attached.
are swaged to fix the rivet terminals 18, 20 to the container part 3, and also tighten the rivet terminals 18, 20.
and the tabs 42, 44 are electrically connected.

After installing the interior body 26b on the top surface of the packing 24, the lid plate 4 is placed on the top surface of the interior body 26b,
Raise the standing wall plate 8 from its peripheral direction so that the angle with the bottom plate 6 is at right angles, as shown in FIG.
A presser portion 12 at the tip thereof is crimped and locked onto the upper edge of the cover plate 4. As a result, the lid plate 4 is pressed against the packing 24 by the pressing part 12 of the container part 3, and the airtightness of the container part 3 is maintained.

According to such a configuration, an airtight container part insulated from the outer case 2 by the inner bodies 26a, 26b and the packing 24 is formed inside the metal outer case 2, and the capacitor element 4 is placed inside the airtight container part.
0 is set. That is, the insulation resistance between the inner wall of the exterior case 2 and the capacitor element 40 can be increased by the insulating material forming the interior bodies 26a and 26b, suppressing spurious radiation and suppressing adjacent electrons. The influence of noise on the circuit can be removed.

Moreover, if the exterior case 2 is grounded, the noise reduction effect due to the grounding is added, and the generation of noise can be suppressed more effectively.

According to experiments, the inner bodies 26a and 26b have a thickness
Using a 0.2 mm polyethylene plate, connect the electrode foils on the anode and cathode sides of the capacitor element 40 in common, and measure the insulation resistance by applying 500 V between this common electrode foil and the exterior case 2. if you did this,
A resistance value of about 10 ¹¹ to ^{10 12} Ω is obtained, but on the other hand, when the insulation resistance value is measured with an electrolytic capacitor without an inner body installed, the value is about 100 Ω. As a result of this experiment, the interior bodies 26a, 26
It was confirmed that a considerably high insulation resistance value could be obtained by installing b.

Moreover, the interior body 26a, as shown in FIG.
A standing wall 60 may be provided around the rectangular bottom plate 58 to form an inner container part that can be installed in the internal space of the packing 24, and the inner body 26b may be a lid part that closes this container part.

In this way, as shown in FIG. 5, the inner wall of the packing 24 can be covered with the vertical wall 60 of the interior body 26a, and contact between the packing 24 and the electrolyte can be avoided, and the packing 24 can be prevented from coming into contact with the electrolyte.
This is advantageous in that it is possible to prevent impurities from flowing out from 4.

Effects of the invention As explained above, according to this invention, the first interior body is installed on the container side and the second interior body is installed on the lid plate side, and the packing is sandwiched between the two to form an airtight space, and the interior of the airtight space is formed. Since the capacitor element is sealed, the outer case that maintains airtightness and the inner body that increases insulation are separate parts, compared to the conventional outer case that uses a metal plate with a synthetic resin film. It is possible to sufficiently increase the insulation resistance between the capacitor element and the container part and the cover plate, and the noise generated from the capacitor element can be effectively blocked by the increase in insulation resistance. type electrolytic capacitors.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing an embodiment of the electrolytic capacitor of this invention, Fig. 2 is a perspective view showing its external shape, Fig. 3 is a partially omitted sectional view of the electrolytic capacitor, and Fig. 4 is the interior of the electrolytic capacitor. FIG. 5 is an exploded perspective view showing another embodiment of the body, and FIG. 5 is a sectional view showing an electrolytic capacitor using the inner body shown in FIG. 4. 3... Container part, 4... Lid plate, 6... Bottom plate, 8...
... Standing wall board (standing wall), 12... Holding part, 26a...
First interior body, 26b...Second interior body, 40...
...Capacitor element.

Claims (1)

[Claims for Utility Model Registration] A container portion formed of a metal plate, having a rectangular bottom plate with a vertical wall having a width narrower than the width of the bottom plate formed on the periphery of the bottom plate, and a presser portion formed on the edge of the vertical wall; a lid plate formed of a metal plate and installed opposite to the bottom plate of the container part; and a first inner body formed of an insulating synthetic resin in a flat plate shape and installed on the bottom plate side of the container part. a second interior body made of insulating synthetic resin in a flat plate shape and installed on the cover plate side; and a flat capacitor element installed between the first and second interior bodies. , the first inner body on the bottom plate side of the container part,
It is installed on the lid plate side via the second inner body between the bottom plate of the container part and the lid plate, and the presser part of the container part is applied to the upper surface of the lid plate. An electrolytic capacitor comprising: a packing that is tightened to form a sealed space for the capacitor element.