JPS5919427Y2 - Combined surge absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite surge absorber comprising a capacitor and a non-linear resistor connected in parallel.

Generally, when an inductive load of an electronic device is switched on or off, there is a transient
A high surge voltage is generated due to the back electromotive force, which generates sparks between the switching contacts, which not only causes damage to circuit components (especially semiconductors) due to the surge voltage, but also wears out the contacts due to the sparks and causes noise. What is happening is widely recognized.

As a countermeasure for this, diodes or
A CR spark killer and a non-linear resistor such as a zinc oxide varistor are connected, but recently, in order to further suppress noise generation, a capacitor is connected in parallel to a zinc oxide varistor. It is beginning to be used as some parts.

By the way, conventionally, when attempting to absorb surges with a zinc oxide varistor and a capacitor, in the case of AC100V, a capacitor with a withstand voltage of 500V and a capacitance of 0.01 to 10μF and a zinc oxide varistor for AC100V are connected using lead wires. They were connected in parallel and used.

Normally, both of the above are large in shape because they do not even have a protective coating on each. Therefore, if you try to connect them in parallel as described above, the shape will be even larger, and this will result in a small electronic circuit. There was a problem that it could not be incorporated into the .

The present invention attempts to solve the above-mentioned conventional problems. For example, in a surge absorber in which the zinc oxide varistor and the capacitor are connected in parallel, the zinc oxide varistor and the capacitor are combined, and in that case, In order to make the shape as small as possible, a ceramic capacitor is used for the capacitor, and in order to increase the capacitance without reducing the withstand voltage as much as possible or increasing the shape, a cylindrical inner and outer structure with a large electrode facing area is used. In addition to adopting a side electrode structure, a zinc oxide varistor is placed in the air core in an attempt to make the shape of the composite as small as possible.

To further explain the present invention, as mentioned above, a ceramic capacitor is used as a capacitor so that it can be easily integrated with a zinc oxide varistor due to its shape. In order to make the capacitances as close as possible to each other to make it easier to downsize, the withstand voltage of the capacitor is lowered to near the limit voltage of the zinc oxide varistor on the other hand, and the distance between the electrodes is also reduced to correspond to the lowered withstand voltage. At the same time, by forming electrodes on the outer and inner surfaces of the cylindrical ceramic capacitor and increasing the area of the opposing electrodes, the required capacitance can be secured.

In order to facilitate miniaturization, the structure is such that the zinc oxide varistor is placed in the air center of the capacitor's cylinder as described above, while a metal case is used to integrate the zinc oxide varistor and the capacitor. At the same time, by devising the shape of the case, we have created a structure that allows the above-mentioned two to be connected in parallel simply by integrating the housing.

Furthermore, in this composite surge absorber, only the two metal cases, which also serve as external connection terminals, are exposed to the outside, and the other parts are molded with protective resin, making them weatherproof. It can also be made to have better sex.

Next, one embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 shows parts constituting a composite surge absorber which is an embodiment of the present invention, and FIG. 2 shows the same surge absorber.

In the figure, 1 is a round outer metal case, and it is sufficient to use an ordinary tin-plated iron plate.

A convex portion 11 is provided at the center bottom of the metal case 1, and its height is set so that it is connected to one electrode portion of a disc-shaped voltage nonlinear resistor to be described later.

Reference numeral 2 denotes a cylindrical resin insulator, which is assembled so that the cylindrical capacitor (to be described later), the outer metal case 1, the side surface of the voltage nonlinear resistor, and the inner metal case do not come into contact with each other.

The outer diameter of the insulator 2 is set to a size that allows it to be fitted inside the outer metal case 1, and the inner hole diameter is set to a size that allows the voltage nonlinear resistor to be sufficiently large.

Further, the outer peripheral surface of the insulator 2 is provided with a stepped portion 21 on its upper side into which the cylindrical capacitor can be fitted.

3 is a cylindrical capacitor, and electrodes 32 and 32' are formed on the outer and inner peripheral surfaces of a cylindrical ceramic dielectric 31, respectively.

Here, electrodes 32, 32 are placed on the outer circumferential surface and the inner circumferential surface like this.
' is effective in obtaining a wide electrode facing area.

The outer electrode 32 of this capacitor 3 may need to be strongly bonded to the inner circumferential surface of the outer metal case 1, both electrically and mechanically. In that case, apply cream solder to the electrode surface. It is also possible to connect the container 3 and the outer metal case 1 by heating after coating.

The inner electrode 32' may also need to be firmly bonded to the outer surface of the inner metal case, which will be described later. In that case, it may be connected with cream solder in the same way as the outer electrode 32. It is possible.

4 is a disc-shaped voltage nonlinear resistor using a zinc oxide varistor, and electrodes 41 and 41' are formed on both end faces.

Note that it is desirable to coat the side surfaces of the non-linear resistor 4 with an insulating resin to prevent creeping discharge.

This non-linear resistor 4 is arranged concentrically in the air center of the insulator 2.

As a result, the convex portion 11 of the outer metal case 1 is connected to one electrode 41 of the non-linear resistor 4 as described above.

Reference numeral 5 denotes a round inner metal case, and a convex portion 51 is formed at the center of the bottom face so as to face the outer metal case, and is connected to the other electrode 41' of the voltage nonlinear resistor 4. There is.

This connection may be made by crimping, but it is also possible to use cream solder as in the case of the capacitor 3.

The parts described above are assembled in sequence, and when using cream solder, the integration is completed by heating at 200 to 240°C for a few minutes, and even at this stage it can be put to practical use. As shown in Figure 2, if molding resin 6 is filled between the outer and inner metal cases 1 and 5 and cured, the only parts exposed to the outside are this molding resin and the outer and inner metal cases. , it has extremely good weather resistance.

As described above, according to the present invention, a cylindrical ceramic dielectric is used as a capacitor, and electrodes to be opposed to each other are provided on the inner and outer circumferential surfaces of the capacitor. In addition to ensuring sufficient capacitance, the structure in which a voltage nonlinear resistor is fitted into the air core of the dielectric material makes it extremely easy to downsize, making it ideal for electronic circuits where space is limited. It can be fully integrated.

In addition, since the voltage non-linear resistor and capacitor are connected in parallel through the metal case itself that houses them, resulting in a structure that does not use lead wires, the effective impedance to high frequency components is reduced, improving surge absorption performance. can be expected.

Furthermore, as described above, by filling the space between the outer metal case and the inner metal case with a molding resin, it is possible to provide extremely excellent weather resistance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of parts constituting a composite surge absorber which is an embodiment of the present invention, and FIG. 2 is a sectional view of the same surge absorber. 1... Outer metal case, 2... Insulator, 3... Capacitor, 4... Voltage nonlinear resistor, 5... Inner metal case, 6...
... Resin for mold, 11.51 ... Convex part, 3
1...Ceramic dielectric, 32.32', 4
1゜41'... Electrode.

Claims (4)

[Scope of utility model registration request] (1) A cylindrical ceramic dielectric body having electrodes facing each other formed on its outer side and inside side, and electrodes facing each other formed on its upper and lower surfaces, and in the air center of the ceramic dielectric body. The arranged voltage non-linear resistor and the ceramic dielectric are fitted so that the outer electrode of the ceramic dielectric is in contact with the inner side surface, and one electrode of the voltage non-linear resistor is in contact with the bottom surface. The bottomed cylindrical metal case is in contact with the ceramic dielectric body so that the inner electrode of the ceramic dielectric body is in contact with the outer side surface, and the other electrode of the voltage nonlinear resistor is in contact with the bottom surface of the ceramic dielectric body. A composite surge absorber comprising: a bottomed cylindrical inner metal case that is in contact with a cylindrical metal case; (2) Scope of a utility model registration claim in which a cylindrical insulator is arranged such that it has a stepped portion on the outside, the stepped portion fits into the outer metal case, and the main body portion fits into the inner metal case. No. (
The composite surge absorber described in item 1). (3) The composite surge absorber according to claim (1), wherein a resin is provided between the outer metal case and the inner case so as to cover the end face facing the outside of the ceramic dielectric. (4) Convex portions are provided on the bottom surfaces of both the outer and inner metal cases, and the convex portions are configured to be crimped to the upper and lower electrodes of the voltage non-linear resistor, respectively. ) Composite surge absorber described in item 2.