JPS6022599Y2 - CR composite parts - Google Patents

Description

[Detailed description of the invention] This invention is used in across-the-line circuits of electronic devices such as televisions and radios, and works to prevent noise caused by opening and closing of switches and eliminate sparks generated at contacts. Concerning CR composite parts to safely protect electronic equipment against inflow of voltage, specifically when used in Canadian Standards Association (C3A) Electrical Bulletin No. 975 radio, television and electronic equipment. This is a CR composite component that satisfies the requirements for across-the-line capacitors (hereinafter referred to as the C5A standard for simplicity).

The capacitance of the capacitor used in the across-the-line circuit is required to be an appropriate value for the design of electronic equipment, and is 0.033.
μF~0. A resistor with a resistance value of about IPF or 47Ω or 120Ω is often used.

The present invention proposes a CR composite component in which a cylindrical plastic film capacitor and a fixed fuse resistor (hereinafter referred to as the fuse resistor) with a porcelain tube exterior are connected in series and are coated with a flame-retardant exterior. It is.

By the way, among the conditions of the above-mentioned C3A standard, the item of fire test B is particularly problematic.

Fire test B involves applying a 4250 V peak AC or DC voltage across the capacitor terminals for 1 minute on 10 samples.

For samples with dielectric breakdown due to this test, a 125cm
Apply V AC directly.

This test stipulates that the cheesecloth should not burn or the fuse in the power supply circuit should not open.

Conventional CR composite parts using plastic film capacitors are made by connecting a self-healing metallized plastic film capacitor in series with a fixed body resistor (hereinafter referred to as body resistor) that is resistant to pulse voltage, and has a flame-retardant exterior. The one that is used is mainly used.

As will be explained in detail later, although the gold-containing plastic film capacitor has a self-recovery property when an abnormal voltage is applied, if the recovery is insufficient, the capacitor becomes unstable, close to a short circuit. Even though the body resistor is resistant to pulse voltage, a large current flows through it, so both the capacitor and the resistor generate heat, which often leads to smoke and then fire.

Used in order to satisfy the provisions of this fire test B.
It is possible to increase the thickness of the dielectric plastic film or increase the number of layers so that dielectric breakdown does not occur even when a 4250 V peak AC or DC voltage is applied for one minute.

However, if the thickness of the dielectric plastic film is increased or the number of layers is increased, the external dimensions of the capacitor will become significantly larger than the required capacitance.

This is because the amount of dielectric plastic film required to create a constant capacitance increases in proportion to the square of the thickness of the dielectric film used.

As the amount of dielectric material required increases, a critical drawback arises: the size of the capacitor becomes larger and the manufacturing cost increases.

On the other hand, in the C3A standard, there is a condition that 900V must be applied between both terminals of one capacitor for 1 minute, so the minimum thickness of the dielectric plastic film is limited by this condition. .

The present invention focuses on this point.

In other words, the present invention uses a dielectric plastic film and a metal electrode such as aluminum, instead of using a metallized plastic film, which tends to have unstable insulation even though it has self-recovery properties when abnormal voltage is applied, as in conventional products. A so-called plastic film capacitor made of foil is used, and a fuse resistor that automatically disconnects when a large current flows is used as a resistor, so a safe safety circuit is provided.

Therefore, it is possible to use a dielectric plastic film with the minimum thickness that satisfies the withstand voltage standard, and since the fuse resistor has a porcelain tube exterior, there is no risk of the porcelain tube being destroyed or the injected resin burning. It can be said that CR composite parts are highly safe against fires.

Therefore, the CR composite component according to the present invention satisfies the requirements for an across-the-line capacitor according to the C3A standard, and has the features of being small and inexpensive.

The features of the present invention will be explained in more detail by showing examples of the present invention below.

FIG. 1 is a wiring diagram of the CR composite part according to the present invention,
1 and 2 are the lead terminal numbers, C is the capacitor, and R is the fuse resistor.

Further, FIG. 2 is a front view showing the internal structure of the CR composite component according to the present invention, and FIG. 3 is a side view.

In FIGS. 2 and 3, C is a capacitor, R is a fuse resistor, 3 is a conductor connecting C and R, 4 is a flame-retardant exterior resin case made of resin such as polycarbonate, and 5 is made of epoxy resin, etc. Flame-retardant injection resin 6 and 7 are lead wires.

Further, W, H, and T are the width, height, and thickness dimensions of the exterior resin case 4.

In the embodiments shown in FIGS. 2 and 3, the resin case 4 and the injected resin 5 are used as the flame-retardant exterior, but the present invention is not limited to this. This includes dipping with flammable liquid resin or exterior coating with flame-retardant powder resin.

The capacitance value of the capacitor C is determined by the usage requirements as described above, and in practice, 0.033 μF and 0.01 μF are often adopted.

Also, as mentioned above, the withstand voltage value of capacitor C is A
It is necessary to withstand C900V for 1 minute, but C3
A dielectric film having a thickness of, for example, 12 μF, which can cause dielectric breakdown at 4250 V peak AC or DC specified in fire test B of Standard A is used.

In this case, the capacitor C is a so-called metal foil type plastic film capacitor in which a polyester film or the like and a metal electrode foil are alternately stacked and wound.

When using a capacitor wrapped with metallized plastic film, when 4250V peak AC or whip voltage is applied, the self-healing action of the capacitor prevents complete dielectric breakdown, and the current flows due to an arc, causing the dielectric to burn and become dangerous. be.

As the resistor R, from the viewpoint of flame retardancy, a fuse resistor covered with a porcelain tube is used.

The resistance value is determined depending on usage requirements, and as mentioned above, 120Ω or 47Ω are often used.

The rated power of the fuse resistor R may be about 1/2W.

Some fuse resistors have cement-dipped exteriors, but in C3A fire test B, the capacitors were destroyed, and the current would also blow the fixed fuse resistors, but the strength of the cement-dipped exterior was also weak, so they would fly apart. The energy generated also destroys the resin case and the filled resin, causing cracks.

At this time, since high voltage is applied to the fuse resistor, sparks are generated and heat is generated, which ignites the injected resin and burns it.

In the case of the fuse resistor which is removed by the porcelain tube of the present invention, by increasing the thickness of the porcelain tube, the phenomenon of the porcelain tube being destroyed or the injected resin burning does not occur.

As mentioned above, it consists of a combination of a foil plastic film capacitor and a fuse resistor with a porcelain tube exterior.
The CR composite component of the present invention with a flame-retardant exterior completely satisfies the C3A standard, and compared to conventional similar across-the-line capacitors, it has a fuse resistance with a porcelain tube exterior. The thickness of the dielectric plastic film can be kept to a minimum and it can therefore be made much smaller, making it easier to use in production and use.
It has great advantages and is of industrial value.

[Brief explanation of the drawing]

Figures 1 to 3 show examples of the present invention, and Figure 1...
...CR Wiring diagram of composite parts, Figure 2...CR
There is a front view of the composite part, and FIG. 3 is a side view of the CR composite part. 1.2...Lead terminal number, C...
Capacitor, R... Fuse resistor, J...
... Conductor connecting C and R, 4 ... Flame-retardant exterior resin case, 5 ... Flame-retardant injection resin, 6,
7...Lead wire.

Claims (1)

[Scope of utility model registration request] In the case of abnormal voltage application, a cylindrical plastic film capacitor that breaks down and forms a short circuit is connected in series with a fuse resistor with a porcelain tube exterior that breaks the circuit due to the current flowing through the short circuit. CR with exterior decoration
Composite parts.