JPH05159836A - Terminal board with noise suppressing function - Google Patents

Abstract

PURPOSE:To prevent the ability of suppressing high frequency noise superposed on a DC current from lowering by causing magnetic saturation in ferrite beads with a large DC current flowing in an outside wiring. CONSTITUTION:A lead fitting 3 which is to be connected to an outside wiring via an attaching screw 2 has a U-shaped bent portion 3a in which thick cylindrical ferrite beads 4 are fitted. In this way, each leg of the U-shaped bent portion of the lead fitting 3 penetrates the hollow portion of the ferrite beads 4 in a reciprocal form so that DC currents flowing in the legs are reversed alternately to set off the intensity of a magnetic field against each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal block using thick cylindrical ferrite beads to suppress high frequency noise superposed on the DC current of the external wiring, and particularly strong DC current flowing in the external wiring. The present invention relates to a terminal block with a noise suppressing function, which prevents the ferrite beads from being magnetically saturated by an electric current and lowering the suppressing ability against high frequency noise.

[0002]

2. Description of the Related Art A conventional example will be described below with reference to the drawings. FIG. 3 is a perspective view of a conventional example. In FIG. 3, a terminal block 1 has a mounting screw 2 for external wiring (not shown).
Is provided, and the lead screw 8 is provided by the mounting screw 2.
Is connected to external wiring. 6 is a housing. The other end of the lead metal fitting 8 is connected to the printed wiring board 5, and the lead metal fitting 8 has a shape penetrating through the hollow portion of the thick-walled cylindrical ferrite bead 4 at the preceding position. This ferrite bead 4
Has a function of suppressing high-frequency noise as an AC component superimposed on the DC current of the external wiring.

FIG. 4 shows the operation of the conventional example, (a) is a substantial perspective view, and (b) is a principle perspective view. In FIG. 4 (b), two wires 7 through which current flows in the direction of the arrow respectively penetrate the ferrite beads 4. The high frequency noise as an alternating current component superimposed on the direct current flowing through any of the wires 7 is suppressed by the ferrite beads 4. That is,
The high-frequency noise changes the strength of magnetization of the ferrite beads 4, and accordingly, magnetic energy is accumulated in the ferrite beads 4, which becomes heat. In other words, high frequency noise is suppressed by the amount of heat. In FIG. 4A, the lead metal fitting 8 connected to an external wiring (not shown) penetrates the hollow portion of the ferrite bead 4. When a direct current flows through the lead metal fitting 8 in the direction of the arrow, the high frequency noise superimposed on the direct current is suppressed for the above reason.

[0004]

In the conventional example, when the direct current of the lead metal fitting 8 becomes large, for example, 2 A or more, the ferrite beads 4 are magnetically saturated, and the strength of magnetization changes due to the superimposed high frequency noise. However, there is a drawback that the function of suppressing high frequency noise is lowered.

The object of the present invention is to solve the above problems of the prior art, and to prevent the ferrite beads from being magnetically saturated by the strong direct current flowing through the external wiring, thereby reducing the suppression capability for high frequency noise. It is to provide a terminal block with a suppression function.

[0006]

A terminal block with a noise suppressing function according to a first aspect of the present invention uses a thick cylindrical ferrite bead to suppress high frequency noise superimposed on a direct current of external wiring. The lead metal fitting to be connected to the external wiring via the mounting screw has a U-shaped bent portion, and the ferrite bead is fitted into the bent portion.

[0007]

In the terminal block with a noise suppressing function according to the first aspect of the present invention, since each leg of the U-shaped bent portion of the lead metal fitting penetrates the hollow portion of the ferrite bead in a reciprocating manner, a DC current flowing through each leg is applied. Flow in directions opposite to each other, and the strengths of the magnetic fields based on them flow out to cancel each other, so that magnetic saturation of the ferrite beads does not easily occur.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a terminal block with a noise suppressing function according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the embodiment. In FIG. 1, this embodiment is different from the conventional example in that the lead metal fitting 3 has a U-shaped portion 3a formed by bending in a thinned portion in the front stage where the lead metal fitting 3 is connected to the printed wiring board 5. Ferrite beads 4
Is to be fitted. The left side shows a state before the ferrite beads 4 are moved and fitted in the U-shaped portion 3a in the arrow direction, and the right side shows a state in which the ferrite beads 4 are already fitted in the U-shaped portion 3a. The same members as those in the conventional example are designated by the same reference numerals.

FIG. 2 shows the operation of the embodiment, (a) is a substantial perspective view, and (b) is a principle perspective view. In FIG. 2B, two wirings 7 in which direct currents in opposite arrow directions flow through one ferrite bead 4, so that the strengths of the magnetic fields based on this are offset. Therefore,
A saturation state related to the magnetization intensity of the ferrite beads 4, that is, magnetic saturation hardly occurs. Therefore, the intensity of the magnetization of the ferrite beads 4 changes due to the high frequency noise superimposed on the direct current, and the magnetic energy is accumulated in the ferrite beads 4 accordingly, and this becomes further heat. In other words, the function of suppressing high-frequency noise works by the amount of heat. In FIG. 2 (a), the U-shaped portion 3a of the lead metal fitting 3 connected to an external wiring (not shown)
Are inserted and penetrated into the hollow portion of the ferrite bead 4.
Therefore, since each leg of the U-shaped portion 3a of the lead metal fitting 3 reciprocates through the hollow portion of the ferrite bead 4,
Direct currents flowing through the legs flow in opposite directions, and
For the same reason as described in (b), magnetic saturation of the ferrite beads 4 is less likely to occur, and the function of suppressing the high frequency noise superimposed on the DC current works.

[0010]

In the terminal block with a noise suppressing function according to the first aspect of the present invention, since each leg of the U-shaped bent portion of the lead metal fitting penetrates the hollow portion of the ferrite bead in a reciprocating manner, it flows through each leg. Direct currents flow in mutually opposite directions, and the strengths of the magnetic fields based on the direct currents cancel each other out, so that magnetic saturation of the ferrite beads becomes difficult to occur. As a result, even if the DC current becomes large, the high-frequency noise superimposed on the DC current changes the magnetization intensity of the ferrite beads, and accordingly, the magnetic energy is accumulated in the ferrite beads. Instead, the temperature of the ferrite beads rises. The suppression function for high frequency noise works by the amount of this heat.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment according to the present invention.

FIG. 2 shows the operation of the embodiment, (a) is a substantial perspective view,
(b) is a basic perspective view

FIG. 3 is a perspective view of a conventional example.

FIG. 4 shows an operation of a conventional example, (a) is a substantial perspective view,
(b) is a basic perspective view

[Explanation of symbols]

 1 terminal block 2 mounting screw 3 lead metal fitting 3a U-shaped portion 4 ferrite bead 5 printed wiring board 6 housing 7 wiring

Claims (1)

[Claims] 1. A terminal block using a thick-walled cylindrical ferrite bead to suppress high-frequency noise superimposed on a direct current of an external wiring, which should be connected to the external wiring via a mounting screw. A terminal block with a noise suppressing function, wherein the lead metal fitting has a U-shaped bent portion, and the ferrite bead is fitted into the bent portion.