JP2792916B2 - Noise filter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a noise filter inserted into a signal line or the like to remove noise.

(Prior Art) Conventionally, ferrite cores have been widely used for noise filters. This ferrite core is for low frequency (100KHz
Mn-Zn ferrite cores are used for high frequency (1 MHz or higher). this
A graph b in FIG. 1 shows an attenuation characteristic of an example of the Mn-Zn ferrite core, and a graph C in FIG. 1 shows an attenuation characteristic of an example of the Ni-Zn ferrite core. As can be seen from the graph of FIG. 1, the graph of the attenuation characteristics of the Mn-Zn-based ferrite core and the Ni-Zn-based ferrite core intersect at about 5 MHz, and at lower frequencies, the Mn-Zn-based ferrite core has At higher frequencies, the Ni-Zn ferrite core shows a high attenuation.

(Problems to be Solved by the Invention) As can be seen from FIG. 1, in a conventional noise filter, a Mn-Zn ferrite core is used when used in a low frequency region, and a Ni-Zn ferrite core is used when used in a high frequency region. The core and role are determined, and when used in a wide frequency band, it is necessary to use a combination of Mn-Zn ferrite core and Ni-Zn ferrite core, and one magnetic core is effective in a wide frequency band. A noise filter could not be constructed.

In view of the above, an object of the present invention is to provide a noise filter that can be used in a wide frequency band with one magnetic core.

(Means for Solving the Problems) The present invention relates to a method of forming a thin ribbon of an iron-based soft magnetic alloy in which at least 50% of the structure is a crystal grain having an average grain size of 500 mm or less when measured at the maximum dimension. This is a noise filter using a wound magnetic core.

This iron-based soft magnetic alloy has a general formula: (Fe _1-a M _a ) _{100-xyz-α-β-γ} Cu _x Si _y B _z M ′ _α M ″ _β X _γ (atomic%) (Where M is Co and / or Ni, and M ′ is Nb, W,
At least one element selected from the group consisting of Ta, Zr, Hf, Ti and Mo, wherein M ″ is V, Cr, Mn, Al, Pt group, S
c, Y, a rare earth element, at least one element selected from the group consisting of Au, Zn, Sn, and Re, and X is C, Ge, P, G
at least one element selected from the group consisting of a, Sb, In, Be, and As, wherein a, x, y, z, α, β, and γ are 0 ≦ a <0.5, 0.1 ≦ x ≦ 3, respectively. , 0 ≦ y ≦ 30, 0 ≦ z
≦ 24, 0 ≦ y + z ≦ 35, 0.1 ≦ α ≦ 30, 0 ≦ β ≦ 10 and 0 ≦ γ ≦ 10. ) Is obtained by quenching a molten metal having a composition represented by the formula (1) to form an amorphous alloy ribbon and subjecting it to heat treatment.

(Examples) The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 Width of a molten metal having a composition consisting of 1% of Cu, 3.4% of Sil, 3.1% of B, 3.1% of Nb and the balance of substantially Fe in atomic% by a single roll method.
A ribbon having a thickness of 12 mm and a thickness of 18 μm was produced. This ribbon was almost completely amorphous.

Next, a wound core having an inner diameter of 15 mm and 25 mm is formed from the amorphous ribbon, and the wound core is heat-treated at 540 ° C. for 1 hour in a nitrogen gas atmosphere having an oxygen concentration adjusted to 100 ppm. Was performed. The structure of the ribbon after the heat treatment was mostly composed of fine crystal grains, and the average grain size of the crystal grains was about 100 °. This winding core has a diameter
The attenuation characteristic was measured by winding a 1.5 mm copper wire for one turn, and the result was as shown in a graph a of FIG.

As is apparent from FIG. 1, the magnetic core of the present invention exhibits a much better attenuation in the low frequency region than the Mn-Zn ferrite core in the low frequency region, although it is slightly inferior to the Ni-Zn ferrite core in the high frequency region. ing. Therefore, the magnetic core of the present invention exhibits good attenuation characteristics over a wide range from low frequencies to high frequencies, and a single core of the present invention can constitute a noise filter corresponding to a wide range of frequencies. For example, when used for a noise filter used for a signal line, good results can be obtained.

(Effects of the Invention) According to the present invention, a noise filter corresponding to a wide range of frequencies can be constituted by one magnetic core, and is very useful, for example, it can be used as a noise filter for signal lines.

[Brief description of the drawings]

FIG. 1 is a graph showing attenuation characteristics of an embodiment according to the present invention and a conventional example.

Claims (1)

(57) [Claims] 1. A wound core formed by winding a thin ribbon of an iron-based soft magnetic alloy, in which at least 50% of the structure is a crystal grain having an average grain size of 500 ° or less when measured at the maximum dimension, in a toroidal shape. Characteristic noise filter.